Muscle architecture Dotaz Zobrazit nápovědu
BACKGROUND AND OBJECTIVE: Physiological cross-sectional area (PCSA) of a muscle plays a significant role in determining the force contribution of muscle fascicles to skeletal movement. This parameter is typically calculated from the lengths of muscle fibres selectively sampled from the superficial layer of the muscle. However, recent studies have found that the length of fibres in the superficial layer often differs significantly (p < 0.5) from the length of fibres in the deep layer. As a result, PCSA estimation is inaccurate. In this paper, we propose a method to automatically reconstruct fibres in the whole volume of a muscle from those selectively sampled on the superficial layer. METHODS: The method performs a centripetal Catmull-Rom interpolation of the input fibres within the volume of a muscle represented by its 3D surface model, automatically distributing the fibres among multiple heads of the muscle and shortening the deep fibres to support large attachment areas with extremely acute angles. RESULTS: Our C++ implementation runs in a couple of seconds on commodity hardware providing realistic results for both artificial and real data sets we tested. CONCLUSIONS: The fibres produced by the method can be used directly to determine the personalised mechanical muscle functioning. Our implementation is publicly available for the researchers at https://mi.kiv.zcu.cz/.
- MeSH
- kosterní svalová vlákna fyziologie MeSH
- kosterní svaly anatomie a histologie MeSH
- lidé MeSH
- pohyb MeSH
- svalová kontrakce MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
This article concerns the development of myocardial architecture--crucial for contractile performance of the heart and its conduction system, essential for generation and coordinated spread of electrical activity. Topics discussed include molecular determination of cardiac phenotype (contractile and conducting), remodeling of ventricular wall architecture and its blood supply, and relation of trabecular compaction to noncompaction cardiomyopathy. Illustrated are the structure and function of the tubular heart, time course of trabecular compaction, and development of multilayered spiral systems of the compact layer.
- MeSH
- embryonální vývoj fyziologie MeSH
- financování organizované MeSH
- kardiomyocyty fyziologie MeSH
- kontrakce myokardu fyziologie MeSH
- lidé MeSH
- myokard MeSH
- převodní systém srdeční fyziologie MeSH
- remodelace komor fyziologie MeSH
- srdce - funkce komor MeSH
- srdce embryologie fyziologie růst a vývoj MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- přehledy MeSH
Acute changes in muscle architecture influenced by muscle swelling might be associated with chronic adaptations to resistance exercise, including skeletal muscle growth. Concentric (CON) and eccentric (ECC) muscle actions both play a role in hypertrophic processes, but the influence of each on acute indices of muscle swelling (i.e., muscle thickness (MT) and pennation angle (PA)) remains relatively unknown. Therefore, this study compared the acute changes in MT and PA in response to work-matched CON versus ECC isokinetic exercise. Twelve university-aged students performed 2 bouts of maximal isokinetic knee extensions at 120°·s-1 on the same day: 50 CON followed by a work-matched ECC bout (∼5000 J; 28 ± 5 reps) with the contralateral limb. Ultrasound images were captured from the middle and distal sites of the vastus lateralis before and immediately after each exercise bout. From these images, MT and PA were measured. Middle and distal MT (11% and 14%, respectively; p < 0.001) and middle PA (39%, p < 0.001) increased only after CON. In addition, changes in MT were strongly related to the amount of total work performed (r = 0.76) during CON. Our results suggest that when the workload is matched between CON and ECC muscle actions performed at a moderate velocity, CON actions seem to be a more potent stimulus for inducing acute changes in MT and PA.
- MeSH
- časové faktory MeSH
- čtyřhlavý sval stehenní diagnostické zobrazování fyziologie MeSH
- cvičení fyziologie MeSH
- fyziologická adaptace MeSH
- lidé MeSH
- mladý dospělý MeSH
- odporový trénink * MeSH
- svalová kontrakce * MeSH
- svalová síla - dynamometr MeSH
- svalová síla MeSH
- ultrasonografie MeSH
- Check Tag
- lidé MeSH
- mladý dospělý MeSH
- mužské pohlaví MeSH
- ženské pohlaví MeSH
- Publikační typ
- časopisecké články MeSH
- srovnávací studie MeSH
It is not well-understood how type 1 diabetes (T1DM) affects skeletal muscle histological phenotype, particularly capillarisation. This study aimed to analyze skeletal muscle myosin heavy chain (MyHC) fibre type changes and 3D capillary network characteristics in experimental T1DM mice. Female C57BL/6J-OlaHsd mice were categorized into streptozotocin (STZ)-induced diabetic (n = 12) and age-matched non-diabetic controls (n =12). The muscle fibre phenotype of the soleus, gluteus maximus, and gastrocnemius muscles were characterized based on the expression of MyHC isoforms, while capillaries of the gluteus maximus were assessed with immunofluorescence staining, confocal laser microscopy and 3D image analysis. STZ-induced diabetic mice exhibited elevated glucose levels, reduced body weight, and prolonged thermal latency, verifying the T1DM phenotype. In both T1DM and non-diabetic mice, the gluteus maximus and gastrocnemius muscles predominantly expressed fast-twitch type 2b fibers, with no significant differences noted. However, the soleus muscle in non-diabetic mice had a greater proportion of type 2a fibers and comparable type 1 fiber densities (26.2 ± 14.6% vs 21.9 ± 13.5%) relative to diabetic mice. T1DM mice showed reduced fiber diameters (P = 0.026), and the 3D capillary network analysis indicated a higher capillary length per muscle volume in the gluteus maximus of diabetic mice compared to controls (P < 0.05). Overall, T1DM induced significant changes in the skeletal muscle, including shifts in MyHC fibre types, decreased fibre diameters, and increased relative capillarisation, possibly due to muscle fibre atrophy. Our findings emphasize the superior detail provided by the 3D analytical method for characterizing skeletal muscle capillary architecture, highlighting caution in interpreting 2D data for capillary changes in T1DM.
- MeSH
- diabetes mellitus 1. typu metabolismus patologie MeSH
- experimentální diabetes mellitus * metabolismus patologie MeSH
- kapiláry * patologie metabolismus MeSH
- kosterní svaly * metabolismus patologie krevní zásobení MeSH
- myši inbrední C57BL MeSH
- myši MeSH
- streptozocin MeSH
- těžké řetězce myosinu * metabolismus MeSH
- zobrazování trojrozměrné MeSH
- zvířata MeSH
- Check Tag
- myši MeSH
- ženské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Loss of muscle mass of the lower limbs and of the spine extensors markedly impairs locomotor ability and spine stability in old age. In this study, we investigated whether 8 w of neuromuscular electrical stimulation (NMES) improves size and architecture of the lumbar multifidus (LM) and vastus lateralis (VL) along with locomotor ability in healthy older individuals. Eight volunteers (aged 65 ≥ years) performed NMES 3 times/week. Eight sex- and age-matched individuals served as controls. Functional tests (Timed Up and Go test (TUG) and Five Times Sit-to-Stand Test (FTSST)), VL muscle architecture (muscle thickness (MT), pennation angle (PA), and fiber length (FL)), along with VL cross-sectional area (CSA) and both sides of LM were measured before and after by ultrasound. By the end of the training period, MT and CSA of VL increased by 8.6% and 11.4%, respectively. No significant increases were observed in FL and PA. LM CSA increased by 5.6% (left) and 7.1% (right). Interestingly, all VL architectural parameters significantly decreased in the control group. The combined NMES had a large significant effect on TUG (r = 0.50, p = 0.046). These results extend previous findings on the hypertrophic effects of NMES training, suggesting to be a useful mean for combating age-related sarcopenia.
- Publikační typ
- časopisecké články MeSH
Fukutinopatie patří do skupiny α-dystroglykanopatií, autosomálně recesivně dědičných myopatií kosterního svalu s variabilním postižením srdce. Onemocnění bylo objeveno v Japonsku, kde se endemicky vyskytuje ve formě Fukuyamovy vrozené svalové dystrofie. Vzácně se však vyskytuje také v jiných zemích s odlišnou genetickou architekturou. Prezentujeme případ fukutinopatie diagnostikovaný u mladého muže českého původu s dilatační kardiomyopatií, elevací kreatinkinázy a frustními známkami myopatie kosterního svalu při neurologickém vyšetření. Celoexomová sekvenace identifikovala na jedné alele patogenní variantu fukutinu (FKTN) His172Leu, která při rozsáhlé deleci exonů 1-9 na druhé alele FKTN působila jako homozygotní varianta. Kardiální i neurologický stav pacienta zůstává po čtyřech letech sledování stabilní. Recentně byla u pacienta na magnetické rezonanci (MR) mozku náhodně zjištěna rozsáhlá epidermoidní cysta čtvrté komory s útlakem mozkového kmene vyžadující neurochirurgický zákrok, která by mohla zapadat do vývojových anomálií mozku pacientů s fukutinopatiemi. V kontextu tohoto vzácného onemocnění rozebíráme diagnostiku a léčbu kardiomyopatií doprovázených onemocněním kosterního svalu.
Fukutinopathy belongs to α-dystroglykanopathies, autosomal recessive inherited skeletal muscle myopathies with a variable cardiac involvement. The disease was discovered in Japan with endemic occurrence as Fukuyama congenital skeletal dystrophy. However, it can be rarely diagnosed also in other countries with a different genetic architecture. We present a case of fukutinopathy in a young male of Czech origin with dilated cardiomyopathy and elevation of creatine phosphokinase. Neurologic assessment revealed just borderline signs of skeletal muscle myopathy. Whole-exome sequencing revealed in one allele a pathogenic missense variant of fukutin (FKTN) His172Leu, which was accompanied by a large deletion of exons 1-9 in the second allele of FKTN acting as a homozygous variant. Cardiac and neurologic status of the patient remained stable in the last four years. Recently, the patient has been diagnosed with a large epidermoid cyst of the fourth brain chamber causing a brainstem compression, which required a neurosurgical intervention. The finding could be related to congenital cerebral abnormalities seen in patients with fukutinopathies. In the context of this rare disease, we discuss diagnostics and management of cardiomyopathies associated with a skeletal muscle myopathy.
- MeSH
- dilatační kardiomyopatie etnologie komplikace MeSH
- komorbidita MeSH
- lidé MeSH
- mladý dospělý MeSH
- muskuloskeletální nemoci prevence a kontrola MeSH
- svalové dystrofie etiologie komplikace MeSH
- syndrom Walker-Walburgové * komplikace MeSH
- vzácné nemoci MeSH
- Check Tag
- lidé MeSH
- mladý dospělý MeSH
- mužské pohlaví MeSH
- Publikační typ
- kazuistiky MeSH
- práce podpořená grantem MeSH
INTRODUCTION AND HYPOTHESIS: Injury of the levator ani muscle (LAM) is a significant risk factor for pelvic organ prolapse (POP). The puborectalis (PRM) and pubovisceral (PVM) subdivisions are level III vaginal support structures. The null hypothesis was that there is no significant difference in patterns of LAM subdivisions in healthy nulliparous women. Secondarily, we evaluated the presence of different LAM injury in a POP-symptomatic cohort. METHODS: This retrospective magnetic resonance imaging study included: 64 nulligravidae without any pelvic floor dysfunction (PFD) and 526 women of various parity with symptomatic POP. Primary outcome was PVM and PRM morphology on the axial planes: the attachment site on the pubic bone, and the visible separation/border between the PVM and PRM. The attachment was scored as "normal" or "abnormal". The "abnormal" attachment was divided in two types: "type I"-loss of the muscle substance, but preservation of the overall muscle architecture-and "type II"-muscle detachment from the pubic bone. RESULTS: The puboanal muscle (PAM) subdivision was evaluated as a representative part of the PVM. The PAM and PRM attachments and separation were distinguished in all asymptomatic nulliparae. PAM and PRM attachments did not significantly differ. POP group characteristics were parity 1.9 ± 0.8, instrumental delivery 5.6%, hysterectomy or POP surgery 60%, all Pelvic Organ Prolapse Quantification (POP-Q) stages, LAM defect 77.6% (PRM: 77.1%; PAM: 51.3%). Type I injuries were more frequent (PRM 54.7%; PAM 53.9%) compared with type II (PRM 29.4%; PAM 42.1%). CONCLUSIONS: A LAM defect was present in 77.6% of women with symptomatic POP. In PRM and PAM subdivisions type I injury was more frequent than type II.
- MeSH
- lidé MeSH
- magnetická rezonanční tomografie MeSH
- pánevní dno zranění MeSH
- prolaps pánevních orgánů * diagnostické zobrazování etiologie MeSH
- retrospektivní studie MeSH
- těhotenství MeSH
- vagina * diagnostické zobrazování MeSH
- Check Tag
- lidé MeSH
- těhotenství MeSH
- ženské pohlaví MeSH
- Publikační typ
- časopisecké články MeSH
BACKGROUND: Nowadays, there is a lack of consensus and high controversy about the most effective range of motion (ROM) to minimize the risk of injury and maximize the resistance training adaptations. OBJECTIVE: To conduct a systematic review and meta-analysis of the scientific evidence examining the effects of full and partial ROM resistance training interventions on neuromuscular, functional, and structural adaptations. METHODS: The original protocol (CRD42020160976) was prospectively registered in the PROSPERO database. Medline, Scopus, and Web of Science databases were searched to identify relevant articles from the earliest record up to and including March 2021. The RoB 2 and GRADE tools were used to judge the level of bias and quality of evidence. Meta-analyses were performed using robust variance estimation with small-sample corrections. RESULTS: Sixteen studies were finally included in the systematic review and meta-analyses. Full ROM training produced significantly greater adaptations than partial ROM on muscle strength (ES = 0.56, p = 0.004) and lower-limb hypertrophy (ES = 0.88, p = 0.027). Furthermore, although not statistically significant, changes in functional performance were maximized by the full ROM training (ES = 0.44, p = 0.186). Finally, no significant superiority of either ROM was found to produce changes in muscle thickness, pennation angle, and fascicle length (ES = 0.28, p = 0.226). CONCLUSION: Full ROM resistance training is more effective than partial ROM to maximize muscle strength and lower-limb muscle hypertrophy. Likewise, functional performance appears to be favored by the use of full ROM exercises. On the contrary, there are no large differences between the full and partial ROM interventions to generate changes in muscle architecture.
- MeSH
- fyziologická adaptace MeSH
- lidé MeSH
- odporový trénink metody MeSH
- rozsah kloubních pohybů fyziologie MeSH
- svalová síla fyziologie MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- metaanalýza MeSH
- systematický přehled MeSH
Podle poslední WHO/ISFC klasifi kace kardiomyopatií je HKM defi nována jako "hypertrofie levé a/nebo pravé komory, která je obvykle asymetrická a postihuje mezikomorové septum". Tato hypertrofie může postihnout kteroukoli část myokardu, ale nejčastěji je to septum komor, samostatně či spolu s přední či zadní stěnou. Pokud hypertrofie postihuje bazální (subaortální) část septa, toto se valovitě vyklenuje do výtokového traktu LK a zužuje jej - obstrukční HKM (25-30 % všech případů HKM). Charakteristickými histologickými rysy HKM jsou hypertrofi e myokardu, jeho abnormální architektura (disarray), intersticiální fibróza a přítomnost silnostěnných drobných intramyokardiálních arterií. Abnormální morfologie myokardu je patrná i na elektronmikroskopické úrovni. Význam endomyokardiální biopsie pro diagnózu HKM je nejednoznačný; jednak proto, že nejcharakterističtější histologický znak - disarray není pro HKM zcela specifi cký, jednak proto, že vzorky odebrané z povrchových vrstev septa komor nemusí disarray zastihnout.
According to the last WHO/ISFC classifi cation of cardiomyopathies, HCM is defi ned as "hypertrophy of the left and/ or right ventricle, which is usually asymmetric and involves the interventricular septum". This hypertrophy may affect any region of the myocardium, however, most aften it is the ventricular septum, either lone or together with the anterior or posterior free wall. If the hypertrophy involves the basal (subaortic) part of the septum, this bulges into the outfl ow tract, leading to its narrowing ? obstructive HCM (25-30 % of all cases of HCM). The characteristic histological features of HCM are hypertrophy of the heart muscle, its abnormal architecture (disarray), interstitial fi brosis, and presence of thick-walled small intramyocardial arteries. The abnormal myocardial architecture is noted also at the ultrastructural level. The value of endomyocardial biopsy for diagnosis of HCM is controversial; on one side, the most characteristic histological feature - the disarray is not entirely specifi c for HCM, on the other side, the samples obtained from the superfi cial layers of interventricular septum may not involve the disarray.
