Some azo dyes, including Sudans I–IV and Para Red, are genotoxic and may be biotransformed to cancerogenic aromatic amines. They are banned as food and feed additives, but their presence has been detected in food. Aromatic amines are also considered potentially toxic. Online EC–MS is a promising tool to study the transformation mechanisms of xenobiotics such as azo dyes. The aim of the study was to investigate emulation of how azo dyes are enzymatically transformed to amines with EC–MS. The reduction reactions of five azo dyes (Sudans I–IV and Para Red) were conducted using a glassy carbon working electrode and 0.1% formic acid in acetonitrile. Reduction results were compared with the literature and in silico to select preliminary candidates for metabolites. The LC-MS/MS method was used to confirm results obtained by electrochemical reactor. A limited number of pre-selected compounds were confirmed as azo dyes metabolites – aniline for Sudan I, aniline and 4-aminoazobenzene for Sudan III, o-toluidine for Sudan IV, and 4-nitroaniline for Para Red. No metabolites were found for Sudan II. Electrochemistry–mass spectrometry was successfully applied to azo dyes. This approach may be used to mimic the metabolism of azo dyes, and therefore predict products of biotransformation.

The objectives of this study were to determine the role of a fall in pre-calving body condition score (BCS) in postpartum metabolic status and reproductive outcomes, and gauge the indicativeness of blood metabolites during the transition period. Cows were grouped based on BCS loss between days −14 ±3 and 0 relative to calving. Cows that lost no BCS were the BCS control group (BCS-C), cows that lost 0.25 BCS points the low BCS loss group (BCS-L), and those that lost 0.5 points or more the high BCS loss (BCS-H) group. Blood was taken on days −14 ±3, 3, 14, and 30 ±4 for determination of comprehensive metabolic panel biomarker levels. Beta-hydroxybutyric acid (BHBA) levels were quantified on postpartum examination days. Vaginal discharge scores, ovarian activity on day 30 ±4, and subsequent fertility parameters were evaluated. The BCS-H cows had lower mean Ca concentrations before calving and on day 3, when the group’s BHBA and CK were higher (P < 0.05); on day 14 they had higher AST concentrations (P < 0.05). The BCS-L cows had greater bilirubin levels (P < 0.05). The BCS-H cows had lower cyclicity and higher endometritis rates. First service pregnancy rates were 50%, 50%, and 61.9%, open days 96.8, 95.75, and 89.2, and overall pregnancy rates 56.25%, 65%, and 80.95 % in the BCS-H, BCS-L, and BCS-C groups, respectively. Prepartum BCS loss of ≥ 0.5 points could be associated with Brown Swiss cow low Ca and BHBA concentrations early postpartum, and with subsequent uterine health and overall pregnancy rate. Prepartum Ca concentration might be a prognostic biomarker for postpartum metabolic status and reproductive outcomes.

OBJECTIVE To determine pharmacokinetics and pharmacodynamics after oral administration of a single dose of clopidogrel to horses. ANIMALS 6 healthy adult horses. PROCEDURES Blood samples were collected before and at various times up to 24 hours after oral administration of clopidogrel (2 mg/kg). Reactivity of platelets from each blood sample was determined by optical aggregometry and phosphorylation of vasodilator-stimulated phosphoprotein (VASP). Concentrations of clopidogrel and the clopidogrel active metabolite derivative (CAMD) were measured in each blood sample by use of liquid chromatography–tandem mass spectrometry, and pharmacokinetic parameters were determined with a noncompartmental model. RESULTS Compared with results for preadministration samples, platelet aggregation in response to 12.5μM ADP decreased significantly within 4 hours after clopidogrel administration for 5 of 6 horses. After 24 hours, platelet aggregation was identical to that measured before administration. Platelet aggregation in response to 25μM ADP was identical between samples obtained before and after administration. Phosphorylation of VASP in response to ADP (20μM) and prostaglandin E1 (3.3μM) was also unchanged by administration of clopidogrel. Time to maximum concentration of clopidogrel and CAMD was 0.54 and 0.71 hours, respectively, and calculated terminal-phase half-life of clopidogrel and CAMD was 1.81 and 0.97 hours, respectively. CONCLUSIONS AND CLINICAL RELEVANCE Clopidogrel or CAMD caused competitive inhibition of ADP-induced platelet aggregation during the first 24 hours after clopidogrel administration. Because CAMD was rapidly eliminated from horses, clopidogrel administration may be needed more frequently than in other species in which clopidogrel causes irreversible platelet inhibition.