LBL结合PBL在物理诊断教学过程中的初步探索

目的:比较传统教学模式和问题教学法及二者结合教学法的不同优劣势,找出物理诊断学最佳教学方法。传统教学模式采用授课为主的教学法(lecture based learning,LBL),单单强调了教师的重要性,而忽视学生的主观能动性,不利于调动和培养学生自学和灵活运用所学知识的能力。问题教学法(Problem-based learning,PBL),其强调学生自身的主观能动性,弱化了教师在教学中的主体地位,学生有偏离教学主线的风险。因而如果将LBL与PBL有机结合在一起,将可能有利于提高学生的学习效率和学习效果。方法:选取97名全科医学本科学员,在物理诊断课程教学过程中,采用完全随机的方法分为2组,采用LBL教学方法组48人,采用LBL结合PBL教学方法组49人,通过分别对理论、实践分层打分,确定优秀、合格、不合格的比率,采用Mann-Whitney U检验最终评定2组教学方法的授课效果。结果:在理论考试中,2组学员在优秀、合格、不合格的分层评定上均无明显差异(P0.05),而在实践考核中,LBL+PBL组学员成绩在优秀这一分层评定中,优于LBL组,差异具有统计学意义(P0.05)。结论:LBL和PBL教学方法结合应用于物理诊断教学中,符合物理诊断教学的特点,更容易被学生接受,对于知识的识记和应用更有好处,从而更利于培养高素质医学人才,值得在物理诊断教学中进一步推广。     

How fast is fast? Eco‐evolutionary dynamics and rates of change in populations and phenotypes

It is increasingly recognized that evolution may occur in ecological time. It is not clear, however, how fast evolution – or phenotypic change more generally – may be in comparison with the associated ecology, or whether systems with fast ecological dynamics generally have relatively fast rates of phenotypic change. We developed a new dataset on standardized rates of change in population size and phenotypic traits for a wide range of species and taxonomic groups. We show that rates of change in phenotypes are generally no more than 2/3, and on average about 1/4, the concurrent rates of change in population size. There was no relationship between rates of population change and rates of phenotypic change across systems. We also found that the variance of both phenotypic and ecological rates increased with the mean across studies following a power law with an exponent of two, while temporal variation in phenotypic rates was lower than in ecological rates. Our results are consistent with the view that ecology and evolution may occur at similar time scales, but clarify that only rarely do populations change as fast in traits as they do in abundance.     

Frequency‐dependent selection for rare genotypes promotes genetic diversity of a tropical palm

Negative frequency‐dependent selection among species is a key driver of community diversity in natural systems, but the degree to which negative frequency‐dependent selection shapes patterns of survival and genetic diversity within species is poorly understood. In a 5‐year field experiment, we show that seedlings of a tropical palm with rare genotypes had a pronounced survival advantage over seedlings with common genotypes, with effect sizes comparable to that of light availability. This ‘rare genotype advantage’ led to an increase in population‐wide genetic diversity among seedlings compared to null expectations, as predicted by negative frequency‐dependent selection, and increased reproductive success in adult trees with rare genotypes. These results suggest that within‐species negative frequency‐dependent selection of genotypes can shape genetic variation on ecologically relevant timescales in natural systems and may be a key, overlooked source of non‐random mortality for tropical plants.     

Progress and prospects for the discovery of biomarkers for gastric cancer: a focus on proteomics

Introduction: Patient outcomes from gastric cancer vary due to the complexity of stomach carcinogenesis. Recent research using proteomic technologies has targeted components of all of these systems in order to develop biomarkers to aid the early diagnosis of gastric cancer and to assist in prognostic stratification.

Areas covered: This review is comprised of evidence obtained from literature searches from PubMed. It covers the evidence of diagnostic, prognostic, and predictive biomarkers for gastric cancer using proteomic technologies, and provides up-to-date references.

Expert commentary: The proteomic technologies have not only enabled the screening of a large number of samples, but also enabled the identification of diagnostic, prognostic and predictive biomarkers for gastric cancer. While major challenges still remain, to date, proteomic studies in gastric cancer have provided a wealth of information in revealing proteome alterations associated with the disease.     

脓毒症诊断的生物学标志物的研究进展

脓毒症是由致病微生物感染引发的全身炎症反应综合征(SIRS),合并血压降低且经快速液体复苏后血压仍不能恢复正常者称为脓毒性休克(Septic shock),其中一部分患者发展为多器官功能障碍综合症(MODS)。由于目前临床上仍缺乏早期敏感性诊断手段,脓毒症病死率居高不下。每10万人口中约50-300人会发生严重脓毒症,其短期死亡率达20%-25%,当发展为脓毒性休克时其死亡率达50%。随着分子生物学和现代生物技术的不断发展,人们发现多种生物标志物在脓毒症的早期诊断、病情及预后判断,疗效评估中发挥重要作用。因此深入了解脓毒症病理生理机制中不同生物标志物的意义及价值,对于脓毒症及其并发症的早期识别及干预,降低患者病死率及改善患者生活质量有积极意义。本文综述了近几年来对脓毒症的诊断和预后有一定价值的主要标志物及其应用。     

小蓬NeMT2基因的克隆及其植物表达载体的构建

该研究利用RACE ( Rapid amplification of cDNA ends)技术从小蓬中成功分离编码金属硫蛋白( Metal-lothionein,MT)的cDNA序列,命名为NeMT2,在GenBank中登录号为KT835290。该基因全长590 bp,开放阅读框为237 bp,编码78个氨基酸,编码的氨基酸序列中含有14个半胱氨酸残基( Cys,C),呈C-C,C-X-C,C-X-X-C排列,集中分布在肽链的N端和C端,基因编码蛋白的分子量为7.6036 kD,等电点为4.71。系统发育分析表明,小蓬金属硫蛋白NeMT2与藜科的海蓬子( AEF01492)和盐穗木( AHI62953)同源性最高,其次是甜菜( XP 010667708.1)。生物信息学分析表明,金属硫蛋白NeMT2无信号肽结构,属于非跨膜亲水性蛋白;疏水性分析表明,NeMT2蛋白的35~45个氨基酸之间有较强的疏水性,其中第41位Asp具最强的疏水性(1.444);结构预测分析该蛋白质二级结构的主要元件是无规则卷曲。通过RT-PCR对NeMT2基因的表达分析发现, NeMT2基因在铜矿区和非铜矿区的小蓬叶片中均有表达,但该基因在铜矿区小蓬叶片的表达量明显高于非铜矿区。将小蓬NeMT2基因定向克隆到植物表达载体pCAMBIA1300的35S 启动子下游,构建该基因的植物超表达载体pCAMBIA1300＋NeMT2。该研究结果为进一步研究该基因的功能和小蓬响应重金属胁迫的分子机制提供了一定基础。     

诺如病毒的致病机制及诊断

诺如病毒(Norovirus, NoV)是引起全人群急性胃肠炎暴发和流行的主要病原体,也是引起食源性疾病的最常见非细菌性病原体。由于缺少有效的小型动物及培养细胞研究模型,目前对NoV感染的致病机制尚不清楚。NoV实验室诊断技术发展成熟,尤其是近年来新技术的应用将进一步推动其诊断水平的提高,满足公共卫生和临床诊疗的新需求。     

16层螺旋CT三维重建与DR平片检查对外伤性肋骨骨折的诊断价值比较研究

目的:研究16层螺旋电子计算机断层扫描(CT)三维重建与数字化摄影(DR)平片检查对外伤性肋骨骨折的诊断价值,为临床诊治提供参考。方法:将2017年6月至2018年6月期间于本院接受诊治的82例外伤性肋骨骨折患者作为研究对象,所有患者均接受16层螺旋CT三维重建与DR平片检查,观察并记录患者的骨折发生部位,并比较两种诊断方法对外伤性肋骨骨折诊断的准确率、灵敏度、特异性、阳性预测值、阴性预测值以及漏诊情况。结果:82例外伤性肋骨骨折患者经影像学与临床诊断明确发生骨折179处,多发性骨折发生率为62.20%,单发性骨折发生率为37.80%,骨折肋骨段位中4-10段骨折发生率最高为69.83%,骨折肋骨水平阶段中腋肋骨折发生率最高为59.78%。相较于DR平片,16层螺旋CT三维重建诊断外伤性肋骨骨折的准确率、灵敏度、特异性、阳性预测值、阴性预测值更高,漏诊率更低,差异有统计学意义(P0.05)。结论:相较于DR平片检查,应用16层螺旋CT三维重建检查外伤性肋骨骨折能明显提高临床诊断的准确率、灵敏度和特异性,减少漏诊,可为临床诊治提供更可靠的信息,值得临床推广。