RESUMO
Background: Valepotriate is an active ingredient of valerian (Valeriana officinalis) with strong antioxidant activity that is effective for numerous cardiovascular diseases. Objective: The aim of this study was to investigate the effect of an active ingredient of V. officinalis extract on ischemia-reperfusion-induced cardiac injuries in male rats. Methods: Thirty-two male rats were subjected to ischemia for 40 minutes and reperfusion for five days. The rats were divided into 4 groups of 8 each; group 1 (control) was given normal saline, and groups 2-4 were gavaged with 0.2, 0.1, 0.05 mg/kg of valepotriate extract, respectively, and received extract (0.2 mg/kg ip) two weeks before ischemia induction. Results: Dichloromethane V. officinalis (valepotriate) extract exerted a protective effect against ischemia-reperfusion-induced injuries. So that infarct size and number of ventricular arrhythmia and ventricular escape beats decreased compared to the control group. Moreover, ST segment amplitude, QTC interval, and heart rate decreased in the injured hearts and serum levels of antioxidant enzymes glutathione peroxidase, catalase, and superoxide dismutase increased. Biochemical markers malondialdehyde and lactate dehydrogenase also decreased on day 5 after the onset of reperfusion. Conclusion: V. officinalis extract may have a protective effect against myocardial ischemia-reperfusion by producing antioxidant effects.
RESUMO
Integral representations for the solution of linear elliptic partial differential equations (PDEs) can be obtained using Green's theorem. However, these representations involve both the Dirichlet and the Neumann values on the boundary, and for a well-posed boundary-value problem (BVPs) one of these functions is unknown. A new transform method for solving BVPs for linear and integrable nonlinear PDEs usually referred to as the unified transform (or the Fokas transform) was introduced by the second author in the late Nineties. For linear elliptic PDEs, this method can be considered as the analogue of Green's function approach but now it is formulated in the complex Fourier plane instead of the physical plane. It employs two global relations also formulated in the Fourier plane which couple the Dirichlet and the Neumann boundary values. These relations can be used to characterize the unknown boundary values in terms of the given boundary data, yielding an elegant approach for determining the Dirichlet to Neumann map. The numerical implementation of the unified transform can be considered as the counterpart in the Fourier plane of the well-known boundary integral method which is formulated in the physical plane. For this implementation, one must choose (i) a suitable basis for expanding the unknown functions and (ii) an appropriate set of complex values, which we refer to as collocation points, at which to evaluate the global relations. Here, by employing a variety of examples we present simple guidelines of how the above choices can be made. Furthermore, we provide concrete rules for choosing the collocation points so that the condition number of the matrix of the associated linear system remains low.