塑料/碘填充剂在CT三维成像和标本铸型中的应用

目的:探求一种既可用于CT三维成像又可用于标本铸型的塑料/碘填充剂(plastic bulking agent mixed with iodine,PBAI)。方法:以0·2、0·5、0·9、1·0、1·2、1·8、2·0、2·5g碘分别溶于10ml乙酸乙酯,再加1·5g聚氯乙烯配成15%塑料填充材料;做成10ml注射器铸件CT扫描,筛选最佳碘浓度灌注材料。选择正常SD大鼠以最佳碘浓度材料行全身血管灌注。MDCT扫描,分别用CT机自带软件和Mimics软件获得大鼠全身血管三维图像,对图像质量进行优良比率评估。结果:最佳碘浓度灌注材料为250g/L。灌注满意大鼠9只,其全身血管三维图像优秀率CT机、Mimics图像分别为88·5%和87·6%;血管铸型优秀率为88·9%。结论:250g/L碘浓度、15%PBAI是一种既可用于CT三维成像,又可用于标本铸型的优良填充剂。     

姜黄素/聚乳酸－乙醇酸共聚物复合薄膜的制备及抗凝血研究

血管支架内再狭窄是血管支架临床应用中最突出的问题,药物洗脱支架的问世成为冠心病介入治疗的一个重要里程碑.但是目前的药物洗脱支架还存在抗凝血不足的问题,药物洗脱支架植入晚期血栓形成的病例在临床上有所报道.姜黄素具有抗增生以及抗凝血等多种药理活性,有望成为药物洗脱支架的新颖药物.我们以可降解高分子材料聚乳酸-乙醇酸共聚物(PLGA)为载体分别制备了三种浓度(3wt%、5wt%、8wt%)的姜黄素复合薄膜.采用傅立叶变换红外光谱研究了复合薄膜的组成成分,结果显示:姜黄素与PLGA的特征峰在复合薄膜的红外图谱中均有出现;体外血小板黏附实验结果显示姜黄素复合薄膜表面的血小板黏附数量减少,较少团聚、变形和激活;复合薄膜的部分凝血活酶时间(APTT)长于纯PLGA薄膜的APTT,这都表明姜黄素/聚乳酸-乙醇酸共聚物复合薄膜的抗凝血性能得到改善,且复合薄膜的抗凝血性能在实验药物浓度范围内随着药物含量的增加,材料的抗凝血性能进一步提高.     

A novel digital tomosynthesis (DTS) reconstruction method using a deformation field map

We developed a novel digital tomosynthesis (DTS) reconstruction method using a deformation field map to optimally estimate volumetric information in DTS images. The deformation field map is solved by using prior information, a deformation model, and new projection data. Patients' previous cone-beam CT (CBCT) or planning CT data are used as the prior information, and the new patient volume to be reconstructed is considered as a deformation of the prior patient volume. The deformation field is solved by minimizing bending energy and maintaining new projection data fidelity using a nonlinear conjugate gradient method. The new patient DTS volume is then obtained by deforming the prior patient CBCT or CT volume according to the solution to the deformation field. This method is novel because it is the first method to combine deformable registration with limited angle image reconstruction. The method was tested in 2D cases using simulated projections of a Shepp-Logan phantom, liver, and head-and-neck patient data. The accuracy of the reconstruction was evaluated by comparing both organ volume and pixel value differences between DTS and CBCT images. In the Shepp-Logan phantom study, the reconstructed pixel signal-to-noise ratio (PSNR) for the 60 degrees DTS image reached 34.3 dB. In the liver patient study, the relative error of the liver volume reconstructed using 60 degrees projections was 3.4%. The reconstructed PSNR for the 60 degrees DTS image reached 23.5 dB. In the head-and-neck patient study, the new method using 60 degrees projections was able to reconstruct the 8.1 degrees rotation of the bony structure with 0.0 degrees error. The reconstructed PSNR for the 60 degrees DTS image reached 24.2 dB. In summary, the new reconstruction method can optimally estimate the volumetric information in DTS images using 60 degrees projections. Preliminary validation of the algorithm showed that it is both technically and clinically feasible for image guidance in radiation therapy.     

Cerebrospinal fluid hepatocyte growth factor level in meningitis

BACKGROUND AND PURPOSE: Hepatocyte growth factor (HGF) is a multifunctional cytokine that has been found to be elevated in tuberculous and bacterial meningitis, but no evaluation has been undertaken of its usefulness in identifying various forms of aseptic meningitis. METHODS: In a retrospective study, the levels of HGF in the cerebrospinal fluid of 65 patients were measured prior to treatment. The association of HGF with non-infectious diseases and clinically or microbiologically proven bacterial, tuberculous, viral, fungal and parasitic meningitis was observed, along with its relation to other parameters of the cerebrospinal fluid. RESULTS: Forty six of the 65 patients (71%) were diagnosed as having meningitis. Cerebospinal fluid HGF level was significantly elevated in patients with meningitis compared with patients with non-infectious diseases (1501 vs 578 pg/mL; Mann-Whitney U test, p=0.001). The highest HGF level was found in bacterial meningitis (2699 pg/mL), followed by tuberculous meningitis (1540 pg/mL), viral meningitis (1431 pg/mL), fungal meningitis (714 pg/mL) and parasitic meningitis (174 pg/mL). There was no association between HGF level and other parameters of the cerebrospinal fluid (Pearson's correlation test). CONCLUSION: Cerebrospinal fluid HGF may offer additional information in the classification of meningitis. This may assist in patient management when no pathogen is cultured from the cerebrospinal fluid and when other parameters of the cerebrospinal fluid demonstrate equivocal results.     

胃癌患者血清CEA、CA19—9及CA72—4联检的临床价值探讨

目的：探讨血清CEA、CA19—9及CA72—4联检在胃癌诊断、病情监测及疗效观察中的价值。方法：采用电化学发光技术检测36例正常对照组、42例良性胃病、55例胃癌患者血清CEA、CA19—9、CA72—4的含量，并对胃癌患者进行治疗前后三种肿瘤标志物的含量变化监测随防。结果：胃癌患者血清CEA、CA19—9、CA72—4的阳性率明显高于正常对照组及良性胃病组，差异有显著性（P〈0．01）。胃癌患者治疗后三种肿瘤标志物含量及阳性率较治疗前有明显下降，差异有显著性（P〈0．01）。三者联检的敏感性、准确性均显著提高（P〈0．01）。结论：血清CEA、CA19-9、CA72—4联检有助于提高胃癌诊断的敏感性、同时对疗效观察及术后监测有重要意义。     

Lack of increase in time to blood culture positivity in a patient with persistent methicillin-resistant Staphylococcus aureus bacteremia predicts failure of antimicrobial therapy

Time to positivity is an available parameter in automated blood culture systems. We report a patient with persistent methicillin-resistant Staphylococcus aureus bacteremia who received various regimens for treatment of methicillin-resistant S. aureus, and demonstrate that monitoring of the time to positive blood culture might be helpful in the early recognition of treatment failure.     

Automatic registration between reference and on-board digital tomosynthesis images for positioning verification

The authors developed a hybrid multiresolution rigid-body registration technique to automatically register reference digital tomosynthesis (DTS) images with on-board DTS images to guide patient positioning in radiation therapy. This hybrid registration technique uses a faster but less accurate static method to achieve an initial registration, followed by a slower but more accurate adaptive method to fine tune the registration. A multiresolution scheme is employed in the registration to further improve the registration accuracy, robustness, and efficiency. Normalized mutual information is selected as the criterion for the similarity measure and the downhill simplex method is used as the search engine. This technique was tested using image data both from an anthropomorphic chest phantom and from eight head-and-neck cancer patients. The effects of the scan angle and the region-of-interest (ROI) size on the registration accuracy and robustness were investigated. The necessity of using the adaptive registration method in the hybrid technique was validated by comparing the results of the static method and the hybrid method. With a 44 degrees scan angle and a large ROI covering the entire DTS volume, the average of the registration capture ranges in single-axis simulations was between -31 and +34 deg for rotations and between -89 and +78 mm for translations in the phantom study, and between -38 and +38 deg for rotations and between -58 and +65 mm for translations in the patient study. Decreasing the DTS scan angle from 44 degrees to 22 degrees mainly degraded the registration accuracy and robustness for the out-of-plane rotations. Decreasing the ROI size from the entire DTS volume to the volume surrounding the spinal cord reduced the capture ranges to between -23 and +18 deg for rotations and between -33 and +43 mm for translations in the phantom study, and between -18 and +25 deg for rotations and between -35 and +39 mm for translations in the patient study. Results also showed that the hybrid registration technique had much larger capture ranges than the static method alone in registering the out-of-plane rotations.     

Separate molecules of West Nile virus methyltransferase can independently catalyze the N7 and 2'-O methylations of viral RNA cap

West Nile virus methyltransferase catalyzes N7 and 2'-O methylations of the viral RNA cap (GpppA-RNA-->m(7)GpppAm-RNA). The two methylation events are independent, as evidenced by efficient N7 methylation of GpppA-RNA-->m(7)GpppA-RNA and GpppAm-RNA-->m(7)GpppAm-RNA, and by the 2'-O methylation of GpppA-RNA-->GpppAm-RNA and m(7)GpppA-RNA-->m(7)GpppAm-RNA. However, the 2'-O methylation activity prefers substrate m(7)GpppA-RNA to GpppA-RNA, thereby determining the dominant methylation pathway as GpppA-RNA-->m(7)GpppA-RNA-->m(7)GpppAm-RNA. Mutant enzymes with different methylation defects can trans complement one another in vitro. Furthermore, sequential treatment of GpppA-RNA with distinct methyltransferase mutants generates fully methylated m(7)GpppAm-RNA, demonstrating that separate molecules of the enzyme can independently catalyze the two cap methylations in vitro.     

骨髓基质细胞移植促进脑缺血大鼠海马巢蛋白的表达

目的:探讨移植骨髓基质细胞(BMSCs)对永久性局灶性脑缺血大鼠海马巢蛋白表达的影响。方法:制备永久性局灶性脑缺血大鼠模型,分为PBS对照组和治疗组,再将每组动物随机均分为脑缺血后7d和14d亚组。PBS对照组在脑缺血后1d注射PBS,治疗组在脑缺血后第1日移植BMSCs。Zausinger六分法检测神经功能恢复情况;免疫组织化学方法检测大鼠海马的巢蛋白表达。结果:在脑缺血后第7日和第14日两个时相点,治疗组的神经功能评分均较高,与PBS对照组之间存在显著性差异;齿状回的颗粒细胞下层、颗粒细胞层和海马锥体细胞层均有巢蛋白表达,在脑缺血后第14日,治疗组的大鼠患侧海马的巢蛋白阳性细胞较对照组表达高,存在显著性差异。结论:BMSCs可以改善脑缺血大鼠的神经功能;促进海马内神经干细胞或反应性星形胶质细胞增殖可能为其修复缺血脑损伤的机制之一。