摘要:

During the early months of life, gains in length and weight are more rapid by formula-fed than by breast-fed infants and we and others have speculated that the greater gains of the formula-fed infants are the result of greater food intake. If overfeeding during early infancy resulted in establishment of habits of overeating, or if, for any other reason, diet-induced fatness in infancy persisted into childhood, we might be able to demonstrate differences in fatness in childhood related to mode of feeding (breast or bottle) during infancy. We therefore examined at age 8 years 469 children born in 1966-1971 who had been studied intensely in our unit from 8 to 112 days of age. At age 8 years there were no differences in indices of fatness related to mode of feeding during infancy.Serum concentrations of cholesterol at age 8 years were also of interest because of reports from animal studies that differences in feeding during early life may be responsible for subsequent differences in cholesterol homeostasis. Cholesterol concentrations at age 8 years did not demonstrate significant differences related to mode of feeding during infancy. It is possible, however, that age 8 years is too early for an effect to be demonstrated.

ISSN:0031-3998    

出版商:OVID    

年代:1984

数据来源: OVID

摘要:

Human lymphocyte antigen (HLA)-DR-typing was performed in 117 insulin-dependent diabetics with age at onset between 0.5 and 17 years (mean ± SD, 9.0 ± 3.9); 115 of 117 patients were DR3- and/or DR4-posirive. DR4 was very common, seen alone or in combination with other DR types in 82.9% of the patients. Only two children were DR2-positive, but they also were DR4-positive. A comparison between DR3 and DR4 patients snowed that DR4 patients manifested a seasonal variation of onset (most common onset during spring and autumn), had more severe signs and symptoms of the disease at onset, and were less likely to have a partial remission than patients with DR3. The results support the hypothesis that insulindependent diabetes mellitus is a genetically heterogeneous disease.

ISSN:0031-3998    

出版商:OVID    

年代:1984

数据来源: OVID

摘要:

Cholesterol ester and triglyceride metabolism was examined in intact fibroblast monolayers from normal individuals and patients with Wolman's disease and cholesterol ester storage disease. Cholesterol esters were introduced into ceils by incubation in medium containing [3H]cholesteryl linoleate (CL) bound to human low density lipoprotein. Triglycerides were introduced by incubation with glycerol tri[l-14C]oleate (triolein) bound to human very low-density lipoprotein. Both types of mutant cell lines accumulated the unhydrolyzed substrates to a greater extent than did normal cells with the greatest accumulation observed in Wolman's disease cells. Wolman's disease cells hydrolyzed CL at 10-22% and triolein at 11-19% the rate of normal cells; cholesterol ester storage disease cells hydrolyzed these substrates at 28-49 and 30-47% the normal rate, respectively. In contrast, assays of acid lipase activity in cell lysates revealed less than 1% of control activity in both disorders. The data suggest that the mutant acid lipase present in Wolman's disease and cholesterol ester storage disease is more active in the intact cell than assays of cell lysates would indicate. In addition, the differences observed between the two disorders provide a biochemical explanation for the different phenotypes associated with the two disorders.

ISSN:0031-3998    

出版商:OVID    

年代:1984

数据来源: OVID

摘要:

Antepartum administration of L-carnitine to pregnant rats results in an increase of both total phospholipid (80 ± 11 mg/g dry weight (dw); mean ± SD) and dipalmitoylphosphatidylcholine (DPPC) content (7.7 ± 2.1 mg/g dw) in fetal lungs as compared to controls (72 ± 10 and 7.0 ± 2.5 mg/g dw, respectively). On the other hand, no effect of L-carnitine could be demonstrated on the DPPC portion in the total phosphatidylcholine (PC) or on the portion of palmitic acid in the PC fatty acids.Betamethasone elevated the DPPC content in fetal lungs (8.1 ± 2.0 versus 7.0 ± 2.5 mg/g dw in the controls), while total phospholipid content remained unaffected (71 ± 19 versus 72 ± 10 mg/g dw). The portion of DPPC in the PC species increased significantly (p<0.01) from 27.6 ± 4.5 in the fetal lungs of the control group to 34.2 ± 3.3 in the lungs of the betamethasone-treated group, while the palmitic acid portion in the PC fatty acids was nearly unchanged (45.9 ± 3.2 versus 43.9 ± 2.6 in the controls). Further, after betamethasone treatment, a significant diminution (p<0.01) of the monoenic PC 32 species (palmitoyl- palmitoleyl PC and palmitoleyl-palmitoyl-PC) and the PC 34 species (consisting primarily of palmitoyl-oleoyl- PC) could be demonstrated both in absolute and relative terms. This is in agreement with a significant reduction of the portions of palmitoleic (p<0.01) and oleic (p<0.05) acids in the total PC fatty acids. The findings suggest two different mechanisms of DPPC elevation in fetal rat lungs for L-carnitine and betamethasone.

ISSN:0031-3998    

出版商:OVID    

年代:1984

数据来源: OVID

摘要:

Twoin vitrointestinal models were used to investigate postnatal maturational changes of the gut barrier functions. Microvillus membrane (MVM) preparations were studied for surface binding, and everted gut sacs were studied for mucous coat binding, breakdown and uptake of radioiodinated bovine serum albumin (BSA), and β-lactoglobulin (β-LG). Surface binding of these proteins to MVM was weak and nonspecific. There was more binding of both proteins to immature MVM (BSA: newborns, 2.74 ± 0.52%, adults, 1.08 ± 0.17%, p<0.001; β LG: newborns, 6.30 ± 0.54%; adults, 2.05 ± 0.07, p<0.001). In contrast to MVM binding characteristics, mu-cous coat binding of the cow's milk proteins to immature gut sacs was significantly less (BSA: preweanlings, 0.94 ± 0.30 µg125-I-protein Eq/mg mucosal protein; adults, 3.06 ± 0.74, p<0.001; β-LG: preweanlings, 5.61 ± 1.48; adults, 9.83 ± 1.33, p<0.001). Protein binding and uptake were correlated in the immature animals (r=0.76, p<0.001 for BSA and r=0.85, p<0.001 for β-LG). More β-LG was bound and taken up than BSA in the preweanlings (p<0.001). Trichloroacetic acid precipitation studies showed that, even in the immature rats, β-LG was much more readily broken down by mucosa-associated enzymes than BSA. Immature animals showed less protein breakdown than adult controls. Decreased protein breakdown and mucous coat binding as well as increased MVM binding may account for the increased uptake of intact food antigens in the newborn. Differences between increased MVM binding and decreased mucous coat binding of cow's milk proteins are attributed to protective elements such as the mucus layer which is present in the gut sac model but lacking in MVM.

ISSN:0031-3998    

出版商:OVID    

年代:1984

数据来源: OVID

摘要:

Frozen storage is often used by milk banks to preserve expressed human milk for later use. Optimal storage and handling conditions which ensure minimum alteration of lipid composition have not been well defined. Therefore we investigated the effect of rapid freeze−thawing and storage conditions (−20 and −70° C) on the free fatty acid (FFA) levels and on the activities of lipoprotein lipase (LPL) and bile salt−stimulated lipase (BSSL) in human milk. Since during mechanical expression leakage of serum components into milk may occur, we also investigated the effect of the presence of serum on human milk LPL during storage. Lipase activity levels were unaffected by rapid freeze−thawing (x3) followed by storage for 1 month at −20 or −70° C. LPL activity (nmol FFA released/ml milk/min) was 414 ± 128, 451 ± 37, and 351 ± 20 and BSSL activity (μmol FFA/ml milk/min) was 5.7 ± 0.7, 5.5 ± 0.8, and 5.7 ± 0.2 in fresh, freeze−thawed, and stored milk, respectively. FFA levels (% of total lipid) were 3.01 ± 1.05 and 10.3 ± 1.6 in fresh−frozen milk stored at −7 0 and −20° C for 5 months, and 3.78 ± 1.08 and 13.60 ± 1.25 in specimens of freeze−thawed (x3) before storage at −70 or −20° C. Addition of serum had no effect on milk LPL at either temperature. We conclude that LPL and BSSL remain fully active during frozen storage of human milk and that milk fat is hydrolyzed at −20° C but not at −70° C. We suggest that banked human milk be stored routinely at −70° C.

ISSN:0031-3998    

出版商:OVID    

年代:1984

数据来源: OVID

摘要:

Cardiovascular responses to the calcium antagonists verapamil and nifedipine were evaluated in a piglet model of hypoxic pulmonary hypertension. All animals were mechanically ventilated and paralyzed. Cardiac output (CO), pulmonary artery (Ppa) and aortic blood pressure (AoP), pulmonary wedge pressure, right atrial pressure (Pra), and arterial blood gases were measured prior to and after pulmonary hypertension was induced by hypoxia and after administration of calcium-blocking agents. Results were compared to a control group of piglets subjected to a similar period of hypoxia. Verapamil infusion (0.15 mg/kg) resulted in a rapid decrease in Ppa, AoP and pulmonary vascular resistance (p<0.05) which returned to baseline values by 15 min. Nifedipine (100 µg/ kg) resulted in a decrease in Ppa at 1 min (p<0.05) which remained significantly lower than controls throughout the study period. AoP declined precipitously during the same time period (p<0.01). No significant change in Ppa was noted when nifedipine was administered at a dose of 10 µg/kg. For the most part, these drugs have a transient vasodilatory action on pulmonary as well as systemic circulation in this animal model; however, they might in higher doses be associated with significant systemic hypotension. For this reason, the use of these drugs in the treatment of hypoxic pulmonary hypertension in the neonate should be approached with caution.

ISSN:0031-3998    

出版商:OVID    

年代:1984

数据来源: OVID

摘要:

Although obstructive nephropathy is a frequent cause of renal insufficiency in infancy, factors influencing adaptation to chronic partial ureteral obstruction (CPUO) are poorly understood. Guinea pigs were subjected to unilateral CPUO within the first 2 days of life (Group I) and microsphere studies were performed at 23 ± 3 days of age. To also investigate the role of functional renal mass on growth and hemodynamics, contralateral nephrectomy was performed in Group II at the time of ureteral constriction. Compared to sham-operated controls (ureteral diameter=1 mm) CPUO caused impaired somatic growth in both groups. Resulting hydroureteronephrosis was variable and most severe (ureteral diameter>3 mm) in azotemic animals of Group II, which demonstrated reduced compensatory renal hypertrophy and poorest somatic growth.Mean arterial blood pressure was not affected by CPUO or uninephrectomy. Renal blood flow (RBF) was higher in Group II than Group I, and did not fall significantly with severity of CPUO in Group II, in which number of perfused glomeruli was similar to controls. In contrast, renal vascular resistance (RVR) increased by 172% in animals of Group I with severe CPUO, and was associated with 34% fewer perfused glomeruli than in the hypertrophied contralateral kidney. With increasing severity of CPUO, RBF tended to be distributed to outer cortical regions in the obstructed kidney of Group I, while the shift in RBF distribution was from outer to inner cortex in the remaining kidney of Group II. Filtration fraction fell as a result of CPUO in both groups, such that reduction in the glomerular filtration rate was due in large part to factors other than RBF. In conclusion, CPUO in the neonatal guinea pig causes marked alterations of glomerular perfusion. Contralateral nephrectomy prevents the rise in RVR due to CPUO, possibly by preserving perfusion to all nephrons and shifting blood flow to more mature deeper cortical glomeruli.

ISSN:0031-3998    

出版商:OVID    

年代:1984

数据来源: OVID

摘要:

Neonatal guinea pigs with chronic partial ureteral obstruction (CPUO) and contralateral nephrectomy develop hydroureteronephrosis and reduced glomerular nitration rate (GFR) without significant reduction of renal blood flow. To investigate the role of pressure gradients in determination of GFR, micropuncture studies were performed in animals 23 ± 3 days of age subjected to left ureteral constriction and right nephrectomy within the first 2 days of life and compared to uninephrectomized controls. Resulting ureteral dilatation was variable, with kidney weight and ureteral diameter being proportional to the rise in ureteral pressure (Pv120 s). Superficial single nephron GFR (SNGFR) was inversely correlated with Pv.Glomerular capillary pressure and afferent arteriolar colloid oncotic pressure were not affected by CPUO while peritubular capillary, proximal and distal intratubular hydrostatic pressure increased as a function of Pu. As a result, afferent effective filtration pressure (EFPA) was reduced in severe (10.0 ± 1.1 mm Hg) compared to mild CPUO (13.4 ± 0.5 mm Hg), but was not different from controls (11.3 ± 0.9 mm Hg). For both control and CPUO groups, superficial SNGFR increased by 0.5 nl/min for each mm Hg increase in EFPAbut for a given EFPA, SNGFR was 6 nl/min lower in guinea pigs with CPUO. These results indicate that higher EFPA in animals with mild compared to severe CPUO contributes to maintenance of higher SNGFR. However, a 70% reduction in superficial SNGFR for guinea pigs with severe CPUO is due in large part to reduced ultrafiltration coefficient. The mechanisms whereby chronically elevated Pvin the neonate result in these complex changes of glomerular dynamics may relate to altered intrarenal production of vasoactive hormones.

ISSN:0031-3998    

出版商:OVID    

年代:1984

数据来源: OVID

摘要:

This study determines the inotropic effects of prostaglandin D2(PGD2) and prostaglandin E1(PGE1) in the isolated, arterial perfused newborn (NB) and adult (A) rabbit heart.Significant positive inotropism of PGD2was observed at all concentrations studied (1 x 10-17to 1 x 10-7M) in the two age groups; the effect in the NB was significantly greater (p<0.05) than that in the A at PGD2concentrations higher than 1 X 10-17M. Significant positive inotropism of PGE1was observed at PGE1concentrations higher than 1 x 10-8M in the NB, and only at 1 x 10-6M in the A.In the NB, the relaxation parameters [1/2ART and the ratio of +dT/dt (max) to -dT/dt (max)] decreased to 80% of control after PGE1infusion, but not after PGD2infusion. In contrast, relaxation parameters in the A were not different from control.Propranolol (1 x 10-6M) did not alter the positive inotropic action of PGD2and PGE1in the NB. These data indicate that: 1) the positive inotropic effects of PGD2and PGE1in NB are greater than that in the A, 2) PGE1and not PGD2, enhances myocardial relaxation only in the NB,3) the contractile effects of PGD2and PGE1are not mediated by β-receptors.

ISSN:0031-3998    

出版商:OVID    

年代:1984

数据来源: OVID