沙利度胺抑制TGF-β1诱导的HELF细胞中结缔组织生长因子基因启动子的激活*

 目的： 探讨沙利度胺（thalidomide, THD）对转化生长因子β1（transforming growth factor β1,TGF-β1）诱导的人胚肺成纤维细胞（human embryonic lung fibroblast, HELF）结缔组织生长因子（connective tissue growth factor, CTGF）基因启动子激活的影响。方法: 构建含有人类CTGF基因启动子的报告基因载体pGL3-CTGFP,将其瞬时转染HELF细胞,通过检测萤光素酶的活性,观察TGF-β1和THD对CTGF基因启动子活性的影响。结果: TGF-β1能以剂量依赖方式和时间依赖方式显著增加HELF细胞中报告基因的活性（P<0.05）,最佳剌激浓度是5 μg/L,萤光素酶相对活性为对照组的2.16倍,最佳剌激时间为12 h,萤光素酶相对活性为对照组的2.52倍;THD对报告基因的基础活性无明显影响（P>0.05）,但以剂量依赖方式显著抑制TGF-β1上调报告基因活性的效应(P<0.05)。结论: TGF-β1能以剂量依赖方式和时间依赖方式上调HELF细胞中CTGF基因启动子的活性,而THD能以剂量依赖方式抑制此过程。     

超声诊断早期胚胎停育

目的探讨彩色多普勒超声在早期胚胎停育中的诊断价值。方法应用经腹及经阴道彩色多谱勒超声对首次超声确诊及可疑胚胎停育二次超声确诊病例的超声表现进行分析总结。结果超声一次确诊者60例（80％）,二次确诊者15例（20％）,其中枯萎孕卵33例（45％）,均未见卵黄囊显示;胚胎死亡21例（28%）,其中卵黄囊枯萎17例（23%）,增大4例（5．3％）。结论经腹及经阴道彩色多普勒超声能对胚胎停育及早、快速、准确地进行明确诊断,能早期发现宫内胚胎发育异常,可指导临床及时处理,具有重要的临床应用价值。     

蛋白磷酸酶2A催化亚基下调参与人tau蛋白所致线粒体分裂融合和功能失衡

目的 探讨蛋白磷酸酶 2A 催化亚基(PP2Ac)下调是否参与人tau蛋白积聚引起的线粒体分裂融合动态及功能失衡的机制。方法 大鼠原代海马神经元转染mito-dsRed质粒和人tau40质粒48 h后,共聚焦显微镜观测线粒体分布,免疫印迹检测线粒体分裂融合蛋白、PP2Ac 及PP2A 调节亚基 b(PP2Ab)表达水平;大鼠原代海马神经元和野生型 HEK293 细胞(293wt)共转染siPP2Ac-EGFP质粒和mito-dsRed质粒48 h后,检测线粒体形态和分布;293wt细胞共转染siPP2Ac质粒和mito-Dendra2质粒40 h后,实时观测线粒体分裂融合动态;293wt 细胞沉默 PP2Ac表达后,检测线粒体分裂融合蛋白水平及细胞膜电位和细胞活力;稳定表达人tau的HEK293细胞(293htau)共转染PP2Ac-EGFP质粒和mito-dsRed质粒48 h后,分析线粒体分布和形态及功能。结果 大鼠原代海马神经元表达人 tau 蛋白引起突起线粒体分布下降并伴有PP2Ac水平显著下降(t=4.814, P=0.0086)。下调PP2Ac表达引起大鼠原代海马神经元和HEK293细胞线粒体变长并异常分布于细胞核周围;引起293wt细胞线粒体融合明显加速(t=2.857, P=0.0074);使293wt细胞融合蛋白线粒体融合蛋白(MFN)1(t=6.768, P=0.0025)、MFN2(t=3.121, P=0.0035)和视神经萎缩蛋白1水平显著升高(t=3.775, P=0.0199),动力样蛋白1和Fis1水平不变;使HEK293细胞线粒体相对膜电位(t=2.300, P=0.0270)和细胞活力(t=6.249, P<0.0001)显著降低。上调PP2Ac表达可减轻293htau细胞线粒体形态和分布及功能异常。结论 PP2Ac表达下调参与了人tau蛋白引起的大鼠原代海马神经元和HEK293细胞线粒体形态分布异常及细胞活力下降。     

The benefits and risks of stem cell technology

The potential impact of stem cell technology on medical and dental practice is vast. Stem cell research will not only provide the foundation for future therapies, but also reveal unique insights into basic disease mechanisms. Therefore, an understanding of stem cell technology will be necessary for clinicians in the future. Herein, we give a basic overview of stem cell biology and therapeutics for the practicing clinician.     

Cryptorchidism and endocrine disrupting chemicals

Prospective clinical studies have suggested that the rate of congenital cryptorchidism has increased since the 1950s. It has been hypothesized that this may be related to environmental factors. Testicular descent occurs in two phases controlled by Leydig cell-derived hormones insulin-like peptide 3 (INSL3) and testosterone. Disorders in fetal androgen production/action or suppression of Insl3 are mechanisms causing cryptorchidism in rodents. In humans, prenatal exposure to potent estrogen diethylstilbestrol (DES) has been associated with increased risk of cryptorchidism. In addition, epidemiological studies have suggested that exposure to pesticides may also be associated with cryptorchidism. Some case-control studies analyzing environmental chemical levels in maternal breast milk samples have reported associations between cryptorchidism and chemical levels. Furthermore, it has been suggested that exposure levels of some chemicals may be associated with infant reproductive hormone levels.     

复方牛胎肝提取物联合阿德福韦酯治疗慢性乙型肝炎疗效观察

目的观察复方牛胎肝提取物片联合阿德福韦酯片治疗慢性乙型肝炎患者对肝纤维化的临床疗效。方法将42例慢性乙型肝炎患者随机分为治疗组21例,给予口服复方牛胎肝提取物片及阿德福韦酯片和对照组21例,给予口服阿德福韦酯片,疗程均为48周。观察两组患者在治疗前及治疗48周后两次肝穿刺活检病理学变化和血清透明质酸（HA）的变化。结果治疗后治疗组肝组织炎症活动度2例加重,10例无明显变化,9例减轻,对照组肝组织炎症活动度6例加重,12例无明显变化,3例减轻。治疗组肝脏炎症活动度改善优于对照组,差异有显著性（P=0.029）;治疗组纤维化程度2例加重,10例无明显变化,9例减轻,对照组纤维化程度9例加重,9例无明显变化,3例减轻。治疗组纤维化程度改善明显优于对照组,差异有显著性（P=0.006）;治疗组治疗后HA下降明显（P〈0.001）,对照组未见降低,两组间差异有显著性（P〈0.001）。结论复方牛胎肝提取物片联合阿德福韦酯片能显著地改善肝脏炎症活动度和纤维化程度,优于单用阿德福韦酯治疗。     

Oligodendrogenesis from neural stem cells: Perspectives for remyelinating strategies

Mobilization of remyelinating cells spontaneously occurs in the adult brain. These cellular resources are specially active after demyelinating episodes in early phases of multiple sclerosis (MS). Indeed, oligodendrocyte precursor cells (OPCs) actively proliferate, migrate to and repopulate the lesioned areas. Ultimately, efficient remyelination is accomplished when new oligodendrocytes reinvest nude neuronal axons, restoring the normal properties of impulse conduction. As the disease progresses this fundamental process fails. Multiple causes seem to contribute to such transient decline, including the failure of OPCs to differentiate and enwrap the vulnerable neuronal axons. Regenerative medicine for MS has been mainly centered on the recruitment of endogenous self-repair mechanisms, or on transplantation approaches. The latter commonly involves grafting of neural precursor cells (NPCs) or neural stem cells (NSCs), with myelinogenic potential, in the injured areas. Both strategies require further understanding of the biology of oligodendrocyte differentiation and remyelination. Indeed, the success of transplantation largely depends on the pre-commitment of transplanted NPCs or NSCs into oligodendroglial cell type, while the endogenous differentiation of OPCs needs to be boosted in chronic stages of the disease. Thus, much effort has been focused on finding molecular targets that drive oligodendrocytes commitment and development. The present review explores several aspects of remyelination that must be considered in the design of a cell-based therapy for MS, and explores more deeply the challenge of fostering oligodendrogenesis. In this regard, we discuss herein a tool developed in our research group useful to search novel oligodendrogenic factors and to study oligodendrocyte differentiation in a time- and cost-saving manner.     

The role of metabolism in the developmental toxicity of polycyclic aromatic hydrocarbon-containing extracts of petroleum substances

In vitro assays presently used for prenatal developmental toxicity (PDT) testing only assess the embryotoxic potential of parent substances and not that of potentially embryotoxic metabolites. Here we combined a biotransformation system, using hamster liver microsomes, with the ES-D3 cell differentiation assay of the embryonic stem cell test (EST) to compare the in vitro PDT potency of two 5-ring polycyclic aromatic hydrocarbons (PAHs), benzo[a]pyrene (BaP) and dibenz[a,h]anthracene (DBA), and dimethyl sulfoxide extracts from five PAH-containing petroleum substances (PS) and a gas-to-liquid base oil (GTLb), with and without bioactivation. In the absence of bioactivation, DBA, but not BaP, inhibited the differentiation of ES-D3 cells into beating cardiomyocytes in a concentration-dependent manner. Upon bioactivation, BaP induced in vitro PDT, while its major metabolite 3-hydroxybenzo[a]pyrene was shown to be active in the EST as well. This means BaP needs biotransformation to exert its embryotoxic effects. GTLb extracts tested negative in the EST, with and without bioactivation. The PS-induced PDT in the EST was not substantially changed following bioactivation, implying that metabolism may not play a crucial role for the PS extracts under study to exert the in vitro PDT effects. Altogether, these results indicate that although some PAH require bioactivation to induce PDT, some do not and this latter appears to hold for the (majority of) the PS constituents responsible for the in vitro PDT of these complex substances.