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The elaborate signals of animals are often costly to produce and maintain, thus communicating reliable information about the quality of an individual to potential mates or competitors. The properties of the sensory systems that receive signals can drive the evolution of these signals and shape their form and function. However, relatively little is known about the ecological and physiological constraints that may influence the development and maintenance of sensory systems. In the house finch (Carpodacus mexicanus) and many other bird species, carotenoid pigments are used to create colorful sexually selected displays, and their expression is limited by health and dietary access to carotenoids. Carotenoids also accumulate in the avian retina, protecting it from photodamage and tuning color vision. Analogous to plumage carotenoid accumulation, I hypothesized that avian vision is subject to environmental and physiological constraints imposed by the acquisition and allocation of carotenoids. To test this hypothesis, I carried out a series of field and captive studies of the house finch to assess natural variation in and correlates of retinal carotenoid accumulation and to experimentally investigate the effects of dietary carotenoid availability, immune activation, and light exposure on retinal carotenoid accumulation. Moreover, through dietary manipulations of retinal carotenoid accumulation, I tested the impacts of carotenoid accumulation on visually mediated foraging and mate choice behaviors. My results indicate that avian retinal carotenoid accumulation is variable and significantly influenced by dietary carotenoid availability and immune system activity. Behavioral studies suggest that retinal carotenoid accumulation influences visual foraging performance and mediates a trade-off between color discrimination and photoreceptor sensitivity under dim-light conditions. Retinal accumulation did not influence female choice for male carotenoid-based coloration, indicating that a direct link between retinal accumulation and sexual selection for coloration is unlikely. However, retinal carotenoid accumulation in males was positively correlated with their plumage coloration. Thus, carotenoid-mediated visual health and performance or may be part of the information encoded in sexually selected coloration.
ContributorsToomey, Matthew (Author) / McGraw, Kevin J. (Thesis advisor) / Deviche, Pierre (Committee member) / Smith, Brian (Committee member) / Rutowski, Ronald (Committee member) / Verrelli, Brian (Committee member) / Arizona State University (Publisher)
Created2011
Description
Concurrent with the epidemic of childhood obesity (17% of adolescents), an unprecedented world-wide increase in the prevalence of several adiposity-related complications (including fatty liver disease (hepatic steatosis), type 2 diabetes and early cardiovascular disorders) in this age group, has emerged. Two principle environmental variables play an essential role in the development and maintenance of obesity and in disturbing glucose homeostasis: a lack of physical exercise and overnutrition, i.e., high carbohydrate and high fat diets (HFD). It was our laboratory's intention to develop a rodent model to examine whether the metabolic instability observed in human pubertal children is also present in maturing rats and whether a HFD during this maturational period enhances adipose-related complications with or without an increase in body weight. We hypothesized that maturing Sprague-Dawley rats would reveal a profile of metabolic disturbances and that a disruption of the hyperbolic arrangement between insulin sensitivity and insulin release would be evident (statistically significant changes in fasting hyperinsulinemia, insulin resistance, and insulin release) indicating a high risk environment for future cardiometabolic diseases. It was observed that pubertal rats are metabolically impaired and that a HFD substantially enhances metabolic deficits with marked disturbance in insulin sensitivity (hyperinsulinemia). Additionally, substantial lipogenesis was observed in visceral and liver tissue, potentially as a result of hyperinsulinemia. Both phenotypes of maturing rats exposed to a HFD (obesity prone and obesity resistant) demonstrated "metabolic obesity" regardless of physical phenotype. These outcomes have relevance in the context of public health, particularly if lipocentricity is viewed as an essential element in the challenge of preventing and/or treating perturbations to the metabolic health of pubertal children.
ContributorsSmith, John Clark (Author) / Caplan, Michael (Thesis director) / Herman, Richard (Committee member) / Barrett, The Honors College (Contributor) / Harrington Bioengineering Program (Contributor)
Created2014-05
Description
In a world in which technologies proliferate at a rapid rate, it is no surprise that the medical device industry has grown in leaps and bounds. This surge in medical technology, especially implantable medical technology, has altered the modern operating room, transforming surgery from a technique-driven activity into a technology-driven profession. This reliance upon technologies has fostered close ties between physicians and the medical device industry and within this relationship, medical device representatives play an integral role. This paper will investigate the relationship that exists between physicians and the medical device industry along with the potential conflicts of interest that may result due to this relationship. I will focus in particular on orthopedic medical devices due to media attention as a result of a 2007 Department of Justice settlement involving the leading orthopedic companies. This case proved instrumental in highlighting previously unknown instances in which conflicts of interest were occurring in the medical device industry.
ContributorsLove, Kailey (Author) / Robert, Jason (Thesis director) / Marchant, Gary (Committee member) / Buchholtz, Stephanie (Committee member) / Barrett, The Honors College (Contributor) / School of International Letters and Cultures (Contributor) / School of Life Sciences (Contributor) / School for the Science of Health Care Delivery (Contributor)
Created2014-05
Description
Millions of Americans live with motor impairments resulting from a stroke and the best way to administer rehabilitative therapy to achieve recovery is not well understood. Adaptive mixed reality rehabilitation (AMRR) is a novel integration of motion capture technology and high-level media computing that provides precise kinematic measurements and engaging multimodal feedback for self-assessment during a therapeutic task. The AMRR system was evaluated in a small (N=3) cohort of stroke survivors to determine best practices for administering adaptive, media-based therapy. A proof of concept study followed, examining changes in clinical scale and kinematic performances among a group of stroke survivors who received either a month of AMRR therapy (N = 11) or matched dosing of traditional repetitive task therapy (N = 10). Both groups demonstrated statistically significant improvements in Wolf Motor Function Test and upper-extremity Fugl-Meyer Assessment scores, indicating increased function after the therapy. However, only participants who received AMRR therapy showed a consistent improvement in their kinematic measurements, including those measured in the trained reaching task (reaching to grasp a cone) and in an untrained reaching task (reaching to push a lighted button). These results suggest that that the AMRR system can be used as a therapy tool to enhance both functionality and reaching kinematics that quantify movement quality. Additionally, the AMRR concepts are currently being transitioned to a home-based training application. An inexpensive, easy-to-use, toolkit of tangible objects has been developed to sense, assess and provide feedback on hand function during different functional activities. These objects have been shown to accurately and consistently track hand function in people with unimpaired movements and will be tested with stroke survivors in the future.
ContributorsDuff, Margaret Rose (Author) / Rikakis, Thanassis (Thesis advisor) / He, Jiping (Thesis advisor) / Herman, Richard (Committee member) / Kleim, Jeffrey (Committee member) / Santos, Veronica (Committee member) / Towe, Bruce (Committee member) / Arizona State University (Publisher)
Created2012
Description
Glioblastoma (GBM) is the most common primary brain tumor with an incidence of approximately 11,000 Americans. Despite decades of research, average survival for GBM patients is a modest 15 months. Increasing the extent of GBM resection increases patient survival. However, extending neurosurgical margins also threatens the removal of eloquent brain. For this reason, the infiltrative nature of GBM is an obstacle to its complete resection. We hypothesize that targeting genes and proteins that regulate GBM motility, and developing techniques that safely enhance extent of surgical resection, will improve GBM patient survival by decreasing infiltration into eloquent brain regions and enhancing tumor cytoreduction during surgery. Chapter 2 of this dissertation describes a gene and protein we identified; aquaporin-1 (aqp1) that enhances infiltration of GBM. In chapter 3, we describe a method for enhancing the diagnostic yield of GBM patient biopsies which will assist in identifying future molecular targets for GBM therapies. In chapter 4 we develop an intraoperative optical imaging technique that will assist identifying GBM and its infiltrative margins during surgical resection. The topic of this dissertation aims to target glioblastoma infiltration from molecular and cellular biology and neurosurgical disciplines. In the introduction we; 1. Provide a background of GBM and current therapies. 2. Discuss a protein we found that decreases GBM survival. 3. Describe an imaging modality we utilized for improving the quality of accrued patient GBM samples. 4. We provide an overview of intraoperative contrast agents available for neurosurgical resection of GBM, and discuss a new agent we studied for intraoperative visualization of GBM.
ContributorsGeorges, Joseph F (Author) / Feuerstein, Burt G (Thesis advisor) / Smith, Brian H. (Thesis advisor) / Van Keuren-Jensen, Kendall (Committee member) / Deviche, Pierre (Committee member) / Bennett, Kevin (Committee member) / Arizona State University (Publisher)
Created2014
Description
Colorful ornaments in animals often serve as sexually selected signals of quality. While pigment-based colors are well-studied in these regards, structural colors that result from the interaction of light with photonic nanostructures are comparatively understudied in terms of their consequences in social contexts, their costs of production, and even the best way to measure them. Iridescent colors are some of the most brilliant and conspicuous colors in nature, and I studied the measurement, condition-dependence, and signaling role of iridescence in Anna's hummingbirds (Calypte anna). While most animal colors are easily quantified using well-established spectrophotometric techniques, the unique characteristics of iridescent colors present challenges to measurement and opportunities to quantify novel color metrics. I designed and tested an apparatus for careful control and measurement of viewing geometry and highly repeatable measurements. These measurements could be used to accurately characterize individual variation in iridescent Anna's hummingbirds to examine their condition-dependence and signaling role. Next, I examined the literature published to date for evidence of condition-dependence of structural colors in birds. Using meta-analyses, I found that structural colors of all three types - white, ultra-violet/blue, and iridescence - are significantly condition-dependent, meaning that they can convey information about quality to conspecifics. I then investigated whether iridescent colors were condition-dependent in Anna's hummingbirds both in a field correlational study and in an experimental study. Throughout the year, I found that iridescent feathers in both male and female Anna's hummingbirds become less brilliant as they age. Color was not correlated with body condition in any age/sex group. However, iridescent coloration in male Anna's hummingbirds was significantly affected by experimental protein in the diet during feather growth, indicating that iridescent color may signal diet quality. Finally, I examined how iridescent colors were used to mediate social competitions in male and female Anna's hummingbirds. Surprisingly, males that were less colorful won significantly more contests than more colorful males, and colorful males received more aggression. Less colorful males may be attempting to drive away colorful neighbors that may be preferred mates. Female iridescent ornament size and color was highly variable, but did not influence contest outcomes or aggression.
ContributorsMeadows, Melissa (Author) / McGraw, Kevin J. (Thesis advisor) / Rutowski, Ronald L (Committee member) / Sabo, John L (Committee member) / Alcock, John (Committee member) / Deviche, Pierre (Committee member) / Arizona State University (Publisher)
Created2012
Description
Conditions during development can shape the expression of traits at adulthood, a phenomenon called developmental plasticity. In this context, factors such as nutrition or health state during development can affect current and subsequent physiology, body size, brain structure, ornamentation, and behavior. However, many of the links between developmental and adult phenotype are poorly understood. I performed a series of experiments using a common molecular currency - carotenoid pigments - to track somatic and reproductive investments through development and into adulthood. Carotenoids are red, orange, or yellow pigments that: (a) animals must acquire from their diets, (b) can be physiologically beneficial, acting as antioxidants or immunostimulants, and (c) color the sexually attractive features (e.g., feathers, scales) of many animals. I studied how carotenoid nutrition and immune challenges during ontogeny impacted ornamental coloration and immune function of adult male mallard ducks (Anas platyrhynchos). Male mallards use carotenoids to pigment their yellow beak, and males with more beaks that are more yellow are preferred as mates, have increased immune function, and have higher quality sperm. In my dissertation work, I established a natural context for the role that carotenoids and body condition play in the formation of the adult phenotype and examined how early-life experiences, including immune challenges and dietary access to carotenoids, affect adult immune function and ornamental coloration. Evidence from mallard ducklings in the field showed that variation in circulating carotenoid levels at hatch are likely driven by maternal allocation of carotenoids, but that carotenoid physiology shifts during the subsequent few weeks to reflect individual foraging habits. In the lab, adult beak color expression and immune function were more tightly correlated with body condition during growth than body condition during subsequent stages of development or adulthood. Immune challenges during development affected adult immune function and interacted with carotenoid physiology during adulthood, but did not affect adult beak coloration. Dietary access to carotenoids during development, but not adulthood, also affected adult immune function. Taken together, these results highlight the importance of the developmental stage in shaping certain survival-related traits (i.e., immune function), and lead to further questions regarding the development of ornamental traits.
ContributorsButler, Michael (Author) / McGraw, Kevin J. (Thesis advisor) / Chang, Yung (Committee member) / Deviche, Pierre (Committee member) / DeNardo, Dale (Committee member) / Rutowski, Ronald (Committee member) / Arizona State University (Publisher)
Created2012
Description
Parental care provides many benefits to offspring. One widely realized benefit is enhanced regulation of offspring's thermal environment. The developmental thermal environment during development can be optimized behaviorally through nest site selection and brooding, and it can be further enhanced by physiological heat production. In fact, enhancement of the developmental thermal environment has been proposed as the initial driving force for the evolution of endothermy in bird and mammals. I used pythons (Squamata: Pythonidae) to expand existing knowledge of behavioral and physiological parental tactics used to regulate offspring thermal environment. I first demonstrated that brooding behavior in the Children's python (Antaresia childreni) is largely driven by internal mechanisms, similar to solitary birds, suggesting that the early evolution of the parent-offspring association was probably hormonally driven. Two species of python are known to be facultatively thermogenic (i.e., are endothermic during reproduction). I expand current knowledge of thermogenesis in Burmese pythons (Python molurus) by demonstrating that females use their own body temperature to modulate thermogenesis. Although pythons are commonly cited as thermogenic, the actual extent of thermogenesis within the family Pythonidae is unknown. Thus, I assessed the thermogenic capability of five previously unstudied species of python to aid in understanding phylogenetic, morphological, and distributional influences on thermogenesis in pythons. Results suggest that facultative thermogenesis is likely rare among pythons. To understand why it is rare, I used an artificial model to demonstrate that energetic costs to the female likely outweigh thermal benefits to the clutch in species that do not inhabit cooler latitudes or lack large energy reserves. In combination with other studies, these results show that facultative thermogenesis during brooding in pythons likely requires particular ecological and physiological factors for its evolution.
ContributorsBrashears, Jake (Author) / DeNardo, Dale (Thesis advisor) / Harrison, Jon (Committee member) / Deviche, Pierre (Committee member) / McGraw, Kevin (Committee member) / Smith, Andrew (Committee member) / Arizona State University (Publisher)
Created2012
Description
Though for most of the twentieth century, dogma held that the adult brain was post-mitotic, it is now known that adult neurogenesis is widespread among vertebrates, from fish, amphibians, reptiles and birds to mammals including humans. Seasonal changes in adult neurogenesis are well characterized in the song control system of song birds, and have been found in seasonally breeding mammals as well. In contrast to more derived vertebrates, such as mammals, where adult neurogenesis is restricted primarily to the olfactory bulb and the dentate gyrus of the hippocampus, neurogenesis is widespread along the ventricles of adult amphibians. I hypothesized that seasonal changes in adult amphibian brain cell proliferation and survival are a potential regulator of reproductive neuroendocrine function. Adult, male American bullfrogs (Rana catesbeiana; aka Lithobates catesbeianus), were maintained in captivity for up to a year under season-appropriate photoperiod. Analysis of hormone levels indicated seasonal changes in plasma testosterone concentration consistent with field studies. Using the thymidine analogue 5-bromo-2-deoxyuridine (BrdU) as a marker for newly generated cells, two differentially regulated aspects of brain cell neogenesis were tracked; that is, proliferation and survival. Seasonal differences were found in BrdU labeling in several brain areas, including the olfactory bulb, medial pallium, nucleus accumbens and the infundibular hypothalamus. Clear seasonal differences were also found in the pars distalis region of the pituitary gland, an important component of neuroendocrine pathways. BrdU labeling was also examined in relation to two neuropeptides important for amphibian reproduction: arginine vasotocin and gonadotropin releasing hormone. No cells co-localized with BrdU and either neuropeptide, but new born cells were found in close proximity to neuropeptide-containing neurons. These data suggest that seasonal differences in brain and pituitary gland cell neogenesis are a potential neuroendocrine regulatory mechanism.
ContributorsMumaw, Luke (Author) / Orchinik, Miles (Thesis advisor) / Deviche, Pierre (Committee member) / Chandler, Douglas (Committee member) / Arizona State University (Publisher)
Created2012
Description
Background: Both puberty and diets composed of high levels of saturated fats have been shown to result in central adiposity, fasting hyperinsulinemia, insulin resistance and impaired glucose tolerance. While a significantly insulinogenic phenotypic change occurs in these two incidences, glucose homeostasis does not appear to be affected. Methods: Male, Sprague-dawley rats were fed diets consisting of CHOW or low fat (LF), High Fat Diet and High Fat Diet (HFD) with supplementary Canola Oil (Monounsaturated fat). These rats were given these diets at 4-5 weeks old and given intraperitoneal and oral glucose tolerance tests(IPGTT; OGTT) at 4 and 8 weeks to further understand glucose and insulin behavior under different treatments. (IPGTT: LF-n=14, HFD-n=16, HFD+CAN-n=12; OGTT: LF-n=8, HFD-n=8, HFD+CAN-n=6). Results: When comparing LF fed rats at 8 weeks with 4 week glucose challenge test, area under the curve (AUC) of glucose was 1.2 that of 4 weeks. At 8 weeks, HFD fed rats AUCg was much greater than LF fed rats under both IPGTT and OGTT. When supplemented with Canola oil, HFD fed rats AUC returned to LF data range. Despite the alleviating glucose homeostasis affects of Canola oil the AUC of insulin curve, which was elevated by HFD, remained high. Conclusion: HFD in maturing rats elevates fasting insulin levels, increases insulin resistance and lowers glucose homeostasis. When given a monounsaturated fatty acid (MUFA) supplement fasting hyperinsulinemia, and late hyperinsulinemia still occur though glucose homeostasis is regained. For OGTT HFD also induced late hyper c-peptide levels and compared to LF and HFD+CAN, a higher c-peptide level over time.
ContributorsRay, Tyler John (Author) / Caplan, Michael (Thesis director) / Herman, Richard (Committee member) / Towner, Kali (Committee member) / Barrett, The Honors College (Contributor) / Department of Chemistry and Biochemistry (Contributor) / W. P. Carey School of Business (Contributor) / School of Human Evolution and Social Change (Contributor)
Created2015-05