ISSN:0031-3998    

出版商:OVID    

年代:1986

数据来源: OVID

摘要:

The effects on the conceptus of persistently decreased maternal plasma amino acid concentrations were studied in pregnant rats by the infusion of glucagon (0.21 mg/day) to the mother from day 14 to 20 of gestation with a subcutaneous, osmotically driven minipump. Controls received diluent. The experimental animals either had normal caloric intake and weight gain, or diminished caloric intake with no weight gain. Both experimental groups exhibited a decrease in plasma total amino acid concentration of approximately 50%. Maternal plasma glucose and insulin concentrations were unaffected except for slight decreases in the low weight gain group. At cesarean section on day 20, fetal weight was unaffected in the normal weight gain group, while the low weight gain animals exhibited intrauterine growth retardation. Fetal plasma glucose and insulin concentrations were unaffected. Despite the marked decrease in maternal plasma total amino acid concentration, fetal plasma total amino acid concentration was unaffected. Individual plasma amino acid concentrations in the normal weight gain mothers and fetuses revealed a spectrum of changes. Some maternal amino acids were decreased by more than 60% (α-aminobutyric acid, asparagine, threonine, glutamine, alanine) while others were unaffected (tyrosine, tryptophan, phenylalanine, histidine). In general, amino acids that were decreased in the mother exhibited no change or a lesser decrease in fetal plasma concentration, while those that were unaffected in the mothers showed increased fetal concentrations. Fetuses from the low weight gain mothers had plasma amino acid profiles that were similar to those of the normal weight gain mothers. We speculate that the preserved fetal plasma amino acid concentrations are due to enhanced placental transport of amino acid secondary to maternal substrate decrease.

ISSN:0031-3998    

出版商:OVID    

年代:1986

数据来源: OVID

摘要:

In this study we have carried out α-globin gene mapping, hemoglobin (Hb) Bart's quantitation serum bilirubin, and red blood cell indices determination in a group of Sardinian appropriate for gestational age premature infants (from 32 to 35 wk gestation) in order to define the incidence in this population of the different α-thalassemia syndromes, their expression rate, and the correlation between the α-globin genotype and phenotype at this developmental stage. The gene frequencies of deletion (-α) and nondeletion (ααth) α-thalassemia were 0.29 and 0.04, respectively, and thus not different from those found in full-term newborns from the same population. The majority of premature newborns with a single α-globin gene deletion [(-α/αα) genotype] were hematologically silent. Those who manifested increased Hb Bart's (1.2 to 3.4%) had slightly reduced Hb levels (17.4 ± 2.6 g/dl), mean corpuscular volume (102.6 ± 6.3 fl), and mean corpuscular Hb (34.8 ± 2.0 pg) values. Those infants with the deletion of two α-globin structural genes (-α/-α) showed without exception moderate amount of Hb Bart's in the 3.5-8.1% range and an obvious decrease of Hb levels (16.1 ± 1.6 g/dl) mean corpuscular Hb (30.6 ± 3.5 pg), and mean corpuscular volume (88.5 ± 11.5 fl) values. The only infant with the deletion of 3 α-globin structural genes had 25% Hb Bart's associated with a moderate microcytic anemia at birth and developed the clinical picture of Hb H disease. Carriers of nondeletion α-thalassemia (αα/ααth) showed variable amount of Hb Bart's always associated with thalassemia-like red cell indices. Higher Hb Bart's levels were observed in those subjects carrying the initiation codon mutation of the α2 gene as compared with carriers of other nondeletion α-thalassemia defects.

ISSN:0031-3998    

出版商:OVID    

年代:1986

数据来源: OVID

摘要:

Seventy-two fetal blood samples obtained by umbilical vein puncture under ultrasound guidance for prenatal diagnosis and monitoring purposes were tested for the expression of 38 blood group antigens. The gestational age at sampling ranged from 18 to 34 wk with 76% of fetuses between 20 and 25 wk. Compared to adult red blood cells, the following antigens showed either abnormally decreased frequency, or significantly reduced expression: A, B, A1, H, Lua, Lub, Lea, Leb, P1, P, and I. Selected anti- I and anti-i cold agglutinins, active at room temperature, were used at appropriate dilution, in a rapid slide or spin test to check for possible mixture of the sample with maternal blood and were shown to detect contaminations up to 5%. The test has proved particularly helpful for immediate and in process assessment of foetal origin of the sampled blood.

ISSN:0031-3998    

出版商:OVID    

年代:1986

数据来源: OVID

摘要:

The sera from 32 patients with cystic fibrosis who were chronically colonized with mucoid strains ofPseudomonas aeruginosa(MPA) were tested for anti-MPA antibodies. Using an enzyme-linked immunosorbent assay we measured IgA, IgG, and IgM antibody titers to three MPA strains, extracts of those strains, and seaweed-derived sodium alginate, which is similar chemically to the exopolysaccharide of MPA. These titers were compared with identical tests performed on the sera of eight cystic fibrosis patients who never were colonized with MPA and 10 normal adults. The IgG titers were significantly higher in tests of sera from the colonized patients compared with the other two groups but the IgA and IgM titers were not significantly higher. In colonized patients antibody titers to the different antigens correlated with each other suggesting that the major antibody response was to common antigenic determinants. Using these titers as a data base, eight patients whose clinical status was unknown to the testers, had IgG-enzyme-linked immunosorbent assay tests of their sera and the four colonized patients with cystic fibrosis were correctly identified. Three of them had substantial titers of antibody in the bronchoalveolar lavage fluid.

ISSN:0031-3998    

出版商:OVID    

年代:1986

数据来源: OVID

摘要:

The red blood cell population of the human newborn is more heterogeneous than that of adults. To characterize this heterogeneity, red cells were separated on Stractan gradients into populations according to their density and, therefore, generally according to their age. Lipid content, phospholipid asymmetry, osmotic fragility, and deformability were measured. With increasing density, osmotic resistance and deformability decreased to a greater extent in the neonatal than the adult red cell. There was a marked loss of surface area throughout the life span of the neonatal red cell which was not accompanied by a parallel loss of membrane lipid. This apparent discrepancy could be explained at least in part by internalization of membrane lipid as a result of endocytosis, a process shown to be present in even the densest neonatal red cells.

ISSN:0031-3998    

出版商:OVID    

年代:1986

数据来源: OVID

摘要:

We examined the catecholamine response to insulin-induced hypoglycemia in 46 short children evaluated for growth hormone (GH) deficiency by both pharmacologic stimulation and integrated concentration of GH. Twelve patients had quantitatively normal GH secretion by both pharmacologic stimulation and integrated concentration of GH (GHNORM). Twenty-two patients had normal GH to pharmacologic stimulation but subnormal integrated concentration of GH (GHND). Twelve patients had GH deficiency by both tests (GHD): six had isolated GH deficiency (GHD type 1) and six had multiple hormone deficiencies (GHD type 2). There was no significant difference between the peak epinephrine, norepinephrine, and cortisol responses of GH-NORM, GHND, and GHD type 1 patients. The mean peak epinephrine response of GHD type 2 patients was significantly lower (564 ± 561 pg/ml,p<0.03) compared to the other patient groups. There was no significant difference between the peak norepinephrine levels between GHD type 2 patients and the remaining groups. There was no correlation between decrease in blood glucose and either increase in growth hormone, catecholamine, or cortisol concentrations. There was a significant correlation between log peak epinephrine and peak cortisol response (r=0.53,p<0.0002) of the 46 subjects. Neither the basal nor stimulated catecholamine levels correlated with the integrated concentration of cortisol. We conclude that 1) isolated GH deficiency is not associated with impairment of the catecholamine response to hypoglycemia; 2) impairment of the epinephrine response to hypoglycemia is only associated with multiple pituitary hormone deficiencies; 3) in children, the degree of glucose lowering is not correlated with the magnitude of peak GH, catecholamine, or cortisol responses.

ISSN:0031-3998    

出版商:OVID    

年代:1986

数据来源: OVID

摘要:

Cerebral blood flow (CBF) and cerebral metabolic rate of oxygen (CMRO2) were measured during normocarbia and during both moderate and severe hypocarbia. Eighteen newborn mongrel dogs, 1 to 7 days of age, were given pancuronium and ventilated with 70% N2O and 30% O2. The respirator was adjusted to achieve a PaCO2of 15 torr, all subsequent changes to 25 and 40 torr were made by adjusting the inspired concentration of CO2. The sequence of PaCO2levels was randomized. CBF was measured by microsphere technique and CMRO2calculated as arterial-sagittal sinus O2content difference times hemispheric blood flow. AH measurements were made after 30 min at each PaCO2. Total CBF was reduced at a PaCO2of 25 torr (P<0.001), further reduction in PaCO2to 15 torr resulted in a significant decrease in total CBF (P<0.01) compared to 25 torr CO2. All regional cerebral blood flows were reduced at a PaCO2of 25 torr (p<0.001), and most regional CBFs had further significant decreases in flow at a PaCO2of 15 torr. CMRO2was 1.28 ± 0.47 ml/ 100 g/min at a PaCO2of 40 torr and fell to 1.09 ± 0.34 (P<0.05) and to 1.04 ± 0.28 (P<0.025) ml/100 g/min at PaCO2values of 25 and 15 torr, respectively. Cardiac output was calculated to be 169 ± 71 ml/kg/min at a PaCO2of 40 torr and fell to 135 ± 27 (P<0.025) and to 127 ± 36 (P<0.005) ml/kg/min at PaCO2values of 25 and 15 torr, respectively. Regression analysis of the relationship between PaCO2and CBF for values of PaCO2between 10 and 50 torr was nonlinear (In CBF=a + b-PaCO2). A series of regression curves for regional CBF are presented with R values between 0.69 and 0.81 (P<0.001). It is concluded that hypocarbia to PaCO2values of 25 and 15 torr results in significant decreases in total as well as regional cerebral blood flows. CMRO2and cardiac output also show significant decreases at PaCO2values of both 25 and 15 torr compared to normocarbia. A nonlinear relationship is demonstrated between regional CBF and PaCO2between 10 and 50 torr.

ISSN:0031-3998    

出版商:OVID    

年代:1986

数据来源: OVID

摘要:

We have reported the longitudinal distribution of vascular resistance in the three segments (arteries, microvessels, and veins) of the pulmonary circulation of adult rabbits (J Appl Physiol 60:539-545, 1986). To determine the longitudinal distribution of vascular resistance in lungs of younger animals, we measured microvascular pressures in the subpleural microcirculation in nine isolated blood perfused lungs of 3- to 4-wk-old rabbits. We used micropipettes and the servonull pressure measuring system to directly measure pressures in 20-50 µm diameter subpleural arterioles and venules. We also measured pulmonary arterial and left atrial pressures and lung blood flow. To determine the influence of vascular tone on segmental vascular resistance, in four lungs we measured microvascular pressures both before and after paralyzing the vasculature with papaverine. We found that 51% of the total pressure drop in the pulmonary circulation was in arteries, 24.5% in microvessels, and 24.5% in veins. Vascular tone contributed minimally to baseline arterial resistance. The greater arterial and venous resistance in lungs of 3- to 4- wk-old rabbits as compared to that in adult rabbits is probably due to differences in vessel geometry.

ISSN:0031-3998    

出版商:OVID    

年代:1986

数据来源: OVID

摘要:

Phenylketonuria is a human model for the study of the effects of phenylalanine on brain function. We found previously a correlation between high blood phenylalanine, prolonged performance times on neuropsychological tests of higher integrative function, and decreased urinary dopamine in 10 patients. In this protocol we examine changes in triplicate of plasma dihydroxyphenylalanine (L-DOPA) and the mean power frequency of the electroencephalogram in eight additional older patients with phenylketonuria using longer intervals in a blinded, cross-over design. Mean power frequency was obtained by Fourier transform of the power spectrum from traditional eight channel electroencephalograms. PlasmaL-DOPA was quantitated by radioenzymatic methods. In all patients statistically significant decreases were found in the mean power frequency of the electroencephalogram and in plasmaL-DOPA when plasmaL-phenylalanine increased. These findings were reversible and correlated in the reverse direction when plasmaL-phenylalanine was reduced. Thus changes in the mean power frequency of electroencephalograms and circulatingL-DOPA offer sensitive parameters of human brain functionin vivo. These findings indicate reversible effects of elevated plasma phenylalanine on electrical function of the brain which may be mediated in part through inhibition of catecholamine synthesis.

ISSN:0031-3998    

出版商:OVID    

年代:1986

数据来源: OVID