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Alnasser SM, Moey M, Ali N, Almazroa L, Alshaibi AA, Liauw S, Claeys M, Ong G, Fam NP. Percutaneous balloon mitral valvuloplasty with shockwave lithotripsy for the treatment of calcific mitral valve stenosis. Catheter Cardiovasc Interv 2024. [PMID: 38699843 DOI: 10.1002/ccd.31063] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/10/2023] [Revised: 03/23/2024] [Accepted: 04/17/2024] [Indexed: 05/05/2024]
Abstract
BACKGROUND Calcific mitral stenosis (calcific MS) presents a challenge for surgical treatment and is a contraindication for most contemporary transcatheter mitral valve replacement devices (TMVR), rendering patients with very limited therapeutic options. AIMS This study aims to assess the clinical and hemodynamic follow-up after mitral valve lithotripsy (MVL). METHODS All consecutive patients who underwent MVL to treat symptomatic calcific MS at St Michael's Hospital, Toronto, Canada, were included. Patients were deemed unsuitable for mitral surgery or TMVR after heart team assessment. Patients with rheumatic MS or ≥moderate mitral regurgitation (MR) were excluded. The primary endpoint was a reduction in the invasive mitral gradient by ≥50% without significant (≥moderate) MR. RESULTS Fifteen patients underwent MVL between 2021 and 2023 with a mean age of 74 ± 9 years; 53% were female, with a mean STS score of 10% ± 0.1%. Following MVL, there was a reduction in the invasively measured mean trans-mitral gradient compared to baseline (14 mmHg vs. 6 mmHg; p < 0.05). The primary endpoint was achieved in 8 patients (53%) with no major procedural complications. At follow-up (median 90 days, IQR 58-115 days), 14 (93%) patients reported improved symptoms from New York Heart Association (NYHA) Class III-IV to NYHA Class I-II (p < 0.01) with stable echo-derived mean gradient (7.7 mmHg ± 2 mmHg vs. 8.4 mmHg ± 2.9 mmHg (p = 0.7). CONCLUSIONS In selected patients with symptomatic inoperable calcific MS, MVL was safe and associated with significant short-term clinical and hemodynamic improvement. MVL may represent a new compassionate therapy for this challenging cohort. Further studies are needed to determine the long-term outcomes and help define the role of IVL technology in treating calcific valvular conditions.
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Affiliation(s)
- Sami M Alnasser
- Division of Cardiology, St Michael's Hospital, University of Toronto, Ontario, Toronto, Canada
| | - Melissa Moey
- Division of Cardiology, St Michael's Hospital, University of Toronto, Ontario, Toronto, Canada
| | - Noman Ali
- Division of Cardiology, St Michael's Hospital, University of Toronto, Ontario, Toronto, Canada
| | - Loai Almazroa
- Division of Cardiology, St Michael's Hospital, University of Toronto, Ontario, Toronto, Canada
| | - Abdul-Aziz Alshaibi
- Division of Cardiology, St Michael's Hospital, University of Toronto, Ontario, Toronto, Canada
- King Abdulaziz University Hospital, Jeddah, Saudi Arabia
| | - Samantha Liauw
- Division of Cardiology, St Michael's Hospital, University of Toronto, Ontario, Toronto, Canada
| | - Mathias Claeys
- Division of Cardiology, St Michael's Hospital, University of Toronto, Ontario, Toronto, Canada
| | - Geraldine Ong
- Division of Cardiology, St Michael's Hospital, University of Toronto, Ontario, Toronto, Canada
| | - Neil P Fam
- Division of Cardiology, St Michael's Hospital, University of Toronto, Ontario, Toronto, Canada
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Ballas LK, Reddy CA, Han HR, Makar J, Mian OY, Broughman JR, de Bustamante C, Eggener S, Liauw S, Abramowitz MC, Montoya C, Tendulkar RD. Patterns of Recurrence Following Radiation and ADT for Pathologic Lymph Node Positive Prostate Cancer: A Multi-Institutional Study. Int J Radiat Oncol Biol Phys 2023; 117:e365. [PMID: 37785252 DOI: 10.1016/j.ijrobp.2023.06.2459] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/04/2023]
Abstract
PURPOSE/OBJECTIVE(S) Retrospective studies have suggested that post-operative radiation therapy (RT) can reduce the risk of cause-specific mortality in men with pathologic nodal involvement (pN1) after radical prostatectomy (RP). We evaluated prognostic factors and patterns of recurrence in patients who received post-operative RT +/- androgen deprivation therapy (ADT) for pN1 disease in a multicentric cohort of 4 academic centers. MATERIALS/METHODS Data from patients with pN1 prostate cancer after RP who subsequently received RT with short term (< = 6 mo) or long term (>6 mo) ADT were obtained from 4 academic institutions. Patterns of recurrence, biochemical progression free survival (bPFS) and distant metastasis free survival (DMFS) were evaluated. RESULTS A total of 270 patients with a median follow-up of 48 months were included. Gleason grade group (GG) 2 was present in 20 patients (7.5%), GG 3 in 81 (30%), GG4 in 36 (13.5%), GG5 in 130 (49%) patients. 256 (95%) patients had extracapsular extension, 70% had seminal vesicle invasion, 59% had positive surgical margins, and 66% had a detectable post-operative PSA. The number of positive nodes at surgery were 1 in 59%, 2 in 19% and >2 in 22% of patients. Of the 83 patients that had pre-RT imaging, 46 (55%) had a PET scan (PSMA, or fluciclovine); 25 (30%) of those had lymph nodes detected on imaging prior to RT. Median time from RP to RT was 6 mo (IQR 4.5-9.1 mo). 96% received radiation to both the prostate bed (median dose 68.4Gy) and pelvic lymph nodes (median dose 46Gy). ADT was prescribed short-term (20%) or long-term (68%), while 26 (10%) received no ADT, and 7 (3%) had an unknown duration. Biochemical failure (bF) was observed in 29% of men, with 5% having pelvic nodal failure and 11.5% having distant metastases (majority in bones, followed by paraaortic nodes) at last follow up. Of 59 patients who had normal baseline testosterone levels, 37% recovered their testosterone by last follow-up. The 4-year bRFS was 72% for all patients and was 83% for those with a pre-RT PSA of <0.1 ng/mL, 76% for PSA 0.1-<0.5 ng/mL, 60% for PSA 0.5-2 ng/mL, and 35% for PSA >2 ng/mL. On multivariable analysis, maximum pre-RT PSA ≥0.5 (0.5 to 2.0 vs <0.1 HR = 3.19; >2.0 vs <0.1 HR = 9.00), use of LTADT (HR = 0.47), and percent pN1 (HR = 1.03) were significantly associated with bF. Pre-RT PSA >2 (HR = 4.10), use of LT ADT (HR = 0.33) and percent pN1 (HR = 1.03) were also significantly associated with DM. CONCLUSION In pN1 patients, pelvic RT and ADT at low PSA levels is associated with improved oncologic outcomes compared to treatment at higher levels, suggesting that PSA may have prognostic value for pN1 prostate cancer.
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Affiliation(s)
- L K Ballas
- Department of Radiation Oncology, Cedars-Sinai Medical Center, Los Angeles, CA
| | - C A Reddy
- Department of Radiation Oncology, Taussig Cancer Institute, Cleveland Clinic, Cleveland, OH
| | - H R Han
- Jacobs School of Medicine and Biomedical Sciences, Buffalo, NY
| | - J Makar
- California University of Science and Medicine, Colton, CA
| | - O Y Mian
- Department of Radiation Oncology, Taussig Cancer Institute, Cleveland Clinic, Cleveland, OH
| | | | - C de Bustamante
- Department of Radiation and Cellular Oncology, University of Chicago Medical Center, Chicago, IL
| | - S Eggener
- Department of Surgery, University of Chicago Medical Center, Chicago, IL
| | - S Liauw
- Department of Radiation and Cellular Oncology, University of Chicago Medical Center, Chicago, IL
| | - M C Abramowitz
- Department of Radiation Oncology, University of Miami/Sylvester Comprehensive Cancer Center, Miami, FL
| | - C Montoya
- University of Miami School of Medicine, Miami, FL
| | - R D Tendulkar
- Dept of Radiation Oncology, Taussig Cancer Institute, Cleveland Clinic, Cleveland, OH
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Nguyen PL, Kollmeier MA, Rathkopf D, Hoffman KE, Zurita-Saavedra A, Spratt DE, Dess RT, Liauw S, Szmulewitz R, Einstein DJ, Bubley G, Yu JB, An Y, Wong AC, Feng FY, Mckay RR, Rose BS, Shin KY, Kibel A, Taplin MEA. FORMULA-509: A Multicenter Randomized Trial of Post-Operative Salvage Radiotherapy (SRT) and 6 Months of GnRH Agonist with Either Bicalutamide or Abiraterone Acetate/Prednisone (AAP) and Apalutamide (Apa) Post-Radical Prostatectomy (RP). Int J Radiat Oncol Biol Phys 2023; 117:S81-S82. [PMID: 37784583 DOI: 10.1016/j.ijrobp.2023.06.401] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/04/2023]
Abstract
PURPOSE/OBJECTIVE(S) FORMULA-509 was designed to evaluate whether adding six months of AAP and Apa to a GnRH Agonist could improve outcomes compared to six months of bicalutamide plus GnRH Agonist for patients with unfavorable features receiving SRT for a detectable PSA post-RP. MATERIALS/METHODS FORMULA-509 is an investigator-initiated, multi-center, open-label, randomized trial. Patients had PSA ≥0.1 post-RP and one or more unfavorable features (Gleason 8-10, PSA >0.5, pT3/T4, pN1 or radiographic N1, PSA doubling time <10 months, negative margins, persistent PSA, gross local/regional disease, or Decipher High Risk). All patients received SRT plus 6 months of GnRH agonist and randomization was to concurrent bicalutamide 50 mg or AAP 1000 mg/5 mg + Apa 240 mg QD. Radiation to pelvic nodes was required for pN1 and optional for pN0. The primary endpoint was PSA progression-free survival (PFS) and secondary endpoint was metastasis-free survival (MFS) determined by conventional imaging. The study was powered to detect a HR of 0.50 for PFS and a HR of 0.30 for MFS, each with 80% power and one-sided type I error of 0.05. Stratification was by PSA at study entry (>0.5 vs.≤0.5) and pN0 vs pN1. Analyses within these subgroups were pre-planned and utilized two-sided p-values. RESULTS Three hundred forty-five participants (332 evaluable) from 9 sites were randomized from 11/24/2017 to 3/25/2020 (172 bicalutamide, 173 AAP/Apa). Median follow-up was 34 (6-53) months; 29% were pN1 and 31% had PSA >0.5 ng/mL. The HR for PFS was 0.71 (90% CI 0.49-1.03), stratified one-sided log-rank p = 0.06 (3-year PFS was 68.5% bicalutamide vs 74.9% AAP/Apa). The HR for MFS was 0.57 (90% CI 0.33-1.01), stratified one-sided log rank p = 0.05 (3-year MFS was 87.2% bicalutamide vs 90.6% AAP/Apa). In a pre-planned analysis by stratification factors, AAP/Apa was significantly superior for patients with PSA >0.5 for PFS [HR 0.50, (95% CI 0.27-0.95), p = 0.03 (2-sided); 3-year PFS 46.8% bicalutamide vs. 67.2% AAP/Apa] and for MFS [HR 0.32 (95% CI 0.13-0.84), p = 0.02 (2-sided); 3-year MFS 66.1% bicalutamide vs. 84.3% AAP/Apa.] No statistically significant benefit was detected in pre-planned analyses of stratification subgroups defined by PSA≤0.5, pN0, or pN1. Adverse events were consistent with the known safety profiles of the agents being studied, with more rash and hypertension in the AAP/Apa arm. CONCLUSION Although this primary analysis did not meet the pre-specified threshold for statistical significance, it does strongly suggest that the addition of AAP/Apa instead of bicalutamide to SRT+6 months of GnRH Agonist may improve PFS and MFS, particularly in the subgroup of patients with PSA>0.5 where a pre-planned subgroup analysis by stratification factors observed a statistically significant benefit for both PFS and MFS. (NCT03141671).
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Affiliation(s)
- P L Nguyen
- Brigham and Women's Hospital/Dana-Farber Cancer Institute, Boston, MA
| | - M A Kollmeier
- Department of Radiation Oncology, Memorial Sloan Kettering Cancer Center, New York, NY
| | - D Rathkopf
- Department of Medicine, Memorial Sloan Kettering Cancer Center, New York, NY
| | - K E Hoffman
- Department of Breast Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX
| | | | - D E Spratt
- Department of Radiation Oncology, University Hospitals Seidman Cancer Center and Case Western Reserve University, Cleveland, OH
| | - R T Dess
- Department of Radiation Oncology, University of Michigan, Ann Arbor, MI
| | - S Liauw
- Department of Radiation and Cellular Oncology, University of Chicago Medical Center, Chicago, IL
| | | | - D J Einstein
- Beth Israel Deaconess Medical Center, Boston, MA
| | - G Bubley
- Beth Israel Deaconess Medical Center, Boston, MA
| | - J B Yu
- Saint Francis Radiation Oncology, Hartford, CT
| | - Y An
- Department of Therapeutic Radiology, Yale School of Medicine, New Haven, CT
| | - A C Wong
- University of California San Francisco, Department of Radiation Oncology, San Francisco, CA
| | - F Y Feng
- Department of Radiation Oncology, University of California San Francisco, San Francisco, CA
| | - R R Mckay
- University of California San Diego, La Jolla, CA
| | - B S Rose
- UCSD Center for Health Equity, Education, and Research, La Jolla, CA
| | - K Y Shin
- Department of Data Science, Dana-Farber Cancer Institute, Boston, MA
| | - A Kibel
- Brigham and Women's Hospital, Boston, MA
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Serra LM, Wu T, Korpics MC, Yenice KM, Liauw S. Online Correction of Intrafraction Motion during Volumetric Modulated Arc Therapy for Prostate Radiotherapy: A Cohort Study Quantifying the Frequency of Shifts and Analysis of Men at Highest Risk. Int J Radiat Oncol Biol Phys 2023; 117:e435-e436. [PMID: 37785417 DOI: 10.1016/j.ijrobp.2023.06.1606] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/04/2023]
Abstract
PURPOSE/OBJECTIVE(S) We have previously described our early experience using fiducial markers to correct for intrafraction motion during radiation therapy (RT) to the prostate using the TrueBeam Advanced imaging package. We sought to further characterize the utility of this approach in a larger cohort, and analyze factors associated with intrafraction motion. MATERIALS/METHODS A total of 132 men with fiducial markers treated with RT for intact prostate cancer at a single center were treated with a VMAT technique using 2-3 arcs. All patients underwent planning CT after a rectal enema and same day placement of 3 fiducial markers (Gold Anchor). Triggered kV images were acquired every 10 seconds using an onboard imaging system. Intrafraction motion correction was considered if any two fiducial markers were observed beyond a 3 mm tolerance margin. A manual 2D-3D match was performed using the fiducial markers from the single triggered kV image to obtain a couch shift. Shift data were extracted from the record and verify system and expressed as a single 3-dimensional translation. Shift percent was defined as the number of instances of a >3 mm intrafraction correction divided by the total number of fractions for a given patient. Clinical variables were evaluated, including body mass index, hormone therapy (ADT), prostate, rectal bladder volumes, and rectal width (transverse dimension of rectum at the mid-gland of prostate on simulation CT). RESULTS Across 2659 fractions, intrafraction motion correction was performed 582 times, in 463 fractions (17%). 101/132 patients (77%) had at least one shift during their treatment course, and 48/132 patients (36%) had shifts with an average magnitude of at least 5 mm. The median shift was 3.6 mm (range, 0-2.4 cm; IQR, 1.5-5.4 mm). 25% of men had a shift percent >20% (SP>20%). Univariate analysis revealed that only larger rectal volume or width, smaller prostate size, and use of ADT were associated with SP>20% (p<0.05). Men with rectal width in the top quartile (>3.6 cm) were more likely to have intrafraction motion corrected with SP>20% (47% vs 18%, p = 0.0016), and similarly men with rectal volume in the top quartile (>112 cc) were more likely to have SP>20% (44% vs 19%, p = 0.0067). On multivariate analysis, only rectal parameters (e.g., top quartile rectal width, HR 3.9, p = 0.0024) were correlated with a higher frequency of intrafraction motion. CONCLUSION Intrafraction motion occurs in a significant percentage of men undergoing prostate RT with VMAT, and is correctable utilizing a common feature. On multivariate analysis, rectal volume and width were associated with larger shift percent. Treatment approaches which do not account for intrafraction motion should consider including methods of immobilization, or larger PTV margins in order to avoid marginal miss of the prostate.
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Affiliation(s)
- L M Serra
- Department of Radiation and Cellular Oncology, University of Chicago Medical Center, Chicago, IL
| | - T Wu
- Department of Radiation and Cellular Oncology, University of Chicago Medical Center, Chicago, IL
| | - M C Korpics
- Department of Radiation and Cellular Oncology, University of Chicago Medical Center, Chicago, IL
| | - K M Yenice
- Department of Radiation and Cellular Oncology, University of Chicago Medical Center, Chicago, IL
| | - S Liauw
- Department of Radiation and Cellular Oncology, University of Chicago Medical Center, Chicago, IL
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Garcia S, Ye J, Webb J, Reardon M, Kleiman N, Goel S, Hatab T, Fam N, Peterson M, Liauw S, Frisoli TM, Bashir H, Paige D, Rock D, Schmidt C, Jollis JG, Kereiakes DJ. Transcatheter Treatment of Native Aortic Valve Regurgitation: The North American Experience With a Novel Device. JACC Cardiovasc Interv 2023; 16:1953-1960. [PMID: 37212431 DOI: 10.1016/j.jcin.2023.05.018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/12/2023] [Revised: 05/04/2023] [Accepted: 05/09/2023] [Indexed: 05/23/2023]
Abstract
BACKGROUND Transcatheter treatment of patients with native aortic valve regurgitation (AR) has been limited by anatomical factors. No transcatheter device has received U.S. regulatory approval for the treatment of patients with AR. OBJECTIVES The aim of this study was to describe the compassionate-use experience in North America with a dedicated transcatheter device (J-Valve). METHODS A multicenter, observational registry was assembled of compassionate-use cases of J-Valve implantation for the treatment of patients with severe symptomatic AR and elevated surgical risk in North America. The J-Valve consists of a self-expanding Nitinol frame, bovine pericardial leaflets, and a valve-locating feature. The available size matrix (5 sizes) can treat a wide range of anatomies (minimum and maximum annular perimeters 57-104 mm). RESULTS A total of 27 patients (median age 81 years [IQR: 72-85 years], 81% at high surgical risk, 96% in NYHA functional class III or IV) with native valve AR were treated with the J-Valve during the study period (2018-2022). Procedural success (J-Valve delivered to the intended location without the need for surgical conversion or a second transcatheter heart valve) was 81% (22 of 27 cases) in the overall experience and 100% in the last 15 cases. Two cases required conversion to surgery in the early experience, leading to changes in valve design. At 30 days, there was 1 death, 1 stroke, and 3 new pacemakers (13%), and 88% of patients were in NYHA functional class I or II. No patient had residual AR of moderate or greater degree at 30 days. CONCLUSIONS The J-Valve appears to provide a safe and effective alternative to surgery in patients with pure AR and elevated or prohibitive surgical risk.
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Affiliation(s)
- Santiago Garcia
- The Christ Hospital Heart and Vascular Institute and Lindner Center for Research and Education, Cincinnati, Ohio, USA.
| | - Jian Ye
- Center for Heart Valve Innovation, St. Paul's Hospital, Vancouver, British Columbia, Canada
| | - John Webb
- Center for Heart Valve Innovation, St. Paul's Hospital, Vancouver, British Columbia, Canada
| | | | | | - Sachin Goel
- Houston Methodist Hospital, Houston, Texas, USA
| | - Taha Hatab
- Houston Methodist Hospital, Houston, Texas, USA
| | - Neil Fam
- St. Michael's Hospital and University of Toronto, Toronto, Ontario, Canada
| | - Mark Peterson
- St. Michael's Hospital and University of Toronto, Toronto, Ontario, Canada
| | - Samantha Liauw
- St. Michael's Hospital and University of Toronto, Toronto, Ontario, Canada
| | | | - Hanad Bashir
- The Christ Hospital Heart and Vascular Institute and Lindner Center for Research and Education, Cincinnati, Ohio, USA
| | - Debra Paige
- The Christ Hospital Heart and Vascular Institute and Lindner Center for Research and Education, Cincinnati, Ohio, USA
| | - Darlene Rock
- The Christ Hospital Heart and Vascular Institute and Lindner Center for Research and Education, Cincinnati, Ohio, USA
| | - Christian Schmidt
- The Christ Hospital Heart and Vascular Institute and Lindner Center for Research and Education, Cincinnati, Ohio, USA
| | - James G Jollis
- The Christ Hospital Heart and Vascular Institute and Lindner Center for Research and Education, Cincinnati, Ohio, USA
| | - Dean J Kereiakes
- The Christ Hospital Heart and Vascular Institute and Lindner Center for Research and Education, Cincinnati, Ohio, USA
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Tran P, Lowe K, Wang H, Tsai H, Song D, Hung A, Hearn J, Miller S, Lotan T, DeWeese T, Orton M, Jr CD, Liauw S, Heath E, Greco S, Desai N, Spratt D, Feng F, Beer T, Antonarakis E. Phase II Randomized Study of Salvage Radiation Therapy (SRT) plus Enzalutamide or Blinded Placebo for High-Risk PSA-Recurrent Prostate Cancer after Radical Prostatectomy: The SALV-ENZA Trial. Int J Radiat Oncol Biol Phys 2022. [DOI: 10.1016/j.ijrobp.2022.07.397] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Arshad M, Al-Hallaq H, Polite B, Hyman N, Liauw S. Intra-Operative Radiation Therapy and Surgical Excision for Locally Recurrent Gastrointestinal Cancers: Initial Results of a Single-Institution Registry. Int J Radiat Oncol Biol Phys 2021. [DOI: 10.1016/j.ijrobp.2021.07.336] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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Juloori A, Liao C, Lemons J, Singh A, Iyer R, Robbins J, George B, Fung J, Pillai A, Arif F, Sharma M, Liauw S. Phase I Study of Stereotactic Body Radiotherapy followed by Ipilimumab with Nivolumab vs. Nivolumab alone in Unresectable Hepatocellular Carcinoma. Int J Radiat Oncol Biol Phys 2020. [DOI: 10.1016/j.ijrobp.2020.07.900] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Liauw S, Saibil F. Sorbitol: Often forgotten cause of osmotic diarrhea. Can Fam Physician 2019; 65:557-558. [PMID: 31413027 PMCID: PMC6693595] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Affiliation(s)
- Samantha Liauw
- Fifth-year resident in cardiology at the University of Toronto in Ontario
| | - Fred Saibil
- Professor in the Division of Gastroenterology in the Department of Medicine at Sunnybrook Health Sciences Centre and the University of Toronto.
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Ni L, Kozloff M, Wu T, Arif F, Posner M, Kindler H, Liauw S. A Phase I/II Trial of Stereotactic Body Radiation Therapy for Unresectable Pancreatic Cancer Using Ablative (BED100) Doses. Int J Radiat Oncol Biol Phys 2018. [DOI: 10.1016/j.ijrobp.2018.06.331] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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Foster B, Jackson W, Foster C, Dess R, Abu-Isa E, McLaughlin P, Merrick G, Hearn J, Spratt D, Liauw S, Hamstra D. Application of a Prognostic Stratification System for High-Risk Prostate Cancer to Patients Treated with Radiation Therapy: Implications for Treatment Optimization. Int J Radiat Oncol Biol Phys 2018. [DOI: 10.1016/j.ijrobp.2018.07.301] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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Gutiontov S, Liauw S. Improved Long-Term Outcomes after Radiation Therapy for Prostate Cancer for Men on Anticoagulation: Low Platelet Count as a Contributing Factor in Disease Recurrence. Int J Radiat Oncol Biol Phys 2018. [DOI: 10.1016/j.ijrobp.2018.07.311] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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Son C, Liauw S, Hasan Y, Solanki A. Optimizing the Role of Surgery and Radiation Therapy in Urethral Cancer Based on Histology and Disease Extent. Int J Radiat Oncol Biol Phys 2018. [DOI: 10.1016/j.ijrobp.2018.07.1748] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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Liauw S, Kauffmann G, Patel P, Oto A. Largest Axial Dimension of Tumor on T2W Endorectal MRI is Associated with Biochemical Outcome in Men Treated with External Beam Radiation Therapy for Prostate Cancer. Int J Radiat Oncol Biol Phys 2018. [DOI: 10.1016/j.ijrobp.2018.07.336] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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Akthar A, Liao C, Liauw S. A Prospective Cohort Study of Patient Reported Outcomes and Late Toxicity in Patients Receiving Post-Prostatectomy Intensity Modulated Radiation Therapy (IMRT). Int J Radiat Oncol Biol Phys 2018. [DOI: 10.1016/j.ijrobp.2018.07.376] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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Foster C, Lee A, Hart J, Alpert L, Furtado L, Xiao S, Liauw S. Long-Term Outcomes and HPV Characteristics for an Institutional Cohort of Patients With Anal Cancer Receiving Concurrent Chemotherapy and Intensity-Modulated Radiation Therapy. Int J Radiat Oncol Biol Phys 2017. [DOI: 10.1016/j.ijrobp.2017.06.954] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Hwang W, Tendulkar R, Niemierko A, Agrawal S, Stephans K, Spratt D, Hearn J, Koontz B, Lee W, Michalski J, Pisansky T, Liauw S, Abramowitz M, Pollack A, Moghanaki D, Anscher M, Den R, Zietman A, Stephenson A, Efstathiou J. Multi-institutional Outcomes of Postprostatectomy Adjuvant Versus Early Salvage Radiation Therapy in Prostate Cancer Patients With Adverse Pathologic Features. Int J Radiat Oncol Biol Phys 2017. [DOI: 10.1016/j.ijrobp.2017.06.232] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Kauffmann G, Oto A, Arif F, Liauw S. Intraprostatic Disease Burden and Extracapsular Extension by MRI May Identify Men With Intermediate-Risk Prostate Cancer Who Benefit from Combined Hormonal Therapy and Radiation. Int J Radiat Oncol Biol Phys 2017. [DOI: 10.1016/j.ijrobp.2017.06.1190] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Lee A, Golden D, Bazan J, Pelizzari C, Aggarwal S, Chang D, Liauw S. Hematologic Toxicity During Anal Cancer Treatment: The Importance of Pelvic Bone Marrow Volume and Limiting Radiation Dose to a Critical Marrow Volume. Int J Radiat Oncol Biol Phys 2016. [DOI: 10.1016/j.ijrobp.2016.06.1133] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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Agrawal S, Stephenson A, Michalski J, Efstathiou J, Pisansky T, Feng F, Hamstra D, Koontz B, Liauw S, Abramowitz M, Pollack A, Anscher M, Moghanaki D, Den R, Stephans K, Gao T, Kattan M, Tendulkar R. Prostate Cancer–Specific Mortality and Survival Outcomes for Salvage Radiation Therapy After Radical Prostatectomy. Int J Radiat Oncol Biol Phys 2016. [DOI: 10.1016/j.ijrobp.2016.06.251] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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Lee A, Thomas S, Liauw S. Using Pelvic Bone Marrow Hounsfield Units to Predict Cytopenia During Anal Cancer Chemoradiation. Int J Radiat Oncol Biol Phys 2016. [DOI: 10.1016/j.ijrobp.2016.06.1129] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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Gunther J, Liauw S, Choi S, Mohamed A, Thaker N, Fuller C, Stepaniak C, Das P, Golden D. Evaluation of Clinical Target Volume Delineation Before and After a Teaching Intervention: Creation of a Postoperative Prostate and Seminal Vesicle Fossae Contouring Module. Int J Radiat Oncol Biol Phys 2015. [DOI: 10.1016/j.ijrobp.2015.07.1499] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Kropp L, Oto A, Dess R, Liauw S. Endorectal MRI in the Initial Assessment of Prostate Cancer: Radiographic Findings and Impact on Radiotherapeutic Treatment Decisions. Int J Radiat Oncol Biol Phys 2015. [DOI: 10.1016/j.ijrobp.2015.07.1164] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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Parekh A, Son C, Melotek J, Pelizzari C, Hubert G, Liauw S. Late Toxicity After Post Prostatectomy Radiation Therapy: Evaluating RTOG 0534 Tissue-Sparing Guidelines. Int J Radiat Oncol Biol Phys 2015. [DOI: 10.1016/j.ijrobp.2015.07.1128] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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Tendulkar R, Agrawal S, Efstathiou J, Pisansky T, Michalski J, Koontz B, Hamstra D, Feng F, Liauw S, Abramowitz M, Pollack A, Anscher M, Moghanaki D, Den R, Stephans K, Kattan M, Stephenson A. Contemporary Update of a Multi-institutional Predictive Nomogram for Salvage Radiation Therapy After Prostatectomy. Int J Radiat Oncol Biol Phys 2015. [DOI: 10.1016/j.ijrobp.2015.07.313] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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Agrawal S, Pisansky T, Hamstra D, Liauw S, Koontz B, Efstathiou J, Michalski J, Feng F, Abramowitz M, Pollack A, Anscher M, Moghanaki D, Den R, Stephans K, Kattan M, Stephenson A, Tendulkar R. Dose Response for Salvage Radiation Therapy After Radical Prostatectomy in Margin-Positive Prostate Cancer. Int J Radiat Oncol Biol Phys 2015. [DOI: 10.1016/j.ijrobp.2015.07.317] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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Ying J, Yan J, Roehrborn C, Lotan Y, Xie X, Pistenmaa D, Liauw S, Kim D. Long-Term Outcome of Prostate Cancer Patients Who Fail Salvage Radiation Therapy and Radical Prostatectomy. Int J Radiat Oncol Biol Phys 2014. [DOI: 10.1016/j.ijrobp.2014.05.1284] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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Son C, Melotek J, Liao C, Hubert G, Pelizzari C, Liauw S. Bladder Dose-Volume Parameters Predict for Urinary Incontinence After Postoperative Radiation for Prostate Cancer. Int J Radiat Oncol Biol Phys 2014. [DOI: 10.1016/j.ijrobp.2014.05.1358] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Abramowitz M, Williams S, Stephenson A, Kattan M, Pisansky T, Klein E, Anscher M, Michalski J, Sandler H, Forman J, Zelefsky M, Kestin L, DeWeese T, Liauw S, Valicenti R, Kuban D, Pollack A. Defining Long Term Failure Risk in Patients With an Undetectable PSA After Salvage Radiation. Int J Radiat Oncol Biol Phys 2014. [DOI: 10.1016/j.ijrobp.2014.05.579] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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Chennupati S, Pelizzari C, Kunnavakkam R, Liauw S. Late Gastrointestinal and Genitourinary Toxicity and Quality of Life After Treatment for Localized Prostate Cancer: Redefining Optimal Rectal DVH Parameters for Intensity Modulated Radiation Therapy. Int J Radiat Oncol Biol Phys 2013. [DOI: 10.1016/j.ijrobp.2013.06.450] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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Liauw S, Stephens K. Salvage Radiation Therapy After Postprostatectomy Failure: Benefits of Hormonal Therapy and Pelvic Nodal Radiation Are Not Necessarily Limited to “High-Risk” Cases. Int J Radiat Oncol Biol Phys 2013. [DOI: 10.1016/j.ijrobp.2013.06.1025] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Offor O, Liauw S. PSA Halving Time of ≤2 Weeks and Post-RT PSA Nadir < 0.1 ng/mL are Associated With Excellent Biochemical Control for High-Risk Prostate Cancer: Implications Regarding the Need for Long-term ADT With Dose Escalated RT. Int J Radiat Oncol Biol Phys 2012. [DOI: 10.1016/j.ijrobp.2012.07.1097] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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Ranck M, Liauw S. Refining Intermediate Risk Prostate Cancer: An Analysis of Prostate Biopsy Pathology and Implications for Hormone Therapy With Dose Escalated Radiation. Int J Radiat Oncol Biol Phys 2012. [DOI: 10.1016/j.ijrobp.2012.07.1028] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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Gangadwala J, Liauw S. Anwendung der dynamischen Simulation zur Sicherheitsanalyse industrieller Kolonnen. CHEM-ING-TECH 2012. [DOI: 10.1002/cite.201250456] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Abstract
BACKGROUND It is amply documented that mood disorders adversely affect job satisfaction, workforce productivity, and absenteeism/presenteeism. It is also well documented that mood disorders are an independent risk factor for several chronic medical disorders (e.g., obesity, diabetes mellitus, cardiovascular disease). Emerging evidence indicates that the workforce dysfunction associated with depression is partially mediated by medical comorbidity. METHODS We conducted a PubMed search of all English-language articles published between 2005 and July 2009 with the following search terms: major depressive disorder and depression, cross-referenced with work productivity, disability, economic cost, absenteeism, presenteeism, and medical comorbidity. Articles selected for review were based on adequacy of sample size, the use of standardized experimental procedures, validated assessment measures, and overall manuscript quality. RESULTS Mood disorders are the most impairing condition amongst working adults. It is estimated that approximately 35-50% of employees with depression will take short-term disability leave at some point during their job tenure. Moreover, 15-20% of the workforce will receive short-term disability benefits during any given year; the annual income of individuals affected by depression is reduced by approximately 10% when compared to unaffected employees. Chronic stress-sensitive conditions independently contribute to workforce maladjustment and associated disability. The mood disorder population is differentially affected by several stress-related medical conditions resulting in greater impairment in the workforce. CONCLUSION Disability modelling in the depressed employee has emphasized the complex interrelationship between depressive symptoms, workforce stress, and consequent disability. A more refined model must include the effects of chronic medical conditions as a powerful mediator and/or moderator of workforce impairment. Multidisciplinary interventions have been demonstrated to reduce, but not eliminate workforce disability related to depression, underscoring the need for elucidating other modifiable factors. Screening, treatment, and prevention initiatives need to target chronic medical conditions in depressed employees in order to reduce overall workforce disability.
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Ali A, Rossi P, Godette K, Liauw S, Vijayakumar S, Cooper S, Jani A. Impact of MR on CT-based Treatment Planning and Acute Toxicity for Prostate Cancer Patients Treated with Intensity-modulated Radiotherapy (IMRT). Int J Radiat Oncol Biol Phys 2009. [DOI: 10.1016/j.ijrobp.2009.07.129] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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Liauw S, Stadler W, Correa D, Weichselbaum R, Jani A. Dose Escalated Radiation Therapy for High Risk Prostate Cancer: Outcomes in the Modern Era with Short Term Androgen Deprivation Therapy. Int J Radiat Oncol Biol Phys 2009. [DOI: 10.1016/j.ijrobp.2009.07.703] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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Song S, Liauw S. Image Guided Radiotherapy after Radical Prostatectomy: A Report of Total Setup Error using Surgical Clips as Fiducials. Int J Radiat Oncol Biol Phys 2009. [DOI: 10.1016/j.ijrobp.2009.07.1508] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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Wu T, Kopec M, Liauw S, Yenice K. Can SBRT of 45 Gy in 3 Fractions be Safely Delivered to Unresectable Pancreas Cancer Patients. Int J Radiat Oncol Biol Phys 2009. [DOI: 10.1016/j.ijrobp.2009.07.1548] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Jani A, Johnstone P, Liauw S, Master V, Rossi P. Prostate Cancer Modality Time Trend Analyses from 1973-2004: A Surveillance, Epidemiology, and End Results (SEER) Registry Analysis. Int J Radiat Oncol Biol Phys 2008. [DOI: 10.1016/j.ijrobp.2008.06.855] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Yeung A, Liauw S, Amdur R, Mancuso A, Hinerman R, Villaret D, Werning J, Morris C, Mendenhall W. Lymph Node-Positive Head and Neck Cancer Treated With Primary Radiotherapy: Can Treatment Response Determine the Extent of Neck Dissection? Int J Radiat Oncol Biol Phys 2007. [DOI: 10.1016/j.ijrobp.2007.07.027] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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Schwede F, Christensen A, Liauw S, Hippe T, Kopperud R, Jastorff B, Døskeland SO. 8-Substituted cAMP analogues reveal marked differences in adaptability, hydrogen bonding, and charge accommodation between homologous binding sites (AI/AII and BI/BII) in cAMP kinase I and II. Biochemistry 2000; 39:8803-12. [PMID: 10913291 DOI: 10.1021/bi000304y] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
cAMP analogues, systematically substituted at position 8 of the adenine moiety (C8), were tested quantitatively for binding to each cAMP interaction site (A and B) of the regulatory subunits of cAMP-dependent protein kinase type I (RI) and II (RII). Site AII did not accommodate cAMP analogues with any bulk at position 8, whereas site AI accepted even bulky 8-substituents. This implies that the narrow, buried pocket of site AI facing position C8 of cAMP in the RI-cAMP crystal [Su, Y., Dostmann, W. R., Herberg, F. W., Durick, K., Xuong, N. H., Ten Eyck, L., Taylor, S. S., and Varughese, K. I. (1995) Science 269, 807-813] must undergo considerable conformational change and still support high-affinity cAMP analogue binding. The B sites of RI and RII differed in three respects. First, site BI had a lower affinity than site BII for cAMP analogues with hydrophobic, bulky 8-substituents. Second, site BI had a preference for substituents with hydrogen bonding donor potential close to C8, whereas site BII had a preference for substituents with hydrogen bonding acceptor potential. This implies that Tyr(371) of RI and the homologous Tyr(379) of RII differ in their hydrogen bonding preference. Third, site BI preferred analogues with a positively charged amino group that was an extended distance from C8, whereas site BII discriminated against a positive charge. The combined results allow refinement of the cAMP binding site geometry of RI and RII in solution, and suggest design of improved isozyme-specific cAMP analogues.
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Affiliation(s)
- F Schwede
- Centre for Environmental Research and Environmental Technology, Department of Bioorganic Chemistry, University of Bremen, Germany
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Cauthron RD, Carter KB, Liauw S, Steinberg RA. Physiological phosphorylation of protein kinase A at Thr-197 is by a protein kinase A kinase. Mol Cell Biol 1998; 18:1416-23. [PMID: 9488457 PMCID: PMC108855 DOI: 10.1128/mcb.18.3.1416] [Citation(s) in RCA: 61] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Phosphorylation of the catalytic subunit of cyclic AMP-dependent protein kinase, or protein kinase A, on Thr-197 is required for optimal enzyme activity, and enzyme isolated from either animal sources or bacterial expression strains is found phosphorylated at this site. Autophosphorylation of Thr-197 occurs in Escherichia coli and in vitro but is an inefficient intermolecular reaction catalyzed primarily by active, previously phosphorylated molecules. In contrast, the Thr-197 phosphorylation of newly synthesized protein kinase A in intact S49 mouse lymphoma cells is both efficient and insensitive to activators or inhibitors of intracellular protein kinase A. Using [35S]methionine-labeled, nonphosphorylated, recombinant catalytic subunit as the substrate in a gel mobility shift assay, we have identified an activity in extracts of protein kinase A-deficient S49 cells that phosphorylates catalytic subunit on Thr-197. The protein kinase A kinase activity partially purified by anion-exchange and hydroxylapatite chromatography is an efficient catalyst of protein kinase A phosphorylation in terms of both a low Km for ATP and a rapid time course. Phosphorylation of wild-type catalytic subunit by the kinase kinase activates the subunit for binding to a pseudosubstrate peptide inhibitor of protein kinase A. By both the gel shift assay and a [gamma-32P]ATP incorporation assay, the enzyme is active on wild-type catalytic subunit and on an inactive mutant with Met substituted for Lys-72 but inactive on a mutant with Ala substituted for Thr-197. Combined with the results from mutant subunits, phosphoamino acid analysis suggests that the enzyme is specific for phosphorylation of Thr-197.
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Affiliation(s)
- R D Cauthron
- Department of Biochemistry and Molecular Biology, University of Oklahoma Health Sciences Center, Oklahoma City 73190, USA
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Liauw S, Steinberg RA. Dephosphorylation of catalytic subunit of cAMP-dependent protein kinase at Thr-197 by a cellular protein phosphatase and by purified protein phosphatase-2A. J Biol Chem 1996; 271:258-63. [PMID: 8550570 DOI: 10.1074/jbc.271.1.258] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
Thr-197 phosphate is essential for optimal activity of the catalytic (C) subunit of cAMP-dependent protein kinase enzyme, and, in the C subunit crystal structure, it is buried in a cationic pocket formed by the side chains of His-87, Arg-165, Lys-189, and Thr-195. Because of its apparent role in stabilizing the active conformation of C subunit and its resistance to several phosphatases, the phosphate on Thr-197 has been assumed to be metabolically stable. We now show that this phosphate can be removed from C subunit by a protein phosphatase activity extracted from S49 mouse lymphoma cells or by purified protein phosphatase-2A (PP-2A) with concomitant loss of enzymatic activity. By anion-exchange chromatography, inhibitor sensitivity, and relative activity against glycogen phosphorylase a and C subunit as substrates, the cellular phosphatase resembled a multimeric form of PP-2A. PP-1 was ineffective against native C subunit, but it was able to dephosphorylate Thr-197 in urea-treated C subunit. Accessibility of Thr-197 phosphate to the cellular phosphatase was enhanced by storage of C subunit in a phosphate-free buffer or by inclusion of modest concentrations of urea in the reactions and was reduced by salt concentrations in the physiological range and/or by amino-terminal myristoylation. It is concluded that a multimeric form of PP-2A or a closely related enzyme from cell extracts is capable of removing the Thr-197 phosphate from native C subunit in vitro and could account for significant turnover of this phosphate in intact cells.
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Affiliation(s)
- S Liauw
- Department of Biochemistry and Molecular Biology, University of Oklahoma Health Sciences Center, Oklahoma City 73190, USA
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Petrasek PF, Liauw S, Romaschin AD, Walker PM. Salvage of postischemic skeletal muscle by monoclonal antibody blockade of neutrophil adhesion molecule CD18. J Surg Res 1994; 56:5-12. [PMID: 7903992 DOI: 10.1006/jsre.1994.1002] [Citation(s) in RCA: 26] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Reperfusion of ischemic skeletal muscle is associated with neutrophil (PMN) adherence to damaged endothelium and PMN-mediated tissue destruction. Neutrophils may attach to endothelium through surface adhesive molecules, such as CD18. The purpose of this study was to determine whether monoclonal antibody blockade of CD18 would reduce skeletal muscle necrosis associated with ischemia and reperfusion. In rabbits, an entire hindlimb was rendered ischemic for 4 hr, followed by 48 hr of in vivo reperfusion. Animals were allocated to one of five treatment groups: ischemia/reperfusion without treatment (I/R controls), I/R plus treatment with the anti-CD18 antibody IB4 (end-ischemic 2 mg/kg dose), I/R plus treatment with an identical dose of isotype-matched control Ig, I/R plus anterior compartment fasciotomy, or I/R plus both IB4 and fasciotomy. After 48 hr of reperfusion anterior tibial muscle necrosis was assessed (by tetrazolium staining and computerized planimetry), wet:dry muscle weights (W:D) were determined, and muscle PMN sequestration was measured by myeloperoxidase (MPO) activity. IB4-treated animals exhibited markedly reduced muscle MPO activity, compared to untreated animals. Although all interventions reduced edema formation (W:D ratios), none did so significantly. IB4 treatment reduced muscle necrosis when used alone (to 28 +/- 7%, vs. 48% +/- 6% in untreated controls), however this was not statistically significant (P = 0.06).2+ Fasciotomy significantly reduced necrosis (to 22 +/- 2%, P < 0.05); however, the addition of IB4 to fasciotomy resulted in necrosis that was significantly lower than that after fasciotomy alone (12 +/- 4%, P < 0.05 vs fasciotomy group) and the least necrosis of any group.(ABSTRACT TRUNCATED AT 250 WORDS)
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Affiliation(s)
- P F Petrasek
- R. Fraser Elliot Vascular Surgery Research Laboratory, University of Toronto, Ontario, Canada
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Rubin BB, Chang G, Liauw S, Young A, Romaschin A, Walker PM. Phospholipid peroxidation deacylation and remodeling in postischemic skeletal muscle. Am J Physiol 1992; 263:H1695-702. [PMID: 1336314 DOI: 10.1152/ajpheart.1992.263.6.h1695] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Reperfusion of ischemic skeletal muscle is associated with white blood cell (WBC) sequestration and hydroperoxy-conjugated diene (HCF) formation, a marker of free radical-mediated phospholipid peroxidation. The purpose of this study was to define the kinetics of phospholipid fatty acyl peroxidation, deacylation, and remodeling in postischemic skeletal muscle during prolonged reperfusion in vivo, and to determine whether reperfusion with WBC and plasma-depleted blood would attenuate postischemic phospholipid peroxidation and myocyte necrosis. The isolated, paired, canine gracilis muscle model was used. After 5 h of ischemia, muscles underwent unaltered reperfusion or initial reperfusion with WBC-deficient blood cells resuspended in hydroxyethyl starch, followed by return to normal circulation (modified reperfusion). The concentration of native fatty acids and HCDs of linoleic acid extracted from muscle phospholipids was quantified by gas chromatography and positively identified by mass spectrometry. Ischemia and reperfusion resulted in phospholipid deacylation and a selective increase in phospholipid stearic acid content, but had no effect on total phospholipid phosphorus. Modified reperfusion decreased 1) early HCD formation (54%) and 2) postischemic skeletal muscle necrosis (49%). These data suggest that reperfusion results in phospholipid deacylation and remodeling, and that the initial oxidant stress during reperfusion may be a significant determinant of ultimate muscle necrosis.
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Affiliation(s)
- B B Rubin
- Division of Vascular Surgery and Clinical Biochemistry, Toronto General Hospital, Ontario, Canada
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Rubin BB, Liauw S, Tittley J, Romaschin AD, Walker PM. Prolonged adenine nucleotide resynthesis and reperfusion injury in postischemic skeletal muscle. Am J Physiol 1992; 262:H1538-47. [PMID: 1590458 DOI: 10.1152/ajpheart.1992.262.5.h1538] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Skeletal muscle ischemia results in energy depletion and intracellular acidosis. Reperfusion is associated with impaired adenine nucleotide resynthesis, edema formation, and myocyte necrosis. The purpose of these studies was to define the time course of cellular injury and adenine nucleotide depletion and resynthesis in postischemic skeletal muscle during prolonged reperfusion in vivo. The isolated canine gracilis muscle model was used. After 5 h of ischemia, muscles were reperfused for either 1 or 48 h. Lactate and creatine phosphokinase (CPK) release during reperfusion was calculated from arteriovenous differences and blood flow. Adenine nucleotides, nucleosides, bases, and creatine phosphate were quantified by high-performance liquid chromatography, and muscle necrosis was assessed by nitroblue tetrazolium staining. Reperfusion resulted in a rapid release of lactate, which paralleled the increase in blood flow, and a delayed but prolonged release of CPK. Edema formation and muscle necrosis increased between 1 and 48 h of reperfusion (P less than 0.05). Recovery of energy stores during reperfusion was related to the extent of postischemic necrosis, which correlated with the extent of nucleotide dephosphorylation during ischemia (r = 0.88, P less than 0.001). These results suggest that both adenine nucleotide resynthesis and myocyte necrosis, which are protracted processes in reperfusing skeletal muscle, are related to the extent of nucleotide dephosphorylation during ischemia.
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Affiliation(s)
- B B Rubin
- Division of Vascular Surgery, R. Fraser Elliott Vascular Research Laboratory, Toronto General Hospital, University of Toronto, Ontario, Canada
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Rubin B, Tittley J, Chang G, Smith A, Liauw S, Romaschin A, Walker PM. A clinically applicable method for long-term salvage of postischemic skeletal muscle. J Vasc Surg 1991; 13:58-67; discussion 67-8. [PMID: 1846214 DOI: 10.1067/mva.1991.25387] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
The clinical significance and applicability of interventions aimed at reducing reperfusion injury in postischemic skeletal muscle remain unproven, since long-term muscle salvage has not been demonstrated by most treatment protocols that attenuate early reperfusion injury. We have shown that reperfusion of ischemic skeletal muscle results in an early and prolonged sequestration of white blood cells and activation of the alternative complement cascade. The purpose of this study was to determine if 40 minutes of reperfusion with blood depleted of white blood cells and complement proteins, followed by 2 days of normal perfusion, would reduce muscle necrosis after 5 hours of ischemia. The isolated paired canine gracilis muscle model was used. The treatment muscle was initially reperfused with arterial blood that had been spun, washed, passed through a leukocyte removal filter, and resuspended in hydroxyethyl starch (greater than 99.9% removal of white blood cells and the complement proteins factor B and C4). The contralateral control muscle was subjected to unaltered reperfusion. Blood flow (ml/min/100 gm) was measured by timed collection of gracilis venous blood. Myeloperoxidase activity (absorbance at 655 nm/min/mg tissue protein) in muscle biopsies was used to monitor white blood cell sequestration. After 48 hours of reperfusion in vivo, necrosis was quantified by nitroblue tetrazolium staining. Initial reperfusion with white blood cell and complement depleted blood significantly reduced muscle necrosis (53% +/- 3% vs 29% +/- 8%, p less than 0.0025, paired t test). Early blood flow was improved, (p = 0.0025, repeated measure-ANOVA), but subsequent white blood cell sequestration was not altered (p = 0.33, repeated measure-ANOVA). This suggests that a significant amount of white blood cell mediated injury occurs during the first 40 minutes of reperfusion. Preventing early complement activation and white blood cell mediated reperfusion injury is an intervention that is feasible during surgery and may result in clinically significant salvage of postischemic skeletal muscle.
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Affiliation(s)
- B Rubin
- Department of Vascular Surgery, R. Fraser Elliott Vascular Research Laboratory, Toronto General Hospital, Ontario, Canada
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Rubin BB, Smith A, Liauw S, Isenman D, Romaschin AD, Walker PM. Complement activation and white cell sequestration in postischemic skeletal muscle. Am J Physiol 1990; 259:H525-31. [PMID: 2167024 DOI: 10.1152/ajpheart.1990.259.2.h525] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
After skeletal muscle ischemia, tissue damage is augmented during reperfusion. White blood cells (WBCs) and complement proteins may participate in the reperfusion injury. The purpose of this study was to define the kinetics of classical and alternative pathway complement activation and WBC sequestration by postischemic skeletal muscle during the first 48 h of reperfusion in vivo. The isolated canine gracilis muscle model was used. Systemic levels of the complement proteins factor B (alternative pathway) and C4 (classical pathway) were quantitated by hemolytic assay. WBC sequestration was measured by gracilis arterial-venous WBC differences and tissue myeloperoxidase activity. Reperfusion was associated with an 18% decrease in systemic factor B levels but no consistent change in systemic C4 levels. WBCs were sequestered during the first 4 h of reperfusion, and tissue myeloperoxidase activity was elevated 97-fold after 48 h of reperfusion. These results suggest that skeletal muscle ischemia-reperfusion stimulates 1) activation of the alternative but not the classical complement pathway and 2) an immediate and prolonged sequestration of WBCs.
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Affiliation(s)
- B B Rubin
- Division of Vascular Surgery, Toronto General Hospital, Ontario, Canada
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Lindsay TF, Liauw S, Romaschin AD, Walker PM. The effect of ischemia/reperfusion on adenine nucleotide metabolism and xanthine oxidase production in skeletal muscle. J Vasc Surg 1990; 12:8-15. [PMID: 2374259 DOI: 10.1067/mva.1990.19946] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Prolonged ischemia to skeletal muscle as occurs after an acute arterial occlusion results in alterations in adenine nucleotide metabolism. Adenosine triphosphate continues to be used for cellular functions, and an ischemia-induced degradation of phosphorylated adenine nucleotides is initiated. In this experiment we demonstrated the time-dependent aspect of adenine nucleotide depletion during ischemia and the production of large quantities of soluble precursors. In addition, we studied the rate of conversion of xanthine dehydrogenase to xanthine oxidase, a potential source of oxygen-free radicals, after controlled periods of total normothermic ischemia (4 hours and 5 hours) and during the reperfusion phase. During ischemia complete depletion of creatine phosphate occurred in both groups, and adenosine triphosphate fell from 22.1 +/- 1.3 to 10.3 +/- 1.4 mumol/gm dry weight after 4 hours and from 21.6 +/- 0.7 to 3.9 +/- 0.8 mumol/gm dry weight after 5 hours (p less than 0.05). During reperfusion, creatine phosphokinase resynthesis occurred in both groups, but adenosine triphosphate levels were not significantly increased (p greater than 0.05). A washout of lipid soluble products of adenine nucleotide metabolism occurred equally in both groups. The relationship between phosphorylated adenine nucleotides as measured by the energy charge potential fell significantly in both groups (p less than 0.05), but after the shorter period of ischemia (4 hours it returned to normal during early reperfusion but did not after 5 hours of ischemia. There was 21% +/- 4% necrosis after 4 hours and 51% +/- 8% after 5 hours of ischemic stress when assessed at 48 hours. In conclusion, the degree of adenine nucleotide degeneration as determined primarily by the length of the ischemic period, may be the most important determinant of the ultimate extent of skeletal muscle ischemic necrosis that results from an acute interruption of circulation.
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Affiliation(s)
- T F Lindsay
- Division of Vascular Surgery, R. Fraser Elliott Vascular Research Laboratory, University of Toronto, Toronto General Hospital, Ontario
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