生物体活性梯度功能材料

讨论了人工生物活性梯度功能材料之现状,展望了其发展趋势。     

梯度相位检测在医学图像小波边缘提取中的应用

针对小波变换不能涉及过多尺度的问题，分析了边缘类型对小波多尺度边缘提取的影响，并结合医学图像的特点，提出基于Canny算子的梯度相位法。梯度相位法认为边缘不只是在灰度发生突变的地方存在，如果某个区域，灰度沿某个方向缓慢变化。这个区域也存在边缘，只不过可以认为边缘比较粗。通过对人脑后颅骨的CT医学图像边缘提取的实验及结果定量和定性分析，证明此方法在医学罔像边缘检测中是切实可行的。     

体外诱导小鼠骨髓单个核细胞向内皮分化的实验研究

目的:为组织工程研究做准备,分离培养小鼠骨髓单个核细胞并诱导向血管内皮分化。方法:成年Balb/c小鼠,应用淋巴细胞分离液(密度1.077g/m l),将长骨骨髓经F icoll非连续密度梯度离心,收集中层的单个核细胞,加入诱导培养基并置于纤维连接素包被的培养板上进行诱导分化,观察细胞生长状况,以透射电镜及Ⅷ因子、CD31、Lectin免疫组化以及流式细胞仪方法对培养细胞进行鉴定。结果:细胞圆形、纺锤形单层融合贴壁生长;Ⅷ因子、CD31、Lectin免疫组化染色阳性;透射电镜显示细胞具有内皮特征性的W-P小体。结论:采用F icoll密度梯度离心可获得较高纯度的骨髓单个核细胞,经体外培养并诱导分化,具有血管内皮细胞的特征。     

主动载药法制备两亲性药物脂质体的研究进展

脂质体跨膜梯度主动载药方法主要有pH梯度法和硫酸铵梯度法.本文介绍了两亲性药物脂质体跨膜梯度载药方法的原理、制备工艺、影响包封率的因素等国内外研究进展.     

pH依赖型万氏牛黄清心缓释胶囊的制备与体外释放

分别以HPMC和pH依赖型丙烯酸树脂(Eudragit)的肠溶水分散体为包衣材料制备了3种微丸.结果表明,当Eudragit L30D-55包衣增重达30%,L100/S100混合物(1∶5)增重达40%,可达到较好的抗胃溶作用,并分别在预定的pH条件下溶解.3种微丸混合制得的万氏牛黄清心缓释胶囊,体外呈现出pH依赖型的梯度脉冲释药行为.     

银黄胶囊质量标准研究

目的:建立银黄胶囊质量标准.方法:C1s柱(Hypersil ODS Agilent,4.6×200mm,5μm),流动相:甲醇与0.1%磷酸溶液进行梯度洗脱,检测波长为318mm,流速为1ml·min-1,柱温为室温.结果:绿原酸加样回收率为99.37%;RSD为0.35%;黄芩苷加样回收率为100.17%,RSD为1.23%.结论:方法简便、准确,可用于银黄胶囊的质量控制.     

中国人眼颅压力梯度参考区间的临床研究

目的探讨中国人群眼颅压力梯度参考区间,为建立基于眼颅压力梯度的开角型青光眼诊疗新体系提供理论标准。 方法横断面研究。对2010年8月至2019年8月首都医科大学附属北京同仁医院神经内科需行腰椎穿刺的受试者共200例。其中,男性97例,女性103例,年龄区间12~79岁,平均(47.0±14.7)岁。对受试者进行眼压、颅压及全身基本参数测量。性别资料采用频数和百分比描述;年龄、身高、体重、眼压、颅内压、平均动脉压、体质指数及眼颅压力梯度等连续定量资料采用 ±s描述。对于少量缺失数据,采用马尔科夫链蒙特卡洛模拟(MCMC)对缺失数据进行多重插补。采用95%分位数法确定参考值范围,对于连续定量资料的多组间比较采用单因素方差分析,两两比较采用两独立样本t检验。 结果根据全体受试者测定人群眼压参考区间为9.015 mmHg~20.265 mmHg(1 mmHg＝0.133 kPa)。人群颅压参考区间为6.179 mmHg~14.921 mmHg。人群眼颅压力梯度参考区间为-2.987 mmHg~11.047 mmHg。眼颅压力梯度临床诊疗参考区间为0.423 mmHg~10.508 mmHg。以年龄进行分组,<30岁人群眼颅压力梯度参考区间为-2.968 mmHg~9.028 mmHg;30岁~50岁人群眼颅压力梯度参考区间为-2.466 mmHg~11.606 mmHg;>50岁人群眼颅压力梯度参考区间为-2.466 mmHg~11.606 mmHg。三组间眼颅压力梯度差异无统计学意义(F＝2.041,P>0.05)。以性别进行分组,男性眼颅压力梯度参考区间为-2.769 mmHg~10.089 mmHg;女性眼颅压力梯度参考区间为-3.137 mmHg~11.877 mmHg。两组间眼颅压力梯度的差异无统计学意义(t＝-1.413,P>0.05)。以体质指数(BMI)进行分组,BMI<21 kg/m²的人群眼颅压力梯度参考区间为-1.437 mmHg~11.577 mmHg;21 kg/m²2的人群眼颅压力梯度参考区间为-3.046 mmHg~11.026 mmHg;BMI>23 kg/m²的人群眼颅压力梯度参考区间为-3.947 mmHg~10.087 mmHg。不同BMI分组间,眼颅压力梯度差异有统计学意义(F＝6.109,P<0.05)。 结论眼颅压力梯度临床诊疗参考区间为0.423 mmHg~10.508 mmHg,可作为开角型青光眼临床诊疗的新指标。同时,还为开角型青光眼病因学诊断及个体化治疗的进一步深入研究,提供新的实践基础与研究方向。     

Sedimentation and resuspendability evaluation of pharmaceutical suspensions by low-field one dimensional pulsed field gradient NMR profilometry

In order to study the sedimentation of pharmaceutical suspensions using low-field one dimensional pulsed field gradient nuclear magnetic resonance (1D pfg NMR) profilometry, the accuracy of signal acquisition as well as the spatial resolution of a commercial spectrometer operating at 23.4?MHz was investigated. The use of a solid Teflon spacer revealed that the accuracy of signal acquisition was independent of spatial position (height). The standard deviation of distance determinations was less than 150 µm, whereas the accuracy of water content determination was within 2% in the central part of the detection zone and deteriorated to 4% in the outer parts. The study of aqueous paramagnetic MnCl₂ solutions indicated an exponential relationship between the relative signal intensity and the transverse relaxation decay constant. From this relationship, the relative water content of suspensions could be derived from their signal intensity relative to that of water. Using concentrated paliperidone palmitate dispersions as model suspensions, low-field 1D pfg NMR profilometry has been proven to be suitable for the evaluation of both the sedimentation and resuspendability behavior of viscous, opaque suspensions, for which visual detection of homogeneity may be difficult.     

Effect of Transmural Extent of the Simulated Infarction in a Left Ventricular Model on Displacement and Strain Distribution Estimated from Synthetic Ultrasonic Data

The identification of a sub-endocardial infarction is of major interest in cardiology. This study evaluates the sensitivity of selected measures to the thickness of such an infarction. Synthetic ultrasonic data (long-axis view) of left ventricular models with inclusions were generated using Field II and meshes obtained from finite-element simulations, which also provided the reference for the estimates obtained from ultrasonic data. The displacements, the first and second component of the principal strain (ε₁ and ε₂), and several measures derived from these quantities were estimated. All estimates, except for the poorly estimated ε₂, exhibited sensitivity to the presence and transmurality of the inclusion. The most sensitive was the gradient of the averaged transmural profiles of ε₁, and ε₁ averaged over the area corresponding to the transmural inclusion. The inflection point of the ε₁ profile shifted toward the outer wall with increasing thickness of the non-transmural inclusion.