Browsing by Subject "Diagnosis"

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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.
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.
Improving test compression and diagnosis for system-on-chip designs
(2016-12) Saleem, Kamran, Ph. D.; Touba, Nur A.; Pan, Zhigang; Orshansky, Michael; Gharpurey, Ranjit; Suleman, Muhammad A
This dissertation presents new approaches to improve test compression and fault diagnosis for system-on-chip (SOC) designs. SOCs typically contain one or more embedded processors which can be used to aid in test and diagnosis. Novel techniques are presented for test vector compression and output response compaction running in software on an embedded processor, and for diagnosis from compactor signatures. The proposed test compression technique is based on a novel algorithm called Recursively Defined Invertible Sets (RDIS). It exploits the abundance of don’t cares in industrial test data and achieves large amounts of compression. The compressed data is stored on the tester and transferred on-chip to be decompressed by the software program. A test response compaction technique is proposed and implemented in software. Unlike previous techniques for software based test response compaction, the proposed approach is able to handle output responses with unknown (X) values. The methodology is based on canceling out X's in response signatures while using cost-effective X masking as a preprocessing step. The results indicate significant improvement in compression compared with previous approaches. A fundamentally new technique for precisely identifying error locations from output response signatures for propagation cones reaching fewer scan cells than the size of the MISR is described. The proposed approach does not require any additional hardware or extra data to be collected. It uses off-line software-based processing to extract information from signatures to deduce error locations even when there are a large number of errors. Experimental results demonstrate the reductions in suspect set size that can be obtained with the proposed techniques. The above diagnosis technique is further improved by a novel circuit partitioning technique that adds observation points to observe faults before they can spread out to too many primary outputs. An extra MISR is introduced to compact the data form these observation points. By careful selection of the location of the observation points, the maximal propagation cone for any fault to one of the MISRs is kept small enough to allow precise diagnosis of the error locations. All the aforementioned methods are described in detail along with experimental results.
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, Debra
Background: 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.
Individual metabolic patterns and human disease : an exploratory study utilizing predominantly paper chromatographic methods
(University of Texas, 1951-05-01) University of Texas
Table of Contents. Introduction, general discussion and tentative conclusions / by Roger J. Williams (p. [7]-21) -- Development of paper chromatography for use in the study of metabolic patterns / by Helen Kirby Berry ... [et al.] (p. [22]-55) -- The influence of solvent composition, temperature and some other factors on the Rf values of amino acids in paper chromatography / by B. Jirgensons (p. [56]-70) -- Quantitative study of urinary and salivary amino acids using paper chromatography / by Helen Kirby Berry and Louise Cain (p. [71]-76) -- The quantitative determination of histidine using paper chromatography / by Louise Cain and Helen Kirby Berry (p. [77]-79) -- The quantitative determination of creatinine in urine using paper chromatography / by Helen Kirby Berry and Louise Cain (p. [80]-81) -- The quantitative determination of creatine in urine using paper chromatography / by Louise Cain (p. [82]-83) -- The quantitative estimation of uric acid by paper chromatographic methods, with applications to human urine and saliva / by Helen Kirby Berry (p. [84]-87) -- The quantitative estimation of urea by paper chromatographic methods with application to human urine / by Helen Kirby Berry (p. [88]-92) -- A micro determination of sodium using paper chromatography / by Harry Eldon Sutton (p. [93]-96) -- Quantitative study of ketosteroids by paper chromatographic methods with applications to human urine / by Eric Bloch, Ernest Beerstecher, Jr., and Roy C. Thompson (p. [97]-108) -- The determination of ferric chloride chromogens in human urine by paper chromatographic methods / by Harry Eldon Sutton and Ernest Beerstecher, Jr. (p. [109]-114) -- The effects of single vitamin deficiencies on the consumption of alcohol by white rats / by Ernest Beerstecher, Jr. ... [et al.] (p. [115]-138) -- Individual excretion patterns in laboratory rats / by Janet G. Reed (p. [139]-143) -- A study of the alcoholic consumption and amino acid excretion patterns of rats of different inbred strains / by Janet G. Reed (p. [144]-149) -- A study of the urinary excretion patterns of six human individuals / by Helen Kirby Berry, Louise Cain, and Lorene Lane Rogers (p. [150]-156) -- Further studies on individual urinary and salivary amino acid patterns / by Helen Kirby Berry (p. [157]-164) -- Individual urinary excretion patterns of young children / by Helen Kirby Berry and Louise Cain (p. [165]-172) -- A further study of urinary excretion patterns in relation to diet / by Harry Eldon Sutton (p. [173]-180) -- Metabolic patterns of underweight and overweight individuals / by Jack D. Brown and Ernest Beerstecher, Jr. (p. [181]-188) -- Metabolic patterns of schizophrenic and control groups / by M. Kendall Young, Jr. ... [et al.] (p. [189]-197) -- Exploration of metabolic patterns in mentally deficient children / by Louise Cain (p. [198]-205).
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.
Novel routes for cytomegalovirus diagnosis and treatment
(2017-05) Hilterbrand, Adam Thomas; Upton, Jason W.; Croyle, Maria A; Ehrlich, Lauren I; Huibregtse, Jon M; Sullivan, Christopher S
Human cytomegalovirus (HCMV) represents a massive burden on infected individuals and healthcare systems worldwide. Though HCMV is not normally disease causing in healthy individuals, it poses a significant threat to immunocompromised people and developing fetuses, causing a broad range of diseases due to its ability to infect several organ and tissue types. Current diagnostic and treatment modalities for HCMV are extremely limited in their scope. In the United States, HCMV testing is typically only done when one presents with possible HCMV-caused symptoms, as current methods are deemed unwarranted if no symptoms are presented in a patient. Additionally, if treatment is to be given, current antiviral drugs are limited to targeting only one aspect of HCMV’s replication cycle and, at times, can be rather toxic. As such, continued research and development is needed to create rapid, facile point–of-care diagnostics as well as identify new druggable targets to lessen the impact of infection. Utilizing a murine model system to study HCMV infection, we recently showed that precise detection of murine cytomegalovirus (MCMV) from the urine of infected mice was rapidly achieved through the use of a novel electrochemical immunoassay. By attaching glucose oxidase to an antibody recognizing MCMV, we readily detected MCMV at an electrode using chemistry similar to that used in modern day glucometers. Additionally, we characterized and identified a major role for a uniquely structured MCMV deubiquitinating enzyme (DUB) during infection. When the virus lacked DUB activity, levels of a virally encoded pro-inflammatory chemokine increased, leading to the mutant DUB virus’ dramatic attenuation in mice. As this enzyme is incredibly important for MCMV pathogenesis and is highly conserved between MCMV and HCMV, it may serve as a viable target for antiviral therapies. Because HCMV infections persist for the lifetime of the individual, continued success in diagnosis and treatment of HCMV will be needed as long as humans exist as a species.
Paper-based electrochemical platforms for separation, enrichment, and detection
(2017-05) Li, Xiang, Ph. D.; Crooks, Richard M. (Richard McConnell); Stevenson, Keith J.; Shear, Jason B.; Mullins, Charles B.; Werth, Charles J.
Paper based analytical devices (PADs) have great potential in the application of point-of-care diagnosis. This dissertation focuses on the design and application of PADs, especially ones that integrate with electrochemical systems, to tackle various problems in analytical chemistry, such as multi-analyte separation, sample enrichment, and sensitive detection. Four types of PADs are described in this dissertation. The first PAD (oPAD-Ep) is designed for multi-analyte separation. The oPAD-Ep is fabricated using the principle of origami to create a stack of connected paper layers as an electrophoresis channel. Due to the thinness of paper, a high electric field can be achieved with low voltage supply. Serum proteins can be separated and the device can be unfolded for post-analysis. The second PAD (oPAD-ITP) is designed on a similar principle as the oPAD-Ep, but it is applied for sample enrichment. The major modification is to adjust electrolyte conditions to enable isotachophoretic enrichment of analytes. DNA with various lengths can be enriched within a few minutes, and can be collected on one of the paper folds. The third PAD (hyPAD) also focuses on sample enrichment. The device is assembled with two different paper materials, nitrocellulose and cellulose. The hyPAD can perform faradaic ion concentration polarization experiments. This technique uses faradaic electrochemistry to create a local electric field gradient in the paper channel and can enrich charged analytes including: DNA, proteins, and nanoparticles. The fourth PAD (oSlip-DNA) focuses on sensitive electrochemical detection of DNA hybridization assays. This method integrates magnetic enrichment and electrochemical signal amplification via silver nanoparticles. Using voltammetry, sensitive detection of Hepatitis B Virus DNA is achieved on the low-cost device.
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.
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 H
In 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.