https://www.eurekalert.org/pub_releases/2016-10/uoh-vec102516.php
Public Release: 26-Oct-2016
Vitamin E can modify the risk of pneumonia in some older men depending on their lifestyle
University of Helsinki
Many people have been advised to take vitamin supplements to boost their immune systems. However, a recent study published in the British Journal of Nutrition found that taking vitamin E supplements led to an increased risk of pneumonia for more than one in four older men (28%) who smoked and did not exercise. However, the opposite effect was true for older men who exercised and did not smoke - in that vitamin E actually decreased their risk of contracting pneumonia.
The findings of this study - which focused on men aged 50 to 69 years old at the baseline of the trial- are particularly striking because analyses in nutritional epidemiology usually assume a uniform effect of a nutrient. However, the author of the study - Dr. Harri Hemilä of the University of Helsinki, Finland - found that the effect of vitamin E on health outcomes may depend on various characteristics of people and their lifestyles. Therefore, a single universal estimate of the vitamin E effect might be substantially misleading for some population groups.
•••••
Drawing on the I2 statistic for the first time for this type of analysis, Dr. Hemilä concluded that nearly all variation in the vitamin E effect on pneumonia risk over five subgroups was explained by true differences in the vitamin E effect rather than by chance variation.
Vitamin E increased pneumonia risk by 68% among men who had the highest exposure to smoking and who did not exercise (22% of the ATBC participants), while vitamin E actually decreased pneumonia risk by 69% among participants who had the least exposure to smoking and who exercised during their leisure time (7·6% of the ATBC participants). The author claims that these findings refute there being a uniform effect of vitamin E supplementation on the risk of pneumonia.
•••••
Given the current limited understanding about who might benefit, Dr. Hemilä recommends that vitamin E should not be suggested for the general population for improving the immune system. The author concludes that there is a need for further research on vitamin E for non-smoking elderly men who exercise in their leisure time.
Showing posts with label counter-intuitive. Show all posts
Showing posts with label counter-intuitive. Show all posts
Wednesday, October 26, 2016
Monday, June 01, 2015
People more likely to cheat as they become more economically dependent on their spouses
http://www.eurekalert.org/pub_releases/2015-06/asa-pml052715.php
Public Release: 1-Jun-2015
American Sociological Association
Both men and women are more likely to cheat on their spouses the more economically dependent they are on them, according to a new study.
"You would think that people would not want to 'bite the hand that feeds them' so to speak, but that is not what my research shows," said study author Christin L. Munsch, an assistant professor of sociology at the University of Connecticut. "Instead, the findings indicate people like feeling relatively equal in their relationships. People don't like to feel dependent on another person."
According to Munsch, in an average year, there is about a 5 percent chance that women who are completely economically dependent on their husbands will cheat, whereas there is about a 15 percent chance that men who are entirely economically dependent on their wives will have an affair.
•••••
While Munsch found similarities in the way that men and women respond to being economically dependent, she discovered that men and women who are primary breadwinners in their marriages behave very differently. For women, the more they "breadwin" -- that is, the larger their percentage of the combined marital income -- the less likely they are to cheat.
•••••
Among men, those who are completely economically dependent on their spouses are the most likely to cheat. As the money men make relative to their spouses increases, their odds of committing adultery decrease until their total contribution to the pooled income reaches 70 percent. Men are least likely to cheat when they bring home 70 percent of a couples' total income. After 70 percent, however, men become increasingly more likely to stray.
•••••
Public Release: 1-Jun-2015
American Sociological Association
Both men and women are more likely to cheat on their spouses the more economically dependent they are on them, according to a new study.
"You would think that people would not want to 'bite the hand that feeds them' so to speak, but that is not what my research shows," said study author Christin L. Munsch, an assistant professor of sociology at the University of Connecticut. "Instead, the findings indicate people like feeling relatively equal in their relationships. People don't like to feel dependent on another person."
According to Munsch, in an average year, there is about a 5 percent chance that women who are completely economically dependent on their husbands will cheat, whereas there is about a 15 percent chance that men who are entirely economically dependent on their wives will have an affair.
•••••
While Munsch found similarities in the way that men and women respond to being economically dependent, she discovered that men and women who are primary breadwinners in their marriages behave very differently. For women, the more they "breadwin" -- that is, the larger their percentage of the combined marital income -- the less likely they are to cheat.
•••••
Among men, those who are completely economically dependent on their spouses are the most likely to cheat. As the money men make relative to their spouses increases, their odds of committing adultery decrease until their total contribution to the pooled income reaches 70 percent. Men are least likely to cheat when they bring home 70 percent of a couples' total income. After 70 percent, however, men become increasingly more likely to stray.
•••••
Tuesday, August 14, 2012
Feedback can have a negative impact on performance
http://www.eurekalert.org/pub_releases/2012-08/qmuo-fch081412.php
Public release date: 14-Aug-2012
Contact: Bridget Dempsey
Queen Mary, University of London
Research shows not all feedback is good for you
People who give positive encouragement and constructive criticism could be wasting their breath according to the latest research from a psychology expert at Queen Mary, University of London.
The study, published in the journal Frontiers in Neuroscience, found that when people received either positive or negative feedback about their performance on complex decision-making tasks, it made their decision making worse.
Study author Dr Magda Osman explained: "The kind of task people had to perform was difficult and demanding. So, when people received positive or negative feedback, it overloaded them with too much information and distracted them from making a good decision.
"We found that people's performance got worse when they had to make sense of the feedback they were given while also performing the main task.
"The role of feedback is overemphasised. People typically think that any form of feedback should improve performance in many tasks, and the more frequently it is given the better performance will be.
"However what needs to be considered is how complex the task is in the first place, because this will determine how much feedback will actually interfere with rather than facilitate performance."
Public release date: 14-Aug-2012
Contact: Bridget Dempsey
Queen Mary, University of London
Research shows not all feedback is good for you
People who give positive encouragement and constructive criticism could be wasting their breath according to the latest research from a psychology expert at Queen Mary, University of London.
The study, published in the journal Frontiers in Neuroscience, found that when people received either positive or negative feedback about their performance on complex decision-making tasks, it made their decision making worse.
Study author Dr Magda Osman explained: "The kind of task people had to perform was difficult and demanding. So, when people received positive or negative feedback, it overloaded them with too much information and distracted them from making a good decision.
"We found that people's performance got worse when they had to make sense of the feedback they were given while also performing the main task.
"The role of feedback is overemphasised. People typically think that any form of feedback should improve performance in many tasks, and the more frequently it is given the better performance will be.
"However what needs to be considered is how complex the task is in the first place, because this will determine how much feedback will actually interfere with rather than facilitate performance."
Saturday, December 17, 2011
Less Knowledge, More Power: Uninformed Can Be Vital to Democracy, Study Finds
Interesting and thought-provoking.
http://www.sciencedaily.com/releases/2011/12/111215141621.htm
ScienceDaily (Dec. 15, 2011) — Contrary to the ideal of a completely engaged electorate, individuals who have the least interest in a specific outcome can actually be vital to achieving a democratic consensus. These individuals dilute the influence of powerful minority factions who would otherwise dominate everyone else, according to new research published in the journal Science.
[...]
"We show that when the uninformed participate, the group can come to a majority decision even in the face of a powerful minority," Couzin said. "They prevent deadlock and fragmentation because the strength of an opinion no longer matters -- it comes down to numbers. You can imagine this being a good or bad thing. Either way, a certain number of uninformed individuals keep that minority from dictating or complicating the behavior of the group."
Of course this effect has its limits, Couzin said. He and his co-authors also found that if the number of uninformed becomes too high, a group ceases to function coherently, with neither the majority nor the minority taking the lead. "Eventually, noise dominates because there just aren't enough informed individuals to guide the group," he said.
[...]
..
Tuesday, May 05, 2009
Quack remedies spread by virtue of being useless
http://www.newscientist.com/article/dn17064-quack-remedies-spread-by-virtue-of-being-useless.html
12:32 01 May 2009 by Ewen Callaway
Eating a vulture won't clear a bad case of syphilis nor will a drink made of rotting snakes treat leprosy, but these and other bogus medical treatments spread precisely because they don't work. That's the counterintuitive finding of a mathematical model of medical quackery.
Ineffective treatments don't cure an illness, so sufferers demonstrate them to more people than those who recovery quickly after taking real medicines.
"The assumption is that when people pick up treatments to try, they're basically observing other people," says Mark Tanaka, a mathematical biologist at the University of New South Wales in Sydney, who led the study. "People don't necessarily know that what somebody is trying is going to work."
The World Health Organization is demanding better proof that folk medicines work before they can be approved. And the Malaysian government has rejected more than a third of the 25,000 applications to register traditional medicines it has received because the treatments are ineffective or dangerous.
Despite these efforts, quack medicine persists around the world. Some Nigerians treat malaria with witchcraft, a South African health minister recently claimed that garlic and beetroot treat HIV, and western health stores brim with unproven treatments for almost any disease imaginable. For instance St John's wort does nothing for attention deficit hyperactive disorder in children, a recent placebo-controlled trial concluded.
To understand why these quack medical treatments persist in the face of better proven remedies, Tanaka applied mathematical models used to measure evolutionary fitness to medical treatments.
His model accounted for factors including the rate of conversion to a treatment, the effectiveness of a treatment, the rate at which people abandon a treatment, the odds of recovering naturally, and the chances of dying. The model starts with a single person demonstrating a treatment – rubbish or not – and measures how many people are influenced to go on to give the treatment a try.
Under a wide range of conditions, quack treatments garnered more converts than proven hypothetical medicines that offer quicker recovery, Tanaka found. "The very fact that they don't work mean that people that use them stay sick longer" and demonstrate a treatment to more people, he says.
Bad treatments don't always win out. Recurring diseases are more likely to promote effective treatments than rare diseases because repeated demonstration weeds out bad treatments, Tanaka found.
But is this model valid in cultures where evidence-based medicine predominates, and government groups such as the US Food and Drug Administration vet most medical treatments?
Tanaka thinks so, pointing to the popularity of alternative medicines and the debate over the effectiveness of FDA-approved drugs. "In many situations people will just observe and copy anyway, regardless what the official information is," he says.
And in some cases, one peer-reviewed study may conclude that a drug works, while another shows it doesn't. "Even where there is a bit of clinical research, we don't really know yet whether at lot of medicines are effective," he says.
"I think it's an interesting idea. It's quite clever", James Holland Jones, a biological anthropologist at Stanford University in California, says of the model. However, language allows people to vet unproven remedies without trying them, he adds – that is, you can just ask if a treatment was effective. "You don't necessarily have to copy everything."
====================================================
12:32 01 May 2009 by Ewen Callaway
Eating a vulture won't clear a bad case of syphilis nor will a drink made of rotting snakes treat leprosy, but these and other bogus medical treatments spread precisely because they don't work. That's the counterintuitive finding of a mathematical model of medical quackery.
Ineffective treatments don't cure an illness, so sufferers demonstrate them to more people than those who recovery quickly after taking real medicines.
"The assumption is that when people pick up treatments to try, they're basically observing other people," says Mark Tanaka, a mathematical biologist at the University of New South Wales in Sydney, who led the study. "People don't necessarily know that what somebody is trying is going to work."
The World Health Organization is demanding better proof that folk medicines work before they can be approved. And the Malaysian government has rejected more than a third of the 25,000 applications to register traditional medicines it has received because the treatments are ineffective or dangerous.
Despite these efforts, quack medicine persists around the world. Some Nigerians treat malaria with witchcraft, a South African health minister recently claimed that garlic and beetroot treat HIV, and western health stores brim with unproven treatments for almost any disease imaginable. For instance St John's wort does nothing for attention deficit hyperactive disorder in children, a recent placebo-controlled trial concluded.
To understand why these quack medical treatments persist in the face of better proven remedies, Tanaka applied mathematical models used to measure evolutionary fitness to medical treatments.
His model accounted for factors including the rate of conversion to a treatment, the effectiveness of a treatment, the rate at which people abandon a treatment, the odds of recovering naturally, and the chances of dying. The model starts with a single person demonstrating a treatment – rubbish or not – and measures how many people are influenced to go on to give the treatment a try.
Under a wide range of conditions, quack treatments garnered more converts than proven hypothetical medicines that offer quicker recovery, Tanaka found. "The very fact that they don't work mean that people that use them stay sick longer" and demonstrate a treatment to more people, he says.
Bad treatments don't always win out. Recurring diseases are more likely to promote effective treatments than rare diseases because repeated demonstration weeds out bad treatments, Tanaka found.
But is this model valid in cultures where evidence-based medicine predominates, and government groups such as the US Food and Drug Administration vet most medical treatments?
Tanaka thinks so, pointing to the popularity of alternative medicines and the debate over the effectiveness of FDA-approved drugs. "In many situations people will just observe and copy anyway, regardless what the official information is," he says.
And in some cases, one peer-reviewed study may conclude that a drug works, while another shows it doesn't. "Even where there is a bit of clinical research, we don't really know yet whether at lot of medicines are effective," he says.
"I think it's an interesting idea. It's quite clever", James Holland Jones, a biological anthropologist at Stanford University in California, says of the model. However, language allows people to vet unproven remedies without trying them, he adds – that is, you can just ask if a treatment was effective. "You don't necessarily have to copy everything."
====================================================
I would expect that this effect would be augmented by the placebo effect.
Saturday, April 25, 2009
Lice can be nice to us
http://communications.nottingham.ac.uk/News/Article/Lice-can-be-nice-to-us.html
Wed, 22 Apr 2009 16:29:00 GMT
Parasite infestations might have a good side. Wild mice from a Nottinghamshire forest have given experts at The University of Nottingham clues as to the importance of some parasites, such as lice, for the conditioning of a “natural” immune system.
Jan Bradley, Professor of Parasitology, said: “Our understanding of mammalian immunology is largely based on rodents reared under highly unnatural pathogen and stress-free conditions. Analysing the immune response in wild populations can give crucial insights into how the immune system functions in its natural context.”
Many health problems in modern humans are caused by over-active immune responses. The immune system should be able to tell the difference between foreign invaders and its own body cells. But sometimes it can mistake self proteins for non self proteins triggering an attack on its own body and causing an autoimmune disease such as arthritis, asthma, diabetes or multiple sclerosis. Or the body can mistake a harmless substance as a threat causing an allergic response.
The authors say some parasites may exert a moderating effect on the function of a key component of the immune system, which could help reduce overall immune reactivity and the risk of developing immune dysfunctions.
Their research, published in the open access journal BMC Biology, links the louse Polyplax serrata to a strong dampening of certain immune responses in wild wood mice. This implies that other mammals, such as modern humans, that develop in artificial environments may have less regulated, overactive immune systems precisely because they are not exposed to parasites throughout their lives.
The researchers speculate that the louse is able to exert some kind of immuno-suppressive effect, possibly directly by secreting some substance into the mice from its saliva, or indirectly by transmitting bacteria or other pathogens.
Professor Bradley said: “Much like laboratory mice, people in developed countries are currently exposed to a very different profile of infections to that encountered by their ancestors. It is possible that the immune dysfunctions we see today are the result of immune systems moulded by evolution for a set of challenges completely different to those encountered in modern times.”
Wed, 22 Apr 2009 16:29:00 GMT
Parasite infestations might have a good side. Wild mice from a Nottinghamshire forest have given experts at The University of Nottingham clues as to the importance of some parasites, such as lice, for the conditioning of a “natural” immune system.
Jan Bradley, Professor of Parasitology, said: “Our understanding of mammalian immunology is largely based on rodents reared under highly unnatural pathogen and stress-free conditions. Analysing the immune response in wild populations can give crucial insights into how the immune system functions in its natural context.”
Many health problems in modern humans are caused by over-active immune responses. The immune system should be able to tell the difference between foreign invaders and its own body cells. But sometimes it can mistake self proteins for non self proteins triggering an attack on its own body and causing an autoimmune disease such as arthritis, asthma, diabetes or multiple sclerosis. Or the body can mistake a harmless substance as a threat causing an allergic response.
The authors say some parasites may exert a moderating effect on the function of a key component of the immune system, which could help reduce overall immune reactivity and the risk of developing immune dysfunctions.
Their research, published in the open access journal BMC Biology, links the louse Polyplax serrata to a strong dampening of certain immune responses in wild wood mice. This implies that other mammals, such as modern humans, that develop in artificial environments may have less regulated, overactive immune systems precisely because they are not exposed to parasites throughout their lives.
The researchers speculate that the louse is able to exert some kind of immuno-suppressive effect, possibly directly by secreting some substance into the mice from its saliva, or indirectly by transmitting bacteria or other pathogens.
Professor Bradley said: “Much like laboratory mice, people in developed countries are currently exposed to a very different profile of infections to that encountered by their ancestors. It is possible that the immune dysfunctions we see today are the result of immune systems moulded by evolution for a set of challenges completely different to those encountered in modern times.”
Wednesday, April 15, 2009
Energy Drinks Work -- In Mysterious Ways
http://www.sciencedaily.com/releases/2009/04/090415075142.htm
ScienceDaily (Apr. 15, 2009) — Runners clutching bottles of energy drink are a common sight, and it has long been known that sugary drinks and sweets can significantly improve athletes' performance in endurance events. The question is how?
Clearly, 'sports' drinks and tablets contain calories. But this alone is not enough to explain the boost, and the benefits are felt even if the drink is spat out rather than swallowed. Nor does the sugary taste solve the riddle, as artificial sweeteners do not boost performance even when they are indistinguishable from real sugars.
Writing in the latest issue of The Journal of Physiology, Ed Chambers and colleagues not only show that sugary drinks can significantly boost performance in an endurance event without being ingested, but so can a tasteless carbohydrate – and they do so in unexpected ways.
The researchers prepared drinks that contained either glucose (a sugar), maltodextrin (a tasteless carbohydrate) or neither, then carefully laced them with artificial sweeteners until they tasted identical. They asked endurance-trained athletes to complete a challenging time-trial, during which they rinsed their mouths with one of the three concoctions.
The results were striking. Athletes given the glucose or maltodextrin drinks outperformed those on 'disguised' water by 2 - 3% and sustained a higher average power output and pulse rate, even though didn't feel they were working any harder. The authors conclude that as-yet unidentified receptors in the mouth independent from the usual 'sweet' taste buds must be responsible. "Much of the benefit from carbohydrate in sports drinks is provided by signalling directly from mouth to brain rather than providing energy for the working muscles," explained Dr Chambers.
The team then used a neuro-imaging technique known as fMRI to monitor the athletes' brain activity shortly after giving them one of the three compounds. They found that both glucose and maltodextrin triggered specific areas of the brain associated with reward or pleasure, while the artificial sweetener did not. This acts to reduce the athletes' perception of their workload, suggest the authors, and hence enables them to sustain a higher average output.
Their findings support the emerging 'central governor hypothesis' – the theory that it is not the muscles, heart or lungs that ultimately limit performance, but the brain itself, based on the information it receives from the body. Stimulating the brain in certain ways – such as swilling sugary drinks – can boost output, perhaps giving athletes that all-important edge over their rivals.
ScienceDaily (Apr. 15, 2009) — Runners clutching bottles of energy drink are a common sight, and it has long been known that sugary drinks and sweets can significantly improve athletes' performance in endurance events. The question is how?
Clearly, 'sports' drinks and tablets contain calories. But this alone is not enough to explain the boost, and the benefits are felt even if the drink is spat out rather than swallowed. Nor does the sugary taste solve the riddle, as artificial sweeteners do not boost performance even when they are indistinguishable from real sugars.
Writing in the latest issue of The Journal of Physiology, Ed Chambers and colleagues not only show that sugary drinks can significantly boost performance in an endurance event without being ingested, but so can a tasteless carbohydrate – and they do so in unexpected ways.
The researchers prepared drinks that contained either glucose (a sugar), maltodextrin (a tasteless carbohydrate) or neither, then carefully laced them with artificial sweeteners until they tasted identical. They asked endurance-trained athletes to complete a challenging time-trial, during which they rinsed their mouths with one of the three concoctions.
The results were striking. Athletes given the glucose or maltodextrin drinks outperformed those on 'disguised' water by 2 - 3% and sustained a higher average power output and pulse rate, even though didn't feel they were working any harder. The authors conclude that as-yet unidentified receptors in the mouth independent from the usual 'sweet' taste buds must be responsible. "Much of the benefit from carbohydrate in sports drinks is provided by signalling directly from mouth to brain rather than providing energy for the working muscles," explained Dr Chambers.
The team then used a neuro-imaging technique known as fMRI to monitor the athletes' brain activity shortly after giving them one of the three compounds. They found that both glucose and maltodextrin triggered specific areas of the brain associated with reward or pleasure, while the artificial sweetener did not. This acts to reduce the athletes' perception of their workload, suggest the authors, and hence enables them to sustain a higher average output.
Their findings support the emerging 'central governor hypothesis' – the theory that it is not the muscles, heart or lungs that ultimately limit performance, but the brain itself, based on the information it receives from the body. Stimulating the brain in certain ways – such as swilling sugary drinks – can boost output, perhaps giving athletes that all-important edge over their rivals.
Saturday, April 11, 2009
Appendix Isn't Useless at All: It's a Safe House for Good Bacteria
http://www.dukehealth.org/HealthLibrary/News/10151
By Duke Medicine News and Communications
DURHAM, N.C. – Long denigrated as vestigial or useless, the appendix now appears to have a reason to be – as a "safe house" for the beneficial bacteria living in the human gut.
Drawing upon a series of observations and experiments, Duke University Medical Center investigators postulate that the beneficial bacteria in the appendix that aid digestion can ride out a bout of diarrhea that completely evacuates the intestines and emerge afterwards to repopulate the gut. Their theory appears online in the Journal of Theoretical Biology.
"While there is no smoking gun, the abundance of circumstantial evidence makes a strong case for the role of the appendix as a place where the good bacteria can live safe and undisturbed until they are needed," said William Parker, Ph.D., assistant professor of experimental surgery, who conducted the analysis in collaboration with R. Randal Bollinger, M.D., Ph.D., Duke professor emeritus in general surgery.
The appendix is a slender two- to four-inch pouch located near the juncture of the large and small intestines. While its exact function in humans has been debated by physicians, it is known that there is immune system tissue in the appendix.
The gut is populated with different microbes that help the digestive system break down the foods we eat. In return, the gut provides nourishment and safety to the bacteria. Parker now believes that the immune system cells found in the appendix are there to protect, rather than harm, the good bacteria.
For the past ten years, Parker has been studying the interplay of these bacteria in the bowels, and in the process has documented the existence in the bowel of what is known as a biofilm. This thin and delicate layer is an amalgamation of microbes, mucous and immune system molecules living together atop of the lining the intestines.
"Our studies have indicated that the immune system protects and nourishes the colonies of microbes living in the biofilm," Parkers explained. "By protecting these good microbes, the harmful microbes have no place to locate. We have also shown that biofilms are most pronounced in the appendix and their prevalence decreases moving away from it."
This new function of the appendix might be envisioned if conditions in the absence of modern health care and sanitation are considered, Parker said.
"Diseases causing severe diarrhea are endemic in countries without modern health and sanitation practices, which often results in the entire contents of the bowels, including the biofilms, being flushed from the body," Parker said. He added that the appendix's location and position is such that it is expected to be relatively difficult for anything to enter it as the contents of the bowels are emptied.
"Once the bowel contents have left the body, the good bacteria hidden away in the appendix can emerge and repopulate the lining of the intestine before more harmful bacteria can take up residence," Parker continued. "In industrialized societies with modern medical care and sanitation practices, the maintenance of a reserve of beneficial bacteria may not be necessary. This is consistent with the observation that removing the appendix in modern societies has no discernable negative effects."
Several decades ago, scientists suggested that people in industrialized societies might have such a high rate of appendicitis because of the so-called "hygiene hypothesis," Parker said. This hypothesis posits that people in "hygienic" societies have higher rates of allergy and perhaps autoimmune disease because they -- and hence their immune systems -- have not been as challenged during everyday life by the host of parasites or other disease-causing organisms commonly found in the environment. So when these immune systems are challenged, they can over-react.
"This over-reactive immune system may lead to the inflammation associated with appendicitis and could lead to the obstruction of the intestines that causes acute appendicitis," Parker said. "Thus, our modern health care and sanitation practices may account not only for the lack of a need for an appendix in our society, but also for much of the problems caused by the appendix in our society."
Parker conducted a deductive study because direct examination the appendix's function would be difficult. Other than humans, the only mammals known to have appendices are rabbits, opossums and wombats, and their appendices are markedly different than the human appendix.
Parker's overall research into the existence and function of biofilms is supported by the National Institutes of Health. Other Duke members of the team were Andrew Barbas, Errol Bush, and Shu Lin.
By Duke Medicine News and Communications
DURHAM, N.C. – Long denigrated as vestigial or useless, the appendix now appears to have a reason to be – as a "safe house" for the beneficial bacteria living in the human gut.
Drawing upon a series of observations and experiments, Duke University Medical Center investigators postulate that the beneficial bacteria in the appendix that aid digestion can ride out a bout of diarrhea that completely evacuates the intestines and emerge afterwards to repopulate the gut. Their theory appears online in the Journal of Theoretical Biology.
"While there is no smoking gun, the abundance of circumstantial evidence makes a strong case for the role of the appendix as a place where the good bacteria can live safe and undisturbed until they are needed," said William Parker, Ph.D., assistant professor of experimental surgery, who conducted the analysis in collaboration with R. Randal Bollinger, M.D., Ph.D., Duke professor emeritus in general surgery.
The appendix is a slender two- to four-inch pouch located near the juncture of the large and small intestines. While its exact function in humans has been debated by physicians, it is known that there is immune system tissue in the appendix.
The gut is populated with different microbes that help the digestive system break down the foods we eat. In return, the gut provides nourishment and safety to the bacteria. Parker now believes that the immune system cells found in the appendix are there to protect, rather than harm, the good bacteria.
For the past ten years, Parker has been studying the interplay of these bacteria in the bowels, and in the process has documented the existence in the bowel of what is known as a biofilm. This thin and delicate layer is an amalgamation of microbes, mucous and immune system molecules living together atop of the lining the intestines.
"Our studies have indicated that the immune system protects and nourishes the colonies of microbes living in the biofilm," Parkers explained. "By protecting these good microbes, the harmful microbes have no place to locate. We have also shown that biofilms are most pronounced in the appendix and their prevalence decreases moving away from it."
This new function of the appendix might be envisioned if conditions in the absence of modern health care and sanitation are considered, Parker said.
"Diseases causing severe diarrhea are endemic in countries without modern health and sanitation practices, which often results in the entire contents of the bowels, including the biofilms, being flushed from the body," Parker said. He added that the appendix's location and position is such that it is expected to be relatively difficult for anything to enter it as the contents of the bowels are emptied.
"Once the bowel contents have left the body, the good bacteria hidden away in the appendix can emerge and repopulate the lining of the intestine before more harmful bacteria can take up residence," Parker continued. "In industrialized societies with modern medical care and sanitation practices, the maintenance of a reserve of beneficial bacteria may not be necessary. This is consistent with the observation that removing the appendix in modern societies has no discernable negative effects."
Several decades ago, scientists suggested that people in industrialized societies might have such a high rate of appendicitis because of the so-called "hygiene hypothesis," Parker said. This hypothesis posits that people in "hygienic" societies have higher rates of allergy and perhaps autoimmune disease because they -- and hence their immune systems -- have not been as challenged during everyday life by the host of parasites or other disease-causing organisms commonly found in the environment. So when these immune systems are challenged, they can over-react.
"This over-reactive immune system may lead to the inflammation associated with appendicitis and could lead to the obstruction of the intestines that causes acute appendicitis," Parker said. "Thus, our modern health care and sanitation practices may account not only for the lack of a need for an appendix in our society, but also for much of the problems caused by the appendix in our society."
Parker conducted a deductive study because direct examination the appendix's function would be difficult. Other than humans, the only mammals known to have appendices are rabbits, opossums and wombats, and their appendices are markedly different than the human appendix.
Parker's overall research into the existence and function of biofilms is supported by the National Institutes of Health. Other Duke members of the team were Andrew Barbas, Errol Bush, and Shu Lin.
Tuesday, March 24, 2009
Religious Patients More Likely to Seek End-of-Life Cancer Care
Interesting. A major attraction of religion is that it claims to offer life after death that is better than life on earth. So one might expect believers to be less afraid of death. However, my personal experience with a few friends and family when they were dying does not show this to be the case. Eg., my grandmother, who was quite religious, wondered if Got was punishing her for something by giving her cancer. It just added to her distress.
http://www.bloomberg.com/apps/news?pid=20601124&sid=awTGSVgCTfCY&refer=science
By Elizabeth Lopatto
March 17 (Bloomberg) -- Patients who used religious faith to cope with their advanced cancer were three times more likely to receive intensive life-prolonging treatment than those not relying on spiritual beliefs, according to a Harvard University study.
The faith-oriented patients were more likely to use ventilation to breathe or have CPR administered in the week before they died, according to the study, published today in the Journal of the American Medical Association. They wanted physicians to take “heroic measures” to keep them alive, and were less likely to have do-not-resuscitate orders, living wills or someone designated as their health-care proxy.
It isn’t clear why these patients pursue more aggressive treatment, said Andrea Phelps, a senior medical resident at Beth Israel Deaconess Medical Center in Boston and the study’s lead author. It may be that people with a strong sense of faith are more optimistic or are more satisfied with their quality of life, Phelps said. Doctors should be sensitive to religious beliefs and help plan care accordingly, Phelps said.
Saturday, February 07, 2009
Green Tea Blocks Benefits Of Cancer Drug
Note that green tea might be effective in reducing the probability of getting cancer to start out, with w/o contradicting this study.
http://www.sciencedaily.com/releases/2009/02/090203162355.htm
ScienceDaily (Feb. 5, 2009) — Contrary to popular assumptions about the health benefits of green tea, researchers at the University of Southern California (USC) have found that the widely used supplement renders a cancer drug used to treat multiple myeloma and mantle cell lymphoma completely ineffective in treating cancer.
The study, which found that a component of green tea extract (GTE) called EGCG destroys any anticancer activity of the drug Velcade in tumor-bearing mice, will be published in the journal Blood.
"Our finding that GTE or EGCG blocked the therapeutic action of Velcade was completely unexpected," says lead author Axel H. Schönthal, PhD, associate professor in the Department of Microbiology and Immunology at the Keck School of Medicine of USC. "Our hypothesis was that GTE or EGCG would enhance the anti-tumor effects of Velcade, and that a combination of GTE with Velcade (or EGCG with Velcade) would turn out to be a superior cancer treatment as compared to treatment with Velcade alone."
...
Schönthal points out that for patients on Velcade, supplementing with green tea products should reduce the burden of harsh side effects—which might be attractive to the patient, but comes at a high cost.
"Essentially, in addition to not being able to attack tumor cells, Velcade would be unable to cause side effects either," he says. "As a result, the patient would feel a lot better and conclude that the consumption of GTE helped cope with side effects—while in reality, Velcade simply wasn't active in the first place."
Wednesday, December 03, 2008
Tuesday, November 25, 2008
Overuse Of Narcotics And Barbiturates May Make Migraine Attacks More Frequent
Not that surprising, since we've know for years about rebound headaches caused by over-use of aspirin and related pain relievers.
http://www.sciencedaily.com/releases/2008/11/081119092941.htm
ScienceDaily (Nov. 25, 2008) — A team of researchers led by investigators at the Albert Einstein College of Medicine of Yeshiva University has determined that certain commonly-prescribed medications may have the unintended consequence of increasing the frequency of migraine attacks. This important finding could alter the way doctors prescribe migraine medicines.
In a recent article published in the journal Headache, the Einstein-led study of more than 8,000 migraine sufferers nationwide, found that the use of medications containing barbiturates or narcotics — which relieve migraine short-term — may make migraine worse if these medications are overused. Treatment with these classes of medicines was associated with an increased risk of transformed migraine (TM) headaches, a form of migraine characterized by 15 or more days of headache per month.
The finding is significant because 35 million Americans suffer from migraine headaches and an additional 5 million suffer from transformed migraine. Migraine symptoms include throbbing head pain, most commonly on one side. The pain can worsen with physical activity. Attacks most commonly last from 4 to 72 hours, but may persist for longer. More severe attacks are overwhelming and hinder daily activities. In addition to personal suffering, lost labor costs in the U.S. due to migraine are in excess of $13 billion per year according to an earlier study from the Einstein team.
http://www.sciencedaily.com/releases/2008/11/081119092941.htm
ScienceDaily (Nov. 25, 2008) — A team of researchers led by investigators at the Albert Einstein College of Medicine of Yeshiva University has determined that certain commonly-prescribed medications may have the unintended consequence of increasing the frequency of migraine attacks. This important finding could alter the way doctors prescribe migraine medicines.
In a recent article published in the journal Headache, the Einstein-led study of more than 8,000 migraine sufferers nationwide, found that the use of medications containing barbiturates or narcotics — which relieve migraine short-term — may make migraine worse if these medications are overused. Treatment with these classes of medicines was associated with an increased risk of transformed migraine (TM) headaches, a form of migraine characterized by 15 or more days of headache per month.
The finding is significant because 35 million Americans suffer from migraine headaches and an additional 5 million suffer from transformed migraine. Migraine symptoms include throbbing head pain, most commonly on one side. The pain can worsen with physical activity. Attacks most commonly last from 4 to 72 hours, but may persist for longer. More severe attacks are overwhelming and hinder daily activities. In addition to personal suffering, lost labor costs in the U.S. due to migraine are in excess of $13 billion per year according to an earlier study from the Einstein team.
Tuesday, September 16, 2008
Prenatal stress may form a component of the inherent desire for physical activity.
With all the negative effects on a child from pre-natal stress, maybe this is a good effect.
http://www.eurekalert.org/pub_releases/2008-09/plos-rsc091508.php
Public release date: 16-Sep-2008
Contact: Jamie Hanlon
Public Library of Science
Research supports correlation between finger lengths and stress hormones
Edmonton—If you find yourself lacking in motivation to go for a run or hit the gym, you may want to check your fingers. According to a joint University of Alberta/ University of California- Riverside research study to be published by PLoS ONE, the online, open-access journal from the Public Library of Science, there is a direct correlation between digit length and voluntary exercise.
The study also casts some doubt on a previously released study which linked digit length and male aggression.
While both situations were first thought to have been caused by exposure to elevated levels of prenatal testosterone in the womb, research conducted using lab mice yielded no concrete evidence to support that original hypothesis. The new study, conducted using 1,000 white mice, seems to support a stronger connection between digit length, voluntary exercise and high levels of prenatal stress hormones, which was indicated by the difference in activity level between the control mice and the selectively-bred active mice. Given the results, the findings suggest that prenatal stress rather than prenatal testosterone levels in the womb, forms a component of the inherent desire for physical activity.
"The research shows a link, or relationship, between the brain, behaviour and personality traits and the shape of the hand," said Peter Hurd, University of Alberta psychology professor and one of the lead researchers. "It opens the door to the notion that aspects of one's personality, in this case the desire to exercise, are fixed very early in life."
###
Peter Hurd
University of Alberta
Citation: Yan RHY, Malisch JL, Hannon RM, Hurd PL, Garland T Jr. (2008) Selective Breeding for a Behavioral Trait Changes Digit Ratio. PLoS ONE 3(9): e3216. doi:10.1371/journal.pone.0003216
PLEASE ADD THE LINK TO THE PUBLISHED ARTICLE IN ONLINE VERSIONS OF YOUR REPORT (URL live from Sep 17): http://dx.plos.org/10.1371/journal.pone.0003216
Friday, September 05, 2008
Intellectual work induces excessive calorie intake
I can really believe this. I get much hungrier when I'm working at an IT job, even though I'm just sitting down most of the day, than when I'm at home or working at a more physical job. Years ago, I read of a study that said mental work causes a person to require more sleep than physical work. Since a major function of sleep appears to be processing experiences we had while we were awake, this makes sense.http://www.eurekalert.org/pub_releases/2008-09/ul-iwi090408.php
Quebec City, September 4, 2008—A Université Laval research team has demonstrated that intellectual work induces a substantial increase in calorie intake. The details of this discovery, which could go some way to explaining the current obesity epidemic, are published in the most recent issue of Psychosomatic Medicine.
The research team, supervised by Dr. Angelo Tremblay, measured the spontaneous food intake of 14 students after each of three tasks: relaxing in a sitting position, reading and summarizing a text, and completing a series of memory, attention, and vigilance tests on the computer. After 45 minutes at each activity, participants were invited to eat as much as they wanted from a buffet.
The researchers had already shown that each session of intellectual work requires only three calories more than the rest period. However, despite the low energy cost of mental work, the students spontaneously consumed 203 more calories after summarizing a text and 253 more calories after the computer tests. This represents a 23.6% and 29.4 % increase, respectively, compared with the rest period.
Blood samples taken before, during, and after each session revealed that intellectual work causes much bigger fluctuations in glucose and insulin levels than rest periods. "These fluctuations may be caused by the stress of intellectual work, or also reflect a biological adaptation during glucose combustion," hypothesized Jean-Philippe Chaput, the study's main author. The body could be reacting to these fluctuations by spurring food intake in order to restore its glucose balance, the only fuel used by the brain.
"Caloric overcompensation following intellectual work, combined with the fact that we are less physically active when doing intellectual tasks, could contribute to the obesity epidemic currently observed in industrialized countries," said Mr. Chaput. "This is a factor that should not be ignored, considering that more and more people hold jobs of an intellectual nature," the researcher concluded.
Wednesday, July 30, 2008
Hey Fever! The Surprise Benefit Of Allergies
There have already been indications that people with strong allergic responses might be more resistant to parasites, and that the paucity of parasites in modern life causes an increase in allergies. This is because the part of the immune system that would otherwise be occupied fighting parasites doesn't have enough real threats to keep it occupied, and so "fights" normally harmless allergens.
http://www.sciencedaily.com/releases/2008/07/080729133643.htm
ScienceDaily (July 30, 2008) — Long-suffering victims of allergies such as asthma and hay fever might enjoy a surprise benefit, according to research led by the University of New South Wales (UNSW).
In a paper presented at an international symposium in Sydney, the researchers show that people with one of these atopic diseases are up to 25 percent less likely to get the most common type of Non-Hodgkin Lymphoma (NHL).
...The more atopic diseases the individual has, the less likely they are to succumb to NHL. If an individual has three of these conditions, they are 40 percent less likely to get NHL.
Having had asthma and hay fever for a long time, also appears to be of greater benefit.
The result is significant given that the incidence of NHL in developed countries has escalated dramatically in the past 50 years. It is three times more prevalent now than it was in 1950, making it the sixth most common cause of cancer death in Australia, yet the cause of most cases remains unknown.
"This was a surprise result," said the lead author, Dr Claire Vajdic. "The only known strong risk factors for NHL are immune deficiency and certain infections. This occurs in people with uncontrolled HIV infection, and those who have had a solid organ transplant.
"So we thought other forms of immune dysregulation such as atopic diseases – including hayfever, asthma and food allergies – might relate to the development of lymphoma. It was therefore intuitive to think that these conditions would increase the risk, but in fact, they do the reverse," she said.
The research found that risk was reduced in B-cell NHL only. This is the most common type of NHL.
"While the relevant biological mechanisms are not yet known, the pooled data indicate that chronic and multiple atopic conditions impart the greatest reduction in risk," said Dr Vajdic. "Investigation of the genetic and environmental factors underlying atopy and the apparent inverse effect of atopy on NHL risk will inform our understanding of the complex biological pathways that may be involved."
Tuesday, June 10, 2008
ADHD an advantage for nomadic tribesmen?
http://www.eurekalert.org/pub_releases/2008-06/bc-aaa060608.php
A propensity for attention deficit hyperactivity disorder (ADHD) might be beneficial to a group of Kenyan nomads, according to new research published in the open access journal BMC Evolutionary Biology. Scientists have shown that an ADHD-associated version of the gene DRD4 is associated with better health in nomadic tribesmen, and yet may cause malnourishment in their settled cousins.
A propensity for attention deficit hyperactivity disorder (ADHD) might be beneficial to a group of Kenyan nomads, according to new research published in the open access journal BMC Evolutionary Biology. Scientists have shown that an ADHD-associated version of the gene DRD4 is associated with better health in nomadic tribesmen, and yet may cause malnourishment in their settled cousins.
Monday, April 28, 2008
Friendly Germs
http://www.sciencedaily.com/releases/2008/04/080428084232.htm
ScienceDaily (Apr. 28, 2008) — Children who attend day care or play groups have about a 30% lower risk of developing the most common type of childhood leukaemia than those who do not, according to a new analysis of studies investigating the link.
ScienceDaily (Apr. 28, 2008) — Children who attend day care or play groups have about a 30% lower risk of developing the most common type of childhood leukaemia than those who do not, according to a new analysis of studies investigating the link.
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