Wrodzony zespół wydłuzonego QT - aspekty diagnostyczne

Zespół wydłużonego QT charakteryzuje się zaburzeniami repolaryzacji z wydłużeniem czasu trwania odstępu QT w zapisie EKG i predyspozycją do groźnych komorowych arytmii (torsade de pointes) prowadzących do omdleń i nagłych zgonów. Na podstawie badań molekularnych za przyczynę zaburzeń elektrofizjologicznych występujących w tym zespole uznano defekty w białkach kanałów jonowych (potasowych i sodowych) błony komórkowej komórek mięśnia sercowego. Dziedziczony autosomalnie dominująco, bez wrodzonej głuchoty zespół Romano- -Warda jest zbiorem co najmniej 6 genotypów, z których najczęściej występują 3 pierwsze postacie LQTS1, LQTS2 i LQTS3. W zależności od położenia zmutowanego genu na chromosomie 11 (IKs), 7 (IKr) lub 3 (INa) te 3 genotypy różnią się między sobą zaburzeniami okresu repolaryzacji ze zmienną morfologią załamka T w zapisach elektrokardiograficznych oraz czynnikami wyzwalającymi objawową arytmię komorową. W obrazie klinicznym dominują nawracające utraty przytomności, które w LQTS1 i LQTS2 są najczęściej wywołane stymulacją układu adrenergicznego (wysiłek, emocje, przestrach, nagły bodziec dźwiękowy). W genotypie LQTS3 objawowa arytmia komorowa najczęściej występuje w spoczynku lub we śnie. U 40% pacjentów z wrodzonym zespołem wydłużonego QT przebieg kliniczny jest bezobjawowy. W postaciach LQTS klinicznie utajonych — wydłużenie odstępu QT, zmiany załamka T oraz komorowe zaburzenia rytmu serca — mogą występować napadowo, co można zaobserwować w zapisie Holtera lub w teście wysiłkowym. Często u pozornie zdrowych dzieci i młodzieży pierwszym objawem może być zatrzymanie krążenia lub nagły zgon. Młodzi pacjenci bez objawów powinni być objęci leczeniem profilaktycznym ze względu na możliwość występowania u nich epizodów nagłego zatrzymania krążenia, bez objawów poprzedzających. (Folia Cardiol. 2005; 12: 403–411

Dark Matter Directionality Detection performance of the Micromegas-based μ\muTPC-MIMAC detector

Directional Dark Matter Detection (DDMD) can open a new signature for Weakly Massive Interacting Particles (WIMPs) Dark Matter. The directional signature provides in addition, an unique way to overcome the neutron and neutrino backgrounds. In order to get the directional signature, the DDM detectors should be sensitive to low nuclear energy recoils in the keV range and have an angular resolution better than $20^{\circ}$. We have performed experiments with low energy ($<30\,\mathrm{keV}$) ion beam facilities to measure the angular distribution of nuclear recoil tracks in a MIMAC detector prototype. In this paper, we study angular spreads with respect to the electron drift direction ($0^{\circ}$ incident angle) of Fluorine nuclear tracks in this low energy range, and show nuclear recoil angle reconstruction produced by a monoenergetic neutron field experiment. We find that a high-gain systematic effect leads to a high angular resolution along the electron drift direction. The measured angular distribution is impacted by diffusion, and space charge or ion feedback effects, which can be corrected for by an asymmetry factor observed in the flash-ADC profile. The estimated angular resolution of the $0^{\circ}$ incident ion is better than $15^{\circ}$ at $10$ keV kinetic energy and agrees with the simulations within $20$%. The distributions from the nuclear recoils have been compared with simulated results based on a modified Garfield++ code. Our study shows that protons would be a more adapted target than heavier nuclei for DDMD of light WIMPs. We demonstrate that directional signature from the Galactic halo origin of a Dark Matter WIMP signal is experimentally achievable, with a deep understanding of the operating conditions of a low pressure detector with its diffusion mechanism.Comment: 19 pages, 12 figure

Me, My Girls, and the Ideal Hotel: Segmenting Motivations of the Girlfriend Getaway Market Using Fuzzy C-Medoids for Fuzzy Data.

Segmenting the motivation of travelers using the push and pull framework remains ubiquitous in tourism. This study segments the girlfriend getaway (GGA) market on motivation (push) and accommodation (pull) attributes and identifies relationships between these factors. Using a relatively novel clustering algorithm, the Fuzzy C-Medoids clustering for fuzzy data (FCM-FD), on a sample of 749 women travelers, three segments (Socializers, Enjoyers, and Rejoicers) are uncovered. The results of a multinomial fractional model show relationships between the clusters of motivation and accommodation attributes as well as sociodemographic characteristics. The research highlights the importance of using a gendered perspective in applying well established motivation models such as the push and pull framework. The findings have implications for both destination and accommodation management

Is Symptomatic Long QT Syndrome Associated with Depression in Women and Men?

We examined whether long QT syndrome (LQTS) mutation carrier status or symptomatic LQTS are associated with depression, and whether there are sex differences in these potential relationships. The sample comprised 782 participants (252 men). Of the 369 genetically defined LQTS mutation carriers, 169 were symptomatic and 200 were asymptomatic. The control group consisted of 413 unaffected relatives. Depression was assessed using the Beck Depression Inventory-II (BDI-II). No association was found for LQTS mutation carrier status with depression. The multinomial logistic regression showed that LQTS mutation carrier men with arrhythmic events scored higher on depression compared with the control group, even when adjusting for age, beta-blockers, antidepressants, and social support (OR = 1.09, 95 % CI [1.02, 1.15], p = .007). The binary logistic regression comparing symptomatic and asymptomatic LQTS mutation carriers showed that symptomatic LQTS was associated with depression in men (OR = 1.10, 95 % CI [1.03, 1.19], p = .009). The results were unchanged when additionally adjusted for education. These findings suggest that symptomatic LQTS is associated with depression in men but not in women. Overall, however, depression is more frequent in women than men. Thus, regular screening for depression in LQTS mutation carriers and their unaffected family members can be important.Peer reviewe

Trace metals and their relation to bacterial infections studied by X-ray microscopy

Bacterial pathogens survive in different environments in the human host by responding with expression of virulence factors that enable them to adapt to changing conditions. Trace elements regulate the expression of many virulence genes in bacteria and are thus important for their survival in the host. Mycobacteria are intracellular pathogens that can cause diseases such as tuberculosis or secondary infections in immunocompromised patients. We have used a hard x-ray microprobe to study the trace element distribution in the mycobacterial phagosome after infection of macrophages. We have studied phagosomes with virulent (M. avium) and nonvirulent (M. smegmatis) mycobacteria. In this article, we will show that the iron concentration in phagosomes with macrophages infected with nonvirulent M. smegmatis is reduced 24 hours after infection but increased in phagosomes in cells infected with virulent M. avium. In addition, we will show the effect activation of macrophages with tumor necrosis factor (TNF-$\alpha$) or interferon (IFN-$\gamma$) has on the iron concentration in M. avium.