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Biomedical subjects

C Pellicciari

Publications and source records attributed to C Pellicciari.

83 records · Page 5Linked to original sources
PubMed1980

Quantitative cytochemical study of chromatin during megakaryocyte maturation.

Several cytochemical parameters useful for characterizing the functional maturation of megakaryocytes were defined following a quantitative cytochemical investigation carried out on megakaryocytes which had completed the DNA synthesis stage. Variations in the ratio between nuclear DNA and cytoplasmic protein contents showed that, at any ploidy level, several maturation stages were concurrently present. The high variability in the basic protein content of the nucleus and in the Feulgen-DNA distribution area was related to the progressive chromatin condensation during thrombocytopoiesis. In particular, the results concerning the ratio between Feulgen-DNA and basic proteins in the nucleus, even after NaCl extraction of lysine-rich histones, pointed out the strong difference between megakaryocytes undergoing maturation and other proliferating cell populations. The different degree of genome activity within the same ploidy class was expressed by changes in the total DNA/double strand DNA ratio. The parallel trends of the DNA hydrolysis kinetics curves suggested a quite similar organization of chromatin in all the ploidy classes examined.

Animals↗
PubMed1979

Computer analysis of Feulgen hydrolysis kinetics.

A least squares fit of Feulgen hydrolysis time curves to the Bateman function is performed using an especially adapted parameter transformation together with a standard conjugate gradients iteration procedure. The method has been applied to a large number of measured data, and the use and limits of the computer evaluation are discussed.

Animals↗
PubMed1979

A case of acute myelomonocytic leukaemia associated with therapy: Feulgen-DNA microdensitometric determinations.

A cytochemical study of a case of acute myelomonocytic leukaemia, which arose after radiation therapy and polychemotherapy for Hodgkin's disease, is presented. The distribution of the DNA content of the circulating blood cells appears to be different from the unimodal diploid distribution reported in the literature for acute myelomonocytic leukamias not associated with therapy. This finding seems to strengthen the hypothesis, already put forward by Marinone et al. (1979), that a particular pattern of DNA content distribution could be characteristic of leukaemias linked to chemotherapy and radiotherapy.

Adult↗
PubMed1979

Repetitive DNA and Feulgen hydrolysis kinetics in three species of Bufo.

Two North American species of the genus Bufo (Bufo cognatus and Bufo boreas, 2n = 22) and one African species (Bufo regularis, 2n = 20) were analyzed with respect to their repetitive DNA fractions and the behaviour of their chromatin to the acid hydrolysis at different times. The mean melting point of the total isolated DNA decreased from 89 degrees C to 87 degrees C with a genome size increase from 4.4 to 7.5 pg. The differences in genome size can only partly be explained on the basis of repetitive DNA fractions (renaturing up to Cot 10 in 0.12 M phosphate buffer). Several fractions in this repetitive range behave independently in the three species and the spectrum of repetitive fractions in the African Bufo regularis differs distinctly from those of the American toads. When fixed chromatin of these species in histochemical preparations is hydrolyzed with 5N HCl during the Feulgen reaction, the kinetics of depurination are equal in all species, while hydrolytic DNA breakdown proceeds distinctly more slowly in Bufo reularis as compared to the other species.

Animals↗
PubMed1978

Methods of denaturation and renaturation of DNA in interphasic chromatin: cytochemical quantitative analysis by Methyl Green staining.

Almost diploid nuclei (as judged from the microdensitometric evaluation of the Feulgen positive material) of granular and Purkinje cells of the rat cerebellar cortex, were submitted to in situ DNA denaturation and renaturation experiments. We assessed the double-strandedness of DNA, by Methyl Green staining according to Scott (1967). Under these conditions a stoichiometric ratio between bound dye and DNA exists, suitable for quantitative microdensitometric measurements. Our data show that DNA in the interphasic chromatin is never completely denatured after the treatments we used. Furthermore, the renaturation takes place in a different way in the two cell types. Owing to the unlike chromatin packing of granular and Purkinje nuclei, we suggest that nuclear proteins must interfere differently on the in situ denaturation and renaturation processes.

Animals↗
PubMedDate not supplied

The Golgi apparatus is a primary site of intracellular damage after photosensitization with Rose Bengal acetate.

The aim of the present investigation was to elucidate whether the Golgi apparatus undergoes photodamage following administration of the fluorogenic substrates Rose Bengal acetate (RBAc) and irradiation at the appropriate wavelength. Human HeLa cells were treated in culture and the changes in the organization of the Golgi apparatus were studied using fluorescence confocal microscopy and electron microscopy, after immunocytochemical labeling. To see whether the cytoskeletal components primarily involved in vesicle traffic (i.e., microtubules) might also be affected, experiments of tubulin immunolabeling were performed. After treatment with RBAc and irradiation, cells were allowed to grow in drug-free medium for different times. 24 hr after irradiation, the cisternae of the Golgi apparatus became packed, and after 48-72 hr they appeared more fragmented and scattered throughout the cytoplasm; these changes in the organization of the Golgi cisternae were confirmed at electron microscopy. Interestingly enough, apoptosis was found to occur especially 48-72 h after irradiation, and apoptotic cells exhibited a dramatic fragmentation of the Golgi membranes. The immunolabeling with anti-tubulin antibody showed that microtubules were also affected by irradiation in RBAc-treated cells.

Fluorescent Dyes↗
PubMedDate not supplied

Nucleolus disassembly in mitosis and apoptosis: dynamic redistribution of phosphorylated-c-Myc, fibrillarin and Ki-67.

The nucleolus may undergo disassembly either reversibly during mitosis, or irreversibly in apoptosis, thus allowing the redistribution of the nucleolar proteins. We investigated here by immunocytochemistry the fate of three representative proteins, namely phosphorylated c-Myc, fibrillarin and Ki-67, and found that they behave independently in both processes: they relocate in distinct compartments during mitosis, whereas during apoptosis they may either be cleaved (Ki-67) or be extruded into the cytoplasm with a different kinetics and following an ordered, non chaotic program. The separation of these nucleolar proteins which occurs in early apoptotic nuclei continues also in the cytoplasm, and culminates in the final formation of apoptotic blebs containing different nucleolar proteins: this evidence confirms that the apoptotic bodies may be variable in size, content and surface reactivity, and include heterogeneous aggregates of nuclear proteins and/or nucleic acids.

Apoptosis↗