Objective To explore the protective effects of erythropoietin (EPO) on cardiomyocytes against hypoxia/reoxygenation (HR) injury. Method Isolated and cultured rat eardiomyocytes were subjected to 2-hour hypoxia followed by 1 hour reoxygenation to establish model of HR injury. Cardiomyocytes were randomly divided into 4 groups: sham group, HR group, HR + EPO-treated group (EPO 10 U/ml), and HR + EPO + UO126-treated group (U0126 10?mol/L). The concentration of lactate dehydrogenase (LDH) in culture medium was detected by automatic biochemical analyzer; viability of eardiomyocytes was measured by MTT assay; apoptosis ratio was determined by TUNEL technology and Annexin-V-FITC with flow cytometer (FCM); level of extracellular signal- regulated kinase 1/2 (ERK_(1/2)) and phospho-ERK_(1/2) were measured by Western-blot analysis. Results EPO significantly decreased the leakage of LDH, enhanced activity, reduced apoptosis ratio, and increased level of phospho-ERK_(1/2).However, the effects were blocked by U0126, an inhibitor of MAPK. Conclusions EPO has the protective effects on cardiomyocytes against HR injury possibly via the mechanism of activation of ERK_(1/2) and inhibition of apoptosis.

【Objective】 To determine the risk factors of urinary sepsis secondary to minimally invasive percutaneous nephrolithotomy (mPCNL) in patients with negative preoperative urine culture (UC). 【Methods】 A total of 274 patients with negative preoperative UC treated with mPCNL during Jan.2016 and Jun. 2021 were retrospectively analyzed. The incidence of urinary sepsis was observed, and the general data of patients with or without urinary sepsis after mPCNL were compared. logistic regression model was used to analyze the risk factors of urinary sepsis after mPCNL. 【Results】 Urinary sepsis occurred in 11 cases (4.01%). Univariate analysis showed that urinary sepsis was associated with gender, body mass index, stone load, diabetes, urine WBC ≥2+, urinary nitrite, procalcitonin, and operation time. Multivariate logistic regression analysis showed that the independent risk factors of urinary sepsis after mPCNL included diabetes (OR=2.34, 95%CI=1.051-5.43, P=0.037), stone load (OR=7.51, 95%CI=3.17-7.38, P=0.045), urine WBC≥2+ (OR=4.57, 95%CI=6.75-11.38, P=0.032), urinary nitrite positive (OR=6.45, 95%CI=0.93-26.87, P=0.028) and operation time≥120 min (OR=3.53, 95%CI=1.41-8.85, P=0.042). 【Conclusion】 Diabetes, stone load, urinary WBC ≥2+, positive urinary nitrite and operation time ≥120 minutes are the risk factors of urinary sepsis after mPCNL in patients with negative urine culture.