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Biomedical subjects

C Favier

Publications and source records attributed to C Favier.

At least 19 recordsLinked to original sources

Defective RNA packaging is responsible for low transduction efficiency of CAEV-based vectors.

Replication defective retroviral vectors are regularly used for transfer and expression of exogenous genes into dividing cells and in animals. Since lentiviruses are able to infect terminally differentiated and non-dividing cells, their use to produce replication defective vectors may overcome this limitation. We developed two replication-defective lentiviral vectors based on the genome of Caprine Arthritis Encephalitis Virus (CAEV). The first vector (pBNL2) carries the neo and lacZ marker genes. Neo gene is expressed from a genomic RNA and lacZ gene from a subgenomic RNA. The second vector (pCSHL) carries a single fusion gene encoding both phleomycin resistance and beta-galactosidase activity. Replication-competent CAEV was used as helper virus to provide the viral proteins for transcomplementation of these vectors. Our data demonstrated that the genomes of both vectors were packaged into CAEV virions and transduced into goat synovial membrane cells following infection. However, the vector titers remained 3 to 4 logs lower than those of CAEV. Further analysis showed a lack of accumulation of unspliced pBNL2 RNA into the cytoplasm of producer cells resulting in the packaging of pBNL2 sub-genomic RNA only. In contrast, RNA produced from pCSHL vector was correctly transported to the cytoplasm and more efficiently packaged than the pBNL2 sub-genomic RNA as revealed by slot-blot and quantitative RT/PCR analyses. However this higher packaging efficiency of pCSHL genome did not result in a higher transduction efficiency of lacZ gene.

Animals

Fecal beta-D-galactosidase production and Bifidobacteria are decreased in Crohn's disease.

Digestive bacterial microflora play a major role in the pathogenesis of Crohn's disease (CD). Bacterial enzyme activities, especially beta-D-galactosidase, are decreased in fecal extracts from CD patients. We hypothesized that an alteration of the colonic flora might be responsible for this decrease. Indeed, we demonstrate that beta-D-galactosidase production in supernates of anaerobic cultures was significantly (P < 0.01) reduced in feces from patients with active Crohn's disease (N = 7), when compared to healthy controls (N = 8). Therefore using X-gal and selective media, we enumerated bacteria able to release beta-D-galactosidase in feces from patients with active (N = 16) or quiescent disease (N = 5) and healthy controls (N = 14). Bifidobacteria numbers were significantly reduced in patients (P < 0.01 for active; P < 0.02 for quiescent disease) whereas Bacteroides and Lactobacilli counts remained unchanged. beta-D-Galactosidase activity and Bifidobacteria counts were significantly correlated (P < 0.03). Bifidobacteria are regarded as beneficial for the host. The reduction in Bifidobacteria is responsible for decreased beta-D-galactosidase activity. Thus oral administration of prebiotics that promote their growth might have potential therapeutic interest.

Adolescent

Hypokalaemia related to acute chloroquine ingestion.

Large doses of chloroquine can cause poisoning. Our aim was to determine the possible relation between the plasma potassium concentration on admission with the severity of acute chloroquine poisoning and to assess the mechanism of chloroquine-induced hypokalaemia. We conducted a retrospective study of 191 consecutive cases. The main data included the occurrence of vomiting before admission, plasma, and urinary potassium concentration at admission, whole blood chloroquine concentration on admission, haemodynamic parameters and ECG, administration of catecholamines and outcome. Mean blood chloroquine level was 20.1 mumol/L (SD 14.3) (therapeutic level < or = 6 mumol/L). Mean plasma potassium concentration was 3.0 mmol/L (0.8) and was lower in the subjects who died than in those who survived (p = 0.0003). Plasma potassium varied directly with the systolic blood pressure and inversely with the QRS and QT. Plasma potassium varied inversely with the blood chloroquine (p = 0.0001; tau = -0.42). Acute chloroquine intoxication is responsible for a hypokalaemia which correlates with the gravity of the intoxication and may be due to a transport-dependent mechanism. Plasma potassium concentrations should be carefully observed, particularly among patients who also receive catecholamine infusions. We should keep in mind, however, that overzealous repletion invokes the risk of subsequent hyperkalaemia and thus should be avoided.

Acute Disease

Bacterial enzymes used for colon-specific drug delivery are decreased in active Crohn's disease.

Enzymes produced by colonic microflora have been proposed for triggering local delivery of antiinflammatory azo-bond drugs and prodrugs to the colon. This approach could be advantageous in steroid treatment of inflammatory bowel diseases, thus sparing steroids' side effects. We recently demonstrated that the metabolic activity of digestive flora, assessed on the activity of fecal glycosidases, was decreased in patients with active Crohn's disease. In the present study, the azoreductase activity in feces of 14 patients with active Crohn's disease was decreased (11.39 +/- 7.93 mU/g F) as compared with 12 healthy subjects (51.13 +/- 21.39 mU/g F). beta-D-Glucosidase and beta-D-glucuronidase activities in fecal homogenates incubated under anaerobic conditions were also decreased in patients. These data bring into question the therapeutic usefulness for those patients of azo-bond drugs and glycoside prodrugs. They could explain the therapeutic failure of some of those drugs in active ileocolic and colic Crohn's disease.

Adult

Different mechanism for insulin induced and contraction induced increases in skeletal muscle glucose uptake.

Glucose facilitated diffusion into cells depends on concentration gradients between intracellular and extracellular spaces and can be modified by several factors such as insulin and contractions. Calmodulin participates in the insulin induced recruitment of vesicles containing glucose transporter molecules and its inhibition by trifluoperazine blocks insulin increases in glucose uptake. In the present study we tested if calmodulin inhibition with trifluoperazine blocks hindlimb muscle glucose uptake increase induced by contractions. Trifluoperazine does not inhibit exercise induced increases in glucose uptake; therefore, the mechanisms by which insulin and functional activity increase glucose uptake are different.

Animals

Surimi and native codfish contain a common allergen identified as a 63-kDa protein.

We have compared the allergenicity of codfish and surimi (prepared from codfish) by skin testing, specific IgE-RIA, and leukocyte histamine release (LHR) in six fish-allergic patients. Prick tests were positive for codfish and, to a lesser extent, surimi. The percentages of labeled anti-IgE bound to surimi-Sepharose were 1.55 +/- 0.19% and 3-6% with control and patient sera, respectively. Inhibition of the surimi protein-Sepharose IgE-RIA was greatest (80%) at protein concentrations of 13.4 and 408.5 micrograms/ml for codfish and surimi extract, respectively. The allergenic protein was isolated by gel filtration and subjected to SDS-PAGE. The eluate from codfish contained several proteins ranging from 13 to 63 kDa, while the eluate from surimi contained a single 63-kDa protein. It was concluded that surimi contained a single allergenic protein.

Adolescent

[Differentiation of glucidolytic mycoplasmas isolated from goats by the API 50 CH system and electrophoresis].

Carbohydrate metabolism of 62 glucidolytic strains of mycoplasma belonging to 4 species (M ovipneumoniae, M putrefaciens, M mycoides, M capricolum) has been studied using the API 50 Ch system for bacterial identification. This microtechnique and colony aspect were relevant in distinguishing M ovipneumoniae and M putrefaciens from the group M mycoides and M capricolum isolated from goats, but still presented a lack of specificity in distinguishing M mycoides from M capricolum. Similar results were obtained when the mycoplasma strains were tested by electrophoresis.

Animals

[Responses of kids to monocytes infected in vitro by the caprine arthritis-encephalitis virus].

Retroviruses from small ruminants are spread between susceptible animals by mononuclear phagocytes which are also virus targets. Young seronegative goats were inoculated with in vitro infected monocytes producing caprine arthritis encephalitis virus (10(5) cells/animal) by intravenous route corresponding to 10(5) syncytia forming units. After 3 months the same goats received dexamethasone treatment (5 mg/animal each 2 days over a 10-day period). The observed immune response differed if the animal was infected with its own cells or with homologous cells. Before dexamethasone treatment, antibody production evaluated by gel precipitation, ELISA or western blot was delayed in autologous by comparison with homologous conditions. After dexamethasone treatment, the appearance of infectious monocytes in blood and subsequent arthritis were observed in all animals in homologous conditions and only in 1 animal out of 3 in autologous conditions. Host reaction to the infected cells determines virus expression at the time of contamination.

Animals

[Nasal and pulmonary flora in the goat].

On the basis of bacteriological examinations carried out on 75 intranasal swabs and 80 goat lung punctures, aerobic, aero-anaerobic respiratory microbes and mycoplasma were studied. Mycoplasma ovipneumoniae was isolated both from nasal flora (37%) and from the lungs (27.5%) as well as Pasteurella spp which accounted respectively for 24% and 12.5%. The nasal flora are characterised by the presence of a Gram-negative strain included in the genus Moraxella and connected with Moraxella bovis species.

Animals

[Evaluation of a new antiemetic, alizapride, in cancerology (author's transl)].

The antiemetic effect of alizapride was evaluated in 50 patients with advanced cancer undergoing chemotherapy with cis-platinum. Our results suggest that alizapride, in a dose of 800 or 900 mg, significantly alleviates nausea and emesis. In a preliminary study, we had established that, without antiemetic therapy, the same patients all suffered from emesis. On the whole, alizapride was well tolerated ; no major side-effects were recorded.

Adult

[Recording of the cardiac magnetic field. Technical considerations and initial results in hospital practice].

Recording the magnetic field of the heart poses enormous technical problems. Whatever type of captor is used, the parasite magnetic fields are 11000x more powerful than those of cardiac origin, and must be excluded. It is for this reason that magnetocardiography has remained a laboratory technique until the last few years. The authors present an induction magnetocardiograph whose specifications make it suitable for use in hospital practice. Thanks to the selectivity of the captor, it is possible to produce magnetic plots of the thorax.

Electrocardiography