Comparisons of false negative rates from a trend test alone and from a trend test jointly with a control-high groups pairwise test in the determination of the carcinogenicity of new drugs

Interest has been expressed in using a joint test procedure that requires that the results of both a trend test and a pairwise comparison test between the control and the high groups be statistically significant simultaneously at the levels of significance recommended in the FDA 2001 draft guidance for industry document for the separate tests in order for the drug effect on the development of an individual tumor type to be considered as statistically significant. Results of our simulation studies show that there is a serious consequence of large inflations of the false negative rate through large decreases of false positive rate in the use of the above joint test procedure in the final interpretation of the carcinogenicity potential of a new drug if the levels of significance recommended for separate tests are used. The inflation can be as high as 204.5% of the false negative rate when the trend test alone is required to test if the effect is statistically significant. To correct the problem, new sets of levels of significance have also been developed for those who want to use the joint test in reviews of carcinogenicity studies.     

Giant Coronary Artery Aneurysms: Review and Update

Giant coronary artery aneurysms are rare, with a reported prevalence of 0.02% to 0.2%. Causative factors include atherosclerosis, Takayasu arteritis, congenital disorders, Kawasaki disease, and percutaneous coronary intervention. Most giant coronary artery aneurysms are asymptomatic, but some patients present with angina pectoris, sudden death, fistula formation, pericardial tamponade, compression of surrounding structures, or congestive heart failure. Clinical sequelae include thrombus formation, embolization, fistula formation, and rupture. Surgical correction is generally accepted as the preferred treatment for giant coronary artery aneurysms. We present an illustrative case of a giant 70 × 40-mm coronary artery aneurysm in a 56-year-old man who declined surgery and died one month later. In addition, we provide a review of the medical literature on giant coronary artery aneurysms.     

pFDR and pFNR estimation for brain networks construction

Recent developments in the study of brain functional connectivity are widely based on graph theory. In the current analysis of brain networks, there is no unique way to derive the adjacency matrix, which is a useful representation for a graph. Its entries, containing information about the existence of links, are identified by thresholding the correlation between the time series that characterized the dynamic behavior of the nodes. In this work, we put forward a strategy to choose a suitable threshold on the correlation matrix considering the problem of multiple comparisons in order to control the error rates. In this context we propose to control the positive false discovery rate (pFDR) and a similar measure involving false negatives, called the positive false nondiscovery rate (pFNR). In particular, we provide point and interval estimators for pFNR and a method for balancing the two types of error, demonstrating it by using functional magnetic resonance imaging data and Monte Carlo simulations. Copyright © 2013 John Wiley & Sons, Ltd.     

Is the Dissociative Adult Suggestible? A Test of the Trauma and Fantasy Models of Dissociation

Psychologists have long assumed a connection between traumatic experience and psychological dissociation. This hypothesis is referred to as the trauma model of dissociation. In the past decade, a series of papers have been published that question this traditional causal link, proposing an alternative fantasy model of dissociation. In the present research, the relationship among dissociation, suggestibility, and fantasy proneness was examined. Suggestibility was measured through the Gudjonsson Scale of Interrogative Suggestibility (GSS) as well as an autobiographically based version of this measure based on the events of September 11, 2001. Consistent with prior research and with the trauma model, dissociation correlated positively with trauma severity (r = .32, p < .01) and fantasy proneness (r = .60, p < .01). Inconsistent with the fantasy model, dissociation did not correlate with the neutral form of the GSS and correlated negatively (r = –.24, p < .05) with the trauma-focused form of this suggestibility measure. Although some participants did become quite emotional during the procedure, the risk/benefit ratio was perceived by almost all participants to be positive, with more reactive individuals evaluating the procedure more positively. The results consistently support the trauma model of dissociation and fail to support the fantasy model of dissociation.     

新型冠状病毒肺炎核酸检测中的假阴性分析及对策

新型冠状病毒肺炎(COVID-19)的疫情引发了全世界的关注。早期诊断对COVID-19的治疗、患者预后尤为关键。临床检验中发现早期的COVID-19患者核酸检测多次呈假阴性,特别是不同时间多次阴性结果后转为阳性,给临床诊断和疾病控制带来极大困扰。该文立足于疫情的早日防控,从临床、检验的不同视角,从标本采集、检测方法、产品稳定性等多方面剖析产生假阴性的可能原因,并且结合临床实践和检测技术,从整合特异性实验室指标,规范标本采集方式和过程,严格检测试剂的监管和审批等方面提出行之有效的方案,旨在为切实降低检测假阴性或假阳性率提供临床参考,为COVID-19临床准确诊断及疫情防控提供有力支撑。     

POTENTIAL FALSE-POSITIVE RESULTS WITH ANTIGEN ENHANCEMENT FOR IMMUNOHISTOCHEMISTRY OF THE p53 GENE PRODUCT IN COLORECTAL NEOPLASMS

Aberrant crypt foci (ACF) are putative precursor lesions of colon cancer, recently identified on the methylene blue-stained mucosal surface of human colon. No mutations in K- ras or p53 genes were found by non-radioactive single-strand conformation polymorphism analysis in 14 ACF collected from five patients. Using the more sensitive method of allele-specific polymerase chain reaction (PCR) for K- ras , 8 of 14 ACF were found to contain K- ras mutations, suggesting that mutated cells are present in minute clones in ACF. No dysplasia was observed in any of the ACF containing a mutated clone. The presence of K- ras mutations in ACF suggests that these lesions occur at a very early stage in human colorectal carcinogenesis.     

The Biology of Veganism: Plasma Metabolomics Analysis Reveals Distinct Profiles of Vegans and Non-Vegetarians in the Adventist Health Study-2 Cohort

It is unclear how vegetarian dietary patterns influence plasma metabolites involved in biological processes regulating chronic diseases. We sought to identify plasma metabolic profiles distinguishing vegans (avoiding meat, eggs, dairy) from non-vegetarians (consuming ≥28 g/day red meat) of the Adventist Health Study-2 cohort using global metabolomics profiling with ultra-performance liquid chromatography mass spectrometry (UPLC-MS/MS). Differences in abundance of metabolites or biochemical subclasses were analyzed using linear regression models, adjusting for surrogate and confounding variables, with cross-validation to simulate results from an independent sample. Random forest was used as a learning tool for classification, and principal component analysis was used to identify clusters of related metabolites. Differences in covariate-adjusted metabolite abundance were identified in over 60% of metabolites (586/930), after adjustment for false discovery. The vast majority of differentially abundant metabolites or metabolite subclasses showed lower abundance in vegans, including xanthine, histidine, branched fatty acids, acetylated peptides, ceramides, and long-chain acylcarnitines, among others. Many of these metabolite subclasses have roles in insulin dysregulation, cardiometabolic phenotypes, and inflammation. Analysis of metabolic profiles in vegans and non-vegetarians revealed vast differences in these two dietary groups, reflecting differences in consumption of animal and plant products. These metabolites serve as biomarkers of food intake, many with potential pathophysiological consequences for cardiometabolic diseases.     

老龄化对错误记忆影响的神经心理学研究

目的探讨老龄化对错误记忆的神经心理学影响,并对产生老年人错误记忆的神经心理学机制进行研究。方法将60名教育程度相匹配的受试者分为青年组人(44岁及以下)、中年组(45～59岁)、老年组(60岁及以上),每组20名;采用图片诱发的和词汇诱发的错误记忆的实验范式(DRM范式)进行研究。结果老年组图片诱发的错误记忆高于青年组、中年组,差异有统计学意义(P=0. 000,P=0. 000)。中年组词汇诱发的关键诱饵错误再认高于青年组、老年组,差异有统计学意义(P=0. 001,P=0. 000)。老年组词汇诱发的无关项目的错误再认高于中年组、青年组,中年组的高于青年组,这三组之间两两比较差异均有统计学意义(P=0. 032,P=0. 000,P=0. 005);且无关项目的错误再认和学习项目正确再认呈负相关(P=0. 000)。结论老龄化错误记忆的增加不仅与其本身记忆编码和提取功能减退有关,还可能与记忆监测的障碍有关。     

徐长卿及其一种伪品的鉴别

[目的]鉴别市场上流通的一种假冒徐长卿的伪品,避免误用.[方法]用传统鉴定方法及现代鉴定技术,对徐长卿与伪品徐长卿进行比较鉴别.[结果]徐长卿与伪品徐长卿的药材性状、显微特征及高效液相色谱法(HPLC)指纹图谱均存在不同之处.[结论]此伪品与正品徐长卿有明显差异,不能用于临床.     

基于多学科协作的内瘘专项小组护理模式在动静脉内瘘假性动脉瘤患者中的应用

目的:探讨基于多学科协作的内瘘专项小组护理模式在动静脉内瘘（AVF）假性动脉瘤患者中的应用效果。方法:采用便利抽样法,选取2019年2月—2020年8月在郑州市第七人民医院血液净化中心接受治疗的92例AVF假性动脉瘤患者为研究对象,按照随机数字表法分为对照组和观察组,每组各46例。对照组患者接受常规护理模式,观察组患者...