髁突骨上组织扫描电镜和透射电镜的比较研究

目的 比产髁突骨上组织在扫描电镜（ＳＥＭ）和透射电镜（ＴＥＭ）下的不同表现特点，方法 ３只成年健康家兔在侧髁突断裂后用ＳＥＭ的方法观察断面的结构，右侧做常规ＴＥＭ检查，结果 ＳＥＭ发现，髁突软骨细胞似表面呈蜂窝样的球体，胞内有多个空泡存在，钙化的软骨细胞这种表面形态消失，不规则地皱缩，ＴＥＭ下，软骨细胞似透明软骨细胞的典型形态，有短小突起，周围有半透明的薄带，钙化的软骨细胞内细胞器用明显减少，部分     

脉冲电磁场和功能矫形对大鼠下颌髁突IGF-I表达影响的研究

将２０只青春期雄性ＳＤ大鼠随机等量分为对照组,脉冲电磁场（ＰＥＭＦ）组,戴功能矫治器（ＦＡ）组及二者共同作用（ＰＥＭＦ＋ＦＡ）组,研究脉冲电磁场和功能矫治器对大鼠下颌髁突胰岛素样生长因子Ｉ（ＩＧＦ—Ｉ）表达变化。经过１０天的实验,结果发现ＰＥＭＦ和功能矫治器都可显著性增加髁突软骨细胞的ＩＧＦ—Ｉ表达,提示二者具有协同作用,为临床联合使用ＰＥＭＦ和ＦＡ进行下颌骨的矫形治疗提供了实验依据。     

SV40诱导髁突软骨细胞永生化的实验研究

目的 建立髁突软骨细胞的永生化细胞系。方法 构建含有ＳＶ４０大Ｔ抗原基因和ｎｅｏ抗性基因的逆转录病毒载体ｐＬＮ／ＳＶ４０，用常规脂质体转染的方法将目的基因导入包装细胞ＰＡ３１７，Ｇ４１８筛选出阳性克隆后，收集其病毒上清感染原代培养的新西兰白兔髁突软骨细胞（ｍａｎｄｉｂｕｌａｒ ｃｏｎｄｙｌａｒ ｃｈｏｎｄｒｏｃｙｔｅ，ＭＣＣ），Ｇ４１８筛选阳性克隆并挑选单克隆。设计大Ｔ抗原基因的特异性引物，用ＰＣＲ检测不同克隆株对目的基因的整合。对所挑选的阳性克隆株进行扩增培养及常规的冻存复苏，比较其与ＭＣＣ在形态增殖等方面的特征。结果 １０个阳性克隆株成功扩增出了１１９６ｂｐ的基因片断，有５株细胞传代超过３０次，其中克隆株Ａ２１已在体外１．５年稳定传代１００次以上，命名为永生化髁突软骨细胞（ｉｍｍｏｒｔａｌｉｚｅｄ ｍａｎｄ     

体内压应力刺激下大鼠髁突软骨细胞的分离、体外培养以及差异蛋白质组学观察

目的：观察体内压应力刺激下大鼠髁突软骨细胞的生物学活性和蛋白质表达谱。方法：对大鼠进行III类矫形力应力加载2周,观察髁状突大体形态和组织形态学;体外培养实验鼠和对照鼠软骨细胞,计数细胞收获数和细胞存活率,检测总蛋白质组学水平上差异。结果：压力刺激后的大鼠髁突软骨明显变薄,表面无光泽,缺乏弹性,重量降低（P＜0．01）;力学刺激后髁突软骨细胞收获率和存活率均下降（P＜0．01）,形态更加狭长;蛋白质组学结果主要为应激蛋白上调,信号转导蛋白活化,细胞骨架蛋白和细胞增殖代谢相关蛋白的下降。结论：经体内力学加载后,体外分离培养的关节软骨细胞形态、生物学活性以及在蛋白质水平均发生了明显的变化。     

髁突纵行骨折与横断骨折的对比实验研究

目的 探讨幼年期髁突纵行和横断骨折对颞下颌关节的继发性影响。方法 中国实验用小型猪１４头,２－３月龄,分别造成左侧髁突纵行和横断骨折模型。在术后３个月与６个月进行肉眼和光镜观察。结果 髁突横断骨折引起ＴＭＪ的适应性变化,而髁突纵行骨折后ＴＭＪ形成明显的关节盘髁突粘连及双髁突畸形。光镜下显示：盘突 组织内可见大量成纤维细胞及软骨细胞,关节盘内出现血管及脂肪细胞。结果 幼年期髁突纵行与横断骨折对ＴＭＪ     

功能矫形前伸大鼠下颌后髁突软骨β转化生长因子Ⅰ型受体(TβR-Ⅰ)表达变化的研究

目的：了解青春期ＳＤ大鼠髁突软骨β转化生长因子Ⅰ型受体（ＴβＲ－Ⅰ）在功能矫形前伸下颌后分布的变化，探讨ＴβＲ－Ⅰ与ＴＧＦ－β１表达的关系。方法：实验组戴模拟临床功能矫治器，引导大鼠下颌前伸，并在实验３ｄ，１，２，３和４周各处死５只大鼠，取下髁突，应用免疫组织化学方法探测β转化生长因子Ⅰ型受体（ＴβＲ－Ⅰ）在髁突中的含量及分布。结果：髁突各层软骨细胞均有Ⅰ型受体（ＴβＲ－Ⅰ）的分布，以成熟层阳性强度最高；功能矫形前伸下颌后，髁突软骨细胞各层ＴβＲ－Ⅰ的表达均增强。结论：机械刺激调节了ＴＧＦ－β的功能，从而促进骨的生长代谢     

脉冲电磁场对下颌前伸后髁突影响的组织学和组织化学研究

选用５周龄ＳＤ雄性大鼠２０只，随机等量地分为对照组，脉冲电磁场组（ＰＥＭＦ），功能矫治器组（ＦＡ）和ＰＥＭＦ＋ＦＡ组，研究髁突的组织学变化和细胞ＤＮＡ合成的变化。结果：①ＰＥＭＦ组和ＦＡ组均显示软骨细胞层数增多，软骨细胞变大，基质增多，在移行层与骨小梁交界处，有较多血管增生，大量红细胞出现。ＰＥＭＦ＋ＦＡ组的上述变化更为明显。②Ｂｒｄｕ阳性细胞在过渡层和成熟层较多，统计学分析表明ＰＥＭＦ组和ＦＡ组阳性细胞数均显著高于对照组，而ＰＥＭＦ＋ＦＡ组与ＰＥＭＦ组或ＦＡ组相比也有显著性差异。研究表明：ＰＥＭＦ的作用与ＦＡ类似，可使髁突软骨的ＤＮＡ合成功能活跃，促进细胞增殖，ＰＥＭＦ与ＦＡ有协同作用     

软骨细胞外泌体在大鼠颞下颌关节骨关节炎软骨异常钙化中的作用研究

目的 探索软骨细胞外泌体在大鼠颞下颌关节（temporomandibular joint，TMJ）骨关节炎（osteoarthritis，OA）退变软骨异常钙化中的作用。方法 选取48只6周龄雌性SD大鼠，根据实验时间点（2、4、8周）随机分为三大组，每大组再随机分为对照组与单侧前牙反牙合（unilateral anterior crossbite，UAC）实验组，每组8只大鼠。对UAC实验组大鼠施加UAC刺激诱导TMJ OA，于2、4、8周后分别处死各组大鼠，对TMJ髁突软骨进行CD63、基质羧基谷氨酸蛋白（matrix gla protein，MGP）的免疫组化染色和mRNA含量检测，同时透射电镜观察软骨中钙化痕迹及外泌体结构。提取大鼠TMJ髁突软骨细胞体外培养并施加流体剪切力刺激，茜素红染色检测钙化结节形成情况，对软骨细胞和外泌体蛋白进行Western Blot检测。结果 UAC实验组大鼠TMJ髁突软骨内CD63分子高表达，同时在钙化痕迹周围存在大量外泌体样结构，而MGP含量则在4周和8周时显著减少。流体剪切力可显著促进TMJ髁突软骨细胞钙化结节形成，同时外泌体数目增多，但外泌体中MGP蛋白含量显著降低。对正常培养的软骨细胞施加外泌体后可显著促进钙化结节的生成。结论 大鼠TMJ OA软骨中外泌体数目增加，同时外泌体内MGP含量降低，两方面共同促进软骨异常钙化的发生。     

转化生长因子β对白细胞介素1β诱导髁突软骨细胞凋亡的调控作用

关节软骨进行性破坏是骨关节炎 (ｏｓｔｅｏａｒｔｈｏｒｉｔｉｓ,ＯＡ)的主要病理改变之一。近来发现ＯＡ关节软骨有异常的软骨细胞凋亡 ,这可能与ＯＡ关节软骨的破坏有关。我们就ＴＧＦ β在人重组白细胞介素 1β(ｒｈＩＬ 1β)诱导髁突软骨细胞凋亡中的作用进行了研究。1 材料和方法 :( 1)ｒｈＩＬ 1β诱导软骨细胞凋亡 :将髁突软骨细胞接种于培养瓶中 ,密度为 3× 10 4/ｍｌ,培养至对数生长期 ,实验组分别加入含有ｒｈＩＬ 1β( 1、10、2 0ｎｇ/ｍｌ)及二甲基亚砜 (ＤＭＳＯ ,15μｌ/ｍｌ)的ＤＭＥＭ培养液 ,处理 8、16、2 4ｈ后收集细…     

功能矫形前伸大鼠下颌后髁突软骨β转化生长因子-1(TGF-β_1)表达变化的研究

目的：检测快速生长期大鼠髁突软骨在功能矫形前伸下颌后β转化生长因子－１（ＴＧＦ－β１）分布的变化，探讨髁突软骨生长代谢的生长因子控制机理。方法：实验组戴模拟临床功能矫治器，引导大鼠下颌前伸，并在实验后不同时期处死大鼠，取下髁突，应用免疫组织化学方法探测ＴＧＦ－β１在髁突中的含量及分布。结果：髁突各层软骨细胞均有ＴＧＦ－β１的分布，以成熟层阳性强度最高；功能矫形前伸下颌后，髁突软骨细胞各层ＴＧＦ－β１的表达均增强。结论：ＴＧＦ－β１介导了功能矫形的机械刺激作用，使软骨细胞增生，分化功能增强，髁突软骨增生     

髁状突软骨纤维组织的超微结构观察

目的：深入了解髁突内部纤维组织的结构、走行方向、相互间关系及功能。方法：用扫描电镜和透射电镜观察了8例(16侧)家兔，体重为1．5—2．0kg，月龄6个月(动物由同济医学院中心实验室提供)。颞下颌关节髁状突剖面和切削面的超微结构。结果：在扫描电镜下，剖面呈现纵横交错的立体网状结构或者类似海绵状结构；切削处可见浅层的纤细网状纤维，这种纤维与泥土样物混合交织形成软骨的外层；在网状纤维的深层可见三种粗大的纤维平行于髁状突表面走行，其直径分别约为20nm、35nm和100nm。不同部位的纤维的排列、走向不尽相同。透射电镜下，髁状突内部纤维主要是有明显周期性横纹的I型胶原。结论：①髁状突表层存在一层纤细的网状纤维。②深层纵横交错的纤维呈海绵状结构具有传导和分散压力的作用。③纤维的粗细不同可吸收各种振动频率的力，形成了对作用于颞下颌关节各种力的有效缓冲垫。④透射电镜下纤维属I型胶原，说明髁状突软骨属纤维软骨。     

冷冻电子显微镜观察人釉原蛋白的自组装

目的:采用冷冻电子显微镜(cryo TEM)体外观察人釉原蛋白的自组装过程,分析自组装各阶段蛋白的聚集状态及细微结构。方法:提取青少年下颌第三磨牙牙胚细胞总RNA,用RT-PCR获得人釉原蛋白基因全长,再与pMD19-T载体构建重组质粒,转入宿主菌E.coli Top10中诱导表达并纯化。冷冻电子显微镜观察pH值从3.5跃升至8.0时釉原蛋白发生自组装的聚合状态。结果:当pH值为8.0时在1~20 min内观察到釉原蛋白由低聚体逐步组装成多聚体、纳米球及纳米链等结构。结论:在适宜条件下,人釉原蛋白能分级组装成纳米球。     

Condylar cartilage: A scanning electron microscope study of anorganic mammalian condyles

The mandibular condyles of four mammalian species (sheep, cat, monkey, and human) were rendered anorganic in NaOCl and examined by SEM. A mineralized cartilage front was identified in all specimens on the basis of a comparable morphology of chondrocyte lacunae and a calcospheritic pattern of mineralization. Species-specific differences in the cartilage surfaces were found to exist. The role of this cartilage in condylar remodeling and pathology is discussed. Attention is drawn to the fact that mineralized cartilage was identified on the articular aspect of all adult mammalian anorganic condyles examined.     

髁状突即刻再植后的扫描电镜观察

为了解髁状突即刻再植后早期表面细微结构破坏和修复情况,本研究以日本大耳白兔为实验对象,切下右侧髁状突后行即刻再植术。术后分期处死动物,扫描电镜观察髁状突和关节盘表面细微结构的改变。结果表明术后早期术侧髁状突表面凝胶状物消失,网状胶原原纤维暴露,8周以后逐渐恢复。作者认为,髁状突再植的术式可选择性地用于颞下颌关节的重建。     

Back-scattered and secondary electron images of scanning electron microscopy in dentistry: a new method for surface analysis

Abstract

Objective. A scanning electron microscope (SEM) is a popular tool for investigating the root canal surface to visualize dentinal tubules, the smear layer and various root canal filling materials in endodontics. Most of the SEM micrographs taken in endodontic research are in secondary electrons (SE) mode, in which the topographic view of a subject can be demonstrated without giving any information about the real structure. Back-scattered electron (BSE) images are also used, which reveal some information about the internal structure while providing no topographic details. The aim of this study was to investigate the possibility of using back-scattered (BSE) and secondary electron (SE) mode of scanning electron microscopy (SEM) together for obtaining detailed information about biomaterials in relation to dental structures. Materials and methods. Mesiobuccal roots of four permanent maxillary molars were cleaned and shaped with rotary instruments. Two samples were obturated with gutta-percha and sealer. After 2 weeks, gutta-perch was removed using rotary instruments and chloroform. In the other phase of the study, white mineral trioxide aggregate was mixed and packed into five glass tubes and exposed to blood, deionized water, synthetic tissue fluid and egg white. All the samples were prepared for visualization under SE and BSE modes of SEM to observe the characteristics of material remnants and surface structures. Results. BSE mode illustrated different grey scale views which made it possible to differentiate dentin chips from filling material remnants on the surface of root canal dentin. In addition, SE mode focused on image topography, while a BSE detector showed new texture formation on the surface of white mineral trioxide aggregate exposed to proteinaceous fluids such as blood or egg white. Conclusions. Mapping BSE and SE micrographs helped us to better understand the structure of materials on the surface of root canal dentin and MTA. Moreover, analysis of structure of materials on the surface of root canal dentine and MTA can be performed better by mapping of BSE and SE micrographs.     

两种钛种植体骨界面SEM观察和电子探针元素分析

目的：研究钛种植体的两种表面形态与其骨结合界面的关系。方法：在猴下颌磨牙区分期分别植入CDIC和ITI-TPS钛种植体，对界面进行光镜、扫描电镜观察和电子探针元素分析。结果：光镜和扫描电镜观察，种植后1个月的界面只有少量的骨形成；1～3个月的ITI-TPS种植界面的骨形成较CDIC者明显；种植后1年，二者未见明显差别。元素分析，界面钛、钙、磷相互渗透，各期ITI-TPS界面钛的渗透密度均较相应时期CDIC者高。结论：埋植后1～3个月，ITI-TPS种植体骨整合性优于CDIC种植体，但随时间的延长，两种种植体均可形成良好的骨性结合界面。ITI-TPS种植体渗透至界面周围组织的钛离子多于CDIC种植体者。     

Circumferential continuity of perikymata in human dental enamel investigated by scanning electron microscopy

Abstract – Theoretically the perikymata may represent one of two possible configurations: closed circles or continuous spirals. In the present study one randomly selected perikyma groove in one randomly selected tooth (the mandibular first premolar of a 12-yr-old girl) was tracked around the circumference of the crown in the scanning electron microscope. It was found that the perikymata geometrically represented closed circles. The possibility of methodologic error was excluded.     

High resolution scanning electron microscopy of the subplasmalemmal cytoskeleton in human odontoblasts

Abstract – The subplasmalemmal cytoskeleton in human odontoblasts was studied by high resolution scanning electron microscopy. The odontoblast layer was isolated and exposed to formaldehyde, glutaraldehyde, and OsO₄ for some specimens, while the membraneous structures and soluble proteins in the dental tissue were removed by Zenker's solution and 1% OsO₄ for other specimens, without further fixation of the remaining components. The cytoskeletal elements comprised a dense network of interlacing filaments of different diameters in the cell body. Most cytoskeletal elements were parallel to the axis of the cell processes situated inside the dentinal tubules. The appearance and orientation of the investigated subplasmalemmal cytoskeletal elements was unaffected by the choice of method. Both methods confirm the presence of a subplasmalemmal cytoskeleton in human odontoblasts.     

Spatial arrangement of collagen fibrils in the articular cartilage of the mandibular condyle: A light microscopic and scanning electron microscopic study

To determine the spatial arrangement of collagen fibrils in articular cartilage of the human mandibular condyle, ten healthy condyles obtained at necropsy were examined by light microscopy and scanning electron microscopy (SEM). Observations using light microscopy showed the existence of four different zones. The organization and alignment of the collagen fibrils were different in every zone and varied from layers to bundles of fibrils running parallel, obliquely, or radially to the articular surface. Observations using scanning electron microscopy revealed a thin, surface layer of disorganized small fibrils with a cotton-wool appearance and a well-organized architecture of collagen fibrils in every zone. It was concluded that the organization of collagen fibrils in articular cartilage shows a three-dimensional network with a special system in every zone.     

Examination of six orthodontic adhesives with electron microscopy, hardness tester and energy dispersive X-ray microanalyzer

OBJECTIVE: To examine the ultrastructure of six light-cure orthodontic adhesives with scanning electron microscope (SEM) and transmission electron microscope (TEM), microhardness tester, and energy dispersive X-ray microanalyzer (EDX). MATERIALS AND METHODS: The orthodontic adhesives evaluated were Transbond XT, Light Bond, BeautyOrtho Bond, Kurasper F, Heliosit Orthodontic, and Salivatect. Specimens of each adhesive were carefully prepared for observation under SEM and TEM. Furthermore, the Vickers hardness was tested, and the adhesives were evaluated with EDX. RESULTS: SEM and TEM images illustrated great diversity of the adhesives ultrastructure. The Vickers hardness test showed significant differences among all the adhesives (except Transbond XT and Salivatect). Although some similar elements were detected with EDX, the concentration was different in each adhesive. CONCLUSION: Orthodontic brackets can be bonded to the enamel surface with the adhesives available on the market. However, orthodontists might achieve better results identifying their properties and compositions.