I am a physiologist investigating the role of molecular rhythmicity in physiological systems. My work focuses on the impact of disrupted rhythmicity on metabolism, cancer and fertility at the cellular level and is of particular importance when considering
Phase Shifting Endocrine And Sleep/activity Rhythms With Light And Serotonergic Drugs
Funder
National Health and Medical Research Council
Funding Amount
$561,430.00
Summary
All biological systems, including those of humans, are influenced by changes in the environment, especially by variations in the amount of daylight. In animals the external rhythm of light and darkness interacts with a small part of the brain called the suprachiasmatic nucleus (SCN-often called the biological clock) which has its own self sustained rhythms. The SCN in turn orchestrates rhythms in the secretion of the hormone melatonin from the pineal gland, body temperature, the timing of sleep ....All biological systems, including those of humans, are influenced by changes in the environment, especially by variations in the amount of daylight. In animals the external rhythm of light and darkness interacts with a small part of the brain called the suprachiasmatic nucleus (SCN-often called the biological clock) which has its own self sustained rhythms. The SCN in turn orchestrates rhythms in the secretion of the hormone melatonin from the pineal gland, body temperature, the timing of sleep and the secretion of other hormones. The aim of this study is to extend our knowledge of the inter-relationships between light, the chemical messengers that nerves use to communicate with each other, the biological clock and rhythms in body functions. We will concentrate on one particular chemical messenger called serotonin which we believe plays an important role in keeping rhythms in synchrony with the natural day-night cycle. The results are expected to be of benefit in understanding how certain sleep timing disorders arise and provide some insight into how they might be treated.Read moreRead less
Acute Alerting Effects Of Daytime Exposure To Specific Wavelengths Of Light
Funder
National Health and Medical Research Council
Funding Amount
$446,367.00
Summary
Excessive sleepiness is the greatest identifiable and preventable cause of accidents in all modes of transportation. Shift workers working outside the 8am-5pm day, make up about 20% of the urban working population. These individuals often report excessive daytime sleepiness caused by irregular sleep-wake patterns and long-term sleep loss. Excessive sleepiness is also common in individuals with sleep disorders. While there are many stimulant and wake-promoting drugs available to counteract daytim ....Excessive sleepiness is the greatest identifiable and preventable cause of accidents in all modes of transportation. Shift workers working outside the 8am-5pm day, make up about 20% of the urban working population. These individuals often report excessive daytime sleepiness caused by irregular sleep-wake patterns and long-term sleep loss. Excessive sleepiness is also common in individuals with sleep disorders. While there are many stimulant and wake-promoting drugs available to counteract daytime fatigue such drugs have problems of side effects, interactions and in some cases dependence. Light has many beneficial effects for a wide range of medicinal, physiological, psychological, and social purposes. One well known effect is as a stimulant so that exposure to bright light, both during the night and in the middle of the day, improves alertness and attention, and decreases reaction times thus improving performance. These effects can also be measured as changes in brain activity. However we do not understand the mechanisms in the eyes which control these effects. While certain cells in the eyes called rods and cones are necessary for seeing objects clearly and for detecting colour, there appears to be another system in the eyes which may involve different specialized cells or photoreceptors that are important for the alerting effects of light. White light is made up of different wavelengths or colours of light. This study will examine which wavelength (blue, violet, red or green) of light best improves alertness and learning during the daytime. Various performance tests will be used in addition to measures of brain wave activity. By identifying the most effective wavelength of light for improving alertness in healthy young adults and better understanding the mechanisms in the eyes involved, we will be able to develop light treatment strategies in patient groups with sleep disorders and in individuals like shift workers who experience sleep loss.Read moreRead less
Randomised Controlled Trial Of A Light Intervention To Enhance Alertness And Performance In Night Shiftworkers
Funder
National Health and Medical Research Council
Funding Amount
$708,736.00
Summary
Shiftworkers commonly experience high levels of fatigue during night shift, with decreased alertness and performance levels, placing them at high risk for accidents and injuries. Despite the large number of shiftworkers in Australia, effective fatigue management tools are lacking. Light increases alertness, and may provide an unobtrusive means to increase safety in shiftworkers. We will study the effectiveness of a novel method of light exposure to improve alertness in night shiftworkers.
The Impact Of Circadian Disturbances On Sleep Quality, Cognition And Psychiatric Symptoms In Neurodegenerative Disease
Funder
National Health and Medical Research Council
Funding Amount
$496,340.00
Summary
There is an increasing awareness that neurodegenerative diseases are associated with disturbances in sleep. Our group have recognised that patterns of sleep disturbance in these patients are also related to problems with memory and mood. The proposed study will be the first of its kind to explore whether disruptions in the circadian system represent a common mechanism underlying these comorbid disease features. Understanding this pathology will hopefully lead to the development of new therapies.
Comparing Light And Cognitive-behavior Therapies For The Treatment Of Sleep Maintenance Insomnia In Older Adults
Funder
National Health and Medical Research Council
Funding Amount
$383,961.00
Summary
Chronic insomnia affects more than 1 million Australians over 55 years of age. The most common treatment is sleeping pills despite their negative side effects. Our proposal is to compare non-drug cognitive-behaviour treatment with a new therapy of evening bright light, the combination of the two expected to be superior to either therapy alone. The project aims to improve the treatment of chronic insomnia in older adults leading to improved quality of life and reduced health care costs.
How Does Disruption Of Circadian Rhythms Induce Diabetes?
Funder
National Health and Medical Research Council
Funding Amount
$631,782.00
Summary
Increasing evidence suggests that disturbed circadian rhythms initiate and amplify metabolic and cardiovascular disease. The increasing and already high proportion of workers engaged in shiftwork, and increased frequency of disruption of these rhythms in the population more generally, implicate this body system as contributing to the growing epidemic of obesity and diabetes and related disorders in our community and world-wide. While we are now beginning to understand how our rhythms are synchro ....Increasing evidence suggests that disturbed circadian rhythms initiate and amplify metabolic and cardiovascular disease. The increasing and already high proportion of workers engaged in shiftwork, and increased frequency of disruption of these rhythms in the population more generally, implicate this body system as contributing to the growing epidemic of obesity and diabetes and related disorders in our community and world-wide. While we are now beginning to understand how our rhythms are synchronised to night and day, how this rhythmicity is linked to our organs in the normal and common disease states such as diabetes is poorly understood. The discovery of a special set of genes, called clock genes that function in all of the cells in our bodies and strongly influence the function of our organs such as the liver, pancreas and heart has been particularly important. We hypothesise that both environmentally (exogenous) and genetically (endogenous) induced disruption of circadian rhythms causes metabolic dysfunction. This is due to altered central and peripheral clock gene expression rhythms, which in turn alter metabolic rhythms and impair glucose homeostasis. This project aims to determine the impact of disrupted rhythmicity on metabolism with a particular emphasis on the possibility that the disrupted rhythmicity may be a predisposing factor for the development of diabetes.Read moreRead less