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排序方式: 共有250条查询结果,搜索用时 93 毫秒
1.
Peffault de Latour Rgis Huynh Lynn Ivanova Jasmina I. Totev Todor Bilginsoy Mehmet Antin Joseph Roy Anuja Duh Mei Sheng 《Annals of hematology》2020,99(4):743-752
Annals of Hematology - This study assessed treatment patterns and healthcare resource utilization (HRU) of patients with severe aplastic anemia (SAA) with insufficient response to immunosuppressive... 相似文献
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3.
Keall PJ Todor AD Vedam SS Bartee CL Siebers JV Kini VR Mohan R 《Medical physics》2004,31(12):3492-3499
Four-dimensional (4D) radiotherapy delivery to dynamically moving tumors requires a real-time signal of the tumor position as a function of time so that the radiation beam can continuously track the tumor during the respiration cycle. The aim of this study was to develop and evaluate an electronic portal imaging device (EPID)-based marker-tracking system that can be used for real-time tumor targeting, or 4D radiotherapy. Three gold cylinders, 3 mm in length and 1 mm in diameter, were implanted in a dynamic lung phantom. The phantom range of motion was 4 cm with a 3-s "breathing" period. EPID image acquisition parameters were modified, allowing image acquisition in 0.1 s. Images of the stationary and moving phantom were acquired. Software was developed to segment automatically the marker positions from the EPID images. Images acquired in 0.1 s displayed higher noise and a lower signal-noise ratio than those obtained using regular (> 1 s) acquisition settings. However, the markers were still clearly visible on the 0.1-s images. The motion of the phantom blurred the images of the markers and further reduced the signal-noise ratio, though they could still be successfully segmented from the images in 10-30 ms of computation time. The positions of gold markers placed in the lung phantom were detected successfully, even for phantom velocities substantially higher than those observed for typical lung tumors. This study shows that using EPID-based marker tracking for 4D radiotherapy is feasible, however, changes in linear accelerator technology and EPID-based image acquisition as well as patient studies are required before this method can be implemented clinically. 相似文献
4.
Ford EC Chang J Mueller K Sidhu K Todor D Mageras G Yorke E Ling CC Amols H 《Medical physics》2002,29(12):2913-2924
We investigate the potential of megavoltage (MV) cone-beam CT with an amorphous silicon electronic portal imaging device (EPID) as a tool for patient position verification and tumor/organ motion studies in radiation treatment of lung tumors. We acquire 25 to 200 projection images using a 22 x 29 cm EPID. The acquisition is automatic and requires 7 minutes for 100 projections; it can be synchronized with respiratory gating. From these images, volumetric reconstruction is accomplished with a filtered backprojection in the cone-beam geometry. Several important prereconstruction image corrections, such as detector sag, must be applied. Tests with a contrast phantom indicate that differences in electron density of 2% can be detected with 100 projections, 200 cGy total dose. The contrast-to-noise ratio improves as the number of projections is increased. With 50 projections (100 cGy), high contrast objects are visible, and as few as 25 projections yield images with discernible features. We identify a technique of acquiring projection images with conformal beam apertures, shaped by a multileaf collimator, to reduce the dose to surrounding normal tissue. Tests of this technique on an anthropomorphic phantom demonstrate that a gross tumor volume in the lung can be accurately localized in three dimensions with scans using 88 monitor units. As such, conformal megavoltage cone-beam CT can provide three-dimensional imaging of lung tumors and may be used, for example, in verifying respiratory gated treatments. 相似文献
5.
Enhancing vagal tone by delivering electrical stimulation to the vagal nerves (VNS) is emerging as a promising novel therapy
in heart failure. In addition, VNS is already an FDA-approved therapy for refractory epilepsy and depression. Besides its
well-known negative chronotropic, inotropic, and dromotropic effects, VNS has profound effects on cardiac electrophysiology
and arrhythmogenesis. This review summarizes current knowledge about the complex relationship between VNS and cardiac arrhythmias.
Specifically, the focus is on VNS capability to become a therapeutic strategy along with important electrophysiological alterations
that may constitute a potential arrhythmogenic substrate and become a clinical concern. 相似文献
6.
Atanaska Marinova‐Petkova Georgi Georgiev Todor Petkov Daniel Darnell John Franks Ghazi Kayali David Walker Patrick Seiler Angela Danner Allison Graham Pamela McKenzie Scott Krauss Richard J. Webby Robert G. Webster 《Influenza and other respiratory viruses》2016,10(2):98-108
Objectives
Ducks can shed and spread influenza A viruses (IAVs) while showing no disease signs. Our objective was to clarify the role of ‘foie gras’ ducks in the circulation of IAVs in Bulgaria.Methods
Monthly avian influenza surveillance was conducted on 63 ‘foie gras’ duck farms, 52 of which were surveyed throughout the study between November 2008 and April 2012. Virologic and serologic samples were collected and tested. During this time, wild bird samples were collected at major wild bird‐resting areas near the Black Sea coast and Danube River.Results
The study showed high isolation frequency of low‐pathogenicity avian influenza viruses. In the raising population (<75 days old), subtypes H3, H4, and H6 were detected monthly and H5 LPAIV, sporadically. Different subtypes (H1, H10, H11) were isolated from the fattening premises (75‐ to 100‐day‐old ducks), suggesting different routes of introduction. Only 6 of the 52 farms that were surveyed both virologically and serologically were influenza‐free throughout the study, possibly due to higher biosecurity measures implemented. No evidence of direct transmission of IAV from wild birds was found. Wild bird surveillance showed low isolation frequency of IAV. IAV prevalence of 0·55% for migratory ducks and 0·53% for migratory geese was estimated in November–December 2011 and January–February 2012, respectively, at two ornithologically important locations near the Black Sea coast.Conclusions
The ‘foie gras’ duck farms in Bulgaria are an optimal niche where Eurasian‐like IAVs are maintained and reassorted unapparent to farmers and veterinarians. 相似文献7.
8.
Background: We previously showed that mitochondrial respiratory function is abnormal in dogs with chronic heart failure (HF). Mitochondrial
permeability transition pores (MPTP) can affect mitochondrial inner membrane potential (Δ < eqid1 > m) and mitochondrial function in normal cardiomyocytes. The potential impact of MPTP on Δ < eqid2 > m and mitochondrial respiratory function in HF has not yet been determined. We tested the hypothesis that cyclosporine A, a
potent blocker of the MPTP, can improve mitochondrial function in HF. Methods: Cardiomyocytes were isolated from the left ventricular myocardium of 7 dogs with HF produced by intracoronary microembolizations
and from 7 normal dogs. Cardiomyocytes were treated for 24 hours with cyclosporine A. Δ < eqid3 > m, cytochrome c oxidase protein expression, mitochondrial cytochrome c oxidase-dependent respiration (CDOR) and ATP synthesis
were measured. Results: Δ < eqid4 > m, protein expression of cytochrome c oxidase, CDOR and the rate of ATP synthesis were decreased in HF compared to normal controls.
Inhibition of MPTP in failing cardiomyocytes with low dose of cyclosporine A (0.2 μM) increased Δ < eqid5 > m, preserved expression of cytochrome c oxidase, improved CDOR and the rate of ATP synthesis. Conclusion: MPTP opening contributes to the loss of mitochondrial function observed in the failing heart. Inhibition of MPTP opening
represents a potential therapeutic target for the treatment of HF.
This study was supported by a grant from the National Heart, Lung, and Blood Institute PO1 HL074237-01. 相似文献
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10.
Selective silencing of DNA-specific B lymphocytes delays lupus activity in MRL/lpr mice 总被引:1,自引:0,他引:1
Tchorbanov AI Voynova EN Mihaylova NM Todorov TA Nikolova M Yomtova VM Chiang BL Vassilev TL 《European journal of immunology》2007,37(12):3587-3596
The pathological DNA-specific B lymphocytes in lupus are logical targets for a selected therapeutic intervention. We have hypothesized that it should be possible to suppress selectively the activity of these B cells in lupus mice by administering to them an artificial molecule that cross-links their surface immunoglobulins with the inhibitory FcgammaIIb surface receptors. A hybrid molecule was constructed by coupling the DNA-mimicking DWEYSVWLSN peptide to a monoclonal anti-mouse FcgammaRIIb antibody. This chimeric antibody was added to cultured spleen cells from sick MRL/lpr mice, immunized with diphtheria toxoid, resulting in reduction of the numbers of anti-DNA but not of anti-diphtheria IgG antibody-producing cells. Intravenous infusions with the DNA-peptide antibody chimera to 7-wk-old animals prevented the appearance of IgG anti-DNA antibodies and of albuminuria in the next 2 months. The administration of the DNA-peptide chimeric antibody to 18 wk-old mice with full-blown disease resulted in the maintenance of a flat level of IgG anti-DNA antibodies and in delay of the aggravation of the lupus glomerulonephritis. The use of chimeric antibodies targeting inhibitory B lymphocyte receptors represents a novel approach for the selective suppression of autoreactive disease-associated B cells in autoimmune diseases. 相似文献