Biomedical subjects

J C Bensa

Publications and source records attributed to J C Bensa.

58 records · Page 4Linked to original sources

PubMedDate not supplied

[Androgens and prolonged complete remissions in acute non lymphoblastic leukemias. Results of a systematic treatment with stanozolol associated with chemotherapy (author's transl)].

An androgen (stanozolol: 0,15 mg/kg/d) was systematically associated to the treatment of acute non lymphoblastic leukemias, since the beginning of induction therapy (vincristin, daunorubicin, prednisone) and throughout the maintenance period (6-mercaptopurine and methotrexate). Thirty-six patients less than 60 years old (median age: 44 years) presenting with acute non-lymphoblastic leukemia were entered to the study. Sixteen achieved complete remission (C.R.), i.e. 44% of the whole and 53% of treated patients. Out of 16 patients with complete remission, 4 relapsed during the observation period which lasted 4-1/2 years. The stability of the hematologic equilibrium in patients in C.R. is the main finding of the present study. The actuarial curve of the duration of the first complete remission reaches a "plateau"; after the 8th month only one relapse was observed in 9 patients. The rate of C.R. at 2 years is 76 +/- 23%. As compared to the results from other schedules of treatment, this rate appears significantly better, specially in the case of immunotherapy (p less than 0,001). A prospective randomized study is now suggested as to confirm this result; its therapeutic and theoretical basis and perspectives are discussed.

Adolescent↗

PubMedDate not supplied

[Biochemical data on C1 intrinsic activation (author's transl)].

C1 activation can be triggered by immune complexes and various effectors such as extrinsic proteases, bacterial or viral membranes, polyanions and polysaccharides. The basic mechanism of activation involves a limited proteolytic cleavage of C1r, with the generation of a proteolytic activity. Highly purified proenzymic C1r was obtained in high yield from human plasma by an indirect affinity chromatography step. Activation of isolated C1r in a fluid phase proceeded according to two distinct coexisting mechanisms: 1) an autocatalytic intradimer activation mediated by the pro-site of non-activated C1r; 2) an autocatalytic interdimer proteolysis triggered by nascent activated C1r formed in the course of the first reaction. DFP and C1-inhibitor did not have any effect on the first mechanism but were able to block the second mechanism. C1 activation is discussed in the light of recent results obtained by others from electron microscopy, and a tentative model is proposed.

Antigen-Antibody Complex↗

PubMedDate not supplied

[Erythroblastopenia in a child with immune deficiency and hyper IgM].

The authors report the case of a boy with a history of recurrent infections, who presented with erythroblastopenia at age 5 years. An immune deficiency with hyper IgM was found. Erythroblastopenia appeared to be related to a serum inhibitor of erythropoiesis. This inhibitor was present in the serum IgM fraction and acts by blocking the erythropoietic activity of a soluble substance in the serum, which is not erythropoietin but which could be a cofactor of this hormone. A series of 5 plasma exchanges, performed in 10 days, permitted to clear the inhibitor and induced remission, still persisting after a 12 month follow-up.

Child, Preschool↗

PubMedDate not supplied

[Interactions between complement system and bacterial walls].

The complement system is involved in the antibacterial defence either with a delay, following the specific antibody response, or immediately through a direct interaction between complement components and the bacterial cell wall. Several gram- bacteria initiate the classical pathway through direct interaction between C1 and the lipid A of the lipopolysaccharides; this activation depends upon the structure, the accessibility and the state of polymerization of the lipopolysaccharides. Gram+ and gram- bacteria are able to activate the alternative pathway through a covalent C3b binding. Capsules appear to prevent activation due to their high content of sialic acid, which probably accounts for the virulence. As targets, bacteria may undergo opsonization mainly by C3b, or lysis through transmembrane channels formed by terminal components from C5b to C9.

Bacteria↗