多焦视网膜电图电信号的提取技术

介绍了多焦视网膜电图电信号的采集方式及应用m序列和互相关分离提取各个刺激部位反应的技术。根据各部位反应获得的视网膜功能地形图,为临床早期发现局部视网膜功能损害提供客观的评价工具。     

Genome-Wide Investigation of Multifocal and Unifocal Prostate Cancer—Are They Genetically Different?

Prostate cancer is widely observed to be biologically heterogeneous. Its heterogeneity is manifested histologically as multifocal prostate cancer, which is observed more frequently than unifocal prostate cancer. The clinical and prognostic significance of either focal cancer type is not fully established. To investigate prostate cancer heterogeneity, the genetic profiles of multifocal and unifocal prostate cancers were compared. Here, we report observations deduced from tumor-tumor comparison of copy number alteration data of both focal categories. Forty-one fresh frozen prostate cancer foci from 14 multifocal prostate cancers and eight unifocal prostate cancers were subjected to copy number variation analysis with the Affymetrix SNP 6.0 microarray tool. With the investigated cases, tumors obtained from a single prostate exhibited different genetic profiles of variable degrees. Further comparison identified no distinct genetic pattern or signatures specific to multifocal or unifocal prostate cancer. Our findings suggest that samples obtained from multiple sites of a single unifocal prostate cancer show as much genetic heterogeneity and variability as separate tumors obtained from a single multifocal prostate cancer.     

Space-multiplexed multifocal nonlinear microscopy

Standard forms of nonlinear microscopy rely on single beam scanning, but the usually weaker signal and the need to image in real-time call for parallelization of the image formation. Since the nonlinear susceptibilities necessitate a comparatively large illumination power, with current laser systems the brightness or field of view of any parallelized nonlinear microscope is limited by the brightness of the laser. For example, by producing an array of high aperture foci, multifocal multiphoton microscopy (MMM) provides real-time, light-efficient three-dimensional fluorescence imaging at high-resolution. The available power limits the degree of parallelization and hence codetermines the field of view. As the utilization of all the laser power is imperative, the focal intensity can be adjusted only through altering the number of foci. This compromises to some extent the flexibility to adjust the focal intensity to benign and effective levels. Here we introduce space-multiplexing (SMX) as a novel option in parallelized nonlinear microscopy, which enables an improved exploitation of the total laser power and facilitates changing the intensity levels in selected regions, without attenuating the total laser power. The basic idea of SMX is to overlap arrays of slightly offset coherent focal fields whose interference modulates the intensity across the sample. For a given degree of parallelization and power, SMX increases the two- and three-photon excited signal of parallelized nonlinear microscopy by a factor of up to 1.5 and 2.5, respectively. To some extent, sensitive regions may be spared out, whereas in regions with weaker nonlinear susceptibilities the intensity is increased. SMX is relevant to all modes of nonlinear microscopy, including parallelized second- and third-harmonic imaging, coherent anti-Stokes Raman scattering, and widefield multiphoton excitation.     

Structure–Function Relationship of Retinal Ganglion Cells in Multiple Sclerosis

The retinal ganglion cells (RGC) may be considered an easily accessible pathophysiological site of degenerative processes in neurological diseases, such as the RGC damage detectable in multiple sclerosis (MS) patients with (HON) and without a history of optic neuritis (NON). We aimed to assess and interrelate RGC functional and structural damage in different retinal layers and retinal sites. We included 12 NON patients, 11 HON patients and 14 healthy controls for cross-sectional multifocal pattern electroretinography (mfPERG) and optical coherence tomography (OCT) measurements. Amplitude and peak times of the mfPERG were assessed. Macula and disc OCT scans were acquired to determine macular retinal layer and peripapillary retinal nerve fiber layer (pRNFL) thickness. In both HON and NON patients the foveal N2 amplitude of the mfPERG was reduced compared to controls. The parafoveal P1 peak time was significantly reduced in HON only. For OCT, parafoveal (pfGCL) and perifoveal (pGCL) ganglion cell layer thicknesses were decreased in HON vs. controls, while pRNFL in the papillomacular bundle sector (PMB) showed reductions in both NON and HON. As the mfPERG derived N2 originates from RGC axons, these findings suggest foveal axonal dysfunction not only in HON, but also in NON patients.     

变焦镜头结构形式的最佳选择方法

从几个方面介绍了对结构型式的选择考虑方法,具体地分析了每种方法对结构设计产生的不同效果。为此在设计之前要求考虑各种因素,解决光学系统像质好与结构简单化、外形尺寸要小之间的矛盾,最终选择最佳设计方案,使之达到所要求的目的。     

糖尿病黄斑水肿分级及其多焦视网膜电图异常改变的研究

目的：探讨糖尿病黄斑水肿（DME）分级及其多焦视网膜电图P1波异常改变。方法：糖尿病眼OCT扫描后进行DME分级,后行多焦视网膜电图（mfERG）检测,分析一阶反应P1波振幅密度和潜伏期随DME进展的变化关系。结果：DME早期已有P1波振幅密度的降低（P〈0.05）,随后出现潜伏期延长（P〈0.05）。结论：随DME进...     

MGMT-Methylation in Non-Neoplastic Diseases of the Central Nervous System

Quantifying O⁶-methylguanine-DNA methyltransferase (MGMT) promoter methylation plays an essential role in assessing the potential efficacy of alkylating agents in the chemotherapy of malignant gliomas. MGMT promoter methylation is considered to be a characteristic of subgroups of certain malignancies but has also been described in various peripheral inflammatory diseases. However, MGMT promoter methylation levels have not yet been investigated in non-neoplastic brain diseases. This study demonstrates for the first time that one can indeed detect slightly enhanced MGMT promoter methylation in individual cases of inflammatory demyelinating CNS diseases such as multiple sclerosis and progressive multifocal leucencephalopathy (PML), as well as in other demyelinating diseases such as central pontine and exptrapontine myelinolysis, and diseases with myelin damage such as Wallerian degeneration. In this context, we identified a reduction in the expression of the demethylase TET1 as a possible cause for the enhanced MGMT promoter methylation. Hence, we show for the first time that MGMT hypermethylation occurs in chronic diseases that are not strictly associated to distinct pathogens, oncogenic viruses or neoplasms but that lead to damage of the myelin sheath in various ways. While this gives new insights into epigenetic and pathophysiological processes involved in de- and remyelination, which might offer new therapeutic opportunities for demyelinating diseases in the future, it also reduces the specificity of MGMT hypermethylation as a tumor biomarker.     

The Role of Extracellular Vesicles in Demyelination of the Central Nervous System

It is being increasingly demonstrated that extracellular vesicles (EVs) are deeply involved in the physiology of the central nervous system (CNS). Processes such as synaptic activity, neuron-glia communication, myelination and immune response are modulated by EVs. Likewise, these vesicles may participate in many pathological processes, both as triggers of disease or, on the contrary, as mechanisms of repair. EVs play relevant roles in neurodegenerative disorders such as Alzheimer’s or Parkinson’s diseases, in viral infections of the CNS and in demyelinating pathologies such as multiple sclerosis (MS). This review describes the involvement of these membrane vesicles in major demyelinating diseases, including MS, neuromyelitis optica, progressive multifocal leukoencephalopathy and demyelination associated to herpesviruses.     

基于小波变换的多焦视觉电生理信号去噪研究

多焦视觉电生理信号具有较强的随机性和背景噪声,且又属于非线性、非平稳的微弱信号,用Fourier变换来进行去噪处理其效果不是特别理想.小波变换(WT)具有优良的时间-频域分析和多分辨分析特性,可以用来处理非平稳随机信号,能获得更多的、具有诊断价值的信息,因此WT成为多焦视觉电生理信号的一种可行有效的去噪处理方法.文章基...     

特发性黄斑前膜手术疗效分析

目的探讨特发性黄斑前膜手术治疗的效果及安全性。方法特发性黄斑前膜21眼行玻璃体手术,术后1、3、6及12月,进行视力、光学相干断层成像(opticalcoherencetomography,OCT)、多焦视网膜电流图(multifocalelectroretinogram,MERG)检查,应用SPSS11.5软件对结果进行统计学分析。结果(1)术后12月视力改善2行以上90%(19/21),视物变形改善81%(17/21),与术前差异有显著性(P<0.05);(2)OCT显示手术前视网膜平均厚度496.76±93ìm,术后12月平均厚度(176.09±27.97)ìm,与术前差异有显著性(P<0.05);(3)术前MERG地形图可见中心峰下降,一级反应1、2、环P1波反应密度明显降低,术后12月MERG中央峰逐渐恢复,1、2、环P1波反应密度明显升高,与术前差异有显著性(P<0.05)。结论玻璃体手术治疗特发性黄斑前膜疗效可靠,视力、OCT及MERG可以较好地进行疗效客观评价。