Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0020473 (hyperlipidemia)
 15,891 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Diamine oxidase (DAO) is an enzyme synthesized primarily in the gastrointestinal mucosal cells. Serum levels of DAO have been used as an indicator of the integrity and/or functional mass of the intestinal mucosa. The enzyme is also produced by the placenta and is elevated in newborn serum. Previous radiometric methods for DAO used tritiated putrescine or cadaverine as substrate. A simple and rapid spectrophotometric procedure for DAO with use of histamine as substrate was developed, and this assay was utilized to evaluate the developmental pattern of activity of DAO in umbilical cord blood of newborn full-term and premature infants, in sequential samples from premature infants, and in samples from infants with necrotizing enterocolitis. The spectrophotometric assay was linear to 200 U per L and was also precise with total imprecision (CV) of 11.9 percent and 3.7 percent at DAO activities of 25.6 U per 1 and 126.1 U per L, respectively. Triglycerides above 275 mg per dL caused a significant reduction in measured activity of DAO; however, this effect could be eliminated by use of ultracentrifugation to remove lipemia. Plasma samples with heparin or ethylenediamine tetraacetic acid (EDTA) as anticoagulant were unsuitable for analysis since DAO activity showed a 24 percent and 32 percent decrease in activity at concentrations of 20 U per mL (heparin) and two mg per mL (EDTA), respectively. Serum samples are the specimen of choice. In infants it was found that the serum activity declined to adult levels by day 12 of life and that this decline is not affected by necrotizing arterocolitis.
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PMID:Evaluation of a spectrophotometric method for measurement of activity of diamine oxidase in newborn infants. 150 83

The release of histaminase activity in plasma after small intravenous of heparin was studied in 85 normal subjects and patients. In normal subjects, plasma histaminase activity (basal level, 1.7+/-0.1 U/ml, mean +/-SEM) increased 1.6+/-0.2 U/ml after 10 U of heparin/kg, 8.5+/-2.4 U/ml after 20 U/kg, and 33+/-4.9 U/ml after 75 U/kg. The extent of the increase varied widely among individuals but in a particular individual the response was constant and dose-dependent. Histaminase activity rose to peak levels within 7-15 min and then declined exponentially with a half-life of 40-120 min. This pattern of response was also observed in two patients with the histaminase-producing tumor, medullary carcinoma of the thyroid. A significantly reduced response was observed, however, in 14 patients with type I hyperlipoproteinemia, a disorder in which high plasma triglyceride levels are associated with low postheparin plasma lipolytic activity. After 10 U heparin/kg, plasma histamine activity increased 0.5+/-0.2 U/ml, and after 75 U heparin/kg, 10.9+/-5.6 U/ml. In contrast, in 27 patients with other types of hyperlipoproteinemia in whom postheparin lipolytic activity was normal, the increase (2.4+/-0.6 U/ml) in plasma histaminase activity after 10 U heparin/kg was not significantly different from that of normal subjects. The reduced response of the plasma histaminase activity to heparin in patients with type I hyperlipoproteinemia did not appear to be due to the presence of lipemia or to an inhibitor of the enzyme in plasma. These findings suggest that many patients with type I hyperlipoproteinemia may have deficient release of both lipolytic and histaminase activities into plasma after heparin administration.
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PMID:Response of plasma histaminase activity to small doses of heparin in normal subjects and patients with hyperlipoproteinemia. 419 95