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SUMMARY

A technique for transvenous endomyocardial biopsy of the right ventricle was developed and evaluated for safety and efficacy in anesthetized healthy cats positioned in left lateral recumbency. At least 6 endomyocardial biopsy specimens were obtained from the right ventricle or interventricular septum of 11 cats. In 4 cats, the right jugular vein was torn during attempts to pass the introducing catheter into the right ventricle; however, in only 1 cat did this preclude catheter passage. This cat's heart was biopsied via the left jugular vein. Except for damage to the jugular vein, complications were infrequent, and the biopsy procedure was well tolerated by all cats.

Free access
in American Journal of Veterinary Research

Objective

To assess degree of oxidative stress and antioxidant concentrations in dogs with idiopathic dilated cardiomyopathy (IDCM).

Design

Prospective study.

Animals

18 dogs with IDCM and 16 healthy control dogs.

Procedure

Concentrations of malondialdehyde (an indicator of oxidative stress); vitamins A, C, and E; glutathione peroxidase; and superoxide dismutase were measured.

Results

Glutathione peroxidase concentration was significantly increased in dogs with IDCM, compared with control dogs. Vitamin A and superoxide dismutase concentrations were not significantly different between groups. A negative correlation was found between disease severity and plasma vitamin E concentration. Disease severity was not correlated with concentrations of other antioxidants. Medications did not significantly affect oxidant or antioxidant concentrations.

Conclusions and Clinical Relevance

The change in glutathione peroxidase concentration and the correlation between vitamin E concentration and disease severity suggest that the oxidant-antioxidant system may play a role in development of IDCM. (J Am Vet Med Assoc 1999;215:644–646)

Free access
in Journal of the American Veterinary Medical Association

Abstract

Objective

To compare results of 6 commercially available milk antimicrobial screening tests with results of liquid chromatography (LC) when testing milk samples from individual cows treated for mild clinical mastitis by intramammary (IMM) infusion with amoxicillin or penicillin G.

Animals

6 cows with noninduced clinical mastitis: 3 treated by IMM infusion with amoxicillin and 3 treated by IMM infusion with penicillin G.

Procedure

Composite milk samples were collected before, during, and after treatment. Samples were assayed by use of the screening tests and their results and those of LC were compared. The LC results were assumed to represent the true result.

Results

Results of screening tests compared well with results of LC, with agreement of 94%. Positive screening test results for samples containing drug values below the established tolerance or safe level, as evaluated by LC, were obtained from 2 cows in which abnormal milk, as well as marked increases in composite milk somatic cell count, were observed. With the exception of 1 test in 1 cow, all screening tests had negative results at the end of the labeled milk-withholding time.

Conclusions and Clinical Implications

On the basis of results of the limited sample reported, the screening tests appeared to provide good agreement overall, compared with LC results, when testing milk of individual cows treated by IMM infusion with amoxicillin or penicillin G. Positive screening test results for milk samples containing amoxicillin or penicillin G at values below the established tolerance or safe level, as evaluated by LC, may occasionally be obtained. (Am J Vet Res 1998;59:1096-1100)

Free access
in American Journal of Veterinary Research

Objective

To determine the prevalence of clinical signs that affect quality of life in dogs with congestive heart failure (CHF), and to characterize the role of these clinical signs in the decision for euthanasia.

Design

Prospective study.

Animals

38 dogs with CHF that had been euthanatized within the preceding 22 months.

Procedure

Clinical information and factors affecting the decision for euthanasia were reviewed and recorded from medical records of dogs with CHF. Each owner was then interviewed via telephone to determine whether their dog had anorexia or other clinical signs of disease prior to euthanasia, their perception of their dogs’ quality of life, and the most important factor and contributing factors that influenced the decision to euthanatize their dog.

Results

Of the 38 dogs with CHF, > 70% had weakness (35 dogs), coughing (33), anorexia (32), weight loss (32), dyspnea (30), or exercise intolerance (28) reported by their owners. Factors often named by owners as most important in the decision for euthanasia were poor prognosis given by the attending veterinarian, recurrent clinical signs of CHF (ie, coughing, dyspnea, or ascites), and poor quality of life. Weakness, anorexia, and recurrent clinical signs of CHF were the most common contributing factors in the decision for euthanasia.

Clinical Implications

Anorexia, weight loss, and exercise intolerance are common in dogs euthanatized because of CHF. The importance of quality of life and poor prognosis in making a decision for euthanasia suggests that addressing these factors may improve patient management. (J Am Vet Med Assoc 1999;214:1201–1204)

Free access
in Journal of the American Veterinary Medical Association

SUMMARY

A radioimmunoassay test for tetracyclines (Charm II) was compared with high-pressure liquid chromatography (hplc) for detection of oxytetracycline (otc) residues in milk samples from individual lactating cows. Oxytetracycline was administered by 1 of 3 routes (IV, IM, or intrauterine) to 21 lactating dairy cows. A total of 292 duplicate milk samples were collected from milkings before and through 156 hours after otc administration. Concentration of otc in these samples was determined by use of the Charm II test and an hplc method with a lower limit of quantitation, approximately 2 ng of otc/ml. Samples were also classified with respect to presence of otc residues relative to the fda safe concentration (< 30 ng/ml), using the Charm II (by control point determination) and hplc methods.

There was a significant (P < 0.05) difference between test methods in classification of milk samples with respect to presence or absence of otc at the fda safe concentration. A total of 48 of the 292 test results (16.4%) did not agree. Using the hplc test results as the standard with which Charm II test results were compared, 47 false presumptive-violative test results and 1 false presumptive-nonviolative Charm fi test result (a sample containing 31 ng of otc/ml, as evaluated by hplc) were obtained. The samples with false presumptive-violative Charm fi results contained < 30 ng of otc/ml, as evaluated by hplc.

In some respects, the Charm H test performed appropriately as a screening test to detect otc residues in milk samples from individual cows. However, the tendency for the test to yield presumptive-violative test results at otc concentrations lower than the fda safe concentration (as evaluated by hplc), suggests that caution should be exercised in using the test as the sole basis on which a decision is made to reject milk. As indicated by the manufacturer, presumptive-violative Charm II test results should be confirmed by additional testing. Although not specifically evaluated, the tendency for misclassification of milk samples as presumptive-violative by the Charm II test may or may not occur in commingled milk, compared with milk samples from individual cows.

Free access
in American Journal of Veterinary Research

SUMMARY

A technique for transvenous endomyocardial biopsy of the right ventricle was developed and evaluated for safety and efficacy in healthy dogs and dogs with dilated cardiomyopathy positioned in lateral recumbency. This technique allowed acquisition of multiple biopsy specimens from the right ventricle of each of 22 hemodynamically normal dogs and 40 of 42 dogs with congestive heart failure. In 2 dogs with dilated cardiomyopathy, transvenous access to the right ventricle could not be achieved, but left ventricular biopsy was performed without complication. Complications were infrequent, and dogs recovered to at least their baseline status within 48 hours. Evaluation of the efficacy and complication rate of the procedure with each of the 2 biopsy instruments currently available identified no differences between them.

Free access
in American Journal of Veterinary Research

Abstract

Objective—To describe the disposition of and pharmacodynamic response to atenolol when administered as a novel transdermal gel formulation to healthy cats.

Animals—7 healthy neutered male client-owned cats.

Procedures—Atenolol was administered either orally as a quarter of a 25-mg tablet or as an equal dose by transdermal gel. Following 1 week of treatment, an ECG and blood pressure measurements were performed and blood samples were collected for determination of plasma atenolol concentration at 2 and 12 hours after administration.

Results—2 hours after oral administration, 6 of 7 cats reached therapeutic plasma atenolol concentrations with a mean peak concentration of 579 ± 212 ng/mL. Two hours following transdermal administration, only 2 of 7 cats reached therapeutic plasma atenolol concentrations with a mean peak concentration of 177 ± 123 ng/mL. The difference in concentration between treatments was significant. Trough plasma atenolol concentrations of 258 ± 142 ng/mL and 62.4 ± 17 ng/mL were achieved 12 hours after oral and transdermal administration, respectively. A negative correlation was found between heart rate and plasma atenolol concentration.

Conclusions and Clinical Relevance—Oral administration of atenolol at a median dose of 1.1 mg/kg every 12 hours (range, 0.8 to 1.5 mg/kg) in cats induced effective plasma concentrations at 2 hours after treatment in most cats. Transdermal administration provided lower and inconsistent plasma atenolol concentrations. Further studies are needed to find an effective formulation and dosing scheme for transdermal administration of atenolol.

Full access
in American Journal of Veterinary Research

Abstract

Objective—To compare plasma fatty acid concentrations and the relationships of fatty acids to arrhythmias in Boxers versus Doberman Pinschers.

Animals—38 Boxers and 13 Doberman Pinschers.

Procedures—Boxers and Doberman Pinschers evaluated via Holter recording and for which a blood sample was available were included. Echocardiograms were performed in 49 of 51 dogs. The number of ventricular premature complexes (VPCs)/24 h was counted and fatty acids analyzed. Plasma fatty acid concentrations and VPCs/24 h, as well as correlations between the 2 variables, were compared between the 2 breeds.

Results—Compared with the Doberman Pinschers, Boxers had significantly higher plasma concentrations of γ-linolenic acid but lower concentrations of arachidonic acid. Total n-6 fatty acids and total polyunsaturated fatty acid concentrations were higher in Doberman Pinschers. There were significant, but weak, positive correlations between VPCs and oleic acid, total n-3 fatty acids, and total n-9 fatty acids in Boxers but not in Doberman Pinschers.

Conclusions and Clinical Relevance—Data suggested that plasma fatty acid concentrations may differ between Boxers and Doberman Pinschers and that the relationship between fatty acid concentrations and VPCs may be different between these 2 breeds.

Full access
in American Journal of Veterinary Research