909 resultados para HIV-1 reverse transcriptase


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HIV patients frequently have opportunistic oesophageal infections. We report Haemophilus ducreyi genetic material detected by polymerase chain reaction in biopsies of oesophageal lesions in three HIV-1-infected patients. This finding may be an indication of its aetiopathological role in oesophageal lesions of HIV patients.

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Loss-of-function mutations in telomerase complex genes can cause bone marrow failure, dyskeratosis congenita, and acquired aplastic anemia, both diseases that predispose to acute myeloid leukemia. Loss of telomerase function produces short telomeres, potentially resulting in chromosome recombination, end-to-end fusion, and recognition as damaged DNA. We investigated whether mutations in telomerase genes also occur in acute myeloid leukemia. We screened bone marrow samples from 133 consecutive patients with acute myeloid leukemia and 198 controls for variations in TERT and TERC genes. An additional 89 patients from a second cohort, selected based on cytogenetic status, and 528 controls were further examined for mutations. A third cohort of 372 patients and 384 controls were specifically tested for one TERT gene variant. In the first cohort, 11 patients carried missense TERT gene variants that were not present in controls (P<0.0001); in the second cohort, TERT mutations were associated with trisomy 8 and inversion 16. Mutation germ-line origin was demonstrated in 5 patients from whom other tissues were available. Analysis of all 3 cohorts (n = 594) for the most common gene variant (A1062T) indicated a prevalence 3 times higher in patients than in controls (n = 1,110; P = 0.0009). Introduction of TERT mutants into telomerase-deficient cells resulted in loss of enzymatic activity by haploinsufficiency. Inherited mutations in TERT that reduce telomerase activity are risk factors for acute myeloid leukemia. We propose that short and dysfunctional telomeres limit normal stem cell proliferation and predispose for leukemia by selection of stem cells with defective DNA damage responses that are prone to genome instability.

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Some patients with liver disease progress to cirrhosis, but the risk factors for cirrhosis development are unknown. Dyskeratosis congenita, an inherited bone marrow failure syndrome associated with mucocutaneous anomalies, pulmonary fibrosis, and cirrhosis, is caused by germline mutations of genes in the telomerase complex. We examined whether telomerase mutations also occurred in sporadic cirrhosis. In all, 134 patients with cirrhosis of common etiologies treated at the Liver Research Institute, University of Arizona, between May 2008 and July 2009, and 528 healthy subjects were screened for variation in the TERT and TERC genes by direct sequencing; an additional 1,472 controls were examined for the most common genetic variation observed in patients. Telomere length of leukocytes was measured by quantitative polymerase chain reaction. Functional effects of genetic changes were assessed by transfection of mutation-containing vectors into telomerase-deficient cell lines, and telomerase activity was measured in cell lysates. Nine of the 134 patients with cirrhosis (7%) carried a missense variant in TERT, resulting in a cumulative carrier frequency significantly higher than in controls (P = 0.0009). One patient was homozygous and eight were heterozygous. The allele frequency for the most common missense TERT variant was significantly higher in patients with cirrhosis (2.6%) than in 2,000 controls (0.7%; P = 0.0011). One additional patient carried a TERC mutation. The mean telomere length of leukocytes in patients with cirrhosis, including six mutant cases, was shorter than in age-matched controls (P = 0.0004). Conclusion: Most TERT gene variants reduced telomerase enzymatic activity in vitro. Loss-of-function telomerase gene variants associated with short telomeres are risk factors for sporadic cirrhosis. (HEPATOLOGY 2011;53:1600-1607)

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Since the discovery of RNAi technology, several functional genomic and disease therapy studies have been conducted using this technique in the field of oncology and virology. RNAi-based antiviral therapies are being studied for the treatment of retroviruses such as HIV-1. These studies include the silencing of regulatory, infectivity and structural genes. The HTLV-1 structural genes are responsible for the synthesis of proteins involved in the entry, assembly and release of particles during viral infection. To examine the possibility of silencing HTLV-1 genes gag and env by RNA interference technology, these genes were cloned into reporter plasmids. These vectors expressed the target mRNAs fused to EGFP reporter genes. Three small interference RNAs (siRNAs) corresponding to gag and three corresponding to env were designed to analyze the effect of silencing by RNAi technology. The plasmids and siRNAs were co-transfected into HEK 293 cells. The results demonstrated that the expression of the HTLV-1 gag and env genes decreased significantly in vitro. Thus, siRNAs can be used to inhibit HTLV-1 structural genes in transformed cells, which could provide a tool for clarifying the roles of HTLV-1 structural genes, as well as a therapy for this infection. (C) 2011 Elsevier B.V. All rights reserved.

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Objective: Studies carried Out to assess the effects of antiretroviral drugs (ARV) in HIV-1 infected pregnant women have demonstrated carbohydrate intolerance. Some reports also refer to the effect of disturbances in the expression of the insulin-like growth factor (IGF) system on pancreas beta-cell function in humans and IGF-2/ApaI polymorphisms have been associated with obesity and features of the metabolic syndromes. in the present study, we tested the association between IGF-2/ApaI genotype and hyperglycemia in HIV-1 infected pregnant women receiving ARV. Design: We studied IGF-2/ApaI polymorphism in 87 healthy pregnant women, 43 HIV-1 infected pregnant women taking ARV with hyperglycemia during pregnancy, and 43 HIV-1-negative pregnant women with gestational diabetes. Blood samples were obtained for DNA extraction, PCR and genotyping. Data were analyzed statistically by the Kolmogorov-Smirnov normality, ANOVA and chi-square tests. Results: There were no significant differences in genotype frequency among the three groups analyzed. Considering the HIV-1-infected pregnant women, there were no significant differences in genotype frequency between the zidovudine group and the triple antiretroviral treatment group. There were no significant differences in allele frequencies among the groups evaluated. Non-white pregnant women tended to present the GG genotypes compared to white pregnant women. Conclusion: These results contribute to a better understanding of metabolic glycemic disorders in HIV-1 infected pregnant women using ARV, showing that IGF-2/ApaI polymorphisms are not responsible as a single Causative factor of glycemic alterations. These data indicate that other variables should be studied in order to explain these glycemic abnormalities. (C) 2009 Elsevier Ltd. All rights reserved.

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Feline immunodeficiency virus (FIV) causes a slow progressive degeneration of the immune system which eventually leads to a disease comparable to acquired immune deficiency syndrome (AIDS) in humans. FIV has extensive sequence variation, a typical feature of lentiviruses. Sequence analysis showed that diversity was not evenly distributed throughout the genome, but was greatest in the envelope gene, env. The virus enters host cells via a sequential interaction, initiated by the envelope glycoprotein (env) binding the primary receptor molecule CD134 and followed by a subsequent interaction with chemokine co-receptor CXCR4. The purpose of this study was to isolate and characterize isolates of FIV from an open shelter in Sao Paulo, Brazil. The separated PBMC from 11 positive cats were co-cultured with MYA-1 cells. Full-length viral env glycoprotein genes were amplified and determined. Chimeric feline x human CD134 receptors were used to investigate the receptor utilization of 17 clones from Brazilian isolates of Fly. Analyses of the sequence present of molecular clones showed that all clones grouped within subtype B. In contrast to the virulent primary isolate FIV-GL8, expression of the first cysteine-rich domain (CRD1) of feline CD134 in the context of human CD134 was sufficient for optimal receptor function for all Brazilian FIV isolates tested. (C) 2011 Elsevier B.V. All rights reserved.

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A total of 57 captive neotropical felids (one Leopardus geoffroyi, 14 Leopardus pardalis, 17 Leopardus wiedii, 22 Leopardus tigrinus, and three Puma yagouaroundi) from the Itaipu Binacional Wildlife Research Center (Refugio Bela Vista, Southern Brazil) were anesthetized for blood collection. Feces samples were available for 44 animals, including one L. geoffroyi, eight L. pardalis, 14 L. wiedii, 20 L. tigrinus, and one P. yagouaroundi. Total DNA and RNA were extracted from blood and feces, respectively, using commercial kits. Blood DNA samples were evaluated by polymerase chain reaction (PCR) for feline leukemia virus (FeLV) proviral DNA, whereas reverse transcriptase-PCR was run on fecal samples for detection of coronavirus RNA. None of the samples were positive for coronaviruses. A male L. pardalis and a female L. tigrinus were positive for FeLV proviral DNA, and identities of PCR products were confirmed by sequencing. This is the first evidence of FeLV proviral DNA in these species in Southern Brazil.

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Avian metapneumovirus (AMPV) causes turkey rhinotracheitis and is associated with swollen head syndrome in chickens, which is usually accompanied by secondary infections that increase mortality. AMPVs circulating in Brazilian vaccinated and nonvaccinated commercial chicken and turkey farms were detected using a universal reverse transcriptase (RT)-PCR assay that can detect the four recognized subtypes of AMPV. The AMPV status of 228 farms with respiratory and reproductive disturbances was investigated. AMPV was detected in broiler, hen, breeder, and turkey farms from six different geographic regions of Brazil. The detected viruses were subtyped using a nested RT-PCR assay and sequence analysis of the G gene. Only subtypes A and B were detected in both vaccinated and nonvaccinated farms. AMPV-A and AMPV-B were detected in 15 and 23 farms, respectively, while both subtypes were simultaneously found in one hen farm. Both vaccine and field viruses were detected in nonvaccinated farms. In five cases, the detected subtype was different than the vaccine subtype. Field subtype B virus was detected mainly during the final years of the survey period. These viruses showed high molecular similarity (more than 96% nucleotide similarity) among themselves and formed a unique phylogenetic group, suggesting that they may have originated from a common strain. These results demonstrate the cocirculation of subtypes A and B in Brazilian commercial farms.

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In order to verify possible association between immune reconstitution inflammatory syndrome (IRIS) and oral manifestations (OMs), we selected AIDS patients who had low CD4 count before the initiation of highly active antiretroviral therapy (HAART) and who returned three months later for therapy evaluation. The oral lesions observed three months after the initiation of HAART were evaluated and associated with the type of antiretroviral therapy (ART), CD4 count and HIV-RNA load levels (before and three months after HAART initiation). A total of 105 patients matched the selected criteria. Immune reconstitution (IR) was identified in 35.2%. Among these patients, the mean CD4 cell count rose from 105.97 to 330.29 and the mean viral load dropped from 168.005 (log 5.22) to 21.852 (log 4.33). There was no significant difference in age (P=0.78), sex (P=0.41) or previous history of ART (P=0.55) between IR and non-IR patients. In the IR group, the most common OM was. parotid enlargement (57.14%) (P=0.619), whereas in the non-IR group candidiasis (46.15%) was the most common OM. The results of our study suggest that the parotid gland enlargement found in the studied population might be an IRIS event, as it was found in patients with IR three months after the initiation of HAART.