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J Pierrez

Publications and source records attributed to J Pierrez.

9 recordsLinked to original sources
PubMed1992

Flow cytometric analysis of the cell cycle: mathematical modeling and biological interpretation.

Estimation of the repartition of asynchronous cells in the cell cycle can be explained by two hypotheses: the cells are supposed to be distributed into three groups: cells with a 2c DNA content (G0/1 phase), cells with a 4c DNA content (G2 + M phase) and cells with a DNA content ranging from 2c to 4c (S phase); there is a linear relationship between the amount of fluorescence emitted by the fluorescent probe which reveals the DNA and the DNA content. According to these hypotheses, the cell cycle can be represented by the following equation: [formula: see text] All the solutions for this equation are approximations. Non parametric methods (or graphical methods: rectangle, peak reflect) only use one or two phase(s) of the cell cycle, the remaining phase(s) being estimated by exclusion. In parametric methods (Dean & Jett, Baisch II, Fried), the DNAT(x) distribution is supposed to be known and is composed of two gaussians (representative of G0/1 and G2 + M) and a P(x,y) function representative of S phase. Despite the generality, these models are not applicable to all sample types, particularly heterogeneous cell populations with various DNA content. In addition, the cell cycle is dependent on several regulation points (transition from quiescence to proliferation, DNA synthesis initiation, mitosis induction) and biological perturbations can also lead to cytokinesis perturbations. Before the emergence of flow cytometry, the current view of cell cycle resided in the assessment of cell proliferation (increase in cell number) or the kinetic of molecules incorporation (DNA precursors).(ABSTRACT TRUNCATED AT 250 WORDS)

Cell Cycle↗
PubMed1991

Use of diploid and triploid trout erythrocytes as internal standards in flow cytometry.

DNA content determination requires the use of standards. Vindelov has shown the need to use two standards. Chicken and trout erythrocytes are commonly used, but they are not ideal standards. On the one hand, their DNA contents rarely frame the studied sample DNA content, and, on the other hand, as their base compositions are different in terms of A + T/G + C, their relative indices change according to the stains used. Use of triploid trout erythrocytes instead of chicken erythrocytes allows elimination of these two drawbacks; however, diploid trout must be differentiated from triploid trout. The present paper shows that an anatomic malformation is found with the triploid trout and so justifies the use of paired diploid and triploid trout as standards to measure nuclear DNA content.

Animals↗
PubMed1990

Time-variations of pretreatment peripheral blood S + G2/M-phase size determined by flow cytometry in adult acute myeloid leukaemia.

The circadian and seasonal variations of pretreatment proliferative activity of peripheral blood (PB) as PB S + G2/M-phase size was determined by flow cytometry in 61 adult patients with acute myeloid leukaemia (AML). Pretreatment PB S-phase (p less than 0.002), G2 + M-phase (p less than 0.008) and S + G2/M-phase size are statistically correlated to the time of sampling, with the highest phase size at the end of the day. Time-variations of the blast cell count are slightly significant (p = 0.049). Cytological diagnosis-related differences in S + G2/M-phase (p less than 0.003) and white blood cell count (p less than 0.04) time-variations are observed. For all patients, no seasonal variations can be drawn, but in AML 1 (p less than 0.029) and AML 4-5 patients (p less than 0.003), the circadian variations of S + G2/M are affected by the seasons. The present results suggest that time may be taken into account in the monitoring of chemotherapy in acute leukaemia.

Adult↗
PubMed1989

Prognostic significance of peripheral blood S + G2/M phase size in adult acute non-lymphoblastic leukaemia.

Flow cytometric analysis of peripheral blood (PB) S + G2/M phase size was performed in 73 adult patients with untreated acute non-lymphoblastic leukaemia, to assess whether the results may correlate to response rate and patient prognosis. All patients were treated with the same induction chemotherapy regimen: ARA-C alone or in combination with an anthracycline antibiotic. Pretreatment PB S + G2/M phase size is significantly correlated to induction response rate (p less than 0.02), duration of response (p less than 0.02) and duration of survival. Patients with low PB S + G2/M phase size experience a longer survival, in patients over and below 50 yr (p less than 0.001). Lastly, early deaths tend to be more frequent in the high median age and high PB S + G2/M phase size group. Our study suggests that PB S + G2/M phase size has prognostic significance in obtaining response and duration of survival.

Adult↗
PubMed1988

Flow cytometric analysis of DNA content differences in blood samples obtained by leucoconcentration.

The leucoconcentration technique allows rapid obtainment of cellular suspensions from total blood or bone marrow for flow cytometric analysis. The technique is based on picric acid in ethyl alcohol fixation and saponin red cell lysis, followed by mithramycin staining for DNA. It gives a good resolution of DNA distributions that allow detection of slight variations in DNA content. These results were obtained with cellular suspensions differing only in one X or Y chromosome (male, female, Klinefelter and Turner syndromes). In these studies the ratio of the DNA content of X and Y chromosomes agrees with the chromosomal mass ratio already reported by other authors, but the "absolute values" are 10-fold more compared to these same works. Our conclusion is that leucoconcentration technique followed by DNA staining with mithramycin increases the difference in the dye's penetration and binding between X and Y chromosomes.

DNA↗
PubMed1988

[Flux cytometry of the cellular cycle of leukemic cells of the blood].

The coordination of flux cytometry and of a techniques of leukoconcentration allowed to determine the cellular cycle of nucleated cells of circulating blood, without logs nor enrichment of cellular type on a definitive moment. The study of acute leukemias allow to conclude that: 1) it exists in peripheral blood a synthetic activity of ADN bound to the presence of leukemic or blastic cells; 2) this activity allows to appreciate the spontaneous variations of synthesis and the incidence of chemotherapy.

Adult↗
PubMed1987

Technique and staining optimization leucoconcentration.

In cytometric clinical application, it is important to obtain cell suspensions rapidly with as little cytological alteration as possible. A procedure has been achieved to prepare cell suspensions for flow cytometric analysis. The leucoconcentration technique, first described by Herbeuval for cytologic analysis, has been modified to be applied in cytometry. This technique involves Saponin lysis of red cells of peripheral blood or bone marrow samples that have been previously fixed with picric acid alcohol solution. Cells in suspension are not shifted and tinctorial affinity is not modified. Then cells have been stained with Mithramycin. Each parameter defined by Crissman has been analyzed to define the best staining conditions. The availability of Leucoconcentration with Mithramycin-DNA-staining permits determination of cell cycle with a fine resolution.

Bone Marrow Cells↗
PubMed1987

Modifications of the thymus and splenic thymic dependent zones after in utero exposure to phenytoin: qualitative and quantitative analysis in C3H mice.

Pregnant female mice were randomly distributed in two groups and received twice a day by gavage either 25 mg/kg Dilantin in 0.2 ml distilled water or 0.2 ml distilled water till full term. The offspring were sacrificed on day 5. In the exposed group, the thymic cortex was reduced with a low mitotic activity in the lymphoid population while reticuloepithelial tissue was enlarged; numerous interdigitated reticular cells accumulate at the cortico/medulla border. In the spleen, the white pulp was enlarged because of lymphocytes accumulation in the periarteriolar sheets. In these two organs, the relative number of Thyl-2+, Lyt 1+ and Lyt 2+ T cell subsets were also modified showing especially a decrease in the thymus and an increase in the spleen of the Lyt 1+ cells. Since at the same time the thymus and the spleen of the females which reproduced the neonates are quite unchanged, it is concluded that the developing immune system of the fetal mouse is more susceptible to diphenylhydantoin than the immune system of the adult. This raises the question of the reversibility of this in utero acquired immune impairment.

Animals↗