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Biomedical subjects

J Bernard

Publications and source records attributed to J Bernard.

At least 145 records · Page 8Linked to original sources
PubMed1991

The erythroblastic island: past and future.

The erythroblastic island consists of a macrophage surrounded by erythroblasts of different maturation stages. The cohesion of cells is lost during spreading, so that the islands can no longer be seen in smears. However, in undisturbed preparations, either living or fixed, the islands can be visualized, isolated, cultured, and their function studied. Many questions remain, such as the production of growth factors by the macrophage, the causation of the adhesion of cells forming the islands, the role of calcium in the adhesion, and others. New technical advances, including flow cytometry, immunolabeling, and in situ hybridization will assist in answering these questions.

Animals↗
PubMed1990

Toluene diisocyanate-induced conformational changes of serum albumin: a study on repeated inhalations in guinea-pigs.

High responder lines of Hartley guinea-pigs were sensitized by repeated inhalations of toluene diisocyanate (TDI). After 3 weeks, we demonstrated a degree of TDI substitution of the serum-albumin-enriched fraction (AEF) and we ascertained the sensitization of the most exposed animals using PCA methodology. Fourier transform infrared spectroscopy (FT-IR), used to investigate conformational changes in AEF, highlighted the structural modifications of the native protein conformation. Such crucial changes may support, at least in part, the relationship between TDI exposure and triggering of hypersensitivity reactions.

Administration, Inhalation↗
PubMed1990

Discriminating between protective and enhancing HIV antibodies.

Most attempts to produce a vaccine against HIV-1 infection are utilizing envelope protein components. Hypothetically such vaccine candidates could stimulate production of antibodies that enhance HIV-1 infection via the macrophage route of entry and, consequently, cannot be detected in the conventional neutralization assay. To study this hypothesis we report an assay designed to evaluate the protective/enhancing activity of serum from seropositive immunized or infected individuals. Highly purified activated FcR-bearing monocytes-macrophages were infected with HIV-1 in the presence of the sera, then washed and cocultured with activated peripheral blood mononuclear cells (PBMC) from a normal donor. Productive viral infection, as evaluated by p24 antigen semiquantitative assay in the culture supernatants, allow evaluation of protective/enhancing activity of the sera. The data clearly show that protective rather than enhancing activity is present in the serum of env protein-immunized individuals.

Acquired Immunodeficiency Syndrome↗
PubMed1990

Cloning and sequencing the messenger RNA of the N gene of viral haemorrhagic septicaemia virus.

The mRNA transcribed from the N gene of viral haemorrhagic septicaemia virus (VHSV) of salmonids has been cloned in Escherichia coli and expressed. Fusion proteins were recognized by monoclonal antibody directed against the N protein from the viral particle. A 1212 bp long open reading frame (ORF) coding for 404 amino acids with a calculated Mr of 44590 was deduced from the nucleotide sequence. The ORF was preceded by a 93 bp segment including in position 42 the AACAC pentanucleotide which is presumed to be the start signal for transcription by analogy with other rhabdoviral mRNAs. The upstream 41 bp region could correspond to the covalently linked positive polarity leader RNA as also found on the N mRNA from infectious haematopoietic necrosis virus (IHNV). This may be a characteristic of fish lyssaviruses. The AAACC sequence, which is part of the leader, was not found. Amino acids 44 to 359 from IHNV and 45 to 360 from VHSV are 45.3% homologous. A strong homology which could reflect functional importance was also found for potential phosphorylation sites and hydrophobic peaks despite the fact that the two viruses evolved on different continents.

Amino Acid Sequence↗
PubMed1990

[The treatment of imported Plasmodium falciparum malaria with halofantrine. Apropos of 59 case reports (corrected and republished article orginally printed in Med Trop (Mars) 1990 Jan-Mar;50(1):113-7)].

59 cases of Plasmodium falciparum malaria fever occurring in non-immune Caucasian subjects having got a correct chemoprophylaxis by chloroquine were treated by halofantrine (HALFAN). They were given 1500 mg divided in 3 doses of 500 mg every 6 hours from D1 to D8. All them were back from a malarial highly endemic zone with chloroquine resistance. Analysis of the main biological and clinical efficiency parameters displayed very satisfactory results: disappearances of fever (mean 22 H) and parasitemia (mean 36 H) are short. After two months of monitoring, no malaria recrudescence was noted. With an efficacy of 10 p.c. associated to a noticeable clinical and biological tolerance Halofantrine is a first-class treatment of chloroquine resistant malaria fever.

Adolescent↗
PubMed1990

Bioethics and knowledge.

The acquisition of knowledge must be regarded as the first duty, as affirmed by Claude Bernard and Jacques Monod. It occupies a place in the forefront of other duties--respect for the individual and his liberty and dignity--to which the duty of knowledge must be subordinated. An attempt must be made to reconcile these diverse obligations. These three situations are described by stressing the importance of the principles that govern these studies: respect for the individual; respect for science; restriction of human experiments to what is strictly necessary; scrupulous assessment of the balance of risks and advantages; the human body is not an object of commerce; free and informed consent; solidarity between men.

Attitude↗
PubMed1989

Femoral bone density in young male adults with stress fractures.

Femoral bone mineral density (BMD) was measured by dualphoton absorptiometry in 41 young military recruits who had one or several stress fractures, during their physical training program. These fractures involved the following locations: Femur (neck: n = 10, diaphysis: n = 2), calcaneus (n = 10), tibia (n = 8), fibula (n = 3), metatarsus (n = 8). The stress fracture group generally had a lower bone density than that of a control group, consisting of 48 young military recruits matched for age, height and weight. However, the BMD was significantly lower (-10%) in patients with femoral and calcaneal locations, but it did not differ for other locations. To determine the possible effect of this intense physical activity on bone mineral mass, bone mass was measured again in 35 subjects from the control group at the end of their training. The BMD remained stable or increased in 28 subjects, but decreased significantly (greater than 2%) in 7 subjects, demonstrating the individual variability in the adaptation of bone to this stress. Our results suggest that lowered bone mass could be a factor that encourages the development of stress fractures (femoral and calcaneal) in young subjects submitted to intense physical activity to which they are not accustomed.

Adolescent↗
PubMed1989

Persistent HIV-2 infection of rhesus macaque, baboon, and mangabeys.

Six monkeys of three different species (mangabey, macaque and baboon) were infected with human immunodeficiency type 2 (HIV-2) NIH-DZ using intraperitoneal or intravenous injections of cell-free HIV-2 or autologous HIV-2-infected cells with no prior immunostimulation. Viral expression was demonstrated by reverse transcriptase activity in cells after coculture with human peripheral blood lymphocytes or by electron microscopy. Serum was analyzed by western blot, enzyme-linked immunosorbent assay (detection of antigen and antibody), and neutralization assay carried out using immunofluorescence techniques. The 6 inoculated animals seroconverted during the 1st month after inoculation and remained persistently infected after 6-11 months. We also observed proviral DNA by genomic analysis in the six tested samples. No sign of immunodeficiency disease has been observed so far. The data suggest that HIV-2 infection of nonhuman primates provides an acceptable animal model to investigate vaccination or specific immunotherapeutic procedures.

Animals↗
PubMed1989

Attitudes of French-Canadian university students toward use of condoms: a structural analysis.

164 French-Canadian university students took part in a study analyzing the factorial pattern of attitudes toward the use of condoms. A principal component analysis identified 7 factors, namely, positive general attitude toward use of condoms, contraceptive security, inhibition of sexual pleasure, inconvenience, embarrassment, responsibility, and lessening of physical pleasure.

Adult↗
PubMed1989

[T lymphocytes in the circulating blood and pleural fluid of patients with tuberculosis or cancer].

Inflammatory pleurisies in the adult are particularly rich in CD4 lymphocytes, capable of inducing and facilitating the immune reaction. The aim of this study was to determine the percentage of CD4 and CD8 lymphocytes in pleural fluid and blood in 13 patients with tuberculous pleurisy and 12 patients with pleural neoplasms, to establish the diagnostic value of this analysis. Independent of the etiology of the effusion there is a concentration of CD4 T lymphocytes in the pleural fluid compared to the blood (49.52 +/- 12.36% and 39.28 +/- 6.74%, respectively, p value less than 0.001). However, there was a similar concentration for the two types of disorders studied with 59.92 +/- 7.26% for tuberculous pleurisies and 45.83 +/- 6.26% for neoplastic effusions, thus this technique does not make the diagnostic orientation any clearer.

Adult↗
PubMed1989

The epidemiology of leukemias (past, present, future).

There are three periods of the history of the epidemiology of leukemias. The first period is characterized by 3 features: the description of the occupational leukemias (radiations, benzene) with more recently the war leukemias (Hiroshima), the leukemia induced by chemotherapy; the description of the leukemias of animals induced by viruses (chicken, mice and more over cats); and the concept of the geographical hematology. The second period may be called "Burkitt period" so important are the consequences of the discoveries made in Uganda. The third period is Japanese and American with the leukemias induced by the virus HTLV 1 and the recent extensions. Such is the past. The present is defined by strong data (diversity of causes, diversity of the combinations of causes, of the etiologic pluralism), and by persisting weaknesses (epidemiology, classification of leukemias). Three ways for the future: induction, prediction, and correlation with the hope of an efficient prevention.

Animals↗