Surgical revascularization by either natural or synthetic grafts, as well as less invasive percutaneous transluminal angioplasty (PTA), with or without stent implantation, is currently used in the treatment of vascular diseases. Despite its less invasive nature, stent implantation remains limited by in-stent restenosis within the stent struts. Although systemic administration of therapeutic drugs has shown disappointing results, the local delivery or presentation of therapeutic molecules/drugs/genetic material is a promising area for development. / The work that forms the basis of this thesis attempts to develop new devices or new strategies to achieve more efficient delivery of therapeutic biomacromolecules to the vascular walls during revascularization procedures. The work can be divided into three 3 Parts: (I) Modification of endovascular stents by hybrid coatings: two strategies involved the surface modification of the devices by plasma polymerization, followed by covalent immobilization of hyaluronan conjugated or able to be conjugated with a bioactive component (peptides/proteins or radionuclides). The last section of the Part I described the development of bioactive coating based on the Layer-by-Layer self-assembly of polysaccharide multilayers. (II) Development of a biodegradable membrane-covered stent: A chitosan-PEG blend has been used to engineer a biodegradable membrane-covered device for endovascular procedures. This membrane-covered device was able to sustain physiologic pressure, showed very small water permeability, displayed an appropriate haemocompatibility and could be used for drug delivery. (III) Development of nanocoatings to be self-assembled in situ onto the vascular wall: self-assembled multilayers have been investigated to protect damaged arteries and to control the healing processes by efficiently delivering therapeutic biomolecules to the vascular wall. These nanometric coatings have been deposited onto blood vessel by the Layer-by-Layer technique and have shown great potential for drug delivery of various macromolecules such as NO-donor or plasmid DNA.

The introduction of a single inhaler comprising a beta2-agonist and ipratropiurn (CombiventRTM) in the treatment of Chronic Obstructive Pulmonary Disease (COPD) should enhance compliance, improve patient outcomes and result in lower medication costs. / Using the Saskatchewan Health databases, a cohort of subjects initiating treatment with CombiventRTM was identified and followed up to one year. A reference cohort was formed from all subjects who were dispensed, for the first time, two canisters, one of ipratropium and one of inhaled beta 2-agonist, on the same day. / CombiventRTM users presented lower costs associated with inhaled bronchodilators (RR = 0.83; 95% Cl: 0.76 -- 0.92), despite a slight increase in overall use of these medications (RR = 1.16; 95% Cl: 1.07 -- 1.26). Moreover, the use of other respiratory drugs and antibiotics was unchanged (RR = 1.03; 95% Cl: 0.93 -- 1.16). / The availability of a simpler dosing regimen did not alter significantly the treatment of COPD and resulted in appreciable cost savings.

The purpose of this study was to determine whether pancreatic ductal epithelium has trophic effects on the islets of Langerhans, and how this intercellular communication might be mediated. Islets and ducts were isolated from hamster pancreata. Islets were purified on a bovine serum albumin gradient. Primary duct cultures were passaged twice for cell purification. Duct-conditioned medium (DCM) was collected from duct cultures passaged twice. The islets were allocated to three experimental groups: (1) 100 islets alone; (2) 100 islets + 80 tertiary ducts and (3) 100 islets in 25% DCM. All tissues were embedded in rat tail collagen for the duration of the study. The influence of pancreatic ductal epithelium on islet cell death (necrosis and apoptosis), islet morphology, and islet-cell proliferation was examined. As determined by inverted microscopy, 17.3% $ pm$ 1.8 of the islets cultured alone, demonstrated central necrosis, in comparison to 4.6% $ pm$ 1.0 of the islets co-cultured with ducts (p $<$ 0.05). Specific cell death detection ELISA indicated that DNA fragmentation in islets cultured alone (0.23 $ pm$ 0.04), was significantly increased compared to islets cultured with ductal epithelium (0.09 $ pm$ 0.02) (p = 0.03). At 27$ sp circ$C, 60.5% $ pm$ 8.8 of the islets cultured alone showed peripheral cell disintegration, in contrast only 2.6% $ pm$ 0.3 (p $<$ 0.001) of the islets cultured with ducts. Tritiated thymidine incorporation into islets cultured with ducts (235.8 $ pm$ 33.9) was 120% higher than that in islets cultured alone (96.3 $ pm$ 18.8) (p = 0.01). Similar results were obtain from the third experimental group, when ductal epithelium was substituted with DCM. In conclusion, pancreatic ductal epithelium can stimulate islet cell survival and growth. This effect appears to be mediated in a paracrine manner by the release of factor(s) from the ductal cells into the media.

In the adult male rat, growth hormone (GH) is secreted in an ultradian fashion at regular 3.3-h intervals from the anterior pituitary. Physiological and morphological evidence indicates that this pattern of secretion may be the result not only of an interaction of the stimulatory hormone, growth hormone releasing factor (GRF) and inhibitory hormone, somatostatin (SRIF), at the level of the pituitary, but also at the level of the hypothalamus. Consistent with this, SRIF binding sites have been demonstrated on a subpopulation of GRF-containing neurons in the arcuate nucleus. The aim of this study, in general, was to examine what role, if any, these bindings sites play in the temporal regulation of GH secretion at the level of the hypothalamus. More specifically, the possibility of the existence of a temporal relationship between the established ultradian oscillation of GH secretion from the anterior pituitary and postulated fluctuation in the number and/or density of SRIF binding sites in the arcuate nucleus was examined. (Abstract shortened by UMI.)

An on-line beam to target portal verification technique has been developed for stereotactic radiosurgery. Conventional radiosurgery employs a stereotactic frame in order to obtain sufficient spatial accuracy in dose delivery. Frame based verification methods attempt to ensure accurate target positioning with respect to the frame but they do not account for possible movement of the frame with respect to the anatomy and isocenter. We account for this possibility by superimposing digitally reconstructed radiographs (DRRs) over orthogonal edge detected digital portal image pairs. By developing a process for interactively manipulating the CT-data in three dimensions (rotations and translations) new DRRs are generated and overlaid with orthogonal portal images. This method is able to account for ambiguities in matching due to rotations and translations outside the imaging plane because of the availability of DRRs at any possible orientation. This matching procedure is performed using only the anatomy and is used in tandem with a fiducial marker array attached to the stereotactic frame. The method is evaluated using portal images simulated from patient CT-data and then tested using a radiographic head phantom. Results show that repositioning precision of the system is at the level required by stereotactic radiosurgery.

The etiology of obesity involves imbalanced energy intake and utilization. ASP is an adipose tissue hormone that facilitates adipocyte uptake of serum fatty acids and their storage. Mice lacking ASP have less adipose tissue mass, despite increased food intake, than wild-type littermates. We hypothesize that the unstored fuels are oxidized through UCP (thermogenic mitochondrial carriers). / In male ASP-deficient mice mRNA levels were measured by semi-quantitative RT-PCR and the following changes were observed: UCP-1 decreased in all tested tissues, UCP-2 increased by 15% and 6 fold in muscle and white adipose tissue and UCP-3 increased 2.5 and 10 fold in muscle and epididymal adipose tissue, respectively. In female ASP-deficient mice UCP-1 decreased in all tissues, UCP-2 increased by 10% and 40% in inguinal and brown adipose tissue, respectively, and UCP-3 remained stable in all tissues. High fat diet nullified these differences, and decreased all wild-type UCP levels. / We propose that UCP-2 and 3 assume the role of UCP-1 in fuel utilization, thus helping mice face an increased energy load in the absence of ASP.

Introduction. The use of Functional Magnetic Resonance Imaging (fMRI) in studying central auditory pathways expanded our knowledge of the neurophysiology of hearing. In various studies, an array of diverse auditory stimuli has been used, including pure tones and words, in a "Block" design. Few studies, thus far, have been performed using an event-related design. None of these has used pure tone stimulation. / Subjects and methods. In eight out of 13 subjects enrolled and scanned in this project, data have been acquired and processed. Binaural pure tone stimulation at 2kHz and one higher frequency at 6, 8, or 12 kHz, at 90 dB SPL was presented to all subjects, using a stroboscopic design in an attempt to eliminate cortical response to scanning noise. In addition, an unusually long time of repetition (TR) interval of 10 seconds was utilized. The aim in data processing was to generate: (a) a Peak Height Map (PHM) with selection of areas of stimulation based on the maximal response; (b) a statistical map from the raw data of the images. / Results. No consistent morphology was detected in the BOLD event-related curves, corresponding to the percentage change from baseline over time. Such curves revealed significant oscillation with marked dips below baseline, highly suggestive of an irregular noise pattern. Comparing the curves to each other, no discernible shape or similarities were noted. / Conclusion. Attempting to extract both the temporal and spatial characteristics of the cortical response to pure tone stimuli resulted in a dispersal of data over many parameters, therefore "diluting" it. This, in turn, yielded a negative result where the responses were "drowned" revealing but a noise pattern.

Cellular cardiomyoplasty (cell therapy for myocardial regeneration) targets the basic pathophysiology of heart failure and represents a novel means of augmenting cardiomyocyte number and contractile function of the failing heart. / Chapter I reviews briefly current approaches to the treatment of heart failure. Cellular cardiomyoplasty is introduced and previous work conducted in our laboratory is reviewed. Chapter II focuses on the possibility of using marrow stromal cells as a cell source for cellular cardiomyoplasty. This proof-of-principle study was conducted in association with Dr. Jih-Shiuan Wang. The results are convincing that marrow stromal cells can differentiate into myocardial-like cells. / For implanted cells to contribute to myocardial function they must be integrated with the host myocardium. Chapter III focuses on this topic. Using satellite cells and stromal cells, morphological and histochemical analyses show that implanted cells do, in fact, incorporate into the host myocardial structure. Chapter IV includes closing remarks.

These investigations examined the relative function of costal and crural diaphragm segments. This work produced the first direct measurements of length and electromyogram (EMG) of the diaphragm in an awake, intact animal. / Examination of diaphragm function following laparotomy revealed a consistent pattern of postoperative segmental recovery, and showed the inadequacy of EMG alone as an indicator of diaphragm activity. Segmental contraction during airway occlusion was confirmed to be non-isometric and different per segment. The basic relation between segmental velocity of shortening and mean inspiratory flow, was confirmed for diaphragm but not for intercostal musculature. Anesthesia produced a distinctive alteration in the resting length of crural compared to costal segment, suggesting a difference in inherent segmental tonic activity. Costal and crural activity during hypoxic and hypercapnic stimulated breathing revealed different, stimulant-specific activities of the segments; hypoxia elicited prominent crural post inspiratory activity (PIIA). During thermal panting, peak crural shortening was out of phase with costal shortening and inspiratory airflow. This unique segmental asynchrony may represent a natural analog to high frequency ventilation. / We conclude that costal and crural diaphragm segments can function as individual segment-muscles, exhibiting distinctive, differential activities under certain conditions of respiration.

The aim of the present investigation was to study the structural variability of osteoarthritic human femoral condylar cartilage proteoglycans that can aggregate with hyaluronic acid as compared with site and age matched normal adult cartilage proteoglycans. Using specific antibodies to different parts of the proteoglycan molecule in radioimmunoassays, we were able to detect four proteoglycan populations of different hydrodynamic sizes in normal, as well as in osteoarthritic articular cartilage. These populations were: a large chondroitin 6-sulfate, a smaller chondroitin 4-sulfate, and an even smaller keratan sulfate population together with the hyaluronic acid-binding region. Osteoarthritic articular cartilage contained increased amounts of a foetal-specific epitope, 846, and a decrease in the characteristic adult cartilage proteoglycans. As determined histologically, using a grading system for cartilage degeneration, early in the disease (phase I), the proteoglycans appear to be smaller in size than in normal adult cartilage, while in the later stages of the disease (phase II) they appear to be larger in their hydrodynamic size. The hyaluronic acid-binding region appeared to be functional and proteoglycan aggregation with hyaluronic acid was not altered in osteoarthritis. The data indicate an attempt by the osteoarthritic cartilage at remodeling and repair by making an immature type of proteoglycan.