The Selective 5-HT(6) Receptor Antagonist Ro4368554 Restores Memory Performance in Cholinergic and Serotonergic Models of Memory Deficiency in the Rat

Antagonists at serotonin type 6 (5-HT(6)) receptors show activity in models of learning and memory. Although the underlying mechanism(s) are not well understood, these effects may involve an increase in acetylcholine (ACh) levels. The present study sought to characterize the cognitive-enhancing effects of the 5-HT(6) antagonist Ro4368554 (3-benzenesulfonyl-7-(4-methyl-piperazin-1-yl)1H-indole) in a rat object recognition task employing a cholinergic (scopolamine pretreatment) and a serotonergic- (tryptophan (TRP) depletion) deficient model, and compared its pattern of action with that of the acetylcholinesterase inhibitor metrifonate. Initial testing in a time-dependent forgetting task employing a 24-h delay between training and testing showed that metrifonate improved object recognition (at 10 and 30 mg/kg, p.o.), whereas Ro4368554 was inactive. Both, Ro4368554 (3 and 10 mg/kg, intraperitoneally (i.p.)) and metrifonate (10 mg/kg, p.o., respectively) reversed memory deficits induced by scopolamine and TRP depletion (10 mg/kg, i.p., and 3 mg/kg, p.o., respectively). In conclusion, although Ro4368554 did not improve a time-related retention deficit, it reversed a cholinergic and a serotonergic memory deficit, suggesting that both mechanisms may be involved in the facilitation of object memory by Ro4368554 and, possibly, other 5-HT(6) receptor antagonists.Neuropsychopharmacology advance online publication, 15 June 2005; doi:10.1038/sj.npp.1300777

Layer-by-layer assembly for biofunctionalization of cellulosic fibers with emergent antimicrobial agents

Series title: Advances in polymer science series, ISSN 0065-3195, vol. 271Coating with polyelectrolyte multilayers has become a generic way to functionalize a variety of materials. In particular, the layer-by-layer (LbL) technique allows the coating of solid surfaces to give them several functionalities, including controlled release of bioactive agents. At present there are a large number of applications of the LbL technique; however, it is still little explored in the area of textiles. In this review we present an overview of LbL for textile materials made from synthetic or natural fibers. More specifically, LbL is presented as a method for obtaining new bioactive cotton (as in cellulosic fibers) for potential application in the medical field. We also review recent progress in the embedding of active agents in adsorbed multilayers as a novel way to provide the system with a “reservoir” where bioactive agents can be loaded for subsequent release.The authors would like to thank Fundação para a Ciência e Tecnologia (FCT) for the funding granted for the project PTDC/EBB-BIO/113671/2009 (FCOMP-01-0124-FEDER- 014752) Skin2Tex. Also, we would like to thank Fundo Europeu de Desenvolvimento Regional (FEDER) through COMPETE – Programa Operacional Factores de Competitividade (POFC) for co-funding

Applications of the Density Matrix Renormalization Group to Exchange-Coupled Transition Metal Systems

Transition metal complexes containing magnetically interacting open-shell ions are important for diverse areas of molecular science. The reliable prediction and computational analysis of their electronic structure and magnetic properties, either in qualitative or quantitative terms, remain a central challenge for theoretical chemistry. The use of multireference methods is in principle the ideal approach to the inherently multireference problem of exchange coupling in oligonuclear transition metal complexes; however, the applicability of such methods has been severely restricted due to their computational cost. In recent years, the introduction of the density matrix renormalization group (DMRG) to quantum chemistry has enabled the multireference treatment of chemical problems with previously unattainable numbers of active electrons and orbitals. This development also paved the way for the first-principles multireference treatment of magnetic properties in the case of exchange-coupled transition metal systems. Here, the first detailed applications of DMRG-based methods to exchange-coupled systems are reviewed and the lessons learned so far regarding the applicability, apparent limitations, and future promise of this approach are discussed