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An X-linked muscular dystrophy, with deficiency of full-length dystrophin and expression of a low molecular weight dystrophin-related protein, has been described in Japanese Spitz dogs. The aim of this study was to identify the causative mutation and develop a specific test to identify affected cases and carrier animals. Gene expression studies in skeletal muscle of an affected animal indicated aberrant expression of the Duchenne muscular dystrophy (dystrophin) gene and an anomaly in intron 19 of the gene. Genome-walking experiments revealed an inversion that interrupts two genes on the X chromosome, the Duchenne muscular dystrophy gene and the retinitis pigmentosa GTPase regulator gene. All clinically affected dogs and obligate carriers that were tested had the mutant chromosome, and it is concluded that the inversion is the causative mutation for X-linked muscular dystrophy in the Japanese Spitz breed. A PCR assay that amplifies mutant and wild-type alleles was developed and proved capable of identifying affected and carrier individuals. Unexpectedly, a 7-year-old male animal, which had not previously come to clinical attention, was shown to possess the mutant allele and to have a relatively mild form of the disease. This observation indicates phenotypic heterogeneity in Japanese Spitz muscular dystrophy, a feature described previously in humans and Golden Retrievers. With the availability of a simple, fast and accurate test for Japanese Spitz muscular dystrophy, detection of carrier animals and selected breeding should help eliminate the mutation from the breed., (© 2015 Stichting International Foundation for Animal Genetics.)

Objective: To determine the effect of Hct on blood glucose readings of dogs obtained by use of 2 point-of-care (POC) blood glucometers and a laboratory analyzer., Animals: 184 dogs, including 139 Greyhounds., Procedures: Venous blood samples collected from 184 dogs with a range of Hcts (measured in EDTA-anticoagulated blood) were immediately analyzed with a handheld glucometer specifically developed for veterinary use and a glucometer developed for use in humans. The remainder of each blood sample was placed in fluoride oxalate tubes, and plasma glucose concentration was measured with a laboratory analyzer. Agreement between results for the POC glucometers and laboratory analyzer and effect of Hct on glucometer accuracy was assessed via regression analysis., Results: Significant differences were detected between results of the glucometers and the reference laboratory analyzer. The Hct affected the correlation between results for the glucometers and the laboratory analyzer. Deviations of the glucometers from the reference interval varied with Hct. The glucometer for veterinary use more closely correlated with the glucose concentration when Hct was within or above its reference interval. The glucometer for use in humans more closely approximated laboratory reference glucose concentrations in anemic dogs., Conclusions and Clinical Relevance: Hct had a relevant impact on the correlation between whole blood and plasma glucose concentrations in dogs. Significant variations between results obtained with the 2 glucometers could be critical when interpreting blood glucose measurements or selecting a POC glucometer for an intensive care setting and precise glycemic control in critically ill dogs.

Total thyroxine (T(4)) concentrations were below the non-breed-specific reference range in 42 of 46 healthy young greyhounds (91.3 per cent) and 16 (34.8 per cent) were at or below the limit of detection of the assay. Free T(4) concentrations were below the standard reference interval in 20.5 per cent of the animals and 13 per cent were at or below the limit of detection of the assay. In contrast, all the dogs' total tri-iodothyronine concentrations were within or above the non-breed-specific reference range and 67 per cent were within the upper half. All the dogs' thyroid stimulating hormone concentrations were within the non-breed-specific reference range. The results show that young greyhounds have markedly lower total and free T(4) concentrations than other breeds, and neither analyte can reliably be used to investigate the hypothyroidism in this breed as values were found below the limit of detection of each respective assay.

Background: Greyhound dogs have numerous clinicopathologic differences compared with other dog breeds, most notably in their hematologic profiles. The hematologic differences are likely related to breed; however, the influence of other factors, including age, sex, and training, has not been fully determined., Objectives: The aim of this study was to assess hematologic values in young, healthy, pretraining Greyhounds and to determine the effects of age and sex on these findings., Methods: Jugular venous EDTA-anticoagulated blood samples were collected from 43 healthy, pretraining Greyhounds between 5 and 13 months of age. Samples were analyzed within 24 hours of collection on an Abbott CELL-DYN 3500R hematology analyzer. Mean hematologic results for different age groups, and correlation with age and sex were determined for each analyte. Results were compared with adult canine, nonbreed-specific reference intervals., Results: From the age of 9 to 10 months, Greyhounds had higher HCT, hemoglobin concentration, and RBC counts compared with adult canine reference intervals. Younger Greyhounds (5-6 months) had values comparable with reference intervals. Mean total WBC, neutrophil, lymphocyte, and platelet counts tended to be toward the lower end or below the reference intervals. HCT, hemoglobin concentration, and RBC counts were correlated positively with age, and platelet count was correlated negatively with age. No differences were found based on sex., Conclusions: These results confirm that significant hematologic differences exist in pretraining Greyhounds by 9 to 10 months of age, when compared with adult canine, nonbreed-specific reference intervals; however, these differences are less marked in Greyhounds 5 to 6 months old. Given these findings, it is unlikely that factors such as training or racing are responsible for differences in hematologic values between adult Greyhounds and other breeds.

Objectives: To determine the ionised calcium concentration following aerobic collection of blood and to compare ionised calcium concentration and pH of heparinised whole blood and plasma at 48 hours following collection under three different storage conditions to assess if ionised calcium concentration can be measured retrospectively., Methods: Blood was collected from 17 dogs for analysis of ionised calcium concentration and pH using a Rapidpoint 400 (Bayer) blood gas analyser. Blood was collected into a commercial preheparinised syringe and into a plain syringe, with subsequent transfer to a commercially available heparinised sample tube. Samples were analysed within 10 minutes, and the remainder was divided for storage. One aliquot was set-aside at room temperature for 48 hours, and the other was immediately centrifuged and the plasma divided for storage at room temperature and at 4 degrees C for 48 hours each. In all samples, ionised calcium concentration and pH were measured again at 48 hours after storage., Results: There was no significant difference in ionised calcium concentration or pH between anaerobically and aerobically collected heparinised whole blood analysed within 10 minutes of collection. At 48 hours, ionised calcium concentrations had decreased under all storage conditions irrespective of the direction of pH change., Clinical Significance: Ionised calcium concentration can be measured in aerobically collected samples within 10 minutes and at 48 hours after collection under the conditions described.

Background The aetiology of insulin resistance ( IR) in naturally occurring canine hypothyroidism is poorly understood and likely multifactorial. Excess secretion of growth hormone ( GH) by transdifferentiated pituitary cells may contribute to IR in some hypothyroid dogs, but although this has been demonstrated in experimental studies, it has not yet been documented in clinical cases. Case report A 4-year-old male entire Samoyed presented with an 8-month history of pedal hyperkeratosis and shifting lameness, which had been unresponsive to zinc supplementation, antibiotics and glucocorticoid therapy. The dog also exhibited exercise intolerance and polydipsia of 12 and 2 months duration, respectively. On physical examination, obesity, poor coat condition, widened interdental spaces and mild respiratory stridor were noted. Initial laboratory test results revealed concurrent hypothyroidism and diabetes mellitus ( DM). Further investigations showed IR, GH excess and a paradoxical increase of GH following stimulation with thyrotropin-releasing hormone. Conclusions To the authors' knowledge, this is the first reported case that suggests that GH alterations may have clinical significance in naturally occurring hypothyroidism. Among other factors, hypothyroidism-induced GH excess should be considered as a possible cause of IR in patients suffering from hypothyroidism and concurrent DM. In such cases, DM may reverse with treatment of hypothyroidism, as was documented in this case. [ABSTRACT FROM AUTHOR]