We studied the temporal relationships and the patterns of electromyographic activities of the posterior cricoarytenoid and thyreoarytenoid muscles (laryngeal abductor and adductor), the diaphragm and abdominal muscles in anesthetized cats during mechanically induced tracheobronchial and laryngopharyngeal coughs, expiration and aspiration reflexes. The posterior cricoarytenoid muscle activity reached the maxima just before the peak of diaphragmatic activity in both types of cough and aspiration reflexes and slightly before the top of abdominal muscle activity in coughs and the expiration reflex. Thus, this muscle contributes to the inspiratory phase of coughs and aspiration reflex and also to the expulsive phase of coughs and the expiration reflex. The thyreoarytenoid muscle presented strong discharges in the compressive phase of coughs and expiration reflex (during the rising part of the abdominal muscle activity) and in the subsequent laryngoconstriction (following the diaphragmal and/or abdominal muscle activity) in all four reflexes. This muscle was also slightly activated at the beginning of the aspiration reflex. The existence of four phases of the cough reflex is also discussed., I. Poliaček, A. Stránsky, J. Jakuš, H. Baráni, Z. Tomori, E. Halašová., and Obsahuje bibliografii
The biosynthesis and metabolism of testosterone and cortisol are altered by the high levels of adipose tissue and the constant state of low-grade inflammation of obesity. Resistance exercise (REx) has become one of the main lifestyle interventions prescribed to obese individuals due to its ability to positively influence body composition and some biomarkers, such as cholesterol and insulin resistance. Yet, little research has been done in obese examining the effects of REx on the testosterone and blood cortisol responses, two integral hormones in both exercise and obesity. The obese testosterone response to REx and whether or not it is blunted compared to lean individuals remains elusive. Conflicting findings concerning the blood cortisol response have also been reported, likely due to variance in REx protocol and the level of obesity in the participants in studies. Comparatively, both of these hormones have been extremely well studied in untrained lean males, which could be used as a basis for future research in obese males. However, without this endocrinological information, it is unknown if the current acute REx prescriptions are appropriate for eliciting a favorable acute endocrinological response, and ultimately, a positive chronic adaptation in obese males., C. B. O'Leary, A: C. Hackney., and Obsahuje bibliografii
Principal vasoactive systems - renin-angiotensin system (RAS), sympathetic nervous system (SNS), nitric oxide (NO) and prostanoids - exert their vascular effects through the changes in calcium levels and/or calcium sensitization. To estimate a possible modulation of calcium sensitization by the above vasoactive systems, we studied the influence of acute and chronic blockade of particular vasoactive systems on blood pressure (BP) changes elicited in conscious normotensive rats by acute dose-dependent administration of Rho-kinase inhibitor fasudil. Adult male chronically cannulated Wistar rats were used throughout this study. The acute inhibition of NO synthase (NOS) by L-NAME enhanced BP response to fasudil, the effect being considerably augmented in rats deprived of endogenous SNS. The acute inhibition of prostanoid synthesis by indomethacin modified BP response to fasudil less than the acute NOS inhibition. The chronic NOS inhibition caused moderate BP elevation and a more pronounced augmentation of fasudilinduced BP changes compared to the effect of acute NOS inhibition. This indicates both short-term and long-term NOdependent attenuation of calcium sensitization. Long-term inhibition of RAS by captopril caused a significant attenuation of BP changes elicited by fasudil. In contrast, a long-term attenuation of SNS by chronic guanethidine treatment (in youth or adulthood) had no effect on BP response to fasudil, suggesting the absence of SNS does not affect calcium sensitization in vascular smooth muscle of normotensive rats. In conclusion, renin-angiotensin system contributes to the long-term increase of calcium sensitization and its effect is counterbalanced by nitric oxide which decreases calcium sensitization in Wistar rats., A. Brunová, M. Bencze, M. Behuliak, J. Zicha., and Obsahuje bibliografii
The effect of the chronic and acute antioxidant tempol (superoxide dismutase mimetic) treatment on cardiac ischemic tolerance was investigated in adult male Wistar rats. The first experimental group was given tempol (1 mM) in drinking water for three weeks, the second group received tempol (100 mg/kg, i.v.) 10 min before test ischemia, and control rats received the same volume of solvent. Anesthetized open-chest animals (pentobarbitone 60 mg/kg, i.p.) were subjected to 20-min coronary artery occlusion and 3-h reperfusion for infarct size determination. Ventricular arrhythmias were monitored during ischemia and at the beginning (5 min) of reperfusion. Acute tempol administration shifted the time profile of ischemic arrhythmias to the later phase and significantly increased the number of ischemic and reperfusion premature ventricular complexes, respectively (504±127 and 84±21) as compared with the chronically treated group (218±36 and 47±7) or controls (197±26 and 31±7). Acute tempol-treated rats exhibited a tendency to decrease infarct size (P = 0.087). The mechanism of proarrhythmic tempol action during ischemia and reperfusion remains to be elucidated., J. Neckář, B. Ošťádal, F. Kolář., and Obsahuje bibliografii a bibliografické odkazy
Acute liver failure (ALF) is a clinical condition with very high mortality rate. Its pathophysiological background is still poorly understood, which necessitates a search for optimal experimental ALF models with features resembling those of the human disorder. Taking into consideration reproducibility of induction of ALF, adequate animal size, cost of animals, the required time gap between insult and death of animals (“therapeutic window”), potential risk to investigator and other aspects, administration of thioacetamide (TAA) in rats is currently most recommended. However, the fundamental details of this ALF model have not yet been evaluated. This prompted us to investigate, first, the course of ALF as induced by intraperitoneal TAA at doses increasing from 175 to 700 mg/kg BW per day. The animals’ survival rate, plasma alanine and aspartate aminotransferase activities, and bilirubin and ammonia levels were determined over the follow-up period. Second, we examined whether Wistar and Lewis rats exhibit any differences in the course of ALF induced by different TAA doses. We found that the optimal dose for ALF induction in rats is 350 mg.kg-1 i.p., given as a single injection. Wistar rats proved more susceptible to the development of TAA-induced ALF compared with Lewis rats. Collectively, our present findings provide a sound methodological background for experimental studies aimed at evaluation of pathophysiology and development of new approaches in the therapy of ALF., E. Koblihová, I. Mrázová, Z. Vernerová, M. Ryska., and Obsahuje bibliografii
V článku s uvedeným názvem, publikovaným ve 3. čísle Čs. čas. fyz. 68, 144 (2018) mne upoutaly (a přiměly k napsání této poznámky) dvě věty: "...Deset principů Leidenského manifestu nastavuje dosavadní praxi hodnocení vědy v Česku nemilosrdně kritické zrcadlo, ale nedělejme si iluze, že tento dokument pohne českým vědeckým vesmírem..." a "...pokušení nechat rozhodovat čísla v Česku podivuhodně odolala Akademie věd."..., Jiří Kamarád., and Obsahuje bibliografické odkazy