Distribución de los subtipos del VIH-1 en nueve países de América del Sur, 1995-2002 / Distribution on HIV-1 subtypes in nine countries of South America, 1995-2002

Objetivo: Determinar la distribución de los subtipos del virus de la inmunodeficiencia humana (VIH-1) y la presencia de cepas recombinantes en Argentina, Bolivia, Colombia, Chile, Ecuador, Paraguay, Perú, Uruguay y Venezuela a través de estudios epidemiológicos y de genotipificación. Materiales y Métodos: Se incluyeron a los participantes de los protocolos realizados en los nueve paises, incluyendo poblaciones de trabajadoras sexuales (TS), hombres que tienen sexo con hombres (HSH), individuos VIH positivos, gestantes y pacientes con tuberculosis (TB). Se utilizó la prueba de movilidad heteroduplex de envoltura (env HMA), ProRT, secuenciamiento completo o ambas para determinar los subtipos de VIH 1. Resultados: Se identificaron 3081 individuos positivos al VIH (de un total de 42 290voluntarios), las prevalencias oscilaban entre menos de 1 por ciento a 29 por ciento según población estudiada, siendo mayor en los HSH. Un total de 1654 muestras (54 por ciento) fueron genotipificadas. Se encontró el subtipo B en 1380 (83 por ciento) muestras, el subtipo F en 218 (13 por ciento), así como los subtipos A y C en 0,1 por ciento y 0,4 por ciento respectivamente. Se hallaron subtipos recombinantes BF en 39 muestras (2 por ciento) y formas recombinantes CRF01_AE(0,1 por ciento), CRF17_BF(0,4 por ciento) y CRF02_AG(0,1 por ciento). En Venezuela, Colombia, Ecuador, Perú, Bolivia y Chile (paises andinos) predominó el subtipo B, mientras en Argentina, Uruguay y Paraguay hubo un alto porcentaje del subtipo F. Conclusiones: En la mayoría de países andinos la epidemia de VIH-1 se concentró en los HSH con un predominio del subtipo B. El subtipo F es másfrecuente en las TS en Argentina y Uruguay. Esta información es útil para implementar planes de prevención y futuros ensayos de vacunas en esta región.

Objectives: To determine human immunodeficiency virus type 1 (HIV-1) subtype distribution, and the presence of recombinant strains in Argentina, Bolivia, Colombia, Chile, Ecuador, Paraguay, Peru, Uruguay, and Venezuela using epidemiological and genotyping studies. Materials and Methods: Participants in the studies performed in nine countries were included, amongst them female sex workers, men who have sex with men (MSM), HIV-positive individuals, pregnant women, and patients with tuberculosis (TB) were included. Envelope-base heteroduplex mobility assay (env HMA) testing was used, as well as ProRT, complete sequencing, or both for determining HIV-1 subtypes. Results: 3081 HIV positive individuals were identified (out of 42 290 volunteers), prevalences from less than 1% to 29% in the different populations studied, and it was higher among MSM. 1654 samples (54%) underwent genotyping. B subtype was found in 1380 (83%) samples, F subtype was found in 218 (13%) samples, and A and C subtypes were found in 0,1% and 0,4%, respectively. BF recombinant serotypes were found in 39 samples (2%), and CRF01_AE (0,1%), CRF17_BF (0,4%), and CRF02_AG (0,1%) were also found. In Venezuela, Colombia, Ecuador, Peru, Bolivia, and Chile (Andean countries) subtype B predominated, while in Argentina, Uruguay, and Paraguay there was a high frequency of F subtype. Conclusions: In most Andean countries, HIV-1 epidemic concentrated among MSM, who are predominantly infected with B subtype. F subtype is more frequent among female sex workers in Argentina and Uruguay. This is useful information in order to implement prevention plans and future vaccine tests in this region.

Carotenoids and human health

After the discovery of vitamin A in 1913, the yellow pigments of fruits and vegetables were soon implicated as compounds with similar nutritional affects B-carotene was shown to be converted intro vitamin A by moore in 1929, and chemical structures of both vitamin A and ß-carotone were determined two years later. Thus, the sole function of ß-carotene in human health was considered to be its conversion into vitamin A. On the basis of observational epidemiologic studies, conducted in the mid-1970s, however, carotenoids were implicated as protective agents, firts against lung cancer and then against a variety of other chronic diseases. Intervention trials employing ß-carotene, however, either have shown no preventive effect or indeed, in two cases, have echanced the incidence of lung cancer in middle-aged male smokers and asbestos workers. The possible protective action of carotenoids can be attributed to their properties as singlet oxygen quenchers and antioxidants, whereas their cancer-enchancing actions in lung can be ascribed to the prooxidant action of carotenoid free radicals in damaged cells. Apart from chronic disease, ß-carotene has shown significant therapeutic value in individuals suffering from photosensitivity disorders and provides temporary relief to persons afflicted with leukoplakia. Apart from a medical contex, the colored carotenoids found in many living organisms and in many foods delight both the eye and the palate. Thus, human health and the enjoyment of life are greatly benefited by the presence of these interesing pigments in nature, whether or not they ultimately prove to have more specific protective affects againts chronic diseases

Bioavailability of carotenoids

Nuestros conocimientos actuales sobre la biodisponibilidad de los carotenoides en alimentos son insuficientes, fragmentados y difíles de interpretar. Métodos pasados para calcular el valor de vitamina A de los carotenoides alimenticios padece tanto de la incertidumbre sobre el significado del término biodisponibilidad como de la inadecuacidad de los indicadores usados en su determinación. Las razones reportadas para la conversión del ß-caroteno en vitamina A en humanos in vivo, dependiendo de las condiciones, varían de 2:1 a 26:1 (µg/µg). Así, la razón de 6:1, establecida por la Organización Mundial de la Salud, debe ser considerada como un estimativo promedio aproximado que no se aplica para todas las dietas. Las estrategias para aumentar el consumo de los alimentos que contienen carotenoides deben incluir medidas para realizar la biodisponibilidad de los carotenoides