How Do Thick Airway Walls Affect Airway Hyperresponsiveness In Asthma?
Funder
National Health and Medical Research Council
Funding Amount
$382,538.00
Summary
Asthmatic airways narrow too easily, a characteristic called airway hyperresponsiveness (AHR). To understand the cause of asthma we need to understand the cause of AHR. Thickened airway walls could amplify airway narrowing and increase AHR. However, thick airway walls are also stiff, and stiff walls could reduce narrowing and AHR. This project will examine the relationships between AHR and airway wall thickness and stiffness during and after treatment that reduces airway wall thickness.
THE BAROREFLEX IN SNORING AND THE OBSTRUCTIVE SLEEP APNOEA HYPOPNOEA SYNDROME
Funder
National Health and Medical Research Council
Funding Amount
$436,261.00
Summary
The obstructive sleep apnoea hypopnoea syndrome (OSAHS) refers to a condition in which throat blockage occurs during sleep leading to breathing difficulties, including snoring and cessation of breathing for short periods of time. OSAHS is amongst the commonest of chronic disorders of adult males, occuring in 5% of men over the age of 45 years. It is now recognised that one of the major complications of OSAHS is the development of high blood pressure and heart disease. In the proposed studies, we ....The obstructive sleep apnoea hypopnoea syndrome (OSAHS) refers to a condition in which throat blockage occurs during sleep leading to breathing difficulties, including snoring and cessation of breathing for short periods of time. OSAHS is amongst the commonest of chronic disorders of adult males, occuring in 5% of men over the age of 45 years. It is now recognised that one of the major complications of OSAHS is the development of high blood pressure and heart disease. In the proposed studies, we will examine the proposal that snoring alone, without significant associated OSAHS, can also lead to high blood pressure in habitual snorers both awake and asleep. In particular, we will explore the hypothesis that chronic snoring transmits a pressure wave through the tissues of the neck to the carotid artery which is the main blood supply to the brain. We propose that the chronic vibration of this artery can alter pressure sensors in the artery wall, which then results in the persistance of high blood pressure. Our studies will help to prove that this is a mechanism whereby both snoring and OSAHS may contribute to the development of high blood pressure. The recognition of snoring as an independent risk factor for high blood pressure will clearly have important and wide ranging implications for the future management of snoring in the prevention of high blood pressure.Read moreRead less
Clinical Impact Of Clonal Pseudomonas Aeruginosa In Cystic Fibrosis
Funder
National Health and Medical Research Council
Funding Amount
$547,238.00
Summary
In patients with cystic fibrosis (CF), the normal defence mechanisms are compromised by an inherent genetic fault which results in an extremely sticky and dehydrated mucus. The respiratory system is unable to eradicate microbes (infection) from the lungs of patients with CF which begin to multiply and cause infection and inflammation. Recurring infections are treated with multiple courses of antibiotics and frequent hospitalisation and eventually result in premature death. This study focuses on ....In patients with cystic fibrosis (CF), the normal defence mechanisms are compromised by an inherent genetic fault which results in an extremely sticky and dehydrated mucus. The respiratory system is unable to eradicate microbes (infection) from the lungs of patients with CF which begin to multiply and cause infection and inflammation. Recurring infections are treated with multiple courses of antibiotics and frequent hospitalisation and eventually result in premature death. This study focuses on the major bacterial problem, Pseudomonas aeruginosa. Several studies from Australia and the UK, including our own have shown that about 30% to 45% of patients share the same strain of Pseudomonas aeruginosa within a centre. We know that two dominant strains of Pseudomonas aeruginosa are found in CF centres on the eastern board of Australia. This is unexpected as this bacterium is usually acquired from the environment. The emergence of these clonal strains is causing increasing anxiety in the CF community. This study is designed to provide vitally needed information on the clinical implications of being infected by an clonal strain of Pseudomonas aeruginosa and the risk factors for the acquisition of an clonal strain. This new information will provide a rationale basis for the need for changes to infection control policies (including patient segregation), better outcome predictors for patients infected with clonal strain of Pseudomonas aeruginosa.Read moreRead less
Impact Of DTP Schedules On The Immunogenicity Of 2 Doses Of 13v-PCV Followed By An Early Booster
Funder
National Health and Medical Research Council
Funding Amount
$2,651,687.00
Summary
This project aims to come up with a vaccination schedule to make pneumococcal vaccines more effective and affordable for Fiji and other developing countries. We will evaluate schedules involving a 2 dose primary series in early infancy with a booster at 9 months of age. We will compare the immune responses to 3 different primary series and 2 booster options. The results of this project will be used to provide advice, at global and country levels, regarding introduction of pneumococcal vaccines.
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
$285,990.00
Summary
Friedreich's ataxia (FA) is due to the lack of a protein known as frataxin. Recent studies using Baker's yeast have shown that the deletion of frataxin results in the accumulation of toxic iron in the mitochondrion. More recently, a variety of studies have shown that FA patients have iron loading within their cells. The iron build-up may cause severe damage. At present, the role of frataxin in mammalian mitochondrial iron metabolism is unknown. Our preliminary studies demonstrate that frataxin i ....Friedreich's ataxia (FA) is due to the lack of a protein known as frataxin. Recent studies using Baker's yeast have shown that the deletion of frataxin results in the accumulation of toxic iron in the mitochondrion. More recently, a variety of studies have shown that FA patients have iron loading within their cells. The iron build-up may cause severe damage. At present, the role of frataxin in mammalian mitochondrial iron metabolism is unknown. Our preliminary studies demonstrate that frataxin is down-regulated by either erythroid differentiation or the haem precursor protoporphyrin IX (Becker and Richardson, submitted). These data strongly suggest a role for frataxin in iron metabolism. In the present study we will continue to assess if frataxin plays a role in the way cells handle iron. Using a unique model of mitochondrial iron overload developed in my lab (Richardson et al. (1996) BLOOD 87:3477), we will extensively investigate the iron metabolism of the mitochondrion in order to determine the function of frataxin and its role in Friedreich's ataxia. In addition, we have developed a series of new drugs known as iron chelators that can enter the mitochondrion due to their high lipid solubility (Becker and Richardson 1999 J. Lab. Clin. Med. 134:510). These latter drugs are far more effective than the chelator currently used to treat iron overload, desferrioxamine (DFO). Indeed, our chelators have been designed to result in high iron chelation efficacy but low toxicity (see Becker and Richardson, 1999). This exciting research may be crucial in understanding the development of FA and in creating new therapies such as the use of iron chelators.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
Molecular Mechanisms Of Receptor Activation And Signalling
Funder
National Health and Medical Research Council
Funding Amount
$571,980.00
Summary
Fundamental to our ability to respond to both immediate and long-term environmental changes and stresses is the coordinated regulation of cellular functions by hormonal and neurotransmitter stimuli. The great majority of such stimuli are sensed by G-protein coupled receptors (GPCR), complex glycoprotein molecules on the surface of most cells that selectively bind and are activated by various hormones and neurotransmitters. Although GPCRs are a superfamily of proteins that now compromise several ....Fundamental to our ability to respond to both immediate and long-term environmental changes and stresses is the coordinated regulation of cellular functions by hormonal and neurotransmitter stimuli. The great majority of such stimuli are sensed by G-protein coupled receptors (GPCR), complex glycoprotein molecules on the surface of most cells that selectively bind and are activated by various hormones and neurotransmitters. Although GPCRs are a superfamily of proteins that now compromise several hundred distinct but structurally-related members, the molecular mechanisms involved in their activation and, thus, their regulation of vital cellular functions, remains unclear. Based on insights that we have gained from the development and characterisation of several alpha1-adrenergic receptor mutants, we have developed a model of receptor activation. In this application we are proposing to further test and to extend the hypotheses underlying this model. Importantly, the functions regulated by GPCR include vital responses, such as the maintenance of circulatory homeostasis by augmenting heart pump function and by constricting vascular smooth muscle to maintain blood pressure. In addition, disordered cellular regulation by GPCR has been implicated in a wide variety of diseases, including hypertension, congestive heart failure and cardiac hypertrophy. Thus, the studies detailed here to further understand the molecular mechanisms of receptor activation have broad implications for our knowledge of critical physiological control systems, and may lead to novel therapeutic approaches to treat a variety of diseases.Read moreRead less
A NOVEL MOUSE MODEL TO INVESTIGATE THE MECHANISMS OF VIRUS-INDUCED ARTHRITIS
Funder
National Health and Medical Research Council
Funding Amount
$336,000.00
Summary
We have developed a novel animal model by which to study arthritic disease caused by insect-transmitted viruses known as arboviruses. The existence of this model and novel reagents provides an excellent opportunity to further explore the basic mechanisms of infectious disease in a complete functioning animal, rather than specific cultured cells. The study will use modern approaches in molecular and cellular biology to achieve this goal. The production by our immune systems of soluble mediators ( ....We have developed a novel animal model by which to study arthritic disease caused by insect-transmitted viruses known as arboviruses. The existence of this model and novel reagents provides an excellent opportunity to further explore the basic mechanisms of infectious disease in a complete functioning animal, rather than specific cultured cells. The study will use modern approaches in molecular and cellular biology to achieve this goal. The production by our immune systems of soluble mediators (cytokines-chemokines) and antibodies is an overwhelming positive aspect of our physiological response to infection by microbes. Protection from disease by these immune compounds can happen naturally, or the body's ability to produce these factors can be exploited to our benefit via the administration of vaccines. However, these factors can also be detrimental to the host contributing to severe disease. For instance, work performed almost 40 years ago showed for the first time that under particular conditions, antibodies against viruses can enhance infection, instead of inhibiting infection as normally seen. In the intervening years work by scientists all over the world has associated antibody-dependent enhancement (ADE) of infection to many types of viruses; ADE is even thought to be a risk factor to serious disease with dengue virus, and has been shown in vitro for the AIDS virus and Ebola virus. We have recently discovered a molecular mechanism which explains how antibody enhances viral infection in vitro. In studies on immune cells infected with Ross River Virus (RRV) we found that infection helped by antibody resulted in the specific disruption to the production of cellular chemicals which are toxic to viruses. Are these mechanisms of antibody-enhanced infection also found in animals? Will such mode of infection cause enhanced disease and tissue pathology (arthritis) in animals?Read moreRead less
Development Of Iron Chelators For The Treatment Of Friedreichs Ataxia And The Role Of Frataxin In Iron Metabolism
Funder
National Health and Medical Research Council
Funding Amount
$550,987.00
Summary
Friedreich's ataxia (FA) is a neuro- and cardio-degenerative disease where there is an accumulation of toxic Fe in the mitochondrion. Excitingly, work from our current NHMRC grant showed iron plays a significant role in FA pathology. Importantly, we developed new drugs (Fe chelators) which rescue the cardiac pathology of FA in an animal model. Studies will now assess if our drugs prevent the neurodegeneration of FA in another animal model. This work could lead to novel therapies for FA.