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Thermoregulation and fluid balance during professional soccer competition in the heat
(2005-04) Aragón Vargas, Luis Fernando; Moncada Jiménez, José; Solera Herrera, Andrea; Hernández Elizondo, Jessenia; Barrenechea Coto, Álvaro José; Monge Alvarado, María de los Ángeles
Purpose: To evaluate initial hydration status, fluid balance, and core temperature changes during a regular season soccer game of the Costa Rica professional league. Methods: 18 starting male professional players (nine from each team, including both goalies) gave written informed consent to participate. Data were collected between 10.00 and 13.00h (approximately); the game started at 11.00h. Average environmental conditions were 34.9°C and 35.4% rh, for a WBGT heat stress index of 31.9°C. Upon arrival at the stadium, urine samples were collected and players were weighed nude. Fluid intake was monitored and urine production was collected from this point until players were weighed nude after the game. Core temperature (Tcore) was obtained before the game, at halftime, and at the end from disposable temperature sensors swallowed by the players 3 hours prior to the game. Data are mean±SD (range). Results: Initial urine specific gravity (USG) was 1.018±0.008 (1.003–1.036); seven players showed USG ≥ 1.020. Body mass (BM) loss was 2.58±0.88kg (1.08–4.17kg), equivalent to a dehydration of 3.38±1.11%BM (1.68–5.34%BM). Sweat loss was 4448±1216mL (2950–6224mL), while fluid intake totalled 1948±954mL (655–4288mL); only 82±119mL (0–512mL) of urine were collected. Tcore ≥ 39.0°C was registered in four players by halftime, in nine by game end. Conclusions: In spite of reasonably high fluid intakes, these players incurred significant dehydration during the game and thermoregulation was impaired. The problem was worse because several players arrived already dehydrated. To protect the physical integrity of the players, soccer competition should not be scheduled in these environmental conditions. Supported by the Gatorade Sports Science Institute and UCR-VI-245-A4-303.
Sympathetic activity and cardiovascular risk markers in non-diabetic and diabetic Mexican older adults
(2019-06) García Suarez, Patricia Concepción; Fonseca Viana, Rebeca Baptista; Rentería, Iván; Canton Martínez, Ermilo; Jiménez Maldonado, Alberto; Moncada Jiménez, José
Purpose: To compare the SNS activity and metabolic markers associated to CVD in type 2 diabetic (T2D) and non-diabetic (ND) Mexican older adults. Methods: Volunteers were 11 T2D (Age = 60.8 ± 5.2 yr., body mass index [BMI]= 29.9 ± 4.6 kg/m2) and 17 ND (Age = 64 ± 4.8 yr., BMI = 28.4 ± 4.1 kg/m2) older adults residing in Baja California, Mexico. Morning blood serum samples were collected after 8-h fasting following body composition analysis (InBody 770, Cerritos, CA). A 5-min resting ECG recording (BioRadio, Cleveland, OH) was used to analyze HRV. Time and frequency domain analysis were assessed with Kubios HRV 3.1 software (Kubios Oy, Finland). Results: Between-group differences were found on blood glucose (T2D = 171.9±91.6 vs. ND = 80.17±12.0mg/dL, p < 0.001), and triglycerides (T2D = 266.9±126.17 vs. ND = 60.54 ± 47.8mg/dL, p < 0.02). Non-significant between-group differences were found on cholesterol (T2D = 183.0±45.1 vs. ND = 180.9±29.7mg/dL, p = 0.88), HDLc (T2D = 60.54±55.8 vs. ND = 47.88±20.73mg/dL, p = 0.92) and LDLc levels (T2D = 84.4±44.6 vs. ND = 107.84±26.74mg/dL, p = 0.22). The HR (T2D = 72.6±11.5 vs. ND = 71.7±7.8bpm, p = 1.0), beat-to-beat intervals (RR) (T2D = 845.7±128.7 vs. ND = 843.7±93ms, p = 0.94), Root Mean Square of the Successive Differences (RMSSD) (T2D = 68.7±58.0 vs. ND = 45.6±31.2ms, p = 0.45) and relative successive beats with > 50ms of difference (pNN50) (T2D = 23.4±25.5 vs. ND = 9.7±13.7%, p = 0.32) were similar in both groups. High- (T2D = 48.14±24.64 vs. ND = 45.5±22.9n.u., p= 0.67) and Low-frequency (T2D = 51.7±24.5 vs. ND = 54.0±23.3n.u., p= 0.70) time domains and LF/HF ratio (T2D = 2.0±2.4 vs. ND = 2.4±3.0, p = 0.68) were similar in both groups. Conclusions: Diabetic conditions did not affect substantially SNS activity compared with non-diabetic condition in a sample of Mexican older adults.
A comprehensive review of hypotheses about the biological function of zearalenone, and a new hypothesis for the function of resorcylic and dihydroxyphenylacetic macrolactones in fungi
(2025-05-03) Viñas Meneses, María; Karlovsky, Petr
The special metabolite of Fusarium spp. zearalenone (ZEN) exerts estrogenic effects on mammals, stimulates plant growth, stimulates sexual development in fungi, and inhibits fungal growth. These activities inspired hypotheses about the biological function of ZEN. We briefly review the discovery of ZEN and its implications. The main subject of this review is a critical assessment of the hypotheses that ZEN is a fungal hormone, a plant hormone, a virulence factor, or a fungal defense metabolite. Conceptual and technical issues related to testing these hypotheses, such as inadequate analytical methods, confusion of incidental effects with biological functions, and lack of normalization, are illuminated. Based on these considerations, gene knockout experiments, and on the effects of biotic interactions on ZEN synthesis, we argue that ZEN is a defense metabolite protecting Fusarium spp. against mycoparasites and competitors. Similar reasoning and published data suggest that the Fusarium metabolite fusaristatin A fulfils the same function. Fungi produce many macrolactones of resorcylic acid (RALs) and dihydroxyphenylacetic acid (DHPLs) with properties similar to ZEN. Their widespread occurrence, antifungal activity, and further considerations prompt us to hypothesize that the fundamental function of fungal RALs and DHPLs lies in defense and interference competition.
Tissue damaging toxins in snake venoms: mechanisms of action, pathophysiology and treatment strategies
(2024-03-22) Bittenbinder, Mátyás A.; van Thiel, Jory; Cardoso, Ferrnanda C.; Casewell, Nicholas; Gutiérrez, José María; Kool, Jeroen; Vonk, Freek J.
Snakebite envenoming is an important public health issue responsible for mortality and severe morbidity. Where mortality is mainly caused by venom toxins that induce cardiovascular disturbances, neurotoxicity, and acute kidney injury, morbidity is caused by toxins that directly or indirectly destroy cells and degrade the extracellular matrix. These are referred to as ‘tissue-damaging toxins’ and have previously been classified in various ways, most of which are based on the tissues being affected (e.g., cardiotoxins, myotoxins). This categorisation, however, is primarily phenomenological and not mechanistic. In this review, we propose an alternative way of classifying cytotoxins based on their mechanistic effects rather than using a description that is organ- or tissue-based. The mechanisms of toxin-induced tissue damage and their clinical implications are discussed. This review contributes to our understanding of fundamental biological processes associated with snakebite envenoming, which may pave the way for a knowledge-based search for novel therapeutic options.
Envenenamiento ofídico en Costa Rica: logros y tareas pendientes
(2020-09-03) Gutiérrez, José María; Arias Rodríguez, Jazmín; Alape Girón, Alberto
Objetivo: efectuar un análisis de los logros en Costa Rica en cuanto al problema de los envenenamientos por mordeduras de serpientes, y señalar tareas pendientes para reducir aún más el impacto de esta patología.
Metodología: se efectuó una revisión de bibliografía relacionada con el estudio del envenenamiento ofídico en Costa Rica y con los avances efectuados en el tema, en el país. Paralelamente, se identificaron aspectos que requieren atención en el manejo de esta enfermedad tropical desatendida.
Conclusiones: desde las primeras décadas del siglo XX, se han realizado avances significativos en la comprensión y manejo del problema de los envenenamientos por mordedura de serpiente en Costa Rica. Se ha trabajado desde una visión integral que incluye: investigación científico-tecnológica, producción y distribución de antivenenos, esfuerzos en prevención, capacitación de las personas profesionales de la salud en el diagnóstico y tratamiento, y docencia de grado y posgrado en el tema.
El país ha asumido un papel de liderazgo a nivel internacional, tanto en el plano académico como en la provisión de antivenenos a muchos países. No obstante, aún quedan aspectos del problema que requieren nuevos esfuerzos en nuestro medio, sobre todo en lo referente a la atención de las consecuencias biomédicas, psicológicas, sociales y económicas que sufren las personas afectadas.
Descriptores: antivenenos, mordeduras de serpientes, venenos.