基于多显示技术的多焦视诱发反应图像系统的研究

多焦视网膜电图是一种客观的、无创的视功能检查方法，可以同时反映视网膜多个微小区域的视功能，在眼底疾病的早期诊断上有独特的优势。介绍了基于多显示技术的多焦视诱发反应图像系统的原理与设计，利用Windows98以上的微软操作系统特有的多显示技术，控制图形刺激器对视网膜的各个区域分别进行刺激。然后用特制的电极把由视网膜多个区域产生的混合叠加信号提取出来。经放大、A/D转换后送入计算机。计算机利用快速M变换对混合信号进行分离，从而得到视网膜各个区域的反应信号。该系统具有控制简单，检测效果好，成本低等优点，在临床上有广泛的应用前景。     

基于快速M变换的多焦视觉电生理检查系统的设计

多焦视觉电生理是一种客观的、无创的视功能检查方法,可以同时检查视网膜多个微小区域的视功能,在眼底疾病的早期诊断上有独特的优势。本文介绍了多焦视觉电生理检查系统的原理与设计,它利用Windows98以上的微软操作系统特有的多显示技术,控制图形刺激器产生特殊的六边形阵列,由m序列控制六边形阵列的黑白翻转来对视网膜的各个区域分别进行刺激。然后用特制的Burian-Allen电极把由视网膜多个区域产生的混合叠加信号提取出来。信号经过放大、A/D转换后送入计算机。计算机利用快速M变换对混合信号进行分离,从而得到视网膜各个区域的反应信号。快速M变换可以将互相关计算转换为FWT,从而大大节省了计算时间。     

视觉诱发电位,视网膜电图及眼电图的临床应用进展

现代科学研究表明至少有70％的外界信息是通过视觉系统被接受、分析和处理的。在视觉信息的处理和加工过程研究中占重要地位的是神经电活动。目前视觉电生理研究已拓展为神经生物学中取得长足进展的领域。视网膜是神经系统的外周感受器中了解得最清楚的区域之一;而对视皮层细胞结构和功能的研究远较大脑其它区域更为深入和清楚。随着视觉电生理的不断发展,越来越多的研究方法逐渐应用于眼科临床。如视觉诱发电位(Visual Evoked Potential,VEP)、视网膜电图(Electroretinograph,ERG)、眼电图(Electrooculargram,     

172例多焦ERG检测分析

目的对172例患者行多焦视网膜电图检测。方法应用德国罗兰电生理仪检测,采用103个六边形刺激图形,记录172例患者多焦ERG的b波振幅密度值在六环的表现。结果多焦ERG表明各类眼底病变对视网膜损伤程度和范围是不相同的。结论多焦ERG检查具有局部定位和定量功能的诊断和分类,以及为眼底病变的早期诊断治疗提供依据具有重要意义。     

多焦视网膜电图多位点振幅概率图研究

多焦视网膜电图是用于检测视网膜后极部多个位点尤其是黄斑部功能的一种客观的眼电生理检查技术.本文记录并分析120位不同性别、不同年龄正常人的mfERG的103个刺激位点一阶反应振幅密度,按年龄、眼别统计出振幅密度正常值,自动画出异常概率图,并经过6例临床病人的mfERG数据验证,结果证实所得概率图与眼科医生的分析判断一致.     

单眼视神经离断家兔ERG和VEP表现

目的:探讨视神经中的由中枢投向视网膜的中枢性纤维在视觉功能中的调节作用.方法:制作单眼视神经离断家兔模型,切断中枢性纤维与视网膜的联系,但同时不损伤视网膜血循环系统,运用视觉电生理的手段观察手术眼与非手术眼视网膜电图(ERG)和视觉诱发电位(VEP)的变化.结果:手术前后之手术眼以及术后手术眼与非手术眼的ERG的变化之间无统计学意义.结论:中枢性纤维在视觉功能中的调节作用很微弱.     

神经电生理诊断技术规范(续)

正第三章神经电图的检测神经电图(ENG)已发展成为临床神经电生理检查最重要的组成部分,随着现代电子技术的不断发展,检测设备的灵敏度和稳定性不断提高,能够进行检测的项目不断增加,再加上神经电图检测的非创伤性,且受检者的不适感较小易被接受,因此被越来越多地应用于周围神经疾病的临床辅助诊断。     

小鼠角膜接触镜电极的制备和评价

背景：小鼠是常用作研究人类视网膜疾病发生、发展规律和防治措施的动物模型,视觉电生理检查已经成为检测小鼠视网膜功能的常规客观检查手段之一。 目的：研制一种新型的小鼠角膜接触镜电极,并检测其在视网膜电图检查过程中的有效性和重复性。 方法：首先测量不同年龄的C57BL6/J小鼠(共24只)的角膜曲率半径和角膜直径;根据所测量得到的小鼠角膜生物参数制备针对不同年龄段小鼠角膜接触镜;由数控系统车床加工获取角膜接触镜;将电极与角膜接触镜相黏附;另选取12只6周龄C57BL6/J小鼠平均分配到2组分别使用传统环状电极和角膜接触镜电极进行视网膜电图检测,分别记录暗适应和明适应视网膜电图的b波振幅,间隔1周测量1次,共3次;2周裂隙灯显微镜小鼠角膜形态。 结果与结论：小鼠角膜直径在不同年龄的小鼠中具有较大差异,在2.23-3.41 mm;设计小鼠角膜接触镜的曲率为2.00 mm,直径为3.5 mm;小鼠角膜接触镜电极在测量暗适应和明适应b波振幅平均值为传统环状电极的82.7%和80.3%,而反复多次检测时,角膜接触电极稳定性高于传统环状电极;使用角膜接触镜电极检测小鼠角膜新生血管翳明显少于环形电极。表明小鼠角膜接触镜电极可以有效的应用于视觉电生理的检测,虽其测量b波振幅较传统环状电极低,但其在多次测量的稳定性较高,并且在电生理检测过程中可以有效降低小鼠角膜损伤。     

神经电生理检查对臂丛神经损伤的定位诊断

目的:探讨神经电生理检测技术在臂丛神经损伤定位诊断中的作用.方法:对299例单肢体、闭合性臂丛神经损伤的病人根据病情需要分别进行肌电图、神经电图以及体感诱发电位( SEP)检查,并与术中所见对比.结果:全臂丛神经C5 - TI根性完全性损伤63人.其中,根性节前完全性损伤26人,根性节后完全性损伤21人,根性节前节后联合性损伤16人;最高受损部位在臂丛神经干及其以下的115人;最高受损部位在束支部及其以下的121人.通过手术证实诊断符合率在90％以上.结论:对于臂丛神经损伤,应用神经电生理检测技术可以作出较明确的定位诊断.     

电生理学检测在特发性面神经麻痹中应用的研究进展

特发性面神经麻痹是门诊常见疾病,临床面神经功能的评定如House-Brackmann分级,对面神经功能状态判断不够客观、具体,对治疗及预后提供信息尚不充足。电生理检查作为辅助诊断神经肌肉疾病的一种手段,多年来各种各样的电生理检测已应用于临床,如神经兴奋性试验(NET)、最大刺激试验(MST)、神经电图(ENoG)和瞬目反射(BR)、肌电图(EMG)等。本文对电生理学检测在特发性面神经麻痹中应用的研究进展作一综述。     

Glaucoma detection by wavelet-based analysis of the global flash multifocal electroretinogram

The current clinical analysis of the multifocal electroretinography (mfERG) recordings for detecting glaucoma is based on standard signal morphology, measuring amplitudes and latencies. However, this analysis is not sensitive enough for detection of small changes in the multifocal electroretinogram signals. Other, more sophisticated, analysis methods should be explored to improve the sensitivity of this diagnostic technique, such as the discrete wavelet transform, proposed in this paper. We present an alternative method for the detection of open angle glaucoma based on the characterization of global flash mfERG signals. The digital signal processing technique is based on wavelets, hitherto unused in this field, for detection of advanced-stage glaucoma. Two markers were obtained from the recorded signals by applying the discrete wavelet transform, which help discriminate healthy from glaucomatous signals.     

Loss of functional K+ channels encoded by ether-à-go-go-related genes in mouse myometrium prior to labour onset

There is a growing appreciation that ion channels encoded by the ether-à-go-go-related gene family have a functional impact in smooth muscle in addition to their accepted role in cardiac myocytes and neurones. This study aimed to assess the expression of ERG1–3 (KCNH1–3) genes in the murine myometrium (smooth muscle layer of the uterus) and determine the functional impact of the ion channels encoded by these genes in pregnant and non-pregnant animals. Quantitative RT-PCR did not detect message for ERG2 and 3 in whole myometrial tissue extracts. In contrast, message for two isoforms of mERG1 were readily detected with mERG1a more abundant than mERG1b. In isometric tension studies of non-pregnant myometrium, the ERG channel blockers dofetilide (1 μ m ), E4031 (1 μ m ) and Be-KM1 (100 n m ) increased spontaneous contractility and ERG activators (PD118057 and NS1643) inhibited spontaneous contractility. In contrast, neither ERG blockade nor activation had any effect on the inherent contractility in myometrium from late pregnant (19 days gestation) animals. Moreover, dofetilide-sensitive K⁺ currents with distinctive 'hooked' kinetics were considerably smaller in uterine myocytes from late pregnant compared to non-pregnant animals. Expression of mERG1 isoforms did not alter throughout gestation or upon delivery, but the expression of genes encoding auxillary subunits (KCNE) were up-regulated considerably. This study provides the first evidence for a regulation of ERG-encoded K⁺ channels as a precursor to late pregnancy physiological activity.     

Identification of appropriate primitive polynomials to avoid cross-contamination in multifocal electroretinogram responses

The basis of the multifocal/electroretinogram is the use of a decimated m-sequence for simultaneous and independent stimulation of many areas of the visual pathway. The purpose of this study was to investigate the effects of cross-contamination from higher orders of the response. A series of primitive polynomials were found by construction of finite fields. The first-order ERG response was formed by cross-correlation of m-sequence with the physiological response. A second-order response was formed by investigation of particular flash sequences of the stimulation sequence and cross-correlation of a second-order m-sequence with the physiological response. Zech logarithms were used to identify cross-contamination between the various first and second-order sequences. Tables of good and bad primitive polynomials were constructed for degrees 12–16, and the effects of window length and decimation length were examined. When the sequence was decimated into 128 areas, and a window of length 16 was examined, cross-contamination occurred in all sequences generated from primitive polynomials of degree less than or equal to 12, but in only 26% of degree 14, and 5.6% of degree 16. A photodiode (artificial eye) was used in an experiment to construct trace arrays showing responses from 61 individual areas. Additional waveforms were present on the trace array when the experiment was carried out with a bad primitive polynomial. The use of finite field theory to generate primitive polynomials and Zech logarithm analysis allowed prediction of which primitive polynomials were suitable for m-sequence generation for multifocal electroretinography. Practical investigations supported the theoretical analysis. This has important implications for developers of multifocal electrophysiology systems.     

An instrument to investigate temporal processing mechanisms with the multifocal ERG

The multifocal ERG technique is a powerful method of studying the function of different areas of the retina. Display systems such as the CRT, which are commonly used for stimulation, are subject to limitations such as those imposed by the raster method of scanning. This work describes a novel stimulating display using LEDs that retains the established hexagonal areas but overcomes some of the limitations of the CRT display systems. The design and construction of the instrument is described together with some preliminary results.     

An instrument to investigate temporal processing mechanisms with the multifocal ERG

The multifocal ERG technique is a powerful method of studying the function of different areas of the retina. Display systems such as the CRT, which are commonly used for stimulation, are subject to limitations such as those imposed by the raster method of scanning. This work describes a novel stimulating display using LEDs that retains the established hexagonal areas but overcomes some of the limitations of the CRT display systems. The design and construction of the instrument is described together with some preliminary results.     

Removal of eye movement artefacts from single channel recordings of retinal evoked potentials using <Emphasis Type="Italic">synchronous</Emphasis> dynamical embedding and independent component analysis

A system is described for the removal of eye movement and blink artefacts from single channel pattern reversal electroretinogram recordings of very poor signal-to-noise ratios. Artefacts are detected and removed by using a blind source separation technique based on the jadeR independent component analysis algorithm. The single channel data are arranged as a series of overlapping time-delayed vectors forming a dynamical embedding matrix. The structure of this matrix is constrained to the phase of the stimulation epoch: the term synchronous dynamical embedding is coined. A novel method using a marker channel with a non-independent synchronous feature is employed to identify the single most relevant source estimation for reconstruction and signal recovery. This method is non-lossy, all underlying signal being recovered. In synthetic datasets of defined noise content and in standardised real data recordings, the performance of this technique is compared to conventional fixed-threshold hard-limit rejection. The most significant relative improvements are achieved when movement and blink artefacts are greatest: no improvement is demonstrable for the random noise only situation.     

The identification of cells containing JC papovavirus DNA in progressive multifocal leukoencephalopathy by combined in situ hybridization and immunocytochemistry

A double-labelling technique combining in situ hybridization and immunocytochemistry is described which was used to characterize cells in the central nervous system containing JC virus DNA in formalin-fixed, paraffin-embedded tissues from four cases of progressive multifocal leukoencephalopathy. All four cases showed positive nuclear labelling for JC virus in both oligodendrocytes and astrocytes. The latter gave a strongly positive cytoplasmic staining reaction using antibodies to glial fibrillary acidic protein and vimentin. No nuclear labelling of neurones or endothelial cells was noted. The results confirm previous suggestions that glia are the main cells infected by JC virus in this disorder and show that the distribution of viral DNA in the brain is more extensive than suggested by routine microscopy alone. In situ hybridization for JC virus may be useful in confirming the diagnosis of progressive multifocal leukoencephalopathy in both surgical biopsies and post-mortem brain tissue.     

Molecular diagnostics of a single multifocal non-small cell lung cancer case using targeted next generation sequencing

Histological and molecular subtyping of non-small cell lung cancer (NSCLC) is important for predicting survival and drug response in these patients. Up to 8 % of NSCLC are multifocal and these tumor foci are often clonally related. Multiple foci can however also represent different primary tumors, with prognostic and therapeutic consequences. We describe a patient with multifocal NSCLC from which we obtained tissue from two separate lesions. With routine conventional molecular determinations, the clonal relationship between the two lesions was determined. In addition, targeted next generation sequencing with the Ion Torrent Personal Genome Machine (PGM) was performed to explore the accuracy and additional value of this relatively new technique. The two tumors of this patient showed different activating epidermal growth factor receptor (EGFR) mutations, EGFR amplification status, TP53 mutation status, and loss of heterozygosity patterns. With the PGM, all conventional detected mutations were confirmed, and an additional variant of unknown significance in ATM was detected in one of the tumors. The multifocal NSCLC of this patient represents two unrelated primary tumors. Our results suggest that multifocal NSCLC should be considered as potentially multiple primary tumors. As the presence of activating EGFR mutations has important therapeutic consequences, EGFR testing should be performed on all tumor foci present. In the present case, targeted next generation sequencing using the PGM appeared to be accurate and comparable with conventional molecular determinations. However, the application of the PGM in routine pathology molecular diagnostics needs validation in larger series of cases.     

Clonal origin of hepatitis B virus-associated hepatocellular carcinoma

The clonal origin of tumors was studied in two multifocal hepatocellular carcinomas arising from hepatitis B viral cirrhosis. DNA extracted from several tumor nodules was analyzed for the presence of hepatitis B virus genome by the Southern blot technique. Unique clonal integration of the viral DNA sequences occurred in both cases. In each case, identical integration bands occurred among multiple nodules of liver tumor. These results are strong evidence of a unicentric origin of these tumors, although the tumors' gross appearance is suggestive of multifocal origin.