摘要:

The effects of changes in Paco2on the circulation are complex, involving local vasodilation, vasodilation mediated by the pulmonary inflation reflex, and vasoconstriction due to effects on central vasomotor centers and peripheral chemoreceptors. One might anticipate that some or all of these might differ between the fetusin uteroand the newborn. Distribution of cardiac output was measured in unanesthetized fetal (n = 6) and newborn (n = 7) sheep, using the radioactive microsphere technique. Paco2rose from 44 to 70 (fetus) and 38 to 60 torr (newborn) with the addition of CO2to room air. In the fetus, there were significant increases in central nervous system (CNS), diaphragm, and lung blood flows. No organ showed a significant decrease in flow. Local vasodilation by CO2was the likely cause of the increased flow to CNS. The large increase in pulmonary blood flow was most likely due to the associated rise in fetal Pao2(23 to 28 torr) that accompanied respiratory acidosis and the presence of fetal breathing movements. The rise in diaphragmatic blood flow was likely the result of fetal breathing. In the newborn, CNS and diaphragm flows rose, but unlike the fetus, spleen and stomach flows decreased. These decreased flows in the hypercapnic newborn may have been due to stimulation of either central vasomotor centers or peripheral chemoreceptors.

ISSN:0031-3998    

出版商:OVID    

年代:1984

数据来源: OVID

摘要:

Placental blood flow was measured with the aid of radioactive microspheres, in normal (N) and manifest diabetic (MD) rats, and related to fetal body growth and incidence of congenital malformations. The total blood flow in the placentae of the MD rats was decreased to about one-half of the normal flow on gestational days 20 and 22. The placentae of the MD offspring were enlarged, whereas the fetuses in this group were smaller than normal. Thus, the placental blood flowper placental weightwas drastically decreased in the MD fetuses on both days 20 and 22. In contrast, the placental blood flowper fetal weightwas not different in the N and MD groups on gestational day 20 whereas it was decreased in the MD offspring on gestational day 22. Placental blood flow in the malformed fetuses of the MD group did not differ significantly from that in the nonmalformed MD fetuses.

ISSN:0031-3998    

出版商:OVID    

年代:1984

数据来源: OVID

摘要:

Venous blood was obtained from 100 consecutive and unselected Saudi Arabian mothers and their neonates within 48 h after delivery. Plasma levels of 25-hydroxyvitamin D (25-OHD) and total calcium were measured in paired samples. Fifty-nine mothers and 70 neonates had subnormal (less than 10 ng/ml) 25-OHD levels. Plasma Ca concentrations were low in 61% of the mothers and 59% of the newborns consisting of 10 preterm and 38 full term babies. There were significant correlation between the plasma levels of maternal and neonatal 25-OHD (r = 0.54; P = 0.0001), maternal 25-OHD and Ca (r = −0.22; P = 0.03), neonatal 25-OHD and Ca (r = −0.28; P = 0.0009), and maternal and neonatal calcium levels (r = 0.46; P = 0.0001). Nevertheless, maternal 25-OHD was not invariably higher than that in the infant. Normocalcemia was observed in 29 neonates and 26 mothers (20 mother/baby pairs) in the presence of subnormal maternal 25-OHD. Twenty babies and 16 mothers including nine mother/baby pairs had hypocalcemia in the presence of normal levels of 25-OHD. This indicates that vitamin D plays a crucial, but not exclusive, role in calcium homeostasis during pregnancy.This study revealed that vitamin D deficiency is very prevalent during pregnancy in Saudi Arabia. It also showed that asymptomatic hypocalcemia in full term babies is far commoner than is generally appreciated. It is considered that vitamin D deficiency is primarily due to lack of exposure to sunlight. Encouragement to obtain sunlight exposure and fortification of food are the only alternative measures.

ISSN:0031-3998    

出版商:OVID    

年代:1984

数据来源: OVID

摘要:

This paper describes a retrospective evaluation of the course of renal bone disease in 14 children undergoing treatment with continuous ambulatory peritoneal dialysis (CAPD) for an average of 11.9 ± 1.5 months (mean ± SE). The patients were divided in two groups according to the changes in serum alkaline phosphatase activity during the period of observation: five patients had alkaline phosphatase activity that decreased or was relatively stable (group I), and nine patients exhibited a rising serum alkaline phosphatase activity (group II). Serial radiological examinations showed adequate control of renal osteodystrophy in the patients of group I, whereas the patients of group II had no improvement or worsening of their bone disease. Group I had higher serum calcium and lower parathyroid hormone levels than group II at the end of period of observation despite similar dosage of vitamin D metabolite. The progression of bone disease was not related to the duration of CAPD or type of previous treatment for end stage renal disease.The observation that the radiological manifestations of secondary hyperparathyroidism were prevented in patients whose serum calcium levels were frequently above 2.62 mmol/liter (group I) while serum calcium levels between 2.25 and 2.50 mmol/liter in group II patients failed to lead to regression of secondary hyperparathyroidism is consistent with the existence of altered “setpoint” regulation of the parathyroid gland in children undergoing CAPD.

ISSN:0031-3998    

出版商:OVID    

年代:1984

数据来源: OVID

摘要:

Total parenteral nutrition solutions supplemented with cysteine-HCl (S-TPN, 0.8 mmol/kg/day) were infused into beagle pups from day 10 of life to day 20 (n = 6). Another group of pups received unsupplemented TPN solutions (US-TPN) (n = 6). Fluid, protein, and energy intake from nonprotein sources were similar in both groups. Data from these two groups were compared and similar measurements in normally suckled pups were also compared with the two TPN groups (n = 6).There were significant differences in the rate of weight gain between the pups that received TPN and the pups that were suckled (P > 0.01). Weight gain, hepatic DNA and protein concentrations, and cerebral DNA and protein concentrations in the pups that received TPN supplemented with cysteine were not different from similar measurements in pups that received unsupplemented TPN. Plasma total cyst(e)ine (Cyst(e)ine refers to the mixture in any proportion of the sulfhydryl (cysteine) and the disulfide (cystine) forms of this compound) concentrations in the cysteine-supplemented pups (7.9 ± 1.2 μ/DL, x ± SD) were significantly greater than in the unsupplemented pups (4.9 ± 1.8 μmol/DL). Hepatic glutathione concentrations in the supplemented pups (583 ± 85 μmol/100 g liver) were also significantly greater than in the unsupplemented pups (392 ± 113 μmol/100 g liver). These data suggest that the supplementation of TPN solutions with cysteine, even in an animal enzymatically capable of cysteine synthesis, has significant effects on glutathione synthesis.

ISSN:0031-3998    

出版商:OVID    

年代:1984

数据来源: OVID

摘要:

To evaluate the role of immunologic mechanisms in one specific syndrome of food intolerance in infants, food protein-induced enterocolitis, we measured class-specific serum antibodies to three food proteins, ovalbumin, soy, and cow milk, prior to diagnostic food challenges in 18 infants suspected to have this syndrome. Infants with positive challenge reactions to egg, soy, or cow milk had 5–10 times higher levels of IgA antibody directed against that food than did the infants with negative challenges. Levels of IgG antibody to soy and egg were also significantly higher (greater than 10-fold) in infants with positive challenge responses. There was no significant difference in levels of IgM food antibodies between the two groups. IgA anti-soy antibody levels rose in all 12 infants tested 2–10 weeks after a single soy feeding (challenge). However, IgM anti-soy antibody increased in the five infants who had a negative response to the challenge feeding and decreased in those seven with a positive response. The difference between the two groups was statistically significant (P > 0.01). Some correlation existed (r = −0.68) between the increase in IgA anti-soy antibody and the decrease in IgM anti-soy antibody for infants with positive soy challenges. Although a pathogenic role for these antibodies is not proven, the findings suggest an altered immunologic response to ingestion of food antigens in infants with food protein-induced enterocolitis.

ISSN:0031-3998    

出版商:OVID    

年代:1984

数据来源: OVID

摘要:

To study the production of proaggregatory thromboxane A2(TxA2) by fetal and neonatal platelets, blood specimens were collected from umbilical cords immediately after delivery at term (n = 22), from newborn infants during the first 10 days of life (n = 85), from infants between 1 and 3 months of age (n = 14), and from healthy adults (n = 18). The blood samples were allowed to clot spontaneously at +37±C for 60 min, and the concentrations of thromboxane B2(TxB2), a stable metabolite of TxA2, in the sera were measured by radioimmunoassay and expressed as nanograms of TxB2/106platelets.Platelet TxB2generation in term infants at the age of 1 day (1.344 ± 0.253 ng/106platelets, mean ± SE, n = 9) was higher than that in cord blood (0.634 ± 0.042 ng/106platelets, n = 22), or in infants of 1–3 months of age (0.881 ± 0.099 ng/106platelets, n = 14), or in adults (0.869 ± 0.062 ng/106platelets, n = 18). Increase in TxB2generation following birth was seen already at the age of 1 h (1.076 ± 0.114 ng/106platelets, n = 9). TxB2synthesis in preterm infants (1.032 ± 0.136 ng/106platelets, n = 10) did not differ from that in term infants on the 1st day of life, and idiopathic respiratory distress syndrome had no effect on it (1.029 ± 0.079 ng/106platelets, n = 19). Severe birth asphyxia was accompanied by reduced TxB2formation (0.564 ± 0.201 ng/ 106platelets, n = 7).The mode of delivery, the birth weight, and the sex of the infants were not related to TxB2production on the 1st day of life. Neither maternal pre-eclampsia nor epidural analgesia during labor affected neonatal TXB2generation. The bleeding time also did not correlate with TxB2formation. It is suggested that a rapid, but transient stimulation in TxA2synthesis after birth may contribute to the neonatal adaptation of vascular platelet function.

ISSN:0031-3998    

出版商:OVID    

年代:1984

数据来源: OVID

摘要:

A double-label, double-substrate incubation technique has been developed and used to study the conversion of progesterone to testosterone in testes extracts from incompletely virilized males. The procedure involves separation of the microsomes from a testicular homogenate, incubating the microsomes with 1 μ [7–3H]progesterone, 1 μ 17-hydroxyl4-14Clprogesterone, and 0.25 mM NADPH in pH 7.4 phosphate buffer at 37±C. Steroid precursors and products are separated by column chromatography on Sephadex LH-20 with a solvent system of isoctane:ethyl acetate:methanol (4:1:1 by volume). These procedures can be completed in 2 days, and thus the method represents an improvement in time, reproducibility, and simplicity when compared to techniques based on thin layer or paper chromatography.The method has been used to distinguish the biochemical abnormality in three cases with XY sex chromatin, posterior labial fusion, clitoromegaly, and hypospadias. The abnormalities identified were: Case 1, no defect in testosterone synthesis (probable androgen insensitivity); Case 2, 17-ketosteroid reductase deficiency; and Case 3, steroid-17,20-lyase deficiency.

ISSN:0031-3998    

出版商:OVID    

年代:1984

数据来源: OVID

摘要:

The syndrome of hypoxemia-related myocardial dysfunction in the newborn is generally associated with severe intrapartum asphyxia. We investigated the changes in total and regional distribution of myocardial blood flow (MBF) that occur during asphyxia and the factors that regulate MBF, in the chronically prepared, near term, fetal lamb. Studies were done in the awake, physiologically stable state 36–72 h after surgical preparation.In uteroasphyxia was produced by partial cord occlusion and blood flow to fetal organs was measured by the radioactive microsphere technique. A complete set of control measurements was made, and then an occlusion loop was inflated to partially occlude the umbilical vessels. After 30–60 min of partial occlusion, all measurements were repeated. The third set of measurements was made after release of the occlusion loop. Six animals were studied and 17 sets of measurements obtained.Partial umbilical cord constriction produced a progressive asphyxia and acidosis. Cardiac output was severely depressed, although the increase in percentage of cardiac output directed to the myocardium (%F) was very significant. Release resulted in improved cardiac output and O2and CO2exchange, although the metabolic acidosis was worse. No change occurred in the intra-myocardial distribution of MBF during asphyxia or recovery. Total MBF was not significantly increased during asphyxia.Multiple linear regression analysis indicated that arterial oxygen saturation (SaO2) and heart rate were statistically significant predictor variables for absolute MBF, accounting for about 45% of the variation in MBF. Further analysis determined that mean arterial blood pressure, pH, Po2, and Sao2were all statistically significant univariate predictors of MBF as %F, but only Sao2was a statistically significant multivariate predictor, accounting for about 82% of the variation in %F.We conclude that redistribution of a reduced cardiac output during cord occlusion is a major profective mechanism to maintain perfusion of vital organs. This redistribution is due in part to obstruction of placental blood flow, and probably also in part to chemoreceptor mediated circulatory reflexes, via O2receptors. No intramyocardial redistribution of coronary perfusion was observed during asphyxia; thus, this study provides no evidence for regional myocardial ischemia as a complication of severe intrapartum asphyxia.

ISSN:0031-3998    

出版商:OVID    

年代:1984

数据来源: OVID

摘要:

The glycosylated hemoglobin (glyco Hb) and the glycoprotein of the plasma were determined using affinity chromatographic techniques in cord blood and maternal blood of normal (Group I), White's Class A diabetic (Group II), and insulin-dependent diabetic (Group III) mothers. The results revealed significant increase of glyco Hb (P< 0.005) and glycoprotein (P< 0.005) in the newborns of Group III mothers in comparison to those of Group I. The glyco Hb of maternal blood in, this group also showed significant increase (P< 0.005) while the increase in Hb A, and plasma glycoprotein were nonsignificant. AH values for cord blood and maternal blood of White's Class A diabetics revealed no significant change from the normal group. We conclude that the fetuses of insulin-dependent diabetic mothers are hyperglycemicin utero.

ISSN:0031-3998    

出版商:OVID    

年代:1984

数据来源: OVID