14,464 results for Doctoral

  • GABAA receptors in the basal ganglia of the rat, baboon and the human brain

    Waldvogel, Henry J. (2000)

    Doctoral thesis
    The University of Auckland Library

    Restricted Item. Print thesis available in the University of Auckland Library or may be available through Interlibrary Loan. The regional, cellular and subcellular distribution of GABAA receptors was investigated in the striatum and globus pallidus of the rat, baboon and human brain using receptor autoradiography, and multiple immunohistochemical labelling techniques at the light, confocal and electron microscopic levels using antibodies to the α1, α2, α3, β2,3 and γ2-subunits of the GABAA receptor complex. The results demonstrated that GABAA receptors in the striatum showed considerable subunit heterogeneity in their regional (primate brain) and cellular distribution (rodent and primate brain). At the regional level in the baboon and human brain, GABAA receptors in the striosome compartment contained the α2, α3, β2,3 and γ2-subunits while receptors in the matrix compartment contained the α1, α2, α3, β2,3 and γ2-subunits In general terms in both the rodent and the primate brain, up to six different types of neurons were identified in the striatum. There was considerable species diversity in the cell types. Two main types of neurons (type 1 and type 2) immunoreactive for the subunits α1,β2,3,γ2 were identified in the striatum. They were GAD positive and were classified according to their cellular morphology and staining properties; rat type 1 neurons were GAD positive only, while human type 1 neurons were GAD and parvalbumin positive. Type 2 neurons were identified in both the rat (GAD positive only) and in human (GAD and calretinin positive). All three mammalian species showed the presence of type 3 neurons which were large neurons with few spines and immunoreactive for subunits α1,3,β2,3,γ2. Type 4 neurons were calbindin positive and immunoreactive for subunits α2,3,β2,3,γ2. The remaining neurons were immunoreactive for ChAT and the α3-subunit (type 5), or immunoreactive for neuropeptide Y with no GABAA receptor subunit immunoreactivity (type 6). The globus pallidus contained three types of neurons; type 1 neurons contained parvalbumin and type 2 contained parvalbumin and calretinin and both were immunoreactive for subunits α1,β2,3, γ2 while type 3 neurons were medium-sized calretinin neurons immunoreactive for the subunits α1,β2,3,γ2 At the ultrastructural level in the globus pallidus, α1 and β2,3-subunits were localised on large neurons (types 1 and 2) and were found at three types of synaptic terminals. These results show that the subunit composition of GABAA receptors displays considerable regional and cellular variation in the striatum, but is more homogeneous in the globus pallidus.

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  • The Long-term effects on antenatal glucocorticoids and preterm birth

    Dalziel, Stuart Ryan (2005)

    Doctoral thesis
    The University of Auckland Library

    Restricted Item. Print thesis available in the University of Auckland Library or may be available through Interlibrary Loan. Antenatal glucocorticoids are widely used in perinatal medicine, and are one of the key treatments responsible for improving survival of preterm infants since the 1960s. A systematic review reported in this thesis concludes that antenatal glucocorticoids reduce the risk of neonatal death, respiratory distress syndrome (RDS), intraventricular haemorrhage, necrotising enterocolitis, infectious morbidity and need for respiratory support. Several areas of uncertainty have been clarified, including the effectiveness of treatment in the current era of neonatal practice, and in women with hypertension syndromes and premature rupture of membranes. However there is a paucity of data on long-term outcomes after exposure to antenatal glucocorticoids. This is particularly important given recent proposals that fetal exposure to excess glucocorticoids may be a core mechanism explaining the epidemiological evidence that those born small are at increased risk of later adult disease. Furthermore, the relative contributions of fetal growth and prematurity to small size at birth, and hence later disease risk, has not been well elucidated. This thesis reports the follow-up of 534 thirty year olds whose mothers participated in the first, and largest, randomised trial of antenatal betamethasone for prevention of neonatal RDS. Two-thirds of participants were born preterm. Follow-up assessments included cardiovascular risk factors, spirometry, psychological assessment and bone densitometry. Exposure to antenatal betamethasone did not affect mortality, body size, blood pressure, lung function, fasting plasma levels of lipids, cortisol or IgE, socio-economic status, psychological functioning, health related quality of life or bone mass. However betamethasone-exposed participants showed increased insulin resistance. This is the first experimental evidence in man to demonstrate long-term metabolic effects of fetal glucocorticoid exposure. However, as all other outcomes are reassuring, and treatment significantly reduces neonatal mortality and morbidity, obstetricians should continue to use a single course of glucocorticoids for the prevention of neonatal RDS. Adults who were born preterm had increased blood pressure, insulin resistance, reduced lung function and reduced adult height at age thirty. This is the largest reported follow-up of ex-preterm infants into adulthood. Although the associations are relatively small, their potential implications for the prevalence of later chronic obstructive pulmonary and cardiovascular disease are of concern.

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  • Rarotongan society: the creation of tradition

    Baddeley, Josephine Gail (1978)

    Doctoral thesis
    The University of Auckland Library

    Restricted Item. Print thesis available in the University of Auckland Library or may be available through Interlibrary Loan. This work examines aspects of contemporary Rarotongan society selected to illustrate how Rarotongans structure their reality. This is not a study of social change, but it does show how the vestiges of ideologies from the past have been reinterpreted and incorporated into the contemporary society. To demonstrate how the “traditional” ideologies have survived and co-exist with “modern” ideas, institutions of a pre-European origin, such as adoption practices, Māori medicine and the transmission of chiefly titles, are discussed. Rarotongans may view these and other customary practices according to several criteria from which they choose the one which is most appropriate to their purposes on any particular occasion. It is shown that Rarotongans are in the process of creating a cultural tradition which incorporates elements from their traditional past and European influences which are being transformed into something that is perceived as essentially Rarotongan.

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  • Advocacy for Using Evidence in Public Health Nutrition Policy Making

    Field, Penelope Anne (2014)

    Doctoral thesis
    University of Otago

    Do advocates for using evidence make a difference? A case study of public health nutrition policymaking in New Zealand. There is a growing body of evidence supporting interventions that will effectively address nutrition-related non-communicable disease. However, researchers and other stakeholders often despair that such evidence is not informing government policy. The emerging field of ‘evidence-informed’ policy addresses the question, ‘What works?’ to improve the use of evidence in policymaking. This thesis aims to contribute to this enquiry by exploring how advocates for the use of evidence can make a difference. Advocacy can connect science, society and politics and build ‘multiple footbridges’ between the worlds of decision makers and those who generate evidence. A theoretical model for advocacy for evidence use was developed following an extensive literature review. The model was evaluated against a rival explanation in a policy case study of food marketing to children. Data were collected by interviews with senior members of the New Zealand public health nutrition policy community, documentary analysis and field notes. Results indicate that current policymaking systems are ad hoc and non-deliberate, informal relationships are the primary channel by which evidence informs bureaucrats’ decision making and the powerful role of meta-level policy is largely unknown. Major determinants of advocacy activity are access to resources and the opportunities presented by political timing. Concurrently the trend for sovereign government to be replaced by governance mechanisms and a government agenda to give science a greater role in policymaking are shifting established policy processes. These factors, together with a growing realisation that public health nutrition policymaking needs a paradigm shift, are creating opportunities for advocacy for the use of evidence. The findings of this research lead to the conclusion that public health nutrition policy processes will deliver better outcomes when the ‘idea’ of using evidence is actively advocated. Politically aware advocacy should enhance evidence use when it brings about shifts in meta-level policy, policymaking processes and relationships across the policy community.

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