应用AutoCAD定量分析牙槽骨水平的研究

目的应用AutoCAD计算机辅助设计软件,建立定量分析牙槽骨水平的新方法并对其进行评价。方法用AutoCAD软件在数字曲面体层片上分别测量168颗牙釉牙骨质界到牙槽嵴顶及釉牙骨质界到根尖的面积和线性距离,计算牙槽骨吸收的面积比值和长度比值,对2种比值进行比较分析。结果用AutoCAD测量336个面积和672个线性距离,牙槽骨吸收的面积比值与长度比值之间有很高的相关一致性,Pearson相关系数为0.921(P0.001);不同操作者之间的测量结果无显著差异(P0.05),组内相关系数为0.994(P0.001),Pearson相关系数为0.988(P0.001)。结论在二维图像的X线片中,用AutoCAD软件测量牙槽骨吸收面积比值可作为定量评价牙槽骨水平的新方法。     

Analysis of heterocyclic amines in meat products by liquid chromatography – Tandem mass spectrometry

Heterocyclic amines (HCAs), a class made up of more than 25 compounds, are unintended hazardous substances that are generated by the heating or processing of proteinaceous foods at high temperatures. The International Agency for Research on Cancer (IARC) has classified four such HCAs (IQ, MeIQ, MeIQx, and PhIP) as being probable or possible human carcinogens. In this study, two sample preparation strategies, liquid–liquid extraction (LLE) with solid-phase extraction (SPE) and a rapid, easy, cheap, effective, rugged, and safe extraction (QuEChERS) method, were investigated for the determination of 11 types of HCAs in meat products by LC-MS/MS. The HCAs in the samples were first extracted with acetonitrile by LLE, and followed by SPE. In the case of QuEChERS extraction, acetonitrile is used as the LLME solvent, and PSA, C18EC and MgSO₄ were used as the dSPE sorbent. Both methods showed good performance with respect to precision (RSD < 15.15%), accuracy (79.80–117.64%), recovery (52.39–116.88%), limit of quantitation for a spiked meat extract (0.01–10 ppb) and correlation coefficients (>0.993). The QuEChERS extraction strategy provided a better linear dynamic range and superior sensitivity in comparison with the LLE-SPE approach. HCAs were successfully quantified in real samples using the two proposed approaches by LC-MS/MS.     

磁共振频谱数据定量后处理技术比较

目的 比较磁共振频谱定量的三种常用后处理软件（LCModel、SAGE、Funct001）对代谢物含量估计的准确性。方法14例健康成年人,平均年龄为26．1岁。使用STEAM序列进行定量检测,实验参数为TE：30ms,TR=3000mS。结果三种软件处理结果中除NAA／Cr外,Cho／Cr、mI／Cr的比值相互间存在差异。LCModel软件分析得到cho／Cr比值与文献偏差明显。使用Functool软件进行分析发现,NAA／Cr、ml／Cr比值与文献结果间存在偏差。使用SAGE软件对频谱的波峰下面积分析并计算出比值,得出Cho／Cr、mI／Cr与文献结果存在差异。结论使用LCModel软件对于磁共振频谱进行定量处理,在基线的拟合及系统误差处理方面较SAGE软件及Functool软件有优势,但LCModel对代谢物浓度估算仍存在误差。     

Quantitation of the tacrine analogue octahydroaminoacridine in human plasma by liquid chromatography–tandem mass spectrometry

A rapid and sensitive method based on liquid chromatography–tandem mass spectrometry (LC–MS/MS) has been developed for the determination of octahydroaminoacridine in human plasma using tramadol as internal standard (I.S.). Sample preparation involved pH adjustment with sodium carbonate followed by solvent extraction with dichloromethane:ethyl ether (40:60, v/v). Chromatographic separation was achieved on a Venusil MP-C18 column (5 μm, 100 mm × 4.6 mm) using acetonitrile:10 mM ammonium acetate:formic acid (30:70:1, v/v/v) as mobile phase. Detection utilized an API 4000 system operated in the positive ion mode with multiple reaction monitoring of the analyte at m/z 203.1 → 175.1 and of the I.S. at m/z 264.1 → 58.0. The method was linear in the range 0.01–10 ng/ml with a lower limit of quantitation of 0.01 ng/ml. Intra- and inter-day precisions measured as relative standard deviation were <3.15% and <5.01%, respectively. The method was successfully applied to a pharmacokinetic study involving oral administration of a tablet containing 4 mg octahydroaminoacridine succinate to healthy volunteers. Pharmacokinetic parameters for octahydroaminoacridine include C_max 1.19 ± 0.53 ng/ml, T_max 0.77 ± 0.17 h, AUC_0−t 3.42 ± 1.01 ng h/ml and t_1/2 2.89 ± 0.56 h.     

RETRACTED ARTICLE: The retention behavior of ginsenosides in HPLC and its application to quality assessment of Radix Ginseng

This study systematically investigated the retention behavior of seven neutral ginsenosides Rg₁, Re, Rf, Rb₁, Rb₂, Rc, Rd, and an acidic ginsenoside R₀, the major pharmacologically active components of Radix Ginseng with RP-HPLC. The effects of solvent, pH value, ionic strength of the mobile phase, and column temperature were investigated using an octadecylsiloxanebonded silica gel column. Based on the ginsenosides’ retention characteristics, the concentration of acetonitrile and the gradient of the mobile phase needed to maintain the baseline separation of the major neutral ginsenosides in Radix Ginseng were theoretically predicted. Furthermore, the ionic strength of mobile-phase necessary to achieve good resolution of the neutral ginsenosides and acidic ginsenosides was carefully investigated. According to the results of the quantitative analysis of ginsenosides in eight batches of ginseng samples from different sources, the developed HPLC technique may be a valuable tool for the quality assessment of Radix Ginseng. This article was retracted as it was printed by error in this issue of APR.     

1H-NMR法分析头孢孟多酯钠对照品

目的　测定首批对照品头孢孟多酯钠含量和头孢孟多校正因子。方法　采用 L C/ MSNMR的方法鉴定了样品中所含的主要降解产物为头孢孟多 ;选择合适的溶剂防止降解反应的发生 ,采用 NMR法测定头孢孟多酯钠和头孢孟多的含量 ,计算出头孢孟多相对于头孢孟多酯钠的校正因子 ,同时采用 L C法对测定结果进行了验证。结果　NMR与 L C含量测定及校正因子测定结果一致。结论　NMR法测定含量方法准确、简便、快速 ,NMR测定校正因子方法可行     

RT—PCR定量检测GST—πmRNA的表达

目的：建立一个用于测定临床样本中胎盘型谷胱甘肽Ｓ－转移酶（ＧＳＴ－π）ｍＲＮＡ表达水平的逆转录－聚合酶链反应（ＲＴ－ＰＣＲ）定量技术。方法：根据共扩增ＰＣＲ定量原理，通过多对引物的特异性分析和动力学筛选，建立了以β－ａｃｔｉｎ作内参，底片扫描定量的ＲＴ－ＰＣＲ法，并对３０例食管癌组织和癌旁组织ＧＳＴ－πｍＲＮＡ表达水平进行了检测。结果：本方法灵敏度高、重复性好（批内ＣＶ＜１６％；批间ＣＶ＜３０％）、不用同位素标记，ＧＳＴ－π／β－ａｃｔｉｎ比值不受肝素、ＳＤＳ等的影响。２３例食管癌组织的ＧＳＴ－πｍＲＮＡ表达水平（１．９８±０．７６）明显高于２１例癌旁组织表达水平（１．０２±０．５８）（Ｐ＜０．０１）。结论：所建立的方法能反映ＧＳＴ－πｍＲＮＡ表达的微小差异并能作批量分析，ＧＳＴ－πｍＲＮＡ可作为食管癌的肿瘤基因标志。     

Analytical method for determination of allylic isoprenols in rat tissues by liquid chromatography/tandem mass spectrometry following chemical derivatization with 3-nitrophtalic anhydride

A liquid chromatography-tandem mass spectrometric (LC-MS/MS) method following chemical derivatization with 3-nitrophtalic anhydride was developed for the simultaneous determination of farnesol and geranylgeraniol in rat liver and testis. One analogue compound of the analytes, n-pentadecanol, was used as an internal standard (IS) for both analytes in this method. Rat tissues were disintegrated with 8% KOH ethanol solution, and then farnesol, geranylgeraniol and IS were extracted with a mixture of n-hexane-ethanol (98.5:1.5, v/v) in twice. Farnesol, geranylgeraniol and IS were then converted to 3-nitrophtalic derivatives of each analyte, and extracted with n-hexane. A turbo ion spray interface was used as the ionization source of LC-MS/MS and the analysis was performed in the multiple reaction monitoring (MRM) mode. The calibration curve at the spiked concentrations of 0.15-15 microg/g for both analytes showed good linearity. The method was precise; the relative standard deviations of the method for rat liver were not more than 13.4 and 5.4% for farnesol and geranylgeraniol, respectively, and those for rat testis were not more than 8.4 and 8.6% for farnesol and geranylgeraniol, respectively. The accuracies of the method for both rat liver and testis were good, with the deviations between the nominal concentration and calculated concentration of farnesol and geranylgeraniol typically being within 12.3 and 10.2%, respectively. This method provided reliable concentration levels for farnesol and geranylgeraniol in rat liver and testis.     

Porous graphitic carbon shows promise for the rapid screening partial DPD deficiency in lymphocyte dihydropyrimidine dehydrogenase in Chinese,Indian and Malay in Singapore by using semi-automated HPLC-radioassay

OBJECTIVE: Dihydropyrimidine dehydrogenase (DPD) catalyzes the degradation of thymine, uracil, and the chemotherapeutic drug 5-Fluorouracil. In general reverse-phase high pressure liquid chromatography is the standard method for separating 5-[2-(14)C]Fluorouracil and 5-[2-(14)C]Fluoro-5,6-dihydrouracil. However, the use of 100% aqueous solution (as HPLC mobile phase) may collapse the C-18 bonded phase and result in a retention time shift. The aim of this study is to develop a rapid, reproducible, sensitive method for screening partial DPD deficiency in healthy volunteers. DESIGN AND METHODS: The activity of DPD was measured using 5-[2- (14)C]Fluorouracil (5-[2-(14)C]FUra) followed by separation of substrate and product 5-[2-(14)C]FUraH(2) with a 15 x 4.6 mm I.D., 5 microm particle size (d(p)) porous graphitic carbon (PGC) column (Hypercarb(R)) and HPLC with online detection of the radioactivity. This was standardized using the protein concentration of the cytosol (NanoOrange(R) Protein Quantitation).RESULTS: Complete baseline separation of 5-[2-(14)C]Fluorouracil (5-[2-(14)C]FUra) and 5-[2-(14)C]Fluoro-5,6-dihydrouracil (5-[2-(14)C]FUraH(2)) was achieved using a porous graphitic carbon (PGC) column. The detection limit for 5-[2-(14)C]FUraH(2) was 0.4 pmol.CONCLUSIONS: By using linear gradient separation (0.1% Trifluoroacetic acid [TFA] in water to 100% Methanol) protocols in concert with PGC columns (Hypercarb(R)), we have demonstrated that a PGC column has a distinct advantage over C-18 reverse phase columns in terms of column stability (pH 1-14). This method provides an improvement on the specific assay for DPD enzyme activity. It is rapid, reproducible and sensitive and can be used for routine screening for healthy and cancer patients for partial and profound DPD deficiency before treatment with 5- FUra.