RESUMO
To investigate the accuracy of the polymerase chain reaction (PCR) method for the detection of Toxoplasma gondii in clinical specimens, aliquots of amniotic fluid to which known amounts of Toxoplasma gondii DNA had been added were tested by five European Centres. Four laboratories were able to detect DNA at levels equivalent to ten tachyzoites or less, including two that detected DNA equivalent to a single parasite. Two laboratories erroneously found one of eight negative control samples to be positive. These findings confirm that the high level of sensitivity associated with the PCR method can be readily achieved under routine laboratory conditions, but they also underscore the potential for both false-positive and false-negative findings to occur. Furthermore, the results confirm the urgent need for an external quality assurance scheme to support laboratories employing PCR in a clinical context for the detection of Toxoplasma gondii.
Assuntos
Líquido Amniótico/parasitologia , Técnicas de Laboratório Clínico/normas , DNA/isolamento & purificação , Reação em Cadeia da Polimerase/métodos , Toxoplasma/isolamento & purificação , Toxoplasmose Congênita/diagnóstico , Animais , Europa (Continente) , Reações Falso-Negativas , Reações Falso-Positivas , Feminino , Humanos , Gravidez , Sensibilidade e EspecificidadeRESUMO
The influence of a homologous gamma interferon preparation (MuIFN-gamma) on in vitro spreading of freshly-seeded unelicited mouse peritoneal macrophages (MPM) was tested. Light microscopy and scanning electron microscopy observations gave comparable results. Addition of MuIFN-gamma enhanced the spreading on solid surfaces, especially 3-5 hours after seeding. Maximal effect was achieved with 10 units of IFN. Addition of specific anti-MuIFN-gamma or treatment of the preparation at pH 2 eliminated both antiviral activity and effect on spreading of MPM.
