Search for: pathophysiological
Total 56 records
Interpolation of orientation distribution functions in diffusion weighted imaging using multi-tensor model, Article Journal of Neuroscience Methods ; Volume 253 , 2015 , Pages 28-37 ; 01650270 (ISSN) ; Fatemizadeh, E ; Soltanian Zadeh, H ; Sharif University of Technology
Background: Diffusion weighted imaging (DWI) is a non-invasive method for investigating the brain white matter structure and can be used to evaluate fiber bundles. However, due to practical constraints, DWI data acquired in clinics are low resolution. New method: This paper proposes a method for interpolation of orientation distribution functions (ODFs). To this end, fuzzy clustering is applied to segment ODFs based on the principal diffusion directions (PDDs). Next, a cluster is modeled by a tensor so that an ODF is represented by a mixture of tensors. For interpolation, each tensor is rotated separately. Results: The method is applied on the synthetic and real DWI data of control and...
The effects of movement speed on kinematic variability and dynamic stability of the trunk in healthy individuals and low back pain patients, Article Clinical Biomechanics ; Volume 30, Issue 7 , Aug , 2015 , Pages 682-688 ; 02680033 (ISSN) ; Sanjari, M. A ; Mokhtarinia, H. R ; Moeini Sedeh, S ; Khalaf, K ; Parnianpour, M ; Sharif University of Technology
Elsevier Ltd 2015
Background: Comparison of the kinematic variability and dynamic stability of the trunk between healthy and low back pain patient groups can contribute to gaining valuable information about the movement patterns and neuromotor strategies involved in various movement tasks. Methods: Fourteen chronic low back pain patients with mild symptoms and twelve healthy male volunteers performed repeated trunk flexion-extension movements in the sagittal plane at three different speeds: 20 cycles/min, self-selected, and 40 cycles/min. Mean standard deviations, coefficient of variation and variance ratio as variability measures; maximum finite-time Lyapunov exponents and maximum Floquet multipliers as...
Fluid–structure interaction simulation of a cerebral aneurysm: effects of endovascular coiling treatment and aneurysm wall thickening, Article Journal of the Mechanical Behavior of Biomedical Materials ; Volume 74 , 2017 , Pages 72-83 ; 17516161 (ISSN) ; Nejad, M. A ; Saeedi, M ; Sharif University of Technology
In the present study, we investigate the effect of the hemodynamic factors of the blood flow on the cerebral aneurysms. To this end, a hypothetical geometry of the aneurysm in the circle of Willis, located in the bifurcation point of the anterior cerebral artery (ACA) and anterior communicating artery (ACoA) is modeled in a three-dimensional manner. Three cases are chosen in the current study: an untreated thin wall (first case), untreated thick wall (second case), and a treated aneurysm (third case). The effect of increasing the aneurysm wall thickness on the deformation and stress distribution of the walls are studied. The obtained results showed that in the second case, a reduction in the...
A regenerative approach towards recovering the mechanical properties of degenerated intervertebral discs: Genipin and platelet-rich plasma therapies, Article Proceedings of the Institution of Mechanical Engineers, Part H: Journal of Engineering in Medicine ; Volume 231, Issue 2 , 2017 , Pages 127-137 ; 09544119 (ISSN) ; Wang, J. L ; Abdollahi, M ; Hsu, Y. C ; Parnianpour, M ; Khalaf, K ; Sharif University of Technology
SAGE Publications Ltd 2017
Degenerative disc disease, associated with discrete structural changes in the peripheral annulus and vertebral endplate, is one of the most common pathological triggers of acute and chronic low back pain, significantly depreciating an individual's quality of life and instigating huge socioeconomic costs. Novel emerging therapeutic techniques are hence of great interest to both research and clinical communities alike. Exogenous crosslinking, such as Genipin, and platelet-rich plasma therapies have been recently demonstrated encouraging results for the repair and regeneration of degenerated discs, but there remains a knowledge gap regarding the quantitative degree of effectiveness and...
Detection and a possible link between parvovirus B19 and thyroid cancer, Article Tumor Biology ; Volume 39, Issue 6 , 2017 ; 10104283 (ISSN) ; Mostafaei, S ; Yari, K ; Ghasemi, A ; Chenar, H. M ; Moghoofei, M ; Sharif University of Technology
Human parvovirus B19 (B19) is a small, non-enveloped virus and belongs to Parvoviridae family. B19 persists in many tissues such as thyroid tissue and even thyroid cancer. The main aim of this study was to determine the presence of B19, its association with increased inflammation in thyroid tissue, and thus its possible role in thyroid cancer progression. Studies have shown that virus replication in non-permissive tissue leads to overexpression of non-structural protein and results in upregulation of proinflammatory cytokines such as interleukin 6 and tumor necrosis factor alpha. A total of 36 paraffin-embedded thyroid specimens and serum were collected from patients and 12 samples were used...
The effect of functional bracing on the arthrokinematics of anterior cruciate ligament injured knees during lunge exercise, Article Gait and Posture ; Volume 63 , 2018 , Pages 52-57 ; 09666362 (ISSN) ; Farahmand, F ; Esfandiarpour, F ; Golestanha, S. A ; Akbar, M ; Eskandari, A ; Mousavi, S. E ; Sharif University of Technology
Elsevier B.V 2018
Background: Functional knee braces are extensively used for partially and completely torn anterior cruciate ligament (ACL) patients and those who have undergone ACL graft reconstruction, in order to support the healing ACL, improve the joint's functional stability, and restore the normal joint kinematics. Research question: Does wearing braces alter the arthrokinematics of the ACL deficient knees during lung exercise? Methods: For ten male unilateral ACL deficient subjects, 3D knee models were reconstructed from CT images, acquired in rest position. Sagittal plane fluoroscopy was then performed throughout a complete cycle of lunge in braced and non-braced conditions. The 3D kinematics of the...
ECG fiducial point extraction using switching Kalman filter, Article Computer Methods and Programs in Biomedicine ; Volume 157 , 2018 , Pages 129-136 ; 01692607 (ISSN) ; Montazeri Ghahjaverestan, N ; Shamsollahi, M. B ; Jutten, C ; Sharif University of Technology
Elsevier Ireland Ltd 2018
In this paper, we propose a novel method for extracting fiducial points (FPs) of the beats in electrocardiogram (ECG) signals using switching Kalman filter (SKF). In this method, according to McSharry's model, ECG waveforms (P-wave, QRS complex and T-wave) are modeled with Gaussian functions and ECG baselines are modeled with first order auto regressive models. In the proposed method, a discrete state variable called “switch” is considered that affects only the observation equations. We denote a mode as a specific observation equation and switch changes between 7 modes and corresponds to different segments of an ECG beat. At each time instant, the probability of each mode is calculated and...
Translation and validation study of the Persian version of the Arthritis Impact Measurement Scales 2 (AIMS2) in patients with osteoarthritis of the knee, Article BMC Musculoskeletal Disorders ; Volume 10, Issue 1 , 2009 ; 14712474 (ISSN) ; Parnianpour, M ; Askary Ashtiani, A. R ; Hadian, M. R ; Rostamian, A ; Montazeri, A ; Sharif University of Technology
Background. The Arthritis Impact Measurement Scales 2 (AIMS2) has not been translated and validated for Persian-speaking patients with osteoarthritis of the knee. This was to provide a validated instrument to measure functional disability and health-related quality of life in patients with osteoarthritis of the knee in Iran. The aim of this study was to culturally adapt and validate the AIMS2 for Persian-speaking patients with osteoarthritis of the knee in Iran. Methods. A consecutive sample of patients with knee osteoarthritis were asked to complete the AIMS2, the Short Form Health Survey (SF-36) and four visual analog scales for pain, joint stiffness, patient's and physician's global...
The potential role of auditory prediction error in decompensated tinnitus: An auditory mismatch negativity study, Article Brain and Behavior ; Volume 9, Issue 4 , 2019 ; 21623279 (ISSN) ; Daneshi, A ; Asadpour, A ; Mohsen, S ; Farhadi, M ; Mahmoudian, S ; Sharif University of Technology
John Wiley and Sons Ltd 2019
Introduction: Some tinnitus subjects habituate to their tinnitus but some others do not and complain of its annoyance tremendously. Normal sensory memory and change detection processes are needed for detecting the tinnitus signal as a prediction error and habituation to tinnitus. The purpose of this study was to compare auditory mismatch negativity as the index of sensory memory and change detection among the studied groups to search for the factors involving in the perception of tinnitus and preventing habituation in decompensated tinnitus subjects. Methods: Electroencephalography was recorded from scalp electrodes in compensated tinnitus, decompensated tinnitus, and no tinnitus control...
Improvement of upper limb motor control and function after competitive and noncompetitive volleyball exercises in chronic stroke survivors: a randomized clinical trial, Article Archives of Physical Medicine and Rehabilitation ; Volume 100, Issue 3 , 2019 , Pages 401-411 ; 00039993 (ISSN) ; Azad, A ; Mehdizadeh, H ; Behzadipour, S ; Fakhar, M ; Taghavi Azar Sharabiani, P ; Parnianpour, M ; Taghizadeh, G ; Khalaf, K ; Sharif University of Technology
W.B. Saunders 2019
Objectives: To investigate the effects of competitive and noncompetitive volleyball exercises on the functional performance and motor control of the upper limbs in chronic stroke survivors. Design: Randomized clinical trial. Setting: Outpatient rehabilitation center. Participants: Chronic stroke survivors (N=48). Interventions: Participants were randomly assigned to competitive (n=16) or noncompetitive (n=16) volleyball exercise groups (60min/d volleyball exercise+30min/d traditional rehabilitation, 3d/wk for 7wk) and control group (n=16). Main Outcome Measures: Reach and grasp motor control measures were evaluated through kinematic analysis. Functional outcomes were assessed via Motor...
A stability-based model of a growing spine with adolescent idiopathic scoliosis: A combination of musculoskeletal and finite element approaches, Article Medical Engineering and Physics ; Volume 64 , 2019 , Pages 46-55 ; 13504533 (ISSN) ; Rouhi, G ; Arjmand, N ; Adeeb, S ; Sharif University of Technology
Elsevier Ltd 2019
Using a combined musculoskeletal and finite element (FE) approach, this study aimed to evaluate stability-based muscle forces in a spine with adolescent idiopathic scoliosis (AIS) as compared to a normal spine; and subsequently, determine the effects of stress distribution on the growth plates (GPs) of the growing spine. For this purpose a nonlinear 3D FE model of one normal and one scoliotic thoracolumbar spine, consisting of GPs attached to rigid L1 to L4 vertebrae, were developed using computed tomography images coupled with a growth modulation using the Stokes’ model. Corresponding well with recent in-vivo and in-vitro studies, results of the models predicted intradiscal pressures at the...
Association of glomerular and tubular dysfunction with glycaemic control, lipid, lipoprotein, apolipoprotein and antioxidant status in type 2 diabetes mellitus, Article Singapore Medical Journal ; Volume 48, Issue 9 , 2007 , Pages 840-846 ; 00375675 (ISSN) ; Djalali, M ; Siassi, F ; Farvid, S. S ; Sharif University of Technology
Singapore Medical Association 2007
Introduction: This study was conducted to investigate the relationship of glomerular and tubular dysfunctions with glycaemic control, lipid, lipoprotein, apolipoproteins and antioxidant status in 72 patients with type 2 diabetes mellitus. Methods: Urine albumin concentration was measured by immunoturbidimetric and urine N-acetyl-beta-D-glucosaminidase (NAG) and alanine aminopeptidase (AAP) activities with colorimetric methods. Glycated haemoglobin was measured using affinity chromatography. Erythrocyte glu ta thione reductase and glutathione peroxidase activities and serum levels of malondialdehyde, lipids, lipoproteins and apolipoproteins were determined in patients with type 2 diabetes...
Homozygous mutations in C14orf39/SIX6OS1 cause non-obstructive azoospermia and premature ovarian insufficiency in humans, Article American Journal of Human Genetics ; Volume 108, Issue 2 , 2021 , Pages 324-336 ; 00029297 (ISSN) ; Jiao, Y ; Khan, R ; Jiang, X ; Javed, A. R ; Ali, A ; Zhang, H ; Zhou, J ; Naeem, M ; Murtaza, G ; Li, Y ; Yang, G ; Zaman, Q ; Zubair, M ; Guan, H ; Zhang, X ; Ma, H ; Jiang, H ; Ali, H ; Dil, S ; Shah, W ; Ahmad, N ; Zhang, Y ; Shi, Q ; Sharif University of Technology
Cell Press 2021
Human infertility is a multifactorial disease that affects 8%–12% of reproductive-aged couples worldwide. However, the genetic causes of human infertility are still poorly understood. Synaptonemal complex (SC) is a conserved tripartite structure that holds homologous chromosomes together and plays an indispensable role in the meiotic progression. Here, we identified three homozygous mutations in the SC coding gene C14orf39/SIX6OS1 in infertile individuals from different ethnic populations by whole-exome sequencing (WES). These mutations include a frameshift mutation (c.204_205del [p.His68Glnfs∗2]) from a consanguineous Pakistani family with two males suffering from non-obstructive...
Rhythmic air-puff into nasal cavity modulates activity across multiple brain areas: A non-invasive brain stimulation method to reduce ventilator-induced memory impairment, Article Respiratory Physiology and Neurobiology ; Volume 287 , 2021 ; 15699048 (ISSN) ; Salimi, M ; Nazari, M ; Garousi, M ; Tabasi, F ; Dehdar, K ; Salimi, A ; Jamaati, H ; Mirnajafi Zadeh, J ; Arabzadeh, E ; Raoufy, M. R ; Sharif University of Technology
Elsevier B.V 2021
Mechanical ventilation (MV) can result in long-term brain impairments that are resistant to treatment. The mechanisms underlying MV-induced brain function impairment remain unclear. Since nasal airflow modulates brain activity, here we evaluated whether reinstating airflow during MV could influence the memory performance of rats after recovery. Rats were allocated into two study groups: one group received rhythmic air-puff into the nasal cavity during MV and a control group that underwent ventilation without air-puff. During MV, air-puffs induced time-locked event potentials in OB, mPFC and vHPC and significantly increased the oscillatory activity at the air-puff frequency. Furthermore, in...
Search for critical loading condition of the spine-A meta analysis of a nonlinear viscoelastic finite element model, Article Computer Methods in Biomechanics and Biomedical Engineering ; Volume 8, Issue 5 , 2005 , Pages 323-330 ; 10255842 (ISSN) ; Shirazi Adl, A ; Parnianpour, M ; Sharif University of Technology
The relative vulnerability of spinal motion segments to different loading combinations remains unknown. The meta-analysis described here using the results of a validated L2-L3 nonlinear viscoelastic finite element model was designed to investigate the critical loading and its effect on the internal mechanics of the human lumbar spine. A Box-Behnken experimental design was used to design the magnitude of seven independent variables associated with loads, rotations and velocity of motion. Subsequently, an optimization method was used to find the primary and secondary variables that influence spine mechanical output related to facet forces, disc pressure, ligament forces, annulus matrix...
Recent advances in the design and applications of amyloid-β peptide aggregation inhibitors for Alzheimer’s disease therapy, Article Biophysical Reviews ; Volume 11, Issue 6 , 2019 , Pages 901-925 ; 18672450 (ISSN) ; Khazaei, S ; Behnammanesh, H ; Shamloo, A ; Erfani, M ; Beiki, D ; Bavi, O ; Sharif University of Technology
Alzheimer’s disease (AD) is an irreversible neurological disorder that progresses gradually and can cause severe cognitive and behavioral impairments. This disease is currently considered a social and economic incurable issue due to its complicated and multifactorial characteristics. Despite decades of extensive research, we still lack definitive AD diagnostic and effective therapeutic tools. Consequently, one of the most challenging subjects in modern medicine is the need for the development of new strategies for the treatment of AD. A large body of evidence indicates that amyloid-β (Aβ) peptide fibrillation plays a key role in the onset and progression of AD. Recent studies have reported...