Nemaline myopathy (NM) is a congenital muscle disorder associated with muscle weakness, hypotonia, and rod bodies in the skeletal muscle fibers. Mutations in 10 genes have been implicated in human NM, but spontaneous cases in dogs have not been genetically characterized. We identified a novel recessive myopathy in a family of line-bred American bulldogs (ABDs); rod bodies in muscle biopsies established this as NM. Using SNP profiles from the nuclear family, we evaluated inheritance patterns at candidate loci and prioritized TNNT1 and NEB for further investigation. Whole exome sequencing of the dam, two affected littermates, and an unaffected littermate revealed a nonsense mutation in NEB (g.52734272 C>A, S8042X). Whole tissue gel electrophoresis and western blots confirmed a lack of full-length NEB in affected tissues, suggesting nonsense-mediated decay. The pathogenic variant was absent from 120 dogs of 24 other breeds and 100 unrelated ABDs, suggesting that it occurred recently and may be private to the family. This study presents the first molecularly characterized large animal model of NM, which could provide new opportunities for therapeutic approaches.

Background: Many studies of epilepsy in veterinary medicine use subjective data (eg, caregiver-derived histories) to determine seizure frequency. Conversely, in people, objective data from electroencephalography (EEG) are mainly used to diagnose epilepsy, measure seizure frequency and evaluate efficacy of antiseizure drugs. These EEG data minimize the possibility of the underreporting of seizures, a known phenomenon in human epileptology.Objective: To evaluate the correlation between reported seizure frequency and EEG frequency of ictal paroxysmal discharges (PDs) and to determine whether seizure underreporting phenomenon exists in veterinary epileptology.Animals: Thirty-three ambulatory video-EEG recordings in dogs showing ≥1 ictal PD, excluding dogs with status epilepticus.Methods: Retrospective observational study. Ictal PDs were counted manually over the entire recording to obtain the frequency of EEG seizures. Caregiver-reported seizure frequency from the medical record was categorized into weekly, daily, hourly, and per minute seizure groupings. The Spearman rank test was used for correlation analysis.Results: The coefficient value (r s ) comparing reported seizure to EEG-confirmed ictal PD frequencies was 0.39 (95% confidence interval [CI] = 0.048-0.64, P = .03). Other r s values comparing history against various seizure types were: 0.36 for motor seizures and 0.37 for nonmotor (absence) seizures.Conclusions and Clinical Importance: A weak correlation was found between the frequency of reported seizures from caregivers (subjective data) and ictal PDs on EEG (objective data). Subjective data may not be reliable enough to determine true seizure frequency given the discrepancy with EEG-confirmed seizure frequency. Confirmation of the seizure underreporting phenomenon in dogs by prospective study should be carried out.

BackgroundCanine ventral atlantoaxial (AA) stabilization is most commonly performed in very small dogs and is technically challenging due to extremely narrow bone corridors. Multiple implantation sites have been suggested but detailed anatomical studies investigating these sites are lacking and therefore current surgical guidelines are based upon approximate anatomical landmarks. In order to study AA optimal safe implantation corridors (OSICs), we developed a method based on computed tomography (CT) and semi-automated three-dimensional (3D) mathematical modelling using OsiriX™ and Microsoft®Excel software. The objectives of this study were 1- to provide a detailed description of the bone corridor analysis method and 2- to assess the reproducibility of the method. CT images of the craniocervical junction were prospectively obtained in 27 dogs and our method of OSIC analysis was applied in all dogs. For each dog, 13 optimal implant sites were simulated via geometrical simplification of the bone corridors. Each implant 3D position was then defined with respect to anatomical axes using 2 projected angles (ProjA). The safety margins around each implant were also estimated with angles (SafA) measured in 4 orthogonal directions. A sample of 12 simulated implants was randomly selected and each mathematically calculated angle was compared to direct measurements obtained within OsiriX™ from 2 observers repeated twice. The landmarks simulating anatomical axes were also positioned 4 times to determine their effect on ProjA reproducibility.ResultsOsiriX could be used successfully to simulate optimal implant positions in all cases. There was excellent agreement between the calculated and measured values for both ProjA (ρc = 0.9986) and SafA (ρc = 0.9996). Absolute differences between calculated and measured values were respectively [ProjA = 0.44 ± 0.53°; SafA = 0.27 ± 0.25°] and [ProjA = 0.26 ± 0.21°; SafA = 0.18 ± 0.18°] for each observer. The 95 % tolerance interval comparing ProjA obtained with 4 different sets of anatomical axis landmarks was [−1.62°, 1.61°] which was considered appropriate for clinical use.ConclusionsA new method for determination of optimal implant placement is provided. Semi-automated calculation of optimal implant 3D positions could be further developed to facilitate preoperative planning and to generate large descriptive anatomical datasets.Electronic supplementary materialThe online version of this article (doi:10.1186/s12917-016-0824-3) contains supplementary material, which is available to authorized users.

A minimally invasive method for delivering injectable therapeutic agents would be desirable for the treatment of intervertebral disc disease in dogs. The purpose of this study was to compare computed tomography (CT), ultrasonography (US), and fluoroscopy modalities for guiding percutaneous injection into canine intervertebral discs. Intervertebral discs of 14 dog cadavers were injected with a gelified ethanol therapeutic agent. Successful injectate placement and injectate leakage were determined based on necropsy inspection of discs. Injection into the nucleus pulposus was successful in 55 of 78 (71%) of all injected discs. Injections guided using CT and fluoroscopy were significantly more successful than US-guided injections. Odds of successful injection without leakage were greater for CT vs. US (P = 0.0026) but there was no significant difference between CT and fluoroscopy (P = 0.0620). Injection success rates did not differ among vertebral sites or dog cadavers of varying weights. Forty-nine (63%) of injection sites had injectate leakage outside the disc and 10 of these involved structures within the vertebral canal. The highest rate of injection success with the least amount of leakage was achieved with CT guidance. Findings indicated that CT, fluoroscopy, and US are feasible modalities for guiding percutaneous injection of a gelified ethanol therapeutic agent into the canine intervertebral disc, with moderate to high success rates for different regions of the spine. However, a moderately high rate of injectate leakage occurred outside of the disc and this should be taken into consideration for future safety and efficacy studies.

Case summaryA 10-year-old neutered male domestic shorthair cat presented for evaluation of acute onset of paraplegia with loss of nociception and thoracolumbar spine hyperesthesia and no history of trauma. Activated partial thromboplastin time (aPTT) was markedly prolonged, and specific coagulation factor testing revealed a factor IX level of 4% of normal activity, confirming the presence of mild hemophilia B. Prior abnormal bleeding had occurred at the time of castration as a kitten, as well as with laceration to a toe. Advanced imaging, including computed tomography (CT) and magnetic resonance imaging (MRI) of the thoracolumbar spine, confirmed the presence of multifocal intradural and intramedullary spinal cord hemorrhage through demonstration of focal ring enhancement on CT and multifocal areas of signal void on gradient echo T2* images on MRI. Despite factor IX supplementation through the use of fresh frozen plasma transfusions and normalization of the aPTT time, the cat’s neurological status did not improve. Owing to repeated urinary tract infections, with increasing resistance to antibiotic therapy, the cat was ultimately euthanized. Post-mortem examination showed no evidence of another underlying primary pathology for the hematomyelia.Relevance and novel informationTo our knowledge, this case demonstrates the first reported occurrence of spontaneous hematomyelia secondary to hemophilia B in a cat.

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The inner ear contains endolymph and perilymph. The second is comparable and in continuity with the cerebrospinal fluid (CSF) so it is expected to suppress in fluid‐attenuated inversion recovery (FLAIR) magnetic resonance imaging (MRI) if normal. Even though inner ear FLAIR abnormalities have been extensively described in humans with inner ear disease, its diagnostic value in dogs is yet to be proven. The goal of this retrospective cohort study was to investigate the diagnostic utility of FLAIR MRI in dogs with vestibular disease. A review of medical records identified 101 dogs that had brain MRI performed because of vestibular signs. Based on the final diagnosis, patients were allocated to three groups: otitis media/interna, idiopathic vestibular disease, and central vestibular disease. Additionally, a control group (n = 73) included dogs with normal MRI and without vestibular signs. Inner ears were delineated using a region of interest, and signal intensity was measured in FLAIR and T2‐weighted images. The percentages of suppression in FLAIR were calculated and compared between affected and unaffected sides of each individual and between groups using a general linear mixed model. Correlation between suppression and CSF cell count and protein concentration was assessed. Affected inner ears in dogs with otitis media/interna had decreased suppression in FLAIR compared to the unaffected side (P < .001), and all other groups (P < .01). No significant correlation was detected between CSF results and suppression. These results show the diagnostic value of FLAIR in otitis media/interna due to lack of suppression in the affected inner ear.

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