Ultrasonographic measurement of gallbladder wall thickness in fasted dogs without signs of hepatobiliary disease.

BACKGROUND: Ultrasound-determined gallbladder wall thickness is widely used to aid in the diagnosis of gallbladder disease, but no reference values supported by published measurement data are available in dogs. HYPOTHESIS/OBJECTIVE: Establish normal thickness of the gallbladder wall in dogs. ANIMALS: Fifty-three dogs presented to a referral hospital and required abdominal ultrasound examination for reasons unrelated to primary hepatobiliary disease. METHODS: Cross-sectional observational study recruiting dogs requiring abdominal ultrasound examination. A standard sequence of gallbladder wall images was recorded for later review. Inclusion criteria were normal ultrasonographic hepatobiliary, pancreatic, and small intestinal findings. Exclusion was determined by 2 European College of Veterinary Internal Medicine (ECVIM)-certified veterinary internists blinded to gallbladder wall thickness data. Dogs were excluded if they had inadequate medical records, a previous history of hepatobiliary, gastrointestinal, or pancreatic disease likely to impact the biliary system (eg, chronic vomiting, nausea, jaundice, diarrhea), unexplained increases in liver enzyme activities, hypoalbuminemia, or ascites. Gallbladder wall thickness was determined by 2 European College of Veterinary Diagnostic Imaging (ECVDI)-certified veterinary radiologists working together to generate a consensus for each dog. The final output was the maximum normal wall thickness for this population of dogs. RESULTS: The upper limit for gallbladder wall thickness in 53 fasted (8 hours) dogs <40 kg was 1.30 mm (90% confidence interval, 1.19-1.41). CONCLUSIONS AND CLINICAL IMPORTANCE: Normal gallbladder wall thickness in dogs is lower than previously reported. Additional studies are required to determine potential effects of body weight and the optimal cut-off to distinguish between healthy and diseased gallbladders.

The comparative performance of a custom Canine NanoString® panel on FFPE and snap frozen liver biopsies.

Formalin-Fixed Paraffin Embedded (FFPE) biopsies would provide a critical mass of cases to allow investigation of canine liver disease, however their use is often limited by challenges typically associated with transcriptomic analysis. This study evaluates the capability of NanoString® to measure the expression of a broad panel of genes in FFPE liver samples. RNA was isolated from matched histopathologically normal liver samples using FFPE (n = 6) and snap frozen in liquid nitrogen (n = 6) and measured using a custom NanoString® panel. Out of the 40 targets on the panel, 27 and 23 targets were above threshold for non-diseased snap frozen and FFPE tissue respectively. The binding density and total counts were significantly reduced in the FFPE samples relative to the snap frozen samples (p = 0.005, p = 0.01, respectively), confirming a reduction in sensitivity. The concordance between the snap frozen and FFPE samples was high, with correlations (R) ranging between 0.88 and 0.99 between the paired samples. An additional 14 immune-related targets, undetectable the non-diseased FFPE liver, were above threshold when the technique was applied to a series of diseased samples, further supporting their inclusion on this panel. This use of NanoString® based analysis opens up huge opportunity for retrospective evaluation of gene signatures in larger caseloads through harnessing the capacity of archived FFPE samples This information used alongside clinical and histological data will not only afford a way to explore disease etiopathogenesis, it may also offer insight into sub-types of liver disease in dogs, which cannot be discerned using more traditional diagnostic methods.

Diagnosis of canine spontaneous hypoadrenocorticism.

Hypoadrenocorticism is characterized by a reduction in mineralocorticoid and/or glucocorticoid production by the adrenal glands. Several subtypes have been described with different clinical and clinicopathological consequences. Most affected dogs have vague and non-specific signs that precede an eventual life-threatening crisis. This review aims to appraise classification, the available data on epidemiology and the clinical and laboratory features of naturally occurring canine hypoadrenocorticism.

Canine hypoadrenocorticism is a relatively uncommon endocrine disease that can present with a wide variety of clinical signs resulting from cortisol or aldosterone deficiency or both. Hypoadrenocorticism should be considered in all dogs with severe illness and typical electrolyte abnormalities but also in those with waxing and waning clinical signs. Multiple clinical and laboratory features are suggestive of the disease and should prompt evaluation of adrenal function. The ACTH stimulation test is the best test for diagnosing hypoadrenocorticism but, in those cases without the typical presentation, evaluation of aldosterone secretory capacity and endogenous ACTH concentrations should be performed to distinguish primary from secondary disease. In this review we discuss the pathophysiology of the disease, the clinical signs and laboratory features that should raise suspicion of hypoadrenocorticism and the performance of the different diagnostic tests.

Free thyroxine measurement by analogue immunoassay and equilibrium dialysis in dogs with non-thyroidal illness.

OBJECTIVES: Measurement of free T4 by analogue immunoassay (fT4a) is popular but its ability to differentiate hypothyroidism from non-thyroidal illness (NTI) is unclear. The aims were to assess fT4a concentrations in dogs with NTI and to explore diagnostic agreement with total T4 and free T4 measured by equilibrium dialysis (fT4d). METHODS: fT4a was measured in dogs classified with mild, moderate and severe NTI. Total T4 and fT4d were measured in a subgroup of these dogs. RESULTS: 146 dogs were included of which 84, 35 and 27 had mild, moderate and severe NTI, respectively. Median (range) fT4a concentrations (pmol/L) were significantly lower (P = 0.023 and P < 0.001) in dogs with severe (3.86 (3.86-23.60)) compared with moderate (11.10 (3.86-34.70)) and mild (15.25 (3.86-48.60)) NTI. Overall, 49 (33.6% [95% CI, 26.4-41.6]) dogs had low fT4a concentration. All thyroid hormones were measured in 74 dogs. Agreement was substantial between total T4 and fT4a (κ=0.79 [95% CI, 0.65-0.92]) and fT4a and fT4d (κ =0.63 [95% CI, 0.47-0.79]) but moderate between total T4 and fT4d (κ=0.49 [95% CI, 0.32-0.66]). Of 42 dogs with low total T4 concentration, five (11.9% [95% CI, 5.19-24.99]) and 18 (42.9% [95% CI, 29.12-57.80]) had fT4a and fT4d within reference interval, respectively. CONCLUSIONS AND CLINICAL IMPORTANCE: fT4a and fT4d cannot be used interchangeably. Measurement of fT4a provides limited further diagnostic information over measurement of total T4 in dogs with NTI. This study raises concerns regarding the ability of fT4a to differentiate NTI from hypothyroidism in dogs with low total T4 concentrations.

Insulins for the long term management of diabetes mellitus in dogs: a review.

The year 2021 marked the centenary of the isolation of a therapeutic form of insulin and its successful use in dogs. This was a landmark moment that subsequently and rapidly led to the commercial manufacture of insulin for use in humans. The impact of insulin was almost miraculous as those destined to die from their diabetes mellitus returned to life. Over the past 100 years, insulin formulations have been modified to attempt to provide a predictable and prolonged duration of action while avoiding the development of hypoglycaemia. This has led to an ever-growing variety of insulin types in human medicine, many of which have subsequently been used in dogs. The purpose of this review article is to provide an overview of available insulin types and their application to the chronic management of canine diabetes mellitus.

A Preliminary Study of the Effect of Hyperadrenocorticism on Calcium and Phosphate Concentrations, Parathyroid Hormone and Markers of Bone Turnover in Dogs.

Reports on the effects of hyperadrenocorticism (HAC) on bone turnover in dogs are largely confined to radiographic studies. The aim of this study was to more accurately assess bone turnover in dogs with HAC by measuring circulating total and ionized calcium and phosphate concentrations, both intact and whole parathyroid hormone (PTH) concentrations and markers of both osteoblastic (osteocalcin) and osteoclastic [carboxyterminal cross-linked telopeptide of type 1 collagen (ICTP) and urine aminoterminal telopeptide of type 1 collagen (NTX) activity]. Dogs with HAC and a control group were prospectively enrolled for comparison. Results from 49 dogs with HAC were compared with 39 dogs from a hospital control population. Plasma intact and whole PTH concentrations were determined using a human immunoradiometric assay. Serum osteocalcin and NTX concentrations were measured using human enzyme linked immunosorbent assays. Serum ICTP concentration was measured using a human radioimmunoassay. Total calcium concentrations in dogs with HAC (2.67 ± 0.25 mmol/L) were not significantly different than in the control group (2.67 ± 0.14 mmol/L). By contrast, phosphate concentrations were significantly (P = 0.0143) higher in dogs with HAC (1.46 ± 0.30 mmol/L) compared to the control group (1.28 ± 0.33 mmol/L). The median intact PTH concentration in HAC dogs was 9.25 (range, 1.34-95.45) pmol/L, which was significantly (P < 0.0001) higher than in the control group [median, 3.88 (range, 2.01-10.31) pmol/L]. Whole PTH concentrations were also significantly (P < 0.0001) higher in the HAC group [median, 4.61 (range, 0.56-125.16) pmol/L] compared to the control group [median, 1.83 (range, 0.88-6.81) pmol/L]. Serum osteocalcin and urine NTX concentrations were not significantly different between the two groups of dogs. The median ICTP concentration in dogs with HAC was 2.98 (range, 1.15-6.62) ng/mL which was significantly (P < 0.0001) lower than in the control dogs [median, 7.30 (range, 3.68-21.25) ng/mL]. Both whole and intact PTH concentrations are increased in dogs with HAC compared to a hospital control population. This does not however appear to be associated with a decrease in bone formation (as assessed by osteocalcin) or an increase in bone resorption (as assessed by ICTP and urine NTX).

Polyneuropathy in Young Siberian Huskies Caused by Degenerative and Inflammatory Diseases.

Polyneuropathy is defined as the simultaneous dysfunction of several peripheral nerves. In dogs, a number of breeds are predisposed to a variety of immune-mediated and/or degenerative inherited forms of polyneuropathy, with laryngeal paralysis and/or megaesophagus as important clinical features of many of these conditions. This case series describes degenerative and inflammatory polyneuropathies in 7 young Siberian huskies that were categorized based on clinicopathological characteristics as follows: (1) slowly progressive laryngeal paralysis and megaesophagus caused by primary axonal degeneration with large fiber loss (n = 2); (2) slowly progressive polyneuropathy without megaesophagus or laryngeal paralysis caused by primary axonal degeneration with large fiber loss (n = 2); (3) acute inflammatory demyelinating neuropathy causing sensory, motor and autonomic nerve deficits (n = 2); and (4) ganglioradiculitis (sensory neuronopathy; n = 1). Based on the predominantly young age at onset, slow progression, relatedness of affected dogs, and clinical and pathological similarities with inherited neuropathies reported in other dog breeds, a hereditary basis for the degenerative polyneuropathies in Siberian huskies is suspected. However, 5 different mutations in 3 genes known to cause polyneuropathy in other dog breeds (NDRG1, ARHGEF10, or RAB3GAP1) were not detected in the affected Siberian huskies suggesting that more genetic variants remain to be identified. This study highlights the varied underlying lesions of polyneuropathies in young Siberian huskies.

Investigation of interference from synthetic colloids on the performance of a canine neutrophil gelatinase-associated lipocalin immunoassay.

BACKGROUND: Synthetic colloid solutions, administered by rapid infusion to volume-depleted dogs, might be present in high concentrations in subsequent urine samples. The potential for these solutions to affect the performance of ELISA measurements due to sample matrix effects when studying kidney injury biomarkers requires investigation. OBJECTIVE: We aimed to investigate two different synthetic colloid solutions, 4% succinylated bovine gelatin (GEL) and 6% hydroxyethyl starch (HES), for potential interferences with a commercially available canine neutrophil gelatinase-associated lipocalin (NGAL) ELISA. METHODS: Assay interference was assessed by measuring the linearity of NGAL concentrations measured using a canine NGAL ELISA after serial dilution of a canine pooled urine sample with an assay diluent, GEL, or HES. RESULTS: NGAL recovery from urine specimens containing up to 75% HES and up to 62.5% GEL was within acceptable limits (80%-120%). NGAL recovery from the urine specimen containing 75% GEL was poor (76%). Linear regression analysis demonstrated excellent linearity under dilution when a canine urine sample was diluted with the assay diluent, GEL, or HES. CONCLUSIONS: The presence of large amounts (>62.5%) of GEL in canine urine samples could cause negative interference in the performance of the NGAL ELISA investigated.

Evaluation of red blood cell distribution width in dogs with various illnesses.

In humans, increased red blood cell distribution width (RDW) values are associated with higher morbidity and mortality in a variety of pathological processes. The main objective of this study was to evaluate RDW in dogs with a diverse range of pathologies. Clinical data from 276 dogs were retrospectively evaluated. Significantly higher RDW values were found in dogs with primary immune-mediated hemolytic anemia (P < 0.0001), immune-mediated thrombocytopenia (P < 0.0004), hyperadrenocorticism (P < 0.0001), hypothyroidism (P = 0.0220), hepatic vascular anomaly (P < 0.0001), pneumonia (P < 0.0001), chronic kidney disease (P = 0.0005), multi-centric lymphoma (P = 0.0002), and myxomatous mitral valve degeneration (P = 0.0032). However, there was extensive overlap with the values from healthy dogs, limiting the diagnostic value of RDW in this setting. Although RDW may have a role as a potential prognostic indicator, further studies would be necessary to address this.

Évaluation de l'indice de distribution des globules rouges chez des chiens avec différentes maladies. Chez les humains, une augmentation des valeurs de l'indice de distribution des globules rouges (RDW) est associée avec une plus grande morbidité et mortalité dans une variété de processus pathologiques. L'objectif principal de la présente étude était d'évaluer la RDW chez des chiens avec une variété de pathologies. Les données cliniques de 276 chiens ont été rétrospectivement évaluées. Des valeurs significativement plus élevées de RDW ont été trouvées chez des chiens avec une anémie hémolytique primaire à médiation immunitaire (P < 0,0001), une thrombocytopénie à médiation immunitaire (P < 0,0004), de l'hyperadrénocorticisme (P < 0,0001), de l'hypothyroïdisme (P < 0,0220), une anomalie vasculaire hépatique (P < 0,0001), une pneumonie (P < 0,0001), une maladie rénale chronique (P = 0,0005), un lymphome multicentrique (P = 0,0002), et une dégénérescence myxomateuse de la valvule mitrale (P = 0,0032). Toutefois, il y avait un chevauchement important avec les valeurs provenant de chiens en santé, limitant ainsi la valeur diagnostique de RDW dans ce contexte. Bien que le RDW peut avoir un rôle d'indicateur potentiel de pronostic, des études supplémentaires seraient nécessaires pour y répondre.(Traduit par Dr Serge Messier).

Diagnosis of spontaneous hyperadrenocorticism in dogs. Part 2: Adrenal function testing and differentiating tests.

Hyperadrenocorticism is a relatively common endocrine disorder in dogs that has been extensively described. However, its diagnosis remains challenging because there is no true reference standard test, and a myriad factors can affect the diagnostic performance of the commonly used adrenal function tests. Ultimately, the diagnosis is based on a combination of signalment, history and clinical findings, and a variety of diagnostic test results. The second part of this review aims to appraise available data on diagnostic performance of adrenal function tests in naturally occurring canine hyperadrenocorticism.

Diagnosis of spontaneous hyperadrenocorticism in dogs. Part 1: Pathophysiology, aetiology, clinical and clinicopathological features.

Hyperadrenocorticism is a relatively common endocrine disorder in dogs. It occurs as a result of a functional pituitary or adrenal tumour, although other causes have been rarely reported. Canine hyperadrenocorticism has been extensively described but diagnosing this disease remains challenging. Few studies have investigated the clinical and clinicopathological features helpful in differentiating dogs with hyperadrenocorticism from dogs in which the disease is suspected but eventually excluded. Ultimately the diagnosis is based on a combination of multiple pieces of information emanating from the signalment, history, clinical findings, and a variety of diagnostic tests. The first part of this review aims to critically appraise the available data on epidemiology, clinical and laboratory features of naturally occurring canine hyperadrenocorticism.

Non-functional thyroid cystadenoma in three boxer dogs.

BACKGROUND: Thyroid neoplasia is a common endocrine neoplasm in dogs. The boxer is one of the reported breeds predisposed to malignant thyroid neoplasia. However, the association between thyroid neoplasia, malignancy and breed should be considered with caution. CASES PRESENTATION: This article describes the presentation, clinical pathological findings, computed tomographic (CT) imaging findings and histopathological features of benign cystic thyroid tumour (cystadenoma) diagnosed in three boxers. These three dogs were presented for investigation of unilateral (n = 2) or bilateral (n = 1) cervical masses with no associated clinical signs of thyroid dysfunction. In each case, post-contrast CT scan identified a large, lateralised, non-invasive, well-defined homogeneous cystic structure with a hyperattenuating contrast-enhancing capsule of suspected thyroid origin displacing the surrounding cervical tissues. Ultrasound-guided fine needle aspiration of the cysts yielded fluid with a high thyroxine concentration in each case. Histopathology was consistent with thyroid cystadenoma in all cases. One dog was concurrently diagnosed with oral melanoma and euthanased. Two dogs underwent surgical excision with one lost to follow-up after 36 months and the other euthanased after 16 months following diagnosis of mast cell tumour. CONCLUSIONS: To the authors' knowledge, this is the first detailed report of non-functional benign thyroid cystadenoma in dogs and provides relevant information about case management for this type of tumour. The presence of a large cystic structure associated with benign non-functional thyroid neoplasia may be a condition to which boxer dogs are predisposed.

Evaluation of individual low-dose dexamethasone suppression test patterns in naturally occurring hyperadrenocorticism in dogs.

BACKGROUND: Dogs with hyperadrenocorticism (HAC) may be more mildly affected at the time of diagnosis today, which could influence the prevalence of associated clinical and clinicopathological abnormalities and diagnostic test performance. Different low-dose dexamethasone suppression test (LDDST) result patterns have not been evaluated individually. OBJECTIVES: To assess the current features of HAC and evaluate if the diagnostic test performance of individual LDDST result patterns differ. ANIMALS: One hundred and twenty-three dogs undergoing investigation for HAC. METHODS: Retrospective evaluation of dogs in which a LDDST was performed and HAC confirmed or excluded by alternative means. Cases with basal cortisol concentrations (t0 ) < 1 µg/dL were excluded. Each LDDST result was classified as (a) complete suppression (t3 and t8 < 1 µg/dL), (b) lack of suppression (t3 and t8 > 1 µg/dL and both > 50% t0 ), (c) partial suppression (t3 and t8 > 1 µg/dL but either < 50% t0 ), (d) escape (t8 > 1 µg/dL and t3 < 1 µg/dL) or (e) inverse (t3 > 1 µg/dL and t8 < 1 µg/dL) pattern. RESULTS: Fifty-nine (48%) dogs were diagnosed with HAC and 64 (52%) with non-adrenal illness. Hyperadrenocorticism cases had similar clinicopathological abnormalities compared to previous reports. Sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) (95% confidence interval [CI]) of the LDDST for diagnosing HAC were 96.6 (91.9-100)%, 67.2 (55.7-78.7)%, 73.1 (63.2-82.9)%, and 95.6 (89.5-100)%, respectively. Lack of suppression pattern had the highest PPV (93.9 [85.8-100]%) followed by the partial suppression pattern (67.9 [50.6-85.2]%) and escape or inverse pattern (36.8 [15.1-58.5]%). CONCLUSIONS AND CLINICAL IMPORTANCE: A lack of suppression LDDST pattern has the highest PPV for diagnosing HAC followed by a partial suppression pattern. By contrast, the escape or inverse pattern provided limited support of HAC.

Prevalence and risk factors for hyperthyroidism in Irish cats from the greater Dublin area.

BACKGROUND: Hyperthyroidism is common in older cats. Prevalence varies geographically, but is anecdotally considered low in Ireland. The aim of this study was to document prevalence of hyperthyroidism in older cats in the greater Dublin area of Ireland and to assess environmental and clinical associations for development and identification of the disease. METHODS: Primary-care veterinary practices were requested to select cats aged 10 years or older where blood sampling was being performed for health screening or clinical investigations. Surplus serum/plasma samples were submitted to University College Dublin Diagnostic Endocrine Laboratory for total thyroxine (T4) measurement. Cats were classified as hyperthyroid, equivocal or euthyroid based on a total T4 concentration (reference interval, 15-60 nmol/L), of >60 nmol/L, 30-60 nmol/L or <30 nmol/L, respectively. Simultaneous free T4 or repeat (after 4-6 weeks) total T4 measurement was recommended in all equivocal cases. Animals receiving treatment for hyperthyroidism were excluded. A questionnaire completed by the client and veterinarian detailing historical and physical information was also required. Associations between categorical variables were analysed by Chi-square or Fisher's exact test and odds ratio (OR) calculated. A P value of <0.05 was considered statistically significant. RESULTS: Samples were submitted from 507 cats including 107 (21.1%) hyperthyroid, 54 (10.6%) equivocal and 346 (68.2%) euthyroid. The presence of goitre (P < 0.0001), tachypnoea (P = 0.0378), tachycardia (P = 0.002), polyphagia (P = 0.0003) and weight loss (P < 0.0001) were significantly associated with hyperthyroidism. Cats with goitre were more likely to be diagnosed as hyperthyroid [OR 2.85, (95% CI 1.75-4.62] compared to those without. However, goitre was only palpated in 40 of 102 (39.2%) hyperthyroid cats. Increasing age was the only significant (P < 0.002) risk factor for development of hyperthyroidism. A relationship between hyperthyroidism and sex, breed, lifestyle, parasite control, vaccination status or feeding habits was not identified. CONCLUSIONS: Hyperthyroidism is not uncommon in Irish cats. Age was the only significant risk factor for its development. The high proportion of hyperthyroid cats without palpable goitre (> 60%) may reflect failure to detect goitre and account for the perceived low prevalence of this condition in Ireland.

Platelet function and activation in Cavalier King Charles Spaniels with subclinical chronic valvular heart disease.

OBJECTIVE To assess platelet closure time (CT), mean platelet component (MPC) concentration, and platelet component distribution width (PCDW) in dogs with subclinical chronic valvular heart disease. ANIMALS 89 Cavalier King Charles Spaniels (CKCSs) and 39 control dogs (not CKCSs). PROCEDURES Platelet count, MPC concentration, PCDW, and Hct were measured by use of a hematology analyzer, and CT was measured by use of a platelet function analyzer. Murmur grade and echocardiographic variables (mitral valve regurgitant jet size relative to left atrial area, left atrial-to-aortic diameter ratio, and left ventricular internal dimensions) were recorded. Associations between explanatory variables (sex, age, murmur grade, echocardiographic variables, platelet count, and Hct) and outcomes (CT, MPC concentration, and PCDW) were examined by use of multivariate regression models. RESULTS A model with 5 variables best explained variation in CT (R(2), 0.74), with > 60% of the variance of CT explained by mitral valve regurgitant jet size. The model of best fit to explain variation in MPC concentration included only platelet count (R(2), 0.24). The model of best fit to explain variation in PCDW included platelet count and sex (R(2), 0.25). CONCLUSIONS AND CLINICAL RELEVANCE In this study, a significant effect of mitral valve regurgitant jet size on CT was consistent with platelet dysfunction. However, platelet activation, as assessed on the basis of the MPC concentration and PCDW, was not a feature of subclinical chronic valvular heart disease in CKCSs.

Urinary neutrophil gelatinase-associated lipocalin concentration changes after acute haemorrhage and colloid-mediated reperfusion in anaesthetized dogs.

OBJECTIVE: To determine changes in urine neutrophil gelatinase-associated lipocalin concentration (uNGAL) in anaesthetized Greyhound dogs that developed acute tubular damage following haemorrhage and resuscitation with colloid-based fluids. STUDY DESIGN: Prospective experimental study. ANIMALS: Seven healthy adult entire male Greyhound dogs. METHODS: During isoflurane anaesthesia, approximately 50 mL kg(-1) of blood was removed to maintain mean arterial pressure (MAP) ≤40 mmHg for 1 hour followed by gelatin-based colloid administration to maintain MAP ≥60 mmHg for 3 hours. Data, including oxygen extraction ratio and uNGAL, were collected before (T0) and immediately following (T1) haemorrhage, and hourly during reperfusion (T2-T4). After T4, dogs were euthanized and renal tissue was collected for histology. Statistical analysis was performed using repeated-measures one-way anova. Data are presented as means (95% confidence interval). RESULTS: Histology identified renal tubular epithelial damage in all dogs. Urine NGAL concentration increased from 12.1 (0-30.6) ng mL(-1) at T0 to 122.0 (64.1-180.0) ng mL(-1) by T3. Compared with T0, uNGAL was significantly higher at T3 (p = 0.016) and was increased 24-fold. CONCLUSIONS AND CLINICAL RELEVANCE: Despite wide individual variation in baseline uNGAL, increases in uNGAL were observed in all dogs, suggesting that this biomarker has the potential to detect renal tubular injury following haemorrhage-induced hypotension and colloid-mediated reperfusion.

Muscular dystrophy in the Japanese Spitz: an inversion disrupts the DMD and RPGR genes.

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.

Marked cytoreduction of a lymphocyte-rich mediastinal thymoma with neoadjuvant chemotherapy in a cat.

CASE SUMMARY: A 15-year-old neutered female domestic shorthair cat presented with lethargy and acute-onset dyspnoea. Thoracic computed tomography (CT) revealed a large, cranial mediastinal mass with an estimated volume of 180.7 cm3. Chemotherapy consisting of dexamethasone followed by L-asparaginase, prednisolone, vincristine and doxorubicin was commenced owing to the severity of disease and initial possibility of lymphoma. A diagnosis of lymphocyte-rich thymoma was made based upon histological examination, positive pancytokeratin staining, variable lymphocyte CD3 expression and T cell receptor gamma polyclonality. Thoracic CT performed 35 days after the commencement of chemotherapy showed a marked reduction in the size of the mass, with an estimated volume of 9.4 cm3. A median sternotomy and thymectomy were performed. No clinical signs have recurred 34 months after surgery. CONCLUSIONS AND RELEVANCE: The response to chemotherapy in this case was unusual, and is likely associated with the high non-neoplastic lymphoid component of the mass. The case demonstrates that preoperative chemotherapy can be used to reduce thymoma volume prior to surgery, potentially decreasing anaesthetic risk.