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C Melchiorri

Publications and source records attributed to C Melchiorri.

At least 37 records · Page 2Linked to original sources
PubMed1993

Ploidy and nuclearity of rat hepatocytes after compensatory regeneration or mitogen-induced liver growth.

The distribution pattern of rat liver parenchymal cells of different ploidy classes was investigated in Wistar rats following cell proliferation induced by surgical partial hepatectomy (compensatory regeneration) or primary mitogens (direct hyperplasia). Animals were killed at 1, 2, 3, 4 and 15 days after the proliferative stimulus, and ploidy and nuclearity were measured using a computer-assisted imaging system in hepatocytes isolated by collagenase perfusion. Analysis of hepatocytes from animals undergoing regeneration after partial hepatectomy revealed a large increase in tetraploid and octoploid mononucleate cells. The most striking feature was the almost complete disappearance of binucleate cells (from 20% to < 1%) at 3 days after partial hepatectomy. On the contrary, when hepatocytes were analyzed after treatment with the mitogen lead nitrate, a high number of binucleate cells (40%) was observed. The increase that was maximal at 3 days after treatment occurred mainly in 4 x 2c and in 8 x 2c compartments. This resulted in an overall increase in the ratio of binucleate/mononucleate cells as well as in the ratio (8c + 16c):(2c + 4c). The cytological changes induced by lead nitrate were not reversible 2 weeks after treatment. Because a massive elimination of excess liver cells occurred by apoptosis during this time period, it appears that polyploid cells are not preferentially eliminated. The hepatic content of DNA at the end of the regression phase was similar to control values. However, because of the higher ploidy state, the number of cells present in the liver 2 weeks after treatment appears to be lower than that of controls (approximately -16%). When liver growth was induced by a single treatment with another mitogen, the peroxisome proliferator nafenopin, a slight increase in the ploidy state of the liver was observed; because of the shift towards higher ploidy classes (8c), the increase in DNA content observed 3 days after a single treatment with nafenopin (+21%) appears to be almost entirely justified by polyploidy rather than by a hyperplastic event.

Animals↗
PubMed1993

A rapid and simple staining method, using toluidine blue, for analysing mitotic figures in tissue sections.

Mitotic index is a clinically important parameter in cancer pathology. We developed a staining method using Toluidine Blue to detect efficiently and rapidly mitotic figures in sections of formalin-fixed paraffin-embedded human and rat tissues. Sections were stained at acid pH with a 0.01% Toluidine Blue solution after removal of RNA with hydrochloric acid or ribonuclease. The optimal pH of the TB staining solution was found to be 4.5 for rat tissues and 3.5 for human tissues. This procedure stained mitotic figures much more intensely than other (extra)cellular structures. A quantitative estimate of the total number of nuclei in the field where mitotic figures were counted, was obtained in an adjacent section hydrolysed in 5 N hydrochloric acid and stained by the Feulgen reaction with a Schiff-type reagent containing 0.01% Toluidine Blue. This method specifically stained interphase and mitotic nuclei and the field cellularity could be quantified by image cytometry. When these procedures were performed on two consecutive serial sections, a mitotic index could be determined accurately by relating the count of mitotic figures to the number of tumour cells.

Animals↗
PubMed1991

A multifaced DNA ploidy analysis to determine ovarian carcinoma aggressiveness.

A microfluorometric DNA study was conducted on isolated cells from 64 fragments of ovarian epithelial tumors. Data analysis considered the DNA content of the main stemline and the prevalence of cells in the different compartments of the DNA ploidy histogram in relation to the mitotic activity index and the histologic architecture. Main stemlines were found remarkably stable in different parts of the same tumor. Peridiploid (1.8c to 2.2c) stemlines were found both in well-differentiated and in poorly differentiated tumors. However, low aneuploid (2.2c to 3.0c) stemlines were mostly found in nonsolid tumors and high ploidy (3.2 to 5.04 c) stemlines were prevalent in solid tumors. A comparative analysis between DNA ploidy parameters and mitotic activity was useful to evaluate the expanding modalities of neoplastic cell populations. This analysis revealed that several tumors accumulate an excessive amount of heteroploid cells and others an excessive amount of G2 cells. Yet, most neoplastic cell populations vary from slow to rapidly growing patterns without relevant abnormalities in their ploidy graphic profiles. No relationship was found between stemline ploidy and histologic architecture compared with expanding modalities. These findings indicate that multifaced criteria combining features such as main ploidy, graphic profile, mitotic rate, and histologic architecture measured on one or more microsamples of the same tumor may help to objectively estimate the aggressiveness reached by the neoplastic cells at the time of clinical presentation.

Carcinoma↗
PubMedDate not supplied

[Cadmium in the total diet of the typical Italian collective].

An inquiry, by the "Duplicate Portion" technique, has been made to estimate the daily assimilation of cadmium in various collectivities of Rome, representative of different economical-social and sanitary realities. At this regard, 132 complete meals, coming from a hospital canteen, a nursing home for old people, a big company, a community of students and an agricultural firm, have been examined. The sample has been mineralized to white ashes and analyzed in spectrophotometry at A.A. with a little oven of graphite. The data about cadmium assimilation, that we have obtained, are included between 12 and 25 micrograms/day and they are placed at medium-low levels, if we compare then with an assimilation of 15-60 micrograms/day, carried from studies on various populations. No daily data exceeded the limit of tolerability of 57-71 micrograms/day suggested from the W.H.O. Our data, coming the point, do not indicate a particular situation of danger for the groups of population we have studied.

Cadmium↗