Objective To explore the relationship between intracellular concentration of arsenic trioxide (ATO) in ATO-resistant K562 cells (K562/AS2) and ATO resistance level.Methods The K562/AS2 cells were established by gradually increasing the concentration of ATO from the parental cell line,K562.Arsenic concentration was measured with atomic fluorescence photometry.Cell viability was assessed using MTT assay.Results At exposure to 1 μg/ml ATO for 24 h,48 h and 72 h,the arsenic concentration in the K562/S cells were all significantly higher than that in the K562/AS2 cells,(15.63± 0.42) μg/L vs 0 μg/L,(22.27±0.15) μg/L vs (3.51±0.12) μg/L and (24.31±0.21) μg/L vs (3.61±0.11) μg/L (P ＜ 0.05).With increasing concentration and the extension of incubation time,concentration of arsenic in cells was gradually increased (P ＜ 0.05),which increase quickly between 1 μg/ml and 2 μg/ml.The growth inhibition rate of K562/AS2 cells was also gradually increased (P ＜ 0.05),which increased quickly between 1 μg/ml and 2 μg/ml.Linear correlation analysis showed that when the K562/AS2 cells was exposed to ATO for 24 h,48 h and 72 h,respectively,the cell growth inhibition rates were positively correlated with the intracellular concentration of ATO.Conclusions Either increasing concentrations of ATO or prolonging the exposure time to ATO can increase intracellular concentration of ATO in ATO-resistant cells,and intracellular arsenic concentration is positively related to the cytotoxicity of ATO to K562/AS2 cells.Therefore,the sensitivity to ATO of ATOresistant K562 cells could be restored by increasing the intracellular concentration of ATO.

Objective:To explore the value of layer-specific strain technique in evaluating the changes of left ventricular myocardial systolic function in patients with aortic stenosis(AS).Methods:From January 2019 to March 2022, 90 AS patients with left ventricular ejection fraction (LVEF) ≥ 50% in Hunan Provincial People's Hospital were selected, including 30 mild AS patients, 30 moderate AS patients, and 30 severe AS patients. In addition, 30 health examinees in the same period were selected as the control group. The normal echocardiographic parameters of the control group and the AS groups with different degrees were compared. The global systolic peak longitudinal strain (GLS) and global circumferential strain (GCS) of the left ventricular three-layer myocardium were measured by the layer-specific strain technique, and the correlation between the strain parameters and the peak systolic velocity (Vmax) of the aortic valve was analyzed.Results:The levels of interventricular septal depth (IVSD), left ventricular posterior wall depth (LVPWD), mean pressure gradient (MPG), and Vmax in mild, moderate and severe AS group were higher than those in the control group (all P<0.05); the GLS of each layer of left ventricle in mild, moderate and severe AS group was lower than those in control group (all P<0.05); the GCS of each layer of left ventricle in moderate and severe AS group was lower than those in control group (all P<0.05). The GLS of left ventricular endocardium in moderate AS group was lower than those in mild AS group (all P<0.05); the GLS and GCS of left ventricular layers in severe AS group were lower than those in mild and moderate AS group (all P<0.05). In AS group, GLS and GCS in endocardium, middle layer and epicardium were negatively correlated with Vmax ( r=-0.716, -0.660, -0.669, P<0.001; r=-0.669, -0.686, -0.598, P<0.001). Conclusions:The layer-specific strain can reflect the changes of left ventricular myocardial function in patients with AS, and has certain application value.

Objective To observe the serum cortisol level in ischemic stroke patients with obstructive sleep apnea syndrome (OSAS),and discuss the influence factors and its correlation with severity of cerebral infarction.Methods Two hundred ischemic stroke patients with onset of 6 h to 3 weeks,admitted to our hospital from July 2015 to April 2017,were recruited;all patients were monitored with polysomnography.According to apnea hypopnea index (AHI),all patients were divided into ischemic stroke without OSAS group (AHI＜5/h,n=89) and ischemic stroke with OSAS group (AHI≥ 5/h,n=111).Moreover,according to AHI,patients from ischemic stroke with OSAS group were divided into three subgroups,namely,mild subgroup (5/h ≤AHI＜15/h),moderate subgroup (15/h ≤AHI＜30/h) and severe subgroup (AHI ≥30/h).According to National Institutes of Health Stroke Scale (NIHSS) scores,all subjects were divided into a group of NIHSS scores no more than 10 and a group of NIHSS scores＞10.The general clinical data,biochemical indices,early morning blood pressure,serum cortisol level and sleeping parameters were detected and compared among the groups,and the main factors affecting serum cortisol levels were identified by multivariate linear regression analysis.Results (1) The serum cortisol level in ischemic stroke with OSAS patients ([195.41±75.31] μg/L) was significantly higher than that of ischemic stroke without OSAS patients ([158.65±77.28] μg/L,P＜0.05);the serum cortisol level in ischemic stroke with mild OSAS subgroup ([227.32±75.12] μg/L) was significantly increased as compared with that in the ischemic stroke with moderate OSAS subgroup and ischemic stroke with severe OSAS subgroup ([191.27±71.50] μg/L and [175.21±75.13] μg/L,P＜0.05).(2) The serum cortisol level of group of NIHSS scores＞10 was significantly higher than that of group of NIHSS scores ≤ 10 (P＜0.05).(3)AHI,NIHSS scores,longest duration of apnea,and lowest blood oxygen saturation at night had significant effects on serum cortisol levels.Serum cortisol levels increased with AHI (β=89.984,95％CI:71.325-108.644,P=0.000) and NIHSS scores (β=0.923,95％CI:0.377-1.468,P=0.001),increased with the longest sleep apnea (β=0.804,95％CI:0.262-1.325,P=0.000),and decreased with the lowest blood oxygen saturation at night (β=-0.709,95％CI:-0.290--0.041,P=0.000).Conclusion The serum cortisol level in cerebral infarction patients with OSAS was increased,and the higher the severity of cerebral infarction and OSAS is,the higher the serum cortisol level is.