Expression of Aß42, τ-Protein, p16, p53 in Buccal Epithelium: Prospects for Use in the Diagnostics of Alzheimer's Disease and Rate of Aging.

The expression of Aß42, and τ-protein, and p16 and p53 proteins was analyzed in the buccal epithelium of elderly and senile patients with Alzheimer's disease. We revealed enhanced synthesis of Alzheimer's disease markers Aß42 (by 15-30 times) and τ-protein (by 5 times) in comparison with the corresponding values in people without neurodegenerative pathology of the same age groups. In addition, increased synthesis of proteins of cell aging and apoptosis p16 (by 6-10 times) and p53 (by 2-3 times) was observed in patients in comparison with age-matched persons without neuropathology. These data suggest that complex analysis of the expression of Aß42, τ-protein, p16, and p53 in the buccal epithelium is a promising method for in vivo diagnosis of Alzheimer's disease and assessment of the rate of aging during the development of this pathology.

A method of creation a cell monolayer based on organotypic culture for screening of physiologically active substances.

We developed a method of culturing and phenotyping of a monolayer of cells of the retinal tissue, thymus and spleen on the basis of organotypic culture. All characteristic types of neurons and fibroblasts were found in their microenvironment in the retinal cell monolayer. Lymphocytes, macrophages, and fibroblasts were verified in the monolayer of thymus and spleen cells. Histological staining, immunocytochemistry, and electron microscopy demonstrated the possibility of assessing the differentiation degree and functional activity of the cell monolayer. The developed technique preserves cell-cell interactions and a variety of cell types characteristic of the examined organ in the monolayer. This opens up new prospects for its application in basic research and in screening of different physiologically active substances.

Melatonin and colon carcinogenesis. II. Intestinal melatonin-containing cells and serum melatonin level in rats with 1,2-dimethylhydrazine-induced colon tumors.

Two-month-old outbred female LIO rats were injected weekly with a single dose of 1,2-dimethylhydrazine (DMH; 21 mg/kg of body weight) administered s.c. for 15 consecutive weeks. From the day of the 1st injection of the carcinogen the part of rats were given five days a week during the night time (from 18.00 h to 08.00 h) melatonin dissolved in tap water, 20 mg/l. The experiment was terminated in 6 months after the first injection of the carcinogen. The concentration of melatonin in the serum was estimated by radioimmunoassay in rats exposed to DMH alone or in intact control rats in the morning (between 10.00 and 11.00 hours) and night (between 24.00 and 01.00 hours) time. Number of melatonin-containing cells (M-cells) and their optical density were estimated by immunohistology in normal mucosa of glandular stomach, duodenum, ileum and descending colon of tumor-bearing animals from groups exposed to DMH or DMH+melatonin. It was shown that serum melatonin levels in rats with colon tumors was increased as compared with controls. However there was no diurnal rhythm of serum melatonin of colon tumor-bearing animals as compared to intact controls. The number of M-cells was decreased in all tissues studied in rats with DMH-induced colon tumors in comparison to corresponding controls: by 2.0 times in stomach, by 1.8 time in duodenum, by 1.3 times in ileum, and by 1.8 times in colon. In ileum and colon of rats treated with DMH+melatonin the number of M-cells was similar to control level whereas in stomach and duodenum this number was significantly higher than that in rats treated with DMH alone, but less than in corresponding controls. Relative content of melatonin in enterochromaffin cells of all parts of gastrointestinal tract evaluated as optical density of the cells and was decreased in rats exposed with DMH alone in comparison to the controls and was normalized and similar to the norm level in rats treated with DMH+melatonin. Thus, exogenous melatonin prevent a decrease in numbers of melatonin-containing cells as was observed in gastrointestinal tract (GIT) of rats exposed to DMH. This preventive action of melatonin correlated well with its anticarcinogenic effect.