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Biomedical subjects

I Zs-Nagy

Publications and source records attributed to I Zs-Nagy.

At least 55 records · Page 3Linked to original sources
PubMed1979

Effects of centrophenoxine on the monovalent electrolyte contents of the large brain cortical cells of old rats.

The effect of centrophenixine has been studied on the monovalent electrolyte contents of the brain cortical cells of old female Wistar rats by means of energy dispersive x-ray microanalysis. The drug was administered in form of an intraperitoneal injection of 100 mg/kg body weight for 20 days. The treatment decreased the potassium content in both the nucleus and cytoplasm in terms of dry mass fraction, whereas the sodium concentration remained unchanged. The Na+/K+ ration increased significantly in both cell compartments. The chloride content of the nuclei decreased slightly. If one supposes just 1--2% rehydration of the old cytoplasm, the decrease of the total ionic strength may be of considerable extent, it may even reach the values obtained in young adult animals. The results are interpreted in terms of a recently developed 'membrane hypothesis' of aging.

Aging↗
PubMed1978

In vivo stimulation of nerve cells by phytohemagglutinin. I. Alterations of some cytological aging parameters in rat brain cells.

Phytohemagglutinin P (PHA-P) was administered in form of intralumbar injection to old (24-27 months) female Wistar rats. PHA-P has an inductive effect also on the nerve cells. The thermal denaturation characteristics of the DNA in situ as well as the numerical density of perichromatin granules being connected to the extranucleolar RNA synthesis returned practically to the young levels in the large brain cortical cells and in the cerebellar granular cells 20 h after the injection. The reversal of these aging phenomena was accompanied by a significant decrease of intranuclear and intracytoplasmic K+ content measured by X-ray microanalysis in the dry mass, whereas Na+ and Cl- remained unchanged. If PHA-P causes also some (1-2%) rehydration of the old neurons, the total ionic strength in the cell due to the monovalents may even reach the young level. The possible regulatory role of the ionic strength and the Na+/K+ ratio in the chromatin function is discussed on the basis of experimental data. It is the first time that the reversibility of some cytological aging parameters has been demonstrated in vivo.

Animals↗
PubMed1977

Alterations in the numerical density of perichromatin granules in different tissues during ageing and cell differentiation.

Perichromatin granules (PG) were counted on electron micrographs of different tissues taken from young and old female Wistar rats as well as in the basal and spinous layers of adult human epidermis. A significant age-dependent decrease was observed in the following cell types: large brain cortical cells, cerebellar granular cells, hepatocytes, parotid gland cells. No significant decrease was found in the heart muscle nuclei and in the erythroblasts of identical maturation level. The number of PG decreased during the erythroblast maturation almost to zero, and increased in the cells of spinous layer of human epidermis as compared to the basal cells. There is a very wide variation in the number of PG per nucleus between the different tissues. The correlation between the transcriptional activity, the protein synthesis, ageing and cell differentiation is discussed.

Adult↗
PubMed1977

Age-dependent increase of intranuclear monovalent electrolytes as revealed by quantitative energy dispersive x-ray microanalysis.

The concentration of univalent electrolytes in the cell nucleus and cytoplasm of the big neurons of the brain and in hepatocytes was established in young, mature and old rats by means of microanalysis with X-rays. It was demonstrated that the Na+ and Cl-- content increases with aging in both tissues, while K+ increases in the neurons but not in the nuclei of the hepatocytes, At the same time some ions in the cytoplasm increase, while others decrease or remain stable. If a possible loss of water during aging is taken into consideration the result is a considerable increase in ion concentration in the nucleus. This may be regarded as one of the principal reasons for the increased density which accompanies aging and possibly as one of the cause of the aging process.

Aging↗
PubMed1977

On the reversibility of some cytological ageing parameters of rat brain cells by phytohemagglutinin.

It has been shown that the thermal stability of DNA in the brain cortical cells increases with the age. At the same time, the number of perichromatin granules being connected in some way to the messenger RNA synthesis and transport of the interphase nuclei, decreases in the same cells. In vivo treatment of the old animals by mitogens like phytohemagglutinin induced a reversal of both ageing phenomena: the thermal stability of DNA returned almost completely to that of the young animals, whereas the number of perichromatin granules rised again to the young level.

Aging↗
PubMed1977

Age-dependent changes of the protein synthetic machinery of liver cell cytoplasm as revealed by electron microscopic morphometry.

Complete electron microscopic morphometric explorations of the liver were carry out in groups of 5 each young, adult and old female Wistar rats. In addition, livers were studied 1, 5, 10, 20 days after 2/3 hepatectomy in old rats. Characteristic age-dependent change: Decrease of the surface density of total endoplasmic reticulums between 1 and 12--27 months of age. After the partial hepatectomy the regenerated old liver "shows a certain" rejuvenation. The results suggest the validity of the theory of accumulation of somatic mutations during aging.

Age Factors↗
PubMed1977

Experimental gerontology and quantitative cytology: a new approach to cellular ageing.

The application of the followiny cytologic methods for gerontological basis research is discussed: 1. Quantitative cytomorphology including electron microscopic morphometry and its combination with cytochemical reactions. 2. Histochemical studies on cell components like DNA in situ by means of acridine orange microfluorimetry and thermal denaturation. 3. X-ray microanalysis for measuring the intranuclear electrolyte contents. The results obtained indicate the usefulness and the validity of a quantitative cytological approach to the cellular ageing.

Acridines↗