Research Theme

Respiratory

Chronic respiratory diseases are a diverse group of conditions affecting the lungs or respiratory tract for a prolonged period. They are often incurable, but are largely manageable and preventable. Chronic respiratory diseases are very prevalent in Australia—an estimated 5.8 million Australians had at least one long-term respiratory condition in 2001.

Each year, chronic respiratory diseases disrupt the daily life and productivity of many individuals and contribute to thousands of deaths. Two major chronic respiratory diseases in Australia are chronic obstructive pulmonary disease (COPD), a mixture of chronic bronchitis and emphysema, and asthma (Source: AIHW 2005).

The Menzies Research Institute is working towards the prevention, treatment, and cure for respiratory disease.

Some examples of research projects within the Respiratory research theme at the Menzies Research Institute:

Physiology

The respiratory research group has developed novel measurement systems for airway stiffness and differentiation between large and small airway disease and lung parenchymal disease. These support our immunopathology studies by providing sophisticated physiological phenotype correlations ie. relationships between structural changes and disturbed function. We are working with large data-sets of lung function data for “mining” patterns of disease and determining mechanisms of exercise-related oxygen desaturation.

Airway disease immunopathology

This research involves bronchoscopic assessment and tissue sampling of smokers with normal and abnormal airflow.  We are assessing airway inflammation and airway structural remodelling and the mechanisms involved in linkage between the two in patients with chronic obstructive pulmonary disease (COPD).

Our group has a particular interest in a chemical “growth factor” called vascular endothelial growth factor and angiogenesis (new blood vessel formation) in the airways in situations of chronic inflammation, and the response to inhaled corticosteroid and smoking cessation, we are also studying a growth factors related to scarring, TGFβ1 as a central mediator linking airway cellular activation and inflammation with remodelling.

Cystic Fibrosis

One of the peculiarities of cystic fibrosis is that the airways become infected by a soil bacterium Pseudomonas aeuriginosa, which hardly ever occur in the lungs in other situations

The chemical environment of the airway that favours growth of the bacteria Pseudomonas aeruginosa especially involves the handling of ferrous/ferric iron. We are investigating iron-chelators as potential therapy. We are also looking at virulence factors in Pseudomonas and relationship to disease severity, plus the importance of biofilms and their modification to Pseudomonas infection.

In the area of health services research we are investigating the use of information technology and self-efficacy building in patient case management.

Evidence-Based Medicine

Our group is the headquarters of the Cochrane Collaboration Australian Airway Network providing systematic reviews (ie what do we really know about treatment?) in asthma and COPD to support national and international guideline development.

Health Services Research in COPD

Pathways Home for Chronic Respiratory Disease is a collaboration with the Department of Health and Human Services to develop clinical self-efficacy in patients with COPD, and to foster case-management through training of “mentors” based in community nursing.

We are conducting a study of usefulness and barriers to use of spirometry in case finding and management of COPD in general practice. We also have an interest in appropriate use of medicines in the community and use of information technology systems.

Spirometry in general practice

Spirometry is an important test of lung function and is included as part of practice guidelines for detecting and monitoring of patients with diseases such as asthma and chronic obstructive pulmonary disease. However, there is no data on the utility of this test in general practice in Australia.

In this study we obtained the first data on spirometer ownership and usage in Australia and have completed a parallel study showing that a newly developed ultrasonic spirometer is an ideal instrument for use by General Practitioners due to its accuracy and long-term stability of its calibration.

Epidemiology and Genetics

The Tasmanian Asthma Survey is a 36 year follow up of the 1961 Tasmanian birth cohort first studied in 1968 at age of seven years. We have spent five years finding the original probands and undertaking a comprehensive questionnaire survey and laboratory examination of lung function in 1,400 randomly selected probands. 

We are currently in the process of enriching the laboratory study for individuals in specific clinical phenotypes determined by the answers to the questionnaire.  We will be starting the next phase of the study in 2007 in which we will be undertaking a questionnaire and a physiological and genetic study of phenotypically matched and unmatched siblings.

We are a collaborating centre in the national Burden Of Lung Disease (BOLD) study, a multicentre Australian survey of COPD prevalence and risk factors.

Flow dependence of anatomical dead space measured with new ultrasonic technology

Under a confidentiality agreement with an instrument company (ndd, Medizintechnik, Switzerland) we have applied novel ultrasonic technology to show, for the first time, that the volume of the conducting airways of the lung (anatomical dead space) is inversely related to expiratory flow. We believe that this flow-dependence of anatomical dead space occurs due to non-uniform airway emptying which is greater at lower expired flows.

Our data offers the potential to derive new and sensitive information about disease driven geometric abnormalities of the peripheral airways, which may lead to new non-invasive and highly sensitive methods for detecting very early mechanical airway abnormalities, that is at a stage when it is potentially reversible.

Exercise induced arterial desaturation measured with arterial blood samples and pulse oximetry

This complex study aimed to determine the accuracy of pulse oximetry in assessing blood oxygenation during exercise in females and to determine whether any desaturation is due to diminished sensitivity to a drop in oxygen. Our results showed that pulse oximetry tends to underestimate arterial oxygenation and that arterial desaturation is not associated with reduced chemosensitivity to oxygen.

Relative vs absolute physiological measures as predictors of mountain bike cross-country race performance

The aims of this study were to document the effect terrain has on the physiological responses and work demands (power output) of riding a typical mountain bike cross-country course under race conditions and to compare this to performance during a an exercise test conducted in the laboratory. We found a strong relationship between the physiological variables determined from the laboratory test and performance during the cross-country time trial and also that the different terrain types encountered during the cross-country race elicited different physiological responses in the rider. The major finding of this study that physiological measures relative to mass obtained during the laboratory based testing were significantly more predictive of performance during the field trial than absolute measures has significant implications for training prescription.

For more information, contact:

Professor Haydn Walters

Senior Member

Telephone: (03) 6226 4805

Changes in Cystic Fibrosis mortality in Australia over the past 25 years

The Menzies Research Institute, the School of Medicine at the University of Tasmania and the Royal Adelaide Hospital are working in collaboration on a study that will investigate Cystic Fibrosis survival and mortality trends in Australia for the period 1979 to 2004.

It has been reported in the medical literature that in developed countries, improved care and specialized CF treatment centers have increased survival for people with Cystic Fibrosis over the past three decades. However there is little published data looking at mortality trends in Australia. This study will look at Cystic Fibrosis mortality rates according to age, gender and state of usual residence.

For more information, contact:

 

Associate Professor Leigh Blizzard

Senior Biostatistician

Telephone: (03) 6226 7719