摘要:

Meconium ileus and pancreatic changes, as described in cystic fibrosis, were found, at autopsy, in a series of six infants who received prolonged neonatal intensive care for prematurity. Cystic fibrosis had not been suspected clinically. These pathological findings are so frequent in sick premature infants, amounting to 12% of all neonatal autopsies conducted over a period of 2 yr in our unit, that we question their specificity for cystic fibrosis and suggest they may be a manifestation of disordered physiology in the severely ill neonate. (Pediatr Res 20: 536-541,1986)

ISSN:0031-3998    

出版商:OVID    

年代:1986

数据来源: OVID

摘要:

Rates of utilization of glucose, acetate, and lactate and activities of selected enzymes were determined in vitro to characterize the nature of lipogenesis and metabolite utilization in perirenal adipose tissue from 6- to 7- month old fetal and 3- to 4-h-old unsuckled newborn calves. Contribution of the pentose phosphate cycle to glucose metabolism was estimated using specifically labeled glucose. Rates of fatty acid synthesis from all three substrates and oxidation of glucose were much greater in fetal than in newborn adipose tissue. In fetal adipose tissue, acetate and lactate were major sources of carbon for fatty acid synthesis; glucose functioned mainly by metabolism via the pentose phosphate cycle to provide reducing equivalents for fatty acid synthesis and by incorporation into glyceride glycerol for fatty acid esterification. Pentose phosphate cycle contributed 58 and 12% to glucose metabolism in adipose tissue of fetal and newborn calves, respectively. Adipose tissue metabolism of newborn calves was characterized by greatly depressed rates of fatty acid synthesis despite high enzyme activities and elevated rates of glyceride glycerol synthesis. (Pediatr Res 20: 542-544,1986)

ISSN:0031-3998    

出版商:OVID    

年代:1986

数据来源: OVID

摘要:

Because of current interest in use of a combination of glucocorticoid and thyroid hormones for prevention of respiratory distress syndrome we examined the effects of dexamethasone and triiodothyronine (T3), alone and in combination, on glycogen content and rates of fatty acid and phosphatidylcholine synthesis in fetal rat lung. The hormones were administered to the mothers on the 2 days before delivery on days 17-22 of gestation. Both hormones increased the rate of choline incorporation into phosphatidylcholine, an index of surfactant synthesis, on day 20 just prior to the normal developmental surge but had no effect on this parameter on days 19, 21, or 22. There is a developmental increase in lung glycogen on days 17-20 with a decrease thereafter and a developmental increase in the rate of fatty acid synthesis between days 20 and 21. The increases in glycogen content and fatty acid synthesis were accelerated by dexamethasone and prevented by T3and when the hormones were administered together T3antagonized the stimulatory effects of dexamethasone on these parameters. Both dexamethasone and T3accelerated the normal developmental decrease in lung glycogen later in gestation and the effects of the two hormones on this parameter were additive. The combination of dexamethasone and T3led to significantly smaller fetuses and increased mortality late in gestation. These data show that glucocorticoid and thyroid hormones have opposite as well as common effects on parameters of fetal lung maturation. Although the relationship between changes in lung glycogen or fatty acid synthesis and surfactant production are not known the combination of hormones may be beneficial at certain gestational ages but harmful at others. (Pediatr Res 20: 545-550,1986)

ISSN:0031-3998    

出版商:OVID    

年代:1986

数据来源: OVID

摘要:

Plasma and urinary zinc levels were examined in 6 infants with fetal alcohol syndrome to determine whether zinc deficiency, if present in fetal alcohol syndrome patients, is secondary to an increased urinary zinc excretion. Six infants born to nonalcoholic mothers served as controls. There was no significant difference in creatinine clearance, urine flow rate, or plasma albumin concentrations between the two groups. Plasma concentrations of zinc were significantly lower in fetal alcohol syndrome patients (62.5 ± 2.8 μg/dl) in comparison to controls (71 ± 1.8 μg/dl), (p=0.0001). Urinary excretion of zinc in fetal alcohol syndrome patients averaged 646 ±125 μg/24 h, significantly higher than in control subjects (76.6 ± 22 μg/24 h), (p=0.0001). Thus (1) lower plasma zinc levels are present in infants with fetal alcohol syndrome and (2) increased urinary zinc excretion appears to be responsible for decreased plasma zinc concentrations. (Pediatr Res 20: 551-554,1986)

ISSN:0031-3998    

出版商:OVID    

年代:1986

数据来源: OVID

ISSN:0031-3998    

出版商:OVID    

年代:1986

数据来源: OVID

摘要:

Escherichia coli which elaborate heat stable enterotoxin (ST) are a major cause of endemic diarrhea in infants. The reason(s) for this increased susceptibility of infants to ST-mediated diarrhea is unknown. We investigated the possibility that the immature (14 and 21 day old) rat small intestine is more sensitive to ST than is the adult. Initially we found there was a 600-fold increased jejunal sensitivity to ST in the immature animals as measured by dose required for half maximal secretion. Also there was a greater jejunal secretory response in the immature animals (14≤21 days old>adult). To determine the cause for this increased sensitivity and secretory response to ST, we examined: 1) binding characteristics of125I-ST to brush border membrane (BBM) receptors and 2) membrane bound guanylate cyclase activation by ST in both immature and adult rats. Our findings demonstrate that more ST receptors are present in jejunal BBM from 14- and 21-dayold rats than in jejunal BBM from adult rats (2.34 ± 0.18, 2.85 ± 0.82, and 0.79 ± 0.13 X 1012receptors/mg BBM protein, respectively), while the affinity of the BBM receptor for ST is similar at all three ages in both jejunum and ileum. Furthermore, both the jejunum and ileum of the rats of all three ages revealed an equal sensitivity of guanylate cyclase to activation by ST. These findings suggest that the increased number of jejunal receptors in the immature rat may, in part, explain the increased sensitivity and secretory response observed in vivo.

ISSN:0031-3998    

出版商:OVID    

年代:1986

数据来源: OVID

摘要:

Total body electrical conductivity (TOBEC) has been introduced as a rapid, safe, and noninvasive method suitable for the estimation of fat-free mass. The instrument (EMME or TOBEC) operates on the principle that organisms placed in an electromagnetic field perturb the field to a degree that depends on the amount and volume of distribution of electrolytes present. A study was designed to measure body composition in infants by the TOBEC method and to compare the results with those obtained using the isotope dilution technique. Sixteen infants (age range, 2 days to 9.7 months; weight range, 2 to 8.7 kg) were enrolled. Total body water (TBW) was determined by the isotope dilution technique using H218O. There was a good correlation between the natural logarithm of the TOBEC number and TBW, with a linear correlation coefficient of 0.949. The fat-free body mass of the infants was calculated by TBW (fat-free body mass=/0.082) and by the TOBEC method using the standard previously derived from mature rabbits. TBW measurements by H218O dilution appeared to overestimate fat-free mass which was greater than TBW in five of the 16 infants. Measured by the TOBEC method, fat-free mass ranged from 51 to 91% of total body weight. The TOBEC method is highly suitable for use with human infants and appears to determine body composition as accurately as other available methods.

ISSN:0031-3998    

出版商:OVID    

年代:1986

数据来源: OVID

摘要:

A pivotal intermediate in prostaglandin (PG) biosynthesis is the endoperoxide PGH2. This endoperoxide is capable of eliciting direct responses in biological systems without undergoing conversion to other PGs. Effects of PGH2 include stimulation of platelet aggregation and vascular smooth muscle contraction in vitro; injections of PGH2 in vivo cause increases in pulmonary arterial pressure. The response of the pulmonary vasculature of perinatal lambs to PGH2 was measured using an in situ pumpperfused left lower lung preparation. Intrapulmonary injections of PGH2 (0.24-0.61 μg/kg) into six unventilated fetal lambs (0.93-0.97 gestation) produced decreases in pulmonary vascular resistance (PVR) of 10-21%. The fall in PVR was rapid in onset, reached a peak at 10 s after injection, and returned to baseline within 35S. Following ventilation (FIO2=0.21) of fetal lambs, injections of PGH2 (0.24-0.61 μg/kg) caused increases in PVR (ave increase=50% over control PVR). The pulmonary pressor re-sponse to PGH2 in ventilated fetal lambs was depressed almost 50% by inhibition of thromboxane synthetase. Injections of a “heat-inactivated” PGH2 did not affect PVR in ventilated fetuses. We did not observe any effects on systemic blood pressure or heart rate of intrapulmonary arterial injections of PGH2. These findings suggest a me-tabolism of PGH2 to dilator PGsbefore ventilation and constrictor PGsand thromboxanes after ventilation, and or direct effects of PGH2 on vascular smooth muscle that are dependent on existing vascular tone.

ISSN:0031-3998    

出版商:OVID    

年代:1986

数据来源: OVID

摘要:

Using auditory brainstem response audiometry, we evaluated 34 congenital hypothyroidism children under thyroid hormone therapy and 24 age- and sex-matched controls between 5 and 12 yr of age. Two main auditory brainstem response abnormalities were encountered: first, prolonged wave I latencies, secondary to a peripheral impairment, were found in seven congenital hypothyroidism children (20%): three of these showed signs of serious otitis media, unilaterally in two and bilaterally in the other, at the time of the evaluation. Second, shortened I-V interpeak latencies were observed in 10 children (29%). No correlation was found between the interpeak latencies and the L-thyroxine serum values at the time of the test or just prior to treatment initiation. Also, there was no correlation with estimated bone age at treatment initiation or with the Griffiths global mental development quotients assessed at 5 yr of age. These preliminary results suggest a significant incidence of auditory brainstem response abnormalities in treated hypothyroid children.

ISSN:0031-3998    

出版商:OVID    

年代:1986

数据来源: OVID

摘要:

Plasma selenium concentration and glutathione peroxidase activity in red blood cells were determined in subjects from different age groups. The selenium level (mean ± SD) found in infancy (0 to 6 months) was 2 ± 0.6 /μg/dl, with the lowest value of 1 /μg/dl observed in a 4- month-old infant. These levels were significantly lower (p<0.001) than the value of 9.5 ± 1.1 /μg/dl found in the adult group and 7.7 ± 1.3 μg/dl found in the group of older children (2 to 15 yr). Younger children (6 to 24 months of age) had intermediate levels of 5 ± 1.2 /μg/dl. When the data were plotted on a logarithmic scale as a function of age, the figure shows clearly that the plasma selenium levels increase steadily with age throughout life after an initial drop at 60 to 90 days. There was a satisfactory correlation between the plasma selenium concentration and the enzyme glutathione peroxidase activity in the red blood cells (Spearman's ρ=0.45, p<0.005). Although very low selenium values were observed, the enzyme glutathione peroxidase activity remained above 10 U/g hemoglobin (with only one exception) in all patients.

ISSN:0031-3998    

出版商:OVID    

年代:1986

数据来源: OVID