The application of multiplex fluorimetric sensor for the analysis of flavonoids content in the medicinal herbs family Asteraceae, Lamiaceae, Rosaceae

BACKGROUND: The aim of our research work was to quantify total flavonoid contents in the leaves of 13 plant species family Asteraceae, 8 representatives of family Lamiaceae and 9 plant species belonging to familyRosaceae, using the multiplex fluorimetric sensor. Fluorescence was measured using optical fluorescence apparatus Multiplex(R) 3 (Force-A, France) for non-destructive flavonoids estimation. The content of total flavonoids was estimated by FLAV index (expressed in relative units), that is deduced from flavonoids UV absorbing properties. RESULTS: Among observed plant species, the highest amount of total flavonoids has been found in leaves ofHelianthus multiflorus (1.65 RU) and Echinops ritro (1.27 RU), Rudbeckia fulgida (1.13 RU) belonging to the family Asteraceae. Lowest flavonoid content has been observed in the leaves of marigold (Calendula officinalis) (0.14 RU) also belonging to family Asteraceae. The highest content of flavonoids among experimental plants of family Rosaceae has been estimated in the leaves of Rosa canina (1.18 RU) and among plant species of family Lamiaceae in the leaves of Coleus blumei (0.90 RU). CONCLUSIONS: This research work was done as pre-screening of flavonoids content in the leaves of plant species belonging to family Asteraceae, Lamiaceae and Rosaceae. Results indicated that statistically significant differences (P > 0.05) in flavonoids content were observed not only between families, but also among individual plant species within one family.

Anestesia, demencias y enfermedad de Alzheimer: ¿coincidencia o certeza? / Anesthesia, dementia and Alzheimer's disease: coincidence or certainty?

Existe creciente evidencia derivada de modelos experimentales in vitro, cultivos celulares y modelos animales que sugiere el efecto de la anestesia sobre la degeneración neuronal y una interacción entre la cirugía, la anestesia y la neuropatología denominada Alzheimer. También existe la firme creencia de que los ancianos corren el riesgo de sufrir deterioro cognitivo transitorio, aunque también puede ser persistente, después de haber sido sometidos a una cirugía mayor, y ese deterioro puede estar asociado a muerte o debilidad. En este trabajo revisamos brevemente los fundamentos básicos de la enfermedad de Alzheimer y su interacción con la anestesia general, y los pocos datos clínicos en humanos que han sido utilizados para proponer una posible asociación entre la anestesia general y las demencias.

Regulatory roles of microtubule-associated proteins in neuronal morphogenesis. Involvement of the extracellular matrix

As a result of recent investigations, the cytoskeleton can be viewed as a cytoplasmic system of interconnected filaments with three major integrative levels: self-assembling macromolecules, filamentous polymers, e.g., microtubules, intermediate filaments and actin filaments, and supramolecular structures formed by bundles of these filaments or networks resulting from cross-bridges between these major cytoskeletal polymers. The organization of this biological structure appears to be sensitive to fine spatially and temporally dependent regulatory signals. In differentiating neurons, regulation of cytoskeleton organization is particularly relevant, and the microtubule-associated protein (MAP) tau appears to play roles in the extension of large neuritic processes and axons as well as in the stabilization of microtubular polymers along these processes. Within this context, tau is directly involved in defining neuronal polarity as well as in the generation of neuronal growth cones. There is increasing evidence that elements of the extracellular matrix contribute to the control of cytoskeleton organization in differentiating neurons, and that these regulations could be mediated by changes in MAP activity. In this brief review, we discuss the possible roles of tau in mediating the effects of extracellular matrix components on the internal cytoskeletal arrays and its organization in growing neurons

Functional organization of tau proteins during neuronal differentiation and development

Tau proteins play major regulatory roles in the organization and integrity of the cystoskeletal networks. In neurons, a specific axonal compartmentalization of tau has been shown. However, recent studies demonstrate that tau displays a widespread distribution in a variety of non-neuronal cell types. These proteins have been found in human fibroblasts and in several transformed cell lines. The heterogenous family of tau is formed by a set of molecular species that share common peptide sequences. There is a single gene that contains several exons enconding for the six different tau isoforms in mammalian brain. Alternative splicing of a common RNA transcript as well as post-translational modifications contribute to its heterogeneity. Tau isoforms generated by splicing differ from one another by having either three or four repeats in their C-terminal half, and a variable number of inserts in their N-terminal moiety. These repeats have been shown to constitute microtubule-binding motifs. In this review some relevant aspects of tau function and its regulation are analysed. Three major topics are discussed. The first one focuses on the tau roles in regulating the interactions between microtubules with actin filaments and with intermediate filment systems. Another problem deals with the question of whether tau isoforms segregate into functionally different subsets of microtubules in axonal processes, or tau associates with these polymers in a random fashion. The third question that emerges is the involvement of tau and tau-like proteins in morphogenetic events. The regulation of the interactions of DMAP-85, a recently discovered tau-like protein, with the cytoskeleton during development of Drosophila melanogaster is analyzed.

La enfermedad de Alzheimer y el rol de la apolipoproteina E / Alzheimer's disease and the role of apolipoprotein E

La enfermedad de Alzheimer (EA) es una tendencia progresiva que afecta al adulto mayor y cuyas lesiones características son: las placas seniles, los ovillos neurofibrilares y los depósitos vasculares de amiloide. Uno de los componentes principales de las placas seniles es el péptido beta-amiloide (A4), cuya proteína precursora esta codificada en el cromosoma 21. La EA además está relacionada con los cromosomas 14 y 19. En este último se encuentra el gen de la poliproteína E (apoE). La apoE es una proteína de gran importancia en el sistema nervioso, que también se encuentra en las tres lesiones características de la EA. Parte de su función se relaciona con la reparación neuronal, debido a su capacidad de transportar lípidos a los sitios de regeneración. Existen 3 alelos para la apoE, el e2, el e3 y el e4, siendo el alelo e3 el más frecuente en la población mundial. Interesantemente, existe una correlación positiva entre el alelo e4 de la apoE y la EA, constituyendo este alelo un factor de riesgo para la enfermedad. Esta y otras evidencias han llevado apostular diversas hipótesis acerca de la participación de la apoE en el desarrollo de la EA. Una de ellas se refiere a la interacción entre la apoE4 y el péptido A4, la cual conduciría a la formación de las placas neuríticas. Alternativamente, se postula un papel para la apoE en la formación de los ovillos neurofibrilares. Finalmente, se considera el daño neuronal como un factor de riesgo adicional para la EA, en el que se vería favorecido el encuentro entre la apoE y el A4, con el consiguiente mayor depósito de amiloide en las placas neuríticas