Growth cones and axon trajectories of a sensory pathway in the amphibian spinal cord

Central axons of sensory ganglion (SG) neurons of the Xenopus tail enter the spinal cord via the ventral roots and travel dorsally and rostrally following a diagonal course within the lateral marginal zone (LMZ) to reach the dorsolateral fasciculus (DLF) (Nordlander et al.: Brain Res., 440:391-395, 1988). Axons are dispersed as they cross the cord. At the DLF they turn and travel together rostrally, sharing the fascicle with axons of primary sensory neurons (Rohon-Beard cells) already present in the tract. In this paper we analyze the growth patterns of the central projections of SG axons in the tail by using HRP applied to proximal branches of tail spinal nerves. Growth cones of the diagonal route are variable in configuration, often bearing processes that spread within the LMZ. Once the DLF, growth cones change shape, becoming distinctly linear. While growth cones navigating the diagonal part of the route never contact or fasciculate with other diagonal SG axons, SG growth cones and axons of the DLF are more closely associated with their fellows. Measurements of the slopes of SG axons in the diagonal route indicated a limited range with a mean of 23 degrees with respect to the cord axis. On the basis of these observations, we conclude that 1) navigational patterns for growth cones of this pathway differ for the diagonal versus the DLF part of its course, and 2) fasciculation is not a mechanism used by SG axons to reach the DLF, but that instead, each axon is able to find its way independently.     

An XPS and SEM evaluation of six chemical and physical techniques for cleaning of contaminated titanium implants

The purpose of the present study was to analyse clinically failed and retrieved implants prior to and after cleaning by means of scanning electron microscopy (SEM) and X-ray induced photoelectron spectroscopy (XPS) as compared to unused controls. Six different chemical and physical techniques for cleaning of contaminated titanium implants were evaluated: 1) rinsing in absolute ethanol for 10 min, 2) cleaning in ultrasonic baths containing trichloroethylene (TRI) and absolute ethanol, 10 min in each solution, 3) abrasive cleaning for 30 s, 4) cleaning in supersaturated citric acid for 30 s, 5) cleaning with continuous CO2-laser in dry conditions at 5 W for 10 s, 6) cleaning with continuous CO2-laser in wet conditions (saline) at 5 W for 10 s. SEM of failed implants showed the presence of contaminants of varying sizes and XPS showed almost no titanium but high carbon signals. XPS of unused titanium implants showed lower levels of titanium as previously reported, probably due to contamination of carbon which increased with time in room air. Cleaning of used implants in citric acid followed by rinsing with deionized water for 5 min followed by cleaning in ultrasonic baths with TRI and absolute ethanol gave the best results with regard to macroscopical appearance and surface composition. However, as compared to the unused implants the results from an element composition point of view were still unsatisfactory. It is concluded that further development and testing of techniques for cleaning of organically contaminated titanium is needed.     

经直肠超声对前列腺癌诊断的价值

目的：本文观察前列腺癌部位声像图特点并与病理对照，以便帮助对前列腺癌诊断及穿刺点的正确选择，提高前列腺穿刺活检阳性率。方法：总结64例经病理证实为前列腺癌的112个部位的经直肠超声声像图，观察有无异常回声肿块和异常血流区域。结果：112个前列腺癌部位其经直肠超声(TRUS)检查发现异常的有90个，占80．4％；TRUS检查未发现可疑之处的为22个，占19．6％。结论：TRUS可作为诊断前列腺癌和前列腺穿刺活检穿刺点选择的重要方法。     

超声对宫角妊娠的诊断及治疗意义

目的 探讨对误诊率高，危害大的罕见特殊部位宫角妊娠的诊断和治疗。方法 对我院1991-2001年收治的宫角妊娠临床资料进行回顾性分析。结果 宫角妊娠17例中误诊宫内妊娠行人流失败4例。13例行腹部手术，3例行B超监视下人流术，1例行子宫动脉栓塞术。结论 宫角妊娠临床诊断困难，误诊率高，破裂后造成迅猛的腹腔内出血，应提高对少见部位宫角妊娠的认识，减少孕妇死亡。     

超声波提取快速测定复混肥料中的水溶性磷

研究超声波提取复混肥料中水溶性磷的方法及提取条件对测定结果的影响,该方法与国家标准GB150632001《复混肥料》中规定的方法比较,操作简单、省时,准确度较高,RSD值小于0.5%。     

Guidance of dopaminergic neuritic growth by immature astrocytes in organotypic cultures of rat fetal ventral mesencephalon.

Astrocytes, with their many functions in producing and controlling the environment in the brain, are of great interest when it comes to studying regeneration after injury and neurodegenerative diseases such as in grafting in Parkinson's disease. This study was performed to investigate astrocytic guidance of growth derived from dopaminergic neurons using organotypic cultures of rat fetal ventral mesencephalon. Primary cultures were studied at different time points starting from 3 days up to 28 days. Cultures were treated with either interleukin-1 beta (IL-1 beta), which has stimulating effects on astrocytic proliferation, or the astrocytic inhibitor cytosine arabinoside (Ara-C). Tyrosine hydroxylase (TH)-immunohistochemistry was used to visualize dopaminergic neurons, and antibodies against glial fibrillary acidic protein (GFAP) and S100 beta were used to label astrocytes. The results revealed that a robust TH-positive nerve fiber production was seen already at 3 days in vitro. These neurites had disappeared by 5 days. This early nerve fiber outgrowth was not guided by direct interactions with glial cells. Later, at 7 days in vitro, a second wave of TH-positive neuritic outgrowth was clearly observed. GFAP-positive astrocytic processes guided these neurites. TH-positive neurites arborized overlying S100 beta-positive astrocytes in an area distal to the GFAP-positive astrocytic processes. Treatment with IL-1 beta resulted in an increased area of TH-positive nerve fiber network. In cultures treated with Ara-C, neither astrocytes nor outgrowth of dopaminergic neurites were observed. In conclusion, this study shows that astrocytes play a major role in long-term dopaminergic outgrowth, both in axonal elongation and branching of neurites. The long-term nerve fiber growth is preceded by an early transient outgrowth of dopamine neurites.     

正常成人睾丸血流的彩色多普勒观察

为了探讨彩色多普勒血流显像技术显示正常人睾丸内血流的可行性，并探讨睾丸的血流动力学特征，我们对２０名正常人双侧睾丸进行了彩色多普勒检查。结果显示，彩色多普勒能显示所有睾丸的包膜动脉、向心动脉。正常睾丸的包膜动脉和向心动脉收缩期峰值血流速度的均值分别为９．００ｃｍ／ｓ和７．４２ｃｍ／ｓ；舒张末期血流速度均值分别为３．５０ｃｍ／ｓ和３．３８ｃｍ／３，本文对睾丸彩色血流显像和多普勒频谱特点也作了讨论。     

胆囊小隆起性病变的诊断及治疗

报告37例胆囊小隆起性病变，其中良性颈变34例，胆囊癌3例。结果：本组23例有临床症状，多表现为反复发作的右上腹疼痛或不适；病灶部位，大小，多少，有无合并胆石及病变性质与临床症状有关；B-us,OCG,CT的诊断符合率例如辚33／37，9／24和5／10（x^2=18.75,P<0.005)。认为对胆囊小隆起性病变的病灶≥10mm，有增大趋势，呈恶性图像，合并胆石或血清CEA升高的病例应及早手术治疗。     

老年主动脉瓣闭锁不全的彩色多普勒超声心动图研究

报告接受彩色多普勒超声心动图检查的老年患者162例，其中75例有不同程度的主要动脉瓣关闭不全（Ar)。老年（Ar)的病因构成与中，老年前期者明显不同，主动脉，瓣钙化及原因不明者的比例占多数（67％）。主动脉瓣钙化者Ar程度多较重。主动脉瓣钙化及原因不明Ar患者的其他三个瓣膜返流检出率及和程度均明显高于无Ar的老年患者。表明多瓣膜退行性病变是此类Ar患者的原因之一。     

冠心病患者颈动脉粥样硬化检测及意义

目的　探讨冠心病患者与颈动脉粥样硬化之间的发生关系。方法　主要应用彩色多普勒超声技术检测 10 2例冠心病患者的颈动脉 ,对其中 34例进行冠状动脉造影检查。结果　为各组冠心病患者颈动脉管壁内 -中膜厚度 ,斑块指数均显著增高 ,其中心肌梗死患者伴有明显的血流参数异常 ,34例患者冠状动脉造影与颈动脉超声检查符合率为 75 % ,而且冠状动脉病变越重 ,颈动脉硬化发生率越高。结论　颈动脉粥样硬化程度可间接反映冠状动脉病变程度。