Health Technology Research Synopsis 99th Issue Date 06 FEB 11
Compiled By Ralph Turchiano www.vit.bz
Editors Top Five:
1.Unexpected Find Opens Up New Front in Effort to Stop HIV
- Hot flushes are linked with a significant reduction in breast cancer risk
- Why folic acid may prevent a first heart attack, but not a second
- Restrictive Diet May Reduce ADHD Symptoms
- At work against microbes for over a century Nanosilver: a new name – well known effects
1. Unexpected Find Opens Up New Front in Effort to Stop HIV
2. Rising indoor winter temperatures linked to obesity?
- 3. Small bowel blood flow in healthy subjects receiving low-dose aspirin
- 4. Hot flushes are linked with a significant reduction in breast cancer risk
- 5. Eating poorly can make us depressed
- 6. Discovery of a biochemical basis for broccoli’s cancer-fighting ability
- 7. Vitamin D deficiency alters lung growth and decreases lung function
- 8. Exposure to worm infection in the womb may protect against eczema, study suggests
- 9. Researchers discover age of onset of puberty predicts adult osteoporosis risk
- 10. A deficiency of dietary omega-3 may explain depressive behaviors
- 11. New probiotic combats inflammatory bowel disease
- 12. More than allergies: Histamine may be a possible drug target for multiple sclerosis
- 13. At work against microbes for over a century Nanosilver: a new name – well known effects
- 14. Tonsillectomy linked to excess weight gain in kids
- 15. Specific populations of gut bacteria linked to fatty liver
- 16. Want more efficient muscles? Eat your spinach
- 17. Size of airborne flu virus impacts risk, Virginia Tech researchers say
- 18. Why folic acid may prevent a first heart attack, but not a second
- 19. Restrictive Diet May Reduce ADHD Symptoms
Unexpected Find Opens Up New Front in Effort to Stop HIV
HIV’s Trickery within the Macrophage Revealed
Baek Kim, Ph.D.HIV adapts in a surprising way to survive and thrive in its hiding spot within the human immune system, scientists have learned. While the finding helps explain why HIV remains such a formidable foe after three decades of research – more than 30 million people worldwide are infected with HIV – it also offers scientists a new, unexpected way to try to stop the virus.
The work by researchers at the University of Rochester Medical Center and Emory University was published Dec. 10 in the Journal of Biological Chemistry.
It’s thanks largely to its ability to hide out in the body that HIV is able to survive for decades and ultimately win out against the body’s relentless immune assault. One of the virus’s favorite hiding spots is an immune cell called a macrophage, whose job is to chew up and destroy foreign invaders and cellular debris.
For more than 15 years, Baek Kim, Ph.D., has been fascinated by HIV’s ability to take cover in a cell whose very job is to kill foreign cells. In the last couple of years Kim, professor of Microbiology and Immunology at the University of Rochester Medical Center, has teamed with Emory scientist Raymond F. Schinazi, Ph.D., D.Sc., director of the Laboratory of Biochemical Pharmacology at Emory’s Center for AIDS Research, to test whether the virus is somehow able to sidestep its usual way of replicating when it’s in the macrophage.
The pair found that when HIV faces a shortage of the molecular machinery needed to copy itself within the macrophage, the virus adapts by bypassing one of the molecules it usually uses and instead tapping another molecule that is available.
Normally, the virus uses dNTP (deoxynucleoside triphosphate, the building blocks for making the viral genetic machinery) to get the job done, but dNTP is hardly present in macrophages – macrophages don’t need it, since they don’t replicate. But macrophages do have high levels of a closely related molecule called rNTP (ribonucleoside triphosphate), which is more versatile and is used in cells in a variety of ways. The team found that HIV uses primarily rNTP instead of dNTP to replicate inside macrophages.
“The virus would normally just use dNTP, but it’s simply not available in great quantities in the macrophage. So HIV begins to use rNTP, which is quite similar from a chemical perspective. This is a surprise,” said Kim. “The virus just wants to finish replicating, and it will utilize any resource it can to do so.”
When the team blocked the ability of the virus to interact with rNTP, HIV’s ability to replicate in macrophages was slashed by more than 90 percent.
The work opens up a new front in the battle against HIV. Current drugs generally target dNTP, not rNTP, and take aim at the infection in immune cells known at CD4+ T cells. The new research opens up
the possibility of targeting the virus in macrophages – where the virus is out of reach of most of today’s drugs.
“The first cells that HIV infects in the genital tract are non-dividing target cell types such as macrophages and resting T cells” said Kim. “Current drugs were developed to be effective only when the infection has already moved beyond these cells. Perhaps we can use this information to help create a microbicide to stop the virus or limit its activity much earlier.”
Kim notes that a compound that targets rNTP already exists. Cordycepin in an experimental compound, derived from wild mushrooms, that is currently being tested as an anti-cancer drug. The team plans to test similar compounds for anti-HIV activity.
“This significant breakthrough was unappreciated prior to our paper. We are now exploiting new anti- HIV drugs jointly based on this novel approach that are essentially not toxic and that can be used to treat and prevent HIV infections,” said Schinazi, who has developed several of the drugs currently used to treat HIV patients.
The first authors of the paper, who contributed equally to the project, are graduate students Edward Kennedy of Rochester and Christina Gavegnano of Emory. Other authors include, from Rochester, graduate students Laura Nguyen and Amanda Lucas; undergraduate Rebecca Slater of the Department of Biomedical Engineering; and from Emory, post-doctoral associate Emilie Fromentin.
The work was funded by the National Institute of Allergy and Infectious Diseases and the U.S. Department of Veterans Affairs, where Schinazi is also employed
Public release date: 24-Jan-2011
Rising indoor winter temperatures linked to obesity?
Increases in winter indoor temperatures in the United Kingdom, United States and other developed countries may be contributing to rises in obesity in those populations, according to UCL research published today.
The review paper, published in the journal Obesity Reviews, examines evidence of a potential causal link between reduced exposure to seasonal cold and increases in obesity in the UK and US.
Reduced exposure to cold may have two effects on the ability to maintain a healthy weight: minimising the need for energy expenditure to stay warm and reducing the body’s capacity to produce heat. The review summarises the evidence for increases in winter indoor temperatures in the UK and US and also examines the biological plausibility of the idea that exposure to seasonal cold could help to regulate energy balance and body weight on a population level.
The paper brings together existing evidence showing that winter indoor temperatures have increased over the last few decades and that there has also been an increase in homogenisation of temperatures in domestic settings. Increasing expectations of thermal comfort mean that seasonal cold exposure is decreasing and we are spending more time exposed to milder temperatures.
The authors also discuss the role of brown adipose tissue (brown fat) in human heat production. Brown fat differs from white fat in that it has the capacity to burn energy to create heat, and its development in the body is thought to be triggered by exposure to cold temperatures. Recent studies suggest that increased time spent in warm conditions may lead to a loss of brown fat, and therefore reduced capacity to burn energy.
Lead author Dr Fiona Johnson, UCL Epidemiology & Public Health, said: “Increased time spent indoors, widespread access to central heating and air conditioning, and increased expectations of thermal comfort all contribute to restricting the range of temperatures we experience in daily life and reduce the time our bodies spend under mild thermal stress – meaning we’re burning less energy. This could have an impact on energy balance and ultimately have an impact on body weight and obesity.
“Research into the environmental drivers behind obesity, rather then the genetic ones, has tended to focus on diet and exercise – which are undoubtedly the major contributors. However, it is possible that other environmental factors, such as winter indoor temperatures, may also have a contributing role. This research therefore raises the possibility for new public health strategies to address the obesity epidemic.”
Co-author, Marcella Ucci , UCL Bartlett School of Graduate Studies, said: “The findings suggest that lower winter temperatures in buildings might contribute to tackling obesity as well reducing carbon emissions.”
Public release date: 25-Jan-2011
Small bowel blood flow in healthy subjects receiving low-dose aspirin
Low-dose acetylsalicylic acid (ASA) has been widely used for prevention of cardiovascular and cerebrovascular events. Severalstudieshaveshownthatmucosalbreaks caused by taking low-dose ASAoccurrednotonlyin the upper gastrointestinal tract but also in the lower gastrointestinal tract. However the cause of small bowel injury is not clear. One of the mechanisms of drug-induced small bowel damage is decrease in blood flow.
A research article to be published on January 14, 2011 in the World Journal of Gastroenterology addresses this question. The authors investigated the relationship between low-dose ASA-induced small bowel mucosal damage and small bowel blood flow, and also evaluated the preventive effect of rebamipide against small bowel damage and the effect of rebamipide on blood flow.
The results indicated that low-dose ASA-induced decrease in small bowel blood flow is correlated with small-bowel mucosal injury. Rebamipide does not decrease small bowel blood flow.
This study may represent a future strategy for therapeutic intervention in the treatment of patients with low-dose aspirin-induced small bowel mucosal damage.
Public release date: 25-Jan-2011
Hot flushes are linked with a significant reduction in breast cancer risk
The more frequent and severe the hot flushes, the lower the cancer risk
SEATTLE – Women who have experienced hot flushes and other symptoms of menopause may have a 50 percent lower risk of developing the most common forms of breast cancer than postmenopausal women who have never had such symptoms, according to a recent study by researchers at Fred Hutchinson Cancer Research Center.
The results of the first study to examine the relationship between menopausal symptoms and breast cancer risk are available online ahead of the February print issue of Cancer Epidemiology Biomarkers and Prevention.
The protective effect appeared to increase along with the number and severity of menopausal symptoms,
according to senior author Christopher I. Li, M.D., Ph.D., a breast cancer epidemiologist in the Hutchinson Center’s Public Health Sciences Division.
“In particular we found that women who experienced more intense hot flushes – the kind that woke them up at night – had a particularly low risk of breast cancer,” he said.
Li and colleagues suspected a link between menopause misery and decreased breast cancer risk because hormones such as estrogen and progesterone play an important role in the development of most breast cancers, and reductions in these hormones caused by gradual cessation of ovarian function can impact the frequency and severity of menopausal symptoms.
“Since menopausal symptoms occur as hormone levels fluctuate and drop, we hypothesized that women who experienced symptoms such as hot flushes and night sweats – particularly frequent and severe symptoms – might have a lower risk of breast cancer due to decreased estrogen levels,” he said.
Indeed, the researchers found a 40 percent to 60 percent reduction in the risk of invasive ductal and invasive lobular carcinoma – the two most common types of breast cancer – among women who experienced hot flushes and other symptoms. The association between such symptoms and decreased cancer risk did not change even after the researchers accounted for other factors known to boost breast cancer risk, such as obesity and use of hormone replacement therapy.
For the study, which was funded by the National Cancer Institute, Li and colleagues interviewed 1,437 postmenopausal Seattle-area women, 988 of whom had been previously diagnosed with breast cancer and 449 of whom had not, who served as a comparison group. The women were surveyed about perimenopausal and menopausal symptoms ranging from hot flushes, night sweats and insomnia to vaginal dryness, irregular or heavy menstrual bleeding, depression and anxiety.
“While menopausal symptoms can certainly have a negative impact on quality of life, our study suggests that there may be a silver lining if the reduction in breast cancer risk is confirmed in future studies,” Li said. “If these findings are confirmed, they have the potential to improve our understanding of the causes of breast cancer and improve approaches to preventing this disease.”
Public release date: 26-Jan-2011
Eating poorly can make us depressed
Researchers from the universities of Navarra and Las Palmas de Gran Canaria have demonstrated that the ingestion of trans-fats and saturated fats increase the risk of suffering depression, and that olive oil, on the other hand, protects against this mental illness.
They have confirmed this after studying 12,059 SUN Project volunteers over the course of six years; the volunteers had their diet, lifestyle and ailments analyzed at the beginning of the project, over its course and at the end of the project. In this way the researchers confirmed that despite the fact that at the beginning of the study none of the volunteers suffered from depression, at the end of the study 657 new cases had been detected.
Of all these cases, the participants with an elevated consumption of trans-fats (fats present in artificial form in industrially-produced pastries and fast food, and naturally present in certain whole milk products) “presented up to a 48% increase in the risk of depression when they were compared to participants who did not consume these fats,” affirmed Almudena Sánchez-Villegas, Associate Professor of Preventive Medicine at the University of Las Palmas de Gran Canaria, first author of the article.
In addition, the study demonstrated a dose-response relationship, “whereby the more trans-fats were consumed, the greater the harmful effect they produced in the volunteers,” the expert stated.
Furthermore, the team, directed by Miguel Ángel Martínez-González, Professor of Preventive Medicine at the University of Navarra, also analyzed the influence of polyunsaturated fats (abundant in fish and vegetable oils) and of olive oil on the occurrence of depression. “In fact, we discovered that this type of healthier fats, together with olive oil, are associated with a lower risk of suffering depression,” emphasized the researcher and director of the SUN Project.
150 million persons depressed worldwide
Thus, the results of the study corroborate the hypothesis of a greater incidence of the disease in countries of the north of Europe compared to the countries of the south, where a Mediterranean dietary pattern prevails. Nevertheless, experts have noted that the incidence of the disease has increased in recent years, so that today some 150 million persons are affected worldwide, where it is the principal cause of loss of years of life in those countries with a medium-to-high per capita income.
This due, according to Almudena Sánchez Villegas, “to radical changes in the sources of fats consumed in Western diets, where we have substituted certain types of beneficial fats—polyunsaturated and monounsaturated in nuts, vegetable oils and fish—for the saturated and trans-fats found in meats, butter and other products such as mass-produced pastries and fast food”.
In addition, the research—published in the online peer reviewed journal PLoS ONE—has been performed on a population with a low average intake of trans-fats, given that it made up only 0.4% of the total energy ingested by the volunteers. “Despite this, we observed an increase in the risk of suffering depression of nearly 50%. On this basis,” concluded Miguel A. Martínez, “we derive the importance of taking this effect into account in countries like the U.S., where the percentage of energy derived from these foots is around 2.5%”.
Finally, the analysis, headed by the University of Navarra and the University of Las Palmas de Gran Canaria, suggests that both depression as well as cardiovascular disease are influenced in a similar manner by diet, and might share similar mechanisms in their origin. This hypothesis is further suggested by numerous studies that indicate the harmful effect of trans-fats and saturated fats on the risk of cardiovascular disease.
Public release date: 26-Jan-2011
Discovery of a biochemical basis for broccoli’s cancer-fighting ability
Scientists are reporting discovery of a potential biochemical basis for the apparent cancer-fighting ability of broccoli and its veggie cousins. They found for the first time that certain substances in the vegetables appear to target and block a defective gene associated with cancer. Their report, which could lead to new strategies for preventing and treating cancer, appears in ACS’ Journal of Medicinal Chemistry.
Fung-Lung Chung and colleagues showed in previous experiments that substances called isothiocyanates (or ITCs) — found in broccoli, cauliflower, watercress, and other cruciferous vegetables — appear to stop the growth of cancer. But nobody knew exactly how these substances work, a key to developing improved strategies for fighting cancer in humans. The tumor suppressor gene p53 appears to play a key role in keeping cells healthy and preventing them from starting the abnormal growth that is a hallmark of cancer. When mutated, p53 does not offer that protection, and those mutations occur in half of all human cancers. ITCs might work by targeting this gene, the report suggests.
The scientists studied the effects of certain naturally-occurring ITCs on a variety of cancer cells, including lung, breast and colon cancer, with and without the defective tumor suppressor gene. They found that ITCs are capable of removing the defective p53 protein but apparently leave the normal one alone. Drugs based on natural or custom-engineered ITCs could improve the effectiveness of current cancer treatments or lead to new strategies for treating and preventing cancer
Public release date: 28-Jan-2011
Vitamin D deficiency alters lung growth and decreases lung function
Previously linked to the severity of asthma and chronic obstructive pulmonary disease (COPD) in humans, vitamin D deficiency has now been shown to alter lung structure and function in young mice. The new study, conducted by researchers in Australia, offers the first concrete evidence linking vitamin D deficiency with deficits in lung function and altered lung structure.
The findings were published online ahead of the print edition of the American Thoracic Society’s American Journal of Respiratory and Critical Care Medicine.
“The results of this study clearly demonstrate that vitamin D deficiency alters lung growth, resulting in lower lung volume and decrements in lung function,” said Graeme Zosky, PhD, a research fellow at the Telethon Institute for Child Health Research in Subiaco, Australia. “This is the first direct mechanistic evidence showing that vitamin D deficiency alters lung development, which may explain the association between obstructive lung disease and levels of vitamin D.”
To conduct their study, the researchers used a mouse model of vitamin D deficiency and evaluated lung responses of two-week-old mice, comparing them to control mice without vitamin D deficiency to determine what, if any, effects the deficiency may have caused in the growth, structure or function of the lungs.
Lung volume and lung function were evaluated using a plethysmograph, an instrument used to measure the amount of air in the lung, and via forced oscillation, a technique used to measure the resistance to air flow in the lungs. Microscopic lung tissue samples were also evaluated to assess changes in lung structure.
“The aim of this study was to determine if vitamin D deficiency results in altered lung function and/or structure as a potential explanation for the association between vitamin D and chronic respiratory disease,” said Dr. Zosky, who is also an adjunct senior lecturer at the University of Western Australia’s Centre for Child Health Research. “Specifically, we aimed to determine if vitamin D deficiency has an influence on lung growth as indicated by a decrease in lung volume. We also wanted to determine if the deficiency alters the mechanical properties of the lung tissue due to changes in the structure of the lung.”
The researchers found that airway resistance was significantly higher while lung volume was significantly lower in vitamin D-deficient mice compared to control mice. Examinations of specific tissue responses revealed model mice had reduced lung function. Lungs were also smaller in model mice, which Dr. Zosky said could have been caused by the deficiencies of the mother or of the offspring.
“Due to the nature of this study, we were not able to determine whether the differences in lung size and function we observed in the deficient offspring were the result of their own deficient status or as a consequence of developmental deficits that occurred in utero due to the mother’s deficiency,” he said.
Dr. Zosky noted that although recent studies suggest that vitamin D deficiency is associated with reduced lung function, causal data confirming a relationship between vitamin D and lung function have been lacking.
“For the first time, we have demonstrated a direct role for vitamin D in causing decreased lung function in the absence of known confounders such as physical inactivity, confirming the assertion by epidemiological studies that there is a relationship between vitamin D deficiency and lung function,” Dr. Zosky said. “The differences we observed in lung volume and lung mechanics, which were substantial and physiologically relevant, raise serious concerns regarding the increased prevalence of vitamin D deficiency in communities around the world. The results also raise concerns about the potential this deficiency may have on lung health, and in particular, the potential impact deficiency may have on the susceptibility to obstructive lung disease.”
Dr. Zosky said the study results have important implications for prevention of lung diseases in populations where vitamin D deficiencies are common. Future studies need to be conducted to determine whether vitamin D deficiency-induced alterations in lung growth increase the severity of obstructive lung disease and to identify susceptible populations whose use of dietary vitamin D supplementation could be used to improve lung health outcomes, he added.
Public release date: 28-Jan-2011
Exposure to worm infection in the womb may protect against eczema, study suggests
Exposure to worm infections in the womb may protect a newborn infant from developing eczema, a study funded by the Wellcome Trust suggests. A large trial in Uganda showed that treating a pregnant woman for worm infections increased her child’s chances of developing the allergic skin disease.
Published this week in the journal Pediatric Allergy and Immunology, the research supports the so-called ‘hygiene hypothesis’, which proposes that exposure to infections in early childhood can modify the immune system and protect the child from allergies later in life.
The World Health Organisation estimates that one in five of the world’s population suffers from allergic diseases such as asthma and eczema, but this epidemic is no longer restricted to developed countries: more than four out of five deaths due to asthma occur in low and lower-middle income countries. The declining incidence and prevalence of infectious diseases – including chronic infection by worms known as helminths – is widely considered to be an important contributor contributing to this increase.
Helminth infection can cause symptoms ranging from mild anaemia through to stomach pain and vomiting, depending on how intense the infection is, but very often people have no symptoms at all. The parasitic worms tend to enter the body through contaminated food or water, mosquito bites or through walking in bare feet on contaminated soil.
A preliminary study carried out at the MRC/UVRI Uganda Research Unit on AIDS in Entebbe, Uganda in 2005 showed a reduced risk of eczema among infants whose mothers had worms and suggested an increased incidence among infants of mothers who received albendazole – a commonly used drug to treat worm infection – during pregnancy compared to infants whose mothers received a placebo.
In a follow-up study, researchers carried out a randomised, double-blind trial on 2,507 pregnant women in Uganda, comparing those treated with either albendazole or a second drug, praziquantel, against those administered a placebo, and looking at how this affected their offspring’s risk of developing eczema.
Harriet Mpairwe, first author of the new study, says: “Worm infections can adversely affect a person’s health, but the evidence also suggests that exposure to infection early in a child’s life can have a beneficial effect in terms of modifying its immune system and protecting against allergies. We wanted to examine in a large cohort what effect de-worming women during pregnancy has on their
The researchers showed for the first time that treatment of pregnant women with albendazole appeared to almost double the risk of eczema in their offspring (an increase by a factor of 1.8) and that treatment with praziquantel more than doubled (an increase by a factor of 2.6) the risk of eczema among infants of mothers infected by the Schistosoma mansoni worm (a parasite which causes the disease schistosomiasis).
The findings support the hypothesis that maternal worms during pregnancy, neonatal life and early breastfeeding, may protect against allergy in infancy and that treatment of these worms during pregnancy increases the risk of allergy.
Professor Alison Elliott from the London School of Hygiene and Tropical Medicine, senior author of the study, says: “Our study suggests that routine de-worming during pregnancy, in settings where most worm infections are mild, may not be beneficial for the children and may actually cause problems with allergy. However, before we recommend changes to treatment policy, we need to do more work to confirm these findings and better understand what is happening.
“The findings certainly support the so-called ‘hygiene hypothesis’. What will be important for the eczema story will be to see whether there are long term effects on allergy, especially asthma, at school age. Our next step is to investigate this further.”
Researchers discover age of onset of puberty predicts adult osteoporosis risk
Later puberty results in lower bone mass and increases risk of fracture
LOS ANGELES (January 27, 2011) – A team of researchers led by Vicente Gilsanz, MD, PhD, director of Clinical Imaging at The Saban Research Institute of Children’s Hospital Los Angeles, determined that the onset of puberty was the primary influence on adult bone mineral density, or bone strength. Length of puberty did not affect bone density.
Reduced bone mineral density leads to osteoporosis, resulting in bones becoming increasingly brittle and at risk for fracture. Osteoporosis is a significant public health issue with the cost of treatment in 2010 estimated at $10 billion. This condition affects 55% of Americans aged 50 and older.
The Bone Mineral Density in Childhood Study is an ongoing multicenter study examining bone development in healthy children and teenagers of both sexes and ethnic groups in the United States. For this analysis, the investigators studied 78 girls and 84 boys who had just entered puberty, until they reached sexual maturity.
“Puberty has a significant role in bone development,” explained Dr. Gilsanz. “During this time, bones lengthen and increase in density. At the end of puberty the epiphyseal plates close, terminating the ability of the bones to lengthen. When this occurs, the teenager has reached their maximum adult height and peak bone mass. We found that early puberty was associated with greater bone mass while later puberty resulted in less.”
Adolescents with short stature sometimes undergo medical intervention to delay puberty in an effort to achieve greater height. This study indicates that prolonging the growth period by delaying puberty may have unexpected consequences in later life.
The 2000 National Institutes of Health Consensus Development Conference on Osteoporosis Prevention, Diagnosis, and Therapy identified bone mineral deposition during adolescence as a critical determinant of osteoporosis risk later in life. The care of patients with osteoporosis is difficult, and most therapies increase bone density by small amounts yet requires long periods of treatment. In contrast, during puberty large increases in bone density occur over a short period of time.
Given that the rate of decline of bone mass in adulthood is approximately 1% to 2% each year, a 10% to 20% increase in bone density resulting from a natural early puberty corresponds to an additional 10 to 20 years of protection against the normal age-related decline in bone strength.
A deficiency of dietary omega-3 may explain depressive behaviors
Neuroscience of nutrition
How maternal essential fatty acid deficiency impact on its progeny is poorly understood. Dietary insufficiency in omega-3 fatty acid has been implicated in many disorders. Researchers from Inserm and INRA and their collaborators in Spain collaboration, have studied mice fed on a diet low in omega-3 fatty acid. They discovered that reduced levels of omega-3 had deleterious consequences on synaptic functions and emotional behaviours. Details of this work are available in the online version of the journal Nature neuroscience, which can be accessed at: http://dx.doi.org/10.1038/nn.2736
In industrialized nations, diets have been impoverished in essential fatty acids since the beginning of the 20th century. The dietary ratio between omega-6 polyunsaturated fatty acid and omega-3 polyunsaturated fatty acid omega-3 increased continuously over the course of the 20th century. These fatty acids are “essential” lipids because the body cannot synthesize them from new. They must therefore be provided through food and their dietary balance is essential to maintain optimal brain functions.
Olivier Manzoni (Head of Research Inserm Unit 862, “Neurocentre Magendie”, in Bordeaux and Unit 901 “Institut de Neurobiologie de la Méditerranée” in Marseille), and Sophie Layé (Head of Research at INRA Unit 1286, “Nutrition et Neurobiologie Intégrative” in Bordeaux) and their co-workers hypothesized that chronic malnutrition during intra-uterine development, may later influence synaptic activity involved in emotional behaviour (e.g. depression, anxiety) in adulthood.
To verify their hypotheses, the researchers studied mice fed a life-long diet imbalanced in omega-3 and omega-6 fatty acids. They found that omega-3 deficiency disturbed neuronal communication specifically. The researchers observed that only the cannabinoid receptors, which play a strategic role in neurotransmission, suffer a complete loss of function. This neuronal dysfunction was accompanied by depressive behaviours among the malnourished mice.
Among omega-3 deficient mice, the usual effects produced by cannabinoid receptor activation, on both the synaptic and behavioural levels, no longer appear. Thus, the CB1R receptors lose their synaptic activity and the antioxidant effect of the cannabinoids disappears.
Consequently, the researchers discovered that among mice subjected to an omega-3 deficient dietary regime, synaptic plasticity, which is dependent on the CB1R cannabinoid receptors, is disturbed in at least two structures involved with reward, motivation and emotional regulation: the prefrontal cortex and the nucleus accumbens. These parts of the brain contain a large number of CB1R cannabinoid receptors and have important functional connections with each other.
“Our results can now corroborate clinical and epidemiological studies which have revealed associations
between an omega-3/omega-6 imbalance and mood disorders”, explain Olivier Manzoni and Sophie Layé. “To determine if the omega-3 deficiency is responsible for these neuropsychiatric disorders additional studies are, of course, required”.
In conclusion, the authors estimate that their results provide the first biological components of an explanation for the observed correlation between omega-3 poor diets, which are very widespread in the industrialized world, and mood disorders such as depression
Public release date: 31-Jan-2011
New probiotic combats inflammatory bowel disease
Probiotic offers possibility of safe, drug-free treatment
CHICAGO — You know the probiotics in your peach yogurt are healthful, but now it appears they may also be a powerful treatment for disease.
A genetically tweaked version of a common probiotic found in yogurt and cheese appears to be an effective therapy for inflammatory bowel diseases such as Crohn’s disease and ulcerative colitis. It may also prove to be useful in colon cancer, another disease triggered by inflammation.
Northwestern Medicine researchers deleted a gene in the probiotic Lactobacillus acidophilus and fed the new form to mice with two different models of colitis. After 13 days of treatment, the novel probiotic strain nearly eliminated colon inflammation in the mice and halted progression of their disease by 95 percent.
“This opens brand new avenues to treat various autoimmune diseases of the gut, including inflammatory bowel disease and colon cancer, all which can be triggered by imbalanced inflammatory immune responses,” said Mansour Mohamadzadeh, associate professor of medicine at Northwestern University Feinberg School of Medicine and lead investigator of the study. He also is a member of the Robert H. Lurie Comprehensive Cancer Center of Northwestern University.
The study will be published Jan. 31 in the Proceedings of the National Academy of Sciences.
While the origin of these bowel diseases is not known, Crohn’s disease and ulcerative colitis are two chronically relapsing diseases in which sufferers have an ongoing tissue inflammation that alters the functioning of the intestine. The diseases affect more than 1 million people in the United States and can cause weight loss, diarrhea, abdominal pain and cramping and gastrointestinal bleeding. Current drug treatment is not completely effective and patients can relapse, Mohamadzadeh said.
“Such gene targeting in a probiotic bacteria such as Lactobacillus acidophilus offers the possibility of a safe, drug-free treatment in the near future,” he said.
In the study, the modified Lactobacillus acidophilus entered the gut, which is akin to a battlefield of friendly fire with immune cells attacking the intestine. The Lactobacillus acidophilus acted as the gut’s peacekeeping force, calming the overstimulated immune cells.
The probiotic restored intestinal peace by mobilizing messenger immune cells, called dendritic cells. The dendritic cells, in turn, enhanced the production of other functional immune cells, regulatory T-cells that rebalanced intestinal and systemic inflammation.
“They essentially calm everything down and restore it to normal,” Mohamadzadeh explained. The next step will be a clinical trial with the new form of Lactobacillus acidophilus.
Mohamadzadeh and his colleagues at the Lurie Cancer Center are currently researching the effect of the new Lactobacillus acidophilus on colon cancer.
Public release date: 31-Jan-2011
Childhood obesity linked to health habits, not heredity: U-M study
University of Michigan Cardiovascular Center study shows obese children eat more school meals, watch more TV, exercise less than normal weight peers
ANN ARBOR, Mich. – Are some children genetically tuned to be overweight, or is lifestyle to blame for childhood obesity?
Check-ups of 1,003 Michigan 6th graders in a school-based health program showed children who are obese were more likely to consume school lunch instead of a packed lunch from home and spend two hours a day watching TV or playing a video game.
The results were compiled by the University of Michigan Cardiovascular Center and suggests unhealthy habits are feeding the childhood obesity trend.
“For the extremely overweight child, genetic screening may be a consideration,” says study senior author Kim A. Eagle, M.D., a cardiologist and a director of the U-M Cardiovascular Center. “For the rest, increasing physical activity, reducing recreational screen time and improving the nutritional value of school lunches offers great promise to begin a reversal of current childhood obesity trends.”
President Obama recently signed the Healthy, Hunger-Free Kids Act of 2010 to create healthier school menus for the 31 million children in the United States who eat lunch through school programs.
The act is designed to improve nutrition by reducing salt, fat and sugar in school meals and reduce childhood obesity which has tripled in the U.S. in the past 30 years.
The prevalence of obesity among U.S. children ages 6 to 11 has increased from 6.5 percent in 1980 to
19.6 percent in 2008.
Children involved in the study participate in Project Healthy Schools, school-based program supported by communities and the U-M Health System to teach middle school students about healthy lifestyles, in hopes of reducing their future risk of cardiovascular disease and diabetes.
Project Healthy Schools is available at 13 Michigan middle schools and is one of the few school-based programs to show sustained benefits in reducing cholesterol and high blood pressure among participants.
The U-M study was published in the American Heart Journal.
U-M researchers found that 58 percent of obese children had watched two hours of TV in the previous day, compared to 41 percent of non-obese children. Forty-five percent of obese students always ate school lunch, but only 34 percent of non-obese students ate school lunch.
Significantly fewer obese kids exercised regularly, took physical education classes, or were a member of a sports team.
Because the eating and exercise patterns of obese children were so different than their normal weight
peers, researchers concluded that lifestyle was more closely linked with childhood obesity, than genetics.
New evidence has emerged showing a leptin deficiency, a genetic mutation in the hormone that controls hunger, may cause a person to overeat.
“If diets and physical activity were similar in obese and non-obese students this would argue for a stronger genetic basis for obesity in children,” says study first author Taylor Eagle.
In the U-M study, 15 percent of the middle school students were obese, but nearly all, whether overweight or not, reported unhealthy habits.
More than 30 percent had consumed regular soda the previous day, and less than half remembered eating two portions of fruits and vegetables within the past 24 hours. Only one-third of students said they exercised for 30 minutes for five days in the previous week.
“It’s clear that opportunities to improve health abound for the majority of our students, not just the 15 percent who are already obese,” says study co-author Elizabeth Jackson, M.D., assistant professor of internal medicine at the U-M Cardiovascular Center.
Public release date: 31-Jan-2011
More than allergies: Histamine may be a possible drug target for multiple sclerosis
New research published in the Journal of Leukocyte Biology suggests that histamine plays an important role as an immune modulator, which could be a significant finding for multiple sclerosis research
If you think histamines are your nemesis during allergy season, here’s something that might change your perspective. New research published in the Journal of Leukocyte Biology (http://www.jleukbio.org) shows that histamine could be an important molecule to developing new treatments for multiple sclerosis (MS). In the study, the scientists analyzed the role of histamine in an animal model of multiple sclerosis and found that histamine plays a critical role in preventing MS or lessening its effects.
“We hope that our study will help design new therapies for autoimmune diseases and in particular MS, for which there is still not a definitive cure,” said Rosetta Pedotti, MD, Ph.D., a researcher involved in the work from the Neuroimmunology and Neuromuscular Disorders Unit at the Neurological Institute Foundation Carlo Besta in Milan, Italy.
Histamine is a neurotransmitter involved in allergic reactions and other physiological and pathological processes. It is best known for the role it plays in hypersensitivity reactions like allergies, and it generally works by dilating blood vessels and making vessel walls permeable so immune cells can move more easily. Scientists studied the direct effects of histamine and two similar molecules that bind specifically on histamine receptors 1 or 2. Using a mouse model of MS, researchers generated MS-causing T lymphocytes and then treated these cells with histamine or the two other molecules. The effects of these treatments were evaluated by T cell functions analysis including proliferation, cytokine production, intracellular signaling pathways activation, and adhesion to brain vessels. Results showed that histamine reduces the proliferation of myelin autoreactive T lymphocytes and the production of interferon-gamma, a crucial cytokine involved in brain inflammation and demyelination. Additionally, histamine reduced the ability of myelin autoreactive T cells to adhere to inflamed brain vessels, a crucial step in the development of MS.
“This research is very exciting for several reasons. First, it points to unexpected connection between pathways involved in autoimmunity and allergy and suggests previously unrecognized connections between these very different types of immune responses. Second, while extending studies in animal
models such as these to humans takes substantially more work, these new data point to a potentially novel drug target for MS and possibly other autoimmune or central nervous system diseases,” said John Wherry, Ph.D., Deputy Editor of the Journal of Leukocyte Biology.
Public release date: 27-Jan-2011
At work against microbes for over a century Nanosilver: a new name – well known effects
Nanosilver is not a new discovery by nanotechnologists – it has been used in various products for over a hundred years, as is shown by a new Empa study. The antimicrobial effects of minute silver particles, which were then known as “colloidal silver”, were known from the earliest days of its use.
As early as the 19th century minute silver particles were used, for example in antibacterial water filters. Numerous nanomaterials are currently at the focus of public attention. In particular silver nanoparticles are being investigated in detail, both by scientists as well as by the regulatory authorities. The assumption behind this interest is that they are dealing with a completely new substance. However, Empa researchers Bernd Nowack and Harald Krug, together with Murray Heights of the company HeiQ have shown in a paper recently published in the journal «Environmental Science & Technology» that nanosilver is by no means the discovery of the 21st century. Silver particles with diameters of seven to nine nm were mentioned as early as 1889. They were used in medications or as biocides to prevent the growth of bacteria on surfaces, for example in antibacterial water filters or in algaecides for swimming pools.
The material has always been the same
Thenanoparticleswere known as “colloidal silver” in those days, but what was meant was the same thenas now – extremely small particles of silver. The only new aspect is the use today of the prefix “nano”.“However,” according to Bernd Nowack, “nano does not mean something new, and nor does it mean something that is harmful.” When “colloidal silver” became available on the market in large quantities in the 1920s it was the topic of numerous studies and subject to appropriate regulation by the authorities. Even in those days the significance of the discovery of nanoparticles and how they worked was realized. “That is not to say that the possible side-effects of nanoparticles on humans and the environment should be played down or ignored,” adds Nowack. It is important to characterize in exact detail the material properties of nanosilver and not just to believe unquestioningly the doubts and reservations surrounding the product.
Nanosilver has different effects than silver
The term nanoparticle is understood to refer to particles whose dimensions are less than 100 nm. Because of their minute size nanoparticles have different properties than those of larger particles of the same material. For example, for a given volume nanoparticles have a much greater surface area, so they are frequently much more reactive than the bulk material. In addition, even in small quantities nanosilver produces more silver ions than solid silver. These silver ions are toxic to bacteria. Whether or not nanosilver represents a risk to humans and the environment is currently the subject of a great deal of
120 Years of Nanosilver History: Implications for Policy Makers, Bernd Nowack, Harald F. Krug, Murray Height, Environ Sci Technol, 2011, DOI: 10.1021/es103316q
Nanosilver in wastewater treatment plants
Currently there are hundreds of products in circulation which contain silver nanoparticles. Examples include cosmetics, food packaging materials, disinfectants, cleaning agents and – not least – antibacterial socks and underwear. Every year some 320 tonnes of nanosilver are used worldwide, some of which is released into wastewater, thus finding its way into natural water recirculation systems. What effects solar particles have on rivers, soil and the organisms that live in them has not yet been clarified in detail. A commentary by Bernd Nowack in the scientific journal “Science” discusses the implications of the newest studies on nanosilver in sewage treatment plants. More than 90% remains bound in the sewage sludge in the form of silver sulfide, a substance which is extremely insoluble and orders of magnitude less poisonous than free silver ions. It apparently does not matter what the original form of the silver in the wastewater was, whether as metallic nanoparticles, as silver ions in solution or as precipitated insoluble silver salts. “As far as the environmental effects are concerned, it seems that nanosilver in consumer goods is no different than other forms of silver and represents only a minor problem for eco-systems,” says Nowack.
What is still to be clarified, however, is in what form the unbound silver is present in the treated water released from sewage works, and what happens to the silver sulfide in natural waters. Is this stable and unreactive or is it transformed into other forms of silver?
Nanosilver Revisited Downstream, Bernd Nowack, Science, 2010, Vol. 330 no. 6007, pp. 1054-1055, DOI: 10.1126/science.1198074
Public release date: 31-Jan-2011
Tonsillectomy linked to excess weight gain in kids
Alexandria, VA — Tonsillectomy is the most common major surgical procedure performed in children. Children who undergo the surgical removal of their tonsils (tonsillectomy), with or without the removal of their adenoids (adenoidectomy), are at increased risk for becoming overweight after surgery, according to new research published in the February 2011 issue of Otolaryngology – Head and Neck Surgery.
Pediatric obesity has increased overwhelmingly over the last 20 years, with recent data suggesting that as many as 33 percent of American children are overweight and 17 percent obese. Obese children are at increased risk of becoming obese adults, thus making them susceptible to cardiovascular disease and diabetes.
The study sample included 795 children aged 0 to 18 years old, described as normal weight or overweight and who had tonsillectomy or adenotonsillectomy surgery. In 47.7 percent of patients, the primary reason for surgery was sleep-disordered breathing. The first group included three studies involving 127 children, whose body mass index (BMI) increased by 5.5-8.2%. The second group included three studies involving 419 patients, in whom the standardized weight scores increased in 46-100% patients. The third group included three studies with 249 patients, in whom 50 – 75% of the patients gained weight after
adenoidectomy. Each study was designed with different definitions of overweight and a range of follow-up periods
“There may have been a variety of proposed mechanisms for the weight gain following adenoidectomy,” writes author Anita Jeyakumar, MD. “Children with chronic tonsillitis may have dysphagia or odynophagia that may lead to a reduced calorie intake. When the diseased tonsils are removed, the child then is able to consume additional calories. Parents may also feel impelled to over-feed their child when recovering from chronic illness or surgery, further adding to caloric intake and weight gain.”
Based on these findings, the authors recommend that dietary and lifestyle advice be given to parents whose children are undergoing tonsillectomy. Growth monitoring after surgery is key to ensure that catch- up growth occurs within healthy limits.
Public release date: 31-Jan-2011
Specific populations of gut bacteria linked to fatty liver
Findings point to digestive bacterial influence on choline metabolism
The more we learn about biology, the closer we get to being able to treat disease – and the more complicated our understanding of disease itself becomes.
A new research finding showing a strong relationship between complex microbial ecologies in human intestines and the common but serious medical condition known as fatty liver illustrates this paradox.
From past genomic studies, we have learned that a mind-boggling multitude of different kinds of benign bacteria inhabit our intestines and that these populations can vary almost infinitely from one human being to the next. We know that the kind of food we eat is important to our health and we know that having the right bacteria in our intestines is important in digesting our food properly, but we still do not know how our individual variations in gut bacteria might influence more specific health issues. In particular, we do not know how these bacteria influence how the substances we eat affect our organ systems.
In the condition known as fatty liver, fat deposits build up in the liver, with potentially serious health consequences for nearly a third of the American population. Fatty liver can be caused by alcohol abuse, obesity, hormonal changes and/or diabetes. Recent work has suggested that diet is also important with strong indications that deficiencies in the essential nutrient choline might be partially involved in some incidences of the condition. Choline deficiency also implicates genetics, since many people lack the genes to efficiently make choline internally.
Now, a new bioinformatics finding shows that the abundance or scarcity of certain types of bacteria in the gut may also help predict susceptibility to non-alcoholic fatty liver. The implication of the finding is that these groups of bacteria may be influencing the body’s ability to properly use the choline available in food, though the study does not examine the specific metabolic activity of the bacteria involved.
In a metagenomic analysis of the microbial communities living in the intestinal tracts of 15 female patients participating in a study of the effects on liver condition from a choline-depleted diet, bioinformatics researchers at the University of North Carolina at Charlotte found a strong correlation between the relative abundances of two specific classes of bacteria and the development of fatty liver. A report on the finding appears in the current issue of the journal Gastroenterology.
“Certain bacterial populations correlated very strongly with increased fat in the liver during a restricted choline diet,” said Melanie Spencer, a doctoral student in bioinformatics at the University of North Carolina at Charlotte and the lead author on the paper. “To us, it’s an amazing result because you just
don’t see this clear a correlation in biological experiments in humans very often.”
The authors on the paper are Spencer, Anthony Fodor, Timothy Hamp and Robert Reid from the department of bioinformatics and genomics at UNC Charlotte, as well as Steven Zeisel and Leslie Fischer from the department of nutrition at the University of North Carolina at Chapel Hill.
Using a metagenomic technique that compares versions of a ribosomal RNA gene known to vary between bacterial groups, the researchers analyzed the genomes of the patients’ gut bacteria before, during and after the patients were put on a choline deficient diet. Because all patients consumed identical diets during the study, the researchers predicted that the initially distinct and complex communities of microbes in the patients’ intestinal tracts would react by becoming less distinct from each other. The researchers found instead that, though each of the patients’ bacterial communities did change a bit, each individual’s community still remained distinctive throughout the study.
“What we expected we might find would be that when we put the patients on exactly the same diets, everyone’s gut microbe mixture would begin to look similar, with the microbial communities converging. It did not happen – everybody was clearly individual throughout the entire study,” Spencer noted.
“So we also looked at how the patients’ microbes actually changed in pattern, even though they remained distinct from each other,” she said. “The patterns of change were very interesting. Some of the patterns were very distinct in themselves.”
The researchers noticed that among the numerous classes of bacteria present in each patient, variations in the populations of two particular groups seemed to correspond with variations between patients in the degree to which they developed a fatty liver during the period of dietary choline depletion.
“Those patients with the highest abundance of Gammaproteobacteria at the beginning of the study seemed to have the lowest fatty liver development. The ones with the least developed the most fatty liver,” Spencer noted. “Erysipeoltrichi showed exactly the opposite association, though this relationship was not quite as strong. So there seemed to be change going on in opposite directions.”
When the trends of Gammaproteobacteria abundance and Erysiptoltrichi scarcity were combined and related to fatty liver development, the relationship became even stronger.
Finally, the researchers factored in individual genetic variations that affect internal production of the nutrient choline and that should explain why some patients developed fatty liver and others did not. Surprisingly, the results showed that each person’s genetics did not entirely account for their fatty liver outcome. When the researchers modified the analysis to include the abundances of the two bacterial groups and each individual’s genetics, the correlation between fatty liver development and these three factors was nearly perfect. Further mathematical tests were performed to show that the correlations were not likely to be an artificial result of some bias hidden in the analysis.
“There was some concern that we were ‘over-fitting’ the model,” Spencer noted, “so we tested it out and ran a million permutations, altering the bug abundance and subject association, to see if we could identify how many actually showed a higher correlation by chance. What we found is that the p values still held up. We can have a lot of confidence in the result.”
The big question that remains for the team is why the two bacterial populations correlate so strongly to the development of fatty liver. Anthony Fodor, UNC Charlotte assistant professor of bioinformatics and the project’s director, sees a possible explanation, while warning against drawing specific conclusions without further study.
“We cannot yet assign cause and effect, but it implies that some bacteria are doing something that is making it easier for people to deal with a choline deficiency and for the liver to metabolize fat.”
Conversely, the bacteria whose high population levels correlate with disease may be somehow removing available forms of choline from digested food. Fodor explains that further study will be needed to answer those questions.
“We’re debating what the next step is,” he said. “In some ways, this is a very specialized experiment because we are inducing fatty liver in a very specific way. In the general population, fatty liver is induced in many, many ways and not everyone who has fatty liver has low choline.
“It’s probably like Alzheimer’s or cancer, where there are many different causes for a disease that displays a common phenotype. More research will be required to determine the extent to which bacterial populations play a role in fatty liver development in the general population, but our results strongly suggest that there may be a link in some people.”
Public release date: 1-Feb-2011
Want more efficient muscles? Eat your spinach
After taking a small dose of inorganic nitrate for three days, healthy people consume less oxygen while riding an exercise bike. A new study in the February issue of Cell Metabolism traces that improved performance to increased efficiency of the mitochondria that power our cells.
The researchers aren’t recommending anyone begin taking inorganic nitrate supplements based on the new findings. Rather, they say that the results may offer one explanation for the well-known health benefits of fruits and vegetables, and leafy green vegetables in particular.
“We’re talking about an amount of nitrate equivalent to what is found in two or three red beets or a plate of spinach,” said Eddie Weitzberg of the Karolinska Institutet in Sweden. “We know that diets rich in fruits and vegetables can help prevent cardiovascular disease and diabetes but the active nutrients haven’t been clear. This shows inorganic nitrate as a candidate to explain those benefits.”
In fact, up until recently nitrate wasn’t thought to have any nutritional value at all. It has even been suggested that this component of vegetables might be toxic. But Weitzberg and his colleague Jon Lundberg earlier showed that dietary nitrate feeds into a pathway that produces nitric oxide with the help of friendly bacteria found in our mouths. Nitric oxide has been known for two decades as a physiologically important molecule. It opens up our blood vessels to lower blood pressure, for instance.
The new study offers yet another benefit of nitrate and the nitric oxides that stem from them. It appears that the increased mitochondrial efficiency is owed to lower levels of proteins that normally make the cellular powerhouses leaky. “Mitochondria normally aren’t fully efficient,” Weitzberg explained. “No machine is.”
Questions do remain. The new results show that increased dietary nitrate can have a rather immediate effect. But it’s not yet clear what might happen in people who consume higher levels of inorganic nitrate over longer periods of time. Weitzberg says it will be a natural next step to repeat the experiment in people with conditions linked to mitochondrial dysfunction, including diabetes and cardiovascular disease, to see if they too enjoy the benefits of nitrates.
“Among the more consistent findings from nutritional research are the beneficial effects of a high intake of fruit and vegetables in protection against major disorders such as cardiovascular disease and diabetes,” the researchers concluded. “However, the underlying mechanism(s) responsible for these effects is still unclear, and trials with single nutrients have generally failed. It is tempting to speculate that boosting of the nitrate-nitrite-NO pathway may be one mechanism by which vegetables exert their protective effects.”
As an interesting aside, Weitzberg says that the benefits of dietary nitrates suggest that powerful mouthwashes may have a downside. “We need oral bacteria for the first step in nitrate reduction,” he says. “You could block the effects of inorganic nitrate if you use a strong mouthwash or spit [instead of swallowing your saliva]. In our view, strong mouthwashes are not good if you want this system to work.”
Size of airborne flu virus impacts risk, Virginia Tech researchers say
A parent’s wise advice to never go to a hospital unless you want to get sick may be gaining support from scientific studies on a specific airborne virus.
The results of a Virginia Tech study by environmental engineers and a virologist on the risk of airborne infection in public places from concentrations of influenza A viruses is appearing today in the on-line, Feb. 2 issue of the United Kingdom’s Journal of the Royal Society Interface.
Linsey Marr, associate professor of civil and environmental engineering at Virginia Tech, http://www.cee.vt.edu/people/lmarr.html and her colleagues, Wan Yang, of Blacksburg, Va., one of her graduate students, and Elankumaran Subbiah, a virologist in the biomedical sciences and pathobiology department of the Virginia-Maryland Regional College of Veterinary Medicine, http://www.vetmed.vt.edu/org/dbsp/faculty/subbiah.asp conducted their research in a health center, a daycare facility, and onboard airplanes.
“The relative importance of the airborne route in influenza transmission—in which tiny respiratory droplets from infected individuals are inhaled by others—is not known,” Marr, who received a National Science Foundation CAREER Award to pinpoint sources of unhealthy air pollutants, said.
What is known is that influenza A viruses are “transmitted through direct contact, indirect contact, large respiratory droplets, and aerosols that are left behind by the evaporation of larger droplets,” they reported in the journal. “The aerosol transmission route is particularly controversial since there is scant proof of infection mediated by virus-laden aerosols, partly due to the difficulties in studies involving human subjects and partly due to the challenges in detecting influenza A viruses in ambient air.”
What happens is an infected person might cough or sneeze or just be engaged in conversation, and release the viruses into the air. However, these aerosols are quickly diluted to very low concentrations by the surrounding air.
Marr said, “Few studies have measured actual concentrations of influenza A viruses in air and determined the size of influenza-laden particles. Size is important because it determines how long the particles will remain suspended in the air before being removed due to the forces of gravity or other processes.”
To conduct their studies, the Virginia Tech researchers collected samples from a waiting room of a health care center, two toddlers’ rooms and one babies’ area of a daycare center, as well as three cross-country flights between Roanoke, Va., and San Francisco, Ca. They collected 16 samples between Dec. 10, 2009 and Apr. 22, 2010.
“Half of the samples were confirmed to contain aerosolized influenza A viruses,” Marr said. “In the others, it is possible that no infected individuals were present.”
Marr added, “The average concentration was 16,000 viruses per cubic meter of air, and the majority of the viruses were associated with fine particles, less than 2.5 micrometers, which can remain suspended for hours. Given these concentrations, the amount of viruses a person would inhale over one hour would be adequate to induce infection.”
Subbiah indicated that most studies of airborne transmission of influenza viruses in animals examined the ability of infected animals to transmit the infection to susceptible in-contact animals. How the ambient environment affects the virus after release from the infected host until it reaches the recipient host is relatively unknown. Results of the study show that under defined conditions of humidity and temperature, viruses may remain suspended in air.
Incorporating the concentrations of influenza A viruses and breathing rates, Marr and her colleagues estimated the inhalation dose incurred by someone in the same room and concluded that it was sufficient to induce infection.
“As a whole,” the three authors concluded in the Journal of the Royal Society Interface, “our results provide quantitative support for the possibility of airborne transmission of influenza in indoor environments.”
Public release date: 2-Feb-2011
Why folic acid may prevent a first heart attack, but not a second
A perplexing medical paradox now has an explanation according to research undertaken at Barts and The London School of Medicine and Dentistry and published in the current issue of the Public Library of Science. The paradox is that taking folic acid, a B vitamin, lowers homocysteine in the blood which, epidemiological evidence indicates, should lower the risk of heart attack, but clinical trials of folic acid have not shown the expected benefit.
Theexplanationis surprisingly simple; lowering homocysteine prevents platelets sticking, which stopsblood clots…something aspirin also does, so if people in the trials were already taking aspirintherewouldbe no extra benefit in lowering homocysteine with folic acid.
Aspirin was in fact widely used by participants in the trials because they were mainly conducted in patients who had already had a heart attack or other cardiovascular diseases.
Research led by Dr David Wald at the Wolfson Institute of Preventive Medicine at Barts and The London School of Medicine and Dentistry showed that there was a difference in the reduction in heart disease events between the five trials with the lowest aspirin use (60 per cent of the participants took aspirin) and the five trials with the highest use (91 per cent took aspirin). The observed risk reduction was six per cent but it would have been 15 per cent if no one had been taking aspirin. Research was based on 75 epidemiological studies involving about 50,000 participants and clinical trials involving about 40,000 participants.
“The explanation has important implications,” said Dr David Wald, the lead author of the paper. “The negative clinical trial evidence should not close the door on folic acid – folic acid may still be of benefit in people who have not had a heart attack because they will generally not be taking aspirin”.
Public release date: 4 -Feb- 2011
Restrictive Diet May Reduce ADHD Symptoms
By Serena Gordon
THURSDAY, Feb. 3 (HealthDay News) — A special restrictive diet may significantly reduce symptoms of attention-deficit hyperactivity disorder (ADHD) in young children, a new study suggests.
When children between the ages of 4 and 8 were placed on a diet containing no processed foods for five weeks, ADHD symptoms diminished in 78 percent of them. And, when suspected trouble foods were reintroduced into the diet, two-thirds of the children experienced a relapse in symptoms.
“A strictly supervised restricted elimination diet is a valuable instrument to assess whether ADHD is induced by food,” wrote the study authors. “We think that dietary intervention should be considered in all children with ADHD, provided parents are willing to follow a diagnostic restricted elimination diet for a five-week period, and provided expert supervision is available,” they concluded.
Results of the study are published in the Feb. 5 issue of The Lancet.
ADHD is a common childhood disorder, according to the National Institute of Mental Health (NIMH). Children with ADHD have trouble paying attention, focusing and can be hyperactive. Parents have long suspected that sugary foods might be a culprit in inducing symptoms, but there’s not a lot of evidence to support this theory, according to the NIMH. However, food additives and preservatives have recently been singled out as possibly having an effect on children’s behavior, though the evidence isn’t yet conclusive.
Since some children have negative physical reactions to certain foods — such as eczema, asthma and gastrointestinal problems — that affect different organ systems, it has been suggested that foods may also affect the brain in a way that results in adverse behavior, according to information in the study.
To test this theory, the researchers recruited 100 children from Belgium and the Netherlands. The children were between the ages of 4 and 8, and all had been diagnosed with ADHD. Most of the children were boys.
The children were randomly assigned to one of two groups. One group was placed on the restrictive elimination diet, and the other group served as a control group and received advice on healthy eating.
The restrictive diet began with a diet called the “few foods diet,” which includes just rice, meat, vegetables, pears and water. The researchers then complemented this diet with certain foods, such as potatoes, fruits and wheat. The restrictive diet lasted for five weeks.
During the next four weeks, kids in the restricted diet group received two food challenge diets, in which certain foods were reintroduced into the diet. The researchers selected foods that were considered both low- and high-IgG foods.
IgG is an antibody made by the immune system that some alternative medicine practitioners believe is linked to food hypersensitivities; however, IgG testing is controversial among many mainstream physicians and even some naturopaths, according to background information in the study.
Some complementary medicine practices test for IgG and recommend eliminating foods high in IgG, explained Dr. Jaswinder Ghuman, who wrote an accompanying editorial in the same issue of the journal.
Forty-one children completed the restrictive phase of the diet. Of those, 78 percent had a reduction in their ADHD symptoms, compared with no improvement in the controls. Nine children (22 percent) didn’t respond to the diet. On an ADHD symptom scale that ranges from 0 to 72 points, with a higher score indicating more severe symptoms, the average reduction was 24 points, according to the study.
Thirty children who had shown a response on the restrictive diet went on to the challenge test. Nineteen of those children had a relapse in symptoms on the challenge test. What’s more, it didn’t appear to matter if
the children with challenged with a low- or high-IgG food.
“Measuring IgG levels in kids doesn’t seem helpful,” Ghuman said, but it does look as if the elimination diet may help some children.
“If parents have noticed that a child’s behavior seems to get worse with certain foods, it may be worth considering,” said Ghuman, who is an associate professor of psychiatry and pediatrics at the University of Arizona in Tucson.
“But, for this diet to work, you have to be very consistent with it, and you have to pay attention to nutrition. It should be done under the supervision of a primary care doctor, and if possible, a dietician,” she advised.
Ghuman said that this study doesn’t answer a number of questions, such as whether or not the elimination diet reduces symptoms long-term. And, she added, that clinical practice shouldn’t be changed based on the results of one study.
Dr. Andrew Adesman, chief of developmental and behavioral pediatrics at the Steven and Alexandra Cohen Children’s Medical Center of New York in New Hyde Park, echoed Ghuman’s concerns.
“Since none of the children stayed on the diet beyond five weeks, it is hard to know if this dietary intervention offers sustained benefit,” he said, adding, “Since it is more difficult to enforce restricted diets in older children, this approach may not be suitable for the majority of older children with ADHD.”
Adesman also pointed out that this study is only applicable to children with ADHD, not to children who had ADD without the hyperactivity component.
These reports are done with the appreciation of all the Doctors, Scientist, and other Medical Researchers who sacrificed their time and effort. In order to give people the ability to empower themselves. Without the base aspirations for fame, or fortune.
Just honorable people, doing honorable things.