从掺混肥料的发展现状谈其国家标准制定的设想

介绍我国掺混肥料行业发展现状,存在的主要问题,提出制定掺混肥料国家标准的设想。     

G蛋白耦联受体激酶结合蛋白1通过调节细胞外调节激酶1/2的活性促进成骨细胞迁移

目的探索G蛋白耦联受体激酶结合蛋白1(GITI)在成骨细胞迁移中的作用,并分析其机理。方法通过Western blot方法检测GIT1蛋白在鼠的成骨细胞内的表达；用免疫荧光染色方法确定：在血小板衍生生长因子(PDGF)不刺激和刺激的条件下,GIT1和细胞外调节激酶1/2(ERK1/2)在成骨细胞内的位置；用共同免疫沉淀的方法测定GIT1和ERK1/2相互结合,并且用免疫荧光双染的方法确定这两种蛋白相互结合的位置；用包含GIT1-RNA发夹结构的腺病毒感染成骨细胞后,用免疫荧光染色方法确定磷酸化ERK1/2(pERK1/2)在成骨细胞内的位置,用划痕愈合法检测在PDGF刺激下的迁移能力。结果在成骨细胞内,PDGF刺激导致了GIT1和ERK1/2的相互结合,并且这种结合发生在成骨细胞的局部粘附内。包含GIT1-RNA发夹结构的腺病毒明显抑制了pERK1/2招募至成骨细胞局部粘附内以及PDGF所刺激的成骨细胞的迁移。结论在PDGF刺激下,GIT1招募pERK1/2至成骨细胞的局部粘附内,从而促进成骨细胞的迁移。     

4-1BB(CD137)配体在几种肿瘤细胞株上的表达

目的：研究4—1BBL在几种人肿瘤细胞株上的表达。方法：用RT—PCR及法检测肿瘤细胞内4—lBBL mRNA水平的表达；用流式细胞仪检测肿瘤细胞膜表面4—1BBL的表达。结果：4—1BBL在Jurkat细胞株上高表达(98．97％)，在HL-60和K562上表达较低(分别为24．77％和19．23％)，而在HL-29细胞株上基本不表达(2．13％)。结论：4—1BBL在不同肿瘤细胞株表达水平不同。     

Effects of transforming growth factor-β and platelet-derived growth factor on human gingival fibroblasts grown in serum-containing and serum-free medium

Abstract. Both transforming growth factor-β (TGF-ß) and platelet-derived growth factor (PDGF) have been shown to affect cell proliferation in vitro. The hypothesis being tested was that the effects of the 2 cytokines would be modulated by the presence of serum in the medium. Gingival fibroblasts, obtained from periodontally healthy patients, were maintained in primary culture. Dose response experiments were performed for each growth factor in serum-free medium and in medium containing natural or heat-inactivated fetal bovine serum (10% FBS). Changes in cell numbers were quantified by crystal violet staining. The optimal concentrations of the individual factors (10 ng/ml TGF-ßI, 20 ng/ml PDGF-BB) were then used when the 2 factors were tested in various sequences. In serum-free medium or in medium with 10% natural serum, the response to PDGF-BB was dose-dependent up to 40 ng/ml; however, with 10% heat-inactivated serum, the maximal response was seen at 20 ng/ml. The largest increase in cell numbers was produced by the simultaneous exposure to the two cytokines, rather than a sequential presentation. The findings suggest that the 48-h growth response of human gingival fibroblasts to 10 ng/ml TGF-ß1 or 20 ng/ml PDGF-BB in serum-free medium was equivalent to growth obtained in medium containing heat-inactivated 10% FBS without added growth factors.     

Molecular cloning of a ligand for the inducible T cell gene 4-1BB: a member of an emerging family of cytokines with homology to tumor necrosis factor

4-1BB is an inducible T cell antigen that shows sequence homology to members of an emerging family of cytokine receptors, including those for tumor necrosis factor and nerve growth factor. To aid in the analysis of the function of 4-1BB we have utilized a soluble form of the molecule as a probe to identify and clone the gene which encodes its ligand. The ligand for 4-1BB is a type II membrane glycoprotein that has homology to tumor necrosis factor, lymphotoxin, and the ligands for CD40 and CD27, all of which are themselves ligands to receptors in this superfamily. The gene for 4-IBB is on mouse chromosome 4 and maps close to the p80 form of the tumor necrosis factor receptor as well as the gene for CD30. The gene for 4-IBB ligand maps to mouse chromosome 17, but considerably distal to the tumor necrosis factor and lymphotoxin genes. Interaction of 4-1BB with its ligand induces the proliferation of activated thymocytes and splenic T cells, a response which is mimicked on similar cell populations stimulated with an antibody to 4-1BB.     

DR.lyp/lyp bone marrow maintains lymphopenia and promotes diabetes in lyp/lyp but not in +/+ recipient DR.lyp BB rats

Lymphopenia is due to a frameshift mutation in Gimap5 on rat chromosome 4 and is linked to type 1 diabetes in the diabetes prone (DP) BB rat. The hypothesis that bone marrow derived cells confer the lymphopenia phenotype was tested by reciprocal bone marrow transplantation in 40-day-old lethally irradiated diabetes resistant (DR) congenic DR.lyp/lyp (lymphopenia and diabetes) and DR.+/+ (no lymphopenia and no diabetes) rats. In two independent series of transplants, all DR.lyp/lyp rats (n=5 and 4) receiving DR.lyp/lyp bone marrow retained lymphopenia and developed insulitis (5/5 and 4/4) as well as diabetes in some (2/5 and 3/4). Both DR.+/+ and DR.lyp/lyp rats receiving DR.+/+ bone marrow cells as well as DR.+/+ rats receiving DR.lyp/lyp bone marrow cells showed no lymphopenia or diabetes. In accordance with earlier studies in non-congenic BB rats, the DR.+/+ rats receiving DR.lyp/lyp bone marrow cells recapitulated an intermediary phenotype rather than the +/+ or lyp/lyp phenotypes. Our data demonstrate that BBDP rat lymphopenia and diabetes are transferred by bone marrow transplantation to syngeneic DR.lyp/lyp but not DR.+/+ recipients. The intermediary recapitulation of DR.lyp/lyp T cells in recipient DR.+/-/+/- rats suggests that radiation resistant +/-/+/- T cells, the Gimap5 mutation in bone marrow cells, or both may not support the development of lymphopenia.     

Synergistic effect of deoxyspergualin (DSP) and cyclosporin A (CsA) in the prevention of spontaneous autoimmune diabetes in BB rats

Dose-dependent side effects are frequently observed with immunosuppressive drugs of potential relevance for the immunotherapy of insulin-dependent diabetes mellitus (IDDM), such as CsA and DSP. If CsA and DSP acted synergistically in vivo, their combined use would allow using each compound at lower doses than those required when each drug is given in monotherapy. Consequently, dose-dependent side effects could be reduced and the therapeutic activity maintained or even enforced. Toward this end we studied the effects of combined treatment with CsA and DSP on the course of IDDM in the diabetes-prone (DP)-BB rat. The results show that two ‘low’ doses of CsA (2mg/kg) and DSP (1mg/kg) that are clinically ineffective in suppressing IDDM development in BB rats when administered alone under a prolonged prophylactic regimen (30–105 days old), may successfully prevent, but not cure, the disease when given contemporaneously under the same experimental conditions. The combined treatment was well tolerated, and no side effects were noticed. These data suggest that the combined use of CsA and DSP may deserve consideration for its possible application in the prevention/treatment of human IDDM and other autoimmune diseases.     

阻断4-1BB/4-1BBL通路在系统性红斑狼疮患者T淋巴细胞活化中的作用

目的 探讨协同刺激分子4-1BB/4-1BBL在系统性红斑狼疮(systemic lupus erythematosus,SLE)T淋巴细胞活化中的作用机制.方法 应用RT-PCR和Western blot方法检测体外培养20例SLE患者和20例正常对照者T淋巴细胞活化前后及应用抗4-1BB单抗阻断后p38 MAPK和NF-kB表达的变化.结果 SLE患者T淋巴细胞NF-kB mRNA和p38 MAPK mRNA表达及其蛋白水平明显高于正常对照组(P均＜0.01),活化后的表达进一步升高(P均＜0.01).阻断4-1BB/4-1BBL通路后SLE患者T淋巴细胞p38 MAPK mRNA及蛋白水平的表达均明显下降(P均＜0.01),但是NF-kB mRNA及蛋白水平的表达无明显变化(P＞0.05).结论 协同刺激分子4-1BB可能通过p38MAPK信号转导通路促使SLE患者T淋巴细胞的活化与增殖.     

Platelet-derived growth factor (PDGF) BB acts as achemoattractant for human malignant mesotheliomacells via PDGF receptor b - integrin a3b1 interaction

Platelet-derived growth factor BB (PDGF BB) and the PDGF receptor b are expressed on mesotheliomacells, but their biological function has not yet been defined. In the present study we used Boyden chambersfitted with filters coated with the adhesive matrix proteins fibronectin, laminin, collagen type IV or the non-matrixadhesive molecule poly-L-lysine (PLL). Mesothelioma cells migrated towards PDGF BB at concen-trationsranging from 0.78 to 12.5 ng/ml if matrix proteins were present as adhesive substrates. This migrationwas integrin dependent since the same cells failed to migrate if the adhesive interactions necessary for migra-tionwere provided by molecules other than integrins. Migration of mesothelioma cells on fibronectin, lamininor collagen-type IV in response to PDGF BB was inhibited if the cells were pretreated with blocking anti-bodiesto a3b1 integrin. These findings describe for the first time PDGF BB as a chemoattractant for malig-nantmesothelioma cells and that collaboration between PDGF receptor b and integrin a3b1 is necessaryfor the motile response of these cells to PDGF BB.©Kluwer Academic Publishers