小白鼠眼的形态发生的研究

从小白发产胚胎第８ｄ形成视泡开始到发育为成体的眼为止，详细观察和描述了其眼的形态发育变化，实验以视网膜、晶体和角膜的发育为主。结果表明：视网膜的发育从胚胎第８ｄ视泡出现开始，在胚胎第９．５ｄ分化为２层，第１１．５ｄ分化为４层，刚出生时分化为６层，成年已分化完全，具完整的１０层结构；晶体的形态发生经历了晶体板（第９．５ｄ）、晶体凹（第１０ｄ）、晶体囊（第１０．５ｄ）、初级晶体纤维（第１１．５ｄ）及次     

角膜生物力学特性研究进展

 角膜的光学功能与其形态结构紧密相联,角膜形态的异常可导致近视、远视、圆锥角膜等眼部疾病。细致研究角膜的力学特性,建立有临床用途的生物力学模型已成为一个重要研究领域。本文以首都医科大学眼生物力学研究团队的研究工作为基础,综述在角膜力学特性研究中的实验测试方法和本构参数获取方法等方面的进展。     

草原沙蜥顶眼组织结构的半薄切片观察

草原沙蜥顶眼的角膜是由位于顶眼部位的皮肤特化形成，皮肤细胞色素消失，外表面的立方形细胞变为扁平细胞，其下的基质逐渐增厚，纤维增多，透明成角膜。晶状体与角膜紧密相贴，由交错排列的的几层柱状细胞组成，视网膜和晶状体相连，由感光细胞，色素细胞和神经节细胞组成，在由晶状体和视网膜围成的眼腔中，有玻璃体样结构分布，偶见有散在的细胞位于玻璃体样结构中。     

Retention of topical liposomal formulations on the cornea

Summary The ability of liposomes composed of different kinds of phospholipid materials to adhere to the surface of the cornea was studied in the rabbit. The liposomes were labelled with tracer amounts of an I¹²⁵-labelled phosphatidylethanolamine derivative and were instilled in 10 l drops onto the cornea. The retention of radioactivity was monitored. The results show that liposomes containing positively charged phospholipids are better retained than an albumin control. Thus, it may be possible to develop a drug delivery, liposome system which would permit long-term sustained release of ophthalmic drugs onto the cornea.     

激光原位角膜磨镶术生物的力学特性

依据角膜的生物力学特点和结构特性,构造了角膜几何模型,以可视化模拟为原则、以有限元技术为基本方法,对激光原位角膜磨镶术进行了计算机模拟计算分析.探讨了角膜基质切削深度、切削光区直径以及眼内压值等重要手术参数对手术效果的影响.结果表明,眼压较大而角膜较薄的人不宜做LASIK手术,切削光区直径较小的矫正效果较好;采用现代工程分析知识及相关软件对激光原位角膜磨镶术生物力学特性进行分析,其结果对手术有很大的实际意义和一定的参考价值.     

不同方法处理的角膜脱细胞基质组织学生物特性的比较

目的:比较不同的角膜脱细胞基质方法,旨在选择最适合的脱细胞基质方法,制备成为组织工程角膜支架材料和角膜替代物的脱细胞基质.方法:分别用胰酶-曲拉通法、SDS-戊二醛法、胰酶-冷冻法等方法对角膜进行脱细胞处理,并对脱细胞彻底的基质进行力学特性、透光率的分析.结果:用胰酶-冷冻法获得的兔角膜全层和分层基质脱细胞最彻底,基质的结构未见明显破坏,脱细胞基质在生物力学特性上与正常角膜接近,透光率低于新鲜角膜.结论:用胰酶-冷冻法获得的脱细胞基质与自然角膜接近,可作为组织工程角膜支架材料和角膜替代物.     

IL-1β regulates the mouse Fas ligand expression in corneal endothelial cells

Constitutively expressed Fas ligand (FasL) in several distinct epithelial cell types appears to protect tissues by inducing apoptosis of Fas immune cells during inflammatory reactions. To study the rela-tionship of FasL and inflammation process in cornea,we examined the effects of inflammatory cytokine IL-1β on the FasL production,expression and cytotoxic function in corneal endothelial cells. In this paper,we demonstrate that IL-1β inhibits the FasL production and expression in corneal endothelial cells. The promoter activities of FasL in these cells are reduced by IL-1β in a dose-dependent manner. Finally,we also find that IL-1β block the cytotoxic effects of FasL derived from corneal endothelial cells to the Fas target cells. These data support the view that FasL derived from corneal endothelial cells modulate inflammation within cornea.     

角膜组织工程支架壳聚糖-胶原复合膜的性能

制备了壳聚糖-胶原角膜组织工程支架，考察了复合膜支架的光学性能、力学强度、结晶性、吸水率、亲水性、微观形貌及细胞亲和性，发现支架内胶原与壳聚糖两种分子间存在较强的相互作用，且具有良好的相容性，支架表面平滑均一，内部呈现层状有序结构．壳聚糖-胶原复合膜具有优异的透光率和适宜的湿态力学强度．细胞培养实验中，人角膜缘上皮细胞能在支架上较好地粘附和增殖分化，显示复合膜支架具有良好的细胞亲和性．结果表明壳聚糖-胶原复合膜有望成为一种性能良好的角膜组织工程支架．     

眼角膜在冻干过程中的传热传质模型

通过对角膜干燥过程的理论分析,建立了能真实描述角膜干燥过程传热传质的数学模型。采用ANSYS有限元计算软件对角膜的冻干过程进行模拟计算,得出如下结果：冻干室内温度约-10℃,压强维持在50Pa左右时,角膜双面冻干所需时间为170min。采用移动网格来追踪升华界面上各节点的参数值,提高了本模型的计算精度,计算结果直观可靠,物理意义明确。     

Dynamical simulation of cornea deformation in laser surgery

A dynamical simulation method is presented to model the cornea deformation in surgery of laser thermokeratoplasty. The virtual cornea is constructed as a mass-spring system. The corneal surface tension is simulated by damping spring stretch between mass points on the cornea model. The aqueous humor in the eyeball is modeled as ideal gas, and the intraocular pressure is simulated by gas pressure. The coagulation force is exerted on each photocoagulation spot to demonstrate its collapse caused by the condensation of corneal soft tissue irradiated by laser. An extra viscous drag force is added to each mass point to weaken the mass point oscillation. The use of the effective time-corrected Verlet integral method brings about flowing and stable dynamic simulation procedures. The simulation results show that, comparing to the undeformed model, the curvature of the region between the optical center and photocoagulation spot increases obviously. Moreover, the shape of the deformed virtual cornea is much similar to that of the real cornea after surgery.