Search for: pathophysiological
Total 56 records
The effect of angle and level of exertion on trunk neuromuscular performance during multidirectional isometric activities, Article Spine ; Volume 34, Issue 5 , 2009 , Pages E170-E177 ; 03622436 (ISSN) ; Olyaei, G. R ; Talebian, S ; Sanjari, M. A ; Parnianpour, M ; Sharif University of Technology
STUDY DESIGN.: To quantify trunk muscle capability and controllability in different angles and levels of isometric exertion using a torque tracking system. OBJECTIVE.: To investigate the effect of biaxial isometric exertions on the maximum capability of trunk and to examine the effect of angle and level of isometric exertion on trunk controllability during the tracking task in upright posture. SUMMARY OF BACKGROUND DATA.: Combined motions of trunk at varying exertion levels occur in most daily and occupational activities and are important risk factors of low back pain. Few studies have investigated trunk capability and controllability during multidirectional activities with different...
Time-course investigation of postural sway variability: Does anxiety exacerbate the sensory reweighting impairment in chronic stroke survivors?, Article Neuropsychologia ; Volume 127 , 2019 , Pages 185-194 ; 00283932 (ISSN) ; Azad, A ; Mehdizadeh, H ; Doostdar, A ; Hoseinpour, F ; Mehdizadeh, M ; Niazi Khatoon, J ; Shokouhyan, M. R ; Parnianpour, M ; Taghizadeh, G ; Khalaf, K ; Sharif University of Technology
Elsevier Ltd 2019
Although anxiety is one of the most prevalent psychological disorders in stroke survivors, its effect on sensory reweighting has not yet been fully studied. The aim of this work was to investigate how anticipation of collision avoidance events affects sensory reweighting in chronic stroke survivors with low and high levels of anxiety (LA-stroke and HA-stroke, respectively), as compared with healthy controls (HC), under the condition of perturbed proprioception. Eighteen LA-stroke and 18 HA-stroke survivors, as well as 18 gender- and age-matched HC, participated in this study. Postural sway variability (i.e. Root Mean Square (RMS) of the COP velocity) was measured for a duration of 180 s...
Urine and serum NMR-based metabolomics in pre-procedural prediction of contrast-induced nephropathy, Article Internal and Emergency Medicine ; Volume 15, Issue 1 , 2020 , Pages 95-103 ; Chashmniam, S ; Khoormizi, S. M. H ; Salehi, L ; Jamalian, S. A ; Nafar, M ; Kalantari, S ; Sharif University of Technology
Contrast induced nephropathy (CIN) has been reported to be the third foremost cause of acute renal failure. Metabolomics is a robust technique that has been used to identify potential biomarkers for the prediction of renal damage. We aim to analyze the serum and urine metabolites changes, before and after using contrast for coronary angiography, to determine if metabolomics can predict early development of CIN. 66 patients undergoing elective coronary angiography were eligible for enrollment. Urine and serum samples were collected prior to administration of CM and 72 h post procedure and analyzed by nuclear magnetic resonance. The significant differential metabolites between patients who...
A multi-scale model for determining the effects of pathophysiology and metabolic disorders on tumor growth, Article Scientific Reports ; Volume 10, Issue 1 , 20 February , 2020 ; Firoozabadi, B ; Mozafari, A ; Munn, L. L ; Sharif University of Technology
Nature Research 2020
The search for efficient chemotherapy drugs and other anti-cancer treatments would benefit from a deeper understanding of the tumor microenvironment (TME) and its role in tumor progression. Because in vivo experimental methods are unable to isolate or control individual factors of the TME and in vitro models often do not include all the contributing factors, some questions are best addressed with systems biology mathematical models. In this work, we present a new fully-coupled, agent-based, multi-scale mathematical model of tumor growth, angiogenesis and metabolism that includes important aspects of the TME spanning subcellular-, cellular- and tissue-level scales. The mathematical model is...
Computer simulation of knee arthrometry to study the effects of partial ACL injury and tibiofemoral contact, Article 30th Annual International Conference of the IEEE Engineering in Medicine and Biology Society, EMBS'08, Vancouver, BC, 20 August 2008 through 25 August 2008 ; 2008 , Pages 895-898 ; 9781424418152 (ISBN) ; Farahmand, F ; Rezaeian, T ; Parnianpour, M ; Sharif University of Technology
IEEE Computer Society 2008
We simulated the knee arthrometry test to obtain a deeper understanding of the joint's stability behavior and interpret the arthrometric results more effectively. A 2D sagittal plane finite element model of the lower limb in the standard configuration of knee arthrometry was developed using ANSYS APDL. A detailed model of the knee joint was considered including the femoral articulating contour represented by an ellipse, the tibial plateau represented by a circular arc, and four major knee ligaments and their individual bundles represented by linear and nonlinear tensile springs. A deformable layer of articular cartilage was also considered over the tibial plateau to simulate the bones...
A rigid body spring model to investigate the lateral shift-Restraining force behavior of the patellar, Article 29th Annual International Conference of IEEE-EMBS, Engineering in Medicine and Biology Society, EMBC'07, Lyon, 23 August 2007 through 26 August 2007 ; 2007 , Pages 4679-4682 ; 05891019 (ISSN) ; 1424407885 (ISBN); 9781424407880 (ISBN) ; Farahmand, F ; Meghdari, A ; Sharif University of Technology
Patellar lateral stability was studied using a 2D transverse plane model with deformable articular surfaces. Quadriceps muscles and patellar tendon were considered as strings with predefined forces and lateral and medial retinaculum as tensile springs. Deformation behavior of articular cartilage was modeled by a set of compression springs perpendicular to articular surfaces, based on rigid body spring model method (RBSM). Patellar lateral stability was investigated using restraining force method (the external force required to cause up to 10 mm lateral displacement on patella). The results were in good agreement with experimental reports for normal joint, vastus lateralis and vastus medialis...
Anxiety and cognitive load affect upper limb motor control in Parkinson's disease during medication phases, Article Annals of the New York Academy of Sciences ; Volume 1494, Issue 1 , 2021 , Pages 44-58 ; 00778923 (ISSN) ; Mehdizadeh, H ; Azad, A ; Mehdizadeh, M ; Reyhanian, E ; Saberi, Z. S ; Meimandi, M ; Soltanzadeh, A ; Roohi Azizi, M ; Vasaghi Gharamaleki, B ; Parnianpour, M ; Khalaf, K ; Taghizadeh, G ; Sharif University of Technology
John Wiley and Sons Inc 2021
Anxiety is among the most debilitating nonmotor symptoms of Parkinson's disease (PD). This study aimed to determine how PD patients with low and high levels of anxiety (LA-PD and HA-PD, respectively) compare with age- and sex-matched controls at the level of motor control of reach-to-grasp movements during single- and dual-task conditions with varying complexity. Reach-to-grasp movement kinematics were assessed in 20 LA-PD, 20 HA-PD, and 20 sex- and age-matched healthy controls under single- as well as easy and difficult dual-task conditions. Assessment of PD patients was performed during both the on- and off-drug phases. The results obtained during dual-task conditions reveal deficits in...
Modeling the Parkinson's tremor and its treatments, Article Journal of Theoretical Biology ; Volume 236, Issue 3 , 2005 , Pages 311-322 ; 00225193 (ISSN) ; Sarbaz, Y ; Gharibzadeh, S ; Sharif University of Technology
In this paper, we discuss modeling issues of the Parkinson's tremor. Through the work we have employed physiological structure as well as functioning of the parts in brain that are involved in the disease. To obtain more practical similarity, random behaviors of the connection paths are also considered. Medication or treatment of the disease both by drug prescription and electrical signal stimulation are modeled based on the same model introduced for the disease itself. Two new medication strategies are proposed based on the model to reduce the side effects caused by the present drug prescription. © 2005 Elsevier Ltd. All rights reserved
Molecular dynamics simulation and MM-PBSA calculations of sickle cell hemoglobin in dimer form with Val, Trp, or Phe at the lateral contact, Article Journal of Physical Organic Chemistry ; Volume 23, Issue 9 , March , 2010 , Pages 866-877 ; 08943230 (ISSN) ; Akbarzadeh, H ; Parsafar, G. A ; Sharif University of Technology
As the delay time and hence nuclei formation play a crucial role in the pathophysiology of sickle cell disease, MD simulation and molecular mechanics-Poisson-Boltzmann surface area (MM-PBSA) calculations have been performed on three systems of hemoglobin; namely dimer of hemoglobin with valine (Hb S), tryptophan (Hbβ6W), and phenylalanine (Hbβ6F) at β6 position. The structural changes due to these aromatic substitutions are investigated. It is shown that β subunits have significant impact on the differences between a dimer and other crystal structures. Transition from a dimer to polymer for Hb S system affects the donor molecule more than that of the acceptor. In the case of donor and...
Goal equivalent manifold analysis of task performance in non-specific LBP and healthy subjects during repetitive trunk movement; effect of load, velocity, symmetry, Article Human Movement Science ; Volume 51 , 2017 , Pages 72-81 ; 01679457 (ISSN) ; Sanjari, M. A ; Mokhtarinia, H. R ; Jamshidi, A. A ; Maroufi, N ; Parnianpour, M ; Sharif University of Technology
Motor abundance allows reliability of motor performance despite its variability. The nature of this variability provides important information on the flexibility of control strategies. This feature of control may be affected by low back pain (LPB) and trunk flexion/extension conditions. Goal equivalent manifold (GEM) analysis was used to quantify the ability to exploit motor abundance during repeated trunk flexion/extension in healthy individuals and people with chronic non-specific LBP (CNSLBP). Kinematic data were collected from 22 healthy volunteers and 22 CNSLBP patients during metronomically timed, repeated trunk flexion/extension in three conditions of symmetry, velocity, and loading;...
Role and significance of trunk and upper extremity muscles in walker-assisted paraplegic gait: a case study, Article Topics in Spinal Cord Injury Rehabilitation ; Volume 24, Issue 1 , 2018 , Pages 18-27 ; 10820744 (ISSN) ; Farahmand, F ; Arazpour, M ; Zohoor, H ; Sharif University of Technology
Thomas Land Publishers Inc 2018
Background and Purpose: Understanding the role and significance of trunk and upper extremity muscles in paraplegic gait can help in designing more effective assistive devices for these patients and also provides valuable information for improving muscle strengthening programs. Methods: In a patient with a spinal cord injury (SCI) who could walk independently (rating scale of ambulatory capacity, 9) with the aid of bilateral ankle-foot orthosis and a walker, the kinematics, kinetics and electromyographic (EMG) activities of 16 muscles from the trunk and upper and lower extremities were recorded during gait. The onset, cessation, and duration of the EMG signal were associated with the 4 phases...
Mechanical characterization of the ligaments in subject-specific models of the patellofemoral joint using in vivo laxity tests, Article Knee ; Volume 26, Issue 6 , 2019 , Pages 1220-1233 ; 09680160 (ISSN) ; Farahmand, F ; Arjmand, N ; Sharif University of Technology
Elsevier B.V 2019
Background: The purpose of this study was to propose a methodology for mechanical characterization of the ligaments in subject-specific models of the patellofemoral joint (PFJ) of living individuals. Method: PFJ laxity tests were performed on a healthy volunteer using a specially designed loading apparatus under biplane fluoroscopy. A three-dimensional (3D) parametric model of the PFJ was developed in the framework of the rigid body spring model using the geometrical data acquired from the subject's computed tomography and magnetic resonance images. The stiffness and pre-strains of the medial and lateral PFJ ligaments were characterized using a two-step optimization procedure which minimized...
Lower extremity kinematic analysis in male athletes with unilateral anterior cruciate reconstruction in a jump-landing task and its association with return to sport criteria, Article BMC Musculoskeletal Disorders ; Volume 20, Issue 1 , 2019 ; 14712474 (ISSN) ; Esfandiarpour, F ; Mehdizadeh, S ; Yousefzadeh, N. K ; Parnianpour, M ; Sharif University of Technology
BioMed Central Ltd 2019
Background: Return to sport (RTS) criteria are widely being used to identify anterior cruciate ligament reconstructed (ACLR) athletes ready to return to sportive activity and reduce risk of ACL re-injury. However, studies show a high rate of ACL re-injury in athletes who passed RTS criteria. This indicates that the current RTS criteria might not be sufficient to determine return to sport time in ACLR athletes. Previous studies have reported a close association between altered lower limb kinematics and ACL re-injury. However, it is not clear how lower extremity kinematics differs between ACLR athletes who passed the RTS-criteria and who failed. This study compared lower extremity kinematics...
The metabolomics signature associated with responsiveness to steroid therapy in focal segmental glomerulosclerosis: A pilot study, Article Revista de Investigacion Clinica ; Volume 71, Issue 2 , 2019 , Pages 106-115 ; 00348376 (ISSN) ; Kalantari, S ; Nafar, M ; Boroumandnia, N ; Sharif University of Technology
Instituto Nacional de la Nutricion Salvador Zubiran 2019
Background: Focal segmental glomerulosclerosis (FSGS) is considered one of the most severe glomerular diseases and around 80% of cases are resistant to steroid treatment. Since a large proportion of steroid-resistant (SR) FSGS patients progress to end-stage renal disease, other therapeutic strategies may benefit this population. However, identification of non-invasive biomarkers to predict this high-risk population is needed. Objective: We aimed to identify the biomarker candidates to distinguish SR from steroid-sensitive (SS) patients using metabolomics approach and to identify the possible molecular mechanism of resistance. Methods: Urine was collected from biopsy-proven FSGS patients...
Gut-on-a-chip: Current progress and future opportunities, Article Biomaterials ; Volume 255 , 2020 ; Nasiri, R ; Barros, N. R. D ; Tebon, P ; Thakor, J ; Goudie, M ; Shamloo, A ; Martin, M. G ; Khademhosseni, A ; Sharif University of Technology
Elsevier Ltd 2020
Organ-on-a-chip technology tries to mimic the complexity of native tissues in vitro. Important progress has recently been made in using this technology to study the gut with and without microbiota. These in vitro models can serve as an alternative to animal models for studying physiology, pathology, and pharmacology. While these models have greater physiological relevance than two-dimensional (2D) cell systems in vitro, endocrine and immunological functions in gut-on-a-chip models are still poorly represented. Furthermore, the construction of complex models, in which different cell types and structures interact, remains a challenge. Generally, gut-on-a-chip models have the potential to...
Adaptive neuro-fuzzy inference system for classification of ACL-ruptured knees using arthrometric data, Article Annals of Biomedical Engineering ; Volume 36, Issue 9 , 9 July , 2008 , Pages 1449-1457 ; 00906964 (ISSN) ; Farahmand, F ; Arabalibeik, H ; Parnianpour, M ; Sharif University of Technology
A new approach, based on Adaptive-Network-based Fuzzy Inference System (ANFIS), is presented for the classification of arthrometric data of normal/ACL-ruptured knees, considering the insufficiency of existing criteria. An ANFIS classifier was developed and tested on a total of 4800 arthrometric data points collected from 40 normal and 40 injured subjects. The system consisted of 5 layers and 8 rules, based on the results of subtractive data clustering, and trained using the hybrid algorithm method. The performance of the system was evaluated in four runs, in the framework of a 4-fold cross validation algorithm. The results indicated a definite correct diagnosis for typical injured and normal...
The effects of trochlear groove geometry on patellofemoral joint stability - A computer model study, Article Proceedings of the Institution of Mechanical Engineers, Part H: Journal of Engineering in Medicine ; Volume 222, Issue 1 , 2008 , Pages 75-88 ; 09544119 (ISSN) ; Farahmand, F ; Meghdari, A ; Sharif University of Technology
The effect of the variation in the femoral groove geometry on patellofemoral joint stability was studied using a two dimensional transverse plane model with deformable articular surfaces. The femoral and patellar bony structures were modelled as rigid bodies with their profiles expressed by splines. The articular cartilage was discretized into compression springs, distributed along the femoral and patellar profiles, based on the rigid-body spring model. The medial and lateral retinacula were modelled as linear tensile springs, and the quadriceps muscles and patellar tendon as strings with known tension. The anatomical data were obtained from the transverse plane magnetic resonance images of...
Abnormal expression of NF-κB-related transcripts in blood of patients with inflammatory peripheral nerve disorders, Article Metabolic Brain Disease ; Volume 36, Issue 8 , 2021 , Pages 2369-2376 ; 08857490 (ISSN) ; Ghafouri Fard, S ; Badrlou, E ; Omrani, D ; Nazer, N ; Sayad, A ; Taheri, M ; Sharif University of Technology
The NF-κB family includes some transcription factors which have important functions in the regulation of immune responses, therefore participating in the pathophysiology of inflammatory conditions such as peripheral neuropathies. We have quantified expression of a number of NF-κB-related transcripts in patients with Guillain-Barré syndrome (GBS) or chronic inflammatory demyelinating polyneuropathy (CIDP) versus healthy subjects. These transcripts have been previously shown to be functionally related with this family of transcription factors. Expressions of ATG5, DICER-AS1, PACER, DILC, NKILA and ADINR have been increased in both CIDP and GBS patients compared with controls. However,...
A novel distributed model of the heart under normal and congestive heart failure conditions, Article Proceedings of the Institution of Mechanical Engineers, Part H: Journal of Engineering in Medicine ; Volume 227, Issue 4 , 2013 , Pages 362-372 ; 09544119 (ISSN) ; Jahed, M ; Sharif University of Technology
Conventional models of cardiovascular system frequently lack required detail and focus primarily on the overall relationship between pressure, flow and volume. This study proposes a localized and regional model of the cardiovascular system. It utilizes noninvasive blood flow and pressure seed data and temporal cardiac muscle regional activity to predict the operation of the heart under normal and congestive heart failure conditions. The analysis considers specific regions of the heart, namely, base, mid and apex of left ventricle. The proposed method of parameter estimation for hydraulic electric analogy model is recursive least squares algorithm. Based on simulation results and comparison...
Studying the effect of kinematical pattern on the mechanical performance of paraplegic gait with reciprocating orthosis, Article Proceedings of the Institution of Mechanical Engineers, Part H: Journal of Engineering in Medicine ; Volume 226, Issue 8 , 2012 , Pages 600-611 ; 09544119 (ISSN) ; Farahmand, F ; Salarieh, H ; Sharif University of Technology
Paraplegic users of mechanical walking orthoses, e.g. advanced reciprocating gait orthosis (ARGO), often face high energy expenditure and extreme upper body loading during locomotion. We studied the effect of kinematical pattern on the mechanical performance of paraplegic locomotion, in search for an improved gait pattern that leads to lower muscular efforts. A three-dimensional, four segment, six-degrees-of-freedom skeletal model of the advanced reciprocating gait orthosis-assisted paraplegic locomotion was developed based on the data acquired from an experimental study on a single subject. The effect of muscles was represented by ideal joint torque generators. A response surface analysis...