臀肌重建术的解剖学和生物力学优化分析

在六侧新鲜儿童标本上,对臀肌重建术进行了应用解剖学和生物力学优化分析,比较了骶棘肌、腰大肌、背阔肌和腹外斜肌重建臀肌的效果,得到了移位肌的最优移置部位和移位后重建臀肌功能的估算。结果表明骶棘肌重建臀肌的效果最好,以下依次是腰大肌、背阔肌和胸外斜肌。     

圆斑蝰蛇毒中性磷脂酶A2对不同种类血管条作用的比较

本文比较了福建圆斑蝰蛇毒中性磷脂酶Ａ２（ＰＬＡ２－３）对人胃网膜动脉条、兔和大鼠主动脉条的作用，表面ＰＬＡ２－３对处于静息状态和预收缩状态的人网膜动脉能诱发松弛反应，而对大鼠和兔主动脉诱发剂量依赖性收缩反应，表明该ＰＬＡ２的血管作用具有血管种类差异性。ＰＬＡ２－３对大鼠主动脉的收缩反应是内皮细胞非依赖性的，去除内皮细胞能增强ＰＬＡ２－３所诱发的收缩反应；ＰＬＡ２－３所诱发的大鼠主动脉条收缩反应可能     

Force deficits after stretches of activated rat muscle-tendon complex with reduced collagen cross-linking

The forces produced during stretches of passive and activated muscles, and isometric force deficits after stretching of activated muscles were examined in rat plantor flexor muscle-tendon complexes with reduced collagen cross-links (pyridinoline). Female Sprague-Dawley rats (n=6, age 87 days) were injected twice daily for 43 days with β-aminopropionitrile (BAPN, 333 mg/kg/day i.p.), an inhibitor of lysyl oxidase, which is responsible for the production of collagen cross-links. The relative weights of the plantar flexor muscles were similar for BAPN and saline-injected (control, C) rats (n=6). Pyridinoline was lower in the tendon (22.9%), and in the plantaris (17.1%), and soleus (7.4%) muscles (P<0.05), with no changes observed in collagen content (hydroxyproline), as determined by high-pressure liquid chromatography. At an ankle position of 90°, groups had similar forces at 5, 10, 20, 40, 60 and 80 Hz before stretching. Forces at 40° with stretches of the passive muscles (five times from 90° to 40°) were lower for all stretches in BAPN-injected rats (P<0.05). Isometric force deficits resulting from stretches of activated muscles (80 Hz, 20 times from 90° to 40°, rest intervals 3 min) followed similar courses for BAPN-injected and C rats, and were 51.1 (2.4)% (C) and 54.7 (4.6)% (BAPN) before the last stretch. After 1 h of rest, isometric force deficits were 26% and 29% larger at 10 Hz and 5 Hz, respectively, in BAPN-treated rats (P<0.05). The reduction in BAPN-injected collagen cross-linking of the skeletal muscle-tendon complex reduced the forces produced during stretches without muscle stimulation (i.e. passive stretch), and stretching of activated muscles produced larger isometric force deficits only at low stimulation frequencies. Electronic Publication     

Effect of gaze direction on neck muscle activity during cervical rotation

Control of the neck muscles is coordinated with the sensory organs of vision, hearing and balance. For instance, activity of splenius capitis (SC) is modified with gaze shift. This interaction between eye movement and neck muscle activity is likely to influence the control of neck movement. The aim of this study was to investigate the effect of eye position on neck muscle activity during cervical rotation. In eleven subjects we recorded electromyographic activity (EMG) of muscles that rotate the neck to the right [right obliquus capitis inferior (OI), multifides (MF), and SC, and left sternocleidomastoid (SCM)] with intramuscular or surface electrodes. In sitting, subjects rotated the neck in each direction to specific points in range that were held statically with gaze either fixed to a guide (at three different positions) that moved with the head to maintain a constant intra-orbit eye position or to a panel in front of the subject. Although right SC and left SCM EMG increased with rotation to the right, contrary to anatomical texts, OI EMG increased with both directions and MF EMG did not change from the activity recorded at rest. During neck rotation SCM and MF EMG was less when the eyes were maintained with a constant intra-orbit position that was opposite to the direction of rotation compared to trials in which the eyes were maintained in the same direction as the head movement. The inter-relationship between eye position and neck muscle activity may affect the control of neck posture and movement.     

Maximal dynamic expiratory pressures with fast and slow inspirations

Maximal dynamic expiratory pressures are higher when forced expiration is preceded by a fast inspiration to total lung capacity (TLC) than when preceded by a slow inspiration and a few seconds pause at TLC. We hypothesized that these pressure differences are due to the stretch-shorten cycle (SSC), which refers to enhancement of muscle force when a concentric muscle contraction is immediately preceded by an eccentric contraction. Seven volunteers [36 (2) years; mean (SEM)] performed maximal forced expirations against minimal resistance with fast (F) or slow (S) maneuvers. F maneuvers consisted of a fast inspiration to TLC followed immediately by a fast expiration, whereas S consisted of a slow inspiration to TLC and a 4- to 5-s pause at TLC prior to forced expiration. We measured esophageal pressure (P _es), peak expiratory flow rate (PEFR), and the EMG activity of the transversus abdominis (Tr) by means of intramuscular fine-wire electrodes. The subjects performed several runs of each maneuver in a random order, and runs with the greatest expiratory P _es were analyzed. In comparison with S, F yielded greater P _es [182 (15) versus 167 (15) cmH₂O; P=0.003)] but similar PEFR [9.8 (0.7) versus 9.6 (0.7) l/s, P>0.05] and EMG activity of the Tr during forced expiration [221 (31) versus 208 (34) a.u., P>0.05]. Further analysis revealed significant EMG activity of Tr during end-inspiration (eccentric contraction) with F maneuvers only [73 (22) versus 32 (17) a.u., P<0.05]. We conclude that the ability of expiratory muscles to generate greater P _es with F maneuvers is related to the sequence of an eccentric contraction, which is followed immediately by concentric contraction in a manner analogous to SSC described in skeletal muscles. Electronic Publication     

郃郎喘必消冲剂的药理研究

本文通过对小鼠急性毒性实验,抗炎实验,对胸腺脾脏的影响及对豚鼠在体、离体气管平滑肌作用实验,观察了郃郎喘必消冲剂的药理学效应。结果表明,该制剂无明显毒性,最大耐受量为1000g/kg/d。它有明显的对抗二甲苯致小鼠耳炎及延长组胺诱发哮喘发作潜伏期的作用,对豚鼠离体气管平滑肌无松驰作用,对小鼠胸腺和脾脏有使其重量减小的趋势,但与对照组比较无显著性差异。     

Cross education of muscular strength during unilateral resistance training and detraining

Abstract. The purpose of the present study was to examine the changes in maximum voluntary isometric contraction (MVC) in the contralateral untrained limb during unilateral resistance training and detraining, and to examine the factors inducing these changes by means of electrophysiological techniques. Nine healthy males trained their plantar flexor muscles unilaterally 4 days·week^–1 for 6 weeks using 3 sets of 10–12 repetitions at 70–75% of one-repetition maximum a day, and detrained for 6 weeks. Progressive unilateral resistance training significantly (P<0.05) increased MVC, integrated electromyogram (iEMG), and voluntary activation in the trained and contralateral untrained limbs. The changes in MVC after training were significantly correlated with the changes in iEMG in both limbs. No significant changes occurred in MVC, voluntary activation, and iEMG in the contralateral limb after detraining. The changes in MVC after detraining did not correlate with the changes in voluntary activation or iEMG in either limb. Training and detraining did not alter twitch and tetanic peak torques in either limb. These results suggest that the mechanisms underlying cross education of muscular strength may be explained by central neural factors during training, but not solely so during detraining. Electronic Publication     

Role of cyclic nucleotides in regulation of pulmonary artery tone in rabbits

The involvement of cAMP- and cGMP-dependent signal systems into the regulation of the contractile reaction of smooth muscles of the rabbit pulmonary arteries was studied using a mechanographic method. For modulation of intracellular level of cyclic nucleotides we used adenylate cyclase activators -adrenoceptor agonist isadrin, guanylate cyclase inhibitor methylene blue, penetrating analog dibutyryl-cAMP, and phosphodiesterase inhibitors. The mechanisms of cAMP- and cGMP-dependent regulation of smooth muscle contractile activity were realized in close interrelationship, and the key component of this was cyclic nucleotide phosphodiesterases. The ratio of activities of phosphodiesterase subtypes in smooth-muscle cells can essentially modulate the adrenergic effects in the pulmonary artery wall and even invert them.     

Effect of an increased calcium ion concentration on electrical and contractile activity of the smooth muscles of the guinea pig ureter

Smooth muscle cells of the guinea pig ureter were studied by the double sucrose gap method. An increase in the calcium ion concentration in the Ringer-Locke solution to 22 mM led to hyperpolarization and to a slight increase in the resistance of the membrane. The amplitude of the first spike potential and the height of the plateau were lowered but the amplitude of the oscillations was increased. In sodium-free Ringer-Locke solution, when the action potential in the smooth muscle cells of the ureter was converted into a simple spike potential, a marked increase in amplitude of the action potential was observed with an increase in the calcium ion concentration.Department of Neuromuscular Physiology, A. A. Bogomolets Institute of Physiology, Academy of Sciences of the Ukrainian SSR, Kiev. (Presented by Academician of the Academy of Medical Sciences of the USSR N. N. Gorev.) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 83, No. 5, pp. 522–526, May, 1977.     

Shared motor innervation between dynamic and static intrafusal muscle fibers in the monkey

Distributions of 25 motor axons to 60 intrafusal muscle fibers of 10 poles of monkey spindle were reconstructed from serial 1 micron thick transverse sections of lumbrical muscles. About 44% of motor axons co-innervated two or more types of intrafusal fiber. The (dynamic) bag1 fiber shared motor innervation with the (static) bag2 or chain fibers in about 50% of spindle poles. Activation of single intrafusal fibers independent of the other fibers of the same intrafusal bundle occurs to a lesser degree in spindles of monkeys than in spindles of cats. Functional implications of this pattern of motor innervation are discussed.