Central Aortic Blood Pressure In Children: Establishing A Gold Standard Non-invasive Assessment Of Cardiovascular Risk
Funder
National Health and Medical Research Council
Funding Amount
$694,342.00
Summary
The best way of assessing early risk of cardiovascular disease involves measuring blood pressure near the heart (central pressure), but existing devices used in adults for this purpose are inaccurate in children. We will develop a children-specific method and apply it to study early cardiovascular risk in a comprehensive health study of 2000 children Australia-wide. We will also investigate why children with congenital heart disease frequently develop ‘older-adult’ heart disease at a young age.
Sympathetic Control Of Cutaneous Blood Flow And Blood Pressure In Human Spinal Cord Injury
Funder
National Health and Medical Research Council
Funding Amount
$242,002.00
Summary
While spinal cord injury can cause devastating changes in the nervous system paralysis and loss of sensation relatively little is known about changes to the sympathetic nervous system. The sympathetic nervous system is intimately involved in the ongoing control of blood pressure, blood flow and temperature control. Loss of sympathetic control can occur following spinal cord injury. Interruption of descending pathways can result in partial or complete loss of sympathetic outflow from the thoracol ....While spinal cord injury can cause devastating changes in the nervous system paralysis and loss of sensation relatively little is known about changes to the sympathetic nervous system. The sympathetic nervous system is intimately involved in the ongoing control of blood pressure, blood flow and temperature control. Loss of sympathetic control can occur following spinal cord injury. Interruption of descending pathways can result in partial or complete loss of sympathetic outflow from the thoracolumbar segments. Complete decentralization can result in autonomic dysreflexia (autonomic hyperreflexia), in which sensory stimuli originating below the lesion evoke a reflex increase in sympathetic drive to the blood vessels, causing them to constrict. Because of this, blood pressure may rise suddenly and remain at such high levels that stroke and (occassionally) cardiac arrest may occur. This phenomenon, autonomic dysreflexia, is considered a medical emergency. The typical subjective signs of autonomic dysreflexia include a throbbing headache, tingling in the head or nasal congestion; sweating and flushing above the lesion are clinical signs that prompt medical staff to measure blood pressure and to locate the source of sensory irritation (usually a distended bladder or impacted colon, sometimes a pressure sore or ingrown toenail). Commonly, however, subclinical episodes go undetected, and this phenomenon of silent dysreflexia is of increasing concern. This project will develop means of assessing the integrity and state of the sympathetic nervous system below a lesion in patients with spinal cord injury and characterize the firing properties of reflexly activated sympathetic neurones.Read moreRead less
The Effects Of Tonic Muscle Pain On The Sympathetic And Somatic Motor Systems In Human Subjects
Funder
National Health and Medical Research Council
Funding Amount
$462,948.00
Summary
The main objective of this proposal is to reveal the effects of nociceptive reflexes in humans, and thus identify their functional and clinical implications. By performing invasive recordings from the nerves that control blood vessels and muscles in healthy volunteers subjected to long-lasting (~1 hour) experimental pain, this work will increase our understanding of the adaptive changes that pain induces and improve treatments to prevent pain from becoming chronic.
FUNCTIONAL IMAGING OF THE BRAINSTEM AND CORTICAL SITES OF BLOOD PRESSURE CONTROL IN HUMAN SUBJECTS IN HEALTH AND DISEASE
Funder
National Health and Medical Research Council
Funding Amount
$398,498.00
Summary
Disturbances in cardiovascular control underpin many diseases yet little is known about how the brain controls the heart and blood vessels. This project uses brain imaging (fMRI) and concurrent nerve recording in awake human subjects to increase our understanding of how normal blood pressure is maintained and how different disease states influence this control.
Pressures Exerted On Upper Airway Walls By Surrounding Tissue Structures
Funder
National Health and Medical Research Council
Funding Amount
$426,500.00
Summary
The obstructive sleep apnoea syndrome (OSA) refers to a condition in which throat blockage occurs during sleep leading to breathing difficulties, including cessation of breathing for short periods of time. OSA effects both men and women but is amongst the commonest of chronic disorders of adult males, occurring in 5% of men over the age of 45 years. In the proposed studies we will examine the effect of the pressure in the tissues surrounding the throat on the ability of the throat to stay open a ....The obstructive sleep apnoea syndrome (OSA) refers to a condition in which throat blockage occurs during sleep leading to breathing difficulties, including cessation of breathing for short periods of time. OSA effects both men and women but is amongst the commonest of chronic disorders of adult males, occurring in 5% of men over the age of 45 years. In the proposed studies we will examine the effect of the pressure in the tissues surrounding the throat on the ability of the throat to stay open and allow breathing. The major outcome of the animal studies is increased knowledge concerning mechanisms whereby collapsing forces are applied to the upper airway. This will give insights into potential factors influencing upper airway collapse during sleep in OSA patients. Of particular importance will be our studies on the effects of jaw position on the pressure exerted on the walls of the throat since the use of an intra-oral device to hold the jaw forward during sleep is one of the treatments used to prevent throat blockage during sleep. The studies in humans will examine, for the first time, the notion that the mass (weight) of the neck has a direct effect on the severity of sleep disordered breathing. If neck mass has a substantive influence on sleep disordered breathing then strategies aimed at reducing neck mass (fat) may provide a new therapeutic approach to the management of OSA patients.Read moreRead less
The Impact Of CPAP Treatment On Carotid Artery Atherosclerosis In Heavy Snoring And Mild Sleep Disordered Breathing
Funder
National Health and Medical Research Council
Funding Amount
$697,512.00
Summary
Mild sleep disordered breathing, including habitual snoring, is a very common problem in the adult population, with a prevalence of between 20-40%. Increasingly it is now recognised that habitual snoring may be an independent risk factor for the development of stroke. In this proposal we will explore the hypothesis that treatment for snoring will slow or stop the development of carotid artery atherosclerosis.
Inhibition Of Fear Memories By Extinction: Neural Substrates.
Funder
National Health and Medical Research Council
Funding Amount
$234,250.00
Summary
Anxiety disorders [e.g., Post Traumatic Stress Disorder (PTSD)] are the most prevalent type of psychopathology in the industrialised world. They are associated with characteristic behavioural (e.g., heightened startle) and autonomic (e.g., cardiovascular) reactions. These disorders are often characterised as an inability to regulate the emotion of fear. Significant progress has been made in understanding the neural and cellular processes involved in the establishment of fear memories, but relati ....Anxiety disorders [e.g., Post Traumatic Stress Disorder (PTSD)] are the most prevalent type of psychopathology in the industrialised world. They are associated with characteristic behavioural (e.g., heightened startle) and autonomic (e.g., cardiovascular) reactions. These disorders are often characterised as an inability to regulate the emotion of fear. Significant progress has been made in understanding the neural and cellular processes involved in the establishment of fear memories, but relatively little is known about the mechanisms by which fear memories can be inhibited or suppressed. Understanding this latter process is a key to the development of effective treatments for anxiety disorders such as PTSD where the patient suffers from persistent, intrusive, unwanted trauma memories. A common experimental procedure for reducing learned fear is to repeatedly expose the subject to a fear-eliciting stimulus but without any aversive outcome. This procedure leads to a progressive loss, or extinction, of the fear reactions elicited by the stimulus. Historically, the extinction of fear was thought to be due to an erasure of the fear memory. However, recent evidence shows that extinction inhibits, rather than erases, the fear memory. Because the fear memories remain intact, some structure(s) in the brain must inhibit activity in the fear pathway. This project uses extinction of conditioned fear reactions in rat subjects to determine the structure(s) in the brain that inhibit fear memories and their behavioural and cardiovascular expression. It brings together the expertise of four well-established researchers and uses a combination of behavioural, physiological, immunohistochemical, tract tracing, and lesion approaches to achieve this aim. The proposed experiments will reveal the structure(s) in the brain that control the inhibition of fear, as well as the site(s) of this inhibition in the fear pathwayRead moreRead less