HPLC方法同时测定九里香中的三个主要成分(英文)

九里香是传统中药九里香属植物的两个基原植物之一。本研究建立了一种快速、有效的HPLC分析方法,能够实现在20分钟内同时测定九里香中两个香豆素类化合物,海南九里香内酯(1)和橙皮内酯(2),以及一个多甲氧基黄酮类化合物,3,5,6,7,3′,4′,5′-七甲氧基黄酮(3)。色谱条件为采用DIKMA Spursil C18色谱柱,乙腈–水(50:50,v/v)等度洗脱,柱温25 oC,流速1 m L/min,320 nm检测。三个主要成分分离度良好,在测试范围内线性关系良好,r>0.999;精密度、重复性、稳定性良好;平均加样回收率在100.52%–101.97%之间,RSD值小于2%。采用该方法对20批不同产地的九里香药材进行含量测定,三个主要成分的含量和在1.55–7.45 mg/g。此外,还对九里香不同部位如主茎、侧枝、嫩枝和叶,及不同采收期的药材进行了测定。结果表明,三个主要成分在嫩枝及叶中的含量明显高于主茎或侧枝中,所以药典规定以九里香的叶及嫩枝作为药用部位是合理的;六月或十月为最佳采收期;产自广东茂名市、深圳市、广西南宁市、天峨市和福建漳州市的九里香中主要活性成分的含量高于其他产地。该方法具有高效、简便的特点,可用于九里香药材及其相关产品的质量控制。     

面部对称性的量化研究和临床应用

目的探索面部器官的对称性和形态学特征,为面部的修复重建、美容整形手术提供依据。方法随机选择50例正常青年女性,采用计算机辅助的照片测量法,测量面部的对称距离及角度,观察测量数据的差异和变化。然后选出10例,用计算机制作其侧面部合成图,并和原图进行评分比较。两次实验均用SAS软件进行统计分析。结果内外眦连线和水平线的夹角、眉头眉峰连线和水平线的夹角、鼻翼点到口角点间距、口角点到下颌角点间距,以及下颌角点到软组织颏下点间距,在左右两侧面部的测量值有统计学差异。左右两侧面部合成图的评分分值明显小于被测者原先照片的评分值。结论中下面部组织的不对称性较为明显。面部的绝对对称是不存在的。对称性的概念不能独立而单一地应用于人体美学中。面部对称形态特征的标准化研究和范围界定还有待进一步的探索。     

Four-dimensional flow magnetic resonance imaging in cirrhosis

Since its introduction in the 1970’s, magnetic resonance imaging (MRI) has become a standard imaging modality. With its broad and standardized application, it is firmly established in the clinical routine and an essential element in cardiovascular and abdominal imaging. In addition to sonography and computer tomography, MRI is a valuable tool for diagnosing cardiovascular and abdominal diseases, for determining disease severity, and for assessing therapeutic success. MRI techniques have improved over the last few decades, revealing not just morphologic information, but functional information about perfusion, diffusion and hemodynamics as well. Four-dimensional (4D) flow MRI, a time-resolved phase contrast-MRI with three-dimensional (3D) anatomic coverage and velocity encoding along all three flow directions has been used to comprehensively assess complex cardiovascular hemodynamics in multiple regions of the body. The technique enables visualization of 3D blood flow patterns and retrospective quantification of blood flow parameters in a region of interest. Over the last few years, 4D flow MRI has been increasingly performed in the abdominal region. By applying different acceleration techniques, taking 4D flow MRI measurements has dropped to a reasonable scanning time of 8 to 12 min. These new developments have encouraged a growing number of patient studies in the literature validating the technique’s potential for enhanced evaluation of blood flow parameters within the liver’s complex vascular system. The purpose of this review article is to broaden our understanding of 4D flow MRI for the assessment of liver hemodynamics by providing insights into acquisition, data analysis, visualization and quantification. Furthermore, in this article we highlight its development, focussing on the clinical application of the technique.     

Linearity study on detection and quantification limits for the determination of avermectins using linear regression

In this study, linear relationships between response and concentration were used to estimate the detection limit (DL) and quantification limit (QL) for five avermectins: emamectin, abamectin, doramectin, moxidectin, and ivermectin. Estimation of DL and QL was based on the standard deviation of residual and y-intercept of the regression line at low concentrations of avermectins, using the dispersive solid-phase extraction procedure. Avermectin extracts were analyzed using liquid chromatography tandem mass spectrometry. Based on the regression slope, DL and QL were higher at concentrations of 0.3–0.4 μg/kg and 1 μg/kg, respectively, for all avermectin compounds. Linearity assessment was performed by linear regression, which incorporated a regression model, outlier rejection, and evaluation of the assumption with a significant test. For all avermectins, there is a significant correlation between response and concentration in the range 1–15 μg/kg, and the y-intercept passes through origin (zero).     

The Netherlands protocol for standardisation and quantification of FDG whole body PET studies in multi-centre trials

Introduction  Several studies have shown the usefulness of positron emission tomography (PET) quantification using standardised uptake values (SUV) for diagnosis and staging, prognosis and response monitoring. Many factors affect SUV, such as patient preparation procedures, scan acquisition, image reconstruction and data analysis settings, and the variability in methodology across centres prohibits exchange of SUV data. Therefore, standardisation of 2-[¹⁸F] fluoro-2-deoxy-D-glucose (FDG) PET whole body procedures is required in multi-centre trials. Methods  A protocol for standardisation of quantitative FDG whole body PET studies in the Netherlands (NL) was defined. This protocol is based on standardisation of: (1) patient preparation; (2) matching of scan statistics by prescribing dosage as function of patient weight, scan time per bed position, percentage of bed overlap and image acquisition mode (2D or 3D); (3) matching of image resolution by prescribing reconstruction settings for each type of scanner; (4) matching of data analysis procedure by defining volume of interest methods and SUV calculations and; (5) finally, a multi-centre QC procedure is defined using a 20-cm diameter phantom for verification of scanner calibration and the NEMA NU 2 2001 Image Quality phantom for verification of activity concentration recoveries (i.e., verification of image resolution and reconstruction convergence). Discussion  This paper describes a protocol for standardization of quantitative FDG whole body multi-centre PET studies. Conclusion  The protocol was successfully implemented in the Netherlands and has been approved by the Netherlands Society of Nuclear Medicine. An erratum to this article can be found at     

In vivo Gd-DTPA concentration for MR lung perfusion measurements: Assessment with computed tomography in a porcine model

A linear relationship between MR signal and contrast-agent concentration (CAC) of the arterial-input function (AIF) is crucial for MR lung-perfusion quantification. The aim was to determine the in-vivo real maximum CAC of the AIF, using cine CT measurements in a porcine model. A dilution series (Gd-DTPA, 0-20 mM) was examined by clinical time-resolved 3D-GRE MRI and by MDCT in cine CT mode. Using the CT setup, data were acquired in five pigs immediately after the injection of 0.05 mmol and 0.07 mmol/kg BW Gd-DTPA. For phantom measurements, mean signal values were determined using a region-of-interest (ROI) analysis and for animal measurements, a ROI was placed in the pulmonary trunk of the cine CT perfusion data sets. The CT phantom measurements were used to calculate the in-vivo maximum CAC corresponding to the HU values obtained in the pulmonary trunk by the cine CT study. Linearity of the AIF of the CT perfusion measurements was verified using the MR phantom measurement results. MR phantom measurements demonstrated linearity for concentrations of 0-4 mM. CT phantom measurements showed linear relation for the entire CAC range. Comparing in-vivo and in-vitro measurements, three of five CA injections at 0.05 mmol/kg and all 0.07 mmol/kg injections exceeded the range of linearity in MRI. The CA dose for quantification of lung perfusion with time-resolved MR studies must be chosen carefully since even with low doses (0.05 mmol/kg) the CAC may exceed the range of linearity in the AIF.     

Method of ranking of heart valve characteristics at mitral position based on statistical model analysis

The purpose of this study was to explore a valve selection criterion based on the impact force generated at valve closure, and to test a statistical mathematical model for comparing valve performance. The impact force generated at valve closure in the mitral position was measured continuously, using a load cell mounted in the left atrial section of a mock circulatory system. Eight clinical valves were tested. The data obtained from the in vitro test were subjected to multiregression analysis, to enable systematic comparison of the impact forces of these valves. Further-more, class I quantification, theory was applied to construct the statistical mathematical model. As a result, the following interaction effect was observed in the statistical model. (1) The impact force generated at valve closure had a lower value in valves of smaller diameter. (2) The ranking of 29-mm-diameter valves by impact force was different for the flow region. Under the physiological flow condition of 4–61/min, high impact forces were generated in all valves, in the order Björk-Shiley monostrut, ATS, St. Jude medical, CarboMedics. We consider that low impact force at valve closure is desirable, upon consideration of the influence on the annulus tissue at valve replacement. From these findings, the results of the multiregression analysis provide indications for choosing the optimal value for patients with severe mitral insufficiency (MI).     

CT of pulmonary emphysema - current status, challenges, and future directions

Pulmonary emphysema is characterized by irreversible destruction of lung parenchyma. Emphysema is a major contributor to chronic obstructive pulmonary disease (COPD), which by itself is a major cause of morbidity and mortality in the western world. Computed tomography (CT) is an established method for the in-vivo analysis of emphysema. This review first details the pathological basis of emphysema and shows how the subtypes of emphysema can be characterized by CT. The review then shows how CT is used to quantify emphysema, and describes the requirements and foundations for quantification to be accurate. Finally, the review discusses new challenges and their potential solution, notably focused on multi-detector-row CT, and emphasizes the open questions that future research on CT of pulmonary emphysema will have to address.     

三线法在计算气胸肺压缩程度中的应用

目的:利用三线法计算气胸患者的肺压缩程度,以探索更简便、精确的估算方法。方法:分析36例气胸患者的80幅直立后前位X线片(球管距离1.5m):①分别应用体积法[(R2H-r2h)/R2H]和传统面积法[(ab-a'b')/ab]得出其肺压缩率,并比较两种方法的相关性及差异。②测量每张胸片肺萎陷后3个固定点处的脏层与壁层胸膜间距离,计算距离之和(A+B+C),并与体积法所测值进行直线回归分析,得出直线回归方程。结果:面积法与体积法所测值相关,但两者间存在差异,面积法计算肺压缩率比体积法低估约(3.95±5.16)%。根据体积法与三线法的回归分析得出,计算肺萎陷程度的公式为Y=2.20+[3.65×(A+B+C)],r=0.95,P<0.0001。结论:三线法是计算气胸肺萎陷程度方便而准确的方法,值得临床推广应用。     

Quantification of Right and Left Ventricular Volumes in Children with Congenital Heart Disease by Multidetector-Row Computed Tomography

Multidetector-row computed tomography (MDCT) of the heart is a new diagnostic approach for the quantitative evaluation of the coronary artery in adults. However, in children, the quantitative analysis of each cardiac chamber has not been established. We attempt to clarify the feasibility and validation of ECG-gated MDCT as a quantitative diagnostic tool to assess the right and left ventricular volume in children. The study consisted of 16 patients who had definite right and left ventricle. After obtaining multislice images by MDCT, we measured the end diastolic volume of both the right and the left ventricle by direct calculation of the region of interest and calculation from the projected image of three-dimensional reconstruction by traditional formulas. The correlation between the two calculations for both ventricles is excellent (r = 0.99 for LV and 0.94 for RV, respectively). The correlations for ventricular volume between calculation of catheterization and calculation of MDCT is also good (r = 0.99 for LV 0.99 for RV, respectively). Volume measurement by ECG-gated MDCT of the right and left ventricles is well correlated with that by catheterization in children and can reduce the necessity for cardiac catheterization.