Biomedical subjects
Publications and source records attributed to E Benoit.
The mammary elimination of four potentially toxic metabolites of Febantel has been investigated by HPLC methods in the cow after the administration of a 7,5 mg/kg single oral experimental dose of this anthelmintic. The total of the four metabolites is equal to about 0.4 ppm 12 hours after the treatment. The individual levels fall down under the detection limit between the third and the sixth milking.
The location of the intractable residues of 14C-ring labelled-albendazole has been investigated in the sheep. Numerous biochemical compounds have been isolated: pulmonary CO2, blood dextrose, glycogen, triglycerides, cholesterol, hemoglobin, plasmatic, cytosolic and microsomal proteins, nucleic acids . . . No incorporation into intermediary metabolisms has been put into evidence. On the contrary, a significant covalently bound radioactivity has been observed on hepatic and plasmatic proteins. No covalent binding to hepatic DNA seems to be produced.
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The metabolism of febantel has been investigated in the rat and the sheep. The general pathway seems to be similar in both species: ten urinary metabolites are the result of cyclisation, oxidation and/or hydrolysis process. Using synthetic samples, the embryotoxic study of all individual metabolites has been performed in the rat. Unchanged febantel and two other metabolites are responsible for teratogenic effects. A four steps toxogenic pathway is described which finally leads to the ultimate known teratogen: methyl (5-(phenylsulfinyl)-1H-benzimidazole-2-yl) carbamate. Metabolic similarities with other anthelmintics and residual consequences are discussed.
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Netobimin and albendazole were administered orally to camels (n = 5 + 5) at molecular equivalent dosages, 15.8 and 10.0 mg/kg body wt, respectively. The plasma profiles of the two main metabolites were investigated for 54 h by high performance liquid chromatography. The metabolism and the disposition of both anthelmintics in camels were similar to sheep rather than to cattle. These results indicate that netobimin and albendazole are likely to be excellent anthelmintics for camels.
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The purpose of this study was to compare characteristics and performances between single-phase (SP) and high-frequency (HF) generators for x-ray units dedicated to veterinary radiology practice. A 30-kW SP and a 30-kW high HF generator connected to a rotating anode x-ray tube were used for the study. Source-film distance, screen/film combination, and film processing were kept the same during the experiment. The mAs value yielding a similar film optical density of a stair step phantom, as assessed by a densitometer and a similar dose, as assessed by a solid state detector, was estimated for different kVp values. The ratio of the mAs used with the SP generator to the equivalent mAs used with the HF generator to produce similar film density or radiation dose was calculated. Subject contrast was measured for different kVp values as the relative difference in film optical density between two steps of the phantom. The waveform of the tube current was recorded for the two generators using an oscilloscope. Motion artifact was produced on a lateral radiograph of a canine tarsus using the two generators. Reproducibility was assessed by comparing the variances of film density measurements made on the central step of the phantom on 10 consecutive images produced with the two generators. mAs ratios (SP/HF) to obtain similar film optical density ranged from 2 (for 90kVp) to 2.5 (for 70 kVp), and mAs ratios to obtain similar radiation dose ranged from 1.2 (for 100 kVp) to 1.4 (for 70 kVp). Image contrast was slightly higher for the SP than for the HF generator. Current waveform for the SP generator was half-sinusoidal and it was almost continuous for the HF generator. Motion artifact appeared as blur for the HF generator and as several regularly placed images of the subject for the SP generator. Reproducibility was significantly better for the HF than for the SP generator (P = 0.047). It was concluded that the HF generator was approximately two times more efficient, had a better reproducibility, and produced images with a lower contrast than the SP generator. Motion artifact appears differently due to different current waveform.
Evidence based on thermal stability and enzyme inhibition data suggests that the sulfoxidation of the drug toltrazuril by rat liver microsomes is catalyzed by different cytochromes P-450. Pretreatment of rats by different inducers--phenobarbital, 3-methylcholanthrene, dexamethasone, and triacetyloleandomycin--results in a 2.1-, 2.6-, 2.9-, and 1.8-fold increase, respectively, in the rate of sulfoxidation. The highest increase (8.4-fold) was observed after treatment of microsomes from triacetyloleandomycin-treated animals by potassium ferricyanide. Castration and aging also modify the sulfoxidase activity. The relative rate of formation of the two toltrazuril enantiomers [(A)- and (B)-sulfoxides] depends on the source of the microsomes, suggesting that different cytochromes P-450 have different stereoselectivities.