Faculty of Veterinary Science
Department of Companion Animal Clinical Studies
Selected Highlights from Research Findings
Radiological tracheal dimensions of the horse can be used effectively to evaluate upper and lower respiratory tract conditions due to the gradient of pressure changes between these areas. Lateral radiographs of the trachea of 15 clinically-normal sedated thoroughbred horses were made at inspiration and expiration, and magnification corrected mean airway heights measured. The ratio of tracheal height to the thoracic inlet was respectively 0.15 and 0.15. Although not statistically significant, there was a trend towards a higher tracheal height at expiration. No correlation was found between tracheal height and body mass or height at the withers. Radiographic tracheal height evaluation can be made independent of respiratory phase in sedated horses. It is recommended that ratios of tracheal height to an adjacent vertebral body length are more reliable for comparison between horses, and tracheal height measurement should be made at C5, due to a lower standard deviation. If only thoracic radiographs are made, measurements of tracheal height can be made at the thoracic inlet
Contact person: Prof A Carstens.
Acute phase proteins (APP) are ideal biomarkers for inflammation due to their stability, relative ease of assay and the apparent relation between their concentration and the extent of the insult to tissue. C-reactive protein (CRP) is a positive major APP in dogs and can be used as a predictive marker for risk of disease and to monitor the response to treatment. Increased concentrations in certain diseases are associated with poor outcome. This cross-sectional, observational study of 75 dogs naturally infected with Babesia rossi, a cause of virulent canine babesiosis, was designed to examine the relationship between CRP concentration at admission and the magnitude of CRP change 24 hours after admission, with outcome. Dogs were excluded if there was evidence of concurrent inflammatory diseases at the time of admission, infection with subtypes other than B. rossi, concurrent Ehrlichia canis infections or euthanasia for reasons other than poor prognosis. Diagnosis was confirmed by polymerase chain reaction and reverse line blot. CRP concentrations were determined by an automated human CRP Turbidometric Immunoassay (TIA) on serum samples collected by jugular venipuncture on admission, prior to any therapy, and thereafter daily until discharge or death. The researcher found that there was no significant difference in mean CRP concentration between survivors and non-survivors at admission. Using the exact logistic regression, adjusting for age and sex, there was no association with outcome. Multiple regression analysis failed to show a significant relationship between admission CRP concentration and the number of days of hospitalisation in the survivors, adjusting for age and sex (p = 0.65). Similarly, no significance was found in the relationship between the magnitude of change in CRP concentration 24 hours after admission and the number of days of hospitalisation in survivors, (p = 0.34). Using an admission CRP concentration cut-off of 60 mg/l, survival proportions between the two groups were no different (p = 0.34). When applied to the group of dogs that survived, it was not associated with length of hospitalisation (p = 0.25). The researcher concluded that CRP concentration, as a measure of the acute phase response, is not associated with outcome in canine babesiosis, and inflammation is unlikely to be the only cause of severity of disease. Other causes, including individual susceptibility, parasite phenotype and tissue hypoxia, are speculated to play a more important role
Contact person: Dr LS Koster.
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