Tinea capitis. Emergencia de Microsporum audouinii y Trichophyton tonsurans en la República Dominicana / Emergence of Microsporum audouinii and Trichophyton tonsurans as Causative Organisms of Tinea Capitis in the Dominican Republic

Antecedentes: Las tiñas de la cabeza predominan en los niños, con una frecuencia y etiología variables en diferentes partes del mundo. Objetivos: Comunicar los datos epidemiológicos y micológicos de tiña del cuero cabelludo observados en la zona urbana y rural de la República Dominicana. Metodología: Se estudiaron 118 muestras de pacientes con diagnóstico de tiña de la cabeza en la República Dominicana, 63 de dos escuelas urbanas en la capital Santo Domingo (53%) y 55 de escuelas rurales en la frontera dominico-haitiana (47%). Resultados: Se estudiaron 84 varones (71,18%) y 34 mujeres (28,81%). En la zona urbana predominó en los varones (84,12%). La edad con mayores porcentajes fue entre 6 y 8años (47,45%), de 3 y 5 años (24,59%) y 9 y 11 años (16,94%). En la zona urbana se aislaron M. audouinii (39,68%), T. tonsurans (23,80%), M. canis (19,04%) y T. violaceum (1,58%) y en la zona rural T. tonsurans (87%) y T. mentagrophytes (2%) y globalmente T. tonsurans (61,16%), M. audouinii (24,27%) y M. canis (11,65%) y rara vez T. violaceum y T. mentagrophytes. Conclusiones: En la República Dominicana, en la zona urbana, la tiña de la cabeza predomina en los varones y en la zona rural tiene una frecuencia similar en ambos sexos. Se detectó una emergencia por M. audouinii, un incremento de Trichophyton tonsurans, y una estabilidad con frecuencia más baja de M. canis. En la zona rural y la frontera con Haití hay un predominio significativo de T. tonsurans (AU)

Background: Tinea capitis affects mainly children. The frequency and causative organism vary from region to region. Objectives: To provide epidemiological and mycological data on tinea capitis collected in urban and rural areas of the Dominican Republic. Methods: Samples were obtained from 118 patients with tinea capitis. Sixty-three of these were from 2 schools in urban areas of the Dominican capital Santo Domingo (53%) and 55 were from rural schools on the border with Haiti (47%). Results: The study included 84 boys (71.18%) and 34 girls (28.81%). The urban sample comprised mainly boys (84.12%). The most represented age ranges were 6 to 8 years (47.45%), 3 to 5 years (24.59%), and 9 to 11 years (16.94%). Microsporum audouinii (39.68%), Trichophyton tonsurans (23.80%), Microsporum canis (19.04%), and Trichophyton violaceum (1.58%) were isolated from children in urban areas, whereas T. tonsurans (87%) and Trichophyton mentagrophytes (2%) were isolated from those in rural areas. Overall, T. tonsurans (61.16%), M. audouinii (24.27%), and M canis (11.65%) were the most frequently isolated causative organisms, whereas T. violaceum and T. mentagrophytes were rarely reported. Conclusions: In urban areas of the Dominican Republic, tinea capitis was found mainly in boys, but in rural areas it was evenly distributed among boys and girls. The emergence of M. audouinii and an increase in T. tonsurans were found while M. canis continued to be present at lower frequencies. On the rural border with Haiti, there was a significant predominance of T. tonsurans (AU)

Differential efficacy of lipophilic and cytosolic antioxidants on generation of reactive oxygen species by amyloid-beta.

Exposure of neurons to amyloid-beta (Abeta) is accompanied by a cascade of oxidative damage that initiates with lipid peroxidation followed by subsequent generation of cytosolic free radicals and reactive oxygen species (ROS). The antioxidant vitamin E has been utilized to counteract Abeta-induced oxidative stress. We considered herein whether or not the lipid-solubility of vitamin E limits its neuroprotection to membrane-related oxidative damage, and renders it relatively ineffective where prior lipid peroxidation has already generated cytosolic free radicals and ROS. To test this possibility, we treated differentiated SH-SY-5Y human neuroblastoma with vitamin E or a cell-permeant antioxidant, N-acetyl cysteine (NAC), simultaneously with or 15 min after the application of Abeta. Both vitamin E and NAC prevented Abeta-induced ROS generation when applied simultaneously with Abeta, but only NAC prevented Abeta-induced ROS generation when added to cultures that had previously been exposed to Abeta. These results support the hypothesis that vitamin E can quench Abeta-induced lipid peroxidation, but cannot effectively quench ROS generated by prior lipid peroxidation. These findings in cell culture may provide limited insight into why vitamin E is not fully effective against neurodegeneration in AD in clinical settings, since some neuronal populations are likely to already have been compromised by prior Abeta exposure before vitamin E treatment was initiated.