Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0033036 (APC)
 10,214 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Platelet activating factor (PAF) derived from antigen-stimulated, IgE-sensitized rabbit basophils acts on platelets to induce aggregation and secretion of their content of granule-bound vasoactive amines. Despite this, PAF did not activate platelet factor 3. In contrast, collagen induced aggregation, secretion and PF3 activation in the washed platelets. Other stimuli (ADP, C3b, thrombin) also initiated both secretion and PF3 activation. A wide dose range of PAC, including those giving maximal secretion and aggregation, were ineffictive in making PF3 available and the possibility that PAF inhibited PF3, or its generation, was also excluded. It is concluded that PAF is a unique stimulus for platelets and that secretion and aggregation are not necessarily accompanied by PF3 generation.
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PMID:Activation of platelets by platelet activating factor (PAF) derived from IgE-sensitized basophils. IV. PAF does not activate platelet factor 3 (PF3). 97 40

Two sets of ((resistant x susceptible) F1----parent) and (parent----F1) chimeric mice were prepared. In the chimeric combinations involving BALB/c and DBA/1 mice, all (F1----F1) chimeras developed arthritis as well as potent anticollagen responses after immunization with collagen, whereas all (F1----BALB/c) and (BALB/c----F1) chimeras induced neither arthritis nor immune responses. This type of F1 T cells could be activated with APC from DBA/1 but not from BALB/c mice. Thus, the failure of the [F1 in equilibrium with BALB/c] chimeras to mount anticollagen responses was due to a defect at the APC level. Another arthritis-resistant strain, C57BL/6, exhibited adequate APC function, but reduced T cell responsiveness, representing an intermediate responder. In the chimeric combinations involving C57BL/6 and DBA/1 mice, (F1----F1) and (C57BL/6----C57BL/6) chimeras developed very high and very low incidence of arthritis, respectively. (C57BL/6----F1) chimeras developed an appreciable incidence of arthritis under conditions in which this group of chimeras generated intermediate levels of anticollagen responses. In contrast, (F1----C57BL/6) chimeras developed low incidence of disease despite induction of strong responses. Moreover, cells from collagen-immunized (F1----C57BL/6) chimeras, when transferred into T cell-depleted B cell mice of F1 or C57BL/6 strain, produced comparable immune responses in both groups but induced much more severe arthritis in F1 than in C57BL/6 recipients. These results indicate that: i) two types of arthritis-resistant strains can be identified, each of which has anticollagen APC defect as a low responder and reduced T cell responsiveness as an intermediate responder and ii) a discrepancy between the degree of anticollagen responses and clinical arthritis is attributed to the differential susceptibility to anticollagen immune responses.
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PMID:Type II collagen-induced murine arthritis: induction of arthritis depends on antigen-presenting cell function as well as susceptibility of host to an anticollagen immune response. 157 34

T cells play a critical role in the development of collagen-induced arthritis (CIA). Immunization with heterologous (chick) type II collagen (cII) results in chronic inflammation with progressive damage to the joints. The expression of specific MHC Class II alpha beta dimers, including IAq, is critical to induction of disease. The alpha chains of IAq and IAp are identical in sequence. The IAq and IAp beta chains differ by only four amino acid residues: 85, 86, 88, and 89. However, mice of the H-2p haplotype are not susceptible to CIA. To examine the impact of these structural differences in IA molecules on T cell Ag recognition, we studied presentation of cII peptides and denatured cII by APCs obtained from H-2q and H-2p mice. We also assessed presentation of ovalbumin, myelin basic protein (MBP), and MBP peptides by these APC populations. H-2q APCs presented both peptides and proteins to our T cell hybrids. In contrast, APCs obtained from H-2p mice presented peptides, but were defective in the processing and/or presentation of protein Ags. We then altered pairs of the residues in IAq to those found in IAp using site-directed mutagenesis and transfected these constructs into M 12.C3 B cells. All transfectants were able to present peptides, but those expressing IAp were unable to present protein Ags. The use of transfectants expressing hybrid molecules (residues 85 and 86 from IAp, 88 and 89 from IAq, or vice versa) allowed us to localize the region responsible for this defect to residues 85 and 86 of the beta chain. The presence of IAp residues (glu and thr versus gly and val in IAq) at these sites severely compromised the capacity for protein presentation. Resistance to CIA in H-2p haplotype mice may be a reflection of the limited repertoire of epitopes to which these mice can respond relative to susceptible H-2q mice.
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PMID:Polymorphism in the beta chain of IAq versus IAp influences presentation of protein but not peptide antigens. 755 84

The T-cell compartment was investigated in two high antibody responder lines of mice respectively susceptible (HI) and resistant (HII) to chicken collagen (CII)-induced arthritis (CIA). Previous data had shown that both lines were high anti-CII Ab producers, without any TCR V-beta gene defect or membrane expression impairment. The present studies demonstrate that anti-CII proliferation is much lower in HII than in HI. These results are confirmed by the limiting dilution analysis of anti-CII T-precursor frequencies (1/991 in HI and 1/12175 in HII). The percentage of CD8+ T cells is constitutively higher in HII mice, this difference increasing after CII immunization. This finding suggests a suppressive effect accounting for resistance to CIA. However, no restoration of specific response was achieved by in-vivo or in-vitro depletion of CD8+ T cells. T clones specific for Chicken CII could be obtained only from primed HI mice. Four of five clones with CD8+ phenotype proliferated in vitro to native and denatured CII and showed cytotoxic function in an anti-CD3 redirected assay. The CD4+ clone was shown to proliferate on both HI and HII-pulsed APC, which rules out a major CII processing/presentation defect in HII.
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PMID:T-cell compartment involvement in two high antibody responder lines of mice (HI and HII Biozzi mice) respectively susceptible and resistant to collagen-induced arthritis. 769 68

Accumulating evidences that carcinogenesis requires multiple gene alterations of oncogenes and tumor suppressor genes have recently emerged. In addition, genes related to invasion and metastasis are also important in understanding development of colorectal cancer. In this study, clinical significance and application of tumor suppressor genes and invasion related genes such as APC (adenomatous polyposis coli), DCC (deleted in colorectal carcinoma) tumor suppressor genes and invasion related gene, matrilysin were studied. In the mouse tumor induced by mutagen contained in cooked food, PhIP (2-amino-1-methyl-6- phenylimidazo [4,5-b] pyridine), nonsense mutations of APC gene that is similar to human colorectal cancer have been observed. These results suggested the quite interesting issue of mutagen contained in daily food having etiological role of colorectal cancer. DCC gene alteration, decreased expression of DCC mRNA was detected in 60% of advanced colorectal cancer. In all cases with liver metastasis, DCC expression was absent or markedly decreased, a finding that detection of DCC expression have an clinical importance that predicts metastatic potential of colorectal cancer. Matrilysin, the member of MMPs (matrix metalloproteinases) which degrade matrix components such as type IV collagen, laminin or fibronectin. In most of colorectal cancer, matrilysin was overexpressed in tumor cells. Matrilysin-transfected colorectal cancer cells showed more invasive ability in vitro and gained metastatic potential in SCID mice. Suppression of matrilysin expression by treated with all-trans retinoic acid (ATRA) or introduction of anti-sense matrilysin decreased the invasive ability in vitro. This result suggests that matrilysin plays an important role in invasion and metastasis and have a possibility of new anti-invasion therapy.
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PMID:[Genetic diagnosis of colorectal cancer]. 872 69

Little is known about the the signalling pathways driving the adenoma-to-carcinoma sequence in human colonic epithelial cells. Accumulation and activation of the src tyrosine kinase in colon cancer suggest a potential role of this oncogene in this early progression. Therefore, we introduced either activated src (m-src), polyoma-MT alone or combined with normal c-src in the adenoma PC/AA/C1 cell line (PC) to define the function and phenotypic transformations induced by these oncogenes in familial adenomatous polyposis (FAP) colonic epithelial cells. Functional expression of these oncoproteins induced the adenoma-to-carcinoma conversion, overexpression of the hepatocyte growth factor (HGF) receptor Met, but failed to confer invasiveness in vivo and in vitro, or to produce alterations in cell proliferation and differentiation. In contrast, PC-msrc cells became susceptible to the HGF-induced invasion of collagen gels and exhibited sustained activation of the pp60src tyrosine kinase and Tyr phosphorylation of the 120-kDa E-cadherin, which was further increased by HGF Transcripts of HGF were clearly identified by reverse transcription-polymerase chain reaction (RT-PCR) and Southern blot in the parental and transformed PC cells, suggesting an autocrine mechanism. Taken together, the data indicate that: (1) experimental activation of src and PyMT pathways directly induces tumorigenicity and Met upregulation in a colon adenoma cell line; (2) HGF-activated Met and src cooperate in inducing invasion; (3) in view of the molecular associations between catenins and cadherin or the tumour-suppressor gene product APC, the cell adhesion molecule E-cadherin may constitute a downstream effector of src and Met.
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PMID:Progression of familial adenomatous polyposis (FAP) colonic cells after transfer of the src or polyoma middle T oncogenes: cooperation between src and HGF/Met in invasion. 901 33

The study of liver dendritic cells (DC) and their progenitors is restricted by the small numbers that can be isolated or propagated from normal hepatic tissue. We examined the ex vivo growth, phenotype, and function of these cells after the administration to mice of the recently cloned hemopoietic growth factor flt3 ligand (FL), which is highly effective in mobilizing stem/progenitor cells. FL treatment (10 microg/day for 10 days) resulted in a mean 14-fold increase in the absolute number of nonparenchymal cells recovered from collagenase-digested livers compared with the control value. Culture of these nonparenchymal cells in granulocyte-macrophage CSF (GM-CSF; 1000 U/ml) resulted in the early formation of proliferating cell clusters and maximal release (within 4-5 days) of markedly increased numbers of nonadherent, low buoyant density cells per liver. Maximal release of low buoyant density cells propagated from control livers was at the later time of 6 to 8 days. Cells from both sources were DEC-205+, CD11c+, MHC class II+, CD80(low) (i.e., low level of CD80), CD86(low) and CD40(low). This immature phenotype was linked to poor T cell allostimulatory activity, indicative of DC progenitors. Propagation of cells from livers of FL-treated mice in GM-CSF and IL-4 resulted in a more mature DC phenotype and function. Maturational changes were also observed following exposure of the GM-CSF-stimulated progenitors to type 1 collagen for 3 additional days. The ability of FL to boost production of large numbers of liver DC progenitors provides opportunities for the further study of these important APC in normal liver immunobiology and in immune-mediated hepatic disorders.
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PMID:In vivo administration of flt3 ligand markedly stimulates generation of dendritic cell progenitors from mouse liver. 937 22

Venous valves are more frequent in distal veins and venulae, providing a protecting action against blood skin reflux. Structurally simple, collagen and endothelium, they allow a cavity to be formed by distension, when occlusion occurs. Venous angioscopy can distinguish bicuspid floating valves, reinforced, reinforcing valves with free edges and seat valves as well as the presence of apertures of small collateral vessels in the sinus, of which they play a role in the filling up. Valves are inefficient in supine and in standing among 20% of the adult population. Sinuses allow vortices to be created, low recirculating zones, where blood flow move slowly in niches, at a low shear rate, independently from the main stream. A deep vortex is located in sinus, usually empty, but likely to receive red cell aggregates and leukocytes in the condition of stasis and hyperviscosity. Such a vortex is hypoxic, cause of endothelial activation. In such areas fibrin-leucocytic nidus are created, histologically recognized, of which sub-endothelium has become thick and thrombogenic. Two stages characterized its progression: stage I: a few alteration in the valves, little thrombin generation, taken over by the coagulation inhibitors: AT III, APC and TFPI. Stage II: damaged valves, local consumption of the inhibitors and extended generation of thrombin over the platelets, through factor IXa. Hereditary inhibitor deficits increase the risk (frequent factor Leyden V). When the coagulation cascade is considered, VIIa-tissue factor complex appears to be the thrombotic pathway, leading first to wall linked thrombin, uneasily reached by AT III and facteur IXa non inhibited by TFPI, therefore explaining the platelet extension. Monocytes, which can bear tissue factor, may be "lodged" inside the niches. Besides this important role in deep venous thrombosis, incompetent venous valves are responsible for the skin venous hypertension, a subsequent ground for ulcers. Their role in chronic venous insufficiency is uncertain. In the near future, venous angioscopy will bring about new findings about the pathophysiology of venous valves.
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PMID:[Venous valves in the legs: hemodynamic and biological problems and relationship to physiopathology]. 948 Mar 31

Excessive procoagulant activity in the alveolar space may play a relevant role in the pathogenesis of pulmonary fibrosis. Hypercoagulability results from the disruption of the balance between the procoagulant and anticoagulant factors. The aim of this study was to assess the levels of molecular markers of the anticoagulant protein C (PC) pathway in the bronchoalveolar lavage fluid (BALF) and plasma of 11 patients with idiopathic pulmonary fibrosis (IPF), 14 with sarcoidosis and 16 with collagen vascular disease (CVD)-associated interstitial lung disease (CVD-ILD). Six healthy nonsmoking volunteers served as control subjects. BALF concentrations of the marker of clotting activation, thrombin- antithrombin III complex (TAT), in patients with sarcoidosis and CVD-ILD were significantly greater than those in control subjects. PC levels in BALF were markedly higher in patients with IPF (610 +/- 150 ng/ml), sarcoidosis (680 +/- 170 ng/ml), and CVD-ILD (1,580 +/- 600 ng/ml) than in control subjects (230 +/- 140 ng/ml). BALF concentrations of activated PC-PC inhibitor (APC-PCI) complex were significantly decreased in IPF (0.46 +/- 0.16 ng/ml), sarcoidosis (0. 43 +/- 0.11 ng/ml), and CVD-ILD (0.50 +/- 0.15 ng/ml) patients as compared with control subjects (1.08 +/- 0.23 ng/ml). APC-PCI/PC ratios were significantly lower in patients with IPF (2.70 +/- 1.74 ng/microg), sarcoidosis (1.94 +/- 0.82 ng/microg), and CVD-ILD (1.89 +/- 0.68 ng/microg) than in control subjects (15.91 +/- 8.45 ng/microg). Plasma levels of APC- PCI and the APC-PCI/PC ratio were also significantly decreased in patients with CVD-ILD as compared with control subjects. Overall, these findings suggest that decreased PC activation with increased procoagulant activity occurs in patients with ILD.
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PMID:Protein C anticoagulant system in patients with interstitial lung disease. 962 Sep 17

This paper is the first in a series aimed at understanding the role of beta-catenin in epithelial-mesenchymal transformation (EMT) and acquisition of mesenchymal invasive motility. Here, we compare the expression of this and related molecules in the two major tissue phenotypes, epithelial and mesenchymal, the latter including normal avian and mammalian fibroblasts and malignant human uveal melanoma cells. Previously, it was proposed that src initiates EMT by tyrosine phosphorylation of the cadherin/catenin complex resulting in a negative effect on epithelial gene expression. On the contrary, we found that although beta-catenin becomes diffuse in the cytoplasm during embryonic EMT, the cytoplasmic beta-catenin of the embryonic and adult mesenchymal cells we examined is not tyrosine phosphorylated. Pervanadate experiments indicate that cytoplasmic PTPases maintain this dephosphorylation. GSK-3beta is present, but little or no APC occurs in normal and neoplastic mesenchymal cells. The function of the nonphosphorylated cytoplasmic beta-catenin in mesenchyme may be related to invasive motility. Indeed, in order to invade extracellular matrix, transitional (Mel 252) melanoma cells transform from an epithelial to a mesenchymal phenotype with increased cytoplasmic beta-catenin. Moreover, antisense beta-catenin and plakoglobin ODNs inhibit Mel 252 and corneal fibroblast invasion of collagen. All fibroblastic, transitional, and spindle melanoma cells contain nuclear as well as cytoplasmic beta-catenin, but they are not significantly more invasive than normal fibroblasts that contain only cytoplasmic beta-catenin.
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PMID:Tissue-specific expression of beta-catenin in normal mesenchyme and uveal melanomas and its effect on invasiveness. 982 3


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