OBJECTIVETo investigate the changes of aldehyde dehydrogenase 2 (ALDH2) expression in H O inducedcardiomyocytes oxidative stress injury.

METHODSCultured H9C2 cardiomyocytes were exposed to H O -inducedoxidative stress and the effects of the ALDH2 agonist Alda-1 and ALDH2 inhibitor Daidzin were tested on the stress level ofthe exposed cells. MTT colorimetric assay was used to assess the cell viability after the treatments. The oxidative stress level inthe myocardial cells was detected using DHE fluorescence staining, and the activity and protein level of ALDH2 were detectedwith spectrophotometry and Western blotting.

RESULTSCompared with normal control cells, Alda-1 treatment did notsignificantly affect the cell viability, oxidative stress level, or ALDH2 activity and protein level. H O exposure significantlylowered the cell activity and ALDH2 activity and protein expression and increased the oxidative stress level; Alda-1 treatmentobvious antagonized the effects of H O . Blocking ALDH2 with Daidzin produced similar effects to H O exposure on theviability, oxidative stress level, and ALDH2 activity and expression in the myocardial cells.

CONCLUSIONSH O exposure lowersthe activity and reduces the protein expression of ALDH2 in cardiomyocyte H9C2 cells, and activation of ALDH2 can alleviateH O -induced oxidative stress in the cells.

Objective: To compare the clinical efficacy of visual dilated sheath combined with needle nephroscope percutaneous nephrolithotomy (PCNL) with traditional PCNL for renal calculi，so as to enhance the intraoperative safety and puncture accuracy. Methods: A retrospective analysis was conducted on 100 patients with renal calculi treated on hospital during Sep.2022 to Sep.2023.Based on the surgical approaches，patients were divided into the needle nephroscope group (PCNL with visual dilator sheath and needle nephroscope，n=52) and traditional group (traditional PCNL，n=48).Clinical characteristics，surgical parameters，and outcomes were compared between the two groups. Results: There were no significant differences between the two groups in baseline data，total operation time and hospital stay (P>0.05).The needle nephroscope group had a longer channel establishment time compared to the traditional group [20.0(17.0-22.0) min vs.16.0 (15.0-21.0) min，P=0.002]，but significantly shorter puncture time [2.0 (1.0-2.6) min vs. 2.8(2.0-3.5) min，P<0.001]，and fewer adjustments of the puncture needle (9.6% vs. 64.6%，P<0.001).The channel was successfully established on the first attempt in all patients in the needle nephroscope group，while only 41 of patients in the traditional group achieved success on the first attempt，6 cases needed 2 attempts，and 1 case needed 3 attempts.Postoperative complications were absent in the needle nephroscope group，whereas postoperative bleeding requiring interventional treatment occurred in 1 case in the traditional group.There was no significant difference in the first-stage stone-clearance rate between the two groups (88.4%vs. 85.4%，P=0.872). Conclusion: PCNL using a visual dilator sheath combined with a needle nephroscope achieves a comparable first-stage stone-clearance rate to traditional PCNL.However，it offers significant advantages in terms of shorter puncture time，fewer adjustments of the puncture needle，and lower postoperative complication rate.These findings suggest superior safety and precision，making it a valuable technique for clinical application.