400 results for Undergraduate

  • Isolation and characterization of human dental pulp derived stem cells

    Kang, Isaac (Jinho) (2013)

    Undergraduate thesis
    University of Otago

    Background: Dental caries remains a major public health concern. Dental endodontics (root canal) therapy involves extirpating the dental pulp and replacing with inert materials. For severe tooth decay, it is the only available treatment; however, it fails to restore the biological functions and vitality of the dental tissues and may ultimately leads to tooth loss. To overcome these shortcomings, dental pulp stem cells (DPSCs) are being investigated as a novel prospective approach to regenerate the dental tissue. In this study, we isolated and purified DPSCs and characterized the purified cells. Objectives: The aims of this study were as follows: (i) to rapidly extirpate dental pulp tissues from human third molar teeth under sterile conditions; (ii) to isolate, characterize, and purify a heterogeneous population of DPSCs using mesenchymal stem cell markers; (iii) to determine the ability of DPSCs to differentiate down an odontoblastic lineage. Design: DPSCs were mechanically and chemically isolated from human impacted third molar teeth. Cells were expanded, passaged, and a heterogeneous population of DPSCs isolated using a cloning cylinder. DPSCs were characterized and purified by flow cytometry using the mesenchymal stem cell markers, STRO-1, CD44, and CD146. DPSCs were induced under two different odontogenic conditions comprising different concentrations of beta-glycerophosphate, and dexamethasone. DPSCs were analysed for morphology, proliferation potential, collagen formation, mineralization characteristics, and expression of the dentin-specific markers dentin sialophosphoprotein (DSPP) and dentin matrix protein 1 (DMP-1), using immunohistochemistry. Results: DPSCs were positive for the mesenchymal stem cell markers STRO-1, CD44, and CD146, although two populations of cells showed different levels of STRO-1 expression. Differentiated DPSCs (dDPSCs) demonstrated a significant increase in alkaline phosphatase concentration between days 14 and 21, while a similar increase in collagen deposition, mineralization, and calcification was also observed on day 28. The proliferation rate of dDPSCs decreased with time. Odontoblast characteristics of dDPSCs were observed, with increased expression of the dentin-specific markers DSPP and DMP-1. Conclusions: This investigation demonstrated successful isolation of DPSCs and differentiation of DPSCs down an odontoblastic lineage, indicating that DPSCs represent a promising approval for the regeneration of lost dental tissues.

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  • Epigenetics and Expression of SFRP1 and PPARG and Epigenetic Effects of Glucocorticoids in B-cell Acute Lymphoblastic Leukaemia

    Foster, Timothy John (2014)

    Undergraduate thesis
    University of Otago

    B-cell Acute Lymphoblastic Leukaemia (B-ALL), a cancer of immature B-lymphocytes, is the most common cancer in childhood. This cancer is characterised by widespread abnormalities of DNA methylation, when compared with non-cancerous blood cells. DNA methylation is a chemical modification of the cytosine residues of DNA, and only cytosine residues immediately followed by guanine residues (so called CpG sequences or sites) undergo methylation. Methylation of CpG sites in gene promoter regions leads to non-expression of the methylated gene. DNA methylation abnormalities in cancers (such as B-ALL) have received significant attention over recent years, and have been shown to have significant biological effects in tumour cells, due to abnormal expression of the aberrantly methylated genes. This project aimed to show that the putative tumour suppressor genes, SFRP1 and PPARG, showed increased DNA methylation in B-ALL cells, when compared with normal blood cells and that this was associated with reduced expression of these genes in B-ALL. The methylation of the gene promoters was determined by bisulphite sequencing and gene expression by qRT-PCR. The results showed that PPARG and SFRP1 both show increased methylation in the gene promoter regions of B-ALL cells, when compared with normal blood cells. SFRP1 has previously been shown to show reduced expression in B-ALL and the qRT-PCR results showed that the PPARγ-1 transcript from the PPARG gene showed reduced expression in B-ALL cells, when compared with B-cells from normal blood as well as normal whole blood. Overall, it was concluded, on the basis of these results and others’, that SFRP1 and PPARG show reduced expression compared with normal blood cells, due to promoter methylation in B-ALL. It has also been suggested in the literature that glucocorticoid drugs (analogues to the steroid hormone cortisol) can alter the methylation of CpG sites in individual genes (in non B-ALL cells). This is of interest in the context of B-ALL, as glucocorticoids are well known to be strong anti-leukaemia agents and are used in B-ALL treatment. Glucocorticoids are also known to affect the expression of many genes, an effect that is compatible with changing the DNA methylation of cells. Therefore, this project also aimed to show that the glucocorticoid dexamethasone could induce changes in DNA methylation in many genes within the genomes of B-ALL cells. Multi-gene methylation was measured using the, relatively new, RRBS technique with the NALM-6 human B-ALL cell-line with or without exposure to dexamethasone acting as my model of B-ALL. The results showed a number of methylation changes throughout the genome, with some particularly strong methylation changes observed in the promoter regions of the genes SPINT2, GATA3, IRX5, SOX13, GATM, PDGFA and DOCK10; genes implicated in cancer or in steroid-sensitive metabolism (such as energy metabolism). These results suggest that steroids do indeed alter the DNA methylation of B-ALL cells, which, if these results are replicated, is a novel mode of action of glucocorticoids in B-ALL treatment.

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  • Cranberry Capsules: The efficacy of cranberry capsules in the management of acute radiation cystitis in men with prostate cancer

    Hamilton, Katelin (2014)

    Undergraduate thesis
    University of Otago

    Background: Acute radiation-induced cystitis is a common side effect of radiation therapy (RT) to the pelvis, with up to 40-50% of prostate cancer patients suffering from cystitis to some extent. Acute symptoms can occur within weeks of radiation treatment and include urinary urgency, frequency, dysuria, and hematuria. Currently there is no effective treatment for radiation cystitis. Here, in a double-blinded pilot study, we investigated the effect of standardised cranberry capsules on the extent of radiation-induced cystitis, and how this impacts on quality of life in prostate cancer patients. Methodology: A total of 41 men receiving RT for prostate cancer at the Southern Blood and Cancer Center (SBCC) in Dunedin participated in this trial, which opened in May 2012. The men took one capsule a day during breakfast from their first day of treatment until two weeks after completion of treatment. This took place regardless of which arm they were randomised to. Cranberry capsules contained 72mg of proanthocyanidins (PACs) each and were indistinguishable from placebo capsules. Patients, clinicians and research assistants were blinded to the content of the capsules. Severity of cystitis was assessed using a modified urinary domain of the Expanded Prostate Cancer Index Composite (EPIC) scale. Items included severity of symptoms (pain, blood in urine, leakage, urinary frequency in day and night) use of pads and symptomatic relief (URAL), as well as the effect of these symptoms on daily life. Results: This thesis analysed the results of the first 10 cranberry and 10 control patients who presented with low baseline EPIC scores. The results showed that cranberry capsules seem to decrease certain aspects of radiation cystitis both with regard to physical symptoms and the effect on quality of life. However results in this small cohort did not generally reach statistical significance and limitations of the trial methodology have been recognised. Conclusion: In light of the limitations of this trial and the positive trends in the results, further investigation is warranted. Future research should focus particularly on establishing consistent hydration levels, regulating the use of symptomatic relief and developing improved methods for assessing the level of acute radiation cystitis.

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  • Global sourcing in New Zealand manufacturing firms: A quantitative investigation

    Davidson, Bethany (2003)

    Undergraduate thesis
    University of Otago

    Global sourcing is a resource acquisition strategy that has created much interest in recent years. As firms strive to remain competitive in an increasingly challenging business environment, many have looked for suppliers outside of their home country in order to develop competitive advantages in their domestic markets. Prior research has shown that significant benefits can be gained from the international integration and co-ordination of their purchasing activities. The aim of this dissertation is to investigate the incidence and application of global sourcing in New Zealand manufacturing firms. A review of the literature relating to the philosophy of supply chain management (SCM) provides the foundation for a discussion of global sourcing. The global sourcing literature focuses heavily on foreign countries, particularly the United States of America. This investigation aims to improve the deficiency that exists in this area, by examining global sourcing within a different context. A quantitative research method in the form of a web-based survey was conducted in this investigation. The data that was obtained from the survey was statistically analysed and a number of results were gained. These results were then discussed and reconciled with the literature with the purpose of determining whether they are consistent with what has already been established. Three key findings of this investigation are highlighted. Firstly, the level of global sourcing strategy pursued by New Zealand manufacturing firms is low, which may indicate a limited ability or need to carry out higher, sophisticated levels of global sourcing strategy. Secondly, New Zealand manufacturing firms have been motivated to pursue global sourcing primarily by 'cost reductions / price benefits'. This reflects the extent to which less expensive labour, less restrictive work rules and lower land and facility costs have enticed many to look at global suppliers. Finally, the major barriers that have caused difficulties for New Zealand manufacturing firms in their pursuit of global sourcing have been identified as 'exchange rate fluctuations' and 'longer lead times and lengthened material pipelines'. This reflects the impact that market uncertainties and geographical isolation can have on the ability of firms to successfully pursue global sourcing.

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  • Bone Tissue Engineering: Generation of Autologous Bone from Mesenchymal Stem Cells

    Stace, Edward Thomas (2011)

    Undergraduate thesis
    University of Otago

    Bone tissue engineering is a developing technology with the promise of generating autologous bone grafts from small bone marrow samples. The ability to culture bone tissue from small marrow samples removes many of the problems associated with current autologous bone grafting techniques specifically donor site morbidity, supply and quality bone tissue. Whilst bone tissue engineering is being researched elsewhere, the exciting prospect of bone banking is novel. We see the cryopreservation of cultured bone for use in later life as an intriguing opportunity for people employed in hazardous jobs such as the armed forces and those engaging in potentially traumatic interests like skiing. To begin bone banking research, a successful bone tissue engineering protocol was required. There were three aspects to this work; defining a protocol for isolation of an appropriate cell population, generation of a suitable three dimensional scaffold and design of a perfusion culture system. This thesis examines these three initial aspects. Mesenchymal Stem Cells (MSCs), isolated from rat femoral bone marrow, were expanded and differentiated down the osteoblastic lineage by 28 days culture in a dexamethasone based osteogenic media. Over this osteogenic culture period, cells developed a cuboidal osteoblast-like morphology. Immunohistochemical staining showed these cells increased the expression of the known bone markers; collagen I, osteocalcin, osteopontin, osteonectin and bone sialoprotein. Additionally, osteogenic cultures showed a 200 fold increase in alkaline phosphatase (ALP) concentration. Scanning Electron Microscopy (SEM) showed the deposition of a highly fibrillar matrix surrounding the osteoblast-like cells in osteogenic cultures. Immunohistochemically, this matrix stained positively for collagen I and alizarin red staining showed mineralization of this matrix. Contrastingly, no change in morphology, no extracellular matrix and no increase in ALP concentration were noted in control conditions. For bone tissue culture, a chitosan-hydroxyapatite scaffold was generated through a freeze drying process. Micro Computer Tomography (µCT) and computer analysis showed the mean pore diameter was 228 µm. SEM surface analysis showed the hydroxyapatite distributed evenly within the scaffold. After the scaffold was subjected to degradation and cytotoxicity testing, MSCs were seeded onto cover slips coated in the chitosan-hydroxyapatite scaffold. MSCs were seen to adhere to and proliferate on this scaffold. MSCs were then seeded on to chitosan-hydroxyapatite scaffolds and cultured under perfusion conditions in the designed perfusion culture system. After a 10 day culture period no cells were detected on the scaffold. This is believed to be due to the low initial cell seeding density. This research has shown the successful differentiation of MSCs down the osteoblastic lineage, fabrication of a suitable chitosan-hydroxyapatite material, cell adherence to this scaffold material and development of a perfusion cell culture system. However, further optimisation of the perfusion culture protocol is needed. Successful perfusion culture would then allow experimentation with cryopreserved cultured bone and further investigation of the feasibility of bone banking.

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  • MANUKA HONEY: An Investigation into the Effect of Manuka Honey on Oral Mucositis in Patients Receiving Radiation Therapy to the Head and Neck

    Parsons, Emma Kay (2011)

    Undergraduate thesis
    University of Otago

    Head and neck cancer is the sixth most common type of cancer, with an estimated 650,000 registrations and 350,000 deaths worldwide annually (Parkin et al., 2005). The treatment for these types of cancers is becoming increasingly aggressive with the majority of patients receiving a combination of surgery, radiation therapy and chemotherapy to cure their cancer. Severe oral mucositis is a common side effect of these cytotoxic treatments with 60% of patients receiving radiation therapy and 92% of patients receiving chemoradiation developing it during the course of their treatment (Parulekar et al., 1998; Sonis, 1998; Dodd et al., 2000; Elting et al., 2003). Oral mucositis leads to many secondary complications including severe oral pain, difficulty in eating and swallowing, taste changes, infection, malnutrition and weight loss. Currently, there is no standard form of treatment for oral mucositis with the majority of treatments aimed at palliation of symptoms rather than preventing or treatment oral mucositis itself. The research presented in this thesis investigates the effect of manuka honey on the prevention and treatment of radiation induced oral mucositis in patients receiving radiation therapy and chemoradiation for head and neck cancers at the Palmerston North Oncology Department. The original study was designed as a stage II randomised single blinded trial where patients were randomised into one of two arms. Patients in the control arm were given the standard treatments for oral mucositis in New Zealand including Benzydamine Hydrochloride (HCL), bicarbonate rinses, pain killers and anti-fungals. Patients in the experimental arm were given all standard treatments and were asked to gargle 20mls of undiluted manuka honey three times per day. Patients oral mucositis was scored three times per week, they were weighed once per week and asked to fill out a food and drug diary everyday and a quality of life questionnaire once every fortnight during treatment. Due to poor patient compliance with the undiluted honey this trial was downgraded to a phase I pilot trial investigating the best way to administer manuka honey to treat oral mucositis. This thesis specifically reports the results for twelve patients recruited to this trial between March 2009 and December 2009. Due to the early downgrading of this trial from a randomised phase II trial to a pilot trial the effects of pure undiluted manuka honey on radiation induced oral mucositis could not be assessed. There was no statistically significant difference in the severity of oral mucositis reported between those taking diluted manuka honey and those using standard forms of treatment only. Patients taking diluted manuka honey appeared to have slightly less weight loss than those receiving standard treatments alone however this did not reach statistical significance. All patients, irrespective of whether they were taking honey or not, reported a severe decrease in quality of life throughout the course of their radiation therapy. There were large issues with patient compliance in this trial. Even when the honey had been diluted significantly patients complained the honey tasted too sweet, made them feel nauseous and stung their oral mucosa. Due to these issues with compliance, it was not deemed ethical to continue with the current trial unless the honey is given to patients is a way which is tolerated better.

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  • Effect of Delayed Treatment with Mesenchymal Stem Cells on Neonatal Hypoxic/Ischemic Brain Injury: A Behavioral and Stereological Study

    Alwakeel, Amr J. (2011)

    Undergraduate thesis
    University of Otago

    Hypoxia/ischemia is a major cause of acute neonatal brain injury and may lead to the development of neurological disabilities, mainly cerebral palsy. Hypoxic/ischemic (H/I) injury occurs as a result of decreased oxygen level in the brain and/or blood and reduced perfusion of the brain tissue. One of the main sites involved in neonatal H/I brain injury is the striatum. In children, injury to the striatum results in the muscular abnormalities of cerebral palsy. Medium-spiny neurons constitute the major neuronal population of the striatum in both primates and rodents. Hence, the rescue or restoration of the medium-spiny neuron population is a viable aim in treating neonatal H/I injury. Current evidence has shown hypothermia, a neuroprotective strategy, to be effective in treating H/I injury. However, hypothermia and other neuroprotective strategies can only be administered within 2 – 6 hours post-injury. The aim of this study was to investigate the therapeutic potential of a seven-day delay in treatment with mesenchymal stem cells (MSCs), a neurorestorative strategy, following hypoxia/ischemia in the neonatal rat. Furthermore, the effect of a subcutaneous injection of a high-dose (HD, 7.5 x 10^5 – 1 x 10^6) and of a low-dose (LD, 8.5 x 10^4 – 1.2 x 10^5) of MSCs was investigated. This was the first study to assess the efficacy of the subcutaneous route of delivery in mesenchymal stem cell (MSC) therapy following neonatal H/I injury. On postnatal day (PN) 7, male pups were exposed to H/I injury. After a seven-day delay (i.e. PN 14), pups were weight-matched in pairs or triplets and randomly assigned to either a diluent injection of Dulbecco's phosphate-buffered saline (DPBS) or a MSC injection. In the LD MSC experiment, five pups were administered the diluent while six pups received a LD MSC injection. In the HD MSC experiment, seven pups were administered the diluent while nine pups received a HD MSC injection. The therapeutic effect was assessed using behavioral testing, and stereological analysis of the absolute total number of striatal medium-spiny neurons. On PN 20, the functional outcome was assessed using the negative geotaxis, cylinder, elevated body swing and foot-fault tests. Each pup was sacrificed on PN 21 and their brain was dissected from the cranium. Injured hemispheres were subsequently embedded in Technovit, serially sectioned and stained. Sections were stereologically analyzed using the Cavalieri method and optical disector method to estimate the absolute number of striatal medium-spiny neurons between diluent- and MSC-receiving pups. To our knowledge, this was the first study that used unbiased modern stereological methods to quantify the absolute number of medium-spiny neurons in the striatum following MSC therapy in neonatal hypoxia/ischemia. A sub-aim of this study was to determine the efficacy of the negative geotaxis test in the study of neonatal H/I injury before the administration of any treatments. As such, pups were tested on the negative geotaxis apparatus on PN 12 and PN 14, prior to MSC and diluent injections on the afternoon of PN 14. The findings of this study showed that a seven-day delay in MSC treatment did not have a statistically significant improvement on the functional outcome following H/I injury. However, a positive trend was observed in the cylinder test in pups receiving MSCs. MSC administration resulted in a higher preference of using the contralateral injured limb over the ipsilateral uninjured limb when compared to the diluent-administered pups. This positive trend was more profound in the HD MSC group compared to the LD MSC pups. The stereological findings showed that delayed MSC therapy was effective in attenuating the loss in striatal medium-spiny neurons compared to diluent-receiving pups. This difference was found to be statistically significant. The HD MSCs were more effective than the LD MSCs and restored the number of striatal medium-spiny neurons to normal levels. The subcutaneous route was also shown to be an effective route in delivering MSCs. Finally, results from the negative geotaxis test showed that this test may not be an effective assessment in evaluating the functional outcome following neonatal H/I brain injury. In conclusion, the findings of this study suggest that delayed MSC therapy can be an effective tool in treating neonatal H/I brain injury. These findings may offer hope to children who have missed the critical period of 2 – 6 hours post-injury, which is limited to neuroprotective interventions.

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  • Measuring the Physical Activity of Children aged 3 to 7 years

    Ku, Hsi-Yu (2011)

    Undergraduate thesis
    University of Otago

    Introduction : Obesity has become epidemic throughout the world and is affecting both adults and children. New Zealand children have a high prevalence of being overweight, with estimates varying between 20% and 30%. Sedentary behaviour (SB) is an important mediator of successful prevention of developing overweight in children. However a reliable objective method for measuring SB is still lacking. Effective prevention of excessive weight gain could flow from having an objective device with a clear definition of SB. Accelerometers are motion sensing devices which have been used to study physical activity (PA) with promising validity in children. As one of the steps in establishing the utility of accelerometers in measuring SB, we aimed to assess the reliability and validity of the Actical accelerometer for its use in 3-7 year old children and to propose an appropriate cut-off that defines SB. Methods : Children (N=50) aged 3-7 year old were recruited in Dunedin, New Zealand, to participate in the study. The study was carried out at the participants’ preschool centre or school. The children were asked to wear the Actical accelerometer around their waist and to perform numerous selected activities of varying levels of intensity. At the same time, participants were video recorded for observational analysis to provide the criterion measure of PA. Activities performed during free play sessions at participants’ preschool centre or school were also measured. Reliability of the Actical accelerometers was assessed daily throughout the data collection phase using a custom-made motion generator. Validity of the accelerometer was assessed by comparing with activity levels measured by direct observation using the Children’s Activity Rating Score (CARS). The appropriate cut-off to define SB was determined by plotting the receiver operating characteristic curve, and the cut-off derived was then cross-validated by comparing with levels of SB measured by using the CARS. Results : Height, weight and BMI distributions of the children assessed (N=49) were comparable with published data on New Zealand children. Reliability tests during the data collection phase revealed high intra-instrument and inter-instrument reliabilities (r p-intra & r p-inter =1.0). Repeated measurements by the same accelerometer gave small differences (<0.05) and were categorised into four groups: inactivity (Sleep), sedentary level movement (Draw, Play Doh, Puzzle, Read, TV), light level activities (Toy Car), activities of higher intensities (Nintendo Wii and Free Play). Using the receiver operating characteristic curve (area under the curve: 0.843), a cut-off of 40 counts/15s was identified (sensitivity: 88.44% and specificity: 64.63%). For the children assessed by the CARS (N=9), correlation between Actical counts and CARS score was moderate (r p =0.56). The mean difference of percentage of time in sedentary activity judged by accelerometry compared to direct observation using CARS was 8.4%. There were no significant differences in the percentages of sedentary activity between accelerometer data versus CARS (p=0.055). Conclusions : Overall, the study has proposed a cut-off for SB of 40 counts/15s. Despite having obtained moderate correlation with the criterion measure, it appears that this cut-off tends to slightly under predict levels of SB and accurate prediction of SB is limited by sub-optimal inter-instrument agreement. Performance of the Actical could be improved if accurate calibration were possible outside the manufacturer. Utility of the cut-off could be further assessed by conducting a cross-validation of the cut-off with a larger sized sample. Outcome : The results of this study could be used in ongoing studies that use the Actical accelerometers to measure activity in children aged 3 to 7 years.

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  • Prolactin Regulation of Kisspeptin Neurons

    Crampton, Jessica Rose (2011)

    Undergraduate thesis
    University of Otago

    It is well established in both humans and rodents that the state of hyperprolactinaemia leads to reduced reproductive capacity, as a consequence of suppressed luteinising hormone secretion. Return of reproductive function can be achieved by physiological gonadotropin-releasing hormone (GnRH) administration in humans. In rodents, there is no decrease in pituitary GnRH responsiveness in the presence of elevated prolactin. These findings indicate that prolactin, an anterior pituitary hormone capable of direct action in the central nervous system, is affecting hypothalamic GnRH secretion, rather than pituitary gonadotropin secretion. However, as prolactin receptors are only expressed on a small minority of GnRH neurons, a direct suppressive action by prolactin on these neurons is unlikely. Hence, an indirect mechanism utilising neurons afferent to GnRH neurons may be in place. The neuropeptide kisspeptin has recently been discovered to be a key afferent regulator of GnRH secretion. Prolactin receptors are present on the majority of kisspeptin neurons, leading to the hypothesis of this thesis; that prolactin inhibits kisspeptin neurons, providing an indirect pathway through which prolactin alters GnRH output. To investigate this hypothesis, several experiments were carried out. Firstly, double-label immunohistochemistry, staining for pSTAT5 (an intracellular signal transducer of prolactin signalling) and kisspeptin, was performed throughout the AVPV/PeN and arcuate nuclei of the rat hypothalamus. Colocalisation of pSTAT5 nuclear-staining within kisspeptin neurons was evident in ovine prolactin (oPRL)-treated animals, indicating that the prolactin receptors expressed by kisspeptin neurons are functional in vivo. Secondly, Kiss1 mRNA expression in a lactational model of hyperprolactinaemia was analysed by qPCR. There was a significant suppression of Kiss1 mRNA expression in each nucleus during lactation compared to diestrous levels. This was not reversed by prolactin removal (by bromocriptine-treatment), suggesting a suckling-induced suppression not mediated solely by prolactin. A third treatment group, where pups were removed and oPRL was administered, however, suggested the presence of an additional suppressive effect of prolactin in the arcuate nucleus. Finally, in order to investigate the effects of hyperprolactinaemia without the confounding factors of a lactation, a nonlactational model of chronic hyperprolactinaemia was developed. This trial involved ovariectomy with low level oestradiol replacement, and oPRL administration every 8 hours for 48 hours. Serum oPRL concentration, profiled by serial blood sampling through indwelling jugular cannulae, was found to peak 1 -3 h post-injection (approximately 80 ng/ml) and drop to 0 ng/ml by 6 h post-injection. This oPRL-treatment did not suppress LH concentrations compared to vehicle-treated controls, and thus in this regard, the model was unsuccessful. Nevertheless, the hypothalamic tissue obtained was analysed by qPCR to investigate whether Kiss1 mRNA expression was altered by oPRL-treatment. No significant changes were detected in the AVPV/PeN, whilst in the arcuate, there was a significant four-fold increase in Kiss1 mRNA expression in vehicle-treated, ovariectomised rats. This increase was significantly dampened by approximately half, in oPRL-treated ovariectomised rats. Each of these experiments provide evidence in support of the hypothesis; indicating that prolactin does regulate kisspeptin neurons. This finding could hold important implications for further investigations into the use of kisspeptin as treatment of hyperprolactinaemic infertility, a condition that hinders many patients.

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  • Bowel Bacteria and Dendritic Cells in Ankylosing Spondylitis

    Peyroux, Estelle (2011)

    Undergraduate thesis
    University of Otago

    Ankylosing Spondylitis (AS) is chronic inflammatory arthritis of spine and sacroiliac joints with further peripheral manifestations. AS is a relatively common rheumatic disease affecting 0.1- 1.4% of the population. Early symptoms commence generally in the second decade of life, these include fatigue and pain which are managed by adherence to medication. Inflammation can result in fusion of the vertebrae in the spine. Susceptibility genes identified encode HLA-B27 and ERAP1 proteins, both essential components in antigen processing for immune response. An animal model of AS induced by the hla-B27 gene (present in 95% AS patients) indicated enteric bacteria triggers AS-like symptoms. Dendritic cells (DCs) are professional antigen presenting cells that direct immune responses. We generated monocyte-derived DCs (MoDCs) from venous blood of AS (n= 6) and control group (n= 8) and stimulated the cells with a range of gut bacteria- Bacteroides fragilis, Yersinia enterocolitica, Campylobacter jejuni and Helicobacter pylori. We measured expression of antigen presentation molecules MHC-I and MHC-II and CD83, a marker of activated DCs, by flow cytometry. Analysis of cytokine secretion in supernatants was assessed by Bioplex immunoassay. In addition to this preliminary experiments with inhibitors to MyD88 and TRIF adaptor molecules were used to identify the possible involvement of toll-like receptors in activation of DCs to bacterial treatments. The AS donors had a trend of lower basal expression of MHC-I and MHC-II. Our results indicated the level of MHC-I and MHC-II expression is significantly different (p< 0.0001) between AS and normal groups. The normal group’s up-regulation of MHC-I in response to C. jejuni was significantly greater (p= 0.03) compared to the AS group (p=0.1). Differences in MHC-II expression between AS and normal groups were just outside significance levels (p= 0.08) for both B. fragilis CAS10 and H. pylori treatments. CD83, a DC maturation marker, was expressed at similar levels for all AS-associated bacteria. H. pylori induced CD83 expression significantly (p= 0.03) in the normal group however the AS group did not up-regulate CD83 expression significantly (p= 0.2). Cytokine analysis showed a trend of decreased IL-12 and IL-10 production in AS-associated bacteria particularly in B. fragilis CAS10 and Y. enterocolitica. Our control bacteria, H. pylori, inversely induced higher IL-1β, IL-10 and IL-12. From these results we hypothesize that abnormal signaling through innate pattern recognition receptor signaling pathways induces aberrant activation of DCs in AS patients. These DCs in turn may direct cells of the immune system toward an inappropriate or misdirected immune response. We speculate that a low IL-10 production by DCs may result in a dysregulation of the immune response.

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  • The actions of Activin C and its mechanism towards the progression of Prostate disease

    Lee, Kai Lun (2011)

    Undergraduate thesis
    University of Otago

    The Transforming Growth Factor β (TGF β) superfamily is involved with regulating many biological and physiological processes. Activins are members of the TGF β superfamily. Four activin subunits (βA, βB, βC and βE) have been characterized in mammalian cells. Activin A is a negative growth regulator in the prostate and dysregulation is associated with prostate disease. Activin βC was discovered only in the last decade. Recently it was shown that activin βC regulated the expression and bioactivity of activin A, and over-expression led to the development of prostate disease in mice aged 3 months. The current study hypothesized that activin βC functions locally to antagonize the activity of activin A, and over expression of activin βC can therefore lead to the formation of overt prostate disease in aged mice. We used overexpressing activin βC transgenic mice (TG) aged 12 months, and studied the dorsal and ventral prostate. There were clear signs of hyperplasia in the TG prostate epithelial cells, and some abnormally stained nuclei indicative of mucinous metaplasia. The prostate weights had also increased due to a significant increase in epithelial cells. Immunohistochemistry was then performed for PCNA and the results indicated no increase in cellular proliferation. However, a decrease in apoptosis was also evident as was a decrease in p-SMAD 2 signaling in the dorsal prostate. Thus supporting our hypothesis that increased activin βC antagonized the growth inhibitory effects of activin A and this was the mechanism underlying the alterations in proliferation and apoptosis. Pathway focused gene expression was then undertaken in the dorsal prostate to assess the mechanism by which over-expression of activin βC decreased proliferation, apoptosis, and SMAD 2 signaling. An increase in gene expression of activin βA and βB, the activin receptors, as well as the SMAD signaling molecules were evident. In addition, an increase expression of gene in the negative regulation of cell cycle was observed in TG samples, indicating that these cells were signaled for growth arrest. This validates the decreased PCNA and apoptosis data in the TG prostate sections. Finally, correlation with human prostate pathology was determined by assessing the staining of activin βA and activin βC in human prostate disease arrays. Activin βA was increased in all prostate disease whereas activin βC was only increased in benign prostatic hyperplasia. Therefore we conclude that activin C is associated with benign disease and not prostate cancer in mice and men.

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  • The Hamstring Muscles: Proximal Musculotendinous Junctions

    Storey, Richard Norman (2012)

    Undergraduate thesis
    University of Otago

    Background: Acute hamstring strains are common injuries in sports, responsible for excluding athletes for a considerable amount of time from participation and competition. This places a substantial burden on professional sporting organisations and healthcare systems. Aims: To describe patterns in the site and mechanism of hamstring strains and examine the morphology of the proximal tendon and musculotendinous junctions (MTJs) of these muscles using dissection and magnetic resonance imaging (MRI). Methods: Two systematic literature reviews were undertaken, firstly to ascertain the site and mechanism of hamstring strains in the medical imaging literature and secondly to review the anatomy of the hamstring muscles relevant to acute strains. The morphology of the proximal MTJs of biceps femoris long head (BFlh), semitendinosus (ST), and semimembranosus (SM) was investigated using two methods: (i) individual muscles in ten thighs from five male cadavers (aged 64-85 years) were dissected and measured in situ and then resected, embedded in jelly and serially sectioned for scaled photography; (ii) the hamstring muscles of 11 physically active men (aged 18-30 years) were imaged bilaterally using MRI. In each study group, the length, volume and cross-sectional area of the proximal tendon and muscle belly were measured. In addition, novel measurements of the muscle-tendon interface area at the proximal MTJs were taken in cadavers and the MTJs in both groups were reconstructed three-dimensionally (3-D) using Amira 4 software. The relative force of muscle contraction at the proximal MTJ was estimated by calculating a muscle belly volume to muscle-tendon interface area ratio. Comparisons were made between the three hamstring muscles and between study groups. Results: The literature review of hamstring strains indicated that the most frequently injured hamstring muscle is BFlh (65.8% of all acute strains). The MTJ was the site of injury in 73% of strains, usually the proximal MTJ. The site and mechanism of hamstring strains appear to be related: powerful eccentric contraction as occurs in sprinting is commonly associated with BFlh strains with or without additional pathology in ST, and, slow-speed stretching injuries predominantly affect SM but can also involve adjacent muscles such as quadratus femoris. Review of the anatomical literature showed that the morphology of these proximal structures is not well understood. Three-dimensional reconstruction showed a similar proximal tendon and MTJ morphology in elderly cadavers and young active men. In both groups SM consistently had the longest proximal tendon in all specimens and, on average, MTJ, the latter extending over 20 cm2 in both groups. In cadavers the MTJ of SM also had the greatest muscle-tendon interface area (84.6 ±31.5 cm2). Muscle belly volume was more than three times greater in young active men than in elderly male cadavers. Muscle belly volume/MTJ interface area ratios suggested that BFlh experiences the greatest forces at its proximal MTJ, with a ratio of 1.68, compared to 1.65 for the proximal region of ST, and 1.24 for SM. ST muscle fibres inserted proximally into both the common proximal tendon of BFlh and directly into the ischial tuberosity. The hierarchy of hamstring muscle peak cross-sectional area varied among the young active men but was constant in elderly cadavers. Conclusions: These results suggest that the morphology of the proximal MTJ is relatively consistent. However, key differences were evident between hamstring muscles. Estimation of force transfer at the proximal MTJ suggests that the architecture of the proximal MTJ in BFlh and ST may render them vulnerable to acute strains during powerful muscle contraction. In contrast, the larger muscle-tendon interface found in SM suggests less concentration of force at the MTJ and its longer proximal free tendon may explain its vulnerability to slow speed stretching injuries.

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  • Corporate culture as normative control: A study of Hong Kong employees in a team-based organisation

    Lo, Wattle C W (2000)

    Undergraduate thesis
    University of Otago

    Corporate culture is a form of normative control (Fleming & Stablein, 1999; Kunda, 1992). Normative control can be described as a system of control that "works internally by engendering people with subjective attributes and dispositions, which are compatible with the maintenance of certain types of work organisation" (Fleming & Stablein, 1999:3). Since the early period of capitalist mode of production, corporate managers have been searching for effective techniques to control their workplace activities. Over the past two centuries, corporate control strategy had been changing according to economic conditions, technology, culture, and business nature. Edwards (1979) in his book Contested Terrain suggested that many large corporations had shifted their strategy from the simple forms of control to technical, and gradually bureaucratic administration, as a result of the growing need for efficiency and productivity (Barley & Kunda, 1992; Edwards, 1979). The use of assembly lines, cost accounting systems, and bureaucratic rules — in short, the utilitarian forms of control — were the key principles of organising production from 1900 to the 1930 (Barley & Kunda, 1992). Culture as a form of control strategy remained unfamiliar to many management scholars and practitioners until the late 1970s. Influenced by anthropology and sociology, corporate culture came to prominence in 1980, and entered into managerial discourse (Barley & Kunda, 1992). Thereafter, managerial interest in building corporate cultures caused a proliferation of organisation literature ranging broadly from popular business magazines to commercial management books (Barley & Kunda, 1992). Famous writers, such as Peters and Waterman (1982), Deal and Kennedy (1982), and Ouchi (1981), excitedly urged business managers to cultivate strong corporate cultures that harness loyal, committed, and hardworking employees (Barley & Kunda, 1992). They criticised that traditional forms of corporate control will eventually eliminate certain human attributes – for example, commitment, flexibility, creativity etc. – that are crucial for enhancing business performance in a fast-changing environment (Barley & Kunda, 1992). In In Search of Excellence, Peters and Waterman advised, "all that stuff you have been dismissing for so long as the intractable, irrational, intuitive, informal organisation can be managed" (Peters & Waterman, 1981:11). They argued that corporate cultures, which centre on principles such as cultivating workplace values, employee motivation, autonomy, organisational commitment, and team building, are the key to success in contemporary business (Peters & Waterman, 1982). Corporate culture is increasingly recognised as an important means of controlling workplace activities. The gain in popularity of cultural management' in recent decades has marked the point of departure from classical to contemporary management philosophy. As a novice researcher, my interest in corporate culture stems from two propositions. First, corporate culture as a form of normative control is amazingly effective for promoting teamwork2 in organisations. Proponents argue that culture building cultivates a shared meaning and purpose among team members (Fleming & Stablein, 1999), harnessing their commitment and energy towards efficiency and productivity. As a result, members are more willing to share their experience and knowledge with their counterparts, facilitating cooperation and mutual accountability (Cadwell, 1997). Promoting teamwork requires the manipulation of team values, norms, and beliefs, so that members become much more loyal and devoted to the team and organisation (Fleming & Stablein, 1999). This manipulation is achieved through designing workplace activities, ranging from daily communications to corporate meetings, training sessions, and peer gatherings. Managers design the ways in which these activities are performed and employees are responsible for the maintenance of those activities (Cadwell, 1997). They learn about team values through their participation in socialising with others. Once members have internalised these values, they come to discipline themselves in teams without the need for managerial control. Second, my interest in corporate culture also lies in the premise that this form of control is not as perfect as it has been generally envisaged. Although corporate culture is effective in fostering team spirit in organisations, members nonetheless experience intense peer pressure among themselves (Ezzamel & Willmott, 1998). Not only are members under constant supervision by their counterparts, but also are required to actively monitor their own team performance (Ezzamel & Willmott, 1998). Peer competition is intense. Some opponents, such as Kunda (1992) and Casey (1995), argued that team members, in fact, do not gain a sense of empowerment, ownership, and participation. Rather, they often experience negative emotions such as ambivalence, anxiety, fear, and pressure (Kunda, 1992; Casey, 1995). Further, employees' resistance to managerial practices of team building is a common phenomenon in the contemporary workplace (Collinson, 1994). Depending on different situations, the intensity of their resistance can range from a simple tactic of indifference to an active endeavour of manipulating critical information (Collinson, 1994). These issues challenge the utopian presuppositions of a team culture, and raise doubts about its effectiveness as a form of normative control. The two stories above have evoked my desire for thinking about team building in the context of Hong Kong — a place in which I grew up. As most current research on team culture is primarily conducted in large corporations in the U.S., such bias further stimulates my interest in finding out how Western knowledge may be applied to understanding Hong Kong people in the workplace. This is perhaps also due to the fact that I, as a research student from Hong Kong, recognise some irreducible differences between Western and Chinese cultures. Of course, these cultural differences cannot be simply reduced to a simple distinction between East and West. As it is well known, Hong Kong was a British colony with strong Chinese characteristics (which I will discuss in the second chapter). This uniqueness of Hong Kong raises questions about the typical Western view on the implications of a team culture for the employee. It forces me to ask: if Hong Kong is presumably neither a Western nor Chinese city, what are the likely problems when trying to make sense of the employee based on Western assumptions? Does a team culture have the same effects on the Hong Kong employee as those on the American? Is Western management knowledge universally applicable to every culture context? I attempt to address these questions by studying one of the branch offices of a leading British Insurance company in Hong Kong. My research study specifically focuses on both Quality Assurance and Corporate Culture as Normative Control Human Resource departments. The Quality Assurance department has a particular emphasis on teamwork, and is run by four Hong Kong staff. Three other employees of the Human Resource department are included in my study. They are the people who actively promote teamwork in the organisation. For convenience, I will call the Hong Kong branch office "ABI", the Quality Assurance department "QA", and the Human Resource department "HR".

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  • International trade and employment in French and West German manufacturing industries

    Chetwin, William (2000-10-09)

    Undergraduate thesis
    University of Otago

    The debate over the implications of international trade for the labour market is a prominent one both among economists and the general population. Because of that fact, and because of the absence of a comprehensive economic theory that explains the implications of trade for labour, empirical study is needed to provide a basis for the development of theory and to provide an objective basis for making policy decisions. This study aims to fill a gap in the literature by studying each of eight manufacturing industries individually, rather than pooling these together into an aggregate study as is the case in much previous work. Using data on two-digit ISIC (International Standardized Industrial Classification) manufacturing industries in France and West-Germany for the period 1970-1991, it estimates a labour demand equation for each of the eight industries and includes indicators of trade as explanatory variables. The first of the two main conclusions is that trade appears to have an effect on employment over and above its indirect effects through output, wages, and other variables. The second main conclusion is that this effect differs across industries. The implication of these conclusions is that previous studies which pool disaggregate data to look at the manufacturing industry in the aggregate may fail to provide important information about how individual industries adjust. This means that their predictions may not provide useful information on the partial equilibrium effects of trade and trade policy, and because they say little about how firms or industries adjust they do not provide useful information for the development of further theory in this area. The overall implication of this study is that more work should be carried out to ascertain the effects of trade on the labour market at a disaggregate level. Recommendations are made regarding the issues to be considered in undertaking further study in this area, and regarding approaches that should be taken in order to provide information for the development of theory, and in order to obtain results that improve the information sets of policy makers.

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  • Recombinant Virus-Like Particles Presenting Epitopes for Antibody Generation

    McCulloch, Tim (2012)

    Undergraduate thesis
    University of Otago

    Virus-like particles (VLP) have been shown to be effective vessels for drug or gene delivery, and vaccination. Much research has focused on the generation of VLP carrying heterologous tumour antigens to initiate cell-mediated immunity against tumours, where the VLP enhances the immunogenicity of the attached antigen. However, VLP can also be modified to incorporate an antigen on the surface to facilitate antibody generation. Purification tags or specific coupling sites could also be incorporated onto the surface of the particles, improving their functionality. This study aimed to utilise the immune stimulatory properties of VLP to generate antibodies against a heterologous model antigen, producing a scaffold for delivery and enhancement of antibody mediated subunit vaccines. More specifically, Human Norovirus (HuNV) and Rabbit hemorrhagic disease virus (RHDV) capsid proteins were engineered to express the YG1 epitope from human tumour necrosis factor-alpha (hTNF-α) at positions predicted to be displayed on the surface of the VLP. Amino acids positions 368 of HuNV and 306 of RHDV capsid proteins were identified in the literature as confirmed sites of peptide insertion, with each locating to the exposed loops of the capsid protein P domain. Recombinant gene constructs expressing the YG1 peptide at these sites were produced by PCR. VLP were expressed in a baculovirus expression system and purified using differential centrifugation and cesium chloride gradient separation. Following expression, recombinant VLP assembly was confirmed by electron microscopy, and while the RHDV VLP was less stable than HuNV, they were both able to form particles. Rats immunised with these recombinant VLP generated IgA and IgG antibodies specific for both the native VLP carrier and the YG1 epitope. Thus initial data indicates that HuNV and RHDV VLP can be genetically engineered to act as vaccine delivery systems, leading to enhanced peptide based subunit vaccines. The confirmed insertion sites could also be used to incorporate purification tags, specific coupling sites, or allow multi-epitope capability, where peptides can be included at both the N-terminus and on the surface of the same VLP.

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  • Allocation and Ageism in Aotearoa: An exploration of the ethical justification for age-based healthcare rationing

    Lambie, Deborah (2013)

    Undergraduate thesis
    University of Otago

    New Zealand’s population, like many first world countries, is ‘ageing’. This will place our healthcare system under increasing and changing pressures, as there will be a greater proportion of older people in our population who have particular health needs and generally require greater levels of care over longer periods. These projected changes have resulted in calls to ration healthcare resources to the elderly. This is driven in part by concerns that the elderly will consume resources at the expense of other generations. Such proposals have been met with staunch criticism, most of which focuses on the idea that age-based allocation devalues those discriminated against, viz. the elderly. In this thesis I argue that this criticism can theoretically be overcome if the principles of age prioritisation are applied consistently over the lifetime of members of society, so that everyone is equally affected. I then introduce Norman Daniels’ ‘Prudential Lifespan Account’, which provides a moral basis from which such principles can be derived. This shows us that as a society we should protect the ‘normal range of opportunity’ available to citizens. This creates a need for resources to be distributed fairly between generations in order to ensure that each is given the best chance possible of having the normal range of opportunity. Under this theory, certain forms of age-based allocation can be justified. I go on to outline Daniel Callahan’s view of the nature of mortality and end-of-life care, which incorporates Daniels’ Prudential Lifespan Account. This provides a helpful framework for reflecting on our collective response to ageing and dying, which will place certain limits on the amount spent on care for the elderly. However, these limits will not ultimately address the challenges our healthcare sector is currently facing due to the ageing population. With this in mind, I consider whether a straightforward cut-off for healthcare allocation is ethically justifiable. I argue that it cannot because it contradicts the basic principles of justice underpinning Norman Daniels’ theory, and so lacks an adequate moral foundation. Some other responses must be taken in order to ensure that members of our society receive their share of opportunity. In the final chapter I outline some possible strategies that are consistent with the ideals put forward by both Daniels and Callahan.

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  • CT Investigation of Thoracic Intervertebral Disc Morphometry

    Fletcher, Justin Geoffrey Revell (2013)

    Undergraduate thesis
    University of Otago

    Background: Despite being prone to degenerative disease and other pathology, relatively little is known of the morphology and morphometry of thoracic intervertebral discs in comparison to discs in the cervical and lumbar spines. The few studies of thoracic intervertebral disc morphometry that have been performed have included relatively small numbers of cadavers. No previous studies have attempted to investigate how thoracic intervertebral disc morphometry varies with sex and age. Aims: This study aimed to describe the normal morphometry of adult thoracic intervertebral discs in subjects with no known spinal disease and investigate potential associations with sex, disc level and age. Methods: Computed tomography (CT) scans on 128 recently deceased unembalmed cadavers (70 males, 58 females, aged 20-79 years, divided into 10-year age cohorts) with no known spinal pathology were obtained from the archives of the Victorian Institute of Forensic Medicine, Australia. Intervertebral disc height, anteroposterior and transverse disc dimensions, wedge-index and other morphometric parameters were measured at alternate intervertebral discs throughout the thoracic spine, beginning at T2-3. Data were analysed to determine associations between intervertebral disc parameters and sex, disc level and age (10-year age groups). Linear mixed models were fitted to anterior and posterior disc height and anteroposterior and transverse disc dimensions. Intra- and inter-rater variation were assessed by intraclass correlation coefficients (ICCs) performed on 25% and 18% of the whole sample, respectively. Measurement reliability was further assessed by investigating agreement between radiographic and equivalent measures performed directly on two cadaver thoracic spine specimens. Results: Intervertebral disc heights and axial dimensions were all significantly larger in males than females except middle disc height (anterior disc height 4.0 ± 1.4mm vs 3.6 ± 1.3mm; posterior disc height 3.6 ± 0.90 vs 3.4 ± 0.93, both p<0.05). Discs in the upper and lower thoracic spine were significantly more wedge-shaped and displayed greater convexity than those in the mid-thoracic spine (T6-7). Except at T2-3, anterior disc height decreased with advancing age while anteroposterior and transverse disc dimensions increased; posterior and middle disc heights and indices of disc shape showed no consistent statistically significant change. Most measured parameters showed substantial to almost perfect agreement for both intra-rater and inter-rater reliability while cadaver validation showed fair to almost perfect agreement between radiographic and anatomic measures. Conclusions: Thoracic intervertebral disc morphometry varies significantly and consistently with sex, disc level and age. This study provides unique data on normal thoracic intervertebral disc morphometry of adults, which should be useful in the detection of pathological changes and for informing biomechanical and functional studies.

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  • Brain Regions Responding to Endogenous Prolactin during Pregnancy and Lactation

    McFadden, Sarah Louise (2013)

    Undergraduate thesis
    University of Otago

    There is an increased incidence of dysfunctional mood disorders postpartum, affecting approximately 10-20% of all women. Postpartum mood disorders can have devastating effects on the mother, and lead to altered relationships with offspring, an increased incidence of child abuse, and increased conflict in relationships leading to a higher rate of separation. It has been discovered that low levels of prolactin during early pregnancy prevent the normal increase in neurogenesis in the subventricular zone (SVZ) from occurring, resulting in markedly increased anxiety postpartum in mice. However, it has been observed that the SVZ does not express prolactin receptor mRNA, nor prolactin-induced phosphorylation of the transcription factor STAT5 (pSTAT5), a marker of prolactin mediated signal transduction. Therefore, we hypothesized that the normal elevation of prolactin that occurs in early pregnancy initiates changes in other areas of the maternal brain that indirectly lead to increased neurogenesis in the SVZ. The aim of this study was to characterize which areas of the brain are activated in response to the normal surges of prolactin that occur during early pregnancy, and also if there is a difference in the regions of the brain that are activated during pregnancy and in the postpartum period. A group of mice were killed on day 3 of pregnancy at a time when prolactin levels were low, and another group of mice were killed during a surge when prolactin levels were high. Two groups of mice were also killed on day 7, one at a time when prolactin was low, and the other when prolactin was high. The final two groups were killed on postpartum day 4; one group had been exposed to pups, and the other had not. Using immunohistochemistry we analyzed levels of pSTAT5 throughout the mouse brain. We found that expression of pSTAT5 was significantly increased when prolactin levels were high compared to when they were low during pregnancy. Expression of pSTAT5 was seen in regions of the brain known to be crucial for regulation of mood and behaviour, such as the medial preoptic area, and also in the Arcuate nucleus and the VMH (ventromedial hypothalamic nucleus). In the lactating mice, a higher expression of pSTAT5 was seen in these areas, as well as in additional areas not seen during pregnancy, such as the Bed Nucleus of the Stria Terminalis, the Amygdala and the Dorsomedial Hypothalamic Nucleus. These areas may be areas necessary for maternal behaviours at the time of lactation. We also stained for c-fos, a marker of early gene activation in neurons to establish if there were nuclei that are indirectly responding to prolactin. The c-fos data showed that it was not a good marker for prolactin activation, but it was able to show areas of the brain important for maternal behaviour. In conclusion, this study confirmed that prolactin does not activate pSTAT5 in the sub ventricular zone during pregnancy, consistent with the hypothesis that prolactin induced increase in neurogenesis in this area is mediated indirectly. We identified the MPA, the arcuate and the VMH as the major areas responsive to endogenous prolactin in early pregnancy. Moreover, we found that there were more prolactin-responsive areas in the maternal brain during lactation.

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  • Investigating and enhancing rural communities’ existing mental health service networks.

    Erskine, Nicholas Robert (2014)

    Undergraduate thesis
    University of Otago

    Mental illness is a growing concern throughout the world. The burden of mental illness is increasing globally, currently representing 7.4% of the total years of life either lost due to premature mortality or lived with disability. In New Zealand, the estimated life-time risk of meeting the criteria for one or more mental illnesses is 46.6%. It is therefore essential to have a secure and effective mental healthcare system throughout the country. This can be particularly challenging to deliver in rural communities due to the unique circumstances that they face. Previous studies have found that rural residents have decreased access to mental health specialist services, and increased exposure to mental health risk factors. However, there is ongoing dispute as to rurality’s overall effects on mental health status. Further research is required. Despite the urgent need to better understand the interactions between rurality and mental health, there is a severe paucity of research in the area on a national and global scale. This action research project helped investigate the impact of rurality on mental health within New Zealand by interviewing mental health and wellbeing service providers operating in Wanaka and Balclutha. The information gathered from these rural providers included their difficulties with interagency collaboration, the effects caused by rural providers working beyond their role descriptions, rural community characteristics that impact on service access, and service deficits within rural communities. This data was used in conjunction with established literature in order to help understand several of the issues that are important to mental healthcare in rural New Zealand communities. From this background, attempts were made to help improve Balclutha’s existing mental health service network. These attempts included facilitating networking between services, creating a community-specific service information package, and encouraging the use of minimal-contact guided self-help therapies in a community-appropriate manner. By investigating issues that are pertinent to rural mental health in New Zealand, this project helps address a major gap in current knowledge. The feasibility testing and process evaluation of enhancing an existing mental health service network will also serve to greatly benefit ongoing research and action in rural New Zealand.

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  • A novel genetically encoded voltage indicator for studying motor cortical circuitry

    Scholtz, David Johannes (2014)

    Undergraduate thesis
    University of Otago

    The primary motor cortex (M1) consists of layers that are occupied by distinctive excitatory pyramidal neuron and inhibitory interneuron populations. Neurons within each layer receive inputs from numerous cortical and subcortical structures that relay proprioceptive and sensory feedback to modulate motor outputs and facilitate motor learning. The neurons within the upper layers (layer 2/3) are linked with processing and integrating these inputs and activating the circuitry that generates motor output commands that drive voluntary movement. To date our understanding of how these circuits achieve this remains elusive. Our poor understanding arises from technical challenges associated with studying the simultaneous behaviour of the electrical activity of the vast diversity and complex connections of the neurons within these circuits. To overcome this limitation we aim to use a Genetically Encoded Voltage Indicator (GEVI) called VSFP-Butterfly 1.2 that is endogenously expressed in layer 2/3 pyramidal neurons M1 in a transgenic mouse. We aim to determine the fidelity of VSFP-Butterfly 1.2 expression in the transgenic mouse and its ability to report subthreshold synaptic fluctuations in electrical membrane potential as changes in fluorescence. VSFP-Butterfly 1.2 is engineered to be expressed in layer 2/3 pyramidal neurons downstream of the Ca2+ Calmodulin-dependent protein kinase 2 (CAMKII). Immunohistochemistry for CAMKII in layer 2/3 of M1 slices found that the majority of neurons that express VSFP-Butterfly 1.2 also clearly express CAMKII (99.24 ± 0.567 %, n = 9 slices from 6 mice). Simultaneous recording of local field potential (LFP) and VSFP-Butterfly 1.2 fluorescent optical signals from layer 2/3 of slices from the M1 in response to extracellular electrical stimulation revealed a clear voltage-response relationship for VSFP-Butterfly 1.2 (n = 8 slices from 4 mice). Pharmacological excitatory synaptic antagonists dampened both the optical VSFP-Butterfly 1.2 (P < 0.0001, One-way ANOVA multiple comparisons, n = 4 slices from 2 mice) signals and LFP responses (P < 0.0001, One-way ANOVA multiple comparisons, n = 4 slices from 2 mice); and all responses were eliminated by tetrodotoxin which is known to block all voltage dependent electrical activity in neurons (P < 0.05, One-way ANOVA multiple comparisons, n = 2 slices from 1 mouse). In addition, we provide evidence that VSFP-Butterfly 1.2 can report membrane potential fluctuations at distances as far as 793.6 μm from the recording column (P < 0.0001). Our results show that VSFP-Butterfly 1.2 is reliably expressed exclusively in layer 2/3 neurons of the M1 in the transgenic mouse where it accurately reports physiologically relevant electrical synaptic responses. Our validation supports the future use and exciting benefit of this mouse to begin to understand the basis of network and circuit connectivity during motor output and motor learning.

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