Healthy Research Dogs Research Articles

Characterization and modulation of the pro-inflammatory effects of immune cells in the canine intervertebral disk.

Intervertebral disk (IVD) degeneration affects both humans and canines and is a major cause of low back pain (LBP). Mast cell (MC) and macrophage (MØ) infiltration has been identified in the pathogenesis of IVD degeneration (IVDD) in the human and rodent model but remains understudied in the canine. MC degranulation in the IVD leads to a pro-inflammatory cascade and activates protease activated receptor 2 (PAR2) on IVD cells. The objectives of the present study are to: (1) highlight the pathophysiological changes observed in the degenerate canine IVD, (2) further characterize the inflammatory effect of MCs co-cultured with canine nucleus pulposus (NP) cells, (3) evaluate the effect of construct stiffness on NP and MCs, and (4) identify potential therapeutics to mitigate pathologic changes in the IVD microenvironment. Canine IVD tissue was isolated from healthy autopsy research dogs (beagle) and pet dogs undergoing laminectomy for IVD herniation. Morphology, protein content, and inflammatory markers were assessed. NP cells isolated from healthy autopsy (Mongrel hounds) tissue were co-cultured with canine MCs within agarose constructs and treated with cromolyn sodium (CS) and PAR2 antagonist (PAR2A). Gene expression, sulfated glycosaminoglycan content, and stiffness of constructs were assessed. CD 31+ blood vessels, mast cell tryptase, and macrophage CD 163+ were increased in the degenerate surgical canine tissue compared to healthy autopsy. Pro-inflammatory genes were upregulated when canine NP cells were co-cultured with MCs and the stiffer microenvironment enhanced these effects. Treatment with CS and PAR2 inhibitors mediated key pro-inflammatory markers in canine NP cells. There is increased MC, MØs, and vascular ingrowth in the degenerate canine IVD tissue, similar to observations in the clinical population with IVDD and LBP. MCs co-cultured with canine NP cells drive inflammation, and CS and PAR2A are potential therapeutics that may mitigate the pathophysiology of IVDD in vitro.

Novel subcutaneous cytarabine infusion with the Omnipod system in dogs with meningoencephalomyelitis of unknown etiology.

To investigate the feasibility and pharmacokinetics of cytarabine delivery as a subcutaneous continuous-rate infusion with the Omnipod system. 6 client-owned dogs diagnosed with meningoencephalomyelitis of unknown etiology were enrolled through the North Carolina State University Veterinary Hospital. Cytarabine was delivered at a rate of 50 mg/m2/hour as an SC continuous-rate infusion over 8 hours using the Omnipod system. Plasma samples were collected at 0, 4, 6, 8, 10, 12, and 14 hours after initiation of the infusion. Plasma cytarabine concentrations were measured by high-pressure liquid chromatography. A nonlinear mixed-effects approach generated population pharmacokinetic parameter estimates. The mean peak plasma concentration (Cmax) was 7,510 ng/mL (range, 5,040 to 9,690 ng/mL; SD, 1,912.41 ng/mL), average time to Cmax was 7 hours (range, 4 to 8 hours; SD, 1.67 hours), terminal half-life was 1.13 hours (SD, 0.29 hour), and the mean area under the curve was 52,996.82 hours X μg/mL (range, 35,963.67 to 71,848.37 hours X μg/mL; SD, 12,960.90 hours X μg/mL). Cmax concentrations for all dogs were more than 1,000 ng/mL (1.0 μg/mL) at the 4-, 6-, 8-, and 10-hour time points. An SC continuous-rate infusion of cytarabine via the Omnipod system is feasible in dogs and was able to achieve a steady-state concentration of more than 1 μg/mL 4 to 10 hours postinitiation of cytarabine and a Cmax of 7,510 ng/mL (range, 5,040 to 9,690 ng/mL; SD, 1,912.41 ng/mL). These are comparable to values reported previously with IV continuous-rate infusion administration in healthy research Beagles and dogs with meningoencephalomyelitis of unknown etiology.

Population Pharmacokinetics of Intravenous Amoxicillin Combined With Clavulanic Acid in Healthy and Critically Ill Dogs.

Background: Data regarding antimicrobial pharmacokinetics (PK) in critically ill dogs are lacking and likely differ from those of healthy dogs. The aim of this work is to describe a population PK model for intravenous (IV) amoxicillin–clavulanic acid (AMC) in both healthy and sick dogs and to simulate a range of clinical dosing scenarios to compute PK/PD cutoffs for both populations.Methods: This study used a prospective clinical trial in normal and critically ill dogs. Twelve client-owned dogs hospitalized in the intensive care unit (ICU) received IV AMC 20 mg/kg every 8 h (0.5-h infusion) during at least 48 h. Eight blood samples were collected at predetermined times, including four trough samples before the next administration. Clinical covariates and outcome were recorded, including survival to discharge and bacteriologic clinical failure. Satellite PK data were obtained de novo from a group of 12 healthy research dogs that were dosed with a single AMC 20 mg/kg IV. Non-linear mixed-effects model was used to estimate the PK parameters (and the effect of health upon them) together with variability within and between subjects. Monte Carlo simulations were performed with seven dosage regimens (standard and increased doses). The correlation between model-derived drug exposure and clinical covariates was tested with Spearman's non-parametric correlation analysis. Outcome was recorded including survival to discharge and bacteriologic clinical failure.Results: A total of 218 amoxicillin concentrations in plasma were available for healthy and sick dogs. A tricompartmental model best described the data. Amoxicillin clearance was reduced by 56% in sick dogs (0.147 L/kg/h) compared with healthy dogs (0.336 L/kg/h); intercompartmental clearance was also decreased (p <0.01). None of the clinical data covariates were significantly correlated with individual exposure. Monte Carlo simulations showed that higher PK/PD cutoff values of 8 mg/L could be reached in sick dogs by extending the infusion to 3 h or doubling the dose.Conclusions: The PK of AMC is profoundly different in critically ill dogs compared with normal dogs, with much higher interindividual variability and a lower systemic clearance. Our study allows to generate hypotheses with regard to higher AMC exposure in clinical dogs and provides supporting data to revise current AMC clinical breakpoint for IV administration.

Sedation with dexmedetomidine is associated with transient gallbladder wall thickening and peritoneal effusion in some dogs undergoing abdominal ultrasonography.

BackgroundDexmedetomidine often is used for sedation before or during abdominal ultrasonography. The effect of dexmedetomidine on gallbladder wall thickness is unknown.Hypothesis/ObjectivesTo investigate the relationship between dexmedetomidine administration and gallbladder wall thickening in dogs. The hypothesis was that sedation with dexmedetomidine will cause transient gallbladder wall thickening. Gallbladder wall thickness will be associated with duration of sedation and recumbency position.AnimalsSeventy‐nine client owned dogs and 10 healthy research dogs.MethodsA prospective observational study (n = 79) was used to establish the prevalence of gallbladder wall thickening (> 2.0 mm) after sedation with dexmedetomidine. A randomized, crossover study (n = 10) was used to evaluate the effect of time and recumbency position on the development of gallbladder wall thickening. Linear mixed models were used.ResultsThe proportion of client‐owned dogs that developed gallbladder wall thickening was 24.05% (19/79; 95% confidence interval [CI], 15.1%‐35.0%) with a median dose of dexmedetomidine of 5.0 μg/kg (range, 2.0‐12.5 μg/kg). After sedation, the proportion of research dogs that developed gallbladder wall thickening in left lateral (5/10, 50%; 95% CI, 18.7%‐81.3%) and dorsal (7/10, 70%; 95% CI, 34.8%‐93.3%) recumbency did not differ significantly (P = .45). Gallbladder wall thickening developed within 20 to 40 minutes. Duration of sedation was significantly associated with thickening of the gallbladder wall (P < .001). Five dogs developed 9 instances of peritoneal effusion in both lateral (5) and dorsal (4) recumbency.Conclusions and Clinical ImportanceSedation with dexmedetomidine is associated with gallbladder wall thickening (> 2.0 mm) and peritoneal effusion that could be confused with pathologic etiologies.

Effects of Synbiotics on the Fecal Microbiome and Metabolomic Profiles of Healthy Research Dogs Administered Antibiotics: A Randomized, Controlled Trial.

Background: Antibiotic-associated gastrointestinal signs occurred in 100% of dogs administered enrofloxacin with metronidazole in a previous study, and signs partially were mitigated by synbiotics. The objective of this randomized, double-blinded, placebo-controlled trial was to compare the fecal microbiome and metabolome of dogs administered enrofloxacin and metronidazole, followed by either a placebo or a bacterial/yeast synbiotic combination.Methods: Twenty-two healthy research dogs were randomized to two treatment groups. There were three study periods: baseline, treatment, and washout. Dogs were administered enrofloxacin (10 mg/kg qd) and metronidazole (12.5 mg/kg BID), followed 1 h later by placebo or a commercially-available synbiotic combination (BID), per os for 21 days with reevaluation 56 days thereafter. Fecal samples were collected on days 5–7 (baseline), 26–28, and 82–84. The fecal microbiome was analyzed by qPCR and sequencing of 16S rRNA genes; time-of-flight mass spectrometry was used to determine metabolomic profiles. Split plot repeated measures mixed model ANOVA was used to compare results between treatment groups. P < 0.05 was considered significant, with Benjamini and Hochberg's False Discovery Rate used to adjust for multiple comparisons.Results: Alpha diversity metrics differed significantly over time in both treatment groups, with incomplete recovery by days 82–84. Beta diversity and the dysbiosis index differed significantly over time and between treatment groups, with incomplete recovery at days 82–84 for dogs in the placebo group. Significant group-by-time interactions were noted for 15 genera, including Adlercreutzia, Bifidobacterium, Slackia, Turicibacter, Clostridium (including C. hiranonis) [Ruminococcus], Erysipelotrichaceae_g_, [Eubacterium], and Succinivibrionaceae_g_. Concurrent group and time effects were present for six genera, including Collinsella, Ruminococcaceae_g_, and Prevotella. Metabolite profiles differed significantly by group-by-time, group, and time for 28, 20, and 192 metabolites, respectively. These included short-chain fatty acid, bile acid, tryptophan, sphingolipid, benzoic acid, and cinnaminic acid metabolites, as well as fucose and ethanolamine. Changes in many taxa and metabolites persisted through days 82–84.Conclusion: Antibiotic administration causes sustained dysbiosis and dysmetabolism in dogs. Significant group-by-time interactions were noted for a number of taxa and metabolites, potentially contributing to decreased antibiotic-induced gastrointestinal effects in dogs administered synbiotics.

Use of intravenous lidocaine to treat dexmedetomidine-induced bradycardia in sedated and anesthetized dogs

ObjectiveTo assess cardiopulmonary function in sedated and anesthetized dogs administered intravenous (IV) dexmedetomidine and subsequently administered IV lidocaine to treat dexmedetomidine-induced bradycardia. Study designProspective, randomized, crossover experimental trial. AnimalsA total of six purpose-bred female Beagle dogs, weighing 9.1 ± 0.6 kg (mean ± standard deviation). MethodsDogs were randomly assigned to one of three treatments: dexmedetomidine (10 μg kg–1 IV) administered to conscious (treatments SED1 and SED2) or isoflurane-anesthetized dogs (end-tidal isoflurane concentration 1.19 ± 0.04%; treatment ISO). After 30 minutes, a lidocaine bolus (2 mg kg–1) IV was administered in treatments SED1 and ISO, followed 20 minutes later by a second bolus (2 mg kg–1) and a 30 minute lidocaine constant rate infusion (L-CRI) at 50 (SED1) or 100 μg kg–1 minute–1 (ISO). In SED2, lidocaine bolus and L-CRI (50 μg kg–1 minute–1) were administered 5 minutes after dexmedetomidine. Cardiopulmonary measurements were obtained after dexmedetomidine, after lidocaine bolus, during L-CRI and 30 minutes after discontinuing L-CRI. A mixed linear model was used for comparisons within treatments (p < 0.05). ResultsWhen administered after a bolus of dexmedetomidine, lidocaine bolus and L-CRI significantly increased heart rate and cardiac index, decreased mean blood pressure, systemic vascular resistance index and oxygen extraction ratio, and did not affect stroke volume index in all treatments. Conclusion and clinical relevanceLidocaine was an effective treatment for dexmedetomidine-induced bradycardia in healthy research dogs.

Neutrophil extracellular traps in stored canine red blood cell units.

BackgroundNeutrophil extracellular traps (NETs), webs of DNA and citrullinated histones extruded from activated neutrophils cause transfusion‐related acute lung injury. Supernatants of stored red blood cell (RBC) units might promote NETosis in neutrophils from the units or from transfusion recipients.Hypotheses(1) NETs form during storage of canine RBC, (2) leukoreduction (LR) before storage of RBC reduces NETosis, and (3) supernatant from stored, nonleukoreduced (NLR) RBC units induces NETosis in healthy canine neutrophils modeling transfusion recipients.AnimalsSix healthy purpose‐bred research dogs were utilized for blood donation.MethodsProspective controlled study. RBC units were collected from each dog, aseptically divided into 2 equal subunits, 1 of which was leukoreduced, and stored for 42 days. Stored units were sampled biweekly for quantification of NET markers citrullinated histone H3 (Western blot) and cell‐free DNA (cfDNA) (DNA dye binding). Unit supernatants were applied ex vivo to canine neutrophils and extracellular DNA release representing NETosis was assessed.ResultsMarkers of NETs increased during RBC storage (cfDNA P < .0001 and citrullinated H3 P = .0002) and were higher in NLR than LR units (day 42 LR cfDNA 0.34 ± 0.82 ng/mL vs day 42 NLR 1361.07 ± 741.00 ng/mL, P < .0001; day 42 LR citrullinated H3 0.19 ± 0.13 AU vs NLR 0.57 ± 0.34 AU, P = .007). Isolated neutrophils did not form NETs when exposed to stored canine RBC supernatant.Conclusions and Clinical ImportanceNETosis occurs in stored canine NLR RBC units, and is attenuated by LR before storage. NETs might be mediators of transfusion reactions.

Yttrium-90 radioembolization as a possible new treatment for brain cancer: proof of concept and safety analysis in a canine model

PurposeTo evaluate the safety, feasibility, and preliminary efficacy of yttrium-90 (90Y) radioembolization (RE) as a minimally invasive treatment in a canine model with presumed spontaneous brain cancers.MaterialsThree healthy research dogs (R1–R3) and five patient dogs with spontaneous intra-axial brain masses (P1–P5) underwent cerebral artery RE with 90Y glass microspheres (TheraSphere). 90Y-RE was performed on research dogs from the unilateral internal carotid artery (ICA), middle cerebral artery (MCA), and posterior cerebral artery (PCA) while animals with brain masses were treated from the ICA. Post-treatment 90Y PET/CT was performed along with serial neurological exams by a veterinary neurologist. One month after treatment, research dogs were euthanized and the brains were extracted and sent for microdosimetric and histopathologic analyses. Patient dogs received post-treatment MRI at 1-, 3-, and 6-month intervals with long-term veterinary follow-up.ResultsThe average absorbed dose to treated tissue in R1–R3 was 14.0, 30.9, and 73.2 Gy, respectively, with maximum doses exceeding 1000 Gy. One month after treatment, research dog pathologic analysis revealed no evidence of cortical atrophy and rare foci consistent with chronic infarcts, e.g., < 2-mm diameter. Absorbed doses to masses in P1–P5 were 45.5, 57.6, 58.1, 45.4, and 64.1 Gy while the dose to uninvolved brain tissue was 15.4, 27.6, 19.2, 16.7, and 33.3 G, respectively. Among both research and patient animals, 6 developed acute neurologic deficits following treatment. However, in all surviving dogs, the deficits were transient resolving between 7 and 33 days post-therapy. At 1 month post-therapy, patient animals showed a 24–94% reduction in mass volume with partial response in P1, P3, and P4 at 6 months post-treatment. While P2 initially showed a response, by 5 months, the mass had advanced beyond pre-treatment size, and the dog was euthanized.ConclusionThis proof of concept demonstrates the technical feasibility and safety of 90Y-RE in dogs, while preliminary, initial data on the efficacy of 90Y-RE as a potential treatment for brain cancer is encouraging.

A systematic review of complications related to laparoscopic and laparoscopic-assisted procedures in dogs.

To evaluate and report the quality of the scientific literature reporting complications associated with laparoscopic and laparoscopic-assisted procedures in client-owned or healthy research dogs and to report and illustrate laparoscopic complications related to individual organ systems. Systematic review. Client-owned or healthy research dogs. A literature review was performed by using PubMed and CAB abstracts for English-language studies providing descriptions of complications related to laparoscopic and laparoscopic-assisted procedures in dogs. Study selection used PRISMA (Preferred Reporting Items for Systematic reviews and Meta-Analyses) guidelines. Quality assessment was performed by using a MINORS (Methodological Items for Non-Randomized Studies) scoring system and a grading scale of level of evidence. Descriptive statistics were used. In total, 741 manuscripts were identified, with 64 manuscripts eligible for data extraction and quality assessment. The most represented organ system was the female genital tract, represented by 22 (34.4%) studies. The most commonly reported intraoperative and postoperative complications were related to abdominal entry and portal incisions, respectively. In 53 of 54 non-randomized studies, high risk of bias was found. Forty-eight (75%) studies provided level III or IV evidence. This report provides an updated review of complications related to laparoscopic and laparoscopic-assisted procedures in dogs, classified by organ system. The overall quality of evidence was low, limiting direct comparison of complication rates between studies. There is a need for implementation of standardized criteria for defining complications, study time frames and greater numbers of high quality prospective randomized trials in veterinary laparoscopy to permit comparison of complication and conversion rates between published studies and across organ systems.

Minimally invasive spine surgery in dogs: Evaluation of the safety and feasibility of a thoracolumbar approach to the spinal cord.

To describe the safety and feasibility of a minimally invasive spine surgery technique to access the thoracolumbar vertebral canal in dogs. Prospective study. Six healthy research dogs. Dogs were placed under anesthesia for MRI to evaluate vertebral column and spinal cord integrity. Minimally invasive surgery was performed at multiple sites. Access to the vertebral canal was achieved by means of foraminotomy, discectomy, and lateral minicorpectomy by using minimally invasive access and a surgical microscope. Sequential neurological examinations, pressure algometry pain quantification, and creatine kinase levels were evaluated before and after surgery for 7 days. Magnetic resonance imaging, computed tomography, and histopathology were performed on day 6 postoperatively after animals were humanely killed to evaluate the impact of surgery on spinal cord, muscles, and bone. The vertebral canal was successfully accessed, and the ventral aspect of the spinal cord was identified at all sites. No neurological deterioration was observed. Postoperative pain was not different compared with baseline except in one dog on the day after surgery. Minimally invasive spine surgery was a safe and feasible technique to access the thoracolumbar vertebral canal and the ventral aspect of the spinal cord in dogs. Findings supported postoperative pain benefits. Minimally invasive spine surgery is a valid surgical technique to access the thoracolumbar vertebral canal at single or multiple sites in dogs.

Respiratory dysbiosis and population-wide temporal dynamics in canine chronic bronchitis and non-inflammatory respiratory disease.

The lungs of people and companion animals are now recognized to harbor diverse, low biomass bacterial communities. While these communities are difficult to characterize using culture-based approaches, targeted molecular methods such as 16S rRNA amplicon sequencing can do so using DNA extracted from samples such as bronchoalveolar lavage fluid (BALF). Previous studies identified a surprisingly uniform composition of the microbiota in the lungs of healthy research dogs living in a controlled environment, however there are no reports of the lung microbiota of client-owned dogs. Moreover, compositional changes in the lung microbiota depending on disease status have been reported in people, suggesting that similar events may occur in dogs, a species subject to several respiratory disease mechanisms analogous to those seen in people. To address these knowledge gaps, BALF samples from client-owned dogs presenting to the University of Missouri Veterinary Health Center for respiratory signs between 2014 and 2017 were processed for and subjected to 16S rRNA sequencing. Based on specific diagnostic criteria, dogs were categorized as Chronic Bronchitis (CB, n = 53) or non-CB (n = 11). Community structure was compared between groups, as well as to historical data from healthy research dogs (n = 16) of a uniform breed and environment. The lung microbiota detected in all client-owned dogs was markedly different in composition from that previously detected in research dogs and contained increased relative abundance of multiple canine fecal and environmental bacteria, likely due to aspiration associated with their clinical signs. While inter-sample diversity differed significantly between samples from CB and non-CB dogs, the variability within both groups made it difficult to discern reproducible bacterial classifiers of disease. During subsequent analyses to identify other sources of variability within the data however, population-wide temporal dynamics in community structure were observed, with substantial changes occurring in late 2015 and again in early 2017. A review of regional climate data indicated that the first change occurred during a historically warm and wet period, suggesting that changes in environmental conditions may be associated with changes in the respiratory microbiota in the context of respiratory disease. As the lung microbiota in humans and other animals is believed to result from repetitive micro-aspirations during health and in certain disease states associated with dyspnea and laryngeal dysfunction, these data support the increased colonization of the lower airways during compromised airway function, and the potential for temporal effects due to putative factors such as climate.

Clinical, clinicopathologic, and gastrointestinal changes from aspirin, prednisone, or combination treatment in healthy research dogs: A double-blind randomized trial.

BackgroundDogs with immune‐mediated disease are often coadministered glucocorticoids and aspirin, but ulcerogenic effects of current protocols are unknown.ObjectivesTo compare gastrointestinal changes among dogs administered aspirin, prednisone, and combination treatment.AnimalsTwenty‐four healthy research dogs.MethodsDouble‐blinded, placebo‐controlled randomized trial of dogs administered placebo, aspirin (2 mg/kg q24h), prednisone (2 mg/kg q24h), or combination treatment PO for 28 days. Clinical signs were recorded daily, with laboratory work performed at baseline and day 28. Gastrointestinal mucosal hemorrhages, erosions, and ulcers were numerated for endoscopic studies performed on days 0, 14, and 28; endoscopic mucosal lesion scores were calculated. Results were compared using mixed model repeated‐measures analyses of variance and generalized estimating equation proportional odds models. P < .05 was considered significant.ResultsGastric mucosal lesion scores differed by treatment‐by‐time (F[6, 40] = 4.4, P = .002), treatment (F[3, 20] = 7.1, P = .002), and time (F[2, 40] = 18.9, P < .001). Post hoc analysis revealed increased scores in the aspirin (day 14 only), prednisone, and prednisone/aspirin groups during treatment. Ulcers were identified on 14 studies, representing 10 dogs. Dogs receiving prednisone and prednisone/aspirin had 11.1 times (95% CI, 1.7‐73.6) and 31.5 times (95% CI, 3.5‐288.0) higher odds, respectively, of having endoscopic mucosal lesion scores ≥4 than dogs receiving placebo (P ≤ .01).Conclusions and Clinical ImportanceGastrointestinal bleeding occurs commonly in dogs administered aspirin, prednisone, or prednisone/aspirin treatment, with higher lesion scores for dogs receiving combination treatment. Even severe lesions are not accompanied by clinical signs.

Comparison of the effects of different kibble shape on voluntary food intake and palatability of weight loss diets in pet dogs

Altering characteristics of a dry proprietary diet can increase chewing, slow ingestion speed and reduce voluntary food intake. Panels of healthy research dogs consumed kibbled weight loss diets with either a l round (pastille) or a cross shape. Two panels (‘small-size’ panel, dogs<10 kg ‘all-size’ panel, dogs with a range of sizes) were used to determine palatability (study 1), whilst a third panel (‘consumption kinetics panel’) was used to determine voluntary food intake [VFI] and meal duration (study 2). Study 3 was a field trial where the cross kibble was fed to client-owned overweight dogs undergoing controlled weight loss, and attitudes of owners were sort. In study 1, dogs in the all-size panel consumed more of the cross-kibble diet than of the round-kibble diet (P < .001), but there was no significant difference in dogs of the small-size panel (P = 1.000). In study 2, VFI was broadly similar for both diets, with no difference in total consumption across all four meals (P = .370). However, meal duration was significantly longer for the cross kibble (meal 1: 292 s; meal 2: 650 s) compared with the round kibble (meal 1: 186 s; meal 2: 282, P < .001 for both). In study 3, owners observed more chewing behaviour (P = .031), slower ingestion speed (P = .031), and a significant decrease in food-seeking behaviour (P = .020) when eating the cross-kibble compared with the round-kibble. Altering the kibble shape of a canine therapeutic weight loss diet can decrease ingestion speed without affecting palatability, but studies are now required to determine the effect on outcomes of weight management.

Testing for food-specific antibodies in saliva and blood of food allergic and healthy dogs

An elimination diet (ED) followed by re-challenge has been the reference standard to diagnose adverse food reactions (AFR) in dogs, but can be challenging to conduct. This study investigated the accuracy of a saliva-based test for food-specific IgA and IgM and an ELISA serum test for food-specific IgE. Three groups of dogs were tested. Group 1 (n=11) included dogs with previously diagnosed and controlled AFR; group 2 (n=15) comprised dogs with allergic dermatitis at the beginning of their ED; and group 3 (n=16) was composed of clinically healthy research dogs. Saliva samples were collected from all groups and blood samples from group 1 and group 3. The results of clinical re-challenges with individual food components were compared with the test results. Specificity, sensitivity, positive and negative predictive values and likelihood ratios were determined.Forty-one dogs completed the study; one dog was lost to follow up. There was a total of 163 re-challenges. Sensitivity, positive predictive value and likelihood ratio, specificity, negative predictive value and likelihood ratios were unsatisfactory for both tests in most instances, except for IgM testing in group 2, which had moderate specificity. There was no clear difference in the number of positive reactions between the allergic dogs and healthy dogs from a research population. Based on these results, the saliva test for food specific IgA and IgM and the ELISA serum test for food specific IgE were not reliable to diagnose adverse food reactions in dogs. Until more data are available, elimination diets remain the reference standard in the diagnosis of this disease.

Evaluation of the Live Biotherapeutic Product, Asymptomatic Bacteriuria Escherichia coli 2-12, in Healthy Dogs and Dogs with Clinical Recurrent UTI.

BackgroundAntimicrobial resistance is an emerging problem.Hypothesis/ObjectiveTo investigate the safety and efficacy of a live biotherapeutic product, ASB E. coli 2‐12 for UTI treatment.AnimalsSix healthy research dogs; nine client‐owned dogs with recurrent UTI.MethodsProspective noncontrolled clinical trial. For safety data, research dogs were sedated, a urinary catheter was inserted into the bladder; 1010 CFU/mL of ASB E. coli 2‐12 was instilled. Urine was cultured on days 1, 3, and 8 post‐instillation and dogs were observed for lower urinary tract signs (LUTS). For client‐owned dogs, ASB E. coli 2‐12 was instilled similarly and urine cultures analyzed on days 1, 7, and 14 days postinstillation.ResultsNo LUTS were noted in any of the 6 research dogs after ASB E. coli 2‐12 infusion. Pulse field gel electrophoresis (PFGE) studies confirmed the bacterial strains isolated matched that ASB E. coli 2‐12 strain. Four of the nine client‐owned dogs had complete or nearly complete clinical cures by day 14. Of these four dogs, 3 also had microbiologic cures at day 14; one of these dogs had subclinical bacteriuria (in addition to ASB E. coli 2‐12). Three of these four dogs had ASB E. coli 2‐12 isolated from their urine at day 14. With the exception of mild, temporary, self‐limiting, hyporexia in two dogs on the day of biotherapeutic administration, there were no major adverse effects.Conclusions and Clinical ImportanceThese results suggest ASB E. coli 2‐12 is safe and should be investigated in a larger controlled study evaluating clinical UTI in dogs.

Computed tomographic assessment of sternal lymph node dimensions and attenuation in healthy dogs

OBJECTIVE To assess dimensions and attenuation of sternal lymph nodes (SLNs) observed by means of CT in healthy dogs. ANIMALS 12 healthy adult research dogs. PROCEDURES Precontrast and postcontrast enhanced CT of the thorax was performed on each dog. Objective and subjective contrast-enhanced CT measurements were obtained. RESULTS By use of CT, 2 SLNs were identified in 10 of the 12 dogs and 1 SLN was identified in 2. Median SLN length, height, and width were 8.5 mm (range, 4 to 22 mm), 6.0 mm (range, 3 to 10 mm), and 5.0 mm (range, 3 to 10 mm), respectively. Median SLN length-to-T4 ratio, height-to-T4 ratio, and width-to-T4 ratio were 0.64 (range, 0.24 to 1.22), 0.37 (range, 0.25 to 0.53), and 0.29 (range, 0.19 to 0.67), respectively. Median SLN volume was 123 mm3 (range, 38 to 484 mm3). Median height-to-length ratio, width-to-length ratio, and height-to-width ratio were 0.57 (range, 0.27 to 1.75), 0.51 (range, 0.31 to 1.25), and 1.27 (range, 0.50 to 2.50), respectively. All SLNs had homogenous contrast enhancement with median precontrast and postcontrast attenuation values of 18.3 Hounsfield units (HU; range, 4.4 to 36.9 HU) and 41.3 HU (range, 24.0 to 77.4 HU), respectively. All SLNs had a visible hilus, which was fat attenuating in 8 dogs and hypoattenuating in 4 dogs. CONCLUSIONS AND CLINICAL RELEVANCE CT imaging characteristics described in this study may provide a reference for dimensions and appearance of SLNs of healthy dogs and serve as a basis for comparison with results for diseased dogs.

Applicability of 99m Tc-Labeled Human Serum Albumin Scintigraphy in Dogs With Protein-Losing Enteropathy.

BackgroundDiagnosis of protein loss into the gastrointestinal tract using noninvasive techniques is challenging. In people, scintigraphy not only is a sensitive tool to confirm protein‐losing enteropathy (PLE), but it also allows for localization of protein loss.Hypothesis/ObjectivesTo investigate the feasibility of 99mTc‐labeled human serum albumin (HSA) scintigraphy in dogs with PLE in comparison with control dogs.AnimalsA total of 8 clinically healthy control research dogs and 7 client‐owned dogs with gastrointestinal clinical signs and hypoalbuminemia (serum albumin concentration <2.0 g/dL).MethodsProspective case–control study. After IV injection of 400 MBq freshly prepared 99mTc HSA (30 mg/dog), images of the abdomen were obtained 10, 60, 120, and 240 minutes postinjection. Additional images of the salivary and thyroid glands were obtained to rule out free 99mTc. A scan was considered positive for PLE when radiopharmaceutical exudation was detectable in the intestinal tract.ResultsOnly 1 control dog showed exudation of the radiopharmaceutical into the intestinal tract. No free 99mTc was detected in any dog. In dogs with PLE, focal small intestinal and diffuse small intestinal radiopharmaceutical exudation into the bowel was detected in 2 and 3 dogs, respectively, whereas in 2 dogs, there was disagreement about whether radiopharmaceutical exudation was focal or diffuse.Conclusion and Clinical Importance 99mTc‐labeled HSA scintigraphy was feasible to diagnose PLE in dogs.

Effect of feeding on the pharmacokinetics of oral minocycline in healthy research dogs.

The effect of food on minocycline oral absorption in dogs is unknown. The objective was to determine the pharmacokinetics of minocycline after administration of a single oral dose in fed and fasted dogs. Ten research hounds were administered oral minocycline (approximately 5 mg/kg) with and without food, in a crossover study, with a one-week wash-out between treatments. Blood samples were collected immediately prior to minocycline administration and over 24 h. Minocycline plasma drug concentrations were measured using high-performance liquid chromatography using ultraviolet detection and were analysed with compartmental modelling to determine primary pharmacokinetic parameters. Each dog was analysed independently, followed by calculation of means and variation of the dogs. The Wilcoxon signed-rank test [analysing secondary pharmacokinetic parameters - peak concentration (CMAX ), area under the concentration versus time curve (AUC)] was used to compare the two groups. A population pharmacokinetic modelling approach was performed using nonlinear mixed effects modelling of primary parameters for the population as fixed effects and the difference between subjects as a random effect. Covariate analysis was used to identify the source of variability in the population. No significant difference was found between treatments for AUC (P = 0.0645), although AUC was higher in fasted dogs. A significant difference was found for CMAX (P = 0.0059), with fasted dogs attaining a higher CMAX . The covariate of fed versus fasted accounted for a significant variation in the pharmacokinetics. Because feeding was a significant source of variation for the population's primary pharmacokinetic parameters and fasted dogs had higher minocycline concentrations, we recommend administering minocycline without food.

Comparison of concentrations of γ-aminobutyric acid and glutamate in cerebrospinal fluid of dogs with idiopathic epilepsy with and without seizure-related magnetic resonance imaging hyperintense areas in the limbic system

To investigate differences in CSF concentrations of excitatory and inhibitory neurotransmitters in dogs with and without T2-weighted (T2W) MRI hyperintense areas in the limbic system. Archived CSF samples and stored brain MRI images of 5 healthy research dogs (group 1), 8 dogs with idiopathic epilepsy (IE) with no abnormal MRI findings (group 2), and 4 dogs with IE with hyperintense areas in the limbic system detected by means of T2W MRI (group 3). Archived CSF samples and stored MRI images obtained from all dogs were evaluated. Dogs in groups 2 and 3 were matched on the basis of age and breed. High-performance liquid chromatography was used to evaluate glutamate and γ-aminobutyric acid (GABA) concentrations in CSF samples. Glutamate concentrations were higher in CSF of both groups of dogs with IE than in healthy dogs. However, glutamate concentrations in CSF were not significantly higher in dogs with IE and with hyperintense areas than in dogs with IE but no abnormal MRI findings. Concentrations of GABA in CSF were higher in group 3 than in group 2 and in group 2 than in group 1. No significant difference was evident between glutamate concentrations in CSF of dogs with IE and with and without hyperintense areas detected by means of T2W MRI. However, glutamate concentrations typically were higher in CSF of dogs with IE and MRI hyperintense areas. Future studies with larger sample sizes should be conducted to confirm this finding and to determine the clinical importance of high glutamate concentrations in CSF of dogs with IE.

Transfusion of 28‐day‐old leucoreduced or non‐leucoreduced stored red blood cells induces an inflammatory response in healthy dogs

Studies in mice suggest that rapid transfusions of red blood cells (RBCs), refrigerator stored for longer durations, induce a pro-inflammatory cytokine response. Studies in human neonates confirm these findings; however, to date, adult human studies have failed to replicate these findings. We used healthy research dogs to begin to examine the factors affecting the cytokine response to transfusion. In a prospective study, healthy dogs were randomized for two autologous packed RBC transfusions after 7 (i.e. 'fresh') and 28 (i.e. 'old') days of storage, or after 28 and 7days of storage, with or without prestorage leucoreduction (LR). No significant differences were observed between LR and non-LR transfusions for all circulating analytes measured following transfusion. A pro-inflammatory cytokine response, exemplified by monocyte chemoattractant protein-1, was observed 6h after only old RBC transfusions, irrespective of infusion rate (P<0·001). This response was accompanied by increased neutrophil counts (P<0·001) and decreased platelet counts (P<0·001). In healthy dogs, old RBC transfusions induce inflammation, which is unaffected by infusion rate.