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Biomedical subjects

K Ostrowski

Publications and source records attributed to K Ostrowski.

At least 109 records · Page 6Linked to original sources
PubMed1980

Evaluation of the amount of crystallinity of bone mineral in the course of the aging process in man.

The analysis of per cent osteoid tissue, ash content and crystallinity of bone mineral of 67 patients 20--90 years of age, who died suddenly because of various reasons, was performed. Electron spin resonance spectrometry was used for measuring crystallinity. One-way analysis of variation of the results grouped according to sex and age showed no significant differences what concerns the ash content and crystallinity. Percentage of osteoid tissue was higher in the older groups of patients. No differences were found between males and females in the corresponding age groups. The possible mechanism responsible for the slightly higher crystallinity of bone mineral observed in the oldest group is discussed.

Adult↗
PubMed1979

Further investigations on possible correlation between agglutinability and osteoinductive properties of established cell lines.

Various cell lines, including SV40 virus-transformed human and mouse fibroblasts, established fibroblastic and epithelial cell lines, as well as their hybrids were tested for osteoinductive properties versus presence of Concanavalin A receptors. No correlation was found between the presence of these receptors and osteoinductive properties of cells. So far, however, no osteoinductive cell line was found without Concanavalin A receptors. Thus, the significance of surface properties of cells in transmission of osteoinductive signal(s) remains an open question. None of the fibroblastic lines exhibits osteoinductive potential, in contrast to the HT-40 and WISH epithelial lines.

Animals↗
PubMed1977

High-speed autoradiography of 3H-thymidine-labelled nuclei.

High-speed autoradiography with stripping film of 3H-thymidine-labelled cells was tested. The tests involved: (a) various times of immersion of emulsion-covered cell preparations in the mixture of dioxane-PPO-POPOP, at 20 degrees C, (b) exposure of cell preparations and blanks for various times at either -70 degrees C or +20 degrees C, with different humidity levels. Autoradiographs of good quality could be produced by 2-min immersion in the scintillator, exposure time greater than or equal to 1 h at either temperature and relative humidity 20--30%. A linear relationship between autoradiographic efficiency and exposure time of 1--7 h was found at either temperature, although the efficiency of autoradiographs exposed at -70 degrees C was by approximately 30% higher than that of autoradiographs exposed at +20 degrees C. Background values of autoradiographs dried with a fan and exposed for 1/4--7 h at either -70 degrees C or +20 degrees C were 0.6--0.8 grain/100 micron2. Theoretical calculations and experimental data showed that high-speed autoradiographs are 30--50 times more efficient as compared with conventional stripping film autoradiographs, thus allowing a shortening of the respective exposure time. Theoretical aspects of efficiency and resolution of high-speed autoradiography are considered.

Autoradiography↗
PubMed1977

Initial studies on the crystallinity of the mineral fraction and ash content of isolated human and bovine osteons differing in their degree of calcification.

Several groups containing 10--15 isolated osteons differing in their degree of maturity were analysed. Samples were isolated from undecalcified human and bovine bone sections. The crystallinity coefficient, defined as the ratio of the number of radiation-induced paramagnetic defects in the crystalline lattice of hydroxyapatite to the total ash content, was calculated. The results were compared with measurements performed on fragments of total cortical bone, primary periosteal bone, and inner circumferential lamellar bone. The results show a higher crystallinity of fully calcified osteons as compared with that found at the initial stage of calcification. No differences in the ash content were observed between human osteons, from different stages of calcification evaluated morphologically and by X-ray absorption. These differences were evident when bovine osteons differing in their stage of calcification were compared. Human fully calcified osteons contain 60% ash and their crystallinity coefficient is 52.1. Human osteons at the initial stage of calcification contain 57% ash and their crystallinity coefficient is 40.6. The same parameters for fully calcified bovine osteons and for bovine osteons at the initial stage of calcification are 59% ash, 62.6 crystallinity coefficient and 46% ash, 43.0 crystallinity coefficient, respectively.

Adult↗
PubMed1975

Heterotopic chondrogenesis and osteogenesis induced by transformed cells: use of nude mice as a model system.

A subline of HeLa cells was shown to induce cartilage and bone formation in congenitally athymic (nude) mice when injected intramuscularly. The chondrogenesis and osteogenesis observed was similar to that found when other inducing epithelia are injected intramuscularly into cortisone-treated mice. A tumorigenic SV40 T antigen-positive human-mouse somatic cell hybrid with human chromosomes C7 and C6 did not induce cartilage or bone formation under similar conditions. The nude mouse may thus provide a system in which to investigate experimental host-cell differentiation without the complications of immunosuppression.

Animals↗