生物羊膜冷冻干燥工艺优化研究

为探索羊膜冷冻干燥保存的最佳工艺条件,取健康剖宫产产妇胎盘,钝性剥离羊膜。以保存羊膜组织形态变化、胶原蛋白酶降解速度、生物力学特征、细胞因子含量为考察指标,对羊膜冷冻干燥工艺中的关键因素进行优化。结果显示,改良冷冻干燥羊膜上皮细胞、纤维基质层形态结构与新鲜羊膜基本相同,但纤维基质厚度略有增加,上皮细胞表面微绒毛略有减少;Ⅳ型胶原酶在溶液中降解速度有所加快;生物力学特征与新鲜羊膜无明显差别;6种细胞因子含量明显低于新鲜羊膜。结合前期工作,与常规冷冻干燥法比较,改良冷冻干燥工艺对保存羊膜组织结构和生物学活性因子影响较小,并能使保存羊膜具有更好的生物力学特性。     

角膜基质内羊膜移植修复大泡性角膜病变

BACKGROUND: Bullous keratopathy has an increasing annual incidence, but its treatment is restricted by few sources of materials for corneal transplantation and high cost of operation. Additionally, some patients who present with serious symptoms have little chance of recovery and low success in corneal transplantation. Amniotic membrane from the corneal stroma has a rich source with low cost, which can effectively relieve the symptoms and improve the quality of life in patients. OBJECTIVE: To observe the therapeutic efficacy of amniotic membrane implantation into the corneal stroma in the treatment of bullous keratopathy. METHODS: Forty healthy adult New Zealand rabbits (half male and female) were randomly divided into four groups (A, B, C, D groups), with 10 rats in each group. Rabbit models of bullous keratopathy were made in the groups A, B, C. At 2 weeks after modeling, amniotic membrane implantation into the corneal stroma and corneal surface was performed in groups A and B, respectively, and in group C, corneal lamellar dissection was done but with no amniotic membrane transplantation. In group D, there was no surgical treatment (blank control). A slit lamp microscope with constant crack width and angle of light projection was used to observe the central corneal thickness, and corneal opacification degree, corneal epithelial bulla of rabbits were observed at different time in each group. Under microscope, the rabbit corneal endothelial cells and healing were observed at different time. RESULTS AND CONCLUSION: At 1 day and 2 weeks after transplantation, the central corneal thickness of rabbits had significant differences in the four groups (P < 0.05). At 4, 8, 12 weeks after transplantation, the central corneal thickness of rabbits showed no difference between groups A and B as well as between groups C and D (both P > 0.05), but there was a significant difference between groups A, B and group C  (P < 0.05). At 4 and 8 weeks after transplantation, the degree of corneal opacity was significantly better in group A than the other three groups (P < 0.05). There were obvious scars forming at the incision of rabbits in the group C. Compared with the other three groups, the bulla was improved better in the group A (P < 0.05). At 2 weeks after transplantation, bullous keratopathy relapsed in the group B, and symptoms of edema with bulla were still seen in groups C and D at 12 weeks after transplantation. These findings indicate that amniotic membrane implantation into the corneal stroma can effectively repair rabbit corneal endothelial cells and alleviate the symptoms of edema, but its specific mechanism need to be further studies.     

羊膜上皮细胞和羊膜间充质干细胞构建组织工程皮肤

背景：由于人胎盘来源的间充质干细胞具有多方面的优点,近年来已成为干细胞研究的热点。 目的：分析鉴定羊膜间充质干细胞和羊膜上皮细胞的生物学特性,探讨其作为皮肤种子细胞在三维气液培养构建组织工程皮肤中的应用情况。 方法：用胰酶胶原酶多步消化法获取羊膜间充质干细胞和羊膜上皮细胞,通过流式细胞术、反转录-聚合酶链反应和免疫荧光染色技术,鉴定两种细胞的表面分子标记、干细胞特性、与皮肤角质形成细胞的相似性,并利用两种细胞为种子细胞以鼠Ⅰ型胶原为基质进行三维气液培养。 结果与结论：①流式细胞术检测体外培养羊膜间充质干细胞和羊膜上皮细胞均高表达CD90、CD73、CD105,不表达造血干细胞标志CD34以及MHC-Ⅱ类分子HLA-DR。②反转录-聚合酶链反应检测到羊膜间充质干细胞表达干细胞特性基因CMCY和NANOG,羊膜上皮细胞表达干细胞特性基因CMCY和 KLF4,两种细胞均有干细胞特性。③反转录-聚合酶链反应检测羊膜间充质干细胞表达皮肤角质形成细胞特性基因K19、β1-integrin、K8,羊膜上皮细胞表达K19、β1-integrin、K5、K8,免疫荧光染色见羊膜上皮细胞表达与角质形成细胞增殖相关的的特性蛋白K14,说明羊膜上皮细胞与皮肤角质形成细胞更具相似性, 在特定条件下更易于分化为皮肤角质形成细胞。④利用两种细胞成功构建组织工程皮肤,苏木精-伊红染色切片显示其具有一定的皮肤结构,且羊膜上皮细胞发生了初步分化。以上结果说明羊膜间充质干细胞与羊膜上皮细胞通过三维培养构建人皮肤组织是可行的。     

人羊膜上皮细胞体外培养重建角膜上皮的实验研究

目的: 探讨人羊膜上皮细胞(human amniotic epithelial cells, HAECs)诱导分化为角膜上皮细胞的可塑性及其重建角膜上皮的可行性。方法: 取足月产人羊膜,通过胶原酶、胰蛋白酶和EDTA消化获得HAECs,将细胞在体外培养扩增、传代,将2~3代HAECs接种于去上皮的兔角膜基质上培养,待HAECs融合形成单层后,置于插入式培养皿中进行气液界面培养14 d。对角膜基质上培养的HAECs用光镜、扫描电镜和透射电镜进行形态学及超微结构观察,以及细胞角蛋白(CK)3/12的免疫组织化学检测。结果: HAECs可在角膜基质上生长,培养1~2 d可形成单层,气液界面培养14 d可形成4~5层细胞的复层上皮,扫描电镜观察细胞表面有丰富的微绒毛,透射电镜下可见上皮细胞之间有桥粒连接,免疫组化检测复层细胞表达CK3/12,所形成的复层结构与正常角膜上皮相似。结论: HAECs有可能作为种子细胞用于组织工程角膜上皮重建。     

羊膜修复肌腱、韧带损伤的研究进展

肌腱、韧带损伤后造成缺损、粘连和功能障碍的问题,当今尚未得到解决。组织工程技术,特别是生物羊膜,在眼科、烧伤整形科、耳鼻喉科等专科已经得到了较好的应用,羊膜能否用于肌腱、韧带的损伤修复目前尚无足够多的研究。本研究拟就羊膜特性及其在修复肌腱、韧带损伤方面的应用加以概述。     

HLA匹配角膜缘干细胞联合羊膜移植修复翼状胬肉

背景：HLA匹配的角膜缘干细胞联合羊膜移植治疗翼状胬肉是眼科医生治疗的新理念,该方法治疗后并发症少、康复快、复发率低,尤其是能减少移植排斥反应等已被广泛接受。 目的：探讨HLA匹配的角膜缘干细胞联合羊膜移植治疗翼状胬肉疗效。 方法：选取2013年3月1日至2014年4月30日行HLA匹配的角膜缘干细胞联合羊膜移植治疗的翼状胬肉患者47例(47眼)作为试验组;回顾性分析2010年3月1日至2012年12月1日采用单纯翼状胬肉切除方法治疗的翼状胬肉患者40例(47眼)作为对照组,对两组患者治愈和复发情况进行比较。 结果与结论：试验组47例,全部顺利完成治疗,无并发症,其中1例切口感染,特殊对症治疗后均已好转出院,全部患者均无移植排斥反应。试验组治愈45眼,复发2眼,复发率为4.3%。对照组47眼中治愈32眼,复发15眼,复发率31.9%。结果表明HLA匹配的角膜缘干细胞联合羊膜移植治疗翼状胬肉并发症少、复发率低,是治疗翼状胬肉一种行之有效的方法。中国组织工程研究杂志出版内容重点：干细胞;骨髓干细胞;造血干细胞;脂肪干细胞;肿瘤干细胞;胚胎干细胞;脐带脐血干细胞;干细胞诱导;干细胞分化;组织工程全文链接：     

体外培养人羊膜上皮细胞的表型及分化能力

背景：人羊膜上皮细胞具有多系分化能力,是再生医学中重要的细胞来源。目前的研究多集中于对其分化能力的考察,而体外培养过程中羊膜上皮细胞的生物学特征如何变化尚不清楚。 目的：分析体外培养对人羊膜上皮细胞生长、表型及向心肌样细胞分化的能力等生物学特性的影响,探讨原代人羊膜上皮细胞干性标志物SSEA-4的表达水平与人羊膜上皮细胞生物学特性变化之间的关联性。 方法：使用统一分离方法获得原代羊膜上皮细胞并进行体外培养。利用CCK-8、流式细胞仪及real-time PCR等手段检测不同培养阶段人羊膜上皮细胞的增殖、表型以及向心肌样细胞分化的能力。 结果与结论：不同胎儿样本来源的原代人羊膜上皮细胞的SSEA-4表达在26.7%-97%,存在很大的个体差异。并且,随着传代次数的增加,人羊膜上皮细胞的SSEA-4表达水平显著降低,其下降程度与原代SSEA-4的表达水平无关。另外,培养后人羊膜上皮细胞的心肌分化潜能也存在很大个体差异,且其差异与原代人羊膜上皮细胞的SSEA-4表达水平的高低无关。结果提示,不同胎儿样本来源的原代人羊膜上皮细胞的SSEA-4表达水平受到个体差异的影响,需要建立更准确的临床样本筛选指标来稳定获得原代高表达SSEA-4的胎儿样本,以实现对人羊膜上皮细胞的质量监控。另外,体外培养过程中SSEA-4的表达水平受到培养条件的影响,需要继续优化培养条件以维持其高表达。此外,人羊膜上皮细胞向心肌样细胞分化的能力受到样本个体差异以及培养条件的影响,在今后还需要进一步研究。 中国组织工程研究杂志出版内容重点：组织构建;骨细胞;软骨细胞;细胞培养;成纤维细胞;血管内皮细胞;骨质疏松;组织工程全文链接：     

色素上皮衍生因子对角膜碱烧伤后新生血管形成的抑制

背景：角膜新生血管导致角膜透明性降低,造成严重的视觉障碍。色素上皮衍生因子是一种内源性血管生成抑制剂,其对于角膜新生血管是否具有抑制作用尚不清楚。 目的：探索局部运用色素上皮衍生因子对大鼠角膜碱烧伤后角膜新生血管的抑制作用。 方法：将20只大鼠随机分为生理盐水组与色素上皮衍生因子组,每组10只。用NaOH溶液将大鼠右眼角膜烧伤诱导产生新生血管。碱烧伤后2组每日分别给予生理盐水和色素上皮衍生因子点眼,并采用裂隙灯显微镜观察和测量各组角膜新生血管生长情况。碱烧伤后12 d处死大鼠,将角膜组织固定切片,行苏木精-伊红染色观察,并进行免疫组织化学染色检测各组大鼠角膜血管内皮生长因子和CD31的表达。 结果与结论：大鼠角膜碱烧伤后3,7,12 d,色素上皮衍生因子组大鼠角膜新生血管面积均小于生理盐水组(P < 0.05)。角膜碱烧伤后12 d,苏木精-伊红染色显示生理盐水组大鼠角膜产生大量新生血管,角膜组织结构紊乱;色素上皮衍生因子组新生血管较少,角膜组织结构趋于整齐。角膜碱烧伤后12 d,免疫组织化学染色示生理盐水组大鼠角膜上皮和基质层可见血管内皮生长因子大量表达,角膜基质层可见血管内皮生长因子和CD31大量表达;色素上皮衍生因子组新生血管稀少,CD31表达较弱。证实局部应用色素上皮衍生因子可有效抑制大鼠角膜化学伤后的血管新生。     

兔角膜缘上皮细胞羊膜种植及生物学特性研究

研究兔角膜缘上皮细胞(含干细胞)在完整羊膜和去上皮羊膜上种植及生物学特征,探讨组织工程技术体外重建角膜上皮良好的方式和方法.将兔角膜缘上皮细胞分别种植于去上皮羊膜基底膜和完整羊膜上进行体外培养扩增.从倒置显微镜下的生长特性、光镜下的组织结构、超微结构、免疫组织化学检测等方面对培养获得的复合组织进行观察.结果表明兔角膜缘上皮细胞在完整羊膜上不易贴壁、生长缓慢、很难汇合成片.而在去上皮羊膜上细胞能黏附生长并增殖形成由羊膜基底膜和4～5层上皮细胞组成的复合组织,基底层细胞与羊膜之间有半桥粒连接,细胞之间可见桥粒连接,细胞表达角蛋白3.该复合物可作为组织工程化角膜上皮组织.     

他莫昔芬对急性脊髓损伤模型大鼠的神经保护

BACKGROUND:Tamoxifen has been found to exert neuroprotection by reducing cerebral hemorrhage and edema surrounding the injured site of the spinal cord. OBJECTIVE:To investigate the neuroprotective effect of tamoxifen on rat acute spinal cord injury and the underlying mechanism. METHODS: Sixty Sprague-Dawley rats were equivalently randomized into five groups, and modeled into spinal cord injury at T10 level using modified Allen’s weight-drop method (70 g/cm), except those in sham operation group. At 30 minutes after modeling, all rats were given the intraperitoneal injection of 2.5, 5.0 and 10 mg/kg tamoxifen or same amount of normal saline, once daily. Basso, Beattie, Bresnahan (BBB) scores were recorded at 24, 48 and 72 hours after surgery. The injured spinal cord was removed at 72 hours to observe its edema. Meanwhile, the levels of interleukin-1β, interleukin-10 and tumor necrosis factor-α, as well as Caspase-3 activity were detected by ELISA; the protein levels of nuclear factor-κB p65, phosphorylated I-κBα and Caspase-3 were detected by western blot assay. RESULTS AND CONCLUSION: Compared with the model group, the hind limb function in the tamoxifen groups was significantly improved. Tamoxifen significantly decreased the water content in the rat spinal cord and inhibited spinal cord edema at 72 hours after surgery. ELISA results showed that tamoxifen significantly reduced the activity of interleukin-1β, interleukin-10, tumor necrosis factor-α and Caspase-3 (P < 0.05). Western blot assay revealed that tamoxifen significantly downregulated the expression levels of nuclear factor-κB p65, phosphorylated I-κBα and Caspase-3. These results suggest that tamoxifen protects against spinal cord injury via suppressing inflammatory response and apoptosis-associated proteins. 中国组织工程研究杂志出版内容重点：组织构建;骨细胞;软骨细胞;细胞培养;成纤维细胞;血管内皮细胞;骨质疏松;组织工程     

Avastin对小鼠角膜碱烧伤后新生淋巴管形成的影响

目的观察小鼠角膜碱烧伤后新生淋巴管形成情况,探讨Avastin对小鼠角膜碱烧伤后新生淋巴管形成的影响及其机制。方法制作小鼠角膜碱烧伤模型,随机分为治疗组和烧伤组,烧伤组连续两周内每日左氧氟沙星滴眼液滴眼3次,治疗组连续两周内应用25mg/ml Avastin结膜下隔日注射5μl+每日左氧氟沙星滴眼液滴眼3次,分别于碱烧伤后3d、5d、7d、12d和18d取材。采用免疫组化法,观察VEGF-C在碱烧伤后不同时间段角膜组织内的表达;应用淋巴管内皮透明质酸受体(LYVE-1)标记淋巴管内皮,观察小鼠角膜内新生淋巴管的形成情况。结果在正常小鼠角膜组织内,VEGF-C表达于角膜上皮层和内皮层。在烧伤组碱烧伤角膜内,VEGF-C主要表达于角膜上皮细胞和角膜基质内入侵的炎性细胞,于碱烧伤后3d,VEGF-C的表达达到高峰(0.05),碱烧伤后12d,VEGF-C的表达恢复至正常水平。在治疗组碱烧伤角膜内,VEGF-C的表达在碱烧伤后3d低于烧伤组。Avastin治疗组角膜内,碱烧伤后12d见LYVE-1阳性表达开放状态的新生淋巴管,淋巴管出现的时间较烧伤组明显延迟。结论 Avastin能减少小鼠碱烧伤后角膜新生淋巴管的形成,其机制可能与抑制角膜组织内淋巴管生成因子VEGF-C的表达相关。     

重组IFN-α蛋白联合endostatin基因对碱烧伤诱导角膜新生血管的抑制作用

目的探讨重组IFN-α蛋白联合endostatin基因对碱烧伤诱导角膜新生血管的抑制作用。方法兔眼球结膜下注射包有绿色荧光蛋白表达载体的脂质体，3d后用激光共聚焦显微镜观察角膜绿色荧光蛋白表达。利用碱烧伤法制备兔眼角膜新生血管模型，球结膜下联合注射重组IFN-α蛋白及包有endostatin真核表达载体的脂质体，用裂隙灯显微镜观察对新生血管的抑制作用。结果实验组角膜有很强的绿色荧光，而在对照组则无荧光。联合应用重组IFN-α蛋白和endostatin基因治疗，第7、10、13天角膜新生血管长度、面积明显小于重组IFN-α蛋白和endostatin基因的单独治疗组（P〈0．05）。结论重组IFN-α蛋白联合endostatin基因可有效抑制碱烧伤诱导角膜新生血管的生长。     

Comparative evaluation in the use of topical corticosteroid in the management of corneal alkali burn ulcers in rabbits

This study was performed to evaluate the addition of steroidal or non-steroidal, anti-inflammatory agents or topical medroxyprogesterone acetate to tetracycline and vitamin C in the management of ocular alkali burns. Alkali wounds were created on the central corneas of rabbits by applying a round filter paper, 12?mm in diameter, soaked in 1?M NaOH for 30?s. Only one eye in each rabbit was treated. A total of 25 rabbits were divided into five groups with five animals each. Five rabbits without treatment after the alkali burn were designated as the control group. In the remaining four groups, topical tetracycline and systemic vitamin C treatment were included. In group A, 1% topical medroxyprogesterone acetate, in group B, 1% topical prednisolone acetate and in group C, topical diclofenac were used. In group D, corneal ulcers were treated with only tetracycline and vitamin C. Clinical outcome was monitored daily by corneal opacity, duration of blepharospasm, corneal vascularization, and duration of ocular discharge. After 3?weeks, corneas were excised for histopathological analysis. Samples were monitored by evaluating corneal thickness (μm), numbers of epithelial rows, keratocyte density, stromal vascularization, stromal inflammation, and stromal collagen arrangement. Comparison between groups showed that groups A, B, and C had significantly lower discharge days, and groups B and C had significantly shorter duration of blepharospasm than the control group. In the microscopic evaluation of the corneas, groups B and C had a significantly lower degree of corneal vascularization, and group B had significantly lower degree of corneal inflammation than the control group. In conclusion, the topical application of 1% prednisolone combined with vitamin C and tetracycline may be therapeutically valuable in the early treatment (first 3?weeks) of corneal alkali burns.     

The effect of sub-conjunctival platelet-rich plasma in combination with topical acetylcysteine on corneal alkali burn ulcer in rabbits

An experimental study examined the effect of sub-conjunctival platelet-rich plasma (sPRP) in combination with topical acetylcysteine on corneal alkali burn ulcers in rabbits. A total of 20 rabbits were used in this study. After collecting intracardiac blood samples from ten rabbits, platelet-rich plasma was obtained by centrifugation. Alkali wounds were inflicted on the central corneas of rabbits by applying a round filter paper, 6.0 mm in diameter, soaked in 1 M NaOH for 60 s. Only one eye in each rabbit was used. A total of 20 rabbits were allocated into four groups of five animals each. Group 1 served as the control group. Group 2 received 3% N-acetylcysteine (NAC) topically three times daily for 2 weeks. The third group received only sPRP whereas group 4 received sPRP with topical 3% NAC three times daily for 2 weeks. Clinical outcome was monitored by evaluation of epithelial defects, corneal opacity, duration of blepharospasm, corneal vascularisation, duration of ocular discharge and wound area diameter measurement. After 3 weeks eyes were enucleated and corneas were excised for histopathological analysis. Samples were assessed by evaluating the number of epithelial rows, stromal vascularisation and inflammation and stromal collagen arrangement. Comparison between groups showed that group 3 had significantly shorter duration of blepharospasm than the control group. Additionally, group 3 had smaller mean defect area and greater wound healing. Histopathlogical investigation revealed significantly less inflammation and vascularisation in the corneas in group 3; this group also had the best stromal collagen arrangement. In conclusion sPRP seems to improve corneal epithelial burn healing. However, acetylcysteine and sPRP combination may have a retarded healing effect as compared with platelet-rich plasma alone.     

组织工程角膜内皮层移植的研究与应用

背景：组织工程角膜内皮可以克服角膜内皮移植的短缺并能够改善角膜内皮细胞的质量,其应用前景十分广阔。因此,寻找一种理想的重建角膜内皮方法是组织工程角膜研究领域的重要课题和研究热点。 目的：总结并讨论组织工程角膜内皮重建的研究进展。 方法：应用计算机检索PubMed 数据库(http://www.ncbi.nlm.nih.gov/PubMed)相关文章,检索时间为2000至2012年,检索词为“corneal endothelial cell,transplantation,tissue engineering”,并限定文章语言种类为英语,然后再从中筛选出与主题相关的部分文献。 结果与结论：初检得到163篇文章,按主题相关性对文献进一步筛选,最终纳入44篇文章。目前构建单层角膜内皮层的研究较多,也取得了巨大的成绩,但是仍没有一种材料或重建方式可以完全符合临床应用的组织工程的人角膜内皮。每一种材料和方法都各有优缺点,克服这些缺点以及观察在体内的长期影响是今后的发展方向。     

Effects of sutureless amniotic membrane patching with 2-Octyl cyanoacrylate (Dermabond) on experimental corneal alkali burn in dogs

This study was performed to evaluate the surgical technique required and the clinical usefulness of tissue adhesive (2-Octyl cyanoacrylate) combined with amniotic membrane (AM) patching in the treatment of experimental corneal burn in dogs. Alkali wounds were inflicted on the central corneas of dogs by applying a round filter paper, 6.0 mm in diameter, soaked in 1 M NaOH for 60 s. Only one eye in each dog was used. A total of 15 dogs were divided into three groups of five animals each: (1) uncovered—control, (2) covered by AM with the amnion cell side down and secured with 10–0 nylon sutures to the cornea around the wound area—AM + suture, and (3) covered by sutureless AM patching secured with 2-Octyl cyanoacrylate (Dermabond)—AM + glue. The operating time was compared between both treatment groups. Clinical outcome was monitored by evaluation of epithelial defects, corneal opacity, duration of blepharospasm, time of AM persistence, corneal vascularisation, and duration of ocular discharge. The mean surgery time in AM + suture group was significantly longer than AM + glue group. AM persistence in AM + glue group was significantly greater than AM + suture group. The duration of ocular discharge and corneal vascularisation in AM + glue group was significantly lower in comparison with control group. Epithelial healing was faster in the AM + glue group than in controls. In conclusion, sutureless AM patching with 2-Octyl cyanoacrylate (Dermabond) as a dressing on a corneal alkali burn, used for the first time in this research, may induce rapid epithelial healing with less vascularisation and be a much faster and useful technique in dogs.     

The effect of gamma irradiation on injectable human amnion collagen

The effect of gamma irradiation on the physicochemical properties of injectable human amnion collagen was investigated. Pepsin-extracted human amnion collagen was purified, reconstituted, and irradiated with varying doses of gamma irradiation (0.25 Mrads to 2.5 Mrads). Gamma irradiation had a significant impact on the physical characteristics of the collagen. The neutral solubility of collagen in PBS at 45 degrees C was decreased from 100% for the nonirradiated control sample to 16% for the 2.5 Mrads irradiated sample. SDS polyacrylamide gel electrophoresis also demonstrated the dose-dependent effect of gamma irradiation on collagen cross-links. Electron microscopic observation revealed that even at low irradiation dose (0.25 Mrads), collagen fibril diameter increased. The average diameter was 50 nm for nonirradiated control fibrils, while 4.4 percent of the irradiated collagen fibrils had a diameter greater than 100 nm. Irradiated collagen showed little evidence of damage. Well-preserved cross-striations were found in collagen fibrils at all doses of irradiation. Native amnion collagen irradiated with gamma rays demonstrated a slight increase in resistance to collagenase degradation compared with nonirradiated native collagen samples. Increased resistance to collagenase did not correlate with increasing irradiation dose. After 30 min of incubation at 37 degrees C, both irradiated and nonirradiated collagen was completely digested by collagenase. However, gamma-irradiated collagen did become more sensitive to hydrolysis by trypsin. The higher the irradiation doses used, the greater sensitivity to trypsin was observed. At 0.25 Mrads irradiation only a slight increase was found. No marked differences in amino acid composition were noted among the high dose irradiated, low dose irradiated and control amnion collagen.     

Flow sterilization of peritoneal dialysate by ultraviolet irradiation

Conclusions 1. A low-pressure mercury lamp can be used for the ultraviolet irradiation sterilization of transparent liquid media. 2. The design of a flow ultraviolet irradiation sterilization unit provides for conversion of the bulk flow into a thin layer, thus promoting efficient sterilization by using the full power of the radiation source and achieving good processing rates. 3. The useful power of the sterilization unit provides 163 times the lethal dose of bactericidal radiation for spores of microorganisms in transparent solution. 4. The method of flow ultraviolet irradiation sterilization is economical for treatments requiring the consumption of large volumes of solutions. 5. The optical density of water and aqueous solutions increases proportionally to the dose of irradiation at 254 nm. Department of Hemodialysis and Kidney Transplantation, Moldavian Republic Clinical Hospital, Kishinev. Scientific-Research Institute of Transplantation and Artificial Organs, Moscow. Translated from Meditsinskaya Tekhnika, No. 4, pp. 35–38, July–August, 1991.     

Expression of Smad7 in mouse eyes accelerates healing of corneal tissue after exposure to alkali

Damage to the cornea from chemical burns is a serious clinical problem that often leads to permanent visual impairment. Because transforming growth factor (TGF)-beta has been implicated in the response to corneal injury, we evaluated the effects of altered TGF-beta signaling in a corneal alkali burn model using mice treated topically with an adenovirus (Ad) expressing inhibitory Smad7 and mice with a targeted deletion of the TGF-beta/activin signaling mediator Smad3. Expression of exogenous Smad7 in burned corneal tissue resulted in reduced activation of Smad signaling and nuclear factor-kappaB signaling via RelA/p65. Resurfacing of the burned cornea by conjunctival epithelium and its differentiation to cornea-like epithelium were both accelerated in Smad7-Ad-treated corneas with suppressed stromal ulceration, opacification, and neovascularization 20 days after injury. Introduction of the Smad7 gene suppressed invasion of monocytes/macrophages and expression of monocyte/macrophage chemotactic protein-1, TGF-beta1, TGF-beta2, vascular endothelial growth factor, matrix metalloproteinase-9, and tissue inhibitors of metalloproteinase-2 and abolished the generation of myofibroblasts. Although acceleration of healing of the burned cornea was also observed in mice lacking Smad3, the effects on epithelial and stromal healing were less pronounced than those in corneas treated with Smad7. Together these data suggest that overexpression of Smad7 may have effects beyond those of simply blocking Smad3/TGF-beta signaling and may represent an effective new strategy for treatment of ocular burns.