Research Methods in Life Sciences Commons^™

Effect Of Rearing Conditions On The Allocation Of Larval And Adult Acquired Essential And Nonessential Fatty Acids To Flight In Two Adult Lepidoptera: Danaus Plexippus And Mythimna Unipuncta, Libesha Anparasan

Electronic Thesis and Dissertation Repository

Insects which are nectivorous as adults acquire essential fatty acids, which are important for many biological processes, almost exclusively from the larval diet. Thus, adult allocation of this limited resource may result in trade-offs in migrant insects that delay reproduction. I used the true armyworm, Mythimna unipuncta, and monarch butterfly, Danaus plexippus, to test the hypothesis that environmental cues (fall migratory or summer reproductive) would influence the use of fatty acids during flight (0-6h). I used larval and adult diets manipulated isotopically (δ¹³C) and chromatographic analyses to determine fatty acid composition and source in the fat …

Vertebral Endplate Structural Defects: Measurement, Prevalence And Associated Factors, Aliyu Lawan

Electronic Thesis and Dissertation Repository

Objective: To synthesize current knowledge on the association of endplate structural defects (EPSD) with back pain (BP), improve EPSD measurement, and investigate EPSD prevalence, distribution, and association with age and body mass index (BMI).

Methods: In study 1, a systematic review was conducted on five databases for studies reporting on the association between EPSD and BP. Studies 2 and 3 used CTs and mCTs of 19 embalmed cadavers to examine the diagnostic accuracy of common EPSD assessment methods, and to develop and validate a novel method. Study 4 used the novel method on 200 adult males’ MRI to estimate EPSD …

Myeloarchitectonic Maps Of Cat Auditory Cortex, Austin Robertson

Electronic Thesis and Dissertation Repository

The cerebral cortex contains myriad cortical areas that differ in structure, function, and connectivity. Current methods of delineating cortical structures and their subregions are insufficient for in vivo applications, either being highly invasive or requiring a detailed knowledge of a region’s tuning properties. To address this, we seek to establish a structural biomarker capable of delineating the cortex that possesses a non-invasive correlate. We explore myelin as a potential candidate by evaluating its efficacy in parcellating the feline auditory cortex through the generation of depthwise myelin density profiles for each of the 13 auditory cortical subregions. Our analyses revealed significant …

Exogenous Surfactant As A Delivery Vehicle For Intrapulmonary Therapeutics, Brandon J. Baer

Electronic Thesis and Dissertation Repository

As an organ system, the lung has unique advantages and disadvantages for direct drug delivery. Its contact with the external environment allows for the airways to be easily accessible to intrapulmonary delivery. However, its complex structure, which divides into more narrow airways with each branch, can make direct delivery to the remote alveoli challenging. The objective of this thesis was to overcome this issue by using exogenous surfactant, a lipoprotein complex used to treat neonatal respiratory distress syndrome, as a carrier for pulmonary therapeutics. It was hypothesized that therapeutics administered with a surfactant vehicle would display enhanced delivery to the …

The Analysis Of Ginsenosides In Ginseng Garden Soil, Karina Marie Kaberi

Electronic Thesis and Dissertation Repository

American ginseng (Panax quinquefolius L.) produces natural products called ginsenosides. The biggest challenge Ontario commercial ginseng farmers face is ginseng replant disease. To understand the function of ginseng root exudates, ginsenoside accumulation and persistence over time were investigated. Currently, no reliable ginsenoside specific extraction method, characterizing the changes in soil chemistry exists. Ginsenoside extraction protocol optimization was required to determine how ginsenoside composition changed over time. Overall, protocol optimization resulted in a 30% increase in yield of ginsenosides compared to previous extraction protocols. In the ginseng gardens, ginsenoside accumulation occurs slowly and did not reach significantly measurable amounts until the …

21°C Is The Emerging Ideal Temperature For Kidney Preservation In The Presence Of Hydrogen Sulfide, Smriti Juriasingani

Electronic Thesis and Dissertation Repository

Kidney transplantation is the treatment of choice for patients with end-stage kidney disease. However, the shortage of transplantable kidneys has led to ever-increasing waiting lists. As a result, kidneys obtained via donation after cardiac death (DCD) are being used more frequently for transplantation. However, they exhibit poorer outcomes due to ischemia-reperfusion injury (IRI) and cold preservation methods, such as static cold storage (SCS). Supplementing cold preservation solutions with hydrogen sulfide donors, such as AP39, has been shown to improve renal IRI and graft outcomes, but the injury associated with cold preservation remains. This thesis evaluates the effect of subnormothermic kidney …

Evaluating Anesthetic Protocols For Non-Human Primate Functional Neuroimaging, Megha Verma

Electronic Thesis and Dissertation Repository

Functional magnetic resonance imaging (fMRI) is a non-invasive technique that can be used to measure a proxy of neural activity in vivo with high spatial specificity. One subject can be followed for a long period of time to assess changes in functional brain organization. However, fMRI is extremely sensitive to motion. The challenges of training non-human primates to reduce motion in an MRI scanner motivate the study of anesthesia which is commonly used to substitute for this training. In this thesis, I compare three different commonly used anesthetic protocols: isoflurane, propofol-fentanyl in combination, and fentanyl alone, to test which of …

The Effects Of Maternal Delta-9-Tetrahydrocannabinol And Cannabidiol Exposure On Fetal Heart Development In Mice, Gregory Robinson

Electronic Thesis and Dissertation Repository

Up to 22.6% of pregnant women consume cannabis during pregnancy despite the uncertainty of teratogenicity of the main ingredients in cannabis, delta-9-tetrahydrocannabinol (THC) and cannabidiol (CBD). This study tested the hypothesis that gestational THC and CBD exposure leads to heart abnormalities. Daily, oral THC exposure induced heart abnormalities in 68% of offspring with three main phenotypes including thickened semilunar valves, ventricular myocardial hypertrophy and hypoplastic coronary arteries in fetuses, and postnatal cardiac dysfunction. Altered gene expression of key cardiogenic regulators, increased proliferation, and reduced epicardial epithelial-to-mesenchymal-transition were demonstrated implicating potential mechanisms responsible for these abnormalities. Also, maternal CBD exposure resulted …

Exploiting The Immunomodulatory Potentials Of Inkt Cells In Sepsis And Cancer., Joshua Choi

Electronic Thesis and Dissertation Repository

Invariant natural killer T (iNKT) cells are a unique unconventional T cell subset that recognize glycolipids presented by CD1d expressing cells. The prototypical glycolipid agonist of iNKT cells, α-Galactosylceramide (α-GalCer), can induce the rapid release of an arsenal of cytotoxic effector molecules and enormous amounts of immunomodulatory cytokines as early as two hours after activation. In addition to α-GalCer, various glycolipid agonists are available that allow for specific, in vivo targeting of iNKT cells, and can exert divergent T-helper (T_H)1 and/or T_H2 immune responses. Therefore, the type of response instigated by iNKT cells can profoundly influence …

Tracing Nutrient Sources To Lipid Production In Birds And Insects Using Stable Isotope (Δ13c, Δ2h) Tracers: Implications For Nutritional Physiology Of Migratory Species, Libesha Anparasan

Electronic Thesis and Dissertation Repository

Using stable isotope measurements of inert tissues to determine origins and migratory patterns is well established. However, isotopically determining nutritional origins of lipids, the primary fuel of migration, has not been attempted. I explored isotopic links between diet and stored lipids in captive White-throated Sparrows (Zonotrichia albicollis) and true armyworm moths (Mythimna unipuncta) using δ¹³C and δ²H measurements. Isotopic discrimination between body lipids and diet was established as linear calibration functions. Isotopic uptake following a diet switch in moths was used to trace lipid accumulation over time. Isotopic correlations between breath metabolic …

In Search Of Psychiatric Kinds: Natural Kinds And Natural Classification In Psychiatry, Nicholas Slothouber

Electronic Thesis and Dissertation Repository

In recent years both philosophers and scientists have asked whether or not our current kinds of mental disorder—e.g., schizophrenia, depression, bipolar disorder—are natural kinds; and, moreover, whether or not the search for natural kinds of mental disorder is a realistic desideratum for psychiatry. In this dissertation I clarify the sense in which a kind can be said to be “natural” or “real” and argue that, despite a few notable exceptions, kinds of mental disorder cannot be considered natural kinds. Furthermore, I contend that psychopathological phenomena do not cluster together into kinds in the way that paradigmatic natural kinds (e.g., chemical …

Maternal Nicotine Exposure Induces Congenital Heart Defects In The Offspring Of Mice, Elizabeth Greco

Electronic Thesis and Dissertation Repository

Congenital heart defects are the most prevalent birth defect, and maternal cigarette smoking is a known risk factor. Nicotine replacement therapies are recommended to pregnant women who smoke to aid in smoking cessation, as this alternative is thought to be much safer compared to cigarette smoking. However, these products contain nicotine, and the safety of nicotine on the developing heart is not well known. In this thesis, a mouse model was used to test the hypothesis that maternal nicotine exposure (MNE) during pregnancy leads to congenital heart defects and coronary artery defects in the offspring of mice. MNE resulted in …

Cannabinoid Transmission In The Basolateral Amygdala Modulates Prefrontal Cortex And Ventral Hippocampal Activity, Brian J. Pereira

Electronic Thesis and Dissertation Repository

The cannabinoid system is important for maintaining neuron-to-neuron communication within the mammalian brain. One of the most commonly used substances to alter the cannabinoid system is cannabis. Individuals who are exposed to cannabis report having dissociable effects; both positive and negative. High amounts of THC have been commonly associated with the negative effects of cannabis, whereas CBD can be used to counter these. Pre-clinical evidence suggests that the combination of the two compounds can produce a therapeutic benefit for individuals who are susceptible to the effects of THC. The present study investigates whether the combination of THC+CBD can prevent electrophysiological …

The Role Of Cholinergic Signaling In Cardiac Function, Rachel Reingold

Electronic Thesis and Dissertation Repository

Cardiovascular disease is one of the leading causes of death in Canada. Treatment currently focuses on preventing the increase of sympathetic signaling seen in heart failure. However, it has recently been noted that cardiac function is dependent on parasympathetic tone. Previous studies have demonstrated the development of heart failure when cholinergic targets are knocked out in cardiomyocytes. Transgenic mouse models that have increased cholinergic transmission show protection against cardiovascular insults. We have shown that transgenic mice overexpressing vesicular acetylcholine transporter in cholinergic cells show cardiovascular protection in response to ex vivo insults. As well, this protection is seen when cholinergic …

Measurement And Protection Of Lung Health In Poultry Farmers Of Southwestern Ontario, Rose-Marie Doyon Dolinar

Electronic Thesis and Dissertation Repository

Chronic obstructive lung disease (COPD), develops gradually, and tends to be noticed by farmers only after there has been a significant loss of lung function. People with symptoms of COPD often present for health care in later stages of disease, because they accept cough or breathlessness as “normal”.

Measurement of lung health for those at risk of developing COPD provides an opportunity for early detection of lung disease, and deter the progression toward irreversible damage to the lungs. COPD is, however, under-diagnosed.

The importance of bringing primary care providers and farmers together, and acknowledging the high-risk nature of occupational exposures, …

Amelioration Of Prenatal Alcohol Effects By Environmental Enrichment In A Mouse Model Of Fasd, Aniruddho Chokroborty-Hoque

Electronic Thesis and Dissertation Repository

Maternal alcohol consumption during pregnancy results in a spectrum of behavioural and cognitive deficits collectively known as Fetal Alcohol Spectrum Disorders (FASD). Currently, little is know about if and how the external environment may modulate these deficits. I have used C57BL/6 mice to study this interaction between prenatal alcohol exposure and the postnatal environment. Alcohol exposure during synaptogenesis produces high levels of anxiety-like traits and decreased memory performance. Alcohol-exposed mice (and matched unexposed controls) were put in 'environmentally-enriched' conditions of voluntary exercise, physical activities and cognitive stimulation to ascertain the effects of a positive postnatal environment. The results show that …

Characterization Of An 18f-Growth Hormone Secretagogue Probe For Positron Emission Tomography Imaging Of The Growth Hormone Secretagogue Receptor, Ahmed Abbas

Electronic Thesis and Dissertation Repository

Cardiovascular disease affects 1.6 million Canadians, of whom one-third have heart failure (HF). HF is diagnosed by imaging investigations and detection of circulating biomarkers. Most of the current imaging strategies study morphologic and gross functional changes, but fall short of imaging molecular abnormalities associated with HF. Biomarkers offer molecular targets; however, clinical biomarkers circulate systemically and are not cardiac-specific. Thus, there is critical need for a biomarker that is endogenous to myocardial tissues. The growth hormone secretagogue receptor 1a (GHSR1a), which binds the hormone ghrelin, is expressed by cardiomyocytes and is elevated in HF patients. This study characterized the specificity …