人心连续组织切片的计算机三维重建

用表面重建法对人心连续组织切片进行了三维重建，重建中应用了火棉胶断面切片技术及图像拟合与插值处理，与以往的解剖断面重建比较，图像更加清晰、逼真，可从不同观察心脏的外部轮廓与内部结构。作为三维重建的基础性研究，可为心血管影像诊断提供解剖形态学依据和可靠的三维软件。     

高能重带电粒子束平均能量计算的一个简单公式

本文提出了一个计算高能重带电粒子束平衡能量的简单公式。在计算重带电粒子放射治疗剂量时，用此公式可获得与平均能量有关的物理量的解析表达式，用此公式计算了入射铝内10-MeV的质子束的平均能量，并与相应的实验数据作了比较，比较表明，本文提出的公式在相当大的能量范围内能够精确地预言重带电粒子的平均能量，此外，还计算了在水中在100-MeV、150-MeV和200-MeV的质子束的平均能量。     

Cx43在造血调控及重建中的作用

目的:采用条件性基因敲除技术构建造血系统间隙连接蛋白43(Cx43)基因敲除(Cx43~(-/-))小鼠模型,并探讨Cx43在维持造血细胞自我更新及功能稳定中的作用。方法:将引进的2对转基因小鼠Cx43 loxP/loxP和Lyz-Cre/+杂交,选取F1雌性子代Cx43 loxP/-_Lyz-Cre/+与雄性Cx43 loxP/loxP合笼回配,提取所获得子代小鼠鼠尾组织基因组DNA,采用PCR方法鉴定小鼠基因型,RT-PCR方法筛选Cx43~(-/-)小鼠,同时分析小鼠不同器官中Cx43基因的表达差异;该类小鼠经5-氟尿嘧啶(5-FU;125 mg/kg)处理,在化疗前及化疗后第5、10和15天经眼球取血分析其血象变化。Cx43~(-/-)及Cx43~(+/+)小鼠予7.5 Gy(~(60)Co-γ)的致死量照射,剂量率1 Gy/min,照射后6 h分别给予事先准备就序的骨髓细胞,每只3×10~6细胞于尾静脉注入,2周后处死小鼠检测造血是否重建:分离股骨切片后,收集骨髓细胞进行细胞表型分析(选用的单抗为CD45R、Gr-1、CD4、 CD8a、TCRαβ、Mac-1、抗sIgM、TER119、Sca-1及CD117);同时进行体外造血细胞集落实验观察造血细胞的体外增殖能力。结果:本研究通过2种转基因小鼠间杂交和回交,成功获得造血系统选择性Cx43基因敲除小鼠;该类小鼠骨髓及外周血细胞无Cx43表达,参与造血的组织,如肝脏和脾脏中Cx43表达也显著下调(P0.01),而心脏和肾脏的Cx43表达则无影响,小鼠成年后外周血象分析并无明显异常,但应急代偿能力下降,经5-FU处理后,其造血功能恢复显著减缓,处理15 d后,Cx43~(+/+)小鼠造血功能已接近正常水平,而Cx43~(-/-)小鼠仍无明显的恢复迹象,血红蛋白、白细胞及血小板仍处低位,2者差别有统计学显著性(P0.01);体外集落试验也证实Cx43~(-/-)小鼠造血干/祖细胞的增殖能力下降,其CFU-GM或CFU-E集落数均明显少于Cx43~(+/+)小鼠(P0.01),但流式细胞术结果显示,Cx43~(-/-)小鼠骨髓中Lin~-/c-Kit~+/Sca-1~+细胞亚群数量与Cx43~(+/+)小鼠相比差异并无统计学显著性;Cx43~(-/-)小鼠在化疗或移植后其骨髓造血功能重建均延迟,且化疗15 d后骨髓切片及涂片均证实其骨髓中造血细胞增生程度明显降低,脂肪组织显著增多,而且T、B细胞发育也有异常。此外,其外周血中CD4~+CD8~+细胞比例比野生型小鼠增多(P0.05),但CD4~+T细胞显著减少(P0.01),尤其是TCRαβ亚群细胞减少最为明显(P0.01)。同样,Cx43~(-/-)小鼠外周血中CD45R~+sIgM~-细胞亚群比例与野生型小鼠相比显著减少(P0.01)。结论:骨髓中Cx43基因表达在造血干/祖细胞发育(尤其是应急状态时)具重要作用,敲除Cx43基因后造血干/祖细胞增殖减缓,造血及免疫重建功能受损。     

A Computer Reconstruction of the Entire Coronary Arterial Tree Based on Detailed Morphometric Data

A rigorous analysis of blood flow must be based on the branching pattern and vascular geometry of the full vascular circuit of interest. It is experimentally difficult to reconstruct the entire vascular circuit of any organ because of the enormity of the vessels. The objective of the present study was to develop a novel method for the reconstruction of the full coronary vascular tree from partial measurements. Our method includes the use of data on those parts of the tree that are measured to extrapolate the data on those parts that are missing. Specifically, a two-step approach was employed in the reconstruction of the entire coronary arterial tree down to the capillary level. Vessels > 40 μm were reconstructed from cast data while vessels < 40 μm were reconstructed from histological data. The cast data were reconstructed one-bifurcation at a time while histological data were reconstructed one-sub-tree at a time by “cutting” and “pasting” of data from measured to missing vessels. The reconstruction algorithm yielded a full arterial tree down to the first capillary bifurcation with 1.9, 2.04 and 1.15 million vessel segments for the right coronary artery (RCA), left anterior descending (LAD) and left circumflex (LCx) trees, respectively. The node-to-node connectivity along with the diameter and length of every vessel segment was determined. Once the full tree was reconstructed, we automated the assignment of order numbers, according to the diameter-defined Strahler system, to every vessel segment in the tree. Consequently, the diameters, lengths, number of vessels, segments-per-element ratio, connectivity and longitudinal matrices were determined for every order number. The present model establishes a morphological foundation for future analysis of blood flow in the coronary circulation.     

Confocal observation of senile plaques in Alzheimer's disease: Senile plaque morphology and relationship between senile plaques and astrocytes

Senile plaques In the brains of Alzheimer's disease (AD) were examined by confocal laser scanning microscopy (CLSM) with the following three findings. First, in sections stained with Congo red, the serial CLSM images of optical sections clearly revealed that a classic plaque is composed of a plaque core and a corona. Radially arranged process-like structures, corresponding to bundles of amyloid fibrils, formed amyloid cores and stronger signals were detected in the center of some cores. Second, in sections stained with Congo red and anti-gllal fibrillary acidic protein (GFAP), reactive astrocytes were found around the senile plaques and many astrocytlc processes surrounded the plaque cores and some processes had penetrated into them. Third, three-dimensional reconstruction on classic plaque revealed that the surface of classic plaque showed a 'coral-like' appearance.     

Microwave Spectroscopy of Myocardial Ischemia and Infarction. 2. Biophysical Reconstruction

The proposed dielectrical relaxation model of the myocardium in the microwave spectrum has been verified both on test solutions and on normal canine myocardium. Furthermore, the model was utilized to reconstruct the changes in tissue properties (including myocardial bulk resistance and water content) following myocardial acute ischemia and chronic infarction. It was shown that the reconstructed myocardial resistance and water content correlate dynamically with the process of the development of acute myocardial ischemic injury. In chronic cases the reconstructed resistance and water content of infarcted myocardium are significantly different from that of normal myocardium: the resistance is lower and water content is higher than in normal myocardium. © 2000 Biomedical Engineering Society. PAC00: 8764-t, 8719Xx     

气管组织工程的研究策略及其展望

气管组织工程是近10年来国内外研究的热点和难点问题,取得了一些进展.但如何更好地遴选基质材料、实现种子细胞共培养、上皮化以及再血管化来构建组织工程化气管仍需要不断寻求新的研究思路和策略.本文从气管重建和理想化气管替代物的角度,回顾了近年来在组织工程气管方面的研究进展,并对未来的研究作出展望.     

Four-Dimensional Computerized Tomography （4D-CT） Reconstruction Based on the Similarity Measure of Spatial Adjacent Images

Objective：To investigate the feasibility of a 4D-CT reconstruction method based on the similarity principle of spatial adjacent images and mutual information measure. Methods：A motor driven sinusoidal motion platform made in house was used to create one-dimensional periodical motion that was along the longitudinal axis of the CT couch. The amplitude of sinusoidal motion was set to an amplitude of ±1 cm. The period of the motion was adjustable and set to 3.5 s. Phantom objects of two eggs were placed in a Styrofoam block, which in turn were placed on the motion platform. These objects were used to simulate volumes of interest Undergoing ideal periodic motion. CT data of static phantom were acquired using a multi-slice general electric （GE） LightSpeed 16-slice CT scanner in an axial mode. And the CT data of periodical motion phantom were acquired in an axial and cine-mode scan. A software program was developed by using VC ＋ ＋ and VTK software tools to resort the CT data and reconstruct the 4D-CT. Then all of the CT data with same phase were sorted by the program into the same series based on the similarity principle of spatial adjacent images and mutual information measure among them, and 3D reconstruction of different phase CT data were completed by using the software. Results：All of the CT data were sorted accurately into different series based on the similarity principle of spatial adjacent images and mutual information measures among them. Compared with the unsorted CT data, the motion artifacts in the 3 D reconstruction of sorted CT data were re- duced significantly, and all of the sorted CT series result in a 4D-CT that reflected the characteristic of the periodical motion phantom. Conclusion：Time-resolved 4D-CT reconstruction can be implemented with any general multi-slice CT scanners based on the similarity principle of spatial adjacent images and mutual information measure. The process of the 4D-CT data acquisition and reconstruction were not restricted to the hardware or software of the C     

CT三维重建在侧颅底的应用研究

目的 探讨CT三维重建在侧颅底的应用价值。方法 15例健康成人在Picker5000全身CT机上行连续轴位扫描，将扫描获得的原始数据输入Voxel Q图像后处理工作站，采用表面阴影法(surface shaded display，SSD)进行三维重建。结果 侧颅底CT三维重建能清楚显示正常侧颅底孔、裂和重要的骨性标志。重建的结构可整体显示或切割后单独显示，两均可在三维空间绕任意轴旋转任意角度。结论 三维CT能立体而直观的显示侧颅底骨性结构，有利于侧颅底外科手术方案的设计。     

复杂胸椎骨折中CT图像三维重建的应用探讨

目的直观立体地显示复杂胸椎骨折的图像，探讨螺旋CT医学图像三维重建在复杂胸椎骨折诊断中的价值及其对手术的指导意义。方法对92例胸椎骨折患者采用螺旋CT进行薄层扫描和三维重建进行诊断。CT扫描全部采用Siemens SOMATOM Sensation16型多排高速螺旋CT机，1．0mm层厚。扫猫所得断层资料通过网络传送至计算机工作站进行处理，采用Window．NT3．51平台上Insisht三维重建软件进行三维重建。结果三维CT图像能够围绕X轴和Z轴任意旋转、切割以从不同角度观察，能够清晰显示复杂的胸椎骨折和狭窄椎管的解剖形态特点。结论三维CT重建在胸椎骨折方面具有很大的临床应用价值，有助于提高脊柱骨折手术的安全性和精确性并对患者预后的估计提供帮助。