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C Pieri

Publications and source records attributed to C Pieri.

At least 91 records · Page 5Linked to original sources
PubMed1980

Electron-microscopic morphometric analysis of mouse liver. II. Effect of ageing and thymus transplantation in old animals.

The influence of age and thymus on liver cells has been investigated by performing a complete morphometric analysis. The age-dependence was tested in three groups of mice aged 2, 12, and 24 months, while the action of the thymus was studied on 24-month-old mice grafted with neonatal thymus 30 days before the analysis was performed. Among the investigated parameters, the most considerable changes were found in the mean nuclear volume, which displayed a significant increase during ageing. The thymus was capable of reversing such an age-dependent increase when grafted into old animals. The volume of single hepatocytes also displayed an age-dependent increase which was not corrected by thymus grafting. The data presented suggest that the thymus influences the mitotic activity of the hepatocytes and further support the hypothesis that the thymus also plays an important role in non-immunological processes of ageing.

Aging↗
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 relationship between the perichromatin granules and cellular ageing as well as cell differentiation.

Current hypotheses ascribe the role of pre-RNA storage or transport structures to the perichromatin granules. Their numerical density is directly related to the transcription activity of the nucleus. The perichromatin granules (P.K.) can be demonstrated in ultrathin sections with the stain used by Bernhard (1969) for ribonucleo-proteins. We have established the numerical density per unit of area in nuclear cross-sections of cells in young rats (1-2 months), old rats (26-29 months) and in relation to various cell function types. Cell aging causes a reduction in the numerical density of perichomatin granules in the big neurons of the cerebral cortex, the cerebellar granulocytes, the hepatocytes and the parotid cells. No age-related changes were found in the myocardial cells and erythroblasts of the same maturity. However, at the end of maturation, the number of perichromatin granules both in young and old erythroblasts was nil. (1) There is a quantitative reduction of perichromatin granules primarily in postmitotic and relatively postmitotic cells; (2) cell types showing no age-related reduction in perichromatin granules maintain high synthetic activity throughout their life; (3) the results confirm that relationships exist between numerical density of the perichromatin granules and cell activity; (4) the big fluctuations in the numbers of perichromatin granules in various cell types are probably connected with cell function.

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↗
PubMedDate not supplied

Morphometric studies on synapses of the cerebellar glomerulus: the effect of centrophenoxine treatment in old rats.

Young, adult and old female Wistar rats (3, 18 and 28 months of age, respectively), were studied using electron-microscopic stereology. Synaptic parameters of the cerebellar glomerulus were calculated and compared with similar data obtained from old Wistar rats of the same breed treated with centrophenoxine (CPH; HelferginR, Promonta, Hamburg) in the form of intraperitoneal injections (100 mg/kg body weight) for 40 days. This treatment resulted in a sort of "rejuvenation" of synaptic structures. Namely, the surface density and the total length of synaptic contact zones were markedly reduced in the untreated old group, but in the treated animals these parameters returned to the values found in the young and adult animals. At the same time the numerical density of synapses remained unaltered in the treated group, while the average synaptic length displayed some further increase. The results are interpreted in terms of the age-dependent decrease in reactive synaptogenesis, suggesting that CPH stimulates the metabolism of the nervous elements persisting in old brain. The possible mechanism of CPH effect is also discussed.

Aging↗
PubMedDate not supplied

Food restriction in female Wistar rats. I. Survival characteristics, membrane microviscosity and proliferative response in lymphocytes.

The effect of food restriction on the survival characteristics, membrane microviscosity and proliferative response in lymphocytes of female Wistar undernourished rats has been evaluated. Diet restriction was applied starting from the age of 3.5 months by feeding the animals on an every-other-day schedule (EOD). Diet restricted animals showed an increase of both mean, median and maximal life span as compared to the rats fed ad libitum (AL). Analyzing the survival curves by a parametric model, it emerged that undernutrition increased the individual resistance to environmental insults. In particular, it could be speculated that the positive influence was more pronounced in individuals with the lowest physiological capacities. The membrane microviscosity of lymphocytes was lower in EOD animals as compared to the AL ones even if one assumes a decrease in body temperature of 1-2 degrees C in EOD groups. The improvement of membrane microviscosity due to diet restriction may in part explain the improvement of proliferative response of lymphocytes from EOD groups.

Journal Article↗
PubMedDate not supplied

Food restriction in female Wistar rats. II. Beta-adrenoceptor density in the cerebellum and in the splenic lymphocytes.

The effect of diet restriction, applied on an every-other-day schedule from 3.5 months of age on, has been investigated on the beta-adrenoceptor density in the cerebellum and in the splenic lymphocytes of old female Wistar rats. Comparing animals 6 months and 24 months old fed ad libitum, a 75% age-dependent reduction in specific binding of the agonist dihydroalprenolol was observed in cerebellar membrane preparations, while the beta-adrenoceptor density of lymphocytes remained unaltered. Diet restriction induced a partial recovery of the age-related decrease of this parameter in the cerebellum without affecting the receptor density of lymphocytes. Present results suggest that undernutrition delays the appearance of those alterations related to aging.

Journal Article↗