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Biomedical subjects

J Bernard

Publications and source records attributed to J Bernard.

At least 163 records · Page 9Linked to original sources
PubMed1989

Epidemiology of leukaemia.

The history of the epidemiology of leukaemia provides us with models which are very useful even today and their implications for the future are still more important. Thus, in the present study, we shall review the history and present state of the epidemiology of leukaemia, as well as its future prospects. In the fifth century B.C. Hippocrates already advocated studying the climatic, geographical and physical environment as well as the behaviour of individuals and of their eating and drinking habits in order to understand the origin of a disease. At present, the epidemiology of leukaemia is still based on these ancient precepts.

History, 20th Century↗
PubMed1989

Use of Old World monkeys for acquired immunodeficiency syndrome research.

Mangabeys, macaques, and baboons persistently infected with human immunodeficiency virus (HIV)-2 NIH-DZ demonstrated no signs of immunodeficiency disease after 6-11 months following seroconversion. Thus Old World monkeys provide an animal model to investigate the effects of passive immunization (anti-HIV-2 antibodies) on HIV infection in primates.

Acquired Immunodeficiency Syndrome↗
PubMed1988

A group specific anamnestic immune reaction against HIV-1 induced by a candidate vaccine against AIDS.

The first experimental immunization of humans against the AIDS retrovirus, HIV-1, was started in a series of HIV seronegative, healthy volunteers in November 1986. For the primary vaccination recombinant vaccinia virus (V25) expressing the complete gp160 env protein of the HTLV-IIIB strain of HIV-1 was introduced by scarification. This elicited a weak primary response which we subsequently attempted to enhance by additional immunizations (boosting), using four different immunization protocols. We report here that intravenous injection of paraformaldehyde-fixed autologous cells infected in vitro with V25 (individual D.Z.) gave the best results. This individual received second and third boosts of intramuscular gp160 derived from an HTLV-IIIB clone using the hybrid vaccinia virus/bacteriophage T7 expression system. An anamnestic humoral and cellular immune reaction was achieved for over one year after the original vaccination, with high levels of antibodies to the viral envelope, and neutralizing antibodies against divergent HIV-1 strains such as HTLV-IIIB and HTLV-IIIRF (also called HTLV-III HAT) after the first boost. In addition, group-specific cell-mediated immunity and cell-mediated cytotoxicity against infected T4 cells were obtained after the primary vaccine and enhanced by the boosts. Finally, skin tests showed both immediate and delayed hypersensitivity to gp160 in vivo. Although this protocol is not practical for a large scale vaccine trial, our results show for the first time that an immune state against HIV can be obtained in man.

Acquired Immunodeficiency Syndrome↗
PubMed1988

Phenotypic instability of tumor cell clones: clonal expression of Fc receptors in the human leukemic K562 cell line and its relationship with hemoglobin expression.

Membrane expression of Fc receptors (FcR) was studied in clones of human K562 cells during short- and long-term culture. Using a manual cloning method, well-defined clones were generated either from FcR-positive or FcR-negative cells. The fourth day after cloning, the majority of cloned cells manifested shifts in FcR expression without evidence of an orderly pattern. After long-term culture (about 34 passages), most clones expressed FcR values close to those found in the cell line. In addition, the selection of six clones expressing a stable FcR phenotype suggested that the presence of FcR is correlated to a low hemoglobinization of the multipotential K562 cells.

Cell Differentiation↗
PubMed1988

Distribution of glutamate decarboxylase-like immunoreactivity in the sixth abdominal ganglion of the cockroach Periplaneta americana.

An antiserum against glutamate decarboxylase (GAD) of the rat brain was used to locate GAD activity in sections of the nervous system of the cockroach, Periplaneta americana. The sixth abdominal ganglion was chosen because electrophysiological evidence suggests the presence of GABAergic inhibitory synapses in the cercal-giant interneuron system. Groups of somata and numerous fibres and tracts were positively labelled by the GAD antiserum. A posterior group of labelled somata could be identified close to the entry of the cercal nerves. A line of somata clusters lay along a ventro-lateral furrow. Another discrete row of GAD-like cells was located dorso-laterally. Some small cells among the dorsal unpaired neurons were labelled. A small central group appeared under these cells. An abundance of GAD-like processes and transversal tracts were found within the neuropile. The different systems of GABAergic inhibitors in the ganglion are discussed; in particular we show that the fibres of cercal nerve X are not labelled. This demonstrates that the latter act on the giant fibres via interneurons. We suggest that the group that sends axons into the overlapping region between the cercal nerve and the giant fibre could be the inhibitory interneurons involved in this system.

Abdomen↗
PubMed1988

Cytopathic effect of human immunodeficiency virus in T4 cells is linked to the last stage of virus infection.

A principal feature of acquired immunodeficiency syndrome is depletion of T4 lymphocytes, which is partly due to a direct cytopathic effect of the virus. Both syncytial formation (viral-induced cell fusion) and premature cell death have been cited as the major cause for this phenomenon. By kinetic analysis of cell proliferation and cell lysis we show that the cytopathic effect correlates chiefly with virus production from infected cells, including giant syncytial cells. Most T4 cells were, at least transiently, infected by human immunodeficiency virus (human T-lymphotropic virus type IIIB strain); however, after phytohemagglutinin activation, only 10-30% of infected cells express virus (and die) at any one time, indicating that virus production, followed by cell killing, is linked to immune activation and cell differentiation. We also show that an interval exists before viral release, in which expression of viral antigens occurs on the cell surface, suggesting that infected cells are immunogenic before viral production. If so, they may induce a cell-mediated immune response that could minimize dissemination of human immunodeficiency virus, a possibility that has influenced our approaches to the development of a vaccine for prevention of acquired immunodeficiency syndrome.

Cell Line↗
PubMed1987

Double phenotyping of immunoregulatory T cell subsets in patients with allergic asthma.

In order to determine whether the dissection of helper/inducer (CD4+) and suppressor/cytotoxic (CD8+) lymphocyte subsets with Leu 8 reagent would reveal any differences between allergic asthma patients and non-atopic controls, we compared in both groups the 'true helper' T cell subset (Leu 8- CD4+), responsible for the major helper effect, and one of the suppressor T cell subpopulations (Leu 8- CD8+). Peripheral blood mononuclear cells from sixty-nine individuals, including nineteen extrinsic asthmatics, fifteen intrinsic asthmatics, seventeen patients with chronic obstructive lung disease and eighteen healthy controls, were comparatively analysed. Although total CD4+ cells and total CD8+ cells were similar for all groups, we found in the extrinsic asthma patients group a significant increase in the number of 'true helper' T cell sublineage (Leu 8- CD4+) and of suppressor cells expressing Leu 8- CD8+ phenotype. Such imbalances may be implicated in the pathogenesis of atopic asthma.

Adult↗