Biomedical subjects
Publications and source records attributed to H Struck.
A simple procedure for the purification of the peptide hormone relaxin is described. It allows prepare with good yield highly purified relaxin of an activity of 700 GPU/mg protein. For the first time ion-exchange chromatography by Amberlite IRA-410 and subsequent gel filtration on sephadex G-25 fine were used as purifications steps.
Total hydroxyproline in urine and free hydroxyproline, free and peptide hydroxyproline and protein bound hydroxyproline in serum are measured during wound healing in rats. The free and free+peptide fractions vary in concert with each other and with urine hydroxyproline. Protein bound hydroxyproline fractions take a very different course and behave as an acute phase reactant. The results suggest that protein bound hydroxyproline does not mirror collagen turnover but may be more relevant to C1q or complement metabolism.
Proteolytic activities of human placental extract are determined with the aid of a sensitive micromethod, based upon the Bratton-Marshall-reaction, and aminoacid-p-nitroanilides as substrates. The activities are differentiated by using 19 substrates, by adding 10 effectors, and by incubating the assays within the pH-range from 6.0--8.4. Besides Oxitocinase- and Aminopeptidase-like activities, a very active neutral peptidase, so far unknown in human placenta, an acid peptidase, e.g. Cathepsin C or Dipeptide-aminopeptidase II, and some other enzymes, not yet indentified by us, are demonstrated.
Proteolytic, arylamidase-like activities of human serum are determined by using a sensitive micromethod, based upon the Bratton-Marshall-reaction, and amino acid-p-nitroanilides as substrates. Besides the alanine-aminopeptidase and the oxytocinase, the dipeptide-aminopeptidase II, a neutral peptidase, and 6 other peptidases, not yet identified by us, are differentiated with the aid of 19 substrates, by adding 8 effectors, and by incubating the enzyme tests within the pH range 6.0 to 8.4.
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The effect of exogenous factor XIII on fracture healing has been tested. It could be shown that after administration of the fibrin stabilizing factor, the concentration of fibrin fibres in the fracture haematoma increases. The resistance against breaking is thus enhanced in treated animals as compared to untreated controls, mainly during the early phases of fracture healing. X-ray diagnosis demonstrated an enhanced healing process of the treated fractures. The accelerated fracture healing by factor XIII adminstration could also be substantiated through histological examinations.
Skin wounds of rats were treated by 14C-labeled collagen from guinea pig skin. The main portion of the applied collagen persisted in the wound area. In the neutral salt soluble collagen maximal specific activity was measured on day 4 after treatment, in the citric acid soluble and in the insoluble collagen at later times. On day 4 after treatment 3.42% of the applied label was found in the neutral salt soluble, 1.43% in the citric acid soluble and 1.40% in the insoluble collagen. The findings suggest that the stimulation of wound healing which is reported by various authors is caused by the incorporation of the applied collagen into the regenerating connective tissue.
Modified methods for the determination of bound hydroxyproline in blood are presented. The fractionated and hydrolyzed samples are separated from interfering material by ion exchange chromatography. Internal standards are used to correct for recovery. After a several fold concentration of samples it is possible to work with reduced blood volumes. Up to 6.12 mumol/l of free and peptide-bound and 11.5 mumol/l of protein-bound hydroxyproline are detectable. Using the described methods hydroxyproline was determined in a pooled human plasma and in the sera of rats.
Collagen prepared from rat, calf, or pig skin was tested on guinea pigs for active cutaneous anaphylaxis. Only one fraction of calf skin collagen gave a slight, positive reaction. No positive reactions were observed in 21 subjects submitted to patch tests and 12 subjects submitted to scratch tests with pig skin collagen. Therefore preparations of pig skin collagen may be used for wound treatment without any risk.
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The influence of rifamycin SV on the healing process of a wound was studied in animal experiments. Measurement of the degree of cicatrization, determination of the free hydroxyproline in serum, and histological findings helped to demonstrate that local application of rifamycin SV leads to an increased fibrinous conglutination of the lips of the wound at an early phase of the healing process and the subsequent formation of fibres in the regenerative tissue is not impaired.
A modification of the Bratton-Marshall reaction for the quantitative determination of enzymically released p-nitroaniline is described. It is very sensitive, easily performed, shows good reproducibility, and it is suitable for routine use in clinical chemistry.
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