翼状胬肉术后的角膜地形图改变

目的 评价翼状胬肉术前术后的角膜屈光状态及其与术前胬肉大小的关系，探讨胬肉手术的时机与必要性。方法 对29例(32只眼)翼状胬肉患者进行胬肉侵入角膜的长度测量，并于术前术后行角膜地形图检测，以资对比。结果 32只眼均有程度不同的顺规散光，其大小与翼状胬肉侵入角膜的长度有关。手术显著降低了角膜散光，提高了角膜平均屈光力。手术导致的角膜散光变化、角膜平均屈光力变化和术前胬肉大小显著相关。结论 翼状胬肉的生长和手术切除对角膜的屈光状况有显著影响，胬肉越大，这种影响就越大。当胬肉较大时，角膜地形图的改变可能包括一部分假象。     

Frontal versus transcorneal stimulation to induce maximal electroshock seizures or kindling in mice and rats

Frontal stimulation, i.e. electrical stimulation where electrodes are pressed on the skin of the intact frontal skull of mice or rats, may represent a more humane alternative to the widely used transcorneal stimulation to induce electroshock seizures. The aim of this work was to directly compare transcorneal and frontal stimulation in eliciting maximal electroshock-induced seizures (MES) in mice and the anticonvulsant effect of carbamazepine (CBZ) and phenytoin (PHT) on thus produced seizures. In addition, we stimulated mice and rats repeatedly via transcorneal and frontal electrodes to see whether kindling is produced by this procedure. Two electroshock tests were used in mice, i.e. maximal electroshock seizure threshold (MEST) test and MES generated by supramaximal stimulation (50 mA). Frontal stimulation resulted in lower convulsive threshold than in the case of corneal stimulation. Both CBZ and PHT produced dose-dependent increases in seizure threshold for both sites of stimulation, i.e. transcorneal and frontal. As regards type of electrodes, higher doses of PHT were required to increase seizure threshold in the case of frontal than transcorneal stimulation. Supramaximal stimulation (50 mA) yielded comparable ED₅₀ values regardless of the site of stimulation. Furthermore, once-daily stimulation of mice, regardless of the placement of electrodes, did not induce any changes in convulsive threshold. We also attempted to kindle mice and rats via corneal and frontal electrodes by repetitive electrical stimulation using currents which initially did not produce generalized clonic seizures. Mice were stimulated once daily for 2 s with 3 mA (corneal electrodes) or 2 mA (frontal electrodes) and rats were stimulated twice daily for 4 s at 8 mA (corneal electrodes) or 5 mA (frontal electrodes). With corneal stimulation in rats there was a clear progression of kindling development which was not the same in nature when compared with corneally-stimulated mice. Frontal stimulation did not produce kindling. Moreover, corneal stimulation was better tolerated by rats, while in mice high mortality was seen after either method of current delivery. Our data indicate that frontal electrodes can be used as an alternative to transcorneal stimulation to produce MES by supramaximal or threshold current intensities as screening procedures in antiepileptic drug (AED) development. Nevertheless, this type of stimulation cannot be used to produce minimal electroshock seizures and seems not to be useful to produce kindling in rats and mice.     

Susceptibility of corneal allografts and xenografts to antibody-mediated rejection

The effects of passive transfer of antisera containing cytotoxic antibodies to allo- and xenoantigens on survival of corneal allografts and xenografts were evaluated in experimental models. Corneas from allogeneic B10 or xenogeneic rat Lewis donors were grafted orthotopically into BALB/c mice. Recipient mice were treated with donor-specific antisera administered at the period of grafting or at 2 weeks after transplantation. Rejection was determined by the severity of corneal opacity using a standard scoring system. Treatment of graft recipients with donor-specific antisera accelerated the onset of graft rejection and significantly shortened survival times of both corneal allografts and xenografts. Corneal xenografts, which had been accepted after treatment with anti-CD4 monoclonal antibody, were acutely rejected by the passive transfer of antiserum against xenoantigens. The results suggest that corneal grafts are vulnerable to antibody-dependent immunity and that cytotoxic antibodies against graft donor antigens can mediate rejection of both corneal allografts and xenografts.     

生物工程活性角膜基质的研制及相容性研究

研究生物工程活性角膜的生物相容性，为进一步临床应用提供理论基础。猪角膜基质脱细胞并去除免疫源性物质形成网状半透明生物材料，将培养的角膜基质细胞与生物材料复合构建生物工程活性角膜基质。对复合物进行倒置显微镜和扫描电镜检测细胞附着情况及材料的细胞相容性；将活性角膜基质移植入新西兰兔角膜囊袋内．细胞用BrdU标记检测在体内移植过程中的存活及转归，不同时间观察角膜的生物相容性及改建情况。结果显示脱细胞基质材料的细胞相容性较好，细胞种植后可存活、黏附并增殖；移植区细胞可有BrdU阳性着色，4周后角膜开始透明，8周后角膜改建基本完成。     

Sodium channels in ocular epithelia

Voltage-gated, tetrodotoxin(TTX)-blockable sodium channels are found in most excitable cells and are the primary contributors to action potentials generated by many of these cells. To date, there has only been one report of a non-cultured vertebrate epithelial cell type containing TTX-blockable Na⁺ channels: rabbit non-pigmented ciliary body epithelial cells [Cilluffo MC et al. (1991) Invest Opthalmol Vis Sci 32:1619–1629], and three reports of cultured epithelial cells containing TTX-blockable Na⁺ channels: rabbit non-pigmented and pigmented ciliary body epithelium [Ciluffo MC et al. (1991) Invest Opthalmol Vis Sci 32:1619–1629; Fain GL, Farahbakhsh (1989) J Physiol (Lond) 417:83–103] and human lens epithelium [Cooper K et al. (1990) J Membr Biol 117:285–298]. We report here the presence of sodium currents in two different non-cultured, freshly dissociated transporting epithelial cell types: the rabbit corneal endothelium and the frog lens epithelium. We also report the occurrence of sodium currents in six additional cultured ocular epithelial cell types from three different species. These currents have a current/voltage (I/V) relationship consistent with traditional voltage-gated Na⁺ currents, are quinidine- and TTX-blockable (of the low-affinity TTX-sensitive type), and disappear following bath substitution of Na⁺ with Cs⁺ or K⁺.     

糖尿病对白内障超声乳化术后角膜知觉改变的影响

目的 探讨糖尿病对白内障超声乳化吸除术后角膜知觉改变的影响。方法 选择行白内障超声乳化吸除手术的糖尿病患者42例（42只眼）,不伴有糖尿病的患者46例（46只眼）,分别观察白内障超声乳化手术前、术后1天、术后1周、术后1个月、术后3个月、术后6个月的角膜知觉。结果 与术前相比,糖尿病白内障患者角膜知觉在术后1天、术后1周、术后1个月、术后3个月明显降低,差异有显著性,术后6个月接近术前水平;不伴糖尿病的白内障患者角膜知觉在术后1天、术后1周、术后1个月降低,差异有显著性,术后3个月接近术前水平。两组患者术前角膜知觉比较,差异有显著性;术后角膜知觉最大降幅比较,差异有显著性。结论 糖尿病可降低患者的角膜知觉,增大白内障手术后角膜知觉的降幅,延长角膜知觉的恢复时间。     

青光眼滤过术后透明角膜切口白内障超声乳化摘除人工晶体植入术

介绍经透明角膜切口的青光眼滤过术后白内障超声乳化摘除人工晶体植入的方法及疗效。方法：对１８例１８眼施行手术,上方透明角膜内１ｍｍ处做３．２ｍｍ切口,。超声乳化白内障摘除后扩大切口中至５．５－６ｍｍ,植入人工晶体。结果１８眼术后视力全部提高,术中术后无严重并发症。     

板层角膜移植治疗翼状胬肉及角膜皮样瘤

为观察板层角膜移植治疗翼状胬肉及角膜皮样瘤的疗效,我们对17例(17只眼)翼状胬肉患者及5例(5只眼)角膜皮样瘤患者进行了板层角膜移植。术后随访1～4年。翼状胬肉组和角膜皮样瘤组植片透明率分别为82.4%及100%。翼状胬肉组排斥反应发生率为17.6%,角膜皮样瘤组无一例发生排斥反应。所有病例角膜中央厚度手术前后差异无显著性意义(P>0.05)。两组病例术后角膜散光均较术前降低,差异均有显著性意义(P<0.05)。两组病例术后视力均有不同程度提高。翼状胬肉组术后复发率为11.8%。结果表明板层角膜移植可使角膜完整、植片透明、减少散光、提高视力并降低术后翼状胬肉的复发率,是一种理想的治疗方法,值得推广。     

Endothelial cell transplantation and growth behavior of the human corneal endothelium

Background: The human corneal endothelium has a limited proliferative capacity in vivo. Until now it has only been possible to replace damaged endothelium by transplantation of a donor cornea. After establishing methods for the isolation and in vitro cultivation of human corneal endothelial cells, transplantation of these cells my be an alternative therapeutic option. Materials and methods: In this review methods for the in vitro cultivation of human corneal endothelial cells and their transplantation on the Descemet membrane of donor corneas are described. Results: In vitro proliferation of human adult corneal endothelial cells was achieved by the development of defined cell culture conditions, including supplementation of culture medium with specified growth factors and substances. Dependent on the culture conditions, as well as independent of them, in vitro cultured endothelial cells showed phenotypic changes and different proliferative behavior. Thus, molecular biological examinations revealed a different expression pattern of growth factor receptors in fibroblast-like endothelial cells (dedifferentiated) compared to typical endothelial cells (differentiated). Moreover, the proliferative capacity of the cells differed, dependent on their corneal location. Cells isolated from the peripheral part of donor corneas have a higher proliferative capacity than cells obtained from the central part. The propagation of corneal endothelial cells in vitro offered the possibility of their transplantation on donor corneas in an in vitro model. After transplantation, these cells formed a monolayer whose morphology and cell density depended on the differentiation of the cells. DNA synthesis was predominantly detectable in cells of the corneal periphery. Conclusions: Our findings are the basis of the following hypothesis: the periphery of the cornea represents a regenerative zone of the corneal endothelium. The fact that early after transplantation corneal endothelial cells form a monolayer on the natural extracellular matrix (ECM), which shows contact inhibition, suggests that inhibitory factors are released by the Descemet membrane that influence the proliferation of the cells. Further studies on the regulation of the proliferation and differentiation of human corneal endothelial cells in vitro and after transplantation might offer the possibility to establish a selective procedure for the treatment of corneal endothelial cell loss in the near future.      

外伤角膜瘢痕无晶状体眼戴角膜接触镜后的角膜地形图改变

目的 探讨外伤性角膜瘢痕无晶状体眼戴硬性透气性接触镜前,后角膜表面的改变。方法 对戴该镜者１７眼及对照组（不戴镜）１２眼,在戴镜前后进行角膜地形图检测。结果 戴镜后平均８．４月,角膜散光减少（Ｐ〈０．０１）,角膜表面变得比较规则（Ｐ〈０．０５）,角膜表面的屈光度有变得相对比较平均的趋势。结论 戴硬性透气性角膜接触镜能使角膜瘢痕所致角膜散光减少,角膜表面变得较为规则。