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Biomedical subjects

C Chartier

Publications and source records attributed to C Chartier.

At least 55 records · Page 3Linked to original sources
PubMed1995

Chemoprophylaxis of Cryptosporidium parvum infection with paromomycin in kids and immunological study.

The anticryptosporidial activity of paromomycin, a natural antibiotic weakly absorbed when administered per os, was assessed in goat kids experimentally infected once via the oral route with 10(6) Cryptosporidium parvum oocysts. Paromomycin used prophylactically at a dose of 100 mg/kg of body weight per day from day-1 to day 10 (day 0 was the inoculation day) prevented infection during the period of drug administration. A delayed low infection was suggested by an antibody rise, but the infection developed below the microscopic detection limits. This low parasite development induced a partial immunity in kids, which reacted immunologically to a challenge on day 21 without symptoms or detectable oocyst shedding. So, paromomycin is a good candidate for field trials because it is prophylactically effective against experimental C. parvum infection and well tolerated by animals. This drug would be useful in an adapted form as an anticryptosporidial agent for neonatal ruminants.

Animals↗
PubMed1995

An efficient procedure to select and recover recombinant adenovirus vectors.

Adenoviruses are efficient gene transfer vectors for a variety of cell types. To date, the most widely used methods to construct recombinant adenoviruses involve either in vitro ligation or recombination between one-half of the virus genome, previously cloned in a plasmid vector and engineered to contain the desired expression cassette, and the other half of the virus genome prepared from virions. Although quite effective, these approaches produce viral progeny containing a mixture of recombinant and parental background virus. Thus the recovery of the recombinant virus can be difficult, especially when it grows more slowly than the parental virus. To improve selection and recovery of recombinant adenoviruses, we have constructed an adenovirus vector, AdTG6553, in which the E1 region has been replaced by the thymidine kinase (tk) gene of herpes simplex virus type 1. We show that infection of cells with AdTG6553 in the presence of the nucleoside analog ganciclovir (GCV) prevents viral replication. The conditional lethal phenotype introduced in AdTG6553 makes it a valuable tool to counter-select parental background virus in the presence of GCV and isolate replication-deficient recombinant adenoviruses in which the tk expression cassette has been replaced by a new gene.

Adenoviridae↗
PubMed1995

Individual fluctuations in efficacy of febantel against Muellerius capillaris in goats.

One hundred and eighty-seven dairy goats originating from 7 farms in western France were treated individually with febantel (probenzimidazole drug) at a dose rate of 5 mg/kg in spring 1991. Individual faecal samples were collected on d 0, 7 and 21 post-treatment and processed for counting first stage larvae of Muellerius capillaris (LPG: larvae per gram of faeces). Eggs of digestive tract strongyles were also counted on d 0 and 7 (EPG: eggs per gram of faeces). Blood samples were taken on d 0 to assess pepsinogen concentration related to abomasal damage caused by strongyle infection. The individual characteristics of the goats were recorded. The procedure was repeated on the same animals in autumn 1991. The faecal larval count reduction (FLCR) was mainly related to farm and season: farm 1 in the spring and farm 6 in the autumn showed a higher proportion of high responder (HR) goats (FLCR > 80%), whereas farm 3 exhibited a lower proportion of HR goats in the autumn. On the other hand, the characteristics of the goats (breed, physiological status, age, weight, presence or absence of wattles and horns) as well as the initial level of parasitism (LPG, EPG and pepsinogen concentration) all had a role which was limited or zero on the variability of response to treatment. Goats could not be individually categorized according to their response level because the FLCR values obtained in the spring were not repeated in the autumn, suggesting that other environmental parameters could be involved.

Animals↗
PubMed1994

Between goat-farm biological variability of the nematode Muellerius capillaris first-stage larvea. Influence of anthelmintic treatment.

Seven dairy-goat farms from the centerwest of france were investigated for morphology and ecology of first-stage larvae (L1) of Muellerius capillaris before and after treatment of goats with febantel, a probenzimidazole anthelmintic. The lengths, survivals at 20 and -20 degrees C, and infectivity of L1 to intermediate host Helix aspersa, were different between farms. The between farms differences in survivals were reduced after treatment of goats with febantel. The observed between farm differences in L1 did not seem to be related to farm characteristics (intensity of treatments, susceptibility to febantel, and intermediate host species).

Analysis of Variance↗
PubMed1994

Variability in susceptibility to anthelmintics of the lungworm Muellerius capillaris first-stage larvae. Relationship to dairy-goat farms and previous exposure to febantel treatment.

Seven dairy-goat farms, located in central, western France, were studied in order to assess the variability in susceptibility of the lungworm Muellerius capillaris first-stage larvae (L1) to 3 different anthelmintics in relation to farm origin, by means of motility tests. The motility tests were performed by mixing larval suspensions with pyrantel (PYR), thiabendazole (TBZ) or ivermectin (IVE) solutions (3 concentrations x 3 incubation durations). The same anthelmintic tests were repeated 7 and 21 d after febantel (probenzimidazole) treatment of the goats. Before the treatment of goats, the average ratio (x 100) of L1 motility compared with control were very different for the 3 anthelminthics: 44, 30 and 59, respectively for TBZ, PYR and IVE. The ratios of L1 motility were the same at days 7 and 21 after the treatment of goats. The susceptibility of L1 to anthelmintics varied a great deal from 1 farm to another when goats had not been previously treated, whereas L1s from the same farms were the same after treatment of goats. The occurrence of different motilities of L1 with the anthelmintic tests from 1 farm to another should be related to the existence of different populations of M capillaris. The L1 motilities were reduced after anthelmintic treatment of goats suggesting a temporary effect on populations of M capillaris females shedding L1.

Animals↗
PubMed1994

Anthelmintic treatments against digestive-tract nematodes in grazing dairy goats with high or low levels of milk production.

The effect of a regular anthelmintic treatment during the grazing period on milk production and milk composition was measured in a dairy goat farm. One month before turnout, 92 goats were given 10 mg.kg-1 febantel and then allocated to 2 equivalent groups according to their levels of milk production. The first group was given febantel monthly, the second group was kept as an untreated control. Parasitological, haematological and serological data were collected monthly from March to September. Milk production data were recorded from March to August, goats being dried up in September. Results of strongyle egg counts, serum inorganic phosphate concentrations and 4 necroscopic examinations indicated a low level of nematode infection composed almost exclusively with Trichostrongylus colubriformis in untreated goats. No significant changes in milk yield, fat and protein content were detected between treated and untreated groups. Moreover, the impact of monthly anthelmintic treatment on milk production was different depending on the initial level of milk yield. Anthelmintic treatment induced a 4-8% increase in milk production for goats with the highest milk yield at the start of the experiment, whereas no beneficial effects were recorded for goats with the lowest milk yield.

Analysis of Variance↗
PubMed1994

Absence of protection against Eimeria ninakohlyakimovae after primo-infection with E ovinoidalis in new-born kids.

One group of kids (n = 23) was given 2 x 10(5) oocysts of Eimeria ovinoidalis (sheep coccidia) at birth; a second group (n = 23) was kept as an uninoculated control. Body weights, E ninakohlyakimovae oocyst output and serum coccidial antibody levels were monitored up to 77-102 d of age. No significant difference in any of these parameters was seen between the 2 groups, suggesting that no immune response to E ovinoidalis inoculation occurred. These results could be relevant to the absence of development of the endogenous stages of E ovinoidalis in kids and/or to the mode of inoculation (moderate and not repeated).

Animals↗
PubMed1993

Comparison of the effects on milk production of concurrent infection with Haemonchus contortus and Trichostrongylus colubriformis in high- and low-producing dairy goats.

The impact of nematode parasitism of the digestive tract on milk output and milk quality was examined in dairy goats. In addition, the consequences of worm infection were compared in goats with different lactation performance (ie, with initial high or low milk production). Forty-eight goats in the second month of lactation were allotted equally to 2 groups. The first group was given 5,000 Haemonchus contortus and 20,000 Trichostrongylus colubriformis larvae. The 24 additional goats remained free of parasites. Parasitologic, serologic, and milk data were collected every 2 weeks for 5 months, and body condition of the goats was scored throughout the study. Results of strongyle egg count in feces, increase in pepsinogen values, and reduction in RBC count, PCV, and serum inorganic phosphate concentration indicated subclinical infection. This subclinical parasitism induced a decrease in body condition scoring and led to persistent decrease in milk yield, ranging from 2.5 to 10% reduction from control values. Changes in fat and protein contents were not detected. In contrast, the consequences of infection were more severe in the 6 goats with the highest milk production at the start of the study. Decrease in milk output ranged between 13.0 to 25.1%, and was associated with decrease in fat content. Comparison of the response to parasitism in the 6 goats with the highest lactation performance and the 6 goats with the lowest performance indicated differences between both subgroups. According to parasitologic and pathologic data, high-producer goats had less resistance and/or resilience to infection associated with more severe consequences on milk production.

Animals↗
PubMed1992

Gastrointestinal helminths and lungworms of French dairy goats: prevalence and geographical distribution in Poitou-Charentes.

A study was conducted on 81 dairy-goat farms in western France. Faecal samples were collected once and 31 culled goats were necropsied in order to assess their gastrointestinal and respiratory helminth species, their prevalences and the intensities of infection as well as their geographical distribution in six subregions of the surveyed area. Fifteen species of helminth were recovered. The most frequent were Muellerius capillaris, Trichostrongylus colubriformis and Teladorsagia circumcincta with a prevalence more than 90%. The two latter species represented respectively 50.9% and 30.2% of the total worm burden of the digestive tract. Other prevalent species were Haemonchus contortus, Strongyloides papillosus, Trichuris spp., Moniezia spp. and Dicrocoelium lanceolatum. The occurrence of Dicrocoelium lanceolatum was related to the presence of calcareous or alkaline soils and restricted to the south of the surveyed area. No area at particular risk was defined for the other helminth infections, probably because of the relative homogeneity in climatic and topographic conditions of the six agricultural regions.

Animals↗
PubMed1992

The promoter of the human cystic fibrosis transmembrane conductance regulator gene directing SV40 T antigen expression induces malignant proliferation of ependymal cells in transgenic mice.

Transgenic mice bearing a human cystic fibrosis transmembrane conductance regulator (CFTR) promoter-SV40 T antigen fusion transgene were generated in order to localize in vivo the potential oncogenesis linked to the tissue-specific activity of the promoter for the CFTR gene. Surprisingly, the only site of tumors resulting from expression of the reporter onc gene was ependymal cells lining the brain ventricles. SV40 T antigen expression in these cells led to a consistent pathology in the first weeks of age: ependymoma and consequent hydrocephaly. Tumor-derived cell lines were established, characterized and shown to originate from SV40 T antigen-induced ependymoma. No pathological alterations were found in other organs, such as lungs and pancreas, in which cystic fibrosis is pathologically manifest in humans. Such transgenic mice and derived cell lines may represent valid models for analysing (1) the role of SV40 T antigen in ependymoma formation and (2) CFTR function in ependymal cells.

Animals↗
PubMed1991

Assessment of mean oocyst count in groups of kids: litter, individual randomized and non-randomized fecal samplings.

A trial was conducted in six pens of kids visited five times monthly to compare different regimes of fecal sampling in order to assess average coccidial infection at a group level. In addition to individual fecal samplings of all the kids in the pen, giving the actual mean oocyst count, three sampling methods were performed: (i) individual sampling of three, five, seven, ten, 15, 20 or more animals according to the numbers of animals in the pen; (ii) sampling of feces in the litter; (iii) individual sampling of six kids, three with the poorest and three with the highest daily weight gain. Results indicated that drawing a random sample of ten kids was necessary to obtain a good estimation, with an accuracy of 25% in more than 90% of pens. Sampling of feces in the litter and individual sampling of six kids selected on daily weight gain considerations gave accurate estimation of the actual mean oocyst counts except in the case of high levels of infection. Further investigations would be needed to assess the diagnostic value of such sampling techniques whatever the coccidial infection level.

Age Factors↗
PubMed1991

[A new case of Mycobacterium bovis pulmonary tuberculosis in the dromedary (Camelus dromedarius) in Mauritania].

A case of pulmonary tuberculosis is described in a dromedary from Nouakchott (Mauritania). Gross lesions affected pulmonary parenchyma, diaphragmatic pleura, pericardium and regional lymph nodes: caseo-calcified nodules, miliary tubercles and haemorrhagic "pendeloques". Microscopically lesions were characterised by granulomatous tissue, epithelioid cells, necrotic material in the centre. No Langhans giant cells were seen. Mycobacterium bovis was isolated from these samples.

Animals↗