- MeSH
- kosterní svalová vlákna fyziologie klasifikace patologie MeSH
- kosterní svaly * anatomie a histologie fyziologie inervace patofyziologie MeSH
- lidé MeSH
- myotonie etiologie patofyziologie MeSH
- nemoci svalů klasifikace patofyziologie MeSH
- svalové dystrofie klasifikace patofyziologie MeSH
- svalové křeče etiologie patofyziologie MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- přehledy MeSH
Cold exposure depolarizes cells in insects due to a reduced electrogenic ion transport and a gradual increase in extracellular K+ concentration ([K+]). Cold-induced depolarization is linked to cold injury in chill-susceptible insects, and the locust, Locusta migratoria, has been shown to improve cold tolerance following cold acclimation through depolarization resistance. Here we investigate how cold acclimation influences depolarization resistance and how this resistance relates to improved cold tolerance. To address this question, we investigated if cold acclimation affects the electrogenic transport capacity and/or the relative K+ permeability during cold exposure by measuring membrane potentials of warm- and cold-acclimated locusts in the presence and absence of ouabain (Na+-K+ pump blocker) or 4-aminopyridine (4-AP; voltage-gated K+ channel blocker). In addition, we compared the membrane lipid composition of muscle tissue from warm- and cold-acclimated locust and the abundance of a range transcripts related to ion transport and cell injury accumulation. We found that cold-acclimated locusts are depolarization resistant due to an elevated K+ permeability, facilitated by opening of 4-AP-sensitive K+ channels. In accordance, cold acclimation was associated with an increased abundance of Shaker transcripts (gene encoding 4-AP-sensitive voltage-gated K+ channels). Furthermore, we found that cold acclimation improved muscle cell viability following exposure to cold and hyperkalemia even when muscles were depolarized substantially. Thus cold acclimation confers resistance to depolarization by altering the relative ion permeability, but cold-acclimated locusts are also more tolerant to depolarization.
- MeSH
- 4-aminopyridin farmakologie MeSH
- aklimatizace účinky léků fyziologie MeSH
- kosterní svalová vlákna účinky léků fyziologie MeSH
- Locusta migratoria fyziologie MeSH
- membránové potenciály účinky léků fyziologie MeSH
- nízká teplota * MeSH
- ouabain farmakologie MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
The objective of the current study is to present data on the splitting of skeletal muscle fibers in C57BL/6NCrl mice. Skeletal muscles (m. rectus femoris (m. quadriceps femoris)) from 500 (250 female and 250 male) C57BL/6NCrl mice in the 16th week of life were sampled during autopsy and afterwards standardly histologically processed. Results show spontaneous skeletal muscle fiber splitting which is followed by skeletal muscle fiber regeneration. One solitary skeletal muscle fiber is split, or is in contact with few localized splitting skeletal muscle fibers. Part of the split skeletal muscular fiber is phagocytosed, but the remaining skeletal muscular fiber splits are merged into one regenerating skeletal muscle fiber. Nuclei move from the periphery to the regenerating skeletal muscle fiber center during this process. No differences were observed between female and male mice and the morphometry results document < 1 % skeletal muscle fiber splitting. If skeletal muscular fibers splitting occurs 5 % > of all skeletal muscular fibers, it is suggested to describe and calculate this in the final histopathological report.
- MeSH
- kosterní svalová vlákna cytologie fyziologie MeSH
- myši inbrední C57BL MeSH
- myši MeSH
- zvířata MeSH
- Check Tag
- mužské pohlaví MeSH
- myši MeSH
- ženské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
The aim of this study was to evaluate cell diversity by considering how Ca(2+) signaling has been adapted in skeletal muscle cell function. We characterized single C2C12 myoblasts through intracellular Ca(2+) signaling kinetics after exposure to specific drugs and calcium blockers using fast fluorescence microspectrofluorimetry followed by ATP effect analysis, which confirmed the expression of functional purinergic adenosine and P2 receptors. Further, we found that glutamate sensitivity of C2C12 cells was mediated by ionotropic glutamate receptors; on the other hand, most cells were responsive to cyclopiazonic acid, which inhibits the sarco-endoplasmic reticulum Ca(2+)-ATPase pump. These results suggest that C2C12 cells possess functional L- and P/Q-type voltage-operated Ca(2+) channels, ryanodine receptors and functional sarcoplasmic reticulumCa(2+) stores (typical for muscle cells), adenosine and P2 purinergic receptors, as well as ionotropic glutamate receptors. The evaluation of intracellular Ca(2+) signaling is a promising approach towards a better understanding and control of the physiopathological properties of myogenic cells that could be used as a predictive factor in the selection of optimal cells for scaffold recellularization or for tissue engineered constructs used in stem cell therapy.
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 study attempted to compare the muscle fiber morphological responses to dynamic electrical muscle stimulation (DEMS) and dynamic hydraulic stimulation (DHS) in rats under hindlimb suspension (HLS). DEMS at 1 Hz, 50 Hz and 100 Hz for 10 min/day, 5 days/week were introduced to the animals' right quadriceps. Static and 2 Hz DHS were introduced to the right tibiae of other animal groups on a "10 min on - 5 min off - 10 min on" loading regime for 5 days/week. In the end of the 4-week experiments, histological changes in the corresponding soleus, gastrocnemius and quadriceps of the stimulated sites were examined. Compared to age-matched, HLS led to muscle atrophy and strongly reduced muscle wet weights and averaged cross-sectional fiber areas. Among the tested DEMS frequencies, the averaged cross-sectional quadriceps fiber area in the 50 Hz group was 29 % larger than the 100 Hz group. In contrast, difference in the muscle fiber response to the static and 2 Hz DHS was not observed in either soleus or gastrocnemius. Muscle fiber morphological responses to the active DEMS was in a load frequency dependent manner under disuse condition. Relatively passive compressions, either via static or 2Hz DHS, were unable to induce any difference in the muscle fiber responses under functional disuse.
- MeSH
- elektrická stimulace metody MeSH
- kosterní svalová vlákna fyziologie MeSH
- krysa rodu rattus MeSH
- mechanický stres * MeSH
- náhodné rozdělení MeSH
- orgánové kultury - kultivační techniky MeSH
- potkani Sprague-Dawley MeSH
- svalová kontrakce fyziologie MeSH
- zadní končetina - imobilizace metody fyziologie MeSH
- zvířata MeSH
- Check Tag
- krysa rodu rattus MeSH
- ženské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- srovnávací studie MeSH
PURPOSE: The pathogenesis of adolescent idiopathic scoliosis (AIS) remains poorly understood. To date, potentially involved local changes in the deep paraspinal muscles still remain unknown. METHODS: Needle electromyography (EMG) and muscle biopsy of paraspinal muscles at convexity and concavity of the AIS main thoracic curve were performed in 25 subjects. In this group, EMG was performed in 16 AIS subjects (12 females, 12-27 years), muscle biopsy in 18 AIS subjects (15 females, 11-31 years) compared to 10 non-scoliotic controls (6 females, 12-55 years). Samples of muscle tissue were removed during corrective surgery and were examined histologically, enzyme histochemically and immunohistochemically. Both methods of EMG and muscle biopsy were performed in 9 subjects (7 women, 12-27 years). RESULTS: Right curve convexity was found in 24 AIS subjects. Amplitudes of motor unit action potentials (MUPs) were significantly increased on the AIS curve convexity versus concavity. Turns, duration and phases of MUPs were without any significant changes. In all 18 subjects, the histological examination revealed muscle fiber redistribution with numerical predominance of type I on the curve convexity which strongly correlated with the progression of the Cobb angle. CONCLUSION: Our findings demonstrate significant changes of muscle fiber redistribution in the paraspinal muscles of AIS with increased proportion of type I on the convexity corresponding to a significantly higher amplitude of MUPs on the same side. A possible explanation of this alteration is a secondary adaptation due to chronic high load demand.
- MeSH
- dítě MeSH
- dospělí MeSH
- elektromyografie MeSH
- hluboké zádové svaly * patologie patofyziologie MeSH
- kosterní svalová vlákna patologie fyziologie MeSH
- lidé středního věku MeSH
- lidé MeSH
- mladiství MeSH
- mladý dospělý MeSH
- progrese nemoci MeSH
- skolióza * patologie patofyziologie MeSH
- studie případů a kontrol MeSH
- Check Tag
- dítě MeSH
- dospělí MeSH
- lidé středního věku MeSH
- lidé MeSH
- mladiství MeSH
- mladý dospělý MeSH
- mužské pohlaví MeSH
- ženské pohlaví MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Východisko: Degeneratívne postihnutie šľachy patrí medzi časté dôvody vyhľadania odbornej lekárskej pomoci. Prevalencia patelárnej tendinopatie dosiahla u volejbalových hráčov 45 %, u basketbalistov 32 %. U pravidelných hráčov tenisu bola pozorovaná prevalencia radiálnej epikondylalgie až 40%. Radiálna epikondylitída bola zaznamená až u 15 % pracujúcich, ktorí vykonávali opakovaný pohyb v zápästí. Cieľ: Poukázať na etiopatogenetické súvislosti vzniku degeneratívneho procesu a zároveň predstaviť mechanizmy pôsobenia excentrického tréningu na tkanivo šľachy. Výsledky: Úspešný manažment degeneratívneho postihnutia šľachy ostáva naďalej významným terapeutickým problémom. Konzervatívne ani operačné liečebné postupy často nedosahujú presvedčivé výsledky ani pre ordinujúceho lekára, ani pre pacienta. Excentrický tréning predstavuje veľmi efektívny terapeutický postup k ovplyvneniu degeneratívneho procesu. Exaktné prevedenie a pochopenie účinkov na neurofyziologickej a molekulárnej úrovni by malo patriť do všeobecného prehľadu zdravotníckych pracovníkov, ktorí sa s touto diagnózou stretávajú.
Degenerative affections of tendons belong to frequent causes why patients find the physician help. Prevalence of patellar tendinopathy reached 45% in volleyball players and 32% in basketball players. In regular tennis players prevalence of radial epicondylalgia was observed to reach 40%. Radial epicondylitis was detected in up to 15% of workers, who performed repetitive movement in the wrist. Objective: the authors draw attention to etiopathogenic connections in the origin of degenerative process and, at the same time, present the mechanisms of the effects of eccentric training on the ligament tissue. Results: A successful management of degenerative affection of tendons remains to be an important therapeutic problem. Conservative or surgical therapeutic procedures often do not reach conclusive results for both the physician and the patient. An eccentric training represents a very efficient therapeutic procedure for influencing the degenerative process. Exactly performed application and understanding of the effects at neurophysiological and molecular level should belong to general view of medical personnel, who encounter this diagnosis.
- Klíčová slova
- excentrický pohyb, tendinóza,
- MeSH
- bolest MeSH
- kolagen metabolismus MeSH
- kosterní svalová vlákna fyziologie MeSH
- lidé MeSH
- plyometrická cvičení metody MeSH
- pracovní zátěž MeSH
- rizikové faktory MeSH
- šlachy * fyziologie metabolismus MeSH
- sportovní úrazy MeSH
- sporty MeSH
- svalová kontrakce fyziologie MeSH
- svalová síla fyziologie MeSH
- tendinopatie * etiologie metabolismus patologie rehabilitace terapie MeSH
- terapie cvičením * MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- přehledy MeSH
The impact of high-intensity exercise on disease progression and muscle contractile properties in experimental autoimmune encephalomyelitis (EAE) remains unclear. Control (CON) and EAE rats were divided into sedentary and exercise groups. Before onset (experiment 1, n=40) and after hindquarter paralysis (experiment 2, n=40), isokinetic foot extensor strength, cross sectional area (CSA) of tibialis anterior (TA), extensor digitorum longus (EDL) and soleus (SOL) and brain-derived neurotrophic factor (BDNF) levels were assessed. EAE reduced muscle fiber CSA of TA, EDL and SOL. In general, exercise was not able to affect CSA, whereas it delayed hindquarter paralysis peak. CON muscle work peaked and declined, while it remained stable in EAE. BDNF-responses were not affected by EAE or exercise. In conclusion, EAE affected CSA-properties of TA, EDL and SOL, which could, partly, explain the absence of peak work during isokinetic muscle performance in EAE-animals. However, exercise was not able to prevent muscle fiber atrophy.
- MeSH
- encefalomyelitida autoimunitní experimentální krev patologie patofyziologie MeSH
- kondiční příprava zvířat fyziologie MeSH
- kosterní svalová vlákna patologie fyziologie MeSH
- mozkový neurotrofický faktor krev MeSH
- náhodné rozdělení MeSH
- potkani inbrední LEW MeSH
- přijímání potravy MeSH
- progrese nemoci MeSH
- svalová síla MeSH
- tělesná hmotnost MeSH
- zvířata MeSH
- Check Tag
- ženské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
Commentary to: Stac adaptor proteins regulate trafficking and function of muscle and neuronal L-type Ca²⁺ channels. (Proc. Natl. Acad. Sci. 2015, pp. 602-606).
