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Biomedical subjects

A Jouan

Publications and source records attributed to A Jouan.

At least 37 records · Page 2Linked to original sources
PubMed1994

Studies on mechanism of action of glycyrrhizin against hepatitis A virus replication in vitro.

Glycyrrhizin (GL) achieved a concentration-dependent inhibition of the replication of hepatitis A virus (HAV) in PLC/PRF/5 cells. GL has been shown to inhibit an early stage of the HAV replication. GL was not virucidal and had no measurable effect on the adsorption of [3H]uridine-labelled virions to cells. GL inhibited HAV penetration of the plasma membrane as measured by the amount of infective virus no longer neutralizable by specific antibody over time.

Antigens, Viral↗
PubMed1994

[Antiviral effect of recombinant interferon-alpha on hepatitis A virus replication in human liver cells].

Two recombinant interferons-alpha (IFNs-alpha) were assayed for their antiviral effect on hepatitis A virus (HAV) replication in the human hepatoma cell line PLC/PRF/5. IFN alpha-2a and IFN alpha-2b resulted in concentration-dependent inhibition of HAV antigen expression and HAV infectivity at non toxic concentrations. Their selectivity indices, calculated as the ratio of the dose that reduced the number of viable cells to 50% (CD50) to the effective dose that inhibited 50% of viral antigen expression (ED50) were > 1000. Recombinant IFN-alpha emerged, from the present study, as a promising candidate for chemotherapy of hepatitis A.

Dose-Response Relationship, Drug↗
PubMed1993

Immunoaffinity purification of an oxidase-activating cytosolic complex from bovine neutrophils.

An oxidase activating complex from the cytosol of bovine neutrophils was purified by immunoaffinity using a monoclonal antibody specific for the 67 kDa cytosolic factor of oxidase activation (p67) and assayed for production of superoxide O2- in a cell-free system. The complex comprised not only p67, but also the second cytosolic factor of 47 kDa (p47) in equivalent amounts. The p47-p67 complex showed a good oxidase activating potency when added to neutrophil membranes in the presence of GTP-gamma-S and arachidonic acid. A ras-related small G protein could not be immunodetected in the p47-p67 activating complex, indicating that the GTP required for oxidase activation in the cell free system bound to a protein that was either present in catalytic amounts in the cytosolic complex or present in sufficient amount in the membrane fraction.

Animals↗
PubMed1993

A generally applicable ELISA for the detection and quantitation of the cytosolic factors of NADPH-oxidase activation in neutrophils.

An enzyme-linked immunosorbent assay (ELISA) has been developed using polyclonal antibodies raised against two cytosolic proteins of 47 kDa (p47) and 67 kDa (p67) which behave as activation factors for the superoxide-generating NADPH oxidase of neutrophils at the onset of phagocytosis. These two proteins become associated with the NADPH oxidase complex during activation. This immunological technique has been used to follow the purification steps of p47 and p67. It allows the detection of very small amounts of cytosolic factors in a crude neutrophil extract. It is straightforward and much more sensitive (about 1000 times more) than the classical assay based on the use of a cell-free system of oxidase activation and production of superoxide anion. The percentages of p47 and p67 assessed by ELISA with respect to total cytosolic protein were estimated to amount to 0.13 and 0.20%, respectively. The described method has potential applications for the titration of the cytosolic factors of oxidase activation in autosomal recessive forms of chronic granulomatous disease.

Animals↗
PubMed1992

Purification and properties of a functional 47-kilodalton cytosolic factor required for NADPH-oxidase activation in bovine neutrophils.

A cytosolic factor of 47 kDa required for activation of the NADPH oxidase, and referred to as p47, has been purified in its functional form from the cytosol of resting bovine neutrophils. The purification was monitored by the determination of the activating potency of p47 in a cell-free system of oxidase activation. The recovery was around 10% and the purification factor greater than 1000. P47 was phosphorylated in vitro by protein kinase A and protein kinase C. [32P] labeled p47 was resolved by isoelectric focusing into two major labeled bands of pI 7.0 and 8.5. Polyclonal antibodies were used to demonstrate that p47 is localized specifically in the cytosol of resting neutrophils, and that, upon activation of neutrophils, p47 is translocated from the cytosol to the membrane.

Animals↗
PubMed1991

ADP-ribosylation of a small size GTP-binding protein in bovine neutrophils by the C3 exoenzyme of Clostridium botulinum and effect on the cell motility.

A 24-kDa G protein, ADP-ribosylable by exoenzyme C3 from Clostridium botulinum and therefore related to the rho family, was found to be abundantly present in human and bovine neutrophils, and preferentially located in cytosol. In human myeloid HL60 cells, the amount of C3 substrate increased during differentiation of the HL60 cells into granulocytes. The effect of exoenzyme C3 on different functions of bovine neutrophils, namely generation of O-2, degranulation and chemotaxis, has been tested, using electropermeabilized cells. Exoenzyme C3 hardly affected the respiratory burst and the degranulation. In contrast, it efficiently inhibited the spontaneous and chemoattractant-induced motility of the cells and disorganized the actin microfilament assembly.

Adenosine Diphosphate Ribose↗
PubMed1990

A study of digestive absorption in four cases of Down's syndrome. Down's syndrome, malnutrition, malabsorption, and Alzheimer's disease.

Many data suggest that patients with Down's syndrome (DS) suffer from digestive malabsorption. A fecal test of absorption (search for undigested meat fibers following the ingestion of a measured diet) was conducted in 4 patients with DS. The results point to malabsorption in these patients and support the hypothesis of malabsorption in DS. The etiology of probable malabsorption in DS is discussed. Data are presented suggesting that chronic malnutrition caused by malabsorption could be the cause of the neuropathologic signs of Alzheimer's disease occurring at or slightly before the fourth decade in all patients with DS.

Adult↗
PubMed1990

[Epidemic of Rift Valley fever in the Islamic republic of Mauritania. Geographic and ecological data].

During and after the Rift Valley Fever epidemic in southern mauritania, we conducted epidemiological inquiries in order to determine epidemic and epizootic areas. The epidemic area was divided into two different zones. The first was located along the right bank of the Senegal River, around the town of Rosso. The second was located near the town of Kaedi. This epidemic area was included within the epizootic area, which stretched to the south, between Rosso and Saint-Louis. Several ecological changes had occurred in the recent past including erection of dams on the Senegal River for irrigation, and heavier rainfall than during previous years.

Animals↗
PubMed1990

[Evaluation of indicators of health in the area of Trarza during the epidemic of Rift Valley fever in 1987].

Randomized epidemiological studies conducted inside the Rift Valley fever epidemic area permitted an estimate of the different epidemiological rates. For the town of Rosso, the total number of infected persons was estimated at 9,320, the total number of symptomatic diseases at 1,013 and the number of deaths at 47. The minimal number of deaths for the area which had access to the hospital was 232. The immunity rate in the town was 34.89% after the epidemic. The ELISA test was used to test human and animal IgG and IgM antibodies. Human samples were collected using the "confetti" technique. After the epizootic the incidence was 36.9% and the immunity was 70.06% for animals sampled in the town.

Animals↗
PubMed1989

[Neurologic and neurosensory forms of Rift Valley fever in Mauritania].

During and after a Rift Valley fever epidemic in Southern Mauritania, we observed 348 patients infected by RVF virus. 17 of them had encephalitis. These belonged to 2 groups, acute febrile forms with short duration and possibility of death, and sub-acute forms, with a longer duration and with sequelae. They were pure encephalitis, without clinical or biological meningeal signs. We also noticed 5 brutal ocular attacks, running very slowly, with sequelae.

Adult↗
PubMed1989

[Hemorrhagic forms of Rift Valley fever in Mauritania].

During and after a Rift Valley fever (RVF) epidemic in Southern Mauritania, we collected 600 clinical observations. 348 were confirmed to be RVF cases. Among the 5 clinical forms we observed, some are benign but others, especially those with hemorrhagic signs are serious. We observed 48 icterohemorrhagic forms with 25 deaths. An icterus was associated with hemorrhagic signs, varying from gingivorrhagia to abundant bleeding. Biological hepato-nephritis was always present in major hemorrhagic forms. Fulminant forms, spectacular and characteristic are excellent markers for epidemiological studies in the field.

Adult↗
PubMed1989

[Mild clinical forms of Rift Valley fever during the epidemic in Mauritania].

During and after a Rift Valley fever (RVF) epidemic in Southern Mauritania we collected 600 clinical observations. 348 were confirmed to be RVF cases. We described 5 major clinical aspects: mild, icteric, icterohemorrhagic, hemorrhagic and neurological forms. The first one is the most frequently seen with 42.8% of the cases at admission. Fever was associated with various pains (cephalalgia, myalgia, arthralgia) and an important asthenia. Inconsistently this syndrome was accompanied by epistaxis and conjunctival hyperemia. The icteric form, never described before, is an icterus occurring during evolution of a mild form. It represents 28.5% of total cases at admission. The great number of theses mild forms implies that they could be used as excellent markers for an epidemic emergence.

Adolescent↗
PubMed1989

[Development of a clinical and biological scoring system for the prognosis of Rift Valley fever].

With regard to an acute disease, Rift Valley fever, we tried to establish a prognostic score to help physicians to set prognosis and to choose a health management suitable in their context. Using clinical and biological data collected during the 1987 RVF epidemic in Southern Mauritania, we established a prognosis score card. Data analysis allows to prognosticate forms of possible severe evolution as an association of four syndromes: fever over 39 degrees, hemorrhagic syndrome, icterus and neurological signs. Using 12 clinical symptoms and 3 biological signs, it is possible to prognosticate cases with fatal evolution.

Disease Outbreaks↗
PubMed1989

[Epidemiology of Rift Valley fever in western Africa. I. Serologic survey in domestic ruminants of Burkina Faso].

A serosurvey of Rift valley fever virus infection has been conducted among 2,410 domestic ruminants (sheep, goats and cattle) from Burkina Faso in 1985, 1986 and 1987. An active circulation of virus was demonstrated and 26.7% of the total animal tested had Rift valley fever virus reacting antibodies. An epizootic was demonstrated retrospectively for 1987 and appears to correspond to the RVF outbreak observed in the same type of sahelian environment during the same year in Mauritania. Analogous ecoclimatic and environmental risk factors are discussed. Others phleboviruses such as Arumowot, Gordil, Saint-Floris, Gabek Forest and Odrenisrou seem to be active in some areas but no evidence of pathogenesis for domestic ruminants was demonstrated.

Animals↗
PubMed1988

Comparison between vertical parallel hole collimator and 30 degrees rotating slant hole collimator for assessing global and regional left ventricular function by radionuclide angiography.

Left ventricular ejection fraction (LVEF) and regional wall motion abnormalities were determined in 40 patients (30 with coronary artery disease and 10 with valvular heart disease) using equilibrium radionuclide angiography. Scintigraphic acquisitions were collected in random order with 2 different collimators as follows: in anterior face (AF), left anterior oblique (25 degrees-45 degrees LAO) and 70 degrees LAO, with a vertical parallel hole collimator (VTC), and in 25 degrees-45 degrees LAO and 65 degrees-80 degrees LAO with a 30 degrees rotating slant hole collimator (RSHC), with the slant of the collimator directed towards the cardiac apex in both projections. Results were compared to contrast ventriculography (CV) performed in the 30 degrees right anterior view (3 segments: anterior, apical, inferior) and in a 60 degrees left anterior oblique view (3 segments: septal, apical and lateral). Radionuclide LVEF in both series was closely correlated with contrast ventriculographic LVEF (r = 0.89, VTC vs CV and r = 0.87, RSHC vs CV, respectively). Regional wall motion analysis was only performed among the 30 patients suffering from coronary heart disease. Eight contrast angiographic studies were normal and 22 abnormal. Global sensitivity and specificity were 100% and 63% with the VTC (3 false positives) and 91% and 87% with the 30 degrees RSHC (2 false negatives and 1 false positive, P = ns). Agreement for the localisation of the regional wall motion abnormalities between CV and radionuclide angiography was 70.6% with the VTC and 71.2% with the RSHC (P = ns).(ABSTRACT TRUNCATED AT 250 WORDS)

Coronary Disease↗
PubMed1986

Comparative clinical study of a new 17D thermostable yellow fever vaccine.

The immunogenicity and the safety of a new heat-stable 17D yellow fever vaccine have been assessed in a randomized comparative study by reference to a non-stabilized vaccine preparation. Seronegative adults were used and 115 and 143 were given the heat-stable and the non-stabilized vaccine, respectively. Fifty two days after the immunization, haemagglutination inhibiting antibodies were found in 77.6 and 73.9% of the vaccinees, neutralizing antibodies in 99.3 and 100% of them. The percentage of seroconversion and the geometric mean of antibody titres were not significantly different. No complaints or adverse reactions in association with the vaccines were recorded. This study demonstrates the high immunogenicity of this new stabilized vaccine whose stability has already been proven.

Adult↗