The Final Common Channel: Measurement Of Nerve Excitability In Epilepsy.
Funder
National Health and Medical Research Council
Funding Amount
$301,376.00
Summary
Epilepsy may be due to either one single genetic mutation or a combination of several gene-environment interactions, affecting how ion channels function. It is not possible to directly interrogate channels in the living human brain but, because similar channels are found in peripheral nerve, much may be learned about aberrant channel function from peripheral nerve. This project aims to measure peripheral nerve excitability in epilepsy patients, using it as a marker of the final common pathway of ....Epilepsy may be due to either one single genetic mutation or a combination of several gene-environment interactions, affecting how ion channels function. It is not possible to directly interrogate channels in the living human brain but, because similar channels are found in peripheral nerve, much may be learned about aberrant channel function from peripheral nerve. This project aims to measure peripheral nerve excitability in epilepsy patients, using it as a marker of the final common pathway of channel dysfunction.Read moreRead less
Role Of Transition Metal Ions And Redox Activity In The Development Of Atherosclerotic Plaques
Funder
National Health and Medical Research Council
Funding Amount
$196,018.00
Summary
Metal ions such as iron and copper have been reproted to be present in the lesions present in diseased human arteries and it has been suggested that these metal ions contribute to the development of atherosclerosis (hardening of the arteries) via their ability to catalyse the formation of highly reactive molecualr fragments called free radicals. Though metal ions are known to catalyse such reactions in test-tube experiments, both the presence of metal ions in diseased arteries and their ability ....Metal ions such as iron and copper have been reproted to be present in the lesions present in diseased human arteries and it has been suggested that these metal ions contribute to the development of atherosclerosis (hardening of the arteries) via their ability to catalyse the formation of highly reactive molecualr fragments called free radicals. Though metal ions are known to catalyse such reactions in test-tube experiments, both the presence of metal ions in diseased arteries and their ability to generate free radicals is controversial. This study will employ a novel, minimally-invasive, technique to assess the nature and quantity of metal ions present in well-defined human and animal lesions at different stages of lesion development. The ability of these metal ions to catalyse free radical formation from components present in the artery wall will also be assessed. The release of these metal ions from the artery wall to added organic molecules will be assessed as this might minimise their potential to cause damage, and provide a possible therapeutic strategy. These studies will therefore provide valuable information as to the significance and role of reactive metal ions in the development of human artery disease and the possible prevention, or minimisation, of such processes.Read moreRead less
Mitochondrial Iron Overload And Friedreich's Ataxia: The Role Of Frataxin In Iron And Haem Metabolism
Funder
National Health and Medical Research Council
Funding Amount
$606,000.00
Summary
Friedreich's ataxia (FA) is due to the lack of a protein known as frataxin. A variety of studies using Baker's yeast and conditional frataxin knockout (KO) mice have shown that deletion of frataxin leads to the accumulation of toxic iron in their mitochondrion. More recently, a variety of studies have shown that FA patients have iron-loading within their mitochondrion. Iron in the highly redox active environment of the mitochondrion could contribute to the generation of cytotoxic radicals that c ....Friedreich's ataxia (FA) is due to the lack of a protein known as frataxin. A variety of studies using Baker's yeast and conditional frataxin knockout (KO) mice have shown that deletion of frataxin leads to the accumulation of toxic iron in their mitochondrion. More recently, a variety of studies have shown that FA patients have iron-loading within their mitochondrion. Iron in the highly redox active environment of the mitochondrion could contribute to the generation of cytotoxic radicals that cause severe damage. Further, cells deficient in frataxin are sensitive to oxidant stress and Fe chelators rescue oxidant-mediated death of cells from FA patients. Indeed, free radical scavengers have shown to be of use in the treatment of this disease. Studies in DR's lab during this NHMRC grant have shown that frataxin is down-regulated by erythroid differentiation or the haem precursor, protoporphyrin IX (BLOOD 2002;99:3813-22). These data indicate a role for frataxin in Fe metabolism and the pathogenesis of FA. In this study we will continue to examine the role of frataxin in the way cells handle Fe using experimental models developed under the current NHMRC grant. These include transfected cell lines with low frataxin expression generated using an expression vector containing anti-sense frataxin cDNA. Further we obtained the frataxin conditional KO mouse and generated a breeding colony. These animals display many of the pathological features of FA and are the best current model of the disease. Indeed, they will be critical for assessing the role of frataxin in Fe metabolism and as a model to test the ability of Fe-binding drugs to prevent the pathology observed. We designed lipid-soluble chelators that can enter the mitochondrion to bind Fe (Biochim Biophys Acta 2001;1536:133-140) and these ligands will be tested to prevent disease progression in the KO mice. This exciting research is crucial for understanding the pathogenesis of FA and in creating new therapies.Read moreRead less
EPITHELIAL ION TRANSPORT DEFECTS IN CYSTIC FIBROSIS: PATHOPHYSIOLOGY AND TREATMENT
Funder
National Health and Medical Research Council
Funding Amount
$290,440.00
Summary
The thin layer of fluid covering the surface of the air passages acts to protect the airway surface from drying. This fluid also allows the hair-like projections, or cilia, on the top of the airway cells to beat more effectively. The volume and composition of this fluid is determined by the movement of salt and water across the mucous membranes of the air passages. The importance of this fluid is shown by the problems that occur in Cystic Fibrosis (CF), the most common lethal inherited disease a ....The thin layer of fluid covering the surface of the air passages acts to protect the airway surface from drying. This fluid also allows the hair-like projections, or cilia, on the top of the airway cells to beat more effectively. The volume and composition of this fluid is determined by the movement of salt and water across the mucous membranes of the air passages. The importance of this fluid is shown by the problems that occur in Cystic Fibrosis (CF), the most common lethal inherited disease affecting Australians. In CF, altered salt transport causes drying of the airway surface which impairs the working of the cilia. This leads to retention of mucous in the airway with repeated bacterial infections damaging the lungs. Simple tests have been designed to directly measure the movement of salt across the surface of the nasal passage using a fine soft rubber tube. Movement of mucous in the nose is measured using other simple techniques that are currently used diagnostically. Together, these tests in the nose provide vital information about how the surface of normal human airway moves salt, water and mucous. Any differences found in CF patients will then give us a good idea of the problems found in the CF lung. We will study the interactions between calcium, sodium and chloride in the fluid lining the airways, measuring changes in salt and mucous movement. A range of testing procedures will be used in human volunteers, anaesthetised mice and isolated tissues from sheep. We have already demonstrated important links between the fluid lining the airways and salt movement, and we expect that this may lead to the development of new treatments for Cystic Fibrosis. This therapy will focus on treating the lung problems of CF patients, the major cause of disability. We anticipate that this preventative therapy may offer real benefits in the fight to cure CF.Read moreRead less