Time filter

Source Type

Ohno S.,Kyoto University | Makiyama T.,Kyoto University | Doi T.,Kyoto University | Shizuta S.,Kyoto University | And 4 more authors.
Circulation: Arrhythmia and Electrophysiology | Year: 2011

Background-Brugada syndrome (BrS) has a significantly higher incidence among the male sex. Among genes coding ion channels and their modulatory proteins, KCNE5 (KCNE1L) is located in the X chromosome and encodes an auxiliary β-subunit for K channels. KCNE5 has been shown to modify the transient outward current (Ito), which plays a key role in determining the repolarization process in the myocardium. This study investigated whether KCNE5 mutations could be responsible for BrS and other idiopathic ventricular fibrillation (IVF). Methods and Results-In 205 Japanese patients with BrS or IVF who tested negative for SCN5A mutation, we conducted a genetic screen for KCNE5 variants. We identified 2 novel KCNE5 variants: p.Y81H in 3 probands and p.[D92E;E93X] in 1 proband from 4 unrelated families. Y81H was identified in 1 man and 2 women; D92E;E93X was found in a 59-year-old man. All probands received implantable cardioverter-defibrillators. Functional consequences of the KCNE5 variants were determined through biophysical assay using cotransfection with KCND3 or KCNQ1. In the experiments with KCND3, which encodes Kv4.3, I to was significantly increased for both KCNE5 variants compared to wild type. In contrast, there were no significant changes in current properties reconstructed by KCNQ1+wild type KCNE5 and the 2 variants. With the simulation model, both variants demonstrated notch-and-dome or loss-of-dome patterns. Conclusions-KCNE5 modulates Ito, and its novel variants appeared to cause IVF, especially BrS, in male patients through gain-of-function effects on Ito. Screening for KCNE5 variants is relevant for BrS or IVF. © 2011 American Heart Association, Inc.

Resalat S.N.,University of Tehran | Saba V.,University of Medical science | Afdideh F.,Sharif University of Technology | Heidarnejad A.,University of Tehran
Proceedings - IEEE-EMBS International Conference on Biomedical and Health Informatics: Global Grand Challenge of Health Informatics, BHI 2012 | Year: 2012

Brain Computer Interface provides a new communication channel for people who have severe brain injuries. Among different types of BCIs, SSVEP-based one has been focused in recent years. In this type of BCI, selection of twinkling frequency of external visual stimulant and the distance between stimulants (in case of more than one stimulant) is so important. In this work, a SSVEP-based BCI with two external stimulants was designed. In order to determine the best twinkling frequency of stimulants and the best distance between them, the classification accuracy for seven different twinkling frequency pairs and five different stimulants distances was calculated. Two methods for feature extraction step were proposed and the Max classifier was used for classification in order to speed up the computational burden of classification step. Features were extracted from four different segment lengths (sweeps). The results showed that nearly in all sweeps and all inter-sources distances the frequency pair of 10-15 Hz has the highest classification accuracy among other frequency pairs, which is 92% in the inter-sources distance of 24 cm and sweep length of 3 seconds. In addition, the results demonstrated that the method 2 feature extraction technique outperforms the method 1. In addition, for determining the best sweep length, Information Transfer Rate (ITR) was computed and the results indicated that the sweep length of 0.5 second has the highest ITR, so would be practical in real-time applications of BCI. © 2012 IEEE.

Mazloom R.,Tarbiat Modares University | Eftekhari G.,Tarbiat Modares University | Rahimi M.,Tehran University of Medical Sciences | Khori V.,University of Medical science | And 3 more authors.
PLoS ONE | Year: 2013

Previous reports have indicated that artificial stimulation of the vagus nerve reduces systemic inflammation in experimental models of sepsis. This phenomenon is a part of a broader cholinergic anti-inflammatory pathway which activates the vagus nerve to modulate inflammation through activation of alpha7 nicotinic acetylcholine receptors (α7nACHR). Heart rate variability represents the complex interplay between autonomic nervous system and cardiac pacemaker cells. Reduced heart rate variability and increased cardiac cycle regularity is a hallmark of clinical conditions that are associated with systemic inflammation (e.g. endotoxemia and sepsis). The present study was aimed to assess the role of α7nACHR in modulation of heart rate dynamics during systemic inflammation. Systemic inflammation was induced by injection of endotoxin (lipopolysaccharide) in rats. Electrocardiogram and body temperature were recorded in conscious animals using a telemetric system. Linear and non-linear indices of heart rate variability (e.g. sample entropy and fractal-like temporal structure) were assessed. RT-PCR and immunohistochemistry studies showed that α7nACHR is expressed in rat atrium and is mainly localized at the endothelial layer. Systemic administration of an α7nACHR antagonist (methyllycaconitine) did not show a significant effect on body temperature or heart rate dynamics in naïve rats. However, α7nACHR blockade could further reduce heart rate variability and elicit a febrile response in endotoxemic rats. Pre-treatment of endotoxemic animals with an α7nACHR agonist (PHA-543613) was unable to modulate heart rate dynamics in endotoxemic rats but could prevent the effect of endotoxin on body temperature within 24 h experiment. Neither methyllycaconitine nor PHA-543613 could affect cardiac beating variability of isolated perfused hearts taken from control or endotoxemic rats. Based on our observations we suggest a tonic role for nicotinic acetylcholine receptors in modulation of heart rate dynamics during systemic inflammation. © 2013 Mazloom et al.

Bahrami P.,Lorestan University of Medical Sciences | Zebardast H.,Lorestan University of Medical Sciences | Zibaei M.,Lorestan University of Medical Sciences | Mohammadzadeh M.,University of Medical science | Zabandan N.,Clinical Research Institute
Pain Physician | Year: 2012

Background: Headache is a prevalent and disabling condition affecting people in all age groups worldwide, leading to low job performance and quality of life with a significant economic burden on societies. Objective: We evaluated headache prevalence and characteristics and some probable associated factors in patients referring to neurology specialist clinics. Study Design: Cross sectional study Setting: Clinics of Khoramabad and also those referring to the emergency department of Khoramabad University Hospital. Methods: One thousand patients with a chief concern of headache were assigned to the study. All patients filled out a structured questionnaire to gather demographic information and data on headache characteristics and associated factors, including past medical and psychiatric history, history of oral contraceptive pill (OCP) use, nonsteroidal anti-inflammatory drug (NSAID) overuse, and menstruation. Results: The total prevalence of primary headaches was 78.2%, with migraine (with and without aura) being the most prevalent type with a prevalence of 41.6% followed by tension type headache found in 31.6% of the study population. Primary headaches were significantly more common in women and younger age groups. Factors found associated with a significantly higher prevalence of primary headaches were lower economic level, higher educational level, occupation, OCP use and NSAIDs overuse. Secondary headaches, with a total prevalence of 20.1%, significantly increased in older age groups and higher economic levels and were significantly less prevalent in higher educational levels. Limitations: The study population is not quite representative of the general population of Iran. Conclusion: Results highlight the impact of socioeconomic factors on headache epidemiology in a developing country and demonstrate that OCPs and NSAIDs overuse might have an effect on the distribution of primary headaches. Further multicenter studies are needed to evaluate headache epidemiology in the whole country.

Ghaemi E.,University of Medical science
Journal of Clinical and Diagnostic Research | Year: 2011

The aim of this study was to find out the prevalence of CEA elevation among subjects, regardless of the contradictory arguments about the senstivity and specificity of this tumor marker. Carcinoemroyonic antigen (CEA) is a tumor marker widely practiced to screen, diagnose, monitor and follow-up patients with gastrointestinal, and particularly colorectal tumor. This tumor marker is not a specific antigen for colorectal carcinoma and its concentration may be elevated in other forms of carcinomas, such as breast, ovary liver and pancreas, but still its elevated serum concentration is a valuable index widely used in clinical practice for gastrointestinal carcinogen. The data for this retrospective study obtained from data base of Danesh medical diagnostic laboratory in Gorgan located in northern Iran. The conclusion of the findings of this investigation indicated that 17.39% suspected patients had tumor marker for a particular carcinoma, the CEA elevated level should be considered either for tumor or its recurrence. The findings of this study indicated that even among all controversial arguments about CEA as a specific and alarming tool to both the patients and clinician, which is the least contribution CEA level can offer in cancer patient management.

Discover hidden collaborations