OBJECTIVE To evaluate the effects of granulocyte colony–stimulating factor (GCSF) administration in dogs with experimentally induced acute kidney injury. ANIMALS 6 healthy dogs. PROCEDURES After induction of kidney injury (day 0) with cisplatin (5 mg/kg, IV), the dogs were randomly assigned into 2 groups (n = 3 dogs/group). Then dogs immediately received GCSF (10 μg/kg) or 1 mL of saline (0.9% NaCl) solution (control group) SC; this treatment was repeated once daily for 4 additional days (days 1 through 4). A once-daily CBC (day 0 to 4), serum biochemical analysis (day 0 to 3), and urinalysis (day 0 to 3) were performed for each dog; samples were collected before administration of cisplatin (day 0) and before treatment with GCSF or saline solution (days 1 through 4). After sample collection and treatment on day 4, all dogs were euthanized; kidney tissue samples underwent histologic evaluation, immunohistochemical analyses, and cytokine profiling via reverse transcriptase PCR assay. RESULTS In the GCSF-treated group, the histologic evaluation and immunohistochemical analyses of kidney tissue revealed less fibrotic change and greater proliferation of renal tubular epithelial cells, compared with findings in the control group. The mRNA profiles of kidney tissue from the GCSF-treated group indicated lower expression of tumor necrosis factor-α and tumor growth factor-β, compared with findings in the control group; however, concentrations of factors related to renal regeneration were not greater in the GCSF-treated group. CONCLUSIONS AND CLINICAL RELEVANCE Results indicated that GCSF treatment can impede renal fibrosis and increase proliferation of renal tubules after experimentally induced acute kidney injury in dogs.

OBJECTIVE To evaluate the correlation coefficient of the ratio between diameter of the caudal vena cava (CVC) and diameter of the aorta (Ao) in dogs as determined ultrasonographically with systolic pressure variation (SPV). ANIMALS 14 client-owned dogs (9 females and 5 males; mean ± SD age, 73 ± 40 months; mean body weight, 22 ± 7 kg) that underwent anesthesia for repair of skin wounds. PROCEDURES Anesthesia was induced. Controlled mechanical ventilation with a peak inspiratory pressure of 8 cm H2O was immediately started, and SPV was measured. During a brief period of suspension of ventilation, CVC-to-Ao ratio was measured on a transverse right-lateral intercostal ultrasonographic image obtained at the level of the porta hepatis. When the SPV was ≥ 4 mm Hg, at least 1 bolus (3 to 4 mL/kg) of Hartmann solution was administered IV during a 1-minute period. Bolus administration was stopped and the CVC-to-Ao ratio measured when SPV was < 4 mm Hg. Correlation coefficient analysis was performed. RESULTS 28 measurements were obtained. The correlation coefficient was 0.86 (95% confidence interval, 0.72 to 0.93). Mean ± SD SPV and CVC-to-Ao ratio before bolus administration were 7 ± 2 mm Hg and 0.52 ± 0.16, respectively. Mean ± SD SPV and CVC-to-Ao ratio after bolus administration were 2 ± 0.6 mm Hg and 0.91 ± 0.13, respectively. CONCLUSIONS AND CLINICAL RELEVANCE In this study, the CVC-to-Ao ratio was a feasible, noninvasive ultrasonographically determined value that correlated well with SPV.

OBJECTIVE To characterize the elution of platinum from carboplatin-impregnated calcium sulfate hemihydrate (CSH) beads in vitro. SAMPLE 60 carboplatin-impregnated CSH beads and 9 CSH beads without added carboplatin (controls). PROCEDURES Carboplatin-impregnated CSH beads (each containing 4.6 mg of carboplatin [2.4 mg of platinum]) were placed into separate 10-mL plastic tubes containing 5 mL of PBSS in groups of 1, 3, 6, or 10; 3 control beads were placed into a single tube of PBSS at the same volume. Experiments were conducted in triplicate at 37°C and a pH of 7.4 with constant agitation. Eluent samples were collected at 1, 2, 3, 6, 12, 24, and 72 hours. Samples were analyzed for platinum content by inductively coupled plasma–mass spectrometry. RESULTS The mean concentration of platinum released per carboplatin-impregnated bead over 72 hours was 445.3 mg/L. Cumulative concentrations of platinum eluted increased as the number of beads per tube increased. There was a significant difference in platinum concentrations over time, with values increasing over the first 12 hours and then declining for all tubes. There was also a significant difference in percentage of total incorporated platinum released into tubes with different numbers of beads: the percentage of eluted platinum was higher in tubes containing 1 or 3 beads than in those containing 6 or 10 beads. CONCLUSIONS AND CLINICAL RELEVANCE Carboplatin-impregnated CSH beads eluted platinum over 72 hours. Further studies are needed to determine whether implantation of carboplatin-impregnated CSH beads results in detectable levels of platinum systemically and whether the platinum concentrations eluted locally are toxic to tumor cells.

OBJECTIVE To investigate the effects of specific cysteine protease (CP) inhibitors on cytopathic changes to porcine intestinal epithelial cells induced by Tritrichomonas foetus isolated from naturally infected cats. SAMPLE T foetus isolates from 4 naturally infected cats and nontransformed porcine intestinal epithelial cells. PROCEDURES T foetus isolates were treated with or without 0.1 to 1.0mM of the CP inhibitors antipain, cystatin, leupeptin, and chymostatin and the vinyl sulfone inhibitors WRR-483 and K11777. In-gel gelatin zymography was performed to evaluate the effects of these inhibitors on CP activity of T foetus isolates. Each treated or untreated isolate was also cocultured with monolayers of porcine intestinal epithelial cells for 24 hours, and cytopathic effects of T foetus were evaluated by light microscopy and crystal violet spectrophotometry. RESULTS Results of in-gel gelatin zymography suggested an ability of WRR-483, K11777, and cystatin to target specific zones of CP activity of the T foetus isolates. These inhibitors had no effect on T foetus growth, and the cytopathic changes to the intestinal epithelium induced by all 4 T foetus isolates were significantly inhibited. CONCLUSIONS AND CLINICAL RELEVANCE This study revealed that certain protease inhibitors were capable of inhibiting regions of CP activity (which has been suggested to cause intestinal cell damage in cats) in T foetus organisms and of ameliorating T foetus–induced cytopathic changes to porcine intestinal epithelium in vitro. Although additional research is needed, these inhibitors might be useful in the treatment of cats with trichomonosis.

OBJECTIVE To investigate the in vitro stability of atrial natriuretic peptide (ANP) in plasma samples under various storage conditions and the influence of anesthesia on plasma ANP concentration in cats. ANIMALS 1 cat with congestive heart failure and 5 healthy adult mixed-breed cats. PROCEDURES A plasma sample from the cat with heart failure was serially diluted, and dilutional parallelism of ANP concentration was evaluated. Plasma samples containing aprotinin or serum samples from the 5 healthy cats were kept at room temperature (27°C) for ≤ 12 hours. Plasma samples from the same healthy cats were stored at −70°, −20°, or 4°C for ≤ 14 days. Plasma samples were obtained from the healthy cats before and during isoflurane anesthesia. Plasma ANP concentrations were measured at a commercial laboratory by use of a human ANP chemiluminescence assay. RESULTS Intra- and interassay coefficients of variation were 1.5% and 2.5%, respectively, and dilutional parallelism was established. Although ANP concentration decreased by 82.4 ± 13.6% (mean ± SD) after sample storage for 12 hours at room temperature, this decrease was prevented by aprotinin. Plasma ANP concentrations were stable for 7 days at −20°C and for 14 days at −70°C. However, concentrations decreased markedly to 57.6 ± 6.9% at −20°C and to 18.0 ± 3.0% at 4°C after 14 days. Plasma ANP concentration decreased significantly in cats during anesthesia and was correlated with blood pressure. CONCLUSIONS AND CLINICAL RELEVANCE Results suggested that aprotinin should be added routinely in preparation of plasma samples from cats for measurement of ANP concentration, and those samples, if stored, should be frozen immediately at ≤ −20°C. General anesthesia or systemic blood pressure may affect plasma ANP concentration in cats.

The objective of this study was to describe the association between thermal measures in the barn environment (pen temperature and humidity) and fecal shedding of Salmonella in dairy cattle. A repeated cross-sectional study was conducted within a commercial dairy herd located in the midwestern United States. Five pooled fecal samples were collected monthly from each pen for 9 mo and submitted for microbiological culture. Negative binomial regression methods were used to test the association [incidence rate ratio (IRR)] between Salmonella pen status (the count of Salmonella-positive pools) and thermal environmental parameters [average temperature and temperature humidity index (THI)] for 3 time periods (48 h, 72 h, and 1 wk) before fecal sampling. Salmonella was cultured from 10.8% [39/360; 95% confidence interval (CI): 7.8% to 14.5%] of pooled samples. The highest proportion of positive pools occurred in August. The IRR ranged from 1.26 (95% CI: 1.15 to 1.39, THI 1 wk) to 4.5 (95% CI: 2.13 to 9.51, heat exposure 1 wk) across all thermal parameters and lag time periods measured. For example, the incidence rate of Salmonella-positive pools increased by 54% for every 5°C increment in average temperature (IRR = 1.54; 95% CI: 1.29 to 1.85) and 29% for every 5-unit increase in THI (IRR = 1.29; 95% CI: 1.16 to 1.42) during the 72 h before sampling. The incidence rate ratio for pens exposed to higher temperatures (> 25°C) was 4.5 times (95% CI: 2.13 to 9.51) the incidence rate ratio for pens exposed to temperatures < 25°C in the 72 h before sampling. Likewise, the incidence rate ratio for pens exposed to THI > 70 was 4.23 times greater (95% CI: 2.1 to 8.28) than when the THI was < 70 in the 72 h before sampling. An association was found between the thermal environment and Salmonella shedding in dairy cattle. Further research is warranted in order to fully understand the component risks associated with the summer season and increased Salmonella shedding.

OBJECTIVE To determine effects of catheter shape, interelectrode spacing (IS), and electrode size (ES) on pacing threshold (PT), extraneous muscular stimulation (EMS), and zone of capture (ZOC) for dogs undergoing transesophageal atrial pacing (TAP). ANIMALS 10 purpose-bred dogs without cardiac conduction disturbances. PROCEDURES 7 configurations for TAP catheters were tested in each dog to evaluate effects of catheter shape (curved or straight), IS (5, 15, and 25 mm), and ES (2, 4, and 6 mm). Each catheter was passed into the esophagus to a location aboral to the heart and slowly withdrawn until atrial pacing was achieved. Then, catheters were withdrawn in 5-mm increments until pacing could not be achieved. Outcomes measured at each pacing site included PT, degree of EMS, and ZOC. RESULTS There was a significantly lower PT, wider ZOC, and less EMS for the curved catheter than for the straight catheter. An ES of 6 mm induced significantly more EMS than was induced by an ES of 2 or 4 mm. An IS of 5 mm induced significantly less EMS and a significantly narrower ZOC but required a significantly higher PT, compared with results for an ES of 15 or 25 mm. Additionally, there was a significant direct correlation between IS and ZOC. CONCLUSIONS AND CLINICAL RELEVANCE Results indicated that a curved catheter with multiple 4-mm electrodes that provides for variable IS would be ideal for TAP in dogs. IMPACT FOR HUMAN MEDICINE TAP catheters currently used in human medicine are straight. The PT in humans may potentially be reduced with curved catheters.

OBJECTIVE To evaluate circadian and postprandial variations in plasma citrulline concentration in healthy dogs. ANIMALS 8 healthy Beagles. PROCEDURES Blood samples were collected from dogs after 12 hours of food withholding (0 hours; 8:00 am) and then every 2 hours for 12 hours (until 8:00 pm) and again at 24 hours (8:00 am the next day). The same protocol was repeated, with the only difference being that a meal was given immediately after the 0-hour sample collection point. Plasma citrulline concentration was measured by ion exchange chromatography. RESULTS No significant difference in plasma citrulline concentration was identified among measurement points when food was withheld. Mean ± SD plasma citrulline concentration at 4 hours (72.2 ± 12.7 μmol/L) and 24 hours (56.1 ± 12.5 μmol/L) after dogs were fed was significantly different from that at 0 hours (64.4 ± 12.7 μmol/L). CONCLUSIONS AND CLINICAL RELEVANCE Plasma citrulline concentration had no circadian variation in unfed dogs but increased significantly in fed dogs 4 hours after a meal. Therefore, food should be withheld from dogs for 8 to 12 hours before blood sample collection for measurement of citrulline concentration.

OBJECTIVE To assess feasibility of flexible endoscopic evaluation of swallowing (FEES) in awake dogs, determine whether specific variables associated with the oropharyngeal phase of swallowing can be recognized, and evaluate the safety and tolerability of FEES. ANIMALS 6 healthy client-owned large- and giant-breed adult dogs. PROCEDURES A topical anesthetic was applied to the nasal passage of each dog, and a fiberoptic endoscope was passed transnasally until the tip of the scope was positioned in the oropharynx. All dogs voluntarily drank colored water followed by consumption of a commercial canned diet and then a kibble diet mixed with food color. During each swallow, laryngeal and pharyngeal anatomic structures were evaluated and depth of bolus flow prior to the pharyngeal phase of swallowing was assessed. Evidence of bolus retention in the vallecula or pyriform sinuses and laryngeal penetration of the bolus were recorded. RESULTS FEES was completed without major adverse events and was tolerated well by all 6 dogs. Mild, self-limiting epistaxis was noted for 2 dogs. The nasopharynx, oropharynx, and hypopharynx were observed in all dogs; movement of food boluses through the esophagus was observed in 2 dogs, and food boluses in the stomach were visible in 1 dog. Pharyngeal and laryngeal function was considered physiologically normal in all dogs. CONCLUSIONS AND CLINICAL RELEVANCE FEES appeared to be a feasible diagnostic tool for use in large- and giant-breed dogs. Studies are warranted in dogs with oropharyngeal dysphagia to determine whether FEES can be tolerated and whether it can augment videofluoroscopy findings.

OBJECTIVE To compare expression, activity, and fecal concentration of intestinal alkaline phosphatase (IAP) between healthy dogs and dogs with chronic enteropathy (CE). ANIMALS 9 healthy university-owned Beagles and 109 healthy client-owned dogs (controls) and 28 dogs with CE (cases). PROCEDURES Cases were defined as dogs with persistent (> 3 weeks) gastrointestinal signs that failed to respond to antimicrobials and anti-inflammatory doses of prednisolone or dietary trials, did not have mechanical gastrointestinal abnormalities as determined by abdominal radiography and ultrasonography, and had a diagnosis of lymphoplasmacytic enteritis or eosinophilic gastroenteritis on histologic examination of biopsy specimens. Duodenal and colonic mucosa biopsy specimens were obtained from the 9 university-owned Beagles and all cases for histologic examination and determination of IAP expression (by real-time quantitative PCR assay) and activity (by enzyme histochemical analysis). Fecal samples were obtained from all dogs for determination of fecal IAP concentration by a quantitative enzyme reaction assay. RESULTS For dogs evaluated, IAP expression and activity were localized at the luminal side of epithelial cells in the mucosa and intestinal crypts, although both were greater in the duodenum than in the colon. Active IAP was detected in the feces of all dogs. Intestinal alkaline phosphatase expression and activity were lower for cases than for controls, and fecal IAP concentration for dogs with moderate and severe CE was lower than that for dogs with mild CE. CONCLUSIONS AND CLINICAL RELEVANCE Results indicated that dogs with CE had impaired IAP expression and activity. Additional research is necessary to elucidate the role of IAP in the pathogenesis of CE.