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Carralot JP, Ruiz MA, Tam R, Armentani E, Pattabiraman VR, Kreft B. Abstract 4223: Cis-activation of PD-1+ effector T cells with dual-targeting immunocytokines generated using a novel chemical conjugation platform. Cancer Res 2022. [DOI: 10.1158/1538-7445.am2022-4223] [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: 11/16/2022]
Abstract
Abstract
Immunocytokines (IC) provide the opportunity for targeted delivery of cytokines as payloads to tissues and cells to improve safety and efficacy of cytokine-based therapies. ICs have gained significant interest in recent years and several antibody-cytokine fusion proteins have entered clinical trials. Compared to recombinant fusion proteins, we have developed an entirely different approach to IC generation based on the site-specific, chemical conjugation of synthetic cytokines to antibodies. Bright Peak generates enhanced and conjugatable cytokines using a novel protein engineering platform based on solid-phase peptide synthesis and subsequent chemical ligation of protein segments. Our synthetic cytokines can then be readily chemically conjugated to specific lysine residues in the Fc region of an existing IgG1, IgG2 or IgG4 antibody without the need for prior antibody engineering. Chemical conjugation of cytokine payloads is rapid, enabling the flexible generation of ICs based on different antibodies and payloads within weeks. We applied our technology to more than 10 antibodies and found that neither antigen binding nor payload potency and selectivity are affected by chemical conjugation. Importantly, binding of the Fc domain of ICs to Fc gamma receptors or FcRn is not significantly affected. We are initially focusing on the development of PD-1-targeted ICs to achieve dual-targeting of PD-1+ effector T cells (cis-signaling). Using several anti-PD-1 antibodies and various synthetic IL-2 variants as payloads, we created ICs with different drug-antibody ratios and explored alternative conjugation sites within the Fc region. Resulting PD-1/IL-2 ICs are highly active showing significantly enhanced potency due to avidity resulting from binding of the cytokine to PD-1+ effector T cells in cis. Our PD-1/IL-2 ICs induce strong pharmacodynamic effects in vivo, and we are currently optimizing the pharmacological profiles of PD-1-targeted ICs for clinical application. In addition, we are actively exploring cis-signaling ICs targeting different surface receptors and immune cells.
Citation Format: Jean-Philippe Carralot, Matilde Arévalo Ruiz, Robert Tam, Eric Armentani, Vijaya R. Pattabiraman, Bertolt Kreft. Cis-activation of PD-1+ effector T cells with dual-targeting immunocytokines generated using a novel chemical conjugation platform [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 4223.
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Affiliation(s)
| | | | - Robert Tam
- 1Bright Peak Therapeutics, Inc., Basel, Switzerland
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Johnson P, Chan JK, Vavasour IM, Abel S, Lee LE, Yong H, Laule C, Li DKB, Tam R, Traboulsee A, Carruthers RL, Kolind SH. Quantitative MRI findings indicate diffuse white matter damage in Susac Syndrome. Mult Scler J Exp Transl Clin 2022; 8:20552173221078834. [PMID: 35186315 PMCID: PMC8851927 DOI: 10.1177/20552173221078834] [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] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2021] [Accepted: 01/21/2022] [Indexed: 11/15/2022] Open
Abstract
Background Susac Syndrome (SuS) is an autoimmune endotheliopathy impacting the brain, retina and cochlea that can clinically mimic multiple sclerosis (MS). Objective To evaluate non-lesional white matter demyelination changes in SuS compared to MS and healthy controls (HC) using quantitative MRI. Methods 3T MRI including myelin water imaging and diffusion basis spectrum imaging were acquired for 7 SuS, 10 MS and 10 HC participants. Non-lesional white matter was analyzed in the corpus callosum (CC) and normal appearing white matter (NAWM). Groups were compared using ANCOVA with Tukey correction. Results SuS CC myelin water fraction (mean 0.092) was lower than MS(0.11, p = 0.01) and HC(0.11, p = 0.04). Another myelin marker, radial diffusivity, was increased in SuS CC(0.27μm2/ms) compared to HC(0.21μm2/ms, p = 0.008) and MS(0.23μm2/ms, p = 0.05). Fractional anisotropy was lower in SuS CC(0.82) than HC(0.86, p = 0.04). Fiber fraction (reflecting axons) did not differ from HC or MS. In NAWM, radial diffusivity and apparent diffusion coefficient were significantly increased in SuS compared to HC(p < 0.001 for both measures) and MS(p = 0.003, p < 0.001 respectively). Conclusions Our results provided evidence of myelin damage in SuS, particularly in the CC, and more extensive microstructural injury in NAWM, supporting the hypothesis that there are widespread microstructural changes in SuS syndrome including diffuse demyelination.
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Affiliation(s)
| | - JK Chan
- Department of Medicine (Neurology), University of British Columbia, Canada
| | - IM Vavasour
- Department of Radiology, University of British Columbia, Canada
- International Collaboration on Repair Discoveries (ICORD)
| | | | | | - H Yong
- Department of Medicine (Neurology), University of British Columbia, Canada
| | - C Laule
- Department of Radiology, University of British Columbia, Canada
- International Collaboration on Repair Discoveries (ICORD)
- Department of Pathology and Laboratory Medicine, University of British Columbia, Canada
- Department of Physics and Astronomy, University of British Columbia, Canada
| | - DKB Li
- Department of Medicine (Neurology), University of British Columbia, Canada
- Department of Radiology, University of British Columbia, Canada
| | - R Tam
- Department of Radiology, University of British Columbia, Canada
- School of Biomedical Engineering, University of British Columbia, Canada
| | | | - RL Carruthers
- Department of Medicine (Neurology), University of British Columbia, Canada
| | - SH Kolind
- Department of Medicine (Neurology), University of British Columbia, Canada
- Department of Radiology, University of British Columbia, Canada
- International Collaboration on Repair Discoveries (ICORD)
- Department of Physics and Astronomy, University of British Columbia, Canada
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Vavasour IM, Becquart P, Gill J, Zhao G, Yik JT, Traboulsee A, Carruthers RL, Kolind SH, Schabas AJ, Sayao AL, Devonshire V, Tam R, Moore GRW, Stukas S, Wellington CL, Quandt JA, Li DKB, Laule C. Diffusely abnormal white matter in clinically isolated syndrome is associated with parenchymal loss and elevated neurofilament levels. Mult Scler Relat Disord 2021; 57:103422. [PMID: 34871858 DOI: 10.1016/j.msard.2021.103422] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2021] [Revised: 10/23/2021] [Accepted: 11/20/2021] [Indexed: 11/19/2022]
Abstract
We characterized the frequency of diffusely abnormal white matter (DAWM) across a broad spectrum of multiple sclerosis (MS) participants. 35% of clinically isolated syndrome (CIS), 57% of relapsing remitting and 64% of secondary progressive MS participants demonstrated DAWM. CIS with DAWM had decreased cortical thickness, higher lesion load and a higher concentration of serum neurofilament light chain compared to CIS without DAWM. DAWM may be useful in identifying CIS patients with greater injury to their brains. Larger and longitudinal studies are warranted.
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Affiliation(s)
- I M Vavasour
- Radiology, University of British Columbia, Vancouver, British Columbia, Canada; International Collaboration on Repair Discoveries, University of British Columbia, Vancouver, British Columbia, Canada.
| | - P Becquart
- Pathology & Laboratory Medicine, University of British Columbia, Vancouver, British Columbia, Canada
| | - J Gill
- Pathology & Laboratory Medicine, University of British Columbia, Vancouver, British Columbia, Canada
| | - G Zhao
- MS/MRI Research Group, University of British Columbia, Vancouver, British Columbia, Canada
| | - J T Yik
- International Collaboration on Repair Discoveries, University of British Columbia, Vancouver, British Columbia, Canada; Physics & Astronomy, University of British Columbia, Vancouver, British Columbia, Canada
| | - A Traboulsee
- MS/MRI Research Group, University of British Columbia, Vancouver, British Columbia, Canada; Medicine, University of British Columbia, Vancouver, British Columbia, Canada
| | - R L Carruthers
- Medicine, University of British Columbia, Vancouver, British Columbia, Canada
| | - S H Kolind
- Radiology, University of British Columbia, Vancouver, British Columbia, Canada; International Collaboration on Repair Discoveries, University of British Columbia, Vancouver, British Columbia, Canada; MS/MRI Research Group, University of British Columbia, Vancouver, British Columbia, Canada; Medicine, University of British Columbia, Vancouver, British Columbia, Canada; Physics & Astronomy, University of British Columbia, Vancouver, British Columbia, Canada
| | - A J Schabas
- Medicine, University of British Columbia, Vancouver, British Columbia, Canada
| | - A L Sayao
- Medicine, University of British Columbia, Vancouver, British Columbia, Canada
| | - V Devonshire
- Medicine, University of British Columbia, Vancouver, British Columbia, Canada
| | - R Tam
- Radiology, University of British Columbia, Vancouver, British Columbia, Canada; MS/MRI Research Group, University of British Columbia, Vancouver, British Columbia, Canada; School of Biomedical Engineering, University of British Columbia, Vancouver, British Columbia, Canada
| | - G R W Moore
- International Collaboration on Repair Discoveries, University of British Columbia, Vancouver, British Columbia, Canada; Pathology & Laboratory Medicine, University of British Columbia, Vancouver, British Columbia, Canada; Medicine, University of British Columbia, Vancouver, British Columbia, Canada
| | - S Stukas
- Pathology & Laboratory Medicine, University of British Columbia, Vancouver, British Columbia, Canada
| | - C L Wellington
- Pathology & Laboratory Medicine, University of British Columbia, Vancouver, British Columbia, Canada
| | - J A Quandt
- Pathology & Laboratory Medicine, University of British Columbia, Vancouver, British Columbia, Canada
| | - D K B Li
- Radiology, University of British Columbia, Vancouver, British Columbia, Canada; MS/MRI Research Group, University of British Columbia, Vancouver, British Columbia, Canada; Medicine, University of British Columbia, Vancouver, British Columbia, Canada
| | - C Laule
- Radiology, University of British Columbia, Vancouver, British Columbia, Canada; International Collaboration on Repair Discoveries, University of British Columbia, Vancouver, British Columbia, Canada; Pathology & Laboratory Medicine, University of British Columbia, Vancouver, British Columbia, Canada; Physics & Astronomy, University of British Columbia, Vancouver, British Columbia, Canada
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Tang L, Ho K, Tam R, Hawkins N, Lim M, Andrade J. Machine learning for predicting AF ablation outcomes using daily heart rhythm data at baseline. Eur Heart J 2020. [DOI: 10.1093/ehjci/ehaa946.0432] [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] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Abstract
Background
While numerous studies have shown that catheter ablation is superior to antiarrhythmic drug (AAD) in treating atrial fibrillation (AF), the long term outcomes have been limited by arrhythmia recurrence. Reliable data and methods to predict ablation outcomes will thus be valuable for treatment planning.
Objective
To evaluate the utility of machine learning and various types of input variables, viz. patient characteristics at baseline, and daily heart rhythm data recorded prior to ablation for outcome prediction.
Methods
We acquired permission to analyze data collected from a randomized clinical trial that recorded daily biomeasures from >345 patients who were referred for first catheter ablation due to AF refractory to at least one AAD. After standardizing the dataset, each patient sample is characterized by a set of daily measures, viz. heart rate variability (HRV) and AF burden (AFB), which is the total minutes in AF per day. We next performed comparative analyses on 19 candidate model variants to evaluate each model's ability in identifying patients who were to experience at least one episode of AF recurrence during post-ablation period starting from day 91 up to day 365 post-ablation, per standard guidelines. We examined: i) use of a set of daily biomeasures jointly with baseline sex and age; and ii) observation lengths of the pre-ablation period. We also examined the use of baseline CHA2DS2-VASc scores, left-atrial volume (LAV), atrial diameter, medical history. We conducted multiple sets of 3-fold cross validation (CV) experiments, each fold independently trained a candidate model with 236 samples (two thirds of the dataset) and performed evaluation on the left-out samples. About 50% of cohort belongs to one class. Each fold scored a model and its input variables in terms of sensitivity (SEN), specificity (SPEC), area under receiver operating characteristic curve (AUC), etc. To circumvent risks of overfitting highly parameterized models to our training subset, we shortlisted 19 models that have few hyper-parameters, e.g. stepwise regression, random forest (RF), linear discriminant analysis (LDA).
Results
CV results demonstrated that LDA and RF gave comparable performances, with RF achieving highest AUC of 0.68±0.06 using 30 days of rhythm data prior to ablation (SEN of 65.9±7.82; SPEC of 66.3±0.57). When observation period extended to 90 days prior, AUC improved to 0.691±0.02. In contrast, use of LAV alone was not adequate to predict outcome (AUC∼0.5), and when combined with all aforementioned baseline variables, the best model achieved AUC of 0.58±0.05. Feature analyses from the trained models suggest that AFB had highest relevance in predicting outcome. Using only daily AFB, RF and LDA respectively achieved AUC of 0.608±0.04 and 0.652±0.04.
Conclusions
Our results suggest the value of pre-ablation rhythm data for improving outcome-prediction. Future work will validate these findings using large public datasets.
Funding Acknowledgement
Type of funding source: Public Institution(s). Main funding source(s): Huawei-Data Science Institute Research Program; Natural Sciences and Engineering Research Council of Canada (NSERC)
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Affiliation(s)
- L Tang
- University of British Columbia, Vancouver, Canada
| | - K Ho
- University of British Columbia, Vancouver, Canada
| | - R Tam
- University of British Columbia, Vancouver, Canada
| | - N Hawkins
- University of British Columbia, Vancouver, Canada
| | - M Lim
- University of British Columbia, Vancouver, Canada
| | - J Andrade
- University of British Columbia, Vancouver, Canada
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Kang H, Hii M, Le M, Tam R, Riddehough A, Traboulsee A, Kolind S, Freedman MS, Li DKB. Gadolinium Deposition in Deep Brain Structures: Relationship with Dose and Ionization of Linear Gadolinium-Based Contrast Agents. AJNR Am J Neuroradiol 2018; 39:1597-1603. [PMID: 30139752 DOI: 10.3174/ajnr.a5751] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2018] [Accepted: 06/20/2018] [Indexed: 11/07/2022]
Abstract
BACKGROUND AND PURPOSE Dose-dependent association between hyperintensity in deep brain structures on unenhanced T1WIs and gadolinium-based contrast agent administrations has been demonstrated with subsequent histopathological confirmation of gadolinium deposition. Our aim was to determine whether greater exposure to linear gadolinium-based contrast agent administration is associated with higher signal intensity in deep brain structures on unenhanced T1-weighted MR imaging. Secondary objective was to compare signal intensity differences between ionic and nonionic linear gadolinium-based contrast agents. MATERIALS AND METHODS Subjects with secondary-progressive MS originally enrolled in a multicenter clinical trial were studied retrospectively. Eighty subjects (high-exposure cohort) received 9 linear gadolinium-based contrast agent administrations (30 nonionic/50 ionic) between week -4 and year 1 and a tenth administration by year 2. One hundred fifteen subjects (low-exposure cohort) received 2 administrations (40 nonionic/75 ionic) between week -4 and year 1 and a third administration by year 2. Signal intensities were measured on unenhanced T1WIs by placing sample-points on the dentate nucleus, globus pallidus, caudate, thalamus, pons, and white matter, and they were normalized using the following ratios: dentate/pons, globus pallidus/white matter, caudate/white matter, and thalamus/white matter. RESULTS Between week -4 and year 1, subjects in the high-exposure cohort showed increased signal intensity ratios in all regions (P < .01), while the low-exposure cohort showed only an increase in the dentate nucleus (P = .003). Between years 1 and 2, when both cohorts received only 1 additional gadolinium-based contrast agent, no significant changes were observed. In the high-exposure cohort, significantly higher changes in signal intensity ratios were observed in subjects receiving linear nonionic than in those receiving linear ionic gadolinium-based contrast agents. CONCLUSIONS Hyperintensity in deep brain structures from gadolinium deposition is related to the number of doses and the type of linear gadolinium-based contrast agent (nonionic greater than ionic) administration.
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Affiliation(s)
- H Kang
- From the Department of Radiology (H.K., M.L., R.T., S.K., D.K.B.L.)
| | - M Hii
- University of British Columbia MS/MRI Research Group (M.H., R.T., A.R., A.T., S.K., D.K.B.L.)
| | - M Le
- From the Department of Radiology (H.K., M.L., R.T., S.K., D.K.B.L.)
| | - R Tam
- From the Department of Radiology (H.K., M.L., R.T., S.K., D.K.B.L.).,University of British Columbia MS/MRI Research Group (M.H., R.T., A.R., A.T., S.K., D.K.B.L.)
| | - A Riddehough
- University of British Columbia MS/MRI Research Group (M.H., R.T., A.R., A.T., S.K., D.K.B.L.)
| | - A Traboulsee
- University of British Columbia MS/MRI Research Group (M.H., R.T., A.R., A.T., S.K., D.K.B.L.).,Department of Medicine and Division of Neurology (A.T., S.K., D.K.B.L.)
| | - S Kolind
- From the Department of Radiology (H.K., M.L., R.T., S.K., D.K.B.L.).,University of British Columbia MS/MRI Research Group (M.H., R.T., A.R., A.T., S.K., D.K.B.L.).,Department of Medicine and Division of Neurology (A.T., S.K., D.K.B.L.).,Department of Physics and Astronomy (S.K.), University of British Columbia, Vancouver, British Columbia, Canada
| | - M S Freedman
- Department of Medicine and Division of Neurology (M.S.F.), University of Ottawa and the Ottawa Hospital Research Institute, Ottawa, Canada
| | - D K B Li
- From the Department of Radiology (H.K., M.L., R.T., S.K., D.K.B.L.).,University of British Columbia MS/MRI Research Group (M.H., R.T., A.R., A.T., S.K., D.K.B.L.).,Department of Medicine and Division of Neurology (A.T., S.K., D.K.B.L.)
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Wiemers PD, Marney L, White N, Bough G, Hustig A, Tan W, Cheng CS, Kang D, Yadav S, Tam R, Fraser JF. Comorbidities and Ventricular Dysfunction Drive Excess Mid-Term Morbidity in an Indigenous Australian Coronary Revascularisation Cohort. Heart Lung Circ 2018; 28:874-883. [PMID: 29843975 DOI: 10.1016/j.hlc.2018.04.285] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2017] [Revised: 12/16/2017] [Accepted: 04/10/2018] [Indexed: 10/17/2022]
Abstract
BACKGROUND There is a paucity of data in regards to longer term morbidity outcomes in Indigenous Australian patients undergoing coronary artery bypass grafting (CABG). No comparative data on re-infarction, stroke or reintervention rates exist. Outcome data following percutaneous coronary intervention (PCI) is also extremely limited. Addressing this gap in knowledge forms the major aim of our study. METHODS This was a single centre cohort study conducted at the Townsville Hospital, Australia which provides tertiary adult cardiac surgical services to the northern parts of the state of Queensland. It incorporated consecutive patients (n=350) undergoing isolated CABG procedures, 2008-2010, 20.9% (73/350) of whom were Indigenous Australians. The main outcome measures were major adverse cardiac or cerebrovascular events (MACCE) at mid-term follow-up (mean 38.9 months). RESULTS The incidence of MACCE among Indigenous Australian patients was approximately twice that of non-Indigenous patients at mid-term follow-up (36.7% vs. 18.6%; p=0.005; OR 2.525 (1.291-4.880)). Following adjustment for preoperative and operative variables, Indigenous Australian status itself was not significantly associated with MACCE (AOR 1.578 (0.637-3.910)). Significant associations with MACCE included renal impairment (AOR 2.198 (1.010-4.783)) and moderate-severe left ventricular impairment (AOR 3.697 (1.820-7.508)). An association between diabetes and MACCE failed to reach statistical significance (AOR 1.812 (0.941-3.490)). CONCLUSIONS Indigenous Australians undergoing CABG suffer an excess of MACCE when followed-up in the longer term. High rates of comorbidities in the Indigenous Australian population likely play an aetiological role.
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Affiliation(s)
- Paul D Wiemers
- Department of Cardiothoracic Surgery, The Townsville Hospital, Townsville, Qld, Australia; University of Queensland School of Medicine, Brisbane, Qld, Australia; Royal Brisbane & Women's Hospital, Herston, Qld, Australia.
| | - Lucy Marney
- Department of Cardiothoracic Surgery, The Townsville Hospital, Townsville, Qld, Australia
| | - Nicole White
- ARC Centre of Excellence for Mathematical & Statistical Frontiers (ACEMS), School of Mathematical Sciences, Science and Engineering Faculty, Queensland University of Technology, Brisbane, Qld, Australia
| | - Georgina Bough
- Department of Cardiothoracic Surgery, The Townsville Hospital, Townsville, Qld, Australia
| | - Alistair Hustig
- Department of Cardiothoracic Surgery, The Townsville Hospital, Townsville, Qld, Australia
| | - Wei Tan
- Department of Cardiothoracic Surgery, The Townsville Hospital, Townsville, Qld, Australia
| | - Ching-Siang Cheng
- Department of Cardiothoracic Surgery, The Townsville Hospital, Townsville, Qld, Australia
| | - Dong Kang
- Department of Cardiothoracic Surgery, The Townsville Hospital, Townsville, Qld, Australia
| | - Sumit Yadav
- Department of Cardiothoracic Surgery, The Townsville Hospital, Townsville, Qld, Australia
| | - Robert Tam
- Department of Cardiothoracic Surgery, The Townsville Hospital, Townsville, Qld, Australia; James Cook University, College of Medicine and Dentistry, Townsville, Qld, Australia
| | - John F Fraser
- University of Queensland School of Medicine, Brisbane, Qld, Australia; Critical Care Research Group, The Prince Charles Hospital, Brisbane, Qld, Australia
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Wiemers PD, Marney L, Yadav S, Tam R, Fraser JF. An Overview of Indigenous Australian Disadvantage in Terms of Ischaemic Heart Disease. Heart Lung Circ 2018; 27:1274-1284. [PMID: 29929920 DOI: 10.1016/j.hlc.2018.03.003] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2017] [Revised: 10/18/2017] [Accepted: 03/01/2018] [Indexed: 12/19/2022]
Abstract
BACKGROUND Indigenous Australians experience poorer health outcomes than non-Indigenous Australians and a significant life expectancy gap exists. Ischaemic heart disease (IHD) represents the leading specific cause of death in Indigenous Australians and is a significant, if not the most significant, contributor to the mortality gap. With this narrative review we aim to describe the burden of IHD within the Indigenous Australian community and explore the factors driving this disparity. METHODS A broad search of the literature was undertaken utilising an electronic search of the PubMed database along with national agency databases-the Australian Institute of Health and Welfare (AIHW) and the Australian Bureau of Statistics (ABS). RESULTS A complex interplay between multiple factors contributes to the excess burden of IHD in the Indigenous Australian population: CONCLUSIONS: In terms of IHD, Indigenous Australians experience disadvantage at multiple stages of the disease process. Ongoing efforts are needed to continue to inform clinicians of both this disadvantage and strategies to assist negating it. Further research is needed to develop evidence based practices which may help reduce this disparity in outcomes.
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Affiliation(s)
- Paul D Wiemers
- Department of Cardiothoracic Surgery, The Townsville Hospital, Townsville, Qld, Australia; University of Queensland School of Medicine, Brisbane, Qld, Australia; Royal Brisbane & Women's Hospital, Herston, Qld, Australia.
| | - Lucy Marney
- Department of Cardiothoracic Surgery, The Townsville Hospital, Townsville, Qld, Australia
| | - Sumit Yadav
- Department of Cardiothoracic Surgery, The Townsville Hospital, Townsville, Qld, Australia
| | - Robert Tam
- Department of Cardiothoracic Surgery, The Townsville Hospital, Townsville, Qld, Australia; James Cook University, College of Medicine and Dentistry, Townsville, Qld, Australia
| | - John F Fraser
- University of Queensland School of Medicine, Brisbane, Qld, Australia; Critical Care Research Group, The Prince Charles Hospital, The University of Queensland, Brisbane, Qld, Australia
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Wei R, Lunn SE, Tam R, Gust SL, Classen B, Kerr PM, Plane F. Vasoconstrictor stimulus determines the functional contribution of myoendothelial feedback to mesenteric arterial tone. J Physiol 2018; 596:1181-1197. [PMID: 29411383 DOI: 10.1113/jp274797] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2017] [Accepted: 01/17/2018] [Indexed: 12/16/2022] Open
Abstract
KEY POINTS In isolated resistance arteries, endothelial modulation of vasoconstrictor responses to α1 -adrenoceptor agonists occurs via a process termed myoendothelial feedback: localized inositol trisphosphate (InsP3 )-dependent Ca2+ transients activate intermediate conductance Ca2+ -activated K+ (IKCa ) channels, hyperpolarizing the endothelial membrane potential to limit further reductions in vessel diameter. We demonstrate that IKCa channel-mediated myoendothelial feedback limits responses of isolated mesenteric arteries to noradrenaline and nerve stimulation, but not to the thromboxane A2 mimetic U46619 or to increases in intravascular pressure. In contrast, in the intact mesenteric bed, although responses to exogenous noradrenaline were limited by IKCa channel-mediated myoendothelial feedback, release of NO and activation of endothelial small conductance Ca2+ -activated K+ (SKCa ) channels in response to increases in shear stress appeared to be the primary mediators of endothelial modulation of vasoconstriction. We propose that (1) the functional contribution of myoendothelial feedback to arterial tone is determined by the nature of the vasoconstrictor stimulus, and (2) although IKCa channel-mediated myoendothelial feedback may contribute to local control of arterial diameter, in the intact vascular bed, increases in shear stress may be the major stimulus for engagement of the endothelium during vasoconstriction. ABSTRACT Constriction of isolated resistance arteries in response to α1 -adrenoceptor agonists is limited by reciprocal engagement of inhibitory endothelial mechanisms via myoendothelial feedback. In the current model of feedback, agonist stimulation of smooth muscle cells results in localized InsP3 -dependent Ca2+ transients that activate endothelial IKCa channels. The subsequent hyperpolarization of the endothelial membrane potential then feeds back to the smooth muscle to limit further reductions in vessel diameter. We hypothesized that the functional contribution of InsP3 -IKCa channel-mediated myoendothelial feedback to limiting arterial diameter may be influenced by the nature of the vasoconstrictor stimulus. To test this hypothesis, we investigated the functional role of myoendothelial feedback in modulating responses of rat mesenteric resistance arteries to the adrenoceptor agonist noradrenaline, the thromboxane A2 mimetic U46619, increases in intravascular pressure and stimulation of perivascular sympathetic nerves. In isolated arteries, responses to noradrenaline and stimulation of sympathetic nerves, but not to U46619 and increases in intravascular pressure, were modulated by IKCa channel-dependent myoendothelial feedback. In the intact mesenteric bed perfused under conditions of constant flow, responses to exogenous noradrenaline were modulated by myoendothelial feedback, but shear stress-induced release of NO and activation of endothelial SKCa channels appeared to be the primary mediators of endothelial modulation of vasoconstriction to agonists and nerve stimulation. Thus, we propose that myoendothelial feedback may contribute to local control of diameter within arterial segments, but at the level of the intact vascular bed, increases in shear stress may be the major stimulus for engagement of the endothelium during vasoconstriction.
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Affiliation(s)
- R Wei
- Department of Pharmacology, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, T6G 2H7, Canada
| | - S E Lunn
- Department of Pharmacology, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, T6G 2H7, Canada
| | - R Tam
- Department of Pharmacology, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, T6G 2H7, Canada
| | - S L Gust
- Department of Pharmacology, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, T6G 2H7, Canada
| | - B Classen
- Department of Pharmacology, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, T6G 2H7, Canada
| | - P M Kerr
- Department of Nursing Science, Faculty of Nursing, MacEwan University, Edmonton, Alberta, T5J 4S2, Canada
| | - F Plane
- Department of Pharmacology, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, T6G 2H7, Canada.,Cardiovascular Research Centre, University of Alberta, Edmonton, Alberta, T6G 2H7, Canada
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Yong M, Smith S, O’Dempsey S, Grant R, Wiemers P, Saxena P, Tam R, Iyer A, Yadav S. Current Outcomes of Valvular Surgery for Indigenous Australians With Rheumatic Heart Disease: A Single-centre Experience. Heart Lung Circ 2018. [DOI: 10.1016/j.hlc.2018.06.829] [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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10
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Traboulsee A, Li D, Tam R, Zhao G, Riddehough A, Fang J, Dangond F, Kappos L. Subcutaneous interferon β-1a three times weekly and the natural evolution of gadolinium-enhancing lesions into chronic black holes in relapsing and progressive multiple sclerosis: Analysis of PRISMS and SPECTRIMS trials. Mult Scler J Exp Transl Clin 2017; 3:2055217317745340. [PMID: 29276624 PMCID: PMC5734469 DOI: 10.1177/2055217317745340] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [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] [Received: 03/06/2017] [Accepted: 11/03/2017] [Indexed: 11/17/2022] Open
Abstract
Background Evolution of gadolinium-enhancing lesions into chronic black holes (CBH) may be reduced by interferon (IFN) therapy. Objective The objective of this paper is to assess the effect of IFN β-1a and placebo on CBH evolution and disability in patients with relapsing–remitting multiple sclerosis (RRMS), as well as CBH evolution in patients with secondary progressive multiple sclerosis (SPMS). Methods A post hoc, exploratory analysis of patients with RRMS and SPMS with monthly MRI scans (months –1 to 9) from two separate placebo-controlled clinical trials of IFN β-1a was conducted. Results In RRMS patients, the risk of ≥1 evolved CBH was lower for IFN β-1a versus placebo (odds ratio 0.42; p = 0.024); volume of newly evolved CBH was numerically reduced. A numerically higher proportion of patients with ≥1 evolving CBH vs no evolving CBH had confirmed three-month disability progression (four-year rate 55.8% vs 43.1%, respectively). Proportion of lesions evolving into CBH (patient level: 34.7% vs 12.6%, p < 0.0001; lesion level: 28.8% vs 11.0%, p < 0.0001) and evolved CBH volume (median 33.5 mm3 (Quartile 1, 0.0; Quartile 3, 173.4) vs 0.0 mm3 (0.0; 52.4); p = 0.0008) was higher for SPMS than RRMS patients treated with IFN β-1a. Conclusion In RRMS, IFN β-1a significantly decreased the proportion of new T1 Gd+ lesions evolving into CBH and the risk of developing a CBH. In patients with SPMS, more lesions develop to CBH, indicating reduced repair capacity, and the natural history of lesion development appears to be unaffected by IFN β-1a treatment.
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Affiliation(s)
- A Traboulsee
- Department of Medicine, Faculty of Medicine, University of British Columbia, Canada
| | - Dkb Li
- Department of Medicine, Faculty of Medicine, University of British Columbia, Canada
| | - R Tam
- University of British Columbia, Canada
| | - G Zhao
- Division of Neurology, University of British Columbia, Canada
| | - A Riddehough
- Division of Neurology, University of British Columbia, Canada
| | | | | | - L Kappos
- Departments of Medicine, Biomedicine, Clinical Research and Biomedical Engineering, University Hospital Basel, Switzerland
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Traboulsee A, Machan L, Girard M, Raymond J, Vosoughi R, Hardy B, Edmond F, Bone J, Gariepy J, Tam R, Klass D, Isserow S, Rauscher A, Sadovnick A, Li D, Illes J, Siskin G. Venoplasty of chronic cerebral spinal venous insufficiency to improve MS patient reported outcomes is not superior to sham treatment at week 2 or week 12. J Neurol Sci 2017. [DOI: 10.1016/j.jns.2017.08.3012] [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] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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12
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Barha C, Dao E, Best J, Hsiung R, Tam R, Liu-Ambrose T. SEX-DEPENDENT EFFECT OF EXERCISE ON BRAIN HEALTH IN OLDER ADULTS WITH VCI. Innov Aging 2017. [DOI: 10.1093/geroni/igx004.840] [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] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- C. Barha
- Physical Therapy, University of British Columbia, Burnaby, British Columbia, Canada
| | - E. Dao
- Physical Therapy, University of British Columbia, Burnaby, British Columbia, Canada
| | - J. Best
- Physical Therapy, University of British Columbia, Burnaby, British Columbia, Canada
| | - R.G. Hsiung
- Physical Therapy, University of British Columbia, Burnaby, British Columbia, Canada
| | - R. Tam
- Physical Therapy, University of British Columbia, Burnaby, British Columbia, Canada
| | - T. Liu-Ambrose
- Physical Therapy, University of British Columbia, Burnaby, British Columbia, Canada
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Dao E, Best J, Hsiung R, Sossi V, Jacova C, Tam R, Liu-Ambrose T. EFFECTS OF AMYLOID ON CHANGES IN COGNITIVE AND PHYSICAL FUNCTION IN VASCULAR COGNITIVE IMPAIRMENT. Innov Aging 2017. [DOI: 10.1093/geroni/igx004.656] [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] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Affiliation(s)
- E. Dao
- University of British Columbia, Vancouver, British Columbia, Canada,
| | - J. Best
- University of British Columbia, Vancouver, British Columbia, Canada,
| | - R.G. Hsiung
- University of British Columbia, Vancouver, British Columbia, Canada,
| | - V. Sossi
- University of British Columbia, Vancouver, British Columbia, Canada,
| | - C. Jacova
- Pacific University, Forest Grove, Oregon
| | - R. Tam
- University of British Columbia, Vancouver, British Columbia, Canada,
| | - T. Liu-Ambrose
- University of British Columbia, Vancouver, British Columbia, Canada,
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Russell EA, Walsh WF, Reid CM, Tran L, Brown A, Bennetts JS, Baker RA, Tam R, Maguire GP. Outcomes after mitral valve surgery for rheumatic heart disease. Heart Asia 2017; 9:e010916. [PMID: 29467839 DOI: 10.1136/heartasia-2017-010916] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/12/2017] [Revised: 05/03/2017] [Accepted: 05/04/2017] [Indexed: 11/03/2022]
Abstract
Objective To further the understanding of the factors influencing outcome following rheumatic heart disease (RHD) related mitral valve surgery, which globally remains an important cause of heart disease and a particular problem in Indigenous Australians. Methods The Australian Cardiac Surgery Database was utilised to assess outcomes following mitral valve repair and replacement for RHD and non-RHD valve disease. The association with aetiology, demographics, comorbidities, preoperative status and operative procedure was evaluated. Results Mitral valve repairs and replacements undertaken in Australia were analysed from 119 and 1078 RHD surgical procedures and 3279 and 2400 non-RHD procedures, respectively. RHD mitral valve repair, compared with replacement, resulted in a slightly shorter hospital stay and more reoperation for valve dysfunction, but no difference in 30-day survival. In unadjusted survival analysis to 5 years, RHD mitral valve repair and replacement were no different (HR 0.86, 95% CI 0.4 to 1.7), non-RHD repair was superior to replacement (HR 1.7, 95% CI 1.4 to 2.0), RHD and non-RHD repair were no different (HR 0.9, 95% CI 0.5 to 1.7), and RHD replacement was superior to non-RHD (HR 1.5, 95% CI 1.2 to 1.9). None of these differences persisted in adjusted analyses and there was no difference in long-term survival for Indigenous Australians. Conclusion In this large prospective cohort study we have demonstrated that adjusted long-term survival following RHD mitral valve repair surgery in Australia is no different to replacement and no different to non-RHD. Interpretation of valve surgery outcome requires careful consideration of patient factors that may also influence survival.
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Affiliation(s)
- E Anne Russell
- Clinical Research Domain, Baker Heart and Diabetes Institute, Melbourne, Victoria, Australia.,School of Epidemiology and Preventive Medicine, Monash University, Melbourne, Victoria, Australia
| | - Warren F Walsh
- Department of Cardiology, Prince of Wales Hospital, Randwick, NSW, Australia
| | - Christopher M Reid
- School of Epidemiology and Preventive Medicine, Monash University, Melbourne, Victoria, Australia.,School of Public Health, Curtin University, Perth, WA, Australia
| | - Lavinia Tran
- School of Epidemiology and Preventive Medicine, Monash University, Melbourne, Victoria, Australia
| | - Alex Brown
- Wardliparingga Aboriginal Research Unit, South Australia Health and Medical Research Institute, Adelaide, Australia.,School of Population Health, University of South Australia, Adelaide, South Australia
| | - Jayme S Bennetts
- Department of Cardiac and Thoracic Surgery, Flinders Medical Centre, Adelaide, Australia.,Department of Surgery, School of Medicine, Flinders University, Adelaide, South Australia, Australia
| | - Robert A Baker
- Department of Cardiac and Thoracic Surgery, Flinders Medical Centre, Adelaide, Australia
| | - Robert Tam
- Department of Cardiothoracic Surgery, The Townsville Hospital, Townsville, Queensland, Australia
| | - Graeme P Maguire
- Clinical Research Domain, Baker Heart and Diabetes Institute, Melbourne, Victoria, Australia.,School of Epidemiology and Preventive Medicine, Monash University, Melbourne, Victoria, Australia
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Russell EA, Walsh WF, Tran L, Tam R, Reid CM, Brown A, Bennetts JS, Baker RA, Maguire GP. The burden and implications of preoperative atrial fibrillation in Australian heart valve surgery patients. Int J Cardiol 2017; 227:100-105. [DOI: 10.1016/j.ijcard.2016.11.070] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/13/2016] [Accepted: 11/05/2016] [Indexed: 10/20/2022]
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Grant R, McGiffin D, Tam R, Yadav S, Dev H, Saxena P. The Value of Cardiac Dissection Workshop to Medical Students. Heart Lung Circ 2017. [DOI: 10.1016/j.hlc.2017.03.048] [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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Russell EA, Baker RA, Bennetts JS, Brown A, Reid CM, Tam R, Tran L, Walsh WF, Maguire GP. Case load and valve surgery outcome in Australia. Int J Cardiol 2016; 221:144-51. [PMID: 27400312 DOI: 10.1016/j.ijcard.2016.06.179] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [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: 04/20/2016] [Accepted: 06/24/2016] [Indexed: 11/27/2022]
Abstract
BACKGROUND In Australia it has been suggested that heart valve surgery, particularly for rheumatic heart disease (RHD), should be consolidated in higher volume centres. International studies of cardiac surgery suggest large volume centres have superior outcomes. However the effect of site and surgeon case load on longer term outcomes for valve surgery has not been investigated. METHODS The Australian and New Zealand Society of Cardiac and Thoracic Surgeons Cardiac Surgery Database was analysed. The adjusted association between both average annual site and surgeon case load on short term complications and short and long-term survival was determined. RESULTS Outcomes associated with 20,116 valve procedures at 25 surgical sites and by 93 surgeons were analysed. Overall adjusted analysis showed increasing site and surgeon case load was associated with longer ventilation, less reoperation and more anticoagulant complications. Increasing surgeon case load was also associated with less acute kidney injury. Adjusted 30-day mortality was not associated with site or surgeon case load. There was no consistent relationship between increasing site case load and long term survival. The association between surgeon case load and outcome demonstrated poorer adjusted survival in the highest volume surgeon group. CONCLUSIONS In this Australian study, the adjusted association between surgeon and site case load was not simple or consistent. Overall larger volume sites or surgeons did not have superior outcomes. Mandating a particular site case load level for valve surgery or a minimum number of procedures for individual surgeons, in an Australian context, cannot be supported by these findings.
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Affiliation(s)
| | - Robert A Baker
- School of Epidemiology and Preventive Medicine, Monash University, Melbourne, Victoria, Australia; Department of Cardiac and Thoracic Surgery, Flinders Medical Centre, Adelaide, SA.
| | - Jayme S Bennetts
- Department of Surgery, School of Medicine, Flinders University, Adelaide, SA, Australia; Department of Cardiac and Thoracic Surgery, Flinders Medical Centre, Adelaide, SA, Australia.
| | - Alex Brown
- Wardliparingga Aboriginal Research Unit, South Australia Health and Medical Research Institute, Adelaide, SA, Australia; School of Population Health, University of South Australia, Adelaide, SA, Australia.
| | - Christopher M Reid
- School of Public Health, Curtin University, Perth, WA, Australia; School of Epidemiology and Preventive Medicine, Monash University, Melbourne, Victoria, Australia.
| | - Robert Tam
- Department of Cardiothoracic Surgery, Townsville, Hospital, Queensland, Australia.
| | - Lavinia Tran
- School of Epidemiology and Preventive Medicine, Monash University, Melbourne, Victoria, Australia
| | | | - Graeme P Maguire
- Baker IDI, Melbourne, Victoria, Australia; School of Medicine, James Cook University, Cairns, Queensland, Australia; School of Epidemiology and Preventive Medicine, Monash University, Melbourne, Victoria, Australia.
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Affiliation(s)
- Pankaj Saxena
- Department of Cardiac Surgery, Prince Charles Hospital, Rode Road, Chermside, 4032, Australia
| | - Robert Tam
- Department of Cardiac Surgery, Prince Charles Hospital, Rode Road, Chermside, 4032, Australia
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Russell EA, Tran L, Baker RA, Bennetts JS, Brown A, Reid CM, Tam R, Walsh WF, Maguire GP. A review of outcome following valve surgery for rheumatic heart disease in Australia. BMC Cardiovasc Disord 2015; 15:103. [PMID: 26399240 PMCID: PMC4580994 DOI: 10.1186/s12872-015-0094-1] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2015] [Accepted: 09/14/2015] [Indexed: 11/15/2022] Open
Abstract
Background Globally, rheumatic heart disease (RHD) remains an important cause of heart disease. In Australia it particularly affects younger Indigenous and older non-Indigenous Australians. Despite its impact there is limited understanding of the factors influencing outcome following surgery for RHD. Methods The Australian and New Zealand Society of Cardiac and Thoracic Surgeons Cardiac Surgery Database was analysed to assess outcomes following surgical procedures for RHD and non-RHD valvular disease. The association with demographics, co-morbidities, pre-operative status, valve(s) affected and operative procedure was evaluated. Results Outcome of 1384 RHD and 15843 non-RHD valve procedures was analysed. RHD patients had longer ventilation, experienced fewer strokes and had more readmissions to hospital and anticoagulant complications. Mortality following RHD surgery at 30 days was 3.1 % (95 % CI 2.2 – 4.3), 5 years 15.3 % (11.7 – 19.5) and 10 years 25.0 % (10.7 – 44.9). Mortality following non-RHD surgery at 30 days was 4.3 % (95 % CI 3.9 - 4.6), 5 years 17.6 % (16.4 - 18.9) and 10 years 39.4 % (33.0 - 46.1). Factors independently associated with poorer longer term survival following RHD surgery included older age (OR1.03/additional year, 95 % CI 1.01 – 1.05), concomitant diabetes (OR 1.7, 95 % CI 1.1 – 2.5) and chronic kidney disease (1.9, 1.2 – 2.9), longer invasive ventilation time (OR 1.7 if greater than median value, 1.1– 2.9) and prolonged stay in hospital (1.02/additional day, 1.01 – 1.03). Survival in Indigenous Australians was comparable to that seen in non-Indigenous Australians. Conclusion In a large prospective cohort study we have demonstrated survival following RHD valve surgery in Australia is comparable to earlier studies. Patients with diabetes and chronic kidney disease, were at particular risk of poorer long-term survival. Unlike earlier studies we did not find pre-existing atrial fibrillation, being an Indigenous Australian or the nature of the underlying valve lesion were independent predictors of survival.
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Affiliation(s)
- E Anne Russell
- Baker IDI, Melbourne, VIC, 3004, Australia. .,School of Epidemiology and Preventive Medicine, Monash University, Melbourne, VIC, Australia.
| | - Lavinia Tran
- School of Epidemiology and Preventive Medicine, Monash University, Melbourne, VIC, Australia.
| | - Robert A Baker
- Department of Cardiac and Thoracic Surgery, Flinders Medical Centre, Adelaide, South Australia.
| | - Jayme S Bennetts
- Department of Cardiac and Thoracic Surgery, Flinders Medical Centre, Adelaide, South Australia. .,Department of Surgery, School of Medicine, Flinders University, Adelaide, South Australia.
| | - Alex Brown
- Wardliparingga Aboriginal Research Unit, South Australia Health and Medical Research Institute, Adelaide, South Australia. .,School of Population Health, University of South Australia, Adelaide, South Australia.
| | - Christopher M Reid
- School of Epidemiology and Preventive Medicine, Monash University, Melbourne, VIC, Australia. .,School of Public Health, Curtin University, Perth, Western Australia.
| | - Robert Tam
- Director of Surgery, Department of Cardiothoracic Surgery, Townsville Hospital, Queensland, Australia.
| | | | - Graeme P Maguire
- Baker IDI, Melbourne, VIC, 3004, Australia. .,School of Epidemiology and Preventive Medicine, Monash University, Melbourne, VIC, Australia. .,School of Medicine, James Cook University, Cairns, QLD, Australia.
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20
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MacMillan EL, Tam R, Zhao Y, Vavasour IM, Li DKB, Oger J, Freedman MS, Kolind SH, Traboulsee AL. Progressive multiple sclerosis exhibits decreasing glutamate and glutamine over two years. Mult Scler 2015; 22:112-6. [DOI: 10.1177/1352458515586086] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2014] [Accepted: 04/11/2015] [Indexed: 11/17/2022]
Abstract
Background: Few biomarkers of progressive multiple sclerosis (MS) are sensitive to change within the two-year time frame of a clinical trial. Objective: To identify biomarkers of MS disease progression with magnetic resonance spectroscopy (MRS) in secondary progressive MS (SPMS). Methods: Forty-seven SPMS subjects were scanned at baseline and annually for two years. Concentrations of N-acetylaspartate, total creatine, total choline, myo-inositol, glutamate, glutamine, and the sum glutamate+glutamine were measured in a single white matter voxel. Results: Glutamate and glutamine were the only metabolites to show an effect with time: with annual declines of (95% confidence interval): glutamate −4.2% (−6.2% to −2.2%, p < 10−4), glutamine −7.3% (−11.8% to −2.9%, p = 0.003), and glutamate+glutamine −5.2% (−7.6% to −2.8%, p < 10−4). Metabolite rates of change were more apparent than changes in clinical scores or brain atrophy measures. Conclusions: The high rates of change of both glutamate and glutamine over two years suggest they are promising new biomarkers of MS disease progression.
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Affiliation(s)
- EL MacMillan
- Division of Neurology, Faculty of Medicine, The University of British Columbia, Vancouver, Canada
| | - R Tam
- Department of Radiology, Faculty of Medicine, The University of British Columbia, Vancouver, Canada/UBC MS/MRI Research Group, The University of British Columbia, Vancouver, Canada
| | - Y Zhao
- UBC MS/MRI Research Group, The University of British Columbia, Vancouver, Canada
| | - IM Vavasour
- Department of Radiology, Faculty of Medicine, The University of British Columbia, Vancouver, Canada
| | - DKB Li
- Department of Radiology, Faculty of Medicine, The University of British Columbia, Vancouver, Canada/UBC MS/MRI Research Group, The University of British Columbia, Vancouver, Canada
| | - J Oger
- Division of Neurology, Faculty of Medicine, The University of British Columbia, Vancouver, Canada
| | - MS Freedman
- Department of Neurology, Faculty of Medicine, The University of Ottawa, Canada
| | - SH Kolind
- Division of Neurology, Faculty of Medicine, The University of British Columbia, Vancouver, Canada
| | - AL Traboulsee
- Division of Neurology, Faculty of Medicine, The University of British Columbia, Vancouver, Canada
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Russell E, Maguire G, Tran L, Reid C, Walsh W, Brown A, Baker R, Tam R, Bennetts J. Does annual site-specific caseload influence valve surgical outcome in Australia? Heart Lung Circ 2015. [DOI: 10.1016/j.hlc.2015.06.695] [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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Kapoun A, O'Reilly E, Cohn A, Bendell J, Smith L, Strickler J, Gluck W, Liu Y, Wallace B, Tam R, Cancilla B, Brunner A, Hill D, Zhou L, Dupont J, Zhang C, Wang M. 465 Biomarker analysis in Phase 1b study of anti-cancer stem cell antibody Tarextumab (TAR) in combination with nab-paclitaxel and gemcitabine (Nab-P+Gem) demonstrates pharmacodynamic (PD) modulation of the Notch pathway in patients (pts) with untreated metastatic pancreatic cancer (mPC). Eur J Cancer 2014. [DOI: 10.1016/s0959-8049(14)70591-x] [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: 11/17/2022]
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Russell EA, Tran L, Baker RA, Bennetts JS, Brown A, Reid CM, Tam R, Walsh WF, Maguire GP. A review of valve surgery for rheumatic heart disease in Australia. BMC Cardiovasc Disord 2014; 14:134. [PMID: 25274483 PMCID: PMC4196004 DOI: 10.1186/1471-2261-14-134] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2014] [Accepted: 09/23/2014] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Globally, rheumatic heart disease (RHD) remains an important cause of heart disease. In Australia it particularly affects older non-Indigenous Australians and Aboriginal Australians and/or Torres Strait Islander peoples. Factors associated with the choice of treatment for advanced RHD remain variable and poorly understood. METHODS The Australian and New Zealand Society of Cardiac and Thoracic Surgeons Cardiac Surgery Database was analysed. Demographics, co-morbidities, pre-operative status and valve(s) affected were collated and associations with management assessed. RESULTS Surgical management of 1384 RHD and 15843 non-RHD valve procedures was analysed. RHD patients were younger, more likely to be female and Indigenous Australian, to have atrial fibrillation (AF) and previous percutaneous balloon valvuloplasty (PBV). Surgery was performed on one valve in 64.5%, two valves in 30.0% and three valves in 5.5%. Factors associated with receipt of mechanical valves in RHD were AF (OR 2.69) and previous PBV (OR 1.98) and valve surgery (OR 3.12). Predictors of valve repair included being Indigenous (OR 3.84) and having fewer valves requiring surgery (OR 0.10). Overall there was a significant increase in the use of mitral bioprosthetic valves over time. CONCLUSIONS RHD valve surgery is more common in young, female and Indigenous patients. The use of bioprosthetic valves in RHD is increasing. Given many patients are female and younger, the choice of valve surgery and need for anticoagulation has implications for future management of RHD and related morbidity, pregnancy and lifestyle plans.
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Affiliation(s)
- Elizabeth Anne Russell
- />Baker IDI Central Australia, PO Box 1294, Alice Springs, NT 0811 Australia
- />School of Epidemiology and Preventive Medicine, Monash University, Melbourne, Victoria Australia
| | - Lavinia Tran
- />School of Epidemiology and Preventive Medicine, Monash University, Melbourne, Victoria Australia
| | - Robert A Baker
- />Department of Cardiac and Thoracic Surgery, Flinders Medical Centre, Adelaide, SA Australia
| | - Jayme S Bennetts
- />Department of Cardiac and Thoracic Surgery, Flinders Medical Centre, Adelaide, SA Australia
- />Department of Surgery, School of Medicine, Flinders University, Adelaide, SA Australia
| | - Alex Brown
- />Wardliparingga Aboriginal Research Unit, South Australia Health and Medical Research Institute, Adelaide, SA Australia
- />School of Population Health, University of South Australia, Adelaide, SA Australia
| | - Christopher Michael Reid
- />School of Epidemiology and Preventive Medicine, Monash University, Melbourne, Victoria Australia
| | - Robert Tam
- />Department of Cardiothoracic Surgery, The Townsville Hospital, Queensland, Australia
| | | | - Graeme Paul Maguire
- />Baker IDI Central Australia, PO Box 1294, Alice Springs, NT 0811 Australia
- />School of Epidemiology and Preventive Medicine, Monash University, Melbourne, Victoria Australia
- />School of Medicine, James Cook University, Cairns, Queensland Australia
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Pesek JJ, Matyska MT, Williamser EJ, Tam R. Variable-temperature, solid-state NMR studies of bonded liquid crystal stationary phases for HPLC. Chromatographia 2014. [DOI: 10.1007/bf02688044] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Wiemers P, Marney L, White N, Bough, Hustig A, Tan W, Cheng CS, Kang D, Yadav S, Fraser J, Tam R. Midterm Results of Coronary Artery Bypass Grafting in an Australian Indigenous Population. Heart Lung Circ 2014. [DOI: 10.1016/j.hlc.2013.10.019] [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: 10/25/2022]
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Wiemers P, Marney L, Muller R, Brandon M, Kuchu P, Kuhlar K, Uchime C, Kang D, White N, Greenup R, Fraser JF, Yadav S, Tam R. Cardiac surgery in Indigenous Australians--how wide is 'the gap'? Heart Lung Circ 2013; 23:265-72. [PMID: 24321647 DOI: 10.1016/j.hlc.2013.09.002] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2012] [Revised: 08/11/2013] [Accepted: 09/07/2013] [Indexed: 10/26/2022]
Abstract
BACKGROUND Cardiovascular disease remains the leading cause of mortality in the Indigenous Australian population. Limited research exists in regards to cardiac surgery in the Aboriginal and Torres Strait Islander (ATSI) population. We aimed to investigate risk profiles, surgical pathologies, surgical management and short term outcomes in a contemporary group of patients. METHODS Variables were assessed for 557 consecutive patients who underwent surgery at our institution between August 2008 and March 2010. RESULTS 19.2% (107/557) of patients were of Indigenous origin. ATSI patients were significantly younger at time of surgery (mean age 54.1±13.23 vs. 63.1±12.46; p=<0.001) with higher rates of preventable risk factors. Rheumatic heart disease (RHD) was the dominant valvular pathology observed in the Indigenous population. Significantly higher rates of left ventricular impairment and more diffuse coronary artery disease were observed in ATSI patients. A non-significant trend towards higher 30-day mortality was observed in the Indigenous population (5.6% vs. 3.1%; p=0.244). CONCLUSIONS Cardiac surgery is generally required at a younger age in the Indigenous population with patients often presenting with more advanced disease. Despite often more advanced disease, surgical outcomes do not differ significantly from non-Indigenous patients. Continued focus on preventative strategies for coronary artery disease and RHD in the Indigenous population is required.
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Affiliation(s)
- Paul Wiemers
- Department of Cardiothoracic Surgery, The Townsville Hospital, Queensland, Australia; University of Queensland School of Medicine, Brisbane, Australia.
| | - Lucy Marney
- Department of Cardiothoracic Surgery, The Townsville Hospital, Queensland, Australia
| | - Reinhold Muller
- School of Public Health, Tropical Medicine and Rehabilitation Sciences, James Cook University, Townsville, Queensland, Australia
| | - Matthew Brandon
- Department of Cardiothoracic Surgery, The Townsville Hospital, Queensland, Australia
| | - Praveen Kuchu
- Department of Cardiothoracic Surgery, The Townsville Hospital, Queensland, Australia
| | - Kasandra Kuhlar
- Department of Cardiothoracic Surgery, The Townsville Hospital, Queensland, Australia
| | - Chimezie Uchime
- Department of Cardiothoracic Surgery, The Townsville Hospital, Queensland, Australia
| | - Dong Kang
- Department of Cardiothoracic Surgery, The Townsville Hospital, Queensland, Australia
| | - Nicole White
- Mathematical Sciences School, Queensland University of Technology, Brisbane, Australia
| | - Rachel Greenup
- Intensive Care Unit, Princess Alexandra Hospital, Brisbane, Australia
| | - John F Fraser
- University of Queensland School of Medicine, Brisbane, Australia; Critical Care Research Group, The Prince Charles Hospital, Brisbane, Australia
| | - Sumit Yadav
- Department of Cardiothoracic Surgery, The Townsville Hospital, Queensland, Australia
| | - Robert Tam
- Department of Cardiothoracic Surgery, The Townsville Hospital, Queensland, Australia
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27
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Abstract
A 40-year-old man with Crohn's disease was found to have recurrence of a large left ventricular mass on echocardiography during workup for stricturoplasty. He presented with left limb emboli. He had been diagnosed with a left ventricular thrombus 2 years earlier, with multiple cerebral and peripheral emboli, and underwent surgery. We carried out redo surgery, and histology revealed organized thrombus. We discuss the management of this complex case.
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Affiliation(s)
- Anand Iyer
- Department of Cardiothoracic Surgery, Townsville Hospital, Queensland, Australia
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28
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Cheng C, Tam R, Marney L, Miller L. Clinical Profile of the Systemic Inflammatory Response Syndrome After Cardiac Surgery at the Townsville Hospital, Australia. Heart Lung Circ 2011. [DOI: 10.1016/j.hlc.2011.08.045] [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: 10/15/2022]
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29
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Wiemers P, Muller R, Brandon M, Kuchu P, Kuhlar K, Marney L, Uchime C, Kang D, Yadav S, Tam R. Cardiac Surgery in Indigenous Australians—How Wide is ‘The Gap’? Heart Lung Circ 2011. [DOI: 10.1016/j.hlc.2010.11.010] [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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30
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Sharma R, Xabregas A, Tam R. Extensive Coronary Artery Reconstruction (ECAR) – A New Paradigm for Diffuse Coronary Artery Disease – Early Analysis. Heart Lung Circ 2011. [DOI: 10.1016/j.hlc.2010.10.059] [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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31
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Fiene A, McNeil K, Kermeen F, Chambers D, Stuart K, Fawcett J, Tam R, Hart G, Hopkins P. 35: The Australian Experience with Combined Heart-Lung-Liver Transplantation. J Heart Lung Transplant 2010. [DOI: 10.1016/j.healun.2009.11.042] [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: 10/19/2022] Open
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32
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Yadav S, Shehatha J, Konstantinov IE, Munck L, Tam R, McNeil K, Dunning J. OUTCOMES OF EN BLOC HEART-LUNG TRANSPLANTION: A REPORT OF 15 CASES. Heart Lung Circ 2007. [DOI: 10.1016/j.hlc.2007.02.065] [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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33
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Tam R, Joshi P, Konstantinov IE. A simple method of preparing artificial chordae for mitral valve repair. J Thorac Cardiovasc Surg 2006; 132:1486-7. [PMID: 17140991 DOI: 10.1016/j.jtcvs.2006.07.029] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/04/2006] [Accepted: 07/12/2006] [Indexed: 11/21/2022]
Affiliation(s)
- Robert Tam
- Prince Charles Hospital, Brisbane, Queensland, Australia
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34
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35
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El Abdellaoui H, Varaprasad CVNS, Barawkar D, Chakravarty S, Maderna A, Tam R, Chen H, Allan M, Wu JZ, Appleby T, Yan S, Zhang W, Lang S, Yao N, Hamatake R, Hong Z. Identification of isothiazole-4-carboxamidines derivatives as a novel class of allosteric MEK1 inhibitors. Bioorg Med Chem Lett 2006; 16:5561-6. [PMID: 16934458 DOI: 10.1016/j.bmcl.2006.08.048] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.3] [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: 06/02/2006] [Revised: 08/04/2006] [Accepted: 08/07/2006] [Indexed: 11/25/2022]
Abstract
The development of potent, orally bioavailable, and selective series of 5-amino-3-hydroxy-N(1-hydroxypropane-2-yl)isothiazole-4-carboxamidine inhibitors of MEK1 and MEK-2 kinase is described. Optimization of the carboxamidine and the phenoxyaniline group led to the identification of 55 which gave good potency as in vitro MEK1 inhibitors, and good oral exposure in rat.
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Affiliation(s)
- Hassan El Abdellaoui
- Drug Discovery, Valeant Pharmaceutical Research and Development, 3300 Hyland Avenue, Costa Mesa, CA 92626, USA.
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36
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Varaprasad CVNS, Barawkar D, El Abdellaoui H, Chakravarty S, Allan M, Chen H, Zhang W, Wu JZ, Tam R, Hamatake R, Lang S, Hong Z. Discovery of 3-hydroxy-4-carboxyalkylamidino-5-arylamino-isothiazoles as potent MEK1 inhibitors. Bioorg Med Chem Lett 2006; 16:3975-80. [PMID: 16725322 DOI: 10.1016/j.bmcl.2006.05.019] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2006] [Revised: 05/04/2006] [Accepted: 05/04/2006] [Indexed: 11/25/2022]
Abstract
3-Hydroxy-4-carboxyalkylamidino-5-arylamino-isothiazoles were discovered as potent in vitro MEK1 inhibitors.
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Affiliation(s)
- Chamakura V N S Varaprasad
- Drug Discovery, Valeant Pharmaceutical Research and Development, 3300 Hyland Avenue, Costa Mesa, CA 92626, USA.
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38
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Saxena P, Konstantinov IE, Burstow D, Tam R. Surgical repair of a large coronary artery aneurysm with arteriovenous fistula. J Thorac Cardiovasc Surg 2006; 131:1167-8. [PMID: 16678606 DOI: 10.1016/j.jtcvs.2005.11.039] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/04/2005] [Accepted: 11/16/2005] [Indexed: 11/18/2022]
Affiliation(s)
- Pankaj Saxena
- Department of Cardiac Surgery, The Prince Charles Hospital, Brisbane, QLD, Australia.
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Saxena P, Tam R. Late manifestation of a large congenital tracheoesophageal fistula in an adult. Tex Heart Inst J 2006; 33:60-2. [PMID: 16572873 PMCID: PMC1413598] [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] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
Congenital tracheoesophageal fistula in an adult is a rare condition. We describe the clinical presentation in a young woman after video-assisted thoracoscopic pleurodesis for spontaneous pneumothorax. She was found to have a very wide and short fistula in her neck. The tracheoesophageal defect was closed by a trap-door flap, using the posterior wall of the trachea. The patient made an uncomplicated recovery.
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Affiliation(s)
- Pankaj Saxena
- Department of Cardiothoracic Surgery, The Prince Charles Hospital, Brisbane, QLD, 4032 Australia.
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40
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Abstract
BACKGROUND Alveolar air leaks and broncho-pleural fistulae after thoracic surgical procedures contribute significantly to hospital morbidity and mortality. BioGlue has offered the thoracic surgeon an alternative to the products presently used to reduce the incidence of these complications. This retrospective study reviews our experience with this new adhesive. METHODS Forty patients upon whom BioGlue was used were identified through operation records. Pre-, intra- and postoperative data were collected to establish use, indications and outcome. RESULTS The predominant underlying pathology was malignancy. In 32 patients BioGlue was used during the primary procedure while in the remaining eight, persistent air- or lymph-leak led to a further procedure requiring the use of glue. The indications for BioGlue use were alveolar air leak (36), broncho-pleural fistula (2) and lymph leak (2). There was one death. In 35 out of 36 patients with alveolar air leak, BioGlue controlled the leak at the site of application. CONCLUSIONS Our results in this particular patient group indicate that BioGlue is a reliable adjunct in the reduction of alveolar air leaks. Although further studies are necessary to establish the role of BioGlue in thoracic surgery in comparison to other sealants, these initial results are promising.
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Affiliation(s)
- Jurgen Passage
- Department of Cardiac Surgery and Research, The Prince Charles Hospital, Brisbane, Australia.
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41
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Abstract
Use of internal thoracic arteries in coronary artery bypass surgery has become universal. Skeletonized internal thoracic artery is useful in coronary artery surgery for sequential anastomosis as it also provides a long length of graft. Skeletonizing the conduit is technically more difficult than harvesting it as a pedicle graft. We describe a technique of harvesting the internal thoracic artery in which 10 to 20 mL of normal saline is injected into the fascial plane of the left side of chest wall along the course of artery to develop a plane of dissection.
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Affiliation(s)
- Pankaj Saxena
- Department of Cardiac Surgery, The Prince Charles Hospital, Chermside, Brisbane, Queensland, Australia.
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42
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Saxena P, Tam R. Organized thrombus of tricuspid valve. Tex Heart Inst J 2005; 32:621; author reply 621-2. [PMID: 16429924 PMCID: PMC1351854] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
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43
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Affiliation(s)
- Przemysław Palka
- Department of Cardiology, the Prince Charles Hospital, Brisbane, Australia.
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44
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Coyle D, Palmer AJ, Tam R. Economic evaluation of pioglitazone hydrochloride in the management of type 2 diabetes mellitus in Canada. Pharmacoeconomics 2002; 20 Suppl 1:31-42. [PMID: 12036382 DOI: 10.2165/00019053-200220001-00004] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
INTRODUCTION Recently published clinical trial results have demonstrated that, in patients with type 2 diabetes mellitus, treatment with pioglitazone hydrochloride as a first-line therapy can lead to significant improvements in glycosylated haemoglobin, total cholesterol, high density lipoprotein cholesterol and triglycerides. Given the results of these trials, we assessed the cost effectiveness of the use of pioglitazone as a first-line therapy in Canada. METHODS A Markov model was used to determine the health outcomes and economic impact for patients with type 2 diabetes, from the perspective of a provincial ministry of health. The model incorporated six complications of diabetes: hypoglycaemia, acute myocardial infarction, stroke, lower extremity amputation, nephropathy, and retinopathy. Transition probabilities and costs were taken from published literature. Analysis compared treatment strategies with different first-line therapies: pioglitazone, glibenclamide (glyburide), metformin, and diet and exercise. RESULTS Compared with other strategies, a pioglitazone-based strategy was estimated to reduce the cumulative incidence of severe clinical events and long-term complications by between 23 and 36% and to increase discounted life expectancy by between 0.13 and 0.35 life-years. The discounted incremental cost per life-year gained of a first-line pioglitazone-based strategy was 54,000 Canadian dollars ($Can) compared with metformin, $Can42,000 compared with glibenclamide and $Can27,000 compared with diet and exercise. CONCLUSIONS When compared with other currently funded chronic therapy, these results demonstrate that a treatment strategy employing pioglitazone as a first-line therapy may be cost effective for certain patient strata.
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Affiliation(s)
- Douglas Coyle
- Departments of Medicine and Epidemiology, and Community Medicine, University of Ottawa; Clinical Epidemiology, Ottawa Health Research Institute, Ottawa Hospital; Ottawa, Ontario, Canada.
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45
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Chen KP, Herman PR, Zhang J, Tam R. Fabrication of strong long-period gratings in hydrogen-free fibers with 157-nm F2-laser radiation. Opt Lett 2001; 26:771-773. [PMID: 18040445 DOI: 10.1364/ol.26.000771] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
Long-period gratings were fabricated in standard telecommunication fiber (Corning SMF-28) by use of what is believed to be record short-wavelength light from a 157-nm F(2) laser. Strong loss peaks were formed without the need for enhancement techniques such as hydrogen loading. The magnitude of the attenuation peak was sensitive to the single-pulse laser fluence, decreasing with increasing pulse fluence as a result of nonuniform 157-nm laser interaction with both the fiber cladding and core. The long-period fiber gratings have good wavelength stability (Dlambda~7 nm) under thermal annealing at 150 degrees C.
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46
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Tam R. A modification to aid open tracheostomy. J R Coll Surg Edinb 2001; 46:189; author reply 190. [PMID: 11478025] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/20/2023]
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47
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Tam R. Percutaneous (Portex) tracheostomy: an audit of the Newcastle experience. Ann R Coll Surg Engl 2001; 83:144. [PMID: 11320927 PMCID: PMC2503342] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/19/2023] Open
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48
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Gardner M, Tam R. Off pump cabg (OPCAB) in patients with ascending aortic pathology. Heart Lung Circ 2000. [DOI: 10.1046/j.1443-9506.2000.09569.x] [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: 11/20/2022]
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49
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Lau Q, Thomson B, Burstow D, Tesar P, Tam R. Is an annuloplasty ring necessary in mitral valve repair for isolated posterior leaflet prolapse? Heart Lung Circ 2000. [DOI: 10.1046/j.1443-9506.2000.0948x.x] [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: 11/20/2022]
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50
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Lau Q, Burstow D, Tam R. Is an annuloplasty ring necessary in mitral valve repair for isolated posterior leaflet prolapse? Heart Lung Circ 2000. [DOI: 10.1046/j.1443-9506.2000.09144.x] [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: 11/20/2022]
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