Biomedical subjects
Publications and source records attributed to G Schmer.
The administration of red cell ghost encapsulated indolyl-3-alkane alpha-hydroxylase (an enzyme which destroys tryptophan by oxidation of the side chains) in CD-1 female mice causes effective tryptophan depletion in plasma and brain and induces hypothermia by probably decreasing the serotonin concentration in brain by decreasing the concentration of its precursor, L-tryptophan.
Polymaleic acid and polyacrylic acid polymers have been covalently linked to indolyl-3-alkane alpha-hydroxylase with a shift of the pH optimum from 3.5 to between 5.0 and 5.5. In addition, the specific activity of the modified enzyme was increased approximately threefold at pH 7.0. The Km values of the polymer-bound enzyme preparations are essentially the same as that of the native enzyme. The plasma half-life was shortened from 6-7 hours with the native enzyme to 2-4 hours with the modified enzymes. The degree of L-tryptophan depletion in the circulation of mice, however, was the same during a 24-hour period after injection of native or modified enzymes.
A method of heparinless, oxygenatorless, left heart bypass perfusion rewarming following surface hypothermia, with the use of a closed circuit with 130 ml. prime volume including heat exchanger, has been devised. The use of polyurethane-polyvinyl-graphite (PPG)-coated tubing has previously been reported. In this text, the use of an athrombogenic coating with cetyl-pyridinium chloride (CPC) as a regional heparin carrier was studied in dogs, comparing groups with PPG tubing and total systemic heparinization or plain polyvinyl tubing without systemic heparinization. Heparin compounded in the CPC coating eluted into the blood and caused mild transient whole-body heparinization during rewarming from 20 degrees to 25 degrees C., as evidenced by prolongation of the thrombin time. Alterations of hematologic parameters in all three groups were similar to those during surface rewarming except for those affected by heparinization. The left heart bypass method was found useful for hypothermic open-heart surgery when utilized with an athrombogenic surface coating or total body heparinization. It was concluded that the CPC coating is superior to the PPG coating since no cracking surface develops, it is translucent, and it provides a more effective athrombogenic surface.
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Indolyl-3-alkane alpha-hydroxylase was isolated from soil isolate organism, Pseudomonas XA, by affinity chromatography on indolyl-agarose, using different indole derivatives (L-tryptophan, N-acetyl-L-tryptophan, indole-3-carboxaldehyde and 3-indole-acrylic acid). With the exception of N-acetyl-L-tryptophan-agarose, excellent yields were obtained. The affinity chromatography step caused a 15-fold increase in the specific activity of the enzyme. The purity of indolyl-3-alkane alpha-hydroxylase was comparable to the preparations obtained by conventional isolation techniques; however, it showed a 7- to 10-times higher overall yield. Affinity purified indolyl-3-alkane alpha-hydroxylase exhibited essentially one band in polyacrylamide gel electrophoresis and on isoelectric focusing.
Desialised orosomucoid (alpha-1-acidic glycoprotein) was coupled to Pseudomonas 7A glutaminase-asparaginase by glutaraldehyde, iodinated and injected into mice. The half-life of radioactivity and glutaminase activity in plasma was about 7 min. Radioactivity and glutaminase activity in the liver reached a peak at about 20 min. The radioactivity in liver then declined with a half-life of about 20 min. Enzyme activity in liver declined with a half-life of about 10 min. The ratio of enzyme activity to radioactivity was lower in the liver than in plasma at all times during the experiment, indicating rapid hepatic inactivation of the enzyme. Uptake into the liver could be blocked by excess desialised orosomucoid. Glutamine levels in the liver were about 10% of normal for 44 min but returned to 50% of normal by 93 min. Intestines, kidney and spleen failed to exhibit any appreciable uptake of desialated orosomucoid glutaminase-asparaginase.
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Complement component C3, component C4, and total hemolytic complement CH50 were measured in blood from ten patients with acute disseminated intravascular coagulation (aDIC) syndromes. The study group was selected on the basis of history to exclude antecedent immunologic, infectious, or hepatic disease. The mortality rate was high (90%), the average duration of illness short (8.5 days), and the utilization of blood products extensive. The behaviors of C3 and C4 were found to be analogous to fibrinogen, plasminogen, antiplasmin, and platelets. CH50 activity paralled C3 and C4, as well as results of the soluble coagulation factor screening tests. It is concluded that serum complement is consumed as part of the multisystem dysfunction, aDIC, and that in conjunction with traditional indicators it may be utilized to gauge the severity of this syndrome.
The caseinolytic activity of one CTA (Committe on Thrombolytic Agents) unit of human plasmin is inhibited by a series of plasma dilutions containing antiplasmin. Then neutralization of the standard plasmin by increasing amounts of antiplasmin shows a steeper linear decrease of plasmin activity betwwen 1.0 and 0.5 CTA units and a much smaller further inactivation below 0.5 CTA units. It is thought that the standard plasmin is partially damaged at the antiplasmin combining site during the purification procedrue and might be responsible for the differences in plasmin-antiplasmin neutralization in the standard curve. Using the steeper slope of the plasmin neutralization curve, an average of 8.6 +/- 1.0 CTA units plasmin neutralizing activity per ml human plasma was found in 36 healthy donors. The difficulty of obtaining 'native' standard plasmin with full antiplasmin combining capacity represents the main problem of a reproducible reliable antiplasmin assay.
Human and bovine antithrombin II/III have been isolated by a simple procedure essentially using only affinity chromatography on heparin-agarose and polyethylene glycol precipitation. An additional ammonium sulphate step removes polyethylene glycol and trace contaminants. The final preparation is homogeneous by SDS-, disc- and agar slide electrophoresis. End group analysis of human antithrombin II/III shows histidine as the N-terminal amino acid. The pure preparation showed both progressive antithrombin activity and heparin cofactor activity.