Julia Raftos

Biography

Senior Lecturer at Macquarie University

Research Interest

My current interest is in the anti-oxidant systems in the human red blood cell and at present my studies centre around the antioxidant glutathione. Red blood cells are especially vulnerable to oxidative damage because of their role in oxygen transport. Every day up to 3% of the haemoglobin in the red cell is oxidised and this process releases oxygen radicals that have the potential to react with cell proteins and lipids producing a cascade of events that can disrupt the function of critical cell constituents. Without a nucleus the red blood cell cannot replace these damaged components. These cells are also exposed to oxidants that are released into the blood by activated cells of the immune system and from sites of inflammation. As red blood cells circulated through all tissues and organs their anti-oxidant systems have a significant function in maintaining the redox state of the whole body. Glutathione plays a particularly important role in detoxifying peroxides. Low red cell glutathione levels are associated with several chronic diseases ranging from pulmonary diseases to sickle cell anaemia. Restoration of normal glutathione concentrations reduces tissue damage and the resultant pathology. I am particularly interested investigating the way glutathione levels are controlled within red cells. Glutathione metabolism involves the action of several enzymes and the membrane transport proteins that supply the substrates required to produce glutathione. In order to obtain a quantitative understanding of the interaction of these processes in maintaining appropriate glutathione levels we have developed a mathematical model of glutathione metabolism. This model was written in Mathematica and verified by comparing model outcomes with experimental results. We use the model combined with experimental measurement to identify the underlying causes of glutathione deficiency in situations ranging from disease states to long-term storage of red blood cells prior to transfusion.