OBJECTIVE To compare the effects of 3 equimolar concentrations of methylprednisolone acetate (MPA), triamcinolone acetonide (TA), and isoflupredone acetate (IPA) on equine articular tissue cocultures in an inflammatory environment. SAMPLE Synovial and osteochondral explants from the femoropatellar joints of 6 equine cadavers (age, 2 to 11 years) without evidence of musculoskeletal disease. PROCEDURES From each cadaver, synovial and osteochondral explants were harvested from 1 femoropatellar joint to create cocultures. Cocultures were incubated for 96 hours with (positive control) or without (negative control) interleukin (IL)-1β (10 ng/mL) or with IL-1β and MPA, TA, or IPA at a concentration of 10(−4), 10(−7), or 10(−10)M. Culture medium samples were collected from each coculture after 48 and 96 hours of incubation. Concentrations of prostaglandin E2, matrix metalloproteinase-13, lactate dehydrogenase, and glycosaminoglycan were determined and compared among treatments at each time. RESULTS In general, low concentrations (10(−7) and 10(−10)M) of MPA, TA, and IPA mitigated the inflammatory and catabolic (as determined by prostaglandin E2 and matrix metalloproteinase-13 quantification, respectively) effects of IL-1β in cocultures to a greater extent than the high (10(−4)M) concentration. Mean culture medium lactate dehydrogenase concentration for the 10(−4)M IPA treatment was significantly greater than that for the positive control at both times, which was suggestive of cytotoxicosis. Mean culture medium glycosaminoglycan concentration did not differ significantly. CONCLUSIONS AND CLINICAL RELEVANCE Results indicated that the in vitro effects of IPA and MPA were similar to those of TA at clinically relevant concentrations (10(−7) and 10(−10)M).

The H9N2 strains of avian influenza viruses (AIVs) circulate worldwide in poultry and cause sporadic infection in humans. To better understand the evolution of these viruses while circulating in poultry, an H9N2 chicken isolate was passaged 19 times in chickens via aerosol inoculation. Whole-genome sequencing showed that the viruses from the initial stock and those after the 8th and 19th passages (P0, P8, and P19) all had the same monobasic cleavage site in the hemagglutinin (HA), typical for viruses of low pathogenicity. However, at position 226 of the HA protein the ratio of glutamine (which favors avian-type receptor binding) to leucine (which favors mammalian-type receptor binding) decreased from 54:46 in P0, to 87:13 in P8, and then 0:100 in P19. In chickens exposed to aerosols of P0, P8, or P19, replication of the viruses was similar and mainly limited to the respiratory tract. None of the infected chickens showed any clinical signs. Over the 19 passages the viruses maintained relatively stable infectivity but gradually lost lethality to chicken embryos. According to the hemagglutination inactivation assay, P8 was slightly and P19 significantly (P < 0.05) less thermostable than P0. Collectively, after 19 passages in chickens the H9N2 AIVs retained low pathogenicity with a positive selection of L226 in the HA. These findings suggest that H9N2 viruses might acquire mammalian specificity after asymptomatic circulation in avian species.

OBJECTIVE To measure effects of oral Akkermansia muciniphila administration on systemic markers of gastrointestinal permeability and epithelial damage following antimicrobial administration in dogs. ANIMALS 8 healthy adult dogs. PROCEDURES Dogs were randomly assigned to receive either A muciniphila (109 cells/kg; n = 4) or vehicle (PBS solution; 4) for 6 days following metronidazole administration (12.5 mg/kg, PO, q 12 h for 7 d). After a 20-day washout period, the same dogs received the alternate treatment. After another washout period, experiments were repeated with amoxicillin-clavulanate (13.5 mg/kg, PO, q 12 h) instead of metronidazole. Fecal consistency was scored, a quantitative real-time PCR assay for A muciniphila in feces was performed, and plasma concentrations of cytokeratin-18, lipopolysaccharide, and glucagon-like peptides were measured by ELISA before (T0) and after (T1) antimicrobial administration and after administration of A muciniphila or vehicle (T2). RESULTS A muciniphila was detected in feces in 7 of 8 dogs after A muciniphila treatment at T2 (3/4 experiments) but not at T0 or T1. After metronidazole administration, mean change in plasma cytokeratin-18 concentration from T1 to T2 was significantly lower with vehicle than with A muciniphila treatment (−0.27 vs 2.4 ng/mL). Mean cytokeratin-18 concentration was lower at T1 than at T0 with amoxicillin-clavulanate. No other significant biomarker concentration changes were detected. Probiotic administration was not associated with changes in fecal scores. No adverse effects were attributed to A muciniphila treatment. CONCLUSIONS AND CLINICAL RELEVANCE Detection of A muciniphila in feces suggested successful gastrointestinal transit following oral supplementation in dogs. Plasma cytokeratin-18 alterations suggested an effect on gastrointestinal epithelium. Further study is needed to investigate effects in dogs with naturally occurring gastrointestinal disease.

OBJECTIVE To assess the in vitro effects of doxorubicin and tetrathiomolybdate (TM) on cells from a canine hemangiosarcoma cell line. SAMPLE Cultured cells from the canine hemangiosarcoma–derived cell line DEN-HSA. PROCEDURES Cells were treated with TM (0 to 1.5μM), doxorubicin (0 to 5μM), or both with or without 24 hours of pretreatment with ascorbic acid (750μM). Degree of cellular cytotoxicity was measured with a colorimetric assay. Long-term growth inhibition was assessed with a 10-day colony-formation assay. Induction of apoptosis was quantitated by fluorometric assessment of caspase-3 and −7 activation. Formation of reactive oxygen species (ROS) was also detected fluorometrically. RESULTS Exposure of cells to the combination of TM and doxorubicin resulted in a greater decrease in proliferation and clonogenic survival rates than exposure to each drug alone. This treatment combination increased ROS formation and apoptosis to a greater extent than did doxorubicin or TM alone. Ascorbic acid inhibited both TM-induced ROS formation and apoptosis. CONCLUSIONS AND CLINICAL RELEVANCE Results suggested that the enhancement in cytotoxic effects observed with DEN-HSA cell exposure to the combination of doxorubicin and TM was achieved through an increase in ROS production. These findings provide a rationale for a clinical trial of this treatment combination in dogs with hemangiosarcoma.

The objectives of the study were to: i) determine baseline microvascular perfusion indices (MPI) and assess their repeatability in healthy horses under general anesthesia, and ii) compare the MPIs of 3 microvascular beds (oral mucosa, colonic serosa, and rectal mucosa). Healthy adult horses were anesthetized and sidestream dark field microscopy was used to collect video loops of the oral mucosa, rectal mucosa, and colonic serosa under normotensive conditions without cardiovascular support drugs; videos were later analyzed to produce MPIs. Baseline MPI values were determined for each site, which included the total vessel density (TVD), perfused vessel density (PVD), portion perfused vessels (PPV), and microcirculatory flow index (MFI). Differences in MPIs between microvascular beds were not statistically significant. Repeatability of the measurements varied for each MPI. In particular, the site of sampling had a profound effect on the repeatability of the PPV measurements and should be considered in future studies.

OBJECTIVE To evaluate a fluorescence resonance energy transfer quantitative PCR (FRET-qPCR) assay for detection of gyrA mutations conferring fluoroquinolone resistance in canine urinary Escherichia coli isolates and canine urine specimens. SAMPLE 264 canine urinary E coli isolates and 283 clinical canine urine specimens. PROCEDURES The E coli isolates were used to validate the FRET-qPCR assay. Urine specimens were evaluated by bacterial culture and identification, isolate enrofloxacin susceptibility testing, and FRET-qPCR assay. Sensitivity and specificity of the FRET-qPCR assay for detection of gyrA mutations in urine specimens and in E coli isolated from urine specimens were computed, with results of enrofloxacin susceptibility testing used as the reference standard. RESULTS The validated FRET-qPCR assay discriminated between enrofloxacin-resistant and enrofloxacin-susceptible E coli isolates with an area under the receiver operating characteristic curve of 0.92. The assay accurately identified 25 of 40 urine specimens as containing enrofloxacin-resistant isolates (sensitivity, 62.5%) and 226 of 243 urine specimens as containing enrofloxacin-susceptible isolates (specificity, 93.0%). When the same assay was performed on E coli isolates recovered from these specimens, sensitivity (77.8%) and specificity (94.8%) increased. Moderate agreement was achieved between results of the FRET-qPCR assay and enrofloxacin susceptibility testing for E coli isolates recovered from urine specimens. CONCLUSIONS AND CLINICAL RELEVANCE The FRET-qPCR assay was able to rapidly distinguish between enrofloxacin-resistant and enrofloxacin-susceptible E coli in canine clinical urine specimens through detection of gyrA mutations. Therefore, the assay may be useful in clinical settings to screen such specimens for enrofloxacin-resistant E coli to avoid inappropriate use of enrofloxacin and contributing to antimicrobial resistance.

OBJECTIVE To evaluate the efficacy of each of 3 incremental doses of MK-467 for alleviation of dexmedetomidine-induced hemodynamic depression in isoflurane-anesthetized cats. ANIMALS 6 healthy adult domestic shorthair cats. PROCEDURES Each cat was anesthetized with isoflurane and received a target-controlled infusion of dexmedetomidine estimated to maintain the plasma dexmedetomidine concentration at 10 ng/mL throughout the experiment. Heart rate (HR) and direct arterial pressures were measured at baseline (isoflurane administration only), during dexmedetomidine infusion, and before and after IV administration of each of 3 serially increasing doses (15, 30, and 60 μg/kg) of MK-467. Cardiac index (CI) and systemic vascular resistance (SVR) were recorded at baseline, during dexmedetomidine infusion, and at the mean arterial pressure nadir after administration of the 30- and 60-μg/kg doses of MK-467. RESULTS Compared with baseline values, the dexmedetomidine infusion significantly decreased HR and increased arterial pressures. Each dose of MK-467 caused a significant decrease in arterial pressures and a significant, albeit clinically irrelevant, increase in HR (≤ 10%). Following administration of the 30- and 60-μg/kg doses of MK-467, all cats developed clinical hypotension (mean arterial pressure, < 60 mm Hg) even though CI and SVR returned to baseline values. CONCLUSIONS AND CLINICAL RELEVANCE Results indicated administration of small doses of MK-467 to isoflurane-anesthetized cats receiving dexmedetomidine restored CI and SVR, but caused a substantial decrease in arterial pressures and only a marginal increase in HR. Therefore, caution should be used when MK-467 is administered to alleviate dexmedetomidine-induced hemodynamic depression in isoflurane-anesthetized cats.

The myoelectrical activity of the ovine gallbladder has not been fully recognised. Five rams were fitted with six small intestinal and three gallbladder electrodes and a strain gauge force transducer was mounted near the gallbladder fundic electrode. In two series of successive experiments, the electromyographical and mechanical recordings were recorded over a period of 5-7 hours. The occurrence of the slow waves in the small bowel was regular, unlike those in the gallbladder. In the gallbladder infundibulum, the specific pattern, called the long spike burst pattern (LSBP), was observed. It comprised usually one or two parts of prolonged duration. The first part resembled the classical (short lasting) spike burst in the small bowel, and its amplitude was lower than that of the second part. The spike burst frequency of the second part was 2-3 times lower than that of the first part. During phase 1-like and phase 2a-like activities, the intensity of the gallbladder LSBP was reduced while enhanced after feeding. In fasted rams, the duration of a specific pattern, observed in the gallbladder infundibulum, was longer than in non-fasted animals and its amplitude was low. Similar events were recorded in the gallbladder corpus, but the specific pattern was shorter and irregular. In the gallbladder fundus, mostly irregular short spike bursts were recorded. It is concluded that in sheep, specific types of the long-lasting groups of spikes occur in the upper gallbladder areas exhibiting myoelectrical regional variability. The character of an LSBP depends on feeding conditions.

Recent years have seen a change in the relative prevalence of environmental and contagious intramammary pathogens, as well as a change in the relative number of total mixed ration (TMR)-based and pasture (PAS)-based dairies in South Africa. The objectives of the study were to determine and compare the prevalence of mastitis pathogens in TMR and PAS dairies in South Africa during 2008 and 2013; furthermore, the within-herd prevalence of Streptococcus uberis in Str. uberis-positive herds was determined and compared. The prevalence of each pathogen, as well as the within-herd prevalence of Str. uberis, were compared between the two years and the two management systems using bacterial culture results from routinely collected composite cow milk samples submitted to the Onderstepoort Milk Laboratory, Faculty of Veterinary Science, University of Pretoria. Coagulase-negative staphylococci had the highest prevalence in both TMR and PAS dairies for both 2008 (29.60% &#91;95.00% CI: 28.80% - 30.40%&#93; and 26.90% &#91;95.00% CI: 25.50% - 28.30%&#93;, respectively) and 2013 (20.20% &#91;95.00% CI: 19.30% - 21.10%&#93; and 22.70% &#91;95.00% CI: 22.20% - 23.10%&#93;, respectively), which decreased significantly from 2008 to 2013 in both TMR and PAS dairies (p < 0.001). Streptococcus uberis showed an increase in prevalence in both TMR (p = 0.002) and PAS dairies (p = 0.001) from 2008 (2.36% &#91;95.00% CI: 2.10% - 2.65%&#93; and 2.63% &#91;95.00% CI: 2.16% - 3.16%&#93;, respectively) to 2013 (3.10% &#91;95.00% CI: 2.72% - 3.51%&#93; and 3.64% &#91;95.00% CI: 3.45% - 3.83%&#93;, respectively). Staphylococcus aureus showed a significant decrease in both TMR (p = 0.011) and PAS (p < 0.001) dairies from 2008 (4.71% &#91;95.00% CI: 4.34% - 5.10%&#93; and 5.62% &#91;95.00% CI: 4.94% - 6.36%&#93;, respectively) to 2013 (3.95% &#91;95.00% CI: 3.52% - 4.40%&#93; and 1.71% &#91;95.00% CI: 1.58% - 1.84%&#93;, respectively). The median within-herd prevalence of Str. uberis for the combined dairy systems showed a significant increase from 2008 (1.72% &#91;IQR: 0.88% - 5.00%&#93;) to 2013 (3.10% &#91;IQR: 1.72% - 4.70%&#93;) (p < 0.001). Statistically significant differences were found in the prevalence of most of the major contagious and environmental mastitis pathogens between 2008 and 2013 and between TMR and PAS dairies. The within-herd prevalence of Str. uberis increased from 2008 to 2013, with the highest within-herd prevalence in PAS dairies in 2013.

Avian paramyxovirus type-1 (APMV-1) viruses of the lentogenic pathotypes are often isolated from wild aquatic birds and may mutate to high pathogenicity when they cross into poultry and cause debilitating Newcastle disease. This study characterised AMPV-1 isolated from fresh faecal droppings from wild aquatic birds roosting sites in Uganda. Fresh faecal samples from wild aquatic birds at several waterbodies in Uganda were collected and inoculated into 9-10-day-old embryonated chicken eggs. After isolation, the viruses were confirmed as APMV-1 by APMV-1-specific polymerase chain reaction (PCR). The cleavage site of the fusion protein gene for 24 representative isolates was sequenced and phylogenetically analysed and compared with representative isolates of the different APMV-1 genotypes in the GenBank database. In total, 711 samples were collected from different regions in the country from which 72 isolates were recovered, giving a prevalence of 10.1%. Sequence analysis of 24 isolates revealed that the isolates were all lentogenic, with the typical 111GGRQGR'L117 avirulent motif. Twenty-two isolates had similar amino acid sequences at the cleavage site, which were different from the LaSota vaccine strain by a silent nucleotide substitution T357C. Two isolates, NDV/waterfowl/Uganda/MU150/2011 and NDV/waterfowl/Uganda/MU186/2011, were different from the rest of the isolates in a single amino acid, with aspartate and alanine at positions 124 and 129, respectively. The results of this study revealed that Ugandan aquatic birds indeed harbour APMV-1 that clustered with class II genotype II strains and had limited genetic diversity.