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https://www.readbyqxmd.com/read/28445478/delayed-histochemical-alterations-within-the-neurovascular-unit-due-to-transient-focal-cerebral-ischemia-and-experimental-treatment-with-neurotrophic-factors
#1
Dominik Michalski, Roman Pitsch, Deepu R Pillai, Bianca Mages, Susanne Aleithe, Jens Grosche, Henrik Martens, Felix Schlachetzki, Wolfgang Härtig
Current stroke therapy is focused on recanalizing strategies, but neuroprotective co-treatments are still lacking. Modern concepts of the ischemia-affected neurovascular unit (NVU) and surrounding penumbra emphasize the complexity during the transition from initial damaging to regenerative processes. While early treatment with neurotrophic factors was shown to result in lesion size reduction and blood-brain barrier (BBB) stabilization, cellular consequences from these treatments are poorly understood. This study explored delayed cellular responses not only to ischemic stroke, but also to an early treatment with neurotrophic factors...
2017: PloS One
https://www.readbyqxmd.com/read/28444840/topas-simulation-of-the-mevion-s250-compact-proton-therapy-unit
#2
Michael Prusator, Salahuddin Ahmad, Yong Chen
As proton therapy becomes increasingly popular, so does the need for Monte Carlo simulation studies involving accurate beam line modeling of proton treatment units. In this study, the 24 beam configurations of the Mevion S250 proton therapy system installed recently at our institution were modeled using the TOolkit for PArticle Simulation (TOPAS) code. Pristine Bragg peak, spread out Bragg peak (SOBP), and lateral beam profile dose distributions were simulated and matched to the measurements taken during commissioning of the unit...
April 26, 2017: Journal of Applied Clinical Medical Physics
https://www.readbyqxmd.com/read/28443484/manual-aspiration-thrombectomy-with-a-penumbra-catheter-for-acute-anterior-cerebral-artery-occlusion
#3
Gyung Ho Chung, Hyo Sung Kwak, Jung Soo Park, Jong Myong Lee
Purpose The purpose of this article is to assess the efficacy and safety of manual aspiration thrombectomy (MAT) using a Penumbra catheter in patients with anterior cerebral artery (ACA) occlusions. Materials and methods From January 2012 to March 2016, 16 patients underwent MAT with Penumbra catheters using a proximal and distal supporting technique to treat ACA occlusions. We evaluated immediate angiographic results and clinical outcomes by reviewing patient electrical medical records. Results Of these patients, 11 had a complete obstruction of the distal internal carotid artery (ICA) and five had ACA and middle cerebral artery (MCA) occlusions...
January 1, 2017: Interventional Neuroradiology
https://www.readbyqxmd.com/read/28443061/a-linear-temporal-increase-in-thrombin-activity-and-loss-of-its-receptor-in-mouse-brain-following-ischemic-stroke
#4
Doron Bushi, Efrat Shavit Stein, Valery Golderman, Ekaterina Feingold, Orna Gera, Joab Chapman, David Tanne
BACKGROUND: Brain thrombin activity is increased following acute ischemic stroke and may play a pathogenic role through the protease-activated receptor 1 (PAR1). In order to better assess these factors, we obtained a novel detailed temporal and spatial profile of thrombin activity in a mouse model of permanent middle cerebral artery occlusion (pMCAo). METHODS: Thrombin activity was measured by fluorescence spectroscopy on coronal slices taken from the ipsilateral and contralateral hemispheres 2, 5, and 24 h following pMCAo (n = 5, 6, 5 mice, respectively)...
2017: Frontiers in Neurology
https://www.readbyqxmd.com/read/28442781/spreading-depolarization-remarkably-exacerbates-ischemia-induced-tissue-acidosis-in-the-young-and-aged-rat-brain
#5
Ákos Menyhárt, Dániel Zölei-Szénási, Tamás Puskás, Péter Makra, M Tóth Orsolya, Borbála É Szepes, Réka Tóth, Orsolya Ivánkovits-Kiss, Tihomir P Obrenovitch, Ferenc Bari, Eszter Farkas
Spreading depolarizations (SDs) occur spontaneously in the cerebral cortex of subarachnoid hemorrhage, stroke or traumatic brain injury patients. Accumulating evidence prove that SDs exacerbate focal ischemic injury by converting zones of the viable but non-functional ischemic penumbra to the core region beyond rescue. Yet the SD-related mechanisms to mediate neurodegeneration remain poorly understood. Here we show in the cerebral cortex of isoflurane-anesthetized, young and old laboratory rats, that SDs propagating under ischemic penumbra-like conditions decrease intra and- extracellular tissue pH transiently to levels, which have been recognized to cause tissue damage...
April 25, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28436705/pharmacologically-increasing-collateral-perfusion-during-acute-stroke-using-a-carboxyhemoglobin-gas-transfer-agent-sanguinate%C3%A2-in-spontaneously-hypertensive-rats
#6
Marilyn J Cipolla, Italo Linfante, Abe Abuchowski, Ronald Jubin, Siu-Lung Chan
Similar to patients with chronic hypertension, spontaneously hypertensive rats (SHR) develop fast core progression during middle cerebral artery occlusion (MCAO) resulting in large final infarct volumes. We investigated the effect of Sanguinate™ (SG), a PEGylated carboxyhemoglobin (COHb) gas transfer agent, on changes in collateral and reperfusion cerebral blood flow and brain injury in SHR during 2 h of MCAO. SG (8 mL/kg) or vehicle ( n = 6-8/group) was infused i.v. after 30 or 90 min of ischemia with 2 h reperfusion...
January 1, 2017: Journal of Cerebral Blood Flow and Metabolism
https://www.readbyqxmd.com/read/28430183/neuroprotectin-d1-upregulates-iduna-expression-and-provides-protection-in-cellular-uncompensated-oxidative-stress-and-in-experimental-ischemic-stroke
#7
Ludmila Belayev, Pranab K Mukherjee, Veronica Balaszczuk, Jorgelina M Calandria, Andre Obenaus, Larissa Khoutorova, Sung-Ha Hong, Nicolas G Bazan
Ring finger protein 146 (Iduna) facilitates DNA repair and protects against cell death induced by NMDA receptor-mediated glutamate excitotoxicity or by cerebral ischemia. Neuroprotectin D1 (NPD1), a docosahexaenoic acid (DHA)-derived lipid mediator, promotes cell survival under uncompensated oxidative stress (UOS). Our data demonstrate that NPD1 potently upregulates Iduna expression and provides remarkable cell protection against UOS. Iduna, which was increased by the lipid mediator, requires the presence of the poly(ADP-ribose) (PAR) sites...
April 21, 2017: Cell Death and Differentiation
https://www.readbyqxmd.com/read/28424292/loss-and-recovery-of-functional-connectivity-in-cultured-cortical-networks-exposed-to-hypoxia
#8
Joost le Feber, Niels Erkamp, Michel J A M van Putten, Jeannette Hofmeijer
In the core of a brain infarct, loss of neuronal function is followed by neuronal death within minutes. In an area surrounding the core (penumbra), some perfusion remains. Here, neurons initially remain structurally intact, but massive synaptic failure strongly reduces neural activity. Activity in the penumbra may eventually recover or further deteriorate towards massive cell death. Besides activity recovery, return of brain functioning requires restoration of connectivity. However, low activity has been shown to initiate compensatory mechanisms that affect network connectivity...
April 19, 2017: Journal of Neurophysiology
https://www.readbyqxmd.com/read/28422401/mlc-based-penumbra-softener-of-edw-borders-to-reduce-junction-inhomogeneities
#9
Stanislaw Szpala, Kirpal Kohli
Junctions of fields are known to be susceptible to developing cold or hot spots in the presence of even small geometrical misalignments. Reduction of these dose inhomogeneities can be accomplished through decreasing the dose gradients in the penumbra, but currently it cannot be done for enhanced dynamic wedges (EDW). An MLC-based penumbra softener was developed in the developer mode of TrueBeam linacs to reduce dose gradients across the side border of EDWs. The movement of each leaf was individually synchronized with the movement of the dynamic Y jaw to soften the penumbra in the same manner along the entire field border, in spite of the presence of the dose gradient of the EDW...
April 19, 2017: Journal of Applied Clinical Medical Physics
https://www.readbyqxmd.com/read/28414895/the-impact-of-ct-perfusion-threshold-on-predicted-viable-and-nonviable-tissue-volumes-in-acute-ischemic-stroke
#10
Xuya Huang, Dheeraj Kalladka, Bharath Kumar Cheripelli, Fiona Catherine Moreton, Keith W Muir
BACKGROUND AND PURPOSE: Perfusion imaging is used for patient selection in clinical practice and trials. Postprocessing and definitions of tissue viability are nevertheless not standardized. We compared the lesion volumes generated with two well-recognized perfusion tissue definitions in a single-center phase 2 thrombolysis study. METHODS: We analyzed perfusion imaging data from the Alteplase-Tenecteplase Trial Evaluation for Stroke Thrombolysis (ATTEST) study using two popular tissue viability thresholds (ischemic core definition: (1) cerebral blood volume < 2...
April 17, 2017: Journal of Neuroimaging: Official Journal of the American Society of Neuroimaging
https://www.readbyqxmd.com/read/28412316/differentiating-stroke-and-seizure-in-acute-setting-perfusion-computed-tomography
#11
Katarzyna Kubiak-Balcerewicz, Urszula Fiszer, Ewa Nagańska, Cezary Siemianowski, Aleksander Sobieszek, Agnieszka Witak-Grzybowska, Aldona Kosińska-Szot
BACKGROUND: Perfusion computed tomography (PCT) is part of acute stroke protocol in many hospitals; however, its clinical utility is still being disputed. Beyond its use in core and penumbra estimation, there is also a question about PCT role in stroke mimics diagnosis. Case series or small, retrospective studies showed equivocal results. This is the first published prospective, comparative study on PCT in differentiating stroke and seizure in acute setting. METHODS: Patients with acute focal neurologic deficits and without acute ischemic lesions on routine CT underwent PCT and electroencephalography (EEG) within 12 hours after symptom onset...
April 13, 2017: Journal of Stroke and Cerebrovascular Diseases: the Official Journal of National Stroke Association
https://www.readbyqxmd.com/read/28398927/triggering-receptor-expressed-on-myeloid-cells-2-a-novel-regulator-of-immunocyte-phenotypes-confers-neuroprotection-by-relieving-neuroinflammation
#12
Qian Zhai, Feng Li, Xiyao Chen, Ji Jia, Sisi Sun, Dandan Zhou, Lei Ma, Tao Jiang, Fuhai Bai, Lize Xiong, Qiang Wang
BACKGROUND: Microglia can not only detrimentally augment secondary injury but also potentially promote recovery. However, the mechanism underlying the regulation of microglial phenotypes after stroke remains unclear. METHODS: Mice were subjected to middle cerebral artery occlusion for 60 min. At 3 days after reperfusion, the effects of activation and suppression of triggering receptor expressed on myeloid cells 2 on immunocyte phenotypes (n = 5), neurobehavioral scores (n = 7), infarct volumes (n = 8), and neuronal apoptosis (n = 7) were analyzed...
April 10, 2017: Anesthesiology
https://www.readbyqxmd.com/read/28395963/dosimetric-impact-assessment-using-a-general-algorithm-in-geant4-simulations-for-a-complex-shaped-multileaf-collimator
#13
Á Perales, M A Cortés-Giraldo, H Miras, R Arráns, M I Gallardo
PURPOSE: We have developed an inhouse algorithm for the multileaf collimator (MLC) geometry model construction with an appropriate accuracy for dosimetric tests. Our purpose is to build a complex type of MLC and analyze the influence of the modeling parameters on the dose calculation. METHODS: Using radiochromic films as detector the following tests were done: (I) Density test field: to compare measured and calculated dose distributions in order to determine the tungsten alloy physical density value...
April 7, 2017: Physica Medica: PM
https://www.readbyqxmd.com/read/28392777/efficacy-of-cerebral-autoregulation-in-early-ischemic-stroke-predicts-smaller-infarcts-and-better-outcome
#14
Pedro Castro, Jorge Manuel Serrador, Isabel Rocha, Farzaneh Sorond, Elsa Azevedo
BACKGROUND AND PURPOSE: Effective cerebral autoregulation (CA) may protect the vulnerable ischemic penumbra from blood pressure fluctuations and minimize neurological injury. We aimed to measure dynamic CA within 6 h of ischemic stroke (IS) symptoms onset and to evaluate the relationship between CA, stroke volume, and neurological outcome. METHODS: We enrolled 30 patients with acute middle cerebral artery IS. Within 6 h of IS, we measured for 10 min arterial blood pressure (Finometer), cerebral blood flow velocity (transcranial Doppler), and end-tidal-CO2...
2017: Frontiers in Neurology
https://www.readbyqxmd.com/read/28392696/compound-porcine-cerebroside-and-ganglioside-injection-attenuates-cerebral-ischemia-reperfusion-injury-in-rats-by-targeting-multiple-cellular-processes
#15
Mingyang Wang, Yi Zhang, Lu Feng, Ji Zheng, Shujie Fan, Junya Liu, Nan Yang, Yanyong Liu, Pingping Zuo
BACKGROUND: Compound porcine cerebroside and ganglioside injection (CPCGI) is a neurotrophic drug used clinically to treat certain functional disorders of brain. Despite its extensive usage throughout China, the exact mechanistic targets of CPCGI are unknown. This study was carried out to investigate the protective effect of CPCGI against ischemic neuronal damage in rats with middle cerebral artery occlusion (MCAO) reperfusion injury and to investigate the neuroprotective mechanisms of CPCGI...
2017: Neuropsychiatric Disease and Treatment
https://www.readbyqxmd.com/read/28386041/prevalence-of-imaging-biomarkers-to-guide-the-planning-of-acute-stroke-reperfusion-trials
#16
Bin Jiang, Robyn L Ball, Patrik Michel, Tudor Jovin, Manisha Desai, Ashraf Eskandari, Zack Naqvi, Max Wintermark
BACKGROUND AND PURPOSE: Imaging biomarkers are increasingly used as selection criteria for stroke clinical trials. The goal of our study was to determine the prevalence of commonly studied imaging biomarkers in different time windows after acute ischemic stroke onset to better facilitate the design of stroke clinical trials using such biomarkers for patient selection. METHODS: This retrospective study included 612 patients admitted with a clinical suspicion of acute ischemic stroke with symptom onset no more than 24 hours before completing baseline imaging...
April 6, 2017: Stroke; a Journal of Cerebral Circulation
https://www.readbyqxmd.com/read/28385495/dosimetric-characterization-of-small-fields-using-a-plastic-scintillator-detector-a-large-multicenter-study
#17
Pietro Mancosu, Massimo Pasquino, Giacomo Reggiori, Laura Masi, Serenella Russo, Michele Stasi
PURPOSE: In modern radiation therapy accurate small fields dosimetry is a challenge and its standardization is fundamental to harmonize delivered dose in different institutions. This study presents a multicenter characterization of MLC-defined small field for Elekta and Varian linear accelerators. Measurements were performed using the Exradin W1 plastic scintillator detector. MATERIALS AND METHODS: The project enrolled 24 Italian centers. Each center performed Tissue Phantom Ratio (TPR), in-plane and cross-plane dose profiles of 0...
April 3, 2017: Physica Medica: PM
https://www.readbyqxmd.com/read/28381652/treatment-outcome-of-carotid-artery-stenting-underwent-within-14-days-of-stroke-onset-consideration-of-safety-and-efficacy-of-urgent-carotid-artery-stenting-for-neurologically-progressing-patients
#18
Yasuhisa Kanematsu, Junichiro Satomi, Kazuyuki Kuwayama, Izumi Yamaguchi, Shotaro Yoshioka, Tomoya Kinouchi, Yoshiteru Tada, Nobuaki Yamamoto, Shunji Matsubara, Koichi Satoh, Shinji Nagahiro
As the safety and effectiveness of urgent carotid artery stenting (CAS) for neurologically progressing patients remain controversial, we retrospectively analyzed the outcome of urgent CAS based on the patients' pathophysiological condition and neuroimaging findings. We divided 71 patients who underwent CAS within 14 days of stroke onset into two groups. Group 1 (n = 35) was comprised of patients with progressing neurologic signs and a reversible ischemic penumbra on magnetic resonance images (MRI). They were treated by urgent CAS...
April 6, 2017: Neurologia Medico-chirurgica
https://www.readbyqxmd.com/read/28367097/lyophilized-powder-of-catalpol-and-puerarin-protected-cerebral-vessels-from-ischemia-by-its-anti-apoptosis-on-endothelial-cells
#19
Yang Liu, Qing Tang, Siying Shao, Yi Chen, Weihai Chen, Xiaoyu Xu
Catalpol and puerarin are two monomers of Rehmannia glutinosa and Lobed Kudzuvine Root, which are two herbs commonly used together in ancient prescriptions of traditional Chinese medicine for cerebral ischemia. Our previous study shows that the lyophilized powder of the two monomers improved the outcome of cerebral ischemia excellently in rodents. However, if it protects vessels from ischemia is unknown. The present research studied the protection of lyophilized powder of catalpol and puerarin (CP) on endothelial cells and the relative mechanism in vivo and in vitro...
2017: International Journal of Biological Sciences
https://www.readbyqxmd.com/read/28367049/the-penumbra-obscura-stimulates-iris-neovascularisation-after-isolated-central-retinal-artery-occlusion
#20
David McLeod
No abstract text is available yet for this article.
April 2017: Korean Journal of Ophthalmology: KJO
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