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Biomedical subjects

C Pieri

Publications and source records attributed to C Pieri.

At least 73 records · Page 4Linked to original sources
PubMed1987

The effect of chronic hydergine treatment on the plasticity of synaptic junctions in the dentate gyrus of aged rats.

The number of synapses (Nv), the surface density of contact zones (Sv) as well as the average size (S) of E-PTA stained synapses in the supragranular layer of the dentate gyrus from adult (12 months), old (30 month), and Hydergine-treated old (30 months) rats were measured by using quantitative morphometric techniques. In old animals, Nv and Sv were significantly reduced, whereas S was significantly increased as compared with the values in adult rats. Hydergine (Codergocrine mesylate) treatment of old animals (3 mg/Kg/day for 4 weeks) influenced these three parameters, differentially. The Sv in aged animals receiving Hydergine, relative to that in untreated old rats, was significantly increased; the number and size of synapses in the treated old rats were significantly higher and smaller, respectively, than that in old controls. We interpret the present findings to indicate a modulating effect of Hydergine on the morphological plasticity of synaptic junctions in the dentate gyrus of aged rats.

Aging↗
PubMed1986

Quantitative investigation of the morphological plasticity of synaptic junctions in rat dentate gyrus during aging.

The morphological plasticity of synaptic junctions was investigated by means of quantitative stereology in the dentate gyrus supragranular layer of young (3 months), adult (12 months) and old (30 months) female Fisher 344 rats. The numerical (Nv) and surface (Sv) density and the average surface area (S) of EPTA-stained synaptic junctions were calculated on 100 EM pictures per age group. We found that Nv significantly increased between the young and adult group and decreased in old animals when compared both to 3 and 12 months of age. Sv was unchanged in young and adult rats, whereas it underwent a significant reduction in the old group. The percentage distribution of S showed that at 3 months of age the majority of the synaptic population had an average size ranging between 0.12 and 0.20 micron 2, whereas during adulthood and aging there was a shift towards smaller and larger synaptic contacts, respectively. Taking into account Nv, Sv and S all together per age group, the present findings demonstrate that the morphological aspect of synaptic plasticity is markedly influenced by time and that during aging it undergoes a serious impairment. The possible involvement in memory and learning processes of these synaptic age-related morphological adaptations and the fact that the investigated junctions are supposed to be cholinergic is discussed.

Aging↗
PubMed1986

Vitamin E deficiency alters the in vivo Rb+ discrimination of rat brain cortical cells.

The in vivo Rb+ uptake and release of rat brain cortical cells of 11-months-old rats fed with a vitamin E deficient diet was investigated. The animals were treated with a daily dose of 30 mg RbCl/100 g body weight for 14 days. After discontinuation of the RbCl treatment the animals were killed at intervals of 2, 4, 9 and 15 days, respectively. The intracellular Rb+ and K+ contents were analyzed by energy dispersive X-ray microanalysis, whereas concentrations of these two ions were determined by atomic absorbtion spectrophotometry in the serum and cerebrospinal fluid. Vitamin E deficient rats accumulate more Rb+ than age-matched normally fed animals at any time taken into account. Rb+-discrimination ratios calculated on the basis of Rb+ and K+ contents of both, cortical cell cytoplasm and cerebrospinal fluid, are higher in vitamin E deficient rats than in the controls (+20%), which supports the view that the enhanced membrane lipid peroxidation induced by vitamin E deficiency impairs the passive membrane permeability for Rb+ (and K+).

Aging↗
PubMed1986

Age-related morphological rearrangements of synaptic junctions in the rat cerebellum and hippocampus.

A quantitative investigation has been carried out on the age-related morphological changes of the synaptic junctions in the cerebellar glomeruli and in the supragranular layer of the hippocampal dentate gyrus of young (3 months), adult (12 months) and old (28-30 months) rats. The numerical (Nv) and surface (Sv) density as well as the average length (L) of E-PTA stained synapses was calculated by means of morphometric methods. The results we obtained showed a similar trend in both these areas of the CNS. Nv significantly increased between young and adult rats and significantly decreased in the old group, when compared both to young and adult animals. Sv appeared to be unchanged comparing young and adult animals, whereas it was significantly reduced in the old group. L showed a decrease between 3 and 12 months of age and appeared to be markedly increased in the old animals when compared to adult values. From the present findings it can be inferred that number (Nv) and size (L) of the synapses are in a close inverse relationship which, through the organism's life span, aims to maintain the constancy of the surface contact area (Sv) among the dendritic network. By considering Nv, L and Sv altogether per age group, we were able to obtain a reliable measurement of the morphological aspect of synaptic plasticity through different periods of the life. With regard to aging we found that, despite the 'compensative synaptogenesis' brought about by the increased size (L) of the synaptic appositions, the reactive capacity of old nerve cells is seriously impaired.

Age Factors↗
PubMed1985

Amiloride inhibits the PHA-evoked mouse splenic lymphocyte proliferation.

The present study was aimed to ascertain whether Na+ influx can be involved in regulation of blastogenesis and proliferation of PHA stimulated mouse splenic lymphocytes. The cells were cultivated in the presence of different concentrations of amiloride, an inhibitor of passive Na+ influx, and cellular activation was monitored by 3H-thymidine incorporation and blast index determination. The drug was not toxic and inhibited cell growth in concentrations ranging from 1 X 10(-3) to 1 X 10(-5) mmol/ml. The results are in agreement with the hypothesis that Na influx is necessary for PHA evoked mouse splenic lymphocyte activation.

Amiloride↗
PubMed1985

Chronic dietary choline modulates synaptic plasticity in the cerebellar glomeruli of aging mice.

A morphometric investigation was carried out on ethanolic phosphotungstic acid (E-PTA) stained synaptic junctions in the cerebellar glomeruli of adult, old, old choline-deficient and old choline-supplemented mice. Numerical (Nv) and surface (Sv) density as well as average length (L) of the synapses were calculated on 100 pictures per group. A significant reduction of Nv and Sv, as well as an increase of L was found during aging. Choline deficient animals did not show any change as compared to old animals of the same age. In choline supplemented mice Nv and Sv were significantly increased and L significantly decreased, respectively, as compared to old control littermates. No difference was found between adult and choline supplemented mice. In the cerebellar glomeruli only a small fraction of fibers are cholinergic, therefore the present findings support the idea that dietary choline can influence systems other than cholinergic. The possible role of choline supplementation in the modulation of synaptic plasticity via the synthesis and/or turnover of neuronal membrane choline phospholipids, is discussed.

Animals↗
PubMed1985

A modulating effect of Hygergine on the synaptic plasticity of old rats.

The morphological plasticity of E-PTA stained synaptic junctions was investigated by means of quantitative morphometry in the dentate gyrus supra-granular layer of adult, old and old-Hydergine treated rats. Numerical (Nv) and surface (Sv) density as well as average size of the synapses (S) were the three parameters considered. During aging, Nv and Sv significantly decrease whereas S increases. Hydergine treatment to old rats resulted in a significant increase of Nv and Sv and a significant decrease of S. Present findings are interpreted as a modulating effect of Hydergine on the synaptic plasticity of old rats.

Aging↗
PubMed1984

Effect of chronic vitamin E deficiency on the synapses of cerebellar glomeruli in young rats.

A morphometric investigation has been carried out on the synaptic junctions in the cerebellar glomeruli of young-adult rats chronically deprived of vitamin E for 10 months and control animals of the same age. The following parameters were evaluated: the average length of the synapses (L), the numerical (NV) as well as the surface (SV) density of the synaptic contact zones. The results from these experimental groups were compared with data from young, adult and old rats. The results obtained show a significant decrease of the surface density of the synaptic contact zones in old and alpha-tocopherol deprived young-adult (11-month-old) rats as compared to younger and normally fed animals. This reduction of the synaptic contact area seems to be due to the marked decline in the number of synapses found in both cases. The average size (L) of the synaptic junctions, on the other hand, was increased in alpha-tocopherol deficient rats as compared to normally fed littermates. The significant reduction of the synaptic contact area in old and vitamin E deprived young rats supports the hypothesis that a common denominator may be responsible to explain this alteration. Because of the recognized protective role of alpha-tocopherol against free radical attacks on plasma membranes, the present findings support an involvement of membrane structural alterations in aging as well as in vitamin E deficiency.

Aging↗
PubMed1984

Amiloride, a diuretic with in vitro antimicrobial activity.

The effect of amiloride, an inhibitor of passive sodium influx in animal cells, was investigated on the in vitro bacterial growth. Amiloride blocked the growth of different bacterial strains at concentrations ranging from 25 to 1,300 micrograms/ml. While generally the block was bacteriostatic and bacteria, on amiloride removal, recovered their ability to growth, the drug showed a killing activity on hemolytic streptococci. Gram-positive bacteria revealed a greater susceptibility to amiloride than gram-negative ones. Although an hitherto unknown effect of amiloride cannot be excluded, from the known mechanism of action of amiloride on animal cells it might be suggested that sodium permeability plays a critical role on bacterial multiplication.

Amiloride↗
PubMed1984

Amiloride inhibition of triiodothyronine stimulated hepatocyte proliferation in vivo, and involvement of the intracellular Na+ content in mitotic regulation: an X-ray microanalytic study.

Energy dispersive X-ray microanalysis was carried out on the nuclei of hepatocytes stimulated to proliferate by the injection of a pharmacological dose of triiodothyronine (T3). The Na+ content displayed a continuous time-dependent increase in T3 stimulated animals. The Cl- concentration followed the same pattern as did the sodium, but its increase was lower. In contrast to Na+ and Cl- concentrations, the alteration in K+ content displayed a slight but statistically significant decrease at 8 h and 16 h from T3 injection and returned to the control levels by 22 h. The modifications of the Na+ and K+ content of the nuclei are reflected in their Na+:K+ molar ratios. A positive correlation was found between the increase of this parameter and the DNA synthesis rate of T3 stimulated hepatocytes. Amiloride was able to inhibit the stimulatory effect of the hormone, blocking the increase of both the intranuclear Na+:K+ ratio and of the DNA synthesis rate of hepatocytes. The findings are consistent with the hypothesis that a high Na+ content is associated with mitogenesis and, moreover, that an increased Na+ influx plays a causal role in regulating cell proliferation.

Amiloride↗
PubMed1983

In vitro block of murine L 1210 leukemia cell growth by amiloride, an inhibitor of passive Na+ influx.

The present study was aimed to decide whether Na+ influx can be involved in regulation of murine L 1210 leukemia cell growth. Cells were cultivated in the presence of different concentrations of amiloride and cellular growth was monitored by 3H-thymidine incorporation/10(5) cells. This drug inhibited cell growth in concentrations ranging from 1 X 10(-5) to 1 X 10(-3) mmol/ml. Even short time treatments with amiloride caused irreversible alterations: the cells, although survived, lost their ability to divide. The results support the hypothesis that Na+ influx is necessary for the duplication of tumor cells.

Amiloride↗
PubMed1983

X-ray microanalysis of monovalent electrolyte contents of quiescent, proliferating as well as tumor rat hepatocytes.

Energy-dispersive X-ray microanalysis was carried out on normal and regenerating liver as well as on 3924 A hepatoma cells. Specimens were quickly removed from the sacrificed animals, frozen in liquid isopentane, fractured still in the frozen state and freeze-dried under vacuum. The dried samples were examined in secondary electron image mode, and the X-ray spectra were recorded by means of an EDAX 707A system. Sodium and chlorine contents were higher both in nuclei and cytoplasms of regenerating and tumor hepatocytes than in normal liver. Moreover, hepatoma cells showed higher sodium and chlorine contents than did normal proliferating hepatocytes. Potassium contents did not show any differences among the experimental models. The increased sodium content and the resulting increased Na:K ratios of proliferating normal and tumor cells were not due to a generalized increase of these parameters in all the cells, but to the presence of new cell populations with high Na content and high Na:K ratios. Findings of present work are consistent with the hypothesis that high sodium content is associated with mitogenesis. Moreover, the much higher concentration of sodium in tumor cells as compared with normal proliferating hepatocytes supports the hypothesis that the concentration of this ion is related to oncogenesis of hepatocytes.

Animals↗
PubMed1982

Age-dependence of the stimulatory effect of triiodothyronine on the DNA synthesis of rat hepatocytes.

The effect of a single subcutaneous injection of triiodothyronine (T3) on DNA synthesis rate and liver growth was studied in young and old female Wistar rats. The hormonal treatment was effective in stimulating DNA synthesis, resulting in an increase of the specific liver volume as well as volume and numerical density of nuclei/100 g body wt. in young animals. In the old animals T3 injection induced a reduced and delayed synthesis of DNA, which did not affect the morphometric parameters of liver/100 g body wt.

Aging↗
PubMed1982

The effect of acute and chronic centrophenoxine treatment on the synaptic plasticity of old rats.

The cerebellar glomerulus was studied by electron microscopic morphometry in female Wistar rats. Age-dependent alterations have been revealed from 3 to 28 mth of age, and the effect of centrophenoxine (CPH) was analyzed in two different patterns of administration. First, 27-mth-old rats were treated daily for 6 wk (acute treatment), and second, 18-mth-old rats were treated 3 times per week for 5 months (chronic treatment). The dose was 100 mg CPH/kg body weight, injected intraperitoneally. The surface density (SV), the numerical density (NV) and the average length (L) of the synaptic junctions were calculated from data obtained on ethanol-phosphotungstic acid stained ultrathin sections. An age-dependent reduction of SV and NV of the synaptic contact zones was found, and the L increased in the oldest animals. CPH-treatment resulted in a marked increase of SV in both types of application, whereas the other two parameters behaved differently in the two groups. The chronic treatment resulted in a significant slowing down of the decrease of NV, whereas L remained invariate. On the contrary, the acute treatment increased L but did not alter significantly NV. The results and the differences between the treatment types are discussed in terms of synaptic plasticity and are interpreted as different manifestations of the same reactive synaptogenetic process.

Aging↗
PubMed1980

Electron-microscopic morphometric analysis of mouse liver. I. Experimental studies on the morphogenetic significance of the thymus in nude and normal mice.

Haired, nude, thymus-grafted nude and haired thymectomized Balb/c-nu mice 2 months of age were studied by electron-microscopic stereology. Each group consisted of 5 animals and a complete morphometric analysis was carried out on their livers. In the absence of the thymus there is a slowing down of the development of the whole organism. Among the liver parameters especially the nuclear ones displayed alterations. Namely, the volume of hepatocyte nuclei increased above the normal level and this phenomenon was reversed by thymus graft into the nude mice. The hepatocyte volume also increased significantly in the surgically thymectomized group, influencing all the morphometric parameters regarding mitochondria and endoplasmic reticulum, when measured per hepatocyte. On the basis of the results obtained, one can conclude that the thymus has a regulatory role in the development of hepatocyte morphology. The findings agree with the biochemical observations demonstrating non-immunological effects of the thymus on cellular development.

Animals↗