Region-specific growth properties and trophic requirements of brain- and spinal cord-derived rat embryonic neural precursor cells

To determine whether neural precursor cells have region-specific growth properties, we compared the proliferation, mitogenicity, and differentiation of these cells isolated from the embryonic day 16 rat forebrain and spinal cord. Neural precursor cells isolated from both regions were cultured in growth medium supplemented with epidermal growth factor, basic fibroblast growth factor, or epidermal growth factor+basic fibroblast growth factor. Under all three conditions, both neural precursor cell populations proliferated for multiple passages. While spinal cord-derived neural precursor cells proliferated moderately faster in epidermal growth factor-enriched growth medium, brain-derived cells proliferated much faster in basic fibroblast growth factor-enriched growth medium. When exposed to both epidermal growth factor and basic fibroblast growth factor, the two neural precursor cell populations expanded and proliferated more rapidly than when exposed to a single factor, with brain-derived neural precursor cells expanding significantly faster than spinal cord-derived ones (P<0.0001). Differentiation studies showed that both neural precursor cell populations were multi-potent giving rise to neurons, astrocytes, and oligodendrocytes. However, neuronal differentiation from brain-derived neural precursor cells was greater than spinal cord-derived ones (11.95+/-5.00% vs 1.92+/-1.13%; passage 2). Further, the two neural precursor cell populations differentiated into a similar percentage of oligodendrocytes (brain: 8.66+/-5.85%; spinal cord: 7.69+/-3.91%; passage 2). Immunofluorescence and Western blot studies showed that neural precursor cells derived from both regions expressed receptors for basic fibroblast growth factor and epidermal growth factor. However, brain-derived neural precursor cells expressed higher levels of the two receptors than spinal cord-derived ones in growth medium containing epidermal growth factor+basic fibroblast growth factor. Thus, our results showed that neural precursor cells isolated from the two regions of the CNS have distinct properties and growth requirements. Identifying phenotypic differences between these neural precursor cell populations and their growth requirements should provide new insights into the development of cell therapies for region-specific neurological degenerative diseases.     

Effects of x-ray and CT image enhancements on the robustness and accuracy of a rigid 3D/2D image registration

A rigid body three-dimensional/two-dimensional (3D/2D) registration method has been implemented using mutual information, gradient ascent, and 3D texturemap-based digitally reconstructed radiographs. Nine combinations of commonly used x-ray and computed tomography (CT) image enhancement methods, including window leveling, histogram equalization, and adaptive histogram equalization, were examined to assess their effects on accuracy and robustness of the registration method. From a set of experiments using an anthropomorphic chest phantom, we were able to draw several conclusions. First, the CT and x-ray preprocessing combination with the widest attraction range was the one that linearly stretched the histograms onto the entire display range on both CT and x-ray images. The average attraction ranges of this combination were 71.3 mm and 61.3 deg in the translation and rotation dimensions, respectively, and the average errors were 0.12 deg and 0.47 mm. Second, the combination of the CT image with tissue and bone information and the x-ray images with adaptive histogram equalization also showed subvoxel accuracy, especially the best in the translation dimensions. However, its attraction ranges were the smallest among the examined combinations (on average 36 mm and 19 deg). Last the bone-only information on the CT image did not show convergency property to the correct registration.     

Genetic imbalances in pleomorphic xanthoastrocytoma detected by comparative genomic hybridization and literature review.

Pleomorphic xanthoastrocytoma (PXA) is a rare, low-grade astrocytic tumor found in the central nervous system. Histologically, the tumor is characterized by markedly pleomorphic and lipidized cells. Although most of the patients have a favorable prognosis, a small number of cases undergoing recurrence or progression to anaplastic astrocytoma were reported. Very few genetic studies have been performed on PXA because of its rarity and the pathogenesis of this neoplasm is largely unknown. In order to provide an overview of genetic alterations in PXA, we performed comparative genomic hybridization to identify chromosomal imbalances (DNA gains and losses) in three cases of PXA. Genetic imbalance was detected on at least one chromosome for each case. One case, which revealed multiple genetic alterations, showed a poor prognosis. DNA gain on chromosome 7 and loss on 8p were demonstrated in two of three cases, suggesting that the candidate gene(s) located on these regions may play a role in the development of PXA. Further studies are needed to identify the residing candidate genes that are involved in the tumorigenesis of PXA. In addition, the histopathological features and previous genetic studies on PXA are reviewed.     

多脏器恶性肿瘤术后肝黏膜相关淋巴组织淋巴瘤

目的 探讨肝黏膜相关淋巴组织淋巴瘤的临床病理特征。方法 对1例罕见多脏器恶性肿瘤术后肝黏膜相关淋巴瘤病例结合文献进行临床、病理和免疫组化分析。结果 患者于8年和3年前先后发生胃恶性间质瘤、阴囊阴茎皮肤湿疹样癌，有长期化疗史。肿瘤组织学以单核样B细胞为主，并有淋巴滤泡和淋巴上皮病变形成。免疫表型示瘤细胞CD45、CD79α、CD20阳性，CD5、CD10、ALK、TdT阴性，bcl—2、Ki—67少数肿瘤细胞阳性。结论 肝黏膜相关淋巴瘤可以发生于多脏器恶性肿瘤术后，其发病可能与长期使用免疫抑制剂有关，诊断本病时需与肝继发性淋巴瘤及肝的炎性假瘤鉴别。     

汉族人群载脂蛋白CII基因二核苷酸串联重复序列(TG)n(AG)m及(AG)m多态性

采用套式聚合酶链反应结合变性聚丙烯酰胺凝胶电泳和银染技术，并构建载脂蛋白CII（ApoCII)基因二核苷酸串联重复序列（TG）n(AG)m及（AG）m序列等位基因梯阶标准；检测正常汉族人群基因型和等位基因频率分布，检出36种（TG）n(AG)m序列基因型、12种等位基因。等位基因为17、18、26－35，其频率分别为0．061、0．011、0．002、0．002、0．054、0．255、0．372、0．084、0．026、0．039、0．052、0．041。检出7种（AG）m序列基因型、4种等位基因。等位基因为6、7、8、9，其频率分别为0．002、0．152、0．812、0．034。与欧洲白种人比较，ApoCII基因二核苷酸串联重复序列（TG）n(AG)m及（AG）m序列等位基因频率分布均具有明显的种族差异性（P＜0．01，P＜0．01）。     

维生素A阻抑大鼠实验性肝纤维化的病理研究

利用光镜、电镜、免疫组化和形态学定量技术动态研究维生素A对大鼠四氯化碳肝纤维化的抑制作用。结果表明,维生素A可减少四氯化碳中毒大鼠肝内纤维连接蛋白和Ⅰ、Ⅲ型胶原沉积,抑制贮脂细胞向成纤维细胞转化,并可明显地减轻肝纤维化程度。本文还对维生素A抑制肝纤维化的机理及意义作了初步探讨。     

To die or not to die for neurons in ischemia,traumatic brain injury and epilepsy: a review on the stress-activated signaling pathways and apoptotic pathways

After a severe episode of ischemia, traumatic brain injury (TBI) or epilepsy, it is typical to find necrotic cell death within the injury core. In addition, a substantial number of neurons in regions surrounding the injury core have been observed to die via the programmed cell death (PCD) pathways due to secondary effects derived from the various types of insults. Apart from the cell loss in the injury core, cell death in regions surrounding the injury core may also contribute to significant losses in neurological functions. In fact, it is the injured neurons in these regions around the injury core that treatments are targeting to preserve. In this review, we present our cumulated understanding of stress-activated signaling pathways and apoptotic pathways in the research areas of ischemic injury, TBI and epilepsy and that gathered from concerted research efforts in oncology and other diseases. However, it is obvious that our understanding of these pathways in the context of acute brain injury is at its infancy stage and merits further investigation. Hopefully, this added research effort will provide a more detailed knowledge from which better therapeutic strategies can be developed to treat these acute brain injuries.     

High density of immobilized galactose ligand enhances hepatocyte attachment and function

Galactosylated surface is an attractive substrate for hepatocyte culture because of the specific interaction between the galactose ligand and the asialoglycoprotein receptor on hepatocytes. In this study, we described a scheme to achieve high density of immobilized galactose ligands on polyethylene terephthalate (PET) surface by first surface-grafting polyacrylic acid on plasma-pretreated PET film under UV irradiation, followed by conjugation of a galactose derivative (1-O-(6'-aminohexyl)-D-galactopyranoside) to the grafted polyacrylic acid chains. A high galactose density of 513 nmol/cm(2) on the PET surface was used in this study to investigate the behavior of cultured hepatocyte. This engineered substrate showed high affinity to fluorescein isothiocyanate-lectin binding. Primary rat hepatocytes, when seeded at a density of 2 x 10(5) cells/cm(2), attached to the galactosylated PET substrate at a similar efficiency compared with collagen-coated substrate. The hepatocytes spontaneously formed aggregates 1 day after cell seeding and showed better maintenance of albumin secretion and urea synthesis functions than those cultured on collagen-coated surface.     

小儿肝的年龄解剖学研究

分六个年龄组观察了180个(男98,女82)小儿肝的形态、度量、位置及体表投影.小儿肝相对较大,右叶大于左叶,下界位置较低并逐渐上移.在右锁骨中线的肋弓下一般均可触到.小儿肝重随其年龄(身高)的增长而增长,其增长速度相对较慢,尤以Ⅶ组小儿更明显.