Scientific Journal`s

New clue to how last ice age ended

2010-09-09T15:28:00.000+07:00

As the last ice age was ending, about 13,000 years ago, a final blast of cold hit Europe, and for a thousand years or more, it felt like the ice age had returned. But oddly, despite bitter cold winters in the north, Antarctica was heating up. For the two decades since ice core records revealed that Europe was cooling at the same time Antarctica was warming over this thousand-year period, scientists have looked for an explanation.

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A new study in Nature brings them a step closer by establishing that New Zealand was also warming, indicating that the deep freeze up north, called the Younger Dryas for the white flower that grows near glaciers, bypassed much of the southern hemisphere.

"Glaciers in New Zealand receded dramatically at this time, suggesting that much of the southern hemisphere was warming with Antarctica," said study lead author, Michael Kaplan, a geochemist at Columbia University's Lamont-Doherty Earth Observatory. "Knowing that the Younger Dryas cooling in the northern hemisphere was not a global event brings us closer to understanding how Earth finally came out of the ice age."

Ice core records show that warming of the southern hemisphere, starting 13,000 years ago, coincided with rising levels of the heat-trapping gas, carbon dioxide. The study inNature is the first to link this spike in CO₂ to the impressive shrinking of glaciers in New Zealand. The scientists estimate that glaciers lost more than half of their extent over a thousand years, and that their creep to higher elevations was a response to the local climate warming as much as 1 degree C.

To reconstruct New Zealand's past climate, the study's authors tracked one glacier's retreat on South Island's Irishman Basin. When glaciers advance, they drag mounds of rock and dirt with them. When they retreat, cosmic rays bombard these newly exposed ridges of rock and dirt, called moraines. By crushing this material and measuring the build-up of the cosmogenic isotope beryllium 10, scientists can pinpoint when the glacier receded. The beryllium-10 method allowed the researchers to track the glacier's retreat upslope through time and indirectly calculate how much the climate warmed.

The overall trigger for the end of the last ice age came as Earth's orientation toward the sun shifted, about 20,000 years ago, melting the northern hemisphere's large ice sheets. As fresh melt water flooded the North Atlantic Ocean, the Gulf Stream weakened, driving the north back into the ice age. During this time, temperatures in Greenland dropped by about 15 degrees C. For years, scientists have tried to explain how the so-called Younger Dryas cooling fit with the simultaneous warming of Antarctica that eventually spread across the globe.

The Nature paper discusses the two dominant explanations without taking sides. In one, the weakening of the Gulf Stream reconfigures the planet's wind belts, pushing warm air and seawater south, and pulling carbon dioxide from the deep ocean into the air, causing further warming. In the other, the weakened Gulf Stream triggers a global change in ocean currents, allowing warm water to pool in the south, heating up the climate.

Bob Anderson, a geochemist at Lamont-Doherty who argues the winds played the dominant role, says the Nature paper adds another piece to the puzzle. "This is one of the most pressing problems in paleoclimatology because it tells us about the fundamental processes linking climate changes in the northern and southern hemispheres," he said. "Understanding how regional changes influence global climate will allow scientists to more accurately predict regional variations in rain and snowfall."

Other researchers involved in the study: Joerg Schaefer and Roseanne Schwartz, also of Lamont-Doherty; George Denton and Aaron Putnam, University of Maine; David Barrell, GNS Science, New Zealand; Trevor Chinn, Alpine and Polar Processes Consultancy, New Zealand; Bjørn Andersen, University of Oslo; Robert Finkel, University of California, Berkeley; Alice Doughty, Victoria University of Wellington.

http://www.sciencedaily.com/releases/2010/09/100908132214.htm

Journal Impact Factors

2010-09-09T15:20:00.001+07:00

Journal Impact Factor is from Journal Citation Report (JCR), a product of Thomson ISI (Institute for Scientific Information). JCR provides quantitative tools for evaluating journals. The impact factor is one of these; it is a measure of the frequency with which the "average article" in a journal has been cited in a given period of time.

The impact factor for a journal is calculated based on a three-year period, and can be considered to be the average number of times published papers are cited up to two years after publication. For example, the impact factor 2010 for a journal would be calculated as follows:

A = the number of times articles published in 2008-9 were cited in indexed journals during 2010

B = the number of articles, reviews, proceedings or notes published in 2008-2009

impact factor 2010 = A/B

(note that the impact factor 2009 will be actually published in 2010, because it could not be calculated until all of the 2009 publications had been received. Impact factor 2010 will be published in 2011)

Impact factor of Nature, Science and Cell journals can be found on their journal websites.

The lists of Impact Factors have been removed from this site due to copy right violations. Sci-Bytes provides ranking and impact factor for selective journals. The list is located here:
http://www.sciencegateway.org/rank/index.html

Ilmiah tapi Tak Masuk Akal

2008-06-15T11:20:00.002+07:00

Bisakah air diolah menjadi bahan bakar? Dulu ada sseseorang yang menyatakan sanggup untuk mewujudkan bahan bakar dari air. Bahkan ide ini sempat dipatenkan (dalam proses) oleh Universitas yang sudah terkenal di yogyakarta.

Berita adanya penemuan yang menyatakan air bisa dijadikan bahan bakar seolah2 menjadi obat luka akibat kenaikan BBM yang sangat tidak memihak rakyat. Tapi ternyata obat yang tadinya terasa sangat membantu ini adalah sebuah kebohongan ilmiah. Bagaimana tidak, daam sebuah laporan yang diberitakan oleh sebuah portal berita. Disebutkan bahwa penemua tersebut adalah akal-akalan dan ada unsur kebohongan.

Yang menjadi pertanyaan buat saya sendiri adalah. Kenapa pihak Universitas tersebut yang nota bene berbasis Islam begitu saja percaya dengan adanya :"anyu Geni" dan PLTM yang disebut oleh para peneliti dari UGM sebagai Pembangkit Listrik Tenaga "JIN".

Semoga kejadian ini menjadi pelajaran buat kita semua. Jangan mudah percaya dengan sesuatu yang belum ada buktinya.

Isolasi dan Karakterisasi Amilase dari Kapang Alkalotoleran Asal Limbah Cair Tapioka

2008-05-19T09:20:00.002+07:00

Nisa Rachmania Mubarik, Evi Damayanti & Sri Listyowati

Jurusan Biologi, FMIPA, Institut Pertanian Bogor, Jalan Raya Pajajaran , Bogor 16144 Tel./Fax. +62-251-345011, E-mail: riknisa@telkom.net

Abstract

A total of 6 fungi isolates of growing at pH 9 and 2 isolates on pH 10 with amylolytic indexes 0f 0.07-1.42 have been isolated from cassava starch liquid waste. Two isolates having the highest amylolytic index were identified as Aspergillus sydowii K10 (1.42) and Aspergillus versicolor L30 (1.4). Both A. sydowii K10 and A. versicolor L30 were described as alcalotolerant for being able to grow with range pH 5-10. The optimal -amylases production of A. sydowii K10 and A. versicolor L30 was obtained after 4 and 3 days of incubation at 30⁰C. The optimum of -amylase activity from A. sydowii K10 was at 40⁰C and 70⁰C, and pH 6; while those from A. versicolor L30 was at 50⁰C and pH 6 respectively. Both A. sydowii K10 and A. versicolor L30 could produce glucoamylase. The optimum of glucoamylase activity from A. sydowii K10 was at 40⁰C and pH 5, while those from A. versicolor L30 was at 50⁰C and pH 5 respectively.

Key words : characterization, -amylase, glucoamylase, Aspergillus sydowii, Aspergillus versicolor.

Maaf, artikelnya cuma tersedia dalam bentuk abstraknya saja. Klo mau yanglengkapnya, silahkan menghubungi contact person di atas.

Neural Mechanisms of Extinction Learning and Retrieval

2007-12-04T06:12:00.000+07:00

Neuropsychopharmacology Reviews

Neuropsychopharmacology (2008) 33, 56–72; doi:10.1038/sj.npp.1301555; published online 19 September 2007

Neural Mechanisms of Extinction Learning and Retrieval

Gregory J Quirk1 and Devin Mueller1
1Department of Psychiatry, University of Puerto Rico School of Medicine, San Juan, Puerto Rico
Correspondence: Dr GJ Quirk, Department of Psychiatry, University of Puerto Rico School of Medicine, PO Box 365067, San Juan 00936-5067, Puerto Rico. Tel: +1 787 999 3058; Fax: +1 787 999 3057; E-mail: gjquirk@yahoo.com
Received 15 May 2007; Revised 11 July 2007; Accepted 29 July 2007; Published online 19 September 2007.

Abstract

Emotional learning is necessary for individuals to survive and prosper. Once acquired, however, emotional associations are not always expressed. Indeed, the regulation of emotional expression under varying environmental conditions is essential for mental health. The simplest form of emotional regulation is extinction, in which conditioned responding to a stimulus decreases when the reinforcer is omitted. Two decades of research on the neural mechanisms of fear conditioning have laid the groundwork for understanding extinction. In this review, we summarize recent work on the neural mechanisms of extinction learning. Like other forms of learning, extinction occurs in three phases: acquisition, consolidation, and retrieval, each of which depends on specific structures (amygdala, prefrontal cortex, hippocampus) and molecular mechanisms (receptors and signaling pathways). Pharmacological methods to facilitate consolidation and retrieval of extinction, for both aversive and appetitive conditioning, are setting the stage for novel treatments for anxiety disorders and addictions.

Keywords:
infralimbic cortex, amygdala, fear conditioning, glutamate receptors, bursting, PTSD

Cellular Plasticity Cascades in the Pathophysiology and Treatment of Bipolar Disorder

2007-12-04T06:07:00.000+07:00

Neuropsychopharmacology Reviews
Neuropsychopharmacology (2008) 33, 110–133; doi:10.1038/sj.npp.1301575; published online 3 October 2007

Cellular Plasticity Cascades in the Pathophysiology and Treatment of Bipolar Disorder

Robert J Schloesser1,3, Jian Huang2,3, Peter S Klein2 and Husseini K Manji1

1Laboratory of Molecular Pathophysiology, Mood and Anxiety Disorders Program, National Institute of Mental Health, NIH, Bethesda, MD, USA
2Department of Medicine (Hematology-Oncology), University of Pennsylvania School of Medicine, Philadelphia, PA, USA
Correspondence: Dr HK Manji, Laboratory of Molecular Pathophysiology, Mood and Anxiety Disorders Program, National Institute of Mental Health, Porter Neuroscience Research Center, Building 35, Room 1C-917, 35 Convent Drive, Bethesda, MD 20892, USA. Tel: +1 301 496 9802; Fax: +1 301 480 0123; E-mail: manjih@mail.nih.gov
3Dr Schloesser and Dr Huang share first authorship.
Received 16 July 2007; Revised 1 August 2007; Accepted 14 August 2007; Published online 3 October 2007.

Abstract

Bipolar disorder (BPD) is characterized by recurrent episodes of disturbed affect including mania and depression as well as changes in psychovegetative function, cognitive performance, and general health. A growing body of data suggests that BPD arises from abnormalities in synaptic and neuronal plasticity cascades, leading to aberrant information processing in critical synapses and circuits. Thus, these illnesses can best be conceptualized as genetically influenced disorders of synapses and circuits rather than simply as deficits or excesses in individual neurotransmitters. In addition, commonly used mood-stabilizing drugs that are effective in treating BPD have been shown to target intracellular signaling pathways that control synaptic plasticity and cellular resilience. In this article we draw on clinical, preclinical, neuroimaging, and post-mortem data to discuss the neurobiology of BPD within a conceptual framework while highlighting the role of neuroplasticity in the pathophysiology and treatment of this disorder.

Keywords:
bipolar disorder, neuroplasticity, intracellular signaling cascades, lithium, valproic acid, mood stabilizer

Drug Addiction as a Pathology of Staged Neuroplasticity

2007-12-04T06:03:00.000+07:00

Neuropsychopharmacology Reviews
Neuropsychopharmacology (2008) 33, 166–180; doi:10.1038/sj.npp.1301564; published online 5 September 2007
Drug Addiction as a Pathology of Staged Neuroplasticity
Peter W Kalivas1 and Charles O'Brien2
1Departments of Neurosciences, Medical University of South Carolina, Charleston, SC, USA
2Department of Psychiatry, Philadelphia VA Medical Center, University of Pennsylvania, Philadelphia, PA, USA
Correspondence: Dr P Kalivas, Departments of Neurosciences, Medical University of South Carolina, 173 Ashley Ave, BSB 410, Charleston, SC 29425, USA. Tel: +1 843 792 4400; Fax: +1 843 792 4423; E-mail: kalivasp@musc.edu
Received 12 July 2007; Revised 8 August 2007; Accepted 8 August 2007; Published online 5 September 2007.

Abstract

Using addictive drugs can evolve from controlled social use into the compulsive relapsing disorder that characterizes addiction. This transition to addiction results from genetic, developmental, and sociological vulnerabilities, combined with pharmacologically induced plasticity in brain circuitry that strengthens learned drug-associated behaviors at the expense of adaptive responding for natural rewards. Advances over the last decade have identified the brain circuits most vulnerable to drug-induced changes, as well as many associated molecular and morphological underpinnings. This growing knowledge has contributed to an expanded understanding of how drugs usurp normal learning circuitry to create the pathology of addiction, as evidenced by involuntary activation of reward circuits in response to drug-associated cues and simultaneous reports of drug craving. This new understanding provides unprecedented potential opportunities for novel pharmacotherapeutic targets in treating addiction. There appears to be plasticity associated with the addiction phenomenon in general as well as changes produced by addiction to a specific class of addicting drugs. These findings also provide the basis for the current understanding of addiction as a chronic, relapsing disease of the brain with changes that persist long after the last use of the drug. Here, we describe the neuroplasticity in brain circuits and cell function induced by addictive drugs that is thought to underlie the compulsions to resume drug-taking, and discuss how this knowledge is impelling exploration and testing of novel addiction therapies.

Keywords:
addiction, neuroplasticity, motivational circuitry, glutamate, dopamine

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2007-12-02T09:39:00.001+07:00

2007-11-26T05:59:00.000+07:00

Technorati Profile

The Functional Genomics Experiment model (FuGE): an extensible framework for standards in functional genomics

2007-11-25T03:32:00.000+07:00

Perspective
Nature Biotechnology 25, 1127 - 1133 (2007) Published online: 5 October 2007 doi:10.1038/nbt1347
The Functional Genomics Experiment model (FuGE): an extensible framework for standards in functional genomics
Andrew R Jones1,2,16, Michael Miller3, Ruedi Aebersold4,5, Rolf Apweiler6, Catherine A Ball7, Alvis Brazma6, James DeGreef8, Nigel Hardy9, Henning Hermjakob6, Simon J Hubbard2, Peter Hussey10, Mark Igra10, Helen Jenkins9, Randall K Julian, Jr11, Kent Laursen11, Stephen G Oliver2, Norman W Paton1, Susanna-Assunta Sansone6, Ugis Sarkans6, Christian J Stoeckert, Jr12, Chris F Taylor6, Patricia L Whetzel12, Joseph A White13, Paul Spellman14 & Angel Pizarro15,16
Abstract
The Functional Genomics Experiment data model (FuGE) has been developed to facilitate convergence of data standards for high-throughput, comprehensive analyses in biology. FuGE models the components of an experimental activity that are common across different technologies, including protocols, samples and data. FuGE provides a foundation for describing entire laboratory workflows and for the development of new data formats. The Microarray Gene Expression Data society and the Proteomics Standards Initiative have committed to using FuGE as the basis for defining their respective standards, and other standards groups, including the Metabolomics Standards Initiative, are evaluating FuGE in their development efforts. Adoption of FuGE by multiple standards bodies will enable uniform reporting of common parts of functional genomics workflows, simplify data-integration efforts and ease the burden on researchers seeking to fulfill multiple minimum reporting requirements. Such advances are important for transparent data management and mining in functional genomics and systems biology.

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Effects of Torcetrapib in Patients at High Risk for Coronary Events

2007-11-25T03:22:00.000+07:00

Philip J. Barter, M.D., Ph.D., Mark Caulfield, M.D., M.B., B.S., Mats Eriksson, M.D., Ph.D., Scott M. Grundy, M.D., Ph.D., John J.P. Kastelein, M.D., Ph.D., Michel Komajda, M.D., Jose Lopez-Sendon, M.D., Ph.D., Lori Mosca, M.D., M.P.H., Ph.D., Jean-Claude Tardif, M.D., David D. Waters, M.D., Charles L. Shear, Dr.P.H., James H. Revkin, M.D., Kevin A. Buhr, Ph.D., Marian R. Fisher, Ph.D., Alan R. Tall, M.B., B.S., Bryan Brewer, M.D., Ph.D., for the ILLUMINATE Investigators

ABSTRACT
Background Inhibition of cholesteryl ester transfer protein (CETP) has been shown to have a substantial effect on plasma lipoprotein levels. We investigated whether torcetrapib, a potent CETP inhibitor, might reduce major cardiovascular events. The trial was terminated prematurely because of an increased risk of death and cardiac events in patients receiving torcetrapib.
Methods We conducted a randomized, double-blind study involving 15,067 patients at high cardiovascular risk. The patients received either torcetrapib plus atorvastatin or atorvastatin alone. The primary outcome was the time to the first major cardiovascular event, which was defined as death from coronary heart disease, nonfatal myocardial infarction, stroke, or hospitalization for unstable angina.
Results At 12 months in patients who received torcetrapib, there was an increase of 72.1% in high-density lipoprotein cholesterol and a decrease of 24.9% in low-density lipoprotein cholesterol, as compared with baseline (P<0.001 for both comparisons), in addition to an increase of 5.4 mm Hg in systolic blood pressure, a decrease in serum potassium, and increases in serum sodium, bicarbonate, and aldosterone (P<0.001 for all comparisons). There was also an increased risk of cardiovascular events (hazard ratio, 1.25; 95% confidence interval [CI], 1.09 to 1.44; P=0.001) and death from any cause (hazard ratio, 1.58; 95% CI, 1.14 to 2.19; P=0.006). Post hoc analyses showed an increased risk of death in patients treated with torcetrapib whose reduction in potassium or increase in bicarbonate was greater than the median change.
Conclusions Torcetrapib therapy resulted in an increased risk of mortality and morbidity of unknown mechanism. Although there was evidence of an off-target effect of torcetrapib, we cannot rule out adverse effects related to CETP inhibition. (ClinicalTrials.gov number, NCT00134264 [ClinicalTrials.gov] .)
Evidence supporting the proposition that high-density lipoprotein (HDL) cholesterol should be considered as a therapeutic target includes experimental models of atherosclerosis,1 an inverse relationship to the risk of cardiovascular disease in humans,2 clinical trials of drugs for which raising HDL cholesterol levels is a primary pharmacologic effect,3 and the residual risk of cardiovascular disease associated with a low HDL cholesterol level after effective statin therapy.4
Cholesteryl ester transfer protein (CETP) promotes the transfer of cholesteryl esters from HDL to other lipoproteins; the inhibition of this protein raises HDL cholesterol levels and decreases low-density lipoprotein (LDL) cholesterol levels. There is evidence supporting CETP inhibition as a therapeutic approach to the prevention of major cardiovascular events, although there is also evidence to the contrary.5,6,7
Torcetrapib is an inhibitor of CETP that has been shown to inhibit the development of atherosclerosis in rabbits.8 In early-phase studies in humans, the drug increased HDL cholesterol by 60 to 100% at the same time that it lowered LDL cholesterol by up to 20%.9,10 Torcetrapib was subsequently investigated in three large trials with the use of ultrasonography and other imaging techniques and was found to have no significant effect on coronary atheroma burden11 or carotid intima–media thickness.12,13 Concurrent with these imaging studies, the Investigation of Lipid Level Management to Understand its Impact in Atherosclerotic Events (ILLUMINATE) trial tested the proposition that torcetrapib would decrease the risk of clinical cardiovascular events. This trial was terminated prematurely on December 2, 2006, in a decision made by the sponsor on the basis of the recommendation of the trial's independent steering committee, which was acting on advice from the independent data and safety monitoring board.14 This report describes the main results of the ILLUMINATE trial.
Methods
Study Design
We conducted a prospective, randomized, multicenter, double-blind clinical trial, using a centralized randomization strategy with a block size of four. The trial was designed by an independent steering committee in collaboration with the sponsor, Pfizer. Data were collected by PharmaNet Development Group and analyzed independently by the Statistical Data Analysis Center at the University of Wisconsin, Madison; representatives of these organizations vouch for the completeness and veracity of the data and the analyses, respectively. An institutional review board at each center approved the protocol, and patients provided written informed consent. The original protocol was amended on November 28, 2006, a change that had not yet received institutional review board approval at the time of the trial's termination. The amendment included the addition of hospitalization for unstable angina to the primary outcome to increase the number of events and thus increase the statistical power to reject the null hypothesis.
Men and women between the ages of 45 and 75 years were eligible to participate in the study if they had a history of cardiovascular disease (including myocardial infarction, stroke, acute coronary syndrome, unstable angina, peripheral vascular disease, and cardiac revascularization) 30 days to 5 years before screening. Patients with type 2 diabetes without previous cardiovascular disease who met American Diabetes Association criteria or were receiving hypoglycemic agents were also eligible. Patients were excluded if they had evidence of an unstable medical condition, a life expectancy of less than 5 years, or an LDL cholesterol level of less than 100 mg per deciliter (2.6 mmol per liter) if the patient was not receiving a lipid-altering drug. Patients were also excluded if they had had a cardiovascular event during the run-in period or uncontrolled hypertension (defined as a systolic blood pressure of >140 mm Hg or a diastolic blood pressure of >90 mm Hg) or if the LDL cholesterol target level had not been reached at the end of the run-in period.
During a run-in period of 4 to 10 weeks, patients underwent lifestyle counseling and also received atorvastatin titrated (if needed) at 2-week intervals to achieve an LDL cholesterol level of less than 100 mg per deciliter. A variability tolerance of +15 mg per deciliter (0.4 mmol per liter) was allowed. Patients whose LDL level met the target were randomly assigned to receive either atorvastatin (at a dose established during the run-in period) plus 60 mg of torcetrapib or atorvastatin plus placebo. After termination of the trial, the sponsor maintained support for independent oversight during the trial's closeout (which involved four of the academic authors) with continuing support from the Statistical Data Analysis Center, which performed the primary statistical analyses.
Study Outcomes
Patients' visits were scheduled at 1, 3, 6, 9, and 12 months after randomization. Thereafter, patients were to be seen twice yearly. An increase or decrease in the dose of atorvastatin was allowed at the 12-month visit on the basis of predefined LDL cholesterol levels. The level of HDL cholesterol was determined through enzyme analysis with the use of polyethylene glycol–modified cholesterol esterase, cholesterol oxidase, and dextran sulfate to generate peroxide that was measured calorimetrically. Total cholesterol and triglyceride levels were determined by standard enzymatic techniques. LDL cholesterol was quantified by the Friedewald formula, except when the triglyceride level was more than 400 mg per deciliter (4.5 mmol per liter), in which case the level was measured by direct beta quantification. Apolipoproteins A-I and B-100 were measured by means of immunoturbidimetric assay. High-sensitivity C-reactive protein (CRP) was measured with the use of a particle-enhanced immunoturbidimetric assay. All measurements were performed at a central laboratory (MDS). Blood pressure was measured in triplicate at each visit with the use of a standard calibrated measuring device with the patient seated after 5 minutes of rest. The first reading was not used, and the latter two readings were averaged for the visit measurement. The estimated glomerular filtration rate was calculated as described previously.15
The QT interval was calculated with the use of Bazett's correction. A decision to measure aldosterone was made after termination of the trial after investigators observed a pattern of change in serum electrolytes and blood pressure. Stored serum samples that had been obtained from patients at baseline and at 3 months were used, with measurements made by means of liquid chromatography–tandem mass spectrometry (Mayo Central Laboratory for Clinic Trials).
Efficacy Measures
The primary outcome was the time to the first occurrence of a major cardiovascular event, a composite that included four components: death from coronary heart disease (defined as fatal myocardial infarction excluding procedure-related events, fatal heart failure, sudden cardiac death, or other cardiac death), nonfatal myocardial infarction (excluding procedure-related events), stroke, and hospitalization for unstable angina.
Secondary outcomes were the time to the first occurrence of each individual component of the primary outcome, the time to death from any cause, and the change from baseline in LDL and HDL cholesterol levels. Tertiary outcomes included further breakdowns in categories and composites of secondary outcomes.
Members of a central committee who were unaware of study-group assignments adjudicated potential outcomes as reported by the investigators. Adjudicated outcomes are not included in totals of adverse events and serious adverse events.
Statistical Analysis
The original design assumed a sample size of 13,000 patients (6500 per treatment group) to yield 551 primary outcomes in the atorvastatin-only group (8.48%) and 433 in the group receiving both atorvastatin and torcetrapib (6.66%) after an average of 4.5 years of follow-up — in other words, an absolute reduction of 1.82 percentage points or a relative reduction of 21% in the cumulative incidence. This number of patients would provide a statistical power of 90% to detect a treatment difference in the primary efficacy analysis at the two-sided level of 0.05 with the use of a log-rank test. A total of 15,067 patients underwent randomization, with overenrollment owing to an increase in screening activity after notification of an upcoming closure in enrollment at each site. On the basis of the modified primary outcome in the amended protocol and on the increased number of patients, the number of primary outcomes at an average follow-up of 4.5 years was expected to be 1820.
The prespecified safety-monitoring boundary (a P value <0.01, unadjusted for multiple comparisons) was based on a log-rank test for death from any cause. An efficacy-monitoring boundary (to be implemented after approximately 50% of the expected number of events had occurred in the primary outcome) was prespecified, but the requisite event count was never reached.
All treatment comparisons were performed with the use of an intention-to-treat analysis. All data were censored for the primary analyses on December 2, 2006, when the trial was terminated. Events occurring after that date, in the period between termination of the study and the end of data collection, are also reported. These events were captured either at a final visit after the discontinuation of a study drug (active surveillance) or as a result of instructions to patients to report serious adverse events (passive surveillance). The last adjudicated outcome reported during this observation period occurred on July 15, 2007.
P values for continuous and ordered categorical data were computed with the use of a nonparametric Wilcoxon test. Pearson's chi-square test (without continuity correction) was used for dichotomous and unordered categorical data. The log-rank test was used for time-to-event analyses. Post hoc exploratory analyses were also performed; only descriptive statistics were used to identify patterns of association, since these analyses were not inferential in nature. No adjustments have been made for multiple comparisons.
Results
Patients
Between August 23, 2004, and December 28, 2005, a total of 15,067 patients underwent randomization at 260 centers in seven countries. Of these patients, 7534 were assigned to receive atorvastatin plus placebo (atorvastatin-only group), and 7533 were assigned to receive torcetrapib plus atorvastatin (torcetrapib group) (Figure 1). At the end of the study on December 2, 2006, the median follow-up in each group was 550 days. Earlier discontinuation of treatment had occurred in 831 patients in the atorvastatin-only group (11.0%) and in 1008 patients in the torcetrapib group (13.4%). Higher rates of discontinuation owing to nonfatal adverse events in the torcetrapib group were associated mainly with a higher frequency of hypertension, nonspecific gastrointestinal symptoms, and headache. Follow-up was 99.7% complete, with 20 patients in the atorvastatin-only group and 19 patients in the torcetrapib group who were not followed until December 2, 2006. Baseline demographic and clinical characteristics of the two groups are presented in Table 1. Patients with a history of diabetes but no evidence of cardiovascular disease at study entry represented 18.8% of the atorvastatin-only group and 17.9% of the torcetrapib group (data not shown).

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The "Bad Bug Book"

2007-11-25T03:03:00.000+07:00

This handbook provides basic facts regarding foodborne pathogenic microorganisms and natural toxins. It brings together in one place information from the Food & Drug Administration, the Centers for Disease Control & Prevention, the USDA Food Safety Inspection Service, and the National Institutes of Health.
Some technical terms have been linked to the National Library of Medicine's Entrez glossary. Recent articles from Morbidity and Mortality Weekly Reports have been added to selected chapters to update the handbook with information on later outbreaks or incidents of foodborne disease. At the end of selected chapters on pathogenic microorganisms, hypertext links are included to relevant Entrez abstracts and GenBank genetic loci. A more complete description of the handbook may be found in the Preface.

PATHOGENIC BACTERIA
Salmonella spp.
Clostridium botulinum
Staphylococcus aureus
Campylobacter jejuni
Yersinia enterocolitica and Yersinia pseudotuberculosis
Listeria monocytogenes
Vibrio cholerae O1
Vibrio cholerae non-O1
Vibrio parahaemolyticus and other vibrios
Vibrio vulnificus
Clostridium perfringens
Bacillus cereus
Aeromonas hydrophila and other spp.
Plesiomonas shigelloides
Shigella spp.
Miscellaneous enterics
Streptococcus
ENTEROVIRULENT ESCHERICHIA COLI GROUP (EEC Group)
Escherichia coli - enterotoxigenic (ETEC)
Escherichia coli - enteropathogenic (EPEC)
Escherichia coli O157:H7 enterohemorrhagic (EHEC)
Escherichia coli - enteroinvasive (EIEC)
PARASITIC PROTOZOA and WORMS
Giardia lamblia
Entamoeba histolytica
Cryptosporidium parvum
Cyclospora cayetanensis
Anisakis sp. and related worms
Diphyllobothrium spp.
Nanophyetus spp.
Eustrongylides sp.
Acanthamoeba and other free-living amoebae
Ascaris lumbricoides and Trichuris trichiura
VIRUSES
Hepatitis A virus
Hepatitis E virus
Rotavirus
Norwalk virus group
Other viral agents
NATURAL TOXINS
Ciguatera poisoning
Shellfish toxins (PSP, DSP, NSP, ASP)
Scombroid poisoning
Tetrodotoxin (Pufferfish)
Mushroom toxins
Aflatoxins
Pyrrolizidine alkaloids
Phytohaemagglutinin (Red kidney bean poisoning)
Grayanotoxin (Honey intoxication)
OTHER PATHOGENIC AGENTS
Prions
APPENDICES
Infective dose
Epidemiology summary table
Factors affecting microbial growth in foods
Foodborne Disease Outbreaks, United States 1988-1992
Additional Foodborne Disease Outbreak Articles and Databases.

Free Full Text

2007-11-23T23:48:00.000+07:00

FreeFullText.com adalah wesite yang mengumpulkan berbagai macam alamat jurnal ilmiah yang bisa diakses secara gratis. Alamat jurnal-jurnal tersebut tersusun berdasarkan alphabetic, jadi bisa mempremudah kita dalam mencari jurnal yang kita inginkan. Silahkan buktikan sendiri di link ini http://www.freefulltext.com/

Artikel-artikel Biologi Molekuler

2007-11-02T00:23:00.000+07:00

Jurnal ini memuat berbagai informasi hasil penelitian terbaru di bidang biologi molekuler, untuk edisi 1 November 2007 sendiri ada beberapa isu terberu di bidang tersebut. Sayangnya jurnal ini The EMBO Journal tidak gratis, so cuma bisa membaca Abstraknya aja. Tapi untuk sekedar pengetahuan sudah cukup bagus...

Isu-isu terbaru 1 November 2007 antara lain :

Multifunctional class I transcription in Trypanosoma brucei depends on a novel protein complex

Jens Brandenburg, Bernd Schimanski, Everson Nogoceke, Tu N Nguyen, Júlio C Padovan, Brian T Chait, George A M Cross and Arthur Günzl The EMBO Journal advance online publication 1 November 2007;doi: 10.1038/sj.emboj.7601905

Abstrak

The vector-borne, protistan parasite Trypanosoma brucei is the only known eukaryote with a multifunctional RNA polymerase I that, in addition to ribosomal genes, transcribes genes encoding the parasite's major cell-surface proteins—the variant surface glycoprotein (VSG) and procyclin. In the mammalian bloodstream, antigenic variation of the VSG coat is the parasite's means to evade the immune response, while procyclin is necessary for effective establishment of trypanosome infection in the fly. Moreover, the exceptionally high efficiency of mono-allelic VSG expression is essential to bloodstream trypanosomes since its silencing caused rapid cell-cycle arrest in vitro and clearance of parasites from infected mice. Here we describe a novel protein complex that recognizes class I promoters and is indispensable for class I transcription; it consists of a dynein light chain and six polypeptides that are conserved only among trypanosomatid parasites. In accordance with an essential transcriptional function of the complex, silencing the expression of a key subunit was lethal to bloodstream trypanosomes and specifically affected the abundance of rRNA and VSG mRNA. The complex was dubbed class I transcription factor A.

Keywords: class I transcription factor, DYNLL1, procyclin, Tryponosoma brucei, VSG

A role for cytochrome c and cytochrome c peroxidase in electron shuttling from Erv1

Deepa V Dabir1, 6, Edward P Leverich1, 6, Sung-Kun Kim2, 5, Frederick D Tsai1, Masakazu Hirasawa2, David B Knaff2 and Carla M Koehler1, 3, 4 1 Department of Chemistry and Biochemistry, University of California at Los Angeles, Los Angeles, CA, USA2 Department of Chemistry and Biochemistry, Center for Biotechnology and Genomics, Texas Tech University, Lubbock, TX, USA3 Molecular Biology Institute, University of California at Los Angeles, Los Angeles, CA, USA4 Jonsson Comprehensive Cancer Center, University of California at Los Angeles, Los Angeles, CA, USA5 Department of Chemistry and Biochemistry, Baylor University, Waco, TX, USATo whom correspondence should be addressedCarla M Koehler, Department of Chemistry and Biochemistry, Molecular Biology Institute, Jonsson Comprehensive Cancer Center, Box 951569, University of California at Los Angeles, Los Angeles, CA 90095, USA. Tel.: +1 310 794 4834; Fax: +1 310 206 4038; E-mail: koehlerc@chem.ucla.edu

Abstrak

Erv1 is a flavin-dependent sulfhydryl oxidase in the mitochondrial intermembrane space (IMS) that functions in the import of cysteine-rich proteins. Redox titrations of recombinant Erv1 showed that it contains three distinct couples with midpoint potentials of -320, -215, and -150 mV. Like all redox-active enzymes, Erv1 requires one or more electron acceptors. We have generated strains with erv1 conditional alleles and employed biochemical and genetic strategies to facilitate identifying redox pathways involving Erv1. Here, we report that Erv1 forms a 1:1 complex with cytochrome c and a reduced Erv1 can transfer electrons directly to the ferric form of the cytochrome. Erv1 also utilized molecular oxygen as an electron acceptor to generate hydrogen peroxide, which is subsequently reduced to water by cytochrome c peroxidase (Ccp1). Oxidized Ccp1 was in turn reduced by the Erv1-reduced cytochrome c. By coupling these pathways, cytochrome c and Ccp1 function efficiently as Erv1-dependent electron acceptors. Thus, we propose that Erv1 utilizes diverse pathways for electron shuttling in the IMS.

Keywords: mitochondria, protein import, protein translocation, redox chemistry

Source : http://www.nature.com/emboj/index.html

Semoga bermanfaa ....

Balasan buat mas wayan

2007-11-02T00:00:00.000+07:00

Salam kenal juga buat Mas Wayan.

Sebenarnya untuk memberi ide Mas Wayan, aku belum mampu. Coz basic keilmuanku bukan management. Tapi untuk sekedar berbagi informasi, mungkin bisa....

Ada beberapa artikel yang cukup bagus yang membahas " Manajemen Proyek". Smoga saja artikel-artikel ini bisa bermanfaat buat mas wayan.

Artike-artikel ini saya peroleh dari Websitenya Drs. Azhari, SN., MT. Beliau adalah staff pengajar Universitas Gadjah Mada Yogyakarta. Mas Wayan kunjungi aja websitnya di http://arisn.staff.ugm.ac.id/index.php?option=com_tugas&task=listUploadedTugas&id=11 di situ banyak artike-artikel yang membahas Manajemen Proyek.

Dah yo... semoga sukses.

Artikel - artikel terbaru dari INTERNATIONAL JOURNAL OF OBESITY

2007-10-30T19:33:00.000+07:00

Yang ini adalah artikel-artikel terbaru dari INTERNATIONAL JOURNAL OF OBESITY November 2007 Volume 31 Number 11, pp 1629 - 1762 .

Special Web Collection: Diabetes and Hypertension

The treatment of these conditions has become one of the greatest
challenges for medical professionals today. Here, Nature Clinical
Practice presents a relevant selection of articles from a variety
of Nature Publishing Group journals.

To access, go to
http://ealerts.nature.com/cgi-bin24/DM/y/ehDC0XM6Hf0Hir0Bcsg0EH

Available online until December 31st 2007.

----------------------
REVIEWS
----------------------
Obesity and polymorphisms in genes regulating human adipose tissue
I Dahlman and P Arner
Abstract: http://ealerts.nature.com/cgi-bin24/DM/y/ehDC0XM6Hf0Hir0BfbT0Ei
Article: http://ealerts.nature.com/cgi-bin24/DM/y/ehDC0XM6Hf0Hir0BfbU0Ej

The association of pregnancy and the development of obesity - results
of a systematic review and meta-analysis on the natural history of
postpartum weight retention
N M Schmitt, W K Nicholson and J Schmitt
Abstract: http://ealerts.nature.com/cgi-bin24/DM/y/ehDC0XM6Hf0Hir0BfbV0Ek
Article: http://ealerts.nature.com/cgi-bin24/DM/y/ehDC0XM6Hf0Hir0BfbW0El

----------------------
ORIGINAL ARTICLES
----------------------
Enhanced vascular contractility and diminished coronary artery flow in
rats made hypertensive from diet-induced obesity
C M Boustany-Kari, M Gong, W S Akers, Z Guo and L A Cassis
Abstract: http://ealerts.nature.com/cgi-bin24/DM/y/ehDC0XM6Hf0Hir0BfbX0Em
Article: http://ealerts.nature.com/cgi-bin24/DM/y/ehDC0XM6Hf0Hir0BfbY0En

Metabolic action of peroxisome proliferator-activated receptor [gamma]
agonism in rats with exogenous hypercorticosteronemia
M Berthiaume, M Laplante, A Tchernof and Y Deshaies
Abstract: http://ealerts.nature.com/cgi-bin24/DM/y/ehDC0XM6Hf0Hir0BfbZ0Eo
Article: http://ealerts.nature.com/cgi-bin24/DM/y/ehDC0XM6Hf0Hir0Bfba0Ev

Human visceral adipose tissue and the plasminogen activator inhibitor
type 1
J H N Lindeman, H Pijl, K Toet, P H C Eilers, B van Ramshorst, M M
Buijs, J H van Bockel and T Kooistra
Abstract: http://ealerts.nature.com/cgi-bin24/DM/y/ehDC0XM6Hf0Hir0Bfbb0Ew
Article: http://ealerts.nature.com/cgi-bin24/DM/y/ehDC0XM6Hf0Hir0Bfbc0Ex

The association between weight history and physical performance in the
Health, Aging and Body Composition study
D K Houston, J Ding, B J Nicklas, T B Harris, J S Lee, M C Nevitt, S M
Rubin, F A Tylavsky and S B Kritchevsky
Abstract: http://ealerts.nature.com/cgi-bin24/DM/y/ehDC0XM6Hf0Hir0Bfbd0Ey
Article: http://ealerts.nature.com/cgi-bin24/DM/y/ehDC0XM6Hf0Hir0Bfbe0Ez

Effects of food form on appetite and energy intake in lean and obese
young adults
D M Mourao, J Bressan, W W Campbell and R D Mattes
Abstract: http://ealerts.nature.com/cgi-bin24/DM/y/ehDC0XM6Hf0Hir0Bfbf0E1
Article: http://ealerts.nature.com/cgi-bin24/DM/y/ehDC0XM6Hf0Hir0Bfbg0E2

Appetite hormones and energy intake in obese men after consumption of
fructose, glucose and whey protein beverages
J Bowen, M Noakes and P M Clifton
Abstract: http://ealerts.nature.com/cgi-bin24/DM/y/ehDC0XM6Hf0Hir0Bfbh0E3
Article: http://ealerts.nature.com/cgi-bin24/DM/y/ehDC0XM6Hf0Hir0Bfbi0E4

An intervention study of the effects of calcium intake on faecal fat
excretion, energy metabolism and adipose tissue mRNA expression of
lipid-metabolism related proteins
N Boon, G B J Hul, J H C H Stegen, W E M Sluijsmans, C Valle, D
Langin, N Viguerie and W H M Saris
Abstract: http://ealerts.nature.com/cgi-bin24/DM/y/ehDC0XM6Hf0Hir0Bfbj0E5
Article: http://ealerts.nature.com/cgi-bin24/DM/y/ehDC0XM6Hf0Hir0Bfbk0E6

Sleep-related disturbances and physical inactivity are independently
associated with obesity in adults
M Fogelholm, E Kronholm, K Kukkonen-Harjula, T Partonen, M Partinen
and M Harma
Abstract: http://ealerts.nature.com/cgi-bin24/DM/y/ehDC0XM6Hf0Hir0Bfbl0E7
Article: http://ealerts.nature.com/cgi-bin24/DM/y/ehDC0XM6Hf0Hir0Bfbm0E8

Night eating syndrome and nocturnal snacking: association with
obesity, binge eating and psychological distress
S L Colles, J B Dixon and P E O'Brien
Abstract: http://ealerts.nature.com/cgi-bin24/DM/y/ehDC0XM6Hf0Hir0Bfbn0EA
Article: http://ealerts.nature.com/cgi-bin24/DM/y/ehDC0XM6Hf0Hir0Bfbo0EB

Defined weight expectations in overweight women: anthropometrical,
psychological and eating behavioral correlates
V Provencher, C Begin, M-P Gagnon-Girouard, H C Gagnon, A Tremblay, S
Boivin and S Lemieux
Abstract: http://ealerts.nature.com/cgi-bin24/DM/y/ehDC0XM6Hf0Hir0Bfbp0EC
Article: http://ealerts.nature.com/cgi-bin24/DM/y/ehDC0XM6Hf0Hir0Bfbq0ED

The role of patients' expectations and goals in the behavioral and
pharmacological treatment of obesity
A N Fabricatore, T A Wadden, L G Womble, D B Sarwer, R I Berkowitz, G
D Foster and J R Brock
Abstract: http://ealerts.nature.com/cgi-bin24/DM/y/ehDC0XM6Hf0Hir0Bfbs0EF
Article: http://ealerts.nature.com/cgi-bin24/DM/y/ehDC0XM6Hf0Hir0Bfbu0EH

UCP2 A55V variant is associated with obesity and related phenotypes in
an aboriginal community in Taiwan
T N Wang, M C Huang, H L Lin, C H Hsiang, A M J Ko, W T Chang and Y C
Ko
Abstract: http://ealerts.nature.com/cgi-bin24/DM/y/ehDC0XM6Hf0Hir0Bfbw0EJ
Article: http://ealerts.nature.com/cgi-bin24/DM/y/ehDC0XM6Hf0Hir0Bfby0EL

----------------------
SHORT COMMUNICATIONS
----------------------
INSIG2 gene polymorphism is not associated with obesity in Caucasian,
Afro-Caribbean and Indian subjects
A J P Smith, J A Cooper, L K Li and S E Humphries
Abstract: http://ealerts.nature.com/cgi-bin24/DM/y/ehDC0XM6Hf0Hir0Bfb20EA
Article: http://ealerts.nature.com/cgi-bin24/DM/y/ehDC0XM6Hf0Hir0Bfb50ED

Weight loss during chronic, cervical vagus nerve stimulation in
depressed patients with obesity: an observation
J V Pardo, S A Sheikh, M A Kuskowski, C Surerus-Johnson, M C Hagen, J
T Lee, B R Rittberg and D E Adson
Abstract: http://ealerts.nature.com/cgi-bin24/DM/y/ehDC0XM6Hf0Hir0Bfb80EG
Article: http://ealerts.nature.com/cgi-bin24/DM/y/ehDC0XM6Hf0Hir0BfcB0ER

----------------------
LETTERS TO THE EDITOR
----------------------
Metabolic syndrome definition in children: a focus on the different
stages of growth
M F Rolland-Cachera, S Peneau and F Bellisle
http://ealerts.nature.com/cgi-bin24/DM/y/ehDC0XM6Hf0Hir0BfcE0EU

Abnormal body mass index trajectories in childhood and possible health
consequences
P Brambilla and A Pietrobelli
http://ealerts.nature.com/cgi-bin24/DM/y/ehDC0XM6Hf0Hir0BfcH0EX

------------------------------

------------------------------------
Science news from a different angle

From daily science updates to investigative journalism, from community
comments to editorial opinions, Nature brings you the most in-depth
science news coverage from the most influential scientific journal in
the world. Visit Nature News online today.

Nature News http://ealerts.nature.com/cgi-bin24/DM/y/ehDC0XM6Hf0Hir0PLo0EL

Source : International_Journal_of_Obesity@ealerts.nature.com

Penelitian terbaru dari British Dental Journal

2007-10-30T19:25:00.000+07:00

Kemaren aku dapat informasi penelitian terbari dari British Dental Journal. Ga cuma itu, tapi banyak inormasi terbaru yang disertakan. Semoga semua informasi ini bisa bermanfaat.

October 2007 Volume 203 Number 8, pp 439 - 493

Visit BDJ online to browse the journal.

Now available at http://ealerts.nature.com/cgi-bin24/DM/y/ehA60XM6Hf0Hhe0BK4g0EK

Please note that you need to be a subscriber to enjoy full text access
to BDJ online. To purchase a subscription, please visit:
http://ealerts.nature.com/cgi-bin24/DM/y/ehA60XM6Hf0Hhe0BHqL0Ep

Alternatively, to recommend a subscription to your library, please visit
http://ealerts.nature.com/cgi-bin24/DM/y/ehA60XM6Hf0Hhe0BRQi0Ew

==============================

=======================================

Ensure regular access to the BDJ at your library

Click here for details:
http://ealerts.nature.com/cgi-bin24/DM/y/ehA60XM6Hf0Hhe0BHqM0Eq

=====================================================================

----------------------
RESEARCH
----------------------
Verifiable CPD Paper
Sterilisation of re-usable instruments in general dental practice E16
A. J. Smith, J. Bagg, D. Hurrell and S. McHugh
doi:10.1038/bdj.2007.912
Abstract: http://ealerts.nature.com/cgi-bin24/DM/y/ehA60XM6Hf0Hhe0BfY l0ET
Article: http://ealerts.nature.com/cgi-bin24/DM/y/ehA60XM6Hf0Hhe0BfYm0EU

The teaching of removable partial dentures in Ireland and the United Kingdom E17
C. D. Lynch and P. F. Allen
doi:10.1038/bdj.2007.581
Abstract: http://ealerts.nature.com/cgi-bin24/DM/y/ehA60XM6Hf0Hhe0BfYn0EV
Article: http://ealerts.nature.com/cgi-bin24/DM/y/ehA60XM6Hf0Hhe0BfYo0EW

What are the occlusal outcomes for unilateral cleft lip and palate
patients? A national project in the UK E18
S. Deacon, P. Bessant, J. I. Russell and I. Hathorn
doi:10.1038/bdj.2007.807
Abstract: http://ealerts.nature.com/cgi-bin24/DM/y/ehA60XM6Hf0Hhe0BfYp0EX
Article: http://ealerts.nature.com/cgi-bin24/DM/y/ehA60XM6Hf0Hhe0BfYq0EY

----------------------
OPINION
----------------------
EDITORIAL
Blood-borne one year on p439
doi:10.1038/bdj.2007.963
http://ealerts.nature.com/cgi-bin24/DM/y/ehA60XM6Hf0Hhe0BfUv0EZ

----------------------
VIEW POINTS
----------------------
LETTERS
Standard protocols p440
G. Kini
doi:10.1038/bdj.2007.955
http://ealerts.nature.com/cgi-bin24/DM/y/ehA60XM6Hf0Hhe0BfUw0Ea

Source of concern pp440 - 441
N. J. Knott
doi:10.1038/bdj.2007.956
http://ealerts.nature.com/cgi-bin24/DM/y/ehA60XM6Hf0Hhe0BfUx0Eb

Hookah hazards p441
Meghashyam Bhat
doi:10.1038/bdj.2007.957
http://ealerts.nature.com/cgi-bin24/DM/y/ehA60XM6Hf0Hhe0BfUy0Ec

Gammon's Law pp441 - 442
M. Bishop
doi:10.1038/bdj.2007.958
http://ealerts.nature.com/cgi-bin24/DM/y/ehA60XM6Hf0Hhe0BfUz0Ed

Poor policy decisions p442
S. Shah
doi:10.1038/bdj.2007.959
http://ealerts.nature.com/cgi-bin24/DM/y/ehA60XM6Hf0Hhe0BfU10EQ

Unnecessary extractions p442
A. J. Larner
doi:10.1038/bdj.2007.960
http://ealerts.nature.com/cgi-bin24/DM/y/ehA60XM6Hf0Hhe0BfU20ER

----------------------
NEWS
----------------------
A step closer to mouth cancer drug availability p443
doi:10.1038/bdj.2007.967
http://ealerts.nature.com/cgi-bin24/DM/y/ehA60XM6Hf0Hhe0BfU30ES

Fluoride protection discussed in China conference p443
doi:10.1038/bdj.2007.968
http://ealerts.nature.com/cgi-bin24/DM/y/ehA60XM6Hf0Hhe0BfU40ET

50th reunion for dental class p443
doi:10.1038/bdj.2007.969
http://ealerts.nature.com/cgi-bin24/DM/y/ehA60XM6Hf0Hhe0BfU50EU

New Dean for Sheffield p444
doi:10.1038/bdj.2007.970
http://ealerts.nature.com/cgi-bin24/DM/y/ehA60XM6Hf0Hhe0BfU60EV

GDC fees for 2008 p444
doi:10.1038/bdj.2007.971
http://ealerts.nature.com/cgi-bin24/DM/y/ehA60XM6Hf0Hhe0BfU70EW

Death notice p444
doi:10.1038/bdj.2007.972
http://ealerts.nature.com/cgi-bin24/DM/y/ehA60XM6Hf0Hhe0BfU80EX

Tooth whitening investigation uncovers illegal treatments p444
doi:10.1038/bdj.2007.973
http://ealerts.nature.com/cgi-bin24/DM/y/ehA60XM6Hf0Hhe0BfVA0Eh

Resignation p444
doi:10.1038/bdj.2007.993
http://ealerts.nature.com/cgi-bin24/DM/y/ehA60XM6Hf0Hhe0BfVB0Ei

UK's first new dental school for 40 years opens p445
doi:10.1038/bdj.2007.974
http://ealerts.nature.com/cgi-bin24/DM/y/ehA60XM6Hf0Hhe0BfVC0Ej

Spicy painkilling alternative p446
doi:10.1038/bdj.2007.975
http://ealerts.nature.com/cgi-bin24/DM/y/ehA60XM6Hf0Hhe0BfVD0Ek

Cash injection for decontamination p446
doi:10.1038/bdj.2007.976
http://ealerts.nature.com/cgi-bin24/DM/y/ehA60XM6Hf0Hhe0BfVE0El

Dental work can boost self-esteem p447
doi:10.1038/bdj.2007.977
http://ealerts.nature.com/cgi-bin24/DM/y/ehA60XM6Hf0Hhe0BfVF0Em

Snake venom used in oral surgery for faster healing p447
doi:10.1038/bdj.2007.978
http://ealerts.nature.com/cgi-bin24/DM/y/ehA60XM6Hf0Hhe0BfVG0En

Diary p447
doi:10.1038/bdj.2007.979
http://ealerts.nature.com/cgi-bin24/DM/y/ehA60XM6Hf0Hhe0BfVH0Eo

----------------------
OPINION
----------------------
To screen, or not to screen, - that is the question:- pp449 - 451
R. A. Baker
doi:10.1038/bdj.2007.945
Abstract: http://ealerts.nature.com/cgi-bin24/DM/y/ehA60XM6Hf0Hhe0BfVI0Ep
Article: http://ealerts.nature.com/cgi-bin24/DM/y/ehA60XM6Hf0Hhe0BfVJ0Eq

Improving oral health with the new dental contract pp453 - 455
W. Richards and A. Toy
doi:10.1038/bdj.2007.946
Abstract: http://ealerts.nature.com/cgi-bin24/DM/y/ehA60XM6Hf0Hhe0BfVK0Er
Article: http://ealerts.nature.com/cgi-bin24/DM/y/ehA60XM6Hf0Hhe0BfVL0Es

----------------------
PRACTICE
----------------------
Verifiable CPD Paper
Combined CPP-ACP and photoactivated disinfection (PAD) therapy in
arresting root surface caries: a case report pp457 - 459
J. Vlacic, I. A. Meyers and L. J. Walsh
doi:10.1038/bdj.2007.947
Abstract: http://ealerts.nature.com/cgi-bin24/DM/y/ehA60XM6Hf0Hhe0BfVM0Et
Article: http://ealerts.nature.com/cgi-bin24/DM/y/ehA60XM6Hf0Hhe0BfVN0Eu

A review of the aetiology and management of fractured dental implants
and a case report pp461 - 466
P. Virdee and K. Bishop
doi:10.1038/bdj.2007.948
Abstract: http://ealerts.nature.com/cgi-bin24/DM/y/ehA60XM6Hf0Hhe0BfVO0Ev
Article: http://ealerts.nature.com/cgi-bin24/DM/y/ehA60XM6Hf0Hhe0BfVP0Ew

----------------------
SUMMARIES
----------------------
ABSTRACTS
Dental enamel defects in children with coeliac disease p467
doi:10.1038/bdj.2007.951
Abstract: http://ealerts.nature.com/cgi-bin24/DM/y/ehA60XM6Hf0Hhe0BfVQ0Ex
Article: http://ealerts.nature.com/cgi-bin24/DM/y/ehA60XM6Hf0Hhe0BfVR0Ey

Complications encountered in a prospective series of 182 patients treated
surgically for mouth cancer p467
doi:10.1038/bdj.2007.952
Abstract: http://ealerts.nature.com/cgi-bin24/DM/y/ehA60XM6Hf0Hhe0BfVS0Ez
Article: http://ealerts.nature.com/cgi-bin24/DM/y/ehA60XM6Hf0Hhe0BfVT0E1

Treatment history of teeth in relation to the longevity of the teeth and
their restorations: outcomes of teeth treated and maintained for 15 years p467
doi:10.1038/bdj.2007.953
Abstract: http://ealerts.nature.com/cgi-bin24/DM/y/ehA60XM6Hf0Hhe0BfVU0E2
Article: http://ealerts.nature.com/cgi-bin24/DM/y/ehA60XM6Hf0Hhe0BfVV0E3

Oral prostheses and oral health-related quality of life: a survey study
of an adult Swedish population p467
doi:10.1038/bdj.2007.954
Abstract: http://ealerts.nature.com/cgi-bin24/DM/y/ehA60XM6Hf0Hhe0BfVW0E4
Article: http://ealerts.nature.com/cgi-bin24/DM/y/ehA60XM6Hf0Hhe0BfVX0E5

RESEARCH SUMMARY
Use of benchtop steam sterilisers pp468 - 469
doi:10.1038/bdj.2007.966
Abstract: http://ealerts.nature.com/cgi-bin24/DM/y/ehA60XM6Hf0Hhe0BfVY0E6
Article: http://ealerts.nature.com/cgi-bin24/DM/y/ehA60XM6Hf0Hhe0BfVZ0E7

RPD teaching in the UK and Ireland pp470 - 471
doi:10.1038/bdj.2007.992
Abstract: http://ealerts.nature.com/cgi-bin24/DM/y/ehA60XM6Hf0Hhe0BfVa0EF
Article: http://ealerts.nature.com/cgi -bin24/DM/y/ehA60XM6Hf0Hhe0BfVb0EG

----------------------
EDUCATION
----------------------
Going interactive: six strategies to meet the challenge of teaching
Electrosurgery to general dental practitioners pp473 - 477
B. R. Davies, B. J. Millar and C. Louca
doi:10.1038/bdj.2007.949
Abstract: http://ealerts.nature.com/cgi-bin24/DM/y/ehA60XM6Hf0Hhe0BfVc0EH
Article: http://ealerts.nature.com/cgi-bin24/DM/y/ehA60XM6Hf0Hhe0BfVd0EI

----------------------
GENERAL
----------------------
The Bagenal letters pp479 - 483
M. Bishop
doi:10.1038/bdj.2007.950
Abstract: http://ealerts.nature.com/cgi-bin24/DM/y/ehA60XM6Hf0Hhe0BfVe0EJ
Article: http://ealerts.nature.com/cgi-bin24/DM/y/ehA60XM6Hf0Hhe0BfVf0EK

----------------------
TRADE NEWS
----------------------
WHAT'S NEW
Digital imaging solutions p489
doi:10.1038/bdj.2007.980
http://ealerts.nature.com/cgi-bin24/DM/y/ehA60XM6Hf0Hhe0BfVg0EL

Extra protection for patients' teeth p489
doi:10.1038/bdj.2007.981
http://ealerts.nature.com/cgi-bin24/DM/y/ehA60XM6Hf0Hhe0BfVh0EM

Easy peel and seal p489
doi:10.1038/bdj.2007.982
http://ealerts.nature.com/cgi-bin24/DM/y/ehA60XM6Hf0Hhe0BfVi0EN

Faster crown removal p489
doi:10.1038/bdj.2007.983
http://ealerts.nature.com/cgi-bin24/DM/y/ehA60XM6Hf0Hhe0BfVj0EO

Straight picture of jaw surgery p489
doi:10.1038/bdj.2007.984
http://ealerts.nature.com/cgi-bin24/DM/y/ehA60XM6Hf0Hhe0BfVk0EP

TRADE NEWS FOCUS
Cleaning to the cellular level p490
doi:10.1038/bdj.2007.985
http://ealerts.nature.com/cgi-bin24/DM/y/ehA60XM6Hf0Hhe0BfVl0EQ

Cleaning to the cellular level p490
doi:10.1038/bdj.2007.986
http://ealerts.nature.com/cgi-bin24/DM/y/ehA60XM6Hf0Hhe0BfVm0ER

Anti-bacterial glass launched p490
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Defective ubiquitinylation of EGFR mutants of lung cancer confers prolonged signaling

2007-10-26T18:32:00.000+07:00

Oncogene (2007) 26, 6968–6978; doi:10.1038/sj.onc.1210503; published online 7 May 2007

K Shtiegman¹, B S Kochupurakkal¹, Y Zwang¹, G Pines¹, A Starr², A Vexler², A Citri¹, M Katz¹, S Lavi¹, Y Ben-Basat¹, S Benjamin³, S Corso⁴, J Gan¹, R B Yosef², S Giordano⁴ and Y Yarden¹

¹Department of Biological Regulation, The Weizmann Institute of Science, Rehovot, Israel
²Division of Oncology, Tel Aviv Sourasky Medical Center and Tel Aviv University School of Medicine, Ramat Aviv, Israel
³Department of Cell Research and Immunology, Tel Aviv University, Ramat Aviv, Israel
⁴Division of Molecular Oncology, Department of Oncological Sciences, Institute for Cancer Research and Treatment, University of Torino School of Medicine, Candiolo, Torino, Italy

Correspondence: Professor Y Yarden, Department of Biological Regulation, Room 302, Candiotty Building, The Weizmann Institute of Science, 1 Hertzl Street, Rehovot 76100, Israel. E-mail: yosef.yarden@weizmann.ac.il

Received 12 October 2006; Revised 12 March 2007; Accepted 23 March 2007; Published online 7 May 2007.

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Abstract

Several distinct mutations within the kinase domain of the epidermal growth factor receptor (EGFR) are associated with non-small cell lung cancer, but mechanisms underlying their oncogenic potential are incompletely understood. Although normally ligand-induced kinase activation targets EGFR to Cbl-mediated receptor ubiquitinylation and subsequent degradation in lysosomes, we report that certain EGFR mutants escape this regulation. Defective endocytosis characterizes a deletion mutant of EGFR, as well as a point mutant (L858R-EGFR), whose association with c-Cbl and ubiquitinylation are impaired. Our data raise the possibility that refractoriness of L858R-EGFR to downregulation is due to enhanced heterodimerization with the oncogene product HER2, which leads to persistent stimulation.

Keywords:

endocytosis, Gefitinib, growth factor, NSCLC, tyrosine kinase

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Introduction

Excessive epidermal growth factor (EGF) signaling due to genetic aberrations is richly implicated in human cancer (Hynes et al., 2001; Yarden and Sliwkowski, 2001). To generate intracellular signals, EGF receptor (EGFR) must homodimerize or heterodimerize with members of its family, primarily a ligand-less oncogenic receptor called HER2/ErbB-2. These receptors promote cellular activation by recruiting several pathways, including the mitogen-activated protein kinase (MAPK) and the phosphoinositide 3-kinase – protein kinase B (PI3K-PKB/Akt) pathway. Following stimulation, EGFR undergoes ubiquitinylation by an E3 ubiquitin ligase, c-Cbl, which sorts hyper-phosphorylated receptors to degradation in lysosomes (reviewed in Dikic and Giordano, 2003).

Several groups reported in 2004 that certain heterozygous, somatically acquired EGFR mutations in lung cancer predict significant clinical responses to kinase inhibitors specific to EGFR (Lynch et al., 2004; Paez et al., 2004; Pao et al., 2004). All mutations are restricted to the tyrosine kinase domain of EGFR. The most frequent point mutation is a substitution of an arginine for leucine at position 858 (L858R). Yet other mutants carry in-frame short deletions. A second mutation, T790M, has been associated with acquisition of secondary resistance of patients to kinase inhibitors (Kobayashi et al., 2005; Pao et al., 2005). Differential patterns of autophosphorylation, resulting in superior Akt and Stat signaling, have been associated with EGFR mutants, which explains how kinase inhibitors selectively induce apoptosis of mutant-expressing cells (Sordella et al., 2004; Tracy et al., 2004). Along with pathway-selective activation by EGFR mutants, their ligand-induced autophosphorylation decays relatively slowly (Lynch et al., 2004), suggesting that persistent stimulation contributes to cell transformation. To examine this model and resolve the underlying mechanism, we tested mutant EGFRs in lung cancer cells and in ectopic systems. Our data indicate that ligand-induced inactivation of L858R, 746-50 and the double-mutant L858R/T790M, is defective. The defect may be due to a propensity of the mutants to heterodimerize with HER2, thereby evading c-Cbl-mediated ubiquitinylation and subsequent sorting to degradation in lysosomes. Hence, our studies raise the possibility that HER2 collaborates with EGFR mutants of lung cancer.

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Results

Downregulation of EGFR mutants is impaired when examined in transfected cells

We constructed six of the previously identified EGFR mutations (Lynch et al., 2004; Paez et al., 2004) in a mammalian expression vector. These include G719C and G719S, L858R, L861Q, 746-50 and 747-53S. Chinese hamster ovary (CHO) cells that express no endogenous EGFR were transfected with plasmids encoding either WT-EGFR or the respective mutant. By using a surface biotinylation assay, which labels surface-exposed, rather than intracellular proteins, we determined that all mutants reached the cell surface (Figure 1a). Furthermore, all mutants retained activation by EGF when assayed with anti-phosphotyrosine antibodies (data not shown). It has been reported that L858R, 747-53S and 746-50 exhibit enhanced activation of downstream effectors such as signal transduction and activators of transcription (Stat proteins) (Sordella et al., 2004). Indeed, Stat3 activation was significantly increased, both basally and in response to EGF, in CHO cells transfected with plasmids encoding for L858R and L861Q (Figure 1b).

Figure 1.

Downregulation of epidermal growth factor receptor (EGFR) mutants is impaired when examined in transfected cells. (a) The surface of Chinese hamster ovary (CHO) cells transiently expressing the indicated EGFR mutants was labeled with biotin and EGFR immunoprecipitated (IP). After electrophoresis, proteins were transferred to a nitrocellulose filter and immunoblotted (IB) with streptavidin horseradish peroxidase (HRP). Whole-cell lysates were also resolved and IB with anti-EGFR antibodies (lower panel). (b) CHO cells were cotransfected with plasmids encoding a Stat3-luciferase reporter, green fluorescent protein (GFP) and the indicated EGFR mutant. Following serum starvation, cells were treated with (black columns) or without (grey columns) EGF for 8 h, before determination of the relative luminescence signal. The results are the meanss.d. of triplicates, normalized to the GFP signal. (c) Upper panels: forty-eight hours post transfection with a plasmid containing siRNA directed against EGFR (pSuper-EGFR), or a control vector (pSuper), HeLa monolayers were lysed and analysed with the indicated antibodies (left panel). The right panel presents immunoblotting analysis of EGFR expression in two HeLa stable clones transfected with a plasmid containing siRNA directed against EGFR. Lower panel: a stable clone (Clone 1) of HeLa cells transiently expressing siRNA-resistant L858R-EGFR or WT-EGFR, was incubated with EGF (5 ng/ml) at 37°C for the indicated time intervals. Cell-bound ligand was removed, and the level of surface receptors was determined by binding of a radiolabeled EGF at 4°C. The averages of triplicates and s.d. values (bars) are shown.

Full figure and legend (108K)

It has been previously reported that ligand-induced autophosphorylation of EGFR mutants decays relatively slowly (Lynch et al., 2004). Hence, we raised the possibility that EGF-induced downregulation of the mutants, namely their removal from the plasma membrane through an endocytic process, is impaired. To examine this model, we first stably knocked down the expression of the endogenous EGFR of HeLa cells, by transfection with either a control vector (pSuper) or a vector encoding an EGFR-specific siRNA. Immunoblotting analysis confirmed loss of EGFR expression in cells transfected with the pSUPER-EGFR plasmid (Figure 1c, upper left panel). Two stable clones were drug-selected, and immunoblotting of whole-cell extracts confirmed loss of expression in one clone (Clone 1; Figure 1c, upper right panel). Using clone 1 cells for adoptive expression of L858R-EGFR, 746-50-EGFR or WT-EGFR (all forms of EGFR were made resistant to the siRNA by introducing mutations at the respective target sites), enabled us to compare the rates of receptor downregulation under the same experimental conditions. The results presented in Figure 1c (lower panel) indicate that L858R-EGFR undergoes relatively slow endocytosis following treatment with EGF, in support of defective desensitization of lung cancer mutants of EGFR.

Ligand-induced downregulation of L858R/T790M-EGFR is defective in lung cancer cells

To confirm the defect in receptor downregulation and also address the biochemical mechanisms underlying enhanced signaling of L858R-EGFR, we used lung cancer cell lines naturally expressing EGFR. The cells we used were H358, which endogenously express WT-EGFR, and H1975 cells expressing a combination of WT and L858R-EGFR. According to several reports, the aberrant form of EGFR expressed in H1975 cells carries two mutations within the kinase domain (L858R/T790M); the T790M alteration prevents inhibition by Gefitinib (Kobayashi et al., 2005; Pao et al., 2005). When comparing the two lung cancer cell lines, we observed relatively high basal phosphorylation of the double mutant, as well as prolonged activation by EGF (Figure 2a). Consistent with these observations, L858R/T790M displayed enhanced activation of Akt and MAPK (Figure 2a).

Figure 2.

Ligand-induced downregulation of L858R/T790M-epidermal growth factor receptor (EGFR) is defective. (a) H358 (WT-EGFR) and H1975 (WT and L858R/T790M-EGFR) lung cancer cells were stimulated with EGF for the indicated time intervals and cell lysates analysed with the indicated antibodies. The experiment was repeated thrice. (b) H358 and H1975 NSCLC cells were incubated with EGF at 37°C for the indicated time intervals. Cell-bound ligand was removed, and the level of surface receptors was determined by binding of a radiolabeled EGF at 4°C. The average of triplicates and the respective s.d. (bars) are shown. H358 cells – dashed line, and H1975 cells – solid line. (c) H358 and H1975 cell monolayers were incubated at 37°C with a radiolabled EGF (10 ng/ml). At the indicated times, cell monolayers were acid – washed to remove surface-bound EGF. Radioactivity present in the acidic fraction was quantified in triplicates and the variation did not exceed 10% of the signal. The remaining cell-associated radioactivity was quantified similarly. The ratio obtained at each time point is presented.

Full figure and legend (98K)

Concentrating on ligand-induced downregulation of EGFR, we noted that ligand-activated WT-EGFR of H358 cells almost completely disappeared 15 min after stimulation with EGF, but EGFR of H1975 cells was detectable 2 h poststimulation (Figure 2a). This difference was confirmed by quantification of the immunoblots (data not shown). Hence, persistent autophosphorylation of L858R/T790M on several tyrosine residues, as well as prolonged activation of Akt and MAPK, might be attributed to a defect in ligand-induced degradation. Direct examination of receptor downregulation confirmed that L858R/T790M-EGFR is defective in ligand-induced endocytosis (Figure 2b), in similarity to the observations made in a reconstituted cell system (Figure 1c). Further, the rate of EGF internalization of a radioactive EGF into H1975 cells coexpressing WT-EGFR and L858R/T790M, was slower compared to H358 cells expressing WT-EGFR alone (Figure 2c). In contrast, internalization of a fluorescent derivative of transferrin displayed similar rates in H1975 and H358 cells (data not shown), suggesting intactness of the endocytic machinery of H1975 cells. The differences in receptor downregulation rates were highly reproducible in lung cancer cells, as well as in transfected cells (Figure 1c and data not shown), leading us to conclude that the ability of L858R/T790M-EGFR to generate enhanced and prolonged intracellular signals is attributable to a major defect in receptor desensitization.

An internal deletion mutant of EGFR evades ligand-induced downregulation

We utilized the H1650 lung cancer cell line that expresses 746-50-EGFR to determine whether additional non-small cell lung cancer (NSCLC) mutants, as revealed with L858R/T790M-EGFR, utilize defective receptor downregulation to prolong their signaling. Similar to the L858R/T790M mutant, 746-50-EGFR not only enhances, but also prolongs intracellular signals such as phosphorylation of Erk/MAPK and Akt (Figure 3a). Persistent activation of downstream effectors is likely due to a reduction in both the rate of EGFR internalization (Figure 3b), and the rate of ligand-induced receptor degradation (Figure 3a). Because the rate of receptor endocytosis depends on the extent of saturation by EGF (Sigismund et al., 2005), we tested the rate of EGF internalization at low and high ligand concentrations and observed a consistent defect in the case of 746-50-EGFR (Figure 3c). Because ubiquitinylation by an E3 ubiquitin ligase, c-Cbl, is an essential step preceding ligand-induced degradation of EGFR (reviewed in Dikic and Giordano, 2003; Marmor and Yarden, 2004), we compared the patterns of EGF-induced modification of 746-50-EGFR and WT-EGFR (Figure 3d). This analysis revealed relatively weak ligand-induced ubiquitinylation and degradation of 746-50-EGFR (note limited band up-smearing indicative of inefficient ubiquitinylation). A similar defect in ligand-induced ubiquitinylation was observed with the partly overlapping deletion mutant, 747-53S-EGFR, expressed in an ectopic cellular system (data not shown). In conclusion, evasion from desensitization is a shared mechanism exploited by several NSCLC mutants of EGFR.

Figure 3.

A deletion mutant of epidermal growth factor receptor (EGFR) evades EGF-induced downregulation. (a) The H358 (WT-EGFR) and the H1650 cell line (746-50-EGFR) were stimulated with EGF for the indicated time intervals. Whole-cell lysates were analysed with the indicated antibodies. (b) EGFR downregulation was analysed, in triplicates, with H358 and H1650 cell monolayers as described in (b) of Figure 2. S.d. are shown (bars). (c) H358 (WT-EGFR) and H1650 (746-50-EGFR) cell monolayers were incubated at 37°C with a radio-labled EGF (2 or 50 ng/ml). At the indicated time intervals, the medium was removed and cell monolayers were acid – washed to remove surface-bound EGF. Radioactivity present in the acidic fraction ('Surface') was quantified in triplicates. The remaining cell-associated radioactivity ('Internalized') was similarly quantified. The ratio obtained at each time point is presented. (d) Monolayers of H358 and H1650 cell lines were stimulated with EGF for the indicated time intervals and cell lysates were analysed with the indicated antibodies. The difference in receptor ubiquitinylation was observed in three other experiments.

Full figure and legend (108K)

L858R-EGFR displays abnormal ligand-induced ubiquitinylation and coupling to c-Cbl

Comparative analysis of ligand-induced receptor ubiquitinylation revealed a similar defect in L858R/T790M-EGFR modification in H1975 cells (Figure 4a). The defective ubiquitinylation of L858R/T790M-EGFR was despite similar levels of c-Cbl and could be further distinguished by the lack of high molecular weight smearing when analysed with an anti-phosphotyrosine antibody (Figure 4a; lowermost panel). It is important noting that H1975 cells coexpress WT and mutant EGFR molecules, which partly masks the true characteristics of the mutant receptors. In contrast, ectopic expression in CHO cells enables direct analysis of mutant forms. Indeed, transfection of single mutants (L858R and T790M), the respective double mutant, or 746-50, into CHO and into HEK-293T cells confirmed the difference in ubiquitinylation (data not shown).

Figure 4.

L858R-epidermal growth factor receptor (EGFR) displays abnormal ligand-induced ubiquitinylation and coupling to c-Cbl. (a) The H358 (WT-EGFR) and the H1975 cell lines (L858R/T790M-EGFR) were treated with EGF for the indicated time intervals. Cell lysates and EGFR immunoprecipitates were analysed with anti-ubiquitin (Ub) and other antibodies. (b) Coimmunoprecipitation of EGFR with c-Cbl was analysed in H358 and in H1975 cells expressing the indicated forms of EGFR. Cells were stimulated with EGF and the presence of c-Cbl in EGFR immunoprecipitates was analysed. Tyrosine-phosphorylated Cbl proteins (arrow) were detected with an antibody specific to phosphorylated Cbl (pCbl; at tyrosine 731). (c) HEK-293T cells were transfected with vectors encoding for the indicated forms of EGFR, along with a c-Cbl plasmid. Following 48 h, cell monolayers were starved and thereafter stimulated with EGF (20 ng/ml) for 8 min. EGFR was IP and after electrophoresis, immunoprecipitates and whole-cell lysates were IB with the indicated antibodies. (d) Chinese hamster ovary (CHO) cells were transiently transfected with vectors encoding for the indicated forms of EGFR, along with a c-Cbl plasmid. Following 48 h, cell monolayers were incubated with EGF for the indicated time intervals. c-Cbl was IP and after electrophoresis, immunoprecipitates and whole-cell lysates were IB with the indicated antibodies. (e) HEK-293T cells were transfected with plasmids encoding for the indicated forms of EGFR. Forty-eight hours post transfection, WT- and L858R-EGFR were IP and subjected to an in vitro ubiquitinylation assay with a radiolabeled ubiquitin and with or without GST-c-Cbl. Receptor immunoprecipitates were resolved by electrophoresis and proteins transferred to nitrocellulose filters, which were first autoradiographed (upper panels) and then IB (lower panels).

Full figure and legend (143K)

In order for c-Cbl to ubiquitinylate EGFR, it must form a physical complex with and undergo phosphorylation by EGFR (Levkowitz et al., 1999). Although the L858R/T790M-EGFR mutant is expressed at higher levels, the interaction between this form of EGFR and c-Cbl is impaired as revealed by testing EGF-induced coprecipitation of c-Cbl with either WT-EGFR or L858R/T790M-EGFR (Figure 4b). Unlike EGF-induced physical association of WT-EGFR with c-Cbl, association of the L858R/T790M mutant with c-Cbl was only weakly affected upon stimulation with EGF. Lack of c-Cbl-EGFR complex formation was confirmed in HEK-293T cells transfected with L858R-EGFR and stimulated with EGF (Figure 4c). In line with this finding, analysis of the status of phosphorylation of c-Cbl, by using either antibodies specific to phosphorylated c-Cbl (pCbl; Figure 4c), or antibodies to phosphotyrosine (pTyr; Figure 4d), revealed relatively weak modification upon stimulation of the mutant receptor in both NSCLC cells and in transfected CHO cells, respectively. To assess whether L858R/T790M-EGFR is inherently refractory to ubiquitinylation, we employed an in vitro assay. This assay used a radiolabeled ubiquitin and a recombinant c-Cbl protein, along with reticulocyte lysate. The reaction was performed with EGFR molecules isolated from either transfected cells (Figure 4e), or from lung cancer cells (data not shown). When removed from the context of living cells, L858R-EGFR and L858R/T790M-EGFR underwent an apparently normal, c-Cbl-dependent ubiquitinylation (Figure 4e and data not shown). Conceivably, the altered structure of the mutant kinase domain does not abrogate ubiquitinylation. Instead, we explore below the possibility that cellular factors extrinsic to EGFR and c-Cbl help sequester the mutant receptor from ubiquitinylation and downregulation.

Enhanced interaction of L858R/T790M-EGFR with HER2

The most direct mechanism to abrogate c-Cbl-mediated ubiquitinylation of L858R/T790M would be differential phosphorylation at tyrosine 1045 of EGFR, the only direct docking site for c-Cbl (Levkowitz et al., 1999). However, tyrosine 1045 of both L858R/T790M-EGFR and 746-50-EGFR underwent robust phosphorylation (Figures 2a, 3a and 5a). An alternative mechanism involves heterodimerization with HER2, an internalization-defective member of the HER/ErbB family (Baulida et al., 1996), whose interaction with c-Cbl is impaired, probably because HER2 cannot trans-phosphorylate tyrosine 1045 of EGFR (Levkowitz et al., 1996; Graus Porta et al., 1997; Muthuswamy et al., 1999; Worthylake et al., 1999). Consistent with this scenario, we observed high basal phosphorylation of HER2 in both H1975 and H1650 cells relative to H358 cells, as well as prolonged ligand-induced tyrosine phosphorylation of HER2 (Figures 3a and 5a).

Figure 5.

Enhanced functional and physical interactions of L858R/T790M-epidermal growth factor receptor (EGFR) with HER2. (a) The H358 (WT-EGFR) and H1975 (L858R/T790M-EGFR) cell lines were treated with EGF for the indicated time intervals. Whole-cell lysates were analysed with the indicated antibodies. (b) H358 and H1975 cell monolayers were incubated with or without EGF at 4°C for 60 min. Cells were lysed in the presence of a chemical cross-linking reagent (BS³). Thereafter, cell lysates were cleared and analysed with the indicated antibodies. D: dimers; M: monomers. (c) Triplicate monolayers of H358 and H1975 cells were incubated with a radiolabeled EGF (2 ng/ml) for 2 h at 4°C. Cell monolayers were washed and fresh binding buffer was replaced. At the indicated times, the medium was collected and radioactivity present was quantified. The remaining cell-associated radioactivity was similarly quantified and the ratio obtained at each time point is presented. The experiment was repeated thrice and the variation within triplicates did not exceed 10%. (d) H358 (WT-EGFR) and H1975 (WT and L858R/T790M-EGFR) cell monolayers were incubated with sequential dilutions of a radiolabeled EGF for 2 h at 4°C. Duplicate monolayers were incubated with the same dilutions except in the presence of 100-fold-unlabeled EGF. After incubation, cell monolayers were washed and the remaining cell-associated radioactivity was quantified. Specific binding of EGF was calculated and presented as Scatchard plots. The K_d values calculated as 1.250.24 nM ((L858R/T790M-EGFR) and 2.50.9 nM (WT-EGFR).

Full figure and legend (135K)

To test the prediction that L858R/T790M-EGFR interacts with HER2 before stimulation with EGF, we applied a covalent crosslinking reagent capable of stabilizing EGFR–HER2 complexes. Lung cancer cells expressing WT-EGFR were either stimulated with EGF or left untreated, and the crosslinking reagent added to whole-cell extracts, before immunoprecipitation of HER2. Blotting HER2 immunoprecipitates with anti-EGFR antibodies detected a covalently linked heterodimeric form of WT-EGFR only after stimulation with EGF (Figure 5b). In contrast and in line with our prediction, significant EGF-independent heterodimerization of L858R/T790M-EGFR was detectable when analysing HER2 immunoprecipitates prepared from H1975 cells (compare the dimer bands of untreated cells in the uppermost panel of Figure 5b).

Heterodimerization with HER2 decelerates ligand dissociation rates, thereby increasing binding affinity (Sliwkowski et al., 1994; Karunagaran et al., 1996). Hence, as an independent test for the enhanced presence of HER2-L858R/T790M heterodimers, we examined the prediction that L858R/T790M-expressing cells bind EGF with higher affinity and release the ligand more slowly than WT-EGFR-expressing cells. Lung cancer cells were loaded at 4°C with a radiolabeled EGF and the rates of release of radioactivity were monitored. The results of this assay showed that L858R/T790M-expressing cells are characterized by a slower ligand dissociation rate relative to the rapid release from WT-EGFR expressing cells (Figure 5c). In addition, L858R/T790M-expressing cells displayed higher EGF binding affinity than H358 cells (K_d=1.25 vs 2.5 nM; Figure 5d). Taken together, these observations are consistent with a significant propensity of the L858R/T790M-EGFR to recruit HER2 into heterodimers.

Enhanced interaction with HER2 suggests a mechanism for defective downregulation of L858R-EGFR

To further examine the inferred propensity of EGFR mutants to recruit HER2, we reconstituted the interaction between L858R-EGFR and HER2 in CHO cells. As expected, when coexpressed with WT-EGFR, HER2 underwent no tyrosine phosphorylation, unless the cells were prestimulated with EGF (Figure 6a; panel labeled pHER2). In contrast, when coexpressed with the mutant form of EGFR, HER2 displayed high basal phosphorylation similar to the extent of phosphorylation observed in EGF-stimulated cells coexpressing WT-EGFR. These observations are consistent with stronger interactions between HER2 and the L858R mutant, relative to the interaction of HER2 with WT-EGFR. Indeed, an independent assay of downstream signaling to Stat3 demonstrated that relative to WT-EGFR, coexpression of L858R and HER2 significantly elevated the basal STAT3 activity, almost to the level achieved upon stimulation with EGF (Figure 6b).

Figure 6.

Enhanced interactions with HER2 may explain the defective downregulation of L858R-epidermal growth factor receptor (EGFR). (a) Chinese hamster ovary (CHO) cells were cotransfected with vectors encoding for either WT-EGFR or L858R-EGFR, with or without an HER2 expression plasmid. Forty-eight hours post transfection, cell monolayers were treated with EGF for 15 min. Cell lysates were analysed with the indicated antibodies. (b) CHO cells cotransfected with the indicated vectors (EGFR and HER2), along with plasmids encoding for a Stat3-luciferase reporter gene and GFP, were treated with (black columns) or without (grey columns) EGF and the relative luminescence signal determined and normalized as described in (b) of Figure 1. S.d. within triplicates are presented (bars). (c) H358 (WT-EGFR) and H1975 (L858R/T790M-EGFR) cells were treated with a mixture of anti-HER2 monoclonal antibodies (Herceptin and L26; 10 g/ml each). Twenty hours after antibody treatment, cell monolayers were treated with EGF for the indicated time intervals and lysates electrophoresed and IB with the indicated antibodies. (d) CHO cells were cotransfected with vectors encoding for WT-EGFR or L858R-EGFR, Flag-Ub, c-Cbl and an increasing dose of a HER2-encoding plasmid. Cells monolayers were stimulated for 8 min with EGF before immunoblotting analyses. Receptor ubiquitinylation signals, obtained from the major ubiquitinylated species, were quantified and presented as a function of HER2 expression. AU, arbitrary units.

Full figure and legend (130K)

To establish the involvement of HER2 in the resistance of L858R to ligand-induced degradation, we attempted downregulation of HER2 using a combination of two monoclonal antibodies to HER2, which is known to effectively target the receptor for degradation in lysosomes (Friedman et al., 2005). The results, we obtained, (Figure 6c) indicate that antibody-induced downregulation of HER2 transforms the relatively ligand-refractory mutant receptor (compare the decline from lanes 1 to 4) into a ligand-sensitive state, which displays significant downregulation (compare the decline from lanes 5 to 8). This conclusion relates not only to EGFR's protein level, but also to the relative decrease in receptor autophosphorylation (lower panel in Figure 6c). These observations are in line with the notion that HER2 protects WT-EGFR from EGF-induced desensitization (Muthuswamy et al., 1999), and our contention that mutant receptors are better coupled to HER2. To firmly test this model, we gradually overexpressed HER2 in EGFR-expressing CHO cells and stimulated them with EGF. Along with stabilization of ligand-activated WT-EGFR and L858R-EGFR, HER2 overexpression remarkably reduced ubiquitinylation of L858R-EGFR, but only moderately affected ubiquitinylation WT-EGFR (Figure 6d). In conclusion, the ability of HER2 to regulate ubiquitinylation (Figure 6d) and degradation of L858R-EGFR (Figure 6c) is consistent with the observed physical pre-association (Figure 5b) and trans-phosphorylation of HER2 in lung cancer cells (Figure 5b), which explain how aberrant receptors evade physiological desensitization.

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Discussion

The major process of homeostatic regulation of EGFR and other receptor tyrosine kinases involves clustering of ligand-activated receptors in clathrin-coated areas of the plasma membrane, ubiquitinylation and sorting for degradation in lysosomes (reviewed in Wiley and Burke, 2001; Marmor and Yarden, 2004). Several growth factor receptors escape this inactivation pathway by means of overexpression, which saturates the clathrin-mediated route of endocytosis. The overexpression mechanism may be relevant to head and neck and other types of cancer, which overexpress EGFR. However, although a few mutant forms of EGFR are moderately overexpressed in NSCLC (Tracy et al., 2004; Amann et al., 2005), additional modes of escape are needed to maintain the active state of EGFR mutants at the plasma membrane, the site from which EGFR generates mitogenic (Waterman et al., 2002) and oncogenic signals (Wells et al., 1990). By concentrating on a frequently observed mutant, L858R, we raise the possibility that this mutant receptor evades homeostatic regulation by collaborating with HER2.

Unlike the transient EGF-induced signals that characterize WT-EGFR, the Akt and to some extent also the Erk pathway, are persistently activated in NSCLC cells expressing mutant forms of EGFR (Sordella et al., 2004; Amann et al., 2005). In contrast with WT-EGFR, which undergoes rapid clearance from the plasma membrane followed by lysosomal degradation, the mutants we studied (primarily L858R, 746-50 and L858R/T790M) undergo relatively slow endocytosis and they internalize bound EGF molecules significantly slower than WT-EGFR (Figures 2 and 3). As a result, EGFR mutants resist ligand-induced degradation, such that their phosphorylated forms are detectable for several hours after stimulation with EGF (Figures 2a and 3a). Conceivably, the relatively slow clearance of mutant EGFR molecules enables persistent signaling and leads to stronger mitogenic and antiapoptotic signals.

Why is the EGF-induced downregulation of mutant forms of EGFR defective? Ligand-induced receptor autophosphorylation facilitates Cbl-mediated receptor ubiquitinylation. This generates multiple docking sites for endocytotic adaptor proteins possessing ubiquitin-binding domains (Polo et al., 2002). Our studies revealed a major failure in the initial steps of receptor ubiquitinylation and endocytosis. The most prominent aspect is a relatively weak ligand-induced ubiquitinylation of L858R, L858R/T790M and 746-50, along with an inability of L858R to physically recruit and phosphorylate c-Cbl upon stimulation with EGF (Figure 4). The mechanism underlying this defect is incompletely understood, but our data suggest involvement of a third component, namely HER2. Heterodimers comprising EGFR and HER2 are endowed with relatively high transforming activity (Kokai et al., 1989). The ability of HER2 to enhance EGFR signaling has been attributed to several unique aspects of the heterodimers, which allow them to signal persistently. These include a slow rate of EGF dissociation (Karunagaran et al., 1996) and a relatively slow rate of EGF-induced receptor degradation (Worthylake et al., 1999). Presumably, the endocytosis defect of HER2 is due to a reduced ability to recruit c-Cbl (Levkowitz et al., 1996), and a defect in the ability of EGFR to interact with c-Cbl when present in HER2-containing heterodimers (Muthuswamy et al., 1999). According to an alternative model, HER2 inhibits downregulation of EGFR in a mechanism that entails serine phosphorylation at residue 1113, which flanks a c-Cbl-docking site at tyrosine 1112 (Ouyang et al., 2001).

For several reasons, we propose that a propensity to engage into heterodimers with HER2 underlies the ability of mutant EGFRs like L858R to escape ubiquitinylation by c-Cbl. First, a mutant form of EGFR displays ligand-independent heterodimerization with HER2, unlike the WT receptor (Figure 5b). Second, HER2 is constitutively hyperphosphorylated in mutant-expressing lung cancer cells and CHO cells (Figures 3a, 5a, and 6a). Third, EGF binds more avidly to mutant-expressing cells, and its rate of dissociation is retarded (Figure 5), consistent with abundance of EGFR-HER2 heterodimers. In addition, forced overexpression of HER2 enhances the basal transcriptional signaling of L858R (Figure 6b) and reduces ubiquitinylation of the mutant receptor (Figure 6d). On the other hand, reducing HER2 expression using a combination of monoclonal antibodies enhanced ligand-mediated receptor desensitization (Figure 6c). These observations imply that mutants like L858R evolve a propensity to heterodimerize with HER2 even in the absence of a stimulating ligand. Within the heterodimer, EGFR trans-phosphorylates HER2 and undergoes enhanced phosphorylation. This leads to recruitment of several signaling molecules, but c-Cbl is excluded from the complex (Levkowitz et al., 1996; Graus Porta et al., 1997; Muthuswamy et al., 1999; Worthylake et al., 1999), probably because HER2 cannot trans-phosphorylate tyrosine 1113 of EGFR (Muthuswamy et al., 1999), and therefore ubiquitinylation and downregulation of mutant forms of EGFR are defective. According to a recently proposed alternative model, heat shock protein 90 uncouples mutant forms of EGFR from c-Cbl (Yang et al., 2006). Also relevant to our model is the ability of EGFR mutants to recruit another family member, namely ErbB-3 (Engelman et al., 2005), a kinase-defective receptor whose downregulation is defective (Waterman et al., 1999).

In summary, our studies identified a defect in ligand-induced ubiquitinylation and degradation of mutant forms of EGFR. In addition, based on several indirect lines of evidence, we propose that a partnership with HER2 underlies the ability of mutant receptors to evade desensitization and prolong signaling. If this model is confirmed by additional studies, it will be interesting to examine the prediction that intercepting HER2 in lung cancer will reduce oncogenicity of mutated forms of EGFR.

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Materials and methods

Reagents and antibodies

Unless indicated, materials were purchased from Sigma (St Louis, MO, USA). Na¹²⁵I and chemiluminescence kit were from Amersham Pharmacia Biotech (Buckinghamshire, UK) and IODOGEN from Pierce (Rockford, IL, USA). Lipofectamine and oligofectamine were supplied by Invitrogen (Carlsbad, CA, USA). Monoclonal antibodies to EGFR and HER2 were from Alexis Biotechnology (Lausen, Switzerland) or generated in our laboratory. Antibodies to p845-, p1045-, p1068-, p1173-EGFR, p1221-HER2, p731-c-Cbl and phospho-Akt were obtained from Cell Signaling (Beverly, MA, USA). Antibodies to ubiquitin were obtained from Babco (Berkley, CA, USA). NSCLC cell lines were purchased from the American Type Tissue Culture collection (Manassas, VA, USA).

Buffers

The following buffers were used: Binding buffer: Dulbecco's modified Eagle's medium supplemented with 0.5% bovine serum albumin and 20 mM 4-(2-hydroxyethyl)-1-piperazineethanesulfonic acid (HEPES) (pH 7.5). Lysis buffer: 0.1 N NaOH and 0.1% sodium dodecyl sulfate. HNTG: 20 mM HEPES (pH 7.5), 150 mM NaCl, 0.1% Triton X-100 and 10% glycerol. Tris-buffered saline Tween-20 (TBST): 20 mM Tris–HCL (pH 7.5), 0.15 M NaCl and 0.05% Tween-20. Solubilization buffer: 50 mM HEPES (pH 7.5), 150 mM NaCl, 10% glycerol, 1% Triton X-100, 1 mM ethylenediaminetetraacetic acid, 1 mM ethylene glycol bis(-aminoethylether)-N,N,N',N', -tetraacetic acid, 0.2 mM Na₃VO₄ and a protease inhibitor cocktail.

Construction and transfection of expression vectors

EGFR mutants were constructed by site-directed mutagenesis using the QuikChange mutagenesis kit (Stratagene, La-Jolla, CA, USA). All other vectors have been described (Levkowitz et al., 1999). For transfection, cells were grown to 30–50% confluence and transfection was preformed using Oligofectamine (NSCLC cells) or Lipofectamine (CHO cells). The total amount of DNA in each transfection was normalized with the pcDNA3 plasmid.

Immunoprecipitation and immunoblotting analyses

In experiments, where EGF was introduced, the cells were starved overnight in serum-free medium, and incubated for the indicated times at 37°C with EGF (20 ng/ml). For immunoprecipitation, lysates were incubated for 1–2 h at 4°C with antibodies precoupled to anti-mouse immunoglobulin G-agarose beads. The immunoprecipitates were washed thrice with HNTG solution, resolved by gel electrophoresis and electrophoretically transferred to a nitrocellulose membrane. Membranes were blocked in TBST buffer containing 10% low-fat milk, blotted with a primary antibody for 1 h, washed with TBST and incubated for 30 min with a secondary antibody linked to horseradish peroxidase (HRP). Immunoreactive bands were detected using chemiluminescence.

Ligand binding and dissociation studies

Monolayers of cells were incubated with different concentrations of ¹²⁵I-EGF for 2 h at 4°C. Simultaneously, identical cell monolayers were coincubated with different concentrations of ¹²⁵I-EGF and excess (100-fold) unlabeled ligand. The cells were washed three times with ice-cold binding buffer. Labeled cells were lysed in lysis buffer and their radioactivity was determined. For ligand dissociation analysis, cells were first incubated with ¹²⁵I-EGF (2 ng/ml) for 2 h at 4°C and then washed three times. Ligand dissociation was monitored by incubating the cells in binding buffer for various periods of time at 4°C, and the amounts of released and cell-associated radioactive ligand were determined.

Stat3 transcription assay

Cells were transfected with plasmids encoding green fluorescent protein (GFP), WT-EGFR, EGFR mutants or HER2, along with a Stat3-luciferase plasmid containing a Stat3 response element fused to a luciferase reporter gene. Twenty-four hours later, the cells were split into 24-well plates, and following 12 more hours, the cells were serum starved for 12 h and then treated with EGF (20 ng/ml) for 8 h or left untreated. The luciferase reporter assay was performed using a kit (Promega; Madison, WI, USA). Light intensity was normalized to GFP expression levels.

Cell surface biotinylation

For biotinylation, cells were washed with ice-cold saline and then incubated for 60 min at 4°C with N-hydroxysuccinimide-biotin (biotin-X-NHS, 0.5 mg/ml; Calbiochem, San Diego, CA, USA) dissolved in borate buffer (10 mM boric acid, 150 mM NaCl; pH 8.0). Coupling of biotin was blocked by cell rinsing with a solution of 15 mM glycine in saline.

Ligand internalization assay

EGF was labeled with ¹²⁵I and IODOGEN as recommended by the manufacturer. Ligand-induced internalization was measured as follows. Cells were incubated with ¹²⁵I-EGF (10 ng/ml) at 37°C for 2–10 min. At the indicated times, the monolayers were rapidly washed and surface-bound ¹²⁵I-EGF was removed using acetic acid wash (surface-bound ligand). The cells were then solubilized (internalized ligand). Non-specific binding, measured in the presence of molar excess (200-fold) of unlabeled ligand, represented less than 10% of the total cell-associated radioactivity.

Receptor downregulation assay

Cells grown in 24-well plates were serum-starved for at least 12 h. Thereafter, cell monolayers were incubated at 37°C for the indicated time intervals with EGF (20 ng/ml) in binding buffer and then rinsed. Surface-bound EGF was removed by using acid wash followed by neutralization with cold binding buffer. The number of surface-exposed ligand binding sites was determined by incubating cells for 90 min at 4°C with a radiolabeled EGF. Nonspecific binding was measured in the presence of excess of unlabeled ligand.

Covalent crosslinking assay

Cell monolayers were incubated with EGF on ice for 1 h. Thereafter, cells were washed twice and scraped in cold saline. Then, cells were lysed in the presence of BS³ (2 mM). Following incubation for 20 min on ice, the reaction was quenched with glycine (50 mM), aggregates and nuclei precipitated (20 min at 14 000 r.p.m.) and covalent complexes analysed using immunoprecipitation and gel electrophoresis.

In vitro ubiquitinylation assay

Ubiquitin (10 g) was incubated with Na¹²⁵I (1mCurie) and the IODOGEN reagent (Pierce, Rockford, IL, USA). Following incubation at 22°C (5 min), free iodine was separated from ubiquitin using D-Salt Excellulose Desalting Column (Pierce). The reaction mixture contained rabbit reticulocyte lysate supplemented with 40 mM Tris, pH 7.5, 5 mM MgCl₂, 2 mM dithiothreitol, 2 mM ATP--S and ¹²⁵I-labeled ubiquitin. Bacterially purified recombinant GST-Cbl (50 g) was added as indicated. EGFR was immunopurified from lung cancer cells and receptor-bound beads were incubated with the reaction mixture for 1 h at 30°C. Thereafter, the beads were washed extensively and analysed by electrophoresis and autoradiography.

Statistical analyses

All analyses presented were repeated at least thrice, and all quantitative analyses were performed in triplicates. S.d. were calculated and shown (as bars), but since variation within triplicates rarely exceeded 10% of the signal, the bars do not show in all figures.

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Acknowledgements

We thank Drs Wallace Langdon and Dirk Bohmann for plasmids. Our laboratory is supported by research grants from the National Cancer Institute (grant CA72981, to YY), the Israel Cancer Research Fund and the German-Israel Foundation. YY is the incumbent of the Harold and Zelda Goldenberg Professorial Chair.

Source from : http://www.nature.com/onc/journal/v26/n49/full/1210503a.html

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Crystallizing the Early Cosmos

2007-10-26T18:20:00.000+07:00

Blowing hot and cold.
Zones of temperature variations (hot in red and cold in blue) in a computer simulation of the cosmic background radiation signify a texture in the early universe.

Credit: V. Travieso and N. Turok

By Phil Berardelli

ScienceNOW Daily News
25 October 2007

A new analysis of the afterglow of the big bang supports a novel theory of how the universe took shape, theoretical physicists say. The existence of a curious cold spot in the sky suggests that the cosmos quickly sported flaws that resulted in the formation of the first stars and galaxies.

Studies of the big bang afterglow, also known as the cosmic microwave background (CMB), have already revealed plenty about how the universe came to be. The continuing expansion of the universe has stretched the light blasting out of the big bang into microwaves and cooled it to just 2.7° above absolute zero. In 2003, researchers working with NASA's orbiting Wilkinson Microwave Anisotropy Probe (WMAP) mapped fluctuations in the temperature of the CMB, which varies by only a few parts in 100,000 across the sky. Comparing the data with theoretical models confirmed that the universe sprang into existence precisely 13.7 billion years ago (ScienceNOW, 11 February 2003). The variations in the CMB's temperature also trace out slight fluctuations in the density of the nascent universe, which eventually seeded the galaxies.

The WMAP data generally support theorists' understanding of the origins of the universe, but they also show some quirks that could point to new and more exotic physics. For example, researchers have known that the CMB sports a large cold spot. Now a team says the cold spot is too large to be explained by standard models and is evidence that, like a giant patchwork quilt, the universe might have something like texture. "This is surprising," says physicist and lead author Marcos Cruz of the Instituto de Física de Cantabria in Spain.

The cold spot may be evidence that the early universe underwent a change somewhat akin to the formation of ice from water, Cruz's team argues online today in Science. Ice contains structural defects wherever water molecules do not align perfectly within the crystal. When the four forces--gravity, electromagnetism, the weak nuclear force, and the strong nuclear force--split off from an ur-force not long after the big bang, the universe might have been threaded with defects that gave it a texture. And the CMB may reflect that texture with its temperature variations, including the cold spot, the researchers argue.

Here's how it might have happened: The separation of the forces involves a process called symmetry breaking, which is a bit like arbitrarily choosing a direction on a compass to call north. If different directions are chosen in different regions of space, then defects would arise between them. Containing energy, these defects would then exert a gravitational pull that would mottle the CMB and accumulate matter that would eventually become stars and galaxies. A statistical analysis of the CMB shows that the cold spot is consistent with this scenario, the researchers say.

Others are skeptical. "Further tests and stronger evidence are needed," says physicist Robert Caldwell of Dartmouth College. He agrees that if confirmed, the conclusions would give detailed clues to how nature's forces separated after the big bang. Still, he says, they're not entirely compatible with other observations. There's also a chance, the authors concede, that the cold spot might be just a fluke--"an unusually large and rare fluctuation in the density of matter in that region of the sky."

Source from : http://www.sciencemag.org/

Journal of Human Hypertension (2007) 21, 861–867; doi:10.1038/sj.jhh.1002244; published online 21 June 2007

2007-10-24T14:28:00.000+07:00

Journal of Human Hypertension (2007) 21, 861–867; doi:10.1038/sj.jhh.1002244; published online 21 June 2007
Matrix metalloproteinase-9 polymorphism contributes to blood pressure and arterial stiffness in essential hypertension

S Zhou1, J Feely1,2, J P Spiers1 and A Mahmud1,2
1Department of Pharmacology and Therapeutics, Trinity College Dublin, Dublin, Ireland
2Hypertension Clinic, St James's Hospital, Dublin, Ireland

Correspondence: Dr A Mahmud, Department of Pharmacology and Therapeutics, Trinity Centre for Health Sciences, St James's Hospital, Dublin 8, Ireland. E-mail: mahmuda@tcd.ie

Received 19 January 2007; Revised 29 April 2007; Accepted 5 May 2007; Published online 21 June 2007.

Abstract

Arterial stiffness is an independent predictor of cardiovascular events in a hypertensive population. Serum levels of matrix metalloproteinase (MMP)-9 are associated with arterial stiffness and predict cardiovascular risk. We investigated the role of MMP-9 polymorphism -1562C>T on blood pressure (BP) and arterial stiffness in a newly diagnosed hypertensive population. Untreated hypertensive patients (n=215, mean age 4613 years) were studied. Supine BP, carotid-femoral pulse wave velocity (PWV) and augmentation index were assessed. Serum biochemistry and plasma MMP-9 concentrations were measured and genotyping performed following extraction of genomic DNA. BP, aortic PWV and serum MMP-9 levels were significantly higher in T-allele carriers of the -1562C>T polymorphism with a significant gene–dose effect (P<0.0001).>T polymorphism emerged as an independent predictor of systolic BP (R2=0.25, P<0.0001), diastolic BP (R2=0.16, P<0.0001) and PWV (R2=0.47,P<0.0001). This is the first study to show the effect of MMP-9 polymorphism on BP and aortic stiffness in a hypertensive population. These results suggest that hypertensive patients carrying the T allele may be at increased risk of cardiovascular events.

Keywords: MMP-9 gene polymorphism, arterial stiffness, aortic pulse wave velocity, augmentation index, MMP-9 levels

Source : Journal of Human Hypertension
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Endothelial cells of human colorectal cancer and healthy colon reveal phenotypic differences in culture

2007-10-20T12:35:00.000+07:00

Laboratory Investigation (2007) 87, 1159–1170; doi:10.1038/labinvest.3700671; published online 17 September 2007

Endothelial cells of human colorectal cancer and healthy colon reveal phenotypic differences in culture

Vera Simone Schellerer^1,2, Roland Siegfried Croner¹, Kristina Weinländer², Werner Hohenberger¹, Michael Stürzl² and Elisabeth Naschberger²

¹Department of Surgery, Friedrich-Alexander University, Erlangen, Germany
²Division of Molecular and Experimental Surgery, Department of Surgery, Friedrich-Alexander University, Erlangen, Germany

Correspondence: Professor M Stürzl, PhD, Division of Molecular and Experimental Surgery, Department of Surgery, Friedrich-Alexander University of Erlangen-Nuremberg, Schwabachanlage 10, Erlangen 91054, Germany. E-mail: michael.stuerzl@chir.imed.uni-erlangen.de

Received 14 March 2007; Revised 3 August 2007; Accepted 3 August 2007; Published online 17 September 2007.

Abstract

Antiangiogenic drugs have been used successfully for the treatment of colorectal cancer (CRC). Viable tumor endothelial cells (TEC) and normal endothelial cells (NEC) of uninvolved colon tissue of the same patient have not been available to optimize treatment strategies in vitro. Therefore, our target was to establish a protocol for the isolation of TEC and NEC. These cells were isolated with very high purity via magnetic cell sorting of tissue samples obtained from CRC and healthy colon of eight patients. TEC and NEC expressed CD31, CD105, VE-cadherin, VCAM-1, ICAM-1 and E-selectin, formed capillaries in basal membrane extract and were able to take up acetylated low-density lipoprotein. They were negative for podoplanin, CD45, CD68 and cytokeratin-20 indicating blood vessel endothelial lineage. Intense staining of von Willebrand factor (vWF) was observed in five of eight NEC cultures, whereas vWF was absent or only slightly expressed in all TEC cultures in vitro. Low intracellular concentration of vWF was also detected in TEC and NEC at the tissue level. This demonstrated that differences exhibited by TEC and NEC in vivo are stably perpetuated in culture. The isolated cultures may provide a useful in vitro model to elucidate epigenetic effects on angiogenesis in cancer and to optimize antiangiogenic therapy.

Keywords:

angiogenesis, colorectal cancer, endothelial cells, von Willebrand factor

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Source : http://www.nature.com/labinvest/journal/v87/n11/abs/3700671a.html

ROCK-II mediates colon cancer invasion via regulation of MMP-2 and MMP-13 at the site of invadopodia as revealed by multiphoton imaging

2007-10-20T12:32:00.000+07:00

Laboratory Investigation (2007) 87, 1149–1158; doi:10.1038/labinvest.3700674; published online 17 September 2007

ROCK-II mediates colon cancer invasion via regulation of MMP-2 and MMP-13 at the site of invadopodia as revealed by multiphoton imaging

Ramana Vishnubhotla^1,*, Shan Sun^1,*, Jameela Huq¹, Marinka Bulic², Anil Ramesh², Grace Guzman³, Michael Cho¹ and Sarah C Glover^1,2,4

¹Department of Bioengineering, University of Illinois at Chicago, Chicago, IL, USA
²Department of Medicine, University of Illinois at Chicago, Chicago, IL, USA
³Department of Pathology, University of Illinois at Chicago, Chicago, IL, USA
⁴Department of Medicine, Jesse Brown VA Medical Center, Chicago, IL, USA

Correspondence: Dr SC Glover, DO, Department of Medicine, University of Illinois at Chicago, 840 South Wood Street, MC 716, Chicago, IL 60612, USA. E-mail: sarahg@uic.edu

^*These authors contributed equally to this work.

Received 1 February 2007; Revised 8 August 2007; Accepted 10 August 2007; Published online 17 September 2007.

Abstract

The ROCK-II isoform of Rho's downstream effector, Rho kinase, has been linked with greater invasion and metastasis in solid tumors. We have previously shown that ROCK-II is overexpressed at the advancing edge of colon cancers. The mechanism whereby ROCK-II contributes invasion, particularly in the setting of colon cancer, remains to be elucidated fully. To better understand its contribution, we evaluated ROCK-II expression in both non-malignant (NCM460 and IEC-6) and malignant (Caco-2 E, SW620, and HCT-116) intestinal epithelial cell lines grown in type I collagen scaffolds. Using multiphoton microscopy, we observed that ROCK-II localized to the actin cytoskeleton in non-malignant cells but localized to the cell periphery as focal collections with an absence of adjacent collagen in all colon cancer cell lines. By transmission electron microscopy, these collections corresponded with finger-like projections previously described as invadopodia. Immunogold staining with cortactin, matrix metalloprotease (MMP)-2, -9, and -13 confirmed that these were indeed invadopodia. To further link ROCK-II to colon cancer invasion, we treated non-malignant and malignant intestinal epithelial cell lines with ROCK-II siRNA and evaluated depth of invasion, proliferation, and MMP-2, -9, and -13 activities. The most striking effect was seen in the highly tumorigenic cell lines, SW620 and HCT-116, wherein ROCK-II knockdown resulted in a two-fold or more reduction in invasion. This reduction in invasion was not due to a decrease in cell proliferation, as a significant reduction in proliferation was only observed in the two non-malignant intestinal cell lines. Finally, both MMP-2 and -13 activities were significantly decreased in all colon cancer cell lines. Taken together, these data suggest for the first time that ROCK-II is a critical mediator of colon cancer cell invasion through its modulation of MMP-2 and -13 at the site of invadopodia but regulates proliferation in non-malignant intestinal cells.

Keywords:

ROCK-II, invadopodia, colon cancer, matrix metalloprotease, extracellular matrix, proliferation

Source : http://www.nature.com/labinvest/journal/v87/n11/abs/3700674a.html
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Lack of hepatocellular CD10 along bile canaliculi is physiologic in early childhood and persistent in Alagille syndrome

2007-10-20T12:29:00.000+07:00

Laboratory Investigation (2007) 87, 1138–1148; doi:10.1038/labinvest.3700677; published online 17 September 2007

Lack of hepatocellular CD10 along bile canaliculi is physiologic in early childhood and persistent in Alagille syndrome

Jane A Byrne^1,*, Natalie J Meara^2,†, Anne C Rayner², Richard J Thompson¹ and A S Knisely²

¹Division of Gene and Cell Based Therapy, King's College London School of Medicine, London, UK
²Institute of Liver Studies, King's College Hospital, London, UK

Correspondence: AS Knisely, MD, Institute of Liver Studies, King's College Hospital, Denmark Hill, London SE5 9RS, UK. E-mail: alex.knisely@kcl.ac.uk

^*Current address: Division of Cancer Sciences and Molecular Pathology, School of Medicine, University of Glasgow, Glasgow, UK.

^†Current address: Department of Pathology, Countess of Chester Hospital NHS Foundation Trust, Liverpool Road, Chester, UK.

Received 7 May 2007; Revised 17 August 2007; Accepted 17 August 2007; Published online 17 September 2007.

Abstract

Many tissues, including hepatobiliary cells, express neutral endopeptidase (CD10), encoded by MME. Serum neutral endopeptidase activity (NEA) has been recommended as a marker of cholestasis in adults but not in children with Alagille syndrome (AGS). We investigated ontogenic and disease-related differences in the expression of CD10. CD10 was found on canalicular surfaces of hepatocytes throughout the lobule in 16 adults and in 31 children aged 24 months, with and without cholestasis, but not in 39 children aged <24>24 months contained reduced levels of CD10. In contrast, AGS children and all controls expressed CD10 similarly on granulocytes. MME mRNA was found in the liver of children aged <24>MME mRNA levels were similar among all study subjects; however, liver MME mRNA levels were 6- to 140-fold less than in normal adults in all cholestatic subjects, including AGS children. Methylation of the MME promoter was not detected in the liver of AGS children. In conclusion, hepatocytes in early childhood physiologically lack immunohistochemically detectable CD10. Reduced MME mRNA in AGS is not due to MME promoter methylation. Liver CD10 in childhood appears to undergo reduced synthesis or rapid degradation, which persists in AGS. Absence of CD10 expression thus may limit NEA as a marker of cholestasis in young patients and in AGS.

Keywords:

Alagille syndrome, cholangiocyte, granulocyte, hepatocyte, immunohistochemistry, ontogeny

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Source : http://www.nature.com/labinvest/journal/v87/n11/abs/3700677a.html

Type IV collagen degradation in the myocardial basement membrane after unloading of the failing heart by a left ventricular assist device

2007-10-20T12:25:00.000+07:00

Laboratory Investigation (2007) 87, 1125–1137; doi:10.1038/labinvest.3700670; published online 17 September 2007

Type IV collagen degradation in the myocardial basement membrane after unloading of the failing heart by a left ventricular assist device

Annette H Bruggink¹, Matthijs F M van Oosterhout¹, Nicolaas de Jonge², Jack P M Cleutjens³, Dick F van Wichen¹, Joyce van Kuik¹, Marcel G J Tilanus¹, Frits H J Gmelig-Meyling⁴, Jan G van den Tweel¹ and Roel A de Weger¹

¹Department of Pathology, University Medical Center Utrecht, Utrecht, The Netherlands
²Department of Cardiology, University Medical Center Utrecht, Utrecht, The Netherlands
³Department of Pathology, University Maastricht, Maastricht, The Netherlands
⁴Department of Immunology, University Medical Center Utrecht, Utrecht, The Netherlands

Correspondence: AH Bruggink, MSc, Department of Pathology H04.312, University Medical Center Utrecht, Heidelberglaan 100, PO Box 85500, Utrecht GA 3508, The Netherlands. E-mail: a.h.bruggink@umcutrecht.nll

Received 5 February 2007; Revised 19 July 2007; Accepted 4 August 2007; Published online 17 September 2007.

Abstract

After left ventricular assist device (LVAD) support in patients with end-stage cardiomyopathy, cardiomyocytes decrease in size. We hypothesized that during this process, known as reverse remodeling, the basement membrane (BM), which is closely connected to, and forms the interface between the cardiomyocytes and the extracellular matrix, will be severely affected. Therefore, the changes in the myocardial BM in patients with end-stage heart failure before and after LVAD support were studied. The role of MMP-2 in this process was also investigated. Transmission electron microscopy showed that the BM thickness decreased post-LVAD compared to pre-LVAD. Immunohistochemistry indicated a reduced immunoreactivity for type IV collagen in the BM after LVAD support. Quantitative PCR showed a similar mRNA expression for type IV collagen pre- and post-LVAD. MMP-2 mRNA almost doubled post-LVAD (P<0.01).>in situ zymography. Furthermore, in situ hybridization/immunohistochemical double staining showed that MMP-2 mRNA was expressed in cardiomyocytes, macrophages, T-cells and endothelial cells. Taken together, these findings show reduced type IV collagen content in the BM of cardiomyocytes after LVAD support. This reduction is at least in part the result of increased MMP-2 activity and not due to reduced synthesis of type IV collagen.

Keywords:

basement membrane, LVAD support, MMP-2, reverse remodeling, type IV collagen

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Source : http://www.nature.com/labinvest/journal/v87/n11/abs/3700670a.html

Comprehensive identification of proteins in Hodgkin lymphoma-derived Reed–Sternberg cells by LC-MS/MS

2007-10-20T12:18:00.000+07:00

Laboratory Investigation (2007) 87, 1113–1124; doi:10.1038/labinvest.3700672; published online 17 September 2007

Comprehensive identification of proteins in Hodgkin lymphoma-derived Reed–Sternberg cells by LC-MS/MS

Jeremy C Wallentine¹, Ki Kwon Kim¹, Charles E Seiler III¹, Cecily P Vaughn², David K Crockett², Sheryl R Tripp², Kojo S J Elenitoba-Johnson^1,2 and Megan S Lim^1,2

¹Department of Pathology, University of Utah School of Medicine, Salt Lake City, UT, USA
²ARUP Institute for Clinical and Experimental Pathology, Salt Lake City, UT, USA

Correspondence: Dr MS Lim, MD, PhD, Department of Pathology, University of Michigan, M5242 Medical Science Building 1, 1301 Catherine Road, Ann Arbor, MI 48105, USA. E-mail: meganlim@med.umich.edu

Received 10 June 2007; Accepted 3 August 2007; Published online 17 September 2007.

Abstract

Mass spectrometry-based proteomics in conjunction with liquid chromatography and bioinformatics analysis provides a highly sensitive and high-throughput approach for the identification of proteins. Hodgkin lymphoma is a form of malignant lymphoma characterized by the proliferation of Reed–Sternberg cells and background reactive lymphocytes. Comprehensive analysis of proteins expressed and released by Reed–Sternberg cells would assist in the discovery of potential biomarkers and improve our understanding of its pathogenesis. The subcellular proteome of the three cellular compartments from L428 and KMH2 Hodgkin lymphoma-derived cell lines were fractionated, and analyzed by reverse-phase liquid chromatography coupled with electrospray ionization tandem mass spectrometry. Additionally, proteins released by Hodgkin lymphoma-derived L428 cells were extracted from serum-free culture media and analyzed. Peptide spectra were analyzed using TurboSEQUEST^® against the UniProt protein database (5.26.05; 188 712 entries). A subset of the identified proteins was validated by Western blot analysis, immunofluorescence microscopy and immunohistochemistry. A total of 1945 proteins were identified with 785 from the cytosolic fraction, 305 from the membrane fraction, 441 from the nuclear fraction and 414 released proteins using a minimum of two peptide identifications per protein and an error rate of <5.0%. Identification of proteins from diverse functional groups reflected the functional complexity of the Reed–Sternberg proteome. Proteins with previously reported oncogenic function in other cancers and from signaling pathways implicated in Hodgkin lymphoma were identified. Selected proteins without previously demonstrated expression in Hodgkin lymphoma were validated by Western blot analysis (B-RAF, Erb-B3), immunofluorescence microscopy (Axin1, Tenascin-X, Mucin-2) and immunohistochemistry using a tissue microarray (BRAF, PIM1). This study represents the first comprehensive inventory of proteins expressed by Reed–Sternberg cells of Hodgkin lymphoma and demonstrates the utility of combining cellular subfractionation, protein precipitation, tandem mass spectrometry and bioinformatics analysis for comprehensive identification of proteins that may represent potential biomarkers of the disease.

Keywords:

biomarker discovery, Hodgkin lymphoma, shotgun proteomics, tandem mass spectrometry, bioinformatics analysis

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Source : http://www.nature.com/labinvest/journal/v87/n11/abs/3700672a.html

A refined method for molecular typing reveals that co-occurrence of PrPSc types in Creutzfeldt–Jakob disease is not the rule

2007-10-20T12:13:00.000+07:00

Laboratory Investigation (2007) 87, 1103–1112; doi:10.1038/labinvest.3700676; published online 24 September 2007

A refined method for molecular typing reveals that co-occurrence of PrP^Sc types in Creutzfeldt–Jakob disease is not the rule

Silvio Notari¹, Sabina Capellari¹, Jan Langeveld², Armin Giese³, Rosaria Strammiello¹, Pierluigi Gambetti⁴, Hans A Kretzschmar³ and Piero Parchi¹

¹Dipartimento di Scienze Neurologiche, Università di Bologna, Bologna, Italy
²CIDC-Lelystad, Lelystad, The Netherlands
³Institut fuer Neuropathologie, Ludwig-Maximilians-Universitaet, Muenchen, Germany
⁴Institute of Pathology, CWRU, Cleveland, OH, USA

Correspondence: Dr P Parchi, MD, PhD, Dipartimento di Scienze Neurologiche, Università di Bologna, Via Foscolo 7, Bologna 40123, Italy. E-mail: parchi@neuro.unibo.it

Received 22 July 2007; Revised 16 August 2007; Accepted 16 August 2007; Published online 24 September 2007.

Abstract

Molecular typing in Creutzfeldt–Jakob disease (CJD) relies on the detection of distinct protease-resistant prion protein (PrP^Sc) core fragments, which differ in molecular mass or glycoform ratio. However, the definition and correct identification of CJD cases with a co-occurrence of PrP^Sc types remains a challenge. With antibodies recognizing a linear epitope in the octapeptide repeat PrP region, supposed to distinguish between the two major PrP^Sc isoforms (ie, types 1 and 2), it was recently shown that all type 2 cases display an associated band with a type 1 migration pattern, which led to the conclusion that multiple PrP^Sc types regularly coexist in CJD. We studied brain samples from 53 sporadic CJD and 4 variant CJD subjects using a high-resolution electrophoresis, a wide range of proteinase K (PK) activities, the 'type 1-selective' antibody 12B2, and several unselective antibodies. We found that the type 1-like band detected by 12B2 in all CJD subtypes associated with PrP^Sc type 2 is not a PK-resistant PrP^Sc core but rather matches the physicochemical properties of partially cleaved fragments, which result from the several PK cleavage sites included in the N-terminal portion of PrP^Sc. Furthermore, using gels with high resolution and a relatively high PK activity, we were able to increase the detection sensitivity of either type 1 or 2, when coexisting, to amount corresponding to 3–5% of the total PrP^Sc signal (ie, weak band of one type/total PrP^Sc). Our results show that there are many pitfalls associated with the use of 'type 1 selective' antibodies for CJD typing studies and that co-occurrence of PrP^Sc types in CJD is not the rule. The present results further validate the rationale basis of current CJD classification and the qualitative nature of molecular typing in CJD.

Keywords:

classification, prion, strain, typing, western blotting

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Source : http://www.nature.com/labinvest/journal/v87/n11/abs/3700676a.html

An orthotopic xenograft model of intraneural NF1 MPNST suggests a potential association between steroid hormones and tumor cell proliferation

2007-10-20T12:07:00.000+07:00

Laboratory Investigation (2007) 87, 1092–1102; doi:10.1038/labinvest.3700675; published online 17 September 2007

An orthotopic xenograft model of intraneural NF1 MPNST suggests a potential association between steroid hormones and tumor cell proliferation

George Q Perrin^1,2, Hua Li³, Lauren Fishbein³, Susanne A Thomson³, Min S Hwang⁴, Mark T Scarborough⁵, Anthony T Yachnis⁶, Margaret R Wallace^3,7, Thomas H Mareci⁸ and David Muir^1,2,9

¹Department of Neuroscience, College of Medicine, University of Florida, Gainesville, FL, USA
²Shands Cancer Center, College of Medicine, University of Florida, Gainesville, FL, USA
³Department of Molecular Genetics and Microbiology, College of Medicine, University of Florida, Gainesville, FL, USA
⁴Department of Biomedical Engineering, College of Medicine, University of Florida, Gainesville, FL, USA
⁵Department of Orthopaedics and Rehabilitation, College of Medicine, University of Florida, Gainesville, FL, USA
⁶Department of Pathology and Laboratory Medicine, College of Medicine, University of Florida, Gainesville, FL, USA
⁷Department of Pediatrics, Genetics Division, College of Medicine, University of Florida, Gainesville, FL, USA
⁸Department of Biochemistry and Molecular Biology, College of Medicine, University of Florida, Gainesville, FL, USA
⁹Department of Pediatrics, Neurology Division, College of Medicine, University of Florida, Gainesville, FL, USA

Correspondence: Dr GQ Perrin, PhD, Department of Neuroscience, College of Medicine, University of Florida, PO Box 100244, 1600 SW Archer Rd, Gainesville, FL 32610-0244, USA. E-mail: gperrin@ufl.edu

Received 4 May 2007; Revised 15 August 2007; Accepted 16 August 2007; Published online 17 September 2007.

Abstract

Malignant peripheral nerve sheath tumors (MPNST) are the most aggressive cancers associated with neurofibromatosis type 1 (NF1). Here we report a practical and reproducible model of intraneural NF1 MPNST, by orthotopic xenograft of an immortal human NF1 tumor-derived Schwann cell line into the sciatic nerves of female scid mice. Intraneural injection of the cell line sNF96.2 consistently produced MPNST-like tumors that were highly cellular and showed extensive intraneural growth. These xenografts had a high proliferative index, were angiogenic, had significant mast cell infiltration and rapidly dominated the host nerve. The histopathology of engrafted intraneural tumors was consistent with that of human NF1 MPNST. Xenograft tumors were readily examined by magnetic resonance imaging, which also was used to assess tumor vascularity. In addition, the intraneural proliferation of sNF96.2 cell tumors was decreased in ovariectomized mice, while replacement of estrogen or progesterone restored tumor cell proliferation. This suggests a potential role for steroid hormones in supporting tumor cell growth of this MPNST cell line in vivo. The controlled orthotopic implantation of sNF96.2 cells provides for the precise initiation of intraneural MPNST-like tumors in a model system suitable for therapeutic interventions, including inhibitors of angiogenesis and further study of steroid hormone effects on tumor cell growth.

Keywords:

neurofibromatosis, malignant peripheral nerve sheath tumor, angiogenesis, xenografts, orthotopic, steroid hormone

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Source : http://www.nature.com/labinvest/journal/v87/n11/abs/3700675a.html

Pathobiology of transforming growth factor bold italic beta in cancer, fibrosis and immunologic disease, and therapeutic considerations

2007-10-20T12:01:00.000+07:00

Laboratory Investigation (2007) 87, 1077–1091; doi:10.1038/labinvest.3700669; published online 27 August 2007

Pathobiology of transforming growth factor in cancer, fibrosis and immunologic disease, and therapeutic considerations

Gérald J Prud'homme¹

¹Department of Laboratory Medicine, St Michael's Hospital and University of Toronto, Toronto, ON, Canada

Correspondence: Dr GJ Prud'homme, Department of Laboratory Medicine, St Michael's Hospital, Room 2013CC, 30 Bond Street, Toronto, ON, Canada M5B1W8. E-mail: prudhommeg@smh.toronto.on.ca

Received 21 June 2007; Revised 1 August 2007; Accepted 1 August 2007; Published online 27 August 2007.

Abstract

Transforming growth factor (TGF-) is a highly pleiotropic cytokine that plays an important role in wound healing, angiogenesis, immunoregulation and cancer. The cells of the immune system produce the TGF-1 isoform, which exerts powerful anti-inflammatory functions, and is a master regulator of the immune response. However, this is context dependent, because TGF- can contribute to the differentiation of both regulatory (suppressive) T cells (Tr cells) and inflammatory Th17 cells. While TGF- might be underproduced in some autoimmune diseases, it is overproduced in many pathological conditions. This includes pulmonary fibrosis, glomerulosclerosis, renal interstitial fibrosis, cirrhosis, Crohn's disease, cardiomyopathy, scleroderma and chronic graft-vs-host disease. In neoplastic disease, TGF- suppresses the progression of early lesions, but later this effect is lost and cancer cells produce TGF-, which then promotes metastasis. This cytokine also contributes to the formation of the tumor stroma, angiogenesis and immunosuppression. In view of this, several approaches are being studied to inhibit TGF- activity, including neutralizing antibodies, soluble receptors, receptor kinase antagonist drugs, antisense reagents and a number of less specific drugs such as angiotensin II antagonists and tranilast. It might be assumed that TGF- blockade would result in severe inflammatory disease, but this has not been the case, presumably because the neutralization is only partial. In contrast, the systemic administration of TGF- for therapeutic purposes is limited by toxicity and safety concerns, but local administration appears feasible, especially to promote wound healing. Immunotherapy or vaccination stimulating TGF- production and/or Tr differentiation might be applied to the treatment of autoimmune diseases. The benefits of new therapies targeting TGF- are under intense investigation.

Keywords:

transforming growth factor , autoimmune, angiogenesis, cancer, inflammation, fibrosis

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Source : http://www.nature.com/labinvest/journal/v87/n11/abs/3700669a.html

Role of telomeres and telomerase in genomic instability, senescence and cancer

2007-10-20T11:54:00.000+07:00

Laboratory Investigation (2007) 87, 1071–1076. doi:10.1038/labinvest.3700673; published online 3 September 2007

Role of telomeres and telomerase in genomic instability, senescence and cancer

Yibin Deng¹ and Sandy Chang^1,2

¹Department of Cancer Genetics, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
²Department of Hematopathology, The University of Texas MD Anderson Cancer Center, Houston, TX, USA

Correspondence: Dr S Chang, MD, PhD, Department of Cancer Genetics, The University of Texas MD Anderson Cancer Center, Room S13.8136A, 1515 Holcombe Blvd., Houston, TX 77030, USA. E-mail: schang@mdanderson.org

Received 12 February 2007; Revised 10 August 2007; Accepted 10 August 2007; Published online 3 September 2007.

Abstract

Telomeres are ribonucleoprotein structures that protect the end of linear chromosomes from recognition as DNA double-stranded breaks and activation of a DNA damage response. Telomere-associated proteins also regulate telomerase, the protein responsible for maintaining telomere length. Loss of telomere function results from either alteration in the capping function at telomeres, or from progressive loss of telomeric repeats necessary to maintain proper telomeric structure. Dysfunctional telomeres activate p53 to initiate cellular senescence or apoptosis to suppress tumorigenesis. However, in the absence of p53, telomere dysfunction is an important mechanism to generate chromosomal instability commonly found in human carcinomas. Telomerase is expressed in the majority of human cancers, making it an attractive therapeutic target. Emerging anti-telomerase therapies that are currently in clinical trials might prove useful against some forms of human cancers.

Keywords:

telomeres, genomic instability, DNA damage, replicative senescence, tumorigenesis

Source : http://www.nature.com/labinvest/journal/v87/n11/abs/3700673a.html

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Miraculous Messages from Water

2007-09-19T01:34:00.000+07:00

Water has a very important message for us. Water is telling us to take a much deeper look at our selves. When we do look at our selves through the mirror of water, the message becomes amazingly, crystal, clear. We know that human life is directly connected to the quality of our water, both within and all around us.

The photographs and information in this article reflect the work of Masaru Emoto, a creative and visionary Japanese researcher. Mr. Emoto has published an important book, "The Message from Water," from the findings of his worldwide research If you have any doubt that your thoughts affect everything in, and around you, the information and photographs that are presented here, taken from the book of his published results, will change your mind and profoundly alter your beliefs, .From Mr. Emoto's work we are provided with factual evidence, that human vibrational energy, thoughts, words, ideas and music, affect the molecular structure of water, the very same water that comprises over seventy percent of a mature human body and covers the same amount of our planet. Water is the very source of all life on this planet, its quality and integrity are vitally important to all forms of life. The body is very much like a sponge and is composed of trillions of chambers called cells that hold liquid. The quality of our life is directly connected to the quality of our water.

Water is a very malleable substance. Its physical shape easily adapts to whatever environment is present. But its physical appearance is not the only thing that changes; its molecular shape also changes. The energy or vibrations of the environment will change the molecular shape of water. In this sense water not only has the ability to visually reflect the environment but it also molecularly reflects the environment.

Mr. Emoto has been visually documenting these molecular changes in water by means of his photographic techniques. He freezes droplets of water and then examines them under a dark field microscope that has photographic capabilities. His work clearly demonstrates the diversity of the molecular structure of water and the effect of the environment upon the structure of the water.

Snow has been falling on the earth for more than a few million years. Each snowflake, as we have been told, has a very unique shape and structure. By freezing water and taking a photograph of the structure, as Mr. Emoto has done, you get incredible information about the water.

Mr. Emoto has discovered many fascinating differences in the crystalline structures of water from many different sources and different conditions around the planet. Water from pristine mountain streams and springs show the beautifully formed geometric designs in their crystalline patterns. Polluted and toxic water from industrial and populated areas and stagnated water from water pipes and storage dams show definitively distorted and randomly formed crystalline structures.

Spring Water of Saijo, Japan

Spring Water of Sanbuichi

Yusui, Japan

Antarctic Ice

Fountain in Lourdes, France

Biwako Lake, the largest lake

at the center of Japan and

the water pool of the Kinki Region.

Pollution is getting worse

Yodo River, Japan

pours into the Bay of Osaka.
The river passes through most

of the major cities in Kasai

Fujiwara Dam

before offering a prayer

Fujiwara Dam

after offering a prayer

With the recent popularity in music therapy, Mr. Emoto decided to see what effects music has on the structuring of water. He placed distilled water between two speakers for several hours and then photographed the crystals that formed after the water was frozen.

Beethoven's Pastorale

Bach's " Air for the G string "

Tibet Sutra

Kawachi Folk Dance

Heavy Metal Music

After seeing water react to different environmental conditions, pollution and music, Mr. Emoto and colleagues decided to see how thoughts and words affected the formation of untreated, distilled, water crystals, using words typed onto paper by a word processor and taped on glass bottles overnight. The same procedure was performed using the names of deceased persons. The waters were then frozen and photographed.

Untreated Distilled Water

Love and Appreciation

Thank You

You Make Me Sick,

I Will Kill You

Adolph Hitler

Mother Teresa

These photographs show the incredible reflections of water, as alive and highly responsive to every one of our thoughts and emotions. It is quite clear that water easily takes on the vibrations and energy of its environment, whether toxic and polluted or naturally pristine, either within our selves or surrounding us in others and the environment.

Masaru Emoto's extraordinary work is an awesome display, and powerful tool, that can change our perceptions of ourselves and the world we live in, forever. We now have profound evidence that we can positively heal and transform ourselves and our planet by the thoughts we choose to think and the ways in which we put those thoughts into action.

Source from : http://www.wellnessgoods.com/messages.asp

Water Memory Effects Explored In New Issue Of Homeopathy Journal

2007-09-19T00:37:00.000+07:00

A special issue of the journal Homeopathy, journal of the Faculty of Homeopathy and published by Elsevier, on the 'Memory of Water' brings together scientists from around the world for the first time to publish new data, reviews and discuss recent scientific work exploring the idea that water can display memory effects. The concept of memory of water is important to homeopathy because it offers a potential explanation of the mechanism of action of very high dilutions often used in homeopathy.

Guest editor Professor Martin Chaplin of the Department of Applied Science at London South Bank University, remarks: "There is strong evidence concerning many ways in which the mechanism of this 'memory' may come about. There are also mechanisms by which such solutions may possess effects on biological systems which substantially differ from plain water."

The concept of the memory of water goes back to 1988 when the late Professor Jacques Benveniste published, in the international scientific journal Nature, claims that extremely high 'ultramolecular' dilutions of an antibody had effects in the human basophil degranulation test, a laboratory model of immune response. In other words, the water diluent 'remembered' the antibody long after it was gone. His findings were subsequently denounced as 'pseudoscience' and yet, despite the negative impact this had at the time, the idea has not gone away.

In this special issue of Homeopathy, scientists from the Czech Republic, France, Germany, Italy, Russia, USA as well as the UK present remarkably convergent views from groups using entirely different methods, indicating that large-scale structural effects can occur in liquid water, and can increase with time. Such effects might account for claims of memory of water effects.

Commenting on the special issue, Professor Chaplin said: "Science has a lot more to discover about such effects and how they might relate to homeopathy. It is unjustified to dismiss homeopathy, as some scientists do, just because we don't have a full understanding of how it works." In his overview he is critical of the 'unscientific rhetoric' of some scientists who reject the memory of water concept "with a narrow view of the subject and without any examination or appreciation of the full body of evidence."

Professor Chaplin and Dr Peter Fisher, editor-in-chief of the journal, agree that the current evidence brings us a step closer to providing an explanation for the claims made for homeopathy and that the memory of water, once considered a scientific heresy, is a reality. "These discoveries may have far reaching implications and more research is required," comments Dr Fisher.

Article adapted by Medical News Today from original press release.

Pediatrics in Review online

2007-09-15T03:01:00.000+07:00

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Electronic Journals of Bradford University

2007-09-14T02:42:00.000+07:00

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2007-09-14T02:28:00.000+07:00

The International Journal of Qualitative Methods is a peer reviewed journal published quarterly as a web-based journal by the International Institute for Qualitative Methodology at the University of Alberta, Canada, and its international affiliates. It is a multi-disciplinary, multi-lingual journal, free to the public.

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2007-09-14T02:23:00.000+07:00

EEPIS Journal

Journal online, http://journal.eepis-its.edu, wadah ilmiah untuk para penulis dan peneliti secara online. Judulnya adalah journal EEPIS yang seluruh prosesnya dilakukan secara online (submit, review, persetujuan, publikasi).

Journal Online juga memuat data jurnal - jurnal di PENS secara online dan memberikan fasilitas kepada user untuk melihat seluruh data jurnal, abstrak dan full paper secara online.Sampai saat ini jurnal online sudah tersedia untuk tahun 2001, 2002, 2003, 2004 dan 2005.

Biological technology

2007-09-14T01:52:00.000+07:00

Biological technology is technology based on biology, especially when used in agriculture, food science, and medicine. The United Nations Convention on Biological Diversity has come up with one of many definitions of biotechnology:^[1]

"Biotechnology means any technological application that uses biological systems, living organisms, or derivatives thereof, to make or modify products or processes for specific use."

Biotechnology is a popular term for the generic technology of the 21st century. Although it has been utilised for centuries in traditional production processes, modern biotechnology is only 50 years old and in the last decades it has been witnessing tremendous developments. Bioengineering is the science upon which all Biotechnological applications are based.With the development of new approaches and modern techniques, traditional biotechnology industries are also acquiring new horizons enabling them to improve the quality of their products and increase the productivity of their systems.

Before the 1970s, the term, biotechnology, was primarily used in the food processing and agriculture industries. Since the 1970s, it began to be used by the Western scientific establishment to refer to laboratory-based techniques being developed in biological research, such as recombinant DNA or tissue culture-based processes. In fact, the term should be used in a much broader sense to describe the whole range of methods, both ancient and modern, used to manipulate organic to reach the demands of human. So the term can be defined as, "The application of indigenous and/or scientific knowledge to the management of (parts of) microorganisms, or of cells and tissues of higher organisms, so that these supply goods and services of use to human beings.^[2]

There has been a great deal of talk - and money - poured into biotechnology with the hope that miracle drugs will appear. While there do seem to be a small number of efficacious drugs, in general the biotech revolution has not happened in the pharmaceutical sector. However, recent progress with monoclonal antibody based drugs, such as Genentech's Avastin suggest that biotech may finally have found a role in pharmaceutical sales.

Biotechnology combines disciplines like genetics, molecular biology, biochemistry, embryology and cell biology, which are in turn linked to practical disciplines like chemical engineering, information technology, and robotics.

N.C. Biotechnology Center Study Seeks Boost in State Support for Advanced Medical Technologies

2007-09-14T01:46:00.000+07:00

RESEARCH TRIANGLE PARK, NC | Posted on September 12th, 2007A strategic plan unveiled today by the North Carolina Biotechnology Center calls upon business, academic and civic leaders to boost the state's support for advanced medical technologies.

The plan calls for establishment of a North Carolina Center for Advanced Medical Technologies to develop the burgeoning business sector that includes diagnostics as well as therapeutics and encompasses such diverse specialties as biotechnology, engineering, nanotechnology and bioelectrics.

Teri Louden, president of The Louden Network of Chapel Hill, served as a consultant to the Biotechnology Center for this report. An experienced medical marketing executive and strategy consultant to the industry, she described her year-long study's findings at a forum at the Biotechnology Center sponsored by the Council for Entrepreneurial Development.

"We're facing a convergence of technologies and an aging population that's creating an explosion of opportunities in this new global sector," said Louden. "And that's why we need a Center for Advanced Medical Technologies even though we already have the world's first and finest Biotechnology Center. It will be the catalyst and support network we need to advance this technology sector from within, and also provide resources and services to those global scientists and companies who might like to move here."

Ken Tindall, senior vice president of science and business development at the Biotechnology Center, said advanced medical technologies is a sector being considered for development through the Centers of Innovation program.

"This strategic plan provides a framework for our state's world-class medical researchers, pharmaceutical manufacturers, biomedical engineers and other specialists who will define our future in advanced medical technologies," Tindall said.

It is sometimes difficult to find meaningful statistics on companies that fit the definition of advanced medical technology companies. Medical devices are part of the sector, but fast-changing applications and tools brought to the healing arts are also changing the language used to define and quantify it.

For perspective, however, the number of medical device companies doing business in North Carolina grew from 105 in 1996 to 142 in 2006, according to the report, which was prepared with additional support from the N.C. Biosciences Organization (NCBIO).

The report, "North Carolina's Strategic Plan for Advanced Medical Technologies," estimates medical device industry employment in North Carolina at 7,200, up some 17 percent from 6,179 a decade earlier. Average wages for medical device industry workers in 2006 were $40,648 per year, and the industry is forecast to bring $9.5 billion to North Carolina within the next two years.

Still, North Carolina lags behind California, Massachusetts, Minnesota, Florida, Pennsylvania, New York, New Jersey, Indiana, Texas and the territory of Puerto Rico in medical device industry employment.

Recent industry growth has been strong among start-up firms statewide, however. Between January of 1999 and December of 2006, advanced medical technologies companies in North Carolina have collectively raised more than $545 million in private and public equity from investors. Among these investments, $370 million were in medical device companies, $99 million in diagnostics firms, and $76 million in medical information technology businesses. During the same period, large firms paid more than $810 million to acquire emerging medical device companies founded in North Carolina.

"This study shows that advanced medical technologies are going to thrive in places where underlying technologies like biotechnology, nanotechnology, and information technology provide a solid foundation," said Sam Taylor, president of NCBIO. "We are blessed here in North Carolina to have great strengths in each of those fields, and a strong and growing medical device industry that is already building innovative new products based on their convergence."

The report says the state needs better access to specialized resources, however, such as managers and support companies with experience in medical device and advanced medical technologies regulation, marketing and reimbursement. Recruiting key personnel is among the report's leading objectives for future sector development efforts.

Daniel Pelak, president and CEO of InnerPulse here and co-chair of the advisory committee that developed the strategic plan, said the sector is one of the nation's fastest-growing during the past decade.

"North Carolina's historical strength in biotechnology and medical science uniquely qualifies the state to participate in this growth, said Pelak, an experienced entrepreneur in the industry who was CEO of Closure Medical when it was recently purchased by Johnson & Johnson. "The creation of the Advanced Medical Technology Center will provide the support network for existing growth companies that are pioneering life-saving technologies and help attract further investment to the state."

Besides Louden, Taylor, Pelak and Tindall, Biotechnology Center President and CEO Norris Tolson also participated in the release of the report.

read more..........

MIRACLE IN THE EYE

2007-09-13T05:00:00.000+07:00

Before you finish reading this sentence, approximately one hundred billion (100,000,000,000) operations will have been completed inside your eyes. However fantastic it may seem, you possess an example (two, in fact) of the Universe's ultimate technology. No scientist has ever come close to fully grasping it, let alone inventing anything remotely similar.

Whatever you have in your life is meaningful through your senses-vision and others. Your family, your house, your office, your friends and everything else in your surroundings, you quickly identify thanks to your vision. Without eyes, you could never get a quick, complete sense of everything that's happening around you. Without them, you could never imagine colors, forms, scenes, human faces, or what the word beauty means. But you do have eyes, and thanks to them, you can now read these printed words before you.

Nor does the act of vision cost you very much effort. To see an object, all you have to do is to turn your gaze at it. You don't need to bother giving "project, capture, and analyze" orders to your eyes, the components inside them, the optical nerves running to the back of your brain, nor to the brain itself. You need only look, just like the rest of the billions of creatures who have ever lived on our planet. Without having to work out the optical measurements, your eye's lens can focus onto distant objects. Without needing to accurately compute the precise contractions of various muscles surrounding the lens, you only desire to see, and within a fraction of a second, that process is carried out for you. Like many people, you may never have realized what a miracle it is that thousands of independent processes can operate in a perfect harmony to enable you to see.

Nor did you have to struggle to develop a pair of those wonderful instruments. At birth, your eyes came as standard equipment, with free installation and, unless you had a particular defect, in perfect working order. Since then, you're not likely to have felt any urge to ask the kind of questions you might upon receiving an expensive, anonymous gift, such as "Why did I get this?" or, "Who sent this to me?" or, "Exactly what do they want from me in return?." Be assured that the Creator, Who lent you this blessing, will call you to account when the contract ends-which is sooner than you imagine.

Those who best understand how irreplaceable this blessing is, are people who lose their eyesight later in life. In the possible event that you are struck blind, your long list of lifetime plans and ambitions will be sidelined by just one wish: To regain your lost eyesight.

Had you been blind all your life, since birth, and after an operation, you could see all of a sudden, the reverse would be no less dramatic. Without a doubt, no gift in the world would seem more valuable. You would experience no greater happiness than at the moment your bandages were removed, and on the days that followed.

At this very moment, if you are not acknowledging the unique blessing of your eyes to the Gracious One Who has granted it to you, then you are being deeply ungrateful-a state of mind that, unfortunately, is shared by a substantial part of humanity.

Say: "It is He Who brought you into being and gave you hearing, sight and hearts. What little thanks you show!" (Qur'an, 67: 23)

Evolution Back on the Ropes

How did such a vital sense like seeing come to be? How could a formerly nonexistent concept-seeing-suddenly appear? Let's generalize the question by widening our scope. How did man come to existence in the first place, complete with his five senses, brains, internal organs, limbs, and with a soul and a functioning body?

Anyone with common sense can tell you that life is the work of a superior and flawless creation. Rejecting this clear truth, the theory of evolution, provides "coincidence" as its answer to this question. Evolutionists claim that all living things in this world, past and present, came to evolve through a chain of countless coincidences, with never an original creation to start the process. But this claim defies all laws of logic and science, inasmuch as it's impossible for lifeless matter to create an organism. The theory of evolution tries to explain the universe's flawless nature through coincidental happenings, but science has been proven it wrong in every way. Scientific proof has shown not only how evolutionary claims are unreasonable and unscientific, but also, has revealed how evolutionists have forged their evidence. Science has demonstrated that life cannot possibly be explained through coincidences, since it is the work of a superior design. The Creator of this flawless design is God, Who created the entire universe.

Despite this unavoidable truth, today 's dominant academic establishments and media conglomerates collaborate in a joint effort to uphold the theory of evolution. Their standard technique is to issue a news bulletin that some recently excavated skull proudly provides a link heretofore missing of the grand evolutionary chain. Not only are there any evolutionary chains to complete, but the excavations do not reveal anything closely resembling the long-awaited figments of evolutionists' imagination-such as the half-fish, half-reptile or the half-reptile, half-bird. Yet their press-release hype leaves the impression that evolution as a whole has been already proven, except for a few random details regarding the lineage from ape to human.

Of course, there is a reason behind the evolutionists' constant emphasis on excavating skulls. Throughout the history of the world, there have been thousands of species of ape, of all shapes and sizes, of which 97 per cent are now extinct. It is simple child's play to array the skulls of extinct apes on a long table according to cranial volume or one structural characteristic and declare this lineup to be "the evolutionary chain joining ape and man." The evolutionist's basic toolkit consists of fossil forgeries, false lineages, and creative drawings of ape-men that have little to do with scientific evidence.

In reality, evolution's supposedly strong progression crumbles at its beginning stage of microbiology. The most probing questions about the emergence of complex organelles again fall on deaf ears. No wonder the evolutionists avoid discussing these fundamental subjects, except occasionally by pretending to explain them by piling up numerous technical details that, in the aggregate, hardly constitute an answer.

The eye, the subject of this book, is one of those organs of the body that have kept evolutionists on the ropes ever since Darwin, who himself confessed, "I remember well the time when the thought of the eye made me cold all over."1 A close examination of the eye's structure and functions will make it clear why evolutionists have felt compelled to avoid it. The eye's complex structure has several distinct components and systems. An amazing scope of distinctly different functions are realized individually, but only as a result of harmonious cooperation between all of these components and systems. If even one of them is missing or fails to cooperate, the eye can't perceive images. This is a Catch 22 for the evolutionists, who hold that all body parts have emerged gradually by themselves. That the eye can only function as a whole only when all its every system and component are present and intact rules out any such gradual formation.

To illustrate this crucial point, let us give a true-life example. An eyeball that does not secrete teardrops to lubricate itself will dry up and eventually go blind. Tears, with their antiseptic properties, also protect the eye against microbes. The evolutionists do not even want to consider the fundamental question of how the eye, which would desiccate within hours without tear secretion, could have persisted for millions of years before tear glands had yet to emerge via the evolutionary progression. For the evolutionist camp, insult is added to injury when they must account for the fact that for the eye to accomplish its function, it requires a full body, intact with its systems and organs-components and tissues such as the cornea, retina, conjunctiva, iris, pupil, lens, choroid, eyelid, and the eye muscles. In addition, vision requires the brain's complex visual area and the amazing neural networks connecting the eye to the brain. All of these subsystems feature structures that are far too complex and specialized to have ever emerged by chance.

Of these components, if only one-the lens, for example-were missing, the eye would become a useless lump of tissue. Again, it would again be rendered useless if any two of them-for example, the pupil and the lens, exchanged places. In short, the eye's structure is the result of a very special planning. These components' harmonious coexistence and cooperation, which are impossible to have appeared by themselves as a result of accidents, have one single valid and logical explanation: Each of the eye's components is created with supreme intelligence, which belongs to God.

Accepting such an obvious truth is the first step that leads to a person's eternal life. This book, along with displaying the truth of creation, intends to guide you in taking those steps towards your salvation.

to be continoude ........

The Miracle In The Ant

2007-09-13T04:55:00.000+07:00

Preface

http://api.fmanager.net/api_v1/functions/thumb.php?image=http://207.44.240.34/files/book/resimler/TMITAB.jpg&width=100In this book we are going to tell you about a creature that you know quite well, that you meet everywhere without actually giving it much attention, that is highly skillful, highly social and highly intelligent - "The Ant". Our aim is to review the lives full of miracles of these minute creatures that are never of any significance in our daily lives.

Technology, collective work, military strategy, advanced communications network, an astute and rational hierarchy, discipline, perfect city planning… These are fields where human beings may not always be successful enough, but where the ants always are. When you look at these creatures, which are fully armed to defeat tough rivals and to endure the difficult conditions of nature, you may think that all of them are identical. However, each species of the ant genus – and there are thousands of them – has, in fact, different characteristics. We believe that these creatures that have the highest population in the world may open up new horizons for us within the framework of the characteristics referred to above. This book will reveal to us the special and marvelous world of ants. We shall witness the things these ant communities succeed with their tiny bodies and witness that there is absolutely no difference between their fossils, the oldest of which is about 80 million years old, and their counterparts living today, that run to approximately 8800 species.

As we explore the special world of ants, this perfect system will earn our admiration and increase the need for thinking and investigating. At the same time, we shall see the mistakes in the theory of evolution and witness Allah's immaculate creation, which is a tremendously important work. In the Qur'an, the type of person who thinks about nature and thus recognizes the omnipotence of Allah is praised as a model for those who believe. The verses below explain this point fully:

In the creation of the heavens and the earth, and the alternation of night and day, there are indeed signs for men of understanding: men who celebrate the praises of Allah, standing, sitting, and lying down on their sides, and contemplate the wonders of creation in the heavens and the earth, (saying): "Our Lord! You have not created all this in vain! Glory be to You! Give us salvation from the penalty of the Fire."(Surat Al'Imran:190-191)

We hope that this book causes its readers to think more deeply on and to feel admiration for the superior power and unequaled art of creation of Allah, Who has made all things.

to be continoude..........

Tuberculosis 2007

2007-09-10T04:27:00.001+07:00

Buku yang mengupas tentang Tuberculosis selama tahun 2007. Buku ini sangat baik untuk pedoman para mahasiswa yang mengambil jurusan Kedikteran, Kesehatan ataupun jurusan Biologi.

Di dalam buku ini dibahas

How to Write Scientific Journal

2007-09-09T01:18:00.000+07:00

Why a Scientific Format?

The scientific format may seem confusing for the beginning science writer due to its rigid structure which is so different from writing in the humanities. One reason for using this format is that it is a means of efficiently communicating scientific findings to the broad community of scientists in a uniform manner. Another reason, perhaps more important than the first, is that this format allows the paper to be read at several different levels. For example, many people skim Titles to find out what information is available on a subject. Others may read only titles and Abstracts. Those wanting to go deeper may look at the Tables and Figures in the Results, and so on. The take home point here is that the scientific format helps to insure that at whatever level a person reads your paper (beyond title skimming), they will likely get the key results and conclusions.

Jurnal Ilmiah

2007-08-30T01:05:00.000+07:00

A. Pengertian Jurnal Ilmiah

Jurnal adalah terbitan berkala yang berbentuk pamflet berseri berisi bahan yang sangat diminati orang saat diterbitkan . Bila dikaitkan dengan kata ilmiah di belakang kata jurnal dapat terbitan berarti berkala yang berbentuk pamflet yang berisi bahan ilmiah yang sangat diminati orang saat diterbitkan. (Buku Pegangan Gaya Penulisan, penyunting dan penerbitan Karya Ilmiah Pegangan Gaya Penulisan, Penyunting dan Penerbitan Karya Ilmiah Indonesia, karya Mien A. Rifai, Gajah Mada Uneversity, 1995, h.57-95).

B. Macam Dan Jenis Jurnal

Ada beberapa jenis penerbitan berkala, selain jurnal , yaitu Majalah, Bulletin, Warkat Warta.
Majalah adalah terbitan berkala yang bukan harian, setiap keluar diberi halaman terpisah, biasanya diidentifikasi dengan tanggal dan bukan nomor berseri.
Bulletin adalah berkala resmi yang dikeluarkan lembaga atau organisasi profesi ilmiah serta memuat berita, hasil dan laporan kegiatan dalam satu bidang.
Warkat Warta, adalah terbitan pendek berisi berita, termasuk kemejuan keilmuan yang berisi catatan singkat yang mengutarakan materi secara umum dan tidak mendalam. (lihat Mien A. Rifai h.57-59).
Selain itu, dari sisi teknis isi ada tiga macam berkala ilmiah yaitu pertama majalah teknis ilmiah, kedua berkala semi ilmiah dan ketiga berkala sekunder.
Majalah teknis ilmiah merupakan majalah yang memuat hasil dan temuan baru penelitihan. Berkala ini biasanya sebagai sarana untuk komonikasi para pakar yang terspesialisasi.
Berkala semi ilmiah, yaitu berkala yang memuat tulisan teknis dengan cakupan yang bersifat siklopedia dan ditujukan bagi mereka yang bukan ahli atau spesialis dalam bidang yang dimaksud.
Berkala sekunder berisi abstrak atau ringkasan majalah primer yang sering disebut pula berkala penyari (abstracting Jurnal).
Selain itu, untuk keperluan pendidikan ada pula yang disebut berkala tinjauan yang memuat berbagai artikel ilmiah sejenis yang terbit beberapa tahun terakhir untuk memberikan gambaran kemejuan menyeluruh suatu topic (lihat Mien A. Rifai, h.59).
Berdasarkan pengertian, macam dan jenis tersebut diatas, didalampedoman ini dimaksudkan dengan jurnal ilmiah adalah terbitan berkala yang berisi kajian-kajian ilmiah yang spesifik dan dalam bidang tertentu.

Selengkapnya baca ........