BACKGROUND & AIMS: BACKGROUND AND AIMS OF THE STUDY:Bovine and porcine pericardial tissues stabilized by dye-mediated photooxidation have found application as bioprosthetic heart valve material.

METHODS:To help predict clinical performance, a series of tests were performed to assess the biocompatibility and immunologic properties of these materials.

RESULTS AND CONCLUSIONS:Photooxidized bovine or porcine pericardium sterilized with an iodine-based solution were found to be non-cytotoxic, non-hemolytic, and non-mutagenic. Oil or saline extracts of these tissues passed tests for intracutaneous toxicity (irritation), acute systemic toxicity, and subchronic toxicity. Histopathology of 90-day implants of these tissues in the rabbit model demonstrated no significant macroscopic reaction and only slight microscopic response. Using a rabbit model to assess immune response, both bovine and porcine pericardial tissues elicited low levels of antibody. Furthermore, tissue photooxidation or iodine sterilization did not increase the overall level of antibodies. Glutaraldehyde-treated tissue also elicited low antibody levels which were higher than photooxidized tissue-induced levels. Absorption studies indicated that the photooxidation process may generate new epitopes, possibly collagen cross-links. Using the juvenile sheep model to assess in vivo performance, bioprosthetic valves made with photooxidized tissue were implanted and allowed to serve as functional implants for up to two years. Upon explant, the photooxidized pericardial leaflets were found to be non-calcific and partially covered with a layer of host cells. Histological cross-sections stained with von Willebrand's factor confirmed this layer as endothelial cells.

背景与目标： 研究的背景和目的 : 通过染料介导的光氧化作用稳定的牛和猪心包组织已被用作生物人工心脏瓣膜材料。
方法 : 为了帮助预测临床表现，进行了一系列测试以评估这些材料的生物相容性和免疫学特性。
结果和结论 : 发现用碘基溶液灭菌的光氧化牛或猪心包具有非细胞毒性，非溶血性，和非诱变性。这些组织的油或盐水提取物通过了皮内毒性 (刺激)，急性全身毒性和亚慢性毒性的测试。在兔模型中，这些组织的90天植入物的组织病理学没有明显的宏观反应，只有轻微的微观反应。使用兔模型评估免疫反应，牛和猪心包组织均引起低水平的抗体。此外，组织光氧化或碘灭菌不会增加抗体的总体水平。戊二醛处理的组织也引起低抗体水平，该水平高于光氧化组织诱导的水平。吸收研究表明，光氧化过程可能会产生新的表位，可能是胶原蛋白交联。使用幼年绵羊模型评估体内性能，将用光氧化组织制成的生物人工瓣膜植入并作为功能性植入物长达两年。外植体后，发现光氧化的心包小叶是非钙化的，并部分覆盖有一层宿主细胞。用von Willebrand因子染色的组织学横截面证实了该层为内皮细胞。

BACKGROUND & AIMS: :In the last few years fetal magnetic resonance imaging (MRI) has been proposed as a second level technique in the evaluation of fetal brain anomalies. It has been demonstrated that MRI is highly accurate in illustrating the morphologic changes of developing brain and fetal brain abnormalities being a useful procedure when ultrasonography is inconclusive or doubtful. Starting from the 19-20 weeks gestational age (GA), MRI can reliably depict fetal brain anatomy and locating pathology, offering a robust and reliable tool in the assessment of fetal CNS diseases. In this review both in vivo MRI quantitative and qualitative data about fetal cerebellar development are presented and compared with ultrasonography data. Fetal cerebellar development is gradual, steady, and largely comparable to the development of the supratentorial brain. Archicerebellar (flocculo-nodular lobe) and paleocerebellar (vermis) structures develop first, whereas neocerebellum (cerebellar hemispheres) develop slowly and largely after birth.

背景与目标： : 在过去的几年中，胎儿磁共振成像 (MRI) 已被提议作为评估胎儿大脑异常的第二级技术。已经证明，当超声检查不确定或可疑时，MRI在说明发育中的大脑和胎儿大脑异常的形态变化方面非常准确，这是一种有用的方法。从19-20周的胎龄 (GA) 开始，MRI可以可靠地描述胎儿的大脑解剖结构和定位病理，为评估胎儿中枢神经系统疾病提供了可靠可靠的工具。在这篇综述中，介绍了有关胎儿小脑发育的体内MRI定量和定性数据，并将其与超声检查数据进行了比较。胎儿小脑的发育是渐进的，稳定的，并且在很大程度上与幕上大脑的发育相当。小脑 (小脑结节叶) 和古小脑 (ver) 结构首先发育，而新脑 (小脑半球) 在出生后缓慢且大部分发育。

BACKGROUND & AIMS: BACKGROUND:A novel classification of alpha-1 adrenoceptor subtypes (High, Low) was applied to human benign prostatic hypertrophy (BPH) tissue. METHODS:Human BPH specimens were examined by a radioligand binding assay method using 3H-prazosin, and those data were compared with preoperative therapies. RESULTS:(1) Scatchard analysis showed a high-affinity site (Kd:27.18 +/- 6.41 pM; Bmax:9.29 +/- 0.98 fM/mg protein; mean +/- SE) as alpha 1H, and a low-affinity site (Kd: 4088.0 +/- 744.34 pM, Bmax: 140.81 +/- 19.98 fM/mg protein) as alpha 1L subtype, for prazosin. (2) The Kd and Bmax were not different in the nontreated group (n = 5), alpha 1 blocker group (n = 5), and antiandrogen group (n = 5), in either alpha 1-high affinity or alpha 1-low affinity subtype. (3) Phenoxybenzamine had different pKi values for the above two adrenoceptor subtypes. Scatchard analysis showed that alpha 1-high affinity binding site disappeared in the presence of 1 microM of phenoxybenzamine, and the Kd and Bmax values in the presence of 1 microM of phenoxybenzamine were almost identical to the alpha 1-low affinity site of the two subtypes. CONCLUSIONS:Human BPH tissue possesses both alpha 1H- and alpha 1L-adrenoceptor subtypes according to the affinities for prazosin, and only the alpha 1H subtype can be completely inhibited by some concentration of phenoxybenzamine. Treatment by alpha 1 blocker may not change the conditions of alpha 1-adrenoceptors in prostatic tissue.

背景与目标：

BACKGROUND & AIMS: :Plectin is a widely expressed protein that is very large in size and that has all the attributes of a multifunctional crosslinking and organizing element of the cytoskeleton. It displays a multidomain structure, versatile binding activities, and subcellular localizations that enable it to strengthen cells against mechanical stress forces. Moreover, hereditary gene defects in plectin cause epidermolysis bullosa simplex (EBS)-MD, a severe skin blistering disease with muscular dystrophy. Here we report the analysis of the exonintron organization of the rat plectin gene and the identification of several different isoforms on the transcriptional level. We show that of 35 coding exons identified, 4 serve as alternative first exons splicing into the same successive exon 2, which is the first of 7 exons encoding a highly conserved actin-binding domain. RNase protection mapping of transcripts containing 3 of the identified 4 alternate first exons revealed their coexpression in rat glioma C6 cells and in a series of different rat tissues that we examined. Significant variations in expression levels of first exons indicated the possibility of tissue-specific promoter usage. In addition, plectin splice variants lacking exon 31 (> 3 kb), which encodes the entire rod domain of the molecule, were identified in a variety of rat tissues. This study provides first insights into a complex plectin gene regulatory machinery with similarities to that of dystrophin.

背景与目标： : pletin是一种广泛表达的蛋白质，其大小非常大，并且具有细胞骨架的多功能交联和组织元件的所有属性。它显示出多域结构，多种结合活性和亚细胞定位，使其能够增强细胞抵抗机械应力的能力。此外，plectin的遗传性基因缺陷会导致大疱性表皮松解症 (EBS)-MD，这是一种伴有肌营养不良的严重皮肤水疱性疾病。在这里，我们报告了对大鼠plectin基因外显子组织的分析，并在转录水平上鉴定了几种不同的同工型。我们显示，在鉴定出的35个编码外显子中，有4个作为替代的第一个外显子拼接成相同的连续外显子2，这是编码高度保守的肌动蛋白结合域的7个外显子中的第一个。包含鉴定出的4个交替第一外显子中的3个的转录物的RNase保护作图显示了它们在大鼠神经胶质瘤C6细胞和我们检查的一系列不同大鼠组织中的共表达。第一个外显子表达水平的显着变化表明使用组织特异性启动子的可能性。此外，在多种大鼠组织中鉴定出缺少外显子31 (> 3 kb) 的pletin剪接变体，该外显子编码分子的整个杆结构域。这项研究提供了与肌营养不良蛋白相似的复杂pletin基因调控机制的第一个见解。

BACKGROUND & AIMS: OBJECTIVES:This prospective study was designed to assess the sensitivity and specificity of Doppler ultrasound parameters in the diagnosis of cirrhosis and portal hypertension. METHODS:Portal and hepatic arterial Doppler ultrasound was performed on 76 patients with cirrhosis and esophageal varices and on 73 age- and sex-matched controls. The parameters evaluated were portal venous velocity and hepatic arterial pulsatility index. The liver vascular index was calculated as the ratio of portal venous velocity to hepatic arterial pulsatility index. RESULTS:Portal venous velocity was significantly lower (11.0 +/- 2.4 vs 15.9 +/- 2.8 cm/s, p < 0.001) and hepatic arterial pulsatility index was significantly higher (1.28 +/- 0.18 vs 0.95 +/- 0.17,p < 0.001) in patients than in controls. Thus, the liver vascular index was significantly lower in patients than in controls (8.7 +/- 2.1 vs 17.2 +/- 4.3 cm/s, p < 0.001). The sensitivity and specificity of these parameters in the detection of cirrhosis and portal hypertension was then analyzed with the receiver operating characteristic curve. The best cut-off values were considered to be 13 cm/se of portal venous velocity and 1.1 of hepatic arterial pulsatility index, showing a sensitivity and specificity of 83, 85, 84, and 81%, respectively. The best cut-off value of the liver vascular index was 12 cm/s with a sensitivity and specificity of 97 and 93%, respectively. CONCLUSIONS:The liver vascular index is a high sensitive and specific Doppler ultrasound parameter in the diagnosis of cirrhosis and portal hypertension.

背景与目标：

BACKGROUND & AIMS: :The sodium iodide symporter (NIS) mediates iodide (I(-)) transport in the thyroid gland and other tissues and is of increasing importance as a therapeutic target and nuclear imaging reporter. NIS activity in vitro is currently measured with radiotracers and electrophysiological techniques. We report on the development of a novel live cell imaging assay of NIS activity using the I(-)-sensitive and genetically encodable yellow fluorescent protein (YFP) variant YFP-H148Q/I152L. In FRTL-5 thyrocytes stably expressing YFP-H148Q/I152L, I(-) induced a rapid and reversible decrease in cellular fluorescence characterized by 1) high affinity for extracellular I(-) (35 muM), 2) inhibition by the NIS inhibitor perchlorate, 3) extracellular Na(+) dependence, and 4) TSH dependence, suggesting that fluorescence changes are due to I(-) influx via NIS. Individual cells within a population of FRTL-5 cells exhibited a 3.5-fold variation in the rate of NIS-mediated I(-) influx, illustrating the utility of YFP-H148Q/I152L to detect cell-to-cell difference in NIS activity. I(-) also caused a perchlorate-sensitive decrease in YFP-H148Q/I152L fluorescence in COS-7 cells expressing NIS but not in cells lacking NIS. These results demonstrate that YFP-H148Q/I152L is a sensitive biosensor of NIS-mediated I(-) uptake in thyroid cells and in nonthyroidal cells following gene transfer and suggest that fluorescence detection of cellular I(-) may be a useful tool by which to study the pathophysiology and pharmacology of NIS.

背景与目标： : 碘化钠同向转运体 (NIS) 介导碘 (I(-)) 在甲状腺和其他组织中的转运，作为治疗靶标和核成像报告基因的重要性日益提高。目前使用放射性示踪剂和电生理技术测量体外的NIS活性。我们报告了使用I(-) 敏感且可遗传编码的黄色荧光蛋白 (YFP) 变体YFP-H148Q/I152L对NIS活性进行新型活细胞成像测定的开发。在稳定表达YFP-H148Q/I152L的FRTL-5甲状腺细胞中，I(-) 诱导细胞荧光的快速和可逆降低，其特征是1) 对细胞外I(-) (35 muM) 的高亲和力，2) NIS抑制剂高氯酸盐的抑制，3) 细胞外Na(+) 依赖性，和4) TSH依赖性，表明荧光变化是由于I(-) 通过NIS流入所致。FRTL-5细胞群内的单个细胞表现出NIS介导的I(-) 流入速率的3.5倍变化，说明YFP-H148Q/I152L用于检测NIS活性的细胞间差异。I(-) 还导致表达NIS的COS-7细胞中YFP-H148Q/I152L荧光的高氯酸盐敏感降低，但在缺乏NIS的细胞中不引起。这些结果表明，YFP-H148Q/I152L是基因转移后甲状腺细胞和非甲状腺细胞中NIS介导的I(-) 摄取的敏感生物传感器，并表明细胞I(-) 的荧光检测可能是研究的有用工具。NIS的病理生理学和药理学。

BACKGROUND & AIMS: :The strategic use of fluorine substitution in drug discovery and drug development is well documented. The small size and high electronegativity of fluorine are among properties of this element that lend special advantages. Applications in drugs targeted to the central nervous system (CNS) have been particularly fruitful in addition to favorable properties seen in many peripherally acting drugs. Fluorine substitution can be used to solve problems unique to the CNS, such as blood brain barrier (BBB) penetration. Likewise, use of the positron emitting isotope, (18)F, provides a unique tool for non-invasive imaging and diagnoses in the CNS. In this review, fluorine in CNS drugs and drug discovery are discussed.

背景与目标： : 氟替代在药物发现和药物开发中的战略用途已得到充分证明。氟的小尺寸和高电负性是该元素的特殊优点之一。除了在许多外周作用药物中看到的有利特性外，针对中枢神经系统 (CNS) 的药物中的应用特别富有成效。氟替代可用于解决CNS特有的问题，例如血脑屏障 (BBB) 渗透。同样，使用正电子发射同位素 (18)F为CNS中的非侵入性成像和诊断提供了独特的工具。本文对中枢神经系统药物中的氟和药物发现进行了讨论。

BACKGROUND & AIMS: UNLABELLED:A Methodical Study:

AIM OF THE STUDY:To analyse the feasibility of colour and spectral Doppler assessment of blood flow in the fetal right (RPA) and left (LPA) main pulmonary arteries in relation to fetal position and to gestational age.

STUDY DESIGN:The fetal position was a priori divided into 3 types, depending on whether the fetal heart was visualised apically (Type 1), from the right side (Type 2) or from the left side (Type 3). Three groups A (19-25 weeks gestation), B (26-32) and C (33-39) including 33 consecutive pregnancies each, were examined to document the fetal position as well as the rate of the successful Doppler examinations of the RPA and/or LPA.

RESULTS:The fetal position Type 2 was most common throughout gestation (in group A = 42%, B = 36%, C = 51%) followed by the type 3 and then type 1. The rate of successful Doppler records from the RPA and LPA depended on the fetal position: In Type 2 RPA in 98%; in Type 3, LPA in 100%; but the apical approach was not effective (< 40%). Depending on gestational age, the success rates for a Doppler examination of at least one vessel were high (> 85%), whereas successful examination of both vessels was unlikely (12%).

CONCLUSIONS:In the second half of pregnancy, independent of fetal position, Doppler examination of at least one pulmonary artery is successful in most cases, whereas the assessment of both vessels is rather difficult.

背景与目标： 未标记 : 有条不紊的研究:
研究的目的 : 分析彩色和频谱多普勒评估胎儿右 (RPA) 和左 (LPA) 主肺动脉血流与胎儿位置和胎龄的可行性。
研究设计 : 根据胎儿心脏是从右侧 (2型) 还是从左侧 (3型) 可视化，先验地将胎儿位置分为3种类型。A组 (妊娠19-25周)，B组 (26-32) 和C组 (33-39)，每组33次连续怀孕，检查以记录胎儿位置以及RPA和/或LPA的成功多普勒检查率。
结果 : 2型胎儿位置在整个妊娠期间最常见 (A组 = 42%，B = 36%，C = 51%) 接着是类型3，然后是类型1。来自RPA和LPA的成功多普勒记录的速率取决于胎儿位置: 在2型RPA中98%; 在3型中，在100% 中LPA; 但是根尖方法无效 (< 40%)。根据胎龄的不同，对至少一个血管进行多普勒检查的成功率很高 (> 85%)，而对两个血管的成功检查不太可能 (12%)。
结论 : 在怀孕的后半段，在大多数情况下，独立于胎儿位置，对至少一条肺动脉进行多普勒检查是成功的，而对两条血管的评估相当困难。

BACKGROUND & AIMS: PURPOSE:A prospective evaluation of spiral CT angiography (SCTA) as the sole pre-operative imaging modality for abdominal aortic aneurysm repair.

MATERIALS AND METHODS:Spiral CT angiography was compared with conventional transfemoral angiography in 30 patients and results correlated with surgical findings in 22 patients. The following features were assessed: renal artery number and disease; upper and lower aneurysm extent; aneurysm size; perianeurysmal inflammation; iliac artery disease; radiation dose; and contrast usage.

RESULTS:Spiral CT angiography agreed with conventional angiography in all cases of severe stenosis or occlusion of renal arteries and had 90% agreement overall for renal artery disease. Two of nine accessory renal arteries seen at conventional angiography were missed. For showing aneurysm extent SCTA was 100% sensitive, and performed better than conventional angiography. Aneurysm size was better shown with SCTA. In iliac disease SCTA, as performed in this study, was poor for mild-moderate disease, but detected four of six severely stenosed/occluded iliac arteries seen at conventional angiography. Prospective sensitivity for perianeurysmal inflammation was 33%. Radiation dose for SCTA was approximately twice and contrast dose approximately three times that for conventional angiography.

CONCLUSION:Spiral CT angiography can provide all the necessary imaging information to plan aneurysm repair in the non-claudicant.

背景与目标： 目的 : 对螺旋ct血管造影 (SCTA) 作为腹主动脉瘤修复的唯一术前成像方式的前瞻性评估。
材料和方法 : 将30例患者的螺旋ct血管造影与常规经股动脉造影进行了比较，结果与22例患者的手术结果相关。评估了以下特征: 肾动脉数量和疾病; 上，下动脉瘤范围; 动脉瘤大小; 动脉瘤周围炎症; 髂动脉疾病; 辐射剂量; 和造影剂使用。
结果 : 在所有严重肾动脉狭窄或闭塞的病例中，螺旋ct血管造影与常规血管造影一致，并且在肾动脉疾病方面总体上90% 一致。在常规血管造影中观察到的9条副肾动脉中有2条被遗漏。对于显示动脉瘤范围，SCTA 100% 敏感，并且比常规血管造影更好。SCTA能更好地显示动脉瘤大小。在本研究中进行的SCTA在轻度-中度疾病中较差，但在常规血管造影术中发现了六个严重狭窄/闭塞的动脉中的四个。33% 了对动脉瘤周围炎症的前瞻性敏感性。SCTA的辐射剂量约为常规血管造影的两倍，造影剂剂量约为常规血管造影的三倍。
结论 : 螺旋ct血管造影可以提供所有必要的成像信息，以计划非幽闭者的动脉瘤修复。

BACKGROUND & AIMS: PURPOSE:To determine the clinical importance and relative value of reinterpreting brain CT imaging studies by subspecialty experts regarding changes in clinical management. METHODS:Computerized records were queried at two institutions during the years 2002-2003 for both primary interpretation by board-certified nonneuroradiologists and secondary interpretation by three neuroradiologists. A total of 1,081 cases were reviewed. Each case was initially interpreted as an emergent or urgent study. The reinterpreted studies were scored as concordant or discordant by the subspecialty experts. The discordant studies were then categorized as a "major discordance" if there was a change in clinical management, or as a "minor discordance" if there was no impact or change in clinical management. RESULTS:Of the 1,081 studies reviewed, 14 studies were identified as discordant (1.3%). Of those discordant studies, four were categorized as major discrepancies necessitating a change in clinical management (0.4 %). Ten were categorized as minor discrepancies (0.9%). There were no permanent adverse outcomes with respect to morbidity and mortality as a result of any discrepancy. CONCLUSION:The vast majority of interpreted head CT cases read by board-certified general radiologists do not result in discordant interpretations as verified by subspecialty experts. Discordant interpretations did not result in changes in clinical management in most cases. Double reading of head CTs by subspecialty experts appears to be an inefficient method of substantially improving imaging health quality outcomes.

背景与目标：

BACKGROUND & AIMS: STUDY DESIGN:A cross-sectional study of the spine in 40 young adults after solid organ transplantation in childhood. OBJECTIVE:To evaluate the impact of organ transplantation and long-term immunosuppressive treatment on growing spine using magnetic resonance imaging (MRI). SUMMARY OF BACKGROUND DATA:A review of the current literature reveals no systematic evaluation of the spine after transplantation in childhood. METHODS:A total of 40 adult patients (mean age 22.1 years, range, 16.0-27.0), who received either kidney, liver, or heart transplant as children, were evaluated. Mean follow-up after transplantation was 11.2 years (range 3.0-18.0). All patients filled in a questionnaire, underwent an interview and physical examination, as well as had MRI of the spine. Standing spinal radiographs were taken from patients with a rib hump > or = 6 degrees. RESULTS:There were 8 (20%) patients who had a history of vertebral fracture. Eleven (28%) patients reported frequent back pain at rest. There were 15 (38%) patients who had scoliosis > 10 degrees (range 10 degrees -69 degrees ). On MRI, narrowed disc spaces were noted in 32 (80%) patients, and irregular endplates were noted in 24 (60%). There were 14 (35%) patients who had at least 1 compressed or wedged vertebra (> 20%). Patients treated for acute rejection had wedged vertebrae, speckled or black disc spaces, and irregular endplates more often than patients without rejections. Males had wedged vertebrae more often than females (P = 0.0067). CONCLUSIONS:Back pain, scoliosis, wedged vertebrae, and narrowed, degenerated disc spaces are common after solid organ transplantation in childhood.

背景与目标：

BACKGROUND & AIMS: :CD3(-)CD4(+)CD45(+) inducer cells are required for the initiation of mucosa-associated organogenesis of both nasopharynx-associated lymphoid tissues (NALT) and Peyer's patches (PP) in the aerodigestive tract. CXCL13(-/-) mice and mice carrying the paucity of lymph node T cell (plt) mutation and lacking expression of CCL19 and CCL21 accumulate CD3(-)CD4(+)CD45(+) cells at the site of NALT but not of PP genesis. Although NALT was observed to develop in adult CXCL13(-/-) and plt/plt mice, the formation of germinal centers in CXCL13(-/-) mice was affected, and their population of B cells was much lower than in the NALT of CXCL13(+/-) mice. Similarly, fewer T cells were observed in the NALT of plt/plt mice than in control mice. These findings indicate that the initiation of NALT organogenesis is independent of CXCL13, CCL19, and CCL21. However, the expression of these lymphoid chemokines is essential for the maturation of NALT microarchitecture.

背景与目标： : CD3(-)CD4 () CD45 () 诱导细胞是启动鼻咽相关淋巴组织 (NALT) 和Peyer斑块 (PP) 的粘膜相关器官发生所必需的。CXCL13(-/-) 小鼠和携带缺乏淋巴结T细胞 (plt) 突变且缺乏CCL19和CCL21表达的小鼠在NALT位点积累CD3(-)CD4 () CD45 () 细胞，而不是PP发生。尽管在成年CXCL13(-/-) 和plt/plt小鼠中观察到NALT的发展，但CXCL13(-/-) 小鼠的生发中心的形成受到影响，其b细胞种群远低于CXCL13 (/-) 小鼠的NALT。同样，在plt/plt小鼠的NALT中观察到的T细胞少于对照小鼠。这些发现表明，NALT器官发生的启动与CXCL13，CCL19和ccl21无关。然而，这些淋巴趋化因子的表达对于NALT微结构的成熟至关重要。

BACKGROUND & AIMS: Magnetic resonance has assumed a preeminent role in the imaging evaluation of the spine. Owing to its multiplanar capability and superior soft tissue contrast, magnetic resonance imaging is the procedure of choice for a host of spinal disorders including degenerative disc disease, tumor evaluation, trauma, and spinal deformities. It represents the most accurate means of distinguishing between recurrent disc herniation and epidural fibrosis, and it excels at the assessment of many postoperative abnormalities such as infection, adjacent segment disc degeneration, and arachnoiditis. Magnetic resonance imaging is also helpful in the evaluation of numerous diagnostic challenges that are less well resolved by other means. This includes the distinction between disc herniation and epidural hematoma, synovial cyst from nonspecific fibrous thickening of a facet capsule, and the evaluation of numerous other soft tissue abnormalities. Computed tomography, computed tomography myelography, and scintigraphy continue to be useful for numerous specific disorders and in those patients with metal hardware or contraindications to magnetic resonance scanning. Overall, however, magnetic resonance is the imaging procedure preferred for many spinal disorders. This article is the first installment of a 3-part series discussing the role of magnetic resonance imaging of spinal disorders. Section 1 will describe the varying imaging modalities available and their relative advantages and disadvantages. A consideration of magnetic resonance imaging techniques will follow, followed by a discussion of the imaging manifestations of early degenerative disc disease. Section 2 will be devoted to an in depth discussion of specific pathologic processes encountered in patients with degenerative disc disease. Section 3 will end the series with a consideration of postoperative imaging followed by a discussion of spinal deformities, trauma, and neoplasms.

背景与目标： 磁共振在脊柱的成像评估中发挥了重要作用。由于其多平面能力和出色的软组织对比度，磁共振成像是许多脊柱疾病 (包括退行性椎间盘疾病，肿瘤评估，创伤和脊柱畸形) 的首选方法。它代表了区分复发性椎间盘突出症和硬膜外纤维化的最准确方法，并且擅长评估许多术后异常，例如感染，相邻节段椎间盘退变和蛛网膜炎。磁共振成像也有助于评估许多诊断难题，而其他方法无法很好地解决这些难题。这包括椎间盘突出症和硬膜外血肿之间的区别，关节突囊的非特异性纤维增厚引起的滑膜囊肿，以及对许多其他软组织异常的评估。计算机断层扫描，计算机断层扫描脊髓造影和闪烁显像对于许多特定疾病以及那些具有金属硬件或磁共振扫描禁忌症的患者仍然有用。然而，总的来说，磁共振是许多脊柱疾病首选的成像程序。本文是由3部分组成的系列文章的第一部分，讨论了脊柱疾病的磁共振成像的作用。第1节将描述可用的各种成像方式及其相对的优缺点。随后将考虑磁共振成像技术，然后讨论早期退行性椎间盘疾病的成像表现。第2节将致力于深入讨论退行性椎间盘疾病患者遇到的特定病理过程。第3节将在系列结束时考虑术后影像学，然后讨论脊柱畸形，创伤和肿瘤。

BACKGROUND & AIMS: Nodular regenerative hyperplasia (NRH) of the liver is a condition characterized by multiple monoacinar regenerative nodules in the absence of fibrous septa. When these nodules become confluent they may be seen with sonography or CT. The appearance of these pseudotumoral pattern of NRH has been scarcely described with MRI. We present the imaging findings of five patients with NRH and a pseudotumoral form at sonography. Sonography depicted hyperechoic lesions in four patients and hypoechoic lesions in another. Computed tomography showed hypodense lesions with little contrast enhancement in two patients. Three patients showed subtle focal liver lesions on MRIisointense in one, mildly hypointense in another, and minimally hyperintense in a patient with siderosis. The dynamic behavior at MRI was similar to the normal liver parenchyma. Hyperechoic lesions on sonography or hypodense lesions on CT, barely or not seen on MRI, can be indicative of NRH in an appropriate clinical setting.

背景与目标： 肝脏的结节性再生增生 (NRH) 是一种疾病，其特征是在没有纤维间隔的情况下多个单腺泡再生结节。当这些结节汇合时，可以通过超声检查或CT看到它们。MRI几乎没有描述这些NRH假瘤模式的出现。我们在超声检查中介绍了5例NRH和假瘤形式患者的影像学发现。超声检查显示了四名患者的高回声病变，另一名患者的低回声病变。计算机断层扫描显示两名患者的低密度病变几乎没有对比度增强。三名患者在一个mriisointensient上显示出细微的局灶性肝病灶，在另一个患者中显示出轻度低信号，而在患有铁质沉着症的患者中显示出最小高信号。MRI的动态行为与正常肝实质相似。在适当的临床环境中，超声检查中的高回声病变或CT上的低密度病变 (在MRI上几乎看不到或看不到) 可以指示NRH。

BACKGROUND & AIMS: :Isolated rat adipose tissue-derived stromal cells (rATSCs) contain pluripotent cells that can be differentiated into a variety of cell lineages, including neural cells. Recent work has shown that ATSCs can make neurosphere-like clumps and differentiate into neuron-like cells expressing neuronal markers, but their therapeutic effect is unclear. Here we report that intravenous infusion of oligodendrocyte precursor cells (OPCs) derived from rATSC autograft cells sources improve motor function in rat models of spinal cord injury (SCI). After 4-5 weeks, transplanted rATSC-OPC cells survived and migrated into the injured region of SCI very efficiently (30-35%) and migrated cells were partially differentiated into neurons and oligodendrocyte. Also, we found some of the engrafted OPCs migrated and integrated in the kidney, brain, lung, and liver through the intravenous system. Behavioral analysis revealed the locomotor functions of OPC-autografted SCI rats were significantly restored. Efficient migration of intravenously engrafted rATSC-OPCs cells into SCI lesion suggests that SCI-induced chemotaxic factors facilitate migration of rATSC-OPCs. Here, we verified that engrafted rATSCs and SCI-induced chemotaxic factors indeed play an important role in proliferation, migration, and differentiation of endogeneous spinal cord-derived neural progenitor cells in the injured region. In transplantation paradigms, the interaction between engrafted rATSC-OPCs and endogeneous spinal cord-derived neuronal progenitor cells will be important in promoting healing through fate decisions, resulting in coordinated induction of cell migration and differentiation.

背景与目标： : 分离的大鼠脂肪组织来源的基质细胞 (rATSCs) 含有多能细胞，可分化为多种细胞谱系，包括神经细胞。最近的研究表明，ATSCs可以形成神经球状团块并分化为表达神经元标记的神经元样细胞，但其治疗效果尚不清楚。在这里，我们报告了来自rATSC自体移植细胞来源的少突胶质前体细胞 (opc) 的静脉输注改善了大鼠脊髓损伤 (SCI) 模型的运动功能。4-5周后，移植的ratsc-opc细胞存活并非常有效地迁移到SCI的损伤区域 (30-35%)，并且迁移的细胞部分分化为神经元和少突胶质细胞。此外，我们发现一些移植的opc通过静脉系统迁移并整合到肾脏，大脑，肺和肝脏中。行为分析表明，OPC自体移植的SCI大鼠的运动功能显着恢复。静脉移植的ratsc-opcs细胞有效迁移到SCI病变中，表明SCI诱导的趋化因子促进了ratsc-opcs的迁移。在这里，我们证实了移植的大鼠干细胞和SCI诱导的趋化因子确实在受损区域内源性脊髓神经祖细胞的增殖，迁移和分化中起重要作用。在移植范例中，移植的ratsc-opcs与内源性脊髓衍生的神经元祖细胞之间的相互作用对于通过命运决定促进愈合非常重要，从而导致细胞迁移和分化的协调诱导。