光纤温度传感器在永磁共振磁体温控系统中的应用

光纤温度传感器因其在测量和传递信号部分没有电磁的参与,完全不受电磁的干扰。它的抗电磁干扰(EMI/RFI)特性使其具有传统温度传感器无法比拟的应用优势。光纤温度传感器测温是最新的温度测量技术,在强电磁环境下正在取代传统的电介质测温方式。在医疗、核电、工业测温领域有着广阔的发展前景。本文将此新型温度传感器应用于医用磁共振成像系统的永磁体温度控制,详细介绍其工作原理、系统实现并指出其应用优势。     

慢性乙醇中毒性周围神经病大鼠的单纤维肌电图研究

目的观察单纤维肌电图（single fiber electromyography，SFEMG）对慢性乙醇中毒性周围神经病的早期诊断作用。方法建立慢性乙醇中毒性周围神经病大鼠模型，在实验开始后第8，12，16周对大鼠腓肠肌进行SFEMG检测，观察肌纤维密度（FD）、颤抖值（jitter）的变化。结果第8周，第12周SFEMG对乙醇组大鼠坐骨神经检测结果未见异常；第16周SFEMG检测结果显示乙醇组大鼠的MCD和FD值均增大，与对照组比较，差异有显著性（P〈0．05），并且出现电位对阻滞。结沦SFEMG可用于早期诊断慢性乙醇中毒性周围神经病，灵敏性较高.     

磁共振弥散成像在弥漫性轴突损伤诊断中的应用

磁共振弥散成像是通过水分子弥散差异成像,反映水分子弥散运动状态。由于成像原理不同于传统磁共振,故弥散成像对中枢神经纤维束的解剖结构改变较为敏感,从而成为弥漫性轴突损伤诊断的重要技术。弥散加权成像能通过突出弥散效应显示损伤灶;弥散张量成像能反映各向异性矢量,更加敏感地显示损伤灶,并可通过神经纤维束成像显示轴突损伤。弥散成像不仅提高了弥漫性轴突损伤的诊断,还有利于判断伤情及预后。该作者对以上问题作一综述。     

妊高征孕妇血管内皮细胞形态及功能变化的研究

本实验在体外培养出正常的人血管内皮细胞系，然后将妊高征孕妇血清与其共同培养，再对内皮细胞进行张力纤维和细胞粘附分子的染色。实验结果表明：妊高征孕妇血清可诱发血管内皮细胞产生大量张力纤维，并且破坏内皮细胞单层结构的完整性，从而引起血管内皮细胞的损伤。妊高征孕妇血清可以在内皮细胞表面诱发产生大量的细胞粘附分子，使得内皮细胞易从基质上丢失，且血液细胞大量附着于血管壁，造成内皮细胞的损伤。本实验提出了妊高征的病理发生过程，为妊高征的防治提供了理论依据。     

膳食纤维改善老年便秘作用的研究

目的探索在老年人中开展增加膳食纤维摄入量改善便秘的方法,为在老年人群中广泛开展相关干预奠定基础。方法通过专科医院收集老年便秘患者,采用双盲随机对照试验,在试验组进行定量增加膳食纤维的干预,对照组食用安慰剂。应用SPSS11.5软件分析自身前后及组间便秘程度的改善。结果试验组自身前后的排便次数、排便状况、粪便性状均改变(P<0.01);试食后组间的排便次数、排便状况、粪便性状也均有统计学意义(P<0.01)。结论通过定量增加膳食纤维的摄入,可以达到改善老年人便秘的作用。     

The occurrence and histochemical characterization of giant fibers in the muscle of growing and adult animals

Summary Giant fibers in porcine muscle have a variable reaction for DPNH-TR, a very negative reaction for amylophosphorylase and a very positive reaction for ATPase. This unusual histochemical reaction pattern, together with the finding that giant fibers occur in the muscle of adult animals, argues against their being the classical Wohlfart B fiber. The association of giant fibers with animal stress-susceptibility and muscle pathology is discussed.Published with the approval of the Director of the Wisconsin Agricultural Experiment Station, Department Meat and Animal Science Manscpt. No. 497. This investigation was supported in part by the Graduate School Research Committee, Univ. of Wisconsin, in part by Public Health Service Grant No. UI00266-10 from the National Center for Urban and Industrial Health, in part by Armour Food Research Laboratories and in part by the American Meat Institute Foundation.     

Toxocara canis and lead alter consummatory behavior in mice

Ingestion of palatable and unpalatable solutions was measured in adult mice to which had been administered the common parasite of the dog, Toxocara canis alone, or in combination with lead. In addition, response to hot plate and susceptibility to electroconvulsive seizure were also measured. Results from the palatability test indicated that either lead or Toxocara may alter the mouse's mode of interacting with its environment. However, the two agents in combination interacted in their effects on consummatory behavior. Results from the hot plate and ECS measures were less clear with respect to how lead and/or Toxocara influence temperature reactivity and seizure susceptibility. Histological examination of the CNS in parasite infected animals revealed Wallerian Type degeneration of fiber pathways including the corpus callosum, olfactory tract, and cerebellar penduncles.     

Mapping the orientation of intravoxel crossing fibers based on the phase information of diffusion circular spectrum

A new method is presented to map the orientation of intravoxel crossing fibers by using the phase of the diffusion circular spectrum harmonics. In a previous study [Zhan, W., Gu, H., Xu, S., Silbersweig, D.A., Stern, E., Yang, Y., 2003. Circular spectrum mapping for intravoxel fiber structures based on high angular resolution apparent diffusion coefficients. Magn. Reson. Med. 49, 1077-1088], we demonstrated that the magnitude of the 4th-order harmonic of the diffusion circular spectrum can be used to identify the existence of fiber crossings. However, the orientation of the intravoxel crossing fibers remained unknown. This study extends the diffusion circular spectrum mapping method so that it is able to identify the orientation of the intravoxel crossing fibers by utilizing the phase information of the circular spectrum. In general, the phase of the circular harmonic determines the rotation of the apparent diffusion coefficient (ADC) profile on the sampling circle that is spanned by the major and medium eigenvector of the diffusion tensor and thus can be used to determine the orientation of the crossing fibers. Simulation results show that the regular tensor-based major eigenvector maps have obvious artifacts in the fiber-crossing area, whereas the estimated crossing fibers by the proposed method are much more consistent with the orientation of the actual intravoxel fibers. Diffusion MRI experiments were performed on five healthy human brains using a 3T scanner. The brain regions with fiber crossings were selected by thresholding the magnitudes of the 4th-order circular spectrum map. Intravoxel crossing fibers were estimated by the phase of the 4th-order harmonic for each voxel within these areas. The estimated intravoxel crossing fibers demonstrated a clear consistency with the orientations of fiber tracks in the surrounding tissues, reducing the fiber orientation discontinuity of the regular major eigenvector map.     

Dietary fiber in conservative management of chronic renal failure

Conservative management of chronic renal failure has included a variety of dietary manipulations. Supplementation of dietary fiber to reduce adverse symptoms is a novel approach, but whether it can make an effective clinical impact is yet undetermined. This commentary accompanies a brief report of improved well-being during fiber supplementation. It explains some of the background thinking and early trials of fiber supplementation in chronic renal failure patients.