Skeletal muscle contraction is reputed not to depend on extracellular Ca2+. Indeed, stricto sensu, excitation-contraction coupling does not necessitate entry of Ca2+. However, we previously observed that, during sustained activity (repeated contractions), entry of Ca2+ is needed to maintain force production. In the present study, we evaluated the possible involvement of the canonical transient receptor potential (TRPC)1 ion channel in this entry of Ca2+ and investigated its possible role in muscle function. Patch-clamp experiments reveal the presence of a small-conductance channel (13 pS) that is completely lost in adult fibers from TRPC1(-/-) mice. The influx of Ca2+ through TRPC1 channels represents a minor part of the entry of Ca(2+) into muscle fibers at rest, and the activity of the channel is not store dependent. The lack of TRPC1 does not affect intracellular Ca2+ concentration ([Ca2+](i)) transients reached during a single isometric contraction. However, the involvement of TRPC1-related Ca2+ entry is clearly emphasized in muscle fatigue. Indeed, muscles from TRPC1(-/-) mice stimulated repeatedly progressively display lower [Ca2+](i) transients than those observed in TRPC1(+/+) fibers, and they also present an accentuated progressive loss of force. Interestingly, muscles from TRPC1(-/-) mice display a smaller fiber cross-sectional area, generate less force per cross-sectional area, and contain less myofibrillar proteins than their controls. They do not present other signs of myopathy. In agreement with in vitro experiments, TRPC1(-/-) mice present an important decrease of endurance of physical activity. We conclude that TRPC1 ion channels modulate the entry of Ca(2+) during repeated contractions and help muscles to maintain their force during sustained repeated contractions.

The present study aimed at analyzing the technical and tactical aspects of professional padel matches in relation to gender and match outcome. For this purpose, a notational analysis was performed on 22 official matches of the World Padel Tour 2016 by means of 18 technical and tactical indicators. A non-parametric approach was applied to evaluate differences (P ≤ 0.05) between gender and match outcome subgroups. For gender, differences emerged for the occurrence (P<0.001) and duration (P<0.001) of rallies, backhand strokes (P=0.02) and backhand volley (P=0.027), strokes close to net (P=0.001) and from midfield zone (P=0.012), smashes determining ball out (P<0.001), and first service faults (P<0.001). For match outcome, a difference was found only for the occurrence of winning rallies (in general: P<0.001; in female performance: P=0.009; in male performance: P=0.001). Although findings highlight that padel performance can be discriminated only for gender, whereas winning and losing performances resulted similar, probably for the influence of different playing styles, this study could represent a valuable reference for further analyses and more effective padel training plans. El presente estudio tuvo como objetivo analizar aspectos técnicos y tácticos en pádel profesional en relación con el género y el resultado final del partido. Para ello, se realizó un análisis notacional de 22 partidos oficiales del circuito profesional World Padel Tour 2016 registrando 18 indicadores técnicos y tácticos. Se llevó a cabo un aná-lisis no paramétrico de los datos para comparar las diferencias (P ≤ 0.05) entre los subgrupos de género y resultado final. Para el género, se encontraron diferencias en el número (P<0.001) y duración (P<0.001) de los rallies, golpes de revés (P=0.02) y voleas de revés (P=0.027), golpes cerca de la red (P<0.001) y golpes desde la zona intermedia del campo (P=0.012), remates ganadores por bola fuera del campo (P<0.001) y faltas de primer saque (P<0.001). Para el resultado del partido, se encontraron diferencias únicamente en el número de rallies ganadores (en general: P<0.001; en mujeres: P=0.009; en hombres: P=0.001). Los resultados obtenidos ponen de manifiesto importantes diferencias en el rendimiento de pádel en cuanto al género, observando resultados similares entre ganadores y perdedores probablemente como consecuencia de diferentes estilos de juego. Este estudio por tanto puede servir como referencia válida para el desarrollo tanto de futuros análisis como de planes de entrenamiento más efectivos en pádel.Palabras clave: indicadores técnicos; indicadores tácticos; frecuencia cardiac; contramovimiento; prensión manual. Resumen

Objective: To ensure the safety and quality of vaccines, especially the newest RNA-vaccines against COVID-19, is one of the World Health Organization's current highest priorities. Design: Case description. Study sample: We report three cases of sudden unilateral tinnitus following BNT162b2 mRNA-vaccine injection, which rapidly resolved in 2 out of 3 cases. Results: The mechanism responsible for its development remains unclear. A hypersensitivity reaction with an abnormal autoimmune response or a vasculitic event may be implicated. Conclusions: Large-scale and well-designed studies are needed to improve surveillance of the COVID-19 vaccine and better define possible adverse reactions involving the cochleo-vestibular system and/or immunisation anxiety-related reactions.

The potential role of sonography in evaluating the response to therapy of persistent knee joint synovitis (KJS) was assessed in a longitudinal study in pre-and post-arthroscopic (AS) synovectomy in rheumatoid and psoriatic patients. At entry to the study ultrasound (US) detection of synovial proliferation was compared with arthroscopic visualization as the 'gold standard' reference. US joint effusion and synovial thickness measures and predominant patterns of synovial proliferation were recorded by comparing clinical and US indices before and at 2, 6 and 12 months after AS synovectomy, or after KJS relapse up to 24 months. A 12 month survival analysis of clinical and US outcomes of arthroscopic synovectomy was also performed. US detection of morphology and degree of synovial proliferation was correlated with AS macroscopic evaluation. After AS synovectomy, the clinical index and both US joint effusion and synovial thickness were significantly reduced, whereas US patterns of synovial proliferation did not show significant changes. US and clinical indices were significantly correlated in all follow-up measurements and US joint effusion was significantly increased in the relapsed compared with the non-relapsed KJS group. The probability at 12 months of reaching maximum improvement in US joint effusion and synovial thickness outcomes was 99 and 58%, respectively; that for clinical remission of KJS was 72%. Ultrasound evaluation has proven reliable and accurate by the arthroscopic gold standard in detecting changes of rheumatoid arthritis and psoriatic arthritis knee joint synovitis. The correlation of US with clinical findings in pre-and post synovectomy patients suggests that sonography can be used as an objective method in monitoring the response to therapy of inflammatory knee joint disease.

There have been a few studies that examined the oxidative stress effects of nicotine during pregnancy and lactation. The adverse effect of prenatal smoking exposure on human fetal development and growth has been a major public health issue. Active or passive smoking during pregnancy can result in a wide variety of adverse outcomes, including intrauterine growth retardation (IUGR), prematurity, stillbirth, and the sudden infant death syndrome. Smoking in pregnancy has also been associated with an increased risk of attention deficit and learning problems in childhood. Some studies argued that as a principal component of tobacco smoke, nicotine alone is responsible for the majority of negative reproductive outcomes. Nicotine and its major metabolite cotinine can cross the placental barrier. The level of nicotine in fetal tissues was found to be equal to or greater than the plasma nicotine level in the mothers. The oxidative stress induce by nicotine has been increasingly postulated as a major contributor to endothelial dysfunction. A large body of research has investigated the potential role of antioxidant nutrients in the prevention of endothelial dysfunction in women. Therefore, the present study was undertaken to assess the potential benefit of antioxidant supplementation on markers of placental oxidative stress in an in vitro model of endothelial dysfunction induced by nicotine, since it was previously found that nicotine is able to trigger the placental secretion of stress molecules. In this regard, we evaluated the effects of vitamin C, vitamin E and N-acetylcysteine (NAC), alone or in combination, in placental villi culture after exposure to nicotine. The effect of antioxidant nutrients on trophoblast cells proliferation and vitality was also evaluated. The results obtained suggest that in a patho-physiological condition, such as endothelial dysfunction induced by nicotine, the deleterious effect of reactive oxygen species may be counteracted by an antioxidant therapy, and there is the need to investigate the optimum dosing and timing of antioxidants administration, since an inappropriate antioxidant treatment in pregnant women may have deleterious consequences, reducing placental cells proliferation until to cell death.