HPLC-MS/MS同时测定广金钱草中8种成分在大鼠胆汁中的浓度及其排泄动力学研究

建立同时测定灌胃给予大鼠广金钱草提取物后胆汁中7种黄酮和1种酚酸类化合物浓度的HPLC-MS/MS,并用于胆汁排泄研究。大鼠灌胃给予广金钱草提取物后,分别在0~1,1~2,2~4,4~6,6~8,8~12,12~24 h时间段收集胆汁。色谱柱采用Diamonsil C18column(4.6 mm×150 mm,5μm),柱温40℃。以甲醇-0.01%乙酸水溶液为流动相,梯度洗脱,流速0.8 m L·min~(-1)。质谱采用电喷雾离子源(ESI),负离子模式下检测,多反应离子监测(MRM)模式进行定量。结果表明8种成分在测定浓度范围内线性关系良好(r≥0.991 5),日内、日间精密度RSD15%,准确度RE-15%~15%,稳定性良好。提取回收率63.2%,内标归一化的基质因子RSD均未超过15%,符合要求。大鼠胆汁排泄研究结果显示,8种成分在胆汁中的原型排泄率均比较小,并且不同个体之间差别较大。该研究方法灵敏度高,选择性好,样品处理简单,可用于灌胃给予大鼠广金钱草提取物后胆汁中8种成分的排泄动力学研究。     

岷当归有效成分对高同型半胱氨酸血症兔TXB_2的影响

目的:探讨岷当归有效成分(当归挥发油、当归多糖、阿魏酸)对高同型半胱氨酸血症(HHcy)兔致动脉粥样硬化(AS)的影响。方法:将48只日本大耳白兔随机分为正常组、模型组、当归挥发油组、当归多糖组、阿魏酸组和叶酸对照组,每组8只。采用L-蛋氨酸皮下注射法建立HHcy家兔模型。造模8周后,当归挥发油组、当归多糖组、阿魏酸组分别给予岷当归有效成分灌胃治疗,叶酸组给予叶酸+维生素B_6+维生素B_(12)灌胃治疗。12周后检测各组血清同型半胱氨酸(Hcy)、血浆血栓素B_2(TXB_2)水平。结果:模型组血清Hcy水平高于正常组,差异有统计学意义(P0.05),HHcy模型形成;与模型组比较,当归挥发油组、阿魏酸组、叶酸组血清Hcy水平明显降低,差异有统计学意义(P0.05);与模型组比较,叶酸组、当归挥发油组、当归多糖组、阿魏酸组血浆TXB2水平降低,差异有统计学意义(P0.05)。阿魏酸组血浆TXB_2水平比叶酸组、当归挥发油组、当归多糖组较低,差异有统计学意义(P0.05)。结论:岷当归有效成分阿魏酸能够降低血清Hcy与血浆TXB2水平,减少Hcy对血管内皮的损伤及毒性作用。     

Attachment of gold nanoparticles to glassy carbon electrode and its application for the voltammetric resolution of ascorbic acid and dopamine

Gold nanoparticles have been attached on glassy carbon electrode surface through sulfhydryl-terminated monolayer and the gold nanoparticles-immobilized glassy carbon electrodes have been applied to the electrocatalytic oxidation of ascorbic acid, reducing the overpotential by about 200 mV with obviously increased current response. Due to its strong electrocatalytic activity towards ascorbic acid, the gold nanoparticles modified electrode can resolve the overlapped voltammetric waves of ascorbic acid and dopamine into two well-defined voltammetric peaks with peak-to-peak separation in potentials of about 300 mV. This can be used to allow the selective determination of ascorbic acid in the presence of dopamine. The catalytic current obtained from differential pulse voltammetry is linearly dependent on ascorbic acid concentration over the range of 6.5 × 10^?6 to 1.45 × 10^?4 M with correlation coefficient of 0.998 in the presence of dopamine. The detection limit (3σ) for AA was found to be 2.8 × 10^?6 M. The simultaneous determination of ascorbic acid and dopamine in their binary mixture has also been investigated. The modified electrode shows good selectivity, stability and anti-fouling properties. The proposed methods have been used for the selective determination of ascorbic acid in the presence of dopamine and for the simultaneous determination of both them in their mixtures with satisfactory results.     

Diclofenac in hyaluronic acid gel: an alternative treatment for actinic cheilitis

Objective

Actinic cheilitis (AC) is a precancerous lesion of the lip vermillion caused by prolonged exposure to ultraviolet light. The aim of this study was to evaluate the effect of 3% diclofenac in 2.5% hyaluronic acid gel in the treatment of AC.

Methods

Thirty-four patients with chronic AC were treated twice a day with topical diclofenac during a period of 30 to 180 days. The individuals were followed up every 15 days by means of clinical examination and digital photographic documentation.

Results

Of the 27 patients that completed the study, 12 (44%) showed complete remission of the whitish plaques and exfoliative areas, and 15 (56%) had partial remission of the clinical picture of cheilitis. The latter group was submitted to excision of the leukoplakic areas which diagnosis varied from mild to moderate epithelial dysplasia.

Conclusion

The results suggest a promising role for diclofenac in hyaluronic acid gel in the treatment of AC. This treatment has the advantages of not being invasive and showing few side effects.     

An In Vitro Investigation of a Comparison of Bond Strengths of Composite to Etched and Air-Abraded Human Enamel Surfaces

PURPOSE: The purposes of the study were to measure the tensile bond strength of composite resin to human enamel specimens that had been either etched or air-abraded, and to compare the quality of the marginal seal, through the assessment of microleakage, of composite resin to human enamel specimens that had been either etched or air-abraded. MATERIALS AND METHODS: Thirty mandibular molar teeth were decoronated and sectioned mesio-distally to produce six groups, each containing ten specimens that were embedded in acrylic resin using a jig. In each of the four treatment groups, the specimen surfaces were treated by either abrasion with 27 or 50 microm alumina at 4 mm or 20 mm distance, and a composite resin was bonded to the treated surfaces in a standardized manner. In the two control groups the specimens were treated with 15 seconds exposure to 36% phosphoric acid gel and then similarly treated before being stored in sterile water for 1 week. All specimens were then subjected to tensile bond strength testing at either 1 or 5 mm/min crosshead speed. For the microleakage study, the degree of dye penetration was measured 32 times for each treatment group, using a neutral methylene blue dye at the interface between composite and either 27 or 50 microm air-abraded tooth structure or etched enamel surfaces. RESULTS: The mean bond strength values recorded for Group 1 (phosphoric acid etch, 5 mm/min crosshead speed) was 25.4 MPa; Group 2 (phosphoric acid etch, 1 mm/min), 22.2 MPa; Group 3 (27 microm alumina at 4 mm distance), 16.8 MPa; Group 4 (50 microm alumina at 4 mm distance), 16.9 MPa; Group 5 (27 microm alumina at 20 mm distance), 4.2 MPa; and for Group 6 (50 microm alumina at 20 mm distance) 3.4 MPa. An analysis of variance (ANOVA) demonstrated significant differences among the groups, and a multiple comparison test (Tukey) demonstrated that conventionally etched specimens had a greater bond strength than air-abraded specimen groups. No significant difference in dye penetration could be demonstrated among the groups (p= 0.58). CONCLUSIONS: Composite resin applied to enamel surfaces prepared using an acid etch procedure exhibited higher bond strengths than those prepared with air abrasion technology. The abrasion particle size did not affect the bond strength produced, but the latter was adversely affected by the distance of the air abrasion nozzle from the enamel surface. The crosshead speed of the bond testing apparatus had no effect on the bond strengths recorded. The marginal seal of composite to prepared enamel was unaffected by the method of enamel preparation.     

Osteoclast formation from mouse bone marrow cells on micro/nano-scale patterned surfaces

ObjectivesOsteoclasts can sense the surface topography of materials. However, it is difficult to identify the structural factors that affect osteoclast formation and its function. Furthermore, we hypothesized that the type of osteoclast precursor cells also affects osteoclastogenesis in the materials. In this study, we investigated the effects of defined micro/nanoscale patterns on osteoclastogenesis from bone marrow cells (BMCs).MethodsVarious cyclo-olefin polymer (COP) patterns were prepared using nanoimprinting. The effects of shape, size, and height of the patterns, and the wettability of the patterned surfaces on osteoclastogenesis from BMCs were evaluated in vitro.ResultsOsteoclast formation was promoted on pillars (diameter, 1 μm or 500 nm; height, 500 nm). Notably, osteoclastogenesis from BMCs was better promoted on hydrophobic pillars than on hydrophilic pillars. In contrast, decreased osteoclast formation was observed on the nanopillars (diameter, 100 nm; height, 200 nm).ConclusionsWe demonstrated the promotion of osteoclast formation from BMCs on hydrophobic pillars with diameters of 1 μm and 500 nm. Some cellular behaviors in the patterns were dependent on the type of osteoclast precursor cells. The designed patterns are useful for designing the surface of dental implants or bone replacement materials with a controllable balance between osteoblast and osteoclast activities.     

五倍子对釉质抗酸蚀作用的实验研究

目的：观察中药五倍子对釉质抗酸蚀作用的效果。方法：采用500g/L五倍子水浸剂为实验组，去离子水为阴性对照，20g／L氟化钠为阳性对照，对60个正常离体牙釉质表面进行处理，制备人工龋模型，用硬组织切片机制备100μm原切片，通过显微放射照射系统观察测量五倍子对釉质的抗酸蚀作用效果。结果：500g／L五倍子水浸剂组较去离子水对照组脱矿少（P〈0．05），与20g／L氟化钠对照组相比无显著差异（P〉0．05）。结论：500g／L五倍子水浸剂可明显增强釉质抗酸蚀能力，其效果与20g／L氟化钠相当。     

Evidence of chemisorption of maleic acid to enamel and hydroxyapatite

Maleic acid has been used as an etchant or non-rinse conditioner in adhesive dentistry. However, the inherent mechanisms of the interaction of maleic acid with hydroxyapatite/enamel have never been fully elucidated. The purpose of this study was to provide evidence for the chemisorption of maleic acid onto hydroxyapatite/enamel, and to identify the reaction products obtained following the interaction of maleic acid with hydroxyapatite. Hydroxyapatite particles were dissolved in a 15% (w/v) aqueous solution of maleic acid (pH = 0.98). Half of the solution was dried to obtain a desiccated mixture. This mixture, hydroxyapatite, maleic acid and self-prepared calcium maleate were analysed by X-ray diffraction (XRD). Acetone was added to the other half of the solution to obtain a precipitate. This precipitate, hydroxyapatite, maleic acid, unetched enamel and maleic acid-etched enamel were analysed by X-ray photoelectron spectroscopy (XPS). The precipitate was also analysed by (1)H NMR. A new binding energy, indicating carboxylate groups, was detected by XPS on the precipitate and maleic acid-etched enamel surface. XRD data indicated the formation of calcium maleate and calcium hydrogen phosphate after the reaction. NMR data revealed that one carboxylic group of maleic acid reacted with hydroxyapatite. Hence, maleic acid can chemisorb to hydroxyapatite and enamel via ionic interactions.