Use of a colorimetric assay to evaluate the proliferation of canine mammary tumor cells exposed to propofol.

Drugs applied on human cancer cells can influence the rate of cell proliferation. The present study investigates the use of the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrasodium bromide (MTT) colorimetric assay to evaluate canine tumor cell proliferation after exposure to the injectable anesthetic, propofol. Primary (CIPp) and metastatic (CIPm) canine tubular adenocarcinoma cell lines were incubated with cell culture medium (control) or propofol (1, 5, and 10 µg/mL). The MTT assays were performed after 6 and 12 hours of exposure. Measurements of absorbance were obtained for each condition with a spectrophotometer and compared with controls using a 3-way analysis of variance (P < 0.05). An increased cell proliferation rate was observed in CIPp exposed to 5 and 10 µg/mL of propofol for 6 hours and 1, 5, and 10 µg/mL for 12 hours. No significant changes were observed in CIPm after 6 hours of exposure. All propofol concentrations decreased the cell proliferation rate in CIPm after 12 hours of exposure. The MTT assays showed that exposure of CIPp to propofol for 6 and 12 hours increased cell proliferation. A decrease in the CIPm proliferation rate was observed when propofol exposure lasted for 12 hours. Further studies are warranted to better understand the role of propofol on cancer cell proliferation.

Les médicaments appliqués sur les cellules cancéreuses humaines peuvent influencer la vitesse de prolifération cellulaire. La présente étude a examiné l'utilisation du test colorimétrique au bromure de 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tétrasodique (MTT) pour évaluer la prolifération de cellules tumorales canines après exposition à l'anesthésique injectable, propofol.Des lignées cellulaires primaires (CIPp) et métastasiques (CIPm) d'adénocarcinome tubulaire canin furent incubées avec du milieu de culture cellulaire (témoin) ou du propofol (1, 5, et 10 µg/mL). Les tests au MTT ont été effectués après 6 et 12 h d'exposition. Les mesures d'absorbance furent obtenues pour chaque condition à l'aide d'un spectrophotomètre et comparées aux témoins en utilisant une analyse de variance à trois facteurs (P < 0,05).Une augmentation de la vitesse de prolifération cellulaire fut observée chez les CIPp exposées à 5 et 10 µg/mL de propofol pour 6 h et à 1, 5, et 10 µg/mL pour 12 h. Aucun changement significatif ne fut observé chez les CIPm après 6 h d'exposition. Toutes les concentrations de propofol ont réduit la vitesse de prolifération cellulaire des CIPm après 12 h d'exposition.Les tests au MTT ont démontré que l'exposition de CIPp au propofol pour 6 et 12 h augmentait la prolifération cellulaire. Une réduction de la vitesse de prolifération des CIPm fut observée lorsque l'exposition au propofol durait 12 h. Des études supplémentaires sont nécessaires pour mieux comprendre le rôle du propofol sur la prolifération des cellules cancéreuses.(Traduit par Docteur Serge Messier).

Cardiopulmonary effects and anaesthesia recovery quality in horses anaesthetized with isoflurane and low-dose S-ketamine or medetomidine infusions.

OBJECTIVES: To evaluate cardiopulmonary effects and anaesthesia recovery quality in horses anaesthetized with isoflurane receiving medetomidine or S-ketamine infusions. STUDY DESIGN: Randomized, blinded, prospective clinical trial. ANIMALS: Fifty horses undergoing elective surgery. METHODS: After acepromazine and flunixin meglumine premedication, horses received medetomidine (7 µg kg-1 ) intravenously (IV). Anaesthesia was induced with midazolam and racemic ketamine (Med treatment group; 2.2 mg kg-1 ; n = 25) or S-ketamine (S-ket treatment group; 1.1 mg kg-1 ; n = 25) IV and maintained with isoflurane in oxygen/air and medetomidine (Med; 3.5 µg kg-1 hour-1 ) or S-ketamine (S-ket; 0.5 mg kg-1 hour-1 ). All horses were mechanically ventilated. Cardiopulmonary variables were evaluated. Isoflurane end-tidal concentrations (Fe'Iso), dobutamine requirements and thiopental boli were recorded. Plasma samples were collected in six horses to evaluate S-ketamine and S-norketamine concentrations. After surgery, medetomidine 2 µg kg-1 was administered IV. Four independent observers scored recovery using a visual analogue scale and a numerical rating scale. RESULTS: Both groups required similar mean Fe'Iso (1%). However, S-ket horses needed more thiopental boli. Median intraoperative cardiac index values were higher with S-ket (4.5 L minute-1  m-2 ) than Med (3.9 L minute-1  m-2 ). Overall, there were no differences in heart rate, blood pressure or dobutamine requirements; however, horses in S-ket showed higher heart rate values at 30 minutes after anaesthesia induction. Compared with Med horses, S-ket horses showed decreased PaO2 and increased pulmonary venous admixture values estimated with the Fshunt calculation. Recoveries were shorter and of poorer quality with S-ket. During infusion, S-ketamine and S-norketamine plasma concentrations lay in the ranges of 0.209-0.917 µg mL-1 and 0.250-0.723 µg mL-1 , respectively. CONCLUSIONS AND CLINICAL RELEVANCE: Despite the higher intraoperative cardiac index with S-ket, both protocols were considered to provide acceptable cardiovascular function. However, recovery quality was significantly better in the Med group.