Dichlorodiphenyldichloroethylene exposure during the first trimester of pregnancy alters the anal position in male infants.

Anogenital distance (AGD) at birth is regarded as a useful measurement that reflects the prenatal androgenic status in rodents. However, the impact of xenoantiandrogens on human development is largely unknown. The aim of this study was to evaluate the potential antiandrogenic impact of prenatal DDT metabolites (p,p'-DDE and p,p'-DDT) exposure on infant AGD, using a non-age-dependent anal position index (API). As part of an ongoing perinatal cohort study on the effects of organochlorine pesticides in children's neurodevelopment, we conducted a cross-sectional study in 71 infants (37 males and 34 females). Maternal serum levels of DDT metabolites (p,p'-DDE and p,p'-DDT) before and during each trimester of pregnancy were determined by electron capture gas-liquid chromatography. During postnatal home visits at 3, 6, and 12 or 18 months of age, the children's weight and API were evaluated. Multiple lineal regression models were used to estimate the potential endocrine disruptor activity of prenatal p,p'-DDE exposure. Boys had significantly higher API values than girls (0.6 versus 0.5; P < 0.001). Only among boys, a doubling increase of maternal p,p'-DDE serum levels during the first trimester of pregnancy, were associated with a significant reduction of API (beta=-0.02; P= 0.02). No effect of p,p'-DDT on AGD was observed. Evidence of the effect of prenatal p,p'-DDE on external genital differentiation is scarce and not consistent in the literature. Further studies are needed to confirm a hormonal disruptive effect on the development of external genitalia, due not only to p,p'-DDE but also due to other antiandrogenic persistent compounds.

[Nitazoxanide vs albendazole against intestinal parasites in a single dose and for three days]. / Evaluación de la nitazoxanida en dosis única y por tres días en parasitosis intestinal.

OBJECTIVE: To assess the effectiveness of the usual dose of nitazoxanide administered for three days and as a single dose for massive eradication of intestinal parasites in the pediatric population, compared with single-dose albendazole. MATERIAL AND METHODS: A randomized clinical trial was conducted in three rural communities in central Mexico City between 2001 and 2003 to assess three possible therapy regimes in a study population of 786 children 5 to 11 years of age, 92 of whom had a positive parasitology test result (15.1%). Group 1 included 27 patients treated with 400 mg given as a single dose of albendazole; group 2 included 34 patients whose therapy consisted of a 15 mg/kg/day dose for three consecutive days; patients in group 3 (n=31) were administered a single 1.2 g dose of nitazoxanide. Differences in proportions were assessed using Fisher's exact test. RESULTS: No statistically significant differences were found in the effectiveness of the three treatment regimes: 80.5% with albendazole, compared with the two nitazoxanide alternatives (67.6% and 71%, respectively.A higher prevalence of side effects was observed with nitazoxanide in the three-day regimen (26.5%) and as a single dose (32.2%), compared with a single dose of albendazole (7.4%). CONCLUSIONS: According to the evidence on effectiveness and side effects, the use of nitazoxanide is not justified as a massive prophylactic medication for intestinal parasitosis control alternative in endemic areas. In countries with a high prevalence of intestinal parasitosis primary prevention measures should be the most important strategy, together with public sanitation, drinking water and sewage system availability, water chlorination, and appropriate animal fecal waste disposal, as well as health education.

Evaluación de la nitazoxanida en dosis única y por tres días en parasitosis intestinal / Nitazoxanide vs albendazole against intestinal parasites in a single dose and for three days

OBJETIVO: Evaluar la utilidad de nitazoxanida en dosis habitual con esquema de tres días y en dosis única, para la erradicación masiva de parásitos intestinales en la población pediátrica, comparando su efecto con el del albendazol en dosis única. MATERIAL Y MÉTODOS: Se realizó un ensayo clínico aleatorizado, en tres comunidades rurales de la región central de México, durante el periodo 2001-2003, para incluir tres posibles alternativas de tratamiento en 786 sujetos de entre 5 y 11 años de edad, de los cuales 92 tuvieron un examen parasitológico positivo (15.1 por ciento). El grupo 1 incluyó 27 pacientes que recibieron 400 mg de albendazol en dosis única; el grupo 2 incluyó 34 pacientes a quienes se administró nitazoxanida en dosis de 15 mg/kg/día durante tres días consecutivos; y el grupo 3 incluyó 31 pacientes que recibieron 1.2 g de nitazoxanida en dosis única. Se evaluó diferencia de proporciones mediante prueba exacta de Fisher. RESULTADOS: No existieron diferencias estadísticamente significativas en la efectividad de los tres esquemas de tratamiento: (80.5 por ciento) con albendazol, comparado con las dos alternativas adicionales de nitazoxanida (67.6 por ciento y 71 por ciento, respectivamente). Se observó una mayor prevalencia de efectos secundarios con nitazoxanida por kg /día (26.5 por ciento) y en dosis única (32.2 por ciento), en comparación con la dosis única de albendazol (7.4 por ciento). CONCLUSIONES: Las evidencias en cuanto a la efectividad y elevada prevalencia de efectos secundarios de la nitazoxanida no justifican aún su utilización como quimiopreventivo masivo para el control de parasitosis intestinal en áreas endémicas. En países con elevada prevalencia de parasitosis intestinal las medidas de prevención primaria que continúan vigentes, y que deben priorizarse, están relacionadas con sanidad pública, introducción de agua potable y drenaje, cloración de agua y manejo adecuado de excretas de animales domésticos, así como educación para la salud.