Biomedical subjects

H Pohunková

Publications and source records attributed to H Pohunková.

16 recordsLinked to original sources

PubMed1996

Morphological features of bone healing under the effect of collagen-graft-glycosaminoglycan copolymer supplemented with the tripeptide Gly-His-Lys.

The authors prepared 7.5% and 12.5% collagen gel, and supplemented it with the tripeptide Gly-His-Lys (GHK), perfloxacine and hypersulphated glycosaminoglycan (HSGAG). By means of 125l marking, its absorption was followed from small polyurethane sponges placed under the skin of rats. The absorption of gel without HSGAG was found to be faster. Antibodies against collagen (type I, II and III) or collagen gel were generated either in rabbits or in minipigs, in which collagen gel was tested. Microbiological tests proved the sterility of the collagen gel. The collagen gel supplemented with GHK, pefloxacine and HSGAG was named Colladel, and was used in a model experiment in guinea-pigs for filling artificially created bone defects in diaphyses of femurs, and with cementless endoprostheses. The healing process was followed by means of RTG and NMR, and histologically. The slowest healing process was found in unfilled bone defects. Defects filled with Colladel without GHK healed substantially more quickly, and the most accelerated healing was connected with complete Colladel application. When Colladel was used with cementless endoprostheses, vivid osteogenic activity at the interface of trabecular bone and metal stem was detectable in the course of the experiment.

4-Quinolones↗

PubMed1995

Reactivity and the fate of some composite bioimplants based on collagen in connective tissue.

Three composite materials based on collagen gel prepared with ISC40 and supplemented with the tripeptide glycine-histidine-lysine (GHK) mixed with bioglass (BAS O), pure hydroxyapatite (grain: 0.5-1.0 microns and 13-23 microns) and shredded beef bone were tested in the laboratory rat and guinea-pig. In the course of 49 d, no signs of infectious inflammation or incompatibility were observed around subcutaneously installed bioimplants. Particles of glass and hydroxyapatite became subject to phagocytosis. Bone fragments were completely resorbed, and no signs of osteogenic activity were detected in the neighbourhood.

Amino Acid Sequence↗

PubMed1995

[Tracheal replacement with a swine prosthesis].

In 12 experimental operations the authors tested the biocompatibility of a xenologous trachea from a pig which was used to replace a 5 cm defect of the trachea in a dog. After special preparation eliminating the antigenicity of the pig trachea the thus prepared graft was sutured into the thoracic portion of the dog trachea. The experiment could not be evaluated in two instances because the dog died on the operating table. In the remaining ten cases it was found that all anastomoses healed perfectly. The fibrous tissues of the tunica propria of the graft was replaced by granulation tissue. Across the anastomoses newly formed capillaries penetrated into the trachea where they caused chondrolysis. This led to a breakdown of the central portion of the prosthesis and stenosis in the airways with terminal respiratory failure. The mucosa of the graft was at some sites covered by metaplastically altered epithelium. Even a reinforcing vascular prosthesis did not prevent the breakdown of the wall of the xenologous graft. An asset for future work is the finding of a well healed suture between the graft and the trachea and evidence that newly formed blood vessels penetrated into the prosthesis.

Animals↗

PubMed1994

[A tracheal prosthesis made from P(AEMA)--a further step toward tracheal replacement].

In animal experiments (5 dogs) the authors tested a material for the construction of tracheal prostheses so far not used in other countries. P(AEMA), the polymer 2-acetoxy-ethylmethacrylate is well tolerated, it did not produce a rejection reaction. The inner wall of the prosthesis was throughout the experiment patent, smooth and secretion did not adhere to it. Macroscopic examination did not reveal cumulation of mucus and signs of infection. The self-cleansing capacity was not impaired and the dog was able to expectorate mucus over a 5 cm length of the prosthesis. The solid ends of the prosthesis, however, caused mechanical irritation of the site of anastomosis and after cca 4 weeks of the experiment granulation tissue began to form. The experiments were terminated on account of complete occlusion of the lumen of the airways by granulation tissue 4-6 weeks after operation. The authors' efforts to design a suitable tracheal prosthesis led to a change of strategy of subsequent research. They started experiments with a heterologous portion of the pig trachea devoid of antigenicity; this will be the subject of a subsequent paper.

Animals↗

PubMed1994

[Replacement of the trachea with a prosthesis--an unsolvable problem?].

Reconstruction of the trachea by means of a segmental prosthesis is a complicated problem, which has not been completely resolved so far. The authors present a brief historical review of attempts to bridge the gap by different types of prostheses Evon Neville's silicone prostheses are not well tolerated on a long-term basis and its is thus important to look for other materials for the manufacture of an "ideal" tracheal prosthesis. (ur synthetic prosthesis made from poly/ARMA/is very well tolerated, similarly as silicone prostheses. Despite this the authors produced in 1993 a new type of prosthesis, based on antigenicity-deprived heterologous pig tissue. Trials with this prosthesis will be evaluated in a subsequent paper.

Humans↗

PubMed1990

Elastogenesis in the wall of the human thoracic aorta.

The results of this study dealing with the human thoracic foetal aorta testify that even in the middle of the fifth month of development the internal elastic membrane is not yet completely continuous. Furthermore they show that elastogenesis in the tunica media of the human thoracic aorta does not begin directly below the internal elastic membrane, as it does in the foetal aorta of the laboratory rat, but, as it can be seen in our material, somewhat deeper in the developing tunica media. A thin layer of less differentiated tunica media cells persists for a long time in the vicinity of the internal elastic membrane. In the middle of the fifth month, the fusing elastic membrane segments in the tunica media still consist of very immature elastic tissue with a large proportion of the microfibrillar component. The collagen fibrils in the intercellular spaces in the whole depth of the wall of the developing aorta do not become a part of the elastic membranes. Their bundles merely accompany all the elastic membranes in the wall of the thoracic aorta, including the internal elastic membrane.

Aorta, Thoracic↗

PubMed1986