摘要:

SummaryAlthough it is known that calcitonin decreases bone resorption, lowers serum calcium and phosphate, and influences the urinary excretion of these ions, its effect upon skeletal maturation in growing children has not been elucidated. Conceivably, the higher serum calcitonin levels that have been reported in children may promote bone formation and growth.To study immunoreactive urine calcitonin (iCT) in normal children, we used the radioimmunoassay (RIA) which we had developed previously to measure the hormone in normal adults and to screen persons at risk for medullary thyroid carcinoma (MTC). The measurement of urine iCT by RIA is particularly useful for children at risk for this thyroid malignancy because it obviates the need for venipunctures. Two antisera, one having region specificity for the midportion of CT (Ab-IIIb) and the other having carboxyl terminal recognition (Ab-IV), were utilized for the assay.For the carboxylterminal antiserum (Ab-IV), boys of ages 7 to 12 years (mean urine iCT, (ng/mg ± S.D.), 0.29 ± 0.18) had urine iCT levels significantly higher than girls the same age (0.13 ± 0.05) and higher than both adult males (0.16 ± 0.07) and adult females (0.084 ± 0.034). Boys ages 13 to 15 years (0.12 ± 0.03) had urine iCT concentrations which were not different from adult males. Girls of ages 7 to 12 years (0.13 ± 0.05) had iCT levels significantly lower than boys of the same age (0.29 ± 0.18), but significantly higher than adult females (0.084 ± 0.034). Girls ages 13 to 15 (0.11 ± 0.05) had urine iCT levels not significantly different from boys of the same age (0.12 ± 0.03).For the midportion antiserum (Ab-IIIb), children ages 7 to 15 (0.58 ± 0.384) had urine iCT concentrations greater than adults (0.26 ± 0.10), but there were not significant differences in levels between boys and girls of the same age.Gel filtration studies revealed greater amounts of higher molecular weight fractions (pU-2, ∼14,600 daltons; pU-3, ∼11,000) of urine calcitonin than were found in the urine of most normal adults and all patients with MTC.Previously, we have established criteria for diagnosing MTC in adults using Ab-IV in the urine calcitonin RIA. These adult criteria can be applied to females of all ages and to males ≥12 years of age, but levels for boys <12 years require the adjusted criteria reported in this publication. In the present study, when using Ab-IV (the carboxyl terminal antiserum used in the previous MTC study), we have found higher urine iCT levels in children than among adults. The mean level in the various age groups decreased with age. Using the data obtained from this study, we can be more certain of our determination that a child between the ages of 6 and 15 is either normal or has MTC.

ISSN:0031-3998    

出版商:OVID    

年代:1981

数据来源: OVID

摘要:

SummaryFetal-like erythropoiesis frequently accompanies marrow stress conditions such as Diamond-Blackfan syndrome and aplastic anemia. In contrast, patients with transient erythroblastopenia of childhood have erythrocytes which lack fetal characteristics at the time of diagnosis. This report describes nine children with transient erythroblastopenia of childhood in whom transient, fetal-like erythropoiesis was observed during the period of recovery. These patients initially presented with anemia, reticulocytopenia, erythrocytes of normal size for age, low levels of fetal hemoglobin, and i-antigen. During the recovery period, however, erythrocytes manifested one or more fetal characteristics. These included an increased fetal hemoglobin (in three of five patients), the presence of i-antigen (in four of six patients), and macrocytosis (in seven of nine patients). These fetal characteristics persisted more than 2 wk after the reticulocyte count returned to normal. Within one year from diagnosis, red blood cells contained no fetal characteristics.

ISSN:0031-3998    

出版商:OVID    

年代:1981

数据来源: OVID

摘要:

SummaryNet nitrogen retention (NNR) and rates of whole-body protein turnover (Q), synthesis, and breakdown (B) were measured in 24 intravenously fed premature infants, birthweight <1600 g, at the end of the first week of life. Four regimes were used: Amigen-glucose ± Intralipid; Vamin-glucose ± Intralipid. Mean protein intake was 2.7 g/kg/day. Mean energy intakes were 68 to 98 kcal/kg/day.Vamin was a better protein source (P< 0.01), evidenced by a higher NNR; 72 ± 2%,cf. 56 ± 4% at high-energy intakes. The high-energy intake also improved (P< 0.01) protein retention (NNR); 64cf. 50%. Infants receiving 2.9 g of Vamin (394 mg N)/kg/day and 85 kcal/kg/day of nonprotein intake retained nitrogen at intrauterine rates (282 ± 7 mg/kg/day).Diet had no effect on Q, synthesis, or B. However, the protein source had a significant effect (P< 0.01) on the fraction of N-flux coming from protein breakdown (B/Q); 71.1% for Vamin,cf. 77.1% for Amigen. Similarly, energy intake had a significant effect (P< 0.01) on the fraction N-flux utilized for protein synthesis (S/Q); 91.3% high energycf. 87.0% low energy. These results suggest that an increased energy intake improved N-retention by enhancing amino acid reutilization for protein synthesis, whereas a higher quality protein improved N-retention by limiting protein breakdown.

ISSN:0031-3998    

出版商:OVID    

年代:1981

数据来源: OVID

摘要:

SummaryTo study the normal development of blood coagulation factor activities in a growing fetus while avoiding the effects of labor and delivery, a chronic fetal lamb model was developed in which serial blood samples from 10 fetuses were studied during the third trimester of pregnancy and 24 hr after birth. Under operating room conditions with sterile technique, a polyethylene catheter to which heparin had been bound to both internal and external surfaces was inserted into the femoral artery of the fetus. The catheter was brought out through a skin pouch to the side of the ewe and enclosed in a zip lock bag. Blood samples were withdrawn from the catheter three times each week for measurement of coagulation factor activities. Levels of coagulation factor activities at birth in noncatheterized animals were not different from those found in catheterized animals except for factor IX activity which was 12% higher in the catheterized animals (0.02 <P< 0.05). The patterns of development for each of the coagulation factors were similar in all 10 animals studied. Fibrinogen, prothrombin, and factor VII show a decrease in activity early in the last trimester of pregnancy whereas other factors V, VIII, IX, X, XI, XII, and XIII show a gradual increase in activity throughout the last trimester of pregnancy. Both factors VIII and IX show a significant increase in activity (23% factor VIII and 12% factor IX) associated with the process of delivery. The levels of coagulation factor activities at birth in the lamb relative to adult sheep normals are similar to those found in humans with the exception of factor XIII. Factor XIII is at normal levels in the newborn lamb and is reported to be at levels approximately 50% of the adult level in human infants.

ISSN:0031-3998    

出版商:OVID    

年代:1981

数据来源: OVID

摘要:

SummaryImmunoreactive cathodal elastase, elastinolytic activity, and activity on the low-molecular elastase substrate succinyl-trialanine were assayed in duodenal juice from 89 fasting children with different malabsorption problems. Cathodal elastase immunoactivity (mean value, 0.06 g/liter) averaged 1% of the total protein content in duodenal juice and 1/16 of the succinyl-trialanine-splitting activity. A strong influence of age was found for immunoactivity and elastimolytic activity, indicating continuing development of the cathodal elastase during the first 24 months of life.In 81 children with normal pancreatic function, significantly lower levels for all parameters including total protein were found for 14 with coeliac disease than for 34 children with unclassified gastrointestinal disorders and 33 with cow's milk protein intolerance. In eight children with pancreatic insufficiency, seven lacked detectable immunoactive cathodal elastase; low levels of succinyl-trialanine-splitting activity were found in six, and remnants of elastinolytic activity in three.

ISSN:0031-3998    

出版商:OVID    

年代:1981

数据来源: OVID

摘要:

SummaryThe time spent in REM, quiet, and indeterminate sleep was computed in 13 aborted SIDS infants and compared to that spent in the same sleep states in 19 normal infants. Aborted sudden infant death syndrome (SIDS) infants were studied within a week of their aborted SIDS episode and subsequently at monthly intervals through the age of 4 months. Normal infants were studied at 1, 2, 3, and 4 months of age. Sleep staging was performed by two independent observers using electroencephalogram, electrooculogram, electromyogram and behavioral criteria. Although there was an increase in the percentage of time spent in quiet sleep with age in both normal and aborted SIDS infants, the significantly greater regression coefficients in normal infants (6.3versus2.9;P< 0.01) indicate that there are differences in the two groups and suggest a maturational abnormality or delay in sleep state distribution in aborted SIDS infants.

ISSN:0031-3998    

出版商:OVID    

年代:1981

数据来源: OVID

摘要:

SummaryPrevious studies have suggested that fetal hyperinsulinemia which occurs in offspring of diabetic mothers is responsible for diminished surfactant production and respiratory distress syndrome. Recognition of specific insulin effects on fetal lung tissue prompted us to characterize insulin receptors on plasma membranes of fetal rabbit lung tissue and to investigate the effects of maternal diabetes on such receptors. Six pairs of pregnant New Zealand rabbits were studied. One of each pair received alloxan (60 mg/kg) intravenously on day 14 of pregnancy, whereas the controls received saline. Animals were sacrificed on day 28 of gestation, and for each experiment, crude plasma membranes were prepared from maternal and pooled fetal lung tissue for125I-insulin binding studies. Plasma glucose values were elevated for both maternal diabetic (246 ± 81versus98.5 ± 7.1 mg/dl;P< 0.001) and fetal diabetic offspring (160 ± 69versus55 ± 12 mg/dl;P< 0.02) in comparison to controls. Fetal diabetic offspring had plasma insulin values significantly higher than control fetuses (84.8 ± 25versus23.2 ± 3.7 μU/ml), (mean ± S.D.);P< 0.05). Insulin was undetectable in diabetic mothers.Lung membranes from fetuses of diabetic animals bound significantly more insulin than did those of control fetuses. Scatchard analysis yielded curvilinear plots of bound fractionsversustotal amount of insulin bound suggesting the presence of more than one class of receptors or negative cooperativity. Assuming two classes of receptors, one of high affinity and low capacity and another of low affinity and high capacity, we found that fetal membranes had a five-fold increase in binding capacity of high-affinity receptors as compared to adult membranes. In spite of marked hyperinsulinemia in the offspring of the diabetic animal, the fetal lung, far from experiencing a down-regulation of insulin receptor binding, showed increased insulin binding. This finding is consistent with observations made previously on circulating monocytes of infants of diabetic mothers.

ISSN:0031-3998    

出版商:OVID    

年代:1981

数据来源: OVID

摘要:

SummaryCysteamine is the most effective agent known for the reduction of the elevated cystine content of cells from patients with cystinosis. A defect in endogenous cysteamine generation could account for many of the metabolic features of this disorder. To test this hypothesis, we have developed improved methods for measuring pantetheinase (cysteamine-generating) activity and intracellular cysteamine levels and used these methods to measure such parameters in cystinotic and normal leukocytes and cultured skin fibroblasts. Pantetheinase activity as defined in the text was similar in extracts of cystinotic and normal cells [leucocytes, normal, 78 ± 15 (S.E.), cystinotic, 56 ± 6.4; fibroblasts, normal, 9.4 ± 1.5; cystinotic, 7.7 ± 1.7]. Cysteamine levels were normal in leukocytes from cystinotics receiving no cysteamine or doses of oral cysteamine too low to reduce leukocyte cystine content. The results indicate that the cause of cystinosis is unlikely to be related to a failure to generate or sustain normal intracellular cysteamine levels.

ISSN:0031-3998    

出版商:OVID    

年代:1981

数据来源: OVID

摘要:

SummaryThis study was designed to determine the critical difference between rat milk and rat chow with respect to their effects on jejunal sucrase activity during the fourth postnatal wk. Rats were weaned onto special diets on postnatal day 17, and jejunal sucrase was assayed on day 28. A pelleted diet containing lactose as sole carbohydrate did not cause depression of sucrase activity. Sucrase values (μmoles/hr/mg protein) were 10.49 ± 0.81 (n= 15) for the lactose chow and 6.65 ± 0.29 (n= 16) for the sucrose chow. This indicates that the nature of the dietary carbohydrate does not account for the sucrase differences of weaned and nonweaned animals. Likewise, the physical consistency of the diet is unimportant because sucrase values were just as high on a liquid diet (10.91 ± 0.77 μmoles/hr/mg protein;n= 8) as on the solid diets. However, when the relative proportions of carbohydrate and fat in the diet were varied, there were significant effects on sucrase activity; values on a low carbohydrate diet (4.30 ± 0.33 μmoles/hr/mg protein;n= 8) being less than one-half those on a high carbohydrate diet (10.91 ± 0.77 μmoles/hr/mg protein;n= 8).

ISSN:0031-3998    

出版商:OVID    

年代:1981

数据来源: OVID

摘要:

SummaryUsing anin vivoclosed-loop technique in rat jejunum, we have confirmed previousin vitrostudies that cystic fibrosis (CF) serum inhibits water, sodium, and glucose absorption and transmural potential difference. CF heterozygote serum or sera from children with diarrhoeal disorders not associated with exocrine pancreatic insufficiency had no effect on transport. Sera from patients with Shwachman's syndrome and exocrine pancreatic insufficiency had identical effects to CF serum. These results challenge the specificity of the CF “factor.”

ISSN:0031-3998    

出版商:OVID    

年代:1981

数据来源: OVID