大额牛,云南瘤牛横纹肌组织形态学研究

首次采用组织学、电镜方法对大额牛和云南瘤牛的横纹肌进行了观察，测量了两牛的肌纤维直径和肌节（含各带的长度）．结果表明，两种牛的横纹肌的肌纤维排列，以大额牛最为紧密，云南瘤牛公牛疏松，去势牛居中；肌纤维直径以云南瘤中公牛最粗，去势瘤牛居中，大额牛最细；肌节长度以大额牛最长（１．７０６５μｍ），去势瘤牛居中（１．４６７０μｍ），公瘤牛最短（１．２０５０μｍ）；肌丝配布为中央一条粗肌丝转以六条细肌丝．综合大额牛横纹肌的组织结构特点，表明其肉质优于云南瘤牛．     

快速力量训练及减训对大鼠骨骼肌微细结构的影响

研究了快速力量训练及减量训练对大鼠骨骼肌微细结构的影响.结论:减量训练会导致骨骼肌内糖原的减少和线粒体的增多,而且强度减得越多,这种变化越明显.     

The effects of thermogenic agents on hindlimb oxygen consumption in the dog: ICI D7114 and noradrenaline

The thermogenic action of beta-adrenoceptor agonists may be due, in part, to increased metabolism in skeletal muscle. Previous results suggest that vasoconstriction is also necessary, and that the effect can be blocked by vasodilators. Both noradrenaline and the beta-3 agonist, ICI D7114, were studied using two dog hindlimb protocols. During constant perfusion conditions, ICI D7114 caused a significant increase in hindlimb oxygen consumption although it is a vasodilator. Noradrenaline resulted in a smaller rise in oxygen consumption, and produced a marked vasoconstriction. Both noradrenaline and ICI D7114 resulted in decreased oxygen consumption when the blood flow was allowed to vary in response to the drug treatment. The results suggest that changes in tissue oxygen consumption caused by beta-agonists are not related to vasomotion.     

AMPK-α表达变化在糖尿病患者骨骼肌脂肪酸代谢和胰岛素抵抗中的作用

目的探讨腺苷酸活化蛋白激酶α(AMPK-α)表达变化在糖尿病患者骨骼肌脂肪酸代谢和胰岛素抵抗中的作用.方法在骨科行髋关节和下肢手术的患者中选取Ⅱ型糖尿病病程≤5 a的患者20例为研究组,另选取行骨科手术的非糖尿病患者20例为对照组.抽取空腹静脉血检测血生化指标;骨科术中留取骨骼肌组织,测定骨骼肌TG、长链脂酰辅酶A(LCACo A)水平;RT-PCR法检测骨骼肌AMPK-α1,AMPK-α2 mRNA水平;Western blotting法检测骨骼肌AMPK-α1,AMPK-α2和磷酸化AMPK-α蛋白水平.结果研究组空腹血糖、糖化血红蛋白、胰岛素、TG、FFA水平均明显高于对照组,ISI明显低于对照组,差异具有统计学意义(P0.05);研究组骨骼肌TG,LCACo A含量均明显高于对照组,差异具有统计学意义(P0.05).研究组和对照组AMPK-α1 mRNA拷贝数之间差异无统计学意义(P0.05);研究组AMPK-α1 mRNA拷贝数明显低于对照组,差异具有统计学意义(P0.05).研究组和对照组AMPK-α1蛋白表达量之间差异无统计学意义(P0.05);研究组AMPK-α2和磷酸化AMPK-α蛋白水平明显低于对照组,差异具有统计学意义(P0.05).结论Ⅱ型糖尿病患者易发生脂肪酸代谢异常和胰岛素抵抗,AMPK-α2表达和AMPK-α活性改变在骨骼肌脂质堆积和胰岛素抵抗中发挥关键作用.     

Calcium-induced calcium release mechanism in vascular smooth muscles — assessments based on contractions evoked in intact and saponin-treated skinned muscles

Summary This article was concerned with the role of Ca in triggering the contraction in vascular smooth muscles. Whenever Ca influx is activated, this Ca does not directly activate the contractile proteins, but rather triggers the release of Ca from the SR to activate calmodulin. This release of Ca by Ca is dependent on the amount of Ca stored within the cells.Voltage dependent Ca influx activated by excess concentrations of K, electrical depolarization and Ca spikes is required to produce the contraction through activation of the Ca-induced Ca release mechanism. The elucidation of the contribution of the P-I response for Ca mobilization through activation of receptors under physiological conditions hopefully will lend support to our hypothesis.     

红罗非鱼的骨骼系统

采用3种方法制成红罗非鱼整体和分离的骨骼标本,并详细叙述了骨骼系统的结构.红罗非鱼鼻骨发达,无后耳骨和基蝶骨,眶后骨短管状,脑颅背面有由额骨、颅顶骨和上枕骨共同形成的3列骨嵴以及第三椎体上有强大腹突等是红罗非鱼骨骼系统的主要特点.     

乌鳢骨骼系统的解剖

乌鳢是一种适应性很强的经济鱼类，具有副呼吸器官，可直接利用空气中的氧气，该鱼同时具有背肋及腹肋，颌弓与脑颅为硬骨鱼中少有的双联型，脑颅的桅民具眶蝶骨，此点和Ｄａｙ（１９１４）的结论不同，故此种鱼的骨骼系统具有重要的比较解剖学方面的价值。     

Expression of alpha-cardiac myosin heavy chain in mammalian skeletal muscle

We have investigated the reactivity of different human, rat and cat muscles to a monoclonal antibody directed against human -cardiac myosin heavy chain. We have found that special fiber subpopulations of human massetr and extraocular muscles, as well as the bag fibers of human, rat and cat muscle spindles, were reactive to this antibody, indicating that these fibers expressed -cardiac myosin heavy chain or a closely related isoform. This isomyosin was present in the spindle bag fibers at early fetal stages, whereas its expression in masseter and extraocular muscle fibers was not detected during the first 22 weeks of gestation. Our results add to the list of muscle proteins which are expressed in locations or at developmental stages other than those initially described, suggesting that a revision of the present nomenclature of the subgroups of myosin heavy chains might be considered in the future.     

Decreased rates of Ca2+-dependent heat production in slow- and fast-twitch muscles from the dystrophic (mdx) mouse

Using a newly developed microcalorimetric approach to assess the rate of energy expenditure for intracellular [Ca²⁺] homeostasis in isolated muscles at rest, we found this was lower inmdx than in control mouse muscles, by 62% and 29% in soleus and extensor digitorum longus, respectively. Differences in total and Ca²⁺-dependent rates of specific heat production betweenmdx and control were enhanced during sustained, KCl-induced stimulation of energy dissipation. These results suggest that the low sacroplasmic energy status of dystrophic muscles is not due to any excessive energy expenditure for intracellular [Ca²⁺] homeostasis.     

洋葱液对离体蛙心心肌收缩力的影响

目的：探讨洋葱液对离体蛙心心肌收缩力的影响。方法：采用改进的斯氏蛙心插管法，在保持总剂量为1．0ml的情况下，分别以不同剂量的洋葱液对离体蛙心脏进行灌流，经张力换能器、BL-410智能生物信号显示与处理系统记录心肌的收缩活动。结果：灌流同一浓度不同剂量的洋葱液时，小剂量的洋葱液(0．2m1)使心肌收缩迅速加强，达到一定程度再缓慢减弱。而大剂量的洋葱液(0．4、0．6、0．8、1．0ml)使心肌收缩迅速受到抑制，剂量越大抑制越强烈，对心率影响不明显。结论：小剂量的洋葱液使心肌收缩加强，而大剂量的洋葱液使心肌收缩减弱，心率变化不大。