Carnosine (beta-alanyl-L-histidine) and carcinine (beta-alanylhistamine) are natural imidazole-containing compounds found in the non-protein fraction of mammalian tissues. Carcinine was synthesized by an original procedure and characterized. Both carnosine and carcinine (10-25 mM) are capable of inhibiting the catalysis of linoleic acid and phosphatidylcholine liposomal peroxidation (LPO) by the O2(-.)-dependent iron-ascorbate and lipid-peroxyl-radical-generating linoleic acid 13-monohydroperoxide (LOOH)-activated haemoglobin systems, as measured by thiobarbituric-acid-reactive substance. Carcinine and carnosine are good scavengers of OH. radicals, as detected by iron-dependent radical damage to the sugar deoxyribose. This suggests that carnosine and carcinine are able to scavenge free radicals or donate hydrogen ions. The iodometric, conjugated diene and t.l.c. assessments of lipid hydroperoxides (13-monohydroperoxide linoleic acid and phosphatidylcholine hydroperoxide) showed their efficient reduction and deactivation by carnosine and carcinine (10-25 mM) in the liberated and bound-to-artificial-bilayer states. This suggests that the peroxidase activity exceeded that susceptible to direct reduction with glutathione peroxidase. Imidazole, solutions of beta-alanine, or their mixtures with peptide moieties did not show antioxidant potential. Free L-histidine and especially histamine stimulated iron (II) salt-dependent LPO. Due to the combination of weak metal chelating (abolished by EDTA), OH. and lipid peroxyl radicals scavenging, reducing activities to liberated fatty acid and phospholipid hydroperoxides, carnosine and carcinine appear to be physiological antioxidants able to efficiently protect the lipid phase of biological membranes and aqueous environments.

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<p>Cet essai analyse des poèmes fondateurs de la pensée du cubain José Lezama Lima en relation avec les arts, les religions et les philosophies qui gouvernent le monde. Ces études permettent de mettre en valeur le système poétique de José Lezama Lima.</p>

No hay resúmenes disponiblesRealidad: Revista de Ciencias Sociales y Humanidades No. 89, 2002: 675-683

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Entre tradiciones y procesos de transformación, asistimos a una poética del pensar del poema extenso en las Antillas hispanas. Desde la “décima”, venida de Europa, se desarrolla una creatividad lingüística por medio de una apertura pragmática, en estrecha relación con la particularidad colonial: entre mito del progreso y mito de la edad de oro. Para entender la inventiva caribeña, recordamos la práctica del Neobarroco, elaborado a base de las confluencias de lo heterogéneo. Vemos como a través de una heteroglosia discursiva, el poema extenso se asienta en este espacio cultural que son las islas antillanas y subrayamos su papel actual en el relato de historias mínimas que alimentan por otro cariz la historia universal.