Cœur arraché / Cœur mangé : modulations

La présente étude rassemble des textes qui, à travers genres et siècles (du Moyen Âge au XVIIe ; de l'épopée au roman et à la nouvelle), sont liés par le jeu de motifs spécifiques gravitant autour de l'image violente du " cœur arraché " et " mangé ". Ces motifs, relevant de la signification symbolique des rites funéraires du temps, servent à renforcer un ensemble de valeurs politico-sociales (honneur, fidélité, loyauté) qui sont favorables au maintien de la bonne ordonnance de la communauté de chaque époque. L'horreur des actes décrits et les conséquences qui en découlent devaient assurer dans les esprits l'empreinte d'une leçon salutaire et profonde.The present article assembles several texts which, from the Middle Ages to the 17th century and from the Old French epic to the romance and the novella, are linked by a series of specific motifs to the violent epic image of the " torn out heart " and the famous medieval image of the " eaten heart ". These motifs, grafted on the symbolic meaning of funeral rituals, reinforce politico-social values, such as honor, fidelity, loyalty, that maintain order in the community of each period. The horrifying acts and their consequences must have impress a good and salutary lesson on the mind of the reader

Beef meat promotion of dimethylhydrazine-induced colorectal carcinogenesis biomarkers is suppressed by dietary calcium

Red meat consumption is associated with increased risk of colorectal cancer. We have previously shown that haemin, Hb and red meat promote carcinogen-induced preneoplastic lesions: aberrant crypt foci (ACF) and mucin-depleted foci (MDF) in rats. We have also shown that dietary calcium, antioxidant mix and olive oil inhibit haemin-induced ACF promotion, and normalize faecal lipoperoxides and cytotoxicity. Here we tested if these strategies are effective also against red meat promotion in dimethylhydrazine-induced rats. Three diets with 60% beef meat were supplemented with calcium phosphate (33 g/kg), antioxidant agents (rutin and butylated hydroxyanisole, 0•05% each) and olive oil (5 %). ACF, MDF, faecal water cytotoxicity, thiobarbituric acid reactive substances (TBARS) and urinary 1,4-dihydroxynonane mercapturic acid (DHN-MA) were measured. Beef meat diet increased the number of ACF (þ30 %) and MDF (þ100 %) (P,0•001), which confirms our previous findings. Promotion was associated with increased faecal water TBARs ( £ 4) and cytotoxicity ( £ 2), and urinary DHN-MA excretion ( £ 15). Calcium fully inhibited beef meat-induced ACF and MDF promotion, and normalized faecal TBARS and cytotoxicity, but did not reduce urinary DHN-MA. Unexpectedly, high-calcium control diet-fed rats had more MDF and ACF in the colon than low-calcium control diet-fed rats. Antioxidant mix and olive oil did not normalize beef meat promotion nor biochemical factors. The results confirm that haem causes promotion of colon carcinogenesis by red meat. They suggest that calcium can reduce colorectal cancer risk in meat-eaters. The results support the concept that toxicity associated with the excess of a useful nutrient may be prevented by another nutrient

toxines et signalisation

Collection Rencontres en toxinologie ISSN: 1760-6004 ; http://sfet.asso.fr/images/stories/SFET/pdf/EBook-RT17-2009-signets.pdfInternational audienc

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

Meat processing and colon carcinogenesis: Cooked, nitrite-treated and oxidized high-heme cured meat promotes mucin depleted foci in rats

Processed meat intake is associated with colorectal cancer risk, but no experimental study supports the epidemiologic evidence. To study the effect of meat processing on carcinogenesis promotion, we first did a 14-day study with 16 models of cured meat. Studied factors, in a 2 × 2 × 2 × 2 design, were muscle color (a proxy for heme level), processing temperature, added nitrite, and packaging. Fischer 344 rats were fed these 16 diets, and we evaluated fecal and urinary fat oxidation and cytotoxicity, three biomarkers of heme-induced carcinogenesis promotion. A principal component analysis allowed for selection of four cured meats for inclusion into a promotion study. These selected diets were given for 100 days to rats pretreated with 1,2-dimethylhydrazine. Colons were scored for preneoplastic lesions: aberrant crypt foci (ACF) and mucin-depleted foci (MDF). Cured meat diets significantly increased the number of ACF/colon compared with a no-meat control diet (P = 0.002). Only the cooked nitrite-treated and oxidized high heme meat significantly increased the fecal level of apparent total N-nitroso compounds (ATNC) and the number of MDF per colon compared with the no-meat control diet (P < 0.05). This nitrite-treated and oxidized cured meat specifically increased the MDF number compared with similar non nitrite-treated meat (P = 0.03) and with similar non oxidized meat (P = 0.004). Thus, a model cured meat, similar to ham stored aerobically, increased the number of preneoplastic lesions, which suggests colon carcinogenesis promotion. Nitrite treatment and oxidation increased this promoting effect, which was linked with increased fecal ATNC level. This study could lead to process modifications to make non promoting processed meat

Componentising a scientific application for the grid

CoreGRID is a Network of Excellence funded by the European Commission under the Sixth Framework Programm

Diferenciación genética de poblaciones atlánticas de charcos de marea del copépodo intermareal Tigriopus brevicornis

The Harpacticoid copepod Tigriopus brevicornis belongs to the meiofauna of intertidal rock pools and is distributed widely along European coasts. Sixteen sites were sampled from the Irish Sea to the coasts of Spain. We used the ITS1 marker to analyse the relationship between the populations because it shows low intrapopulational variation (mean pairwise difference: 1.00 ± 0.8) and high interpopulational divergence (mean pairwise difference: 16.38 ± 7.39). A total of 57 bp out of 433 bp were recognised as informative nucleotides among the 61 individuals analysed. The analysis of the genetic relationships highlighted a north-south split in the distribution of the natural populations and showed a genetic break point around the Gironde estuary, which is probably due to differences in the geomorphologic characteristics of the coastal area on the two different sides of this estuary. Various populations were isolated and the ITS1 sequences indicated that there are specific genetic signatures in these populations. The northern set of populations, which was sampled along a large rocky coastline, had a metapopulation structure with genetic exchanges between geographically close populations and also between geographically far ones. The southern set of populations, which was sampled in small rocky pools on large sandy beaches, showed isolated populations as a consequence of the geomorphology of the area.Los copépodos harpacticoides Tigriopus brevicornis pertenecen a la meiofauna intermareal y están ampliamente distribuídos a lo largo de las costas europeas. Dieciséis lugares fueron muestreados desde el Mar de Irlanda hasta las costas de España. Nosotros usamos el marcador ITSI para analizar la relación entre poblaciones porque se mostró una variación interpoblacional baja (promedio diferencia de pares: 1.00 ± 0.8) y una divergencia interpoblacional alta (promedio diferencia de pares: 16.38 ± 7.39). Un total de 57 bp entre 433 bp fueron reconocidos como nucleótidos informativos entre los 61 individuos analizados. El análisis de relación genética resalta una partición Norte-Sur en la distribución de las poblaciones naturales y mostraba un punto de rotura genético alrededor del estuario de Gironde, probablemente debido a las diferencias en las características geomorfológicas de esta área costera en ambos lados del estuario. Algunas poblaciones fueron aisladas: las secuencias ITSI indicaban que había unas señales genéticas específicas en estas poblaciones. La población de la parte norte, que fue muestreada a lo largo de una línea rocosa de costa, evidencia la estructura de una metapoblación con intercambios genéticos entre poblaciones geográficamente próximas, pero también entre poblaciones geográficamente lejanas. La población de la parte sur, que fue muestreada en pequeños charcos de marea sobre vastas playas arenosas, mostraban poblaciones aisladas, destacando las consecuencias de la geomorfología del área

Erythropoietin Down-Regulates Stem Cell Factor Receptor (Kit) Expression in the Leukemic Proerythroblast: Role of Lyn Kinase

Overexpression of the transcription factor Spi-1/PU.1 by transgenesis in mice induces a maturation arrest at the proerythroblastic stage of differentiation. We have previously isolated a panel of spi-1 transgenic erythroleukemic cell lines that proliferated in the presence of either erythropoietin (Epo) or stem cell factor (SCF). Using these cell lines, we observed that EpoR stimulation by Epo down-regulated expression of the SCF receptor Kit and induced expression of the Src kinase Lyn. Furthermore, enforced expression of Lyn in the cell lines increased cell proliferation in response to Epo, but reduced cell growth in response to SCF in accordance with Lyn ability to down-regulate Kit expression. Together, the data suggest that Epo-R/Lyn signaling pathway is essential for extinction of SCF signaling leading the proerythroblast to strict Epo dependency. These results highlight a new role for Lyn as an effector of EpoR in controlling Kit expression. They suggest that Lyn may play a central role in during erythroid differentiation at the switch between proliferation and maturation