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Biomedical subjects

M Stol

Publications and source records attributed to M Stol.

16 recordsLinked to original sources
PubMed1992

Implantation of p(HEMA)-collagen composite into bone.

The replacement of bone defects is very important in clinical practice. This study compares biological properties of poly(2-hydroxyethyl methacrylate)-collagen composite with those exhibited by pure p(HEMA), an insoluble fraction of calf skin collagen (ISC-40) and demineralized bone matrix after implantation into pig or dog femurs. The levels of biodegradation or destruction of implants and healing of bone defects were studied using X-ray photography, histology and enzyme histochemistry. The results indicated a significant effect of collagen on biological destruction of the p(HEMA)-composite implants; even a minute amount of collagen influences this process dramatically. A stimulatory action of collagen on new bone formation may be of importance in bone defect healing.

Animals↗
PubMed1992

Electrostatic interaction influences cell adhesion?

The effect of electrostatic forces on the adhesion of LEP-19 diploid embryonal fibroblasts, Hep-2 laryngeal carcinoma cells, Raji lymphoblastoma cells and Sp 2/0 myeloma cells was examined in vitro. Adhesivity of all tested cell lines was higher on the cationized glass than on untreated or anionized glass. The negatively charged sialic acids on the cell surface play a role in cell adhesion. The participation of electrostatic interaction is independent of the energy metabolism in serum-free conditions.

Anions↗
PubMed1991

Structural alterations of p(HEMA)--collagen implants.

Samples of linear (additionally crosslinked) p(HEMA) with different amounts of fibrillar collagen were implanted into the popliteal region of rats. After 3 month, the implanted materials were harvested and examined by SEM. The implants underwent marked structural or morphological changes. While the fibrillar collagen was readily resorbed by invading cells, the synthetic constituent persisted to biodegradation. The p(HEMA) residues were shaped into spherical particles, approx. 1-15 microns in diameter. The possible fate of these microparticles in the host organism is discussed.

Animals↗
PubMed1990

[The effect of the monomer HEMA (2-hydroxyethylmethacrylate) on cells cultured in vitro].

Techniques of dynamical observation of biotolerance as well as percentual mitotic determination have been applied to study the cytotolerance of HEMA monomer on the human in vitro cells. On these conditions, such a monomer was stated to show the complete cytotolerance concentrated as 1:1000, almost complete cytotolerance when diluted as 1:500, and the expressed toxicity when concentrated as 1:100, that is in the concentration which is tolerated well on implantation animal experiments. Of more sensitivity is therefore the test which uses the in vitro cultivated cells as an experimental object.

Cells, Cultured↗
PubMed1990

Comparison of the influence of gelatine and collagen substrates on growth of chondrocytes.

The effect of culture substrates on adhesion and growth of chondrocytes and the influence of varying amounts of foetal calf serum on cell proliferation are compared. Skin and cartilage gelatines and type II collagen were used as substrates. The cells used in the experiments were the primary cultures of chondrocytes, frozen primary cultures of chondrocytes and chondrocytes after the 1st subculture. Cartilage gelatine had a more marked influence on cell proliferation than skin gelatine, especially in primary cultures. The differences were off in cells after the 1st subculture. Differences in the number of cells are evident also after decreasing the serum concentration in culture medium.

Animals↗
PubMed1989

[Collagen as a biomaterial].

The authors discuss the characteristics of different types of collagen, their incidence, structure, chemical composition and physical properties with regard to their use as biomaterial. They also mention the antigenicity, effect on platelet aggregation, cytodifferentiation and cellular proliferation. The authors discuss different biomedical applications of collagen and methods of its sterilization.

Biocompatible Materials↗
PubMed1988

Irritation effects of residual products derived from p(HEMA) gels. II. Compounds extracted from hydrogels.

Samples of poly(2-hydroxyethyl methacrylate) p(HEMA) hydrogels were prepared using three different polymerization initiators. The gels were washed in water under standard conditions. The extracts were then examined for intradermal irritation in rats using a radioactive indicator (113mIn). The irritation effects were dependent on the concentrations of the irritating substances and also on the gel type. Solid discs made of the gels, washed to varying degrees of purity, were also implanted into rats. Tissue irritation, as well as some other biological responses, were followed in situ using the radioindicator and common histological techniques. The irritation effects were very mild (even with the unextracted gel material). A possible explanation for the events taking place at the site of implantation is presented.

Animals↗
PubMed1988

Irritation effects of residual products derived from poly(2-hydroxyethyl methacrylate) gels. I. Testing of some model compounds.

2-Hydroxyethyl methacrylate (HEMA) monomer and sodium benzoate, diluted with saline in the range 0-20%, were tested for intradermal irritation in rats. Radioactive indicator (113mIn) was used to quantify this biological response. At low concentrations (up to 1%) only a little irritation was recorded, while at higher levels (5% or more) a significant adverse reaction developed. The degree of irritation was dose dependent. In the concentration range 0-10%, the response was exponential. Model decomposition products derived from three different polymerization initiators were also tested. How the results obtained with the model irritants relate to real polymerization systems is discussed.

Animals↗
PubMed1987

Calcification of poly(2-hydroxyethyl methacrylate)-collagen composites implanted in rats.

Samples of the polyHEMA-collagen composites with varying collagen content have been implanted into the popliteal region of rats. Three, six and twelve months after the implantation, calcification of the implanted material was determined using a radioactive indicator. At the same time, the implants and surrounding tissue were examined histologically. The degree of calcification of the implants was dependent on the collagen content; it was more pronounced with a higher amount of collagen. The composites with 30% (w/w) or more collagen were biodegraded during the long-term implantation. It is suggested that the composites containing less than 20% (w/w) of fibrillar collagen are used for biomedical applications and that those with a higher collagen content for the in vitro studies.

Animals↗
PubMed1985

Poly(2-hydroxyethyl methacrylate)--collagen composites which promote muscle cell differentiation in vitro.

A new simple method has been developed which allows the mixing of poly(2-hydroxyethyl methacrylate)--polyHEMA--and fibrillar collagen in any desired ratio. PolyHEMA alone was shown to be an unsuitable cultivation substrate for primary cultures of chicken embryonic skeletal muscle cells. Composites containing polyHEMA and 50% (w/w) or more collagen supported myogenesis. Such layers, firmly adhered to the bottom of plastic Petri dishes, were mechanically stable and biologically active, thus favourably combining properties of both the original materials. It is suggested that polyHEMA-collagen composite layers may be used for cultivation of differentiating cells in vitro.

Animals↗
PubMedDate not supplied

The removal of residuals and oligomers from poly(2-hydroxyethylmethacrylate).

Poly(2-hydroxyethyl methacrylate) gels obtained by the cross-linking polymerization using four different free-radical initiators were washed with water. Chromatographically, the eluate appeared to be a mixture of low-molecular-weight compounds and of a small amount of the high-molecular-weight component. The UV and IR absorption spectra of compounds present in the eluate were compared with those of model compounds that were assumed to exist in the gel as impurities after the polymerization (monomers and oligomers of hydroxyethyl methacrylate, decomposition products of initiators). Time dependences of the removal of impurities from the gels by washing were measured. Most of the impurities were washed out within a few hours. In addition to the assumed impurities, the eluate was found to contain an unidentified compound that was still washed out after several months. Intracutaneous applications of this compound did not produce local irritation of the tested tissue.

Animals↗