Estimated GFR for Living Kidney Donor Evaluation

All living kidney donor candidates undergo evaluation of GFR. Guidelines recommend measured GFR (mGFR), using either an endogenous filtration marker or creatinine clearance, rather than estimated GFR (eGFR), but measurement methods are difficult, time consuming and costly. We investigated whether GFR estimated from serum creatinine (eGFRcr) with or without sequential cystatin C is sufficiently accurate to identify donor candidates with high probability that mGFR is above or below thresholds for clinical decision making. We combined the pretest probability for mGFR thresholds <60, <70, ≥80, and ≥90 mL/min per 1.73 m² based on demographic characteristics (from the National Health and Nutrition Examination Survey) with test performance of eGFR (categorical likelihood ratios from the Chronic Kidney Disease Epidemiology Collaboration) to compute posttest probabilities. Using data from the Scientific Registry of Transplant Recipients, 53% of recent living donors had predonation eGFRcr high enough to ensure ≥95% probability that predonation mGFR was ≥90 mL/min per 1.73 m², suggesting that mGFR may not be necessary in a large proportion of donor candidates. We developed a Web‐based application to compute the probability, based on eGFR, that mGFR for a donor candidate is above or below a range of thresholds useful in living donor evaluation and selection.     

Distinguishing characteristics of stem cells derived from different anatomical regions of human degenerated intervertebral discs

Introduction

Several types of stem cells have been successfully demonstrated to exist in the human degenerated intervertebral disc (IVD), which is composed of annulus fibrosus (AF), nucleus pulposus (NP) and cartilage endplate (CEP). However, the differences in the biological characteristics among these and bone marrow derived mesenchymal stem cells (BM-MSCs) remain unclear.

Materials and methods

To investigate this issue, cells were harvested from human AF, NP, CEP, and bone marrow, respectively; passage 2 cells were selected using the agarose suspension culture system to obtain stem cell clones. Following expansion in vitro, stem cells from different anatomical regions were compared regarding the morphology, proliferation ability, immunophenotypic expression, and multi-lineage differentiation capacity. In addition, stem cell-alginate bead compositions were constructed for the comparison of DNA and sGAG content.

Results

There were subtle differences regarding cell morphology, but no significant differences in proliferation ability among the four types of stem cells. For the immunophenotypic analysis, all stem cells basically fulfilled the criteria for mesenchymal stem cells (MSCs), which have been published by the International Society for Cellular Therapy (ISCT), with a significant difference in CD105 expression. A comparison of the osteogenic capacities indicated: cartilage endplate-derived stem cells (CESCs) > annulus fibrosus-derived stem cells (AFSCs) > BM-MSCs > nucleus pulposus-derived stem cells (NPSCs). The chondrogenesis difference was similar to osteogenesis. For adipogenesis: BM-MSCs >NPSCs >CESCs >AFSCs. In the stem cell/alginate composition, the CESCs consistently showed the superior chondrogenic potential among all those cell types.

Conclusions

Our data indicated that all the four types of stem cells shared some similar biological properties (regarding shape, proliferation ability and immunophenotypic expression). CESCs, which had the strongest osteogenic and chondrogenic potentials, may serve as excellent seed cells for NP/cartilage or bone tissue engineering.

     

基于Cog Tool的数字界面交互行为认知模型仿真研究

目的确定人在视觉信息搜索中的通用认知模式,归纳符合用户认知模式的基本设计准则。方法在用户需求一致性的前提下,通过Cog Tool可视化仿真模型将用户交互过程中的每一步骤进行拆解分析,找出用户在面对不同界面引导作用下的内在认知规律,并探讨界面布局的不同对用户搜索用时的影响,同时结合眼动实验,对比用户在实际操作过程中与模拟操作情况下的认知差异。结果通过Cog Tool的仿真分析与眼动实验相结合的实验数值对比,将用户在交互过程中的内在认知规律提取出来。结论本研究提出的面向界面布局的设计准则,可帮助设计师提高信息认知效率。     

注射钆剂后弥散加权成像对乳腺肿瘤诊断的影响

目的：评估1.5 T MRI中乳腺肿瘤患者使用钆对比剂是否对弥散加权成像（DWI）有显著性影响。方法行乳腺MRI检查的女性患者40例（共计44个病灶）,分别测量增强前后DWI图像信噪比（SNR）和对比噪声比（CNR）、病灶增强前后的表观扩散系数（ADC）及指数表观扩散系数（eADC）。结果给药前后DWI图像的SNR及CNR差异无统计学意义。乳腺癌给药前后的ADC值（t=-4.023, P=0.001）及eADC值（t=4.082, P=0.001）差异有统计学意义,良性肿瘤给药前后的ADC值（t=-1.700, P=0.103）及eADC值（t=1.341, P=0.194）差异无统计学意义。结论增强后行DWI是可行的,并且有助于提高其鉴别乳腺良恶性肿瘤的能力。     

便携式实时肌疲劳分析系统研制

目的针对运动科学领域的需求,开发一套便携式肌疲劳实时分析系统。方法系统由信号采集端、FPGA信号处理端和结果显示存储端组成。信号采集端由六通道肌电传感器通过Ag-Ag Cl电极采集人体表面肌电信号,经过1 K采样率ADC转化,由C8051F410控制蓝牙2.0模块发送信号到FPGA信号处理端。FPGA信号处理端接收s EMG信号、解析数据、提取活动段、并计算与肌疲劳分析相关的时频域参数。结果显示存储端通过S3C6410控制LCD显示以及SD卡存储。结果系统实现了六通道s EMG的实时采集以及肌疲劳参数的实时计算、显示和存储。对16位受试者的踢腿运动肌疲劳分析验证了系统的有效性。结论研制的肌疲劳实时分析系统具有强大的实时肌疲劳分析功能,同时具有便于携带、使用方便、可扩展等特点,适用于日常运动疲劳监测。     

圆柱型Halbach永磁魔环研究进展

受局部饱和和局部退磁效应的影响以及磁材料性能的限制,永磁体的气隙磁场一般难以达到4T。Halbach永磁魔环结构磁材料利用效率高,且能够产生比剩磁更高的静磁场,因而近年来在磁共振成像领域得到了广泛关注。本文针对Halbach永磁魔环的构成形式,介绍了永磁魔环、阵列永磁魔环、永磁双魔环和单边永磁魔环的研究现状,分析了这些魔环结构由于永磁磁块形状、尺寸,永磁材料受温度变化影响,和加工工艺等因素引起的磁场均匀性较差等主要问题,并对圆柱型Halbach永磁魔环在NMR、MRI和便携式分析仪器等方面的应用进行了展望。     

Y染色体AZFc部分缺失和全缺失对精子发生的影响

目的 研究Y染色体AZFc部分缺失(gr/gr缺失、b2/b3缺失)和AZFc全缺失(b2/b4缺失)对精子发生的影响.方法 实验组选择非梗阻性无精子症者458例,对照组选择符合卫生部标准的汉族合格捐精者301例.所有受试者均抽取外周血,抽提DNA,选择Y染色体序列标签位点(STS),经多重PCR技术检测Y染色体AZFc部分缺失与全缺失,对结果进行统计学分析.结果 实验组AZFc部分缺失为:gr/gr缺失41例(8.9%),b2/b3缺失11例(2.4%):AZFc全缺失5例(1.1%).对照组AZFc部分缺失:gr/gr缺失23(8.6%)例, b2/b3缺失7例(2.3%):未发现AZFc全缺失.两组比较,AZFc全缺失差异显著(P＜0.05);AZFc部分缺失(gr/gr缺失、b2/b3缺失)发生率无显著性差异(P＞0.05).结论 汉族男性Y染色体AZFc部分缺失(gr/gr、b2/b3缺失)在非梗阻性无精子症患者和IE常捐精者中都存在,但无统计学意义,不能作为精子发生障碍的危险因子.AZFc全缺失(b2/b4缺失)则引起严重的生精功能障碍,可作为精子发生障碍的危险因子之一.     

Outcomes of patients with clinical CIS-only disease treated with radical cystectomy

Objectives  To report the long-term oncological efficacy of radical cystectomy for patients with presumed clinical CIS only disease, to characterize the likelihood of clinical understaging, and to characterize the pattern of recurrence. Methods  One thousand six hundred patients have undergone radical cystectomy and pelvic lymph node dissection with intent to cure from August 1971 to December 2005 at the University of Southern California; 27 patients from this cohort who satisfied both the inclusion and exclusion criteria were identified. Relevant clinical and pathological data at time of cystectomy and during follow-up were reported. Overall and recurrence-free survival was estimated using the Kaplan–Meier method. Results  At time of cystectomy, 33% of patients were found to be clinically understaged. Median follow-up was 94 months. Estimated 5- and 10-year overall survival was 87 and 56%, respectively. Estimated 5- and 10-year recurrence-free survival was 100 and 83%, respectively. Conclusions  Excellent long-term survival outcomes can be achieved with radical cystectomy. Radical cystectomy should be strongly considered for patients who have failed prior intravesical therapy. Long-term surveillance of the retained urethra and of the upper tract is essential, as recurrence can occur years following cystectomy. Patients who recur are at high risk of dying from disease.