常用生理参数的测量原理

随着医学事业的发展,监护仪得到广泛的运用,就医用监护仪常用生理参数的工作原理简述如下。     

去除白细胞输血的临床意义

目的:评估去除白细胞输血的临床应用价值。方法:251例患者接受了去除白细胞红细胞悬液761U,(每人1￣8U不等),对其中200U红细胞悬液滤除白细胞前、后分别进行白细胞计数和血红蛋白测定,并对其输血反应进行了观察。结果:发现应用白细胞滤器后,其白细胞数比过滤前显著减低,过滤前、后白细胞数分别为(6.16±1.44)×109/L与(0.12±0.10)×109/L(P<0.01),血红蛋白过滤前、后无显著性差异,分别为:(161.58±23.31)g/L与(157.84±22.35)g/L,P>0.05。251例接受去白细胞受血者均未出现输血反应。结论:白细胞滤器能有效去除白细胞,去除白细胞能减少非溶血性输血反应。     

Pathological variables determining the prognosis of non-Hodgkin''s lymphomas

The aim of the study was to assess the role of pathological grade, cell proliferation, ploidy, immunophenotype and site in determining the prognosis of non-Hodgkin's lymphomas. Of particular interest was the relative value of grades derived from the Kiel classification as opposed to the National Cancer Institute (NCI) working formulation. The study consisted of 181 cases, treated in a relatively uniform way over an 18-month period spanning 1986. Using life table analysis, both NCI working formulation grade and Kiel grade correlated strongly with survival. However, the differences between grades were entirely due to an excess of early deaths in the high-grade and intermediate-grade categories. In patients surviving greater than 0.1 years (37 days), phenotype, site, ploidy and cell proliferation had no effect on survival. There was no evidence that intermediate-grade tumours, when subdivided into Kiel low- and high-grade types, differed in survival from tumours graded as low- or high-grade by both methods. However, NCI working, formulation high-grade tumours, especially those with a high proliferation rate, formed a group with a very high likelihood of death within 0.1 years.     

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。     

抑郁患者血清皮质醇与血压在应激前后的变化

目的研究抑郁患者血清皮质醇浓度、血压在应激前后的变化以及它们之间的关系。方法分别在安静状态、心理应激状态和心理应激后 (恢复状态 )测量抑郁组和对照组的血清皮质醇浓度、血压 ,比较两组上述指标的差异 ,以及心理应激前后的变化。心理应激以规定时间内的计算试验模拟 ,血清皮质醇以酶联免疫试验检测 ,血压为常规检测。结果 1.皮质醇 :抑郁组在安静状态、应激状态、恢复状态的皮质醇浓度显著高于对照组 (P <0 .0 5 ) ,抑郁组应激前后皮质醇浓度的波动显著小于对照组 (P <0 .0 5 )。2 .收缩压 :安静状态和恢复状态时抑郁组的收缩压显著高于对照组 (P <0 .0 5 ) ,应激状态时两组无统计学差异 ;应激前后收缩压的波动两组无统计学差异。 3 .舒张压 :抑郁组在安静状态时舒张压显著高于对照组(P <0 .0 5 ) ,在应激状态和恢复状态时两组无统计学差异 ;应激前后舒张压的波动两组无统计学差异。结论抑郁患者存在基础血压升高 ,此现象可能与抑郁患者血清皮质醇浓度升高有关。     

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。     

一种具有高信噪比的脉搏波光电传感器的研制

目的：探讨研制一种生理信号光电传感器。方法：利用光电传感器检测通过指端毛细血管后的光强度的变化，将光信号转换成电信号，再经过电信号1/V转换、放大、滤波处理。结果：获得了清晰稳定的指端容积脉搏波。结论：高信噪比的光电传感器可用作于临床监测和生理信号分析处理系统。     

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.