Spelling suggestions: "subject:"veterinary cience"" "subject:"veterinary cscience""
691 |
The role of substance p in bovine pneumonia caused by Mannheimia haemolyticaRagsdale, John January 1900 (has links)
Doctor of Philosophy / Department of Diagnostic Medicine/Pathobiology / Derek A. Mosier / The bovine respiratory disease complex (BRDC) is a major concern for cattle producers in the United States and worldwide. One of the most costly and deadly components of BRDC is bovine pneumonic pasteurellosis (BPP) caused by Mannheimia haemolytica. The initial pulmonary inflammation associated with BPP is a characteristic serofibrinous exudation into the lung, which is believed to be induced by M. haemolytica virulence factors such as lipopolysaccharide (LPS) and leukotoxin (LKT) and host cytokines and chemokines such as tumor necrosis factor – α, interleukin – 1β, and interleukin – 8. However, these pulmonary changes often occur before virulence factors or cytokines are substantial components of the pulmonary microenvironment. Other proinflammatory molecules such as substance P (SP) may be involved in the pathogenesis of the peracute serofibrinous exudation of BPP. SP is an 11 amino acid long neuropeptide that is a neurotransmitter of pain that can be released from sensory nerves into tissues to cause neurogenic inflammation. Neurogenic inflammation is characterized by serofibrinous exudation and leukocyte activation. SP-like immunoreactivity was present in the airways, alveolar septa, macrophages, endothelium, and peribronchial nerves in both pneumonic and normal bovine lung; however, SP-like immunoreactivity was increased in pneumonic compared to normal bovine lung due to increased immunoreactivity in macrophages. SP and the combination of SP with histamine and LPS increased the permeability of a calf pulmonary arterial endothelial cell line to Evans blue dye labeled albumin by 12.34%, 13.57%, and 22.03%, respectively compared to a cell control. Similarly, SP and the combination of SP and histamine increased the monolayer permeability of a bovine adrenal gland capillary endothelium by 8.27% and 16.69% compared to a cell control. The increase in permeability was due to endothelial cell shape change and the formation of intercellular gaps rather than cell death. However, SP does not increase the surface expression of the β2 integrin CD18 (the M. haemolytica LKT receptor) on bovine neutrophils nor does it increase LKT-induced leukocytotoxicity of bovine peripheral blood leukocytes. These findings indicate that SP may be a contributor to BPP in association with other cytokines. Read more
|
692 |
Epidemiology, diagnosis, and prevention of bovine respiratory disease complexHanzlicek, Gregg Alan January 1900 (has links)
Doctor of Philosophy / Department of Diagnostic Medicine/Pathobiology / David G. Renter / Bradley J. White / The objective of my research was to generate novel information concerning the epidemiology, diagnosis and prevention of bovine respiratory disease complex (BRDC), a common pre-weaning and post-weaning beef calf disease. To reach my objective, I conducted three prospective field trials within post-weaned calf populations, and one retrospective study of pre-weaned calves utilizing survey data.
I evaluated differences in behavior, health and performance in calves receiving multiple component health programs. Calves in a minimally invasive program, which included primarily non-injectable products, displayed less aversion to initial product administration but experienced higher BRDC morbidity (P = 0.02) and poorer performance (P = 0.04) compared to calves in a more invasive (all injectable products) program.
Secondly, in a study of Mannheimia haemolytica inoculated calves, I found that no parameter included in physical examinations, or common blood component evaluations could discern health from disease. However, disease recognition was aided by the measurement of the number of steps taken by a calf in a 24 hour period. None of the parameters that were evaluated predicted the severity of lung pathology.
Thirdly, I conducted a study in post-weaned feeder calves that determined prevalence estimates for Mollicutes in general, and Mycoplasma bovis specifically, and their respective associations with health and performance. Nasal Mollicutes prevalence was high on arrival, and differences in calf performance were associated with (P < 0.01) nasal prevalence. More than half of the calves seroconverted to M. bovis; calves not seroconverting gained more weight (0.49 kg/head/day) during the study than those calves that did seroconvert (0.35 kg/head/day).
Finally, I conducted a retrospective analysis of national U. S. cow-calf survey data to identify herd level management practices associated with pre-weaned calf BRDC. I found feeding antibiotics to pre-weaned calves, importing cattle, the number of outside visitors, economic purpose of the cow-calf operation, and breeding management of the herd were associated with herd-level pre-weaning BRDC rates.
My research projects generated unique information concerning the epidemiology of important pathogens, differences among preventive health programs, objective BRDC diagnostic parameters, and pre-weaning BRDC risk factors. These research studies reinforce the complexity of BRDC and demonstrate the pathogen, animal and management factors affecting BRDC risk in pre- and post-weaned beef calves. Read more
|
693 |
The use of thermography in clinical Thoracolumbar disease in DachshundsSargent, Gerald R. January 1900 (has links)
Master of Science / Department of Clinical Sciences / James K. Roush / Objective – To evaluate the value of thermography in a clinical setting for dogs with thoracolumbar disease.
Animal Population – Thirteen client-owned short-haired Dachshunds presented to Kansas State University Veterinary Medical Teaching Hospital for paraparesis/paraplegia and diagnosed with thoracolumbar disease via myelogram/CT and confirmed during surgical decompression.
Procedures - Thermal images were obtained with a hand-held infrared camera with a focal plane array uncooled microbolometer. Images were obtained after physical exam and client consultation and prior to any pre-anesthetic medications, approximately 30+ minutes after entering the hospital. Additional images were obtained in the same manner at 24 hour intervals following surgery until discharge. Six regions of interest (ROI) were identified and recorded. The ROIs identified were right and left thoracic, lumbar and pelvic regions. From each of these regions average temperatures were taken.
Results - Temperatures in the pelvic region were significantly cooler (p< 0.001) over all days as compared to the thoracic and lumbar regions and to the overall mean temperature. The lumbar region temperature was significantly greater on day 0 as compared to thoracic and pelvic regions but was not significantly different on any of the following days. The thoracic temperatures were significantly greater than the lumbar and pelvic regions on day 2 but there was no significant difference on any of the preceding or following days. There was no significant difference between left and right on any of the days. There was a correlation of the pelvic region temperatures on day 3 in relation to the presenting neurological grade.
Conclusion - Although there were varied heat patterns detected in dachshunds with IVDD, these patterns did not correlate with neurological grade, lesion site or lateralization of the lesion. Although there was a correlation between neurological grades and the pelvic region temperatures on day 3, this time period is unlikely to provide clinical utility.
Clinical Relevance - The results of this study suggest that thermography is not a useful tool for the diagnosis or prognosis of thoracolumbar disease in dogs in a clinical setting. Read more
|
694 |
The impact of oxytetracycline dosing on bacterial populations and transfer of resistance elements in vitro and in vivoLubbers, Brian Vincent January 1900 (has links)
Doctor of Philosophy / Department of Diagnostic Medicine/Pathobiology / Michael D. Apley / The discovery of modern antimicrobials in the early 20th century revolutionized treatment of infectious diseases. Less than 100 years later, antimicrobial resistance has become a global threat to public health. With the rise of antimicrobial resistance, the question that remains to be answered is: Can dosing regimens provide maximal clinical efficacy, yet minimize the development of antimicrobial resistance?
A pharmacokinetic / pharmacodynamic approach was utilized to investigate oxytetracycline regimens that would impart efficacy while minimizing the potential for resistance development due to plasmid transfer. An in vitro pharmacodynamic model was used to quantify the response of a Pasteurella multocida isolate to two oxytetracycline dosing regimens. The PK/PD index most closely related to efficacy was the Cmax:MIC.
The in vitro pharmacodynamic model was then used to investigate the effects of antimicrobial exposure on plasmid transfer. A mixed population of oxytetracycline-susceptible and resistant bacteria was exposed to two dosing regimens and plasmid transfer was quantified. When oxytetracycline concentrations exceeded the MIC of the recipient, development of resistance was suppressed.
The same donor and recipient bacteria were used in an in situ swine model to validate the in vitro findings. Following surgical implantation of porous membrane straws containing the mixed bacterial population, animal subjects in the treatment groups received one of two oxytetracycline treatments. Oxytetracycline concentrations in the plasma and interstitial fluid were quantified. Plasmid transfer within the implant membranes was quantified and correlated
to pharmacokinetic measures in the animal. Plasmid transfer rates in the implant membranes did not correlate to the investigated pharmacokinetic parameters.
The study methodologies in this dissertation should serve as a foundation for future studies in antimicrobial pharmacokinetic/pharmacodynamic research. The results presented here show that the bacterial response to oxytetracycline can be optimized in a concentration dependent manner and that antimicrobial resistance development through plasmid transfer can be suppressed in vitro when oxytetracycline concentrations exceed the MIC of the recipient bacteria. These results suggest that a proper balance between clinical efficacy and minimizing antimicrobial resistance can be achieved for oxytetracycline through appropriate dosing regimens and drug formulations. Read more
|
695 |
Addressing curriculum deficiencies in veterinary public health: a comparison of other health professions’ experiencesAkers, Jennifer January 1900 (has links)
Master of Public Health / Department of Diagnostic Medicine/Pathobiology / Justin J. Kastner / David G. Renter / The history of veterinary medicine is intimately intertwined with duties to public health. This has remained true over centuries, and is becoming even more important with recent significant threats to public health. Despite this, the veterinary profession is failing to meet increasing needs for veterinarians trained in population medicine and public health, nationally and internationally.
Current accreditation requirements for veterinary schools and colleges are vague with regard to public health education, leaving each college or school of veterinary medicine to implement its own perception of veterinary public health education. Is the public health education in veterinary curricula adequate among U.S. veterinary colleges and schools? Our inventory of the veterinary curricula in the 28 U.S. veterinary schools and colleges revealed inadequacies in veterinary public health education delivery. We found that most colleges and schools are lacking in the major veterinary public health subjects as recommended by the American College of Veterinary Preventive Medicine and the World Health Organization.
The issue of inadequacies, even deficiencies, within health professional curricula is not unique to the veterinary profession. What have other health professions proposed to correct their own perceived deficiencies within their educational curricula? We identified deficiencies and proposed solutions from three health professions and discussed their solutions as potential approaches to remedy the inconsistency in public health delivery in veterinary curricula. The dental profession addressed lack of faculty effectiveness with faculty development programs. The medical profession identified an outdated and irrelevant pre-medical curriculum and is currently considering reforming it. The
chiropractic profession identified a lack of public health education in its curriculum and organized a standardized public health course.
Health professions are similar in content of curricula and length of professional program. In addition, the health professions have similar pre-requisites. They also share similar challenges: faculty shortages, high student debt loads, and rising educational costs. Because of these similarities, solutions to perceived curricular deficiencies proposed in one health profession can be used to address deficiencies in other health professions. Therefore, the dental, medical, and chiropractic professions have proposed solutions that should be considered in addressing the veterinary profession's curricular deficiency of inadequacy in public health education. Read more
|
696 |
Validation and implementation of a remote three-dimensional accelerometer monitoring system for evaluating behavior patterns in cattleRobért, Bradley Duane January 1900 (has links)
Master of Science / Department of Clinical Sciences / Robert L. Larson / Bradley J. White / We performed research that investigated the ability of three dimensional accelerometers to classify cattle behavior and also describe the circadian patterns within that behavior. The first of three studies (validation study) tested a decision tree classification system and its ability to describe behaviors of lying, standing, and walking. Classification accuracies for lying, standing, and walking behaviors were 99.2%, 98.0%, and 67.8% respectively, with walking behavior having significantly lower accuracy (P<0.01). This study also tested the accuracy of classifying the above behaviors using different device reporting intervals, or epochs. Reporting intervals of 3, 5, and 10 seconds (s) were evaluated in their ability to describe cattle behaviors of lying, standing, and walking. Classification accuracies for the 3s, 5s, and 10s reporting interval were 98.1%, 97.7%, and 85.4% respectively, with no difference in classification accuracy of the 3s and 5s epochs (P=0.73) while the 10s epoch exhibited significantly lower overall accuracy (P<0.01). This validated accelerometer monitoring system was then implemented in two studies (Winter 2007 and Spring 2008) where the devices were used to describe behavior patterns of beef calves in a drylot production setting. Lying behavior of the cattle was analyzed and found to be significantly associated (P<0.001) with hour of the day. Calves in these studies spent most (> 55%) of the nighttime hours (2000 to 0400) involved in lying behavior and spent the least percentage of time lying (<30%) during periods of time where feed was presented at the bunk (0700 and 1700). Mean lying time was also associated with trial day (P<0.01) and most trial days (67.5%) calves spending between 45% and 55% of time lying. Variation of lying behavior was found between individuals (range 29% to 66%); however, consistency in lying behavior was found within individual calves across study periods. The accelerometer monitoring system studies presented here provide evidence these devices have utility in recording behaviors (lying, standing, and walking) of individual beef calves raised in typical production settings. Read more
|
697 |
Étude des effets secondaires associés à un traitement prolongé de fluticasone inhalée chez les chevaux atteints de souffle (asthme équin)Muñoz Diaz, Trohadio Tomás 02 1900 (has links)
Le souffle équin est une maladie inflammatoire chronique des petites voies
respiratoires, très fréquente chez les chevaux gardés à l’intérieur avec de la
paille et du foin moisi et poussiéreux. Les signes cliniques peuvent être
prévenus par le contrôle de l’environnement et soulagés par l’administration
de corticostéroïdes systémiques et inhalés. L’objectif de cette étude était de
déceler les effets secondaires présents sur des chevaux atteints de souffle
traités à la fluticasone (Flovent 250 μg HFA®, 2000 μg BID, pendant six
mois, et puis 2000 μg SID, pendant six autres mois) par le cortisol sérique et
la présence d’ulcères gastriques. Cinq chevaux exempts de maladie
respiratoire et onze chevaux atteints du souffle ont été gardés à l’intérieur
d’une écurie avec du foin moisi et de la paille dans le but de provoquer la
maladie chez le groupe atteints du souffle. Une fois les chevaux atteints de
souffle devenus symptomatique, ils ont été divisés en deux groupes : un
premier groupe traité avec de la fluticasone, nourri avec du foin et gardé sur
une litière de paille, et un deuxième groupe non traité nourrie avec de la
moulée et gardé sur une litière de ripe, pendant six mois. Par la suite, les
deux groupes ont été mis au pâturage. Le cortisol a été mesuré par Immunoessai
enzymatique par chimiluminescence (CEIA, Immunolite 1000,
Siemmens®) les 12e et 10e jours avant et les 7e, 28e, 80e, 160e, 200e, 250e,
290e et 320e jours après le début du traitement afin de déterminer le degré
de suppression du cortisol sérique. On a également fait une suivi de la
présence d`ulcères gastriques à l`aide de vidéo endoscopique. La fluticasone
inhalée deux fois par jour cause une diminution du cortisol sérique les 28e,
80e et 160e jours, mais elle n’entraîne pas d’effets sur le score des ulcères
gastriques. Les pellets de luzerne causent quant à elles, une augmentation
du score des ulcères gastrique chez les animaux exempts de maladie
respiratoire. / Recurrent Airways Obstruction (RAO) is a small airways inflammatory
disease, very common in horses stabled in mouldy-dusty hay and straw
environments. The clinical signs are prevented by environmental control,
relieved by systemic and inhaled corticosteroids. Our objectives were to
determine whether inhaled corticosteroids cause a suppression of cortisol
levels and gastric ulceration in RAO horses treated with fluticasone 2000μg
(Flovant HFA®) BID for 6 months and 2000μg SID for another 6 months. Five
(5) healthy horses were used as controls and eleven (11) RAO affected
horses were stabled in a moldy-dusty environment to induce disease
exacerbation. Once they were symptomatic, they were divided into two
groups, the treated group was kept on hay/straw and the untreated group
was fed with pellets food and bedded on wood shavings six months.
Afterwards, all horses were pasture for the next 6 months. Serum cortisol
was mesured by Immuno-essai enzymatique par chimiluminescence (CEIA,
Immunolite 1000®, Siemmens) 12, 10 days before and 7, 28, 80, 160, 200,
250, 290, 320 days after treatment initiation, in order to determine cortisol
suppression. Fluticasone administered twice a day reduces blood cortisol
levels after 28, 80 and 160 days, but did not cause any change in gastric
ulcers. However, pellets slightly increased gastric ulcer scores in healthy
horses. Read more
|
698 |
Etude d'un anticoagulant oral (le rivaroxaban) sur les paramètres hémostatiques de chiens en santéConversy, Bérénice 04 1900 (has links)
Chez le chien, les thromboses représentent une complication majeure de nombreuses conditions qui sont revues dans ce manuscrit. L’arsenal thérapeutique actuel présente certaines limites: des effets anticoagulants variables d’un patient à l’autre, des hémorragies et une administration par voie sous-cutanée pour l’héparine. Le rivaroxaban est un nouvel anticoagulant oral approuvé pour la prévention et le traitement des thromboses chez l’humain. C’est un inhibiteur direct du facteur Xa.
La présente étude a pour objectif d’évaluer les effets hémostatiques du rivaroxaban chez des chiens en santé, en utilisant les tests de coagulation suivants: temps de prothrombine (PT), temps partiel de thromboplastine (aPTT), activité anti-facteur X, génération de thrombine (GT) et thromboélastographie (TEG®).
Tout d’abord, l’effet anticoagulant du rivaroxaban a été évalué in vitro : le plasma citraté pauvre en plaquettes provenant de 20 Beagle en santé a été aliquoté et enrichi avec des solutions de rivaroxaban à des concentrations de 0 à 1000 mg/L d’anticoagulant. Une prolongation concentration-dépendante de tous les tests de coagulation a été notée. Les concentrations de 0.024 et 0.053 mg/L diminuent respectivement de 50% la vitesse de propagation de la GT et la densité optique de l’activité anti-facteur X. Ces derniers tests sont les plus sensibles et précis pour détecter l’effet anticoagulant du rivaroxaban.
Ensuite, 24 Beagle en santé ont été répartis aléatoirement en 3 groupes (n=8). Chaque groupe a reçu par voie orale un placebo, ou 20 mg de rivaroxaban une ou deux fois à 8h d’intervalle. Quinze échantillons sanguins ont été prélevés pour chaque chien sur 30 heures. Pour tous les tests de coagulation excepté la TEG®, une différence significative a été notée dans les résultats entre les groupes traités et le groupe placebo (p<0.0001). La durée de l’effet anticoagulant du rivaroxaban était de 7.9-18.7h dans le groupe traité une fois; et de 17.5-26.8h dans le groupe traité deux fois. Le pic d’action de l’effet anticoagulant était d’environ 2h. Seul le paramètre R de la TEG® était significativement affecté dans les groupes traités.
En conclusion, le rivaroxaban exerce un effet anticoagulant chez le chien à la dose de 2 mg/kg. Une administration biquotidienne semble appropriée pour un effet de 24h. / In dogs, thrombosis is a major complication detected in many conditions. The limits of the current available anticoagulants in veterinary medicine are their variable effects from one patient to another, bleeding complications and subcutaneous injections for heparin administration. Rivaroxaban is a novel oral anticoagulant approved for the prevention and treatment of thrombosis in humans. It is a direct factor Xa inhibitor.
The objectives of the study were to determine the haemostatic effects of rivaroxaban in healthy dogs by evaluating the following coagulation assays: prothrombin time (PT), activated partial thromboplastin time (aPTT), anti-factor X activity, thrombin generation (TG) and thromboelastography (TEG®).
An in vitro study was conducted: citrated platelet poor plasma from 20 healthy Beagles was aliquoted and mixed with rivaroxaban to obtain solutions ranging from 0 to 1000 mg/L of the anticoagulant. Rivaroxaban exerted a concentration-dependent anticoagulant effect. Rivaroxaban solutions at 0.024 and 0.053 mg/L cause 50% inhibition of the propagation of TG and of the optical density of anti-factor X activity respectively. These assays were the most sensitive to detect the anticoagulant effect of rivaroxaban.
Secondly, 24 healthy Beagles were randomly divided in 3 groups (n=8) and received one placebo pill orally, or 20 mg rivaroxaban once or twice at 8h interval. Fifteen citrated blood samples were collected from each dog over 30h. For each coagulation assay except for TEG®, there was a significant difference in assay results between placebo and rivaroxaban groups (p<0.0001). The duration of the rivaroxaban anticoagulant effect was 7.9-18.7h in the group receiving rivaroxaban once, and 17.5-26.8h in the group receiving rivaroxaban twice. The peak of action of rivaroxaban appeared 2h after the dose. Only R parameter of TEG® was significantly affected by rivaroxaban administration.
To conclude, rivaroxaban is an efficient anticoagulant in healthy dogs at 2 mg/kg. A twice daily administration seems appropriate to exert a 24h anticoagulation. Read more
|
699 |
Inward-rectifier chloride currents in Reissner’s membrane epithelial cellsKim, Kyunghee January 1900 (has links)
Master of Science / Department of Anatomy and Physiology / Daniel C. Marcus / Sensory transduction in the cochlea depends on regulated ion secretion and absorption. Results of whole-organ experiments suggested that Reissner’s membrane may play a role in the control of luminal Cl-. We tested for the presence of Cl- transport pathways in isolated mouse Reissner’s membrane using whole-cell patch clamp recordings and gene transcript analyses using RT-PCR. The current-voltage (I-V) relationship in the presence of symmetrical NMDG-Cl was strongly inward-rectifying at negative voltages, with a small outward current at positive voltages. The inward-rectifying component of the I-V curve had several properties similar to those of the ClC-2 Cl- channel. It was stimulated by extracellular acidity and inhibited by extracellular Cd2+, Zn2+, and intracellular ClC-2 antibody. Channel transcripts expressed in Reissner’s membrane include ClC-2, Slc26a7 and ClC-Ka, but not Cftr, ClC-1, ClCa1, ClCa2, ClCa3, ClCa4, Slc26a9, ClC-Kb, Best1, Best2, Best3 or the beta-subunit of ClC-K, barttin. ClC-2 is the only molecularly-identified channel present that is a strong inward rectifier. This thesis incorporates the publication by K.X. Kim and D.C. Marcus, Inward-rectifier chloride currents in Reissner’s membrane epithelial cells. Biochem. Biophys. Res. Commun. 394 (2010) 434-438, with permission of the publisher Elsevier, and is the first report of conductive Cl- transport in epithelial cells of Reissner’s membrane and is consistent with an important role in endolymph anion homeostasis. Read more
|
700 |
Brucellosis in Iraq: epidemiology, present status, and challenges in controlling the diseaseSalih, Harith Mohammed Saleem January 1900 (has links)
Master of Science / Department of Diagnostic Medicine/Pathobiology / Gary A. Anderson / Brucellosis is one of the major endemic zoonotic diseases worldwide, and it has history dating back to 1937 in Iraq when it was first isolated by an Iraqi physician. In order to establish a solution for the continuous devastating impacts of the disease in humans and livestock, the Brucellosis Control Program was established in 1995. The main responsibilities of this program were setting and implementing the appropriate strategies for controlling the disease. After the war in 2003, the United Nation organization for Food and Agriculture (FAO) developed a strategic plan to control the disease. The main goal of the project was to improve productivity in the livestock sector and reduce the prevalence of disease in small ruminants (sheep and goats) to less than 2%, and less than 0.2% in cattle and buffalo. Achieving such goals ultimately would reduce the disease incidence among the human population from more than 27.2 cases/100,000 persons in 2002, to less than 4 cases/100,000 people within 15 years. A serological surveillance was conducted and revealed the apparent prevalence of the disease in sheep and goats, cattle, buffalo, and camels was 6.51%, 1%, 1.48%, and 0.02%, respectively in Iraqi governorates except the three northern governorates of Kurdistan province . Based on surveillance results, a vaccination policy was the only appropriate strategy that could be chosen to control the disease. Four vaccination campaigns were implemented in 2006, 2007, 2008, and 2009, with a total number of vaccinated animals each year at 10099972, 4698482, 753153, and 1833482 head, respectively. The primary satisfactory outcome of the program was the apparent decline in livestock abortions leading to obvious increases in productivity. Regarding the incidence of brucellosis among the human population, the apparent decline in the middle and south of Iraq began with the vaccination phase of the control program in 2006. The results represented a significant decrease in human cases after only four vaccination campaigns of a program that was intended to continue for 15 years. Read more
|
Page generated in 0.1015 seconds