Tyrosine phosphorylation of a low molecular weight protein induced by RANTES in T-lymphocytes

The beta-chemokine RANTES, a T-lymphocyte activator, chemoattractant, and inducer of homotypic aggregation, is considered to exert extensive effects on T lymphocytes through either G protein-coupled or protein tyrosine kinase (PTK) signaling pathway. In the present study, we analyzed RANTES-induced signal transduction through PTK as an early event in T-lymphocyte activation. Tyrosine phosphorylation is detected by immunoblots in the human T-cell line H9 after incubation with human recombinant RANTES. The tyrosine phosphorylation of a protein with a molecular mass of about 25 kD is measurable as early as 30 s and maximal at 1-5 min; and is a dose-dependent effect. The phosphorylation response can be abrogated by the tyrosine-kinase inhibitor herbimycin A (HA) but is insensitive to heterotrimeric Galphai protein inhibitor pertussis toxin (Ptx). This phenomenon is also observed in a visible homotypic aggregation response after incubation serum-starved H9 cells with RANTES. The phosphorylation response can not be down-regulated by preincubation with either anti-CC chemokine receptor 5 (CCR5) antibody or HIV-1Bal supernatants. Our results suggest that tyrosine phosphorylation of a protein with molecular mass of about 25 kD via Src-family PTK(s) is an early event in T-lymphocyte activation associated with the homotypic aggregation in response to RANTES.     

耳穴静态电测量中的瞬变响应

耳穴电参数时变关系实验表明，在测量起始ｔ＜２τ时，因瞬变作用，电位Ｅ（ｔ）和压降Ｕ（ｔ）为瞬态响应，响应函数呈指数关系，特征参数为弛豫时间τ，τ≈ＲＣ；ｔ＞２τ时，为时变间期。电路分析给出数学描述，并与耳穴和模拟实验结果较相符。提示，时变特征应以ｔ＞２τ后提取，静态电测量时，采样应避开瞬变期，可提高准确性。该工作对正确鉴别时变性和特征提取，全面认识耳穴电特性具有重要意义。     

Ultrastructure of Amelanotic Melanocytes from Human Hair Follicles

Objective: To investigate the ultra structure of amelanotic melanocytes (AMMC). Methods: The hair follicles obtained from normal human scalp by 0.50% collagenase type V treatment were washed with 0.1mol/L phosphate buffer salt (PBS). Hair-follicle cell suspensions were prepared by trypsin treatment and cultured in melanocyte medium. Remaining keratinocytes were removed by differential trypsinization. 100μg/ml geneticin was used to eliminate the contaminating fibroblasts. At third passage, the cells were trypsinized, and then washed in phosphate-buffered saline and processed for transmission electron microscopy. Results: Under transmission electron microscope, the cultured cells showed round or oval shape, with single large nuclear and the karyotheca were double deck. There were obvious euchromosome within the nucleus, and sparse heterochromosome. There were various organelles in the cytoplasm, including plentiful melanosomes with nearly similar size, mitochondria, rough endoplasmic reticule (RER) and ribosome. The electron density granules in most of the melanosomes disposed along concentric circularities. Golgi apparatus in the cells was inconspicuous. Conclusion: The ultra structure of AMMC from human hair follicles is different from that of epidermal melanocytes, and these characteristics determine the functional immature of AMMC.     

Optimization of 3-D hepatocyte culture by controlling the physical and chemical properties of the extra-cellular matrices

Hepatocytes are anchorage-dependent cells sensitive to microenvironment; the control of the physicochemical properties of the extra-cellular matrices may be useful to the maintenance of hepatocyte functions in vitro for various applications. In a microcapsule-based 3-D hepatocyte culture microenvironment, we could control the physical properties of the collagen nano-fibres by fine-tuning the complex-coacervation reaction between methylated collagen and terpolymer of hydroxylethyl methacrylate-methyl methacrylate-methylacrylic acid. The physical properties of the nano-fibres were quantitatively characterized using back-scattering confocal microscopy to help optimize the physical support for hepatocyte functions. We further enhanced the chemical properties of the collagen nano-fibres by incorporating galactose onto collagen, which can specifically interact with the asialoglycoprotein receptor on hepatocytes. By correlating a range of collagen nano-fibres of different physicochemical properties with hepatocyte functions, we have identified a specific combination of methylated and galactosylated collagen nano-fibres optimal for maintaining hepatocyte functions in vitro. A model of how the physical and chemical supports interplay to maintain hepatocyte functions is discussed.     

骨折愈合塑形的力学机理I^＊——骨表面再造理论的应用

深入探讨长骨骨折愈合塑形阶段的力学机理,采用骨表面再造理论与有限元结合的方法。我们选取用应变能密度作为力学激励的骨表面再造理论,有限元分析采用三维的空间模型,利用我们编制的长骨表面再造系统“BRSS97”对长骨骨折愈合塑形阶段的三种类型：外骨痂型、骨内缺损型和骨外缺损型的力学机理进行研究。结果表明：骨痂可以完全吸收,骨缺损可以恢复,三种情况下骨均可以恢复到正常状态。由此说明长骨骨折愈合塑形过程就是骨材料对力学激励的适应过程。     

Galectin-1 and galectin-3 in chronic pancreatitis

Galectin-1 and galectin-3 have important functions in cell-cell interactions, cell adhesion to extracellular matrix, the organization of extracellular matrix, and tissue remodeling. To assess their potential role in chronic pancreatitis (CP), we examined their expression by Northern blot analysis, in situ hybridization, immunohistochemistry, and Western blot analysis in normal and CP pancreatic tissues. Northern blot analysis revealed a 4.5-fold increase of galectin-1 mRNA (p < 0.01) and a 3.8-fold increase of galectin-3 mRNA (p < 0.01) in CP samples compared with normal controls. In situ hybridization analysis of normal pancreas indicated low abundance of galectin-1 mRNA in fibroblasts, whereas galectin-3 mRNA was moderately present in ductal cells. CP samples exhibited moderate to intense galectin-1 mRNA signals in fibroblasts, whereas galectin-3 mRNA signals were intense in the cells of ductular complexes and weak in the degenerating acinar cells. In addition, intense galectin-1 and galectin-3 mRNA signals were present in nerves of normal and CP samples. Immunohistochemistry showed a distribution pattern of galectin-1 and galectin-3 similar to that described for in situ hybridization. Relative quantification of galectin-1 and galectin-3 protein by immunoblotting revealed an increase of 3.2-fold and 3.0-fold, respectively, in CP compared with normal controls. There was a significant correlation between galectin-1 and fibrosis and between galectin-3 and fibrosis and the density of ductular complexes. Up-regulation of galectin-1 in fibroblasts and galectin-3 in ductular complexes suggests a role of these lectins in tissue remodeling in CP. Galectin-1 might participate in ECM changes, whereas galectin-3 seems to be involved in both ECM changes and ductular complex formation.     

Molecular and genetic characterizations of five pathogenic and two non-pathogenic monoclonal antiphospholipid antibodies

Antiphospholipid syndrome (APS) is an autoimmune disease that is characterized by thrombosis, recurrent fetal loss and thrombocytopenia. Antiphospholipid antibodies, detected by enzyme-linked immunoabsorbent assays (aCL) and/or in vitro blood clotting assays (LAC) are strongly associated with APS. Both the molecular structures used by pathogenic antiphospholipid antibodies and the genetic mechanisms leading to their production are unknown. We describe here the variable region genes of seven IgG antiphospholipid antibodies derived from two APS patients. Of these, five are pathogenic as defined in a mouse model of thrombosis and two are not. Analyses of the expressed variable region genes show no preferential V gene usage. However, similar to anti-DNA antibodies, pathogenic antiphospholipid antibodies contain an increased number of arginine residues in the third complimentarity-determining region (CDR3) of their H chains. The increased accumulation of arginine residues in the V(H) CDR3 may act to enhance antigen binding, promote disease and point to the importance of the H chain in the pathogenic potential of certain antiphospholipid antibodies.     

Biochemical and biophysical analysis of heptad repeat regions from the fusion protein of Menangle virus,a newly emergent paramyxovirus

E. coli in vitro expression system. The GST-removed purified 2-Helix protein could form a stable trimer in vitro judging by gel-filtration and chemical cross-linking. CD spectra showed that the 2-Helix protein had a high percentage of α-helix and was very thermo-stable. Crystals of the 2-Helix protein preparations have been obtained in many conditions with hanging-drop diffusion method. These results indicated that Menangle virus has the common features of the fusion protein for other paramyxoviruses and should adopt a similar fusion mechanism to other members. As the HR regions of Menangle virus F protein could form stable six-helix bundle coiled coil structure, they should be used as drug target for the design of fusion inhibitors, as successfully used for other parmyxoviruses. This is especially relevant to such a newly emergent virus with zoonotic potentials. Received January 23, 2003; accepted February 28, 2003 Published online April 28, 2003     

用小波变换提取视觉诱发电位信号

视觉诱发电位（ＶＥＰ）信号的动态提取及处理具有重要的临床意义。通过硬件采集的ＶＥＰ信号经过叠加平均处理后仍含有大量背景噪声，不能直接用于诊断分析。小波变换是一种新兴时频分析方法，适于分析非平稳信号。在我们研制的视觉生理地形图系统中，成功地用它从背景噪声中提取出ＶＥＰ信号，完成信号的预处理。