乙型肝炎患者血清HBV标志物与HBV DNA相关性分析

目的探讨乙型肝炎患者血清学标志(HBVM)与HBV DNA的关系。方法对257例乙型肝炎患者同时检测HBVM与HBV DNA。HBVM检测用EHSA法，HBV DNA检测用PCR法。根据不同检测结果进行对比分析。结果在HBsAg HBeAg HBcAb阳性的血清中HBV DNA阳性率和含量最高，血清HBeAg与HBV DNA含量密切相关，但部分HBeAg阴性或抗-HBe阳性患者也有较高的HBV DNA阳性率及含量。结论PCR定量检测HBV DNA含量更有助于判断体内HBV复制的情况及传染性强弱，在临床上有重要意义。     

Quantification of Acoustic Radiation Force Impulse in Differentiating Between Malignant and Benign Breast Lesions

The aim of this study was to evaluate the use of gray-level quantification (GLQ) in virtual touch tissue imaging (VTI) in the differential diagnosis of breast lesions. GLQ values of 153 lesions (101 benign, 52 malignant) were analyzed with matrix laboratory software (MATLAB, The MathWorks, Natick, MA, USA), with gray levels ranging from 0 (pure black) to 255 (pure white). The diagnostic performance of GLQ was also evaluated using receiver operating characteristic curve analysis. The mean GLQ value for benign lesions (103.27 ± 39.44) differed significantly from that for malignant lesions (44.57 ± 13.61) (p < 0.001). At a cutoff value of 52.31, the sensitivity, specificity, accuracy, positive predictive value and negative predictive value were 86.5%, 93.1%, 90.8%, 86.5% and 93.1%, respectively. In conclusion, we have proposed a method for quantification of gray levels in VTI for the differential diagnosis of breast lesions. Our results indicate that this method has the potential to aid in the classification of benign and malignant breast masses.     

In vivo radiolabel quantification in small-animal models

Current developments in emission tomography especially designed for small-animal imaging are presented. Adaptations of the human tomography principles take advantage of the smaller field of view to achieve about 2-mm usable resolution. Some evaluations in rat tomography are presented, and the problems of limiting resolution of PET and SPECT systems are discussed. Finally, a new approach that more specifically takes into account the parameters induced by in vivo quantification in rodents is presented.     

天津市医德量化考核的研究与实施

天津市卫生局对医德考核量化办法进行了研究,制定了考核标准,建立了考核组织,确定了考核时间与方法,并制定了道德奖惩规定。此项考核办法已付诸实施。     

Calculations and experimental studies of the lineshape of the lactate doublet in PRESS-localized 1H MRS

Accurate quantification of NMR metabolites by spectral modeling requires assumed lineshape functions. For singlet resonances, a combination of Lorentzian and Gaussian lineshapes is sufficient, but for weakly J-coupled resonances such as lactate, more complex lineshapes are necessary. In this work, the lactate lineshape is calculated for the PRESS sequence using standard RF pulses, and compared with experimental measurements. A similar comparison is made for PRESS-localized spectroscopic imaging, in which the lineshape varies from voxel to voxel across the field of view. These observations have important implications for the quantification of lactate in experimental and human studies.     

Quantification of myocardial ischemia and infarction with single photon emission computed tomography

To evaluate the feasibility of ²⁰¹Tl single photon emission computed tomography (SPECT) for quantitative detection of myocardial infarction and ischemia, scintigraphic studies were related to angiographic findings. In study A infarct sizes with SPECT were compared with the angiographic infarct sizes of 30 patients. A linear correlation was found for the % infarct of the left ventricular circumference between both methods (r=0.73; P< 0.001; mean infarct size 20.7%±10.5% (angio) vs 19.8%±12.9% (SPECT), mean±SD). Furthermore, a significant inverse correlation between scintigraphic infarct size and left ventricular ejection fraction (r=-0.87, P< 0.001) was obtained. In study B exercise/rest ²⁰¹Tl SPECT was used for quantification of myocardial ischemia. Forty-three patients underwent both stress ²⁰¹Tl SPECT and biplane exercise left ventriculography. Ischemia was expressed as % defect size of the left ventricular circumference. Sensitivity and specificity for detection of ischemia were 96% and 100% respectively with stress SPECT. Extent of myocardial ischemia correlated significantly with both methods (r=0.63; SPECT defect=1.0 angiographic ischemia +2%; P< 0.001). The regression followed the line of identity and the mean sizes of ischemia were identical (SPECT 12.2±7.6% vs 14.6±12.4% ventriculography, mean±SD) demonstrating the agreement of both methods. However, there was some intraindividual variance between the scintigraphic and the angiographic study. The sensitivity and specificity in single regions with SPECT were lower compared to the global test results. The correlation between the non invasive SPECT and the ventriculography in detection of myocardial infarction and ischemia indicates the clinical value of ²⁰¹Tl SPECT for diagnosis of coronary heart disease.Parts of the results were presented at the 58th sessions of the American Heart Association at Washington, DC (1985)     

Transmission-based scatter correction of 180° myocardial single-photon emission tomographic studies

Meaningful comparison of single-photon emission tomographic (SPET) reconstructions for data acquired over 180° or 360° can only be performed if both attenuation and scatter correction are applied. Convolution subtraction has appeal as a practical method for scatter correction; however, it is limited to data acquired over 360°. A new algorithm is proposed which can be applied equally well to data acquired over 180° or 360°. The method involves estimating scatter based on knowl edge of reconstructed transmission data in combination with a reconstructed estimate of the activity distribution, obtained using attenuation correction with broad beam attenuation coefficients. Processing is implemented for planes of activity parallel to the projection images for which a simplified model for the scatter distribution may be applied, based on the measured attenuation. The appropriate broad beam (effective) attenuation coefficients were determined by considering the scatter buildup equation. It was demonstrated that narrow beam attenuation coefficients should be scaled by 0.75 and 0.65 to provide broad beam attenuation coefficients for technetium-99m and thallium-201 respectively. Using a thorax phantom, quantitative accuracy of the new algorithm was compared with conventional transmission-based convolution subtraction (TDCS) for 360° data. Similar heart to lung contrasts were achieved and correction of 180° data yielded a 10.4% error for cardiac activity compared to 5.2% for TDCS. Contrast for myocardium to ventricular cavity was similarly good for scatter-corrected 180° and 360° data, in contrast to attenuation-corrected data, where contrast was significantly reduced. The new algorithm provides a practical method for correction of scatter applicable to 180° myocardial SPET.     

A novel and rapid method to quantify cytolytic replication of picornaviruses in cell culture

Determining viral titers is a key issue in a wide variety of studies regarding different aspects of virology. The standard methods used for determining picornavirus titers are endpoint titration assay and plaque assay, both time consuming and laborious. The method described uses the tetrazolium salt MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium-bromide) that is reduced to formazane by cellular dehydrogenase, genes shown to be down-regulated during picornavirus infection. The amount formazane produced correlates with the viral titers obtained and can easily be measured using an ELISA plate reader. The colorimetric method has been evaluated using virus types from different genera of the Picornaviridae family. The MTT method reduces the time spent on determining the viral titers and still maintains a reliable accuracy.     

Simultaneous determination of danshensu, ferulic acid, cryptotanshinone and tanshinone IIA in rabbit plasma by HPLC and their pharmacokinetic application in danxiongfang

A selective and sensitive reversed-phase high performance liquid chromatography method was developed and validated for the simultaneous determination of danshensu, ferulic acid, cryptotanshinone, and tanshinone IIA in rabbit plasma using p-hydroxybenzoic acid as internal standard. Liquid–liquid extraction was used for sample preparation. Chromatographic separation was successfully achieved on an Agilent HC-C₁₈ column using a mobile phase composed of methanol–water (from 20:80 to 80:20, v/v) containing 0.5% (v/v) glacial acetic acid. The mobile phase was employing gradient elution at a flow rate of 1.0 ml/min. The method showed good linearity and no endogenous material interfered with the marked compounds and I.S. peaks. The limit of quantification of danshensu, ferulic acid, cryptotanshinone, and tanshinone IIA were 0.1, 0.03, 0.05, and 0.05 μg/ml, respectively. The average extract recoveries of the four compounds from rabbit plasma were all over 60%. The precisions determined from 5 days were all within 10%. The established method has been successfully applied in the pharmacokinetic study and drug interaction of danshensu, ferulic acid, cryptotanshinone, and tanshinone IIA in rabbits after intravenous administration of danxiongfang, a useful compound preparation of traditional Chinese medicine.     

Determination of rifalazil in dog plasma by liquid-liquid extraction and LC-MS/MS: quality assessment by incurred sample analysis

Incurred dog plasma samples were utilized for method quality assessment in this study, where a sensitive LC-MS/MS method was used for determination of the antibacterial agent rifalazil (KRM-1648 or ABI-1648). Reproducibility was estimated by repeated analysis of samples from a pharmacokinetic study, where 23 out of 864 study samples were reassayed during the course of the study. Precision for same-day duplicates was %R.S.D. 3.1 (concentration range 0.7-149 ng/ml), and over the whole study %R.S.D. 11.0 (concentration range 0.5-52 ng/ml). Moreover, standard addition experiments with incurred samples (concentration range 0.30-45 ng/ml) are described, where the recovery of spiked rifalazil amount was measured as a surrogate parameter for accuracy. The mean recovery of the added rifalazil amount was 103% (%R.S.D. 26.2). It was concluded that the described method is robust and reproducible for incurred samples. Liquid-liquid extraction was used for isolation of rifalazil and an isotope labeled internal standard from plasma. A manual procedure, based on an 8 x 12 array format, was used for sample extraction. Extracts were analyzed by reversed-phase liquid chromatography using octylsilica column with gradient elution (1mM ammonium acetate+0.01% (v/v) acetic aid in water and methanol). Mass spectrometric detection was made with positive ion electrospray ionization and LC-MS/MS analysis in a triple-quadrupole mass spectrometer. The lower limit of quantification was 50 pg/ml. MS characteristics of rifalazil are presented. In particular, two different sets of ionization and selected reaction monitoring (SRM) conditions, where in-source fragmentation was used for precursor ion formation in one of the sets, were compared. The good correlation found between the two sets of results for authentic sample extracts indicated that either condition could be used for quantification of rifalazil in dog plasma.