BACKGROUND AND PURPOSE:Arterial spin-labeling MR imaging permits safe, repeated CBF measurement. We investigated the potential and technical factors of arterial spin-labeling imaging in assessing cerebrovascular reactivity to acetazolamide.

The in-gel activity assay (IGA) is a powerful technique that uses enzymatic activity and compares intensities of detected bands in mitochondrial respiratory chain supercomplexes, and it is applicable to eukaryotic organisms. However, no IGA has been established for complex III because of the difficulty of access by ubiquinol, a substrate for complex III. Herein, we demonstrate that cytochrome c (Cyt c) showed peroxidase activity on IGA as a component of complexes III and IV. We used pre-incubation with sodium dodecyl sulfate (SDS) before IGA to loosen complexes in the gel after high-resolution clear native polyacrylamide gel electrophoresis (hrCN-PAGE), a refinement of blue native PAGE. The signals of IGA based on peroxidase activity were obtained using enhanced chemiluminescence solution. Then, the gel was directly used in western blotting or hrCN/SDS two-dimensional PAGE. Our findings indicate that IGA for Cyt c reflected the indirect activity of complexes III and IV.

Introduction: Imatinib is a tyrosine kinase inhibitor used for treating various types of cancers. The other tyrosine kinase inhibitors sunitinib and dasatinib have been reported to induce diastolic dysfunction; however, such information is lacking for imatinib. Methods: Exp. 1: Imatinib mesylate in doses of 1 and 10 mg/kg, i.v., were administered to the halothane-anesthetized dogs (n=4). Cardiovascular variables along with biomarkers reflecting myocardial injury were measured. Exp. 2: Mitochondria isolated from the rat heart (n=2) were incubated with tyrosine kinase inhibitors, of which effects on mitochondrial respiratory complexes were assessed. Results: Exp. 1: The low dose decreased the total peripheral vascular resistance with prolonging the isovolumic relaxation time, prolonged the QTc and J-T peak c, and increased AST and LDH. Moreover, the high dose suppressed the ventricular relaxation, increased the left ventricular end-diastolic volume, prolonged HV interval and increased CPK. Exp. 2: The activity of complex II were decreased by the inhibitors. Conclusions: Imatinib may induce myocardial injury, resulting in the left ventricular diastolic dysfunction, in which mitochondrial dysfunction might play an important role.

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