Jacqueline M. Ross

Our sense of hearing starts in the inner ear organ, the cochlea, which contains two types of auditory hair cells for signal transduction. Earlier research showed that the complex cochlear physiology is regulated in part by purinergic signalling through activation of purine-mediated P2X, P2Y and adenosine receptors expressed in the cochlea. This study aims to extend our knowledge of purinergic signalling in the cochlea by comprehensively characterising the expression of the P2X4 receptor subtype. Wistar rat cochlea (embryonic day 20.5–6 weeks, both sexes) were collected, and the P2X4 expression was examined by immunohistochemistry. Robust P2X4 expression was found in the organ of Corti (OoC) in the inner hair cells (IHCs) and outer hair cells (OHCs), confirmed by double-labelling with hair cells (HCs) marker myosin VIIa. In IHCs, a robust cytoplasmic P2X4 expression occurred throughout the cell body, with the most intense signal at the medial side. In OHCs, P2X4 formed puncta near the apical and basal ends of the cell body. Using markers for subcellular organelles, P2X4 immunoreactivity was predominately associated with the trans-Golgi network apparatus and early endosomes in IHC and with early endosomes and lysosomes in OHC in the mature cochlea. In both cell types, some co-localisation of P2X4 with presynaptic marker was also observed. Taken together, these observations suggest unique roles for P2X4 in mature IHCs and OHCs as a purinergic receptor subtype responsible for the homeostatic regulation of hair cells and auditory sensory transduction.

With the emergence of deadly viral and bacterial infections, preventing the spread of microorganisms on surfaces has gained ever-increasing importance. This study investigates the potential of solid-state supercapacitors as antibacterial and antiviral devices. We developed a low-cost and flexible carbon cloth supercapacitor (CCSC) with highly efficient antibacterial and antiviral surface properties. The CCSC comprised two parallel layers of carbon cloth (CC) electrodes assembled in a symmetric, electrical double-layer supercapacitor structure that can be charged at low potentials between 1 to 2 V. The optimized CCSC exhibited a capacitance of 4.15 ± 0.3 mF cm⁻² at a scan rate of 100 mV s⁻¹, high-rate capability (83% retention of capacitance at 100 mV s⁻¹ compared to its value at 5 mV s⁻¹), and excellent electrochemical stability (97% retention of the initial capacitance after 1000 cycles). Moreover, the CCSC demonstrated outstanding flexibility and retained its full capacitance even when bent at high angles, making it suitable for wearable or flexible devices. Using its stored electrical charge, the charged CCSC disinfects bacteria effectively and neutralizes viruses upon surface contact with the positive and negative electrodes. The charged CCSC device yielded a 6-log CFU reduction of Escherichia coli bacterial inocula and a 5-log PFU reduction of HSV-1 herpes virus. Antibacterial and antiviral carbon cloth supercapacitors represent a promising platform technology for various applications, including electronic textiles and electronic skins, health monitoring or motion sensors, wound dressings, personal protective equipment (e.g., masks) and air filtration systems.

In this work, we demonstrate that t-tubule remodeling occurs in the atrophied left ventricle as well as the overloaded right ventricle after right-side heart failure. Moreover, we identify that t-tubule remodeling in both ventricles is linked to sarcoplasmic reticulum remodeling as indicated by decreased labeling periodicity of both the Ca²⁺ release channel, RyR2, and the cardiac junction-forming protein, JPH2, that forms a link between the sarcoplasmic reticulum and sarcolemma. Studies developing treatments for right-sided heart failure should consider effects on both the right and left ventricle.

Knowledge of optical properties, such as the refractive index (RI), of biological tissues is important in optical imaging, as they influence the distribution and propagation of light in tissue. To accurately study the response of cancerous cells to drugs, optimised imaging protocols are required. This study uses a simple custom-built spectral domain optical coherence tomography (OCT) system to conduct RI measurements of multicellular spheroids, three-dimensional (3D) in-vitro culture systems, of the cell line HCT116. The spheroid RIs are compared to study the effect of growth over time. To improve confocal microscopy imaging protocols, two immersion media (glycerol and ScaleView-A2) matching the spheroid RIs were trialled, with the aim to reduce the RI mismatch between the spheroid and the immersion medium and thus improve imaging depth with confocal microscopy. ScaleView-A2 (n = 1.380) aided in achieving greater depths of imaging of the multicellular spheroids under confocal microscopy. This improvement in imaging depth confirmed the utility of our RI measurements, proving the promising outlook of OCT as a complementary tool to microscopy in cancer research.

Today’s students have increased expectations for flexible learning options and evidence-based practice resources to be available to support curricular activities. We investigated: (i) the suitability of a static website for teaching ocular anatomy and physiology and an interactive version of the website with quiz and self-assessment activities and (ii) the usefulness of a blended online and in-lab environment to teach in Optometry. We administered a survey to compare responses of optometry students who had access to the interactive website, with those from students from a previous year who used the static version. We examined learning preferences of students in a focus group. Students were positive about the value of the website for their learning and the clarity of the website content. Nevertheless, objective comparison of pass rates for students using the static and interactive websites did not show significant changes. The majority of students commenting on the static website felt they did not get sufficient feedback via the website (67%) compared with only 22% from students who used self-assessments in the interactive website. Interestingly, users of the static website commented that it was perceived as just another resource while users of the interactive website commented on the usefulness of the material to review knowledge before laboratories. In the focus group, students reported they preferred a blended learning over the website alone even by students using the interactive website as they felt the need to revise content with the educator before the test. We conclude that there is acceptance of online learning methods due to the technologically ‘savvy’ environment of students in the first year of the Optometry programme but there is still dependence on the educator as the main administrator of their learning.

ASA404, a Tumor-Vascular Disrupting Agent developed at the Auckland Cancer Society Research Centre, is currently undergoing two Phase III clinical trials (Novartis) against non-small cell lung cancer. Its early effects on tumor tissue include increased tumor vascular permeability, increased tumor endothelial apoptosis, decreased tumor blood flow and increased tumor hypoxia. The basis for the selective effect of ASA404 on tumor versus normal vasculature is not clear. We hypothesized that VEGF, produced in tumor tissue in responses to hypoxia and other stresses, played a possible role in this selectivity. We compared the actions of ASA404 and VEGF in vitro and also examined the potential for induction of tumor VEGF by ASA404 treatment in vivo. We grew human umbilical vein endothelial cells (HUVEC) on Matrigel and compared in vitro responses to ASA404 and human VEGF using time-lapse microscopy and image analysis. Both ASA404 (30 and 300 µM; 9.9 and 99 µg/ml) and VEGF (50 ng/ml) stimulated the initial formation of 2-dimensional tubular networks on Matrigel. Both ASA404 and VEGF induced actin stress fiber formation in cultured HUVEC's, consistent with increased migration. To determine if there was an in vivo relationship between ASA404 and VEGF expression, mice with Rif-1 tumors (7-9 mm diameter) were treated i.p. with ASA404 (70 µmol/kg; 21 mg/kg) and mRNA was extracted from tumor tissue 4 hours later. VEGF-A mRNA abundance was measured by co-amplification with endogenous 18S mRNA as standard. VEGF-A relative abundance rose from 0.6 ± 0.1 to 1.3 ± 0.1 (p < 0.01). VEGF-B and VEGF-D concentrations also increased but the changes were not significant. The results are consistent with the following model: hypoxia and other stresses in tumor tissue lead to synthesis by both tumor and host cells of VEGF, which increases vascular permeability and partially compromises tumor blood flow. The administration of ASA404 leads to increased tumor vascular permeability and vascular endothelial apoptosis, possibly by a pathway involving p38 kinase, ceramide synthesis and actin stress fiber formation. The resultant decrease in tumor blood flow further increases hypoxia, potentially providing a positive feedback loop by stimulating further VEGF production. These effects, in combination with other cytokines such as tumor necrosis factor that are induced by ASA404, lead to tumor vascular failure. Thus, endogenous VEGF production by tumor tissue may contribute to the antitumor selectivity of ASA404. Further studies addressing the modulatory role of VEGF in the action of ASA404 are warranted. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 1660.

The aim of this study was to assess whether enzymatically isolated chondrons from normal adult articular cartilage could be used as a model for the onset of osteoarthritis, by comparison with mechanically extracted chondrons from osteoarthritic cartilage. Enzymatically isolated chondrons (EC) were cultured for 4 weeks in alginate beads and agarose gel constructs. Samples were collected at days 1 and 2, and weekly thereafter. Samples were immunolabelled for types II and VI collagen, keratan sulphate and fibronectin and imaged using confocal microscopy. Mechanically extracted chondrons (MC) were isolated, immunohistochemically stained for type VI collagen and examined by confocal microscopy. In culture, EC showed the following characteristics: swelling of the chondron capsule, cell division within the capsule and remodelling of the pericellular microenvironment. This was followed by chondrocyte migration through gaps in the chondron capsule. Four types of cell clusters formed over time in both alginate beads and agarose constructs. Cells within clusters exhibited quite distinct morphologies and also differed in their patterns of matrix deposition. These differences in behaviour may be due to the origin of the chondrocytes in the intact tissue. The behaviour of EC in culture paralleled the range of morphologies observed in MC, which presented as single and double chondrons and large chondron clusters. This preliminary study indicates that EC in culture share similar structural characteristics with MC isolated from osteoarthritic cartilage, confirming that some processes that occur in osteoarthritis, such as pericellular remodelling, take place in EC cultures. The study of EC in culture may therefore provide an additional tool to investigate the mechanisms operating during the initial stages of osteoarthritis. Further investigation of specific osteoarthritic phenotype markers will, however, be required in order to validate the value of this model.