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E Scherini

Publications and source records attributed to E Scherini.

At least 37 records · Page 2Linked to original sources
PubMed1991

Permanent alterations of the dendritic tree of cerebellar Purkinje neurons in the rat following postnatal exposure to cis-dichlorodiammineplatinum.

The aim of this study was to characterize further the effect of cis-dichlorodiammineplatinum (cisDDP) on cerebellar Purkinje neurons of the immature rat. Ten-day-old rats were treated with cisDDP subcutaneously and killed after 1, 7, 20 or 65 days. The cerebellar vermis was impregnated by the Golgi-Cox method to evaluate the extent of morphological maturation of the Purkinje cell dendritic tree. One day after treatment, the dendritic network of Purkinje cells of treated animals was poorly developed and the cell somata still showed numerous perisomatic processes. This indicates that cisDDP interferes with the organization of microtubules and microfilaments by the cell. Later, several abnormal shapes of the Purkinje cell dendritic tree were observed. These included: (1) elongated primary dendrites; (2) asymmetrical dendrites; (3) sprouting of secondary and spiny branches in two planes of the molecular layer; and (4) damming of spiny branchlets at the pial surface. Moreover, all the dendritic networks of Purkinje cells in treated animals were of a lower Strahler order than in controls. All these data suggest that the late anomalies of the dendritic trees are secondary to the general cisDDP-induced damage of the cerebellar cortex, rather than being a primary effect of the drug on the dendritic tree growth.

Animals↗
PubMed1991

Changes in cell cycle and chromatin distribution in C6 glioma cells treated by dibutyryl cyclic AMP.

C6 glioma cells in culture were treated with 1 mM dibutyryl cyclic AMP (Db-cAMP) for 5, 8, 24 and 72 h. The cells were labelled with [3H]-thymidine before either the end, or the beginning, of the Db-cAMP treatment. The cell cycle passage was monitored by the simultaneous determination of DNA content and DNA synthesis in propidium iodide stained autoradiograms. The data revealed an early (t less than or equal to 3-8 h) and moderate inhibitory effect of Db-cAMP on all phases of the cell cycle except mitosis; some cells (2%) were completely blocked in the S phase. Later (8 less than t less than 24-72 h), the cycling of a substantial part of the population became inhibited in G1 phase. Microdensitometric texture analysis of Feulgen-stained nuclei, performed 24 h after administration of Db-cAMP, showed a higher inhomogeneity of the DNA distribution in cell nuclei, caused by the condensation of a part of the chromatin. This may reflect either changes in genome expression taking part in the process of cAMP induced differentiation or transit of some cells into quiescent G0 or S0 phases.

Animals↗
PubMed1990

Premitotic DNA synthesis in the brain of the adult frog (Rana esculenta L.): an autoradiographic 3H-thymidine study.

Replicative synthesis of DNA in the brain of the adult frog was studied by light microscope autoradiography. Animals collected during the active period (May-June) and in hibernation (January) were used. In active frogs, 3H-thymidine labelling occurred mainly in the ependymal cells which line the ventricles. The mean labelling index (LI%) was higher in the ependyma of the lateral and fourth ventricles than in the ependyma of the lateral diencephalon and tectal parts of the mesencephalon. In the recessus infundibularis and preopticus the number of labelled cells (LCs) was several times greater than in the lateral parts of the third ventricle. LCs were seen subependymally only occasionally. The incidence of LCs in the parenchyma of the brain was much lower in most regions than in the ventricular ependyma; LCs were mainly small and, from their nuclear morphology, they were glial cells. The LI% reached the highest value in the septum hippocampi and in the nucleus entopeduncularis. In these locations, LCs were larger and closer in size to the nerve cells of these regions. From comparison with data obtained earlier in the brain of mammals, it is evident that the distribution of proliferating cells in the olfactory and limbic system is phylogenetically conservative. The occurrence of pyknotic cells in the same areas which contain LCs, suggests that cell division reflects in part the process of cell renewal observed in mammals. However, proliferating cells could also be linked to the continuous growth observed in non-mammalian vertebrates. In hibernating frogs, LCs and pyknoses were not seen or were found occasionally, which further indicates the functional significance of both processes.

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PubMed1990

Developmental patterns in the rat cerebellum after cis-dichlorodiammineplatinum treatment.

A cytochemical study was made of some metabolic enzymes in the cerebellar neurons during postnatal ontogenesis after injection of cis-dichlorodiammineplatinum into 10-day-old rats. The profiles during development of neuron-specific enolase immunoreactivity (involved in the glycolytic pathway), dihydrofolate reductase activity (involved in the metabolism of nucleic acids and folate) and dipeptidylaminopeptidase II activity were determined in lobules V-VII of cerebellar vermis. At different developmental stages, treated rats had folia in which the morphology and cytochemical responses of Purkinje neurons were greatly affected. On postinjection day 1 (PD 11), only neuron-specific enolase immunoreactivity was changed, reactions being more intense at the basal pole, which was abnormally enlarged in several neurons. Seven days after treatment (PD 17), the dihydrofolate reductase reaction showed weakly positive cells with small grains of formazan in the perinuclear regions and dipeptidylaminopeptidase II activity, which had appeared at this time in some cells of the controls, was not observed. On PD 25 and PD 35, Purkinje cells, probably undergoing clear degeneration, were negative or very weakly positive in all the reactions. Some tracts of folia had no Purkinje cells. These results suggest that cis-dichlorodiammineplatinum affects the differentiation of Purkinje neurons and interferes first with the glycolytic enzyme and then with some enzymes of the synthetic and catabolic machinery, leading to cellular dysfunction and degeneration.

Aging↗
PubMed1989

Seasonal changes in the nucleoli of Purkinje cells of the hedgehog cerebellum.

A relationship between size and shape of nucleolus and cellular metabolic demands can be seen from measurements of Purkinje cell nucleoli in cerebellar hemispheres during the annual cycle of the hedgehog. During hibernation, nucleoli are smaller than during activity. The extent of the associated heterochromatin increases from activity to the beginning of hibernation. Moreover, during activity it is mostly distributed in small masses all around the nucleolus, while during hibernation it is clumped in a single mass. Data indicating a lesser protein synthesis by neurons during hibernation agree with electrophysiological indications that during hibernation the cerebral cortex, linked to the cerebellar hemispheres via afferent systems, is silent.

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PubMed1989

Ectopic Purkinje-like cells are GABAergic: immunohistochemistry with an immune serum against glutamic acid decarboxylase.

Intensely stained cells are found in the cerebellar white matter of the vermis and paravermis in adult rats after immunoreaction with an immune serum raised against glutamic acid decarboxylase (GAD). The cells are similar in size to cortical Purkinje cells and three times the size of Golgi cells of the internal granule layer, and have a thick immunopositive cell process emerging from a well-defined cytoplasmic cone. In the cytoplasm, immunoprecipitates are more dense around the nucleus as in normally located Purkinje cells. The morphological appearance of the immunopositive cells suggests that they may be ectopically located Purkinje cells. The soma of the ectopic Purkinje cells is contacted by a few darkly stained terminal boutons. Data indicate that, in spite of the different cellular environment, ectopic Purkinje cells can develop not only the typical morphological pattern already described but also other intrinsic features, such as their typical inhibitory neurotransmitter.

Animals↗
PubMed1989

Chromatin changes in frog neurons after eighth nerve transection.

Fourteen days after unilateral eighth nerve transection in the frog, Purkinje neurons of the lobus vestibulolateralis and corpus of the cerebellum and medium-sized neurons of the vestibular nuclear complex showed changes in metabolic activity. In the ipsilateral parts, and to a lesser extent in the contralateral parts, of operated frogs, the Feulgen-DNA values were higher and the nuclear areas larger, associated with decondensation of chromatin. The cytoplasmic basophilia was also less. These changes could be due to anabolic responses of the neuronal populations during regeneration. The anabolic reaction of the corpus cerebelli and contralateral vestibular nuclear complex is only partially non-specific and ascribable to the surgical trauma (comparison between sham-operated and unoperated frogs). The results indicate clear patterns of connection between the ipsilateral and contralateral parts and between the cerebellar and vestibular nuclear complex neurons.

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PubMed1988

Intranuclear differences in the response of Purkinje cell DNA of the rat cerebellum to bleomycin. A microphotometric and autoradiographic study.

A single dose of the DNA-binding cytostatic agent bleomycin (100 micrograms/g body weight, subcutaneously) was given to 10-day-old rats to study unscheduled repair DNA synthesis in nucleolar and in bulk nuclear chromatin of postmitotic Purkinje neurons. The Feulgen reaction and Hoechst 33342 staining were used for quantitative evaluation of nuclear DNA content and chromatin structure. The repair synthesis of DNA was detected by 3H-thymidine autoradiography. The data showed a lesser staining of Purkinje as well as granule cell DNA by Hoechst 33342 in bleomycin-treated animals than in controls, but there was no difference in staining with the Feulgen reaction. The mechanisms of DNA staining by both cytochemical methods suggest that bleomycin reacted preferentially with AT-rich and single stranded DNA in cerebellar cells in vivo. Weak 3H-thymidine labelling was found in Purkinje cells of both control and treated rats, but in the latter group the labelling was more pronounced near or over the nucleolus. The enhanced unscheduled DNA synthesis in the nucleolar region of Purkinje cells of treated animals may be due to greater damage of DNA in this region or may indicate a greater ability of the nucleolar chromatin to repair its DNA.

Animals↗
PubMed1987

Damage and repair of the immature rat cerebellum after cis-dichlorodiammineplatinum II (cis-DDP) treatment. An ultrastructural study.

The aim of this electron microscopy study was to further investigate the effects of cis-dichlorodiammineplatinum (cis-DDP) on the cerebellum of the immature rat. Ten-day-old animals were treated with cis-DDP subcutaneously and killed after 1, 7, 15 or 21 days. On postinjection day 1, cis-DDP effects were evident mainly in the external granular layer, with nuclear damage in many dividing cells, while their cytoplasm appeared to be less affected. Some binucleate cells were also present. On the contrary, in postmitotic or more differentiated cells, only cytoplasmic alterations were found. At later stages (postinjection day 7), the frequency of damaged cells in the external granular layer decreased, but there was a cellular deficit in the internal granular layer. Many postmitotic neurons underwent coagulative necrosis. Finally (postinjection days 15 and 21), the cellular deficit was partly compensated for by "reactive" structures, e.g., glial cell fibers, which underwent hypertrophy after initial edema. Moreover, packing densities of Bergmann astrocytes and oligodendrocytes were higher.

Animals↗
PubMed1987

Influence of cis-dichlorodiamineplatinum on glioma cell morphology and cell cycle kinetics in tissue culture.

C6 glioma cells (CCL 107) were cultured for three days and then treated with cis-dichlorodiamineplatinum (cis-DDP) at doses of 0.2-10 micrograms/ml medium. Changes in DNA synthesis and DNA content, as well as morphology of cells and chromatin distribution, were examined from the first post-treatment day onwards. The number of cells labelled with [3H]thymidine, detected autoradiographically, decreased after treatment with 0.2-10 micrograms/ml by approximately one half on post-treatment day 1 and diminished further by the third day after treatment. The labelled cells were entirely absent only after treatment with 10 micrograms/ml, 7 days post-treatment. Mitoses decreased from 1.4-0.6% by post-treatment day 1 and completely disappeared by day 3 (1 microgram/ml). Feulgen cytophotometry and propidium iodide cytofluorimetry revealed accumulation of cells in the S-phase, especially the latter part (0.5 and 1.0 micrograms/ml, post-treatment day 1) and subsequently also in G2 phase (post-treatment day 3). Incomplete cyto- and karyokinesis in some cycling cells was indicated by an increased number of binucleate cells and nuclei of higher ploidy classes. Labelled cells with intermediate DNA values were, on average, labelled less intensively, as was revealed by simultaneous measurements of DNA content and [3H]thymidine incorporation. Some cells displayed reduction in grain density over heterochromatin clumps. This would be in agreement with the late S-phase block of DNA replication. After post-treatment day 3 the density of cells in cultures was substantially lower.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1986

Influence of cis-dichlorodiammineplatinum on the structure of the immature rat cerebellum.

Groups of 6- to 7-day-old and 10- to 11-day-old rats received cis-dichlorodiammineplatinum (cis-DDP) or inactive trans-DDP subcutaneously and were killed after 1, 6, 10, 15, or 21 days. In both age groups the acute effect (postinjection day 1) was most obvious in the germinal external granular layer (EGL), where many cells underwent shrinkage necrosis (pyknosis, apoptosis); the latter were more frequent within the fissures than on the surface of the cerebellar folia. Cell debris were often seen to be engulfed by macrophages, Bergmann cell fibers, and meningocytes. Bergmann cell bodies were swollen and the nuclei of Purkinje cells as well as of surviving cells of the EGL were enlarged. No comparable effects were observed in animals that had received an injection of trans-DDP in the same dose. Toward postinjection (p.i.) day 6, pyknotic cells disappeared from the EGL or, after the larger doses of cis-DDP, substantially decreased in number. Small nests of pyknotic cells appeared, however, at some places of the internal granular layer (IGL). The EGL was discontinuous or thinner in both age groups. In the IGL and molecular layer (ML) multiple focal fresh hemorrhages appeared together with some macrophages. The packing cell density in the IGL was less than in the controls, especially at the top of the cerebellar folia, i.e., contrary to the distribution of the primary damage in the EGL. Later, at p.i. day 10, ectopic nests of the IGL occurred occasionally in animals injected when 10 to 11 days old and severe atrophy of the ML and Purkinje cell population was observed at some places. At p.i. days 15 to 21, invasion of microglia-like cells appeared in the IGL and in some regions of the ML. Occasionally, subpial hemorrhages occurred at this interval. The acute damage caused by cis-DDP is thus similar to the effect of X rays or some, but not all, drugs with a cytostatic action. In addition, a more profound influence on dividing cells of the EGL within the fissures and distinct capillary lesions, indicated by hemorrhages, were found after cis-DDP. As in other experimental models, the acute cis-DDP damage of the immature cerebellum was partly repaired within a few p.i. days. Spatial difference of the repair process was inferred from the packing cell density in the IGL measured at the top and bottom of the cerebellar folia.

Animals↗
PubMed1986

The annual cycle of Erinaceus europaeus L. as a model for a further study of cytochemical heterogeneity in Purkinje neuron nuclei.

The cytochemical heterogeneity of nuclei in Purkinje cells, which reflects differences in metabolic states within the population, has been studied by comparing cerebellar hemispheres of the hedgehog during periods of activity and hibernation. Cerebellar granule cells and hepatocytes served as controls for diploid cells. Three different cytochemical stains (Feulgen reaction, Propidium iodide and Hoechst 33342 fluorochromes) were used in order to evaluate by microdensitometry and microfluorometry how much the heterogeneity is dependent on the variations in DNA content and degree of chromatin compaction. In the active period, Feulgen-DNA values of Purkinje cells were more widely dispersed than in control cells. Some values (18-40% of the population) exceeded (hyperdiploid) the diploid value. With Propidium iodide and Hoechst 33342 (under conditions for quantitative evaluation of DNA), a few values also exceeded the maximum value for control cells. We conclude that there is nuclear heterogeneity (diploid-hyperdiploid) in the Purkinje neuron population during normal activity. The percentage of hyperdiploid nuclei changes according to the technique used; in particular, the comparison of the different stains indicates that a different chromatin compaction is mainly responsible for hyperdiploid Feulgen-DNA values, but in a few hyperdiploid cells there is an actual surplus of DNA. In view of the modalities of detection of DNA by the different cytochemical approaches utilized, this may be mainly single-stranded DNA. During hibernation nuclear heterogeneity is still present in Purkinje neurons, but with a shift of the distribution towards lower values; hyperdiploid nuclei were not detected with all the procedures used. Moreover, when Propidium iodide is used at the concentration suitable for qualitative studies, the dye intercalation is lower than during activity. Data suggest that both decreased DNA and increased chromatin compaction occur in Purkinje cells, thus pointing to a lower metabolic activity of these neurons in hibernating animals. The changes in diploid granule cells were always less than those in Purkinje neurons and could be ascribed to a further increase in chromatin compaction only, not requiring changes in DNA content.

Animals↗
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↗
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

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

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↗
PubMed1982

"Hyperdiploidy" in the Purkinje neuron population: chromatin status or extra-DNA? The influence of fixatives on Feulgen-DNA.

The influence of different fixatives (4% formaldehyde, methanol-acetic acid, methanol-formalin-acetic acid) and hydrolysis kinetics (performed at 23 degrees C and 60 degrees C) on the chromatin availability to the Feulgen reaction of cerebellar Purkinje neurons has been examined. The results show that formaldehyde preserves or even emphasizes the different availability to histochemical reactions for the detection of DNA. The existence of great heterogeneity in the Purkinje cell population, which cannot be detected in granule cells, is once again confirmed. The fact that mean values of DNA content are generally lower in granule cells than in Purkinje cells does not allow us to exclude that at least a small percentage of the highest values might be due to an actual extra DNA synthesis to a different extent.

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