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News 04 march 2009

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The Controversy about a Possible Relationship between Mobile Phone Use and Cancer

Methodologic considerations revealed that three important conditions for epidemiologic studies to detect an increased risk are not met: a) no evidence-based exposure metric is available ; b) the observed duration of mobile phone use is generally still too low ; c) no evidence-based selection of end points among the grossly different types of neoplasias is possible because of lack of etiologic hypotheses. Concerning risk estimates, selection bias, misclassification bias, and effects of the disease on mobile phone use could have reduced estimates, and recall bias may have led to spuriously increased risks. The overall evidence speaks in favor of an increased risk, but its magnitude cannot be assessed at present because of insufficient information on long-term use.

The Synergistic Toxicity of Pesticide Mixtures

We observed addition and synergism, with a greater degree of synergism at higher exposure concentrations. Several combinations of organophosphates were lethal at concentrations that were sublethal in single-chemical trials. Conclusion: Single-chemical risk assessments are likely to underestimate the impacts of these insecticides on salmon in river systems where mixtures occur. Moreover, mixtures of pesticides that have been commonly reported in salmon habitats may pose a more important challenge for species recovery than previously anticipated.

Developmental Exposure to Polychlorinated Biphenyls Interferes with Experience

Developmental exposure to PCBs interferes with normal patterns of dendritic growth and plasticity, and these effects may be linked to changes in RyR expression and function. These findings identify PCBs as candidate environmental risk factors for neurodevelopmental disorders, especially in children with heritable deficits in calcium signaling.

Cats' Eye Diseases Genetically Linked to Diseases in Humans

About one in 3,500 people are affected with retinitis pigmentosa (RP), a disease of the retina's visual cells that eventually leads to blindness. Now, a University of Missouri researcher has identified a genetic link between cats and humans for two different forms of RP. This discovery will help scientists develop gene-based therapies that will benefit both cats and humans. "The same genetic mutations that cause retinal blindness in humans also cause retinal blindness in cats," said Kristina Narfstrom, the Ruth M. Kraeuchi-Missouri Professor in Veterinary Ophthalmology in the MU College of Veterinary Medicine. "Now, cats with these mutations can be used as important animal models to evaluate the efficiency of gene therapy. In addition, the eye is an ideal organ to use as we examine the potential of gene replacement intervention because it offers an accessible and confined environment."

'Pre-Diabetics' Face Heightened Risk of Heart Disease

Older adults who have impaired glucose tolerance but who are not considered diabetic are at elevated risk for heart disease and may benefit from preventive therapies, according to a new study conducted by researchers at Albert Einstein College of Medicine of Yeshiva University. The study, published in the Journal of Clinical Endocrinology & Metabolism, was led by Jill P. Crandall, M.D., associate professor of clinical medicine and director of the Diabetes Clinical Trials Unit at Einstein. Diabetes becomes increasingly common with age. An estimated 37 million Americans over the age of 65 have diabetes, almost one-quarter of that population. Another 20 to 30 percent of seniors, an estimated 7.5 to 11.1 million, are not clinically diabetic but have impaired glucose tolerance, which is considered a form of "pre-diabetes." "In most cases, this mild form of high blood glucose causes no symptoms and is often overlooked by both doctors and patients, but studies have shown that it may be associated with increased risk of heart disease," says Dr. Crandall. "The purpose of this study was to explore the cardiovascular risk profile of older adults with pre-diabetes."

Penn Researchers Identify Source of Cells that Spur Aberrant Bone Growth

Researchers at the University of Pennsylvania School of Medicine and the University of Connecticut have pinpointed the source of immature cells that spur misplaced bone growth. Unexpectedly, the major repository of bone-forming cells originates in blood vessels deep within skeletal muscle and other connective tissues, not from muscle stem cells themselves. The work also shows that cells important in the inflammatory response to injury trigger skeleton-stimulating proteins to transform muscle tissue into bone.

New study shows how spikes in nitrite can have

A new study provides insight into how a short burst in nitrite can exert lasting beneficial effects on the heart, protecting it from stress and assaults such as heart attacks. In this study, just published in Circulation Research, researchers at Boston University School of Medicine have demonstrated for the first time that short elevations in circulating levels of this simple anion are sufficient to have a lasting impact on the heart by modulating its oxidation status and its protein machinery. Nitrite, an oxidation product of the ubiquitous short-lived cell signaling molecule, nitric oxide (NO), was until recently thought to be biologically inert at the relatively low levels found in the body. Traces of nitrite are present in our diet and significant amounts are continuously produced from nitrate, another oxidation product of NO and a constituent of green, leafy vegetables. The suspicion that high levels of nitrite and nitrate may cause cancer, as well as concerns about their risk to compromise the ability of red blood cells to deliver oxygen to tissues, have led to strict regulations aimed at limiting our exposure to these substances through drinking water and food products. In the past few years, however, multiple research groups have shown that low concentrations of nitrite exert numerous beneficial effects, ranging from anti-bacterial activities to increases in local blood flow, and that they can somehow protect tissues from damage when oxygen is suddenly cut off and then rapidly restored, as occurs during heart attacks and strokes. To study the molecular underpinnings of this protective effect of nitrite, the researchers at Boston University School of Medicine used a rat model in which they administered nitrite only once, causing a short spike in circulating levels, as a way to simulate the types of naturally occurring increases in nitrite that follow exercise or consumption of a meal rich in nitrate.

Good co-parenting may reduce children's problems

Warm, cooperative co-parenting between mothers and fathers may help protect children who are at risk for some types of behavior problems, a new study suggests. Researchers found that supportive co-parenting helped children who have difficulty regulating their behavior and attention levels – what researchers call effortful control. The study looked at changes in children’s level of aggressive behavior and other forms of “acting out” as they went from 4 years old to 5 years old. Results showed that children who had low levels of effortful control generally showed increases in these negative behaviors over the course of the year – unless their parents had a supportive co-parenting relationship.

Research trial appeal for pregnant smokers

Mums-to-be across the East Midlands are being invited to take part in research that aims to establish whether nicotine patches are safe and effective for pregnant smokers. Around 750 women have already signed up for the £1.3 million Smoking, Nicotine and Pregnancy (SNAP) trial but a further 300 participants are being sought by the researchers in The University of Nottingham’s Division of Primary Care. The call follows the recent launch of a powerful Government campaign to raise awareness of the dangers of women smoking in pregnancy and the extremely serious health risks it can pose to both the mother and her unborn child.
Around 30 per cent of pregnant women smoke and researchers say it can cause significant health problems for the unborn child. It accounts for around 4,000 fetal deaths every year, including miscarriages, and can contribute to premature births, low birth weight, cot death and asthma. It is also associated with problems later in childhood, including attention deficit and learning difficulties. Smoking brings the fetus into contact not just with nicotine but with a long list of other harmful chemicals. Expert consensus is that using nicotine replacement therapy (NRT), such as patches, is probably safer than smoking. However, while NRT can double a non-pregnant smoker’s chances of giving up, pregnant women metabolise nicotine a lot faster so it cannot be assumed that NRT will even work for them. The University of Nottingham trial will aim to establish empirically that they are safe and effective.

Increased understanding of immune system activation

Linda Andersson at Malmö University in Sweden has studied the ability of dendritic cells to sample the surrounding environment. To understand how different materials are taken up and what happens within the cells can for example facilitate the development of new vaccines. “The immune system is a large and important part of ourselves and the dendritic cells are important for the activation of this system”, Linda Andersson says. “One task of the immune system is to protect the body from infections. The dendritic cells have an unique ability to obtain samples from its environment and treat the material, in process called endocytosis. In my study I have explored how dendritic cells recognise and capture particles.” To study the endocytosing ability of dendritic cells Linda Andersson has used zeolite particles and through them different biomolecules are transported into the cell. With the help of zeolites you can follow different paths and study what happens within the cell. “The result shows that zeolites are an useful tool for studying endocytosis and that there are differences between various dendritic cells”, Linda Andersson says.

Old Cells Work Differently

The agglutination and accumulation of proteins in nerve cells are major hallmarks of age-related neurodegenerative illnesses such as Alzheimer's disease. Cellular survival thus depends on a controlled removal of excessive protein. Scientists at Johannes Gutenberg University Mainz have now discovered exactly how specific control proteins regulate protein breakdown during the ageing process. Every protein in our cells has a defined life span. At the end of this time and even sooner (e.g., in response to injury caused by external factors such as oxidative stress), proteins are eliminated by means of a specific protein degradation process. The quantity of proteins requiring elimination can rise in the face of ongoing oxidative stress, as can occur during the ageing process and in neurodegenerative illnesses. Damaged proteins that cannot be rendered harmless through the cell's "protein purification plant" tend to aggregate and accumulate, thereby threatening the survival of the cell. Nerve cells are especially susceptible to such protein accumulation, and the agglutination of proteins in nerve cells is a characteristic pathological symptom of a wide spectrum of age-associated neurodegenerative illnesses in humans, such as Alzheimer's disease and Parkinson's disease. Effective protein quality control is thus a requirement for the survival of all cells.

Cleansing toxic waste – with vinegar

Engineers and environmental scientists at the University of Leeds are developing methods of helping contaminated water to clean itself by adding simple organic chemicals such as vinegar. The harmful chromium compounds found in the groundwater at sites receiving waste from former textiles factories, smelters, and tanneries have been linked to cancer, and excessive exposure can lead to problems with the kidneys, liver, lungs and kin. The research team, led by Dr Doug Stewart from the School of Civil Engineering and Dr Ian Burke from the School of Earth and Environment, has discovered that adding dilute acetic acid (vinegar) to the affected site stimulates the growth of naturally-occurring bacteria by providing an attractive food source. In turn, these bacteria then cleanse the affected area by altering the chemical make-up of the chromium compounds to make them harmless. “The original industrial processes changed these chemicals to become soluble, which means they can easily leach into the groundwater and make it unsafe, says Dr Burke. “Our treatment method reconverts the oxidised chromate to a non-soluble state, which means it can be left safely in the ground without risk to the environment. As it is no longer ‘bio-available’ it doesn’t present any risk to the surrounding ecosystem.” Chromate chemicals have previously been successfully treated in situ in neutral Ph conditions, but this study is unique in that it concentrates on extremely alkaline conditions, which are potentially much more difficult to treat.

Nanosensors to prevent illnesses

Researchers at the Cidetec-IK4 technological centre have developed electrochemical sensors that, amongst other functions, enable the detection of possible mutations in DNA in a more rapid manner that has been achieved to date. The most notable aspect of the developed research is that this detection of DNA has been employed solely as a concept test, to study the viability of sensors. Thus, a wide range of possibilities has been opened for the coming years, in which nanosensors will be able to be applied to detect other types of molecules and even in the study of genetic illnesses. The scientific magazine NanoLetters, published by the American Chemical Society, has reflected the importance of this research, drawn up by a Cidetec-IK4 team in collaboration with the University of Berkeley and the CSIC in a project for the manufacture of nanosensors, both optical and electrochemical. The achievement of this research, and the reason the article was published in NanoLetters, lies in the fact that the el sensor developed employs only a nanotransistor the cable of which is a simple carbon nanotube. This has enabled the detection of non-modified DNA probes. The sensor detects DNA sequences and, thus, could be employed in genetics and in biotechnology. With certain genetic illnesses, the causal gene is known. Patients with a specific sequence of genes develop a specific disease. What the sensor can do is to detect these specific sequences of DNA given that, by its nature, it is highly selective.

Are vitamin supplements effective in celiac disease patients?

The study demonstrates in agreement with earlier findings, that both the presence and the severity of coeliac disease were determinants of homocysteine levels. The regular use of B vitamin supplements was associated with higher serum vitamin B6, folate, and vitamin B12 and lower plasma homocysteine levels in patients with coeliac disease. Furthermore, B vitamin supplements seem to have a protective role against the effect of villous atrophy on homocysteine levels, irrespective to the genetic susceptibility status as manifested by carrying the C677T polymorphism of 5,10-methylenetetrahydrofolate reductase.

Electroacupuncture protects acetylsalicylic acid-induced acute gastritis in rats

Nonsteroidal anti-inflammatory drugs (NSAIDs) are widely used as anti-inflammatory and analgesic agents. However, they often cause gastrointestinal injury in gastric lesions by inhibiting COX (cyclooxygenase) and detailed mechanism remains unclear. Thus, effective strategies are required to protect the gastrointestinal mucosa. A research article to be published on February 28, 2009 in the World Journal of Gastroenterology addresses this question. The research team led by Dr. Choi from Korea Institute of Oriental Medicine investigated the protective effects of acupuncture against NSAID-induced ulceration in a rat model. In their study, 72 rats were randomly divided into three groups including control (administered with distilled water), ASA group (administered 100 mg/kg ASA) and EA group (administered EA + 100 mg/kg ASA). Each rat was fasted for 18 to 24hours before experimentation, and lesion scores, gastric acidity, cyclooxygenase (COX)-1 and -2 mRNA levels, and total nitric oxide (NO) concentration were measured. They found that the lesion scores of the EA group were significantly lower than those of the NSAID-induced ulceration group. Gastric acidity of NSAID-induced ulceration group and EA group was reduced as compared to the control group. COX-1 and -2 mRNA levels were significantly increased in the EA group as compared to the control and NSAID-induced ulceration group, and NO levels were also significantly increased in the EA group as compared to the NSAID-induced ulceration group.

Influence of 'obesity gene' can be offset by healthy diet

Children who carry a gene strongly associated with obesity could offset its effect by eating a low energy density diet, according to new research from UCL (University College London) and the University of Bristol published today in PLoS ONE. The study, based on data from a sample of 2275 children from the Bristol-based ALSPAC study (Children of the 90s) provides evidence that people might be able to avoid becoming obese if they adopt a healthier diet with a low energy density – even those who carry the FTO gene, identified as being a high risk gene for obesity. Dietary energy density (DED) refers to the amount of energy consumed per unit weight of food, or number of calories per bite. A low dietary energy density can be achieved by eating lots of water-rich foods like fruits and vegetables and limiting foods high in fat and sugar like chocolate and biscuits. The researchers looked at how DED affected the build up of fat in the body over a period of three years in children aged between 10 and 13 years old. They found that children with a more energy dense diet (more calories per bite) tended to have more fat mass three years later and also confirmed that those carrying the high risk gene had greater fat mass overall. When the researchers looked at whether children with the FTO gene had a stronger reaction to an energy dense diet than children with a lower genetic risk they found that they did not. These results indicate that if a child with a high genetic risk eats a diet with fewer calories per bite, they may be able to offset the effect of the gene on weight gain and so stay a healthy weight.

Fast-food density and neighborhood walkability affect residents' weight and waist size

In a research article published recently by the American Journal of Epidemiology, Oregon Research Institute (ORI) scientist Fuzhong Li, Ph.D., and colleagues show that a high-density of fast food outlets was associated with an increase of 3 pounds in weight and .8 inches in waist circumference among neighborhood residents who frequently ate at those restaurants. In contrast, high-walkability neighborhoods were associated with a decrease of 2.7 pounds in weight and 0.6 inches in waist size among residents who increased their levels of vigorous physical activity during a one-year period. "This is one of the few longitudinal studies that focus on change in individuals' body weight over time in relation to their lifestyle behaviors and immediate living environments," noted Dr. Li. "The uniqueness of this study lies in its environment-person approach which we use to show that health-impeding environments, such as a high density of fast-food outlets, together with residents' behavior, such as eating fast food regularly, can have an unhealthy impact on body weight. On the other hand, health-promoting environments, such as walkable neighborhood streets, in conjunction with physically active residents, can have a positive impact on body weight over time." said Dr. Li.

How stress unravels the brain's structure

The helpless behavior that is commonly linked to depression and post-traumatic stress disorder (PTSD) is preceded by stress-related losses of synapses—microscopic connections between brain cells—in the brain's hippocampal region, researchers at Yale School of Medicine report in the March 1 issue of Biological Psychiatry. The team used a six-day treatment with the antidepressant desipramine to reverse helpless behavior and restore hippocampal synapses in rats. "In clinical practice, the main problem with antidepressants is that they require weeks to exert their effect," said lead scientist on the project Tibor Hajszan, M.D., associate research scientist in the Department of Obstetrics, Gynecology & Reproductive Sciences at Yale School of Medicine. "Because there are ways to restore these lost hippocampal synapses in as little as hours or even minutes, our laboratory is currently testing rapid-acting antidepressants that could provide immediate relief from depressive symptoms." Mental health disorders, including depression, are rapidly becoming the second largest public health problem, said Hajszan. "This is magnified by the fact that current antidepressant drugs remain ineffective in the majority of patients," he said.

One Drug May Help People Both Lay Down the Drink and Put Out the Cigarette

A popular smoking cessation drug dramatically reduced the amount a heavy drinker will consume, a new Yale School of Medicine study has found. Heavy-drinking smokers in a laboratory setting were much less likely to drink after taking the drug varenicline compared to those taking a placebo, according to a study published online in the journal Biological Psychiatry. The group taking varenicline, sold as a stop-smoking aid under the name Chantix, reported feeling fewer cravings for alcohol and less intoxicated when they did drink. They were also much more likely to remain abstinent after being offered drinks than those who received a placebo, the study found.

Stem cells could halt osteoporosis, promote bone growth

While interferon gamma sounds like an outer space weapon, it's actually a hormone produced by our own bodies, and it holds great promise to repair bones affected by osteoporosis. In a new study published in the journal Stem Cells, researchers from the Research Institute of the McGill University Health Centre explain that tweaking a certain group of multipotent stem cells (called mesenchymal stem cells) with interferon (IFN) gamma may promote bone growth. "We have identified a new pathway, centered on IFN gamma, that controls the bone remodelling process both in-vivo and in-vitro," explains Dr. Kremer, the study's lead author and co-director of the Musculoskeletal Axis of the McGill University Health Centre. "More studies are required to describe it more precisely, but we are hopeful that it could lead to a better understanding of the underlying causes of osteoporosis, as well as to innovative treatments."

Is one diet as good as another? U of I study says no and tells you why

Any diet will do? Not if you want to lose fat instead of muscle. Not if you want to lower your triglyceride levels so you'll be less likely to develop diabetes and heart disease. Not if you want to avoid cravings that tempt you to cheat on your diet. And not if you want to keep the weight off long-term. "Our latest study shows you have a better chance of achieving all these goals if you follow a diet that is moderately high in protein," said Donald Layman, a University of Illinois professor emeritus of nutrition. The research was published in the March Journal of Nutrition. Layman's new study followed the weight-loss efforts of 130 persons at two sites, the U of I and Penn State University, during 4 months of active weight loss and 8 months of maintenance. Two previous studies had looked at short-term weight loss; this one was designed to look at long-term effects, he said. Although both plans were equal in calories, half the group followed a moderate-protein diet (40% carbohydrates, 30% protein, 30% fat) while the other followed a diet based on USDA's food-guide pyramid (55% carbohydrates, 15% protein, 15% fat). "Persons in the first group ate twice the amount of protein as the second group," said Layman. And the difference in protein made all the difference in improved body composition and body lipids, he said.