The Brucellin skin test as a tool to discriminate false positive serological reactions in bovine brucellosis.

Three experiments were performed in order to assess the diagnostic value of the Brucellin allergic skin test (AST) in a brucellosis false positive serological reactions (FPSR) context. First, 1259 cattle from 20 Brucella-free herds in a FPSR area were tested twice with AST to estimate its specificity. Secondly, AST and serological tests (complement fixation test [CFT], tube agglutination test, dithiothreitol-microagglutination test and ELISA) sensitivities were evaluated on 111 cattle positive to the Rose Bengal test (RBT) belonging to 15 Brucella-infected herds. Thirdly, AST was used in a field trial to discriminate FPSR from true brucellosis reactions. AST specificity in non-vaccinated cattle was very high (99.83%; confidence interval 95% [CI95%]: 99.67-99.96%). Skin thickening 72 h post-injection was significantly higher on vaccinated cattle (1.42 vs 0.15 mm). In this sub-population, AST specificity decreased significantly to 78% (CI95%: 68-87%). Individual sensitivity of AST relative to Rose Bengal test was 64% (CI95%: 54-72%), while all infected herds were AST positive (n = 15). When associated with CFT, it detected 95% (CI95%: 90-98%) of the infected cattle. These results were consistent with the field trial. In a FPSR context, AST was more specific than RBT or CFT. Therefore, this test could be used at herd level as a confirmation test, on cattle non vaccinated against brucellosis.

Tissue distribution and elimination of [3H]levamisole in the rat after oral and intramuscular administration.

Total radioactivity and drug concentrations were determined in plasma, organs and excreta of male rats given a single oral or intramuscular dose (7.5 mg/kg) of [3H]levamisole. The anthelmintic drug was distributed mostly within the digestive contents after oral administration and in kidneys and liver after intramuscular injection. The parent drug accounted only for 32 to 45% of total radioactivity in plasma and it appeared metabolized in both urine and bile. The urine (0-72 h) contained 68-78% of the radioactive dose, as parent drug and other tritiated materials. The 4-hydroxylation of levamisole did not represent a major metabolic pathway of the drug in the rat.

Incidence of experimental cirrhosis on hepatic disposition of [3H] levamisole in rats.

Levamisole [phenyl-2 3H] was injected intravenously (4.7 mg kg-1) into anaesthetized controls and rats in which cirrhosis had been induced by a combination of carbon tetrachloride and phenobarbitone. The biliary excretion (6 h) of the parent drug and its metabolites formed a significant part of the administered dose. Although bile flow did not vary, biliary excretion of levamisole and metabolites were respectively increased and decreased in cirrhotic compared with control animals. These differences could be the result of cirrhosis-induced decrease in the hepatic biotransformation of levamisole and also to limited active carrier transport for the output of metabolites into bile canaliculi.