Correction of frequency and phase variations induced by eddy currents in localized spectroscopy with multiple echo times.

As a consequence of the time-varying magnetic field induced by eddy currents, frequency drifting occurs when the sampling window of localized spectroscopy continuously shifts. The frequency drifting and the concomitant phase variations can severely affect spectroscopy results when data are acquired with multiple echo times (TEs), such as in the measurement of glutamate (Glu) concentration using the TE-averaged method. Specifically, the averaged spectra are further broadened and distorted in the presence of residual eddy currents, and editing of the coupled spins of Glu C4 protons is affected, resulting in errors in the measured relative intensity ratio. Postacquisition correction using unsuppressed water as reference can effectively minimize this detrimental effect, as manifested by the significantly enhanced signal intensity. Also, it is demonstrated that the methyl signals of creatine (Cr) at 3.0 ppm and choline (Cho) at 3.2 ppm can be used as internal references in finding frequency and phase disparities between different TEs.     

血管介入仿真模拟器在心血管医生冠状动脉介入技术规范化培训中的作用

目的明确Angiomemor（美国Simbionix公司生产）血管介入仿真模拟器是否有助于冠状动脉造影技术的掌握和提高。方法选取16名无血管放射介入经验的心血管医生，接受相同课时的冠状动脉介入造影理论培训后，按随机表编码随机分为模拟器培训组与非培训组各8名，模拟器培训组8名医生接受Angiomemor血管介入仿真模拟器培训，模拟冠状动脉造影操作，非培训组8名心血管医生未接受仿真模拟器培训。在随后的真实临床环境中操作冠状动脉造影时，评价2组医生冠状动脉造影操作过程中错误的频数、平均造影时间、造影剂使用量及术中放射线剂量。结果相对于非培训组，模拟器培训组医生在冠状动脉造影操作中错误频数减少62．5％、平均造影时间减少44．0％、造影剂使用量减少44．0％，术中平均放射线曝光时间减少了57．7％，平均X线累计曝光剂量减少51．6％，单位面积X线累计曝光剂量减少了52．4％。结论Angiomemor血管介入仿真模拟器有助于医生较快地熟练掌握冠状动脉造影技术，是冠状动脉介入规范化培训的重要辅助手段之一。     

Quisqualate lesions of rat NBM: Selective effects on working memory in a double Y-maze

Some authors have reported that quisqualic acid lesions of the nucleus basalis magnocellularis (NBM), although producing large cortical cholinergic losses, have little effect on memory. The purpose of the present study was to investigate the effects of quisqualic acid lesions of the NBM on working and reference memory in a double Y-maze. Each trial started with placement into one of the two end arms of the first Y-maze, and the correct response was to go down the stem (reference memory). Access was then given to the second Y-maze, the correct response being conditional upon the side of the first Y-maze from which that trial had begun (working memory). Rats were trained to an 88% correct criterion and were then given either bilateral quisqualic acid (60 nM, 0.5 microliters) or sham lesions (0.9% saline, 0.5 microliters) of the NBM. One week postsurgery, rats were tested on the double Y-maze task with delays of 0, 5 or 30 seconds being introduced prior to both the working and reference memory choice. NBM lesions produced a 63.2 +/- 6.2% decrease of cortical choline acetyltransferase (ChAT) compared to unoperated controls. Delays affected only the working memory of the sham group. Rats with lesions showed a significant impairment of working memory at all delays, but no change in reference memory. Results indicate that quisqualic acid lesions of the NBM that produce significant reductions in cortical ChAT selectively impair working memory.     

A flexible, efficient, checkerboard immunoblot system for the detection and semiquantitation of specific antinuclear antibodies.

In this paper an uncomplicated method for the simultaneous detection and semiquantitation of 11 of the 12 commonly studied antinuclear antibodies (ANA) in a single run is described. This new application of checkerboard immunoblotting (CBIB) is based upon available technology and employs purified antigens which can be either purchased or produced in-house. CBIB requires no electronic instrument, can be formatted to meet the needs of the user, is rapidly performed, and has acceptable labor and materials costs. Data on the use of the method to examine available reference antisera is presented. CBIB has also proven practical for the clinical study of 18 sera, at two dilutions per membrane, for each set of specific antinuclear antibodies, also at two or more dilutions.     

猪肾碱性磷酸酶的提纯及性质研究

目的：从猪肾中提取碱性磷酸酶(ALP)，并对其能否作为参考品进行研究。方法：从猪肾皮质中分离刷状缘微绒毛膜，用正丁醇溶解膜结合的酶，经硫酸铵沉淀，DEAE-Sephacel、ConA-Sepharose、Sephadex G-200及抗γ-谷酰基转移酶(GGT)免疫亲和层析提纯ALP。结果：提纯的ALP比活达402kU／g蛋白，几乎不含杂酶(未检出ALT、AST、ChE、AMY、CK、LDH，GGT仅含2U／780U ALP)。其对底物4-硝基磷酸酚(4-NPP)的Km值为1．35mmol／L，最适pH值为10．40。结论：提纯的猪肾ALP与人血清中的ALP酶动力学特性非常相似，为进一步研制ALP参考品奠定了基础。     

Optimization of self-reference thermometry using complex field estimation.

Referenceless, or self-reference, thermometry is a technique for mapping temperature differences in the region of interest (ROI) using the baseline phase estimated by extrapolating the field in the surrounding region for estimation (RFE) and subtracting the estimated baseline from the measured field. In the present work a self-reference technique based on complex field estimation using 2D polynomials comprising complex-valued coefficients was proposed and optimized. Numerical simulations with a Gaussian-profiled phase distribution demonstrated that the ROI radius had to be 2.3-2.5 times the standard deviation (SD) of the Gaussian function in order to keep the error below 8% of the peak phase change. The area ratio between the ROI and the RFE had to be larger than 2.0 to maintain the error level. Based on the simulations, and phantom and volunteer experiments, the complex-based method with independently optimized polynomial orders for the two spatial dimensions was compared with the phase-based method using the similar-order optimization strategy. The complex-based method appeared to be useful when phase unwrapping was not removed. Otherwise, the phase-based method yielded equivalent results with less polynomial orders.     

血中原卟啉一级标准物质的研制及其应用

血中原卟啉（EP）是一项评价铅接触人群健康危险度的生物监测指标，也是筛查缺铁性贫血的敏感和特异性指标。为了保证EP测定的准确度，控制分析误差，在分析中应用血EP的标准物质进行质量控制是很有必要的。根据国家计量局颁布的国家一级标准物质技术规范要求，进行了EP冻干血标准物质的研制工作。收集新鲜牛血，加入EP标准，混匀后分装，冷冻干燥，密封后辐射灭菌，低温避光保存。对样品的均匀性及稳定性进行了检验，结果符合国家一级标准物质的规定。并按照国家一级标准物质的要求，组织了9个实验室，使用灵敏、准确的方法进行定值，取得了准确的特性量值。该标准物质经过国内有关实验室试用，通过专家审查鉴定，已被国家技术监督局批准为国家一级标准物质，样品编号为GBW09136、GBW09137。     

Diet and disadvantage: observations on infant feeding from an inner city

Background: There are few detailed nutritional studies analysing dietary intakes and weaning practices of inner city infants aged 0–12 months. Pasteurized cow's milk (PCM) is not recommended as a main drink until after 1 year of age, although early usage is still common. Premature introduction of pasteurized cow's milk is associated with increased risk of iron deficiency anaemia. Methods: We therefore prospectively examined the dietary effect of early introduction of pasteurized cow's milk on the nutritional intake of 100 infants (mean age at recruitment 7.8 months), whose mothers had already elected to introduce cow's milk before the recommended age of 12 months in a deprived inner city area. In addition, a retrospective questionnaire on feeding practices and food choices was administered and information on parental education and employment was collected, together with a 3-day dietary diary of weighed intakes at recruitment. Results: The results indicate that weaning practices are handed down from family and friends and are intuitive rather than informed. Over 80% of the infants had intakes of iron, zinc and vitamin D below the reference nutrient intake (RNI) and a further 41% had low vitamin C intakes. Prior to introduction of PCM, there was also misuse of infant formula. Twenty per cent added an extra scoop of powder to the feeds, 10% added milk powder to the bottle before addition of water and 30% used microwave ovens to heat the infant bottle. Conclusion: Feeding practices in a deprived inner city area differed substantially from guidelines and infants were at risk of developing nutrient deficiencies as well as poor feeding practices.     

Comparison of the COBAS TaqMan HBV test with the COBAS Amplicor monitor test for measurement of hepatitis B virus DNA in serum

Quantitation of low hepatitis B virus (HBV) DNA levels in patients with chronic hepatitis B is important for monitoring natural history of disease and treatment efficacy. This study aimed to compare the quantitation range and analytical sensitivity of the newly developed COBAS TaqMan HBV test (TaqMan test) with the COBAS Amplicor HBV Monitor Test (Amplicor test), using the Eurohep HBV reference plasma and serum samples from patients. Serial dilutions (2.7x10(1)-2.7x10(8) copies/ml) of the Eurohep HBV reference plasma and 50 serum samples from chronic hepatitis B patients were tested by both assays. The TaqMan test could detect seven (2.7x10(2)-2.7x10(8) copies/ml) of eight dilutions of the reference plasma, while the Amplicor test could only detect three of them (2.7x10(3)-2.7x10(5) copies/ml). The HBV DNA values measured by the TaqMan test correlated very well with the theoretical Eurohep standard values (r=0.998, P<0.001). There were good correlations between the HBV DNA levels measured by the two assays on both the Eurohep reference plasma (r=0.993, P<0.001) and serum samples from patients (r=0.904, P<0.001). Compared to the Amplicor test, the TaqMan test had a higher sensitivity (50 vs. 300 copies/ml), shorter assay time (6 vs. 10 hr), and wider dynamic range (8 vs. 3 logs), and was more cost-effective in a clinical setting. These data indicate that the TaqMan test is an excellent tool for HBV DNA quantitation.