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Fuchs and Fuchs: Fetal uptake of phospate in prolonged gestation in rabbits
October l5, 1%c
1120 Selected abstracts
lation between the concentration of hydrocortisone and that of plasma protein, since the fetal protein concentrations are restricted to a too limited range. Considering that hydrocortisone is present in a reversible binding to plasma protein and that the freely diffusible fraction of hydrocortisone readily passes the placenta, the theoretical expectation was a diffusion equilibrium adjusting itself between the diffusible fractions in the fetal and maternal blood and a binding of hydrocortisone in a quantity corresponding to the fetal plasma protein level. None of the findings in this study militates against the hypothesis that the lower concentrations of hydrocortisone in cord blood than in matPrnal blood are due to the binding of hydrocortisone by protein. Robert E. L. Nesbitt, .fr. Leyssac: Hydrocortisone in Fetal Plasma Fol· lowing Intravenous Administration of Hydrocortisone to the Mother, Part II, p. 181. Following continuous infusion of hydrocortisone to pregnant women prior to spontaneous abortion, the plasma level of hydrocortisone was analyzed in blood specimens drawn at practically the same time from the mother, the umbilical vein, and the left heart of the fetus. The concentration in the cardiac blood proved to be significantly lower than that in the umbilical vein blood in four experiments. It is concluded that the fetus is able t<{. eliminate hydrocortisone at a metabolic rate more rapid than in adults. This rapid elimination must presumably be attributed to the relatively large fetal liver. In two experiments, where the fetuses were anoxic, the hydrocortisone level in the mixed cardiac blood was as high as that in the umbilical vein. Whether the relatively high concentration in the cardiac blood was due to active secretion of hydrocortisone in the fetus or to a reduced turnover in the fetal liver damaged by anoxia is discussed. Recent animal experiments concerning the fetal pituitary-adrenal activity are highly in favor of the view of propounding an active interplay even in antenatal life. It has not yet been shown clearly, however, whether the fetal adrenals are in fact capable of produc· ing hydrocortisone. The concentration of hydrocortisone in the cord blood does not reflect fetal adrenal activity, since the higher concentrations in the blood from the umbilical vein than in blood from the umbilical artery or mixed cardiac
Am.
blood in normal deliveries can by the transplacental passage from the maternal to the fetal Robert
J.
Ob~t.
& r;ynN,
be explained only of hydrocortisone organism. E. L. Nesbitt, Jr.
Fuchs and Fuchs: Fetal Uptake of Phosphate in Prolonged Gestation in Rabbits, p. 281. The transfer of phosphate from mother to fetus in prolonged gestation was studied in rabbits with the aid of radioactive phosphorus. Pregnancy was prolonged with daily injections of 5 mg. progesterone. The previous observations of increased fetal mortality after term w~re confirmed. Fetal phosphorus concentration, which increases during normal gestation, does not increase further after term, indicating a relative placental insufficiency with regard to phosphorus. After intrauterine death, however, the placentas remain alive, at least for some time, and continue to accumulate phosphorus. This indicates that the removal of phosphate from the maternal blood hy the placenta is independent of the fetus. These experiments show that inorganic phosphate is transferred from the maternal to the fetal blood against a concentration gradient. This requires an active transport mechanism which must be localized to the chorionic cells, probably at their boundary toward the intervillous space. In the placenta a pool of phosphorus is formed, from which the fetus is supplied. Robert E. L. Nesbitt, Jr. Kullander and Kallen: Tissue Culture Studies on Human Ovarian Tumours With Special Reference to Influence of Estrogens and Androgens on Growth Rate, p. 391. Tissue culture studies were made of 14 human ovarian tumors, both benign and malignant. Their outgrowth patterns were described and the possible influence of steroids on their growth rate was studied. The benign tumors grew with a dominating epithelial growth pattern; the malignant ones, especially poorly differentiated ones, grew with a pseudoreticular and reticular pattern. Eight of the tumors were tested with estrone or androsterone or both. Four showed signs of estrogen stimulation, one of androgen stimulation also. Three of the reacting tumors were benign. Steroids did not result in apparent arrest of growth of cells in any case. The authors stressed that a possible way of judging endocrine responsiveness of ovarian tumors is to be found in tissue culture methods. Robert E. L. Nesbitt, Jr.
1120 Selected abstracts
lation between the concentration of hydrocortisone and that of plasma protein, since the fetal protein concentrations are restricted to a too limited range. Considering that hydrocortisone is present in a reversible binding to plasma protein and that the freely diffusible fraction of hydrocortisone readily passes the placenta, the theoretical expectation was a diffusion equilibrium adjusting itself between the diffusible fractions in the fetal and maternal blood and a binding of hydrocortisone in a quantity corresponding to the fetal plasma protein level. None of the findings in this study militates against the hypothesis that the lower concentrations of hydrocortisone in cord blood than in matPrnal blood are due to the binding of hydrocortisone by protein. Robert E. L. Nesbitt, .fr. Leyssac: Hydrocortisone in Fetal Plasma Fol· lowing Intravenous Administration of Hydrocortisone to the Mother, Part II, p. 181. Following continuous infusion of hydrocortisone to pregnant women prior to spontaneous abortion, the plasma level of hydrocortisone was analyzed in blood specimens drawn at practically the same time from the mother, the umbilical vein, and the left heart of the fetus. The concentration in the cardiac blood proved to be significantly lower than that in the umbilical vein blood in four experiments. It is concluded that the fetus is able t<{. eliminate hydrocortisone at a metabolic rate more rapid than in adults. This rapid elimination must presumably be attributed to the relatively large fetal liver. In two experiments, where the fetuses were anoxic, the hydrocortisone level in the mixed cardiac blood was as high as that in the umbilical vein. Whether the relatively high concentration in the cardiac blood was due to active secretion of hydrocortisone in the fetus or to a reduced turnover in the fetal liver damaged by anoxia is discussed. Recent animal experiments concerning the fetal pituitary-adrenal activity are highly in favor of the view of propounding an active interplay even in antenatal life. It has not yet been shown clearly, however, whether the fetal adrenals are in fact capable of produc· ing hydrocortisone. The concentration of hydrocortisone in the cord blood does not reflect fetal adrenal activity, since the higher concentrations in the blood from the umbilical vein than in blood from the umbilical artery or mixed cardiac
Am.
blood in normal deliveries can by the transplacental passage from the maternal to the fetal Robert
J.
Ob~t.
& r;ynN,
be explained only of hydrocortisone organism. E. L. Nesbitt, Jr.
Fuchs and Fuchs: Fetal Uptake of Phosphate in Prolonged Gestation in Rabbits, p. 281. The transfer of phosphate from mother to fetus in prolonged gestation was studied in rabbits with the aid of radioactive phosphorus. Pregnancy was prolonged with daily injections of 5 mg. progesterone. The previous observations of increased fetal mortality after term w~re confirmed. Fetal phosphorus concentration, which increases during normal gestation, does not increase further after term, indicating a relative placental insufficiency with regard to phosphorus. After intrauterine death, however, the placentas remain alive, at least for some time, and continue to accumulate phosphorus. This indicates that the removal of phosphate from the maternal blood hy the placenta is independent of the fetus. These experiments show that inorganic phosphate is transferred from the maternal to the fetal blood against a concentration gradient. This requires an active transport mechanism which must be localized to the chorionic cells, probably at their boundary toward the intervillous space. In the placenta a pool of phosphorus is formed, from which the fetus is supplied. Robert E. L. Nesbitt, Jr. Kullander and Kallen: Tissue Culture Studies on Human Ovarian Tumours With Special Reference to Influence of Estrogens and Androgens on Growth Rate, p. 391. Tissue culture studies were made of 14 human ovarian tumors, both benign and malignant. Their outgrowth patterns were described and the possible influence of steroids on their growth rate was studied. The benign tumors grew with a dominating epithelial growth pattern; the malignant ones, especially poorly differentiated ones, grew with a pseudoreticular and reticular pattern. Eight of the tumors were tested with estrone or androsterone or both. Four showed signs of estrogen stimulation, one of androgen stimulation also. Three of the reacting tumors were benign. Steroids did not result in apparent arrest of growth of cells in any case. The authors stressed that a possible way of judging endocrine responsiveness of ovarian tumors is to be found in tissue culture methods. Robert E. L. Nesbitt, Jr.