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Quitosana: derivados hidrossolúveis, aplicações farmacêuticas e avanços Translated title: Chitosan: hydrossoluble derivatives, pharmaceutical applications and recent advances

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      Translated abstract

      Chitin and chitosan are copolymers build from N-acetyl-D-glucosamine and D-glucosamine. The former is widely found in nature and yields the latter on deacetylation. The copolymers are being used for several purposes. Since 1977, when the First International Conference on Chitin and Chitosan was held in Boston, USA, the interest on chitin and chitosan has remarkably increased. This review emphasizes pharmaceutical applications of chitosan and its derivatives, and presents recent advances. Some therapeutical applications of these polymers are also discussed.

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      Bactericidal antibody against a representative epidemiological meningococcal serogroup B panel confirms that MATS underestimates 4CMenB vaccine strain coverage.

      4CMenB (Bexsero), a vaccine developed against invasive meningococcal disease caused by capsular group B strains (MenB), was recently licensed for use by the European Medicines Agency. Assessment of 4CMenB strain coverage in specific epidemiologic settings is of primary importance to predict vaccination impact on the burden of disease. The Meningococcal Antigen Typing System (MATS) was developed to predict 4CMenB strain coverage, using serum bactericidal antibody assay with human complement (hSBA) data from a diverse panel of strains not representative of any specific epidemiology. To experimentally validate the accuracy of MATS-based predictions against strains representative of a specific epidemiologic setting. We used a stratified sampling method to identify a representative sample from all MenB disease isolates collected from England and Wales in 2007-2008, tested the strains in the hSBA assay with pooled sera from infant and adolescent vaccinees, and compared these results with MATS. MATS predictions and hSBA results were significantly associated (P=0.022). MATS predicted coverage of 70% (95% CI, 55-85%) was largely confirmed by 88% killing in the hSBA (95% CI, 72-95%). MATS had 78% accuracy and 96% positive predictive value against hSBA. MATS is a conservative predictor of strain coverage by the 4CMenB vaccine in infants and adolescents. Crown Copyright © 2013. Published by Elsevier Ltd. All rights reserved.
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        Recent advances in QM/MM free energy calculations using reference potentials☆

        Background Recent years have seen enormous progress in the development of methods for modeling (bio)molecular systems. This has allowed for the simulation of ever larger and more complex systems. However, as such complexity increases, the requirements needed for these models to be accurate and physically meaningful become more and more difficult to fulfill. The use of simplified models to describe complex biological systems has long been shown to be an effective way to overcome some of the limitations associated with this computational cost in a rational way. Scope of review Hybrid QM/MM approaches have rapidly become one of the most popular computational tools for studying chemical reactivity in biomolecular systems. However, the high cost involved in performing high-level QM calculations has limited the applicability of these approaches when calculating free energies of chemical processes. In this review, we present some of the advances in using reference potentials and mean field approximations to accelerate high-level QM/MM calculations. We present illustrative applications of these approaches and discuss challenges and future perspectives for the field. Major conclusions The use of physically-based simplifications has shown to effectively reduce the cost of high-level QM/MM calculations. In particular, lower-level reference potentials enable one to reduce the cost of expensive free energy calculations, thus expanding the scope of problems that can be addressed. General significance As was already demonstrated 40 years ago, the usage of simplified models still allows one to obtain cutting edge results with substantially reduced computational cost. This article is part of a Special Issue entitled Recent developments of molecular dynamics.
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          Transmission dynamic modelling of the impact of human papillomavirus vaccination in the United Kingdom.

          Many countries are considering vaccination against human papillomavirus (HPV). However, the long-term impact of vaccination is difficult to predict due to uncertainty about the prevalence of HPV infection, pattern of sexual partnerships, progression of cervical neoplasias, accuracy of screening as well as the duration of infectiousness and immunity. Dynamic models of human papillomavirus (HPV) transmission were developed to describe the infection spread and development of cervical neoplasia, cervical cancer (squamous cell and adenocarcinoma) and anogenital warts. Using different combinations of assumptions, 9900 scenarios were created. Each scenario was then fitted to epidemiological data and the best-fitting scenarios used to predict the impact of vaccination. Results suggest that vaccinating 12-year-old girls at 80% coverage will result in a 38-82% reduction in cervical cancer incidence and 44-100% reduction in anogenital warts incidence after 60 years of an ongoing vaccination programme if vaccine protection lasts 20 years on average. The marginal benefit of vaccinating boys depends on the degree of protection achieved by vaccinating girls. (c) 2009 Elsevier Ltd. All rights reserved.
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            Author and article information

            Affiliations
            [1 ] Universidade de São Paulo Brazil
            Contributors
            Role: ND
            Role: ND
            Role: ND
            Journal
            qn
            Química Nova
            Quím. Nova
            Sociedade Brasileira de Química (São Paulo )
            1678-7064
            July 2006
            : 29
            : 4
            : 776-785
            S0100-40422006000400026 10.1590/S0100-40422006000400026

            http://creativecommons.org/licenses/by/4.0/

            Product
            Product Information: SciELO Brazil
            Categories
            CHEMISTRY, MULTIDISCIPLINARY

            General chemistry

            pharmaceutical applications, hydrossoluble derivatives, chitosan

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