RESUMO
The role of Helicobacter pylori infection in gastric cancer was evaluated in a high-risk population in Venezuela using serological assays in a study of 302 cases and 483 neighborhood controls. To investigate the claim that assays for H. pylori should use antigens derived from local strains, four different assays derived from Venezuelan and European strains were used. Prevalence of IgG H. pylori antibodies in controls was very high, with estimates between 72 and 92%. Prevalence was similar in cases and controls. However, cases had lower antibody titers. This effect was observed only in subjects with low pepsinogen (PG) levels PGI/PGII <3.0), which suggested that extensive atrophy in cases causes a loss of H. pylori infection, with a consequent reduction in antibody titer. In addition, advanced cases (stage II or higher) had lower antibody titers than less advanced cases, which indicated that the lower antibody titers in cases may be attributable partially to a diminished immune response. All of the four assays for anti-H. pylori antibodies gave similar results. No evidence was found for the superiority of the assay based on Venezuelan strains. These results are consistent with other case-control studies in high-risk populations and highlight the difficulties of investigating H. pylori infection in retrospective studies.
Assuntos
Antígenos de Bactérias , Infecções por Helicobacter/epidemiologia , Helicobacter pylori/patogenicidade , Neoplasias Gástricas/microbiologia , Adulto , Idoso , Idoso de 80 Anos ou mais , Anticorpos Antibacterianos , Proteínas de Bactérias/sangue , Estudos de Casos e Controles , Ensaio de Imunoadsorção Enzimática , Feminino , Infecções por Helicobacter/sangue , Infecções por Helicobacter/complicações , Helicobacter pylori/imunologia , Humanos , Masculino , Pessoa de Meia-Idade , Pepsinogênio A/análise , Prevalência , Especificidade da Espécie , Neoplasias Gástricas/complicações , Neoplasias Gástricas/epidemiologia , Neoplasias Gástricas/imunologia , Neoplasias Gástricas/patologia , Venezuela/epidemiologiaRESUMO
Markers of hepatitis delta virus (HDV) infection have been detected all over the five continents. Geographical prevalence varied heavily: HDV infection is very rare in Far East Asia, but extremely frequent in Arabian countries, in Romania and in certain Indian populations of South America. In Europe and in the USA the infection is widely spread among high risk groups such as intravenous drug abusers and haemophiliacs.
Assuntos
Hepatite D/epidemiologia , África , Austrália , Estudos Transversais , Europa (Continente) , Ásia Oriental , Hepatite D/transmissão , Humanos , Oriente Médio , América do Sul , Estados UnidosAssuntos
Antígenos de Superfície da Hepatite B/análise , Vírus Delta da Hepatite , Hepatite/imunologia , Adulto , Portador Sadio/imunologia , Chile , Feminino , Hepatite/epidemiologia , Anticorpos Anti-Hepatite B/análise , Hepatite D/epidemiologia , Humanos , Cirrose Hepática/imunologia , Neoplasias Hepáticas/imunologia , MasculinoRESUMO
Over a 3-year period, 149 Yucpa Indians in Venezuela developed hepatitis; 34 persons died and at least 22 developed chronic hepatitis. Children and young adults were primarily affected, especially males. Serologic testing showed that hepatitis B virus infection was highly endemic in this population, but also that 65% of patients had hepatitis B virus surface antigen (HBsAg) during or after illness. Most patients had evidence of delta-agent superinfection; 86% of HBsAg-positive patients had delta antibody, and delta antigen was found in specimens taken during autopsies on 7 of 9 patients. Serologic data suggested that most infections were due to delta superinfection of hepatitis B carriers, and that more than 60% of these infections progressed to chronic disease. Delta agent infection, and particularly delta superinfection of hepatitis B carriers, appears to be an ominous occurrence that may develop in populations among whom hepatitis B virus infection is endemic, and who have no other risk factor for delta infection.
Assuntos
Surtos de Doenças/epidemiologia , Hepatite Viral Humana/microbiologia , Adolescente , Adulto , Portador Sadio , Criança , Pré-Escolar , Feminino , Hepatite B/complicações , Antígenos de Superfície da Hepatite B/análise , Hepatite Crônica/etiologia , Hepatite Viral Humana/epidemiologia , Hepatite Viral Humana/patologia , Humanos , Indígenas Sul-Americanos , Lactente , Masculino , VenezuelaRESUMO
To supplement a detailed epidemiologic study of an outbreak of viral hepatitis in Venezuelan Indians in isolated valleys, apparently resulting from delta agent infection, 10 autopsy specimens were studied histologically and immunocytochemically, and five biopsy specimens were examined. The patients were children and young adults and predominantly males. A sequence of hepatitis from focal necrosis with conspicuous small-droplet steatosis, through massive necrosis, prolonged postnecrotic collapse to early cirrhosis with massive collapse was postulated. The histologic changes tentatively suggest a cytopathic effect of the delta agent without significant indication of lymphocytotoxicity, at least in the parenchyma. Delta agent was demonstrated in hepatocyte nuclei in moderate amounts in the focal-necrotic stage and in isolated cells in the massive-necrotic stage, but in large amounts during the transition to cirrhosis. Whether these patients, in whom neither HBcAg nor HBsAg were demonstrable in the liver, suffered exclusively from superinfection of hepatitis B virus carriers and/or coinfection of hepatitis B virus with the delta agent remains to be resolved. Delta infection may occur in isolated settings with no relation to Italian origin, drug addiction, or polytransfusion. The infection is far more widely spread than previously assumed.