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Research Interests

My recent PhD studies, postdoctoral research and collaborations with the Department of Biochemistry have stimulated my interest in the significance of oxidative stress in determining renal and cardiovascular diseases. It is my intention to pursue these lines of research as my career progresses. This would be extended to acute and chronic renal failure which are serious problems resulting in damage or disturbances in the renal microvasculature and may frequently contribute to hypertension, oedema and heart failure.

The subject of my PhD project was to investigate the role of oxidative stress in determining the level of regional blood flow in the cortex and medulla of the kidney both normally and in a rat model of hypertension.  This was done in acutely anaesthetised animals prepared for measurement of cortical and medullary blood perfusions using laser-Doppler flowmetry and infusion of drugs into the cortico-medullary border area of the kidney.  It was found that elevating SOD activity within the kidney using Tempol (SOD mimetic) or inhibiting the enzyme with DETC (SOD inhibitor) elicited marked increases or decreases in medullary but not cortical perfusions.  Moreover, these responses were of greater magnitude in the rat model of hypertension suggesting that in this situation oxidative stress was greater and impacting on the level of blood perfusion into the medullary areas of the kidney.  This approach was extended to test whether H2O2 was involved and this was done by the intra-medullary infusion of tempol plus catalase, to break down any H2O2 produced.  The medullary vasodilator response was enhanced compared to the tempol, suggesting that H2O2 itself was having a vasoconstrictor action.  The final part of my study was to examine the effect of the acute inhibition of the NOS enzyme with and L-NAME on blood perfusion in the cortex and medulla.  It became evident that the local administration of L-NAME not only increased blood pressure but significantly reduced medullary, but not cortical, blood perfusion.

To date, the role of oxygen radicals in the regulation of proximal tubular fluid reabsorption has been relatively unexplored.  Several recent reviews have highlighted the uncertainty of the role of NO in the regulation of fluid transport across the proximal tubular epithelial cells and particularly its interaction with the reactive oxygen species.  Previous studies within the laboratory has provided some clarification as it has focussed attention on the renal sympathetic nerves as being crucially involved in allowing NO to exert its effect.  Moreover, the uncertainty expressed in these reviews could be due to the differing levels of oxygen radical formation caused by the different experimental conditions, thereby altering endogenous levels of NO and its ability to respond to experimental challenges.  This is the area of research that I intend to develop in the future.

In addition to the papers listed on the following page, I am currently preparing two more manuscripts for publication on the effects of oxidative stress on renal microvasculature in normal and spontaneously hypertensive rats.

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Peer Reviewed Journals

Conference Publications

	Year	Publication
	(2012)	Royal Academy of Medicine in Ireland Meeting H. Shabana, A. Ahmeda, E.J. Johns (2012) The impact of high salt diet on the regional renal haemodynamic Royal Academy of Medicine in Ireland Meeting [Details]
	(2013)	Royal Academy of Medicine Ireland, Section of Biomedical Sciences Annual Meeting 2013 H. F. Shabana, A. F. Ahmeda, E J Johns (2013) The Impact of High Salt Diet on the Regulation of Renal Hemodynamics and Nitric Oxide in Wistar Rats Royal Academy of Medicine Ireland, Section of Biomedical Sciences Annual Meeting 2013 [Details]
	(2011)	Oxford, UK, Physiological Society Meeting Shabana, H.F; Ahmeda, A.F; Johns, E.J (2011) The impact of NAD(P)H oxidase on the regulation of renal hemodynamics Oxford, UK, Physiological Society Meeting [Details]
	(2011)	Washington, DC. The FASEB Journal. 2011;25:824.8 O'Connor, F; Johns, E; Ahmeda, A (2011) Interaction between the Renin-Angiotensin System (RAS) and Reactive Oxygen Species (ROS) Washington, DC. The FASEB Journal. 2011;25:824.8 USA, , pp.824-824 [Details]
	(2010)	Manchester, UK, Physiological Society Meeting O'Connor, F.B; Ahmeda, A.F (2010) Consequences of blocking Superoxide Dismutase (SOD) on renal haemodynamics in functioning and blocked Angiotensin (Ang) system in rats Manchester, UK, Physiological Society Meeting UK, [DOI] [Details]
	(2010)	Molecules to Medicine, College of Medicine & Health, UCC O'Connor, F; Ahmeda, A (2010) Angiotensin II (Ang II) and oxidative stress Molecules to Medicine, College of Medicine & Health, UCC [Details]
	(2009)	Dublin, Ireland, Physiological Society Meeting Ahameda, A, O'Reilly, E; Johns,E (2009) Regulation of renal haemodynamics by reactive oxygen species in anaesthetized rats: a direct or indirect action via nitric oxide? Dublin, Ireland, Physiological Society Meeting Dublin, , 01-JUL-09 - 04-JUL-10 [Details]
	(2009)	Irish Society of Gastroenterology (ISG) Conference Abu Shanab, A; Ahmeda, A; Murphy, E; OMahony, L; Bennett, M; Shanahan, F; Quigley, EMM (2009) Impact of small intestinal bacterial overgrowth (SIBO) on bacterial translocation and liver histology Irish Society of Gastroenterology (ISG) Conference Killarney- Ireland, Irish Society of Gastroenterology (ISG) Conference, [Details]
	(2009)	Translational Health Research, College of Medicine & Health, UCC Ahmeda, A; O'Reilly, E; Johns, E (2009) Renal haemodynamics and superoxide anions: direct or indirect actions via nitric oxide? Translational Health Research, College of Medicine & Health, UCC [Details]
	(2006)	London, UK, Physiological Society Meeting Ahmeda, Ahmad F; Johns, Edward J; (2006) Influence of superoxide anions in the neural control of intra-renal haemodynamics of anaesthetised normotensive and hypertensive rats London, UK, Physiological Society Meeting London, [Details]
	(2005)	Bristol, UK, Physiological Society Meeting Ahmeda, Ahmad F; Johns, Edward J; (2005) Role of nitric oxide in neural control of intra-renal homodynamic in anaesthetised normotensive and hypertensive rats Bristol, UK, Physiological Society Meeting Bristol, [Details]
	(2004)	Cork, Ireland, Physiological Society Meeting Ahmeda, Ahmad F; Johns, Edward J; (2004) Role of oxidative stress on the renal microvasculature of anaesthetised wistar and stroke prone spontaneously hypertensive rats (SHRSP) Cork, Ireland, Physiological Society Meeting Cork, [Details]

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Teaching Interests

Module Co-ordinator GM2001 and PL3023

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Undergraduate:

PL2034 (Physiology for Dental Students)
PL3023 (Renal Physiology for Physiology Students)
PL3006 (Library Project Module for Physiology Students)
PL4004 (Final Year Project for Physiology Students)
FM2002 (Physiology for Medical Students, Direct Entry)

Graduate Entry to Medicine:GM1001, GM1002, GM1003 and GM2001 (Fundamentals of Medicine Years I and II)Small group learning/case based learning: GM1001, GM1002 and GM1003 (Fundamentals of Medicine Years I and II) 

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