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Query: UMLS:C0699790 (colon cancer)
 28,837 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The role which the human colon fulfils in digestion and metabolism remains largely undocumented. Its capacity to conserve water and electrolytes is well known although how this is controlled is uncertain. In the animal kingdom, calcium and magnesium absorption from the colon are improtant as are absorption and synthesis of vitamins. The abundant microflora of the human colon gives it unique properties. Dietary residue is metabolised forming short-chain fatty acids, hydrogen, carbon dioxide and methane; whilst 20% of urea synthesised in man is broken down in the colon to ammonia, which is reabsorbed, and carbonic acid. The microflora also degrades a wide variety of organic compounds including food additives, drugs, bile salts, and cholesterol which may be relevant to the development of colon cancer. Regional differences in colonic function also exist making interpretation of data from this relatively inaccessible organ more difficult.
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PMID:The colon: Absorptive, seccretory and metabolic functions. 120 9

Transcriptional activation of human heat shock protein (HSP) genes by heat shock or other stresses is regulated by the activation of a heat shock factor (HSF). Activated HSF posttranslationally acquires DNA-binding ability. We previously reported that quercetin and some other flavonoids inhibited the induction of HSPs in HeLa and COLO 320DM cells, derived from a human colon cancer, at the level of mRNA accumulation. In this study, we examined the effects of quercetin on the induction of HSP70 promoter-regulated chloramphenicol acetyltransferase (CAT) activity and on the binding of HSF to the heat shock element (HSE) by a gel mobility shift assay with extracts of COLO 320DM cells. Quercetin inhibited heat-induced CAT activity in COS-7 and COLO 320DM cells which were transfected with plasmids bearing the CAT gene under the control of the promoter region of the human HSP70 gene. Treatment with quercetin inhibited the binding of HSF to the HSE in whole-cell extracts activated in vivo by heat shock and in cytoplasmic extracts activated in vitro by elevated temperature or by urea. The binding of HSF activated in vitro by Nonidet P-40 was not suppressed by the addition of quercetin. The formation of the HSF-HSE complex was not inhibited when quercetin was added only during the binding reaction of HSF to the HSE after in vitro heat activation. Quercetin thus interacts with HSF and inhibits the induction of HSPs after heat shock through inhibition of HSF activation.
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PMID:Inhibition of the activation of heat shock factor in vivo and in vitro by flavonoids. 132 38

Orotic acid, first discovered in ruminant milk, is an intermediate in the pyrimidine biosynthesis pathway of animal cells. Its synthesis is initiated by the formation of carbamoyl phosphate (CP) in the cytoplasm, with ammonia derived from glutamine. Ureotelic species also form CP in the first step of urea synthesis in liver mitochondria. For that, ammonia is derived from tissue fluid. When there is insufficient capacity for detoxifying the load of ammonia presented for urea synthesis, CP leaves the mitochondria and enters the pyrimidine pathway, where orotic acid biosynthesis is stimulated, orotic acid excretion in urine then increases. Orotic acid synthesis is abnormally high with hereditary deficiencies of urea-cycle enzymes or uridine monophosphate synthase. It is also elevated by ammonia intoxication and during feeding of diets high in protein, high in lysine with respect to arginine, or deficient in arginine, ornithine, and citrulline. Rats fed 1% orotic acid or diets deficient in urea-cycle amino acids develop fatty livers, which has not been demonstrated in other species. Humans consuming 6 g of orotic acid daily have not shown adverse effects. Rats fed 1% orotic acid or arginine-deficient diets also showed more and larger foci positive for gamma-glutamyl transpeptidase and more liver tumors after administration of carcinogens and partial hepatectomy. Orotic acid feeding was also associated with the tendency for development of larger mammary tumors induced by chemical carcinogens in rats and with development of urinary bladder calculi containing high concentrations of orotic acid in mice. Conditions that raise tissue orotic acid change purine-pyrimidine ratios. It is unknown whether tissue orotate concentrations play a role in the recently observed enhanced proliferation of cells in the colon of rats fed high-protein, high-fat diets or in the promotion of chemically induced colon cancer by intrarectal administration of ammonium acetate.
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PMID:Nitrogen-stimulated orotic acid synthesis and nucleotide imbalance. 154 44

The relationship between preoperative intravenous pyelogram (IVP) and urologic complications after potentially curative operations for carcinoma of the colon and rectum was studied in 511 patients who underwent operation from 1976 to 1983. Forty per cent of the patients had preoperative IVP and these patients were significantly more likely to have undergone resection distal to the transverse colon than patients without preoperative IVP. Sex, age, urologic history, physical findings, abnormal urinalysis, elevated blood urea nitrogen (BUN) or serum creatinine levels and identity of the surgeon did not appear to influence whether or not an IVP was obtained before operation. Postoperative urologic complications were noted in 9.4 per cent of the patients; 87 per cent of the complications were retention or infection. Complications were significantly more common in male patients, particularly those with preoperative symptoms of retention, patients with elevated preoperative BUN or serum creatinine levels and patients who had resections distal to the transverse colon. Age, urologic history, physical findings, abnormal urinalysis results and the identity of the surgeon were not associated with postoperative urologic complications. The incidence of complications was the same in patients with normal and abnormal IVP results as well as for patients who did not undergo IVP. The findings of this study do not support the routine use of preoperative IVP for patients who undergo potentially curative resection for carcinoma of the colon and rectum.
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PMID:The role of preoperative intravenous pyelogram in operations performed for carcinoma of the colon and rectum. 372 28

Selected biochemical parameters (serum protein, albumin, prealbumin, total retinol-binding protein, vitamins A and E, total carotenoids, and urinary urea and creatinine) were determined in healthy, free-living vegetarian and nonvegetarian subjects. The groups studied were composed of Seventh-day Adventist pure vegetarians, Seventh-day Adventist lacto-ovo vegetarians, Seventh-day Adventist nonvegetarians, and general population nonvegetarians. No values indicative of nutritional deficiencies were observed in any of the subjects. Serum carotenoid levels were significantly higher in Seventh-day Adventist pure vegetarians than in members of the other groups. Mean values for serum vitamin A showed no differences between the dietary groups, although 41% of general population nonvegetarian subjects (the group considered at highest risk for colon cancer) had serum vitamin A levels in the upper quartile of the distribution. From these data no conclusions can be drawn relating to the role of dietary habits as determinants of colon cancer risk.
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PMID:Diet, nutrition intake, and metabolism in populations at high and low risk for colon cancer. Selected biochemical parameters in blood and urine. 654 31

The effect of alterations in the quality and quantity of dietary fat on N-nitrosomethyl urea (NMU)-induced colon cancer in rats was studied. Weanling Sprague-Dawley rats were fed semipurified diets containing 24% beef fat, 24% corn oil, 24% Crisco or the three fats in equal parts to make a total of 5% fat. Macronutrients and micronutrients were adjusted to balance the nutrient to calorie ratios. After 4 weeks of dietary treatment, all rats, except vehicle-treated animals received NMU (1.5 mg) via intrarectal instillation, twice a week for 2 weeks. The animals continued receiving the experimental diets until intestinal tumors developed and surviving animals were sacrificed at 43 weeks. There was no effect of any of the high fat diets tested on intestinal tumor incidence, latency, distribution or size. Cumulative probability of death with colon carcinoma did not differ significantly among the dietary groups.
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PMID:Lack of effect of dietary fat on N-nitrosomethyl urea (NMU)-induced colon tumorigenesis in rats. 669 42

Wistar-Furth (WF) strain rats have been shown to have a high incidence of spontaneous colon cancer. We have compared the alkaline phosphatase (AP) isoenzymes in colonic carcinomas of these inbred WF strain rats with the isoenzymes in the non-carcinomatous colon of the same strain and the normal colon of Wistar strain rats, from which the WF strain was derived. On electrophoresis of AP specimens partially purified by acetone fractionation, the non-carcinomatous colon was found to have three main isoenzymes, while the normal colon had two. Colonic carcinomas gave one band which migrated slower than any bands from either normal or non-carcinomatous colon. The electrophoretic mobility of AP from colonic carcinomas was retarded by neuraminidase treatment. This did not influence the isoenzymes from non-carcinomatous and normal colon. The inhibition patterns of the enzyme from colonic carcinoma by amino acids, inorganic phosphate and urea were different from those of the isoenzymes in the other two tissues. AP of colonic carcinoma was also the most heat-labile. There were no significant differences in the enzymic properties of the isoenzymes from non-carcinomatous and normal colon. The enzymic properties except for electrophoretic mobility were found to be the same between APs of colonic carcinoma and the placenta.
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PMID:Alkaline phosphatase isoenzyme of colonic carcinoma in Wistar-Furth rats. 713 19

Immunochemical detection of proteins with antigenic determinants that are dependent on the native spatial conformation of the protein can often pose problems with conventional two-dimensional polyacrylamide gel electrophoresis (2-DE). For example, many antigenic determinants are readily destroyed by reducing agents and/or urea, reagents which are critical components of many of the conventional isoelectric focusing and immobilized-pH-gradient (IPG) protocols used in the first electrophoretic dimension. Here we describe the use of commercially available precast 2-DE gels for performing nonreducing/non-urea 2-DE of proteins extracted from the human colon cancer cell line LIM 1215 with 0.3% Triton X-100 that permit the identification of antigens with conformational determinants by immunoblot analysis. Previous, related studies demonstrated the usefulness of peptide-mass fingerprinting for identifying 2-DE resolved proteins. Here we show how partial protein sequence data obtained by rapid peptide mapping, using capillary column liquid chromatography directly coupled with electrospray ionization tandem mass spectrometric methodologies, enhances the usefulness of this approach for identifying incompletely resolved proteins. The nonreducing 2-DE gel images reported in this study, along with our master 2-DE gel protein database for both normal human colonic crypts and several colon-cancer-derived cell lines, and information regarding microtechniques employed in this laboratory for obtaining structural data on 2-DE resolved proteins can be accessed over the Internet using World Wide Web (URL address: http:@www.ludwig.edu.au).
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PMID:Nonreducing two-dimensional polyacrylamide gel electrophoretic analysis of human colonic proteins. 749 56

To determine correlates of the geographic variation in colon cancer mortality within China, dietary variables, biochemical markers, and other factors from an ecological survey in 49 Chinese rural counties were examined. High consumption of animal foods, salt-preserved vegetables, and beer was associated with increased mortality of colon cancer, whereas the rates were significantly inversely related with intake of green vegetables. Serum levels of total cholesterol, urea nitrogen, and lipid peroxide were positively correlated with colon cancer mortality, after adjustment for each other and for other blood nutrients. No appreciable associations, however, were found between colon cancer and serum levels of beta-carotene, alpha-tocopherol, vitamin C, and selenium. In addition, prevalence of schistosomiasis was significantly correlated with increased colon cancer mortality. This ecological study indicates that observations from earlier analytic investigations in Western societies may apply to a Chinese rural population and suggests that schistosomiasis and dietary factors may contribute to the remarkable geographic variation of colon cancer in China.
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PMID:Correlations of colon cancer mortality with dietary factors, serum markers, and schistosomiasis in China. 841 26

The murine monoclonal antibody A33 (mAbA33) recognises a human cell membrane-associated antigen selectively expressed in epithelial cells of the lower gastrointestinal tract and > 90% of colonic cancers, but is not detected in a wide range of other normal tissues by immunohistochemical analysis. In phase I/II clinical triasl, mAbA33 has been shown to target advanced colon cancers and the humanized version is currently being evaluated in therapy studies. Although the mAbA33 has been well characterised by immunohistochemical and clinical studies, until recently, the target antigen has remained poorly defined. This was largely attributable to the antigenic determinant recognised by mAbA33 being dependent on the native spatial conformation of the A33 antigen which impeded its identification by conventional two-dimensional electrophoresis (2-DE) and immunoblot analysis. We have developed an immunoblot method, based on nonreducing/non-urea precast 2-DE gels, that has facilitated the purification of the detergent (0.3% Triton X-100) solubilised A33 antigen from the human colon cancer cell lines LIM1215 and SW1222. Under these 2-DE conditions, the A33 antigen electrophoreses with an apparent M(r) approximately 41000 and pI 5.0-6.0. Attempts to isolate the A33 antigen from 2-DE gels for direct structural analysis were unsuccessful, due to its co-electrophoresis with actin and cytokeratin proteins. However, using Western blot and biosensor detection the A33 antigen has been purified chromatographically and N-terminal sequence analysis was possible. Using polyclonal antibodies raised against a synthetic peptide corresponding to the N-terminal region of the A33 antigen we have used Western blot analysis to localise the molecule in our master 2-DE protein database for normal human colon crypts and several colon carcinoma cell lines (URL address: http:(/)/www.ludwig.edu.au). Under reducing 2-DE conditions, the A33 antigen electrophoresis as 6 differentially charged isoforms (pI 4.6-4.8) with a single molecular weight species at M(r) approximately 55000.
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PMID:Electrophoretic analysis of the novel antigen for the gastrointestinal-specific monoclonal antibody, A33. 915 Sep 49


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