Model explains why HIV prevention dosing differs by sex

A mathematical model developed by NIH grantees predicts that women must take the antiretroviral medication Truvada daily to prevent HIV infection via vaginal sex, whereas just two doses per week can protect men from HIV infection via anal sex.

This finding helps explain why two large clinical trials testing HIV pre-exposure prophylaxis, or PrEP, in women failed to show efficacy. Participants in the VOICE and FEM-PrEP trials of Truvada and tenofovir (another antiretroviral) for HIV prevention were counseled to take one of the medications daily. 

However, because they actually took the antiretroviral only about 29 percent of the time in VOICE and about 36 percent of the time in FEM-PrEP, the PrEP strategy did not work.

Angela D. M. Kashuba, Pharm.D., of the University of North Carolina, and colleagues determined what intracellular ratios of active tenofovir and emtricitabine, the drugs that compose Truvada, to the DNA molecules with which they compete are necessary to prevent HIV replication. 

Next, using data from an early clinical trial in women, the researchers created a mathematical model that predicts these ratios in vaginal, cervical and rectal tissues given standard doses of medication taken 2 to 7 days per week. 

Then, the scientists calculated the percentage of a study population that would achieve the effective drug-to-DNA-molecule ratio by taking tenofovir or Truvada at each dosing frequency.

Source: NIH/National Institute of Allergy and Infectious Diseases

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Публикувана от rosen -четвъртък, 30 октомври 2014 - 11:19:16изглед за печат

Largest ever dataset of individual deaths in Africa, SE Asia reveals changing health

More than 110,000 individual deaths and their causes across 13 countries (including Ghana, South Africa, Kenya, Bangladesh and Vietnam) are contained in the new INDEPTH dataset.

The data, collected by hundreds of researchers over two decades, are the first meaningful community-based information about cause of death in countries where individual deaths are not recorded automatically by national governments.

The INDEPTH cause of death findings are published in a special issue of the journal Global Health Action, which is fully open access. There are six multisite papers dealing with specific causes of death: HIV/AIDS, malaria, pregnancy-related factors, external causes (including accidental death and suicide), adult non-communicable diseases and childhood illness. 

Other papers describe methods, and many sites have contributed papers with local details. The project has been substantially funded by the Wellcome Trust.

The data were collected in 22 sites, each containing around 100,000 people. Each death was recorded by a researcher in the field who conducted a standardised verbal autopsy, a structured interview with a family member of the deceased. Data were processed by computer to establish likely causes of death.

Source: Wellcome Trust

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Публикувана от rosen -сряда, 29 октомври 2014 - 11:12:57изглед за печат

Can social media help stop the spread of HIV?

In addition to providing other potential benefits to public health, all of those tweets and Facebook posts could help curb the spread of HIV.

Although public health researchers have focused early applications of social media on reliably monitoring the spread of diseases such as the flu, Sean Young of the Center for Digital Behavior at the University of California, Los Angeles, writes in an October 29th article in the Cell Press journal Trends in Microbiologyof a future in which social media might predict and even change biomedical outcomes.

"We know that mining social media will have huge potential benefits for many areas of medicine in the future, but we're still in the early stages of testing how powerful these technologies will be," Young said.

With the right tools in place, he says, social media offers a rich source of psychological and health-related data generated in an environment in which people are often willing to share freely.

Source: Cell Press

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Публикувана от rosen -сряда, 29 октомври 2014 - 11:04:36изглед за печат

New dent in HIV-1's armor: promising target for HIV/AIDS treatment

Like a slumbering dragon, HIV can lay dormant in a person's cells for years, evading medical treatments only to wake up and strike at a later time, quickly replicating itself and destroying the immune system.

Scientists at the Salk Institute have uncovered a new protein that participates in active HIV replication, as detailed in the latest issue of Genes & Development. The new protein, called Ssu72, is part of a switch used to awaken HIV-1 (the most common type of HIV) from its slumber.

More than 35 million people worldwide are living with HIV and about a million people die a year due to the disease, according to the World Health Organization. There is no cure, and while regular medication makes the disease manageable, treatment can have severe side effects, is not readily available to everyone and requires a regiment that can be challenging for patients to adhere to.

The team began by identifying a list of 50 or so proteins that interact with a well-known protein HIV creates called Tat.

"The virus cannot live without Tat," says Katherine Jones, Salk professor in the Regulatory Biology Laboratory and senior author of the study.

Source: Salk Institute for Biological Studies

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Публикувана от rosen -петък, 24 октомври 2014 - 09:35:21изглед за печат

САЩ лицензира първата комбинирана таблетка за безинтерфероново лечение на хепатит С - Harvoni

На 10 октомври 2014 г. Американската агенция за храните и лекарствата издаде разрешение за употреба на медкамента Harvoni (ledipasvir 90 мг/sofosbuvir 400 мг) – първата комбинирана таблетка за еднократен дневен перорален прием за лечение на хроничен хепатит С (HCV) при възрастни, инфектирани с генотип 1 на вируса. 

Harvoni е комбинация от ledipasvir - NS5A инхибитор, и sofosbuvir - нуклеотиден аналогов полимеразен NS5B инхибитор. Sofosbuvir е разрешен за употреба под търговското име Sovaldi през декември 2013 г. в САЩ и през януари тази година в Европа.

Harvoni е първата комбинирана таблетка, която получава разрешение за употреба за лечение на хроничен хепатит С генотип 1. Освен това е първата лечебна комбинация, която не изисква прием с интерферон или ribavirin – два други медикамента, използвани за лечение на хроничен хепатит С. И двата медикамента в състава на Harvoni взаимодействат с ензими, необходими за репликацията на HCV.

Ефикасността на Harvoni е установена при пациенти с HCV генотип 1, при които лечението продължава 8, 12 или 24 седмици в зависимост от предишни провеждани терапии, състояние по отношение на цирозата и изходния вирусен товар. Продължителност на лечение от 8 седмици с Harvoni може да се обмисля при терапевтично наивни пациенти без цироза с изходен вирусен товар за HCV под 6 милиона IU/mL.

В хода на трите клинични проучвания Фаза 3 (ION-1, ION-2 и ION-3) за изпитване на медикамента, Harvoni постига степен на излекуване (SVR12) от 94-99%.

Източник: Gilead Sciences

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Публикувана от rosen -сряда, 15 октомври 2014 - 09:45:48изглед за печат

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