高温诱导颊癌细胞凋亡的相关机理研究

目的 :探讨热诱导BcaCD885细胞凋亡的分子机理。方法 :水浴加温诱导BcaCD885产生凋亡。通过FCM DNA、FCM 抗体检测技术 ,观测热诱导颊癌细胞凋亡过程中bcl- 2及bax基因蛋白表达的动态变化。结果 :凋亡率与bcl- 2蛋白表达水平存在负相关关系 ,与bax蛋白表达水平存在正相关关系。结论 :高温作为一种外来刺激信号通过下调bcl 2基因的表达、上调bax基因的表达、上调bax基因的表达 ,诱导BcaCD885细胞凋亡的发生     

硫代反义Bcl-xL寡脱氧核苷酸对BcaCD885颊癌细胞凋亡及热敏感性的影响

目的　探讨硫代反义Bcl-xL寡脱氧核苷酸(AS-sODN)对BcaCD885颊癌细胞凋亡及热敏感性的影响。方法　以脂质体Lipofectin为载体,转染AS-sODN于BcaCD885细胞内,倒置显微镜观察细胞形态学改变,TUNEL原位末端标记检测细胞凋亡,流式细胞技术(FCM)测定细胞凋亡率及Bcl-xL蛋白表达水平;转染AS-sODN于BcaCD885 细胞内,再以43℃,40 min加热细胞,FCM检测细胞凋亡率。结果　AS-sODN转染后,BcaCD885颊癌细胞出现皱缩、呈浮起状,TUNEL原位末端标记阳性,Bcl-xL蛋白表达明显下降(P<0·05),热诱导细胞凋亡率明显提高(P< 0·05)。结论　硫代反义Bcl-xL寡脱氧核苷酸能诱导BcaCD885颊癌细胞凋亡并能提高其热敏感性。     

转染Bax基因提高BcaCD885颊癌细胞热敏感性的研究

目的：探讨Bax基因对BcaCD885颊癌细胞热敏感性的影响。方法：采用脂质体Lipofectamine 2000转染人Bax-α基因重组质粒pORF-hBax-α于人颊癌细胞株BcaCD885细胞中，再对细胞进行43℃ 40min水浴加温处理，用流式细胞仪检测BcaCD885细胞的凋亡率及Bax蛋白的表达水平；用RT-PCR技术检测BcaCD885细胞的Bax mRNA的表达水平。结果：Lipofectamine 2000能将人Bax-α基因重组质粒pORF-hBax-α导人BcaCD885颊癌细胞中，Bax-α基因重组质粒pORF-hBax-α能在BcaCD885颊癌细胞中表达，提高BcaCD885颊癌细胞内Bax蛋白质及mRNA的水平，促进热诱导BcaCD885颊癌细胞凋亡的发生。结论：转染Bax基因于BcaCD885颊癌细胞内，能提高细胞对热杀伤的敏感性。     

高温诱导颊癌细胞凋亡的相关机理研究

目的：探讨热诱导BcaCD885细胞凋亡的分子机理。方法：水浴加温诱导BcaCD88产生调亡。通过FCM－DNA、FCM－抗体检测技术,观测热诱导颊癌细胞凋亡过程中bcl-2及bax基因蛋白表达的动态变.:地亡率与bcl-2蛋白表达水平存在负相关关系,与bax蛋白表达存在正相关关系。结论：高温作为一种外来刺激信号通过下调bcl-2基因的表达、上调bax基因的表达、上调bax基因的表达,诱导BcaCD885细胞凋亡的发生。     

反义bcl-2寡脱氧核苷酸对BcaCD885细胞凋亡的影响

目的 探讨反义bel-2寡脱氧核苷酸（oligodeoxynucleotide,ODN）对BcaCD885细胞凋亡的影响。方法 以脂质体 Lepofection为载体,一过性转染20μmol/L反义及正义bel-2 ODN于BcaCD885细胞后,通过细胞形态观察及流式细胞术（FCM）分析,从形态学及细胞学水平对凋亡细胞进行检测。结果 20μmol/L反义bel-2 ODN转染组,细胞出现了凋亡形态学改变,FCM检测凋亡率与对照组间存在显著差异（P<0.05）。而 20μmol/L正义bell-2ODN转染组与对照组相似,在形态学上未见明显的凋亡细胞出现,FCM检测两者凋亡率不存在显著差异（P<0.05）。结论 反义 bel-2 ODN能促进 BcaCD885细胞凋亡。     

反义bcl-2寡脱氧核苷酸对BcaCD885细胞内源性bcl-2表达的阻断作用

目的　探讨与 bcl-2翻译起始部位碱基互补的反义 bcl-2寡脱氧核苷酸 ( oligodeoxynucleotide,ODN)对 Bca-CD885细胞内源性 bcl-2表达的阻断作用。方法　以脂质体 Lepofectin为载体 ,一过性转染 2 0 μmol/L 反义及正义 bcl-2 ODN于 Bca CD885细胞中 ,FCM-抗体观测转染后 2 4h、3 6h、48h细胞内 bcl-2基因蛋白表达变化 ,RT-PCR技术检测转染后 2 4h bcl-2 m RNA的表达变化。结果　转染反义 bcl-2 ODN后 2 4h、3 6h、48h Bca CD885细胞内 bcl-2基因蛋白表达与对照组相比都明显下降 ( P<0 .0 5 ) ,而正义组与对照组无差异 ( P>0 .0 5 ) ;正反义组 bcl-2m RNA与对照组相比无明显变化 ( P>0 .0 5 )。结论　反义 bcl-2 ODN能在蛋白翻译水平特异性抑制颊癌细胞内源性 bcl-2蛋白表达     

热诱导颊癌细胞凋亡与Bcl-xL蛋白表达的关系

目的：探讨热诱导颊BcaCD885细胞凋亡与Bcl-xL蛋白表达变化的关系。方法：43℃40min水浴加温诱导BcaCD885细胞产生死亡。采用流式细胞仪（FCM）及抗体检测技术分别测定细胞凋亡率及Bcl-xL蛋白表达量，观测诱导颊癌细胞凋亡过程中Bcl-xL蛋白表达的动态变化，探讨二者间的关系。结果：凋亡组内Bcl-xL蛋白表达量明显低于对照组（P＜0．05），凋亡率与Bcl-xL蛋白表达水平存在负相关关系（r=-0.89，P＜0．05）。结论：Bcl-xL在热诱导BcaCD885细胞凋亡的调控中起重要作用。     

裸鼠体内人腺样囊性癌细胞凋亡的研究

目的　在人涎腺腺样囊性癌 (salivaryadenoidcysticcarcinoma,SACC)裸鼠移植瘤模型上 ,观察重组人肿瘤坏死因子α(recombinedhumantumornecrosisfactor α ,rhTNF α)诱导凋亡的形态学特征及bax、bcl 2蛋白的表达情况。方法　将 6× 10 10 /L的SACC细胞悬液接种于裸鼠皮下建立动物模型后 ,按rhTNF α 10 0× 10 4IU /kg或 10× 10 4IU /kg瘤体内直接注射给药。采用光镜、电镜、流式细胞术及原位凋亡试剂检测盒观察凋亡的形态学变化 ;采用免疫组织化学观察bax、bcl 2的表达情况。结果　移植瘤细胞凋亡率明显高于对照组 ,差异有显著性 (P <0 .0 1)。凋亡细胞核消失后出现钙盐沉积 ,形成砂粒小体。凋亡细胞对bax、bcl 2蛋白的表达明显上升 (P <0 .0 5 )。结论　砂粒体钙化是TNF α诱导的SACC裸鼠移植瘤细胞凋亡的特征和归宿 ;TNF α诱导的细胞凋亡能够特异性增强bax、bcl 2基因蛋白的表达     

nm23-H1基因对舌癌细胞株化疗敏感性的影响体外实验

目的：通过nm23-H1的转化及导入BcaCD885细胞株，观察nm23-H1对BcaCD885细胞株化疗敏感性的影响。方法：完成细胞培养和基因转染后，MTT法观察nm-23-H1对BcaCD885化疗敏感性影响。结果：转染前BcaCD885细胞株对ADM、5－FU、MTX的化疗敏感性无显著差异。但转染后的BcaCD885细胞株对CDDP明显增敏。结论：nm23-H1可能通过特异笥地影响细胞内的能量交换过程来达到对CDDP化疗增敏的效果。     

nm23-H1基因对BcaCD885细胞侵袭、粘附和运动力影响的研究

目的：通过nm23-H1的转化及导入BcaCD885细胞株，建立稳定、高效、低毒的转染方法，观察nm23-H1对BcaCD885细胞株侵袭转移能力的影响。方法：（1）利用基因转化技术，制备高纯度的nm23-H1真核表达质粒；（2）利用阳离子脂质体介导的转染技术，完成转染方法的建立；（3）利用免疫组化技术，检测转染前后的NDPKA的表达；（4）利用transwell小室和冲刷实验，观察转染前后细胞的侵袭、粘附、趋化运动能力的变化。结果：（1）使用重组的pCMV-N-B 的真核表达载体，将nm23-H1转染口腔癌,细胞并获得稳定表达；（2）发现BcaCD885细胞株nm23-H1基因的转染前后表达水平有明显差异；（3）转染后的BcaCD885细胞侵袭、粘附、趋化运动能力均显著降低。结论：nm23-H1对BcaCD885细胞的侵袭转移能力具有显著抑制作用。     

Recovery of A. actinomycetemcomitans from teeth, tongue, and saliva

The recovery of actinobacillus actinomycetemcomitans simultaneously from subgingival sites around teeth and dorsum of the tongue and/or saliva was examined in 293 subjects at 444 visits; 295 paired samples were available from subgingival sites and tongue, 171 paired samples from subgingival sites and stimulated saliva, and 137 paired samples from subgingival sites and unstimulated saliva. Sixty-one subjects were periodontally healthy (mean age 20.3 years); 55 exhibited localized juvenile periodontitis (mean age 21.8 years); 176 adult periodontitis (mean age 46.7 years); and 1 prepubertal periodontitis (age 10 years). When A. actinomycetemcomitans was recovered from subgingival sites, it was also found in 56.3%, 69.9%, and 35.9% of the paired samples from tongue, and stimulated and unstimulated saliva, respectively. No difference in the detection rate of A. actinomycetemcomitans from tongue or stimulated saliva was seen between the subjects with healthy or diseased periodontium. When A. actinomycetemcomitans was not recovered from subgingival sites, it was cultured in 6.8%, 2.0%, and 1.4% of the paired samples from tongue, and stimulated and unstimulated saliva, respectively. In search for noninvasive, inexpensive, and easily run sampling methods for the recovery of oral A. actinomycetemcomitans samples from stimulated saliva and tongue may prove useful in clinical periodontology.     

Academic dentistry

Since 1988, thirteen dental schools have provided dental undergraduate programmes within the United Kingdom (UK). In 2006, two new dental schools were created supporting dental education in the community. A further new dental school in Scotland will be accepting students in autumn 2008. In the past 25 years, extensive reorganisation of the NHS has resulted in long-term implications for the training of medical and dental academic staff. The number of academic clinicians is below the minimum viable level and external constraints, combined with a lack of suitable applicants, have led to a moratorium on academic recruitment within some Dental Schools. A detailed review of the historical and associated factors which have led to the problems presently besetting academic dentistry are discussed along with the initiatives introduced in the last 10 years to revitalise the speciality. Also, the present and future outlook for academic dentistry in other countries are discussed. Opinion is divided as to the appropriate setting for the training of undergraduate students between those who support community-based dental education and those who believe dental education should remain within research led dental establishments. External factors are moulding an unsatisfactory situation that is proving increasingly unattractive to the potential dental academic and the case for reform is obvious.     

Modulation of clinical expression of plaque-induced gingivitis. II. Identification of "high-responder" and "low-responder" subjects

AIM: The aims of this study were to validate a randomized, split-mouth, localized experimental gingivitis model and to identify subjects with different gingivitis susceptibility. MATERIAL AND METHODS: In each of 96 healthy subjects, one maxillary quadrant was randomly assigned as "test" (experimental gingivitis) and the contralateral quadrant as "control". Plaque index (PlI), gingival index (GI), gingival crevicular fluid volume (GCF), and angulated bleeding score (AngBS) were recorded in both quadrants at days 0, 7, 14, and 21. Cumulative plaque exposure (CPE), i.e. PlI over time, was calculated. Day-21 GCF was standardized according to CPE, and residuals of GCF on CPE were calculated. Two subpopulations were then defined, based on upper and lower quartiles of GCF-residual distribution and were, respectively, identified as "high-responder" (HR; n=24) and "low-responder" (LR; n=24). RESULTS: At test quadrants, all parameters significantly increased throughout the trial, while in control quadrants, PlI, GI, and AngBS remained low. Significant differences were noted between test and control quadrants on days 7, 14, and 21 for all parameters. Significant increases in GI, AngBS, and GCF were observed in test quadrants over the course of the study in both HR and LR groups. Significant differences were noted between HR and LR groups for all gingivitis parameters on day 21 in test quadrants, without any significant differences in PlI or CPE between the groups. CONCLUSIONS: We identified two subpopulations characterized by significant differences in clinical parameters of plaque-induced gingival inflammation, despite similar amounts of plaque deposits and plaque accumulation rates.     

鼠颅面部矿化组织发育中非胶原蛋白的表达

目的：骨涎蛋白和骨桥蛋白是矿化组织基质中的主要非胶原蛋白，本研究旨在对它们在矿化组织发育和形成中的可能作用作一探讨。方法：采用免疫组织化学和分子原位杂交技术对各发育阶段的鼠颅面部矿化组织中的骨涎蛋白和骨桥蛋白进行检测。结果：骨涎蛋白主要在新生骨的成骨细胞和类骨质以及前期牙本质中表达；而骨桥蛋白则可在骨形成和骨改建部位的成骨细胞和类骨质以及前期牙本质中出现。结论：结果表明骨涎蛋白与成骨和羟基磷灰石的形成有关；而骨桥蛋白则在矿化形成的不同阶段发挥多重作用。     

Impaired healing response of periodontal furcation defects following flap debridement surgery in smokers. A controlled clinical trial

OBJECTIVES: The purpose of the present parallel-design, controlled clinical trial was to evaluate the treatment outcome of periodontal furcation defects following flap debridement surgery (FDS) procedure in cigarette smokers compared to non-smokers. MATERIALS AND METHODS: After initial therapy, 31 systemically healthy subjects with moderate to advanced periodontitis, who presented at least one Class I or II molar furcation defect, were selected. Nineteen patients (mean age: 40.3 years, 15 males) were smokers (>or=10 cigarettes/day) and 12 patients (mean age: 44.8 years, 3 males) were non-smokers. Full-mouth plaque score (FMPS) and full-mouth bleeding score (FMBS), probing pocket depth (PPD), vertical clinical attachment level (v-CAL), and horizontal clinical attachment level (h-CAL) were assessed immediately before and 6 months following surgery. RESULTS: Overall, statistically significant v-CAL gain was observed in smokers (1.0 +/- 1.3 mm) and non-smokers (1.3+/-1.1 mm), the difference between groups being statistically significant (p=0.0003). In proximal furcation defects, v-CAL gain amounted to 2.3+/-0.7 mm in non-smokers as compared to 1.0+/-1.1 mm in smokers (p=0.0013). At 6 months postsurgery, non-smokers presented a greater h-CAL gain (1.3+/-1.1 mm) than smokers (0.6+/-1.0 mm), with a statistically significant difference between groups (p=0.0089). This trend was confirmed in both facial/lingual (1.4+/-1.0 versus 0.8+/-0.8 mm) and proximal furcation defects (1.2+/-1.3 versus 0.5+/-1.2 mm). The proportion of Class II furcations showing improvement to postsurgery Class I was 27.6% in smokers and 38.5% in non-smokers. After 6 months, 3.4% of presurgery Class I furcation defects in smokers showed complete closure, as compared to 27.8% in non-smokers. CONCLUSIONS: The results of the present study indicated that (1) FDS produced clinically and statistically significant PPD reduction, v-CAL gain, and h-CAL gain in Class I/II molar furcation defects, and (2) cigarette smokers exhibited a less favorable healing outcome following surgery in terms of both v-CAL and h-CAL gain.     

Centric relation definitions taught in 7 dental schools: Results of faculty and student surveys

PURPOSE: The purpose of this investigation was to assess the level of consensus regarding the definition of centric relation and its clinical use in 7 US dental schools. MATERIALS AND METHODS: The preclinical and clinical faculty in the departments of prosthodontics, operative, and general dentistry (n = 137) at 7 dental schools and a convenience sample of fourth year students (n = 150) at the same schools were invited to complete 2-page surveys regarding the definitions and use of centric relation at their institutions. The faculty and student survey included 6 commonly used centric relation definitions from the 1994 Glossary of Prosthodontic Terms, and provided space for writing in definitions not listed on the form. The participants were asked to identify which definition was used at their school. RESULTS: Return rate was 85% for faculty and 75% for students. Both faculty and students identified a low level of consensus regarding the definition and clinical use of centric relation at their dental school. Numerous definitions are in use at each institution. Extramural practice participation and the number of years since dental school graduation were variables associated with the faculty's choice of definition. The faculty who did not participate in an extramural practice chose older definitions. Dental educators graduating before 1975 selected either the oldest or the most recent centric relation definition, whereas the more recent graduates frequently selected the newer definitions. There were no statistical differences between prosthodontic specialists and nonspecialists in choice of definitions. Three courses identified by the students as having the most influence on their understanding of centric relation were preclinical removable prosthodontics, preclinical occlusion, and clinical removable prosthodontics. CONCLUSION: The results of this survey suggest that the controversy will continue, because to date there is no consensus regarding the definition of centric relation within the 7 dental schools surveyed.     

The relationship between periodontal diseases and diabetes: an overview

Diabetes mellitus, caused by the malfunction of insulin-dependent glucose and lipid metabolism, presents with the classical triad of symptoms: polydypsia, polyuria, and polyphagia which are often accompanied by chronic fatigue and loss of weight. Complications of diabetes mellitus include retinopathy, nephropathy, neuropathy, and cardiovascular disease. Periodontal diseases are infections affecting the periodontium and resulting in the loss of tooth support. The association between diabetes mellitus and periodontitis has long been discussed with conflicting conclusions. Both of these diseases have a relatively high incidence in the general population (diabetes 1% to 6% and periodontitis 14%) as well as a number of common pathways in their pathogenesis (both diseases are polygenic disorders with some degree of immunoregulatory dysfunction). On the one hand, numerous reports indicate a higher incidence of periodontitis in diabetics compared to healthy controls, while other reports fail to show such a relationship. Clarification of this dilemma is occurring as the diagnostic criteria for periodontitis and diabetes mellitus improve, controlled studies with increased sample sizes are carried out, and the studies take into account major confounding variables that impact on the pathogenesis of both diseases. Current studies tend to support a higher incidence and severity of periodontitis in patients with diabetes mellitus. The overview looks at the bidirectional relationship between periodontitis and diabetes. An analysis of the National Health and Nutrition Examination Survey (NHANES) III data set confirms the previously reported significantly higher prevalence of periodontitis in diabetics than in non-diabetics (17.3% versus 9%). The analysis of the data also shows that the prevalence of diabetes in patients with periodontitis is double that seen in the non-periodontitis patients (12.5% versus 6.3%) and that this difference is also statistically significant. The pathogenesis of the 2 diseases is reviewed with an emphasis on common genetic and immune mechanisms. On the basis of the overview, 2 hypotheses for testing the relationship between periodontitis and diabetes are discussed. The first proposes a direct causal or modifying relationship in which the hyperglycemia and hyperlipidemia of diabetes result in metabolic alterations that may then exacerbate bacteria-induced inflammatory periodontitis. The second hypothesis proposes that a fortuitous combination of genes (gene sets) could result in a host who, under the influence of a variety of environmental stressors, could develop either periodontitis or diabetes or both.     

Comparative immunohistochemical identification and relative distribution of immunocompetent cells in sections of frozen or formalin-fixed tissue from human periapical inflammatory lesions

Abstract The presence of immunocompetent cells (B, Th/i and Ts/c cells and macrophages) and the ratios of these cell populations in periapical lesions (radicular granulomas, radicular cysts and apical scars) were demonstrated immunohistochemically using paraffin and cryo-sections. Thirty-four human periapical lesions were examined for the presence of immunocompetent cells by monoclonal antibodies and the biotin-avidine-horse-radish peroxidase method. The T/B cell ratio of radicular cysts was significantly higher than that of both radicular granulomas and apical scars, and the average number of Th/i cells was greater than that of Ts/c cells in the radicular granulomas. However, no significant difference was found between radicular cyst and apical scar. The number of macrophages in radicular granulomas was significantly higher than that of the other lesions. These findings suggested that periapical lesions develop as a result of both humoral and cell-mediated immunological response and indicated that the ratios of immunocompetent cells are different in the different types of periapical lesion.     

Factitious Injury of the Oral Mucosa: A Case Series

Gingival and oral mucosal tissues can be the site of a number of mucocutaneous and ulcerative conditions. Generally, these are not difficult to identify on the basis of clinical characteristics, and diagnosis can be aided by the use of routine histopathological and immunopathological techniques as well as other laboratory investigations. Self-induced or factitious injury (FI) of the oral mucosal tissues may present a confusing clinical picture, and be diagnosed erroneously as a mucocutaneous disorder in spite of the absence of appropriate pathological and immunopathological findings, or a failure to respond to routine treatment. A case series is presented here outlining 4 cases of FI which presented initially as mucocutaneous disease. These cases were investigated to rule out systemic or local causes, in order to establish a diagnosis of FT Treatment of these conditions was facilitated with placebo or sham procedures which were designed primarily to cover the lesions. In most cases, the self injurious behavior could be linked to secondary gain. J Periodontol 1995;66:241–245.     

Use of antimicrobial agents during supportive periodontal therapy

Individual susceptibility to periodontal breakdown involves an interplay of genes, periodontal pathogens and other modulating factors. Anti-infective treatment, which includes oral hygiene measures, mechanical debridement, pharmacologic intervention and surgery, has been shown to be effective in arresting the progression of periodontal disease. Nevertheless, due to the chronic nature of the disease, susceptible individuals who are not maintained in a supervised recall program subsequent to the active treatment phase, show signs of recurrent destruction. Supportive periodontal therapy (SPT) is an integral part of periodontal treatment for patients with history of periodontitis, and is needed to prevent recurrence of disease in susceptible individuals. To prevent re-infection with periodontal pathogens, SPT includes elimination of dental plaque and bacteria from the oral cavity, thereby preventing the recurrence of pathogens into the gingival area. For individuals at risk of developing periodontitis, SPT should combine self-performed and professional anti-infective therapy, using mechanical and pharmacological means. The existing evidence suggests that the adjunctive use of antimicrobial pharmacologic therapy during SPT may enhance the results of mechanical debridement. The use of antimicrobials varies between patients, and is dependent on risk assessment and longitudinal monitoring of the clinical status of the periodontium.