ABSTRACT Hepatitis B virus (HBV) infection is a serious global health problem. HBV has a high viral genetic diversity, with 10 genotypes recognized. In Brazil, the Roraima State is the third in the Northern region regarding the number of hepatitis B cases. On the other hand, few data on HBV genotyping and phylogenetic analysis are available. The purpose of this study is to characterize the HBV genotypes circulating in Roraima State. Of the 113 chronic hepatitis B patients enrolled in this study, 40 were HBV-DNA positive. A fragment of 280 bp (S gene) was amplified by PCR and submitted to nucleotide sequencing. A dataset containing the viral sequences obtained in this study, plus 130 obtained from GenBank was used for genotyping by phylogenetic analysis. The HBV subgenotype distribution found was A1 (62.5%), A2 (7.5%), D2, D3, D4 (2.5%), F2a (12.5%), and F3 (10%). We characterized the genotypes and subgenotypes of HBV circulating among patients in the State of Roraima. In addition, our study shows for the first time the HBV/F3 genotype circulating in Brazil. In conclusion, our findings showed a high diversity of HBV genotypes in Roraima, which is also found in other Brazilian geographical regions.

Amostras séricas de 150 pacientes, com diagnóstico presuntivo de dengue e resultado negativo para dengue por ELISA-NS1-Antígeno do kit Platelia™ (NS1-Ag), foram analisadas pela técnica de TaqMan Transcrição Reversa seguida da Reação em Cadeia da Polimerase em Tempo Real (qRT-PCR). As amostras positivas por qRT-PCR, foram submetidas a identificação dos sorotipos por RT-Hemi nested-PCR e a ensaio imunocromatográfico para detecção qualitativa dos anticorpos IgG e IgM. A técnica molecular apresentou como resultado 33 (22%) amostras positivas entre as 150 negativas pela detecção do NS1-Ag, destas o 72% foram coletadas até o segundo dia de início dos sintomas da doença, período de maior sensibilidade para pesquisas de NS1-Ag. A maioria dos casos não evidenciou infecção secundária. Dessas amostras, 28 foram satisfatoriamente sorotipadas sendo 75% de DENV-4, 14% de DENV-2, 7% de DENV-3 e 4% de DENV-1. Os resultados reafirmam a situação hiperendêmica do Estado de Roraima e sugerem baixa sensibilidade do NS1 test, especialmente quando o sorotipo predominante é DENV-4. Sugerimos assim, que a comunidade médica deve ser alertada no sentido de ser cautelosa com resultados de NS1-Ag negativo, principalmente quando sintomas clínicos e outros resultados laboratoriais sejam indicativos de provável infecção por dengue.

Serum samples from 150 NS1-negative (Platelia ELISA) patients presumptively diagnosed with dengue were analyzed by the TaqMan probed real-time reverse transcription PCR (TaqMan qRT-PCR) method. The qRT-PCR positive samples were tested for serotype by semi-nested RT-PCR and a qualitative immunochromatographic assay for IgG and IgM. Molecular detection methods showed 33 (22%) positive samples out of 150 NS1-antigen negative samples. Of these, 72% were collected up to day 2 after the onset of symptoms, when diagnostic sensitivity of NS1-antigen test assays is significantly enhanced. Most of the cases were not characterized as secondary infection. Twenty-eight samples were successfully serotyped, 75% of which for DENV-4, 14% for DENV-2, 7% for DENV-3 and 4% for DENV-1. These findings reaffirm the hyperendemic situation of the state of Roraima and suggest a lower sensitivity of the NS1 test, mainly when DENV-4 is the predominant serotype. Health care providers should therefore be aware of samples tested negative by NS1 antigen assays, especially when clinical symptoms and other laboratory data results show evidence of dengue infection.

Background: The identification of groups at high risk is fundamental to determine preventive strategies for skin cancer. Destructive reactive oxygen species produced by UVA or chemical carcinogens are metabolized by a series of enzymes. Polymorphisms of genes encoding for these enzymes may produce defective proteins with a diminished ability to detoxify a wide range of carcinogens. Aims: To ascertain the influence and potential interactions of several polymorphisms of genes encoding four important antioxidant GST enzymes in the susceptibility to cancer among Brazilians. Material and methods: We compared the genotypes of Glutathione S-Transferase mu, theta, pi and omega (GSTM1, GSTT1, GSTP1 and GSTO2) in a group of 102 patients with skin lesions and 124 controls. Results: Patients with Basal Cell Skin Carcinoma (BCC) presented the combined GSTM1-GSTT1+ genotype more frequently (49.1%) than controls (29.8%) (Fisher test; p =0.04), conferring a 2.273 (Odds Ratio; 95% CI =1.199-4.308) higher risk for BCC. We were not able to find any other association between genotypes or between any genotype and the patients' clinical features. Conclusions: The GST profile may help identify Brazilian individuals at higher risk for BCC

Antecedentes: La identificación de grupos en riesgo elevado es fundamental en la determinación de las estrategias preventivas para el cáncer de la piel, el maligno humano más común. Las especies reactivas destructivas del oxígeno producidas por UVA o los agentes carcinógenos químicos son metabolizadas por una serie de enzimas. Los polimorfismos de los genes que codifican para estas enzimas pueden producir las enzimas defectuosas con una capacidad disminuida de desintoxicar una amplia gama de agentes carcinógenos. Objetivo: Este estudio fue diseñado para comprobar las interacciones de la influencia y del potencial de varios polimorfismos de los genes que codificaban 4 enzimas importantes del antioxidante GST en la susceptibilidad al cáncer entre brasileños. Métodos: Comparamos los genotipos del mu del S-Transferase del Glutathione, de la theta, de pi y de Omega (GSTM1, GSTT1, GSTP1 y GSTO2) en un grupo de 102 lesiones de piel y de 124 controles. Resultados: Los pacientes con el carcinoma basocelular (BCC) presentaron el genotipo combinado de GSTM1-GSTT1+ más frecuente (49,1%) que los controles (29,8%) (Fisher test; p =0,04), confiriendo 2.273 (Odds Ratio 95% CI =1.199-4.308) un riesgo más alto para BCC. No encontramos ninguna otra asociación entre los genotipos o entre ningún genotipo y características clínicas de los pacientes. Conclusiones: Sugerimos que el perfil de GST pueda ayudar a identificar a individuos brasileños en un riesgo más alto para BCC

Background: p53 is a nuclear protein that exerts an important role in the negative control of cellular proliferation, as well as in masterminding signaling cascades important in DNA repair and/or apoptosis. Mutations of p53 have been reported with high frequency in many cancer types and are highly prevalent in poorly differentiated and undifferentiated thyroid carcinomas, but they are not found in benign tumors and are infrequent in well-differentiated cancer. Most mutations are located in exons 5-8 of the gene. Recently, a germline mutation in the seldom investigated exon 10, on codon 337 of p53 was described in Brazilian children who had adrenocortical tumors. Aim: To study codon 337 of exon 10 of p53 mutation in thyroid tumors. Material and methods: Seventy four thyroid tumors were studied (5 follicular carcinomas including 3 widely invasive, 22 papillary carcinomas including 6 tall cell variants, 11 follicular adenomas, 1 medullary carcinoma and 35 benign goiters). DNA was extracted from a central part of all tumors and contralateral normal thyroid tissue samples or blood from 38 of these patients. The products of PCR for exon 10 of p53 were examined by single strand conformation polymorphism (SSCP) analysis. We sequenced 2 samples suspected of presenting aberrant migrating bands and 3 additional PCR products from tumor samples with normal SSCP patterns but all were wild type. Results: In all samples studied, a wild type sequence was found. Conclusions: Exon 10 of p53 gene does not present mutations in thyroid tumors, suggesting that this mutation is specific of adrenocortical cancers. (Rev Méd Chile 2004; 132: 1513-6)