Browsing by Subject "Diagnosis"
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Item Admittance measurement for early detection of congestive heart failure(2010-05) Porterfield, John Edward; Pearce, John A., 1946-; Valvano, Jonathan W.; Yilmaz, Ali; Rylander, Henry G.; Feldman, Marc D.Impedance has been used as a tool for cardiac research since the early 1940’s. Recently there have been many advances in this field in the diagnosis of human heart failure through the measurement of pacemaker and ICD coupled impedance detection to determine the state of pulmonary edema in patients through drops in lung impedance. These new detection methods are far downstream of the initial changes in physiology, which signify heart failure risk, namely, an increased left ventricular (LV) end-diastolic volume (also known as preload). This dissertation presents the first formal validation of the complex admittance technique for more accurate blood volume measurement in vivo in mice. It aims to determine a new configuration of admittance measurement in a large scale animal model (pigs). It also aims to prove that “piggybacking” an admittance measurement system onto previously implanted AICD and bi-ventricular pacemakers is a feasible and practical measurement that will serve as an early warning system for impending heart failure through the measurement of LV preload, which appears before the currently measured drop in lung impedance using previous techniques.Item An electron microscopic, cytochemical study of the in vitro phagocytosis of latex particles by peritoneal phagocytes(Texas Tech University, 1971-08) Burk, Kenneth HNot availableItem An electron microsopic, cytochemical study of the effects of x-irradiation on mammalian testes(Texas Tech University, 1970-12) Vollet, John JNot availableItem Clinical, non-invasive in vivo diagnosis of skin cancer using multimodal Spectral Diagnosis(2013-12) Lim, Liang; Tunnell, James W.The goal of this thesis is to study the potential of optical spectroscopy as a clinical diagnostic tool for melanoma and nonmelanoma skin cancer. Skin cancer is the most common cancer in the United States. Like most cancers, early diagnosis and treatment improves patient prognosis for both melanoma and nonmelanoma skin cancer. However, current “gold standard” for diagnosis is invasive, costly and time-consuming. A diagnostic procedure consists of a clinical examination of the suspicious lesion, followed by biopsy and histopathology, with an additional turnaround time of approximately one week. There is a need for an accurate, objective, noninvasive, and faster method to aid physician in diagnosing cancerous lesions, increasing diagnosis accuracy while preventing unnecessary biopsies. We propose Spectral Diagnosis, a system capable of noninvasive in vivo spectroscopic examination of human skin. The research objectives are: (1) Probe pressure effects on in vivo spectroscopy measurements of human skin, (2) Clinical trial of Spectral Diagnosis, (3) Design, construction, and characterization of a confocal Raman microspectroscope. Spectral Diagnosis utilizes an optical fiber probe that transmits and collects optical spectra in contact with the suspected lesion. We identified short term and light probe pressure effects to be minimal on diagnostic parameters, and should not negatively influence diagnostic performance. We conducted a clinical trial at the University of Texas MD Anderson Cancer Center, and our results show that principal components from three spectroscopy modalities (diffuse reflectance spectroscopy, laser induced fluorescence spectroscopy, and Raman spectroscopy) provide excellent melanoma and nonmelanoma skin cancer diagnosis. We also constructed and characterized a Raman microspectroscope, with the goal of developing a physiological-based fitting model to better understand the analysis of in vivo Raman spectroscopy data from human skin tissue.Item Diagnostic accuracy in motor speech disorders: an application of signal detection theory(Texas Tech University, 2004-05) Whitaker, Melissa C.; Bogschutz, Renee J.; Schmitt, Mary B.; Aoyama, Kastura; Corwin, Melinda D.The results of this study indicated that participants accurately and reliably differentiated normal from abnormal speech samples. Thus, all groups proficiently identified disordered cases while limiting the number of misdiagnoses; however, some degree of task difficulty was noted and clinical biases were evident. For this research question, group trends indicated that the most experienced group of participants adopted a more lenient diagnostic criterion as compared to the intermediate and novice groups.Item Incident coronary atherosclerosis, unstable angina, non-ST-segment elevation myocardial infarction or ST-segment elevation myocardial infarction in type 2 diabetes : is mean glycated hemoglobin a good predictor?(2010-12) Owusu, Yaw Boahene; Lawson, Kenneth Allen, 1952-; Barner, Jamie C.; Jokerst, Jason R.; Lopez, DebraBackground: Glycated hemoglobin is the indicator of long-term diabetes control and a value below 7 percent is recommended by the American Diabetes Association (ADA) to reduce cardiovascular complications. Diabetic patients have a two- to four-fold risk of cardiovascular disease and approximately two-thirds of diabetic patients die as a result of cardiovascular complications. Three large prospective randomized controlled long-term trials within the last decade reported no significant reduction in cardiovascular complications in type 2 diabetic patients by intensive glycemic control. To the author's knowledge, no known retrospective studies have examined the association between mean serial glycated hemoglobin and coronary atherosclerosis (CA) or acute coronary syndromes (ACS). Objective: This study was designed to determine the association between mean serial glycated hemoglobin with incident CA or ACS in type 2 diabetic patients after controlling for age, gender, hypertension, low density lipoprotein cholesterol (LDL-C), microalbuminuria, aspirin use, statin use, insulin use, tobacco use, and body mass index (BMI). Methods: The study was a retrospective cohort database analysis using the Austin Travis County CommUnityCare[trademark] clinics' electronic medical record for the time period between October 1, 2004 and September 30, 2009. The primary outcome of the study was the incidence of CA or ACS and the primary independent variable was glycated hemoglobin (<7% vs. [greater than or equal to]7%). The study subjects included type 2 diabetic patients aged 30 to 80 years with at least one glycated hemoglobin value per year for a minimum of two consecutive years. Study subjects were excluded if CA or ACS occurred within six months of the index date (i.e., first glycated hemoglobin). Logistic regression analysis was used to address the study objective. Results: Overall, 3069 subjects met the study inclusion criteria with a mean follow-up period of approximately two years. Two percent (N=62) of the subjects had incident CA or ACS. After controlling for age, gender, hypertension diagnosis, LDL-C, microalbuminuria, aspirin use, statin use, insulin use, tobacco use and BMI, there was no significant association (OR=1.026, 95% CI=0.589-1.785, p=0.9289) between mean serial glycated hemoglobin and the incident diagnosis of CA or ACS. Increasing age (OR=1.051, 95% CI=1.025-1.077, p<0.0001), male gender (OR=1.855, 95% CI=1.105-3.115, p=0.0195) and normal weight (normal or underweight compared to obese: OR=0.122, 95% CI=0.017-0.895, p=0.0438) were significantly associated with incident CA or ACS. Conclusions: Mean serial glycated hemoglobin (comparing [greater than or equal to]7% to <7%) was not significantly associated with CA or ACS over a mean follow-up period of approximately two years. Until more evidence becomes available, clinicians and diabetic patients should target glycated hemoglobin level below or close to 7 percent as recommended by the ADA soon after diagnosis while concomitantly controlling nonglycemic risk factors of cardiovascular disease (statin use, aspirin use, blood pressure control, smoking cessation and life style modification), to reduce their long-term risk of incident CA or ACS.Item Inter-and intra-judge reliability in modified barium swallows(Texas Tech University, 1995-12) Davies, Jana DeniseThe assessment of dysphagia is often completed usmg videofluoroscopy (i.e., modified barium swaUow). This procedure has become a standard measure for evaluation, however, the procedure remains subjective and no accepted protocol for administration is agreed upon by professionals. No previous research has attempted to measure rehabihty of the professionals performing the modified barium swallow. Nineteen speech-language pathologists who manage dysphagia in their places of employment evaluated a set of 40 modified barium swallows (MBSs) and provided scores for features of oral, pharyngeal, and esophageal stages of swaUowkig for each. Subjects were required to evaluate the MBSs using a five-point scale. AdditionaUy, subjects were asked to provide a feedkig status and diet for each MBS. The data from each speech-language pathologist and MBS were compUed and analyzed for degrees of inter- and intra-judge rehability.Item Network mechanisms underlying susceptibility to helplessness and response to the antidepressant fluoxetine(2010-05) Padilla, Eimeira; González-Lima, Francisco, 1955-; Delville, Yvon; Domjan, Michael P.; Dominguez, Juan M.; Beevers, Christopher G.Depression and post-traumatic stress disorder are common psychiatric comorbidities related to stress. These conditions are frequently treated with antidepressants such as selective serotonin reuptake inhibitors (SSRI’s). However, there are individual differences in susceptibility to stress-induced psychopathologies and response to antidepressants. Therefore, there is a need to identify biologic factors that predict vulnerability to stress and response to treatment. Furthermore, few studies have examined the neural correlates of antidepressant treatment response in a stress-susceptible animal model. This dissertation had three specific aims: 1) to characterize behavioral predictors of stress vulnerability by studying three dimensions of temperament (reward dependence, novelty-specific activity and harm avoidance) before stress exposure using a stress-susceptible rat strain, 2) to identify the neural network effects of response and non-response to SSRI treatment using a stress-susceptible animal model, and 3) to determine the neurophysiologic correlates of helplessness susceptibility. This was examined via measurement of regional brain metabolic capacity and functional connectivity within relevant neural circuits, and measurements of corticosterone and heart rate. These effects were studied in rats that underwent inescapable shock exposure followed by escape testing. Holtzman rats showed greater predisposition to helpless behavior following inescapable shock compared to Sprague Dawley and Long-Evans strains. Also, increased activity in a novel environment and low heart rate appeared to be markers of helplessness susceptibility in Holtzman rats. Limbic-cortical network effects were identified that distinguished between responders and non-responders to antidepressant treatment in the Holtzman strain. Finally, hypermetabolism of the lateral habenula and a less interactive prefrontal-limbic cortex were identified in subjects with higher susceptibility towards helplessness within the Holtzman strain. Similar findings have been reported with other depression animal models and human neuroimaging studies. These findings support that the helpless dimension of mood disorders can be accurately modeled with the Holtzman rat strain and confirm that the lateral habenula and prefrontal cortex are key regions mediating the helpless phenotype and response to SSRI treatment.Item Precedent-free fault isolation in a diesel engine EGR valve system(2009-12) Cholette, Michael Edward; Djurdjanovic, Dragan; Fernandez, Benito R.An application of a recently introduced framework for isolating unprecedented faults for an automotive engine EGR valve system is presented. Using normal behavior data generated by a high fidelity engine simulation, the Growing Structure Multiple Model System (GSMMS) is used to construct models of normal behavior for EGR valve system and its various subsystems. Using the GSMMS models as a foundation, anomalous behavior of the entire system is then detected as statistically significant departures of the most recent modeling residuals from the modeling residuals during normal behavior. By reconnecting anomaly detectors to the constituent subsystems, the anomaly can be isolated without the need for prior training using faulty data. Furthermore, faults that were previously encountered (and modeled) are recognized using the same approach as the anomaly detectors.Item The impact of diagnosing on psychologists’ treatment of, attitude towards, and perception of their clients(2016-08) Gaies, Samantha Elizabeth; Rude, Stephanie Sandra; Sherry, Alissa R; Drum, David J; Walker, Lorraine O; Cohen, Barry HIn the current milieu of health care, diagnoses are often a requirement for receiving mental health services. More specifically, insurance companies require diagnoses for reimbursement, and oftentimes a certain threshold of mental illness needs to be met for the insurance company to approve the treatment. Additionally, newer models of health care, such as care management clinics, also prefer clients to be diagnosed to help indicate which evidence-based practice of care should be employed (Unützer et al., 2006). As a result, psychologists have become accustomed to offering more severe diagnoses than a client may warrant (Pomerantz & Segrist, 2006). Due to cognitive errors and biases that are inherent to cognitive processing, such as the negativity bias (Rozin & Royzman, 2001), labeling clients with pathologies may influence psychologists to hold less accurate and more negative views of their clients. In order to better understand the effects of using diagnoses, an experiment was conducted in which psychologists were either required or not required to assign a diagnosis to a hypothetical client based on written simulated therapy vignettes. It was hypothesized that participants required to diagnose would: 1) be more likely to diagnose that client at the end of the experiment; 2) have less of a desire to work with the client; and 3) hold more negative opinions of the client than psychologists who were not required to diagnose. Multiple regression models were run to test these hypotheses, and the results demonstrated that psychologists who were required to diagnose held a more negative opinion of the client, and the more often psychologists were diagnosing in their own practice, the more likely they were to diagnose the client in the study. Supplemental analyses also revealed that participants with Ph.Ds. from Clinical Psychology programs tended to be more likely to diagnose the hypothetical client and to use CBT techniques. All of these findings advance research and practice by demonstrating that the use of diagnoses has an effect on the therapeutic relationship, treatment, and the psychologist over time, and highlight the need for future research to explore the degree to which diagnosing may detrimentally affect client care.