The results reported here indicate that activated species of Hageman factor (HF, factor XII), a protein that mediates blood clotting, fibrinolysis, and activation of the complement cascade, induce elaboration ofinterleukin 1 (IL-1) by human monocytes. Augmentation of IL-1 production in mononuclear cell cultures was observed when HF was present along with lipopolysaccharide (LPS) but was not observed with HF alone. Furthermore, antiserum to HF abrogated the enhancement of IL-1 in cultures containing HF and LPS. Total IL-1 activity, which represents secreted and cell-aociated IL-1, was enhanced in LPS-stimulated mononuclear cultures by HF. In the absence of LPS, the initial activation product of HF, HFa, which contains the serine protease enzyme activity and the surface-binding domains of the protein, induced IL-1N protein and mRNA. In the presence of LPS, the enzymatic moiety (HFf), which is also contained in HF and HF, amplified IL-1 production. Induction and amplification of monocyte IL-I by HF provides further evidence for establishing a role for HF in the acute-phase reaction and the cellular immune response.
A repetitive element in C.elegans has been found that bears high homology to the element mariner of Drosophila mauritiana (EMBL accession number X77804). This element is present in about 20 copies in the N2 strain of C.elegans, and appears in roughly equal copy numbers in the related strain BO and in the hybrid strains RW7097 and TR679. There is only one copy of this MLE in three related species of Caenorhabditis. A cDNA of this mariner-like element (MLE) codes for a protein with 58% homology to the Drosophila transposase. The mariner-like element is not mobile in N2. This class of elements has now been described in insects, planaria and nematodes (GenBank accession number M98552 and this report).
R
f values in thin-layer chromatography (TLC) depend strongly on solvent saturation of the atmosphere above the liquid in the TLC developing chamber. Although there are a multitude of experiments in the literature that describe the use of TLC for the analysis of a mixture, we were unable to find one in which the student discovers the importance of maintaining the solvent atmosphere during development of a TLC plate. The experiment reported here illustrates the potentially dramatic effects on TLC R
f values of not equilibrating the solvent atmosphere during development.
MethodsHageman factor (HF, Factor XII) is activated by glass, collagen, and ellagic acid, and initiates blood coagulation via the intrinsic pathway. Clq inhibits collagen-induced platelet aggregation and adherence of platelets to glass, effects attributable to the collagenlike region of Clq. We examined the actions of Clq on HF activation. Incubation of Clq with HF before addition of HF-deficient plasma extended the activated partial thromboplastin time.Similarly, when glass tubes were coated with Clq before testing, the partial thromboplastin time of normal plasma was increased. Clq reduced the activation of HF by ellagic acid, as measured by the release ofp-nitroaniline from the synthetic substrate H-D-prolyl-L-phenylalanyl-L-arginine-p-nitroanilide dihydrochloride, an effect inhibited by monoclonal anti-human Clq murine IgG and by digestion of C1q by collagenase. Thus, Clq inhibits activation of HF in vitro in clot-promoting and amidolytic assays and suggests a regulatory mechanism for the inhibition of coagulation.
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