Publications by authors named "Mehrdad Farahani"

9 Publications

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Investigation of sarcoidosis patients during COVID-19 pandemic.

Sarcoidosis Vasc Diffuse Lung Dis 2020 16;37(4):e2020015. Epub 2020 Dec 16.

Chronic Respiratory Diseases Research Center, National Research Institute of Tuberculosis and Lung Diseases (NRITLD), Shahid Beheshti University of Medical Sciences, Tehran, Iran.

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http://dx.doi.org/10.36141/svdld.v37i4.9588DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7883509PMC
December 2020

The incidence of mTOR marker in tracheal adenoid cystic carcinoma by immunohistochemical staining.

Adv Respir Med 2020 ;88(4):305-312

Chronic Respiratory Diseases Research Center, National Research Institute of Tuberculosis and Lung Diseases, Shahid Beheshti University of Medical Sciences, Tehran, Iran.

Introduction: There is an association between the activation of mammalian target of rapamycin (mTOR) signaling and aggressive tumor growth in multiple forms of cancer,including adenoid cystic carcinoma (ACC). ACCs are uncommon yet a malignant form of neoplasms that arises within the secretory glands. Therefore, the aim of this study was to investigate the increase of mTOR in the ACC tumors in order to survey the possibility of treating these tumors with mTOR inhibitors.

Material And Methods: Samples from known cases of the lung and tracheal ACC were retrievedfrom the archives of the pa-thology department of Masih Daneshvari hospital, and immunohistochemical (IHC) staining for mTOR was performed on them. After preparation of the blocks with specific antibodies, tumor cells with cytoplasmic and/or nuclear expression of mTOR were considered as positive cells by applying a specific scoring method introduced in this study.

Results: The paraffin blocks of 26 patients were surveyed and the IHC marker of mTOR was positive in the tumors of 10 patients (38.5%). Out of 10 mTOR positive cases, 5 were females and 5 were males. The primary site of the surveyed tumors was the trachea and bronchus in 12 cases (46%), salivary glands in 7 individuals (27%), and lung tissue in 7 cases (27%), and there was no significant correlation between the primary site of the ACC tumors and the existence of the mTOR markers in them (P = 0.67). From all cases, 13 patients (50%) had cribriform and tubular cells without solid components, 9 cases (34.6%) had cribriform and tubular with less than 30% of solid components, and 4 cases (15.4%) had cribriform and tubular cells with more than 30% of solid com-ponents. There was no significant difference between the morphologies and the existence of mTOR markers in them (P = 0.741).

Conclusions: As the incidence of mTOR markers is seen in patients with tracheal ACC, evaluation and scoring of mTOR in these persons can be helpful as further studies can distinguish the use of it in the treatment of the disease. .
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http://dx.doi.org/10.5603/ARM.a2020.0120DOI Listing
January 2020

Identification of Sonographic Features for Predicting Benign Versus Malignant Mediastinal or Hilar Lymph Nodes Using Endobronchial Ultrasound.

Oman Med J 2020 Mar 30;35(2):e112. Epub 2020 Apr 30.

Tracheal Diseases Research Center, National Research Institute of Tuberculosis and Lung Diseases, Shahid Beheshti University of Medical Sciences, Tehran, Iran.

Objectives: In countries with a high prevalence of tuberculosis, such as Iran, the differentiation of malignant from non-malignant tumors is crucial. We attempted to find a reliable model in determining malignant nodes by investigating the sonographic characteristics of lymph nodes (LNs).

Methods: In this prospective study, the morphologic characteristics of LNs, including size, shape, vascular pattern, echogenicity, margin, coagulation necrosis sign, calcification, and central hilar structure, which had been obtained during endobronchial ultrasound-guided transbronchial needle aspiration, were compared with the final pathology results.

Results: We examined 253 LNs from 93 patients. Round shape, non-hilar vascular pattern, heterogeneous echogenicity, hyperechogenicity, distinct margin, and the existence of necrosis signs were significantly higher in malignant nodes. On the other hand, the existence of calcification, as well as the presence of central hilar structure, were highly suggestive of benign nodes ( < 0.050). Multivariate logistic regression revealed that size > 1 cm, heterogeneous echogenicity, hyperechogenicity, the existence of necrosis signs, and the lack of central hilar structure are independent predictive factors for malignancy. The accuracy of each of the aforementioned characteristics are 42.3%, 71.5%, 71.9%, 73.5%, and 65.6%, respectively. Of 74 malignant LNs, 100% had at least one of these independent factors.

Conclusions: The morphological features of LNs based on endobronchial ultrasound-guided transbronchial needle aspiration can play a role in predicting malignancy.
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http://dx.doi.org/10.5001/omj.2020.30DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7199125PMC
March 2020

The utility of elastography during EBUS-TBNA in a population with a high prevalence of anthracosis.

Clin Respir J 2020 May 19;14(5):488-494. Epub 2020 Feb 19.

Tracheal Diseases Research Center, National Research Institute of Tuberculosis and Lung Diseases (NRITLD), Shahid Beheshti University of Medical Sciences, Tehran, Iran.

Background: Ultrasound elastography, is a pioneer sonographic modality that is conducted during endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) in order to increase the accuracy of sampling location. The current study aims to evaluate the usefulness of elastography during EBUS-TBNA in a population with a high prevalence of anthracosis.

Methods: This prospective single-blinded study was performed on 69 lymph nodes (LNs) of patients with mediastinal lymphadenopathy undergoing EBUS-TBNA and EBUS-elastography from October 2017 to July 2018. The stiffness level of the tissue was translated into a color to demonstrate the hardness of tissue. Blue and total areas of each section were measured to calculate the hardness of each LN.

Results: Sixty-nine LNs were evaluated by elastography. Twenty percent of LNs were malignant. There was a statistical difference between malignant and non-malignant nodes based on color dominancy (P = 0.032). However, with the exclusion of anthracosis nodes from the analysis, the difference was more significant (P < 0.001). Moreover, when the blue dominancy was used as the predictor of malignancy or anthracosis, the results showed a significant correlation (P < 001).

Conclusion: The usefulness of elastography in selecting the hardest area of tissue that is appropriate for diagnosing diseases has been proven previously. Since in countries with a high prevalence of anthracosis, blue color achieved using elastography predicts either malignancy or anthracosis so, cases with blue dominancy of LNs in elastography and the white color in the EBUS-TBNA indicate anthracosis-caused calcification should be reconsidered.
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http://dx.doi.org/10.1111/crj.13159DOI Listing
May 2020

Amniotic membrane and its epithelial and mesenchymal stem cells as an appropriate source for skin tissue engineering and regenerative medicine.

Artif Cells Nanomed Biotechnol 2018 24;46(sup2):431-440. Epub 2018 Apr 24.

a Department of Pharmacology, School of Medicine , Shahid Beheshti University of Medical Sciences , Tehran , Iran.

One of the main goals of tissue engineering and regenerative medicine is to develop skin substitutes for treating deep dermal and full thickness wounds. In this regard, both scaffold and cell source have a fundamental role to achieve exactly the same histological and physiological analog of skin. Amnion epithelial and mesenchymal cells possess the characteristics of pluripotent stem cells which have the capability to differentiate into all three germ layers and can be obtained without any ethical concern. Amniotic cells also produce different growth factors, angio-modulatory cytokines, anti-bacterial peptides and a wide range of anti-inflammatory agents which eventually cause acceleration in wound healing. In addition, amniotic membrane matrix exhibits characteristics of an ideal scaffold and skin substitute through various types of extracellular proteins such as collagens, laminins and fibronectins which serve as an anchor for cell attachment and proliferation, a bed for cell delivery and a reservoir of drugs and growth factors involved in wound healing process. Recently, isolation of amniotic cells exosomes, surface modification and cross-linking approaches, construction of amnion based nanocomposites and impregnation of amnion with nanoparticles, construction of amnion hydrogel and micronizing process promoted its properties for tissue engineering. In this manuscript, the recent progress was reviewed which approve that amnion-derived cells and matrix have potential to be involved in skin substitutes; an enriched cell containing scaffold which has a great capability to be translated into the clinic.
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http://dx.doi.org/10.1080/21691401.2018.1458730DOI Listing
June 2019

Experimental validation of a three-dimensional reduced-order continuum model of phonation.

J Acoust Soc Am 2016 08;140(2):EL172

Department of Head and Neck Surgery, University of California, Los Angeles, 31-24 Rehab Center, 1000 Veteran Avenue, Los Angeles, California 90095, USA

Due to the complex nature of the phonation process, a one-dimensional (1D) glottal flow description is often used in current phonation models. Although widely used in voice research, these 1D flow-based phonation models have not been rigorously validated against experiments. In this study, a 1D glottal flow model is coupled with a three-dimensional nonlinear continuum model of the vocal fold and its predictions are compared to physical model experiments. The results show that the 1D flow-based model is able to predict the phonation threshold pressure and onset frequency within reasonable accuracy and to reproduce major vibratory features observed in the experiments.
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http://dx.doi.org/10.1121/1.4959965DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5384606PMC
August 2016

A computational study of the effect of intraglottal vortex-induced negative pressure on vocal fold vibration.

J Acoust Soc Am 2014 Nov;136(5):EL369-75

Department of Head and Neck Surgery, School of Medicine, University of California Los Angeles, 31-24 Rehab Center, 1000 Veteran Avenue, Los Angeles, California 90095

Recent studies reported the formation of intraglottal vortices for medium and high subglottal pressures in excised-larynx experiments, and hypothesized that the suction force created by these vortices might affect vocal fold vibration. However, high subglottal pressures often lead to large vocal fold elastic recoil forces, and it is unclear if the vortex-induced suction force is large enough compared with the elastic recoil force to have noticeable effects on vocal fold vibration. In this study, the validity of this hypothesis was examined using a computational model. The results suggest that intraglottal vortices might only have small effects on vocal fold vibration.
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http://dx.doi.org/10.1121/1.4898743DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4215697PMC
November 2014

A numerical and experimental investigation of the effect of false vocal fold geometry on glottal flow.

J Biomech Eng 2013 Dec;135(12):121006

The false vocal folds are hypothesized to affect the laryngeal flow during phonation. This hypothesis is tested both computationally and experimentally using rigid models of the human larynges. The computations are performed using an incompressible Navier-Stokes solver with a second order, sharp, immersed-boundary formulation, while the experiments are carried out in a wind tunnel with physiologic speeds and dimensions. The computational flow structures are compared with available glottal flow visualizations and are employed to study the vortex dynamics of the glottal flow. Furthermore, pressure data are collected on the surface of the laryngeal models experimentally and computationally. The investigation focuses on three geometric features: the size of the false vocal fold gap; the height between the true and false vocal folds; and the width of the laryngeal ventricle. It is shown that the false vocal fold gap has a significant effect on glottal flow aerodynamics, whereas the second and the third geometric parameters are of lesser importance. The link between pressure distribution on the surface of the larynx and false vocal fold geometry is discussed in the context of vortex evolution in the supraglottal region. It was found that the formation of the starting vortex considerably affects the pressure distribution on the surface of the larynx. The interaction of this vortex structure with false vocal folds creates rebound vortices in the laryngeal ventricle. In the cases of small false vocal fold gap, these rebound vortices are able to reach the true vocal folds during a time period comparable with one cycle of the phonation. Moreover, they can create complex vorticity patterns, which result in significant pressure fluctuations on the surface of the larynx.
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http://dx.doi.org/10.1115/1.4025324DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3815039PMC
December 2013

Lithium inhibits the development of physical dependence to clonidine in mice.

Pharmacol Toxicol 2002 Feb;90(2):89-93

Department of Pharmacology, School of Medicine, Tehran University of Medical Sciences, Iran.

Based on our previous finding that chronic lithium treatment reduced naloxone-precipitated withdrawal syndrome in morphine-treated mice, the effect of chronic lithium treatment was evaluated on the development of dependence to clonidine. Dependence was induced by injection of either morphine (50, 50 and 75 mg/kg, intraperitoneally with 3 hr interval for 3 consecutive days), or clonidine (2 mg/kg/day, intraperitoneally for 10 days). Naloxone (4 mg/kg, intraperitoneally) precipitated withdrawal signs in both morphine- and clonidine-treated mice. Yohimbine (5 mg/kg, intraperitoneally) precipitated withdrawal signs in the clonidine-treated mice, similar to morphine withdrawal signs; but failed to precipitate any significant sign in the morphine-treated mice. Coadministration of lithium was carried out by adding lithium chloride to drinking water (600 mg/l for 20 days; 10 days before the beginning of clonidine administration and 17 days before the administration of morphine to allow the lithium concentration to reach steady-state). The results indicated that chronic lithium administration significantly attenuated the withdrawal signs, precipitated either by yohimbine or naloxone, in clonidine-treated mice. As a conclusion, clonidine withdrawal signs are very similar to opioid withdrawal signs, and lithium is able to prevent the development of physical dependence to clonidine.
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http://dx.doi.org/10.1034/j.1600-0773.2002.900206.xDOI Listing
February 2002