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Riazi-Esfahani H, Asadi Khameneh E, Ghassemi F, Mehrabi Bahar M, Torkashvand A, Mahmoudi A, Husein Ahmed A, Faghihi S, Rahimi M, Akbarzadeh A, Faghihi H, Khalili Pour E. Pachychoroid neovasculopathy versus macular neovascularization in age-related macular degeneration with and without shallow irregular pigment epithelial detachment. Sci Rep 2023; 13:19513. [PMID: 37945766 PMCID: PMC10636113 DOI: 10.1038/s41598-023-46891-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2023] [Accepted: 11/06/2023] [Indexed: 11/12/2023] Open
Abstract
To compare the choroidal neovascular features of individuals with pachychoroid neovasculopathy (PNV) and neovascular age-related macular degeneration (nAMD) with and without shallow irregular pigment epithelial detachment (SIPED). Using optical coherence tomography angiography, the choroidal neovascular complexes of 27 patients with PNV, 34 patients with nAMD and SIPED, and 15 patients with nAMD without SIPED were analyzed with FIJI and AngioTool software. PNV compared to nAMD with SIPED had a greater vessel percentage area (P = 0.034), junction density (P = 0.045), average vessel length (P < 0.001), and fractal dimension (P < 0.001). PNV, compared to nAMD without SIPED, had a greater total vessel length (P = 0.002), total number of junctions (P < 0.001), junction density (P = 0.034), and fractal dimension (P = 0.005). nAMD with SIPED, compared to nAMD without SIPED, had greater vessel area, total number of junctions, total vessel length, and average vessel length (all P values < 0.001). Patients with nAMD plus SIPED and individuals with nAMD without SIPED have similar fractal dimension values (P = 0.703). Biomarkers of choroidal neovascular complexity, such as fractal dimension, can be used to differentiate PNV from nAMD with or without SIPED.
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Affiliation(s)
| | - Esmaeil Asadi Khameneh
- Farabi Eye Hospital, Tehran University of Medical Sciences, Tehran, Iran.
- Eye Research Center, Farabi Eye Hospital, Qazvin Sq, Tehran, Iran.
| | - Fariba Ghassemi
- Farabi Eye Hospital, Tehran University of Medical Sciences, Tehran, Iran
| | | | | | | | - Ahmed Husein Ahmed
- Farabi Eye Hospital, Tehran University of Medical Sciences, Tehran, Iran
| | - Shahin Faghihi
- Farabi Eye Hospital, Tehran University of Medical Sciences, Tehran, Iran
| | - Masoud Rahimi
- Farabi Eye Hospital, Tehran University of Medical Sciences, Tehran, Iran
| | - Ali Akbarzadeh
- Farabi Eye Hospital, Tehran University of Medical Sciences, Tehran, Iran
| | - Hooshang Faghihi
- Farabi Eye Hospital, Tehran University of Medical Sciences, Tehran, Iran
| | - Elias Khalili Pour
- Farabi Eye Hospital, Tehran University of Medical Sciences, Tehran, Iran
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Faghihi H, Inanloo B, Mirzaee A, Fadakar K, Mirshahi A, Ebrahimiadib N, Ghassemi F, Bazvand F, Amini A, Mirghorbani M, Faghihi S, Khalili Pour E, Riazi-Esfahani H. Evaluation of the additive effect of interferon α 2b with monthly intravitreal injection of bevacizumab in refractory diabetic macular edema. Int J Retina Vitreous 2022; 8:74. [PMID: 36224669 PMCID: PMC9558405 DOI: 10.1186/s40942-022-00424-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2022] [Accepted: 09/21/2022] [Indexed: 11/13/2022] Open
Abstract
Background To evaluate the additive effect of topical or sub-tenon injection of interferon (IFN)-α 2b in the treatment of refractory diabetic macular edema. Methods In this prospective study patients with center-involved DME who were unresponsive to 3 monthly consecutive IVB injections were recruited. Patients were divided into three groups: group1, received IFN- α 2b topical drop at a dose of 1mIU/ml four times a day for 3 months. Group 2, received a single sub-tenon injection of 1mIU/ml IFN- α 2b at the enrollment. Group 3 received artificial tears four times a day for 3 months (control group). All groups received three consecutive monthly IVB injections and were evaluated monthly up to 1 month following the last IVB injection. Results In this study, 59 eyes of 35 patients with refractory DME were assessed. The final follow-up showed that although CMT decreased in all groups, only patients in Group 2 had statistically significant lower CMT compared to their baseline values (change in CMT: − 117 ± 213 µm; p-value = 0.025). Comparison of CMT changes between three groups showed no statistically significant difference, although it was higher in group 2 (change in CMT: − 117 ± 213 µm (Group2) vs. − 49 ± 173 (Group 1) vs. − 36 ± 86 (Group 3); p-value = 0.085). Considering eyes with baseline CMT > 400 µm, sub-tenon injection of IFN α2b led to a significant reduction of CMT at the first month and final follow-up visit (CMT change: − 166 ± 210, − 145 ± 231 µm; p-value = 0.018 and 0.035, respectively). In this subgroup, eyes in Group 2 had lower CMT at the first month following treatment in comparison with the control group (CMT: 444 ± 123 µm vs. 544 ± 96 µm, p-value = 0.042). Alterations of CDVA were not statistically significant among groups, although patients in Group 1 had a significant improvement in vision at second and last follow up (CDVA change: − 0.23 ± 0.39, − 0.20 ± 0.43 logMAR; p-value = 0.030 and 0.010, respectively). Conclusions In short term, Sub-tenon injection of IFN might have an additive anatomical effect in eyes with refractory DME. Validation of this observation requires further prospective controlled studies.
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Affiliation(s)
- Hooshang Faghihi
- Retina Service, Farabi Eye Hospital, Tehran University Of Medical Sciences, Qazvin Square, South Karegar Street, Tehran, 1336616351, Iran
| | - Bahman Inanloo
- Retina Service, Farabi Eye Hospital, Tehran University Of Medical Sciences, Qazvin Square, South Karegar Street, Tehran, 1336616351, Iran
| | - Arash Mirzaee
- Retina Service, Farabi Eye Hospital, Tehran University Of Medical Sciences, Qazvin Square, South Karegar Street, Tehran, 1336616351, Iran
| | - Kaveh Fadakar
- Retina Service, Farabi Eye Hospital, Tehran University Of Medical Sciences, Qazvin Square, South Karegar Street, Tehran, 1336616351, Iran
| | - Ahmad Mirshahi
- Retina Service, Farabi Eye Hospital, Tehran University Of Medical Sciences, Qazvin Square, South Karegar Street, Tehran, 1336616351, Iran
| | - Nazanin Ebrahimiadib
- Retina Service, Farabi Eye Hospital, Tehran University Of Medical Sciences, Qazvin Square, South Karegar Street, Tehran, 1336616351, Iran
| | - Fariba Ghassemi
- Retina Service, Farabi Eye Hospital, Tehran University Of Medical Sciences, Qazvin Square, South Karegar Street, Tehran, 1336616351, Iran
| | - Fatemeh Bazvand
- Retina Service, Farabi Eye Hospital, Tehran University Of Medical Sciences, Qazvin Square, South Karegar Street, Tehran, 1336616351, Iran
| | - Abdulrahman Amini
- Retina Service, Farabi Eye Hospital, Tehran University Of Medical Sciences, Qazvin Square, South Karegar Street, Tehran, 1336616351, Iran
| | - Masoud Mirghorbani
- Retina Service, Farabi Eye Hospital, Tehran University Of Medical Sciences, Qazvin Square, South Karegar Street, Tehran, 1336616351, Iran
| | - Shahin Faghihi
- Retina Service, Farabi Eye Hospital, Tehran University Of Medical Sciences, Qazvin Square, South Karegar Street, Tehran, 1336616351, Iran
| | - Elias Khalili Pour
- Retina Service, Farabi Eye Hospital, Tehran University Of Medical Sciences, Qazvin Square, South Karegar Street, Tehran, 1336616351, Iran
| | - Hamid Riazi-Esfahani
- Retina Service, Farabi Eye Hospital, Tehran University Of Medical Sciences, Qazvin Square, South Karegar Street, Tehran, 1336616351, Iran.
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Roohipourmoallai R, Faghihi S, Faghihi H, Torkashvand A, Nabavi A, Fooladi MI, Farahani AD, Bazvand F, R Iyer SS, Ebrahimiadib N. Transscleral vs transpupillary diode laser photocoagulation for the treatment of zone II type 1 retinopathy of prematurity: Anatomical and refractive outcomes. Indian J Ophthalmol 2021; 70:189-193. [PMID: 34937237 PMCID: PMC8917555 DOI: 10.4103/ijo.ijo_1125_21] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Abstract
Purpose To compare the anatomical and refractive outcomes of transscleral diode versus transpupillary laser photocoagulation for the treatment of zone II type 1 retinopathy of prematurity (ROP). Methods In this prospective comparative interventional case series, infants with type 1 ROP in zone II were assigned to either transpupillary or transscleral laser based on the surgeons' expertise area. The rate of regression, need for retreatment, and structural and biometric outcomes at month 6 were evaluated and compared between the two treatment groups. Results In total, 209 eyes were enrolled; 145 eyes of 77 infants and 64 eyes of 33 infants and were in transscleral and transpupillary groups, respectively. There was no significant difference in baseline characteristics between the groups. There was no significant difference in retreatment rates (1.6% vs. 3.4%; P = 0.669) and progression to stage 4 (1.6% vs. 2.8%; P = 0.999) between the transpupillary and transscleral groups, respectively. At month 6, the mean spherical equivalent was 0.31 ± 3.57 and 0.44 ± 2.85 diopters, and the axial length was 18.28 ± 6.22 and 18.36 ± 6.87 mm in the transpupillary and transscleral groups, respectively, without a significant difference between groups. There was no significant difference in the rate of myopia (43.8% vs. 33.8%; P = 0.169) and high myopia (4.7% vs. 4.8%; P = 0.965) in transpupillary and transscleral groups at month 6. Conclusion The transpupillary and transscleral laser photocoagulation routes are both effective in the treatment of zone II type 1 ROP and show no significant differences in anatomical or refractive outcomes in relation to the route chosen.
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Affiliation(s)
- Ramak Roohipourmoallai
- Department of Ophthalmology, Morsani College of Medicine, University of South Florida, Tampa, FL, USA
| | - Shahin Faghihi
- Department of Ophthalmology, Tehran University of Medical Sciences, Tehran, Iran
| | - Hooshang Faghihi
- Department of Ophthalmology, Tehran University of Medical Sciences, Tehran, Iran
| | - Ali Torkashvand
- Department of Ophthalmology, Tehran University of Medical Sciences, Tehran, Iran
| | - Amin Nabavi
- Department of Ophthalmology, Guilan University of Medical Sciences, Rasht, Iran
| | - Marjan I Fooladi
- Department of Ophthalmology, Tehran University of Medical Sciences, Tehran, Iran; Department of Ophthalmology, The University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - Afsar D Farahani
- Department of Ophthalmology, Tehran University of Medical Sciences, Tehran, Iran
| | - Fatemeh Bazvand
- Department of Ophthalmology, Tehran University of Medical Sciences, Tehran, Iran
| | - Siva S R Iyer
- Department of Ophthalmology, University of Florida, Gainesville, FL, USA
| | - Nazanin Ebrahimiadib
- Department of Ophthalmology, Tehran University of Medical Sciences, Tehran, Iran
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Faghihi H, Riazi-Esfahani H, Khodabande A, Khalili Pour E, Mirshahi A, Ghassemi F, Mirshahi R, Khojasteh H, Bazvand F, Hashemi A, Tayebi F, Faghihi S, Riazi Esfahani M. Effect of panretinal photocoagulation on macular vasculature using optical coherence tomography angiography. Eur J Ophthalmol 2020; 31:1877-1884. [PMID: 32820946 DOI: 10.1177/1120672120952642] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
BACKGROUND To evaluate the changes of macular vascular density in the superficial capillary (SCP) and the deep capillary plexus (DCP), foveal avascular area (FAZ), choroidal flow, and macular thickness after pan-retinal photocoagulation (PRP). METHODS In this prospective interventional non-comparative case series, patients with very severe nonproliferative (NPDR) and early proliferative diabetic retinopathy (PDR) and no significant macular edema who were candidates for pan-retinal photocoagulation underwent measurement of corrected distance visual acuity (CDVA), optical coherence tomography (OCT), Optical coherence tomography angiography (OCTA) at the baseline, 1, and 6 months following completion of PRP treatment. RESULTS Thirty-nine eyes from 21 patients with diabetes were enrolled. Superficial and deep capillary plexus densities in the foveal and parafoveal area didn't change significantly 1 and 6 months post-PRP (p > 0.1 in all of them). The FAZ area constricted 6 months following PRP (p = 0.075). Based on the calculated circularity index, the FAZ became significantly more circular after 6 months of follow-up (p = 0.047). Although the choroidal flow area increased after PRP this increase wasn't statically significant neither at 1 month nor at 6 months post-PRP (p = 0.31 and 0.23, respectively). CONCLUSION Although OCTA parameters were not significantly affected by PRP at both short-term (1 month) and long-term (6 months) follow-ups, the FAZ area became significantly circular after PRP may be due to redistribution of blood flow in hypoperfused foveal capillary plexus.
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Affiliation(s)
- Hooshang Faghihi
- Eye Research Center, Farabi Eye Hospital, Tehran University of Medical Sciences, Tehran, Iran
| | - Hamid Riazi-Esfahani
- Eye Research Center, Farabi Eye Hospital, Tehran University of Medical Sciences, Tehran, Iran
| | - Alireza Khodabande
- Eye Research Center, Farabi Eye Hospital, Tehran University of Medical Sciences, Tehran, Iran
| | - Elias Khalili Pour
- Eye Research Center, Farabi Eye Hospital, Tehran University of Medical Sciences, Tehran, Iran
| | - Ahmad Mirshahi
- Eye Research Center, Farabi Eye Hospital, Tehran University of Medical Sciences, Tehran, Iran
| | - Fariba Ghassemi
- Eye Research Center, Farabi Eye Hospital, Tehran University of Medical Sciences, Tehran, Iran
| | - Reza Mirshahi
- Eye Research Center, The Five Senses Institute, Iran University of Medical Sciences, Tehran, Iran
| | - Hassan Khojasteh
- Eye Research Center, Farabi Eye Hospital, Tehran University of Medical Sciences, Tehran, Iran
| | - Fatemeh Bazvand
- Eye Research Center, Farabi Eye Hospital, Tehran University of Medical Sciences, Tehran, Iran
| | - Amirhossein Hashemi
- Eye Research Center, Farabi Eye Hospital, Tehran University of Medical Sciences, Tehran, Iran
| | - Fereshteh Tayebi
- Eye Research Center, Farabi Eye Hospital, Tehran University of Medical Sciences, Tehran, Iran
| | - Shahin Faghihi
- Eye Research Center, Farabi Eye Hospital, Tehran University of Medical Sciences, Tehran, Iran
| | - Mohammad Riazi Esfahani
- Department of Ophthalmology, Gavin Herbert Eye Institute, University of California Irvine, Irvine, CA, USA
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Faghihi H, Mohammadzadeh V, Nabavi A, Faghihi S, Kadivar S, Ghassemi F. Oral Mineralocorticoid-Receptor Antagonists: Choroidal Parameters Changes Using OCT in Central Serous Chorioretinopathy. Ophthalmic Surg Lasers Imaging Retina 2019; 50:726-733. [PMID: 31755972 DOI: 10.3928/23258160-20191031-08] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2018] [Accepted: 04/22/2019] [Indexed: 11/20/2022]
Abstract
BACKGROUND AND OBJECTIVE To evaluate the efficacy and safety of oral eplerenone in the treatment of acute and chronic central serous chorioretinopathy (CSCR). PATIENTS AND METHODS Treatment-naïve patients with acute (< 3 months) and chronic (≥ 3 months) CSCR were enrolled in this prospective, nonrandomized, interventional, comparative case series. Patients with acute CSCR were either treated with oral eplerenone (acute case group; n = 16) or observed only (acute control group; n = 8). All chronic patients (chronic group; n = 25) were treated with oral eplerenone. Eplerenone was prescribed 25 mg twice per day for 3 months. Best-corrected visual acuity (BCVA) and optical coherence tomography measures, including subretinal fluid (SRF) height, subfoveal choroidal thickness (CT), central CT, central choroidal volume (CV), and total CV, were assessed at baseline and 3-month follow-up (FU) visit. RESULTS BCVA improvement and SRF reduction at 3-month FU relative to baseline were observed in all three study groups. SRF was completely resolved in 13 patients (81.2%) in the acute case group, four patients (50%) in the acute control group, and eight patients (32%) in the chronic group. The acute case group showed greater SRF decrease relative to baseline compared to the chronic group (P = .009), but the resolution of SRF between acute cases and an acute control group was not statistically significant (P = .076). Subfoveal CT, central CT, total CV, and central CV were significantly reduced at the 3-month FU compared to baseline in both affected and the fellow eyes in the acute case and chronic groups, whereas no change was observed in either eyes in the acute control group. At 3 months' FU, the mean logMAR visual acuity demonstrated no significant difference among the study groups (P = .08). Eplerenone was well-tolerated, and no serious side effect was detected. CONCLUSIONS Oral eplerenone is a safe and effective treatment option for both acute and chronic CSCR. Resolution of SRF was more significant in acute CSR cases comparative to chronic cases. [Ophthalmic Surg Lasers Imaging Retina. 2019;50:726-733.].
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Tabatabaei SA, Soleimani M, Bohrani B, Banafsheafshan A, Faghihi S, Faghihi H. Multimodal imaging in photic retinopathy. Int J Ophthalmol 2019; 12:523-525. [PMID: 30918826 DOI: 10.18240/ijo.2019.03.27] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2018] [Accepted: 07/05/2018] [Indexed: 01/23/2023] Open
Affiliation(s)
- Seyed Ali Tabatabaei
- Eye Research Center, Farabi Eye Hospital, Tehran University of Medical Sciences, Tehran 1336616351, Iran
| | - Mohammad Soleimani
- Eye Research Center, Farabi Eye Hospital, Tehran University of Medical Sciences, Tehran 1336616351, Iran
| | - Bahram Bohrani
- Eye Research Center, Farabi Eye Hospital, Tehran University of Medical Sciences, Tehran 1336616351, Iran
| | - Ali Banafsheafshan
- Eye Research Center, Farabi Eye Hospital, Tehran University of Medical Sciences, Tehran 1336616351, Iran
| | - Shahin Faghihi
- Eye Research Center, Farabi Eye Hospital, Tehran University of Medical Sciences, Tehran 1336616351, Iran
| | - Houshang Faghihi
- Eye Research Center, Farabi Eye Hospital, Tehran University of Medical Sciences, Tehran 1336616351, Iran
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Karimi A, Navidbakhsh M, Faghihi S. RETRACTED: Fabrication and mechanical characterization of a polyvinyl alcohol sponge for tissue engineering applications. Perfusion 2013; 29:231-7. [DOI: 10.1177/0267659113513823] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The following article has been included in a multiple retraction: Karimi A, Navidbakhsh M and Faghihi S. Fabrication and mechanical characterization of a polyvinyl alcohol sponge for tissue engineering applications. Perfusion 2014;29:231–237, DOI: 10.1177/0267659113513823. In 2015 SAGE became aware of author misconduct concerning the suspected fabrication of identities, as well as the impersonation of legitimate individuals, to manipulate the peer review process across three separate journal publications. SAGE and the journal Editors immediately launched an investigation and have decided to retract the following articles for reasons of author misconduct. Alireza Karimi was the submitting author on 12 of the articles. SAGE regrets the academic record was compromised by manipulation of the peer review process and apologises to readers. OnlineFirst articles (these articles will not be published in an issue) International Journal of Damage Mechanics Karimi A, Navidbakhsh M and Razaghi R. Dynamic finite element simulation of the human head damage mechanics protected by polyvinyl alcohol sponge. Int J Damage Mech, first published on 15 May 2014, DOI: 10.1177/1056789514535945. Journal of Thermoplastic Composite Materials Karimi A, Navidbakhsh M and Haghpanahi M. Constitutive model for numerical analysis of polyvinyl alcohol sponge under different strain rates. J Thermoplast Compos Mater, first published on 15 January 2014, DOI: 10.1177/0892705713520176. Karimi A, Navidbakhsh M, Yousefi H et al. An experimental study on the elastic modulus of gelatin hydrogels using different stress–strain definitions. J Thermoplast Compos Mater, first published on 29 April 2014, DOI: 10.1177/0892705714533377. Elhamian MM, Alizadeh M, Shokrieh MM, et al. An innovative three-dimensional biphasic-laminated composite model for articular cartilage tissue. J Thermoplast Compos Mater, first published on 1 February 2015, DOI: 10.1177/0892705715569821. Perfusion Karimi A, Navidbakhsh M, Yamada H, et al. A comparative study on the quasilinear viscoelastic mechanical properties of the umbilical artery and the umbilical vein. Perfusion, first published on 22 May 2014, DOI: 10.1177/0267659114536761. Tehrani P, Rahmani S, Karimi A, et al. A novel cardiac assist device (AVICENA): a numerical study to compute the generated power. Perfusion, first published on 19 August 2014, DOI: 10.1177/ 0267659114547943. Elhamian SMM, Alizadeh M, Shokrieh MM, et al. The effect of collagen fiber volume fraction on the mechanical properties of articular cartilage by micromechanics models. Perfusion, first published on 20 August 2014, DOI: 10.1177/0267659114547942. Razaghi R, Karimi A, Navidbakhsh M, et al. Determination of the vulnerable plaque in a stenotic human coronary artery – finite element modelling. Perfusion, first published on 28 October 2014, DOI: 10.1177/0267659114557720. Articles published in an issue International Journal of Damage Mechanics Karimi A, Navidbakhsh M, Beigzadeh B, et al. Hyperelastic mechanical behavior of rat brain infected by Plasmodium berghei ANKA – experimental testing and constitutive modelling. Int J Damage Mech 2014;23:857–871, DOI: 10.1177/1056789513514072. Perfusion Karimi A, Navidbakhsh M and Faghihi S. A comparative study on plaque vulnerability using constitutive equations. Perfusion, 2014;29:178–183, DOI: 10.1177/0267659113502835. Abdi M, Karimi A, Navidbakhsh M, et al. Modeling of cerebral aneurysm using equivalent electrical circuit (Lumped Model). Perfusion 2014;29:142–152, DOI: 10.1177/0267659113498617. Karimi A, Navidbakhsh M and Faghihi S. Fabrication and mechanical characterization of a polyvinyl alcohol sponge for tissue engineering applications. Perfusion 2014;29:231–237, DOI: 10.1177/ 0267659113513823. Karimi A, Navidbakhsh M, Yousefi H, et al. Experimental and numerical study on the mechanical behavior of rat brain tissue. Perfusion 2014;29:307–314, DOI: 10.1177/0267659114522088.
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Affiliation(s)
- A Karimi
- Tissue Engineering and Biomaterials Division, National Institute of Genetic Engineering and Biotechnology, Tehran, Iran
- Mechanical Engineering Department, Iran University of Science and Technology, Tehran, Iran
| | - M Navidbakhsh
- Mechanical Engineering Department, Iran University of Science and Technology, Tehran, Iran
| | - S Faghihi
- Tissue Engineering and Biomaterials Division, National Institute of Genetic Engineering and Biotechnology, Tehran, Iran
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Abstract
Atherosclerosis is the most serious and common form of cardiovascular disease in which plaque builds up inside the arteries. Peak plaque stress is considered as the main reason for plaque rupture, which results in heart attack and stroke. In the current research, the finite element method is used to anticipate plaque vulnerability, using human samples. A total of 23 healthy and atherosclerotic human coronary arteries (14 healthy and 9 atherosclerotic) were removed within 5 h postmortem. The samples were mounted on a uniaxial tensile test machine and the obtained mechanical properties were used in finite element models. The peak plaque stresses for the Ogden hyperelastic model were compared to the Mooney-Rivlin and Neo-Hookean outcomes. The results indicated that hypocellular plaque in all three models has the highest stress values compared to the cellular and calcified ones and, as a result, is quite prone to rupture. The calcified plaque type, in contrast, has the lowest stress values and remains stable. The results can be used in plaque vulnerability prediction and have clinical implications for interventions and surgeries such as balloon-angioplasty, cardiopulmonary bypass and stenting.
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Affiliation(s)
- A Karimi
- 1Tissue Engineering and Biomaterials Division, National Institute of Genetic Engineering and Biotechnology, Tehran, Iran
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Abstract
The circle of Willis (CoW) is a key asset in brain performance as it supports adequate blood supply to the brain. The lumped method (electrical equivalent circuits) is a useful model to simulate the process of the human cardiovascular system. In this study, the whole cardiovascular system is modeled, using an equivalent electrical circuit to investigate an aneurysm in an artery. The cerebrovascular system consists of 29 compartments, which includes the CoW. Each vessel is modeled by a resistor, a capacitor and an inductor. Using MATLAB Simulink, the left and right ventricles are modeled by controlled voltage sources and diodes. The effects of the left internal carotid artery aneurysm (Fusiform) on the pressure of the efferent arteries in the circle of Willis are studied. The modeling results are entirely in agreement with the available clinical observations. The results of the present study may have clinical implications for modeling different cardiovascular diseases, such as arterial stiffness and atherosclerosis.
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Affiliation(s)
- M Abdi
- 1Department of Mechanical Engineering, Iran University of Science and Technology, Tehran, Iran
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Danesh-Sani SH, Danesh-Sani SA, Zia R, Faghihi S. Incidence of craniofacial pain of cardiac origin: results from a prospective multicentre study. Aust Dent J 2012; 57:355-8. [DOI: 10.1111/j.1834-7819.2012.01698.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Abstract
Aseptic loosening induced by wear particles from artificial bearing materials is one of the main causes of malfunctioning in total hip replacements. With the increase in young and active patients, complications in revision surgeries and immense health care costs, there is considerable interest in wear-resistant materials that can endure longer in the harsh and corrosive body environment. Here, the tribological behaviour of nanostructured titanium substrates processed by high-pressure torsion (HPT) is investigated and compared with the coarse-grained samples. The high resolution transmission electron microscopy reveals that a nanostructured sample has a grain size of 5-10 nm compared to that of ∼ 10 µm and ∼ 50 µm for untreated and annealed substrates, respectively. Dry and wet wear tests were performed using a linear reciprocating ball-on-flat tribometer. Nanostructured samples show the best dry wear resistance and the lowest wear rate in the electrolyte. There was significantly lower plastic deformation and no change in preferred orientation of nanostructured samples attributable to the wear process. Electrochemical impedance spectroscopy (EIS) shows lower corrosion resistance for nanostructured samples. However, under the action of both wear and corrosion the nanostructured samples show superior performance and that makes them an attractive candidate for applications in which wear and corrosion act simultaneously.
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Affiliation(s)
- S Faghihi
- Tissue Engineering and Biomaterials Division, National Institute of Genetic Engineering and Biotechnology (NIGEB), Room 117, Shahrak-e Pajoohesh, km 15, Tehran-Karaj Highway, Tehran, PO Box 14965/161, Iran.
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Faghihi S, Hoffmann T, Petermann J, Martinez-Salazar J. Decoration of the fold surfaces of polyethylene single crystals with tellurium and tin. Macromolecules 2002. [DOI: 10.1021/ma00035a033] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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