50岁以上正常人左室舒张期彩色多普勒血流频谱参数变化的研究

目的探讨５０岁以上正常人左室舒张期脉冲多普勒频谱的参数变化情况。方法选择一年半时间内受检的所有５０岁以上正常人４７５例，按每１０岁为一组分４组进行分析。受检者取左侧卧位，常规显示心尖四腔心切面，取样容积置于二尖瓣尖，使声束与二尖瓣血流方向夹角＜１５°，以连续三个心动周期的平均值分别测量Ｅ峰、Ａ峰、Ｅ／Ａ及Ｅ峰减速时间并统计。结果发现Ｅ峰高于正常值低限的例数、平均Ｅ峰血流速度以及Ｅ／Ａ均随着年龄的增加而下降，Ｅ峰减速时间则随着增龄而增加。结论左室舒张期血流频谱的所有参数与年龄有显著的相关性，明显随着增龄而变化，并且有其规律性。     

ROBUST GUARANTEED COST CONTROL OF UNCERTAIN NON-LINEAR ROBOTIC SYSTEM USING MIXED MINIMUM TIME AND QUADRATIC PERFORMANCE INDEX

To provide better transient performance in controlling robots, a mixed minimum time and quadratic performance index is used. For known and uncertain revolute robot manipulators a conventional optimal control and a robust guaranteed cost control are proposed respectively. Asymptotic stability is also discussed based on the Lyapunov direct method. The proposed robust control is continuous and requires no knowledge of the uncertain system except for bounding functions.     

彩色多普勒超声对感染性休克患者急性肾损伤的预测价值

背景 感染性休克患者存在肾脏血液灌注异常,严重时可诱发急性肾损伤(AKI),严重威胁患者生命安全;彩色多普勒超声(CDU)可用于评估肾脏血流变化,但有关其在感染性休克患者AKI评估中价值的研究较少。目的 通过CDU评价感染性休克患者AKI的发生情况及其血流动力学改变。方法 选取2019年6月至2021年7月徐州市中心医院收治的105例确诊为感染性休克的患者并纳入感染组,选取同期健康体检者58例并纳入对照组,收集受试者一般资料。采用CDU检查受试者肾脏血流动力学指标[肾动脉管腔内径(D)、收缩期血流峰值速度(Vs)、舒张末期血流速度(Vd)、阻力指数(RI)、搏动指数(PI)],比较感染组与对照组的一般资料及肾脏血流动力学指标。根据感染组患者入院72 h内发生AKI与否将其分为AKI组及非AKI组,比较AKI组与非AKI组肾脏血流动力学指标。应用受试者工作特征(ROC)曲线分析肾脏血流动力学指标对感染性休克患者发生AKI的预测价值。应用单因素分析及多因素Logistic回归分析探讨感染性休克患者发生AKI的影响因素。以AKI由轻到重的程度将患者分为AKIⅠ组、AKIⅡ组、AKIⅢ组,比较...     

踝肱指数和肱踝动脉脉搏波速度与血管舒张功能联合载脂蛋白B与载脂蛋白A-1比值对中青年冠心病血瘀证的预测价值研究

背景 冠心病属中医“胸痹心痛”范畴,其证候分布以血瘀证最为多见,与老年人相比,中青年血瘀证的发生率更高。本研究在团队前期研究基础上进行拓展,首次运用动脉弹性和血管内皮功能检测联合载脂蛋白比值诊断中青年冠心病血瘀证,旨在为早期发现中青年冠心病血瘀证提供新思路,也可为优化补充冠心病血瘀证的诊断标准提供参考。目的 探讨踝肱指数(ABI)、肱踝动脉脉搏波速度(baPWV)、血管舒张功能(FMD)联合载脂蛋白B与载脂蛋白A-1比值(apoB/apoA-1)与中青年冠心病血瘀证的关系及其预测价值。方法 选取2016年12月至2021年12月于中日友好医院中西医结合心脏内科住院治疗的中青年(<50岁)冠心病患者,并根据《冠心病血瘀证诊断标准》分为血瘀证组和非血瘀证组。收集患者首次冠状动脉造影前的ABI、baPWV、FMD和apoB/apoA-1等临床资料。采用多因素Logistic回归分析构建中青年冠心病患者血瘀证的预测模型,并采用受试者工作特征(ROC)曲线进行预测价值评价。结果 本研究共纳入中青年冠心病患者206例,其中血瘀证组127例,非血瘀证组79例。多因素Logistic回归分析结果...     

基于FT-CMR的心脏功能评估参数对心房颤动冷冻球囊消融患者治疗后复发的预测效能分析

目的 探讨分析基于心脏磁共振特征追踪技术(FT-CMR)的心脏功能评估参数对心房颤动冷冻球囊消融患者治疗后复发的预测效能。方法 选取2019年6月至2020年12月收治的126例预行冷冻球囊消融术的心房颤动患者为研究对象,术前均进行心脏磁共振检查,根据术后6个月内患者有无复发将其分为窦性心律组72例和房颤复发组54例。比较两组患者左心房应变及应变率参数,采用FT-CMR评估患者心脏功能,并进行单因素、多因素logistic回归分析,探讨FT-CMR心脏功能评估参数对心房颤动冷冻球囊消融术后复发的预测价值。结果 房颤复发组患者女性、高血压、糖尿病、非阵发性心房颤动比例显著高于窦性心律组(P<0.05)。房颤复发组患者左心房总应变(Es)、左心房正向应变率峰值(SRs)、左心房被动应变(Ee)、心室舒张早期负向应变率峰值(SRe)、左心房整体纵向应变(PLAS)参数值低于窦性心律组(P<0.05)。Logistic多因素回归分析结果显示,性别(OR=3.511,95%CI:1.036～11.906)、PLAS(OR=1.089,95%CI:1.039～1.141)是心房颤动冷冻...     

Renewal of the membrane complex of Schistosoma mansoni is closely associated with lipid metabolism

Metabolic pathways leading to lipid biosynthesis in four different developmental stages of Schistosoma mansoni were explored and quantified by incubation in the presence of labeled precursors in a chemically defined medium. At the schistosomulum stage and in male, female, or paired worms, glycerol and oleate incorporation into neutral lipids, mainly in the form of triacylglycerols, was greater than into phospholipids, whereas in 11-and 15-day-old worms, synthesis mainly led to phospholipids. Incorporation into phospholipids was recovered largely in phosphatidylcholine, and distribution into other phospholipids depended on the developmental stage. Incorporation of choline and ethanolamine into their respective phospholipids represented up to 15% of the parasitic phospholipid content. The formation of phosphatidylcholine by phosphatidylethanolamine methylation occurred mainly in the immature parasitic stages. Inositol incorporation was also measurable, whereas [14C]serine incorporation was low or undetectable. Addition of 1-palmitoyl-2-[14C]oleyl phosphatidylcholine revealed a very high uptake of this phospholipid by the immature stages but further metabolism was not detectable. In contrast, adult S. mansoni were completely unable to take up or absorb this exogenous phospholipid. The most striking aspect of this study was the relatively high metabolic activity in 11-day-old worms and the lower but sustained activity on day 15 and at the schistosomulum stage. By comparison, biosynthetic activity in adult S. mansoni, on which research studies have been focused until now, was very low. We also discuss the participation of lipid metabolism in the constant renewal of the membrane complex which is essential to parasitism by S. mansoni.     

Setting out the frame conditions for feasible use of FFPE derived RNA

Introduction

The usage of formalin-fixed paraffin embedded (FFPE) tissue is characterized by its long shelf-life and simple handling. Therefore it is the most commonly available tissue specimen in routine diagnostics and histological studies. Formaldehyde fixation may result in RNA degradation and cross linking with proteins, while storage conditions also affect RNA integrity. The present study was designed to investigate the influence of these factors on RNA analysis.

Immunochemical characterization of mouse brain-associated theta (Thy-1) antigen.

The Thy-1 antigens or rat brain and thymus have been isolated and chemically characterized, but those of mice have not been identified. Moreover, it is uncertain whether the antigens are glycolipids or glycoproteins. This study with highly purified preparations of gangliosides GM₁, ¹GD_1a, GD_1b and GT_1b from bovine brain and several ganglioside fractions from mouse brain showed that Thy-1 activity does not reside in gangliosides, but rather in the chloroform-methanol-insoluble residue of brain remaining after extraction of gangliosides. The antigen could be solubilized from this residue with a non-ionic detergent. The antigenic activity of the solubilized preparation was heat-labile but resistant to periodate. The chemical properties of the Thy-1 antigen of mouse brain are discussed.     

Predictive value of early HCV RNA quantitation for sustained response in nonresponders receiving daily interferon and ribavirin therapy

The prognostic value of early hepatitis C virus (HCV)-RNA load was evaluated among nonresponder patients to previous interferon (IFN) therapy treated with daily IFN and ribavirin. One hundred-six nonresponders (83 men), mean age 44.8 +/- 11 years, were treated with IFN-alpha 2b 3 MU/day for 24 weeks, followed by 3 MU x 3/week for 24 weeks plus ribavirin 1-1.2 g/day for 48 weeks. HCV RNA was quantified by Versant HCV RNA 3.0 assay (Bayer). The predictive values of the baseline and the change in viral load at week 1, 4, and 12 for sustained virological responses were analyzed using receiver operating characteristic (ROC) curves, as well as predictive values of >2 log(10) drop from baseline by weeks 1, 4, and 12 in combination with undetectable HCV RNA for sustained virological response. Thirty-two patients (30.2%) were sustained virological responders. The highest area under the curve was obtained at week 4. The unquantifiable HCV RNA level, in combination with at least a 2 log(10) drop in viral load by week 4 and week 12, had a negative predictive value of 96% and 97%, respectively. Nonresponse can be predicted as early as week 4 or week 12 in nonresponders treated with daily IFN and ribavirin.     

CO2 dissociation curves of oxygenated whole blood obtained at rest and in exercise

Summary In vitro CO₂ dissociation curves for oxygenated whole blood were determined in 19 healthy male subjects at rest and during submaximal and maximal bicycle work. Hemoglobin concentration and blood lactate increased with increasing work load and accordingly buffer value of the whole blood increased while bicarbonate and Base Excess (BE) decreased, resulting in a downward shift of the CO₂ dissociation curve during exercise. Despite the marked increase in buffer values of the blood, the slopes of the CO₂ dissociation curves during exercise were found to be about the same as those obtained at rest. It was inferred that the increasing effect of increased buffer value, on the dissociation slope, was essentially compensated by the decreasing effect of diminished bicarbonate content. The advantages of this relatively constant CO₂ dissociation slope for the indirect measurement of cardiac output by the Fick principle are discussed.