D2-43病毒E蛋白在酵母细胞表面的展示

目的：在酵母细胞表面展示登革2型病毒43株(D2—43)的E基因，探索利用酵母表面展示系统建立DNA改组筛选平台的可行性。方法：通过RT-PCR扩增获得D2-43的E基因，将该基因亚克隆至T载体后，再克隆至酵母表面展示载体pYDI，于酿酒酵母EBY100中利用半乳糖进行诱导表达。表达产物采用间接免疫荧光法和FACS进行检测。结果：酵母表面展示产物可与D2-43的腹水抗体特异性地结合；在半乳糖诱导后24h，展示E蛋白的酵母细胞百分数达22．07％。结论：本研究为建立基于酵母表面展示系统的DNA改组筛选平台奠定了基础。     

Combining spin echoes with gradient echoes in the context of the global coherent free precession pulse sequence.

To extend the signal longevity of magnetically excited spins in flowing fluids while in a state of global coherent free precession (GCFP), a refocusing radiofrequency (RF) pulse and bipolar gradient waveforms were combined with the GCFP sequence. The data demonstrate that RF refocusing in the presence of flowing blood is possible, but the improvement in signal amplitude depends on the static magnetic field homogeneity along the direction of motion and the displacement of the spins between the excitation and the RF refocusing pulse, as well as displacement during subsequent RF refocusing pulses. The least amount of phase dispersion and thus the longest lasting signal is obtained with the shortest echo spacing where only one line of data is recorded between two RF refocusing pulses. This approach was successfully used in a phantom and in vivo to image fast and slow blood flow. Depending on the experimental conditions, signal persistence is improved significantly compared to playing the same sequence without RF refocusing, but the improvement is limited by the product of blood flow velocity and the time between RF refocusing pulses.     

二维彩色多普勒显像在下肢静脉血栓诊断中的应用

目的:探讨二维(2-DE)彩色多普勒显像(CDF1)在下肢静脉血栓中的诊断及治疗效果观察中的应用价值。方法:应用ACUSON-128XP10及GE-VIVID7超声仪对来自于血管外科73例98人次(111条)下肢静脉血栓病人进行检查。结果:下肢深静脉完全阻塞57例(62条),部分阻塞3例(4条),少部分再通(<50％)18人次(23条),大部分再通(75％)15人次(17条),完全再通2人次(2条),其中再通人次包含治疗后复查的部分二次及三次复检者及来诊时即为部分再通者。另外,有3例(3条)合并大隐静脉曲张及血栓形成。结论:二维彩色多普勒显像对下肢静脉血栓的阻塞程度、范围及治疗后再通情况可做出较为肯定的诊断,对指导下肢静脉血栓的治疗及预后判断具有重要价值。     

中国部分地区妇幼卫生信息系统的现状分析

本文通过研究卫生 项目地区报表资料和现场调查 ,对项目地区妇幼卫生信息系统的建设及运作情况进行了分析 ,并对报表数据质量进行了评价。分析显示 :卫 项目推动了贫困地区信息系统建设 ,项目地区已建立起系统的妇幼卫生信息管理体系 ,但分析也反映出项目地区妇幼卫生常规报表的数据质量仍存在一定问题。分析结果提示 ,应进一步加强妇幼卫生信息系统建设 ,提高妇幼卫生统计信息专业队伍的业务水平。     

无创伤法联合测定门静脉压力及肝血流评价肝硬化疗效

目的　为临床评价肝硬化疗效提供有价值的手段。方法　采用99Tcm-RBC及99Tcm-MIBI分别测定 16例肝硬化患者治疗前后的肝血流及门静脉压力。前者选择峰时 (T(max) 、半廊清时 (T1/ 2 )、廊清率 (K值 )及肝血流(LBF)等作为观察指标 ;后者以心 /肝 (H/L)比值及门静脉压力 (PVP)为观察指标。结果　治疗前Tmax、T1/ 2 、K值及LBF分别为 1.83± 1.0 4min、5 .3 7± 2 .19min、0 .10± 0 .0 3及 0 .45± 0 .16L/min ,而治疗后分别为 0 .86± 0 .2 0min、3 .80± 1.86min、0 .14± 0 .0 4及 0 .64± 0 .2 0L/min ,治疗前后各项指标均有非常显著性差异 (P <0 .0 1或 0 .0 0 1)。服药前H/L、PVP分别为 0 .73± 0 .16及 3 .0 0± 0 .5 5kPa;治疗后分别为 0 .47± 0 .18及 2 .2 0± 0 .62kPa,与治疗前相比均有非常显著性差异 (均P <0 .0 0 1)。结论　所用测定肝血流及门静脉压力的两种方法均无创伤性 ,用于观察肝硬化疗效有一定价值     

系统性红斑狼疮患者淋巴细胞亚群早期凋亡的初步研究

目的：检测系统性红斑狼疮(SLE)患者外周血单个核细胞(PBMC)中不同细胞亚群发生凋亡的情况，并初步分析其在SLE发病机制中的意义。方法：取28例SLE患者和性别年龄与之相匹配的20个正常对照者。采用淋巴细胞亚群标志、Annexin-V及碘化丙啶三色荧光标记、流式细胞术检测细胞的早期凋亡。结果：SLE患者体内CD3^ T细胞、CD4^ T细胞和CD8^ T细胞的凋亡百分率均显著高于正常对照组(P＜0．05)。同时，SLE患者T淋巴细胞的死亡百分率也高于正常人。经激素治疗一定时间后，这些细胞亚群的凋亡率会进一步升高(P＜0．01)，但CD4／CD8比值恢复至接近正常人。SLE患考体内CDl9^ B淋巴细胞的凋亡或死亡百分率和正常对照组相比均无明显差别，激素治疗对B细胞凋亡和死亡的影响亦不显著。结论：在SLE患者体内主要是T淋巴细胞凋亡增加，但SLE患者淋巴细胞数目减少不仅仅是因为细胞凋亡所致，死亡细胞数目明显升高也是其中一个重要原因。激素治疗可诱导SLE患者T淋巴细胞进一步发生凋亡，并使T细胞亚群比例有所改善。     

Signal-to-noise ratio effects in quantitative cerebral perfusion using dynamic susceptibility contrast agents.

Theoretical and simulation evidence is presented in support of the idea that the optimal manner of determining blood flow from MR perfusion studies is not necessarily obtained by setting experimental conditions to maximize either the arterial input or the measured tissue concentration level for a particular echo time (TE). The noise power in the contrast concentration curve is associated with its peak because of the nonlinear relationship between the contrast concentration and MR signal intensity curves. The optimum signal-to-noise ratio (SNR), SNR(C), for a particular contrast concentration curve can be obtained when the experimental concentration level and TE are adjusted to produce an MR intensity curve whose signal loss is 63% of the precontrast MR signal intensity. It is demonstrated that the stability of the singular valued decomposition (SVD) deconvolution approach to determine blood flow parameters is increased when the tissue curve maximum signal loss is in the range of 40-80%. The accuracy and stability of the SVD-determined blood flow parameters are affected by deviations from these optimum conditions in a manner that depends on the mean transit time (MTT) associated with the residue function. It is recommended that the experimental TE value be set so that neither the tissue nor the arterial curves are placed a region of rapidly deteriorating SNR(C).     

Functional magnetic resonance imaging based on changes in vascular space occupancy.

During brain activation, local control of oxygen delivery is facilitated through microvascular dilatation and constriction. A new functional MRI (fMRI) methodology is reported that is sensitive to these microvascular adjustments. This contrast is accomplished by eliminating the blood signal in a manner that is independent of blood oxygenation and flow. As a consequence, changes in cerebral blood volume (CBV) can be assessed through changes in the remaining extravascular water signal (i.e., that of parenchymal tissue) without need for exogenous contrast agents or any other invasive procedures. The feasibility of this vascular space occupancy (VASO)-dependent functional MRI (fMRI) approach is demonstrated for visual stimulation, breath-hold (hypercapnia), and hyperventilation (hypocapnia). During visual stimulation and breath-hold, the VASO signal shows an inverse correlation with the stimulus paradigm, consistent with local vasodilatation. This effect is reversed during hyperventilation. Comparison of the hemodynamic responses of VASO-fMRI, cerebral blood flow (CBF)-based fMRI, and blood oxygenation level-dependent (BOLD) fMRI indicates both arteriolar and venular temporal characteristics in VASO. The effect of changes in water exchange rate and partial volume contamination with CSF were calculated to be negligible. At the commonly-used fMRI resolution of 3.75 x 3.75 x 5 mm(3), the contrast-to-noise-ratio (CNR) of VASO-fMRI was comparable to that of CBF-based fMRI, but a factor of 3 lower than for BOLD-fMRI. Arguments supporting a better gray matter localization for the VASO-fMRI approach compared to BOLD are provided.     

人力资源管理信息系统的设计与分析

人力资源管理是企业管理的重要基础工作,提高人力资源管理工作的科学性、有效性和效率,是当前人力资源管理工作的客观要求。结合企业人力资源管理的现状,本文讨论了人力资源管理信息系统的设计与开发。本系统能够完成企业员工信息的存储、备份、恢复、添加、删除、查询以及各类相关报表的打印。     

Outcome in Children With Significantly Abnormal Cerebral Blood Flow Detected by Doppler Ultrasonography: Focus on the Survivors

BACKGROUND AND PURPOSE: The Doppler waveform patterns of loss of diastolic flow, appearance of retrograde diastolic flow, or no detectable flow in the cerebral arteries suggest significantly abnormal cerebral blood flow (CBF). A retrospective study was performed to show that significantly abnormal CBF alone, without clinical criteria, is not necessarily specific to brain death in the young pediatric population. PATIENTS AND METHODS: Forty-seven pediatric patients, from newborn to 4 years of age, were found to have significantly abnormal CBF, including 7 patients with loss of diastolic flow, 28 with retrograde diastolic flow, and 23 with no detectable cerebral flow on serial Doppler sonographic examinations. Their clinical data and sonographic results were collected and analyzed. RESULTS: Forty-two patients died, a few of whom had only transient improvement of cerebral flow. All of the patients with no detectable cerebral flow expired. Five patients survived with or without sequelae. Their underlying conditions that caused increased intracranial pressure were treated by medical and/or surgical intervention, and diastolic reversal of CBF corrected within 1 day in all 5. CONCLUSIONS: Although no detectable flow is a lethal sign, pediatric patients with loss or reversal of diastolic flow may survive with prompt and effective treatment. Using Doppler ultrasound to diagnose cerebral circulatory arrest should be done with caution in pediatric patients.