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Biomedical subjects

N Heimburger

Publications and source records attributed to N Heimburger.

At least 55 records · Page 3Linked to original sources
PubMed1981

Effect of human granulocytic elastase on isolated human antithrombin III.

The interaction of elastase isolated from human granulocytes with purified human antithrombin III was investigated. Antithrombin III did not display any inhibitory effect on granulocytic elastase. Dependent on enzyme concentration, however, granulocytic elastase induced progressive inactivation of antithrombin III leading to an almost complete loss of the thrombin inhibitory activity at a molar ratio of elastase: antithrombin III = 0.4:1 within 5 min at 25 degrees C. Antithrombin III is not drastically degraded by elastase as revealed by polyacrylamide gel electrophoretic and rocket immunoelectrophoretic investigations. However, characterization by two-dimensional immunoelectrophoresis with heparin in the first dimensional gel layer revealed a distinct change in the electrophoretic mobility of the inhibitor preincubated with elastase compared to native antithrombin III. This indicates that heparin binding sites of antithrombin III are occupied or affected by the elastase-induced peptide bond cleavage(s). Granulocytic proteinase inhibitors (eglin, Bowman-Birk inhibitor) proved to be highly effective in preventing the antithrombin III inactivation by degradation due to elastase. It is assumed that at least part of the antithrombin III consumption in diseases such as septicemia or endotoxemia is due to proteolysis by granulocytic proteinases. Application of specific inhibitors in the early phase of these ailments should be able to prevent this unspecific degradation of the endogenous antithrombin III.

Antithrombin III↗
PubMed1981

[Factor VIII concentrate, highly purified and heated in solution (author's transl)].

A process is described to produce a highly purified factor VIII concentrate heated in solution. Pooled cryoprecipitate from citrated plasma is adsorbed on aluminum hydroxide gel. The fibrinogen is removed by heat denaturation in the presence of glycine; factor VIII is precipitated with sodium chloride from the supernatant. The precipitate is dissolved in a saccharose/glycine solution and heated at 60 degrees C for 10 h. The factor VIII is then separated by further precipitation with sodium chloride, the precipitate dissolved, dialysed and sterilized by filtration. The factor VIII concentrate contains approximately 6 units F VIII:C per mg protein. the ratio of F VIII R:Ag/F VIII:C is 3. The product is free from coagulable protein and gamma-globulins. The efficacy of the heating step in the reduction of the hepatitis B-infectious titre was proved in chimpanzees. For this purpose, hepatitis B virus was added to the pooled cryoprecipitate.

Drug Stability↗
PubMed1978

Human plasma kallikrein: purification, enzyme characterization and quantitative determination in plasma.

Human plasma kallikrein was isolated from a plasma fraction related to Cohn fraction IV4 by affinity- and Sephadex G-150 chromotography yielding a material with 17.3 TAME-U/A280 unit. The preparation was characterized by immunological and enzymatic methods. Complex formation with alpha2-macroglobulin, C1-inactivator and aprotinin was demonstrated by immunoelectrophoresis. The bradykinin release from high-molecular weight kininogen and its inhibition by antibodies to kallikrein, AT III and AT III-heparin complex were measured using a biological test system (rat uterus). Time dependent inactivation of kallikrein by AT III, and AT III-heparin complex was shown by means of a synthetic kallikrein substrate: Bz-Pro-Phe-Arg-pNan. The same substrate was used to measure the activation of prekallikrein in plasma by kaolin and F XII a. Antibodies raised against kallikrein were shown to inhibit the reaction specifically. A quantitative determination of plasma prekallikrein by electroimmunodiffusion according to Laurell was developed: the plasma concentration in normal individuals was found to be 1.8 - 2.2 TAME-U/ml related to kallikrein activity; this corresponds approximately to 9 - 11 mg antigen/100 ml plasma.

Animals↗
PubMed1976

[Plasminogen estimation as a routine test (author's transl)].

A simple method for the routine determination of plasminogen using the coagulation time is described. 0.2 ml of plasminogen reagent and 0.1 ml of sample plasma, prediluted 1:200, are incubated for 3 minutes at 37 degrees C. 0.05 ml of diluted test thrombin are then added and the coagulation time is measured. It is converted into percent of normal using a standard curve. The test correlates with an immunological method in healthy probands (r = 0.96). Initial measurements in 160 patients show that knowledge of the plasminogen titre may also be of interest outside the problems of haemostasis.

Blood Coagulation Tests↗
PubMed1976

Localization of low molecular weight acrosin-trypsin inhibitors in the boar genital tract by immunofluorescence.

Using the indirect immunofluorescent technique, the occurrence and distribution of the low molecular weight acid-stable acrosin inhibitors from boar seminal plasma (BSAI) in the boar genital tract was studied applying specific inhibitor-directed rabbit-immunoglobulins. The acrosin inhibitors are localized in the mucosa cells of the cauda epididymis, the vas deferens, the seminal vesicles, the urethra and distinct glandular units of the prostate. The wide distribution of the acrosin inhibitors within the boar genital tract indicates a protective function towards the destructive proteolytic potential of acrosin liberated e.g. during sperm aging from desintegrating spermatozoa.

Acrosin↗
PubMed1976

Factor-VIII-related antigen and cold-insoluble globulin in leukemias and carcinomas.

An elevated plasma level of the factor-VIII-related antigen is not specific for leukemias and malignancies but is also observed in inflammations and in rheumatic diseases. As a reason for this nonspecific change an increased tissue breakdown has to be considered as well as an impaired elimination of the protein, possibly in some cases in the course of a consumption coagulopathy. The plasma levels of the cold-insoluble globulin were reduced in chronic lymphatic leukemias and in acute inflammations, but elevated in rheumatic diseases. Production and liberation of the cold-insoluble globulin may not only be changed by malignant transformation of cells but also by inflammatory and infectious processes.

Antigens↗
PubMed1975

[Experimental studies on proteolysis of hyaline membranes in vitro (author's transl)].

The incubation of lung tissue from premature infants with pulmonary hyaline membranes in fibrinolysis activating or fibrinolytically active solutions gave the following results. With streptokinase it was not possible to dissolve hyaline membranes (verification of the physiological lack of plasminogen in premature infants). The mean content of membranes after 24 hours showed to be 18.14 +/- 12.43% which almost corresponded to the control value of 20.24 +/- 10.54% after incubation in NaCl-solution. In comparison, solutions of plasmin, plasmin-activator or activator prepared from proactivator-plasminogen through activation with streptokinase led to a clear reduction in the membrane content, i.e. 11.00 +/- 6.50, 13.89 +/- 9.72, and 13.63 +/- 8.94%, respectively. A decrease in membranes equally strong to that after plasmin appeared after incubation for only 12 hours in trypsin (11.09 +/- 8.62%). Plasmin, plasmin-activator, and activator, but not streptokinase alone, caused also a considerable nonspecific proteolysis of the lung parenchyma which was equal to the trypsin effect, for example, with an only half as long incubation time. Since the lungs of premature infants contain the tissue activator of fibrinolysis we discuss the suggestion of Ambrus et al. (1974) to administer an injection of plasminogen to premature infants immediately after birth so that a spontaneous fibrinolysis can be favoured for developing hyaline membranes.

Chymotrypsin↗