Reacción en cadena de la polimerasa "on-stage" y "nested": comparación de dos métodos para detectar el ARN del virus C en pacientes con hepatitis crónica C tratados con alfa interferón / One-stage and nested polymerase chain reaction: comparison of two methods to detect virus C RNA in patients with chronic hepatitis C treated with alfa interferon

El ARN del virus (HCV RNA) se detecta con la técnica de la reacción en cadena de la polimerasa (PCR), utilizándose dos variantes: la PCR "one-stage" y la PCR "nested". Comparamos ambas variantes en 40 muestras de suero de pacientes con hepatitis crónica C, 20 obtenidas antes del tratamiento con interferón alfa recombinante y 20 al concluir el mismo. El HCV RNA se detectó en 16 (80 ciento por ciento) de las muestras post-tratamiento, con iguales resultados positivos y negativos en ambas variantes. En 7 casos estudiamos las muestras pre y post-tratamiento de los mismos pacientes. Las muestras de los 7 pacientes fueron positivas por PCR "one-stage" y PCR "nested" al comenzar el tratamiento y de sólo 4 al concluirlo (1 con respuesta completa inmediata y 3 no respondedores). Tres pacientes se negativizaron con respuesta completa inmediata. Nuestro estudio muestra una correlación absoluta entre la PCR "one-stage" y la PCR "nested", sin que ésta se modifique por las posibles variaciones de la viremia provocadas por el interferón

Identificación de DNA de papilomavirus humano en condilomas anogenitales de una población masculina / DNA identification of human papillomavirus in anogenital condyloma of a male population

Human Papillomaviruses (HPV) are the cause of benign human anogenital lesions where HPV 6 and HPV 11 are most commonly found. Conversely, HPV 16, 18, 31 and 33 are frequently detected in genital carcinomas and are thus considered as oncogenic types. In order to analyze the prevalence of specific HPV types in an Argentine male population, 43 anogenital lesions from different patients with diagnosis of condyloma acuminata were analyzed. These lesions were localized in different regions of the male genitalia comprising the corona glandis, urethral meatus, skin of the penis, scrotum and anus. The biopsies were screened for the presence of HPV 6, 11, 16, 18, 30, 31 and 33 by Southern blot at different stringent conditions of hybridization (Tm -48 degrees C and Tm -20 degrees C). HPV DNA was found in 41 examined cases (95.3) with a clear prevalence of HPV 6 and HPV 11 types (51.2 and 23.3 respectively). Six samples (14.0) were positive only under nonstringent conditions of hybridization. Mixed infections between HPV 16, 18, 30, 31, 33 or a HPV 30 related type with HPV 6 or HPV 11 were detected in 8 specimens (18.6). Only one case was between HPV 16 and HPV 30. Two additional samples were only positive for HPV 30. Experiments in progress about the prevalence of HPV types in female lesions as well as in normal subjects will contribute to complete the description of the epidemiology of these infections in Argentina.