Biomedical subjects
Publications and source records attributed to D C Knottenbelt.
Several imaging techniques were used to diagnose hypoplasia of the soft palate in a horse. The absence of the caudal soft palate, hypertrophied lymphoid tissue and the formation of a pseudouvula were observed endoscopically. Plain and contrast radiography were used to demonstrate a soft palate remnant and to identify structures rostral to the epiglottis. Retrograde endoscopy of the pharynx via a tracheotomy incision is described.
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In preliminary investigation of the pharmacokinetics of aspirin in dogs it became apparent that the drug was well absorbed following oral ingestion with food. Multiple dosing appeared to lead to a substantial increase in half-life; a twice daily dosage regimen would, therefore, be adequate for maintenance of therapeutic levels in dogs. The marked variation in pharmacokinetic parameters observed suggested that therapeutic drug monitoring would be benefit in the control of canine inflammatory conditions using aspirin. Therapeutic monitoring of dogs (n = 20) showed that clinical improvement paralleled plasma salicylate concentrations and the therapeutic concentrations so determined were within the range considered therapeutic in humans. No overt gastric irritation was noted in this study over a period of a year which suggests that aspirin can be successfully used to treat canine inflammatory disorders, routine monitoring of plasma salicylate being recommended to ensure therapeutic success.
Seventeen cases of vaginal rupture with herniation of abdominal organs were examined. The injury consisted of a dorsal tear in the vagina and, most frequently, evisceration of the bowel. The tear was accompanied by extensive vaginal bleeding. Serum calcium concentrations were low in the affected cases and the concentrations of beta-hydroxybutyric acid and urea were high. The average age of the affected ewes was four years (range 3 to 6). They were generally in poor condition and carrying more than one fetus (2.7 lambs per ewe) although younger ewes and ewes in good condition were also affected. No primiparous ewes were affected. Ten of the 17 ewes were found dead and six were humanely destroyed; in one, the injury was repaired surgically but the ewe died 48 hours later.
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One month after falling heavily a four-year-old horse developed acute colic while being exercised. A tentative diagnosis of diaphragmatic hernia was reached on the basis of the clinical findings and confirmed at laparotomy. The defect was repaired and the horse made an uneventful recovery.
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Wound healing in equidae is delayed and more complicated than in other species. These complications arise from a condition known as exuberant granulation tissue formation. The lower limb of the horse is frequently slower to heal than other parts of the body and has a particular tendency to produce excess (exuberant) granulation tissue. Sarcoids are tumor-like lesions of the skin which often appear at the site of wounds. This study compared the growth characteristics of the sarcoid and granulation tissue-derived cells with normal dermal fibroblasts grown from primary cell cultures. All three cell types had distinct morphologic differences. Growth rate studies showed that the sarcoid and granulation tissue-derived cells grew at a slower rate than the normal cells. The addition of the growth factors epidermal growth factor, acidic fibroblast growth factor, and basic fibroblast growth factor selectively stimulated the replication of normal and sarcoid-derived cells but inhibited the growth of granulation tissue-derived cells. In contrast, transforming growth factor-beta was not preferentially inhibitory for the granulation tissue-derived cells. The addition of growth factors to the medium also produced distinct alterations in the morphology of the cells.
This report describes the history, clinical, electrocardiographic and echocardiographic findings, treatment, outcome and post-mortem findings in seven horses with aorto-cardiac fistula. Affected horses included 5 stallions, one gelding and one mare; 2 each of the Thoroughbred, Arabian and Standardbred breeds and one Thoroughbred-cross with a mean +/- s.d. age of 12 +/- 4 years, range 6-18 years. The presenting signs were acute distress (four horses), exercise intolerance (two horses) and the lesion was detected during a routine examination in one horse. Five horses had monomorphic ventricular tachycardia on admission and one other had a history of this arrhythmia. Five horses had a characteristic continuous murmur loudest in the right fourth intercostal space. Echocardiography (six horses) and/or post-mortem examination (four horses) revealed the horses had aorto-cardiac fistulas arising from the right aortic sinus in all five horses in which the site was recorded. Two horses had ruptured aneurysmal dilatations of the aortic wall at this site. Fistulas extended into the right ventricle in four horses; the right atrium in two horses, the left ventricle in one horse, and five horses had dissecting tracts in the septal myocardium. Horses survived for periods ranging from 24 h to 4 years. Aorto-cardiac fistula should be considered in the differential diagnosis for horses presenting with acute distress, bounding arterial pulse, a right-sided continuous murmur and/or monomorphic ventricular tachycardia, particularly in middle-aged or older stallions. Echocardiography is the technique of choice for confirming the diagnosis and demonstrating accompanying cardiac changes.