一起学校耐药肺结核聚集性疫情的调查

目的 对北京市朝阳区某学校一起耐药肺结核疫情进行分析,为今后耐药结核病疫情的处置提供参考。方法 对病例进行流行病学调查,对病例密切接触者采用PPD试验、X线胸片和CT相结合的方式筛查。结果 2018年10月—2019年6月,该校共发生36例肺结核病例,发病率为4.5%。其中5例耐多药,3例耐利福平。36例病例分布在四个班,15a班27例、15b班4例、15c班2例、17d班3例。各班发病率分别为56.3%、8.3%、5.7%、7.1%,差异有统计学意义(P<0.01)。8例耐药病例中6例为15a班学生,占耐药病例总数的75.0%。经CT筛查68名密切接触者中确诊23例肺结核患者,检出率33.8%。结论 该起学校聚集性疫情为全国首起耐药肺结核聚集性疫情,首发病例未及时就医,传染源隐匿存在时间长,是导致该起疫情发生的主要原因。疫情处置中开展密切接触者筛查对于及时发现新病例非常重要。     

Hypertension is a risk factor for adverse outcomes in patients with coronavirus disease 2019: a cohort study

Abstract

Background

Comorbidities are commonly seen in patients with coronavirus disease 2019 (COVID-19), but the clinical implication is not yet well-delineated. We aim to characterize the prevalence and clinical implications of comorbidities in patients with COVID-19.     

个体化假体复合组织工程技术修复兔下颌骨缺损

目的研究快速成型（RP）技术辅助下制作的个体化假体复合珊瑚羟基磷灰石（CHA）、重组人骨形成蛋白2（rhBMP-2）修复兔下颌骨缺损的成骨效果。 方法以27只新西兰大白兔为实验对象，随机数字表法平均分成3组（每组9只），全部建立下颌骨连续性缺损模型，并在兔下颌骨缺损区分别植入个体化假体+自体骨（A组）、个体化假体+CHA（B组）、个体化假体+CHA+rhBMP-2（C组）。分别于术后4、12、24周3个时间点处死动物取材，进行大体标本观察，以及骨钙素（OC）、Ⅰ型胶原（COL-1）的免疫组化观察，分别比较各组修复骨缺损的能力，并对实验数据进行重复测量设计资料的单因素方差分析。 结果术后24周各组实验兔外形均对称，通过OC及COL-1的吸光度检测，骨缺损区均有大量新骨形成，A组（0.537 ± 0.010）、C组（0.530 ± 0.010）可见大量骨小梁及编织骨结构，缺损区的新骨OC、COL-1的免疫组化观察基本一致，差异无统计学意义（t = 0.007，P>0.05）；但A组强于B组（0.415 ± 0.009，t = 0.122，P<0.001）；C组也强于B组（t = 0.121，P<0.001），差异均有统计学意义。 结论在兔下颌骨缺损修复中，通过RP技术和组织工程技术相结合，CHA复合rhBMP-2后成骨能力明显增强，成骨效能肯定，为后期的临床应用提供可靠的实验基础。     

自发性高血压大鼠永久性脑缺血模型建立的研究

目的在比较自发性高血压大鼠(SHR)与同龄无高血压Wistar大鼠永久性大脑中动脉阻塞(pMCAO)后脑缺血损伤情况并初步分析其可能机制。方法雄性SHR和Wistar大鼠各30只分别随机分为:pMCAO模型6 h组、假手术6 h组、pMCAO模型24 h组、假手术24 h组和正常组(均n=6)。采用线栓法制作pMCAO模型,术后6、24 h对大鼠进行神经功能学评分后处死,制作脑冠状切片。术后6 h处死大鼠脑部切片行尼氏染色后在组织学层面上观察神经元损伤情况;术后24 h处死大鼠脑部切片行尼氏染色后计算脑梗死体积和水肿程度百分比。正常组脑部切片经苏木精-伊红染色后计算脑部小血管壁/腔比。结果术后6和24 h,不同品系大鼠神经功能学评分差异无统计学意义(P0.05);术后6 h尼氏染色示SHR神经元损伤重于Wistar大鼠。术后24 h SHR脑梗死体积百分比[(28.05±2.38)%]大于Wistar大鼠[(25.23±1.33)%],差异有统计学意义(P0.05)。两品系大鼠之间脑水肿程度差异无显著性。脑部小血管壁/腔比SHR[(11.46±3.74)%]较Wistar大鼠[(8.73±1.73)%]增大(P0.05)。结论 pMCAO术后SHR的脑缺血损伤程度重于Wistar大鼠,可能与高血压引起的脑侧支循环血管壁增厚、僵硬,自我调节能力降低有关。     

Assessment of toxicity using dehydrogenases activity and mathematical modeling

Dehydrogenase activity is frequently used to assess the general condition of microorganisms in soil and activated sludge. Many studies have investigated the inhibition of dehydrogenase activity by various compounds, including heavy metal ions. However, the time after which the measurements are carried out is often chosen arbitrarily. Thus, it can be difficult to estimate how the toxic effects of compounds vary during the reaction and when the maximum of the effect would be reached. Hence, the aim of this study was to create simple and useful mathematical model describing changes in dehydrogenase activity during exposure to substances that inactivate enzymes. Our model is based on the Lagergrens pseudo-first-order equation, the rate of chemical reactions, enzyme activity, and inactivation and was created to describe short-term changes in dehydrogenase activity. The main assumption of our model is that toxic substances cause irreversible inactivation of enzyme units. The model is able to predict the maximum direct toxic effect (MDTE) and the time to reach this maximum (T_MDTE). In order to validate our model, we present two examples: inactivation of dehydrogenase in microorganisms in soil and activated sludge. The model was applied successfully for cadmium and copper ions. Our results indicate that the predicted MDTE and T_MDTE are more appropriate than EC₅₀ and IC₅₀ for toxicity assessments, except for long exposure times.