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Biomedical subjects

H Struck

Publications and source records attributed to H Struck.

At least 19 recordsLinked to original sources
PubMed1989

[Collagen antibodies and their effect on wound healing].

The influence of antibodies to collagen on wound healing was tested by the use of a standard incision wound in rats. The antisera--specific for the terminal determinants of the collagen molecule--were obtained from rabbits immunized with rat--or pig--skin collagen and injected intraperitoneally, i.e. systemically. Generalized immune reactions or signs of incompatibility were not observed. The injection of antisera on the 7th postoperative day led to a significant gain of tensile strength. This effect was achieved by the homologous antiserum (p less than 0.01) as well as by the heterologous antiserum (p less than 0.04). The heterologous antiserum further induced a significant fall of free serum hydroxyproline (p less than 0.005). The application of the heterologous antiserum on the 14th postoperative day caused a significant decrease of tensile strength (p less than 0.006). The results are referred to collagen-specific immune reactions and varying conditions in the wounded area during different phases of wound healing.

Animals↗
PubMed1987

Effects of the hormone relaxin on the metabolism of the glycosaminoglycans in the mouse symphysis pubis.

The influence of the peptide hormone relaxin on the glycosaminoglycan (GAG) metabolism was investigated in the pubic ligament of the symphysis pubis and in serum of the virgin mouse. Fresh weight DNA and GAG content per 1 ligament is significantly increased, the level of water soluble protein is not affected. A shift in the electrophoretic GAG pattern by an increasing amount of hyaluronic acid and a decreasing amount of chondroitin sulfate and dermatan sulfate can be observed. Concerning GAG-splitting enzymes (N-acetylglucosaminidase, arylsulfatase, beta-glucuronidase) the N-acetylglucosaminidase reveals a significant increase of its activity in the interpubic ligament and in the serum. The data demonstrate that relaxin treatment induces some changes in the GAG metabolism.

Acetylglucosaminidase↗
PubMed1982

Amino acid-p-nitroanilide and -beta-naphthylamide cleaving activities in rat serum.

Determination of proteolytic activities gains increasing importance for the diagnosis of various pathologic conditions. Many questions can only be solved with the aid of experiments with animals. In preparation of such studies the pattern of the enzymatic hydrolysis of 20 amino acid-p-nitroanilides and one -beta-naphthylamide by normal rat serum was measured. The pH dependences of the single reactions are reported as well as their sensitivity to the action of ethylenediaminetetraacetic acid, dithioerithrol, and puromycin. Additionally, it is shown that collecting of the blood by cardiac puncture and preparation of the native plasma is the best way to get reproducible results.

Amino Acids↗
PubMed1981

[Comparative evaluation of hydroxyproline in urine and in serum as a possible clinical parameter for radiation-induced destruction of connective tissue due to fractionated radiation therapy (author's transl)].

In the course of postoperative fractionated radiation therapy hydroxyproline was evaluated as a biochemical parameter of radiation damage in 60 patients with different tumour diseases. At different times before, during and after therapy, hydroxyproline in serum was evaluated according to the method of Dabew and Struck, hydroxyproline in urine according to the test combination "hypronosticon" (Organon-Technika). There was no correlation to be found between hydroxyproline in serum or urine, clinical course of disease and radiation dose. Possible explanations were discussed.

Cobalt Radioisotopes↗
PubMed1980

Hydrolysis of some cystine amniopeptidase and aminopeptidase substrates by human placental enzymes after isoelectric focusing.

Several cystine aminopeptidase- and aminopeptidaselike activities of mature human placenta were demonstrated by chromatography on CM-Sephadex and subsequent preparative flat bed isoelectric focusing. Enzyme tests were carried out by using a micro modification of the Bratton-Marshall reaction with seven amino acid-rho-nitroanilides and one amino acid beta-naphthylamide as substrates. By this method three main activities were detected; each was nonhomogeneous and capable of hydrolyzing cystine aminopeptidase- as well as aminopeptidase substrates. The substrates benzyl-cystine-rho-nitroanilide, cystine di-rho-nitro-anilide and cystine di-beta-naphthylamide were split by different enzymes. By studying the effects of several effectors or of heating, no enzyme with the properties described in the literature for serum cystine aminopeptidase could be unequivocally demonstrated. The results report here suggest that serum cystine aminopeptidase--in contrast to placenta cystine aminopeptidase--is either altered severely in its structure or that it represents a multiplicity of enzymes, which attack "specific" substrates and are therefore jointly manifested as cystine aminopeptidase.

Aminopeptidases↗
PubMed1979

Purification and properties of a collagen peptidase (PZ-peptidase) from rabbit serum.

A peptidase cleaving a synthetic substrate for collagen peptidases, 4-phenylazobenzyloxcarbonyl-L-Pro-L-Leu-Gly-L-pro-D-Arg (designated as PZ-peptide) has been purified 1200-fold from rabbit serum and characterized. The enzyme preparation is free of collagenase and unspecific proteinase activity. The natural substrates are denatured collagen and collagen peptides. The peptidase has a molecular weight of 124 000 and an isoelectric point at pH 5.1. The pH dependence curve exhibits two maxima, one at pH 7.1 and the other at pH 7.9. The enzymic reaction is completely inhibited by Zn2+ and to a slower degree by Hg2+, Mn2+ and p-hydroxymercuribenzoate. It is not affected by EDTA and KCN but totally blocked by o-phenanthroline. Phenylmethylsulfonylfluoride is completely inhibitory and points to a serine residue in the active site.

Animals↗
PubMed1979

[Inhibition of PZ-peptidases by serum (author's transl)].

The inhibition of two PZ-peptidases by several sera was studied with the aid of methods based on the PZ-peptidase assay of Wünsch and Heidrich Clostridiopeptidase A is inhibited by all sera, whilst the PZ-peptidase from the rabbit serum is inhibited only by heterologous sera. The inhibition is weak and cannot be compared with the strong serum inhibition shown by collagenases.

Animals↗
PubMed1979

Relaxin and collagen metabolism.

The influence of the peptide hormone relaxin on collagen metabolism was studied in the symphysis pubis of the mouse. In the tissue the content of water and of acid soluble collagen in relation to total collagen is increased by hormonal treatment. Total collagen calculated in relation to the dry weight is decreased. Collagenase which was also detected in the symphyses of the controls is slightly enhanced. In serum collagen peptidase and collagen peptidase inhibitor as well as cyclic AMP exhibit distinctly increased levels. The effects can be suppressed by administration of relaxin-specific antisera. The data make clear that in the symphysis relaxin activates the collagenolytic system.

Animals↗
PubMed1979

N-Acetylaminoacyl-p-nitranilidase from human placenta. Purification and some properties.

An enzyme hydrolyzing N-acetylaminoacyl-p-nitroanilides has been isolated from mature human placentae by a six-step procedure comprising extraction from a placenta homogenate, ammonium sulfate fractionation, treatment with isopentyl alcohol, chromatography on CM-Sephadex, protamine sulfate precipitation and gel filtration on an Ultrogel AcA 34 column. About 2500-fold enrichement was achieved from placenta homogenate. The purified enzyme preparation showed a single band on polyacrylamide disc electrophoresis. The molecular weight was estimated to be 380,000 by gel filtration. Placental extracts contain two main isoenzymes of pI 3.9 and 4.5 respectively. Activity was strongly inhibited by chloromercuribenzoate, slightly inhibited by Ca2+ and cysteine; no activation could be detected. The enzyme exhibits an exopeptidase-like activity towards acetyl-dipeptides with a certain specifity towards N-acetylalanyl-alanine; N-acetylalanine-p-nitroanilide, however, is hydrolyzed four times faster. With N-acetylalanine-p-nitroanilide as substrate the pH optimum was 8.0--8.2; Km was 2.13 mmol/l. N-Acetylleucine-p-nitroanilide and N-acetyltyrosine-p-nitroanilide were split slowly; N-acetylalanyl-alanyl-alanine-p-nitroanilide, N-butyloxycarbonyl-alanyl-alanine-p-nitroanilide, unsubstituted analogous aminoacyl-p-nitroanilides and several protein substrates were not hydrolyzed. The functions of the enzyme are still unknown.

Aminopeptidases↗
PubMed1979

[Effect of exogenous collagen on the metabolism of burns in rats; the collagen treatment of large superficial excision wounds].

In an animal experiment study the effect of collagen sponge treatment on skin wounds was examined. In a test for defense mechanism, the bandage material was accepted without any disturbance of the surrounding tissue. It could also be removed without any damage to the wound area while renewing the covering bandage. In contrast to the controls, there was a statistically significant difference in the decreasing wound area. No tract formation of the wound edges was observed in the experimental group, and histologically the wounds showed an earlier fiber formation with functional orientation toward the wound surface. The advantages of treatment using collagen instead of inert material include better compatibility, a positive cosmetic effect, and a stimulation of wound healing without the necessity of a two-stage transplantation.

Animals↗
PubMed1978

[Proteolytic activities in mature human placenta. II. Neutral peptidases and PZ-peptidase (author's transl)].

Continuing our contributions on proteases of human placenta we enriched some unidentified neutral peptidases by chromatographying freeze dried placenta extracts on CM-Sephadex, followed by preparative isoelectric focusing and chromatography on Ultrogel. By this procedure two Acetyl-aminoacyl-p-nitranilidases, three Ala-Ala-p-nitranilidases, one Benzyloxycarbonyl-Ala-Ala-p-nitranilidase, one Carbobenzoxy-Gly-Pro-Arg-p-nitranilidase and one PZ-peptidase could be characterized in greater detail. Here molecular weights, isoelectric points and pH-optima of these enzymes are reported.

Chromatography↗
PubMed1978

[Mechanical aspects of bone stability by an in vivo testing method (author's transl)].

This is a report of a new method for in vivo determination of the Young modulus of human os radii. The failure of the apparatus is +/- 1.86 per cent. The accuracy of the measuring procedure on healthy subjects bases on a variation coefficient of nearly 10 per cent. 124 forearms of healthy persons had been studied in relation to age, sex and to the right and the left os radii. There was a statistically significant higher elastic property of the bones of adolescent versus elder men (over 60 years), but no significant differences between male and female. Right and left os radii had nearly the same amounts for the Young modulus.

Adolescent↗
PubMed1978

[Xanthinol nicotinate and wound healing].

In an experimental study the local effect of i.v. applied xantinol-nicotinate (Complamin) on healing skin incisions in rats was studied. In conclusion, there was a higher ultimate tensile strength of wounds treated by the agent, based on the increased synthesis of collagen fibres. This statement was proved by the alteration of free hydroxyproline in serum. Histologically, there was an intensive vascularization of the wound healing area. Concerning the elastic behaviour we found a more rigid regenerative tissue in the early phases of healing on account of the enhanced thickness of the wound area.

Animals↗
PubMed1978

[Effect of exogenous collagen on the metabolism of rat burns].

Standardized burns on rats were treated with 14C-labeled collagen from guinea pig skin. Collagen fractions of different solubility were extracted from the wounds during healing and the incorporation rates were measured. In the neutral salt-soluble fraction, maximal specific activity was found on day 7 after application of the burns; 1,65% of the applied label was incoporated, and it was calculated that 11,8% of the total neutral salt-soluble collagen of the wounds originated from the applied exogenous collagen. In the citric acid soluble collagen, maximal specific activity was observed on day 9; 1,48% of the applied label was incorporated; 6,0% of total citric acid-soluble collagen of the wounds was derived from the exogenous collagen. In the insoluble collagen, no significant increase in radioactivity was observed before day 14 after burning. The results support the opinion that exogenous collagen is used for substitution in connection with endogenous collagen synthesis.

Animals↗
PubMed1977

[Relaxin and cervical dilatation during parturition (author's transl)].

Relaxin concentrations during pregnancy and parturition were measured in tissue specimens of the uterine cervix of 27 women in childbearing age. During pregnancy relaxin levels increase from 0.4 guinea pig unit (GPU) to 0.94 GPU/mg soluble tissue protein. Already during parturition (0.41 GPU) and immediately post partum (0.39 GPU) the hormone concentrations have dropped back to normal. It appears that the biochemical changes which occur in the connective tissue of the uterine cervix during pregnancy and parturition are influenced by relaxin. Experimental animals were taken to show if relaxin acts by activation of collagenolytic enzymes. In the mouse a rise in the activity of collagen-peptidase and of the inhibitor of collagen-peptidase in plasma was found after subcutaneous injections of relaxin. The addition of human cervical tissue extracts resulted in an increase of enzyme-activation (even higher than could be expected of the hormone concentrations of the individual extracts). The highest levels of the enzyme were found after injections of extracts from cervical tissue specimens of parturient women.

Animals↗