https://nova.newcastle.edu.au/vital/access/ /manager/Index en-au 5 https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:14560 Sat 24 Mar 2018 08:24:55 AEDT ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:14479 Sat 24 Mar 2018 08:18:51 AEDT ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:14546 Sat 24 Mar 2018 08:18:49 AEDT ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:16516 A receptor, and that has anti-apoptotic and anti-excitotoxic actions, reducing brain damage in adult animal models of brain injury. We sought to determine if prophylactic treatment of the pregnant female with a single dose of this steroid could reduce birth asphyxia-induced losses in hippocampal function at 5 days of age (P5) in spiny mouse neonates (Acomys cahirinus). At 37 days gestation (term = 39 days) and 1 h before inducing birth asphyxia, spiny mice dams were injected subcutaneously (0.2 ml) with either 3 mg/kg allopregnanolone or 20% w/v β-cyclodextrin vehicle. One hour later, fetuses were either delivered immediately by caesarean section (control group) or exposed to 7.5 min of in utero asphyxia, causing acidosis and hypoxia. At P5, ex vivo hippocampal plasticity was assessed, or brains collected to determine cell proliferation (proliferating cell nuclear antigen; PCNA) or calcium channel expression (inositol trisphosphate receptor type 1; IP₃R1) using immunohistochemistry. Allopregnanolone partially prevented the decrease in long term potentiation at P5, and the asphyxia-induced increase in IP₃R1 expression in CA1 pyramidal neurons. There was no effect of allopregnanolone on the asphyxia induced impairment of the input/output (I/O) curve and paired-pulse facilitation (PPF). In control birth pups, maternal allopregnanolone treatment caused significant changes in short term post-synaptic plasticity and also reduced hippocampal proliferation at P5. These findings show that allopregnanolone can modulate hippocampal development and synaptic function in a normoxic or hypoxic environment, possibly by modifying calcium metabolism. Best practice for treatment dose and timing of treatment will need to be carefully considered.]]> Sat 24 Mar 2018 08:01:15 AEDT ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:28296 Pseudonaja spp.)-induced early cardiovascular collapse is a life-threatening medical emergency in Australia. We have previously shown that this effect can be mimicked in animals and is mediated via the release of endogenous mediators. In the present study, we aimed to purify and characterize the component in Pseudonaja textilis venom which induces cardiovascular collapse following envenoming. The component (fraction 3) was isolated using a combination of techniques including hydroxyapatite and reverse phase chromatography. Fraction 3 (10 or 20 µg/kg, i.v.) produced a rapid decrease in mean arterial pressure (MAP) followed by cardiovascular collapse. Fraction 3-induced early collapse was abolished by prior administration of smaller priming doses of fraction 3 (i.e. 2 and 5 µg/kg, i.v.) or heparin (300 units/kg, i.v.). P. textilis whole venom (1 and 3 µg/ml), but not fraction 3 (1 or 3 µg/ml), induced endothelium-dependent relaxation in isolated rat mesenteric arteries. SDS-PAGE gel indicated the presence of 9-10 protein bands of fraction 3. Using proteomic based analysis some protein bands of fraction 3 were identified as subunits of venom prothrombin activator, pseutarin C of P. textilis venom. Our results conclude that prothrombin activator-like toxin is likely to be a contributor to the rapid collapse induced by P. textilis venom.]]> Sat 24 Mar 2018 07:33:50 AEDT ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:21234 Mon 23 Sep 2019 13:08:04 AEST ]]>