The OMRF funds 20 summer research projects related to human health, including biomedical sciences and public health.
The timing and strength of heart contraction is dependent on handling of calcium (Ca2+) within cardiac muscle cells. Critical to this process is the ryanodine receptor (RyR2), which is responsible for mediating Ca2+ release from the sarcoplasmic reticulum into the cytosol of the cell. Numerous protein kinases have been shown to phosphorylate RyR2, however few have had this correlated with altered RyR2 activity. By utilising Ca2+ imaging in combination with RyR2 mutagenesis and pharmacological validation, this study aims to determine the role of the stress-induced kinase, protein kinase G, as a novel regulator of RyR2 and, therefore, cardiac Ca2+ -handling.
The rising prevalence of diabetes has made it an epidemic in the developing world. Diabetic cardiomyopathy (DCM), a common form of heart disease in diabetics, is a long-term complication of diabetes which remains asymptomatic until considerable structural and functional damage has occurred. MicroRNAs are small, highly-conserved genetic molecules involved in the pathophysiological process of DCM and it is thought that the specific patterns of these molecules may indicate the development of this disease. This project attempts to show that changes in the circulating levels of cardio-specific microRNAs can be used to detect DCM in its initial stages allowing for early intervention.
As microbes speed ahead, evolving resistance to all known clinical antibiotics, new drug development lags behind, and our hopes to gain a leg in the ‘antibiotic arms race’ diminish. Fortunately, recent research suggests that evolution of resistance comes with an exploitable underlying vulnerability: resistance against one antibiotic provokes increased sensitivity to others. Known as collateral hypersensitivity, this project aims to explore this phenomenon. High-throughput techniques will be used to study resistance development while, in parallel, systematically assess the collateral hypersensitivity profile in two bacterial species. Ultimately, this hints at new strategies to combat antibiotic resistance, without demanding novel drug design.
The mammalian and human visual system processes complex visual information in a ventral pathway, terminating in the inferior temporal cortex. A network of inferior temporal cortex cells fire specifically to faces, allowing individual recognition. The avian visual system processes complex visual information in an analogous pathway, terminating in the nidopallium frontolaterale (NFL). Very little is known about the NFL, but recent investigation suggests it is functionally comparable to the inferior temporal cortex. The aim of the present experiment is to investigate the response properties of cells in the NFL to faces, to develop a non-primate animal model for disorders of facial recognition.
Title: Investigation into the role of cell microtubules and proteins in Listeria infections in humans
An investigation into the role of human cell microtubules and proteins in Listeria monocytogenes infections will be carried out. Listeria entry is mediated by interaction of the bacterial surface protein InlB with the human receptor Met. Entry of Listeria is known to require bacterial manipulation of the host actin cytoskeleton. However, the role of the host microtubule cytoskeleton in Listeria infection remains poorly understood. Importantly, entry of Listeria is known to require an intact microtubule cytoskeleton and several host proteins that associate with microtubules, including LL5α, LL5β, and CLASP2. The aims of this project are to (1) determine whether microtubules mediate the translocation of LL5α and LL5β proteins to areas of the plasma membrane contacting InlB-coated beads and (2) examine the role of host protein CLASP2 in translocation of the LL5 proteins.
REES GUISE (Dr Fiona Doolan-Noble, Professor Tim Stokes and Mr Kyle Forde, Department of General Practice and Rural Health, Dunedin School of Medicine)
Title: Do adults with intellectual disabilities receive less preventative care compared to those who do not have intellectual disabilities in primary care?
For people with intellectual disabilities (ID), disparities in unmet health care need and poorer health outcomes is a significant issue in New Zealand, recognising that Otago and Māori have higher rates of ID. Further research into this area would meet the goals of the New Zealand Disability Strategy 2016-2026, the United Nations Convention on the Rights of Persons with Disabilities, and the Vision Mātauranga: Hauora/Oranga Improving Health and Social Wellbeing. This research aims to increase understanding of both differences in preventative care, as well as utilisation of primary health care between people with and without ID in the Southern region.
Human papillomavirus (HPV) is a well-known cause of cervical cancer. Mechanisms involved in the progression from low grade premalignant lesions to high grade lesions and cancer have been widely studied. Progression to an invasive cancer is likely contributed to by virus-mediated immune evasion, in part due to a reduced ability to detect viral antigens, and in part due to functions of the HPV oncoprotein E7. This study will explore the regulatory effects of E7 protein on incorporation of cellular protein into microparticles shed from E7 expressing cells and will further determine the efficacy of the drug Y-27632 in suppression of microparticle shedding from E7 expressing cells.
Moa Bone® (MB) is a bovine bone product that has been found by this group to induce clinically important bone growth when used as a graft material. It thus has the potential to enhance jaw bone growth following disease or tooth extraction. A challenge associated with using MB is minimising infections and we are therefore investigating an antimicrobial coating comprised of nanosilver. This research will investigate the safety of nanosilver using in vitro live and dead cell assays with primary human gum-derived fibroblast. This will provide information on the suitability of nanosilver for delivery as an antimicrobial coating for MB.
CAMERON KEELTY (Dr Bill Hawkins, Department of Chemistry, Division of Sciences, and Professor Parry Guilford, Department of Biochemistry, School of Biomedical Sciences)
The E-cadherin protein acts as a tumour suppressant, the down regulation of which has been associated with the formation of metastatic cancers. The treatment options for these cancers are currently limited. Work by Professor Parry Guildford’s research group has identified several compounds via a high throughput screen that selectively target E-cadherin deficient tumour cells. The exact mechanism of action of these compounds is unknown and may be probed by the identification of structure-activity relationships (SARs), characterisation of target molecules (by protein screens) and computational analysis. This will provide information about cellular receptors and allow for the identification of potential drug candidates.
Candida albicans, a human commensal microorganism, is the most frequent cause of oral fungal infections that can become life-threatening invasive infections in the immunocompromised. Azole antifungals are the first line of defence to treat candidiasis. However, azole resistance due to the overexpression of the C. albicans multidrug efflux pump Cdr1 can seriously impair treatment outcome. Six conserved cysteines within the extracellular domain of Cdr1 are predicted to stabilise its structure by forming three disulphide bonds. This project will create and over-express four Cdr1 variants in Saccharomyces cerevisiae and use mass spectrometry to determine which cysteine pairs form three disulphide bonds.
VALERY LIU (Associate Professor Fiona McDonald, Department of Physiology, School of Biomedical Sciences)
Epithelial Na+ channels (ENaC) maintain fluid and electrolyte balance by regulating Na+ transport. To control Na+ transport, the density of ENaC membrane expression may be controlled. The retromer protein complex regulates endosome recycling of ENaC. SNX proteins (components of the retromer) contribute to formation of endosomal membrane tubules and packaging of ENaC into those tubules for recycling back to the cell surface. This research aims to identify the function of SNX17 on Na+ transport thus shedding light on its role in the retromer complex. This will be achieved through the use of western blot and Na+ transport assay.
Oestrogen receptor α-positive (ER+) breast cancers represent the majority of breast cancer diagnoses in New Zealand. ER+ breast cancer is commonly treated with drugs that block oestrogen activity such as tamoxifen to inhibit tumour growth, with variable success. Immunotherapy has been successfully used as a treatment in other cancers, but its potential in breast cancer has not yet been realised. The aim of this project is to further understanding of the immune response to oestrogen deprivation in breast cancer. Thus, the potential of immunotherapy and oestrogen deprivation in combination, as a therapy for breast cancer, will be further determined.
The summer research project aims to identify the hypothalamic neurons in which activation of beta-catenin-mediated signalling in the hypothalamus can be identified in the rats after feeding. Brain tissue samples from fasted and re-fed groups of rats have already been collected, and the project will entail using dual label immunohistochemistry to identify which populations of hypothalamic neurons are showing feeding-induced increases in beta-catenin. We hypothesise that feeding-induced beta-catenin will be found in neurons known to be involved in body weight regulation, including the NPY/AGRP neurons in the arcuate nucleus, and oxytocin neurons in the paraventricular nucleus of the hypothalamus.
JOSHUA QUONO (Dr Lianne Parkin, Department of Preventive and Social Medicine, Dr Jack Drummer and Associate Professor Katrina Sharples, Department of Medicine, Dunedin School of Medicine)
Title: Are clinicians prescribing beta-blockers to New Zealanders with lung disease and co-morbid heart disease?
Historically, the use of beta-blockers has been avoided in patients with COPD due to a fear of exacerbating respiratory symptoms. International guidelines recommend beta-blocker use following heart attacks, even in patients with COPD. Moreover, recent evidence suggests that cardio-selective beta-blockers actually provide benefit to COPD patients. Despite this, studies in several countries have found that people with COPD and co-morbid heart disease are being under-treated with beta-blockers. No similar study has been performed in New Zealand. This research will describe real-life prescribing behaviours and address a knowledge gap about the use of beta-blockers by patients with COPD in New Zealand.
Conventional kinases add phosphate groups to specific amino acids, to regulate protein activity. Interestingly, a non-functional family of kinases, the Tribbles psuedokinases, have an alternative role. Tribbles proteins recruit substrates to COP1, an enzyme which tags other proteins for degradation. Upregulated in many cancers, Tribbles recruit a variety of important proteins to COP1, leading to the degradation of proteins involved in both cellular growth and proliferation. One degraded protein, CDC25, is a component of a vital cell cycle checkpoint, where enhanced degradation is often catastrophic. As yet, this interaction has not been extensively characterised; this research will examine this.
Gotu kola herb is used in traditional medicine to treat varicose veins and other conditions including reported beneficial effects in epilepsy. The effect is attributed to high levels of pentacyclic triterpenoids (chemical compounds) this edible plant produces. Intractable epilepsy is defined as uncontrolled epilepsy, refractory to treatment with available or tolerated medications, which leads to significant loss of quality of life. We aim to adopt a new model for intractable epilepsy using tadpoles of the frog Xenopus laevis so that extracts from the Gotu kola herb can be tested for their ability to protect the brain from seizures.
From a biomechanical perspective, it appears to be reasonable to consider the Achilles tendon (AT), the calcaneus and the plantar fascia (PF) as a functional complex, and many treatments for plantar fasciitis are based on this assumption. However, little morphological evidence exists regarding the hypothesis of a functional continuity between AT and PF, and there are conflicting descriptions of the anatomy in the existing literature. This summer student project, jointly conducted by Radiology and Anatomy, will investigate the functional relation of the three structures, AT, calcaneus and PF, using state-of-the art imaging, dissection and histological techniques. We will also further investigate any spurs found, to shed light on their structure, development, and associated changes to surrounding tissues.
Can a norovirus protein stop the cell cycle? The human norovirus is a huge economic and health burden to New Zealand. There is no reliable way of growing human norovirus for research. Therefore, mouse norovirus is used as a substitute. Our lab has revealed that the mouse norovirus can stop the cell cycle in an infected cell and that this is caused by a protein called VPg. However, the mouse norovirus may not fully represent human norovirus. This project will investigate whether human norovirus VPg protein can also stop the cell cycle, allowing us to better understand human norovirus infection.
WILLIAM WARREN (Dr Michael Jack, Department of Physics, Division of Sciences and Dr Sigurd Wilbanks, Department of Biochemistry, School of Biomedical Sciences)
Doing origami is harder in hurricanes. Likewise, protein folding is more error-prone in busy cells. Hsc70 is a protein that protects nascent proteins while they fold. This is important for preventing disease associated with misfolded proteins, and for engineering proteins with new useful functions. To understand how it does this, Hsc70 can be tracked in a live cell. However, the data are hard to interpret. This project will compare two analytical methods, one with precedent in the field, and one novel approach, in order to assess the viability of the novel approach.
Title: Newly discovered protein has no effect on relaxation of cardiac muscle, despite its key role in relaxation of skeletal muscle
Relaxation of cardiac muscle is essential for adequate heart function, without it the efficiency of the heart as a blood pump is reduced. Previous research has shown that a newly discovered protein, named myoregulin, has a significant role in inhibiting skeletal muscle relaxation. Therefore, this study aimed to determine the function of myoregulin in cardiac muscle and if it may influence relaxation of the heart. To do this, we exposed isolated heart preparations to myoregulin and measured key relaxation parameters. Contrary to our hypothesis, we found that myoregulin did not have any effect on relaxation of isolated rat heart preparations and therefore does not have a significant role in regulating the relaxation of the heart. Despite this, the continued discovery of new proteins that influence muscle function, whether cardiac or skeletal muscle, provides a means of understanding how these muscles work and, in turn, how these proteins may influence disease development.
Heart disease is the major cause of death for diabetics. For the heart to contract, it requires calcium ions, Ca2+, which is released from Ryanodine Receptors (RyR2) inside the cell following an electrical trigger and mediates contraction. However, it can also be released spontaneously which can trigger arrhythmias. In diabetes elevated blood glucose increases O-GlcNAcylation levels. This involves the attachment of sugar to proteins, and may potentially contribute to protein structural and functional impairment. The aim of this project was to determine if O-GlcNAcylation can alter the activity of RyR2. To observe this, molecular assays and Ca2+ imaging were undertaken of a cell line similar to heart cells. Our results showed inhibition of O-GlcNAcylation to have no increased occurrence of un-triggered Ca2+ release in HEK293 cells. However, promoting O-GlcNAcylation resulted in an increased occurrence of these events. This suggests that RyR2 is O-GlcNAcylated and that it increases the level of spontaneous Ca2+ release and may help explain why diabetics have more arrhythmias.
Health promotion values the competencies of advocacy, enablement and mediation to develop population level interventions that target the environment of communities and individuals to improve health outcomes. This exploratory cross-sectional study has investigated the profile and professional development needs of the NZ health promotion workforce through the use of an online survey. The survey included questions around organisation, role, personal characteristics, values and competency application. Overall 499 self-identified health promoters responded from a diverse range of organisations and geographic locations. The study has shown that the workforce requires upskilling and support, however, cultural diversity, a high level of competence, and satisfaction with workplace and job was displayed. Overall, a positive depiction of the workforce was seen. The results of this study will help to guide future workforce development within NZ and will form the basis for future studies into the workforce.
Invasive fungal infections are a major global health issue causing 1.5 million deaths annually. New drugs are urgently needed due to the increasing number of immunocompromised patients and resistance to existing antifungal medication. In this summer studentship project we analysed sites that potentially affect drug interactions within the essential fungal enzyme lanosterol 14- demethylase. This enzyme is the target of azole drugs and is required for the production of ergosterol, an essential component of fungal cell membrane. In this project, mutations introduced in amino acid residues around the active site of the protein were used to assess their potential as drug targeting features. We found that these mutations increased susceptibility to certain antifungal drugs, and may aid in the development of next-generation antifungals.
Mycobacterium tuberculosis (TB) is a worldwide killer that claims 1.5 million lives each year. The drugs available to treat TB are running out, as resistance develops faster than we can kill the bacteria. Therefore, we need to develop new therapeutic agents to help those afflicted with TB. Energy generation was recently identified as a viable target for new antibiotics and this project specifically investigated the energy-generating malate:quinone oxidoreductase (MQO). Progress was made on creating several genetically modified strains that will be essential for understanding the role and druggability of MQO.
Title: Identifying cancer-associated mutations within the New Zealand population using high resolution melting analysis – developing new methods to improve the diagnosis of cancer
Alterations in the DNA sequence of some genes can predispose individuals to a higher risk of developing various cancers. Other changes occur during cancer development and can be used for cancer diagnosis and as prognostic markers. This project used a modified version and existing method known as high resolution melting (HRM) analysis as a cheap and simple approach to identify these cancer-associated mutations. HRM analysis was used in this study to identify mutations in BRCA1 and PIK3CA genes, both of which are involved in the development and progression of various cancers. The modified HRM demonstrated greater sensitivity than more traditional techniques for identifying mutations such as DNA sequencing. These results demonstrate the potential of this HRM technique as a cheap and simple way of identifying cancer-associated mutations.
Maternal obesity during pregnancy is known to increase the risk of offspring obesity, however the mechanism underlying this is poorly understood. A region in the brain, called the arcuate nucleus is central to controlling how much food we eat. When a fetus undergoes gestation in an obese mother, key genes involved in development of the arcuate are reduced. It is thought that this is due to altered epigenetic (non-genetic influences on gene expression) control. This project aimed to investigate in mouse embros if in utero exposure to maternal obesity alters the distribution of a repressive epigenetic marker in the arcuate nucleus of the offspring. The repressive epigenetic marker was found to be increased in the arcuate nucleus of fetuses exposed to maternal obesity. This finding supports the idea that epigenetic changes may underlie the increased risk of obesity in offspring exposed to maternal obesity.
Developing new strategies to combat cancer is a growing challenge for medical researchers worldwide. In recent years, therapies which stimulate the body’s defences to fight cancer have had renewed interest. In this study, we aimed to produce two vaccine formulations which could be used to induce protective immunity in a mouse model by linking a known immune activator to the skin cancer component ‘gp-100’. As well as this we aimed to confirm previous studies which used the model antigen ‘OVA’ also linked to the immune activator. By linking activator to cancer component, we aimed to provoke an effective immune response in mice against the cancer, leading to its removal by effector immune cells in the body. Our study successfully confirmed previous studies on the model antigen ‘OVA’ showing an enhanced anti-tumour immune response by the linked compound. This is to be repeated with the tumour antigen ‘gp-100’ in the future.
Recent breakthroughs now enable researchers to precisely modify or edit specific DNA sequences in humans, plants and microorganisms. This project focused specifically on CRISPR/Cas9. The system acts as ‘molecular scissors’ that enable researchers to ‘cut’ and modify specific sequences of DNA. This research project looks to optimise CRISPR/Cas9 in pathogenic bacteria, in particular, pseudomonads. This included validating the specificity of the CRISPR/Cas9 system and investigating different methodologies of introducing the CRISPR/Cas9 system in pseudomonads. The experiments conducted was able to show that certain methods display considerable promise of successfully introducing CRISPR/Cas9 into pseudomonads. Successfully introducing the gene editing tool in the bacteria will give researchers the ability to modify specific sequences of DNA. This will be highly valuable in the investigation of virulence and antibiotic resistance in the human pathogen Pseudomonas aeruginosa.
Glioblastoma (GBM) is the most common, aggressive and lethal form of brain cancer worldwide. Survival times and responses to treatment vary widely, but all patients receive the same treatment. The molecular subtype of the GBM underlies this variability, however these subtypes currently cannot be distinguished by histopathology, a routine diagnostic lab method. This research project investigated the histopathological features of New Zealand GBM patient cases with the aim of establishing a rapid and inexpensive diagnostic tool that could allow for personalised treatment. A particular arrangement of cells known as pseudo-palisading was observed and found to be significantly associated with a molecular subtype of GBM. Additionally, it was discovered that pseudo-palisading is also associated with other specific features of GBM tumours. These findings have the potential to be useful in a diagnostic lab setting and could ultimately lead to improved health outcomes for patients with GBM.
Diabetes mellitus (DM) is a highly prevalent disease that can result in cardiovascular outcomes that may be fatal. CaMKII is a protein that shows increased activity in DM-associated cardiovascular outcomes and in response to α-adrenergic receptor (α-ADR) stimulus. It can increase and decrease activity of downstream proteins that are involved in the normal contraction and relaxation of the heart. Our aim was to determine whether an α-ADR stimulus in the presence or absence of CaMKII contributes to the cardiovascular pathology seen in DM. Our results in isolated rat hearts show that DM hearts have poor contractility basally, and CaMKII could be playing an inhibitory role on speed of contraction and relaxation in DM hearts, but helps increase speed of relaxation in non-DM (NDM) hearts. There is no difference in the expression of total or phosphorylated CaMKII between DM and NDM hearts and thus there may be another way by which CaMKII is being over-activated.
Tumours commonly spread to the brain and currently we are unable to predict which tumours will do so. Previous research carried out suggests that tumours which use a specific mechanism, the Alternative Lengthening Telomere (ALT), are more likely to spread. This study aimed to determine whether brain metastases express two ALT-associated mutations: alpha thalassemia/mental retardation syndrome x-linked (ATRX) and isocitrate dehydrogenase 1 (IDH1). 114 samples were tested for these markers using routine immunohistochemistry. This study found that ALT-associated mutations in brain tumour metastases were more common than ALT in primary tumours suggesting that brain tumour metastases are more likely to use the ALT mechanism. If this is true, it would make an easy transition into a clinical setting for an early indication of tumours likely to spread to the brain. However, further research is required to confirm if ALT-associated mutations can be a reliable surrogate for ALT.
Individuals with fetal alcohol spectrum disorder (FASD) have mental and/or physical impairment. FASD results from alcohol exposure during pregnancy. The objective of this study was to investigate the effect of a single binge alcohol exposure on acute cell death in the cingulate cortex. The cingulate cortex is an important forebrain area involved in complex cognitive functions and any damage here will impact on learning. This study used a rat model, where a single binge of alcohol was given to rat pups on postnatal day 6 or 8, a period of rat brain development equivalent to brain development of the human fetus during the third trimester. The study quantified the dead cells, 12 hours after giving alcohol using a protocol called ‘unbiased stereology’. The alcohol exposed animals had a significantly greater number of dying cells compared to those without the exposure. The finding highlights the importance of not drinking alcohol in pregnancy.
The purpose of this study was to isolate carbapenemase encoding plasmids to determine its molecular context in carbapenem resistant gram-negative bacteria isolated from patients in Myanmar. Conjugation experiments were conducted to obtain trans-conjugates along with electroporation to obtain trans-formants. Confirmation of these trans-conjugates and trans-formants were done by polymerase chain reaction (PCR). One trans-conjugate was obtained through the conjugation method and six trans-formants were obtained from all 6 isolates. These results provide the material for further analysing how the carbapenemase gene is transferred to different bacteria and hence provide useful information in reducing carbapenem resistance and furthermore combat the increasing problem of its dissemination.
Discovering new antimicrobial agents with novel modes of action is the only way to prevent the onset of a post-antibiotic era. Synthesis of a family of gold(I) triazolylidenes which have been shown to have good antimicrobial activity has been completed. Conversion into cationic analogues via substitution of the chloride ligand for a triphenylphosphine ligand was also completed. Preliminary biological testing has shown antimicrobial activity against both methicillin-resistant Staphylococcus aureus (MRSA) and Escherichia coli, and stability against biological nucleophiles.
It is understood KCa3.1 is synthesised within the cells of the human body. This channel is required to move from its synthesis station (Point A) to the membrane of the cell (Point B). In order for KCa3.1 to function, it must undergo correct movement to the membrane with the assistance of accessory proteins also called SNARE proteins. KCa3.1 is a channel, which is critical in nutrient and waste exchange in the body. Impairment to the movement of KCa3.1 can result in disease like ulcerative colitis (UC), a type of inflammatory bowel disease, and is commonly caused by the down regulation in KCa3.1 within the intestinal cells. This project focused on the interaction of the SNARE proteins with KCa3.1 in an epithelial cell line. An interaction was established for two of the three SNARE proteins with the channel. These data will enable future studies to focus on potential therapies and drugs for patients suffering from diseases such as UC.
GINNY NIEMI (Professor Sarah Hook, School of Pharmacy & Associate Professor Roslyn Kemp, Department of Microbiology & Immunology, School of Biomedical Sciences)
Colorectal cancer (CRC) is one of the most common and deadly cancers in New Zealand. In order to research this disease, animal models, which give accurate data that can apply directly to humans, are required. In this study, a previous mouse model of CRC was improved to meet better animal welfare standards, surgical standards, and to be performed in a new animal facility. A new protocol was developed and tested. Major changes to the protocol, such as using gas anaesthetic and performing the surgery in sterile conditions, may affect the mouse immune system. Therefore, data from this modified surgery will be compared to data from a previous surgery protocol to investigate any changes in immune response, which could affect results. This mouse model of CRC could be used in a variety of research, such as the testing of CRC treatments or preventative therapeutics.
Title: Quality of life for people with a stoma. Does this differ according to the underlying disease process?
There are around 500 people in Dunedin, Central Otago and Southland who live with a bag on their tummy, where their bowel opens to empty its contents. It is called a stoma and it is formed most commonly in surgery for bowel cancer, but can be formed for other conditions such as inflammatory bowel disease. A survey was completed alongside an audit of the participant’s medical records. The aim of the research was to identify how the underlying disease relates to quality of life with a stoma which had not been described in previous research. In this study, we found the quality of life was not significantly different in those who had bowel cancer compared to people with inflammatory bowel disease. The next step is to complete a more in-depth analysis of the relationship, considering the other quality of life scores and more of the clinical audit data.
Adjustment to living with an implanted cardiac device is complex, while most people respond well, others struggle. Collecting patient reported outcomes (PROs) will provide better understanding to the way people adjust to living with an implantable cardiac device. This studentship assessed the feasibility, and established a means, of prospectively collecting PROs in those living with implantable cardiac devices. Data collected will establish normal patterns of psychosocial adjustment, better identifying patients who will benefit from additional care. Analysis will identify common issues facing patients, informing rehabilitation support practices. Expectations and self-confidence in self-care will be investigated, as potential determinants of psychological distress and maladjustment. From this, the effectiveness of targeted interventions can be designed and tested. This study will inform which measures should be included when developing a nationwide PROs programme. Collecting PROs nationally will overcome District Health Board dependent variations in cardiac device populations.
Melanoma is considered one of the most aggressive human cancers. Cancers arise when cells acquire DNA mutations that result in uncontrolled cell growth. Some cells can then cease to proliferate and may become migratory. The Y-box-binding protein 1 (YB-1) has been implicated in both cell proliferation and migration. The aim of this research was to investigate two molecular sites on the YB-1 protein (S176 and S165) in four human melanoma cell lines, which may underpin the ability of melanoma cancer cells to transition from this proliferative to migratory phenotype. The results from this study suggest that two sites on YB-1 may be potential molecular targets for melanoma therapy for patients. In summary, YB-1 plays a critical role in melanoma progression and understanding this behaviour is critical to help prevent the spread of cancer.
Title: The effect of multiple medication usage on hospital admissions and death in older kidney disease patients
It is unknown whether multiple medications (polypharmacy) are beneficial or harmful. Even less is known about the risk of multiple medications in patients with kidney disease. This study investigated what effect polypharmacy had on hospital admissions and death in a group of older kidney disease patients. This study utilised data collected in a previous study on the medications use, hospitalisations and death of older New Zealand kidney disease patients over a three-year period. Increasing numbers of medications were associated with worse health outcomes. Each additional medication increased the risk of death by 8% and showed a tendancy to increase hospitalisations. Each ‘medication group’ increased the risk of death by 11% and had a similar effect with hospitalisation. The study identified specific medication groups responsible for these associations. In conclusion there is an association between increased medication use and unfavorable health outcomes.
In very premature new-born infants nutritional intake is vitally important. For various practical reasons the prescribed nutrition cannot be given, so little is understood about the actual amounts of nutrition that is received by comparison. This project aimed to explore whether the aid of a nutritional calculator tool that displays information in graphical form would be useful in clinical practice. The tool was developed as part of the research, with an audit of nutritional intake being done for several patients. The tool also allowed for nutrient levels to be compared with established guidelines. Clinicians were surveyed after seeing it in use as to how they found it and whether they would use it. There was a positive response to the tool, with the potential for it to be implemented into everyday use, to provide better care for premature infants.
Batten disease refers to a family of fatal inherited diseases that primarily affect children causing visual, cognitive, and motor problems. A genetic mutation causes one form of Batten disease that also occurs in mice. These mice exhibit reduced dendritic spine density in the cortex of the brain. However, spine density and morphology in the hippocampus, a region important to sleep, have not been investigated. Hippocampal degeneration may contribute to the sleep disturbances seen in Batten disease. Total sleep time, slow wave sleep time and delta wave power spectral density were quantified. Qualitative observations were made of hippocampal dendritic spines in mice with Batten disease as compared to healthy controls. The results of the study suggested a higher number of awakenings in mice with Batten disease, but no significant conclusions could be made as more animals are required for analysis.
Diabetes Mellitus (DM) is a highly prevalent disease which can result in cardiovascular outcomes that may be fatal. CaMKII is a protein that shows increased activity in DM-associated cardiovascular outcomes and in response to -adrenergic receptor (-ADR) stimulus. It can increase and decrease activity of downstream proteins that are involved in the normal contraction and relaxation of the heart. Our aim was to determine whether -ADR stimulus in the presence or absence of CaMKII contributes to the cardiovascular pathology seen in DM. Our results show that heart rate is lower in DM hearts but can be increased by CaMKII inhibition, CaMKII is needed for a response to -ADR stimulus, and that CaMKII may be overexpressed in DM hearts as inhibiting it showed a normal response to -ADR stimulus in DM hearts.
ISABELLE van HOUT (Associate Professor Grant Butt, Department of Physiology, Otago School of Medical Sciences, and Associate Professor Michael Schultz, Department of Medicine, Dunedin School of Medicine)
The colon is home to trillions of bacteria, which are prevented from entering the body by the epithelial lining that forms a physical barrier. The barrier is constantly renewed, with a balance between cell proliferation and cell death maintaining its normal structure. Consequently, alterations in either cell proliferation or death can affect the barrier function and allow bacteria to enter the body. This can result in inflammation, leading to pathologies such as Inflammatory Bowel Disease. Here human colonic organoids, an in vitro model of the colonic epithelium, have been used to investigate the impact of growth factors and bacteria on the rate of proliferation and cell death in the epithelium. This will help us to better understand how the cellular proliferation and death is controlled in the colon.
The purpose of this project was to knockdown the expression of two proteins, Arkadia and RNF12, in breast cancer cells. These proteins are of interest as they enhance the activity of a molecular pathway that promotes metastasis, the main cause of mortality in breast cancer. Knockdown was achieved using shRNA which cause degradation of the target mRNA and hence reduce the overall level of the protein in the cell. Five different shRNA constructs targeting Arkadia and three different constructs targeting RNF12 were tested to determine which was the most effective at reducing the expression of each gene. The best constructs gave 40 and 60 % knockdown of Arkadia and RNF12, respectively, at the mRNA level. These findings will allow the use of these shRNA in future investigations to determine how important these proteins are in metastasis and other breast cancer cell behavior.
BETH DENNIE (Associate Professor Colin Brown, Department of Physiology, Otago School of Medical Sciences)
Certain brain cells have been shown to change their signalling activity to other brain cells during pregnancy and breast feeding. A molecule called kisspeptin is thought to be the main factor in causing these changes. We looked to see if these brain cells expressed a certain receptor and whether this was increased during pregnancy and breast feeding, to show a mechanism of how kisspeptin could cause the changes seen in these brain cells. We used the brains of female mice either non-pregnant, pregnant or breast feeding and stained for the brain cells and secondly for the receptor. We found that these brain cells did express this receptor however there wasn’t an increase in its expression during pregnancy and breast feeding. This suggests that kisspeptin may be acting via another receptor or via a larger pathway via other cells to cause the changes seen in pregnancy and breast feeding.
Following a heart attack it has been observed that the amount of certain small molecules, termed microRNAs (miRs) is altered in the heart. One such molecule, known as miR-34a, has been shown to increase in the heart and blood. Release of miRs is speculated to be a mechanism of communication between different cells. In this study, we measured the effect of miR-34a released from cardiomyocytes (HL-1) on cardiac stem cells (CSCs). CSCs and HL-1 cells under high glucose stress (20 mM) were found to release more miR-34a into the media than in normal glucose conditions. Following treatment of CSCs with the conditioned media we observed no significant change in miR-34a within the cells, cell death or cell replication. However, the CSCs demonstrated reduced expression of senescence marker when treated with 20 mM glucose media or 30 mM HL-1 conditioned media suggesting high concentrations of glucose reduces the senescence characteristic of the cells (i.e. an inability to replicate).
DANYON GRAHAM (Associate Professor Brian Monk, Department of Oral Sciences, School of Dentistry and Dr Rajni Wilson, Faculty of Dentistry)
Mutations in yeast lanosterol 14-demethylase (Erg 11p) can reduce the susceptibility of pathogenic fungi to the well-tolerated and widely-used triazole drugs, limiting therapeutic options. A Saccharomyces cerevisiae hyperexpression system was used to investigate the effects of two common, clinically relevant mutations (Yl40H and I1471T) in Ergllp. Cell-based and molecular analysis revealed that the Y l40H + I1471T double mutation conferred resistance to short-tailed but not medium or long-tailed azoles. The chemistry of the linkage between the haem-bound triazole head group and the rest of the drug, together with a medium length tail, may stabilise the drug in the binding cavity and limit the desensitising effect of the double mutation. Improved design of medium­ tailed azole drugs may lead to a new generation of antifungals that will circumvent the resistance problem.
Coeliac disease (CD), an increasingly common disorder, is a chronic small bowel gut disease precipitated by eating dietary gluten. Over the last 50 years, the incidence of CD has increased worldwide. The changing epidemiology of CD in NZ has not been well documented. The aim of this study was to describe the characteristics of CD in the Otago population from 1981 to 2010. A list of possible CD cases was obtained from multiple databases at Dunedin Hospital. Diagnosis was confirmed by checking small bowel biopsy results. Lists for each year were incomplete, except 2005. For this year the age-standardised incidence rate was 16.8 per 100,000 persons, which was higher than reports from Canterbury, the UK and Italy at a similar time, suggesting the incidence of CD in Otago has increased. Practitioners must consider the diagnosis of CD in patients seen with varying presentations.
NAVNEET LAL (Associate Professor Phil Sheard, Department of Physiology, Otago School of Medical Sciences, and Dr Tania Slatter, Department of Pathology, Dunedin School of Medicine)
Muscular weakness is a hallmark of aging and occurs through loss of skeletal muscle mass, by loss of muscle cells (myofibres; myofibre death) or by a reduction in their diameters (myofibre atrophy). Dying myofibres were only recently discovered by our lab, in mice, and appeared strikingly similar to myofibres in diseases where autophagy (process of self-eating to remove damaged proteins) had become insufficient. Here, I aimed to describe changes in autophagy within dying human myofibres and whether autophagy was effective, by quantifying the autophagic substrate, p62. I also compared these results with my findings from murine models. Consistent with previous findings, autophagic activity was increased in dying versus normal myofibres. However, p62 was not elevated, but accumulated within identical autophagic structures, in similar proportions, as those identified in dying mouse myofibres. These results suggest that autophagic dysfunction in human myofibres occurs in the same autophagic structures as dying mouse myofibres.
Title: Is there a relationship between nail biting and/or thumb sucking and the development of asthma?
The Hygiene Hypothesis suggests that exposure to bacteria decreases the risk of allergies. Childhood thumb-sucking and nail-biting introduce bacteria into the mouth. It is not known whether these habits influence allergy development. Using data from the Dunedin Multidisciplinary Health and Development Study we assessed whether children who sucked their thumbs or bit their nails were less likely to have allergies and asthma when they grew up. We found that 31% of children were frequent thumb-suckers or nail-biters. These children had a lower risk of allergy at ages 13 and 32; children with both habits had the lowest risk. Thumb-sucking and nail-biting were not associated with asthma at either age. These findings show that thumb-sucking and nail-biting are associated with a lower risk of allergy.
SIMONETTE MALLARD (Associate Professor Lisa Houghton and Professor Rosalind Gibson, Department of Human Nutrition, Division of Sciences, and Andrew Gray, Department of Preventive & Social Medicine)
Title: The nutritional adequacy of the diets of HIV-exposed and -unexposed infants in urban Zambia in relation to subsequent growth
Dietary diversity, defined as the number of food groups consumed, is used by the WHO as a proxy measure of the adequacy of vitamin and mineral intakes in the monitoring of infant feeding. However, the relationship between dietary diversity and vitamin and mineral adequacy may have weakened with the growing popularity of fortified infant foods. We assessed whether dietary diversity was associated with vitamin and mineral adequacy in HIV-exposed and -unexposed Zambian infants at 6 months of age, and also whether dietary diversity and vitamin and mineral adequacy were linked to growth to 18 months. Consumption of iron-rich, fortified, animal-source, and dairy foods showed better correlation with vitamin and mineral adequacy than did dietary diversity. Nonetheless, dietary diversity had a positive effect on subsequent growth in height that was separate to .that of vitamin and mineral adequacy, warranting its continued monitoring and further investigation into the mechanisms underlying this finding.
ERIN McKERGOW (Dr Lianne Parkin, Department of Preventive & Social Medicine, and Dr Ben Wheeler, Department of Medicine, Dunedin School of Medicine)
Type 1 Diabetes Mellitus (T1DM) is lifelong disease requiring insulin delivered by injection or a pump. Some patients find pumps more convenient and blood glucose levels may be better controlled, reducing the risk of complications. PHARMAC has funded pumps since 2012, but there has been no research into the impact this has had on pump use. Our aim was to estimate the proportion of New Zealand patients with T1DM who used pumps in the years 2012 to 2014, overall, and according to patient demographic characteristics and region. Proportions were calculated using anonymised patient information provided by the Ministry of Health. Pump use increased annually, with almost 10% of patients using a pump by 2014. The greatest increases were seen among females, children, New Zealand Europeans, higher socioeconomic groups, and in some specific regions. We conclude that here are demographic and regional disparities in pump use which require further investigation.
Title: Investigating gene expression changes in a family with an inversion on chromosome 5 associated with myelodysplastic syndrome
Myelodysplastic syndrome (MDS) is a set of cancer like conditions within the blood, the severity of which can range from anaemia to an impaired immune system. The aim of this research was to investigate possible genes involved in the development of MDS using a family with a predisposing genetic abnormality. We predicted that one or more of the genes around this abnormality would be affected and display abnormal levels within blood cells. In order to investigate this we separated the blood into neutrophils and other white blood cells. These were broken down and specific candidate gene expression levels within the cell were measured using a technique called RT-qPCR. Specific primers were designed and evaluated prior to being used to investigate the family’s neutrophils and white blood cells. No significant results were obtained from this analysis.
MATTHEW PAGE (Dr Emma Wyeth, Department of Preventive & Social Medicine, and Professor Rob Walker, Department of Medicine, Dunedin School of Medicine)
Differing methods and inaccuracies of ethnicity data collection pose issues for planning and provision of healthcare and monitoring of health outcomes for various ethnic groups. This study used self-reported ethnicity data collected in the ‘Dialysis Outcomes in those aged 65years’ (DOS65+) study, to investigate the accuracy of two other sources of ethnicity data: the Australia and New Zealand Dialysis and Transplant Registry (ANZDATA), and DOS65+ participants’ clinical records. This study found high levels of agreement between self-reported ethnicity in DOS65+ and ethnicity recorded in both ANZDATA and clinical records. This has positive implications for future health planning and analyses.
URSULA POOLE (Dr Martyn Williamson and Dr Jim Ross, Department of General Practice & Rural Health, Dunedin School of Medicine)
Everyday New Zealanders are diagnosed with diseases such as diabetes or asthma. These diseases normally need life-long support from a lot of places, including the person’s family, their GP, the nurse at the practice, a specialist at the hospital, organisations like the Blind Foundation or Work and Income. One way of seeing how important all these different things are to the person’s wellbeing is by mapping them from an interview. The person is put into the centre of the map. The different sources of care are put into circles which can be closer or further away from them. This project studied what these maps looked like in people living in a small rural town. It found that people with family support, a sense of belonging to the community or who have ways of managing their disease by themselves, felt well looked after. The maps help GPs understand their patients in a broader way and identify gaps in their care.
The aim was to create a formulation for tuberculosis that infected the lungs. Pyrazinamide and moxifloxacin hydrochloride were combined to create a powder that could be inhaled. These drugs were aided by two excipients, L-leucine and 1,2-dipalmitoyl-sn-glycero-3- phosphatidylcholine. The powders were created using the BUCHI B-290 Mini Spray-dryer which produces the dry powder from a solution by continuously spraying the solution into smaller droplets followed by drying. An in vitro lung model called the next generation impactor was used to test the ability of the powders to reach the deeper lung. The results showed that after spray-drying the particles are spherical in shape with a size of <5 µm indicating suitability for deep lung delivery. The powder composed of both the drugs and 10% L-leucine showed effective delivery with approximately 70% of the inhaled drug reaching to the deeper regions of the lung.
DARREN RITCHIE (Professor Barry Taylor, Dr Gloria Dainty and Associate Professor David Reith, Department of Women’s & Children’s Health, Dunedin School of Medicine)
New Zealand is facing a childhood obesity epidemic, with approximately 33% of children being classified as overweight or obese. This is a significant public health issue due to obesity being a major determinant of childhood health, quality of life, and well-being. However, despite the evidence concerning the outcomes of childhood obesity, there has been a lack of research into tools that support appropriate assessment and management as part of routine care. Our research tested the value of such a tool developed in Dunedin. We found that our tool leads to an improvement in the completeness of assessment in over half of the categories we tested against. Additionally, our research suggests improvement in the patterns of lab-test ordering, and clinical management, which may have additional benefit. This is an important finding as it shows that standardised tools have a role in supporting the high quality assessment and management of childhood obesity.
CHANTELLE ROSSOUW (Professor Mauro Farella and Dr Joseph Antoun, Department of Oral Sciences, School of Dentistry, and Associate Professor Tony Merriman, Department of Biochemistry, Otago School of Medical Sciences)
The purpose of this study was to investigate the association between anterior open bites (AOBs) and genetic factors and to determine the facial traits of AOB patients. Nineteen AOB patients and 73 control patients were identified using radiographic tracing techniques. DNA was then extracted from existing blood samples of each patient and genetic analysis was completed on the growth hormone receptor (GHR) gene. A significant preliminary association between AOBs and the GHR gene was discovered from the genetic analysis. Further, it was found that the gonial angle and overbite depth indicator were characteristic facial traits of open-bite patients. Although individual facial traits are the result of many small underlying factors, a significant association between such AOB cases and the GHR gene may provide predictive measures for such patients in the future.
Tuberculosis (TB) is the leading cause of death by an infectious agent (Mycobacterium tuberculosis). Understanding the immune response following infection is essential to develop new immune­modulating treatments. Dendritic cells (DCs) activate important cells to initiate immune control of TB infection. There are many different DC subtypes and little is known about their role in the early response to TB. The aim of this project was to establish a method to detect whether DCs infected with mycobacteria (a model for TB) could activate other immune cells (T cells). DCs isolated from infected lungs were cultured in the laboratory with T cells, and activation and proliferation of T cells were measured by flow cytometry. We found that DCs isolated 7 and 14 days after infection cause T cell activation and proliferation, and therefore we can use this method to determine which DC subset activates T cells after TB infection.
Insulin producing pancreatic P-cell death and dysfunction are hallmarks of type 1 and 2 diabetes. Studies show circulating urate level is high (hyperuricemia) in people with diabetes. It has been observed that hyperuricemia alone can cause pancreatic P-cell death, but exact cell death pathways involved are unknown. Therefore, our project aimed to observe if the novel cell-death pathway, ferroptosis, is involved in hyperuricemia-induced human pancreatic P-cell death while exploring the involvement of other novel cell-death pathways such as necroptosis. We found hyperuricemia induced significant cell death but use of ferroptosis and necroptosis inhibitors did not significantly rescue the cells from cell death. Therefore the cell death pathways of ferroptosis and necroptosis may not be directly linked to hyperuricemia-induced pancreatic P-cell death.
Necrotising enterocolitis (NEC) is one of the most common and severe diseases in low birth-weight, preterm infants. It is believed to be caused by certain commensal gut bacteria which have become harmful due to the absence of probiotic bacteria. In Dunedin Hospital, the probiotic Infloran is used as prophylactic for NEC. This study aimed to investigate the action of Infloran on the bacteria that are involved in NEC. It was hypothesised that Infloran creates an acidic environment that inhibits the growth of NEC bacteria. The bacteria were cultured alone and together with Infloran in PreNan formula milk and the growth was measured over 24 hours. The results showed a significantly decreased growth in the presence of Infloran and significantly increased growth in the absence of Infloran. Also a change in pH was detected. In conclusion, Infloran does inhibit the growth of bacteria caused by NEC, and acid production is a likely mode of inhibition. Further investigation is required to fully understand the mechanism of inhibition.
AIMEE SMITH (Professor Cliff Abraham, Department of Psychology, Division of Sciences, and Dr Joanna Williams, Department of Anatomy, Otago School of Medical Sciences)
Stable memories require the creation of new proteins to strengthen neuronal connections in the brain. In healthy brains, histone deacetylase enzymes (HDACs) regulate this process to stop the memory system becoming overloaded, but an abnormal increase in HDAC activity has been linked to disorders like Alzheimer disease. Researchers seeking a cure for Alzheimer’s need to understand how, and when, HDACs are at work. We used immunohistochemistry to investigate HDAC activity, by looking at the level of histone acetylation, 12 hours after a learning event. Interestingly, despite successful learning in the test group, we did not find a difference in histone acetylation between groups, despite prior evidence that HDACs are more active at this time point. This suggests that other enzymes may be activated to stabilise histone acetylation. Further studies are needed to understand the complex inter-relationships between these molecules as memories stabilise over time.
Arteriovenous (AV) fistula, formed by connecting a vein to an artery, allows vascular access for haemodialysis in patients with kidney failure. Vein suitability is determined by a patient’s vein diameter and ability to dilate. This project aimed to determine whether 1) warm water bath, 2) warm air, or 3) handgrip exercise, was most efficient at dilating the cephalic vein, compared to current practice in the Otago Vascular Lab which is a tourniquet. The warm water bath was the most efficient and effective mechanism, and caused the highest percentage of participants to reach the threshold diameter of 3 mm. If used in clinical practice to measure vein suitability before surgery, the results suggest it would increase the number of patients put forward for AV fistula. AV fistula has a lower rate of complications than other forms of haemodialysis therefore the warm water bath could improve overall outcomes if these patients go on to form successful fistulae.
ROBERT SMITH (Dr Bill Hawkins Department of Chemistry, Division of Sciences, and Professor Parry Guilford, Department of Biochemistry, Otago School of Medical Sciences)
The E-cadherin protein acts as a tumour suppressant, the down regulation of which has been associated with the formation of metastatic cancers. The treatment options for these cancers are currently limited and the development of selective treatments is difficult due to the lack of a clearly defined intracellular target. Work by Professor Parry Guildford’s research group has identified several compounds via a high throughput screen that selectively target E- cadherin deficient tumour cells. Synthesis and biological evaluation of analogues of a specific compound was performed during the summer scholarship. The information gathered will aid in the development of a chemotherapeutic agent selective for E-cadherin deficient tumours.
Over-expression of the model fungal multidrug efflux pump Cdrlp, found in the major opportunistic fungal pathogen Candida albicans, causes multidrug resistance. This has the potential for serious consequences such as prolonged treatment or even death for the infected patient. The aim of this project was to determine whether we could employ the novel NanoBRET™ technology developed by Promega Corporation, Wisconsin, USA, to investigate possible homo-dimerisation of Cdrlp in live cells. For this purpose we created a genetically modified yeast strain that over-expressed Cdrlp to which a NanoBRET molecule was physically linked. The results from these experiments confirmed, for the first time, that the highly sensitive and robust NanoBRET technology could be used in yeast cells. We also confirmed that Cdrlp function was not significantly altered by the NanoBRET extension. We can now proceed to investigate Cdrlp homo-dimerisation in live yeast cells.
Bad breath is a significant social stigma for many people. Good bacteria called probiotic have been used to treat diseases in the mouth like tooth decay. The tongue’s rough surface provides a large area on which bad breath-generating bacteria can live. Tongue brushing can reduce bacteria on the tongue. The purpose of this study was to investigate the effect of tongue brushing and /or taking lozenges of good bacteria on reducing bad breath. Volunteers (35) either did tongue brushing and/or took good bacteria lozenges or nothing for 4 weeks. Various measures of bad breath were recorded 3 times (at the start, after 4 weeks and after 8 weeks). Bad breath was reduced by 31% 26% or 30% in the groups using tongue brushing, probiotic or the combined treatment, respectively. Our preliminary results suggest that tongue brushing and/or use of good bacteria may reduce the level of bad breath.
Batten disease is a group of lysosomal storage disorders that result in visual impairment, loss in cognitive function and premature death. Mutations in CLN6 gene cause one form of Batten disease. Pre-clinical testing of a drug called NDD-1 has been carried out on a mouse model of this Batten disease, and a previous study has shown that it decreases neuroinflammation in the cortex. In this project, a focussed analysis of three chosen regions using markers of inflammation was carried out to see if the same result was observed. This study however could not conclude a significant effect of NDD-1 in these regions which suggests that more animals/sections need to be analysed or different regions of the cortex contributed to results previously established.
JADE YORK (Associate Professor Stephen Bunn and Professor Dave Grattan, Department of Anatomy, Otago School of Medical Sciences)
One of the brain’s important roles in the body is regulation of hormone production, including that of prolactin, which has many roles, essentially the production of milk after childbirth. In order to monitor the changes in the brain that occur when increased prolactin secretion is required, technology involving genetically modified rats has been used to monitor the specific neurons involved. The objective of this project was to assess the appropriateness of this rat model for future experiments. It aimed to determine whether it is possible to accurately target the right neuron population using specific staining techniques looking at these neurons under the microscope. The findings of this report indicate the model to be appropriate and effective for further research.
MICHAEL YUAN (Dr Cherie Stayner and Professor Mike Eccles, Department of Pathology, Dunedin School of Medicine)
Autosomal recessive polycystic kidney disease (ARPKD) is an inherited disorder that results in significant enlargement of the kidneys. It is caused by defects in the primary cilia, a sensing organelle on the cell surface. One form of ARPKD, called Meckel syndrome, can be due to mutations in the MKS3 gene. This codes for the protein meckelin which is required for primary cilia function. We investigated the effect that mutations in MKS3 have on the distribution of meckelin in human kidney HEK293 cells. Each MKS3 mutant construct was introduced into HEK293 cells. This was then passed through a laser to determine the percentage of meckelin within the cell and on the cell surface. Meckel in was found to have a greater accumulation within the cell in the MKS3 mutations when compared to the MKS3 WT. As a consequence there is disruption in the meckelin mediated signalling pathways that regulate primary cilia formation.
A possible mechanism for increased antibiotic resistance in the bacterial pathogen Pseudomonas aeruginosa isolated from the lungs of cystic fibrosis patients
The majority of cystic fibrosis adults are infected with the bacterium Pseudomonas aeruginosa which can cause life-threatening illness. P. aeruginosa antibiotic resistance is rapidly advancing, so monitoring antibiotic effectiveness is essential. P. aeruginosa possesses an ampC gene which provides resistance to certain antibiotics. This project investigated whether highly antibiotic resistant strains of P. aeruginosa carry multiple copies of ampC which could increase their resistance. Most strains investigated appeared to have a single copy of ampC while two strains may have multiple copies (further research would provide conclusiveness) and one non-clinical strain may have lost ampC altogether.
In order to store information, neural synapses must be capable of regulated change. This memory-related plasticity, for example long-term potentiation (LTP), must be maintained within a functional range by metaplastic mechanisms. Previous studies have shown that single hippocampal neurons could be positively primed for increased future LTP via intracellular stimulation but not extracellular stimulation, possibly because bulk stimulation activates other types of priming. We hypothesise that hippocampal CA1 neurons can be extracellularly primed by applying MRSl754, an adenosine 2B receptor inhibitor which blocks negative priming. We found a trend supporting our hypothesis, although it was not statistically significant.
Candida albicans is the principal fungal cause of denture stomatitis – inflammation of mucosa beneath dentures. The ecology of C. albicans strains causing denture stomatitis is poorly understood. We used multilocus sequence typing to track changes in the C. albicans strains in the mouths of people following delivery of new dentures. We found C. albicans strains that were common to several individuals. Some people had more than one strain type. Some strains were maintained in individuals for up to six months despite renewal of dentures, others were acquired during the study. There was preliminary evidence for strain microevolution with time.
Our aim was to evaluate the renal clearance and dosing of metformin in subjects with reduced kidney function. Metformin 500 mg and gentamicin 40 mg (a marker of the kidney’s glomerular filtration rate [GFR]) was given to six volunteers with impaired (2 ) and normal renal function (4). Blood and urine samples were collected over 24 hours. Metformin clearance was compared to estimates of GFR using linear regression. Metformin clearance was strongly correlated with GFR (gentamicin clearance, R2 = 0.94, P <0.01), and published eGFR equations (R2 >0.90). Thus our results suggest that a proportional dose adjustment based on estimated GFR is a reasonable dosing strategy for metformin in renal impairment.
The impact of increasing iodine levels in bread on the iodine status and intakes of elderly New Zealand rest-home residents
In response to re-emerging iodine deficiency, in 2009, the NZ government mandated the fortification of breads with iodised salt. Iodine intakes and urinary iodine concentrations were determined for participants from a 2014 nation-wide survey of rest-home residents, allowing the impact of fortification on iodine intake and status to be examined. Fortification increased iodine intakes, from 66.6 µg/day to 97.3 µg/day (P <0.001). However, the post-fortification median urinary iodine concentration was 72.5 µg/L, indicitive of mild iodine deficiency. Fortification of other staple foods or supplementation should be considered as additional interventions aimed at improving the iodine status of NZ’s rest-home population.
Diabetes is a chronic metabolic disorder associated with acquiring heart disease, commonly known as diabetic heart disease. Heart disease among diabetics develops at an earlier stage than in nondiabetics. Changes in the structure and function of the heart occur as a consequence of stages at the molecular level. The expression of circulating microRNA-34a (miR-34a) and high-density lipoproteins (HDL) cholesterol were measured to determine use as a biomarker for early detection of heart disease. Results demonstrated diabetic plasma samples to have an increased level of miR-34a compared to non-diabetic plasma samples. Furthermore, HDL concentrations were lower in diabetics than non diabetics.
DANYON GRAHAM (Associate Professor Brian Monk, Sir John Walsh Research Institute, Faculty of Dentistry)
The effect of a second-site mutation on triazole resistance in yeast: A research project seeking to facilitate structure-directed antifungal drug design
Fungal infections caused by drug-resistant fungi are a serious and growing public health concern. Mutations in yeast lanosterol 14-demethylase (Ergllp) reduce susceptibility to triazole drugs, severely limiting therapeutic options. A Saccharomyces cerevisiae hyperexpression system was used to investigate the effects of two common, clinically relevant mutations (Y140H and I471T) in Ergllp. Cell-based analysis revealed that the Y140H + 1 471T double mutation conferred resistance to short-tailed but not long-tailed triazole drugs. The chemistry of the linkage between the triazole head group and the rest of the drug, together with a long tail, may stabilise the drug in the binding pocket and limit the desensitising effect of the double mutation. Improved design of long-tailed azole drugs may lead to a new generation of antifungals that will circumvent the resistance problem.
Rapid and accurate discrimination between methicillin-resistant Staphylococcus aureus (MRSA) and methicillin-susceptible S. aureus (MSSA) is essential for effective treatment and prevention of transmission. This project investigated the ability of matrix-assisted laser desorption/ionisation time-of-flight mass spectrometry (MALDI-ToF MS) to discriminate between MRSA, MSSA and the seven major MRSA strains found in New Zealand. The hierarchical analysis
created from the mass spectral profiles showed that isolates were randomly distributed. Thus, we cannot recommend MALDI-ToF MS for discrimination of S. aureus isolates beyond the species level.
Heart rate regulation and contractility are carefully modulated. In a pathophysiological system such as type 2 diabetes mellitus (T2DM), heart function is impaired and the heart is unable to meet the demands of exercise. However, the mechanisms underlying this impairment are not understood. We aimed to compare heart responses of T2DM patients to controls during pharmacological stimulation. Contrary to our hypothesis, no significant differences were seen in contractility, suggesting T2DM patients retain their ability to increase contractility and more extensive study is required to clarify the underlying pathology.
The association of serum testosterone with relationship status and parenting at ages 26 and 38 in men: preliminary analyses
Consistently serum testosterone (T) has been associated with relationship status in men, and in some studies with fathering. This was examined at ages 26 and 38 in the Dunedin Multidisciplinary Health and Development study. At both ages both total and free serum T were lower in men in long-term relationships; they were not associated with ever fathering a child, but were associated at age 38 (but not 26) with living with a child. Serum T was also associated with weight and smoking. Further analyses are planned to examine for independent effect of relationship status and of changes over time in individuals.
Brain metastases are even more common than primary brain tumours and there are limited treatments available for them. This study aimed to identify possible clinical and molecular prognostic factors for this devastating disease. Although the study had a small sample size, modality of treatment and location of tumour were found to be prognostic factors in this cohort as well as MGMT (O6-methylguanine DNA methyltransferase) and CD163 (macrophage/activated microglia associated antigen) marker status. These factors should be considered when a decision is made about how aggressively a patient is treated particularly if the treatment threatens the patient’s quality of life in their final days.
Molecules containing reactive electrophilic centres are generally discouraged from being considered as potential drug candidates and often removed from screening libraries before biological evaluation. This central belief seems unfounded when considering the $US33 billion/yr in worldwide sales generated by covalently binding drugs (including aspirin and penicillin). As a case study, we explored the rational modification of the current standard for treatment of Alzheimer’s, that of using donepezil. Reactive electrophilic centres were incorporated into different analogues to improve its binding and selectivity, which could potentially improve the drug’s half-life, cellular resistance, and dosing as well as its pharmacokinetic profile. Synthetic studies were carried out directed towards obtaining these compounds which will eventually be tested for their biological activity. The enone analogue of donepezil, where R = H, was successfully synthesised as well as donepezil itself. However analogues of donepezil, where R = Me and Et, were unable to be synthesised using an aldol condensation from the precursors.
LAURELLE LOCK (Dr Greg Walker, School of Pharmacy and Professor Vernon Ward, Department of Microbiology & Immunology)
A controlled release virus like particle (VLP) loaded with vaccine has the potential to improve the efficiency of immunisations. Nanofibre scaffolds could be used as a matrix to bind VLP as a controlled release platform. In this research we used an electrospinning technique to fabricate nanofibres with various properties known to bind VLP: polycaprolactone (PCL) for hydrophobic attraction, PCL-chitosan blend for ionic interaction and fucoidan coated nanofibres for sugar binding. Scanning electron microscopic analysis showed a stable nanofibre network had been
fabricated for all formulations, with the hydrophobic PCL nanofibre appearing to have the highest affinity for VLP.
Does weight loss improve vitamin D status? A pooled analysis of weight loss trials and bariatric surgery studies
To clarify the nature of the association between obesity and vitamin D deficiency, we undertook a meta-analysis of weight loss studies, aiming to describe the effect of decreasing body weight on vitamin D status. I developed a systematic literature search strategy, and from the 6766 articles identified, 95 met our inclusion criteria. This number was greater than anticipated, which will increase our ability to detect a significant finding. Data extraction sheets were developed and completed. Upon completion of duplicate data extraction by a second researcher, I will in future perform the meta-analyses and draft a manuscript for publication in 2015.
Noroviruses are well known pathogens but currently there is no treatment, vaccine or ability to easily grow the virus in cell lines. Mouse norovirus (MNV), however, can be propagated in the laboratory and was used in this project to investigate if exocytosis was a possible exit strategy for MNV. Inhibitors were used to block aspects of the exocytosis pathway and the effects on intracellular and extracellular virus production analysed. No change in virus production was observed, demonstrating that MNV does not require the exocytosis pathways blocked by the inhibitors to exit cells.
Spinocerebellar ataxia type-1 (SCAI) is a disorder that destroys the cerebellum – the part of the brain crucial for executing co-ordinated movements. Previous research has found hyperactivity of cerebellar metabotropic glutamate receptors (mGluRl) in the early stages of SCAI. My experiment aimed to answer the question whether this hyperactivity is helpful or harmful. I found that acute pharmacological blockade of mGluRl improved the motor performance of SCAI mice suggesting that mGluRl hyperactivity may herald the onset of harmful cerebellar destruction. Our findings suggest that moderation of mGluRl may be a good way to treat the early symptoms of human ataxia.
Diabetes Mellitus (DM) is strongly associated with cardiovascular disease and is escalating worldwide. DM-induced disease of small heart vessels, the coronary microvessels, contributes to increased cardiovascular morbidity and mortality in diabetic patients. However, our limited ability to directly measure coronary microcirculation restricts progress in our understanding of DM heart disease. I aimed to establish an innovative tool, vascular casting, to measure coronary microvascular perfusion and investigate how type 2 DM impairs this. My study supports the validity of this technique, demonstrates its potential to enhance our understanding of coronary microcirculation in DM, and generates novel opportunities for future cardiovascular research.
Insulin pumps are widely used in the treatment of type 1 diabetes mellitus (TlDM). Perhaps because of their popularity, there have been few recent studies considering the adverse events (AE) associated with their use. This study sought to describe the incidence and characteristics of insulin pump-associated AEs in New Zealand children and adults with TlDM, using a self-report retrospective questionnaire covering the previous 12-month period. We found a high rate of AEs of all types, with set/site problems most commonly reported. As AEs appear common, anticipatory patient education may therefore be important in order to minimise AB-associated complications.
Bread is a dietary staple of the New Zealand population, making it an ideal vehicle to provide nutrients known to benefit health. One such nutrient is nitrate found in beetroot. In this randomised, cross-over trial, subjects consumed bread containing beetroot juice or beetroot puree. Then blood pressure, endothelial function and gastro-intestinal acceptability were measured over a four-hour period. The beetroot bread was well accepted by participants, however there was no reduction in blood pressure or endothelial function. Fifteen more participants will be recruited to strengthen these findings and determine whether an association is present.
ANTHONY SHAW (Professor Parry Guilford and Associate Professor Mik Black, Department of Biochemistry)
Current tests for early detection of prostate cancer have relatively low effectiveness, often only being able to detect late-stage cancers, or in the case of PSA testing having high false positive rates, leading to unnecessary biopsies and potentially serious complications. Single cell sequencing provides the ability to identify urine-based ·prostate tumour biomarkers, which may offer improved diagnostic performance. By analysing data from single cell sequencing experiments we attempted to identify genes that are only active in prostate tumour cells, and accurately estimate the number of transcripts in single cells to help optimise the development of an improved urine-based diagnostic test.
An investigation into the interaction partners of a protective, Alzheimer’s disease-related, brain protein
An Alzheimer’s disease-related protein has drawn great interest because it has been shown to be neuroprotective. My project intended to begin a study to look for the interaction partner(s) of secreted amyloid precursor protein alpha (sAPP) in order to determine how it might mediate its positive effects on the brain. I carried out the first step by producing the complementary DNA (cDNA) for the gene of one potential protein partner, sortilin. I then inserted this into a larger DNA construct that can enter human cells in culture and express the protein, ready for interaction testing in the future. 6 NICOLAS THEIS (Dr Keith Ireton, Department of Microbiology & Immunology) Title: Purification of a bacterial protein essential for infection of human cells and its recruitment of human proteins to facilitate entry (Southern Trust Scholar) Yersinia species are food-borne bacteria that commonly cause intestinal disease. To establish infection, a protein on the surface of Yersinia, called invasin, interacts with a specific human receptor on the surface of intestinal cells. We aimed to purify invasin and introduce it to human cell cultures to observe its effects on human proteins associated with structural change. Introduction of invasin-coated beads to the surface of human intestinal cells resulted in recruitment of several proteins responsible for remodeling the cellular skeleton. This indicates that Yersinia invasin protein is capable of actively triggering structural changes in the human cell to facilitate infection.
Overall, the five-year survival of patients with hormone refractory prostate cancer is less than 25%. Studies have highlighted the potential of tyrosine kinase inhibitors in the control and treatment of prostate cancer. Preliminary data have shown that a combination of sorafenib and nilotinib, which inhibit pro-angiogenic factors and cell proliferation, decreases cell viability of prostate cancer cells. However, these inhibitors are extensively metabolised and inactivated in vivo. The aim of our research is to evaluate the cytotoxicity of a combination of these two drugs into the same nanomedicine against various prostate cancer cells.
As we age, we experience a progressive decline in strength and muscle mass, a condition called sarcopenia. We believe that the progressive decline in strength is caused partly by muscle denervation.Although the causes of denervation are currently unknown, our hypothesis is that it occurs due to age-related loss of synapse maintenance signals between the muscle and the motor nerve. Here I propose to investigate one such protein – MuSK, a regulatory protein that is involved in formation and maintenance of the neuromuscular junction.
Childhood obesity rates in NZ are among the highest worldwide, and one of the major modifiable determinants is diet. Measuring diet comprehensively in children using traditional pen and paper methods is difficult to do accurately. The Department of Human Nutrition has recently developed an iPod-based food diary for recording food and drink intake in adolescents, using food photography. This has proven to be a user friendly, efficient and accurate method of measuring nutrient intake in adolescents. The aim of this project is to investigate if this new app is suitable for measuring food and drink intake in younger children.
Episodic memory formation is believed to require information processing in the hippocampus. Previous work has shown that young granule cells born in this brain region during adulthood possess unique electrophysiological properties which make them more excitable and particularly susceptible to incoming information, while older granule cells “retire” from information processing. However, overall low activation rates may have biased the result of previous studies. The aim of the proposed research is to provide a more accurate estimate of the contribution of young and old granule cells to hippocampus-dependent information processing by amplifying the proportion of granule cells activated in response to behavioural exploration, through previous exposure to an enrichment environment.
Arrhythmias are irregular heartbeats that can be triggered by the spontaneous opening of a calcium channel named the cardiac ryanodine receptor (RyR2). Anti-arrhythmic drugs typically act by blocking plasma membrane ion channels or sympathetic nervous activity to alter cardiac action potentials, although recently some have been discovered to act by directly inhibiting RyR2. Currently, tools used to screen drugs for inhibiting RyR2 are time-consuming and expensive processes. This project aims to develop a higher throughput cell model to allow efficient screening of anti-arrhythmics using calcium measurement techniques. This model will help rapidly identify drugs with the potential to prevent arrhythmia.
Breast cancer is the most common cancer in women accounting for 400,000 deaths per year worldwide. The majority of breast cancers produce the oestrogen receptor and require the hormone oestrogen to grow. Drugs that act by preventing the production of oestrogen are the most effective treatment currently available for this type of cancer. However, these drugs do not work well for all patients. We plan to investigate the role of a DNA variant in controlling how the gene that encodes the oestrogen receptor is turned on. This may help us understand why treatment does not work for some patients.
Oral chemotherapy is the preferred treatment of patients and offers several advantages over intravenous administration of chemotherapeutic drugs. However, gastrointestinal (GI) toxicity and low oral bioavailability often limit the use of anti-cancer drugs via the oral route. This may be overcome by use of nanoparticles that encapsulate the drug to minimise contact with the GI wall and preferentially accumulate drug concentration at the tumor site. To date there are no approved nanoparticles in oral chemotherapy, thus here we aim to explore the potential of the SMA-paclitaxel nanoparticle construct in increasing bioavailability and antitumor efficacy.
Risk of rhegmatogenous retinal detachment in patients with various degrees of shortsightedness in New Zealand
Rhegmatogenous retinal detachment (RRD) is a medical emergency that, if untreated, can progress to visual impairment and blindness. High myopia has been found to be a significant risk factor for RRD and the risk for developing RRD is associated with a patient’s refractive error. The aim of the research is to investigate the prevalence and degree of refractive error in patients presenting with RRD in New Zealand using a multi-centre, retrospective study. From this data we hope to estimate RRD risk in people with refractive error in New Zealand and correlate the risk with the degree of myopia.
IUN KAO (Dr Greg Walker, School of Pharmacy, and Dr Michelle McConnell, Department of Microbiology & Immunology)
Wine waste extracts containing a high amount of compounds called polyphenols have been shown to kill bacteria. The aim of this project is determine whether we can incorporate these bioactives into a nanofiber textile which can then release these actives slowly over time to kill bacteria. We will make the bioactive nanofiber textile by electrospinning a solution of polymer and wine waste extracts together. Using a chemical assay for polyphenols we will measure the release of the bioactive compounds over time. These textiles will be put in contact with bacteria in the laboratory to see if they can kill the bacteria.
Mycobacterium tuberculosis is the causative agent of tuberculosis (TB), a disease that infects and kills millions of people every year. The only vaccine available does not work well to protect against TB of the lung, which is the most common form of TB. In order to develop a better vaccine we need to understand the immune populations that can recall and fight the infection effectively. As part of this effort in this project we plan to develop a test to accurately measure the features and functions of the recall (or memory) immune cells that develop after TB vaccination.
The secretion of digestive proteins by pancreatic acinar cells is a vital and highly regulated process required for the digestion of food. Defects in secretion may lead to an illness known as pancreatitis. COMMD (Copper Metabolism MURR1 Domain containing) proteins are a family of recently discovered proteins known to have a diverse role in cellular regulation including protein secretion. One of those proteins, COMMD10, is thought to have an effect on pancreatic protein secretion. This project aims to determine how COMMD10 regulates the secretion of proteins by pancreatic acinar cells.
Practice Based Research Networks (PBRNs) are internationally recognised in bridging the research gap between general practice and universities. This study launches our recently developed ARCH (Applied Research through Clinician’s Hands) dental PBRN in New Zealand. Direct pulp capping is a conservative approach for the management of pulp exposures and this project will investigate this treatment and its application in general dental practice. A survey will be sent to practitioners who have previously expressed interest in joining the ARCH PBRN with the objective of gaining information around the understanding and management of pulp exposures in general practice, and to inform future dental PBRN projects (on the ease of data collection in private dental practice).
Staphylococcus aureus is a major cause of serious skin infections and hospitalisations in New Zealand. This pathogenic bacterium commonly resides on our skin or in our noses. With the number and range of antibiotics that S. aureus is resistant to increasing in communities, it is becoming more vital to know which antibiotics are used in each region that the endemic S. aureus occurs because initial antibiotic treatment is empiric. In this project I aim to determine the antibiotic susceptibility of S. aureus strains previously isolated from Oamaru school children.
Candida albicans is an opportunistic fungal pathogen that causes serious infections in immunocompromised individuals. Treatment of patients with azole antifungals is hampered by the emergence of drug resistance. The major mechanism of C. albicans azole resistance is overexpression of the efflux pump Cdr1p. It is not known how inhibitors bind to Cdr1p or how substrates are pumped. We will use site-directed mutagenesis and a unique library of yeast expressing mutated Cdrlps to test our hypothesis that amino acid glycine 521 in Cdrlp forms a ‘gate’ with amino acids in another part of the pump that controls inhibitor binding and substrate access.
Ca2+/Calmodulin-dependent protein kinase II (CaMKII) is a protein that, when activated, is able to modify other proteins in the body and contribute to specific physiological functions. Normally CaMKII is in an inactive state in cardiac tissue. However in disease, CaMKII is modified so that it becomes hyperactive, and this process has been linked to pathologies such as cell death. Recent studies in the context of the heart have shown that diabetics have increased mortality compared to non-diabetics, and CaMKII hyperactivity has been implicated. Therefore our aim is to investigate the role of CaMKII in the diabetic heart.
Autistic spectrum disorders (ASD) include deficits in socialising, language and behaviour. ASD have a male bias, and are associated with an accelerated rate of brain development. AntiMüllerian hormone (AMR) is during development a male-specific testicular hormone which putatively controls the speed of male development. ASD boys with high levels of AMR have mild symptoms suggesting that AMR may protect against ASD by slowing development. My proposal will test whether AMR directly slows the rate of early brain development. This will be achieved by comparing the maturity of the brains of AMH-deficient (Amh-/- ) male mice with their normal (Amh+/+) male littermates.
The emergence of multidrug resistance in fungal pathogens compels the development of new classes of fungicides that do not induce drug resistance. Transciptional regulation of multi-drug drug resistance in Saccharaomyces cerevisae has provided insight into potential drug targets, including the transcription factor Pdrlp. A recent experimental approach aimed at identifying antagonists of Pdrlp has found that bactopeptone can activate Pdrlp. This research project aims to identify the component in bactopeptone responsible for the activation of Pdrlp-mediated multi-drug resistance in order to assist antifungal drug design.
Cancer treatment by cisplatin can be hindered by drug resistance and toxicity. The use of drug delivery vectors to selectively transport cisplatin to tumours to increase effective dosage and decrease toxicity is therefore a blossoming field of research. Our group has developed a supramolecular cage capable of binding cisplatin and the technologies to functionalise the cage for added solubility, stability and potential targeting. Changes can be made to improve the encapsulation of cisplatin within the cavity of the cage, and this project would develop this methodology and test its effectiveness in improving cisplatin binding.
Solid tumours contain many cells derived from the bone marrow which includes mesenchymal stem cells (MSCs). MSCs contribute to cancer malignancy and so present as good targets for cancer therapy. Coffee is a very popular drink worldwide and is made up of a large group of chemicals, including caffeine. This project will investigate the effect of coffee and its constituents on MSCs. We will show which of the constituents are able to kill MSCs and demonstrate the mechanism of cell death. This will establish how coffee may be affecting cancer development and whether it has possible use in cancer treatment.
ATP binding cassette transporters play a pivotal role in the development of xenobiotic resistance. Two highly conserved features, the pairs of nucleotide binding domains and the pairs of transmembrane domains, suggest ABC transporters may be electrogenic primary pumps because ATP hydrolysis generates protons and transported substrates are partially positively charged. This study aims to confirm the concept that overexpression of the Candida albicans Cdr1p drug efflux pump confers on yeast the ability to produce an enhanced electrochemical gradient at the plasma membrane and to test whether this applies more broadly to efflux pumps of the ABC transporter superfamily.
Choroidal melanoma encompasses 90% of all uveal (iris, ciliary body, or choroid) melanomas, and is associated with a mortality rate of 50%. The incidence of uveal melanoma is 4.3 cases per million people in the United States. Initially appearing as a small freckle beneath the retina, it can grow in height and diameter and may eventually spread to other parts of the body causing death. Most patients present with visual symptoms such as photopsia, floaters, vision loss or eye pain. Currently, there is a lack of research on choroidal melanoma in the New Zealand population. The aim of this research is to investigate how this disease is detected and treated in our country. Additionally, this will give us an opportunity to study the demographic profile and eventual outcome of the affected population.
Features of the polycystic ovarian syndrome (PCOS) are considered to be caused by impaired neuroendocrine regulation of ovarian function. Estrogen-sensitive noradrenergic neurons in the solitary nucleus (SOL) of the brain may have a role in controlling gonadrophin releasing factor (GnRH) release and ovulation. To examine possible differences in hormone sensitivity, which may impact upon GnRH release, my project examined differences in estrogen receptor alpha (ERα) expression in the SOL of fertile mice and PCOS-like infertile mice. This was performed using immunohistochemistry against ERα and ImageJ analysis to quantify differences in ERα positive cell number. There were no significant differences in ERα cells between the PCOS-like and control animals.
Alzheimer’s disease is a progressive and debilitating neurological condition that affects approximately 50,000 New Zealanders. This project aimed to investigate a novel interaction between soluble amyloid precursor protein α (sAPPα) and β -amyloid, important in the disease. This was achieved by measuring the binding between the purified proteins in isolation. Binding between the two proteins was observed, and also occurred when shorter fragments of the β-
amyloid was used. The binding, however, only occurred under specific conditions regarding the orientation of the protein. These findings may have implications for sAPPα and β-amyloid’s physiological and pathological roles.
Maintaining good control of diabetes is crucial in preventing the progression and onset of severe short and long-term complications. This is a pilot cross-sectional study investigating the relationship between intuitive eating and long-term control in young adults between the ages 18 to 25 years, with Type 1 diabetes mellitus (TlDM). Full data was obtained from 33 participants through survey monkey with glycosylated haemoglobin (HbA1c) used as a measure of long-term glycaemic control. A logistic regression showed that no significant relationship between measures of intuitive eating and metabolic control existed. Despite this, the study is the first of its kind to look at intuitive eating in the young adult T1DM population, and is part of a growing body of research looking to enhance control in this population.
A histological examination of sections preserved from a pilot study done in 2010 was carried out to determine the mechanism by which two novel hybrid resorbable sutures, containing growth factors and antibacterial agents, had increased healed wound strength compared with the unmodified control. The study indicated differences between the materials in granulation tissue per unit area that could account for the increased performance. Given the potential benefits to patients in terms of earlier mobilisation from surgery and shorter hospital stays, the results of this study suggest that larger in vivo trials to assess the efficacy of the new suture materials is warranted.
Most brain disorders differ between the sexes in incidence or severity. The testes secrete antiMullerian hormone (AMH) during childhood, whereas the ovaries do not. AMH may therefore generate sexual differences in the brains of children. This pilot study investigated whether a sexually dimorphic brain area (the medial preoptic area) shows a sex bias in the number of cells containing the enzyme tyrosine hydroxylase (TH-positive cells). It asked whether the absence of AMH during development affects this sex bias. The results indicate that this cell population is appropriate to study in further investigationsinto the role of AMH in brain development.
Obesity is a risk factor for development of cardiac disease. Knowledge of changes in underlying mechanisms determining cardiac function in humans are limited, but can be studied in trabeculae (small cardiac muscles) yielded from the right atrium (RA). We investigated whether obesity affects cardiac function differently between the RA and right ventricle (RV), and saw that trabeculae from RA and RV of lean rats showed similar cardiac responses at baseline, forcefrequency
and adrenergic stimulation. However, atrial and ventricular trabeculae in obese rats were affected differently. These disparities suggest atrial-ventricular differences with obesity, despite similar regulation of function in a healthy heart.
Pupil dilation is often required both for eye examinations and eye surgery. Many ophthalmologists avoid using these dilating drops the day before surgery, fearing they are less effective when used on consecutive days. Our study examined pupil size after routine dilation in 25 patients, of whom 10 received dilating drops on consecutive days. We found no statistically significant difference in final pupil size between these groups -indeed the average increase in pupil size was larger on the second day. We conclude that pupil dilation the day before eye surgery does not need to be avoided.
Methotrexate use in the community – identifying a gap in patients’ knowledge of the therapy as well as their awareness of safety issues
Low-dose methotrexate has been implicated in medication errors resulting in life-threatening events. Sixty rheumatology patients were interviewed to obtain information about their methotrexate use and awareness of toxicity as well as to assess the risk of potential unintentional overdose from a medication error. Education from a rheumatology nurse and shorter duration of methotrexate therapy were found to be associated with superior knowledge of methotrexate toxicity. Two patients were identified as being potentially at risk of overdose due to medication error. We would recommend that patients receive education on methotrexate by nurses and subsequent information be given after 5 years of therapy.
Child maltreatment in New Zealand is a significant burden. This online pilot study investigated health professionals’ reporting practices, barriers to reporting and mandatory reporting attitudes in the Southern District Health Board regions. Based on 63 participants’ responses to a questionnaire, 63% had suspected child maltreatment in the past year, and 37% of this group did not formally report their suspicions. Most (61%) favoured implementing mandatory reporting and 17% felt sufficiently trained to recognise and respond to maltreatment. Further research is needed to ascertain the consequences of health professionals not reporting their suspicions and how best to improve health professionals’ participation in research.
Kisspeptin is critical for puberty and fertility, and preliminary results have shown it has a centrally mediated effect on oxytocin neurons during late stages of pregnancy. Understanding the changes that occur in neuronal circuitry during pregnancy is important; therefore, the aim of my project was to investigate change in kisspeptin neuron number, and expression of an immediate early gene, cFos, in the arcuate nucleus during pregnancy and lactation using immunohistochemistry. It was hypothesised that kisspeptin neuron number and c-Fos expression would increase. Results showed a decrease in kisspeptin neuron number from day 14 of pregnancy. No significant change was seen in c-Fos expression.
Prostate cancer is the most commonly diagnosed cancer in New Zealand. In prostate cancer, there is a loss of caveolae and expression of the protein PTRF. The loss of caveolae may be associated with increased cell proliferation. This research attempted to reduce PTRF expression using SiRNA in the normal prostate cell line PNTI A to see if this affected cell proliferation. Whilst a reduction in PTRF expression occurred in hormone-treated PNT1A cells, a consistent reduction of PTRF in untreated cells was not achieved. No effect on cell proliferation was observed. Further studies are required to optimise the SiRNA treatment.
A genomic approach to molecular genetics is one that studies all of the genes and RNA in a cell using the latest sequencing and microarray technology. This approach has been extensively applied in cancer research generating a large repository of genome sequence and gene expression data. The limiting factor for this approach to yield clinically relevant information is bioinformatics: statistical and computational analysis of very large datasets. This summer research project aimed to find clinically relevant conclusions from gene expression and methylation datasets in colorectal cancers. Colorectal cancer gene expression data generated by The Cancer Genome Atlas project was used for survival analysis of clinical factors, comparison of gene expression and DNA methylation in different tumour stages, and for unsupervised clustering to find molecular subtypes. Gastric cancer gene expression data was used to find potential synthetic lethal interactions with CDHl, replicating the findings from a larger breast cancer dataset.
Previous research suggests that information is stored at synaptic connections in the brain through a Hebbian spike-timing dependent plasticity (STOP) rule. In this rule, the strength of connections between neuronal cells is increased (or decreased) if their firing coincides in time. Here we aimed to explore whether granule cells of the hippocampus can also exhibit a novel form of non-Hebbian learning. We investigated this hypothesis by delivering spikes in the granule cells alone, without associated activity. We found no evidence of this novel learning rule, however we did provide results that may refute earlier findings in the same brain area.
Haemoglobin (Hb) is an essential protein that exists within red blood cells and plays a major role of carrying oxygen within the blood. During surgical operations there is often blood loss, which can result in anaemia leading to a reduction in vitality due to lowered Hb. To solve this, blood can be transfused into the patient to increase the Hb levels within the blood. This research aimed to see whether there was a correlation between the preoperative Hb level of a patient and the requirement for a postoperative blood transfusion and discovered that with increasing Hb
The amount and duration of antigen presentation to dendritic cells dictates the quality of the subsequent immune response as well as preventing tolerance. Nanofibre devices are advantageous to drug delivery as they have defined structure, molecular composition and predictable biodegradation profiles. This project has demonstrated that an electrospun nanofibre device can be used to activate the immune system in vitro against a model antigen and induce effector cell proliferation, an essential step in the activation of the immune system against cancer. This study suggests that electrospun nanofibre devices are amenable for use as antigen delivery systems for cancer immunotherapy
Progressive loss of muscle mass (sarcopenia) is a widespread manifestation of ageing. The precise cause is unknown, but evidence supports motor nerve terminal degradation as a trigger. A protein, Lrp4, has been identified as a synaptic maintenance signal at the mouse neuromuscular junction, so this project investigated whether loss of that signal underpins sarcopenia. Immunohistochemistry and fluorescence microscopy quantified the level of Lrp4 at healthy and degenerating neuromuscular junctions in muscle extracted from an elderly mouse. No significant difference was found between Lrp4 expression at healthy versus degrading synapses which did not support the original hypothesis. However, qualitative assessment of individual synapses indicates potential for future investigation.
Consuming fruits and vegetables are known to reduce the risk of diseases due to the high content of phytochemicals that can act as antioxidant. The purpose of this experiment was to evaluate the effects of processing on antioxidant capacity and bioactive compounds in summer fruits and vegetables grown in Otago and Nelson region. The result revealed that extraction solvent affected antioxidant capacity significantly due to different plant matrix, processing and the complexity of the corresponding phytochemicals. Processing could lead to the formation and release of phytochemical compounds, which could have more antioxidant capacity; but their degradation should also be considered. Moreover, it was found that heating fruits retained more L-ascorbic acid due to the inactivation of enzymes.
Exclusive breastfeeding is recommended for the first six months of life. Breastfeeding problems are a leading cause of breastfeeding cessation; however there is little quantitative evidence of the prevalence and types of breastfeeding problems that occur each month during the first six months of life. The research project described the prevalence of ‘exclusive’ and ‘any’ breastfeeding during the first six months of life, the prevalence of different types of selfreported breastfeeding problems and when they occur month-by-month during the first six months of life, and to investigate whether breastfeeding problems occur in clusters, in a representative sample of 209 Dunedin women.
Prothrombinex complex concentrates (PCCs) are commonly used to reverse the effects of the oral anticoagulant warfarin, in patients who are actively bleeding, or prior to high risk procedures. Prothrombinex-VF is a PCC, which when combined with Vitamin K, offers fast and complete reversal of warfarin. However, reports indicate PCCs may increase the risk of thrombosis. We retrospectively reviewed 121 patients treated with PTX-VF in Dunedin Hospital and found 5.0% of the patients subsequently had a thromboembolic episode within 30 days. The episodes could not be etiologically linked to PTX-VF use due to the presence of other multiple confounding factors such as patient age and co-morbidity.
How does healthy ageing and Parkinson’s disease affect strategic control over the eye fixation reflex?
Past research has shown that both healthy ageing and Parkinson disease (PD) may compromise the ability to strategically control the eye fixation reflex. The current research investigated these possibilities by comparing the performance of patients with PD, healthy age-matched controls and healthy young adults. A fixation offset effect (FOE) paradigm with preparation of voluntary eye movements was performed. The time course of the eye movements was recorded by using an
eye tracker. Both control and PD groups demonstrated a significant cueing effect and a robust modulation of the FOE. Strategic control over the fixation reflex was preserved in the aged and PD groups.
This study investigates a new method to test the function of the small veins just under the skin in the leg. These veins have valves within them that are thought to keep blood moving towards the heart. If these valves stop working people may be more susceptible to developing leg ulcers. We have used traditional ultrasound scanning combined with an injection of a contrast agent that shows up on the scan to image these small veins. The contrast agent only shows in the small veins if their valves are not working. We were able to demonstrate dysfunction of these valves in both healthy people and in those with ulcers. However the test needs to be developed further to be able to see if there is a difference between these two groups
Gout is a form of arthritis most common in Maori and Pacific Island populations. High serum uric acid levels and fructose intake are risk factors for gout. Single nucleotide polymorphisms (SNPs) associated with high serum uric acid levels in the “Atherosclerosis Risk in Communities” population were identified, and the role of sugar sweetened beverage intake as a marker of fructose intake further investigated. The rs7598433 SNP of the glycerol-3-phosphate dehydrogenase 2 (GPD2) gene was identified as being of interest. In a New Zealand population the correlation between fructose intake and serum uric acid was significantly different between rs7598433 genotype groups.
The vestibulo-ocular reflex (VOR) is thought to be normal in patients with Parkinson’s disease (PD). Due to technical limitations only low frequency VORs have previously been tested. Twenty-three patients with PD were compared to age-matched older and young healthy control groups. Older healthy controls showed a trend to a lower VOR gain with a further trend to reduction in the PD group. The trend to a mild reduction in the high frequency VOR gain in older age may be relevant for imbalance in elderly populations and is worthy of further study. High frequency VOR is unlikely to be a reliable biomarker in PD.
The inferior vena cava (IVC), a large vein that drains the lower half of the body, has two major anatomical variants namely the left-sided and double IVC. Four clinical cases were presented in the report to illustrate these variations, and provide novel data on venous dimensions. A systematic review of the recent literature (2000-2011) was conducted focusing on the anatomy, epidemiology and associated pathology of both malformations. These variants are clinically important for three reasons: the potential for misdiagnosis on imaging; technical difficulties during abdominal surgery; and their significance in relation to the clinical management thrombosis and embolism.
The perspectives and practices of New Zealand midwives regarding nutrition recommendations during pregnancy
The New Zealand Ministry of Health recommends supplementation with iodine during pregnancy and lactation but adherence to this guideline is low. Midwives are the preferred source of information for pregnant women however little is known about their opinions on the guidelines. Semi-structured interviews were carried out among Dunedin midwives to explore their opinions, implementation practices, and barriers to adherence. Results showed that midwives were implementing the guideline for iodine, but the majority did not have a good understanding of the supporting evidence behind it. Increased communication and education for incoming guidelines may therefore be beneficial.
This study aimed to investigate the role of two T-helper cell subsets: T regulatory cells (Tregs, FoxP3+) and Th17 cells (IL-17+) in the regulation of the immune response in oral mucosal lichen planus (OMLP) using immunohistochemistry and immunofluorescence. OMLP displayed significantly more FoxP3+ cells and fewer IL-17+ cells than non-specific inflammatory cases. Double-labelled immunofluorescence showed that FoxP3+ cells co-localised with T cells, while the IL-17+ cells did not. These results support the proposition that Tregs are involved in immune control in OMLP, while the role and nature of IL-17+ cells should be further investigated.
The aim of the project was to evaluate the attitudes and responses by General Practitioners (GPs) and patients in Dunedin to the introduction of dabigatran. GPs and patients were interviewed, and a review of patient clinical records was undertaken. Response rate was 78% for patients and 26% for GPs. 83% of GPs had one or more reservations about dabigatran, however patients had a high satisfaction rating. Issues with a low level of reporting of side effects are highlighted, and it was also found that 16% of patients had ceased to take this agent during the study period,
Ischaemic stroke is a leading cause of death in older humans. Recent evidence has emerged suggesting the brain has a coping mechanism named “ischaemic preconditioning” in which short sub-lethal strokes provide neuroprotection against a subsequent lethal stroke. The present study aimed to investigate the mechanisms of a previously established model of “ischaemic preconditioning” using oxygen-glucose deprivation in brain tissue. A preconditioning effect was not found using this model despite numerous methodological trials. Thus, the experiment has highlighted important methodological concerns for developing a clinically appropriate model of ischaemic preconditioning in brain tissue.
Twenty-six eyes were tested for visual acuity in 17 Dunedin ‘Primary Healthcare’ centres (including the Emergency Department) and compared to the Dunedin Hospital Eye Department. Lighting, distance and other variables were also measured. On average 12 centres produced inconsistent visual acuity scores (11 were worse than the Eye Department’s and one was better). This could lead to unnecessary referrals or unfair withdrawal of a driver licence, and poor grading of suitability for surgery. Incorrectly measured visual acuity may also mean loss of independence for the elderly. We conclude that inconsistencies in visual acuity scores are easily modifiable by following lighting and distance standards.
Recognition of the health properties of milk has stimulated interest in the potential medical value of milk whey proteins that are generated as a side-product fraction of cheese manufacture by dairy companies. There is interest in evaluating the protein composition of sheep milk generated by Blue River Dairy for its medical and health value and it is known that sheep milk is beneficial to people allergic to cow’s milk. This project achieved preliminary fractionation and characterisation of whey proteins in sheep milk for subsequent evaluation of the potential to develop health-promoting whey products.
BEOM JUN LEE (Dr Mary Jane Sneyd and Associate Professor Brian Cox, Department of Preventive & Social Medicine)
The mechanism of seasonal variation in cutaneous melanoma incidence is poorly understood. We analysed the characteristics of incident cases of cutaneous melanoma by season of diagnosis in the population of New Zealand from 1996 to 2007. Incident melanoma cases were grouped into one of four seasons by month of diagnosis defined in the study. The incidence rates among the seasons were compared using summer:winter ratios as well as negative binomial regression for several characteristics of melanoma. We found significant seasonal variability in melanoma diagnosis with the highest months from November through to March for both men and women. It is most likely that the phenomenon of seasonality in melanoma incidence is multifactorial including the effects of sunlight as well as behavioural factors that differ between seasons.
Lipoprotein(a) [Lp(a)] is a cholesterol transport molecule found in blood and a risk factor for cardiovascular disease if elevated. Some individuals, however, have virtually no Lp(a) and this is thought to have a genetic basis. In this study we have identified 27 genetic variants within the LPA gene that result in amino acid changes in the glycoprotein component of Lp(a). One particular variant has previously been shown to impair Lp(a) synthesis and another variant shown to result in a complete inability to form Lp(a). Together, these genetic variants could help to explain the lack of Lp(a) in such individuals.
Urate, the molecule that causes gout in humans, causes reduced insulin sensitivity. The aim of the project was to determine the effect of urate on the expression of the glucose transports, GLUT2 and GLUT9, in mouse pancreatic “MIN6” cells. No change in gene expression was seen after urate was administered to the cells for both GLUT2 and GLUT9. Low expression of both genes was observed leading to insufficient evidence to support the claim that urate reduces GLUT2 and does not change GLUT9 expression.
The aim was to define clinical characteristics and behaviour of leukoplakia, the commonest potentially malignant oral lesion, in patients diagnosed histologically with epithelial keratosis (with or without dysplasia) from 1997 to 2006. For cases (565) that fulfilled the inclusion criteria, the male:female ratio was 1.23:1, and the average age was 54 years. Progression to a higher degree of dysplasia was observed in 4/107 (4%) of initially non-dysplastic lesions. Malignant transformation occurred in 5/169 (3%) of lesions; 3 previously diagnosed with mild and 2 with moderate dysplasia. None of the severely dysplastic lesions progressed. The absence of dysplasia in an initial biopsy did not preclude later progression.
Improving the nanoparticle encasing the anticancer drug RL71 and testing its ability to kill breast cancer cells
Triple negative breast cancer (TNBC) is an aggressive subset of breast cancer lacking targeted drug treatments. To effectively deliver the novel drug RL71 to tumours, nanomicelles were constructed. Two micelle constructs were synthesised containing either a low or high concentration of RL71. Both micelle constructs were large enough to provide targeted delivery to tumours. Micelles were highly water soluble and stable, gradually releasing RL71 across 84 hours in conditions that mimicked blood and tumour environments. Micelles with a high RL71 concentration killed TNBC cell lines more efficiently than RL71 alone. Micelles synthesised possess ideal characteristics for further studies in animals.
Third trimester hypoxic-ischaemic (H/l) injury causes a substantial loss of striatal medium-spiny neurons. Neuronal numbers are restored following delayed administration of mesenchymal stem cells (MSCs). A potential source of these new neurons is the adjacent subventricular zone (SVZ). This project investigated the effect of treatment with MSCs on the proliferation of progenitor cells in the SVZ following H/I injury. Ki-67, a specific label of proliferating cells, was utilised. Results demonstrated a decreased number of proliferating cells in the SVZ following treatment. It is proposed that MSCs serve to increase the migration and differentiation of progenitor cells into the striatum.
Calcitonin gene-related peptide (CGRP) is located in many areas throughout the body and has been shown to have a variety of roles. In the spinal cord, studies suggest CORP has a role in the production of neuropathic pain and generation of tolerance towards neuropathic drug treatments. We conducted an experiment to first determine the level of CORP released in the presence of capsaicin. We then determined whether the opioid, DAMGO, could reduce CGRP release in the presence of capsaicin. Results showed that DAMGO had no effect over CGRP release alone or with capsaicin, suggesting opioid receptors in the spinal cord have no control over CGRP release.
Micro-RNAs (miRNA) are a newly identified class of small non-coding RNAs that play an important role in regulation of gene expression. Circulating miRNAs have been found to be highly stable in plasma, which provides a potential role for miRNAs as plasma biomarkers for disease. By comparing the expression of all known miRNAs in patients with varicose veins, with healthy controls, we identified differences in miRNA expression in both the plasma and tissue samples. These miRNAs were associated with vessel wall homeostasis, angiogenesis and inflammation. This is consistent with prior knowledge of varicose vein pathogenesis, and creates the possibility of miRNAs as biomarkers for venous disease
Smoking increases the risk of developing rheumatoid arthritis (RA). Smoking also causes changes to DNA methylation that affects gene expression. Such changes could explain the increased risk of RA. This study investigated expression of F2RL3, a gene hypomethylated by smoking. Subcutaneous nodule and joint synovial tissues were examined from RA patients who smoked or were non-smokers. F2RL3 was expressed in rheumatoid nodule and synovial tissues seemingly independent of smoking. The methylation status of a further 24 inflammation-related genes was compared in rheumatoid synovium from a smoker and non-smoker. The results suggest reduced methylation is a feature in rheumatoid synovium from smokers.