The Accessory Muscular Head of the Triceps Brachii Muscle with Tendinous Attachment / Cabeza Muscular Accesoria del Músculo Triceps Braquial con Inserción Tendinosa

SUMMARY: Variations in the triceps brachii muscle are uncommon, and especially limited reports exist on the accessory heads of tendinous origin that attach near the upper medial part of the humerus. During anatomical training at Nagasaki University School of Medicine, the accessory head of the triceps brachii muscle was observed on the right upper arm of a 72-year-old Japanese female. It arose tendinously from the medial side of the upper humerus, then formed a muscle belly and joined the distal side of the long head. This accessory head had independent nerve innervation, and the innervating nerve branched from a bundle of the radial nerve, which divided the nerve innervating the long head and the posterior brachial cutaneous nerve. The origin of the innervation of the accessory head was the basis for determining that this muscle head was an accessory muscle to the long head of the triceps brachii muscle. Embryologically, we discuss that part of the origin of the long head of the triceps brachii muscle was separated early in development by the axillary nerve and the posterior brachial circumflex artery, and it slipped into the surgical neck of the humerus and became fixed there. The accessory head crossed the radial nerve and deep brachial artery. When clinicians encounter compression of the radial nerve or profunda brachii artery, they should consider the presence of accessory muscles as a possible cause.

Las variaciones en el músculo tríceps braquial son poco comunes y existen informes especialmente limitados sobre las cabezas accesorias de origen tendinoso que se insertan cerca de la parte medial superior del húmero. Durante un entrenamiento anatómico en la Facultad de Medicina de la Universidad de Nagasaki, se observó la cabeza accesoria del músculo tríceps braquial en la parte superior del brazo derecho de una mujer japonesa de 72 años. Se originaba tendinosamente desde el lado medial de la parte superior del húmero, luego formaba un vientre muscular y se unía al lado distal de la cabeza larga. Esta cabeza accesoria tenía inervación nerviosa independiente, cuyo nervio se ramificaba a partir de un ramo del nervio radial, que dividía el nervio que inervaba la cabeza larga y el nervio cutáneo braquial posterior. El origen de la inervación de la cabeza accesoria fue la base para determinar que esta cabeza muscular era un músculo accesorio de la cabeza larga del músculo tríceps braquial. Embriológicamente, discutimos que parte del origen de la cabeza larga del músculo tríceps braquial se separó temprananamente en el desarrollo por el nervio axilar y la arteria circunfleja braquial posterior, y se deslizó hacia el cuello quirúrgico del húmero y quedó fijado allí. La cabeza accesoria cruzaba el nervio radial y la arteria braquial profunda. Cuando los médicos encuentran compresión del nervio radial o de la arteria braquial profunda, deben considerar la presencia de mús- culos accesorios como una posible causa.

Effect of Long-term Peripheral Nerve Stimulation on Neuro-Muscular Complex Morphologic Recovery in Experiment / Efecto de la Estimulación del Nervio Periférico a Largo Plazo sobre la Recuperación Morfológica del Complejo Neuromuscular en Experimento

SUMMARY: Peripheral nerve injury is an extremely important medical and socio-economic problem. It is far from a solution, despite on rapid development of technologies. To study the effect of long-term electrical stimulation of peripheral nerves, we used a domestically produced electrical stimulation system, which is approved for clinical use. The study was performed on 28 rabbits. Control of regeneration was carried out after 3 month with morphologic techniques. The use of long-term electrostimulation technology leads to an improvement in the results of the recovery of the nerve trunk after an injury, both directly at the site of damage, when stimulation begins in the early period, and indirectly, after the nerve fibers reach the effector muscle.

La lesión de los nervios periféricos es un problema médico y socioeconómico extremadamente importante. Sin embargo, y a pesar del rápido desarrollo de las tecnologías, aún no tiene solución. Para estudiar el efecto de la estimulación eléctrica a largo plazo de los nervios periféricos, utilizamos un sistema de estimulación eléctrica de producción nacional, que está aprobado para uso clínico. El estudio se realizó en 28 conejos. El control de la regeneración se realizó a los 3 meses con técnicas morfológicas. El uso de tecnología de electro estimulación a largo plazo conduce a una mejora en los resultados de la recuperación del tronco nervioso después de una lesión, tanto directamente en el lugar del daño, cuando la estimulación comienza en el período temprano, como indirectamente, después de que las fibras nerviosas alcanzan el músculo efector.

Confiabilidad Inter-evaluador en la Medición del Grosor Muscular y el Ángulo de Penación a través de la Evaluación Ecográfica: Estudio entre un Experto y un Kinesiólogo en Formación / Inter-Evaluator Reliability in Measurement of Muscle Thickness and Penance Angle through Ultrasound Evaluation: Comparison Study between an Expert and a Physical Therapist in Training

Existen diversas formas de evaluar el músculo esquelético. Una herramienta que ha ganado relevancia es la evaluación ecográfica. Esta, permite medir el grosor muscular (GM) y el ángulo de penación (AP). Por otra parte, en la formación inicial de los Kinesiólogos es importante realizar el ejercicio de la confiabilidad en la medición en relación al experto. un procedimiento diagnóstico. Así, el objetivo de este estudio es determinar la confiabilidad inter-evaluador en la medición del GM y el AP, a través de la evaluación ecográfica, entre un experto y un kinesiólogo en formación. La capacitación contó de tres fases; el ciclo teórico, el ciclo práctico y el proceso de confiabilidad. Para este último, se realizaron 10 pruebas para cada una de las mediciones GM 1, GM 2 y GM 3 y de AP. La confiabilidad inter-evaluador en la medición de GM es buena a excelente en los tres intentos GM1 (ICC=0,81; p=0,001), GM2 (ICC=0,86; p<0,001), GM3 (ICC=0,88;<0,001). Por su parte, la confiabilidad del AP fue pobre a regular (ICC=0,21; p=0,143. Las conclusiones de esta investigación indican que existe una excelente confiabilidad inter evaluador en la medición de GM. No así, en la medición de AP, por lo que se sugiere incrementar las horas prácticas en el proceso de aprendizaje de esta medida.

SUMMARY: Skeletal muscle can be assessed in a number of different ways. Consequently, ultrasound evaluation has become a relevant diagnostic tool. This procedure allows measuring muscle thickness (MT) and pennation angle (PA). Furthermore, during the initial training of physical therapists it is important in a diagnostic procedure, to exercise reliability in measurement in comparison to the expert. Therefore, the objective of this study is to determine the inter-rater reliability in the measurement of MT and PA, through ultrasound evaluation, between an expert and a physical therapist in training. This training was comprised of three phases: The theoretical cycle, the practical cycle and the reliability process. For the latter, ten different tests were performed for each of the MT 1, MT 2 and MT 3 and PA measurements. Inter-rater reliability in the MT measurement was good to excellent in the three attempts MT1 (ICC=0.81; p=0.001), MT2 (ICC=0.86; p<0.001), MT3 (ICC=0. 88;<0.001). On the other hand, reliability of the PA was poor to fair (ICC=0.21; p=0.143. In conclusion, this research indicates that there is excellent inter-rater reliability in the measurement of MT. This does not however apply to the measurement of PA. It is therefore suggested that practical hours during the learning process of this measure be increased.

Effect of M-wave Amplitude on Inter-evaluator Concordance and Number of Detected Innervation Zones in the Medial Gastrocnemius Using Multichannel Electromyography / Efecto de la Amplitud de la Onda M sobre la Concordancia entre Evaluadores y el Número de Zonas de Inervación Detectadas en el Gastrocnemio Medial Mediante Electromiografía Multicanal

SUMMARY: The Innervation Zones (IZ) correspond to clusters of neuromuscular junctions. The traditional method of locating IZs through voluntary muscle contractions may not be feasible in individuals with motor disorders. Imposed contractions by electrostimulation are an alternative. However, there is limited evidence regarding the factors that affect inter-evaluator concordance and the number of localized IZs when using imposed contraction. The main objective of this research was to determine the effect of the amplitude of compound motor action potentials (CMAPs) containing the M-wave on inter-evaluator agreement. As a secondary objective, was investigate the effect on the number of detected IZs. Twenty-four healthy volunteers (age: 21.2 ± 1.5years, weight: 67.4 ± 13.2kg, height: 1.68 ± 0.80m) participated in the study. Electrostimulation was applied to the tibial nerve to induce contraction of the medial gastrocnemius. The IZ were identified based on the M-wave recorded through multichannel electromyography. A receiver operating characteristic (ROC) analysis was conducted to assess sensitivity and specificity in detecting the IZs. Inter-rater agreement was evaluated using a two-way mixed effects test to determine the intraclass correlation coefficients (ICC). A p-value less than 0.05 was considered statistically significant. The ROC analysis revealed that for both evaluators, a specificity of 95% was achieved with an amplitude ≥30 %. The area under the ROC curve was 0.980 [0.964, 0.996], indicating a strong influence of CMAP amplitude on detection of IZs. The highest level of agreement (ICC = 0.788 [0.713, 0.844]) among the evaluators was observed with CMAP amplitudes equal to or greater than 80 % of the maximum M-wave. The findings of this study demonstrate that both the number and the inter-evaluator concordance for detecting IZs using imposed contractions are strongly influenced by the amplitude of the M-wave. Higher M-wave amplitudes were associated with improved concordance and increased IZ detection, making it crucial to standardize amplitude settings for reliable outcomes.

Las Zonas de Inervación (IZ) corresponden a grupos de uniones neuromusculares. El método tradicional para localizar IZs mediante contracciones musculares voluntarias puede no ser factible en personas con trastornos motores. Las contracciones impuestas mediante electro estimulación son una alternativa. Sin embargo, existe poca evidencia sobre los factores que afectan la concordancia entre evaluadores y el número de IZs localizadas al usar este tipo de contracciones. El objetivo de esta investigación fue determinar el efecto de la amplitud de los potenciales de acción motores compuestos (PAMCs) que contienen la onda M sobre la concordancia entre evaluadores. Como objetivo secundario, se investigó el efecto sobre el número de IZs detectadas. Veinticuatro voluntarios sanos (edad: 21.2 ± 1.5 años, peso: 67.4 ± 13.2 kg, altura: 1.68 ± 0.80 m) participaron en el estudio. Se aplicó electroestimulación al nervio tibial para inducir la contracción del gastrocnemio medial. Las IZs se identificaron según la onda M registrada mediante electromiografía multicanal. Se realizó un análisis de curva de las característica del receptor (ROC) para evaluar la sensibilidad y especificidad en la detección de las IZs. La concordancia entre evaluadores se evaluó utilizando una prueba de efectos mixtos de dos vías para determinar los coeficientes de correlación intraclase (ICC). Se consideró un valor de p menor que 0.05 como estadísticamente significativo. El análisis ROC reveló que para ambos evaluadores se logró una especificidad del 95% con una amplitud ≥30 %. El área bajo la curva ROC fue de 0.980 [0.964, 0.996], lo que indica una fuerte influencia de la amplitud del CMAP en la detección de las IZs. El nivel más alto de concordancia (ICC = 0.788 [0.713, 0.844]) entre los evaluadores se observó con amplitudes de CMAP iguales o mayores al 80 % de la onda M máxima. Los hallazgos de este estudio demuestran que tanto el número como la concordancia entre evaluadores para detectar IZs mediante contracciones impuestas están fuertemente influenciados por la amplitud de la onda M. Las amplitudes más altas de la onda M se asociaron con una concordancia mejorada y un aumento en la detección de IZs, lo que hace crucial estandarizar los ajustes de amplitud para obtener resultados confiables.

Variación Morfológica en la Musculatura Cefálica de Diplobatis ommata y Narcine vermiculatus (Chondrychthyes: Narcinidae) / Morphological Variation in the Cephalic Musculature of Diplobatis ommata and Narcine vermiculatus (Chondrychthyes: Narcinidae)

Los trabajos realizados sobre batoideos han demostrado que existen grandes variaciones en la musculatura de la región cefálica ventral, estos cambios están asociados a los diferentes estilos de vida de los organismos y por tanto, a los mecanismos de alimentación. El objetivo de este trabajo fue llevar a cabo un estudio comparativo de la morfología de la musculatura cefálica dorsal y ventral de dos especies de la familia Narcinidae: Narcine vermiculatus y Diplobatis ommata. Se observó que ambas especies comparten un patrón morfológico común. Los músculos que mostraron mayores variaciones en la región dorsal fueron el depresor rostral, el preorbital lateral y el elevador rostral. La diferencia más importante en esta región, entre ambas especies, fue la ausencia del músculo cucularis en D. ommata. En la región ventral las principales diferencias se observaron en los músculos depresor mandibular, preorbital medial, interbranquial y depresor hiomandibular. Este último músculo está formado por dos paquetes en D. ommata, en tanto que en N. vermiculatus por uno. Se puede concluir que la morfología de la musculatura cefálica es constante; sin embargo, se observan diferencias importantes en el grado de desarrollo de los músculos tanto en la región dorsal como en la ventral.

SUMMARY: Works conducted on batoids have revealed large variations in the musculature of the ventral cephalic region, associated to the different lifestyles of these organisms and, therefore, to their feeding mechanisms. This work aimed to conduct a comparative study of the dorsal and ventral cephalic muscular morphology of two species of the family Narcinidae: Narcine vermiculatus and Diplobatis ommata. It was observed that both species share a common morphological pattern. Muscles with larger variations in the dorsal region were the rostral depressor, the lateral preorbital and the rostral elevator. The most relevant difference in this region between both species was the absence of the cucularis muscle in D. ommata. In the ventral region, the main differences were observed in the mandibular depressor, medial preorbital, interbranchial and hyomandibular depressor muscles. In D. ommata, the latter is formed by two packages, and by one in N. vermiculatus. It can be concluded that the cephalic musculature is constant; however, significant differences are observed in the muscle development degree in both the dorsal and the ventral regions.

Dissectional Orientation: Morphological Variations of Teres Minor Muscle and its Nerve Supply

SUMMARY: The teres minor is one of the rotator cuff muscles that comprise the superior margin of the quadrangular space. Quadrangular space syndrome (QSS) refers to the entrapment or compression of the axillary nerve and the posterior humeral circumflex artery in the quadrangular space, often caused by injuries, dislocation of the shoulder joint, etc. Patients who fail the primary conservative treatments and have persistent symptoms and no pain relief for at least six months would be considered for surgical interventions for QSS. This cadaveric study of 17 cadavers (males: 9 and females: 8) was conducted in the Gross Anatomy Laboratory at the Department of Anatomy, Faculty of Medicine Siriraj Hospital, Mahidol University. The cadavers were preserved in a 10 % formaldehyde solution and obtained ethical approval by the ethical commission of the Siriraj Institutional Review Board. The morphology of the teres minor muscle-tendon junction, the bifurcation type of the axillary nerve, and the length and number of the terminal branches of the nerve to the teres minor were documented. Specimens with quadrangular space contents and surrounding muscles that had been destroyed were excluded from the study. The results showed that 47.06 % of the specimens had type A bifurcation, 47.06 % had type B bifurcation, and the remaining 5.88 % had type C bifurcation. It was observed that 58.82 % had nonclassic muscle-tendon morphology, while 41.18 % were classic. The average length of the terminal branches of the nerve to the teres minor in males was 1.13 cm, with the majority having two branches. For females, many showed one terminal branch with an average length of 0.97 cm. Understanding the differences in anatomical variations can allow for a personalized treatment plan prior to quadrangular space syndrome surgical procedures and improve the recovery of postsurgical interventions for patients.

El músculo redondo menor es uno de los músculos del manguito rotador que comprende el margen superior del espacio cuadrangular. El síndrome del espacio cuadrangular (QSS) se refiere al atrapamiento o compresión del nervio axilar y la arteria circunfleja humeral posterior en el espacio cuadrangular, a menudo causado por lesiones, dislocación de la articulación humeral, entre otros. En los pacientes en los que fracasan los tratamientos conservadores primarios y presentan síntomas persistentes y ningún alivio del dolor durante al menos seis meses se considerarían para intervenciones quirúrgicas para QSS. Este estudio cadavérico de 17 cadáveres (hombres: 9 y mujeres: 8) se llevó a cabo en el Laboratorio de Anatomía Macroscópica del Departamento de Anatomía de la Facultad de Medicina del Hospital Siriraj de la Universidad Mahidol. Los cadáveres se conservaron en una solución de formaldehído al 10 % y obtuvieron la aprobación ética de la comisión ética de la Junta de Revisión Institucional de Siriraj. Se documentó la morfología de la unión músculo-tendón del músculo redondo menor, el tipo de bifurcación del nervio axilar y la longitud y el número de las ramas terminales del nervio para el músculo redondo menor. Se excluyeron del estudio los especímenes con contenido de espacios cuadrangulares y músculos circundantes que habían sido destruidos. Los resultados mostraron que el 47,06 % de los especímenes presentó bifurcación tipo A, el 47,06 % una bifurcación tipo B y el 5,88 % restante una bifurcación tipo C. Se observó que el 58,82 % presentaba una morfología músculo-tendinosa no clásica, mientras que el 41,18 % era clásica. La longitud pmedia de los ramos terminales del nervio hasta el músculo redondo menor en los hombres era de 1,13 cm, y la mayoría tenía dos ramos. En el caso de las mujeres, mostraron un ramo terminal con una longitud promedio de 0,97 cm. Comprender las diferencias en las variaciones anatómicas puede permitir un plan de tratamiento personalizado antes de los procedimientos quirúrgicos del síndrome del espacio cuadrangular y mejorar la recupe- ración de las intervenciones posquirúrgicas de los pacientes.

Acute Distal Biceps Tendon Injury: Diagnosis and Treatment / Lesões agudas do tendão distal do bíceps: Diagnóstico e tratamento

Abstract Acute distal biceps injuries clinically present with sudden pain and acute loss of flexion and supination strength. The main injury mechanism occurs during the eccentric load of the biceps. The hook test is the most significant examination test, presenting the highest sensibility and specificity for this lesion. Magnetic resonance imaging, the gold standard imaging test, can provide information regarding integrity and identify partial and/or complete tears. The surgical treatment uses an anterior or double approach and several reattachment techniques. Although there is no clinical evidence to recommend one fixation method over the other, biomechanical studies show that the cortical button resists better to failure. Although surgical treatment led to an 89% rate of return to work in 14 weeks, the recovery of high sports performance occurred in 1 year, with unsustainable outcomes.

Resumo As lesões agudas do tendão distal do bíceps se apresentam, clinicamente, com uma dor súbita associada a perda aguda de força de flexão e supinação. Seu principal mecanismo de lesão ocorre durante contração excêntrica do bíceps. O "Hook Test" é o principal teste semiológico, sendo o mais sensível e específico. A ressonância magnética, exame padrão ouro para o diagnóstico, pode fornecer informações sobre a integridade, identificando as lesões parciais e/ou completas. O tratamento cirúrgico pode ser realizado por duas vias principais: anterior e por dupla via porém as técnicas de reinserção tendínea são diversas não havendo evidência clínica que recomende um método de fixação em detrimento ao outro; embora o botão cortical apresente maior resistência a falha nos estudos biomecânicos. Com o tratamento cirúrgico o retorno as atividades laborais foi de 89% em 14 semanas (média) porém ao esporte de alto rendimento o prazo foi longo, média de 1 ano, e não duradouro.

Morphological Classification of the Sagittal Tendon Plate in the Soleus Muscle in Japanese Cadavers / Clasificación Morfológica de la Lámina Tendinosa Sagital del Músculo Sóleo en Cadáveres Japoneses

SUMMARY: The human soleus muscle has attracted attention in the fields of sport science, rehabilitation medicine, etc. for improving exercise performance in training, preventing injuries, and rehabilitation. The sagittal tendon plate of the soleus muscle is particularly important in rehabilitation. Few studies, however, have evaluated the shape of the sagittal tendon plate in the human soleus muscle in detail and attempted to classify its variations based on its morphology. In this study, we conducted a detailed analysis of the morphology of the sagittal tendon plates in soleus muscle specimens from Japanese cadavers and constructed a morphology-based classification system and evaluated their frequencies of occurrence. First, the specimens were divided into those with a sagittal tendon plate that was visible on the anterior surface (pennate muscle group) and those without (non-pennate muscle group). Next, based on the "number" and "breadth" of the sagittal tendon plates, the pennate muscle group specimens were further classified into four classes: Class I (one tendon, thin), Class II (one tendon, slightly broad), Class III (one tendon, very broad), and Class IV (two tendons, thin). Subsequently, the specimens were further divided into three types based on the position where the sagittal tendon plate joined the Achilles tendon: median tendon type, lateral tendon type, and medial tendon type (a total 13 divisions). When 458 Japanese soleus muscle specimens were classified into these divisions, the occurrence frequencies of Class I-IV were 80.57 %, 4.59 %, 5.46 %, and 1.09 %, respectively. In Class I, the median tendon type was more frequent than the lateral and medial tendon types, accounting for 48.47 % overall. The classification types of the sagittal tendon plate and their respective occurrence frequencies shown in this study are expected to serve as fundamental data in implementing rehabilitation of soleus muscle.

El músculo sóleo humano ha atraído la atención de la ciencia del deporte, la medicina de rehabilitación, etc. para mejorar el rendimiento del ejercicio en el entrenamiento, prevenir las lesiones y rehabilitación. La lámina tendinosa sagital del músculo sóleo es particularmente importante en la rehabilitación. Sin embargo, pocos estudios han evaluado en detalle la forma de la placa lámina sagital en el músculo sóleo humano y han intentado clasificar sus variaciones en función de su morfología. Realizamos un análisis detallado de la morfología de las láminas de los tendones sagitales en muestras de músculo sóleo de cadáveres japoneses y construimos un sistema de clasificación basado en la morfología y, además, evaluamos su frecuencia de aparición. Los especímenes se dividieron en aquellos con una lámina de tendón sagital que era visible en la superficie anterior (grupo muscular pennado) y aquellos sin (grupo muscular no pennado). A continuación, según el "número" y el "ancho" de las láminas de los tendones sagitales, las muestras del grupo de músculos pennados se clasificaron en cuatro clases: Clase I (un tendón, delgado), Clase II (un tendón, ligeramente ancho), Clase III (un tendón, muy ancho) y Clase IV (dos tendones delgados). Posteriormente, las muestras se dividieron en tres tipos, según la posición donde la lámina del tendón sagital se unía al tendón calcáneo: tipo de tendón mediano, tipo de tendón lateral y tipo de tendón medial (un total de 13 divisiones). En estas divisiones se clasificaron 458 especímenes de músculo sóleo de indiviuos japoneses, las frecuencias de ocurrencia de Clase I-IV fueron 80,57 %, 4,59 %, 5,46 % y 1,09 %, respectivamente. En la Clase I, el tipo de tendón mediano era más frecuente que los tipos de tendón lateral y medial, representando el 48,47 % del total. Se espera que los tipos de clasificación de la lámina del tendón sagital y sus respectivas frecuencias de aparición, que se reportan en este estudio, sirvan como datos fundamentales para implementar la rehabilitación del músculo sóleo.

Asociación entre la Arquitectura Muscular y el Índice de Calidad Muscular en Adultos Sedentarios / Association Between Muscle Architecture and Muscle Quality Index in Sedentary Adults

La evaluación de la calidad y la arquitectura muscular son importantes para comprender y cuantificar los cambios musculares asociados con el envejecimiento y el estilo de vida sedentario, además nos facilita información de la capacidad del músculo para generar fuerza, potencia o funcionalidad. los objetivos del estudio fueron (I) determinar la asociación entre los parámetros de la arquitectura muscular y el índice de calidad muscular (MQI) y (II) determinar la asociación entre los parámetros de la arquitectura muscular y la potencia media relativa del sit to stand test (STS). Únicamente el grosor muscular (MT) mostró una asociación moderada con el MQI (r = 0,545). En contraste, tanto la longitud del fascículo (FL) como el ángulo de penación (PA) exhibieron asociaciones "muy bajas", las cuales no resultaron significativas con el MQI. Al examinar la relación de los parámetros de la arquitectura muscular con la potencia media relativa de STS, MT presentó una asociación "moderada" (r = 0,444). Sin embargo, tanto FL como PA mostraron asociaciones "muy bajas" y "bajas", respectivamente, con la potencia media relativa al STS. En conclusión, estos hallazgos refuerzan la idea de que MT puede ser un indicador relevante de la calidad muscular y la capacidad de generar potencia en la prueba de STS. Específicamente, se observó que un aumento en MT estaba asociado con una mejora en MQI y la potencia media relativa de STS.

SUMMARY: Assessment of muscle quality and architecture is important for understanding and quantifying muscle changes associated with aging and a sedentary lifestyle and provides information on the muscle's ability to generate strength, power, or function. The aims of the study were (I) to determine the association between muscle architecture parameters and muscle quality index (MQI) and (II) to determine the association between muscle architecture parameters and mean relative power in the sit-to-stand test (STS). Only muscle thickness (MT) showed a moderate association with MQI (r = 0.545). In contrast, both fascicle length (FL) and penile angle (PA) exhibited "very low" associations, which were not significant with the MQI. When examining the relationship between muscle architecture parameters and mean relative STS power, MT presented a "moderate" association (r = 0.444). However, both LF and PA showed "very low" and "low" associations, respectively, with a mean power relative to STS. In conclusion, these findings reinforce the idea that MT may be a relevant indicator of muscle quality and ability to generate power in the STS test. Specifically, an increase in MT was associated with an improvement in MQI and mean power relative to STS.

Predictive factors of the contracture test for diagnosing malignant hyperthermia in a Brazilian population sample: a retrospective observational study

Abstract Introduction Malignant Hyperthermia (MH) is a pharmacogenetic, hereditary and autosomal dominant syndrome triggered by halogenates/succinylcholine. The In Vitro Contracture Test (IVCT) is the gold standard diagnostic test for MH, and it evaluates abnormal skeletal muscle reactions of susceptible individuals (earlier/greater contracture) when exposed to caffeine/halothane. MH susceptibility episodes and IVCT seem to be related to individual features. Objective To assess variables that correlate with IVCT in Brazilian patients referred for MH investigation due to a history of personal/family MH. Methods We examined IVCTs of 80 patients investigated for MH between 2004‒2019. We recorded clinical data (age, sex, presence of muscle weakness or myopathy with muscle biopsy showing cores, genetic evaluation, IVCT result) and IVCT features (initial and final maximum contraction, caffeine/halothane concentration triggering contracture of 0.2g, contracture at caffeine concentration of 2 and 32 mmoL and at 2% halothane, and contraction after 100 Hz stimulation). Results Mean age of the sample was 35±13.3 years, and most of the subjects were female (n=43 or 54%) and MH susceptible (60%). Of the 20 subjects undergoing genetic investigation, 65% showed variants in RYR1/CACNA1S genes. We found no difference between the positive and negative IVCT groups regarding age, sex, number of probands, presence of muscle weakness or myopathy with muscle biopsy showing cores. Regression analysis revealed that the best predictors of positive IVCT were male sex (+12%), absence of muscle weakness (+20%), and personal MH background (+17%). Conclusions Positive IVCT results have been correlated to male probands, in accordance with early publications. Furthermore, normal muscle strength has been confirmed as a significant predictor of positive IVCT while investigating suspected MH cases.

Influence of probe position in the measurement of muscle thickness and its association with lean mass: an ultrasound study / Influencia de la posición de la sonda en la medición del grosor muscular y su asociación con la masa magra: un estudio ecográfico

SUMMARY: Skeletal muscles play a fundamental role in people's lives and their evaluation provides significant information on health. Different tools have been used to evaluate muscle mass, and the evaluation of muscle thickness (MT) using ultrasound has been included as an alternative, which can be performed with the probe in different positions; however, these could present differences. The objectives of this study were to determine whether there are differences in the measurement of MT in the vastus lateralis (VL) muscle using the probe in the longitudinal or transverse position, and to determine its association with the lean mass of the lower limbs. The results indicated no significant differences between MT measurements with the probe in the longitudinal and transverse positions (p =0.084). However, when associating these measurements with lower limb lean mass, it was found that transverse measurements had a strong association (r =0.547; p < 0.001), while longitudinal measurements had a moderate association (r =0.351; p =0.007). This suggests that measurements with the probe positioned transversely to measure the MT would be the best option. Therefore, it could be useful as an indicator of lower limb lean mass in the absence of tools, such as bioelectrical bioimpedance or magnetic nuclear resonance.

El músculo esquelético cumple un rol fundamental en la vida de las personas, y su evaluación entrega mucha información de la salud. Se han utilizado diferentes herramientas para evaluar la masa muscular, y el último tiempo se ha incluido la evaluación del grosor muscular (MT) a través de la ecografía como una alternativa para estimarla, las cuales se pueden realizar con la sonda en distintas posiciones, sin embargo, estas podrían presentar diferencias. Los objetivos del estudio fueron determinar si existen diferencias en la medición de MT en el músculo vasto lateral (VL) utilizando la sonda en posición longitudinal o transversal y determinar su asociación con la masa magra de los miembros inferiores. Los resultados indican que no existen diferencias significativas entre las mediciones de MT con la sonda en posición longitudinal y transversal (valor p: 0.084). Sin embargo, al asociar estas mediciones con la masa magra de los miembros inferiores, se encontró que las mediciones transversales poseen una asociación fuerte (r: 0.547; valor p < 0.001), mientras que las mediciones longitudinales presentan una asociación moderada (r: 0.351; valor p: 0.007). Esto sugiere que las mediciones con la sonda posicionada transversal para medir MT serían la mejor opción. Por lo tanto, podría ser de utilidad como un indicador de masa magra de los miembros inferiores en caso de no contar con herramientas como la bioimpedancia bioeléctrica o resonancia nuclear magnética.

High-intensity interval training (treadmill) effects in myokines and endoplasmic reticulum stress of calf muscles in obese mice / Efectos del entrenamiento interválico de alta intensidad (trotadora) en miocinas y estrés del retículo endoplasmático de los músculos surales en ratones obesos

SUMMARY: Obesity is commonly associated with chronic tissue inflammation and skeletal muscle dysfunction. The study aimed to investigate the effects of High-Intensity Interval training (HIIT) on myokines and endoplasmic reticulum (ER) stress of diet- induced obese (DIO) mice. Three-month-old C57BL/6 male mice were fed a control (C) diet (n=20) or a high-fat (HF) diet (n=20) for 16 weeks. Then, half of the groups underwent HIIT (treadmill running) for an additional four weeks. HIIT increased calf muscles' contribution to BW (+24 %) and reduced weight gain in HF/HIIT than in HF (-120 %). Intramuscular fat accumulation was observed in HF and HF/ HIIT. Peak velocity was higher in HF/HIIT compared to HF (+26 %). Plasma insulin did not change, but glycemia was lower in HF/HIIT than in HF (-30 %). Fndc5 (+418 %) and Irisin (+72 %) were higher in HF/HIIT than in HF. Muscle Fgf21 was higher in HF/HIIT compared to HF (+30 %). In addition, NfKb (-53 %) and Tnfa (-63 %) were lower in HF/HIIT than in HF. However, Il1b (-86 %), Il6 (- 48 %), Il7 (-76 %), and Il15 (-21 %) were lower in HF/HIIT than in HF. Finally, HIIT reduced ER stress in HF/HIIT compared to HF: Atf4, -61 %; Chop, -61 %; Gadd45, -95 %. In conclusion, HIIT leads to weight loss and avoids muscle depletion. HIIT improves blood glucose, Irisin-Fndc5, and peak velocity. In addition, HIIT mitigates muscle inflammation and ER stress.

La obesidad es asociada comúnmente con inflamación tisular crónica y disfunción del músculo esquelético. El estudio tuvo como objetivo investigar los efectos del entrenamiento de intervalos de alta intensidad (HIIT) en las mioquinas y el estrés del retículo endoplásmico (ER) de ratones obesos inducidos por dieta (DIO). Se alimentó a ratones macho C57BL/6 de tres meses de edad con una dieta control (C) (n=20) o una dieta rica en grasas (HF) (n=20) durante 16 semanas. Luego, la mitad de los grupos se sometieron a HIIT (carrera en una trotadora) durante cuatro semanas más. HIIT aumentó la contribución de los músculos de la pantorrilla al BW (+24 %) y redujo el aumento de peso en HF/HIIT en HF (-120 %). Se observó acumulación de grasa intramuscular en HF y HF/HIIT. La velocidad máxima fue mayor en HF/HIIT en comparación con HF (+26 %). La insulina plasmática no cambió, pero la glucemia fue menor en HF/HIIT que en HF (-30 %). Fndc5 (+418 %) e Irisin (+72 %) fueron mayores en HF/HIIT que en HF. El Fgf21 muscular fue mayor en HF/ HIIT en comparación con HF (+30 %). Además, NfKb (-53 %) y Tnfa (-63 %) fueron menores en HF/HIIT que en HF. Sin embar- go, Il1b (-86 %), Il6 (-48 %), Il7 (-76 %) e Il15 (-21 %) fueron más bajos en HF/HIIT que en HF. Finalmente, HIIT redujo el estrés de RE en HF/HIIT en comparación con HF: Atf4, -61 %; Picar, - 61 %; Gadd45, -95 %. En conclusión, HIIT conduce a la pérdida de peso y evita el agotamiento muscular. HIIT mejora la glucosa en sangre, Irisin-Fndc5 y la velocidad máxima. Además, HIIT mitiga la inflamación muscular y el estrés ER.

Anticoncepção oral e hipotrofia muscular: existe correlação? / Oral contraception and muscle atrophy: is there a correlation?

As pílulas anticoncepcionais consistem na formulação combinada de um estrogênio e um progestagênio ou em apresentações simples de progestagênio isolado com a finalidade de bloquear a ovulação e alterar as condições do útero e das tubas uterinas, bloqueando parcialmente a foliculogênese e a inibição do pico de gonadotrofinas. Desse modo, no que concerne à temática, diversas publicações na mídia de ampla divulgação afirmam que os anticoncepcionais orais têm papel importante na sarcopenia e na hipotrofia, incluindo perda de força muscular e redução do desempenho físico. Assim, o presente trabalho tem por objetivo avaliar, por meio de pesquisas de artigos, a correlação entre anticoncepcionais hormonais orais e hipotrofia muscular. Foi concluído que os artigos científicos especializados no tema são ainda bastante inconclusivos, sugerindo que há indicações de que usuárias de anticoncepcional oral sejam mais suscetíveis ao dano muscular induzido por exercícios, contudo ainda não há consenso.

Anticonception pills consist of a combined formulation of an estrogen and a progestogen or simple presentations of progestogen alone with the purpose of blocking ovulation and altering the conditions of the uterus and uterine tubes, partially blocking folliculogenesis and inhibiting the gonadotropin peak. Thus, with regard to the subject, several widely publicized media publications claim that oral contraceptives play an important role in sarcopenia and hypotrophy, including loss of muscle strength and reduced physical performance. So, the present work aims to evaluate through article searches the correlation between oral hormonal contraceptives and muscle hypotrophy. It was concluded that scientific articles specialized on the subject are still quite inconclusive, suggesting that there are indications that oral contraceptive users are more susceptible to exercise-induced muscle damage, however there is still no consensus.

A rare variation of radial nerve coexisting with the intercalated ectopic muscle from latissimus dorsi muscle / Una rara variación del nervio radial que coexiste con el músculo ectópico intercalado del músculo latísimo del dorso

SUMMARY: The axilla is the main communication channel connecting the upper limbs, the neck and chest. Stabilization of the internal structure is essential for upper limb and shoulder mobility. In this case, we observed and recorded the characteristics of the variation of the radial nerve as well as the intercalated ectopic muscle from latissimus dorsi muscle. The position relationship between both, was also particularly noted by us. In view of the presence of the variation we reported, related clinical research, surgery and disease diagnosis are expected to take this case into account.

La axila es el principal canal de comunicación que conecta los miembros superiores, el cuello y el tórax. La estabilización de la estructura interna es fundamental para la movilidad del miembro superior y del hombro. En este caso observamos y registramos las características de la variación del nervio radial así como del músculo ectópico intercalado del músculo latísimo del dorso. La relación de posición entre ambas también fue significativa en este estudio. En vista de la presencia de la variación que informamos, se espera que la investigación clínica relacionada con la cirugía y el diagnóstico de la enfermedad tengan en cuenta este caso.

iPSCs ameliorate hypoxia-induced autophagy and atrophy in C2C12 myotubes via the AMPK/ULK1 pathway

BACKGROUND: Duchenne muscular dystrophy (DMD) is an X-linked lethal genetic disorder for which there is no effective treatment. Previous studies have shown that stem cell transplantation into mdx mice can promote muscle regeneration and improve muscle function, however, the specific molecular mechanisms remain unclear. DMD suffers varying degrees of hypoxic damage during disease progression. This study aimed to investigate whether induced pluripotent stem cells (iPSCs) have protective effects against hypoxia-induced skeletal muscle injury. RESULTS: In this study, we co-cultured iPSCs with C2C12 myoblasts using a Transwell nested system and placed them in a DG250 anaerobic workstation for oxygen deprivation for 24 h. We found that iPSCs reduced the levels of lactate dehydrogenase and reactive oxygen species and downregulated the mRNA and protein levels of BAX/BCL2 and LC3II/ LC3I in hypoxia-induced C2C12 myoblasts. Meanwhile, iPSCs decreased the mRNA and protein levels of atrogin-1 and MuRF-1 and increased myotube width. Furthermore, iPSCs downregulated the phosphorylation of AMPKA and ULK1 in C2C12 myotubes exposed to hypoxic damage. CONCLUSIONS: Our study showed that iPSCs enhanced the resistance of C2C12 myoblasts to hypoxia and inhibited apoptosis and autophagy in the presence of oxidative stress. Further, iPSCs improved hypoxia-induced autophagy and atrophy of C2C12 myotubes through the AMPK/ULK1 pathway. This study may provide a new theoretical basis for the treatment of muscular dystrophy in stem cells.

NEDD4-1 deficiency impairs satellite cell function during skeletal muscle regeneration

BACKGROUND: Satellite cells are tissue-specific stem cells primarily responsible for the regenerative capacity of skeletal muscle. Satellite cell function and maintenance are regulated by extrinsic and intrinsic mechanisms, including the ubiquitin-proteasome system, which is key for maintaining protein homeostasis. In this context, it has been shown that ubiquitin-ligase NEDD4-1 targets the transcription factor PAX7 for proteasome-dependent degradation, promoting muscle differentiation in vitro. Nonetheless, whether NEDD4-1 is required for satellite cell function in regenerating muscle remains to be determined. RESULTS: Using conditional gene ablation, we show that NEDD4-1 loss, specifically in the satellite cell population, impairs muscle regeneration resulting in a significant reduction of whole-muscle size. At the cellular level, NEDD4-1-null muscle progenitors exhibit a significant decrease in the ability to proliferate and differentiate, contributing to the formation of myofibers with reduced diameter. CONCLUSIONS: These results indicate that NEDD4-1 expression is critical for proper muscle regeneration in vivo and suggest that it may control satellite cell function at multiple levels.

Cholic and deoxycholic acids induce mitochondrial dysfunction, impaired biogenesis and autophagic flux in skeletal muscle cells

BACKGROUND: Skeletal muscle is sensitive to bile acids (BA) because it expresses the TGR5 receptor for BA. Cholic (CA) and deoxycholic (DCA) acids induce a sarcopenia-like phenotype through TGR5-dependent mechanisms. Besides, a mouse model of cholestasis-induced sarcopenia was characterised by increased levels of serum BA and muscle weakness, alterations that are dependent on TGR5 expression. Mitochondrial alterations, such as decreased mitochondrial potential and oxygen consumption rate (OCR), increased mitochondrial reactive oxygen species (mtROS) and unbalanced biogenesis and mitophagy, have not been studied in BA-induced sarcopenia.METHODS: We evaluated the effects of DCA and CA on mitochondrial alterations in C2C12 myotubes and a mouse model of cholestasis-induced sarcopenia. We measured mitochondrial mass by TOM20 levels and mitochondrial DNA; ultrastructural alterations by transmission electronic microscopy; mitochondrial biogenesis by PGC-1α plasmid reporter activity and protein levels by western blot analysis; mitophagy by the co-localisation of the MitoTracker and LysoTracker fluorescent probes; mitochondrial potential by detecting the TMRE probe signal; protein levels of OXPHOS complexes and LC3B by western blot analysis; OCR by Seahorse measures; and mtROS by MitoSOX probe signals. RESULTS: DCA and CA caused a reduction in mitochondrial mass and decreased mitochondrial biogenesis. Interestingly, DCA and CA increased LC3II/LC3I ratio and decreased autophagic flux concordant with raised mitophagosome-like structures. In addition, DCA and CA decreased mitochondrial potential and reduced protein levels in OXPHOS complexes I and II. The results also demonstrated that DCA and CA decreased basal, ATP-linked, FCCP-induced maximal respiration and spare OCR. DCA and CA also reduced the number of cristae. In addition, DCA and CA increased the mtROS. In mice with cholestasis-induced sarcopenia, TOM20, OXPHOS complexes I, II and III, and OCR were diminished. Interestingly, the OCR and OXPHOS complexes were correlated with muscle strength and bile acid levels. CONCLUSION: Our results showed that DCA and CA decreased mitochondrial mass, possibly by reducing mitochondrial biogenesis, which affects mitochondrial function, thereby altering potential OCR and mtROS generation. Some mitochondrial alterations were also observed in a mouse model of cholestasis-induced sarcopenia characterised by increased levels of BA, such as DCA and CA.

Ursodeoxycholic acid induces sarcopenia associated with decreased protein synthesis and autophagic flux

BACKGROUND: Skeletal muscle generates force and movements and maintains posture. Under pathological conditions, muscle fibers suffer an imbalance in protein synthesis/degradation. This event causes muscle mass loss and decreased strength and muscle function, a syndrome known as sarcopenia. Recently, our laboratory described secondary sarcopenia in a chronic cholestatic liver disease (CCLD) mouse model. Interestingly, the administration of ursodeoxycholic acid (UDCA), a hydrophilic bile acid, is an effective therapy for cholestatic hepatic alterations. However, the effect of UDCA on skeletal muscle mass and functionality has never been evaluated, nor the possible involved mechanisms. METHODS: We assessed the ability of UDCA to generate sarcopenia in C57BL6 mice and develop a sarcopenic-like phenotype in C2C12 myotubes and isolated muscle fibers. In mice, we measured muscle strength by a grip strength test, muscle mass by bioimpedance and mass for specific muscles, and physical function by a treadmill test. We also detected the fiber's diameter and content of sarcomeric proteins. In C2C12 myotubes and/or isolated muscle fibers, we determined the diameter and troponin I level to validate the cellular effect. Moreover, to evaluate possible mechanisms, we detected puromycin incorporation, p70S6K, and 4EBP1 to evaluate protein synthesis and ULK1, LC3 I, and II protein levels to determine autophagic flux. The mitophagosome-like structures were detected by transmission electron microscopy. RESULTS: UDCA induced sarcopenia in healthy mice, evidenced by decreased strength, muscle mass, and physical function, with a decline in the fiber's diameter and the troponin I protein levels. In the C2C12 myotubes, we observed that UDCA caused a reduction in the diameter and content of MHC, troponin I, puromycin incorporation, and phosphorylated forms of p70S6K and 4EBP1. Further, we detected increased levels of phosphorylated ULK1, the LC3II/LC3I ratio, and the number of mitophagosome-like structures. These data suggest that UDCA induces a sarcopenic-like phenotype with decreased protein synthesis and autophagic flux. CONCLUSIONS: Our results indicate that UDCA induces sarcopenia in mice and sarcopenic-like features in C2C12 myotubes and/or isolated muscle fibers concomitantly with decreased protein synthesis and alterations in autophagic flux.

Efecto de la dieta CAF sobre la capacidad de EX4 de modular la expresión de marcadores proteicos de oxidación de ácidos grasos y termogénesis en músculo de ratones / Effect of the CAF diet on the ability of EX4 to modulate the expression of protein markers of fatty acid oxidation and thermogenesis in mouse muscle

El ambiente obesogénico promueve la obesidad al facilitar el acceso y consumo de una amplia variedad de alimentos palatables altos en calorías. La activación del receptor de GLP1 (GLP1R) reduce la ingesta de alimentos, enlentece el vaciamiento gástrico y promueve un balance energético negativo a través de su acción en distintos órganos como el músculo esquelético, disminuyendo así el peso corporal. La obesidad inducida por dieta alta en grasa disminuye el efecto anorexigénico de la administración sistémica vía intra-peritoneal de EX4 (agonista de GLP1R). Sin embargo, se desconoce si la exposición a un ambiente obesogénico previo a la manifestación de obesidad disminuye los efectos anorexigénicos de EX4 o un posible efecto de EX4 sobre marcadores de oxidación de ácidos grasos y termogénesis en músculo esquelético. El objetivo de esta investigación fue determinar el efecto a corto plazo de la dieta CAF, un modelo del ambiente obesogénico humano, sobre la capacidad de EX4 de reducir la ingesta y modular la expresión de marcadores proteicos de oxidación de ácidos grasos y termogénesis (CPT1 y UCP2) en músculo de ratones. Nuestros datos muestran que una inyección intraperitoneal de EX4 a ratones C57BL/6J alimentados con dieta CAF o dieta control durante 10 días no altera la ingesta calórica total, peso corporal, o la expresión de proteínas marcadoras de los procesos de beta-oxidación y de termogénesis (CPT1 y UCP2). Estos datos sugieren que protocolos alternativos de administración de EX4 son necesarios para observar los efectos fisiológicos de la activación de GLP1R.

The obesogenic environment promotes obesity by facilitating access to and consumption of a wide variety of palatable, high-calorie foods. Activation of the GLP1 receptor (GLP1R) reduces food intake, slows gastric emptying, and promotes a negative energy balance by acting on organs such as skeletal muscle, thus decreasing body weight. Obesity induced by a high-fat diet decreased the anorexigenic effect of intraperitoneal systemic administration of EX4 (GLP1R agonist). However, it is unknown whether exposure to an obesogenic environment before the manifestation of obesity diminishes the anorexigenic effects of EX4 or a possible effect of EX4 on markers of fatty acid oxidation and thermogenesis in skeletal muscle. This investigation aimed to determine the short-term effect of the CAF diet, a model of the human obesogenic environment, on the ability of EX4 to reduce intake and modulate the expression of protein markers of fatty acid oxidation and thermogenesis (CPT1 and UCP2) in mouse muscle. Our data show that intraperitoneal injection of EX4 to C57BL/6J mice fed CAF diet or control diet for ten days does not alter total caloric intake, body weight, or expression of proteins markers of beta-oxidation and thermogenesis processes (CPT1 and UCP2). These data suggest that alternative EX4 administration protocols are necessary to observe the physiological effects of GLP1R activation.

Enrichment of miR-17-5p enhances the protective effects of EPC-EXs on vascular and skeletal muscle injury in a diabetic hind limb ischemia model

BACKGROUND/AIMS: Diabetes mellitus (DM) is highly susceptible to diabetic hind limb ischemia (DHI). MicroRNA (MiR)-17-5p is downregulated in DM and plays a key role in vascular protection. Endothelial progenitor cell (EPC)-released exosomes (EPC-EXs) contribute to vascular protection and ischemic tissue repair by transferring their contained miRs to target cells. Here, we investigated whether miR-17-5p-enriched EPC-EXs (EPC-EXsmiR-17-5p) had conspicuous effects on protecting vascular and skeletal muscle in DHI in vitro and in vivo. METHODS: EPCs transfected with scrambled control or miR-17-5p mimics were used to generate EPC-EXs and EPC-EXsmiR-17-5p. Db/db mice were subjected to hind limb ischemia. After the surgery, EPC-EXs and EPC-EXsmiR-17-5p were injected into the gastrocnemius muscle of the hind limb once every 7 days for 3 weeks. Blood flow, microvessel density, capillary angiogenesis, gastrocnemius muscle weight, structure integrity, and apoptosis in the hind limb were assessed. Vascular endothelial cells (ECs) and myoblast cells (C2C12 cells) were subjected to hypoxia plus high glucose (HG) and cocultured with EPC-EXs and EPC-EXsmiR-17-5p. A bioinformatics assay was used to analyze the potential target gene of miR-17-5p, the levels of SPRED1, PI3K, phosphorylated Akt, cleaved caspase-9 and cleaved caspase-3 were measured, and a PI3K inhibitor (LY294002) was used for pathway analysis. RESULTS: In the DHI mouse model, miR-17-5p was markedly decreased in hind limb vessels and muscle tissues, and infusion of EPC-EXsmiR-17-5p was more effective than EPC-EXs in increasing miR-17-5p levels, blood flow, microvessel density, and capillary angiogenesis, as well as in promoting muscle weight, force production and structural integrity while reducing apoptosis in gastrocnemius muscle. In Hypoxia plus HG-injured ECs and C2C12 cells, we found that EPC-EXsmiR-17-5p could deliver their carried miR-17-5p into target ECs and C2C12 cells and subsequently downregulate the target protein SPRED1 while increasing the levels of PI3K and phosphorylated Akt. EPC-EXsmiR-17-5p were more effective than EPC-EXs in decreasing apoptosis and necrosis while increasing viability, migration, and tube formation in Hypoxia plus HG-injured ECs and in decreasing apoptosis while increasing viability and myotube formation in C2C12 cells. These effects of EPC-EXsmiR-17-5p could be abolished by a PI3K inhibitor (LY294002). CONCLUSION: Our results suggest that miR-17-5p promotes the beneficial effects of EPC-EXs on DHI by protecting vascular ECs and muscle cell functions.