Friday, June 09, 2006

New Drug To Overcome HIV

REVOLUTIONARY drug that could help overcome HIV's growing resistance to existing antiviral drugs is about to be tested in combination with standard antivirals. Called PA-457, it is the first of a new class of anti-HIV compounds called maturation inhibitors. The drug is still in its early stages, and will not be generally available for at least three years.

Up to 80 per cent of HIV positive people on treatment show resistance to one or more of their drugs, according to Graham Allaway of Panacos Pharmaceuticals in Gaithersburg, Maryland, which is developing PA-457. Panacos hopes to begin trials this month to test how well the drug works in patients whose existing drug regimes are failing. PA-457 aims to overcome this resistance by attacking HIV on new front. Many existing drugs work by blocking reverse transcriptase, an enzyme that enables HIV to replicate within cell. Others disable protease, which helps to assemble the virus into particles that infect other cells.

Recent experiments in collaboration with Michael Sakalian and his colleagues at the University of Oklahoma Health Sciences Center in Oklahoma City have shown that PA-457 works in a different way. It attacks HIV by disrupting formation of a conical shield, called the capsid protein, which stores and protects the RNA heart of the HIV particles as they bud out from infected cells.

The latest research, in which the virus was examined under a microscope, shows that the drug binds to the capsid protein at a crucial stage in its manufacture (Journal of Virology, vol 80, p 5716). Normally, the capsid protein is clipped apart from a major structural protein called the gag protein, and is then assembled into a cone. PA-457 stops it being clipped off, causing it to form a leaky sphere that leaves the core RNA exposed (see Diagram, left). This cripples the virus, preventing it from infecting any other cells once it buds out from the host.

The trial planned for this month is intended to discover how the drug performs as part of a combination treatment with other anti-HIV drugs, which is a more realistic situation. Fortyeight patients whose existing drug regimes are failing will receive either PA-457 or a placebo in addition to their standard drugs. There are plans to try the drug along with new regimes tailored to individual patients, though Allaway warns that larger trials are needed and PA-457 will not reach the market until 2009 at the earliest.

Breast Cancer Patients Benefit From Yoga

Breast cancer patients who do yoga tend to enjoy better health, less fatigue and experience less daytime sleepiness - this applies to women who are undergoing radiotherapy for their breast cancer, say scientists from the University of Texas, M.D. Anderson Cancer Center, USA. Lorenzo Cohen, study leader, said even a short yoga program - including meditation, relaxation, breathing exercises, stretching, imagery and physical movements - can be very useful at reducing the side effects that come with breast cancer treatment.

The study looked at 61 women who were undergoing a six-week radiotherapy course after breast cancer surgery. Half of them attended a twice-weekly yoga class, the other half didn't. At the end of the courses - radiotherapy and yoga courses - they had to fill in a questionnaire.

The questionnaire asked how well they coped with lifting shopping bags, walking a mile, how tired they felt (fatigue), how well they felt - other questions were also asked, all related to their general well being and ability to carry out certain physical functions. Depending on how the women answered the questionnaire, points were attributed, up to a maximum of 100. The yoga group scored an average of 82 points while the non-yoga group scored 69.

An important part of yoga involves the creation of a balance in the body through the development of strength and flexibility. This is achieved mainly through performing certain poses - each pose has benefits. The poses can be done rapidly, one after the other - this creates heat in the body as a result of movement. It is also possible to perform the movements slowly, this raises stamina - the person in this case is also improving the alignment of the pose. Yoga experts may disagree on how each pose should be ideally performed.

Older Men's Sperm Risk Genetic Problems Offspring

Babies born to older men carry a higher risk of having genetic problems, says a study from the USA . A French study showed that male infertility shoots up after the age of 40. Not only does the lower quality of older men's sperm lower fertility, it also makes it more likely that babies with genetic abnormalities are born. Women of any age who become pregnant with older men also have a higher risk of miscarriage, the study found.

The US study analyzed the semen of 97 men, aged 22-80. All the men were non-smokers. The scientists tested for DNA damage, chromosomal abnormalities and gene mutations. They found that lower sperm motility correlated with DNA fragmentation. The study showed that men, as well as women, have a biological fertility clock. The difference seems to be that for women the change occurs more abruptly.

Even though older men are more likely to produce babies with genetic problems, there is not a raised risk of having a child with Down syndrome, Klinefelter syndrome, Turner syndrome, triple X syndrome, and XYY - as is the case with older women. Some older men, a small fraction, have a higher risk of fathering offspring with multiple genetic and chromosomal defects.

The researchers found that older men recruited in the Baltimore inner city area had an increased risk of fathering children with Apert syndrome. However, this was not the case with the men recruited in California. Apert syndrome is a serious disfiguring birth defect. The report suggests that socioeconomic, ethnic and/or dietary factors may also influence how age affects human sperm quality.

The Erectile Effects of Viagra

The Viagra era was launched on March 27, 1998. More than six million Americans are using the drug with an approximate overall success rate of about 75 percent. What can be done for those patients who have suboptimal results or no effect on their erectile dysfunction?

The Viagra era was launched on March 27, 1998. More than six million Americans are using the drug with an approximate overall success rate of about 75 percent. What can be done for those patients who have suboptimal results or no effect on their erectile dysfunction? I generally suggest using the 100 mg dosages since the side effect profile is the same with the 25, 50, or 100 mg dosage, and the effectiveness rate of the 100 mg dose overall is approximately 20% greater than the 50 mg dosage.

The drug works best with an empty stomach so no food should be eaten at least two hours before taking the Viagra pill. The neurological system must be intact between the brain and the penis, and sexual stimulation is necessary for the Viagra to be effective. Patients often ask what they can do if the drug is still not effective, suboptimal, or needs additional improvement? A simple non-pharmacologic way of handling this problem is to use a vacuum compression device without a constriction band.

Even in those cases in which the Viagra poorly improves erectile dysfunction the addition of a vacuum compression device brings enough blood into the penis that the veno-occlusive aspects of Viagra are working well enough to maintain sufficient erection for sexual activity and not necessitating the use of a constriction band.

Men can also use an intraurethral pellet of Muse usually in the 500 to 1000 mcg range. After Viagra and sexual stimulation the pellet is inserted into the urethra usually after voiding, moistening the plastic applicator, and massaging the urethra for approximately two to three minutes. The combined effects of the Viagra on the cyclic GMP system appear to be synergistic with the prostaglandin on the cyclic AMP system.

More commonly the Viagra is given as a supplement to injectable Prostaglandin which in these cases is not effective to establish a good enough erection for penovaginal intercourse. The Viagra sensitizes the penis to allow a more effective result when the injection is administered after the usual one to four hours of delayed stimulation.

Age Increase, Diabetes, Erectile Dysfunction

The first nationally representative study of erectile dysfunction (ED) showed the prevalence was significantly associated with increasing age and with diabetes, according to a new study conducted by Culley C. Carson, M.D., professor at the University of North Carolina, Chapel Hill. His findings will be presented at the American Urological Association Annual Scientific Meeting.

This is the first nationally representative cross-sectional study of ED among men ages 40 and older, with no upper age limit. It was designed to determine age-specific ED prevalence in black, white and Hispanic men, and to evaluate the associations between ED and other comorbidities.

The five-month study used a list-assisted, random-digit dialing design to obtain a nationally representative sample of in 134 non-Hispanic black, 491 non-Hispanic white and 195 Hispanic men. Computer-assisted telephone interviews collected non-sensitive information, such as demographics and medical history, while an automated telephone self-interview collected sensitive information on sexual habits.

The results showed that 49, 29, 14 and eight percent of men reported they were "always," "usually," "sometimes," or "never" able to keep a satisfactory erection for sexual intercourse, respectively. Those who answered "sometimes" or "never" were labeled as having ED.

Erectile dysfunction is a common problem - 22 percent of those interviewed reported having the condition," Carson said. "Although further testing is needed to more accurately determine the relationship between age, diabetes and erectile dysfunction, this study gives us a preview of what we will find."

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