ISSN:0031-3998    

出版商:OVID    

年代:1985

数据来源: OVID

摘要:

Regional and total gastrointestinal (GI) blood flow, O2delivery, O2extraction, and O2consumption were measured before and after acute blood volume expansion in 2-day-old piglets. Blood flow was measured with radionuclide-labeled microspheres. Sixty minutes after a rapid transfusion of age- and hematocrit-matched piglet donor blood,5lCr-measured blood volume increased 19% while an increase in hematocrit suggested plasma transudation to the extravascular space had occurred in response to blood volume loading. Following transfusion, total GI blood flow and O2delivery did not change, although O2extraction decreased by 31 ± 4%. O2consumption by the GI tract decreased from 2.0 ± 0.19 ml O2·min-1·100 g-1to 1.46 ± 0.24 ml O2·min-1· 100 g-11 h after transfusion. Feeding was then accomplished via orogastric tube to determine if animals stressed by blood volume loading would increase GI O2consumption in response to feeding. The postprandial increase in GI O2consumption was similar to that previously reported in newborn piglets. Therefore, in the fasting state, acute blood volume loading disrupts GI O2transport at the capillary level and decreases GI O2consumption. However, animals subjected to blood volume loading appear capable of increasing GI O2consumption after feeding.

ISSN:0031-3998    

出版商:OVID    

年代:1985

数据来源: OVID

摘要:

The sequential changes in several glycolytic enzymes, glucose-6-phosphate dehydrogenase, glycolytic intermediates, and adenosine triphosphate, as well as intracellular pH and plasma inorganic phosphorus were followed simultaneously in eight lambs from birth to 2 months of age. The activities of all glycolytic enzymes and glucose- 6-phosphate dehydrogenase were elevated at birth. The 2,3-diphosphoglycerate concentration increased markedly postnatally and was associated with a simultaneous increase in the concentrations of red cell glucose-6-phosphate and total triose phosphate and a decrease in intracellular pH. Inorganic phosphorus also increased and correlated with the 2,3-diphosphoglycerate concentration in the first 10 days of postnatal life. The content of red cell 3-phosphoglycerate, 2-phosphoglycerate, phosphoenolpyruvate, and ATP increased slightly. These results suggested increased glycolytic flux through the diphosphoglycerate mutase reaction which resulted in net synthesis of 2,3- diphosphoglycerate. The red cell total triose phosphate peaked and fell initially, followed by glucose-6-phosphate and 2,3-diphosphoglycerate suggesting inhibition of phosphofructokinase activity and a decrease in glycolysis secondary to decreased red cell intracellular pH. After 10 days of postnatal life all glycolytic intermediates fell simultaneously, which correlated with a decrease in activity of the glycolytic enzymes.

ISSN:0031-3998    

出版商:OVID    

年代:1985

数据来源: OVID

摘要:

Daily treatment of newborn Swiss-Webster mice with triiodothyronine (T3, 500 ng/day) increased epidermal growth factor (EGF) content in whole skin (epidermis + dermis). Separation of the epidermis using 0.01 M dithiothreitol followed by processing for radioimmunoassay measurement reveals levels of EGF 2-to 3-fold higher in epidermis than in whole skin.In vitroflotation of circular skin sections from control and T3 treated neonatal mice in medium containing [I125]EGF showed increased uptake of label following 5 days of in vivo T3 treatment. Mouse skin membrane preparations exhibit saturable, specific binding of [I125]EGF. T3 treatment for 5 days in vivo significantly increased EGF binding capacity in skin membrane preparations but did not alter EGF receptor affinity (Kd 4.5 nM). Protein, RNA, and DNA concentrations were significantly increased in whole neonatal mouse skin following T3 administration. These results suggest one mechanism by which thyroid hormones increase skin EGF concentration is augmentation of skin EGF receptor binding.

ISSN:0031-3998    

出版商:OVID    

年代:1985

数据来源: OVID

摘要:

We used a nutritional deprivation model to produce intrauterine growth-retarded (IGR) rat pups (birth weight=~75% of normal). The IGR newborns evidenced a marked reduction in tolerance to >95% O2exposure: 10- day survival=10/7 (21%) versus 18/36 (50%) for control pups, and LT50=7.2 days versus 10 days for controls (p<0.01). Various lung parameters at birth and during O2exposure were examined to try to define why prenatal undernutrition should compromise the survival of IGR rats in hyperoxia. We found decreased lung glutathione peroxidase and glucose-6-phosphate dehydrogenase activity (with normal superoxide dismutase and catalase levels) in the IGRs at birth; decreased lung disaturated phosphatidylcholine content (even more markedly decreased in 1- day premature pups); and decreased lung surface area/body weight. These factors and other features of newborn IGRs reported in the literature may help to explain how prenatal undernutrition compromises postnatal tolerance to prolonged high-O2exposure.

ISSN:0031-3998    

出版商:OVID    

年代:1985

数据来源: OVID

摘要:

The possibility that pulmonary surfactant, characterized by a phosphatidylglycerol deficiency, as in early fetal life, might have inferior surface properties was evaluated. We obtained this specific surfactant from adult rabbits by withholding glucose and giving them an excess of myoinositol by mouth and intravenously. Controls were given a similar quantity of glucose. The myoinositol resulted in a drastic reduction of surfactant phosphatidylglycerol, from 7.2 to 0.3% of phospholipids, and a corresponding increase in phosphatidylinositol from 4.8 to 11.3%. In addition, the myoinositol treatment increased the myoinositol that was disaturated from 18.5 to 27.3% (p<0.05). The corresponding figures for disaturated phosphatidyl- choline were 56.0 and 60.5%, respectively (NS). The myoinositol treatment for 4 days increased the pool size of alveolar surfactant by 32% (p<0.01). The surface activity was studied with modified Wilhelmy balance and the pulsating bubble surfactometer. Surfactant containing phosphatidylinositol rather than phosphatidylglycerol was not inferior, as compared to surfactant that contained phosphatidylglycerol (minimum surface tension: 2.0 versus 2.2 mN·m-1; collapse rate at 10 nM·m-1: 1.85 versus 1.95 min-1; rate of adsorption from subphase to surface: 32 versus 35 mN·m-1·30 s-1), nor was there a difference in the ability of the two surfactants to improve lung stability of 27-day-old rabbit fetuses (air retention at 35 cm H2O: 1.8 versus 1.8 ml/30 g; air retention at 0 cm H20: 0.8 versus 0.9 ml/30 g). We conclude that phosphatidylinositol surfactant does not have inferior surface properties. Myoinositol affects not only the acidic surfactant phospholipids but also increases the pool size of surfactant by an as yet unknown mechanism.

ISSN:0031-3998    

出版商:OVID    

年代:1985

数据来源: OVID

摘要:

Lipoprotein lipase is the rate-limiting factor for hydrolyzing triglycerides to glyerol and fatty acids. Carnitine is a cofactor in the transport of long-chain fatty acids through the mitochondrial membrane for oxidation. To assess these determinants of fat utilization during total parenteral nutrition, lipoprotein and hepatic lipase activities and carnitine concentrations of nine newborn infants, operated on because of gastrointestinal anomalies during the first day of life, were measured with specific methods. Total parenteral nutrition was built up in 3 days whereafter the infants received 3 g/kg of fat at a constant rate of infusion for 24 h/day. Lipoprotein lipase activity of postheparin plasma increased from 14 to 35 µmol free fatty acids/ml/h. during parenteral nutrition whereas hepatic lipase activity remained unchanged at 40 µmol free fatty acids/ml/h. Serum free carnitine and acylcarnitine levels decreased significantly during parenteral nutrition; urinary excretion of carnitine decreased also. In addition, serum cholesterol and phospholipids increased markedly during parenteral nutrition whereas serum triglycerides, free fatty acids, and blood β-hydroxybutyrate remained unchanged. Serum apolipoprotein A-I concentrations were unaltered, apolipoprotein A-II underwent a transient increase, and apolipoprotein B increased monotonically during parenteral nutrition. The results suggest that under the present circumstances neither lipoprotein lipase activity nor carnitine resources are rate-limiting for the utilization of fat in newborn infants during total parenteral nutrition.

ISSN:0031-3998    

出版商:OVID    

年代:1985

数据来源: OVID

摘要:

Group B streptococcus is an important pathogen in man and infection due to this bacteria is responsible for significant mortality and morbidity in neonates. An animal model of neonatal infection caused by group B streptococcus that results from vertical transmission is described. Nine pregnant Sprague-Dawley rats received intraperitoneal inoculation of 109-1010 colony forming units of group B streptococcus on day 20 or 21 of gestation. Four of nine rats died following inoculation. A total of 51 pups was born to the surviving five mothers. Pups were sacrificed at 4- to 8-h intervals and cultures of blood, brain, liver, and spleen were obtained. Nineteen of 51 pups (37%) had group B streptococcus isolated from blood or tissues within the first 48 h of life. Results suggest that antepartum systemic infection in rats can result in vertical transmission of disease. This animal model can be used to further study the mechanisms of transmission of group B streptococcus and the pathogenesis and treatment of neonatal sepsis caused by this pathogen.

ISSN:0031-3998    

出版商:OVID    

年代:1985

数据来源: OVID

摘要:

To delineate the role of growth hormone (GH) in the development and function of the immune system, immunological parameters including quantitative immunoglobulins, T and B lymphocytes, phytohemagglutinin lymphoproliferative response and delayed hypersensitivity skin tests were studied in nine GH-deficient children prior to GH therapy and at 2 months and 9 to 12 months following therapy. The phytohemagglutinin response (74.1 ± 37.6, mean ± SD), and the T rosette (58.3% ± 9.4), B rosette (21.1% ± 6.1), IgG (810 ± 241 mg/dl), (IgA 140 ± 85), and IgM (176 ± 70) levels in GH-deficient children were comparable to age adjusted values in normal children. Following GH therapy the phytohemagglutinin response increased significantly at 9 to 12 months posttherapy, 123.2 ± 51.9 versus 74.1 ± 37.6, p<0.05. T and B rosettes, immunoglobulin concentrations, and hypersensitivity skin tests were not affected by GH therapy. Al-though an effect of GH was not demonstrable by these studies, a positive role of GH cannot be entirely excluded since total GH deficiency did not exist in all children.

ISSN:0031-3998    

出版商:OVID    

年代:1985

数据来源: OVID

摘要:

The unconjugated and conjugated bile acid levels in sera of 98 normal children and nine normal adults were measured by high performance liquid chromatography. The results showed that the mean total bile acid level was high, 11.0 ± 8.7 µmol/liter (1 SD) during the neonatal period (0-4 wk) and then gradually decreased with age. The ratio of the concentration of conjugated bile acids to total bile acids in serum was as high as 90% or more in infants under 1 yr of age and slowly decreased with age. The mean ratio of cholic acid to chenodeoxycholic acid was high (1.7 ± 1.1) during the neonatal period but decreased after 3 months to the adult level (0.4 ± 0.2). The mean ratio of glycine conjugated bile acids to taurine conjugated bile acids was 3.0 ± 3.1 during the neonatal period and the ratio during the 1st month of life was significantly lower than that after that period with little further change at any age. The mean ratio of the concentration of secondary bile acids to primary bile acids showed significantly lower values in infants less than 1 yr of age. The main bile acid was glycocholic acid in the neonatal period but after 1-3 months glycochenodeoxycholic acid predominated. With age, the serum bile acid pattern which was characteristic in infancy gradually approached that of adults.

ISSN:0031-3998    

出版商:OVID    

年代:1985

数据来源: OVID