摘要:

We have conducted a cross-sectional analysis of the genetic and environmental contributions to the variance of anthropometric measurements in children during early adolescence. Univariate path analysis was used to estimate the relative contributions of genes, individual environment, and family environment to measures of childhood obesity in 259 11-y-old Caucasian twin pairs. Triceps, subscapular, and suprailiac skinfold thicknesses, as well as waist circumferences, ht, and wt were measured in a standardized protocol. In this sample, a parsimonious model that included only additive genetic effects and environmental factors unique to the individual provided an adequate explanation for the variation in ht, wt, quetelet index, and subscapular and triceps skinfolds. In this largely preadolescent population, different magnitudes of genetic effects were seen in males and females for waist circumference, biiliac diameter, and suprailiac skinfold.

ISSN:0031-3998    

出版商:OVID    

年代:1990

数据来源: OVID

摘要:

We evaluated the growth records of 15 boys and 14 girls who developed end-stage renal failure before or during puberty and who were regularly followed from the onset to the end of their pubertal growth spurt. Height data were smoothed by using the kernel estimation method. Mean values for age, height, and height velocity at defined points of the pubertal growth period were compared with those of normal children entering puberty both at an average and late age. The start of the pubertal growth spurt was delayed by 2.5 y in both sexes. Its duration and intensity were significantly reduced. Mean pubertal height gain was 17.3 cm in boys and 13.9 cm in girls, i.e. 58 and 48% of that observed in the late maturing control group. Mean height at the onset of the pubertal spurt in the patients was the same as that in the late maturing healthy girls and 1.0 SD below that of corresponding boys. During the pubertal growth spurt, mean height declined to—2.9 SD in boys and - 2 .3 SD in girls. Although skeletal maturation was increasingly retarded, we did not observe accelerated growth velocity during late puberty. Our data indicate that most patients reaching end-stage renal failure before or during puberty irreversibly lose growth potential during this period. Renal transplantation did not consistently improve pubertal growth.

ISSN:0031-3998    

出版商:OVID    

年代:1990

数据来源: OVID

摘要:

Overnight growth hormone (GH) concentrations obtained by frequent venous sampling of 20 healthy, short prepubertal boys were evaluated using the objective pulse detection algorithm, CLUSTER. The resulting pulsatile characteristics were compared with those of 11 healthy prepubertal boys of normal stature and with those of nine prepubertal children with documented GH deficiency. Although no significant differences of pulsatile GH release were found between the normal and short subjects, a subset of the short prepubertal boys with significantly delayed skeletal ages had subnormal sum of GH pulse areas and sum of GH pulse amplitudes. The finding of a significant correlation in all subjects between growth velocity and the sum of GH pulse amplitudes is important, as the results are compatible with the hypothesis that alterations of amplitude-modulated GH release underlie the pathophysiology of suboptimal growth in some short prepubertal children.

ISSN:0031-3998    

出版商:OVID    

年代:1990

数据来源: OVID

摘要:

To determine whether differential response to growth hormone-releasing hormone (GHRH) could cause the developmental changes seen in growth hormone (GH) secretion, we administered 10 µg/kg GHRH (1-44 NH2) to a group of four unanesthetized, fasted, rhesus monkeys via acutely placed venous catheters at 1, 7, 14, and 28 d postnatal age. Serum GH was assayed by hGH RIA in sera collected at -60, -30, 0, 15, 30, 45, 60, and 90 min relative to the GHRH bolus. Serum cortisol was measured by ELISA in the 0-, 30-, and 60-min samples. Differences between age groups were analyzed by repeated measures analysis of variance and pairedttests. Mean basal GH levels were higher at 1 d (9.4 ± 1.2 µg/L, mean ± SEM) than at 7 (5.5 ± 0.4), 14 (5.6 ± 0.5), and 28 d (5.3 ± 0.5) of age. There were no other significant differences in mean basal δGH values between the age groups. Mean post-GHRH GH concentrations decreased significantly with each age after 1 d (22.6 ± 1.6): 7 d (16.4 ± 1.3); 14 d (11.3 ± 1.0); and 28 d (7.9 ± 0.9). Similarly, mean δ GH values decreased with each increase in age from 1 d (15.0 ± 1.9): 7 d (10.9 ± 1.6); 14 d (5.9 ± 1.1); and 28 d (2.7 ± 0.8). Serum cortisol was not correlated with serum GH at any age. Our study demonstrates decreasing basal GH concentration and GH responses to GHRH with advancing age from 1 to 28 d in the rhesus monkey. The spontaneous decline in GH concentration observed during the first few days of life may reflect a decrease in pituitary gland response to GHRH stimulation.

ISSN:0031-3998    

出版商:OVID    

年代:1990

数据来源: OVID

摘要:

Neutrophil functions and glucose metabolism are known to be impaired in glycogen storage disease (GSD) Ib patients. The uptake of nonmetabolizing glucose analogues into polymorphonuclear leukocytes (PMN) of GSD Ib patients was studied. 2-Deoxyglucose (2-DOG) and 3-O-methylglucose are transported across the cell membrane by facilitated diffusion mediated by the glucose transporter. Because 2-DOG is phosphorylated within the cell, its uptake rate reflects hexose transport as long as phosphorylation is not rate-limiting. These conditions prevail only at low 2-DOG concentrations. Transport of 5 µM DOG into GSD Ib patient PMN was found to be similar to controls (4.3 ± 0.5 and 4.65 ± 1.77 pmol/min x106, respectively). In contrast, 2-DOG uptake at high concentrations (2 mM) decreased by 70% in patient PMN compared with control cells (0.17 ± 0.06 and 0.51 ± 0.11 nmol/ min x 106, for patients and controls, respectively). Transport of 3-O-methylglucose (a glucose analogue that does not undergo intracellular phosphorylation) was not different in patient PMN compared with controls (1.86 ± 0.53 and 2.19 ± 0.30 nmol/min x 106, respectively). Hexose monophosphate shunt activity in PMN of GSD Ib patients at a glucose concentration of 2 mM was 43% of control values, whereas at 10 µM it was similar to controls. Taken together, these results suggest that the defect in glucose uptake and metabolism found in GSD Ib patient PMN is due to an impairment in hexose phosphorylation rather than in a reduction in the transmembrane glucose transport activity.

ISSN:0031-3998    

出版商:OVID    

年代:1990

数据来源: OVID

摘要:

Studies were performed to examine the effect of dopamine on the functions of neonatal polymorphonuclear leukocytes (PMN). Cord blood PMN were treated with dopamine and assayed for their superoxide anion production by the ferricytochrome C reduction method and for their myeloperoxidase-hypochlorous system ability by the luminol-dependent chemiluminescence using a synthetic chemotactic factor, N-formyl-methionyl-leucylphenylalanine, as a stimulus. Dopamine inhibited N-formyl- methionyl-leucyl-phenylalanine-induced O2-production by neonatal PMN: when PMN were treated with 10-5M and 10-4M dopamine, the percentage inhibition values were 51 and 71%, respectively. Dopamine also inhibited the luminol-dependent chemiluminescence. PMN mobility and bactericidal ability were not affected by dopamine. Therapeutic dopamine plasma levels (873.5 ± 174.0 ng/ mL, n=13, mean ± SEM) observed in sick infants corresponded with the in vitro dopamine concentrations to inhibit the respiratory burst. Dopamine may be one of the drugs useful for reducing the oxygen-induced tissue damage associated with PMN in neonatal intensive care patients.

ISSN:0031-3998    

出版商:OVID    

年代:1990

数据来源: OVID

摘要:

Reactive oxygen metabolites have been implicated in the pathogenesis of mucosal injury induced by ischemia-reperfusion in adult animals, with recent interest centering on the capacity of polymorphonuclear neutrophilderived oxidants to mediate this injury. A role for oxidants has also been postulated in the etiology of neonatal necrotizing enterocolitis. Based on evidence that the intrinsic capacity of the neonatal piglet intestine to detoxify hydrogen peroxide (H2O2) is minimal relative to that of older piglets, we characterized the changes in mucosal permeability induced by luminal perfusion with H2O2and hypochlorous acid at concentrations that can be produced physiologically by activated neutrophils (0.05 mmol/L, 0.1 mmol/L, and 0.5 mmol/L), in the distal ileum of 1-d- and 1-mo-old piglets. Mucosal permeability was quantitated by measurement of blood-to-lumen clearance of 51-labeled chromium EDTA. Luminal perfusion with either H2O2(0.05 mmol/L and 0.1 mmol/L) or hypochlorous acid (0.1 mmol/L and 0.5 mmol/L) significantly increased mucosal permeability in newborn piglets but did not affect mucosal permeability in 1-mo-old animals. Perfusion with 0.5 mmol/L H2O2significantly increased mucosal permeability over control values in both age groups, but injury in the newborn intestine was significantly greater than that observed in 1-mo-old animals. Thus, as predicted by the reduced intrinsic capacity of the mucosa of neonatal piglets to detoxify H2O2, the ileum of newborn piglets is more vulnerable to oxidant-induced mucosal injury than is the ileum of older animals.

ISSN:0031-3998    

出版商:OVID    

年代:1990

数据来源: OVID

摘要:

We studied the effect of early weaning from maternal breast milk to artificial diets on rat jejunal absorption of an exogenous 40-kD glycoprotein, horseradish peroxidase (HRP). Rat pups, fed maternal milk (MM) from birth, received one of three diets for the last 4 d before weaning (d 17-21): MM, protein hydrolysate formula (PH), or soy formula (S). Some rats were pretreated on d 14 with intraperitoneal hydrocortisone (5 mg/rat). In MM-fed rat pups, jejunal HRP absorption was markedly higher on d 17 than on d 21. [Geometric means (95% confidence interval) were: d 17, 626.4 (461.3, 850.6) versus d 21, 90.6 (48.2, 170.5) IU HRP/mL x cm x min, p<0.01.] By contrast, 21-d-old PH- and S-fed pups maintained elevated absorption of the tracer [PH, 292.3 (177.5,480.6), p <0.05 versus MM pups, S, 340.8 (164.4, 704.8), p<0.01 versus MM pups]. wt-matched control studies indicate that the difference in HRP absorption was not due to the smaller body wt of formula-fed pups. The increased absorption in formula-fed animals was suppressed by hydrocortisone. In S-fed pups, the increased macromolecular absorption appeared, in part, to be the result of diffusion across altered villus absorptive cells. In PH-fed pups, there was no evidence of damage and HRP absorption appeared to occur by vesicle-mediated transport. Delay in the normal maturation of small intestinal “closure” appears to be associated with early weaning to artificial diets. This may lead to increased nonspecific macromolecular permeability that could result in immune-mediated sensitization and food intolerance.

ISSN:0031-3998    

出版商:OVID    

年代:1990

数据来源: OVID

摘要:

A family comprising mother, father, and five children is described. Four of the children were found to excrete massive amounts of D(+)-glyceric acid in their urine. This was verified by gas chromatography-mass spectrometry and the configuration determined by capillary gas chromatography of O-acetylated menthyl esters. The excretion ranged from 10.8 to 19.9 mmol/24 h. The remaining child and the parents showed no evidence of this unusual metabolite. The virtual absence of clinical manifestations in this family was particularly interesting. Only two of the children showed any clinical abnormality and this was limited to mild microcephaly and speech delay; the other two children found to excrete large amounts of D(+)- glycerate were healthy and developmentally normal at 7 y and 9 y of age. There was a marked increase in the excretion rate of D(+)-glycerate in response to both oral fructose and serine loading. These results are consistent with a deficiency of D(+)-glycerate kinase and indicate the potentially benign nature of this disorder.

ISSN:0031-3998    

出版商:OVID    

年代:1990

数据来源: OVID

摘要:

Two species of lipoproteins containing apoAI (A-ILp), lipoprotein containing apoA-I and apoA-II (LpA-I/A-II), and lipoprotein containing apoA-I but no apoA-II were isolated from 12 girls with insulin-dependent diabetes mellitus (IDDM) and from 19 healthy controls using affinity chromatography. When characterizing the lipid and apolipoprotein compositions, we noted compositional changes. In A-ILp, the levels of lipid, except for triglyceride, and the level of apoC-IH were significantly higher in IDDM. In LpA-I/A-II, the levels of lipids, except for triglyceride, the levels of apoC-IH, and the ratio of apoA-I to apoA-II were significantly higher in IDDM. In lipoprotein containing apoA-I but no apoA-II, the levels of all lipids and apolipoproteins in IDDM were similar to those in the controls. The percent phospholipid in A-ILp and LpA-I/A-II was significantly higher in IDDM. All of these changes of A-ILp are similar to those associated with the reduced risk in the nondiabetic population. However, apolipoprotein changes of LpA-I/A-II may possibly be related to the accelerated atherosclerotic processes noted in patients with IDDM.

ISSN:0031-3998    

出版商:OVID    

年代:1990

数据来源: OVID