口腔环境因素对血型链球菌和变形链球菌生长的影响：I.粘蛋白的影响

采用连续培养方法，以粘蛋白作为化学限定培养基中的限定性因子，观察血型链球菌（以下简称血链菌）和变形链球菌（以下简称变链菌）Ｉｎｇｂｒｉｔｔ（ｃ）的生长状态。结果显示变链菌不能生长于以粘蛋白作为唯一营养源的培养基中，而血链菌可以生长；两菌混合培养时的生长量均有所提高，表明两菌有协同降解粘蛋白作用。     

31例颌骨中心性巨细胞肉芽肿的临床病理研究

目的 观察分析颌骨中心性巨细胞肉芽肿(CGCG)的临床病理学特点及病变生物学行为问的关系，探讨颌骨CGCG的性质及诊断。方法 采用组织病理学方法，结合临床随访对比分析31例颌骨CGCG的临床病理学特点及其与病变性质的关系。结果 31例颌骨CGCG以30岁以下的女性多见，病变多见于下颌，X线表现无特异性。病变中的多核巨细胞(MGC)分布较不均匀，核数较少，以10～19个核多见，病变出血明显，纤维成分丰富，常有含铁血黄素沉积，骨及类骨质多见。比较病变复发组与非复发组问的临床病理学特点，结果提示差异无统计学意义。根据临床和X线特点病变分为侵袭组与非侵袭组，侵袭组与复发关系密切。结论 颌骨CGCG是一种非瘤性病变，在病变性质上有别于骨巨细胞瘤，其病理学特点在两者的鉴别上缺乏客观标准并且与其生物学行为无关，结合临床分析对治疗更加有意义。     

上皮根鞘细胞在牙骨质发育中的作用

目的：观察牙根发育中上皮根鞘细胞（Hertwig＇s epithelial root sheath,HERS）断裂后结局和增殖凋亡相关基因的表达,探讨上皮根鞘在牙根发育特别是牙骨质形成中的可能作用.方法：用TUNEL（ TdT- mediated - dUTP nick end labeling , TUNEL） 法原位细胞凋亡检测牙根发育中上皮根鞘细胞凋亡的情况.以细胞角蛋白14（cytokeratin 14）标记上皮根鞘细胞,追踪其断裂后结局.SP免疫组化法检测增殖细胞核抗原（proliferating cell nuclear antigen, PCNA ）和凋亡抑制基因Bcl-2在上皮根鞘细胞的表达.结果：牙冠形成后,内外釉上皮结合增殖形成HERS,此时呈PCNA表达阳性;牙根发育开始后,HERS呈Bcl-2阴性表达,在少量牙本质基质形成处,上皮根鞘细胞开始呈TUNEL阳性表达,之后HERS断裂,在其外侧可见成牙骨质细胞的形成,断裂的HERS细胞部分转入牙周膜形成上皮剩余（the epithelial rest of Malassez）,而细胞牙骨质形成中可见部分埋入细胞呈CK14阳性表达.结论： HERS细胞的凋亡可能会为成牙骨质细胞分化提供信号,部分HERS细胞可能参与牙骨质的形成.     

经皮肾镜术中不同憩室颈部处理方式治疗肾盏憩室结石的长期预后

目的: 比较经皮肾镜术中切开法与扩张法两种不同处理憩室颈部的方式治疗肾盏憩室结石的长期预后。方法: 选择2009年6月至2019年1月在北京大学人民医院经皮肾镜取石术治疗肾盏憩室结石患者的临床资料进行回顾性分析,记录年龄、性别、体重指数(body mass index,BMI)、美国麻醉师协会(American Society of Anesthesiology, ASA)分级和术前症状等患者基本情况,结石位置、大小等结石特征数据,皮肾通道长度、手术时长等手术相关数据,以及术后血红蛋白下降幅度、Clavien并发症分级、无石率等围手术期临床资料,并进行了5年以上的长期随访。结果: 53例患者纳入本研究,根据术中处理憩室颈部方式的不同分为扩张组(n=37)和切开组(n=16), 其中男性患者24例(45.3%), 女性29例(54.7%),平均年龄为(39.96±12.88)岁,大多数憩室结石位于肾上极(n=32,60.38%)和背侧(n=41,77.4%),以单发结石为主(n=36,67.9%),两组间人口学数据及结石特征数据除年龄及结石负荷外差异无统计学意义。45例(84.9%)患者术后达到无石状态,44例(83.0%)患者术后症状得到改善。术后12例患者失访,41例患者的平均随访时间为77个月。在术后1年时有1例出现复发。截止2021年3月,15例患者术后随访未满5年,剩余26例术后5年复发率为34.6%。两组患者围手术期并发症发生率、术后无石率及复发率差异均无统计学意义,术后5年复发率均较术后1年时明显升高,保持无石状态和残石状态患者所占比例明显下降。结论: 经皮肾镜处理憩室结石术中切开法和扩张法处理憩室颈部均可达到令人满意的术后无石率,术后5年时憩室结石复发率为30%~40%。     

Full-Length Genome Sequencing of SARS-CoV-2 Directly from Clinical and Environmental Samples Based on the Multiplex Polymerase Chain Reaction Method

The new coronavirus, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), is spreading worldwide with the number of confirmed cases increasing dramatically[1,2]. Coronaviruses have the largest genome among RNA viruses and have caused two major outbreaks[3,4]. The new coronavirus (SARS-CoV-2) is the third coronavirus spread globally in the past 17 years. According to the World Health Organization, SARS-CoV-2 has affected more than 155.6 millon patients in 222 countries as of 6 May 2021 and has become a major global health concern (https://www.who.int/emergencies/diseases/novel-coronavirus-2019).     

National Nutrition and Health Systematic Survey for Children 0-17 Years of Age in China

The main purpose of the National Nutrition and Health Systematic Survey for children 0-17 years of age in China (CNHSC) was to collect basic data on the nutrition, development, and health status for children in different regions across China using evidence-based, reliable, and cost-effective approaches. Children and their parents or guardians from seven regions (south, southwest, north, northwest, eastern, central, and northeast China) in China were recruited. A multi-stage stratified randomized sampling method was used. Two provinces were randomly sampled from each of the seven regions, from which one urban district and one rural country were also randomly sampled, resulting in a total of 28 survey counties/districts. Dietary surveys, health examinations, laboratory testing, and questionnaires were used to collect dietary intake, nutritional status, child development, and health status information. Nutrition, health, and lifestyle assessment of children and their parents was determined using the Knowledge Attitude Practice (KAP) survey. Greater than 100,000 children (38,000 children < 6 years of age and 66,000 children 6-17 years of age) completed the survey. The survey provided comprehensive data on child nutrition and health status for future studies and will serve as the basis for an integrated nutrition and health improvement strategies proposal for children in China.