In vitro and in vivo antithrombotic and antioxidant properties of microencapsulated brewers’ spent grain peptides

Antioxidant and antithrombotic activities of microencapsulated brewers’ spent grain peptides (BSGH-C) after simulated gastrointestinal digestion (SGID) and the in vivo properties using a model of growing Wistar rats fed with sucrose-rich diet (SRD) were determined. Microencapsulation reduced the cleavage of peptides (66.5 vs. 39.2%), partially preserved the in vitro antioxidant activity (ABTS⁺ inhibition and FRAP) and reduced the in vitro antithrombotic activity. SRD diet produced a pro-oxidant and pro-thrombotic systemic environment in rats, which was reversed by the consumption of BSGH-C. A positive correlation between in vitro antioxidant and antithrombotic activity of BSGH-C after SGID with the respective in vivo effects observed in rats fed BSGH-C (r = 0.9997 and r = 0.9411, respectively) was established. The goodness of both, the in vitro models determining bioactive properties after SGID, and the microencapsulation protecting the peptides from gastrointestinal environment were demonstrated. Thus, it was possible to produce microcapsules with bioavailable bioactive BSG peptides.     

Bioactive Phaseolus lunatus peptides release from maltodextrin/gum arabic microcapsules obtained by spray drying after simulated gastrointestinal digestion

Bioactive peptides can be protected from the gastrointestinal environment by microencapsulation. The aim was to assess the effect of simulated gastrointestinal digestion on bioactive properties of P. lunatus peptides (ACE-I, α-glucosidase, α-amylase, and dipeptidyl peptidase-IV inhibition) microencapsulated by spray drying using maltodextrin/gun arabic in optimal formula. Microcapsules were formulated using a 2² factorial design. The simultaneous effect of P. lunatus hydrolysate (4 and 10 g 100 g⁻¹) and proportion of maltodextrin/gum arabic (25:75 and 75:25 g 100 g⁻¹) on yield, protein efficiency, size, protein release at pH 2.0 and pH 7.0 of the different microcapsules was studied. Microcapsules with maximum yield, protein efficiency, and protein release at pH 7.0, and minimum protein release at pH 2.0 were subjected to simulated gastrointestinal digestion. Microcapsules obtained in optimal formula preserved the α-glucosidase, α-amylase, and dipeptidyl peptidase-IV inhibitory activity of P. lunatus peptides after in vitro gastrointestinal digestion.     

Effect of heat-treated wheat germ on dough properties and crackers quality

This study aims to analyse the influence of heat-treated wheat germ on dough properties and cracker quality. Different substitution levels of wheat flour were evaluated (0%, 10%, 20% and 30%). Dough rheological properties and stress relaxation behaviour were determined. Chemical characteristics, baking performance, texture, water activity and sensory analyses were performed on crackers. Wheat germ weakened the dough structure. The following mechanisms were suggested to explain this weakening effect: the addition of wheat germ diluted gluten; flour components and germ competed for water and decreased the water availability for gluten formation; and germ particles physically disrupted the continuity of the gluten network. Nevertheless, good quality crackers were obtained and their nutritional value was improved, with remarkable increments in protein, fibre and mineral contents. Also, high acceptance in sensory evaluation was recorded at substitution levels of 20% and 30% of germ, compared to control sample (0%).     

Nitric oxide metabolism in heart mitochondria

Normal cardiac function is accomplished through a continuous energy supply provided by mitochondria. Heart mitochondria are the major source of reactive oxygen and nitrogen species: superoxide anion (O₂-) and nitric oxide (NO). NO production by mitochondrial NOS (mtNOS) is modified by metabolic state and shows an exponential dependence on Δψ. The interaction between mtNOS and complexes I and IV might be a mechanism involved in the regulation of mitochondrial NO production. NO exerts a high affinity, reversible and physiological inhibition of cytochrome c oxidase activity. A second effect of NO on the respiratory chain is accomplished through its interaction with ubiquinol-cytochrome c oxidoreductase. The ability of mtNOS to regulate mitochondrial O₂ uptake and O₂- and H₂O₂ productions through the interaction of NO with the respiratory chain is named mtNOS functional activity. Together, heart mtNOS allows NO to optimize the balance between cardiac energy production and utilization, and to regulate the steady-state concentrations of other oxygen and nitrogen species.     

Condensation of Fluids Confined in Non-rigid Nanopores: With a Little Help from the Substrate

Fluids adsorbed in nanopores exert a force on the substrate that produces a compression or expansion of the host. Although this effect has been observed experimentally and computationally, an overwhelming majority of the theoretical studies have assumed that the environment provides a fixed, static potential in which the adsorbate moves. In a recent paper (H.-Y. Kim, S.M. Gatica, G. Stan and M.W. Cole, J. Low Temp. Phys. (this issue) 2009) we showed that the relaxation of the substrate is not limited to affecting the capacity of uptake, but has dramatic consequences on the physical properties of the adsorbates, like phase transitions and the energetics in low dimensions. For example, ³He in a rigid 1D pore is a gas, and in a non-rigid carbon nanotube is a liquid. In this paper we explore more situations involving classical and quantum fluids in slit pores and in bundles of carbon nanotubes. We find that, due to the cooperation of the relaxing substrate, confined classical gases condense at higher temperatures compared to extremely rigid substrates and ³He has a cohesive energy of up to 9.5 K when confined within a narrow non-rigid slit pore. We observe that a compression of a bundle of nanotubes of less than 0.02% gives rise to changes of up to 9% in the critical temperature.     

Constitutive model to predict flow of cohesive powders in bench scale hoppers

This communication empirically correlates flow in two systems; an instrumented rotating drum (GDR) and a set of bench scale hoppers. A flow index obtained from measurements in the GDR is directly correlated to the flow through hoppers, providing a predictive method for hopper design and a convenient experimental test for screening materials and determining their suitability for specific hopper systems. Simulations were performed to understand the dynamics of flow in hoppers by using the same flow parameters in hoppers and rotating cylinders. Simulations showed that as cohesion increased it becomes harder for the particles to flow through the hoppers, in good agreement with the experiments. The effect of hopper angle also yields similar findings to experiments for Avicel, K=60, where the powder does not flow through the 45° hopper but flows well in a 75° hopper. Simulations were also used to calculate the normal forces on the walls of the hopper and the wall pressure distributions in both hoppers. As depth increases, the wall pressure increases for all cases. Finally, the simulations also helped understand the different flow behaviors (funnel and mass flow) that take place in a hopper. The simulated dynamics of flow in the rotating drum and in the hopper correlate very closely to experiments, indicating that the model cohesion parameters are, as desirable, material-specific but independent of geometry.     

Radiolysis Studies of Oxidation and Nitration of Tyrosine and Some Other Biological Targets by Peroxynitrite-Derived Radicals

The widespread interest in free radicals in biology extends far beyond the effects of ionizing radiation, with recent attention largely focusing on reactions of free radicals derived from peroxynitrite (i.e., hydroxyl, nitrogen dioxide, and carbonate radicals). These radicals can easily be generated individually by reactions of radiolytically-produced radicals in aqueous solutions and their reactions can be monitored either in real time or by analysis of products. This review first describes the general principles of selective radical generation by radiolysis, the yields of individual species, the advantages and limitations of either pulsed or continuous radiolysis, and the quantitation of oxidizing power of radicals by electrode potentials. Some key reactions of peroxynitrite-derived radicals with potential biological targets are then discussed, including the characterization of reactions of tyrosine with a model alkoxyl radical, reactions of tyrosyl radicals with nitric oxide, and routes to nitrotyrosine formation. This is followed by a brief outline of studies involving the reactions of peroxynitrite-derived radicals with lipoic acid/dihydrolipoic acid, hydrogen sulphide, and the metal chelator desferrioxamine. For biological diagnostic probes such as ‘spin traps’ to be used with confidence, their reactivities with radical species have to be characterized, and the application of radiolysis methods in this context is also illustrated.     

MG-Pe: A Novel Galectin-3 Ligand with Antimelanoma Properties and Adjuvant Effects to Dacarbazine

Melanoma is a highly metastatic and rapidly progressing cancer, a leading cause of mortality among skin cancers. The melanoma microenvironment, formed from the activity of malignant cells on the extracellular matrix and the recruitment of immune cells, plays an active role in the development of drug resistance and tumor recurrence, which are clinical challenges in cancer treatment. These tumoral metabolic processes are affected by proteins, including Galectin-3 (Gal-3), which is extensively involved in cancer development. Previously, we characterized a partially methylated mannogalactan (MG-Pe) with antimelanoma activities. In vivo models of melanoma were used to observe MG-Pe effects in survival, spontaneous, and experimental metastases and in tissue oxidative stress. Analytical assays for the molecular interaction of MG-Pe and Gal-3 were performed using a quartz crystal microbalance, atomic force microscopy, and contact angle tensiometer. MG-Pe exhibits an additive effect when administered together with the chemotherapeutic agent dacarbazine, leading to increased survival of treated mice, metastases reduction, and the modulation of oxidative stress. MG-Pe binds to galectin-3. Furthermore, MG-Pe antitumor effects were substantially reduced in Gal-3/KO mice. Our results showed that the novel Gal-3 ligand, MG-Pe, has both antitumor and antimetastatic effects, alone or in combination with chemotherapy.     

Everyday use of computer-mediated communication tools and its evolution over time: An ethnographical study with older people

Based on a 3-year ethnographical study, this paper discusses the prolonged use of computer-mediated communication (CMC) tools by approximately 400 older people in an adult education centre in Barcelona (Spain). Contrary to oversimplified views of older people as ICT users, this paper shows that they make a very rich use of CMC tools. Relevant elements of this use are their permanent desire to feel and be included, social, independent and competent ICT users. Despite the numerous interaction issues they face when using ICT, some are constant across different tools. Difficulties due to cognition limit their interactions more severely than those problems due to perceiving visual information or using the mouse. By examining the longitudinal aspect of the study, this paper addresses the evolution of technology use and whether the interaction issues that most of the current older people exhibit will be relevant when today’s more ICT literate young adults grow older. Interaction issues due to cognition are time-persistent, and independent of both experience and practice with ICT. Difficulties reading from the screen or using input devices are overcome with ICT experience. The strategies adopted by older people for coping with all these interaction issues are always targeted at feeling and being included, social, independent and competent ICT users. The results deepen current understanding of tools use in connecting older people with their social circles and the interaction issues most of them encounter when using ICT. The results also suggest that cognitive-related problems will be the most important ones in our work with the next generation of older people.