Genomic Imprinting in Canis familiaris

For the vast majority of mammalian genes, maternally- and paternally-derived alleles behave identically and are either expressed or repressed, regardless of whether they were inherited from egg or sperm. For imprinted genes, however, this is not the case. The alleles of imprinted genes are epigenetically modified in a parent-of-origin-specific manner and, as a consequence, maternally- and paternally-derived alleles behave differently. Typically one allele is expressed while the other is silent. Although relatively few in number, imprinted genes are the focus of intensive study, as they have important roles in embryonic development. Abnormal expression of imprinted genes results in growth disorders and is implicated in several clinical conditions. Most studies of imprinted genes have been performed in rodents or primates, with limited studies in other mammals such as bovine and opossum. We have recently demonstrated the existence of imprinted genes in the canine, by showing that the canine insulin-like growth factor 2 receptor gene ( IGF2R ) is monoallelically expressed, with predominant expression of the maternally-derived allele and repression of the paternally-inherited allele. Our ultimate goal is to characterize all imprinted genes in the canine, and to understand how they contribute to canine reproduction, development and disease. Such knowledge will be vital for optimizing the success of most reproductive strategies in the canine.     

Attitudes of veterinarians to undergraduate education in genetics and the use of genetics in veterinary occupations

A questionnaire regarding attitudes to undergraduate education in genetics and the subsequent use of that education was sent to 1000 veterinarians registered in New South Wales. Three hundred replies to the questionnaire were received and analysed. No significant difference in the perceived adequacy of courses at the four universities involved in teaching veterinary science was observed. Opinions on adequacy of education in genetics were not affected by age, sex or years since graduation. The major reason cited for lack of adequacy was that undergraduate genetics courses were not practical. Only 17 respondents stated that they were never approached for information on genetics or animal breeding, while 76 were approached more than 20 times annually for information. Eighty-three respondents claimed to deal with more than 20 cases annually that required some knowledge of genetics. The results of the questionnaire highlight the importance of genetics instruction in undergraduate veterinary education. The questionnaire responses also provide insight into how working veterinarians consider that courses in genetics could be improved.     

Genotypic diversity in field isolates of Babesia bovis from cattle with babesiosis after vaccination

Objective To determine whether particular genotypes of Babesia bovis were common to field isolates obtained from cattle properties in Queensland where the B bovis vaccine had apparently failed.
Design A comparative study of polymerase chain reaction genotypes in different populations of B bovis .
Procedure Two polymerase chain reaction assays were applied to analyse DNA extracts of B bovis vaccine (K, T and Dixie strains) and 27 field isolates from 24 properties where disease outbreaks had occurred despite the use of the vaccine. To evaluate the stability of the genotypes identified, 11 of the field isolates were inoculated into experimental cattle that had either been previously vaccinated with T strain or not vaccinated.
Results No particular genotype of B bovis was responsible for the problems observed in previously vaccinated herds. None of the isolates had genotypes identical to the vaccine strains used. No geographic trends among the genotypes were observed. Isolates that originated from the same property also had different genotypes. Blood passage of the 11 field isolates in either previously vaccinated or nonvaccinated cattle did not alter the original genotype.
Conclusion No particular genotypes identified by the Bv80 and BvVA1 polymerase chain reaction assays could be associated with vaccine failures.     

Surgical treatment of osteomyelitis and sequestration of the ilium by a cranial partial hemipelvectomy in an alpaca cria

A 12-week-old female alpaca cria weighing 10 kg presented with a 2-month history of left hindlimb lameness associated with osteomyelitis and sequestration of the shaft and wing of the left ilium. The affected segment of the ilium was surgically removed. Bacteriological culture revealed a small number of mixed aerobic and anaerobic bacteria. The cria recovered well, was discharged from the hospital 8 days after surgery and was paddock sound without complications 8 months later. Osteomyelitis and sequestration of long bones has been reported in alpacas, but further investigation is necessary to define the prevalence and pathogenesis and to develop specific recommendations for prevention and treatment.     

Salmonella Brandenburg — emergence of a variant strain on a sheep farm in the South Island of New Zealand

AIM: To compare the rectal and I/V administration of tramadol in dogs, to assess both its pharmacokinetic properties and absolute bioavailability.

METHODS: After rectal administration via suppositories and I/V injection of tramadol (4 mg/kg), the concentration of tramadol and its main metabolites, O-desmethyl-tramadol (M1), N-desmethyl-tramadol (M2) and N,O-didesmethyl-tramadol (M5), were determined in plasma, using high-performance liquid chromatography (HPLC). A balanced cross-over study was used, involving six male Beagle dogs.

RESULTS: Plasma concentrations after rectal and I/V administration were fitted on the basis of mono- and bi-compartmental models, respectively. Following rectal administration tramadol was detected from 5 minutes up to 10 hours, in lesser amounts than M5 and M2, while M1 was detected in negligible amounts. Following I/V administration tramadol was detected up to 10 hours, M2 and M5 were detected at similar concentrations, and M1 was present at low concentrations. The area under the curve (AUC) of the three metabolites did not differ significantly after either route of administration of tramadol. The absolute bioavailability of tramadol via rectal administration was 10 (SD 4)%.

CONCLUSIONS: After rectal administration of tramadol suppositories, absorption of the active ingredient was rapid, but its metabolism quickly transformed the parent drug to high levels of M2 and M5.

CLINICAL RELEVANCE: In the dog, rectal pharmaceutical formulation of tramadol would have a different pharmacokinetic behaviour than in humans.