Marine and freshwater algae and their products are in growing demand worldwide because of their nutritional and functional properties. Microalgae (unicellular algae) will constitute one of the major foods of the future for nutritional and environmental reasons. They are sources of high-quality protein and bioactive molecules with potential application in the modern epidemics of obesity and diabetes. They may also contribute decisively to sustainability through carbon dioxide fixation and minimization of agricultural land use. This paper reviews current knowledge of the effects of consuming edible microalgae on the metabolic alterations known as metabolic syndrome (MS). These microalgae include Chlorella, Spirulina (Arthrospira) and Tetraselmis as well as Isochrysis and Nannochloropsis as candidates for human consumption. Chlorella biomass has shown antioxidant, antidiabetic, immunomodulatory, antihypertensive, and antihyperlipidemic effects in humans and other mammals. The components of microalgae reviewed suggest that they may be effective against MS at two levels: in the early stages, to work against the development of insulin resistance (IR), and later, when pancreatic -cell function is already compromised. The active components at both stages are antioxidant scavengers and anti-inflammatory lipid mediators such as carotenoids and -3 PUFAs (eicosapentaenoic acid/docosahexaenoic acid; EPA/DHA), prebiotic polysaccharides, phenolics, antihypertensive peptides, several pigments such as phycobilins and phycocyanin, and some vitamins, such as folate. As a source of high-quality protein, including an array of bioactive molecules with potential activity against the modern epidemics of obesity and diabetes, microalgae are proposed as excellent foods for the future. Moreover, their incorporation into the human diet would decisively contribute to a more sustainable world because of their roles in carbon dioxide fixation and reducing the use of land for agricultural purposes.
13 June 2000 in European Journal of Applied Physiology
In recent years, the altitude acclimatization responses elicited by short-term intermittent exposure to hypoxia have been subject to renewed attention. The main goal of short-term intermittent hypobaric hypoxia exposure programs was originally to improve the aerobic capacity of athletes or to accelerate the altitude acclimatization response in alpinists, since such programs induce an increase in erythrocyte mass. Several model programs of intermittent exposure to hypoxia have presented efficiency with respect to this goal, without any of the inconveniences or negative consequences associated with permanent stays at moderate or high altitudes. Artificial intermittent exposure to normobaric hypoxia systems have seen a rapid rise in popularity among recreational and professional athletes, not only due to their unbeatable cost/efficiency ratio, but also because they help prevent common inconveniences associated with high-altitude stays such as social isolation, nutritional limitations, and other minor health and comfort-related annoyances. Today, intermittent exposure to hypobaric hypoxia is known to elicit other physiological response types in several organs and body systems. These responses range from alterations in the ventilatory pattern to modulation of the mitochondrial function. The central role played by hypoxia-inducible factor (HIF) in activating a signaling molecular cascade after hypoxia exposure is well known. Among these targets, several growth factors that upregulate the capillary bed by inducing angiogenesis and promoting oxidative metabolism merit special attention. Applying intermittent hypobaric hypoxia to promote the action of some molecules, such as angiogenic factors, could improve repair and recovery in many tissue types. This article uses a comprehensive approach to examine data obtained in recent years. We consider evidence collected from different tissues, including myocardial capillarization, skeletal muscle fiber types and fiber size changes induced by intermittent hypoxia exposure, and discuss the evidence that points to beneficial interventions in applied fields such as sport science. Short-term intermittent hypoxia may not only be useful for healthy people, but could also be considered a promising tool to be applied, with due caution, to some pathophysiological states.
Ricart, Antoni, Jaume Maristany, Núria Fort, Conxita Leal, Teresa Pagés, and Ginés Viscor. Effects of sildenafil on the human response to acute hypoxia and exercise. High Alt. Med. Biol. 6:43–49, 2005.–We examined the effects of the 5-phosphodiesterase (5-PDE) inhibitor sildenafil on pulmonary arterial pressure and some oxygen transport and cardiopulmonary parameters in humans during exposure to hypobaric hypoxia at rest and after exercise. In a double-blind study, 100 mg sildenafil or placebo was administered orally to 14 healthy volunteers 45 min before exposure to 5,000 m of simulated altitude. Arterial oxygen saturation (SaO2 ), heart rate (HR), tidal volume (VT), respiratory rate (RR), left ventricular ejection fraction (EF), and pulmonary arterial pressure (PAP) were measured first at rest in normoxia, at rest and immediately after exercise during hypoxia, and after exercise in normoxia. The increase in systolic PAP produced by hypoxia was significantly decreased by sildenafil at rest from 40.9 ± 2.6 to 34.9 ± 3.0 mmHg (–14.8%; p = 0.0046); after exercise, from 49.0 ± 3.9 to 42.9 ± 2.6 mmHg (–12.6%; p = 0.003). No significant changes were found in normoxia either at rest or after exercise. Measurements of the effect of sildenafil on exercise capacity during hypoxia did not provide conclusive data: a slight increase in SaO2 was observed with exercise during hypoxia, and sildenafil did not cause significant changes in ventilatory parameters under any condition. Sildenafil diminishes the pulmonary hypertension induced by acute exposure to hypobaric hypoxia at rest and after exercise. Further studies are needed to determine the benefit from this treatment and to further understand the effects of sildenafil on exercise capacity at altitude.
1 June 2000 in Wilderness & Environmental Medicine
With the ultimate goal of finding a straightforward protocol for acclimatization at simulated altitude, we evaluated the early effects of repeated short-term exposure to hypobaric hypoxia on the respiratory response to exercise in hypoxia. Nine subjects were exposed to a simulated altitude of 5000 m for 2 hours a day for 14 days. Arterial oxygen saturation (SaO2), expired volume per minute (VE), respiratory rate, tidal volume (VT), and heart rate were measured during rest and during exercise (cycloergometer, at 30% of maximum oxygen consumption at sea level), both in normoxia and at 5000 m of simulated altitude on the first and 15th days. On the same days, blood samples were obtained for hematological tests. During exercise in hypoxia, SaO2 rose from 65 to 71% (P = .02), and VE rose from 55.5 to 67.6 L.min-1 (P = .02) due to an increase in VT from 2 to 2.6 L (P = .003). No significant differences were found in any of the variables studied at rest either in normoxia or in hypoxia or in exercise in normoxia after the exposure program. In the second week, changes in packed cell volume and blood hemoglobin concentration were nonsignificant. After short-term intermittent exposure to hypobaric hypoxia, subjects increased their ventilatory response and SaO2 during exercise at simulated altitude. These changes may be interpreted as acclimatization to altitude. The monitoring of ventilatory response and SaO2 during moderate exercise in hypobaric hypoxia may be used to detect the first stages of acclimatization to altitude.
2 August 2012 in REDU. Revista de Docencia Universitaria
Este artículo presenta el proyecto desarrollado durante el año 2011 por las unidades y centros de formación de las universidades públicas catalanas. El proyecto se orienta a la mejora de la calidad del sistema de educación superior y de la actividad del profesorado universitario mediante planes de formación específicamente diseñados con esta finalidad, centrándose primeramente en la identificación de competencias docentes definidas por la comunidad académica. Partiendo del contexto de implementación del Espacio Europeo de Educación Superior se identifican aquellas competencias propias de la función docente, para que posteriormente puedan ser adquiridas, desarrolladas y evaluadas mediante la formación, identificando modelos, estrategias, instrumentos y recursos que lo permitan. El proceso de identificación de las competencias docentes del profesorado universitario se ha desarrollado partiendo de una revisión bibliográfica del estado del arte, para posteriormente ser modificada y validada por grupos de discusión conformados por expertos en competencias y formación docente. Los resultados de identificación de dichas competencias han sido finalmente refrendados mediante una encuesta respondida por una muestra representativa de la comunidad académica de las ocho universidades públicas catalanas. El objetivo fundamental del proyecto que aquí presentamos no es otro que el de contribuir a una formación de calidad del profesorado universitario, que permita la adquisición, desarrollo y evaluación de las competencias que, como docente, gran parte de la comunidad académica considera que debe poseer para el ejercicio de su labor profesional, definidas como: interpersonal, metodológica, comunicativa, de planificación y gestión de la docencia, de trabajo en equipo y de innovación.