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Soh KW, Walker C, O'Sullivan M, Wallace J. An Evaluation of the Hybrid Model for Predicting Surgery Duration. J Med Syst 2020; 44:42. [PMID: 31897758 DOI: 10.1007/s10916-019-1501-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2019] [Accepted: 11/14/2019] [Indexed: 10/25/2022]
Abstract
The degree of accuracy in surgery duration estimation directly impacts on the quality of planned surgical lists. Model selection for the prediction of surgery duration requires technical expertise and significant time and effort. The result is often a collection of viable models, the performance of which varies across different strata of the surgical population. This paper proposes a prediction framework to be used after a comprehensive model selection process has been completed for surgery duration prediction. The framework produces a partition of the surgical cases and a "hybrid model" that allocates different predictors from the collection of viable models to different parts of the surgical population. The intention is a flexible prediction process that can reassign models and adapt as surgical processes change. The framework is tested via a simulation study, and its utility is demonstrated by predicting surgery durations for Ear, Nose and Throat surgeries in a New Zealand hospital. The results indicate that the hybrid model is effective, performing better than standard model selection in two of the three simulation studies, and marginally worse when the selected model was the true underlying process.
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Pearson RA, Brooks R, Driver S, Frew JA, Pedley ID, Pilling K, Richmond N, Walker C, West S, Wilkinson M, Wyatt J, McCallum H. Magnetic Resonance-only Workflow: Implementation in a UK Centre. Clin Oncol (R Coll Radiol) 2019; 32:278. [PMID: 31786082 DOI: 10.1016/j.clon.2019.10.009] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2019] [Accepted: 10/24/2019] [Indexed: 01/06/2023]
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Kicman AT, Oftebro H, Walker C, Norman N, Cowan DA. Potential use of ketoconazole in a dynamic endocrine test to differentiate between biological outliers and testosterone use by athletes. Clin Chem 2019. [DOI: 10.1093/clinchem/39.9.1798] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
Abstract
Determination of the ratio of testosterone to epitestosterone (T/E) in urine is used to detect testosterone administration in athletes, with a ratio > 6 considered as evidence of an offense. We show that administration of ketoconazole, which inhibits testosterone biosynthesis, may be useful for differentiating between an athlete who is using testosterone and one who naturally gives a ratio > 6. In a control subject pretreated with testosterone, ketoconazole caused the ratio to increase; conversely, it caused a decrease in the ratio in an athlete under investigation. Repeated administration of ketoconazole to two normal men caused a decrease in the ratio due to a large decrease in the urinary excretion rate of testosterone relative to epitestosterone. Stimulation with human chorionic gonadotropin exacerbated the differences in excretion rates. A single administration of ketoconazole to six normal men caused the T/E ratios to decrease significantly within 8 h, a suitable time scale for use in a dynamic test.
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Yeung S, Fernandez JW, Handsfield GG, Walker C, Besier TF, Zhang J. Rapid muscle volume prediction using anthropometric measurements and population-derived statistical models. Biomech Model Mechanobiol 2019; 19:1239-1249. [PMID: 31667655 DOI: 10.1007/s10237-019-01243-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2019] [Accepted: 10/21/2019] [Indexed: 12/01/2022]
Abstract
Knowledge of subject-specific muscle volumes may be used as surrogates for evaluating muscle strength and power generated by 'fat-free' muscle mass. This study presents population-based statistical learning approaches for predicting 'fat-free' muscle volume from known anthropometric measurements. Using computed tomography (CT) imaging data to obtain lower-limb muscle volumes from 50 men and women, this study evaluated six statistical learning methods for predicting muscle volumes from anthropometric measurements: (i) stepwise regression, (ii) linear support vector machine (SVM), (iii) 2nd-order polynomial SVM, (iv) linear partial least squares regression (PLSR), (v) quadratic PLSR, and (vi) 3rd-order spline fit PLSR. These techniques have successfully been demonstrated in bioengineering applications and freely available in open-source toolkits. Analysis revealed that separating a general population into sexes and/or cohorts based on adipose level may improve prediction accuracies. The most important measures that statistically influence muscle volume predictions were shank girth, followed by sex and finally leg length, as identified using stepwise regression. SVM learning predicted muscle volume with an accuracy of 85 ± 4% when using linear interpolation, but performed poorly with an accuracy of 59 ± 6% using polynomial interpolation. The simpler linear PLSR exhibited muscle volume prediction accuracy of 87 ± 2%, while quadratic PLSR was slightly reduced at 82 ± 3%. For the spline fit PLSR, high accuracy was observed on the training data set (~ 99%) but over-fitting (a drawback of high-interpolation methods) resulted in erroneous predictions on testing data, and hence, the model was deemed unsuitable. In conclusion, use of linear PLSR models with variables of sex, leg length, and shank girth is a useful tool for predicting 'fat-free' muscle volume.
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Boynton C, Dempsey M, Walker C. Perioperative management of the heterotopic heart transplant recipient for catheter abalation of native heart ventricular tachycardia. J Cardiothorac Vasc Anesth 2019. [DOI: 10.1053/j.jvca.2019.07.103] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Laxton V, Allott R, Veluchamy S, Boynton C, Walker C. Peri-operative temperature measurement. Guideline or fantasy? J Cardiothorac Vasc Anesth 2019. [DOI: 10.1053/j.jvca.2019.07.014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Lenartova K, Gkikas A, Moravcova S, Marczin N, Simon A, Walker C. Initial United Kingdom experience with the syncardia total artificial heart. J Cardiothorac Vasc Anesth 2019. [DOI: 10.1053/j.jvca.2019.07.117] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Lucke T, Walker C, Beecham S. Experimental designs of field-based constructed floating wetland studies: A review. THE SCIENCE OF THE TOTAL ENVIRONMENT 2019; 660:199-208. [PMID: 30640088 DOI: 10.1016/j.scitotenv.2019.01.018] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/05/2018] [Revised: 01/02/2019] [Accepted: 01/03/2019] [Indexed: 06/09/2023]
Abstract
A Constructed Floating Wetland (CFW) is a relatively recent innovation in stormwater treatment and is a hydroponic device that is designed to move up and down with changing water levels as urban runoff enters a stormwater retention pond. This floating capability is designed to improve the pollutant removal efficiency of the CFW. The CFW studies undertaken so far have produced encouraging results under a range of conditions such as system size, inflow pollutant concentrations, climatic conditions, and coverage ratio. However, these results have not yet been drawn together to better understand how the various design features of a CFW influence its performance. This paper reviews the available field investigations with the aim of helping guide and improve the experimental designs and installations of future CFW installations. This in turn will improve the knowledge and acceptance of these recently developed stormwater treatment systems. One of the findings of this review was that using a percentage coverage design approach may not be as effective as improving the design efficiency. Understanding the hydraulics of the entire pond and CFW system is also critical to effective design. The review also found that the performance evaluation of future CFW installations would be improved if consideration is given to including both baseline monitoring and experimental controls.
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Irvine A, Jones A, Beattie P, Baron S, Browne F, Ashoor F, O'Neill L, Rosala-Hallas A, Sach T, Spowart C, Taams L, Walker C, Wan M, Webb N, Williamson P, Flohr C. The TREatment of severe Atopic eczema Trial (TREAT). Br J Dermatol 2018. [DOI: 10.1111/bjd.17052] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Walker C, Ehinger N, Mason B, Nayeri U, Curry C, Adams Waldorf K. A disproportionately small fetal head circumference with respect to femur length correlates with abnormal postnatal intracranial imaging and eye deficits following zika virus infection in pregnancy. Am J Obstet Gynecol 2018. [DOI: 10.1016/j.ajog.2018.10.068] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Kachikis A, Eckert L, Bardají A, Walker C, Varricchio F, Munoz F, Rouse C, Kochhar S, Bonhoeffer J, Chescheir N. Chorioamnionitis: development of a maternal outcome definition for international immunization research through the GAIA project. Am J Obstet Gynecol 2018. [DOI: 10.1016/j.ajog.2018.10.064] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Sit D, Thomas R, Giuliani M, Lee P, Shaverdian N, Walker C, Swaminath A. Can the Neutrophil to Lymphocyte Ratio (NLR) and Platelet to Lymphocyte Ratio (PLR) Predict Survival or Local Control in Patients Treated with Stereotactic Body Radiation Therapy (SBRT) for Non-Small Cell Lung Cancer (NSCLC)? A Systematic Review. Int J Radiat Oncol Biol Phys 2018. [DOI: 10.1016/j.ijrobp.2018.07.1899] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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Voruganti I, Donovan E, Walker C, Swaminath A. Systematic Review of the Incidence of Chest Wall Toxicity Following Stereotactic Body Radiation Therapy for Early Stage Non-Small Cell Lung Cancer. Int J Radiat Oncol Biol Phys 2018. [DOI: 10.1016/j.ijrobp.2018.07.1909] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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Irvine AD, Jones AP, Beattie P, Baron S, Browne F, Ashoor F, O'Neill L, Rosala-Hallas A, Sach T, Spowart C, Taams L, Walker C, Wan M, Webb N, Williamson P, Flohr C. A randomized controlled trial protocol assessing the effectiveness, safety and cost-effectiveness of methotrexate vs. ciclosporin in the treatment of severe atopic eczema in children: the TREatment of severe Atopic eczema Trial (TREAT). Br J Dermatol 2018; 179:1297-1306. [PMID: 29727479 DOI: 10.1111/bjd.16717] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/23/2018] [Indexed: 11/27/2022]
Abstract
BACKGROUND Oral systemic immunomodulatory medication is regularly used off-licence in children with severe atopic eczema. However, there is no firm evidence regarding the effectiveness, safety, cost-effectiveness and impact on quality of life from an adequately powered randomized controlled trial (RCT) using systemic medication in children. OBJECTIVES To assess whether there is a difference in the speed of onset, effectiveness, side-effect profile and reduction in flares post-treatment between ciclosporin (CyA) and methotrexate (MTX), and also the cost-effectiveness of the drugs. Treatment impact on quality of life will also be examined in addition to whether FLG genotype influences treatment response. In addition, the trial studies the immune-metabolic effects of CyA and MTX. METHODS Multicentre, parallel group, assessor-blind, pragmatic RCT of 36 weeks' duration with a 24-week follow-up period. In total, 102 children aged 2-16 years with moderate-to-severe atopic eczema, unresponsive to topical treatment will be randomized (1 : 1) to receive MTX (0·4 mg kg-1 per week) or CyA (4 mg kg-1 per day). RESULTS The trial has two primary outcomes: change from baseline to 12 weeks in Objective Severity Scoring of Atopic Dermatitis (o-SCORAD) and time to first significant flare following treatment cessation. CONCLUSIONS This trial addresses important therapeutic questions, highlighted in systematic reviews and treatment guidelines for atopic eczema. The trial design is pragmatic to reflect current clinical practice.
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Bloss HE, Walker C. Some Endogonaceous Mycorrhizal Fungi of the Santa Catalina Mountains in Arizona. Mycologia 2018. [DOI: 10.1080/00275514.1987.12025439] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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Hannon V, Burnett K, Walker C. Life in a bubble. J Cardiothorac Vasc Anesth 2018. [DOI: 10.1053/j.jvca.2018.08.045] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Singh KK, McGovern I, Walker C, Dalby M. Conscious sedation versus general anaesthesia for patients undergoing TAVI. J Cardiothorac Vasc Anesth 2018. [DOI: 10.1053/j.jvca.2018.08.035] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Verzelloni A, Walker C. An audit of postoperative use of thoracic epidural analgesia (TEA) after lung transplantation (LT). J Cardiothorac Vasc Anesth 2018. [DOI: 10.1053/j.jvca.2018.08.179] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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44
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Dutton J, Lenartova K, García Sáez D, Simon A, Walker C. Primary graft dysfunction following orthotopic cardiac transplant: a single centre experience. J Cardiothorac Vasc Anesth 2018. [DOI: 10.1053/j.jvca.2018.08.065] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Arnone D, Wise T, Walker C, Cowen PJ, Howes O, Selvaraj S. The effects of serotonin modulation on medial prefrontal connectivity strength and stability: A pharmacological fMRI study with citalopram. Prog Neuropsychopharmacol Biol Psychiatry 2018; 84:152-159. [PMID: 29409920 PMCID: PMC5886357 DOI: 10.1016/j.pnpbp.2018.01.021] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/09/2017] [Revised: 01/12/2018] [Accepted: 01/30/2018] [Indexed: 01/26/2023]
Abstract
BACKGROUND Static and dynamic functional connectivity are being increasingly used to measure the effects of disease and a range of different interventions on brain networks. While preliminary evidence suggests that static connectivity can be modulated by chronic antidepressants administration in healthy individuals and in major depression, much less is known about the acute effects of antidepressants especially on dynamic functional connectivity changes. Here we examine acute effects of antidepressants on dynamic functional connectivity within the default mode network. The default mode network is a well described network with many functions in which the role of serotonin is not clear. METHODS In this work we measured acute pharmacological effects of an infusion of the selective serotonin reuptake inhibitor (SSRI) citalopram (10 mg) in a sample of thirteen healthy volunteers randomised to receive on two occasions the active compound or placebo in a cross over dosing. RESULTS Acute citalopram administration relative to placebo increased static connectivity between the medial prefrontal cortex and right dorsolateral prefrontal cortex and posterior cingulate cortex. The SSRI also induced a reduction in variability of connectivity with the medial prefrontal cortex in the precuneus and posterior cingulate cortex. DISCUSSION The measured changes are compatible with modified serotonin cortical availability.
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Walker C, Williams S, McLean M, Lambert C, Pao C, Nwokoro C. WS19.3 Early screening and treatment of paediatric CF-Related Diabetes (CFRD) slows respiratory decline. J Cyst Fibros 2018. [DOI: 10.1016/s1569-1993(18)30228-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/14/2022]
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Yeomans ND, Graham DY, Husni ME, Solomon DH, Stevens T, Vargo J, Wang Q, Wisniewski LM, Wolski KE, Borer JS, Libby P, Lincoff AM, Lüscher TF, Bao W, Walker C, Nissen SE. Randomised clinical trial: gastrointestinal events in arthritis patients treated with celecoxib, ibuprofen or naproxen in the PRECISION trial. Aliment Pharmacol Ther 2018; 47:1453-1463. [PMID: 29667211 DOI: 10.1111/apt.14610] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/30/2017] [Revised: 12/09/2017] [Accepted: 02/21/2018] [Indexed: 12/18/2022]
Abstract
AIM To evaluate GI safety of celecoxib compared with 2 nonselective (ns) NSAIDs, as a secondary objective of a large trial examining multiorgan safety. METHODS This randomised, double-blind controlled trial analysed 24 081 patients. Osteoarthritis or rheumatoid arthritis patients, needing ongoing NSAID treatment, were randomised to receive celecoxib 100-200 mg b.d., ibuprofen 600-800 mg t.d.s. or naproxen 375-500 mg b.d. plus esomeprazole, and low-dose aspirin or corticosteroids if already prescribed. Clinically significant GI events (CSGIE-bleeding, obstruction, perforation events from stomach downwards or symptomatic ulcers) and iron deficiency anaemia (IDA) were adjudicated blindly. RESULTS Mean treatment and follow-up durations were 20.3 and 34.1 months. While on treatment or 30 days after, CSGIE occurred in 0.34%, 0.74% and 0.66% taking celecoxib, ibuprofen and naproxen. Hazard ratios (HR) were 0.43 (95% CI 0.27-0.68, P = 0.0003) celecoxib vs ibuprofen and 0.51 (0.32-0.81, P = 0.004) vs naproxen. There was also less IDA on celecoxib: HR 0.43 (0.27-0.68, P = 0.0003) vs ibuprofen; 0.40 (0.25-0.62, P < 0.0001) vs naproxen. Even taken with low-dose aspirin, fewer CSGIE occurred on celecoxib than ibuprofen (HR 0.52 [0.29-0.94], P = 0.03), and less IDA vs naproxen (0.42 [0.23-0.77, P = 0.005]). Corticosteroid use increased total GI events and CSGIE. H. pylori serological status had no influence. CONCLUSIONS Arthritis patients taking NSAIDs plus esomeprazole have infrequent clinically significant gastrointestinal events. Co-prescribed with esomeprazole, celecoxib has better overall GI safety than ibuprofen or naproxen at these doses, despite treatment with low-dose aspirin or corticosteroids.
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West N, Parkes M, Prentis J, Snowden C, McKenna J, Iqbal M, Walker C. PO-0945: Controlling motion in radiotherapy: rapid shallow ventilation for thoracic and abdominal targets. Radiother Oncol 2018. [DOI: 10.1016/s0167-8140(18)31255-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Wootten B, Yoder J, Walker C, Davis C, Sulava E, Zarow G, Loomis A. 355 A Trial of Terlipressin Compared to Small Volume Resuscitation in a Swine (Sus scrofa) Model of Uncontrolled Hemorrhage and Severe Hemorrhagic Shock. Ann Emerg Med 2017. [DOI: 10.1016/j.annemergmed.2017.07.325] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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50
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Jonasch E, Fuller G, McCutcheon I, Ding Z, Zhou L, Liu X, Kong W, Powell R, Park IY, Tannir N, Rathmell W, Dong B, Matin S, Tong X, Huang Y, Tong P, Wang J, Walker C, Sun M. The role of hepatocyte nuclear factor 1 homeobox B (HNF1B) loss in chromophobe RCC (ChRCC) development. Ann Oncol 2017. [DOI: 10.1093/annonc/mdx391.022] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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