AIDS care vaginal gel to prevent HIV infection and Female sex behaviour determines the quality and quantity of sperm
By Live Dr - Thu Apr 02, 7:53 am
Vaginal gel prevents HIV infection among women
in clinical trials
A vaginal gel to preventinfection has shown encouraging results in a clinical trial conducted on women in Africa and the US.
Findings of the recently concluded study, funded by the of Allergy and (NIAID), part of the NIH, were presented at the Conference on Retroviruses and Opportunistic Infections underway in Montreal.
Investigators found microbicide gel PRO 2000 safe and approximately 30 percent effective, as gel, foam or cream, which when applied to vaginal or anal orifice, may prevent male-to-female sexual transmission ofinfection.
“Although more data are needed to conclusively determine whether PRO 2000 protects women frominfection, the results of this study are encouraging,” said NIAID director Anthony S. Fauci.
The Phase II/IIb clinical trial, which enrolled more than 3,000 women, is NIH’s first large clinical study of a microbicide.
“The study, while not conclusive, provides a glimmer of hope to millions of women at risk for, especially young women in Africa,” added lead investigator Salim S.A. Karim, from the Centre for the AIDS Program of Research in South Africa.
“It provides the first signal that a microbicide gel may be able to protect women frominfection,” he said.
Currently, women make up half of all people worldwide living with. In sub-Saharan Africa, women represent nearly 60 percent of adults living with , and in several southern African countries young women are at least three times more likely to be -positive than young men, said an NIAID release.
A separate clinical study sponsored by the Medical Research Council (MRC) and the Department for International Development of Britain that is currently testing PRO 2000 (0.5 percent dose) in preventinginfection among women in Africa could provide further insight into the microbicide’s effectiveness.
That Phase III study involving nearly 9,400 women is set to conclude in August 2009.
Source: Indo-Asian News Service
Female promiscuity raises quality of sperm in her
Female behaviour determines the quality and quantity of sperm of her mating partner, says a new Canadian study.
If she is promiscuous, she can trigger changes in the quality and quantity of sperm of a male as he has to compete with other males to impregnate her.
Only if he can produce better, larger and faster sperm than others does he stand a chance of impregnating her, says the study on fish byat Hamilton near here.
The study says the idea that sperm would evolve to become more competitive when males compete for fertilisation seems obvious, but there has been little proof of this till date.
Its conclusions are based on the competition for reproduction among species of African fish that influences the sperm of suitors.
These fish exhibit diverse mating behaviours, ranging from strict monogamy to mating with many males in quick succession, a university statement said.
, study author and associate professor in the department of psychology, neuroscience and behaviour at the university, said: “In promiscuous species, we found that males produced larger and faster sperm than in closely related species that were monogamous.
“This research offers some of the first evidence that sperm has evolved to become more competitive in response to females mating with multiple males.”
Balshine said female promiscuity becomes a challenge for males when they have to compete with rival suitors to impregnate her.
As part of their study, researchers collected males from 29 closely related species found off the Zambian shores of. They examined the relationship between promiscuity and sperm quality and then used computer simulations to assess how sperm evolved in these fish.
“Our analysis confirmed that sperm became more competitive only after a species shifted their mating behaviours to become more promiscuous,” the statement quoted study leader John Fitzpatrick as saying.
He said: “The first step in producing more competitive sperm was by influencing how much energy the sperm can produce. Just like a mechanic could make a car drive faster by installing a better engine, evolution appears to act first on the engine that drives sperm movement.”
The study has been published in the Proceedings of the National Academy of Sciences of the US.
Source: Indo-Asian News Service