PubMed Health⌕ Search

Biomedical subjects

G Bernocchi

Publications and source records attributed to G Bernocchi.

At least 55 records · Page 3Linked to original sources
PubMed1985

Growth and polyploidization of the liver of early postnatal rats treated with bleomycin.

Bleomycin was administered to 6- and 10-day-old rats and its effects were examined after a two-week survival period. Decreases in body weight and some phenotype abnormalities occurred in both age groups. Decreased relative liver weight (g/g b.w.) was observed only in animals injected on PD 10. DNA microdensitometry and microfluorometry (Feulgen reaction and Hoechst 33342 staining) revealed an increase in the frequency of intermediate DNA values in animals injected on PD6 and killed on PD20. In older animals, i.e. in rats injected on PD10 and killed on PD25, increases in 4c mononucleate and 8c binucleate cells and also a reduction of the relative number of binucleate cells appeared, as compared with age-matched controls. In both age groups, karyological abnormalities, including micronucleate cells and imbalanced DNA content in binucleate cells, were observed.

Aging↗
PubMed1985

On the heterogeneity of Purkinje neurons in vertebrates. Cytochemical and morphological studies of chromatin during eel (Anguilla anguilla L.) life cycle.

The relationship between the heterogeneity of Purkinje cell chromatin and the functional involvement of cerebellum has been analyzed comparing two stages of eel life cycle (yellow eel and silver eel) which are characterized by a different degree of swimming activity. The DNA content and the chromatin condensation have been studied by means of microdensitometry (Feulgen-DNA, Feulgen-DNA/area), microfluorometry (DNA after intercalation with Propidium Iodide at low and high concentration) and electron microscopy. In the transition from the yellow eel to the silver eel, the Purkinje cell heterogeneity undergoes variations. In the silver eel, which shows a higher swimming activity, high Feulgen-DNA and Propidium Iodide-DNA (H2c to 4c) were more frequent and a greater heterogeneity in the chromatin condensation was observed. In particular, the changes were more evident in the lobus vestibulolateralis; mainly in this area, which receives inputs from the lateral line, the Purkinje cells are scattered in the molecular layer. On the contrary, in the yellow eel these large cells occupy the zone near or within the granular layer. The data suggest a relationship between the degree of heterogeneity of Purkinje cells and the afferent systems of the cerebellar areas examined. The changes of cerebellar cytoarchitectonics may be expression of the higher degree of the swimming activity of silver eel.

Anguilla↗
PubMed1985

Cytochemical variations in Purkinje neuron nuclei of cerebellar areas with different afferent systems in Rana esculenta. Comparison between activity and hibernation.

The distribution pattern of the Feulgen-DNA values (nuclear cytochemical heterogeneity) which provides information on the functional state of Purkinje neurons was investigated in the lobus vestibularis and in the corpus cerebelli in active and hibernating frogs. In the corpus cerebelli, hibernation does not change greatly the nuclear heterogeneity of Purkinje neurons, while in the lobus vestibularis this neuron population becomes more homogeneous and shows more condensed chromatin. These data suggest a nerve conduction in the two areas which responds differently to the phenomenon of hibernation, entailing a lower activity of Purkinje neurons in the lobus vestibularis with respect to the corpus cerebelli. Furthermore, the examination of a portion of the vestibular nuclear complex revealed an opposite behavior: indeed, a higher homogeneity of the nuclear cytochemical patterns was observed during activity. This result is related to the function of this localization as center of stimuli integration.

Afferent Pathways↗
PubMed1984

DNA synthesis in the cerebellar Purkinje neurons of early postnatal rats: an extra DNA or a repair process?

DNA synthesis and Feulgen - DNA content in Purkinje neurons were examined in early postnatal rats exposed to cis-dichlorodiammineplatinum II (cis-DDP) and (3H) thymidine. Autoradiographic data revealed a significant although low labelling in control rats on postnatal day 10 to 11; the incorporation deeply decreased after cis-DDP administration. Cytophotometry showed formation of some Purkinje cells with hyperdiploid DNA content in control animals between postnatal day 11 and 16, whereas in cis-DDP treated rats all cells remained diploid. A close correlation between the formation of hyperdiploid Feulgen-DNA nuclei and the incorporation of (3H) thymidine provides new, indirect support for an actual DNA surplus in some Purkinje cells, although the incorporation of some of (3H) thymidine due to an enhanced turnover and or repair of DNA in Purkinje cells of 10 to 11 days old rats is not excluded.

Age Factors↗
PubMed1983

Methodological problems in the histochemical demonstration of succinate semialdehyde dehydrogenase activity.

Methodological aspects of the histochemical technique for the demonstration of succinate semialdehyde dehydrogenase activity (EC 1.2.1.24) (indicative of the degradative step of gamma-aminobutyric acid catabolism) have been analysed in rat Purkinje neurons, where gamma-aminobutyric acid has been shown to be a neurotransmitter, and in hepatocytes, where it is metabolized. During a histochemical incubation for the enzyme, artefacts of succinate dehydrogenase activity and the 'nothing dehydrogenase' reaction are produced. Inhibition of these artefacts by the addition of two inhibitors, malonate and p-hydroxybenzaldehyde, revealed specific reaction products. Formazan granules, which can be ascribed only to specific succinate semialdehyde dehydrogenase activity, are obtained by adding malonate to the incubation medium in order to inhibit both succinate dehydrogenase activity and nothing dehydrogenase. The formation of these granules is completely inhibited by p-hydroxybenzaldehyde, an inhibitor of succinate semialdehyde dehydrogenase activity. Different levels of succinate semialdehyde dehydrogenase activity were noted in Purkinje neurons. This activity was also found in hepatocytes, mostly in the portal area, but with a lesser degree of intensity and specificity. Indeed, non-specific formazan granules were still produced, because of the 'nothing dehydrogenase' reaction, even in the presence of malonate. Thus, a malonate-insensitive 'nothing dehydrogenase' reaction seems to be present in neural and hepatic tissues.

Aldehyde Oxidoreductases↗
PubMed1983

Histochemical patterns of succinic semialdehyde dehydrogenase activity within the Purkinje cell population during rat cerebellar histogenesis.

The histochemical detection of SSADH activity corroborates some crucial steps of the maturation of Purkinje neurons in rat cerebellum. The SSADH-specific activity seems to appear early, within the first week of postnatal life, in a few Purkinje cells. Around the 12th day most cells were SSADH positive, even if some were still negative. This period is an important step of postnatal histogenesis when many histological and physiological data show important neuronal changes. At the end of cerebellar histogenesis the SSADH activity showed the same pattern as in adult rats. Our findings suggest that in the Purkinje cell population the maturation does not occur simultaneously thus confirming the concept of "heterogeneity" (different functional states).

Aging↗
PubMed1983

Feulgen DNA pattern of Purkinje cells population in vertebrates with different cerebellar cytoarchitectonics.

Quantitative evaluations of Feulgen DNA contents were carried out at different hydrolysis times on Purkinje cell population and granular cells (2c controls) from catfish, frog and quail cerebella. At some hydrolysis times, the blood erythrocytes (2c controls) were examined too. The Feulgen DNA heterogeneity (2c, H2c, 4c) previously found in the rat, was observed in catfish and quail and it was clearly dependent on the different hydrolysis times. On the contrary in the frog, H2c and 4c values only were found. The analysis of the Feulgen hydrolysis kinetics showed a greater homogeneity of chromatin in frog Purkinje cells in comparison to the other species studied. From a comparative standpoint the patterns of Feulgen DNA of Purkinje cells were discussed in relation to the cerebellar size and structural complexity and its "functional importance".

Animals↗
PubMed1983

Effect of Denzimol, a new anticonvulsant drug, on rat cerebellum. Morphological and histochemical patterns of Purkinje cell layer.

The effects of Denzimol, a new anticonvulsant drug, were analyzed in the Purkinje cell layer of rat cerebellum. No modifications in the general histochemical and ultrastructural patterns were induced by chronic administration of the drug. A slight increase in the storage of lipopigments in the cytoplasm of Purkinje neurons was found. No effects on secondary fluorescence (indicative of changes in biogenic amines) were found while an increase in specific SSADH activity, a degradative enzyme in GABA metabolism was present. Some observed histological and ultrastructural alterations (presence of "balloned" Purkinje neurons showing, in particular, enlarged cisternae of the endoplasmic reticulum) may be a stress effect probably due to the gastric tube insertion by which the drug was administered.

Animals↗
PubMed1983

Chromatin organization in frog Purkinje neurons during the annual cycle: cytochemical and ultrastructural studies.

Feulgen-DNA microdensitometric and propidium Iodide-DNA (PI-DNA) microfluorometric evaluations were made in Purkinje cells of cerebella from hibernating frogs and from active frogs. Higher Feulgen-DNA/distribution area ratios and lower PI-DNA values were found in the hibernating frog (both at high and low fluorochrome concentrations). These data indicate a higher degree of chromatin compactness. During the activity period, the Feulgen-DNA/distribution area ratios are lower and the Feulgen-DNA content is higher; the corresponding higher PI-DNA values indicate a lower degree of chromatin condensation. Histochemical and ultrastructural data show clearly different distribution patterns of chromatin and ribosomes in the two periods. The overall results underscore lower activity of neurons and a greater homogeneity within the Purkinje cell population during hibernation.

Animals↗
PubMed1983

Effects of diphenylhydantoin on postnatal ontogenesis in the rat. Ultrastructural analysis of Purkinje neurons and hepatocytes.

An ultrastructural analysis of Purkinje neurons and hepatocytes was carried out at several stages of postnatal ontogenesis in rats born from dams administered diphenylhydantoin (DPH) during pregnancy and nursing. After DPH administration the signs of immaturity in the neurons both at cytoplasmic and nuclear level were particularly evident between the 4th and 17th day of postnatal life, while at the end of histogenesis the normal situation was recovered. Such delayed morphological maturation of the neurons is in agreement with the data showing that anticonvulsant drugs given during pregnancy slow down postnatal growth and mental development. At all stages examined, modifications, mainly concerning the distribution of glycogen and the increase in rough endoplasmic reticulum and free ribosomes, were also observed in hepatocytes. The examination of the placebo group revealed some signs of delayed maturation in Purkinje neurons at early histogenetic stages and some modifications of the normal pattern in the hepatocytes. The rôle of gastric tube in drug administration needs to be verified further.

Animals↗
PubMed1983

Fluorescence histochemical patterns of Purkinje cell layer in rat cerebellum after long-term phenytoin administration.

The effects of long-term Phenytoin (DPH) administration were studied on the cerebellum Purkinje layer of Sprague-Dawley rats. Histochemical qualitative studies were performed in order to investigate fluorescence patterns linked to degenerative pigment storage and to changes in biogenic amines. Specific tests for Falck's method and the microspectrofluorometric analysis of fluorescent bodies showed: a) an increase in storage lipopigment which, generally referred to in the literature as lipofuscin, partially exhibit a more complex structure due to the simultaneous presence of lipofuscin and ceroids in the same granular body; b) a change in neurotransmitter patterns. This change must be typically related to an altered metabolism of biogenic amines and/or to degenerative phenomena causing the accumulation of biogenic amines in nerve terminals. The morphological and histochemical pictures support the idea of a generalized Purkinje cell damage.

Animals↗
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↗
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↗
PubMed1980

The Feulgen hydrolysis kinetics in the midgut cell classes of the stick insect Bacillus rossius: a computer analysis.

In the midgut epithelium of the walking stick insect Bacillus rossius, nuclei belong to two main cytological categories: nuclei with ordinary chromatin (ON) showing a polyploid series of Feulgen-DNA contents (2, 4, 8, 16C) and nuclei with DNA-RNA bodies (NWB) varying from 9 to 34C. Cells with ON are either small basal or large secretory elements, while those with NWB always belong to the second type. The Feulgen kinetics profiles obtained after formalin fixation, as well as their least squares fit by computer analysis, have shown that with increasing ploidy both the aldehydic group availability and the resistance to depolymerization increase in the genomes of ON; on the contrary, NWB have a depurination rate and resistance to depolymerization significantly lower than the ON. The kind and magnitude of the changes observed, while suggesting a gradually different DNA-protein relationship with increasing ploidy and concurrent maturation of ON, also indicate a deeper chromatin reorganization for NWB.

Animals↗