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.     

Change in urethral pressure during voluntary pelvic floor muscle contraction and vaginal electrical stimulation

The purpose of the study was to compare the effect of voluntary pelvic floor muscle (PFM) contraction and vaginal electrical stimulation on urethral pressure. Twelve women with genuine stress incontinence, mean age 49.4 years (range 33–66) participated in the study. The urethral and bladder pressures were recorded simultaneously through a double-lumen 8 Ch catheter. The patients first performed three voluntary PFM contractions. Then two electrical stimulators, Conmax and Medicon MS 105, 50 Hz, were used in random order. A visual analog scale was used to measure pain and discomfort. Pain was reported to mean 6.8, SEM 0.64 (range 0.7–9.9) and mean 6.1, SEM 0.81 (range 0–9.1) with Conmax and Medicon MS 105, respectively. The mean paired difference in favor of voluntary contraction with Conmax was ?8.0, SD 6.7,P=0.0067, and with Medicon MS 105 it was ?12.2, SD 5.9,P=0.0022. The results demonstrated that voluntary PFM contraction increased urethral pressure significantly more than did vaginal electrical stimulation.     

Fire in the operating theatre. Evacuation pre–planning may save lives

An operating theatre fire and the steps taken to deal with it are described; the difficulties encountered in evacuating anaesthetised patients are highlighted. Measures which might be taken to prevent recurrence of these problems, and recommendations on the institution of fire drills for the safety of patients and staff are given.     

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.     

电击伤早期处理与预后的关系——附34例病例分析

本文根据34例电击伤临床资料,分析早期处理与病人全身情况、局部损伤愈合以及并发症的关系.并讨论间生态组织的处理原则.结果表明:伤后1天内与伤后3天以上就诊的病人比较,前者全身情况良好,创面感染率低,局部损伤用皮瓣或(和)皮片覆盖效果满意,并发症及截肢率均较低     

Behavioral dissociation of anterodorsal and posteroventral hippocampus by subseizure stimulation in mice

BALB/c mice were bilaterally implanted with bipolar electrodes either in anterodorsal (ADH) or posteroventral hippocampus (PVH) in order to compare the effects of postsession electrical stimulation on memory processes. For each experiment, 30 s after the end of the first session, the animals were stimulated during 80 s. For both hippocampal regions, the stimulation intensity was half of the afterdischarge threshold value. Control groups were naive, ADH and PVH implanted non-stimulated animals. Different appetitive and aversive tasks were used. Subseizure stimulation never created a deficit. Depending on the region of the hippocampus stimulated and on the learning task, a retention enhancement was eventually observed. These data are in agreement with the involvement of hippocampus in initial stages of memory consolidation. Further, the subseizure stimulation permitted a functional dissociation between the two hippocampal regions. Both regions seemed involved in the integration of information, but the anterodorsal part would be rather related to behavioral inhibition, while the posteroventral part would have the capacity to induce an arousal state allowing behavioral flexibility.     

Independent regulation of activation and inactivation phases in non-contractile Ca transients by nicotinic receptor at the mouse neuromuscular junction

Non-contractile Ca²⁺ mobilization (not accompanied by muscle contraction) occurs by the prolonged activation of nicotinic acetylcholine receptor in mouse diaphragm muscles treated with anticholinesterase. To elucidate the regulation properties of non-contractile Ca²⁺ mobilization by nicotinic receptor, the modes of action of competitive and depolarizing neurmuscular blockers were investigated. (+)-Tubocurarine (0.07–0.1 μM), pancuronium (0.05 μM) and -bungarotoxin (0.03–0.06 μM) decreased decay time (T₂, duration of inactivation phase) without changes in rise time (T₁, duration of activation phase) of non-contractile Ca²⁺ transients. These competitive antagonists also suppressed their peak amplitude at higher concentrations than those affectingT₂. Contractile Ca²⁺ transients were not inhibited by these antagonists at the concentrations used. Decamethonium (1 μM), a depolarizing blocker, suppressed the peak amplitude of non-contractile Ca²⁺ transients without affecting their duration. In contrast, succinylcholine (0.3 μM) suppressed both peak amplitude andT₁ without changingT₂, presumably via the receptor desentization. Succinylcholine but not decamthonium inhibited contractile Ca²⁺ transients at the concentrations used. These results demonstrate that the activation and inactivation phase in non-contractile Ca²⁺ transients are independently regulated by nicotinic acetylcholine receptor.     

Cross talk in surface electromyograms of human hamstring muscles.

Signals generated from muscles other than the muscle(s) of interest (cross talk) can confound the interpretation of surface electromyograms (EMGs). In this study, the amount of cross talk in surface EMGs of human hamstring muscles was estimated using a protocol in which the quadriceps femoris was electrically stimulated via the femoral nerve. EMGs were recorded from the vastus lateralis and the medial and lateral hamstring muscle groups. The amplitude of the EMG response of the vastus lateralis to electrical stimulation was adjusted to match that of its maximum voluntary effort (MVE) under isometric conditions. Subsequent power density spectrum analysis showed that the median frequencies of the signals generated by electrical stimulation and MVE were not significantly different. In conventional bipolar recordings, cross talk in lateral hamstring EMGs averaged 17.1% MVE and in medial hamstring EMGs 11.3% MVE (average-rectified values). The double differential technique significantly reduced cross talk to 7.6% MVE for the lateral hamstrings, and to 4.2% MVE for the medial hamstrings. The double differential technique appears to be more selective than the bipolar technique when recording EMGs from muscles with highly active neighbors and thus should be used in such situations. Software simulations of the double differential technique also appear to be more selective than the bipolar technique and may be used when the number of amplifiers available is limited.