成年大鼠胰岛的体外基因转染

目的 探讨携带外源基因的慢病毒在体外有效感染胰岛及外源基因在胰岛中的表达，为通过移植前向胰岛细胞转入特定的免疫调节分子基因诱导胰岛移植物耐受奠定基础。方法 将目的基因CTLA4Ig导入慢病毒载体pWPTS，构建成pWPTS-CTLA4Ig载体。用磷酸钙沉淀法将pWPTS-EGFP、pWPTS-CTLA4Ig分别和其辅助载体pMD2．G、pCMVΔ8．92共转染293T细胞，收获病毒上清液，测定病毒滴度后感染新分离的胰岛。通过Western Blot测定胰岛培养上清液中CTLA4Ig蛋白的表达。结果 ①成功构建了携带CTLA4Ig基因的慢病毒载体pWPTS-CTLA4Ig；②包装产生的慢病毒Lenti-EGFP、Lenti-CTLA4Ig在体外可以感染胰岛，其中在Lenti-EGFP慢病毒感染的胰岛观察到了绿色荧光，及在Lenti-CTLA4Ig慢病毒感染的胰岛培养上清液中检测到了CTLA4Ig蛋白的表达。结论 慢病毒在体外可以有效感染大鼠胰岛，且携带的外源基因可以在胰岛细胞中稳定表达，其中Lenti-CTLA4Ig慢病毒感染的胰岛为进行胰岛移植并诱导体内特异的胰岛移植物耐受奠定了基础。     

The central pattern generator for vomiting may exist in the reticular area dorsomedial to the retrofacial nucleus in dogs

There is some controversy over whether or not a discrete site that integrates vomiting activities in somatic and autonomic nerves is present in the medulla oblongata. On the basis of our previous studies, we hypothesized that the temporal patterns of muscle contractions in vomiting are generated by a central pattern generator in the retrofacial area of the rostral medulla. To investigate this hypothesis further, the effects of electrical and chemical lesions of the medullary area were observed in decerebrate paralyzed dogs. Efferent activities of the phrenic and abdominal muscle nerves were recorded to recognize fictive vomiting. The right half of the medulla oblongata was transversely severed about 3 mm rostral to the obex. Fictive vomiting responses to vagal stimulation still appeared after hemisection in all 11 dogs. In addition, stimulation of the contralateral reticular area dorsomedial to the retrofacial nucleus produced fictive vomiting even after hemisection. An electrical lesion or injection of kainic acid (0.5–1.0 μl) was applied at the point where reticular stimulation induced fictive vomiting. After this destruction, no activities that corresponded to fictive vomiting could be induced by stimulation of vagal afferents or the reticular site. Salivation was decreased by hemisection, and decreased further, but was not completely abolished, with destruction of the reticular area. Kainic acid is known to selectively destroy neural cell bodies. Therefore, we concluded that neuronal somata in the reticular formation dorsomedial to the retrofacial nucleus play an essential role in the central patterning of vomiting activities in peripheral motor nerves. Received: 10 September 1996 / Accepted: 2 July 1997     

Adaptive motor unit action potential clustering using shape and temporal information

An adaptive algorithm is described that groups motor unit action potentials (MUAPs), detected in a composite EMG signal during signal decomposition, and creates partial motor unit action potential trains (MUAPTs). Data-driven MUAP shape and motor unit firing-pattern based criteria are used to form the clusters. An algorithm for estimating MUAPT temporal parameter, which provides accurate estimates even for partially defined trains, is used to obtain firing-pattern information. No a priori knowledge is required regarding the number of clusters or the distribution of their template shapes. The clustering algorithm when applied to real concentric-needle detected MUAP data provides accurate and useful clustering results. Compared to a classical leader-based algorithm, it provides more robust performance, is better able to estimate the true number of motor units represented in a set of detected MUAPs, and obtains more complete and accurate MUAPTs.     

Genetic dissection of the complex pathological manifestations of collagen disease in MRL/lpr mice

An MRL strain of mice bearing a Fas-deletion mutant gene, lpr, MRL/MpJ-lpr/lpr (MRL/lpr) develops collagen disease involving vasculitis, glomerulonephritis, arthritis and sialoadenitis, each of which has been studied as a model for polyarteritis, lupus nephritis, rheumatoid arthritis and Sjögren’s syndrome, respectively. Development of such lesions seems dependent on host genetic background since the congenic C3H/HeJ-lpr/lpr (C3H/lpr) mice rarely develop them. To identify the gene loci affecting each lesion, a genetic dissection of these complex pathological manifestations was carried out. First, histopathological features in MRL/lpr, C3H/lpr, (MRL/lpr × C3H/lpr) F1 intercross, and MRL/lpr × (MRL/lpr × C3H/lpr) F1 backcross mice were analyzed. Genomic DNA of the backcross mice were subjected to association studies by Chi-squared analysis for determining which polymorphic microsatellite locus occurs at higher frequency among affected compared to unaffected individuals for each lesion. As a result, gene loci recessively associated with each lesion were mapped on different chromosomal positions. We concluded that each of these lesions in MRL/lpr mice is under the control of a different set of genes, suggesting that the complex pathological manifestations of collagen disease result from polygenic inheritance.     

Circadian clock and cell cycle gene expression in mouse mammary epithelial cells and in the developing mouse mammary gland.

Mouse mammary epithelial cells (HC-11) and mammary tissues were analyzed for developmental changes in circadian clock, cellular proliferation, and differentiation marker genes. Expression of the clock genes Per1 and Bmal1 were elevated in differentiated HC-11 cells, whereas Per2 mRNA levels were higher in undifferentiated cells. This differentiation-dependent profile of clock gene expression was consistent with that observed in mouse mammary glands, as Per1 and Bmal1 mRNA levels were elevated in late pregnant and lactating mammary tissues, whereas Per2 expression was higher in proliferating virgin and early pregnant glands. In both HC-11 cells and mammary glands, elevated Per2 expression was positively correlated with c-Myc and Cyclin D1 mRNA levels, whereas Per1 and Bmal1 expression changed in conjunction with beta-casein mRNA levels. Interestingly, developmental stage had differential effects on rhythms of clock gene expression in the mammary gland. These data suggest that circadian clock genes may play a role in mouse mammary gland development and differentiation.     

基于3D Shepp-Logan头部模型的三维医学图像重建仿真

Shepp-Logan头部模型是计算机断层图像重建(CT)领域仿真计算普遍采用的经典模型。我们提出一种新思路—以3D Shepp-Logan头部模型作为三维医学图像重建领域进行仿真实验和算法性能评测的基本参考模型。首先介绍了3D Shepp-Logan头部模型的设计与实现以及仿真投影数据的计算,进而描述了所设计的三维医学图像重建仿真计算过程。数值实验部分给出了基于3D Shepp-Logan头部模型的三维医学图像重建仿真实验。实验结果表明了新思路的可行性和模型计算的准确性。     

An animal model of SARS produced by infection of Macaca mulatta with SARS coronavirus

A new SARS animal model was established by inoculating SARS coronavirus (SARS-CoV) into rhesus macaques (Macaca mulatta) through the nasal cavity. Pathological pulmonary changes were successively detected on days 5-60 after virus inoculation. All eight animals showed a transient fever 2-3 days after inoculation. Immunological, molecular biological, and pathological studies support the establishment of this SARS animal model. Firstly, SARS-CoV-specific IgGs were detected in the sera of macaques from 11 to 60 days after inoculation. Secondly, SARS-CoV RNA could be detected in pharyngeal swab samples using nested RT-PCR in all infected animals from 5 days after virus inoculation. Finally, histopathological changes of interstitial pneumonia were found in the lungs during the 60 days after viral inoculation: these changes were less marked at later time points, indicating that an active healing process together with resolution of an acute inflammatory response was taking place in these animals. This animal model should provide insight into the mechanisms of SARS-CoV-related pulmonary disease and greatly facilitate the development of vaccines and therapeutics against SARS.     

Windows环境下步进电机匀加速的实现与计算机程序设计

本文主要介绍了奔腾计算机和步进电机的接口电路,提出了步进电机匀加速的控制算法,探讨了在 Windows 环境下以 Visual C++实现步进电机匀加速的实现途径和多任务环境下匀加速程序的设计方法。