摘要:

SummaryTo investigate the effect of maternal diabetes on pulmonary phospholipid metabolism, we studied fetuses of rabbit does made diabetic with alloxan. Incorporation of radiolabeled choline into total and saturated phosphatidylcholine was measuredin vitroin lung slices from 27.5 days gestation fetuses. No difference in choline incorporation was found between the diabetic and control groups even when disaturated phosphatidylcholine was measured. It was concluded that the previously described physiologic differences (i.e., decreases in lung deflation stability and surface activity of lung lavage) between fetuses of alloxan‐diabetic and control rabbits must be due to some mechanism other than impaired phosphatidylcholine biosynthesis by the choline incorporation pathway.SpeculationThe increased occurrence of respiratory distress syndrome (RDS) in infants of diabetic mothers (IDM) may be due to a deficiency of a component of surfactant other than phosphatidylcholine, an impairment of surfactant secretion, or the presence of a surfactant inhibitor.

ISSN:0031-3998    

出版商:OVID    

年代:1980

数据来源: OVID

摘要:

SummaryFour hyperglycemia very low birthweight (VLBW) infants were given a constant infusion of insulin with parenteral alimentation in order to improve glucose tolerance. After an initial 45% decrease in serum glucose, intolerance recurred within hours to days despite delivery of as much as 16 units/kg/hour of regular insulin. Resulting serum insulin levels were as high as 72,000 &mgr;U/ml. It is suggested that insulin “resistance”, instead of insulin deficiency, may be responsible for glucose intolerance in some infants.SpeculationAbnormal hepatic regulatory systems, immature enzyme systems, or abnormal insulin receptors may play a part in the glucose intolerance of the premature infant. Further studies, both in human infants and in appropriate animal models will have to be done to determine the etiology (ies) of the glucose intolerance.

ISSN:0031-3998    

出版商:OVID    

年代:1980

数据来源: OVID

摘要:

Summary&bgr;‐glucosidase activity from normal human cultured fibroblasts was not affected by the presence of up to 0.1% (w/v) (1.86 mM) purified sodium taurocholate. At concentrations greater than 0.1%, there was a gradual decrease in activity. Conversely, &bgr;‐glucosidase activity from fibroblasts of three patients with juvenile onset Gaucher's disease was preferentially inhibited by the detergent at concentrations as low as 0.025% (0.46 mM). A 40% decrease in activity was observed at 0.1%. Crude sodium taurocholate was more potent in inhibiting &bgr;‐glucosidase activity from both the normal and Gaucher fibroblasts. However, very high background fluorescence and inconsistent results were observed when different batches of the crude taurocholate from the same or different sources were used. Similarly, &bgr;‐glucosidase activity from Gaucher splenic tissue homogenates, supernatant fluids (40,000 x g) and residue pellets was preferentially inhibited by purified sodium taurocholate. These findings indicate that the reliability and sensitivity of the enzyme assay for Gaucher's disease can be enhanced by determining &bgr;‐glucosidase activity in both the absence and presence of purified sodium taurocholate, particularly when variant cases with relatively high residual enzyme activity are encountered. In contrast to the enzyme from fibroblasts and spleens, &bgr;‐glucosidase activity from human placenta was markedly activated (> 300%) by the presence of 0.08% (1.49 mM) purified sodium taurocholate or 0.1 mM phosphatidyl serine, suggesting the presence of a predominate form of &bgr;‐glucosidase, possibly glucocerebroside &bgr;‐glucosidase, which is activated by the detergent. The apparent Michaelis constant (Km) for both the soluble and membranebound enzyme from normal fibroblasts was 1.6 ± 0.1 mM. Kms from a patient with severe juvenile Gaucher's disease and two other patients with milder manifestations were 0.8 ± 0.2 and 3.3 ± 0.3 mM, respectively.SpeculationThe observation that &bgr;‐glucosidase activity from tissues of patients with juvenile onset forms of Gaucher's disease is preferentially inhibited by the detergent, sodium taurocholate, suggests that a structurally altered‐&bgr;‐glucosidase, which is more susceptible to inhibition by sodium taurocholate, is synthesized in patients with the disease. The severity of the disease could depend on the particular amino acid affected in the primary structure of the enzyme. An alternate explanation is the presence of at least two enzymes, which may or may not be isozymes, each capable of releasing glucose from the artificial fluorogenic substrate, but only one, which is deficient in Gaucher's disease, can hydrolyse the natural substrate and is unaffected by the presence of sodium taurocholate.

ISSN:0031-3998    

出版商:OVID    

年代:1980

数据来源: OVID

摘要:

SummaryIn order to better understand the factors determining serum levels of IgD, total serum IgD and IgE were studied in 23 nonallergic twin pairs, consisting of 16 monozygotic (Mz) and 7 samesex dizygotic (Dz) pairs. Both immunoglobulins were measured by a paper disc solid phase radioimmunoassay, sensitive to 1 ug/dl of IgD and 1 I.U./ml of IgE. Also studied were 10 paired sera taken at different times from 10 healthy subjects of similar mean age to the twins and 21 randomly paired sera from unrelated subjects.The intrapair variance of both serum IgD and serum IgE levels were significantly less in Mz than in Dz twins (P< 0.05). Thus, there appears to be a genetic influence over serum IgD levels, probably to a similar degree to that previously shown to exist for serum IgE levels. Heritability was calculated to be 0.759 for IgD and 0.697 for IgE. Also, the intraclass correlation coefficient (rI) for IgD in monozygotic twin pairs was 0.9370 (P< 0.0001) and for IgE was 0.8602 (P< 0.001). It appears likely that the number of genetic loci controlling serum IgD levels is similar to, or less than, the number controlling serum IgE levels because the random pair/Dz pair variance ratio was lower for IgD than for IgE.SpeculationBecause serum IgD can now be measured accurately in all normal subjects, including newborn infants, it should be possible to determine not only the effect of heredity on serum levels but also the effect of specific diseases, infections, antigen exposures, growth, changes in the levels of other immunoglobulins, immunosuppressive agents, and other environmental influences. This will increase the understanding of the immunobiologic role of IgD, and will also facilitate interpretation of measurements of specific serum IgD antibodies and of cell surface IgD.

ISSN:0031-3998    

出版商:OVID    

年代:1980

数据来源: OVID

ISSN:0031-3998    

出版商:OVID    

年代:1980

数据来源: OVID

ISSN:0031-3998    

出版商:OVID    

年代:1980

数据来源: OVID

ISSN:0031-3998    

出版商:OVID    

年代:1980

数据来源: OVID