India / Health & Beauty
How Salmonella bacteria infect salad leaves
03.09.2008 06:31
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A new study has revealed how Salmonella bacteria can cause food poisoning by attaching to salad leaves. The study shows how some Salmonella bacteria use the long stringy appendages they normally use to help them ''swim'' and move about to attach themselves to salad leaves and other vegetables, causing contamination and a health risk. Usually food poisoning from Salmonella and E. coli is linked with eating contaminated bovine or chicken products, as the pathogens live in the guts of cows and the guts and egg-ducts of chickens, and contamination of meat can occur during the slaughtering process. But, many of the recent outbreaks of food poisoning have been attributed to contaminated salad or vegetable products, and more specifically, pre-bagged salads. Led by Professor Gadi Frankel from Imperial College London, the new research has uncovered the mechanism used by one particular form of Salmonella called Salmonella enterica serovar Senftenberg, to infect salad leaves, causing a health risk to people who eat them. This breakthrough would help scientists in developing new methods of preventing this kind of contamination and the sickness it causes. Scientists know that Salmonella and E. coli O157 - a strain of E. coli that can cause serious sickness in humans - can spread to salads and vegetables if they are fertilised with contaminated manure, irrigated with contaminated water, or if they come into contact with contaminated products during cutting, washing, packing and preparation processes. However, they do not understand how the pathogens managed to bind to the leaves, until now. The researchers have now found that Salmonella enterica serovar Senftenberg bacteria have a secondary use for their flagella - the long stringy ''propellers'' they use to move around. The flagella flatten out beneath the bacteria and cling onto salad leaves and vegetables like long thin fingers. For testing this observation, the scientists genetically engineered salmonella without flagella in the lab and found that they could not attach themselves to the leaves, and the salad remained uncontaminated. "Discovering that the flagella play a key role in Salmonella''s ability to contaminate salad leaves gives us a better understanding then ever before of how this contamination process occurs. Once we understand it, we can begin to work on ways of fighting it," said Frankel. The team will now look at the extent to which different types of salad leaves are affected by salmonella. Frankel explained that some types of leaves are less susceptible to salmonella contamination that others. "If we can find out what factors affect susceptibility, we may be able to develop new technologies to harness the ''immunity'' found in some salad leaves to protect others from contamination," he said. However, Frankel said that even though such a small minority of cases are currently linked to salads, the numbers are likely to increase in coming years. In a previous study, the same team of researchers discovered the mechanism by which E. coli 0157 binds to salad leaves. They have shown that E. coli O157 bacteria use short needle-like filaments, which are normally used to inject bacterial proteins into human cells, to attach them to salad leaves, causing contamination and a risk of transmission via the food chain to humans. The study is presented at the 21st International ICFMH Symposium ''Food Micro 2008'' conference in Aberdeen. (ANI)
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Gene behind inflammatory bowel diseases in kids identified
03.09.2008 06:31
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In a study of inflammatory bowel diseases in children like Crohn''s disease and ulcerative colitis, scientists have identified a gene, called tumor necrosis factor receptor superfamily member 6B (TNFRSF6B) that influences whether children get these diseases early in life. The findings of the study by an international team also points to a potential new target for treatment. Co-first author of the study, Subra Kugathasan, MD, said that while scientists have earlier found several genes that influence susceptibility to the two diseases, this is the first to focus on inflammatory bowel disease (IBD) with childhood onset. Kugathasan''s future research will focus on discovery of additional IBD genes and in depth study of how these genes influence disease onset and progression. "Our novel candidate gene is in the same inflammatory pathway as some other susceptibility genes, so it may represent an accessible target for treatment," Nature quoted Kugathasan, as saying. Kugathasan said that both genetics and the environment have an effect on the risk of getting inflammatory bowel disease. If one identical twin suffers from Crohn''s disease, the other has a 60 percent probability of getting it too. However, he noted that the incidence of disease has drastically increased over the last half century. He also suggested a key role of the environment in disease development. Smoking is an environmental factor that is particular strong in increasing the risk of Crohn''s disease. "We have to conclude that the interactions between genetics and environment are responsible for most cases," he said. The study compared the DNA of more than 1,000 children diagnosed with inflammatory bowel diseases at the average age of 11 with 4,250 controls (disease-free children), and confirmed the findings in a larger set of patients established by the British Wellcome Trust Case Control Consortium. They used gene chip microarray technology to scan thousands of one-letter alternative genetic "spellings" -- known to geneticists as single nucleotide polymorphisms (SNPs)-- spread throughout the patients'' DNA. Most of the SNPs made little difference when it came to affecting the risk of inflammatory bowel disease, but a few stood out, and two had not been seen before. One new SNP led the scientists to TNFRSF6B, whose activity they found was associated with the degree of inflammation in the colon. The function of the second SNP is still under investigation. TNFRSF6B encodes a protein that lengthens the duration of an immune response by regulating the longevity of activated white blood cells. Kugathasan said that a related protein, tumor necrosis factor alpha, is the target of an existing antibody treatment for inflammatory bowel disease. This suggests that antibodies to TNFRSF6B could also be helpful in controlling the disease, he says. The study was published online by the journal Nature Genetics. (ANI)
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Men with high blood calcium levels at ‘high fatal prostate cancer risk’
03.09.2008 06:31
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Men who have high levels of calcium in their blood are more likely to get fatal prostate cancer, US researchers have said. According to scientists, the new findings suggest that a simple blood test may identify men at high risk for the most dangerous prostate tumours, and there already are drugs available that cut calcium levels in the bloodstream. To reach the conclusion, the researchers tracked 2,814 men in a government health survey in which they gave blood samples that revealed calcium levels. The study found that the men in the top third of blood calcium levels had 2.68 times the risk of developing fatal prostate cancer later in life compared to those in the bottom third. "If serum calcium really does increase your risk for fatal prostate cancer, that''s wonderfully exciting because serum calcium levels can be changed," the Mirror quoted Gary Schwartz of Wake Forest University School of Medicine, who helped lead the study, as saying in a telephone interview. "One way to think of it is to think of the tremendous advances in the control of cardiovascular disease that occur from understanding that things like serum cholesterol predict heart attack," Schwartz added. Doctors have struggled to find ways to predict if a man who gets prostate cancer will have a tumour that poses little danger, as is often the case, or one that is a killer. Blood calcium was not very predictive of whether a man would get nonlethal prostate cancer, but was highly predictive of whether a man would get a fatal case, the researchers wrote in the American Association for Cancer Research''s journal Cancer Epidemiology, Biomarkers & Prevention. (ANI)
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Atkins diet, Weight Watchers plan are ''the best way to shed extra flab''
03.09.2008 06:31
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Forget starving and the gruelling gym session, just follow the Atkins diet or the calorie-counting Weight Watchers plan, and you will be successful in your war against love handles, according to a new study. A study of four popular weight loss plans showed that dieters lost an average of 11 pounds over two months by following the Atkins plan, while the calorie-counting Weight Watchers method helped people shed more than 10 pounds. Individuals who followed the Slim Fast Plan and a Rosemay Conley diet plan both lost on average between eight and nine pounds. Despite claims that the low-carbohydrate Atkins diet could be dangerous due to its reliance on red meat and fat, researchers also found that all the diets tested were healthy. Helen Truby worked with a team of academics from United Kingdom universities who studied the different diet plans. She said: "These disappointing findings suggest that people remain resistant to the advice to ''eat more fruit and vegetables'', even when they are advised to as part of a modified weight loss programme". However, the researchers said: "Atkins dieters tended to have a reduction in iron and niacin, probably due to a fall in the intake of cereal and flour, which is fortified in the UK. They also had a generally low intake of dietary fibre overall, which may have implications for bowel health in the longer term". They also said that popular slimming programmes do result in reduced energy intake while providing enough nutrients. She described how the randomised controlled trial "provides reassuring and important evidence for the effectiveness and nutritional adequacy of the four commercial diets tested". The researchers asked 293 people from five regional areas around the UK to keep a diary of their food intake before and during the two-month diet period. There was also a control group who continued to eat as normal. They found that following any of the four diets did result in a drop in energy intake. The diets all resulted in a significant drop in body weight compared to the non-dieting controls, but there was no significant difference between the diets in the amount of weight lost. Based on their results, the authors suggest "commercial companies work in partnership with health professionals to identify high-risk clients and provide them with dietary advice that is tailored to their nutritional requirements". The study was published in BioMed Central''s open access Nutrition Journal. (ANI)
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Colorectal cancer screening should begin at age 50
03.09.2008 06:30
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A new study has suggested that screening for colorectal cancer screening should start at age 50. In the study, researchers at the John Hopkins University found that colorectal adenomas - the precursor polyps in virtually all colorectal cancers - occur infrequently in younger adults but the rate sharply increases after age 50. Therefore, the researchers emphasize the importance of colonoscopies, which view the entire colon, for the prevention of colorectal cancer beginning at age 50. "While colorectal polyps are rare in adults aged 30 to 50, our study reveals an increase in polyp prevalence with age and a dramatic increase in colorectal adenoma incidence occurring in adults over the age of 50," said Francis M. Giardiello, MD, of The John Hopkins University and lead author of the study. "Understanding the natural occurrence of colorectal polyps, especially in younger adults, is important to the development of colorectal cancer prevention strategies," Giardiello added. During the study, researchers found that the prevalence of colorectal polyps in younger adults increased from 1.72 percent to 3.59 percent from age 30 to 50. This rate sharply increased after age 50 with the prevalence of polyps ranging from 10.1 to 12.06 percent in the sixth and ninth decade, respectively. The study results quantified the number of adenomas typically found in people under the age of 50. The researchers said that it is important to note that those with two or more adenomas under 50 years of age represent unusual individuals who might merit closer colonoscopic surveillance for subsequent adenoma development. In younger adults, adenomas were more prevalent in Caucasians compared to African Americans; however, in older adults, the reverse was true. Regardless of age, adenomas were more prevalent in men than women. In the general population, left-sided adenomas are most common, but among older adults (age 50+), who have more adenomas, there is a relatively greater prevalence of right-sided adenomas. African Americans in both age groups had predominately right-sided polyps. Colonoscopy, which provides the most comprehensive view of the colon, is the definitive test for colorectal cancer screening. Colonoscopies allow gastroenterologists to view the entire colon and rectum for polyps or cancer and during the same exam remove pre-cancerous polyps. It is the test most gastroenterologists recommend as the single best screening exam for colorectal cancer. It is the only method that combines both screening and prevention (by removal of pre-cancerous polyps). The study was published in Clinical Gastroenterology and Hepatology, the official journal of the American Gastroenterological Association (AGA) Institute. (ANI)
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One in three Brits face undiagnosed heart risk
03.09.2008 02:30
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A major UK study has found that one in three people with a high risk of developing cardiovascular disease (CVD) over the next 10 years have not been diagnosed. The study of more than 71,000 men and women, which was conducted by Oxford University, showed that the shortfall in identifying people at high risk is greatest when it comes to middle-aged men. "The aim of our study was to estimate how many people were likely to develop CVD over the next ten years" said lead author Professor Andrew Neil from the Division of Public Health and Primary Care. "Our findings reinforce the need for a national CVD risk assessment programme and we welcome the announcement by the Department of Health earlier this year that plans are being put in place to institute primary care checks for people aged from 40 to 74," he added. The study suggests that 7.9 million people in the UK have already been diagnosed with CVD or have a medically recognised risk of developing the disease in the next ten years. However, there are a further 2.8 million men and 900,000 women who face a high risk but have not been diagnosed. This means that they have not received the treatment and advice that could prevent them from developing CVD. For the study, Neil and his colleagues screened 71,037 people aged 18 and over in 35 towns and cities in England, Wales and Scotland. They found that overall, 20 per cent of the men and six per cent of the women had a high risk of developing CVD over the next ten years. The risk was much higher in the over 50 age group. "Our research found that 75 per cent of men and 45 per cent of women who were over 50 already had CVD or diabetes, were taking cholesterol or blood pressure drugs or were at high risk of developing CVD" said Neil. "We were reassured to discover that 60 per cent of them had already been identified by their family doctor or another primary health care professional. However, the challenge now is to identify the other 40 per cent who are at high risk of developing the disease but remain undiagnosed. "When we looked at gender differences in this age group, we found that only 47 per cent of men had been identified as having a high CVD risk, considerably lower than the 72 per cent of women identified, possibly because women are more likely to seek medical advice. "These figures suggest that there is significant unmet need in the UK and points to the need for a national assessment programme to detect those individuals who haven''t already been identified," he added. The study is published in the September issue of IJCP, the International Journal of Clinical Practice. (ANI)
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New method to spot a heart attack soon after it occurs
03.09.2008 02:30
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Researchers at Massachusetts General Hospital, Charlestown, have developed a new method for early detection of a heart attack – metabolite profiling. To test the method, Robert Gerszten and colleagues conducted a study, in which blood samples were collected before and after a number of patients with the heart condition hypertrophic cardiomyopathy were treated using a medical procedure that creates a small controlled heart attack. The samples were analyzed using the new method. Changes in a number of metabolites were observed only 10 minutes after the planned heart attack. The researchers observed this same signature of changes in a second series of patients undergoing the same procedure and in a number of patients spontaneously having a heart attack. According to the researchers, no other method can detect changes indicating a heart attack so soon after it has occurred, and hope that their approach can be used to improve early detection of a heart attack. (ANI)
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Brain scans can reveal best times optimal times to multi-task
03.09.2008 02:30
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While the significance of multi-tasking is increasing day by day, researchers at the University of New Hampshire say that it is possible to predict when a person will prove to be an efficient multi-tasker. The researchers say that they scanned some people’s brains using functional magnetic resonance imaging (fMRI), and were able to predict when the subjects would be poor multi-taskers and optimal multi-taskers. "We typically sacrifice efficiency when we multitask. However, there are times when we''re quite good at it. Unfortunately, not much has been known about how to predict when these periods of time will occur," said Andrew Leber, assistant professor of Psychology. In their study report, published in the Proceedings of the National Academy of Sciences, the researchers say that the changes in performance were more dramatically preceded by changes in the participants'' brain activity patterns. Higher levels of activity in brain regions such as the basal ganglia, anterior cingulate cortex, prefrontal cortex, and parietal cortex corresponded to better multi-tasking performance. "What is so striking about this result is that brain activity predicted multitasking performance before participants even knew whether they would be asked to switch or repeat tasks," Leber said. Although these findings indicate that brain imaging may be useful for maximizing productivity in people’s daily lives, the researchers agree that they do not provide a truly practical solution quite yet. "Obviously, the average person can''t bring an fMRI scanner to work. It may take more time before our research translates to real-world benefits for each of us," Leber said. However, the researchers insist that their study may inform scientists'' understanding of neurological disorders like Parkinson''s disease, which is marked by degeneration of the basal ganglia. While it is commonly known that Parkinson''s patients experience deficits in controlling movement, multi-tasking also is adversely affected. "We''ve known that multitasking suffers when the physical makeup of the basal ganglia degenerates over time, as in Parkinson''s disease. However, the current study shows that even in healthy adults, short-term changes in the basal ganglia also impact multitasking," Leber said The researchers say that this observation opens new potential avenues in studying normal brain functioning to help provide a more complete picture of the disordered functioning in Parkinson''s disease. (ANI)
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Analysis begins on Phoenix Lander’s deepest soil sample
03.09.2008 02:30
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Scientists have begun to analyze a sample of soil delivered to NASA’s Phoenix Mars Lander’s wet chemistry experiment from the deepest trench dug so far in the Martian arctic plains. The Lander’s robotic arm on Sunday sprinkled a small fraction of the estimated 50 cubic centimeters of soil that had been scooped up from the informally named “Stone Soup” trench on Saturday, the 95th day of the mission. The Stone Soup trench, in the left portion of the Lander’s active workspace, is approximately 18 centimeters (7 inches) deep. “This is pretty exciting stuff and we are anxious to find out what makes this deeper soil cloddier than the other samples,” said Doug Ming, a Phoenix science team member from NASA’s Johnson Space Center, Houston. The surface of the vast arctic plain where Phoenix landed on May 25 bears a pattern of polygon-shaped small hummocks, similar to some permafrost terrain on Earth. Scientists are particularly interested in the new sample because it is the first delivered to an analytical instrument from a trench on the margin between two of the polygons, where different material may collect than what has been analyzed from near the center of a polygon. Seen inside Phoenix’s scoop, the sample material from the bottom of the trench displayed clumping characteristics somewhat different from other cloddy soil samples that have been collected and examined. A series of images of fresh soil dug and discarded from Stone Soup trench have given some clues to the composition of the sample. While spectral observations have not produced any sign of water-ice, bigger clumps of soil have shown a texture that could be consistent with elevated concentration of salts in the soil from deep in the trench. The Lander’s wet chemistry laboratory can identify soluble salts in the soil. (ANI)
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Gene behind stroke-inducing vascular malformations uncovered
03.09.2008 02:30
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Scientist at the University of California, San Francisco (UNSF) say that irregularities in a constantly active Notch gene in endothelial brain cells may cause a vascular disorder that causes stroke. The researchers say that their experiments on mice are the first to provide information on both the progression and regression of the brain disorder BAVM, in which arteries and veins get connected directly rather than through capillaries. The direct connection produces enlarged, tangled masses of vessels that are prone to hemorrhagic rupture, bleeding, and stroke. During the study, the researchers used genetic tools to “turn on” the Notch gene, which induced BAVM. When the researchers turned the gene off, the mice exhibited full recovery from the disease’s progression. “This was exciting. The activated Notch gene caused BAVM in all of the mice, making it an unprecedented, potent molecular lesion in the induction of the pathology. Furthermore, we found that repression of the gene in already-ill mice led to their recovery,” said Rong Wang, senior author on the study, associate professor and director of the Laboratory for Accelerated Vascular Research and Mildred V. Strouss Endowed Chair in Vascular Surgery at UCSF. Patrick A. Murphy, lead author on the paper and a graduate student from the UCSF Biomedical Science Program, added: “Our study offers hope for future treatments because even the effects of stroke such as paralysis and ataxia, or loss of muscle coordination, were reversed once we turned off Notch. This pathway has not yet been implicated in human disease, so these findings prompted our ongoing research into Notch signaling and allow us to examine the cellular and molecular mechanisms of BAVM.” The researchers believe that the knowledge gained about the development of BAVM may also be helpful in understanding the process of blood vessel disease in other organs like the lung and liver. "In the future, we may be able to inhibit or even reverse the disease process," said Tyson Kim, co-author on the paper and a bioengineering graduate student from the UCSF MD/PhD combined program, working with Wang. The researchers now consider Notch a strong candidate as a key regulator of human BAVM, and are undertaking additional research to find the disease’s cause. Besides studying disease progression and regression in mouse models, the researchers are also looking at the gene’s role in human AVMs by examining levels of Notch signalling pathway molecules in surgical tissue samples. “Although more work needs to be done to determine whether the research can be applied to clinical practice and whether up-regulation of Notch causes BAVM and stroke in humans, identifying the role of this pathway offers hope for developing treatments for this and other related diseases,” Wang said. The study has been published in the Proceedings of the National Academy of Sciences. (ANI)
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