RESUMO
A stochastic model for the in vivo micronucleus assay is presented. This model describes the kinetic of the rate of micronucleated polychromatic erythrocytes induced by the administration of a mutagenic compound. For this, biological assumptions are made both on the erythropoietic system and on the mechanisms of action of the compound. Its pharmacokinetic profile is also taken into account and it is linked to the induced toxicological effect. This model has been evaluated by analyzing the induction of micronuclei is mice bone marrow by a mutagenic compound, 6-mercaptopurine (6-mp). This analysis enabled to make interesting remarks about the induction of micronuclei by 6-mp and to put to light an unsuspected wavy kinetic by optimizing the experimental design of the in vivo micronucleus assay.
Assuntos
Testes para Micronúcleos , Modelos Biológicos , Mutagênicos/farmacocinética , Mutagênicos/toxicidade , Animais , Eritropoese/efeitos dos fármacos , Cinética , Cadeias de Markov , Mercaptopurina/farmacocinética , Mercaptopurina/toxicidade , Camundongos , Análise Numérica Assistida por Computador , Processos EstocásticosRESUMO
Serological prevalence of Flaviviridae was studied on Reunion Island by testing 2,507 human sera from a randomised sample. Each serum was tested against 5 viruses (yellow fever, dengue type 1 and 2, West Nile and Wesselsbron) using haemagglutination inhibition test: 42.68% of human sera were found positive. The multivalent reactions represent practically three fourths of the positive ones. A severe dengue type 2 outbreak on the island in 1977-1978 and the possible circulation of a Flavivirus may explain these data. Among the tested subjects, positivity frequencies vary according to their age and their living surrounding. These results were compared with those of a previous serosurvey performed in 1971 and showed an important increase in the serological prevalence largely explainable by the 1977-1978 epidemic.
Assuntos
Infecções por Flaviviridae/epidemiologia , Adolescente , Adulto , Fatores Etários , Animais , Animais Domésticos , Antígenos Virais/sangue , Vírus da Dengue/imunologia , Feminino , Infecções por Flaviviridae/imunologia , Hemaglutinação por Vírus , Humanos , Masculino , Pessoa de Meia-Idade , Prevalência , Reunião/epidemiologia , Saúde da População Rural , Estudos Soroepidemiológicos , Fatores Sexuais , Vírus do Nilo Ocidental/imunologia , Vírus da Febre Amarela/imunologiaRESUMO
A serological ELISA test for diagnosis of avian salmonellosis infections with Salmonella typhimurium or enteritidis has been established. Plates were coated half with a negative antigen and half with a positive antigen. Both negative and positive antigens were adsorbed with a monovalent agglutinant anti Escherichia coli serum prior to being distributed into wells of the plates. Sera from SPF birds and from SPF birds vaccinated and/or inoculated with numerous viruses or bacteria, or sera from conventional birds bacteriologically free of any salmonellosis were tested and the percentage of false positive reactions was inferior than 1%. In groups of birds naturally infected or experimentally inoculated with Salmonella enteritidis or typhimurium the percentages of positive individuals were ranged from 15 to more than 90% according to the doses and routes of inoculation and the delay between contamination and sampling.
Assuntos
Galinhas , Patos , Doenças das Aves Domésticas/diagnóstico , Salmonelose Animal/diagnóstico , Animais , Ensaio de Imunoadsorção Enzimática , Salmonella enteritidis/imunologia , Salmonella typhimurium/imunologia , Organismos Livres de Patógenos EspecíficosRESUMO
Necrotizing pancreatitis is observed in 2 to 4 week-old guinea poult. Virus isolation was attempted from the pancreata of naturally affected birds. The isolate was identified as a type 1 adenovirus, and it reproduced the disease when inoculated to sensible guinea fowl.
Assuntos
Infecções por Adenoviridae/veterinária , Aviadenovirus/isolamento & purificação , Pâncreas/microbiologia , Pancreatite/veterinária , Doenças das Aves Domésticas/microbiologia , Doença Aguda , Infecções por Adenoviridae/microbiologia , Animais , Microscopia Eletrônica , Pancreatite/microbiologia , Aves DomésticasRESUMO
Published data have suggested a possible link between the tumor promoting activity and the aneugenic properties of griseofulvin. The present study was conducted to explore this relationship. Griseofulvin was evaluated both for its potential promoting activity in liver carcinogenesis in partially hepatectomized F344 male rats initiated by diethylnitrosamine and for its genotoxic potential in the peripheral blood micronucleus assay. Rats were treated daily with 2,000 mg/kg body weight by oral gavage for 12 weeks in the medium-term carcinogenesis bioassay. GST-P-positive foci (mean number and surface area) and altered cell foci were compared in the liver of rats treated with griseofulvin alone, diethylnitrosamine alone,and griseofulvin in addition to diethylnitrosamine by using immunohistochemical and histopathological evaluation, respectively. This evaluation allowed the conclusion that griseofulvin did not initiate the carcinogenic process but rather had a potential in the liver for tumor promoting activity. Griseofulvin was found to be negative in the rat peripheral blood micronucleus test when given at a daily oral dose of 2,000 mg/kg body weight for at least 3 weeks.