Theses and Dissertations at Montana State University (MSU)
Permanent URI for this collectionhttps://scholarworks.montana.edu/handle/1/733
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Item Does bone-to-cartilage fluid transport exist and is it relevant to joint health?(Montana State University - Bozeman, College of Engineering, 2024) Hislop, Brady David; Chairperson, Graduate Committee: Ronald K. June II; This is a manuscript style paper that includes co-authored chapters.Osteoarthritis (OA) afflicts millions of people each year. The onset of OA has been associated with many factors including increased bone-cartilage fluid transport, yet a cure remains elusive. To implicate bone-cartilage fluid transport in the progression of OA, further studies are needed on fluid transport in health. Recent studies have challenged the assumption that no fluid transport occurs between bone and cartilage in healthy joints. However, many gaps remain in our understanding of bone-to-cartilage fluid transport, including 1) do fluid pressure gradients develop at the bone-cartilage interface, 2) do traumatic injuries impact subchondral bone stiffness, and synovial fluid metabolism 3) do larger molecules move from bone-to-cartilage and does cyclic loading enhance such movement, 4) what material properties influence bone-to-cartilage fluid transport 5) do distinct metabolism changes occur with osteoarthritis, evaluated using a novel clustering method. Our results showed the development of fluid pressure gradients at the osteochondral interface, and that cyclic compression enhances bone-cartilage fluid transport. Furthermore, our results showed that proteoglycan loss, and decreased subchondral bone stiffness increased bone-cartilage fluid transport. Finally, we showed that in the first week after traumatic joint injuries (e.g., ACL tears) subchondral bone volume decreases, and subchondral bone stiffness increases, while the synovial fluid metabolism shifts. In conclusion, we showed that osteochondral fluid transport is enhanced by cyclic compression for larger molecules than previously studied (3kDa dextran), and that material parameters changes associated with the progression of OA alter bone-cartilage fluid transport. These studies provide novel understanding of bone-to-cartilage fluid transport, leading us one step closer to understanding OA as a whole joint disease.Item Clodronate use in yearling, exercising horses on endocrine regulation of bone growth and development(Montana State University - Bozeman, College of Agriculture, 2023) Conrad, Matthew Benjamin; Chairperson, Graduate Committee: Amanda N. BradberyExtra-label bisphosphonate use in juvenile horses is widespread despite limited scientific understanding of biological and welfare impacts on skeletally immature, exercising horses. The objective of this study was to determine the effects of clodronate on endocrine regulation of bone growth, hypothesizing there would be no effect. To test this, 32 Quarter Horses were stratified by age (500 + or - 13 d of age), BW (336 + or - 26 kg), sex (n = 16 males, n = 16 females), and initial bone optical density by aluminum equivalence into four treatment groups for a 168-d trial. The experimental period was divided into two phases mimicking sales preparation (Phase I: d 0-83) and early performance training (Phase II: d 84-168). Investigators were blinded, and all horses received iso-volumetric intramuscular injections of either 1.8 mg/kg BW clodronate disodium (OSPHOS®) or saline (placebo) on d 0, 42, 84, and 126. Treatments consisted of control (CON; n = 8), single-dose (1X; n = 8; d 84), two-dose (2X; n = 8; d 0, 84), and four-dose groups (4X; n = 8; d 0, 42, 84, 126). Physical measurements including BW, wither height (WH), hip height (HH), body length (BL), and heart girth (HG) circumference were recorded every 42 d from d 0. Serum samples were collected every 42 d prior to treatment administration to quantify growth hormone (GH), calcitonin (CT), parathyroid hormone (PTH), and ionized calcium. Data were analyzed using PROC MIXED of SAS. All physical growth parameters increased (P < or = 0.01) and growth hormone tended to decrease over time (P = 0.09) following normal growth patterns. A treatment time interaction was observed for PTH (P = 0.05) where concentrations increased on d 84 in 4X and on d 126 in 2x following the second administration of clodronate while 1X and CON remained unchanged. Ionized Ca decreased over time (P < 0.01) with no effect on CT concentrations (P > 0.33). These results suggest that while administration of bisphosphonate has no effect on growth morphometrics, its repetitive use alters PTH concentrations after two doses.Item Improving osseointegration of PEEK through surface textures(Montana State University - Bozeman, College of Engineering, 2019) Scott, Renn Patrick; Chairperson, Graduate Committee: Cecily RyanPEEK (Polyetheretherketone) is one of the most promising alternatives to titanium in cortical bone implants due to being biologically inert and having an elastic modulus similar to that of bone. It also has favorable reactions conducive to common medical imaging methods such as X-ray and magnetic resonance imaging (MRI) as compared to commonly used metals such as titanium and stainless steel. However PEEK is not inherently osseoconductive, leading to longer healing times and a greater chance of infection. Many different methods exist for improving osteoblast growth, such as the addition of bio-active materials like hydroxyapatite. Manipulating the surface texture of PEEK could provide better environments for cells to attach and can be used as another layer with other techniques, making the tissue interface more robust. The main objective of this project is to observe cell adhesion to a textured surface to identify cell preference for surface geometry as a first step to improve full integration of non-resorbable implants into bone tissue. The methods explored were also chosen for their repeatability, reliability and lack of chemical modification compared to other successful surface modulation techniques. The surface textures were embossed into PEEK using micro-etched aluminum molds. Textures vary in their shape, spacing, size, depth and surface convexity/concavity. The cell adhesion was recorded through fluorescent confocal microscopy and the cell-substrate interaction was observed under electron microscopy. The results were that 25 micron and 10 micron features discouraged cell adhesion while 325 micron and 120 micron features encouraged cell adhesion with pillars performing better than holes. The best feature was the 325x40 micron square pillars. With a cell volume to surface area ratio of 5.13, a live cell count of 276.5, a dead cell count of 9.00, and a non-dimensional distance to feature of 0.67.Item The elastic properties of bone by ultrasound(Montana State University - Bozeman, College of Engineering, 1985) LaMont, Donald Thompson; Chairperson, Graduate Committee: Michael K. Wells