Search PubMed⌕ Search

Biomedical subjects

G Schmer

Publications and source records attributed to G Schmer.

At least 55 records · Page 3Linked to original sources
PubMed1979

Use of athrombogenic tubing for perfusion rewarming following surface-induced deep hypothermia.

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.

Animals↗
PubMed1978

Purification of indolyl-3-alkane alpha-hydroxylase by affinity chromatography on indolyl-agarose columns.

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.

Chromatography, Affinity↗
PubMed1978

Kinetics of uptake and activity in mouse liver of glutaminase coupled to desialated orosomucoid.

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.

Animals↗
PubMed1977

Isolation, crystallization, and primary amino acid sequence of human platelet factor 4.

Human platelet factor 4 was purified by a method employing affinity chromatography on heparin/agarose. The amino acid sequence of the protein was determined by automatic Edman degradations and carboxypeptidase Y digestion. There are 70 amino acids in the protein with 5 of the 8 negatively charged residues clustered near the NH2 terminus and 10 of the 13 positively charged residues in clusters of 3 and 4 elsewhere in the protein. Small crystals have been obtained from ammonium sulfate solutions which give a promising preliminary x-ray diffraction pattern.

Amino Acid Sequence↗
PubMed1977

Fibrinogen Seattle: a qualitatively abnormal fibrinogen in a patient with tetralogy of Fallot.

A dysfibrinogen was detected in the plasma of a 14-year-old asymptomatic Caucasian boy who had tetralogy of Fallot. The mutant molecular species could be traced through four generations in an autosomal dominant type of inheritance pattern. Nine of 14 family members were found to have the coagulopathy. Following laboratory and clinical evaluation, the proband underwent radical repair of the cardiac defect without incident. This variant is tentatively designated fibrinogen Seattle pending further characterization.

Adolescent↗
PubMed1977

Clinical use of a totally heparin grafted hemodialysis system in uremic patients.

1. A totally heparin grafted dialysis system shows great promise in the treatment of chronic uremia associated with bleeding risk. 2. Long-term treatment of chronic uremia with this system has to await: a) Further studies of the chronic toxicity of CPC. b) Evaluation of performance which may be achieved by using a more homogeneous heparin with higher bioactivity. 3. Detailed studies of platelet factor 4 release with subsequent heparin neutralization to determine the importance of this variable in its effect on system performance.

Blood Coagulation Disorders↗
PubMed1976

Characterization of human, bovine, and horse antithrombin III.

A comparison of the physical-chemical properties of human, bovine, and horse antithrombin III has been made. These three plasma proteins are strong inhibitors of bovine factor Xa and form a 1:1 molar complex with this coagulation enzyme. Human, bovine, and horse antithrombin III are glycoproteins containing hexose, hexosamine, and neuraminic acid. The total carbohydrate was 9, 12, and 16% for human, bovine, and horse antithrombin III, respectively. These proteins have a similar amino acid composition, although some monor variations were noted. Each antithrombin III is composed of a single polypeptide chain with an amino-terminal histidine residue. Of the first 17 amino-terminal residues, only three differences were noted between the three proteins. These occur in position 2 which is occupied by Gly, Arg, and Trp in human, bovine, and horse, respectively; position 6 which has a deletion in human antithrombin III; and position 8 where Ile in human and horse antithrombin III has been replaced by Val in the bovine preparation. The remainder of the first 17 residues is the same in all three proteins. The molecular weights for the bovine and horse preparation were 56 600 and 52 500, respectively, as determined by sedimentation equilibrium in the presence of guanidine hydrochloride. Some immunological cross-reactivity was also observed between the three different proteins.

Amino Acids↗
PubMed1976

Inhibition of bovine factor IXa and factor Xabeta by antithrombin III.

Factor IXa and factor Xabeta are serine proteases which participate in the middle phase of blood coagulation. These two enzymes are inhibited by antithrombin III by the formation of an enzyme-inhibitor complex containing 1 mol of enzyme and 1 mol of antithrombin III. The complex was readily demonstrated by sodium dodecyl sulfate polyacrylamide gel electrophoresis and loss of coagulant or esterase activity at increasing concentrations of inhibitor. The inactivation of factor IXa by antithrombin III was relatively slow, but the reaction was greatly accelerated by the addition of heparin.

Animals↗
PubMed1976

Complement consumption in acute disseminated intravascular coagulation without antecedent immunopathology.

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.

Acute Disease↗
PubMed1976

Successful use of a totally heparin grafted hemodialysis system in sheep.

A total of 33 totally heparin-grafted dialysis systems using HFAK Cordis Dow Models 3 and 4 have been compared to a total of 23 nongrafted systems. The comparison of deltap, flow rate, FBVL and macroscopic inspection showed highly significant differences in favor of the heparin-grafted systems. The antithrombogenic performance of the totally heparin-grafted systems is mainly due to a small leakage of heparin during the experiments. A minimum of 1.35 X 10(-8) Gm/cm2/min of heparin is sufficient to prevent clotting at the blood-polymer interface.

Animals↗
PubMed1975

Biologic and physical properties of succinylated and glycosylated Acinetobacter glutaminase-asparaginase.

Acinetobacter glutaminase-asparaginase was chemically modified by succinylation and glycosylation with glycopeptides from human fibrin and gamma-globulin. These modifications markedly prolonged the half-lives of the enzyme in mice, rats, and rabbits. The plasma half-life in mice increased with decreasing isoelectric point. Glycosylation caused greater prolongation in rodents than succinylation. The kinetic properties of the modified enzymes were unchanged. Succinylation protected the enzyme from trypsin digestion. Glycosylated preparations had less heat inactivation than native and succinylated enzyme. Sedimentation equilibrium studies on a succinylated preparation showed reversible dissociation to a dimer (71, 400 g/mol) with an association constant of 1.3 times 10-6 liters/mol. This dissociation was identical with native enzyme, except for a 3% increase in molecular weight due to succinate groups. Sedimentation equilibrium studies on glycosylated preparations showed mixtures of molecular weight from 60, 000 to over 180, 000. Gel filtration and active enzyme sedimentation showed active polymers, but no active species smaller than tetramer.

Acinetobacter↗
PubMed1975

A solid-phase radioassay for the quantitative determination of antiplasmin activity in human plasma.

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.

Enzyme Inhibitors↗
PubMed1975

A simple two-step isolation procedure for human and bovine antithrombin II/III (heparin cofactor): a comparison of two methods.

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.

Alpha-Globulins↗