Batch Tests for Optimisation of Solvent Composition and Process Flexibility of the CHALMEX FS-13 Process

Studies have been performed with the purpose of determining the optimal solvent composition of a Chalmers grouped actinide extraction (CHALMEX) solvent for the selective co-extraction of transuranic elements in a novel Grouped ActiNide EXtraction (GANEX) process. The solvent is composed of 6,6’-bis(5,5,8,8-tetramethyl-5,6,7,8-tetrahydro-benzo-[1,2,4]-triazin-3-yl)-[2,2’]-bipyridine (CyMe4-BTBP) and tri-n-butyl phosphate (TBP) in phenyl trifluoromethyl sulfone (FS-13). The performance of the system has been shown to significantly depend on the ratios of the two extracting agents and the diluent to one another. Furthermore, the performance of the determined optimal solvent (10\ua0mM CyMe4-BTBP in 30% v/v TBP and 70% v/v FS-13) on various simulated PUREX raffinate solutions was tested. It was found that the solvent extracts all transuranic elements with high efficiency and good selectivity with regard to most other elements (fission products/activation products) present in the simulated PUREX raffinate solutions. Moreover, the solvent was found to extract a significant amount of acid. Palladium, silver, and cadmium were co-extracted along with the TRU-radionuclides, which has also been observed in other similar CHALMEX systems. The extraction of plutonium and uranium was preserved for all tested simulated PUREX raffinate solutions compared to experiments using trace amounts

Generation of three-dimensional multiple spheroid model of olfactory ensheathing cells using floating liquid marbles

We describe a novel protocol for three-dimensional culturing of olfactory ensheathing cells (OECs), which can be used to understand how OECs interact with other cells in three dimensions. Transplantation of OECs is being trialled for repair of the paralysed spinal cord, with promising but variable results and thus the therapy needs improving. To date, studies of OEC behaviour in a multicellular environment have been hampered by the lack of suitable three-dimensional cell culture models. Here, we exploit the floating liquid marble, a liquid droplet coated with hydrophobic powder and placed on a liquid bath. The presence of the liquid bath increases the humidity and minimises the effect of evaporation. Floating liquid marbles allow the OECs to freely associate and interact to produce OEC spheroids with uniform shapes and sizes. In contrast, a sessile liquid marble on a solid surface suffers from evaporation and the cells aggregate with irregular shapes. We used floating liquid marbles to co-culture OECs with Schwann cells and astrocytes which formed natural structures without the confines of gels or bounding layers. This protocol can be used to determine how OECs and other cell types associate and interact while forming complex cell structuresJSJ was funded by a grant from the Perry Cross Spinal Research Foundation; NTN was funded from Griffith University through a start-up grant and a grant from the Griffith University Research Infrastructure Program; JAK was funded by an Australian Research Council Discovery Grant DP150104495; JT was funded by an Eskitis Institute scholarship; CO was funded by a Griffith Sciences scholarship; RV was funded by a Griffith University International Postgraduate Research Scholarshi

Streptococcus agalactiae infects glial cells and invades the central nervous system via the olfactory and trigeminal nerves

Streptococcus agalactiae causes neonatal meningitis and can also infect the adult central nervous system (CNS). S. agalactiae can cross the blood-brain barrier but may also reach the CNS via other paths. Several species of bacteria can directly invade the CNS via the olfactory and trigeminal nerves, which extend between the nasal cavity and brain and injury to the nasal epithelium can increase the risk/severity of infection. Preterm birth is associated with increased risk of S. agalactiae infection and with nasogastric tube feeding. The tubes, also used in adults, can cause nasal injuries and may be contaminated with bacteria, including S. agalactiae. We here investigated whether S. agalactiae could invade the CNS after intranasal inoculation in mice. S. agalactiae rapidly infected the olfactory nerve and brain. Methimazole-mediated model of nasal epithelial injury led to increased bacterial load in these tissues, as well as trigeminal nerve infection. S. agalactiae infected and survived intracellularly in cultured olfactory/trigeminal nerve- and brain-derived glia, resulting in cytokine production, with some differences between glial types. Furthermore, a non-capsulated S. agalactiae was used to understand the role of capsule on glial cells interaction. Interestingly, we found that the S. agalactiae capsule significantly altered cytokine and chemokine responses and affected intracellular survival in trigeminal glia. In summary, this study shows that S. agalactiae can infect the CNS via the nose-to-brain path with increased load after epithelial injury, and that the bacteria can survive in glia

Isolation and Structure-Activity of -Conotoxin TIIIA, A Potent Inhibitor of Tetrodotoxin-Sensitive Voltage-Gated Sodium Channels

ABSTRACT -Conotoxins are three-loop peptides produced by cone snails to inhibit voltage-gated sodium channels during prey capture. Using polymerase chain reaction techniques, we identified a gene sequence from the venom duct of Conus tulipa encoding a new -conotoxin-TIIIA (TIIIA). A 125 I-TIIIA binding assay was established to isolate native TIIIA from the crude venom of Conus striatus. The isolated peptide had three post-translational modifications, including two hydroxyproline residues and C-terminal amidation, and Ͻ35% homology to other -conotoxins. TIIIA potently displaced [ 3 H]saxitoxin and 125 I-TIIIA from rat brain (Na v 1.2) and skeletal muscle (Na v 1.4) membranes. Alanine and glutamine scans of TIIIA revealed several residues, including Arg14, that were critical for high-affinity binding to tetrodotoxin (TTX)-sensitive Na ϩ channels. We were surprised to find that [E15A]TIIIA had a 10-fold higher affinity than TIIIA for TTX-sensitive sodium channels (IC 50 , 15 vs. 148 pM at rat brain membrane). TIIIA was selective for Na v 1.2 and -1.4 over Na v 1.3, -1.5, -1.7, and -1.8 expressed in Xenopus laevis oocytes and had no effect on rat dorsal root ganglion neuron Na ϩ current

Olfactory ensheathing cells for spinal cord repair: crucial differences between subpopulations of the glia

Griffith Sciences, Griffith Institute for Drug DiscoveryFull Tex

Advances in Electrospun Nerve Guidance Conduits for Engineering Neural Regeneration

Injuries to the peripheral nervous system result in devastating consequences with loss of motor and sensory function and lifelong impairments. Current treatments have largely relied on surgical procedures, including nerve autografts to repair damaged nerves. Despite improvements to the surgical procedures over the years, the clinical success of nerve autografts is limited by fundamental issues, such as low functionality and mismatching between the damaged and donor nerves. While peripheral nerves can regenerate to some extent, the resultant outcomes are often disappointing, particularly for serious injuries, and the ongoing loss of function due to poor nerve regeneration is a serious public health problem worldwide. Thus, a successful therapeutic modality to bring functional recovery is urgently needed. With advances in three-dimensional cell culturing, nerve guidance conduits (NGCs) have emerged as a promising strategy for improving functional outcomes. Therefore, they offer a potential therapeutic alternative to nerve autografts. NGCs are tubular biostructures to bridge nerve injury sites via orienting axonal growth in an organized fashion as well as supplying a supportively appropriate microenvironment. Comprehensive NGC creation requires fundamental considerations of various aspects, including structure design, extracellular matrix components and cell composition. With these considerations, the production of an NGC that mimics the endogenous extracellular matrix structure can enhance neuron–NGC interactions and thereby promote regeneration and restoration of function in the target area. The use of electrospun fibrous substrates has a high potential to replicate the native extracellular matrix structure. With recent advances in electrospinning, it is now possible to generate numerous different biomimetic features within the NGCs. This review explores the use of electrospinning for the regeneration of the nervous system and discusses the main requirements, challenges and advances in developing and applying the electrospun NGC in the clinical practice of nerve injuries

CIC-5: A chloride channel with multiple roles in renal tubular albumin uptake

CIC-5 is a chloride (Cl-) channel expressed in renal tubules and is critical for normal tubular function. Loss of function nonsense or missense mutations in CIC-5 are associated with Dent's disease, a condition in which patients present with low molecular weight (LMW) proteinuria (including albuminuria), hypercalciuria and nephrolithiasis. Several key studies in CIC-5 knockout mice have shown that the proteinuria results from defective tubular reabsorption of proteins. CIC-5 is typically regarded as an intracellular Cl- channel and thus the defect in this receptor-mediated uptake pathway was initially attributed to the failure of the early endosomes to acidify correctly. CIC-5 was postulated to play a key role in transporting the Cl- ions required to compensate for the movement of H+ during endosomal acidification. However, more recent studies suggest additional roles for CIC-5 in the endocytosis of albumin. CIC-5 is now known to be expressed at low levels at the cell surface and appears to be a key component in the assembly of the macromolecular complex involved in protein endocytosis. Furthermore, mutations in CIC-5 affect the trafficking of v-H+-ATPase and result in decreased expression of the albumin receptor megalin/cubulin. Thus, the expression of CIC-5 at the cell surface as well as its presence in endosomes appears to be essential for normal protein uptake by the renal proximal tubule. (c) 2005 Elsevier Ltd. All rights reserved

The effect of VEGF and PDGF growth factors in olfactory regeneration

Background The olfactory system has a unique ability to regenerate throughout life. The nerve cells that detect odours are directly exposed to bacteria, viruses and toxic chemicals which cause an estimated 1-3% of nerve cells dying each day. Luckily stem cells that residue in the olfactory epithelium within the nasal cavity produce new olfactory neurons which send long fibres up through the cribriform plate of the ethmoid bone and terminate within the olfactory bulb to make new connections. However, when extensive damage to the olfactory nerve occurs such as skull base surgery, regenerating olfactory axons cannot find their targets and are unable to make functional connections to the olfactory bulb which causes anosmia. This is due to axonal mis-targeting in the forebrain or scar tissue formations which make a physical barrier and prevent axons reach the target tissue. Loss of smell (anosmia) can be devastating for patients. Smell dysfunction significantly influences physical wellbeing, quality of life, nutritional status as well as everyday safety and is associated with increased mortality. Currently there is no effective treatment to restore olfaction (sense of smell). One of the major causes of anosmia is skull base surgery which uses the intranasal transsphenoidal approach to remove tumors. Despite care to minimise damage to the olfactory region during surgery, patients can suffer permanent reduction or complete loss of olfaction. It has been shown that anosmia can reduce life-expectancy of individuals by up to 5 years. Therefore, there is a need to find a treatment for anosmia

Significant improvement of the olfactory regeneration by the VEGF and PDGF growth factors treatment

Anosmia due to large-scale olfactory nerve damage from skull base surgery is an important problem for human health that significantly influences physical wellbeing, quality of life, and life-expectancy in those affected. Therefore, there is a need to find a treatment for anosmia. The VEGF and PDGF growth factor treatments have improved regeneration of the CNS after injury. Therefore, we have tested the roles of the combined growth factors in improvement of olfactory regeneration in mice. The degeneration of the murine olfactory neurons was induced by unilateral surgical removal of the olfactory bulb. The animals were randomly divided into two groups: the treatment animals group received 0.5 μg of the combined growth factors and the control animals received PBS. Combined growth factor and PBS was intranasally administered over three days, and tissues were harvested from the two groups at different time points post-surgery and histological techniques were used for analysis. We have found that olfactory regenerating axons projected significantly deeper to the brain in the treatment group compared to the control group at day 10 and 14 (p < 0.05) and the thickness of the olfactory epithelium was significantly increased after 10 days post- surgery in the treatment group (p < 0.05). The results indicate that the combined delivery of VEGF and PDGF growth factor treatments has improved regeneration of olfactory neurons in this murine model and has the potential to restore the sense of smell in humans with anosmia

Combined VEGF/PDGF improves olfactory regeneration after unilateral bulbectomy in mice

The olfactory receptor neurons lining the nasal cavity have a remarkable capacity to regenerate throughout life. They are replenished continuously and their axons make new connections within the olfactory bulb. However, some factors such as head trauma and skull base surgery damage the olfactory nerve which lead to olfactory dysfunction. Losing the sense of smell has considerable effects on quality of life and life-expectancy. Therefore, there is a clear need to find a treatment for olfactory dysfunction. One such potential treatment is growth factor therapy which showed promising results in the spinal cord and brain injuries. The aim of the present study was to investigate whether combined delivery of two growth factors, vascular endothelial growth factor and platelet-derived growth factor treatment can improve the olfactory neurons regeneration in mice. The degeneration of the olfactory neurons was induced by unilateral bulbectomy. The treatment group received 1.5 µg of the combined growth factors intranasally, while the control injured group received saline. Growth factor treatment significantly increased the number of immature neurons at 5 and 7 days post injury and also the number of mature olfactory neurons at 10 and 14 days post bulbectomy. Regenerating axons extended over a larger volume in the operated cavity in the treatment group compared to control group at 14 days post bulbectomy. The growth factor treatment also significantly reduced astrocytic glia scar in the operated cavity. The results indicate that the combined delivery of the growth factors has the potential to improve olfactory dysfunction