NHMRC Research Fellowship 2009 - MAY

Intrathecal Administration of Losartan Reduces Directly Recorded Cardiac Sympathetic Nerve Activity in Ovine Heart Failure

S Leversha, AM Allen, CN May, R Ramchandra

2019-10-01

Early and preferential activation of cardiac sympathetic nerve activity (CSNA) is one of the strongest prognostic markers of heart..

Neurohumoral interactions contributing to renal vasoconstriction and decreased renal blood flow in heart failure

R Ramchandra, DT Xing, M Matear, G Lambert, AM Allen, CN May

2019-09-01

In heart failure (HF), increases in renal sympathetic nerve activity (RSNA), renal norepinephrine spillover, and renin release cau..

Mechanisms underlying the increased cardiac norepinephrine spillover in heart failure

R Ramchandra, SG Hood, D Xing, GW Lambert, CN May

2018-08-01

Patients with heart failure (HF) have increased levels of cardiac norepinephrine (NE) spillover, which is an independent predictor..

Role of endothelin-1 in mediating changes in cardiac sympathetic nerve activity in heart failure

Y Abukar, CN May, R Ramchandra

2016-01-01

Heart failure (HF) is associated with increased sympathetic nerve activity to the heart (CSNA), which is directly linked to mortal..

Evidence that the MEK/ERK but not the PI3K/Akt pathway is required for protection from myocardial ischemia-reperfusion injury by 3′,4′-dihydroxyflavonol

CJ Thomas, NR Lim, A Kedikaetswe, YY Yeap, OL Woodman, DCH Ng, CN May

2015-07-05

The novel pro-drug of 3′4′-dihydroxyflavonol, NP202, potently reduces myocardial infarct size resulting from ischemia-reperfusion ..

Short-term effects of catheter-based renal denervation on cardiac sympathetic drive and cardiac baroreflex function in heart failure

LC Booth, MP Schlaich, EE Nishi, ST Yao, J Xu, R Ramchandra, GW Lambert, CN May

2015-07-01

Objectives: Sympathetic drive, especially to the heart, is elevated in heart failure and is strongly associated with poor outcome...

Variable responses of regional renal oxygenation and perfusion to vasoactive agents in awake sheep

P Calzavacca, RG Evans, M Bailey, R Bellomo, CN May

2015-01-01

Vasoactive agents are used in critical care to optimize circulatory function, but their effects on renal tissue oxygenation in the..

The low frequency power of heart rate variability is neither a measure of cardiac sympathetic tone nor of baroreflex sensitivity

D Martelli, A Silvani, RM McAllen, CN May, R Ramchandra

2014-10-01

The lack of noninvasive approaches to measure cardiac sympathetic nerve activity (CSNA) has driven the development of indirect est..

Tonic arterial chemoreceptor activity contributes to cardiac sympathetic activation in mild ovine heart failure

DT Xing, CN May, LC Booth, R Ramchandra

2014-08-01

New Findings: What is the central question of this study? What is the role of the peripheral chemoreflex in driving the increased ..

Intracarotid hypertonic sodium chloride differentially modulates sympathetic nerve activity to the heart and kidney

R Frithiof, T Xing, MJ McKinley, CN May, R Ramchandra

2014-04-15

Hypertonic NaCl infused into the carotid arteries increases mean arterial pressure (MAP) and changes sympathetic nerve activity (S..

Tonic arterial chemoreceptor activity contributes to cardiac, but not renal, sympathetic activation in heart failure (1169.2)

Daniel Xing, Clive May, Rohit Ramchandra

2014-04-01

<jats:p>In heart failure (HF) cardiac sympathetic nerve activity (CSNA) is increased, which has detrimental effects on the heart. ..

Central exogenous nitric oxide decreases cardiac sympathetic drive and improves baroreflex control of heart rate in ovine heart failure

R Ramchandra, SG Hood, CN May

2014-01-01

Heart failure (HF) is associated with increased cardiac and renal sympathetic drive, which are both independent predictors of poor..

Distribution of orexin-1 receptor-green fluorescent protein- (OX1-GFP) expressing neurons in the mouse brain stem and pons: Co-localization with tyrosine hydroxylase and neuronal nitric oxide synthase

A Darwinkel, D Stanić, LC Booth, CN May, AJ Lawrence, ST Yao

2014-01-01

We used a reporter mouse line in which green fluorescent protein (GFP) was inserted into the orexin-1 receptor (OX<inf>1</inf>) lo..

Effects of renal denervation on regional hemodynamics and kidney function in experimental hyperdynamic sepsis

P Calzavacca, M Bailey, E Velkoska, LM Burrell, R Ramchandra, R Bellomo, CN May

2014-01-01

OBJECTIVE: To determine the influence of the renal sympathetic nerves on the pathogenesis of septic acute kidney injury. DESIGN: I..

Renal histopathology during experimental septic acute kidney injury and recovery

C Langenberg, G Gobe, S Hood, CN May, R Bellomo

2014-01-01

OBJECTIVES:: Our understanding of septic acute kidney injury is limited. We therefore assessed renal histopathological changes ind..

Systemic and renal haemodynamic effects of fluid bolus therapy: Sodium chloride versus sodium octanoate-balanced solution

L Ke, P Calzavacca, M Bailey, CN May, WQ Li, J Bertolini, R Bellomo

2014-01-01

Background: Solutions with high chloride concentrations, like normal saline (NS), may adversely affect renal blood flow (RBF). We ..

Cardioprotective 3',4'-dihydroxyflavonol attenuation of JNK and p38 MAPK signalling involves CaMKII inhibition

NR Lim, CJ Thomas, LS Silva, YY Yeap, S Yap, JR Bell, LMD Delbridge, MA Bogoyevitch, OL Woodman, SJ Williams, CN May, DCH Ng

2013-12-01

DiOHF (3',4'-dihydroxyflavonol) is cardioprotective against I/R (ischaemia/reperfusion) injury. The biological activities of flavo..

Clonidine and dexmedetomidine increase the pressor response to norepinephrine in experimental sepsis: A pilot study*

A Geloen, K Chapelier, A Cividjian, E Dantony, M Rabilloud, CN May, L Quintin

2013-12-01

OBJECTIVE:: During septic shock, vasopressors are a cornerstone of therapy. In septic shock, very high doses of vasopressors somet..

Intra-carotid angiotensin II activates tyrosine hydroxylase-expressing rostral ventrolateral medulla neurons following blood-brain barrier disruption in rats

ST Yao, CN May

2013-08-05

Angiotensin II (Ang II) in the periphery and within the brain plays important roles in blood pressure control. Circulating angiote..

Organ selective regulation of sympathetic outflow by the brain angiotensin system

R Ramchandra, ST Yao, CN May

2013-08-01

Angiotensin II (Ang II) has actions on the sympathetic nervous system both as a circulating hormone acting on the circumventricula..

Cardiac sympathoexcitation in heart failure

CN May, ST Yao, LC Booth, R Ramchandra

2013-04-01

Heart failure (HF) is a serious debilitating condition with poor survival rates and an increasing level of prevalence. The excessi..

The role of the paraventricular nucleus of the hypothalamus in the regulation of cardiac and renal sympathetic nerve activity in conscious normal and heart failure sheep

R Ramchandra, SG Hood, R Frithiof, MJ McKinley, CN May

2013-01-01

The paraventricular nucleus of the hypothalamus (PVN) plays a major role in central cardiovascular and volume control, and has bee..

Effect of selective inhibition of renal inducible nitric oxide synthase on renal blood flow and function in experimental hyperdynamic sepsis

K Ishikawa, P Calzavacca, R Bellomo, M Bailey, CN May

2012-08-01

OBJECTIVE: Nitric oxide plays an important role in the control of renal blood flow and renal function. In sepsis, increased levels..

Renal bioenergetics during early gram-negative mammalian sepsis and angiotensin II infusion

CN May, K Ishikawa, L Wan, J Williams, RM Wellard, GS Pell, GD Jackson, R Bellomo

2012-05-01

Purpose: To measure renal adenosine triphosphate (ATP) (bioenergetics) during hypotensive sepsis with or without angiotensin II (A..

Central angiotensin type 1 receptor blockade decreases cardiac but not renal sympathetic nerve activity in heart failure

R Ramchandra, SG Hood, AMD Watson, AM Allen, CN May

2012-03-01

In heart failure (HF), cardiac sympathetic nerve activity (SNA; CSNA) is increased, which has detrimental effects on the heart and..

The effects of terlipressin on regional hemodynamics and kidney function in experimental hyperdynamic sepsis

K Ishikawa, L Wan, P Calzavacca, R Bellomo, M Bailey, CN May

2012-02-15

Background and Aims: Although terlipressin (TP) may improve renal function in cirrhotic patients, its use in sepsis remains contro..

Central Angiotensin Type 1 Receptor Blockade Decreases Cardiac But Not Renal Sympathetic Nerve Activity in Heart Failure

R Ramchandra, SG Hood, AM Watson, AM Allen, CN May

2012-01-01

Cardioprotection from ischaemia-reperfusion injury by a novel flavonol that reduces activation of p38 MAPK

CJ Thomas, DCH Ng, N Patsikatheodorou, Y Limengka, MWK Lee, IA Darby, OL Woodman, CN May

2011-05-11

Oxidative stress, activation of intracellular protein kinases and cardiomyocyte apoptosis are known mediators of cardiac ischaemia..

Water soluble flavonol prodrugs that protect against ischaemia-reperfusion injury in rat hindlimb and sheep heart

SJ Williams, CJ Thomas, M Boujaoude, CT Gannon, SD Zanatta, B Jarrott, CN May, OL Woodman

2011-04-01

Phosphate and hemiadipate derivatives of cardioprotective flavonols are water soluble prodrugs that release superoxide scavenging ..

Hypertonic sodium resuscitation after hemorrhage improves hemodynamic function by stimulating cardiac, but not renal, sympathetic nerve activity

R Frithiof, R Ramchandra, SG Hood, CN May

2011-02-01

Small volume hypertonic saline resuscitation can be beneficial for treating hemorrhagic shock, but the mechanism remains poorly de..

Maturation-related changes in the pattern of renal sympathetic nerve activity from fetal life to adulthood

LC Booth, L Bennet, SJ Guild, CJ Barrett, CN May, AJ Gunn, SC Malpas

2011-01-01

Sympathetic nerve activity (SNA) has two main properties, the presence of co-ordinated bursts of activity, indicative of many nerv..

The impact of intrarenal nitric oxide synthase inhibition on renal blood flow and function in mild and severe hyperdynamic sepsis

K Ishikawa, R Bellomo, CN May

2011-01-01

Objective: In experimental hyperdynamic sepsis, renal function deteriorates despite renal vasodilatation and increased renal blood..

Response of cardiac sympathetic nerve activity to intravenous irbesartan in heart failure

R Ramchandra, AMD Watson, SG Hood, CN May

2010-04-01

To determine the effect of irbesartan treatment on resting levels and arterial baroreflex control of cardiac sympathetic nerve act..

The impact of experimental hypoperfusion on subsequent kidney function

T Saotome, K Ishikawa, CN May, IE Birchall, R Bellomo

2010-03-01

Objective: To investigate the short- and medium-term renal hemodynamic and functional responses to both short and sustained hypope..

3′,4′-Dihydroxyflavonol improves post-ischaemic coronary endothelial function following 7 days reperfusion in sheep

S Wang, CJ Thomas, GJ Dusting, OL Woodman, CN May

2009-12-10

3′,4′-dihydroxyflavonol (DiOHF) is a potent antioxidant that reduces infarct size following myocardial ischaemia-reperfusion. Sinc..

Epidemiology of septic acute kidney injury

A Parmar, C Langenberg, L Wan, CN May, R Bellomo, SM Bagshaw

2009-12-01

The incidence of sepsis and acute kidney injury (AKI) is increasing in critically ill patients and both portend a higher risk of m..

Septic shock induces distinct changes in sympathetic nerve activity to the heart and kidney in conscious sheep

R Ramchandra, L Wan, SG Hood, R Frithiof, R Bellomo, CN May

2009-11-01

Sepsis and septic shock are the chief cause of death in intensive care units, with mortality rates between 30 and 70%. In a large ..

Discharge properties of cardiac and renal sympathetic nerves and their impaired responses to changes in blood volume in heart failure

R Ramchandra, SG Hood, R Frithiof, CN May

2009-09-01

Sympathetic nerve activity (SNA) consists of discharges that vary in amplitude and frequency, reflecting the level of recruitment ..

Angiotensin II in experimental hyperdynamic sepsis.

L Wan, C Langenberg, R Bellomo, CN May

2009-01-01

INTRODUCTION: Angiotensin II (Ang II) is a potential vasopressor treatment for hypotensive hyperdynamic sepsis. However, unlike ot..