大鼠骨骼肌快肌肌钙蛋白T的同工型

骨骼肌快肌的收缩主要是由钙离子通过肌钙蛋白所调节控制。这些肌钙蛋白位于肌纤维之中。肌蛋白包括肌钙蛋白T、肌钙蛋白C、肌钙蛋白I。采用双向聚丙烯酰胺凝胶电泳和免疫学技术,对大鼠胚胎、新生大鼠和成年大鼠的骨能肌快肌肌钙蛋白T的同工型进行了研究。在成年大鼠的骨能肌快肌中,发现了10种肌钙蛋白T同工型。在大鼠胚胎和新生大鼠的骨能肌中,发现了7种肌钙蛋白T同工型。作为不同动物、不同发育阶段和不同组织发育的特殊标记,这些肌钙蛋白T同工型具有重要意义[动物学报49(3)：362—369,2003]。     

不同负荷方式引起的腰部肌肉表面肌电信号变化特征

采用时频、复杂度和定量递归信号分析方法对Biering-sorensen和Ito-Shirado条件下腰部肌肉表面肌电信号的变化规律和特点进行了比较。10名正常受试者分别参加Biering-sorensen和Ito-Shirado运动负荷试验,分别获取两侧L2～L3和L5～S1部位表面肌电信号。研究发现,以上两种运动负荷方式下平均功率频率和复杂度时间序列曲线呈单调递减型变化,而确定性线段百分数时间序列曲线呈单调递增型变化。双因素方差分析表明负荷方式和采样部位对以上信号分析指标变化斜率的影响均有显著统计学意义,证明Biering-sorensen负荷方式较Ito-Shirado负荷方式对腰部肌肉表面肌电信号特征有较大的影响,而采样部位也是腰部肌肉功能评价不可忽视的因素。     

表面肌电信号的下肢痉挛信号的特征分析与识别

脑卒中患者康复治疗中会引起下肢肌肉痉挛,这种现象给患者的康复训练过程带来极大的危害,因此能够在训练过程中识别痉挛并及时中断训练具有重要的实际意义。本研究通对下肢表面肌电信号的采集,采用基于形状的模版匹配法来识别痉挛信号,并以皮尔逊相关系数来分析表征下肢痉挛信号的相关性大小。分析结果表明,通过仿真验证了模版匹配法在个人痉挛信号识别中的准确性,显示了在泛用痉挛信号识别中的可行性。     

功能性电刺激对痉挛型双瘫型脑瘫患儿下肢运动功能的影响

目的:探讨功能性电刺激(FES)对痉挛型双瘫型脑瘫患儿下肢运动功能的影响。方法:将2012年7月-2014年6月我院儿科康复中心141例痉挛型双瘫脑瘫患儿随机分为观察组(73例)与对照组(68例),对照组采用常规综合康复治疗,观察组在此基础上再给予FES治疗,持续治疗12周,在治疗前及治疗后12周后测定MAS评分、踝关节背屈活动度(ROM)评分以及粗大运动功能测试量表(GMFM)评分。结果:经治疗12周后,两组ROM评分和GMFM评分均显著高于治疗前(P0.05),且观察组上升更明显(P0.05);两组MAS评分均显著低于治疗前(P0.05),且观察组降低更明显(P0.05)。结论:FES结合运动训练可显著缓解下肢肌群痉挛程度,改善踝关节运动范围和功能,促进下肢运动功能的恢复,值得临床推广。     

不同雌激素水平下大鼠颏舌肌肌电反应的研究

目的：通过比较不同雌激素水平下大鼠颏舌肌的肌电反应,探讨雌激素在预防及降低阻塞性睡眠呼吸暂停低通气综合征（OSAHS）发病过程中的作用机制。方法：选择30只6周龄SD大鼠建立不同雌激素水平模型,用电子称评估术前、术后和雌激素替代治疗后大鼠的体重变化;放射免疫法检测血清雌激素水平;电生理方法检测不同雌激素水平颏舌肌的肌电反应。结果：与假手术组（SHAM）相比,去势组（OVX）大鼠术后6周体重明显增加（P〈0．01）,雌激素替代治疗组（OVX＋E2）与SHAM组体重相当。血清雌激素检测结果显示OVX组雌激素水平最低,与SHAM组相比具有显著差异（P〈0．01）;OVX＋E2组雌激素水平高于OVX组（P〈0．01）,但仍未恢复到SHAM组水平。电生理检测结果显示,与SHAM组相比,OVX组颏舌肌肌电强度最低（P〈0．05）,OVX＋E2组颏舌肌的肌电强度显著高于OVX组（P〈0．05）,但仍低于SHAM组。结论：血清雌激素水平可以直接影响大鼠颏舌肌肌电强度．这可能是雌激素保护OSAHS的原因之一。     

基于表面肌电的不同脊柱前后倾角坐姿腰部肌肉收缩情况研究

摘要 目的：本研究通过飞行座椅模拟飞行员坐姿状态,利用表面肌电技术对不同脊柱前后倾角坐姿的腰部肌肉收缩情况进行评价,为飞行员的坐姿提供一定的参考。方法：本研究共招募20名被试者,每名被试者先后参加三组实验。在实验过程中,被试者坐于飞行座椅中并保持躯体中立正直状态,通过调节脚踏板位置使脊柱前后倾角分别固定为90 °、100 °和110 °,要求被试者尽全力使全身肌肉收缩15 s,同时记录双侧多裂肌和竖脊肌的肌电信号,为避免发生肌肉疲劳,每组间隔1分钟。结果：四块所测肌肉在100 °脊柱前后倾角下的均方根值（RMS）和积分肌电值（IEMG）均大于90 °（P＜0.01）;右侧多裂肌在110 °脊柱倾角下的RMS值大于90 °（P＜0.05）;左侧多裂肌和左右竖脊肌在100 °脊柱前后倾角下的RMS值大于110 °（P＜0.05）,右侧竖脊肌在100 °脊柱前后倾角下的IEMG值大于110 °（P＜0.01）;在每组肌肉中,其余脊柱前后倾角之间肌电信号的比较没有统计学意义（P＞0.05）。结论：在不同的脊柱前后倾角中,左右多裂肌和竖脊肌在脊柱前后倾角为100 °的坐姿中能发挥更大的肌肉力量。     

慢性非特异性颈部不适飞行员与无症状飞行员之间头颈夹肌表面肌电特征的比较

目的:通过对慢性非特异性颈部不适飞行员与无症状飞行员之间头颈夹肌表面肌电特征的比较,为慢性非特异性颈部不适飞行员的早期诊断提供参考依据。方法:用表面肌电仪测量52名慢性非特异性颈部不适飞行员与11名无症状飞行员双侧头颈夹肌的松弛状态、等长收缩以及异长收缩时的表面肌电特征,分析不同状态下双侧头颈夹肌疲劳性肌电指标MFs、MPFs、ZCRs以及平均肌电AEMG值,用统计学软件SPSS 18.0分析实验结果。结果:非特异性颈部不适飞行员与无症状飞行员双侧头颈夹肌在松弛状态时疲劳性肌电指标MFs、MPFs、ZCRs比较均无统计学差异(P0.05),其双侧头颈夹肌在等长收缩和异长收缩时间有统计学差异(P0.05)。头颈夹肌处于松弛状态时,两组间平均肌电AEMG比较无统计学差异(P0.05),而在肌肉等长收缩和异长收缩时,两组间比较有统计学差异(P0.05)。结论:慢性非特异性颈部不适飞行员与无症状飞行员之间头颈夹肌表面肌电相关指标存在统计学差异,慢性颈部不适的飞行员相比无症状飞行员更易出现头颈夹肌的疲劳以及头颈夹肌的功能下降。头颈夹肌表面肌电特征有助于早期诊断慢性非特异性颈部不适飞行员的肌肉功能状态的改变。     

大鼠单一肌梭的电生理特征

本研究旨在观察大鼠单一肌梭的电生理特征.从大鼠比目鱼肌中分离单一肌梭,用空气隔绝法观察大鼠单一肌梭感觉末梢在不同液体环境中的放电活动.结果显示:在基础生理盐水溶液中,大鼠单一肌梭的自发放电频率很低,平均(51.78±25.63) impulse/1000s(n=13);在加有适量氨基酸的生理盐水溶液中,其自发放电频率明...     

血糖浓度变化与消化间期综合肌电周期的关系

在狗的十二指肠浆膜面埋植银-氯化银双极电极,记录空腹时的肌电活动,观察血糖浓度变化与消化间期综合肌电(IDMEC)周期的关系。实验结果表明:(1)血糖浓度随 IDMEC周期的不同时相而变动,Ⅰ相最高,Ⅱ相次之,Ⅲ相最低(P<0.01)。(2)静脉注射酚妥拉明或心得安后。血糖浓度随 IDMEC 周期的波动均消失。(3)切除双侧迷走神经干后,血糖浓度略有升高,随 IDMEC 的周期性波动依然存在。(4)分别阻断肾上腺素α、β受体及切除迷走神经后,不影响 IDMEC 的周期性活动,但可使周期延长,各相所占时程百分比发生变化。以上结果证明,空腹情况下血糖浓度随 IDMEC 周期的不同时相而变动,交感神经和迷走神经具有一定的调节作用。     

局部肌肉疲劳的表面肌电信号复杂度和熵变化

目的 在于探讨静态和动态疲劳性运动过程中肱二头肌和腰部脊竖肌表面肌电(surface electromyography,sEMG)信号的Lempel-Ziv复杂度和Kolmogorov熵的变化规律。18名男性大学生志愿者被随机分为肱二头肌和腰部脊竖肌运动负荷组,分别完成静态和动态疲劳运动负荷试验。运动负荷期间连续记录sEMG信号,在对运动负荷时间和重复次数进行标准化处理后,截取相应时段的sEMG信号,计算Lempel-Ziv复杂度和Kolmogorov熵,观察它们随肌肉疲劳发展的变化规律。研究结果表明,无论是静态还是动态疲劳运动条件下,被检肌肉sEMG信号的复杂度和熵均随着运动负荷时间呈现明显的单调递减型变化。该变化可能与神经系统渐进性协调众多运动单位同步收缩的‘协同效应”有关。     

肌肉收缩Hill特性式的理论研究

从肌球蛋白工作循环的机械化学偶联模型出发,利用化学动力学方法和生物化学热力学原理,结合肌球蛋白单分子实验结果,从能量转化的观点给出了肌肉收缩的Hill特性式,加深了对Hill特性式及肌肉收缩过程中能量转化的理解,在整合肌球蛋白单分子性质与肌肉收缩宏观性质的信息方面做了尝试。     

痉挛性肌张力增高的神经外科治疗

目的:分析总结在周围神经肌电监测指导下行缩窄神经术降低痉挛性高肌张力,改善关节强直的临床疗效。方法:对16例关节强直患者术中在周围神经肌电监测指导下,在显微镜下行神经缩窄术,其中脑性瘫痪患者9例,脑炎后遗症患者2例,中毒性脑病1例,脑外伤后遗症患者1例,颈髓损伤患者1例,脑积水患者1例,烟雾病伴脑梗死患者1例。用表面肌电(surface electro myo graphy,s EMG)及改良的Ashworth(Modified A shworth Scale,MAS)肌张力分级标准对强直肢体肌张力评定。结果:所有患者的痉挛肢体肌张力明显下降,症状显著改善。肌电信号均方根值术前与术后比较,采用配对样本的T检验分析,P值0.001,差异有统计学意义。术后感觉障碍发生率为12.5%(2/16),术后肌力明显减低发生率为18.8%(3/16),随访期间完全恢复。结论:术中在周围神经肌电监测指导下,显微镜下行神经缩窄术治疗痉挛性关节强直是有效的外科治疗方法,效果确切。     

The Intracellular Site of Calcium Activation of Contraction in Frog Skeletal Muscle

Radioautography has been used to localize ⁴⁵Ca in isotopically labeled frog skeletal muscle fibers which had been quickly frozen during a maintained tetanus, a declining tetanus, or during the period immediately following a tetanus or a contracture. During a tetanus almost all of the myofibrillar ⁴⁵Ca is localized in the region of the sarcomere occupied by the thin filaments. The amount varies with the tension being developed by the muscle. The movement of calcium within the reticulum from the tubular portion to the terminal cisternae during the posttetanic period has a half-time of about 9 sec at room temperature and a Q₁₀ of about 1.7. Repolarization is not necessary for this movement. Evidence is given to support the notion that most calcium efflux from the cell occurs from the terminal cisternae into the transverse tubules.     

Developmental Appearance of Sodium Channel Subtypes in Rat Skeletal Muscle Cultures

22Na influx was measured in the established muscle cell line L-6 and in primary rat skeletal muscle cultures following activation of sodium channels by veratridine and sea anemone toxin II. Inhibition of the activated channels by tetrodotoxin (TTX) was analyzed with computer-assisted fits to one- or two-site binding models. In L-6 cultures, two inhibitable sodium channel populations were resolved at all ages in culture: a TTX-sensitive (K = 0.6-5.0 X 10(-8) M) and an insensitive population (Ki = 3.3-4.9 X 10(-6) M). In primary rat muscle cultures, the sensitivity of the toxin-stimulated channels to TTX changed with time in culture. In 4-day-old cultures, a single sodium channel population was detected using TTX (Ki = 2.4 X 10(-7)M). A single population was also found in 6-day-old cultures (Ki = 5.3 X 10(-7) M). By day 7 in culture, the inhibition of 22Na influx by TTX could be resolved into two components with high- and low-affinity sites for the toxin (Ki = 1.3 X 10(-9) M and 9.6 X 10(-7) M). We conclude that a single, toxin-activated sodium channel population with low affinity for TTX exists at early stages, whereas a second, high-affinity population evolves with time in primary rat muscle cultures. The expression of a high-affinity site apparently does not require ongoing neuronal involvement and may reflect an intrinsic property of the muscle cells.     

Local Control Model of Excitation–Contraction Coupling in Skeletal Muscle

The voltage-activated H⁺ selective conductance of rat alveolar epithelial cells was studied using whole-cell and excised-patch voltage-clamp techniques. The effects of substituting deuterium oxide, D₂O, for water, H₂O, on both the conductance and the pH dependence of gating were explored. D⁺ was able to permeate proton channels, but with a conductance only about 50% that of H⁺. The conductance in D₂O was reduced more than could be accounted for by bulk solvent isotope effects (i.e., the lower mobility of D⁺ than H⁺), suggesting that D⁺ interacts specifically with the channel during permeation. Evidently the H⁺ or D⁺ current is not diffusion limited, and the H⁺ channel does not behave like a water-filled pore. This result indirectly strengthens the hypothesis that H⁺ (or D⁺) and not OH⁻ is the ionic species carrying current. The voltage dependence of H⁺ channel gating characteristically is sensitive to pH_o and pH_i and was regulated by pD_o and pD_i in an analogous manner, shifting 40 mV/U change in the pD gradient. The time constant of H⁺ current activation was about three times slower (τ_act was larger) in D₂O than in H₂O. The size of the isotope effect is consistent with deuterium isotope effects for proton abstraction reactions, suggesting that H⁺ channel activation requires deprotonation of the channel. In contrast, deactivation (τ_tail) was slowed only by a factor ≤1.5 in D₂O. The results are interpreted within the context of a model for the regulation of H⁺ channel gating by mutually exclusive protonation at internal and external sites (Cherny, V.V., V.S. Markin, and T.E. DeCoursey. 1995. J. Gen. Physiol. 105:861–896). Most of the kinetic effects of D₂O can be explained if the pK _a of the external regulatory site is ∼0.5 pH U higher in D₂O.     

Interactions of ELF Magnetic Fields with Mouse Skeletal Muscle

The second generation of female OF1 mice exposed chronically to a magnetic field of 50 Hz and 15 μT (rms) was studied to find out the possible alterations in the skeletal muscle caused by this exposure. Animals were sacrificed at the age of 14 weeks, and their skeletal muscle studied by spectrophotometric and histopathological techniques. Calcium concentration was found to be significantly decreased in the experimental animals, while H₂O content, Na, K, Fe, Ni, Mg, and Zn concentrations were not significantly different from those of control animals. Histologically, we found variation in fiber size, rounded and widely separated fibers, centrally located nuclei, and intermyofibrillar lipids. We could not find necrosis, inflammatory infiltrate, or loss of either the filaments or the cross-striation.