Publications by authors named "Alimohammad Alimohammadi"

5 Publications

  • Page 1 of 1

Investigating the association between chronological age and thyroid cartilage ossification using CT imaging.

Med J Islam Repub Iran 2020 5;34:130. Epub 2020 Oct 5.

Department of Radiology, School of Medicine, AJA University of Medical Sciences, Tehran, Iran.

Thyroid cartilage ossifies through time. In addition to different methods for age estimation, ossified volume can be a valuable index for age estimation. In this study, anthropometric characteristics and ossified volume were measured using CT scan imaging to find potential correlations between measures and age. In this study, 100 thyroid cartilage of Iranian corpses (60 men and 40 women) were studied. Corpses from Kahrizak hall of Tehran Legal Medicine Organization were included in this study. After obtaining required consent from their family, their thyroid cartilage was separated by an expert, and anthropometric properties of the cartilage were recorded. A 64-slice Siemens CT scan machine was used to measure specimen ossified volume and Hounsfield score by 3D reconstruction of images. Pearson's correlation test was used to measure the correlation between thyroid calcified volume and chronological age. Repeated measurement ANOVA test was also used to measure the correlation of the ossified volume and Hounsfield score with different age groups. SPSS version 22 was used for statistical analysis, and significance level was set at than 0.05. All thyroid cartilage measures were higher in men than in women, except for thyroid angle, and the differences were statistically significant. Height of the laminae (R=0.23, p=0.023) and depth of the thyroid notch (R=0.198, p=0.049) were correlated with age. Mean ossified volume (6.1±1.7 cc) and Hounsfield score (308.8±53.5 HU) were directly correlated with age (R=0.205; p=0.040 and R=0.219; p=0.029, respectively), but none of these two radiologic parameters were correlated with age groups (p=0.331 and 0.063, respectively). No specific ossification pattern was obtained from CT images in different age groups. A combination of anthropometric measures such as the height of the laminae and depth of the thyroid notch with CT scan imaging measures such as ossified volume and the Hounsfield score are useful to estimate age with low precision. In addition, thyroid cartilage measures are useful for sex determination.
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October 2020

Conformational change and GTPase activity of human tubulin: A comparative study on Alzheimer's disease and healthy brain.

J Neurochem 2020 09 13;155(2):207-224. Epub 2020 Apr 13.

Department of Neurology and Department of Neurosurgery, Westfälische Wilhelms-Universität Münster, Münster, Germany.

In Alzheimer's disease (AD), the most common form of dementia, microtubules (MTs) play a pivotal role through their highly dynamic structure and instability. They mediate axonal transport that is crucial to synaptic viability. MT assembly, dynamic instability and stabilization are modulated by tau proteins, whose detachment initiates MT disintegration. Albeit extensive research, the role of GTPase activity in molecular mechanism of stability remains controversial. We hypothesized that GTPase activity is altered in AD leading to microtubule dynamic dysfunction and ultimately to neuronal death. In this paper, fresh tubulin was purified by chromatography from normal young adult, normal aged, and Alzheimer's brain tissues. Polymerization pattern, assembly kinetics and dynamics, critical concentration, GTPase activity, interaction with tau, intermolecular geometry, and conformational changes were explored via Förster Resonance Energy Transfer (FRET) and various spectroscopy methods. Results showed slower MT assembly process in samples from the brains of people with AD compared with normal young and aged brains. This observation was characterized by prolonged lag phase and increased critical and inactive concentration of tubulin. In addition, the GTPase activity in samples from AD brains was significantly higher than in both normal young and normal aged samples, concurrent with profound conformational changes and contracted intermolecular MT-tau distances as revealed by FRET. These alterations were partially restored in the presence of a microtubule stabilizer, paclitaxel. We proposed that alterations of both tubulin function and GTPase activity may be involved in the molecular neuropathogenesis of AD, thus providing new avenues for therapeutic approaches.
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September 2020

Cyclooxygenase enzyme and PGE2 expression in patients with functional and non-functional pituitary adenomas.

BMC Endocr Disord 2020 Mar 14;20(1):39. Epub 2020 Mar 14.

Department of Biochemistry, School of Medicine, Iran University of Medical Sciences, P.O. Box: 1449614535, Tehran, Iran.

Background: Pituitary adenomas as multifactorial intracranial neoplasms impose a massive burden of morbidity on patients and characterizing the molecular mechanism underlying their pathogenesis has received considerable attention. Despite the appealing role of cyclooxygenase enzymes and their bioactive lipid products in cancer pathogenesis, their relevance to pituitary adenoma pathogenesis is debated and yet to be determined. Thus, the current study perused this relevance.

Methods: The expression level of the isoforms of cyclooxygenase (COX-1 and COX-2) was evaluated in hormone-secreting and in-active pituitary adenoma tumors and normal pituitary tissues through Real-Time PCR. The level of PGE2, as the main product of enzymes, was assessed using enzyme immunoassay kits in patients and healthy subjects.

Results: The results of the current study demonstrated that COX-1 and COX-2 expression levels were increased in pituitary tumors including non-functional pituitary adenoma (NFPA), acromegaly, Cushing's disease and prolactinoma compared with normal pituitary tissues. A significant expression level of COX-2 was observed in NFPA compared with the other pituitary tumors. Furthermore, the COX-2 expression level was significantly increased in macroadenoma and invasive tumors. The level of PGE2 was consistent with COX enzymes enhanced in pituitary adenoma tumors compared with healthy pituitary tissue. A significant elevation in the PGE2 level was detected in NFPA compared with hormone-secreting pituitary tumors. Additionally, the PGE2 level was increased in macroadenoma compared with microadenoma and in invasive compared with non-invasive pituitary tumors. The diagnostic values of cyclooxygenase isoforms and PGE2 were considerable between patients and healthy groups; however, COX-2 revealed more value in distinguishing endocrinologically active and non-active pituitary tumors.

Conclusions: Data from the current study provides expression patterns of COX-1, COX-2 and PGE2 in prevalent pituitary tumors and their association with patients' clinical features which may open up new molecular targets for early diagnosis/follow up of pituitary tumor growth.
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March 2020

Up-regulation of 15-lipoxygenase enzymes and products in functional and non-functional pituitary adenomas.

Lipids Health Dis 2019 Jul 9;18(1):152. Epub 2019 Jul 9.

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

Background: Pituitary adenoma accounts as a complex and multifactorial intracranial neoplasm with wide range of clinical symptoms which its underlying molecular mechanism has yet to be determined. The bioactive lipid mediators received attentions toward their contribution in cancer cell proliferation, progression and death. Amongst, 15-Lipoxygense (15-Lox) enzymes and products display appealing role in cancer pathogenesis which their possible effect in pituitary adenoma tumor genesis is perused in the current study.

Methods: The 15-Lipoxygenses isoforms expression level was evaluated in tumor tissues of prevalent functional and non-functional pituitary adenomas and normal pituitary tissues via Real-Time PCR. The circulating levels of 15(S) HETE and 13(S) HODE as 15-Lox main products were assessed in serum of patients and healthy subjects using enzyme immunoassay kits.

Results: Our results revealed that 15-Lox-1 and 15-Lox-2 expression levels were elevated in tumor tissues of pituitary adenomas comparing to normal pituitary tissues. The elevated levels of both isoforms were accompanied with 15(S) HETE and 13(S) HODE elevation in the serum of patients. The 15-Lox-1 expression and activity was higher in invasive tumors as well as tumors with bigger size indicating the possible pro-tumorigenic role of 15-Lox-1, more than 15-Lox-2 in pituitary adenomas. The diagnostic value of 15-Lipoxygense isoforms and products were considerable between patients and healthy groups.

Conclusion: The possible involvement of 15-Lipoxygense pathway especially 15-Lox-1 in the regulation of pituitary tumor growth and progression may open up new molecular mechanism regarding pituitary adenoma pathogenesis and might shed light on its new therapeutic strategies.
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July 2019

Sudden Death Following Exercise; a Case Series.

Emerg (Tehran) 2016 ;4(2):97-100

Forensic Medicine Department, Shahid Beheshti University of Medical Sciences, Tehran, Iran.

Introduction: Natural and unexpected death that happens within less than one hour of first symptom occurrence is called sudden death. Cardiovascular diseases are the main known reason of sudden death and more than 75% of sudden deaths in athletes are assigned to it. Here we reported the autopsy results of all cases with sudden death following exercise that were referred to forensic center of Tehran, Iran, from 2009 to 2014.

Methods: In this cross sectional study all subjects who were registered to forensic medicine center of Tehran, Iran, from 2009 to 2014, as a case of sudden death following exercise were evaluated. Demographic data and medical history as well as autopsy and toxicology findings were retrospectively gathered using profiles of the deceased. Results were reported using descriptive analysis.

Results: 14 cases were registered as sudden death following exercise in forensic medicine profiles during the study period. Exploring the files of the mentioned deceased, revealed five non-compatible cases in this regard. Finally, 9 eligible cases were enrolled (88.9% male). The mean age of the deceased was 28.66 ± 10.86 years (range: 7 - 40). Toxicological tests were available for 7 cases, one of which was positive for tramadol. Sudden death following football was reported most frequently (44.4%). Only 3 (33.3%) cases had herald signs such as chest pain, syncope, or loss of consciousness. 1 case (11.11%) had a positive history of sudden death in relatives.

Conclusion: Although most sudden death victims are asymptomatic until the event, all those who suffer from symptoms such as chest pain, shortness of breath, dizziness, fatigue and irregular heart rate during physical activities, should be screened regarding common probable causes of sudden death.
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June 2016