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B Cassinat

Publications and source records attributed to B Cassinat.

16 recordsLinked to original sources
PubMed2001

In vitro all-trans retinoic acid sensitivity of acute promyelocytic leukemia blasts: a novel indicator of poor patient outcome.

Acute promyelocytic leukemia (APL) blasts possess a unique sensitivity to the differentiating effects of all-trans retinoic acid (ATRA). Multicenter trials confirm that the combination of differentiation and cytotoxic therapy prolongs survival in APL patients. However relapses still occur, and exquisite adaptation of therapy to prognostic factors is essential to aim at a possible cure of the disease. A heterogeneity was previously reported in the differentiation rate of patients' APL blasts, and it was postulated that this may reflect the in vivo heterogeneous outcome. In this study, it is demonstrated that patients of the APL93 trial whose leukemic cells achieved optimal differentiation with ATRA in vitro at diagnosis had a significantly improved event-free survival (P =.01) and lower relapse rate (P =.04). This analysis highlights the importance of the differentiation step in APL therapy and justifies ongoing studies aimed at identifying novel RA-differentiation enhancers.

Adult↗
PubMed2001

Sequence analysis identifies TTRAP, a protein that associates with CD40 and TNF receptor-associated factors, as a member of a superfamily of divalent cation-dependent phosphodiesterases.

CD40 is a member of the tumor necrosis factor (TNF) receptor family. CD40-mediated signal transduction involves the recruitment of several cytoplasmic proteins and induces expression of a large number of genes. TTRAP, a novel protein that interacts with the cytoplasmic domain of CD40 and with TNF-receptor associated factors (TRAFs), has been cloned and shown to inhibit nuclear factor-kappaB activation (NF-kappaB). By using various bioinformatics-based sequence and structure analyses of proteins involved in signaling by the TNF receptor family, we found that TTRAP is a member of a superfamily of Mg(2+)/Mn(2+)-dependent phosphodiesterases. More precisely, our results suggest that TTRAP is related to the human APE1, a Mg(2+)-dependent endonuclease. This potential novel function of TTRAP raises the intriguing possibility for a role of APE1-like DNA-repair endonucleases in TNF receptor family-mediated signaling and functions.

Amino Acid Motifs↗
PubMed2001

Future perspectives for acute promyelocytic leukemia therapy.

Acute promyelocytic leukemia (APL) is the first leukemia where targeted therapy proved to be effective, as only patients with retinoic acid-sensitive APL leukemic-clones responded in vivo. The future perspectives of APL therapy should persist in targeting either the APL's cell-specific characteristics concerning differentiation, cell cycle, and survival potentials, or the molecular markers specific to the APL clone. Converging recent advances in cellular therapy and in scientific concepts of cell differentiation should aim toward a possible cure of APL.

Antineoplastic Agents↗
PubMed2001

Variability in the levels of PML-RAR alpha fusion transcripts detected by the laboratories participating in an external quality control program using several reverse transcription polymerase chain reaction protocols.

BACKGROUND AND OBJECTIVES: The detection of PML-RAR by reverse transcription (RT) polymerase chain reaction (PCR) in acute promyelocytic leukemia (APL) patients who are in hematologic remission influences therapeutic decision making in several trials. In the light of this, the Spanish group has recently designed an external quality assessment program (EQAP) of RT-PCR detection of PML-RAR, which includes a study of sensitivity of the participating laboratories. DESIGN AND METHODS: Eighteen laboratories were involved in the program. Ten laboratories followed the method of Biondi et al., 5 employed that of Borrow et al. and the 3 remaining used other protocols. The sensitivity was studied in five rounds of quality control. The first two shipments consisted of dilutions of NB4 RNA into non-APL RNA. The third round consisted of serial dilutions of the NB4 cell line into HL60 cells. The fourth and five rounds consisted of plasmid dilutions containing the bcr1 and bcr3 PML-RAR isoforms. RESULTS: The results showed that the distinct methods allow detection of the PML-RAR hybrid up to a dilution of 10(-4), and exceptionally, up to 10(-5). The laboratories following the method of Biondi et al. usually detected the 10(-3) dilution and less frequently the 10(-4) one, whereas those using other methods usually detected PML-RAR transcript in the 10(-4) dilution, and less commonly in the 10(-5) dilution. However, each of the PCR methods used by EQAP participating laboratories successfully detected at least 50 copies of PML-RAR alpha fusion transcript in plasmid dilution controls. INTERPRETATION AND CONCLUSIONS: The results point to heterogeneous sensitivity amongst participating laboratories. This may reflect differences in methodology, although variations in sample quality may also account for discrepant findings.

Humans↗
PubMed2001

Intermethod discordance for alpha-fetoprotein measurements in Fanconi anemia.

BACKGROUND: The significantly higher serum alpha-fetoprotein (AFP) in patients with Fanconi anemia (FA) than in non-FA aplastic patients has potential diagnostic utility, but the increase is method-dependent. The aim of this study was to compare five AFP assays on FA and non-FA samples and to investigate possible explanations for FA-specific discrepancies. METHODS: Two methods available in our laboratory (Kryptor and IMx) were compared on 59 FA and 27 non-FA patient samples. Kryptor, Immulite, Elecsys, Immuno-I, and Elsa-2 methods were then compared on 14 FA and 14 non-FA patient samples. The AFP glycosylation profile was analyzed by electrophoretic separation in a lectin-containing gel. RESULTS: With all six methods, AFP values were significantly higher in FA than in non-FA patients, but the diagnostic precision and optimal cutoff values varied. Indeed, two methods reached 100% sensitivity and specificity, but in other methods, one or both of these parameters were significantly <100%. Neither heterophilic antibodies nor a specific glycosylation profile was detected in FA samples. CONCLUSIONS: AFP results are method-dependent in FA. New methods must be evaluated before use in differential diagnosis of aplastic patients.

Adolescent↗
PubMed2001

Is the thrombopoietin assay useful for differential diagnosis of thrombocytopenia? Analysis of a cohort of 160 patients with thrombocytopenia and defined platelet life span.

BACKGROUND: Thrombopoietin (TPO), the major hormone controlling platelet production, has been measured in thrombocytopenias with discordant results. The aim of our work was to assess the value of the TPO assay for differential diagnosis of thrombocytopenias in a large cohort of patients classified according to the results of their platelet isotopic study. METHODS: We measured TPO (R&D Systems) in serum of 160 thrombocytopenic patients referred to our department for platelet life span isotopic studies. We classified patients as follows: (a) idiopathic or autoimmune thrombocytopenia group (ITP; patients with increased platelet destruction and shortened platelet life span; n = 67); (b) pure genetic thrombocytopenia group (patients with decreased platelet production, normal platelet life span, and without bone marrow aplasia; n = 55); (c) bone marrow aplasia group (BM; patients with decreased platelet production, normal platelet life span, and bone marrow aplasia; n = 13). RESULTS: In patients with pure genetic thrombocytopenia, TPO (median, 55 ng/L) was not different from TPO in patients with ITP (median, 58 ng/L) or controls (n = 54; median, 51 ng/L). Only in patients with bone marrow aplasia was TPO significantly higher (median, 155 ng/L) and negatively correlated to the platelet count (r(2) = 0.5014). CONCLUSIONS: Although the median serum TPO is increased in thrombocytopenia with decreased platelet production from bone marrow aplasia, it does not differentiate patients with pure genetic thrombocytopenia from those with ITP.

Adolescent↗
PubMed2000

Constitutive elevation of serum alpha-fetoprotein in Fanconi anemia.

The diagnosis of Fanconi anemia (FA) is based on the association of congenital malformations, bone marrow failure syndrome, and hypersensitivity to chromosomal breaks induced by cross-linking agents. In the absence of typical features, the diagnosis is not easy to establish because there is no simple and cost-effective test; thus, investigators must rely on specialized analyses of chromosomal breaks. Because we observed elevated serum alpha-fetoprotein (sAFP) levels in FA patients, we investigated this parameter as a possible diagnostic tool. Serum AFP levels from 61 FA patients and 27 controls with acquired aplastic anemia or other inherited bone marrow failure syndromes were analyzed using a fluoroimmunoassay based on the TRACE technology. Serum AFP levels were significantly more elevated (P <.0001) in FA than in non-FA aplastic patients. In the detection of FA patients among patients with bone marrow failure syndromes, this assay had a sensitivity of 93% and a specificity of 100%. This elevation was not explained by liver abnormalities. Levels of sAFP were unchanged during at least 4 years of follow-up, and allogeneic bone marrow transplantation did not modify sAFP levels. Three of 4 FA patients with mosaicism as well as 5 of 6 FA patients with myelodysplastic syndrome were detected by this test. Heterozygous parents of FA patients had normal sAFP levels. Measurement of sAFP levels with this automated, cost-effective, and reproducible fluoroimmunoassay could be proposed for the preliminary diagnosis of FA whenever this disorder is suspected.

Adolescent↗
PubMed2000

Quantitation of minimal residual disease in acute promyelocytic leukemia patients with t(15;17) translocation using real-time RT-PCR.

We took advantage of a recently developed system allowing performance of real-time quantitation of polymerase chain reaction to develop a quantitative method of measurement of PML-RARalpha transcripts which are hallmarks of acute promyelocytic leukemia (APL) with t(15;17) translocation. Indeed, although quantitation of minimal residual disease has proved to be useful in predicting clinical outcome in other leukemias such as chronic myeloid leukemia or acute lymphoblastic leukemia, no quantitative data have been provided in the case of APL. We present here a method for quantitation of the most frequent subtypes of t(15;17) transcripts (namely bcr1 and bcr3). One specific forward primer is used for each subtype in order to keep amplicon length under 200 bp. The expression of PML-RARalpha transcripts is normalized using the housekeeping porphobilinogen deaminase (PBGD) gene. This technique allows detection of 10 copies of PML-RARalpha or PBGD plasmids, and quantitation was efficient up to 100 copies. One t(15;17)-positive NB4 cell could be detected among 106 HL60 cells, although quantitation was efficient up to one cell among 105. Repeatability and reproducibility of the method were satisfying as intra- and inter-assay variation coefficients were not higher than 15%. The efficiency of the method was finally tested in patient samples, showing a decrease of the PML-RARalpha copy number during therapy, and an increase at the time of relapse.

Chromosomes, Human, Pair 15↗
PubMed2000

Response.

Explore the source record for details and available documents.

Journal Article↗
PubMed2000

From guidelines to hospital practice: reducing inappropriate ordering of thyroid hormone and antibody tests.

OBJECTIVE: Because of major technical improvements and conscious care about cost effectiveness, limiting the inadequate use of thyroid biological tests appears to be a major issue. DESIGN: To (i) estimate the ordering prevalence of each thyroid test, (ii) assess the prevalence of relevant thyroid tests, and (iii) evaluate the impact of expressing justification for tests during a 2-month intervention period on these prevalences. METHODS: During a prospective 2-month survey (June-July 1997), all the request forms were divided into four groups of prescription: (1) investigation of thyroid function, (2) taking drugs affecting the thyroid, (3) monitoring of nodule and cancer, and (4) investigation of thyroid autoimmunity. Their appropriateness was thus determined according to consensus in our hospital and previously published recommendations. Results were compared with those of retrospective similar 2-month periods in 1996 and 1998. Combinations of thyroid function tests and thyroid antibodies were analyzed during the 1996, 1997 and 1998 periods. RESULTS: The overall estimated rate of appropriate ordering between 1996 and 1997 increased from 42.5% to 72.4% (P<10(-4)), with a significant improvement in each group of main diagnosis referral, except in group 3 where suitability was always over 85%. However, in group 4, appropriateness remained low (36%). Combinations of thyroid tests revealed an increase in single TSH order forms and single autoantibodies to thyroperoxidase (TPOAb) ones, while TSH+free thyroxine+free tri-iodothyronine and TPOAb+ autoantibodies to thyroglobulin ones decreased significantly. Interestingly, all these changes were maintained 1 year later (June-July 1998) even though physicians were not aware of this new study. CONCLUSIONS: Persistent change in medical practice was thus assessed.

Autoantibodies↗
PubMed1997

Co-expression and secretion of C3, the third component of complement and a C3-cleaving cysteine proteinase in a highly metastatic human melanoma cell line.

We recently demonstrated that DM-4, a human melanoma cell line highly metastatic in nude mice, expressed a p41 C3-cleaving proteinase. This p41 proteinase is a cysteine proteinase, associated to cell surface and involved in tumorigenicity and metastatic properties of these tumor cells. We demonstrate herein that DM-4 cells also secrete the p41 proteinase. In addition, analysis of cellular components which reacted with the p41 proteinase led us to demonstrate that DM-4 cells synthesized and secreted human C3. Secreted C3 is cleaved by the secreted p41 proteinase and a C3dg-like fragment is generated. This is the first demonstration that a human melanoma cell line co-expresses and co-secretes human C3 and a C3-cleaving cysteine proteinase, antigenically related to procathepsin L.

Animals↗
PubMed1995

Epstein-Barr virus/C3d receptor (CR2, CD21) activated by its extracellular ligands regulates pp105 phosphorylation through two distinct pathways.

We previously demonstrated that human C3d or pep16, a 16-amino acid synthetic peptide derived from human C3d, induced in vivo and in vitro tyrosine phosphorylation of pp105, an intracellular component found only in human cells that express CR2 at their surface. To determine the contribution of CR2 molecules to this enzymatic regulation, we first analyzed whether activation of CR2 by other extracellular CR2 ligands could trigger such regulation in cell extracts. Subsequently, we used cell extracts of either CR2-positive cells depleted in CR2 molecules by absorption with anti-CR2 antibodies or CR2-negative cells transfected with CR2 cDNA. We demonstrate here that pp105 phosphorylation was induced when CR2 was activated by C3d and pep16 as well as by gp350, the Epstein-Barr virus capsid protein or OKB7, an anti-CR2 monoclonal antibody (mAb). HB5, another anti-CR2 mAb, which did not activate B lymphocytes through CR2, did not induce pp105 phosphorylation. Thus, C3d, pep16, gp350, and OKB7 presented similar properties in activating CR2 to trigger pp105 phosphorylation and in regulating B lymphocyte proliferation, while HB-5 had no effect on either assays. Furthermore, our data demonstrate that the presence of CR2 activated by its extracellular ligands regulates pp105 phosphorylation through two distinct pathways: one which also requires the presence of non-activated CD19, and one which is independent of CD19. The involvement of CD19 in the first pathway was not due to the formation of putative CR2-CD19 complexes. Both pathways were TAPA-1 independent. This is the first demonstration that activated CR2 molecules can play a regulatory role in enzymatic function, such as phosphorylation, despite the absence of CD19 and TAPA-1.

B-Lymphocytes↗
PubMed1995

Pep34, a synthetic peptide whose sequence corresponds to the intracytoplasmic domain of the Epstein-Barr virus receptor (CR2, CD21), regulates human B lymphocyte proliferation triggered through CR2.

CR2 is involved in regulation of human B lymphocyte proliferation by interacting, through distinct domains, with extracellular, cell surface or intracellular components. Contribution of CR2 intracytoplasmic domain in CR2 regulatory functions remains unclear. Thus, we used pep34, a 34 amino acid synthetic peptide whose sequence corresponds to CR2 intracytoplasmic domain. Pep34 was incorporated into B lymphocytes which were then activated by EBV or C3d through CR2. Our data demonstrate that pep34 inhibits 100% B lymphocyte proliferation triggered by EBV or C3d. Irrelevant peptide had no effect. When B lymphocyte proliferation was triggered by a multipotent B cell activator as SAC, pep34 did not exert any inhibitory effect. Our data demonstrate that pep34 inhibits B lymphocyte proliferation only when lymphocytes are triggered through CR2. Thus, this strongly supports that despite its short length. CR2 intracytoplasmic domain participates to regulatory functions of this receptor.

Amino Acid Sequence↗
PubMed1994

Comparison of antibiotic combinations against penicillin-resistant pneumococci.

The isolation rate of penicillin resistant pneumococci is increasing in France. To date, cefotaxime and ceftriaxone are the two drugs recommended for the treatment of severe infections and oral third generation cephalosporins are frequently employed for the treatment of non-invasive pneumococcal diseases. In this study, we determined the bacteriostatic activity of 21 antibiotic combinations against 13 clinical isolates of Streptococcus pneumoniae with MICs > or = 0.1 mg/L penicillin and 13 strains that were susceptible.

Anti-Bacterial Agents↗
PubMedDate not supplied

Evaluation of total PSA assay on vitros ECi and correlation with Kryptor-PSA assay.

BACKGROUND: An increasing number of multiparametric immuno-analysers for PSA assays are available. As different immuno-assays may vary in their analytical quality and their accuracy for the follow-up of patients, expertise is necessary for each new assay. METHODS: The PSA assay on the Vitros-ECi analyser has been evaluated and compared with the PSA assay from the Kryptor analyser. RESULTS: Variation coefficients were 0.91 to 1.98% for within-run assays, and 4.2% to 5.4% for interassay (PSA levels = 0.8 microgram/L to 33.6 micrograms/L). Dilution tests showed 93 to 136% recovery until 70 micrograms/L PSA. Functional sensitivity was estimated at 0.03 microgram/L. Equimolarity of the test was confirmed. Correlation of PSA levels measured with Vitros-ECi and Kryptor analysers displayed a correlation coefficient r2 of 0.9716. The half-lives and doubling times of PSA were similar using both methods. CONCLUSION: Vitros-ECi PSA assay meets the major criteria for the management of prostate cancer patients.

Adenocarcinoma↗