bluuebunny/crossref_metadata_2025_split huggingface dataset:
The pharmacokinetics, pharmacological responses and behavioral effects of acepromazine in the horse
Authors: BALLARD S. , SHULTS T. , KOWNACKI A. A. , BLAKE J. W. , TOBIN T. 
Published: April 2008

After intravenous (i.v.) injection, acepromazine was distributed widely in the horse (Vd= 6.6 litres/kg) and bound extensively (>99%) to plasma proteins. Plasma levels of the drug declined with an α phase half‐life of 4.2 min, while the β phase or elimination half‐life was 184.8 min. At a dosage level of 0.3 mg/kg acepromazine was detectable in the plasma for 8 h post dosing. The whole blood partitioning of acepromazine was 46% in the plasma phase and 54% in the erythrocyte phase.Penile prolapse was clearly evident at doses from 0.01 mg/kg to 0.4 mg/kg i.v., and the duration and extent of protrusion were dose related. Hematocrit levels were significantly lowered by administration of 0.002 mg/kg i.v. (about 1 mg to a 500 kg horse) and increasing dosages resulted in greater than 20% lowering of the hematocrit from control levels. Pretreatment of horses with acepromazine also reduced the variable interval (VI 60) responding rate in all horses tested.These data show that hematocrit changes are the most sensitive pharmacological responses to acepromazine, followed by changes in penile extension, respiratory rate, VI responding and locomotor responses. Acepromazine is difficult to detect in plasma at normal clinical doses. However, because of its large volume of distribution, its urinary elimination is likely prolonged, and further work on its elimination in equine urine is required.
Influence of dopamine on rumino‐reticular motility and rumination in sheep
Authors: BUÉNO L. , SORRAING J. M. , FIORAMONTI J. 
Published: April 2008

The effects of intracerebroventricular (i.c.v.) and intravenous (i.v.) administration of dopamine and its antagonists (domperidone and metoclopramide) on forestomach motility were investigated in four sheep fitted with Nichrome electrodes and strain gauges implanted on the reticulum and the caudo‐dorsal sac of the rumen.Infused by the i.c.v. route at a rate of 2 μg·kg‐1·min‐1, dopamine inhibited the phasic contractions of the reticulo‐rumen. A similar effect was obtained following i.v. administration of doses which were 10 times higher, but the effect was associated with an increased tone of the rumen wall. Prior i.v. administration of domperidone (0.5 μg·kg‐1) blocked these effects and a selective blockade of the dopamine‐induced inhibition of phasic contractions was obtained with higher dose of domperidone (2.5 μg·kg‐1) administered centrally.When dopamine was infused alone ventricularly or intravenously after metoclopramide (40 μg·kg‐1), it induced a transient (6–8 min) period of rumination, which could be blocked by a prior i.c.v. administration of tolazoline.It was concluded that dopamine acts on rumino‐reticular motility in sheep through specific dopamine receptors (i) centrally by inhibiting the frequency of reticular contraction and (ii) peripherally by increasing the muscular tone of the rumen, and its effects on rumination involved α2 adrenergic receptors located in the central nervous system.
Radioimmunoassay of the anabolic agent zeranol. II. Zeranol concentrations in urine of sheep and cattle implanted with zeranol (Ralgro)
Authors: DIXON S. N. , RUSSELL K. L. 
Published: April 2008

A radioimmunoassay for zeranol has been validated and used to measure the concentration of zeranol in the urine of sheep and cattle treated with zeranol (Ralgro). The assay uses an antibody raised against zeranol‐16‐carboxy‐propyl ether conjugated to human serum albumin. In sheep and cattle urine the limits of detection were approximately 2 ng/ml and 2.5 ng/ml, respectively.In two trials 13 sheep were implanted with 12 mg zeranol at the base of the ear. The mean maximum concentrations of zeranol observed in urine were 45 ng/ml (Trial I) on day 35 and 90 ng/ml (Trial II) on day 56, and had declined to 26 ng/ml 42 days after implantation (Trial I) and 11.7 ng/ml 70 days after implantation (Trial II). In four cattle implanted with 36 mg zeranol the concentrations of zeranol in urine reached a mean maximum concentration of 13.5 ng/ml 22 days after implantation and had declined to 2.9 ng/ml 69 days after implantation.
Comparison of pharmacokinetics of sodium and lysine cephalexin in calves
Authors: CARLI S. , PERRETTA G. , BRUSA T. , INVERNIZZI A. , FAUSTINI R. 
Published: April 2008

The pharmacokinetics of sodium and lysine cephalexins were investigated after intravenous and intramuscular administration of a single dose rate of 30 mg.kg‐1 body weight in calves.The data for the two salts administered intravenously were pooled, the resulting pharmacokinetic disposition of cephalexin indicating a distribution half‐time (t1/2α) and an elimination half‐time (t1/2β) of 9.78 and 62.0 min, respectively.Following intramuscular administration some pharmacokinetic differences were recorded between the cephalexin preparations: lysine cephalexin was more rapidly eliminated (t1/2kel= 55.2 min) than sodium cephalexin (t1/2kel= 89.8 min), although the peak blood level was higher and attained after a longer time with lysine cephalexin.
Distribution of oxytetracycline into ocular tissues and tears of calves
Authors: GEORGE LISLE W. , SMITH J. A. , KASWAN RENEE 
Published: April 2008

George, L., Smith, J. & Kaswan, R. Distribution of oxytetracycline into ocular tissues and tears of calves. J. vet. Pharmacol. Therap. 8, 47–54.A long‐acting oxytetracycline formulation was administered (20 mg/kg of body weight) intramuscularly to calves, and the concentrations of the drug in serum, ocular tissues and tears were measured. The drug was distributed selectively to the epithelium of the conjunctiva and to the lacrimal gland ductules, and reached concentrations in each tissue that exceeded those in serum. The drug did not penetrate into the aqueous humour, and produced mean peak lacrimal fluid concentrations <1 μg/ml after i.m. administration. When given subconjunctivally, however, concentrations > 2.0 μg/ml were observed in tears for 72 h. Severe local reactions occurred in all calves that were given the drug subconjunctivally. Lisle W. George, Department of Medicine, School of Veterinary Medicine, University of California, Davis, CA 95616, U.S.A.
Apramycin: minimal inhibitory concentrations for avian Escherichia coli and serum levels after intramuscular injection in turkeys
Authors: FREIDLIN P. J. , BOCK R. , BERNATH A. , HOEXTER S. , ZIV G. , FROMER A. , PERLSTEIN Z. , TOMER S. , SAMBERG Y. 
Published: April 2008

Freidlin, P.J., Bock, R., Bernath, A., Hoexter, S., Ziv, G., Fromer, A., Perlstein, Z., Tomer, S. & Samberg, Y. Apramycin: minimal inhibitory concentrations for avian Esclierichia coli and serum levels after intramuscular injection in turkeys. J. vet. Pharmacol. Therap. 8, 105–109.The minimal inhibitory concentrations (MIC) of apramycin, a unique amino‐cyclitol antibiotic, for 100 Escherichia coli isolates recovered from clinical cases of avian colibacillosis were determined using the agar dilution method. All isolates were inhibited at apramycin concentration of 8.0 μg/ml; 90 and 50% of the isolates were inhibited at 6.6 and 3.4 μg/ml, respectively.A commercial injectable product containing 200 mg apramycin/ml was administered intramuscularly (i.m.) to groups of 6‐and 12‐week‐old turkeys at 10, 15 and 20 mg/kg. Apramycin was quickly absorbed from the i.m. injection site. Mean peak serum drug concentrations were reached 1 h after treatment and were 19.5, 27.5 and 36.0 μg/ml, respectively. The serum elimination half‐life (1/2) of the drug ranged between 1.75 h for the 10 mg/kg dose and 2.5 h for the 20 mg/kg dose. Very low concentrations of the drug were found 24 h after treatment. Duration of serum apramycin concentrations in relation to the MIC, dose, and age of birds was determined. Dr G. Ziv, Ministry of Agriculture, Kimron Veterinary Institute, P.O. Box 12, Bet‐Dagan, Israel.
Pharmacokinetics of probenecid in sheep
Authors: GUERRINI V. H. , FILIPPICH L. J. , ENGLISH P. B. , SCHNEIDER JENNY , CAO G. R. , BOURNE D. W. A. 
Published: April 2008

Guerrini, V.H., Filippich, L.J., English, P.B., Schneider, J., Cao, G.R. & Bourne, D.W.A. Pharmacokinetics of probenecid in sheep. J. vet. Pharmacol. Therap. 8, 128–135.Six Merino ewes were given 1g (27g/kg) probenecid by the intravenous (i.v.), intramuscular (i.m.) and subcutaneous (s.c.) routes. After i.v. injection, the biological half‐life was 1.55 h and apparent volume of distribution at the steady state (Vdss) 0.18l/kg. Body clearance (ClB)and renal clearance (ClR) were 0.12l/h/kg and 0.03l/h/kg, respectively. Approximately 28% of unchanged probenecid was excreted in urine. Plasma probenecid concentrations after i.v., i.m. and s.c. injections were 133, 37, and 31 μg/ml, respectively, at 15 min; 76, 36, and 34μg/ml at 1 h; and 43, 23 and 34μg/ml at 2 h. The average bioavailability of probenecid given by i.m. and s.c. injection was 46% and 34%, respectively. However, after 2 h, probenecid plasma concentrations remained higher when it was given subcutaneously than when it was given intramuscularly.Urine output was correlated positively (P < 0.05) with kel and ClB. Urine pH increased significantly (P < 0.01) for the first 2 h, and then steadily declined over the subsequent 6 h. The results suggested that probenecid in sheep was rapidly eliminated because it was rapidly excreted in the normal but alkaline urine. Subcutaneous administration of probenecid in animals may be a useful alternative to oral or i.v. administration. Dr V. H. Guerrini, Department of Pharmacy, University of Queensland, St Lucia, Queensland 4067, Australia.
Effects of phenylbutazone and oxyphenbutazone on basic drug detection in high performance thin layer chromatographic systems*,†
Authors: WOODS W. E. , CHAY S. , HOUSTON T. , BLAKE J. W. , TOBIN T. 
Published: April 2008

Woods, W.E., Chay, S., Houston, T., Blake, S.W. & Tobin, T. Effects of phenylbutazone and oxyphenbutazone on basic drug detection in high performance thin layer chromatographic systems. J. vet. Pharmacol. Therap. 8, 181–189.Interference or ‘masking’ in thin layer chromatography occurs when the presence of one drug on a thin layer plate physically obscures or interferes with the detection of another drug. We investigated the ability of phenylbutazone and oxyphenbutazone to mask or interfere with the detection by high performance thin layer chromatography (HPTLC) of basic drugs used illegally in horse racing. Of fifty‐five basic drugs called ‘positive’ since 1981 by laboratories affiliated with the Association of Official Racing Chemists (AORC), forty did not comigrate with phenylbutazone or oxyphenbutazone and could not, therefore, be masked. When 75μg/ml of oxyphenbutazone was spiked into urine samples, subjected to an extraction procedure for basic drugs, and then run in our routine HPTLC systems, no ‘spots’ due to oxyphenbutazone appeared. ‘Masking’ by oxyphenbutazone, therefore, did not and could not occur in our test systems. When phenylbutazone at a concentration of 30μg/ml was spiked into urine samples and run in the routine HPTLC system, phenylbutazone spots were visible under ultraviolet light and after certain specific oversprays were used to visualize basic drugs. These spots, however, did not interfere with routine thin layer testing for basic drugs. It was concluded that phenylbutazone and oxyphenbutazone had no significant ability to interfere with detection of the parent forms of these basic drugs under the conditions described in these experiments. T. Tobin, Kentucky Equine Drug Research and Testing Programs, Department of Veterinary Science, University of Kentucky, Lexington, KY 40546‐0076, U.S.A.
Low‐dose ethanol in the treatment of ethylene glycol poisoning
Authors: TARR BRYAN D. , WINTERS LORA J. , MOORE MICHAEL P. , COWELL RICK L. , HAYTON WILLIAM L. 
Published: April 2008

Tarr, B.D., Winters, L.J., Moore, M.P., Cowell, R.L. & Hayton, W.L. Low‐dose ethanol in the treatment of ethylene glycol poisoning. J. vet. Pharmacol. Therap. 8, 254–262.pharmacokinetic study was conducted to determine the effectiveness of lower doses of ethanol in the treatment of ethylene glycol (EG) poisoning. Four dogs were maintained at serum ethanol concentrations of 0, 35 and 140 mg/dl prior to EG (i.v., 2 ml/kg) administration. The serum EG concentration‐time data showed that the 35 mg/dl ethanol level provided as effective an inhibition of EG metabolism as did the 140 mg/dl level. The average urinary excretion rate of oxalic acid post EG administration was reduced to control levels by ethanol. The 35 mg/dl serum ethanol level reduced the total body clearance of EG from 93.9 to 50.0 ml/h/kg and increased the effective half‐life from 5.78 to 11.4 h.Clinical‐testing was accomplished by giving the dogs 12 ml EG/kg body weight orally. One hour later, the dogs were either not treated or treated with a sodium bicarbonate‐ethanol solution to obtain a serum ethanol concentration of 50 mg/dl. The clinical test performed in the ethanol‐treated dogs showed little change from normal limits. Urine calcium oxalate crystals were seldom found. The dogs given EG (12 ml/kg) but not treated with ethanol were in a coma at 13 h and showed severe metabolic acidosis, dehydration, mild hepatocellular disease and acute renal damage. Urine calcium oxalate crystals were found in high numbers. The rapid death associated with EG poisoning appeared to be due to metabolic acidosis in combination with dehydration. Bryan D. Tarr, College of Pharmacy, Washington Slate University, Pullman, WA 99164, U.S.A.
Intramuscular treatment of subclinical staphylococcal mastitis in lactating cows with penicillin G, methicillin and their esters
Authors: ZIV G. , STORPER M. 
Published: April 2008

Ziv, G. &: Storper, M. Intramuscular treatment of subclinical staphylococcal mastitis in lactating cows with penicillin G, methicillin and their esters. J. vet. Pharmacol. Therap. 8, 276–283.The relationship between antibiotic milk concentrations and bacteriological efficacy was investigated in groups of lactating cows with subclinical mastitis due to either penicillin G‐sensitive or penicillin G‐resistant Staphylococcus aureus. Treatments consisted of the intramuscular injection of procaine penicillin G, or its weak base ester penethamate hydriodide, and sodium methicillin, or its weak base ester tamethicillin. Antibiotics were administered once daily for 2 or 4 days at accepted dosages.After four daily, treatments with procaine penicillin G and penethamate hydriodide, infections were eliminated from 56.5% and 68.8%, respectively, of quarters infected with penicillin G‐sensitive staphylococci, and from 14.3% and 7.7%, respectively, of quarters infected with penicillin G‐resistant staphylococci. After four daily treatments with sodium methicillin and tamethicillin, infections were eliminated from 32.4% and 48.6%, respectively, of quarters infected with penicillin G‐resistant staphylococci. The better efficacy of penethamate hydriodide and tamethicillin was considered to be linked to the higher milk drug concentrations obtained with these drugs as opposed to the lower concentrations measured in the milk after treatment with the parent drugs. Cure rates were generally higher after treatment for 4 days than after the 2‐day course of therapy. Treatment efficacy decreased progressively with increasing age of the cows.Intramuscular treatment of subclinical staphylococcal mastitis in lactating cows can serve as a useful model for screening existing and new antibacterial agents and drug products intended for the parenteral treatment of clinical staphylococcal mastitis. Dr G. Ziv, Ministry of Agriculture, Kimron Veterinary Institute, Bet‐Dagan, Israel.
Cardiovascular and respiratory effects of acetylpromazine and xylazine on halothaneanesthetized horses
Authors: STEFFEY E. P. , KELLY A. B. , FARVER T. B. , WOLINER M. J. 
Published: April 2008

Steffey, E.P., Kelly, A.B., Farver, T.B. & Woliner, M.J. Cardiovascular and respiratory effects of acetylpromazine and xylazine on halothane‐anesthetized horses. J. vet. Pharmacol. Therap. 8, 290–302.Circulatory and respiratory effects of intravenously administered acetylpromazine (0.033 and 0.067 mg/kg) and xylazine (0.5 and 1.0 mg/kg) were studied in drug cross‐over fashion in eight laterally recumbent horses anesthetized only with halothane (1.06%, end‐tidal) in O2. Both doses of acetylpromazine caused a significant and sustained elevation in cardiac output via a rise in stroke volume. Xylazine produced an initial significant fall in cardiac output followed by a return to control levels. Halothane anesthesia did not prevent xylazine‐related atrioventricular conduction block. All treatments caused a similar significant fall in arterial blood pressure (acetylpromazine, total peripheral resistance‐related; xylazine, cardiac output‐related). PaCO2 significantly increased after all treatments. PaCC2 decreased significantly only following xylazine treatment. One horse (not included in the tabulation) developed ventricular fibrillation and died 15 min after receiving its first injection (0.5 mg/kg) of xylazine. Dr E. P. Steffey, Department of Surgery, School of Veterinary Medicine, University of California, Davis, CA 95616, U.S.A.
Radioimmunoassay of the anabolic agent zeranol. IV. The determination of zeranol concentrations in the edible tissues of cattle implanted with zeranol (Ralgro)
Authors: DIXON S. N. , RUSSELL K. L. 
Published: April 2008

Rapid solvent extraction combined with a radioimmunoassay using a nionoclonal antibody raised against a derivative of zeranol has been used to measure the residues of the anabolic agent zeranol in the edible tissues (muscle, liver, kidney and fat) of cattle treated with Ralgro.Calibration curves, both with and without, tissue extracts exhibit good parallelism. Regression analysis for the extraction of‐ zeranol from tissues dosed with standard amounts of zeranol have correlation coefficients of 0.979, 0.99 1, 0.986 and 0.985 for muscle, liver, kidney and fat, respectively.The limits of decision defined as the mean value + 3 SD for the concentrations apparently observed (noise) in tissues from animals not treated with Kalgro were 278, 121, 373 and 110 ng/kg for muscle, fat, liver and kidney, respectively. In the tissues of 4 cows implanted with Ralgro (36 mg), and sampled 70 clays after iniplanting, the highest concentration of zeranol in each tissue was 232 ng/kg (muscle), 391 ng/kg (liver), 287 nglkg (kidney) and 293 nglkg (fat), and residues were detected in all samples of fat (4), 3 kidney samples and I liver sample.
Pharmacokinetics of trimethoprim/sulfadiazine in neonatal calves: influence of synovitis
Authors: SHOAF S. E. , SCHWARK W. S. , GUARD C. L. , SCHWARTSMAN R. V. 
Published: April 2008

Shoaf, S.E., Schwark, W.S., Guard, C.L. & Schwartsman, R.V. Pharmacokinetics of trimethoprim/sulfadiazine in neonatal calves: influence of synovitis. J. vet. Pharmacol. Therap. 9, 446–454, 1986.The effect of synovitis on the distribution of antibacterial drugs into the joint space was studied in 1‐week‐old calves. Sodium urate crystals were used to induce inflammation in the tibio‐tarsal joint of calves and the antibacterial drug combination, trimethoprim/sulfadiazine (Tribrissen®), 30 mg/kg, was administered intravenously 3 h after synovitis was induced. The degree of synovitis was monitored by serial WBC counts in synovial fluid. Trimethoprim (TMP) and sulfadiazine (SDZ) concentrations in serum and synovial fluid were measured and pharmacokinetic parameters were calculated. The results indicated that inflammation had no effect upon the concentrations of TMP/SDZ that reach the joint and that synovial fluid and blood are both representative of the central compartment as shown by the non‐significant differences in selected pharmacokinetic parameters for TMP and SDZ in these two body fluids. The distribution and elimination of TMP and SDZ in serum were described by a two‐compartment model.
Pharmacological modulation of postprandial colonic motor activity in the pony
Authors: ROGER T. , RUCKEBUSCH Y. 
Published: April 2008

Roger, T. & Ruckebusch, Y. Pharmacological modulation of postprandial colonic motor activity in the pony. J. vet. Pharmacol. Therap. 10, 273–282.The contractile activity of the equine large intestine exhibited a biphasic response to feeding: enhancement of migrating complexes passing along the colon and an increase of 50% in cyclic variations in smooth muscle at intervals of 20 min on the left ventral colon for a period of 5 to 7 h postfeeding. The cholinergic agonist, bethanechol (50 μg/kg subcutaneously), induced both the migrating complexes and the cyclic variations at intervals of 10–15 min. In contrast, the intra‐arterial infusion of PGF2a (3 μg/kg/min) increased the contractile activity during infusion, but without inducing distinct patterns of activity. Atropine but not indomethacin or flunixin pre‐treatment prevented the effects of postprandial, cholinergic and PGF2a stimulation of colonic motility, suggesting that the gastrocolonic reflex involved mainly cholinergic stimulation of the caecum and replicated colon, including the prostaglandin F2a excitatory effects.
A pharmacokinetic study of phenobarbital in mature horses after oral dosing
Authors: RAVIS W. R. , DURAN S. H. , PEDERSOLI W. M. , SCHUMACHER J. 
Published: April 2008

Ravis, W.R., Duran, S.H., Pedersoli, W.M. & Schumacher, J. A pharmacokinetic study of phenobarbital in mature horses after oral dosing. J. vet. Pharmacol. Therap.10, 283–289.The pharmacokinetics of phenobarbital were determined in six mature horses after a single oral dose. Horses were administered a 5.5 mg/kg of body weight oral dose of phenobarbital tablets. Based on the combined evaluation of i.v. and oral results, phenobarbital displayed two‐compartment pharmacokinetics in the horse with a terminal half‐life of 19.0 ± 4.4 (mean ± SD) h. This half‐life is considerably shorter than those reported for dogs and humans. The steady‐state volume of distribution (Vdss/F) and the total body clearance (Cl1/F) of phenobarbital were 0.753 ± 0.115 1/kg and 27.9 ± 9.2 ml/h/kg, respectively. The average extent of oral absorption was 101% with a range of 76 to 124% among the six horses. Examination of the absorption kinetics demonstrated a biphasic absorption process in four horses with a rapid absorption followed by a slower absorption phase. The mean residence time (MRT) was 36.9 ± 4.1 h and the mean residence time for oral absorption (MRTabs) was 11.3 h. Based on the results of the present study, an oral dosing regimen of 11 mg/kg of body weight every 24 h can be recommended.