Search

Background/Aims: Arterial stenosis activates the renin-angiotensin-aldosterone system subsequently resulting in renovascular hypertension (RVHT) and renal oxidative injury. We explored the effect of sodium thiosulfate (STS, Na2S2O3), a developed antioxidant in clinical trial, on RVHT-induced hypertension and renal oxidative injury in rats. Methods: We induced RVHT in male Wistar rats with bilaterally partial ligation of renal arteries in the 2-kidney 2-clip model. We evaluated the STS effect on RVHT-induced oxidative injury and apoptosis by a chemiluminescence amplification method, Western blot, and immunohistochemistry. Results: We found STS displayed a dose-dependent antioxidant H2O2 activity and adapted the maximal scavenging H2O2 activity of STS at the dosage of 0.1 g/kg intraperitoneally 3 times/week for 4 weeks in RVHT rats. RVHT induced a significant elevation of arterial blood pressure, blood reactive oxygen species amount, neutrophil infiltration, 4-HNE and NADPH oxidase gp91 expression, Bax/Bcl-2/poly(ADP-ribose) polymerase (PARP)-mediated apoptosis formation, blue Masson-stained fibrosis, and urinary protein level. STS treatment significantly reduced hypertension, oxidative stress, neutrophil infiltration, fibrosis, and Bax/Bcl-2/PARP-mediated apoptosis formation and depressed the urinary protein level in the RVHT models. Conclusion: Our results suggest that STS treatment could ameliorate RVHT hypertension and renal oxidative injury through antioxidant, antifibrotic, and antiapoptotic mechanisms.

The generation of a 3-D grid using FEM is very complex due to the "T" type intersection region of a high voltage (HV) SF/sub 6/ current transformer (CT). In this paper, the charge simulation method (CSM) based on the uniqueness theorem of static electric field is applied for solving a 3-D open boundary electric field of HV SF/sub 6/ CT. The coordinate transformation is employed. The equal potential and electric field strength distribution of different profiles are obtained and figured out, taking the effects of shielding covers and porcelain casing on the electric field distribution into consideration.

Taking the combined effects of porcelain insulation casing, the silicon rubber external insulation and floating shield on the electric field into account, the electric field has been calculated for three kinds of vacuum circuit breakers with different external insulation structures using the finite element method (FEM). The potential of floating shield has been well considered and calculated. Based on the computing results, the influences of floating shield and the silicon rubber insulation are analyzed. The theoretical basis for further optimization design of external silicon rubber and the development of outdoor vacuum circuit breaker is provided.