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ScienceDaily — People with medium levels of HIV in their blood are likely to contribute most to the spread of the virus, according to new research published in the journal Proceedings of the National Academy of Sciences.
The study, by researchers from Imperial College London, looked at several groups of HIV-positive people in Europe, the USA and sub-Saharan Africa. It found that those with a high viral load are the most infectious group, but have only limited time to infect others, because they generally progress to AIDS quite quickly.
Viral load - a count of how many viral particles are in a person's blood -- varies hugely between individuals. The higher the viral load, the more infectious a person is but the shorter their life expectancy. As a result, the study found, those with a high viral load do not contribute the most in the long run to the spread of HIV.
Those with a medium viral load are moderately infectious but remain asymptomatic for a period of about six to eight years before progressing to the symptoms of AIDS. This means they can be unaware that they have HIV for a long period of time, during which they can transmit the virus to a number of different sexual partners, and hence contribute most to the epidemic.
Dr Deirdre Hollingsworth, one of the authors of the paper from the Department of Infectious Disease Epidemiology at Imperial College, said: "Just being highly infectious isn't enough, you have to live long enough to pass the virus on. This long-term view should inform public health policy."
Despite much recent progress, effective treatment is still not widely available across sub-Saharan Africa, where most infected individuals live. One idea which has been put forward is that treatment should target the most infectious people, with high viral loads, in order to limit transmission. The results of the new study suggest that this would not be an effective plan, as the largest number of new infections is caused by people with medium viral loads.
Those with a medium viral load form the largest, most common group amongst those not receiving treatment. One reason for this could be that the virus has evolved to achieve the optimal balance between infectiousness and virulence, in order to maximise its chances of getting passed on.
Dr William Hanage, another of the authors from the same department at Imperial, commented: "It's certainly very striking that the viral loads we see most in nature are just right to make sure the virus gets transmitted as much as it can before it kills its host, which is what you would expect from evolution."
Dr Christophe Fraser, lead author of the study from the Department of Infectious Disease Epidemiology at Imperial College, added: "We now want to see whether the virus has adapted in order to allow it to infect the most people, which seems plausible given the results of our study. This would have serious implications for public health policy, because if it is true then some strategies to prevent transmission could end up making the virus more virulent by accident. While it is too early to sound the alarm, more research to prove or disprove this theory is urgently needed. That is what we are focusing on now."
Men who consume a higher amount of whole grain breakfast cereals may have a reduced risk of heart failure, according to a report in the October 22 issue of Archives of Internal Medicine.
The lifetime risk of heart failure is estimated at 20 percent (one in five) for both men and women aged 40 years," according to background information in the article. Studies have suggested that the risk of hypertension, coronary heart disease, hypercholesterolemia (high blood cholesterol) and mortality can be reduced with a diet rich in grain products.
Luc Djousse, M.D., M.P.H., D.Sc. and Michael Gaziano, M.D., M.P.H. of the Brigham and Women's Hospital (BWH) and and Harvard Medical School, Boston, analyzed the association between breakfast cereal intake and new cases of heart failure among 21,376 men (average age 53.7) participating in the Physician's Health Study I. Cereal intake was estimated by using a food frequency questionnaire and incident heart failure was assessed by annual follow-up questionnaires for an average of 19.6 years.
During follow-up, 1,018 of the participants experienced heart failure. This included 362 of 6,995 participants who did not eat any cereal, 237 of 4,987 of those who ate one serving or less per week, 230 of 5,227 of those who ate two to six servings per week and 189 of 4,167 of those who ate seven or more servings per week.
"Our data demonstrate that a higher intake of whole grain breakfast cereals is associated with a lower risk of heart failure," the authors conclude. This association may be due to the beneficial effects of whole grains on heart failure risk factors such as hypertension, myocardial infarction [heart attack], diabetes mellitus and obesity. "If confirmed in other studies, a higher intake of whole grains along with other preventive measures could help lower the risk of heart failure."
Reference: Arch Intern Med. 2007;167(19):2080-2085.
The PHS is supported by grants from the National Cancer Institute and grants from the National Heart, Lung and Blood Institute (NHLBI), Bethesda, Maryland. Dr. Djousse is supported by a grant from the NHLBI
In spring 2005 a large European research and training network was established to investigate the causes and implications of poor sleep from a medical as well as from a social point of view.
The topic of the project is important and timely: our environment is changing to a 24/7 society, which inevitably means that time spent in sleep decreases. What are the consequences of this reduction for human health and well-being?
The training network consists of 16 young Marie Curie Fellows from 12 countries, who are trained in the six consortium laboratories by experienced mentors. They are researching the role of sleep in the quality of life; in mood disorders, and how it can affect performance, accident rates, and cardiovascular diseases.
Animal models complement the project aiming to understand the basic mechanisms underlying sleep regulation and thereby provide recommendations for the development of new hypnotics.
The Helsinki group has investigated the effect of partial sleep loss on human health using an experimental setup that resembles a normal working week. They found that following sleep restriction to 4 hours per night, an individual's ability to perform complex tasks gradually decreased during the five days. Several changes in their immunological system were also recognized, e.g. increase in CRP (C-reactive protein), an indicator of defense reaction.
The Sociology of Sleep Group at the University of Surrey has shown the diverse ways in which the social context of everyday life has profound influences on sleep quality. Indepth interviews with women in Italy show how women's sleep is severely disrupted by care-giving roles, especially for frail elderly relatives.
Analysis of large-scale surveys has found strong social inequalities in sleep problems with poorer sleep recorded for people living in more disadvantaged social circumstances, such as with low income and low educational attainment.
The Chronobiology Group at the University of Surrey has been investigating the effect of blue short wavelength light on circadian rhythms and sleep in the young and elderly. A reduced responsiveness to short wavelength light has been observed in older people and this may have implications for the design of lighting in elderly homes.
The group in Munich and Ingolstadt has first evidence for an influence of a chronic sleep disorder going along with severe sleepiness (narcolepsy) on the processing of emotional stimuli in the brain, suggesting that disturbed sleep regulation profoundly interferes with our well being and the interaction with the environment.
Basic research in the human sleep research laboratory of the University of Zurich revealed clear age-related changes in the impairment of sustained vigilant attention after one night without sleep. This finding is consistent with epidemiological studies and has important implications for the prevention of accidents associated with the loss of sleep.
The group from the University of Zurich, dedicated to animal research, recorded sleep in different mouse models under normal conditions and under enhanced sleep pressure attained by sleep deprivation of a few hours. The effect of pharmacological stimulation of different types of GABAA receptors was investigated. This research aims at opening new avenues for the development of hypnotics. The hypnotic efficacy, when based on normal sleep physiology, should be optimized and lead to less adverse effects.
The mentors recognize the pressing need to bring the results of this research network available to all people. Training of the Fellows includes, in addition to the scientific training, also training in communication with the general public. The Fellows are encouraged to write articles and give general presentations -- each of them has written a description of their work, which is available on the website (http://www.sleep.fi) of the project.
This EU-financed sleep research project, "The biomedical and sociological effects of sleep restriction", is coordinated by Dr. Tarja Porkka-Heiskanen (Stenberg) MD, PhD, at the University of Helsinki, Institute of Biomedicine. Although the work is only half way through, interesting results have already emerged, and the project has now been nominated as one of the "success stories" among EU-funded projects.
The other partners are from UK (University of Surrey), Belgium (Universite Libre de Bruxelles), Germany (Max Planck Institute for Psychiatry & Center of Mental Health, Klinikum Ingolstadt) and Switzerland (University of Zurich).
Dr. Peter Lawrence, UCLA's chief of vascular surgery, picks up size 7 crochet hooks from a fabric store -- not to make sweaters or scarves but to use in a new technique he has developed to treat varicose veins
Early results of the new outpatient procedure, called light-assisted stab phlebectomy, or LASP, appear in a study in the October issue of the journal The American Surgeon.
More than 250 patients at UCLA have undergone Lawrence's procedure, which is designed to remove branch varicose veins from the thighs, calves and ankles. The technique combines two current varicose vein-removal methods -- powered phlebectomy and stab phlebectomy -- which excise veins through a small incision in the skin. Lawrence's method also employs transilllumination, in which a light source is placed beneath the skin to help highlight the veins during the procedure.
In addition, Lawrence has developed new, minimally invasive surgical instruments to remove the veins.
"This new, sutureless technique allows complete and rapid varicose branch vein removal with few missed varicose veins, little bruising and an excellent cosmetic result," said Lawrence, author of the study and a professor at the David Geffen School of Medicine at UCLA.
Varicose veins affect over 40 percent of the adult population, mostly women. The inherited condition occurs frequently in the legs, where weakened valves in the veins lack the strength to push blood back to the heart, allowing it to pool in the lower extremities.
During the LASP procedure, in which the patient is sedated but remains conscious, Lawrence makes a tiny incision near the varicose veins and threads a slender tube with a light source at its tip underneath the vein cluster.A mixture of saline, lidocaine and epinephrine is infused into the area, providing a further anesthetic and "plumping up" the veins so that they are easily visible. The lights of the operating room are turned off so that Lawrence can see the veins illuminated under the skin.
"This is one of the first times that transillumination is used during the actual vein-removal procedure, which offers maximum visibility for the surgeon," Lawrence said. "Usually the veins are mapped before the procedure, which is not as effective."
Lawrence then makes a very small incision immediately adjacent to a varicose vein. Taking a size 7 crochet hook that has been filed down and modified for the procedure, he passes it through the incision, hooks a vein and pulls it through the opening. After turning on the operating room lights, Lawrence assesses the vein, sets the crochet hook aside and grasps the vein at its base with a tiny mosquito clamp. Using a gentle circular motion, he dislodges the vein from the skin. Further incisions are made to remove remaining veins.
The empty vein channels are flushed with solution to help collapse them and prevent bruising and hematomas from any residual blood remaining in the channels. No sutures are used; this allows for continued drainage if needed. A compression dressing is applied to the affected area, and within an hour, the patient goes home with instructions to elevate the leg for 48 hours. The resulting scars look like small freckles.
Between 2004 and 2006, 268 patients received LASP treatment at UCLA -- 49 of them underwent LASP alone, and 184 had it combined with another varicose vein-removal procedure. Researchers followed up with patients roughly a year after their procedures and found few early postoperative complications, such as infection, hematoma formation or severe pain requiring additional pain prescriptions.
According to Lawrence, LASP may provide lower residual varicose vein occurrence due to the greater ease in identifying the veins in the operating room through transillumination.
The next step is a larger study and longer follow-up with patients, Lawrence said.
Currently, various procedures are used to treat varicose veins, depending on their size. In addition to powered stab phlebectomy, other methods include laser and radiofrequency treatments, which employ heat or energy to seal off veins; vein ligation and stripping, surgical procedures that involving the tying off or removal of veins;
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