摘要:

SummaryThe concentration of total carnitine in human breast milk remained at a constant mean level near 62.9 range: 56.0–69.8/nmoles/ml during the first 21 days postpartum. The carnitine level fell significantly to 35.2 ± 1.26 nmoles/ml until the 40–50th day. The carnitine concentrations did not depend on the secreted volume of milk. In comparison, fresh and commercial pasteurized cow's milk contained 206.2 (range: 192–269) nmoles/ml and 160.0 (range: 158–200) nmoles/ml carnitine, respectively. In the sera of nursing mothers, the concentration of total carnitine was lower on the first day after delivery (27.2 ± 1.19 nmoles/ml) but returned to normal by the 21st day postpartum (38.8 ± 2.97 nmoles/ml).

ISSN:0031-3998    

出版商:OVID    

年代:1982

数据来源: OVID

摘要:

SummaryPrevious reports concerning children with Cockayne syndrome had described decreased T cell proliferative responses and renal anomalies which could be associated with immunologic disturbances. Herein, the thymic function was evaluated by measuring the serum level of thymic hormone. This serum level was found to be undetectable or decreased in seven cases of Cockayne syndrome. Active serum concentrations varied between 0 and 1/8, whereas normal children of the same age show activity in the range between 1/16 and 1/64. In contrast, T cell function, explored by phytohemagglutinin and Concavalin A responses, and mixed lymphocyte cultures was normal. Whether or not this premature sign of immunological aging is primary or secondary to other manifestations of the syndrome is still difficult to assess.

ISSN:0031-3998    

出版商:OVID    

年代:1982

数据来源: OVID

摘要:

SummaryHigh concentrations of ACTH are present in the neonatal circulation in response to birth stress. Since ACTH and β-lipotropin (βLPH) have a common precursor, and ACTH and β-endorphin (βEP) are released in parallel in stressful situations, we measured plasma levels of βLPH and βEP in the first 24 hours of life.Blood samples were taken from the umbilical cord at birth in 27 neonates, subdivided into four groups.A further blood sample was obtained from the jugular vein after 30 min in nine cases (group A), after 6 hours in six (group B), and after 12 hours in six (group C), and after 24 hours in six (group D).βLPH and βEP were measured by specific radioimmunoassays after silicic acid extraction of the plasma and Sephadex G-75 column chromatography.In cord plasma, the mean (±S.E.) βLPH concentrations (pg/ml) varied between 219.5 ± 84.5 (group D) and 241 ± 43.3 (group B), while those of βEP ranged between 70.2 ± 8.2 (group C) and 54.6 ± 14.4 (group D). The βLPH/βEP ratio on a molar basis ranged from 1.12 ± 0.73 (group A) to 1.37 ± 0.60 (group C).Plasma βLPH concentrations determined at 30 min were 199.1 ± 50.4, and these declined slightly in group C (after 12 hours: 168.2 ± 30.2), but only showed a significant fall after 24 hours (88.5 ± 27.0;P< 0.01 in comparison with the previous groups), reaching normal adult levels (71.7 ± 25.1).The pattern of βEP plasma levels (pg/ml) was very similar to that reported for βLPH. βEP plasma levels only showed a significant decrease after 24 hours (22.7 ± 8.9;P< 0.01) when compared to the 12-hour age group C. βEP concentrations at 30 min (76.1 ± 47.7), 6 hours (68.6 ± 29.3), and 12 hours (51.8 ± 18.1) of life did not differ significantly from those found in mixed cord blood and were constantly higher than normal adult levels [24.5 ± 12.3].Since the half-life of βLPH and βEP is respectively 45 and 37 min, the present data demonstrate that neonates are able to release βLPH and βEP during the first hours of life. Both these molecules may contribute to help the newborn in the transition from a close dependence on the mother, to an autonomous existence.

ISSN:0031-3998    

出版商:OVID    

年代:1982

数据来源: OVID

摘要:

SummaryThe uptake of 0.5 mM glycyl-L-proline (Gly-Pro), a substrate which has affinity for the dipeptide specific carrier system and is not hydrolyzed in the brush border, was studiedin vitroin jejunum and ileum of rabbits from the 25th day of gestational age into adulthood. For comparison, uptake of 0.5 mM glycine was studied too. Results show that influx of Gly-Pro is present from the earliest age studied and show a steep prenatal increase and peaks at birth, with values, in the newborn jejunum, of 45.2 ± 3.3 μmoles/ghr (mean ± S.E.). Thereafter, the uptake slowly declines toward the adult level of 3.8 ± 0.5 μmoles/ghr. A similar pattern was present in the ileum. On the contrary, free glycine uptake shows no statistically significant change during the whole period studied.The characteristics of the Gly-Pro influx process have been studied in the period of its peak activity (1-to 6-day-old rabbits) in both jejunum and ileum. The process is not inhibited by a 40-fold excess of glycine, proline, phenylalanine, leucine, lysine, glutamic acid, while it is strongly inhibited by a 10-fold excess of the dipeptides leucyl-leucine, alanyl-proline, glycyl-leucine and lysylleucine. A large excess of Gly-Pro has no inhibitory effect on the uptake of free glycine. The kinetic constants for Gly-Pro uptake are: Vmax = 126.7 ± 26.4 μmoles/ghr and Kt = 0.98 ± 0.26 mM in the jejunum and Vmax = 59.6 ± 9.2 and Kt = 0.70 ± 0.10 in the ileum. The removal of Na from the incubation and preincubation medium approximately halves the Vmax in both segments, leaving unchanged the affinity constants.These results indicate that a very efficient dipeptide influx process occurs in the newborn rabbit. This process displays many characteristics in common with that described in the adult: it is not shared by amino acids free in the lumen; has a broad specificity for dipeptides and shows the same pattern of Na dependence. However, its maximal velocity is in the newborn much higher than in the adult.Therefore, (1) the developmental patterns of the transport systems for Gly-Pro and for free glycine are different; this provides ontogenetic evidence for the distinction between dipeptide and free amino acid carrier systems; and (2) dipeptide uptake plays a predominant role in the physiology of the protein absorptive-digestive processes of the youngster.

ISSN:0031-3998    

出版商:OVID    

年代:1982

数据来源: OVID

摘要:

SummaryPancreatic juice was collected from rabbits treated with reserpine and from untreated controls. The volume of pancreatic juice secreted, flow rate and the bicarbonate output were all significantly reduced in the treated animals during both spontaneous flow and during secretin-stimulated flow. On the other hand, the total protein concentration, the amylase activity and the calcium concentration of the pancreatic juice were all significantly elevated in the treated animals. The elevation in the total protein concentration appeared to be due to both increased amounts of protein and decreased amounts of water. Of particular interest was that secretin stimulation caused the same % increase in the flow rate and output of pancreatic juice in both control and reserpine treated rabbits. The method by which fluid is secreted by the treated animal, therefore, appeared to be depressed at all tunes and under all conditions. Decreased volumes of pancreatic juice, a decreased bicarbonate output and increased concentrations of protein and calcium are found in this model and are consistent with clinical findings present in the pancreatic secretions obtained from individuals with cystic fibrosis. Therefore, the similarities between secretions of the reserpine treated rabbit and those observed in the cystic fibrosis patient support its use as an experimental model for investigating the abnormal pancreatic secretions in this disease.

ISSN:0031-3998    

出版商:OVID    

年代:1982

数据来源: OVID

摘要:

SummaryUmbilical cord length varies considerably and the factors controlling cord length are unknown. Experiments in rat fetuses indicate that (1) restriction of fetal movements by oligohydramnios leads to short cord. The umbilical cords were significantly shorter in proportion to the duration or time of onset of the oligohydramnios. The mean cord length represented 65% of littermate control values when persistent oligohydramnios was induced on day 15, 71% for day 16 and 78% for day 17 (term day 21). (2) Suppression of fetal movements by curarization from day 18 on leads to short cords, irrespective of amniotic fluid volume. The paralyzed fetuses with polyhydramnios had a mean cord length representing 85% of sham operated controls, and those with oligohydramnios and paralysis had a similar mean cord length, 86% of controls. (3) Extra-uterine pregnancies with the fetuses free in the maternal abdominal cavity, yet attached to their umbilical cords, led to cords measuring 147% of littermate controls. (4) In contrast, when the extra-uterine fetuses were fixed to the uterine horn, close to the placental implantation site, with little or no stretch applied to the cord, the mean cord length was 90% of littermate controls.These results indicate that tensile forces on the cord secondary to fetal movements are important determinants of cord length.

ISSN:0031-3998    

出版商:OVID    

年代:1982

数据来源: OVID

摘要:

SummaryThe composition of human milk from mothers delivering prematurely (PT) and at term (T) was studied over the first weeks of lactation. Complete 24 h milk expressions were obtained by electric pump at weekly or biweekly intervals through 44 wk conceptual age (120 samples from 20 PT mothers and 28 samples from 7 T mothers). PT milk was found to contain significantly higher concentrations than T milk of the following nutrients: total nitrogen, protein nitrogen, sodium, chloride, magnesium and iron. No differences were found between T and PT milk for nonprotein nitrogen, volume, solids, total calories, lactose, fat, fatty acids, potassium or calcium. The nutrients supplied to a 33 wk preterm infant fed 200 ml/kg/day of “average” PT milk were in excess of theoretic intrauterine requirements for all substrates except calcium and phosphorus. PT human milk is theoretically more suitable for the premature infant than either mature or term human milk, but may be deficient in specific nutrients for the very low birth weight baby.

ISSN:0031-3998    

出版商:OVID    

年代:1982

数据来源: OVID

摘要:

SummaryMineralocorticoid therapy was discontinued in 14 subjects, ages 7–17 years, with salt-losing congenital adrenal hyperplasia. The level of plasma renin activity (PRA) was determined in relation to the cumulative loss of sodium (intake-urinary output) over 4–12 days. Although the magnitude and rate of response varied, PRA increased in all subjects. There was a significant positive correlation between cumulative sodium loss and PRA (r= 0.585,P< 0.001,n= 76), and a significant negative correlation between serum sodium concentration and PRA (r= - 0.736,P< 0.001,n= 76). Significant sodium loss and elevation of PRA were seen prior to the development of hyponatremia. Thus, elevated PRA appeared to be a more sensitive indicator of sodium loss than serum sodium concentration.Fifteen infants, ages 1–33 months with salt-losing congenital adrenal hyperplasia, who were treated with subcutaneous pellets of 11-deoxycorticosterone acetate (DOCA), were also studied. PRA decreased following implantation of the DOCA pellets over 1–6 months. In most instances there was a subsequent increase in PRA, beginning at 1–8 months post implantation. There was a significant negative correlation between serum sodium and PRA (r= −0.669,P< 0.001,n= 78) in these infants. However, there were four instances in which elevated PRA was associated with normal serum sodium.Sodium balance studies were also performed on 14 of these infants during 29 admissions. All balance studies were performed at approximately 3 or 6 months after DOCA pellet implantation. On a diet containing 2 mEq Na/kg body weight per day, sodium balance was positive and there was no significant change in sodium excretion over the 3 days of observation. When a 1 mEq Na/kg/day diet was given, sodium balance was neutral on day 3 of the study, and fractional urinary sodium excretion (FeNa) decreased from 0.49 ± 0.33, S.D. on day 1 to 0.23 ± .09% on day 3 (P< 0.001,n= 19). This change was statistically significant. Net sodium balance on either diet was independent of PRA. Elevated PRA was not necessarily associated with adverse symptomatology.Thus in infants treated with DOCA pellets, elevated PRA was associated with indices of sodium depletion and decreased availability of DOCA. The dietary sodium requirement for infants treated with DOCA appeared to be 1–2 mEq/kg body weight/day.

ISSN:0031-3998    

出版商:OVID    

年代:1982

数据来源: OVID

摘要:

SummaryIn contrast to morphologic maturity, the newborn rat pancreas is unresponsive to carbachol. At 24 h, carbachol-stimulated secretion of exportable proteins markedly increases. Responsiveness to the calcium ionophore, A23187, is present at term. At age 24 h, pancreas from fasted newborn rats is also unresponsive to carbachol. When cholecystokinin octapeptide or hydrocortisone was administered to fasted newborn rats secretory function developed normally. Thus, responsiveness of newborn rat pancreas to secretagogues matures rapidly and can be induced by hormones.

ISSN:0031-3998    

出版商:OVID    

年代:1982

数据来源: OVID

摘要:

SummaryBiotin responsive multiple carboxylase deficiency was suspected in a third trimester conceptus on the basis of enzymatic confirmation in fibroblasts cultured from an earlier sibling who suffered a demise in the immediate neonatal period. Maternal urinary organic acid profile was normal throughout the final 4 wk of pregnancy. Oral administration of biotin, 10 mg/day to the mother resulted in a 100-fold increase in urinary biotin excretion within 7 days. Urinary biotin excretion over the subsequent 2 wk decreased steadily, suggesting either decreased maternal absorption or increased fetal sequestration.After the birth of nonidentical twins, cord blood and urinary organic acid profiles of the infants were normal. However, cord blood biotin concentration was 4 to 7-fold that of normal newborns. Subsequent enzymatic and genetic complementation studies utilizing cultured skin fibroblasts from the infants demonstrated one of them to be affected by the multiple carboxylase defect, although he was clinically and biochemically normal throughout the neonatal period.Thus, prenatal therapy of this inborn enzymatic defect can be safely and effectively accomplished by administration of pharmacologic biotin doses in the last month of pregnancy.

ISSN:0031-3998    

出版商:OVID    

年代:1982

数据来源: OVID