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Wu A, Drummond GB. Respiratory muscle activity and respiratory obstruction after abdominal surgery. Br J Anaesth 2006; 96:510-5. [PMID: 16490761 DOI: 10.1093/bja/ael035] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND Respiratory movements in patients after abdominal surgery are frequently abnormal, with associated disturbances in the pattern of inspiratory pressure generation. The reasons for these abnormalities are not clear and have been attributed to impaired action of the diaphragm. However, an alternative is that partial airway obstruction could trigger reflex activation of the inspiratory ribcage muscles, which would cause a similar pattern of inspiratory pressure change. Direct measurement of electrical activity can indicate if reflex activation of inspiratory muscles occurs when partial airway obstruction is present. METHODS In an open study, we implanted electrodes to measure the EMG of scalene, intercostal and external oblique abdominal muscles in patients after lower abdominal surgery. Analgesia was with morphine i.v. by patient control. We used nasal cannulae to measure nasal airflow and compared EMG activity when airway obstruction was present with activity when breathing was not obstructed. RESULTS The pattern of activity of the different muscles was distinct. Intercostal activity reached a maximum during inspiration, before the scalene muscles, whereas scalene activity increased in phase with increasing lung volume. Abdominal muscle activity commenced when expiratory flow had ceased and continued until the next inspiration. In all three muscle groups, partial airway obstruction did not alter muscle activity. CONCLUSIONS Partial airway obstruction does not activate inspiratory ribcage muscles, in patients receiving morphine for postoperative analgesia after lower abdominal surgery. Changes in respiratory pressures and abnormalities of chest wall movement described in previous studies cannot be attributed to reflex responses and probably result from increased airway resistance and abdominal muscle action.
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Vaynman S, Ying Z, Wu A, Gomez-Pinilla F. Coupling energy metabolism with a mechanism to support brain-derived neurotrophic factor-mediated synaptic plasticity. Neuroscience 2006; 139:1221-34. [PMID: 16580138 DOI: 10.1016/j.neuroscience.2006.01.062] [Citation(s) in RCA: 105] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2005] [Revised: 01/19/2006] [Accepted: 01/26/2006] [Indexed: 10/24/2022]
Abstract
Synaptic plasticity and behaviors are likely dependent on the capacity of neurons to meet the energy demands imposed by neuronal activity. We used physical activity, a paradigm intrinsically associated with energy consumption/expenditure and cognitive enhancement, to study how energy metabolism interacts with the substrates for neuroplasticity. We found that in an area critical for learning and memory, the hippocampus, exercise modified aspects of energy metabolism by decreasing oxidative stress and increasing the levels of cytochrome c oxidase-II, a specific component of mitochondrial machinery. We infused 1,25-dihydroxyvitamin D3, a modulator of energy metabolism, directly into the hippocampus during 3 days of voluntary wheel running and measured its effects on brain-derived neurotrophic factor-mediated synaptic plasticity. Brain-derived neurotrophic factor is a central player for the effects of exercise on synaptic and cognitive plasticity. We found that 25-dihydroxyvitamin D3 decreased exercise-induced brain-derived neurotrophic factor but had no significant effect on neurotrophin-3 levels, thereby suggesting a level of specificity for brain-derived neurotrophic factor in the hippocampus. 25-Dihydroxyvitamin D3 injection also abolished the effects of exercise on the consummate end-products of brain-derived neurotrophic factor action, i.e. cyclic AMP response element-binding protein and synapsin I, and modulated phosphorylated calmodulin protein kinase II, a signal transduction cascade downstream to brain-derived neurotrophic factor action that is important for learning and memory. We also found that exercise significantly increased the expression of the mitochondrial uncoupling protein 2, an energy-balancing factor concerned with ATP production and free radical management. Our results reveal a fundamental mechanism by which key elements of energy metabolism may modulate the substrates of hippocampal synaptic plasticity.
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Yu CM, Wong RSM, Wu EB, Kong SL, Wong J, Yip GWK, Soo YOY, Chiu MLS, Chan YS, Hui D, Lee N, Wu A, Leung CB, Sung JJY. Cardiovascular complications of severe acute respiratory syndrome. Postgrad Med J 2006; 82:140-4. [PMID: 16461478 PMCID: PMC2596695 DOI: 10.1136/pgmj.2005.037515] [Citation(s) in RCA: 242] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
BACKGROUND AND AIMS Severe acute respiratory syndrome (SARS) is a virulent viral infection that affects a number of organs and systems. This study examined if SARS may result in cardiovascular complications. METHODS AND RESULTS 121 patients (37.5 (SD13.2) years, 36% male) diagnosed to have SARS were assessed continuously for blood pressure, pulse, and temperature during their stay in hospital. Hypotension occurred in 61 (50.4%) patients in hospital, and was found in 28.1%, 21.5%, and 14.8% of patients during the first, second, and third week, respectively. Only one patient who had transient echocardiographic evidence of impaired left ventricular systolic function required temporary inotropic support. Tachycardia was present in 87 (71.9%) patients, and was found in 62.8%, 45.4%, and 35.5% of patients from the first to third week. It occurred independent of hypotension, and could not be explained by the presence of fever. Tachycardia was also present in 38.8% of patients at follow up. Bradycardia only occurred in 18 (14.9%) patients as a transient event. Reversible cardiomegaly was reported in 13 (10.7%) patients, but without clinical evidence of heart failure. Transient atrial fibrillation was present in one patient. Corticosteroid therapy was weakly associated with tachycardia during the second (chi(2) = 3.99, p = 0.046) and third week (chi(2) = 6.53, p = 0.01), although it could not explain tachycardia during follow up. CONCLUSIONS In patients with SARS, cardiovascular complications including hypotension and tachycardia were common but usually self limiting. Bradycardia and cardiomegaly were less common, while cardiac arrhythmia was rare. However, only tachycardia persisted even when corticosteroid therapy was withdrawn.
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Bhatnagar AK, Heron DE, Deutsch M, Brandner E, Wu A, Kalnicki S. Does breast size affect the scatter dose to the ipsilateral lung, heart, or contralateral breast in primary breast irradiation using intensity-modulated radiation therapy (IMRT)? Am J Clin Oncol 2006; 29:80-4. [PMID: 16462508 DOI: 10.1097/01.coc.0000198743.80991.15] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
PURPOSE To evaluate the relationship between the primary breast volume and dose received by the ipsilateral lung, heart (for left-breast cancers), and contralateral breast during primary breast irradiation using intensity-modulated radiation therapy (IMRT). METHODS AND MATERIALS Sixty-five patients with breast carcinoma were treated using 6-MV photons with IMRT technique using the Eclipse Planning System following breast conserving surgery. All patients had a treatment planning CT scan. The primary breast, ipsilateral lung, and heart were contoured on the axial CT slices. The primary breast volume was calculated using the Eclipse Planning System. The mean ipsilateral lung and heart doses were obtained from the dose-volume histogram. The contralateral breast dose was measured using paired thermoluminescent dosimeters (TLDs) placed on the patient's contralateral breast, 4 cm from the center of the medial border of the primary breast irradiation field. RESULTS The mean dose delivered with photons to the primary breast for all patients was 49.97 Gy. The mean volume of the primary irradiated breast was 1167.9 cc. As a percentage, the mean ipsilateral lung, heart, and contralateral breast doses were 11.2%, 6.1%, and 7.2%, respectively. The primary breast volume positively correlated with the contralateral breast dose (P < 0.0005). There was no significant correlation between the breast volume and the ipsilateral lung or heart dose (P = 0.463 and 0.943, respectively). CONCLUSION This study suggests that the primary breast size significantly affects the scatter dose to the contralateral breast but not the ipsilateral lung or heart dose when using IMRT for breast irradiation.
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Wang H, Lin X, Hao C, Zhang C, Sun B, Zheng J, Chen P, Sheng J, Wu A, Zhong N. A double-blind, placebo-controlled study of house dust mite immunotherapy in Chinese asthmatic patients. Allergy 2006; 61:191-7. [PMID: 16409195 DOI: 10.1111/j.1398-9995.2005.00913.x] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
BACKGROUND The purpose of this study was to determine if house dust mite immunotherapy with Alutard SQ is effective in improving symptom control and reducing rescue medication use in Chinese patients with mild to moderate allergic asthma. METHODS This is a double-blind, placebo-controlled study involving 132 asthmatic subjects aged 6-45 years recruited from three different regions of Mainland China. Subjects were given a 52-week course of immunotherapy with Dermatophagoides pteronyssinus extract (Alutard Der p, ALK-Abelló, Hørsholm, Denmark) or placebo while their dose of inhaled corticosteroids (ICS) was maintained. RESULTS 129 subjects (64 in active group) completed the study. The symptom scores began to diverge at week 29 with the immunotherapy group showing a significantly lower score until week 48 (P = 0.018). Immunotherapy resulted in a significant decline in symptom (P = 0.002) and medication (P = 0.007) scores during the second half of the treatment period. Both groups showed significant improvement in peak flow rate and bronchial hyperresponsiveness. Serum eosinophil cationic protein (ECP) also decreased in both groups of subjects, but peripheral blood eosinophil count remained unchanged. Skin test response decreased in actively treated subjects only, but Der p-specific immunoglobulin E (IgE) remained unchanged. Immunotherapy resulted in a significantly greater improvement in self-evaluation scores (P < 0.01). CONCLUSIONS One year treatment with Alutard SQ house dust mite immunotherapy significantly reduced symptoms and medication use in asthmatic subjects. This was associated with a greater subjective improvement in asthma control.
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Irvine SA, Afzal F, Meng QH, Ho J, Wu A, McEwan JR, Hart SL. 540. Genetic Intervention towards Improving the Long Term Outcome of CABG Using a Lipid Peptide DNA Vector System. Mol Ther 2006. [DOI: 10.1016/j.ymthe.2006.08.611] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022] Open
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Tang C, Wu A, Leong E, Fears T, Azzi R, O'Shannessy D, Lin A. Detection, Analysis and Significance of Guanylyl Cyclase C in the Lymph Nodes from Patients with Colorectal Cancer. J Investig Med 2006. [DOI: 10.1177/108155890605401s155] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
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Tang C, Wu A, Leong E, Fears T, Azzi R, O'Shannessy D, Lin A. 272 DETECTION, ANALYSIS AND SIGNIFICANCE OF GUANYLYL CYCLASE C IN THE LYMPH NODES FROM PATIENTS WITH COLORECTAL CANCER. J Investig Med 2006. [DOI: 10.2310/6650.2005.x0004.271] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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Fregni F, Simon DK, Wu A, Pascual-Leone A. Non-invasive brain stimulation for Parkinson's disease: a systematic review and meta-analysis of the literature. J Neurol Neurosurg Psychiatry 2005; 76:1614-23. [PMID: 16291882 PMCID: PMC1739437 DOI: 10.1136/jnnp.2005.069849] [Citation(s) in RCA: 164] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
A systematic review and meta-analysis were conducted to quantify the efficacy of transcranial magnetic stimulation (TMS) and electroconvulsive therapy (ECT) for the treatment of motor dysfunction in patients with Parkinson's disease (PD). Prospective studies which evaluated the effects of either TMS (12 studies) or ECT (five studies) on motor function in PD using the motor subscale of the Unified Parkinson's Disease Rating Scale (UPDRS) for TMS studies and any continuous measures of motor function in PD for ECT studies were included. The pooled effect size (standardised mean difference between pre-treatment versus post-treatment means) from a random effects model was 0.62 (95% confidence interval: 0.38, 0.85) for TMS treatment and 1.68 (0.79, 2.56) for ECT treatment, and from a fixed effects model was 0.59 (0.39, 0.78) for TMS treatment and 1.55 (1.07, 2.03) for ECT treatment. TMS, across applied stimulation sites and parameters, can exert a significant, albeit modest, positive effect on the motor function of patients with PD. ECT also may exert a significant effect on motor function in PD patients.
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Bhatnagar AK, Brandner E, Sonnik D, Wu A, Kalnicki S, Deutsch M, Heron DE. Intensity modulated radiation therapy (IMRT) reduces the dose to the contralateral breast when compared to conventional tangential fields for primary breast irradiation. Breast Cancer Res Treat 2005; 96:41-6. [PMID: 16244787 DOI: 10.1007/s10549-005-9032-8] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2005] [Accepted: 07/12/2005] [Indexed: 01/18/2023]
Abstract
PURPOSE To determine the dose received by the contralateral breast during primary breast irradiation using IMRT compared to conventional tangential field techniques. METHODS AND MATERIALS Between March 2003 and March 2004, 83 patients with breast carcinoma were treated using 6, 10, or mixed 6/18 MV photons (65 with tangential IMRT technique and 18 with 3-dimensional technique using tangential fields with wedges) for primary breast irradiation following breast-conserving surgery. Paired thermoluminescent dosimeters (TLDs) were placed on each patient's contralateral breast, 4 and 8 cm from the center of the medial border of the tangential field. The TLDs were left on the patient during a single fraction and then measured 24 h afterwards. RESULTS The mean dose delivered with photons to the primary breast for all patients was 4999 cGy (SD = 52) with a mean single fraction dose of 199 cGy (SD = 8). The mean percent of the prescribed dose to the contralateral breast measured at the 4- and 8-cm positions were 7.19% (SD = 2.28) and 4.63% (SD = 2.12), respectively, for patients treated with IMRT compared to 11.22% (SD = 2.73) and 10.70% (SD = 3.44), respectively, for the patients treated with conventional tangential field techniques. This represented a 36% and 57% reduction at the 4 and 8-cm contralateral positions, respectively, in the mean dose to the contralateral breast using IMRT compared to 3-D technique which was statistically significant (p < 0.0005, <0.0005, respectively). CONCLUSION Primary breast irradiation with tangential IMRT technique significantly reduces the dose to the contralateral breast compared to conventional tangential field techniques.
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Lin PS, Wu A. Not all 2 gray radiation prescriptions are equivalent: Cytotoxic effect depends on delivery sequences of partial fractionated doses. Int J Radiat Oncol Biol Phys 2005; 63:536-44. [PMID: 16168846 DOI: 10.1016/j.ijrobp.2005.06.010] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2004] [Revised: 05/27/2005] [Accepted: 06/01/2005] [Indexed: 10/25/2022]
Abstract
PURPOSE To test whether or not the commonly prescribed daily dose of 2 Gy (whole fraction), when delivered as various partial fraction (PF) dose sequences simulating clinical treatment fields, produces equal biologic effects. METHODS AND MATERIALS Eleven actively proliferating cell lines derived from human and animal tissues were used in this study. 3-(4,5-dimethylthiazol-2-yl)-2,5 diphenyltetrazolium bromide (MTT) and clonogenic assays were used to determine the radiation effects on cell proliferation and survival, respectively. The 2 Gy dose was divided into 2 or more PFs for delivery to simulate the delivery of clinical treatment fields. Most irradiation sequences contained two parts consisting of at least 1 small PF, denoted by S which was 0.5 Gy or less, and a large PF, denoted by L which was 1 Gy or more. Irradiation schemes were designed to include the following conditions: (a) the 2 Gy dose divided into combinations of an L-dose and one or more S-doses; (b) the L-dose given either before or after the S-doses; and (c) delivery of all partial fractions within a fixed total time. RESULTS Significant differences in biologic effect were observed between sequences in which the L-dose was given before or after the S-doses in both the MTT and clonogenic assays. Nearly all the latter schemes, that is S-L, produced greater cytotoxic effects than the L-S schemes. CONCLUSIONS These data demonstrate that the biologic effects of 2 Gy may differ in different clinical settings depending on the size and sequence of the partial fractions. The variation between cytotoxic effects is likely a result of the combination of low-dose hyper-radiosensitivity (HRS) and higher-dose increased radioresistance (IRR) effects established recently. We suggest that to ensure the optimal biologic effect of a prescribed dose of 2 Gy clinically, it is critical to consider the sequence in which the treatment fields are delivered when partial fractions of different sizes are used.
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DeAngelis T, Chen J, Wu A, Prisco M, Baserga R. Transformation by the simian virus 40 T antigen is regulated by IGF-I receptor and IRS-1 signaling. Oncogene 2005; 25:32-42. [PMID: 16170362 DOI: 10.1038/sj.onc.1209013] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Previous work has shown that the Simian Virus 40 T antigen (T antigen) cannot transform mouse embryo fibroblasts (MEFs) that do not express the type 1 insulin-like growth factor receptor (IGF-IR). We have now investigated the mechanism(s) by which the transforming activity of T antigen is affected by IGF-IR signaling. We demonstrate that transformation by T antigen of MEFs and several other cell lines requires an insulin receptor substrate-1 (IRS-1) phosphorylated on tyrosines. If IRS-1 is not expressed, or is serine phosphorylated or otherwise inactive, T antigen fails to transform cells in culture. For instance, while T antigen cannot transform 32D myeloid cells (that do not express IRS-1), its transforming activity is restored by the expression of a wild-type IRS-1, but not of an IRS-1 mutated at the PI3K binding sites. The importance of IRS-1 activation of PI3K in T-antigen transformation is supported by the finding that a constitutively activated p110 subunit of PI3K, a target of IRS-1, overcomes the inability of T antigen to transform MEFs with a serine phosphorylated IRS-1. Taken together, these results indicate that the IRS-1/PI3K signaling is one of the mechanisms regulating transformation by the SV40 T antigen. We propose that the requirement for a tyrosyl-phosphorylated IRS-1 provides a mechanism to explain the failure of T antigen to transform MEFs with deleted IGF-IR genes.
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MESH Headings
- Agar/chemistry
- Animals
- Antigens, Polyomavirus Transforming/chemistry
- Antigens, Polyomavirus Transforming/metabolism
- Antigens, Viral, Tumor/chemistry
- Binding Sites
- Blotting, Western
- Breast Neoplasms/metabolism
- Cell Line
- Cell Line, Transformed
- Cell Survival
- Cell Transformation, Neoplastic
- Cells, Cultured
- Fibroblasts/metabolism
- Gene Deletion
- Insulin Receptor Substrate Proteins
- Mice
- Mutation
- Neurons/metabolism
- Phosphatidylinositol 3-Kinases/metabolism
- Phosphoproteins/metabolism
- Phosphorylation
- Pol1 Transcription Initiation Complex Proteins/metabolism
- RNA/chemistry
- RNA, Ribosomal/chemistry
- Receptor, IGF Type 1/metabolism
- Ribosomes/metabolism
- Serine/chemistry
- Signal Transduction
- Time Factors
- Transfection
- Tyrosine/chemistry
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Hui ACF, Ng KC, Tong PY, Mok V, Chow KM, Wu A, Wong LKS. Bacterial meningitis in Hong Kong: 10-years’ experience. Clin Neurol Neurosurg 2005; 107:366-70. [PMID: 16023529 DOI: 10.1016/j.clineuro.2004.10.006] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2004] [Revised: 09/29/2004] [Accepted: 10/04/2004] [Indexed: 11/16/2022]
Abstract
OBJECTIVE We studied the etiology, clinical features and outcome of patients with bacterial meningitis from an urban Chinese city over a 10-years period. METHODS We reviewed the files of all persons aged 15-years old or above diagnosed with community-acquired bacterial meningitis from a regional hospital. The clinical findings, relevant laboratory and imaging results as well as outcome were recorded in cases with microbiological evidence of meningitis. Neurosurgical and pediatric patients were excluded. RESULTS Sixty-five patients between the ages of 15 and 86 years of age (mean 52 years) were identified of whom 18 (28%) died. The four most common causes were Mycobacteria tuberculosis (46%), Streptococcus pneumoniae (11%), Streptococcus suis (9%) and Klebsiella pneumoniae (8%). Neisseria meningitidis and Haemophilus influenzae were rare pathogens. The annual incidence of community-acquired bacterial meningitis was 1.27/100,000 adults. Delay in treatment was associated with a poorer prognosis (p<0.001, OR=38.84, CI=7.33-205.80). CONCLUSION The causative organisms found in this region of China differ from that reported from Europe and the US; tuberculous meningitis is the most common cause of bacterial meningitis.
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Jeon RJ, Phan TD, Wu A, Kulkarni G, Abrams SH, Mandelis A. Photothermal radiometric quantitative detection of the different degrees of demineralization of dental enamel by acid etching. ACTA ACUST UNITED AC 2005. [DOI: 10.1051/jp4:2005125165] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
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265
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Chen H, Brandner E, Wu A, Komanduri K, Shou Z. SU-FF-T-174: A New Device for the Verification of Temporal Function of the 4DCT and Gating Delivery System. Med Phys 2005. [DOI: 10.1118/1.1997845] [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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266
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Kuo H, Liu W, Chang S, Wu A, Chuang K, Lalonde R. SU-FF-T-88: Study of Merits On IMRT with Gating Technique for Treatment of Intrahepatic Cancer. Med Phys 2005. [DOI: 10.1118/1.1997759] [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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267
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Wang Z, Komanduri K, Wu A, Selvaraj R, Brandner E, Chen A, Bahri S. SU-FF-J-96: The Application of Varian's Markermatch Software in a Retrospective Study of Inter-Fractional Prostate Motion. Med Phys 2005. [DOI: 10.1118/1.1997642] [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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268
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Brandner E, Wu A, Chen H, Heron D, Komanduri K, Kalnicki S, Gerszten K, Burton S. SU-FF-J-42: Phase Lag Measurements of Abdominal Organs Relative to An External Marker Block Using Retrospective 4D CT Imaging. Med Phys 2005. [DOI: 10.1118/1.1997588] [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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269
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Kuo H, Chuang K, Wu A, Liu W, Lalonde R. SU-FF-J-109: Analysis of the Organ Motion Effects On the Fluences for Liver IMRT. Med Phys 2005. [DOI: 10.1118/1.1997655] [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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270
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Pan F, Wang P, Lee K, Wu A, Turro NJ, Koberstein JT. Photochemical modification and patterning of polymer surfaces by surface adsorption of photoactive block copolymers. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2005; 21:3605-3612. [PMID: 15807608 DOI: 10.1021/la0477439] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
We report a simple photolithographic approach for the creation and micropatterning of chemical functionality on polymer surfaces by use of surface-active block copolymers that contain protected photoactive functional groups. The block copolymers self-assemble at the substrate-air interface to generate a surface that is initially hydrophobic with low surface tension but that can be rendered hydrophilic and functional by photodeprotection with UV radiation. The block copolymer employed, poly(styrene-b-tert butyl acrylate), segregates preferentially to the surface of a polystyrene substrate because of the low surface tension of the polyacrylate blocks. The strong adsorption of block copolymers causes a bilayer structure to form presenting a photoactive polyacrylate layer at the surface. In the example described, the tert-butyl ester groups on the polyacrylate blocks are deprotected by exposure to UV radiation in the presence of added photoacid generators to form surface carboxylic acid groups. Surface micropatterns of carboxylic acid groups are generated by UV exposure through a contact mask. The success of surface chemical modification and pattern formation is demonstrated by X-ray photoelectron spectroscopy and contact angle measurements along with imaging by optical and fluorescence microscopy methods. The resultant chemically patterned surfaces are then used to template patterns of various biomolecules by means of selective adsorption, covalent bonding and molecular recognition mechanisms. The surface modification/patterning concept can be applied to virtually any polymeric substrate because protected functional groups have intrinsically low surface tensions, rendering properly designed block copolymers surface active in almost all polymeric substrates.
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Bhatnagar AK, Brandner E, Sonnik D, Wu A, Kalnicki S, Deutsch M, Heron DE. Intensity-modulated radiation therapy (IMRT) reduces the dose to the contralateral breast when compared to conventional tangential fields for primary breast irradiation: initial report. Cancer J 2005; 10:381-5. [PMID: 15701270 DOI: 10.1097/00130404-200411000-00008] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
PURPOSE This study was designed to compare the dose received by the contralateral breast during primary breast irradiation using intensity-modulated radiotherapy with the dose received via conventional tangential field techniques. METHODS/MATERIALS Between March 2003 and March 2004, 44 patients with breast carcinoma were treated using 6-, 10-, or mixed 6/18-MV photons(36 with tangential intensity-modulated radiotherapy technique and eight with three-dimensional technique using tangential fields with wedges) for primary breast irradiation after breast-conserving surgery. Paired thermoluminescent dosimeters were placed on each patient's contralateral breast, 4 cm from the center of the medial border of the tangential field. The thermoluminescent dosimeters were left on the patient during a single fraction and then measured 24 hours later. RESULTS The mean dose delivered with photons to the primary breast for all patients was 4998 cGy [SD = 52], and the mean single fraction dose was 200 cGy [SD = 9]. The mean percent of the prescribed dose to the contralateral breast was 7.74% (SD = 2.35) for patients treated with intensity-modulated radiotherapy, compared with 9.74% [SD = 2.04] for the patients treated with conventional tangential field techniques. This represented a 20% reduction in the mean dose to the contralateral breast with the use of intensity-modulated radiotherapy when compared with the dose received via the three-dimensional technique, a result that was statistically significant. CONCLUSION Primary breast irradiation with tangential intensity-modulated radiotherapy technique significantly reduces the dose to the contralateral breast when compared with conventional tangential techniques.
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Heron DE, Andrade RS, Flickinger J, Johnson J, Agarwala SS, Wu A, Kalnicki S, Avril N. Hybrid PET-CT simulation for radiation treatment planning in head-and-neck cancers: a brief technical report. Int J Radiat Oncol Biol Phys 2005; 60:1419-24. [PMID: 15590173 DOI: 10.1016/j.ijrobp.2004.05.037] [Citation(s) in RCA: 131] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2003] [Revised: 03/18/2004] [Accepted: 05/12/2004] [Indexed: 12/31/2022]
Abstract
PURPOSE To prospectively study the impact on tumor and normal tissue delineation for RT planning by use of hybrid PET-CT simulation for patients with head-and-neck cancer. METHODS AND MATERIALS Twenty-one patients were simulated in treatment position on a hybrid PET-CT scanner. Images were transferred to the Varian Eclipse planning system. Abnormal areas of fluorodeoxyglucose (FDG) uptake were contoured on PET for the gross tumor volume of primaries (GTVp) and abnormal nodal region of primaries (ABNp) then compared with the same CT gross tumor volumes (GTVc) and abnormal nodal region (ABNc). A statistical analysis was performed to evaluate the correlation of PET and CT volumes. RESULTS Positron emission tomography demonstrated the primary in all cases, whereas CT did not find the primary in 3 cases. In 8 patients, additional areas of disease were seen only in PET. The average ratio of GTVc/GTVp was 3.1 (range, 0.3-23.6), whereas for ABNc/ABNp was 0.7 (range, 0-4). Volumes for the primaries were significantly larger on CT than on PET (p = 0.002) but not for nodal regions (p = 0.5). CONCLUSIONS Hybrid PET-CT simulation is feasible and provides valuable information that results in greater delineation of normal tissues from tumor bearing areas at high risk for recurrence. This finding may further improve therapeutic window for IMRT for head-and-neck cancers.
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Brandner E, Wu A, Chen H, Heron D, Kalnicki S, Burton S. Lung tumor motion measured using retrospective 4D CT and correlated with tumor location and attachment. Int J Radiat Oncol Biol Phys 2004. [DOI: 10.1016/j.ijrobp.2004.07.082] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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Bose S, Brandner E, Selvaraj R, Bahri S, Wu A. Measurement of neutron dose for IMRT plans using 23MV photon beam. Int J Radiat Oncol Biol Phys 2004. [DOI: 10.1016/j.ijrobp.2004.07.584] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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