Biomedical subjects
Publications and source records attributed to F Sigaux.
The authors consider the clinical and biological data of Acquired Idiopathic Sideroblastic Anemia (AISA). The physiopathology of the syndrome is discussed; the relationships between pathologic sideroblastosis, dyserythropoiesis and ferrokinetic modifications are pointed out. The associated abnormalities of granulocytic and megacaryocytic series linked AISA to other myelodysplasia.
We have compared different methods for the assay of unsaturated B12 binding capacity of the whole serum and of each of the three transcobalamins (TC I - TC II - TC III). This comparison was important to check the conditions of reproducibility of each method; moreover it has led us to arrive at some modifications to resolve the larger fraction (TC I + TC III) into two distinct components.
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Despite modern regimen of chemotherapy, one-third of children with acute lymphoblastic leukaemia relapse. Recent studies have shown that a high level of minimal residual disease (MRD) at the end of induction is associated with an increased risk of relapse. We have developed and validated a real-time PCR method (RQ-PCR) to quantify MRD. We monitored 57 patients using IgH and TCR (Vdelta2Ddelta3) genes rearrangements as PCR targets. RQ-PCR was performed with a primer and a TaqMan probe designed to consensus sequences in VH segments in combination with one allele specific oligonucleotide primer complementary to the junctionnal region. A sensitivity of 10(-4) was reached for 72% of the IgH alleles (n = 50) and for 54,5% of the Vdelta2Ddelta3 alleles (n = 22). We compared the results with those obtained by competitive PCR in 53 patients: no discordance between the two methods was observed. Seventeen patients were found positive (32%) and 27 negative (51%) with both techniques and 9 children (17%) were positive only with TaqMan technology. RQ-PCR is more sensitive and more specific than competitive PCR. We thus propose that RQ-PCR might be used in first intention for MRD analysis.
The effect of in vivo administered interferon-alpha (IFN-alpha) on 2-5-oligoadenylate (A) synthetase activity of peripheral blood mononuclear cells (PBMC) was compared in patients with hairy cell leukemia and renal cell cancer. Basic levels of this enzyme varied from donor to donor, but mean levels were not significantly different in patients with renal cell cancer or hairy cell leukemia compared to healthy donors. After a single injection of 3 x 10(6) IU IFN, these basic levels rose 2- to 8-fold within 12-24 h post-injection and reverted to pretreatment levels after 48 h. The extent of this in vivo stimulation by IFN-alpha was similar in patients with hairy cell leukemia and renal cell carcinoma, and was correlated with down-regulation of IFN-alpha receptors. The in vitro effects of IFN-alpha, -beta and -gamma were compared after 18 h treatment with 10, 10(2) and 10(3) IU/ml of each IFN. Unlike IFN-alpha and -beta, IFN-gamma did not induce 2-5 A synthetase activity in either normal PBMC or hairy cells; these results were related to the effects of the three IFN on proliferative response of normal PBMC to phytohemagglutinin. Our data support the idea that 2-5 A synthetase activity is a marker of biological response to interferon treatment in human cancers.
The authors consider the clinical and biological data of Acquired Idiopathic Sideroblastic Anemia (AISA). The physiopathology of the syndrome is discussed; the relationships between pathologic sideroblastosis, dyserythropoiesis and ferrokinetic modifications are pointed out. The associated abnormalities of granulocytic and megacaryocytic series linked AISA to other myelodysplasia.