<p> Influenza A virus (IAV) infection stimulates host anti-viral immune responses. This includes induction of innate anti-viral responses&mdash;which work early during infection to limit viral replication and spread&mdash;as well as long-lasting, antigen-specific, adaptive immune responses. The generation of adaptive B and T cells in response to IAV infection is well understood, and these are required for the clearance of IAV infection. This thesis addresses two major questions about the immunity induced by IAV infection. First, are there unexplored mechanisms of immunity elicited by IAV infection beyond the well-characterized B and T cell responses? And second, can we utilize our understanding of the relationship between IAV and the immune system to intentionally drive anti-tumor responses in the context of cancer? </p><p> To the first question, it has been observed that, following IAV infection, the host is protected from subsequent <i>unrelated</i> respiratory virus infections for a period of time. This observation runs contrary to our understanding of classical adaptive immune responses: this temporary nonspecific protection is neither explained by cross-reactive adaptive responses, nor prolonged interferon signaling. However, we have discovered a population of respiratory club cells (formerly known as Clara cells) that survive direct infection with IAV. Survival of IAV infection results in the &ldquo;reprogramming&rdquo; of these cells to an anti-viral response phenotype. Moreover, depletion of these cells abrogates the temporary non-specific immunity elicited following IAV infection, thus demonstrating the importance of cells surviving influenza virus infection as a mechanism for preventing viral diseases. </p><p> Additionally, IAV has been studied as an oncolytic agent because of its capacity to lyse tumor cells. We reasoned that intra-tumoral injection of IAV would directly lyse tumor cells as well as promote an anti-tumor adaptive immune response. To further promote an anti-tumor response, we engineered an IAV to express an antibody that inhibits the immune checkpoint CTLA4, (IAV-CTLA4). In the B16 mouse melanoma model, we found that IAV-CTLA4 potently delays tumor growth compared to mice administered unmodified IAV or vehicle control. Moreover, IAV-CTLA4 promotes a modest abscopal effect by delaying the growth of anatomically distant, untreated tumors, as well as enhancing overall survival. </p><p> Together, this thesis demonstrates that it is possible for IAV infection to promote desirable immune responses: either non-specific anti-viral protection or systemic anti- tumor effects. Findings discussed herein may inform future vaccine designs&mdash;where eliciting nonspecific immunity would be beneficial&mdash;or novel oncolytic viral therapies.</p><p>

There is general agreement that the extent of the risk from x-ray examination is related in some way to the radiation dose. As the dose increases, the likelihood of significant biological effects also increases. If a clear correlation between dose and effect is to be established, a convenient and reasonably accurate method of estimating patient’s absorbed doses during common radiographic examinations will be highly needed. A simple method is developed in this project to determine the two important parameters e exposure at skin entrance (ESE) and half value layer (IIVL), which is essential to get reasonably accurate estimates of absorbed doses. Then, the patient’s absorbed doses in common x-ray examinations can be estimated using the computer program. The absorbed doses in 12 routine radiographic projections were calculated by the use of clinical data in MCV Hospital.

Platelet mediated thrombosis has been a major source of mortality and morbidity in cardiovascular device patients as the device surface upon contact with blood induces surface thrombosis. Two specific objectives of this thesis are: 1) Identify the effect of phospholipid modification on Quatromer and 2) Identify the most effective modification technique that will inhibit the surface induced thrombosis and enhance the long-term blood compatibility of Quatromer. Six different phospholipids were grafted in the Quatromer and the role of each of the modified substrates was evaluated in terms of mechanical properties and hemocompatibility. The surface analysis studies showed a significant decrease in contact angle while an increase in the surface energy and the O/C ratio with phospholipid modification, indicating a highly hydrophilic surface with increased carbonyl groups on the surface contributing to lower platelet adhesion and activation. The comparative platelet adhesion tests showed significant decrease in platelet adhesion with phospholipid modification. Hence, phospholipid modification proves to be promising in increasing the long-term blood compatibility of Quatromer.

The microvasculature plays a significant role in the regulation of blood pressure and regional blood supply. Cardiotonic steroids like the adrenal cortical hormone (ouabain) have been proposed to play a role in some forms of hypertension. The purpose of this study was to determine the effect of different agonists on arteriolar diameter in the presence and absence of ouabain. In Vitro studies on isolated intact rat mesenteric arterioles were performed by administering different concentrations of the vasoconstrictor norepinephrine (NE) and the vasorelaxant acetylcholine (Ach) in the presence and absence of ouabain. NE induced constriction was not significantly enhanced in the presence of ouabain. Ach completely reversed NE-induced constriction without ouabain, which was significantly impaired in ouabain presence (p+Channel blockade almost completely abolished Ach-induced relaxation in presence and absence of ouabain.

A rapid detection and neutralization method for biowarfare agents would be a great biodefense in war times. With this purpose, liposomes were developed following the lipid film formation, rehydration, and extrusion procedure as the production method. MgOCl2 was encapsulated in the liposomes and it was tested with three different bacterium B. cereus; B. thuringiensis; and B. subtilis. For specificity, the liposomes were modified with a polyclonal antibody against B. cereus and B. subtilis. The liposomes were characterized using a Malvern Zetasizer Instrument, and the study revealed stability of the liposomes stored at 4°C for a period of 15 days. A live/dead assay revealed a significant reduction of bacterium incubated with MgOCl2-liposomes. Smaller reduction percentages, but yet significant, were observed with the MgOCl2-immunoliposomes. A colony growth assay revealed a significant reduction percentage for empty liposomes, MgOCl2-liposomes, and MgOCl2-immunoliposomes incubated with B. thuringiensis.

Characterizing engineered human lung tissue is an important step in developing a functional tissue replacement for lung tissue repair and in vitro analysis. Small tissue constructs were grown by seeding IMR-90 fetal lung fibroblasts and adult microvascular endothelial cells onto a Polyglycolic acid (PGA) polymer template. Introducing the constructs to dynamic culture conditions inside a bioreactor facilitated three-dimensional growth seen in scanning electron microscopy images (SEM). Characterization of the resultant tissue samples was done using SEM imagery, tensile tests, and biochemical assays to quantify extra-cellular matrix (ECM) composition. Tensile tests of the engineered samples indicated an increase in the mechanical properties when compared with blank constructs. Elastin and collagen content was found to average 3.19% and 15.49% respectively in relation to total mass of the tissue samples. The presence of elastin and collagen within the constructs most likely explains the mechanical differences that we noted. These findings suggest that the necessary ECM can be established in engineered tissue constructs and that optimization of this procedure has the capacity to generate the load bearing elements required for construction of a functional lung tissue equivalent.

Bacteria biohazards, such as Anthrax, are responsible for causing mild to serious illnesses in humans and animals. The primary aim of this research study was to develop a rapid one step assay to detect and neutralize bacteria-based biohazards, using an Immunoliposome-nanoparticle complex. An Anthrax model, Bacillus cereus, was grown for 3 hours and diluted 1:25 in media (2.0 x 107 cfu/ml). The Bacillus cereus was interacted with an Immunoliposome-nanoparticle complex containing an MgO-C 2 neutralization agent. The samples were analyzed via flow cytometry with a 1:8:1 ratio Bacillus cereus, Immunoliposome-nanoparticle complex, and Ethidium homodimer-1 for two hours. The results obtained showed when the Immunoliposome-nanoparticle complex were interacted with bacteria both detection and neutralization occurred immediately. As incubation time increased, fluorescence shifted closer to the control region. Therefore, bacteria can be immediately detected with the Immunoliposomenanoparticles complex, and high levels of neutralization can be achieved less than two hours of incubation.

The pathology of stroke attacks the central nervous system commonly resulting in the loss of voluntary neuromuscular control which negatively affects the walking capability of many survivors. New rehabilitation techniques utilizing biofeedback, robotic assisted movements, and gait specific exercises have been shown individually to increase the neurological recovery as compared to traditional methods of physical rehabilitation. The Biofeedback Assisted Robotic Ankle-foot orthosis (B.A.R.A.) is a prototype that combines all three characteristic treatments into a single portable device focused on improving voluntary dorsiflexion capability and gait patterns of the ankle-foot complex. The initial pilot study utilized a single healthy individual to study the joint angle patterns of the ankle while utilizing the BARA device in a drop-foot gait simulation. The resulting angular positional curves showed general patterns representative of a normal gait cycle while eliminating the hazardous effects of drop-foot.

The aim of this study was to develop a practical, versatile and fast dosimetry and radiobiological model for calculation of the 3D dose distribution and radiobiological effectiveness of radioactive stents. The algorithm was written in Matlab 6.5 programming language and is based on the dose point kernel convolution. The dosimetry and radiobiological model was applied for evaluation of the 3D dose distribution of 32P, 90Y, 188Re and 177Lu stents. Of the four, 32P delivers the highest dose, while 90Y, 188Re and 177Lu require high levels of activity to deliver a significant therapeutic dose in the range of 15-30 Gy. Results of the radiobiological model demonstrated that the same physical dose delivered by different radioisotopes produces significantly different radiobiological effects. This type of theoretical dose calculation can be useful in the development of new stent designs, the planning of animal studies and clinical trials, and clinical decisions involving individualized treatment plans.

By using near infrared spectroscopy (NIRS) and by modifying the current Somanetics® optodes being used with the INVOS oximeter, the modified optodes are made to be fairly functional not only across the forehead, but across the hairy regions of the scalp as well. A major problem arises in the positioning of these optodes on the patients scalp and holding them in place while recording data. Another problem arises in the inconsistent repeatability of the trends displayed in the recorded data. A method was developed to facilitate the easy placement of these optodes on the patients scalp keeping in mind thepatient's comfort. The sensitivity of the optodes, too, was improved by incorporating better refined techniques for manufacturing the fiber optic brushes and fixing the same to the optode transmitting and receiving windows. The modified and improved optodes, in the single as well as in the multiplexed modes, were subjected to various tests on different areas of the brain to determine their efficiency and functionality.