Wear resistance of experimental titanium alloys for dental applications

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Preparation, characterization and application of a nanostructured composite: Octakis(cyanopropyldimethylsiloxy)octasilsesquioxane

Octakis(cyanopropyldimethylsiloxy)octasilsesquioxane was prepared and characterized by C-13, Si-29 NMR (MAS), SEM, FF-IR, XRD and thermogravimetric techniques. The four groups alpha, beta, gamma, kappa (to the terminal silicon atom), associated with an acrylonitrile, were clearly seen in the C-13 NMR (alpha-CH2 at 17.9; P-CH2 at 31.3; gamma-CH, at 50.4; K-C N at 59.0 ppm). The Si-29 NMR spectrum of the final product, exhibits only Q type silicon signal, ascribed to Q(4) (-118.0 ppm). The presence of acrylonittile substituted for octameric cube confers a relative change phase and thermal stability to the material. With regard to the applications for this new material, it was intended, in this case, to react with Na-2[Fe(CN)(5)NH3] by chemical substitution. This composite was incorporated into a carbon paste electrode and the electrochemical studies were performed by cyclic voltammetry. The cyclic voltammogram of the modified graphite paste electrode, showed one redox couples with formal potential (E-1/2(ox)) = 0.24 V versus SCE. (c) 2006 Elsevier B.V. All rights reserved.

Perfil eletroforético das proteínas séricas de serpentes Crotalus durissus terrificus (cascavel) criadas em cativeiro

As serpentes peçonhentas dos gêneros Bothrops e Crotalus têm sido mantidas em cativeiro visando à extração de venenos para a produção de imunobiológicos. O conhecimento da fisiologia desses animais e as alterações na concentração de proteínas e suas frações séricas são importantes para a identificação precoce de importantes enfermidades que cursam com estados de hipoproteinemia e hiperproteinemia. O objetivo do trabalho foi determinar a concentração de proteína total e o perfil eletroforético das proteínas séricas de serpentes Crotalus durissus terrificus (cascavel) criadas em cativeiro. Foram colhidas amostras de sangue da veia coccígea ventral de 21 serpentes adultas e sadias, divididas em dois grupos: Grupo 1 de 12 machos com peso médio de 588,89±193,55g, e Grupo 2 de nove fêmeas com peso médio de 708,33±194,04g. A proteína total sérica foi determinada pelo método de refratometria e a eletroforese em gel de agarose. Obtiveram-se valores da proteína total sérica (g/dL) de 4,51±0,50 para machos e de 4,82±0,72 para fêmeas, e para machos e fêmeas de 4,64±0,61. Foram identificadas pela eletroforese quatro frações protéicas (g/dL): albumina, a, b, g-globulinas e calculada a relação albumina:globulina. As serpentes fêmeas apresentaram maiores valores para as variáveis, albumina e para a relação albumina/globulina (AG) diferindo significativamente (P<0,05) do grupo de machos, porém sem significado clínico.

Transferência de imunidade passiva em bezerros das raças Nelore e Limousin e proteinograma sérico nos primeiros quatro meses de vida

Com o objetivo de investigar alguns aspectos relacionados à transferência de imunidade passiva em bovinos de corte, foram selecionados 90 bezerros aparentemente sadios, 45 da raça Nelore e 45 da raça Limousin, distribuídos em 3 grupos (com 15 bezerros cada) de acordo com o número de parições de suas mães: primeira cria; segunda cria; e terceira ou mais crias. Amostras de sangue foram colhidas de cada bezerro entre 24 e 36 horas de vida e com 15, 30, 60, 90 e 120 dias. Determinaram-se as concentrações de proteína total no soro (PT) e no plasma (PPT), a atividade sérica da gamaglutamiltransferase (GGT), e as concentrações séricas de albumina, alfa, beta e gamaglobulinas por eletroforese em gel de agarose e de IgG estimada por meio do método de turvação pelo sulfato de zinco. Empregou-se a análise de variância bifatorial para as variáveis mensuradas na primeira colheita. O comportamento das variáveis em função da idade foi estudado por meio da análise de variância de medidas repetidas. Correlações foram estabelecidas entre as variáveis. A transferência de imunidade passiva foi bem sucedida nos bezerros de ambas as raças e o número de parições das mães não interferiu no processo. As concentrações mais elevadas de gamaglobulinas ao término do primeiro dia de vida declinaram até valores mínimos aos 60 dias. A partir dessa idade, a elevação conseqüente à produção ativa de anticorpos foi mais precoce nos bezerros taurinos e mais lenta nos zebuínos. A gamaglobulina, ao término do primeiro dia de vida, correlacionou-se com as seguintes variáveis: IgG (r=0,859), PPT (r=0,807), PT (r=0,811) e GGT (r=0,399). O fator etário exerceu efeito sobre todas as variáveis mensuradas. As variações das proteínas séricas obedeceram a um padrão de comportamento fisiológico ao longo dos quatro primeiros meses de vida, de forma geral, não distinto em taurinos e zebuínos.

Mechanical, physical, and chemical characterization of Ti-35Nb-5Zr and Ti-35Nb-10Zr casting alloys

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Purinergic mechanisms of lateral parabrachial nucleus facilitate sodium depletion-induced NaCl intake

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Phosphorus magnetic resonance spectroscopy in malformations of cortical development

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

ROLE of TLR2 and TLR4 on human neutrophil functions against Paracoccidioides brasiliensis

In paracoccidioidomycosis, a systemic mycosis caused by the fungus Paracoccidioides brasiliensis (Pb), studies have focused on the role of neutrophils that are involved in the primary response to the fungus. Neutrophil functions are regulated by pro- and anti-inflammatory cytokines. Molecular mechanisms involved in this process are not fully understood, but there are strong evidences about the involvement of toll-like receptors (TLRs). We aimed at evaluating TLR2 and TLR4 expression on human neutrophils activated by GM-CSF, IL-15, TNF-alpha or IFNgamma and challenged with a virulent strain of P. brasiliensis (Pb18). Moreover, we asked if these receptors have a role on fungicidal activity, H(2)O(2) and IL-6, IL-8, TNFalpha and IL-10 production, by activating and challenging cells. All cytokines increased TLR2 and TLR4 expression. Pb18 also increased TLR2 expression, inducing an additional cytokine effect. on the contrary, it inhibited TLR4 expression. All cytokines increased neutrophil fungicidal activity and H(2)O(2) production; however, this process was not associated with TLR2 or TLR4. Neutrophil activation by GMCSF and TNF-alpha resulted in a significant increase of IL-8 production, while IL-15 and IFN-alpha have no effect. Pb18 also augmented IL-8 expression, inducing an additional effect to that of cytokines. None of the cytokines activated neutrophils by releasing IL-10. This cytokine was only detected after Pb18 challenge. Interestingly, IL-8 and IL-10 production involved TLR2 and mainly TLR4 modulation. The present results suggest that Pb18 interaction with neutrophils through TLR2 and TLR4 with consequent IL-8 and IL-10 production may be considered a pathogenic mechanism in paracoccidioidomycosis.

Structure of chorismate synthase from Mycobacterium tuberculosis

In bacteria, fungi, plants, and apicomplexan parasites, the aromatics compounds, such as aromatics amino acids, are synthesized through seven enzymes from the shikimate pathway, which are absent in mammals. The absence of this pathway in mammals make them potential targets for development of new therapy against infectious diseases, such as tuberculosis, which is the world's second commonest cause of death from infectious disease. The last enzyme of shikimate pathway is the chorismate synthase (CS), which is responsible for conversion of the 5-enolpyruvylshikimate-3-phosphate to chorismate. Here, we report the crystallographic structure of CS from Mycobacterium tuberculosis (MtCS) at 2.65 angstrom resolution. The MtCS structure is similar to other CS structures, presenting beta-alpha-beta sandwich structural topology, in which each monomer of MtCS consists of a central helical core. The MtCS can be described as a tetramer formed by a dimer of dimers. However, analytical ultracentrifugation studies suggest the MtCS is a dimer with a more asymmetric shape than observed on the crystallographic dimer and the existence of a low equilibrium between dimer and tetramer. Our results suggest that the MtCS oligomerization is concentration dependent and some conformational changes must be involved on that event. (c) 2005 Elsevier B.V. All rights reserved.

Role of PKC and CaV1.2 in Detrusor Overactivity in a Model of Obesity Associated with Insulin Resistance in Mice

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Molecular models of NS3 protease variants of the Hepatitis C virus

Background: Hepatitis C virus (HCV) currently infects approximately three percent of the world population. In view of the lack of vaccines against HCV, there is an urgent need for an efficient treatment of the disease by an effective antiviral drug. Rational drug design has not been the primary way for discovering major therapeutics. Nevertheless, there are reports of success in the development of inhibitor using a structure-based approach. One of the possible targets for drug development against HCV is the NS3 protease variants. Based on the three-dimensional structure of these variants we expect to identify new NS3 protease inhibitors. In order to speed up the modeling process all NS3 protease variant models were generated in a Beowulf cluster. The potential of the structural bioinformatics for development of new antiviral drugs is discussed.Results: the atomic coordinates of crystallographic structure 1CU1 and 1DY9 were used as starting model for modeling of the NS3 protease variant structures. The NS3 protease variant structures are composed of six subdomains, which occur in sequence along the polypeptide chain. The protease domain exhibits the dual beta-barrel fold that is common among members of the chymotrypsin serine protease family. The helicase domain contains two structurally related beta-alpha-beta subdomains and a third subdomain of seven helices and three short beta strands. The latter domain is usually referred to as the helicase alpha-helical subdomain. The rmsd value of bond lengths and bond angles, the average G-factor and Verify 3D values are presented for NS3 protease variant structures.Conclusions: This project increases the certainty that homology modeling is an useful tool in structural biology and that it can be very valuable in annotating genome sequence information and contributing to structural and functional genomics from virus. The structural models will be used to guide future efforts in the structure-based drug design of a new generation of NS3 protease variants inhibitors. All models in the database are publicly accessible via our interactive website, providing us with large amount of structural models for use in protein-ligand docking analysis.

Dificuldades no diagnóstico laboratorial das hemoglobinopatias

Há vários tipos de hemoglobinopatias que são caracterizados por variantes das hemoglobinas anormais (ex: Hb S, Hb C, Hb Instáveis,etc) e por talassemias (ex: tal. alfa, tal. beta, tal.beta/delta,etc) As hemoglobinopatias são consideradas como uma das doenças genéticas mais comuns em todo o mundo, com prevalência de portadores heterozigotos de seus principais tipos em aproximadamente 5% da população mundial. Devido à heterogenidade clínica e genética dessas alterações genéticas é fundamental estabelecer a investigação laboratorial das diferentes formas de hemoglobinas variantes e de talassemias. Este artigo apresenta as principais dificuldades laboratoriais que envolvem a complexidade molecular das hemoglobinopatias.

Diagnóstico de hemoglobinopatias em recém-nascidos do Hospital de Base de São José do Rio Preto-SP

The neonatal period is considered the most effective for the screening of hemoglobinopathies. This allows prophylaxis and prevention, improving the patient's survival and guidance of parents and heterozygote carriers. The present work aims at the early detection of abnormal hemoglobins, the establishment of standard analysis and to examine the viability of the prevention program. Blood samples were collected by heel stick and from blood cord of children born in the Hospital de Base São José do Rio Preto, from April 1998 to November 1999. Electrophoresis and cytological, biochemical, cromatographic analyses were made for abnormal hemoglobin characterization. A total of 1,478 neonatal blood samples were analyzed in which 14.62% presented with hemoglobins alterations: 3.32% had Hb S; 0.61% had Hb C; 7.44% were suggestive of alpha thalassemia; 1.55% were suggestive of beta thalassemia, and 1.70% had alpha/beta thalassemia interactions. The samples collected from the blood cord showed better results in all analyses while the blood samples collected by heel stick on filter paper, were applicable to only specific methodologies. The routine laboratory methods allowed identification of the thalassemic and variant forms, and isoelectric focusing presented sensitivity only for variant identification in this age range. The suspected cases were reassessed after six months, which permitted genetic counseling of their family members and clinic attendance. A multidisciplinary approach in programs of this kind is fundamental for its success.

Caracterização de hemoglobina N-Baltimore em doador de sangue de São José do Rio Preto, SP

As alterações que envolvem as globinas devem-se a modificações em genes responsáveis pela seqüência e estrutura das cadeias polipeptídicas, bem como aos genes reguladores da síntese destas cadeias. Hemoglobinas variantes apresentam estrutura química diferente da hemoglobina normal correspondente, resultante de mutações em uma ou mais bases nitrogenadas, ocasionando a troca de aminoácidos nas globinas alfa, beta, delta ou gama. A hemoglobina N-Baltimore é uma variante de globina beta, com substituição da lisina, na posição 95, por ácido glutâmico, apresentando mobilidade eletroforética mais rápida que a hemoglobina A em pH alcalino. Nas análises eletroforéticas em pH alcalino realizadas em doadores de sangue do Hemocentro de São José do Rio Preto (SP) identificamos a presença de portador de hemoglobina rápida em heterozigose, posteriormente confirmada por focalização isoelétrica e cromatografia líquida de alta pressão (HPLC). Os estudos de hemoglobinas anormais em doadores de sangue permitem a identificação de variantes raras e possibilitam o aconselhamento genético adequado a cada caso com estudo familial.

Connection coefficients and zeros of orthogonal polynomials

We discuss an old theorem of Obrechkoff and some of its applications. Some curious historical facts around this theorem are presented. We make an attempt to look at some known results on connection coefficients, zeros and Wronskians of orthogonal polynomials from the perspective of Obrechkoff's theorem. Necessary conditions for the positivity of the connection coefficients of two families of orthogonal polynomials are provided. Inequalities between the kth zero of an orthogonal polynomial p(n)(x) and the largest (smallest) zero of another orthogonal polynomial q(n)(x) are given in terms of the signs of the connection coefficients of the families {p(n)(x)} and {q(n)(x)}, An inequality between the largest zeros of the Jacobi polynomials P-n((a,b)) (x) and P-n((alpha,beta)) (x) is also established. (C) 2001 Elsevier B.V. B.V. All rights reserved.