Age-Related Changes in Ang II Receptor Localization and Expression in the Developing Auditory Pathway.

We studied Ang II receptor localization in different nuclei of the auditory system, by means of binding autoradiography, during brain development. The inferior colliculus (IC), a large midbrain structure which serves as an obligatory synaptic station in both the ascending and descending auditory pathways, exhibited high Ang II AT2 binding at all ages (P0, P8, P15, P30), being maximal at P15. These observations were confirmed by in situ hybridization and immunofluorescence at P15, demonstrating that AT2 receptor mRNA localized at the same area recognized by AT2 antibodies and anti ß III-tubulin suggesting the neuronal nature of the reactive cells. Ang II AT1 receptors were absent at early developmental ages (P0) in all nuclei of the auditory system and a low level was observed in the IC at the age P8. AT2 receptors were present at ventral cochlear nucleus and superior olivary complex, being higher at P15 and P8, respectively. We also explored the effect of prenatal administration of Ang II or PD123319 (AT2 antagonist) on binding of Ang II receptors at P0, P8, P15. Both treatments increased significantly the level of AT2 receptors at P0 and P8 in the IC. Although total binding in the whole IC from P15 animals showed no difference between treatments, the central nucleus of the IC exhibited higher binding. Our results supports a correlation between the timing of the higher expression of Ang II AT2 receptors in different nuclei, the onset of audition and the establishment of neuronal circuits of the auditory pathway.

Riesgo de adquirir ITS/SIDA en niños de barrios marginales de Asunción, Paraguay / Risk of acquiring STD/AIDS in children of slums of Asunción, Paraguay

La diseminación de las infecciones de transmisión sexual/síndrome de inmunodeficiencia adquirida(ITS/SIDA) se presenta principalmente en jóvenes, con una tendencia creciente a la asociación conpobreza y falta de acceso a educación y salud pública. El objetivo del estudio fue explorar lasituación de riesgo y el conocimiento sobre el VIH/SIDA en niños de 9-15 años que asistían a loscolegios del Barrio Santa Ana y Ricardo Brugada. El consentimiento para el estudio fue solicitado alas autoridades del colegio y a los padres. Se les aplicó un cuestionario administrado por unaencuestadora, que incluía el nivel de conocimientos sobre los factores de riesgo, sobre las formasde prevención para la infección por VIH. Un total de 297 niños participaron en el estudio, 173(58%) de sexo femenino, la mayoría (86%) vivían en condiciones de hacinamiento. Del 28 % quetrabajaban, 66% de los varones eran vendedores ambulantes y el 49 % de las niñas eranempleadas domésticas. El 80 % no conocía las formas de transmisión del ITS/SIDA, ni que elpreservativo puede prevenir la transmisión. El 9% (11/24) de los varones y el 2% (3/173) de lasniñas tuvieron relaciones sexuales. El 10% refieren abusos sexuales. El 25% ingieren bebidasalcohólicas, el 2% consume drogas inhalantes. En conclusión, este estudio muestra un importantedesconocimiento sobre las ITS/SIDA, formas de prevenirlas, la falta de percepción de riesgo concondiciones ambientales y socioeconómicas que la favorecen. Estos resultados plantean la urgentenecesidad de iniciar campañas de prevención en este grupo

Angiotensin II type 1 receptor A1166C gene polymorphism and essential hypertension in San Luis

Essential hypertension is considered a multifactorial trait resulting from a combination of environmental and genetic factors. The angiotensin II type 1 receptor mediates the vasoconstrictor and growth-promoting effects of Ang II. The A1166C polymorphism of the AT1 receptor gene may be associated with cardiovascular phenotypes, such as high arterial blood pressure, aortic stiffness, and increased cardiovascular risk. We investigated the association between this A1166C polymorphism and hypertension in hypertense and normotense subjects from San Luis (Argentina) by mismatch PCR-RFLP analysis. Hypertense patients exhibited significant increases in lipid related values and body mass index. The frequency of occurrence of the C1166 allele was higher among patients with hypertension (0.19) than in the control group (0.06). No significant association was found between this polymorphism and essential hypertension in the study population, although the AC genotype prevalence was higher in patients with hypertension and positive family history of hypertension (32%) than in control subjects (12%). Patients with the A1166C polymorphism exhibited higher levels of serum total cholesterol, LDL-cholesterol and BMI than in control subjects. Taken together the genotype and biochemical parameters and considering the restrictive selection criteria used, the present results suggest a correlation between AT1 A1166C gene polymorphism and risk of cardiovascular disease.

Angiotensin II type 1 receptor A1166C gene polymorphism and essential hypertension in San Luis

Essential hypertension is considered a multifactorial trait resulting from a combination of environmental and genetic factors. The angiotensin II type 1 receptor mediates the vasoconstrictor and growth-promoting effects of Ang II. The A1166C polymorphism of the AT1 receptor gene may be associated with cardiovascular phenotypes, such as high arterial blood pressure, aortic stiffness, and increased cardiovascular risk. We investigated the association between this A1166C polymorphism and hypertension in hypertense and normotense subjects from San Luis (Argentina) by mismatch PCR-RFLP analysis. Hypertense patients exhibited significant increases in lipid related values and body mass index. The frequency of occurrence of the C1166 allele was higher among patients with hypertension (0.19) than in the control group (0.06). No significant association was found between this polymorphism and essential hypertension in the study population, although the AC genotype prevalence was higher in patients with hypertension and positive family history of hypertension (32%) than in control subjects (12%). Patients with the A1166C polymorphism exhibited higher levels of serum total cholesterol, LDL-cholesterol and BMI than in control subjects. Taken together the genotype and biochemical parameters and considering the restrictive selection criteria used, the present results suggest a correlation between AT1 A1166C gene polymorphism and risk of cardiovascular disease.(AU)

Autoradiographic localization of angiotensin II receptors in developing rat cerebellum and brainstem.

The role of Angiotensin II (Ang II) as a growth promoting or modulating factor has recently become a field of intensive research. A central issue in developmental neurobiology is the understanding of mechanisms governing the formation of spatially ordered connections. In this study, we show the localization of Ang II receptor subtypes by autoradiography in 2-week-old rat hindbrains confronting these data with membrane binding assays. Competition studies done on membrane preparations evidence no major changes on the relative affinities for both receptor subtypes between 2-week-old and adult rat tissues. By autoradiography, we found that all the areas (1-10) of the 2-week-old cerebellum showed both receptor subtypes present in complementary adjacent layers. Areas expressing a high level of AT2 receptors follow: inferior colicullus (IC), dorso tegmental nucleus, central (DTgC), subcoeruleus, alpha, sensory root of the trigeminal nerve, principal sensory root trigeminal nucleus (Pr5, Pr5VL) supragenual nucleus, genu facial nerve, facial nucleus, cerebellar peduncles, vestibular and lateral nuclei. Spinal trigeminal, (oral) and Raphe nuclei express AT1 receptor subtype. The high level of Ang II AT2 receptors present in the cerebellar peduncles might have a meaning on the establishment of the olivo-cerebellar connection. The high expression of Ang II AT2 receptors on 2-week-old rat hindbrains, a critical age on development, as well as its disappearance in the adult, strongly suggests a probable role of these receptors in cell migration and neuronal synaptogenesis.