Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0699790 (colon cancer)
 28,837 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The antineoplastic effect of heavy water on the growth of xenotransplanted human carcinoma was compared to that of 2 cytostatic drugs. Seven-week-old BALB/c-nu/nu mice were inoculated subcutaneously with a poorly differentiated oropharyngeal squamous-cell carcinoma, or with variants of carcinoma of the large intestine. After tumor inoculation, 3 subgroups of mice were treated by: (i) moderately deuterated drinking water; (ii) i.p. injections of 5-Fluoro-uracil (5-FU) or Bleomycin; (iii) a combination of deuterated drinking water and of the cytostatic drugs. Control mice were not treated. Heavy water delayed growth of all carcinoma variants. The cytostatic drugs slowed down the growth of the 2 poorly differentiated tumor variants. Conversely, 5-FU did not retard the growth of the moderately well differentiated colon carcinoma. Heavy water combined with either cytostatic drug showed synergistic effects in the 2 poorly differentiated tumor variants. The tumors of treated animals weighed 36% to 90% less than those of control animals. The antineoplastic effects were more conspicuous in poorly than in moderately well differentiated tumor variants. Cytokinetic parameters such as labelling indices following application of 5-125I-Iodo-2'deoxyuridine, and of Ki-67, a monoclonal antibody (MAb) directed against an antigen of proliferating cells, or mitotic indices and tumor volume doubling time, combined with the results of histologic evaluation of the tumors, suggested an underlying deuterium-induced prolongation of tumor-cell cycle times and a reduction of the growth fraction.
 ...
PMID:Heavy water enhances the antineoplastic effect of 5-fluoro-uracil and bleomycin in nude mice bearing human carcinoma. 168 3

The proposed intermediate steps in the relationship between a diet-dependent increase in colonic bile acids and proliferation of colonic cells were studied in rats. Male Wistar rats were fed diets supplemented with increasing amounts of steroids to increase the bile acid concentration of the colon. After 2 weeks, in vivo colonic proliferation was measured using tritiated thymidine incorporation into DNA. Luminal lytic activity was measured as lysis of erythrocytes by fecal water. To quantify hemolysis in the presence of fecal water, a method was developed which measures Fe-release using atomic absorption spectrophotometry. This method proved to be superior to the cell-counter method published earlier. Our results showed that steroid supplementation increased, in a dose-dependent manner, the total fecal and the soluble bile acid concentration as well as lytic activity of fecal water and colonic proliferation. A highly significant correlation between lytic activity of fecal water and colonic proliferation (r = 0.85, n = 24, P less than 0.001) was observed. These results indicate that the increase in colonic proliferation is mediated by diet-dependent increases in soluble colonic bile acid concentration and luminal lytic activity. This sequence of effects illustrates how diet could influence the risk for colon cancer.
 ...
PMID:Diet-induced increase of colonic bile acids stimulates lytic activity of fecal water and proliferation of colonic cells. 173 71

Diet is a major determinant of colon cancer risk. Calcium may protect against colon cancer, presumably by binding cytotoxic bile acids and fatty acids. Numerous studies support this proposition. In subjects at risk for colon cancer oral calcium supplementation has been shown to reduce rectal epithelial proliferation rate, thereby supposedly decreasing cancer risk. In contrast to the original hypothesis that phosphate counteracts the effect of calcium, evidence has now been provided that phosphate is crucial for the intraluminal binding of bile acids in complexes of calcium, phosphate, and bile acids. Supplemental calcium has been shown to reduce the cytotoxic potential of fecal water, which is probably attributable to the profound effect of calcium on bile acid and fatty acid metabolism. However, some reservation with regard to the protective ability of calcium seems to be warranted as we found that oral calcium supplementation caused an increase in epithelial proliferation rate in the sigmoid of patients with adenomatous polyps. Further controlled studies evaluating the effects of calcium on the epithelium of different parts of the colon should now be performed.
 ...
PMID:Calcium and the prevention of colon cancer. 177 41

Despite the links between low calcium (Ca) intake and age-related bone loss, hypertension, and colon cancer, the majority of Western populations have average daily Ca intakes substantially below recommended daily allowances. Although dietary products are widely known as a rich and valuable source of Ca in the diet, consumption of diary products is low and has been decreasing because of perceptions of excess calories and fat in the diet, as well as taste aversions. During the last decade, a marked increase in the consumption of bottled waters has occurred. Since some of these waters are characterized by high concentrations of Ca, we have studied Ca bioavailability from a Ca-rich water, using 15 lactose intolerant male individuals as subjects, and compared such bioavailability to that from milk. We report herein that the bioavailability of Ca from the water was generally as good as or better than that from milk, a food product well known for its very high Ca bioavailability. Indeed, in eight of 15 subjects, there was a higher level of Ca absorption from mineral water than from milk; bioavailability was equal in five of 15 subjects; in contrast, in two of 15 subjects, the bioavailability of Ca absorption from milk was greater than that from the mineral water. The potential implications of this observation for the prevention and management of age-related bone loss are important for preventive medicine and indicate a new, important source of dietary Ca for lactose intolerant individuals.
 ...
PMID:Comparative uptake of calcium from milk and a calcium-rich mineral water in lactose intolerant adults: implications for treatment of osteoporosis. 179 46

The biochemical and nutritional studies discussed here are consistent with the model presented in Figure 1. As shown in vitro, bile acids are precipitated by insoluble calcium phosphate. This calcium phosphate dependent precipitation drastically inhibits their cytotoxicity. A diet-induced increase in luminal surfactant concentration stimulates lytic activity of faecal water and intestinal cell damage resulting in an increased proliferation. The increase in luminal surfactant concentration and lytic activity of faecal water can be counteracted by supplemental dietary calcium phosphate. Supplemental calcium in humans increases the formation of insoluble calcium-phosphate-bile acid complexes in faeces, decreases the soluble fatty acid concentration and decreases lytic activity of faecal water. This sequence of effects offers a molecular explanation of the protective effects of supplemental calcium on proliferation as frequently observed (see studies cited above). It should be realised that this chain of evidence still lacks final proof of a preventive effect of dietary calcium on colorectal cancer. Until now, only protective effects on the first stage of development of colorectal cancer (hyperproliferation) have been observed. More well-designed studies in patients and healthy volunteers are needed using a combined biochemical, nutritional and clinical approach to elucidate the complex mechanism of the protective effect of calcium on colon cancer.
 ...
PMID:Calcium phosphate, bile acids and colorectal cancer. 184 34

Carrageenans are seaweed extracts comprising high molecular weight sulphated polygalactosides. They are used in foods at concentrations of up to 2.5% as thickening and gelling agents. When degraded to lower molecular weight forms, they have been shown to induce ulcerative colitis and colon cancer in laboratory animals. Furthermore, undegraded carrageenan (CG) has been shown to promote azoxymethane and methylnitrosourea initiated carcinogenesis, but the promotion mechanism is unclear. To determine if this mechanism involves alterations of tissue drug-metabolizing enzyme system (DMES) activities, six groups of five guinea-pigs each were administered 0.2% kappa undegraded, 0.2% i undegraded, 1% kappa degraded or 1% i degraded CG, or control solutions in the drinking-water for 8 wk. Microsomal and cytosolic DMES activities of the liver, small intestine and colon were determined. The kappa undegraded CG group exhibited significant (P less than 0.05) increases in small intestine cytochrome P-450 levels and benzo[a]pyrene hydroxylase activities. These data suggest that undegraded CG may selectively induce DMES activities in the small intestine mucosa.
 ...
PMID:The effects of carrageenan on drug-metabolizing enzyme system activities in the guinea-pig. 212 69

This investigation studied the effects of a shift from a mixed diet to a lactovegetarian diet on some cancer-associated bacterial enzymes in human feces (beta-glucuronidase, beta-glucosidase, and sulphatase). Three months after the shift to the lactovegetarian diet, there was a significant decrease in beta-glucuronidase, beta-glucosidase, and sulphatase activities per gram feces wet weight (p less than 0.05, less than 0.05, and less than 0.001, respectively). In contrast, glucuronide and glucoside hydrolysis remained unchanged per gram dry weight, although sulphatase activity was still significantly lowered when expressed this way (p less than 0.01). However, the fecal excretion increased significantly (p less than 0.05). Part of the explanation for the decreased enzyme activities is obviously a dilution effect, because much of the increased fecal weight after the shift in diet was associated with a higher water content. The higher water content was probably due to a higher fiber intake (p less than 0.001). Thus, the results in this paper indicate that a change from a mixed diet to a lactovegetarian diet leads to a decrease in certain enzyme activities proposed to be risk factors for colon cancer.
 ...
PMID:Shift from a mixed diet to a lactovegetarian diet: influence on some cancer-associated intestinal bacterial enzyme activities. 212 19

Evidence that physical activity may protect against various forms of cancer is examined in relation to occupational demands, leisure activities and participation in sport while at university. The variety of forms of neoplasm and equally varied physical activity histories militate against finding any simple relationship between the risk of malignancy and the individual's physical activity history. Nevertheless, five of seven major occupational studies suggest that a physically active occupation offers some protection against colon cancer, and an application of Bradford Hill's criteria generally supports the causal nature of the relationship between physical inactivity and an increased risk of intestinal neoplasia. However, existing reports are by no means conclusive; there thus remains a need for well-designed epidemiological studies of this issue. Data from one laboratory also suggest that in women a history of active leisure is associated with a reduced prevalence of breast and reproductive system cancers. Physical activity potentially encourages a healthy lifestyle, and it could have more direct effects on certain forms of carcinogenesis (for instance, by a speeding of gastro-intestinal transit, or a moderation of sex hormone levels). However, there are also potential negative effects from some types of exercise, particularly an excessive exposure to ultra-violet light in certain water sports. Since moderate exercise elevates mood and helps to conserve lean tissue, it may finally be a helpful component of treatment after a neoplasm has been diagnosed.
 ...
PMID:Physical activity and cancer. 228 78

Butyrate has induced differentiation in neoplastic cells grown in vitro, among them being colon cancer cell lines. In vivo, only one major study used sodium butyrate in the drinking water and showed an elevation in 1,2-dimethylhydrazine induced colon cancer in rats. Seeking to show that it was the sodium and not the butyrate which was responsible for the enhancement, we fed tributyrin at a 5% level to mice for 48 weeks. Mice experienced normal growth and development at this dose. Analysis of short chain fatty acids in the feces after 6 months in tributyrin feeding showed a 10-fold increase in butyric acid. However no difference in AOM induced focal areas of dysplasia or colonic tumor incidence was observed between tributyrin fed and control mice. At least two conclusions have been reached by this study, (1) that the dietary use of a sodium salt can contribute to the enhancement of chemically induced colon neoplasia and (2) butyrate may be discounted as providing any major therapeutic benefit against colonic tumorigenesis.
 ...
PMID:Dietary butyrate (tributyrin) does not enhance AOM-induced colon tumorigenesis. 235 22

In November 1985, the New York State Department of Health was altered to extraordinary concentrations of asbestos leachate in the drinking water in the Town of Woodstock. Concentrations of 3.2 million fibers per liter (MFL) to 304.5 MFL were found, depending on location. An investigation of cancer incidence in the area was conducted for the period 1973-83 using the State Cancer Registry to compute standardized incidence ratios. No evidence was found of elevated cancer incidence at sites associated with asbestos exposure. A statistically non-significant excess of kidney cancer was seen among men, but not women. Colon cancer among men was significantly low, but incidence among women was similar to that expected. Lung cancer incidence was lower than expected for both sexes. Ovarian cancer rates were not different from expected rates. At sites not previously related to asbestos exposure, cancer of the oral cavity was significantly high, with most affected persons having a history of cigarette smoking. Surveillance of the community is continuing because of an insufficient latent period for some exposed groups.
 ...
PMID:Cancer incidence following exposure to drinking water with asbestos leachate. 249 74


<< Previous 1 2 3 4 5 6 7 8 9 10 Next >>