RESUMO
The reversibility of thyroid dysfunction in children with endemic cretinism treated with supplemental iodine is unknown. To study this question we conducted a five-month follow-up of 51 patients with cretinism (age 14 and below), who were randomly assigned to treatment (0.5 ml of intramuscular iodized oil) and control groups. The geometric mean initial serum level of thyrotropin (223 microU per milliliter; SD, 97 to 513) and the mean (+/- SD) initial serum level of thyroxine (1.0 +/- 1.2 micrograms per deciliter) indicated that all patients had severe hypothyroidism. Within one month after receiving the iodized oil, 13 of 14 of the younger patients (less than 4 years) and 1 of 9 of the older patients (4 to 14 years; P less than 0.001) had thyrotropin values below 20 microU per milliliter. Five months after treatment, the levels of thyrotropin had decreased and those of thyroxine had increased in all children, but greater changes occurred in the 13 younger patients than in the 14 older patients. The mean levels of thyrotropin were 2 microU per milliliter (SD, 0.6 to 6) vs. 38 microU per milliliter (SD, 11 to 132; P less than 0.001), and the mean (+/- SD) levels of thyroxine were 13.1 +/- 2.8 vs. 8.1 +/- 4.6 micrograms per deciliter (P less than 0.001). In the untreated group, 3 of the 9 younger patients and none of the 15 older patients recovered normal thyroid function within five months. We conclude that iodine supplementation restored a biochemically euthyroid state in all younger children with cretinism but only some of the older children. In addition, some younger patients became euthyroid without iodine supplementation.
Assuntos
Hipotireoidismo Congênito/tratamento farmacológico , Iodo/uso terapêutico , Adolescente , Fatores Etários , Criança , Pré-Escolar , Ensaios Clínicos como Assunto , Humanos , Hipotireoidismo/tratamento farmacológico , Injeções Intramusculares , Óleo Iodado/administração & dosagem , Tireotropina/sangue , Tiroxina/sangue , Tri-Iodotironina/sangueRESUMO
Eight strains of male rats (AUG, BN, LEW, LIS, WAG, F 344, LOU/M, DA) and 3 strains of female rats (LEW, F 344, KGH) were challenged with 15 X 10(4) trypomastigotes of the Tehuantepec strain of T. cruzi. Parasitemia and mortality were observed for 60 days. Varying degrees of susceptibility were demonstrated between strains: complete resistance (R), no parasitemia; low resistance (LR), mild parasitemia; and no resistance (NR), high parasitemia. The differences in susceptibility to T. cruzi, using inbred strains of rats, were unrelated to Rt-1 haplotype. However, the level of parasitemia and host survival are not necessarily related; both male and female F 344 hosts are susceptible (NR) to T. cruzi but only females survive.
Assuntos
Doença de Chagas/imunologia , Ratos Endogâmicos/genética , Doenças dos Roedores/imunologia , Trypanosoma cruzi/patogenicidade , Animais , Doença de Chagas/mortalidade , Suscetibilidade a Doenças , Feminino , Genes MHC da Classe II , Interações Hospedeiro-Parasita , Complexo Principal de Histocompatibilidade , Masculino , Ratos , Fatores Sexuais , Especificidade da EspécieRESUMO
Las ratas Fischer (F344) machos infectadas experimentalmente con diferentes cantidades de tripomastigotes sanguineos de la cepa Tehuantepec de Trypanosoma cruzi desarrollan un aumento progresivo de la parasitemia, seguida por la muerte de los animales en la fase aguda de la infeccion.Las curvas de parasitemia muestran un patron comun y la muerte de los animales ocurre en periodos definidos. En esta cepa de ratas fue posible inducir una proteccion contra la enfermedad aguda despues de inocularlas con epimastigotes vivos, de cultivo. No se produjeron parasitemias al examen directo, no obstante una infeccion subyacente fue detectada tras cultivar celulas del bazo de animales protegidos. En el suero de todos los animales se demostro la presencia de anticuerpos anti-T. cruzi y altos niveles de IgG2a
Assuntos
Masculino , Animais , Ratos , Anticorpos , Doença de Chagas , Trypanosoma cruziRESUMO
Las ratas Fischer (F344) machos infectadas experimentalmente con diferentes cantidades de tripomastigotes sanguineos de la cepa Tehuantepec de Trypanosoma cruzi desarrollan un aumento progresivo de la parasitemia, seguida por la muerte de los animales en la fase aguda de la infeccion.Las curvas de parasitemia muestran un patron comun y la muerte de los animales ocurre en periodos definidos. En esta cepa de ratas fue posible inducir una proteccion contra la enfermedad aguda despues de inocularlas con epimastigotes vivos, de cultivo. No se produjeron parasitemias al examen directo, no obstante una infeccion subyacente fue detectada tras cultivar celulas del bazo de animales protegidos. En el suero de todos los animales se demostro la presencia de anticuerpos anti-T. cruzi y altos niveles de IgG2a
