31P solid-state NMR based monitoring of permeation of cell penetrating peptides into skin

The main objective of the current study was to investigate penetration of cell penetrating peptides (CPPs: TAT, R₈, R₁₁, and YKA) through skin intercellular lipids using ³¹P magic angle spinning (MAS) solid-state NMR. In vitro skin permeation studies were performed on rat skin, and sections (0–60, 61–120, and 121–180 μm) were collected and analyzed for ³¹P NMR signal. The concentration-dependent shift of 0, 25, 50, 100, and 200 mg/ml of TAT on skin layers, diffusion of TAT, R₈, R₁₁, and YKA in the skin and time dependent permeation of R₁₁ was measured on various skin sections using ³¹P solid-state NMR. Further, CPPs and CPP-tagged fluorescent dye encapsulate liposomes (FLip) in skin layers were tagged using confocal microscopy. The change in ³¹P NMR chemical shift was found to depend monotonically on the amount of CPP applied on skin, with saturation behavior above 100 mg/ml CPP concentration. R₁₁ and TAT caused more shift in solid-state NMR peaks compared to other peptides. Furthermore, NMR spectra showed R₁₁ penetration up to 180 μm within 30 min. The results of the solid-state NMR study were in agreement with confocal microscopy studies. Thus, ³¹P solid-state NMR can be used to track CPP penetration into different skin layers.     

C-end rule peptides mediate neuropilin-1-dependent cell,vascular, and tissue penetration

Screening of phage libraries expressing random peptides for binding to prostate cancer cells primarily yielded peptides that had a C-terminal arginine (or rarely lysine) residue, usually in a consensus context R/KXXR/K. Phage expressing these sequences and synthetic nanoparticles coated with them bound to and were internalized into cells. The C-terminal arginine (or lysine) was essential to the activity; adding another amino acid, or even blocking the free carboxyl group of this arginine residue by amidation, eliminated the binding and internalizing activity. An internal R/KXXR/K can be exposed and switched on by a cleavage by a protease. The strict requirement for C-terminal exposure of the motif prompted us to term the phenomenon the C-end rule (CendR). Affinity chromatography showed that the CendR peptides bind to neuropilin-1 (NRP-1) on the target cells. NRP-1 is a cell-surface receptor that plays an essential role in angiogenesis, regulation of vascular permeability, and the development of the nervous system. VEGF-A165 and other ligands of NRP-1 possess a C-terminal CendR sequence that interacts with the b1 domain of NRP-1 and causes cellular internalization and vascular leakage. Our CendR peptides have similar effects, particularly when made multivalent through coupling to a particle. We also noted a unique and important activity of these peptides: penetration and transportation through tissues. The peptides were able to take payloads up to the nanoparticle size scale deep into extravascular tissue. Our observations have implications in drug delivery and penetration of tissue barriers and tumors.     

交错分步白内障摘除、人工晶状体植入联合角膜移植术的临床应用

目的:报告应用交错分步进行的小切口非超声乳化白内障摘除、人工晶状体植入联合角膜移植(以下简称三联术)的方法治疗角膜病与白内障同时存在并需行穿透性角膜移植及白内障摘除复明的患者,并评价其疗效。方法:应用三联术对21例21眼角膜病合并白内障患者行手术治疗,观察术后视力、移植角膜情况,随访时间4～9mo。结果:治疗后92%患者术后裸眼视力比术前提高,术后2wk视力>0.5者9例(43%),>0.3者10例(48%),0.1者2例(10%)。术后7～14d,21眼角膜植片全为透明,术后4～9mo植片完全透明17例,植片呈半透明3例,角膜中度混浊伴新生血管长入1例。结论:穿透性角膜移植联合交错分步的小切口非超声乳化白内障摘除、人工晶状体植入术,可以一次性解决眼前段屈光间质混浊。与传统联合术相比,三联术减少了术后并发症,使患者快速恢复术后视力,安全性高。     

Longterm follow‐up of penetrating keratoplasty for keratoconus

Purpose: This study aims to describe the current visual and refractive status of patients who underwent penetrating keratoplasty (PK) for keratoconus > 20 years ago and to report on the current status of their grafts. Methods: A total of 138 eyes in 103 patients were grafted for keratoconus between August 1968 and December 1985. Patients who had not undergone retransplantation were invited to attend a clinical examination. Forty‐eight patients (with 61 grafts) accepted the invitation and were examined. Results: The average length of time since PK was 26.9 years (standard deviation [SD] 4.2 years, range 20.8–38.0 years, n = 61). The average graft age at examination was 82.1 years (SD 19.9 years, range 41–115 years). A total of 80% (49 of 61 grafts) of the examined eyes had a clear graft and 46% (28 of 61 eyes) had best spectacle‐corrected visual acuity (BSCVA) ≥ 0.5. The mean endothelial cell density per mm² was 894 (SD 4.6, range 470–1775). The mean central corneal thickness of the clear grafts was 0.565 mm (SD 0.048 mm). Conclusions: Penetrating keratoplasty for keratoconus has a good longterm prognosis; half of the eyes examined in this study had BSCVA ≥ 0.5 at > 20 years after surgery.     

穿透性角膜移植术后继发性青光眼的临床研究

目的:探讨穿透性角膜移植术(penetrating keratoplasty,PK)后继发性青光眼(post-penetrating keratoplasty glaucoma,PPKG)的病因、分类及防治措施。方法:对197例206眼穿透性角膜移植进行回顾性分析。结果:其中52例52眼(25.2%)诊断为PPKG;34例34眼经联合药物治疗后眼压得到控制;18例18眼行手术或激光治疗后眼压控制良好。结论:PK围手术期的正确处理能够降低继发性青光眼的发生率。根据PPKG的不同病因进行不同治疗,疗效满意。     

前节OCT对角膜内皮移植术后植床和植片位置关系的评价

目的应用前节OCT（AS—OCT）对角膜内皮移植术（EK）术后植床和植片的位置关系进行观察。方法回顾性分析2007年9月-2009年4月北京大学眼科中心行角膜后弹力层剥除自动角膜刀取材内皮移植术（DSAEK）的患者42例（44眼）,其中男30例,女12例;年龄15～83岁。术前术后分别行裂隙灯显微镜和AS-OCT检查,对比观察DSAEK术后植片与植床间的位置关系。结果28例患者在裂隙灯显微镜和AS—OCT检查均可清晰地显示植片贴附于角膜后表面、植片位置居中;术后不同时间植片、植床的厚度处于动态变化,随着时间的推移,植床水肿逐渐消退,植片和植床越来越稳定,贴附得更紧密,厚度变得更薄,角膜透明度增加;早期植片完全脱位者5例,占11．36％;植片部分脱位者2例,占4．55％;植片巾央贴附良好,周围卷边者1例,占2．27％;植片偏位者8例,占18．18％。结论AS-OCT是评价EK术后植床和植片位置关系的有效工具。     

兔角膜重度碱烧伤后异种猫前板层角膜移植重建角膜眼表

目的研究猫新鲜前板层角膜移植治疗兔右眼角膜重度碱烧伤的疗效。方法将16只5个月龄的健康雄性新西兰白兔右眼制作重度角膜碱烧伤模型,随机分成A、B两组,每组各8只兔,其中A组为猫(4只)→兔异种前板层角膜移植组,植片直径为11.0mm,植床直径为10.0mm;B组未行手术。A组兔术后及B组造模后用500g.L-1葡萄糖及复方氯霉素滴术眼直至处死,记录两组疗效指数,并分别于术后1个月、2个月、3个月取材进行术眼角膜病理学及扫描电镜检查。结果3个月内A组8只角膜碱烧伤兔经异种猫前板层角膜移植后,7只移植角膜保持透明,1只出现局限性角膜混浊和角膜新生血管;而B组未手术的8只兔中出现角膜白斑、新生血管4只,角膜溃疡、穿孔3只,角膜溶解穿孔1只,并且有4只发生睑球粘连等并发症。A、B两组治疗后1个月、2个月、3个月平均疗效指数差异均有统计学意义(均为P<0.05)。A组透明角膜中组织学及扫描电镜下的结构特征清晰;B组兔角膜中有明显的角膜水肿和炎性细胞浸润,组织学及扫描电镜下的结构特征显示细胞连接混乱、消失。B组扫描电镜还提示随着时间的延长,上皮细胞部分生长、增多,细胞连接差,角膜上皮排列紊乱;角膜内皮细胞数量明显减少或无,...     

异种角膜基质的研究现状及问题

在角膜3层(上皮层+Bowman's膜、基质层、内皮层+Descemet's膜)膜中,按等量计算,基质层的免疫原性是最低的.应用脱细胞的异种角膜基质移植后,神经和基质细胞可以再生,术后未见排斥反应,植片获得透明.因此,异种角膜基质有望成为板层角膜移植的供体和组织工程角膜的载体.现就异种角膜基质的研究现状及问题综述如下.     

深板层角膜移植术治疗角膜疾病的临床分析

目的评价深板层角膜移植术治疗某些角膜疾病的临床疗效。方法回顾性分析我院16例（16眼）罹患角膜疾病但内皮细胞功能正常而行深板层角膜移植者,对所有病例随访6月-2年,观察术后视力、角膜移植片的透明性、角膜上皮完整性及术中术后并发症的情况。结果术后有7眼最佳矫正视力达0．4或0．4以上,5眼达0．1～0．3,4眼达0．05～0．1。角膜移植片透明者9眼,半透明者7眼。主要并发症为术中后弹力层微穿孔6眼,其中3眼术后形成植片轻度水肿,角膜层间少量积液;持续性上皮缺损2眼;真菌性角膜溃疡复发1眼,移植排斥反应1眼,经积极治疗,并发症得到控制,取得良好疗效。结论深板层角膜移植术治疗内皮功能正常的角膜疾病疗效确切,严格掌握手术适应证、提高手术技巧是提高手术成功率的关键。     

316例施行角膜移植术原因的调查分析

目的分析施行角膜移植术的原因。方法对2006至2008年我院进行的角膜移植术316例（316眼）进行回顾性分析。将施行角膜移植术的原因加以分类。结果施行角膜移植术的主要原因依次是感染性（化脓性）角膜炎126例、角膜白斑75例、圆锥角膜36例、单纯疱疹病毒性角膜炎（HSK）21例、化学烧伤16例、遗传相关的角膜营养不良和角膜变性15例、角膜植片排斥13例、大泡性角膜病变6例、角膜皮样瘤4例、角膜穿孔伤4例（4眼）。结论感染性角膜病仍然是角膜移植术的主要适应证,其中真菌感染为首位病因。角膜白斑和圆锥角膜呈上升趋势。