Chemoreceptors,baroreceptors, and autonomic deregulation in children with obstructive sleep apnea

Obstructive sleep apnea (OSA) is highly prevalent sleep disorder of breathing in both adults and children that is fraught with substantial cardiovascular morbidities, the latter being attributable to a complex interplay between intermittent hypoxia (IH), episodic hypercapnia, recurrent large intra-thoracic pressure swings, and sleep disruption. Alterations in autonomic nervous system function could underlie the perturbations in cardiovascular, neurocognitive, immune, endocrine and metabolic functions that affect many of the patients suffering from OSA. Although these issues have received substantial attention in adults, the same has thus far failed to occur in children, creating a quasi misperception that children are protected. Here, we provide a critical overview of the evidence supporting the presence of autonomic nervous system (ANS) perturbations in children with OSA, draw some parallel assessments to known mechanisms in rodents and adult humans, particularly, peripheral and central chemoreceptor and baroreceptor pathways, and suggest future research directions.     

生活方式干预对糖耐量异常者动脉内膜厚度及弹性的影响

目的探讨饮食、运动等生活方式干预对糖耐量异常者颈动脉内膜中膜厚度与臂踝脉搏波传导速度的影响。方法收集糖耐量异常者162例,随机分为78例对照组,84例干预组;对照组给予每3个月1次的糖尿病健康知识宣教(电话),干预组在此基础上进行为期24个月的生活方式干预,并每月随访1次。每例均采用超声及全自动动脉硬化仪测定颈动脉内膜中膜厚度与臂踝脉搏波传导速度。各组均进行前后自身对照和组间对照,并评价干预效果。结果经过24个月生活方式干预,干预组糖尿病累计发病率较对照组显著下降;干预组较干预前甘油三酯、口服糖耐量试验2 h血糖显著降低(P<0.05),其余指标经对比后差异无统计学意义;干预组与对照组比较,两组颈动脉内膜中膜厚度有显著性差异(P<0.05),除臂踝脉搏波传导速度、体质指数、高密度脂蛋白外,其余各项指标均有显著改善(P<0.05或P<0.01)。结论生活方式干预能有效改善糖耐量异常患者的代谢状态,降低糖尿病发病率,并能延缓其血管病变的发展;强化生活方式干预应在糖耐量异常人群中大力推行。     

Perspectives on Cardiovascular Fitness and SCI

ABSTRACT

The purpose of these papers is to review and discuss the fundamental concepts and problems underlying cardiovascular fitness and spinal cord injury. Particular attention is paid to several modes of exercise available to individuals with spinal cord injury (SCI)- voluntary arm-crank and wheelchair ergometry, electrical stimulation leg cycle ergometry, and combined voluntary arm-cranking and electrical stimulation leg (hybrid) exercise. The effects of level of injury, active muscle mass, and sympathetic dysfunction upon acute central hemodynamic adjustments during exercise testing and chronic training adaptations are discussed for both quadriplegics and paraplegics. Several topics for future research are suggested.     

Pulse Wave Velocity for Assessment of Arterial Stiffness Among People With Spinal Cord Injury: A Pilot Study

Background/Objective: The most significant complication and leading cause of death for people with spinal cord injury (SCI) is coronary artery disease (CAD). It has been confirmed that aortic pulse wave velocity (PVW) is an emerging CAD predictor among able-bodied individuals. No prior study has described PWV values among people with SCI. The objective of this study was to compare aortic (the common carotid to femoral artery) PWV, arm (the brachial to radial artery) PVW, and leg (the femoral to posterior tibial artery) PVW in people with SCI (SCI group) to able-bodied controls (non-SCI group).

Methods: Participants included 12 men with SCI and 9 non-SCI controls matched for age, sex, height, and weight. Participants with a history of CAD or current metabolic syndrome were excluded. Aortic, arm, and leg PVW was measured using the echo Doppler method.

Results: Aortic PVW (mean ± SD) in the SCI group (1,274 ± 369 cm/s) was significantly higher (P < 0.05) than in the non-SCI group (948 ± 110 cm/s). There were no significant between-group differences in mean arm PVW (SCI: 1,152 ± 193 cm/s, non-SCI: 1,237 ± 193 cm/s) or mean leg PVW (SCI: 1,096 ± 1 73 cm/s, non-SCI: 994 ±178 cm/s) values.

Conclusions: Aortic PVW was higher among the SCI group compared with the non-SCI group. The higher mean aortic PVW values among the SCI group compared with the non-SCI group indicated a higher risk of CAD among people with SCI in the absence of metabolic syndrome.     

Progressive femoral cortical and cancellous bone density loss after uncemented tapered-design stem fixation

Background Aseptic implant loosening and periprosthetic bone loss are major problems after total hip arthroplasty (THA). We present an in vivo method of computed tomography (CT) assisted osteodensitometry after THA that differentiates between cortical and cancellous bone density (BD) and area around the femoral component.

Method Cortical and cancellous periprosthetic femoral BD (mg CaHA/mL), area (mm²) and contact area between the prothesis and cortical bone were determined prospectively in 31 patients 10 days, 1 year, and 6 years after uncemented THA (mean age at implantation: 55 years) using CT-osteodensitometry.

Results 6 years postoperatively, cancellous BD had decreased by as much as 41% and cortical BD by up to 27% at the metaphyseal portion of the femur; this decrease was progressive between the 1-year and 6-year examinations. Mild cortical hypertrophy was observed along the entire length of the diaphysis. No statistically significant changes in cortical BD were observed along the diaphysis of the stem.

Interpretation Periprosthetic CT-assisted osteodensitometry has the technical ability to discriminate between cortical and cancellous bone structures with respect to strain-adapted remodeling. Continuous loss of cortical and cancellous BD at the femoral metaphysis, a homeostatic cortical strain configuration, and mild cortical hypertrophy along the diaphysis suggest a diaphyseal fixation of the implanted stem. CT-assisted osteodensitometry has the potential to become an effective instrument for quality control in THA by means of in vivo determination of periprosthetic BD, which may be a causal factor in implant loosening after THA.     

Applied cerebral physiology

The brain is an exquisitely sensitive organ, requiring a constant supply of blood, oxygen, and glucose to function. Cerebral blood flow is autoregulated to provide a near constant blood supply despite fluctuations in whole body physiology. The blood–brain barrier acts to ensure that the brain microenvironment remains tightly regulated. The pressure within the cranium must also be tightly controlled to maintain optimal cerebral perfusion and ultimately prevent herniation of brain parenchyma. Several physiological parameters can be monitored including intracranial pressure, cerebral oxygenation and metabolic stress and clinical use is increasing including in traumatic brain injury and subarachnoid haemorrhage patients.     

不同脉宽条件下人工耳蜗植入者术中 电诱发听性脑干反应检测的特点分析

摘要：目的比较不同脉宽条件下人工耳蜗植入者术中电诱发听性脑干反应（electrically evoked auditory brainstem response,EABR）的特点,分析脉宽与EABR波V引出率和阈值之间的关系,总结不同脉宽条件对EABR波V引出率和阈值的影响,选择更优化的EABR脉宽测试参数。方法无残余听力的人工耳蜗植入患者24例作为实验组,其中耳蜗形态正常12例、大前庭导水管综合征（large vestibular aqueduct syndrome,LVAS）4例、Mondini畸形4例、共同腔畸形（common cavity deformation,CCD）2例、内听道狭窄2例;筛选条件相近的24例有残余听力的人工耳蜗植入者配对作为对照组。应用改装的Cochlear Freedom人工耳蜗及自制的铂铱合金球电极对拟行人工耳蜗植入的两组者术中分别给予50、100、200 μs不同脉宽的电刺激,Bio logic Navigator Pro听觉诱发电位仪记录不同脉宽条件下EABR波V引出率和阈值。结果脉宽50、100、200 μs时,EABR波V引出率实验组（均为91.7%）低于对照组（分别为100%、100%、95.8%）,差异无统计学意义（P均>0.05）;而EABR阈值实验组［分别为(183.73±8.96)CL、(151.28±10.05)CL、(120.56±12.82)CL］高于对照组［分别为(175.50±9.14)CL、(142.71±11.45)CL、(110.63±10.24)CL］,差异均具有统计学意义(t值分别为18.87、16.82、17.64,P均<0.05)。结论蜗内单极刺激能诱发出良好的EABR波形,无残余听力的患者EABR阈值要明显高于有残余听力的患者。相对于脉宽200 μs,50、100 μs时EABR波形波V引出率高;脉宽50 μs波形分化更好、动态范围广,内耳畸形严重可能需要适当加大刺激量（如将脉宽改为100 μs）。     

The Nobel Prize and otolaryngology: ‘Papa Gunnar’s’ promotion of his peers Gustav Killian and Themistocles Gluck

Objectives: This study is part of a larger project investigating the enactment of excellence in medicine, with a focus on the Nobel Prize. It takes a closer look at two promising candidates for the Prize in the 1920s and 1930s, Gustav Killian and Themistocles Gluck, and aims at reconstructing their Nobel careers as well as taking Gunnar Holmgren’s role as a nominator and evaluator behind the curtains into account.

Method: Besides the files collected at the Nobel Archive, the paper is based on a review of scientific publications and ergo-biographical sketches.

Results: An analysis of Nobel Prize nominations and evaluations offer a unique perspective to study aspects of the history of otolaryngology.

Conclusion: Using original files in the archive of the Nobel committee for physiology or medicine in Sweden, this historical vignette explores judgments of scientific innovation and performance in the history of otolaryngology during the first half of the 20th century. This study shows that Gunnar Holmgren, the founder of Acta Oto-Laryngologica in 1918, repeatedly put forward scholars within the field as prime contenders for the award.     

Podocyte Purinergic P2X4 Channels Are Mechanotransducers That Mediate Cytoskeletal Disorganization

Podocytes are specialized, highly differentiated epithelial cells in the kidney glomerulus that are exposed to glomerular capillary pressure and possible increases in mechanical load. The proteins sensing mechanical forces in podocytes are unconfirmed, but the classic transient receptor potential channel 6 (TRPC6) interacting with the MEC-2 homolog podocin may form a mechanosensitive ion channel complex in podocytes. Here, we observed that podocytes respond to mechanical stimulation with increased intracellular calcium concentrations and increased inward cation currents. However, TRPC6-deficient podocytes responded in a manner similar to that of control podocytes, and mechanically induced currents were unaffected by genetic inactivation of TRPC1/3/6 or administration of the broad-range TRPC blocker SKF-96365. Instead, mechanically induced currents were significantly decreased by the specific P2X purinoceptor 4 (P2X₄) blocker 5-BDBD. Moreover, mechanical P2X₄ channel activation depended on cholesterol and podocin and was inhibited by stabilization of the actin cytoskeleton. Because P2X₄ channels are not intrinsically mechanosensitive, we investigated whether podocytes release ATP upon mechanical stimulation using a fluorometric approach. Indeed, mechanically induced ATP release from podocytes was observed. Furthermore, 5-BDBD attenuated mechanically induced reorganization of the actin cytoskeleton. Altogether, our findings reveal a TRPC channel-independent role of P2X₄ channels as mechanotransducers in podocytes.     

心肌型脂肪酸结合蛋白联合APACHEⅡ评分对急性肺栓塞病情及预后的评估价值

目的 探讨心肌型脂肪酸结合蛋白(heart-type fatty acid-binding protein,H-FABP)联合急性生理学与慢性健康状况评分(acute Physiology and Chronic Health Evaluation,APACHEⅡ)在评估急性肺栓塞(acute pulmonary embolism,APE)患者病情严重程度及预后的临床价值.方法 回顾性分析本院2010年1月至2015年1月确诊的160例APE患者临床资料[男92例,女68例,年龄(51±12)岁].根据APE患者病情严重程度将其分为:低危组[n =58,男33例,女25例,年龄(50±13)岁]、中危组[n=54,男30例,女24例,年龄(54±12)岁]及高危组[n =48,男29例,女19例,年龄(52±10)岁];根据临床转归,将其分为存活组(n=132)和死亡组(n=28),比较不同组间H-FABP和APACHEⅡ评分的差异,评价H-FABP(酶联免疫吸附法测定)和APACHEⅡ评分对评估APE患者病情严重程度及预后的临床价值.结果 随着APE患者病情严重程度的增加,H-FABP和APACHEⅡ评分指标水平显著升高(P＜0.05);死亡组H-FABP和APACHEⅡ评分水平显著高于存活组(P＜0.05).相关性分析显示,血浆H-FABP与APACHEⅡ评分水平呈正相关(r=0.71,P=0.000).ROC曲线分析显示,H-FABP曲线下面积为0.854 (95％ CI 0.784～ 0.927),其血浆H-FABP＞ 13.3μg/L时,诊断APE的病情严重程度及预后的敏感性和特异性分别为81.0％和79.4％;APACHEⅡ评分曲线下面积为0.861 (95％ CI0.812～0.932),其APACHEⅡ评分＞19.2分时诊断APE的病情严重程度及预后的敏感性和特异性分别为77.8％和80.4％.二者指标串联诊断敏感性及特异性分别为88.9％和87.6％,ROC曲线下面积为0.914(95％ CI 0.825～0.948),其明显高于单一H-FABP和APACHEⅡ评分指标.结论 H-FABP联合APACHEⅡ评分评估APE患者病情严重程度及预后的敏感性及特异性显著优于单一H-FABP和APACHEⅡ评分指标,其可为临床APE患者个体化治疗,降低其病死率提供客观依据.