Polysomnographic assessment of respiratory disturbance during deep propofol sedation for endoscopic submucosal dissection of gastric tumors

AIM To investigate that polysomnographic monitoring can accurately evaluate respiratory disturbance incidence during sedation for gastrointestinal endoscopy compare to pulse oximetry alone.METHODS This prospective observational study included 10 elderly patients with early gastric cancer undergoing endoscopic submucosal dissection(ESD) under propofol sedation. Apart from routine cardiorespiratory monitoring, polysomnography measurements were acquired. The primary hypothesis was tested by comparing the apnea hypopnea index(AHI), defined as the number of apnea and hypopnea instances per hour during sedation, with and without hypoxemia; hypoxemia was defined as the reduction in oxygen saturation by ≥ 3% from baseline.RESULTS Polysomnography(PSG) detected 207 respiratory disturbances in the 10 patients. PSG yielded a significantly greater AHI(10.44 ± 5.68/h) compared with pulse oximetry(1.54 ± 1.81/h, P 0.001), thus supporting our hypothesis. Obstructive AHI(9.26 ± 5.44/h) was significantly greater than central AHI(1.19 ± 0.90/h, P 0.001). Compared with pulse oximetry, PSG detected the 25 instances of respiratory disturbances with hypoxemia 107.4 s earlier on average.CONCLUSION Compared with pulse oximetry, PSG can better detect respiratory irregularities and thus provide superior AHI values, leading to avoidance of fatal respiratory complications during ESD under propofol-induced sedation.     

个体化精准恒定功率运动前、后慢性病患者脉搏波波形特征改变初步分析

目的　探讨个体化精准恒定功率运动对慢性病患者脉搏波波形特征的影响。方法　选取2017年6月在首都医科大学附属北京康复医院接受本团队管理的慢性病（以血糖、血脂、血压异常为主）患者中的11例为慢病组,同期选取在中国医学科学院阜外医院学习的正常人8例为正常组。以心肺运动试验评估制定个体化精准恒定功率运动处方,每天运动30 min,在运动前和运动后5、15、30、40 min测量其桡动脉脉搏波波形。对受试者脉搏波原始数据用Origin作图,对桡动脉脉搏波的上升、下降、切迹或平台等波形特征及其运动前后变化进行定性分析,并比较两组运动前、后切迹出现率。结果　运动前慢病组切迹出现率低于正常组（P=0.010）。运动后两组脉搏波均较运动前的波峰变高、波形变窄。运动后5 、15、30、40 min慢病组切迹出现率同运动前比较,差异无统计学意义（P>0.05）,正常人切迹出现率始终为100.0%;运动后5、15、30 、40 min慢病组切迹出现率与正常组比较,差异无统计学意义（P>0.05）。结论　个体化精准恒定功率运动可改变脉搏波波形,其可能作为运动疗法有效管控慢性病的指标,其机制有待进一步研究。     

Recessive MYH7-related myopathy in two families

Myopathies due to recessive MYH7 mutations are exceedingly rare, reported in only two families to date. We describe three patients from two families (from Australia and the UK) with a myopathy caused by recessive mutations in MYH7. The Australian family was homozygous for a c.5134C > T, p.Arg1712Trp mutation, whilst the UK patient was compound heterozygous for a truncating (c.4699C > T; p.Gln1567*) and a missense variant (c.4664A > G; p.Glu1555Gly). All three patients shared key clinical features, including infancy/childhood onset, pronounced axial/proximal weakness, spinal rigidity, severe scoliosis, and normal cardiac function. There was progressive respiratory impairment necessitating non-invasive ventilation despite preserved ambulation, a combination of features often seen in SEPN1- or NEB-related myopathies. On biopsy, the Australian proband showed classical myosin storage myopathy features, while the UK patient showed multi-minicore like areas. To establish pathogenicity of the Arg1712Trp mutation, we expressed mutant MYH7 protein in COS-7 cells, observing abnormal mutant myosin aggregation compared to wild-type. We describe skinned myofiber studies of patient muscle and hypertrophy of type II myofibers, which may be a compensatory mechanism. In summary, we have expanded the phenotype of ultra-rare recessive MYH7 disease, and provide novel insights into associated changes in muscle physiology.     

Neuronal tuning: Selective targeting of neuronal populations via manipulation of pulse width and directionality

IntroductionMotor evoked potentials (MEP) in response to anteroposterior transcranial (AP) magnetic stimulation (TMS) are sensitive to the TMS pulse shape. We are now able to isolate distinct pulse properties, such as pulse width and directionality and evaluate them individually. Different pulse shapes induce different effects, likely by stimulating different populations of neurons. This implies that not all neurons respond in the same manner to stimulation, possibly, because individual segments of neurons differ in their membrane properties.ObjectivesTo investigate the effect of different pulse widths and directionalities of TMS on MEP latencies, motor thresholds and plastic aftereffects of rTMS.MethodsUsing a controllable pulse stimulator TMS (cTMS), we stimulated fifteen subjects with quasi-unidirectional TMS pulses of different pulse durations (40 μs, 80 μs and 120 μs) and determined thresholds and MEP AP latencies. We then compared the effects of 80 μs quasi-unidirectional pulses to those of 80 μs pulses with different pulse directionality characteristics (0.6 and 1.0 M ratios). We applied 900 pulses of the selected pulse shapes at 1 Hz.ResultsThe aftereffects of 1 Hz rTMS depended on pulse shape and duration. 40 and 80 μs wide unidirectional pulses induced inhibition, 120 μs wide pulses caused excitation. Bidirectional pulses induced inhibition during the stimulation but had facilitatory aftereffects. Narrower pulse shapes caused longer latencies and higher resting motor thresholds (RMT) as compared to wider pulse shapes.ConclusionsWe can tune the aftereffects of rTMS by manipulating pulse width and directionality; this may be due to the different membrane properties of the various neuronal segments such as dendrites.SignificanceTo date, rTMS frequency has been the main determinant of the plastic aftereffects. However, we showed that pulse width also plays a major role, probably by recruiting novel neuronal targets.