Diagnosis of acute kidney injury (AKI) in horses is difficult at the subclinical stage, due to nonspecific clinical signs. The aim of this study was to evaluate the concentrations of selected serum and urinary biomarkers in healthy horses, horses at risk of AKI, and those with clinical AKI. Thirty healthy horses, 30 horses at risk of AKI and 11 horses with clinical AKI and azotaemia were included in the study. Serum and urinary neutrophil gelatinase-associated lipocalin (NGAL) and cystatin C were measured using commercially available enzyme immunoassay tests. The median and (in parentheses) first and third quartile concentrations of selected biomarkers in healthy horses, horses at risk of AKI and horses with AKI were respectively as follows: serum cystatin C – 0.25 (0.19–0.37), 0.23 (0.15–0.37) and 0.61 (0.37–1.13) mg/L; serum NGAL – 50.5 (38.8–58.8), 51.1 (40.4–66.9) and 98.1 (59.4–128.2) ng/mL; urinary NGAL – 20.7 (17.9–24.5), 32.3 (32.7–55.8) and 36.6 (26.8–89.9) ng/mL; and urinary cystatin C – 0.1 (0.07–0.13), 0.13 (0.1–0.2) and 0.34 (0.22–0.37) mg/L. There were significant differences in the concentration of all biomarkers between the healthy and AKI-affected horses. Horses with AKI all had biomarker concentrations higher than the healthy horses. None of the biomarkers made azotaemia recognisable in all affected horses. The obtained results indicate the need to create a serum and urinary biomarker panel to detect AKI.

OBJECTIVE To characterize physical examination, plasma biochemical, and ultrasonographic findings in aquarium-housed, managed semiwild, and wild southern stingrays (Hypanus americanus) with and without reproductive disease. ANIMALS Southern stingrays from aquarium (n = 48), lagoon (managed semiwild; 34), and wild (12) habitats. PROCEDURES Limited, opportunistic prosections were performed of presumed anatomically normal wild southern stingrays and compared with findings for aquarium-housed stingrays with reproductive disease. Ultrasonographic video data from both groups were used to assign a score (1 to 5) indicating increasing severity of ovarian and uterine reproductive disease. Plasma total 17β-estradiol, estrone, progesterone, and testosterone concentrations were measured with enzyme immunoassays validated for use in southern stingrays. RESULTS Ultrasonographic ovarian scores were significantly correlated with uterine scores. No reproductive disease was detected in semiwild or wild stingrays, but 65% (31/48) of aquarium-housed stingrays had developing or advanced reproductive disease (ie, ultrasonographic ovarian or uterine score of 4 or 5). Significant correlations were identified between ovarian and uterine disease status and plasma concentrations of all steroid hormones except testosterone. CONCLUSIONS AND CLINICAL RELEVANCE Findings suggested that ultrasonography and plasma hormone concentrations may be useful in the identification of reproductive disease and determination of disease severity in southern stingrays.

OBJECTIVE To measure serum homocysteine concentrations in dogs with myxomatous mitral valve disease (MMVD) and identify any association between this variable and stage of MMVD. ANIMALS 53 client-owned dogs with MMVD and 10 healthy control Beagles. PROCEDURES Dogs with MMVD were allocated to 3 groups in accordance with the staging system for chronic valvular heart disease in dogs and cats of the American College of Veterinary Internal Medicine. Blood samples were collected from all dogs, and serum homocysteine and cardiac troponin 1 concentrations were measured by enzyme immunoassay and chemiluminescence immunoassay, respectively. Analyte values were tested for associations with each other and with stage of MMVD. RESULTS A significant correlation was identified between serum homocysteine concentration and stage of MMVD. Mean ± SD concentrations were 6.72 ± 1.65 μmol/L for control dogs, 13.37 ± 4.16 μmol/L for dogs with stage B MMVD, 18.86 ± 6.73 μmol/L for dogs with stage C disease, and 28.26 ± 4.48 μmol/L for dogs with stage D disease. In addition, serum homocysteine concentration was correlated with serum cardiac troponin 1 (r = 0.34) and creatinine (r = 0.46) concentrations, systolic blood pressure (r = 0.57), and left atrium-to-aortic root ratio (r = 0.28), all of which were positively correlated with stage of MMVD. CONCLUSIONS AND CLINICAL RELEVANCE Serum homocysteine concentrations of dogs with MMVD were significantly higher than those of control dogs, and significant correlations were identified between these values and several risk factors for heart failure. Measurement of serum homocysteine concentration may be useful in the prediction of severity of disease in dogs with MMVD.

Objective-To validate the use of a human enzyme immunoassay (EIA) kit for measurement of plasma antidiuretic hormone (ADH) concentration in dogs and evaluate plasma ADH concentrations in dogs with congestive heart failure (CHF) attributable to acquired cardiac disease, compared with findings in healthy dogs. Animals-6 healthy dogs and 12 dogs with CHF as a result of chronic degenerative valve disease or dilated cardiomyopathy. Procedures-Plasma samples from the 6 healthy dogs were pooled and used to validate the EIA kit for measurement of plasma ADH concentration in dogs by assessing intra-assay precision, dilutional linearity, and spiking recovery. Following validation, plasma ADH concentrations were measured in the 6 healthy dogs and in the 12 dogs with CHF for comparison. Results-The EIA kit measured ADH concentrations in canine plasma samples with acceptable intra-assay precision, dilutional linearity, and spiking recovery. The intra-assay coefficient of variation was 11%. By use of this assay, the median plasma concentration of ADH in dogs with CHF was 6.15 pg/mL (SD, 3.2 pg/mL; range, 4.18 to 15.47 pg/mL), which was significantly higher than the median concentration in healthy dogs (3.67 pg/mL [SD, 0.93 pg/mL; range, 3.49 to 5.45 pg/mL]). Conclusions and Clinical Relevance-Plasma ADH concentrations in dogs can be measured with the tested EIA kit. Plasma ADH concentrations were higher in dogs with CHF induced by acquired cardiac disease than in healthy dogs. This observation provides a basis for future studies evaluating circulating ADH concentrations in dogs with developing heart failure.

Objective: To determine concentration-dependent effects of tiludronate on cartilage explants incubated with or without recombinant equine interleukin-1β (rEq IL-1). Sample: Articular cartilage explants from the femorotibial joints of 3 young adult horses. Procedures: Cartilage explants were incubated with 1 of 6 concentrations (0, 0.19, 1.9, 19, 190, or 1,900 mg/L) of tiludronate and with or without rEq IL-1 (0.01 ng/mL) for 96 hours. Prostaglandin E2 (PGE2) concentrations in culture medium and explant digests were analyzed via PGE2 enzyme immunoassay. Sulfated glycosaminoglycan (sGAG) concentrations in culture medium were quantified via 1,9-dimethylmethylene blue assay. Chondrocyte apoptosis in paraffin embedded explant sections was measured via terminal deoxynucleotidyl transferase-mediated dUTP nick end–labeling assay. Relative gene expression of matrix metalloproteinases (MMPs), interleukin (IL)-6, and IL-8 was determined via the comparative cycle threshold method. Results: rEq IL-1 increased PGE2 concentration, sGAG release from explants, chondrocyte apoptosis, and MMP gene expression. Lower tiludronate concentrations reduced rEq IL-1–induced sGAG release and chondrocyte apoptosis, whereas the higher tiludronate concentrations increased sGAG release and chondrocyte apoptosis. At the highest tiludronate concentration evaluated, IL-8 gene expression was increased independent of whether rEq IL-1 was present. Conclusions and Clinical Relevance: Tiludronate had biphasic concentration-dependent effects on cartilage explants that were independent of PGE2 secretion or MMP gene expression. Low tiludronate concentrations had some chondroprotective effects, whereas high tiludronate concentrations were detrimental to equine articular cartilage. Administration of tiludronate intra-articularly to horses may be detrimental, dependent on the dose used. In vivo studies are needed before intra-articular tiludronate administration to horses can be recommended.

The purpose of this study was to investigate the relationship between swine health status and the concentration of the serum acute phase proteins, haptoglobin (HP), and C-reactive protein (CRP). A total of 378 clinically healthy pigs from farms A and B, plus 20 pigs culled from farm A due to poor growth, were used in this experiment. Each pig was examined and blood samples were collected during slaughter. The HP concentration was measured by using an HP-hemoglobin binding assay. The CRP concentration was measured by using a CRP enzyme immunoassay. Gross and histopathological lesions were examined and recorded at slaughter. Representative samples were then collected in order to isolate pathogens. Swine enzootic pneumonia, found in 47.7% of the pigs, was the most common lesion. Other lesions included pleuropneumonia (32.7%), suppurative pneumonia (10.3%), fibrinous pericardititis (4.3%), Ascaris migration in the liver (33.9%), and intestinal serositis (3.0%). On farm A, the percentage of pigs with 1 or more lesions was 88.2%. For culled pigs from farm A, the mean serum concentrations of HP and CRP were 2.23 +/- 0.14 mg/mL and 252.93 +/- 11.62 μg/mL, which were significantly higher than concentrations in clinically normal pigs (1.42 +/- 0.02 mg/mL and 84.88 +/- 2.61 μg/mL, respectively, P < 0.01). Moreover, among clinically normal farm A pigs, the mean HP concentration in pigs with lesions (1.43 +/- 0.02 mg/mL) was significantly higher than in pigs without lesions (1.32 +/- 0.07 mg/mL) (P < 0.05). However, the mean serum CRP concentrations in these animals were not significantly different. On farm B, the percentage of pigs with one or more lesions was 50.0%. Interestingly, the mean serum HP concentration in clinically normal pigs with lesions was significantly lower in farm B pigs (1.23 +/- 0.07 mg/mL) than in the farm A pigs (1.43 +/- 0.02 mg/mL; P < 0.01). However, serum CRP concentrations in farm A and B pigs were not significantly different. Serum HP concentration, which is a better indicator of inflammatory reactions in pig herds than serum CRP concentration, provides an important marker for swine health status.

We generated monoclonal antibodies (MAB) against feline immunodeficiency virus (FIV) and characterized these MAB by single competition enzyme immunoassays (EIA), immunoblot analysis, and radioimmunoprecipitation. Four MAB identified 3 distinct epitopes of the FIV p24/26 gag major core protein. One MAB recognized the p16/17 gag protein none recognized envelope proteins. We developed an FIV p26 antigen capture EIA that proved more sensitive (0.5 ng of p26/ml), less expensive, and less time-consuming than reverse transcriptase assay. The same MAB were used to develop an antibody EIA specific for FIV p26. The MAB and capture assays reported should prove useful in FIV diagnosis and research.

An enzyme immunoassay (EIA) was developed for detection of dexamethasone in equine blood. Dexamethasone 21-hemisuccinate-bovine serum albumin was used for immunization of rabbits, and prednisolone 21-hemisuccinate-horseradish peroxidase was used as enzyme conjugate. The assay had sensitivity in the low-picogram range (detection limit, 0.3 pg/well, 50% inhibition of binding at 4.5 +/- 0.7 pg/well). Apart from cortisol, which was recognized by the antiserum at concentration > 8.5 ng/ml, the dexamethasone antiserum failed to interfere with endogenous steroids, but cross-reacted with triamcinolone, flumethasone, and betamethasone. Thus, the antiserum was used to perform simultaneous screening for these synthetic glucocorticoids and to confirm their identity by combining reverse-phase high-performance liquid chromatography (RP-HPLC) and EIA. The immunoreactivity obtained by direct serum measurements was characterized by means of 2 independent RP-HPLC systems. Serum extracts were submitted to RP-HPLC systems I and II, and the fractions were tested by EIA. Immunoreactive peaks were identified by comparing their retention time with that of the standard glucocorticoids used for calibration. Coinjection of an internal standard (methylprednisolone) in RP-HPLC system II yielded reproducible relative retention times. The effectiveness of the test system was evaluated, using blood from a horse treated with commonly used veterinary preparations of dexamethasone. Administration of the free alcohol of dexamethasone and of dexamethasone 21-trioxaundecanoate, both given IV, was detected, and the identity of each was confirmed for up to 48 hours. Intramuscular administration of dexamethasone 21-isonicotinate was continued for at least 14 days after injection of a therapeutic dose. The technique provided higher sensitivity and practicability than do analytic techniques currently available for glucocorticoid testing in horses and proved reliable in confirming the identity of dexamethasone, triamcinolone, flumethasone, and betamethasone in equine blood samples.

Objective-To determine the usefulness of retina samples for detection of disease-associated prion protein by use of a commercially available enzyme immunoassay (EIA) intended for rapid identification of sheep and cattle with transmissible spongiform encephalopathies (TSEs). Samples-Retina, brainstem at the level of the obex, and retropharyngeal lymph node samples obtained from 15 TSE-inoculated sheep (scrapie [n = 13] or transmissible mink encephalopathy passaged through a bovid [2]); retina and brainstem samples obtained from 11 TSE-inoculated cattle (transmissible mink encephalopathy passaged through a bovid [7] or classical BSE [4]); and negative control tissue samples obtained from 2 sheep and 2 cattle that were not inoculated with TSEs. Procedures-Tissue samples were homogenized and analyzed for detection of abnormally folded disease-associated prion protein with a commercially available EIA and 2 confirmatory assays (western blot analysis or immunohistochemical analysis). Results-Retina sample EIA results were in agreement with results of brainstem sample EIA or confirmatory assay results for negative control animals and TSE-inoculated animals with clinical signs of disease. However, TSE-inoculated animals with positive confirmatory assay results that did not have clinical signs of disease had negative retina sample EIA results. Retina sample EIA results were in agreement with brainstem sample immunohistochemical results for 4 TSE-inoculated sheep with negative retropharyngeal lymph node EIA results. Conclusions and Clinical Relevance-Results of this study suggested that retina samples may be useful for rapid EIA screening of animals with neurologic signs to detect TSEs.

A commercially available automated enzyme-multiplied immunoassay technique (EMIT) was used to determine serum caffeine concentration after oral and IV administrations of caffeine at dosage of 5 mg/ kg of body weight to 12 clinically normal dogs. Dogs were allotted to 2 groups of 6 dogs each; 1 group initially received caffeine orally and the other received caffeine IV. After 72 hours, caffeine administration was repeated in all dogs in the alternate manner. Serum samples were obtained at multiple intervals over 24 hours to determine distribution and elimination kinetics. Analysis of the drug concentration-time data indicated IV elimination half-life (t1/2) of 6.39 +/- 1.87 hours, volume of distribution at steady state of 685.3 +/- 132.2 ml/kg, total body clearance of 1.31 +/- 0.38 ml/min/kg, absorption t1/2 of 1.02 +/- 0.68 hour, oral elimination t1/2 of 6.53 +/ - 2.72 hours, lag time after oral administration of 0.0614 +/- 0.0661 hour, highest measured concentration of 5.29 +/- 1.17 micrograms/ml, time to peak concentration of 2.74 +/- 1.30 hours, and bioavailability of 99.4 +/- 19.4%. Data from 6 dogs best fit a 1-compartment open model and those from 6 other dogs best fit a 2-compartment open model. On the basis of data from the 6 dogs that best fit a 2-compartment model, t1/2 of distribution was 0.58 +/- 0.72 hour. Data for oral administration best fit a single absorption phase and a single elimination phase. The increased availability and simplicity of the EMIT offers an opportunity to study the application of caffeine elimination for clinical evaluation of dogs with liver disease. Data obtained from this study allow determination of t1/2 and clearance to be simplified by obtaining samples 4 and 8 hours after oral or IV administrations and establishes canine reference values for elimination kinetics of caffeine administered at dosage of 5 mg/kg and assayed by use of the EMIT.