Expression of the muscle phenotype is the result of interaction between intrinsic and extrinsic factors, the latter including innervation, mechanical influences and hormonal signals. This minireview summarizes some of the current knowledge regarding the regulation of myosin heavy chain (MHC) isoform transitions during muscle development and regeneration. It describes the role of genetic factors, neural and mechanical influences and it focuses on the contribution of thyroid hormones to the differentiation of muscle fiber phenotypes as shown by the regulation of the expression of MHC isoforms and development of myofibrillar ATPase activity. Finally, it shortly summarizes results regarding the differentiation of MHC isoforms in regenerated muscle fibers of the graft after heterochronous isotransplantation in rats with different thyroid status., T. Soukup, I. Jirmanová., and Obsahuje bibliografii
We tested the effects of epidermal growth factor (EGF) on Na+/H+ exchanger (NHE) activity using urogastrone for treatment of Wistar rats and rat kidney tissue slices. NHE activity was monitored in isolated kidney brush border membrane vesicles by following fluorescence quenching of acridine orange. A significant increase of NHE activity was detected as early as 5 min after addition of urogastrone to rat kidney slices in vitro. In Wistar rats treated with urogastrone we also found increased NHE activity (by about 12 %). Both changes of NHE activity were the result of a significant rise of Vmax value and an apparent decrease in Km value in in vitro experiments. The rise of NHE activity caused by urogastrone was sensitive to the inhibitors of transcription and translation. The presence of phosphatase inhibitor, NaF, elevated NHE activity of non-stimulated as well as of urogastrone-stimulated exchanger, suggesting that phosphorylation plays an important role in Na+/H+ exchange. Osmolarity of the medium seems to regulate NHE activity in such a manner that both hyper- and hypoosmolar conditions inhibited NHE activity. The absence of Ca2+ions produced a 60 % decrease of NHE activity. The chemical modification of histidine residues with diethyl pyrocarbonate or SH groups with N-ethylmaleimide inhibited NHE activity., K. Barišić, O. Karužić, J. Petrik, T. Ž. Grubišić., and Obsahuje bibliografii
Sox3/SOX3 gene is considered to be one of the earliest neural markers in vertebrates. Despite the mounting evidence that Sox3/SOX3 is one of the key players in the development of the nervous system, limited data are available regarding the transcriptional regulation of its expression. This review is focused on the retinoic acid induced regulation of SOX3 gene expression, with particular emphasis on the involvement of retinoid receptors. Experiments with human embryonal carcinoma cells identified two response elements in volved in retinoic acid/retinoid X receptor-dependent activation of the SOX3 gene expression: distal atypical retinoic acid-response element, consisting of two unique G-rich boxes separated by 49 bp, and proximal element comprising DR-3-like motif, composed of two imperfect hexameric half-sites. Importantl y, the retinoic acid-induced SOX3 gene expression could be significantly down-regulated by a synthetic antagonist of retinoid receptors. This cell model provides a solid base for further studies on mechanism(s) underlying regulation of expression of SOX3 gene, which could improve the understanding of molecular signals that induce neurogenesis in the stem/progenitor cells both during development and in adulthood., G. Nikčević ... [et al.]., and Obsahuje bibliografii a bibliografické odkazy
Metabolic consequences of direct muscle trauma are insufficiently defined. Their effects on the ubiquitin-proteasome pathway (UPP) of protein degradation in human skeletal muscles are as yet unknown. Thus, we investigated whether the UPP is involved in the metabolic response evoked in directly traumatized human skeletal muscles. Biopsies were obtained from contused muscles after fractures and from normal muscles during elective implant removal (control). As estimated by western blot analyses, concentrations of free ubiquitin and ubiquitin protein conjugates were similar in extracts from injured and uninjured muscles. Ubiquitin protein ligation rates were reduced after injury (1.5±0.2 vs. 1.0±0.15 fkat/μg; p=0.04). Chymotryptic-, tryptic- and caspase-like proteasome peptidase activities (total activity minus activity in the presence of proteasome inhibitors) increased significantly after trauma (p=0.04 - 0.001). Significant increases in total chymotryptic- and caspase-like activities were attributable to proteasome activation. Our results extend the possible role of the UPP in muscle wasting to direct muscle trauma. They further suggest that the effects of direct mechanical trauma are not limited to the proteasome and imply that ubiquitin protein ligase systems are also involved. Based on the potential role of the UPP in systemic diseases, it might also be a therapeutic target to influence muscle loss in critically ill blunt trauma patients, in which large proportions of muscle are exposed to direct trauma. and Obsahuje bibliografii a bibliografické odkazy
The colorectum (late distal colon) is innervated by the sympathetic nervous system, and many colorectal diseases are related to disorders of the sympathetic nervous system. The sympathetic regulation of colorectal ion transport is rarely reported. The present study aims to investigate the effect of norepinephrine (NE) in the normal and catecholamine-depleted condition to clarify the regulation of the sympathetic adrenergic system in ion transport in the rat colorectum. NE-induced ion transport in the rats colorectum was measured by short-circuit current (Isc) recording; the expression of β-adrenoceptors and NE transporter (NET) were quantified by real-time PCR, and western blotting. When the endogenous catecholamine was depleted by reserpine, the baseline Isc in the colorectum was increased significantly comparing to controls. NE evoked downward ∆Isc in colorectum of treated rats was 1.8-fold of controls. The expression of β 2 -adrenoceptor protein in the colorectal mucosa was greater than the control, though the mRNA level was reduced. Ho wever, NET expression was significantly lower in catecholamine-depleted rats compared to the controls. In conclusion, the sympathetic nervous system plays an important role in regulating basal ion transport in the colorectum. Disorders of sympathe tic neurotransmitters result in abnormal ion transport, β-adrenoceptor and NET are involved in the process., X. Zhang, Y. Li, X. Zhang, Z. Duan, J. Zhu., and Obsahuje bibliografii
MicroRNAs (miRNAs) are a class of short non-coding regulatory RNA molecules which play an important role in intracellular communication and cell signaling and which influence cellular processes such as proliferation, differentiation, and cellular death. Over the past two decades, the crucial role of m icroRNAs in controlling tissue homeostasis and disease in cardiovascular systems has become widely recogni zed. By controlling the expression levels of their targets, several miRNAs have been shown to modulate the function of endothelial cells (miR-221/222 and -126), vascular smooth muscle cells (miR-143/145) and macrophages (miR-33, -758, and -26), thereby regulating the development and progression of atherosclerosis. The stability of miRNAs within the blood suggests that circulating miRNAs may function as important biomarkers of disease development and progression. Numerous circulating miRNAs have been found to be dysregulated in a wide variety of different disease states, including diabetes, cancer, and cardiovascular disease., D. Dlouhá, J. A. Hubáček., and Obsahuje bibliografii
The present study was focused on regulatory role of nitric oxide on functional properties of the cardiac Na, K-ATPase in three various animal models of hypertension: spontaneously hypertensive male rats (SHR) with increased activity of nitric oxide synthase (NOS) by 60 % (Sh1), SHR with decreased activity of NOS by 40 % (Sh2) and rats with hypertension induced by L-NAME (40 mg/kg/day) with depressed activity of NOS by 72 % (LN). Studying the utilization of energy substrate we observed higher Na, K-ATPase activity in the whole concentration range of ATP in Sh1 and decreased activity in Sh2 and LN. Evaluation of kinetic parameters revealed an increase of Vmax value by 37 % in Sh1 and decrease by 30 % in Sh2 and 17 % in LN. The KM value remained unchanged in Sh2 and LN, but was lower by 38 % in Sh1 indicating increased affinity of the ATP binding site, as compared to controls. During the activation with Na+ we observed increased Vmax by 64 % and increased KNa by 106 % in Sh1. In Sh2 we found decreased Vmax by 40 % and increased KNa by 38 %. In LN, the enzyme showed unchanged Vmax with increased KNa by 50 %. The above data indicate a positive role of increased activity of NOS in improved utilization of ATP as well as enhanced binding of Na+ by the cardiac Na, K-ATPase., J. Vlkovičová, V. Javorková, L. Mézešová, O. Pecháňová, N. Vrbjar., and Obsahuje bibliografii a bibliografické odkazy
Postižení kognitivních funkcí (KF) je ve všech fázích roztroušené sklerózy (RS) důležitým prediktorem kvality života a je nejčastější příčinou ztráty zaměstnání. Deficit mívá nejběžněji charakter mírné kognitivní poruchy a jeho projevy jsou velmi variabilní, a proto je důležitá přesná neuropsychologická diagnostika. Mírný kognitivní deficit u RS zahrnuje obvykle zpomalení rychlosti zpracování informací, poruchu komplexní pozornosti, paměti a exekutivních funkcí. Minimalizaci dopadů onemocnění může významně ovlivnit rehabilitace kognitivních funkcí. Rehabilitace kognitivních poruch přešla od metody tužka-papír k rehabilitaci pomocí počítačových programů. Uvádíme řadu studií zabývajících se rehabilitací kognitivních funkcí včetně kvantitativních i kvalitativních výsledků jednotlivých studií a sledujeme výsledky rehabilitace v krátkodobém i dlouhodobějším horizontu. Pozitivní efekt rehabilitace se jednoznačně ukazuje v oblasti zvyšování kvality života a snižování deprese. Předmětem diskuze však zůstává, zda se nejedná jen o efekt krátkodobý, a také to, jaké další faktory mohou pozitivní efekt tréninku podpořit., In all phases of multiple sclerosis (MS), cognitive deficits (CD) are an important predictor of the quality of life and the frequent cause of job loss. The deficits usually have a character of a mild cognitive impairment and their manifestation varies greatly. Therefore, accurate neuropsychological assessment is important. Mild cognitive symptoms in MS usually include problems with the speed of information processing and visual learning, dysfunction of complex attention and executive functions. Rehabilitation of cognitive functions can significantly influence and minimize the impact of the disease. Rehabilitation of cognitive deficits has changed from “pencil-paper” method to computer-program-based rehabilitation. This papers reviews a range of studies dealing with cognitive function rehabilitation, including both quantitative and qualitative results, and both short- and long-term results. The positive effects of rehabilitation are clearly shown by increased quality of life and alleviated depressive symptoms. Further discussion is needed about durability of this effect and what other factors can positively support the training effects. Key words: multiple sclerosis – computerized cognitive training – magnetic resonance – cognitive rehabilitation – cognitive dysfunction – neuropsychological assessment The authors declare they have no potential conflicts of interest concerning drugs, products, or services used in the study. The Editorial Board declares that the manuscript met the ICMJE “uniform requirements” for biomedical papers., and D. Chmelařová, Z. Ambler, M. Dostál, V. Vobořilová
The aim of the present study was to quantify the effect of multisensory rehabilitation on rats’ cognition after an experimental brain trauma and to assess its possible clinical implications. The complex intermittent multisensory rehabilitation consisted of currently used major therapeutic procedures targeted at the improvement of cognitive functions; including multisensory and motor stimulation and enriched environment. We have confirmed this positive effect of early multisensory rehabilitation on the recovery of motor functions after traumatic brain injury. However, we have been able to prove a positive effect on the recovery of cognitive functions only with respect to the frequency of efficient search st rategies in a Barnes maze test, while results for search time and travelled distance were not significantly different between st udy groups. We have concluded that the positive effects of an early treatment of functional deficits are comparable with the clinical results in early neurorehabilitation in human patients after brain trauma. It might therefore be reasonable to apply these experimental results to human medical neurorehabilitation care., M. Lippert-Grüner ... [et al.]., and Obsahuje bibliografii a bibliografické odkazy