The interaction between pain and movement

Study DesignClinical commentary.Introduction/PurposePain and movement are universally relevant phenomena that influence human experiences in readily observable ways. Improved understanding of pain-movement relationships can guide medical and rehabilitative approaches to recovery and decrease risk of dysfunctional long-term consequences of otherwise normal neuromuscular responses. Therefore, the overall intent of this article is to elucidate the relationships between pain and movement as they relate to clinical decision making.ConclusionsMotor output is highly adaptable, can be influenced by multiple mechanisms at various levels along the nervous system, and may vary between individuals despite similar diagnoses. Therefore, interventions need to be individualized and consider both the types of motor response observed (ie, whether the response is protective or maladaptive), and the patient's acute physical activity tolerance when prescribing exercise/movement.     

Chlorpromazine, but not chlorpromazine sulphoxide, stimulates transmitter release from motor nerve terminals

Treatment of frog neuromuscular preparations with chlorpromazine (5 mumol/l) resulted in a marked rise in miniature endplate potential (MEPP) frequency of greater than 100% within 30 min, and an increase in evoked transmitter release (quantal content 5-15) of about 35%. Treatment with chlorpromazine sulphoxide (5 microM), a derivative of chlorpromazine with a much lower affinity for calmodulin, had very little effect on either form of transmitter release. It is concluded that stimulatory effects of calmodulin-binding drugs at the nerve terminal may well be exerted through calmodulin inhibition. The stimulatory effect of chlorpromazine on MEPP frequency was markedly reduced in preparations bathed in EGTA-containing Ca2+-free saline, but the response was largely restored by raising the temperature by 3-4 degrees C. It is argued that despite this partial dependence on [Ca2+]o, stimulation of transmitter secretion by chlorpromazine is likely to be mediated by inhibition of calmodulin-activated Ca2+-ATPases, and consequent elevation of [Ca2+]i.     

A Paradigm for Design of Closed Loop Neuromuscular Electrical Stimulator Control Systems

Abstract: The use of neuromuscular electrical stimulation (NMES) for rehabilitation of gait in spinal patients is widely known. The best results can be obtained with the use of biomechanical sensors and a closed loop NMES system. One of the biggest problems faced in the design of control systems for closed-loop operation, in gait rehabilitation, is the variation of the mechanical conditions during the phases of gait. This work presents a new approach to ease the design of rule-based closed loop systems for operation in conditions such as gait rehabilitation.     

The chronotropic effect of acetylcholine in the presence of vecuronium and atracurium A study in the isolated perfused rabbit heart

The bradycardia produced by 1 microgram acetylcholine in the isolated perfused rabbit heart, in the presence of vecuronium and atracurium, was studied and compared with control. Vecuronium at a concentration of 2.5 micrograms/litre and atracurium 6 micrograms/litre did not enhance the negative chronotropic effect of acetylcholine. Atracurium produced a statistically significant inhibition of the negative chronotropic effect of acetylcholine.     

肝硬化病人乌司他丁预处理对罗库溴铵肌松作用的影响

目的观察肝硬化病人乌司他丁预处理对罗库溴铵肌松作用的影响。方法选择30例患有肝硬化的成年手术病人,随机均分为两组:乌司他丁组(Ⅰ组),静注乌司他丁5000U/kg后1min,静脉给予罗库溴铵0.6mg/kg;生理盐水组(Ⅱ组),静脉给予生理盐水0.1ml/kg后1min,静脉给予罗库溴铵0.6mg/kg。另选15例无肝脏疾患的、ASAⅠ～Ⅱ级择期成年手术病人为对照组(Ⅲ组),处理同Ⅱ组。肌松监测仪检测四个成串刺激(TOF)的变化,记录三组注药后罗库溴铵的起效时间(注药到TOFr=0)、TOF无反应时间(T1=0持续时间)、T1最大抑制程度、临床时效(TOFr恢复至25%时间)、T1恢复至75%时间、恢复指数。结果与Ⅱ、Ⅲ组比较,Ⅰ组插管剂量罗库溴铵的起效时间明显延长(P<0.05)。Ⅱ、Ⅲ组罗库溴铵肌松的起效时间相似。与Ⅱ组比较,Ⅰ、Ⅲ组T1恢复25%时间和恢复指数明显缩短(P<0.05)。Ⅰ、Ⅲ组罗库溴铵肌松的恢复时间相似。结论肝硬化病人乌司他丁预处理延长罗库溴铵的起效时间,但缩短罗库溴铵肌松作用时间。     

Increased in vitro uptake of the complement C3b in the serum of patients with Guillain-Barré syndrome, myasthenia gravis and dermatomyositis

To examine the role of complement in certain autoimmune neuromuscular diseases, we used an in-vitro quantitative complement uptake assay that allows measurement of the capacity of patients' sera to deposit fragments of the third complement component onto sensitized targets. C3 uptake was significantly higher in patients with active dermatomyositis, Guillain-Barré syndrome and myasthenia gravis, compared to inclusion body myositis and controls. The in-vitro C3 uptake assay supports the role of C3b neoantigen and Membranolytic Attack Complex deposition in the target tissues and may be a useful tool to monitor disease activity in patients with complement-mediated neurological disorders.     

Rib-vertebral angle asymmetry in idiopathic, neuromuscular and experimentally induced scoliosis

The concave and convex rib-vertebral angle (RVA) at levels T2–T12 was measured on AP radiographs of 19 patients with right convex idiopathic thoracic scoliosis and 10 patients with major thoracic right convex neuromuscular scoliosis. The difference between the angles on the concave and the convex sides, the RVAD, was calculated. The RVAs were also measured on radiographs from three animal groups in which spinal curves had been induced experimentally in a variety of ways. Group 1 comprised 16 rabbits that had been subjected to selective electrostimulation of the latissimus dorsi, the erector spinae and the intercostal muscles. Group 2 comprised four dead rabbits whose spines had been subjected to manual bending. Group 3 comprised eight rabbits that had undergone mechanical elongation of one rib. In both the idiopathic and the neuromuscular group, the convex RVA was smaller than the concave RVA between levels T2 and T8, with a maximal difference between T4 to T5. From T9 to T12 the concave RVA was smaller than the convex. The RVA in relation to the scoliotic segment, i.e. the apex level of the curve and the two neighbouring vertebrae above and below this level, showed similar results. With increasing Cobb angle the RVADs increased linearly with the greatest difference at the second vertebra above the apex. In the three experimental groups the pattern of the RVADs between T6 to T12 was basically similar to the findings of the clinical study. From the results of these clinical and experimental studies, it is concluded that the typical pattern of the RVAs on the concave and convex sides seems to be independent of the underlying cause of the spinal curvature. It is likely that the RVADs result from a passive mechanical adaptation of the ribs to the lateral curvature of the spine.     

A comparison of acceleromyography and mechanomyography for determination of the dose–response curve of rocuronium in children

In order to compare an acceleromyograph (TOF-Guard^TM) with a mechanomyograph (Grass FT03), the dose–response relationship of rocuronium was simultaneously determined in both arms of 15 children aged 3–11 years during anaesthesia with thiopentone, alfentanil and nitrous oxide. Three subgroups of five children received rocuronium 120, 180 or 240 μg.kg⁻¹ randomly. The effective doses to produce 50% and 95% depression of the first twitch of the train-of-four determined by acceleromyography were 206 and 337 μg.kg⁻¹, respectively, while these values determined by mechanomyography were 151 and 331 μg.kg⁻¹, respectively. The dose–response curve obtained by acceleromyography was steeper and shifted to the right compared with that obtained by mechanomyography (p < 0.0001). The difference between the effective dose producing 50% twitch depression determined by the two devices was highly significant (p < 0.0001). In 13 out of 15 children, the acceleromyograph control train-of-four ratio was significantly greater than unity. Although there was a good correlation ( r  = 0.85) between simultaneous pairs of measurements of neuromuscular block, the acceleromyograph exhibited a bias of −25% relative to the mechanomyograph with wide limits of agreement (−62 to +12%). We conclude that acceleromyographic and mechanomyographic measurements should not be used interchangeably when determining the potency of muscle relaxants.