Browsing by Subject "Large or Food Animal and Equine Medicine"
Now showing 1 - 3 of 3
- Results Per Page
- Sort Options
Item An Analytical Study of the Perceptions, Prevention Strategies, Treatment and Economic Impact of Equine West Nile Virus(2004-06-01) Galvan, Robert; Lurie, Sue; Singh, Karan; Gonzalez, AdelaGalvan, Robert, M.P.H., M.S. An Analytical Study of the Perceptions, Prevention Strategies, Treatment and Economic Impact of Equine West Nile Virus. Doctor of Public Health, Social and Behavioral Sciences, June 2004, 109 pp., 16 Tables, 15 Figures, 47 Titles. Since the introduction of the West Nile Virus (WNV) in the United State in 1999, WNV has been the cause of disease and deaths in humans, wild birds, zoo birds, and horses. In 2002, more than 15,000 equines in 40 states were diagnosed with illness associated with WNV. Approximately one third of those horses died or were euthanized (Campbell et al, 2002). Horses are infected with the WNV more often than humans or any other mammal. It is becoming on e of the fastest growing health threats to horses nationwide. Texas responded to the discovery of WNV by expanding their surveillance systems in the eastern counties of the state (Texas Department of Health, 2003). Positive reports for WNV were announced in 2002, which prompted an increase in public education and equine vaccination recommendations. Although much has been reported on the economic impact WNV has on human health and hospital care facilities, documentation is lacking on these issues in the equine population. Understanding the biology, epidemiology, economic impact, and how WNV affects the equine industry are important aspects to public health programs and prevention activities. The objectives of this study are to: (1) examine WNV cases in the equine population in Texas in order to better understand the distribution of clinical disease, signs, treatments and outcomes; (2) to provide information regarding the perceptions, knowledge, concerns, and treatment of the WNV by Texas veterinarians; and (3) to determine the economic impact of the WNV on the equine population in the state. A 14 question survey was mailed to licensed veterinarians in Texas in an effort to gather information about their perceptions and beliefs of the WNV, recommended treatment preferences, and the estimated cost of treatment. Outcomes included case fatality rate, descriptive data, veterinarians’ knowledge of WNV, veterinarians’ beliefs/perceptions of WNV, and the economic impact of WNV. Descriptive analyses were performed by using SPSS version 11. The methods used for analysis of WNV data were primarily simple descriptive statistics including summations and frequencies. A cross-tabulation was performed between the results of Questions 1, 2, and 3 and a variable created to approximate the number of veterinarians that actually treated cases of WNV (treat). A cross-tabulation and Chi-square analysis was performed between the treatment variables (treat) and derived variables of Questions 1, 2, and 3 to examine differing beliefs and knowledge between veterinarians who had treated WNV and those who had not. Seven hundred of 4,177 surveys returned yielded a response rate of 16.8 percent. Among the veterinarians, 73.4% (514/691) believed that they are receiving or received enough training and/or education concerning WNV. The vaccination regimen is believed to be effective and reliable by 56.1% (393/691) of the respondents. There were 1,256 cases of equine WNV reported confirmed via laboratory testing. There were also 766 cases reported that were not confirmed via laboratory testing. Among the 2,022 diagnosed cases, 257 were vaccinated against WNV prior to illness; and, 159 cases were vaccinated after signs of illness. A total of 441 horses died as either a direct cause of the disease or by owner or veterinarian elected euthanasia. The most common criteria used to decide euthanasia in these horses was prolonged recumbency as reported by 44.2% (87/197) or the veterinarians. Fifty-two percent (233/488) of the veterinarians did not recommend prevention strategies to equine owners. The cost of vaccination regimen was reported by 63% (269/434) of the veterinarians to be $25 or less. The results of the survey suggest that there could be a need for WVN education among veterinarians in areas of prevention, control, and treatment. Future studies should be conducted to examine owner perceptions, knowledge and beliefs of WNV vaccinations and prevention strategies. Values for lost horses were not solicited in the survey, thus, a total economic impact could not be completely estimated. However, a formula to approximate the aggregate economic impact of the WNV on the Texas equine industry was employed.Item Characterization of the Myo-inositol Efflux Pathway in Cultured Bovine Lens Epithelial Cells(1997-12-01) Reeves, Rustin E.; Victoria Rudick; Robert Easom; Thomas YorioReeves, Rustin E., Characterization of the Myo-inositol Efflux Pathway in Cultured Bovine Lens Epithelial Cells. Doctor of Philosophy (Biomedical Sciences), December, 1997, 173 pp., 1 table, 28 figures, bibliography, 94 titles. The basic cellular requirement of volume regulation utilizes many different channel and transport pathways working on concord to maintain a constant cell volume. Among these are distinct pathways spontaneously activated by changes in cell volume that modulate the gain or loss of certain organic osmolytes, such as myo-inositol (MI). The major goal of this dissertation is to characterize and identify the mechanism involved in the MI effux pathway and explore its relationship with intracellular polyol accumulation in cultured bovine lens epithelial cells (BLECs). Hypertonic exposure of BLECs causes an increase in MI uptake and aldose reductase enzymatic activity, two events which ultimately influence osmolyte efflux. A biphasic efflux pathway induced by rapid cell swelling (hypotonic-induction) was demonstrated in BLECS switched from hypertonice to physiologic medium. Also, intracellular polyol accumulation from galactose exposure resulted in enhanced activation of the MI efflux pathway (polyol-induction). Chloride channel inhibitors effectively blocked MI efflux suggesting a relationship between anion (chloride) movement and intracellular MI loss from cell to medium. Expression of a chloride channel regulatory protein, pICln, was demonstrated by Northern blot analysis in cultured BLECs. Hypertonic exposure upregulates the expression of pICln mRNA while hypotonicity downregulates expression. The volume-sensitivity for transcription of PICln mRNA in BLECs lends strong support for its role in both anion and osmolyte loss associated with the MI efflux pathway. The MI efflux pathway functions as a “relief value” in cell volume regulation by providing a conduit to alleviate intracellular osmotic stress. The mechanism which evolved to function under normal cellular circumstances in relief of excessive accumulation of intracellular osmolytes (i.e. polyols), may, by design, inadvertently promote the loss of essential intracellular volume and nonvolume regulatory organic solutes. Ironically, under certain pathological conditions, this mechanism, designed to protect the cell from intracellular osmotic stress, may instead be detrimental to the cell by promoting the excessive loss of osmolytes essential for normal cell function.Item The Effects of Elevated Glucose Upon Na+/K+-ATPase in Bovine Retinal Pigment Epithelial Cells(1994-12-01) Crider, Julie Y.; Thomas Yorio; John Lane; Edward OrrCrider, Julie Y., The Effects of Elevated Glucose Upon Na+/K+-ATPase in Bovine Retinal Pigment Epithelial Cells. Doctor of Philosophy (Biomedical Sciences, Pharmacology), December, 1994, 154 pp., 14 tables, 31 illustrations, bibliography, 288 titles. Bovine retinal pigment epithelial (RPE) cells were cultured under 1, 4.5 and 10 g/l glucose conditions in order to characterize the effects of hyperglycemia upon Na+/K+-ATPase. Functional activity of Na+/K+-ATPase was measured as ouabain-sensitive Rb+ uptake. 3H ouabain was used to assess binding characteristics of Na+/K+-ATPase. The major contributors to rubidium (mRb+) uptake activity were the ouabain-sensitive Na+/K+-ATpase and a bumetanide-sensitive NA+/K+/Cl- cotransporter. Dose response curves for ouabain and bumetanide produced IC50 values for 86Rb+ uptake of 60-100 nM and 120 nM, respectively. At elevated glucose concentrations, the aldose reductase inhibitor (ARI) AL-1576 stimulated 86Rb+ uptake upon chronic treatment. A sensitive new nonradioactive Rb+ uptake assay was developed which utilized suppressed conductivity detection and provided several advantages over the radioactive method. The average ouabain IC50 value was confirmed to be 100nM and was not significantly affected by elevated glucose concentrations. The bumetanide sensitive component was responsible for approximately 30% of Rb+ uptake at all glucose concentrations. Potassium efflux out of the cells was observed that was sensitive to the Na+/K+/Cl- cotransport inhibitor bumetanide. Elevated glucose appeared to increase Rb+ transport through potassium channels was also reduced Rb+ uptake indicating a decrease in Na+/K+-ATPase activity. Bovine RPE cells exposed to both high glucose and AL-1576 for one month showed mild stimulation of Rb+ uptake compared to the activity in high glucose alone. Ouabain and strophanthidin inhibition of 3H ouabain binding, in bovine RPE cells, appeared to be unaffected by hyperglycemia. The average IC50 values for these compounds were 5.02 x 10^-8 M, respectively. The results of this study indicate that Na+/K+-ATPase activity in bovine RPE is decreased by hyperglycemic state, and can be stimulated by treatment with an aldose reductase inhibitor administered from the onset of the hyperglycemic insult.