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Start Over Subject fyziologie Date Unknown

282. Non-quantal acetylcholine release at the neuromuscular junction

Creator:
František Vyskočil, Malomouzh, A. I., and Nikolsky, E. E.
Type:
article, články, model:article, and TEXT
Subject:
Fyziologie člověka a srovnávací fyziologie, fyziologie, acetylcholin, synapse, oxid dusnatý, hibernace, physiology, acetylcholine, synapses, nitric oxide, hibernation, non-quantal release, neuromuscular junction, desensitization, resting membrane potential, choline transporter, vesicular ACh transporter, anticholinesterase, N-acetylaspartylglutamate, miniature endplate potential, 14, and 612
Language:
English
Description:
There are two principal mechanisms of acetylcholine (ACh) release from the resting motor nerve terminal: quantal and non-quantal (NQR); the former being only a small fraction of the total, at least at rest. In the present article we summarize basic research about the NQR that is undoubtedly an important trophic factor during endplate development and in adult neuromuscular contacts. NQR helps to eliminate the polyneural innervation of developing muscle fibers, ensures higher excitability of the adult subsynaptic membrane by surplus polarization and protects the RMP from depolarization by regulating the NO cascade and chloride transport. It shortens the endplate potentials by promoting postsynaptic receptor desensitization when AChE is inhibited during anti-AChE poisoning. In adult synapses, it can also activate the electrogenic Na+/K+-pump, change the degree of synchronization of quanta released by the nerve stimulation and affects the contractility of skeletal muscles., F. Vyskočil, A. I. Malomouzh, E. E. Nikolsky., and Obsahuje seznam literatury
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

283. Noninvasive assessment of local myocardium repolarization changes using high resolution surface ECG mapping

Creator:
Tyšler, M., Peter Kneppo, Turzová, M., Švehlíková, J., Slavomír Karas, Eva Nagyová, Karel Hána, and Slavomíra Filipová
Format:
print, bez média, and svazek
Type:
article, články, model:article, and TEXT
Subject:
Fyziologie člověka a srovnávací fyziologie, fyziologie, physiology, myocardium repolarization, equivalent dipole model, body surface potential mapping, active ECG electrodes, 14, and 612
Language:
English
Description:
A method using body surface potential maps for assessment of myocardium lesions with changed repolarization is presented and suitable mapping system is introduced. Differences between normal and altered QRST integral maps together with torso volume conductor model were used to determine the equivalent dipole representing the lesion. Performance of the method was studied on simulated data. Changed repolarization was modeled by shortening of myocyte action potentials in regions typical for stenosis of the main coronary arteries. The equivalent dipole estimated the positions of small lesions with a mean error of 9±4 mm (17±14 mm for larger transmural lesions). The subepicardial or subendocardial character of the lesions was reflected in the dipole orientation. Tests of the method on patients after myocardial infarction that underwent coronary intervention on a single coronary vessel showed that in 7 of 8 successfully treated patients the dipole position matched well with the treated vessel. A small dipole moment in another patient indicated unsuccessful treatment. The method was implemented in a new 128-channel mapping system. Its active electrodes, battery powered measuring unit and optical computer interface help to minimize noise in ECG and guarantee patient´s safety. The results suggest that the method and mapping system offer useful tools for noninvasive identification of local repolarization changes in the myocardium., M. Tyšler, P. Kneppo, M. Turzová, J. Švehlíková, S. Karas, E. Hebláková, K. Hána, S. Filipová., and Obsahuje bibliografii
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

284. Normocapnic high frequency oscillatory hyperventilation increases oxygenation in pigs

Creator:
Karel Roubík, Jan Pachl, and Vladimír Zábrodský
Format:
print
Type:
article, články, model:article, and TEXT
Subject:
Fyziologie člověka a srovnávací fyziologie, fyziologie, physiology, hyperventilation, normocapnia, oxygenation, high frequency ventilation, 14, and 612
Language:
English
Description:
High frequency oscillatory ventilation (HFOV), contrary to conventional ventilation, enables a safe increase in tidal volume (VT) without endangering alveoli by volutrauma or barotrauma. The aim of the study is to introduce the concept of normocapnic high frequency oscillatory hyperventilation and to assess its effect upon oxygen gain under experiment al conditions. Laboratory pigs (n=9) were investigated under total intravenous anesthesia in three phases. Phase 1: Initial volume controlled HFOV period. Phase 2 : Hyperventilation - VT was increased by (46 ± 12) % when compared to normocapnic VT during phase 1. All other ventilatory parameters were unchanged. A significant increase in PaO 2 (by 3.75 ± 0.52 kPa, p<0.001) and decrease in PaCO 2 (by -2.05 ± 0.31 kPa, p<0.001) were obtained. Phase 3: Normocapnia during hyperventilation was achiev ed by an iterative increase in the CO 2 fraction in the inspiratory gas by a CO2 admixture. All ventilatory parameters were unchanged. A significant increase in PaO2 (by 3.79 ± 0.73 kPa, p<0.001), similar to that which was observed in phase 2, was preserved in phase 3 whereas normocapnia was fully re-established. The concept of high frequency normocapnic hyperventilation offers a lung protective strategy that significantly improves oxygenation whilst preserving normocapnia., K. Roubík, J. Pachl, V. Zábrodský., and Obsahuje bibliografii a bibliografické odkazy
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

285. Notch signaling may negatively regulate neonatal rat cardiac fibroblast-myofibroblast transformation

Creator:
Fan, Y.-H., Dong, H., Pan, Q., Cao, Y.-J., Li, H., and Wang, H.-C.
Format:
print
Type:
article, články, model:article, and TEXT
Subject:
Fyziologie člověka a srovnávací fyziologie, fyziologie, physiology, cardiac fibroblast, myofibroblast, transformation, notch signaling, notch receptor, 14, and 612
Language:
English
Description:
Cardiac fibroblast-myofibroblast transformation (CMT) is a critical event in the initiation of myocardial fibrosis. Notch signaling has been shown to regulate myofibroblast transformation from other kinds of cells. However, whether Notch signaling is also involved in CMT remains unclear. In the present study, expressions of Notch receptors in cardiac fibroblasts (CFs) were examined, effects of Notch signaling inhibi tor N-[N-(3,5-difluorophenacetyl)- l-alanyl]-S-phenylglycine t-butyl ester (DAPT) and transforming growth factor-β1 (TGF-β1) on CMT were determined by increasing alpha-smooth muscle actin (α-SMA) expression and collagen synthesis, and Notch signaling was examined by analyzing expressions of Notch receptors. The results showed that: (1) Notch receptor 1, 2, 3 and 4 were all expressed in CFs; (2) DAPT promoted CMT in a time -dependent manner; (3) During the period of CMT induced by TGF-β1, expressions of Notch receptor 1, 3 and 4 in CFs were down-regulated, whereas there was no change for Notch receptor 2. Moreover, the downtrends of Notch 1, 3 and 4 were corresponding to the trend growth of α-SMA expression and collagen synthesis. These results suggested that inhibiting of Notch signaling might promote CMT. The down-regulations of Notch receptor 1, 3 and 4 induced by TGF-β1 may facilitate CMT. In conclusion, inhibition of Notch signaling might be a novel mech anism of CMT in myocardial fibrosis., Y.-H. Fan ... [et al.]., and Obsahuje bibliografii a bibliografické odkazy
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

287. Od mozku přes srdce až po tkáňové náhrady: 60 let Fyziologického ústavu AV ČR

Creator:
Petr Zouhar and Olga Kinclová-Zimmermannová
Type:
article, články, model:article, and TEXT
Subject:
Věda. Všeobecnosti. Základy vědy a kultury. Vědecká práce, Fyziologický ústav (Akademie věd ČR), věda, fyziologie, patologická fyziologie, science, 12, and 00
Language:
Czech
Description:
Fyziologický ústav AV ČR (FGÚ), význačná česká výzkumná instituce v oblasti fyziologie a patofyziologie živočichů a člověka, si v roce 2014 připomíná 60. výročí svého založení. Motto oslav „Od mozku přes srdce až po tkáňové náhrady“ vyjadřuje historický vývoj hlavních směrů výzkumu v ústavu. Již po 60 let zdejší vědci svými objevy prohlubují teoretické základy medicíny a objasňují podstatu mnoha závažných onemocnění člověka. Mezi nejvýznamnější akce k jubileu FGÚ patří nový cyklus přednášek pojmenovaný na počest slavného neurofyziologa dr. Jana Bureše. Odborné veřejnosti se tak představují významné osobnosti světové fyziologie, z nichž mnohé v minulosti s ústavem spolupracovaly nebo stále spolupracují. and Petr Zouhar, Olga Zimmermannová.
Rights:
http://creativecommons.org/publicdomain/mark/1.0/ and policy:public

289. Olfactory sensitivity in mammalian species

Creator:
Wackermannová, M., Pinc, L., and Lukáš Jebavý
Format:
print, bez média, and svazek
Type:
article, články, model:article, and TEXT
Subject:
Fyziologie člověka a srovnávací fyziologie, fyziologie, savci, physiology, mammals, olfaction, sensitivity, odor detection threshold, 14, and 612
Language:
English
Description:
Olfaction enables most mammalian species to detect and discriminate vast numbers of chemical structures called odorants and pheromones. The perception of such chemical compounds is mediated via two major olfactory systems, the main olfactory system and the vomeronasal system, as well as minor systems, such as the septal organ and the Grueneberg ganglion. Distinct differences exist not only among species but also among individuals in terms of their olfactory sensitivity; however, little is known about the mechanisms that determine these differences. In research on the olfactory sensitivity of mammals, scientists thus depend in most cases on behavioral testing. In this article, we reviewed scientific studies performed on various mammalian species using different methodologies and target chemical substances. Human and non-human primates as well as rodents and dogs are the most frequently studied species. Olfactory threshold studies on other species do not exist with the exception of domestic pigs. Olfactory testing performed on seals, elephants, and bats focused more on discriminative abilities than on sensitivity. An overview of olfactory sensitivity studies as well as olfactory detection ability in most studied mammalian species is presented here, focusing on comparable olfactory detection thresholds. The basics of olfactory perception and olfactory sensitivity factors are also described., M. Wackermannová, L. Pinc, L. Jebavý., and Obsahuje bibliografii
Rights:
http://creativecommons.org/publicdomain/mark/1.0/ and policy:public

290. One-year results from cryopreserved mitral allograft transplantation into the tricuspid position in a sheep experimental model

Creator:
Aleš Mokráček, Canadyova, J., Simunkova, Z., Fiala, R., Hmirak, M., Sulda, M., Jan Burkert, Tintera, J., Petr Kobylka, and Jaroslav Špatenka
Format:
print, bez média, and svazek
Type:
article, články, model:article, and TEXT
Subject:
Fyziologie člověka a srovnávací fyziologie, fyziologie, physiology, mitral allograft, tricuspid valve replacement, cryopreservation, sheep experimental model, 14, and 612
Language:
English
Description:
Mitral allografts are still used only exceptionally in the mitral or tricuspid position. The main indication remains infectious endocarditis of atrioventricular valves for its flexibility and low risk of infection. The aim of our study was to evaluate 1-year results of mitral allografts transplantation into the tricuspid position in a sheep model. Mitral allografts were processed, cryopreserved, a nd transplanted into the tricuspid position anatomically (Group I - 11 animals) or antianatomically (Group II - 8 animals). All survivors (4 from Group I, and 3 from Group II) were checked at 3, 6, and 12 months by echocardiography with the exception of one survivor from Group II (which was examinated only visually). Examination throughout follow-up included for mitral allograft regurgitation and annuli dilatation. At postmortem, the papillary muscles were healed and firmly anchored to the right ventricular wall in all subjects. Transventricular fixation of the papillary muscles with buttressed sutures was proven to be a stable, reproducible, and safe method for anchoring mitral allograft leaflets. There were no significant differences between the two implan tation methods. Annulus support of mitral allografts might be very useful in this type of operation and could prevent annular dilatation., A. Mokracek, J. Canadyova, Z. Simunkova, R. Fiala, M. Hmirak, M. Sulda, J. Burkert, J. Tintera, P. Kobylka, J. Spatenka., and Obsahuje bibliografii
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

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