A TechniaueI for the Examination of Lactate Dehydrogenase Isoenzymes in the Dog

Abstract— A technique and apparatus for the electrophoretic separation and staining of lactate dehydrogenase isoenzymes in canine sera is described. The technique is a modification of the agar gel electrophoretic method of Wieme (1959) and is relatively simple, reproducible and inexpensive, allowing visual and densi tometric evaluation of the relative quantities of each enzyme fraction. Cellulose acetate and five different types of commercially available agar were examined for their suitability as a support medium for LDH isoenzyme separation using canine sera. Risumé—On décrit une technique et un appareil pour la séparation électrophorttique et la coloration des enzymes du groupe de la deshydrogénase lactique dans le sérum de chien. La technique at une modification de la méthode électrophorétique en gel d'agar de Wieme (1959) et elle est relativement simple, fidéle et peu couteuse, et elle permet une évaluation visuelle et densimétrique des quantités relatives de chaque fraction enzymatique. Les qualités de l'acétate de cellulose et de 5 types différents d'agar à notre disposition dam le commerce ont été examiné en temps que milieu support pour la séparation des enzymes du groupe lacto-deshydrogénase du sérum de chien. Zusammenfassuug—Eine Methode und die Apparatur für die elektrophoretische Trennung und Färbung von Lactatdehydrogenaseioenzymen in Hundeseren werden beschrieben. Die Methode it eine Modifikation der elektrophoretischen Agargelmethode von Wieme (1959) und relativ einfach, reproduzierbar und billig; sie ermöglicht die visuelle und densitometrische Feststellung der relativen Mengen jeder Fermentfraktion. Celldoseacetat und fiinf verschiedene Typen handelsmässigen Agars wurden hinsichtlich ihrer Eignung als Trägersubstanz für die LDH-Isoenzymtrennung von Hundeseren benutzt.     

Infection by leptospires of the Pomona serogroup in cattle and pigs in south west England

Leptospires belonging to the Pomona serogroup were isolated from calves involved in two outbreaks of acute haemolytic disease which were characterised by jaundice, haemoglobinuria and high death rates. Retrospective case studies in which serological evidence of Pomona serogroup infection was found are also presented. Serovar pomona is the leptospire of the Pomona serogroup most commonly incriminated in clinical disease in domestic species, but the organisms isolated in this study were antigenically different to pomona and may represent a new serovar. The limited information available on the epidemiology of sporadic infection with leptospires of the Pomona serogroup in domestic species in the south west of England supports the contention that a serovar other than pomona is involved.     

Proliferative renal myxosporidiosis in spawning coho salmon (Oncorhynchus kisutch) in British Columbia and Washington

An unidentified myxosporean parasite (CKX) is described from the kidney of approximately 80% of spawning coho salmon Oncorhynchus kisutch (Walbaum) in British Columbia, Canada and Washington, United States of America. Morphological features were described using light and electron microscopy. Sequencing of polymerase chain reaction (PCR) amplified 18S ribosomal RNA gene and in situ hybridisation were used to further characterise CKX. The parasite occurred with a focal distribution within tubule epithelial cells, the tubule lumen and the interstitium as primary cells containing from one to at least 16 secondary cells. Luminal stages were degenerate and sporogony was not observed. In situ hybridisation using a digoxygenin-labelled DNA probe confirmed CKX to be the source of DNA used in PCR analyses. CKX 18S rDNA sequences were most similar (97%) to those of Sphaerospora oncorhynchi. Phylogenetic analysis revealed similarities among the 18S rDNA sequences of CKX, S. oncorhynchi and Myxidium lieberkuehni. CKX is hypothesised to be the abortive extrasporogonic development of a Sphaerospora sp. or Myxidium sp. occurring in immune-incompetent spawning and senescent salmon.     

An evaluation of mycophage therapy, chemotherapy and vaccination for control of Mycobacterium avium subsp. paratuberculosis infection

The control of ovine Johne's disease (OJD) is important for domestic trade, the viability of farming units and possibly also for public health. Current strategies in Australia have included quarantine and pasture spelling to decrease prevalence and shedding rates and reduce numbers of Mycobacterium paratuberculosis (Mptb) ingested by susceptible sheep. However, alternative procedures are needed and vaccination with Gudair has recently commenced. This review examines prospects for the control of OJD by chemotherapy, vaccination and mycophages. Current chemotherapeutic regimes for treatment of M. paratuberculosis in ruminants are prohibitively expensive and of dubious efficacy, and apart from environmental concerns, mycophage therapy lacks a track record of success against intracellular bacteria. There is substantial evidence that live and killed mycobacterial vaccines reduce the incidence of clinical disease and shedding rates in OJD. An appraisal of recent experimental results suggests that neonatal vaccination with a defined dose of M. paratuberculosis offers the best prospects for the induction of protective Th1-type immunity.     

Antimicrobial resistance of Salmonella isolated from finishing swine and the environment of 60 Alberta swine farms

The study objective was to describe and evaluate antimicrobial resistance profiles in Salmonella isolated from Alberta swine finishing farms. Salmonella isolates (n = 322) were obtained from 192 fecal and 84 environmental samples of the 60 Salmonella-positive swine finishing farms. Isolates were classified susceptible, intermediate or resistant based on NCCLS guidelines. More than half of the isolates (53.4%) were susceptible to all of the 18 antimicrobials in the testing panel. No resistance was observed to amikacin, amoxicillin/clavulanic acid, cefoxitin, ceftiofur, ceftriaxone, cephalothin, ciprofloxacin, imipenem or nalidixic acid. Less than 1% of isolates were resistant to apramycin, gentamicin and trimethoprim/sulfamethoxazole. Higher frequencies of resistance were observed for chloramphenicol (4.7%), ampicillin (7.8%), kanamycin (11.8%), sulfamethoxazole (21.1%), streptomycin (25.5%) and tetracycline (38.8%). Eleven Salmonella serovars had isolates with resistance to > or =3 antimicrobials. The most frequently resistant serovar was Salmonella Derby, with 27 (38.0%) isolates resistant to > or =3 antimicrobials, including resistance to five and six antimicrobials. An absence of resistance to cephalosporins and fluoroquniolones and a low proportion of isolates resistant to amikacin, amoxicillin/clavulanic acid, apramycin, gentamicin and trimethoprim/sulfamethoxazole are encouraging findings from public health and animal health perspectives. Frequent resistance observed for ampicillin, kanamycin, sulfamethoxazole, streptomycin and tetracycline, antimicrobials commonly used in veterinary medicine for decades, indicates an urgent need to utilize these antimicrobials more prudently if their benefits are to be preserved.     

Characterization of the pharmacokinetic and pharmacodynamic properties of the angiotensin-converting enzyme inhibitor, enalapril, in horses

The pharmacokinetics of enalapril (0.5 mg/kg i.v.) and the pharmacodynamics of enalapril (0.5 mg/kg PO) in 5 mares were investigated. After single i.v. dosing, concentrations of enalapril and enalaprilat, its active metabolite, were measured. Two weeks later, enalapril was administered by nasogastric tube. Potassium, creatinine, blood urea nitrogen (BUN), enalapril, and enalaprilat concentrations and angiotensin converting enzyme (ACE) activity were measured in serum. In addition, heart rate, blood pressure, digital venous blood gases, and lactate were measured. Two weeks later, enalapril was again administered by nasogastric tube. To mimic activation of the renin-angiotensin-aldosterone system, angiotensin I (0.5 microg/kg) was administered at fixed intervals, followed by blood-pressure and heart-rate measurement. The elimination half lives of enalapril and enalaprilat were 0.59 and 1.25 hours, respectively, after i.v. administration. After PO administration, enalapril and enalaprilat were not detectable in serum. There was a tendency (P = .0625) toward a decrease in ACE activity 45-120 minutes after enalapril administration, but ACE activity suppression was never > 16%. There was a tendency (P = .0625) toward a decrease in mean arterial pressure (MAP) 6-8 hours after enalapril administration. Serum concentrations of potassium, creatinine, and BUN and digital venous blood gases and lactate concentrations did not change. In response to angiotensin I, there was a tendency (P = .0625) toward a decrease in the MAP response 4-24 hours after enalapril administration. Single-dose enalapril at 0.5 mg/kg PO did not demonstrate significant availability, pharmacodynamic effect, or substantial suppression of ACE activity.