Friday, June 21, 2013
Final Oral Examination
Chair: Dr. Mark M. Banaszak Holl
Friday, June 21, 2013, 12:00 PM
Earl Lewis Room (3rd floor), Rackham
Genetic Engineering is the manipulation of a cell’s genome to heal or provide new functions to the cell. One important therapeutic application of Genetic Engineering is Gene Therapy, in which nucleic acid residues (NAR) are used as a pharmaceutical agent to treat diseases. Because cells are inherently resistant to foreign NAR, vector systems must be used in order to selectively and efficiently transfer functional forms of NAR into the cell. Currently, the most efficient vector systems are viruses. However, safety concerns over their use in humans make virus-based strategies non-viable in the long term. Polymer-based vector systems, however, circumvent the safety issue and tend to be more practical in terms of customization and mass production. Despite these safety and manufacturing advantages, polymer-based vector systems are inefficient when compared to virus-based vector systems. Efforts to improve the polymer-based vector systems have assumed that cells play a passive role and don’t actively respond to polymer vector systems. However, I will show this assumption is incorrect. In my talk, I will show that cells respond to polymer systems by activating cytosolic nucleases and how this nuclease activity can be measured with the help of Molecular Beacon (MB). We see that nuclease activation as measured by MB has direct impact on gene expression facilitated by the polymer system used. In doing this, I show that it is possible to screen multiple polymer-based vector systems, thereby increasing the probability of identifying and designing a safe and efficient polymer vector system. The second half of my talk will concentrate on degradation characteristics of cytosolic nucleases. High-throughput sequencing was used to identify and quantify degradation pattern of these cytosolic nucleases on a plasmid. We will also see that S1 nuclease (a known nuclease) has a similar degradation pattern as cytosolic nucleases, supporting the hypothesis that nucleases like S1 nuclease are part of this cytosolic nuclease milieu. Designing polymer vector systems that protect these labile sites on DNA can improve gene expression.
Monday, June 24, 2013
Final Oral Examination
Madhu Sudhan Reddy Gudur
Chair: Dr. Cheri X. Deng
Monday, June 24, 2013, 10:30 AM
General Motors Conference Hall, 4th Floor Lurie Engineering Center (LEC)
Even though ultrasound imaging is widely used in clinical diagnosis and image-guided interventions, the field is far behind other areas of clinical image analysis, such as MRI, CT and X-ray mammography. In this thesis, non-destructive and non-invasive ultrasound characterization techniques were developed to study the tissue micro-structural details using high frequency spectral ultrasound imaging (SUSI). The techniques were explored in in-vitro conditions of acellular and cellular tissue engineered constructs and then on ex-vivo tissues for their characterization. SUSI was used to assess the amount of hydroxyl-apatite (HA) mineral, differentiate HA mineral types and study their distribution in acellular tissue engineered constructs. The process of mineral deposition from surrounding mineralizing media onto simple collagen constructs was also studied and characterized with SUSI. 3D morphological changes of the constructs with MC3t3 cells was monitored and characterized for the developmental changes such as net cell proliferation/apoptosis and cell differentiation process through mineral production by the early osteoblastic MC3t3-cell constructs in-situ. A novel method was introduced using SUSI to estimate the amount of mineral secreted by the differentiated osteoblast cells in a non-destructive method. Then, SUSI was investigated in ex-vivo cardiac tissues to monitor and characterize the cellular changes during high-intensity focused ultrasound ablation with high-frame-rate and high-resolution ultrasound imaging. The mechanistic hypotheses behind the improvement in lesion detection were investigated and best identification methods to assess lesion formation and transient gas body activities were proposed to provide a method for visualizing spatiotemporal evolution of lesion and gas–body activity and for predicting macroscopic cavity formation upon its implementation as a real-time monitoring technique with feedback control system for HIFU treatment of atrial fibrillation to improve the ablation process. Even though the results from the developed techniques show great promise in in-vitro and ex-vivo settings, additional work needs to be carried out to demonstrate the applicability of the techniques in in-vivo.