Artículos de Investigación

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Chewing Index: A Pilot Trial to Measure Masticatory Effort
(2026)
Franco Marinelli
;
Camila Venegas-Ocampo
;
Josefa Alarcón-Apablaza
;
Rosemarie Schneider
;
Pablo Navarro
<jats:p>Background/Objectives: Population aging presents new challenges for achieving healthy aging. Edentulism is a condition that diminishes quality of life. Several studies have attempted to analyze the impact of edentulism on masticatory function either by evaluating the final stage of the food bolus or the masticatory process itself. The present study aims to develop a chewing index (Ci) based on chewing time, the number of cycles, and the muscular activity of the masseter and temporal muscles. Methods: Two groups (n = 10 each, 60–80 years old), one with functional dentition (21 or more teeth) (Group F) and one with complete denture wearers (Group D), were used. Participants were asked to chew a total of 36 food samples. The number of chewing cycles (N), chewing time (T), and bilateral activity of the masseter and anterior temporal muscles were recorded and quantified using the root mean square. This activity was normalized with respect to a 5 s maximum voluntary clenching (TMAV). A chewing index (Ci) was calculated using the equation Ci = N × V%¯ × T/TMAV, where V%¯ represents the average normalized activity of the four muscles. Results: Ci values ranged from 0 to 62 for Group F and 0 to 262 for Group D. For 15 out of the 36 food samples, Ci was higher in Group D than in Group F. Conclusions: The results of this study are consistent with previous research showing that complete denture wearers must chew for a longer time and perform a greater number of chewing cycles compared with subjects with functional dentition.</jats:p>
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Skin advanced glycation end-products do not predict pulmonary function trajectories in adults from the ILERVAS cohort
(2026)
Gerard Torres
;
Esther Gracia-Lavedan
;
Jessica González
;
Mario Henríquez-Beltrán
;
Adriano D. S. Targa
Advanced glycation end-products (AGEs) activate specific receptors (RAGE) promoting inflammation and oxidative stress. The lungs, with high RAGE expression, may be particularly susceptible to AGE-related injury. This study assessed whether baseline skin AGE levels, measured by skin autofluorescence (SAF), predict pulmonary function decline in middle-aged adults with cardiovascular risk factors. This ancillary analysis of the ILERVAS cohort included adults aged 45–70 years with cardiovascular risk factors but without diabetes or chronic kidney disease. Baseline data included demographics, lifestyle, and fasting blood tests. SAF was measured using AGE Reader™, and spirometry performed at baseline and after a median follow-up of 4 years. Associations between baseline SAF and annual declines in FEV1, FVC, and FEV1/FVC were analysed using adjusted models and generalized additive models, stratified by smoking status. Among 658 participants (median age 56 years, 48% female), median baseline SAF was 1.90 AU [1.60; 2.20]. Baseline lung function was preserved, with median FEV1, FVC and FEV1/FVC of 2795 mL [2270; 3,341], 3,525 mL [2870; 4300], and 78.6% [74.4; 82.8]. Annual declines were − 81.9 mL [− 120.6; − 43.3] for FEV1, − 99.6 mL [− 159.3; − 37.9] for FVC, and − 0.04% [− 0.85; 0.70] for FEV1/FVC. No significant associations were found between SAF and spirometry changes. Results were consistent across smoking subgroups. Baseline skin AGE levels did not predict pulmonary function decline over four years in middle-aged adults with cardiovascular risk factors. While SAF reflects cumulative AGE exposure, it has limited prognostic value for lung function in this population.
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Evaluation of Mandibular Border Movements and Mastication in Patients with Temporomandibular Disorders: A Pilot Study with 3D Electromagnetic Articulography and Surface Electromyography
(2025)
Camila Cerda
;
Franco Marinelli
;
Jarpa-Parra, Marcela
;
Pablo Navarro
;
Ramón Fuentes
Temporomandibular disorders (TMD) are characterized by pain and restricted functionality of the temporomandibular joint (TMJ). The objective of this study was to characterize the kinematic and electromyographic patterns of mandibular border movements and mastication in patients with different forms of TMD compared with healthy controls, through a simultaneous three-dimensional electromagnetic articulography (EMA-3D) and surface electromyography (sEMG) recording protocol. Sixteen participants were included and divided into three groups according to the TMD diagnosis (articular, muscular and mixed) and one healthy control group. Kinematic data were recorded using EMA-3D, and electromyographic activity of the masticatory muscles was assessed using sEMG. Variables analyzed included trajectories, areas, ranges, and electrical activity during mandibular border movements and mastication. Patients with TMD exhibited reduced movement trajectories but larger areas within the mandibular polygons, particularly in the frontal and sagittal planes. During mastication, the number of cycles was higher in the muscular group and lower in the healthy controls. Patients with TMD showed greater mean electromyographic activity, which could suggest compensatory muscle strain. The EMA-3D system provided an accurate threedimensional analysis, while sEMG captured detailed patterns of muscle activation and strain, that help better understand the neuromuscular alterations associated with TMD. Differentiation between TMD types (articular, muscular and mixed) for the study of its kinematic and electromyographic characteristics, is essential to improve diagnosis and treatment strategies. This study highlights the relevance of advanced tools such as EMA-3D and sEMG in the evaluation of TMD using a simultaneous recording protocol such as the one proposed in this study.
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Assessment of weekly workload in relation to match workload in U-21 football: Analysis of ten competition microcycles
(2025)
Football has experienced considerable technological and methodological advancenments, which have also influenced youth football. Currently, youth development faces the challenge of preparing players who can meet the rigorous demands of modern football. Objective: To assess and compare the internal and external training throughout the microcycle (MD-4 to MD-1) with the match-day load in under-21 players from a professional team. Method: Sixteen under-21 footballers from a Chilean professional club (age: 24.9 ± 4.2 years; height: 180.9 ± 6.3 cm; body mass: 78.5 ± 8.5 kg) were monitored over 10 official microcycles corresponding to the Fundación-Collahuasi youth football championship, organized by the Chilean Football Federation. Results: Large differences (p < 0.001 and η²p > 0.2) were found in all variables between the training days and match day. The highest external load occurred on match day, particularly in TD (10,087 ± 708 m), HSR (709 ± 316 m), and PL (130 ± 21.1 au). The highest weekly training loads were recorded on MD-3 and MD-2, while MD-1 showed significant reductions in all variables. Internal load was also highest on match day (RPE: 7.87 ± 1.54) compared to training sessions. Conclusion: There are significant differences in internal and external load throughout the competitive microcycle in under-21 footballers. MD-3 stands out as the highest-load training day, with values comparable to match day in most variables, positioning it as a key session in the weekly plan. In contrast, MD-1 consistently showed the lowest loads, confirming its role as a tapering day before competition.
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Ultrasonic agglomeration applied to Durvillea Antarctica and Arthrospira platensis flours: Effects on thermophysical properties, protein conformational changes and microstructure
(2025)
Daniela Rivera-Tobar
;
Mario Pérez-Won
;
Erick Jara-Quijada
;
Luis González-Cavieres
;
Gipsy Tabilo-Munizaga
The effects of ultrasonic agglomeration (UA) on the thermophysical and structural properties of matrices based on flours from Durvillaea antarctica and Arthrospira platensis were evaluated. UA was applied under power amplitudes, times, and cycles, optimizing the processing conditions in the agglomerated matrix. The elastic modulus increased significantly under optimal UA conditions, reaching 43.08 ± 1.93 N/m 2 amplitude, compared to 0.051 ± 0.10 N/m 2 at 90 % power at 70 % power amplitude. Fractrutability increased by more than 50 %, reaching values up to 931.89 ± 23.78 N (90 % power amplitude, 25 s, 3 cycles). The protein denaturation temperature increased to 134–139 ◦ C with UA, indicating increased thermal stability. FTIR analysis revealed a reduction in β-sheet content (from 70.9 ± 3.1 % to ~50–58 %) and an increase in α-helix structures, reflecting protein unfolding. UA is an alternative to be explored in the food industry, with potential application in the development of functional and sustainable foods.
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Description of intraoral pressures on sub-palatal space in young adult patients with normal occlusion
(2015)
Fuentes, Ramón
;
Engelke, Wilfried
;
Flores, Tania
;
Navarro, Pablo
;
Borie, Eduardo
Under normal conditions, the oral cavity presents a perfect system of equilibrium between teeth, soft tissues and tongue. The equilibrium of soft tissues forms a closed capsular matrix, generating differences with the atmospheric environment. This difference is known as intraoral pressure. Negative intraoral pressure is fundamental to the stabilization of the soft palate and tongue, reducing neuromuscular activity for the permeability of the respiratory tract. Thus, the aim of this study was to describe the variations of intraoral pressure of the sub-palatal space (SPS) under different physiological conditions and biofunctional phases. A case series was conducted with 20 individuals aged between 18 and 25. The intraoral pressures were measured through a system of cannulae connected to a digital pressure meter in the SPS during seven biofunctional phases. Descriptive statistics were used based on the mean and standard deviation. The data recorded pressure variations under physiological conditions, reaching 65 mbar as the intraoral peak in forced inspiration. In the swallowing phase, peaks reached -91.9 mbar. No pressure variations were recorded in terms of atmospheric changes with the mouth open and semi-open. The data obtained during the swallowing and forced inspiration phases indicated forced lingual activity. In the swallowing phase, the adequate position of the tongue creates negative intraoral pressure, which represents a fundamental mechanism for the physical stabilization of the soft palate. This information could contribute to subsequent research into the treatment of primary roncopathies.
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Deletion of the adenosine A2A receptor increases the survival rate in a mice model of polymicrobial sepsis
(2020)
Miguel Meriño
;
Sebastián San Martín
;
Pedro Sandaña
;
Kurt Herlitz
;
Claudio Aguayo
We aim to investigate the role of A2A receptor in peritonitis-related sepsis by injection of a fecal solution (FS) as a model of polymicrobial infection. C57/black J6 wild-type (WT) and A2A-deficient mice (A2AKO) were exposed to sepsis induced by intraperitoneal injection of a FS (FS-induced peritonitis) or instead was injected with saline buffer (Sham). Survival rate and sepsis score were measured upto48h.Thepresenceofbacteriaintissuehomogenates was analyzed. Telemetry and speckle laser Doppler were used for systemic blood pressure and peripheral blood perfusion analysis, respectively. Histological analysis and identification of active caspase 3 were performed in selected organs, including the liver. The survival rate of A2AKO mice exposed to FS-induced peritonitis was significantly higher, and the sepsis score was lower than their respective WT counterpart. Injection of FS increases (50 to 150 folds) the number of colonies forming units in the liver, kidney, blood, and lung in WT mice, while these effects were significantly attenuated in A2AKO mice exposed to FS-induced peritonitis. A significant reduction in both systolic and diastolic blood pressure, as well as in the peripheral perfusion was observed in WTand A2AKO miceexposed to FS-induced peritonitis. Although, these last effects were significantly attenuated in A2AKO mice. Histological analysis showed a large perivascular infiltration of polymorphonuclear in the liver of WT and A2AKO mice exposed to FS-induced peritonitis, but again, this effect was attenuated in A2AKO mice. Finally, high expression of active caspase 3 was found only in the liver of WT mice exposed to FS-induced peritonitis. The absence of the A2A receptor increases the survival rate in mice exposed to polymicrobial sepsis. This outcome was associated with both hemodynamic compensation and enhanced anti-bacterial response.
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Different Shoulder Exercises Affect the Activation of Deltoid Portions in Resistance-Trained Individuals
(2020)
Yuri A. C. Campos
;
Jeferson M. Vianna
;
Miller P. Guimarães
;
Jorge L. D. Oliveira
;
Claudio Hernández-Mosqueira
<jats:title>Abstract</jats:title> <jats:p>The aims of this study were to compare muscle activity of the anterior deltoid, medial deltoid, and posterior deltoid in the bench press, dumbbell fly, shoulder press, and lateral raise exercises. Thirteen men experienced in strength training volunteered for the study. Muscle activation was recorded during maximum isometric voluntary contraction (MVIC) for data normalization, and during one set of 12 repetitions with the load of 60% 1RM in all exercises proposed. One-way repeated-measures ANOVA with Bonferroni’s posthoc was applied using a 5% significance level. For anterior deltoid, the shoulder press (33.3% MVIC) presented a significantly higher level of activation when compared to other exercises. Also, no significant difference was found between the bench press (21.4% MVIC), lateral raise (21.2% MVIC), and dumbbell fly (18.8% MVIC). For the medial deltoid, the lateral raise (30.3% MVIC) and shoulder press (27.9% MVIC) presented a significantly higher level of activity than the bench press (5% MVIC) and dumbbell fly (3.4% MVIC). Besides, no significant difference was found between the bench press and the dumbbell fly. For the posterior deltoid, the lateral raise (24% MVIC) presented a significantly higher level of activation when compared to other exercises. For the posterior deltoid portion, the shoulder press (11.4% MVIC) was significantly more active than the bench press (3.5% MVIC) and dumbbell fly (2.5% MVIC). Moreover, no significant difference was found between the bench press and the dumbbell fly. In conclusion, the shoulder press and lateral raise exercises showed a higher level of muscle activation in the anterior deltoid and medial deltoid when compared to the bench press and dumbbell fly exercises.</jats:p>
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Effect of neuromuscular resistance training on the performance of 5-km runners
(2020)
Miller P. Guimarães
;
Yuri A.C. Campos
;
Hiago L.R. de Souza
;
Gaspar P. da Silva
;
Claudio Hernández-Mosqueira
<jats:p>The study aimed to identify the effect of a neuromuscular resistance training protocol (NRTP) on the performance of 5-km distance runners. This study included 18 male runners (age=29.3±3.2 years, fat percentage=11.3±2.6%, body height=1.77±.04 m, body mass=73.4±4.4 kg, time in 5 km=20.6±2.4 min, training years=4.3±0.7 years). First, volunteers were anthropometrically evaluated, and they performed one-repetition maximum (1RM) 45º leg press (LP) strength test. Second, they performed an incremental protocol in the 45º LP to acquire the electromyographic threshold. Third, they completed a 5-km time trial run (5 km basal). In the fourth session, they performed NRTP in LP. And fifth, the 5-km time trial run was performed at 30 min, 48 h, 96 h, and 144 h post the NRTP intervention. A significant decrease (p≤.05) was observed when baseline values were compared with post 30 min and post 48 h (p=.02 and p=.04, respectively). However, there were significant positive differences in performance (p=.04 for time) when baseline values and post 144 h were analyzed. Therefore, it is concluded that the NRTP can be used by 5-km distance runners to improve their performance with a break of one week between the intervention and test.</jats:p>
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Sensitivity analysis of a strongly-coupled human-based electromechanical cardiac model: Effect of mechanical parameters on physiologically relevant biomarkers
(2020)
F. Levrero-Florencio
;
F. Margara
;
E. Zacur
;
A. Bueno-Orovio
;
Z.J. Wang
The human heart beats as a result of multiscale nonlinear dynamics coupling subcellular to whole organ processes, achieving electrophysiologically-driven mechanical contraction. Computational cardiac modelling and simulation have achieved a great degree of maturity, both in terms of mathematical models of underlying biophysical processes and the development of simulation software. In this study, we present the detailed description of a human-based physiologically-based, and fully-coupled ventricular electromechanical modelling and simulation framework, and a sensitivity analysis focused on its mechanical properties. The biophysical detail of the model, from ionic to whole-organ, is crucial to enable future simulations of disease and drug action. Key novelties include the coupling of state-of-the-art human-based electrophysiology membrane kinetics, excitation–contraction and active contraction models, and the incorporation of a pre-stress model to allow for pre-stressing and pre-loading the ventricles in a dynamical regime. Through high performance computing simulations, we demonstrate that 50% to 200%−1000% variations in key parameters result in changes in clinically-relevant mechanical biomarkers ranging from diseased to healthy values in clinical studies. Furthermore mechanical biomarkers are primarily affected by only one or two parameters. Specifically, ejection fraction is dominated by the scaling parameter of the active tension model and its scaling parameter in the normal direction (kort 2); the end systolic pressure is dominated by the pressure at which the ejection phase is triggered (Pej) and the compliance of the Windkessel fluid model (C); and the longitudinal fractional shortening is dominated by the fibre angle (φ) and kort 2. The wall thickening does not seem to be clearly dominated by any of the considered input parameters.

Artículos de Investigación

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