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Biomedical subjects

K J Stiller

Publications and source records attributed to K J Stiller.

At least 37 records · Page 2Linked to original sources
PubMed1983

[Studies of the cell cycle of experimental animal tumors following X-ray treatment].

With the aim to contribute to optimized radiotherapy the proliferation kinetic parameters in experimental animal tumors were determined. As compared to non-radiated tumors, a single X-ray dose of 3 Gy accelerated the time course of the mitotic cycle which may be interpreted as a repair response. In contrary, following a single irradiation with 12 Gy the mitotic phases were delayed in their temporal course. Surprisingly, fractionated irradiations of these tumors yielded significantly less favorable results (no tumor regression, shorter rates of survival) in comparison with those after a single high X-ray dose. Obviously, this is due to a great share of hypoxic tumor cell areas in solid Ehrlich carcinomas which cannot irreversibly be impaired by low radiation doses.

Animals↗
PubMed1983

[Effect of the photometric resolution on the precision of microphotometric measurements].

From investigations on microautoradiographs of suitable biological structures, it is concluded, that for the determination of photometric quantities without loss of accuracy a photometric resolution of n = 10 intervals of optical density is sufficient. A low photometric resolution allows to represent the local distribution of substances more clear and the expense of analysis is reduced.

Animals↗
PubMed1983

[Experiences with the 14C-aminopyrine breath test in liver cirrhosis and under the effect of sodium diclofenac (Voltaren)].

The 14C-aminopyrine breath test is a simple procedure for the non-invasive determination of the microsomal function of the liver. After the oral administration of a tracer dose of 2 microCi (74 kBq) of 14C-aminopyrine the 14CO2 activity of the expired breath air is determined in hourly intervals. There is a close correlation between its decrease and the elimination of aminopyrine from the plasma. Both the elimination constant of 14CO2 (Kbreath) and the maximal specific 14CO2 activity are useful quantitative parameters of the test. They allow conclusions as to the hepatic demethylation capacity. Both parameters were significantly lower in 15 patients with liver cirrhosis than in 12 control patients. The non-steroidal anti-inflammatory drug diclofenacsodium (Voltaren) did not significantly influence the demethylation of 14C-aminopyrine in 5 patients with rheumatic diseases and in 2 healthy probands. Further experiences with the breath test are necessary, especially with respect to its suitability for prospective investigations.

Adult↗
PubMed1981

[Cell proliferation kinetics in the small intestine of rats with injured kidneys (author's transl)].

Cell proliferation studies were performed in the duodenum, jejunum and ileum of 10 rats 5 months after 5/6 nephrectomy. The control group consisted of 8 unoperated rats. The results showed no differences in the labeling index, in the localisation of the proliferation within the crypts of Lieberkühn and in the migration of labeled cells from the crypts to the top of the villi in both groups. These results may be explained by the small degree of renal insufficiency.

Animals↗
PubMed1979

Cell-mediated immunity to influenza virus antigen and mitogen in guinea pigs: measurement with a semimicro protein synthesis assay.

A rapid and precise method for the assay of cell-mediated immune response basing on protein synthesis stimulation of mitogen-activated guinea pig lymphocytes is modified in a way that enables the study of virus-immunological problems. When used as a micromethod it has the following advantages over conventional methods: short-term cell culture, need of low quantities of cells and rapid preparation of great numbers of samples for radioactivity measurements. In this study we report the results of comparative experiments on measuring lymphocyte stimulation after addition of PHA and stimulation of sensitized lymphocytes following contact with homologous influenza virus antigen in vitro. The most important reaction parameters are as follows: 5-6 . 10(5) spleen lymphocytes/microculture in microtiter plates, use of Eagles's MEM cell culture medium without leucine, supplemented with HEPES buffer and 10% autologous guinea pig serum; optimum lymphocyte stimulation by addition of 0.5 microliter PHA or 0.1-1.0 microgram virus protein/ml; immuno-stimulation by PHA can be measured in vitro already after 6 h and by influenzavirus antigen already after 24 h.

Animals↗
PubMed1978

On methods of silver grain counting in histoautoradiograms.

Visual silver grain counting in histoautoradiograms is a slow and tedious procedure. In this study different methods of automation of grain counting, possibilities of use as well as their advantages and disadvantages are critically compared. By means of autoradiograms of 3H-phenylalanine-labelled rat liver specimens the possibilities of automated image analyses are demonstrated. The use of these techniques enables rapid counting of silver grain densities over cell nuclei and cytoplasm.

Autoanalysis↗
PubMed1978

Killing of untreated target cells by nonimmunized rat macrophages in vitro. I. Studies on the type of effector cells and their capacity to destroy allogeneic target cells.

Spleen cells derived from unsensitized Wistar rats lysed untreated, allogeneic liver cells of high passages (93rd until 159th subculture) as well as allogeneic tumor cells in mixed cultures. On the other hand, rat liver cells between passages 42 and 56 and allogeneic or xenogeneic fibroblasts were not destroyed by rat spleen cells in vitro. The degree of target cell lysis was dependent on the incubation time and effector-target cell ratio. In the rat spleen, the macrophages were detected as effector cells. Rat peritoneal cells showed the same effects as rat spleen cells. Trypsin treatment caused no loss of cytotoxicity of rat macrophages. Thymocytes and blood lymphocytes of rats were not cytotoxic against allogeneic or xenogeneic target cells. The macrophages apparently destroyed target cells by a nonphagocytic form of cell contact. Unstimulated spleen cells of guinea pigs, Syrian hamsters, CBA mice and rabbits were not capable to destroy target cells in allogeneic and xenogeneic systems.

Animals↗
PubMed1977

[Proliferation kinetic examinations on an experimental renal tumour with high portion of hypoxic tumour cells (author's transl)].

By autoradiographic examination by means of pulse labelling with 3H-thymidine cell cycle times were determined in solid Ehrlich carcinomas (early carcinomas) in order to obtain comparative values for irradiated tumours. The subcells of the initially labelled cells near the capillaries were found to distribute themselves in the course of 48 h over the whole tumour and to emigrate to hypoxic tumour areas.

Animals↗
PubMed1975

The proliferative activity of the adrenal cortex as influenced by carcinogenic and noncarcinogenic substances.

A single oral toxic dose of carcinogens (N-nitrosomorpholine, aflatoxin B1, N--methyl-N-nitrosourea, urethan) causes a significant increase of the mitotic rate in the adrenal cortex 48 hours after application. Both, the control animals (water via stomach tube) and the animals treated with acetylsalicylic acid, arsenic, phenol and actinomycin D do not produce this effect. These findings confirm our previous results obtained by administration of acetylaminofluorene, diethylnitrosamine, dimethylnitrosamine and trinitroso-trimethylen-triamine. It is possible that the increased mitotic activity of the adrenal cortex is correlated with the substances applied.

Adrenal Cortex↗
PubMed1975

The budgerigar (Melopsittacus undulatus) as endocrinological test model. Thyroxine transport in blood.

By comparing in-vivo and in-vitro investigations the transport protein of thyroxine in the budgerigar (Melopsittacus undulatus) was determined. Electrophoretic and auto-radiographic methods were applied. Both investigations show the alpha-globulin to be a thyroxine-binding protein. The contradictions to other investigators are discussed. The experimental animal as an endocrinological model of the thyroid for questions of human medicine is recommended.

Animals↗