Hearing loss affects old people’s personality

As people approach old age, they generally become less outgoing. New research from the University of Gothenburg shows that this change in personality is amplified among people with impaired hearing. The findings emphasise the importance of acknowledging and treating hearing loss in the elderly population.The researchers studied 400 individuals 80-98 years old over a six-year period. Every two years, the subjects were assessed in terms of physical and mental measures as well as personality aspects such as extraversion, which reflects the inclination to be outgoing, and emotional stability. The results show that even if the emotional stability remained constant over the period, the participants became less outgoing.Interestingly, the researchers were not able to connect the observed changes to physical and cognitive impairments or to age-related difficulties finding social activities. The only factor that could be linked to reduced extraversion was hearing loss.’To our knowledge, this is the first time a link between hearing and personality changes has been established in longitudinal studies. Surprisingly, we did not find that declining overall health and functional capacity make people less outgoing. But hearing loss directly affects the quality of social situations. If the perceived quality of social interaction goes down, it may eventually affect whether and how we relate to others,’ says Anne Ingeborg Berg, PhD, licensed psychologist and researcher at the Department of Psychology, University of Gothenburg.The study yields interesting knowledge about personality development late in life, and also points to the importance of acknowledging and treating hearing loss among the elderly.The utilisation of hearing aids did not affect the correlation found, which suggests that there is a need for support in the use of aids such as hearing devices.’Our previous studies have shown that outgoing individuals are happier with their lives. It is hypothesised that an outgoing personality reflects a positive approach to life, but it also probably shows how important it is for most people to share both joy and sadness with others. …

Read more

Medical marijuana may ease some MS; Little evidence for other complementary or alternative therapies

A new guideline from the American Academy of Neurology suggests that there is little evidence that most complementary or alternative medicine therapies (CAM) treat the symptoms of multiple sclerosis (MS). However, the guideline states the CAM therapies oral cannabis, or medical marijuana pills, and oral medical marijuana spray may ease patients’ reported symptoms of spasticity, pain related to spasticity and frequent urination in multiple sclerosis (MS). The guideline, which is published in the March 25, 2014, print issue of Neurology, the medical journal of the American Academy of Neurology, states that there is not enough evidence to show whether smoking marijuana is helpful in treating MS symptoms.The guideline looked at CAM therapies, which are nonconventional therapies used in addition to or instead of doctor-recommended therapies. Examples include oral cannabis, or medical marijuana pills and oral medical marijuana spray, ginkgo biloba, magnetic therapy, bee sting therapy, omega-3 fatty acids and reflexology.”Using different CAM therapies is common in 33 to 80 percent of people with MS, particularly those who are female, have higher education levels and report poorer health,” said guideline lead author Vijayshree Yadav, MD, MCR, with Oregon Health & Science University in Portland and a member of the American Academy of Neurology. “People with MS should let their doctors know what types of these therapies they are taking, or thinking about taking.”For most CAM therapies, safety is unknown. There is not enough information to show if CAM therapies interact with prescription MS drugs. Most CAM therapies are not regulated by the Food and Drug Administration (FDA). Dronabinol and nabilone are synthetic forms of key ingredients in marijuana. The FDA approved both drugs as treatments for nausea and vomiting associated with cancer chemotherapy that do not respond to standard treatments. Dronabinol also is approved for loss of appetite associated with weight loss in patients with AIDS.The guideline found that certain forms of medical marijuana, in pill or oral spray form only, may help reduce patients’ reported spasticity symptoms, pain due to spasticity, and frequent urination but not loss of bladder control. …

Read more

Reducing HIV transmission among drug injectors lowers AIDS mortality in heterosexuals

Although community network studies show that sexual relationships occur between members of “risk groups” — men who have sex with other men (MSM), people who inject drugs (PWID), non-injection drug users (NIDU) — and heterosexuals, researchers at New York University’s Center for Drug Use and HIV Research (CDUHR) note that little research has been done to help explain how HIV epidemics and programs in one population affect others and how to reduce the risks of transmission.A recent study conducted by researchers from CDUHR, led by Samuel R. Friedman, Director of both CDUHR’s Interdisciplinary Theoretical Synthesis Core, and the Institute for Infectious Disease Research at NDRI, sheds light on the pathways connecting HIV epidemics in different populations.It shows that programs for people who use drugs — like syringe exchange, HIV counseling and testing, and drug abuse treatment — are associated with subsequent lower rates of AIDS incidence and death among heterosexuals.”Since existing theory and research have relatively little to say about the cross-population processes being studied, we used exploratory analytic technique to study these relationships,” explains Dr. Friedman.The objective of the study, “Do metropolitan HIV epidemic histories and programs for people who inject drugs and men who have sex with men predict AIDS incidence and mortality among heterosexuals?” was to better understand how epidemics among MSMs and PWIDs correlate with later epidemics and mortality within heterosexuals; how prevention programs targeting specific groups affect future epidemics among other populations; and whether the size of MSM and PWID populations are associated with the later epidemics and mortalities among heterosexuals. The study was published in the Annals of Epidemiology.The study looked at data from 96 large US metropolitan statistical areas (MSAs) from 1992 — 2008. “We have only limited ability to study the mechanisms by which our independent variables come to be associated with outcomes,” explains Dr. Friedman. “Research into whether interventions in one key population affect HIV epidemics in other key populations is of high policy relevance and should be a priority.”Although the study highlights the necessity of future studies, it found that HIV counseling and testing in PWIDs was associated with lower AIDS incidence in heterosexuals, while counseling and testing in MSMs were not; and that availability of syringe exchange programs and drug abuse treatment programs were associated with lower AIDS death rates among heterosexuals.The study also highlights a link between racial/ethnic residential segregation and rates of AIDS incidence and mortality among heterosexuals and points to evidence pairing social causations like income inequality with mortality.”Our findings are descriptive of the relationships of the measured variables in these large metropolitan areas,” said Dr. Friedman. “They do not, however, imply that these findings can necessarily be extended to smaller MSAs, non-metropolitan localities, other time periods or other countries, for that further research is clearly needed.”Story Source:The above story is based on materials provided by New York University. Note: Materials may be edited for content and length.

Read more

Thinking skills take biggest hit from anxiety in midlife women with HIV

Hot flashes, depression, and most of all, anxiety, affect the thinking skills of midlife women with HIV, so screening for and treating their anxiety may be especially important in helping them function, according to a study just published online in Menopause, the journal of The North American Menopause Society (NAMS). The reproductive stage, whether it was premenopause, perimenopause or postmenopause, did not seem to be related to these women’s thinking skills.The conclusions come from a new analysis of data on 708 HIV-infected and 278 HIV-uninfected midlife women from the Women’s Interagency HIV Study (WHIS), a national study of women with HIV at six sites across the country (Chicago, Bronx, Brooklyn, San Francisco, Los Angeles, and Washington, DC). Today, nearly 52% of persons with HIV/AIDS are 40 to 54 years old. Because more women with HIV are now living to midlife and beyond, it is important to understand what challenges menopause pose for them. We learned just recently, from a study published online in Menopause in July, that women with HIV do face a bigger menopause challenge than uninfected women because they have worse menopause symptoms.Whether, how, and when the process of transitioning through menopause affects cognition have been debated. Large-scale studies of healthy women indicate that the menopause-related thinking deficiencies are modest, limited to the time leading up to menopause (“perimenopause”), and rebound after menopause. But in these women who underwent mental skills testing, menopause symptoms and mood symptoms did affect thinking skills.Mental processing speed and verbal memory were more related to depression, anxiety, and hot flashes in both HIV-infected and healthy women than the stage of menopause. Hot flashes in particular correlated with slightly lower mental processing speed, a skill that is also affected by the HIV virus. Depression correlated with decreased verbal memory, processing speed, and executive function (such as planning and organizing).Of all the symptoms measured, anxiety stood out as having the greatest impact on thinking skills, and the impact was much greater on women with HIV. Anxiety particularly affected their verbal learning skills. …

Read more

Helper cells trigger potent responses to HIV

Sep. 12, 2013 — A major new finding that will significantly advance efforts to create the world’s first antibody-based AIDS vaccine was published today by researchers from the La Jolla Institute for Allergy and Immunology.La Jolla Institute scientist Shane Crotty, Ph.D., a respected vaccine researcher and member of one of the nation’s top AIDS vaccine consortiums, showed that certain helper T cells are important for triggering a strong antibody response against HIV, the virus that causes AIDS. Helper T cells are disease-fighting immune cells key in shaping the body’s response to viruses or other pathogens. The cells are multi-faceted, come in various types, and have numerous functions, including assisting with antibody production.”We’ve shown that a specific type of these cells, known as follicular helper T (Tfh) cells are not only necessary, but are a limiting factor that differentiates between an average and a potent antibody response to HIV,” says Crotty, a scientific collaborator with the Center for HIV/AIDS Vaccine Immunology & Immunogen Discovery (CHAVI-ID), a major research consortium led by The Scripps Research Institute.Notably, Crotty showed that the frequency of the Tfh cells correlated with development of broadly neutralizing antibodies against HIV in a large group of HIV-infected individuals. The International AIDS Vaccine Initiative put together the group of study participants, and collaborated on the analysis.Dennis Burton, Ph.D., a prominent HIV expert who heads the CHAVI-ID consortium at Scripps, calls the finding “the kind of fundamental basic research that will eventually allow us to defeat HIV.””Shane Crotty and his collaborators have made an important step in understanding how potent antibodies to HIV can be made, a step which is vital to the effort to develop an AIDS vaccine given that antibodies are critical to most successful vaccines,” says Burton. “Crotty is a world expert on the cells that control antibody production and, by teaming up with AIDS researchers, he and his group have shown how these cells can be tracked in blood and provided evidence of their importance in generating the right types of antibody to HIV.”The findings were published online today in the journal Immunity in a paper entitled, “Human circulating PD-1+CXCR3-CXCR5+ memory Tfh cells are highly functional and correlate with broadly neutralizing HIV antibody responses.”Antibodies may be thought of as the body’s smart bombs, which seek out infectious agents and tag them for destruction. Twenty-six human vaccines currently exist worldwide, 24 of which work by triggering the production of antibodies. Tfh cells are a type of CD4+ T helper cells specialized in providing help to B cells, which are the cells that make antibodies. “Essentially it’s the Tfh cells that tell the B cells to produce antibodies,” explains Crotty.No vaccine currently exists for HIV (human immunodeficiency virus) and there is no cure for AIDS (acquired immune deficiency syndrome), which currently infects 34 million around the globe. While AIDS drugs have extended the lives of many sufferers, AIDS remains a major killer, particularly in developing countries, making the search for an effective HIV vaccine a public health priority.In his study, Crotty used blood samples from HIV-infected patients and a control group of people without the disease. …

Read more

New report: Call for President Obama urged to ‘remove public veil of ignorance’ around state of US health

Aug. 29, 2013 — In a call to action on the sorry comparative state of U.S. health, researchers at Columbia University’s Mailman School of Public Health are urging President Obama to “remove the public veil of ignorance” and confront a pressing question: Why is America at the bottom? The report, published in the journal Science, appeals to the President to mobilize government to create a National Commission on the Health of Americans. The researchers underscore the importance of this effort in order for the country to begin reversing the decline in the comparative status of U.S. health, which has been four decades in the making.Share This:This is not a challenge that can be left to private groups, no matter how well meaning. Drs. Ronald Bayer and Amy Fairchild, both Professors of Sociomedical Sciences, argue, “The health status of Americans is a social problem that demands social solutions.” More is at stake than the U.S. healthcare system, which fails to provide needed care to millions of Americans. “There is a need for bold public policies that move beyond individual behavior to address the fundamental causes of disease,” Bayer and Fairchild conclude.A January 2013 report by the U.S. …

Read more

Learning from a virus: Keeping genes under wraps

July 30, 2013 — An international collaboration of researchers including Felicia Goodrum of the University of Arizona’s immunobiology department has studied how a human herpes virus carried by the majority of the population packages its genetic information during infection.The discoveries improve the chances of developing more targeted therapies in place of existing drugs, which do not always work or come with side effects.Experts estimate that 60 to 90 percent of the world’s population carry the human cytomegalovirus, or CMV, which is one of the eight herpes viruses that infect humans.In healthy individuals, the virus lies dormant and does not cause overt disease. However, it poses a significant risk when contracted by unborn children — whose immune system has not matured yet — and individuals with compromised immune function.CMV is the leading cause of birth defects resulting from any infectious agent. It affects one in 150 births in the US and most commonly results in hearing loss, but can also cause cognitive or physical anomalies and cerebral palsy. Once infected, the virus stays in the body for life and flares up only when the immune system is suppressed, for example in AIDS patients, transplant patients and cancer patients undergoing intensive chemotherapy.For the study, published in the scientific journal Proceedings of the National Academy of Sciences (PNAS), Goodrum teamed up with collaborators in Germany and Israel.The researchers investigated how a fundamental aspect of the human cell regulates the virus: the mechanism by which genetic information is packaged and stored. Understanding how the viral DNA behaves in the human host cells during dormancy and reactivation of the virus provides the basis for the development of drugs that could prevent the virus from “waking up” and causing disease.”The human immune system is very sophisticated, and the way this virus has managed to stealthily integrate into our biology to ensure its own survival is no small feat,” said Goodrum, also a member of the UA’s BIO5 Institute.”CMV is a master of human cell biology. From transcribing DNA into blueprints for proteins to the manufacturing of those proteins, from cell division to cellular metabolism, there is not a process this virus has not tweaked,” Goodrum also said.That mastery, she explained, is the reason the virus is so elusive to vaccine, and there currently is no way to eradicate it. Goodrum noted that with other herpes viruses, like Epstein-Barr or chicken pox, the infection is obvious. But that is not the case with CMV.”From the perspective of a virus, that is the pinnacle of mastery — to infect without ever making its presence known,” Goodrum said.”To develop more effective antiviral strategies, we must understand the biology of the virus infection and how the virus manages to persist for our lifetimes,” she said. “We are trying to understand how our cellular mechanisms are being used by this virus and discover targets for drugs to control it.”Each human cell contains a thread of DNA that is about 6 feet long, stowed away in its nucleus and tightly packaged by proteins called histones. One such package of genetic material is called a chromosome.”You can imagine histones as a spool, and the thread is DNA that wraps around the spool,” Goodrum said. …

Read more

New approach to treating venomous snakebites could reduce global fatalities

July 30, 2013 — A team of researchers led by Dr. Matt Lewin of the California Academy of Sciences, in collaboration with the Department of Anesthesia at the University of California, San Francisco, has pioneered a novel approach to treating venomous snakebites — administering antiparalytics topically via a nasal spray. This new, needle-free treatment may dramatically reduce the number of global snakebite fatalities, currently estimated to be as high as 125,000 per year.The team demonstrated the success of the new treatment during a recent experiment conducted at UCSF; their results have been published in the medical journal Clinical Case Reports.Snakebite is one of the most neglected of tropical diseases — the number of fatalities is comparable to that of AIDS in some developing countries. It has been estimated that 75% of snakebite victims who die do so before they ever reach the hospital, predominantly because there is no easy way to treat them in the field. Antivenoms provide an imperfect solution for a number of reasons — even if the snake has been identified and the corresponding antivenom exists, venomous bites often occur in remote locations far from population centers, and antivenoms are expensive, require refrigeration, and demand significant expertise to administer and manage.”In addition to being an occupational hazard for field scientists, snakebite is a leading cause of accidental death in the developing world, especially among otherwise healthy young people,” says Lewin, the Director of the Center for Exploration and Travel Health at the California Academy of Sciences. “We are trying to change the way people think about this ancient scourge and persistent modern tragedy by developing an inexpensive, heat-stable, easy-to-use treatment that will at least buy people enough time to get to the hospital for further treatment.”In his role as Director of the Academy’s Center for Exploration and Travel Health, Lewin prepares field medicine kits for the museum’s scientific expeditions around the world and often accompanies scientists as the expedition doctor. In 2011, Lewin put together snakebite treatment kits for the Academy’s Hearst Philippine Biodiversity Expedition, which would have required scientists to inject themselves if they needed treatment. When he saw their apprehension about the protocol, Lewin began to wonder if there might be an easier way to treat snakebite in the field.In some fatal snakebites, victims are paralyzed by the snake’s neurotoxins, resulting in death by respiratory failure. A group of common drugs called anticholinesterases have been used for decades to reverse chemically-induced paralysis in operating rooms and, in intravenous form, to treat snakebite when antivenoms are not available or not effective. However, it is difficult to administer intravenous drugs to treat snakebite outside of a hospital, so Lewin began to explore the idea of a different delivery vehicle for these antiparalytics — a nasal spray.In early April of 2013, Lewin and a team of anesthesiologists, led by Dr. …

Read more

Is a common food fungus worsening the AIDS epidemic?

July 23, 2013 — A type of fungus coating much of the stored corn, wheat, rice and nuts in developing countries may be quietly worsening the AIDS epidemic, according to a paper published today in the World Mycotoxin Journal.Kept in sacks piled in barns and warehouses, food stores in countries near the equator are contaminated by Aspergillus flavus and A. parasiticus, fungi that produce a toxic substance called aflatoxin. About 4.5 billion people worldwide are exposed to aflatoxin at unsafe levels, and chronic exposure has been linked to liver damage and related cancers; but its role in the spread of infectious disease could make it even more deadly.”Our work suggests study that aflatoxin exposure may be taking an even greater toll in areas where millions are infected with HIV, including Africa and Asia, the latter with a fast-growing HIV population and rice storage areas contaminated by fungi,” said Pauline, Jolly, Ph.D., professor in the Department of Epidemiology within the School of Public Health at the University of Alabama at Birmingham (UAB). Strict regulation and monitoring minimize exposure in the United States.Jolly and her colleagues recruited 314 HIV-positive people who were not yet on antiretroviral therapy for the study in Kumasi, Ghana. They divided patients into four groups based on their level of aflatoxin exposure and found that those in the highest exposure group were 2.6 times more likely to have a high HIV viral load than those in the lowest exposure group. Higher viral load translates into higher rates of HIV transmission and the potential for earlier progression to the opportunistic infections of AIDS.”Previous studies by our team had looked at the possible interaction of aflatoxin and HIV on immune suppression, and this study examined twice as many patients as previous studies,” said Jolly, the study’s corresponding author. “It also was structured to eliminate factors such as opportunistic infections and antiviral combination therapy in clarifying the relationship between aflatoxin exposure and HIV for the first time.”Leading theories suggest that the fungal toxin may suppress the immune system by reducing the production of certain immune cells or the proteins that activate them. The toxin also may increase the expression of genes that result in more copies of the virus, but more study is needed to confirm the mechanisms.Along with Jolly, the study authors were Seidu Inusah and Baogen Lu, M.D., in the UAB departments of Biostatistics and Epidemiology; William Ellis, Ph.D., Kwame Nkrumah University of Science and Technology in Kumasi; Alberta Nyarko, M.D., Kumasi South Regional Hospital in Kumasi; Timothy Phillips, Ph.D., Texas A & M University Department of Veterinary Integrative Biosciences; and Jonathan Williams, Ph.D., University of Georgia College of Agricultural and Environmental Science.This research was supported by a grant by the U.S. Agency for International Development (LAG-G-00-96-90013-00) plus support from the Centers for Disease Control and Prevention and National Institute on Minority Health and Health Disparities.”We have done a series of studies now confirming a link between HIV viral load and aflatoxin exposure, but the problem has not yet been recognized or addressed,” said Jolly, an HIV immunologist who does most of her work in Ghana. “While this study was larger than our previous study, a fungal contribution to HIV transmission will only be proved once and for all by larger randomized studies for which there now is no funding. …

Read more

Lifesaving HIV treatment could reach millions more people following landmark study

July 4, 2013 — Millions more people could get access to life-saving HIV drug therapy, following a landmark study led by Australian researchers based at the Kirby Institute at the University of New South Wales (UNSW).The researchers have found a lower daily dose of an important HIV drug therapy is safe and as effective in suppressing the virus as the standard recommended dose.The findings have been presented at the International AIDS Society Conference in Kuala Lumpur, Malaysia.”This has the potential to affect the treatment of millions of HIV positive people,” says UNSW Professor Sean Emery, the protocol chairperson of the study, known as ENCORE1 and Head of the Therapeutic and Vaccine Research Program at the Kirby Institute.”A reduced daily dose should translate into a lower cost of treatment and permit more effective and efficient use of health care resources. Essentially, more people could receive this life-saving treatment for the same amount of funding.”HIV-positive people from 13 countries in Africa, Asia, Australia, Europe and Latin America took part in the trial. Half these people took two-thirds of the current standard daily dose of the antiretroviral (ART) efavirenz, a commonly used treatment for HIV; the other half took the standard daily dose. The 630 participants were observed regularly for a year. The results indicate that a reduction in daily dose of one third is both safe and effective compared to the higher dose currently recommended for people with HIV infection.The research was part of a program funded with a grant of US$12.42 million from the Bill & Melinda Gates Foundation.

Read more

Antibiotics: Change route of delivery to mitigate resistance

June 26, 2013 — New research suggests that the rapid rise of antibiotic resistance correlates with oral ingestion of antibiotics, raising the possibility that other routes of administration could reduce the spread of resistance. The manuscript appears online ahead of print in the journal Antimicrobial Agents and Chemotherapy.”For more than 40 years, a few doses of penicillin were enough to take care of deadly bacterial infections,” says Hua Wang of the Ohio State University, Columbus, a researcher on the study. But since the 1980s, antibiotic resistance has been spreading rapidly, disabling once-powerful agents, leaving increasing numbers of patients to suffer, and even to die.In earlier research, the investigators found a large cache of antibiotic resistance genes carried by nonpathogenic bacteria in many ready-to-consume food items. They also reported rapid development of resistant bacteria in infants who had not been exposed to antibiotics, shortly after birth, suggesting the gastrointestinal tract played a critical role in spreading resistance.In the new research, the researchers inoculated lab mice with either Enterococcus species or Escherichia coli carrying specific resistance genes. The mice were then given tetracycline or ampicillin antibiotics, either orally, or via injection. Oral administration of antibiotics resulted in rapid rise of resistance genes as measured in the mice’ feces. Resistance spread much less, and more slowly when the mice received antibiotics via injection.The researchers also found that antibiotic resistance genes were not detectable in mice that had not been inoculated with bacteria containing antibiotic resistance genes, regardless of the route of antibiotic administration.The human death toll from resistance, Wang says, is much higher than the 90,000 figure provided by the Centers for Disease Control and Prevention. The difference is due to the fact that bacterial infection is often the direct cause of death in many patients with chronic diseases, such as HIV/AIDS and cancer.Besides resistance, recent work has shown that the use of oral antibiotics can reduce the diversity of the gut flora. Abnormalities of the gut flora are associated with multiple non-infectious diseases, including several autoimmune diseases and type II diabetes, according to Jeremy Nicholson of Imperial College, London, UK. Thus, alternatives to oral administration could likely mitigate these kinds of problems, as well.Convenient alternatives to oral antibiotics might include transdermal administration via a patch, or other devices, says Wang.Wang suggests that it should not be surprising that oral administration would abet the spread of resistance genes, since this route, unlike injection, directly exposes the humongous population of gastrointestinal bacteria to antibiotics. …

Read more

Research IDs potential treatment for deadly, HIV-related blood cancer

June 25, 2013 — Researchers at the USC Norris Comprehensive Cancer Center have discovered a promising new way to treat a rare and aggressive blood cancer most commonly found in people infected with HIV.The USC team shows that a class of drugs called BET bromodomain inhibitors effectively targets primary effusion lymphoma (PEL), a type of cancer for which those drugs were not expected to be effective.”It’s a reversal of the paradigm,” said Preet Chaudhary, chief of the Nohl Division of Hematology and Blood Diseases at the Keck School of Medicine of USC and principal investigator of the study. “Our results suggest that this new class of drug may be an effective treatment for a wider range of cancers than previously thought.”PEL is caused by infection with Kaposi’s sarcoma-associated herpes virus, the most common cause of cancer among patients with AIDS. The prognosis for PEL is poor, with a median survival of three to six months. Thus, there is a critical need for new therapies for the disease.Chaudhary and his colleagues show that inhibitors targeting the BRD4 protein blocked growth of PEL cells in a test tube and in a mouse model. The results were surprising because BET inhibitors were thought to be only effective against cancers linked to an overexpression of the Myc gene.”We actually found that cancers that overexpress Myc are not as responsive to BRD4 inhibitors. PEL is more responsive,” Chaudhary said.Cancers like multiple myeloma and Burkitt’s lymphoma overexpress the Myc gene and have been shown to respond to BRD4 inhibitors. In PEL, the Myc gene is moderately expressed and there is no chromosomal translocation as is seen in multiple myeloma or Burkitt’s.More research is needed to create compounds ready for testing in people. Once those drugs are ready for clinical trial, data from this study suggest that they may treat a wide range of cancers. Chaudhary anticipates testing them alone and in combination with other drugs.

Read more

New approach to battling tuberculosis

June 18, 2013 — Most humans would like to shed their fatty exteriors, but tuberculosis (TB)-causing bacteria rely on theirs for survival. Scientists at the University of Medicine and Dentistry of New Jersey (UMDNJ)-New Jersey Medical School have now discovered a drug that cripples the TB bug by dissolving its protective fatty coating, a finding that could eventually be used to improve TB treatment in humans. The study has been posted online by Nature Chemical Biology.Share This:TB is caused by infection with the bacterium Mycobacterium tuberculosis (Mtb) and is the second biggest cause of death worldwide, second only to HIV/AIDS. And with drug-resistant strains of Mtb on the rise, there is a critical need for more effective anti-TB agents.”Mtb is a little ball of soap,” says lead author David Alland, MD, a professor of medicine and Director of the Center for Emerging and Re-emerging Pathogens at New Jersey Medical School, describing the meshwork of long fatty acids that make up the bug’s protective cell wall. There are a few anti-TB drugs that disrupt this coat, but so far no single drug has been able to kill the bacteria completely. So his group went in search of new and better drugs by using a simple and rapid approach. They screened for agents that trigger expression of a bacterial gene that gets turned on when cell wall synthesis is compromised.They discovered a class of compound called thiophenes that killed the Mtb in culture without the emergence of drug resistance. And the combination of thiophene and the existing coat-busting drug isoniazid achieved 100% bacterial killing. Thiophenes worked by crippling an enzyme called Pks13 that hitches two long fatty acids together to create the bug’s fatty coat. With additional information on the molecular structure of these drugs bound to Pks13, Alland hopes to discover ways to tweak the compounds to make them even more potent and less toxic.Share this story on Facebook, Twitter, and Google:Other social bookmarking and sharing tools:|Story Source: The above story is reprinted from materials provided by University of Medicine and Dentistry of New Jersey (UMDNJ), via Newswise. …

Read more

Potential disease-transmission sources in animals ID’d by calculating risk using social network mathematics

June 11, 2013 — Spanish and US scientists have successfully identified animal species that can transmit more diseases to humans by using mathematical tools similar to those applied to the study of social networks like Facebook or Twitter. Their research — recently published in the journal PNAS — describes how parasite-primate interactions transmit diseases like malaria, yellow fever or AIDS to humans. Their findings could make an important contribution to predicting the animal species most likely to cause future pandemics.Professor José María Gómez of the University of Granada Department of Ecology is the principal author of this research, in collaboration with Charles L. Nunn (University of Cambridge, Massachusetts, US) and Miguel Verdú (Spanish National Research Council Desertification Research Center, Valencia, Spain). They propose a criterion to identify disease-transmission agents based on complex network metrics similar to those used to study social networks.As Prof Gómez explains, “most emerging diseases in humans are zoonotic, that is, they are transmitted to humans by animals. To identify animal species that are potential high-risk sources of emerging diseases it’s essential we set up mechanisms that control and observe these diseases.”Study of 150 primate speciesTo conduct their study, the researchers constructed a network in which each node represented one of the approximately 150 non-human primate species about which we have enough data on their parasite fauna. “Each primate species is connected to the other primates as a function of the number of parasites they share. Once the network was constructed, we studied each primate species’ position — whether central or peripheral. A primate’s centrality is measured by its connection intensity with many other primates that are, in turn, closely connected,” says the University of Granada researcher.The article published in PNAS reports the researchers’ discovery that the most central primates could be more capable of transmitting parasites to other species and, therefore, to humans, than the rest. “This is comparable to the idea that, in social networks, web pages that are central and have links to many other pages, spread their contents all through the Web,” José María Gómez affirms.The researchers have confirmed their hypothesis by relating the centrality value of each primate with the number of emerging pathogens shared with humans. …

Read more

How do immune cells detect infections?

June 7, 2013 — How do immune cells manage to sort through vast numbers of similar-looking proteins within the body to detect foreign invaders and fight infections?”For immune cells, singling out foreign proteins is like looking for a needle in a haystack — where the needle may look very much like a straw, and where some straws may also look very much like a needle,” notes McGill University physics professor Paul François.Understanding how immune cells tackle this formidable challenge is important, because it could provide crucial insights into the understanding of immune diseases, from AIDS to auto-immune disorders.In a study published May 21 in the journal Physical Review Letters, François and McGill graduate student Jean-Benoît Lalanne used computational tools to examine what kind of solutions immune systems may use to detect small concentrations of foreign antigens (characteristic of potentially harmful infections) in a sea of “self-antigens” normally present at the surface of cells.The researchers’ computer simulations yielded a surprisingly simple solution related to the well-known phenomenon of biochemical adaptation — a general biochemical mechanism that enable organisms to cope with varying environmental conditions.To find solutions, the computer uses an algorithm inspired by Darwinian evolution. This algorithm, designed previously within the François research group, randomly generates mathematical models of biochemical networks. It then scores them by comparing properties of these networks to predefined properties of the immune system. Networks with best scores are duplicated in the next generation and mutated, and the process is iterated over many simulated “generations” until networks reach a perfect score.In this case, almost all solutions found were very similar, sharing a common core structure or motif.”Our approach provides a simpler theoretical framework and understanding of what happens” as immune cells sort through the “haystack” to detect foreign antigens and trigger the immune response, François says. “Our model shares many similarities with real immune networks. Strikingly, the simplest evolved solution we found has both similar characteristics and some of the blind spots of real immune cells we studied in a previous collaborative study with the groups of Grégoire Altan-Bonnet (Memorial Sloane Kettering, New York), Eric Siggia (Rockefeller University, New York) and Massimo Vergassola (Pasteur Institute, Paris).”Funding for the research was provided by the Natural Sciences and Engineering Research Council of Canada and the Human Frontier Science Program.

Read more

Detecting disease with a smartphone accessory

June 4, 2013 — As antiretroviral drugs that treat HIV have become more commonplace, the incidence of Kaposi’s sarcoma, a type of cancer linked to AIDS, has decreased in the United States. The disease, however, remains prevalent in sub-Saharan Africa, where poor access to medical care and lab tests only compound the problem. Now, Cornell University engineers have created a new smartphone-based system, consisting of a plug-in optical accessory and disposable microfluidic chips, for in-the-field detection of the herpes virus that causes Kaposi’s. “The accessory provides an ultraportable way to determine whether or not viral DNA is present in a sample,” says mechanical engineer David Erickson, who developed the technique along with his graduate student, biomedical engineer Matthew Mancuso. The technique could also be adapted for use in detecting a range of other conditions, from E. coli infections to hepatitis.Share This:Mancuso will describe the work at the Conference on Lasers and Electro Optics (CLEO: 2013), taking place June 9-14 in San Jose, Calif.Unlike other methods that use smartphones for diagnostic testing, this new system is chemically based and does not use the phone’s built-in camera. Instead, gold nanoparticles are combined (or “conjugated”) with short DNA snippets that bind to Kaposi’s DNA sequences, and a solution with the combined particles is added to a microfluidic chip. In the presence of viral DNA, the particles clump together, which affects the transmission of light through the solution. This causes a color change that can be measured with an optical sensor connected to a smartphone via a micro-USB port. When little or no Kaposi’s virus DNA is present, the nanoparticle solution is a bright red; at higher concentrations, the solution turns a duller purple, providing a quick method to quantify the amount of Kaposi’s DNA.The main advantage of the system compared to previous Kaposi’s detection methods is that users can diagnose the condition with little training. …

Read more

Sensitive new microphone modeled on fly ear

May 30, 2013 — Using the sensitive ears of a parasitic fly for inspiration, a group of researchers has created a new type of microphone that achieves better acoustical performance than what is currently available in hearing aids. The scientists will present their results at the 21st International Congress on Acoustics, held June 2-7 in Montreal.

Ronald Miles, Distinguished Professor of Mechanical Engineering at Binghamton University, studies the hearing of Ormia ochracea, a house fly-sized insect that is native to the southeast United States and Central America. Unlike most other flies, Ormia ochracea has eardrums that sense sound pressure, as do our ears, and they can hear “quite well,” says Miles. The female flies use their “remarkable” directional hearing to locate singing male crickets, on which they deposit their larvae.

Previously, Miles and colleagues Daniel Robert and Ronald Hoy described the mechanism by which the fly achieves its directional hearing, despite its small size. Now Miles and his group have designed a new microphone inspired by the fly’s ears.

The new design uses a microelectromechanical microphone with a 1 mm by 3 mm diaphragm that is designed to rotate about a central pivot in response to sound pressure gradients. The motion of the diaphragm is detected using optical sensors. To minimize the adverse effects of resonances on the response, Miles and his colleagues used a feedback system to achieve so-called active Q control.

“Q control basically is an electronic feedback control system to introduce electronic damping,” Miles explains. “You don’t want a microphone diaphragm to ring like a bell. It turns out that in order to achieve a very low noise floor — which is the quietest sound that can be detected without the signal being buried in the microphone’s noise — it is important to minimize any passive damping in these sensors. If you do that, the diaphragm will resonate at its natural frequency. We are the first group to show that you can use this sort of electronic damping in a microphone without adversely affecting the noise floor of the microphone.”

Indeed, the noise floor of the fly-inspired microphone is about 17 decibels lower than what can be achieved using a pair of low-noise hearing aid microphones to create a directional hearing aid. The new design could be used in applications ranging from hearing aids and cell phones to surveillance and acoustic noise control systems, Miles says, and “could easily be made as small as the fly’s ear.”

Read more

Utilizzando il sito, accetti l'utilizzo dei cookie da parte nostra. maggiori informazioni

The cookie settings on this website are set to "allow cookies" to give you the best browsing experience possible. If you continue to use this website without changing your cookie settings or you click "Accept" below then you are consenting to this.

Close