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https://www.readbyqxmd.com/read/29790997/a-multi-institutional-study-of-independent-calculation-verification-in-inhomogeneous-media-using-a-simple-and-effective-method-of-heterogeneity-correction-integrated-with-the-clarkson-method
#1
Shunta Jinno, Hidenobu Tachibana, Shunsuke Moriya, Norifumi Mizuno, Ryo Takahashi, Tatsuya Kamima, Satoru Ishibashi, Masanori Sato
In inhomogeneous media, there is often a large systematic difference in the dose between the conventional Clarkson algorithm (C-Clarkson) for independent calculation verification and the superposition-based algorithms of treatment planning systems (TPSs). These treatment site-dependent differences increase the complexity of the radiotherapy planning secondary check. We developed a simple and effective method of heterogeneity correction integrated with the Clarkson algorithm (L-Clarkson) to account for the effects of heterogeneity in the lateral dimension, and performed a multi-institutional study to evaluate the effectiveness of the method...
May 21, 2018: Journal of Radiation Research
https://www.readbyqxmd.com/read/29788114/magnolol-inhibits-human-glioblastoma-cell-migration-by-regulating-n-cadherin
#2
Yu-Chen Cheng, Min-Jen Tsao, Chen-Yang Chiu, Po-Chieh Kan, Ying Chen
Glioblastoma is a primary malignant brain tumor with a poor prognosis. An effective treatment for glioblastoma is needed. Magnolol is a natural compound from Magnolia officinalis suggested to have antiproliferative activity. The aim of this research was to investigate the anticancer effects of magnolol in glioma, with an emphasis on migration and the underlying mechanism. Magnolol decreased the expression of focal adhesion-related proteins and inhibited LN229 and U87MG glioma cell migration. The levels of phosphorylated myosin light chain (p-MLC), phosphorylated myosin light chain kinase and myosin phosphatase target subunit 1 were reduced in response to magnolol treatment...
June 1, 2018: Journal of Neuropathology and Experimental Neurology
https://www.readbyqxmd.com/read/29786744/mir%C3%A2-133b-regulates-proliferation-and-apoptosis-in-high%C3%A2-glucose%C3%A2-induced-human-retinal-endothelial-cells-by-targeting-ras-homolog-family-member-a
#3
Jun Yao, Jihong Wang, Yong Yao, Kelei Wang, Qianqian Zhou, Ying Tang
The aim of the present study was to investigate the role of microRNA (miR)‑133b in high‑glucose‑induced human retinal endothelial cells (hRECs), particularly regarding its potential targeting of ras homolog family member A (RhoA). To establish the high‑glucose‑induced diabetic retinopathy (DR) model, hRECs were cultured in high‑glucose medium for 1, 2 and 3 days. An Annexin allophycocyanin (APC)/7‑aminoactinomycin D (7‑AAD) staining assay was performed to measure the apoptosis of hRECs. Next, the cells were transfected with miR‑133b inhibitors or mimics, and the cell proliferation and apoptosis were measured by MTT and Annexin‑APC/7‑AAD staining assays, respectively...
May 18, 2018: International Journal of Molecular Medicine
https://www.readbyqxmd.com/read/29785049/involvement-of-inhibitor-kappa-b-kinase-2-ikk2-in-the-regulation-of-vascular-tone
#4
Youngin Kwon, Soo-Kyoung Choi, Seonhee Byeon, Young-Ho Lee
Inhibitor kappa B kinase 2 (IKK2) plays an essential role in the activation of nuclear factor kappa B (NF-kB). Recently, it has been suggested that IKK2 acts as a myosin light chain kinase (MLCK) and contributes to vasoconstriction in mouse aorta. However, the underlying mechanisms are still unknown. Therefore, we investigated whether IKK2 acts as a MLCK or regulates the activity of myosin light chain phosphatase (MLCP). Pressure myograph was used to measure vascular tone in rat mesenteric arteries. Immunofluorescence staining was performed to identify phosphorylation levels of MLC (ser19), MYPT1 (thr853 and thr696) and CPI-17 (thr38)...
May 21, 2018: Laboratory Investigation; a Journal of Technical Methods and Pathology
https://www.readbyqxmd.com/read/29781138/comparison-of-the-progressive-resolution-optimizer-and-photon-optimizer-in-vmat-optimization-for-stereotactic-treatments
#5
Han Liu, Benjamin Sintay, Keith Pearman, Qingyang Shang, Lane Hayes, Jacqueline Maurer, Caroline Vanderstraeten, David Wiant
The photon optimization (PO) algorithm was recently released by Varian Medical Systems to improve volumetric modulated arc therapy (VMAT) optimization within Eclipse (Version 13.5). The purpose of this study is to compare the PO algorithm with its predecessor, progressive resolution optimizer (PRO) for lung SBRT and brain SRS treatments. A total of 30 patients were selected retrospectively. Previously, all the plans were generated with the PRO algorithm within Eclipse Version 13.6. In the new version of PO algorithm (Version 15), dynamic conformal arcs (DCA) were first conformed to the target, then VMAT inverse planning was performed to achieve the desired dose distributions...
May 20, 2018: Journal of Applied Clinical Medical Physics
https://www.readbyqxmd.com/read/29777595/a-ring-based-compensator-imrt-system-optimized-for-low-and-middle-income-countries-design-and-treatment-planning-study
#6
Jonathon Van Schelt, Daniel Smith, Nicholas Fong, Dolla Toomeh, Patricia A Sponseller, Derek W Brown, Meghan W Macomber, Nina A Mayr, Shilpen Patel, Adam Shulman, G V Subrahmanyam, K Govindarajan, Eric C Ford
PURPOSE: We propose a novel compensator-based IMRT system designed to provide a simple, reliable, and cost-effective adjunct technology, with the goal of expanding global access to advanced radiotherapy techniques. The system would employ easily-reusable tungsten bead compensators that operate independent of a gantry (e.g. mounted in a ring around the patient). Thereby the system can be retrofitted to existing linac and cobalt teletherapy units. This study explores the quality of treatment plans from the proposed system and the dependence on associated design parameters...
May 19, 2018: Medical Physics
https://www.readbyqxmd.com/read/29770241/methods-for-quantitative-measurement-of-tooth-wear-using-the-area-and-volume-of-virtual-model-cusps
#7
Soo-Hyun Kim, Young-Seok Park, Min-Kyoung Kim, Sulhee Kim, Seung-Pyo Lee
Purpose: Clinicians must examine tooth wear to make a proper diagnosis. However, qualitative methods of measuring tooth wear have many disadvantages. Therefore, this study aimed to develop and evaluate quantitative parameters using the cusp area and volume of virtual dental models. Methods: The subjects of this study were the same virtual models that were used in our former study. The same age group classification and new tooth wear index (NTWI) scoring system were also reused...
April 2018: Journal of Periodontal & Implant Science
https://www.readbyqxmd.com/read/29764449/primo-software-as-a-tool-for-monte-carlo-simulations-of-intensity-modulated-radiotherapy-a-feasibility-study
#8
Alessandro Esposito, Sofia Silva, Jorge Oliveira, Joana Lencart, João Santos
BACKGROUND: IMRT provides higher dose conformation to the target and dose sparing to surrounding tissues than 3DCRT. Monte Carlo method in Medical Physics is not a novelty to approach dosimetric problems. A new PENELOPE based code named PRIMO recently was published. The most intriguing features of PRIMO are the user-friendly approach, the stand-alone property and the built-in definition of different linear accelerators models. Nevertheless, IMRT simulations are not yet implemented. METHODS: A Varian Trilogy with a Millennium120 MLC and a Varian Novalis with 120HD MLC were studied...
May 15, 2018: Radiation Oncology
https://www.readbyqxmd.com/read/29761625/beam-focal-spot-position-determination-for-an-elekta-linac-with-the-agility-%C3%A2-head-practical-guide-with-a-ready-to-go-procedure
#9
Jacek M Chojnowski, Lee M Taylor, Jonathan R Sykes, David I Thwaites
A novel phantomless, EPID-based method of measuring the beam focal spot offset of a linear accelerator was proposed and validated for Varian machines. In this method, one set of jaws and the MLC were utilized to form a symmetric field and then a 180o collimator rotation was utilized to determine the radiation isocenter defined by the jaws and the MLC, respectively. The difference between these two isocentres is directly correlated with the beam focal spot offset of the linear accelerator. In the current work, the method has been considered for Elekta linacs...
May 14, 2018: Journal of Applied Clinical Medical Physics
https://www.readbyqxmd.com/read/29761173/liver-enriched-transcription-factor-expression-relates-to-chronic-hepatic-failure-in-humans
#10
Jorge Guzman-Lepe, Eduardo Cervantes-Alvarez, Alexandra Collin de l'Hortet, Yang Wang, Wendy M Mars, Yoshinao Oda, Yuki Bekki, Masahiro Shimokawa, Huanlin Wang, Tomoharu Yoshizumi, Yoshihiko Maehara, Aaron Bell, Ira J Fox, Kazuki Takeishi, Alejandro Soto-Gutierrez
The mechanisms by which the liver fails in end-stage liver disease remain elusive. Disruption of the transcription factor network in hepatocytes has been suggested to mediate terminal liver failure in animals. However, this hypothesis remains unexplored in human subjects. To study the relevance of transcription factor expression in terminal stages of chronic liver failure in humans, we analyzed the expression of liver-enriched transcription factors (LETFs) hepatocyte nuclear factor (HNF)4α, HNF1α, forkhead box protein A2 (FOXA2), CCAAT/enhancer-binding protein (CEBP)α, and CEBPβ...
May 2018: Hepatology Communications
https://www.readbyqxmd.com/read/29749555/high-glucose-upregulates-myosin-light-chain-kinase-to-induce-microfilament-cytoskeleton-rearrangement-in-hippocampal-neurons
#11
Liying Zhu, Chengcheng Li, Guiqin Du, Meixiu Pan, Guoqi Liu, Wei Pan, Xing Li
Chronic hyperglycemia leads to myosin light chain kinase (MLCK) upregulation and induces neuronal damage. However, the underlying molecular mechanism of neuronal damage in hyperglycemia has not yet been fully elucidated. In the present study, hippocampal neuronal cells were cultured and treated with a high glucose concentration (45 mmol/l). The results demonstrated that high glucose induced shrinking of the synapses, nuclear shape irregularity and microfilament damage. Filamentous actin (F‑actin) filaments were rearranged, cell apoptosis rate was increased and the protein expression of MLCK and phosphorylated (p)‑MLC was upregulated...
May 3, 2018: Molecular Medicine Reports
https://www.readbyqxmd.com/read/29745009/a-fast-jaw-tracking-model-for-vmat-and-imrt-monte-carlo-simulations
#12
Reid Townson, Hilary Egglestone, Sergei Zavgorodni
Modern radiotherapy techniques involve routine use of volumetric arc therapy (VMAT) and intensity modulated radiotherapy (IMRT) with jaw-tracking - dynamic motion of the secondary collimators (jaws) in tandem with multi-leaf collimators (MLCs). These modalities require accurate dose calculations for the purposes of treatment planning and dose verification. Monte Carlo (MC) methods for radiotherapy dose calculation are widely accepted as capable of achieving high accuracy. This paper presents an efficiency-enhancement method for secondary collimator modeling, presented in the context of a tool for MC-based dose second checks...
May 9, 2018: Journal of Applied Clinical Medical Physics
https://www.readbyqxmd.com/read/29739431/optimal-collimator-rotation-based-on-the-outline-of-multiple-brain-targets-in-vmat
#13
Jung-In Kim, Beom Seok Ahn, Chang Heon Choi, Jong Min Park, So-Yeon Park
BACKGROUND: The aim of this study was to investigate the dosimetric quality in volumetric modulated arc therapy (VMAT) plans with optimal collimator angles that can represent the outline of multiple brain targets. METHODS: Twenty patients with multiple target volumes in the brain cases were selected retrospectively. To better represent the outline of the multiple brain targets, four conformal arc plans were generated for each patient using one full arc with four collimator settings...
May 9, 2018: Radiation Oncology
https://www.readbyqxmd.com/read/29735342/dabigatran-reduces-endothelial-permeability-through-inhibition-of-thrombin-induced-cytoskeleton-reorganization
#14
Hyun-Jung Choi, Na-Eun Kim, Jayoung Kim, Sunho An, Seung-Hee Yang, Jimin Ha, Sunghee Cho, Il Kwon, Young Dae Kim, Hyo Suk Nam, Ji Hoe Heo
Dabigatran etexilate (DE), a new oral anti-coagulant, is a direct thrombin inhibitor. Clinical trials showed the favorable benefit-to-risk profile of DE compared to warfarin for the prevention of ischemic stroke in patients with atrial fibrillation. Remarkably, patients treated with dabigatran showed reduced rates of intracerebral hemorrhage compared to warfarin. As the breakdown of endothelial barrier integrity is associated with hemorrhagic events and as thrombin increases endothelial permeability, we hypothesized that dabigatran preserves the endothelial barrier by inhibiting thrombin-induced permeability...
April 25, 2018: Thrombosis Research
https://www.readbyqxmd.com/read/29732341/comparison-and-evaluation-of-different-treatment-plans-with-ifrt-field-and-6-and-18-mv-energies-in-hodgkin-s-lymphoma-involvement-neck-and-mediastinum
#15
M B Tavakoli, M Maleki, A Akhavan, T Hadisinia, I Abedi, A Amouheidari
Background: Radiotherapy with large mantle field is an effective technique in increasing the risk of secondary cancers among HL (Hodgkin Lymphoma) patients; therefore, it is essential to choose an effective treatment field including the least medical conditions in radiotherapy. Objective: The present study aimed to plan separate fields for neck and mediastinum using various energies, to compare dose distribution with MLC and to block field formation. Materials and Methods: In this study, 3D conformal treatments, Siemens Oncor accelerator equipped with multi-leaf collimator (MLC) were performed to create anterior-posterior fields...
March 2018: Journal of Biomedical Physics & Engineering
https://www.readbyqxmd.com/read/29730311/sodium-tanshinone-iia-sulfonate-promotes-endothelial-integrity-via-regulating-ve-cadherin-dynamics-and-rhoa-rock-mediated-cellular-contractility-and-prevents-atorvastatin-induced-intracerebral-hemorrhage-in-zebrafish
#16
Zhong-Yan Zhou, Bin Huang, Shang Li, Xiao-Hui Huang, Jing-Yi Tang, Yiu Wa Kwan, Pui Man Hoi, Simon Ming-Yuen Lee
Impaired vascular integrity leads to serious cerebral vascular diseases such as intracerebral hemorrhage (ICH). In addition, high-dose statin therapy is suggested to cause increased ICH risk due to unclear effects of general inhibition of 3-hydroxy-3-methylglutaryl-CoA reductase (HMGCR) on the vascular system. Here we evaluated the protective effects of sodium tanshinone IIA sulfonate (STS), which has high efficacy and safety in clinical studies of ischemic stroke, by using atorvastatin (Ator) induced ICH zebrafish embryos and human umbilical vein endothelial cells (HUVECs)...
May 3, 2018: Toxicology and Applied Pharmacology
https://www.readbyqxmd.com/read/29721190/cd200fc-enhances-anti-tumoral-immune-response-and-inhibits-visceral-metastasis-of-breast-carcinoma
#17
Nuray Erin, Gamze Tanrıöver, Anna Curry, Muhlis Akman, Özlem Duymuş, Reg Gorczynski
CD200 is a widely expressed cell surface glycoprotein that inhibits excessive inflammation in autoimmunity, transplantation, and viral infections. We previously observed that visceral metastasis of highly aggressive and inflammatory 4THM breast carcinoma cells was markedly decreased in CD200 transgenic mice. The goal of this study was to determine whether exogenous exposure to CD200fc mimics the effects of endogenously over expressed CD200. Female BALB/c mice were injected with CD200fc two times a week for five times...
April 10, 2018: Oncotarget
https://www.readbyqxmd.com/read/29705681/midlevel-constraint-without-stem-extensions-in-primary-total-knee-arthroplasty-provides-stability-without-compromising-fixation
#18
David A Crawford, Jesua I Law, Adolph V Lombardi, Keith R Berend
BACKGROUND: Many total knee arthroplasty (TKA) systems allow for so-called midlevel constraint (MLC) articular bearings that can be used with primary implants. The purpose of this study is to report the early outcomes with MLC bearings in primary TKA. MATERIALS/METHODS: From December 2005 to June 2015, minimum 2-year follow-up was available on 96 patients (103 TKA) who underwent primary TKA with an MLC bearing using the Vanguard Total Knee System. Outcomes included pain, Knee Society clinical and functional score, range of motion, and need for revision...
April 9, 2018: Journal of Arthroplasty
https://www.readbyqxmd.com/read/29698717/inhibition-of-prostatic-smooth-muscle-contraction-by-the-inhibitor-of-g-protein-coupled-receptor-kinase-2-3-cmpd101
#19
Qingfeng Yu, Christian Gratzke, Yiming Wang, Annika Herlemann, Frank Strittmatter, Beata Rutz, Christian G Stief, Martin Hennenberg
Alpha1-adrenoceptors induce prostate smooth muscle contraction, and hold a prominent role for pathophysiology and therapy of lower urinary tract symptoms in benign prostatic hyperplasia. G protein-coupled receptors are regulated by posttranslational regulation, including phosphorylation by G protein-coupled receptor kinases 2 and 3 (GRK2/3). Although posttranslational adrenoceptor regulation has been recently suggested to occur in the prostate, this is still marginally understood. With the newly developed CMPD101, a small molecule with assumed specificity for GRK2/3 is now available...
April 23, 2018: European Journal of Pharmacology
https://www.readbyqxmd.com/read/29685425/pre-treatment-verification-of-lung-sbrt-vmat-plans-with-delivery-errors-toward-a-better-understanding-of-the-gamma-index-analysis
#20
Thahabah Alharthi, Elise M Pogson, Sankar Arumugam, Lois Holloway, David Thwaites
PURPOSE: To study the sensitivity of the ArcCHECK in detecting delivery errors for lung stereotactic body radiotherapy (SBRT) using the Volumetric Modulated Arc Therapy (VMAT) technique and to evaluate the sensitivity of eight global and local gamma tolerances with different cut-off percentages. METHODS: Baseline VMAT plans were generated for 15 lung SBRT patients. We delivered the smallest errors(gantry, collimator, and multileaf collimator MLC) which had ≥ ±2% dose difference in the modified treatment plans compared to the baseline plan (the clinical significance of those errors were assessed in our previous study...
April 20, 2018: Physica Medica: PM
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