The Mechanism of Redox Reaction between Palladium(II) Complex Ions and Potassium Formate in Acidic Aqueous Solution

The kinetics studies of redox reaction between palladium(II) chloride complex ions and potassium formate in acidic aqueous solutions was investigated. It was shown, that the reduction reaction of Pd(II) is selective in respect to Pd(II) complex structure. The kinetic of the process was monitored spectrophotometrically. The influence of chloride ions concentration, Pd(II) initial concentration, reductant concentration, ionic strength as well as the temperature were investigated in respect to the process dynamics. Arrhenius equation parameters were determined and are equal to 65.8 kJ/mol, and A = 1.12×1011 s-1

Effects of 4-Hydroxy-2-Nonenal, a Major Lipid Peroxidation-Derived Aldehyde, and N-Acetylcysteine on the Cyclooxygenase-2 Expression in Human Uterine Myometrium.

Background: Chorioamnionitis is one of the important causes of preterm labor. Preterm labor with chorioamnionitis is associated with oxidative stress. We reported that 4-hydroxy-2-nonenal (4-HNE), a major end product of oxidative fatty acid metabolism, is accumulated in the placenta with chorioamnionitis. The aim of this study was to confirm the effect of 4-HNE on cyclooxygenase-2 (COX-2) and prostaglandin (PG) induction in the uterine myometrial tissues. We also examined the effect of N-acetylcysteine (NAC) on 4-HNE-induced COX-2 expression. Methods: Uterine myometrial tissues were obtained from 5 patients. One of them underwent elective cesarean section without labor, and 4 of them underwent hysterectomy because of placental previa or atonic bleeding. We stimulated the uterine myometrial tissues with 4-HNE. In addition, the tissues were pretreated with NAC before 4-HNE treatment. The expression of COX-2 mRNA was observed by real-time PCR. PGE2 and prostacyclin release into the supernatants of the tissue cultures was measured by ELISA. Results: 4-HNE induced the COX-2 mRNA expression and PGE2 production in the uterine myometrial tissue culture in a dose-dependent and time-dependent manner. NAC inhibited 4-HNE-induced COX-2 expression. Conclusion: 4-HNE may play an important role in preterm labor. NAC might be protective against preterm labor under oxidative stress