University of Medical science
University of Medical science
Tekieh T.,Institute for Research in Fundamental Sciences |
Rafii-Tabar H.,University of Medical science |
Sasanpour P.,Shahid Beheshti University of Medical Sciences
IECBES 2016 - IEEE-EMBS Conference on Biomedical Engineering and Sciences | Year: 2016
We have theoretically studied the effect of swelling of axons on the electrophysiological properties of action potential propagation. The modified cable equation is solved numerically by considering the deformation and abnormalities in the axon's geometry. The result shows that the broadening of action potential pulses, amplitudes and the latency of the action potential are all affected. The extent of influence depends on the morphology and structure of the swell. In some geometry, the swell structure leads to irregularity in the shape of the action potential and steep variations in the transmembrane potential. © 2016 IEEE.
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.
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.
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.
Orazizadeh M.,University of Medical science |
Khorsandi L.S.,University of Medical science |
Hashemitabar M.,University of Medical science
Andrologia | Year: 2010
Exposure to glucocorticoids (GCs) leads to numerous changes in various biological systems including the reproductive system. This work evaluated effects of dexamethasone (Dex), a widely used GC, on mouse testicular germ cells. Experimental groups (E1-E3) received one of the following treatments daily for 7 days: 4, 7 and 10 mg kg-1 Dex respectively. Control groups were treated with equivalent volumes of saline. Testicular histopathology, morphometric analysis and deoxy-UTP-digoxigenin nick end labeling (TUNEL) assessment were performed for evaluation of the toxic effects of Dex and detection of the apoptotic cells. The results showed that Dex induces histopathological alterations such as epithelial vacuolisation, atrophy and reduction in testicular spermatozoid. Morphometrical data showed that Dex significantly reduced tubular diameter and epithelial height (P < 0.05). Johnsen's scoring also showed poor spermatogenesis in E2 and E3 groups (P < 0.05). Apoptotic index of germ cells was significantly increased in E2 (18.9% versus 1.76%, P < 0.01) and E3 (24.6 versus 1.76%, P < 0.001) groups. It is concluded that Dex acts as testicular toxicant and that further studies are needed to establish its mechanism of action upon spermatogenesis. © 2010 Blackwell Verlag GmbH.
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.
Entezari M.,University of Medical science |
Dabaghian F.,University of Medical science |
Hashemi M.,Islamic Azad University at Tehran Medical
Journal of Cancer Research and Therapeutics | Year: 2014
Background: Cancer is one of the main causes of mortality in the world which is created by the effect of enviromental physico-chemical mutagen and carcinogen agents. In the last years, many studies have been performed on the anticancer effects of flavonoids. Echinophora platyloba DC plant (Khousharizeh) is one of the indigenous medicinal plants which is used as a food seasoning and medicine in Iran. Materials and Methods: The extract was evaluated in terms of antimutagenicity properties by a standard reverse mutation assay (Ames Test). This was performed with histidine auxotroph strain of Salmonella typhimurium (TA100). Thus, it requires histidine from a foreign supply to ensure its growth. The afore mentioned strain gives rise to reverted colonies when expose to carcinogen substance (Sodium Azide). The other objective of this study was to examine the in vitro cytotoxic activity of cell death of crude methanolic extracts prepared from Echinophora platyloba on Acute Promyelocytic Leukemia cell line (NB4). Cytotoxicity and viability of methanolic extract was assessed by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) and dye exclusion assay. Results: In Ames test the extract prevented the reverted mutations and the hindrance percent was 93.4% in antimutagenicity test. Data obtained from this assay indicated that the extract significantly reduced the viability of NB4 cells and inhibited cell growth in a dose dependent manner. Conclusion: This study demonstrates the antimutagenicity effect of Echinophora Platyloba and suggests that it has a potential as an anticancer agent.
Jahanshahi G.,University of Medical science
Quintessence international (Berlin, Germany : 1985) | Year: 2010
OBJECTIVE: Oral lichen planus (OLP) is a chronic mucocutaneous disease with unknown etiology. Oral lichenoid reactions (OLRs) comprise a family of lesions with different recognized etiologies. OLR lesions have clinical and histopathologic characteristics similar to those of OLP, although their management is different from that for OLP. Discrimination between OLP and OLR has always been a major challenge for both clinicians and pathologists. For this purpose, this study evaluated mast cells in the lamina propria of OLP and OLR lesional tissues. METHOD AND MATERIALS: The study was performed on 23 cases of OLP and 23 cases of OLR categorized based on clinical examination, histopathology evaluation, and history in accordance with WHO definitions of OLP. Mast cells in the reticular layer of the lamina propria for OLP and OLR lesions were evaluated both quantitatively (total number) and qualitatively (degranulation status) using light microscopy. Two staining methods-toluidine blue (histochemistry) and antitryptase (immunohistochemistry)-were used for identification and mapping of the mast cells. RESULTS: No significant difference was observed in the total number of mast cells between the two disease groups (P = .74 toluidine blue, P = .47 antitryptase). A statistically significant difference was noted between the number of degranulated mast cells of OLP and OLR lesions with only toluidine blue stain (P < .001 toluidine blue, P = .14 antitryptase). A statistically significant difference in the ratio of degranulated mast cells to the total population was observed between OLP and OLR lesions with both staining methods (P < .001 for both methods). CONCLUSION: The observed difference in the ratio of degranulated to total mast cell population in the reticular zone of the lamina propria may be a useful criterion for histopathologic distinction between OLP and OLR. This may also explain the different therapeutic approaches toward these two lesions.
Ghiasi H.,University of Medical science
Reports of Practical Oncology and Radiotherapy | Year: 2014
Aim: The aim of this work was to map the characteristics of (n,. γ) and (γ,. n) reactions in a high energy photon radiation therapy. Background: Photoneutrons produced in the high energy X-Ray radiation therapy may damage patients and staff. It is due to high RBE of the produced neutrons according to their energy and isotropic emission. Characterization of the photoneutrons can help us in appropriate shielding. Materials and methods: This study focused on the photoneutron and capture gamma ray phenomena. Characteristics such as dose value, fluence and spectra of both the neutrons and the by produced prompt gamma ray were described. Results and discussion: Neutron and prompt gamma spectra in different points showed the neutrons to be thermalized when increasing the distance from the linac. Energy of the neutrons changed from about 0.6MeV at the isocentre to around 10-08MeV at the outer door position. Although the neutrons were found as fast neutrons, their spectra showed they were thermal neutrons at the outer door position. Additionally, it was seen that the energy of the gamma rays is higher than the scattered X-ray energy. The energy of gamma rays was seen to be up to 10MeV while the linac photons had energy lower than 1MeV. Neutron source strength obtained in this work was in good agreement with the published data, which may be a confirmation of our simulation accuracy. Conclusion: The study showed that the Monte Carlo simulation can be applied in the radiotherapy and industrial radiation works as a useful and precise estimator. We also concluded that the dose from the prompt gamma ray at the outer door location is higher than the scattered radiation from the linac and should be considered in the shielding. © 2013 Greater Poland Cancer Centre.