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https://www.readbyqxmd.com/read/28103599/evaluations-of-intravenous-administration-of-cd34-human-umbilical-cord-blood-cells-in-a-mouse-model-of-neonatal-hypoxic-ischemic-encephalopathy
#1
Makiko Ohshima, Akihiko Taguchi, Yoshiaki Sato, Yuko Ogawa, Satoshi Saito, Kenichi Yamahara, Masafumi Ihara, Mariko Harada-Shiba, Tomoaki Ikeda, Tomohiro Matsuyama, Masahiro Tsuji
Several cell therapies have been explored as novel therapeutic strategies for neonatal encephalopathy because the benefits of current treatments are limited. We previously reported that intravenous administration of human umbilical cord blood (hUCB) CD34+ cells (hematopoietic stem cells/endothelial progenitor cells) at 48 h after insult exerts therapeutic effects in neonatal mice with stroke, i.e., permanent middle cerebral artery occlusion. Although neonatal stroke and hypoxic-ischemic encephalopathy (HIE) are grouped under the term "neonatal encephalopathy," their pathogenesis differs...
January 20, 2017: Developmental Neuroscience
https://www.readbyqxmd.com/read/28079313/postischemic-inflammation-in-acute-stroke
#2
REVIEW
Simone Vidale, Arturo Consoli, Marco Arnaboldi, Domenico Consoli
Cerebral ischemia is caused by arterial occlusion due to a thrombus or an embolus. Such occlusion induces multiple and concomitant pathophysiological processes that involve bioenergetic failure, acidosis, loss of cell homeostasis, excitotoxicity, and disruption of the blood-brain barrier. All of these mechanisms contribute to neuronal death, mainly via apoptosis or necrosis. The immune system is involved in this process in the early phases after brain injury, which contributes to potential enlargement of the infarct size and involves the penumbra area...
January 2017: Journal of Clinical Neurology
https://www.readbyqxmd.com/read/28078626/time-course-investigation-of-blood-brain-barrier-permeability-and-tight-junction-protein-changes-in-a-rat-model-of-permanent-focal-ischemia
#3
Peng Liu, Rui Zhang, Danyang Liu, Jinling Wang, Chunling Yuan, Xuemei Zhao, Yinjie Li, Xuefei Ji, Tianyan Chi, Libo Zou
Permanent middle cerebral artery occlusion (pMCAO) is an animal model that is widely used to simulate human ischemic stroke. However, the timing of the changes in the expression of tight junction (TJ) proteins and synaptic proteins associated with pMCAO remain incompletely understood. Therefore, to further explore the characteristics and mechanisms of blood-brain barrier (BBB) damage during cerebral ischemic stroke, we used a pMCAO rat model to define dynamic changes in BBB permeability within 120 h after ischemia in order to examine the expression levels of the TJ proteins claudin-5 and occludin and the synaptic proteins synaptophysin (SYP) and postsynaptic density protein 95 (PSD95)...
January 11, 2017: Journal of Physiological Sciences: JPS
https://www.readbyqxmd.com/read/28068417/preserved-collateral-blood-flow-in-the-endovascular-m2cao-model-allows-for-clinically-relevant-profiling-of-injury-progression-in-acute-ischemic-stroke
#4
Philip Little, Ola Kvist, Rikard Grankvist, Stefan Jonsson, Peter Damberg, Michael Söderman, Fabian Arnberg, Staffan Holmin
Interventional treatment regimens have increased the demand for accurate understanding of the progression of injury in acute ischemic stroke. However, conventional animal models severely inhibit collateral blood flow and mimic the malignant infarction profile not suitable for treatment. The aim of this study was to provide a clinically relevant profile of the emergence and course of ischemic injury in cases suitable for acute intervention, and was achieved by employing a M2 occlusion model (M2CAO) that more accurately simulates middle cerebral artery (MCA) occlusion in humans...
2017: PloS One
https://www.readbyqxmd.com/read/28065778/protective-effects-of-tongxinluo-on-cerebral-ischemia-reperfusion-injury-related-to-connexin-43-calpain-ii-bax-caspase-3-pathway-in-rat
#5
Xiao Cheng, Zijun Hou, Jingbo Sun, Yan Huang, Lixin Wang, Ziyi Zhou, Li-Hua Zhou, Yefeng Cai
ETHNOPHARMACOLOGICAL RELEVANCE: Tongxinluo (TXL) is a multifunctional traditional Chinese medicine and has been widely used in the treatment of cardiovascular and cerebrovascular diseases. Numerous studies demonstrate that TXL is a novel neuroprotective drug, however, the mechanisms are largely unknown. AIM OF THE STUDY: we aimed to demonstrate the protective effect of TXL on cerebral ischemia/reperfusion (I/R) injury and provide the evidence for the involvement of Connexin 43/Calpain II/ Bax/Caspase-3 pathway in TXL-mediated neuroprotection...
January 5, 2017: Journal of Ethnopharmacology
https://www.readbyqxmd.com/read/28064357/ischemic-stroke-experimental-models-and-reality
#6
REVIEW
Clemens J Sommer
The vast majority of cerebral stroke cases are caused by transient or permanent occlusion of a cerebral blood vessel ("ischemic stroke") eventually leading to brain infarction. The final infarct size and the neurological outcome depend on a multitude of factors such as the duration and severity of ischemia, the existence of collateral systems and an adequate systemic blood pressure, etiology and localization of the infarct, but also on age, sex, comorbidities with the respective multimedication and genetic background...
January 7, 2017: Acta Neuropathologica
https://www.readbyqxmd.com/read/28048779/su-f-t-28-evaluation-of-bebig-hdr-co-60-after-loading-system-for-skin-cancer-treatment-using-conical-surface-applicator
#7
H Safigholi, A S Meigooni, D Han, A Soliman, W Y Song
PURPOSE: To evaluate the possibility of utilizing the BEBIG HDR 60Co remote after-loading system for malignant skin surface treatment using Monte Carlo (MC) simulation technique. METHODS: First TG-43 parameters of BEBIG-Co-60 and Nucletron Ir-192-mHDR-V2 brachytherapy sources were simulated using MCNP6 code to benchmark the sources against the literature. Second a conical tungsten-alloy with 3-cm diameter of Planning-Target-Volume (PTV) at surface for use with a single stepping HDR source is designed...
June 2016: Medical Physics
https://www.readbyqxmd.com/read/28048763/su-g-brc-10-feasibility-of-a-web-based-monte-carlo-simulation-tool-for-dynamic-electron-arc-radiotherapy-dear
#8
A Rodrigues, D Sawkey, Q Wu
PURPOSE: DEAR is a radiation therapy technique utilizing synchronized motion of gantry and couch during delivery to optimize dose distribution homogeneity and penumbra for treatment of superficial disease. Dose calculation for DEAR is not yet supported by commercial TPSs. The purpose of this study is to demonstrate the feasibility of using a web-based Monte Carlo (MC) simulation tool (VirtuaLinac) to calculate dose distributions for a DEAR delivery. METHODS: MC simulations were run through VirtuaLinac, which is based on the GEANT4 platform...
June 2016: Medical Physics
https://www.readbyqxmd.com/read/28048717/mo-fg-202-09-virtual-imrt-qa-using-machine-learning-a-multi-institutional-validation
#9
G Valdes, M Chan, R Scheuermann, J Deasy, T Solberg
PURPOSE: To validate a machine learning approach to Virtual IMRT QA for accurately predicting gamma passing rates using different QA devices at different institutions. METHODS: A Virtual IMRT QA was constructed using a machine learning algorithm based on 416 IMRT plans, in which QA measurements were performed using diode-array detectors and a 3%local/3mm with 10% threshold. An independent set of 139 IMRT measurements from a different institution, with QA data based on portal dosimetry using the same gamma index and 10% threshold, was used to further test the algorithm...
June 2016: Medical Physics
https://www.readbyqxmd.com/read/28048679/su-f-t-75-dosimetry-considerations-in-the-use-of-hanging-eye-block-for-lesions-of-the-conjunctiva
#10
Z Grelewicz, B Lee, D Cutright, Z Kang, M Gopalakrishnan, V Sathiaseelan, H Zhang
PURPOSE: Superficial lesions in the conjunctiva are frequently treated with en face electrons, using a hanging block to spare dose to the lens of the eye. Dose to the tumor and lens depend on the design and setup of the block and supporting apparatus. We performed in phantom measurements in order to characterize the dose sparing effects of the block as well as the under-dosing effect under the supporting apparatus for 6 MeV treatment. METHODS: The commercial hanging block studied uses a 1...
June 2016: Medical Physics
https://www.readbyqxmd.com/read/28048550/su-f-t-481-physics-evaluation-of-a-newly-released-incise%C3%A2-multileaf-collimator-for-cyberknife-m6%C3%A2-system
#11
L Wang, E Chin, A Lo
PURPOSE: This work reports the results of the physics evaluation of a newly released InCise™2 Multileaf Collimator (MLC) installed in our institution. METHODS: Beam property data was measured with unshielded diode and EBT2 films. The measurements included MLC leaf transmission, beam profiles, output factors and tissue-phantom ratios. MLC performance was evaluated for one month after commissioning. Weekly Garden Fence tests were performed for leaf / bank positioning in standard (A/P) and clinically relevant non-standard positions, before and after MLC driving exercises of 10+ minutes...
June 2016: Medical Physics
https://www.readbyqxmd.com/read/28048519/su-f-t-316-a-model-to-deal-with-dosimetric-and-delivery-uncertainties-in-radiotherapy-treatment-planning
#12
P Haering, C Lang, M Splinter
PURPOSE: The conventional way of dealing with uncertainties resulting from dose calculation or beam delivery in IMRT, is to do verification measurements for the plan in question. Here we present an alternative based on recommendations given in the AAPM 142 report and treatment specific parameters that model the uncertainties for the plan delivery. METHODS: Basis of the model is the assignment of uncertainty parameters to all segment fields or control point sequences of a plan...
June 2016: Medical Physics
https://www.readbyqxmd.com/read/28048438/th-ab-bra-01-a-novel-doubly-focused-multileaf-collimator-design-for-mr-guided-radiation-therapy
#13
H Li, S Mutic, D Low, O Green, G Fought, I Kawrakow, A Sharma, S Shvartsman, J Dempsey
PURPOSE: To describe the physical and dosimetric properties of a novel double-stack multileaf collimator (MLC). METHODS: One of the compromises made in the MLC design has been to employ linear-motion singly-divergent shapes. Because the MLC leading edge moves linearly, it is rounded to provide a consistent, albeit compromised penumbra. The MLC employed in the new linac-based MR-IGRT unit is designed to be doubly focused in that each leaf moves in an arc centered at the source, and the sides of the leaves are machined such that they lie parallel to a line between the leaf edge and the source...
June 2016: Medical Physics
https://www.readbyqxmd.com/read/28048428/su-f-t-540-comprehensive-fluence-delivery-optimization-with-multileaf-collimation
#14
S Weppler, P McGeachy, J Villarreal-Barajas, R Khan
PURPOSE: Multileaf collimator (MLC) leaf sequencing is performed via commercial black-box implementations, on which a user has limited to no access. We have developed an explicit, generic MLC sequencing model to serve as a tool for future investigations of fluence map optimization, fluence delivery optimization, and rotational collimator delivery methods. METHODS: We have developed a novel, comprehensive model to effectively account for a variety of transmission and penumbra effects previously treated on an ad hoc basis in the literature...
June 2016: Medical Physics
https://www.readbyqxmd.com/read/28048393/su-f-t-529-dosimetric-investigation-of-a-rotating-gamma-ray-system-for-imagedguided-modulated-arc-radiotherapy
#15
C Ma, O Chibani, A Eldib, J Li, L Chen
PURPOSE: Because of their effectiveness and efficiency, rotational arc radiotherapy (MAT) techniques have been developed on both specialty machines such as Tomotherapy and conventional linear accelerators. This work investigates a new rotating Gamma therapy system for image guided MAT and SBRT of intra/extracranial tumors. METHODS: The CyberMAT system (Cyber Medical Corp., China) consists of a ring gantry with a gamma source (effective source size 1cm and 1.7cm respectively), a 120-leaf MLC, a kV CBCT and an EPID...
June 2016: Medical Physics
https://www.readbyqxmd.com/read/28048376/su-f-t-671-effects-of-collimator-material-on-proton-minibeams
#16
E Lee, J Eagle, G Sandison, N Cao, R Stewart, S Marsh, J Meyer
PURPOSE: To investigate the dosimetric effects of collimator material on spatially modulated proton minibeams (pMBRT). METHODS: pMBRT holds promise to exhibit shallow depth normal-tissue sparing effects similar to synchrotron based microbeams while also retaining potential for uniform dose distributions for tumor targets. TOPAS Monte Carlo simulations were performed for a 5cm thick multislit collimator with 0.3mm slits and 1mm center-to-center spacing for a 50.5MeV proton minibeam while varying collimator material between brass, tungsten, and iron...
June 2016: Medical Physics
https://www.readbyqxmd.com/read/28048261/su-g-jep2-11-polymer-gels-as-3d-qa-devices-in-magnetic-resonance-guided-radiation-therapy
#17
Y Roed, M Kadbi, J Wang, L Pinsky, G Ibbott
PURPOSE: To demonstrate the potential of polymer gels to serve as 3D QA devices in MR-guided radiotherapy. METHODS: Custom-designed polymer gel dosimeters (MGS Research, Madison, CT) were centered on the penumbras of a radiation field, parallel to the magnetic field lines inside a 1.5 T MR scanner integrated with a 7 MV linac (MR-Linac). 15 Gy were delivered perpendicular to the magnetic field. Coronal MR images were acquired with a 2D balanced-Fast Field Echo (b-FFE) sequence in real-time during irradiation and with a 2D spin echo sequence at different times after irradiation...
June 2016: Medical Physics
https://www.readbyqxmd.com/read/28048148/su-f-t-153-experimental-validation-and-calculation-benchmark-for-a-commercial-monte-carlo-pencil-beam-scanning-proton-therapy-treatment-planning-system-in-water
#18
L Lin, S Huang, M Kang, C Ainsley, P Hiltunen, R Vanderstraeten, J Lindberg, S Siljamaki, T Wareing, I Davis, A Barnett, J McGhee, T Solberg, J McDonough, C Simone
PURPOSE: Eclipse proton Monte Carlo AcurosPT 13.7 was commissioned and experimentally validated for an IBA dedicated PBS nozzle in water. Topas 1.3 was used to isolate the cause of differences in output and penumbra between simulation and experiment. METHODS: The spot profiles were measured in air at five locations using Lynx. PTW-34070 Bragg peak chamber (Freiburg, Germany) was used to collect the relative integral Bragg peak for 15 proton energies from 100 MeV to 225 MeV...
June 2016: Medical Physics
https://www.readbyqxmd.com/read/28048123/su-f-t-142-an-analytical-model-to-correct-the-aperture-scattered-dose-in-clinical-proton-beams
#19
B Sun, S Liu, T Zhang, T Zhao, D Yang, K Grantham, S Goddu, J Bradley, S Mutic
PURPOSE: Apertures or collimators are used to laterally shape proton beams in double scattering (DS) delivery and to sharpen the penumbra in pencil beam (PB) delivery. However, aperture-scattered dose is not included in the current dose calculations of treatment planning system (TPS). The purpose of this study is to provide a method to correct the aperture-scattered dose based on an analytical model. METHODS: A DS beam with a non-divergent aperture was delivered using a single-room proton machine...
June 2016: Medical Physics
https://www.readbyqxmd.com/read/28048102/su-f-t-131-no-increase-in-biological-effectiveness-through-collimator-scattered-low-energy-protons
#20
T Matsuura, S Takao, Y Matsuzaki, Y Fujii, T Fujii, K Maeda, H Ueda, H Koyano, K Umegaki, H Shirato
PURPOSE: To reduce the lateral penumbra of low-energy proton beams, brass collimators are often used in spot-scanning proton therapy (SSPT). This study investigates the increase in biological effectiveness through collimator scattered protons in SSPT. METHODS: The SSPT system of the Hokkaido University Hospital Proton Beam Therapy Center, which consists of a scanning nozzle, a 2-cm thick brass collimator, and a 4-cm thick energy absorber, was simulated with our validated Geant4 Monte Carlo code (ver...
June 2016: Medical Physics
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