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Biomedical subjects

W Knöfler

Publications and source records attributed to W Knöfler.

At least 19 recordsLinked to original sources
PubMed1990

[The question of the transmissibility of the results of subcutaneous tests of biomaterials from animals to humans].

The histologic estimation of the subcutaneous connective-tissue reaction at implants forms an important part of the biocompatibility test. The connective-tissue capsulae around titanium implants in man, guinea-pig, and Wistar-rat were analysed by a special test system because of the question concerning the transmission of results of animal experiments on the man. The subsidence process of the thickness of the connective-tissue capsule and of the cell count per measuring fields were represented in dependence on the time. The findings showed the fundamental similar course of wound healing in man, guinea-pig, and Wistar-rat by the influence of an implant.

Animals↗
PubMed1989

[The use of tantalum wire as a suture material].

The qualification of tantalum wire as suture material was tested by means of physical and histological investigations. Starting-point were the physiochemical and biological attributes and its hitherto existing employment in the medicine. Indication and recommendations for handling the material were found out.

Animals↗
PubMed1989

[Stimulated osteogenesis in bone cysts].

This method deduces from classical therapeuticál principle of bone jaw cysts from Partsch (1892, 1910) and Schulte (1959, 1960, 1964) and has regard the modern results of biomaterial research. It is used mixing of anorganic and organic materials, which proportion is in accordance to normal bone tissue. In 39 till now operated cases of different bone defects we attained good clinical events. The first cases are controlled since two years.

Biocompatible Materials↗
PubMed1988

[Investigations on the tissue compatibility of silicon rubber materials using experimental animals].

The reaction of subcutaneous tissue in guinea-pigs at implants of six kinds of silicone rubber materials (VEB Chemiewerk Nünchritz) was investigated by semiquantitative and quantitative methods. These based on the "Programme to the Assessment of Subcutaneous Tissue Reactions at Implants" by Knöfler, Keller etc. The histocompatibility of the tested materials can be compared with that of titanium. One of the silicone rubbers differs from both the reference material and the other silicone rubber materials significantly and is assessed to be more suitable than the alloy Gisadent KCM 83 (chromium cobalt molybdenum alloy).

Animals↗
PubMed1986

[Procedure for the biological testing of substances in the guinea pig subcutaneous test. I. The results of an improved semiquantitative assessment of the histological criteria].

Different materials were implanted into the subcutaneous connective tissue of guinea pigs to evaluate biotolerance by means of the tissue response. The investigations were carried out with reference materials and newly developed implant materials in short-term studies and in case control studies. The semiquantitative valuation standards lead mostly only to informing statements in the sense of a compatibility degree. Alternative assertions are possible when comparing very different materials.

Animals↗
PubMed1986

[Procedure for the biological testing of substances in the guinea pig subcutaneous test. II. The results of mathematical evaluation and modelling of the morphometric data on the area of reaction].

The extent of the reaction area around implanted materials (connective tissue capsule) was measured by the electronic device system Densitron and was represented in its temporal dependence after implantation. A histocompatibility index (referring to titanium as reference material) was deduced from the course of the connective tissue adaptation (healing in process). Linear regression calculation shows that the healing in process can be described very well by means of a power function for the most of the investigated materials. A clear demarcation and classification of the tissue tolerance of the different materials was managed for the histocompatibility index and also by the obvious integral values of the experimentally found out and mathematically modelled subsidence curves of the connective tissue reaction (selected period: 90th to the 200th day after the implantation).

Animals↗
PubMed1986

[Procedure for the biological testing of substances in the guinea pig subcutaneous test. III. The results of the quantitative determination of the cell division pattern in the area of reaction].

The counting of the type of cells in the surroundings of implanted materials enables the estimation of specific material effects and improved the statement of the biologic testing methods. The explained method is described in the example of reference materials and is applied to different new materials for the estimation of their histocompatibility.

Animals↗
PubMed1985

[Biocompatibility of implants with and without fluorohydrocarbon glow polymer coating. 4. Recommendations for the histocompatibility (repair) index for the evaluation of various implant materials].

The measurement of the thickness of the fibrous capsula around implant materials to different titmes and the material dependent speed of the subsidence process of the tissue reaction were formed to an index. The derivation of the index is described by a course study with 4 materials about 5 periods. The determination of the index is represented simply mathematically and also delineating-geometrically. The index should be determined between 50 and 200 days, better between 90 and 150 days. Individual wound reactions superimpose the material effect before and the final state of the tissue reaction hinders the speed interpretation of the quickness of subsidence prgcess after this period.

Animals↗