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Biomedical subjects

J Bernier

Publications and source records attributed to J Bernier.

154 records · Page 9Linked to original sources
PubMedDate not supplied

Phenotyping of beluga whale blood lymphocytes using monoclonal antibodies.

Widespread efforts are currently made to classify morphologically indistinguishable lymphocyte subpopulations in several species. In order to increase the knowledge in cetacean immunology, cross-reactivity of antibodies against bovine, human, ovine and mouse cell surface proteins was tested on beluga whale (Delphinapterus leucas) peripheral blood lymphocytes using flow cytometry. Anti-MHC class I and II as well as anti-CD2 reacted with virtually all peripheral blood lymphocytes. Anti-TCR gamma delta and anti-CD4 reacted with respectively 31% and 30% of peripheral blood lymphocytes. B lymphocytes were identified by an anti-surface IgM which was present on 6% of blood lymphocytes. Specificity of these antibodies was demonstrated by immunoprecipitation of beluga proteins with similar molecular weight to that of other species. These results could be useful for further immunotoxicological evaluation of highly versus mildly contaminated populations of belugas.

Animals↗
PubMedDate not supplied

Purification of functional T lymphocytes from splenocytes of the beluga whales (Delphinapterus leucas).

In an effort to gain knowledge on immune functions in beluga whales, Delphinapterus leucas, we have used two physical methods for the purification of T lymphocytes of spleen cells. Isolation by sheep red blood cells (SRBC) rosetting and by adherence on nylon wool columns were tested. SRBC-rosetting gave unreliable results in obtaining purified T cells. Therefore, the purification of T cells was done using nylon wool columns. Less than 3% of the IgM(+) B cells remained in effluent populations. In the later population, 45% gave positive staining with mouse anti-human CD4 allowing us to verify functionality of the cells. The study of calcium mobilization and tyrosine kinase activation, mediated by CD4 cross-linking permitted verification of the functionality of cells. We also showed that upon activation with mitogens, beluga T cells upregulate the density of MHC class II molecules on their surfaces. CD4 cross-linking with a specific antibody inhibited the proliferation response. Overall, the activation of beluga whales lymphocytes did not differ markedly from what is known in other species. This study can help in the groundwork for functional investigation of the beluga whale's immune system.

Animals↗
PubMedDate not supplied

Radio-immunological study of the regulation of interleukin-2 production in peripheral blood mononuclear cell cultures from normal subjects and rheumatoid arthritis patients.

A radio-immunoassay for human T cell growth factor, also called Interleukin-2 (IL-2), has been carried out using a recombinant IL-2 preparation as tracer and a polyclonal rabbit antiserum. The assay is highly specific for IL-2: there is no cross-reaction with either type I and II interferons, epidermal growth factor or tumor necrosis factor alpha. Using the sequential saturation procedure the limit of sensitivity was 0.5 U/ml. Intra- and between-assay coefficients of variation were 8 and 11%, respectively. With this assay, IL-2 recovery in serum and peripheral blood mononuclear cell culture (P.B.M.C.) medium was 79 and 95%, respectively. In serum of 109 normal subjects and 102 rheumatoid arthritis patients mean IL-2 concentrations (+/- SD) were 1.5 +/- 0.5 U/ml and 1.4 +/- 0.4 U/ml respectively. The IL-2 production by P.B.M.C. in vitro was also studied. In unstimulated cultures, IL-2 release remained undetectable, i.e. below 0.5 U/ml. After stimulation of mononuclear cells from 36 normal subjects with increasing amounts of phytohemagglutinin (PHA), the 3H-thymidine incorporation followed a bell-shaped curve, the maximum response being observed at a 2.5 micrograms/ml PHA concentration. After a 72-hr mononuclear cell stimulation, IL-2 release increases with PHA concentrations ranging from 0 to 10 micrograms/ml. In patients with rheumatoid arthritis (R.A.), P.B.M.C. incorporated 3H-thymidine as in normal subjects. In contrast, mean +/- SEM IL-2 production by P.B.M.C. from patients with inactive RA (5 +/- 0.9) and active disease (1 +/- 0.5) was significantly lower than that from normal subjects (12 +/- 0.7 ng/ml).(ABSTRACT TRUNCATED AT 250 WORDS)

Arthritis, Rheumatoid↗
PubMedDate not supplied

[Selective intra-arterial perfusion of the cancerous breast: quantitative study].

Mammary tissue diffusion of a radioactive marker (Pertechnetate-Tc99m), intravenously or selectively and intraarterially injected, has been studied in 15 breast cancers; a considerable increase of that diffusion with co-injected degradable starch microspheres has been demonstrated. A clinical application of these techniques should be soon considered.

Breast Neoplasms↗
PubMedDate not supplied

Production of interferon gamma by peripheral blood mononuclear cells from normal subjects and from patients with rheumatoid arthritis.

A radioimmunoassay for human interferon gamma (IFN-gamma) has been carried out using a recombinant glycosylated interferon (Hu IFN-gamma) as tracer, the N.I.H. reference preparation (Gg 23-901-530) and a polyclonal rabbit antiserum. The assay is highly specific for IFN-gamma: there is no cross-reaction either with interferons alpha and beta, Interleukins 1 and 2, tumor necrosis factor alpha and beta or with various brain peptides. The sequential saturation procedure allowed a sensitivity of 0.4 U/ml with intra and between assay coefficients of variation less than 8 and 12%, respectively. The in-vitro production of IFN-gamma by peripheral blood mononuclear cells (P.B.M.C.) was also measured. In unstimulated cultures, IFN-gamma production remained undetectable, i.e. below the 0.4 U/ml sensitivity level. After stimulation of P.B.M.C. from normal subjects with increasing amounts of PHA, both the 3H-thymidine incorporation and IFN-gamma release followed bell-shaped curves. There was no significant difference of 3H-thymidine incorporation between PHA stimulated cultures (0.2 and 2.5 ug/ml) from normal subjects (36 cases) and those with active (16 cases) or non-active (14 cases) rheumatoid arthritis. At two PHA concentrations of 0.2 and 2.5 ug/ml, mononuclear cells from patients with active disease produced significantly less IFN-gamma than those from either controls or cases with non-active disease.

Adult↗
PubMedDate not supplied

[Arteriovenous fistulas complicating in situ venous femoropopliteal bypass. A sample case].

Arteriovenous communications are a rare but specific complication of in situ saphenous vein arterial bypass. In this bypass procedure, some collaterals of the saphenous vein may remain patent. In this report, a characteristic example illustrates this complication. Local and general manifestations secondary to the development of these fistulas must be prevented by complementary surgical or radiological obliteration.

Arteriovenous Fistula↗
PubMedDate not supplied

[On preclotting of woven Dacron vascular prostheses (author's transl)].

The role and the clinical value of common protocols of preclotting for a woven Dacron vascular prosthesis have been investigated. A comparative study of blood loss was carried out for Standard Woven De Bakey protheses inserted in a specially constructed extracorporeal blood circuit with canine models. The system detected transport of blood across the wall of the prostheses. These measurements were supplemented by gravimetric assessment of blood clot density and scanning electronmicroscopy examination of the internal surfaces of the prostheses. The pre-operative protocols investigated included : absence of pre-treatment, precoagulation with anticoagulant-free blood and various techniques using heparinized blood subsequent to an initial blood contact (modified method of Sauvage). The effect of using heparinized animals was also investigated. Leakages in unclotted prostheses could be reduced almost five fold by any precoagulation technique. Heparinization did not cause a significant increase in leakage and considerably improved the quality of the newly deposited blood product lining on the prostheses which consisted almost entirely of fibrin and eliminated any embolization.

Animals↗