<p>After specific causes of chronic insomnia have been ruled out (e.g., noctural myoclonus, drug abuse), there remain in a substantial number of patients who have been inexplicably sleepless and fatigued for many years. We wished to learn whether the chronicity of insomnia in these patients was associated with phase-shifts in circadian rhythm, a disorder of internal timekeeping. We identified three types in a pilot study: 1) phase-delay, b) phase-advance, and c) an arrhythmic group.</p> <p>Delayed sleep-phase insomnia (DSPI) has been well described. It is characterized by an intractably late sleep-onset and awakening time, a consistent sleep time-frame, and an essentially normal sleep EEG.</p> <p>Advance sleep-phase insomnia (ASPI) is a much rarer phenomenon, with few reported cases. Sleepiness becomes overpowering in the late afternoon or early evening, followed by a very short sleep onset latency and exceedingly early awakening time. The EEG is essentially normal.</p> <p>Amplitude disorders and arrythmia are even more rare under normal environmental conditions. They have been described but not carefully examined. We identified two patients in the pilot study who displayed a complete arrythmia of their core temperature cycle. Their sleep was marked by variable onset latencies, and severe difficulties with sleep maintenance. Sleep-time averaged less than two hours per night, and was associated with a substantial reduction in the slow-wave sleep.</p> <p>Though these patterns sound easy to recognize, they are often obscured in patient reports. For example, social schedules requiring early rising for work in spite of phase-delay or explanations that patients develop to better account for their predicament may disguise true patterns. We tried to detect the more intractable features in patient histories and reported patterns of sleep and to predict which type of phase disturbance each might have.</p> <p>The physiological aspects of the circadian phase disturbance was examined using the sleep-wake cycle (14 x 24 hours), core body temperature (5 x 24 hours), serum cortisol (1 x 24 hours) and serum melatonin (1 x 24 hours) as circadian parameters. Monitoring was carried-out on three patient groups identified in the Sleep Disorders Clinic as being : 1) phase-delayed, 2) phase advanced, or 3) arrythmic.</p> <p>The phase-delay group showed a significant delay in the acrophase of core temperature rhythm, but not serum cortisol. The phase advance group showed a significant advance in the acrophase of both rhythm parameters. The arrhythmic group displayed a highly variable core temperature acrophase but intact 24 hour waveforms. Serum cortisol had no discernable rhythmic component in this group.</p> <p>The circadian rhythm of serum melatonin showed a significant acrophase delay for all patient groups. This was an unexpected result, as the phase control of melatonin secretion is thought to originate from oscillators providing phase information to the other parameters meausred in this study.</p> <p>Also important was the finding that there was no significant difference in the amplitude or period length for all three circadian rhythm parameters. Thus, "phase-disorders" seen in the present study possibly represent a defect in carcadian rhythm timing but not in the generation of rhythms themselves. However, in patient Group 3 the substantial increased point to point random variation in core temperature and the arrhythmic nature of the serum cortisol secretion could imply involvement of rhythm timing and/or generation.</p> <p>Since these phase disorders were associated with a consistent and unidirectional phase change in the circadian pattern of melatonin secretion, it is hypothesized that the pathology in these patients may lie at the level of the suprachiasmatic nucleus. Hyposensitivity to light could interfere with melatonin "offset" signals, while allowing other pacemakers to move toward their endogenous cycling frequencies. Thus, phase delayed, or advanced, or a more drastic rhythm anomaly might ensue.</p> <p>This study also indicates that it may be possible to identify each of the three types of rhythm disturbance on the basis of clinical features that can be obtained by interview. The most important aspects appear to be: 1) chronicity of symptoms, 2) consistency of symptoms, 3) pattern of symptoms, 4) psychiatric and medical histories, and 5) recnet drug histories. In addition, polysomnographic studies are required to exclude specific disorders such as nocturnal myoclonus.</p> <p>Exogenous melatonin administration was carried out on this patient sample. A double-blind, placebo-controlled, 14-day trial showed a significant improvement of both total sleep time and day-time alertness with a 75mg oral does of melatonin as compared to placebo. This is the first study to demonstrate significant clinical soporiphic effects of exogenous melatonin in chronic insomniac patients.</p> / Doctor of Philosophy (PhD)

<p>Evidence from the literature suggests that a limiting factor to the performance of exhaustive exercise is the ability of the brain to maintain the stimulation of the alpha-motor neuron. This these examined the hypothesis that this "central fatigue" results from a deficit in the transfer of information across striatal dopaminergic synapses. Decreases in striatal dopaminergic activity should impair exercise capacity whereas increases in dopaminergic activity should therefor improve exercise capacity. The rat was chosen as the experimental animal because of the availability of techniques to alter dopaminergic activity and to quantify exercise capacity. Striatal dopaminergic activity was reduced by depletion of striatal dopamine by an intracerebroventricular injection of 200mg of 6-hydroxydopamine. Dopaminergic activity was increases by an intreperitoneal injection of the specific dopamine receptor agonist apormorphine. Exercise capacity was quantified with treadmill-grid system by measuring the time taken for a running rat to become exhausted. Striatal dopamine depletion decreased exercise capacity whereas apomorphine increased xercise capacity. In contras, striatal and hpothalmic norepinephrine depletion had no effect on exercise capacity.</p> <p>The limitation of exercise capacity by the activity of striatal dopaoinergic synapses was not due to a failure of these synapses to maintain the release of dopamine, but may be due to these synapses releasing amounts of dopamine which are insufficient to transmit all the information arriving at the presynaptic terminal to the postsynaptic neuron. I propose that the release of dopamine is limited in exhausted rats by the activitation of presynaptic dopamine receptors located on the terminal and that the purpose of these receptors is to maintain the concentration of dopamine in the functional pool of the terminal.</p> / Doctor of Philosophy (PhD)

<p>This thesis examined developmental changes in morphology of the GnRH neuron in the female rabbit brain during sexual maturation. In the adult virgin rabbit approximately 1,000 GnRH cells were counted in half the hypothalamus. Two morphologically distinct populations of GnRH neurons were found. Fusiform cells with relatively smooth contours (smooth) accounted for 34% of the total. Cells with irregular contours (rough) represented 64% of the immunoreactive cells counted. In a subsequent experiment GnRH cell types were quantified in rabbits treated with Tamoxifen (TAM, 10 mg/kg/day), vehicle, and pregnant mare serum (PMS, 50 IU on postnatal days (PND) 25 and 28). Sexual maturity was considered achieved when rabbits attained a body weight of 3.0 kg. The proportion of rough cells increased while the smooth cells decreased with sexual maturation. This change was advanced by PHS treatment and prevented by TAM treatment compared to controls. Sexual maturity was advanced by PMS treatment (92 PND) versus controls (108 PND) and delayed by TAM treatment (128 PND). Mean plasma estradiol was significantly (P= 0.01) elevated in PHS rabbits versus controls between PND 25 and 34 and again at PND 75 (p= 0.05). Since the total number of immunoreactive cells remained constant, it is concluded that smooth cells are transformed to rough cells. In another experiment chronic ovariectomy did not change the total number of GnRH cells counted when compared to sham operated rabbits. However, the developmental shift of smooth cells to rough cells was prevented (p<0.05) in ovariectomized rabbits. These results suggest that the developmental change in GnRH cell morphology is functionally related to puberty onset. Moreover, estradiol seems to induce these changes through indirect mechanisms. It is proposed that estradiol augments the growth neural imputs to GnRH cells.</p> / Doctor of Philosophy (PhD)

<p>Asthma is a disease characterized by airway hyperresponsiveness (AH) to various spasmogens. Ozone-inhalation causes transient AH of human and canine airway smooth muscle (ASM) and has therefore been used as a model of AH. The mechanism(s) underlying ozone-induced or asthma-related AH are not completely understood, but there is a growing body of evidence that there is a causal relationship between airway inflammation and AH.</p> <p>In these studies, the mechanisms regulating canine bronchial smooth muscle (3rd to 5th order) activity were investigated using intracellular microelectrodes (to monitor electrical activity) and muscle baths (to monitor mechanical activity). The effects of ozone-inhalation and inflammatory mediators on regulation of ASM tone were also investigated.</p> <p>Excitation of ASM (membrane depolarization and contraction) was elicited by activation of muscarinic receptors or thromboxane receptors; the former were found to be of the M₃-subtype. The data indicated that pharmacomechanical (rather than electromechanical) coupling was involved.</p> <p>Inhibition of ASM was found to be initiated by activation of β-adrenoceptors; these were found to be predominantly of the β₁-subtype, though there was evidence that some β₂-adrenoceptors were also involved. There was evidence of physiological antagonism between cholinergic receptor-mediated excitation and adrenoceptor-mediated inhibition due to reciprocal effects on adenylate cyclase.</p> <p>Release of acetylcholine from the cholinergic nerve endings was antagonized by activation of muscarinic receptors (M₁-subtype) or adrenoceptors (both β₁- and β₂- subtypes), and potentiated by activation of thromboxane receptors; these receptor populations were presumed to be located on the nerve endings. There was indirect evidence that neurotransmitter-release was also antagonized by a cyclo-oxygenase metabolite of arachidonic acid (presumably PGE₂).</p> <p>Ozone-inhalation significantly enhanced contractions in response to electric stimulation, but did not significantly after those to exogenously-added cholinergic agonist or to KCl. This AH was prevented by indomethacin (cyclo-oxygenase inhibitor) or by L-670,596 (thromoboxane receptor antagonist). It was concluded that the mechanism underlying ozone-induced AH involved decreased prejunctional inhibition (mediated by PGE₂) and/or increased prejunctional excitation (mediated by TxA₂).</p> / Doctor of Philosophy (PhD)

<p>The proliferative behaviour of human lung fibroblasts in vitro was examined. Fibroblasts derived from the lung of patients with idiopathic pulmonary fibrosis proliferated faster compared to fibroblasts from control lung tissue. An examination of clonally-derived fibroblast lines showed a substantial degree of fibroblast heterogeneity which followed a normal distribution, and also the existence of a significantly greater number of fast-growing clones in the panels of clones derived from primary fibroblast lines established from fibrotic tissue. Heterogeneity with respect to the expression of collagen genes was also documented.</p> <p>The effect of an acute challenge of peripheral blood monocyte and/or alveolar macrophage supernatants on fibroblast proliferation was examined. Supernatants from peripheral blood monocytes and alveolar macrophages stimulated with lipopolysacharide elicited a dose-dependent inhibition of fibroblast proliferation, likely induced by interleukin 1. This effect could be prevented by pre-treating the fibroblasts with indomethacin and reconstituted by adding exogenous prostaglandin E$\sb2$, thus indicating the involvement of the prostaglandin E$\sb2$ pathway of the fibroblast. Exogenous prostaglandin E$\sb2$ directly caused an inhibition of fibroblast proliferation, and fibroblasts derived from fibrotic tissues were shown to be hyporesponsive to this mediator. Supernatants from unstimulated alveolar macrophages obtained from rats which had been given intratracheal bleomycin caused a similar effect on the proliferation of rat lung fibroblasts.</p> <p>Primary lines of fibroblasts chronically exposed to peripheral blood monocyte supernatants became hyporesponsive to both these supernatants and prostaglandin E$\sb2$, and released greater amounts of prostaglandin E$\sb2$, upon rechallenge compared to unexposed fibroblasts. An examination of clonally-derived lines showed marked heterogeneity in the responsiveness of individual clones to peripheral blood monocyte supernatants and prostaglandin E$\sb2$ as well as a change in the clonal distribution after chronic exposure to peripheral blood monocyte supernatants. Chronic exposure of sensitive clones to peripheral blood monocyte supernatants did not alter their level of responsiveness.</p> / Doctor of Philosophy (PhD)

<p>Endothelial cells contain a high density of vasoactive intestinal peptide (VIP) receptors. Since VIP is a potent vasodilator, activation of these receptors may lead to the release of endothelium-dependent relaxing factor (EDRF). Using patch-clamp techniques it was demonstrated that VIP modulates plasma membrane K$\sp+$ channels in bovine pulmonary artery endothelial cells. VIP inhibited activity of inwardly rectifying K$\sp+$ channels (I$\sb{\rm Kin}$) and activated opening of the Ca$\sp{2+}$-dependent K$\sp+$ channels (K$\sb{\rm Ca}$). Activation of K$\sb{\rm Ca}$ channels tends to hyperpolarize the cell membrane. This transient hyperpolarization increases the driving force for influx of extracellular Ca$\sp{2+}$ through nonselective cation channels. This way VIP may contribute to Ca$\sp{2+}$ influx necessary for the potential EDRF production.</p> <p>Although VIP activates adenylate cyclase and production of cyclic AMP (cAMP) in many cell types, this study provides evidence allowing us to exclude cAMP as a second messenger for VIP action in endothelial cells. Direct evidence comes from the measurements of cAMP level in bovine pulmonary artery endothelial cells stimulated with VIP and isoproterenol. Isoproterenol increased cAMP level, whereas VIP did not, or even decreased cAMP production in some cases. Indirect evidence comes from the results of patch-clamp experiments. VIP strongly suppressed I$\sb{\rm Kin}$ channel activity, whereas the inhibitory effect of isoproterenol on this channel was very weak (about 20% of the VIP effect). cAMP elevation may reduce the activity of I$\sb{\rm Kin}$ channel, but is not a mediator for the inhibitory effect of VIP on these channels. In addition, VIP was still able to inhibit I$\sb{\rm Kin}$ channel activity in outside-out patches, where the second messenger system is not operating. This effect was mediated by a G protein that most likely couples directly to the channel. This unidentified G protein revealed GTP-$\gamma$-S and cholera toxin sensitivity and resistance to pertussis toxin.</p> <p>Since elevated intracellular Ca$\sp{2+}$ is a trigger for EDRF production, it has been demonstrated that modulation of the calcium fluxes at the level of internal stores did influence an influx of extracellular Ca$\sp{2+}$. Cyclopiazonic acid (CPA), an inhibitor of SR/ER Ca$\sp{2+}$ pump, (i) induced K$\sb{\rm Ca}$ currents, presumably as a consequence of the spontaneous leakage of Ca$\sp{2+}$ from internal stores, (ii) reduced the I$\sb{\rm Kin}$ currents, and (iii) enhanced influx of extracellular Ca$\sp{2+}$ through nonselective cation channels. Moreover, CPA activated K$\sb{\rm Ca}$ currents in endothelial cells by a mechanism independent of 1,4,5-triphosphate (IP$\sb3$). An expected consequence of this action of CPA may be an influx of extracellular Ca$\sp{2+}$. In parallel studies, it has been demonstrated that CPA relaxed rat aorta in endothelium-dependent manner, suggesting CPA-induced release of EDRF. Ca$\sp{2+}$ enters the endothelial cell through nonselective cation channels, which can be activated by an agonist or a mechanical stimulus (e.g. stretch). It is still unclear whether these nonselective cation channels in bovine pulmonary artery endothelial cells are controlled by free intracellular Ca$\sp{2+}$, empty Ca$\sp{2+}$ ER stores or an agonist.</p> / Doctor of Philosophy (PhD)

<p>Significant differences in the cardiovascular mortality rate exist between Canadians of South Asian, Chinese and European origin. This thesis represents a six year effort to detennine the prevalence of cardiovascular disease, the burden of atherosclerosis, and the prevalence of their major determinants among three ethnic groups in Canada. In addition to the study of the relationship of the "classical" cardiovascular risk factors to disease outcomes, the contribution to disease outcomes of selected "emerging" risk factors (e.g. markers of thrombosis, socio-economic, dietary, and psychosocial stress factors) was studied.</p> <p>The major findings reported in this thesis include the confirmation that South Asians in Canada have the greatest prevalence, Europeans have an intermediate prevalence, and the Chinese have the lowest prevalence of cardiovascular disease. However, Europeans have significantly more atherosclerosis compared to the South Asians and Chinese. Yet, for any given amount of atherosclerosis, South Asians suffer more cardiovascular events. This may reflect an increased propensity of South Asians to develop arterial thrombosis.</p> <p>Major differences in the daily calorie consumption, and in the sources of calories exist between the ethnic groups. Diet was measured using food frequency questionnaires developed for each ethnic group, which were found to reliably classify individuals into high or low consumers for a given macronutrient. This classification facilitates the study of diet-disease relationships.</p> <p>Psychosocial stress was measured in a valid and reliable way using a single questionnaire created for use by all participants. Discrimination in the workplace is a challenge to measure, and while it was reported more often among South Asians and Chinese, its reproducibility was relatively low. Markers of social stability (e.g. income and employment) were associated with psychosocial stress factors, neurohormones, atherosclerosis and cardiovascular disease. This demonstrates the powerful influence that "social factors" have on the health of free-living Canadians.</p> / Doctor of Philosophy (PhD)

The aim of this research was to uncover the whole process of adapting to life with HIV. The research set out to consider the physical, psychological and social process of adapting to HIV and explore if stages of adaptation could be identified, presenting an up to date perspective of the HIV experience in light of new treatments and virus resistance. Glaser’s grounded theory method was chosen to gain a perspective on the whole process of adaptation and to develop a model reflecting this, useful to nurses and other professionals. The research was guided by the philosophical assumptions of Roy’s Adaptation Model. A second component of this research involved testing Roy’s Model of Adaptation by comparing it to the research results. The resultant grounded theory unveiled the process of adapting to life with HIV as a process of adapting to uncertainty. ‘Negotiating uncertainty’ emerged as the core concept. This was demonstrated by seven subcategories representing movements between anticipating hopelessness and regaining optimism. The results affirm many propositions of Roy’s Model whilst bringing new findings to the theoretical arena and highlighting areas for further clarification. The study concludes with recommendations for future theoretical and conceptual development to both the emergent grounded theory and Roy’s Adaptation Model.

Exposure to toxic elements is a significant threat to public and individual health worldwide. Toxic elements such as heavy metals are associated with increased mortality and morbidity in both men and women and are a substantial contributor to neurological deficits and developmental delay in children. Analysis of skeletal material yields important information regarding exposure to toxic elements in a given population. This project has investigated toxic element exposure in 215 adults living in urban South Africa who died between 1960 and 1999. Exposure to toxic elements, particularly exposure to lead, has significant impacts on human health, even at very low levels. To date, little research has been conducted on human exposure to toxic elements in adult urban South Africans and a clear gap exists regarding toxic element exposure rates during the latter half of the 20th century. Among the primary aims of this research is to address this gap in knowledge and to quantify human exposure to these elements during the apartheid era. Bone element concentration was analysed by ICP-MS to determine the concentration of six elements that are toxic to humans: lead, cadmium, manganese, arsenic, antimony and vanadium. The results of this research demonstrate clear racial divisions in toxic element exposure in all but one element investigated. In the case of lead and cadmium, white males in the sampled population show significantly higher bone element concentrations than either black males or black females. It is surmised that apartheid-era separation of racial groups in regards to residence, occupation and movement within the urban landscape are partly, if not significantly, responsible for these differences in toxic element exposure. Lead exposure is strongly associated with exposure to traffic in urban Pretoria and Johannesburg, which is evident in both the limited environmental data available and the present study. Designated residential areas for white individuals were situated in and adjacent to the central business districts of both cities and are the areas associated with high traffic. Black residential areas were located on the urban periphery, often near industrial areas and mine dumps. The result is a lead exposure pattern by which white individuals in the sampled population yield double the bone lead concentration of black individuals. The wide divide in socioeconomic strata between the black and white population also factors significantly and is an additional result of apartheid policy. For arsenic and antimony, black individuals, particularly females, show significantly higher bone element concentration than white individuals. These elements are strongly associated with acid mine drainage, a form of pollution which results from mining activity. The close proximity of black residential areas to mining activities and the heavy reliance on ii contaminated surface water is likely responsible for higher exposure rates to these elements in the black population. This research has established that rates of exposure to toxic elements in urban Transvaal were moderate considering the level of industrial and mining activity in the region and the notably lax environmental regulations in place during the latter half of the 20th century. Despite this, bone element levels, particularly that of lead, cadmium and manganese are within ranges documented to cause negative impacts on human health. It is highly likely, given the bone element concentrations reported here, that these elements caused significant and negative health effects in the sampled population and were a clear threat to overall public health in urban South Africans.

Anthropologists are increasingly called upon to assess trauma to the skeleton and contextualising the nature of this trauma. Blast injury is a type of trauma which is increasingly seen in a variety of contexts, such as terrorism, human rights violations, combat and accidents. The purpose of this study was to examine blast injury in the human skeleton and apply robust multivariate statistical methods, alongside morphological methods, to identify blast trauma based on the distribution of injury in the skeleton. The objectives of the study were to identify patterns in a sample of cases from mass graves in Bosnia and to determine differences between the blast injury cases and gunshot wound cases which can identify indicators of blast injury for future use. This was done using Pearson‘s χ2, cluster analysis and multiple correspondence analysis. Secondly, the identified indicators were applied to two methods of binary logistic regression model to test prediction of the presence or absence of blast injury in the sample, as well as assessing the results of the two methods. Lastly, the results of these analyses were subsequently compared with clinical literature to identify similarities and differences which can aid anthropologists in determining presence of blast injury in large assemblages. This also served to address the specific argument that the injuries seen in the Bosnia sample are combat related, as claimed in court proceedings in ongoing cases at the International Criminal Tribunal for the Former Yugoslavia. It was found that cluster analysis was not useful for the sample examined in the research, however multiple correspondence analysis permitted graphical differentiation between the blast injury and gunshot cases, identifying variables which contributed to the variance and could be used as indicators of blast injury. Binary logistic regression was employed to test the significant contribution of these variables to a model predicting the presence of blast injury in a sample. It was found that presence of trauma to the right shoulder girdle, left forearm, vertebrae, right pelvis and left femur could indicate the presence of blast injury in an assemblage, with correct average classification in 74.86% of cases. The prevalence of trauma in the Bosnia sample was compared with examples from terrorist incidents and combat situations to identify similarities and differences between these and found that there significant differences in the prevalence of trauma in the Bosnia sample. This highlights that this sample does not resemble any combat patterns of injury, answering the question posed in ICTY court proceedings. This work contributes new knowledge to anthropology on the identification and differentiation of blast injury in assemblages as well as demonstrating the use of multivariate statistical methods for trauma analysis. These results can be applied to anthropological investigation of historical contexts as well the modern investigations which will require knowledge of blast injury currently and in the future.