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Biomedical subjects

G Mazzini

Publications and source records attributed to G Mazzini.

At least 73 records · Page 4Linked to original sources
PubMed1985

Validation of a mathematical procedure for computer analysis of flow cytometric DNA data in human tumors.

The determination of tritiated thymidine labeling index and the percentage of cells with S phase DNA content was performed on cell suspensions obtained from 69 patients with non-Hodgkin's lymphoma. The distributions of cells in the cell cycle by computer analysis of flow cytometric data were obtained by two mathematical procedures: the widely adopted Fried model and a new one proposed by Bruni et al. A significant agreement was observed by checking the Spearman index (rs) between the percentages of cells in the different cell cycle phases (G0/1, rs = 0.76; S, rs = 0.60; and G2 + M, rs = 0.43; p less than 0.001) determined by the two procedures. Similarly, a good correlation was observed between the labeling index (LI) and the S phase values obtained by the Fried (rs = 0.45, p less than 0.001) and Bruni (rs = 0.69, p less than 0.001) models, but with a higher agreement for the latter one. The S phase by the Bruni model was also superior in predicting LI: in fact, by employing the S cutoff value of 12%, a better agreement between low LI and low S phase or high LI and high S phase was observed with the Bruni procedure (90%) than with the Fried model (72%). Finally, the analysis of the prognostic significance of the different kinetic variables confirmed the prognostic relevance of LI at any time; the S phase percentage as determined by Bruni et al. was discriminant of survival only at shorter times, and no prognostic significance could be ascribed to S phase according to the Fried procedure.

Adult↗
PubMed1985

Propidium iodide staining of cytoautoradiographic preparations for the simultaneous determination of DNA content and grain count.

A new method is described for staining cell nuclei with propidium iodide in preparations that have been processed for autoradiography. The permeability of the stripping film to the dye molecule has been studied, as have the staining conditions, in order to optimize the stoichiometry of the DNA-dye interaction. A procedure has also been set up to allow the simultaneous measurement of DNA content and grain count on the same cell.

Anemia, Hemolytic↗
PubMed1985

DNA content analysis of peripheral blood B-lymphocytes in plasma cell malignancies.

A double fluorescence assay has been employed for the detection of cell surface and/or cytoplasmic immunoglobulins (Ig) and the measurement of nuclear DNA content in the same cell. Following staining for Ig by means of FITC conjugated antibodies directed against heavy or light chains, cell suspensions or cytospin preparations were ethanol fixed and stained with a propidium iodide-RNAse solution. In this way, the cytometric DNA content of circulating B-lymphocytes was analyzed in three patients suffering from plasma cell malignancies with an excess of peripheral blood B-lymphocytes and evidence of aneuploid bone marrow plasma cells. Aneuploid circulating B-lymphocytes with the same DNA stem-line as bone marrow plasma cells were found in two patients with advanced disease but not in the only one we studied at presentation. Aneuploid lymphocytes had surface immunoglobulins bearing the same light chain as the M-protein. In addition, a significant percentage (23%) of cells lacking either surface or cytoplasmic immunoglobulins proved to be aneuploid in plasma cell leukemia. Nuclear DNA measurement combined with surface or cytoplasmic marker analysis appears to be a reliable method for studying neoplastic lymphoid precursor cells in plasma cell malignancies.

Aneuploidy↗
PubMed1984

Plasma cell DNA content in multiple myeloma and related paraproteinemic disorders. Relationship with clinical and cytokinetic features.

In 62 patients with multiple myeloma (MM) and related disorders, the nuclear DNA content distribution of bone marrow plasma cells was assessed by flow and conventional cytofluorometry. Abnormal distributions, suggesting the presence of aneuploid populations, were observed in 53% of MM at diagnosis, in 50% of benign monoclonal gammopathies and in 12% of Waldenström's macroglobulinemias. Eighty-six percent of aneuploid cases had DNA stem-lines falling between the diploid and triploid value. In advanced and relapsing MM, abnormal distributions were found in 75% of cases. In 4 out of 14 patients with MM serially studied during the course of disease, emergence of new abnormal clones was documented. The abnormal DNA content of bone marrow plasma cells was not correlated with any clinical and laboratory characteristic and it affected neither response to therapy nor survival in patients studied at diagnosis. In advanced phases of MM, the presence of abnormal clones was correlated with high plasma cell proliferation rates (studied by tritiated thymidine incorporation) and poor response to chemotherapy. Seven out of 8 patients in acute terminal phase of MM had abnormal clones. Among these, five had DNA stem-lines over triploid value.

Adult↗
PubMed1983

Proliferative activity of bone marrow cells in primary dysmyelopoietic (preleukemic) syndromes.

The proliferative activity of bone marrow cells was studied in 24 patients with primary dysmyelopoiesis by means of flow cytometry and 3H-TdR autoradiography. Abnormal DNA content was found in two cases with aneuploid karyotypes. DNA content typical of a diploid population was observed in all patients with normal karyotype and in three patients with chromosomal aberrations. The fraction of bone marrow cells in S- and G2-phase was higher in primary acquired sideroblastic anemia and refractory anemia (without excess of blasts) than in refractory anemia with excess of blasts and chronic myelomonocytic leukemia. Regardless to the diagnosis, the patients with low fraction of cells in S- and G2-phase had short survival time and showed high rate of evolution into acute nonlymphoblastic leukemia. The labeling (LI) and mitotic (MI) indexes of both erythroblasts and granulocytic cells were decreased in nearly all patients. The lowest values of LI and MI of the granulocytic compartment were found in the patients who subsequently developed acute leukemia. These data suggest that cytokinetic analysis allows investigators to achieve useful information on the stage of disease in the dysmyelopoietic syndromes.

Adult↗
PubMed1983

Flow cytometric DNA content in myelodysplastic syndromes.

DNA flow cytometric analysis of unfixed bone marrow cells stained with propidium iodide was carried out in 33 patients with untreated primary myelodysplastic syndromes. Patients with stable clinical course for up to 3 years had higher fractions of cells in S and G2 phases (22.7 +/- 12.4% and 12 +/- 3.6%) than those who developed acute leukemia and/or died early in the course of disease (14.4 +/- 8.5% and 6.6 +/- 4%). Median survival was more than 36 mo in patients with S + G2 cell fraction higher than 24%, and 14 mo in the remaining 16 patients with lower values (P less than 0.01). Analyses repeated after 3-24 mo showed no major changes in cell proliferation pattern in ten out of 11 patients. The remaining patient had sharp decrease in S and G2 cell fraction 3 mo before the transition into acute leukemia. The DNA index (DI) of bone marrow cells was calculated to assess ploidy. However, comparative evaluation of cytologic, cytogenetic, and flow cytometric data suggest that, under our experimental conditions, the DI may be influenced by factors such as the degree of chromatin compactness.

Adolescent↗
PubMed1982

Cell cycle analysis in a human cell line (EUE cells).

A new procedure to determine the durations of cell cycle phases is based on th autoradiography of labeled nuclei and a standard chemical determination of DNA content per cell. It has been used to study the cell cycle timing of a human established cell line, EUE cells, so far poorly characterized in its kinetic aspects. The cycle phase durations obtained with this method are compared with the DNA frequency profiles determined by flow cytometry and found to agree closely. The relevance of the growth conditions of the exponentially growing cultures for a correct estimation of the cycle phase duration is indicated. Cell size distribution has been shown to vary according to growth condition.

Autoradiography↗
PubMed1982

Sequential vincristine, arabinosylcytosine and adriamycin in acute leukemia: cytologic and cytokinetic studies.

Cytokinetic and cytocidal effects exerted on peripheral blood blasts by sequential administration of vincristine (VCR) 2 mg on day 1, arabinosylcytosine (Ara-c) 50-60 mg/m2/12 hr from day 2-4), and Adriamycin (ADM, Farmitalia, Milan, Italy, 40-60 mg/m2 on day 5) have been examined in 22 courses of treatment performed on 12 patients with nonlymphoblastic and in 4 with lymphoblastic acute leukemia. In 4 patients, the bone marrow blasts wee examined before and also after VCR-Ara-c administration. In vitro tritiated thymidine autoradiography and propidium iodide-DNA flow cytometry were employed for kinetic studies. Blasts disappeared from blood with a median half time of 35 hr. After VCR-Ara-c administration, a significant increase in labeling index (LI) and in the aliquot of cells with DNA content between the diploid (2n) and the tetraploid (4n) values was observed in 80% of the courses in peripheral blood blasts and in all courses in bone marrow blasts. The median grain count over the labeled nuclei was decreased, and the 4n cell percentage and the bone marrow blast mitotic index did not increase. These findings suggest that the increase in the S phase fraction of blast population is due to cell synchronization. Increase in the S phase appears to heighten the cytocidal effect of ADM. The aliquot of the blasts cleared from blood after ADM were in fact related directly to the degree of labeling index increase observed during the previous administration of VCR and Ara-c.

Acute Disease↗
PubMed1981

DNA content and kinetic characteristics of non-Hodgkin's lymphoma: determined by flow cytometry and autoradiography.

The determination of DNA content and [3H]thymidine labeling index was carried out on malignant lymph nodes from 74 patients with non-Hodgkin's lymphoma. Analysis of cellular DNA content was performed using propidium iodide as DNA-specific fluorescence dye. The ploidy was expressed as the DNA ratio between the relative DNA content of the human lymphoid G0/1 cells to that of chicken red blood cells. Forty-five of the 74 non-Hodgkin's lymphomas (61%) were aneuploid populations and the majority of these (91%) showed a hyperdiploid DNA content. A higher frequency of aneuploidy (72%) was observed in tumors with unfavorable histology than in those with a favorable histology (55%). Moreover, among aneuploid lymphomas heterogeneous populations were observed in 24% of the cases. The evaluation of flow cytometric data using Fried's deconvolution procedure showed no statistically different frequency of G0/1, S and G2 + M cells between the two groups of tumors with favorable and unfavorable histology. on the contrary, a statistically different frequency of G0/1 and S cells was observed between the two groups of tumors with low and high labeling indices (P less than 0.01). A correlation was found between autoradiographic and flow cytometric determination of S phase cells (P less than 0.001).

Aneuploidy↗
PubMed1981

Effect of vincristine on bone marrow cells of patients with multiple myeloma. A cytokinetic study.

The cytokinetic changes induced by Vincristine (VCR) on bone marrow erythroblasts, myeloid cells and neoplastic plasma cells have been studied in four patients with plasma cell malignancies using combined DNA cytofluorometry and in vitro tritiated thymidine cytoautoradiography. The changes observed 9 h after the administration of the drug were in accordance with its S-phase specificity. The magnitude of the stathmokinetic effect was in fact roughly proportional to the proliferative activity of the different cell lines, i.e., marked on the erythroblasts, less evident on the myeloid cells and still lower on the plasma cells. In this last cell population VCR has also blocked or partially impaired the DNA synthesis. Nine days after VCR, the plasma cells were recruited into the proliferative cycle while the regeneration of the hemopoietic cells was already exhausted. Repeated administrations of VCR spaced at about 9 day intervals are more and more effective on the plasma cell population, since the S place specificity of the drug against the recruited plasma cells is potentiated. On the contrary, the regeneration of the hemopoietic cells is protected by this time interval.

Autoradiography↗
PubMed1980

A rapid cytofluorometric method for quantitative DNA determination on fixed smears.

A study has been made of the possibility of using propidium iodide (PI) for the cytofluorometric determination of DNA in fixed smears. A preliminary spectrofluorometric study made it possible to define the optimal conditions for the excitation wavelength and the intensity of the emitted fluorescence. The stoichiometry and specificity of the DNA-PI bond were studied in different materials and for different fixation procedures. In order to check whether RNA might interfere, it was extracted enzymatically from test preparations selectively. The data from such treated sections were not significantly different from those obtained by means of the fluorescent Feulgen reaction (Pararosaniline-SO2) on the same material. On the other hand, some of the advantages of the PI method are important: (a) the time required for making ready and staining the preparations is very short, and in any case is considerably shorter than the Feulgen method; (b) the high quantum yield of the DNA-PI complex induces very high fluorescence intensities, which can, therefore, be easily measured, even with low sensitivity instruments; (c) the spectral conditions are particularly favourable for excluding the inner filter effect from the measurement; (d) the photo-decomposition is considerably lower compared to that found in preparations stained by the conventional Feulgen method. The wide possibility of excitation (from the u.v. to the green), together with the limited extent of the emission band (which is mainly in the red) are also conditions that are particularly favourable for obtaining multi-parametric determinations simultaneously from the same cell.

DNA↗
PubMed1980

Cytokinetic changes in the peripheral blood of leukemic patients during cytostatic therapy. V. Effect of VP 16 213 studied with flow cytofluorometry and cytoautoradiography.

The cytokinetic effects induced by VP 16 213 (50-60 mg/sqm/12 hrs for 10 doses) on the peripheral blood and bone marrow blasts of two patients with acute myelomonocytic leukemia have been studied using DNA flow cytofluorometry and in vitro tritiated thymidine cytoautoradiography. Besides a striking cytocidal effect, the drug induced cell synchronization in the G2 phase of the cell cycle as evidenced by the building up of tetraploid nuclei without an increase in mitotic figures. The synchronizing effect was greater in the bone marrow than in peripheral blood. In one patient, the removal of the G2 block was observed which paralleled an increase in proliferative activity. The usefulness of flow cytofluorometry for rapidly detecting the cytokinetic changes induced in acute leukemia blasts by cytostatic drugs is affirmed.

Autoradiography↗
PubMed1980

Cytokinetic changes in the peripheral blood of leukemic patients during cytostatic therapy. VI. Effect of arabinosylcytosine.

Flow and conventional DNA-cytofluorometry and in vitro tritiated thymidine cytoautoradiography were employed in the study of the cytokinetic changes induced by Ara-c on the peripheral blood blast cells of six patients with acute non-lymphoblastic leukemias. Nine courses of therapy were studied, in 5 of which Ara-c was administered in low pulse doses (20-60 mg/sqm) repeated every 12 hrs and in the other 4 it was administered in continuous infusion (90-150 mg/sqm) lasting 24 hrs. Low repeated pulse doses have little cytocidal effect and increase the 2n-4n cell percentage and, less markedly, the LI, while the median grain count is reduced. Many U-like cells and accumulation of 3H-TdR labeled blasts in early S phase were observed during therapy. The continuous infusion of Ara-c induces striking cytoreduction and concomitantly decreases the 2n-4n percentage and LI. Progressive recovery of 2n-4n percentage and LI over pretreatment values was observed 24-48 hrs after stopping infusion in one case and was probably due to cell recruitment following tumor mass reduction. Our data agree with the literature, which is briefly reviewed, in that they indicate that Ara-c in a low intravenous pulse frequently dose synchronizes the blasts in S phase while higher doses of the drug are more often cytocidal in S phase and cell recruitment can follow cytoreduction.

Adult↗
PubMed1980

Cytokinetic studies on circulating neoplastic cells of Hodgkin's disease.

In two patients with advanced Hodgkin's disease the DNA content, the mitotic index and the in vitro tritiated thymidine labeling index of the neoplastic cells found in peripheral blood, bone marrow and, in one case, in ascitic fluid have been determined. Cytologically the tumor cells were classified into three groups: atypical mononuclear cells, Hodgkin (H) cells and Reed-Sternberg (R-S) cells. Two populations with clearly different kinetic features were recognized. The first one was that of atypical mononuclear cells which exhibited diploid DNA content and proliferative activity of moderate degree: tetraploid cells were, however, observed more frequently than expected. The second population grouped together H and R-S cells, had tetraploid modal DNA content and very high proliferative activity. Hodgkin cells had tetraploid or slightly greater DNA content while R-S cells exhibited also DNA values as high as octoploid and sometimes greater. It can be postulated that by endomitosis some atypical mononuclear cells give origin to H cells and that these assume the monstrous features of R-S cells while increasing their DNA content during the DNA synthesis phase.

Adult↗