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  • Author or Editor: Kent A. Gossett x
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SUMMARY

Nineteen purebred Beagles of various ages (4, 5, 13, and 47 weeks) were inoculated with North American Trypanosoma cruzi isolates obtained from an opossum (Tc-O), an armadillo (Tc-A), or a dog (Tc-D). Dogs were grouped on the basis of clinical outcome of infection. During the acute stage of disease, dogs of group 1 (n = 7 inoculated with Tc-O or Tc-A) died or were euthanatized because of the severity of disease. Dogs of group 2 (n = 5 inoculated with Tc-O or Tc-A) developed acute disease, but survived to develop chronic disease. Dogs of group 3 (n = 7 Tc-Dinoculated dogs) developed neither acute nor chronic disease. Dogs of group 4 (n = 4—2 dogs 13 weeks old and 2 dogs 47 weeks old) served as noninoculated controls.

Clinical signs associated with severe acute myocarditis developed in dogs of groups 1 and 2 between postinoculation day (pid) 15 and 28. Generalized lymphadenopathy and lymphocytosis were observed in all dogs of groups 1, 2, and 3 between pid 14 and 17. Serum alanine transaminase and aspartate transaminase activities and urea nitrogen concentration were high, and glucose concentration was low prior to death of dogs in group 1. Serum activities of isoenzymes of creatine kinase were significantly (P < 0.05) high in only 1 dog (group 1), whereas serum lactate dehydrogenase isoenzyme activities were not significantly high in any dog. Parasitemia was detected by examination of thick blood smears as early as pid 3, peaked by pid 17 in most dogs, and was not detected by pid 33 in dogs of groups 1 and 2. Parasitemia was documented by blood culture results in dogs of groups 2 and 3 at various times throughout the study. Dogs infected at an older age generally had lesser degree of parasitemia and higher survival rate than did dogs infected at a younger age.

Dogs of group 2 did not manifest clinical signs of disease for 27 to 120 days prior to onset of chronic disease. Ventricular-based arrhythmias and exercise intolerance developed in all dogs of group 2 at various times by pid 120. Two dogs developed signs of biventricular heart failure.

Free access
in American Journal of Veterinary Research

Summary

To evaluate renal function and obtain reference values for measurements of urinary excretion of various substances, quantitative urinalysis was performed in healthy, growing kittens from 4 to 30 weeks after birth. Endogenous creatinine clearance, 24-hour urine protein excretion, and urine protein-to-creatinine ratio were determined. Additionally, fractional excretion to creatinine clearance was calculated for calcium, inorganic phosphorus, sodium, potassium, and chloride. Mean ± SD endogenous creatinine clearance values (range, 3.80 ± 0.48 to 4.74 ± 0.61 ml/min/kg) were significantly (P < 0.0001) higher in kittens 9 to 19 weeks old, compared with younger (range, 1.39 ± 0.85 to 3.59 ± 0.86 ml/min/kg) and older kittens (range, 2.69 ± 0.40 to 3.46 ± 0.37 ml/min/kg). Mean values for all kittens for 24-hour urine protein excretion (range, 2.54 ± 1.81 mg/kg at 4 weeks to 11.39 ± 7.61 mg/kg at 14 weeks) and for urine protein-to-creatinine ratio (range, 0.14 ± 0.03 to 0.34 ± 0.18) varied from week to week of age. The urine protein-to-creatinine ratio in kittens > 9 weeks old correlated well (R2 = 0.861) with 24-hour urine protein excretion. Urinary fractional excretion of calcium, inorganic phosphorus, sodium, potassium, and chloride in kittens varied among age groups, being significantly (P < 0.01) different for potassium and calcium in young kittens (4 to 6 weeks) and older kittens (≥ 7 weeks).

Free access
in American Journal of Veterinary Research

SUMMARY

Cardiovascular responses to sublethal endotoxin infusion (Escherichia coli, 50 μg/ml in lactated Ringer solution at 100 ml/h until pulmonary arterial pressure increased by 10 mm of Hg) were measured 2 times in 5 standing horses. In a 2-period crossover experimental design, horses were either administered hypertonic (2,400 mosm/kg of body weight, iv) or isotonic (300 mosm/kg, iv) NaCl solution after endotoxin challenges. Each solution was administered at a dose of 5 ml/kg (infusion rate, 80 ml/min). Complete data sets (mean arterial, central venous, and pulmonary arterial pressures, pulmonary arterial blood temperature, cardiac output, total peripheral vascular resistance, heart rate, plasma osmolality, plasma concentration of Na, K, Cl, and total protein, blood lactate concentration, and pcv) were collected at 0 (baseline, before endotoxin infusion), 0.25, 1, 1.5, 2, 2.5, 3, 3.5, 4, and 4.5 hours after initiation of the endotoxin infusion. Blood constituents alone were measured at 0.5 hour and cardiovascular variables alone were evaluated at 0.75 hour. By 0.25 hour, endotoxin infusion was completed, a data set was collected, and saline infusion was initiated. By 0.75 hour, saline solutions had been completely administered.

Mean (± sem) cardiac output decreased (99.76 ± 3.66 to 72.7 ± 2.35 ml/min/kg) and total peripheral resistance (1.0 ± 0.047 to 1.37 ± 0.049 mm of Hg/ml/min/kg) and pulmonary arterial pressure (33.4 ± 0.86 to 58.3 ± 1.18 mm of Hg) increased for both trials by 0.25 hour after initiation of the endotoxin infusion and prior to fluid administration. For the remainder of the protocol, cardiac output was increased and total peripheral resistance was decreased during the hypertonic, compared with the isotonic, saline trial. Cardiac output was decreased and total peripheral resistance was increased during the isotonic saline trial, compared with baseline values. Both trials were associated with increased blood lactate concentration, but lactate values during the isotonic saline trial were greater and remained increased above baseline values for a longer period (4 hours) than during the hypertonic saline trial (2.5 hours). It was concluded for this model of endotoxemia, that iv administered hypertonic saline solution was associated with more-desirable cardiovascular and metabolic responses than was an equal volume of isotonic saline solution.

Free access
in American Journal of Veterinary Research

Summary

To evaluate the clinical, laboratory, and histologic effects of 2 methods of treatment for infectious arthritis in horses, Staphylococcus aureus (3.4 to 3.9 × 103 colony-forming units) was inoculated into the tarsocrural joints of 8 horses on day 0. Each horse was treated with phenylbutazone (2 g, po, q 24 h) and gentamicin sulfate (2.2 mg/kg of body weight, iv, q 8 h) for 14 days. On day 2, general anesthesia was induced, and each horse had 1 tarsocrural joint treated by arthrotomy, with removal of accessible fibrin and lavage with 3 L of sterile balanced electrolyte solution. An indwelling plastic drain was placed in the standing horse to provide a means for lavage with 3 L of balanced electrolyte solution twice daily for 72 hours. The contralateral tarsocrural joint was treated via arthroscopic debridement, synovectomy, and lavage with 3 L of balanced electrolyte solution. Arthrotomy and arthroscopic portals were allowed to heal by second intention. Lameness and thermographic examinations, analysis and bacteriologic culture of synovia, cbc, and wbc differential count were performed prior to inoculation and on days 1, 3, 6, 8, and 13. On day 14, each horse was euthanatized, and the joints were measured, opened, and photographed. Synovium and articular cartilage were obtained for semiquantitative histologic (H&E stain) and histochemical (safranin O fast green stain) evaluation. Lameness and joint circumference were significantly (P < 0.05) greater in limbs treated by arthroscopy, synovectomy, and lavage. Arthrotomy with lavage eliminated the S aureus infection significantly (P < 0.05) earlier than arthroscopy, synovectomy, and lavage; however, both treatments eliminated the infection in all but a single joint. Contamination with other organisms (Streptococcus spp and Enterobacter spp) developed significantly (P < 0.05) more often in joints treated by arthrotomy. These results suggested that arthrotomy with lavage was more effective in eliminating joint infection by providing better drainage than arthroscopy, synovectomy, and lavage; however, arthrotomy had a higher risk of ascending bacterial contamination of the joint.

Free access
in American Journal of Veterinary Research