On age-related changes of cell membrane permeability in human buccal epithelium cells.

An original method for the determination of cell membrane permeability has been developed. Human buccal epithelium cells were treated with Indigo Carmine and the percentage of stained cells was determined. Employing this method, the age-related differences in properties of plasma membrane in cells of human buccal epithelium were demonstrated.

Phase and structural changes in hydroxyapatite coatings under heat treatment.

Hydroxyapatite (HA) crystallites of smaller size than those formed during the spraying process are found in HA coatings on titanium as a result of the crystallization of the amorphous phase (approximately 630 degrees C) when the coatings are vacuum-heat-treated in the temperature interval 100-1000 degrees C. As the annealing temperature increases within the 630-1000 degrees C range, the size of the crystallites increases, and at 1000 degrees C reaches the size of those formed during the process of spraying. At the same time, at 800 degrees C and above, HA transforms into other calcium phosphate phases (alpha-tricalcium phosphate, beta-tricalcium phosphate, tetracalcium monoxide diphosphate).

Periodic crystallization effect in the surface layers of coatings during plasma spraying of hydroxyapatite.

A new effect of the amorphous component of periodic crystallization in the surface layers of coatings during hydroxyapatite (HA) plasma spraying is revealed. The effect is caused by significant temperature increases of surface layers due to plasma heating in the process of coating. Under prevalent spraying conditions, the crystallite sizes of the crystallite phase are considerably less than those in dense HA.

Hypotonic fragility of outer membrane and activation of external pathway of NADH oxidation in rat liver mitochondria are increased with age.

Great importance is attached to structural and functional deterioration of mitochondria as a reason for ageing of an organism; the attention of many scientists has been concentrated on such questions as age changes in the system of oxidative phosphorylation, damage of mitochondrial DNA by free radicals generated in the respiratory chain and inclusion of some fragments of mitochondrial DNA into the nuclear genome. Mitochondrial high amplitude swelling in a cell under some extreme conditions can possibly play a very important role in mechanisms of deterioration of energy transformation function, in activation of lipid peroxidation and mitochondrial DNA damage as a result of outer membrane disruption and release of enzymes from the intermembrane space (e.g.

Amorphous phase and morphological structure of hydroxyapatite plasma coatings.

It is shown that under standard conditions of plasma spraying hydroxyapatite powder reaches the substrate in the form of molten drops. On striking the surface, the molten drop splatters, cools rapidly and solidifies. Consequently, a pancake particle surrounded by tiny spherical or differently shaped particles is formed on the substrate.

Decrease of phosphorylating oxidation and increase of heat producing NADH oxidation in rat liver mitochondria during life-span prolongation of rats by calorie-restricted diet.

The influence of calorie-restricted diet, initiated at weaning, on some of the oxidative processes in liver homogenates and isolated mitochondria of 2-, 3-, 4-, 24-, 35- and 45-month-old male Wistar rats was studied in comparison with control ad libitum-fed 1-2 day-old rats and 0.5-, 1-, 2-, 3-, 4- and 24-month-old rats. It was shown that a calorie-restricted diet (at 37% of the ad libitum calorific level) did not change the rate of succinate oxidation coupled with oxidative phosphorylation in homogenates, but resulted in a decrease of succinate, glutamate plus malate and beta-hydroxybutyrate oxidation and cytochrome c-oxidase activity in isolated mitochondria without any uncoupling of oxidative phosphorylation or change in cytochrome content in the mitochondria.

The effect of tryptophan on the phenobarbital-mediated induction of cytochrome P-450 in rat liver. The role of tryptophan 2,3-dioxygenase.

The effect of intraperitoneal administration of phenobarbital (80 mg kg-1 body weight) and tryptophan (200 mg kg-1 body weight), separately or in combination, on the microsomal content of cytochrome P-450 and the activity of tryptophan 2,3-dioxygenase (EC 1.13.11.

The effect of inhibitors of transcription and translation on basal and haem-induced tryptophan-2,3-dioxygenase activity in the rat liver.

The effect of actinomycin D and cycloheximide on basal tryptophan-2,3-dioxygenase (EC 1.13.11.