fMRI of the brainstem using dual-echo EPI

The brainstem is the part of the human brain that plays a pivotal role in the maintenance of many critical body functions. Due to the elevated level of cardiogenic noise, few fMRI studies have investigated the brainstem so far. Cardiac-gated echo-planar imaging with acquisition of two echoes per excitation (dual-echo EPI) is one method that significantly reduces cardiogenic noise and, thus, allows for fMRI measurements of the brainstem. As information on optimal preprocessing approaches for brainstem-fMRI data is still scarce, the goal of this study was to compare different combinations of normalization and smoothing procedures as implemented in standard fMRI software packages and to identify the combinations yielding optimal results for dual-echo EPI. 21 healthy subjects were measured while executing a simple motor paradigm to activate the facial and trigeminal motor nucleus in the brainstem. After motion correction and calculation of T(2)*-maps the data were preprocessed with 24 combinations of standard normalization (SPM classic, SPM unified, FSL, ABC) and smoothing procedures (pre-/post-smoothing with 3mm-, 4.5mm- and 6mm-kernel) before undergoing first- and second-level statistical analysis. Activation results were compared for first-level and second-level statistics using two anatomically defined regions of interest. Five methods were found to be sensitive for activation of both nuclei. These included FSL normalization with 3mm and 4.5mm pre-smoothing as well as 3mm post-smoothing, SPM unified normalization with 3mm pre-smoothing and ABC normalization with 4.5mm pre-smoothing. All these methods can be recommended for normalization and smoothing when analyzing fMRI data of the brainstem acquired by cardiac-gated dual-echo EPI.     

DNA microarrays: their use and misuse

DNA microarray represents one of the major advances in functional genomics. Its ability to study expression of several thousands of genes or even all genes in the entire genome in a single experiment has changed the way in which we address basic biomedical questions. Numerous publications have shown its utility in drug discovery, disease diagnosis, novel gene identification, and understanding complex biological systems. However, there are substantive technical issues associated with the use of this technology that limit the interpretation of microarray data. In this review, we first give an overview of DNA microarray technology and then focus on uncertainty areas of microarray technology that include making microarrays, isolation of RNA and labeling, hybridization and scanning, and data analysis. The center theme of this review is to improve microarray reproducibility by addressing common technical problems. Finally, we briefly summarize microarray's applications in biomedical research.     

广东省性病实验室规范化建设与质量管理体系研究

目的　探讨性病实验室规范化管理和质量管理体系。方法　根据各实验室的任务、人员和设备等条件,采用三级和中心实验室模式开展全省性病实验室规范化建设。通过室内质控和室间质评方式建立性病实验室质控体系。结果　确定规范化性病实验室的三级管理体制与各级任务。2 0 0 3年9月～2 0 0 4年9月,举办性病实验室诊断技术培训班8期,培训学员4 70人。5 9间完成规范化建设并申请达标的性病实验室中,38间性病实验室通过考评,包括三级性病实验室5间,二级1 9间和一级1 4间。研究建立了性病实验室室内质控和室间质评的质量管理体系。首批1 9间通过考评的实验室的室间质评结果均符合要求,3间得分>90分,评为优秀;1 2间得75～90分,评为良好;4间得6 0～75分,评为合格。结论　规范化性病实验室和质量管理体系的建立,确保性病实验室科学管理和发展,对于性病艾滋病的防治有重要的意义。     

尿液特征组分与糖尿病早期肾损害的关系初探

目的对尿液特征组分与糖尿病早期肾损害的关系进行了初步探索。方法对2011年12月-2012年5月间28例2型糖尿病组、33例2型糖尿病肾病组及26例健康对照组尿液中尿蛋白含量和几种常见非蛋白氮物质,包括肌酸、尿囊素、肌酐、尿酸和假尿嘧啶核苷的浓度进行测定,采用多种归一化方法对数据进行对比分析,并通过t检验减少高效液相色谱测定的变量信息,保留P〈O．05的检出峰进行主成分分析,获得分类结果。结果采用体积归一化方法,发现健康对照组尿液中肌酸、尿囊素和尿酸的含量与2型糖尿病组和糖尿病肾病组相比,差异均有统计学意义（P〈0．05）,2型糖尿病组尿液中尿蛋白的浓度与糖尿病肾病组相比,差异有统计学意义（P〈0．05）。结论通过肌酸、尿囊素、尿酸和尿蛋白的联合测定为肾脏损伤程度的监测及疗效观察提供依据,为2型糖尿病患者肾功能损坏的早期预防与诊断进行初步判断提供了新的方法。     

数字图书馆建设的标准化

通过对数字图书馆建设标准化重要性的论述,探讨数字图书馆建设中涉及的数字资源加工、描述、标记、检索、存储等技术标准,并分析我国数字图书馆建设标准化的现状.     

应用实时定量PCR进行肿瘤表达研究中内参基因的选择

实时定量PCR(real-time quantitative PCR,RT-qPCR)是检测肿瘤基因表达水平的一种有效方法,在其中应用较多的相对定量方法需要一种能够在不同的组织、甚至不同的实验条件下表达恒定的理想的内参基因.但是很多研究都已经表明内参基因的表达是可变的.所以为了获得适用于肿瘤表达研究的内参基因,越来越多的研究在近期涌现出来.该文将会对近期关于肿瘤表达研究中内参基因选择的文章进行综述.     

The linear relationship between cigarette tar and nicotine yields: regulatory implications for smoke constituent ratios

Cigarette smoke analyte yields are often expressed as ratios relative to tar or nicotine yields, usually to compare different products or to estimate human uptake of smoke in relation to nicotine uptake measurements. The method, however, can lead to distorted interpretations, especially in the case of ratios from ultra-low tar yield cigarettes. In brief, as tar yields decrease below the 5–6 mg per cigarette range, the tar-to-nicotine ratio (TNR) decreases rapidly in a non-linear fashion. If, however, the nicotine yield, rather than the ratio, is plotted versus the tar yield, the non-linearity disappears and a straight line is obtained, with a slight positive intercept for nicotine on the ordinate. Unlike the ratio, the slope appears to depend only on the concentration of the nicotine in the blend and does not appear to vary with smoking parameters such as puff volume, puff interval or length smoked or with cigarette design parameters such as length, circumference or the amount of filtration or filter ventilation. Therefore, such a slope is analogous to the TNR although, unlike that ratio, it is invariant. Even more simply, the concentration of the nicotine in the blend, at least for American blend-style cigarettes, provides a similar index.     

Spatial summation properties of the human ocular following response (OFR): evidence for nonlinearities due to local and global inhibitory interactions

Ocular following responses (OFRs) are the initial tracking eye movements that can be elicited at ultra-short latency by sudden motion of a textured pattern. A recent study used motion stimuli consisting of two large coextensive sine-wave gratings with the same orientation but different spatial frequency and moving in (1/4)-wavelength steps in the same or opposite directions: when the two gratings differed in contrast by more than about an octave then the one with the higher contrast completely dominated the OFR and the one with lower contrast lost its influence as though suppressed [Sheliga, B. M., Kodaka, Y., FitzGibbon, E. J., & Miles, F. A. (2006). Human ocular following initiated by competing image motions: Evidence for a winner-take-all mechanism. Vision Research, 46, 2041-2060]. This winner-take-all (WTA) outcome was attributed to nonlinear interactions in the form of mutual inhibition between the mechanisms sensing the competing motions. In the present study, we recorded the initial horizontal OFRs to the horizontal motion of two vertical sine-wave gratings that differed in spatial frequency and were each confined to horizontal strips that extended the full width of our display (45 degrees ) but were only 1-2 degrees high. The two gratings could be coextensive or separated by a vertical gap of up to 8 degrees , and each underwent motion consisting of successive (1/4)-wavelength steps. Initial OFRs showed strong dependence on the relative contrasts of the competing gratings and when these were coextensive this dependence was always highly nonlinear (WTA), regardless of whether the two gratings moved in the same or opposite direction. When the two gratings moved in opposite directions the nonlinear interactions were purely local: with a vertical gap of 1 degrees or more between the gratings OFRs approximated the linear sum of the responses to each grating alone. On the other hand, when the two gratings moved in the same direction the nonlinear interactions were more global: even with a gap of 8 degrees -the largest separation tried-OFRs were still substantially less than predicted by the linear sum. When the motions were in the same direction, we postulate two nonlinear interactions: local mutual inhibition (resulting in WTA) and global divisive inhibition (resulting in normalization). Motion stimuli whose responses were totally suppressed by coextensive opponent motion of higher contrast were rendered invisible to normalization, suggesting that the local interactions responsible for the WTA behavior here occur at an earlier stage of neural processing than the global interactions responsible for normalization.     

腹部磁共振规范化扫描方案的应用初探

目的：探讨并制定上腹部规范化磁共振检查方案及其磁共振技术质控标准。方法分别选取随机组250例,平扫50例,平扫后马上增强200例,优化组250例,平扫42例,平扫后马上增强208例,从预约、准备、摆位及定位、序列的规范化、附加技术的应用、诊断信息的满足情况等五个方面共30个项目入手细化工作,并将所得影像信息进行评分及统计学分析。结果优化组评分项目达标率明显高于随机组,且各评分项目的平均值也整体高于随机组,除了D10,且两组对比,差异具有统计学意义,除了C5、D4、D6、D8、D9、D10、E3、E4、E5。各评分大项目也高于随机组,两组对比,差异具有统计学意义。优化组及随机组AA平均值、最大值、最小值分别为（27±0．097）分、30分、21分;（22．08±0．168）分、28分、15分,两组对比,差异具有统计学意义。结论实行腹部磁共振规范化扫描,优化了检查流程及图像质量,缩短了检查时间,提高了检查的成功率。     

谈医院药房质量管理的规范化建设

目的:探讨医院药房规范化管理。方法:介绍我院根据《湖南省药品使用质量管理规范(试行)》标准创建规范化药房的具体做法。结果与结论:只要医院各级领导认识到位,高度重视,措施得力,加强药房硬件、软件建设,建立并完善规范化的管理体系,全体员工共同努力,就能达到药房质量管理规范化目标。