Single-step, self-etch adhesives behave as permeable membranes after polymerization. Part III. Evidence from fluid conductance and artificial caries inhibition

PURPOSE: To test the hypothesis that formation of inhibition zones by bonded restorations in artificially-induced carious dentin lesions is related to the permeability of the self-etch adhesives. METHODS: Fluid conductance of four single-step self-etch adhesives (Prompt L-Pop, Etch&Prime 3.0, One-Up Bond F and Reactmer Bond), and a control two-step self-etch adhesive (UniFil Bond) were measured after sound dentin surfaces were:(1) acid-etched; (2) polished to produce smear layers; (3) bonded with the adhesive; each at 20 cm hydrostatic pressure (hp). Osmotic fluid conductance was also determined for the bonded dentin after immersion in 4.8 M CaCl2 at 0 cm hp. For artificial caries inhibition, a non-fluoride releasing (NFR) two-step self-etch adhesive (UniFil Bond) and a fluoride-releasing (FR) single-step adhesive (Reactmer Bond) were used in combination with a NFR composite (Metafil CX) or a FR restorative material (Reactmer Paste). Artificial caries were induced in these restorations, from which 120 +/- 10 microm thick sections and the effect of caries inhibition were quantitatively assessed with polarizing light microscopy and image analysis. RESULTS: Fluid conductance after bonding with the single-step adhesives Prompt L-Pop and Etch&Prime 3.0 were not significantly different from those recorded from smear layer-covered dentin. Although better seals were achieved with One-Up Bond F and Reactmer Bond, fluid conductance at 20 cm hp was significantly higher than the two-step self-etch adhesive UniFil Bond. Osmotic conductance at 0 cm hp were not significantly different from normal fluid conductance at 20 cm hp. The sizes of artificial carious lesions in UniFil Bond were significantly higher irrespective of whether a FR or NFR composite was used. Significant reduction in lesion size occurred in Reactmer Bond with the use of a NFR composite, and even more so with the use of a FR composite.     

Creating an effective PBL case in oral and maxillofacial surgery at a Chinese dental school: a dental education primer

Problem-based learning (PBL) is a widely accepted educational method centered on the discussion and learning that emerge from a clinically based problem; however, little has been reported on the details of PBL case-writing in the dental education literature. This article outlines some principles of writing a PBL case as it is practiced at a Chinese dental school and presents, as an example, an actual case based on a clinical problem (ameloblastoma of the jaw) intended to provide a learning focus for predoctoral dental students. A good PBL case should allow for progressive, interdependent actions to be taken in the evaluation and overall management of the patient in context and should trigger inquiry and discussion among students in both the basic sciences (anatomy, physiology, biochemistry, pharmacology, pathophysiology, etc.) and related clinical sciences. The epidemiological, sociological, and ethical considerations related to each problem should also be emphasized as an essential component of effective health care provision.     

多曲方丝弓矫治技术在直丝弓矫治器中的应用

目的：观察MEAW技术在直丝弓矫治器中矫治错[牙合]的临床效果,探讨其矫治特点。方法：选择0.022″系统的直丝弓矫治器,使用MEAW技术对10例Ⅲ类错[牙合]和3例前牙开[牙合]病例进行矫治。结果：13例患者均取得了满意的临床矫治效果。结论：在直丝弓矫治器中使用MEAW技术矫治错[牙合]效果明显,值得临床推广。     

应力对纯钛表面成骨细胞核结合因子α1形成和表达的影响

目的观察应力对纯钛表面成骨细胞核结合因子α1（Cbfα1）形成及表达的影响，揭示应力对支抗种植体周骨反应的调控机制。方法用大小为2.205 N的间断离心力刺激接种于纯钛表面的成骨细胞，刺激频率为每培养4 h加力15 min，分别于4、8、12 h后收集细胞，采用免疫荧光法检测Cbfα1的形成，提取总RNA并应用逆转录聚合酶链反应检测Cbfα1 mRNA的表达。结果纯钛表面加力组和不加力组MG-63成骨细胞的细胞核内均有Cbfα1荧光染色，且加力组Cbfα1蛋白荧光强度较不加力组多，差异有统计学意义（P＜0.05）；纯钛表面加力组和不加力组MG-63成骨细胞Cbfα1 mRNA表达均为阳性，且加力组Cbfα1 mRNA表达较不加力组多，差异有统计学意义（P＜0.05）。结论成骨细胞受力后Cbfα1基因形成和表达增强，提示间歇性的牵引应力可以促进纯钛表面成骨细胞的活性。     

Establishment of cell free conversion system with biotin-labelled recombinant PrPsen expressed in E. coli

Objective To report a protocol using biotin-labelled PrP protein in cell free conversion assay instead of isotope. Methods A hamster PrP protein （HaPrP） was expressed in E. coli and purified with HIS-tag affinity chromatograph. After being labelled with biotin, HaPrP was mixed with PrP^sen preparation from scrapie strain 263K. Results Protease-resistant bands were detected after four-day incubation. Conclusion The new conversion model provides a reliable, easily handling, and environment-friendly method for studies of prion and transmissible spongiform encephalopathies.     

血小板分布宽度计数比值与脓毒症心肌病休克的相关性

目的探讨血小板分布宽度计数比值(PDW/PC)与脓毒症心肌病休克的相关性。方法回顾性分析100例脓毒症心肌病患者的临床资料。观察休克组与非休克组的血小板分布宽度(PDW)、血小板计数(PC)等指标。相关性采用Spearman分析,诊断准确率应用受试者工作特征曲线(ROC)曲线。结果休克组PC显著低于非休克组,PDW/PC显著高于非休克组。PDW与急性生理与慢性健康(APACHEⅡ)评分呈正相关(r＝0.404,P＜0.01),PC与APACHEⅡ评分呈负相关(r＝－0.739,P＜0.01)。PDW/PC诊断脓毒症心肌病休克的曲线下面积AUC=0.910(P＜0.01)。结论PDW/PC与脓毒症心肌病休克病情严重程度相关,对其具有一定的诊断价值。     

新型冠状病毒肺炎防控期间居家隔离人群心理健康状况调查及影响因素分析

目的 了解新型冠状病毒肺炎防控期间居家隔离人群心理健康状况并分析其影响因素,为进一步做好疫情防控工作,疏导不良情绪及心理恐慌提供依据.方法 选取2020年2月15 17日本研究团队7名研究生居住地为调查单位,采用自制一般情况调查表及12项一般健康问卷(GHQ-12)量表调查居家隔离的380人的心理健康状况.根据GHQ-12评分,将调查对象分为GHQ-12≥3分为阳性组(n=212)和GHQ-12＜3分为阴性组(n=168).采用Logistic回归模型分析居家隔离人群心理健康状况的影响因素.结果 两组在年龄、性别、是否独生子女、经济收入方面比较,差异无统计学意义(P＞0.05);而在居住地、婚姻状况、生育情况、担心感染、文化程度、职业方面差异有统计学意义(P＜0.05).多因素Logistic回归分析结果显示,居住地农村、初中及以下文化程度、已婚、学生、外出务工人员、担心感染是居家隔离人群心理健康的危险因素,年龄是其保护因素.结论 新型冠状病毒肺炎防控期间,居家隔离人群存在一定心理健康问题,其受多种因素影响.医院或社区卫生中心应针对不同人群进行心理疏导,改善其身心健康.     

Inverted U-Shaped Associations between Glycemic Indices and Serum Uric Acid Levels in the General Chinese Population: Findings from the China Cardiometabolic Disease and Cancer Cohort (4C) Study

Objective The relationship between serum uric acid(SUA)levels and glycemic indices,including plasma glucose(FPG),2-hour postload glucose(2 h-PG),and glycated hemoglobin(HbA1 c),remains inconclusive.We aimed to explore the associations between glycemic indices and SUA levels in the general Chinese population.Methods The current study was a cross-sectional analysis using the first follow-up survey data from The China Cardiometabolic Disease and Cancer Cohort Study.A total of 105,922 community-dwelling adults aged≥40 years underwent the oral glucose tolerance test and uric acid assessment.The nonlinear relationships between glycemic indices and SUA levels were explored using generalized additive models.Results A total of 30,941 men and 62,361 women were eligible for the current analysis.Generalized additive models verified the inverted U-shaped association between glycemic indices and SUA levels,but with different inflection points in men and women.The thresholds for FPG,2 h-PG,and HbA1 c for men and women were 6.5/8.0 mmol/L,11.0/14.0 mmol/L,and 6.1/6.5,respectively(SUA levels increased with increasing glycemic indices before the inflection points and then eventually decreased with further increases in the glycemic indices).Conclusion An inverted U-shaped association was observed between major glycemic indices and uric acid levels in both sexes,while the inflection points were reached earlier in men than in women.     

国际学院外科实习教学研究探讨

探讨首都医科大学国际学院学生临床外科教学存在的问题及教学模式.留学生存在跨文化适应障碍,文化背景和宗教信仰有所不同且思维活跃.现阶段对临床留学生的教育普遍存在缺乏有经验的教师、缺乏因地制宜的教材、缺乏行之有效的教学法.通过对临床带教模式的改革,对国际学院学生进行外科分组轮转,1对1带教,加强操作,鼓励动手实践.对临床教师进行定期培训和考核,加强临床操作教学,放手不放眼,教授临床知识,引导学生对临床专科职业方向的选择.为了确保和提高国际学院学生的教学质量,加强临床一线医师和国际学院学生的共同参与性,对留学生外科临床实习教学内容、教学方式、教学方法 、教学模式等方面进行探索、建设和改革.