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.
Hoerdemann M, Smith RL, Hosgood G.To establish and compare the onset and duration of action of 2 local anesthetics based on objective lameness and skin sensitivity assessment. Methods: Interventional crossover experimental trial with balanced randomization. Methods: Eight horses. Methods: Reversible forelimb lameness was induced in 8 horses. A palmar digital nerve block (PDNB) was applied with mepivacaine or lidocaine (both 2%). Quantitative lameness and skin sensitivity data were collected with an inertial sensor system and a force gauge, respectively. The times to lameness resolution/skin desensitization (T1), consistent lam...
Zizzadoro C, Caruso M, Punzi S, Crescenzo G, Zongoli F, Belloli C.Hemodynamic perturbations, partly resulting from abnormal vasoconstriction of digital vessels, have been implicated in the pathogenesis of bovine and equine laminitis. This study compared the responsiveness of isolated bovine (BDA) and equine (EDA) digital arteries to pharmacological agents that stimulate receptor systems involved in the regulation of normal vessel tone. The role of the endothelium and the short- and longer-term effects of an experimentally induced endothelial damage were also evaluated. Species-related differences were found in the vessel reactivity to all of the receptor ago...
Bush J, van den Boom R, Franklin S.Anecdotally, aloe vera is used to treat gastric ulceration, although no studies have yet investigated its efficacy in horses. Objective: To test the hypothesis that aloe vera would be noninferior to omeprazole in the treatment of equine gastric ulcer syndrome. Methods: Randomised, blinded clinical trial. Methods: Forty horses with grade ≥2 lesions of the squamous and/or glandular mucosa were randomly assigned to one of two groups. Horses received either aloe vera inner leaf gel (17.6 mg/kg bwt) b.i.d. or omeprazole (4 mg/kg bwt) s.i.d. for approximately 28 days, after which a repeat gastrosc...
Menozzi A, Pozzoli C, Poli E, Bontempi G, Serventi P, Meucci V, Intorre L, Bertini S.Nonselective antimuscarinic drugs are clinically useful in several pathologic conditions of horses, but, blocking all muscarinic receptor (MR) subtypes, may cause several side effects. The availability of selective antimuscarinic drugs could improve therapeutic efficacy and safety. We aimed to enlighten the role of different MR subtypes by evaluating the effects of nonselective, and selective M, M and M MR antagonists on the contractions of horse jejunum. Segments of circular muscle of equine jejunum, were put into organ baths, connected to isotonic transducers, and the effects on ACh concentr...
Parra N, Jaume M, Boscán K, Hernández A, Mijares A, González M, Alvarado Y, Restrepo J.Trypanosoma equiperdum is the causative agent of dourine, a venereal disease in horses and donkeys. This parasite has a widely distribution, is found in Africa, Asia, Southern and Eastern Europe, Russia, Mexico and Venezuela. The T. equiperdum is morphologically indistinguishable to other Trypanozoon species, however differs from other mammalian trypanosomes due to the fact that it is primarily a tissue parasite, generating cutaneous plaques, swelling of genitalia and neurological signs. The aim of this study was to evaluate the trypanocidal effectiveness of a set of derivatives of thiosemicar...
Mosing M, Auer U, MacFarlane P, Bardell D, Schramel JP, Böhm SH, Bettschart-Wolfensberger R, Waldmann AD.The aim of this study was to evaluate the effect of continuous positive airway pressure (CPAP) on regional distribution of ventilation and dead space in anaesthetized horses. Methods: Randomized, experimental, crossover study. Methods: A total of eight healthy adult horses. Methods: Horses were anaesthetized twice with isoflurane in 50% oxygen and medetomidine as continuous infusion in dorsal recumbency, and administered in random order either CPAP (8 cmHO) or NO CPAP for 3 hours. Electrical impedance tomography (and volumetric capnography (VCap) measurements were performed every 30 minutes. L...
Zak A, Siwinska N, Slowikowska M, Borowicz H, Kubiak K, Hildebrand J, Popiolek M, Niedzwiedz A.There are no available studies describing the possible resistance of strongyles to ivermectin in horses in Poland. One hundred seventy three horses from nine stud farms from South-Western Poland were studied. The effectiveness of ivermectin was studied on the 14th day after ivermectin administration using the fecal egg count reduction test, and a long-term observation of the egg reappearance period was carried out. The fecal study was carried out using a modified McMaster method, which typically detects 20 eggs per gram of stool. The results were subjected to statistical analysis that enabled ...
Vieitez V, Gómez de Segura IÁ, Martin-Cuervo M, Gracia LA, Ezquerra LJ.Lipid emulsion has been reported to be effective for the treatment of local anaesthetic overdoses in rats, dogs and man. Objective: To describe the successful treatment of cardiovascular lidocaine toxicity in a foal with intravenous lipid administration. Methods: Observational study: case report. Methods: An 8-month-old Arabian cross foal was anaesthetised for removal of the right alar fold and nasal plate. Anaesthesia was maintained with isoflurane in oxygen and lidocaine administered with a loading dose followed by a continuous rate infusion (CRI). The anaesthetic period was uneventful and 3...
This work proposes an application of a minimal complexity physiologically based pharmacokinetic model to predict tramadol concentration vs time profiles in horses. Tramadol is an opioid analgesic also used for veterinary treatments. Researchers and medical doctors can profit from the application of mathematical models as supporting tools to optimize the pharmacological treatment of animal species. The proposed model is based on physiology but adopts the minimal compartmental architecture necessary to describe the experimental data. The model features a system of ordinary differential equations...
Castilla-Castaño E, Vischi A, Navarro C, Lecru LA, Ribeiro C, Pradier S, Cadiergues MC.Two open-controlled studies evaluated the tolerance and the efficacy of a 10 mg/mL deltamethrin-based pour-on solution (Deltanil®; Virbac, France) in treating (study 1) and preventing (study 2) natural Damalinia equi infestations in horses. In study 1, seven adult horses received 10 mL of the solution from mane to tail head on day 0 (D0). Four adult horses, living separately, served as non-treated controls. All were naturally infected. Lice burden was recorded by counting the number of live parasites, bilaterally, over seven anatomic regions. Lesional score was based on alopecia, crusts, papu...
Bianco AW, Moore GE, Cooper BR, Taylor SD.Flunixin meglumine (FM) is a commonly used Nonsteroidal anti-inflammatory drug (NSAID) in horses, but clinical efficacy is often unsatisfactory. Ketorolac tromethamine (KT) demonstrates superior efficacy compared to other NSAIDs in humans, but its anti-inflammatory effects have not been investigated in the horse. Safety of repeated dosing of KT has not been evaluated. The first objective was to conduct a dose determination study to verify that a previously described dosage of KT would inhibit Lipopolysaccharide (LPS)-induced eicosanoid production in vitro, and to compare KT effects of this inh...
Monk CS, Jeong SY, Gibson DJ, Plummer CE.Tetracyclines have activity against matrix metalloproteinases (MMP). Oral medications with effects on the ocular surface are of interest in patients where repeated topical dosing is limited. The aim of this study was to characterize the concentration of minocycline in the tears of normal horses after oral administration and to determine if this level directly inhibits MMP activity. Methods: Five healthy adult ponies were administered oral minocycline (Wedgewood Pharmacy; Swedesboro, NJ) at 4 mg/kg every 12 h for 5 days. Tears were collected at T = 2, 26, 50, 56, 74, 80, and 98 h. Tear minocycl...
Boakari YL, Ferreira JC, Canesin HS, Thompson DL, Lima FS, Pantoja JCF, Meira C.The objective of the current study was to evaluate the effects of deslorelin and hCG, two ovulation-inducing therapies, on LH surge and follicle vascularity in mares. Thirty mares were either treated with 1.5 mg IM of deslorelin, 2,500 IU IV of hCG or 2 mL IM of NaCl 0.9% (GnRH, hCG and Saline groups, respectively). Power-flow Doppler examination and blood collection were performed every hour during the first 12 hours after treatment (H0) and every six hours between hours 12 (H12) and 30 (H30) after treatment. Moreover, endpoints were evaluated every hour through the last six hours before ovul...
Von Zup M, Lassaline M, Kass PH, Miller PE, Thomasy SM.Brimonidine is an α2 -adrenergic agonist that decreases aqueous humour production and may increase uveoscleral outflow. It has not been evaluated in normal or glaucomatous equine eyes. Objective: To evaluate the efficacy and safety of brimonidine in lowering intraocular pressure (IOP), alone and in conjunction with timolol, as a treatment for equine glaucoma by comparing IOP in normal equine eyes treated with brimonidine and brimonidine-timolol, respectively, with IOP in control eyes. Methods: A balanced crossover design with 16 horses receiving one of two treatments, brimonidine and brimonid...
Léguillette R, Tohver T, Bond SL, Nicol JA, McDonald KJ.Airway hyperresponsiveness (AWHR), expressed as hypersensitivity (PC R ) or hyperreactivity (slope of the histamine dose-response curve), is a feature of inflammatory airway disease (IAD) or mild equine asthma in horses. Glucocorticoids are used empirically to treat IAD. Objective: To determine whether dexamethasone (DEX) (0.05 mg/kg IM q24h) and inhaled fluticasone (FLUT) (3,000 μg q12h) administered by inhalation are effective in decreasing AWHR, lung inflammation, and clinical signs in horses with IAD. Methods: A randomized crossover study design was used. Eight horses with IAD were assign...
Cuming RS, Abarca EM, Duran S, Wooldridge AA, Stewart AJ, Ravis W, Babu RJ, Lin YJ, Hathcock T.To determine in vitro release profiles, transcorneal permeation, and ocular injection characteristics of a voriconazole-containing thermogel suitable for injection into the subconjunctival space (SCS). In vitro release rate of voriconazole (0.3% and 1.5%) from poly (DL-lactide-co-glycolide-b-ethylene glycol-b-DL-lactide-co-glycolide) (PLGA-PEG-PLGA) thermogel was determined for 28 days. A Franz cell diffusion chamber was used to evaluate equine transcorneal and transscleral permeation of voriconazole (1.5% topical solution, 0.3% and 1.5% voriconazole-thermogel) for 24 hours. Antifungal activit...
Ziegler A, Fogle C, Blikslager A.Nonsteroidal anti-inflammatory drugs work through inhibition of cyclooxygenase (COX) and are highly effective for the treatment of pain and inflammation in horses. There are 2 clinically relevant isoforms of COX. Cyclooxygenase-1 is constitutively expressed and is considered important for a variety of physiologic functions, including gastrointestinal homeostasis. Thus, NSAIDs that selectively inhibit COX-2 while sparing COX-1 may be associated with a lower incidence of adverse gastrointestinal effects. Various formulations of firocoxib, a COX-2-selective NSAID, labeled for use in horses are av...
Frank N, Hermida P, Sanchez-Londoño A, Singh R, Gradil CM, Uricchio CK.Octreotide is a somatostatin analog that suppresses insulin secretion. Objective: We hypothesized that octreotide would suppress insulin concentrations in horses and that normal (N) horses and those with insulin dysregulation (ID) would differ significantly in their plasma glucose and insulin responses to administration of octreotide. Methods: Twelve horses, N = 5, ID = 7. Methods: Prospective study. An oral sugar test was performed to assign horses to N and ID groups. Octreotide (1.0 μg/kg IV) was then administered, and blood was collected at 0, 5, 10, 15, 20, 25, 30, 45, 60, 75, and 90 minu...
Warnken T, Brehm R, Feige K, Huber K.The aim of the study was to analyze key proteins of the equine insulin signaling cascade and their extent of phosphorylation in biopsies from muscle tissue (MT), liver tissue (LT), and nuchal AT, subcutaneous AT, and retroperitoneal adipose tissues. This was investigated under unstimulated (B1) and intravenously insulin stimulated (B2) conditions, which were achieved by injection of insulin (0.1 IU/kg bodyweight) and glucose (150 mg/kg bodyweight). Twelve warmblood horses aged 15 ± 6.8 yr (yr), weighing 559 ± 79 kg, and with a mean body condition score of 4.7 ± 1.5 were included in the s...
Harmon CCG, Hawkins JF, Li J, Connell S, Miller M, Saenger M, Freeman LJ.OBJECTIVE To determine the effects of 3 topically applied treatments (1% silver sulfadiazine cream [SSC], triple antimicrobial ointment [TAO], and hyperosmolar nanoemulsion [HNE]) on microbial counts, exuberant granulation tissue (EGT) development, and reepithelialization of contaminated wounds at the distal aspect of the limbs of horses. ANIMALS 8 healthy adult horses. PROCEDURES A 2.5 × 2.5-cm, full-thickness, cutaneous wound was created at the dorsal aspect of each metacarpus and metatarsus (1 wound/limb/horse), covered with nonadhesive dressing, and bandaged. Wounds were inoculated with b...
Kilborne AH, Hussein H, Bertone AL.OBJECTIVE To investigate effects of hyaluronic acid (HA) or HA combined with chondroitin sulfate (CS) and N-acetyl-d-glucosamine (NAG) by use of a lipopolysaccharide (LPS) in vitro method. SAMPLE Monolayer cultures of synovial cells from 4 adult horses. PROCEDURES Synovial cell cultures were untreated or treated with HA alone or HA-CS-NAG for 24 hours, subsequently unchallenged or challenge-exposed with 2 LPS concentrations (20 and 50 ng/mL) for 2 hours, and retreated with HA or HA-CS-NAG for another 24 hours. Cellular morphology of cultures was evaluated at 0, 24 (before LPS), 26 (after LPS),...
Rutenberg D, Venner M, Giguère S.There is conflicting data regarding the efficacy of tulathromycin for the treatment of foals with bronchopneumonia. Tulathromycin is effective for the treatment of bronchopneumonia in foals and noninferior to the combination of azithromycin and rifampin. A total of 240 foals on a farm endemic for infections caused by Rhodococcus equi. In a controlled, randomized, and double-blinded clinical trial, foals with ultrasonographic pulmonary lesions (abscess score 10-15 cm) were allocated to 3 groups: 1-tulathromycin IM q 7 days (n = 80); 2-azithromycin-rifampin, orally q24h (n = 80); or 3-untreated ...
Brilhante RSN, Bittencourt PV, de Souza Collares Castelo-Branco D, de Melo Guedes GM, de Oliveira JS, Alencar LP, de Aguiar Cordeiro R, Pinheiro M....This study aimed to assess the biofilm-forming ability of Candida spp. from the ocular conjunctiva of horses and to investigate the antifungal susceptibility of these biofilms. Methods: Initially, the biofilm-forming ability of 15 strains was assessed by crystal violet staining, which reveals the fungal biomass adhered to the polystyrene plates, and scanning electron microscopy. Then, the minimum inhibitory concentrations (MICs) of amphotericin B, fluconazole, itraconazole, and caspofungin were initially determined against strains in planktonic form. Afterward, antifungal susceptibility of mat...
Gozalo-Marcilla M, Luna SP, Crosignani N, Filho JNP, Possebon FS, Pelligand L, Taylor PM.To evaluate intravenous (IV) detomidine with methadone in horses to identify a combination which provides sedation and antinociception without adverse effects. Methods: Randomized, placebo-controlled, blinded, crossover. Methods: A group of eight adult healthy horses aged (mean ± standard deviation) 7 ± 2 years and 372 ± 27 kg. Methods: A total of six treatments were administered IV: saline (SAL); detomidine (5 μg kg; DET); methadone (0.2 mg kg; MET) alone or combined with detomidine [2.5 (MLD), 5 (MMD) or 10 (MHD) μg kg]. Thermal, mechanical and electrical nociceptive thresholds were mea...
Deutsch J, Ekiri A, de Vries A.To compare alfaxalone as continuous intravenous (IV) infusion with intermittent IV injections for maintenance of anaesthesia in ponies undergoing castration. Methods: Prospective, randomized, 'blinded' clinical study. Methods: A group of 33 entire male Welsh ponies undergoing field castration. Methods: After preanaesthetic medication with IV detomidine (10 μg kg) and butorphanol (0.05 mg kg), anaesthesia was induced with IV diazepam (0.05 mg kg) followed by alfaxalone (1 mg kg). After random allocation, anaesthesia was maintained with either IV alfaxalone 2 mg kg hour (group A; n ...
Suganuma K, Yamasaki S, Molefe NI, Musinguzi PS, Davaasuren B, Mossaad E, Narantsatsral S, Battur B, Battsetseg B, Inoue N.Dourine is caused by Trypanosoma equiperdum via coitus with an infected horse. Although dourine is distributed in Equidae worldwide and is listed as an internationally important animal disease by the World Organization for Animal Health (OIE), no effective treatment strategies have been established. In addition, there are no reports on drug discovery, because no drug screening system exists for this parasite. A new T. equiperdum strain was recently isolated from the genital organ of a stallion that showed typical symptoms of dourine. In the present study, we adapted T. equiperdum IVM-t1 from...
Maldonado PA, Montoya TI, Acevedo JF, Keller PW, Word RA.Although the positive effects of vaginal estrogens and the selective estrogen receptor modulator, ospemifene (OS), on the vaginal epithelium are well recognized, less is known regarding the effects of these therapies on the lower urinary tract or vaginal muscularis. Clinical evidence suggests that vaginally administered estrogen may improve overactive bladder-related symptoms. The objective of this study was to compare the effects of OS, vaginal conjugated equine estrogens (CEE), or both on the vaginal wall and lower urinary tract in a rat model of menopause. Contractile force of the bladder n...
Calzetta L, Roncada P, di Cave D, Bonizzi L, Urbani A, Pistocchini E, Rogliani P, Matera MG.Equine asthma is a disease characterised by reversible airflow obstruction, bronchial hyper-responsiveness and airway inflammation following exposure of susceptible horses to specific airborne agents. Although clinical remission can be achieved in a low-airborne dust environment, repeated exacerbations may lead to irreversible airway remodelling. The available data on the pharmacotherapy of equine asthma result from several small studies, and no head-to-head clinical trials have been conducted among the available medications. Objective: To assess the impact of the pharmacological interventions...
Liu Y, Uboh CE, Li X, Guan F, You Y, Maylin GA, Zhu F, Soma LR.A rapid and sensitive method for simultaneous screening, quantification and confirmation of 17 barbiturates in horse plasma using liquid chromatography-tandem mass spectrometry is described. Analytes were recovered from plasma by liquid-liquid extraction using methyl tert-butyl ether, separated on a C18 column, and analyzed in negative electrospray ionization mode. Multiple-reaction monitoring was employed for screening and quantification. Confirmation for the presence of the analytes was achieved by comparing ion intensity ratio. The ranges for limits of detection, quantification and confirma...
Gozalo-Marcilla M, Luna SP, Gasthuys F, Pollaris E, Vlaminck L, Martens A, Haspeslagh M, Schauvliege S.To determine the required rate of a detomidine infusion (loading dose 5 μg kg; initial rate 12.5 μg kg hour) added to a constant infusion of methadone (0.2 mg kg; 0.05 mg kg hour) for sedation in standing horses and ponies undergoing elective surgeries with appropriate local anaesthetic techniques. Methods: Prospective, clinical study. Methods: Adult, healthy, client-owned, non-food-producing horses or ponies sedated for elective standing surgeries longer than 45 minutes. Methods: At baseline (in the stables before administration of sedative agents), at 10 minutes after sedation and every 5 ...
Mansel JC, Clutton RE.To examine the relationship between body mass and thoracic dimensions on arterial oxygen tensions (PaO(2)) in anaesthetized horses and ponies positioned in dorsal recumbency. Methods: Prospective clinical study. Methods: Thirty six client-owned horses and ponies, mean [+/-SD (range)] age 8.1 +/- 4.8 (1.5-20) years and mean body mass 467 +/- 115 (203-656) kg. Methods: Before general anaesthesia, food and water were withheld for 12 and 1 hours respectively. Body mass (kg), height at the withers (H), thoracic circumference (C), thoracic depth (length between dorsal spinous process and sternum; D)...
Tolliver SC, Lyons ET, Drudge JH, Stamper S, Granstrom DE.Critical tests were conducted in horses (n = 11) with naturally acquired infections of benzimidazole (BZ)-resistant population-B small strongyles in 1989 and 1990. Anthelmintics administered were thiabendazole (44 mg/kg of body weight, n = 4), oxibendazole (10 mg/kg, n = 3), and oxfendazole (OFZ, 10 mg/kg; n = 4). All compounds were paste formulations administered orally except for 1 of the OFZ treatments, which was a suspension formulation given by stomach tube. Aggregate mean efficacy was calculated for all species of small strongyles, drug-resistant and non-resistant. The highest efficacy w...
Eades SC, Moore JN.Stimulation of alpha 2 adrenergic receptors inhibits colonic motility and may constrict some peripheral vascular beds. Endotoxemia elicits release of sympathetic neurotransmitters and increases sympathetic nerve activity, which may result in stimulation of alpha 2 adrenergic receptors. The objective of this study was to determine whether blockade of alpha 2 adrenergic receptors would restore cecal motility and blood flow during endotoxemia in horses. Strain-gauge force transducers and ultrasonic flow probes were used to measure cecal and colonic mechanical activity and lateral cecal arterial b...
Sangiah S, MacAllister CC, Amouzadeh HR.The basal gastric pH and free acid contents from five young adult healthy horses were determined at one hour intervals for eight hours. The basal gastric pH and free acid contents varied from 1.63 +/- 0.06 to 1.97 +/- 0.11 and 26.42 +/- 4.14 to 17.92 +/- 5.28 mmol litre-1, respectively. Misoprostol, a methylester analogue of prostaglandin (5 micrograms kg-1, orally) produced a time-dependent increase in the basal gastric pH to above 3.5 (P less than 0.05) at three, four and five hours after administration with a concomitant reduction of 80 to 90 per cent in the basal gastric free acid contents...
Blong AE, Epstein KL, Brainard BM.To investigate the in vitro effects of 3 hydroxyethyl starch (HES) solutions on viscoelastic coagulation testing and platelet function in horses. Methods: Blood samples collected from 7 healthy adult horses. Methods: Blood samples were diluted with various crystalloid and HES solutions to approximate the dilution of blood in vivo that occurs with administration of a 10 and 20 mL/kg fluid bolus to a horse (1:8 and 1:4 dilutions, respectively). Diluted samples were analyzed through optical platelet aggregometry, platelet function analysis, thromboelastography, and dynamic viscoelastic coagulomet...
Schlusselhuber M, Torelli R, Martini C, Leippe M, Cattoir V, Leclercq R, Laugier C, Grötzinger J, Sanguinetti M, Cauchard J.Rhodococcus equi, the causal agent of rhodococcosis, is a major pathogen of foals and is also responsible for severe infections in immunocompromised humans. Of great concern, strains resistant to currently used antibiotics have emerged. As the number of drugs that are efficient in vivo is limited because of the intracellular localization of the bacterium inside macrophages, new active but cell-permeant drugs will be needed in the near future. In the present study, we evaluated, by in vitro and ex vivo experiments, the ability of the alpha-helical equine antimicrobial peptide eCATH1 to kill int...
Zholobenko A, Mouithys-Mickalad A, Modriansky M, Serteyn D, Franck T.A recent study showed that silymarin, a standardized extract of S. marianum might be used in the prevention of equine laminitis. We investigated the effects of quercetin and some compounds found in silymarin (silybin, taxifolin and dehydrosilybin) on reactive oxygen species (ROS) production and myeloperoxidase (MPO) release by stimulated equine neutrophils (PMNs) and on MPO activity. All compounds (tested between 100 nm and 100 μm) inhibited superoxide anion production by stimulated PMNs in a dose-dependent manner. Dehydrosilybin and quercetin inhibited superoxide production and MPO release...
Bush J, van den Boom R, Franklin S.Anecdotally, aloe vera is used to treat gastric ulceration, although no studies have yet investigated its efficacy in horses. Objective: To test the hypothesis that aloe vera would be noninferior to omeprazole in the treatment of equine gastric ulcer syndrome. Methods: Randomised, blinded clinical trial. Methods: Forty horses with grade ≥2 lesions of the squamous and/or glandular mucosa were randomly assigned to one of two groups. Horses received either aloe vera inner leaf gel (17.6 mg/kg bwt) b.i.d. or omeprazole (4 mg/kg bwt) s.i.d. for approximately 28 days, after which a repeat gastrosc...
De-Simone SG, Napoleão-Pêgo P, Teixeira-Pinto LA, Melgarejo AR, Aguiar AS, Provance DW.The presence of whole horse IgG in therapeutic snake antivenom preparations of high purity is a contamination that can cause IgE-mediated allergic reactions in patients. In this study, the immunodominant IgE and IgG-binding epitopes in horse heavy chain IgG3 were mapped using arrays of overlapping peptides synthesized directly onto activated cellulose membranes. Pooled human sera from patients with and without horse antivenom allergies were used to probe the membrane. We have demonstrated that, for both cases, individuals produce antibodies to epitopes of sequential amino acids of horse heavy ...
Olave C, Alvarez P, Uberti B, Morales N, Henriquez C, Folch H, Sarmiento J, Moran G.Neutrophils play an important role in the exacerbation and maintenance of severe equine asthma; persistent neutrophil activity and delayed apoptosis can be harmful to surrounding tissues. Tamoxifen (TX) is a nonsteroidal estrogen receptor modulator with immunomodulatory effects and induces early apoptosis of blood and bronchoalveolar lavage neutrophils from horses with acute lung inflammation. This study investigated if the in vitro effects of tamoxifen are produced by its action on nuclear (α and β) and membrane (GPR30) estrogen receptors in healthy equine neutrophils. Results showed that T...
Ammann VJ, Vrins AA, Lavoie JP.The effects of beclomethasone dipropionate on pulmonary function and arterial blood gas values were investigated in horses with chronic obstructive pulmonary disease (COPD). Six mature mares, diagnosed as having COPD based on clinical signs, cytological examination of bronchoalveolar lavage and pulmonary function testing, were used. Beclomethasone dipropionate (3750 microg) was administered b.i.d. for a 2 week period with a metered dose inhaler using a mask. Pulmonary function tests and arterial blood gas analyses were performed at weekly intervals, starting before beclomethasone administratio...
Sykes BW, Sykes KM, Hallowell GD.Interest in Equine Gastric Ulcer Syndrome (EGUS) has recently increased in part due to a growing awareness of the differences between squamous and glandular disease. The pathophysiology and epidemiology of squamous and glandular disease are different and recently it has been shown that the response of glandular gastric ulceration to monotherapy with omeprazole is poor. Given these differences it has been recommended that specific treatment guidelines be formulated for equine glandular disease and that adjunctive therapies be investigated. Along these lines it has been suggested that the additi...
De Clercq D, van Loon G, Baert K, Tavernier R, Croubels S, De Backer P, Deprez P.Good results have been obtained with a human amiodarone (AD) i.v. protocol in horses with chronic atrial fibrillation (AF) and a pharmacokinetic study is required for a specific i.v. amiodarone treatment protocol for horses. Objective: To study the efficacy of this pharmacokinetic based i.v. AD protocol in horses with chronic AF. Methods: Six horses with chronic AF were treated with an adapted AD infusion protocol. The protocol consisted of 2 phases with a loading dose followed by a maintenance infusion. In the first phase, horses received an infusion of 6.52 mg AD/kg bwt/h for 1 h followed by...
Schoster A, van Spijk JN, Damborg P, Moodley A, Kirchgaessner C, Hartnack S, Schmitt S.Fourth-generation cephalosporins can select for extended-spectrum β-lactamase (ESBL)-producing Enterobacteriaceae in horses, but it is unknown to what extent this occurs compared to penicillin/gentamicin combination treatment. The objective was to evaluate the effect of different antimicrobial treatments on faecal shedding and diversity of ESBL-producing Escherichia coli (ESBL-EC) in horses. Upon hospital admission, 86 horses in need of antimicrobial treatment or prophylaxis were randomly allocated to receive penicillin and gentamicin (PG) or cefquinome (CEF). Untreated horses were included a...
Brennan KM, Urschel KL.Dexamethasone is an anti-inflammatory drug commonly used in equine medicine. Insulin sensitivity decreases with prolonged dexamethasone administration, but little information is available about the duration of this side effect after long-term treatment ends. Objective: To determine how long it takes for blood glucose, insulin and markers of insulin sensitivity to return to normal ranges after extended dexamethasone treatment has ceased. Methods: Experimental study. Methods: Eight healthy, mature, mixed-breed horses received 0.04 mg/kg bwt/day oral dexamethasone for 21 days. Blood samples wer...
Wilson SM, Rakhit S, Murdoch R, Pediani JD, Elder HY, Baines DL, Ko WH, Wong PY.Experiments were undertaken using cultured equine sweat gland epithelial cells that express purine receptors belonging to the P2U subclass which allow the selective agonist uridine triphosphate (UTP) to increase the concentration of intracellular free Ca2+ ([Ca2+]i). Experiments using pertussis toxin (Ptx), which inactivates certain guanine-nucleotide-binding proteins (G-proteins), showed that this response consisted of Ptx-sensitive and Ptx-resistant components, and immunochemical analyses of the G-protein alpha subunits present in the cells showed that both Ptx-sensitive (alpha i1-3) and Ptx...
Lisowski ZM, Pirie RS, Blikslager AT, Lefebvre D, Hume DA, Hudson NPH.Post-operative ileus (POI) is a serious condition which any horse undergoing abdominal surgery is at risk of developing, leading to increased hospitalisation time and resulting costs. Advances in the understanding of the development of equine POI are mainly based on human and rodent literature, where manipulation-induced inflammation has been identified as a trigger, with activation of resident muscularis externa macrophages playing a crucial role in the pathophysiology. Despite many pharmacological trials in all species, there is no single completely successful treatment for POI, highlighting...
Brooks AC, Menzies-Gow N, Bailey SR, Cunningham FM, Elliott J.Hypoxia may enhance the deleterious effects of lipopolysaccharide (LPS) in the endotoxaemic horse. This study has examined some of the actions of LPS and hypoxia, alone and in combination, on cultured equine digital vein endothelial cells (EDVEC) and the signalling molecules involved. Methods: EDVEC were exposed to LPS, 5% O(2) and LPS then 5% O(2) for up to 24 h. HIF-1alpha stabilisation, neutrophil adhesion and EDVEC permeability were assessed by immunoblotting, measurement of myeloperoxidase and movement of FITC-dextran, respectively. Pharmacological inhibitors were used to assess the roles...
Van Erck E, Votion D, Art T, Lekeux P.The long-established conventional reference technique (CRT) for measuring respiratory mechanics in horses lacks sensitivity and there is a need for further refinement in new technology, such as the impulse oscillometry system (IOS). Objective: To evaluate the potential use of the IOS as a clinical respiratory function test and compare it to the current CRT in horses suffering from common upper and lower airway dysfunctions. Methods: Six healthy horses were tested before and after induction of a unilateral nasal obstruction (UNO) or transient left laryngeal hemiplegia (LLH). Six heaves-affected...
de Vries A, Brearley JC, Taylor PM.Volatile agent-induced hypotension may contribute to anaesthetic-related morbidity and mortality in horses. Dobutamine is commonly used to support arterial blood pressure (ABP) but little is known about its cardiovascular effects under clinical conditions. The aim of this clinical study was to elucidate the relationship between cardiovascular function and dobutamine infusion in isoflurane-anaesthetized horses. Forty-four horses anaesthetized for a variety of surgical procedures were studied. Premedication with acepromazine, methadone and detomidine was followed by induction of anaesthesia with...
Bertone AL, Tremaine WH, Macoris DG, Simmons EJ, Ewert KM, Herr LG, Weisbrode SE.To evaluate clinical safety of administration of injectable enrofloxacin. Methods: Randomized controlled clinical trial. Methods: 24 adult horses. Methods: Healthy horses were randomly allocated into 4 equal groups that received placebo injections (control) or IV administration of enrofloxacin (5 mg/kg [2.3 mg/lb], 15 mg/kg [6.8 mg/lb], or 25 mg/kg [11.4 mg/lb] of body weight, q 24 h) for 21 days. Joint angles, cross-sectional area of superficial and deep digital flexor and calcaneal tendons, carpal or tarsal osteophytes or lucency, and midcarpal and tarsocrural articular cartilage lesions wer...
Schwarzwald CC, Hamlin RL, Bonagura JD, Nishijima Y, Meadows C, Carnes CA.Although atrial arrhythmias are clinically important in horses, atrial electrophysiology has been incompletely studied. Objective: Standard electrophysiologic methods can be used to study drug effects in horses. Specifically, the effects of diltiazem on atrioventricular (AV) nodal conduction are rate-dependent and allow control of ventricular response rate during rapid atrial pacing in horses undergoing quinidine treatment. Methods: Fourteen healthy horses. Methods: Arterial blood pressure, surface electrocardiogram, and right atrial electrogram were recorded during sinus rhythm and during pro...
Casella S, Giudice E, Giannetto C, Marafioti S, Piccione G.The purpose of this study was to evaluate in vitro the effects of hydrocortisone and aminophylline on adenosine diphosphate (ADP)-induced platelet aggregation in horses. Blood samples from 30 healthy Thoroughbred horses were collected by via jugular venipuncture to assess platelet aggregation. Platelet-rich and platelet-poor plasma were prepared from all samples by centrifugation and divided into three different aliquots. In the first aliquot, platelet aggregation was measured after platelet activation with 1 µM and 0.5 µM ADP (Group A). In the other two aliquots, the effect of a 10 min prei...
Smith G, Bertone AL, Kaeding C, Simmons EJ, Apostoles S.To evaluate the effect of topically applied dimethylsulfoxide (DMSO) on lipopolysaccharide (LPS)-induced synovitis in the mid-carpal joint. Methods: 6 sound, healthy, adult horses (12 carpi). Methods: In a double-blinded, crossover, paired study with a 1-week washout period, mid-carpal joints were allocated to group 1 (DMSO, n = 6) or group 2 (control, n = 6). Each joint was injected with 1.3 ml (0.0125 ng/dl) of LPS to induce synovitis. For group-1 joints, DMSO gel (15 g; 90%) was applied after injection of LPS and at 12-hour intervals for 60 hours. Joints of group 2 received LPS, but not DMS...
Trumble TN.In horses, lameness is often attributable to some degree of osteoarthritis (OA), a complex disease process that is highlighted by eventual degradation of articular cartilage. Conventional therapies for OA in horses are designed to relieve pain and discomfort and often include pharmacologic intervention with nonsteroidal anti-inflammatory drugs or intra-articular steroids. Oral administration of nutraceutical products to the horse is common and easy and is perceived to be a benign treatment for OA in horses. The main goal for use of nutraceuticals is to use them in OA cases to attempt to lower ...
Sysel AM, Pleasant RS, Jacobson JD, Moll HD, Modransky PD, Warnick LD, Sponenberg DP, Eyre P.Amphotericin B-induced synovitis of the left tarsocrural joint was used to create a grade 3 of 4 lameness in 11 horses. Caudal epidural catheters were placed and advanced to the lumbosacral region. Baseline heart and respiratory rates were recorded and horses were videotaped at a walk and trot. Morphine sulphate (0.2 mg/kg) and detomidine hydrochloride (30 micrograms/kg) were administered to treated horses (n = 8) through the epidural catheter; an equivalent volume of physiologic saline solution was administered to control horses (n = 3) through the catheter. At hourly intervals after epidural...
Edwards GB.Intraoperative techniques for assessing the viability of ischaemic bowel are discussed. Intravenous administration of sodium fluorescein appears useful but further investigation of the method is required. Methods of resection and anastomosis of small intestine are described and illustrated, including the use of automatic stapling instruments.
Zak A, Siwinska N, Slowikowska M, Borowicz H, Kubiak K, Hildebrand J, Popiolek M, Niedzwiedz A.There are no available studies describing the possible resistance of strongyles to ivermectin in horses in Poland. One hundred seventy three horses from nine stud farms from South-Western Poland were studied. The effectiveness of ivermectin was studied on the 14th day after ivermectin administration using the fecal egg count reduction test, and a long-term observation of the egg reappearance period was carried out. The fecal study was carried out using a modified McMaster method, which typically detects 20 eggs per gram of stool. The results were subjected to statistical analysis that enabled ...
Strubbe DT, Brooks DE, Schultz GS, Willis-Goulet H, Gelatt KN, Andrew SE, Kallberg ME, MacKay EO, Collante WR.Ulcerative keratitis is a common and potentially blinding ocular disease of horses, capable of progressing to corneal perforation in as little as 24 h. This rapid stromal degeneration is mediated in part by exogenous and endogenous proteinases. We measured and compared the concentrations of two matrix metalloproteinases (MMP-2 and MMP-9) and a serine proteinase (neutrophil elastase) present in the precorneal tear film of normal horses and horses with rapidly progressing ulcerative keratitis. Precorneal tear film samples were collected from 23 ulcerated and 21 unaffected eyes of 23 horses with ...
