摘要:

PhenylethanolamineN-methyl transferase (PNMT), the terminal enzyme in epinephrine biosynthesis, was identified in fetal and newborn ovine lung. The ovine lung PNMT demonstrated the appropriate substrate specificity and affinity (Km, 9 x 10-6M). Although some homology between adrenal and lung PNMT was observed on polyacrylamide gel electrophoresis, the lung PNMT differed in its migration on ion exchange chromatography and was not inhibited by pharmacologic inhibitors active against the adrenal enzyme. Activity increased from a mean of 132 pmole/(mg protein · h) x 10-3at 0 days gestation to 326 pmole/mg protein · h) x 10-3in newborn animals between 1–4 days of age (r= 0.571,P< 0.05). The levels ofN-methylating activity in extraadrenal tissues were relatively low; lesser but significantN-methylating activities were demonstrated in brown adipose tissue and myometrial tissues. Adrenal gland activity was 1000-fold greater than lung activity expressed on a per mg protein basis and 250-fold greater expressed per mg wet weight.

ISSN:0031-3998    

出版商:OVID    

年代:1983

数据来源: OVID

摘要:

Newborn rats were exposed to air or hyperoxic conditions for the first 6 days of life. Resulting effects on the pulmonary vascular bed were determined by analysis of barium angiograms, scanning electron microscopy of methylmethacrylate corrosion casts and whole lung, morphometric estimations of pulmonary arteries/area and capillary number/area, and arterial blood gas measurements. Similar studies were also performed on the lungs of animals allowed to recover in air for 1 and 2 wk. Although the general pattern of the pulmonary arterial bed by barium angiograms appeared similar, diminished branching or underfilling of the distal arterial segments was more frequently encountered in hyperoxic-exposed animals. Morphometric examination and corrosion casts revealed differences in vascular pattern and density between hyperoxia and air-exposed animals. The number of capillaries/mm2of lung tissue was less in hyperoxic-exposed pups than controls after 6 days of exposure to hyperoxia but markedly increased to slightly above control levels by 2 wk of air recovery. The number of 20–50 μm size vessels/mm2followed a similar pattern of change. Corrosion casts of lungs exposed to 6 days of hyperoxia revealed less microvascular density compared to air controls, but after 1 wk recovery in air, hyperoxic-exposed animals had a more extensive network of microvessels. Maximum Pao2attained by animals in the various groups closely resembled the patterns of change in microvessel density. These findings support the thesis that a major alteration of lung vascular growth and development occurs subsequent to exposure of the newborn to hyperoxia.

ISSN:0031-3998    

出版商:OVID    

年代:1983

数据来源: OVID

摘要:

The distribution and metabolism of infused exogenous [125I] inactive plasma big renin, molecular weight 56,000, was studied in five newborn puppies. The animals were sacrificed and the organs removed and studied by chromatography, along with periodic blood samples taken during the 120-min study, for evidence of conversion of high-molecular-weight renin to low-molecular-weight renin. The decay curve suggested an initial rapid distribution (alpha) phase of 10 ± 1.5 min followed by a slower elimination (beta) phase of 40 ± 4.6 min. [125I]-Big renin was taken up by the red blood cell and released slowly. The liver, kidneys, and lungs had the highest % of [125I]-big renin at the termination of the study. There was no chromatographic evidence of a change in molecular weight of the [125I]-big renin. These data show that big renin has a two-compartment disappearance curve and that there is no evidence of conversion of high-molecular-weight renin to low-molecular-weight renin systemically or in the tissues of the newborn canine puppy.

ISSN:0031-3998    

出版商:OVID    

年代:1983

数据来源: OVID

摘要:

Disaccharide feedings to post-weaning rats alters their jejunal barrier to macromolecular absorption. Penetration of horseradish peroxidase (HRP) across the jejunum was enhanced after shortterm high concentration gavage (30 g · kg-1· day-1) of lactose that produces weight loss, osmotic diarrhea, and jejunal mucosal damage. HRP absorption was also increased by longer term feedings of lower levels of disaccharide that did not produce body weight alterations, diarrhea, or cell damage. Rats without diarrhea and gavaged with 7.5 g · kg-1· day-1of either lactose or maltose showed an increase in lumen to blood HRP absorption after 21 days of feedings. Also, lactose or maltose in the solid food diet at 30 g· kg-1· day-1for 21 days did not lead to diarrhea but produced an increase in jejunal lumen to blood HRP absorption. Rats having no diarrhea and receiving 15 g · kg-1day-1of lactose or maltose in the drinking water for 21 days, showed an increase in jejunal HRP absorption. When rats were fed either lactose or maltose for 21 days glucose absorption became totally dependent upon the sugar concentration in the perfusion medium. The kinetics of this glucose absorption are compatible with a decrease in the “unstirred” layer. Disaccharide-induced HRP absorption may be mediated by transport from endocytotic vesicles across the jejunal epithelium.

ISSN:0031-3998    

出版商:OVID    

年代:1983

数据来源: OVID

摘要:

Kidney tissue from human fetuses of gestational ages ranging 12–26 wk were studied by histochemical and biochemical methods. Clear staining for carbonic anhydrase activity was found in both proximal and distal parts of some nephrons already at gestational age of 12–15 wk. The staining pattern in the inner cortex of the fetuses of 24 and 26 wk did not differ markedly from that in adult renal cortex, except for the absence of capillary staining; proximal and distal convoluted tubules as well as initial collecting tubules exhibited distinct enzyme activity. In the outer cortex, where the nephronogenic zone is located, newly formed nephrons with no or little staining were found in all kidneys. Loops of Henle were absent or sparse in the medulla of the fetuses of 12–17 wk. Fully developed loops of Henle were relatively few also in the fetuses of 24 and 26 wk; the thick ascending limb and part of the thin limb were stained in such loops. The collecting ducts in all kidneys contained a varying number of intensely stained cells interspersed among unstained or weakly stained ones.The catalytic activity and the immunoassayable amount of carbonic anhydrase were determined in homogenates of renal cortex from three fetuses (19,21, and 26 wk). The kidney from the fetus of 26 wk showed the highest values with an enzyme activity and an immunoassayable amount of HCA-C corresponding to 204 enzyme units and 0.14 mg enzyme per g wet weight of tissue, respectively. These values are similar to those of adult renal cortex and indicate that all of antigenically determined HCA-C is also catalytically active in the kidney at this gestational age.As judged from their content of carbonic anhydrase many nephrons might be fully able to reabsorb bicarbonate and secrete hydrogen ions in human fetuses of 24–26 wk. Other nephrons are much less developed at this stage, however. This nephronic heterogeneity might at least partly explain the reduced capacity for urinary acidification which has been reported for premature newborn infants.

ISSN:0031-3998    

出版商:OVID    

年代:1983

数据来源: OVID

摘要:

Cytogenetic studies have been carried out on 17 children with acute nonlymphocytic leukaemia (ANLL). Of the 16 patients analysed at diagnosis, 11 had acquired clonal chromosome abnormalities. Four out of seven cases with acute myeloid leukaemia (M2) had 8;21 translocations, two of which were variants. Comparisons with other data on ANLL confirmed the association between the 8;21 translocation and the younger age groups. There are indications that the Netherlands may be a high incidence area for this translocation. Differences in the type of chromosome anomalies between childhood and adult ANLL were evident suggesting that different aetiologic factors may be involved.

ISSN:0031-3998    

出版商:OVID    

年代:1983

数据来源: OVID

摘要:

A direct immunofluorescent technique with fluorescein-labeled antigens was used to examine the jejunal mucosa for specific antibody production in 23 children aged 2–25 months referred for diagnostic biopsy. Plasma cells containing antibodies to β-lactoglobulin (βLG) or bovine serum albumin (BSA) were present in 11 of 16 biopsies from patients with cow's milk protein intolerance (CMPI) but only one of eight controls, all on a diet containing cow's milk. Antibody-containing cells (ACC) constituted approximately 0.5–5% of the total (IgA + IgM) plasma cell population. Their presence did not correlate with either histologic abnormality or IgA plasma cell count. Double immunofluorescence with rhodamine-labeled antigens and fluorescein-labeled class-specific anti-human immunoglobulin sera showed the ACC to be approximately 70% IgA cells and 30% IgE cells.

ISSN:0031-3998    

出版商:OVID    

年代:1983

数据来源: OVID

摘要:

Familial erythrophagocytic lymphohistiocytosis (FEL) is an autosomal recessive disease of unknown pathogenesis. Because of evidence of increased circulating and hepatic lipids in FEL, we performed a comprehensive analysis of the hepatic lipids of a patient with this disease. In contrast to normal qualitative characteristics and to normal or only mildly elevated concentrations of total lipids, neutral lipids, phospholipids, and neutral glycosphin-golipids, this study reports a significant elevation of acidic glyco-sphingolipids, gangliosides (387versus147 nmole lipid-bound sialic acid/g wet weight, patientversuscontrol). This quantitative abnormality was unusual in that it included disproportionately increased concentrations of most of the minor hepatic ganglioside species rather than either a marked increase in one single or a generalized nonspecific increase in all gangliosides, which is characteristic of known disorders exhibiting hepatic ganglioside storage. Activities of the hepatic lysosomal glycosylhydrolases which are important in ganglioside metabolism were therefore assessed by using artificial substrates. Of the enzymes tested, β-galactosidase activity alone was remarkable, being moderately reduced (33% of that of the normal liver); no biochemical explanation for the reduction was found. The findings suggest FEL may be associated with a unique quantitative and qualitative abnormality in hepatic gangliosides, the cause of which remains to be elucidated.

ISSN:0031-3998    

出版商:OVID    

年代:1983

数据来源: OVID

ISSN:0031-3998    

出版商:OVID    

年代:1983

数据来源: OVID

ISSN:0031-3998    

出版商:OVID    

年代:1983

数据来源: OVID