HIV causes dementia by inhibiting neurogenesis

A significant proportion of people with HIV/ AIDS develop neurological symptoms, such as impaired co-ordination, personality changes, deficits in learning and memory, and mania and depression.

HIV-associated dementia is difficult to treat; although highly active anti-retroviral therapy (HAART) has led to improved prognoses for patients, these drugs do not effectively penetrate the blood brain barrier. So, the brain can act as a “silent reservoir” for HIV, which can therefore cause lasting and irreparable damage.

Exactly how HIV causes dementia was unknown. But a new study by researchers from the University of California, San Diego at La Jolla, now shows that, as well as causing the death of neurons, the virus also inhibits formation of new cells of new brain cells involved in learning and memory. So, as well as damaging the brain, the AIDS virus prevents the organ from repairing itself.

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Researchers resurrect 8 million-year-old bacteria


From the BBC:

Microbes locked in Antarctic ice for as much as eight million years have been “resuscitated” in a laboratory.

Researchers melted five samples of ice from the debris-covered glaciers of Antarctica which range in age from 100,000 years to eight million years.

When given nutrients and warmth, the microbes resumed their activity – although younger microorganisms grew more successfully than the older ones.

According to the news story, the paper is published in the Proceedings of the National Academy of Sciences, but I couldn’t find it at the time of writing.

Update: the full text of the paper is now available.