Heparin microparticle effects on presentation and bioactivity of bone morphogenetic protein-2

Biomaterials capable of providing localized and sustained presentation of bioactive proteins are critical for effective therapeutic growth factor delivery. However, current biomaterial delivery vehicles commonly suffer from limitations that can result in low retention of growth factors at the site of interest or adversely affect growth factor bioactivity. Heparin, a highly sulfated glycosaminoglycan, is an attractive growth factor delivery vehicle due to its ability to reversibly bind positively charged proteins, provide sustained delivery, and maintain protein bioactivity. This study describes the fabrication and characterization of heparin methacrylamide (HMAm) microparticles for recombinant growth factor delivery. HMAm microparticles were shown to efficiently bind several heparin-binding growth factors (e.g. bone morphogenetic protein-2 (BMP-2), vascular endothelial growth factor (VEGF), and basic fibroblast growth factor (FGF-2)), including a wide range of BMP-2 concentrations that exceeds the maximum binding capacity of other common growth factor delivery vehicles, such as gelatin. BMP-2 bioactivity was assessed on the basis of alkaline phosphatase (ALP) activity induced in skeletal myoblasts (C2C12). Microparticles loaded with BMP-2 stimulated comparable C2C12 ALP activity to soluble BMP-2 treatment, indicating that BMP-2-loaded microparticles retain bioactivity and potently elicit a functional cell response. In summary, our results suggest that heparin microparticles stably retain large amounts of bioactive BMP-2 for prolonged periods of time, and that presentation of BMP-2 via heparin microparticles can elicit cell responses comparable to soluble BMP-2 treatment. Consequently, heparin microparticles present an effective method of delivering and spatially retaining growth factors that could be used in a variety of systems to enable directed induction of cell fates and tissue regeneration.     

Similar Influence of Stabilized Alkaline and Neutral Sodium Hypochlorite Solutions on the Fracture Resistance of Root Canal–treated Bovine Teeth

Introduction

Stabilizing sodium hypochlorite (NaOCl) at an alkaline pH is proposed to increase solution stability and tissue dissolution ability; however, a reduction on the flexural strength of dentin discs has been found to be a side effect. This study sought to determine whether a stabilized alkaline NaOCl reduces the fracture resistance of root canal–treated bovine teeth after root canal preparation compared with a neutral solution counterpart.

Methods

The 4 anterior incisors were removed from 20 mandibular bovine jaws, and each 1 was randomly assigned to 1 of 4 groups (20 teeth each). Teeth were prepared with a sequence of 6 K-type files. The following experimental groups received a different irrigation regimen: G1: distilled water (negative control), G2: 5% NaOCl at a pH of 7.2, and G3: 5% NaOCl at a pH of 12.8; in the positive control group (G4), teeth remained untreated. The time of contact and volume of solution were carefully standardized. After bone and periodontal ligament simulation, teeth were subjected to a fracture resistance test.

Results

A significant difference was observed among the 4 groups tested (analysis of variance, P < .05). The 5% NaOCl groups (G2 and G3) presented significantly lower resistance to fracture than the control (G1 and G4) (Tukey test, P < .05). Both NaOCl solutions similarly reduced the fracture resistance at approximately 30% (Tukey test, P > .05). No differences were observed between positive and negative control groups (Tukey test, P > .05).

Conclusions

Stabilized alkaline and neutral NaOCl solutions similarly reduced the fracture resistance of root canal–treated bovine teeth by about 30%.     

Temporal-controlled Release of Bovine Serum Albumin from Chitosan Nanoparticles: Effect on the Regulation of Alkaline Phosphatase Activity in Stem Cells from Apical Papilla

Introduction

The controlled delivery of bioactive molecules is crucial for the regulation of stem cell differentiation. In this study, we examined the effects of temporal-controlled release of bovine serum albumin (BSA) from chitosan nanoparticles (CSnp) to regulate the alkaline phosphatase activity (ALP) in stem cells from apical papilla (SCAP).

Methods

BSA-loaded CSnp were synthesized by 2 methods to achieve the variant temporal-controlled release: (1) the encapsulation technique (BSA-CSnpI) and (2) the adsorption technique (BSA-CSnpII). After characterization of the size, charge, and release kinetics, SCAP were cultured in the presence of these bioactive molecule–loaded nanoparticles. SCAP viability was analyzed at 1, 7, 14, 21, and 28 days, and ALP activity was analyzed every 7 days until 21 days to determine the effect of these bioactive molecule–releasing nanoparticles on the cytotoxicity and differentiation potential, respectively.

Results

BSA-CSnpI and BSA-CSnpII presented distinct in vitro release profiles of BSA in a time-controlled manner. Cell viability was significantly enhanced over time in the presence of BSA-CSnpI and BSA-CSnpII (P < .01), when compared with BSA nonloaded CSnp. ALP activity was significantly higher (P < .01) in the presence of BSA-CSnpI after 3 weeks than in BSA-CSnpII.

Conclusions

BSA-loaded CSnps were synthesized and characterized in this study. Based on the physical/chemical interaction of BSA with CSnp (encapsulation or surface adsorption), different time-controlled release profiles were observed that influenced the ALP activity of SCAP in vitro. This study highlighted the potential of temporal-controlled bioactive molecule release technology in the differentiation of stem cells in dentin pulp regeneration.     

碱性电解水对大鼠抗氧化及抗纤维蛋白原作用的实验研究

目的　探讨碱性电解水抗氧化及抗纤维蛋白原的作用。方法　W istar雄性大鼠 36只 ,分三组 ,每组 1 2只。A组 :空白对照 ,B组 :高脂模型组。 C组 :高脂 +碱性电解水组。实验结束后 ( 30 d) ,乙醚麻醉 ,腹主动脉取血 ,采用硫代巴比妥酸比色法在日本岛津 UV— 36 0分光光度计上测定丙二醛 ( MDA) ;上海斯隆纤维蛋白原测定仪测定纤维蛋白原。结果　 A、B、C三组 M DA分别为 3.39± 0 .50 ( nmol/ m1 )、4 .1 0± 0 .37及 3.6 8±0 .4 6 ;纤维蛋白原分别为 1 94 .6 3± 2 3.6 3( mg/ d1 )、2 0 1 .2 2± 2 4 .32及 1 6 9.50± 1 1 .1 7。 C组比 B组显著下降 ( P<0 .0 5)。结论　碱性电解水具有一定抗氧化及降低纤维蛋白原的功能。     

水中钙镁离子浓度与氟暴露人群血清碱性磷酸酶的研究

目的 研究人群血清AKP与饮用水中氟钙镁的关系,探讨钙镁联合作用对人群氟中毒效应指标的影响.方法 氟离子选择电极法测定水氟尿氟浓度,火焰原子分光光度法测定水钙水镁含量,金氏法测定血清AKP含量.采用多元线性回归法分析上述指标间的关系.结果 氟病区水氟水镁浓度均高于对照区,差异有统计学意义(P＜0.05),两区水钙浓度、水质总硬度差异无统计学意义(P＞0.05);病区人群尿氟均值、血清AKP明显高于对照区(P＜0.05).血清AKP与水氟水钙水镁之间的回归方程是Y=13.805 1.812X1-0.046X2-0.090X3.结论 饮用水中氟钙镁离子显著影响该地区人群血清AKP活性,钙镁联合作用可减轻或延缓机体氟中毒的骨相损害.     

精神病人伴骨折与正常骨折患者的骨矿物质含量对照研究

目的:探讨精神病人伴骨折患者是否存在骨质疏松、血清无机盐指标和血清总碱性磷酸酶(ALP)等骨矿物质含量的异常。方法:采用病例对照对36例精神病人伴骨折患者与38例正常骨折病人进行研究,测定血清K 、Na 、Ca2 等无机盐、血清总碱性磷酸酶(ALP)和检测骨密度作为诊断骨质疏松的指标进行比较。结果:与正常对照组比较,患者组患骨质疏松的比例明显增高X2=4.252,P=0.039;患者组钠和钾含量与对照组无明显差异,ALP含量明显高于对照组(P<0.05),钙含量明显低于对照组(P<0.05)。结论:精神病人容易患骨质疏松和出现低钙,是骨折发生的高危人群。     

西那卡塞联合骨化三醇注射液治疗维持性血液透析患者中重度继发性甲状旁腺功能亢进的效果观察

目的 观察西那卡塞联合骨化三醇注射液治疗维持性血液透析(maintenance hemodialysis,MHD)患者中重度继发性甲状旁腺功能亢进(secondary hyperparathyroidism,SHPT)的效果及安全性.方法 选择2017年1月—2020年1月在我院血液透析室行MHD治疗的中重度SHPT患...     

加味温经汤联合阿仑膦酸钠片治疗肾阳亏虚型绝经后骨质疏松症临床研究

目的:观察加味温经汤联合阿仑膦酸钠片治疗肾阳亏虚型绝经后骨质疏松症(PMOP)的临床疗效。方法:选取150例肾阳亏虚型PMOP患者,按随机数字表法分为对照组和观察组各75例。对照组给予口服阿仑膦酸钠片治疗,观察组在对照组基础上加服加味温经汤,2组均治疗6个月。对比2组总体疗效、治疗前后碱性磷酸酶(ALP),血钙(Ca)、磷(P),雌二醇(E2),促卵泡雌素(FSH),促黄体生成素(LH)水平,记录治疗过程中不良反应发生情况。结果:观察组总有效率96.0%,对照组总有效率80.0%,2组比较,差异有统计学意义(P<0.05)。治疗后,2组ALP水平均较治疗前降低(P<0.05),血Ca含量均较治疗前增加(P<0.05);观察组ALP水平低于对照组(P<0.05),血Ca含量高于对照组(P<0.05)。治疗后,2组E2水平均较治疗前升高,FSH及LH水平均较治疗前降低,差异均有统计学意义(P<0.05);观察组E2水平高于对照组,差异有统计学意义(P<0.05)。2组血常规异常、肝肾功能异常、消化道症状、皮肤过敏发生率比较,差异均无统计学意义(P>0.05)。结论:加味温经汤治疗肾阳亏虚型PMOP,能有效改善患者的临床症状和性激素水平,用药安全性高。