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Biomedical subjects

M Hauck

Publications and source records attributed to M Hauck.

49 records · Page 3Linked to original sources
PubMed1981

The interaction between chymotrypsin and horse leucocyte neutral proteinases inhibitor.

The inhibition of alpha-chymotrypsin by horse leucocyte neutral proteinases inhibitor was time-dependent with synthetic substrate N-benzoyl-L-tyrosine ethyl ester but not with azo-casein. This time dependence could be used to calculate the rate constant kass for the association of the inhibitor with bovine alpha-chymotrypsin (kass = 0.3 X 10(6)M-1 S-1). The inhibitor reacted with chymotrypsin at a molar a ratio of 1 : 1. The dissociation constant Ki = 0.30 X 10(9)M of the complex indicates a very strong interaction between enzyme and inhibitor.

Animals↗
PubMed1980

Purification and characterization of the elastase-like enzyme of the bovine granulocyte.

The extracts of granules isolated from bovine granulocytes show elastase- and chymotrypsin-like activities, as detected with specific synthetic substrates. Extraction of these enzymes depends upon salt concentration. In the course of the present studies a 21-fold purification of the elastase-like enzyme was achieved on a (Ala)3-CH-Sepharose 4B gel. The molecular weight of the enzyme is 33 000, as determined by gel electrophoresis in the presence of sodium dodecyl sulfate. The elastase-like activity is inhibited by phenylmethylsulfonyl fluoride, soybean trypsin inhibitor, basic pancreatic inhibitor and by heparin at different rates. Elastatinal inhibits the enzyme competitively (Ki = 80 microM). The cytosol of bovine granulocytes contains a protein which strongly inhibits the elastase-like enzyme of the bovine granulocyte (Ki = 0.4 nM) as well as porcine pancreatic elastase (Ki = 11 nM).

Animals↗
PubMed1980

The effect of uraemic "middle-sized molecules" on T lymphocyte functions.

The activity of the leucocyte inhibitory factor (LIF) stimulated with Concanavalin A was examined in chronic uraemic, haemodialysed patients. It was found that the LIF activity decreased in chronic uraemic patients as compared with the normal controls. The absolute T lymphocyte count and active E rosette formation also decreased. In in vitro experiments the authors have also examined the inhibitory effect of the so-called "middle-sized molecule" (MSM) on uraemic materials separated from the serum and the haemofiltrate. They observed that the materials with a molecular weight of 1000-1500 isolated both from the serum and the haemofiltrate significantly inhibited the Con A stimulated LIF production of normal lymphocytes and decreased the ratio of the active E rosette-forming T lymphocytes. On the basis of their experiments the MSM uraemic materials are considered responsible for the decreased immune reactivity of uraemic patients. These uraemic toxins can be dialysed.

Adult↗
PubMed1980

HLA--C antigens on platelets.

The direct demonstration of HLA-C antigens Cw2, Cw-3, and Cw4 on human platelets is described. The antigens were detected by means of a platelet radioimmune anti-IgG test using acid eluates from platelets and lymphocytotoxic antisera. It is concluded that HLA-C determinants are only weakly expressed on platelets. Individual differences observed reflect antigenic variations.

Antibodies, Anti-Idiotypic↗
PubMed1979

Fragmentation of actin by thrombin-like snake venom proteases.

The effect of thrombin-like snake venom proteases (Ancrod of Agkistrodon rhodostoma and Batroxobins of Bothrops moojeni and Bothrops marajoensis) on skeletal muscle actin was studied and compared to the thrombic cleavage of this protein. Only EDTA-pretreated G- and F-actin were split by thrombin and Ancrod, while Batroxobins hydrolyzed native G-actin, too. The time course of digestion was followed by sodium dodecyl sulfate polyacrylamide gel electrophoresis. A split product of 37 500 daltons appeared first which was cleaved further resulting in three lower molecular weight fragments. The sodium dodecyl sulfate gel pattern of thrombic fragmentation was well distinguishable from those caused by Ancrod and Batroxobins. The first split products of Batroxobin digestion--a smaller peptide and the 37 500 dalton fragment--were isolated and by estimating their N-, and C-terminal end groups and amino acid compositions the peptide bond hydrolyzed first was located in the primary structure of actin. It was established that while thrombin split off two actino-peptides (at Arg(28)-Ala(29) and Arg(39)-His(40) from the N-terminal end of the molecule only Arg(39)-His(40) was cleaved by Batroxobins.

Actins↗
PubMed1979

[Examination of lymphokines in patients with hemodialysis (author's transl)].

The activity of LIF after Con A stimulation was examined in patients with hemodialysis and chronic uremia. It was found that LIF activity is reduced in uremia compared with healthy controls. The absolute number of T lymphocytes was reduced as well as the number of active E rosettes. An inhibitory effect was found in vitro by isolated middle molecules from uremic serum and ultrafiltrate. The LIF production of normal lymphocytes and the number of active rosettes are significantly reduced by substances isolated from serum and ultrafiltrate with molecular weight of 1 000 to 1 500 Dalton. The authors think that these uremic middle molecules are responsible for the already known reducing of immune response by uremia. The uremic substances are dialysable.

Adult↗
PubMedDate not supplied

[Determination of cyclamate in complex matrix using HPLC after column derivatization with 4-fluoro-7-nitrobenzofurazan].

A method for the analysis of cyclamate in complex foodstuffs has been developed. This method is applicable in strongly coloured and protein-rich foodstuffs. The quantitative determination depends on oxidation of cyclamate to cyclohexylamine and derivatisation with 4-fluoro-7-nitrobenzofuran (NBD-F). The derivatives are analysed by HPLC on a C18: reversed-phase column, their minimal stability being 12 h. There are two possible methods of detection: (a) absorbance at 485 nm and (b) fluorescence with excitation at 485 nm and emission at 530 nm. The detection limit of cyclamate is 5 mg/kg foodstuff, with fluorescence detection 0.4 mg/kg. The recoveries are in the range of 88% to 104%.

4-Chloro-7-nitrobenzofurazan↗
PubMedDate not supplied

Age-dependent variations of human PMNL elastase activity as a function of pH, ionic strength and calcium concentration.

Human leukocyte elastase (HLE) has been implicated in the pathomechanism of various diseases, such as emphysema and atherosclerosis. The incidence of these diseases is increasing with aging. Therefore, it can be supposed that the HLE activity is changing with aging according to the well known age-related physiological alterations. Thus, the effects of pH, NaCl and calcium concentrations on HLE activity, separated from polymorphonculear leucocytes (PMNLs) of healthy, young (<35 years) and elderly (>75 years) subjects, were studied by measuring the activity with synthetic substrate and with bovine and human atherosclerotic and non-atherosclerotic aortic elastin. From our results, it may be concluded, that the elastolytic activity of HLE separated from PMNLs of elderly subjects is more sensitive to ionic strength, to pH and to the calcium concentration of the medium, than the HLE activity of young subjects. The elastolytic activity of HLE, of both young and old subjects, increases dramatically on atherosclerotic aortic elastin in the presence of calcium. These findings might explain, at least partly, the increased incidence of atherosclerosis with aging.

Journal Article↗