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Comparative oncology is a developing research discipline that is being used to assist our understanding of human neoplastic diseases. Companion canines are a preferred animal oncology model due to spontaneous tumor development and similarity to human disease at the pathophysiological level. We use a paired RNA sequencing (RNA-Seq)/microarray analysis of a set of four normal canine lymph nodes and ten canine lymphoma fine needle aspirates to identify technical biases and variation between the technologies and convergence on biological disease pathways. Surrogate Variable Analysis (SVA) provides a formal multivariate analysis of the combined RNA-Seq/microarray data set. Applying SVA to the data allows us to decompose variation into contributions associated with transcript abundance, differences between the technology, and latent variation within each technology. A substantial and highly statistically significant component of the variation reflects transcript abundance, and RNA-Seq appeared more sensitive for detection of transcripts expressed at low levels. Latent random variation among RNA-Seq samples is also distinct in character from that impacting microarray samples. In particular, we observed variation between RNA-Seq samples that reflects transcript GC content. Platform-independent variable decomposition without a priori knowledge of the sources of variation using SVA represents a generalizable method for accomplishing cross-platform data analysis. We identified genes differentially expressed between normal lymph nodes of disease free dogs and a subset of the diseased dogs diagnosed with B-cell lymphoma using each technology. There is statistically significant overlap between the RNA-Seq and microarray sets of differentially expressed genes. Analysis of overlapping genes in the context of biological systems suggests elevated expression and activity of PI3K signaling in B-cell lymphoma biopsies compared with normal biopsies, consistent with literature describing successful use of drugs targeting this pathway in lymphomas.

Houston, T., Chay, S., Woods, W.E., Combs, G., Kamerling, S., Blake, J.W., Edmundson, A.G., Vessiney, R. & Tobin, T. Phenylbutazone and its metabolites in plasma and urine of thoroughbred horses: population distributions and effects of urinary pH. J. vet. Pharmacol. Therap. 8, 136–149. A survey of plasma and urinary concentrations of phenylbutazone and its metabolites in thoroughbred horses racing in Kentucky was carried out. Poat-race blood samples from more than 200 horses running at Latonia Racetrack and Keeneland in the Spring of 1983 were analysed. The modal plasma concentration of phenylbutazone was between 1 and 2µg/ml, the mean concentration was 3.5µg/ml and the range was up to 15µg/ml. Oxyphenbuta-zone had a modal plasma concentration between 1 and 2µg/ml, a mean concentration of 2.07µg/ml and a range of up to 13µg/ml. γOH-phenylbutazone had a modal plasma concentration of less than 1µg/ml, a mean level of 1.39µg/ml and a range of up to 7.32µg/ml. All plasma concentration frequency distributions were well fitted by log normal distributions. Urinary concentrations of phenylbutazone yielded modal concentrations of less than 1µg/ml, a mean urinary concentration of 2.9µg/ml, with a range of up to 30.5µg/ml. This population fitted a log-normal distribution. For oxyphen-butazone, the modal concentration was less than 3µg/ml, the mean concentration was 15.26µg/ml, with a range to 81.5µg/ml. The frequency distribution of these samples was apparently bimodal. For γOH-phenylbutazone, the modal concentration was less than 4µg/ml, the mean concentration 21.23µg/ml, with a range of up to 122µg/ml. The population frequency distribution for γOH-phenylbutazone was indeterminate. Analysis of the pH of these post-race urine samples showed a bimodal frequency distribution. The pH values observed ranged from 4.9 to 8.7, with peaks at about pH 5.25 and 7.25. This bimodal pattern of urinary pH values is consistent with observations made in England and Japan. Urinary pH influenced the concentrations of phenylbutazone, oxyphenbuta-zone and γOH-phenylbutazone found in the urine samples. The concentration of these metabolites found in alkaline urines were from 32 to 225 times greater than those found in acidic urines. Plasma concentrations of phenylbutazone and its metabolites, however, were unaffected by urinary pH. In interlaboratory experiments, horses running at Hollywood Park were dosed with phenylbutazone at about 2g/1000 lbs 24 and 48 h before racing, and a mean dose of 0.6g/1000 lbs at 72 h prior to racing. Post-race plasma samples from these horses showed phenylbutazone concentrations ranging from 0.44 to 9.97µg/ml, with a mean concentration of 4.09µg/ml. Plasma oxyphenbutazone concentrations in these horses varied from 0.8µg/ml to 11.3µg/ml, with a mean of 5.3µg/ml. Comparison of plasma concentrations of phenylbutazone and oxyphenbutazone in horses racing in Kentucky, with the results of dosing experiments in horses in training, suggests that most horses racing in Kentucky are being dosed with amounts of phenylbutazone broadly equivalent to, or less than, proposed ‘no-race-day medication rule’ dosing schedules. T. Tobin, Kentucky Equine Drug Research and Testing Programs, Department of Veterinary Science, University of Kentucky, Lexington, KY 40546-0076, U.S.A.

Phenylbutazone is an acidic, lipophilic, non-steroidal anti-inflammatory drug (NSAID). It is extensively metabolized in the horse. The metabolites so far identified, oxyphenbutazone, gamma-hydroxyoxyphenbutazone, account for some 25-30% of administered dose over 24 h. The plasma half-life of phenylbutazone and termination of its pharmacological action are determined primarily by its rate of hepatic metabolism. Phenylbutazone acts by inhibiting the cyclooxygenase enzyme system, which is responsible for synthesis of prostanoids such as PGE2. It appears to act on prostaglandin-H synthase and prostacyclin synthase, after conversion by prostaglandin-H synthase to reactive intermediates. It markedly reduces prostanoid-dependent swelling, edema, erythema, and hypersensitivity to pain in inflamed tissues. Its principal use in the horse is for treatment of soft tissue inflammation. Phenylbutazone is highly bound (greater than 98%) to plasma protein. After i.v. injection, blood levels decline with an elimination half-life of 3-10 h. The plasma kinetics of phenylbutazone may be dose dependent, with the plasma half-life increasing as the drug dosage level increases. Plasma residues of the drug at 24 h after a single i.v. dose of 2 g/450 kg average about 0.9 microgram/ml, but considerable variation occurs. If dosing is repeated, the plasma residue accumulates to give mean residual blood levels of approximately 4.5 microgram/ml on Day 5 after 4 days of dosing. Approximately similar blood levels are found after a combination of oral and i.v. dosing. Experiments on large numbers of horses in training have been undertaken to ascertain the population distributions of residual blood levels after such dosing schedules. Absorption of phenylbutazone from the gastrointestinal tract is influenced by the dose administered and the relationship of dosing to feeding. Access to hay can delay the time of peak plasma concentration to 18 h or longer. Under optimal conditions, the bioavailability of oral phenylbutazone is probably in the region of 70%. Paste preparations may be more slowly absorbed than other preparations and yield higher residual plasma levels at 24 h after dosing, but further controlled studies are required. Phenylbutazone is easily detected in the plasma and urine of horses but concentrations in saliva are low. It is quantitated for forensic purposes by HPLC. The variability of this method between laboratories is about +/- 25%. Increasing urinary pH increases the urinary concentration of phenylbutazone and its metabolites up to 200-fold.(ABSTRACT TRUNCATED AT 400 WORDS)

The effects of naloxone on the cardiovascular, hematologic and metabolic derangements associated with endotoxic and hemorrhagic shock were studied in unanesthetized horses. In the first of 3 experiments blood glucose and lactate levels, hematocrit, white, red and differential white cell counts, rectal temperature and clinical signs were obtained before and after endotoxin (10 micrograms/Kg) administration in 5 horses. In the second experiment, two groups of 3 horses received either intravenous naloxone (0.04 mg/Kg) or saline, 7 minutes prior to endotoxin. In a third experiment two groups of 4 horses received either saline or naloxone (0.20 mg/Kg) immediately following acute hemorrhage. In the second and third experiments, pulse, mean arterial and right ventricular pressures, and heart rate were also observed. Endotoxin and acute hemorrhage produced hypothermia, leukopenia, lymphopenia, neutropenia, elevations in hematocrit, blood glucose and blood lactate, and clinical signs of shock. Naloxone (0.040 mg/Kg IV) significantly lowered endotoxin-induced increases in right ventricular pressure and heart rate, and at a higher dose (0.20 mg/Kg) antagonized the decrease in pulse and heart rate, and tachycardia observed after acute hemorrhage. These results suggest endogenous opioids are involved in the pathogenesis of shock. Naloxone appeared to attenuate some of the cardiovascular responses associated with shock and thus may be of therapeutic value in shock management.