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Biomedical subjects

A Cosson

Publications and source records attributed to A Cosson.

At least 55 records · Page 3Linked to original sources
PubMed1995

Good predictive value of combined cytogenetic and molecular follow up in chronic myelogenous leukemia after non T-cell depleted allogeneic bone marrow transplantation: a report on 38 consecutive cases.

We prospectively performed repeated cytogenetic and PCR monitoring of residual disease in all cases Ph positive of chronic myeloid leukemia (CML) allografted with non T cell depleted marrow at our institution over a period of 8 years. Thirty eight patients who survived the immediate post transplant period could be analyzed (median of 3 cytogenetic analyses/patient, examining 100 mitoses, and 4 PCR analyses/patient). Seven of the 38 patients had a hematological relapse (which was extramedullary in one case) and one a purely cytogenetic relapse, possibly stabilised by interferon treatment. Within 6 months of transplant, Ph positive mitoses were seen in 2 patients, and positive PCR in most cases, without implying subsequent relapse. Six of the 32 patients analyzed cytogenetically more than 6 months post transplant had Ph positive mitoses on at least one occasion: 5 had a hematological relapse within 7 months of positive cytogenetic analysis, and the remaining patient, treated by interferon remained in purely cytogenetic relapse. (The extramedullary relapse was not preceded by a positive marrow karyotype). Eight of the 38 patients had positive PCR findings on at least one occasion more than 6 months post transplant. Seven relapsed (6 hematological relapses including the extramedullary relapse, and 1 cytogenetic relapse) after 3 to 20 months, but the remaining patient remained in CR 36 months later, with negative PCR. The 30 patients who never had positive PCR findings remained in CR. In this relatively large series of patients, we found a good correlation between PCR findings more than 6 months post transplant and remission or relapse status.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1995

The retinoblastoma gene (RB-1) status in multiple myeloma: a report on 35 cases.

We looked for abnormalities of the retinoblastoma (RB-1) gene and of RB protein expression in 35 patients with multiple myeloma (MM). Mutations in exons 20 to 24 of the RB-1 gene (exons where mutations predominate in retinoblastoma and other solid tumors) were analyzed by single stranded conformation polymorphism (SSCP). RB-1 protein was studied in bone marrow plasma cells by immunocytochemistry (ABC peroxidase technique) with a specific monoclonal antibody. Southern blot analysis of RB-1 gene was also performed in 20 of the patients. Twenty two patients analyzed had advanced disease (stage III or, in one case, plasma cell leukemia) and cytogenetic analysis (performed in 31 cases) found monosomy 13 in 9 patients. No rearrangement of the RB-1 gene was found by Southern analysis. Absent or greatly reduced RB-1 protein level was found in plasma cells in 4 of the patients (11%), whereas normal levels were seen in the remaining cases. No point mutation in exons 20 to 24 and their flanking introns were found in any of the 35 patients. Three of the 4 patients with absent or reduced RB-1 protein expression had advanced MM (stage III: 2 cases; plasma cell leukemia: 1 case); all 4 patients were resistant to treatment (as compared to 7 of the 31 patients with normal RB-1 protein levels); only one of them was subsequently found to have monosomy 13 (as compared to 9 of the 28 other karyotyped patients). Our findings suggest that abnormalities of the RB-1 gene and its expression are rare in MM. Absent or reduced expression of RB-1 protein was not significantly correlated to monosomy 13 and was not associated with gross rearrangements of the RB-1 gene by Southern analysis or point mutations in exons 20 to 24 of the gene. Reduced expression of RB-1 protein may be associated with advanced disease and poor response to treatment, although larger numbers of patients will be required for more adequate conclusions.

Base Sequence↗
PubMed1995

bcl-2 expression in myelodysplastic syndromes and its correlation with hematological features, p53 mutations and prognosis.

We looked for bcl-2 protein expression by immunocytochemistry on bone marrow slides from 51 cases of myelodysplastic syndrome (MDS), of whom 25 received some form of chemotherapy. Forty-six of them had at least 20% bcl-2 positive blasts and the median percentage of positive blasts was 80%, whereas myeloid cells beyond blasts were always negative. No correlation was found between bcl-2 expression and the FAB type of MDS, CD34 expression and P-glycoprotein expression. A strong correlation between weak bcl-2 expression and the presence of a p53 mutation detected by SSCP analysis and direct sequencing was found. Response to chemotherapy (intensive chemotherapy or low-dose Ara-C) and survival were not significantly influenced by the intensity of bcl-2 expression in blasts, although there was a trend for better response to chemotherapy and longer survival in patients with strong bcl-2 expression. This trend was no longer found, however, if patients with a p53 mutation were excluded. Our findings show that blasts from a majority of MDS cases have bcl-2 expression and that strong bcl-2 expression is not associated with a poor prognosis. The correlation between weak bcl-2 expression and p53 mutation suggests a possible downregulation of bcl-2 gene expression by mutated p53, the mechanism of which remains to be established.

Gene Expression↗
PubMed1995

Cross-reactive immunity against different strains of the hepatitis E virus transferable by simian and human sera.

Monkey infection with the hepatitis E virus induces protection. We confirm the humoral nature of this immunity and show that protection is effective against the homologous strain, as well as against heterologous strains isolated from Asian and African countries. However this immunity is incomplete since only the clinical disease seems to be prevented, while the virus is still excreted in stools and can even appear in blood as well after serotherapy as previous acute or occult infections. We obtained also a preliminary evidence that convalescent human sera are also efficient for the passive protection, indicating that seroprophylaxis of HEV hepatitis in pregnant women (20% of mortality during the 3rd trimester of pregnancy) should be attempted in the case of epidemics.

Animals↗
PubMed1994

Immunoglobulin and T-cell receptor delta gene rearrangements are rarely found in myelodysplastic syndromes in chronic phase.

Clonality, in MDS, can only be assessed in patients with chromosomal rearrangements or in females heterozygote for X chromosome restricted polymorphisms. "Illegitimate" rearrangements of the immunoglobulin heavy chain (IgH) gene and incomplete rearrangements involving V delta 2 and D delta 3 segments of the T-cell receptor delta (TcR delta) gene are seen in some cases of AML, and AML post-SMD, and can be detected by a sensitive PCR method. In order to analyse clonality in additional cases in MDS, we looked for Ig H and TcR delta gene rearrangement by PCR in 95 cases of MDS. A rearrangement of the Ig H gene was seen in 2 of the 95 patients: in the circulating blood of 2 of the 36 cases of chronic myelomonocytic leukaemia (CMML) and in none of the marrow samples of the other 59 MDS. A rearrangement of the TcR delta gene (involving V delta 2 and D delta 3 segments) was seen in three cases (in the circulating blood of two other CMLL patients, and in the bone marrow of another MDS patient). Twenty-five of the 90 cases of MDS with negative PCR findings, in addition to the five cases with positive PCR findings underwent Southern blot analysis of Ig H and TcR delta genes, and PCR analysis of V delta 1 and J delta 1 segments of the TcR delta gene. Those examinations were normal in all the cases tested. In patients with positive PCR findings for Ig H or V delta 2 D delta 3 rearrangements, the proportion of rearranged cells was evaluated at 1-5% in four cases, and 5-10% in the remaining patient. Because the analysis was performed on total circulating leukocytes or total nucleated marrow cells, the nature of the clonal population in positive cases (lymphoid cells? myeloid cells? blasts?) could not be determined. From a practical point of view, Ig H and TcR delta gene rearrangements seem to very rare in MDS, and cannot be used as clonality markers in most cases.

Anemia, Refractory↗
PubMed1994

Image analysis in multiple myeloma at diagnosis. Correlation with cytogenetic study.

The DNA content of plasma cells (DNA Index or DI) was determined after Feulgen reaction using computed image analysis in 46 patients with multiple myeloma at diagnosis. Aneuploidy was found in 40/46 (87.0%) patients; 27 (58.7%) were hyperdiploid (DI = 1.05-1.45), 11 (24.0%) were hypodiploid (DI = 0.90-0.95), and two (4.3%) were biclonal. Cytogenetic study showed at least one abnormal mitosis in 21/46 (45.7%) cases. All patients with numeric changes had aneuploid DI, and thus confirmed DI > or = 1.05 and DI < or = 0.95 as good limits for aneuploidy with image analysis. Since abnormal karyotypes were observed mainly in stages II and III (55.6% and 54.5%, respectively) rather than in stage I (26.7%), aneuploid DI was found in most patients in all three stages, namely in all 15/15 (100%) patients in stage I. The prognostic value of aneuploidy was difficult to ascertain in our series. Hypodiploidy or DI > 1.15 was not especially associated with aggressive disease, as it was observed in 7/15 patients in stage I; however, with the same limits, patients with stages II and III were refractory to first-line chemotherapy. Image analysis is a highly sensitive method showing aneuploidy in most patients with MM at diagnosis and, in association with cytogenetic study, may help to better understand the pathogenesis of the disease. The independent prognostic value of aneuploidy was not fully established in this report.

Aneuploidy↗
PubMed1994

Inactivation of the retinoblastoma gene appears to be very uncommon in myelodysplastic syndromes.

Rearrangements of the retinoblastoma (RB) gene have been reported in a few cases of myelodysplastic syndromes (MDS). In addition, low or absent expression of the RB protein is found in 20-30% of cases of acute myeloid leukaemias (AML), particularly in AML with a monocytic component (M4 or M5). We performed Southern blot analysis of the RB gene in 90 cases of MDS, including 37 cases of chronic myelomonocytic leukaemia (CMML). None of them had progressed to AML at the time of study. In 37/90 patients (including 20 CMML) Northern blot analysis, study of RB protein by immunocytochemistry on bone marrow slides, and detection of point mutations in exons 20-24 of the RB gene was also made, using single strand conformation polymorphism analysis (SSCP). No abnormal Southern profile was found in any of the 90 patients. Northern blot and immunocytochemical study of RB protein were normal in the 37 cases studied. SSCP analysis detected a point mutation in 2/37 patients tested. Direct sequencing confirmed the mutation in each case, which involved intron 21 and intron 23, respectively, and was located outside splicing sites of the neighbouring exons. These findings suggest that abnormalities of the RB gene and its expression must be very rare in MDS, and play a minor role, if any, in the pathophysiology of those disorders, at least before progression to AML.

Base Sequence↗
PubMed1994

Evidence for time-dependent activation of monocytes in the systemic circulation in unstable angina but not in acute myocardial infarction or in stable angina.

BACKGROUND: Platelet activation plays a pivotal role in the pathogenesis of acute coronary disease. Monocytes are involved in the progression of atherosclerosis and are potent activators of blood coagulation through their ability to synthesize tissue factor (TF). The aim of this study was to compare markers of monocyte and coagulation activation in the systemic blood of patients with unstable angina, acute myocardial infarction, or stable angina. METHODS AND RESULTS: We studied 26 patients with unstable angina (10 +/- 5 hours after the onset of the last episode of pain), 18 patients with acute myocardial infarction (5 +/- 4 hours after the onset of pain), and 34 patients with stable angina. We measured levels of TF expression in peripheral blood mononuclear cells (isolated by gradient centrifugation and incubated for 16 hours, with or without endotoxin stimulation), levels of plasma prothrombin fragment 1 + 2 (F1 + 2), and levels of fibrinogen in peripheral blood. In patients with unstable angina, both stimulated and unstimulated cells exhibited higher levels of TF expression than in patients with stable angina (P = .0001). In patients with acute myocardial infarction, monocyte TF activity did not differ from that in patients with stable angina. Mean levels of F1 + 2 and of fibrinogen did not differ significantly between groups. Only in the unstable angina group, a modest correlation was found between fibrinogen (r = .72, P = .005) and F1 + 2 levels (r = .54, P = .001) levels and the degree of monocyte TF expression. In patients with unstable angina, monocyte TF expression (both stimulated and unstimulated, assessed by biological activity and by antigen techniques) and fibrinogen levels were correlated with the time elapsed from the beginning of the most recent episode of pain (.61 < r < .72, .02 < P < .0001). By contrast, there was no correlation between these variables and the time from onset of pain in patients with acute myocardial infarction. CONCLUSIONS: A time-dependent activation of systemic monocytes and a time-dependent increase in fibrinogen levels occurs in unstable angina but not in myocardial infarction. These findings provide further evidence that a specific inflammatory process occurs in unstable angina. Further studies are required to determine whether monocyte activation is a cause or a consequence of plaque instability in patients with unstable angina and to clarify the interrelations between platelet and monocyte activation in these circumstances.

Adult↗
PubMed1994

Significance of circulating plasma cells in multiple myeloma.

The number of circulating plasma cells (CPC) was determined on mononuclear cell preparations after Giemsa (morphology) and light chain staining (immunocytochemistry). Both methods gave reproducible and identical results when CPC were 1% or more. Using this limit, no CPC were observed in MGUS (0/11) and primary amyloidosis (0/2), whereas 45/98 (45.9%) multiple myeloma (MM) pts had > or = 1% CPC. 3/14 pts (21.4%) in stage I, 5/13 pts (38.5%) in stage II, 20/28 pts (71.4%) in stage III, 4/25 pts (16%) at plateau phase, and 13/18 pts (72.2%) at relapse had > or = 1% CPC (p < 0.001). Mean beta-2 microglobulin was 3.77 mg/l and 6.08 mg/l for pts without or with > or = 1% CPC, respectively p = 0.0001). Presence of CPC was also correlated with an higher percentage of bone marrow PC, but not with the number of Ki-67 positive BM-PC, and not with CRP or LDH levels. K/L and Gamma/Alpha CPC isotype ratio showed these cells as monotypic in nearly all pts. The prognostic value could not really be assessed in this study, as only the initial response to therapy was investigated, and the latter failed to give any difference between pts with and without CPC. So, presence of CPC is not an infrequent finding, but is highly related to tumor mass and active disease; in most if not all patients they are monotypic and certainly belong to the malignant clone. Their prognostic value is unclear but under current investigation; CPC are correlated with B-2M level.

Cell Count↗
PubMed1994

Expression of the multidrug resistance P-glycoprotein and its relationship to hematological characteristics and response to treatment in myelodysplastic syndromes.

Expression of P-glycoprotein (PGP), the product of the multi-drug resistance mdr1 gene was studied by immunocytochemistry on bone marrow slides using JSB1 monoclonal antibody and the alkaline phosphatase-antialkaline phosphatase (APAAP) and avidin-biotin-peroxidase (ABC) techniques in 82 cases of untreated myelodysplastic syndromes (MDS), of whom ten had evolved to AML (MDS-AML). The relationship between PGP expression, myeloperoxidase activity and immunophenotype of blast cells, karyotype and outcome was also analyzed. PGP expression was found in the blasts of 34 of the 82 patients (41%), the majority of blasts being stained in positive cases. PGP positivity was rare in 'low risk' MDS (RA and RARS: 2/12 cases) as opposed to 'high risk' MDS (RAEB, RAEB-T, CMML: 25/60 cases) and MDS-AML (7/10 cases) (p = 0.04). PGP expression was positively correlated to the presence of myeloperoxidase activity in less than 3% of blasts (p = 0.025), and CD34 antigen expression (p = 0.04), whereas CD33 antigen expression had borderline significance (p = 0.07), demonstrating that PGP expression predominated in blasts with an immature phenotype. An abnormal karyotype, and especially the presence of monosomy 7, was not correlated to a higher incidence of PGP expression, however. There was a trend for more frequent progression to AML and for shorter survival in PGP-positive cases, but differences with PGP-negative cases were not significant. Twenty patients received intensive anthracycline-Ara-C chemotherapy and ten (50%) achieved complete response, including 9/13 (69%) PGP-negative cases and 1/7 (14%) PGP-positive cases (p = 0.03). Twenty other patients were treated with low-dose Ara-C and ten (50%) responded (complete or partial response). PGP-positivity did not negatively affect response to low-dose Ara-C: 4/11 responses in PGP-negative, and 6/9 responses in PGP-positive patients (p = 0.18). Because the treatment choice in advanced MDS (especially between anthracycline-Ara-C or low-dose Ara-C, chemotherapy) is difficult, our preliminary therapeutic results suggest that the analysis of PGP expression could have practical importance in MDS. These findings however, will have to be confirmed on larger numbers of patients. Clinical trials using drugs potentially reverting mdr, activity could also be warranted in MDS.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1994

[Evaluation of Abbott CD 3500 in severe leukopenia].

Leucopenia patient follow-up remains, in terms of laboratory turnaround, a heavy workload due to the leucoconcentrations necessary for evaluating leucocytic formulas. We tested the CD 3500 with the objective of defining its' analytical performances and routine practice. 101 leucopenia samples (< 2.10(9)/l) procured from the onco-hematology department (adults and children) were studied during a 1 month period. The leucocytic formula obtained after leuconcentrations was our reference. The alarm sensitivity, as a whole, was of 97% for a 15.5% specificity. The correlation coefficients (Cell-Dyn/microscope) for polynuclears, lymphocytes and monocytes were respectively 0.889, 0.925 and 0.926. The correlation coefficients observed in both following subgroups: < or = 0.5.10(9)/l and > 0.5.10(9)/l were superposable. In 95% of the cases, the numeric value difference between the two methods attained a maximum of 21% for all neutrophils and lymphocytes and 13% for the monocytes. There was an excellent concordance between both methods for eosinophilia and basophils with confidence intervals of +/-8.8% and +/-2.2%. In practice, we feel that the use of a CD 3500 in post chemotherapy leucopenia, is perfectly adaptable and appreciated for leucocytic formulas, as well as a good exit for aplasia.

Autoanalysis↗
PubMed1994

Detection of p53 mutations in hematological malignancies: comparison between immunocytochemistry and DNA analysis.

The wild type p53 protein has a short half-life and cannot be detected by immunohistochemistry on tissue sections. Mutated p53, on the other hand, has a prolonged half-life and becomes detectable by this method, so that its detection by immunohistochemistry in solid tumors is almost synonymous with mutation. We assessed the value of immunocytochemical analysis of p53 protein on blood or bone marrow slides in the detection of p53 mutation in hematological malignancies, by comparison with single-stranded conformation polymorphism (SSCP) analysis of exons 4 to 10 of the P53 gene. One hundred and twenty eight patients with acute myeloid leukemia (AML), acute lymphoid leukemia (ALL), myelodysplastic syndromes (MDS), or chronic lymphocytic leukemia (CLL) were studied by both methods. Immunocytochemistry showed detectable levels of intracellular p53 in 19 cases (including 2/19 AML, 2/21 ALL, 11/48 MDS, 4/40 CLL). Staining by p53 antibodies was restricted to the nucleus of blasts in AML, ALL, and MDS, and of lymphocytes in CLL. In 16 of the 19 cases, SSCP analysis, followed by direct sequencing, showed a p53 missense mutation in exons 4 to 8 of the gene. In the remaining three cases, where the number of cells stained by p53 antibodies was small, no p53 mutation could be detected. On the other hand, SSCP and sequence analysis identified a p53 mutation in two patients who had negative immunocytochemical findings. Both cases had a nonsense mutation, presumably leading to reduced levels of truncated p53. Thus, overall, immunocytochemistry and SSCP gave concordant results in 123 of the 128 (96%) patients analyzed. Our findings show that immunocytochemistry on blood and bone marrow smears is a sensitive method of p53 mutation detection in hematological malignancies, except in the rare patients with chain-terminating mutations. Positive immunocytochemistry is found in some patients with normal SSCP findings, and could correspond to overexpression of a non-mutated p53, but also to p53 mutation in a minor proportion of the malignant cells, undetectable by SSCP.

Anemia↗
PubMed1993

Immunological detection of myeloperoxidase in poorly differentiated acute leukemia.

We performed immunocytochemical detection of myeloperoxidase (MPO), using monoclonal antibody MPO-7, in 15 consecutive cases of adult acute leukemia (AL) unclassified by conventional cytological and cytochemical criteria and 7 AML-M1 with less than 10% of cytochemically MPO-positive blasts. In AL with negative MPO cytochemistry the anti-MPO reaction was positive in 5 of the 15 patients with 3, 3, 7, 11 and 45% positive blasts respectively. In AML-M1, immunocytochemistry was positive in a larger percentage of blasts than cytochemistry in 2 cases. Immunological detection of myeloid surface markers was positive in all 15 cases of unclassified AL (including the 10 AL with negative anti-MPO reaction). Eleven of the 22 patients from this study had mixed lymphoid-myeloid phenotype. Discrepancy between immunological MPO detection and light cytochemistry was more frequent in patients with mixed immunophenotype than in patients without lymphoid markers. No relationship between MPO-antigen positivity and clinical or biological features was seen. These findings confirm immunological detection of MPO as useful for the diagnosis of poorly differentiated AL. The high incidence of inactive MPO detectable only by immunocytochemistry in mixed lineage AL needs to be confirmed.

Acute Disease↗
PubMed1993

Relationship between p53 gene mutations and multidrug resistance (mdr1) gene expression in myelodysplastic syndromes.

P glycoprotein, the product of multidrug resistance (mdr1) gene, is frequently expressed in advanced myelodysplastic syndromes (MDS) with an excess of bone marrow blasts and could explain their frequent resistance to chemotherapy. P53 gene mutations are also found in 10 to 15% of advanced MDS. Because it has recently been suggested that normal p53 suppressed, but that mutated p53 activated, the mdr1 gene promoter, we tried to correlate p53 mutations and P glycoprotein expression in 34 patients with MDS and an excess of bone marrow blasts (> 5%). P glycoprotein expression was assessed by immunocytochemistry using JSB1 monoclonal antibody and was found positive in 13 out of the 34 patients. p53 mutations were detected both by immunocytochemistry using three different monoclonal antibodies and by single stranded conformation polymorphism (SSCP) analysis of exons 5 to 8 of the P53 gene. Both methods detected a point mutation in 5 out of the 34 patients. Only one out of the 5 patients with a p53 mutation expressed P glycoprotein, as compared to 12 out of the 29 patients without p53 mutations. This suggested the mutant and normal p53 are not major determinants of the regulation of mdr1 expression in vivo, at least in MDS.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1993

Philadelphia negative, BCR-ABL positive adult acute lymphoblastic leukemia (ALL) in 2 of 39 patients with combined cytogenetic and molecular analysis.

We performed cytogenetic and molecular analysis of the BCR-ABL rearrangement by polymerase chain reaction (PCR) in 39 consecutive cases of adult acute lymphoblastic leukemia (ALL). Eleven patients had a Philadelphia (Ph) chromosome. Thirteen patients had a BCR-ABL rearrangement, involving minor breakpoint cluster region (m-bcr, situated in intron 1 of the BCR gene) in 11 cases, and major breakpoint cluster region (M-bcr, 'specific' of chronic myeloid leukemia) in the remaining two cases. All of the 12 BCR-ABL cases studied immunologically were of early B, CALLA-positive immunophenotype. The 13 BCR-ABL positive cases included the 11 Ph-positive cases, and two patients with normal karyotype at diagnosis. In the two Ph-negative BCR-positive cases, seven (patient 1) and 18 (patient 2) mitoses had been examined at diagnosis. In patient 1, Ph negativity at diagnosis could certainly be explained by the small number of mitoses analyzed, as a Ph chromosome was found at relapse. This was less probable in patient 2, who raised the issue of whether authentic Ph-negative BCR-ABL-positive ALL exists (as in the chronic myeloid leukemia model) or not. Whatever the explanation, our results suggest that molecular detection of BCR-ABL should be more widely used in B-lineage ALL.

Adult↗