Matching Items (81)
Description
Noninvasive neuromodulation could help treat many neurological disorders, but existing techniques have low resolution and weak penetration. Ultrasound (US) shows promise for stimulation of smaller areas and subcortical structures. However, the mechanism and parameter design are not understood. US can stimulate tail and hindlimb movements in rats, but not forelimb, for unknown reasons. Potentially, US could also stimulate peripheral or enteric neurons for control of blood glucose.
To better understand the inconsistent effects across rat motor cortex, US modulation of electrically-evoked movements was tested. A stimulation array was implanted on the cortical surface and US (200 kHz, 30-60 W/cm2 peak) was applied while measuring changes in the evoked forelimb and hindlimb movements. Direct US stimulation of the hindlimb was also studied. To test peripheral effects, rat blood glucose levels were measured while applying US near the liver.
No short-term motor modulation was visible (95% confidence interval: -3.5% to +5.1% forelimb, -3.8% to +5.5% hindlimb). There was significant long-term (minutes-order) suppression (95% confidence interval: -3.7% to -10.8% forelimb, -3.8% to -11.9% hindlimb). This suppression may be due to the considerable heating (+1.8°C between US
on-US conditions); effects of heat and US were not separable in this experiment. US directly evoked hindlimb and scrotum movements in some sessions. This required a long interval, at least 3 seconds between US bursts. Movement could be evoked with much shorter pulses than used in literature (3 ms). The EMG latency (10 ms) was compatible with activation of corticospinal neurons. The glucose modulation test showed a strong increase in a few trials, but across all trials found no significant effect.
The single motor response and the long refractory period together suggest that only the beginning of the US burst had a stimulatory effect. This would explain the lack of short-term modulation, and suggests future work with shorter pulses could better explore the missing forelimb response. During the refractory period there was no change in the electrically-evoked response, which suggests the US stimulation mechanism is independent of normal brain activity. These results challenge the literature-standard protocols and provide new insights on the unknown mechanism.
To better understand the inconsistent effects across rat motor cortex, US modulation of electrically-evoked movements was tested. A stimulation array was implanted on the cortical surface and US (200 kHz, 30-60 W/cm2 peak) was applied while measuring changes in the evoked forelimb and hindlimb movements. Direct US stimulation of the hindlimb was also studied. To test peripheral effects, rat blood glucose levels were measured while applying US near the liver.
No short-term motor modulation was visible (95% confidence interval: -3.5% to +5.1% forelimb, -3.8% to +5.5% hindlimb). There was significant long-term (minutes-order) suppression (95% confidence interval: -3.7% to -10.8% forelimb, -3.8% to -11.9% hindlimb). This suppression may be due to the considerable heating (+1.8°C between US
on-US conditions); effects of heat and US were not separable in this experiment. US directly evoked hindlimb and scrotum movements in some sessions. This required a long interval, at least 3 seconds between US bursts. Movement could be evoked with much shorter pulses than used in literature (3 ms). The EMG latency (10 ms) was compatible with activation of corticospinal neurons. The glucose modulation test showed a strong increase in a few trials, but across all trials found no significant effect.
The single motor response and the long refractory period together suggest that only the beginning of the US burst had a stimulatory effect. This would explain the lack of short-term modulation, and suggests future work with shorter pulses could better explore the missing forelimb response. During the refractory period there was no change in the electrically-evoked response, which suggests the US stimulation mechanism is independent of normal brain activity. These results challenge the literature-standard protocols and provide new insights on the unknown mechanism.
ContributorsGulick, Daniel Withers (Author) / Kleim, Jeffrey (Thesis advisor) / Towe, Bruce (Thesis advisor) / Muthuswamy, Jitendran (Committee member) / Herman, Richard (Committee member) / Helms Tillery, Steven (Committee member) / Arizona State University (Publisher)
Created2015
Description
Cardiovascular disease and diabetes are major health burdens. Diabetes is a primary risk factor of cardiovascular disease, and there is a strong link between obesity and risk of developing diabetes. With the prevalence of prediabetes highest among overweight/obese individuals, investigation into preventative strategies are needed. Aerobic exercise is a potent stimulus for both insulin and non-insulin dependent glucose uptake into the skeletal muscle. A single exercise session can improve insulin sensitivity within hours after exercise. The effects of intensity, type, and volume of exercise on glucose homeostasis have been studied extensively; however, controlling for muscle contraction frequency with a constant exercise intensity and workload has not been examined. The purpose of this study was to compare muscle contraction frequency during aerobic exercise by altering cycling cadence on insulin sensitivity and vascular health. Eleven obese males (age=28yr, BMI=35kg/m2) completed three conditions in random order: 1) control-no exercise; 2) 45-min cycling at 45 revolutions per minute (45RPM) at 65-75%VO2max; 3) 45-min cycling at 90RPM at 65-75%VO2max. Glucose control and insulin sensitivity were assessed with oral glucose tolerance tests (OGTT) 4 hours post-exercise. Vascular health was assessed via flow-mediated dilation (FMD) pre-exercise, 1-hr and 2-hr post exercise and ambulatory blood pressure was assessed pre-exercise, and continually every 15 min post-exercise. Linear mixed models were used to compare the mean differences in outcome variables. There were no significant differences found between control and both exercise conditions for all OGTT outcomes and no differences were found between control and exercise in FMD (all, p>0.05). Significant effects for exercise were found for both brachial and central blood pressure measures. Brachial systolic blood pressures were lower at 2- and 4-hr post-exercise by approximately -10 and -8mmHg, respectively (p<0.001 and p=0.004) versus control. Central systolic blood pressures were lower at 2-, 3-, and 4-hr post-exercise by approximately -8, -9 and -6mmHg, respectively (p<0.001, p=0.021 and p=0.004) versus control. In conclusion, aerobic exercise, regardless of muscle contraction frequency, were unable to effect glucose control and insulin sensitivity. Similarly, there was no effect on vascular function. However, there was a significant effect of aerobic exercise on reducing post-exercise blood pressure.
ContributorsJarrett, Catherine Lee (Author) / Gaesser, Glenn A (Thesis advisor) / Angadi, Siddhartha S (Committee member) / Dickinson, Jared M (Committee member) / Whisner, Corrie M (Committee member) / Todd, Michael W (Committee member) / Arizona State University (Publisher)
Created2017
Description
Diabetes is a disease characterized by reduced insulin action and secretion, leading to elevated blood glucose. In the 1990s, studies showed that intravenous injection of fatty acids led to a sharp negative response in insulin action that subsided hours after the injection. The molecule associated with diminished insulin signalling response was a byproduct of fatty acids, diacylglycerol. This dissertation is focused on the formulation of a model built around the known mechanisms of glucose and fatty acid storage and metabolism within myocytes, as well as downstream effects of diacylglycerol on insulin action. Data from euglycemic-hyperinsulinemic clamp with fatty acid infusion studies are used to validate the qualitative behavior of the model and estimate parameters. The model closely matches clinical data and suggests a new metric to determine quantitative measurements of insulin action downregulation. Analysis and numerical simulation of the long term, piecewise smooth system of ordinary differential equations demonstrates a discontinuous bifurcation implicating nutrient excess as a driver of muscular insulin resistance.
ContributorsBurkow, Daniel Harrison (Author) / Li, Jiaxu (Thesis advisor) / Castillo-Chavez, Carlos (Thesis advisor) / Kuang, Yang (Committee member) / Holechek, Susan (Committee member) / Arizona State University (Publisher)
Created2017
Description
Diabetes is becoming a serious problem in China. At the same time, China’s medical
system has faced a difficult situation because of the lack of medical resources and the unequal medical resource distribution between the BHs and BLHs. BH doctors are tremendously busy with both serious and minor illnesses while BLH medical providers are worried about a sufficient source of patients. This study aims to find the potential feasibility of a new service model in managing diabetes which will solve these medical problems. The study was conducted using an extensive literature review in addition to employing an interview and survey method to explore the perception and current situation in workload and income of medical providers from one BH and one BLH in China. Furthermore, this study tried to understand the acceptance of online medical technology in these medical provider groups. The results showed that doctors in the BH do not have the time needed to engage in extra work. This population is not satisfied with their work responsibilities and income structure. They want to engage in diagnosing and prescribing tasks, with respect to diabetes management. They would like to distribute the management work to BLH. On the other hand, medical providers in BLH have extra time and enthusiasm in doing extra work to improve their income. They are not satisfied with their workload and income, and want to change it. BLHs are willing to do the management work assisting the BH doctors. Additionally, the study showed that online medical technology requires a broader user education for medical providers from both big and BLHs. The conclusion can be summarized as design research advice for future service design in healthcare management. The proposed online medical service should meet different level medical providers' position and requirements regarding time, payment, and value. BH doctors are more suitable for diagnosing and prescribing and BLH medical providers are more suitable for follow-up service. This service should reflect the value of the BH doctors' professional service and the value of BLH medical providers' health management service. (discuss how design can improve this situation through app development)
system has faced a difficult situation because of the lack of medical resources and the unequal medical resource distribution between the BHs and BLHs. BH doctors are tremendously busy with both serious and minor illnesses while BLH medical providers are worried about a sufficient source of patients. This study aims to find the potential feasibility of a new service model in managing diabetes which will solve these medical problems. The study was conducted using an extensive literature review in addition to employing an interview and survey method to explore the perception and current situation in workload and income of medical providers from one BH and one BLH in China. Furthermore, this study tried to understand the acceptance of online medical technology in these medical provider groups. The results showed that doctors in the BH do not have the time needed to engage in extra work. This population is not satisfied with their work responsibilities and income structure. They want to engage in diagnosing and prescribing tasks, with respect to diabetes management. They would like to distribute the management work to BLH. On the other hand, medical providers in BLH have extra time and enthusiasm in doing extra work to improve their income. They are not satisfied with their workload and income, and want to change it. BLHs are willing to do the management work assisting the BH doctors. Additionally, the study showed that online medical technology requires a broader user education for medical providers from both big and BLHs. The conclusion can be summarized as design research advice for future service design in healthcare management. The proposed online medical service should meet different level medical providers' position and requirements regarding time, payment, and value. BH doctors are more suitable for diagnosing and prescribing and BLH medical providers are more suitable for follow-up service. This service should reflect the value of the BH doctors' professional service and the value of BLH medical providers' health management service. (discuss how design can improve this situation through app development)
ContributorsLiu, Maozhen (Author) / Takamura, John (Thesis advisor) / Doebbeling, Bradley (Committee member) / Herring, Donald (Committee member) / Arizona State University (Publisher)
Created2018
Description
Monitoring complex diseases and their comorbidities requires accurate and convenient measurements of multiple biomarkers. However, many state-of-the-art bioassays not only require complicated and time-consuming procedures, but also measure only one biomarker at a time. This noncomprehensive single-biomarker monitoring, as well as the cost and complexity of these bioassays advocate for a simple, rapid multi-marker sensing platform suitable for point-of-care or self-monitoring settings. To address this need, diabetes mellitus was selected as the example complex disease, with dry eye disease and cardiovascular disease as the example comorbidities. Seven vital biomarkers from these diseases were selected to investigate the platform technology: lactoferrin (Lfn), immunoglobulin E (IgE), insulin, glucose, lactate, low density lipoprotein (LDL), and high density lipoprotein (HDL). Using electrochemical techniques such as amperometry and electrochemical impedance spectroscopy (EIS), various single- and dual-marker sensing prototypes were studied. First, by focusing on the imaginary impedance of EIS, an analytical algorithm for the determination of optimal frequency and signal deconvolution was first developed. This algorithm helped overcome the challenge of signal overlapping in EIS multi-marker sensors, while providing a means to study the optimal frequency of a biomarker. The algorithm was then applied to develop various single- and dual-marker prototypes by exploring different kinds of molecular recognition elements (MRE) while studying the optimal frequencies of various biomarkers with respect to their biological properties. Throughout the exploration, 5 single-marker biosensors (glucose, lactate, insulin, IgE, and Lfn) and one dual-marker (LDL and HDL) biosensor were successfully developed. With the aid of nanoparticles and the engineering design of experiments, the zeta potential, conductivity, and molecular weight of a biomarker were found to be three example factors that contribute to a biomarker’s optimal frequency. The study platforms used in the study did not achieve dual-enzymatic marker biosensors (glucose and lactate) due to signal contamination from localized accumulation of reduced electron mediators on self-assembled monolayer. However, amperometric biosensors for glucose and lactate with disposable test strips and integrated samplers were successfully developed as a back-up solution to the multi-marker sensing platform. This work has resulted in twelve publications, five patents, and one submitted manuscripts at the time of submission.
ContributorsLin, Chi En (Author) / La Belle, Jeffrey T (Thesis advisor) / Caplan, Michael (Committee member) / Cook, Curtiss B (Committee member) / Stabenfeldt, Sarah (Committee member) / Spano, Mark (Committee member) / Arizona State University (Publisher)
Created2018
Description
Brown adipose tissue (BAT) is thought to be important in combating obesity as it can expend energy in the form of heat, e.g. thermogenesis. The goal of this study was to study the effect of injected norepinephrine (NE) on the activation of BAT in rats that were fed a high fat diet (HFD). A dose of 0.25 mg/kg NE was used to elicit a temperature response that was measured using transponders inserted subcutaneously over the BAT and lower back and intraperitoneally to measure the core temperature. The results found that the thermic effect of the BAT increased after the transition from low fat diet to a high fat diet (LFD) yet, after prolonged exposure to the HFD, the effects resembled levels found with the LFD. This suggests that while a HFD may stimulate the effect of BAT, long term exposure may have adverse effects on BAT activity. This may be due to internal factors that will need to be examined further.
ContributorsSion, Paul William (Author) / Herman, Richard (Thesis director) / Borges, Chad (Committee member) / School of Molecular Sciences (Contributor) / Barrett, The Honors College (Contributor)
Created2017-05
Description
The purpose of this study is to examine the effect of an existing medication management program in Hispanic individuals with diabetes, focusing on overall management and perceived quality of life (QOL). Diseases such as diabetes affect an individual's physical health, mental health, and social life. The degree to which these diseases affect an individual's life depend on how well they control and self-manage care needs. It has been found that Hispanic patients report and demonstrate inadequacy with controlling their diabetes compared to other ethnicities, making this an important public health topic (Schneiderman eta al., 2014). One of the greatest issues the Hispanic population reports as causing most concern is medication management and compliance. Poor medication adherence can increase complications of diabetes and depression, thus increasing poor overall health status and perception. Medication therapy management (MTM) programs run by clinical pharmacists are available to help with medication adherence, aiding in developing a tailored plan to help individuals manage the disease. This study is a cross-sectional study which assess reported QOL and functionality of diabetics enrolled in an MTM program. Participants were recruited from a clinic in Phoenix, Az. Patients completed a questionnaire that included demographics, a QOL questionnaire and a health belief questionnaire. A total of sixteen participants completed the study. The association between time in the medication therapy management program and its effect on general health, social functioning, emotional well-being, and hemoglobin A1C were reviewed. Though no significance was found, means were similar in all groups indicating functionality and A1C control through the diabetes support program may exist.
ContributorsVarela, Zury Arely (Author) / Flom-Racoma, Kehart (Thesis director) / Ohri-Vachaspati, Punam (Committee member) / Arizona State University. College of Nursing & Healthcare Innovation (Contributor) / Barrett, The Honors College (Contributor)
Created2016-05
Description
According to the CDC, diabetes is the 7th leading cause of death in the U.S. and rates are continuing to rise nationally and internationally. Chronically elevated blood glucose levels can lead to type 2 diabetes and other complications. Medications can be used to treat diabetes, but often have side effects. Lifestyle and diet modifications can be just as effective as medications in helping to improve glycemic control, and prevent diabetes or improve the condition in those who have it. Studies have demonstrated that consuming vinegar with carbohydrates can positively impact postprandial glycemia in diabetic and healthy individuals. Continuous vinegar intake with meals may even reduce fasting blood glucose levels. Since vinegar is a primary ingredient in mustard, the purpose of this study was to determine if mustard consumption with a carbohydrate-rich meal (bagel and fruit juice) had an effect on the postprandial blood glucose levels of subjects. The results showed that mustard improved glycemia by 17% when subjects consumed the meal with mustard as opposed to the control. A wide variety of vinegars exists. The defining ingredient in all vinegars is acetic acid, behind the improvement in glycemic response observed with vinegar ingestion. Vinegar-containing foods range from mustard, to vinaigrette dressings, to pickled foods. The benefits of vinegar ingestion with carbohydrates are dose-dependent, meaning that adding even small amounts to meals can help. Making a conscious effort to incorporate these foods into meals, in addition to an overall healthy lifestyle, could provide an additional tool for diabetics and nondiabetics alike to consume carbohydrates in a healthier manner.
ContributorsJimenez, Gabriela (Author) / Johnston, Carol (Thesis director) / Lespron, Christy (Committee member) / School of Nutrition and Health Promotion (Contributor) / School of International Letters and Cultures (Contributor) / Barrett, The Honors College (Contributor)
Created2016-05
Description
This project details the synthesis and analysis of five analogs of model compound NEt-4IB (6-[ethyl(4-isobutoxy-3-isopropylphenyl)amino]nicotinic acid), that target the retinoid-X-receptor (RXR). These molecules were synthesized by substituting, adding, or removing substituents in the nitrogen-containing ring of NEt-4IB. The parent compound is a RXR partial agonist and has proven to be effective in the treatment of type II diabetes without the unwanted side effects seen with full agonists. Many of the current drugs used to treat type II diabetes are accompanied by adverse effects including increased triglyceride levels, weight gain, and hypoglycemia. Biological evaluation with KK-Ay (obese diabetic) model mice indicates that NEt-4IB may even be more effective than current drugs on the market, like pioglitazone. As a result, it is predicted that due to such structural similarity, the analogs synthesized for this work will perform equally, if not better than, NEt-4IB.
ContributorsMaiorella, Emma Lauren (Author) / Wagner, Carl (Thesis director) / Marshall, Pamela (Committee member) / School of Mathematical and Natural Sciences (Contributor) / Barrett, The Honors College (Contributor)
Created2016-05
Description
Diabetes is prevalent among the Latino population in the United States. Engagement in healthy dietary behaviors, especially as a young adult, is an effective means of reducing risk for diabetes. Previous psychological theories have demonstrated that health beliefs and perceived barriers influence engagement in such behaviors. This research investigated beliefs regarding risk for diabetes among the young, educated Latino population. Study 1 of this research sought to compare health beliefs and perceived barriers to barrier change in the young, educated Latino and European American populations. Latinos reported to have a higher perceived vulnerability to diabetes, but shared the belief in diet as the most important determinant of diabetes risk with European Americans. However, Latinos saw their diet as less malleable in their lives than did European Americans. Study 2 sought to replicate these findings and verify the existence of these beliefs. Young, educated Latinos' beliefs in the importance of diet yet a perceived lack of dietary changeability were confirmed. Furthermore, Study 2 evaluated the efficacy of health messages based in the principle of social proof in motivating health behavior change. Social proof, or social validation, describes the phenomenon in which people who see others similar to them engaging in a particular behavior are more likely to engage in that behavior. Latinos who were randomly assigned to receive a health message utilizing the principle of social proof to motivate healthy dietary changes were more likely to express a willingness to change their diet than those who did not receive such a message. These findings can inform the development of health campaigns seeking to promote healthy behaviors among young, educated Latinos.
ContributorsTowers, Michelle (Author) / Kwan, Virginia S. Y. (Thesis director) / Aiken, Leona S. (Committee member) / Williams, Deborah L. (Committee member) / Basilio, Camille D. (Committee member) / Barrett, The Honors College (Contributor)
Created2014-05