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Biomedical subjects

O Guerci

Publications and source records attributed to O Guerci.

At least 19 recordsLinked to original sources
PubMed1996

[Predictive value of intracellular accumulation of daunorubicin and P-glycoprotein expression simultaneously determined by flow cytometry in adult acute myeloid leukemias].

Multidrug resistance (MDR) phenotype expression was evaluated retrospectively in 87 patients with acute myeloid leukemia (AML), 69 with de novo AML, ten with relapsed AML and eight with AML secondary to myelodysplastic syndrome (MDS). MDR phenotype, characterized by P-glycoprotein expression (MRK16 monoclonal antibody) and decrease in intracellular daunorubicin (DNR) accumulation was determined using flow cytometry. All patients received chemotherapy including cytosine-arabinoside and anthracycline (daunorubicin, zorubicin, idarubicin) or mitoxantrone, and quinine in ten cases. The predictive value of the MDR phenotype for clinical responsiveness was studied using uni- and multivariate analyses. Univariate analysis showed that DNR accumulation (p < 10(-4)), P-glycoprotein expression (p = 10(-4)) and disease status (de novo versus recurrent AML and acute MDS) (p = 10(-4)) were predictive of clinical responsiveness. The significance of these three parameters was maintained in multivariate analysis. When de novo AML was considered, only DNR accumulation was of predictive value (p < 10(-4)) for complete response to chemotherapy.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1995

Predictive value for treatment outcome in acute myeloid leukemia of cellular daunorubicin accumulation and P-glycoprotein expression simultaneously determined by flow cytometry.

To evaluate the clinical relevance of multidrug resistance (MDR) phenotype, the intracellular daunorubicin accumulation (IDA) and P-glycoprotein (P-gp) expression were investigated in 87 adult patients with acute leukemia: 69 patients with de novo acute myeloid leukemia (AML), 10 with AML at relapse, and eight with secondary leukemia to myelodysplastic syndromes (MDS-AML). IDA and P-gp expression were determined by double-labeling flow cytometry analysis. Of 87 patients, 36 expressed P-gp (41%). P-gp expression was more frequently observed in AML at relapse and MDS-AML as compared with de novo AML (P = .0001). P-gp expression was significantly associated with CD34 expression (P = .0003) and chromosome 7 abnormalities (P = .027). A significantly reduced IDA was observed in P-gp+ as compared with P-gp- patients (P = .0007). Of the 87 patients, 51 achieved complete remission (CR). A reduced IDA was observed in patients in failure as compared with patients in CR (22% +/- 17% v 42% +/- 21%; P = 10(-4). Twelve of 36 P-gp+ patients as compared with 40 of 51 P-gp- patients achieved CR (33% v 78%; P = 10(-4). The prognostic value of IDA and P-gp expression was confirmed in multivariate analysis. These data suggest that the determination of IDA and P-gp expression may be useful in designing therapy for patients with AML.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1995

Refractory anemia with excess of blasts: a multivariate analysis of prognostic factors in 91 patients and a simplified scoring system for predicting survival.

Prognosis in myelodysplastic syndromes is extremely variable. The prognostic value of the FAB classification has been demonstrated in many studies. However, within the same FAB subtype, some patients may experience prolonged survival, whereas others die in a few weeks. This prognostic heterogeneity makes the therapy decision difficult. In an attempt to identify significant prognostic factors for survival in refractory anemia with excess of blasts (RAEB), clinical and hematological characteristics were analyzed in 91 patients. Multivariate regression analysis showed that bone marrow total blast cells percentages, sex and hemoglobin level were the characteristics significantly associated with survival. A scoring index based upon these three characteristics may be proposed and had a great prognostic value (p < 0.00001). It allows us to separate patients into three groups with low, intermediate and high score with a median survival of 239, 133 and 45 days for each group respectively. This scoring index may be useful in the design of therapy and analysis of future clinical trials. However, its predictive value needs to be confirmed in other series.

Adult↗
PubMed1995

Development of a criterion for response to therapy at 6 months in multiple myeloma.

UNLABELLED: To investigate the prognostic value of therapy at 6 months on survival in multiple myeloma, to develop a new criterion assessing response to initial therapy at 6 months, and to compare it to a current criterion. The types of initial and 6-month therapy were considered in a prognostic factor analysis in 70 patients treated in routine practice. Using the response to initial therapy defined by the clinician's decision as grouping variable in this group, a discriminant analysis identified the characteristics of responder patients. The validity of the resulting criterion was tested in another test group. Its prognostic ability was compared to the CLMTF criterion (50% M-component reduction from baseline). The therapy at 6 months, reflecting the clinician's appraisal of response to initial therapy, predicted survival significantly. A criterion combining two variables (M-component change and haemoglobin level at 6 months) classified 70% and 72.4% of patients correctly regarding response status in the training and test groups respectively. This criterion was shown to perform better than the CLMTF criterion in predicting survival. CONCLUSION: A new criterion for response to therapy at 6 months, also presented in a nomogram, combines M-component change and haemoglobin level at 6 months.

Aged↗
PubMed1994

Comparative evaluation of S9788, verapamil, and cyclosporine A in K562 human leukemia cell lines and in P-glycoprotein-expressing samples from patients with hematologic malignancies.

The activity of S9788, recently synthetized as a modulator of multidrug resistance (MDR), was compared with verapamil and cyclosporine A in normal sensitive and MDR K562 cell lines, then in samples from 33 patients with hematological malignancies, using flow cytometry with simultaneous detection of P-glycoprotein and determination of intracellular daunorubicin fluorescence. This technique was compared and correlated with a tritiated daunorubicin accumulation method. In K562 cell lines, S9788 exhibited a significantly higher reversing activity than verapamil and cyclosporine A, and allowed a complete restoration of the accumulation of daunorubicin when used at 5 mumol/L. In the clinical samples, the three compounds were evaluated at equimolar concentration (5 mumol/L) using concomitant exposure to daunorubicin and to the reversing agent. In P-glycoprotein-negative samples, no significant effect on intracellular daunorubicin fluorescence of any of the reversing agents was noted. In the 15 P-glycoprotein-positive samples, a significant increase in daunorubicin fluorescence, by at least one reversing agent, was seen in 10 cases, among which S9788 reversing activity was higher than that of the two other agents in seven cases. Complete reversal was only achieved in one case with S9788.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1992

Flow cytometric analysis of the cell cycle in chronic gastritis.

Flow cytometric cell cycle analysis was recorded in gastric biopsy specimens from patients with normal gastric mucosa (GM), superficial gastritis (SG) and chronic atrophic gastritis (CAG). Cell-cycle analysis showed significantly higher percentages of cells in S- and S+G2/M-phase in CAG than in SG and normal GM (P < 0.0001). Moreover, CAG with severe or moderate atrophy showed significantly higher percentages of cells in S-phase (P < 0.05) and S+G2/M-phase (P < 0.02) than CAG with mild atrophy in antrum. In fundus, even if this increase was observed, it did not reach statistical significance. Consideration of concomitant pathologic findings such as oesophagite, gastric or duodenal ulcer, duodenite or benign polyp allowed a better differentiation of CAG both in antrum and in fundus. Significantly higher S-phase was observed in CAG with severe or moderate atrophy than in CAG with mild atrophy (P < 0.05). No statistically significant results were observed in patients with normal gastric mucosa or chronic gastritis and a concomitant pathologic finding.

Cell Cycle↗
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↗
PubMed1984

H-2 control of polyadenylated mRNA production in the spleen of mice injected with Brucella antigens.

RNA was extracted from the splenocytes of Brucella abortus antigen stimulated mice and of control mice. The proportion of chromatographically separated polyadenylated 11.2S mRNA, was determined. With the technique used, only stimulated mice exhibited significant amounts of this RNA species. The highest level was reached 1 day after the stimulation, and the decay from this level presented an oscillatory form during the 4 weeks following the injection. In two different genetic backgrounds, H-2b mice did not respond to the stimulus, in contrast to H-2a and H-2f mice. H-2b/H-2f heterozygotes behaved roughly as intermediate between H-2b and H-2f mice. This genetic control seems to parallel the genetic control of some Brucella-induced, thymus-dependent events previously described.

Animals↗
PubMed1981

Multiple myeloma after phenytoin therapy.

We report a case of multiple myeloma in a 48-year-old woman treated with phenytoin for 55 months. This association may be fortuitous. The depressive effect of phenytoin on the immune responses, however, could account for the occurrence of the dysglobulinaemia. This case points out the need for periodic examination of serum proteins in patients chronically treated with hydantoin derivatives.

Female↗
PubMed1981

Separation of human bone marrow cells by sedimentation.

Sedimentation at unit gravity of human bone marrow cells, for 15 h at 4 degrees C on linear density gradient of Ficoll in culture medium ranging from 1.020 to 1.065 g/ml shows that a differential migration of the bone marrow cell sub-populations exists with precise mean densities 1.021 +/- 1 x 10(-3) g/ml for lymphocytes; 1.024 +/- 2.5 x 10(-3) g/ml for non-eosinophil granulocytes; and 1.055 +/- 10 x 10(-3) g/ml for metamyelocytes; 1.030 x 3.5 x 10(-3) g/ml for other myeloid cells (myeloblasts, promyelocytes, myelocytes); 1.040 +/- 1.040 +/- 3 x 10(-3) g/ml for eosinophil granulocytes; and 1.055 +/- 10 x 10(-3) g/ml for megakaryocytes. The highest percentages of S phase cell and G2 and M phase cells determined by a cytofluorograph correspond to the peaks of immature myeloid cells (myeloblasts, promyelocytes and myelocytes). This method of bone marrow cell separation may be used to study the cell cycle in pathological bone marrows (leukaemia in particular) and to determine the effects and the efficiency of some antimitotics.

Bone Marrow Cells↗
PubMed1981

[Application of sedimentation at 1 g on a Ficoll gradient to the separation of bone marrow cells].

Sedimentation at unit gravity of human bone marrow, during 15 hours at 4 degrees C on a linear density gradient of Ficoll in culture medium ranging from 1.020 to 1.065 g/ml shows that it exists a differential migration of bone marrow cells subpopulation with a precise mean densities : we find successively : 1.021 +/- 1.10(-3) g/ml for the lymphocytes, 1.024 +/- 2.5.10(-3) g/ml for the non eosinophil granulocytes, 1.025 +/- 2.5.10(-3) g/ml for the metamyelocytes, 1.030 +/- 3.5.10(-3) g/ml for the immature myeloid cells (myeloblasts, promyelocytes, myelocytes), 1.040 +/- 3.10(-3) g/ml for the eosinophil granulocytes, 1.055 +/- 10.10(-3) g/l for the megakaryocytes. The highest percentages of S phase cells, G2 and M phase cells determinated with a cytofluorograph correspond to peaks of immature myeloid cells (myeloblasts, promyelocytes and myelocytes). This method of bone marrow cells separation may be used to study the cell cycle in pathological bone marrows (leukaemia in particular) and to determine the effects and the efficiency of some antimitotics.

Bone Marrow Cells↗