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  • 1
    Online Resource
    Online Resource
    IOP Publishing ; 2015
    In:  Physics in Medicine and Biology Vol. 60, No. 16 ( 2015-08-21), p. 6323-6354
    In: Physics in Medicine and Biology, IOP Publishing, Vol. 60, No. 16 ( 2015-08-21), p. 6323-6354
    Type of Medium: Online Resource
    ISSN: 0031-9155 , 1361-6560
    RVK:
    Language: Unknown
    Publisher: IOP Publishing
    Publication Date: 2015
    detail.hit.zdb_id: 1473501-5
    SSG: 12
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  • 2
    In: Medical Physics, Wiley, Vol. 44, No. 8 ( 2017-08), p. 3965-3977
    Abstract: Dual‐energy contrast‐enhanced imaging is being investigated as a tool to identify and localize angiogenesis in the breast, a possible indicator of malignant tumors. This imaging technique requires that x‐ray images are acquired at energies above the k ‐shell binding energy of an appropriate radiocontrast agent. Iodinated contrast agents are commonly used for vascular imaging, and require x‐ray energies greater than 33 keV. Conventional direct conversion amorphous selenium ( a ‐Se) flat‐panel imagers for digital mammography show suboptimal absorption efficiencies at these higher energies. Methods We use spatial‐frequency domain image quality metrics to evaluate the performance of a prototype direct conversion flat‐panel imager with a thicker a ‐Se layer, specifically fabricated for dual‐energy contrast‐enhanced breast imaging. Imaging performance was evaluated in a prototype digital breast tomosynthesis (DBT) system. The spatial resolution, noise characteristics, detective quantum efficiency, and temporal performance of the detector were evaluated for dual‐energy imaging for both conventional full‐field digital mammography (FFDM) and DBT. Results The zero‐frequency detective quantum efficiency of the prototype detector is improved by approximately 20% over the conventional detector for higher energy beams required for imaging with iodinated contrast agents. The effect of oblique entry of x‐rays on spatial resolution does increase with increasing photoconductor thickness, specifically for the most oblique views of a DBT scan. Degradation of spatial resolution due to focal spot motion was also observed. Temporal performance was found to be comparable to conventional mammographic detectors. Conclusions Increasing the a ‐Se thickness in direct conversion flat‐panel imagers results in better performance for dual‐energy contrast‐enhanced breast imaging. The reduction in spatial resolution due to oblique entry of x‐rays is appreciable in the most extreme clinically relevant cases, but may not profoundly affect reconstructed images due to the algorithms and filters employed. Degradation to projection domain spatial resolution is thus outweighed by the improvement in detective quantum efficiency for high‐energy x‐rays.
    Type of Medium: Online Resource
    ISSN: 0094-2405 , 2473-4209
    URL: Issue
    Language: English
    Publisher: Wiley
    Publication Date: 2017
    detail.hit.zdb_id: 1466421-5
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  • 3
    In: Journal of Neurochemistry, Wiley, Vol. 80, No. 4 ( 2002-02), p. 667-677
    Abstract: Corticosteroids provide an effective treatment to reduce edema for conditions in which the blood–brain or blood–retinal barrier is compromised. However, little is known about the mechanism by which these hormones affect endothelial cell function. We hypothesized that hydrocortisone would reduce transport of water and solutes across bovine retinal endothelial cell (BREC) monolayers coincident with changes to the tight junction protein occludin. Treatment of BREC with 103 n m hydrocortisone for two days significantly decreased water and solute transport across cell monolayers. Immunoblot analysis of occludin extracted in SDS or urea based buffers revealed a 1.65‐ or 2.57‐fold increase in content, respectively. A similar two‐fold increase in occludin mRNA was observed by real‐time PCR. Immunocytochemistry revealed hydrocortisone dramatically increased both occludin and ZO‐1 staining at the cell border. Additionally, 4 h of hydrocortisone treatment significantly reduced occludin phosphorylation. To our knowledge, this is the first example of a regulated decrease in occludin phosphorylation associated with increased barrier properties. In conclusion, hydrocortisone directly affects retinal endothelial cell barrier properties coincident with changes in occludin content, phosphorylation and tight junction assembly. Localized hydrocortisone therapy may be developed as a treatment option for patients suffering from retinal edema due to diabetes.
    Type of Medium: Online Resource
    ISSN: 0022-3042 , 1471-4159
    Language: English
    Publisher: Wiley
    Publication Date: 2002
    detail.hit.zdb_id: 2020528-4
    SSG: 12
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  • 4
    Online Resource
    Online Resource
    Elsevier BV ; 2004
    In:  Microvascular Research Vol. 68, No. 3 ( 2004-11), p. 295-302
    In: Microvascular Research, Elsevier BV, Vol. 68, No. 3 ( 2004-11), p. 295-302
    Type of Medium: Online Resource
    ISSN: 0026-2862
    RVK:
    Language: English
    Publisher: Elsevier BV
    Publication Date: 2004
    detail.hit.zdb_id: 1471172-2
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  • 5
    Online Resource
    Online Resource
    Oxford University Press (OUP) ; 2012
    In:  Environmental Entomology Vol. 41, No. 6 ( 2012-12-01), p. 1680-1686
    In: Environmental Entomology, Oxford University Press (OUP), Vol. 41, No. 6 ( 2012-12-01), p. 1680-1686
    Type of Medium: Online Resource
    ISSN: 0046-225X , 0046-225X
    Language: English
    Publisher: Oxford University Press (OUP)
    Publication Date: 2012
    detail.hit.zdb_id: 2027540-7
    SSG: 12
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  • 6
    Online Resource
    Online Resource
    Wiley ; 2017
    In:  Medical Physics Vol. 44, No. 1 ( 2017-01), p. 43-56
    In: Medical Physics, Wiley, Vol. 44, No. 1 ( 2017-01), p. 43-56
    Abstract: Contrast‐enhanced ( CE ) breast imaging involves the injection contrast agents (i.e., iodine) to increase conspicuity of malignant lesions. CE imaging may be used in conjunction with digital mammography ( DM ) or digital breast tomosynthesis ( DBT ) and has shown promise in improving diagnostic specificity. Both CE ‐ DM and CE ‐ DBT techniques require optimization as clinical diagnostic tools. Physical factors including x‐ray spectra, subtraction technique, and the signal from iodine contrast, must be considered to provide the greatest object detectability and image quality. We developed a cascaded linear system model ( CLSM ) for the optimization of CE ‐ DM and CE ‐ DBT employing dual energy ( DE ) subtraction or temporal ( TE ) subtraction. Methods We have previously developed a CLSM for DBT implemented with an a‐Se flat panel imager ( FPI ) and filtered backprojection ( FBP ) reconstruction algorithm. The model is used to track image quality metrics — modulation transfer function ( MTF ) and noise power spectrum ( NPS ) — at each stage of the imaging chain. In this study, the CLSM is extended for CE breast imaging. The effect of x‐ray spectrum (varied by changing tube potential and the filter) and DE and TE subtraction techniques on breast structural noise was measured was studied and included as a deterministic source of noise in the CLSM . From the two‐dimensional (2D) and three‐dimensional (3D) MTF and NPS , the ideal observer signal‐to‐noise ratio ( SNR ), also known as the detectability index ( d ′), may be calculated. Using d ′ as a FOM , we discuss the optimization of CE imaging for the task of iodinated contrast object detection within structured backgrounds. Results Increasing x‐ray energy was determined to decrease the magnitude of structural noise and not its correlation. By performing DE subtraction, the magnitude of the structural noise was further reduced at the expense of increased stochastic (quantum and electronic) noise. TE subtraction exhibited essentially no residual structural noise at the expense of increased quantum noise, even over that of the DE case. For DE subtraction, optimization of dose weighting to the HE view ( f h ) results in the minimization of quantum noise. Both subtraction weighting factor ( w S ub ) and the iodine contrast signal were dependent on the LE and HE x‐ray spectra. To best detect a 5 mm Gaussian lesion with 5 mg/ml of iodine within a 4 cm thick breast, it was found that the high energy ( HE ) view should be acquired with a tube potential of 47 kV p (W/Ti spectrum) and the low energy ( LE ) view with a potential of 23 kV p (W/Rh spectrum). Due to the complete removal of structural noise, TE subtraction produced much higher d ′ than DE subtraction both as a function of mean glandular dose and iodine concentration. Conclusions We have shown the effect of increasing x‐ray energy as well as projection domain subtraction on breast structural noise. Further, we have exhibited the utility of the CLSM for DE and TE subtraction CE imaging in the optimization of imaging parameters such as x‐ray energy, f h , and w S ub as well as guiding the understanding of their effects on image contrast and noise.
    Type of Medium: Online Resource
    ISSN: 0094-2405 , 2473-4209
    URL: Issue
    Language: English
    Publisher: Wiley
    Publication Date: 2017
    detail.hit.zdb_id: 1466421-5
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  • 7
    Online Resource
    Online Resource
    American Physiological Society ; 2004
    In:  American Journal of Physiology-Heart and Circulatory Physiology Vol. 286, No. 2 ( 2004-02), p. H731-H741
    In: American Journal of Physiology-Heart and Circulatory Physiology, American Physiological Society, Vol. 286, No. 2 ( 2004-02), p. H731-H741
    Abstract: A sudden increase in the transmural pressure gradient across endothelial monolayers reduces hydraulic conductivity ( L p ), a phenomenon known as the sealing effect. To further characterize this endothelial adaptive response, we measured bovine aortic endothelial cell (BAEC) permeability to albumin and 70-kDa dextran, L p , and the solvent-drag reflection coefficients (σ) during the sealing process. The diffusional permeability coefficients for albumin (1.33 ± 0.18 × 10 –6 cm/s) and dextran (0.60 ± 0.16 × 10 –6 cm/s) were measured before pressure application. The effective permeabilities (measured when solvent drag contributes to solute transport) of albumin and dextran ( P ealb and P edex ) were measured after the application of a 10 cmH 2 O pressure gradient; during the first 2 h of pressure application, P ealb , P edex , and L p were significantly reduced by 2.0 ± 0.3-, 2.1 ± 0.3-, and 3.7 ± 0.3-fold, respectively. Immunostaining of the tight junction (TJ) protein zonula occludens-1 (ZO-1) was significantly increased at cell-cell contacts after the application of transmural pressure. Cytochalasin D treatment significantly elevated transport but did not inhibit the adaptive response, whereas colchicine treatment had no effect on diffusive permeability but inhibited the adaptive response. Neither cytoskeletal inhibitor altered σ despite significantly elevating both L p and effective permeability. Our data suggest that BAECs actively adapt to elevated transmural pressure by mobilizing ZO-1 to intercellular junctions via microtubules. A mechanical (passive) component of the sealing effect appears to reduce the size of a small pore system that allows the transport of water but not dextran or albumin. Furthermore, the structures of the TJ determine transport rates but do not define the selectivity of the monolayer to solutes (σ).
    Type of Medium: Online Resource
    ISSN: 0363-6135 , 1522-1539
    RVK:
    Language: English
    Publisher: American Physiological Society
    Publication Date: 2004
    detail.hit.zdb_id: 1477308-9
    SSG: 12
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  • 8
    In: Brain Imaging and Behavior, Springer Science and Business Media LLC, Vol. 4, No. 2 ( 2010-6), p. 189-197
    Type of Medium: Online Resource
    ISSN: 1931-7557 , 1931-7565
    Language: English
    Publisher: Springer Science and Business Media LLC
    Publication Date: 2010
    detail.hit.zdb_id: 2377165-3
    SSG: 5,2
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  • 9
    Online Resource
    Online Resource
    American Association for Cancer Research (AACR) ; 2016
    In:  Cancer Research Vol. 76, No. 14_Supplement ( 2016-07-15), p. 2481A-2481A
    In: Cancer Research, American Association for Cancer Research (AACR), Vol. 76, No. 14_Supplement ( 2016-07-15), p. 2481A-2481A
    Abstract: Introduction The chemically modified curcumin, CMC 2.24 (TRB-N0224, Traverse Biosciences Inc.), was designed to overcome the poor solubility, bioavailability, and biological potency of naturally occurring curcumin in an effort to achieve superior safety and efficacy in chronic inflammatory conditions and cancer. It has been demonstrated that CMC 2.24 can sensitize cancer cells that are otherwise refractory to chemotherapy. Patients with neuroblastoma, a highly lethal childhood cancer of the peripheral sympathetic nervous system, often have de novo chemotherapy resistance and therefore succumb rapidly to their disease. We hypothesize that chemoresistance in primary refractory neuroblastoma is mediated by anti-apoptotic mechanisms that can be overcome when conventional therapy is combined with CMC 2.24. Experimental Procedures A heterogeneous panel of neuroblastoma cell lines was cultured under routine conditions and subjected to varying concentrations of CMC 2.24 to establish IC50s. Subsequent studies were focused on NB-EBc1, a MYCN non-amplified cell line, and IMR-5, a MYCN amplified cell line. IC50s were also generated for cisplatin as a single agent, and then when administered in combination with CMC 2.24. Whole protein cell lysates were extracted at 24, 48, and 72 hours after treatment and cell viability was measured by MTT proliferation assays. Results Proliferation defects were observed in all neuroblastoma cell lines treated with CMC 2.24 as compared to vehicle (DMSO) control. Relatively cisplatin-resistant cell lines had diminished cell viability when CMC 2.24 was added in combination with cisplatin, suggesting a synergistic effect. Alterations in response to CMC 2.24 treatment occur in anti-apoptotic proteins survivin and BARD1, found to be upregulated in chemoresistant cell lines. Additional mechanistic evaluation is ongoing. Conclusions There is no known curative therapy for patients with primary refractory neuroblastoma. CMC 2.24 enhances chemosensitivity in a panel of neuroblastoma cell lines and may provide a new therapeutic approach that can overcome de novo chemotherapy resistance. Further mechanistic and in vivo studies are needed to facilitate clinical development of a promising novel anti-cancer agent. Citation Format: David Tauber, Basia Galinski, Raquel Castellanos, Joseph Scaduto, Francis Johnson, Lorne Golub, Daniel A. Weiser. A novel chemically-modified curcumin (CMC 2.24) promotes chemosensitivity in neuroblastoma. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 2481A.
    Type of Medium: Online Resource
    ISSN: 0008-5472 , 1538-7445
    RVK:
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    Language: English
    Publisher: American Association for Cancer Research (AACR)
    Publication Date: 2016
    detail.hit.zdb_id: 2036785-5
    detail.hit.zdb_id: 1432-1
    detail.hit.zdb_id: 410466-3
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