微波帮助提取中药金银花中有效成分的分析

目的:分析微波帮助提取中药金银花中有效成分的可行性。方法:以中药金银花作为提取对象,采用微波帮助提取以及超声波提取法对中药金银花有效成分进行提取。采用紫外可见分光光度法进行两种方法提取效果的对比。结果:紫外可见光光度法检测结果显示微波帮助提取金银花有效成分的提取率要比超声波提取法高30.2%。微波帮助提取恒定时间为1 min、超声波提取时间为40 min。结论:微波帮助提取中药金银花中有效成分的提取效果较佳,且所需时间较短,可对中药有效成分进行快速分析。     

正交试验结合苯酚-硫酸法优选茅苍术中多糖的提取工艺

目的:优选出茅苍术中多糖成分的最佳水提取工艺。方法:采用水提醇沉法提取多糖成分,以苯酚-硫酸法测定总多糖的含量。以总多糖含量为评价指标,以提取时间、提取次数和加水量为影响因素,采用正交试验优选茅苍术中总多糖的最佳提取工艺。结果:茅苍术中多糖成分的最佳提取工艺为水提取3次,每次加水10倍量,每次提取1.0小时。结论:正交试验结合苯酚-硫酸法考察茅苍术中多糖成分的最佳水提取工艺稳定可行。     

Effects of phosphoric acid on bovine enamel bleached with carbamide peroxide

The aim of this study was to measure the demineralization capacity of 37% phosphoric acid on bovine enamel at different time-points after bleaching with 30% carbamide peroxide. Five, 4 × 4-mm sections were obtained from the enamel of 10 bovine incisors. After applying 30% carbamide peroxide (Vivastyle) for 90 min, specimens were stored in artificial saliva for 0, 24, 72 h, or 7 d and then immersed in 37% phosphoric solution. At 15, 30, 60, 90, and 120 s, 5-ml aliquots were extracted. A control group of specimens was not bleached. Ca²⁺ concentrations were measured by atomic absorption spectrophotometry. A larger amount of Ca²⁺ was extracted from enamel by phosphoric acid after the application of 30% carbamide peroxide. Twenty-four hours after bleaching, significantly more Ca²⁺ was extracted from bleached than from control specimens at all time-points, and this greater susceptibility to the action of the acid persisted for at least 1 wk after bleaching.     

Measurement of stain on extracted teeth using spectrophotometry and digital image analysis

Abstract: Aim: The aim of this study was to assess the reliability and validate a customized image analysis system, designed for use within clinical trials of general dental hygiene and whitening products, for the measurement of stain levels on extracted teeth and to compare it with reflectance spectrophotometry. Method: Twenty non‐carious extracted teeth were soaked in an artificial saliva, brushed for 1 min using an electric toothbrush and a standard toothpaste, bleached using a 5.3% hydrogen peroxide solution and cycled for 6 h daily through a tea solution. CIE L* values were obtained after each treatment step using the customized image analysis system and a reflectance spectrophotometer. A statistical analysis was carried out in SPSS. Results: Fleiss’ coefficient of reliability for intra‐operator repeatability of the image analysis system and spectrophotometry was 0.996 and 0.946 respectively. CIE L* values were consistently higher using the image analysis compared with spectrophotometry, and t‐tests for each treatment step showed significant differences (P < 0.05) for the two methods. Limits of agreement between the methods were ?27.95 to +2.07, with a 95% confidence of the difference calculated as ?14.26 to ?11.84. The combined results for all treatment steps showed a significant difference between the methods for the CIE L* values (P < 0.05). Conclusion: The image analysis system has proven to be a reliable method for assessment of changes in stain level on extracted teeth. The method has been validated against reflectance spectrophotometry. This method may be used for pilot in vitro studies/trials of oral hygiene and whitening products, before expensive in vivo tests are carried out.     

Ganglion cyst of the temporomandibular joint

We report a case of cystic lesion in a 37-year-old woman. The patient had an oval-shaped lesion adjacent to the temporomandibular joint. Thick fibrotic tissue and muscle were observed microscopically, but the epithelium lining was not observed. The lesion was diagnosed as a ganglion cyst. The patient's general medical history was non-contributory. High performance liquid chromatography (HPLC) and mass spectrophotometry (MS) revealed some proteins from the fluid in the lesion, such as a filaggrin precursor, dystroglycan, a polyprotein of the hepatitis C virus, and proteins originating from bacteria. The follow-up examinations revealed no recurrence. The probable pathogenesis of the lesion is discussed.     

不同产地药材牛膝的红外光谱及红外导数光谱鉴别研究

目的 建立不同产地牛膝的红外光谱和红外导数光谱并对其差异性进行分析,为牛膝药材的快速鉴别提供依据。方法 运用傅里叶红外光谱技术结合二阶导数光谱对不同产地的牛膝药材进行鉴别,采用聚类分析和主成分分析对红外光谱数据进行统计分析。结果 牛膝的红外吸收峰主要在3 289、2 975、2 890、1 723、1 630、1 403、1 321、1 241、1 018、927、814、773 cm-1附近,虽然不同产地牛膝所含化学成分具有相似性,但不同产地牛膝红外吸收峰的位置和相对强度存在一定差异;并且在二阶导数红外图谱的1 800~800 cm-1波段中有更加明显差别,可以为其鉴别提供更准确的依据。聚类分析显示不同批次间相似度很高,主成分分析结果表明在1 723、1 630、927、814、651 cm-1等处的吸收峰对区分不同产地牛膝药材的贡献较大,内蒙古自治区赤峰市和河南省焦作市武陟县的牛膝药材综合评分较高。结论 红外光谱法与二阶导数光谱相结合不仅可以提供中药材所含化学成分的相关信息,还可以对其不同产地进行区分,实现对牛膝的快速鉴别。     

紫外分光光度法对苯扎溴铵浓度的测定

用紫外分光光度法，于苯扎溴铵特征吸收峰的２５６ｎｍ波长下测定溶液中苯扎溴铵浓度。对苯扎溴铵浓度≤１６３２μｇ／ｍｌ的溶液，测定结果的相对标准偏差≤１７６％。     

庆大霉素-藻酸钙三维缓释微球的药物释放研究

目的研制庆大霉素一藻酸钙三维缓释微球并调控其庆大霉素的释放。使其达到长期局部抗菌的效果。方法制作不同浓度T、S、U组庆大霉素-藻酸钙缓释凝珠,与庆大霉素-骨水泥颗粒Y组进行庆大霉索释放情况比较。通过不同时间点抽取浸泡液,送紫外分光光度法（UV）及金黄色葡萄球菌（SA）培养检测,由此计算出各组包封率、释放率,绘制庆大霉素释放曲线。结果4组样品（微生物法）的包封率及30d药物释放率分别为：U组（53．99％、36．31％）,S组（39．62％、27．55％）。T组（34．20％、30．83％）,Y组（100．00％、48．49％）。U组的包封率较高,30d释放庆大霉素的总量较大,更接近Y组。4组间差异有统计学意义（P〈0．01）。U、Y组庆大霉素的释放明显高于S、T组的释放。各组30d内庆大霉素的浓度几乎都能超过金黄色葡萄球菌的最低抑菌浓度（MIC）．即〉2μg／mI。结论U组载药缓释凝珠30d内的庆大霉索释放较为理想。可作为BMSCs的三维培养支架。     

Assessment of Color Stability of White Mineral Trioxide Aggregate Angelus and Bismuth Oxide in Contact with Tooth Structure

Introduction

Dental discoloration with use of materials containing bismuth oxide has been reported. It is postulated that the discoloration is a result of chemical interaction of bismuth oxide with dentin. The aim of the study was to analyze dental color alteration and the chemical interaction of bismuth oxide with the main components present in composite (methacrylate) and in dentin (collagen).

Methods

Fifty bovine teeth were prepared and filled with white mineral trioxide aggregate (MTA) Angelus, Portland cement (PC) with 20% zirconium oxide, or PC with 20% calcium tungstate and then sealed with composite. Triple antibiotic paste and unfilled samples were the positive and negative controls, respectively. The specimens were stored in separate flasks immersed in tap water at 37°C with ambient light blocked out. The color assessment was performed with a spectrophotometer at different intervals, namely before filling and 24 hours, 15 days, and 30 days after filling. The color change and the luminosity were calculated. The statistical analysis was performed by using nonparametric Kruskal-Wallis and Dunn tests (P < .05). The interaction of the bismuth oxide, zirconium oxide, and calcium tungstate with collagen and methacrylate was assessed by placing the materials in contact, followed by color assessment.

Results

The analysis of color change values showed that all the materials presented color alteration after the evaluated periods. Statistically higher luminosity was verified for PC/20% zirconium oxide in comparison with white MTA Angelus (P < .05). The teeth filled with white MTA Angelus demonstrated a grayish discoloration with evident dentin staining. Bismuth oxide exhibited a color change when in contact with collagen.

Conclusions

The color of white MTA Angelus was altered in contact with dental structures. Collagen, which is present in dentin matrix, reacted with bismuth oxide, resulting in a grayish discoloration. The use of an alternative radiopacifier to replace bismuth in white MTA is indicated.