摘要:

Respiratory alkalosis (hypocapnia) is used to treat persistent pulmonary hypertension in newborns. With the exception of the brain, there are no data on the effects of hypocapnia on organ blood flow in the neonate. Therefore, we examined the effects of 2 h of hypocapnia on blood pressure, oxygen consumption, cardiac output and organ blood flows in puppies.In six animals (group I), reducing the Paco2to 21.8 ± 1.5 mm Hg (pH 7.62 ± 0.04) caused an immediate and sustained reduction in cerebral blood flow (40%) and in myocardial blood flow (25%). There were no significant changes in arterial blood pressure, total body oxygen consumption, cardiac output, right and left ventricular rate-pressure product, or blood flow to the gut, liver, muscle, and kidneys.In four control animals (group II) (Paco239.8 ± 3.0, pH 7.38 ± 0.04), there were no changes in any of the measured variables (arterial blood pressure, total body oxygen consumption, cardiac output, or blood flow to any organ, including brain and heart) during 2 h of normocarbic ventilation.We did not determine whether the reductions in cerebral and myocardial blood flows were detrimental. We suspect that they were not because the animals did not develop metabolic acidosis and they had normal cardiac outputs, and ventricular rate-pressure products throughout the study.

ISSN:0031-3998    

出版商:OVID    

年代:1984

数据来源: OVID

摘要:

The activities of CDP reductase and thymidine kinase in 106to 5 x 106phytohemagglutinin (PHA)-stimulated lymphocytes isolated from 2 to 5 ml of peripheral blood of individual subjects were measured. The activities of CDP reductase (pmol/h/107cells) and thymidine kinase (nmol/h/107cells) were high in infants, 698 ± 307 and 64.2 ± 20.2, constant in subjects of 1–40 years old, 401 ± 181 and 38.1 ± 15.3, and low in persons of more than 80 years old, 121 ± 113 and 22.3 ± 17.8, respectively. The ratio of thymidine kinase to CDP reductase activity increased with age, indicating that dependency on the salvage pathway of DNA synthesis in lymphocytes increased with age. The activities of CDP reductase and thymidine kinase were reduced in patients with the hyperimmunoglobulin E syndrome, congenital cytomegalovirus infection, anhidrotic ectodermal dysplasia with hyperimmunoglobulin A, Bloom's syndrome, immunodeficiency with hyperimmunoglobulinemia, and Down's syndrome. The clinical symptoms of these diseases seem to be due to impaired DNA synthesis of PHA-stimulated lymphocytes, but the degrees of reduction of enzyme activities were generally greater than that of thymidine incorporation in these patients.

ISSN:0031-3998    

出版商:OVID    

年代:1984

数据来源: OVID

摘要:

Bilirubin-IXα photooxidation products were detected by high performance liquid chromatography in the urine of neonates undergoing phototherapy for hyperbilirubinemia. Thein vivophotoproducts were identified by chromatographic comparison with authentic synthetic standards using two complementary methods. Bilirubin photooxidation products were not detected in urine from jaundiced infants not receiving phototherapy. The specific photoproducts identified in the urine include propentdyopents, hematinic acid imide and its hydrolysis product (3-carboxy-2-methyl-2-hexenedioic acid), and the hydrolysis product (2-vinyl-3-methyl-maleic acid) of methylvinylmaleimide. Their total urinary concentrations were low (0.2–0.9 mg/dl) during phototherapy. These observations show that photooxidation of bilirubin clearly does occur during phototherapy. They are consistent with the view that, although photooxidation is not the major photochemical event associated with phototherapy, it can and clearly does occur concurrently with photoisomerization.

ISSN:0031-3998    

出版商:OVID    

年代:1984

数据来源: OVID

摘要:

We investigated the importance of arginine-vasopressin (AVP) for blood pressure control in young and adult rats. Most of the studies were performed on Brattleboro rats with complete diabetes insipidus (DI). In some protocols, Sprague-Dawley rats (SD) were also used. The rats were age 20–24 days (young) or 50–80 days (adult). Adult DI rats have a significantly higher mean arterial pressure (MAP) than adult SD rats. The studies were performed during normovolemia and hypovolemia. Hypovolemia was created by the rapid withdrawal of blood, 0.5–1.5% of body weight. Following bleeding 0.5% of the body weight, young DI rats had a significantly larger decrease in MAP than adult DI and young and adult SD rats. Continuous infusion of AVP (2000 pg±100 g-1min-1) blunted the hemorrhagic hypotension in the DI rats.In all groups of rats studied, AVP had little effect on the MAP during normovolemia. The effect of AVP (given in a bolus dose of 20 or 2000 pg±100 g-1) on the MAP was in DI rats significantly related to the MAP immediately prior to the AVP administration. No effect on MAP was observed when the initial MAP was 105–112 mm in the young DI rats and 148–157 mm in the adult DI rats. The effect of AVP (20 pg±100 g-1) appeared to be submaximal to maximal. In anaesthetized SD rats, the basal AVP production was higher in the young than in the adult animals. Following bleeding, serum AVP increased in both young and adult rats but the increase was significant only in the adult rats.

ISSN:0031-3998    

出版商:OVID    

年代:1984

数据来源: OVID

摘要:

A study was carried out in order to investigate whether the abnormalin vitroturnover of fatty acids in the phospholipids of the red blood cell membranes of cystic fibrosis patients is intrinsic to the membrane, or whether it is induced by extrinsic serum factors. Red blood cells of cystic fibrosis patients and healthy subjects were labeledin vitrowith [14C]linoleic acid, bound to albumin. The labeled cells were reincubated in autologous and homologous serum. The radioactivity present in the serum lipids and in the major phospholipid fractions of the red cell membranes was measured.Conclusions of this study are: 1) not all of the cystic fibrosis patients examined individually show an abnormalin vitroturnover of the red cell fatty acids, although they all presented abnormal fatty acid patterns for the red blood cell phospholipids, ±

ISSN:0031-3998    

出版商:OVID    

年代:1984

数据来源: OVID

摘要:

By the combination of energy and macronutrient balances, continuous open circuit computerized indirect calorimetry, and anthropometry, we have compared small for gestational age (SGA) and appropriate for gestational age (AGA) very low birthweight infants with respect to metabolizable energy intake (mean ± SE: 125.9 ± 2.5versus130.4 ± 3.5 kcal/kg±day), energy expenditure (67.4 ± 1.3versus62.6 ± 0.9 kcal/kg±day), storage of energy and macronutrients and growth. Fourteen studies in six SGA infants (gestational age, 33.1 ± 0.3 weeks; birthweight, 1120 ± 30 g) and 22 studies in 13 AGA infants (gestational age, 29.3 ± 0.4 weeks; birthweight, 1155 ± 40 g) were performed. The SGA infants had a lower absorption of fat (68.7 ± 3.2versus79.7 ± 1.7%) and protein (69.1 ± 3.2versus83.4 ± 1.5%) and hence increased (P> 0.001) energy loss in excreta (29.9 ± 2.8versus18.2 ± 1.5 kcal/kg±day). The significant hypermetabolism of SGA infants by 4.8 kcal/kg±day was associated with an increased fat oxidation. Despite lower energy storage, SGA infants were gaining weight (19.4 ± 0.9 g/kg±day), length (1.25 ± 0.14 cm/week), and head circumference (1.16 ± 0.9 cm/week) at higher rates than the AGA group. The energy storage per g weight gain was lower (P> 0.001) in the SGA group (3.0 ± 0.14versus4.26 ± 0.26 kcal) reflecting higher water, lower fat (22.2 ± 1.8versus33.8 ± 2.5%;P> 0.001) and lower protein (7.7 ± 0.5versus12.5 ± 0.8%;P> 0.001) contents of weight gain in the SGA group.

ISSN:0031-3998    

出版商:OVID    

年代:1984

数据来源: OVID

摘要:

A stable isotope dilution assay for galactitol, in amniotic fluid has been developed using selected ion monitoring chemical ionization gas chromatography-mass spectrometry of the hexaacetate derivative. [1,1-2H2]Galactitol was synthesized for use as the internal standard. Galactitol is a component of normal amniotic fluid with a mean concentration of 0.70 ± 0.18 μmol/liter (n= 5). The amniotic fluid of a fetus with galactosemia had a concentration of 7.96 μmol/liter. Mannitol, sorbitol, and inositol were also found to be normal constituents of amniotic fluid. This stable isotope dilution assay is a rapid accurate method for measurement of galactitol in amniotic fluid for prenatal diagnosis of galactosemia.

ISSN:0031-3998    

出版商:OVID    

年代:1984

数据来源: OVID

摘要:

α-Methyl-D-glucoside (AMG) uptake was examined in isolated renal cortical tubules from newborn, 3-month-old, and adult dogs. All three age groups demonstrated active sugar transport. The initial rate of AMG uptake was similar in the 3-month-old and adult tubules which was twice that of the newborn. At steadystate, the adult and newborn tubules had achieved a similar intracellular AMG concentration which was 45% greater than that of the 3-month-old. Determination of the flux constants of these uptake patterns revealed that there was an age-dependent increase in both the net flux and the fractional influx rate constant. However, the 3-month-old had the highest fractional efflux rate constant and the newborn the lowest value with the adult in between. Kinetic analysis of AMG uptake showed a single saturable transport system for each age group. The newborn and adult had similar Kmvalues but the 3-month-old had a value that was 60% higher. The 3-month-old tubules had the highest Vmaxand the newborn tubules the lowest with the adult value in between. AMG uptake by tubules from each age group demonstrated a similar pattern of inhibition in a low sodium buffer and by glucose and phlorizin. This indicated that, aside from kinetic changes with maturation, the saturable transport system for AMG is similar in each age group.

ISSN:0031-3998    

出版商:OVID    

年代:1984

数据来源: OVID

摘要:

We report the evaluation ofin vitroimmunoregulation in a 12-year-old untreated boy with severe combined immunodeficiency (SCID). Severely hypogammaglobulinemic, the patient was incapable of a specific antibody response to either natural substances or administered antigens. Ficoll-Hypaque-isolated peripheral blood mononuclear cells (MNL) from the patient failed to respond to pokeweed mitogen (PWM) with the normal increment in immunoglobulin-secreting cells, as measured by a reverse hemolytic plaque assay. Since the patient was lymphopenic, his MNL were relatively enriched for monocytes (range = 51–81%). Removal of phagocytic cells or the addition of unrelated irradiated helper T lymphocytes resulted in enhanced, but still suboptimal response to PWM, suggesting some intrinsic defect in B lymphocyte function. Co-culture of patient MNL with normal MNL resulted in marked suppression (12% of predicted) of PWM-induced Ig-secreting cells. Suppressor activity was unaffected by prior irradiation of patient MNL, but was substantially reversed (99% of predicted) by removal of his phagocytic cells, whereas the combination of the two procedures further reversed suppression (184% of predicted). The patient's MNL consistently demonstrated subnormal percentages of T3+ and T4+ cells and subnormal to low normal percentages of T8+ cells. These data suggest both an intrinsic defect in B lymphocyte function, and a relative excess of monocytes which could further inhibit Ig secretion by B lymphocytes. Natural killer (NK) cell function was characterized by normal target cell binding by NK cells but severely depressed NK cell cytotoxicity.

ISSN:0031-3998    

出版商:OVID    

年代:1984

数据来源: OVID

摘要:

Rhesus monkey infants were injected subcutaneously at birth with 12 to 100 μmol of tin-protoporphyrin IX, a competitive inhibitor of microsomal heme oxygenase. The elevated unconjugated serum bilirubin levels of the neonates receiving this metalloporphyrin rapidly declined to near adult levels by 24–30 h. Control neonates which received an injection of saline exhibited normal physiologic hyperbilirubinemias of from 3–6 mg/dl by 12–24 h as expected. These studies establish the effectiveness of tin-protoporphyrin IX in depressing bilirubin production and preventing physiologic hyperbilirubinemia in simian neonates. Two of six animals receiving the metalloporphyrin exhibited signs of toxicity.

ISSN:0031-3998    

出版商:OVID    

年代:1984

数据来源: OVID