Theses and dissertations

This collection includes both ASU Theses and Dissertations, submitted by graduate students, and the Barrett, Honors College theses submitted by undergraduate students. 

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Hyperinsulinemia

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…

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
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Drug Release from in \u2014 situ gelling material

Description
The main goal of this project was to study and understand the release of gentamicin from in – situ, self – reactive drug delivery gelling matrix. The motivation behind this was to create a drug delivery mechanism for gentamicin and eliminate the need for re–injecting the drug multiple times into…

The main goal of this project was to study and understand the release of gentamicin from in – situ, self – reactive drug delivery gelling matrix. The motivation behind this was to create a drug delivery mechanism for gentamicin and eliminate the need for re–injecting the drug multiple times into the patient. Gentamicin is used to treat various different bacterial infections of the central nervous system, blood, kidneys, gall bladder, bile duct, heart cavity linings, and heart valves. Pentaerythritol–tetrakis
(3 – mercaptoproprionate; QT) was crosslinked with poly(ethylene glycol) diacrylate (PEGDA) having an average molecular weight of 575 with the help of Phosphate Buffer Saline (PBS), with a buffer ionic strength of 0.143M and a pH of 8.9 and 11, for the drug concentrations of 5 mg/mL and 50 mg/mL, respectively. The Michael – type reaction formed the crosslinked self – administering gelling matrix. With the gelling matrix starting to coagulate into a hydrophobic solid in about 5 minutes, the material was injected into Tygon tubing. After complete solidification, the drug – loaded gels were extracted from the tubing and divided into 1 cm cylinders. The cylinders with 5mg/mL and 50mg/mL drug concentration exhibited a sustained and controlled release curve for about 288 hours. This project as well as this drug delivery system can in the future be expanded for use in the delivery of more hydrophobic long – term drugs to the patient.
ContributorsJolly, Nehal (Author) / Vernon, Brent (Thesis director) / Herman, Richard (Committee member) / Harrington Bioengineering Program (Contributor) / Barrett, The Honors College (Contributor)
Created2016-05