血液环境下Biodentine与MTA的颜色稳定性研究

目的比较牙体牙髓治疗中常用的骨水泥材料Biodentine与三氧化矿物凝聚体(mineral trioxide aggregrate,MTA)在与血液接触条件下的颜色稳定性,并探讨其可能的变色原因。方法制备直径5 mm、高3 mm的Biodentine和MTA圆盘,将每种材料的24个圆盘随机分配到去离子水组和脱纤维羊血组中,浸泡1 d和7 d后进行后续检测。进行各类检测的3个时间点为:圆盘固化脱模后即刻、浸泡1 d和7 d后。检测指标如下:在同样光照环境下对圆盘进行拍照,直观比较两种材料的颜色变化;采用比色仪检测两种材料的色度;借助扫描电镜观察两种材料的表面形态;使用X射线能谱仪测量两种材料各元素含量。结果肉眼观察到与脱膜后即刻相比,在脱纤维羊血组浸泡1 d后仅MTA在明暗度上发生改变,脱纤维羊血组浸泡7 d后Biodentine与MTA颜色均加深变红,但MTA暗度明显增加。比色仪结果显示脱纤维羊血组MTA的7 d色差值ΔE(21.257±0.955)大于Biodentine的7 dΔE(5.833±0.501)(t=24.781,P<0.001);MTA材料自身变色随着与血液接触时间延长而加深,其7 dΔE与1 dΔE(6.233±0.888)相比,差异具有统计学意义(t=19.956,P<0.001);而Biodentine材料自身变色随时间延长则无统计学意义[7 dΔE与1 dΔE(6.790±0.831)相比,t=1.707,P=0.163]。扫描电镜结果表明:用脱纤维羊血浸泡7 d后,MTA表面孔隙率大于Biodentine,且MTA的晶体边缘相较Biodentine也更为圆钝。X射线能谱仪检测显示:在脱纤维羊血组浸泡7 d后MTA中氧元素含量下降、铋元素含量上升;与此同时Biodentine因阻射能力低未被检测出锆元素,但其他元素含量稳定。结论Biodentine在与血液接触条件下的颜色稳定性优于MTA,这主要与Biodentine表面孔隙率小、阻射剂成分稳定有关。     

超声图像定量分析对子宫内膜癌的诊断价值

目的观察子宫内膜癌与非子宫内膜癌的子宫内膜超声图像回声强度的差异,探讨超声图像定量分析对子宫内膜癌的诊断价值。方法选择绝经后不规则阴道流血的患者84例和健康体检正常的绝经期妇女30例(健康组),通过联合应用彩色多普勒超声诊断仪与超声图像定量分析仪检测其子宫内膜回声强度定量指标,并检测子宫内膜厚度。84例患者同时进行病理学检查,根据病理结果分为内膜增生组(48例)、内膜癌组(36例),比较各组间灰阶值及分贝值的差异。结果内膜癌组的子宫内膜厚度、灰阶值及分贝值均高于内膜增生组和健康组(P均0.01),内膜增生组的子宫内膜厚度、灰阶值及分贝值均高于健康组(P0.05或0.01)。结论超声图像定量分析提供了超声影像的数字量化指标,结合子宫内膜厚度,为无创鉴别子宫内膜癌提供了得力手段。     

Polysaccharide Biocatalysis: From Synthesizing Carbohydrate Standards to Establishing Characterization Methods

Starch, glycogen, and cellulose are all around us. They are eaten and used on a daily basis but they are not understood completely. Even though these carbohydrates are simple, concerning their repeating unit, they are hard to characterize. In order to try to understand as much as possible about their structure and the relationship between their molecular structure and physical properties, it is very practical to create such polysaccharides, for instance enzymatically, characterize them, and use them as standards for the characterization of natural ones. Therefore, the main objective of this Trend article is to outline different enzymatic routes to such carbohydrates, possibilities for their characterization, and the characterization of natural ones.     

肺癌肿瘤干细胞的分选及生物学特性

目的 探讨肺癌肿瘤干细胞分选及生物学特性的研究方法。方法 采用免疫磁珠分选经盐酸阿霉素(ADM)诱导的人肺腺癌SPC-A-1(SPC-A-1/ADM)细胞系中的ABCG2 ⁺和ABCG2 ^-细胞,流式细胞术和裸鼠体内移植针对ABCG2 ⁺和ABCG2 ^-细胞体内的成瘤率进行测定分析。结果 SPC-A-1细胞中的荧光强度平均为(1.001±0.014)×10 ²,明显低于SPC-A-1/ADM细胞的(10.257±0.023)×10 ²(t=17.320,P=0.001)。SPC-A-1细胞ABCG2/BCRP-FITC处理组与SPC-A-1细胞对照组(t=5.269,P=0.021)和SPC-A-1细胞同型对照组(t=6.869,P=0.012)间差异有统计学意义;SPC-A-1/ADM细胞对照组与SPC-A-1/ADM细胞同型对照组间差异有统计学意义(t=8.112,P=0.015)。SPC-A-1/ADM 细胞 ABCG2/BCRP-FITC 处理组阳性率为9.8%,是SPC-A-1细胞组的39.84倍。SPC-A-1/ADM 细胞 ABCG2/BCRP-FITC 处理组与SPC-A-1/ADM细胞组(t=9.120,P=0.005)和SPC-A-1/ADM细胞同型组(t=8.257,P=0.006)间差异有统计学意义。B 群细胞阳性率是 A 群细胞的 684 倍,差异有统计学意义(t=11.235,P=0.001),且 B 群细胞的荧光强度较强。接种SPC-A-1 细胞、A群细胞和B 群细胞的裸鼠平均成瘤体积分别为(6.96±1.82)、(6.70±2.55)和(9.17±2.41)mm ³,以接种B群细胞组最高,但3组间差异无统计学意义(F=2.362,P=0.086)。接种B群细胞组的成瘤率为75.00%,明显高于SPC-A-1 细胞组和A 群细胞组(F =19.780,P=0.002)。结论 ABCG2抗体与免疫磁珠分选法结合可以从人肺腺癌 SPC-A-1/ADM 细胞系内分离ABCG2 ⁺细胞,其在裸鼠体内成瘤情况良好,可用于肺癌肿瘤干细胞的分选及生物学特性研究。     

麦角甾苷固体脂质纳米粒处方筛选和理化性质研究

目的 研究不同种类药用辅料成分对麦角甾苷固体脂质纳米粒（SLN）理化性质的影响,为研究SLN的处方筛选提供依据。方法 采用乳化-固化法制备麦角甾苷-SLN,单一变量法考察山嵛酸甘油酯（Compritol ATO 888）、单硬脂酸甘油酯、大豆卵磷脂、Myrj52等辅料对麦角甾苷-SLN粒径、包封率、表征分散度（PDI）等理化性质的影响,采用透射电镜法观察麦角甾苷-SLN的形态,X-射线衍射（XRD）分析其药物晶体结构。结果 随Compritol ATO 888用量增加,麦角甾苷-SLN粒径不断减小,包封率逐渐减小,PDI逐渐增加;随单硬脂酸甘油酯的用量增加,粒径明显增大,包封率略有降低,PDI减小;随卵磷脂用量增加,粒径明显增大,包封率降低,PDI减小;随Myrj52用量明显增加,粒径减小,包封率增加,PDI增大;麦角甾苷-SLN外观圆整,呈球形;麦角甾苷以分子分散状态被包裹在SLN中。结论 不同辅料对麦角甾苷-SLN的理化性质均产生一定影响趋势,为制备SLN的处方筛选研究提供启示与思路。     

Influence of Tricuspid Bioprosthetic Mitral Valve Orientation Regarding the Flow Field Inside the Left Ventricle: In Vitro Hydrodynamic Characterization Based on 2D PIV Measurements

The flow patterns of a prosthetic heart valve in the aortic or mitral position can change according to its type and orientation. This work describes the use of 2D particle image velocimetry (PIV) applied to the in vitro flow fields characterization inside the upper part of a left ventricular model at various heart rates and as a function of two orientations of stented tricuspid mitral bioprostheses. In the ventricular model, each mitral bioprosthesis (27 and 31 mm diameter) was installed in two orientations, rotated by 180°, while the aortic bileaflet mechanical valve (27 mm diameter) remained in a fixed orientation. The results (N = 50) showed changes in the intraventricular flow fields according to the mitral bioprostheses positioning. Also, changes in the aortic upstream velocity profiles were noticed as a function of mitral orientations.     

Investigation of Ethylene Oxide-co-propylene Oxide for Dissolution Enhancement of Hot-Melt Extruded Solid Dispersions

The optimal design of amorphous solid dispersion formulations requires the use of excipients to maintain supersaturation and improve physical stability to ensure shelf-life stability and better absorption during intestinal transit, respectively. Blends of excipients (surfactants and polymers) are often used within pharmaceutical products to improve the oral delivery of Biopharmaceutical Classification System class II drugs. Therefore, in this study, a dissolution enhancer, poloxamer 407 (P407), was investigated to determine its effect on the dissolution properties and on the amorphous nature of the active pharmaceutical ingredient contained in the formulation. Phase solubility studies of indomethacin (INM) in aqueous solutions of P407 and poly(vinylpyrrolidone-vinyl acetate copolymer) showed an increase in the kinetic solubility of INM compared with the pure drug at 37°C with a K_a value of 0.041 μg/mL. The solid dispersions showed a higher dissolution rate when compared to pure and amorphous drugs when performed in pH buffer 1.2 with a kinetic solubility of 21 μg/mL. The stability data showed that the amorphous drug in solid solutions with poly(vinylpyrrolidone-vinyl acetate copolymer) and P407 remained amorphous, and the %P407 loading had no effect on the amorphous stability of INM. This study concluded that the amorphous solid dispersion contributed to the increased solubility of INM.     

Measurement of Average Aggregate Density by Sedimentation and Brownian Motion Analysis

The spatially averaged density of protein aggregates is an important parameter that can be used to relate size distributions measured by orthogonal methods, to characterize protein particles, and perhaps to estimate the amount of protein in aggregate form in a sample. We obtained a series of images of protein aggregates exhibiting Brownian diffusion while settling under the influence of gravity in a sealed capillary. The aggregates were formed by stir-stressing a monoclonal antibody (NISTmAb). Image processing yielded particle tracks, which were then examined to determine settling velocity and hydrodynamic diameter down to 1 μm based on mean square displacement analysis. Measurements on polystyrene calibration microspheres ranging in size from 1 to 5 μm showed that the mean square displacement diameter had improved accuracy over the diameter derived from imaged particle area, suggesting a future method for correcting size distributions based on imaging. Stokes' law was used to estimate the density of each particle. It was found that the aggregates were highly porous with density decreasing from 1.080 to 1.028 g/cm³ as the size increased from 1.37 to 4.9 μm.