Browsing by Author "Mendoza, Laura"

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    Efects of eccentric, concentric and eccentric/concentric training on muscle function and mass, functional performance, cardiometabolic health, quality of life and molecular adaptations of skeletal muscle in COPD patients: a multicentre randomised trial
    (2022) Peñailillo, Luis; Valladares-Ide, Denisse; Jannas-Velas, Sebastián; Flores-Opazo, Marcelo; Jalón, Mauricio; Mendoza, Laura; Nuñez, Ingrid; Díaz Patiño, Orlando
    Background: Chronic obstructive pulmonary disease (COPD) is the third cause of death worldwide. COPD is char‑acterised by dyspnoea, limited exercise tolerance, and muscle dysfunction. Muscle dysfunction has been linked to dysregulation between muscle protein synthesis, myogenesis and degradation mechanisms. Conventional concentric cycling has been shown to improve several clinical outcomes and reduce muscle wasting in COPD patients. Eccentric cycling is a less explored exercise modality that allows higher training workloads imposing lower cardio-metabolic demand during exercise, which has shown to induce greater muscle mass and strength gains after training. Interestingly, the combination of eccentric and concentric cycling training has scarcely been explored. The molecular adaptations of skeletal muscle after exercise interventions in COPD have shown equivocal results. The mechanisms of muscle wasting in COPD and whether it can be reversed by exercise training are unclear. Therefore, this study aims two-fold: (1) to compare the efects of 12 weeks of eccentric (ECC), concentric (CONC), and combined eccentric/concentric (ECC/CONC) cycling training on muscle mass and function, cardiometabolic health, physical activity levels and quality of life in severe COPD patients; and (2) to examine the molecular adaptations regulating muscle growth after training, and whether they occur similarly in specifc muscle fbres (i.e., I, IIa and IIx). Methods: Study 1 will compare the efects of 12 weeks of CONC, ECC, versus ECC/CONC training on muscle mass and function, cardiometabolic health, levels of physical activity and quality of life of severe COPD patients using a multicentre randomised trial. Study 2 will investigate the efects of these training modalities on the molecular adaptations regulating muscle protein synthesis, myogenesis and muscle degradation in a subgroup of patients from Study 1. Changes in muscle fbres morphology, protein content, genes, and microRNA expression involved in skeletal muscle growth will be analysed in specifc fbre-type pools. Discussion: We aim to demonstrate that a combination of eccentric and concentric exercise could maximise the improvements in clinical outcomes and may be ideal for COPD patients. We also expect to unravel the molecular mechanisms underpinning muscle mass regulation after training in severe COPD patients.
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    Geological and geotechnical investigation of the seismic ground response characteristics in some urban and suburban sites in Chile exposed to large seismic threats
    (2022) Maringue, Jose; Mendoza, Laura; Saez, Esteban; Yanez, Gonzalo; Montalva, Gonzalo; Soto, Valeria; Ayala, Felipe; Perez-Estay, Nicolas; Figueroa, Ronny; Sepulveda, Natalia; Galvez, Carlos; Ramirez, Paola; Ovalle, Carlos
    The central area of Chile's Valparaiso Region has been classified as a seismic gap for a major earthquake, which makes it very important to understand the seismic hazard of the zone. Generally, seismic codes consider a qualitative classification of sites to estimate the possible damage in the case of an earthquake scenario. Estimating the values of acceleration could be very important to prevent damages and increase preparedness for these rare events. In this research, a qualitative and quantitative estimation of seismic hazard is performed in the study area (Valparaiso region between Papudo and San Antonio 32 degrees-34 degrees S). This is achieved through an integrated and relatively economical approach which considers the information from Geology, Geophysical experiments (Gravity and seismic methods), and Geotechnical analyses. The results of the geophysical survey and geology information allow dividing the zone into five site types through a new proposal of site classification that depends not only on the V-s30,V- but also on the sites predominant period (T-0), which is an innovation of this work for the Chilean code. The Peak Ground Acceleration (PGA) values in the study zone were estimated using a Ground Motion Predictive Equation developed for the Chilean subduction zone. Additionally, we consider three different seismic scenarios according to the history of events in Central Chile. The results of this quantitative analysis show PGA values up to 0.52 g for the median and 1.2 g for the 84th percentile of the scenarios. Overall, the highest accelerations (PGA) are in zones with low shear wave velocities (< 500 m/s), a long predominant period (> 0.4 s) and where geology establishes the presence of low stiffness soils. The comparison of response spectra from the model against records from 2010 Maule and 1985 Valparaiso earthquakes shows available models tend to overpredict the intensities.
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    Pedometers to enhance physical activity in COPD : a randomised controlled trial
    (2015) Mendoza, Laura; Horta, Paula; Espinoza, José; Aguilera, Miguel; Balmaceda, Nicolás; Castro, Ariel; Ruiz, Mauricio; Díaz Patiño, Orlando; Hopkinson, Nicholas S.
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    Programa de incentivo de la actividad física apoyado por contadores de pasos en la enfermedad pulmonar obstructiva cronica
    (2013) Mendoza, Laura; Espinoza, José; Aguilera, Miguel; Balmaceda, Nicolás; Horta, Paula; Ruiz, Mauricio; Czischke, Karen; Schonffeldt, P.; Agar, Vivianne; Díaz Patiño, Orlando Alberto; Barcos, Paula; Castro, Ariel; Hopkinson, Nicholas
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    The boundaries of mild chronic obstructive pulmonary disease (COPD): design of the searching clinical COPD onset (SOON) study
    (2017) Labarca, Gonzalo; Bustamante, Andrea; Valdivia Cabrera, Gonzalo; Díaz Montero, Rodrigo Aquiles; Huete, Isidro; Mac Nab, Paul; Mendoza, Laura; Leppe, Jaime; Lisboa Basualto, Carmen; Saldías Peñafiel, Fernando; Díaz, Orlando