Search Results

You are looking at 1 - 10 of 23 items for

  • Author or Editor: Susan J. Tornquist x
  • Refine by Access: All Content x
Clear All Modify Search
in Journal of the American Veterinary Medical Association

Abstract

Objective—To investigate glucose tolerance and insulin sensitivity in llama crias.

Animals—7 llamas (age range, 14 to 30 days).

Procedure—On each of 2 sequential days, crias were administered glucose (0.5 g/kg) via rapid IV injection. On 1 day (randomly determined for each cria), regular insulin (0.2 U/kg) or 0.9% NaCl solution (0.002 mL/kg) was administered IV 15 minutes after glucose administration. Blood samples were collected before (baseline) and at 5, 15, 30, 45, 60, 90, 120, 180, and 240 minutes after glucose administration for determination of plasma glucose and insulin concentrations; fractional turnover rates and plasma half-life of glucose were calculated. The data were compared over time and between days (ie, between glucose treatments with and without insulin administration).

Results—A peak plasma glucose concentration of 342 ± 47 mg/dL was detected at 5 minutes after glucose administration and llamas cleared glucose from plasma within 60 minutes; at 15 minutes, plasma insulin concentration attained a peak value of 33 ± 13 µU/mL (ie, triple the baseline value). During the 15- to 45-minute interval, fractional turnover rate of glucose was 1.10 ± 0.24%/min and plasma half-life was 65.7 ± 13.4 minutes. Insulin significantly increased glucose turnover and resulted in hypoglycemia within 75 minutes of administration.

Conclusions and Clinical Relevance—Healthy immature llamas have glucose tolerance and insulin sensitivity superior to that of adults. However, whether sick crias retain the pancreatic sufficiency and tissue responsiveness that are likely responsible for the rapid glucose clearance in healthy individuals is not known. (Am J Vet Res 2005;66:1013–1017)

Full access
in American Journal of Veterinary Research

Abstract

Objective—To describe the metabolic effects of epinephrine administration in New World camelids and investigate whether these effects are influenced by administration of insulin.

Animals—6 llamas and 8 alpacas (all adult castrated males).

Procedure—Prior to each experiment, food was withheld from camelids for 8 hours. On each of 2 consecutive days, alpacas were administered epinephrine (10 mg/kg, IM; time 0); alpacas were randomly assigned to receive regular insulin (0.2 U/kg, IV) immediately after epinephrine administration on one of those days. In llamas, the experiment was performed once after administration of epinephrine only. At 0, 30, 60, 90, 120, 150, 180, 210, and 240 minutes after treatment, blood samples were collected and several serum or plasma biochemical variables were assessed; in addition, plasma samples from llamas were assessed for insulin concentrations. Data were compared between days (alpacas only) and between time points.

Results—Administration of epinephrine induced mobilization of glucose, triglycerides, nonesterified fatty acids, and β-hydroxybutyrate. A small increase in endogenous insulin concentration was detected in epinephrine-treated llamas, compared with baseline values. Overall, insulin administration decreased, negated, or delayed the epinephrine-associated increases in serum or plasma concentrations of circulating energy substrates, except that it augmented the epinephrine-associated increase in concentration of triglycerides.

Conclusions and Clinical Relevance—Epinephrine appeared to mobilize energy substrates in camelids and hence may be involved in the pathogenesis of disorders of glucose and fat metabolism. Insulin appeared to antagonize most of these effects, and its administration may have therapeutic value in camelids. (Am J Vet Res 2004;65:1692–1696)

Full access
in American Journal of Veterinary Research

Abstract

Objective—To evaluate the effects of long-acting insulin on glucose clearance in alpacas.

Animals—8 adult castrated alpacas.

Procedure—On 2 days, food was withheld from alpacas for 8 hours. Alpacas were randomly allocated to receive an SC injection of long-acting insulin (0.4 U/kg) or saline (0.9% NaCl) solution 1 hour before the first of 3 administrations of glucose (at 60, 480, and 1,200 minutes after treatment) on day 1 and the alternate treatment and procedure on day 2. Plasma glucose concentration was determined before and 15, 45, 120, and 240 minutes after each glucose administration, and fractional turnover rates were calculated. The data were compared between alpacas with and without insulin administration and among the 3 glucose administrations for each day.

Results—Compared with sham-treated alpacas, insulin-treated alpacas had significantly lower blood glucose concentrations from 180 to 600 minutes after treatment; they also had glucose concentrations significantly below baseline values from 120 to 480 minutes, at which time the mean glucose concentration was in the hypoglycemic range. Also, mean fractional turnover of glucose was significantly higher in insulintreated alpacas from 105 through 300 minutes.

Conclusions and Clinical Relevance—Compared with known effects of regular insulin in alpacas, the action of long-acting insulin was of slower onset but longer lasting; its administration may induce hypoglycemia, even in alpacas that receive glucose. To maintain the hypoglycemic effect, long-acting insulin may have to be administered more than once daily and blood glucose concentration should be monitored to avoid hypoglycemic complications in alpacas. (Am J Vet Res 2004;65:1688–1691)

Full access
in American Journal of Veterinary Research
in American Journal of Veterinary Research

Abstract

Objective—To develop a PCR assay for Candidatus Mycoplasma haemolamae (CMhl) infection in alpacas and use it to study the efficacy of oxytetracycline treatment and development of a subclinical carrier state.

Animals—8 healthy adult alpacas.

Procedures—Alpacas initially had negative results for CMhl in blood samples via PCR assay and were experimentally infected with CMhl; 4 were treated with oxytetracycline, and 4 were not treated. All were monitored regularly via PCR assay, blood smear examination, PCV, rectal temperature, and physical examination. At 6 months after treatment, all alpacas were immunosuppressed by administration of dexamethasone and tested for CMhl.

Results—7 of 8 alpacas had positive PCR assay results 4 to 6 days after experimental infection. When organisms were detectable on a blood smear, they were seen 2 to 6 days after positive results of PCR assay. Infection was often associated with mild anemia that was usually transient. No alpacas became hypoglycemic. Oxytetracycline treatment was not associated with faster clearance of organisms or resolution of anemia, and 4 of 4 treated alpacas still had positive results of PCR assay when immunosuppressed 6 months later; 0 of 3 nontreated alpacas had positive results of PCR assay following immunosuppression. Transient fever was detected in 3 alpacas during immunosuppression.

Conclusions and Clinical Relevance—The PCR assay was more sensitive than blood smear examination for detection of infection. Clinical signs, anemia, and fever were not necessarily associated with infection. Oxytetracyline administration did not consistently clear CMhl infection. Although treated with oxytetracycline, infected alpacas remained chronic carriers.

Full access
in American Journal of Veterinary Research
in Journal of the American Veterinary Medical Association
in American Journal of Veterinary Research

Abstract

Objective—To determine whether ϵ-aminocaproic acid (EACA) administered IV affects hemostasis and fibrinolysis in clinically normal horses and ponies.

Animals—20 clinically normal adult horses and ponies.

Procedures—Blood samples were collected 24 hours before (baseline) and 1 and 5 hours after IV administration of a low dose (30 mg/kg) or high dose (100 mg/kg) of EACA. Platelet count, fibrinogen concentration, prothrombin time, partial thromboplastin time (PTT), D-dimer concentration, α2-antiplasmin activity, and thrombin-antithrombin complex concentration were measured. Values at 1 and 5 hours were compared with baseline values.

Results—1 hour after administration of a low dose of EACA, mean fibrinogen concentration was significantly lower than baseline concentration. Mean PTT was significantly shorter than the baseline value 5 hours after administration of a low dose of EACA. One hour after administration of 100 mg of EACA/kg, mean α2-antiplasmin activity was significantly higher than baseline activity. Mean fibrinogen concentration was significantly lower than baseline concentration 1 and 5 hours after administration of a high dose of EACA. Mean PTT was significantly shorter than the baseline value 5 hours after administration of a high dose of EACA.

Conclusions and Clinical Relevance—IV administration of 30 and 100mg of EACA/kg to clinically normal horses significantly modified some laboratory measures of hemostasis, consistent with its known antifibrinolytic effects. Although enhanced clot maintenance and diminished bleeding were not directly assessed, the clinical use of EACA may benefit some patients. ( Am J Vet Res 2005;66:313–318)

Full access
in American Journal of Veterinary Research

Abstract

Objective—To evaluate the effects of exogenous insulin on clearance of exogenous glucose in alpacas.

Animals—7 adult castrated male alpacas.

Procedure—Prior to each of 2 trials, food was withheld for 8 hours. Glucose (0.5 g/kg of body weight) was then administered by rapid IV infusion. During 1 of the trials, regular insulin (0.2 U/kg, IV) was also administered 15 minutes later. Blood was collected immediately before (0 minutes) and 15, 20, 25, 30, 45, 60, 90, 120, 180, and 240 minutes after glucose administration. Plasma concentrations of glucose and lactate were determined, and glucose fractional turnover rate and plasma half-life were calculated.

Results—Insulin treatment caused a significant increase in fractional turnover rate of glucose and plasma lactate concentration. Plasma glucose concentrations were less in insulin-treated alpacas from 30 minutes after glucose administration (15 minutes after insulin administration) until the conclusion of each trial, compared with nontreated alpacas. In addition, plasma glucose concentration in insulin-treated alpacas returned to baseline values 1 hour sooner than in the nontreated group.

Conclusion and Clinical Relevance—Glucose uptake in alpacas improves after insulin treatment, suggesting that administration of exogenous insulin will increase the therapeutic and decrease the pathologic effects of exogenous glucose administered to hypoglycemic alpacas. However, alpacas and other New World camelids should be monitored carefully during treatment with glucose or insulin, because these species appear to be partially insulin resistant. (Am J Vet Res 2001;62:1544–1547)

Full access
in American Journal of Veterinary Research