Evaluation of endoscopically obtained duodenal biopsy samples from cats and dogs in an adapter-modified Ussing chamber.

This study was conducted to evaluate an adapter-modified Ussing chamber for assessment of transport physiology in endoscopically obtained duodenal biopsies from healthy cats and dogs, as well as dogs with chronic enteropathies. 17 duodenal biopsies from five cats and 51 duodenal biopsies from 13 dogs were obtained. Samples were transferred into an adapter-modified Ussing chamber and sequentially exposed to various absorbagogues and secretagogues. Overall, 78.6% of duodenal samples obtained from cats responded to at least one compound. In duodenal biopsies obtained from dogs, the rate of overall response ranged from 87.5% (healthy individuals; n = 8), to 63.6% (animals exhibiting clinical signs of gastrointestinal disease and histopathological unremarkable duodenum; n = 15), and 32.1% (animals exhibiting clinical signs of gastrointestinal diseases and moderate to severe histopathological lesions; n = 28). Detailed information regarding the magnitude and duration of the response are provided. The adapter-modified Ussing chamber enables investigation of the absorptive and secretory capacity of endoscopically obtained duodenal biopsies from cats and dogs and has the potential to become a valuable research tool. The response of samples was correlated with histopathological findings.

Adapter-modified Ussing chamber enables evaluation of endoscopically-obtained colonic biopsy samples from cats and dogs.

Adapter-modified Ussing chambers have been used for assessment of endoscopically obtained intestinal biopsies in humans. The aim of this study was to evaluate the feasibility of an adapter-modified Ussing chamber for assessment of intestinal transport physiology in endoscopically-obtained colonic biopsies from cats and dogs. Fifteen colonic biopsies from four cats and 13 colonic biopsies from four dogs were transferred into a modified Ussing chamber and sequentially exposed to several compounds. Baseline mean±SD conductance was measured. Changes of short circuit current (ΔIsc) were observed after exposure to glucose (number of feline biopsies that responded=0/number of canine biopsies that responded=4), phloridzin (n=0/n=7), histamine (n=5/n=12), serotonin (n=7/n=12), prostaglandin (n=5/n=7), forskolin (n=7/n=7), and ouabain (n=9/n=7). The adapter-modified Ussing chamber studied here enables investigation of transport physiology of endoscopically-obtained colonic biopsies from companion animals. However, we observed a large variability of results, suggesting that clinical use of this method is limited.

Optimization of sample handling and processing for the carbon 13-labeled aminopyrine demethylation blood test and determination of a reference range for test results in healthy dogs.

OBJECTIVE: To determine the optimal sample handling and processing conditions for the carbon 13 ((13)C)-labeled aminopyrine demethylation blood test (ADBT; phase 1) and determine the reference range for test results (phase 2) in apparently healthy dogs. ANIMALS: 44 apparently healthy dogs (phase 1, 19 dogs; phase 2, 44 dogs). PROCEDURES: In phase 1, a blood sample from each dog was collected before and 45 minutes after (day 0) IV administration of (13)C-labeled aminopyrine (2 mg/kg); aliquots were immediately transferred into tubes containing sodium heparin and hydrochloric acid (samples A and B), sodium heparin alone (samples C, D, and E), or sodium fluoride (sample F). Hydrochloric acid was added to samples C through F at days 7, 14, 21, and 21, respectively. The baseline and 45-minute samples' absolute (13)C:(12)C ratios were determined via fractional mass spectrometry on day 0 (control sample A) or 21 (samples B through F) and used to calculate the percentage dose of (13)C recovered in CO(2) extracted from samples (PCD). In phase 2, blood samples from each dog were collected into tubes containing sodium fluoride and processed within 3 weeks. RESULTS: Compared with the control sample value, PCDs for samples C through E differed significantly, whereas PCD in sample F did not. The (13)C-ADBT-derived PCD reference range (central 95th percentile) for apparently healthy dogs was 0.08% to 0.2%. CONCLUSIONS AND CLINICAL RELEVANCE: Glycolytic CO(2) production in canine blood samples collected during (13)C-ADBTs was sufficiently inhibited by sodium fluoride to allow delayed sample analysis and avoid transportation of hydrochloric acid-treated samples.