The normal physiologic range of QRS complex duration spans between 80 and 125 ms with known differences between females and males which cannot be explained by the anatomical variations of heart sizes. To investigate the reasons for the sex differences as well as for the wide range of normal values, a technology is proposed based on the singular value decomposition and on the separation of different orthogonal components of the QRS complex. This allows classification of the proportions of different components representing the 3-dimensional representation of the electrocardiographic signal as well as classification of components that go beyond the 3-dimensional representation and that correspond to the degree of intricate convolutions of the depolarisation sequence. The technology was applied to 382,019 individual 10-s ECG samples recorded in 639 healthy subjects (311 females and 328 males) aged 33.8 ± 9.4 years. The analyses showed that QRS duration was mainly influenced by the proportions of the first two orthogonal components of the QRS complex. The first component demonstrated statistically significantly larger proportion of the total QRS power (expressed by the absolute area of the complex in all independent ECG leads) in females than in males (64.2 ± 11.6% vs 59.7 ± 11.9%, p < 0.00001-measured at resting heart rate of 60 beats per minute) while the second component demonstrated larger proportion of the QRS power in males compared to females (33.1 ± 11.9% vs 29.6 ± 11.4%, p < 0.001). The analysis also showed that the components attributable to localised depolarisation sequence abnormalities were significantly larger in males compared to females (2.85 ± 1.08% vs 2.42 ± 0.87%, p < 0.00001). In addition to the demonstration of the technology, the study concludes that the detailed convolution of the depolarisation waveform is individual, and that smoother and less intricate depolarisation propagation is the mechanism likely responsible for shorter QRS duration in females.

• MeSH
• algoritmy MeSH
• analýza dat MeSH
• biologická variabilita populace MeSH
• dospělí MeSH
• elektrofyziologické jevy * účinky léků   MeSH
• elektrokardiografie * metody   MeSH
• lidé středního věku MeSH
• lidé MeSH
• sexuální faktory MeSH
• srdce účinky léků   fyziologie   MeSH
• výpočetní biologie metody   MeSH
• zdraví dobrovolníci pro lékařské studie MeSH
• Check Tag
• dospělí MeSH
• lidé středního věku MeSH
• lidé MeSH
• mužské pohlaví MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Acute excessive ethyl alcohol (ethanol) consumption alters cardiac electrophysiology and can evoke cardiac arrhythmias, e.g., in 'holiday heart syndrome'. Ethanol acutely modulates numerous targets in cardiomyocytes, including ion channels, Ca2+-handling proteins and gap junctions. However, the mechanisms underlying ethanol-induced arrhythmogenesis remain incompletely understood and difficult to study experimentally due to the multiple electrophysiological targets involved and their potential interactions with preexisting electrophysiological or structural substrates. Here, we employed cellular- and tissue-level in-silico analyses to characterize the acute effects of ethanol on cardiac electrophysiology and arrhythmogenesis. Acute electrophysiological effects of ethanol were incorporated into human atrial and ventricular cardiomyocyte computer models: reduced INa, ICa,L, Ito, IKr and IKur, dual effects on IK1 and IK,ACh (inhibition at low and augmentation at high concentrations), and increased INCX and SR Ca2+ leak. Multiscale simulations in the absence or presence of preexistent atrial fibrillation or heart-failure-related remodeling demonstrated that low ethanol concentrations prolonged atrial action-potential duration (APD) without effects on ventricular APD. Conversely, high ethanol concentrations abbreviated atrial APD and prolonged ventricular APD. High ethanol concentrations promoted reentry in tissue simulations, but the extent of reentry promotion was dependent on the presence of altered intercellular coupling, and the degree, type, and pattern of fibrosis. Taken together, these data provide novel mechanistic insight into the potential proarrhythmic interactions between a preexisting substrate and acute changes in cardiac electrophysiology. In particular, acute ethanol exposure has concentration-dependent electrophysiological effects that differ between atria and ventricles, and between healthy and diseased hearts. Low concentrations of ethanol can have anti-fibrillatory effects in atria, whereas high concentrations promote the inducibility and maintenance of reentrant atrial and ventricular arrhythmias, supporting a role for limiting alcohol intake as part of cardiac arrhythmia management.

• MeSH
• akční potenciály účinky léků   MeSH
• elektrofyziologické jevy účinky léků   MeSH
• ethanol škodlivé účinky   MeSH
• fibróza MeSH
• iontové kanály metabolismus   MeSH
• kardiomyocyty účinky léků   metabolismus   MeSH
• lidé MeSH
• mezerový spoj účinky léků   metabolismus   MeSH
• počítačová simulace MeSH
• remodelace cév účinky léků   MeSH
• srdce účinky léků   patofyziologie   MeSH
• srdeční arytmie patologie   patofyziologie   MeSH
• srdeční síně účinky léků   patologie   patofyziologie   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Research Support, N.I.H., Extramural MeSH

Melatonin is assumed to confer cardioprotective action via antioxidative properties. We evaluated the association between ventricular tachycardia and/or ventricular fibrillation (VT/VF) incidence, oxidative stress, and myocardial electrophysiological parameters in experimental ischemia/reperfusion under melatonin treatment. Melatonin was given to 28 rats (10 mg/kg/day, orally, for 7 days) and 13 animals received placebo. In the anesthetized animals, coronary occlusion was induced for 5 min followed by reperfusion with recording of unipolar electrograms from ventricular epicardium with a 64-lead array. Effects of melatonin on transmembrane potentials were studied in ventricular preparations of 7 rats in normal and "ischemic" conditions. Melatonin treatment was associated with lower VT/VF incidence at reperfusion, shorter baseline activation times (ATs), and activation-repolarization intervals and more complete recovery of repolarization times (RTs) at reperfusion (less baseline-reperfusion difference, ΔRT) (p < 0.05). Superoxide dismutase (SOD) activity was higher in the treated animals and associated with ΔRT (p = 0.001), whereas VT/VF incidence was associated with baseline ATs (p = 0.020). In vitro, melatonin led to a more complete restoration of action potential durations and resting membrane potentials at reoxygenation (p < 0.05). Thus, the antioxidative properties of melatonin were associated with its influence on repolarization duration, whereas the melatonin-related antiarrhythmic effect was associated with its oxidative stress-independent action on ventricular activation.

• MeSH
• antiarytmika farmakologie   MeSH
• antioxidancia farmakologie   MeSH
• elektrofyziologické jevy účinky léků   MeSH
• elektrokardiografie účinky léků   MeSH
• fibrilace komor farmakoterapie   MeSH
• krysa rodu rattus MeSH
• melatonin farmakologie   MeSH
• potkani Wistar MeSH
• reperfuzní poškození myokardu farmakoterapie   MeSH
• reperfuzní poškození farmakoterapie   MeSH
• srdeční arytmie farmakoterapie   MeSH
• srdeční elektrofyziologie metody   MeSH
• srdeční komory účinky léků   MeSH
• zvířata MeSH
• Check Tag
• krysa rodu rattus MeSH
• mužské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH

Bark beetles kill apparently vigorous conifers during epidemics by means of pheromone-mediated aggregation. During non-endemic conditions the beetles are limited to use trees with poor defense, like wind-thrown. To find olfactory cues that help beetles to distinguish between trees with strong or weak defense, we collected volatiles from the bark surface of healthy felled or standing Picea abies trees. Furthermore, living trees were treated with methyl jasmonate in order to induce defense responses. Volatiles were analyzed by combined gas chromatography and electroantennographic detection (GC-EAD) on Ips typographus antennae. Compounds eliciting antennal responses were characterized by single sensillum recording for identification of specific olfactory sensory neurons (OSN). Release of monoterpene hydrocarbons decreased, while oxygenated compounds increased, from spring to early summer in felled trees. In both beetle sexes particular strong EAD activity was elicited by trace amounts of terpene alcohols and ketones. 4-Thujanol gave a very strong response and the absolute configuration of the tested natural product was assigned to be (+)-trans-(1R,4S,5S)-thujanol by stereoselective synthesis and enantioselective gas chromatography. One type of OSN responded to all ketones and five other OSN were characterized by the type of compounds that elicited responses. Three new OSN classes were found. Of the eight EAD-active compounds found in methyl jasmonate-treated bark, the known anti-attractant 1,8-cineole was the one most strongly induced. Our data support the hypothesis that highly active oxygenated host volatiles could serve as positive or negative cues for host selection in I. typographus and in other bark beetles.

• MeSH
• acetáty farmakologie   MeSH
• brouci fyziologie   MeSH
• cyklopentany farmakologie   MeSH
• elektrofyziologické jevy účinky léků   MeSH
• kůra rostlin chemie   účinky léků   metabolismus   MeSH
• monoterpeny chemická syntéza   chemie   farmakologie   MeSH
• oxylipiny farmakologie   MeSH
• plynová chromatografie s hmotnostně spektrometrickou detekcí MeSH
• smrk chemie   metabolismus   MeSH
• stereoizomerie MeSH
• styren chemie   farmakologie   MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH

Electrophysiological studies of whole organ systems in vitro often require measurement of nerve activity and/or stimulation of the organ via the associated nerves. Currently two-compartment setups are used for such studies. These setups are complicated and require two fluids in two separate compartments and stretching the nerve across one chamber to the other, which may damage the nerves. We aimed at developing a simple single compartment setup by testing the electrophysiological properties of FC-770 (a perfluorocarbon) for in vitro recording of bladder afferent nerve activity and electrical stimulation of the bladder. Perflurocarbons are especially suitable for such a setup because of their high oxygen carrying capacity and insulating properties. In male Wistar rats, afferent nerve activity was recorded from postganglionic branches of the pelvic nerve in vitro, in situ and in vivo. The bladder was stimulated electrically via the efferent nerves. Organ viability was monitored by recording spontaneous contractions of the bladder. Additionally, histological examinations were done to test the effect of FC-770 on the bladder tissue. Afferent nerve activity was successfully recorded in a total of 11 rats. The bladders were stimulated electrically and high amplitude contractions were evoked. Histological examinations and monitoring of spontaneous contractions showed that FC-770 maintained organ viability and did not cause damage to the tissue. We have shown that FC-770 enables a simple, one compartment in vitro alternative for the generally used two compartment setups for whole organ electrophysiological studies.

• MeSH
• elektrická stimulace metody   MeSH
• elektrofyziologické jevy účinky léků   fyziologie   MeSH
• fluorokarbony farmakologie   MeSH
• krysa rodu rattus MeSH
• močový měchýř účinky léků   inervace   fyziologie   MeSH
• neurony aferentní účinky léků   fyziologie   MeSH
• potkani Wistar MeSH
• zvířata MeSH
• Check Tag
• krysa rodu rattus MeSH
• mužské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH

Ancistrotermes dimorphus is a common Macrotermitinae representative, facultative inquiline by its life-style, occurring in South-East China. Sex pheromone is used for couple formation and maintenance, and it is produced by and released from the female sternal gland and is highly attractive to males. Based on our combined behavioral, chemical and electrophysiological analyses, we identified (3Z,6Z)-dodeca-3,6-dien-1-ol as the female sex pheromone of A. dimorphus as it evoked the tandem behavior at short distance, and the active quantities ranged from 0.01ng to 10ng. Interestingly, GC-MS analyses of SPME extracts showed another compound specific to the female sternal gland, (3Z)-dodec-3-en-1-ol, which showed a clear GC-EAD response. However, this compound has no behavioral function in natural concentrations (0.1ng), while higher amounts (1ng) inhibit the attraction achieved by (3Z,6Z)-dodeca-3,6-dien-1-ol. The function of (3Z)-dodec-3-en-1-ol is not fully understood, but might be linked to recognition from sympatric species using the same major compound, enhancing the long-distance attraction, or informing about presence of other colonies using the compound as a trail-following pheromone. The sternal gland secretion of Ancistrotermes females contains additional candidate compounds, namely (3E,6Z)-dodeca-3,6-dien-1-ol and (6Z)-dodec-6-en-1-ol, which are not perceived by males' antennae in biologically relevant amounts.

• MeSH
• elektrofyziologické jevy účinky léků   MeSH
• Isoptera chemie   fyziologie   MeSH
• sexuální chování zvířat účinky léků   MeSH
• sexuální lákadla chemie   izolace a purifikace   farmakologie   MeSH
• tykadla členovců fyziologie   MeSH
• zvířata MeSH
• Check Tag
• mužské pohlaví MeSH
• ženské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Geografické názvy
• Čína MeSH

In this study, evidence is provided on the formation of electronically excited species in human multiple myeloma cells U266 in the growth medium exposed to hydrogen peroxide (H2O2). Two-dimensional imaging of ultra-weak photon emission using highly sensitive charge coupled device camera revealed that the addition of H2O2 to cell suspension caused the formation of triplet excited carbonyls (3)(R = O)*. The kinetics of (3)(R = O)* formation in the real time, as measured by one-dimensional ultra-weak photon emission using low-noise photomultiplier, showed immediate enhancement followed by a slow decay. In parallel to the formation of (3)(R = O)*, the formation of singlet oxygen ((1)O2) in U266 cells caused by the addition of H2O2 was visualized by the imaging of (1)O2 using the green fluorescence of singlet oxygen sensor green detected by confocal laser scanning microscopy. Additionally, the formation of (1)O2 after the addition of H2O2 to cell suspension was detected by electron paramagnetic resonance spin-trapping spectroscopy using 2,2,6,6-tetramethyl-4-piperidone. Presented results indicate that the addition of H2O2 to cell suspension results in the formation of (3)(R = O)* and (1)O2 in U266 cell suspension. The contribution of the cell-free medium to the formation of electronically excited species was discussed.

• MeSH
• elektrofyziologické jevy * účinky léků   MeSH
• elektronová paramagnetická rezonance MeSH
• konfokální mikroskopie MeSH
• lidé MeSH
• mnohočetný myelom metabolismus   MeSH
• nádorové buněčné linie MeSH
• nádorové buňky kultivované MeSH
• peroxid vodíku metabolismus   farmakologie   MeSH
• reaktivní formy kyslíku metabolismus   MeSH
• viabilita buněk účinky léků   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

OBJECTIVES: Electrogastrography (EGG) is a non-invasive investigation of gastric myoelectrical activity. The aim of study was to evaluate the impact of erythromycin on EGG in gastrointestinal toxic injury induced by dextran sodium sulphate (DSS) in experimental pigs. METHODS: The experiments were carried out on 12 adult pigs (weighing 30-35 kg). EGG was recorded using Digitrapper equipment (Synectics Medical AB, Stockholm). Running spectrum activity was used for EGG evaluation. There were two groups of animals: Group I: 6 controls with erythromycin administration (1,600 mg intragastrically); Group II: 6 animals treated with DSS (for 5 days, 0.25 g/kg per day in a dietary bolus) followed by erythromycin administration. Baseline and subsequent six separate 30-minute EGG-recordings (from time 0 to 360 min) were accomplished in each animal. RESULTS AND CONCLUSION: A total of 84 records were analysed. Baseline dominant frequency of slow waves was fully comparable in both groups. In Group I, there was a significant increase in dominant frequency after erythromycin administration (maximum between 240-360 min). There was a flat non-significant and delayed increase in dominant frequency after erythromycin administration in Group II. The difference between Group I and II at particular time intervals was not significant but a diverse trend was evident. EGG recording enables us to register a gastric myoelectrical effect of prokinetic drugs. Erythromycin induced a significant increase in the dominant frequency of slow waves. DSS caused toxic injury to the porcine gastrointestinal tract responsible for the delayed and weaker myoelectrical effect of erythromycin in experimental animals.

• MeSH
• elektrofyziologické jevy účinky léků   MeSH
• elektromyografie metody   veterinární   MeSH
• erythromycin aplikace a dávkování   farmakologie   MeSH
• gastrointestinální látky aplikace a dávkování   farmakologie   MeSH
• gastrointestinální nemoci chemicky indukované   patofyziologie   MeSH
• gastrointestinální trakt účinky léků   zranění   MeSH
• modely u zvířat MeSH
• preklinické hodnocení léčiv MeSH
• síran dextranu MeSH
• Sus scrofa MeSH
• žaludek účinky léků   zranění   fyziologie   MeSH
• zvířata MeSH
• Check Tag
• ženské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

PURPOSE OF REVIEW: Critical illness myopathy and neuropathy are common complications in the ICU, causing limb and respiratory muscle weakness. We review the most recent data concerning their presentation, diagnosis and treatment. RECENT FINDINGS: Limb muscle strength can be reliably assessed by using the Medical Research Council scale or handgrip dynamometry. A Medical Research Council sum score below 48 or mean Medical Research Council score below 4 (antigravity strength) across all testable muscle groups, and a force value of less than 11 kg-force for men and less than 7 kg-force for women at dominant-hand dynamometry identify ICU-acquired weakness in previously healthy individuals admitted to an ICU for nonneuromuscular disorder. Clinical signs, together with measurements of the maximal inspiratory and expiratory pressures and vital capacity, are important to timely diagnose respiratory muscle weakness. Electrophysiological testing is usefully implemented in unconscious patients or in awake patients who do not improve despite appropriate treatments. Early physiotherapy in the ICU can increase the proportion of patients reaching an independent functional status following their ICU stay. Critical illness myopathy and neuropathy may occur outside the ICU; however, exact estimates are lacking. SUMMARY: Systematic application of diagnostic criteria and early physiotherapy may help clinicians to timely diagnose critical illness myopathy and neuropathy and to reduce the associated morbidity.

• Klíčová slova
• fyzioterapie, myopatie kriticky nemocných, neuropatie kriticky nemocných, stupnice Medical Research Council,
• MeSH
• elektrofyziologické jevy účinky léků   MeSH
• elektrofyziologie metody   MeSH
• elektromyografie MeSH
• fyzioterapie (techniky) využití   MeSH
• hyperglykemie prevence a kontrola   MeSH
• lidé MeSH
• péče o pacienty v kritickém stavu metody   metody   MeSH
• polyneuropatie diagnóza   etiologie   terapie   MeSH
• svalová slabost diagnóza   etiologie   terapie   MeSH
• Check Tag
• lidé MeSH

• MeSH
• biomedicínský výzkum MeSH
• elektroencefalografie metody   využití   MeSH
• elektrofyziologické jevy fyziologie   účinky léků   MeSH
• epilepsie * diagnóza   etiologie   MeSH
• evokované potenciály fyziologie   účinky léků   MeSH
• experimenty na zvířatech MeSH
• krysa rodu rattus MeSH
• mozková kůra * patologie   MeSH
• nervus ischiadicus * patofyziologie   patologie   MeSH
• zvířata MeSH
• Check Tag
• krysa rodu rattus MeSH
• zvířata MeSH