Evaluation of microvascular endothelial function is essential for investigating the pathophysiology and treatment of cardiovascular and metabolic diseases. Although laser speckle contrast imaging technology is well accepted as a noninvasive methodology for assessing microvascular endothelial function, it has never been used to compare male patients with coronary artery disease with male age-matched healthy controls. Thus, the aim of this study was to determine whether laser speckle contrast imaging could be used to detect differences in the systemic microvascular functions of patients with established cardiovascular disease (n=61) and healthy age-matched subjects (n=24). Cutaneous blood flow was assessed in the skin of the forearm using laser speckle contrast imaging coupled with the transdermal iontophoretic delivery of acetylcholine and post-occlusive reactive hyperemia. The maximum increase in skin blood flow induced by acetylcholine was significantly reduced in the cardiovascular disease patients compared with the control subjects (74 vs 116%; P<0.01). With regard to post-occlusive reactive hyperemia-induced vasodilation, the patients also presented reduced responses compared to the controls (0.42±0.15 vs 0.50±0.13 APU/mmHg; P=0.04). In conclusion, laser speckle contrast imaging can identify endothelial and microvascular dysfunctions in male individuals with cardiovascular disease. Thus, this technology appears to be an efficient non-invasive technique for evaluating systemic microvascular and endothelial functions, which could be valuable as a peripheral marker of atherothrombotic diseases in men.

This study compared strategies to equalize the volume of aerobic exercise performed with different intensities by Wistar rats, based on the distance covered during exercise bouts and energy expenditure (EE, isocaloric sessions) obtained from oxygen uptake (V̇O2) or respiratory exchange ratio (RER). Thirty-three male rats (270.5±12.8 g) underwent maximal exercise tests to determine V̇O2 reserve (V̇O2R), being randomly assigned to three groups: moderate-intensity continuous exercise at speed corresponding to 50% V̇O2R (MIC; n=11); high-intensity continuous exercise at 80% V̇O2R (HIC; n=11); and high-intensity intermittent exercise (HII; n=11) at 60% V̇O2R (3 min) and 80% V̇O2R (4 min). Exercise duration was calculated individually to elicit EE of 5 kcal in each session. No difference between groups was found for total running distance (MIC: 801±46, HIC: 734±42, HII: 885±64 m; P=0.13). Total EE measured by RER was systematically underestimated compared to values obtained from V̇O2 (HII: 4.5% and MIC: 6.2%, P<0.05). Total EE (calculated from V̇O2), and duration of HIC bouts (2.8 kcal and 30.8±2.2 min) were lower (P<0.0001) than in MIC (4.9 kcal and 64.7±1.8 min) and HII (4.7 kcal and 46.9±2.2 min). Predicted and actual values of total V̇O2, total EE, and duration of isocaloric sessions were similar in MIC and HII (P>0.05), which were both higher than in HIC (P<0.0001). In conclusion, the time to achieve a given EE in exercise bouts with different intensities did not correspond to the total distance. Therefore, the volume of aerobic exercise in protocols involving Wistar rats should be equalized using EE rather than total covered distance.

Neste trabalho desenvolveu-se um novo método de produção fibras de hidroxiapatite (HA), combinando a técnica de electrofiação com um sistema sol-gel de base não-alcóxida, utilizando precursores baratos. Como precursores de fósforo e de cálcio, foram usados o pentóxido de fósforo (P2O5) e o nitrato de cálcio tetrahidratado (Ca(NO3)2.4H2O), respectivamente. As fibras obtidas resultam da electrofiação de uma mistura do gel formado a partir do sistema Ca(NO3)2.4H2O/P2O5 com soluções poliméricas de polivinilpirrolidona (PVP) em água e misturas etanol/água. As fibras obtidas foram analisadas quanto à sua morfologia (Microscopia Electrónica de Varrimento, MEV), composição química (Espectroscopia de Infravermelho de transformada de Fourier, FTIR) e estrutural (Difracção de raios-X, DRX). Obtiveram-se nano e microfibras, maioritariamente constituídas por HA carbonatada do tipo B e com vestígios de óxido de cálcio (CaO) e de β-fosfato tricálcico (β-TCP). Pela análise de MEV verificou-se que uma maior concentração de PVP nas soluções de electrofiação conduz à formação de fibras de forma cilíndrica e que uma maior quantidade de água permite obter fibras de menor diâmetro e com menor dispersão de diâmetros. As fibras de HA produzidas têm potencial para a utilização quer biotecnológica (por ex. membranas de permuta iónica), quer biomédica (por ex. matrizes para crescimento de células ósseas).

This paper reports a new method of producing hydroxyapatite (HA) fibres, combining electrospinning and a non-alcoxide sol-gel system, using cheap precursors. Phosphorus pentoxide (P2O5) and calcium nitrate tetrahydrate (Ca(NO3)2.4H2O) were used as precursors of phosphorus and calcium, respectively. The fibres were electrospun from a mixture of the gel formed from the system Ca(NO3)2.4H2O/P2O5 with polymeric solutions of polyvinylpyrrolidone (PVP) in water and ethanol/water mixtures. The fibres were analyzed for their morphology (Scanning Electron Microscopy, SEM), chemical composition (Fourier Transform Infrared Spectroscopy, FTIR) and structure (X-ray diffraction, XRD). Nano and microfibres were obtained, composed mainly of type B carbonated HA with traces of calcium oxide (CaO) and β-tricalcium phosphate (β-TCP). From SEM analysis it was found that higher concentration of PVP in the electrospinning solutions leads to the formation of cylindrical fibres and that a larger amount of water allows for smaller diameter fibres and narrow diameters distribution. HA fibres produced have potential use either in Biotechnology (eg. Ion-exchange membranes) and Biomedicine (eg. Scaffolds for Tissue Engineeering).

O presente trabalho visa a produção de biobaterias a partir de membranas obtidas pela técnica de electrofiação. Com este trabalho pretendeu-se desenvolver um dispositivo electroquímico (biobateria) capaz de gerar energia eléctrica a partir de biofluidos, como a transpiração e o sangue, e com capacidade de satisfazer as necessidades de dispositivos electrónicos de baixo consumo. Para o desenvolvimento das biobaterias, começou-se por produzir as membranas de acetato de celulose por electrofiação. Estas membranas são utilizadas como suporte físico (substrato) e separador, sendo os eléctrodos depositados sob a forma de filme fino, em ambas as faces da membrana, formando o dispositivo electroquímico. O comportamento electroquímico da membrana foi analisado por voltametria cíclica, pretendendo-se averiguar a existência de possíveis reacções electroquímicas. De um modo geral, verificou-se que a produção de energia depende não só dos materiais que formam o ânodo e o cátodo, como também da espessura da membrana. Com o intuito de demonstrar as potencialidades, para a aplicação em causa, estes dispositivos foram testados sobre a pele suada, apresentado valores de tensão e corrente bastante promissores.

This research work envisages the production of bio-batteries based on electrospun membranes.The present work aims at the development of an electrochemical device (bio-battery) able to generate electrical power from body fluids, like sweat or blood, to supply small power consumption electronic devices.To the development of these bio-batteries, cellulose acetate membranes were made with a matrix of nanofibers produced by electrospinning. The cellulose acetate membrane works both as support and as a separator. Thin films were deposited on both surfaces of the membrane to form the electrodes of the electrochemical device.The electrochemical behavior of membranes was analysed by cyclic voltammetry in order to evaluate the electrochemical reactions. The power generated by these devices depends not only on the materials used as electrodes, but also on the membrane thickness. In order to demonstrate the great potential of these electrochemical devices, bio-batteries prototypes were tested in sweated skin, demonstrating promising voltage and current values.