Fractal system — A time domain approach

A method to analyze the fractal system in the time domain is presented so that the dynamic behavior of the system can be studied. The fractal system is represented by a set of linear time-varying differential equations whose order depends on the order of the system under non-fractal condition. Four different types of fractal system are considered and their solutions in the time domain are presented. These analyses show that the fractal system is dynamically more stable with smooth changes of magnitude and less oscillatory than the non-fractal system. Examples of the physiological system of the conduction pathways in the heart and also the polarization phenomena of noble metal are presented to illustrate the phonomena.     

缺氧与复氧对培养的肺动脉内皮细胞功能的影响

缺氧与复氧均可引起肺血管收缩和损伤，本研究观察肺血管内皮细胞活力和血管紧张素转换酶（ＡＣＥ）释放在其中的作用。培养的新生小牛肺动脉内皮细胞（ＰＡＥＣ）在缺氧条件下（０％Ｏ２－９５％Ｎ２）培养６～２４ｈ，其上清液ＡＣＥ活性无显著变化，而细胞活力于缺氧１２～２４ｈ显著增加（与常氧组相比增加２０％～３３％，Ｐ＜０．０５）。ＰＡＥＣ在缺氧条件下培养２４ｈ，复氧培养３～６ｈ后其上清液ＡＣＥ活性显著增加（与常氧组和缺氧组相比Ｐ＜０．０１），于１２ｈ恢复至复氧前的水平。细胞活力的变化与ＡＣＥ的变化类似，复氧３～６ｈ显著高于常氧水平（Ｐ＜０．０１与常氧组相比），１２ｈ恢复至正常。上述结果表明ＰＡＥＣ的ＡＣＥ和细胞活力的变化可能对肺动脉壁本身ＲＡＳ功能的调节及缺氧性肺血管收缩的发生起一定作用。     

Coexpression of growth arrest-specific gene 6 and receptor tyrosine kinases,Axl and Sky,in human uterine endometrium and ovarian endometriosis

We demonstrated the expression of Gas6, the protein product of the growth arrest-specific gene 6 (gas6) and a member of the vitamin K-dependent protein family, and its receptor tyrosine kinases, Axl and Sky, in human uterine and ovarian endometriotic endometria using RT-PCR-Southern blot analysis and immunohistochemistry. Gas6, Axl and Sky mRNA were detected in all samples analysed. There was no significant difference between the levels of Sky mRNA in normal uterine and endometriotic endometria; however, the levels of Gas6 and Axl mRNA in endometriotic endometria were significantly higher than in normal endometria. These mRNA levels showed no significant alteration during the menstrual cycle. In the immunohistochemical study, Gas6, Axl and Sky were found in endometrial glandular cells and stromal cells in all samples analysed. This study demonstrates the coexpression of receptor tyrosine kinases and their ligand, Gas6, in normal uterine and ovarian endometriotic endometria, and the overexpression of Axl and Gas6 in endometriotic endometria. It is suggested that Gas6 and Axl signal transduction is aberrantly stimulated in endometriotic endometria, and is plausibly related to its growth potential.     

~(131)I治疗Graves’病后发生甲低与TGA,TMA及TRAb的关系

目的 :从甲状腺自身免疫方面探讨1 3 1 I治疗甲亢的效果及甲低发生的因素。方法 :选择1 3 1 I治疗的88例Graves’病甲亢患者随访 3年 ,分为第 1组 (TGA、TMA、TRAb均阳性 )和第二组 (TGA、TMA阴性 ,TRAb阳性 )。采用x2 分析自身抗体水平与甲低发生的关系。结果 :1组甲低发生率为 31 4 % ,2组为 3 8% ,1组明显高于 2组 ,差异有显著性。结论 :TGA、TMA和TRAb水平与确定1 3 1 I剂量及甲低的发生关系密切。认为TGA、TMA水平高的患者应酌情减少1 3 1 I用量     

IL-17 Eliminates the Therapeutic Effects of Myelin Basic Protein-Induced Nasal Tolerance in Experimental Autoimmune Encephalomyelitis by Activating IL-6

Interleukin (IL)-17 is a proinflammatory cytokine primarily secreted by Th17 cells, which are a CD4⁺ T-cell subset. Th17 cells and IL-17 are important in the pathogenesis of multiple sclerosis and in its established animal model, experimental autoimmune encephalomyelitis (EAE). However, it is unclear whether IL-17 contributes to EAE immune tolerance. We used the myelin basic protein (MBP) peptide MBP 68–86 to induce nasal tolerance to EAE, and simultaneously interfered with the tolerance by treatment with different doses of IL-17. We found that IL-17 dramatically interfered with MBP 68–86-induced immune tolerance. IL-17 administration increased IL-6 release, skewing T cell differentiation towards Th17 cells and decreasing the number of Treg cells. This led to an imbalance between Treg cells and Th17 cells and spurred the development of EAE.     

A proportion of proteinase 3 (PR3)-specific anti-neutrophil cytoplasmic antibodies (ANCA) only react with PR3 after cleavage of its N-terminal activation dipeptide

ANCA directed against PR3 are highly specific for Wegener's granulomatosis and microscopic polyangiitis, and have been implicated in the pathogenesis of small vessel vasculitis. Most PR3-ANCA are directed against conformational epitopes on PR3. This study was designed to determine whether the cleavage of the N-terminal activation dipeptide of PR3 is required for the binding of PR3-ANCA. Recombinant PR3 (rPR3) variants were expressed in the epithelial cell line, 293. As confirmed by radiosequencing, the rPR3 secreted into the 293 cell culture supernatant is N-terminally unprocessed. Two enzymatically inactive rPR3 mutants were expressed in 293 cells: rPR3-S176A and δ -rPR3-S176A. rPR3-S176A contains the N-propetide Ala-2-Glu-1, δ -rPR3-S176A does not. Culture supernatants of rPR3-S176A and δ -rPR3-S176A expressing 293 cells were used as sources of target antigen for PR3-ANCA testing by capture ELISA. Forty unselected consecutive PR3-ANCA⁺ sera were tested. With δ -rPR3-S176A as antigen all 40 were recognized, compared with only 34 of 40 when rPR3-S176A served as target antigen. The majority of the serum samples contained a mixture of antibodies reacting with epitopes accessible on the mature and on the proform of PR3. In conclusion, the cleavage of the N-terminal activation dipeptide of PR3 is not an absolute requirement for recognition by all PR3-ANCA. However, a substantial proportion of PR3-ANCA recognize (a) target antigen(s) exposed only after the conformational change of PR3 associated with the N-terminal processing. In 15% of sera this PR3-ANCA subset occurred exclusively. PR3-ANCA subtypes can be differentiated using specifically designed rPR3 variants as target antigens, and non-haematopoietic mammalian cells without regulated secretory pathway can be used for their expression.     

ZNF268, a novel kruppel-like zinc finger protein, is implicated in early human liver development

The advancement in gene knockout and transgenesis have brought about enormous improvement in our understanding of mouse embryogenesis in the past decade or so. On the other hand, relatively little is known about human embryogenesis due largely to the lack of easy access to human embryos and tissues for biomedical studies. We have previously isolated a novel zinc finger gene, ZNF268, from a 3-week-old human embryo cDNA library in an effort to identify genes important for human embryonic development. To investigate the potential involvement of ZNF268 in human embryogenesis, we report here the spatial and temporal regulation of its expression during development. Northern blot and Western blot analyses revealed that ZNF268 is expressed in early embryos, predominantly, if not exclusively, in fetal liver with little detectable expression in other fetal organs. Interestingly, unlike most zinc finger proteins, ZNF268 protein was found to be localized mainly in the cytoplasm of embryonic hepatocytes. This subcellular localization was substantiated by the localization of EGFP-ZNF268 fusion protein overexpressed in the transfected COS7 cells. These results suggest that ZNF268 plays a role in early human liver development most likely by functioning through a cytoplasmic mechanism.     

辽宁锡伯族和汉族前额发际的基因频率

本文调查了辽宁锡伯族及汉族群体的前额发际出现率和基因频率分布,同时也进行了各民族间出现率及基因频率的比较.研究结果表明:辽宁锡伯族前额发际平齐出现率71.88%、隐性基因频率0.8478;汉族前额发际平齐出现率74.88%、隐性基因频率0.8653.两民族前额发际平齐出现率及基因频率性别间无显著差异.与国内其他民族的相比,辽宁锡伯族及汉族群体前额发际平齐出现率及基因频率均处于较高水平.