基于氢廓清骨血流自动测试仪的研制

采用氢廓清技术，研制了一种以８０Ｃ５１单片机为控制核心的骨血液自动测试仪，该仪器能自动监控氢廓清过程，完成采样数据除噪，并根据ＦＩＣＫＳ原理数据进行回归分析处理计算并显示打印出局部血流量，操作过程简便，测试精度高。     

诱发电位评价脑组织血流量的实验研究

目的:观察实验性大鼠脑损伤后不同时相点大脑皮层体感诱发电位(sensorysomaticevokedpotentials,ssep)和局部血流量(regional cerebral blood flow,rCBF)的变化.方法:用流体冲击装置制作中度脑损伤模型SYD4200型神经诱发电位诊断系统监测皮层体感诱发电位,氢清除法测定大脑局部血流量.结果:中度脑损伤后rCBF明显低于伤前和正常对照组;大脑皮层体感诱发电位的潜伏期明显延长;结论:SEP的变化与脑血流量有着一定的关系,一定程度上SEP的变化可反映脑损伤后血流量的变化.     

脑血流自动调节功能的三单元模型

目的建立一个三单元集中参数模型来模拟脑血流的自动调节功能。方法根据Bloor的实验数据拟合了一条在脑血流自动调节功能中,反映脑血流量和平均动脉压之间关系的三次曲线,然后利用这一拟合曲线来确定模型中的不定常电阻元件。结果利用这一模型,对不同压力变化情况下的脑血流量变化进行了数值模拟。通过与实验数据进行了对比,发现这一不定常三单元模型能够较为简单地模拟脑血流自动调节功能。结论经过改造的这一三单元集中参数模型可以为脑血流自动调节功能及脑血管疾病的研究提供帮助。     

中国人股骨上段几何特征研究

目的研究股骨近端几何形态的统计规律,以改善现有的人工关节设计.方法成人尸体股骨480根,正侧位X光片摄片获得原始成像,用计算机数字图像技术结合测量21个参数,对股骨上段髓腔曲线进行拟合和统计.对股骨髓腔截面形态进行自动提取,并采用圆锥曲线拟合、二次曲线简化、形心曲线拟合等数学方法,将股骨髓腔截面形态简化为长短轴、形心轴线等几个参数.结果获得480例股骨上段参数的统计数据,150例股骨上段髓腔截面的长短轴以及截面形心的曲线拟合方程并对截面的长短轴和形心曲线方程进行了分类.讨论本研究对股骨髓腔21个参数做了大量统计分析,应用模式识别的方法将曲线形状参数以分类定为6种,并选出截面形心的曲线拟合方程,这些都为假体柄部的设计提供了科学的依据,为三维建模提供了基础,使得CAD优化设计成为可能.     

股骨头坏死病灶清除计算机辅助系统配准模块和导航模块的建立

背景：股骨头坏死的传统治疗方法首先要进行病灶清除,这个过程手术时间长,很难彻底清除病灶且容易损伤正常骨组织。 目的：建立股骨解剖结构的几何模型,并在此基础上开发股骨头缺血性坏死病灶清除计算机辅助系统的配准模块和导航模块。 方法：首先应用MC算法,建立股骨解剖结构的几何模型;然后应用点和表面相结合的配准方法进行患病股骨与股骨几何模型之间的配准;最后进行了股骨头坏死病灶清除计算机辅助软件系统的设计,并对整个系统的精度进行实验验证。 结果与结论：开发的股骨头坏死病灶清除计算机辅助软件系统的误差在3 mm以下,基本满足该类骨科手术的精度要求。     

药物肝清除一室扩散模型的参数估计

对药物肝清除一室扩散模型，给出了一组利用最小二乘法估计动力学参数的计算公式，并对流出肝脏的药物浓度关于时间变化的曲线形状进行了讨论。     

QT离散度计算机自动测量

目的介绍一种计算机自动测量QT离散度方法.方法采用最小二乘法拟合直线识别T波终点.结果初步分析了175例心电图,其中100例为体检正常人,高血压30例,高血压左室肥厚35例,急性心肌梗塞10例.结论计算机QT离散度自动测量具有省时、省力、重复性好和计算精确.     

慢性肾脏疾患病人的残余肾皮质灌注

对32例球性肾炎、肾盂肾炎、进行性晚期肾硬代或肾同种异体移植排斥引起的慢性肾脏疾患采用最可靠的方法分析了病肾的氙清除,即使氙清除之快速成分仅为总血流的10％时,这种方法也提供了对资料的极为满意拟合。用这种方法已经证实了慢性肾疾患中平均肾血流量和肾血流的进入最快的或皮     

在体使用的多丝氢电极

本文描述了一种测量极小体积内氢气分压的多丝表面电极,目的是在体记录氢廓清率曲线,分析毛细血管的血液流动,该电极是由被任意融合在一个玻璃芯内的8个直径都是15μm的铂导线组成。提出了改进克拉克型极谱法传感器灵敏度和稳定性的方法。研究了该电极离体和在体特性并与进行气体极谱法测量的不同模型所预示的特性作了关键性的比较。电极的高稳定性和低漂移以及它所具有的小的捕捉体积(半径为32μm的半球)意味着它可以可靠地用来对氢廓清率曲线进行准确、重复     

股骨上段髓腔的计算机测量方法

为研究股骨上段髓腔载面几何形态的统计规律，以计算机图像处理的方法和对股骨上段髓腔截面形态进行自动提取，并提出圆锥曲线拟合的参数化数学方法，分别用计算机方法和人工方法对10例股骨上段髓腔截面进行测量，从统计结果看，计算机测量结果与人工测量结果无显著型差异（P＞0．05），不仅减少了人为误差，且能以计算机自动完成，适合于大批量的形态计量。     

The clearance of Xenon-133 following its parenchymal injection: a rapid method for estimating functional liver blood-flow

Portal venous flow, total hepatic blood-flow and hepatic artery flow were measured in healthy dogs by electromagnetic flowmetry and a double indicator dilution technique. Functional liver blood-flow was measured by the double indicator dilution technique. Functional hepatic blood-flow did not correlate with portal venous flow, total hepatic blood-flow or hepatic artery flow, measured by either electromagnetic flowmetry or a double indicator dilution technique. There was a good correlation (r = 0.83, P less than 0.001) between functional hepatic blood-flow and liver blood-flow, measured by the clearance of Xenon-133 injected directly into the liver parenchyma. It is concluded that the clearance of Xenon-133, injected directly into the liver parenchyma, is a rapid and simple method for measuring functional hepatic blood-flow.     

不同给氢方式对兔氢气代谢的影响*☆

背景：不同给氢方式均可对缺血再灌注损伤产生治疗作用,目前尚缺乏不同给氢方式对机体氢气代谢影响的研究。 目的：比较等体积氢水腹腔、静脉注射及氢气腹腔注射对兔氢气代谢的影响,以利于提供更优化的氢气治疗方案。 方法：20只新西兰大白兔在监测呼气氢气基础值后,依次予以饱和氢气生理盐水、氢气10 mL/kg腹腔注射及氢水10 mL/kg 10 min内静脉泵入,持续监测呼气氢气浓度,等降至基础值并稳定30 min以上后再进行下一方式给氢干预。记录各种给氢方式呼气氢气浓度的达峰时间、峰浓度,计算半衰期和曲线下面积,比较3种给氢方式对呼气氢气浓度的影响。 结果与结论：腹腔注射氢水、氢气及静脉注射氢水3种方式达峰时间分别为(3.25±1.80),(17.8±6.48)和(7.45±1.39) min,差异有显著性意义(P < 0.01);半衰期分别为(7.40±2.09),(141.50±85.01)和(1.20±0.37) min,差异有显著性意义(P < 0.01);较基础值增加的曲线下面积分别为(302.17±221.90),(5 234.29±2 681.18)和(209.51±104.49) ppm•min,差异具有显著性意义(P < 0.01)。提示腹腔注射氢水、氢气均可迅速提高呼气氢气浓度,腹腔注射氢气能长时间维持呼气氢气高浓度。 关键词：氢气;饱和氢气生理盐水;代谢;腹腔注射;静脉注射 doi:10.3969/j.issn.1673-8225.2012.11.029     

Cyclical changes in endogenous overnight creatinine clearance during the third trimester of pregnancy

To investigate the pattern of change in endogenous overnight creatinine clearance during the third trimester, 12 healthy women with uncomplicated pregnancies were examined three times a week. Urine was collected overnight from 22.00 to 08.00 hours and analysed for creatinine. Serum was sampled in the morning and analysed for creatinine, beta 2-microglobulin, progesterone and estradiol. The general trend of creatinine clearance was parabolic with a declining level during the last month before term. A sinusoid pattern with minimum values around the time when the women would have had menstruation had they not become pregnant was superimposed on the parabolic trend. A mathematical model (parabolas overlaid with a cosine curve) was constructed and fitted to the data. The cyclical pattern was significant. Serum creatinine showed a pattern with increasing values during the last 4-6 weeks before term and cyclical changes which were also significant. In the individual case the monthly and preterm clearance decrement sometimes was over 50%. Monthly and preterm decreases in creatinine clearance may be quite normal and serial measurements of creatinine clearance are therefore necessary to determine if declining values indicate pathological falls in the glomerular filtration rate.     

Clearance assurance for stereotactic radiosurgery and radiotherapy

The nature of stereotactic radiotherapy (SRT)/radiosurgery (SRS) requires the use of oblique non-coplanar beams to avoid critical structures and maximize target coverage. These beams are delivered via a combination of gantry, collimator, and couch rotations. Such beam orientations could result in the gantry colliding with the patient or couch. The outcome can be patient injury, damaged equipment, and unrealized treatment. Our objective in this work was to create a treatment planning tool that utilizes each unique patient geometry to quantify clearance for stereotactic beams. Emphasis was placed on developing a general platform that can completely, yet easily, define any user system. Gantry components were described by providing component dimensions to software that generates thousands of surface points. Table components were described as a combination of boxes and measured surface points. During the treatment planning process isocenter coordinates, patient dimensions and beam orientation were specified. Gantry components were then transformed into the table reference frame. The shortest distance between the gantry and patient or couch was computed and compared to a safety margin. This clearance assurance algorithm was developed in response to the need to reduce patient setup time, and to increase the range of potentially useful beams. The software was verified by measuring minimum gantry-table distances at multiple beam orientations and comparing to calculations. Differences between calculated and measured clearances were on the order of 1 cm. The software enabled the safe delivery of noncoplanar oblique beams that are difficult to visualize. The software was used successfully to assure clearance for 50 patients (366 beams). This useful clinical tool became an integral part of the stereotactic quality assurance protocol at St Luke's-Roosevelt Hospital Center.     

Hydrogen peroxide generation from reduced polymer nitroxyls and oxygen

For producing hydrogen peroxide the suitability of stable polymeric nitroxyls as reaction carriers was investigated. These can be hydrogenated to the corresponding hydroxylamines, which are oxidized by oxygen exclusively to hydrogen peroxide and nitroxyls. The yield of hydrogen peroxide was determined in different solvents, at different reaction times and temperatures. Possible side reactions for the decomposition of hydrogen peroxide were investigated. The activation energy for the oxidation of polymeric hydroxylamine with oxygen in DMSO was calculated to be 67 kJ/mol.     

Effect of local warming on forearm reactive hyperaemia

Measurement of minimal vascular resistance has proved useful in quantifying structural changes in regional circulations. Accurate measurement of minimal vascular resistance requires full relaxation of all resistance vessels within the region under examination. The usual procedure in humans involves the measurement of maximal forearm blood-flow following 6-10 min of forearm ischaemia. We conducted this study to find whether forearm skin was fully vasodilated by this procedure. Peak forearm blood-flow was measured by plethysmography in six healthy subjects following 10 min of ischaemia while the arm was at a neutral temperature (33 degrees C) and while the arm was locally warmed to 42 degrees C. Peak reactive hyperaemia blood-flow was significantly elevated by local heating (P less than 0.001) to 79.6 ml 100 ml-1 min-1 from a value of 50.2 ml 100 ml-1 min-1 during normothermia. Peak reactive hyperaemia blood-flow in the contralateral unheated forearm showed no significant change between the two periods of ischaemia (P greater than 0.05). These findings were confirmed in four subjects by laser Doppler velocimetry, which gives a linear index of skin blood-flow. In normothermic conditions, this index rose to 0.89 V following 10 min of ischaemia and to 1.26 V with local warming to 42 degrees C (P less than 0.001). Ischaemia plus local warming did not cause a further significant rise in this index of skin blood-flow (1.35 V, P greater than 0.05). These data suggest that 10 min of ischaemia during normothermia is insufficient to relax fully cutaneous resistance vessels and that maximal forearm blood-flow is underestimated by this procedure.     

Clearance of passively transferred IgE antibody from peripheral blood of mast cell-deficient W/Wv mice

The plasma decay curve of intravenously injected murine monoclonal or conventional anti-DNP IgE antibody was determined in mast cell-deficient W/Wv and their normal littermate +/+ mice. The results show that the clearance of passively transferred IgE was not altered by mast cell deficiency. Possible sites of clearance and/or catabolism of IgE are discussed.     

Raster-scan method for observing physiological entrainment phenomena

A simple raster-scan display, using a small interactive microcomputer with graphics capability, is described and gives visual indication of various entrainment-type phenomena. In particular, almostentrainment and transient behaviour are easily detectable. The display is illustrated using entrainment conditions in heart-rate variability data and blood-flow measurements.     

Capillary permeability in canine myocardium as determined by bolus injection, residue detection

Capillary permeability of 51Cr-EDTA in the canine myocardium was determined by applying: (A) the single injection, external registration method, and (B) the local tissue clearance method, to the intact dog heart of open-chest anesthetized dogs. (A) 51Cr-EDTA was administered into the left anterior descending coronary artery as a bolus injection, and the response curve was recorded by external registration. The capillary diffusion capacity (the permeability-surface area product) for 51Cr-EDTA amounted to 32.5 ml/100 g x min at a capillary extraction of 0.40 and a plasma flow of 73.3 ml/100 g x min. The diffusional permeability coefficient of 51Cr-EDTA was calculated to 1.08 x 10(-5) cm/s, which indicates that the permeability of the capillaries in the myocardium for 51Cr-EDTA is similar to that of continuous capillaries in other tissues. (B) 51Cr-EDTA (3-100 microliters) was injected at a depth of 5 mm into the myocardium of the left ventricular free wall and the residue curve was recorded. The capillary extraction, as determined by the tissue clearance method, was calculated to values 6 times smaller than determined with the single injection, residue detection method. This unreasonably low extraction was probably due to methodological errors inherent to the tissue clearance technique.