New Marker of Colon Cancer Risk Associated with Heme Intake: 1,4-Dihydroxynonane Mercapturic Acid

Background: Red meat consumption is associated with an increased risk of colon cancer. Animal studies show that heme, found in red meat, promotes preneoplastic lesions in the colon, probably due to the oxidative properties of this compound. End products of lipid peroxidation, such as 4-hydroxynonenal metabolites or 8-iso-prostaglandin-F2 (8-iso-PGF2), could reflect this oxidative process and could be used as biomarkers of colon cancer risk associated with heme intake. Methods: We measured urinary excretion of 8-iso-PGF2 and 1,4-dihydroxynonane mercapturic acid (DHN-MA), the major urinary metabolite of 4-hydroxynonenal, in three studies. In a short-term and a carcinogenesis long-term animal study, we fed rats four different diets (control, chicken, beef, and blood sausage as a high heme diet). In a randomized crossover human study, four different diets were fed (a 60 g/d red meat baseline diet, 120 g/d red meat, baseline diet supplemented with heme iron, and baseline diet supplemented with non-heme iron). Results: DHN-MA excretion increased dramatically in rats fed high heme diets, and the excretion paralleled the number of preneoplastic lesions in azoxymethane initiated rats (P < 0.0001). In the human study, the heme supplemented diet resulted in a 2-fold increase in DHN-MA (P < 0.001). Urinary 8-iso-PGF2 increased moderately in rats fed a high heme diet (P < 0.0001), but not in humans. Conclusion: Urinary DHN-MA is a useful noninvasive biomarker for determining the risk of preneoplastic lesions associated with heme iron consumption and should be further investigated as a potential biomarker of colon cancer risk. (Cancer Epidemiol Biomarkers Prev 2006;15(11):2274–9

Growth arrest and cell death induced by the dietary anticarcinogen sulforaphane in human renal cancer cells are maintained after it was conjugated to glutathione

Various epidemiological studies have revealed an inverse association between renal cancer and consumption of cruciferous vegetables. Sulforaphane, a natural microconstituant from broccoli, has been shown to exert potent anti-tumoral properties in vitro as well as in vivo against colon and mammary chemically-induced tumors. Here, we show in human renal carcinoma cells ACHN cells, that conjugation of sulforaphane to glutathione, a process mainly responsible for its accumulation invarious cells, did not change the properties of this isothiocyanate (i.e. cell death, cell cycle arrest inthe S-phase and cyclin A and B1 induced-expression). This result constitutes a good support to possible protective properties against renal cancer described for cruciferous vegetables. Second, our finding seems to be in agreement with the previously described activation of compounds by conjugation to GSH. This may have important implications especially in explaining the effects of rapidly conjugated compounds on tissues and organs distant from the original site of exposure and/or conjugation

Chloromethane formation and degradation in the fern phyllosphere

International audienceChloromethane (CH3Cl) is the most abundant halogenated trace gas in the atmosphere. It plays an important role in natural stratospheric ozone destruction. Current estimates of the global CH3Cl budget are approximate. The strength of the CH3Cl global sink by microbial degradation in soils and plants is under discussion. Some plants, particularly ferns, have been identified as substantial emitters of CH3Cl. Their ability to degrade CH3Cl remains uncertain. In this study, we investigated the potential of leaves from 3 abundant ferns (Osmunda regalis, Cyathea cooperi, Dryopteris filix-mas) to produce and degrade CH3Cl by measuring their production and consumption rates and their stable carbon and hydrogen isotope signatures. Investigated ferns are able to degrade CH3Cl at rates from 2.1 to 17 and 0.3 to 0.9 μg gdw−1 day−1 for C. cooperi and D. filix-mas respectively, depending on CH3Cl supplementation and temperature. The stable carbon isotope enrichment factor of remaining CH3Cl was −39 ± 13‰, whereas negligible isotope fractionation was observed for hydrogen (−8 ± 19‰). In contrast, O. regalis did not consume CH3Cl, but produced it at rates ranging from 0.6 to 128 μg gdw−1 day−1, with stable isotope values of −97 ± 8‰ for carbon and −202 ± 10‰ for hydrogen, respectively. Even though the 3 ferns showed clearly different formation and consumption patterns, their leaf-associated bacterial diversity was not notably different. Moreover, we did not detect genes associated with the only known chloromethane utilization pathway “cmu” in the microbial phyllosphere of the investigated ferns. Our study suggests that still unknown CH3Cl biodegradation processes on plants play an important role in global cycling of atmospheric CH3Cl

Les précieuses ridicules : extraits / Molière, aut ; Maurice Jarre, comp. ; Lucien Arnaud, Yves Gasc, Danièle Girard... [et al.], voix parlée

Collection : Théâtre national populaireCollection : Théâtre national populaireComprend : Il est bien nécessaire, vraiment, de faire tant de dépense pour vous graisser le museau !... : scène IV - Mesdames, vous serez surprises, sans doute, de l'audace de ma visite... : scène IXBnF-Partenariats, Collection sonore - BelieveContient une table des matière