Hepatic Artery Anatomic Variations and Reconstruction in Liver Grafts Procured in Greece: The Effect on Hepatic Artery Thrombosis

Aims

Variations of the anatomy of donor hepatic arteries increase the number of arterial anastomoses during liver transplantation and, possibly, the incidence of hepatic artery thrombosis (HAT). In this study, we describe the arterial anatomic variations in liver grafts procured and transplanted by a single center in Greece, the techniques of arterial anastomosis, and their effect on the incidence of early HAT.

gp49B1 suppresses stem cell factor-induced mast cell activation-secretion and attendant inflammation in vivo

We report that gp49B1, a mast cell membrane receptor with two immunoreceptor tyrosine-based inhibitory motifs (ITIM), constitutively inhibits mast cell activation-secretion induced by stem cell factor (SCF), a tissue-derived cytokine that also regulates mast cell development. The intradermal injection of SCF into the ears of gp49B1 null (gp49B(-/-)) mice elicited approximately 4- and 2.5-fold more degranulating mast cells and tissue swelling caused by edema, respectively, than in gp49B(+/+) mice. SCF did not induce tissue swelling in mast cell-deficient mice, and the responsiveness of gp49B(-/-) mice to mast cell-associated amine and lipid mediators was unaltered. When gp49B(+/+) and gp49B(-/-) mice were pretreated with antagonists of the amines, SCF-induced tissue swelling was reduced by >90% and 60%, respectively, and it was reduced by >90% in both genotypes when a cysteinyl leukotriene receptor antagonist was also provided. Hence, the dominant contribution of secretory granule amines to SCF-induced tissue swelling is the result of gp49B1-mediated inhibition of the production of cysteinyl leukotrienes by mast cells. Our findings also provide the first example of an ITIM-bearing receptor that constitutively suppresses inflammation generated in vivo independently of the adaptive immune response by a receptor that signals through intrinsic tyrosine kinase activity rather than immunoreceptor tyrosine-based activation motifs.     

Subtyping of MRSA isolates belonging to a widely disseminated clonal group by polymorphism of the dru sequences in mec-associated DNA

During the past 7 years the "Berlin epidemic MRSA" has spread throughout whole Germany. SmaI macrorestriction patterns of this clonal group are rather stable as are the length polymorphisms at the 3' end of the coagulase gene and the x-region of spa. However, the dru region (direct repeat units) of mec-associated DNA exhibits a length polymorphism due to deletion of one or more direct repeat units. Five different subclones could be discriminated by dru region length polymorphism. Location of deletions and of a few point mutations allow a delineation of these subclones.     

Parameters for optimizing detection of transforming growth factors

Summary Transforming growth factors (TGF) induce the soft agar growth of nontransformed cells, such as NRK-49F cells. This report describes culture conditions that optimize the detection of TGF by NRK-49F cells. Two aspects are dealt with in depth: the need to select an appropriate clone of NRK-49F cells and the need to select a culture medium that supports little or no background growth in the absence of added TGF. Evidence is presented to demonstrate that medium supplemented with heat-treated, dialyzed bovine plasma provides better conditions for assaying TGF than serum-supplemented medium provides.     

Ly49 gene expression in different inbred mouse strains

Mouse natural killer cells express receptors for class IMHC in the form of the Ly49 family of proteins. The Ly49 family contains at least 13 expressed members (A, B, C, D, E, F, G, H, I, J, L, O, and P) and is further subdivided into activating and inhibitory subfamilies based on intracellular and transmembrane characteristics. The level of sequence identity between different members varies dramatically. However, comparison of the extracellular domain has revealed that several of the Ly49 molecules also form “pairs,” where one member is activating and the other is inhibitory. Until recently, most Ly49 molecules described have come from the C57B1/6 strain of inbred mice. Using molecular cloning and immunochemical analysis we have found that different mouse strains express novel Ly49 molecules. Comparison of the allelic forms of some Ly49 molecules has shown that the dividing line between different genes and different alleles is blurred. This project has been funded in whole or in part with federal funds from the National Cancer Institute, National Institutes of Health, under Contract No. NO1-CO-56000. Animal care was provided in accordance with the procedures outlined in A Guide for the Care and Use of Laboratory Animals (National Institutes of Health Publication No. 86-23, 1985). The content of this publication does not necessarily reflect the views or policies of the Department of Health and Human Services, nor does mention of trade names, commercial products, or organizations imply endorsement by the U.S. government.     

Structural and functional characterization of myotoxin I, a Lys49 phospholipase A2 homologue from the venom of the snake Bothrops atrox.

A new myotoxin was isolated from the venom of Bothrops atrox from Colombia. B. atrox myotoxin I is a homodimer, with a subunit molecular mass of 13,826, and a pI of 8.9. Its complete nucleotide sequence was obtained by cDNA cloning, indicating a mature product of 122 residues that belongs to the family of Lys49 phospholipase A(2) (PLA(2)) homologues, a subgroup of catalytically inactive proteins within the group IIA. Accordingly, the toxin was devoid of phospholipase and anticoagulant activities, in vitro. In mice, it induced conspicuous local myonecrosis, edema, and a systemic interleukin-6 response. In vitro, it was cytolytic upon myoblasts, and weakly bactericidal. The toxin showed highest homology with other Lys49 PLA(2)s, both in its primary and three-dimensional modeled structure, although with an evident difference in the C-terminal region. Unlike Lys49 proteins of American crotalids having 121 residues, this toxin presents an insertion (Asn) between positions 118 and 119. Despite several substitutions within the C-terminal region 115-129 between B. atrox myotoxin I and B. asper myotoxin II, antibodies against synthetic peptide 115-129 of the latter were strongly cross-reactive to the former, indicating the antigenic conservation of this site, known to be critical for the membrane-damaging activities of Lys49 myotoxins.     

活性多酚化合物LM49对RAW264.7巨噬细胞极化的影响

目的初步探讨LM49(2,4'三羟基-5,2'-二溴二苯甲酮)对脂多糖(LPS)联合干扰素γ(IFN-γ)诱导的小鼠单核巨噬细胞(RAW264.7)M1/M2极化的影响及其调控机制。方法四曱基偶氮唑蓝(MTT)法测定LM49对细胞活力的影响;流式细胞术、实时荧光定量聚合酶链反应(PCR)和Westem-blot法测定LM49(5,10,20μmol·L^-1)与LPS/INF-γ共同作用于RAW264.7细胞后,巨噬细胞亚型标志物的表达情况及对核因子(NF)-κB和JAK/STAT信号通路的影响。结果与LPS/INF-γ造模组相比,LM49显著抑制CD16/32^+细胞数及诱导型一氧化氮合酶(iNOS)、白细胞介素(IL)4和肿瘤坏死因子(TNF)-αmRNA的表达,升高CD206^+细胞数及Arg-1和IL-10 mRNA的表达,且降低巨噬细胞M1/M2的比值;Westem-blot法验证LM49可显著降低TLR4、Myd88、NF-κB和STAT1蛋白的表达量,同时抑制p-JAK2和p-STATl蛋白磷酸化水平。结论LM49通过抑制TLR4-Myd88-NF-κB和JAK2-STAT1信号通路,抑制巨噬细胞Ml型极化及促进巨噬细胞M2型极化,调节巨噬细胞M1/M2的平衡。     

大鼠自然杀伤细胞凝集素样受体Ly49s3

自然杀伤（NK）细胞是体内重要的免疫细胞，而其表面的活化性受体在其发挥相应生物学功能中扮演了关键的角色。其中Ly49s3是广泛表达在多种品系大鼠NK细胞上的杀伤凝集素样受体（KLR）家族的成员，由大鼠4号染色体NKC编码，可通过识别相应的MHC Ⅰ类分子，向NK细胞传导活化性信号，激活NK细胞发挥相应的生物学功能。