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Biomedical subjects

R Fauchet

Publications and source records attributed to R Fauchet.

At least 91 records · Page 5Linked to original sources
PubMed1990

HLA class I gene polymorphism in genetic hemochromatosis.

The authors have studied HLA class I polymorphism in an attempt to identify a genomic marker of the hemochromatosis gene. Five enzymes were used (HindIII, EcoRI, EcoRV, PvuII, and HincII) in 47-106 unrelated patients and 71-91 controls. Both populations were HLA-typed. The relationship between the restriction fragments and HLA-A antigens was considered. Comparison of the two groups revealed a significantly high frequency of one 14 kb EcoRI fragment among the HLA-A3 hemochromatosis patients. The fragment hybridizes to an HLA-A specific probe but not to an HLA-B specific probe, and is associated with the hemochromatosis gene, which is itself associated with HLA-A3.

HLA Antigens↗
PubMed1990

Implication of the HLA-DRB3 gene in Graves' disease: predominance of allele Dw24.

Using RFLP, the present study sets off to determine the MHC class II gene polymorphism in Graves' disease, in order to define the HLA-related genetic susceptibility. Considering the preferential link between Graves' disease and the HLA-DR3 antigen, 42 HLA-DR3 Graves' disease patients were studied and compared with 42 HLA-DR-matched controls. Hybridization with a DQ alpha probe of DNAs digested by Taq I revealed a polymorphism of the DR3 haplotype with an overrepresentation of a 2.1 kb(U) fragment in patients, but this was merely a sign of the linkage disequilibrium between U and B8DR3. Hybridization with the DR beta probe of DNAs digested by Taq I yielded more facts. It revealed the overrepresentation of the Dw24 specificity (Taq I:9.8 kb) in DR3 Graves' disease patients. This study thus enabled us to determine precisely the susceptibility linked to the DR3 haplotype, implicating the DRB3 gene and its Dw24 allele, which appear to be the most reliable markers of the disease, providing a higher relative risk than B8DR3.

Alleles↗
PubMed1990

Antithyroid drugs and Graves' disease: a prospective randomized evaluation of the efficacy of treatment duration.

A prospective randomized study was performed in patients with hyperthyroid Graves' disease (GD) in order to compare long (18 months) and short term (6 months) antithyroid drug treatment on the remission rate. A therapeutic protocol was offered to all GD patients who had not been treated for this disease previously. All patients studied who followed the protocol were rechecked 2 yr after treatment was withdrawn, or earlier in the case of relapse. Of the patients having undergone long term treatment, 61.8% still were in remission 2 yr after treatment withdrawal, whereas only 41.7% of the patients treated for 6 months were in remission (P less than 0.05). Such findings clearly establish that treatment duration has a direct beneficial incidence on the remission rate. These results were confirmed by the fact that treatment for 18 months resulted in remission in 7 of 15 patients who had previously relapsed after a 6-month course of therapy. This improvement in relation to treatment duration might be due to the immunosuppressive action of carbimazole. No significant difference was observed between relapse and remission groups, regardless of treatment duration, for HLA ABDr, serum T3 and T4, and T3/T4 ratio determined before treatment. Only the thyroid-stimulating antibody levels determined at the time of diagnosis and at the end of treatment were higher in the relapse group, a difference that was relevant only globally, due to value scattering. Furthermore, thyroid-stimulating antibody levels at the end of treatment may indicate remission or, conversely, continuance of the pathological process.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1989

Presence on a human melanoma of multiple antigens recognized by autologous CTL.

We derived from blood lymphocytes of a melanoma patient a large number of cytolytic T-cell clones directed against a cell line of the autologous tumor. Three distinct groups of antigens were recognized by these CTL on the autologous melanoma cells: group A consisted of stable antigens present on all sublines, whereas antigens B and C appeared unstable and were expressed by distinct sublines. In vitro immunoselections with various anti-A CTL clones were applied to the melanoma cells and variants resistant to 3 different CTL clones were obtained. These variants remained sensitive to other anti-A CTL clones, indicating that group A comprises at least 4 different antigens (D, E, F and A'). From a total of 76 CTL clones obtained from lymphocytes collected from the patient at various times, we found that 45 were anti-B, 17 were anti-C, 2 were anti-D, 9 were anti-E, 2 were anti-F and I was anti-A'. It is therefore likely that the 6 antigens identified by these CTL clones represent all or nearly all the transplantation antigens recognized by autologous CTL on this human melanoma.

Antigens, Neoplasm↗
PubMed1988

Definition of DRw10 specificity by restriction fragment length polymorphism.

The purpose of this study was the RFLP characterization of the DRw10 specificity. Twenty-two DRw10 cells were tested: the DNAs were digested by seven restriction enzymes and hybridized with DR beta, DQ beta and DQ alpha probes. Hybridization with DR beta revealed a pattern particular to the DRw10 specificity, with a specific TaqI 12.5Kb fragment. Hybridization with both DQ-specific probes showed that DRw10 is always associated with a special DQw1 subtype: DQw5. Furthermore, at DR and DQ levels, the 22 DRw10 cells behaved homogeneously.

Alleles↗
PubMed1988

[Increase of the frequency of HLA DR4 antigens in recurrent arterial hypertension of pregnancy].

We studied the frequency of HLA DR antigens in 96 women whose 50 with preeclampsia (PE = proteinuria greater than 0.5 g/l + HTA) and 46 with gestational HTA (GHTA = pregnancy-induced HTA without proteinuria). Sixty had later pregnancies (28 PE and 32 GHTA) and were followed for from 3 to 23 years (m = 8.5 yrs) after the first pregnancy. HLA DR antigen distribution was determined by a search on B lymphocytes for the 10 antigens of locus DR. The normal population included 38 control couples (76 mothers and fathers) with normotensive pregnancies (A) and 200 healthy controls recruited from a local blood donor population (B). The frequency of alleles was compared to that of the different group of primiparous women and whole group of women with later pregnancies. Significant variations were evaluated by the chi 2 test, using Woolf's method: the p values obtained was multiplied by the number of antigens looked for (p corrected or pc). Only the DR4 antigen, present in 19.7% of control couples (A) and 26.5% of the blood donor population (B), was increased in proportions that depended on clinical classification: 54.3% (pc less than 0.005 with A, less than 0.007 with B) in all primiparous women with GHTA, 38% (NS) in all primiparous women with PE. However significant variation was also observed when the frequency of DR4 in PE women was compared to that in only women of A (38% vs 5.2%, pc less than 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Female↗
PubMed1988

Effects of clinical combinations of antileukemic drugs on DNA ligase from human thymocytes and normal, stimulated, or leukemic lymphocytes.

Human DNA ligase was purified from different kinds of immunocompetent cells: thymocytes, normal and stimulated lymphocytes, blasts from ALL (Burkitt and non-T, non-B) and ANLL (M1, M2, and M5). Based upon the protocol for the treatment of these leukemias, the purified enzymes were assayed in the presence of routinely used combinations of antileukemic drugs. At the range of concentration tested (between 0.1 and 5 microM) some drugs taken separately were totally inactive on the enzyme from the different sources. For those being inhibitory, when used in combination their effect was always different from what was observed when the compound was tested alone. Some combinations were more effective in inhibiting the enzyme from leukemic than from normal cells (vincristine + cyclophosphamide + prednisone in ALL and rubidazone + Ara-C, Ara-C + m-AMSA, in ANLL). However, some combinations of drugs are without effect on ligase from leukemic cells at this dose range (vincristine + rubidazone + Ara-C + prednisone and adriamycin + asparaginase + Ara-C in ALL or etoposide + Ara-C, adriamycin + cyclophosphamide in ANLL). This is the first direct observation of the effect of cytostatic drugs on DNA ligase, a key enzyme of the DNA replication and repair process. The clinical consequences of these observations are discussed in an attempt to selectively inhibit replication, thereby division, of cancer cells.

Adolescent↗
PubMed1987

Porphyria cutanea tarda and HLA-linked hemochromatosis. Evidence against a systematic association.

This study was designed to test the hypothesis that a hemochromatosis allele is implicated in the expression of porphyria cutanea tarda. HLA phenotypes were determined in 69 porphyria cutanea tarda patients, 42 of which had the sporadic type (normal erythrocyte uroporphyrinogen decarboxylase activity) and 27 unrelated patients who had the familial type (diminished erythrocyte uroporphyrinogen decarboxylase activity). The incidence of HLA antigen A3, a marker of the hemochromatosis allele, was identical in the sporadic patients (23.8%), in the familial patients (22.2%), and in the controls (24.5%). Furthermore, no clinical difference could be found between A3 and non-A3 patients. These results demonstrate no systematic association between hemochromatosis and porphyria cutanea tarda in the population studied. Another HLA-linked gene, however, could be implicated in the expression of the disease as HLA antigen DR7 presented an incidence statistically different (p less than 0.05) between sporadic (16.6%) and familial patients (43%).

Adult↗
PubMed1987

Isolation of a human major histocompatibility complex class I gene encoding a nonubiquitous molecule expressed on activated lymphocytes.

The human major histocompatibility complex is a multigene family containing at least 20 class I genes. Included within this family are the loci encoding the highly polymorphic HLA-A, -B, and -C antigens present at the surface of most nucleated cells. The large number of genes detected with class I probes by Southern blot analysis and the existence of serological reagents defining nonubiquitous, non-HLA-A,B,C class I antigens suggest that products other than HLA-A,B,C antigens are encoded within the class I gene family. These products might be the human counterparts of the murine Qa and TL antigens. In order to identify non-HLA-A,B,C genes, we have developed a probe, JF11, located in noncoding regions flanking the HLA-A locus. This probe detects only a limited number of class I genes and does not detect HLA-A,B,C-associated restriction fragments on Southern blots. This probe was used to screen a human cosmid library. Some of the cosmids isolated with this probe were then transferred into mouse fibroblasts expressing human beta 2-microglobulin. One of the transfectants specifically reacts with one alloantiserum (HA2) that detects HLA class I molecules specific to HLA-A2-positive, phytohemagglutinin-activated T cells and not found on resting T or B cells. Data presented in this paper provide evidence for the isolation and expression of a class I gene encoding a nonubiquitous class I antigen that could be a human analogue of the murine Qa antigens.

Animals↗
PubMed1987

A European workshop to investigate technical problems of using HLA monoclonal antibodies in microcytotoxicity assays.

Various methods for controlling carryover from monoclonal antibodies (MCA) used in the microcytotoxicity assay to detect HLA antigens were investigated by 45 European laboratories. Carryover was demonstrated in most laboratories when using standard techniques (i.e. as for allo-antisera). Taking into consideration factors such as technical ease, time, accuracy and reagent availability, nearly half the participants selected the "no-touch" technique for adding cells and complement as being the best method for controlling carryover in their laboratory. (This method allows the needle of the Hamilton syringe to touch the oil but not the antibody in each well). Most participants (75%) thought that at least one diluent well was still necessary between each MCA well, even when using their preferred technique.

Antibodies, Monoclonal↗