Thesis (Ph. D.) -- University of Texas Southwestern Medical Center at Dallas, 2003. / Vita. Bibliography: 160-174.

Acanthamoeba are ubiquitous protists that play an environmental role in regulating microbial diversity; they also occasionally cause infections of the eye (Acanthamoeba keratitis) and brain (granulomatous amoebic encephalitis). These organisms exhibit two distinct phenotypes. The trophozoite form dominates in favorable conditions, in which the Acanthamoeba move through the extension of pseudopodia, engulfing microbes and other particles. During stressful conditions, the Acanthamoeba undergo a process of encystment, in which they build a double cell wall and become relatively inactive. The cyst form can survive years until more favorable conditions arise, at which point they may excyst. For this study, multiple laboratory encystment methods were compared to determine the percent encystment and the different viabilities of laboratory-produced cysts. Furthermore, four different encystment genes were targeted for development of a primer library for reverse-transcription, polymerase chain reaction expression studies. The library was developed using sequences accessed from various databases, including NCBI and EMBL; primers were screened through polymerase chain reaction, and those primers producing positive results were used to further screen cellular RNA that was extracted from encysting cells over various time points during the encystment process, and using various encystment media. Using these methods, target gene involvement in the encystment process was compared between species and encystment methods. These studies lay the foundation for quantitative gene expression analysis, and provide the basis for comparison of various encystment methods.

Thesis (Ph.D.) -- University of Texas Southwestern Medical Center at Dallas, 2006. / Embargoed. Vita. Bibliography: 117-136.

The aim of this work is to enhance the detection and classification pipelines of an artificial intelligence (AI)-based decision support system (DSS) for diagnosing acanthamoeba keratitis (AK), a vision-threatening disease. The images used are taken with the in vivo confocal microscopy (IVCM) technique, a complementary tool for clinical assessment of the cornea that requires manual human analysis to support diagnosis. The DSS facilitates automated image analysis and currently aids in diagnosing AK. However, the accuracy of AK detection needs improvements in order to use it in clinical practice. To address this challenge, we utilize image brightness processing through multiscale retinex (MSR), and develop a custom-built image processing pipeline with deep learning model and rule-based strategies. The proposed pipeline replaces two deep learning models in original DSS, resulting in an overall accuracy improvement of 10.23% on average. Additionally, our improved pipeline not only enhances the original system’s ability to aid AK diagnosis, but also provides a versatile set of functions that can be used to create pipelines for detecting similar keratitis diseases.

This thesis examines unicellular microorganism of the genus Acanthamoeba, as well as the disease it causes - acanthamoeba keratitis. It is an eye disease, which occurs mainly in people using contact lenses. Since acanthamoeba attacks visual apparatus, several parts of the thesis are dedicated to the anatomy of said apparatus, especially to the eye ball. The symptoms, diagnostics, treatment as well as prevention of the disease are included as well. The thesis furthemore mentions individual types of contact lenses, their proper hygiene and care and most of all, the danger, that comes with improper handling - acanthamoeba keratitis. A survey, that took place among elementary school and high school students, found out, that almost none of the elementary school students wear contact lenses, whereas contact lenses are worn by approximately 15% of students at high school. Among other issues, the survey concludes, that only a small part of elementary school students prefers contact lenses to glasses, though glasses are needed by a vast majority of them. At high school level, wearing contact lenses becomes more common, for aesthetics or other reasons. Ophtalmologist is regularly visited by 35 % of interviewed students. An analysis of six different natural science and biology textbooks for the 8th grade of...