Machine learning to predict myocardial injury and death after non-cardiac surgery

Myocardial injury due to ischaemia within 30 days of non-cardiac surgery is prognostically relevant. We aimed to determine the discrimination, calibration, accuracy, sensitivity and specificity of single-layer and multiple-layer neural networks for myocardial injury and death within 30 postoperative days. We analysed data from 24,589 participants in the Vascular Events in Non-cardiac Surgery Patients Cohort Evaluation study. Validation was performed on a randomly selected subset of the study population. Discrimination for myocardial injury by single-layer vs. multiple-layer models generated areas (95%CI) under the receiver operating characteristic curve of: 0.70 (0.69–0.72) vs. 0.71 (0.70–0.73) with variables available before surgical referral, p < 0.001; 0.73 (0.72–0.75) vs. 0.75 (0.74–0.76) with additional variables available on admission, but before surgery, p < 0.001; and 0.76 (0.75–0.77) vs. 0.77 (0.76–0.78) with the addition of subsequent variables, p < 0.001. Discrimination for death by single-layer vs. multiple-layer models generated areas (95%CI) under the receiver operating characteristic curve of: 0.71 (0.66–0.76) vs. 0.74 (0.71–0.77) with variables available before surgical referral, p = 0.04; 0.78 (0.73–0.82) vs. 0.83 (0.79–0.86) with additional variables available on admission but before surgery, p = 0.01; and 0.87 (0.83–0.89) vs. 0.87 (0.85–0.90) with the addition of subsequent variables, p = 0.52. The accuracy of the multiple-layer model for myocardial injury and death with all variables was 70% and 89%, respectively.     

云南省三州(市)6～11岁城市流动儿童的忽视现状研究

目的 了解云南省三地区城市流动儿童的忽视现况及主要原因,为有效减少其发生制定干预措施提供科学依据。方法 根据经济及教育水平等因素,2020年9—12月采用多阶段分层整群抽样,抽取昆明市、大理州和临沧市3个地区为调查点,采用《中国城市儿童青少年忽视评价常模量表》,对1 193名学生进行相关调查。结果 云南省三地区6～11岁城市流动儿童总忽视率40.7%(486/1 193),其中城市流动儿童忽视率为40.80%(393/963);非城市流动儿童忽视率为40.4%(93/230)。城市流动儿童男童各层面忽视率大于女童,其中安全层面有统计学意义(χ²=4.417,P<0.05)。不同民族中除医疗层面外,汉族忽视率都高于少数民族,其中身体(χ²=6.963,P<0.05)和情感(χ²=6.850,P<0.05)差异有统计学意义。与云南省农村儿童、中国农村留守儿童、全国儿童相应指标比较,云南省城市流动儿童忽视度较低,差异有统计学意义(6~8岁t=20.281、19.153、13.616,P<0.001;9~11岁t=7.075、13.101、8.047,P<0.001)。结论 云南省三州(市)6~11岁城市流动儿童忽视情况较十年前有所缓解,针对流动儿童实施的相关政策效果逐步显现。家庭教育模式有所转变,“父母教育卷入”使“子女随父母进城务工”逐渐被“父母随子女进城读书”所替代,但是针对低龄流动儿童的社会融合和适应相关问题应持续关注;民族教育层面下儿童忽视率性别差异更小,学校与家庭教育应因地制宜,注重亲子参与。     

Comparison of quantitative susceptibility mapping methods on evaluating radiation-induced cerebral microbleeds and basal ganglia at 3T and 7T

Quantitative susceptibility mapping (QSM) has the potential for being a biomarker for various diseases because of its ability to measure tissue susceptibility related to iron deposition, myelin, and hemorrhage from the phase signal of a T₂*-weighted MRI. Despite its promise as a quantitative marker, QSM is faced with many challenges, including its dependence on preprocessing of the raw phase data, the relatively weak tissue signal, and the inherently ill posed relationship between the magnetic dipole and measured phase. The goal of this study was to evaluate the effects of background field removal and dipole inversion algorithms on noise characteristics, image uniformity, and structural contrast for cerebral microbleed (CMB) quantification at both 3T and 7T. We selected four widely used background phase removal and five dipole field inversion algorithms for QSM and applied them to volunteers and patients with CMBs, who were scanned at two different field strengths, with ground truth QSM reference calculated using multiple orientation scans. 7T MRI provided QSM images with lower noise than did 3T MRI. QSIP and VSHARP + iLSQR achieved the highest white matter homogeneity and vein contrast, with QSIP also providing the highest CMB contrast. Compared with ground truth COSMOS QSM images, overall good correlations between susceptibility values of dipole inversion algorithms and the COSMOS reference were observed in basal ganglia regions, with VSHARP + iLSQR achieving the susceptibility values most similar to COSMOS across all regions. This study can provide guidance for selecting the most appropriate QSM processing pipeline based on the application of interest and scanner field strength.     

Dectin-2受体介导宿主抵抗烟曲霉菌感染的研究

目的探讨C型凝集素受体Dectin-2在烟曲霉菌感染中的作用及机制。方法用紫外线灭活的烟曲霉菌膨胀态分生孢子刺激野生型(wild type, WT)和Dectin-2缺失(Clec4n-/-)小鼠骨髓来源的巨噬细胞(bone marrow derived macrophages, BMDMs)。刺激20min及40min后，利用Western印迹法检测BMDMs中脾酪氨酸激酶(spleen tyrosine kinase, Syk)和核转录因子κB抑制因子(inhibitor-κB, IκBα)的磷酸化水平。刺激16h后，利用酶联免疫吸附法(enzyme-linked immunosorbent assay, ELISA)检测BMDMs细胞上清液中IL-6、TNF-α和IL-12p40的水平。另一方面，利用压舌感染的方法在WT和Clec4n-/-小鼠中构建烟曲霉菌肺部感染模型。感染2d后，统计小鼠整个肺脏荷菌量，并检测肺脏匀浆液中IL-6和IL-12p40水平。结果体外试验提示，烟曲霉菌刺激后，Dectin-2缺失的BMDMs中Syk和IκBα的磷酸化水平及IL-6、TNF-α和IL-12p40水平显著下降(P＜0.05)。体内试验发现，烟曲霉菌感染后，Dectin-2缺失小鼠中肺脏荷菌量显著升高(P＜0.05)，肺脏匀浆液内IL-6、IL-12p40水平显著降低(P＜0.05)。结论C型凝集素受体Dectin-2激活烟曲霉菌诱导的NF-κB信号通路并介导促炎细胞因子的产生，可在小鼠肺烟曲霉菌病动物模型中发挥保护性作用。     

Effect of iron deficiency without anaemia on days alive and out of hospital in patients undergoing valvular heart surgery

Comprehensive evidence regarding the treatment of non-anaemic iron deficiency in patients undergoing valvular heart surgery is lacking. This study aimed to investigate the association between non-anaemic iron deficiency and postoperative outcomes in these patients. We retrospectively analysed 321 patients of which 180 (56%) had iron deficiency (defined as serum ferritin < 100 ng.ml^-1 or < 300 ng.ml^-1 with transferrin saturation < 20%). While the iron-deficient group had lower pre-operative haemoglobin levels than the non-iron deficient group (median (IQR [range]) 134 (127–141 [120–172]) g.l^-1, 143 (133–150 [120–179]) g.l^-1, p = 0.001), there was no between-group difference in allogeneic red blood cell transfusion. Median (IQR [range]) days alive and out of hospital at postoperative day 90 was 1 day shorter in the iron-deficient group (80 (77–82 [9–85]) days vs. 81 (79–83 [0–85]) days, p = 0.026). In multivariable analysis, only cardiopulmonary bypass duration (p = 0.032) and intra-operative allogeneic red blood cell transfusion (p = 0.011) were significantly associated with reduced days alive and out of hospital at postoperative day 90. Iron deficiency did not exert any adverse influence on secondary outcomes except length of hospital stay. Our findings indicate that non-anaemic iron deficiency alone is not associated with adverse effects in patients undergoing valvular heart surgery when it does not translate into an increased risk of allogeneic transfusion.