Squamous cell carcinoma of the esophagus (SCCE) is diagnosed late and carries a poor prognosis. Biomarkers such as p53 protein expression may be present in the esophageal mucosa long before esophageal symptoms or lesions appear and may point toward early diagnosis. Asymptomatic subjects at high risk for SCEE (consumption of more than 80 g of ethanol and 10 cigarettes/day for at least 10 years) underwent upper gastrointestinal endoscopy with biopsies of the esophageal mucosa, and expression of p53 protein was compared with conventional histologic findings. In 182 subjects studied, p53 protein was expressed in a stepwise fashion according to the severity of the histologic findings: normal mucosa (12/103 or 11.7%), mild chronic esophagitis (6/43 or 14%), moderate chronic esophagitis (4/18 or 22.2%), severe chronic esophagitis (1/3 or 33.3%), low-grade dysplasia (4/11 or 36.4%), high-grade dysplasia (2/2 or 100%), and squamous cell carcinoma (2/2 or 100%) (P=0.00025). The odds ratio and confidence intervals were calculated by logistic regression, with multivariate adjustment for potentially confounding variables. The risk for p53 expression was twofold for moderate and severe chronic esophagitis and 10-fold for dysplasia and cancer (P=0.001). p53 protein was expressed not only in cancerous lesions, high-grade and low-grade dysplasia, as expected, but also in mucosa considered normal or with chronic esophagitis using conventional histology. Smokers and alcohol drinkers with normal mucosa or chronic esophagitis that express p53 protein may represent an unrecognized subgroup of individuals that may benefit from surveillance. Follow-up studies of these asymptomatic subjects and molecular analysis of the p53 gene are needed to clarify this point.

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In the village of Cavunge, located in a dry tropical, semiarid rural region of the state of Bahia, Brazil, a sentinel study on viral hepatitis is underway. We report on the first part of the study. The

A sentinel study on viral hepatitis is currently being carried out in the village of Cavunge in a semiarid rural region of the state of Bahia, northeastern Brazil. This study has identified individuals in whom anti-HBc IgG was the only serological marker for hepatitis B virus (HBV). This serological pattern may constitute evidence of occult HBV infection. This study Investigated the possibility of occult hepatitis B virus infection in individuals in a rural community who tested positive for anti-HBc IgG alone. A cross-sectional population-based study. ELISA III was performed on serum samples to test for serological viral markers, and ultrasensitive PCR (US-PCR) was used to assess viremia. Among the 1,536 serum samples, 3.6% (n=55) were positive for anti-HBc alone. Four years after this first serological survey, 31 of those 55 individuals (56.3%) were retested, and 11 (35.5%) remained anti-HBc positive alone. Two of these 31 (6.5%) were HBV-DNA positive based on US-PCR, with normal aminotransferase levels in both cases. Cases of occult hepatitis B infection were identified in this semiarid rural community of northeastern Brazil, where endemicity of HBV is moderate. Key-Words: Anti-HBc alone, hepatitis B virus, occult hepatitis B, ultrasensitive PCR.Approximately 400 million people worldwide are chronic hepatitis B carriers. Despite vaccination, serological tests performed in hemotherapy services, and programs for the prevention of sexually transmitted infections, the number of hepatitis B virus (HBV)-infected individuals remains high, with prevalence ranging from 0.1% to 20% [1].The serological marker most widely used to detect exposure to HBV is HBcAg IgG; however, this marker is unable to define the status of the HBV carrier [2]. In individuals in whom antibody against the core protein (anti-HBc IgG) is the only positive marker, there are various possible explanations for false-positive test results, including patients with past, resolved infection, in whom the antibody against hepatitis B surface antigen (anti-HBs) is not present, occult HBV infection due to mutation of the S gene, or very low viral replication [3]. In this last hypothesis, analysis for HBV-DNA is considered the most sensitive diagnostic method [4].Clearance of hepatitis B surface antigen (HBsAg) generally indicates seroconversion to anti-HBs and consequent remission of HBV infection [5]. However, several researchers have shown that seroconversion to anti-HBs is not necessarily indicative of virological cure. In this case, an occult, silent or latent hepatitis B infection may be characterized by presence of viral DNA alone, while the patient tests negative for HBsAg or anti-HBc [6]. A clear example is the diagnosis of this infection in patients with chronic hepatitis of undefined etiology (cryptogenic hepatitis), comorbid hepatitis C virus (HCV), HIV carriers, patients with chronic renal failure or patients with hepatocellular carcinoma [7,8]. There are also case reports of hepatitis B transmission following blood transfusion or organ donation...

ResumoDescrevemos uma atividade realizada no âmbito do Programa de Pré-iniciação Científica da USP, onde dois alunos do Ensino Médio (CM e DMS) frequentaram durante um ano as instalações do Departamento de Astronomia do IAG, na USP, e lá desenvolveram um projeto científico de busca de sósias da galáxia Via Láctea na base de dados do Sloan Digital Sky Survey, sob supervisão de um professor (LSJ) e com o apoio de um aluno de doutoramento (WAS). Este artigo descreve o projeto e os resultados obtidos. Palavras-chave: Astronomia; ensino de ciências; métodos computacionais. AbstractWe describe an activity realized within the Programa de Préiniciação Científica da USP, where two students of a secondary school (CM and DMS) visited during one year the Astronomy Department of IAG, USP, to develop a scientific project looking + "Doubles" of the Milky Way galaxy * Recebido: dezembro de 2009. Aceito: dezembro de 2009.