Compartmental fat distribution in the abdomen of dogs relative to overall body fat composition.

BACKGROUND: Adipose tissue may have different metabolic and endocrine functions depending on the region of the body in which it is located. While visceral or intra-abdominal fat has been found to contribute to leptin concentrations, insulin resistance and obesity-related diseases, there are only a few imaging studies documenting the preferential distribution of body fat to either the intra-abdominal or subcutaneous compartments in dogs. This study aimed to determine if CT-measured abdominal fat distributed preferentially to the visceral space (V) relative to the subcutaneous space (SQ), with increasing DXA-determined total body fat percentage; and if ultrasound measurements of the ventral midline subcutaneous (SAT) and visceral adipose thickness (VAT) can be used to estimate the distribution of fat to the subcutaneous and visceral abdominal spaces, in a sample of 22 dogs with variable body condition. RESULTS: Multivariate analysis showed no statistically significant correlation between visceral to subcutaneous fat ratio (V/SQ) and increasing total body fat percentage (ß = - 0.07, p = 0.733), but strong correlation with age (ß = 0.71 p = 0.002). A substantial amount of variation for the ultrasound visceral adipose thickness to subcutaneous fat thickness (VAT/SAT) could be explained by both CT V/SQ and sex (R2Adjusted = 0.477, p = 0.001), with female dogs having significant lower VAT/SAT ratios compared to the male dogs (p = 0.047). The ultrasound fat measurements appeared moderately reliable, but a larger sample number is required to confirm this. CONCLUSIONS: The findings suggest that dogs with a relatively healthy to slightly overweight body condition score, distribute fat relatively similarly between their peritoneal (visceral) and subcutaneous abdominal compartments with increasing total body fat percentage. However, there was increased fat distribution to the peritoneal space relative to the subcutaneous space with increasing age. Further, abdominal ultrasound may be useful in estimating the ratio of fat distribution to both the abdominal visceral and subcutaneous spaces.

Abdominal volume computed tomography assessment of body composition in dogs.

BACKGROUND: Computed tomography (CT) has been used to estimate body composition and determine tissue distribution in dogs, despite limited validation. This may introduce error into estimates of body composition studies and its effect on health in dogs. Further, the modality has not been validated against dual-energy X-ray absorptiometry (DXA) or over a wide range of dog breeds, ages and sexes. The objective of this study was to validate the use of semi-automated, abdominal volume CT for estimating total body composition of dogs relative to DXA. Twenty-two staff-owned dogs (weighing between 5.1-60 kg) were sedated and underwent full body DXA scan and abdominal CT. Abdominal tissue composition was estimated by CT using semi-automated volume segmentation, over predetermined tissue Hounsfield threshold values. Abdominal tissue composition determined by the various CT threshold ranges was compared to total body composition determined by DXA. RESULTS: Abdominal tissue composition estimated by CT strongly correlated with the estimates derived from DXA with a small Bland-Altman mean percentage differences in values: total body mass (- 250/2000HU: r2 = 0.985; - 1.10%); total fat mass (- 250/-25HU: r2 = 0.981; - 1.90%); total lean tissue mass (- 25/150HU: r2 = 0.972; 3.47%); and total bone mineral content (150/2000HU: r2 = 0.900; - 0.87%). Although averaged CT values compared well to DXA analysis, there was moderate variation in the individual predicted values. There was near perfect inter- and intra-observer agreement in segmentation volumes for abdominal fat. CONCLUSIONS: Abdominal volume computed tomography (CT) accurately and reliably estimates total body composition in dogs, but greater variations may be observed in dogs weighing less than 10 kg.

Concentrations of interleukin-6, -8, -10 and tumour necrosis factor-α in the faeces of dogs with acute diarrhoea.

AIM: To compare the concentration of faecal cytokines interleukin (IL)-6, -8, -10, and tumour necrosis factor (TNF)-α in dogs with acute diarrhoea with clinically normal (non-diarrhoeic) dogs. METHODS: A total of 14 dogs presenting with acute diarrhoea, and 25 dogs with no history of gastrointestinal signs in the 2 months prior to enrolment, were recruited from two veterinary hospitals in Melbourne, Australia. Concentrations of IL-6, -8, -10, and TNF-α were measured in faecal samples using canine-specific ELISA. RESULTS: The diarrhoeic dogs were diagnosed with or managed for acute gastroenteritis (n = 6), extra-intestinal neoplasia (n = 2), parvoviral enteritis (n = 1), hepatopathy (n = 1), acute pancreatitis (n = 1), hypoadrenocorticism (n = 1), gastric dilatation volvulus (n = 1) and myelopathy (n = 1). IL-6 was detectable in the faeces of 10/14 (71%) diarrhoeic and 7/25 (28%) non-diarrhoeic dogs, and median concentrations were 10.8 (min 0.0, max 54.0) and 2.0 (min 0.0, max15.0) pg/mL, respectively (p = 0.01). IL-8 was detectable in the faeces of all diarrhoeic and 11 non-diarrhoeic dogs, and median concentrations were 149.7 (min 3.72, max 730.1) and 3.4 (min 0.0, max 22.5) pg/mL, respectively (p < 0.001). TNF-α was detected in the faeces of two of the diarrhoeic dogs (3.4 and 15.6 pg/mL) and none of the non-diarrhoeic dogs. IL-10 was not detected in the faeces of any dog. CONCLUSIONS: Faecal concentrations of IL-6 and -8 were higher in diarrhoeic compared to non-diarrhoeic dogs, and are therefore potential candidates for non-invasive biomarkers to assess the severity and resolution of acute intestinal disease in dogs. However their correlation with disease progression and severity needs to be further investigated before their full clinical application can be determined.

The exogenous fluorophore, fluorescein, enables in vivo assessment of the gastrointestinal mucosa via confocal endomicroscopy: optimization of intravenous dosing in the dog model.

This study described the pharmacokinetics of the intravenous fluorophore, fluorescein, and aimed to evaluate its utility for use in upper gastrointestinal confocal endomicroscopy (CEM). Six healthy, mature, mixed-breed dogs were anesthetized and then dosed intravenously with fluorescein at 15 mg/kg. Blood samples were collected at predetermined time-points. Dogs were examined by upper gastrointestinal confocal endomicroscopy and monitored for adverse effects. Plasma fluorescein concentrations were measured using high-performance liquid chromatography (HPLC) with UV/Vis detection. Mean plasma concentration at 5 min was 57.6 ± 18.2 mg/L, and plasma concentrations decreased bi-exponentially thereafter with a mean concentration of 2.5 mg/L ± 1.26 at 120 min. Mean terminal plasma elimination half-life (t½ß ) was 34.8 ± 8.94 min, and clearance was 9.1 ± 3.0 mL/kg/min. Apparent volume of distribution at steady-state was 0.3 ± 0.06 L/kg. Fluorescein provided optimal fluorescent contrast to enable in vivo histologically equivalent evaluation of topologic mucosal morphology within the first 30 min following intravenous administration. Adverse effects were not observed. Based upon the calculated clearance, a constant rate infusion at a rate of 0.18 mg/kg/min is predicted to be adequate, following an initial loading dose (2 mg/kg), to maintain plasma concentration at 20 mg/L for optimal CEM imaging during the study period.

Bodyweight and body condition scores of Australian British shorthaired cats, 2008-2017.

Obesity is the most common nutritional problem in companion animals today, and Australian British shorthair (BSH) cats have been shown to have a greater likelihood of being overweight relative to other cat breeds. The objectives of this research were to quantify bodyweight (BW) and body condition scores (BCSs) of BSH cats attending first opinion practice in Australia for the period 2008-2017 and to determine if: (1) being classified as overweight was associated with geographical location (urban versus rural and socio-economic index); and (2) BW recorded in the first 12 months of life was associated with length of life beyond 12 months. Electronic medical records from BSH cats were obtained from VetCompass Australia and used for BW and BCS analysis. Desexed males (n = 971) had the highest mean BW followed by entire males (n = 79), desexed females (n = 815), and entire females (n = 82). The desexed males, desexed females, and entire females had a mean BCS classified as overweight using a 1-to-9 point BCS scale. The entire male population was the only group with a mean BCS classified as ideal. No statistically significant association between BW and urban-rural status and no consistent trend between BW and socioeconomic deprivation was found. For cats with at least one BW measurement in the first 12 months of life that was ≤3.3 kg, the age when 20 percent of the group had died or were euthanised was 12.3 (95% CI 11.7 to 13.1) years. For cats with at least one BW measurement in the first 12 months of life that was ≥3.3 kg age, the age when 20 percent of the group had died or were euthanised was 6.6 (95% CI 5.2 to 6.6) years. This was a substantial clinical difference in survival. The study concluded that a large proportion of BSH cats attending first opinion veterinary clinics in Australia between 2008 and 2017 (48%) were classified as overweight. Cats less than 12 months of age that were greater than 3.3 kg had a shortened lifespan beyond 12 months of age compared with cats that were less than 3.3 kg.

Remission of histiocytic ulcerative colitis in Boxer dogs correlates with eradication of invasive intramucosal Escherichia coli.

BACKGROUND: Historically, histiocytic ulcerative (HUC) (or granulomatous) colitis of Boxer dogs was considered an idiopathic immune-mediated disease with a poor prognosis. Recent reports of dramatic responses to enrofloxacin and the discovery of invasive Escherichia coli within the colonic mucosa of affected Boxer dogs support an infectious etiology. HYPOTHESIS: Invasive E. coli is associated with colonic inflammation in Boxer dogs with HUC, and eradication of intramucosal E. coli correlates with clinical and histologic remission. ANIMALS: Seven Boxer dogs with HUC. METHODS: Prospective case series. Colonic biopsies were obtained at initial evaluation in 7 dogs, and in 5 dogs after treatment with enrofloxacin. Biopsies were evaluated by standardized histopathology, and fluorescence in situ hybridization (FISH) with probes to eubacteria and E. coli. RESULTS: Intramucosal E. coli was present in colonic biopsies of 7/7 Boxers with HUC. Clinical response was noted in all dogs within 2 weeks of enrofloxacin (7 + or - 3.06 mg/kg q24 h, for 9.5 + or - 3.98 weeks) and was sustained in 6 dogs (median disease-free interval to date of 47 months, range 17-62). FISH was negative for E. coli in 4/5 dogs after enrofloxacin. E. coli resistant to enrofloxacin were present in the FISH-positive dog that relapsed. CONCLUSIONS AND CLINICAL RELEVANCE: The correlation between clinical remission and the eradication of mucosally invasive E. coli during treatment with enrofloxacin supports the causal involvement of E. coli in the development of HUC in susceptible Boxer dogs. A poor response to enrofloxacin treatment might be due to colonization with enrofloxacin-resistant E. coli.

Treatment response and long term follow up in nineteen dogs diagnosed with chronic enteropathy in Australia.

Chronic enteropathy (CE) in dogs is common worldwide, but little data is available from Australia. The aim of this study was to describe treatment response and long-term outcome in a cohort of dogs with CE. Dogs were prospectively enrolled at Murdoch University and the University of Melbourne. After diagnostic investigation to rule out diseases other than CE, dogs underwent sequential therapeutic trials until achieving a clinical response (diet then antibiotics, and finally immunosuppressants). Success was defined as 75% reduction of clinical severity for a minimum of five weeks. A total of 21 dogs were enrolled, and 19 completed the study. One dog was euthanised for lack of response to treatment and one excluded for lack of owner compliance. Most dogs responded to diet (n = 10), followed by antibiotics (n = 7) and immunosuppressants (n = 2). Long-term remission (median 21.1 months, [3.0-44.7]) was achieved in eight out of ten dietary responders without additional treatment. In contrast, only two dogs with antibiotic response remained in long-term remission, of which one needed on-going antibiotic treatment. Longer term remission was achieved in the two dogs treated with immunosuppressants with on-going low dose therapy. This study concludes that most dogs referred for CE in Australia respond to dietary treatment (even after previous dietary interventions), and remission is long-term compared to dogs treated with an antibiotic. Furthermore, the need for long-term antibiotics in some dogs to maintain response may lead to antibiotic resistance. This study supports adequate dietary trials for CE in dogs, and a need for alternative second-line treatments.

Ascites due to pre-sinusoidal portal hypertension in dogs: a retrospective analysis of 17 cases.

Accumulation of a pure transudate abdominal effusion in the absence of significant hypoalbuminaemia is uncommon in dogs and is due to pre-sinusoidal portal hypertension. Reported causes of pre-sinusoidal portal hypertension vary, but suggest a reasonable prognosis. A retrospective analysis of 17 dogs that presented to our institution with ascites due to pre-sinusoidal portal hypertension identified idiopathic hepatic fibrosis or canine chronic hepatitis as the underlying cause in the majority of cases. Twelve (70.5%) dogs were 4 years of age or younger at time of presentation. Total serum protein was higher in dogs with chronic hepatitis than it was in dogs without inflammatory disease. The prognosis was generally poor and no histological, imaging or biochemical parameters were useful as prognostic indicators. Dogs died or were euthanased due to severe clinical signs associated with the portal hypertension and/or perceived poor prognosis.

Prevalence and risk factors for medical events following exercise at Australian Greyhound race meetings.

AIM: A prospective, observational study to determine the prevalence of post-exercise conditions at Australian Greyhound race meetings and to assess association with race performance and other environmental, race- and dog-related factors was undertaken. METHODS: A total of 4020 starters were observed (2813 Greyhounds, 1009 trainers, 536 races, 52 race meets, 48 race dates and 11 race tracks) following a race. The presence of diaphragmatic flutter (DF), ataxia, seizure, collapse or sudden death was recorded. Risk factors were screened by univariable logistic regression prior to multivariable backward stepwise model building. RESULTS: In this study, 962 starters (n = 768 dogs) had DF (23.9%), 16 starters were ataxic (0.4%) and there were no observed cases of collapse, seizure or sudden death. Race track location, increasing race distance, race grade based on increasing 1st place prize value, lower (earlier) race number at the meeting, age, a previous observation of DF at the last start, females, colour (white) and better finishing position were all associated with an increased risk of a Greyhound being observed with DF. However, when logistic regression assessing the random effect of dog was performed, the presence of previous DF was not significant. In this cohort, DF was common following strenuous exercise in Greyhounds and on its own does not appear to result in reduced performance or distress to the animal. CONCLUSION: The incidence of ataxia was low and collapse, seizure and sudden death were not observed. However, even though uncommon, ataxia has welfare concerns for racing Greyhounds that warrants further investigation.

Gastrokine mRNA expression in gastric tissue from dogs with helicobacter colonisation but without inflammatory change during treatment.

Gastrokines (GKNs) are bioactive substances secreted by gastric cells. Evidence supports functional roles for GKNs in gastric homeostasis, immune responses and tumour suppression. Down-regulation has been reported in Helicobacter pylori associated gastritis and other inflammatory gastrointestinal conditions in mice and people. The aim of this study was to evaluate GKN gene expression in dogs positive for other Helicobacter spp. both before and after treatment. Expression of Gkn-1 and Gkn-2 mRNA was studied in endoscopic biopsy samples collected from seven healthy dogs over three time-points pre- (T0) and at 1 and 18 weeks post-treatment for Helicobacter spp. colonisation (T1 & T2). The relative expression software tool (REST) was used to provide efficiency corrected expression ratios for comparisons between groups and these results were compared to a standard 2ΔΔCT methodology. Compared with T1 Gkn1 and Gkn2 mRNA expression was greater at T0 by a mean factor of 2.53 (SE=1.83-3.54) for Gkn1 (P=0.000) and 2.85 (SE=2.23-3.75) for Gkn2 (P=0.000). This difference was attenuated when comparisons were made between T0 and T2. Histopathological evidence of gastritis was not present in any Helicobacter spp. positive sample. When compared to post-eradication samples Gkn gene expression is increased in the presence of Helicobacter spp. in dogs without evidence for concurrent inflammation. Further evaluation is required to determine the relevance of this finding, however given a suspected role in gastric homeostasis, up-regulation of GKN1 and GKN2 could limit development of gastritis in Helicobacter spp. positive dogs.

Cricopharyngeal dysphagia and phenobarbitone-responsive sialoadenosis in a Miniature Poodle.

CASE REPORT: An 11-year-old male neutered Miniature Poodle was investigated for ptyalism, weight loss and anorexia. Cricopharyngeal dysphagia was diagnosed using fluoroscopy, and non-inflammatory salivary disease was diagnosed using a combination of cytology and computed tomography. The dog was successfully managed with phenobarbitone. CONCLUSION: To the authors' knowledge this is the first time acquired cricopharyngeal dysphagia and phenobarbitone-responsive sialoadenosis have been described together.

Scintigraphic Assessment of Deposition of Radiolabeled Fluticasone Delivered from a Nebulizer and Metered Dose Inhaler in 10 Healthy Dogs.

BACKGROUND: Aerosolized medications are increasingly being used to treat respiratory diseases in dogs. No previous studies assessing respiratory tract deposition of radiolabeled aerosols have been performed in conscious dogs. HYPOTHESIS/OBJECTIVES: Assess respiratory tract deposition of radiolabeled, inhalant corticosteroid (fluticasone propionate labeled with 99m Tc) delivered from a nebulizer and metered dose inhaler (MDI) to healthy dogs. ANIMALS: Ten healthy Foxhounds. METHODS: Prospective, randomized, cross-over pilot study. Initial inhalation method (nebulizer or MDI) was randomly assigned. Treatments were crossed over after a 7-day washout period. Treatments initially were performed using sedation. Dogs were imaged using 2-dimensional planar scintigraphy, with respiratory tract deposition quantified by manual region-of-interest analysis. Deposition calculated as percentage of delivered dose. Six of 10 dogs were randomly selected and reassessed without sedation. RESULTS: Inhalation method had significant effect on respiratory tract deposition (P = 0.027). Higher deposition was achieved by nebulization with mean deposition of 4.2% (standard deviation [SD], 1.4%; range, 1.9-6.1%); whereas MDI treatment achieved a mean of 2.3% (SD, 1.4%; range, 0.2-4.2%). Nebulization achieved higher respiratory tract deposition than MDI in 7 of 10 dogs. No statistical difference (P = 0.68) was found between mean respiratory tract deposition achieved in dogs when unsedated (3.8%; SD, 1.5%) or sedated (3.6%; SD, 1.7%). CONCLUSIONS AND CLINICAL IMPORTANCE: Study confirms respiratory tract deposition of inhalant medications delivered from a nebulizer and MDI in healthy dogs, breathing tidally with and without sedation. Respiratory tract deposition in these dogs was low compared to reported deposition in adult humans, but similar to reported deposition in children.

Lymphocytic-plasmacytic thyroiditis and glomerulonephritis in a boxer.

An 18-month-old boxer was presented for investigation of profound lethargy, and primary hypothyroidism was diagnosed. A strong antithyroglobulin antibody titre was also present, indicating lymphocytic (immune-mediated) thyroiditis as the cause of hypothyroidism. A concurrent protein-losing glomerulonephropathy was also detected, although the aetiology could not be determined at initial presentation. Thyroid replacement and dietary therapy were prescribed. The dog improved clinically for approximately 12 months when it was re-presented with poorly controlled hypothyroidism and renal failure. Postmortem examination confirmed the presence of lymphocytic-plasmacytic thyroiditis, in conjunction with membranoproliferative glomerulonephritis and renal failure.

Pyruvate kinase deficiency in a Somali cat in Australia.

A 7-year-old neutered male Somali cat, bred in Western Australia, was presented for investigation of jaundice and severe anaemia. Splenomegaly and hepatomegaly were evident on physical examination. Severe anaemia, along with leukopenia and increased liver enzymes, were present on laboratory evaluation. Clinical investigation identified cholangitis and treatment for this resolved the jaundice but failed to resolve the anaemia. Treatment for Mycoplamsa haemofelis was administered concurrently. Genetic testing was then performed and pyruvate kinase deficiency was identified, the first time this has been reported in an Australian cat. Treatment with immunosuppressive medication was not successful.

Treatment of insulinoma in a springer spaniel with streptozotocin.

An eight-year-old, female springer spaniel was treated for metastatic insulinoma with a single intravenous dose of 500 mg/m2 streptozotocin (SZN), and pre- and post-treatment diuresis. A tapering dose of corticosteroids was also administered over a 28 day period. SZN and corticosteroid administration resulted in resolution of hypoglycaemia and subsequent development of diabetes mellitus. Further metastases caused cervical spinal pain and the dog was euthanased 118 days after SZN administration. SZN can be safely used for the treatment of canine insulinoma, but, when compared with other published cases, a marked variation in clinical response to this drug exists and further study is warranted.

Review of feline pancreatitis part one: the normal feline pancreas, the pathophysiology, classification, prevalence and aetiologies of pancreatitis.

The cellular mechanisms involved once pancreatitis has been initiated are reasonably well understood. The events leading up to this process are less well established. Much of our current understanding of pancreatitis in cats has been determined from experiments in cats or extrapolated from other species. The normal anatomy and function of the pancreas and a review of the current state of knowledge about the pathophysiology of pancreatitis is discussed. The current prevalence of feline pancreatitis is unknown, but the disease is being reported with increasing frequency. The aetiology of pancreatitis and the types of pancreatic inflammation present in cats is different from other species, such as the dog, a species where the disease is considered more common. Concurrent diseases are often present that may be more serious than the pancreatic inflammation and the treatment of these diseases is often complicated by pancreatitis.

Review of feline pancreatitis part two: clinical signs, diagnosis and treatment.

In the past decade pancreatitis has become recognised as a significant disease in the cat. Chronic, mild pancreatitis is often associated with more commonly diagnosed diseases such as inflammatory bowel disease or cholangitis/cholangiohepatitis. Furthermore, acute pancreatitis with similar complications to those seen in dogs is now diagnosed more frequently in cats. Unfortunately, the clinical signs and clinicopathological findings in cats with pancreatitis are often non-specific and vague. The lack of specific signs often results in a diagnosis being made only when the veterinary surgeon has a strong index of suspicion for pancreatitis and vigorously pursues that diagnosis. Pancreatitis is an important disease in cats, has been implicated as a potential cause of diabetes mellitus, and when present complicates the treatment of diabetes and other intra-abdominal diseases in cats.

Intra-atrial rhabdomyoma causing chylopericardium and right-sided congestive heart failure in a dog.

A six-year-old Staffordshire bull terrier had a four-week history of progressive lethargy, ascites and exercise intolerance. A mass 3 cm in diameter obliterating the right atrial lumen was detected by echocardiographic examination. There were lactescent pericardial and serosanguineous pleural effusions. Histological and immunochemical examinations showed that the mass was a primary rhabdomyoma.

Plasma and urinary trypsinogen activation peptide in healthy dogs, dogs with pancreatitis and dogs with other systemic diseases.

OBJECTIVE: To determine the specificity and sensitivity of plasma and urinary trypsinogen activation peptide (TAP) concentrations in diagnosing pancreatitis in dogs. DESIGN: Retrospective analysis of clinical cases. PROCEDURE: Dogs were classified into three groups: healthy animals, dogs with confirmed pancreatitis and dogs with nonpancreatic disease, which clinically or biochemically resembled pancreatitis. This last group was further subdivided into dogs with renal and those with nonrenal disease. The plasma and urinary TAP concentration was determined by a competitive enzyme immunoassay. Clinical cases additionally had serum trypsin-like immunoreactivity concentration measured, as well as radiography and ultrasound of the abdomen and further diagnostic procedures. Nonparametric analysis of variance (Kruskal-Wallis test) was performed using Statistix 4.0 program. RESULTS: There was a wide range of urinary TAP concentration in healthy dogs (mean 52.30 nmol/L, standard deviation 55.25) that made interpretation of urinary TAP concentrations difficult in the other groups. There was a narrow reference range for plasma TAP (mean 2.67 nmol/L, standard deviation 0.93). Plasma and urinary TAP concentrations, as well as urinary TAP to creatinine ratio, were all increased in dogs that died with necrotising pancreatitis. Values were not increased in mild, interstitial pancreatitis. Increased plasma TAP concentrations were also present in dogs with severe renal disease. CONCLUSION: Plasma TAP concentration is a good prognostic indicator in naturally occurring pancreatitis in dogs. The failure of TAP to increase in mild pancreatitis, and the increase present in severe renal disease, suggests its measurement has limited application as a sole diagnostic tool for canine pancreatitis. Further investigations are required in order to explain the large variability of urinary TAP concentration and the presence of circulating TAP in healthy dogs.

In vivo histologically equivalent evaluation of gastric mucosal topologic morphology in dogs by using confocal endomicroscopy.

BACKGROUND: Confocal endomicroscopy (CEM) is an endoscopic technology permitting in vivo cellular and subcellular imaging. CEM aids real-time clinical assessment and diagnosis of various gastrointestinal diseases in people. CEM allows in vivo characterization of small intestinal mucosal morphology in dogs. OBJECTIVE: To determine the feasibility of CEM to evaluate gastric mucosal morphology in dogs and to characterize the appearance in healthy dogs. ANIMALS: Fourteen clinically healthy research colony dogs. METHODS: Experimental study. Under general anesthesia, dogs underwent standard endoscopic evaluation and CEM of the gastric mucosa. In the initial 6 dogs, fluorescent contrast was provided with the fluorophore acriflavine (0.05% solution), applied topically. Subsequently, 8 dogs were assessed using a combination of fluorescein (10% solution, 15 mg/kg IV), followed by acriflavine administered topically. For each fluorophore, a minimum of 5 sites were assessed. RESULTS: Confocal endomicroscopy provided high quality in vivo histologically equivalent images of the gastric mucosa, but reduced flexibility of the endoscope tip limited imaging of the cranial stomach in some dogs. Intravenous administration of fluorescein allowed assessment of cellular cytoplasmic and microvasculature features. Topical application of acriflavine preferentially stained cellular nucleic acids, allowing additional evaluation of nuclear morphology. Identification of Helicobacter-like organisms was possible in 13 dogs. CONCLUSION AND CLINICAL IMPORTANCE: Confocal endomicroscopy provides in vivo images allowing assessment of gastric mucosal morphology during endoscopy, potentially permitting real-time diagnosis of gastrointestinal disease.