Physiological and molecular predictors of cycling sprint performance.

The study aimed to identify novel muscle phenotypic factors that could determine sprint performance using linear regression models including the lean mass of the lower extremities (LLM), myosin heavy chain composition (MHC), and proteins and enzymes implicated in glycolytic and aerobic energy generation (citrate synthase, OXPHOS proteins), oxygen transport and diffusion (myoglobin), ROS sensing (Nrf2/Keap1), antioxidant enzymes, and proteins implicated in calcium handling. For this purpose, body composition (dual-energy X-ray absorptiometry) and sprint performance (isokinetic 30-s Wingate test: peak and mean power output, Wpeak and Wmean ) were measured in young physically active adults (51 males and 10 females), from which a resting muscle biopsy was obtained from the musculus vastus lateralis. Although females had a higher percentage of MHC I, SERCA2, pSer16 /Thr17 -phospholamban, and Calsequestrin 2 protein expressions (all p < 0.05), and 18.4% lower phosphofructokinase 1 protein expression than males (p < 0.05), both sexes had similar sprint performance when it was normalized to body weight or LLM. Multiple regression analysis showed that Wpeak could be predicted from LLM, SDHB, Keap1, and MHC II % (R 2 = 0.62, p < 0.001), each variable contributing to explain 46.4%, 6.3%, 4.4%, and 4.3% of the variance in Wpeak , respectively. LLM and MHC II % explained 67.5% and 2.1% of the variance in Wmean , respectively (R 2 = 0.70, p < 0.001). The present investigation shows that SDHB and Keap1, in addition to MHC II %, are relevant determinants of peak power output during sprinting.

Antioxidant enzymes and Nrf2/Keap1 in human skeletal muscle: Influence of age, sex, adiposity and aerobic fitness.

Ageing, a sedentary lifestyle, and obesity are associated with increased oxidative stress, while regular exercise is associated with an increased antioxidant capacity in trained skeletal muscles. Whether a higher aerobic fitness is associated with increased expression of antioxidant enzymes and their regulatory factors in skeletal muscle remains unknown. Although oestrogens could promote a higher antioxidant capacity in females, it remains unknown whether a sex dimorphism exists in humans regarding the antioxidant capacity of skeletal muscle. Thus, the aim was to determine the protein expression levels of the antioxidant enzymes SOD1, SOD2, catalase and glutathione reductase (GR) and their regulatory factors Nrf2 and Keap1 in 189 volunteers (120 males and 69 females) to establish whether sex differences exist and how age, VO2max and adiposity influence these. For this purpose, vastus lateralis muscle biopsies were obtained in all participants under resting and unstressed conditions. No significant sex differences in Nrf2, Keap1, SOD1, SOD2, catalase and GR protein expression levels were observed after accounting for VO2max, age and adiposity differences. Multiple regression analysis indicates that the VO2max in mL.kg LLM-1.min-1can be predicted from the levels of SOD2, Total Nrf2 and Keap1 (R = 0.58, P < 0.001), with SOD2 being the main predictor explaining 28 % of variance in VO2max, while Nrf2 and Keap1 explained each around 3 % of the variance. SOD1 protein expression increased with ageing in the whole group after accounting for differences in VO2max and body fat percentage. Overweight and obesity were associated with increased pSer40-Nrf2, pSer40-Nrf2/Total Nrf2 ratio and SOD1 protein expression levels after accounting for differences in age and VO2max. Overall, at the population level, higher aerobic fitness is associated with increased basal expression of muscle antioxidant enzymes, which may explain some of the benefits of regular exercise.

Determinants of the maximal functional reserve during repeated supramaximal exercise by humans: The roles of Nrf2/Keap1, antioxidant proteins, muscle phenotype and oxygenation.

When high-intensity exercise is performed until exhaustion a "functional reserve" (FR) or capacity to produce power at the same level or higher than reached at exhaustion exists at task failure, which could be related to reactive oxygen and nitrogen species (RONS)-sensing and counteracting mechanisms. Nonetheless, the magnitude of this FR remains unknown. Repeated bouts of supramaximal exercise at 120% of VO2max interspaced with 20s recovery periods with full ischaemia were used to determine the maximal FR. Then, we determined which muscle phenotypic features could account for the variability in functional reserve in humans. Exercise performance, cardiorespiratory variables, oxygen deficit, and brain and muscle oxygenation (near-infrared spectroscopy) were measured, and resting muscle biopsies were obtained from 43 young healthy adults (30 males). Males and females had similar aerobic (VO2max per kg of lower extremities lean mass (LLM): 166.7 ± 17.1 and 166.1 ± 15.6 ml kg LLM-1.min-1, P = 0.84) and anaerobic fitness (similar performance in the Wingate test and maximal accumulated oxygen deficit when normalized to LLM). The maximal FR was similar in males and females when normalized to LLM (1.84 ± 0.50 and 2.05 ± 0.59 kJ kg LLM-1, in males and females, respectively, P = 0.218). This FR depends on an obligatory component relying on a reserve in glycolytic capacity and a putative component generated by oxidative phosphorylation. The aerobic component depends on brain oxygenation and phenotypic features of the skeletal muscles implicated in calcium handling (SERCA1 and 2 protein expression), oxygen transport and diffusion (myoglobin) and redox regulation (Keap1). The glycolytic component can be predicted by the protein expression levels of pSer40-Nrf2, the maximal accumulated oxygen deficit and the protein expression levels of SOD1. Thus, an increased capacity to modulate the expression of antioxidant proteins involved in RONS handling and calcium homeostasis may be critical for performance during high-intensity exercise in humans.

Seroepidemiology Study of Porcine Epidemic Diarrhea Virus in Mexico by Indirect Enzyme-Linked Immunosorbent Assay Based on a Recombinant Fragment of N-Terminus Domain Spike Protein.

Porcine epidemic diarrhea (PED) is an intestinal disease caused by the porcine epidemic diarrhea virus (PEDV) and affects Mexico's swine industry. Despite the disease initially being described in Mexico in 2013, there has been no research into the virus's seroepidemiology carried out in Mexico. Thus, the goal of this study was to develop an indirect ELISA (iELISA) based on a recombinant N-terminal domain truncated spike (S) protein (rNTD-S) of PEDV to evaluate serum obtained from different pig-producing states in Mexico. A total of 1054 sera were collected from pig farms, slaughterhouses, and backyard production in the states of Aguascalientes, Guanajuato, Hidalgo, Jalisco, Morelos, Queretaro, Sinaloa, and Veracruz between 2019 and 2021. The rNTD-S protein was expressed in E. coli BL21 (DE3) cells. Negative and positive serum samples used in the iELISA were previously tested by Western blot. According to our findings, 61.66% of the serum samples (650/1054) were positive, with Jalisco having the highest percentage of positive samples, at a rate of 21.44% (226/1054). This is the first seroepidemiology study of PEDV carried out in Mexico, revealing that the virus is still circulating since the initial outbreak; furthermore, it provides an overview of PEDV's spread and high level of persistence across the country's key swine-producing states.

A Mango Leaf Extract (Zynamite®) Combined with Quercetin Has Exercise-Mimetic Properties in Human Skeletal Muscle.

Zynamite PX®, a mango leaf extract combined with quercetin, enhances exercise performance by unknown molecular mechanisms. Twenty-five volunteers were assigned to a control (17 males) or supplementation group (8 males, receiving 140 mg of Zynamite® + 140 mg quercetin/8 h for 2 days). Then, they performed incremental exercise to exhaustion (IE) followed by occlusion of the circulation in one leg for 60 s. Afterwards, the cuff was released, and a 30 s sprint was performed, followed by 90 s circulatory occlusion (same leg). Vastus lateralis muscle biopsies were obtained at baseline, 20 s after IE (occluded leg) and 10 s after Wingate (occluded leg), and bilaterally at 90 s and 30 min post exercise. Compared to the controls, the Zynamite PX® group showed increased basal protein expression of Thr287-CaMKIIδD (2-fold, p = 0.007) and Ser9-GSK3ß (1.3-fold, p = 0.005) and a non-significant increase of total NRF2 (1.7-fold, p = 0.099) and Ser40-NRF2 (1.2-fold, p = 0.061). In the controls, there was upregulation with exercise and recovery of total NRF2, catalase, glutathione reductase, and Thr287-CaMKIIδD (1.2-2.9-fold, all p < 0.05), which was not observed in the Zynamite PX® group. In conclusion, Zynamite PX® elicits muscle signaling changes in resting skeletal muscle resembling those described for exercise training and partly abrogates the stress kinases responses to exercise as observed in trained muscles.

Fast regulation of the NF-κB signalling pathway in human skeletal muscle revealed by high-intensity exercise and ischaemia at exhaustion: Role of oxygenation and metabolite accumulation.

The NF-κB signalling pathway plays a critical role in inflammation, immunity, cell proliferation, apoptosis, and muscle metabolism. NF-κB is activated by extracellular signals and intracellular changes in Ca2+, Pi, H+, metabolites and reactive oxygen and nitrogen species (RONS). However, it remains unknown how NF-κB signalling is activated during exercise and how metabolite accumulation and PO2 influence this process. Eleven active men performed incremental exercise to exhaustion (IE) in normoxia and hypoxia (PIO2:73 mmHg). Immediately after IE, the circulation of one leg was instantaneously occluded (300 mmHg). Muscle biopsies from m. vastus lateralis were taken before (Pre), and 10s (Post, occluded leg) and 60s after exercise from the occluded (Oc1m) and free circulation (FC1m) legs simultaneously together with femoral vein blood samples. NF-κB signalling was activated by exercise to exhaustion, with similar responses in normoxia and acute hypoxia, as reflected by the increase of p105, p50, IKKα, IκBß and glutathione reductase (GR) protein levels, and the activation of the main kinases implicated, particularly IKKα and CaMKII δD, while IKKß remained unchanged. Postexercise ischaemia maintained and stimulated further NF-κB signalling by impeding muscle reoxygenation. These changes were quickly reverted at the end of exercise when the muscles recovered with open circulation. Finally, we have shown that Thioredoxin 1 (Trx1) protein expression was reduced immediately after IE and after 1 min of occlusion while the protein expression levels of glutathione peroxidase 1 (Gpx1) and thioredoxin reductase 1 (TrxR1) remained unchanged. These novel data demonstrate that exercising to exhaustion activates NF-κB signalling in human skeletal muscle and regulates the expression levels of antioxidant enzymes in human skeletal muscle. The fast regulation of NF-κB at exercise cessation has implications for the interpretation of published studies and the design of new experiments.

Alteraciones de los mecanismos hemostáticos en niños operados del corazón / Alterations of hemosthasis in children operated of heart

Se estudiaron 20 niños postoperados del corazón, bajo circulación extracorpórea, que habían tenido pruebas de coagulación preoperatoria normales. Al ingresar a terapia intensiva, y 24 horas después, se les hicieron las siguientes determinaciones: hemoglobina (Hb), tiempo de protrombina (TP), tiempo parcial de tromboplastina (TPT), tiempo de trombina (TT), fibrinógeno, factores V, VIII y VIII/Von Willebrand, productos líticos de fibrina (PLF), cuenta y adhesividad plaquetaria, lisis de euglobulinas, plasminógeno y antitrombina III (ATIII). La Hb, FV y VIII, fibrinógeno, plaquetas, plasminógeno ATIII y adhesividad plaquetaria; el TP, TPT y TT, inicialmente alargados, se acortaron a las 24 horas, pero sin significación estadística. Los PLF fueron negativos en las dos ocasiones. En algunos pacientes se utilizó paquete globular, plasma frasco, vitamina K y concentrados plaquetarios. La prolongación del TP, TPT, y la disminución de la Hb, el fibrinógeno, el FV y la ATIII en el primer estudio fueron secundarios a la hemodilución, las plaquetas además disminuyen por daño físico. La adhesividad plaquetaria disminuida favorece el sangrado anormal. No se observó coagulación intravascular diseminada

Traumatismo craneoencefálico grave: complicaciones y manejo / Severe head injury: complications and treatment

Se revisaron 100 expedientes de niños con traumatismo craneoencefálico grave. Se analizó el sitio donde se presentó el accidente, la causa del accidente y las complicaciones observadas. La mayoría de los casos (77 por ciento) recibió tratamiento médico, el resto de ellos fueron intervenidos quirúrgicamente. Se comentan los hallazgos tomográficos. Treinta y seis pacientes quedaron con secuelas y 19 fallecieron

Evolución del tratamiento de la tuberculosis en Colombia / Evolution of the treatment of tuberculosis in Colombia

Con base en los artículos escritos por autores colombianos entre 1.901 y 1.976, se persiguió identificar el concepto de la Tuberculosis y su correlación con el tratamiento dado en cada una de las diferentes etapas de su evolución. Para ello, cada uno de los artículos fue reseñado y clasificado de acuerdo a su contenido en categorias así: diagnóstico, tratamiento, enfermedad general o mixto, para luego reclasificarlos según sus aportes, dando así las herramientas al análisis final. Durante el análisis se identificaron varios periodos internos no siempre hallándose correlación entre el concepto y el tratamiento antituberculoso. Además se encontró que el tratamiento es un reflejo del avance médico extranjero, el cual se copia y aplica en el medio colombiano

Insuficiencia renal aguda y estado de choque: comparación entre FENa y B2-m / Acute renal insufficiency and shock status: comparation between FENa and B2-m

Estudio de 53 lactantes con síndrome de choque e insuficiencia renal aguda, mediante "fracción excretada de sodio" y "excreción urinaria de Beta 2 microblogulina". La correlación entre estas dos pruebas para el diagnóstico de insuficiencia renal aguda fue muy significativa con r de Pearson de 0.79 y p menor de 0.01. Al correlacionar los hallazgos histopatológicos de insuficiencia renal aguda, en 10 pacientes que fallecieron, con la prueba fracción excretada de sodio y excreción de Beta 2 microglobulina en orina, mediante los índices de susceptibilidad, sensibilidad, valor pronóstico positivo, valor pronóstico negativo y eficacia, se demostró la mayor utilidad de Beta 2 microglobulina en relación con la fracción excretada de sodio para el diagnóstico de insuficiencia renal aguda en pacientes lactantes en estado de choque. Se puede concluir que ambas pruebas son eficaces para el diagnóstico de insuficiencia renal aguda, pero la Beta 2 microglobulina es más sensible, con un índice de confiabilidad de 95 a 99%

Sensibilidad in vitro de Pseudomonas aeruginosa / Sensibility in vitro of Pseudomonas aeruginosa

Al someter 148 cepas de Pseudomonas aeruginosa a agentes antimicrobianos de uso común, se determinó la concentración mínima inhibitoria. La mayor actividad sobre las cepas sometidas fue la de polimixina, sulfato de amikacina y tobramicina. El índice más alto de resistencia a tratamiento con ampicilina, cloramfenicol, nitrofurazona y estreptomicina correspondió a cepas aisladas de pacientes quemados

Evolución de la coagulación intravascular diseminada con microdosis de heparina / Course of disseminated intravascular coagulation with low doses of heparin

A 34 lactantes infectados graves se les midió tiempo de protrombina (TP), tiempo de tromboplastina parcial (TTP), plaquetas, fibrinógeno y productos líticos de fibrina (PLF). Todos se consideraron portadores de coagulación intravascular diseminada (CID). Se clasificaron en tres grupos: grupo I (6 pacientes) con fibrinógeno alto, plaquetas normales o altas y PLF elevados (considerado en fase de hipercoagulabilidad); grupo II (16 pacientes) con fibrinógeno normal, plaquetas bajas o normales y PLF elevados (en fase de compensación o "encubrimiento") y grupo III (12 pacientes) con fibrinógeno bajo, plaquetas bajas y PLF elevados (en fase de consumo). Después del tratamiento de fondo y utilización de heparina a 100 U/kg/24h, en infusión continua, se observó que en el grupo I el fibrinógeno, plaquetas y PLF disminuyeron a cifras normales; en el grupo II, el fibrinógeno y las plaquetas se mantuvieron normales y los PLF disminuyeron y en el grupo III, el fibrinógeno y las plaquetas se elevaron y los PLF disminuyeron. En los tres grupos el TP y TTP presentaron cambios sin importancia. Se concluye que la heparina en microdosis y a infusión continua frena la CID en cualquiera de las tres fases de evolución

Modificación de la renina en hipertensión arterial con la administración de captopril / Renine changes in arterial hypertension with captopril administration

Se estudiaron 18 pacientes hipertensos del servicio de nefrología pediátrica, con etiología renovascular o daño renal parenquimatoso, en quienes el control de las cifras de presión arterial fue difícil a pesar del tratamiento con varios antihipertensivos, decidiéndose administrar captopril. Se procesó renina antes y después de la administración del medicamento. Las muestras iniciales mostraron elevación de la renina por arriba de límites normales; posteriormente a la administración de captopril, dicha elevación se incrementó de manera considerable y la presión arterial disminuyó, lo cual implica que el sistema renina/angiotensina/aldosterona está relacionado con la génesis de la presión arterial alta de estos pacientes y que captopril lo bloquea en forma eficaz

Utilidad del captopril en hipertensión arterial relacionada con enfermedad renal / Usefulness of captopril in arterial hypertension related to renal disease

Se estudiaron 18 pacientes del servicio de nefrología pediátrica del Hospital General, Centro Médico "La Raza", con diagnóstico de hipertensión arterial renovascular o secundaria a daño parenquimatoso, en quienes el control de las cifras tensionales fue difícil con tratamiento combinado de varios medicamentos antihipertensivos. Se administró captopril en tres tomas durante treinta días; posteriormente las cifras tensionales disminuyeron de manera significativa, tanto para la presión sistólica como para la diastólica, lo que habla en favor del control eficaz de la hipertensión arterial con dicho farmaco, estableciéndose que el sistema renina/angiotensina/aldosterona está involucrado y que puede bloquearse con la administración de captopril