Estudio del metabolismo y regulación del hierro entre el recién nacido y su madre al momento del nacimiento / Iron metabolism and regulation study between infant newborn and mother in the moment of birth

Estudiar el metabolismo y regulación del hierro en Recién Nacidos (RN) y sus madres (M). Población: 56 madres y sus RN, atendidos en Hospital "José G. Hernández", Catia, Caracas. A las madres y RN se determinó hemoglobina (Hb), hierro sérico (FeS), por ciento de Saturación de Transferrina y Ferritina sérica. Las madres y RN se agruparon según niveles de FeS en M Bajo Hierro (MBH), M Normo Hierro (MNH) y M Alto Hierro (MAH). Resultados madres: los niveles de FeS son diferentes estadísticamente entre ellas. Las concentraciones de Hb no muestran diferencias. La transferrina monoférrica predomina en las M. Resultados RN: los niveles de FeS de RN-MAH son mayores y significativos a los RN-MBH y RN-MNH. Valores de FeS RN son superiores a las M. La forma diférrica de la transferrina predomina en RN. Conclusión: La forma monoférrica en M y diférrica en RN limita la competencia por el FeS, permitiendo concentrarse en los depósitos del RN

1, 25-Dihydroxyvitamin D3 stimulates growth and inhibits calcitonin secretion in a human C cell carcinoma cell line

1,25-Dihydroxyvitamin D3 (1,25D3), calcitonin (CT) and parathyroid hormone are the major calcium-regulating hormones. In addition, 1,25D3 has been reported to be a modulator of cell growth and differentiation in many tissues. recently, a suppressive effect of 1,25D3 on CT secretion and synthesis in C cells was demonstrated in vivo and also in vitro, but there are no data about in effects on thyroid C cell growth. We investigated the effects of [3H]-1,25D3 on basal and stimulated CT secretion and on [3H]-thymidine incorporation, using a human medullary thyroid carcinoma cell line (TT cells). After a 4-day expossure to 1,25D3, TT cells showed a dose-dependent inhibition of basal CT secretion (64 per cento of value for the control group at 100 nM 1,25D3). calcium (3mM) plus K+ (50mM) greatly increased CT secretion in both the control and vitamin D-treated groups. However, in the cells preincubated with 1,25D3 the stimulated CT levels less than observed in controls. A dose-dependent increase in [3H]-thymidine incorporation (200 per cent of the value for the at 100 nM 1,25D3) and in cell number (150 per cent of the value for the control group at 100 nM 1,25D3 after 72h) was observed in the groups treated with 1,25D3. 24,25D3 had no effect on CT secretion or cell growth compared to the control group. These data show that 1,25D3 decreased basal and Ca2+-stimulated CT secretion, a specialized function of these cells, and stimulated their growth. Hence, in contrast to its effects on other cell lines, 1,25D3 appears to induce a dedifferentiation on TT cell