Influence of posture on blink reflex prepulse inhibition induced by somatosensory inputs from upper and lower limbs

BackgroundPrepulse inhibition (PPI) is a neurophysiological phenomenon whereby a weak stimulus modulates the reflex response to a subsequent strong stimulus. Its physiological purpose is to avoid interruption of sensory processing by subsequent disturbing stimuli at the subcortical level, thereby preventing undesired motor reactions. An important hub in the PPI circuit is the pedunculopontine nucleus, which is also involved in the control of posture and sleep/wakefulness.ObjectiveTo study the effect of posture (supine versus standing) on PPI, induced by somatosensory prepulses to either upper or lower limb. PPI was measured as the percentage inhibition of the blink reflex response to electrical supraorbital nerve (SON) stimulation.MethodsSixteen healthy volunteers underwent bilateral blink reflex recordings following SON stimulation either alone (baseline) or preceded by an electrical prepulse to the median nerve (MN) or sural nerve (SN), both in supine and standing. Stimulus intensity was 8 times sensory threshold for SON, and 2 times sensory threshold for MN and SN, respectively. Eight stimuli were applied in each condition.ResultsBaseline blink reflex parameters did not differ significantly between the two postures. Prepulse stimulation to MN and SN caused significant inhibition of R2. In supine but not in standing, R2 was significantly more inhibited by MN than by SN prepulses. In standing, SN stimulation caused significantly more inhibition of R2 than in supine, while the inhibition caused by MN prepulses did not differ significantly between postures.SignificancePPI induced by lower limb afferent input may contribute to postural control while standing.     

21 d-6°头低位卧床期间运动训练对动态姿态平衡的影响

目的探讨21 d-6°头低位卧床和卧床运动训练对动态姿态平衡和控制功能的影响. 方法 10名健康男性青年被试者分为卧床对照组和卧床训练组,每组5人,卧床期间训练组每天进行2次、每次30 min逐级增加负荷的头低位功率自行车训练;分别于卧床前和卧床后21 d进行了动态姿态平衡和双膝等速肌力的测试. 结果与卧床前相比,对照组动态本体感觉得分和运动控制适应能力明显降低,双膝相对峰力矩明显降低,同时伴有腘绳肌与股四头肌峰力矩屈/伸比值的明显增加;训练组动态本体感觉得分和运动控制适应能力明显高于对照组,而腘绳肌与股四头肌峰力矩屈/伸比值无明显改变. 结论 21 d-6°头低位卧床运动训练能够明显改善卧床后动态姿态平衡及其动态运动适应功能.     

结肠CT扫描技术初探

目的 :通过分析比较结肠扫描不同充填剂与不同体位的方法 ,探讨出最佳充填剂与最佳体位以提高结肠 CT扫描质量。方法 :分别对 4 0例结肠 CT扫描病人采用不同的充填剂 ,与不同的体位 ,评价不同的充填剂与不同体位的优缺点。结果 :水作为充填剂组病灶显示情况明显优于泛影萄胺组且伪影少 ,选择不同体位组图像质量也明显优于常规体位组。结论 :结肠 CT扫描时应首选水作为充填剂 ,根据病变不同选择不同的体位 ,有利于图像质量的提高     

Posture-induced nasal obstruction in patients with allergic rhinitis

Nasal resistance is affected by posture. In this study, the effects of supine and lateral recumbent positions were investigated in eight normal subjects and 31 patients with allergic rhinitis. Of the 31 patients with allergic rhinitis, five showed unilateral complete nasal obstruction and one patient showed bilateral complete obstruction during the change of posture. Total nasal resistance had a tendency to increase with repeating the change of posture (a paired t-test, P < 0.05). The supine and lateral recumbent positions did not induce variable changes in total nasal resistance in normal subjects. Posture induces complete nasal obstruction in the supine or lateral recumbent positions in some patients with allergic rhinitis.     

Position as a variable for cardiovascular responses during exercise

Twenty-one normal young male subjects underwent resting and exercise (bicycle) radionuclide angiography in the full supine and 70 degrees upright tilt positions in order to examine the effects of position on left ventricular size and performance, hemodynamics, and exercise duration. All subjects also underwent full (90 degrees) upright bicycle ergometry with respiratory gas analysis to establish the level of maximal exercise capacity for each. Body position significantly (p less than 0.05) affected resting and exercise cardiovascular parameters. End-diastolic and endsystolic left ventricular volumes and stroke volume were larger in the supine position, both at rest and during exercise. The cardiac output at rest and during exercise were comparable for the two positions; an increase in resting and exercise heart rate in the 70 degrees tilt position compensated for the reduced stroke volume of this posture. At maximal exercise, the 70 degrees upright position was associated with a greater response in left ventricular ejection fraction, otherwise this parameter was not position related. Exercise capacity, in terms of duration and workload, was significantly higher in the supine (1870 +/- 390 s) and full upright (1830 +/- 250 s) positions than in the 70 degrees tilt position (1730 +/- 260 s). Changes in body position significantly alter parameters of ventricular, cardiovascular, and exercise performance.     

Effects of posture and pneumoperitoneum during anaesthesia on the indices of left ventricular filling

Background. Laparoscopic surgery requires the use of pneumoperitoneum (PP). When combined with positional changes, pneumoperitoneum may cause marked circulatory alterations.
Methods. Eight anaesthetized cardiovascularly healthy patients, scheduled for laparoscopic cholecystectomy, were studied before and during pneumoperitoneum in three different postures (supine, Trendelenburg and reversed Trendelenburg), employing transesophageal echocardiography and pulmonary artery pressure monitoring.
Results. PP significantly increased end-diastolic area (EDA) and pulmonary capillary wedge pressure (PCWP) irrespective of posture. PCWP was significantly influenced by postural changes, whereas EDA was not. Further, changes in EDA and PCWP covaried during the investigation, but showed no linear correlation. Systolic function, measured as end-systolic area (ESA) and fractional area shortening (FAS), was not altered. Diastolic function, as assessed by the velocity rate of the trans-mitral flow during the early filling phase (E) and the atrial contraction (A), showed no change of the E/A ratio, whereas after the induction of PP there was a significant reduction of the E component.
Conclusions. In cardiovascularly healthy patients, the left ventricular volume is increased during pneumoperitoneum. Further, changes in invasive pressure determinations (PCWP) do not correlate linearly with changes in volume indices of left ventricular filling (EDA).     

改变产妇体位矫正胎方位170例临床观察

目的 探讨产程中改变产妇体位以矫正胎位的临床效果。方法 选择潜伏期经内诊或B超确诊为枕后位的初产妇170例,随机分成研究组和对照组,各85例。研究组在产程中指导产妇取侧俯卧位,对照组孕妇任意体位。结果 研究组72例(84.71％)胎儿从枕后位转至枕前位经阴道娩出。剖宫产13例,占15.29％,对照组经阴道娩出仅28例,22.94％,剖宫产57例,67.06％。两组比较,P<0.01),差异有非常显著性。两组产程比较,P<0.01,差异有极显著性。结论 在产程中指导产妇取胎儿脊柱侧行同侧侧俯卧位矫正胎头枕后位可降低难产发生率及剖宫产率,有助于提高分娩质量。     

辅助发音器治疗腭咽闭合不全前后舌位置及运动特点比较研究

目的:讨论S-A治疗前后舌位置及运动形态对腭裂患者的影响。方法:采用标准头颅侧位X线片对腭裂术后VPI患者,S-A治疗前后、语音治疗一年后舌静止及运动形态进行了研究。结果:静止位S-A治疗后舌背明显降低,语音治疗后舌位逐渐抬高,发/a:/音时S-A治疗后及语音治疗一年后,不良代偿习惯逐渐消除,语音清晰度明显升高。结论:VPI的矫正及语音治疗对根除舌不良代偿习惯,获得清晰准确的发音具有重要意义。     

综合矫正训练方案联合中药熏蒸治疗上交叉综合征疗效观察

<正>上交叉综合征(upper crossed syndrome,UCS)是指因上半身长期处于不良姿势,造成相关肌群功能失衡,进而引起颈肩背部疼痛不适、胸闷、睡眠障碍等一系列不良症状的一种亚健康状态^[1]。UCS常见的体态是圆肩、驼背、头前倾^[2]。目前临床上主要通过纠正局部的肌肉失衡来治疗UCS,常用的方法有运动疗法、肌肉能量技术、针灸和推拿等^[3]。     

Control of upright standing posture during low-frequency linear oscillation

We examined the effects of anteroposterior movement of a sled on human upright standing. Each of six healthy men stood on the platform of a sled in the dark. The sinusoidal acceleration was provided, from 0.02 to 0.04 G, followed by 0.06 and 0.08 G, at a stroke length from 6 to 10 m and then to 14 m. Low acceleration (0.02 and 0.04 G) induced body sway, pivoting on the ankle joint. High acceleration (0.06 and 0.08 G) increased body sway, but the head-neck joint remained locked upright. The electromyographic recordings of the lower leg muscles revealed continuous tonic EMG activities of the gastrocnemius and tibialis anterior muscles at acceleration of 0.02 and 0.04 G, while reciprocal activation was observed at 0.06 and 0.08 G. During head movement, the neck muscles were slightly activated tonically at acceleration of 0.02 and 0.04 G, but they were markedly and tonically activated at 0.06 and 0.08 G. We speculate that the sled oscillation caused body sway in proportion to the acceleration, with the ankle joint playing a principal role. Analysis of neck movement also revealed that the head was held in a fixed upright position, indicating that the vestibulocollic reflex might tonically activate the neck muscles.