Dynamic relationship between EMG and torque at the human ankle: Variation with contraction level and modulation

Stochastic system identification techniques were used to determine the dynamic relationship between the electromyogram (EMG) and torque in the ankle muscles of normal human subjects. EMG and torque were recorded while subjects modulated ankle torque by tracking a computer-generated stochastic waveform. Nonparametric impulse response functions (IRFs) relating EMG to ankle torque were computed and parameterised by determining the parameters of the second-order system which provided the best least-squares fit. Two sets of experiments were carried out. In the first, the mean level of torque was varied from 5 per cent of the maximum voluntary contraction (MVC) to 30 per cent MVC while the depth of modulation was held constant at ±5 per cent of MVC. In the second series of experiments the mean torque was held constant at 25 per cent MVC while the depth of modulation was varied from ±2.5 per cent to ±25 per cent. The major findings were: (1) A second-order, low-pass filter provided a good quasilinear model of the EMG/force dynamics under all conditions; (2) The model parameters depended only weakly on the mean level of torque; (3) In contrast, the model parameters depended strongly on the amplitude with which the contraction was modulated; the natural frequency increased significantly with the depth of modulation.     

人血清载脂蛋白H的纯化与鉴定

为了研究载脂蛋白H（apoH)与疾病的关系，分别用HClO4,(NH4)2SO4沉淀、DEAE－纤维素离子交换层析，从人血清中纯化了载脂蛋白Ho用测定分子量，分析氨基酸组成和N－端氨基酸测序三个方面进行鉴定。用SDS－PAGE测得其相对分子量对54000。用高效液相色谱测定其中15种氨基酸的相对含量（mol/10^3mol残基）如下：Asp119.8,Glu108,Thr94.8,Ser78.6,Phe64.9,Gly1008,Ala57.2,Val57.2,Met10.6,Ile50.3,Leu77.1,Tyr31.9,His15.2,L-ys81.4,Arg39.4;d PE-ABI公司生产的475A型气相蛋白质测序仪上测得其N端10个氨基酸残基顺序如下：NH2－Gly-Arg-Cys-Pro-Asp-Asp-Leu。纯化得到的apoH与肝素有高的亲和性，还能与乙肝表面抗原结合。纯化apoH的方法相对比较简单，能达到测序的要求。     

后路腰椎间盘镜治疗多节段腰椎间盘突出症

目的探讨多节段腰椎间盘突出症的后路腰椎间盘镜(MED)手术治疗方法。方法回顾性分析2000年至2004年经MED治疗的45例多节段椎间盘突出症的临床资料。结果对45例患者共93个椎间盘进行了手术，平均住院时间14．8d，平均手术时间92min，平均手术出血量145ml，术后随访3个月至40个月，手术优良率为91．6％。结论多节段腰椎间盘突出症是MED手术治疗的相对适应证，相对于单节段的MED手术，术前定位和术中操作更困难，严格的病例选择和全面的术前分析，辅以熟练的手术操作，仍可获得较为满意的疗效。     

A PCR–restriction fragment length polymorphism assay to genotype human metapneumovirus

Human metapneumovirus (hMPV) genotypes A and B show epidemiological and probably clinical differences. This report describes a fast and simple PCR–restriction fragment length polymorphism (PCR-RFLP) assay, involving digestion of the fusion protein gene with Tsp 509I, that allows lineages A1, A2, B1 and B2 to be distinguished. The assay should help in elucidating the epidemiology of hMPV, and possibly in predicting the severity of clinical infection.     

Natural antimicrobial susceptibility patterns and biochemical profiles of Leclercia adecarboxylata strains

Leclercia adecarboxylata is an opportunistic human pathogen that phenotypically resembles Escherichia coli. The natural susceptibilities of 101 Leclercia strains to 70 antimicrobial agents were investigated. MICs were determined with a microdilution procedure in cation-adjusted Mueller-Hinton broth (all strains) and IsoSensitest broth (some strains). Natural susceptibility patterns were assessed using German (DIN) standards (when applicable). In addition, biochemical properties recommended for the phenotypic identification of L. adecarboxylata were evaluated, applying two commercially available identification systems for Enterobacteriaceae and seven conventional tests. L. adecarboxylata strains were naturally sensitive to tetracyclines, aminoglycosides, all but two beta-lactams, quinolones, folate pathway inhibitors, chloramphenicol, nitrofurantoin and azithromycin. They were naturally resistant to penicillin G, oxacillin, erythromycin, roxithromycin, clarithromycin, ketolides, lincosamides, streptogramins, linezolid, glycopeptides, rifampicin, fusidic acid and fosfomycin. There were only minor medium-dependent differences in susceptibility to most antibiotics. Lysine decarboxylase, malonate assimilation and acid production from arabitol and cellobiose, but not from adonitol and sorbitol, allowed definitive separation of L. adecarboxylata from E. coli. The results of this study form a database that can be applied to validate forthcoming antibiotic susceptibility tests of L. adecarboxylata, and might contribute to its reliable identification. Susceptibility patterns did not indicate obvious therapeutic difficulties for treatment of Leclercia infections. Special attention should be paid to biochemically aberrant leclerciae. Apart from biochemical features, fosfomycin susceptibility might be useful to differentiate between L. adecarboxylata and E. coli.     

延髓后角脑啡肽超微结构定位和非突触部位释放——脑啡肽突触前抑制痛觉传递的形态学基础

阿片肽在后角镇痛的作用机理,被认为是通过突触前抑制一级传入纤维P物质释放的结果,然而始终未获得形态学的证实。鉴于一级传入纤维存在大量阿片受体的事实,曾提出阿片肽突触前抑制可能是通过非突触的轴-轴作用。为了验证这一设想,本文用免疫组化方法,详细观察了大鼠延髓后角浅层亮氨酸脑啡肽(L-ENK)轴突终末的突触结构和胞吐释放。电镜观察显示,延髓后角ENK终末可分为两类,第一类终末除了含圆形小清亮囊泡外,还有较多的大颗粒小泡(一般7个以上),主要分布于Ⅰ层,很少看到此类终末形成突触;第二类终末,一般含较多圆形清亮小泡和少量大颗粒小泡(一般不超过3个),它们分布于Ⅰ层和Ⅱ层,此类终末主要形成轴-树突触和少量的轴-体突触。只见到一例轴-轴突触,其突触后成分为未标记的R型终末,此外还见到ENK阳性树突成为中央终末的突触后成分。在去传入神经条件下,上述各类终末皆可见到ENK阳性大颗粒小泡的胞吐形成,它们皆位于非突触区,而在突触部位可见到清亮小泡胞吐像,上述结果提示后角ENK非突触部位释放可能是哭触后抑制一级传入纤维P物质释放的形态学基础。     

Identification of an obeche (Triplochiton scleroxylon) wood allergen as a class I chitinase

BACKGROUND: Wood dust is known to cause allergic occupational asthma and obeche (Triplochiton scleroxylon) is a prominent exponent in this field. However, the knowledge about wood allergens is still limited. The aim of this study was to identify and characterize obeche wood allergens. METHODS: Obeche extracts were prepared from freshly ground in comparison to 7 years stored wood dust and investigated by Sodium dodecyl sulfate-polyacrylamid gel electrophoresis, enzyme-linked allergosorbent test and immunoglobulin (Ig)E-immunoblot. Allergens were detected by specific IgE of seven obeche allergic patients' sera and protein analysis was performed by mass spectrometry. Cross-reactivity was demonstrated by ImmunoCAP-inhibition with sera of seven obeche and four latex-allergic patients. RESULTS: Obeche extracts showed different protein pattern and IgE-binding capacities depend on the age of the wood dust. A 38 kDa protein was identified as major obeche wood allergen, detected by six of seven (85%) obeche allergic patients' sera and was entitled as Trip s 1. Trip s 1 is homologous to plant class I chitinases and exhibited enzyme activity demonstrated by chitinolysis. Co-recognition or cross-reactivity of Trip s 1 according to structural similarity was seen in sera of latex allergic patients. IgE inhibition studies with obeche as solid phase and Trip s 1 and latex hevein as inhibitor demonstrated that Trip s 1 was a more effective inhibitor in obeche as well as in latex allergic patients' sera. CONCLUSIONS: Trip s 1 is a new obeche wood allergen of the plant class I chitinase family. This finding may explain the dominant role of obeche in sensitization against wood dust.     

A String Matching Computer-Assisted System for Dolphin Photoidentification

This paper presents a syntactic/semantic string representation scheme as well as a string matching method as part of a computer-assisted system to identify dolphins from photographs of their dorsal fins. A low-level string representation is constructed from the curvature function of a dolphin's fin trailing edge, consisting of positive and negative curvature primitives. A high-level string representation is then built over the low-level string via merging appropriate groupings of primitives in order to have a less sensitive representation to curvature fluctuations or noise. A family of syntactic/semantic distance measures between two strings is introduced. A composite distance measure is then defined and used as a dissimilarity measure for database search, highlighting both the syntax (structure or sequence) and semantic (attribute or feature) differences. The syntax consists of an ordered sequence of significant protrusions and intrusions on the edge, while the semantics consist of seven attributes extracted from the edge and its curvature function. The matching results are reported for a database of 624 images corresponding to 164 individual dolphins. The identification results indicate that the developed string matching method performs better than the previous matching methods including dorsal ratio, curvature, and curve matching. The developed computer-assisted system can help marine mammalogists in their identification of dolphins, since it allows them to examine only a handful of candidate images instead of the currently used manual searching of the entire database. © 2000 Biomedical Engineering Society. PAC00: 8780Tq, 4230Sy, 0705Pj     

人嗜铬细胞瘤细胞的原代培养及鉴定

本研究拟建立人嗜铬细胞瘤细胞的原代培养方法。采用连续分次胶原酶消化法分离培养人嗜铬细胞瘤细胞，采用细胞培养液中儿茶酚胺水平检测、多聚甲醛诱发荧光及细胞嗜铬粒蛋白A(CgA)和神经元特异性烯醇化酶(NSE)的免疫组化染色等方法进行细胞性质和功能鉴定，并用噻唑兰(MTT)法观察原代培养的人嗜铬细胞瘤细胞的生长状况。结果表明，人嗜铬细胞瘤细胞在培养3～7天时生长较快，7天后细胞开始分化。经检测细胞培养液中的儿茶酚胺浓度、多聚甲醛诱发荧光等，证明该细胞有合成和分泌儿茶酚胺的功能。并且培养的细胞CgA和NSE免疫组化染色阳性。因此，本研究成功建立了人嗜铬细胞瘤细胞的原代培养方法，并鉴定其具有嗜铬细胞瘤的分泌和表达功能，国内尚未见报告。