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182. 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
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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

184. Olfactory sensitivity in mammalian species

Creator:
Wackermannová, M., Pinc, L., and Lukáš Jebavý
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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

185. 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
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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

186. Oral administration of polyphenolic compounds from Cognac decreases ADP-induced platelet aggregation and reduces chronotropic effect of isoprenaline in rats

Creator:
Carusio, N., Wangensteen, R., Filippelli, A., and Ramaroson Andriantsitohaina
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Subject:
Experimentální medicína, fyziologie, polyfenoly, trombocyty, oxid dusnatý, physiology, polyphenols, thrombocytes, nitric oxide, Cognac, platelet aggregation, isoprenaline, 14, and 616-092
Language:
English
Description:
This study sought to evaluate whether consumption of polyphenol extract from Cognac (CPC) modulates platelet activation and cardiovascular reactivity in rats. Male Wistar rats were treated daily for 4 weeks by intra-gastric gavage receiving CPC at 80 mg/kg/day or vehicle (5 % glucose). Platelet adhesion and aggregation in response to different activators were assessed. Cardiac and vascular reactivity in response to various agonists as well as NO measurement by electron paramagnetic resonance technique were investigated in isolated heart and thoracic aorta. Oral administration of CPC decreased platelet aggregation induced by ADP but not by collagen. CPC did not affect adhesion to collagen. The chronotropic but not the inotropic response to isoprenaline was reduced without alteration of NO production in hearts from CPC-treated rats. CPC treatment did not affect ex vivo relaxation to acetylcholine nor NO content of rat aorta. CPC did not significantly alter the response to phenylephrine in aorta despite the participation of endothelial vasoconstrictor products. In summary, chronic treatment with CPC has no impact on ex vivo vascular and cardiac reactivity; however, it reduced heart work and platelet aggregation. These data suggest the existence of compounds in Cognac that may decrease the risk of coronary thrombosis and protect against some cardiac diseases., N. Carusio, R. Wangensteen, A. Filippelli, R. Andriantsitohaina., and Obsahuje bibliiografii a bibliografické odkazy
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

187. Orexin affects dorsal root ganglion neurons: a mechanism for regulating the spinal nociceptive processing

Creator:
Yan, J.-A., Ge, L., Huang, W., Song, B., Chen, Xiao-wei, and Yu, Zheng-ping
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Subject:
Fyziologie člověka a srovnávací fyziologie, fyziologie, spinální ganglia, mícha, vápník, physiology, spinal ganglia, spinal cord, calcium, orexins, nociceptive transmission, dorsal root ganglion neurons, orexin-1 receptor, patch clamp, 14, and 612
Language:
English
Description:
Orexins (orexin A and B) are initially known to be a hypothalamic peptide critical for feeding and normal wakefulness. In addition, emerging evidence from behavioral tests suggests that orexins are also involved in the regulation of nociceptive processing, suggesting a novel potential therapeutic approach for pain treatment. Both spinal and supraspinal mechanisms appear to contribute to the role of orexin in nociception. In the spinal cord, dorsal root ganglion (DRG) neurons are primary afferent neurons that transmit peripheral stimuli to the pain-processing areas. Morphological results show that both orexin A and orexin-1 receptor are distributed in DRG neurons. Moreover, by using whole-cell patch-clamp recordings and calcium imaging measurements we found that orexin A induced excitability and intracellular calcium concentration elevation in the isolated rat DRG neurons, which was mainly dependent on the activation of spinal orexin-1 receptor. Based on these findings, we propose a hypothesis that the direct effect of orexin A on DRG neurons would represent a possible mechanism for the orexinergic modulation of spinal nociceptive transmission., J.-A. Yan, L. Ge, W. Huang, B. Song, X.-W. Chen, Z.-P. Yu., and Obsahuje bibliografii a bibliografické odkazy
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

188. Orthogonal polarization spectral imaging

Creator:
Vladimír Černý, Zdeněk Turek, and Renata Černá Pařízková
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Subject:
Fyziologie člověka a srovnávací fyziologie, fyziologie, polarizace (fyzika), physiology, polarization (physics), mikrocirkulace, ortogonální polarizace, spektrální zobrazení, microcirculation, orthogonal polarization, spectral imaging, 14, and 612
Language:
English
Description:
The microcirculation plays a crucial role in the interaction between blood and tissues both in physiological and pathophysiological states. Despite its critical role in numer ous diseases including diabetes, hypertension, sepsis or multiple organ failure, methods for direct visualization and quantitative assessm ent of human microcirculation at the bedside are limited. Orthogonal polarization spectral (OPS) imaging is a relatively new noninvasive method for assessment of human microcirculation without using fluorescent dyes. Recent clinical studies using OPS imaging in various pathological states have shown a wide spectrum of different clinical applications with evident impact on the diagnosis, treatment or prognosis assessment. Thus, there is a great effort to validate OPS imaging for various clinical purposes. The principles of OPS imaging, validation studies, its advantages, limitations, methods of quantitative assessment and current experience in clinical practice are discussed., V. Černý, Z. Turek, R. Pařízková., and Obsahuje bibliografii a bibliografické odkazy
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

189. Overweight and decreased baroreflex sensitivity as independent risk factors for hypertension in children, adolescents, and young adults

Creator:
Krontorádová, K., Nataša Honzíková, Bohumil Fišer, Zuzana Nováková, Eva Závodná, Hana Hrstková, and Petr Honzík
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Subject:
Fyziologie člověka a srovnávací fyziologie, fyziologie, krevní tlak, nadváha, hypertenze, adolescenti, physiology, blood pressure, overweight, hypertension, adolescents, baroreflex sensibility, 14, and 612
Language:
English
Description:
We studied the relationship between blood pressure (BP), body mass index (BMI, kg/m2) and baroreflex sensitivity (BRS, ms/mmHg) in adolescents. We examined 34 subjects aged 16.2±2.4 years who had repeatedly high causal BP (H) and 52 controls (C) aged 16.4±2.2 years. Forty-four C and 22 H were of normal weight (BMI between 19-23.9), and 8 C and 12 H were overweight (BMI between 24-30). Systolic BP was recorded beat-to-beat for 5 min (Finapres, controlled breathing 0.33 Hz). BRS was determined by the cross-spectral method. The predicting power of BMI and BRS for hypertension was evaluated by sensitivity, specificity, and receiver operating curve (ROC - plot of sensitivity versus specificity). H compared with C had lower BRS (p<0.01) and higher BMI (p<0.05). Multiple logistic regression analysis (p<0.001) revealed that a decreased BRS (p<0.05) and an increased BMI (p<0.01) were independently associated with an increased risk of hypertension. No correlation between BMI and BRS was found either in H or in C. Following optimal critical values by ROC, the sensitivity, specificity and area under ROC were determined for: BMI - 22.2 kg/m2, 61.8 %, 69.2 %, 66.0 %; BRS - 7.1 ms/mmHg, 67.7 %, 69.2 %, 70.0 %; BMI and BRS - 0.439 a.u., 73.5 %, 82.7 %, and 77.3 %. Decreased BRS and overweight were found to be independent risk factors for hypertension., K. Krontorádová, N. Honzíková, B. Fišer, Z. Nováková, E. Závodná, H. Hrstková, P. Honzík., and Obsahuje bibliografii a bibliografické odkazy
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

190. Participation of nitric oxide in different models of experimental hypertension

Creator:
Török, Jozef
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Subject:
Fyziologie člověka a srovnávací fyziologie, fyziologie, endotel, oxid dusnatý, endoteliální dysfunkce, hypertenze, physiology, endothelium, nitric oxide, endothelial dysfunction, hypertension, reactive oxygen species, arterial structural changes, NO-deficient hypertension, genetic hypertension, salt hypertension, 14, and 612
Language:
English
Description:
This review concerns the role of nitric oxide (NO) in the pathogenesis of different models of experimental hypertension (NO-deficient, genetic, salt-dependent), which are characterized by a wide range of etiology. Although the contribution of NO may vary between different models of hypertension, a unifying characteristic of these models is the presence of oxidative stress that participates in the maintenance of elevated arterial pressure and seems to be a common denominator underlying endothelial dysfunction in various forms of experimental hypertension. Besides the imbalance between the endothelial production of vasorelaxing and vasoconstricting compounds as well as the relative insufficiency of vasodilator systems to compensate augmented vasoconstrictor systems, there were found numerous structural and functional abnormalities in blood vessels and heart of hypertensive animals. The administration of antihypertensive drugs, antioxidants and NO donors is capable to attenuate blood pressure elevation and to improve morphological and functional changes of cardiovascular system in some but not all hypertensive models. The failure to correct spontaneous hypertension by NO donor administration reflects the fact that sympathetic overactivity plays a key role in this form of hypertension, while NO production in spontaneously hypertensive rats might be enhanced to compensate increased blood pressure. A special attention should be paid to the modulation of sympathetic nervous activity in central and peripheral nervous system. These results extend our knowledge on the control of the balance between NO and reactive oxygen species production and are likely to be a basis for the development of new approaches to the therapy of diseases associated with NO deficiency., J. Török., and Obsahuje bibliografii a bibliografické odkazy
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public