How cells know when it’s time to eat themselves
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Researchers at the University of California, San Diego School of Medicine have identified a molecular mechanism regulating autophagy, a fundamental stress response used by cells to help ensure their survival in adverse conditions.
The findings are published online in the January 17 issue of Cell.
Senior author Kun-Liang Guan, PhD, a professor of pharmacology at UC San Diego Moores Cancer Center, and colleagues report that an enzyme called AMPK, typically involved in sensing and modulating energy use in cells, also regulates autophagic enzymes.
Autophagy, which derives from the Greek words for “self” and “eat,” is triggered to protect cells when times are tough, such as when cells are starved for nutrients, infected or suffering from damaged organelles, such as ribosomes and mitochondria. Much like the human body in freezing conditions will reduce operations in extremities to preserve core temperatures and organ functions, cellular autophagy involves the degradation and synthesis of some internal cellular elements to ensure survival of the whole.
NTU study looks at national attitudes towards homosexuals
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Attitudes of Singaporeans and permanent residents toward gays and lesbians although sharply polarised and predominantly negative, have shifted slightly over a five-year span to become a little more favourable. This was found by a research team from the Wee Kim Wee School of Communication and Information at Nanyang Technological University (NTU).
A nationally representative survey found that people with higher levels of education and freethinkers tend to have more positive attitudes. Those who had higher interpersonal contact with gay men and lesbians and watched more films and television shows with homosexual characters were also likely to express more positive attitudes toward gays and lesbians, and to show greater acceptance.
“This study is a continuation of an earlier one in 2005, which was initiated to provide a nationally representative and objective examination of public attitudes toward homosexuality in Singapore and to contribute to scholarship on homosexuality in Asia. By investigating some of the predictors of attitudes towards lesbians and gay men, it can help to inform public debate and guide future policy recommendations,” said Professor Benjamin Detenber, Chair of the Wee Kim Wee School of Communication and Information, who led a team of researchers to conduct this study in early 2010.
The study of 959 adult Singaporeans and permanent residents (PRs) found that while there has been a slight change in attitudes towards lesbians and gays in Singapore between 2005 and 2010, the change is significant, as it suggests a temporal shift in Singaporeans’ values and views about homosexuals.
Fluid from Pap test used to detect ovarian, endometrial cancers
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Using cervical fluid collected from routine Pap smears, U.S. researchers were able to spot genetic changes caused by both ovarian and endometrial cancers, offering promise for a new kind of screening test for these deadly cancers.
Experts say that although the test has tremendous potential, it is still years from widespread use. But if proven effective with more testing, it would fill a significant void.
Currently, there are no tests that can reliably detect either ovarian or endometrial cancer, which affects the uterine lining. Research teams have been trying for several years to find a screening test that could identify these cancers early, when there is a better chance of a cure.
Disappearing bacterium may protect against stroke
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A new study by NYU School of Medicine researchers reveals that an especially virulent strain of the gut bacterium Helicobacter pylori (H. pylori) isn’t implicated in the overall death rate of the U.S. population, and may even protect against stroke and some cancers. The findings, based a nationwide health survey of nearly 10,000 individuals over a period of some 12 years, are published online, January 9, in the journal Gut.
Those individuals carrying the most virulent strain of H. pylori, the study found, had a 55 percent reduced risk of deaths from stroke compared with their counterparts who were not infected with H. pylori. Participants with the most virulent strain also had a 45 percent reduced risk of death from lung cancer.
These surprising findings emerged from an analysis by Yu Chen, PhD, MPH, associate professor of population health and environmental medicine, and Martin J. Blaser, MD, professor of internal medicine and professor of microbiology, of individuals who participated in a national survey designed to assess the health and nutritional status of adults and children in the United States. Previous studies by Dr. Blaser have confirmed the bacterium’s link to gastric diseases ranging from gastritis to stomach cancer. He and Dr. Chen have more recently shown that H. pylori may protect against childhood asthma. The most virulent H. pylori strains have a gene called cagA.
“The significance of this study is that this is a prospective cohort of participants representative of the U.S. population with a long follow-up,” says Dr. Chen. “We studied both the overall H. pylori as well as cagA strain of H. pylori, which is more interactive with the human body. We found that H. pylori is not related to the risk of death from all causes, despite it being related to increased risk of death from gastric cancer.”
Cellular fuel gauge may hold the key to restricting cancer growth
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Researchers at McGill University have discovered that a key regulator of energy metabolism in cancer cells known as the AMP-activated protein kinase (AMPK) may play a crucial role in restricting cancer cell growth. AMPK acts as a “fuel gauge” in cells; AMPK is turned on when it senses changes in energy levels, and helps to change metabolism when energy levels are low, such as during exercise or when fasting. The researchers found that AMPK also regulates cancer cell metabolism and can restrict cancer cell growth.
The discovery was made by Russell (Rusty) Jones, an assistant professor at McGill’s Goodman Cancer Research Centre and the Department of Physiology, Faculty of Medicine. Jones along with his team is the first to show that AMPK can act as a tumour suppressor in animals. The research will be published December 27 in the journal Cell Metabolism.
“Cancer is a disease in which cells lose their normal restraints on growth and start to divide uncontrollably. But, in order for cells to grow quickly they need enough energy to complete the task,” Jones explained. “AMPK acts like the fuel gauge in your car – it lets the body know when energy levels are low, and stops cell growth until there is enough gas in the tank. We wanted to see if this fuel gauge could affect the development and progression of cancer. We found that mice lacking AMPK developed tumours faster, suggesting that AMPK is important for keeping tumour development in check, at least for some types of cancer.” For this study, Jones’ team focused specifically on a type of blood cancer known as lymphoma. They discovered that the protein Myc, which is activated in more than half of all cancers, could promote lymphoma more rapidly when mice were deficient for AMPK.
Steroid hormone receptor prefers working alone to shut off immune system genes
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Researchers at Emory University School of Medicine have obtained a detailed molecular picture that shows how glucocorticoid hormones shut off key immune system genes.
The finding could help guide drug discovery efforts aimed at finding new anti-inflammatory drugs with fewer side effects.
The results are scheduled for publication Sunday, Dec. 9 by the journal Nature Structural & Molecular Biology.
Synthetic glucocorticoid hormones - for example, prednisone and dexamethasone - are widely used to treat conditions such as allergies, asthma, autoimmune diseases and cancer. They mimic the action of the natural hormone cortisol, which is involved in the response to stress and in regulating metabolism and the immune system. For this reason, synthetic glucocorticoids have a variety of severe side effects such as increased blood sugar and reduced bone density.
Glowing fish shed light on metabolism
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A tiny, translucent zebrafish that glows green when its liver makes glucose has helped an international team of researchers identify a compound that regulates whole-body metabolism and appears to protect obese mice from signs of metabolic disorders.
Led by scientists at the University of California, San Francisco (UCSF), the work demonstrates how a fish smaller than a grain of rice can help screen for drugs to help control obesity, type 2 diabetes and other metabolic disorders, which affect a rising 34 percent of American adults and are major risk factors for cardiovascular disease.
Described this week in the journal Nature Chemical Biology, the new compound emerged from a panel of 2,400 medications and drug-like compounds tested in the zebrafish. The test was designed to identify key regulators of “fasting metabolism”- a state most people face every day after the lingering remnants of their long-digested meals pass slowly down their digestive tract.
Fasting metabolism is the body’s way of fulfilling its energy needs between meals by turning to fat and other stored sources. It involves a carefully balanced and coordinated cascade of reactions that see numerous genes in various tissues kick into action and do things like burn fat.
Policy considerations pose options for leaders to reduce costly disparities in diabetes
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As newly elected or reelected national leaders consider paths forward for continued implementation of the Affordable Care Act, an innovative, locally-implemented program focused on reducing disparities in diabetes is releasing a new set of policy considerations to help inform decisions on national health policy.
The Alliance to Reduce Disparities in Diabetes, a national program launched and supported by The Merck Company Foundation, released “Policy Considerations That Make the Link,” that offers policymakers options for ways to advance changes to overcome the systemic and structural barriers that have blocked the ability to deliver and sustain effective diabetes care to those most in need.
“The document connects the on-the-ground experiences of the Alliance grantees with the issues facing national decision makers as they consider ways to get more value, quality, efficiency and innovation into our health care system,” Noreen Clark, PhD, Director of the Alliance’s National Program Office said.
The considerations pose a series of questions surrounding the identified need to realign financial incentives affecting health systems, providers and patients as a mechanism for reducing disparities in diabetes.
10-minute ‘tension tamer’ can help reduce stress and improve sleep
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A simple, 10-minute stress reduction technique could help to relieve stress, improve sleep quality, and decrease fatigue. Researchers from Walter Reed National Military Medical Center, Bethesda, Maryland, attempted to determine the effect of a brief, stress reduction technique, the 10-minute Tension Tamer, on improvement of stress levels and sleep parameters in 334 patients in a heart health program. After a 30-minute introductory workshop, subjects were given instruction and guided opportunities to practice 10-minute Tension Tamers over the course of four 30-minute visits with a stress management specialist. This brief technique, encouraged at bedtime, involves deep breathing and imagery using the subject’s personal preference. Of the patients, 65% improved their perceived stress by 6.6 points; while those not improving showed worsened stress levels by 4.6 points. Improvers also reported better sleep quality, decreased sleep latency, and decreased fatigue. This study was presented during CHEST 2012, the annual meeting of the American College of Chest Physicians, held October 20 – 25, in Atlanta, Georgia.
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‘Elbow test’ may predict sleep apnea
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Have you ever been “elbowed” by your bed partner because you were snoring? If yes, new research says you could have obstructive sleep apnea (OSA). Prior to polysomnography testing, researchers from the University of Saskatchewan asked 124 patients two questions: (1) Does your bed-partner ever poke or elbow you because you are snoring; and (2) Does your bed-partner ever poke or elbow you because you have stopped breathing? Answering ‘yes’ to being awakened for snoring or apneic spells increased the likelihood of an apnea-hypopnea index (AHI) >5/h (indicating at least mild OSA) compared with ‘no.’ Analysis also showed that as disease severity increased, patients were more likely to be awakened for snoring and apneic spells. Researchers conclude that asking these two simple questions could significantly improve the pretest prediction of a diagnosis of OSA. This study was presented during CHEST 2012, the annual meeting of the American College of Chest Physicians, held October 20 – 25, in Atlanta, Georgia.
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Italy court ruling links mobile phone use to tumor
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Italy’s supreme court has upheld a ruling that said there was a link between a business executive’s brain tumor and his heavy mobile phone usage, potentially opening the door to further legal claims.
The court’s decision flies in the face of much scientific opinion, which generally says there is not enough evidence to declare a link between mobile phone use and diseases such as cancer and some experts said the Italian ruling should not be used to draw wider conclusions about the subject.
“Great caution is needed before we jump to conclusions about mobile phones and brain tumors,” said Malcolm Sperrin, director of medical physics and clinical engineering at Britain’s Royal Berkshire Hospital.
Discovery of gatekeeper nerve cells explains the effect of nicotine on learning and memory
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Swedish researchers at Uppsala University have, together with Brazilian collaborators, discovered a new group of nerve cells that regulate processes of learning and memory. These cells act as gatekeepers and carry a receptor for nicotine, which can explain our ability to remember and sort information.
The discovery of the gatekeeper cells, which are part of a memory network together with several other nerve cells in the hippocampus, reveal new fundamental knowledge about learning and memory. The study is published today in Nature Neuroscience.
The hippocampus is an area of the brain that is important for consolidation of information into memories and helps us to learn new things. The newly discovered gatekeeper nerve cells, also called OLM-alpha2 cells, provide an explanation to how the flow of information is controlled in the hippocampus.
“It is known that nicotine improves cognitive processes including learning and memory, but this is the first time that an identified nerve cell population is linked to the effects of nicotine”, says Professor Klas Kullander at Scilifelab and Uppsala University.
‘Disgusted’ Rats Teaching Scientists About Nausea, Work May Lead to New Cancer Treatments
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Nausea is a common and distressing side effect of many drugs and treatments. Unlike vomiting, nausea is not well understood, but new research by University of Guelph scientists may soon change that.
Guelph PhD student Katharine Tuerke, neuroscience researcher Cheryl Limebeer and Prof. Linda Parker in the Department of Psychology believe they’ve found the mechanism in the brain that is responsible for the sensation of nausea – with the help of some “disgusted” rats.
Their study was published this week in Journal of Neuroscience.
“Although everyone has experienced nausea at some point, its neurobiology is poorly understood due to a lack of animal models,” said Parker, who holds the Canada Research Chair in Behavioural Neuroscience.
Cedars-Sinai study sheds light on bone marrow stem cell therapy for pancreatic recovery
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Researchers at Cedars-Sinai’s Maxine Dunitz Neurosurgical Institute have found that a blood vessel-building gene boosts the ability of human bone marrow stem cells to sustain pancreatic recovery in a laboratory mouse model of insulin-dependent diabetes.
The findings, published in a PLOS ONE article of the Public Library of Science, offer new insights on mechanisms involved in regeneration of insulin-producing cells and provide new evidence that a diabetic’s own bone marrow one day may be a source of treatment.
Scientists began studying bone marrow-derived stem cells for pancreatic regeneration a decade ago. Recent studies involving several pancreas-related genes and delivery methods – transplantation into the organ or injection into the blood – have shown that bone marrow stem cell therapy could reverse or improve diabetes in some laboratory mice. But little has been known about how stem cells affect beta cells – pancreas cells that produce insulin – or how scientists could promote sustained beta cell renewal and insulin production.
Vitamin D deficiency ups heart disease risk
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Low levels of vitamin D are associated with a markedly higher risk of heart attack and early death, according to a new research.
The study involved more than 10,000 Danes and was conducted by the University of Copenhagen and Copenhagen University Hospital.
Vitamin D deficiency has traditionally been linked with poor bone health. However, the results from several population studies indicate that a low level of this important vitamin may also be linked to a higher risk of ischemic heart disease, a designation that covers heart attack, coronary arteriosclerosis and angina. Other studies show that vitamin D deficiency may increase blood pressure, and it is well known that high blood pressure increases the risk of heart attack.
