Enlarged high frequency oscillations of the median nerve somatosensory evoked potential and survival in amyotrophic lateral sclerosis

ObjectiveA large N20 and P25 of the median nerve somatosensory evoked potential (SEP) predicts short survival in amyotrophic lateral sclerosis (ALS). We investigated whether high frequency oscillations (HFOs) over N20 are enlarged and associated with survival in ALS.MethodsA total of 145 patients with ALS and 57 healthy subjects were studied. We recorded the median nerve SEP and measured the onset-to-peak amplitude of N20 (N20o-p), and peak-to-peak amplitude between N20 and P25 (N20p-P25p). We obtained early and late HFO potentials by filtering SEP between 500 and 1 kHz, and measured the peak-to-peak amplitude. We followed up patients until endpoints (death or tracheostomy) and analyzed the relationship between SEP or HFO amplitudes and survival using a Cox analysis.ResultsPatients showed larger N20o-p, N20p-P25p, and early and late HFO amplitudes than the control values. N20p-P25p was associated with survival periods (p = 0.0004), while early and late HFO amplitudes showed no significant association with survival (p = 0.4307, and p = 0.6858, respectively).ConclusionsThe HFO amplitude in ALS is increased, but does not predict survival.SignificanceThe enlarged HFOs in ALS might be a compensatory phenomenon to the hyperexcitability of the sensory cortex pyramidal neurons.     

Simultaneously recorded intracranial and scalp high frequency oscillations help identify patients with poor postsurgical seizure outcome

ObjectiveHigh frequency oscillations (HFO) between 80–500 Hz are markers of epileptic areas in intracranial and maybe also scalp EEG. We investigate simultaneous recordings of scalp and intracranial EEG and hypothesize that scalp HFOs provide important additional clinical information in the presurgical setting.MethodsSpikes and HFOs were visually identified in all intracranial scalp EEG channels. Analysis of correlation of event location between intracranial and scalp EEG as well as relationship between events and the SOZ and zone of surgical removal was performed.Results24 patients could be included, 23 showed spikes and 19 HFOs on scalp recordings. In 15/19 patients highest scalp HFO rate was located over the implantation side, with 13 patients having the highest scalp and intracranial HFO rate over the same region. 17 patients underwent surgery, 7 became seizure free. Patients with poor post-operative outcome showed significantly more regions with HFO than those with seizure free outcome.ConclusionsScalp HFOs are mostly located over the SOZ. Widespread scalp HFOs are indicative of a larger epileptic network and associated with poor postsurgical outcome.SignificanceAnalysis of scalp HFO add clinically important information about the extent of epileptic areas during presurgical simultaneous scalp and intracranial EEG recordings.     

Effect of external high-frequency oscillation on severe cardiogenic pulmonary edema

Effective gas exchange can be maintained in animals without endotracheal intubation using external high-frequency oscillation (EHFO). The aim of this study was to evaluate the effect of EHFO in patients with respiratory failure due to severe cardiogenic pulmonary edema. Seven patients were ventilated with EHFO for 2h at 60 oscillations·min⁻¹, with a cuiras pressure of 36 cmH₂O (−26 to +10) and an inspiratory to expiratory ratio of 1:1, with EHFO. Blood gas values and hemodynamic parameters were measured. Significant increases were noted in cardiac index (2.3±0.5 to 2.5±0.5 l·m⁻²;P<0.05), stroke volume index (24±7 to 28±8 ml·m⁻²;P<0.05), and arterial O₂ pressure (Pao₂) (70±4 to 95±23 mmHg;P<0.01) without a change in pulmonary artery wedge pressure at 1 h after EHFO. The respiratory rate decreased from 28±3 to 22 ±3 breaths·min⁻¹ at 5 min after the termination of EHFO (P <0.01). Arterial CO₂ pressure (Paco₂) did not, however, decrease. Increased stroke volume without a change in pulmonary artery wedge pressure (preload) suggests either improved inotropic function of the left ventricle or reduced left ventricular afterload with EHFO. The use of EHFO may be effective not only for gas exchange but also for left ventricular function in patients with severe cardiogenic pulmonary edema.     

An Experimental Study on the Relationship Between Artificial Korotkoff Sounds and Self-Excited Oscillation Using a Circulatory Simulator

In the medical field, Korotkoff sounds have been explained as sounds generated by the disturbed blood flow in the artery. However, in the biomechanics field, Korotkoff sounds are considered to be produced and/or modified by the self-excited oscillation of a collapsed artery. The self-excited oscillation is an oscillation of the arterial wall. In addition, it is influenced by the nonlinear pressure–flow relationships in the artery and the arterial compliance. In this paper, we proposed an arterial-compliance-measuring method, using Korotkoff sounds. We constructed a circulatory simulator with a brachial model that mimics the physiological circulation, because in vivo resolution of nonlinear pressure–flow relationships is very difficult. The simulator was utilized to generate artificial Korotkoff sounds similar to those in auscultation in the brachial model. Additionally, we prepared latex tubes as artificial brachial arteries. In the experiment, we investigated the relationship between the self-excited oscillation and Korotkoff sounds by the distinguishing its frequency characteristics. The frequency of the sounds was changed by the variation of the tube compliance. As a result, we have found that the changes of the sounds largely depended on the difference of the tube compliance in this simulator. In conclusion, Korotkoff sounds contain useful information for predicting brachial arterial compliance. These experiments indicate the effectiveness of noninvasive measurement for brachial arterial compliance using Korotkoff sounds.     

Effects of Repeated Deep Inspirations on Recovery from Methacholine-Induced Airway Narrowing in Normal Subjects

Background. A single deep inspiration (DI) is known to be a potent bronchodilator but it is not known if repeated DI can accelerate sustained recovery from bronchoconstriction. Methods. We induced sustained bronchoconstriction using increasing concentrations of nebulized methacholine (Mch) during tidal breathing and assessed airway narrowing by measuring respiratory resistance (Rrs) using forced oscillation in six healthy subjects. On separate days we examined the effects of DI every 3 minutes and of prohibition of DI on recovery of Rrs for 30 minutes after the end of Mch nebulization. Results. Bronchoconstriction (Rrs ∼ 150% above baseline) was induced. DI during recovery had a transient bronchodilator effect but no cumulative effect. At 30 minutes after end of nebulization (and 2 minutes after the last DI) Rrs was 87% above baseline compared to 93% above baseline when DI was prohibited. Conclusion. Recovery from induced bronchoconstriction with methacholine was slow (∼ 2%/min) and not accelerated by frequent DI.     

YAG激光器谐振腔光振状态的调整

本文介绍了调整谐振腔光振状态的方法和要点，它包括调整谐振腔体和其它的光学部件。本法可应用于YAG激光器谐振腔的维修拆卸重装工作中。     

Corneal D.C. recordings of slow ocular potential changes such as the ERG c-wave and the light peak in clinical work

A set-up for D.C. recordings of slow ocular potentials such as the c-wave of the electroretinogram (ERG) as well as the fast oscillation (FO), the light peak (LP) and the dark trough (DT) in both clinical and experimental work is described. It includes matched calomel half-cells connected by saline-agar bridges to a corneal contact lens on the eye and a reference chamber on the forehead, a low-drift differential-input D.C. amplifier, an A/D converter, a computer, a thermoprinter, a flexible disc memory, a plotter, and a device for light stimulation controlled by the computer.Examples of the usefulness of the set-up in clinical work are shown in the form of D.C. c-wave ERGs of normal subjects as well as of patients with vitelliform macular degeneration, choriocapillaris atrophy, and retinitis pigmentosa. The direct corneal recording of the FO and LP is demonstrated as well. The different origins of the standing potential (SP) of the eye, the ERG c-wave, the FO and the LP are reviewed briefly.     

基因测序确认一例新β地中海贫血基因突变CD112（T→A）

目的 报道1例中国人少见的β地中海贫血基因突变CD112（T→A）／N。方法 根据血常规平均红细胞体积（MCV）和平均血红蛋白含量（MCH）以及血红蛋白电泳的HbF和HbA2对婚检和产检患者筛查地中海贫血，对可疑β地中海贫血患者采用基因扩增反向点杂交法检测常见17个位点突变。对于未发现突变者采用基因测序。结果 患者携带一种中国人少见的B地贫基因突变CD112（T→A）。结论 β地贫基因CD112（T→A）突变的报道丰富了中国人β地贫突变谱。对于指导婚检、产检、遗传咨询具有重要价值。     

MEG Characterization of Spontaneous Alpha Rhythm in the Human Brain

The present piece of research studied the spontaneous alpha rhythm of the human brain by combining the use of a whole-cortex neuromagnetometer and Magnetic Resonance Imaging. Single trials of spontaneous brain activity were recorded from ten human subjects asked to rest, with their eyes either closed or open, in relaxed wakefulness. MEG measurements were conducted over a period of one and a half years. The replicability of the results was confirmed for eight subjects out of ten. For three subjects, the alpha rhythm did not show any reductions due to the opening of the eyes. Both field map pattern and location of the estimated source were persistently stationary during each of the bursts of oscillations of the alpha rhythm. Dipoles were concentrated in clusters, indicating the existence of several spatially distributed sources. The calcarine fissure, the parieto-occipital sulcus and the surrounding occipital and parieto-occipital areas were identified as cortical sites of the brain where the alpha rhythm may originate. For four subjects, the majority of the sources were located near or in the calcarine fissure, while for five subjects, they were located near or in the parieto-occipital sulcus and for the remaining subject they were equally divided between the two generation sites.     

超抗原SEA对CD4~+T细胞TCR V_β链的取用格局

用超抗原葡萄球菌肠毒素A (SEA )在体内或体外刺激C57BL/ 6小鼠 2种不同的TCRVβ链T细胞亚群 (Vβ3+ CD4+ 、Vβ1 1 + CD4+ T细胞 ) ,观察二者对超抗原的免疫应答。结果显示 :体内初次刺激后 ,2种T细胞亚群在刺激后第 2天都发生增殖 ,随后均逐渐下降至对照水平。但第 2次用同样剂量刺激后 ,Vβ3+ CD4+ T细胞群对SEA的再次刺激表现出增殖 ,而Vβ1 1 + CD4+ T细胞群对SEA再次刺激则表现出免疫无能。体外初次、再次刺激也分别获得与体内实验相同的结果。表明超抗原SEA可选择性地取用Vβ3+ CD4+ T细胞群并对其发生增殖 ,即超抗原SEA对CD4+ T细胞TCRVβ链的取用格局各有不同。