La production fermière en France : actualités et enjeux

La vente de produits fermiers, transformés ou non, est une pratique ancienne et toujours d'actualité ; elle a su résister à la modernisation de l'agriculture et à une politique agricole productiviste. L'utilisation du terme "fermier" est réglementée par des textes différents selon les produits. La Loi d'Orientation Agricole de 1999 annonce l'élaboration d'un décret de portée générale. Les associations d'agriculteurs se regroupent pour soumettre au gouvernement des propositions. En 2000, 15.4 % des agriculteurs procèdent à la vente directe et 9.2 % transforment des produits pour la vente. Atout économique, concurrentiel et social pour le producteur, le produit fermier correspond aux attentes du consommateur qui recherche aujourd'hui des produits gastronomiques sains et naturels empreints de symbolique. Les consommateurs de produits fermiers sont proches de la moyenne nationale, un peu moins jeunes et plus aisés. Un tiers d'entre eux acceptent une majoration de prix de plus de 30 % par rapport aux produits standards. Le segment de marché des produits fermiers est en croissance et s'oriente vers le haut de gamme. Pour satisfaire les consommateurs, les producteurs deviennent désormais de vrais entrepreneurs : ils n'hésitent plus à innover en termes de gamme et modes de commercialisation. Les exemples des productions fermières laitière et porcine, plus ou moins bien implantées au sein des filières conventionnelles, montrent que l'activité fermière peut être rentable, créatrice d'emplois, et qu'elle suscite de nouvelles installations. Cependant de nombreuses contraintes réglementaires, notamment sanitaires subsistent. Des solutions collectives ont été proposées : le réseau "Bienvenue à la Ferme" de l'APCA et les cahiers des charges fermiers de la FNAPF. En outre, les Contrats Territoriaux d'Exploitation, outils de la nouvelle Loi d'Orientation Agricole, peuvent constituer un support utile pour développer des initiatives individuelles ou collectives

P2 receptors in atherosclerosis and postangioplasty restenosis

Atherosclerosis is an immunoinflammatory process that involves complex interactions between the vessel wall and blood components and is thought to be initiated by endothelial dysfunction [Ross (Nature 362:801–09, 1993); Fuster et al. (N Engl J Med 326:242–50, 1992); Davies and Woolf (Br Heart J 69:S3–S11, 1993)]. Extracellular nucleotides that are released from a variety of arterial and blood cells [Di Virgilio and Solini (Br J Pharmacol 135:831–42, 2002)] can bind to P2 receptors and modulate proliferation and migration of smooth muscle cells (SMC), which are known to be involved in intimal hyperplasia that accompanies atherosclerosis and postangioplasty restenosis [Lafont et al. (Circ Res 76:996–002, 1995)]. In addition, P2 receptors mediate many other functions including platelet aggregation, leukocyte adherence, and arterial vasomotricity. A direct pathological role of P2 receptors is reinforced by recent evidence showing that upregulation and activation of P2Y2 receptors in rabbit arteries mediates intimal hyperplasia [Seye et al. (Circulation 106:2720–726, 2002)]. In addition, upregulation of functional P2Y receptors also has been demonstrated in the basilar artery of the rat double-hemorrhage model [Carpenter et al. (Stroke 32:516–22, 2001)] and in coronary artery of diabetic dyslipidemic pigs [Hill et al. (J Vasc Res 38:432–43, 2001)]. It has been proposed that upregulation of P2Y receptors may be a potential diagnostic indicator for the early stages of atherosclerosis [Elmaleh et al. (Proc Natl Acad Sci U S A 95:691–95, 1998)]. Therefore, particular effort must be made to understand the consequences of nucleotide release from cells in the cardiovascular system and the subsequent effects of P2 nucleotide receptor activation in blood vessels, which may reveal novel therapeutic strategies for atherosclerosis and restenosis after angioplasty

Régulation de la fibrinolyse par l'endothélium vasculaire (aspects fondamentaux et thérapeutiques)

LYON1-BU Santé (693882101) / SudocRENNES1-BU Santé (352382103) / SudocSudocFranceF

La production fermière en France (actualités et enjeux)

TOULOUSE3-BU Santé-Centrale (315552105) / SudocTOULOUSE-EN Vétérinaire (315552301) / SudocSudocFranceF

Effet de l'exercice physique sur les différents mécanismes médiant la relaxation artérielle endothélium-dépendante (Approche in vivo et in vitro chez l'homme et l'animal)

La première cause de mortalité en France est la maladie cardiovasculaire. Le dysfonctionnement de l'endothélium vasculaire est la principale caractéristique de la maladie et entraîne un dérèglement du contrôle de la vasodilatation. De nombreuses études appuient la thèse que l'entraînement physique améliore la fonction de l'endothélium. Notre travail de recherche a démontré dans un premier temps que l'endothélium est l'une des composantes de la vasodilatation observée après hyperémie réactive chez le rat. Cette composante est mesurable au niveau de la microcirculation cutanée par Laser Doppler. Dans un deuxième temps nous avons mis en évidence chez des athlètes de haut niveau une potentialisation de la vasodilatation induite par l'hyperémie. Le même résultat est observé chez le rat à l'exercice. Enfin, nous nous sommes intéressés à l'optimisation de la fréquence d'exercice physique dans le cadre de la prévention cardiovasculaire. Une fréquence de 3-4 sessions par semaine semble être optimale. Les mécanismes médiant la vasodilatation endothélium-dépendante ont été explorés et les voies de la NO synthase, de la cyclooxygénase et de l'EDHF semblent toutes trois impliquésCardiovascular diseases are the leading causes of death in developed countries. A universal feature of cardiovascular diseases related to atherosclerosis is a dysfunction of the vascular endothelium. Regular chronic physical activity reduces cardiovascular risk. Numerous studies support the hypothesis that exercise training improves endothelial function. Our research work demonstrated at first that the endothelium is one of the constituents of the vasodilatation observed after reactive hyperemia to the rat. This constituent is measurable in the cutaneous microcirculation by Laser Doppler. Furthermore we have shown in high level athletes an improvement in the response to reactive probably mediated by endothelial function. The same result is observed in chronic physical exercise rats. Finally, we were interested in the optimization of the frequency of physical exercise within the framework of the cardiovascular prevention. A frequency of 3-4 sessions a week seems to be optimal. Mechanisms inducing endothelium-dependent vasodilatation were investigated and the pathways of NOS, COX and EDHF seem t be impliedBREST-BU Droit-Sciences-Sports (290192103) / SudocSudocFranceF

Effect of exercise training on cutaneous microcirculation in rats.

International audienceAIM: Exercise training is known to improve endothelium-dependent relaxation in the coronary and skeletal muscle arteries. However, the effects of exercise training on peripheral nonworking tissue, including microcirculation, are still unclear. Therefore, we investigated the effect of chronic and regular aerobic exercise on cutaneous microvascular endothelial function in rats. METHODS: We assessed the effect of physical training on skin microcirculation in 7 sedentary (SED) and 21 training rats (Wistar-Kyoto), submitted to a treadmill training protocol (15 m/min; 15% incline; 60 min/day; 8 weeks). Training rats were divided into 3 groups, exercising 1 day/week (Ex1), 3 days/week (Ex3) or 5 days/week (Ex5). Cutaneous blood flow was recorded before the beginning of the training protocol, after 4 weeks and at the end of the training program. Hyperemic response (RH) was the flow reaction obtained after sudden release of the garrot. For data analysis, cutaneous vascular conductance (CVC) was indexed as cutaneous blood flow divided by mean arterial blood pressure (in millimeters of mercury, mmHg) and normalized to baseline values. RESULTS: At baseline, CVC was not different among groups (SED or training) at 3 steps of experimental protocol. The hyperemic stimulus significantly increased normalized CVC only in group Ex3 after 4 weeks (P<0.006) and 8 weeks (P<0.006). CONCLUSION: Exercise training exerts a generalized effect on the vasculature by increasing endothelial function in vessel beds different from those perfusing actively working muscle. However, some differences exist since training at a frequency of 3 bouts weekly only modifies cutaneous microcirculation

Effect of training frequency on endothelium-dependent vasorelaxation in rats.

International audienceBACKGROUND: Moderate physical activity enhances endothelium-dependent vasorelaxation. Whether the frequency of exercise affects endothelial function is unclear. The purpose of this study was to investigate the effects of various frequencies of training on endothelium-dependent vasorelaxation. DESIGN: Male Wistar rats were trained for 8 weeks on a treadmill at various frequencies [1 (Ex1), 3 (Ex3) or 5 days/week (Ex5)] and compared with age-matched sedentary animals (SED). A control group allowed us to assess endothelial function before the exercise protocol. Rings of thoracic aorta were precontracted with phenylephrine. RESULTS: Endothelium-independent relaxation elicited by sodium nitroprusside was similar in all groups. The maximal response elicited by acetylcholine (ACh) was not different between groups, whereas pD2 values (-logEC50, EC50 being the concentration of ACh that elicited 50% of the maximal response) significantly correlated with frequency of training. nitro-L-arginine methyl ester (L-NAME) reduced the relaxation elicited by 10(-7) mol/l ACh or higher in control and all trained groups, and by 10(-6) mol/l ACh or higher in SED group. Indomethacin inhibited the vasodilating response to 10(-7) mol/l ACh or higher in control, SED and Ex1 groups, and to 10(-8) mol/l or more in Ex3 and Ex5 animals. Tetraethylammonium attenuated the response to 10(-6) mol/l ACh or higher in control and SED groups and to 10(-7) mol/l or more in all trained animals. CONCLUSION: This data suggest that decreased ACh-induced vasorelaxation after physical inactivity may result from impairment of endothelial nitric oxide synthase, prostacyclin and endothelium-derived hyperpolarizing factor pathways. This effect is prevented by training in a frequency-dependent manner

Reactive hyperaemia in the forearm skin of highly trained windsurfers.

International audienceWe undertook this study to determine whether long-term high intensity exercise would modify cutaneous endothelial-dependent vasodilation. We compared a group of 9 highly trained windsurfers (mean age: 24.5 +/- 1.6 years) to a control group of 8 sedentary individuals (22.9 +/- 0.4 years, NS). Laser Doppler was used to measure cutaneous blood flow in the resting state (baseline), during post-occlusive hyperaemia (endothelium-dependent vasodilation), and local heating to 42 degrees C. Lipid profile was similar in both groups. Resting heart rate was significantly lower in windsurfers. Baseline cutaneous vascular conductance (CVC) values were similar in both groups (0.059 +/- 0.016 and 0.051 +/- 0.009). During reactive hyperaemia, normalized peak CVC value was significantly higher in the windsurfers group (1775.4 +/- 286.9 and 826.4 +/- 121.7 % baseline CVC; p = 0.01). Normalized peak CVC value in response to local heating (42 degrees C) was not significantly different between both groups (2359.4 +/- 346.1 and 1467.7 +/- 282.6 % baseline CVC). Endothelium-dependent vasodilation in cutaneous microcirculation is significantly enhanced in the forearm skin of highly trained windsurfers when compared to sedentary controls