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  • 1
    ISSN: 1573-2568
    Keywords: IBD ; ulcerative colitis ; growth factors ; growth factor receptors ; gene expression ; PDGF-R-β
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract A link between inflammation of the colon in inflammatory bowel disease (IBD) and the increased risk of colon cancer in ulcerative colitis (UC) may be provided by growth factor receptor genes. Their expression may be altered in response to growth factors present in the mucosa, and this, in turn, may induce further genetic changes, linked to carcinogenesis, in the cells of the colonic epithelium. To test this hypothesis, we assayed steady-state levels of eight growth factor receptor mRNAs in colonic epithelial cells of IBD patients and controls. Four of these genes (EGF-R, IGFI-R, CSF1-R, andPDGF-R-β) were expressed in epithelial cells, whereas four (erbB-2, erbB-3, NGF-R, andmet) were not. The level of the former in involved or uninvolved IBD was considerably lower than in normal epithelial cells from either sporadic colon cancer or diverticulitis patients. In contrast, expression was much higher in IBD patients with colon tumors than in active chronic IBD. The level of PDGF-R-β mRNA was two- to fourfold higher in involved than in uninvolved areas of the colons of two UC patients, but not in one Crohn's disease patient. Message abundance of its ligand,PDGF-β, however, was the same in paired UC samples. The pattern of expression ofPDGF-β andcripto was identical to that ofEGF-R, whereas the level of mRNA of amphiregulin was the same in active chronic IBD and IBD patients with tumors. A fourth growth factor,Kfgf, was not expressed. Increased levels of PDGF-R-β mRNA in involved UC relative to uninvolved UC may be related to the disease process in UC. Decreased expression of growth factor- and growth factor receptor-encoded mRNA in active chronic IBD may be related to the disease process, or it may be an effect of steroid therapy undergone by these patients. Enhanced expression of these genes in IBD patients with tumors compared to those without tumors suggests that this may be a marker for development of colon cancer in IBD.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1573-2568
    Keywords: inflammatory bowel disease ; ulcerative colitis ; protooncogenes ; gene expression ; c-fos ; c-abl ; c-yes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Protooncogenes are cell cycle-related genes that are involved in cell growth or proliferation. Alterations in the level of expression of these genes, or expression of aberrant gene products, have been observed in tumors and precancerous conditions. To determine if expression of these genes is altered in patients with inflammatory bowel disease (IBD)-who are at risk for development of colon cancer—we assayed transcripts of 15 protooncogenes in colonic epithelial cells of IBD patients and controls. Nine, of these genes (H-ras, c-myc, c-fos, c-jun, junB, N-myc, c-abl, c-yes, andp53) were expressed in epithelial cells, whereas two (RB1 and N-ras) were not. Expression of four other genes (c-src, K-ras, c-raf and c-myb) was observed, but the intensity of these bands was too low for densitometric analysis. The steady-state levels of transcripts of H-ras and five nuclear protooncogenes (c-myc, c-fos, c-jun, junB, and N-myc) were lower in epithelial cells from involved or uninvolved IBD samples than in normal epithelial cells from either sporadic colon cancer or diverticulitis patients. The level of c-fos mRNA was two-to threefold higher in involved than in uninvolved areas of the colons of two ulcerative colitis (UC) patients, but not in one Crohn's disease (CD) patient. Message abundance of c-abl transcripts was two-to threefold lower in UC epithelial cells than in either the CD or control samples. The steady-state level of c-yes-encoded mRNA was considerably higher in IBD patients resected for colon cancer than in patients resected for active chronic IBD or in controls. The level ofp53 message was constant in these samples. Increased levels of c-fos mRNA in involved UC relative to uninvolved, UC may be related to the disease process. Decreased expression of c-abl transcripts in UC may be a diagnostic marker for UC and may be related to the rate of cell turnover in these diseases. Enhanced expression of c-yes in IBD patients with tumors compared to active chronic IBD and controls suggests that expression of this gene may be a marker for development of colon cancer in IBD.
    Type of Medium: Electronic Resource
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  • 3
    Publication Date: 2021-06-30
    Description: The overall goal of this assessment was to evaluate the effects of nutrient-source reductions that may be implemented in the Mississippi River Basin (MRB) to reduce the problem of low oxygen conditions (hypoxia) in the nearshore Gulf of Mexico. Such source reductions would affect the quality of surface waters—streams, rivers, and reservoirs—in the drainage basin itself, as well as nearshore Gulf waters. The task group’s work was divided into addressing the effects of nutrient-source reductions on: (1) surface waters in the MRB and (2) hypoxia in the Gulf of Mexico.
    Keywords: Ecology ; Environment ; Fisheries ; Management
    Repository Name: AquaDocs
    Type: monograph
    Format: application/pdf
    Format: application/pdf
    Format: 130
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