MAGI3促进E-cadherin翻译修饰并影响β-catenin亚细胞定位

目的：研究MAGI3对细胞黏附连接关键蛋白E-cadherin翻译后修饰及其对β-catenin在细胞内分布的影响,为探讨MAGI3通过调控细胞黏附连接影响肿瘤侵袭、转移的可能机制提供线索。方法首先采用Western印迹方法检测过表达MAGI3后E-cadherin蛋白表达条带的迁移变化,研究其翻译后修饰的变化;然后应用RT-PCR方法检测E-cadherin的表达在mRNA水平的变化,研究MAGI3对其转录水平的影响;进一步利用核质膜分离实验检测MAGI3对β-catenin胞内定位的影响。结果过表达MAGI3使E-cadherin蛋白翻译后修饰发生变化（ P＜0.05）,但在mRNA水平没有明显变化。同时,过表达MAGI3后分布到细胞质膜上的β-catenin明显增多（P＜0.05）。结论 MAGI3可能通过促进E-cadherin的翻译后修饰,并促进β-catenin在细胞膜上的分布。     

自制颅脑CT定位装置在颅内病灶体表定位中的应用

目的：探讨自制颅脑 CT 定位装置在颅内病灶体表定位中的应用价值。方法对65例颅内存在病灶的患者,应用自制颅脑 CT 定位装置行64排螺旋 CT 平扫检查,利用 CT 扫描准直线与定位装置金属线构成的二维平面体表定位颅内病灶。结果65例颅内存在病灶的患者,均能一次性准确体表定位颅内病灶,平均费时3 min。而常规颅内定位方法,按照体表标记物与颅内病灶体表最近点(拟手术切开处)的距离进行统计,前后或上下大多都会偏移1~2 cm。结论利用该颅脑 CT 定位装置,能提高颅内病灶体表定位准确性、效率及减少辐射剂量,使用方便,便于推广。     

Palmatine hydrochloride mediated photodynamic inactivation of breast cancer MCF-7 cells: Effectiveness and mechanism of action

Breast cancer is one of the commonest malignant tumors threatening to women. The present study aims to investigate the effect of photodynamic action of palmatine hydrochloride (PaH), a naturally occurring photosensitizer isolated from traditional Chinese medicine (TCM), on apoptosis of breast cancer cells. Firstly, cellular uptake of PaH in MCF-7 cells was measured and the cytotoxicity of PaH itself on breast cancer MCF-7 cells was estimated using the 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide (MTT) assay. Subcellular localization of PaH in MCF-7 cells was observed using confocal laser scanning microscopy (CLSM). For photodynamic treatment, MCF-7 cells were incubated with PaH and then irradiated by visible light (470 nm) from a LED light source. Photocytotoxicity was investigated 24 h after photodynamic treatment using MTT assay. Cell apoptosis was analyzed 18 h after photodynamic treatment using flow cytometry with Annexin V/PI staining. Nuclear was stained using Hoechst 33342 and observed under a fluorescence microscope. Intracellular production of reactive oxygen species (ROS) was studied by measuring the fluorescence of 2, 7-dichlorofluorescein (DCF) using a flow cytometry. Results showed that PaH treatment alone had no or minimum cytotoxicity to MCF-7 cells after incubation for 24 h in the dark. After incubation for 40 min, the cellular uptake of PaH reached to the maximum, and PaH mainly located in mitochondria and endoplasmic reticulum of MCF-7 cells. Photodynamic treatment of PaH demonstrated a significant photocytotoxicity on MCF-7 cells, induced remarkable cell apoptosis and significantly increased intracellular ROS level. Our findings demonstrated that PaH as a naturally occurring photosensitizer induced cell apoptosis and significantly killed MCF-7 cells.     

Retrograde nuclear import of tRNA precursors is required for modified base biogenesis in yeast

The retrograde movement of tRNAs from the cytoplasm to the nucleus occurs constitutively in eukaryotic cells but its functional significance remains unclear. We show evidence suggesting that in Saccharomyces cerevisiae, a spliced tRNA precursor must be imported into the nucleus before the biogenesis of a modified base can occur. Wybutosine (yW) is a modified base adjacent to the anticodon of tRNA(Phe) and is required for accurate decoding. Glucose starvation or overexpression of the nuclear tRNA binding protein Trz1p both caused nuclear retention of cytoplasmic tRNAs, impaired the yW synthesis, and induced the accumulation of its intermediate, N(1)-methylgunanosine (m(1)G), showing that the postspliced tRNA(Phe) is imported to the nucleus, where m(1)G is formed by Trm5p, after which it is reexported to the cytoplasm, where the yW synthesis is completed by cytoplasmic enzymes.     

Temporal changes in cortical activation during conditioned pain modulation (CPM), a LORETA study

For most healthy subjects, both subjective pain ratings and pain-evoked potentials are attenuated under conditioned pain modulation (CPM; formerly termed diffuse noxious inhibitory controls, or DNIC). Although essentially spinal-bulbar, this inhibition is under cortical control. This is the first study to observe temporal as well as spatial changes in cortical activations under CPM. Specifically, we aimed to investigate the interplay of areas involved in the perception and processing of pain and those involved in controlling descending inhibition. We examined brief consecutive poststimulus time windows of 50 ms using a method of source-localization from pain evoked potentials, sLORETA. This enabled determination of dynamic changes in localized cortical generators evoked by phasic noxious heat stimuli to the left volar forearm in healthy young males, with and without conditioning hot-water pain to the right hand. We found a CPM effect characterized by an initial increased activation in the orbitofrontal cortex (OFC) and amygdala at 250-300 ms poststimulus, which was correlated with the extent of psychophysical pain reduction. This was followed by reduced activations in the primary and secondary somatosensory cortices, supplementary motor area, posterior insula, and anterior cingulate cortex from 400 ms poststimulus. Our findings show that the prefrontal pain-controlling areas of OFC and amygdala increase their activity in parallel with subjective pain reduction under CPM, and that this increased activity occurs prior to reductions in activations of the pain sensory areas. In conclusion, achieving pain inhibition by the CPM process seems to be under control of the OFC and the amygdala.     

Detection and Localization of Peripheral Vascular Bleeding Using Doppler Ultrasound

Background: Hemorrhage from wounds in the extremities is the leading cause of preventable death on the battlefield. To successfully treat these injuries, the exact source of bleeding must be localized. Objective: The purpose of this study was to determine the feasibility of using Doppler ultrasound to precisely detect and localize peripheral vascular bleeding. Methods: Injuries were produced in common femoral arteries (diameter of ∼5 mm) of 28 pigs in vivo. Single puncture injuries were produced using 6 French (F) (n = 10), 9 F (n = 22), and 12 F (n = 12) catheters. In addition, multiple punctures were made (using 6 F and 9 F catheters) in eight common femoral arteries to simulate bleeding from multiple injuries. Finally, laceration injuries were produced using a scalpel in 10 femoral vessels. Results: In color Doppler images, bleeding was observed as a turbulent jet flow originating from the injury site in the vessel. This jet flow had checkered red-blue color pattern at the bleeding site, as opposed to a uniform color pattern in an intact artery. Peak systolic velocity at the injury site, measured using pulsed Doppler, was elevated to up to 152.0 ± 81.6 cm/s, as compared to 78.8 ± 17.5 cm/s in normal arteries. Further, end diastolic velocity increased from 6.1 ± 4.9 cm/s before the injury to up to 59.1 ± 33.1 cm/s after the injury. Resistance index was significantly lower (0.6 for 9 F and 12 F punctures, and 0.8 for 6 F punctures) at the bleeding site in injured arteries as compared to the resistance index of intact arteries (of 0.9). Conclusion: Our results showed a characteristic change in the systolic and diastolic velocities, as well as resistance indices at the injury site in peripheral arteries. These findings may serve as groundwork for development of automated bleeding detection and localization methods, and facilitate various hemorrhage control treatments.     

KNN法在含纤连蛋白域蛋白质亚细胞定位中的应用

目的探讨K最近邻（KNN）法在含纤连蛋白（FN）域蛋白质亚细胞定位中的应用价值。方法选取含FN域蛋白质80个（40个细胞外蛋白质和40个细胞内蛋白质）,采用KNN法进行蛋白质亚细胞定位,并采用jack—knife检验法和5维交叉验证法检验样本的定位的准确率。结果KNN法定位细胞内蛋白36个,细胞外蛋白35个。jackknife法检验KNN法蛋白质定位准确率为88．75％,5维交叉法验证其定位准确率为82．5％。结论利用KNN法可较准确的预测含FN域蛋白质的亚细胞位置。     

骨龄X射线图像的预处理和改进k余弦的指骨关键点定位*

背景：在骨龄自动化评价过程中,二值化阈值的选取直接关系到图像二值化效果以及对指骨关键点的准确定位。 目的：解决骨龄X射线图像二值化阈值选取问题,以及k余弦算法定位指骨关键点速度过慢的弊端,从而达到快速准确定位指骨关键点的目的。 方法：采用图像预处理技术,提出基于OSTU阈值的二次阈值算法,用该方法获取的阈值来二值化骨龄X射线图像;针对k余弦算法定位指骨关键点速度很慢的缺点,提出一种改进的k余弦算法来快速准确的定位指骨关键点。 结果与结论：用改进后的k余弦算法来定位63例指骨关键点的总成功率在95%以上,此法运行速度比k余弦算法快20倍以上,其准确性和速度都达到比较满意的效果。 关键词：指骨关键点;图像预处理技术;阈值算法;骨龄;定位;骨龄评定     

Endorectal MRI after radiation therapy: questioning the sextant analysis

Purpose:

To evaluate whether the information gained by three coregistration systems (sextant, hemi‐prostate, and whole gland) differs significantly, suggesting that one approach should be routinely favored over the others. Despite its known limitations, sextant is the generally accepted standard for magnetic resonance imaging (MRI) and biopsy coregistration; nevertheless, depending on the magnitude of localization errors, other options may be adequate.

Materials and Methods:

Institutional Review Board approval was obtained and the study was Health Insurance Portability and Accountability Act (HIPAA)‐compliant. We identified 70 patients who underwent 1.5 T endorectal MRI of the prostate between 1999 and 2008 after external beam radiotherapy for prostate cancer. A single reader reviewed all T2‐weighted images for the presence or absence of tumor. The performance of each approach was quantified using receiver operating characteristic (ROC) curve analysis. Transrectal ultrasound‐guided sextant biopsies were used as a standard of reference.

Results:

The areas under the ROC curve indicating accuracy for each MRI approach were 0.63 (sextant), 0.68 (hemi‐prostate), and 0.71 (whole gland). There was no statistically significant difference among these approaches.

Conclusion:

As expected, the point estimate was higher for the whole‐gland approach, but not significantly. Reliable assessment of locally recurrent prostate cancer after external beam radiotherapy by endorectal MRI may be made using a sextant, hemi‐prostate, or whole gland approach. The option for one or another approach should not be solely based on estimations of imaging accuracy, but on the purpose of the procedure. J. Magn. Reson. Imaging 2011;33:1086–1090. © 2011 Wiley‐Liss, Inc.     

Improving the interpretability of all-to-all pairwise source connectivity analysis in MEG with nonhomogeneous smoothing

Studying the interaction between brain regions is important to increase our understanding of brain function. Magnetoencephalography (MEG) is well suited to investigate brain connectivity, because it provides measurements of activity of the whole brain at very high temporal resolution. Typically, brain activity is reconstructed from the sensor recordings with an inverse method such as a beamformer, and subsequently a connectivity metric is estimated between predefined reference regions-of-interest (ROIs) and the rest of the source space. Unfortunately, this approach relies on a robust estimate of the relevant reference regions and on a robust estimate of the activity in those reference regions, and is not generally applicable to a wide variety of cognitive paradigms. Here, we investigate the possibility to perform all-to-all pairwise connectivity analysis, thus removing the need to define ROIs. Particularly, we evaluate the effect of nonhomogeneous spatial smoothing of differential connectivity maps. This approach is inspired by the fact that the spatial resolution of source reconstructions is typically spatially nonhomogeneous. We use this property to reduce the spatial noise in the cerebro-cerebral connectivity map, thus improving interpretability. Using extensive data simulations we show a superior detection rate and a substantial reduction in the number of spurious connections. We conclude that nonhomogeneous spatial smoothing of cerebro-cerebral connectivity maps could be an important improvement of the existing analysis tools to study neuronal interactions noninvasively.