Using polarization analysis to separate the coherent and incoherent scattering from protein samples.

Polarization analysis was used to separate experimentally the coherent and spin-incoherent nuclear static scattering functions, from a representative set of samples of interest for protein studies. This method had so far limited application in the study of amorphous materials, despite the relevance of the information that it provides. It allows, for instance, the experimental determination of the structure factor of materials containing a significant amount of hydrogen atoms, avoiding the contamination of measurements by a non-negligible incoherent background. Knowledge of the relative importance of the coherent and incoherent terms at different Q-values is also a pre-requisite for the interpretation of quasielastic neutron scattering experiments, performed at instruments in which the total dynamic scattering function is measured, such as conventional time-of-flight and backscattering spectrometers. Combining data from different instruments, it was possible to cover a wide Q-range, from the small-angle region (0.006

Should Brazilian patients with chronic hepatitis C virus infection be vaccinated against hepatitis A virus?

BACKGROUND AND AIM: Hepatitis A virus (HAV) superinfection is associated with a high risk of liver failure and death in patients with hepatitis C virus (HCV) infection. The aim of this study was to investigate the presence of serological and molecular HAV markers in a population of HCV-infected patients in order to determine a cost-effective strategy to vaccinate against HAV. METHODS: The presence of total and immunoglobulin (Ig)M anti-HAV antibodies was investigated in 399 patients (median age, 50 years; range, 4-81) referred to the Public Health Central Laboratory of Pernambuco State who tested positive for anti-HCV antibodies and HCV RNA. HAV RNA was investigated by reverse transcription-nested polymerase chain reaction in these patients. RESULTS: Three hundred and eighty-four (96%) patients were positive for anti-HAV total and negative for IgM anti-HAV antibodies (immune patients). Three patients had IgM (and total) anti-HAV antibodies, showing an acute infection, and two of them had HAV RNA detected in serum samples. HAV RNA was also found in another patient in the absence of detectable anti-HAV antibodies. By nucleotide sequencing, it was demonstrated that the HAV isolates infecting these patients belonged to subgenotype 1B. CONCLUSION: This study provides valuable new data on anti-HAV prevalence among HCV carriers in Brazil. In the present study, we found a high proportion of patients with anti-HAV positivity, indicating that anti-HAV testing of HCV-infected patients is a cost-effective strategy and should be carried out before vaccination against HAV in these patients, particularly in regions such as our geographical area with high total anti-HAV prevalence.

Prevalence of hepatitis A virus infection in Afro-Brazilian isolated communities in Central Brazil.

To investigate hepatitis A virus (HAV) infection rates among isolated African-descendant communities in Central Brazil, 947 subjects were interviewed about demographic characteristics in all 12 isolated Afro-descendant communities existing in the state of Mato Grosso do Sul, Central Brazil, between March 2002 and November 2003. Blood samples were collected and sera were tested for HAV antibodies (total and IgM anti-HAV) by enzyme-linked immunosorbent assay. The overall prevalence of HAV infection was 75.6% (95% CI: 72.7-78.3), ranging from 55.4 to 97.3%, depending on the communities studied. The prevalence of anti-HAV increased significantly with age, from 13.8% in the age 0-5 age group to 96.6% in those older than 40 years. The findings point out an intermediate endemicity of HAV infection in some Afro-Brazilian isolated communities in Central Brazil. In addition, the high proportion of susceptible young subjects could be target of future HAV vaccination programs.

Prevalence of hepatitis A virus infection in Afro-Brazilian isolated communities in Central Brazil

To investigate hepatitis A virus (HAV) infection rates among isolated African-descendant communities in Central Brazil, 947 subjects were interviewed about demographic characteristics in all 12 isolated Afro-descendant communities existing in the state of Mato Grosso do Sul, Central Brazil, between March 2002 and November 2003. Blood samples were collected and sera were tested for HAV antibodies (total and IgM anti-HAV) by enzyme-linked immunosorbent assay. The overall prevalence of HAV infection was 75.6 percent (95 percent CI: 72.7-78.3), ranging from 55.4 to 97.3 percent, depending on the communities studied. The prevalence of anti-HAV increased significantly with age, from 13.8 percent in the age 0-5 age group to 96.6 percent in those older than 40 years. The findings point out an intermediate endemicity of HAV infection in some Afro-Brazilian isolated communities in Central Brazil. In addition, the high proportion of susceptible young subjects could be target of future HAV vaccination programs.

Genetic analysis of hepatitis A virus isolates from Brazil.

A limited number of hepatitis A virus (HAV) isolates from South America have been characterised at the genomic level. IgM anti-HAV positive serum samples collected from patients with hepatitis A living in the five geographical regions of Brazil (North, Northeast, Central, South, and Southeast) were used to obtain HAV isolates and determine their genetic relatedness. Of the 232 case isolates, sequence data were obtained from the VP1/2A junction region of the HAV genome. All isolates were classified in genotype I; 231 belonged to subgenotype IA, and one to subgenotype IB. HAV isolates from four States formed distinct clusters of highly related sequences. However, isolates from other states did not cluster and the sequences from those states were intermingled with sequences found in the other states. The amino acid sequences of all but two isolates showed a Leu --> Ile substitution at position 42 in the 2A protein. This substitution appeared to be a characteristic geographic fingerprint of HAV sequences within Brazil.

Mixed infection of a child care provider with hepatitis A virus isolates from subgenotypes IA and IB revealed by heteroduplex mobility assay.

Phylogenetic analysis based on a 168 base segment encompassing the putative VP1/2A junction of the hepatitis A virus (HAV) genome has enabled the classification of HAV isolates into seven genotypes (I-VII). Genotype I, which includes the vast majority of the human HAV isolates, has been divided further into subgenotypes IA and IB. An heteroduplex mobility assay was designed with amplification products from the VP1/2A junction region, and used as a genotyping method able to discriminate HAV isolates belonging to IA, IB and non-I genotypes. The method was used to successfully genotype 48 samples (16 IA and 32 IB). However, one HAV RNA positive serum sample (AUX-23), collected from a 15 year old female employed at a child care center located in Rio de Janeiro, Brazil, showed an unusual pattern. PCR products from sample AUX-23 gave rise to heteroduplex bands when mixed with IA products as well as with IB products, suggesting the presence of HAV isolates from both subgenotypes in the serum. PCR products from sample AUX-23 were then cloned and 20 clones were analyzed by heteroduplex mobility assay. Eleven were subgenotype IA and 9 were IB. Three clones of each subgenotype were then sequenced to confirm the results. These data constitute the first report of mixed infection of a single individual with different HAV isolates.

Hepatitis B virus transmission in Brazilian hemodialysis units: serological and molecular follow-up.

A serological and molecular study of hepatitis B virus (HBV) infection was carried out in dialysis units in Central Brazil. Between 1995 and 1999, serum samples from all HBsAg-positive hemodialysis patients (n = 43) were tested for HBeAg/anti-HBe and subtyping by monoclonal ELISA. HBV DNA was detected by PCR and positive samples were genotyped by restriction fragment polymorphism pattern (RFLP) methodology. TheHBsAg prevalence declined in this population during the survey period (12-5.8%). HBeAg and anti-HBe were detected in 23 (53.5%) and 18 (41.9%) sera, respectively. Thirty-six samples could be HBsAg subtyped: 21 were subtype ayw(3), 14 belonged to adw(2) and one was identified as adw(4). HBV DNA was present in 30 serum samples. Of these, 20 (66.7%) were genotype D, 9 (30%) genotype A, and 1 (3.3%) genotype F. In addition, the RFLP pattern could be determined in samples from 18/20 genotype D patients: D3 (10 strains), D7 (7 strains) and D4 (1 strain); from 8/9 genotype A patients: A1 (6 strains) and A3 (2 strains); and from the patient infected with genotype F: F1. Patterns D3 and D7 were associated closely with HBV infection in the two largest hemodialysis units studied. These findings confirm the value of the RFLP method as an effective molecular epidemiological tool for elucidating HBV transmission in hemodialysis units.

Characterization of hepatitis A virus isolates from subgenotypes IA and IB in Rio de Janeiro, Brazil.

Hepatitis A virus (HAV) isolates from around the world have been classified into seven genotypes (I-VII). Most human strains belong to genotype I, which has been divided into two subgenotypes, A and B. South America has provided a small number of strains studied at the genome level. In the present study, IgM anti-HAV antibodies were detected in 116 out of 250 (46%) serum samples collected from consecutive patients with acute hepatitis referred to the Brazilian Reference Center for Viral Hepatitis, Rio de Janeiro. Viral RNA were extracted from all 250 samples and submitted to a reverse transcription-polymerase chain reaction (RT-PCR) assay designed to amplify a genome segment in the VP1/2A junction region. HAV RNA was detected in 54/116 (47%) and 17/134 (13%) IgM anti-HAV-positive and -negative sera, respectively. In addition, HAV RNA was detected in 17/35 (49%) IgM anti-HAV-positive sera that had been collected at a day care center where cases of acute hepatitis were being observed for 3 months. Nucleotide sequences (168 bp) of PCR products were determined for 30 HAV isolates. Phylogenetic analysis showed that 21 belonged to subgenotype IB, while 9 were of subgenotype IA. Interestingly, a concomitant circulation of isolates from subgenotypes IA and IB was observed in the day care center.

Prevalência e fatores associados a marcadores do vírus da hepatite B em população rural do Brasil central / Prevalence of and factors associated with hepatitis B virus markers in a rural population in central Brazil

Objective. To carry out a survey of hepatitis B virus seroepidemiology in a municipality in central Brazil, on the border of two large ecosystems, the cerrado (savanna) and the Amazon River basin. Methods. The municipality studied, Nova Mutum, is located in the north central portion of the Brazilian state of Mato Grosso. The study sample of 754 individuals included persons from families, selected at random, who were living in the municipality's urban center as well as all the individuals living in a nearby rural village. Ages ranged from 2 to 79 years. All eligible individuals were interviewed. Blood was collected and used to assess hepatitis B virus markers by enzyme-linked immunosorbent assay. Results. Hepatitis B virus infection was found in 232 individuals, or 31% of them; 19 of them (3%) were HBsAg-positive. Of the 754 persons, 149 of them (20%) who reported having been vaccinated against hepatitis B and who presented anti-HBs positivity were classified as vaccine responders. With the multivariate analysis, the variables found to be associated with exposure to hepatitis B virus were having begun sexual relations, having been vaccinated against yellow fever with a needle-free jet injection gun (for the age group < 20 years), and being an immigrant from southern Brazil (> 20 years). Vaccine coverage was low among individuals older than 10 years. The largest share of susceptible individuals (74%) were found in the age group of 11 to 20 years. Conclusions. Our data suggest that hepatitis B virus vaccine coverage in Brazil should be extended to include teenagers in populations that have a low to moderate hepatitis B virus prevalence. It is likely that our results can be extrapolated to other areas of Latin America with a similar epidemiological pattern

Objetivo. Realizar um inquérito soro-epidemiológico sobre infecção pelo vírus da hepatite B em um município do médio-norte do Estado de Mato Grosso, que corresponde à região limítrofe entre o cerrado e a bacia amazônica. Métodos. A amostra incluiu famílias escolhidas aleatoriamente na sede do município, assim como toda a população de uma comunidade rural, totalizando 754 indivíduos. A idade variou de 2 a 79 anos. Os participantes foram entrevistados e tiveram amostras de sangue colhidas para pesquisa de marcadores do vírus da hepatite B por método imunoenzimático. Resultados. A infecção pelo vírus da hepatite B foi constatada em 31% da amostra, sendo 3% positivos para o HBsAg. Os 149 (20%) com história de vacinação e anti-HB positivo isoladamente foram considerados respondedores à vacina. As variáveis associadas à exposição ao vírus da hepatite B por análise multivariada foram: já ter iniciado atividade sexual, ter sido vacinado com pistola pressurizada contra febre amarela (entre aqueles com menos de 20 anos) e ser migrante oriundo do Sul do Brasil (indivíduos com mais de 20 anos). A cobertura vacinal foi baixa entre indivíduos com mais de 10 anos de idade. O maior número de suscetíveis (74%) foi encontrado na faixa dos 11 aos 20 anos. Conclusões. No Brasil, a vacinação contra a hepatite B deve ser estendida quanto antes aos adolescentes nas regiões de baixa a moderada prevalência. É provável que os dados obtidos no presente estudo possam ser extrapolados para outras regiões da América Latina com padrão epidemiológico semelhante

Marcadores sorológicos de hepatite B em indivíduos submetidos a exames de sangue em unidades de saúde / Serological markers of hepatitis B in people submitted to blood testing in health care clinics

Objetivo: Estudar aspectos da epidemiologia da hepatite B em pessoas submetidas à coleta de sangue em unidades de saúde. Métodos: Indivíduos dos quais se coletou sangue em unidades de saúde de Ribeiräo Preto, independentemente do motivo, foram solicitados a fornecer uma quantidade adicional de material, obtida no momento da coleta e submetida à detecçäo de marcadores de hepatite B. Simultaneamente, por meio de questionário padronizado, foram obtidas informaçöes de possíveis fatores de risco para a doença. Os dados foram analisados por meio de um modelo de regressäo logística. Resultados: As prevalências de HBsAg e de anti-HBcAg foram de 0,3 por cento e 13,9 por cento, respectivamente. Os fatores de risco associados à infecçäo foram: idade, residência na cidade há menos de 1 ano, antecedente de hepatite, exposiçäo prévia a casas de correçäo e homo/bissexualismo masculino. Conclusöes: Devido a dificuldades crescentes de obtençäo de sangue de indivíduos sadios, essa pode ser uma alternativa para estudos que objetivem fornecer informaçöes sobre a circulaçäo de agentes infecciosos na populaçäo. Embora näo se possa generalizar os dados obtidos pela metodologia usada, ela traz conhecimento referente à circulaçäo do vírus de hepatite B

Age-specific prevalence of antibodies to hepatitis A in children and adolescents from Rio de Janeiro, Brazil, 1978 and 1995. Relationship of prevalence to environmental factors

The age-specific prevalence of antibodies to hepatitis A virus (anti-HAV) was determined in two different population groups with low socio-economic status from Rio de Janeiro city, Brazil, whose serum were collected 17 years apart (Population 1, 1978; Population 2, 1995). In Population 2, analysis of the anti-HAV prevalence was also carried out with respect to environmental factors. Population 1 was composed of 520 stored sera collected from the umbilical cord of term neonates and children aged 1 month to 6 years. In population 2, 720 serum samples were collected from children and adolescents with ages ranging from 1 to 23 years. The overall prevalence rate of anti-HAV in Population 1 and 2 was 65.6 per cent and 32.1 per cent, respectively. In Population 1, the anti-HAV prevalence reached 88 per cent at the age of 3, while in Population 2, it increased from 4.5 per cent in children under the age of 3 to 66 per cent in the group of adolescents over the age of 14. The low exposure to HAV infection in younger children from Population 2 could be a result of improved environmental hygiene and sanitation, as demonstrated by the presence of piped water, waste and sewage disposal systems in most houses from this population group. These findings indicate a possible change in the prevalence of hepatitis A in Rio de Janeiro.

Influência da migraçäo na prevalência de marcadores sorológicos de hepatite B em comunidade rural. 1 - Análise de prevalência segundo local de nascimento / Influence of migration on prevalence of serological hepatitis B markers in a rural community. 1 - Analysis of prevalence by birthplace

Como parte de uma investigaçäo epidemiológica de campo, sobre hepatite B num município de características rurais do Estado de Säo Paulo, Brasil, foi estudada a distribuiçäo de marcadores sorológicos dessa doença segundo a área de residência e o local de nascimento dos indivíduos. Para o município estudado como um todo, a prevalência encontrada para um ou mais dos marcadores sorológicos de hepatite B foi de 7,7 por cento, com os habitantes rurais apresentando risco mais elevado que os urbanos (9,8 por cento e 4,9 por cento, respectivamente). A análise da positividade, de acordo com o local de nascimento, mostrou valores mais altos entre os migrantes provenientes de outros Estados do país (15,8 por cento), seguidos dos oriundos de outros municípios de Säo Paulo (9,2 por cento): entre os nascidos no município estudado e, particularmente em Ribeiräo Preto, centro urbano de localizaçäo próxima ao mesmo, observaram-se as menores prevalências (5,2 por cento e 2,5 por cento, respectivamente). Discute-se a importância de se analisar em estudos epidemiológicos, a procedência dos indivíduos, variável capaz de influir na história natural da hepatite B numa comunidade, e, eventualmente, explicar diferenças nas distribuiçöes de marcadores dessa infecçäo em populaçöes aparentemente semelhantes.

Influência da migraçäo na prevalência de marcadores sorológicos de hepatite B em comunidade rural. 2 - Análise comparativa de algumas características das populaçöes estudadas / Influence of migration on prevalence of serological hepatitis B markers in a rural community. 2 - Comparative analysis of some characteristics of the population studied

A associaçäo entre prevalência de marcadores sorológicos de hepatite B e local de nascimento, verificado em estudo realizado num município de características rurais do Estado de Säo Paulo, Cássia dos Coqueiros, sugere existirem diferenças entre migrantes e näo-migrantes no que diz respeito a fatores de risco para hepatite B. Esses dois grupos foram analisados segundo as variáveis escolaridade, ocupaçäo profissional, número de hospitalizaçöes, antecedente de transfusöes sangüíneas e tipo de tratamento dentário prévio. A comparaçäo entre os grupos mostra que migrantes, particularmente de outros Estados do país, apresentam baixos níveis de escolaridade, elevadas proporçöes de lavradores empregados, maior número de internaçöes prévias e maiores exposiçöes a transfusöes sangüíneas e a procedimentos odontológicos mais agressivos. Observaram-se ainda associaçöes entre a prevalência de marcadores de hepatite B e as variáveis escolaridade, ocupaçäo profissional, número de hospitalizaçöes e tipo de tratamento odontológico, muito embora as duas últimas näo justifiquem as maiores prevalências entre os migrantes. A distribuiçäo de marcadores de hepatite B parece ser resultado da pior condiçäo socioeconômica dos migrantes, refletida pelo seu nível inferior de escolaridade e pela predominância de ocupaçöes secundárias

Prevalência de marcadores sorológicos de hepatite B numa pequena comunidade rural do Estado de Säo Paulo, Brasil / Prevalence of serological markers of hepatitits B in a small rural community of S. Paulo State, Brasil

Foi realizado estudo epidemiológico com vistas a determinar a prevalência de marcadores sorológicos de hepatite B na populaçäo de um pequeno município, de características rurais, do Estado de Säo Paulo. Observou-se prevalência total de marcadores igual a 7,74 por cento, com valores de HBsAg, anti-HBs e anti-HBc, respectivamente iguais a 0,10 por cento, 1,69 por cento e 7,64 por cento. Ressalta-se a importância da determinaçäo do anti-HBc em estudos epidemiológicos, bem como discute-se a relevância de se comparar a reduzida circulaçäo viral, observada na área, com as elevadas prevalências verificadas em outras regiöes, buscando assim levantar hipóteses acerca de mecanismos alternativos de transmissäo