Department: Comparative and Veterinary Medicine ![[clear]](close-x.png "Remove this limiter")
18 matches in the database.
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1.
Binjawadagi, Basavaraj.
Evaluation of immune correlates of protection against porcine reproductive and respiratory syndrome virus in pigs intranasally with adjuvnated vaccines.
Degree: MS, Comparative and Veterinary Medicine, 2012, Ohio State University
► Porcine reproductive and respiratory syndrome (PRRS) is an economically devastating disease of…
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▼ Porcine reproductive and respiratory syndrome (PRRS) is an economically devastating disease of pigs, caused by PRRS virus (PRRSV), incurring estimated $664 million losses annually to the US pork industry. As prevention measure, widely used modified live PRRSV vaccine (PRRS-MLV) has failed to completely protect pigs against genetically variant strains, and it is unsafe to use the same in pregnant sows due to potential vertical and horizontal transmission of the mutated vaccine virus. In contrast, inactivated PRRSV vaccines are safe but they have failed to protect against reinfections by even homologous strains. Therefore, developing a safe and protective PRRSV vaccine remained as a challenge. The primary site of PRRSV infection is the lungs and the virus enters through respiratory mucosal surfaces. Mucosal immunization strategy has the potential to elicit protective local and systemic immunity, while parenterally administered vaccines elicit weak mucosal immunity. Therefore, the aim of our research was to develop protective mucosal vaccines against PRRS. In this report, we are presenting results of two independent studies on live attenuated and killed PRRSV vaccines. Reactive oxygen species (ROS) are produced predominantly by phagocytic cells. Optimal levels of ROS have potent antimicrobial properties, while excessive production of ROS induces apoptosis/necrosis of infected as well as bystander cells, resulting in inflammatory pathology. Previously, we have shown that co-inoculation of pigs with PRRS-MLV with a potent mucosal adjuvant Mycobacterium tuberculosis whole-cell lysate (M. tb WCL), intranasally, induces superior cross-protective immunity. In this study, we have demonstrated that peripheral blood mononuclear cells (PBMCs) and bronchoalveolar lavage fluid (BAL) cells of PRRS-MLV plus M. tb WCL vaccinated PRRSV challenged pigs secreted reduced (but optimum) levels of ROS compared to unvaccinated virus challenged pigs, which secreted significantly higher amounts of ROS, associated with increased lung pathology. Thus, protective mucosal immunity induced using PRRS-MLV plus M. tb WCL protects pigs against RSO mediated lung pathology. Further, in our endeavor to develop a safe and protective killed vaccine, we reinforced the killed PRRSV vaccine in two ways; firstly by coupling it with M. tb WCL, and secondly to achieve the sustained vaccine delivery the killed viral antigens and adjuvant M. tb WCL were entrapped in PLGA [poly(lactideco- glycolide)] nanoparticles. Subsequently, the vaccine formulation was analyzed in vivo in pigs using different vaccine and adjuvant combinations. Our results indicated that, PLGA entrapped PRRSV killed vaccine adjuvanted with unentrapped M. tb WCL had a better cross-protective immunity to a virulent heterologous PRRSV strain MN184 challenge. The immune correlates of protection were demonstrated at both mucosal sites and systemically, characterized by: (1) higher levels of PRRSV specific IgG and IgA antibody response; (2) upregulated PRRSV specific neutralizing antibody titers; (3) complete clearance of viremia and replicating PRRSV from the lungs; and (4) enhanced frequency of IFN-γ secreting cells in the lungs. Results of our study are useful in developing a safe and protective PRRSV vaccine. In conclusion, our study for the first time, has demonstrated that co-administration of PLGA nanoparticles entrapped adjuvanted killed PRRSV vaccine with a potent mucosal adjuvant is capable of eliciting cross-protective immunity against PRRS in pigs.
Advisors/Committee Members: Gourapura, Dr. Renukaradhya.
Subjects: Immunology; Veterinary Services; Virology
Keywords: PRRSV; PLGA nanoparticles; WCL
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2.
Chaiwatpongsakorn, Supranee.
Soluble Respiratory Syncytial Virus Fusion Protein in the Fully Cleaved, Pretriggered State, a Tool to Study Protein Triggering.
Degree: PhD, Comparative and Veterinary Medicine, 2011, Ohio State University
► Respiratory syncytial virus (RSV), a member of the Paramyxoviridae family, Pneumovirinae subfamily…
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▼ Respiratory syncytial virus (RSV), a member of the Paramyxoviridae family, Pneumovirinae subfamily is the most significant respiratory pathogen in infants and second only to influenza virus in the elderly. Despite extensive efforts, no vaccines or small molecule antiviral drugs are available. The RSV fusion (F) glycoprotein has been a major target for vaccine and antiviral drug development because of its importance in the viral replication cycle, its conserved sequence and structure, its exposed position in the virion, and its strong immunogenicity. Like other paramyxoviruses, the RSV F protein is anchored in the virion membrane in a metastable, pretriggered form. Once triggered, the F protein undergoes a dramatic conformational extension that inserts its hydrophobic fusion peptide into the target cell membrane, then folds back on itself to bring the membranes together and initiate fusion. However, the Pneumovirinae F protein is unique in that it, alone, is sufficient to mediate membrane fusion and virus infection. It is, therefore, the simplest F protein to study. It likely has the ability to attach to target cells from which position it is triggered. Neither the trigger site on the F protein nor the triggering molecule/event has been identified. To begin to study the triggering mechanism of the RSV F protein biochemically, we have generated a soluble F (sF) protein by replacing the transmembrane and cytoplasmic tail domains with a 6His tag. This sF protein is secreted efficiently from 293T cells in a fully cleaved form. It is recognized by neutralizing monoclonal antibodies, appears spherical by electron microscopy, and is not aggregated, all consistent with a native, pretriggered trimer. The sF protein was purified on a Ni2+ column and eluted with 50 mM phosphate buffer containing 500 mM NaCl and 250 mM imidazole. Dialysis against 10 mM buffer caused the sF protein to trigger, forming “hatpin” shaped molecules that aggregated as rosettes, characteristic of the posttriggered form. Further dialysis experiments indicated that the efficiency of triggering correlated well with the reduction of buffer molarity. Reduction of buffer molarity by dilution also resulted in exposure of the fusion peptide as detected by liposome association, confirming sF protein triggering. Mutation of the furin cleavage site adjacent to the fusion peptide prevented liposome association, confirming that association is via the fusion peptide. Although it is not clear whether reduction in molarity can serve as a physiological trigger of the intact F protein during the natural infection of RSV, our study has revealed a novel, surrogate method for triggering a viral fusion protein. The availability of pretriggered RSV sF protein capable of being triggered and transformation into its posttriggered conformation enables studies of its mechanism of attachment, triggering, and refolding, a protein vaccine for adults, assays to quantify antibodies against F, discovery of the mechanism of action of drugs known to target F, and high throughput screens to identify new and better drugs against F.
Advisors/Committee Members: Peeples, Mark.
Subjects: Virology
Keywords: RSV; fusion protein; triggering
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3.
Creamer, Michelle.
UVB Exposure and Topical Estrogen Effects on the Development of Skin Cancer in a Pre- and Post-Menopausal Mouse Model.
Degree: MS, Comparative and Veterinary Medicine, 2012, Ohio State University
► Ultraviolet light (UV) is the most common complete carcinogen which we are…
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▼ Ultraviolet light (UV) is the most common complete carcinogen which we are exposed to on a daily basis that initiates and promotes tumor development and growth in the skin. Thus, multiple exposures to UV radiation from the sun can increase the incidence of skin cancer. Estrogen based hormone replacement therapy is now prescribed as a topical ointment. Estrogen, a known carcinogen, has been linked to increased risks of various reproductive systems cancers. Prior to this study, the effects of topical estrogen applied to sun exposed areas on the development of skin cancer had not been extensively studied. The specific aims of this study are twofold: (1) to determine the acute effects of topical estrogen on UVB induced inflammation, DNA damage, and repair and (2) to investigate the potential carcinogenic effect of topical estrogen on chronically UVB exposed skin in pre-menopausal and post-menopausal mouse models of human disease. We hypothesized that previously UVB irradiated skin treated with topical estrogen (10nmol) would result in increased inflammation and DNA damage acutely and ultimately result in increased tumor burden and severity. For the acute study, SKH1 mice were irradiated with UVB light once, treated topically with vehicle, Surgilube®, or estrogen and sacrificed at 24, 48, 72, or 96 hours (n=48). In the chronic study, mice were irradiated three times a week for 10 weeks (n=55). They were then randomized into two groups and underwent either surgical removal of their ovaries or a sham surgical procedure simulating pre- and post-menopausal conditions. These two groups were further randomized into 4 groups and treated topically with estrogen or Surgilube® three times a week for 15 weeks. Inflammatory mediators, myeloperoxidase, hydrogen peroxide, and prostaglandin E2 (PGE2) as well as markers of DNA damage, cyclobutane pyrimidine dimers and p53 were measured in the acute and chronic studies. Tumor growth was measured weekly in the chronically irradiated mice. The acute study data shows that topical treatment with estrogen did not alter UVB induced increases in hydrogen peroxide and PGE2. However topical estrogen treatment did appear to affect the infiltration of neutrophils into the skin following UVB exposure. This suggests that estrogen may play a role in modulating select inflammatory mediators when applied after UVB radiation. In the chronic study, there were no significant differences in the effects of estrogen in control or ovariectomized mice. However, estrogen treated mice developed more tumors of a higher grade compared to mice treated with Surgilube®. The results of this study suggest that estrogen may be increasing the severity of tumors through the inhibition of DNA repair as shown by the decreased levels of p53 in the skin surrounding tumors with increased levels of p53 in the actual tumors. Although the results of this study did not reach statistical significance, the clinical relevancy of developing more malignant versus benign neoplasms with topical estrogen treatment is important. Future studies are needed to investigate biological causes for the increased severity of neoplasms in SKH1 mice treated with topical estrogen.
Advisors/Committee Members: Oberyszyn, Tatiana.
Subjects: Biomedical Research
Keywords: UVB, skin cancer, estrogen, SKH1
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4.
Dardenne, Adrienne.
High Mobility Group Box-1 (HMGB-1) Induces Scar Formation in Early Fetal Wounds.
Degree: MS, Comparative and Veterinary Medicine, 2012, Ohio State University
► Previous studies have shown that inflammation is a key factor in determining…
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▼ Previous studies have shown that inflammation is a key factor in determining scar formation in cutaneous fetal wounds. In a fetal mouse model, sterile wounds generated on embryonic day 15 (E15) have little to no inflammation and heal scarlessly, while wounds generated on embryonic day 18 (E18) have inflammation and heal with a scar. The mechanisms leading to age-related differences in inflammation and healing are not fully understood. Alarmins, which comprise a group of endogenous danger signals, have been implicated in promoting inflammation in various organ systems and disease processes. This study evaluates the role of a specific alarmin, high mobility group box 1 (HMGB-1), in cutaneous fetal wound healing. HMGB-1 is a non-histone architectural DNA binding protein localized within the nucleus of the cell. However, it can be released by both passive and active mechanisms. Passive release into the extracellular matrix occurs as a result of cell injury or necrosis. While active secretion is described as a capability of several cell types, including immune cells. Once in the extracellular space, HMGB-1 stimulates inflammation by binding to RAGE (receptor for advanced glycation end products) or toll-like receptors present on inflammatory cells. This is the first study to evaluate the role of HMGB-1 in the process of fetal wound healing. We hypothesized that alterations in the expression or release of HMGB-1 between early and late gestation fetal wounds contribute to the differences seen in healing outcomes. To begin, comparisons of HMGB-1 expression in fetal wounds that heal scarlessly and wounds that heal by scar formation were made. Later experiments tested the ability of HMGB-1 to induce scar formation in E15 wounds that have previously been shown to heal scarlessly. Finally, mechanisms of action were explored to decipher how HMGB-1 affects fibroblasts, the cells ultimately responsible for scar formation. Immunohistochemical staining of E15 and E18 skin revealed age-related differences in HMGB-1 expression patterns in both unwounded and wounded skin. As compared to E15 basal keratinocytes, basal keratinocytes of E18 skin expressed higher nuclear HMGB-1 staining and demonstrated a more substantial loss of nuclear staining after injury, suggesting that HMGB-1 is released to a greater extent in E18 wounds. Furthermore, E15 wounds treated with HMGB-1 could be induced to heal by fibrosis with differences seen in both the amount and quality of collagen present within the scar. Age-dependent differential release of HMGB-1 from fetal keratinocytes during wound healing and the capability of HMGB-1 to induce scar formation in E15 wounds that naturally heal scarlessly were found. These results support the hypothesis that alterations in expression or release of HMGB-1 contribute to the difference seen in healing outcome between early and late fetal wounds. This study suggests both the timing and degree of extracellular HMGB-1 release are potential factors in determining whether scarless or fibrotic wound healing will result. In light of these findings, HMGB-1 remains a viable therapeutic target for optimizing wound repair.
Advisors/Committee Members: Wilgus, Traci.
Subjects: Biomedical Research; Medicine
Keywords: high mobility group box 1; HMGB-1; fetal wound healing
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5.
Dulin, Jennifer Anne.
Influence of Exercise on the Distribution of 99mTechnetium-Methylene Diphosphonate Following Intra-articular Injection in Horses.
Degree: MS, Comparative and Veterinary Medicine, 2011, Ohio State University
► Objective: To determine the effects of exercise on the distribution and pharmacokinetic…
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▼ Objective: To determine the effects of exercise on the distribution and pharmacokinetic parameters of 99mtechnetium-methylene diphosphonate (99mTc-MDP) following intra-articular (IA) injection in horses. Animals: 5 horses. Procedures: In this randomized, controlled, crossover study, one antebrachiocarpal joint (ACJ) per horse was assigned to the Exercised group (n=5), and the contralateral ACJ was evaluated in the Non-Exercised group (n=5) after a minimum of 7 days. Following IA injection of 99mTc-MDP (148 MBq), blood and scintigraphic images of the carpus were obtained at 5, 10, 15, 20, 25, 30, 45, 60, 90, 120, 240, 360, 480, 600, 720, and 1440 minutes. Plasma and scintigraphic radioactivity were determined over time, and pharmacokinetic parameters were generated via non-compartmental and compartmental analyses. Each horse was monitored by physical and lameness examination and ACJ synovial fluid analysis before injection and at days 1, 2, 3, and 7. Results: Lameness was not observed. Mean synovial fluid WBC count increased at day 1 (Exercised: 721 ± 234 cells/uL, p < 0.05; Non-Exercised: 948 ± 223 cells/uL, p < 0.01), but returned to baseline at days 3 and 7. Mean time to maximum plasma radioactivity was earlier in the Exercised group (16.00 ± 2.35 min) than the Non-Exercised group (43.75 ± 3.64 min) (p < 0.001). Linear regression of the scintigraphic radioactivity-time curves showed a greater negative slope in the Exercised group within the first 25 minutes (p = 0.03). There was no difference in absorption or elimination rate constants in a 2-compartment model. Conclusions and Clinical Relevance: Intra-articular 99mTc-MDP was safe and effective for evaluating synovial solute distribution. Exercise significantly increased early transfer of 99mTc-MDP from the ACJ into plasma, although absorption and elimination rate constants were not affected. Exercise may affect synovial clearance and withdrawal times of IA medications.
Advisors/Committee Members: Bertone, Alicia.
Subjects: Animal Diseases; Pharmacology; Radiology; Sports Medicine; Veterinary Services
Keywords: pharmacokinetics; exercise physiology; horse; technetium
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6.
Francis, Kyle Andrew.
Measurement of the Feline Hippocampus Using Magnetic Resonance Imaging.
Degree: MS, Comparative and Veterinary Medicine, 2011, Ohio State University
► The human hippocampus has several unique attributes and is one of the…
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▼ The human hippocampus has several unique attributes and is one of the more structurally discrete structures of the limbic system. Humans exposed to chronic stress or pain, most notably patients with posttraumatic stress disorder and chronic pelvic pain syndromes, have detectably smaller hippocampal structures. Interstitial cystitis (IC) in humans is a recognized syndrome of chronic pelvic pain. Feline interstitial cystitis (FIC) is a spontaneous animal model for IC. Therefore, documenting volume changes in the hippocampus in cats may lead to further understanding of chronic pain in all species. The aim of this study is to evaluate the feasibility of measuring the volume of the feline hippocampus using magnetic resonance imaging (MRI). Brain MRI of 3 cats (2 nonsymptomatic cats from an FIC colony and 1 normal cat from an unrelated study) was performed using 3 Tesla (T) and 7T MR systems. T2w images were made with extremity coils designed specifically for each magnet, and a smaller surface coil in the 7T magnet. Transverse, sagittal, and dorsal plane images were acquired in each imaging session. Cats were imaged in vivo, post perfusion fixation, and at various durations (4-181 days) of immersion fixation of the brain in 10% formalin using both magnets. DICOM images were imported into ImageJ and each hippocampus was manually outlined on all images. The areas were then multiplied by the image thickness (including spacing) and the area from each slice was summed to obtain a volume. The average measured in vivo hippocampal volume was 277.2 + 18.9 mm3 on the transverse images of the 3T system which equated to 1% of the total brain volume (each hippocampus). The average volumes obtained in the 3T system in the other planes were 228.0 + 47.2 mm3 on the sagittal images and 207.0 + 47.5 mm3 on the dorsal images. Average volumes obtained in vivo in the 7T system were 286.8 + 47.1 mm3 on the transverse images, 221.5 + 41.0 mm3 on the sagittal images, and 273.5 + 9.5 mm3 on the dorsal images. Detection of changes in volume of the hippocampus using MRI is possible in populations of cats, but not likely to be useful in individuals.
Advisors/Committee Members: Drost, Wm Tod.
Subjects: Veterinary Services
Keywords: MRI, magnetic resonance imaging, hippocampus, feline, cat, FIC
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7.
Haines, Robyn A.
Development and Characterization of Early Immunological Events of a Rabbit Model of Milk-Borne Transmission of Human T-Lymphotropic Virus Type 1 Infection.
Degree: PhD, Comparative and Veterinary Medicine, 2012, Ohio State University
► The complex retrovirus Human T-lymphotropic virus type-1 (HTLV-1) is the causative agent…
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▼ The complex retrovirus Human T-lymphotropic virus type-1 (HTLV-1) is the causative agent of adult T-cell leukemia/lymphoma and other lymphocyte-mediated inflammatory disorders. In endemic regions, HTLV-1 is primarily spread from mother to child through infected breast milk. The establishment of persistent HTLV-1 infection following the ingestion of infected lymphocytes is determined by the delicate balance between viral spread and the host immune response. The immunopathogenesis of these early events is not completely understood, and advances in this area have been hindered by the lack of an appropriate animal model. This thesis describes a novel rabbit model of HTLV-1 milk-borne infections, and provides data to understand the early immunological and virological events following oral mucosal exposure to HTLV-1. Herein, we performed an extensive examination of the rabbit gut-associated lymphoid tissue. Using two quantitative methods to exam lymphocyte subsets within the major inductive sites our data revealed similarities between rabbits and humans. This information validates this species as a model for mucosal immunology studies following oral exposure to HTLV-1 and establishes reference ranges for future studies. Our data provides important knowledge of the immune response against HTLV-1 infection following oral exposure to infected lymphocytes. We established a protocol for infection via the oral mucosal route using a method that mimics infant exposure to repeated doses of comparable numbers of infected lymphocytes. We further characterized this model of infection through evaluation of humoral and cellular immune responses and viral parameters. We determined that rabbits exposed orally to HTLV-1 infected lymphocytes develop a persistent infection characterized by a delayed and variable humoral immune response similar to infected infants. Rabbits exposed by this route also displayed a variable, decreased and delayed peripheral cellular immune response with lower and variable proviral loads and p19 antigen production from ex vivo cultured peripheral blood mononuclear cells when compared to rabbits infected by the intravenous route. This animal model of HTLV-1 infection was used to study early spatial and temporal events following mucosal viral infection. Our data indicates that oral inoculation with HTLV-1 infected lymphocytes results in systemic virus distribution by four weeks post inoculation. Early viral reservoirs include the spleen, mesenteric lymph node, and gut-associated lymphoid tissues (GALT). Within the GALT, there is quiescent integrated provirus within the effector sites and mesenteric lymph node, and actively replicating virus within the inductive sites and spleen. Collectively, data presented in this thesis indicates that HTLV-1 infection following oral exposure induces a delayed and decreased systemic immune response to viral exposure. Our data indicates that the events associated with development of HTLV-1 persistent infections following milk-borne transmission occur below the level of detection within tissue compartments for the first four weeks following exposure, prior to systemic spread.
Advisors/Committee Members: Neiweisk, Stefan.
Subjects: Immunology; Virology
Keywords: HTLV-1; Rabbit; Mother to child transmission; Oral transmission, Mucosal Immunology
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8.
Karnik, Ketaki.
Accuracy of Computed Tomography in Determining Lesion Size in Canine Osteosarcoma of the Appendicular Skeleton.
Degree: MS, Comparative and Veterinary Medicine, 2011, Ohio State University
► Multidetector contrast enhanced computed tomography with acquisition of 0.625 mm thick axial…
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▼ Multidetector contrast enhanced computed tomography with acquisition of 0.625 mm thick axial transverse images was used to measure the extent of appendicular osteosarcoma (OSA) in 10 dogs. The measured length of tumor based on CT was compared to the true length of tumor using histopathology. There was good correlation of the true length of OSA compared to the length of intramedullary/endosteal abnormalities on CT with a mean overestimation of 1.8% (SD = 15%). There was poor correlation of the true length of OSA compared to the length of periosteal proliferation on CT with a mean overestimation of 9.7% (SD = 30.3%). There was poor correlation of the true length of OSA compared to the length of abnormal contrast enhancement by 9.6% (SD = 34.8%). The measured extent of intramedullary/endosteal abnormalities using sub-millimeter thick axial transverse acquisition of images with multidetector CT should be of value in assessing patient candidacy and surgical margins for limb spare surgery. It may also be useful for evaluating response to therapy in dogs that receive chemotherapy or radiation therapy when surgery is not performed.
Advisors/Committee Members: Green, E.
Subjects: Animal Diseases; Animals; Animal Sciences; Medical Imaging; Medicine; Veterinary Services
Keywords: CT; computed tomography; OSA; osteosarcoma; multidetector; appendicular; canine; dog; neoplasia; bone
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9.
Kent, Agnieszka Magdalena.
Effects of Atenolol, Ivabradine and Pimobendan on Left Atrial and Left Atrial Appendage Function: An Echocardiographic Study in Healthy Cats.
Degree: MS, Comparative and Veterinary Medicine, 2011, Ohio State University
► Left atrial (LA) and left atrial appendage (LAA) size and function can…
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▼ Left atrial (LA) and left atrial appendage (LAA) size and function can be altered in cats with cardiac disease. Decreased LA or LAA function and increased LA size are proposed risk factors for the development of thrombi within these chambers, which subsequently can result in arterial thromboembolism. Reduced LA function can also impair cardiac output, particularly when there is concurrent left ventricular diastolic dysfunction or reduced compliance. Although LA dysfunction has been reported in cats with cardiomyopathy, there are limited data regarding the effects of drugs on LA function in cats. The purpose of this echocardiographic study was to evaluate the effects of atenolol, pimobendan, and ivabradine on indices of LA function in healthy cats. This prospective study used a double-blind, fully-crossed design in 9 healthy, sedated cats. LA function was evaluated by echocardiography over four study periods: control, atenolol (1.8-2.5 mg/kg q12h), pimobendan (0.2-0.3 mg/kg q12h), and ivabradine (0.3-0.5 mg/kg q12h). Treatments were randomized and continued for 7 days prior to measurements. Heart rate along with the following indices of LA and left ventricular (LV) size and function were evaluated: LA diameter, area and volume at end-systole and end-diastole; LA shortening fraction (SF), shortening area (SA) and ejection fraction (EF); peak LAA inflow and outflow velocities; atrial reversal wave velocity (ARR) and duration (ARD); LV internal dimension at end-diastole and end-systole; LV shortening fraction and isovolumic relaxation time. Treatments were compared by repeated measures ANOVA followed by Holm Sidak multiple-comparison test. A linear mixed model (LMM) was performed to evaluate the effect of individual cats on LA function variables. Statistical significance was p<0.05. Pimobendan significantly decreased end-diastolic variables of LA size while having minimal effects on LA and LAA function. Ivabradine significantly decreased LAA-inflow velocities (mean change of –21 cm/s, p<0.05) but otherwise had minimal effects. Atenolol significantly decreased (p<0.05) LA SA, EF, LAA inflow and outflow, and the ARR, and increased the ARD. HR was significantly decreased following atenolol and ivabradine (p<0.001). Subject had minimal influence on study variables. These findings indicate that in these healthy cats pimobendan reduces LA size while having minimal effects on LA and LAA function. Ivabradine has minimal effects on LA and LAA function, while atenolol impairs LA and LAA function. Additional studies in cats with naturally occurring cardiac disease are warranted.
Advisors/Committee Members: Bonagura, John.
Subjects: Veterinary Services
Keywords: Left atrium; left atrial appendage; function; cats; echocardiography
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10.
Leise, Britta S.
Laminar Inflammation and the Equine Epidermal Epithelial Cell: Determining the Role in Laminar Failure.
Degree: PhD, Comparative and Veterinary Medicine, 2010, Ohio State University
► Laminitis is a devastatingly painful, life-threatening disease of the equine digit. Initiating…
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▼ Laminitis is a devastatingly painful, life-threatening disease of the equine digit. Initiating causes include sepsis/systemic inflammatory response syndrome (SIRS) related conditions, metabolic syndrome/endocrine dysfunction, and severe contralateral limb lameness. The pathogenesis of laminitis has yet to be completely elucidated; however, several theories on the predominate mechanism exist. Recent evidence shows a prominent proinflammatory response very early in the developmental phases of laminitis induced experimentally by administration of black walnut extract (BWE). As dysregulation of the inflammatory response is suspected to play an important role in sepsis/SIRS and subsequent multiple organ failure in humans, a similar mechanism has been proposed to occur in the horse, with the hoof being the predominate organ that fails. Laminar failure occurs when there is dysadhesion between the epidermal and dermal lamina at the basement membrane. The studies conducted were performed to determine if inflammation in the front and hind limb lamina occur after administration of a carbohydrate overload (CHO), which is a model that more closely resembles clinical cases of laminitis occurring from sepsis, to determine if phosphorylation of STAT proteins play a role in the inflammatory response of the lamina, and to determine if other organs have a similar inflammatory response as the lamina after CHO administration. Additional studies were performed to develop an understanding of how the equine epidermal cell responds to bacterial ligands known to be produced in the cecum after CHO administration and to develop a technique for isolation of RNA specifically from the equine laminar basal epithelial cell (LBEC) using laser capture microdissection (LCM). Results of these studies demonstrate that inflammation does occur in the front and hind lamina after CHO administration; however, the response occurs at the onset of lameness in these horses which is different from the BWE model where it occurs at the early developmental phase. STAT3, but not STAT1, phosphorylation occurs in the lamina and is most likely a direct result of the profound IL-6 response that has been documented to occur in the lamina from horses receiving both BWE and CHO. Inflammation does occur in the liver, lung and kidney after CHO administration; however, a different pattern of inflammatory gene expression occurs in each tissue with the lamina overall having the greatest response of any organ evaluated. Equine epidermal epithelial cells in culture respond to the gram negative bacterial components, LPS and flagellin, by producing proinflammatory cytokines, but do not response to the bacterial component of gram positive organisms, which is similar to what is observed clinically where horses with sepsis resulting from a gram negative source are much more likely to develop laminitis. Overall, inflammation appears to be involved in the development of laminitis. In addition, it is likely the laminar epithelial cell plays a much more active role, not only structurally but also producing and responding to inflammatory mediators. The methods developed to isolate RNA from the LCM technique will allow for extensive study of these cells in context of disease, thereby providing essential information from future studies.
Advisors/Committee Members: Belknap, James.
Subjects: Veterinary Services
Keywords: laminitis; horse; equine; inflammation; keratinocyte; laminar epithelial cell; gene expression
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11.
McCleese, Jennifer Kay.
Investigating the Biological and Biochemical Consequences of Met Function and Dysfunction in Canine Osteosarcoma.
Degree: PhD, Comparative and Veterinary Medicine, 2011, Ohio State University
► Osteosarcoma (OSA) is the most common malignant bone tumor in children and…
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▼ Osteosarcoma (OSA) is the most common malignant bone tumor in children and dogs. Currently, 30-40% of children and greater than 90% of dogs succumb to the disease following treatment. The receptor tyrosine kinase (RTK) Met has emerged as a potential target for therapeutic intervention for OSA. Met overexpression in human OSA is associated with a more aggressive phenotype and poor survival, and aberrant expression in normal human osteoblasts induces malignant transformation. The purpose of this work was to evaluate Met as a target for therapeutic intervention in OSA. The first objective was to determine if Met interacts with heat shock protein 90 (Hsp90) in OSA and evaluate a novel Hsp90 inhibitor, STA-1474, for OSA treatment. Hsp90 associated with co-chaperones in canine OSA cells but not normal canine osteoblasts, indicating formation of an active superchaperone complex in malignant versus normal tissue. STA-1474 promoted loss of cell proliferation, apoptosis, and induction of Hsp70. STA-1474 treatment also resulted in the down-regulation of HGF (hepatocyte growth factor) induced p-Met/Met, p-STAT3, and p-Akt/Akt. These data suggest that STA-1474 may be useful for the treatment of OSA. The second objective was to determine whether RTKs Met, epidermal growth factor receptor (EGFR), and Recepteur d'origine nantais (Ron) interact in OSA and explore the functional consequences of such interactions. EGFR and Ron phosphorylation was present in canine OSA tumor tissues, and Met was associated with EGFR and Ron in canine OSA cell lines. High Ron expression was prognostic for survival. Gefitinib (small molecule EGFR inhibitor) and crizotinib (small molecule Met inhibitor) inhibited OSA cell proliferation in an additive manner. Prolonged TGF alpha exposure promoted Met phosphorylation. Co-activation of EGFR and Met with their ligands resulted in amplified ERK1/2 and STAT3 phosphorylation. These data indicate that Met, Ron, and EGFR functionally interact in canine OSA, altering the manner in which these cells respond to growth factor stimulation. The final objective involved characterization of a germline Met point mutation (G966S) identified in 75% of Rottweilers, a breed at high risk for OSA. NIH3T3 cells stably transduced with G966S canine Met demonstrated greater scattering which was enhanced with HGF and blocked by a Met inhibitor, indicating these changes were directly related to Met expression and signaling. These cells also exhibited nonstimulated basal Met autophosphorylation. As reagents to study canine signal transduction pathways are limited, NIH3T3 cells were stably transduced with the equivalent mouse Met mutation (G963S). The G963S transduced cells exhibited enhanced matrix metalloproteinase 2 (MMP2) activity. Genomic integration of the Met construct was evident, but not gene expression based on cDNA analysis. CMV promoter methylation was suspected. Stably transduced 293TN cells expressing the Met construct based on analysis of cDNA were generated. In summary, these studies support targeting Met for the treatment of canine OSA. Interaction between Met and the RTK’s EGFR and Ron represents a novel finding in canine OSA and indicates that simultaneous targeting of all of these receptors may be beneficial. Further work will assess the G966S canine Met mutation contribution to OSA development in the Rottweiler.
Advisors/Committee Members: London, Cheryl.
Subjects: Oncology
Keywords: Canine Osteosarcoma; Met; EGFR; Ron; Receptor Tyrosine Kinase; Hsp90
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12.
Mercurio, Andrew David.
Effects of Extensive Periosteal Stripping on the Microstructure and Mechanical Properties of Cortical Bone.
Degree: MS, Comparative and Veterinary Medicine, 2011, Ohio State University
► The periosteum is a thin connective tissue layer that covers the external…
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▼ The periosteum is a thin connective tissue layer that covers the external surfaces of most bones and is essential to normal cortical bone biology. Periosteal stripping (PS) is a significant risk factor for post-radiation pathologic fracture following surgery for extremity soft tissue sarcomas. The purpose of this study was to determine the effects of PS on cortical bone structure and mechanical properties. 62 adult female mice underwent PS (N=32) or sham surgery (N=30) on the left femur. For PS, the periosteum was circumferentially removed from an 8-mm segment of the mid-diaphysis. For sham surgery, the bone was isolated without manipulation. At 2, 6, 12, or 26 weeks following surgery, the left femora were examined by micro-CT. Cortical thickness (CtTh), cross-sectional area (CSA), bone volume (BV) and polar moment of inertia (PMI) were measured from the mid-diaphysis. 3-point mechanical bend testing was performed and peak load (PL), stiffness and energy to failure (EF) were determined. Data from the groups were compared at each time point using a Student’s T-test (p<0.05), and two-way ANOVA was used to examine the parameters. PS resulted in significantly decreased CtTh, CSA, BV and PMI at all time points. PS resulted in significantly decreased PL, stiffness, and EF at 2 weeks, with further decreases at 6 and 12 weeks. There were no significant differences in mechanical properties between the two groups at 26 weeks. Correlation analysis revealed strong and significant relationships between microstructural and mechanical parameters. In conclusion, extensive PS causes early and significant decreases in cortical bone structural and mechanical properties, with eventual recovery of strength.
Advisors/Committee Members: Allen, Matthew.
Subjects: Biomedical Research
Keywords: mouse; animal model; periosteum; micro-CT; fragility
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13.
Mollenkopf, Dixie Francis.
Epidemiology of CTX-M cephalosporinase-bearing Escherichia coli and Salmonella spp. isolated from US livestock.
Degree: MS, Comparative and Veterinary Medicine, 2012, Ohio State University
► blaCTX-M β-lactamases confer resistance to critically important cephalosporin drugs. Recovered from both…
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▼ blaCTX-M β-lactamases confer resistance to critically important cephalosporin drugs. Recovered from both hospital and community-acquired infections, blaCTX-M was first reported in US livestock in 2010. It has been hypothesized that veterinary use of cephalosporins in livestock populations may lead to the dissemination of β-lactamase encoding genes. Therefore, our objectives were to estimate the frequency and distribution of coliform bacteria harboring blaCTX-M in the fecal flora of Ohio dairy cattle populations. In addition, we characterized the CTX-M alleles carried by the isolates, their plasmidic contexts, and the genetic diversity of the bacterial isolates themselves. We also evaluated the association between ceftiofur use and the likelihood of recovering cephalosporinase-producing bacteria. Thirty fresh fecal samples and owner-reported ceftiofur use data were collected from each of 25 Ohio dairy farms. Fecal samples (n=747) yielded 70 blaCTX-M positive E. coli from 5/25 herds, 715 blaCMY-2 E. coli from 25/25 herds and 274 Salmonella spp. from 20/25 herds. The within-herd prevalence of blaCTX-M positive herds ranged from 3.3 to 100 % of samples. Multiple PFGE patterns, plasmid replicon types and CTX-M genes were detected. Plasmids encoding CTX-M-1, -15, and -14 alleles were clonal by RFLP within herds and specific plasmid incompatibility group markers were consistently associated with each blaCTX-M allele. PFGE of total bacterial DNA showed similar within-herd clustering with the exception of one herd, which revealed at least 6 different PFGE signatures. We were unable to detect an association between owner-reported ceftiofur use and the probability of recovering E. coli carrying blaCTX-M or blaCMY-2.
Advisors/Committee Members: Wittum, Thomas.
Subjects: Epidemiology
Keywords: CTX-M, livestock, dairy, resistance, cephalosporin
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14.
Pentecost, Rebecca Lynne.
Vertical transmission of Mycoplasma haemolamae in alpacas (Vicugna pacos).
Degree: MS, Comparative and Veterinary Medicine, 2012, Ohio State University
► Mycoplasma haemolamae is a parasite with tropism for the red blood cells…
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▼ Mycoplasma haemolamae is a parasite with tropism for the red blood cells of alpacas, llamas, and guanacos. Transmission of the parasite likely occurs via an insect vector although the vector has not been elucidated to date. Transmission via blood transfusion has been demonstrated experimentally. In utero infection has been suggested and later demonstrated in a limited number of cases. The purpose of this study was to 1) determine the frequency of vertical transmission of Mycoplasma haemolamae from dam to cria; 2) determine whether colostral transmission of M. haemolamae occurs; and 3) provide preliminary data on colostral M. haemolamae specific antibody from pregnant alpacas on a farm with known prevalence of infection. Mycoplasma haemolamae specific PCR was performed on blood and colostrum from pregnant alpacas and their cria (n=52 pairs). Indirect fluorescent antibody testing was performed on a subset (n=43) of these colostrum samples. Total immunoglobulin concentrations of colostrum and cria sera and M. haemolamae specific IgG (prior to and after ingesting colostrum) were determined by turbidometric immunoassay and indirect fluorescence antibody testing, respectively. Sixteen of 52 dams (30.7%) pre-partum and one of 52 cria post-partum (1.9%; prior to ingestion of colostrum) were PCR positive for M. haemolamae, while 36/52 dams (69%) and 51/52 cria (98%) tested negative for M. haemolamae by PCR. All 43 colostrum samples and 52 of 52 post colostrum cria blood samples (100%) were negative by PCR. The dam giving birth to the M. haemolamae PCR positive cria was PCR negative. Statistically, it was no more likely for a PCR positive dam to give birth to a M. haemolamae, PCR positive cria (prior to colostrum ingestion) than a PCR negative dam (p=0.3077). M. haemolamae specific IgG was detectable in 22 of 43 (51%) of colostrum samples at a 1:10 dilution and 14 of the 22 positive 1:10 dilution samples (32.6% of the total samples) at a 1:100 dilution. There was no relationship between the PCR status of the dam and whether or not M. haemolamae specific antibodies were present in colostrum. Among the animals tested, in utero transmission of M. haemolamae was rare (1/52 pre-colostral alpaca cria), and all colostrum samples were negative for M. haemolamae by PCR. These data indicate that colostrum from positive dams is unlikely to harbor this parasite and therefore does not serve as a source of infection to newborn cria. Colostrum derived from both PCR positive and negative dams contained M. haemolamae specific antibodies. Our findings suggest that M. haemolamae specific antibodies may play a role in immunity to this hemoparasite; however, challenge studies are necessary to fully evaluate the role of M. haemolamae specific antibodies. Furthermore, antibody prevalence and detectable titers may provide different estimates than those available from current PCR based prevalence studies. Our findings also confirm that M. haemolamae isolates from geographically distinct regions do not differ significantly from each other.
Advisors/Committee Members: Lakritz, Jeffrey.
Subjects: Parasitology
Keywords: alpaca; Mycoplasma haemolamae; vertical transmission
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15.
Stoute, Simone Tricia.
Molecular Epidemiology and Pathogenicity of the Very Virulent Infectious Bursal Disease Pathotype in United States Poultry.
Degree: PhD, Comparative and Veterinary Medicine, 2012, Ohio State University
► Infectious bursal disease (IBD) was first recognized in 1962 and is presently…
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▼ Infectious bursal disease (IBD) was first recognized in 1962 and is presently one of the most economically significant immunosuppressive diseases affecting most poultry producing regions worldwide. The most severe form of the disease in terms of severity of clinical signs, lesions and mortality rate is the very virulent (vv) IBD. This very virulent pathotype can result in mortality rates as high as 100% in fully susceptible flocks. While classic and variant strains of the virus are endemic in the U.S., there were no reports of vvIBDV in poultry in the U.S. until 2009. Subsequent to the emergence of vvIBDV in U.S. poultry, several IBDV reassortant viruses have been detected from commercial and backyard chicken flocks within the U.S. These reassortant viruses have all been isolated from commercial or backyard chicken flocks in the State of California. Reverse transcriptase- polymerase chain reaction (RT-PCR) tests and sequencing on bursal tissues collected from field cases originating from California poultry have detected multiple vvIBDV reassortants. These include interserotypic reassortants with the genome segment A matching the vvIBDV pathotype and genome segment B characteristic of a serotype 2 IBDV (ID: K669, CA-K758, CA-D495). An interserotypic reassortant (ID: D2712) with a serotype 2 segment A and serotype 1 segment B was also identified in 5 week old commercial turkeys in 2012. A vvIBDV reassortant with genome segment A homologous to vvIBDV and genome segment B that aligned with serotype 1 classic IBDV strains from Australia was isolated (ID: 7741) in backyard brown leghorns in 2010. The first investigation described in chapter 2 assessed the pathogenicity induced by co-infection with very virulent infectious bursal disease virus (vvIBDV: rB strain) and U.S. endemic IBDV pathotype in specific pathogenic free leghorns. The severity of disease in co-challenged birds was compared to the disease induced by infection with the vvIBDV (rB strain) alone. Four wk old and 6 wk old birds were challenged oronasally with 105EID50 vv (rB strain) and 105EID50 of either a standard classic IBDV (STC strain), subclinical variant IBDV (Delaware-E strain), subclinical variant IBDV (T1 strain) or avirulent serotype 2 IBDV (OH strain). The severity of disease was assessed by comparing the 5-day mortality rates, severity of bursal lesions (mean bursal lesion scores) and mean bursal body weights (BBW) in each of the challenged groups. A mortality rate of 100% was observed in both 4 wk and 6 wk old birds inoculated with only the vvIBDV (rB) strain. A relative reduction in the mortality and severity of disease was observed in all groups co-challenged with rB and the second less virulent pathotypes (STC, Del-E, T1, OH) in both 4 wk and 6 wk old birds. Co-challenge with rB and the Del-E, T1 and OH strains resulted in a more significant decrease in mortality compared to challenge with the two antigenically similar pathogenic strains, rB and STC. Viral interference between the different pathotypes was hypothesized as the etiology of the reduction in severity of disease in co-challenged birds.
Advisors/Committee Members: Jackwood, Daral.
Subjects: Virology
Keywords: very virulent infectious bursal disease; reassortants; epidemiology; pathogenicity
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16.
Werbeck, Jillian Lee.
Genetic Contributions of the Tumor Microenvironment in Breast Cancer Metastasis.
Degree: PhD, Comparative and Veterinary Medicine, 2011, Ohio State University
► Breast cancer is the second leading cause of cancer-related deaths in women…
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▼ Breast cancer is the second leading cause of cancer-related deaths in women in the United States. Despite recent advancements in the diagnosis and treatment for breast cancer, metastasis is still the most lethal complication of this disease. Advancements in the field of breast cancer research are challenged by the availability of reliable animal models which can faithfully recapitulate human disease. Furthermore, over the past decade there have been numerous discoveries that have implicated the tumor stroma as an active and critical contributor to breast cancer pathogenesis. The purpose of this body of work was to characterize mouse models of breast cancer metastasis, to investigate the genetic contributions of fibroblasts in metastasis, to evaluate the role of paracrine signaling in the tumor microenvironment in breast cancer metastasis, and to review methods to model the role of the tumor microenvironment in vitro and in vivo. The first objective was to characterize the widely used mouse mammary tumor virus-Polyoma middle-T (MMTV-PymT) breast cancer model (Met-1 cells) in the context of breast cancer metastasis. The tumor microenvironment affected the morphology and gene expression of Met-1 breast cancer cells depending on the site of growth or metastasis. Therefore, this study demonstrated the active role of the tumor microenvironment in breast cancer metastasis and that the injection model can affect metastatic potential of breast cancer cells. The second objective was to investigate the role of a transcription factor (Ets2) in the lung tumor microenvironment in breast cancer metastasis. The deletion of Ets2 in lung fibroblasts reduced tumor burden and increased survival of mice injected with Met-1 breast cancer cells. Also, a novel Ets2-tumor-associated fibroblast (TAF) gene signature was identified which can retrospectively predict survival in human breast cancer patients. The third objective was to evaluate the role of autocrine and paracrine IL-6 with estrogen in the bone tumor microenvironment. Estrogen receptor-positive MCF-7 cells formed mixed osteoblastic and osteolytic tumors in the bone following intratibial injection. Furthermore, total bone and bone density was decreased in MCF-7 tumors independent of estrogen or IL-6 supplementation as seen by 3 dimensional reconstructions of micro-computed tomography, radiography, and histopathology. Estrogen supplementation further enhanced the growth of MCF-7 cells in the bone, and increased new bone formation (osteosclerosis). The final objective was to describe methods for isolation, maintenance, and use of human and mouse-derived mesenchymal stem cells (hMSC/mMSC) to model tumor stromal fibroblasts within complex tumor microenvironments in vitro (3D Tumor Growth Assays) and in vivo (mouse transplant and xenograft models). The goal of this objective was to investigate methods to study the role of the tumor stroma in current models of cancer and metastasis. These studies support the role of the tumor microenvironment as an active partner in the pathogenesis of breast cancer metastasis. Additionally, we demonstrated that concomitant changes in the tumor stroma can affect the growth and metastasis of tumor cells, and identify opportunities for therapeutic intervention. Finally, this work helps to better characterize and identify models which are valuable for preclinical studies of breast cancer metastasis.
Advisors/Committee Members: Rosol, Thomas.
Subjects: Biology; Health Sciences; Medicine; Oncology
Keywords: breast cancer, metastasis, models, fibroblasts, Ets2, interleukin-6, estrogen, tumor microenvironment
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17.
Wolk, Kendra E.
Influenza A Virus Inhibits Alveolar Fluid Clearance in BALB/c Mice.
Degree: MS, Comparative and Veterinary Medicine, 2012, Ohio State University
► Influenza A virus causes pulmonary edema, pneumonia, and acute lung injury. Pulmonary…
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▼ Influenza A virus causes pulmonary edema, pneumonia, and acute lung injury. Pulmonary infections can impair alveolar fluid clearance via nucleotide-mediated mechanisms, contributing to these adverse effects. These studies investigate the effects of influenza A virus infection on alveolar fluid clearance, and identify intercellular signaling mechanisms underlying influenza mediated inhibition of alveolar fluid clearance. We established a reliable model of infection by instilling influenza A/WSN/33 intra-nasally in BALB/c mice (10,000 or 2,500 focus-forming units per mouse). Alveolar fluid clearance was calculated in anesthetized mice by instilling 5% bovine serum albumin into the dependent lung and measuring the resultant lung fluid protein concentration following ventilation for 30 minutes. Specific agonists and inhibitors were incorporated into the instillate to elucidate the involvement of specific signaling mechanisms. These compounds included inhibitors of the epithelial sodium channels, inhibitors of the cystic fibrosis transmembrane conductance regulators, inhibitors of the P2Y purinergic receptors, inhibitors of de novo pyrimidine synthesis, and β-agonists. Infection with high-dose influenza A virus resulted in a steady decline in arterial oxygen saturation and increased lung water content. Alveolar fluid clearance was significantly inhibited starting 1 hour after infection, and remained suppressed through 6 days post-infection. Alveolar fluid clearance inhibition at early time points (1–4 hours after infection) did not require viral replication, whereas inhibition later in infection was replication-dependent. Low-dose influenza A virus infection impaired alveolar fluid clearance for 10 days, but induced only mild hypoxemia. High-dose influenza A virus infection increased bronchoalveolar lavage fluid ATP and UTP levels. Impaired alveolar fluid clearance 2 days post-infection resulted primarily from reduced amiloride-sensitive alveolar fluid clearance (epithelial sodium channel inhibition). However, an additional component of alveolar fluid clearance impairment was due to activation of type A1 adenosine receptors and stimulation of cystic fibrosis transmembrane conductance regulator-mediated anion secretion. Finally, influenza a virus-mediated inhibition of alveolar fluid clearance 2 days post-infection was reversible via addition of either β-agonists or the de novo pyrimidine synthesis inhibitor A77-1726 to the instillate. These studies suggest that alveolar fluid clearance inhibition may be an important feature of early influenza A virus infection, and that nucleotides in the lung play a key role as mediators of this process. Pharmacological blockade of these effects may provide a novel method to reduce the severity of pulmonary edema and hypoxemia associated with influenza pneumonia.
Advisors/Committee Members: Davis, Ian.
Subjects: Medicine; Virology
Keywords: Influenza; alveolar fluid clearance; pneumonia; orthomyxovirus; pulmonary edema; ion transport; adenosine
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18.
Zaldivar-Lopez, Sara.
HEMOGLOBIN SYNTHESIS, FUNCTION AND METABOLISM IN GREYHOUNDS.
Degree: PhD, Comparative and Veterinary Medicine, 2012, Ohio State University
► The Greyhounds’ history as racing sighthounds has resulted in a unique physiology…
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▼ The Greyhounds’ history as racing sighthounds has resulted in a unique physiology that distinguishes them from other dog breeds. Results of routine clinical pathology tests in retired racing Greyhounds (RRGs) frequently lie outside of the reference ranges for dogs, and many of these peculiarities have also been described in other sighthounds. Iron is necessary in the body for RBC production, but its metabolism has to be tightly regulated because when free and in excess iron is toxic. Most functional iron is found as hemoglobin (Hb). We have investigated iron metabolism in Greyhounds compared to other dog breeds, finding that UIBC and TIBC are lower and %SAT is higher. We also evaluated iron status in current blood donor dogs and effects over time: iron and %SAT are higher and UIBC is lower in blood donors when compared to controls, and over time iron and %SAT decrease and UIBC/TIBC increase. Our canine population donation intensity and iron status is comparable to human “superdonors”. Identification of the biology underlying this has important implications for human medicine. The Hb molecule is formed by symmetric pairing of alpha and beta globin chains into a structural and functional unit with an iron ion (oxygen-binding site). Due to the high prevalence of hemoglobinopathies in people, the alpha- and beta-globin genes of humans, mice, and chickens, are well characterized. However, despite the increasing importance of dog as models for human diseases, almost nothing is known about dog Hb genetics, and it is reported they only have one beta globin gene, and that they lack fetal Hb. Hb in Greyhounds has higher oxygen affinity, better oxygen carrying properties and same 2,3-DPG content than other dog breeds. We have defined the genetics of canine alpha- and beta-globin genes, and discovered several SNPs and haplotypes that could explain the Greyhound-specific Hb properties. Galgos Españoles (Spanish Greyhounds) have also better oxygenation parameters and higher Hb affinity than mixed breed dogs. During intravascular hemolysis, Hb is released into the bloodstream and can cause oxidative damage to the tissues (e.g. hypertension, kidney damage, thrombosis). Haptoglobin (Hp) binds to the free Hb and removes it from circulation. Former racing Greyhounds have low Hp concentration that could partially account for the low α- globulin concentrations in the breed. We have investigated the HP gene in Greyhounds, finding that the gene is expressed in this breed, and it does not have sequence variations that can explain this anhaptoglobinemia. We also found that Galgos Españoles have similar Hp concentrations to non-Greyhound dogs. Overall, the purpose of this thesis is to be a comprehensive investigation of hemoglobin physiology and genetic characterization in Greyhounds, including its synthesis (i.e. iron) and degradation (i.e. haptoglobin). In order to obtain a better understanding, we also studied Hb and Hp in Galgos Españoles because, although registered as a different breed, Galgos Españoles are phenotypically indistinguishable from Greyhounds, with the difference of not being under the strong selection of the racing industry.
Advisors/Committee Members: Couto, C. Guillermo.
Subjects: Health Sciences
Keywords: iron, haptoglobin, exercise physiology, globin, dog
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