Adjunctive Application of Antimicrobial Photodynamic Therapy in Nonsurgical Periodontal Treatment: A Review of Literature

Periodontal disease is caused by dental plaque biofilms, and the removal of these biofilms from the root surface of teeth plays a central part in its treatment. The conventional treatment for periodontal disease fails to remove periodontal infection in a subset of cases, such as those with complicated root morphology. Adjunctive antimicrobial photodynamic therapy (aPDT) has been proposed as an additional treatment for this infectious disease. Many periodontal pathogenic bacteria are susceptible to low-power lasers in the presence of dyes, such as methylene blue, toluidine blue O, malachite green, and indocyanine green. aPDT uses these light-activated photosensitizer that is incorporated selectively by bacteria and absorbs a low-power laser/light with an appropriate wavelength to induce singlet oxygen and free radicals, which are toxic to bacteria. While this technique has been evaluated by many clinical studies, some systematic reviews and meta-analyses have reported controversial results about the benefits of aPDT for periodontal treatment. In the light of these previous reports, the aim of this review is to provide comprehensive information about aPDT and help extend knowledge of advanced laser therapy.     

Precursor system of liquid crystalline phase containing propolis microparticles for the treatment of periodontal disease: development and characterization

Precursor systems of liquid crystalline phase were prepared using the surfactant PPG-5-Ceteth-20, isopropyl myristate, and water; gelatin microparticles containing propolis were then added into these systems. Homogeneity of dispersion, the in-system microparticle morphology, and sedimentation behavior of each formulation were evaluated. The rheological and mechanical properties (hardness, compressibility, and adhesiveness), the work of syringing, and the propolis release profile were also evaluated. All the formulations exhibited pseudoplastic flow and thixotropy, and they displayed storage modulus, loss modulus, dynamic viscosity, and loss tangent that depended on temperature, frequency, and composition. Mechanical properties varied significantly among the formulations being affected by changes in the composition and temperature. Raising the concentration of surfactant and adding propolis microparticles significantly decreased the work of syringing. The drug release was non-Fickian (anomalous) and there was no significant difference between the tested systems in the times required for 10%, 30%, and 50% release of the initial drug loading.     

Analytical Prediction of Crack Coalesce in Multiple Site Damaged Structures

An analytical methodology for predicting the condition when interacting cracks coalesce and estimate the residual strength under Multiple Site Damage situations is proposed. Dominating magnitudes of the criterion are the changes in elastic and plastic strain energy due to crack ligament fracture. The strain energy magnitudes of interest are calculated using analytical formulations, such that the methodology is efficiently applicable in the design of real aircraft panels. Link-up stress predictions using the present methodology are in very good correlation to the experiments and in most cases better, as compared to the alternative crack link-up prediction models.     

Enhanced phagocytosis of Aggregatibacter actinomycetemcomitans cells by macrophages activated by a probiotic Lactobacillus strain

The activation of phagocytosis is one important approach to clearing pathogenic cells in a host. This study evaluated the ability of probiotic lactobacilli to induce phagocytic activity as well as the clearance of a periodontal pathogen, Aggregatibacter actinomycetemcomitans. First, the activation of phagocytosis was found by using lyophilized dead cells. Probiotic Lactobacillus strains significantly enhanced the phagocytic activity of macrophage cells, indicating that the probiotic lactobacilli have a remarkable ability to stimulate the macrophages. Essentially, 3 Lactobacillus strains tested did not have any critical toxic effect on the murine macrophage, and Lactobacillus johnsonii NBRC 13952 showed the least cytotoxic effect on the RAW264.7 macrophages. The expression of classically activated macrophage markers, IL-1β, and cluster of differentiation 80 increased by L. johnsonii NBRC 13952; however, there was no significant difference for IL-18. The highest phagocytic activity by macrophages was found in a condition in which the macrophage activated by L. johnsonii NBRC 13952 functions to kill the cells of A. actinomycetemcomitans. Correlating with the result, a high amount of hypodiploid DNA (SubG1) was detected from the macrophage cells stimulated by L. johnsonii NBRC 13952. Taken together, the results suggest that macrophages activated by the Lactobacillus strain can facilitate the phagocytosis of A. actinomycetemcomitans cells by linking with enhanced apoptotic activities. In conclusion, L. johnsonii NBRC 13952 has a certain role in activating the RAW264.7 macrophages, thereby counteracting the infection of A. actinomycetemcomitans.     

ASME法规中筒体壁厚计算不同方法的合理选用

在对ASME法规开孔筒体强度计算中的减弱系数法和开孔补强法进行对比分析的基础上,得出了当筒体开孔节距小于或等于补强有效范围时,采用开孔补强法求得了筒体壁厚较小;当前者大于后者时,采用减弱系数法求得了筒体壁厚较小的结论。指出根据筒体结构的不同特点,合理选用法规中的相应计算方法,可以使设计的产品既保证安全又节省材料。还给出了作为上述结论论据的例题。     

Human Periodontal Ligament Stem Cell and Umbilical Vein Endothelial Cell Co-Culture to Prevascularize Scaffolds for Angiogenic and Osteogenic Tissue Engineering

(1) Background: Vascularization remains a critical challenge in bone tissue engineering. The objective of this study was to prevascularize calcium phosphate cement (CPC) scaffold by co-culturing human periodontal ligament stem cells (hPDLSCs) and human umbilical vein endothelial cells (hUVECs) for the first time; (2) Methods: hPDLSCs and/or hUVECs were seeded on CPC scaffolds. Three groups were tested: (i) hUVEC group (hUVECs on CPC); (ii) hPDLSC group (hPDLSCs on CPC); (iii) co-culture group (hPDLSCs + hUVECs on CPC). Osteogenic differentiation, bone mineral synthesis, and microcapillary-like structures were evaluated; (3) Results: Angiogenic gene expressions of co-culture group were 6–9 fold those of monoculture. vWF expression of co-culture group was 3 times lower than hUVEC-monoculture group. Osteogenic expressions of co-culture group were 2–3 folds those of the hPDLSC-monoculture group. ALP activity and bone mineral synthesis of co-culture were much higher than hPDLSC-monoculture group. Co-culture group formed capillary-like structures at 14–21 days. Vessel length and junction numbers increased with time; (4) Conclusions: The hUVECs + hPDLSCs co-culture on CPC scaffold achieved excellent osteogenic and angiogenic capability in vitro for the first time, generating prevascularized networks. The hPDLSCs + hUVECs co-culture had much better osteogenesis and angiogenesis than monoculture. CPC scaffolds prevacularized via hPDLSCs + hUVECs are promising for dental, craniofacial, and orthopedic applications.     

抗肿瘤坏死因子单抗对脂多糖诱导的人牙周膜成纤维细胞TRAIL和TNF-α的影响

目的: 观察脂多糖对人牙周膜成纤维细胞(HPLFs )肿瘤坏死因子(TNF)受体相关凋亡诱导配体(TRAIL) 和TNF-α的诱导作用及抗肿瘤坏死因子单抗(抗TNF单抗)对其的影响,探讨TNF超家族参与牙周病的可能作用机制。方法: HPLFs培养至第6代, 加入不同浓度的脂多糖(0、0.1、1、10、100 μg/mL)培养 24 h,分为命名为Z₀组、Z_0.1组、Z₁组、Z₁₀组、Z₁₀₀组,并取Z₁组浓度的脂多糖,在加药的同时加抗TNF单抗 75 μg/mL( Z₁+75组)。分别采用实时荧光定量PCR法或Western blot法测定TRAIL 和TNF-α mRNA或蛋白的表达。结果: Z₁组、Z₁₀组HPLFs TRAIL mRNA的表达水平显著高于Z₀组或Z_0.1 组(均P<0.05),Z₁组与Z₁₀组之间差异无统计学意义(P>0.05); Z₁₀₀组显著高于Z₀组(P<0.05)且与Z_0.1组、Z₁组和Z₁₀组比较差异无统计学意义(均P>0.05)。Z₁组或Z₁₀组TNF-α mRNA的表达水平显著高于Z₀组或Z₁₀₀组(均P<0.05);Z₁组与Z₁₀组之间,Z₀组、Z_0.1组和Z₁₀₀组之间差异无统计学意义(均P>0.05)。HPLFs TRAIL 蛋白的表达水平在Z₁₀₀组0组0.1组1组(均P<0.05 或<0.01);Z₁₀组显著高于Z₀组或Z₁₀₀组(均P<0.01),但与Z_0.1组或Z₁组之间差异无统计学意义(均P>0.05)。抗TNF单抗治疗后TRAIL mRNA及蛋白和TNF-α mRNA的表达水平显著低于Z₁组(P<0.05 和P<0.01)。TRAIL和TNF-α mRNA的表达水平呈显著直线正相关(r=0.819,n=30, P<0.01)。结论: HPLFs经脂多糖诱导后,其TRAIL和TNF-α的表达呈现先升高后下降,且随脂多糖的浓度变化而相应地变化,这种诱导作用能被抗TNF单抗所抑制。     

硫酸镁联合罗哌卡因股神经阻滞对膝关节韧带修复术患者下肢止血带反应的疗效观察

目的:探讨硫酸镁联合罗哌卡因股神经阻滞对膝关节韧带修复术下肢止血带反应的疗效。方法:选择2016年2月至2018年2月于本院拟行关节镜下膝关节韧带修复术的患者83例作为本研究对象,随机分为试验组（n=42）和对照组（n=41）;两组均在超声引导下实施患侧股神经阻滞麻醉,试验组给予0.375%罗哌卡因15 mL（含有0.75 g硫酸镁）混合液注射,对照组给予0.375%罗哌卡因15 mL注射,两组麻醉成功后均于大腿中上1/3处缚扎自动充气止血带。比较两组感觉和运动阻滞起效时间、持续时间和镇痛时间、不同时间点血流动力学和血清丙二醛（MDA）、肿瘤坏死因子-α（TNF-α）的变化,记录止血带反应发生率和药物不良反应。结果:与对照组相比,试验组感觉阻滞和运动阻滞起效时间缩短,持续时间、镇痛时间延长（P<0.05）;两组不同时间点收缩压（SBP）、舒张压（DBP）、心率（HR）比较,差异均具有统计学意义（P<0.05）;试验组T7、T8血清MDA、TNF-α高于对照组（P<0.05）;两组止血带反应发生率分别为7.14%（3/42）和24.39%（10/41）,差异具有统计学意义（P<0.05）;两组不良反应发生率差异无统计学意义（P>0.05）。结论:在膝关节韧带修复术中应用硫酸镁混合罗哌卡因股神经阻滞效果显著,可有效维持血流动力学稳定、延长阻滞效果,缓解氧化应激和炎症反应,减少止血带反应,安全性高,值得应用推广。     

谈斜支撑在成都东郊基坑支护工程中的运用

通过工程实例,介绍了斜支撑支护体系在成都东郊膨胀性粘土地区基坑支护中的运用,指出由于斜支撑刚度大,可靠度高,可大大减少原支护结构中支护桩的嵌固深度,经济性好,可作为该区域较可靠的一种基坑支护方式。     

In Vivo Characteristics of Premixed Calcium Phosphate Cements When Implanted in Subcutaneous Tissues and Periodontal Bone Defects

Previous studies showed that water-free, premixed calcium phosphate cements (Pre-CPCs) exhibited longer hardening times and lower strengths than conventional CPCs, but were stable in the package. The materials hardened only after being delivered to a wet environment and formed hydroxyapatite as the only product. Pre-CPCs also demonstrated good washout resistance and excellent biocompatibility when implanted in subcutaneous tissues in rats. The present study evaluated characteristics of Pre-CPCs when implanted in subcutaneous tissues (Study I) and used for repairing surgically created two-wall periodontal defects (Study II). Pre-CPC pastes were prepared by combining CPC powders that consisted of CPC-1: Ca(4)(PO(4))(2)O and CaHPO(4), CPC-2: α-Ca(3)(PO(4))(2) and CaCO(3) or CPC-3: DCPA and Ca(OH)(2) with a glycerol at powder-to-liquid mass ratios of 3.5, 2.5, and 2.5, respectively. In each cement mixture, the Ca to P molar ratio was 1.67. The glycerol contained Na(2)HPO(4) (30 mass %) and hydroxypropyl methylcellulose (0.55 %) to accelerate cement hardening and improve washout resistance, respectively. In Study I, the test materials were implanted subcutaneously in rats. Four weeks after the operation, the animals were sacrificed and histopathological observations were performed. The results showed that all of the implanted materials exhibited very slight or negligible inflammatory reactions in tissues contacted with the implants. In Study II, the mandibular premolar teeth of mature beagle dogs were extracted. One month later, two-wall periodontal bone defects were surgically created adjacent to the teeth of the mandibular bone. The defects were filled with the Pre-CPC pastes and the flaps replaced in the preoperative position. The dogs were sacrificed at 1, 3 and 6 months after surgery and sections of filled defects resected. Results showed that one month after surgery, the implanted Pre-CPC-1 paste was partially replaced by bone and was converted to bone at 6 months. The pockets filled with Pre-CPC-2 were completely covered by newly formed bone in 1 month. The Pre-CPC-2 was partially replaced by trabecular bone in 1 month and was completely replaced by bone in 6 months. Examination of 1 month and 3 month samples indicated that Pre-CPC-2 resorbed and was replaced by bone more rapidly than Pre-CPC 1. Both Pre-CPC pastes were highly osteoconductive. When implanted in periodontal defects, Pre-CPC-2 was replaced by bone more rapidly than Pre-CPC-1.