The use of fentanyl-patch in dogs undergoing spinal surgery: plasma concentration and analgesic efficacy.

Objectives of this study were to evaluate plasma concentrations and analgesic efficacy of fentanyl administered transdermically in dogs undergoing spinal surgery. At the end of the surgery and before awakening, a fentanyl-patch was applied and was maintained in situ for 72 h. Blood samples were taken before the application of the patch, at 2, 4, 6, 8, 10, 12, 18, 24, 32, 40, 48, 60, and 72 h after application and then 2, 4, 6, 8, 10, and 12 h after its removal. Before each blood sampling, pain evaluation was carried out using the Glasgow pain score, appropriately modified. Plasma concentrations of fentanyl were determined using a specific immuno-enzymatic kit. In this study, the minimum analgesic plasma concentration (0.23 ng/mL) required to achieve analgesia in human and considered to apply also for dogs was reached in all animals. No animal showed pain in the range of 'intense pain'; in two cases, the level of the pain was slight or moderate. No undesired effects were found. Results suggest that the use of transdermic patches could represent a valid aid in pain therapy in small animals; in particular, it contributes to the postoperative well-being of patients undergoing major surgery.

A clonal cell line (BME-UV1) as a possible model to study bovine mammary epithelial metabolism: metabolism and cytotoxicity of aflatoxin B1.

Despite the toxicological risks to which humans and animals are exposed due to the transfer of toxic xenobiotic metabolites into milk of domestic animals, studies on the metabolizing mechanisms occurring in ruminant mammary gland are totally lacking. To investigate the possible biotransformation capabilities of a bovine mammary epithelial cell line (BME-UV1), monolayers were exposed to aflatoxin B1 (AFB1--1.0-8.0 microM). Starting from 4 h of exposure, the hydroxylate metabolite aflatoxin M1 (AFM1) was detected in media by high performance liquid chromatography. AFM1 concentration increased linearly with time for 36-48 h and the percent biotransformation of AFB1 (2-4 microM) at 48 h was about 12-14%. Parallel cytotoxicity assays (neutral red uptake-NRU and MTT assays) were performed to investigate the possible interference of AFB1 cytotoxicity with cellular metabolism. MTT assay (from 24 h of cell exposure) and NRU assay (from 16 h of cell exposure) showed time-dependent and time/concentration-dependent decrease of cell viability, respectively, and the former assay being more successful at revealing cytotoxic effects (NRU: CC50 at 48 h = 12.00 +/- 2.66 microM; MTT: CC50 at 72 h = 20.42 +/- 7.30 microM). The results suggest that BME-UV1 cells express metabolizing enzymes having catalytic activity, thus representing a potential in vitro model for studying biotransformation in bovine mammary gland.

Investigation of the metabolic activity of a bovine mammary epithelial cell line (BME-UV1).

The metabolic activity of a mammary epithelial cell line (BME-UV1) was evaluated on monolayers exposed, in serum free medium, to different concentrations (2-4-8 muM) of aflatoxin B1 (AFB1), a mycotoxin eliminated into milk especially as hydroxylated metabolite aflatoxin M1 (AFM1). After 4, 8, 12, 24 h of treatment, a dose and time dependent production of AFM1 has been detected. As the enzymes involved in the hydroxylation of AFB1 in bovine hepatocytes are mainly CYP1A and CYP3A, the results suggest that BME-UV1 express CYP450 isoenzymes which metabolize AFB1 thus representing a potential model for the investigation of the metabolic activity of bovine mammary epithelial tissue.