Inhibition of Fried Meat-Induced Colorectal DNA Damage and Altered Systemic Genotoxicity in Humans by Crucifera, Chlorophyllin, and Yogurt

Dietary exposures implicated as reducing or causing risk for colorectal cancer may reduce or cause DNA damage in colon tissue; however, no one has assessed this hypothesis directly in humans. Thus, we enrolled 16 healthy volunteers in a 4-week controlled feeding study where 8 subjects were randomly assigned to dietary regimens containing meat cooked at either low (100°C) or high temperature (250°C), each for 2 weeks in a crossover design. The other 8 subjects were randomly assigned to dietary regimens containing the high-temperature meat diet alone or in combination with 3 putative mutagen inhibitors: cruciferous vegetables, yogurt, and chlorophyllin tablets, also in a crossover design. Subjects were nonsmokers, at least 18 years old, and not currently taking prescription drugs or antibiotics. We used the Salmonella assay to analyze the meat, urine, and feces for mutagenicity, and the comet assay to analyze rectal biopsies and peripheral blood lymphocytes for DNA damage. Low-temperature meat had undetectable levels of heterocyclic amines (HCAs) and was not mutagenic, whereas high-temperature meat had high HCA levels and was highly mutagenic. The high-temperature meat diet increased the mutagenicity of hydrolyzed urine and feces compared to the low-temperature meat diet. The mutagenicity of hydrolyzed urine was increased nearly twofold by the inhibitor diet, indicating that the inhibitors enhanced conjugation. Inhibitors decreased significantly the mutagenicity of un-hydrolyzed and hydrolyzed feces. The diets did not alter the levels of DNA damage in non-target white blood cells, but the inhibitor diet decreased nearly twofold the DNA damage in target colorectal cells. To our knowledge, this is the first demonstration that dietary factors can reduce DNA damage in the target tissue of fried-meat associated carcinogenesis.ClinicalTrials.gov NCT00340743

Probing the Interstellar Medium in Early type galaxies with ISO observations

Four IRAS-detected early type galaxies were observed with ISO. With the exception of the 15 micron image of NGC1052, the mid-IR emission from NGC1052, NGC1155, NGC5866 and NGC6958 at 4.5, 7 and 15 microns show extended emission. Mid-IR emission from NGC1052, NGC1155, and NGC6958 follows a de Vaucouleurs profile. The ratio of 15/7 micron flux decreases with radius in these galaxies, approaching the values empirically observed for purely stellar systems. In NGC5866, the 7 and 15 micron emission is concentrated in the edge-on dust lane. All the galaxies are detected in the [CII] line, and the S0s NGC1155 and NGC5866 are detected in the [OI] line as well. The ISO-LWS observations of the [CII] line are more sensitive measures of cool, neutral ISM than HI and CO by about a factor of 10-100. Three of four early type galaxies, namely NGC1052, NGC6958 and NGC5866, have low ratio FIR/Blue and show a lower [CII]/FIR, which is due to a softer radiation field from old stellar populations. The low [CII]/CO ratio in NGC5866 ([CII]/CO(1-0) < 570) confirms this scenario. We estimate the UV radiation expected from the old stellar populations in these galaxies and compare it to that needed to heat the gas to account for the cooling observed [CII] and [OI] lines. In three out of four galaxies, NGC1052, NGC5866 and NGC6958, the predicted UV radiation falls short by a factor of 2-3. In view of the observed intrinsic scatter in the "UV-upturn" in elliptical galaxies and its great sensitivity to age and metallicity effects, this is not significant. However, the much larger difference (about a factor of 20) between the UV radiation from old stars and that needed to produce the FIR lines for NGC 1155 is strong evidence for the presence of young stars, in NGC1155.Comment: To appear in the Astrophysical Journal. Figure 1 appears as a separate jpg figur

Low colonic glutathione detoxification capacity in patients at risk for colon cancer.

Contains fulltext : 50669.pdf (publisher's version ) (Closed access)BACKGROUND: Colon carcinogenesis is a multifactorial process influenced by hereditary as well as environmental factors. The glutathione/glutathione S-transferase detoxification system in the colon is important for protection against carcinogens. We investigated the levels of glutathione/glutathione S-transferase in normal colon mucosa of patients with colorectal cancer and in patients at high risk for colorectal cancer compared with those in healthy controls. MATERIALS AND METHODS: Glutathione content was analyzed by high-performance liquid chromatography, and glutathione S-transferase enzyme activity by spectrophotometric determination with 1-chloro 2,4-dinitrobenzene. Normal colon tissue of patients with colon adenoma (n = 64), colorectal cancer (n = 37), familial adenomatous polyposis (FAP; n = 19), hereditary non-polyposis colorectal cancer families with (HNPCC+Ad; n = 34) or without (HNPCC-Ad; n = 33) adenoma was investigated. RESULTS: Glutathione levels were significantly lower in the normal colon mucosa of patients with cancer, FAP, HNPCC-Ad or HNPCC+Ad compared with adenoma patients or healthy controls. Glutathione S-transferase enzyme activity in the distal colon was significantly lower in patients with cancer or FAP compared with the adenoma patients or healthy controls, whereas values in carcinoma patients were significantly lower compared with both the HNPCC-Ad and HNPCC+Ad groups. CONCLUSIONS: An association of low colonic glutathione/glutathione S-transferase activity levels and high clinical risk for the development of colorectal cancer was observed. This low glutathione detoxification capacity might contribute to the colon cancer risk