The Evolution of Appendicular Muscles During the Fin-to-Limb Transition: Possible Insights Through Studies of Soft Tissues, a Perspective

The evolution of the appendages during the fin-to-limb transition has been extensively studied, yet the majority of studies focused on the skeleton and the fossil record. Whereas the evolution of the anatomy of the appendicular musculature has been studied, the changes in the muscular architecture during the fin-to-limb transition remain largely unstudied, yet may provide important new insights. The fin-to-limb transition is associated with the appearance of a new mode of locomotion and the associated shift from pectoral to pelvic dominance. Here, we propose ways to investigate this question and review data on muscle mass and muscle architecture of the pectoral and pelvic muscles in extant vertebrates. We explore whether changes in appendage type are associated with changes in the muscular architecture and the relative investment in different muscle groups. These preliminary data show a general increase in the muscle mass of the appendages relative to the body mass during the fin-to-limb transition. The locomotor shift suggested to occur during the fin-to-limb transition appears supported by our preliminary data since in “fish” the pectoral fins are heavier than the pelvic fins, whereas in tetrapods, the forelimb muscles are less developed than the hind limb muscles. Finally, a shift in the investment in different muscle groups with an increase of the contribution of the superficial groups in tetrapods compared to “fish” appears to take place. Our study highlights the potential of investigating quantitative features of the locomotor muscles, yet also demonstrates the lack of quantitative data allowing to test these ideas.

Therapeutic efficacy of Albendazole and Mefloquine alone or in combination against early and late stages of Trichinella spiralis infection in mice

Summary This study aimed to determine the effectiveness of mefl oquine alone or combined with albendazole in reduced doses against T. spiralis infection. One hundred and twenty albino mice were orally infected with 200 T. spiralis larvae/mouse. Drugs were administered during the enteral phase on days 1 to 3 and on the chronic phase on days 35 to 37 post-infection, and mice were sacrificed, respectively, at days 7 or 48 post-infection to count mature intestinal worms or encysted muscle larvae. The effect of the treatment on the histology of the target organs of each phase, intestine and diaphragm, was also evaluated. A signifi cant decrease in intestinal worms was found in all treated groups relative to the untreated control group at a peak of 93.7% in the combination albendazole-mefl oquine group. Results in all treated groups demonstrated a signifi cant decrease in muscle larvae relative to untreated control groups, achieving 86.2 % in the combined albendazole-mefl oquine group. There was a marked improvement in the intestinal and muscular architecture in all treated groups compared to the non-treated control group. Notably, the albendazole-mefl oquine group showed an almost complete recovery. The combined albendazole-mefl oquine low dose regimen had the highest effect on reducing parasite burden and restoring normal histological architecture.

Comportamiento de la arquitectura y flexibilidad muscular con el uso de kinesiotape en músculos gastrocnemios acortados en sujetos jóvenes: ensayo clínico randomizado (Behavior of muscle architecture and flexibility with the use of kinesiotape in shorten

Objetivo: Analizar los efectos del kinesiotape sobre la arquitectura y flexibilidad de los músculos gastrocnemios acortados en sujetos jóvenes durante tres días de aplicación. Método: Veinticinco jóvenes sedentarios con acortamiento del músculo gastrocnemio, fueron asignados aleatoriamente a un grupo experimental (GE=13) intervenido con KT durante 72 horas y a un grupo control (GC=12). Se evaluó la flexibilidad del gastrocnemio y del sóleo. La arquitectura muscular, representada en la longitud del fascículo, grosor y ángulo de penación muscular, fue evaluada con un ultrasonógrafo en Modo B en ambos grupos. Para determinar los efectos de KT, se aplicó una prueba t. Todos los análisis fueron con una significancia p<0.05. Resultados: ultrasonográficos mostraron un aumento significativo en la longitud del fascículo muscular (p=0.021), y una disminución en el grosor (p=0.037) y ángulo de penación (p=0.026) muscular post-intervención con KT en el GE. La flexibilidad de los músculos gastrocnemio y sóleo aumento frente a la aplicación del KT pero sin cambios significativos. No se presentaron diferencias en el análisis entre el GE y GC. Conclusión: La aplicación de KT en sujetos con acortamiento de gastrocnemio, permite una mejor flexibilidad muscular al tercer día de uso, favorecido, posiblemente, por una modificación en la arquitectura muscular. Abstract: Objetive: To analyze the effects of kinesiotape on the architecture and flexibility of shortened gastrocnemius muscles in young subjects during three days of application. Method: Twenty-five sedentary youth with shortening of the gastrocnemius muscle were randomly assigned to an experimental group (EG=13) intervened with KT for 72 hours and to a control group (CG=12). The flexibility of gastrocnemius and soleus was evaluated. The muscular architecture, represented in the length of the fascicle, thickness and angle of muscular pennation, was evaluated with a Mode B ultrasound in both groups. To determine the effects of KT, a t-test was applied. All analyzes were with a significance of p <0.05. Results: The ultrasonographic results showed a significant increase in the length of the muscular fascicle (p=0.021), and a decrease in the thickness (p=0.037) and pennation angle (p=0.026) post-intervention muscle with KT in the EG. The flexibility of the gastrocnemius and soleus muscles increased compared to the application of KT but without significant changes. There were no differences in the analysis between the EG and CG. Conclusion: The application of KT in subjects with shortening of gastrocnemius, allows a better muscular flexibility on the third day of use, possibly favored by a modification in the muscular architecture.

P5265Magnetic resonance multilayer assessment of strain in patients with heart failure

Introduction Muscular architecture of the heart is three dimensionally complex and contractility parameters vary widely. Cardiac magnetic resonance (CMR) feature tracking is a largely available and facile method to assess myocardial strain at different layers of the myocardium. Purpose Assessing and compare the myocardial longitudinal (GLS) and circumferential strain (GCS) at three distinct layers of the myocardium in patients with heart failure (HF). Methods 59 patients with a clinical diagnosis of HF who were post-hoc subdivided according to the measured EF and echo assessment of diastolic impairment into 3 groups, following ESC guidelines, were included: (1) patients with HF with preserved ejection fraction (HFpEF) where EF >50% and diastolic dysfunction (E/e' ratio) is present and plasma levels of natriuretic peptides are elevated, (2) patients with HF with mid-range ejection fraction (HFmrEF), where EF = 40–49% and similar additional criterias are present, (3) patients with HF with reduced ejection fraction (HFrEF) where EF <40%. Exclusion criteria: valvulopathy, arrhythmias, insufficient acquisition and artefacts. Results Strain values are the highest in the Endo− and progressively lower in the Myo− and Epi− layers with a gradient present in all groups but decreasing in HFmEF and further in HFrEF. GLS decrease with the severity of the disease in all 3 layers Normal > HFpEF > HFmrEF > HFrEF (Endo−: −23.0±3.5 vs −20.0±3.3 vs −16.4±2.2 vs −11.0±3.2, p<0.001, Myo−: −20.7±2.4 vs −17.5.0±2.6 vs −14.5±2.1 vs −9.6±2.7, p<0.001, Epi−: −15.7±1.9 vs −12.2±2.1 vs −10.6±2.3 vs −7.7±2.3, p<0.001) (Figure A), GCS is not different between the Normal and HFpEF (Endo−: −34.5±6.2 vs −33.9±5.7, p=0.51; Myo−: −21.9±3.8 vs −21.3±2.2, p=0.39; Epi−: −11.4±2.0 vs −10.9±2.3, p=0.54) but markedly lower in systolic HF groups Normal > HFmrEF > HFrEF (Endo−: −34.5±6.2 vs −20.0±4.2 vs −12.3±4.2, p<0.001; Myo−: −21.9±3.8 vs −13.0±3.4 vs −8.0±2.7, p<0.001; Epi−: −11.4±2.0 vs −7.9±2.3 vs −4.5±1.9) (Figure B). ROC analysis renders Endo− GCS (AUC=0.89) and respectively Endo− GLS (AUC=0.74) as optimal to detect contractile impairment in HF with Youden's thresholds of −20.2 for Endo− GLS and, respectively, −28.1 for Endo− GCS. Endo− GCS is not different between control and HFpEF and GLS impairment is present only inconstantly in HFpEF. Conclusions Feature tracking CMR successfully assess layer-specific myocardial strain and emerges as a powerful tool in functional stratification of patients with HF. Strain amplitude varies consistently throughout the myocardium and its quantification warrants careful standardization. Sub-endocardial strain values of strain are comparatively the highest and show most predictive power to detect contractile impairment. Underlying systolic impairment is present only in a subgroup of patients with HFpEF and only GLS and not the GCS is for this purpose a useful diagnostic tool.

Morphological variation inBlommersiapelvic shape coincides with muscular architecture and parallels genus phylogenetic evolution

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Improvement of Endurance of DMD Animal Model Using Natural Polyphenols

Duchenne muscular dystrophy (DMD), the most common form of muscular dystrophy, is characterized by muscular wasting caused by dystrophin deficiency that ultimately ends in force reduction and premature death. In addition to primary genetic defect, several mechanisms contribute to DMD pathogenesis. Recently, antioxidant supplementation was shown to be effective in the treatment of multiple diseases including muscular dystrophy. Different mechanisms were hypothesized such as reduced hydroxyl radicals, nuclear factor-κB deactivation, and NO protection from inactivation. Following these promising evidences, we investigated the effect of the administration of a mix of dietary natural polyphenols (ProAbe) on dystrophic mdx mice in terms of muscular architecture and functionality. We observed a reduction of muscle fibrosis deposition and myofiber necrosis together with an amelioration of vascularization. More importantly, the recovery of the morphological features of dystrophic muscle leads to an improvement of the endurance of treated dystrophic mice. Our data confirmed that ProAbe-based diet may represent a strategy to coadjuvate the treatment of DMD.