TAIMAN (TAI), the only insect ortholog of mammalian Steroid Receptor Coactivators (SRCs), is a critical modulator of ecdysone and juvenile hormone (JH) signaling pathways, which govern insect development and reproduction. The modulatory effect is mediated by JH-dependent TAI's heterodimerization with JH receptor Methoprene-tolerant and association with the Ecdysone Receptor complex. Insect hormones regulate insect physiology and development in concert with abiotic cues, such as photo- and thermoperiod. Here we tested the effects of JH and ecdysone signaling on the circadian clock by a combination of microsurgical operations, application of hormones and hormone mimics, and gene knockdowns in the linden bug Pyrrhocoris apterus males. Silencing taiman by each of three non-overlapping double-strand RNA fragments dramatically slowed the free-running period (FRP) to 27-29 hours, contrasting to 24 hours in controls. To further corroborate TAIMAN's clock modulatory function in the insect circadian clock, we performed taiman knockdown in the cockroach Blattella germanica. Although Blattella and Pyrrhocoris lineages separated ~380 mya, B. germanica taiman silencing slowed the FRP by more than 2 hours, suggesting a conserved TAI clock function in (at least) some insect groups. Interestingly, the pace of the linden bug circadian clock was neither changed by blocking JH and ecdysone synthesis, by application of the hormones or their mimics nor by the knockdown of corresponding hormone receptors. Our results promote TAI as a new circadian clock modulator, a role described for the first time in insects. We speculate that TAI participation in the clock is congruent with the mammalian SRC-2 role in orchestrating metabolism and circadian rhythms, and that TAI/SRCs might be conserved components of the circadian clock in animals.
Sensitivity to magnetic fields is dependent on the intensity and color of light in several animal species. The light-dependent magnetoreception working model points to cryptochrome (Cry) as a protein cooperating with its co-factor flavin, which possibly becomes magnetically susceptible upon excitation by light. The type of Cry involved and what pair of magnetosensitive radicals are responsible is still elusive. Therefore, we developed a conditioning assay for the firebug Pyrrhocoris apterus, an insect species that possesses only the mammalian cryptochrome (Cry II). Here, using the engineered Cry II null mutant, we show that: (i) vertebrate-like Cry II is an essential component of the magnetoreception response, and (ii) magnetic conditioning continues even after 25 h in darkness. The light-dependent and dark-persisting magnetoreception based on Cry II may inspire new perspectives in magnetoreception and cryptochrome research.
- MeSH
- čití, cítění MeSH
- hmyz MeSH
- kryptochromy * genetika MeSH
- magnetické pole * MeSH
- tma MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Hypokalcemie je vzácnou, avšak potenciálně reverzibilní příčinou dilatační kardiomyopatie. Nejčastěji je způsobena hypoparathyreózou. V následující kazuistice je popsán případ 74letého pacienta s dilatační kardiomyopatií, která byla vyvolána dlouhodobou hypokalcemií. Po substituci kalcia se zdravotní stav pacienta zlepšil, ustoupily známky srdečního selhání a kontraktilní funkce komor se zlepšila.
Hypocalcemia is a rare, yet potentially reversible cause of dilated cardiomyopathy, with the most frequent underlying cause being hypoparathyroidism. This case report presents the case of a 74-year-old patient with dilated cardiomyopathy developing due to long-term hypocalcemia. Following calcium supplementation, the patient's condition improved as did ventricular contractile function, and signs of heart failure resolved.
It is known that the circadian clock in Drosophila can be sensitive to static magnetic fields (MFs). Man-made radiofrequency (RF) electromagnetic fields have been shown to have effects on animal orientation responses at remarkably weak intensities in the nanotesla range. Here, we tested if weak broadband RF fields also affect the circadian rhythm of the German cockroach (Blatella germanica). We observed that static MFs slow down the cockroach clock rhythm under dim UV light, consistent with results on the Drosophila circadian clock. Remarkably, 300 times weaker RF fields likewise slowed down the cockroach clock in a near-zero static magnetic field. This demonstrates that the internal clock of organisms can be sensitive to weak RF fields, consequently opening the possibility of an influence of man-made RF fields on many clock-dependent events in living systems.
- MeSH
- cirkadiánní hodiny * MeSH
- Drosophila MeSH
- Ectobiidae * MeSH
- rádiové vlny * MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Diverse animal species perceive Earth's magnetism and use their magnetic sense to orientate and navigate. Even non-migrating insects such as fruit flies and cockroaches have been shown to exploit the flavoprotein Cryptochrome (Cry) as a likely magnetic direction sensor; however, the transduction mechanism remains unknown. In order to work as a system to steer insect flight or control locomotion, the magnetic sense must transmit the signal from the receptor cells to the brain at a similar speed to other sensory systems, presumably within hundreds of milliseconds or less. So far, no electrophysiological or behavioral study has tackled the problem of the transduction delay in case of Cry-mediated magnetoreception specifically. Here, using a novel aversive conditioning assay on an American cockroach, we show that magnetic transduction is executed within a sub-second time span. A series of inter-stimulus intervals between conditioned stimuli (magnetic North rotation) and unconditioned aversive stimuli (hot air flow) provides original evidence that Cry-mediated magnetic transduction is sufficiently rapid to mediate insect orientation.
- Publikační typ
- časopisecké články MeSH
The ability to perceive geomagnetic fields (GMFs) represents a fascinating biological phenomenon. Studies on transgenic flies have provided evidence that photosensitive Cryptochromes (Cry) are involved in the response to magnetic fields (MFs). However, none of the studies tackled the problem of whether the Cry-dependent magnetosensitivity is coupled to the sole MF presence or to the direction of MF vector. In this study, we used gene silencing and a directional MF to show that mammalian-like Cry2 is necessary for a genuine directional response to periodic rotations of the GMF vector in two insect species. Longer wavelengths of light required higher photon fluxes for a detectable behavioral response, and a sharp detection border was present in the cyan/green spectral region. Both observations are consistent with involvement of the FADox, FAD(•-) and FADH(-) redox forms of flavin. The response was lost upon covering the eyes, demonstrating that the signal is perceived in the eye region. Immunohistochemical staining detected Cry2 in the hemispherical layer of laminal glia cells underneath the retina. Together, these findings identified the eye-localized Cry2 as an indispensable component and a likely photoreceptor of the directional GMF response. Our study is thus a clear step forward in deciphering the in vivo effects of GMF and supports the interaction of underlying mechanism with the visual system.
- MeSH
- fenotyp MeSH
- fotoreceptory bezobratlých metabolismus účinky záření MeSH
- kryptochromy metabolismus MeSH
- magnetické pole * MeSH
- složené oko členovců účinky záření MeSH
- švábi metabolismus účinky záření MeSH
- ultrafialové záření MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Nejčastější poruchou srdečního rytmu je fibrilace síní. V každodenní klinické praxi musíme řešit jak nejlépe zasáhnout u pacientů, kteří k nám přicházejí s touto diagnózou. Náš postup závisí zvláště na symptomech arytmie a délce trvání arytmie. U pacientů těžce symptomatických s projevy srdečního selhávání či koronární insuficience volíme hospitalizaci, u zbylých pacientů můžeme postupovat ambulantně. V obou případech se musíme rozhodnout, zda budeme volit kontrolu rytmu, tj. farmakologickou nebo elektrickou kardioverzi, či kontrolu tepové frekvence. Obě strategie mají ve skupině starších a méně symptomatických pacientů podle posledních studií (AFFIRM, PIAF, RACE) rovnocennou prognózu. Osvědčenou, účinnou a bezpečnou metodou kontroly rytmu je provedení elektrické kardioverze, která má své nezastupitelné místo i v době rozmachu radiofrekvenčních ablací. Autoři prezentují soubor pacientů, u kterých byla v průběhu jednoho kalendářního roku ambulantně provedena elektrická kardioverze.
The most common arrhythmia is atrial fibrillation. In the outpatient clinic we have to deal with and treat patients attending with this diagnosis as best we can on a routine daily basis. Our procedure and method of treatment depends mainly on the symptoms and time of onset and duration of atrial fibrillation. Patients with symptoms of heart failure and coronary insufficiency are admitted to the coronary unit, whilst the remaining patients with less severe symptoms can be treated in Day Care Unit. In both cases, we have to make a decision if the method of treatment is to control the rhythm (i.e. pharmacologically or electrical cardioversion) or control the heart rate. In a group of elderly and less symptomatic patients both strategies have equal outcomes according to the latest studies. Synchronized electrical cardioversion offers a reliable, effective and safe control and treatment of rhythm; it is still the treatment of choice despite the recent boom in radiofrequency ablations. The article presents a sample of patients treated with electrical cardioversion in the outpatient clinic over the course of one calendar year.
Autoři předkládají analýzu Jihočeského koronárního registru (JKR), který mapuje reálnou léčbu infarktu myokardu s ST elevacemi (STEMI) nejen v centrálním kardiocentru, ale v celém Jihočeském regionu. V roce 2003 bylo v regionu přijato do nemocnic 599 pacientů s diagnózou STEMI. Z toho 464 pacientů bylo léčeno v kardiocentru (KC) – 162 pacientů bylo přímo ze spádu KC, 302 nemocných (65 %) bylo odesláno z komunitních nemocnic k direktní angioplastice (dPCI) na vzdálenost 27–93 km. Celková hospitalizační mortalita na STEMI byla v KC 7,5 %, v celém regionu 11,3 %. U pacientů, kterým byla direktní PCI provedena do 24 hodin po vzniku potíží, byla hospitalizační mortalita 4,6 %. Autoři ve shodě s literárními údaji prokazují závislost úmrtnosti na časovém intervalu bez léčby od vzniku potíží. Direktní PCI bylo léčeno 74 % všech pacientů z regionu, u 5 % pacientů byla aplikována trombolytická léčba, akutní kardiochirurgický výkon podstoupilo 1 % nemocných a zbylých 20 % nemocných bylo léčeno konzervativně bez pokusu o reperfuzní léčbu – většinou z důvodů časových. Poměr reperfuzní léčby dPCI k trombolýze je v rámci celého regionu 93 % vs. 7 %. U pacientů léčených dPCI nebyl statisticky významný rozdíl v mortalitě mezi pacienty primárně přijatými do KC a pacienty odeslanými z komunitních nemocnic (5,0 % vs. 7,3 %, P = NS). Závěr: Přímá angioplastika je dominantní metodou léčby STEMI v Jihočeském regionu.
The authors present the analysis of the South Bohemian Coronary Registry which maps real-life treatment of ST-elevation myocardial infarction (STEMI) not only in the central cardiocenter but throughout the whole South Bohemian region. In 2003, total of 599 patients with diagnosed STEMI were admitted to the hospitals within the region. Out of this 464 patients were treated in the cardiocenter (CC): 162 patients directly from the cardiocenter referal area, 302 patients (65 %) were transferred from community hospitals to direct angioplasty (dPCI) from the distance 27–93 km. The overall in-hospital mortality in the STEMI patients was 7.5 % in the cardiocenter alone, in the whole region 11.3 %. In patients where direct PTCA was performed within 24 hours after symptoms onset, hospital mortality was 4.6 %. Authors in agreement with literature document the relationship between mortality and time from symptoms onset to treatment. Direct PCI was performed in 74 % of all patients in the region, 5 % of patients received thrombolytic therapy, acute surgical intervention undervent 1 % of patients and 20 % of patients were treated only medically without any attemt of reperfusion therapy – mostly due to time limitations. Reperfusion therapy ratio of dPCI versus thrombolysis within the whole region is 93 % vs. 7 %. In the group treated with dPCI there was no significant difference in mortality of patients primarilly admitted to the CC and patients transferred from community hospitals (5.0 % vs. 7.3 %, P = NS). Conclusion: Direct angioplasty is a dominant method of STEMI treatment in the South Bohemian region.
- MeSH
- balónková koronární angioplastika MeSH
- dospělí MeSH
- elektrokardiografie metody MeSH
- infarkt myokardu diagnóza mortalita terapie MeSH
- lidé MeSH
- nemocnice krajské MeSH
- registrace MeSH
- transport pacientů MeSH
- trombolytická terapie metody MeSH
- Check Tag
- dospělí MeSH
- lidé MeSH
- mužské pohlaví MeSH
- ženské pohlaví MeSH
