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In vitro assay for osteoinductive activity of different demineralized freeze-dried bone allograft
Vaziri, Shahram,Vahabi, Surena,Torshabi, Maryam,Hematzadeh, Somayeh Korean Academy of Periodontology 2012 Journal of Periodontal & Implant Science Vol.42 No.6
Purpose: Various bone graft materials have been used for periodontal tissue regeneration. Demineralized freeze-dried bone allograft (DFDBA) is a widely used bone substitute. The current widespread use of DFDBA is based on its potential osteoinductive ability. Due to the lack of verifiable data, the purpose of this study was to assess the osteoinductive activity of different DFDBAs in vitro. Methods: Sarcoma osteogenic (SaOS-2) cells (human osteoblast-like cells) were exposed to 8 mg/mL and 16 mg/mL concentrations of three commercial types of DFDBA: Osseo+, AlloOss, and Cenobone. The effect of these materials on cell proliferation was determined using the 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide assay. The osteoinductive ability was evaluated using alizarin red staining, and the results were confirmed by evaluating osteogenic gene expression using reverse transcription polymerase chain reaction (RT-PCR). Results: In the SaOS-2 cells, an 8 mg/mL concentration of Osseo+ and Cenobone significantly increased cell proliferation in 48 hours after exposure (P<0.001); however, in these two bone materials, the proliferation of cells was significantly decreased after 48 hours of exposure with a 16 mg/mL concentration (P<0.001). The alizarin red staining results demonstrated that the 16 mg/mL concentration of all three tested DFDBA induced complete morphologic differentiation and mineralized nodule production of the SaOS-2 cells. The RT-PCR results revealed osteopontin gene expression at a 16 mg/mL concentration of all three test groups, but not at an 8 mg/mL concentration. Conclusions: These commercial types of DFDBA are capable of decreasing proliferation and increasing osteogenic differentiation of the SaOS-2 cell line and have osteoinductive activity in vitro.
Does Ossification of the Posterior Longitudinal Ligament Progress After Fusion?
Sasha Vaziri,Dennis Timothy Lockney,Alexander B. Dru,Adam J. Polifka,W. Christopher Fox,Daniel J. Hoh 대한척추신경외과학회 2019 Neurospine Vol.16 No.3
Starting in the 1960s, ossification of the posterior longitudinal ligament (OPLL) became more commonly diagnosed in Japan. The disease is characterized by a gradual increase in calcification of the posterior longitudinal ligament with the eventual sequelae of cervical canal stenosis and myelopathy. Surgical interventions to relieve stenosis and neurologic symptoms are performed to decompress the cervical canal. Studies demonstrate continued ossification of the OPLL in both nonsurgical and surgically treated patients. In this review, the authors evaluate the epidemiology, pathophysiology, and literature regarding disease progression in OPLL after cervical fusion.
Zika virus as an emerging arbovirus of international public health concern
Samira Vaziri,Siavash Hamzeh Pour,Fateme Akrami-Mohajeri 질병관리본부 2022 Osong Public Health and Research Persptectives Vol.13 No.5
Zika virus (ZIKV) was identified in 1947 in a rhesus monkey during an investigation of the yellow fever virus in the Zika Forest of Uganda; it was also isolated later from humans in Nigeria. The main distribution areas of ZIKV were the African mainland and South-East Asia in the 1980s, Micronesia in 2007, and more recently the Americas in 2014. ZIKV belongs to the Flaviviridae family and Flavivirus genus. ZIKV infection, which is transmitted by Aedes mosquitoes, is an emerging arbovirus disease. The clinical symptoms of ZIKV infection are fever, headache, rashes, arthralgia, and conjunctivitis, which clinically resemble dengue fever syndrome. Sometimes, ZIKV infection has been associated with Guillain-Barré syndrome and microcephaly. At the end of 2015, following an increase in cases of ZIKV infection associated with Guillain-Barré syndrome and microcephaly in newborns in Brazil, the World Health Organization declared a global emergency. Therefore, considering the global distribution and pathogenic nature of this virus, the current study aimed at reviewing the virologic features, transmission patterns, clinical manifestations, diagnosis, treatment, and prevention of ZIKV infection.
In vitro assay for osteoinductive activity of different demineralized freeze-dried bone allograft
Shahram Vaziri,Surena Vahabi,Maryam Torshabi,Somayeh Hematzadeh 대한치주과학회 2012 Journal of Periodontal & Implant Science Vol.42 No.6
Purpose: Various bone graft materials have been used for periodontal tissue regeneration. Demineralized freeze-dried bone allograft (DFDBA) is a widely used bone substitute. The current widespread use of DFDBA is based on its potential osteoinductive ability. Due to the lack of verifiable data, the purpose of this study was to assess the osteoinductive activity of different DFDBAs in vitro. Methods: Sarcoma osteogenic (SaOS-2) cells (human osteoblast-like cells) were exposed to 8 mg/mL and 16 mg/mL concentrations of three commercial types of DFDBA: Osseo+, AlloOss, and Cenobone. The effect of these materials on cell proliferation was determined using the 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide assay. The osteoinductive ability was evaluated using alizarin red staining, and the results were confirmed by evaluating osteogenic gene expression using reverse transcription polymerase chain reaction (RT-PCR). Results: In the SaOS-2 cells, an 8 mg/mL concentration of Osseo+ and Cenobone significantly increased cell proliferation in 48 hours after exposure (P<0.001); however, in these two bone materials, the proliferation of cells was significantly decreased after 48 hours of exposure with a 16 mg/mL concentration (P<0.001). The alizarin red staining results demonstrated that the 16 mg/mL concentration of all three tested DFDBA induced complete morphologic differentiation and mineralized nodule production of the SaOS-2 cells. The RT-PCR results revealed osteopontin gene expression at a 16 mg/mL concentration of all three test groups, but not at an 8 mg/mL concentration. Conclusions: These commercial types of DFDBA are capable of decreasing proliferation and increasing osteogenic differentiation of the SaOS-2 cell line and have osteoinductive activity in vitro.
The Wall–Frame Interaction Effect in Corrugated Steel Plate Shear Walls Systems
Ehsan Vaziri,Mohammad Gholami,Mojtaba Gorji Azandariani 한국강구조학회 2021 International Journal of Steel Structures Vol.21 No.5
The corrugated steel plate shear wall (CSPSW) system is a lateral force-resisting system, about which many studies have been carried out in recent years. In the present study, the behavior of this system is investigated by pushover analysis. For this purpose, twenty CSPSWs structures are designed with width-to-height ratio (L/H) of 2.5, 2, 1.4, and 0.85, and the number of fl oors 1, 2, 4, 6, and 10 were designed and analyzed using the ABAQUS fi nite element software package. The results of this study show that the initial stiff ness of CSPSWs is high and reaches its ultimate capacity at a thrust ratio of 0.1%; on the other hand, after the buckling in the infi ll plate, the stiff ness and base shear of the plate shear wall (PSW) signifi cantly decreases. Also, the results show that the infi ll plate tolerates a higher percentage of shear force before the buckling of the plate, but after buckling, the frame tolerates a higher percentage of the shear force. In multi-story structures, the boundary frame with shear performance in the lower fl oors has a more eff ective role in bearing shear force. Moreover, in the present study, an equation is presented for calculating the tension fi eld inclination angle. According to the equation, the tension fi eld inclination angle depends only on the PSW aspect ratio. Finally, a method is presented for estimating the uniform force–displacement curve of the single- and multi-story CSPSW systems. This method is obtained based on the corrugated plate-frame interaction (PFI) and was confi rmed with the force–displacement curve of experimental specimens and numerical models.