This study was designed to establish the prevalence of HLA-B*5701 at HIV-1 infected individuals in Brazil. A total of 517 consecutive individuals were followed in this study from February 2009 through July 2011. The presence of HLA-B*5701 was determined by Nested-PCR with HLA-B*57 and HLA-B*5701 sequence-specific primers (PCR-SSP). The expression of HLA-B*57 was negative in the 385 (74.5%) and positive in the 103 (19.9%) of infected individuals. Among these, the expression of HLA-B5701 was positive in the 29 (5.6%) of individuals. No demographic or ethnic differences were found between HLA-B*57/HLA-B*5701 HIV-1 negative patients, with a prevalence of Caucasians (57.1%) individuals. During the period of study, 68 patients were submited to an abacavir containing regimen. The HLA-B*5701 allele was observed in 7 (10.3%) patients, with a significant incidence of Hypersensitivity reactions at 4 of them (p < 0.001). Conclusions: Although Brazilian population consists of a mixture of individuals of Caucasian, African and Native American genetic background, prevalence of HLA-B*5701 in this population is similar to the one found in pure Caucasians.

A decrease in ribosomal gene activity is an essential feature of the aging process as it was observed in Alzheimer's disease, in elderly Down's patients and in elderly healthy people. It is well known that aging is also associated with a reduction in melatonin synthesis. We studied 24 male Wistar rats cytogenetically, by using Ag-stained NOR (6 three-month-old rats underwent pinealectomy and were studied after 20 days; 6 control rats of the same age; 6 three-month-old rats underwent pinealectomy and were studied after 8 months; 6 control rats of the same age). Our results indicate that the absence of the pineal gland leads to a decrease in NOR activity. Further studies are necessary to determine if pinealectomy in rats could provide an animal model for aging.