Plastic remodeling of the synaptic apparatus of skeletal muscles under physiological and pathological conditions

The synaptic apparatus of skeletal muscles undergoes continuous remodelling, by adapting to the functioning level of the peripheral neuromuscular apparatus under normal conditions, compensating and restoring its impaired function in pathology. This reorganization has specific features depending on the factors that influence it, such as increased function, decreased or no function, neuronal and nerve damage, synaptic toxin intoxication, autoantibody action, disturbances of trophic influences, etc. Damage to any link of the neuromuscular apparatus due to the above factors is likely to be an essential condition for remodelling.     

Hereditary dominance of fast-twitch fibers in skeletal muscles and relation of thyroid hormone under physiological conditions in rats

This study examined the utility of the domain assessment measures used in the final 2 years at Newcastle medical school in predicting performance ratings in the first year of postgraduate training (internship). Performance ratings were obtained from the clinical supervisors of two graduating classes of the University of Newcastle medical students during their five terms of internship. Three or more ratings were obtained from 57% of interns. Univariate analysis indicated that scores for three of the five domains (professional skills; identification, prevention and management of illness; self-directed learning) were significantly positively correlated with intern performance ratings. Multivariate analysis indicated that only the domain assessing identification, prevention and management of illness was predictive of higher intern performance ratings. The results support the notion that there is some value in the domain assessment model used at Newcastle in predicting the performance of junior doctors.     

不同条件下RH钢包升降系统的选择策略

介绍了RH钢包升降的不同方式,按执行机构可分为液压式和电动式；按设备组成的不同可分为单顶升、双顶升、卷扬提升和四油缸提升.在此基础上进行了对比分析,并总结了RH钢包升降方式选择时应遵循的基本原则,有助于深化对RH工序的理解,为钢铁企业进行设计选择时提供参考.     

Electromyographic activity of respiratory muscles under hyperbaric conditions

Two subjects were exposed to neon gas mixture and two others--to helium one. Electromyographic activity of their breathing muscles differed between the two groups depending on both the gas mixture and the steps of compression. Obvious difficulties of breathing with the neon hyperbaric mixture were accompanied by depressing of the EMG amplitude, episodic breaches or hyperactivation of the EMG. The findings suggest a predominant role of the diaphragm activity in hyperbaric conditions.     

Estimation of energy expenditure from heart rate measurements in cattle maintained under different conditions

We examined whether heart rate (HR) could be used to estimate energy expenditure (EE) in cattle. Six Hereford heifers (345 +/- 10.8 kg BW) 12 mo of age were implanted with HR radio transmitters and maintained in individual pens under the following treatments: 1) shade or sun exposure, 2) high- or low-energy diet, and 3) feeding in morning or afternoon. The HR of animals was measured every .5 h during 3 mo; measurements of oxygen consumption and HR were made simultaneously in the morning and in the afternoon while animals were resting and exercising. Average daily HR (52 +/- 4 beats/min) and average daily EE (380 +/- 9 kJ/kg(.75)) in animals on the low-energy diet were less than values in animals on the high-energy diet (94 +/- 4 beats/min and 653 +/- 9 kJ/ kg(.75), respectively). For each animal and within each diet, linear regressions best described the relationship between HR and EE in resting animals, whereas quadratic regressions best described this relationship for exercising animals. The quadratic equation for the exercising animals could also be used for resting animals. In addition, a constant value of EE per heart beat (EE pulse) for each individual resting animal was found and gave accurate estimations. This method was convenient because 1) no exercise equipment was needed to generate the regression equations and 2) EE pulse was less affected by diet than was EE estimated by regression equations. We conclude that HR, a relatively easy measurement, can be useful and accurate in estimating EE. To increase the accuracy of the estimation of EE by HR, the relationship of HR to EE should be established for each animal. In addition, the nutritional regimen for the animal in which EE is estimated should be used for the animal in establishing the relationship.     

Magnetic resonance imaging of skeletal muscles in the polymyositis

Magnetic resonance imaging of skeletal muscles was performed in 11 patients with polymyositis. Two types of muscle lesions were revealed. The first, inflammation, showed increased signal intensity on T2-weighted images and iso-intensity on T1-weighted images. The second, fatty replacement, showed increased signal intensity on both images. The coronal sections could elucidate the extension of the lesion in each affected muscle. Inflammation was relatively diffuse, while homogeneous fatty replacement tended to begin at the lower myotendinous junctions.     

An electrophysiological investigation of skeletal muscles in polymyositis

An electrophysiological study has been made of the extensor digitorum brevis, thenar and hypothenar muscles in 25 patients with chronic and acute polymyositis. It was found a reduction of the number of functioning motor units in some patients with chronic polymyositis and only in one of those affected by acute polymyositis and only in one of those affected by acute polymyositis. The sizes of the surviving units suggested that the results could be explained in terms of a primary muscle involvement mainly in acute polymyositis, while in chronic polymyositis a combination of primary and neurogenic involvement of muscle fibers might take place.     

Expression and epitopic conservation of calponin in different smooth muscles and during development

The synaptic organization of the saccade-related neuronal circuit between the superior colliculus (SC) and the brainstem saccade generator was examined in an awake monkey using a saccadic, midflight electrical-stimulation method. When microstimulation (50-100 microA, single pulse) was applied to the SC during a saccade, a small, conjugate contraversive eye movement was evoked with latencies much shorter than those obtained by conventional stimulation. Our results may be explained by the tonic inhibition of premotor burst neurons (BNs) by omnipause neurons that ceases during saccades to allow BNs to burst. Thus, during saccades, signals originating from the SC can be transmitted to motoneurons and seen in the saccade trajectory. Based on this hypothesis, we estimated the number of synapses intervening between the SC and motoneurons by applying midflight stimulation to the SC, the BN area, and the abducens nucleus. Eye position signals were electronically differentiated to produce eye velocity to aid in detecting small changes. The mean latencies of the stimulus-evoked eye movements were: 7.9 +/- 1.0 ms (SD; ipsilateral eye) and 7.8 +/- 0.9 ms (SD; contralateral eye) for SC stimulation; 4.8 +/- 0.5 ms (SD; ipsilateral eye) and 5.1 +/- 0.7 ms (SD; contralateral eye) for BN stimulation; and 3.6 +/- 0.4 ms (SD; ipsilateral eye) and 5.2 +/- 0.8 ms (SD; contralateral eye) for abducens nucleus stimulation. The time difference between SC- and BN-evoked eye movements (about 3 ms) was consistent with a disynaptic connection from the SC to the premotor BNs.