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Biomedical subjects

L Degos

Publications and source records attributed to L Degos.

At least 289 records · Page 16Linked to original sources

Further studies on a specific platelet antibody found in Bernard-Soulier syndrome and its effects on normal platelet function.

An IgG antiplatelet antibody found in a multitransfused patient with Bernard-Soulier syndrome (BSS), reacted with a normal platelet surface antigen of 150 000 daltons which was similar to the glycoprotein missing from BSS platelets. The BSS platelet antibody (BSS-Pab) aggregated all control platelets which then released ADP and 5-HT and synthesized thromboxane. When mixed with the antibody, BSS platelets did not aggregate, did not release ADP and 5-HT and failed to synthesize thromboxane. The BSS-Pab was not inactivated by incubation with BSS platelet stroma. While the antibody did not aggregate thrombasthenic platelets, its aggregating activity was lost after incubation with their stroma. The BSS-Pab did not provoke ADP or 5-HT release or thromboxane synthesis in thrombasthenic platelets or in the platelets of a patient with platelet cyclooxygenase deficiency or in normal platelets treated with indomethacin. The aggregating, release and synthetic responses of platelets after binding of BSS-Pab to its membrane antigen (probably glycoprotein I) requires the presence of glycoprotein IIb and/or IIa and the normal metabolism of arachidonic acid.

Antibodies↗

HLA in populations: an approach for genetical susceptibility to cancer.

The geographical correlations between the incidence of various cancers and the HLA and ABO antigen frequencies are studied. There is, for example, a positive correlation between breast and colorectal carcinoma and AI, B8 and B12 antigens, and a negative one between prostate carcinoma and B12. The role of the HLA system itself or other genes involved in these associations is discussed. This study gives some evidence of a possible genetic background of susceptibility or resistance to cancer.

ABO Blood-Group System↗

[Genetic markers and disease susceptibility (author's transl)].

The HLA system includes several genes and each of them is polymorphic. Several associations between some HLA alleles and the susceptibility to various diseases are already described. Three kinds of associations are reported: [1] a constant association between an HLA allele and a disease whatever the tested population, [2] an association between the HLA allele and a disease varying according to the tested populations, [3] an association probably due to a mutation of metabolic gene closely linked to HLA. These three kinds of associations probably correspond to three different mechanisms.

Alleles↗

Clinical activity of detorubicin: a new anthracycline derivative.

The anthracycline derivatives are intercalating drugs which are of major importance in the treatment of leukemias and in the management of solid tumors. Structural analogs have been prepared by semisynthetic modifications in an attempt to extend the spectrum of antitumor activity and to reduce toxicity (acute myelosuppression and cardiotoxicity). This report concerns our preliminary clinical experience in 111 patients who received detorubicin. Two dose schedules were used in acute leukemia patients. Sequential doses were active in acute leukemia relapses but the mucous membrane toxicity was excessive; more recently, intermittent doses proved active in acute leukemia relapses (one 6-mg/kg dose) and in a patient with resistant Burkitt's lymphoma. In non-Hodgkin's lymphomas, a complete response rate of 71% was achieved with an intermittent schedule (3 mg/kg/day X 3 weeks). A remarkable shrinkage of skin involvement was also observed. Detorubicin showed a high activity in mycosis fungoides (five regressions among six patients) and some activity in soft tissue sarcomas, osteosarcomas, and various solid tumors.

Acute Disease↗

Principal clinical features and prognosis in chronic lymphocytic leukemia.

A prospective study of 102 patients with chronic lymphocytic leukaemia (CLL) on 30 parameters subdivided into 77 variables was analyzed by correspondence analysis, a variant of principal component analysis, which allows simultaneous graphical representation of patients and variables. This statistical method clearly defined three principal clinical features recognized at the time of diagnosis: lymph node proliferation, lymphoid infiltration and cytopenia. Cytopenia was clearly subdivided into peripheral and central types. Each of these clinical features were derived from clinical and laboratory observations which agreed with each other. Simple examination permitted an evaluation of these three syndromes. They seemed to be independent of each other except for a relationship between central cytopenia and lymphoid infiltration. Thus clinical staging at the moment of diagnosis must record three scales of severity corresponding to the three independant clinical features. Prognosis was essentially related to cytopenia, whatever the mechanism. In a further analysis of the subsequent progress of the disease, a "common path" for patients was found terminating in a region of the graph where marked splenomegaly and cytopenia were plotted. We conclude that it is necessary to consider the three clinical features independently in a clinical staging. This study emphasizes the poor prognosis of cytopenia and splenomegaly and indicates that follow up and treatment should take this feature into account.

Anemia↗

Some chronic lymphocytic leukemia cells bearing surface immunoglobulins share determinants with T cells.

One set of antigens is common to some chronic lymphocytic leukemia (CLL) cells bearing surface immunoglobulins (Ig) and normal T cells. Proliferating cells from thirty-eight patients were studied with four antisera recognizing normal human T but not B cells. These antisera were raised in rabbits against (a) Sezary cells, (b) blood lymphocytes from a patient with sex-linked agammaglobulinemia, (c) T lymphoblasts and (d) thymus cells. In four CLL cases, the cells expressed the receptor for sheep erythrocytes and lacked surface Ig. Cells from thirty-four CLL cases bore monoclonal surface Ig and did not bind sheep erythrocytes. Twelve out of these thirty-four cases of CLL had cells which were lysed by one or, more frequently, by the four anti-human T cell xenoantisera. By absorption experiments, one set of at least three antigens common to the cells of some of these CLL and T cells was defined. Depending on the patient, the cells can either carry one, some or all of the antigens of this set. However, it was also demonstrated by absorption that these cells lacked antigens particular to the T cell lineage, while the cells from T CLL cases carried both sets of antigens.

Animals↗

Prognosis and treatment of acute lymphoblastic leukemia. Study of 650 patients.

The complete hematological remission (CHR) rate, duration of remission and survival were studied in relation to age, peripheral blast cell (PBC) count, presence or absence of tumor masses, cytological type, and treatment in 650 patients with acute lymphoblastic leukemia. Prognostic factors were considered separately and divided into prognostic classes. Age and PCB count correlated with both the rate and the duration of CHR. This correlation was still observed for more recent treatment schedules though it appears to be becoming progressively less significant. Meningeal relapses were more common in patients less than 1 year old and in those with a high PCB count. It is suggested that stratification of patients according to such factors as age, PCB count, presence or absence of tumor, and cytological type might be necessary for the design of new treatment protocols and for the evaluation of their results.

Adolescent↗

HL-A markers in the Vietnamese population.

A total of 126 normal, unrelated individuals from northern central and southern Vietnam have been typed for 32 alleles of the A and B loci, including B HS. The gene, haplotype frequencies and delta values obtained are compared with those of four other Mongoloid populations. The gene frequencies were similar to those found in a Chinese (Cantonese) population.

Asian People↗

Histocompatibility antigens in two American Indian tribes of French Guiana.

Two South American Indian populations were typed for HLA antigens. In each, the individuals typed were related and their genealogies were known. Determination of their genotypes was done; there seemed to be neither excess nor deficiency in homozygotes. The antigens observed, A2, A9, Aw19.2 (Aw30-Aw31), A28 for the first locus and B5, Bw15, Bw35, Bw40 for the second locus are in accordance with those previously described for other South American Indians. The two populations belong to the same primary linguistic family Tupi-Guarani and they live in the same geographic area, but there was no intertribal marriage until recently. Genetic drift can explain the differences observed.

French Guiana↗

A haplotype study of HLA complex with special reference to the HLA-DR series and to Bf. C2 and glyoxalase I polymorphisms.

Fifty-three French families were typed for alleles at seven loci of the HLA complex (HLA-A, -B, -C, -DR, -Bf, -C2 and -GLO) and 212 haplotypes were demonstrated. Eleven recombinations were observed (two A/B, two A/C, two B/Bf, one Bf/D and four D/GLO). The linkage disequilibrium was calculated not only between two alleles (delta) but between three, four...seven alleles (D). In order to compare the intensity of D values in the various haplotypes, the influence of the differences in gene frequencies was eliminated by the introduction of the standardized Ds (Ds = D/D max). The number of haplotypes in disequilibrium is relatively limited since most of the significant Ds involved about 17 haplotypes. For some haplotypes, the disequilibrium covered the whole distance from A to GLO but the stronger disequilibrium concerns the C to Bf or C to DR segment. Three hypotheses (isolation, admixture of population and selection) concerning the formation and maintenance of the disequilibria are discussed.

Epitopes↗

Acquired IgG antibody occurring in a thrombasthenic patient: its effect on human platelet function.

In subagglutinating amounts, an IgG antibody isolated from the plasma of a polytransfused thrombasthenic patient (L) inhibited ADP-, epinephrine-, collagen-, and thrombin-induced aggregation of normal human platelets. The inhibition of ADP-induced aggregation was strongly diminished following the prior incubation of the antibody with control human platelet stroma but not with the stroma prepared from the platelets of two different thrombasthenic patients. The IgG(L) did not affect the binding of 14C-ADP to control human platelet membranes and did not inhibit the ADP-induced shape change. Bovine factor VIIIVWF-induced agglutination and ristocetin-induced aggregation of control human platelets were not inhibited in the presence of the antibody. The IgG(L) strongly inhibited ADP-induced retraction of reptilase clot and thrombin-induced clot retraction. This antibody therefore induced a thrombasthenialike state in normal human platelets, suggesting that the antigenic site recognized by the antibody plays a central role in the later stages of the mechanism of platelet aggregation induced by physiologic aggregation-inducing agents.

Adenosine Diphosphate↗

[Familial leukemia (author's transl)].

Among 2966 acute leukemia, 26 familial cases were reported. Leukemia occured mainly in the first relative individuals and particularly in the sibship. The relative risk for a sib of leukemic patient is four time more than for random people. Leukemia was often similar among patients of the same family and the onsets of the disease occured approximatly at the same age whatever the time between the dates of diagnosis. Twins with leukemia were often monozygotous. Relative risk of leukemia among twins, decreases according to the age: the probability of leukemia for a twin is: (a) 100 p. cent if the other twin is leukemic before 1 year old; (b) 15 p. cent between 1 to 4 years old and (c) similar to other sib after 4 years old. Among chronic leukemias, only chronic lymphocytic leukemia seems to have a genetic background for susceptibility. Some familial diseases (congenital aplastic anemia, Bloom's disease, Ataxia telangiectasia) or congenital diseases (Down's syndrome) increase the risk of leukemia.

Age Factors↗