News (Updated
September 7, 2008)
[Home]
[Previous
news]
By Julie Steenhuysen
CHICAGO (Reuters) - The AIDS virus is especially hard to fight because few people develop antibodies to neutralize it, but U.S. researchers said on Thursday they have found an immunity gene that may offer a new way to fight back.
They said the gene Apobec3 helps mice develop antibodies against an HIV-like virus, and they think the same gene in humans could lead to a potent vaccine against the human immunodeficiency virus or HIV.
"This gene is central to HIV biology," Dr. Warner Greene of the Gladstone Institutes at the University of California, San Francisco, said in a telephone interview.
So far, efforts to make a vaccine against HIV have failed.
In humans, HIV devotes one of its 9 genes to disabling Apobec3 proteins, which may help explain why people with HIV rarely make antibodies against the virus, he said.
HIV is a retrovirus, which means it copies bits of its own genetic code into the DNA of the host.
"If we could prevent HIV from destroying this key pivotal host factor, we might allow HIV-infected patients to develop neutralizing antibodies like they do in mice," he said.
"It's a translation from mice to men. That's the challenge now," said Greene, whose study appears in the journal Science.
Green's lab and others have been hunting for the gene in mice that allows them to fight off the Friend virus, a retrovirus similar to HIV.
Working with a team at the National Institute of Allergy and Infectious Diseases, the researchers conducted a series of experiments in which they genetically engineered mice to lack the Apobec3 gene. "Sure enough, when we knocked out the Apobec3 gene, they lost their ability to recover from Friend virus infection," Greene said.
He said the discovery of Apobec3's role in retroviral immunity is exciting because genes in this region are active in people who resist HIV infection, suggesting they are making effective antibodies against the virus.
"Blocking this degradation of Apobec3 is probably the most promising new drug target in HIV biology," Greene said.
Antibodies are key to warding off viral infections, and most vaccines against viral diseases stimulate the body to make antibodies against the target virus.
Greene said efforts at developing an HIV vaccine have largely focused on building up a kind of immune cell called a T-cell to attack the virus.
"Those types of approaches are not proving adequate. We are desperately seeking better approaches to creating neutralizing antibodies," he said, adding, "Maybe this will help us."
The AIDS virus infects an estimated 33 million people globally and has killed about 25 million since the pandemic started in the 1980s.
There is no cure but drugs can suppress the virus and allow patients to lead a near-normal life. Without treatment, the virus destroys the immune system, leaving patients susceptible to infections and cancer.
(Editing by Maggie Fox and Todd Eastham)
NEW YORK (Reuters Health) - Sexual activity other than intercourse carries some risk of sexually transmitted disease, and doctors should make sure their patients understand that, according to the American College of Obstetricians and Gynecologists (ACOG).
Many people may engage in "noncoital" sexual activities such as oral sex, mutual masturbation and anal sex to prevent pregnancy and cut the risk of STDs. However, all of these sex acts come with some degree of STD risk, and it's still important for people to protect themselves, according to an ACOG expert committee.
"Most people, including adolescents, are unlikely to use condoms during oral sex, which places them at risk for acquiring an STD," Dr. Richard Guido, one of the report authors, said in an ACOG statement. "This unlikelihood is partly because of a greater perceived safety compared with intercourse."
Writing in the journal Obstetrics & Gynecology, the panel advises doctors to ask patients -- adults and teenagers -- about all of their sexual activities, and to counsel them on how to reduce their STD risks. Although this "is a sensitive issue to address for both patients and physicians, it's important to discuss sexuality frankly and without judgment so that we can help our patients fully protect themselves against STDs," Guido added.
While oral sex is generally safer than vaginal or anal sex, the ACOG committee notes, it is not without risk. The viruses that cause genital herpes, genital warts and hepatitis can all be transmitted through oral sex. The same is true of the bacterial STDs syphilis, gonorrhea and chlamydia.
When it comes to HIV transmission, receptive anal sex carries the highest risk, followed by receptive vaginal sex, according to ACOG. However, there have been cases of HIV linked to oral sex.
"Noncoital sexual activity is not necessarily 'safe sex'," Guido and his colleagues write in the report.
They advise "correct and consistent" condom use for all types of sexual activity, but especially vaginal and anal sex. Staying in a mutually monogamous relationship, and getting tested for STDs before starting a new relationship, are among the other ways to curb STD transmission. Another precaution, the committee notes, is to clean sex toys between uses.
It's recommended that all sexually active women age 25 or younger be screened for chlamydia once a year, while all sexually active teenagers should be screened for gonorrhea. Other screening tests are done based on individuals' STD risk factors or any symptoms they may have.
The ACOG committee points out that lesbian women should be screened on the same basis as heterosexual women.
"Most lesbians have been sexually active with men at some point," Guido said. "Even without this sexual history, there are some STDs that can be transmitted between two women during sexual activity."
SOURCE: Obstetrics & Gynecology, September 2008.
03 Sep 2008 20:22:50 GMT
A health ministry spokesman
said on Wednesday the patent request for the drug Tenofovir had been rejected,
confirming a statement from the patent office announcing the decision on grounds
that it lacked technological inventiveness.
The ministry said in April
the drug, used by 31,300 patients in
No one at
The medical group Doctors
Without Borders said the decision could boost access to HIV/AIDS medicine in
"Securing wider access
to TDF (Tenofovir) is absolutely crucial," Tido von Schoen-Angerer of the
group's Access Campaign, said in a statement.
"In the past,
The group said an
Indian-made generic version of Tenofovir approved by the World Health
Organization cost $158 per person per year, compared to $1,387 charged by Gilead
in
After climbing in the
1990s,
In 2007,
01 Sep 2008 15:27:43 GMT
Source: Reuters
By Laura MacInnis
GENEVA, Sept 1 (Reuters) -
African health workers need more training and better tools to circumcise men and
boys safely for HIV prevention, according to a World Health Organisation (WHO)
study chronicling "shocking" rates of complications.
As many as 35 percent of
males circumcised by traditional practitioners in Kenya's Bungoma district
suffered complications such as bleeding, infection, excessive pain and erectile
dysfunction from the procedure, the WHO researchers found.
"Other common adverse
effects reported were pain upon urination, incomplete circumcision requiring
recircumcision, and laceration," they wrote, estimating 6 percent of
patients had life-long problems as a result.
Although male circumcision
is universally practised in Bungoma, the study said many clinicians there lacked
sharp and clean instruments and few were formally trained. Even in public
clinics, the complication rate was 18 percent.
The findings, published on
Monday in the WHO Bulletin, raised questions about whether the availability of
male circumcision should be extended quickly as part of a strategy to fight HIV
backed by the WHO and its sister U.N. agency UNAIDS.
"Extensive training
and resources will be necessary to build the capacity of health facilities in
sub-Saharan
"Our results showing
35 percent of traditional circumcisions resulting in adverse events, many of
them serious and permanent, should also serve as an alarm to ministries of
health and the international health community that focus cannot only be on areas
where circumcision prevalence is low."
Studies have shown male
circumcision could be 70 percent effective in protecting men against HIV
infection.
Africa is the centre of the
AIDS epidemic and countries such as
The authors of the WHO
study, Kenyan expert Omar Egesah, and Robert Bailey and Stephanie Rosenberg of
the
The WHO study concluded
that health workers should be trained in sterilisation techniques, surgical
procedures, pain management, post-operative care and counselling about wound
care before male circumcision is pursued on a large scale. (Editing by Andrew
Dobbie)