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Biomedical subjects

M Billard

Publications and source records attributed to M Billard.

32 records · Page 2Linked to original sources
PubMed1989

Hospital dispersion of Staphylococcus epidermidis isolates resistant to a fluoroquinolone, pefloxacin.

Since 1985, nosocomial infections have been frequently treated with a new fluoroquinolone, pefloxacin, at the Cardiological and Neurological Hospital in Lyon. From 1986 to 1988, the incidence of resistance of clinical Staphylococcus epidermidis strains to pefloxacin increased from 31 to 57%. Dispersion of these resistant strains in the hospital environment was recognized when they were detected on 22% of staff members' fingers (139 samples were investigated) and in 28% of the environmental samples (180 were investigated). There was an association between carriage rate and work place. Most of the pefloxacin-resistant S. epidermidis were resistant to oxacillin, gentamicin, erythromycin, cotrimoxazole and fosfomycin. Intensive use of pefloxacin selected multiresistant S. epidermidis which became ubiquitous in the hospital environment.

Carrier State↗
PubMed1988

High frequency of plasminogen activator secretion by malignant human lymphoid cell lines of T-cell type origin.

Diffuse defibrination is rarely observed in acute lymphoblastic leukemia (ALL). Clinical and immunologic data suggest that it is more likely to occur in T cell derived ALL. The current investigation involved the secretion of plasminogen activators (PA) of tissue type (t-PA) or urokinase type (U-PA) by testing supernatants of 21 permanent human leukemic cell lines originating from various hematopoietic lineages and one induced lymphoblastoid cell line. (LCL) The amount of PA in each supernatant was determined by biologic and immunoenzymologic assays. The correspondence with the expected molecular weight (MW) according to the PA type was checked by zymography. PA secretion of U-PA type was observed in the three myeloid cell lines. Except for the normal LCL, no B-lymphoid lineage related cell lines of various levels of differentiation displayed PA secretion, whereas PA activity was observed in the supernatant of six of nine malignant T-cell lines. The T-leukemic cell lines CCRF CEM, KE 37, HUT 78, and HUT 102 released U-PA-like activity. Peer released t-PA-like activity and CCRF-HSB2 supernatant showed both types of PA activity. These findings are discussed in view of the natural history of these diseases and the stage of differentiation of the cell lines.

Humans↗
PubMed1986

Screening monoclonal antibodies against cell-surface antigens. High frequency of natural antibodies.

Two commonly used methods for screening hybridoma supernatants against cell-surface antigens were performed simultaneously on the supernatant culture fluids of different hybridizations, and compared with the detection of Ig secretion. Supernatants reacting with glutaraldehyde-fixed cells (ELISA (Enzyme-linked immunosorbent assay) on fixed cells) are mostly non-specific for the immunogen; in addition, with this method, only half of the antibodies detected by immunofluorescence are identified. These results can be explained by the frequent occurrence of hybridomas secreting antibodies displaying 'natural antibody' properties, which are strongly reactive with intracellular antigens, and apparently made accessible by the fixation procedure. Since artefacts impair the interpretation of results with ELISA on fixed cells, and complement-mediated cytotoxicity usually as a low yield, membrane immunofluorescence remains the best method for screening hybridoma antibodies.

Animals↗
PubMed1985

A new set of monoclonal antibodies against acute lymphoblastic leukemia.

Six monoclonal antibodies produced by immunization of Balb/c mice with common acute lymphoblastic leukemia (cALL) cells were tested against various types of normal and malignant tissues. ALB1 and ALB2 are directed to the cALL antigen (CALLA gp100); ALB6 recognizes a determinant of p24; ALB7, ALB8 and ALB9 have a pattern of reactivity similar to Ba1. None of these antibodies specifically identify cALL but they should be useful tools for diagnosis or depletion of bone marrow in autologous therapy in transplantation. In addition, the example of ALB6 which acts as a platelet aggregating agent, suggests that the study of other cell systems expressing the antigens associated with cALL may shed light on the function of these antigens and subsequently on the physiopathology of the leukemic cells.

Animals↗
PubMed1985

In vitro study of the comparative behaviour of a human acute lymphoblastic leukemia cell line and a reference normal cell line towards the effects of a mitogenic lectin.

An in vitro study of the behaviour of a human acute lymphoblastoid leukemia cell line (REH) towards the action of a mitogenic lectin of Robinia pseudoacacia was carried out. The results were compared with those a reference cell line (LHN13) established from normal human lymphocytes. In both cell lines, the lectin induces agglutination (measured by counting the number of aggregates as well as the number of cells in each aggregate) and decrease of growth (measured by counting the number of cells and the incorporation of tritiated thymidine into TCA-precipitable material per 10(6) cells). The agglutination and the decrease of growth are produced at the doses of 0.5 and 1 microgram/ml of culture medium and after 4 h of exposure of cells to the lectin, respectively. These effects increase progressively with higher doses of lectin and continues throughout the culture. However, the REH line is less sensitive than the LHN13 line to the effects of lectin. Both agglutination and growth decrease of REH as well as LHN13 cell lines by the lectin are reversible; this is confirmed by the fact that the monospecific anti-Robinia lectin serum suppresses these effects.

Agglutination↗
PubMed1983

Effects of differentiation inducers on diphenylhexatriene fluorescence polarization in intracytoplasmic and plasma membranes from Friend erythroleukemia cells.

Treatment of Friend leukemia cells with dimethylsulfoxide or hexamethylenbisacetamide, which induced erythroid differentiation, resulted in enhancement of fluorescence polarization of diphenylhexatriene in not only plasma membranes, but also in intracellular membranes. In a cell variant resistant to induction, the polarization values of intracellular membranes were not affected by the inducing agents, whereas plasma membranes had the same enhancement of polarization values as in sensitive cells. Therefore, Friend cell differentiation can be associated with the effect of the inducers on intracellular membranes, but not with the effect on plasma membranes.

Acetamides↗
PubMed1983

Characteristics of platelet aggregation induced by the monoclonal antibody ALB6 (acute lymphoblastic leukemia antigen p 24). Inhibition of aggregation by ALB6Fab.

The leukemia-associated cell surface antigen p 24 is found on normal platelets as well as on Bernard Soulier syndrome and thrombasthenia type I platelets. ALB6 IgG (a monoclonal antibody against p 24) induces the aggregation of platelets from normal donors but not from thrombasthenia. In contrast, ALB6 Fab inhibits platelet aggregation induced by collagen, ADP, thrombin, ionophore A 23187 and ALB6 IgG. The results suggest that ALB6 interferes with a mechanism common to all aggregation pathways; the possible mechanisms are discussed.

Antibodies, Monoclonal↗
PubMed1978

Effects of low dose rate irradiation on the division potential of cells in vitro. IV. Embryonic and adult human lung fibroblast-like cells.

Early and late passage human embryonic lung fibroblasts were compared with early passage adult lung fibroblasts with regards to their survival (number of population doublings), after low dose rate ionizing radiation. It was found that early passage embryonic cells are quite resistant to this type of radiation. Late passage embryonic and early passage adult fibroblasts are more sensitive to ionizing radiations. The results suggest that cell aging is accompanied by an increased sensitivity to low dose rate ionizing radiation and favor the idea that aging in vitro, expressed as a function of the fibroblast division potential, is correlated with aging in vivo.

Cell Division↗
PubMed1977

[Macroscopic anatomy of the human fetal thymus in the 2d half of uterine life].

The dissection under an operative microscope of 46 foetuses from a homogeneous series measuring 80 to 390 mm C-R (crown-rump) is the subject of a gross anatomic study of the thymus. The authors point out the size, the lobulation and connections with the vascular pedicles of the neck: the thyropericardeal sheet.

Female↗
PubMedDate not supplied

[Risk factors in aorto-iliac surgery (author's transl)].

The authors report a statistical analysis of 163 operations of aorto-iliac vascular surgery. A detailed study of their 14 deaths showed the various causes of mortality (immediate post-operative thrombosis, acute renal failure, digestive complications, septic cardiac, pulmonary, hemorrhagic and cerebro-vascular accidents). This analysis, compared with the findings in all the operated patients showed the main factors of risk in this type of surgery (age over 70 years immediate and late reoperations, heart lesions, renal, pulmonary and late lesions, the risk of sepsis). The indicate the means of prevention of such accidents and the therapeutic attitude when they occur. They conclude that the contra-indications are relative, but should be observed in order to lower the risk of this surgery below 5 p. cent mortality rate.

Age Factors↗