腺病毒介导HSV-TK/GCV系统治疗舌癌的实验研究

目的　探讨腺病毒介导单纯疱疹病毒胸苷激酶基因 (herpessimplexvirusthymidinekinase,HSV TK) /丙氧鸟苷 (ganciclovir,GCV)自杀基因系统对舌鳞癌细胞系的治疗作用。方法　RT PCR检测重组腺病毒感染Tca8113舌鳞癌细胞系后TK基因的表达情况 ;MTT法检测HSV TK/GCV系统对舌癌细胞的杀伤作用及旁观者效应。结果　AdCMVHSV TK可在舌癌细胞中表达TK基因并具有高转染率 ;HSV TK/GCV系统对舌癌细胞具有杀伤作用 ,杀伤呈时间和剂量依赖性 ;但该系统的旁观者效应差。结论　HSV TK/GCV自杀基因系统对舌鳞癌细胞系具有一定的杀伤作用     

HSV-TK自杀基因对涎腺多形性腺瘤细胞治疗的实验研究

目的研究单纯疱疹病毒胸苷激酶基因(Herpes simplex virus thymidine kinase，HSV-TK)／丙氧鸟苷(ganciclovir，GCV)系统对人涎腺多形性腺瘤体外基因治疗的作用。方法采用腺病毒包装重组脂质体介导的含有HSV-TK全长的cDNA真核表达质粒PDC312-HSVTK转染人涎腺多形性腺瘤细胞，通过RT-PCR检测TK基因在转染细胞中的表达；用MTT法检测HSV-TK／GCV系统对多形性腺瘤细胞的杀伤作用和旁观者效应：采用倒置显微镜、组织学染色等观察HSV-TK／GCV系统作用细胞后的形态学改变。结果HSV-TK基因转染24小时后，肿瘤细胞开始出现空泡性变；转染48小时后，RT-PCR从转染的细胞中成功扩增出1150bp的特异性TK基因片段。转染36小时后加入不同浓度的GCV治疗，细胞出现核固缩，胞浆裂解，随之细胞死亡、脱壁的现象。细胞存活率随HSV-TK／GCV作用时间延长而逐渐下降，当加入10^-4mol／LGCV治疗7天时，HSV-TK／GCV系统的杀伤作用最强，细胞存活率为10．3％。当TK阳性的细胞占细胞总数50％时，其旁观者效应最明显，细胞存活率为31．7％。结论HSV-TK／GCV系统对涎腺多形性腺瘤细胞具有明显的杀伤作用和旁观者效应。     

HSV-tk与p53基因对涎腺多形性腺瘤细胞的杀伤作用

目的　观察腺病毒介导的单纯疱疹病毒胸苷激酶(HSV-tk)基因、野生型p53基因(wt-p53)联合杀伤人涎腺 多形性腺瘤细胞的效果。方法　采用腺病毒介导的HSV-tk基因、wt-p53基因联合转染人涎腺多形性腺瘤细胞,逆 转录聚合酶链式反应(RT-PCR)检测转染后的基因表达;四唑盐比色(MTT)法测定tk与p53基因治疗后对肿瘤细 胞的杀伤作用及旁观者效应,并采用相差显微镜观察基因治疗后肿瘤细胞的形态学变化。结果　单独转染wt-p53 及HSV-tk/GCV基因5 d后,涎腺多形性腺瘤细胞的存活率分别为54%和38%;两者联合转染5 d后,细胞的存活率 降至20%,两者差异有显著性(P<0.05)。结论　HSV-tk、wt-p53基因联合应用对涎腺多形性腺瘤的杀伤作用强于 此两基因单独应用的杀伤作用。     

8-Br-cAMP提高HSV-TK/GCV自杀基因系统旁观者效应的研究

目的 探讨8-Br-cAMP对单纯疱疹病毒胸苷激酶（HSV-TK）/丙氧鸟苷（GCV）系统旁观者效应的增强作用及机理。方法 应用FCM、透射电镜检测8-Br-cAMP对口腔鳞癌细胞（Tca8113）、间隙连接蛋白43（Cx43）及间隙连接的诱导分化作用;采用析因分析法分析8-Br-cAMP对HSV-TK/GCV系统旁观者效应的影响。结果 口腔鳞癌细胞经 10-4mol/L 8-Br-CAMP处理后:FCM检测显示 Cx43表达阳性的细胞由治疗前的（4.8 ± 0.26）％上升到（21.3±0.65）％,两组比较P<0.001;透射电镜显示细胞超微结构出现分化,细胞间出现间隙连接;MTT检测显示增强了HSV-TK/GCV系统治疗时的旁观者效应,两者间存在协同关系。结论8-Br-cAMP可诱导分化口腔鳞癌细胞并显著提高HSV-TK/GCV系统治疗时的旁观者效应。     

自杀基因系统HSV1-TK/GCV对MEC-1细胞的体外杀伤及诱导凋亡作用

目的：探讨HSV-TK／GCV系统对MEC-1细胞的体外作用。方法：用脂质体介导将含有HSV1-TK全长cDNA的真核表达质粒G1NATK转染人黏液表皮样癌细胞系MEC-1，经G418筛选，挑选阳性克隆，用PCR及RTPCR检测目的基因的整合及mRNA转录；分别用MTT及细胞记数法检测TK阳性细胞对GCV的体外敏感性及旁观者效应；用倒置显微镜、HE染色、活细胞荧光染色及TUNNEL染色观察GCV作用下MEC-1／TK的形态学变化。结果：PCR及RT-PCR分别从G418阳性克隆中成功扩增出404bp的特异性基因片段，将此G418抗性克隆命名为MEC-1／TK；IC50MEC-1／TK为0．7μg／m1，而MEC-1为1000μg／m1以上；当将TK阳性细胞和TK阴性细胞以不同比例混合，TK阳性细胞只占10％时，即有90％的细胞被杀死；形态学观察表明，经GCV作用，MEC-1／TK细胞变圆、脱壁、漂浮，部分细胞呈现核浓缩、核碎裂等特征，TUNNEL染色核阳性着色细胞明显增多。结论：HSV-TK／GCV系统在体外能明显杀伤MEC-1细胞，对GCV的敏感性比未转染的亲本细胞提高1000倍以上，并显示较强的旁观者效应；GCV可诱导部分MEC-1／TK细胞发生凋亡。     

腺病毒介导CD/5-FC系统治疗舌癌的实验研究

目的:探讨胞嘧啶脱氨酶基因/5-氟胞嘧啶(CD/5-FC)自杀基因治疗系统对舌癌细胞株的治疗效果。方法:应用透射电镜、RT-PCR检测含CD基因的重组腺病毒(AdCMVCD)对舌癌细胞株Tca8113的转染及表达情况,MTT法检测AdCMVCD/5-FC系统对舌癌细胞的杀伤作用及旁观者效应,FCM检测该系统对舌癌细胞周期的影响。结果: AdCMVCD可转染入舌癌细胞的胞核并表达CD基因;AdCMVCD/5-FC系统对舌癌细胞具有强杀伤作用和旁观者效应;FCM检测结果显示舌癌细胞S期比率显著升高(P<01001),G2+M期比率下降为0(P<01001),G1/G0期的改变不明显(P>0105)。结论:AdCMVCD/5-FC自杀基因系统对舌癌细胞株具有强的杀伤作用,杀伤作用具有细胞周期 (S期)特异性。     

纤维粘连蛋白对人涎腺腺样囊性癌细胞株侵袭和转移的影响

为了研究纤维粘连蛋白（FN）与人涎腺腺样囊性癌（Acc）转移的关系，本研究应用免疫组织化学染色，Boyden小室体外移动试验和体外粘附试验，对人涎腺腺样囊性癌细胞系ACC—2和从其克隆出的高转移细胞株ACC—M细胞进行比较研究。结果发现FN在ACC—M表达明显高于ACC—2。在加入外源性FN后，ACC—2体外移动性、粘附率均明显提高，已接近ACC—M，而ACC—M无明显变化。结果表明FN在Acc侵袭和转移中起重要的调节作用。     

神经生长因子对体外培养腺样囊性癌细胞的作用

目的研究神经生长因子(nervegrowthfactor,NGF)对体外培养的腺样囊性癌(adenoidcysticcarcinoma,ACC)细胞的作用及其机制。方法使用四甲基偶氮唑蓝(MTT)法检测不同浓度NGF(0.0,0.1,1.0,10.0,100.0,200.0ng/ml)对体外培养的腺样囊性癌细胞系Acc-2和Acc-M的作用;使用反转录(RT)-PCR检测两株细胞系中NGF的受体TrkA和p75的表达。结果Acc-2和Acc-M细胞中各浓度组的吸光度值和对照组差异均无显著性(P>0.05)。指数增长期的两株细胞内在mRNA水平均未发现TrkA和p75基因的表达。结论体外培养的腺样囊性癌细胞不表达NGF的受体TrkA和p75。NGF对体外培养的腺样囊性癌细胞的增殖无明显的促进或者抑制作用。     

骨形态发生蛋白-2基因转染对舌癌细胞增殖活性的影响

目的 探讨腺病毒介导的人骨形态发生蛋白-2 (BMP-2)基因转染舌癌Tca8113细胞后,对Tca8113细胞形态和增殖活性的影响.方法 分别以感染复数(MOI)为0、50、100的腺病毒为载体的BMP-2基因转染体外培养的舌癌Tca8113细胞.采用荧光倒置显微镜观察转染前后Tca8113细胞形态的变化,Weste...     

骨形态发生蛋白-2基因转染对舌癌细胞增殖活性的影响

分别以感染复数(MOI)为0、50、100的腺病毒为载体的BMP-2基因转染体外培养的舌癌Tca8113细胞。采用荧光倒置显微镜观察转染前后Tca8113细胞形态的变化,Western blot法检测Tca8113细胞BMP-2的表达,四甲基偶氮唑盐(MTT)法检测Tca8113细胞增殖能力,并绘制生长曲线。结果:MOI为100时转染率最高,转染前后Tca8113细胞形态变化不大,Western blot检测到Tca8113细胞BMP-2的表达,转染后Tca8113细胞的增殖活性降低。结论:腺病毒介导的人BMP-2在体外能够抑制舌癌Tca8113细胞的增殖活性。     

不同剂型玻璃离子水门汀溶解性比较研究

目的:研究、比较不同剂型玻璃离子水门汀的溶解性和表面微观形态改变,为临床使用提供依据.方法:将3M树脂加强型玻璃离子水门汀(水粉剂型)、GC玻璃离子水门汀(水粉剂型)及GC玻璃离子水门汀(双糊剂型)分别在人工唾液中浸泡30 d,冷热循环15000次,烘干测重,比较前后质量变化,计算溶解率,并用扫描电镜观察表面微观改变.结果:不同剂型的玻璃离子水门汀溶解率由高到低分别为3M树脂加强型玻璃离子水门汀(水粉剂型)、GC玻璃离子水门汀(水粉剂型)、GC玻璃离子水门汀(双糊剂型).3种玻璃离子水门汀经浸泡溶解后,SEM扫描表面微观形态可观察到GE玻璃离子水门汀(双糊剂型)表面形态改变较少,其他2组玻璃离子水门汀表面微观改变较多.结论:双糊剂型玻璃离子水门汀理化性能及溶解率均低于传统水粉剂型,是未来临床修复治疗的的良好选择.     

Evidence of the validity of a model of determinants of quality of restorative dental care

A model describing the relationship between self-reported quality of restorative dentistry and dentist characteristics for 119 Montana general dentists is presented. The best predictors formed a significant model explaining 22% of the variance of the quality measure. Results are contrasted with a previous estimation of the model for 102 Washington general practitioners. Evidence for the external validity of the model is presented.     

Design of clinical trials of traditional therapies of periodontitis

The present paper on the design of clinical trials of periodontal therapy first addresses the issue of the etiology of periodontal disease. It is suggested that most if not all forms of destructive periodontal disease are caused by microorganisms and that there are different forms of disease with different microbial etiologies. The progressive nature of destructive periodontal disease is subsequently discussed and it is emphasized that, in a given patient, periodontal sites which show signs of inflammation and attachment loss may not over a period of several months and years show further sign of attachment loss. The present methods of assessing periodontal disease do not allow us to discriminate between potentially active and inactive sites in untreated patients. The significance and variability of indicators of periodontal disease such as bleeding on probing, probing pocket depth and probing attachment level measurements are discussed. The errors inherent in the various measurements are analyzed and suggestions are presented describing how alterations in any of the above parameters could be identified and presented in a clinical trial. Of concern for the statistical analysis of clinical data of periodontal disease is the definition of the "experimental unit". For a number of years, the "experimental unit" in periodontal trials was the patient. It is clear, however, that different sites within the same individual show different patterns of disease progression and lesion morphology and often respond differently to periodontal therapy. Statistical analyses must consequently be designed which recognize differences in site-to-site infection and lesion morphology within a common host. Until such analyses are available, the investigator should be wary of pooling data within the same individual, since such pooling may obscure meaningful alternatives which may take place in individual periodontal sites. Some goals of periodontal therapy are subsequently identified. 4 goals are discussed more in detail, namely: to establish conditions which will allow the patient to maintain a dentition without further breakdown of the periodontium; to reduce pocket depth to establish an anatomy in the dentogingival region which with proper maintainance care will prevent the re-establishment of the subgingival infection; to gain attachment as a result of treatment; to assess the effect of a certain chemotherapeutic agent on periodontal disease.     

Experimental evidence of formation of imines in the course of reduction of hydrazones

The reduction of hydrazones is generally suggested to proceed through a reductive cleavage of the nitrogen–nitrogen bond followed by a reduction of the carbon–nitrogen bond. This sequence of reduction processes is here supported for fluorenone (V) and benzophenone (VI) hydrazones as well as by a comparison of the reduction of fluorenone and benzophenone hydrazonium ions (I,III) with corresponding imines (II,IV). Another proof of the presence of imines as intermediates is the splitting of four-electron waves of hydrazones V and VI and hydrazonium ions I and VIII into two waves at pH < 2. This has been interpreted as due to differences in slopes dE_1/2/dpH and pK_a-values of protonated hydrazine derivatives on one side and corresponding imines on the other. In this pH-range imines formed in reductions of VI and VIII are reduced in a single two-electron wave, those of I and V in two one-electron steps. Fluorenone imine (II) is sufficiently stable to allow recording of time-independent current–voltage curves between pH 6 and 11. In this pH-range the imine (II) is reduced in two one-electron steps. Benzophenone imine (IV) has been found stable between pH 4.6 and 12. At pH 4.6–8 the reduction of the imine IV takes place in a single two-electron step, at pH 8–12 in two one-electron steps. Final proof of the initial cleavage of the N–N bond is presented by comparison with the reduction of nitrones.     

Evaluation of efficacy of chemiluminescence for diagnosis of leukoplakia

ObjectiveLeukoplakia is the most common potentially malignant disorder preceding oral cancer. Chemiluminescence has been developed as an adjunct to conventional examination for the diagnosis of these potentially malignant disorders. This study was conducted to assess the efficacy of chemiluminescence in the diagnosis of leukoplakia and to compare the results with histopathological examination.Study designA total of 50 patients with leukoplakia were included from the outpatients attending the Department of Oral Medicine and Radiology, Dental Hospital, Bengaluru, Karnataka, India. These patients were subjected to conventional oral examination followed by chemiluminescent examination with Vizilite (Zila, Fort Collins, CO, USA) and biopsy for histopathological confirmation.ResultsThe sensitivity, specificity, positive predictive value, and negative predictive value of chemiluminescence were 93.75%, 55.56%, 78.95%, and 83.3%, respectively. The overall accuracy of chemiluminescence was 80%. A statistically significant association was observed between histopathology results and chemiluminescence results.ConclusionAlthough it is an easy, safe, minimal time consuming, and noninvasive technique, it has only adjunctive utility and it does not replace biopsy for the diagnosis of leukoplakia.     

正常青年Monson球面半径的测量研究

目的测量正常青年Monson球面半径。方法选择60名(男30名,女30名)正常青年制取全口印模,应用立体摄影成像的原理与方法对Monson球面半径进行测量和统计学处理。结果Monson球面的半径平均为10.173 cm,大于理论值10.160 cm,差异有显著性(P<0.01);男、女性球面半径差异无显著性。结论本实验所得到的数据可作为全口义齿修复中记录颌位关系的一个参量。     

Electrodeposition of bilayers of dithiols

We report an electrochemical method to form a bilayer of dithiol. The cyclic voltammogram of the oxidative deposition of an aromatic dithiol on gold from an alkaline aqueous solution reveals two current peaks separated by more than 400 mV. The integrated charge of the oxidative current peak (B) at the most positive potential is twice that of the other oxidative current peak (A). These two oxidative current peaks were characterized by differential capacitance and electrochemical quartz crystal microbalance (EQCM) measurements. A decrease of the capacity by a factor of two, and an increase of the EQCM frequency change by a factor of two were observed when the potential was scanned from a value where only the first oxidative peak (A) is obtained, to a potential where both oxidative current peaks (A and B) are obtained. Infrared spectra show that the aromatic dithiols adsorb vertically at potentials corresponding to the current peak A and they become tilted for potentials corresponding to the current peak B. The simple relationships between the properties of the two oxidative current peaks are found to be compatible with a step-wise oxidative deposition of a bilayer of dithiol.     

正畸患者切牙影像失真发生情况分析

目的研究正畸患者曲面体层片上的切牙影像失真发生情况，并分析其原因。 方法从中山大学附属口腔医院放射科影像数据库中选取500例正畸患者的曲面体层片和头影测量侧位片，所有曲面体层片均采用咬合杆投照，分别从切牙牙体影像放大、缩小、牙根变短、根尖模糊等评价指标分析上下颌切牙影像失真的发生情况，在头影测量侧位片上测量中切牙根尖-对颌切牙切缘的距离，探讨切牙影像失真发生的原因。采用SPSS 19.0统计软件对所得数据进行统计学检验。 结果500例患者中，切牙牙体影像正常者共417例，切牙牙体影像失真者共83例，影像失真发生率16.6%，其中切牙牙体影像放大17例、牙体影像缩小0例、牙根变短30例，牙根影像变短伴模糊36例。影像失真患者的根尖-切缘距离大于影像正常的患者，差异有统计学意义（F = 5 187.18，P = 0）；影像失真患者的覆盖值大于影像正常的患者，差异有统计学意义（F>477，P = 0）。 结论严重牙颌面畸形如反 、深覆盖是导致曲面体层片的切牙影像失真的主要原因之一。     

颌骨动静脉畸形的栓塞治疗

目的：总结直接穿刺结合经血管内介入栓塞治疗颌骨动静脉静脉畸形的经验。方法：收治凳骨动静脉畸形患者6例,均进行了介入栓塞治疗。采用的栓塞材料为附凝血棉纤毛的螺圈,聚乙烯醇泡沫微粒和二氰基丙烯酸对丁酯。数字减影颈动脉造影在PHILIPSV300下完成。结果6例颌骨动静脉畸形患者中4,例急性出血得到了快速、有效控制,1例慢性渗血的右下 骨动静脉畸形患者,介入栓塞治疗,拔除松动的右下凳第一磨牙,有效地控制了出血,另1例伴局部软组织搏动性膨隆的上凳骨动静脉畸形患者,介入治疗后膨隆的搏动性得到明显改善,栓塞治疗后分别随访3－24个月,均未发现有口腔内渗血或出血。随访的X线片上,病灶区可见新骨形成。结论：局部穿刺结合经血管内介入栓塞治疗颌骨动静畸形是一种安全、有效的治疗方法。