Pharmacology in horses involves the study and application of drugs and medications to diagnose, treat, and prevent diseases and conditions in equine species. This field encompasses the understanding of pharmacokinetics and pharmacodynamics specific to horses, including how drugs are absorbed, distributed, metabolized, and excreted by the equine body. Commonly studied pharmacological agents in horses include non-steroidal anti-inflammatory drugs (NSAIDs), antibiotics, sedatives, and anthelmintics. Research in equine pharmacology focuses on determining appropriate dosages, understanding drug interactions, and minimizing adverse effects. This page compiles peer-reviewed research studies and scholarly articles that investigate the efficacy, safety, and regulatory aspects of pharmacological interventions in equine veterinary practice.
Boscan P, Steffey EP, Farver TB, Mama KR, Huang NJ, Harris SB.To compare anesthesia-related events associated with IV administration of 2 novel micellar microemulsion preparations (1% and 5%) and a commercially available formulation (1%) of propofol in horses. Animals-9 healthy horses. Methods: On 3 occasions, each horse was anesthetized with 1 of the 3 propofol formulations (1% or 5% microemulsion or 1% commercial preparation). All horses received xylazine (1 mg/kg, IV), and anesthesia was induced with propofol (2 mg/kg, IV). Induction and recovery events were quantitatively and qualitatively assessed. Venous blood samples were obtained before and at in...
Danek J.Four clinically normal stallions were infused intravenously with endotoxin (LPS) from Escherichia coli 055:B5 at a dose of 0.3 microg/kg b.w. and four stallions were treated with flunixin meglumine (FM) as a single intravenous injection at a dose of 1.1 mg/kg b.w., 5 min after the infusion of LPS. In response to endotoxin infusion, stallions' reaction was fever (increased rectal and scrotal skin temperature), increased heart rate (HR) and leucopenia. Administration of endotoxin also influenced the level of testosterone (decrease at 3-24 h and increase at 48-72 h after LPS administration) in th...
Franck T, Kohnen S, Deby-Dupont G, Grulke S, Deby C, Serteyn D.An original method called SIEFED (specific immunological extraction followed by enzymatic detection) was developed for the specific detection of the activity of equine myeloperoxidase (MPO). The method consists of the extraction of MPO from aqueous solutions by immobilized anti-MPO antibodies followed by washing (to eliminate proteins and interfering molecules) and measurement of MPO activity using a detection system containing a fluorogenic substrate, hydrogen peroxide, and nitrite as reaction enhancer. The SIEFED technique was applied to study active MPO in horse biological fluids and the ef...
Marttinen PH, Raulo SM, Suominen MM, Tulamo RM.The objective here was to evaluate the acute effects of induced arthritis on synovial fluid (SF) levels of matrix metalloproteinases (MMP) -2, -8 and -9 in horses. To evaluate MMP-2 and -9 activities and the effect of non-steroidal anti-inflammatory drug (NSAID) bufexamac during remission from acute arthritis. Aseptic arthritis was induced in 24 Standardbred horses using 20 mg of amphotericin B as a single intra-articular (IA) injection in the right intercarpal joint. After 1 week and 2 weeks, horses were treated intra-articularly with 10, 20, or 40 mg of bufexamac suspension or with sterile s...
Segura D, Monreal L, Pérez-Pujol S, Alonso A, Díaz-Ricart M, Brugués R, Ordinas A, Escolar G.The aim of this study was to investigate whether etamsylate produces equine platelet activation. In vitro and in vivo studies were designed in which seven and eight adult healthy horses were included, respectively. In the in vitro study, citrated blood was incubated with different concentrations of etamsylate, and P-selectin expression and annexin V binding were determined by flow cytometry. In the in vivo study, blood was collected before and 1 and 2h after IV administration of etamsylate, and P-selectin expression was evaluated. In the in vitro study, a significant increase in P-selectin exp...
Gehlen H, Groner U, Rohn K, Stadler P.In 18 horses, the pulmonary artery wedge pressure and the heart rate were measured during pharmacological stress load. 12 horses were healthy (4 trained, 8 untrained) and 6 horses had a heart disease (3 trained, 3 untrained). Pharmacological stress induction was carried out with the sympathomimetic drug dobutamine at a dosage rate of 7.5 microg/kg/min over 10 minutes of infusion. At the fourth minute, the parasympatholytic drug atropine was administered (5 microg/kg bw), and the heart rate and the pulmonary artery wedge pressure were continuously measured over 26 minutes. During sole dobutamin...
The Journal of parasitologyAugust 4, 2006
Volume 92, Issue 3 637-643 doi: 10.1645/0022-3395(2006)92[637:PAOPRC]2.0.CO;2
Furr M, McKenzie H, Saville WJ, Dubey JP, Reed SM, Davis W.The ability of ponazuril to prevent or limit clinical signs of equine protozoal myeloencephalitis (EPM) after infection with Sarcocystis neurona was evaluated. Eighteen horses were assigned to 1 of 3 groups: no treatment, 2.5 mg/kg ponazuril, or 5.0 mg/kg ponazuril. Horses were administered ponazuril, once per day, beginning 7 days before infection (study day 0) and continuing for 28 days postinfection. On day 0, horses were stressed by transport and challenged with 1 million S. neurona sporocysts per horse. Sequential neurologic examinations were performed, and serum and cerebrospinal fluid w...
Frye MA.Equine urinary tract infection (UTI) most commonly occurs as a sequela to structural or functional inhibition of normal urine flow. Although it is an infrequent diagnosis in equids, the incidence of UTI in human beings is high and has inspired great investigative effort. The resultant findings with potentially broad application as well as current equine studies are reviewed here. Recent developments in the understanding of host-agent interactions and renal defense mechanisms, emerging antimicrobial resistance, and novel therapeutic alternatives to prophylactic antibiotic use are emphasized.
Southwood LL.Although the use of antimicrobials has had an insurmountable impact on preventing patient morbidity and mortality, problems with antimicrobial resistance and antimicrobial-induced diarrhea are becoming more apparent in human and veterinary medicine. The mortality associated with nosocomial infection with antimicrobial-resistant bacteria in human patients is alarming. Similarly, in veterinary medicine, the morbidity and high cost of treatment of patients with postoperative infection, for example, are concerns. Specifically in equine medicine, the high morbidity and mortality associated with ant...
Dirikolu L, McFadden ET, Ely KJ, ElkHoly H, Lehner AF, Thompson K.Clonidine is classified as a class 3 performance-enhancing agent by the Association of Racing Commissioners International and thus has the potential to influence the outcome of a race. In this study, the authors developed and validated a sensitive gas chromatograph and mass spectrometer method to determine the pharmacokinetic parameters of clonidine in equine plasma samples after IV administration of a single dose (0.025 mg/kg) of clonidine in horses. At this dose, clonidine produced rapid and profound sedation, which cold be quickly reversed with yohimbine. Clonidine was able to produce an an...
Stokes AM, Venugopal CS, Hosgood G, Eades SC, Moore RM.The goals of this study were to determine the concentration-response (C-R) relationship of endothelin-1 (ET-1), compare 2 ET-receptor antagonists and determine the antagonist concentrations that block the vasomotor effects of ET-1, and compare the effectiveness of ET-1 and previously studied vasoconstrictors in equine palmar digital arterial and venous rings in vitro. Vessel rings from 8 nonlaminitic horses were placed in Tyrode's solution, 1 side fixed to the floor of an organ bath and the other side fixed to a force-displacement transducer. Two separate studies were conducted: (I) incubation...
Brandon CI, Vandenplas M, Dookwah H, Linden J, Murray TF.The aim of the current study was to clone the equine adenosine A(2A) receptor gene and to establish a heterologous expression system to ascertain its pharmacologic profile via radioligand binding and functional assays. An eA(2A)-R expression construct was generated by ligation of the eA(2A) cDNA into the pcDNA3.1 expression vector, and stably transfected into human embryonic kidney cells (HEK). Binding assays identified those clones expressing the eA(2A)-R, and equilibrium saturation isotherm experiments were utilized to determine dissociation constants (K(D)), and receptor densities (B(max)) ...
Brandon CI, Vandenplas M, Dookwah H, Murray TF.The aim of this study was to establish a heterologous expression system for the equine adenosine A(3) receptor (eA(3)-R) in an effort to ascertain its pharmacologic profile. Initially, radioligand binding assays identified clones expressing the eA(3)-R in human embryonic kidney cells (HEK) based on the specific binding of [(125)I]AB-MECA. Subsequently, adenylate cyclase assays were utilized to demonstrate functional coupling of the eA(3)-R to the G-protein/adenylate cyclase system. Equilibrium competition binding assays were then performed using selective and non-selective A(3) agonists and an...
Popot MA, Donval A, Bonnaire Y, Huau J.Feces are a possible medium to be used for horse doping control. Efficient methods for detecting drugs in feces collected from various animals are routinely applied in institutes of food safety in Belgium. We have already tested whether they are applicable to horse feces. In this report, accelerated solvent extraction (ASE), an efficient method for extracting compounds from solid material, has been tested. ASE has been used to replace the diethyl ether liquid-liquid extraction step present in the method initially set up. This technique has been optimized for detecting several non-steroidal ant...
Nogueira SA, Torres SM, Malone ED, Diaz SF, Jessen C, Gilbert S.Imiquimod is an immune response modifier with potent antiviral and antitumour activity. The objective of this pilot study was to evaluate the efficacy of an imiquimod 5% cream (Aldaratrade mark: 3M, Saint Paul, MN, USA) as a topical treatment for equine sarcoids. Fifteen horses with a total of 19 tumours were enrolled, including mixed (7), fibroblastic (5), flat (3), verrucous (2), and nodular (2) types. Baseline data included history, physical examination, tumour location, measurement and digital photography. Imiquimod was applied by the owners three times a week until complete resolution of ...
Raulo SM, Sorsa T, Maisi P.To evaluate inhibitory effects of synthetic matrix metalloproteinase (MMP) inhibitors in vitro on gelatinolytic and collagenolytic activities in tracheal epithelial lining fluid (TELF) of horses with recurrent airway obstruction (RAO). Methods: 10 horses with RAO and 5 healthy control horses. Methods: Substrate-based functional assays, collagen I and gelatin degradation, were used to measure endogenous collagenolytic and gelatinolytic activities in TELF. In vitro inhibition of MMP activity in TELF with 2 chemically modified tetracyclines (CMTs; CMT-3 and CMT-8) and 2 bisphosphonates (BPs; zole...
Eades SC, Stokes AM, Moore RM.To evaluate changes in digital vascular function in horses with carbohydrate overload (CHO)-induced laminitis and determine the effects of an endothelin (ET) receptor antagonist and nitroglycerin on laminitis-associated vascular dysfunction. Methods: 20 adult horses without abnormalities of the digit. Methods: Hemodynamic variables were recorded before (baseline) and hourly after all horses were administered a CHO ration via nasogastric tube. In 4 groups of 5 horses each, saline (0.9% NaCl) solution or ET receptor antagonist (10(5)M in digital blood) was administered into the digital arterial ...
Baird JD, Arroyo LG, Vengust M, McGurrin MK, Rodriguez-Palacios A, Kenney DG, Aravagiri M, Maylin GA.4 racehorses were examined because of markedly abnormal behavior following administration of fluphenazine decanoate. Results: Clinical signs included restlessness, agitation, profuse sweating, hypermetria, aimless circling, intense pawing and striking with the thoracic limbs, and rhythmic swinging of the head and neck alternating with episodes of severe stupor. Fluphenazine was detected in serum or plasma from all 4 horses. The dose of fluphenazine decanoate administered to 3 of the 4 horses was within the range (25 to 50 mg) routinely administered to adult humans. Results: In 2 horses, there ...
Koenig J, Cote N.Colic is a common problem encountered in equine practice. Alteration of gastrointestinal motility is often the underlying cause for abdominal pain. Gastrointestinal motility can be measured as myoelectric activity, mechanical activity, and transit of intraluminal contents. Regulation of motility is based on a complex interaction between central innervation, autonomic innervation, and the enteric nervous system. Various humoral and neurochemical substances are required to interact flawlessly to allow propulsive motility. Ileus is defined as the absence of propulsive aboral movement of gastroint...
Boscan P, Van Hoogmoed LM, Farver TB, Snyder JR.To evaluate the effects of morphine administration for 6 days on gastrointestinal tract function in healthy adult horses. Methods: 5 horses. Methods: Horses were randomly allocated into 2 groups in a crossover study. Horses in the treatment group received morphine sulfate at a dosage of 0.5 mg/kg, IV, every 12 hours for 6 days. Horses in the control group received saline (0.9% NaCl) solution at a dosage of 10 mL, IV, every 12 hours for 6 days. Variables assessed included defecation frequency, weight of feces produced, intestinal transit time (evaluated by use of barium-filled spheres and radio...
Natalini CC, Polydoro Ada S, Linardi RL.To evaluate the effects of subarachnoidally administered hyperbaric morphine, buprenorphine, and methadone on avoidance threshold to noxious electrical stimulation of the perineal, sacral, lumbar, and thoracic regions in horses. Methods: 6 healthy adult horses. Methods: Horses were assigned to receive subarachnoid administration of hyperbaric morphine (0.01 mg/kg), buprenorphine (0.001 mg/kg), methadone (0.01 mg/kg), or 10% dextrose solution in equal volumes (5 mL). Electrical stimulation was applied every 10 minutes for 60 minutes and every 30 minutes for 120 minutes after subarachnoid inject...
Hollis AR, Ousey JC, Palmer L, Stoneham SJ, Corley KT.Fenoldopam mesylate, a dopamine-1 receptor agonist, has dose- and species-dependent effects on hemodynamics and renal function. The effects of this drug in normotensive neonatal foals have not been reported. Objective: Two doses of fenoldopam would result in distinct changes in the systemic circulation, urine output, and creatinine clearance of neonatal foals. Methods: Six Thoroughbred foals. Methods: Each foal received 2 dosages of fenoldopam (low dose, 0.04 microg/kg/min; high dose, 0.4 microg/kg/min) and a control administration of saline, in a masked, placebo-controlled study. Results: Hig...
Sandersen CF, Detilleux J, de Moffarts B, Van Loon G, Amory H.The aim of this study was to investigate the effect of combined atropine low-dose dobutamine stress test on left ventricular parameters in adult warmblood horses, to establish a potential protocol for pharmacological stress echocardiography. Seven healthy untrained warmblood horses aged 9 to 22 years were used. Heart rate (HR) and left ventricular B- and M-mode dimensions were recorded at baseline and during stress testing with 35 microg/kg atropine IV followed by incremental dobutamine infusion of 2 to 6 microg/kg/min. HR increased significantly (P < .05) during the pharmacological challen...
Bentz BG, Maxwell LK, Erkert RS, Royer CM, Davis MS, MacAllister CG, Clarke CR.The purpose of the study reported here was to describe the bioavailability and pharmacokinetics of acyclovir after intravenous and oral administration to horses. Six healthy adult horses were used in a randomized cross-over study with a 3 x 3 Latin square design. Three treatments were administered to each horse: 10 mg of injectable acyclovir/kg of body weight in 1 L of normal saline delivered as an infusion over 15 minutes; 10 mg of acyclovir/kg in tablets by nasogastric intubation; and 20 mg of acyclovir/kg in tablets by nasogastric intubation. A 2-week washout period was provided between eac...
Gehlen H, Marnette S, Rohn K, Stadler P.The purpose of this study was to determine whether the combination of dobutamine and atropine causes cardiac stress equivalent to treadmill exercise. Therefore, electrocardiography and echocardiography were performed on 10 warmblood horses before, during, and after different cardiac stress tests. Stressors consisted of a standardized treadmill exercise and combined administration of dobutamine (7.5 microg/kg/min) and atropine (5 microg/kg). Maxima heart rates were achieved during the treadmill exercise (175 +/- 10 bpm). After exercise, a rapid decrease in heart rate was observed. Subsequently,...
Kite GC, Stoneham CA, Veitch NC, Stein BK, Whitwell KE.Liquid chromatography-mass spectrometry (LC-MS) analysis of methanol extracts of Oenanthe crocata roots revealed that oenanthotoxin co-eluted with another major polyalkyne, 2,3-dihydro-oenanthotoxin, using the existing high performance liquid chromatography (HPLC) method (isocratic elution from C18 with aqueous methanol) for investigating Oenanthe poisoning. Positive ES or APCI gave [(M+H)-H(2)O](+) and its methanol adduct as major ion species for oenanthotoxin, whereas 2,3-dihydro-oenanthotoxin formed [M+H](+) and its methanol adduct. The two polyalkynes could be chromatographically resolved ...
Gilger BC, Salmon JH, Wilkie DA, Cruysberg LP, Kim J, Hayat M, Kim H, Kim S, Yuan P, Lee SS, Harrington SM, Murray PR, Edelhauser HF, Csaky KG....To determine the feasibility, safety, and effectiveness of an episcleral or deep scleral lamellar sustained release cyclosporine (CsA) device in a naturally occurring animal model of uveitis. Methods: A two-compartment perfusion chamber was used to assess in vitro human and equine scleral permeability of fluorescein, dexamethasone-fluorescein, or CsA. A biodegradable, matrix-reservoir CsA implant was designed, and release rates of CsA were determined in vitro. Tissue CsA levels were measured in eyes with the implant. Horses with equine recurrent uveitis (ERU) received episcleral or deep sclera...
Hubbell JA, Muir WW.The ability to shorten the duration of sedation would potentially improve safety and utility of detomidine. Objective: To determine the effects of tolazoline and atipamezole after detomidine sedation. Objective: Administration of tolazoline or atipamezole would not affect detomidine sedation. Methods: In a randomised, placebo-controlled, double-blind, descriptive study, detomidine (0.02 mg/kg bwt i.v.) was administered to 6 mature horses on 4 separate occasions. Twenty-five mins later, each horse received one of 4 treatments: Group 1 saline (0.9% i.v.) as a placebo control; Group 2 atipamezole...
McKinney AR, Suann CJ, Stenhouse AM.A method was developed for the analysis of the synthetic progestin 17alpha-hydroxyprogesterone caproate in equine plasma following its administration by intramuscular injection. The method employed a reversed-phase solid-phase extraction followed by enol-trimethylsilylation and analysis by gas chromatography/tandem mass spectrometry. The intact ester was detectable in the plasma for up to 2 weeks after a single therapeutic dose, and was found to be stable in equine whole blood for at least 2 months.
Wilson CR, Sauer JM, Carlson GP, Wallin R, Ward MP, Hooser SB.A comparative study of vitamin K(1) 2,3-epoxide reductase (VKOR) activity in vitro was conducted across species. The apparent kinetic constants K(m app), V(max), and Cl(int app) were determined in bovine, canine, equine, human, murine, ovine, porcine, and rat hepatic microsomes. In addition to these enzyme kinetic constants, the IC(50) of warfarin for VKOR was determined in human, murine, porcine, and rat hepatic microsomes. Interspecies differences were observed when comparing the K(m app) (range, 2.41-6.46 microM), V(max) (range, 19.5-85.7 nmol/mg/min), and Cl(int app) (range, 8.2-18.4 ml/mg...
Gallivan GJ, Viel L, McDonell WN.Multiple-breath nitrogen washouts (MBNW) were performed with 29 light horses. Seven normal horses were used to examine the reproducibility, and 22, ranging from normal to severely diseased, were used to examine the changes in chronic obstructive pulmonary disease (COPD) and the effect of a bronchodilator, salbutamol, on the distribution of ventilation. The MBNW were analyzed using the functional residual capacity (FRC), end-tidal N2 concentration of the final breath of the MBNW (FETN2,fb), end-tidal N2 concentration when the cumulative expired volume was equal to body weight (FETN2,bw), lung c...
Goehring LS, Brandes K, Ashton LV, Wittenburg LA, Olea-Popelka FJ, Lunn DP, Soboll Hussey G.Equine herpesvirus-associated myeloencephalopathy is the result of endothelial cell infection of the spinal cord vasculature with equine herpesvirus-1 (EHV-1) during cell-associated viraemia. Endothelial cell infection requires contact between infected peripheral blood mononuclear and endothelial cells. Inflammation generated during viraemia likely upregulates adhesion molecule expression on both cell types increasing contact and facilitating endothelial cell infection. Objective: Evaluating the role of anti-inflammatory drugs in decreasing endothelial cell infection with EHV-1. Methods: In vi...
Pezzanite LM, Chow L, Strumpf A, Johnson V, Dow SW.Antimicrobial resistance and biofilm formation both present challenges to treatment of bacterial infections with conventional antibiotic therapy and serve as the impetus for development of improved therapeutic approaches. Mesenchymal stromal cell (MSC) therapy exerts an antimicrobial effect as demonstrated in multiple acute bacterial infection models. This effect can be enhanced by pre-conditioning the MSC with Toll or Nod-like receptor stimulation, termed activated cellular therapy (ACT). The purpose of this review is to summarize the current literature on mechanisms of antimicrobial activity...
Hikasa Y, Masuda K, Asakura Y, Yamashita Y, Sato C, Kamio M, Miura A, Taniguchi T, Minamizuru N.This study aimed to pharmacologically identify and characterize α2-adrenoceptors and imidazoline (I) receptors (I1- and I2-subtype) on canine, feline, bovine, equine, murine, and leporine platelet membranes. Saturation binding studies with both (3)H-yohimbine and (3)H-clonidine showed that α2-adrenoceptors were expressed on canine, leporine, feline, and murine platelets but not on bovine and equine platelets. In competition studies, the rank order of affinity of 6 compounds for canine platelet α2-adrenoceptors was similar to that of potency at α2A-subtype reported in human platelets. Satur...
Bettembourg V, Dulgheriu D, Haga HA.To determine dexmedetomidine plasma concentrations at two infusion rates in isoflurane anaesthetized horses and compare cardiovascular effects and anaesthetic recovery between treatments. Methods: Prospective, randomized, masked clinical study. Methods: Healthy, adult, client-owned, non-food producing horses presented for castration. Methods: Premedication consisted of acepromazine, romifidine and morphine, and anaesthesia was induced with ketamine and midazolam. The horses were randomized to receive dexmedetomidine 0.5 μg kg hour (treatment DL, n = 7) or 1.75 μg kg hour (treatment DH, n =...
Goetz TE, Manohar M, Magid JH.The objective of the present study was to ascertain whether administration of a second dose of frusemide would attenuate exercise-induced pulmonary hypertension more than a single dose. Right atrial, right ventricular and pulmonary vascular pressures were determined in 7 healthy, sound, exercise-trained Thoroughbred horses at rest and during exercise (14.2 m/s + a 3.5% uphill grade) performed at maximal heart rate (217 +/- 3 beats/min [mean +/- s.e.]). Horses were studied during the following 3 treatments in random order 7 days apart: control (no medication), frusemide single dose (250 mg i.v....
Kastelic JP, Adams GP, Ginther OJ.Luteal progesterone was removed by an injection of prostaglandin F2alpha or bilateral ovariectomy on Day 12 of pregnancy in pony mares. The embryonic vesicle remained mobile in the uterus until loss occurred on Days 13, 13, 15, or 19 in four prostaglandin-treated mares and Days 15, 17, 19, or 26 in four ovariectomized mares. Exogenous progesterone given daily, starting on Day 12, maintained pregnancy until Day 40 in five of five prostaglandin-treated and three of four ovariectomized mares. During two-hour mobility trials on Day 14, embryonic vesicles in mares without luteal or exogenous proges...
Foreman JH, Ruemmler R.Using an adjustable heart bar shoe model of foot pain, the objective of this study was to test the hypothesis that the combined use of phenylbutazone (PBZ) and flunixin meglumine (FM) would prove more efficacious in alleviating lameness than either drug alone. Methods: One hour after induction of lameness at weekly intervals, 8 healthy adult Thoroughbred horses randomly underwent one of 4 i.v. treatments: saline (SAL) placebo (1 ml/45 kg bwt), PBZ (4.4 mg/kg bwt), FM (1.1 mg/kg bwt) or PBZ+FM (at the same dosages as given individually). Heart rate (HR) and lameness score (LS) responses were as...
Busechian S, Conti MB, Sgorbini M, Conte G, Marchesi MC, Pieramati C, Zappulla F, Vitale V, Rueca F.Equine gastric ulcer syndrome (EGUS) is the most common disease of the stomach in horses and treatment is based on the oral administration of omeprazole for at least 28 days. Aim of this study was to compare the efficacy of two formulations of oral omeprazole-powder paste and gastro-enteric resistant granules-in the treatment of naturally occurring gastric ulcers in racehorses. Thirty-two adult racehorses, aged between 2 and 10 years old, with clinical signs of EGUS were included in this blinded, randomized clinical trial. Two gastroscopies were performed to evaluate gastric lesions in the squ...
Prescott JF.Fifty-one isolates of Corynebacterium equi recovered from pigs and horses belonging to two capsular serotypes were tested for susceptibility to antimicrobial agents. No clear differences were detected in sensitivity between isolates of different sources or serotypes. All isolates were sensitive to less than 0.25 micrograms/ml of erythromycin and gentamicin. The following minimum inhibitory concentrations (MICs) of antimicrobial agents were determined for greater than or equal to 90% of isolates: methicillin greater than 16 micrograms/ml, clindamycin 1-2 micrograms/ml, tobramycin less than or e...
James K, Pullar DM, Morton JB, Dalton RG, Nolan B, Woodruff MF.Methods are described for the intravenous administration of equine antilymphocytic globulin (ALG) to renal transplant recipients. The development of circulating antibodies to the equine IgG has been investigated using primary and secondary immunological procedures. The need for primary immunoassay procedures to assess both the immune response and induction of tolerance to equine IgG in ALG treated patients is extensively discussed.
Helal IE, Al-Abbadi HA, El-Daharawy MH, Ahmed MF.Delayed healing associated with distal limb wounds is highly challenging in equine clinical practice. This study aimed to evaluate healing rates between chronic non-granulating wounds of horse distal limbs that were treated with maltodextrin/ascorbic acid gel alone or in combination with povidone-iodine 1% solution and those treated with povidone-iodine 1% only throughout the study period (35 days) in clinical settings. The study was conducted on 18 adult horses (3-15 years old). Based on the treatment regimen utilized, the horses were divided into three groups (n = 6), with each group having ...
Zhang L, Franchini M, Wehrli Eser M, Dip R.Accumulation of extracellular adenosine has been closely associated with human asthmatic responses. However, the relevance of adenosine signalling in equine airways has not previously been investigated. Objective: To determine the expression of adenosine receptors (AR) in bronchoalveolar lavage (BAL) cells and assess the reactivity of these cells to AR ligands ex vivo, employing IL-6 as readout of adenosinergic inflammatory signalling. Methods: Eight horses with varying degrees of lower airway inflammation and 10 healthy controls were analysed. Expression of AR-subtypes in each BAL sample was ...
Harkins JD, Mundy GD, Woods WE, Lehner A, Karpiesiuk W, Rees WA, Dirikolu L, Bass S, Carter WG, Boyles J, Tobin T.Lidocaine is a local anaesthetic agent that is widely used in equine medicine. It is also an Association of Racing Commissioners International (ARCI) Class 2 foreign substance that may cause regulators to impose substantial penalties if residues are identified in post race urine samples. Therefore, an analytical/pharmacological database was developed for this drug. Using our abaxial sesamoid local anaesthetic model, the highest no-effect dose (HNED) for the local anaesthetic effect of lidocaine was determined to be 4 mg. Using enzyme-linked immunosorbent assay (ELISA) screening, administration...
Le Breton A, Lewis N.Assisted reproductive technologies (ARTs) are performed worldwide in the equine industry to produce genetically valuable foals. Among them, ovum pick up (OPU) combined with intra-cytoplasmic sperm injection (ICSI) can now be more efficient than embryo transfer (ET) under optimal conditions. However, OPU is not a benign procedure for the mare and the process is costly. Improved efficiency is therefore in the interest of everyone, maximizing mare welfare and optimizing economics for the client. One of the key factors of success is the antral follicle count (AFC) at the time of OPU and subsequent...
Galinelli NC, Bamford NJ, Erdody ML, Mackenzie SA, Warnken T, Harris PA, Sillence MN, Bailey SR.Due to the high frequency of laminitis reported for both conditions, the relationship between pituitary pars intermedia dysfunction (PPID) and insulin dysregulation (ID), and the potential role of dopamine in modifying insulin secretion, requires further investigation. Objective: To evaluate the effect of pergolide mesylate on insulin sensitivity and postprandial insulin and glucose responses in horses and ponies with ID, both with or without concurrent PPID. Methods: Randomised crossover study. Methods: Sixteen horses and ponies, comprising eight matched pairs (PPID+ID or ID-only), were given...
Usuga A, Vergara AK, Tobón MC, Vargas S, Rojano B, Restrepo G.Maintaining sperm energy homeostasis in vitro is very important to improve the efficacy of stallion sperm preservation. Equine spermatozoa preferentially utilize oxidative phosphorylation over glycolysis to generate ATP. Metformin and rosiglitazone are antidiabetic compounds that enhances metabolic flexibility and glucose utilization. The aim of this study was to evaluate metformin and rosiglitazone supplementation of the freezing medium on quality and oxidative status of thawed stallion semen. A total of 15 ejaculates from five horses were collected and supplemented before freezing with metfo...
Oliveira Orsi R, Zaluski R, de Barros LC, Barraviera B, Pimenta DC, Ferreira Junior RS.Africanized bees have spread across the Americas since 1956 and consequently resulted in human and animal deaths attributed to massive attacks related to exposure from Argentina to the USA. In Brazil, more than 100,000 accidents were registered in the last 5 years with a total of 303 deaths. To treat such massive attacks, Brazilian researchers developed the first specific antivenom against Africanized honey bee sting exposure. This unique product, the first of its kind in the world, has been safely tested in 20 patients during a Phase 2 clinical trial. To develop the antivenom, a standardize...
Onzere CK, Hassan A, Sears K, Kappmeyer LS, Villarino NF, Fry LM, Bastos RG.Theileria haneyi is one of the three known causative agents of equine piroplasmosis. While imidocarb is generally effective in the clearance of the highly pathogenic Theileria equi, it is ineffective in the treatment of T. haneyi. Moreover, co-infection with T. haneyi has been shown to impede the successful treatment of T. equi. Furthermore, tulathromycin and diclazuril have demonstrated inefficacy in eradicating T. haneyi. The absence of an effective therapeutic agent against this parasite represents a significant obstacle in managing equine piroplasmosis. Methods: To address this issue, we e...
Foerster RJ, Wolf G.Equine blood polymorphonuclear leukocytes (PMN) were isolated by buffy coat and hypotonic lysis of residual erythrocytes. A highly reproducible method is described for measuring the uptake of opsonized latex microspheres by equine PMN using flowcytometry. The use of cytochalasin D allowed for differentiation of ingested from attached particles. The kinetics of phagocytosis in vitro is shown for different experimental conditions. We developed an assay for evaluation of phagocytic capacity of PMN which allows the assessment of drugs for their influence on phagocytosis in vivo as well as in vitro...
Allen WR, Stewart F, Cooper MJ, Crowhurst RC, Simpson DJ, McEnery RJ, Greenwood RE, Rossdale PD, Ricketts SW.This research investigates the use of synthetic prostaglandin analogues, specifically ICI-81008 and ICI-79939, in mares for inducing luteolysis, the regression of the corpus luteum, to manage infertility issues. The study […]
Schatzmann U, Tschudi P, Held JP, Muhlebach B.Glyceryl guaiacolate (GGE) was found to be a useful and safe casting agent when given by rapid intravenous infusion. It was administered to premedicated horses under controlled conditions at various concentrations from 10 to 20 per cent GGE solution. The onset and degree of relaxation was dependent only on the speed of infusion. For casting adult horses 350 to 450 ml of 15 per cent solution must be given within 30 to 60 seconds. A slight transient hypoxaemia occurred which seemed to be related to the animal being in lateral recumbency rather than the depressive action of GGE on respiratory fun...
Timko KJ, Hostnik LD, Watts MR, Chen C, Bercz A, Toribio RE, Belknap JK, Burns TA.Insulin dysregulation is a hallmark of equine metabolic syndrome (EMS) and increases the risk for development of laminitis. Accurate diagnosis of insulin dysregulation is crucial for implementation of preventative strategies in this population. The objective was to assess the effects of dexamethasone administration on insulin and glucose dynamics in light-breed horses and assess the agreement of various diagnostic tests for insulin dysregulation [basal [insulin] (BI), oral sugar test (OST), and combined glucose-insulin test (CGIT)]. Fourteen adult light-breed horses. Prospective, experimental ...
Garcia P, Paris AC, Gil J, Popot MA, Bonnaire Y.A sensitive method using LC/ESI-MS(n) has been developed on a quadrupole linear ion trap mass analyser for the detection of nine β(2) agonists (cimaterol, clenbuterol, fenoterol, formoterol, mabuterol, terbutaline, ractopamine, salbutamol and salmeterol) in horse urine. The method consists of solid-phase extraction on CSDAU cartridges before analysis by LC/ESI-MS(n) . The efficiency of extraction combined with the sensitivity and the selectivity of MS(n) allowed the detection of these compounds at pg/mL levels. Administration studies of fenoterol and formoterol are reported and show their pos...
Bohaychuk-Preuss KS, Carrozzo MV, Duke-Novakovski T.To record the cardiopulmonary effects of pleural CO2 positive pressure insufflation in anesthetized horses. Methods: Prospective study. Methods: Seven horses (mean ± standard deviation, 530.9 ± 68.1 kg) undergoing terminal surgery. Methods: Horses were sedated with xylazine. Anesthesia was induced with ketamine-propofol and maintained with isoflurane, positive pressure ventilation, detomidine infusion, and butorphanol with the horses in dorsal recumbency. Baseline measurements were cardiac output, heart rate, pulmonary and systemic arterial and right atrial blood pressures, body temperature,...
Tobin T, Tai CY, O'Leary J, Sturma L, Arnett S.It has recently been suggested that procaine penicillin existed in solution in vitro and in vivo as a "procaine - penicillin" complex rather than as dissociated ions. In vivo, this complexed procaine was considered unavailable for hydrolysis by plasma esterases or for interaction with pharmacologic receptors for procaine. When procaine penicillin was intramuscularly given to horses, about 90% of the procaine in blood drawn from these horses was split at the same rate as authentic procaine or procaine penicillin added to equine blood in vitro. In vitro, procaine and procaine penicillin partitio...
