Myophosphorylase deficiency (glycogen storage disease Type V) in a herd of Charolais cattle in New Zealand: Confirmation by PCR-RFLP testing

AIM: To describe a disease of muscle in Charolais calves and confirm the putative diagnosis of inherited myophosphorylase deficiency.

METHODS: Variously stained paraffin sections of muscle prepared from affected calves were used to describe the lesions. A polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) test was developed and applied to affected calves, their sires, dams and other individuals.

RESULTS: The lesions were those of rhabdomyolysis of skeletal muscles and sub-sarcolemmal spaces in normal fibres. The PCR-RFLP test confirmed the expected mutation for phosphorylase deficiency of Charolais cattle in two affected calves. In addition, sires, dams and other closely-related individuals of four affected calves tested as heterozygous for the mutation. Other apparently unrelated animals also tested as heterozygous.

CONCLUSIONS: The diagnosis of myophosphorylase deficiency was confirmed. The PCR-RFLP test is suitable for use in controlling this recessively-inherited disorder as it can diagnose heterozygous individuals that are otherwise clinically normal.     

Owner compliance with short term antimicrobial medication in dogs

Summary: The degree to which dog owners complied with instructions to administer a 5 to 10 day course of antimicrobial medication to their pets was assessed using microprocessor based monitoring devices. Twenty two clients gave an average of 84% of prescribed doses of amoxycillin-clavulanate. No difference was found between twice and thrice daily dosing regimens in the overall percentage of prescribed doses given. However, timing of doses was far from ideal in many cases and only 34% of doses were given within the designated optimum time period. Adherence to desired dosing intervals tended to be better with twice daily than with thrice daily dosing, although the difference was statistically insignificant.     

The impact of MK-467 on sedation,heart rate and arterial blood pressure after intramuscular coadministration with dexmedetomidine in conscious cats

Objective

To study the effects of MK-467, a peripheral α₂-adrenoceptor antagonist, on sedation, heart rate and blood pressure after intramuscular (IM) coadministration with 25 μg kg^?1 of dexmedetomidine in cats.

Effects of epidurally administered morphine or buprenorphine on the thermal threshold in cats

Objective: To determine the antinociceptive effects of epidural administration of morphine or buprenorphine in cats by use of a thermal threshold model. ANIMALS: 6 healthy adult cats. PROCEDURES: Baseline thermal threshold was determined in duplicate. Cats were anesthetized with isoflurane in oxygen. Morphine (100 microg/kg diluted with saline [0.9% NaCl] solution to a total volume of 0.3 mL/kg), buprenorphine (12.5 microg/kg diluted with saline solution to a total volume of 0.3 mL/kg), or saline solution (0.3 mL/kg) was administered into the epidural space according to a Latin square design. Thermal threshold was determined at various times up to 24 hours after epidural injection. RESULTS: Epidural administration of saline solution did not affect thermal threshold. Thermal threshold was significantly higher after epidural administration of morphine and buprenorphine, compared with the effect of saline solution, from 1 to 16 hours and 1 to 10 hours, respectively. Maximum (cutout) temperature was reached without the cat reacting in 0, 74, and 11 occasions in the saline solution, morphine, and buprenorphine groups, respectively. CONCLUSIONS AND CLINICAL RELEVANCE: Epidural administration of morphine and buprenorphine induced thermal antinociception in cats. At the doses used in this study, the effect of morphine lasted longer and was more intense than that of buprenorphine.     

Comparison of methods to assess dog owners' therapeutic compliance

Objective To compare different methods for assessing the compliance of veterinary clients administering medication to their dogs.
Procedure Thirty-one owners whose dogs were prescribed amoxycillin-clavulanate, twice and thrice daily, for a duration of five to seven days were recruited from three Sydney veterinary hospitals. Compliance was assessed by electronic monitoring devices, return medication counts, client self-reports and veterinarians' estimation of likely compliance.
Results Electronic monitoring showed owners administered on average 84% (range 7 to 104%) of prescribed medication to their dogs. Both return medication counts and client self-reports tended to overestimate therapeutic compliance when compared with electronic monitoring. When questioned, the majority of owners (71%) claimed perfect compliance with the prescribed regimen. No correlation was found between veterinarians' estimates of owner compliance and that assessed electronically.
Conclusion Electronic monitoring provided valuable information on dose timing and variation, but proved costly and difficult to employ in veterinary practice. Simplicity and low cost of return medication counts makes this method attractive for use in veterinary compliance studies. Client self-reports reliably detected some noncompliers and permitted identification of individual problems or errors. For practical purposes a combination of return medication counts and client self-reports may have merit in future veterinary compliance studies.     

Hemodynamic effects of nitrous oxide in isoflurane-anesthetized cats

OBJECTIVE: To determine the hemodynamic effects of nitrous oxide in isoflurane-anesthetized cats. ANIMALS: 12 healthy adult domestic shorthair cats. PROCEDURE: Cats were anesthetized by administration of isoflurane in oxygen. After instruments were inserted, end-tidal isoflurane concentration was set at 1.25 times the individual minimum alveolar concentration, and nitrous oxide was administered in a Latin-square design at 0, 30, 50, and 70%. Each concentration was administered for 25 minutes before measurements were obtained to allow for stabilization. Heart rate; systemic and pulmonary arterial pressures; central venous pressure; pulmonary artery occlusion pressure; cardiac output; body temperature; arterial and mixed-venous pH, PCO2, PO2, and hemoglobin concentrations; PCV; and total protein and lactate concentrations were measured before and during noxious stimulation for each nitrous oxide concentration. Arterial and mixed-venous bicarbonate concentrations and oxygen saturation, cardiac index, stroke index, rate-pressure product, systemic and pulmonary vascular resistance indices, left and right ventricular stroke work indices, arterial and mixed-venous oxygen contents, oxygen delivery, oxygen consumption, oxygen extraction ratio, alveolar-to-arterial oxygen difference, and venous admixture were calculated. RESULTS: Arterial pressure, central venous pressure, pulmonary arterial pressure, rate-pressure product, systemic and pulmonary vascular resistance indices, arterial PCO2, and PCV increased during administration of 70% nitrous oxide. Arterial and mixed-venous pH, mixed-venous PO2, and alveolar-to-arterial oxygen difference decreased during administration of 70% nitrous oxide. Results before and during noxious stimulation were similar. CONCLUSIONS AND CLINICAL RELEVANCE: Administration of 70% nitrous oxide to isoflurane-anesthetized cats resulted in improved arterial pressure, which was related to a vasoconstrictive effect.     

Evaluation of a portocaval venograft and ameroid ring for the occlusion of intrahepatic portocaval shunts in dogs

OBJECTIVE:To evaluate the use of a portocaval venograft and ameroid constrictor in the surgical management of intrahepatic portosystemic shunts (PSS). STUDY DESIGN: Prospective, clinical study. Animal Population: Ten client-owned dogs with intrahepatic PSS. METHODS: Portal pressure was measured after temporary suture occlusion of the intrahepatic PSS. In dogs with an increase in portal pressure greater than 8 mm Hg, a single extrahepatic portocaval shunt was created using a jugular vein. An ameroid ring was placed around the venograft and the intrahepatic PSS was attenuated. Transcolonic pertechnetate scintigraphy was performed before surgery, 5 days after surgery, and 8 to 10 weeks after surgery. Dogs with continued portosystemic shunting were evaluated further by laparotomy or portography. Clinical outcome and complications were recorded. RESULTS: Mean (+/- SD) portal pressure increased from 6 +/- 3 to 19 +/- 6 mm Hg with PSS occlusion; in all 10 dogs, the increase in portal pressure was greater than 8 mm Hg. There were no intraoperative complications, and, after creation of the portocaval shunt, the intrahepatic PSS could be completely ligated in 8 of 10 dogs. The final portal pressure was 9 +/- 4 mm Hg. Postoperative complications included coagulopathy and death (1 dog), ascites (3 dogs), and incisional discharge (3 dogs). Five of 8 dogs had continued portosystemic shunting at 8 to 10 weeks after surgery. Multiple extrahepatic PSS were demonstrated in 4 of these dogs. Clinical outcome was excellent in all 9 surviving dogs. CONCLUSIONS AND CLINICAL SIGNIFICANCE: The surgical technique resulted in a high incidence of multiple extrahepatic PSS. Short-term clinical results were promising, but long-term outcome must be evaluated further.     

Pharmacokinetics of buprenorphine following intravenous and buccal administration in cats,and effects on thermal threshold

This study reports the pharmacokinetics of buprenorphine, following i.v. and buccal administration, and the relationship between buprenorphine concentration and its effect on thermal threshold. Buprenorphine (20 μg/kg) was administered intravenously or buccally to six cats. Thermal threshold was determined, and arterial blood sampled prior to, and at various times up to 24 h following drug administration. Plasma buprenorphine concentration was determined using liquid chromatography/mass spectrometry. Compartment models were fitted to the time–concentration data. Pharmacokinetic/pharmacodynamic models were fitted to the concentration‐thermal threshold data. Thermal threshold was significantly higher than baseline 44 min after buccal administration, and 7, 24, and 104 min after i.v. administration. A two‐ and three‐compartment model best fitted the data following buccal and i.v. administration, respectively. Following i.v. administration, mean ± SD volume of distribution at steady‐state (L/kg), clearance (mL·min/kg), and terminal half‐life (h) were 11.6 ± 8.5, 23.8 ± 3.5, and 9.8 ± 3.5. Following buccal administration, absorption half‐life was 23.7 ± 9.1 min, and terminal half‐life was 8.9 ± 4.9 h. An effect‐compartment model with a simple effect maximum model best predicted the time‐course of the effect of buprenorphine on thermal threshold. Median (range) k_e0 and EC50 were 0.003 (0.002–0.018)/min and 0.599 (0.073–1.628) ng/mL (i.v.), and 0.017 (0.002–0.023)/min and 0.429 (0.144–0.556) ng/mL (buccal).     

Evaluation of von Willebrand Factor During Pregnancy,Lactation and Oestrous Cycle in Bitches Affected and Unaffected by von Willebrand Disease

Plasmatic concentrations of von Willebrand Factor (vWF) increase during pregnancy in humans and dogs; however the mechanism of such increase is still not well defined. The aims of this study were: (i) to evaluate changes in vWF concentration during pregnancy and during the subsequent oestrous cycle in bitches affected and unaffected by von Willebrand Disease (vWD); (ii) to correlate the vWF levels and cortisol levels in both groups. Seven vWD affected (GI) and nine unaffected (GII) bitches were used. The animals were assessed during pregnancy, parturition, lactation and non‐gestational oestrous cycle in 11 moments (Pregnancy 1, Pregnancy 2, Parturition, Lactation 1, Lactation 2, Lactation 3, Anestrus, Proestrus, Oestrus, Diestrus 1, and Diestrus 2). The following tests were performed; measurement of von Willebrand factor antigen (vWF:Ag), albumin and cortisol. In both groups, vWF concentration remained stable during the non‐gestational oestrous cycle, but increased during pregnancy, with the highest value observed at parturition. Increases of 70% and 124% in vWF were seen in GI and GII, respectively, compared to anestrus. No correlation was found between vWF and cortisol. Values of vWF:Ag changed during pregnancy, with a peak at parturition, both in vWD affected and unaffected animals. Values of vWF were not altered in the different phases of the oestrous cycle following pregnancy in both groups. Evaluation of vWF during pregnancy can cause false negative results for vWD, but assessment can be performed at any point in the oestrous cycle of non‐pregnant bitches.