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Tam CCF, Siu D, Tse HF. COVID-19 and Acute Coronary Syndrome: Lessons for Everyone. Lancet Reg Health West Pac 2021; 19:100346. [PMID: 34957429 PMCID: PMC8692128 DOI: 10.1016/j.lanwpc.2021.100346] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 10/30/2022]
Affiliation(s)
- Chor-Cheung Frankie Tam
- Cardiology Division, Department of Medicine, Queen Mary Hospital, the University of Hong Kong, Hong Kong SAR, China
| | - David Siu
- Cardiology Division, Department of Medicine, Queen Mary Hospital, the University of Hong Kong, Hong Kong SAR, China
| | - Hung Fat Tse
- Cardiology Division, Department of Medicine, Queen Mary Hospital, the University of Hong Kong, Hong Kong SAR, China
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Lam CSP, Mulder H, Lopatin Y, Vazquez-Tanus JB, Siu D, Ezekowitz J, Pieske B, O'Connor CM, Roessig L, Patel MJ, Anstrom KJ, Hernandez AF, Armstrong PW. Blood Pressure and Safety Events With Vericiguat in the VICTORIA Trial. J Am Heart Assoc 2021; 10:e021094. [PMID: 34743540 PMCID: PMC8751950 DOI: 10.1161/jaha.121.021094] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Background Although safety and tolerability of vericiguat were established in the VICTORIA (Vericiguat Global Study in Subjects With Heart Failure With Reduced Ejection Fraction) trial in patients with heart failure with reduced ejection fraction, some subgroups may be more susceptible to symptomatic hypotension, such as older patients, those with lower baseline systolic blood pressure (SBP), or those concurrently taking angiotensin receptor neprilysin inhibitors. We described the SBP trajectories over time and compared the occurrence of symptomatic hypotension or syncope by treatment arm in potentially vulnerable subgroups in VICTORIA. We also evaluated the relation between the efficacy of vericiguat and baseline SBP. Methods and Results Among patients receiving at least 1 dose of the study drug (n=5034), potentially vulnerable subgroups were those >75 years old (n=1395), those with baseline SBP 100–110 mm Hg (n=1344), and those taking angiotensin receptor neprilysin inhibitors (n=730). SBP trajectory was plotted as mean change from baseline over time. The treatment effect on time to symptomatic hypotension or syncope was evaluated overall and by subgroup, and the primary efficacy composite outcome (heart failure hospitalization or cardiovascular death) across baseline SBP was examined using Cox proportional hazards models. SBP trajectories showed a small initial decline in SBP with vericiguat in those >75 years old (versus younger patients), as well as those receiving angiotensin receptor neprilysin inhibitors (versus none), with SBP returning to baseline thereafter. Patients with SBP <110 mm Hg at baseline showed a trend to increasing SBP over time, which was similar in both treatment arms. Safety event rates were generally low and similar between treatment arms within each subgroup. In Cox proportional hazards analysis, there were similar numbers of safety events with vericiguat versus placebo (adjusted hazard ratio [HR], 1.18; 95% CI, 0.99–1.39; P=0.059). No difference existed between treatment arms in landmark analysis beginning after the titration phase (ie, post 4 weeks) (adjusted HR, 1.14; 95% CI, 0.93–1.38; P=0.20). The benefit of vericiguat compared with placebo on the primary composite efficacy outcome was similar across the spectrum of baseline SBP (P for interaction=0.32). Conclusions These data demonstrate the safety of vericiguat in a broad population of patients with worsening heart failure with reduced ejection fraction, even among those predisposed to hypotension. Vericiguat’s efficacy persisted regardless of baseline SBP. Registration URL: https://www.clinicaltrials.gov; Unique identifier: NCT02861534.
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Affiliation(s)
- Carolyn S P Lam
- National Heart Centre Singapore & Duke-National University of Singapore Singapore
| | - Hillary Mulder
- Duke Clinical Research InstituteDuke University School of Medicine Durham NC
| | - Yuri Lopatin
- Volgograd State Medical UniversityRegional Cardiology Centre Volgograd Volgograd Russian Federation
| | - Jose B Vazquez-Tanus
- Ponce School of Medicine Ponce Puerto Rico.,Research & Cardiovascular Center and Cardiometabolic Research Center Ponce Puerto Rico
| | - David Siu
- Li Ka Shing Faculty of Medicine The University of Hong Kong Hong Kong
| | | | - Burkert Pieske
- Charité University MedicineGerman Heart Center Berlin Germany
| | | | | | | | - Kevin J Anstrom
- Duke Clinical Research InstituteDuke University School of Medicine Durham NC
| | - Adrian F Hernandez
- Duke Clinical Research InstituteDuke University School of Medicine Durham NC
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Chang RSK, Lui KHK, Ip W, Yeung E, Yung AWY, Leung H, Fung ELW, Fung BBH, Chan ELY, Poon TL, Wong HT, Siu D, Cheng K, Zhu CXL, Fong GCY, Chu J, Lui CHT, Yau M. Update to the Hong Kong Epilepsy Guideline: evidence-based recommendations for clinical management of women with epilepsy throughout the reproductive cycle. Hong Kong Med J 2021; 26:421-431. [PMID: 33089787 DOI: 10.12809/hkmj198367] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Affiliation(s)
- R S K Chang
- Department of Medicine, Queen Mary Hospital, Hong Kong
| | - K H K Lui
- Department of Medicine, Tseung Kwan O Hospital, Hong Kong
| | - W Ip
- Department of Medicine, Tseung Kwan O Hospital, Hong Kong
| | - E Yeung
- Department of Medicine, Pamela Youde Nethersole Eastern Hospital, Hong Kong
| | | | - H Leung
- Department of Medicine and Therapeutics, Prince of Wales Hospital, Hong Kong
| | - E L W Fung
- Department of Paediatrics, Prince of Wales Hospital, Hong Kong
| | | | - E L Y Chan
- Department of Medicine and Geriatrics, Tuen Mun Hospital, Hong Kong
| | - T L Poon
- Department of Neurosurgery, Queen Elizabeth Hospital, Hong Kong
| | - H T Wong
- Department of Neurosurgery, Kwong Wah Hospital, Hong Kong
| | - D Siu
- Department of Radiology, Kwong Wah Hospital, Hong Kong
| | - K Cheng
- Department of Neurosurgery, Queen Mary Hospital, Hong Kong
| | - C X L Zhu
- Department of Surgery, Prince of Wales Hospital, Hong Kong
| | | | - J Chu
- Department of Medicine, Queen Mary Hospital, Hong Kong
| | - C H T Lui
- Department of Medicine, Tseung Kwan O Hospital, Hong Kong
| | - M Yau
- Department of Paediatrics, Prince of Wales Hospital, Hong Kong
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Pieske B, Patel MJ, Westerhout CM, Anstrom KJ, Butler J, Ezekowitz J, Hernandez AF, Koglin J, Lam CS, Ponikowski P, Roessig L, Voors AA, O'Connor CM, Armstrong PW, Abidin IZ, Atar D, Bahit MC, Benecke JLA, Bocchi EA, Bonderman D, Cho M, Chiang C, Cohen‐Solal A, Cowie M, Edelmann F, Emdin M, Escobedo J, Ezekowitz JA, Givertz MM, Kaye DM, Lanas F, Lassus J, Lewis BS, Lopatin Y, López‐Sendón J, Lund LH, McDonald K, Melenovský V, Mosterd A, Noori E, Oto MA, Palomino ALG, Piña IL, Ponikowski P, Pouleur A, Refsgaard J, Reyes E, Saldarriaga C, Senni M, Sim D, Siu D, Sliwa‐Hähnle K, Sweitzer NK, Troughton RW, Tsutsui H, Tziakas DN, Vazquez‐Tanus JB, Zhang J. Baseline features of the VICTORIA (Vericiguat Global Study in Subjects with Heart Failure with Reduced Ejection Fraction) trial. Eur J Heart Fail 2019; 21:1596-1604. [DOI: 10.1002/ejhf.1664] [Citation(s) in RCA: 49] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/31/2019] [Accepted: 10/07/2019] [Indexed: 01/22/2023] Open
Affiliation(s)
- Burkert Pieske
- Charité University Medicine, German Heart Center Berlin Germany
| | | | | | | | - Javed Butler
- Department of MedicineUniversity of Mississippi Medical Center Jackson MS USA
| | | | | | | | - Carolyn S.P. Lam
- National Heart Centre Singapore & Duke‐National University of Singapore Singapore
| | | | | | - Adriaan A. Voors
- Groningen Heart Failure Research Institute Groningen The Netherlands
| | - Christopher M. O'Connor
- Duke Clinical Research InstituteDuke University Durham NC USA
- Inova Heart and Vascular Institute Falls Church VA USA
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Tan K, Cheung CL, Yeung CY, Siu D, Leung J, Pang HK. Genetic screening for familial hypercholesterolaemia in Hong Kong. Hong Kong Med J 2018; 24 Suppl 3:7-10. [PMID: 29937437] [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] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/08/2023] Open
Affiliation(s)
- K Tan
- Department of Medicine, The University of Hong Kong
| | - C L Cheung
- Department of Pharmacology and Pharmacy, The University of Hong Kong
| | - C Y Yeung
- Endocrine and Diabetes Centre, Hong Kong Sanatorium and Hospital
| | - D Siu
- Department of Medicine, The University of Hong Kong
| | - J Leung
- Department of Medicine, Ruttonjee Hospital
| | - H K Pang
- Department of Medicine, Pamela Youde Nethersole Eastern Hospital
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Tam CC, Chan K, Lam S, Yung A, Lam YM, Chan C, Siu D, Tse HF. One-year clinical outcomes of patients implanted with a Resolute Onyx™ zotarolimus-eluting stent. J Int Med Res 2017; 46:457-463. [PMID: 28758853 PMCID: PMC6011307 DOI: 10.1177/0300060517717826] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Objective To evaluate the 1-year clinical outcomes of patients who received the Resolute Onyx™ stent. Methods This was a single-centre, retrospective registry analysis that reviewed the clinical data from all patients who were implanted with a Resolute Onyx™ stent between March 2015 and February 2016. Clinical follow-up was performed at 1 year post-implantation. Results A total of 252 patients received a Resolute Onyx™ stent and two patients were lost to follow-up. The mean age of the cohort was 66.9 years and 113 (45.2%) had diabetes mellitus. Thirty-eight patients (15.2%) had left main disease and 73 (29.2%) had three-vessel disease. A total of 175 patients (70.0%) had small vessel disease (<2.75 mm) and 210 (84.0%) had long lesions (>20 mm). The 1-year target lesion failure was 4.4% (11 of 250), cardiovascular death occurred in eight patients (3.2%), ischaemia-driven target lesion revascularization was undertaken in five patients (2.0%) and stent thrombosis occurred in one patient (0.4%). Conclusion The Resolute Onyx™ stent showed a favourable 1-year clinical performance in a real-world population.
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Affiliation(s)
- Chor Cheung Tam
- Division of Cardiology, Queen Mary Hospital, University of Hong Kong, Hong Kong
| | - Kelvin Chan
- Division of Cardiology, Queen Mary Hospital, University of Hong Kong, Hong Kong
| | - Simon Lam
- Division of Cardiology, Queen Mary Hospital, University of Hong Kong, Hong Kong
| | - Arthur Yung
- Division of Cardiology, Queen Mary Hospital, University of Hong Kong, Hong Kong
| | - Yui Ming Lam
- Division of Cardiology, Queen Mary Hospital, University of Hong Kong, Hong Kong
| | - Carmen Chan
- Division of Cardiology, Queen Mary Hospital, University of Hong Kong, Hong Kong
| | - David Siu
- Division of Cardiology, Queen Mary Hospital, University of Hong Kong, Hong Kong
| | - Hung Fat Tse
- Division of Cardiology, Queen Mary Hospital, University of Hong Kong, Hong Kong
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Tam CC, Kwok J, Wong A, Yung A, Shea C, Kong SL, Tang WH, Siu D, Chan R, Lee S. Genotyping-guided approach versus the conventional approach in selection of oral P2Y12 receptor blockers in Chinese patients suffering from acute coronary syndrome. J Int Med Res 2016; 45:134-146. [PMID: 28222641 PMCID: PMC5536604 DOI: 10.1177/0300060516677190] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Objective The CYP2C19 loss-of-function (LoF) allele is present in half of the East Asian population and is associated with high on-treatment platelet reactivity (HTPR). This study aimed to investigate whether a rapid genotyping-guided approach is feasible and efficacious for selecting P2Y12 receptor blockers in Chinese patients suffering from acute coronary syndrome (ACS). Methods This was a single-centre, prospective, randomized, open-label study. A total of 132 patients with ACS were randomized to the rapid genotyping-guided treatment group (GG, N = 65) or the standard treatment group (SG, N = 67). Patients in the GG group were genotyped by the Verigene system. Patients with the CYP2C19 LoF allele were switched to ticagrelor and all remaining patients continued on clopidogrel. The endpoints were HTPR at 24 hours after the first loading dose of clopidogrel and 1 month afterwards. Results Forty patients in the GG group switched to ticagrelor, while others continued on clopidogrel. The incidence of HTPR in the GG vs SG groups was 9.2% vs 40.3% at 24 hours and 6.5% vs 32.3% at 1 month, respectively. Rapid point-of-care genotyping showed 100% concordance with conventional genotyping by real-time polymerase chain reaction. Conclusions In Chinese patients suffering from ACS, the rapid genotyping-guided approach for selecting P2Y12 receptor blockers is feasible and reduces the incidence of HTPR. Clinical Trial Registration URL: http://clinicaltrials.gov . Unique identifier: NCT01994941.
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Affiliation(s)
- Chor Cheung Tam
- 1 Division of Cardiology, Queen Mary Hospital, The University of Hong Kong
| | - Janette Kwok
- 2 Division of Transplantation and Immunogenetics, Queen Mary Hospital, The University of Hong Kong
| | - Anthony Wong
- 1 Division of Cardiology, Queen Mary Hospital, The University of Hong Kong
| | - Arthur Yung
- 1 Division of Cardiology, Queen Mary Hospital, The University of Hong Kong
| | - Catherine Shea
- 1 Division of Cardiology, Queen Mary Hospital, The University of Hong Kong
| | - Shun Ling Kong
- 1 Division of Cardiology, Queen Mary Hospital, The University of Hong Kong
| | - Wing Hong Tang
- 2 Division of Transplantation and Immunogenetics, Queen Mary Hospital, The University of Hong Kong
| | - David Siu
- 1 Division of Cardiology, Queen Mary Hospital, The University of Hong Kong
| | - Raymond Chan
- 1 Division of Cardiology, Queen Mary Hospital, The University of Hong Kong
| | - Stephen Lee
- 1 Division of Cardiology, Queen Mary Hospital, The University of Hong Kong
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Mrkobrada M, Hill M, Chan M, Sigamani A, Cowan D, Kurz A, Sessler D, Jacka M, Graham M, Dasgupta M, Dunlop V, Emery D, Gulka I, Guyatt G, Heels-Ansdell D, Murkin J, Pettit S, Sahlas D, Sharma M, Sharma M, Srinathan S, St John P, Tsai S, Gelb A, O’Donnell M, Siu D, Chiu P, Sharath V, George A, Devereaux P. Covert stroke after non-cardiac surgery: a prospective cohort study. Br J Anaesth 2016; 117:191-7. [DOI: 10.1093/bja/aew179] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/30/2016] [Indexed: 11/13/2022] Open
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Siu D, Wong CK, Chan PH, Poh YK, Poh MZ. HEAD-TO-HEAD COMPARISON OF A CAMERA-BASED SMARTPHONE APPLICATION CARDIIO RHYTHMTM WITH ALIVECOR ® HEART MONITOR FOR ATRIAL FIBRILLATION SCREENING IN PRIMARY HEALTHCARE SETTING. J Am Coll Cardiol 2016. [DOI: 10.1016/s0735-1097(16)30697-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Wong GKC, Lam SW, Wong A, Lai M, Siu D, Poon WS, Mok V. MoCA-assessed cognitive function and excellent outcome after aneurysmal subarachnoid hemorrhage at 1 year. Eur J Neurol 2014; 21:725-30. [PMID: 24471651 DOI: 10.1111/ene.12363] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2013] [Accepted: 12/17/2013] [Indexed: 11/29/2022]
Affiliation(s)
- G. K. C. Wong
- Division of Neurosurgery; Department of Surgery; Prince of Wales Hospital; Chinese University of Hong Kong; Shatin New Territories Hong Kong SAR China
| | - S. W. Lam
- Division of Neurosurgery; Department of Surgery; Prince of Wales Hospital; Chinese University of Hong Kong; Shatin New Territories Hong Kong SAR China
| | - A. Wong
- Division of Neurology; Department of Medicine and Therapeutics; Prince of Wales Hospital; Chinese University of Hong Kong; Shatin New Territories Hong Kong SAR China
- Department of Psychological Studies; Hong Kong Institute of Education; New Territories Hong Kong SAR China
| | - M. Lai
- Division of Neurosurgery; Department of Surgery; Prince of Wales Hospital; Chinese University of Hong Kong; Shatin New Territories Hong Kong SAR China
| | - D. Siu
- Department of Imaging and Interventional Radiology; Prince of Wales Hospital; Chinese University of Hong Kong; Shatin New Territories Hong Kong SAR China
| | - W. S. Poon
- Division of Neurosurgery; Department of Surgery; Prince of Wales Hospital; Chinese University of Hong Kong; Shatin New Territories Hong Kong SAR China
| | - V. Mok
- Division of Neurology; Department of Medicine and Therapeutics; Prince of Wales Hospital; Chinese University of Hong Kong; Shatin New Territories Hong Kong SAR China
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Tan T, Siu D, Seale H, Heywood A, Ridda I, Dwyer D, Lo V, Ghotane S, Katelaris A, Lindley R, Wood N, Fox J, Mitchell P, Kovoor P, MacIntyre R. The Relationship Between Seasonal Influenza Vaccine Uptake and Socioeconomic Status in Western Sydney. Substudy of the Heart-Flu Study 2008–2009. Heart Lung Circ 2011. [DOI: 10.1016/j.hlc.2011.05.615] [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: 10/18/2022]
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MacIntyre R, Tan T, Heywood A, Ridda I, Seale H, Dwyer D, Lindley R, Siu D, Lo V, Katelaris A, Wood N, Fox J, Mitchell P, Kovoor P. Influenza as Risk Factor for Ischaemic Cardiac Events and the Effects of Influenza Vaccination. Outcomes from a Three-Year Prospective Case–control Study Conducted in the Australian Winters of 2008–2010 (HEART-FLU Study). Heart Lung Circ 2011. [DOI: 10.1016/j.hlc.2011.05.609] [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: 10/18/2022]
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Abstract
Geriatric hip fracture is one of the commonest fractures in orthopaedic trauma. There is a trend of further increase in its incidence in the coming decades. Besides the development of techniques and implants to overcome the difficulties in fixation of osteoporosis bone, the general management of the hip fracture is also very challenging in terms of the preparation of the generally poorer pre-morbid state and complicate social problems associated with this group of patients. In order to cope with the increasing demand, our hospital started a geriatric hip fracture clinical pathway in 2007. The aim of this pathway is to provide better care for this group of patients through multidisciplinary approach. From year 2007 to 2009, we had managed 964 hip fracture patients. After the implementation of the pathway, the pre-operative and the total length of stay in acute hospital were shortened by over 5 days. Other clinical outcomes including surgical site infection, 30 days mortality and also incidence of pressure sore improved when compared to the data before the pathway. The rate of surgical site infection was 0.98%, and the 30 days mortality was 1.67% in 2009. The active participation of physiotherapists, occupational therapists as well as medical social workers also helped to formulate the discharge plan as early as the patient is admitted. In conclusion, a well-planned and executed clinical pathway for hip fracture can improve the clinical outcomes of the geriatric hip fractures.
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Affiliation(s)
- T W Lau
- Department of Orthopaedics and Traumatology, Queen Mary Hospital, The University of Hong Kong, Pokfulam Road, Hong Kong, Hong Kong SAR, People's Republic of China.
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Abstract
AIMS Mutation of the KRAS gene predicts the clinical response to the monoclonal antibody cetuximab in patients with advanced colorectal cancer (CRC). This study aimed to perform KRAS mutation detection on formalin-fixed paraffin-embedded (FFPE) tumour tissue by two different methods for comparison. METHODS The FFPE sample was microdissected to enrich for tumour cells. KRAS exon 2 mutations were performed on 100 Chinese patients with CRC by direct nucleotide sequencing and high-resolution melting (HRM) analysis. RESULTS KRAS exon 2 mutations were detected in a total of 62 patients with the two methods combined, comprising 11 different mutant alleles. Three common mutations p.Gly12Asp, p.Gly12Val and p.Gly13Asp accounted for approximately 70% of all cases. The concordant rate between the two methods was 95%. Four mutations not initially detected by direct sequencing were identified by HRM and confirmed by sequencing of the HRM amplicons. One mutation detected by direct sequencing was inadvertently grouped as a wild-type allele by HRM software, but this was readily rectified through manual review. CONCLUSION HRM analysis is a sensitive method of detecting KRAS mutation on FFPE tumour tissue to guide cetuximab treatment and is applicable to routine molecular diagnostic service. Utilisation of HRM to screen for mutations upfront economises the resource used in the sequencing reaction.
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Affiliation(s)
- E S K Ma
- Division of Molecular Pathology, Department of Pathology, Hong Kong Sanatorium and Hospital, Happy Valley, Hong Kong, China.
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Ng C, Wong A, Siu D, Wong K, Chan E. UP-3.143: Validation of an Algorithm Based on Parameters in Non-Contrast Computerized Tomogram for Selection of Upper Ureteral Stone for Shock Wave Lithotripsy. Urology 2009. [DOI: 10.1016/j.urology.2009.07.148] [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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Abstract
We earlier devised a set of fluctuation functions that provide relative qualitative differences of the amplitude (intensity) and the wavelength (extensity) of fluctuations in entropy and volume and the entropy-volume cross fluctuations. We discuss the mixing schemes in aqueous NaCl and urea using these fluctuation functions. Our earlier studies by using the second and third derivatives of Gibbs energy indicated that their effects on H2O are qualitatively different. An NaCl hydrates 7.5 molecules of H2O but leaves the bulk H2O away from the hydration shell unperturbed. Urea, on the other hand, connects onto the hydrogen bond network of H2O but retards the degree of fluctuation inherent in H2O. The behavior of the fluctuation functions calculated here are consistent with the above mixing schemes. Furthermore, urea was found to reduce the wavelength of fluctuation more strongly than NaCl.
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Affiliation(s)
- David Siu
- Department of Chemistry, The University of British Columbia, Vancouver, British Columbia, Canada V6T 1Z1
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Siu D. Activity-dependent hepatocyte growth factor expression and its role in organogenesis and cancer growth suppression. Med Hypotheses 2005; 63:62-70. [PMID: 15193349 DOI: 10.1016/j.mehy.2004.01.031] [Citation(s) in RCA: 6] [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] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2003] [Accepted: 01/22/2004] [Indexed: 11/29/2022]
Abstract
Studies by Murphy et al. have shown that neuronal stimulation can activate immediate early genes that code for transcription factors. Recent data suggest that Ca(2+) elevation in both neuronal cytoplasmic and nuclear compartments is responsible for the coupling of synaptic excitation to gene expression. Deisseroth et al. suggest that Ca(2+) influx through L-type voltage-sensitive Ca(2+) channels (VSCCs) activates cytoplasmic Ca(2+) targets such as calmodulin (CaM). The Ca(2+)-CaM complex then translocates to the nucleus leading to Ca(2+) and cAMP response element-binding protein (CREB) phosphorylation and gene expression. Reports have shown that L-type VSCCs are found on the vagus nerve. Other studies have suggested that activation of L-type VSCCs leads to a Ca(2+) store-dependent elevation of nuclear [Ca(2+)] that triggers gene expression by more direct activation of nuclear Ca(2+)/CaM-dependent protein kinase (CaMK). Moreover, nuclear transcription factors such as DREAM are themselves Ca(2+)-dependent, further supporting the importance of both nuclear and cytoplasmic Ca(2+) elevation in regulating gene expression. Our simulation studies suggest that intense synaptic stimulation in combination with amplification by release from intracellular Ca(2+) stores can produce elevations in nuclear Ca(2+) concentration and CaMK phosphorylation leading to CREB phosphorylation and gene expression. One of the downstream events would be the production of hepatocyte growth factor (HGF). HGF has trophic, repair, therapeutic or mitotic effect on kidney, pancreas, spleen, liver, lung, heart and spinal cord. These organs and systems' regeneration can be achieved by either upregulation of HGF release from the vagus nerve or upregulation of HGF production within the system (spinal cord). Conversely, inhibition of HGF release from the vagus nerve can inhibit cancer growth. Vagus nerve seems to be the nerve that nature intends to regulate organ growth and regeneration, it is very possible that other than HGF and injurin, other growth factors could be found in the vagus nerve. Electrical depolarization and hyperpolarization of the vagus nerve would be the most natural and effective way to induce organ regeneration and suppress cancer growth, respectively. A similar pathway seems to exist for different organs as HGF has trophic, repair, therapeutic or mitotic effect on different vagally innervated organs.
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Affiliation(s)
- David Siu
- Graduate Program in Neuroscience, Departments of Psychiatry and Physiology, Kinsmen Laboratory and Brain Research Centre, University of British Columbia, 4N1-2255 Wesbrook Mall, Vancouver, BC, Canada V6T 1Z3.
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Abstract
An average, three-dimensional anatomic shape and geometry of the distal femur were generated from x-ray computed tomography data of five fresh asymptomatic cadaver knees using AutoCAD (AutoDesk, Sausalito, CA), a computer-aided design and drafting software. Each femur model was graphically repositioned to a standardized orientation using a series of alignment templates and scaled to a nominal size of 85 mm in mediolateral and 73 mm in anteroposterior dimensions. An average generic shape of the distal femur was synthesized by combining these pseudosolid models and reslicing the composite structure at different elevations using clipping and smoothing techniques in interactive computer graphics. The resulting distal femoral geometry was imported into a computer-aided manufacturing system, and anatomic prototypes of the distal femur were produced. Quantitative geometric analyses of the generic femur in the coronal and transverse planes revealed definite condylar camber (3 degrees-6 degrees) and toe-in (8 degrees-10 degrees) with an oblique patellofemoral groove (15 degrees) with respect to the mechanical axis of the femur. In the sagittal plane, each condyle could be approximated by three concatenated circular arcs (anterior, distal, and posterior) with slope continuity and a single arc for the patellofemoral groove. The results of this study may have important implications in future femoral prosthesis design and clinical applications.
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Affiliation(s)
- D Siu
- Clinical Mechanics Group, Apps Medical Research Centre, Kingston General Hospital, Ontario, Canada
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Lai KN, Lai FM, King WW, Li PK, Siu D, Leung CB, Lui SF. Dermatofibrosarcoma protuberans in a renal transplant patient. Aust N Z J Surg 1995; 65:900-2. [PMID: 8611119] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Dermatofibrosarcoma protuberans in an unusual soft tissue tumour with a propensity for local recurrence and rarely metastatic spread. Given its indolent course it may be mistaken for atypical scarring or a keloid growth. Early diagnosis and prompt wide local resection of this entity are required in order to prevent a local recurrence. We report a patient who developed locally invasive dermatofibrosarcoma protuberans 4 years after a successful renal transplantation. Although other forms of sarcoma have been reported as a complication of organ transplantation and immunosuppression, this pathology has, so far, not been reported in a transplant recipient.
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Affiliation(s)
- K N Lai
- Department of Medicine, Prince of Wales Hospital, Chinese University of Hong Kong, Hong Kong
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Abstract
Bone ingrowth in porous surfaces of human joint implants is a desired condition for long-term fixation in patients who are physically active (such as in sport or work). It is generally recognized that little actual bone ingrowth occurs. The best clinical results report between 10 and 20% of the total prosthetic surface in contact with bone will feature good bone ingrowth. One inhibiting factor is the relative motion of the bone with respect to the implant during load-bearing. This study investigated mathematically the interface micromotion (transverse reversible relative motion) between a flat metal tibial prosthetic surface of a prototype implant, and the bone at the resection site. The aim was to assess the effect of perimeter fixation versus midcondylar pin fixation and the effect of plate thickness and plate stiffness. Results showed that in the prototype design the largest reversible relative bone motion occurred at the tibial eminence. By design, the skirt fixation at the perimeter would prevent bone motion. A PCA (Howmedica Inc.) prosthesis has been widely used clinically and was chosen for a control because its fixation by two pegs beneath the condyles is a common variation on the general design of a relatively thick and stiff metal tibial support tray with pegs in each condylar area. The PCA tibial prosthesis showed the largest bone motion at the perimeter along the midcondylar mediolateral line, while being zero at the pegs. Maximum relative bone motion for the prototype was 37 μm and for the control was 101 μm. Averaged values showed the prototype to have 38% of the relative reversible bone motion of the control (PCA).
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Affiliation(s)
- M Keja
- Department of Mechanical Engineering, University of Twente, Enschede, The Netherlands
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Cooke TD, Scudamore RA, Bryant JT, Sorbie C, Siu D, Fisher B. A quantitative approach to radiography of the lower limb. Principles and applications. J Bone Joint Surg Br 1991; 73:715-20. [PMID: 1894656 DOI: 10.1302/0301-620x.73b5.1894656] [Citation(s) in RCA: 103] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
A method is described which provides standardised reproducible radiographic images of the lower limb. Anteroposterior and lateral radiographs are digitised and processed by computer to provide graphic/numeric displays of angles and linear measurements, relating the centre points of the hip, knee, and ankle. Two cases illustrate how surgical planning is facilitated when standardised data are available. These data confirm the close relationship between postoperative limb alignment and positioning of prosthetic elements.
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Affiliation(s)
- T D Cooke
- Division of Orthopaedic Surgery, Queen's University, Kingston, Ontario, Canada
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Siu D, Cooke TD, Broekhoven LD, Lam M, Fisher B, Saunders G, Challis TW. A standardized technique for lower limb radiography. Practice, applications, and error analysis. Invest Radiol 1991; 26:71-7. [PMID: 2022456 DOI: 10.1097/00004424-199101000-00013] [Citation(s) in RCA: 90] [Impact Index Per Article: 2.7] [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 normal standing radiograph, which provides a view of the knee only, is prone to errors of parallax and poor control of patient positioning. A standardized radiographic procedure was developed to control these sources of error. Anteroposterior and lateral views of the lower limb (hip and knee) are obtained without moving the patient from a standardized position; this includes control of ankle position and limb rotation. To correct for parallax error, radiopaque markers are positioned between the patient and the x-ray source. The locations of bone landmarks and reference markers on the radiographs are digitized, and a software package provides a display of key parameters. Error analysis of the method confirmed that most angles were sensitive to contrived positional variations, especially limb rotation and knee flexion. Load distribution between limbs was not critical. The greatest error was random. Most angles were reproducible within +/- 1.3 degrees or less at 95% confidence.
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Affiliation(s)
- D Siu
- Apps Medical Research Centre, Kingston General Hospital, Ontario, Canada
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Cooke TD, Pichora D, Siu D, Scudamore RA, Bryant JT. Surgical implications of varus deformity of the knee with obliquity of joint surfaces. J Bone Joint Surg Br 1989; 71:560-5. [PMID: 2768297 DOI: 10.1302/0301-620x.71b4.2768297] [Citation(s) in RCA: 79] [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] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Some arthritic knees with varus deformity show excessive valgus angulation of the femoral joint surface with proximal tibia vara. This causes a downward and medial inclination of the articular surfaces in the coronal plane. The patients we studied had a medial shift of the standing load-bearing axis, and arthritic changes mainly in the medial compartment. Some also had lateral tibial subluxation with twisting of the distal femur and proximal tibia in opposite directions. We assessed the articular geometry by precise radiographic analysis, and compared the results with those in normal volunteers and a group of osteoarthritic patients. The prevalence of this type of deformity in our osteoarthritic patients was 11.5%; its recognition allows the use of specific operative correction that may include double osteotomy or the precise orientation of prosthetic components.
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Affiliation(s)
- T D Cooke
- Queen's University, Kingston, Ontario
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Wyss UP, Cooke TD, Yoshioka Y, Bryant JT, Siu D, Murphy L. Alignment of the first metatarsal-phalangeal joint: important criteria for a new joint replacement. J Biomed Eng 1989; 11:19-24. [PMID: 2927095 DOI: 10.1016/0141-5425(89)90160-x] [Citation(s) in RCA: 5] [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: 01/03/2023]
Abstract
Joint replacement is one of many options for the treatment of the first metatarsophalangeal (MTP) joint. Studies of the geometry of that joint have shown that it consists of two distinct articulations, the metatarsophalangeal and the MT-sesamoidal. Both are important, but the MT-sesamoidal tolerates only small deviations from an ideal alignment. The aim of this study was to investigate the alignment of the first MTP joint of a potential patient population, in order to design an optimal surface replacement. One measurement, the extension angle between the MT and the proximal phalanx was found to be the most important alignment criterion for the successful design of an implant and the necessary instruments. This angle controls the delicate interplay between the metatarsal head and the sesamoids and tolerates only small deviations from the normal range before the chance of sesamoidal subluxation increases significantly. The pre-operative knowledge of this and other alignment criteria is important for the ideal placement of an anatomical implant.
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Affiliation(s)
- U P Wyss
- Clinical Mechanics Group, Queen's University, Kingston, Ontario, Canada
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Wevers H, Siu D, Cooke T. Questor® precision radiography for lower limb alignment. BIOMED ENG-BIOMED TE 1988. [DOI: 10.1515/bmte.1988.33.s2.281] [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: 11/15/2022]
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Yoshioka Y, Siu D, Cooke TD. The anatomy and functional axes of the femur. J Bone Joint Surg Am 1987; 69:873-80. [PMID: 3597501] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Linear and angular measurements were made on thirty-two cadaveric femora with respect to the mechanical (functional) axes of the bone. The long axis was defined as a line from the center of the femoral head to the anterolateral attachment of the posterior cruciate ligament. The transverse axis was defined as a line through the posterior cruciate ligament parallel to the line connecting each epicondyle. The condylar width, the length of each interepicondylar line, correlated well with depth, but the projections of the condyles from the transverse plane revealed significant variations from specimen to specimen. Considerable variation also was found between femora in terms of angular dimensions (that is, the angle of anteversion and the neck-shaft angle proximally, and the valgus angle of the femoral shaft distally). Considerable interspecimen variation in the angles between the transcondylar plane and the femoral center, in accord with the valgus angle of the femoral shaft distally, was also noted. The mean transcondylar valgus angle (described as the tangent of the condyles to the perpendicular of the long axis) was 3.8 degrees. In contrast, little variation among specimens was noted for the angle made by the shaft and the long axis.
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Sorbie C, Shiba R, Siu D, Saunders G, Wevers H. The development of a surface arthroplasty for the elbow. Clin Orthop Relat Res 1986:100-3. [PMID: 3720111] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Complex kinematics, anatomical features, and load distribution have contributed to the poor function of constrained and semiconstrained cemented arthroplasties of the elbow. Resurfacing by porous-coated components has the potential, by reproduction of normal joint geometry and restoration of ligament balance, to re-create relatively normal kinematics and load-bearing and provide relief of pain. A method was developed to provide information on the geometry of the lower humeral joint surface and olecranon fossa. The information gained was used to design components to resurface the trochlea, capitellum, and olecranon fossa. A technique was also developed to remove a minimal amount of subchondral bone from the ulna and humerus in a precisely directed fashion for exact fit of the porous-coated components.
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Abstract
Five patients with heavy proteinuria and nonparasitic chyluria due to congenital abnormalities of the lymphatic system are described. Renal biopsies confirmed the clinical suspicion of an underlying glomerulonephritis. The coexistence of glomerulonephritis and chyluria in these patients was thought coincidental. Tests of value in detecting a concomitant glomerulonephritis in these patients with chyluria include urinary RBC morphology, quantitation of 24-hour urinary protein, and immunoelectrophoresis of serum and urinary proteins. Contrary to previous reports, the present study suggests that chyluria does not produce proteinuria of enough severity to cause hypoproteinemia.
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Abstract
A three-dimensional finite element model of the proximal tibia has been developed to provide a base line for further modeling of prosthetic resurfaced tibiae. The geometry for the model was developed by digitizing coronal and transverse sections made with the milling machine, from one fresh tibia of average size. The load is equally distributed between the medial and lateral compartments over contact areas that were reported in the literature. An indentation test has been used to measure the stiffness and the ultimate strength of cancellous bone in four cadaver tibiae. These values provided the statistical basis for characterising the inhomogeneous distribution of the cancellous bone properties in the proximal tibia. All materials in the model were assumed to be linearly elastic and isotropic. Mechanical properties for the cortical bone and cartilage have been taken from the literature. Results have been compared with strain gage tests and with a two-dimensional axisymmetric finite element model both from the literature. Qualitative comparison between trabecular alignment, and the direction of the principal compressive stresses in the cancellous bone, showed a good relationship. Maximum stresses in the cancellous bone and cortical bone, under a load which occurs near stance phase during normal gait, show safety factors of approximately eight and twelve, respectively. The load sharing between the cancellous bone and the cortical bone has been plotted for the first 40 mm distally from the tibial eminence.
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Cooke TD, Saunders G, Siu D, Yoshioka Y, Wevers H. Universal bone cutting device for precision knee replacement arthroplasty and osteotomy. J Biomed Eng 1985; 7:45-50. [PMID: 3982009 DOI: 10.1016/0141-5425(85)90008-1] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Since malplacement contributes most to loosening of total knee replacements (TKR), a jig was devised, aligned to and mounted on the tibia, with a 3 degrees of freedom sliding saw. A central distractor, attached to the jig, positions and aligns the knee at 0 degrees or 90 degrees. The femur is then rigidly linked to the jig for bone cutting. Resurfacing designs (Cloutier and Townley) have been regularly implanted, aligned +/- 1 degree. This precision should minimize loosening and improve function.
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