Thursday, May 29, 2014

H10N8 strain of bird flu is 'not a current threat to public health

The recent H10N8 strain of bird flu is unlikely to result in a public health threat without further mutations in the virus that would allow it to spread between humans. H10N8 is the latest in a line of continually evolving avian influenza viruses that can cause serious, potentially fatal disease in humans. Similar bird flu strains, such as H7N9, can cause severe pneumonia, acute respiratory distress syndrome, impaired liver or renal function, septic shock, muscle breakdown and brain disease. Initial symptoms include fever, muscle pains, cough, wheeze, headache and general malaise. H10N8 was first detected in humans in December 2013. The virus was found in a 73-year-old woman from Nanchang City in China, after she was admitted to the hospital with symptoms of severe pneumonia and fever. She died 9 days after the onset of illness. There have since been two further cases of the infection in humans, including one more death from the virus. Earlier this year, a report in The Lancet warned of the potential of a pandemic, with experts writing: "A H5N1 virus infection in Hong Kong in 1997 preceded the next 17 cases by 6 months, so more human cases of H10N8 infection might occur in the future. The pandemic potential of this novel virus should not be underestimated." Assessing the binding properties of avian flu strains At the Medical Research Council National Institute for Medical Research (MRC-NIMR), researchers have been investigating what potential the H10 family of viruses have for causing a pandemic. woman sneezing The virus will need to change receptor binding preference for more efficient transmission to humans. Assessing this requires the researchers to examine the molecular structure of the virus and see how it is able to bind to receptors. The researchers found that the H10 viruses have the same binding characteristics of other pandemic flu strains, such as H1 (the 1918 Spanish flu). There are also similarities in binding properties between H10 and the H7 viruses that have infected humans. Where the H10 deviates from the H1 and H7 viruses, though, is in its preference of receptor. H1 and H7 viruses bind up to 100 times more strongly to human receptors than avian receptors. However, the H10 viruses bind with avian receptors about 150 times more strongly than with human receptors. "We pay special attention to viruses that show changes in receptor binding preference," says Dr. John McCauley, director of the World Health Organization (WHO) Influenza Centre at the MRC-NIMR, "because it is likely to be a requirement for more efficient transmission to humans." "A change in receptor binding is the essential first step in generating a pandemic virus," asserts Dr. McCauley, who adds that the MRC-NIMR results illustrate "the sophisticated scientific basis of monitoring influenza viruses and the importance of the WHO global influenza surveillance for public health." Written by David McNamee

Tuesday, May 27, 2014

Caffeine may boost long-term memory

Numerous studies have suggested that caffeine has many health benefits. Now, new research suggests that a dose of caffeine after a learning session may help to boost long-term memory. This is according to a study published in the journal Nature Neuroscience. The research team, led by Daniel Borota of the Johns Hopkins University in Baltimore, notes that although previous research has analyzed the effects of caffeine as a cognitive enhancer, whether caffeine can impact long-term memory has not been studied in detail. To find out, the investigators analyzed 160 participants aged between 18 and 30 years. On the first day of the study, the participants were shown pictures of different objects and were asked to identify them as "indoor" or "outdoor" items. Soon after this task, they were randomized to receive either 200 mg of caffeine in the form of a pill, or a placebo tablet. The next day, the participants were shown the same pictures as well as some new ones. The researchers asked them to identify whether the pictures were "new," "old" or "similar to the original pictures." 200 mg of caffeine 'enhanced memory' From this, the researchers found that subjects who took the caffeine were better at identifying pictures that were similar, compared with participants who took the placebo. However, the researchers note that both groups were able to accurately distinguish whether pictures were old or new. Coffee being poured into a cup which is sitting on a bed of coffee beans New research suggests that consuming 200 mg of caffeine a day may boost long-term memory. The team conducted further experiments using 100 mg and 300 mg doses of caffeine. They found that performance was better after the 200 mg dose, compared with the 100 mg dose, but there was no improvement after the 300 mg of caffeine, compared with 200 mg. "Thus, we conclude that a dose of at least 200 mg is required to observe the enhancing effect of caffeine on consolidation of memory," the study authors write. The team also found that memory performance was not improved if subjects were given caffeine 1 hour before carrying out the picture identification test. They investigators say there are many possibilities as to how caffeine may enhance long-term memory. For example, they say it may block a molecule called adenosine, preventing it from stopping the function of norepinephrine - a hormone that has been shown to have positive effects on memory. They note that further research should be conducted to better understand the mechanisms by which caffeine affects long-term memory. They add: "Given the widespread use of caffeine and the growing interest in its effects both as a cognitive enhancer and as a neuroprotectant, these questions are of critical importance." Potential benefits and risks of caffeine consumption According to the latest figures from the US Food and Drug Administration (FDA), the average American consumes 300 mg of caffeine a day. The main sources of the compound are coffee, tea and soft drinks. Many studies have suggested that caffeine offers health benefits. Last year, Medical News Today reported on a study suggesting that caffeinated drinks may reduce the risk of liver disease, while another study says drinking 2-4 cups of coffee a day may reduce suicide risk. But it is not all good news. One study suggests that the stimulant is able to disrupt sleep patterns hours after consuming it, while another proposes that caffeine from energy drinks may alter heart function. Written by Honor Whiteman

Monday, May 26, 2014

How Safe Is Splenda (Sucralose)?

Splenda (sucralose) is being downgraded from "safe" to "caution" after an Italian animal study linked sucralose to a higher risk of developing leukemia. The Center for Science in the Public Interest (CSPI) says it awaits the Italian study's review before deciding what long-term safety grade to assign to Splenda in its Chemical Cuisine guide to food additives. Hundreds of millions of people globally use artificial sweeteners, which are commonly found in a wide range of food and drinks, including food for diabetes, cakes, milkshakes, soft drinks, and even medications. The steadily growing problem of obesity and type 2 diabetes in developed and middle income countries has led to rising demand for reduced-calorie foods and drinks. However, the growth of the artificial-sweetener market has brought with it concerns among consumers regarding the potential health consequences. Italian study linked a lifetime of sucralose consumption to leukemia risk Dr. Morando Soffritti, director of the Ramazzini Institute in Bologna, Italy, and team fed 843 laboratory mice varying doses of sucralose from when they were fetuses until they died. Post-mortems showed an association between leukemia risk and lifetime sucralose consumption - the more sucralose they consumed, the higher their risk of leukemia. Dr Soffritti said: "Our early studies in rats showed increases in several types of cancer, and, in our most recent aspartame studies, we observed a statistically significant increase of liver and lung tumors in male mice. This shows aspartame causes cancer in various places of the body in two different species. Health concerns over aspartame are leading consumers to switch to the widely promoted alternative: sucralose. Now that we have found evidence of a link between sucralose and cancer in mice, similar research should be urgently repeated on rats, and large scale observational studies should be set up to monitor any potential cancer risk to human health." Dr Soffritti says that children and pregnant mothers should avoid consuming artificial sweeteners until appropriate studies clearly show there is no cancer risk. On an online communiqué, CSPI added that the only long-term feeding studies on sucralose in animals, before the Italian one, were conducted by Johnson & Johnson, the makers of Splenda. As things stand at the moment, these are the gradings CSPI gives to artificial sweeteners: Splenda - caution Saccharin - avoid Aspartame - avoid Acesulfame potassium - avoid Rebiana - safe CSPI adds that it would be useful to have further testing done on rebiana. CSPI executive director Michael F. Jacobson, said: "Sucralose may prove to be safer than saccharin, aspartame, and acesulfame potassium, but the forthcoming Italian study warrants careful scrutiny before we can be confident that the sweetener is safe for use in food." Diet sodas probably still better than regular ones Even though concerns exist regarding the health risks associated with artificial sweeteners, CSPI believes people are better off drinking diet rather than regular sugar-sweetened sodas. The CSPI says that the health consequences from regularly drinking sugar-laden soft drinks, which include obesity, gout, tooth decay, heart disease, and type 2 diabetes, are probably greater. Water is best - soft drinks with any kind of natural or artificial sweetener commonly contain food dyes and caramel coloring that are contaminated with 4-methylimidazole, a carcinogen. CSPI encourages consumers to drink water, seltzer water (soda water, effervescent mineral water), flavored unsweetened waters, unsweetened iced tea, or seltzer mixed with natural fruit juice. New sweeteners enter CSPI's Chemical Cuisine guide CSPI has included some new natural sweeteners in its Chemical Cuisine guide: Monkfruit extract (also known as Luo Han Guo or Lo Han Kuo) - contains mogrosides. Mogrosides are 200 times sweeter than sugar. However, they can leave a licorice-like aftertaste. Monkfruit extract currently has a "caution" rating because it has not been tested scientifically. Monatin - derived from a South African shrub. Monatin is said to be 3,000 times sweeter than sugar. Monatin currently has a "caution" rating because it has not been tested scientifically. Sucralose is about 600 times as sweet as table sugar (sucrose), three times as sweet as aspartame, and twice as sweet as saccharin. Written by Christian Nordqvist