Biochemical and immunological properties of 34kDa EDTA-extractable protein (EEP34k)

It has been reported that the 34kDa protein of EDTA-extractable protein (EEP34k) cross-reacted with lipocortin antisera. The lipocortins are a family of proteins that have been reported to inhibit phospholipase A2. Previously, we purified two proteins from EEP34k by anion-exchange chromatography, and referred to them as 34k (A) and 34k (B). On Western-blot analysis, two proteins showed cross-reactivity to both lipocortin I and lipocortin II. In this study, four proteins (34k (A)1, 34k (A)2, 34k (B)1, 34k (B)2) were isolated from 34k (A) and 34k (B), on a cation-exchanged chromatography. By peptide mapping, immunological analysis and SDS/PAGE, we confirmed that 34k (A)1 and 34k (B)2 were identified proteins and these were called lipocortin I, and that 34k (A)2 was lipocortin II. It is concluded that at least two lipocortins, I and II are present in EEP34k. We also observed the presence of phospholipase A2 inhibitory activity in both 34k (A) and 34k (B).     

Functional similarities between polarization vision and color vision

Consideration o the similarities between color vision (CV) and polarization vision (PV) leads to improved theoretical understanding of PV and to suggestions for new kinds of behavioral and electrophysiological experiments involving partially polarized light. We propose that angle and degree of polarization as parameters for a PV system are analogous to dominant wavelength and purity as parameters for a CV system. Although three linearly independent receptors must cooperate to determine polarizational angle independent of both degree and intensity, a PV system based on only two receptors is not polarization-blind but is characterized by neutral points and confusion states of polarization if the eye fixates.     

Phenotypic similarities between Stargardt's flavimaculatus and pattern dystrophies

Some heredomacular diseases share ophthalmoscopic and morphologic similarities despite being nosologically distinct. In part, this may arise from pathologic reaction patterns such as lipopigment accumulation and drusen deposition which are common to a variety of disorders of the photoreceptor—retinal pigment epithelium—Bruch's membrane complex. Two of these disorders, Stargardt's flavimaculatus and the pattern dystrophies of the retinal pigment epithelium may be especially difficult to differentiate clinically since they are characterised by both a similar ophthalmoscopic appearance and considerable inter and intrafamilial variation in their expression. Stargardt's flavimaculatus may, however, be distinguished from the retinal pigment epithelial pattern dystrophies by certain clinical and morphological features that are outlined below.     

Phenotypic similarities between Stargardt's flavimaculatus and pattern dystrophies.

Some heredomacular diseases share ophthalmoscopic and morphologic similarities despite being nosologically distinct. In part, this may arise from pathologic reaction patterns such as lipopigment accumulation and drusen deposition which are common to a variety of disorders of the photoreceptor--retinal pigment epithelium--Bruch's membrane complex. Two of these disorders, Stargardt's flavimaculatus and the pattern dystrophies of the retinal pigment epithelium may be especially difficult to differentiate clinically since they are characterised by both a similar ophthalmoscopic appearance and considerable inter and intrafamilial variation in their expression. Stargardt's flavimaculatus may, however, be distinguished from the retinal pigment epithelial pattern dystrophies by certain clinical and morphological features that are outlined below.     

Biochemical and immunological properties of EEP 32 kd protein

EDTA-extractable protein (EEP) is a major extrinsic protein of lens membrane. EEP is composed of two major polypeptides on SDS-PAGE with apparent molecular weights of 32 kilodaltons (kd) and 34 kd. Recently it has been reported that the 34 kd protein of the EEP cross-reacted with the antibody prepared against lipocortin, an inhibitor of phospholipase A2. We have purified and characterized the 32 kd protein of the EEP (EEP 32). Crude EEP of bovine lens was applied to a Q-Sepharose column and eluted with a linear gradient system composed of 0-0.7 M NaCl. The EEP 32 was discreted at salt concentrations of approximately 0.1-0.25 M (EEP 32-A) and 0.35-0.4 M (EEP 32-B). Both EEP 32-A and EEP 32-B interact with phospholipid and F-actin in a Ca2+-dependent manner as lipocortin. Furthermore, the EEP 32-A, a major component of the EEP 32 purified by hydroxyapatite chromatography and gel filtration, inhibited phospholipase A2 activity more than lipocortin. On Western blot analysis, the 32 kd lipocortin-like protein of human placenta showed cross-reactivity to EEP 32-B, but not EEP 32-A. These results suggest that EEP 32 contains two lipocortin-like proteins differing in antigenicity and isoelectric points.     

Electrophysiological similarities between two eyes with X-linked recessive retinoschisis

Electroretinograms (ERG) and electro-oculograms (EOG) were studied in 88 eyes of 44 male patients with X-linked recessive retinoschisis. Differences of fundus appearance, ERG, and EOG between the eyes of each patient were analyzed. Fundus abnormalities were symmetrical in 77.3% of the cases. The amplitude of the ERG a-wave was normal in 26.1% and was abnormally low in 73.9%. The amplitude of the b-wave was below normal in all eyes; thus a small b-wave/a-wave ratio, which is characteristic of X-linked recessive retinoschisis, was observed in every case. The light peak to dark trough (LP/DT) ratio of the EOG was normal in 90.8% of the cases. The relative electrophysiological differences between the two eyes were calculated and showed that a-wave amplitude was not different between eyes in 75.0% of the cases; b-wave amplitude was not different in 77.3% of the cases; b-wave/a-wave ratio was symmetrical in 93.2% of the cases; and the LP/DT ratio was consistent between eyes in 86.8% of the cases. These results suggest that in most cases of X-linked recessive retinoschisis the fundus appearance, ERG, and EOG are similarly affected in both eyes of the patient.     

Retinal sensitivity in hereditary retinal degeneration in Abyssinian cats: electrophysiological similarities between man and cat.

The functional and electrophysiological similarities in the changes in the electroretinogram (ERG) of man and cat affected by hereditary retinal degenerative disease were studied. The results of a series of log intensity-amplitude studies in a group of young affected Abyssinian cats were fitted to the Naka-Rushton relationship by means of a mathematical package on the University of London mainframe. The analysis showed that the amplitude of the maximum dark-adapted b-wave was significantly reduced by the end of the period studied but that the value of k, a variable inversely equivalent to retinal sensitivity, was only slightly reduced by the retinal degenerative process. The electrophysiological findings thus are similar to those found in cases of human diffuse dominantly inherited retinitis pigmentosa.     

Correlation between microRNA-34a levels and lens opacity severity in age-related cataracts

Purpose

MicroRNA 34a (miR-34a) is involved in regulating tissue senescence. However, the role of miR-34a in age-related cataracts is unclear. In this study, we evaluated the correlations among the severity of lens opacity, patient age, and miR-34a expression level in the lens epithelium of age-related cataracts for clarifying the role of miR-34a in the lens senescence.

Methods

This study was carried as a case control study in the Department of Ophthalmology, Taipei Veterans General Hospital, Taiwan. We recorded age of each patient at the time of their cataract surgery and information regarding lens opacity according to a modified version of the Lens Opacities Classification System III. Correlations among age, lens opacity, and miR-34a expression levels were evaluated.

Results

This study evaluated 110 patients with a mean age of 73.19 years (SD±10.2). Older patients had higher nuclear cataract (NC), cortical (C), and posterior subcapsular cataract (P) scores (one-way analysis of variance (ANOVA), P<0.05). miR-34a expression levels were significantly different between each age group (ANOVA post hoc Bonferroni''s test, P<0.001), and there were moderate correlations between high NC, C, and P cataract scores and high miR-34a levels (Pearson correlation coefficient; R=0.606, 0.575, and 0.515, respectively).

Conclusions

The current study demonstrated positive correlations between high miR-34a levels and high lens opacity severity in NC, C, or P cataracts. These results suggest that miR-34a expression has a role in lens senescence.     

值得进一步深入研究的眼底病热点:息肉样脉络膜血管病变与老年性黄斑变性的异同

息肉样脉络膜血管病变(PCV)是以视网膜下出血、视网膜色素上皮脱离和神经上皮脱离为特征的渗出性黄斑病变,占我国新生血管性老年性黄斑变性(AMD)患者的33.5％.吲哚青绿血管造影检查发现脉络膜来源的单个或多个结节样强荧光为当前PCV诊断的金标准.组织病理学检查显示脉络膜毛细血管透明样变,与动脉硬化表现相似;基因研究目前尚未发现PCV与AMD的区别;环境因素显示高血压与PCV的相关性超过与AMD的相关.PCV与AMD是不同的基因型还是相同的基因产生不同的表型,以及两种疾病发病机制的异同均有待进一步的研究.     

Retinal ischemia and reperfusion causes capillary degeneration: similarities to diabetes

PURPOSE: Retinal neurons and vasculature interact with each other under normal conditions, and occlusion of the retinal vasculature can result in damage to retinal neurons. Whether damage to the neural retina will damage the vasculature, however, is less clear. This study was conducted to explore the relationship between vascular and nonvascular cells of the retina. The response of the retinal vasculature to an injury (ischemia and reperfusion; I/R) that is known to cause neuronal degeneration was studied. METHODS: I/R injury to the retinas was induced in Lewis rats and C57BL/6J mice by elevating intraocular pressure (IOP), and reperfusion was established immediately afterward. Some rats were pretreated with aminoguanidine (AMG, 50 mg/Kg BW in drinking water) before the procedure. Poly(ADP-ribose) polymerase (PARP) activity and expression of inducible nitric oxide synthase (iNOS), and cycloxygenase-2 (COX-2) were measured by Western blot analysis, and levels of TNF-alpha and intercellular adhesion molecule (ICAM)-1 mRNA were measured by qPCR at 2 and 7 days after the procedure. Also at 2 and 7 days after the I/R injury, apoptosis of retinal neural cells (demonstrated by TUNEL assay), density of cells in the ganglion cell layer, and thickness of retinas were quantitated, and the number of TUNEL-positive capillary cells and degenerated capillaries were assessed. Retinal neurodegeneration and capillary degeneration were also examined in C57BL/6J mice 2, 5, 8, and 14 days after I/R injury. RESULTS: As expected, loss of cells in the retinal ganglion cell layer was apparent 2 days after I/R injury in the rat and mouse models. In contrast, the retinal vasculature had essentially no pathology at this time in either model. Surprisingly, the number of degenerated capillaries increased greatly by 7 to 8 days after the injury. Administration of aminoguanidine significantly inhibited the I/R-induced capillary degeneration as well as neurodegeneration in the rat model. Retinal I/R caused increased PARP activity (detected by poly(ADP-ribosy)lated proteins), as well as upregulation of iNOS, COX-2, TNF-alpha, and ICAM-1 levels in rats, consistent with an inflammatory process. CONCLUSIONS: Capillary degeneration is an unrecognized component of acutely elevated IOP and develops only after neurodegeneration is severe. Thus, this finding raises the possibility that damage to the neural retina contributes to capillary degeneration. Aminoguanidine, a nonspecific inhibitor of iNOS, inhibited I/R-induced degeneration of both neuronal and vascular cells of the retina. The model of retinal ischemia and reperfusion will be a useful tool for investigating the relationship between neuronal damage and vascular damage in glaucoma and other diseases such as diabetic retinopathy.     

脉络膜与近视相关研究进展

随着社会的发展和人民生活方式的不断变化,近视已成为影响我国公共健康的主要问题之一。近年来,脉络膜在调节眼球生长和近视发展中的重要作用备受关注。研究发现,在近视发生发展过程中,脉络膜厚度显著变薄并伴有血流灌注减少,进一步引起视网膜和巩膜局部缺氧,促进眼轴延长并加速近视发展;脉络膜的厚度和血流或许可作为近视的早期预测因子。本文即对相关研究进展进行综述。     

抑郁症与干眼关系研究进展

干眼因其发病率较高成为眼科最常见的疾病之一。ＷＨＯ预计抑郁症到２０２０年将成为全球第二大疾病负担源。干眼长期不适症状降低眼部相关生活质量,可能对患者认知过程、心理健康造成影响,而抑郁症降低患者感知身体不适的阈值或疼痛阈值可能加重患者感知眼部的不适症状。近年来抑郁症与干眼的关系研究倍受关注。本文主要通过综述抑郁症与干眼的诊断、两者关系及共同化学基础,为早期识别、早期防治、减少不良事件的发生提供重要的参考资料。     

水通道蛋白与年龄相关性白内障关系的研究进展

水通道蛋白(AQPs)结构的研究进一步加深了人们对于这种小分子膜蛋白对水和溶质转运的认识。迄今,在晶状体中有两种AQPs表达被报道,即AQP0和AQP1。我们主要就AQPs在晶状体的分布、功能及与白内障形成的可能关系进行讨论。     

CD34在翼状胬肉中表达的意义

目的研究翼状胬肉组织中CD34的表达及意义。方法对50例手术切除的翼状胬肉标本行苏木精-伊红染色、过碘酸希夫染色，并进行形态学、免疫组织化学研究和免疫荧光共聚焦显微镜下观察CD34、波形蛋白（VIM）、血管内皮生长因子（VEGF）在翼状胬肉中的表达。结果在翼状胬肉标本中，CD34在血管内皮细胞、血管周细胞以及一些散在的星形、梭形细胞中表达阳性，而在血管壁上及成熟的胶原细胞上呈阴性表达；VIM阳性表达于大部分翼状胬肉组织中；组织中部分疏松排列的网状及裂隙样、管样区结构过碘酸希夫染色呈阳性的紫红色反应；网状区的梭形细胞VEGF阳性表达。结论翼状胬肉组织中CD34阳性细胞来源于间充质干细胞的分化。翼状胬肉除以血管发生和血管新生的方式生成血管外，血管拟态可能是另外一种供血途径。     

虹膜睫状体肿物的超声生物显微镜检查

目的 探讨超声生物显微镜（ultrasound biomicroscope, UBM）在虹膜睫状体肿物诊断治疗中的应用价值。 方法 对34例怀疑虹膜睫状体肿物的患者的35只患眼以UBM（Humphrey 840型，扫描频率50 MHz，扫描深度范围5 mm×5 mm）检查，17例行眼科专用B型超声或彩色超声检查,5例行CT检查，并对21只患眼手术切除的病变组织作病理组织学检查。 结果 35只患眼虹膜睫状体肿物可被UBM发现并确定其起始部位。其中UBM诊断前房虹膜囊肿6只眼,病理诊断虹膜植入性囊肿3只眼;UBM诊断虹膜后囊肿13例14只眼,病理诊断虹膜后囊肿3只眼;UBM诊断虹膜睫状体肿物15只眼,病理诊断睫状体黑瘤7只眼，虹膜睫状体转移癌4只眼，睫状体神经鞘瘤1只眼，平滑肌瘤1只眼，睫状体黑色素细胞瘤1只眼，色素上皮腺癌1只眼。 结论 UBM检查能发现虹膜睫状体部位的肿瘤并提供其大小、范围和结构信息，有助于了解病变的位置、性质，有助于手术设计和肿物的完全切除。 (中华眼底病杂志, 2002, 18: 128-130)