J. A. St John
Griffith University
Network
Latest external collaboration on country level. Dive into details by clicking on the dots.
Publication
Featured researches published by J. A. St John.
Neuroscience | 2016
J. Tello Velasquez; Lynnmaria Nazareth; Ronald J. Quinn; Jenny Ekberg; J. A. St John
Transplantation of peripheral glia is being trialled for neural repair therapies, and identification of compounds that enhance the activity of glia is therefore of therapeutic interest. We have previously shown that curcumin potently stimulates the activity of olfactory glia. We have now examined the effect of curcumin on Schwann cell (SC) activities including proliferation, migration and the expression of protein markers. SCs were treated with control media and with different concentrations of curcumin (0.02-20 μM). Cell proliferation was determined by MTS assay and migration changes were determined by single live cell migration tracking. We found that small doses of curcumin (40 nM) dramatically increased the proliferation and migration in SCs within just one day. When compared with olfactory glia, curcumin stimulated SC proliferation more rapidly and at lower concentrations. Curcumin significantly increased the migration of SCs, and also increased the dynamic activity of lamellipodial waves which are essential for SC migration. Expression of the activated form of the MAP kinase p38 (p-p38) was significantly decreased in curcumin-treated SCs. These results show that curcumins effects on SCs differ remarkably to its effects on olfactory glia, suggesting that subtypes of closely related glia can be differentially stimulated by curcumin. Overall these results demonstrate that the therapeutically beneficial activities of glia can be differentially enhanced by curcumin which could be used to improve outcomes of neural repair therapies.
Cell Transplantation | 2018
R. Yao; M. Murtaza; J. Tello Velasquez; Michael Todorovic; A. Rayfield; Jenny Ekberg; Matthew J. Barton; J. A. St John
Olfactory ensheathing cells (OECs) are glia reported to sustain the continuous axon extension and successful topographic targeting of the olfactory receptor neurons responsible for the sense of smell (olfaction). Due to this distinctive property, OECs have been trialed in human cell transplant therapies to assist in the repair of central nervous system injuries, particularly those of the spinal cord. Though many studies have reported neurological improvement, the therapy remains inconsistent and requires further improvement. Much of this variability stems from differing olfactory cell populations prior to transplantation into the injury site. While some studies have used purified cells, others have used unpurified transplants. Although both preparations have merits and faults, the latter increases the variability between transplants received by recipients. Without a robust purification procedure in OEC transplantation therapies, the full potential of OECs for spinal cord injury may not be realised.
Cell Transplantation | 2018
A. A. Wright; Michael Todorovic; J. Tello-Velasquez; A. Rayfield; J. A. St John; Jenny Ekberg
Autologous olfactory ensheathing cell (OEC) transplantation is a promising therapy for spinal cord injury; however, the efficacy varies between trials in both animals and humans. The main reason for this variability is that the purity and phenotype of the transplanted cells differs between studies. OECs are susceptible to modulation with neurotrophic factors, and thus, neurotrophins can be used to manipulate the transplanted cells into an optimal, consistent phenotype. OEC transplantation can be divided into 3 phases: (1) cell preparation, (2) cell administration, and (3) continuous support to the transplanted cells in situ. The ideal behaviour of OECs differs between these 3 phases; in the cell preparation phase, rapid cell expansion is desirable to decrease the time between damage and transplantation. In the cell administration phase, OEC survival and integration at the injury site, in particular migration into the glial scar, are the most critical factors, along with OEC-mediated phagocytosis of cellular debris. Finally, continuous support needs to be provided to the transplantation site to promote survival of both transplanted cells and endogenous cells within injury site and to promote long-term integration of the transplanted cells and angiogenesis. In this review, we define the 3 phases of OEC transplantation into the injured spinal cord and the optimal cell behaviors required for each phase. Optimising functional outcomes of OEC transplantation can be achieved by modulation of cell behaviours with neurotrophins. We identify the key growth factors that exhibit the strongest potential for optimizing the OEC phenotype required for each phase.
Ultrasound in Obstetrics & Gynecology | 2010
Ho Yin Wong; J. A. St John; Alan Mackay-Sim
just above the junction up to the renal pelvis with a diameter of 8.4 mm. 2D USG showed the renal calyceal dilatation (Figure 1), but the ureteral dilatation was difficult to identify because of the liquid containing image of the fetal intestines. With the aid of the 3D/4D USG view the insertion side of the right ureter in to the fetal urinary bladder was easily identified and measurement of the diameter done (Figure 1). Postnatal follow of the neonate showed no progression of the megaureter and hydroureteronephrosis.
Faculty of Health; Institute of Health and Biomedical Innovation | 2013
P. Panni; Ian A. Ferguson; Ifor R. Beacham; Alan Mackay-Sim; Jenny Ekberg; J. A. St John
Glia | 2017
J. Tello Velasquez; J. A. St John; Lynnmaria Nazareth; Jenny Ekberg
Faculty of Health | 2014
J. A. St John; Jenny Ekberg; Samantha J. Dando; Adrian Cuda Banda Meedeniya; Rachel Elizabeth Horton; Michael R. Batzloff; Suzzanne Owen; S. Holt; Ian R. Peak; Glen C. Ulett; Alan Mackay-Sim; Ifor R. Beacham
Glia | 2009
J. A. St John; Louisa Windus; Katie E. Lineburg; Susan Scott; Jenny Ekberg; E Hansen; Christina Claxton; Brian Key; Alan Mackay-Sim
Chemical Senses | 2006
Brian Key; J. A. St John
XXIIIrd Annual Meeting of the Association for Chemoreception Sciences | 2001
J. A. St John; Christina Claxton; Brian Key