Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:2.7.7.48 (transcriptase)
 9,479 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Tumor necrosis factor (TNF)-alpha has been shown to be increased in brain tissue of AIDS patients and may function as a mediator of cerebral damage. We initiated a study to determine the cellular localization and degree of protein and mRNA expression of the two specific TNF-alpha receptors (TNF-Rs), p55 and p75, in brain tissues from AIDS patients. Cerebral white matter obtained at autopsy from 13 AIDS patients, 10 unhealthy controls, and 4 healthy controls was evaluated. Double-label immunohistochemistry revealed prominent up-regulation of p55 and p75 TNF-Rs on activated macrophages and microglial cells in all AIDS patients; no increased staining was found on astrocytes. Staining was most prominent in patients with opportunistic infection of the brain and in microglial nodules of patients with HIV encephalitis. Brain tissues also showed increased expression of interleukin (IL)-1 beta, IL-6, and TNF-alpha, cytokines known to up-regulate the TNF-Rs. Increased staining for TNF-Rs was also found in patients with multiple sclerosis, chronic cerebral edema, and radiation necrosis but not in an asymptomatic HIV-positive patient without AIDS. Reverse transcriptase polymerase chain reaction performed on adjacent sections from five AIDS patients revealed up-regulation from normal for p55 in all patients and for p75 in three patients. The up-regulation of both TNF-Rs in AIDS suggests that macrophages and microglial cells may be important in amplifying the TNF-alpha response.
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PMID:Increased expression of tumor necrosis factor-alpha receptors in the brains of patients with AIDS. 854 30

In the brain of patients with AIDS, HIV-1 is localised in a productive form in mononuclear cells. One issue that still needs clarification is whether HIV is localised in cells other than those of mononuclear lineage. Gene amplification by polymerase chain reaction/in situ hybridisation (PCR-IS) could shed light on it. In this study, formalin-fixed, paraffin-embedded brain tissue from ten adult AIDS sufferers was used. Five of them showed evidence of HIV encephalitis (HIVE), five did not show any abnormality. Nested PCR revealed HIV-1 DNA in all HIVE cases and in three of the group without HIVE. HIV-1 DNA and RNA were also detected in situ in seven cases (all seven were also HIV-1 DNA positive in tube). A higher signal was located in the white than in the grey matter. HIV-1 DNA was found in microglia, macrophages, perivascular cells, multinucleated gaint cells (MGC) and in CD68-negative cells. Some of them were identified as endothelial cells, astrocytes and oligodendrocytes. Reverse transcriptase-PCR-IS was positive in macrophages, MGC, endothelial and glial cells. These results confirm infection of endothelial cells and other glial cells and give clues about the route of entry of virus into the central nervous system and the pathogenesis of the disease. This study did not give any convincing evidence supporting an infection of neurons by HIV-1.
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PMID:Detection and localisation of HIV-1 DNA and RNA in fixed adult AIDS brain by polymerase chain reaction/in situ hybridisation technique. 1054 71