Resumo O fosfato tricálcico (TCP) é um biomaterial que está sendo produzido em diversas aplicações biomédicas, além de sua biocompatibilidade e capacidade osteocondutora. Polímeros biodegradáveis de origem natural ou sintética, como quitosana e poli(álcool vinílico) (PVA), vêm sendo utilizados para aplicações de engenharia de tecidos por apresentarem as propriedades da fase orgânica nativa do tecido ósseo. Desse modo, o objetivo deste trabalho foi a obtenção de filmes finos cerâmicos baseados em TCP, quitosana e PVA através do método de tape casting. Dados de viscosidade para todas as suspensões mostraram-se ideais para o processamento escolhido. As curvas termogravimétricas demonstraram perfis semelhantes e foi possível observar que com o aumento do teor de quitosana ocorreu maior perda de massa total. Reflexões de DRX relacionadas à fase β-TCP de estrutura ortorrômbica foram encontradas, evidenciando que não houve transformação de fases. A análise de MEV revelou graus de rugosidade nas superfícies dos filmes com pouca influência do aumento do conteúdo de quitosana.

Abstract Tricalcium phosphate (TCP) is a biomaterial produced in several biomedical applications, in addition to having biocompatibility and osteoconductive capacity. Biodegradable polymers of natural or synthetic origin such as chitosan and polyvinyl alcohol (PVA) have been used for tissue engineering applications because they have the properties of the native organic phase of bone tissue. Thus, the objective of this study was to obtain ceramic tapes based on TCP, chitosan, and PVA through the tape casting method. The viscosity data for all suspensions were ideal for the chosen processing. The thermogravimetric curves showed similar profiles, and it was possible to observe that a greater total mass loss occurred with the increase in the chitosan content. XRD reflections related to the β-TCP phase of the orthorhombic structure were found, showing no phase transformation. SEM analysis showed degrees of roughness on the film surfaces with little influence from the increase in chitosan content.

Cryopreservation of sperm is important to preserve the germplasm from animals of genetic value, which can die unexpectedly. This study compares conventional and automated methods of cryopreservation of spermatozoa obtained from the epididymis of bulls post-mortem. Twenty-two epididymides were obtained from a commercial slaughterhouse. Spermatozoa were collected from the tail of the epididymis using the retrograde flow technique. Thus, the samples, which were diluted in 10 ml of extender without glycerol (Botubov® I, Botupharma, Botucatu, SP, Brazil), were evaluated on motility, sperm vigor, structural and functional (swelling hypoosmotic test) membrane integrity, mitochondrial activity, sperm viability and ADN fragmentation. The samples were divided into two aliquots and diluted in extender with glycerol (Botubov® II, Botupharma, Botucatu, SP, Brazil) at a concentration of 50x10(6) motile sperm/0.5 French straws. One sample was frozen by the conventional method (4 hours at 5°C, in a refrigerator and 20 min in nitrogen vapor) and the other by the automated method (Cryogen® Dualflex, Neovet, Uberaba, MG, Brazil). The parameters were higher in all the tests of fresh sperm samples, with the exception of the swelling hypoosmotic test, which showed no significant difference when the results were compared with sperm frozen by the conventional method. The average motility of fresh spermatozoa was 74%, and conventional and automated averages were 29 and 25%, respectively. Therefore, although cryopreservation techniques reduce sperm quality parameters, the viability of the sperm is maintained, and these methods can be used to preserve sperm.

La criopreservación de espermatozoides es importante para la preservación del germoplasma masculino de animales de valor zootécnico que pueden morir inesperadamente. Este estudio compara los métodos de criopreservación convencional y automatizado de espermatozoides colectados de la cola del epidídimo de toros post mortem. Fueron utilizados 22 epidídimos, colectados en una planta faenadora. Los espermatozoides fueron colectados con la técnica de flujo retrogrado utilizando medio diluyente sin crioprotector (Botubov®I, Botupharma. Botucatu, SP, Brasil), fueron analizados en cuanto a la motilidad, vigor, integridad estructural y funcional de la membrana plasmática, viabilidad, actividad mitocondrial e integridad del ADN. Los espermatozoides fueron separados en dos muestras y diluidos en medio con crioprotector (Botubov®II, Botupharma. Botucatu, SP, Brasil), fueron envasados en pajillas francesas, conteniendo 50x10(6) espermatozoides móviles por pajilla. Las pajillas fueron congeladas por los métodos convencional (4 °C, durante 4 horas, en nevera doméstica y 20 minutos por encima de la superficie liquida conteniendo nitrógeno líquido) y automatizado (Cryogen®,Neovet, Uberaba, MG, Brasil). Las muestras de espermatozoides frescos presentaron resultados superiores en todos los parámetros realizados comparados con los métodos de congelación convencional y automatizado, con excepción de los parámetros hipoosmóticos, donde las muestras de espermatozoides frescos no tuvieron alteraciones significativas comparadas con las muestras de espermatozoides criopreservados por el método convencional. La motilidad media de espermatozoides frescos fue de 74%, y de 29 y 25% con los métodos convencional y automatizado respectivamente. Así, aunque las técnicas de criopreservación reducen los parámetros de calidad espermática, se mantiene la viabilidad de los espermatozoides, pudiendo ser utilizada para la preservación espermática.

Heat transfer during the freezing of guava pulp conditioned in large containers such as in stacked boxes (34 L) and buckets (20 L) and unstacked drums (200 L) is discussed. The air velocities across the cross-section of the tunnel were measured, and the values in the outlet of the evaporator were used as the initial conditions in computational fluid dynamics (CFD) simulations. The model tested was turbulent standard k-ε. The CFD-generated convective heat transfer coefficients were mapped on the surfaces for each configuration and used in procedures for the calculation of freezing-time estimates. These estimates were compared with the experimental results for validation. The results showed that CFD determined representative coefficients and produced good correlations between the predicted and experimental values when applied to the freezing-time estimates for the box and drum configurations. The errors depended on the configuration and the adopted mesh (3-D grid) construction.

Os autores apresentam o relato de caso de um paciente com artropatia ocronótica. A ocronose é uma doença rara, de herança autossômica recessiva, manifestação clínica da alcaptonúria. O paciente apresenta clinicamente dor crônica lombar, fraqueza e limitação funcional dos ombros e joelhos, associada a urina de cor escura. O objetivo do tratamento ortopédico é o controle da dor e melhora das funções das articulações acometidas, realizando artroplastias quando necessário.

The authors report the case of a patient with ochronotic arthropathy. This rare, inherited disease of autossomal recessive trait is the clinical manifestation of alkaptonuria. The patient presented clinically with chronic low back pain, disability, pain and weakness / stiffness in his shoulders and knees associated with dark urine. The main purpose of the orthopaedic approach in this disease is to control the pain and improve the function of the affected joints by performing arthroplasties when necessary.

The mechanism whereby the immune system avoids self-aggression is one of the central issues of Immunology. The discovery of natural autoantibodies, mainly of IgM isotype, and of idiotypic interactions between antibodies indicates that elements of the immune system interact with self constituents and with themselves. Results of studies with soluble antibodies have indicated that the pool of circulating IgM represents the end result of a highly selective process of B cells activation and differentiation by self proteins resulting in the formation of a network. The objective of the present work was to determine the frequency of self-reacting B cells in normal mice. We were able to detect B cells that recognize self proteins present in extracts of different organs in normal adult, 2-3-month old, BALB/c and C57BL/6 mice with an ELISA spot assay. About 1% of total IgM-secreting cells among small, LPS-stimulated spleen cells reacted with organ extracts, whereas among large spleen cells the frequency was 5- to 10-fold lower. Immunization induced an increase in the frequency of IgM-secreting cells. The present results provide cellular evidence for the results of studies done at the serological level. The physiological role of these self-recognizing cells, as well as their participation in autoimmune processes, remain to be established