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J M Godeau

Publications and source records attributed to J M Godeau.

25 records · Page 2Linked to original sources
PubMedDate not supplied

In vitro inhibitory effect of SR 27417, a potent platelet-activating factor (PAF) receptor antagonist, on the PAF-induced bovine platelet aggregation.

The in vitro inhibitory effect of SR 27417, an antagonist of the platelet-activating factor (PAF) receptor, on PAF-induced platelet aggregation was studied in blood collected from seven healthy Friesien calves. Inhibitory effects of SR 27417 were determined at thirteen different concentrations (0.1-400 nM) by using the dose-response curves of PAF on calf platelet aggregation. In the presence of SR 27417, the maximal slopes of aggregation (%/min) induced by low and high concentrations of PAF were significantly different from the control values obtained without an antagonist at p < or = 0.05 and p < or = 0.01 respectively. In vitro PAF-induced calf platelet aggregation was dose-dependently inhibited by SR 27417. The drug inhibited PAF-induced platelet aggregation in a competitive reversible manner (pA2 = 10.46 +/- 2.36 mol x L(-1)). In conclusion, the results of our study showed that addition of SR 27417 to bovine platelet in vitro inhibits PAF-induced platelet aggregation.

Animals↗
PubMedDate not supplied

Some attempts to improve the nutritive value of urea for dairy cows. II. Its administration in a slightly soluble form: isobutylidene diurea (IBDU).

Isobutylidene diurea (IBDU) was tested against urea with regard to the ammonia release in the rumen, the amount and composition of the nitrogen fraction reaching the intestine, the nitrogen and energy balances and the performance of lactating cows. Maize silage was the basal feed in all experiments. The ammonia concentration in the rumen liquor was measured in two dry cows fitted with a permanent rumen cannula. The ammonia release was clearly restrained when IBDU was substituted for urea, and the peak values were of the same order as those found with soybean meal. Two dry cows fitted with a re-entrant cannula at 10 cm from the pylorus were fed with maize silage supplemented with increasing amounts of either urea or IBDU. The duodenal flow levelled off with urea, but it continued to rise with IBDU even when high amounts were added to the silage. However, a large fraction of this increase was in the form of ammonia, corresponding to 60% of the dietary nitrogen supplied by IBDU. The amount of non-ammonia nitrogen was also higher with IBDU. The nitrogen balance of lactating cows was not noticeably affected when IBDU instead of urea was added to the maize silage. In the same manner, the digestibility of the rations and their metabolizable energy supply were not significantly modified, and the milk productions were quite similar with the two N compounds, apart from the tendency to lower milk fat and milk protein productions.

Ammonia↗
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Quantitative determination of haptoglobin (HAP) in human and bovine sera by capillary zone electrophoresis (CZE).

This study describes an original assay for serum haptoglobin determination by measuring the capacity of human haptoglobin (hHAP) and bovine haptoglobin (bHAP) to bind haemoglobin (Hb) as established by capillary zone electrophoresis (CZE). This method involves the addition of Hb in excess to the serum and the separation of the HAP-Hb complexes from free haemoglobin by CZE. Protein migration was recorded at a wavelength of 415 nm which reveals Hb alone (free or bound), and the concentration of HAP was indirectly estimated by measuring bound Hb. Different CZE conditions and the peak migration time of Hb from various species (human, equine, bovine, canine) were investigated. The electrophoretic separation of free human Hb (hHb) in excess and the hHAP-hHb complex was fully achieved by CZE, allowing a quantitative determination of hHAP. However, bovine haemoglobin (bHb) bound to bHAP and free bHb were poorly separated under the same conditions. The best detachment between bHAP-Hb complexes and free Hb was only attained in the bovine sample by use of canine haemoglobin (cHb). CZE assays performed with cHb gave very close values to those of a classic photometric method which measured the peroxidase activity of the haptoglobin-cyanmethaemoglobin complexes (y = 1.0168x - 0.072; r2 = 0.97). CZE assay was fast (< 10 min), inexpensive, did not require the use of a specific antibody and was reproducible (coefficient of variation, CV 3.6%).

Animals↗
PubMedDate not supplied

Serological and biochemical follow-up in cattle naturally infected with Fasciola hepatica, and comparison with a climate model for predicting risks of fasciolosis.

Several biological parameters were measured in 31 heifers naturally infected with Fasciola hepatica during one grazing season in the Belgian Ardennes. A forecast model based on daily temperature used to assess the risk of fasciolosis was fitted to this assay. Cattle were turned out to two pastures. Each pasture was divided into two plots: one was treated with calcium cyanamide and the other was left untreated. The Lymnaea truncatula snails were counted on three different occasions. The results indicated a poor molluscicide efficiency. Body weight gains, anti-Fasciola antibody levels, faecal egg counts, levels of sorbitol dehydrogenase (SDH) and gamma-glutamyl transferase (gamma GT), packed cell volumes, white blood cells and differential leucocyte counts were determined monthly. No statistically significant difference was observed between animals from the two plots regardless of the recorded data. No correlation was found between body weight gains and other biological data. The sampling date had a significant effect on the antibody responses within a same group, and on the enzymatic levels for all groups combined. The forecast results were consistent with the recorded data. Temperature was a major bioclimatic constraint on the transmission of life cycle, and risk of infection occurred mainly in late spring (May/June) and in early September. Current results might be used to issue advice on the need for flukicide treatment of cattle. The indicators of the infection considered alone were useless and it is concluded that herd diagnosis of fasciolosis may rely on the rise of specific antibody levels, possibly associated with an increase in hepatic enzyme activities.

Animals↗