转化生长因子β对人颈椎关节突关节软骨细胞基质金属蛋白酶13基因表达的调节作用及意义

目的 探讨转化生长因子β（TGF-β）对人的颈椎关节突关节透明软骨细胞基质金属蛋白酶13（MMP-13）基因表达的作用，旨在阐明颈椎退行性变的相关发生机理。方法 应用逆转录方法PCR及实时荧光定量方法，检测不同浓度TGF-β作用传代培养人的透明软骨细胞MMP-13mRNA的含量。另外3种不同浓度分别与10ng／ml IL-1β组成联合作用组，共计6个实验组及1个正常对照组。结果 正常对照组中透明软骨细胞仅见MMP-13mRNA扩增产物，实验组TGF-β1、10和100ng／ml作用12h后，MMP-13mRNA表达逐渐增强；而联合作用组中，随着TGF-β1浓度的升高，MMP-13mRNA表达逐渐降低，并且各组之间存在明显的差异（P〈0．05）。结论 TGF-β可按剂量依赖方式调节颈椎关节突关节软骨细胞MMP-13mRNA的表达。     

氟伐他汀对环孢素A所致大鼠成纤维细胞肾毒性的保护作用

目的 观察免疫抑制剂环孢素Ａ（CsA）对大鼠肾脏成纤维细胞增殖及细胞因子表达的影响以及氟伐他汀的干预作用，探讨氟伐他汀对CsA肾毒性的保护作用。 方法 体外培养大鼠肾脏成纤维细胞，四甲基偶氮唑盐（MTT）比色法测定CsA及氟伐他汀对细胞增殖的影响。RT-PCR方法检测转化生长因子β1（TGF-β1）、结缔组织生长因子（CTGF）及c-fos mRNA水平。Western印迹检测纤连蛋白(FN)的表达。 结果 CsA可明显抑制成纤维细胞增殖，且呈剂量和时间依赖效应（P < 0.05）。氟伐他汀与CsA合用后，对细胞增殖有明显的抑制作用（P < 0.01）。CsA刺激成纤维细胞TGF-β1、CTGF、c-fos及FN的产生（P < 0.05），氟伐他汀可下调这些改变（P < 0.05）。 结论 氟伐他汀可减轻CsA所致的大鼠肾脏成纤维细胞毒性     

Effects of basic fibroblast growth factor on biological characteristics of osteoblasts

Objective: To elucidate the effects of exogenous basic fibroblast growth factor ( bFGF ) on biological characteristics of rat osteoblasts cultured in vitro. Methods: The osteoblasts isolated from a Sprague-Dawley rat and cultured in vitro were treated with different concentrations of bFGF ( 5-50 ng/ml) respectively. At 24 hours after treatment, the proliferating cell nuclear antigen was measured with immunocytochemistry, alkaline phosphatase (ALP) activity was determined and the expression of transforming growth factor beta 1 ( TGF-β1 )was detected to observe the effects of bFGF on growth and differentiation of osteoblasts. Resu/ts: bFGF ( 5-50 ng/ml ) could obviously promote the growth of osteoblasts. The intracellular expression of TGF-β1 mRNA increased significantly, but the intracellular ALP content decreased. Conclusions: bFGF can obviously stimulate the proliferation of osteoblasts and promote the synthesis of TGF-β1, but cannot promote the differentiation of osteoblasts.     

Inhibition of tissue factor surface expression in human peripheral blood monocytes exposed to cytokines

Interleukin (IL)-4, IL-10, IL-13 and transforming growth factor beta (TGF-β) are known to regulate several monocyte functions, including inhibition of the synthesis of different cytokines. Using quantitative RT-PCR and flow cytometry analysis we investigated the effects of these cytokines on bacterial lipopolysaccharide (LPS)-induced tissue factor (TF) expression in human monocytes. The effects of IL-4 and IL-10 on monocyte chemoattractant protein-1 (MCP-1)- and C-reactive protein (CRP)-induced TF expression were also studied. A direct comparison revealed that IL-4, IL-10 and IL-13 all down-regulated LPS-induced TF expression in a concentration-dependent manner without the need for priming. In contrast, TGF-β required 4 h of priming to inhibit TF expression induced by LPS. IL-10 was the most powerful inhibitor, causing almost complete inhibition at 5 ng/ml. IL-4 and IL-13 exhibited a significantly lower inhibitory capacity even at concentrations of 100 ng/ml. IL-4 and IL-10 showed similar concentration-dependent inhibition of MCP-1- and CRP-induced TF expression. We also showed that the regulatory effect of the interleukins occurred at the mRNA level. In vivo , these inhibitory cytokines may play an important regulatory role in preventing thrombosis. IL-10, in particular, may be a possible candidate as a TF-preventing drug.     

Establishment of a human glioma cell line bearing a homogeneously staining chromosomal region and releasing α- and β-type transforming growth factors

Summary A human glioma cell line (YKG1), which was positively identified for glial fibrillary acidic (GFA) and S-100 proteins, was established from a surgical specimen of a patient with glioblastoma. Chromosome analysis of the cells revealed a homogeneously staining region (HSR) on a marker chromosome. The assay for transforming growth factors (TGFs) in the conditioned medium of the cell line revealed that it contained high levels of - and -type TGFs, which might regulate the growth of glioblastoma and influence on the peritumoral tissues.     

Comparative study of pituitary and bacteria-derived human growth hormone by monoclonal antibodies

We have established hybridoma lines which secrete mouse monoclonal antibodies (Mabs) to human pituitary growth hormone, hGH. Using indirect competitive ELISA and indirect passive hemagglutination inhibition twelve different Mabs were characterized with regard to cross-reactivity with the hGH-related hormones, human chorionic somatomammotropin, hCS, and human prolactin, hPRL. The reactivity of these Mabs with pituitary hGH was compared to that with either bacterially-produced methionyl-hGH or to that of reduced and S-carboxymethylated hGH, which has an altered conformation. None of the Mabs reacted with hPRL. Four did not react with hCS whereas the others showed varying degree of cross-reactivity with hCS. All Mabs reacted more weakly with reduced and S-carboxymethylated hGH than with the native form of the hormone, which was not seen with conventional rabbit antisera to hGH. Thus in the case of hGH the Mabs are superior to conventional antisera in revealing small conformational differences. However the pituitary and bacterially-derived methionyl-hGH were indistinguishable as determined by the 12 Mabs.     

Immunochemical characterization of mouse brain-associated theta (Thy-1) antigen.

The Thy-1 antigens or rat brain and thymus have been isolated and chemically characterized, but those of mice have not been identified. Moreover, it is uncertain whether the antigens are glycolipids or glycoproteins. This study with highly purified preparations of gangliosides GM₁, ¹GD_1a, GD_1b and GT_1b from bovine brain and several ganglioside fractions from mouse brain showed that Thy-1 activity does not reside in gangliosides, but rather in the chloroform-methanol-insoluble residue of brain remaining after extraction of gangliosides. The antigen could be solubilized from this residue with a non-ionic detergent. The antigenic activity of the solubilized preparation was heat-labile but resistant to periodate. The chemical properties of the Thy-1 antigen of mouse brain are discussed.     

Activity of human erythrocyte gangliosides as a receptor to HVJ

Liposomes could bind and fuse efficiently to human erythrocytes in the presence of HVJ when they contained gangliosides isolated from human erythrocytes. Sialosylparagloboside, which has a terminal sequence of NeuAcα2?3Ga1β1?4GlcNac, has a much higher receptor activity to the virus than GD_1a, GD_1b, GT_1b, and GT_1a, all of which contain the terminal sequence of NeuAcα2?3Galβ1?3GalNAc or NeuAcα2?8NeuAcα2?3Galβ1?3GalNAc. The activity of sialosylparagloboside is comparable to that of glycophorin, a major sialoglycoprotein of human erythrocytes, when compared on the basis of the required amount (as sialic acid) of compounds. The high affinity of sialosylparagloboside to the viral HANA protein is also suggested by the finding that it showed high inhibitory activity against HVJ-mediated binding of glycophorin liposomes to erythrocytes. Sialosylparagloboside was also highly susceptible to the viral sialidase, the other biological function of HANA protein.     

Effects of manipulating catecholamines on the incidence of the preovulatory surge of of luteinizing hormone and ovulation in the rat: evidence for a necessary involvement of hypothalamic adrenaline in the normal or 'midnight' surge

The preovulatory surge of luteinizing hormone reaches a maximum at 18.00 h on the day of pro-oestrus in female rats maintained with regular lighting from 06.00 to 20.00 h. This surge is initiated by a discharge of luteinizing hormone-releasing hormone into hypophysial portal blood. In this study, drugs which affect catecholamine-mediated neurotransmission were administered on the day of pro-oestrus and the effects on serum concentrations of luteinizing hormone and on subsequent ovulation were observed. alpha-Methyl-p-tyrosine, diethyldithiocarbamate and SKF 64139 inhibit catecholamine synthesis at the level of tyrosine hydroxylase, dopamine beta-hydroxylase and phenylethanolamine N-methyltransferase, respectively. Although alpha-methyl-p-tyrosine suppressed ovulation, it had a negligible effect on the incidence of the preovulatory surge. In contrast, the various treatments with diethyldithiocarbamate and SKF 64139 resulted in a minimal occurrence of the 18.00 h surge; at relatively low doses, however, these drugs frequently elicited a surge at 22.00 or 24.00 h which invariably resulted in ovulation. The failure of the surge after diethyldithiocarbamate or SKF 64139 was not associated with a loss of pituitary sensitivity to luteinizing hormone-releasing hormone. In terms of the hypothalamic concentration of dopamine, noradrenaline, adrenaline and 5-hydroxytryptamine at 18.00 h on pro-oestrus, the only common effect of diethyldithiocarbamate and SKF 64139, given in a dose which blocks the surge, was a severe depletion of adrenaline; alpha-methyl-p-tyrosine failed to produce this effect despite inducing a marked depression of dopamine and a moderate loss of noradrenaline. Neither the increase in hypothalamic dopamine after diethyldithiocarbamate, nor the alpha 2 receptor blocking properties of SKF 64139 appear to be relevant in this context since injections of L-dopa or piperoxane, an alpha 2 receptor antagonist, were without effect on the surge or ovulation. The failure of the surge after prazosin, an alpha 1 receptor antagonist, indicates that the function of adrenaline may be mediated postsynaptically by alpha 1 receptors. Clonidine, an alpha 2 receptor agonist which reduces the turnover rate of hypothalamic adrenaline, had effects of the surge and ovulation which were comparable to those of diethyldithiocarbamate and SKF 64139, the relatively low doses causing some of the surges to occur at 24.00 instead of 18.00 h and higher doses suppressing the surge at both times and thus preventing ovulation.(ABSTRACT TRUNCATED AT 400 WORDS)