In vivo and ex vivo effects of propofol on myocardial performance in rats with obstructive jaundice

BACKGROUND: Responsiveness of the 'jaundiced heart' to propofol is not completely understood. The purpose of this study was to evaluate the effect of propofol on myocardial performance in rats with obstructive jaundice. METHODS: Male Sprague-Dawley rats (n = 40) were randomly allocated into two groups, twenty underwent bile duct ligation (BDL), and 20 underwent a sham operation. Seven days after the surgery, propofol was administered in vivo and ex vivo (Langendorff preparations). Heart rate, left ventricular end-systolic pressure (LVESP) left ventricular end-diastolic pressure (LVEDP), and maximal rate for left ventricular pressure rise and decline (+/- dP/dtmax ) were measured to determine the influence of propofol on the cardiac function of rats. RESULTS: Impaired basal cardiac function was observed in the isolated BDL hearts, whereas in vivo indices of basal cardiac function (LVESP and +/- dP/dt) in vivo were significantly higher in rats that underwent BDL compared with controls. With low or intermediate concentrations of propofol, these indices of cardiac function were within the normal physiologic range in both groups, and responsiveness to propofol was unaffected by BDL. When the highest concentration of propofol was administrated, a significant decline in cardiac function was observed in the BDL group. CONCLUSIONS: In rats that underwent BDL, basal cardiac performance was better in vivo and worse ex vivo compared with controls. Low and intermediate concentrations of propofol did not appear to impair cardiac function in rats with obstructive jaundice.published_or_final_versio

Ceramide glycosylation and fatty acid hydroxylation influence serological reactivity in Trypanosoma cruzi glycosphingolipids.

Ceramide mono (CMH) or dihexoside (CDH) fractions from Trypanosoma cruzi (Dm28c clone) were identified as glucosyl and lactosylceramides containing non-hydroxylated fatty acids. The di-glycosylated form was much more efficiently recognized by sera from T. cruzi-immunized rabbits, indicating that glycosylation influences antigenicity. Fatty acid hydroxylation was also a determinant of serological reactivity, since an alpha-hydroxylated CMH, only present at the Y clone, was recognized by the hyperimmune sera. In summary, these data indicate that T. cruzi CMHs with non-hydroxylated fatty acids are unable to induce antibody responses in animal hosts, which is reverted by the addition of a sugar residue or an alpha-hydroxyl group