Researchers hope to make mosquito 'flying vaccinator': AFP

TOKYO — Japanese researchers hope one day to turn blood-sucking mosquitoes into deliverers of vaccines that could instead inoculate millions for free.
A new study shows real promise for turning the reviled insects into heroes by genetically modifying them to make them "flying vaccinators", according to scientists at Jichi Medical University north of Tokyo.
The researchers have already genetically modified a mosquito species so that its saliva contains a protein that acts as a vaccine against leishmaniasis, a sandfly-borne disease that triggers terrible skin sores and can be fatal.
The team confirmed that mice bitten by the transgenic mosquito developed an antibody to the disease, meaning they had built up immunity, said Shigeto Yoshida, the associate professor who has led the research.
Similarly the mosquitoes could be used to help combat malaria, perhaps a decade from now, said the malaria expert.
"What's good is that they don't charge you for vaccinations," Yoshida told AFP by telephone on Wednesday.
"You would be vaccinated without even noticing. You wouldn't need any drug and you wouldn't need to show up at a designated place for mass vaccinations."
Repeat bites would only strengthen the immunity, he said.
For now a problem is that no effective vaccine exists, because malaria's antigen, which triggers immune reactions, changes frequently.
However, Yoshida expects science will come up with a solution, and that the transgenic mosquito will ultimately help rid the developing world of a deadly scourge.
Nearly one million people die each year from malaria -- most of them children -- predominantly in Africa and Asia, according to the World Health Organization.
There are several anti-malarial drugs, none of them universally effective, and a treatment, called artemisinin.
"The treatment works but it is beyond the reach of people who need to worry about food for tomorrow. They just can't afford it," Yoshida said. "Malaria is a disease closely linked to poverty. A flying vaccinator matters a lot."
Yoshida conceded the new approach could raise ethical questions about carrying out vaccinations without informed consent.
"Technically speaking I believe it's a matter of 10 years or so, but it's a different issue whether society would accept it," he said.
Another problem is that the vaccinator mosquito may still pick up and spread the infected blood of a malaria-positive person.
Yoshida's team is hoping it can tackle this problem, by also developing a mosquito that kills malaria parasites inside its own body. AFP

Chemical in Bananas Identified as Potent Inhibitor of HIV Infection

ScienceDaily (Mar. 16, 2010) — A potent new inhibitor of HIV, derived from bananas, may open the door to new treatments to prevent sexual transmission of HIV, according to a newly published University of Michigan Medical School study.

Scientists have an emerging interest in lectins, naturally occurring chemicals in plants, because of their ability to halt the chain of reaction that leads to a variety of infections.
In laboratory tests, BanLec, the lectin found in bananas, was as potent as two current anti-HIV drugs. Based on the findings published March 19 in the Journal of Biological Chemistry, BanLec may become a less expensive new component of applied vaginal microbicides, researchers say.
New ways of stopping the spread of the HIV are vitally needed. The rate of new infections of HIV is outpacing the rate of new individuals getting anti-retroviral drugs by 2.5 to1, and at present it appears an effective vaccine is years away.

"HIV is still rampant in the U.S. and the explosion in poorer countries continues to be a bad problem because of tremendous human suffering and the cost of treating it," says study senior author David Marvovitz, M.D., professor of internal medicine at the U-M Medical School.
Although condom use is quite effective, condoms are most successful in preventing infection if used consistently and correctly, which is often not the case.
"That's particularly true in developing countries where women have little control over sexual encounters so development of a long-lasting, self-applied microbicide is very attractive," Markovitz says.
Some of the most promising compounds for inhibiting vaginal and rectal HIV transmission are agents that block HIV prior to integration into its target cell.
The new research describes the complex actions of lectins and their ability to outsmart HIV. Lectins are sugar-binding proteins. They can identify foreign invaders, like a virus, and attach themselves to the pathogen.
The U-M team discovered BanLec, the lectin in bananas, can inhibit HIV infection by binding to the sugar-rich HIV-1 envelope protein, gp120, and blocking its entry to the body.
Co-authors Erwin J. Goldstein, Ph.D., professor emeritus of biological chemistry at U-M and Harry C. Winter, Ph.D., research assistant professor in biological chemistry at U-M, developed the biopurification method to isolate BanLec from bananas. Following their work, the U-M team discovered BanLec is an effective anti-HIV lectin and is similar in potency to T-20 and maraviroc, two anti-HIV drugs currently in clinical use.
Yet therapies using BanLec could be cheaper to create than current anti-retroviral medications which use synthetically produced components, plus BanLec may provide a wider range of protection, researchers say.
"The problem with some HIV drugs is that the virus can mutate and become resistant, but that's much harder to do in the presence of lectins," says lead author Michael D. Swanson, a doctoral student in the graduate program in immunology at the University of Michigan Medical School.
"Lectins can bind to the sugars found on different spots of the HIV-1 envelope, and presumably it will take multiple mutations for the virus to get around them," he says.
Swanson is developing a process to molecularly alter BanLec to enhance its potential clinical utility. Clinical use is considered years away but researchers believe it could be used alone or with other anti-HIV drugs as a vaginal microbicide that prevents HIV infection.
Authors say even modest success could save millions of lives. Other investigators have estimated that 20 percent coverage with a microbicide that is only 60 percent effective against HIV may prevent up to 2.5 million HIV infections in three years.

Good Friends, Rather Than Close Family Ties, Help You Live Longer In Older Age

ScienceDaily (June 16, 2005) — A network of good friends, rather than close family ties, helps you live longer in older age, suggests research in the Journal of Epidemiology and Community Health.

The research team drew on data from the Australian Longitudinal Study of Aging (ALSA), which began in 1992 in Adelaide, South Australia. The study aimed to assess how economic, social, behavioural and environmental factors affected the health and wellbeing of people aged 70 and upwards.
In total, almost 1500 people were asked how much personal and phone contact they had with their various social networks, including children, relatives, friends, and confidants.
Survival was monitored over 10 years. The group was monitored annually for the first four years of the study and then at approximately three yearly intervals.
The research team also considered the impact of factors likely to influence survival rates, such as socioeconomic status, health, and lifestyle.
Close contact with children and relatives had little impact on survival rates over the 10 years. But a strong network of friends and confidants significantly improved the chances of survival over that period.
Those with the strongest network of friends and confidants lived longer than those with the fewest friends/confidants.
The beneficial effects on survival persisted across the decade, irrespective of other profound changes in individuals' lives, including the death of a spouse or close family members, and the relocation of friends to other parts of the country.
The authors speculate that friends may influence health behaviours, such as smoking and drinking, or seeking medical help for troubling symptoms. Friends may also have important effects on mood, self esteem, and coping mechanisms in times of difficulty.
An accompanying editorial suggests that feeling connected to others may provide meaning and purpose that is not only essential to the human condition, but also to longevity, conferring a positive physiological effect on the body in the same way that stress confers a negative effect.

Genetics Of Popularity: Genetic Influence In Social Networks Identified

ScienceDaily (Jan. 27, 2009) — Can't help being the life of the party? Maybe you were just born that way. Researchers from Harvard University and the University of California, San Diego have found that our place in a social network is influenced in part by our genes, according to new findings published in the Proceedings of the National Academy of Sciences.

This is the first study to examine the inherited characteristics of social networks and to establish a genetic role in the formation and configuration of these networks.
The research was conducted by Nicholas Christakis of Harvard, who is professor of sociology in the Faculty of Arts and Sciences and professor of medical sociology at Harvard Medical School, Christopher Dawes and James Fowler, both of UC San Diego.
"We were able to show that our particular location in vast social networks has a genetic basis," says Christakis. "In fact, the beautiful and complicated pattern of human connection depends on our genes to a significant measure."
While it might be expected that genes affect personality, these findings go further, and illustrate a genetic influence on the structure and formation of an individual's social group.
The researchers found that popularity, or the number of times an individual was named as a friend, and the likelihood that those friends know one another, were both strongly heritable. Additionally, location within the network, or the tendency to be at the center or on the edges of the group, was also genetically linked. However, the researchers were surprised to learn that the number of people named as a friend by an individual did not appear to be inherited.
The study included national data (from the National Longitudinal Study of Adolescent Health) for the social networks of 1,110 adolescent twins, both fraternal and identical. The researchers compared the social networks of the identical twins to those of the fraternal twins, and found greater similarity between the identical twins' social network structure than the fraternal twins' networks.
There may be an evolutionary explanation for this genetic influence and the tendency for some people to be at the center while others are at the edges of the group, according to the researchers. If a deadly germ is spreading through a community, individuals at the edges are least likely to be exposed. However, to gain access to important information about a food source, being in the center of the group has a distinct benefit.
"One of the things that the study tells us is that social networks are likely to be a fundamental part of our genetic heritage," says Fowler, associate professor of political science at UC San Diego. "It may be that natural selection is acting on not just things like whether or not we can resist the common cold, but also who it is that we are going to come into contact with."
The findings also illuminate a previously unknown limitation of existing social network models, which had assumed that all members behave as interchangeable cogs. To address these intrinsic differences in human beings that contribute to the formation of social networks, the researchers have created a new mathematical model, called the "attract and introduce" model, which is also explained in this paper and supports the genetic variation of members.
This model creates networks that very closely simulate actual human social networks, and using this model, they found that when someone was placed in any virtual network, they gravitated towards the same place within the network.
Because both health behaviors and germs spread through social networks, understanding how contagions flow through social networks has the potential to improve strategies for addressing public health concerns such as obesity or the flu.
"I think that going forward, we are going to find that social networks are a critical conduit between our genes and important health outcomes," says Fowler.
Fowler and Christakis have also published on other aspects of social networks, such as the spread of obesity, smoking, and happiness.
The research was funded by the National Institute on Aging and the National Science Foundation.

Sleep Deprivation Influences Drug Use in Teens' Social Networks, Study Finds

ScienceDaily (Mar. 20, 2010) — Recent studies have shown that behaviors such as happiness, obesity, smoking and altruism are "contagious" within adult social networks. In other words, your behavior not only influences your friends, but also their friends and so on. Researchers at the University of California, San Diego and Harvard University have taken this a step farther and found that the spread of one behavior in social networks -- in this case, poor sleep patterns -- influences the spread of another behavior, adolescent drug use.


The study, led by Sara C. Mednick, PhD, assistant professor of psychiatry at the University of California, San Diego School of Medicine and the VA San Diego Healthcare System, will be published March 19 in PLoS ONE.
"This is our first investigation of the spread of illegal drug use in social networks," said Mednick. "We believe it is also the first study in any age population on the spread of sleep behaviors through social networks."
Using social network data from the National Longitudinal Study of Adolescent Health, Mednick and her colleagues James H. Fowler, UCSD Department of Political Science and Nicholas A. Christakis, Harvard Medical School, mapped the social networks of 8,349 adolescents in grades 7 through 12. They found clusters of poor sleep behavior and marijuana use that extended up to four degrees of separation (to one's friends' friends' friends' friends) in the social network.

Another novel network effect that they discovered was that teens who are at the center of the network are at greater risk of poor sleep, which in turn means they are more likely to use marijuana -- putting them at the crossroads of two behaviors increases a teenager's vulnerability.
Contrary to the general assumption that drug use has a negative effect on sleep, the researchers also found that sleep loss is likely to drive adolescents to use drugs -- the less they sleep the more likely their friends are to sleep poorly and use marijuana.
"Our behaviors are connected to each other and we need to start thinking about how one behavior affects our lives on many levels," said Mednick. "Therefore, when parents, schools and law enforcement want to look for ways to influence one outcome, such as drug use, our research suggests that targeting another behavior, like sleep, may have a positive influence. They should be promoting healthy sleep habits that eliminate behaviors which interfere with sleep: take the TV out of the child's bedroom, limit computer and phone usage to daytime and early evening hours, and promote napping."
The research was funded by the National Institute of Mental Health, National Institute on Aging and National Institute of Child Health and Human Development.
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