Novel identification of a four-base-pair deletion mutation in PITX2 in a Rieger syndrome family

Rieger syndrome is one of the most serious causes of tooth agenesis. Mutations in the PITX2, FOXC1, and PAX6 genes have been associated with Rieger syndrome. We have studied a three-generation Chinese family affected with Rieger syndrome and showing prominent dental abnormalities. Mutational screening and sequence analysis of the PITX2 gene revealed a previously unidentified four-base-pair deletion of nucleotides 717-720 in exon 5 in all affected members. The mutation causes a frame shift after Thr44, the 7th amino acid of the homeo-domain, and introduces a premature stop codon in the gene sequence. This deletion is the first unquestionable loss-of-function mutation, deleting all the functionally important parts of the protein. Our novel discovery indicates that the oligodontia and other phenotypes of Rieger syndrome observed in this family are due to this PITX2 mutation, and these data further support the critical role of PIXT2 in tooth morphogenesis.     

牙龈卟啉菌荚膜的热敏感性

以细胞计数法观察了牙龈卟啉菌荚膜的热敏感性，结果显示：牙龈卟啉菌荚膜在５０℃下，水浴３０ｍｉｎ，活性基本不受影响，６５℃水浴３０ｍｉｎ半量活性成份丧失，８０℃水浴３０ｍｉｎ活性完全丧失，说明牙龈卟啉菌荚膜是一热不稳定性物质。     

Parry-Romberg syndrome combined with hemifacial spasm: association or chance event?

Parry-Romberg syndrome or progressive facial hemiatrophy is a rare clinical entity of an unknown etiology. We present the case of a 57-year-old Chinese woman with Parry-Romberg syndrome and hemifacial spasm both on the right side. Its association was not reported before. In our report of Parry-Romberg syndrome with hemifacial spasm, we try to explore whether there were some relations between the 2 diseases. We found an offending vessel compressing the root exit zone of the facial nerve and no evidence of vessel compression at ipsilateral trigeminal nerve motor rootlet.     

Synthesis and preparation of novel 4-arm star-shape poly(carboxylic acid)s for improved light-cured glass-ionomer cements.

OBJECTIVE: The objective of this study was to synthesize and characterize novel 4-arm star-shape poly(acrylic acid)s (poly(AA)s) via atom-transfer radical polymerization (ATRP) technique, tether in situ light-curable methacrylate functionalities onto the poly(AA) backbone, use these star-shape poly(AA)s to formulate the light-cured glass-ionomer cements (LCGICs), and evaluate the mechanical strengths of the formed cements. MATERIALS AND METHODS: The 4-arm poly(AA)s were synthesized using ATRP and tethered with either 2-isocyanatoethyl methacrylate (IEM) or glycidyl methacrylate (GM). The polymers were formulated with 2-hydroxyethyl methacrylte (HEMA) or methacryloyl beta-alanine (MBA), water, initiators, and Fuji II LC filler. Compressive strength (CS) was used as a tool to evaluate the formed cements. The specimens were conditioned in distilled water at 37 degrees C for 24h prior to testing. RESULTS: The 4-arm poly(AA) showed a lower viscosity as compared to its linear counterpart. Both IEM-tethered and GM-tethered 4-arm poly(AA) constructed LCGICs showed significantly high mechanical strengths. Both types of co-monomer and grafting agent dramatically affected the mechanical strengths. The MBA-containing poly(AA) cements exhibited much higher CS than the HEMA-containing cements. The IEM-tethered poly(AA) cements showed much higher CS and DTS than the GM-tethered cements. CONCLUSIONS: This study developed a novel light-curable 4-arm star-shape poly(AA) system. The system was 13% in CS, 178% in DTS and 123% in FS, compared to Fuji II LC.     

建立下颌前牙牙槽骨吸收和联冠修复的三维有限元模型

目的：建立下颌前牙不同程度牙槽骨吸收后的釉质、牙本质、牙骨质、牙周膜、松质骨、皮质骨等组织的三维有限元模型。方法：利用薄层CT扫描技术与Ansys软件相结合，对层厚为1mm的CT断层影像进行分析处理。结果：模型具有良好的几何相似性，共有单元约13万个，节点约19万个，数据量约130MB，可以根据要求任意旋转、缩放、透视、剖开，进行多种方式观察；并可以按照不同研究目的和要求，对模型进行简单的修改和调整，模拟牙槽骨吸收、联冠修复等临床治疗所需的几何形态，考查各种约束和加载条件下前牙的力学反应；讨论了约束的处理和载荷的施加方式。结论：薄层CT扫描技术与Ansys软件相结合建立的三维有限元模型，能较精确地模拟实际情况，为进一步研究下颌前牙牙槽骨吸收和联冠修复奠定了良好的基础。     

口腔颌面部血管瘤激素治疗的疗效评价

国内外应用类固醇激素治疗口腔颌面部血管瘤疗效报道不一致,在很大程度上与传统分类方法紊乱有关。本研究采用血管瘤和血管畸形的新分类,对31例血管瘤进行口服强的松治疗。根据服药后病变改变大小、颜色深浅变化将疗效分为优、良、中、差。服药前采用放射免疫方法进行血清Es水平测定,来探讨其疗效与血清E2之间的关系。结果表明:口服强的松治疗血管瘤的有效率为74％。强的松疗效优、良、中、差各组间的血清E2水平无显著差异(P>0.05),说明强的松疗效好坏与血清E2水平无关。     

烧结次数对金属烤瓷冠强度的影响

目的:通过金属烤瓷冠的破坏试验,研究烧结次数对金属烤瓷冠强度的影响.方法:用Instron万能材料测试机对不同烧结次数金属烤瓷冠试件进行破坏试验,测试其折裂时的力值,并对破坏试验力值进行统计分析.结果:不同烧结次数金属烤瓷冠的破坏试验力值差异有显著性(P＜0.01),烧结4次和6次组的破坏试验力值均分别大于烧结8、10、12次组(P＜0.01),但烧结4、6次组间及烧结8、10、12次组间的破坏试验力值差异无显著性(P＞0.05).结论:超过一定的烧结次数时,烧结次数的增加对金属烤瓷冠的强度有影响.烧结4～6次时金属烤瓷冠的强度最大,随烧结次数的增加,当烧结超过8次时,金属烤瓷冠的强度降低.在满足临床需要的前提下,应尽量减少金属烤瓷冠的烧结次数,最好控制在8次以下.     

Ion transfer reactions in media of low ionic strength

Facilitated ion transfer (FIT) and simple ion transfer (IT) reactions at the water|1,2-dichloroethane (W|DCE) interface with media of low ionic strength are investigated by employing micro- and nano-pipettes. The model systems chosen for the FIT and IT are K⁺ transfer facilitated by dibenzo-18-crown-6 (DB18C6) and tetramethylammonium (TMA⁺), respectively. For the FIT reaction at micro- and submicro-liquid|liquid interfaces, when the supporting electrolyte concentrations in the organic phase are at micromolar levels, its voltammetric waves are analyzed by the theory for one-electron oxidation of uncharged species in organic solution with little added supporting electrolyte on solid ultramicroelectrodes (UMEs) proposed by Oldham [K.B. Oldham, J. Electroanal. Chem. 250 (1988) 1]. Its chronoamperograms are strongly affected by the externally applied potentials, which is consistent with the theory proposed by Stojek and co-workers [A. Jaworski, M. Donten, Z. Stojek, Anal. Chim. Acta 305 (1995) 106, A. Jaworski, M. Donten, Z. Stojek, J. Electroanal. Chem. 407 (1996) 75, W. Hyk, M. Palys, Z. Stojek, J. Electroanal. Chem. 415 (1996) 13, W. Hyk, Z. Stojek, J. Electroanal. Chem. 422 (1997) 179] for reactions at solid UMEs with different concentrations of supporting electrolyte. In addition, the FIT reaction can exhibit well-defined steady-state waves at the nano-liquid|liquid interface when no supporting electrolyte is added to the organic phase. For the TMA⁺ transfer reaction from the aqueous phase to DCE (or from DCE to the aqueous phase), the magnitude of its steady-state limiting current depends on the concentration of supporting electrolyte in the same phase, and the shape and position of its transfer waves are influenced by the supporting electrolyte concentrations in the adjacent phase. We can observe clearly the migration effect on the transfer reaction of charged species.     

MDIC种植体颧骨种植在全上颌骨缺损功能重建中的应用

目的 :研究MDIC种植体在颧骨种植重建全上颌骨缺损的方法及临床效果。方法 :6例肿瘤治疗后全上颌骨缺损的患者 ,应用MDIC种植体在颧骨种植 ,通过种植修复体进行上颌骨缺损功能重建。结果 :重建后患者的面形明显改善 ,修复体固位良好 ,发音及咀嚼功能得到很好的恢复 ,植入的种植体可以实现骨结合并完成种植修复 ,行使功能。结论 :此方法可以实现全上颌骨缺损的功能重建。     

小鼠牙胚发育过程中collagenⅠ/Ⅲ的表达分布

目的:探讨collagenⅠ、Ⅲ在Balb/c小鼠牙胚发育各期的时间和空间分布特点,及两者在牙齿发育矿化中的作用。方法:用免疫组化方法检测小鼠牙胚发育各期collagenⅠ、Ⅲ的表达、分布。结果:collagenⅢ:出生前E13d小鼠牙胚蕾状期:口腔上皮细胞阳性表达( );E14~17d帽状期:口腔上皮细胞、成釉器星网层细胞表达弱阳性;E18~19d和出生后P1d钟状期与分化期:口腔上皮细胞、成釉器星网层细胞、牙乳头细胞、牙囊细胞表达阳性( );出生后P2~10d牙冠发育成熟期:成釉细胞、釉基质、成牙本质细胞、前期牙本质、牙乳头细胞、牙囊细胞、牙髓组织等均表达阳性( );P10~30d牙根发育成熟期:除上述细胞成分外,上皮根鞘、根周及根尖牙槽骨、牙骨质和牙周膜表达强阳性( )。collagenⅠ:在蕾状期无表达;帽状期:口腔上皮细胞、成釉器星网层细胞表达阳性;钟状期与分化期:口腔上皮细胞、成釉器星网层细胞、牙乳头细胞、牙囊细胞表达阳性;牙冠和牙根发育期:其分布和表达类似于collagenⅢ。结论:鉴于collagenⅠ、Ⅲ的表达和分布,表明它们均参与了牙胚和牙体硬组织的发育形成,但似乎cllagenⅢ的作用比collagenⅠ更为广泛。