147 research outputs found
Protective effects of Lithium on Sumatriptan-induced memory impairment in mice
Lithium is a drug used for the treatment of bipolar disorder. It has several mechanisms of action, and recently it is shown that lithium can antagonize the 5-HT1B/1D serotonin receptors. Sumatriptan is a 5- HT1B/1D receptor agonist used for the treatment of cluster headaches and migraine which might cause memory impairment as a potential side effect. In this study, effects of lithium on sumatriptan-induced memory impairment have been determined in a two trial recognition Y-maze and passive avoidance tests. Male mice weighing 25-30 g were divided into several groups randomly. In Y-maze test, effects of lithium (1,5,10,20,40,80 mg/kg) and sumatriptan (1,5,10 mg/kg) were assessed on memory acquisition, then lithium (0.1,1,10 mg/kg) and sumatriptan (1,10 mg/kg) were studied in passive avoidance test. Effects of lithium (1mg/kg) on sumatriptan (10 mg/kg)-induced memory impairment were studied in both of tests. The present study demonstrated that sumatriptan impaired memory in Y-maze and passive avoidance tests (P0.05), but significantly reversed sumatriptan-induced memory impairment in Y-maze and passive avoidance tests (P<0.001, P<0.05, respectively). It is concluded that lithium reverses the sumatriptan-induced memory impairment probably through 5-HT1B/1D receptors antagonism. © 2016 Tehran University of Medical Sciences. All rights reserved
Biology of biomechanics: Finite Element Analysis of a Statically Determinate System to Rotate the Occlusal Plane for Correction of Skeletal Class III Openbite Malocclusion
Introduction
In the absence of adequate animal or in-vitro models, the biomechanics of human malocclusion must be studied indirectly. Finite element analysis (FEA) is emerging as a clinical technology to assist in diagnosis, treatment planning, and retrospective analysis. The hypothesis tested is that instantaneous FEA can retrospectively simulate long-term mandibular arch retraction and occlusal plane rotation for the correction of a skeletal Class III malocclusion.
Methods
Seventeen published case reports were selected of patients treated with statically determinate mechanics using posterior mandible or infrazygomatic crest bone screw anchorage to retract the mandibular arch. Two-dimensional measurements were made for incisor and molar movements, mandibular arch rotation, and retraction relative to the maxillary arch. A patient with cone-beam computed tomography imaging was selected for a retrospective FEA.
Results
The mean age for the sample was 23.3 ± 3.3 years; there were 7 men and 10 women. Mean incisor movements were 3.35 ± 1.55 mm of retraction and 2.18 ± 2.51 mm of extrusion. Corresponding molar movements were retractions of 4.85 ± 1.78 mm and intrusions of 0.85 ± 2.22 mm. Retraction of the mandibular arch relative to the maxillary arch was 4.88 ± 1.41 mm. Mean posterior rotation of the mandibular arch was –5.76° ± 4.77° (counterclockwise). The mean treatment time (n = 16) was 36.2 ± 15.3 months. Bone screws in the posterior mandibular region were more efficient for intruding molars and decreasing the vertical dimension of the occlusion to close an open bite. The full-cusp, skeletal Class III patient selected for FEA was treated to an American Board of Orthodontics Cast-Radiograph Evaluation score of 24 points in about 36 months by en-masse retraction and posterior rotation of the mandibular arch: the bilateral load on the mandibular segment was about 200 cN. The mandibular arch was retracted by about 5 mm, posterior rotation was about 16.5°, and molar intrusion was about 3 mm. There was a 4° decrease in the mandibular plane angle to close the skeletal open bite. Retrospective sequential iterations (FEA animation) simulated the clinical response, as documented with longitudinal cephalometrics. The level of periodontal ligament stress was relatively uniform (<5 kPa) for all teeth in the mandibular arch segment.
Conclusions
En-masse retraction of the mandibular arch is efficient for conservatively treating a skeletal Class III malocclusion. Posterior mandibular anchorage causes intrusion of the molars to close the vertical dimension of the occlusion and the mandibular plane angle. Instantaneous FEA as modeled here could be used to reasonably predict the clinical results of an applied load
Assessment of patient dose in routine digital radiography in Iran
Background: The present study aimed to investgate patent dose in common X-ray examinatons to estmate effectve dose in the digital radiography in Iran. Materials and Methods: Entrance surface dose (ESD) was measured based on applied exposure parameters for the common actual examinaton; and then effectve dose (ED) was calculated by use of PCXMC software. The study was conducted on 15358 patents in 85 X-ray rooms; and the necessary data was collected for five age groups, 0-1 year, 1-5 years, 5-10 years, 10-15 years old and adults in each projecton. Results: The ranges of ESD and ED in different examinatons for all the age groups are 0.02-10.20 mGy and 2.42-378.96 μSv respectvely. Conclusion: The effectve dose as criteria can be used to reduce patents' doses. The special consideratons such as: adequate training of imaging staff; updatng clinical audits; patent dose consideratons; implementaton of systematc and regular quality assurance and quality control programs in medical imaging departments should be taken into account to optmize radiological practces. © 2020 Novin Medical Radiation Institute. All rights reserved
Thorax organ dose estimation in computed tomography based on patient CT data using Monte Carlo simulation
Background: This study presents pati ent specific and organ dose esti mati on in computed tomography (CT) imaging of thorax directly from pati ent CT image using Monte Carlo simulati on. Pati ent's CT image is considered as the pati ent specific phantom and the best representati ve of pati ent physical index in order to calculate specific organ dose. Materials and Methods: EGSnrc/BEAMnrc Monte Carlo (MC) System was used for CT scanner simulati on and DOSXYZnrc was used in order to produce pati ent specific phantom and irradiati on of photons to phantom in step and shoot mode (axial mode). In order to calculate pati ent thorax organ dose, pati ent CT image of thorax as voxelized phantom was divided to a 64x64x20 matrix and 6.25 x 6.25 x 6.25 mm3 voxel size and this phantom was imported to DOSXYZnrc code. MC results in unit of Gy/parti cle were converted to absorbed dose in unit of mGy by a conversion factor (CF). We calculated pati ent thorax organ dose in MC simulati on from all irradiated slices, in 120 kV and 80 kV photon energies. Results: Effecti ve dose was obtained from organ dose and organ weighti ng factor. Esophagus and spinal cord received the lowest, and bone received the highest dose. In our study, effecti ve dose in CT of thorax was 7.4 mSV and 1.8 mSv in 120 and 80 kV, respecti vely. Conclusion: The results of this study might be used to provide the actual pati ent organ dose in CT imaging and calculati on of real effecti ve dose based on organ dose
Standardized Treatment of Active Tuberculosis in Patients with Previous Treatment and/or with Mono-resistance to Isoniazid: A Systematic Review and Meta-analysis
Performing a systematic review of studies evaluating retreatment of tuberculosis or treatment of isoniazid mono-resistant infection, Dick Menzies and colleagues find a paucity of evidence to support the WHO-recommended regimen
Effect of Duration and Intermittency of Rifampin on Tuberculosis Treatment Outcomes: A Systematic Review and Meta-Analysis
In a systematic review of randomized controlled trials on tuberculosis treatment, Dick Menzies and colleagues find shorter courses of rifampin to be associated with poorer treatment outcomes
Pelvic trauma : WSES classification and guidelines
Complex pelvic injuries are among the most dangerous and deadly trauma related lesions. Different classification systems exist, some are based on the mechanism of injury, some on anatomic patterns and some are focusing on the resulting instability requiring operative fixation. The optimal treatment strategy, however, should keep into consideration the hemodynamic status, the anatomic impairment of pelvic ring function and the associated injuries. The management of pelvic trauma patients aims definitively to restore the homeostasis and the normal physiopathology associated to the mechanical stability of the pelvic ring. Thus the management of pelvic trauma must be multidisciplinary and should be ultimately based on the physiology of the patient and the anatomy of the injury. This paper presents the World Society of Emergency Surgery (WSES) classification of pelvic trauma and the management Guidelines.Peer reviewe
Development of a cell formation heuristic by considering realistic data using principal component analysis and Taguchi’s method
Over the last four decades of research, numerous cell formation algorithms have been developed and tested, still this research remains of interest to this day. Appropriate manufacturing cells formation is the first step in designing a cellular manufacturing system. In cellular manufacturing, consideration to manufacturing flexibility and productionrelated data is vital for cell formation. The consideration to this realistic data makes cell formation problemvery complex and tedious. It leads to the invention and implementation of highly advanced and complex cell formation methods. In this paper an effort has been made to develop a simple and easy to understand/implement manufacturing cell formation heuristic procedure with considerations to the number of production and manufacturing flexibility-related parameters. The heuristic minimizes inter-cellular movement cost/time. Further, the proposed heuristic is modified for the application of principal component analysis and Taguchi's method. Numerical example is explained to illustrate the approach. A refinement in the results is observed with adoption of principal component analysis and Taguchi's method
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