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Biomedical subjects

C Chastel

Publications and source records attributed to C Chastel.

At least 91 records · Page 5Linked to original sources
PubMed1988

[Pathogenicity of Spiroplasma sabaudiense (mollicute) for the cells (c6/36) of Aedes albopictus (Insecta: Diptera) in vitro].

An initial stock of Spiroplasma sabaudiense had been maintained in cell-free medium for 2-3 years. Subsequent passages in Leibovitz's medium L-15 in the presence of Aedes albopictus (C6/36) cells dramatically increased the pathogenicity of S. sabaudiense towards these cells. Cytopathogenicity included production of syncytia, an increase in the number of mitochondria and alteration of their morphology, vacuolisation and a reduction in the rate of growth. Cell lysis was associated with cytadsorption by spiroplasmas and was apparent following the third passage. At six days post-inoculation during the fourth and fifth passages, cell cultures had been totally destroyed by S. sabaudiense. The intra-cellular stage of S. sabaudiense is described and the literature pertaining to the pathogenicity of spiroplasmas for insects is reviewed.

Aedes↗
PubMed1988

[Uneven distribution of arboviruses transmitted by ticks in sea bird colonies north and south of France].

During an extensive virological survey (1977-1986), 187 strains of five different arboviruses were isolated from 7,117 ticks parasitising seabirds in Brittany and Normandy, whereas only one viral strain was obtained from 1,414 ticks collected from the Southern coasts of France and Corsica. Among the many ecological factors involved in virus circulation in the two areas, the unequal sizes of the seabird colonies may probably explain the unbalanced distribution of viruses.

Animals↗
PubMed1987

Combination therapy for dendritic keratitis with acyclovir and vidarabine.

We treated 32 patients with dendritic keratitis with a combination of acyclovir 3% ointment and vidarabine 3% ointment or acyclovir and placebo. Patients with acyclovir alone healed in an average time of 7.7 days, while patients on the combination healed in an average of 6 days. Only one patient in the acyclovir and vidarabine group had a healing time longer than 7 days, whereas six patients in the acyclovir and placebo group had healing times longer than 7 days. By the median test, this difference in healing times was statistically significant (p = 0.035), and the combination prevented cases of prolonged ulceration.

Acyclovir↗
PubMed1987

Mosquito spiroplasmas from France and their ecology.

Spiroplasmas have been isolated previously from a number of blood-sucking arthropods, including ticks, horseflies, and deerflies. More recently, spiroplasmas were isolated from mosquitoes from the USA, France, and Taiwan. Spiroplasmas isolated from mosquitoes from France belong to at least three serogroups and are serologically different from one of the Taiwan isolates, Sp2. Our Ar 1343 strain is the prototype of a new serogroup (XIII). During 3 consecutive years (1983-85), the ecology of these spiroplasmas was studied in different biotopes near, and in, the Isère River Valley in Savoia, France. A total of 23 strains was isolated from four species or groups of mosquitoes (Aedes sticticus/vexans, Ae. cantans/annulipes, Ae. cinereus/geminus and Coquillettidia richiardii). Spiroplasmas were isolated only from female mosquitoes and only during June and July. An as yet unidentified virus was also isolated from three mosquito pools, one of which yielded spiroplasmas. Spiroplasma viruses were not detected. Antibody to our Ar 1357 isolate was found in 4 of 20 sera from cows living in the areas studied, but not in sera from wild rodents or in sera from rabbit or pigeon sentinels. Finally, preliminary results are presented on the effects of experimental infection of Ae. aegypti with the Ar 1357 isolated (serogroup XXII).

Animals↗
PubMed1986

Characterization of orbiviruses of the Kemerovo serogroup: isolations and serological comparisons.

Nine Orbiviruses of the Kemerovo serogroup were isolated from ticks collected in seabird colonies situated in the U.K., Faeroe Islands, Norway, Morocco and California, U.S.A. Comparison by serological tests with previously reported members of the Kemerovo serogroup demonstrated that viruses isolated from the hard tick, Ixodes uriae, were members of the Great Island subgroup, whereas viruses from soft ticks, Argas monolakensis and Ornithodoros maritimus, belonged to the Chenuda subgroup. Members of the Chenuda group differed from the Great Island group in their ability to produce plaques in Xenopus cell cultures and in the time taken to produce clinical signs in infected mice.

Animals↗
PubMed1986

[Sensitivity to various antibiotics of spiroplasmas isolated from mosquitoes in France].

Spiroplasmas are helical mycoplasmas that play a significant role in plant diseases. They are also found in arthropods that are likely to bite humans, such as ticks and mosquitoes. These arthropods can act as vectors and therefore may be of epidemiologic significance. Furthermore, mainly on the grounds of morphologic evidence, spiroplasmas have been incriminated in the genesis of human Creutzfeld-Jacob disease. We recovered six strains of Spiroplasma sp. from 1927 female mosquitoes. In vitro susceptibility of each strain to the following antibiotics was studied: tetracycline, oxytetracycline, doxycycline, erythromycin, chloramphenicol, rifampin, kanamycin, gentamicin and pefloxacin. Minimal inhibitory concentrations (MICs) were determined by dilution in liquid SP4 medium using microtiter plates. Plates were incubated for 24 to 48 hours at 30 degrees C. The inoculum contained approximately 5 X 10(5) CFU/ml. Each of the six strains was found to be highly susceptible to tetracycline, oxytetracycline, doxycycline, erythromycin, chloramphenicol and pefloxacin (MICs less than or equal to 0.16 microgram/ml, 0.63 microgram/ml, 0.08 microgram/ml, 0.16 microgram/ml and 0.32 microgram/ml respectively). On the opposite, the strains exhibited resistance to rifampin and variable degrees of susceptibility to kanamycin (12.5 micrograms/ml less than MIC less than 50 micrograms/ml) and gentamicin (3.12 micrograms/ml less than MIC less than 50 micrograms/ml). From our results, spiroplasmas seem to have more or less the same susceptibility to antibiotics as mycoplasmas.

Animals↗
PubMed1986

Avalon virus, Sakhalin group (Nairovirus, Bunyaviridae) from the seabird tick Ixodes (Ceratixodes) uriae White 1852 in France.

Nine strains of Avalon virus were isolated from Ixodes uriae ticks collected in the Cape Sizun seabird reserve, Brittany, from 1979 to 1985, during a longitudinal study of consequences of tick-borne infections for kittiwakes (Rissa tridactyla). Avalon virus strains isolated in France proved difficult to study owing to the weak infectious titres they exhibited in suckling mice or cultured cells. However, some interesting data concerning the ecology of virus infection and the morphology of the virions were obtained and are discussed.

Animals↗
PubMed1986

[Hydrophilic contact lenses and pathogenic microorganisms].

A first study was conducted on 243 hydrophilic contact lenses: 65 were macroscopically abnormal and 100 were infected with fungi. Moreover on Sabouraud's medium with chloramphenicol, 30 bacterial strains were isolated of which 25 Pseudomonas sp. (10 Ps. cepacia) and 1 Serratia liquefaciens. Then a second study was conducted on 107 among the 243 lens solutions: the 50 of the B trade mark were spoiled with 12 X 10(7) bacteria/ml and the 57 of the C trade mark with 5 X 10(7) bacteria/ml. This quantitative bacterial difference was confirmed with a qualitative one: from B trade-mark 6 Pseudomonas aeruginosa strains were isolated and from C only one. The authors emphasize the importance of Ps. aeruginosa in corneal ulcers associated with contact lenses, of lens solution composition, and of preservative usefulness.

Bacteria↗
PubMed1986

Randomized study of minocycline + gentamicin compared with metronidazole + gentamicin for prophylaxis or treatment of mixed infections in abdominal surgery.

Seventy patients admitted for abdominal surgery requiring short-term perioperative prophylaxis were randomized to receive minocycline + gentamicin or metronidazole + gentamicin. Thirty patients were considered to be infected at the time of surgery and were treated with the same regimen. In the prophylactic cohort, one patient from each group developed postoperative fever. One patient receiving minocycline developed a wound infection. The overall infection rate was 2.6%. In the treatment cohort, it appeared that the patients receiving metronidazole had more severe underlying diseases than those receiving minocycline. Consequently, more postoperative non-infectious complications were observed in the former. Minocycline + gentamicin appeared at least as effective than metronidazole + gentamicin in preventing postoperative infectious complications associated with abdominal surgery or in treating intra-abdominal infections.

Abdomen↗
PubMed1985

The isolation of Meaban virus, a new Flavivirus from the seabird tick Ornithodoros (Alectorobius) maritimus in France.

Seven strains of a new Flavivirus, for which the name of Meaban virus is proposed, were isolated from the seabird tick Ornithodoros (A.) maritimus collected during 1981 and 1982 in nests of herring gulls (Larus argentatus) on islands of South Brittany, France. The new virus was compared serologically with 65 other flaviviruses including Tyuleniy virus and was found to be most closely related to, but different from Saumarez Reef virus, an agent previously isolated in Australia and Tasmania. Some general properties of Meaban virus are described and its antigenic relationships with other tick-borne flaviviruses associated with seabirds are discussed.

Animals↗
PubMed1985

Reovirus type 1 and small wild mammals in a mixed focus of virus infections in France.

During field studies of a natural focus of Eyach virus infection in Western France, reovirus type 1 was isolated from tissues of a field mouse, Apodemus sylvaticus L., caught in 1982. Serological survey carried out in the same area among 118 small wild vertebrates, mainly mammals, showed a wide-spread circulation of this agent in 1982 and 1983. Epidemiological consequences of such results are briefly discussed in terms of virus interactions.

Animal Diseases↗
PubMed1985

[Spiroplasmas and hematophagous arthropods; prospects in tropical pathology].

Spiroplasmas are original wall-free prokaryotes which exhibit motility and a helical shape although lacking any cell wall or motile apparatus. They are known by phytopathologists because some of them are responsible for severe arthropod-borne plant diseases, such as Spiroplasma citri, the etiologic agent of "citrus stubborn disease". Other spiroplasmas are pathogenic for a number of insects: drosophila, bees and beetles. More recently spiroplasmas were also isolated from ticks, mosquitoes, horse-flies and deer-flies opening a new chapter in medical pathology. These agents are of possible great significance in Tropical Medicine.

Animals↗