In newborn infants, birth asphyxia represents the predominant cause of brain injury. These infants will later exhibit neurodevelopmental disabilities or a more major cerebral palsy. Prevention of adverse outcomes requires an understanding of the way in which these deficits develop. Endogenous protective mechanisms arising from the insult have opened new insights in neuroprotective strategies. Neurotrophic factors such as IGF-1 and its N-terminal tripeptide GPE have been shown to confer some neuroprotection after HI injury in the adult rodent. In the P21 rat brain after moderate HI injury, exogenous intracerebral and intraperitoneal injections of GPE (30μg and 300μg respectively) were neuroprotective in the hippocampus and lateral cortex possibly through binding to glia as detected by autoradiography of 3H-GPE. In the preterm infant the mechanisms of white matter injury remain to be clearly elucidated. To mimic the pattern of diffuse cerebral injury of the very preterm infant, a transient moderate focal HI injury has been applied on the immature P3 rat. This new model showed a significant reduction in the lateral cortical volume with reduction and alteration of the myelination pattern in the cortical white matter (WM) at P21. These cortical alterations result from neuro-axonal damage 24h after the insult as shown with Fluoro-Jade B staining and β-APP accumulation. In addition activated astrocytes from 24h after HI up to P21 were present. This model should enable us to elucidate some of the pathogenic mechanisms involved in diffuse WM injury. Brain damage in the developing brain has two components: 1) the pattern and mechanisms of injury are correlated with the stage of development at the time of injury; 2) it will influence subsequent brain development.

Ischaemic cell death has been implicated in a number of retinal diseases, including glaucomatous neuropathy, proliferative diabetic retinopathy and a range of vascular diseases. The cascade of events leading to cell death involves both cellular metabolic changes and a functional component. However, it is yet unknown how long these changes persist, whether all cell classes are affected, and the characteristics of recovery. Moreover, there have been few studies correlating the neurochemical changes with the ensuing functional changes. The aim of this thesis was to track the metabolic and functional recovery of the ischaemic rat retina, given the premise that: (1) amino acid neurochemistry reflects metabolic integrity and cellular identity, and; (2) the permeation of a cation channel probe called agmatine reflects channel functionality. Quantitative pattern recognition analysis of overlapping amino acid and agmatine expression profiles were used to provide a statistically robust classification of cells according to metabolic and functional characteristics. This classification was spatially complete and with single cell resolution. Finally, the electroretinogram was used to also assess retinal function and corroborate the observed neurochemical changes. These measures were taken at intervals for up to two weeks of reperfusion. The results show that by 48 hours of reperfusion, amino acid metabolism had returned to near normal levels, although cell classes were missing, and there was persistant cation channel gating anomalies. Immunocytochemical labeling identified a preferential loss of cone bipolar cells, with all remaining rod bipolar cells showing increased cation channel gating. The electroretinogram and agmatine experiments showed that this dysfunction is likely due to abnormal glutamate release from pre-synaptic photoreceptors, detected by changes in post-synaptic agmatine permeation, and not due to the presence of anomalous metabotropic glutamate receptors. Cholinergic amacrine cells demonstrated persistant neurochemical labeling, but did not show cationic flux following stimulation by glutamate agonists. In conclusion, the retina shows remarkable recovery in the amino acid metabolism, although functional changes persist. Finally, structural integrity or immunocytochemical labeling does not necessarily imply that cells maintain functional receptors, or that neurotransmitter release is normal secondary to disease. / Whole document restricted, but available by request, use the feedback form to request access.

Ovine placental lactogen (oPL) is secreted by the placenta into both the fetal and maternal compartments. Its biological function(s) during pregnancy and the mechanisms involved are still unclear. A purification procedure was developed for oPL from sheep placental cotyledons of late gestation. Four procedures were attempted to obtain homogeneous oPL. Recoveries of oPL and total protein were measured throughout the several procedures using a specific oPL RIA and the Bradford protein estimation respectively. The third and fourth procedures resulted in homogeneous oPL and a partial amino acid sequence was obtained from the fourth procedure. In the successful procedures, the placental tissue was extracted with 0.1 M ammonium bicarbonate pH 8.5. A pH precipitation of the soluble fraction was performed, followed by 60% saturation with ammonium sulphate. Further separation steps involved chromatogaphic procedures. Carboxymethylcellulose (CM32) cation exchange was performed batchwise at pH 5.6. Subsequently chromatofocusing was performed to elute proteins in order of their isoelectric points. This was carried out using a pH gadient of 0.9 to 6.0. The final chromatographic step was reverse-phase high performance liquid chromatography (RP-HPLC) using a C4 column. To obtain homogeneous oPL in the third procedure, the partially purified oPL was subjected to SDS polyacrylamide gel electrophoresis and the separated proteins were transferred to nitrocellulose membrane. The homogeneous oPL was eluted from the membrane, however, sequencing was unsuccessful. It was assumed that the N terminal of oPL was blocked. Homogeneous oPL was obtained in the fourth procedure by electrophoretic elution from the Hunkapiller gel system performed at 4°C. The oPL was digested with trypsin, the fragments were separated by RP-HPLC chromatography and two peptides were sequenced. Peptide 1: F D E Q Y G Q G I Peptide 2: Y I N C H T Several strategies were attempted to provide more homogeneous oPL to enable more sequencing. The partially purified oPL fractions from each of these attempts were pooled and electrophoresed on an SDS polyacrylamide gel. The section of acrylamide containing the oPL band was homogenised and a trypsin digest was performed. The digested oPL was separated from the gel pieces, filtered through a Sep-Pak filter and the fragments were separated by RP-HPLC. The yield of oPL was low, but sufficient homogeneous oPL was obtained to provide a partial amino acid sequence from tryptic peptides. A further two peptides provided sequences. Peptide 3: (L) A G E M V N R F D E Q Y G Q G I Peptide 4: (L) Q P G K C Q I P L Q S L F Collaborators from Genentech Inc (San Francisco USA) used partially purified oPL produced from the present study and also obtained homogeneous oPL (Colosi et al., 1989). Complementary DNA clones of oPL were isolated and expressed in mammalian cells by recombinant DNA techniques (Colosi et al., 1989). These clones were sequenced, demonstrating that the full sequence of oPL consists of 198 amino acids preceded by a 38 amino acid sequence signal. Recombinant oPL was generated by Colosi et al. (1989) which provided sufficient material to perform physiological studies in vivo. The somatogenic effects of recombinant oPL were investigated in the growth hormone (GH) deficient dwarf rat and compared to identical doses of recombinant bovine GH (bGH) in 3 independent studies. Both oPL and bGH treatments resulted in an increase (p<0.05) in body weight gain compared to that in saline treated controls, with oPL treatment being more potent than bGH (p<0.05). In promoting linear growth, oPL was more potent (p<0.05) than bGH in some instances. Nitrogen content of dry carcass matter was increased with oPL treatment compared to saline (p<0.05), with a nonsignificant increase in bGH treated animals. Carcass fat was similarly reduced by both oPL and bGH treatment (p<0.05) compared to saline. Serum insulin-like growth factor I (IGF-I) concentrations were increased significantly (p<0.05) by both oPL and bGH treatments, with a significantly greater effect of oPL suggested in one study. No increase in hepatic IGF-I mRNA was evident with either treatment, suggesting that the increase in serum IGF-I is due to posttranscriptional mechanisms. The expression of IGF binding protein 3 (IGFBP-3) hepatic mRNA was increased (p<0.05) with bGH treatment compared to that after saline treatment, but was unaffected by opL treatment, indicating regulation by GH at the transcriptional level. The binding of [125I]bGH to hepatic membrane preparations demonstrated no difference in specific binding compared to that in saline controls. However, [125I]oPL specific binding was greater in oPL treated animals (p<0.05). Animals treated with bGH had reduced (p<0.05) hepatic GH receptor mRNA compared to saline controls, but oPL treatment had no effect. Thus, oPL is a potent anabolic and lipolytic agent in the dwarf rat, exerting greater somatogenic effects on some parameters than bGH. The studies in this thesis have described biochemical and biological characterisitics of oPL. The amino acid sequence of oPL is more closely related to prolactin (PRL) than to GH (Colosi et al., 1989). However, oPL has potent somatogenic activities in the GH deficient dwarf rat. Our data suggest differences in receptor binding and effects on GH receptor and IGFBP-3 expression with these two treatments, raising the possibility of actions through different pathways or differential effects at the GH receptor level. These results do not fully resolve whether GH and PRL exert all effects through a single receptor or whether there is a separate PL receptor.

This thesis uses the concepts and methods of community psychology, and. applies them to what is called here a “comprehensive community project”. This is a project that undertakes to meet the needs of a community by fostering and strengthening the community’s own resources. The objectives of the research were : (1) to establish a comprehensive community project in the Auckland. suburbs of Birkdale and Beachhaven, and (2) to propose and. test a model for project organization and evaluation. The model was derived. from the systems approach to programme evaluation which provides a reasoned and. logical approach to all aspects of programme management. The model proposed involved systematic steps from initial programme planning to outcome measurement. The steps are, specifying the "system” or particular project, forming the values from which interventions would be derived, assessing needs and. resources, setting annual goals for activities from the foregoing steps, allocating available resources to activities, implementing and. reviewing activities, measuring outcome after one year, and feedback of this information for project improvement. Application of the model to the “Birkdale Project” showed that the model was relevant to management needs, and. Information yielded by application of the model was used. in day-to-day decision making. Thus the model was instrumental in establishing the Birkdale Project, and. in producing the vigorous project that resulted. in the first year a wide range of activities involving a significant portion of the population were provided. to meet community needs, and almost all the Project’s annual goals were attained. Although the project was established largely by paid professionally trained people, at the end. of the research period. the project was managed and run by non-professional residents. It was concluded. that the systems approach is highly appropriate to the development of comprehensive community projects, and has general advantages to the wider field of community psychology as a method for practice and research.

Investigations were undertaken to describe and quantitate the topographical abnormalities which develop in the organ of Corti as a result of acoustic trauma, and to determine their relationship to the associated losses of cochlear function assessed by the compound action Potential (N1) and cochlear microphonics (CM). Thirty guinea pigs were exposed, while anaesthetised, to a tone of 3 KHz at 125 dB SPL for 30 minutes. Both organs of Corti were examined by scanning electron microscopy either immediately or 1,3,7 or 14 days after exposure. In the second study 26 anaesthetised guinea pigs were exposed to 5 KHz at 125 dB SPL for 30 minutes. Cochlear potentials were recorded from the round window of the right cochlea and N1 audiograms (sound Pressure level required to elicit N1 Plotted against frequency) and 10 μv isopotential curves (sound pressure level required to produce 10 μv CM plotted against frequency) were produced for each animal either within one hour or 1,7,14 or 28 days later. The same organ of Corti was examined by scanning electron microscopy. Cochlear potentials were compared to mean values from 16 normal guinea pigs. Most animals developed topographical changes in one or both organs of Corti after exposure to 3 KHz (90%) and in the right organ of Corti after 5 KHz (92%). There was a wide variation in both the length (3 KHz: 0.1-4.15 mm; 5 KHz: 0.5-16.0 mm) of lesions and the number of hair cells affected. Both these indices of damage increased significantly (p <0.01) in the 24 hours following exposure to 5 KHz. Early damage to hair cells included either collapse, fusion or loss of stereocilia and there was an increase in the proportion of affected cells towards the centre of the lesions where supporting cells were damaged also. Subsequent to exposure, collapsed stereocilia appeared to become fused and some hair cells, particularly OHC, with stereocilia abnormalities were lost. However, others, particularly IHC, remained for up to 28 days despite abnormal stereocilia. Early changes occurred around the position of maximum displacement of the basilar membrane and subsequent extension of the lesions occurred equally in both apical and basal directions. Fusion was the only stereocilia change to develop after exposure. Regions of the organ of Corti showing supporting cell damage were replaced within 3-7 days by the proliferation of inner sulcus and Claudius’ cells. The substantial initial loss of both N1 thresholds and CM sensitivity partially recovered during the first 24 hours after exposure, but paradoxically, this was associated with the significant increase in the topographical changes in the organ of Corti. N1 threshold loss occurred over all frequencies and was maximum 1/2 – 1 octave higher than the exposure frequency (5 KHz). All lesions occurred within regions corresponding to changes in N1 thresholds. In the first 24 hours topographical changes occurred over a much smaller area of the organ of Corti than indicated by changes in N1 thresholds. Seven or more days later the longer lesions (30%) reflected the extent of changes in N1 but the remainder were smaller than indicated by this functional loss. This suggests that functionally important damage to the cochlea is more extensive than indicated by hair cell loss, stereocilia abnormality or supporting cell changes in the organ of Corti. Therefore, investigations of the effects of noise should not be based simply on topographical changes in the organ of Corti as these often underestimate the extent of injury to the cochlea.

The introduction to this thesis is a literature review. Kramer, in a study commissioned by WHO, reviewed the literature prior to 1985 on low birthweight. This is extended, mainly in respect to infants who are small for gestational age with emphasis on important findings in relation to birthweight since that time. Work in New Zealand on birthweight is also summarised. The literature is also reviewed in respect to the mechanisms in the pathway between the placenta and the fetus, and in respect to recent work suggesting a link between birthweight and disease in adult life. This thesis examines factors that influence birthweight and placental weight. Birthweight for gestational age percentile curves for the New Zealand population were firstly defined. small for gestational age (SGA) infants could then be categorised. The thesis considers two sources of data, the first a cross-sectional sample of the New Zealand population from 1987 to 1990 (the control subjects of the New Zealand cot Death study, a national case-control study on sudden infant death syndrome), and the second a hospital population in Auckland (National Womens Hospital (l992)). These two datasets are investigated to determine factors that influence birthweight in a univariate situation and then in the multivariate situation. Independent variables are considered using a priori categorisations and where appropriate Quantile-Quantile (Q-Q) derived categorisations determined by producing plots of the quantiles of cases versus controls. A number of variables under the headings of socio-demographic, lifestyle, genetic, obstetric and nutrition are examined and found to be associated with the outcomes of interest at the univariate level. After controlling in multivariate analyses a number of variables are found to be no longer significant, however some show strong relationships. The variable relating to smoking in both datasets shows the greatest detrimental effect on the outcomes considered in respect to birthweight. This confirms that in New Zealand, as in other places in the world, smoking has significant consequences on birthweight. The data is also investigated for the timing of insult to the fetus from smoking, and is found to be most important during pregnancy. comparison of the results comparing those obtained using a binary outcome for SGA, and those obtained using birthweight continuously, show relatively consistent results. The odds ratios and the decreases in birthweight obtained from both datasets show a relatively linear relationship between the two. An examination into whether a distinct group of individuals exists in respect to having large placentae for birthweight, indentified an artefact in the dataset relating to recording of placental weight for twins. After removal of twins from the dataset, examination of factors that influence placental weight showed that the factors that influence placental weight are not the same as those that influence birthweight. In particular smoking is found not to influence placental weight, and haemoglobin, which has no influence on birthweight, is found to be inversely associated with placental weight. other factors such as parity are found to influence placental weight in the same proportion in which birthweight is affected. In conclusion this thesis shows that factors investigated in New Zealand are consistent with findings in the international literature in relation to birthweight. The results on factors that influence placental weight add to the international literature on a topic on which little work has been carried out. The results of this thesis point to areas where future research needs to be carried out, in particular in relation to maternal nutrition during pregnancy and maternal energy expenditure during pregnancy. There is also a need for further research into the relationships of factors on placental weight and the ratio of birthweight to placental weight, and how these relationships affect health outcomes in childhood and adult life.

Over the past decade, a number of epidemiological studies have provided significant evidence that certain major adult noncommunicable diseases, such as hypertension, ischaemic heart disease and non-insulin dependent diabetes mellitus, may be associated with impaired fetal growth. This phenomenon has been termed "programming" which is essentially the term used for persisting changes in structure and function caused by undernutrition or other adverse influences acting during critical periods of early development. Programming has been used as the mechanistic basis to explain the long term sequelae of intrauterine growth retardation (IUGR). The mechanisms underlying the epidemiological observations remain to be elucidated and developed. While it is well established that severe maternal undernutrition during pregnancy leads to IUGR, there has been relatively little well defined animal studies of the somatotrophic axis and postnatal development of growth retarded offspring. The major objectives of this thesis were to establish a model in the rat of IUGR by nutritional restriction of the dam throughout gestation and to examine the effects of fetal growth retardation on endocrine, molecular and growth parameters during postnatal development. In addition, the development of an animal model for IUGR enabled well defined studies testing distinct hypotheses suggested by the epidemiological observations of professor David Barker and colleagues. Timed matings were performed in Wistar rats and dams were randomly assigned to one of two dietary treatment groups. A control group was fed ad libitum throughout pregnancy and a restricted group was fed 30% of ad libitum intake. Restricted fed dams were observed to lose a significant amount of body weight throughout gestation, due to undernutrition, but caught up to the ad libitum group during the lactating period. Maternal undernutrition significantly reduced fetal and placental weights without altering litter size. Postnatally, body weights of offspring from undernourished dams continued to be reduced until at least 18 weeks of age, although they were observed to be growing at the same rate as ad libitum offspring by 2 weeks of age. A cohort of animals from undernourished dams were maintained to measure blood pressure by tail cuff plethysmography. Offspring from undernourished dams were found to have significantly elevated systolic blood pressures from 18 weeks of age. This observation provides direct experimental support for the hypothesis, derived from human epidemiological studies, that the origin of adult hypertension may originate during fetal life as a result of exposure to a sub-optimal intrauterine environment. Parallel reductions in plasma IGF-I and hepatic IGF-I mRNA concentrations before 15 days of age were also observed in growth retarded offspring. Hepatic IGF-I transcription start sites within exon 1 and exon 2 were coordinately reduced with IUGR up to 15 days of age without changes in GHR and GHBP mRNA abundance. The lack of catch-up growth observed in the IUGR offspring despite normalization of their plasma IGF-I and IGF-I mRNA levels from 15 days of age may be due to a state of partial resistance to GH. This observation lead to a series of treatment studies in which neonatal and juvenile offspring from ad libitum and undernourished dams were treated with growth factors to investigate somatic growth responses as a measure for hormone sensitivity. In both treatment studies, ad libitum offspring from both age groups and juvenile IUGR offspring responded to GH treatment However, neonatal IUGR offspring did not exhibit any response to GH treatment.. Analysis of IGF-I gene expression in neonatal offspring showed that GH treatment elevated IGF-I Eb mRNA in ad libitum but not IUGR offspring. These results suggest a possible mechanism for transient GH resistance in that a post-receptor defect in GH action may contribute to the development of temporary postnatal GH resistance as a consequence of IUGR and fetal programming of IGF-I gene expression. In summary, the development of a model of IUGR in the rat using maternal undernutrition throughout gestation has enabled detailed investigation of nutritional regulation of the somatotrophic axis during fetal development and postnatal sequelae. The studies in this thesis have shown that the somatotrophic axis is markedly altered postnatally by nutritional restriction of the dam throughout gestation, leading to prolonged postnatal growth retardation and elevated blood pressure The mechanisms which lead to the induction of such fetal programming and whether these changes may contribute to the development of subsequent adult-onset disease remain to be addressed in future studies.

This thesis is based on two theoretical models of chronic illness: Large, Butler, James, and Peters (1990) introduced a systems model of musculo-skeletal pain which incorporated many of the variables believed to be important in the development and maintenance of pain. Feldman’s model (1974) addressed the difficulties of adapting to chronic illness. Five studies evaluated specific aspects of these models. The epidemiology of pain in New Zealand (NZ) was derived from a psychiatric epidemiology project. Approximately 80% of NZ adults had experienced a life disrupting episode of pain which had required medical consultation. Subjects who reported episodes of pain were more likely to have psychiatric diagnoses of anxiety, depression, and phobia. They were more likely to describe their health as poor and were currently consulting their doctor more than people who did not report an experience of pain. The estimated average cost of health consulting by people attending Auckland Hospital Pain Clinic (AHPC) for the previous year was $1333(NZ). Most people had some subsidy of costs. The health consulting of the AHPC group was higher than that reported in the NZ health literature. Self image and the experience of pain were assessed in two studies. The first asked subjects at AHPC to describe the typical thoughts, feelings, and behaviours, of someone with chronic pain. Subjects described loss of self esteem, alienation from family and friends, fear of the future, frustration and anger. The descriptions focused on psychological aspects of the experience of pain. The second study of self image used repertory grid technique. Two standardised Illness Self Construct Repertory Grids (ISCRG) were evaluated. Issues in the use of standardised grids are discussed and some aspects of ISCRG application are explored. The two ISCRG indicated subjects often identified themselves as a physically ill person and felt isolated from others. People with pain and their "closest other” (CO) completed the ISCRG(A) and questionnaires on the quality of their relationship. Closest others overestimated the role of the physical illness in their partners’ life and believed that they understood them better than the individual with pain thought they did. The personality dimensions of alexithymia and hypnotisability have been hypothesised as pathways for the development of psychosomatic illness. Individuals with chronic pain were tested to establish whether they weremore alexithymic and more hypnotisable than subjects in a general population control group. This was not verified. The constructs of alexithymia and hypnotisability require critical examination. The experience of pain is common and is associated with psychological distress and high health service use. Self construct appears to be a major factor determining response to pain and to treatment programmes. Chronic pain appears to be a particular challenge for individuals who must accept alteration in their lifestyle with perhaps little understanding of what the future may hold. / Whole document restricted, but available by request, use the feedback form to request access.

Testicular function is stimulated from the pituitary gland by the gonadotrophic hormones FSH and LH. The testis in turn regulates gonadotrophin secretion by negative feedback. The agents of feedback are steroids, and in addition, probably a protein hormone, which has been given the name inhibin. A method capable of detecting inhibin-like activity in bull seminal plasma (bSP) was developed. Administration of bSP at the time of castration to five-week old male rats inhibited the post-castration rise of serum concentrations of FSH and LH otherwise seen 24 h later. The degree of inhibition depended on the dose; 0.5 ml bSP or the equivalent amount of bSP-extract always suppressed FSH and LH to levels typical of intact rats. The rats' sensitivity to 0.2 ml bSP varied with the time of year, possibly reflecting seasonal changes in the onset of puberty. The time-course of action of bSP-extract was studied in intact rats. Serum FSH was suppressed 12, 24 and 48 h after a single injection, but not at 3 or 6 h. LH was suppressed at 6, 12, 24 and possibly 48 h.

Human mammary tissue was incubated in vitro with [7-3H] dehydroepiandrosterone sulphate (DHA-sulphate) and in agreement with other investigators this steroid conjugate was metabolized to DHA and other steroid products. Sulphatase activity was greater in the malignant than the non-malignant tissues and was found to be a function of the tissue cellularity. One of the major products, a "polar steroid" necessitated identification. The "polar steroid" was identified principally as 7a-hydroxy DHA by chemical modification techniques and co-crystallization of the purified steroid metabolite with carrier 7a-hydroxy DHA. This carrier required synthesis and characterization.