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Soto A, Hwang A, Stansbury J. Probing photopolymerization reactions with real-time UV/vis/near-IR spectroscopy. Dent Mater 2012. [DOI: 10.1016/j.dental.2012.07.135] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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Ma L, Sahgal A, Hwang A, Hu W, Descovich M, Chuang C, Barani I, Sneed PK, McDermott M, Larson DA. A Two-Step Optimization Method for Improving Multiple Brain Lesion Treatments with Robotic Radiosurgery. Technol Cancer Res Treat 2011; 10:331-8. [DOI: 10.7785/tcrt.2012.500210] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Planning robotic radiosurgery treatments for multiple (n > 3) metastatic brain lesions is challenging due to the need of satisfying a large number of dose-volume constraints and the requirement of prescribing different dose levels to individual targets. In this study, we developed a sequential two-step optimization technique to improve the planning quality of such treatments. In contrast to the conventional approach of where all targets are simultaneously planned, we have developed a two-step optimization method. In this method, the first step was to create treatment plans for individual targets. In the second step, the 3D dose matrices associated with each plan were exported to Dicom-RT digital files and subsequently optimized. For the optimization, a singular-value-decomposition (SVD) algorithm was implemented to minimize the dose interferences among different targets. Finally, we compared the optimized treatment plans with the treatment plans created using the conventional method to determine the effectiveness of the new method. Large improvements in target dose distributions as well as normal brain sparing were found for the two-step optimization treatment plans as compared with the conventional treatment plans. The two-step optimization significantly lowered the volume of normal brain receiving relatively low doses. For example, the normal brain volume receiving 12-Gy was reduced by averaged 42% (range 34%–47%) with the two-step optimization. Such improvements generally enlarged with increasing number of targets being treated regardless of target sizes. Of note, normal brain dose was found to increase non-linearly with increasing number of targets. In summary, a two-step optimization technique is demonstrated to significantly improve the treatment plan quality as well as reduce the planning effort for multi-target robotic radiosurgery.
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Ma L, Li K, Hwang A, Sahgal A, McDermott M, Sneed P, Larson D. SU-C-BRB-06: High-Precision Volume-Staged Treatments with Stereotactic Radiosurgery. Med Phys 2011. [DOI: 10.1118/1.3611472] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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Pomplun M, Hwang A. The Dynamics of Top-Down and Bottom-Up Control of Visual Attention during Search in Complex Scenes. J Vis 2010. [DOI: 10.1167/10.7.1275] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
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Ahmed F, Hwang A, Walsh E, Pomplun M. Conspicuity of Object Features Determines Local versus Global Mental Rotation Strategies. J Vis 2010. [DOI: 10.1167/10.7.1005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
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Hwang A, Nguyen TB, Hu W, Roach M, Gottschalk A, Pouliot J, Aubin M, Chen J. SU-GG-T-22: An Adaptive Strategy for Simultaneous Treatment of the Prostate and Pelvic Lymph Nodes. Med Phys 2010. [DOI: 10.1118/1.3468408] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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Kirby N, Chuang C, Pouliot J, Hwang A, Barani I. SU-GG-T-129: Sparing of Neural Stem Cells during Whole-Brain Radiation Treatments. Med Phys 2010. [DOI: 10.1118/1.3468518] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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Hwang A, Sneed P, Barani I, Nakamura JL, Barbaro NM, Ma L. SU-GG-T-519: Improving Gamma Knife Plans Using Independent Sector Weighting. Med Phys 2010. [DOI: 10.1118/1.3468915] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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Ma L, Sahgal A, Hwang A, Hu W, Chuang C, Descovich M, Larson DA. SU-GG-T-510: A Two-Step Optimization Technique for Planning Multi-Target Treatments with Robotic Radiotherapy. Med Phys 2010. [DOI: 10.1118/1.3468906] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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Hwang A, Pomplun M. A model of top-down control of attention during visual search in real-world scenes. J Vis 2010. [DOI: 10.1167/8.6.681] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
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Chen C, Xia P, Bui T, Kramer M, Hwang A, Schechter N, Fowble B. Atlas-based Cardiac Contours in Breast Cancer Patients Offer Efficiency, Standardization, and Comparable Spatial and Dosimetric Accuracy when Compared to Manually Generated Contours. Int J Radiat Oncol Biol Phys 2009. [DOI: 10.1016/j.ijrobp.2009.07.1414] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Smith S, Hwang A, Eichelberger J, Randell P. Reaginic Response in Rats to Alum Precipitated Antigens. Int Arch Allergy Immunol 2009. [DOI: 10.1159/000230946] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
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Tsuji S, Hwang A, Weinberg V, Yom S, Quivey J, Xia P. Adaptive IMRT for Head and Neck Cancer Based on Automatically Generated Contours using Deformable Image Registration. Int J Radiat Oncol Biol Phys 2008. [DOI: 10.1016/j.ijrobp.2008.06.508] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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Xia P, Hwang A, Ludlum E, Aubin M, Pouliot J, Roach M. TU-D-AUD B-08: Clinical Validation of a Novel Adaptive Approach for Patients Concurrently Treated with the Prostate and Pelvic Lymph Nodes. Med Phys 2008. [DOI: 10.1118/1.2962580] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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Hwang A, Mu G, Xia P. SU-GG-T-91: Decreasing IMRT Delivery Time by Accounting for Secondary Jaw Movement. Med Phys 2008. [DOI: 10.1118/1.2961843] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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Gillis A, Hwang A, Teo K, Bacharach S, Bucci M, Millender L, Schechter N, Quivey J, Franc B, Xia P. PET-CT for Head and Neck IMRT Planning: Target Delineation and Dose Escalation. Int J Radiat Oncol Biol Phys 2007. [DOI: 10.1016/j.ijrobp.2007.07.1636] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Xia P, Hwang A, Mu G, Ludlum E, Aubin M, Pouliot J, Roach III M. Multi-Adaptive-Plan (MAP) IMRT to Accommodate the Independent Movement of the Prostate and Pelvic Lymph Nodes: A Proof of Principle Study Driven by Clinical Necessity. Int J Radiat Oncol Biol Phys 2007. [DOI: 10.1016/j.ijrobp.2007.07.2118] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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Sharma S, Vogelzang N, Beck J, Patnaik A, Mita M, Dugan M, Hwang A, Culver K, Atadja P, Prince H. 702 POSTER Phase I pharmacokinetic and pharmacodynamic study of once-weekly IV LBH589. EJC Suppl 2007. [DOI: 10.1016/s1359-6349(07)70501-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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Sharma S, Vogelzang NJ, Beck J, Patnaik A, Mita M, Dugan M, Hwang A, Masson E, Culver KW, Prince H. Phase I pharmacokinetic (PK) and pharmacodynamic (PD) study of LBH589, a novel deacetylase (DAC) inhibitor given intravenously on a new once weekly schedule. J Clin Oncol 2007. [DOI: 10.1200/jco.2007.25.18_suppl.14019] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
14019 Background: LBH589 is a novel deacetylase inhibitor that inhibits proliferation of tumor cells at nanomolar levels. This phase I study tested the safety and tolerability of IV LBH589 once each week for 3 of 4 wks in pts with advanced solid tumors or lymphoma. Methods: LBH589 was administered IV over 30 min. on days 1, 8 and 15 of a 28-day cycle. Western blots on peripheral blood lymphocytes were used to study histone acetylation (HA). Plasma PK profiles were analyzed on Days 1 and 8. Results: Thirty five pts (median age: 70 yrs; 23M, 12F) have been treated on 3 dose levels [10 mg/m2 (8pts), 15 mg/m2 (8 pts), 20 mg/m2 (19 pts)] with the following tumor types: Cutaneous and peripheral T cell lymphoma (7 pts), prostate (6 pts), mesothelioma (4 pts), colon (3 pts) and other (15 pts). There was one dose-limiting toxicity (transient grade 4 thrombocytopenia) at 20 mg/m2, none at the lower doses. Other G3/G4 toxicities (all cycles) include: transient thrombocytopenia (G4–5 pts, G3–5 pts), neutropenia (G3–2 pts), anemia (G3–5 pts), G3 hypophosphatemia (1 pt), G3 hypokalemia (1 pt), G3 nausea (1 pt) and G3 pruritus (1 pt). Thrombocytopenia was transient. Of 2,042 ECGs, 1 pt had an increase in QTcF from baseline of > 60 msec another with a QTcF >500 msec, both at 20 mg/m2. There was a dose-dependent increase in HA 7 days after one dose with 43% (10 mg/m2), 50% (15 mg/m2) and 60% (20 mg/m2) of pts with increased acetylation. The LBH589 plasma conc. peaked at the end of the 0.5 hr infusion with a mean terminal half-life of 16 hr. Median Cmax achieved with 20 mg/m2 was 1,000 ng/mL (2.86 μM). The AUC0-inf increased linearly with IV doses of 10–20 mg/m2. One pt with CTCL achieved a complete response (CR) on cycle 3, Day 1; this pt had previously received oral LBH589 at 20 mg MWF, achieving a CR on cycle 6, Day 28 that lasted for 7 months. One peripheral T-Cell lymphoma pt achieved a partial response that has persisted for >7 months. One pt with prostate cancer has had a 26% reduction in nodal disease and > 50% drop in PSA in the first 2 cycles. Conclusions: The maximum tolerated dose of LBH589 given IV wkly on a 3 of 4 wk schedule is 20 mg/m2. This dose produced sustained PD effects and higher systemic exposure compared to oral LBH589. Preliminary evidence of antitumor activity has been observed. No significant financial relationships to disclose.
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Hwang A, Ludlum E, Xia P. SU-FF-T-176: Dosimetric Effects of Metallic Hip Implants On Image Guided Radiation Therapy. Med Phys 2007. [DOI: 10.1118/1.2760835] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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Hwang A, Taylor C, Seo Y, Iwata K, Li J, Patt B, Hasegawa B. WE-D-I-609-03: Improving the Quantitative Accuracy of a Dedicated Small Animal SPECT/CT Scanner. Med Phys 2005. [DOI: 10.1118/1.1998548] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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Bushey ML, Hwang A, Stephens PW, Nuckolls C. Enforced stacking in crowded arenes. J Am Chem Soc 2001; 123:8157-8. [PMID: 11506589 DOI: 10.1021/ja0104148] [Citation(s) in RCA: 100] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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48
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Hwang A, McKenna WG, Muschel RJ. Cell cycle-dependent usage of transcriptional start sites. A novel mechanism for regulation of cyclin B1. J Biol Chem 1998; 273:31505-9. [PMID: 9813064 DOI: 10.1074/jbc.273.47.31505] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Cyclin B1 mRNA is expressed temporally throughout the cell cycle with peak expression in G2 and M phase. Both transcriptional and posttranscriptional controls are important for this cell cycle-dependent regulation of cyclin B1 mRNA. In this study, we observed that cyclin B1 has two major transcripts: (a) a constitutively expressed transcript, and (b) a cell cycle-regulated transcript expressed predominantly during G2-M phase. These different transcripts are due to alternative start sites. The constitutively expressed transcript starts 65 bases upstream from the cell cycle-regulated message. Changes in mRNA stability did not appear to control the expression of the cell cycle-specific transcript, but we were able to identify a 24-base pair region of the cyclin B1 promoter spanning the start site of the cell cycle-regulated transcript that was critical for its cell cycle-regulated promoter activity. This suggests that transcriptional regulation is responsible for controlling the presence of each message. The 24-base pair sequence required for cell cycle regulation was notable for containing the nucleotides GGCT repeated three times. The possibility that these two transcripts might be physiologically distinct was raised when the cell cycle-specific transcript was found to be translated more efficiently in vitro than the constitutively expressed transcript. These results characterize a novel mechanism for the regulation of cyclin B1 throughout the cell cycle that is dependent upon the use of different transcriptional start sites.
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Hwang A, Muschel RJ. Radiation and the G2 phase of the cell cycle. Radiat Res 1998; 150:S52-9. [PMID: 9806609] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/09/2023]
Abstract
Exposure of mammalian cells to X rays results in prolongation of the cell cycle, including delays or arrests in G1, S and G2 phase. While G1-phase arrest occurs only in cells with wild-type p53 function, a G2-phase delay occurs in all cells regardless of p53 status. In this review, we summarize what is known about cell cycle progression through G2 and M phase and discuss the experimental findings that implicate different mechanisms in the G2-phase delay. Finally, we consider the possibility that G2-phase arrest plays a role in cell survival after irradiation.
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Maity A, Hwang A, Janss A, Phillips P, McKenna WG, Muschel RJ. Delayed cyclin B1 expression during the G2 arrest following DNA damage. Oncogene 1996; 13:1647-57. [PMID: 8895510] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Exposure of cells to DNA damaging agents results in a G2 arrest. Exposure of HeLa cells to camptothecin, etoposide or nitrogen mustard for 1 h in S phase resulted in delayed expression of cyclin B1 mRNA during the G2 arrest. Initially the levels of cyclin B1 protein were low as well; however, with extended time the cells blocked in G2 regained higher levels of cyclin B1 protein. In the case of cells treated with nitrogen mustard the higher levels coincided with cells exiting the G2 block into G1. However, with camptothecin or etoposide treatment, while the accumulation of cyclin B1 protein was delayed, its levels eventually surpassed peak levels seen in control cells, in spite of the fact that cells were still blocked in G2. These cells did not continue to progress through the cell cycle indicating further complexity to the mechanisms underlying the G2 block. Decreased transcription and stability of cyclin B1 mRNA were shown to occur after treatment with these DNA damaging agents. These results indicate that suppression of cyclin B1 mRNA expression is one consequence of DNA damage in HeLa cells.
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