Department of Biomedical Sciences (MU)https://hdl.handle.net/10355/53042024-03-28T09:01:48Z2024-03-28T09:01:48Z6-Thioguanine and zebularine globally demethylate a canine lyphoma cell lineFlesner, Brian K.https://hdl.handle.net/10355/458382021-01-05T19:11:02Z2014-01-01T00:00:00Z6-Thioguanine and zebularine globally demethylate a canine lyphoma cell line
Flesner, Brian K.
[ACCESS RESTRICTED TO THE UNIVERSITY OF MISSOURI AT AUTHOR'S REQUEST.] Epigenetic modifications of chromatin, including methylation, histone modifications, and protein chaperoning, play a significant role in the biology of cancer. In concert with mutations, epigenetic modifications alter gene expression and protein translation/activity to confer a neoplastic phenotype. Hypermethylation of tumor suppressor genes or hypomethylation of proto-oncogenes or oncogenes can abrogate cell-cycle controls. These processes are reversible, resulting in restoration of normal gene expression. Relationships between methylation aberrations in human NHL have already been made; work is yet to be done for canine lymphoma. Recent treatment alterations are now being directed at specific epigenetic changes. Many of the common epigenetic modifiers have previously been used in both humans and dogs. This lends drugs already proven to be safe available for research opportunities in vivo. The purpose of this research project is to determine if epigenetically-active drugs could result in phenotypic reversion in a canine lymphoma cell line. To test this, we evaluated a cells in vitro, exposing them to demethylating agents. Our end analysis was generation of cell proliferation and viability assays, quantitation of global methylation levels, and confirmation of demethylating drug targets. We hypothesized that canine lymphoma cells will undergo global demethylation in vitro after treatment with demethylating agents including 6-thioguanine (6-TG) and zebularine (Zeb). As in humans, 6-TG will downregulate DNMT- 1. The demethylating agents will have a dose dependent effect on global methylation and cell kill. The canine lymphoma cell line, CLGL-90, was grown in vitro with custom RPMI media using sterile techniques. The cells were treated with control (buffer solution), 6-TG, or Zeb in varying concentrations. Initial cell counts were collected prior to the drugs being added, and at 24 and 48-hour time points. Half of the originally plated cells were harvested for methylation analysis and cell survival analysis at 24 hours and replaced with appropriate media. The remaining cells were then re-treated and removed for analysis at 48 hours. Methylation analysis was HpaI/MspII (selective and non-selective methylation restriction enzymes) ratio. Western blot was used to determine DNMT1 protein levels before and after treatment. Cell survival curves were calculated using hemocytometer and trypan blue staining. The CLGL-90 cells were globally demethylated with increasing concentrations of 6-TG and Zeb. DNMT1 was reduced in cells treated with 6-TG and Zeb compared to controls, in a dose-dependent manner. Increasing concentrations of the demethylating agents also resulted in decreased cell survival, with 6-TG more effective than Zeb. 6-TG and Zeb globally demethylate the CLGL-90 canine lymphoma cell line and result in decreased amounts of DNMT-1 protein present. Increasing concentrations of the drugs also results in increasing cell kill. Future directions include in vitro work using these drugs in concert with cytotoxic chemotherapy drugs against resistant lymphoma cells. We also plan to begin using these agents in vivo, targeting resistant canine lymphoma patients in the clinic.
2014-01-01T00:00:00ZAcute and chronic adaptations to intermittent pnemuatic [sic] leg compressionsRoseguini, Bruno Tesinihttps://hdl.handle.net/10355/144732020-11-23T20:02:53Z2011-01-01T00:00:00ZAcute and chronic adaptations to intermittent pnemuatic [sic] leg compressions
Roseguini, Bruno Tesini
[ACCESS RESTRICTED TO THE UNIVERSITY OF MISSOURI AT REQUEST OF AUTHOR.] Few therapies exist that improve functional capacity and quality of life of patients with peripheral arterial disease (PAD). Despite the growing prevalence of this highly debilitating condition in the aging population, the currently available treatment options have a markedly low cost-effectiveness and accessibility. Application of intermittent pneumatic leg compressions (IPC) is emerging as a promising strategy for PAD but the mechanistic basis of action of this approach remains largely unknown. The studies described in this dissertation were designed to gain insights into the acute adjustments and long-term adaptations to IPC application. To accomplish these aims we developed a model in rodents that allowed us to study in depth the essential physiological responses to this therapy in healthy animals and in a preclinical model of peripheral arterial insufficiency. We conducted studies to investigate: 1) the impact of a single session of IPC on limb hemodynamics and skeletal muscle gene expression (Chapters 2 and 3) and 2) the long-term consequences of IPC on exercise tolerance, muscle blood flow, capillarization and oxidative capacity (Chapter 4). We also report the findings of our initial efforts to translate our findings in rodents to humans by studying the chronic effects on forearm compression on blood flow in healthy young subjects (Appendix). Collectively, these studies shed new light on the therapeutic potential of IPC for patients with PAD as well as on the possible mechanisms underlying the clinical benefits associated with this novel therapy.
Title from PDF of title page (University of Missouri--Columbia, viewed on May 31, 2012).; The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file.; Dissertation advisor: Dr. M. Harold Laughlin; Vita.; Includes bibliographical references.; Ph. D. University of Missouri-Columbia 2011.; "December 2011"
2011-01-01T00:00:00ZAnalysis of coffin and shoulder joint lameness with an inertial sensor-based system : impact versus pushoffAl Abidi, Adamhttps://hdl.handle.net/10355/152362020-11-22T04:44:38Z2012-01-01T00:00:00ZAnalysis of coffin and shoulder joint lameness with an inertial sensor-based system : impact versus pushoff
Al Abidi, Adam
Reason for performing the study: An inertial sensor-based system (Lameness Locator[copyright] [LL]) can help veterinarians detect mild lameness. It would be beneficial if this tool could also be used to distinguish lamenesses produced by lesions in different structures. Hypotheses: Coffin arthritis predominantly causes impact lameness while shoulder arthritis predominantly causes pushoff lameness. Objective: To investigate if shoulder arthritis causes pushoff lameness and coffin arthritis causes impact lameness and if these lamenesses can be differentiated by comparing the phase angle of the resultant ray calculated by the LL. Methods: Using a crossover design, coffin and shoulder arthritis were alternately induced in 12 horses with intra-articular injection of IL-1[beta]. Immediately before injection and every 6-12 h thereafter, the horses were evaluated with the LL. This evaluation was performed while the horses were trotted in hand in a straight line on a hard surface for about 120m. The phase angle (= arctangent [MINDIFF mean / MAXDIFF mean]) of each type of lameness (coffin or shoulder arthritis) were compared with the Wilcoxon signed-rank test using data from the last time point before lameness was no longer detectable. Results: No difference could be detected (p=0.625) between the phase angle when coffin (median, 81[degrees]; range, 58-123[degrees]) and shoulder arthritis (median, 86[degrees]; range, 59-104[degrees]) were compared. Conclusion: Coffin arthritis and shoulder arthritis did not consistently cause impact lameness and pushoff lameness, respectively.
Title from PDF of title page (University of Missouri--Columbia, viewed on September 10, 2012).; The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file.; Thesis advisor: Dr. Kevin Keegan; Includes bibliographical references.; M.S. University of Missouri-Columbia 2012.; "May 2012"
2012-01-01T00:00:00ZThe antiendotoxin effects of polymyxin B in a feline model of endotoxemiaSharp, Clairehttps://hdl.handle.net/10355/92982022-09-27T15:51:47Z2010-01-01T00:00:00ZThe antiendotoxin effects of polymyxin B in a feline model of endotoxemia
Sharp, Claire
Introduction: Directed, effective therapies for feline sepsis are needed to reduce the high morbidity and mortality associated with this disease. Materials and Methods: We investigated the anti-endotoxin effects of PMB in a blinded, placebo controlled fashion, both ex vivo in a feline whole blood culture system and in vivo, using a low-dose endotoxin infusion in cats (2ug/kg/hr IV x 4 hours). Serial measures of systemic inflammation, and hemodynamic stability, were compared between groups. Results: Ex vivo, PMB significantly decreased LPS-induced TNF production from whole blood. In vivo, endotoxin infusion resulted in the development of fever, hypotension, leucopenia and increased TNF activity. Polymyxin B (1mg/kg over 30 minutes) treatment decreased peak plasma TNF activity (p<0.001) and increased white blood cell count (p=0.019), with no adverse effects. Conclusions: Polymyxin B administration resulted in decreased peak plasma TNF activity and increased white blood cell count in this feline model of endotoxemia, with no adverse effects. Given the apparent safety and anti-endotoxin effects of PMB in this endotoxemia model, a carefully designed, randomized, blinded, placebo controlled clinical trial evaluating the use of PMB in naturally occurring Gram negative feline sepsis should be considered.
The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file.; Title from PDF of title page (University of Missouri--Columbia, viewed on November 9, 2010).; Thesis advisor: Carol Reinero.; "August 2010"; M.S. University of Missouri-Columbia 2010.
2010-01-01T00:00:00Z