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Biomedical subjects

A Charbonnier

Publications and source records attributed to A Charbonnier.

At least 19 recordsLinked to original sources
PubMed2004

Tissue distribution of bovine spongiform encephalopathy agent in primates after intravenous or oral infection.

BACKGROUND: The disease-associated form of prion protein (PrP(res)) has been noted in lymphoreticular tissues in patients with variant Creutzfeldt-Jakob disease (vCJD). Thus, the disease could be transmitted iatrogenically by surgery or use of blood products. We aimed to assess transmissibility of the bovine spongiform encephalopathy (BSE) agent to primates by the intravenous route and study its tissue distribution compared with infection by the oral route. METHODS: Cynomolgus macaques were infected either intravenously or orally with brain homogenates from first-passage animals with BSE. They were clinically monitored for occurrence of neurological signs and killed humanely at the terminal stage of the disease. Brain, lymphoreticular tissues, digestive tract, and peripheral nerves were obtained and analysed by sandwich ELISA and immunohistochemistry for quantitative and qualitative assessment of their PrP(res) content. FINDINGS: Incubation periods after intravenous transmission of BSE were much shorter than after oral infection. We noted that PrP(res) was present in lymphoreticular tissues such as spleen and tonsils and in the entire gut from the duodenum to the rectum. In the gut, PrP(res) was present in Peyer's patches and in the enteric nervous system and nerve fibres of intestinal mucosa. Furthermore, PrP(res) was found in locomotor peripheral nerves and the autonomic nervous system. Amount of PrP(res) ranged from 0.02% to more than 10% of that recorded in brain. Distribution of PrP(res) was similar in animals infected by the intravenous or oral route. INTERPRETATION: Our findings suggest that the possible risk of vCJD linked to endoscopic procedures might be currently underestimated. Human iatrogenic vCJD cases infected intravenously raise the same public-health concerns as primary cases and need the same precautionary measures with respect to blood and tissue donations and surgical procedures.

Administration, Oral↗
PubMed1999

Human acute myeloblastic leukemia cells differentiate in vitro into mature dendritic cells and induce the differentiation of cytotoxic T cells against autologous leukemias.

An immune response is involved in the control of leukemias as demonstrated by allogeneic bone marrow transplantation, by the eradication of residual leukemic cells by cytotoxic T cells and finally by the identification of tumor antigens which are recognized by effector T cells. Dendritic cells (DC) are professional antigen-presenting cells (APC) able to present antigens in the context of co-stimulatory signals necessary for T cell activation. Although tumor cells may express tumor antigens, they are usually unable to elicit an immune response since they are devoid of co-stimulatory capacities. To overcome this problem, engineering tumors to provide APC function could potentially result in polyvalent immunization to multiple tumor antigens. We have tested the differentiation of AML-5 (monoblastic, promonocytic and monocytic) leukemia cells and demonstrated that eight out of the ten fresh human acute myeloid leukemia populations tested can differentiate in vitro into bona fide APC. Leukemic cells acquire in vitro DC morphology, mature DC markers such as CD83, the up-regulation of MHC and co-stimulatory molecules and the ability to produce IL-12 upon maturation, while retaining their characteristic caryotypic abnormalities. However, we could not obtain an immature DC phenotype. They also acquire the ability to induce the differentiation of allogeneic naive cord blood CD4 and CD8 T cells as well as resting autologous cytotoxic T cells. These results demonstrate that some tumor cells acquire APC phenotype and functions and can thereby induce a potent autologous immune response that will be a valuable tool for detection of new tumor antigens and for in vivo immunization.

Adolescent↗
PubMed1997

Immune reconstitution after blood cell transplantation.

Immune clinical events and pattern of recovery of total lymphocytes, T cells and CD4+/CD8+ T cell subsets, B cells and NK cells, were analysed after allogeneic blood cell transplantation (BCT) for 12 months following transplant (n = 33). Results were compared with immune recovery after allogeneic bone marrow transplantation (BMT) (n = 15) and autologous blood cell transplantation (n = 19). Rates of acute GVHD were comparable in the two allotransplantation groups. Fourteen out of 17 evaluable alloBCT group patients have presented an extensive cGVHD. Total T cell, CD4+T cells and CD56+NK cell reconstitution were improved in alloBCT group vs alloBMT group. CD4+/CD8+ ratio evolution were improved in alloBCT group vs alloBMT and autoBCT groups. These results confirm that rapid immune recovery is associated with allogeneic blood stem cell transplantation.

Adult↗
PubMed1990

Twenty-four-hour energy expenditure and basal metabolic rate measured in a whole-body indirect calorimeter in Gambian men.

By use of a respiration chamber, 24-hour energy expenditure (EE), diet-induced thermogenesis (DIT), and basal and sleeping EE were measured in 20 young rural Gambian men during the "hungry" season (weight, 60.8 +/- 1.4 kg) and in a group of 16 European men matched for body composition (weight, 66.9 +/- 1.9 kg). The 24-h EE was lower in Gambian than in European men (2047 +/- 46 vs 2635 +/- 74 kcal/d, p less than 0.001, respectively). Basal EE and sleeping EE were also lower in Gambian than in European men (1.05 +/- 0.02 vs 1.25 +/- 0.02 kcal/min and 1.0 +/- 0.02 vs 1.18 +/- 0.02 kcal/min, p less than 0.01, respectively). DIT was blunted in Gambian compared with European men (6.3 +/- 0.6% vs 12.1 +/- 0.5%, p less than 0.001 respectively). The net efficiency of walking was greater in Gambian than in European men (23.2 +/- 0.3% vs 20.1 +/- 0.4%, p less than 0.001, respectively). A low basal and sleeping EE, a reduced DIT, and a high work efficiency are important energy-sparing mechanisms in Gambian men, which allow them to cope with a marginal level of dietary intake during the hungry season.

Adult↗
PubMed1990

A whole body transportable indirect calorimeter for human use in the tropics.

A transportable, whole body indirect calorimeter, designed for use in the tropics, is described. The calorimeter was built to study energy expenditure of people having chronically or acutely low levels of food intake, and it will help to determine energy adaptations made by individuals with restricted food intake. The calorimeter comprises two units: a 27 m3 ventilated chamber connected to an office housing control and monitoring equipment. The system also allows the experimenter to assess the rate of energy expenditure by means of a ventilated hood or a baby respiration chamber. The incoming air flow rate is variable and is typically set at approximately 30 l/min. Carbon dioxide production (VCO2) and oxygen consumption (VO2) are continuously monitored by means of differential gas analysers via a computerized data acquisition unit. Gas production/consumption rates are measured with a delay of 80 s, the complete response to step changes in VCO2 or VO2 consumption being calculated over 15 min using the rate of change terms in the gas exchange equations. The total electrical power required for the whole system is 12 kW. The calorimeter has been functioning for nearly 4 years in a rural village of The Gambia during which ambient temperatures have ranged from 16 to 44 degrees C and dewpoints from -8 to 24 degrees C. The performance and accuracy of the calorimeter were tested using 20 per cent CO2 in N2 infusion and butane burning. Agreement between the theoretical and the measured values was found to be 99 per cent for VO2 and 100 per cent for VCO2 with a precision for both gases of +/- 10 ml/min over a 1-h period.

Calorimetry, Indirect↗
PubMed1977

[Initial trial of a new test for the evaluation of hepatocellular function: the TMB test].

The oral administration of 400 mg of trimethoxy 1-3-5-benzene or T.M.B. is normally followed by a high urinary excretion of dimethoxy, 1, 3, hydroxy 5 benzene and other metabolites mainly in the form of conjugates. Urinary excretion during the first 3 hours is strongly reduced in liver disease. By a simple blind test we showed that the test is positive in subclinical and laboratory-negative liver failure.

Adult↗