A/Prof. Dirk Van Helden
|Work Phone||(02) 4921 5623|
|Fax||(02) 4921 7406|
Principal Research Fellow
School of Biomedical Sciences and Pharmacy
The University of Newcastle, Australia
|Office||MS405, Medical Sciences|
Investigations are being made on cellular rhythms including those in lymphatics, blood vessels, gastrointestinal tract, heart and specific mood-associated brain nuclei. We have discovered a new mechanism that it is driven by intracellular Ca2+ stores that allow groups of cells to self pace and hence become rhythmic. We are now exploring the relevance of this mechanism in a range of tissues. We are also interested in specific proteins involved in the pacemaker mechanism including inositol 1,4,5-trisphosphate receptors, ryanodine receptors, store operated calcium channels and TRP family proteins. These studies may influence future therapies to control lymphedema, digestive disorders, heart arrhythmias and brain mood states.
We also have a recent patent relating to use of a topical ointment as a first aid treatment against snakebite. This was a surprising outcome that arose from studies investigating whether snake venoms enhance lymphatic pumping and hence accelerate their own delivery. Our preliminary trials indicate topical application of the ointment slows lymphatic transport by some 350% with no obvious adverse effects. The cream will be of particular use for bites to the torso where pressure bandaging is ineffective. It may also be useful as a first aid treatment against bites from other venomous creatures.
- PhD, University of New South Wales
- Bachelor of Engineering, University of New South Wales
- Cellular physiologist
- gastrointestinal physiology
- heart pacemaking
- smooth muscle
Lymphatic and gastric pacemaking: Pacemaking in the lymphatic and gastric systems are the basis for our discovery of store pacemaking and calcium phase waves. We are now unravelling the finer details of these mechanisms. Importantly, as for all good research, there can often be unexpected yet important serendipitous outcomes. One in case is that this work has led to development of a first aid treatment against bites from venomous animals whose venoms transit the lymphatic system and we have a patent application on this finding under review.
Heart pacemaking: Traditionally, this has been considered to operate through a clock in the cell surface membrane of pacemaker cells. However, recent evidence from our pilot and modelling studies and from the work of others indicates a significant role of calcium stores. This introduces the possibility that the heart pacemaker model is only part of the story and that pacemaking involves an intracellular clock (i.e. store pacemaking). We are investigating this hypothesis, which if upheld will change the text book model for heart pacemaking and help change present understanding of specific heart disorders and their treatment.
(National Health and Medical Research Program Grant -NHMRC PG Cardiac Pacemaking, 2007-2009).
Brain rhythms: Brain rhythms function in most areas of the brain and while fundamental to life and our psyche remain poorly understood. We are testing the hypothesis that specific rhythms in the Locus Coeruleus, a brain stem nucleus known to be associated with mood states, are generated by store pacemaking. Evidence that the rhythms are generated by store pacemaking could provide a new framework for interpreting drug action in the treatment of mood disorders such as Bipolar Disorder, as all three main drug classes used in its treatment have the common mode action of inhibiting calcium stores.
(Australian Research Council Discovery Program Grant Investigation of a Brain Rhythm 2005-2007).
Uterine pacemaking: Astonishingly, there is still no clear understanding of the pacemaker mechanism that initiates and times uterine contractions. Pilot studies we have undertaken suggest this to be mediated by store pacemaking. Proof for this hypothesis would herald a mechanistic description for uterine contractions and may provide new insight into associated dysfunctions such as premature birth.
(NHMRC PG Rhythmicity and synchronicity in uterine smooth muscle, 2007-2009).
Fields of Research
|020599||Optical Physics Not Elsewhere Classified||50|
|110399||Clinical Sciences Not Elsewhere Classified||30|
|111699||Medical Physiology Not Elsewhere Classified||20|
Centres and Groups
Body relevant to professional practice.
- Faculty member - Cardiovascular Physiology/Circulation of 'Faculty of 1000 Biology'
- member of council - Australian Physiological society
- Chair, Research Committee - HMRI Cardiovascular Group
- Member of Editorial Board 2001-2005 - the British Journal of Pharmacology
- Member - The British Journal of Pharmacology
- member - Australian Physiological Society
|01/01/2001 - 01/12/2011|
NHMRC Senior Research Fellow
University of Newcastle (Australia)
|01/01/1990 - 01/12/2000|
Senior Brawn Fellowship
University of Newcastle (Australia)
Hunter Medical Research Institute (Australia)
2004 Hunter Medical Research Institute Sparke Helmore/ NBN Award for Research Excellence from a field of ~350 scientists in the University and Area Health Sectors
Gordon conference, United Kingdom (Conference Presentation - non published.)
Department of physiology
University of Western Australia, Australia (External Reviewer - Departments.)
Research policy (e.g. Archetect of the Brawn Fellowship Scheme at the University of Newcastle)
Honours and Postgraduate students
- Cellular Physiology