RESUMO
AIM: To determine the effect of grazing pasture that had a low selenium (Se) concentration on serum concentrations of triiodothyronine (T3) and thyroxine (T4), and erythrocyte glutathione peroxidase (GSH-Px) activity in dairy cows. METHODS: Forty pregnant Friesian cows were grazed on pasture that contained 0.03-0.04 ppm Se on a dry matter (DM) basis. Two months before parturition, 20 cows were randomly selected and treated with 1 mg Se/kg bodyweight subcutaneously, as barium selenate (Group Se-S). The other group (Se-D) was not supplemented. Blood samples were taken before supplementation (-60 days) and 30, 60, 90, 180 and 270 days after parturition, for determination of concentrations of T3 and T4 in serum, and GSH-Px activity in erythrocytes. RESULTS: Erythrocyte GSH-Px activity in the Se-D group was <60 U/g haemoglobin (Hb) throughout the experiment. Supplementation increased (p<0.05) activities to >130 U/g Hb throughout lactation. Mean serum concentrations of T4 in Se-D and Se-S cows increased from 23.7 (SEM 0.7) and 23.4 (SEM 0.8) nmol/L, respectively, in the prepartum period to 69.6 (SEM 0.1) and 67.6 (SEM 0.2) nmol/L, respectively, at 180 days of lactation (p<0.01), and no effect of Se supplementation was evident. Serum concentrations of T3 in Se-D cows decreased (p<0.05) from 1.6 (SEM 0.1) nmol/L prepartum to 1.0 (SEM 0.2) nmol/L at the beginning of lactation, and remained lower (p<0.05) than those in the Se-S cows which did not decrease after calving and ranged from 1.9 (SEM 0.1) to 2.4 (SEM 0.2) nmol/L throughout lactation. CONCLUSIONS: Serum T3 concentrations decreased during early lactation in unsupplemented cows grazing pastures low in Se (0.03-0.04 ppm) and both serum T3 and erythrocyte GSHPx activities were consistently lower throughout lactation compared with Se-supplemented cows. Se supplementation had no effect on serum T4 concentrations.
Assuntos
Ração Animal , Eritrócitos/efeitos dos fármacos , Glutationa Peroxidase/efeitos dos fármacos , Selênio/farmacologia , Tiroxina/efeitos dos fármacos , Tri-Iodotironina/efeitos dos fármacos , Criação de Animais Domésticos , Animais , Bovinos , Chile , Indústria de Laticínios , Eritrócitos/enzimologia , Feminino , Glutationa Peroxidase/metabolismo , Gravidez , Selênio/administração & dosagem , Selênio/análise , Tiroxina/sangue , Resultado do Tratamento , Tri-Iodotironina/sangueRESUMO
El cementoblastoma benigno o cementoma verdadero se describe como una lesión poco común que se presenta con mayor frecuencia en pacientes menores de 25 años no existiendo predilección por el sexo. La lesión es de crecimiento lento y puede causar expansión de las corticales del hueso asociadas, sin embargo es por lo general asintomática. Radiográficamente se observa una masa radioopaca, densa y circunscripta adherida a la raiz del diente. Se presenta un caso clínico de una pciente del sexo femenino, 31 años de edad, que consulta en el servicio de Cirugía Maxilofacial Hospital Carlos Van Buren, Valparaíso. Se realiza una revisión de la literatura, en relación a aspectos clínicos, radiográficos, histológicos, diagnóstico diferncial y alterantivas de tratamiento