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.     

创伤性面瘫物理疗法的临床研究

目的 比较超短波加离子导入疗法（A组）与电刺激加离子导入疗法（B组）治疗创伤性面瘫的效果。方法 对39例创伤性面神经损伤患者进行临床对照研究，通过量化面神经功能评价、神经电图检查及面神经功能的主观评价比较面神经损伤的治疗效果。结果 创伤性面瘫以青年男性多见，损伤程度以中、重度为主；对于神经损伤轻、中度患者,A组与B组均能促进神经恢复，B组神经功能开始恢复时间早于A组。对于神经损伤重度患者，A组与B组神经恢复率高于对照组，两组均不能减少并发症出现率。结论 超短波加离子导入疗法与电刺激加离子导入疗法均能促进面神经损伤的恢复，但对于减少并发症发生率并无帮助。     

用傅立叶变换红外光谱仪研究复合树脂的双键转化度

为了研究牙科复合树脂的聚合，采用傅立叶变换红外（Ｆｏｕｒｉｅｒｔｒａｎｓｆｏｒｍｉｎｆｒａｒｅｄ，ＦＴＩＲ）光谱仪测定８种牙科复合树脂的双键转化度并比较了压片制样法和薄膜制样法对转化度的影响。结果发现，树脂的双键转化度在４５％～７４％之间；可见光固化树脂的转化度高于化学固化树脂者。在光固化树脂中，混合填料树脂的转化度高于超微填料树脂者，粘接辅助剂的转化度最高。对光固化树脂而言，压片制样法所测得的转化度值高于用薄膜制样法；而在化学固化树脂，用二种制样方法所测得的转化度值相同。本研究结果可供临床应用复合树脂参考。     

变形链球菌CH43变链素Ⅰ基因片段的克隆及表达

目的:获得编码变形链球菌CH43变链素Ⅰ前体肽基因片段,并诱导其在不杀伤工程菌的前提下高效表达。方法:用PCR技术从变形链球菌CH43基因库中扩增出编码变链素Ⅰ成熟肽mutA基因片段相应大小的DNA片段,将片段与pMD18 T载体连接后测序。将测序正确的mutA按照BamHⅠ和HindⅢ酶切位点克隆入原核表达载体pProEX,将连接产物转化入E.coliDH5α,挑出阳性克隆,IPTG诱导表达重组的6×His融合蛋白。以IPTG浓度、A600值、诱导时间各梯度优化表达。结果:PCR获得的mutA序列与GenBank报道的一致(为147bp)。优化了诱导条件使重组载体在E.coliDH5α中高效表达,融合蛋白经SDS PAGE,在相对分子质量为5. 7×103处有特异的蛋白条带,在A600为1. 666时,加入IPTG至终浓度为1. 0mmol/L,诱导6h,目的蛋白表达量最高,占菌体总蛋白量的20%左右。结论:成功克隆变形链球菌CH43变链素ⅠmutA基因片段,并在E.coliDH5α中高效表达。     

Dental caries and chemical warfare within the mouth

To date, it appears that the dentists' war against dental caries has no end in sight due to the fact that dentists lack any genuine offensive firepower. Make no mistake, the defense has drastically improved as dentists have shifted the focus more toward the preventive aspects of dental care. But defense by itself cannot defeat the enemy; at best, it can maintain the status quo. In order to defeat the enemy, one must study and understand the enemy, to know its strengths and weaknesses, and to strike at those points of vulnerability. The aim of this research is to identify and characterize genes that are responsible for observed virulence factors in Streptococcus mutans, which is the primary pathogen involved in the development of dental caries. Once there is a more defined understanding of the many virulence factors of S. mutans, there will be a much more valuable insight into its role in the ecology of the oral cavity. Eventually, this knowledge could enable dentists to convert the bacterial "weaponry" into its own arsenal, which could then be innovatively employed as preventive, diagnostic, and therapeutic agents to treat oral bacterial-related diseases.     

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.     

Validation of DIAGNOdent for quantification of smooth-surface caries: an in vitro study

The aims were 1) to validate a laser-based device, KaVo DIAGNOdent, for quantification of caries lesions on smooth surfaces, using histopathologic and microradiographic analyses as the gold standard, and 2) to test inter- and intra-observer agreements. We also investigated the influence on DIAGNOdent readings of the storage medium used for extracted teeth. Two observers measured independently the tooth surfaces of 40 extracted premolars that had been stored in thymol-saturated saline. After subsequent storage in neutral-buffered formalin for 14 days they were re-measured. The teeth were then sectioned for histopathologic and microradiographic analysis. The Spearman rank correlation coefficients between lesion depth and DIAGNOdent readings were 0.78-0.83 and 0.85 for teeth stored in thymol-saturated saline and formalin, respectively. Inter- and intra-observer agreements were 0.94 and 0.95 when the teeth were stored in thymol-saturated saline. The DIAGNOdent reading was almost 1.5 times higher for teeth stored in formalin than for those stored in thymol saline. The Spearman rank correlation coefficient between mineral loss in enamel (deltaZ) and DIAGNOdent readings ranged from 0.64 to 0.68. It was concluded that DIAGNOdent may be helpful for assessing smooth-surface caries, but the cut-off points need to be assessed under clinical conditions. The increase in fluorescence associated with storage of teeth in formalin warrants further investigation.     

颌面部巨大血管畸形的放射治疗

目的 分析颌面部巨大血管畸形的临床特点及治疗方法,探讨放疗在血管畸形治疗中的可行性.方法 回顾分析2000年1月至2008年1月浙江大学医学院附属第二医院施行三维立体定向适形放射治疗的颌面部巨大血管畸形6例的临床资料,并主要根据影像检查与临床体检结果判断疗效.结果 6例患者在术中、术后无严重并发症,均对治疗后面部外形满意,MRI示病变范围缩小,甚至消失.随访0.5～9年,6例患者均无明显复发迹象.无一例出现视器损伤、张口受限等放疗并发症.结论 三维立体定向适形放疗可以作为一种安全有效治疗颌面部巨大血管畸形的方法.

Abstract：

Objective To discuss the clinical use of radiotherapy in the treatment of giant vascular malformation. Methods Six patients with giant vascular malformation in oral and maxillofacial region were treated by three dimensional radiation therapy in Department of Stomatology, The Second Affiliated Hospital,School of Medicne, Zhejiang University in the last ten years and the cilinical data were reviewed. The treatment results were evaluated by clinical examination and radiology. Results No complication was observed during and after the radiotherapy. All patients were satisfied with the aesthetic results. The lesions in MRI were all reduced and even disappeared. There was no sign of recurrence during the follow-up period.Conclusions Three dimensional radiotherapy is safe and effective for oral and maxillofical vascular malformation.