Hyperthyroidism in rats is associated with increased oxidative stress. These animals also show abnormal renal hemodynamics and an attenuated pressure-diuresis-natriuresis (PDN) response. We analyzed the role of oxidative stress as a mediator of these alterations by examining acute effects of tempol, a superoxide dismutase mimetic. The effects of increasing bolus doses of tempol (25-150 micromol/kg) on mean arterial pressure (MAP), renal vascular resistance (RVR), and cortical (CBF) and medullary (MBF) blood flow were studied in control and thyroxine (T4)-treated rats. In another experiment, tempol was infused at 150 micromol.kg(-1).h(-1) to analyze its effects on the glomerular filtration rate (GFR) and on PDN response in these animals. Tempol dose dependently decreased MAP and RVR and increased CBF and MBF in control and T4-treated rats, but the T4 group showed a greater responsiveness to tempol in all of these variables. The highest dose of tempol decreased RVR by 13.5 +/- 2.1 and 5.5 +/- 1.2 mmHg.ml(-1).min(-1) in hyperthyroid (P < 0.01) and control rats, respectively. GFR was not changed by tempol in controls but was significantly increased in the hyperthyroid group. Tempol did not change the absolute or fractional PDN responses of controls but significantly improved those of hyperthyroid rats, although without attaining normal values. Tempol increased the slopes of the relationship between renal perfusion pressure and natriuresis (T4+tempol: 0.17 +/- 0.05; T4: 0.09 +/- 0.03 microeq.min(-1).g(-1).mmHg(-1); P < 0.05) and reduced 8-isoprostane excretion in hyperthyroid rats. These results show that antioxidant treatment with tempol improves renal hemodynamic variables and PDN response in hyperthyroid rats, indicating the participation of an increased oxidative stress in these mechanisms.
QUISTE CUTÁNEO CILIADO EN PIEL ESCROTAL. DESCRIPCIÓN DE UN CASO CON DISCUSIÓNPATOGÉNICA DE LA ENTIDAD El quiste cutáneo ciliado (QCC) es una lesión benigna muy infrecuente, que aparece predominantemente en extremidades inferiores de mujeres jóvenes. En varones es una lesión aún más rara. En esta nota se presenta un caso de quiste cutáneo ciliado en piel escrotal de un varón de 15 años, se describen características histológicas e inmunohistoquímicas, se revisa la bibliografía al respecto y se realiza una discusión patogénica de la entidad. Se plantea que el QCC puede ser en realidad un patrón morfológico que engloba varias entidades patogénicamente diferentes. Los datos aportados en nuestro caso apoyan la teoría de que al menos un grupo de QCC, y en especial los acaecidos en pacientes de sexo masculino, podrían tener su origen en la metaplasia ciliada de glándulas sudoríparas apocrinas. Palabras clave: Quiste cutáneo ciliado. Piel escrotal. Inmunohistoquímica-receptores hormonales. Patogénesis.
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