1
|
Billah M, Ridiandries A, Allahwala UK, Mudaliar H, Dona A, Hunyor S, Khachigian LM, Bhindi R. Remote Ischemic Preconditioning induces Cardioprotective Autophagy and Signals through the IL-6-Dependent JAK-STAT Pathway. Int J Mol Sci 2020; 21:ijms21051692. [PMID: 32121587 PMCID: PMC7084188 DOI: 10.3390/ijms21051692] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [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: 01/12/2020] [Revised: 02/19/2020] [Accepted: 02/27/2020] [Indexed: 02/08/2023] Open
Abstract
Autophagy is a cellular process by which mammalian cells degrade and assist in recycling damaged organelles and proteins. This study aimed to ascertain the role of autophagy in remote ischemic preconditioning (RIPC)-induced cardioprotection. Sprague Dawley rats were subjected to RIPC at the hindlimb followed by a 30-min transient blockade of the left coronary artery to simulate ischemia reperfusion (I/R) injury. Hindlimb muscle and the heart were excised 24 h post reperfusion. RIPC prior to I/R upregulated autophagy in the rat heart at 24 h post reperfusion. In vitro, autophagy inhibition or stimulation prior to RIPC, respectively, either ameliorated or stimulated the cardioprotective effect, measured as improved cell viability to mimic the preconditioning effect. Recombinant interleukin-6 (IL-6) treatment prior to I/R increased in vitro autophagy in a dose-dependent manner, activating the Janus kinase/signal transducers and activators of transcription (JAK-STAT) pathway without affecting the other kinase pathways, such as p38 mitogen-activated protein kinases (MAPK), and glycogen synthase kinase 3 Beta (GSK-3β) pathways. Prior to I/R, in vitro inhibition of the JAK-STAT pathway reduced autophagy upregulation despite recombinant IL-6 pre-treatment. Autophagy is an essential component of RIPC-induced cardioprotection that may upregulate autophagy through an IL-6/JAK-STAT-dependent mechanism, thus identifying a potentially new therapeutic option for the treatment of ischemic heart disease.
Collapse
Affiliation(s)
- Muntasir Billah
- Department of Cardiology, Kolling Institute of Medical Research, Northern Sydney Local Health District, St Leonards, NSW 2065, Australia; (A.R.); (U.K.A.); (H.M.); (A.D.); (S.H.); (R.B.)
- Sydney Medical School Northern, University of Sydney, Sydney, NSW 2006, Australia
- School of Life Sciences, Independent University Bangladesh, Dhaka 1229, Bangladesh
- Correspondence:
| | - Anisyah Ridiandries
- Department of Cardiology, Kolling Institute of Medical Research, Northern Sydney Local Health District, St Leonards, NSW 2065, Australia; (A.R.); (U.K.A.); (H.M.); (A.D.); (S.H.); (R.B.)
- Sydney Medical School Northern, University of Sydney, Sydney, NSW 2006, Australia
| | - Usaid K Allahwala
- Department of Cardiology, Kolling Institute of Medical Research, Northern Sydney Local Health District, St Leonards, NSW 2065, Australia; (A.R.); (U.K.A.); (H.M.); (A.D.); (S.H.); (R.B.)
- Sydney Medical School Northern, University of Sydney, Sydney, NSW 2006, Australia
| | - Harshini Mudaliar
- Department of Cardiology, Kolling Institute of Medical Research, Northern Sydney Local Health District, St Leonards, NSW 2065, Australia; (A.R.); (U.K.A.); (H.M.); (A.D.); (S.H.); (R.B.)
| | - Anthony Dona
- Department of Cardiology, Kolling Institute of Medical Research, Northern Sydney Local Health District, St Leonards, NSW 2065, Australia; (A.R.); (U.K.A.); (H.M.); (A.D.); (S.H.); (R.B.)
| | - Stephen Hunyor
- Department of Cardiology, Kolling Institute of Medical Research, Northern Sydney Local Health District, St Leonards, NSW 2065, Australia; (A.R.); (U.K.A.); (H.M.); (A.D.); (S.H.); (R.B.)
| | - Levon M. Khachigian
- Vascular Biology and Translational Research, School of Medical Sciences, University of New South Wales, Sydney, NSW 2052, Australia;
| | - Ravinay Bhindi
- Department of Cardiology, Kolling Institute of Medical Research, Northern Sydney Local Health District, St Leonards, NSW 2065, Australia; (A.R.); (U.K.A.); (H.M.); (A.D.); (S.H.); (R.B.)
- Sydney Medical School Northern, University of Sydney, Sydney, NSW 2006, Australia
| |
Collapse
|
2
|
Billah M, Mudaliar H, Hunyor S, Bhindi R. Early growth response-1 functions as a master regulator of remote hypoxic preconditioning. Heart Lung Circ 2015. [DOI: 10.1016/j.hlc.2015.06.671] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
|
3
|
Bailey EA, Bailey DL, Hunyor S, Ladd L, Bautovich GJ. Translation of Methodology Used In Human Myocardial Imaging to a Sheep Model of Acute Myocardial Infarction. Asia Ocean J Nucl Med Biol 2013; 1:10-21. [PMID: 27408845 PMCID: PMC4927046] [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] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/01/2022]
Abstract
INTRODUCTION Pre-clinical investigation of stem cells for repairing damaged myocardium predominantly uses rodents, however large animals have cardiac circulation closely resembling the human heart. The aim of this study was to evaluate whether SPECT/CT myocardial perfusion imaging (MPI) could be used for assessing sheep myocardium following an acute myocardial infarction (MI) and response to intervention. METHODS Eighteen sheep were enrolled in a pilot study to evaluate [(99m)Tc]-sestamibi MPI at baseline, post-MI and after therapy. Modifications to the standard MPI protocols were developed. All data was reconstructed with OSEM using CT-derived attenuation and scatter correction. Standard analyses were performed and inter-observer agreement was measured using Kappa (κ). Power determined the sample sizes needed to show statistically significant changes due to intervention. RESULTS Ten sheep completed the full protocol. Data processed was performed with pre-existing hardware and software used in human MPI scanning. No improvement in perfusion was seen in the control group, however improvements of 15%-35% were seen after intra-myocardial stem cell administration. Inter-observer agreement was excellent (К=0.89). Using a target power of 0.9, 28 sheep were required to detect a 10-12% change in perfusion. CONCLUSION This study demonstrates the suitability of large animal models for imaging with standard MPI protocols and its feasibility with a manageable number of animals. These protocols could be translated into humans to study the efficacy of stem cell therapy in heart regeneration and repair.
Collapse
Affiliation(s)
- Elizabeth A Bailey
- Department of Nuclear Medicine, Royal North Shore Hospital, Australia,Discipline of Medical Radiation Sciences, University of Sydney, Australia,*Corresponding author: Elizabeth Bailey, Department of Nuclear Medicine, Royal North Shore Hospital, St Leonards, NSW. Australia 2065; Fax: +61 (0)2 9926 4099; Phone: +61 (0)2 9926 4440;
| | - Dale L Bailey
- Department of Nuclear Medicine, Royal North Shore Hospital, Australia,Discipline of Medical Radiation Sciences, University of Sydney, Australia,Sydney Medical School, University of Sydney, Australia
| | - Stephen Hunyor
- Department of Cardiology, Royal North Shore Hospital, Australia,Sydney Medical School, University of Sydney, Australia,Cardiac Technology Centre, North Shore Heart Research Group, Kolling Institute, Australia
| | - Leigh Ladd
- Cardiac Technology Centre, North Shore Heart Research Group, Kolling Institute, Australia,Charles Sturt University, Wagga Wagga, Australia
| | | |
Collapse
|
4
|
|
5
|
Rayner B, Figtree G, Lay W, Sabaretnam T, Mazar J, Weaver J, Grieve S, Hunyor S, Khachigian L, Bhindi R. The Intracoronary Delivery of DNAzymes Targeting Egr-1 Upon Restoration of Blood Flow Reduces Inflammation and Subsequent Tissue Damage Following Acute Myocardial Ischemia Reperfusion. Heart Lung Circ 2012. [DOI: 10.1016/j.hlc.2012.05.446] [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]
|
6
|
Mau J, Menzie S, Huang Y, Ward M, Hunyor S. Nonsurround, nonuniform, biventricular-capable direct cardiac compression provides Frank-Starling recruitment independent of left ventricular septal damage. J Thorac Cardiovasc Surg 2011; 142:209-15. [DOI: 10.1016/j.jtcvs.2010.05.057] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/28/2009] [Revised: 04/14/2010] [Accepted: 05/06/2010] [Indexed: 12/31/2022]
|
7
|
Bassin L, Yong A, Kilpatrick D, Hunyor S. Deep Hypothermia in Sheep Produces Right Ventricular ST Elevation. Heart Lung Circ 2011. [DOI: 10.1016/j.hlc.2011.05.199] [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]
|
8
|
Huang Y, Timworth K, Hunyor S, Williams B, Brady P. Immediate Effect of Acute Device Attachment to Heart on Cardiac Function in Sheep—Haemodynamics. Heart Lung Circ 2010. [DOI: 10.1016/j.hlc.2010.04.105] [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: 10/19/2022]
|
9
|
Bassin L, Yong A, Kilpatrick D, Hunyor S. The Origin of the J Wave in Hypothermia. Heart Lung Circ 2010. [DOI: 10.1016/j.hlc.2010.06.887] [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]
|
10
|
Mau J, Menzie S, Huang Y, Hunyor S. Implanted, Non-blood Contacting Direct Cardiac Compression Device (DCCD) Confers Passive Systolic LV Offloading. Heart Lung Circ 2009. [DOI: 10.1016/j.hlc.2009.05.170] [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]
|
11
|
Seow J, Jackson C, Hunyor S. Regulation of Wnt ligands in murine resident-cardiac stem cells (CSC) and cardiogenesis. Heart Lung Circ 2009. [DOI: 10.1016/j.hlc.2009.05.611] [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]
|
12
|
Tomka J, Turner A, Doyle A, Lay W, Mughal N, Hunyor S. Predictable Myocardial Infarct Model in Sheep: Definition of Coronary Anatomy Using Corrosion Casting. Heart Lung Circ 2009. [DOI: 10.1016/j.hlc.2009.05.461] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
|
13
|
Mau J, Menzie S, Ward M, Bundgaard H, Hunyor S. Time-dependent response of both ventricles after septal ablation: Implications for biventricular support after left ventricular assist device placement. J Thorac Cardiovasc Surg 2007; 134:579-86. [PMID: 17723802 DOI: 10.1016/j.jtcvs.2007.03.048] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/20/2006] [Revised: 02/23/2007] [Accepted: 03/26/2007] [Indexed: 10/22/2022]
Abstract
OBJECTIVES An ovine model of septal ablation was studied to elucidate the mechanisms involved in right ventricular failure when commencing left ventricular mechanical assistance. The disruption of ventricular interdependence after acute and chronic septal injury was examined. METHODS Twelve sheep underwent percutaneous transluminal septal myocardial ablation using 0.6 mL ethanol. Twelve other sheep underwent a sham procedure. Left ventricular and right ventricular pressure and volume (conductance) response 15 minutes and 4 weeks postinjury were measured. Ultrasonic crystals measured chamber dimensions and wall movement. Areas at risk and infarct zones were quantified. RESULTS Compared with sham, ablation chronically reduced systolic interventricular septal thickening (18.4% +/- 5.8% vs 7.3% +/- 3.1%; P < .001) and acutely increased right ventricular ejection fraction (37.6% +/- 8.5% vs 69.9% +/- 7.2%; P < .001), preload recruitable stroke work (42.0 +/- 4.4 erg x 10(3) vs 48.7 +/- 2.0 erg x 10(3), P < .001), end-systolic elastance (1.03 +/- 0.19 mm Hg mL(-1) vs 1.31 +/- 0.18 mm Hg mL(-1); P < .001), and Tau (24.9 +/- 3.8 ms vs 29.6 +/- 8.2 ms; P < .001). In contrast, for left ventricular ejection fraction (55.5% +/- 5.9% vs 38.9% +/- 7.7%; P < .001), preload recruitable stroke work (85.9 +/- 10.6 mm Hg vs 66.5 +/- 9.6 mm Hg; P < .001) and elastance (2.13 +/- 0.51 mm Hg mL(-1) vs 1.81 +/- 0.44 mm Hg mL(-1); P < .001) were reduced, but Tau increased (22.0 +/- 3.5 ms vs 28.9 +/- 5.8 ms; P < .001) and remained elevated at 4 weeks compared with sham. The area at risk was the same between groups, and injury was limited to the septum (17.2% +/- 2.7% vs 2.9% +/- 5.8%; P < .001). CONCLUSIONS Acute and chronic hemodynamic responses are distinctly different after septal injury; the acute response demonstrates a paradoxical motion. Resolution of this motion at 4 weeks is suggestive of reduced septal compliance and buttressing. Ventricular interactions after placement of a left ventricular assist device will vary depending on the injury duration.
Collapse
Affiliation(s)
- James Mau
- Cardiac Technology Centre, Kolling Institute, Australia.
| | | | | | | | | |
Collapse
|
14
|
Mau J, Menzie S, Huang Y, Hunyor S. Direct Cardiac Compression Device (DCCD) Demonstrates Frank–Starling Enhancement and Preload Recruitment Capability. Heart Lung Circ 2007. [DOI: 10.1016/j.hlc.2007.06.449] [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: 10/23/2022]
|
15
|
Abstract
AIMS We examined cardiomyocyte apoptosis in chronic heart failure (HF) and its possible link to elevated wall stress. METHODS AND RESULTS Moderate HF was produced in sheep by sequential coronary microembolization. Six months later, the animals remained in a stable compensated haemodynamic state of HF. Apoptosis of cardiomyocytes in left ventricles was verified using Western blotting based on increased expression of: the apoptosis-associated death receptor Fas (1.5-fold); its ligand (FasL, 2.0-fold); and an upstream protease caspase-8 (2.7-fold) as well as its active cleavage peptide, p20 (5.6-fold). Previously we have reported the elevated expression of caspase-3 in the same animal model. The occurrence of apoptotic cardiomyocytes (0.3%) was quantified by TUNEL assays. Haemodynamic analysis indicated that ventricular dilatation, without wall thickening, caused a 2-fold increase in LV wall stress which, together with LV end-diastolic pressure, was linearly correlated with expression of Fas/FasL. Immunohistochemical studies localized FasL and caspase-8 to intercalated discs, suggesting that wall stress may play a role in initiating cardiomyocyte apoptosis. CONCLUSION Apoptosis of cardiomyocytes in chronic HF is associated with increased wall stress, which may be responsible for the activation of a Fas/FasL and caspase-8 interaction in the region of intercalated discs.
Collapse
Affiliation(s)
- L Jiang
- Department of Cardiology, Cardiac Technology Centre, Royal North Shore Hospital, St. Leonards, NSW, Australia.
| | | | | | | |
Collapse
|
16
|
Huang Y, Shirota K, Yuasa T, Ramanathan T, Hunyor S. Differing mechanisms for dobutamine in enhancement of cardiac work efficiency in normal and failing hearts. Heart Lung Circ 2003. [DOI: 10.1046/j.1443-9506.2003.03039.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]
|
17
|
Ramanathan T, Shirota K, Morita S, Nishimura T, Huang Y, Hunyor S. Oxygen utilisation efficiency is impaired in the diabetic heart and reversed by substrate enhancement. Heart Lung Circ 2003. [DOI: 10.1046/j.1443-9506.2003.01326.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]
|
18
|
Gallagher G, Huang Y, Plekhanov S, Morita S, Ramanathan T, Brady P, Hunyor S. Effects of the ‘heart patch’ direct cardiac compression (DCC) device on coronary flow (CBF) patterns in acute heart failure sheep. Heart Lung Circ 2003. [DOI: 10.1046/j.1443-9506.2003.0223x.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]
|
19
|
Ramanathan T, Shirota K, Morita S, Nishimura T, Huang Y, Zheng X, Hunyor S. Left ventricular oxygen utilization efficiency is impaired in chronic streptozotocin-diabetic sheep. Cardiovasc Res 2002; 55:749-56. [PMID: 12176124 DOI: 10.1016/s0008-6363(02)00497-2] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
OBJECTIVE Energy metabolism is altered in the diabetic heart. However, direct in vivo evidence that diabetes impairs energetics at the chamber level is lacking. Therefore, we investigated the effect of diabetes on left ventricular (LV) energetics in a chronic ovine model. METHODS Diabetes was induced in Merino-cross sheep with streptozotocin. Experiments were performed in five animals following 12 months untreated diabetes and six animals served as controls. Open-chest anesthetized sheep were instrumented to determine the LV pressure-volume relationship, oxygen consumption and free fatty acid uptake. RESULTS Diabetes impaired LV contractility (1.5+/-0.5 vs. 2.3+/-0.5 mmHg/ml, P<0.01). Stroke work was preserved but stroke work efficiency (stroke work/pressure-volume area) deteriorated (52+/-4 vs. 58+/-3%, P<0.01). Plasma free fatty acid levels increased (1885+/-1078 vs. 354+/-203 mmol/l, P<0.01) as did LV free fatty acid uptake (312+/-278 vs. 90+/-47 micromol/beat per 100 g LV, P=0.04). Contractile efficiency decreased (31.9+/-1.4 vs. 50.0+/-8.7%, P<0.01) while unloaded oxygen consumption did not change significantly. Therefore, LV oxygen utilization efficiency (stroke work/LV oxygen consumption) was compromised in the diabetic heart (14.9+/-2.8 vs. 24.3+/-4.0%, P<0.001). CONCLUSION This is the first study to demonstrate that diabetes alters ventricular energetics in vivo. LV oxygen utilization efficiency is impaired as a consequence of decreased contractile efficiency and stroke work efficiency. Impaired efficiency of oxygen utilization may explain in part the increased sensitivity of the diabetic heart to ischemia and the accelerated deterioration of ventricular function in diabetic patients.
Collapse
Affiliation(s)
- Tharumenthiran Ramanathan
- Cardiac Technology Centre, Department of Cardiology, Block 4, Level 3, Royal North Shore Hospital, St Leonards, Sydney, NSW 2065, Australia.
| | | | | | | | | | | | | |
Collapse
|
20
|
Carter N, Henderson R, Lal S, Hart M, Booth S, Hunyor S. Cardiovascular and autonomic response to environmental noise during sleep in night shift workers. Sleep 2002; 25:457-64. [PMID: 12071548] [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] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/25/2023] Open
Abstract
Polysomnograph, beat-by-beat heart rate and blood pressure were monitored in night shift workers exposed to environmental and laboratory noise events during day sleep. The study was carried out in a sleep laboratory. Subjects were nine young, healthy female night shift workers. Recorded noises from trucks, civilian aircraft, low altitude military aircraft and tones were presented at 55, 65, and 75 L(Amax). Sleep stage, heart rate, and systolic and diastolic blood pressures before and immediately after onset of noise events were compared. Spectral analyses of heart rate and blood pressure variabilities were used to compare sympathetic and parasympathetic nervous tone in 10-min. intervals containing noise and quiet. Heart rate was responsive to noise level but not noise type. Blood pressure increased primarily to sounds of sudden onset. Noise-induced awakening and alpha EEG responses were related to BP increase. Increase in HR was greatest when subjects were awakened by noise or already awake. Spectral analysis of BP variabilities indicated increased sympathetic vascular tone due to noise. Similar analyses of HR data indicated no noise effect. No habituation to noise was apparent over three consecutive sleep sessions. It was concluded that over the range of noise levels used, heart rate responds to noise level during sleep; blood pressure to sounds of sudden onset. Spectral analysis of blood pressure variabilities is a sensitive measure of autonomic nervous response to environmental noise and should also be studied in subjects sleeping at home.
Collapse
|
21
|
Carter N, Henderson R, Lal S, Hart M, Booth S, Hunyor S. Cardiovascular and Autonomic Response to Environmental Noise During Sleep in Night Shift Workers. Sleep 2002. [DOI: 10.1093/sleep/25.4.444] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
|
22
|
Craig AR, Bartrop R, Lal SKL, Henderson RJ, Hart M, Hunyor S. Optimizing blood pressure reduction: predicting success in the home environment. Clin Psychol Psychother 2001. [DOI: 10.1002/cpp.248] [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: 11/06/2022]
|
23
|
Souresrafil O, Hunyor S. Haemodynamic benefits of bi-ventricular pacing using an automated echocardiographic border detection, in the sheep heart failure model. Europace 2001. [DOI: 10.1016/eupace/2.supplement_1.a92] [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: 10/14/2022] Open
|
24
|
Souresrafil O, Hunyor S, Xing J. Effects of biventricular pacing on defibrillaiton thresholds in the sheep heart failure model. Europace 2001. [DOI: 10.1016/eupace/2.supplement_1.a91-b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
|
25
|
Abstract
We examined the DNase activity as well as the expression of the caspases in left ventricles of failing sheep hearts and compared it with samples from normal controls. The sheep model of chronic ischemic heart failure was developed by intracoronary microembolisation. Moderate heart failure was defined as a decrease of left ventricular (LV) ejection fraction (EF) to 35% or less and was stable for four weeks after the last embolisation. The failing hearts were harvested from these animals six months later. Bovine pancreas DNase I was used as a standard for the DNase zymograms. In normal sheep left ventricles, a low level of the DNase I-like activity was detected (1.16 +/- 0.17 pg/100 microg protein, n = 20), whereas it was elevated (3.64 +/- 0.49 pg/100 microg, n = 32, p < 0.001) in the ischemic failing LV samples. The identity of the DNase in sheep is yet to be fully characterised. However, we also detected the expression of caspase-2 and caspase-3 by Western blotting. There was a 2.2-fold increased expression of caspase-2 p < 0.001 = and a 2.6-fold increased expression of caspase-3 p < 0.001) in failing left ventricles compared to normal samples.
Collapse
Affiliation(s)
- L Jiang
- Cooperative Research Centre for Cardiac Technology, Royal North Shore Hospital, St. Leonards, NSW, Australia.
| | | | | | | | | |
Collapse
|
26
|
Abstract
1. External compression of the human brachial artery results in waveform reflection. 2. Resonant waves are found superimposed on the original blood pressure signal. 3. The mechanism may be likened to the operation of an organ pipe with reflections at both ends of an arterial segment. 4. This has implications for measurements in arteries where external pressure is applied.
Collapse
Affiliation(s)
- H Kobler
- Department of Cardiology, Royal North Shore Hospital, St Leonards, New South Wales, Australia
| | | | | | | | | |
Collapse
|
27
|
Abstract
Five-hundred and thirty-two patients with ischaemic-like chest pain referred for symptom-limited exercise thallium myocardial perfusion studies, were assessed on a range of psychosocial measures. Three groups of patients were identified on the basis of their perfusion studies: (1) normal thallium perfusion; (2) current myocardial ischaemia; and (3) past myocardial infarction (but no current ischaemia). There were no significant psychological differences between these groups on a wide range of measures which included depression, state and trait anxiety, Type A behaviour, personality, suppression of affect, locus of control, alexythymia, and hypochondriasis. Significant differences were identified, however, on measures of anger and coping style. Subjects with no current ischaemia (normal thallium perfusion and those with past myocardial infarction) had higher scores on 'immature coping' and 'anger in', than subjects with current myocardial ischaemia. These findings are discussed in the light of other published research.
Collapse
Affiliation(s)
- C Tennant
- Department of Academic Psychiatry, Royal North Shore Hospital, Sydney, Australia
| | | | | | | | | | | | | | | | | |
Collapse
|
28
|
Scott A, Mihailidou A, Smith R, Kellow J, Jones M, Lorang C, Hunyor S, Lorang M, Hoschl R, Tennant C. Functional gastrointestinal disorders in unselected patients with non-cardiac chest pain. Scand J Gastroenterol 1993; 28:585-90. [PMID: 8362209 DOI: 10.3109/00365529309096092] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Patients with non-cardiac chest pain (NCCP) (n = 387) and cardiac chest pain (CCP) (n = 93) were compared with community controls (n = 81), using a symptom questionnaire that assessed the presence of irritable bowel syndrome (IBS), functional dyspepsia, and oesophageal dysfunction and chest pain characteristics. A significantly (p < 0.05) increased prevalence of symptoms compatible with IBS occurred in NCCP patients when compared with those with CCP and with controls. Dysphagia was more frequent in both those with non-cardiac and cardiac chest pain than in controls; this was not apparent, however, when patients with concomitant IBS were excluded. The presence of oesophageal or gastrointestinal symptoms did not enable discrimination with regard to the chest pain characteristics. We conclude that unselected referred patients with documented NCCP are more likely to have IBS and that the presence of oesophageal symptoms such as dysphagia may merely reflect the spectrum of the 'irritable gut'.
Collapse
Affiliation(s)
- A Scott
- Dept. of Nuclear Medicine, Royal North Shore Hospital, Sydney, Australia
| | | | | | | | | | | | | | | | | | | |
Collapse
|
29
|
Hunyor S, Nyberg G. Comparison of intra-arterial and indirect blood pressures at rest and during isometric exercise in hypertensive patients before and after metoprolol. Br J Clin Pharmacol 1978; 6:109-14. [PMID: 678386 PMCID: PMC1429419 DOI: 10.1111/j.1365-2125.1978.tb00834.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
1. Blood pressure was measured both directly and indirectly in seven hypertensive patients before and after a single oral dose of 100 mg metoprolol, at rest and during sustained handgrip. 2. Intra-arterially measured systolic and diastolic blood pressure increased linearly with time during sustained handgrip at 50% of maximal voluntary contraction. This linearity persisted for 60 s or more in most cases. Heart rate increased linearly for the first 30 s. 3. Indirectly measured blood pressure using an observer bias minimizing Auto-Manometer, under-read systolic and over-read diastolic pressure both at rest and during handgrip. 4. By exact timing of recorded values during handgrip and linear extrapolation (or interpolation) from base-line readings, mean values at 30 and 60 s of handgrip were calculated. The relationship between direct and indirect values remained the same at base-line and 30 s of handgrip. At 60 s of handgrip, this was true only for diastolic pressure. For systolic pressure, indirect and direct values almost coincided. 5. After metoprolol, directly recorded pressure fell slightly (7--12 mm Hg, 0.02 less than P less than 0.10), both at rest and during handgrip, and heart rate fell by 15--18 beats/min (P less than 0.01). The systolic blood pressure and heart rate effect of metoprolol at 1 min handgrip correlated with peak plasma drug levels. Indirectly measured blood pressure did not change significantly. 6. The rate of rise in heart rate and blood pressure from base-line to 60 s handgrip was not significantly influenced by metoprolol.
Collapse
|