Advanced glycation endproducts (AGEs) induce oxidant stress in the gingiva: a potential mechanism underlying accelerated periodontal disease associated with diabetes

We hypothesized that one mechanism underlying advanced periodontal disease in diabetes may involve oxidant stress in the gingiva, induced by the effects of Advanced Glycation Endproducts (AGEs), the irreversible products of non-enzymatic glycation and oxidation of proteins and lipids which accumulate in diabetic plasma and tissue. Infusion of AGE albumin, a prototypic ligand, into mice resulted in increased generation of thiobarbituric acid reactive substances (TBARS) compared with infusion of non-glycated albumin in the gingiva, as well as in the lung, kidney and brain. Pretreatment of the animals with the antioxidants probucol or N-acetylcysteine (NAC) prevented the generation of TBARS in the gingiva. Affinity-purified antibody to AGEs demonstrated increased immunoreactivity for AGEs in the vasculature and connective tissues of the gingiva in streptozotocin-induced diabetic mice compared to non-diabetic controls. Increased immunoreactivity for AGEs was also demonstrated in the gingiva of diabetic humans compared with non-diabetic individuals via immuno-histochemistry and ELISA. Consistent with these data, immunohistochemistry for heme oxygenase-1, a marker of enhanced oxidant stress, was increased in the gingival vasculature of diabetic mice and humans compared with non-diabetic controls. These data suggest that AGEs present in diabetic gingiva may be associated with a state of enhanced oxidant stress, a potential mechanism for accelerated tissue injury.     

干燥方法对定量光导荧光系统分析早期脱矿病损的影响

目的研究不同的干燥方法对定量光导荧光系统(guantitative light-induced fluorescence,QLF)分析病损脱矿程度的影响,探讨最适合QLF临床检查使用的干燥方法.方法选择新鲜拔除的人无龋前磨牙8个,颊面用指甲油封闭留窗口大约3mm×3mm,置于脱矿液中,37℃摇床中7d形成脱矿病损.标本分别采用三种不同的干燥方法放置于空气中使之自然干燥、压缩空气干燥30s和棉卷干燥30s,然后进行QLF检查并采用盲法分析病损脱矿的严重程度.设置△Q(荧光损失量)值变化5%为病损入口,得出的数据导入SPSS 11.5软件进行统计分析.结果釉质脱矿病损随着干燥程度的增加,在QLF荧光图像中均表现为脱矿严重程度的增加.病损放置自然干燥564.386(±87.542)s后,QLF能够检测到最大荧光损失,压缩空气干燥30s和棉卷干燥30s后,能检测最大荧光损失的时间分别为39.250(±7.778)s和139.375(±13.212)s.压缩空气吹干30s后,QLF图像中病损表现出明显的荧光损失,与其他两种干燥方法有统计学差异(P＝0.000).结论压缩空气干燥30s后,病损表现的荧光损失可以用来反映该病损的最大荧光损失值.临床使用压缩空气对早期病损吹干30s是达到可靠干燥效果的最快速而实用的方法.     

˫�ഽ�ѻ򣨺ͣ�����������̷����ε���������

双侧唇裂或(和)唇腭裂一期整复后,尽管修复了唇裂或唇腭裂,但仍有诸多畸形存在,如鼻尖低平、鼻小柱短小、双侧鼻孔不等大对称、鼻翼塌陷、鼻堤缺失;上唇过紧、人中     

局麻药与奥硝唑-甲磺酸培氟沙星联用的抑菌效果

目的：探讨口腔科4种常用局麻药分别与奥硝唑-甲磺酸培氟沙星联合的抑菌效果。方法：采用琼脂纸片扩散法，检测局麻药以0、5％、10％、15％、20％体积比例与奥硝唑-甲磺酸培氟沙星液混合制备的药敏纸片所形成的抑菌环直径变化（每张滤纸片所含奥硝唑-甲磺酸培氟沙星纯药物总量一致）。结果：所有药敏纸片形成的抑菌环相互问无统计学差异（P〉0．05）。结论：4种局麻药的分别与奥硝唑-甲磺酸培氟沙星联合的抑菌效果无影响，可以混合应用。     

口腔粘膜癌前病变增殖细胞核抗原表达分布

采用免疫组化染色和图像分析技术，检测了正常口腔粘膜，轻中重度粘膜上皮异常增生和鳞状细胞癌共７４例石蜡包埋组织中增殖细胞核抗原（ＰＣＮＡ）的表达分布．结果显示，正常口腔上皮中，ＰＣＮＡ染色仅见于基层，而所有异常增生和鳞癌标本中，ＰＣＮＡ阳性反应出现在基层以上部位．从轻、中、重度异常增生到鳞癌，ＰＣＮＡ阳性细胞的比率不断增加，每个标记细胞中ＰＣＮＡ染色程度亦显著增强．表明ＰＣＮＡ表达和口腔上皮的增殖潜能及分化程度密切相关，可作为监测口腔粘膜上皮癌变风险的重要生物学标记     

大鼠磨牙牙根发育相关基因mrp1的克隆及其原核表达载体的构建

目的:从大鼠磨牙胚组织中克隆大鼠磨牙牙根发育相关基因mrp1,构建原核融合表达载体,利用大肠杆菌表达其C端肽。方法:从生后 3dSD大鼠仔鼠磨牙胚中提取总mRNA,通过RT-PCR扩增出mrp1C端肽段基因并克隆进中间载体,然后将插入基因克隆入GST融合表达载体pGEX-4T-1,以大肠杆菌DH5α为宿主菌,在 28℃下进行IPTG诱导。结果:克隆载体序列酶切鉴定、序列测定完全正确;含重组质粒的工程菌经诱导后在SDS-PAGE上出现一条新生蛋白带,Mr为 36×103,与预期C端肽Mr大小一致,约占菌体总蛋白的 19%。结论:成功地鉴定了mrp1C端肽段基因,通过基因克隆构建了其原核表达载体pGEX-4T-mrp1,并在大肠杆菌中得到了高效表达。     

Effects of transforming growth factor beta1 (TGFbeta-1) and dentin non-collagenous proteins (DNCP) on human embryonic ectomesenchymal cells in a three-dimensional culture system

Cranial neural crest-derived ectomesenchymal cells represent a population of pluripotent stem cells giving rise to many of the various oro-facial and dental tissues. The factors determining the terminal fate of these cells are still unclear. The potentiality of human embryonic ectomesenchymal cells from the first branchial arch have been investigated when isolated and grown in a three-dimensional (3D)-collagen gel culture system in the presence of dentin matrix-derived non-collagenous proteins (DNCP) and TGFbeta-1. Functional differentiation of cells showing some characteristics of odontoblast-like cells could be observed when the cells were cultured with DNCP+TGFbeta-1 or DNCP, however, only cytological differentiation was observed during culture with TGFbeta-1 alone. The characteristics of these cells was assessed by morphological appearance, expression of the odontoblast phenotype marker dentin sialophosphoprotein (DSPP), increased alkaline phosphatase levels and formation of mineralised nodules in vitro. The results indicate that these embryonic cells from the first branchial arch are capable of responding to the inductive stimulus of DNCP or DNCP+TGFbeta-1 when isolated and grown in the 3D collagen gel culture system. The capacity of the isolated cells to differentiate into mineralizing cells showing some characteristics of odontoblast-like cells under these growth conditions highlights the potential of such approaches for tissue engineering strategies for hard-tissue regeneration after injury.     

3种充填材料治疗老年人后牙根面龋临床比较

目的　选择老年人后牙根面龋充填治疗的理想材料。方法　 2 79颗患牙随机分成 3组 ,分别用银粉加强型玻璃离子、DyractAP及光固化复合树脂充填治疗 ,随访 18～ 2 4个月。结果　银粉加强型玻璃离子组的成功率为 96 .4 % ,高于光固化复合树脂组 (6 7.12 % ) ,P <0 .0 5 ,与DyractAP组 (92 .4 7% )差异无显著性 (P >0 .0 5 )。结论　银粉加强型玻璃离子治疗老年人后牙根面龋优于光固化树脂     

Smart materials in dentistry

Most dental materials are designed to have a relatively 'neutral' existence in the mouth. It is considered that if they are 'passive' and do not react with the oral environment they will be more stable and have a greater durability. At the same time, it is hoped that our materials will be well accepted and will cause neither harm nor injury. This is an entirely negative approach to material tolerance and biocompatibility and hides the possibility that some positive gains can be achieved by using materials which behave in a more dynamic fashion in the environment in which they are placed. An example of materials which have potential for 'dynamic' behaviour exists with structures which are partly water-based or have phases or zones with significant water content and for which the water within the material can react to changes in the ambient conditions. Such materials may even be said to have the potential for 'smart' behaviour, i.e. they can react to changes in the environment to bring about advantageous changes in properties, either within the material itself or in the material-tooth complex. The controlled movement of water or aqueous media through the material may cause changes in dimensions, may be the carrier for various dissolved species, and may influence the potential for the formation of biofilms at the surface. Some of these issues may be closely interrelated. Clearly, materials which do not have the capacity for water transport or storage do not have the potential for this sort of behaviour. Some materials which are normally resistant to the healthy oral environment can undergo controlled degradation at low pH in order to release ions which may prove beneficial or protective. It is doubtful whether such behaviour should be classified as 'smart' because the material cannot readily return to its original condition when the stimulus is removed. Other materials, such as certain alloys, having no means of transporting water through their structure, can display smart behaviour by undergoing predictable changes in structure in response to applied mechanical or thermal stimuli. It has been difficult to harness such behaviour to the benefit of patients but progress in this area is slowly being made.