纳米珍珠粉对大鼠钙吸收利用的影响

目的研究纳米珍珠粉对大鼠钙吸收利用的影响,并比较纳米和微米珍珠粉对大鼠生长发育和骨钙水平作用的差异。方法出生21d断乳SD大鼠100只,喂养低钙饲料2周。随机分为5组,雌雄各半,Ⅰ～Ⅱ组分别为微米珍珠粉低、高剂量组,喂饲饲料为低钙饲料混合不同剂量的微米珍珠粉;Ⅲ～Ⅳ分别为纳米珍珠粉低、高剂量组,喂饲饲料为低钙饲料混合不同剂量的纳米珍珠粉;Ⅴ组为低钙对照组,喂饲低钙饲料;另取10只SD大鼠为实验本底组(即Ⅵ组),Ⅵ组于实验开始前处死。实验期为4周。结果2个不同剂量的纳米珍珠粉组的大鼠体重、股骨干重及长度、钙吸收率、钙存留率均高于2个相应剂量的微米珍珠粉组,且差异有显著性(P<0.05)。结论纳米珍珠粉能够被大鼠很好地吸收利用,具有增加骨钙含量的功能,在钙吸收利用作用方面明显优于微米珍珠粉。     

应用便携式数字化温控烫伤仪建立标准化大鼠皮肤烫伤模型

目的:研制一种新型便携式数字化温控烫伤仪,通过自制数字化烫伤仪对大鼠进行烫伤实验,建立标准化大鼠皮肤烫伤模型,从而验证数字化烫伤仪的有效及实用性。方法:选取18只SD大鼠分为对照组(3只,不烫伤);实验组(15只),再将实验组大鼠随机分配为A组(6只)、B组(6只)、C组(3只),选取大鼠背部作为烫伤实验部位:1、时间设定为20 s和30 s,烫伤仪温度分别设定为70℃、80℃、90℃、100℃、120℃,对A组和B组大鼠进行烫伤处理。2、温度设定为100℃,烫伤仪加热时间分别设定为10 s、15 s、25 s,对C组大鼠进行烫伤处理。烫伤后48 h切取实验组和对照组大鼠背部皮肤,进行大体及显微镜下组织病理学观察。结果:70℃20s烫伤点为I°烫伤;70℃30 s、80℃20 s、100℃10 s烫伤点为浅Ⅱ°烫伤;80℃30 s和100℃15 s烫伤点为深Ⅱ°烫伤;90℃20 s、90℃30 s、100℃20 s烫伤点为Ⅲ°烫伤;100℃25 s、100℃30 s、120℃20 s、120℃30 s烫伤点为IV°烫伤。结论:新型便携式数字化温控烫伤仪,可以可靠的建立标准化大鼠皮肤烫伤模型。     

重组融合多肽hEGF-AWRK6的纯化及对小鼠烫伤感染创面愈合的影响

旨在研究重组融合多肽hEGF-AWRK6(EK)对烫伤模型小鼠感染创面的治疗功效。采用大肠杆菌表达系统表达、纯化融合多肽EK,抑菌实验检测EK抑菌活性;构建小鼠II度烫伤和铜绿假单胞菌感染模型,实验组创面滴注EK(30 mg/L),以PBS、庆大霉素(30 mg/L)、烫伤膏(10 mg/L)为对照,计算烫伤后创面愈合率及菌落数;伤后10 d,取各组小鼠的伤口及周边皮肤进行HE染色及胶原蛋白的Western blotting检测,分析创面病理组织结构。实验结果纯化得到了具有抑菌活性的重组表达融合肽EK;伤后6 d始,EK组小鼠创面菌落数少于对照组,差异极显著(P0.01);EK组小鼠烫伤愈合率显著高于PBS对照组(P0.01);与对照组相比,EK组小鼠创面真皮层细胞排列规则,再上皮化较快,毛囊生长较多,Ⅰ型胶原蛋白表达显著增加。结果表明EK具有抑制小鼠烫伤创面感染、促创面愈合功效,具有开发成为治疗烧伤药物的潜力。     

獾油促进深Ⅱ度烫伤小鼠创面愈合作用的研究

目的:检测獾油对小鼠深Ⅱ度烫伤创面愈合的促进作用.方法:制备小鼠深Ⅱ度烫伤模型,分为烫伤对照组(A组)、植物油治疗组(B组)和獾油治疗组(C组).创面依次用生理盐水纱布、植物油纱布、獾油纱布覆盖.无菌纱布包扎固定,每日换药一次.于伤后7天、10天、15天按照Nagelschmidt法观察并记录创面愈合面积,计算创面愈合率;取创面组织,制成石蜡切片,观察病理及组织形态学变化.结果:獾油能加速烫伤创面的再上皮化,促进创面的愈合;提高烫伤组织细胞的增殖活性;促进烫伤创面表皮干细胞的增殖分化.结论:獾油对深Ⅱ度烫伤创面愈合有促进作用     

负压封闭引流对兔颅骨外露创面愈合效果的实验研究

目的:探讨负压封闭引流技术(VSD)对兔颅骨外露缺损创面愈合的治疗效果。方法:选取成年新西兰大白兔76只,平均分为四组并建立兔颅骨外露实验模型。其中,A组(19只):于兔颅骨上方制作直径为2.0cm的圆形创面,保留骨膜,采用-120mmHg负压引流和常规换药治疗;B组(19只):实验动物处理同A组,仅采用常规换药治疗;C组(19只):在兔颅骨上制作直径2.0cm的圆形创面,剔除骨膜,治疗方法同A组;D组(19只):实验动物处理同C组,治疗方法同B组。每组各抽取10只,观察创面愈合率和创面愈合时间;其余9只分别在第7天、10天、20天、30天进行取材检测,分析疗效机制。结果:A组创面愈合时间为19.40±1.65天,B组为24.00±2.31天;C组为25.40±4.43天,D组为30.00±5.50天。运用VSD治疗和常规治疗创面愈合时间比较有统计学意义(P0.05)。结论:VSD治疗兔骨外露缺损创面能有效缩短创面愈合时间,促进血管再生,胶原蛋白合成。     

预见性护理干预预防艾灸烫伤的有效性评价

目的分析预见性护理干预预防艾灸烫伤的有效性。方法收集2018年10月～2019年1月我院收治的接受艾灸治疗的118例患者,随机分为A组(63例)和B组(55例)。A组给予预见性护理,B组给予常规护理。观察艾灸烫伤发生率,并比较治疗前指标评估、健康教育、注意事项告知、治疗期间定时巡视、体位指导和烫伤护理满意度评分。结果 A组无艾灸烫伤发生病例,B组烫伤发生率为9.09%(5/55),两组比较差异有统计学意义(P0.05)。A组的治疗前指标评估、健康教育、注意事项告知、治疗期间定时巡视、体位指导和烫伤护理满意度评分均高于B组(均P0.05)。结论为艾灸治疗患者实施预见性护理能有效预防烫伤,确保治疗安全,且能提高患者的护理满意度,具有一定临床应用价值。     

护理干预预防温针灸烫伤的研究

目的对实施温针灸治疗的患者予以护理干预,且对其预防烫伤的效果进行观察。方法选取我院2014年2月到2015年2月所收治的102例行温针灸治疗的患者作为研究的对象,按随机单盲法分成干预组与常规组,常规组予以常规护理措施,在此基础之上,对干预组患者予以针对性护理干预措施,且对两组患者的烫伤情况加以观察与比较。结果干预组患者的烫伤发生率(2.0%)、护理满意度(98.0%)均优于常规组患者(7.8%、90.2%),差异显著,有统计学意义(P0.05)。结论对温针灸患者予以有效的护理干预措施,可有效预防烫伤的发生,且提升护理满意度,值得大力推广。     

外源性VEGF促进大鼠Ⅱ度烫伤创面中晚期愈合

目的探究Ⅱ度烫伤时外源性血管内皮生长因子(vascular endothelial growth factor,VEGF)对皮肤愈合及其对表皮干细胞(epidermal stem cells,ESCs)迁移、分化的影响方法健康Wistar大鼠随机分为VEGF组、空白对照组、阿西替尼(Axitinib,VEGF抑制剂)组。采用水浴烫伤法制备Ⅱ度烫伤模型,分别以0.2μg/ml VEGF、PBS溶液和10μg/ml阿西替尼处理各组创面,各组均治疗7d,从烫伤至创面愈合分别在第2d、8d、14d及21d测量创面愈合情况,并取创面组织作组织学检测,运用免疫组化技术检测ECSs的分布及数量。结果①创面愈合率:烫伤后21d VEGF组>对照组>阿西替尼组;②愈合速度:烫伤后1-7d空白对照组>阿西替尼组>VEGF组,其后VEGF组愈合速度逐渐加快,第14d开始愈合速度表现为VEGF组>空白对照组>阿西替尼组;③组织学变化:烫伤后8-21d,VEGF组表皮细胞增殖明显,表皮修复和毛囊再生迅速,均早于空白对照组及阿西替尼组。④ECSs阳性细胞率变化:烫伤后第8-14dVEGF组ECSs阳性细胞率明显高于空白对照组和阿西替尼。结论Ⅱ度烫伤时,外源性VEGF在愈合中晚期加快愈合速度使愈合时间明显缩短,并且促进毛囊汗腺的再生使修复后的创面在外观、功能与正常皮肤相近,有助于提高全层皮肤创面的愈合质量。     

深Ⅱ度兔子烫伤模型的建立

目的建立深Ⅱ度家兔烫伤模型。方法采用自行设计的简易高温烫伤装置建立新西兰兔烫伤模型,通过温度和时间两个因素控制烫伤的深度,进行病理切片做组织学检查,判定烫伤的深度。结果当烫伤温度为180℃,烫伤时间10s,可以建立比较标准的深Ⅱ度家兔烫伤模型。结论使用本方法建立模型方法简单,结果稳定,重现性好。     

纳米珍珠粉/壳聚糖-透明质酸支架修复兔股骨远端骨缺损的实验研究

通过体内实验探讨纳米珍珠粉/壳聚糖-透明质酸(NPP/C-HA)复合支架的促成骨能力。采用双侧兔股骨远端骨缺损模型(直径7 mm,深度10 mm),通过大体标本、影像学检查、分子生物学检查及组织学检查来观察骨缺损的修复效果。发现各组均未出现明显不良组织反应;随观察时间增加实验组骨缺损区范围最小,在第8周和第12周数据的差异存在统计学意义(P<0.05);在第4周、6周、8周时实验组BALP含量与其他组比较P<0.05;实验组缺损区边缘出现更多的新生骨,但在骨质成熟度上未见明显差异。结果表明NPP/C-HA支架具有良好的生物相容性及促成骨作用,为进一步研究NPP/C-HA在骨组织工程中的作用提供了实验和理论基础。     

Biophysical properties of corneal cells reflect high myopia progression

Myopia is a common ocular disorder with significant alterations in the anterior ocular structure, including the cornea. The cell biophysical phenotype has been proposed to reflect the state of various diseases. However, the biophysical properties of corneal cells have not been characterized during myopia progression and their relationship with myopia remains unknown. This study characterizes the biophysical properties of corneal cells in normal, myopic, and recovered conditions, using two classical myopia models. Surprisingly, myopic corneal cells considerably reduce F-actin and microtubule content and cellular stiffness and generate elevated traction force compared with control cells. When myopia is restored to the healthy state, these biophysical properties are partially or fully restored to the levels of control cells. Furthermore, the level of chromatin condensation is significantly increased in the nucleus of myopic corneal cells and reduced to a level similar to healthy cells after recovery. These findings demonstrate that the reversible biophysical alterations of corneal cells reflect myopia progression, facilitating the study of the role of corneal cell biophysics in myopia.     

Corneal stem cells and tissue engineering: Current advances and future perspectives

Major advances are currently being made in regenerative medicine for cornea. Stem cell-based therapies represent a novel strategy that may substitute conventional corneal transplantation, albeit there are many challenges ahead given the singularities of each cellular layer of the cornea. This review recapitulates the current data on corneal epithelial stem cells, corneal stromal stem cells and corneal endothelial cell progenitors. Corneal limbal autografts containing epithelial stem cells have been transplanted in humans for more than 20 years with great successful rates, and researchers now focus on ex vivo cultures and other cell lineages to transplant to the ocular surface. A small population of cells in the corneal endothelium was recently reported to have self-renewal capacity, although they do not proliferate in vivo. Two main obstacles have hindered endothelial cell transplantation to date: culture protocols and cell delivery methods to the posterior cornea in vivo. Human corneal stromal stem cells have been identified shortly after the recognition of precursors of endothelial cells. Stromal stem cells may have the potential to provide a direct cell-based therapeutic approach when injected to corneal scars. Furthermore, they exhibit the ability to deposit organized connective tissue in vitro and may be useful in corneal stroma engineering in the future. Recent advances and future perspectives in the field are discussed.     

Matrix metalloproteinases (MMP-2 and MMP-9) activity in corneal ulcer and ocular surface disorders determined by gelatin zymography

The purpose of this paper is to determine the active form of matrix metalloproteinases (MMP-2 and MMP-9) in corneal ulcer and ocular surface disorder patients. A total of 35 patients of corneal ulcer, 20 patients of ocular surface disorders and 10 control subjects were included in this study and estimation of active form of MMP-2 and MMP-9 was done by gelatin zymography. Tear samples were collected by capillary tube method. Both pro- and active forms of MMP-9 were detected in 24 out of 35 patients with corneal ulcer and 15 out of 20 patients with ocular surface disorders. None of the patients were showing MMP-2 activity. Neither MMP-2 nor MMP-9 was detected in the control group. Active forms of MMP-9 are present in tears of severe ulcerative and ocular surface disorder patients. Thus, proteinase inhibitors have been recommended for the treatment of corneal ulcer and ocular surface disorders to reduced the progression of stromal ulcer and to minimize corneal scarring.     

Identification of a cytosolic NADP+-dependent isocitrate dehydrogenase that is preferentially expressed in bovine corneal epithelium. A corneal epithelial crystallin.

Recently, metabolic enzymes have been observed in both the lens and corneal epithelium at levels greatly exceeding what is necessary for normal metabolic functions. These proteins have been termed taxon-specific crystallins and are thought to play a role in maintaining tissue transparency. We report here that cytosolic NADP+-dependent isocitrate dehydrogenase (ICDH) represents a new corneal crystallin. Using suppression subtractive hybridization, we identified a gene (with a deduced amino acid sequence that showed 94% identity to rat cytosolic NADP+-dependent ICDH) that is preferentially expressed in bovine corneal epithelium. Northern blots established that its mRNA level in the corneal epithelium was 31-, 39-, 133-, 230-, and 929-fold more than in the liver, bladder epithelium, stomach epithelium, brain, and heart, respectively. This mRNA was detected primarily in corneal epithelial basal cells by in situ hybridization. SDS-polyacrylamide gel electrophoresis, two-dimensional gel analysis, and Western blotting showed that this protein was overexpressed in the corneal epithelium, constituting approximately 13% of the total soluble bovine corneal epithelial proteins. Enzyme assays showed a corresponding overabundance of this protein in bovine corneal epithelium. Taken together, these data indicate that bovine cytosolic ICDH fulfills the criteria for a corneal epithelial crystallin and may be involved in maintaining corneal epithelial transparency.     

Chondroitin sulfate proteoglycans of bovine cornea: structural characterization and assessment for the adherence of Plasmodium falciparum-infected erythrocytes

The structures of the bovine corneal chondroitin sulfate (CS) chains and the nature of core proteins to which these chains are attached have not been studied in detail. In this study, we show that structurally diverse CS chains are present in bovine cornea and that they are mainly linked to decorin core protein. DEAE-Sephacel chromatography fractionated the corneal chondroitin sulfate proteoglycans (CSPGs) into three distinct fractions, CSPG-I, CSPG-II, and CSPG-III. These CSPGs markedly differ in their CS and dermatan sulfate (DS) contents, and in particular the CS structure-the overall sulfate content and 4- to 6-sulfate ratio. In general, the CS chains of the corneal CSPGs have low to moderate levels (15-64%) of sulfated disaccharides and 0-30% DS content. Structural analysis indicated that the DS disaccharide units in the CS chains are segregated as large blocks. We have also assessed the suitability of the corneal CSPGs as an alternative to placental CSPG or the widely used bovine tracheal chondroitin sulfate A (CSA) for studying the structural interactions involved in the adherence of Plasmodium falciparum-infected red blood cells (IRBCs) to chondroitin 4-sulfate. The data demonstrate that the corneal CSPGs efficiently bind IRBCs, and that the binding strength is either comparable or significantly higher than the placental CSPG. In contrast, the IRBC binding strength of bovine tracheal CSA is markedly lower than the human placental and bovine corneal CSPGs. Thus, our data demonstrate that the bovine corneal CSPG but not tracheal CSA is suitable for studying structural interactions involved in IRBC-C4S binding.     

Corneal Viscoelastic Properties from Finite-Element Analysis of In Vivo Air-Puff Deformation

Biomechanical properties are an excellent health marker of biological tissues, however they are challenging to be measured in-vivo. Non-invasive approaches to assess tissue biomechanics have been suggested, but there is a clear need for more accurate techniques for diagnosis, surgical guidance and treatment evaluation. Recently air-puff systems have been developed to study the dynamic tissue response, nevertheless the experimental geometrical observations lack from an analysis that addresses specifically the inherent dynamic properties. In this study a viscoelastic finite element model was built that predicts the experimental corneal deformation response to an air-puff for different conditions. A sensitivity analysis reveals significant contributions to corneal deformation of intraocular pressure and corneal thickness, besides corneal biomechanical properties. The results show the capability of dynamic imaging to reveal inherent biomechanical properties in vivo. Estimates of corneal biomechanical parameters will contribute to the basic understanding of corneal structure, shape and integrity and increase the predictability of corneal surgery.     

Corneal cell proteins and ocular surface pathology

The cornea is a transparent and avascular tissue that functions as the major refractive structure for the eye. A wide variety of growth factors, chemokines, cytokines and their receptors are synthesized by corneal epithelial and stromal cells, and are found in tears. These molecules function in corneal wound healing and in inflammatory responses. Proteoglycans and glycoproteins are essential for normal corneal function, both at the air-epithelial interface and within the extracellular matrix. The ocular MUC mucins may play roles in forming the mucus layer of the tear film, in regulating tear film spread, and in inhibiting the adhesion of pathogens to the ocular surface. Lumican, keratocan and mimecan are the major keratan sulfate proteoglycans of the corneal stroma. They are essential, along with other proteoglycans and interfibrillar proteins, including collagens type VI and XII, for the maintenance of corneal transparency. Corneal epithelial cells interact with a specialized extracellular matrix structure, the basement membrane, composed of a specific subset of collagen type IV and laminin isoforms in addition to ubiquitous extracellular matrix molecules. Matrix metalloprotein-ases have been identified in normal corneal tissue and cells and may play a role in the development of ulcerative corneal diseases. Changes in extracellular matrix molecule localization and synthesis have been noted in other types of corneal diseases as well, including bullous keratopathy and keratoconus.     

Rabbits' corneal cells studied in tissue cultures

Summary Enzymatic reactions of corneal epithelial cells are, by and large, stronger than reactions of corneal fibroblasts.The cytoplasm of corneal epithelial cells and fibroblasts has stronger enzymatic activity than the nuclei of the two types of cells.The nuclei of epithelial cells react stronger than the nuclei of fibroblasts.Certain enzymes have a fairly characteristic cytoplasmic distribution in corneal epithelial cells but not in fibroblasts. The intensity of some enzyme reactions changes with aging of the cells.This study was aided in part by an institutional grant from the Lilly Research Laboratories, Indianapolis, Ind.     

Keratan sulfate: structure, biosynthesis, and function

The last 5 years have seen a marked increase in research on keratan sulfate (KS) and a concomitant increase in our understanding of the range of molecules that carry this adaptable polysaccharide. More than 15 KS-linked proteins have been identified and many of the genes encoding these have been cloned. KS-containing molecules have been identified in numerous epithelial and neural tissues in which KS expression responds to embryonic development, physiological variations, and to wound healing. A corneal cell culture system has been developed in which long-term KS biosynthesis is maintained. Progress has been made toward identification of the glycosyl- and sulfotransferases responsible for KS biosynthesis. A mouse knockout of a corneal KS-proteoglycan has provided the first experimental support for the role of KS in corneal transparency. Evidence has also been presented supporting functional roles of KS in cellular recognition of protein ligands, axonal guidance, cell motility, and in embryo implantation. These findings have served to expand the concept of what keratan sulfate is and the potential roles it may play in the cellular biology of diverse tissues.     

Genetics of corneal endothelial dystrophies

The corneal endothelium maintains the level of hydration in the cornea. Dysfunction of the endothelium results in excess accumulation of water in the corneal stroma, leading to swelling of the stroma and loss of transparency. There are four different corneal endothelial dystrophies that are hereditary, progressive, non-inflammatory disorders involving dysfunction of the corneal endothelium. Each of the endothelial dystrophies is genetically heterogeneous with different modes of transmission and/or different genes involved in each subtype. Genes responsible for disease have been identified for only a subset of corneal endothelial dystrophies. Knowledge of genes involved and their function in the corneal endothelium can aid understanding the pathogenesis of the disorder as well as reveal pathways that are important for normal functioning of the endothelium.