人工肌肉及其在直接心脏辅助装置中的应用前景

人工心脏是目前解决心脏移植供心来源不足的一种有效途径.而新型的、有效的致动器的研究开发及应用,在人工心脏技术发展中处于至关重要的地位.本文介绍了近年新发展的致动器:人工肌肉,阐述了它的分类和原理,并将其在直接心脏辅助装置应用中所必需的几种特性参数进行了分析比较,对它在目前所存在的问题和前景作了探讨.     

丝胶对Ⅱ型糖尿病大鼠海马生长激素/胰岛素样生长因子-1轴的作用

目的:探讨丝胶对Ⅱ型糖尿病大鼠海马生长激素(GH)/胰岛素样生长因子-1(IGF-1)轴的作用.方法:雄性SD大鼠随机分为正常对照组、糖尿病模型组、丝胶治疗组和阳性对照组.2％链脲佐菌素3d连续腹腔注射的方法建立Ⅱ型糖尿病大鼠模型后,丝胶治疗组和阳性对照组大鼠分别给予丝胶和二甲双胍灌胃治疗35 d.ELISA法检测各组大鼠血清GH和IGF-1水平,免疫印迹和RT-PCR法分别检测大鼠海马GH、生长激素受体(GHR)和IGF-1蛋白和mRNA的表达.结果:与正常对照组大鼠比较,糖尿病模型大鼠血清GH水平、海马GH的表达明显升高,血清IGF-1水平、海马GHR和IGF-1的表达明显降低;与糖尿病模型组大鼠比较,丝胶治疗组大鼠血清GH水平、海马GH的表达明显降低,血清IGF-1水平、海马GHR和IGF-1的表达明显升高.结论:丝胶可通过调节糖尿病海马GH/IGF-1轴的异常变化减轻海马损伤.     

Recovery of Oral In Vitro Biofilms after Exposure to Peptides and Chlorhexidine

IntroductionThis study aimed to examine the dynamic recovery of established multispecies biofilms of oral bacteria after an initial treatment by D-enantiomeric peptide DJK-5, L-enantiomeric peptide 1018, or chlorhexidine digluconate (CHX).MethodsOral biofilms from 2 donors were grown on collagen-coated hydroxyapatite disks for 3 weeks and exposed to DJK-5, 1018, and 2% CHX for 3 minutes. Immediately after treatment and 1, 2, 3, 5, 7, 8, and 12 weeks after exposure, the biofilm volume and the volume ratio of dead and live bacteria in biofilms were assessed by confocal laser scanning microscopy using a live/dead viability stain. Results were examined by 1-way analysis of variance and post hoc multiple comparisons to determine significance at a P < .05 significance level.ResultsDJK-5 killed almost 80% of biofilms in 3 minutes and maintained this high level of dead bacteria for 1 week. The proportion of viable bacteria in DJK-5–treated biofilms returned to the pretreatment level after 12 weeks. The biovolume of DJK-5–treated biofilm remained significantly lower than that of biofilms after CHX and no treatment throughout the 12-week follow-up period (P < .001). The proportion of dead bacteria was higher in biofilms exposed to DJK-5 than with 1018 or CHX for 8 weeks after the exposure (P < .001). The proportion of dead bacteria almost doubled to 46%–52% during the first 7 days after the 3-minute exposure to CHX and peptide 1018. The timeline of biofilm recovery was slow but similar after exposure to CHX and the 2 peptides.Conclusionsecovery time after exposure to DJK-5 was longer than that after exposure to 1018 and CHX. Peptide 1018 showed a delayed, continued antibacterial effect similar to that of 2% CHX against the biofilm microbes.     

漂白剂对复合树脂的影响

临床上常需要对存在复合树脂修复体的牙进行漂白,或者对漂白后的牙进行复合树脂修复。由于漂白剂具有较强的氧化性及反应活性,在一定程度上影响了复合树脂的性能如微硬度、表面粗糙度等;因此,研究漂白剂对复合树脂的影响有重要的临床意义。本文就漂白剂对复合树脂表面性能、与釉质和牙本质粘接强度、微渗漏、颜色等的影响作一综述。     

Bioceramic materials in endodontics

During the past two decades, a number of major advances have been made in the field of bioactive ceramics used for endodontic treatment. This article reviews the physico-chemical and biological properties of bioceramic materials and the application of bioceramic technology to endodontics. Bioceramic materials, with their biocompatible nature and excellent physico-chemical properties, are widely used in endodontic applications. They can function as cements, root repair materials, root canal sealers and filling materials, which have the advantages of enhanced biocompatibility, potential increased root strength following obturation, antibacterial properties and sealing ability. New bioceramic materials have demonstrated the ability to overcome some of the significant limitations of earlier generations of endodontic materials. Most bioceramic materials have been shown to be biocompatible and have good physico-chemical characteristics, therefore having a potential use in clinical endodontics. Although in vitro studies on the use of bioceramic materials in endodontics have given encouraging results, randomized and double-blind clinical studies of sufficient length with these materials are needed to confirm long-term success following their use.     

Dental materials with antibiofilm properties

Objectives

Oral bacteria have evolved to form biofilms on hard tooth surfaces and dental materials. The antibiofilm effect of materials used for the restoration of oral function affects oral health. In this review we describe the features involved in the formation of oral biofilms on different surfaces in the oral cavity and the antibiofilm properties of dental materials.

Methods

An electronic search of scientific papers from 1987 to 2013 was performed with PubMed, ScienceDirect and Google search engines using the following search terms: antibiofilm, dental material, dental hard tissue, endodontic material, implant material, oral biofilm, and restorative material.

Results

Selected inclusion criteria resulted in 179 citations from the scientific, peer-reviewed literature. Oral biofilms form not only on dental hard tissue, but also on a wide range of dental materials used in cariology, endodontics, restorative dentistry and periodontology, resulting in destruction of dental hard tissue and even infection. Therefore, there has been a continuous effort to develop the antibiofilm properties of dental materials used for different purposes. Specific antimicrobial design in the composition and application of new materials (e.g. bioceramic sealer, resin composite, implant coating) demonstrates an improvement of the antibiofilm properties of these materials compared to earlier generations.

Significance

A significant number of dental materials have been shown to affect biofilm growth by inhibiting the adhesion of bacteria, limiting their growth or killing microbes in the biofilms formed in vitro. Incorporation of an appropriate amount of antibacterial agent could provide dental materials with antibiofilm activity without significantly influencing their mechanical properties. However, more randomized and double-blind clinical studies of sufficient length with these materials are needed to confirm long term success following their use in the dental clinic.     

川芎嗪配合三联疗法治疗老年人消化性溃疡

目的 观察川芎嗪配合奥美拉唑三联疗法治疗老年人消化性溃疡的临床疗效.方法 23例幽门螺杆菌(Hp)阳性的消化性溃疡患者(治疗组)给予川芎嗪合奥美拉唑三联疗法,对照组23例仅给予奥美拉唑三联疗法,疗程4周;观察两组治疗后临床症状改善和溃疡愈合情况、Hp根除率,及随访复发率.结果 治疗组临床症状改善和溃疡愈合情况及Hp根除率明显高于对照组(P＜0.05).治疗组复发率低于对照组(P＜0.05).结论 川芎嗪协同奥美拉唑三联疗法是治疗Hp相关性消化性溃疡的有效方法.     

Biocompatibility of a New Calcium Silicate-Based Root Canal Sealer Mediated via the Modulation of Macrophage Polarization in a Rat Model

(1) Background: The EndoSequence BC Sealer HiFlow (Brasseler, Savannah, GA, USA) has recently been introduced in clinical applications. Thus, the aims of the present study are to determine its biocompatibility in vivo and to examine its ability to drive macrophage polarization in vitro and in vivo. (2) Methods: HiFlow was implanted into rat connective tissue for 7, 30 and 150 days. The microstructures and elemental compositions were determined by scanning electron microscopy-energy-dispersive X-ray spectroscopy (SEM-EDX). Hematoxylin–eosin, immunofluorescence, RT–qPCR and flow cytometry were used to elucidate the effects on inflammatory responses and macrophage polarization. (3) Results: SEM-EDX revealed the formation of surface hydroxyapatite crystal layers. Histological evaluation showed that HiFlow exhibited long-term biocompatibility because it decreased inflammatory responses and reduced the number of macrophages over time; however, tissue necrosis was observed in all the groups. RT–qPCR verified that HiFlow regulated the expression of inflammatory factors to inhibit the inflammatory response. Immunofluorescence analysis performed on in vivo samples revealed that HiFlow promoted M2-like macrophage polarization, and these results were confirmed by flow cytometry in vitro. (4) Conclusion: After 150 days of investigation, HiFlow was considered biologically acceptable, and the formation of apatite crystal layers and the promotion of M2-like macrophage polarization may contribute to its favorable biocompatibility.     

Effect of desensitising toothpastes on dentinal tubule occlusion: A dentine permeability measurement and SEM in vitro study

Objectives

The purpose of this study was to evaluate the in vitro effectiveness of a new bioglass-containing and two commercial desensitising toothpastes on dentinal tubule occlusion after citric acid challenge or artificial saliva (AS) immersion.

Methods

One hundred dentin discs from human third molars were used. Specimens were randomly divided into five groups (n = 20), Group 1: EDTA-treated dentin; Group 2: brushing with distilled water; Group 3: brushing with Novamin; Group 4: brushing with Sensodyne Freshmint; Group 5: brushing with Colgate Sensitive. In each group, samples were then equally split into two subgroups (n = 10) to test two post-treatments: 6% citric acid challenge or 24 h immersion in artificial saliva. Dentine permeability of each specimen was measured before and after each treatment using a hydrostatic device working at 20 cm H₂O pressure. Data were analysed by two-way repeated measures ANOVA to determine if there were any significant differences within or between groups. Dentine morphology and surface deposits were observed by SEM.

Results

All three desensitising toothpastes significantly reduced dentine permeability and created precipitates on the treated dentine surfaces. Moreover, the reductions in dentine permeability showed partial recovery after a citric acid and artificial saliva immersion. Sensodyne showed significant resistant to acid attack and Novamin exhibited the lowest permeability after artificial saliva immersion for 24 h.

Conclusions

The application of the three toothpastes resulted in effective dentinal tubule occlusion. However, the new bioglass-containing toothpaste (Novamin) represented excellent occlusion effects after brushing treatment and AS immersion, while Sensodyne demonstrated more reduction in permeability when citric acid challenged.