人FascDNA的克隆及其在大肠杆菌中表达的研究

为获得高质量及充足的Ｆａｓ蛋白，采用ＰＣＲ技术调整Ｆａｓ基因的开放阅读框架，使之与生物素化蛋白基因阅读框架一致；缺失了ＦａｓｃＤＮＡ基因的起始密码子并增加一个大肠杆菌偏性终止密码子，构建ＦａｓｃＤＮＡ和生物素化融合原核表达质粒ＰｉｎＰｏｉｎｔ－Ｆａｓ。将重组质粒转入大肠杆菌ＨＢ１０１，经５００ｍｍｏｌＩＰＴＧ在３７℃条件下诱导４ｈ，ＳＤＳ－ＰＡＧＥ及Ｗｅｓｔｅｒｎ印迹检测融合蛋白在大肠杆菌得以高效表达，表达量为细菌总蛋白的１３．８％。用亲和层析树脂对生物素化融合蛋白进行亲和层析纯化，得到Ｆａｓ重组的蛋白，且表达的Ｆａｓ融合蛋白具有抗体结合活性。此蛋白的表达成功将解决Ｆａｓ膜蛋白不易提取的难题，为深入研究Ｆａｓ提供了良好材料来源     

中医虚实辨证客观化研究之一——ZF-Ib型腹诊仪的研制

本文介绍ZF-Ib型腹诊仪的设计原理.该仪器能对腹壁的张力或软硬度(即腹力),做准确的量化测定,并根据腹力的五个等级标准(分别为:软、偏软、中等、偏实、实)作出客观判断,为中医临床虚实辨证提供客观依据.     

超声波介导的基因输送技术

近年来超声波介导的基因输送技术由于其相对安全性和操作上的简单得到关注。本文对超声波导致的声致穿孔的机制,空化核的作用——增强基因输送的效率,以及细胞和在体基因输送效率作了综述,讨论了超声波介导的基因输送效率的影响因素。此方法充满希望并且载药的空泡可以作为一种新型药物载体在超声作用下实现药物的靶向输送     

Hyperglycemia potentiates H(2)O(2) production in adipocytes and enhances insulin signal transduction: potential role for oxidative inhibition of thiol-sensitive protein-tyrosine phosphatases

Insulin signal transduction in adipocytes is accompanied by a burst of cellular hydrogen peroxide (H(2)O(2)) that facilitates insulin signaling by inhibiting thiol-dependent protein-tyrosine phosphatases (PTPs) that are negative regulators of insulin action. As hyperglycemia is associated with increased cellular reactive oxygen species, we postulated that high glucose conditions might potentiate the H(2)O(2) generated by insulin and modulate insulin-stimulated protein phosphorylation. Basal H(2)O(2) generation was increased threefold in differentiated 3T3-L1 adipocytes by growth in 25 mM glucose versus 5 mM glucose. High glucose increased the sensitivity of the insulin-stimulated H(2)O(2) signal to lower concentrations of insulin. Basal endogenous total PTP activity and the activity of PTP1B, a PTP implicated in the negative regulation of insulin signaling, were reduced in high glucose conditions, and their further reduction by insulin stimulation was more enhanced in high versus low glucose medium. Phosphorylation of the insulin receptor, IRS-1, and Akt in response to insulin was also significantly enhanced in high glucose conditions, especially at submaximal insulin concentrations. In primary rat adipocytes, high glucose increased insulin-stimulated H(2)O(2) production and potentiated the oxidative inhibition of total PTP and PTP1B activity; however, insulin signaling was not enhanced in the primary cells in high glucose apparently due to cross-regulation of insulin-stimulated protein phosphorylation by activation of protein kinase C (PKC). These studies indicate that high glucose can enhance insulin stimulated H(2)O(2) generation and augment oxidative PTP inhibition in cultured and primary adipocytes, but the overall balance of insulin signal transduction is determined by additional signal effects in high glucose, including the activation of PKC.     

CLONING AND EXPRESSION OF cDNA FOR HUMAN LYMPHO-TOXIN

人淋巴毒素（ｈＬＴ）系由淋巴细胞经抗原或有丝分裂原活化后产生的一类细胞因子，它具有抗瘤、抗病毒活性和许多重要的免疫调节作用，是一种非常有前途的生物制剂。近年来发现的膜相关型淋巴毒素更提示ｈＬＴ可能具有尚未被揭示的免疫调节活性。因此，克隆人ＬＴｃＤＮＡ并在大肠杆菌表达重组ｈＬＴ，对于ｈＬＴ的开发利用和研究其功能都具有重要意义。本实验按照公布的ｈＬＴｃＤＮＡ序列，经计算机分析并结合实验要求设计并合成一对ＰＣＲ引物，采用ＲＴ－ＰＣＲ技术从ＰＨＡ／ＰＭＡ活化２４ｈ的人Ｔ细胞系Ｊｕｒｋａｔ细胞总ＲＮＡ扩增出一５４１ｂｐＤＮＡ片段；经α－互补筛选，质粒小量快速抽提，限制性内切酶酶切鉴定，将该片段定向克隆于ｐＵＣ１８、ｐＵＣ１９质粒载体。限制性内切酶图谱分析和Ｓａｎｇｅｒ双脱氧链终止法序列测定表明：该ＤＮＡ片段与公布的人淋巴毒素ｃＤＮＡ序列完全一致。它包括编码人淋巴毒素成熟肽的全部ｃＤＮＡ序列。再进一步将该ｃＤＮＡ片段克隆于原核表达载体ｐＢＶ２２０，经地高辛标记探针菌落原位杂交筛选，限制性内切酶酶切鉴定方向，筛选出一阳性重组子ｐＢＶ－ｈＬＴ。ＳＤＳ－ＰＡＧＥ和Ｗｅｓｔｅｒｎｂｌｏｔｉｎｇ分析表明：经温控诱导，该重组菌成功     

不同患者手术前后血中IL-2/sIL-2R系统的动态变化

本文研究28例胆囊炎胆石症、结肠癌和直肠癌患者手术前后血中IL-2/sIL-2R系统的动态变化。分别于手术前或当晨,术后1、2～3、5～7d抽血,测定血中IL-2、sIL-2R量,同时作CRP试验。结果表明,施行中等手术胆囊摘除总胆管切开引流术和半结肠切除术对IL-2/sIL-2R系统的影响与患者术前的水平有关。原先异常程度或轻或重,术后影响亦或轻或重,但均未见统计学差异。3例直肠癌患者施行miles氏手术,术后出现明显IL-2量下降,sIL-2R量增高,持续时间长。因此,初步说明创伤大的手术在一定程度上影响机体的IL-2/sIL-2R系统。并可从中发现规律,采取措施,具有一定的临床价值。     

血清、腹水中AFP、CEA及CA125水平对良、恶性腹水的诊断价值

目的 :探讨检测血清、腹水AFP、CEA及CA1 2 5对良、恶性腹水的诊断价值。方法 :放射免疫分析 86例患者血清和腹水AFP、CEA及CA1 2 5的含量。结果 :恶性腹水组血清、腹水AFP、CEA及CA1 2 5水平较之良性腹水组差异非常显著 (p <0 0 1 )。在鉴别结核、肝硬化腹水和恶性腹水时 ,以CA1 2 5≥ 5 0 0U/ml、AFP≥ 30 0ng/ml为临界值[1 ] ,可提高诊断的特异性和准确性。结论 :血清和腹水中AFP、CEA及CA1 2 5水平具有鉴别良、恶性腹水的重要意义。     

Expression of HIF-1 and ubiquitin in conventional renal cell carcinoma: relationship to mutations of the von Hippel-Lindau tumor suppressor gene

Conventional clear cell renal cell carcinomas (cRCC) have mutations of the von Hippel-Lindau (VHL) tumor suppressor gene at 3p25 in approximately 50% of cases. The VHL gene normally regulates ubiquitin-mediated proteolysis of hypoxia-inducible factor 1alpha (HIF-1alpha); in cell lines, VHL inactivation blocks HIF-1alpha proteolysis, resulting in increased HIF-1 expression. This study was undertaken to investigate the relationship between VHL mutations and the expression of ubiquitin and HIF-1alpha in cRCC. Eleven cRCC were studied with microsatellite analysis for 3p deletions and with sequencing for VHL mutations. Immunohistochemistry was performed for HIF-1alpha and ubiquitin. Deletions at 3p25 were found in 10 tumors, and VHL mutations were identified in 6 of these cases. There was staining for ubiquitin and HIF-1alpha in all tumors with VHL mutations. Among the five cases without VHL mutations, staining for ubiquitin or HIF-1alpha was not present in three cases but was present in two tumors, both of which had 3p deletions. The findings support a role for VHL mutations promoting cRCC development by an impairment of HIF-1alpha proteolysis. The findings also suggest that a 3p tumor suppressor gene other than VHL may also influence HIF-1alpha degradation and that there is an additional tumorigenic pathway for cRCC that does not involve VHL or HIF-1.     

ASK1 associates with troponin T and induces troponin T phosphorylation and contractile dysfunction in cardiomyocytes

There is increasing support for the idea that excessive production of proinflammatory mediators such as tumor necrosis factor (TNF) and reactive oxygen species (ROS) contribute to the pathogenesis of cardiac dysfunction. However, the mechanisms by which cytokine/ROS production mediates cardiac dysfunction have not been established. Given that apoptosis signal-regulating kinase 1 (ASK1) is highly expressed in cardiac muscle and that ASK1 is an important mediator in the signaling pathways induced by tumor necrosis factor, interleukin-1, and ROS, we used the yeast two-hybrid system with ASK1 as bait to identify ASK1 substrates from a human heart cDNA library. The cDNA encoding the cardiac troponin T (cTnT) was isolated. ASK1 specifically interacted with cTnT, but not cTnI, in vitro and in vivo via the C-terminal ASK1 domain. ASK1 specifically phosphorylated cTnT in vitro and in vivo. Mutations in cTnT (T194/S198) at an ASK1-phosphorylation consensus sequence significantly reduced phosphorylation by ASK1. ROS-induced ASK1 activation, cTnT phosphorylation, and contractile dysfunction in cardiomyocytes showed similar kinetics. Moreover, overexpression of constitutively active ASK1 induces cTnT phosphorylation and inhibits shortening and calcium transient in adult cardiomyocytes. We conclude that ASK1 plays an important role in regulation of cardiac contractile function by phosphorylating cTnT and may participate in cytokine/ROS-induced pathogenesis of cardiomyopathy and heart failure.