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Biomedical subjects

E Scherini

Publications and source records attributed to E Scherini.

52 records · Page 3Linked to original sources
PubMed1981

Cytochemical study of chromatin changes in Purkinje cell population as markers of rat cerebellar histogenesis.

In the population of rat cerebellum Purkinje cells, Feulgen-DNA contents higher than 2c are present starting from the 9th to the 12th day of postnatal life. This stage of histogenesis corresponds to the time when other histological and cytochemical parameters suggest that important functional changes are taking place in the cerebellum. Hyperdiploid values (H2c) gradually increase during the subsequent histogenesis, involving also the physico-chemical state of chromatin. The key steps of histogenesis suggested by our investigations might be a starting point of reexamine the problem of tritiated thimidine incorporation, in order to demonstrate the possible synthesis of extra-DNA.

Aging↗
PubMed1981

Some parameters for a cell cycle cytotopochemical study.

With the Feulgen-Naphthol Yellow double reaction we dosed, simultaneously on a cell, [1] the DNA nuclear content (as Feulgen positive material), [2] the protein cell content and [3] the Feulgen chromatin area; the degree of condensation is expressed by the ratio [1]/[3]. The evolution of the lymphocytes culture at different times of PHA stimulation was in this way studied with the aim of defining the existence of cell subpopulations pertaining at different phases or subphases of the cycle.

Blood Proteins↗
PubMed1980

[Studies on eosinophilic Purkinje cells. Effects of protein maternal malnutrition of their occurrence during cerebellar histogenesis in the rat (author's transl)].

The cytoplasmic eosinophilia of the Purkinje cells appears in controls at 16 days whereas in the offspring of malnourished mothers (fed 8% protein diet) it occurs at 22 days. The adult per cent values are reached by controls at 22 days and by malnourished animals at 30 days. This finding makes it difficult to refer to the cytoplasmic eosinophilia merely as fixation artifact. The possible interpretations for the occurrence of this parameter are discussed.

Animals↗
PubMed1980

On chromatin availability to hydrolysis of the Feulgen reaction in Purkinje neuron population: microdensitometric and microfluorometric data.

The earlier finding that the chromatin organization of Purkinje neurons is not the same in the whole population is confirmed in this study. This was found to be independent of the type of Feulgen reaction hydrolysis kinetics, analytical method (microdensitometry or microfluorometry) and tissue preparation (sections, isolated cells, isolated nuclei). This heterogeneity, possibly linked to different functional stages, leads to Feulgen-DNA contents which, at optimal hydrolysis times, range from 2c to 4c values. The results obtained are discussed in relation to those in the literature.

Animals↗
PubMed1979

Feulgen-DNA content of the Purkinje neuron: "diploid" or "tetraploid"?

Microdensitometric measurements of the Feulgen-DNA content of the Purkinje cells and of the small granular cells (2c control) were carried out at lambda 550 nm and by the two wavelength method according to Fukuda et al., and were also corrected for the glare. We analysed sections of perfused cerebella and isolated cells of cerebellar cortex from adult rats. The Purkinje cells had a mean value of Feulgen-DNA content 30-45% higher than the 2c value, irrespective of the methods of preparation or measurement.

Animals↗
PubMedDate not supplied

Induction of karyological damage by bleomycin in polyploidizating rabbit hepatocytes.

The effects of the antitumor drug bleomycin on polyploidizating hepatocytes of immature rabbits were investigated by combining cytochemical (static microfluorometry) and morphological (fluorescence and electron microscopy) approaches. In addition to a decelerating effect of the drug on the cell kinetics, there were several types of karyological damage (micronuclei, internuclear chromatin bridges, mitotic chromosome bridges), thus demonstrating a clastogenic activity of bleomycin on the DNA, Moreover, anomalous nuclear and cytoplasmic divisions suggest interference of the drug with other cellular structures (mainly the microtubule network) responsible for the cell kinetics.

Animals↗
PubMedDate not supplied

MPTP-induced increase in c-Fos- and c-Jun-like immunoreactivity in the monkey cerebellum.

The transcription factors c-Fos and c-Jun have been described to be overexpressed following many pathological stimuli, but whether they are required for neurodegeneration or neuroprotection is still open. In the present report, we analyzed the role of c-Fos and c-Jun proteins in Purkinje cell degeneration caused by the neurotoxin MPTP (1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine) in the monkey cerebellum, and determined the neuroprotective effect of the antioxidant drug a-dihydroergocryptine (DHEC), whose prior and simultaneous administration reduced the MPTP-induced neuronal loss in the substantia nigra. Immunocytochemistry for c-Fos- and c-Jun-like proteins showed persistent increased staining in Purkinje cells of MPTP-treated monkeys. The staining was greatly reduced in animals receiving DHEC. Similar results were observed in white matter glial cells after immunoreaction for c-Fos. The results suggest that, at least as far as the cerebellum is concerned, the increase in c-Fos and c-Jun expression correlate with cell damage, rather than with preservation.

1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine↗
PubMedDate not supplied

Possible patterns of nuclear rotation in binucleate hepatocytes in vivo: static examination with fluorescence and electron microscopy.

To demonstrate nuclear rotation in the intact organism, we induced the formation in vivo of internuclear chromatin bridges in binucleate hepatocytes and examined their morphological arrangement in static conditions. Fixed isolated hepatocytes were observed by fluorescence microscopy and solid liver tissue by electron microscopy. The morphological patterns provided information about different modalities of nuclear rotation, related to equatorial (stationary nuclei), peripheral (nuclei rotating in opposite direction) or oblique (nuclei rotating in the same direction) dispositions of chromatin bridges. Moreover, data indicate that the entire nucleus can rotate. The independence of the bridge arrangements from the cell cycle phases (G1, S, G2) suggests that the nuclear rotation is probably not due to exchange of substances between the active chromatin and the cytoplasm.

Animals↗
PubMedDate not supplied

Inhibitory cerebellar circuits: GAD immunoreactivity in the frog cerebellum.

The presence of GABAergic structures in the frog cerebellum with simple nervous circuits was investigated with an immune serum raised against glutamic acid decarboxylase (GAD). GAD immunoreactivity is detectable in all the cerebellar layers. The most obvious difference in comparison with mammals is the scarcity of GAD-positive terminal boutons on Purkinje cells and this is consistent with neurophysiological data indicating that the inhibition on frog Purkinje cells is weaker than in mammals. However, there are numerous GAD synapses on cerebellar and vestibular nuclei. A large number of GAD immunoprecipitates are present in the molecular and granular layers, though their morphological organization is different from that in mammals. In the upper part of the molecular layer GAD immunoreactive cells and fibres form a plexus-like structure and in the internal granule layer immunoreactive varicosities are not arranged in the ring-like assemblies of mammals.

Animals↗
PubMedDate not supplied

The action of cisplatinum (cis-DDP) on the postnatal growth of the rat liver. Cytokinetics and ultrastructural studies.

The early and late effects of cis-DDP treatment on liver cell kinetics were analyzed after its intraperitoneal injection into 17-day old rats. Frequency of binucleate hepatocytes, cellular DNA content distribution, 3H-thymidine labelling and ultrastructure of the nuclei were analyzed. Two days after treatment, a block of mononucleate hepatocytes in the S phase and in the G2 phase was demonstrated by the increase of intermediate 2c-4c and 4c DNA values in the absence of changes in 3H-thymidine labelling; 8c binucleate cells, which are essential for the formation of tetraploid mononucleate cells, were not found. In cell nuclei, large areas of more condensed chromatin appeared, perhaps providing further evidence for a G2 block. Seven days after treatment, there was a tendency to catch up with the normal situation, as shown by the unblocking of the S phase in mononucleate cells indicated by both cytophotometry and autoradiography. The presence of 8c binucleate cells and 4c-8c mononucleate cells indicates that 4c mononucleate hepatocytes are either diploid cells in the G2 phase or true tetraploid G1 cells. The decrease in the heterochromatin areas and the appearance of hypertrophic nucleoli demonstrate an increase in the metabolic activity of the nuclei. Thirty six days after treatment, the incidence of different DNA hepatocyte classes and the 3H-thymidine labelling were already similar in control and in treated rats.

Aging↗