email: t.bjorkman@uq.edu.au

Research Interests

A lack of oxygen (hypoxia) and poor blood supply (ischemia) at the time of birth is a significant cause of neonatal death and long-term neurodevelopmental disability. Babies who survive a hypoxic/ischemic (HI) insult are at increased risk of seizures and cerebral palsy leading to lifelong neurological deficits affecting cognitive, learning and motor abilities. Present strategies for detection and treatment of HI and seizures in the neonate are extremely inadequate.

Dr Tracey Björkman is a Lions Senior Medical Research Fellow studying hypoxic brain injury in the newborn.

Dr Björkman's research interests include GABA and glutamate neurotransmission, and excitotoxic mechanisms of cell injury in the neonatal brain. An understanding of normal brain development and the pathways through which brain injury occurs will allow more appropriate neuroprotective therapies to be implemented, thus minimising hypoxic-ischemic brain damage and reducing long-term disability.

Dr Björkman's research interests are:

• Perinatal GABA_A receptor development
• GABA mediated excitotoxicity in immature brain
• Seizures and injury following hypoxia
• Neuroprotective therapies for newborn hypoxic brain

Research Projects

Results from our previous research suggest that seizures are associated with a much greater degree of brain damage following a hypoxic/ischemic (HI) insult than HI damage alone. Given that over 50% of seizures in neonates are 'silent' this may be of major consequence; the dependence on clinical signs of seizure in the neonatal ICU means that there is an enormous risk for 'silent' seizures to go undetected and therefore untreated in more than half of term HI babies.

However despite widespread clinical use, anticonvulsant drugs do not effectively treat seizures in the newborn brain. In adults anticonvulsants activate brain receptors and decrease brain activity, however in neonates the same anticonvulsants may increase brain activity potentially worsening seizures and HI brain damage. My current research focus is to understand the intrinsic differences in neonatal brain receptors. This will underpin future studies to develop new treatments to protect the newborn brain.

Key publications

V.P. Kalanjati, S.M. Miller, Z. Ireland, P.B. Colditz, S.T. Bjorkman (2011) Developmental expression and distribution of the GABA_A receptor a₁, a₃ and b₂ subunits in perinatal pig brain. Dev Neurosci May 25 DOI: 10.1159/000326630

S.T. Bjorkman, S.M. Miller, S.E. Rose, C Burke, P.B. Colditz (2010) Seizures are associated with brain injury severity in a neonatal hypoxia-ischemia model. Neuroscience 161(1):157-67.

Bjorkman ST, Foster KA, O'Driscoll SM, Healy GN, Lingwood BE, Burke C, Colditz PB. (2006) Hypoxic/Ischemic models in newborn piglet: comparison of constant FiO₂ versus variable FiO₂ delivery. Brain Res. 1100: 110-117.

Contact details and email

Dr Tracey Bjorkman BSc PhD

Perinatal Research Centre

UQ Centre for Clinical Research

RBWH, Herston Q 4029

t.bjorkman@uq.edu.au

Ph 61+7+3346 6015

Fax 61+7+3346 5594

Funding acknowledgement

NHMRC

UQECR

Lions Medical Research Foundation

Technique Expertise

Neonatal HI animal models

Protein expression

Molecular biology techniques

Research Staff

Ms Stephanie Miller BSc (Hons)

Senior Research Assistant

Dr Xiyong Fan MD PhD

Research Officer

Mr Nick Ward BSc (Hons)

Research Assistant

Collaborations

Dr Cacha Peeters-Scholte (Neurophyxia B.V., Netherlands)

Mr Paul Leufkens (Neurophyxia B.V., Netherlands)

Dr Rod Hunt (RCH, Melbourne)

Dr Tim Donovan (RBWH, Brisbane)

Dr Geraldine Boylan (Ireland)

Dr Peter Dodd (SCMS, UQ)

Prof Seong-Seng Tan (Howard Florey Institute, Melbourne)

Key Words

Medical: Receptors, Medical: Perinatal Disorders, Medical: Neuropathology, Medical: Ion Channels, Medical: Injury, Medical: Anticonvulsants, Medical: Neonatal Disorders, Medical: Neurotransmitters, Medical: Brain, Medical: Animal Model, Medical: Perinatal Health