3.0T 3D-TOF MRA对颅内动脉瘤检出率的临床应用研究

目的评价3.0 T时间飞跃法磁共振血管成像(3.0 T 3D-TOF MRA)对颅内动脉瘤的诊断价值。方法选择25例有颅内动脉瘤相关症状患者,其中男性14例,女性11例;年龄25～74岁,平均年龄57岁。对其3.0 T 3D-TOF MRA诊断为颅内动脉瘤患者的磁共振资料进行回顾性分析,并与数字减影血管造影(DSA)对照。结果3.0 T 3D-TOF MRA共显示28个动脉瘤,其中单发22例,3例为多发动脉瘤,起自颈内动脉系统25个;起自基底动脉系统3个;DSA检查共显示27个动脉瘤。结论3.0 T 3D-TOF MRA虽然对于直径≤3 mm的微小动脉瘤的诊断存在一定的误诊及漏诊率,但其诊断颅内动脉瘤时能比较全面地显示动脉瘤,三维信息对临床确立治疗方案有很大帮助。3.0 T 3D-TOF MRA不失为高危人群或临床怀疑颅内动脉瘤患者筛查及随诊观察的有效手段。     

Value of magnetic resonance imaging in predicting efficacy of GnRH analogue treatment for uterine leiomyoma

BACKGROUND: Estimating pharmacological efficacy is important when selecting conservative treatment of uterine leiomyoma. Hence, the ability of magnetic resonance (MR) imaging to predict gonadotrophin-releasing hormone (GnRH) analogue efficacy was investigated. METHODS: A total of 85 lesions was studied in 40 patients who were clinically diagnosed as having uterine leiomyoma and treated with GnRH analogue for 24 weeks. To evaluate changes in lesion size, T2-weighted and gadopentetate-dimeglumine (Gd-DTPA)-enhanced, T1-weighted MR images were obtained within 2 weeks before, and immediately after termination of, GnRH analogue treatment. RESULTS: An average 46.3% size reduction was observed in 45 lesions (52.9%); these were seen as low signal intensity on T2-weighted images and enhanced by Gd-DTPA. Also, an average 44.7% size reduction was observed in lesions enhanced by Gd-DTPA, irrespective of signal intensity findings on T2-weighted images. The average size reduction of unenhanced lesions was only 17.8%, and significantly different from enhanced lesions (P < 0.001). The prediction of efficacy was difficult in those lesions not enhanced. CONCLUSIONS: It is considered that evaluation of MR signal intensities, and the presence or absence of Gd-DTPA enhancement, would predict treatment efficacy before GnRH analogue administration.     

脑动静脉畸形的MRI及MRA诊断

目的 分析脑动静脉畸形（AVM）的MRI有MRA特征，评价MRI及MRA的方法对AVM的诊断价值。方法对49例AVM进行常规MRI及3D－TOF法MRA，应用MOTSA（Multiple overlapping thin slab acquisitiion）和MTC（Magnetization transfer contrast）方法经MKP重建后成像。结果 MRI能显示AVM的确切解剖结构有继发改变，MRA能显示AVM的三维立体结构的全貌。结论 MRI有MRA皆是无创性而有效的方法，MRI结合MRA可对AVM作出全面评价。     

面肌抽搐与三叉神经痛的磁共振诊断价值

目的探讨3D—TOF序列和3DFIESTA序列联合应用对面肌抽搐及三叉神经痛患者血管压迫病因的诊断价值。方法回顾性分析了14例面肌抽搐及三叉神经痛患者磁共振表现。结果14例患者症状侧有神经血管压迫、接触或可疑接触者共有13侧，1侧为听神经瘤压迫。无症状侧只有2侧可疑神经血管接触，12侧无血管接触征象。统计学结果面肌抽搐及三又神经痛患者症状侧与无症状侧比较有显著性差异（P〈0．001）。结论3D TOF MRA和3D FIESTA成像结合不仅可以显示颅内段颅神经血管压迫情况，并可显示局部肿瘤性病变引起的继发性疼痛原因，为临床医师提供术前评估和指导治疗有极其重要的意义。     

3.0T磁共振血管造影普查对颅内动脉开窗畸形的诊断价值

目的通过大样本病例研究颅内动脉开窗畸形磁共振血管造影(MRA)的检出率、好发部位及其临床意义。方法2009年10月至2011年3月行MRA 2 036例患者,确诊动脉开窗畸形25例(开窗畸形组),其中男性14例,女性11例;年龄30~81岁,平均年龄60.5岁。全部行头颅三维时间飞跃MRA(3D-TOF MRA)扫描,将原始图像经工作站处理,得到最大密度投影(MIP)和容积重组(VR)图像,分析颅内动脉开窗畸形的影像学特点,与伴发动脉瘤之间的相关性。结果 2 036例患者中,发现动脉开窗畸形共计25例(检出率1.23%,25/2 036),其中位于基底动脉11例;位于椎动脉颅内段4例;位于前交通动脉区6例;位于大脑中动脉3例;位于大脑后动脉1例。25例开窗畸形中有6例合并动脉瘤,4例位于颈内动脉颅内段,2例位于大脑前动脉。结论 3D-TOF MRA检查能准确诊断、显示颅内动脉开窗畸形。     

Paramagnetic perfluorocarbon-filled albumin-(Gd-DTPA) microbubbles for the induction of focused-ultrasound-induced blood-brain barrier opening and concurrent MR and ultrasound imaging

This paper presents new albumin-shelled Gd-DTPA microbubbles (MBs) that can concurrently serve as a dual-modality contrast agent for ultrasound (US) imaging and magnetic resonance (MR) imaging to assist blood-brain barrier (BBB) opening and detect intracerebral hemorrhage (ICH) during focused ultrasound brain drug delivery. Perfluorocarbon-filled albumin-(Gd-DTPA) MBs were prepared with a mean diameter of 2320 nm and concentration of 2.903×10(9) MBs ml(-1) using albumin-(Gd-DTPA) and by sonication with perfluorocarbon (C(3)F(8)) gas. The albumin-(Gd-DTPA) MBs were then centrifuged and the procedure was repeated until the free Gd(3+) ions were eliminated (which were detected by the xylenol orange sodium salt solution). The albumin-(Gd-DTPA) MBs were also characterized and evaluated both in vitro and in vivo by US and MR imaging. Focused US was used with the albumin-(Gd-DTPA) MBs to induce disruption of the BBB in 18 rats. BBB disruption was confirmed with contrast-enhanced T(1)-weighted turbo-spin-echo sequence MR imaging. Heavy T(2)*-weighted 3D fast low-angle shot sequence MR imaging was used to detect ICH. In vitro US imaging experiments showed that albumin-(Gd-DTPA) MBs can significantly enhance the US contrast in T(1)-, T(2)- and T(2)*-weighted MR images. The r(1) and r(2) relaxivities for Gd-DTPA were 7.69 and 21.35 s(-1)mM(-1), respectively, indicating that the MBs represent a positive contrast agent in T(1)-weighted images. In vivo MR imaging experiments on 18 rats showed that focused US combined with albumin-(Gd-DTPA) MBs can be used to both induce disruption of the BBB and detect ICH. To compare the signal intensity change between pure BBB opening and BBB opening accompanying ICH, albumin-(Gd-DTPA) MB imaging can provide a ratio of 5.14 with significant difference (p = 0.026), whereas Gd-DTPA imaging only provides a ratio of 2.13 and without significant difference (p = 0.108). The results indicate that albumin-(Gd-DTPA) MBs have potential as a US/MR dual-modality contrast agent for BBB opening and differentiating focused-US-induced BBB opening from ICH, and can monitor the focused ultrasound brain drug delivery process.     

A1 segment hypoplasia accompanied by AcomA aneurysms assessed with magnetic resonance angiography

Purpose

This study is to evaluate the use of three-dimensional time-of-flight magnetic resonance angiography (3D-TOF MRA) at 3.0 T for the detection and classification of A1 segment hypoplasia based on a large case series and investigates the potential links with AcomA aneurysm occurrence.

Methods

Between January 2009 and June 2012, 8,013 patients underwent MRA examination at 3.0 T in our hospital. MRA was performed using 3D-TOF with volume rendering technique. The presence and location of A1 segment hypoplasia and AcomA aneurysm was reviewed.

Results

Among the 8,013 patients examined, 138 patients were identified with AcomA aneurysms. 425 patients were defined with A1 segment hypoplasia, among whom 303 right-sided A1 hypoplasia and 122 left-sided A1 hypoplasia. 60 of these 425 patients were confirmed with AcomA aneurysms, among them were 49 right-sided A1 hypoplasia. The prevalence of AcomA aneurysm with A1 segment hypoplasia was 14.1 %, which was much higher compared with that (1.0 %) of AcomA aneurysm without A1 segment hypoplasia (P < 0.001).

Conclusions

The incidence of right-sided A1 segment hypoplasia either accompanied with AcomA aneurysm or not was much greater than that of left-sided. Intracranial AcomA aneurysm development appeared to be associated with A1 segment hypoplasia.     

Analytical quality of assays and comparison of procedures for the sweat test

Sweat test measuring the chloride ion (Cl(-)) concentration in sweat is a tool for the cystic fibrosis (CF) diagnosis. We evaluated analytical criteria of different available methods and compared them into five hospitals and throught a national quality control program. Sweat tests were performed by stimulation using pilocarpine iontophoresis, sweat collection and measurement of sweat Cl(-) (mmol/L) by titration (colorimetric or coulometric end-point) or by in situ direct potentiometry using a chloride-selective electrode. Indirect determination by sweat conductivity measurement was expressed in mmol/L sodium chloride (NaCl) equivalents (Eq). Linearity range was demonstrated for all measurement procedures in the range 10 to 120 mmol/L. Intra-laboratory coefficients of variation (CVs) were <5% for values between 10 and 100 mmol/L. Inter-laboratory CVs were <3% only for conductivity measurement whatever the range. The comparison of results obtained for a same sweat sample, simultaneously by coulometric and conductivity measurements, demonstrated a first degree linear distribution between 30 to 60 mmol/L Cl(-) allowing us to establish an analytical correspondence table for this range. Thus, calculated values for 30, 40 and 60 mmol/L Cl(-) were respectively 57, 66 and 84 mmol/L NaCl Eq. In conclusion, comparison of methods highlighted that the less the sweat test is automatically controlled, the more the operator influence on results quality is important. Our study supports that sweat test result <50 mmol/L NaCl Eq is unlikely with CF diagnosis in absence of clinical arguments.     

First-pass and equilibrium-MRA of the aortoiliac region with a superparamagnetic iron oxide blood pool MR contrast agent (SH U 555 C): results of a human pilot study

The purpose of this study was to study different doses for first-pass and equilibrium phase MRA of aortoiliac vessels with a superparamagnetic iron oxide (SPIO) intravascular MR contrast agent (SH U 555 C) after single i.v. bolus injection. Sixteen healthy volunteers were prospectively enrolled into this single-blind, placebo-controlled clinical trial. SHU 555 C was injected as an i.v. bolus at stepwise increased dose levels of 5, 10, 20 and 40 micromol Fe/kg bodyweight (b.w.) corresponding to injection volumes of 0.01, 0.02, 0.04 and 0.08 ml/kg b.w. Serial high-resolution three-dimensional MRA of the aortoiliac vessels was acquired during first-pass and equilibrium, at 6 min intervals up to 42 min after contrast application using a breath-hold three-dimensional FLASH sequence on a 1.5 T scanner. Intravascular enhancement was calculated within the abdominal aorta and the inferior vena cava and a statistical analysis for significant differences in vessel enhancement was performed during the bolus and equilibrium phases. The visibility of vessels was ranked and effects of potential artifacts on image quality were graded for each time point and dose group. SH U 555 C showed a dose-dependent intravascular enhancement during the observation period (42 min). The highest dose of 40 micromol Fe/kg b.w. revealed the highest image quality during first-pass and equilibrium phases. The intravascular enhancement in the aorta increased dose-dependently from 5 to 40 micromol kg b.w. during first-pass and equilibrium phases (p<0.05). Intravascular signal inhomogeneities were observed at lower doses and decreased with increasing doses. First-pass MRA was diagnostic at doses of 10, 20 and 40 micromol Fe/kg b.w. For equilibrium MRA, a dose of 40 micromol Fe/kg b.w. was considered to be diagnostic. SH U 555 C proved to be a contrast agent with a high T1-effect suitable for both first-pass MRA comparable to gadolinium-enhanced MRA and high resolution equilibrium MRA up to 42 min post-injection (p.i.).     

Magnetic resonance arthrographic dissection of posterolateral corner of the knee: revealing the meniscofibular ligament

Purpose

To evaluate meniscofibular ligament (MFibL) at the posterolateral corner of the knee joint on the magnetic resonance arthrography (MRA) with 70° knee flexion.

Materials and Methods

The MRA of the knee joint was performed at 70° knee flexion. Eighteen patients (19 knee joints) underwent scanning of sagittal, coronal, and axial fat-suppressed T1 weighted images (T1FS), and coronal fat-suppressed T2 weighted images. Sagittal three-dimensional (3D) gradient echo (GRE) images were also obtained. Retrospective review of 19 knee MRA studies was independently performed by two musculoskeletal radiologists. The statistical significance was proved by chi-square test.

Results

The MFibL ligament was optimally demonstrated on the far lateral sagittal 3D GRE and T1FS MRA images. The MFibL appeared as a curvilinear or straight hypointense band of variable thickness, extended from the posterolateral meniscus to upper anteromedial aspect of the fibular head. The MFibL was demonstrated with scale 2 (more than a half length of the ligament) by both reviewers in 73.68% (n=14/19) of the knee 3D GRE images and 89.47% (n=17/19) of the knee T1FS images. The visualization on T1FS and that on GRE were not statistically different from each other (p>0.05). The interobserver agreements were significantly good on both 3D GRE and T1FS images in detecting the ligament (kappa values, 0.642 and 0.683, respectively).

Conclusion

The MFibL is well visualized on the far lateral sagittal MRA at 70° knee flexion, which could potentially be useful in recognizing structures in the posterolateral corner of the knee, including the MFibL.     

褪黑素体内外对胃癌Th1/Th2/Th17型细胞因子表达的影响

目的 探讨褪黑素（MLT）体内外对胃癌Th1/Th2/Th17型细胞因子干扰素（IFN）-γ、肿瘤坏死因子（TNF）、白细胞介素（IL）-2、IL-4、IL-6、IL-10、IL-17a表达的影响。 方法 1.构建荷胃癌小鼠模型,共32只雄性615小鼠全部荷小鼠前胃癌（MFC）细胞后随机分为4组,分别用0、25、50、100 mg/kg剂量褪黑素进行腹腔注射并测量肿瘤长短径。干预1周后取外周血,剥离肿瘤组织进行称重和测量。2.将MFC接种于6孔细胞培养板中,贴壁24 h后分别用0、2、4、6、8、10 mmol/L浓度褪黑素干预,24 h后形态学观察并收集相应上清液。3.采用ELISA检测外周血清中褪黑素的浓度变化。采用流式液相多重蛋白定量技术流式微珠阵列（CBA）分别检测外周血清、细胞上清液中Th1/Th2/Th17型相关细胞因子的浓度变化。 结果 1.成功建立荷胃癌小鼠模型。与阴性对照组相比, 褪黑素中、高剂量组小鼠外周血清褪黑素浓度明显升高,肿瘤体积明显下降。与阴性对照组相比,中剂量组血清中IL-10浓度明显增加;高剂量组血清IFN-γ、IL-2、IL-10浓度均明显增加。2.褪黑素干预MFC细胞实验中,与空白对照组相比,6、10 mmol/L 褪黑素组中IFN-γ浓度显著降低;4、6、8、10 mmol/L 褪黑素组中IL-6浓度明显降低,而 6 mmol/L 褪黑素组IL-10浓度明显升高。以上差异均具有统计学意义（P<0.05）。 结论 褪黑素体内外对胃癌细胞均有抑制作用且可能通过调节Th1/Th2/Th17细胞相关因子IFN-γ、IL-2、IL-6及IL-10的表达起增强肿瘤免疫作用。     

Automatic identification and classification of characteristic kinetic curves of breast lesions on DCE-MRI

Dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) of the breast is being used increasingly in the detection and diagnosis of breast cancer as a complementary modality to mammography and sonography. Although the potential diagnostic value of kinetic curves in DCE-MRI is established, the method for generating kinetic curves is not standardized. The inherent reason that curve identification is needed is that the uptake of contrast agent in a breast lesion is often heterogeneous, especially in malignant lesions. It is accepted that manual region of interest selection in 4D breast magnetic resonance (MR) images to generate the kinetic curve is a time-consuming process and suffers from significant inter- and intraobserver variability. We investigated and developed a fuzzy c-means (FCM) clustering-based technique for automatically identifying characteristic kinetic curves from breast lesions in DCE-MRI of the breast. Dynamic contrast-enhanced MR images were obtained using a T1-weighted 3D spoiled gradient echo sequence with Gd-DTPA dose of 0.2 mmol/kg and temporal resolution of 69 s. FCM clustering was applied to automatically partition the signal-time curves in a segmented 3D breast lesion into a number of classes (i.e., prototypic curves). The prototypic curve with the highest initial enhancement was selected as the representative characteristic kinetic curve (CKC) of the lesion. Four features were then extracted from each characteristic kinetic curve to depict the maximum contrast enhancement, time to peak, uptake rate, and washout rate of the lesion kinetics. The performance of the kinetic features in the task of distinguishing between benign and malignant lesions was assessed by receiver operating characteristic analysis. With a database of 121 breast lesions (77 malignant and 44 benign cases), the classification performance of the FCM-identified CKCs was found to be better than that from the curves obtained by averaging over the entire lesion and similar to kinetic curves generated from regions drawn within the lesion by a radiologist experienced in breast MRI.     

骶前区血管网磁共振成像动态增强扫描不同对比剂剂量成像效果的比较

目的探讨不同剂量对比剂磁共振成像（MRI）动态增强扫描对骶前区血管网三维成像的效果,并评价减少对比剂用量的可行性及临床应用价值。方法选取2012年2月至5月间于本院就诊的40例因盆腔良性病变常规行MRI检查的成年女性患者,数字随机法随机分为两组,A组对比剂剂量为钆浓度0．5mol,L20ml,B组为40ml。采用ACHIEVA3．0TX双源磁共振扫描仪对患者行盆腔e-THRIVE3D等体素动态增强MRI序列扫描,采用最大密度投影（MIP）及容积再现重组（VR）后处理技术进行骶前区血管网重建成像,观察骶前区血管的正常解剖及走行,计算骶正中动脉、骶前区横干静脉显示率和骶正中动脉横径。以骶正中动脉为靶点,分别对两组MIP图像质量采取5分制主观评价方法,通过测定信号强度（SI）、信噪比（SNR）和对比噪声比（CNR）的客观评价指标进行综合比较。结果两组患者图像中骶正中动脉均显示清晰,成功率为100％;骶前区横干静脉的总显示率为72．5％（29／40）,其中A组显示率为75％（15／20）,B组显示率为70％（14／20）,差异无统计学意义。在e-THRIVE序列横断位图像上A组骶正中动脉横径与B组差异无统计学意义[（1．42±0．06）mm比（1．38±0．07）mm,P=0．117]。A组骶正中动脉MIP图像质量主观评价评分略低于B组,但差异无统计学意义[（2．95±0．69）分比（3．10±0．66）分,P=0．479]。A组骶正中动脉MIP图像质量客观评价SI、SNR与B组差异无统计学意义（SI：719．63±124．91比811．66±170．60,SNR：61．71±17．35比74．97±27．91,均P〉0．05）,而CNR低于B组（45．68±13．35比62．41±23．37,P〈0．05）。结论采用体素动态增强成像序列扫描及后处理技术可以清晰显示骶前区血管网。0．5mol/L20ml钆双胺的剂量同样能达到双倍剂量的显像效果,均可显示骶正中动脉及横干静脉的形?     

Computerized interpretation of breast MRI: investigation of enhancement-variance dynamics

The advantages of breast MRI using contrast agent Gd-DTPA in the diagnosis of breast cancer have been well established. The variation of interpretation criteria and absence of interpretation guidelines, however, is a major obstacle for applications of MRI in the routine clinical practice of breast imaging. Our study aims to increase the objectivity and reproducibility of breast MRI interpretation by developing an automated interpretation approach for ultimate use in computer-aided diagnosis. The database in this study contains 121 cases: 77 malignant and 44 benign masses as revealed by biopsy. Images were obtained using a T1-weighted 3D spoiled gradient echo sequence. After the acquisition of the precontrast series, Gd-DTPA contrast agent was injected intravenously by power injection with a dose of 0.2 mmol/kg. Five postcontrast series were then taken with a time interval of 60 s. Each series contained 64 coronal slices with a matrix of 128 x 256 pixels and an in-plane resolution of 1.25 x 1.25 mm2. Slice thickness ranged from 2 to 3 mm depending on breast size. The lesions were delineated by an experienced radiologist as well as independently by computer using an automatic volume-growing algorithm. Fourteen features that were extracted automatically from the lesions could be grouped into three categories based on (I) morphology, (II) enhancement kinetics, and (III) time course of enhancement-variation over the lesion. A stepwise feature selection procedure was employed to select an effective subset of features, which were then combined by linear discriminant analysis (LDA) into a discriminant score, related to the likelihood of malignancy. The classification performances of individual features and the combined discriminant score were evaluated with receiver operating characteristic (ROC) analysis. With the radiologist-delineated lesion contours, stepwise feature selection yielded four features and an Az value of 0.80 for the LDA in leave-one-out cross-validation testing. With the computer-segmented lesion volumes, it yielded six features and an Az value of 0.86 for the LDA in the leave-one-out testing.     

Main anatomical features of the M1 segment of the middle cerebral artery: a 3D time-of-flight magnetic resonance angiography at 3 T study

The purpose of our study was to determine the main anatomical features of the M1 segment of middle cerebral artery (MRA) using a 3D TOF-MRA at 3 T. Reconstructed and post-processed MRA images were independently analysed by two anatomists in order to determine the course patterns, the division patterns and the early cortical branches patterns of the M1 segments. The division patterns were defined as bipode, tripode or other. The ECB were studied according to their number and their distance from the origin of the M1 segment. The interobserver agreement, to determine the division patterns of the M1 segment, was calculated. The division of the M1 segment was bipode in 73% of the MCAs, monopode in 17%, tripode in 9%, and fan-shaped in 1. In 46% of the cases no ECB was found. In the other cases, only 1 ECB was found and it arose from the medium part of the M1 segment. Our results confirm post-mortem microdissection studies and show that strict anatomical criteria may be applied to 3D TOF MRA at 3 T.     

Reference tissue quantification of DCE-MRI data without a contrast agent calibration

The quantification of dynamic contrast-enhanced (DCE) MRI data conventionally requires a conversion from signal intensity to contrast agent concentration by measuring a change in the tissue longitudinal relaxation rate, R(1). In this paper, it is shown that the use of a spoiled gradient-echo acquisition sequence (optimized so that signal intensity scales linearly with contrast agent concentration) in conjunction with a reference tissue-derived vascular input function (VIF), avoids the need for the conversion to Gd-DTPA concentration. This study evaluates how to optimize such sequences and which dynamic time-series parameters are most suitable for this type of analysis. It is shown that signal difference and relative enhancement provide useful alternatives when full contrast agent quantification cannot be achieved, but that pharmacokinetic parameters derived from both contain sources of error (such as those caused by differences between reference tissue and region of interest proton density and native T(1) values). It is shown in a rectal cancer study that these sources of uncertainty are smaller when using signal difference, compared with relative enhancement (15 +/- 4% compared with 33 +/- 4%). Both of these uncertainties are of the order of those associated with the conversion to Gd-DTPA concentration, according to literature estimates.     

椎间隙感染的MRI诊断

目的：分析椎间隙感染的MRI影像特征，评价椎间隙感染的MRI诊断价值。方法：对15例经临床或手术病理证实的椎间隙感染患者行脊柱MRI检查，扫描序列为矢状面FrFsE-T1WI、FrFSE-T2WI、脂肪抑制T2WI，横断面FrFSE-T2WI，其中5例行Gd-DTPA增强对比扫描。结果：15例患者共发现17个椎间隙感染，其中15个发生于腰椎间隙。椎间隙狭窄(13个)，病变椎间盘呈不同程度破坏、碎裂，呈长T1(17个)长T2(15个)信号，T2上椎间盘髓核内正常裂隙状低信号消失(13个)，上下相邻椎体受累破坏(15个)，椎旁软组织肿胀(8个)。5例行Gd-DT-PA增强对比扫描可见病变椎间盘、相邻椎体及椎旁软组织异常强化。结论：MRI对诊断椎间隙感染具有很高的敏感性和准确性，应作为首选的影像学检查方法：     

葡萄糖通过mTORC1信号通路调控成纤维细胞增殖

目的 研究葡萄糖对小鼠皮肤成纤维细胞增殖的影响.方法 将小鼠皮肤成纤维细胞培养在含不同浓度葡萄糖的培养基里,用MTT法检测细胞增殖,7-MGTP pulldown实验检测细胞翻译起始情况,Western blot检测mTORC1信号通路分子的活化.结果 与培养基葡萄糖浓度为5.5 mmol/L相比较,当浓度为15 mmol/L时,促进细胞增殖,与7-MGTP结合的翻译起始复合物增加,mTORC1信号通路活化;当25 mmol/L时,抑制细胞增殖,与7-MGTP结合的翻译始复合物减少,mTORC1信号通路中与细胞增殖相关的4EBP1和与细胞生存相关的Akt的磷酸化减弱.结论 葡萄糖通过对mTORC1信号通路的双向调节作用调控成纤维细胞增殖.     

Humanized antibody to human interleukin-6 receptor inhibits the development of collagen arthritis in cynomolgus monkeys

In the present study, we demonstrated the anti-arthritic effect of humanized anti-human IL-6 receptor (IL-6R) antibody, MRA, in cynomolgus monkey. MRA can react with monkey IL-6R and block signal transduction of IL-6. Collagen-induced arthritis (CIA) was induced by twice immunizing with bovine type II collagen (CII) emulsified with complete adjuvant. MRA was intravenously injected once a week, from the day of the first collagen immunization, for 13 weeks. The symptoms of arthritis were evaluated using a visual scoring system and radiography. Inflammatory parameters (C-reactive protein (CRP), fibrinogen, and erythrocyte sedimentation rate (ESR) and concentrations of anti-CII antibody, anti-MRA antibody, and MRA were monitored regularly. At the end of the study, histological evaluation was carried out. MRA, at a dose of 10 mg/kg, gave rise to statistically significant suppression. The elevation of serum CRP and fibrinogen levels and ESR were also inhibited. Furthermore, radiographic and histological examination showed that MRA treatment suppressed joint destruction. Our results demonstrate that IL-6 plays an important role in monkey CIA and that MRA may be an attractive agent for the treatment of rheumatoid arthritis.     

A multiresolution image based approach for correction of partial volume effects in emission tomography

Partial volume effects (PVEs) are consequences of the limited spatial resolution in emission tomography. They lead to a loss of signal in tissues of size similar to the point spread function and induce activity spillover between regions. Although PVE can be corrected for by using algorithms that provide the correct radioactivity concentration in a series of regions of interest (ROIs), so far little attention has been given to the possibility of creating improved images as a result of PVE correction. Potential advantages of PVE-corrected images include the ability to accurately delineate functional volumes as well as improving tumour-to-background ratio, resulting in an associated improvement in the analysis of response to therapy studies and diagnostic examinations, respectively. The objective of our study was therefore to develop a methodology for PVE correction not only to enable the accurate recuperation of activity concentrations, but also to generate PVE-corrected images. In the multiresolution analysis that we define here, details of a high-resolution image H (MRI or CT) are extracted, transformed and integrated in a low-resolution image L (PET or SPECT). A discrete wavelet transform of both H and L images is performed by using the "à trous" algorithm, which allows the spatial frequencies (details, edges, textures) to be obtained easily at a level of resolution common to H and L. A model is then inferred to build the lacking details of L from the high-frequency details in H. The process was successfully tested on synthetic and simulated data, proving the ability to obtain accurately corrected images. Quantitative PVE correction was found to be comparable with a method considered as a reference but limited to ROI analyses. Visual improvement and quantitative correction were also obtained in two examples of clinical images, the first using a combined PET/CT scanner with a lymphoma patient and the second using a FDG brain PET and corresponding T1-weighted MRI in an epileptic patient.