A novel mutation of the CLCN1 gene associated with myotonia hereditaria in an Australian cattle dog

BACKGROUND: Heritable myotonia is a genetic muscle disorder characterized by slow relaxation of skeletal muscles. The main clinical signs are skeletal muscle stiffness, especially after vigorous contraction, and muscle hypertrophy. Muscle stiffness may be enhanced by inactivity, and often is relieved by exercise. Myotonia can be inherited in an autosomal dominant or recessive manner (Thomsen- or Becker-type myotonia, respectively). In mice, goats, Miniature Schnauzer dogs, and most affected humans, the disorder is caused by mutations in CLCN1, which encodes the skeletal muscle voltage-gated chloride channel, Cl1C-1. HYPOTHESIS: We hypothesized that an Australian Cattle Dog with generalized muscle stiffness and hypertrophy examined at the Ontario Veterinary College would have a mutation in the CLCN1 gene. ANIMALS: A pure-bred Australian Cattle Dog from Ontario, Canada, was used. METHODS: Based on clinical signs and electromyographic test results, a diagnosis of myotonia hereditaria was made, and a muscle biopsy was collected for genetic analysis. RESULTS: Sequence data obtained from the affected dog confirmed that it was homozygous for a single base insertion in the CLCN1 coding sequence. This mutation would result in a truncated ClC-1 protein being expressed, which, based on molecular evidence from other studies, would result in functionally compromised chloride conduction in the skeletal muscles of the animal. CONCLUSIONS AND CLINICAL IMPORTANCE: To the authors' knowledge, this report describes the Ist case of myotonia in an Australian Cattle Dog and represents the 1st non-Schnauzer canine myotonia to be genetically characterized. In addition, we developed a polymerase chain reaction-based genetic screen to detect heterozygotes with this mutation in the at-large Australian Cattle Dog population.     

Species diversity and acquisition of gastrointestinal parasites in calves aged 0-13 months in periurban livestock production in Mali

Post-mortem inspections on 51 calves were conducted to investigate acquisition and spectrum of gastrointestinal parasites in young calves in periurban livestock production in Mali. Generalized linear models with herd as a repeated effect were used to test the influence of management, age and season of birth on parasite numbers and diversity. Parasite number and burden increased with age. In the age class 4-13 months animals carried already up to eight different gastrointestinal parasite species. Parasite spectrum found included 11 nematodes, 3 cestodes and 1 protozoan parasite. The most frequent parasite species found were Haemonchus placei (age class 0-1 month: 7%, 1-4 months: 38%, 4-13 months: 69%), Cooperia pectinata (0%, 33% and 44%) and C. punctata (0%, 33% and 38%). Calves born during the rainy season had higher parasite burden and species diversity than calves born during the dry season. Calves kept under modernised management excreted more Strongyloides papillosus eggs than calves kept under traditional management. Calves acquired most of the parasites occurring in adult bovines in West Africa within their first year of life.     

TRANS-SPLENIC PORTAL SCINTIGRAPHY IN NORMAL DOGS

The purpose of this study was to (1) establish a technique for ultrasound-guided trans-splenic portal scintigraphy (TSPS) using 99mTcO4(-), (2) evaluate portal vein morphology, (3) compare the radiation exposures for TSPS vs. per-rectal portal scintigraphy (PRPS), and (4) compare the quality of numerical data from the TSPS vs. PRPS. Eight juvenile dogs underwent PRPS and TSPS (minimum of 48h between studies) after initial screening tests. PRPS was done according to established protocol using 425 +/- 36MBq (mean +/- SD) of 99mTcO4(-). TSPS was done with the dogs in right lateral recumbency over the gamma camera. 99mTcO4(-) (57 +/- 13.9 MBq) was injected into the spleen 1-2s following initiation of the dynamic acquisition. The frame rate was 4 frames/s for 5 min. There was significantly lower radioactivity of 99mTcO4(-) given and significantly higher total counts recorded in the liver and heart during the TSPS compared with PRPS. The total counts for the TSPS and PRPS were 7120 +/- 4386 and 830 +/- 523, respectively. Percent absorption from the spleen was 52.5 +/- 19.1% compared with 9.2 +/- 5.7% for the colon. Calculated transit time for the TSPS studies was 7 +/- 2.3s. In TSPS studies, the splenic and portal veins were clearly identified. Radiation exposure levels of the dogs were significantly lower following TSPS than after PRPS. TSPS appears superior to PRPS as a method to image the portal venous system representing a valid alternative diagnostic test for animals with suspected portosystemic shunts.     

Synovial fluid changes in induced infectious arthritis in calves

The objective was to develop an experimental model of septic arthritis in calves and to evaluate the effect of treatment on cytologic and bacteriologic variables of synovial fluid. The right tarsus of 7 healthy Holstein bull calves were inoculated with 10(8) colony-forming units of viable Escherichia coli of a pap-positive strain (day 1). On day 2, joint lavage was performed and antibiotic treatment was instituted. Cytologic examinations, bacterial cultures, and pap factor determinations by polymerase chain reaction (PCR) were performed on synovial fluid samples that were collected daily until day 4, then every 4 days until day 24. Results of physical examination, the severity of lameness, and swelling were recorded. Clinical signs of septic arthritis appeared on day 2 and persisted until day 9 for all calves. Bacterial cultures from all calves were positive for E. coli on day 2, and remained positive until day 3 for 1 calf and until day 4 for 5 calves. In addition, PCR results were positive for all calves, with 6 positive through day 3 and 1 positive through day 4, after which a positive result was again obtained on day 24. Synovial fluid neutrophil counts and white blood cell counts were significantly increased on days 2-4; however, synovial total protein concentrations were increased (P < .05) throughout the experiment in comparison to day 1. Results of all bacterial cultures were negative on day 8, although clinicopathologic signs of inflammation persisted until day 20. This model successfully induced acute septic arthritis in calves. Rapid recovery occurred within 1 week when an appropriate treatment was instituted early in the course of the disease.     

Recovery from rocuronium-induced neuromuscular block was longer in the larynx than in the pelvic limb of anesthetized dogs

Objective

To determine if neuromuscular monitoring at the pelvic limb accurately reflects neuromuscular function in the larynx after administration of rocuronium in anesthetized dogs.

COMPUTED TOMOGRAPHIC FINDINGS OF DOGS WITH CUBITAL JOINT LAMENESS

The purpose of this study was to identify the incidence of abnormal computed tomography (CT) findings in dogs with lameness of one or both elbows. CT examinations of 102 elbows in 51 dogs were reviewed individually and by group consensus by 3 examiners and graded for various abnormalities. Frequently encountered abnormalities included abnormal shape and sclerosis of the medial coronoid process of the ulna, irregularity of the radial incisure of the ulna, and ulnar trochlear notch sclerosis. Other abnormalities included distinct/separate or fissure/in situ fragmentation of the medial coronoid; lucency of the radial incisure; ununited anconeal process; sclerosis, lucency, or flattening of the medial aspect of the humeral condyle; osteophyte formation; and joint incongruity. In conclusion, CT of the canine cubital joint is useful in identification of various lesions beyond simple fragmentation of the medial coronoid process of the ulna.