定量组织速度成像技术评价阿霉素诱导兔心肌病模型：与常规经胸超声心动图比较

目的:采用定量组织速度成像技术评价阿霉素诱导兔心肌病模型,并与常规经胸超声心动图比较其评估优势。方法:实验于2005-06/2006-08在大连医科大学完成。①实验分组及处理:取纯种新西兰白兔22只,雌雄不限,随机分成阿霉素组12只,给予阿霉素每次2mg/kg,以1g/L耳缘静脉注射,每周1次,注射8周;对照组10只每周注射2mL/kg生理盐水,共8周。②实验评估:每周应用HPSonos5500型彩色多普勒超声诊断仪(美国Agilent公司生产)对两组兔心脏进行左室收缩末期和舒张末期内径明、室间隔厚度、E峰、射血分数、左室短轴缩短率等常规超声参数测量,使用GEVivid7型彩色多普勒超声诊断仪(美国GE公司生产)进行收缩期和舒张期峰值速度、收缩期加速度定量组织速度成像参数测定。结果:22只兔进入统计。①对照组1～12周各参数与阿霉素组基础状态下比较无明显差异(P>0.05)。②第4周阿霉素组二尖瓣环运动的平均收缩期和舒张期峰值速度、收缩期加速度较基础状态明显减低(P均<0.05)。③第7周阿霉素组二尖瓣环运动的收缩期和舒张期峰值速度、收缩期加速度较基础状态明显减低(P<0.01),E峰较基础状态明显减低(P<0.05)。④第8周阿霉素组二尖瓣环运动的收缩期和舒张期峰值速度、收缩期加速度较基础状态明显减低(P<0.01),E峰较基础状态明显减低(P<0.01),左室收缩末期和舒张末期内径明显增大(P<0.05)。⑤第12周阿霉素组二尖瓣环运动的收缩期和舒张期峰值速度、收缩期加速度较基础状态明显减低(P<0.01),左室收缩末期和舒张末期内径明显增大(P<0.01),室间隔厚度、左室后壁厚度明显变薄(P<0.05),射血分数、左室短轴缩短率和E峰明显减低(P<0.01)。结论:定量组织速度成像参数可有效评价阿霉素诱导心肌病模型兔心肌的病理变化,较常规超声参数更敏感。     

两种荧光显微成像系统亚细胞定位的对比

目的:应用高分辨率荧光显微成像系统采集细胞器探针图像,并与激光共聚焦显微成像系统进行对比。方法:实验于2003-05/2004-01在解放军总医院完成。①实验材料:鼠肺毛细血管内皮细胞株(1H11)由上海复旦张江生物公司提供;荧光探针Rhodamine-123,Lucifer Yellow,DiOC6[3],BODIPY(美国Sigma公司)。②细胞培养及荧光探针染色:细胞培养采用含体积分数为0.2胎牛血清的低糖DMEM培养基,密度5×107L-1。选择Rhodamine-123作为细胞线粒体特异性荧光探针,选择DiOC6[3]作为细胞内质网特异性荧光探针,选择BODIPY作为细胞高尔基体特异性荧光探针,选择Lucifer Yellow作为细胞溶酶体探针。前3个探针在完全避光条件下与培养的细胞共同孵育0.5h,后者则共同孵育15h。③高分辨率荧光成像系统的图像采集:线粒体荧光图像采集,选取经Rhodamine-123共孵育完成的细胞,选择激发滤色镜为BP460-490,吸收滤色镜为BA515,分光镜为DM500,另加一绿通道液晶滤光片,激发出Rhodamine-123的荧光。电荷耦合器件采集图像并送入计算机。重复上述步骤,采用DiOC6[3]标记内质网,BODIPY标记高尔基体,Lucifer Yellow标记细胞溶酶体,激发条件同Rhodamine-123。分别采集同一视野靶细胞DiOC6[3]、BODIPY或Lucifer Yellow的荧光图像,完成全部图像采集并储存在计算机中。④激光共聚焦显微成像系统的图像采集:选择经4种探针染色的靶细胞,使用氩离子激光器在488nm激发Rhodamine-123,Rhodamine-123荧光通过配置有530/60-G发射滤光片的通道1探测。重复上述步骤,在488nm激发DiOC6[3]和BODIPY,在457nm激发Lucifer yellow,3种荧光均由通道1探测,后2个探针的发射滤光片的配置为515/30-G,DiOC6[3]选择530/60-G。由光电倍增管接收信号并传输入计算机成像。结果:①高分辨率荧光成像系统所采集图像,靶细胞中由荧光探针Rhodamine-123染色的线粒体呈多个典型的小棒状或卵圆状,聚集在核周;Lucifer yellow染色的溶酶体呈多个非对称球型,在胞浆内随机分布,颗粒尺寸通常大于线粒体;荧光探针DiOC6[3]着色的内质网占据胞浆的很大空间,以囊状聚集为特征;BODIPY特异性地结合在高尔基体上,荧光图像显示围绕在细胞核周围呈条索状。②与高分辨率荧光成像系统比较,激光共聚焦显微成像系统所采集的图像其荧光强度基本相同,但分辨率低、细节显示模糊、胞浆中细胞器的准确分布信息和形态特征显示效果欠佳。结论:两种荧光显微成像系统均可采集到细胞器探针的荧光图像。但高分辨率荧光成像系统采集的荧光图像具有细节清晰、分辨度高、准确显示胞浆中细胞器的分布信息和形态特征等优点。     

A Cost-Effectiveness Analysis of a Randomized Control Trial of a Tailored,Multifactorial Program to Prevent Falls Among the Community-Dwelling Elderly

Objective

To perform a cost-effectiveness analysis of a multifactorial, tailored intervention to reduce falls among a heterogeneous group of high-risk elderly people.

Cardiometabolic risk in impaired fasting glucose and impaired glucose tolerance: the Atherosclerosis Risk in Communities Study

OBJECTIVE: We compared and contrasted cardiovascular disease (CVD) risk factors, subclinical manifestations of CVD, incident coronary heart disease (CHD), and all-cause mortality by categories of impaired glucose regulation in nondiabetic individuals. RESEARCH DESIGN AND METHODS: The study included 6,888 participants aged 52-75 years who had no history of diabetes or CVD. All-cause mortality and incident CHD were ascertained over a median of 6.3 years of follow-up. RESULTS: Agreement between fasting and postchallenge glucose impairment was poor: 3,048 subjects (44%) had neither impaired fasting glucose (IFG) nor impaired glucose tolerance (IGT), 1,690 (25%) had isolated IFG, 1,000 (14%) had isolated IGT, and 1,149 (17%) had both IFG and IGT. After adjustment for age, sex, race, and center, subjects with isolated IFG were more likely to smoke, consume alcohol, and had higher mean BMI, waist circumference, LDL cholesterol, and fasting insulin and lower HDL cholesterol than those with isolated IGT, while subjects with isolated IGT had higher mean triglycerides, systolic blood pressure, and white cell counts. Measures of subclinical CVD and rates of all-cause mortality and incident CHD were similar in isolated IFG and isolated IGT. CONCLUSIONS: Neither isolated IFG nor isolated IGT was associated with a more adverse CVD risk profile.     

Balancing bias, reliability, noise properties and the need for parametric maps in quantitative ligand PET: [(11)C]diprenorphine test-retest data

[(11)C]diprenorphine (DPN) is a non-subtype selective opioid receptor PET ligand with slow kinetics and no region devoid of specific binding. Parametric maps are desirable but have to overcome high noise at the voxel level. We obtained parameter values, parametric map image quality, test-retest reproducibility and reliability (using intraclass correlation coefficients (ICCs)) for conventional spectral analysis and a derived method (rank shaping), compared them with values obtained through sampling of volumes of interest (VOIs) on the dynamic data sets and tested whether smaller amounts of radioactivity injected maintained reliability. Ten subjects were injected twice with either approximately 185 MBq or approximately 135 MBq of [(11)C]DPN, followed by dynamic PET for 90 min. Data were movement corrected with a frame-to-frame co-registration method. Arterial plasma input functions corrected for radiolabelled metabolites were created. There was no overall effect of movement correction except for one subject with substantial movement whose test-retest differences decreased by approximately 50%. Actual parametric values depended heavily on the cutoff for slow frequencies (between 0.0008 s(-1) and 0.00063 s(-1)). Image quality was satisfactory for restricted base ranges when using conventional spectral analysis. The rank shaping method allowed maximising of this range but had similar bias. VOI-based methods had the widest dynamic range between regions. Average percentage test-retest differences were smallest for the parametric maps with restricted base ranges; similarly ICCs were highest for these (up to 0.86) but unacceptably low for VOI-derived VD estimates at the low doses of injected radioactivity (0.24/0.04). Our data can inform the choice of methodology for a given biological problem.     

Dimensionality and construct validity of the Fugl-Meyer Assessment of the upper extremity

OBJECTIVE: To investigate the dimensionality and construct validity of the Fugl-Meyer Assessment of the upper extremity by using Rasch analysis. DESIGN: Secondary analysis of pooled data from 2 existing datasets: a randomized therapeutic exercise clinical trial and a cohort longitudinal study of stroke recovery. SETTING: University research center. PARTICIPANTS: A total of 512 subjects, ages 69.8+/-11.1 years, who were 0 to 145 days poststroke. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: Dimensionality was examined with principal components analysis and Rasch item-fit statistics. The Rasch-derived item hierarchy was examined for consistency with the expected course of poststroke upper-extremity recovery suggested by the reflex-hierarchical conceptual model underlying the assessment. RESULTS: Factor loadings and item infit statistics suggested that the 3 reflex items were empirically disconnected from other assessment items. The reflex items were removed. The modified 30-item assessment showed a unidimensional structure. The Rasch-item-difficulty order was not consistent with the expected item order. CONCLUSIONS: The items testing resting-state reflexes may threaten the assessment's dimensionality. With reflex items removed, the assessment is a unidimensional measure of volitional movement. The Rasch-generated item-difficulty order challenges the hierarchical structure implied by the instrument's underlying conceptual framework.     

Flash microwave-assisted solvothermal (FMS) synthesis of photoactive anatase sub-microspheres with hierarchical porosity

The synthesis of nanostructured sub-microspheres of TiO₂ anatase with hierarchical nano- and mesoporosity was successfully achieved by using an innovative approach that applies the principles of acidic digestion to microwave (MW) solvothermal synthesis. This process, termed flash microwave-assisted solvothermal (FMS) synthesis, facilitates the formation of spherical particles without surfactants or templating agents, exploiting the rapid reaction kinetics engendered by MW heating. Unlike many other MW-assisted solvothermal methods, the application of constant MW power leads to a rapid increase of the autogenous pressure, inducing burst-nucleation of small primary crystallites and subsequent rapid agglomeration into secondary particles, with reaction times reduced to minute-timescales. The use of non-aqueous polar solvents such as ethanol is key to the production of regular spheres with a narrow size distribution, composed of nanocrystallites. Morphology, porosity, specific surface area, phase composition, crystallite size and optical properties of the particles can be controlled via a judicious selection of physical and chemical synthesis parameters, especially precursor choice and acid concentration. The complex structure of the particles leads to surface areas of up to ca. 500 m² g⁻¹ with intergranular mesoporosity. The as-synthesised FMS particles show increased adsorption under dark conditions and selective de-ethylation of rhodamine B under visible light compared to a commercial photocatalyst (Degussa P25). The photodegradation mechanism hinges on the capacity of the spheres to accept electrons from the photoexcited state of molecules at the particle surface, with the large sphere surface area maximising adsorption capacity and improving the efficiency of the photocatalytic processes. The singular characteristics and properties of the particles could pave the way for further applications in water purification and optoelectronic devices.

Photoactive nanostructured TiO₂ sub-microspheres can be fabricated by “microwave flash synthesis” in minute timescales.