In vivo studies involving horses refer to research conducted within living organisms to understand various biological processes, disease mechanisms, and therapeutic interventions in equine species. These studies provide insights into the physiological and pathological responses of horses under natural conditions. In vivo research encompasses a range of investigations, including pharmacokinetics, disease modeling, and the evaluation of treatment efficacy. It often involves the use of controlled environments to simulate real-life scenarios while observing the effects of specific variables on equine health. This page gathers peer-reviewed research articles and scholarly studies that explore the methodologies, findings, and implications of in vivo research in horses, contributing to the advancement of equine science and veterinary medicine.
Pösö AR, Eklund-Uusitalo S, Hyyppä S, Pirilä E.In response to stress, cells synthesise heat shock proteins (HSP) to maintain protein homeostasis. To study whether exercise and training induce expression of HSP72 in the middle gluteal muscle, 10 Finnhorses performed a submaximal 60 min exercise test on a treadmill. Test A was performed after 3 months of training, and the other two tests 2 (B) and 5 (C) weeks later. Blood samples were taken during and after the tests, and biopsy samples before, immediately after and 23 h after each test. HSP72 mRNA was analysed using a digoxigenin-labelled probe. Blood lactate concentration in the 3 tests va...
Dunnett M, Harris RC, Dunnett CE, Harris PA.This study was undertaken as part of a larger investigation into carnosine metabolism and function in the Thoroughbred horse. More specifically, we wished to evaluate plasma carnosine concentration as a potential indicator of muscle carnosine status. In contrast to man, carnosine is present in equine plasma where its presence is consistent with the absence of plasma carnosinase. A significant effect of age on plasma carnosine concentration in resting Thoroughbred horses was observed. Values in horses age 3 years and older were 113-14.1 micromol/l, whereas concentrations in foals and yearlings ...
Harmegnies NF, Duvivier DH, Vandenput SN, Art T, Lekeux PM, Votion DM.This study aimed to compare exercise-induced pulmonary perfusion redistribution in healthy vs. 'heavey' horses using scintigraphy, a minimally invasive technique. Six healthy (A) and 5 'heavey' horses in remission (B(I)) and during clinical signs of disease (B(II)) were investigated. Dimensions of the exercising pulmonary perfusion (QE) images were expressed in percent of the resting perfusion (QR) images. Computed QE to QR ratios (QE/QR) images enabled the definition of the region more perfused at exercise than at rest (R1). In all groups, exercise induced a major enlargement of the Q image b...
Boffi FM, Cittar J, Balskus G, Muriel M, Desmaras E.Apoptosis or programmed cell death is a genetically controlled response of cells to commit suicide and is associated with DNA fragmentation or laddering. The common inducers of apoptosis include Ca2+i and oxygen free radicals/oxidative stress, which are also implicated in the pathogenesis of exercise-induced myopathies. To examine training-induced apoptosis, Thoroughbred horses were subjected to 3 months training programme on a treadmill. At the end of the training programme venous blood samples were taken for a creatine kinase (CK) assay. In addition, muscle biopsy samples were obtained for a...
Orth MW, Peters TL, Hawkins JN.Glucosamine and chondroitin sulphate in many animal and human trials has improved joint health. In vitro studies are beginning to clarify their mode of action. The objective of this research was to: 1) determine at what concentrations glucosamine-HCl (GLN) and/or chondroitin sulphate (CS) would inhibit the cytokine-induced catabolic response in equine articular cartilage explants and 2) to determine if a combination of the 2 was more effective at inhibiting the catabolic response than the individual compounds. Articular cartilage was obtained from carpal joints of horses (age 1-4 years). Carti...
Art T, Tack S, Kirschvinck N, Busoni V, Votion D, Freeman K, Lekeux P.This study aimed at measuring the functional consequences and the pulmonary cytology changes following a simulation of pulmonary haemorrhage. Pulmonary function tests including lobeline-induced hyperventilation, cytology of tracheo-bronchial wash (TBW) and thoracic radiographs were performed before, as well as 1, 7, 14 and 28 days after, the instillation of 300 ml of blood into the lungs of 4 horses deemed free of exercise-induced pulmonary haemorrhage (Group 1). Control data (Group 2) were obtained by instilling the same volume of saline into the lungs of the same horses in a crossover design...
Guillaume D, Bruneau B, Briant C.The effects of two GnRH antagonists were tested in order to delay and/or synchronise ovulation in mares. Five mares received Antarelix (0.01 mg.kg(-1)), 5 mares received Cetrorelix (the same dose), 5 mares (control mares) received the vehicle intravenously, twice daily, for 8 days from the day the largest follicle reached 22 mm following prostaglandin administration. Ovulation was postponed in all mares injected with Antarelix (19.4 +/- 1.2 days after the beginning of the treatment) and in 2/5 mares injected with Cetrorelix (20 +/- 1 days) vs. 6.2 +/- 0.4 days in control mares. During the trea...
Colahan PT, Kollias-Bakert C, Leutenegger CM, Jones JH.Physical exertion is a stimulus for the upregulation of cytokine production including IL-1beta, IL-1ra, IL-2, IL-4, IL-6, IL-10 and TNF-alpha in horses. To investigate that hypothesis, we initiated training of 5 stall-rested Thoroughbreds. Blood samples were drawn before and weekly during training. The relative transcription of mRNA within the leucocytes was measured using real time TaqMan quantitative PCR. The training protocol was walking (3 min), trotting (3 min) and cantering/galloping (6 min) increasing in intensity weekly (6 to 12 m/s) and culminating in an intense exercise period. Compa...
Guo X, Sugita S.Four cell types including the bipolar, amacrine, horizontal and Muller cells were investigated quantitatively in the inner nuclear layer of the retina in the horse. Cells were identified on the basis of the morphology and distribution of processes leaving from their somata, cytological features and positional features. The average percentages of the above 4 cell types were 44%, 24%, 1% and 29%, respectively. The average total cell densities in the inner nuclear layer in the visual streak, the nasal and temporal regions, the dorsal and ventral regions of the retina were also estimated. It is ex...
Stock AE, Bouchard N, Brown K, Spicer AP, Underhill CB, Doré M, Sirois J.In contrast to other species, the preovulatory rise in gonadotropins in mares causes a remarkable expansion of the entire granulosa cell layer in vivo, suggesting that hyaluronan (HA) synthesis may be regulated in mural granulosa cells in this species. The objectives of this study were to clone and characterize equine hyaluronan synthase 2 (HAS2) and investigate the regulation of its transcript and of HA synthesis in equine follicles during human chorionic gonadotropin (hCG)- induced ovulation. Results showed that the equine HAS2 cDNA contains a 5'-untranslated region of 436 bp, an open readin...
Nieto JE, Spier S, Pipers FS, Stanley S, Aleman MR, Smith DC, Snyder JR.To compare effects of a commercially available omeprazole paste and a compounded omeprazole suspension on healing of gastric ulcers in Thoroughbred racehorses in active training. Methods: Randomized controlled trial. Methods: 32 horses with gastric ulcers. Methods: Horses were assigned to 2 groups on the basis of endoscopic gastric ulcer severity. Group-1 horses were treated with omeprazole suspension for 30 days and with omeprazole paste for an additional 30 days. Group-2 horses were treated with omeprazole paste for 30 days and omeprazole suspension for an additional 30 days. Serum omeprazol...
de Freitas CM, Leite RC, Lopes CM, Rodrigues DS, Paz GF, de Oliveira PR.Some reproductive parameters of adult stages of Amblyomma cajennense ticks were studied. The capacity of virgin females to reproduce by parthenogenesis was evaluated, during an experimental infestation, in absence of males, on a horse (Equus cabalus). Ticks were spread either completely free or in limited sites on the body of the animal. The engorged virgin females showed longer feeding periods and lighter body weights than those that had been fertilized. Some of these unmated females produced smaller egg masses, which had no embryonary development. On the other hand, females that had been ins...
McKellar QA, Gokbulut C, Muzandu K, Benchaoui H.The present study was designed to describe the pharmacokinetics and fecal excretion of fenbendazole (FBZ) and fenbendazole sulphoxide (FBZSO) and their metabolites in horses, to investigate the effects which concurrent feeding has on the absorption and pharmacokinetics of FBZ, and to determine the effect of coadministration of the metabolic inhibitor piperonyl-butoxide on the in vivo pharmacokinetics and in vitro liver microsomal metabolism of sulfide and sulfoxide benzimidazoles. The effect of piperonyl-butoxide on the enantiomeric genesis of the sulfoxide moiety was also investigated. Follow...
Barnés CM, Petoud S, Cohen SM, Raymond KN.The ability of ferritin as an Fe(II) detoxifier and Fe(III) storage protein is limited by its ability to recognize and incorporate Fe(II), which is then oxidized and mineralized at internal protein sites. The Cr(III) amine complex [Cr(N(CH(2)CH(2)NH(2))(3)(H(2)O)(OH)](2+) [abbreviated as Cr(TREN)] is a kinetically inert inhibitor of iron incorporation and mineralization in ferritin. Unlike other inhibitors, Cr(TREN) can only exchange its two aqua/hydroxy ligands. Competition studies between Cr(TREN) and Tb(III) binding have been performed in horse spleen ferritin (HoSF) to probe uptake of Fe(I...
Palaniappan RU, Chang YF, Jusuf SS, Artiushin S, Timoney JF, McDonough SP, Barr SC, Divers TJ, Simpson KW, McDonough PL, Mohammed HO.A clone expressing a novel immunoreactive leptospiral immunoglobulin-like protein A of 130 kDa (LigA) from Leptospira interrogans serovar pomona type kennewicki was isolated by screening a genomic DNA library with serum from a mare that had recently aborted due to leptospiral infection. LigA is encoded by an open reading frame of 3,675 bp, and the deduced amino acid sequence consists of a series of 90-amino-acid tandem repeats. A search of the NCBI database found that homology of the LigA repeat region was limited to an immunoglobulin-like domain of the bacterial intimin binding protein of Esc...
Carstanjen B, Lepage OM, Detilleux J, Duboeuf F, Amory H.To evaluate the usefulness of multisite quantitative ultrasonography for noninvasive assessment of bone in horses. Methods: 12 healthy horses and both forelimbs from 8 clinically normal horses. Methods: For in vivo measurements, various regions of interest (ROI) were examined on the third metacarpal bone, radius, and tibia. Precision error for speed of sound (SOS) measurements was obtained by measuring each ROI of 4 horses 10 times with probe repositioning. Additionally, 3 operators measured each aspect of the third metacarpal bone of 6 horses 5 times each. For ex vivo measurements, third meta...
Howe L, Leroux C, Issel CJ, Montelaro RC.Equine infectious anemia virus (EIAV) infection of horses is characterized by well-defined waves of viremia associated with the sequential evolution of distinct viral populations displaying extensive envelope gp90 variation; however, a correlation of in vivo envelope evolution with in vitro serum neutralization phenotype remains undefined. Therefore, the goal of the present study was to utilize a previously defined panel of natural variant EIAV envelope isolates from sequential febrile episodes to characterize the effects of envelope variation during persistent infection on viral neutralizatio...
Steinman A, Isoherranen N, Ashoach O, Soback S.Gentamicin pharmacokinetics has not been studied in horses. Pharmacokinetics of gentamicin C1, C1a and C2 components following i.v. administration of total gentamicin at 6.6 mg/kg bwt to 6 healthy mature horses was determined. Significant differences in clearance, half-life (t 1/2), and mean residence time (MRT) between the gentamicin Cia and the 2 other components were found. The total body clearance (CL) of gentamicin C1a was 1.62 +/- 0.50 ml/min x kg and similar to the glomerular filtration rate (GFR) reported for horses. The CL of gentamicin C1 and C2 were 1.03 +/- 0.08 ml/min x kg and 1.1...
van Hoogmoed LM, Harmon FA, Stanley S, White J, Snyder J.The objective of this study was to determine if a correlation exists between the presence of nitric oxide and prostaglandin release in the equine ventral colon smooth muscle, since this relationship may accentuate the inflammatory process during intestinal injury. Tissue was collected from the ventral colon, cut into muscle strips oriented along the circular, longitudinal and taenial layers, and mounted in a tissue bath system. Samples of the bath fluid were collected before, following electrical field stimulation (EFS), and following EFS in the presence of L-NAME, a nitric oxide synthase inhi...
Van hoogmoed LM, Snyder JR.Thermography is a non-contact, non-invasive technique that detects surface heat emitted as infrared radiation. Because skin temperature reflects the status of underlying tissue metabolism and blood circulation, abnormal thermal patterns can signify areas of superficial inflammation. The objective of this study was to determine if thermography could detect the injection of analgesic and neurolytic agents and surgical palmar digital neurectomy. Procedures evaluated include injection of the lumbar region, suspensory ligaments, tibial nerve, palmar digital nerves, and palmar digital neurectomy. Th...
Lopes MA, Walker BL, White NA, Ward DL.Although large intestine impactions are commonly treated with i.v. fluids combined with the osmotic laxative MgSO4, enteral fluids are less expensive and also appear to be efficacious for impactions. Therefore, this study was conducted to compare the systemic and gastrointestinal effects of enteral fluids with the changes produced by i.v. fluids combined with MgSO4. Four horses with a fistula in the right dorsal colon alternately received both treatments in 2 periods one week apart. Sixty litres of fluids were administered continuously (10 l/h) through a venous catheter or a nasogastric tube. ...
Belloli C, Crescenzo G, Lai O, Carofiglio V, Marang O, Ormas P.The objective of this study was to determine the pharmacokinetic behaviour of imidocarb in horses following a single i.m. injection at the dose commonly administered to treat Babesia caballi infections or to prevent babesiosis. Eight horses were injected i.m. with a single dose of 2.4 mg imidocarb dipropionate/kg bwt and blood, faecal, urine and milk samples were collected. For imidocarb determination, a high-performance liquid chromatographic method (HPLC) was used after weak cation-exchange solid phase, or liquid-liquid, extraction procedures. Twelve hours after treatment, no detectable plas...
Pusterla N, Pusterla JB, Spier SJ, Puget B, Watson JL.The SNAP Foal IgG test (IDEXX) as evaluated for its accuracy and usefulness by measuring blood samples collected from 42 foals between 24 and 48 hours after birth. The results were compared with the single radial immunodiffusion (SRID) test as the reference method. The SNAP test was quick and easy to perform, and the results were similar to those obtained by SRID in 64 per cent of the samples. The best results were found with low ( 800 mg/dl) concentrations of immunoglobulin G, with an accuracy of 80 per cent and 89 per cent, respectively. The intermediate concentrations were usually lower whe...
Spirito F, Charlesworth A, Linder K, Ortonne JP, Baird J, Meneguzzi G.Recent achievements in the genetic correction of keratinocytes isolated from patients with junctional epidermolysis bullosa have paved the way to a gene therapy approach for the disease. Because gene therapy protocols require preclinical validation in animals, we have characterized spontaneous animal models of junctional epidermolysis bullosa. In this study we have elucidated the genetic basis of the hereditary junctional mechanobullous disease in the Belgian horse, a condition characterized by blistering of the skin and mouth epithelia, and exungulation (loss of the hoof). Immunofluorescence ...
Lorenzo-Figueras M, Jones G, Merritt AM.To assess gastric tone in the proximal portion of the stomach in horses during and after ingestion of 4 diets (2 diets of grain and 2 diets of hay). Methods: 6 adult horses. Methods: A polyester bag with a volume of approximately 1,600 ml was inserted through a gastric cannula into the proximal portion of the stomach of each horse. Internal pressure of the bag was maintained at 2 mm Hg by use of an electronic barostat, and changes in bag volume were recorded before, during, and after horses consumed diets of grain or hay. Each horse was fed 0.5 and 1.0 g of grain/kg and 0.5 and 1.0 g of hay/kg...
Brosnan RJ, LeCouteur RA, Steffey EP, Imai A, Kortz GD.To develop a method for surgical placement of a commercial microsensor intracranial pressure (ICP) transducer and to characterize normal ICP and cerebral perfusion pressures (CPP) in conscious adult horses. Methods: 6 healthy castrated male adult horses (1 Holsteiner, 1 Quarter Horse, and 4 Thoroughbreds). Methods: Anesthesia was induced and maintained by use of isoflurane as the sole agent. Catheters were inserted percutaneously into the jugular vein and carotid artery. A microsensor ICP transducer was inserted in the subarachnoid space by means of right parietal craniotomy. The burr hole was...
Faleiros RR, Macoris DG, Alessi AC, Saquetti CH, Rasera L.To determine the effect of experimental intraluminal distention on microvascular perfusion of the small colon in horses. Methods: 6 mixed-breed healthy horses (mean age [+/- SDI, 9.1 +/- 2 years). Methods: Under general anesthesia, the small colon was exposed by celiotomy and 3 segments were demarcated. In 1 of these segments, intraluminal obstruction was created by placement of a latex balloon inflated to a pressure of 40 mm Hg (obstructed segment). The other segments were the sham-operated segment and the control segment. Microvascular perfusion was evaluated in the mucosal, submucosal, musc...
Evans MJ, Kitson NE, Alexander SL, Irvine CH, Turner JE, Perkins NR, Livesey JH.We wish to use a gonadotrophin-releasing hormone (GnRH) antagonist in the mare as a tool for investigating the control of the oestrous cycle. The aim of this study was to test the effectiveness of the antagonist cetrorelix by testing both in vitro, using perifused equine anterior pituitary cells, and in vivo in seasonally acyclic mares. Pituitary cells were prepared and after 3-4 days incubation, loaded onto columns and given four pulses of GnRH (at 0, 30, 60 and 90 min; dose-response study). After the second GnRH pulse, infusion of cetrorelix began (0, 100, 1000 and 2000 pmol/l) and continued...
Pinto CR, Paccamonti DL, Eilts BE, Short CR, Godke RA.Recent studies suggest that nitric oxide (NO) may have a role in regulating ovarian physiology. To investigate the role of NO during ovulation in mares, inhibitors of the nitric oxide synthase (NOS) were administered to estrous mares. Forty cycling mares (20 horses and 20 pony mares) were allotted to one of the three treatment groups. Once a follicle was at least 27 mm in diameter, but smaller than 35 mm, mares were given one of the following treatments: saline solution 0.9% (n = 20, w/v, i.v., every 12 h), Nomega-nitro-L-arginine methyl ester hydrochloride (L-NAME; n = 10, 148 micromol/kg, i....
von Reitzenstein M, Callahan MA, Hansen PJ, LeBlanc MM.An experiment was conducted to determine whether the uterotonic effects of oxytocin, a drug used to treat mares that have a delay in uterine clearance were affected by the sedative detomidine (an alpha2-agonist), a drug used to treat fractious mares. An additional objective was to identify propagation patterns of uterine contractions and determine whether these patterns differed between normal mares and mares with delayed uterine clearance (DUC). Intrauterine pressure was measured in five reproductively normal mares and four mares with DUC during estrus using an 8-F Milar catheter with two dis...
Raidal SL, Taplin RH, Bailey GD, Love DN.To evaluate the administration of procaine penicillin prior to or during confinement with head elevation as a means of reducing the associated accumulation of inflammatory lower respiratory tract secretions and increased numbers of bacteria within the lower respiratory tract of confined horses. Methods: Two experiments were conducted to evaluate the efficacy of different dose rates and dosing frequencies. In experiment A a single low dose (15,000 IU/kg) of procaine penicillin was administered to four horses immediately prior to confinement with head elevation for 48 hours. The systemic leucocy...
Ginther OJ, Pierson RA.A linear-array ultrasound scanner with a 5-MHz transducer was evaluated for studying follicular and luteal status in mares, and the ultrasonic properties of equine ovaries were characterized. Follicular diameters were estimated in vivo and after removing and slicing six ovaries. Correlation coefficients between the two kinds of determinations were 0.91 for number of follicles >/=2 mm in diameter and 0.95 for diameter of largest follicle. The ovaries of five mares were examined daily until all mares had been examined from three days before an ovulation to three days after the next ovulation....
Widenhouse TV, Lester GD, Merritt AM.To determine the effect of pH with or without pepsin or taurocholic acid on the bioelectric properties of gastric squamous mucosa in horses. Methods: Gastric tissues obtained from 16 adult horses that did not have evidence of gastric disease. Methods: Bioelectric properties of squamous mucosa were determined, using modified Ussing chambers. Tissues then were exposed to mucosal pepsin (1 mg/ml) or taurocholic acid (2.5 mM) under neutral (pH 74) or acidic (pH 1.7) conditions. Results: Exposure of mucosal sheets to an acidic pH resulted in an immediate and sustained decrease in transmembrane pote...
Peyrou M, Bousquet-Melou A, Laroute V, Vrins A, Doucet MY.Enrofloxacin and marbofloxacin are two veterinary fluoroquinolones used to treat severe bacterial infections in horses. A repeated measures study has been designed to compare their pharmacokinetic parameters, to investigate their bioavailability and to estimate their absorbed fraction and first-pass effect by using plasma, urinary and metabolite data collected from five healthy mares. Clearance and V(d(ss)) were greater for enrofloxacin (mean +/- SD = 6.34 +/- 1.5 mL/min/kg and 2.32 +/- 0.32 L/kg, respectively) than for marbofloxacin (4.62 +/- 0.67 mL/min/kg and 1.6 +/- 0.25 L/kg, respectively...
Lucas Castillo JA, Gozalo-Marcilla M, Werneck Fonseca M, Possebon FS, da Rosa AC, de Araujo Aguiar AJ.Information on appropriate protocols for sedation of Nordestino donkeys is scarce. Objective: To evaluate the sedative and cardiorespiratory effects of low doses of intravenous (i.v.) xylazine with and without acepromazine in 'Nordestino' donkeys. Methods: Seven healthy female Nordestino donkeys (150 ± 18 kg) were included in this blinded, randomised, crossover experiment. Methods: Four treatments were administered, consisting of two i.v. injections, at baseline (T0, 1st injection) and 15 min later (T15, 2nd injection). Treatments included acepromazine 0.05 mg/kg bwt + saline (AS), saline + x...
Nieto JE, Van Hoogmoed LM, Spier SJ, Vatistas NJ, Snyder JR, Timmerman BL.To use an extracorporeal circuit to evaluate effects of intraluminal distention on the jejunum of healthy horses. Methods: 2 jejunal segments from each of 5 horses. Methods: Jejunal segments were harvested and maintained in an extracorporeal circuit. One segment was subjected to distention (intraluminal pressure, 25 cm H2O) followed by decompression, and 1 segment was maintained without distention. The influence of distention-decompression on vascular resistance was calculated. Mucosal permeability was evaluated by measuring the clearance of albumin from blood to lumen. After distention and de...
Vergari C, Pourcelot P, Ravary-Plumioën B, Dupays AG, Jacquet S, Audigié F, Denoix JM, Laugier P, Mitton D, Crevier-Denoix N.Equine superficial digital flexor tendons (SDFT) are often injured, and they represent an excellent model for human sport tendinopathies. While lesions can be precisely diagnosed by clinical evaluation and ultrasonography, a prognosis is often difficult to establish; the knowledge of the injured tendon's mechanical properties would help in anticipating the outcome. The objectives of the present study were to compare the axial speed of sound (SOS) measured in vivo in normal and injured tendons and to investigate their relationship with the tendons' mechanical parameters, in order to assess the ...
Allen GK, Campbell-Beggs C, Robinson JA, Johnson PJ, Green EM.Six, clinically healthy horses, of mixed age and sex, were infused via a jugular venous catheter with 100 ml of pyrogenfree sterile saline (PFSS; 0.9% NaCl). Animals were infused with Escherichia coli O55:B5 endotoxin (total dose = 50 ng/kg bwt), 24 (LPS-1) and 48 h (LPS-2) after PFSS infusion. Blood was collected before, and every 15 min after, each infusion for the first 8 h and then every 2 h for the following 14 h. Clinical responses (rectal temperature, heart rate, respiration rate and blood pressure) were determined before and every 4 h after each infusion for 20 h. Geometric mean anti-e...
The study evaluated the effectiveness of a commercially available polyherbal dewormer to control intestinal strongyles in naturally infected donkeys. The animals were allotted to two groups: treated with the herbal dewormer (n=8) according to manufacturer recommendations and untreated control group (n=6). Fecal samples were taken from each animal on days 0 (day of treatment), 14, 21 (day of second additional treatment), 35, and 42. Faecal egg count reduction tests showed very negligible or no reduction in number of strongyle eggs for donkeys in the phytotherapeutic treatment group compared to ...
Robinson P, Williams KJ, Sullins KE, Arnoczky SP, Stick JA, Robinson NE, de Feijter-Rupp H, Derksen FJ.Trans-endoscopic laser surgery, such as unilateral laser-assisted ventriculocordectomy (LVC), has gained popularity in the treatment of RLN because a laryngotomy incision or general anaesthesia are not required. However, removal of the vocal fold and ventricle takes considerable laser energy and could cause collateral tissue damage, including injury to the adjacent laryngeal cartilages. Objective: To document the histological effects of laser surgery on laryngeal tissues in horses that have undergone LVC for the treatment of laryngeal hemiplegia (LH). Methods: Six horses were used: 4 with expe...
Maninchedda U, Lepage OM, Gangl M, Benredouane K.To (1) describe ultrasound-guided percutaneous introduction of a transarterial angiographic catheter into the common carotid artery (CCA); (2) investigate the feasibility of using angiography of the carotid arteries in the guttural pouch region and assess transarterial coil (TAC) placement into the internal carotid artery (ICA). Methods: Experimental study. Methods: Healthy Standardbred horses (n = 6), aged 5-8 years. Methods: Six horses had ultrasound-guided percutaneous CCA catheterization and angiography under general anesthesia. Catheterization sites were ultrasonographically evaluated pos...
Kondampati KD, Saini SPS, Sidhu PK, Anand A, Kumar D, Beesam S, Bedi JS, Kaur R, Bhardwaj R.The pharmacokinetics of ampicillin-cloxacillin, given as single intravenously dose of 10 mg.kg-1 (5 mg.kg-1 of ampicillin plus 5 mg.kg-1 of cloxacillin) was examined in clinically presented Indian thoroughbred horses (n = 6) in order to design appropriate dosing strategies. Drug concentrations in plasma were determined by high performance liquid chromatography (HPLC) and pharmacokinetic parameters were derived by non-compartmental analysis using WinNonlin software. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of ampicillin-cloxacillin against qualit...
Mason ME, Voris ND, Ortis HA, Geeding AA, Kaplan RM.To compare larvicidal regimens of fenbendazole and moxidectin for reduction and suppression of cyathostomin fecal egg counts (FEC) in a transient herd of embryo transfer-recipient mares. Methods: Randomized, complete block, clinical trial. Methods: 120 mares from 21 states, residing on 1 farm. Methods: An initial fecal sample was collected from each mare; mares with an FEC ≥ 200 eggs/g were assigned to treatment groups. Eighty-two horses received fenbendazole (10.0 mg/kg [4.5 mg/lb], PO, q 24 h for 5 days) or moxidectin (0.4 mg/kg [0.18 mg/lb], PO, once); FEC data were analyzed 14, 45, and 9...
Schuster RK, Sivakumar S.Although the life cycle of the equid stomach parasite Habronema muscae was disclosed more than 100 years ago, little is known about the effect of the developing nematode larvae in its intermediate host, Musca domestica. In a series of experiments, freshly hatched M. domestica larvae were exposed to H. muscae eggs contained in a faecal sample of a naturally infected horse. In daily intervals, 50 fly larvae were removed and transferred on a parasite-free larval rearing medium where they completed their development. Hatched flies were examined for the presence of Habronema third-stage larvae. In...
Tosi I, Bureau F, Farnir F, Denoix JM, Lekeux P, Art T.Cytosine-phosphate-guanosine (CpG-ODN) has been described as a potent immunostimulatory agent in different species. No study reported the effect of a P-class CpG when administered systemically in healthy horses. The aim of this study was to evaluate the tolerance and the effect of an intramuscularly administered P-class CpG-ODN on hematology and on plasma cytokines (IFN-α, IL-10, TNF-α, IFN-γ) in 8 healthy horses. Intra-muscular CpG-ODN or placebo (PBS) was administered twice at a 7 days-interval. Groups were inversed after 2 months of washout period. A physical examination, complete bloo...
Brown KA, Sayasith K, Bouchard N, Lussier JG, Sirois J.The type 1 form of 17beta-hydroxysteroid dehydrogenase (17betaHSD1) was the first isoform to be identified and is capable of converting estrone to 17beta-estradiol. This study was aimed at characterizing the molecular structure of the equine 17betaHSD1 gene and cDNA, as well as its molecular regulation during human chorionic gonadotropin (hCG)-induced follicular luteinization/ovulation in vivo. The equine 17betaHSD1 gene was cloned from an equine genomic library and shown to have a conserved genomic structure composed of six exons. Its cDNA sequence was also identified and coded for a 308 amin...
Figueiredo MD, Salter CE, Hurley DJ, Moore JN.Lipopolysaccharide-binding protein (LBP) is an acute phase protein that binds the lipid A moiety of lipopolysaccharide (LPS) and transfers LPS monomers to soluble CD14 in plasma or membrane bound CD14 on mononuclear phagocytes. The result of these interactions is activation of the TLR4 receptor complex, and the synthesis and release of inflammatory mediators. Inclusion of LBP in cellular assays increases the sensitivity of cells expressing CD14 to LPS. Therefore, the objectives of this study were to (1) compare differentially treated sera from cattle and horses as sources of LBP activity using...
Joonè CJ, Schulman ML, Fosgate GT, Claes ANJ, Gupta SK, Botha AE, Human A, Bertschinger HJ.Circulating anti-Müllerian hormone concentration (AMH) is positively correlated to the number of small growing follicles in the mare and may reflect ovarian function. Dynamics of AMH during immunocontraception have not previously been investigated. This study aimed to compare serum AMH in mares following treatment with native porcine zona pellucida (pZP), recombinant pZP3 and pZP4 (reZP) or gonadotrophin releasing hormone (GnRH) vaccines, and saline-treated controls. Stored sera collected during two previous studies examining ovarian activity in mares during zona pellucida (ZP) or GnRH immuno...
Ambrisko TD, Lammer V, Schramel JP, Moens YP.A spirometry device equipped with mainstream CO2 flow sensor is not available for large animal anaesthesia. Objective: To measure the resistance of a new large animal spirometry device and assess its agreement with reference methods for volume measurements. Methods: In vitro experiment and crossover study using anaesthetised horses. Methods: A flow partitioning device (FPD) equipped with 4 human CO2 flow sensors was tested. Pressure differences were measured across the whole FPD and across each sensor separately using air flows (range: 90-720 l/min). One sensor was connected to a spirometry ...
Treonze KM, Alves K, Fischer P, Hagmann WK, Hora D, Kulick A, Vakerich K, Smith ND, Lingham RB, Maniar S, Reger TS, Zunic J, Munoz B, Prasit P....The purpose of this study was to characterize the alpha(4)beta(1) receptor (CD49d/CD29, very late antigen-4, VLA-4) on circulating equine leukocytes and to evaluate the intrinsic potency of an alpha(4)beta(1) receptor antagonist (Compound B) in the horse. Ultimately, these studies would allow us to determine the suitability of treating recurrent airway obstruction (RAO; heaves) affected horses by blocking the cellular recruitment of lymphocytes and neutrophils into the lung. The data demonstrates the alpha(4)beta(1) integrin is present on horse lymphocytes and neutrophils (fluorescence-assiste...
Bergh A, Nyman G, Lundeberg T, Drevemo S.Treatment with defocused CO2 laser can have a therapeutic effect on equine injuries, but the mechanisms involved are unclear. A recent study has shown that laser causes an increase in equine superficial tissue temperature, which may result in an increase in blood perfusion and a stimulating effect on tissue regeneration. However, no studies have described the effects on equine tissue perfusion. The aim of the present study was to investigate the effect of defocused CO2 laser on blood perfusion and to correlate it with temperature in skin and underlying muscle in anaesthetized horses. Differenc...
Ouellette AL, Evans RJ, Heath MF.Endotoxaemia is the leading cause of death in horses. Disseminated intravascular coagulation (DIG), stimulated by induced monocyte proteins, is a prominent feature. Monocyte-platelet cellular interactions are central to the vascular dysfunction produced by circulating endotoxin and are implicated in many thrombotic diseases in the horse. This study reports that endotoxin (0.01-10 microg ml(-1)) and blood platelets (2.5 x 10(7) - 1 x 10(8) ml(-1)) are potent inducers of expression and activity of monocyte tissue factor (TF), the primary activator of the blood coagulation protease cascade. The c...
Muñoz E, Castro M, Aguila L, Contreras MJ, Fuentes F, Arias ME, Felmer R.Sperm sexing is a technology that can generate great economic benefits in the animal production sector. Techniques such as sex-sorting promise over 90% accuracy in sperm sexing. However, for the correct standardization of the technique, some laboratory methodologies are required. The present manuscript describes in detail a standardized equine sperm sex-sorting protocol using an absolute qPCR-based methodology. Furthermore, the results of absolute qPCR were implemented and validated by generating equine/bovine heterologous embryos by intracytoplasmic sperm injection (ICSI) of presumably sexed ...
Medica DL, Sukhdeo MV.Infective larvae (L3) of Strongylus vulgaris have limited energy stores for host finding and for infection. For transmission to occur, the larvae must have sufficient energy to (a) migrate onto grass, where they are ingested by their equine host (host finding), and (b) penetrate into the host gut. This study is designed to test the hypothesis that L3 larvae of S. vulgaris partition their energy stores between locomotory activity (used in host finding) and infection activity (penetration). Chronic locomotory activity was stimulated by incubating S. vulgaris L3 larvae at a constant temperature (...
Lohmann KL, Bahr A, Cohen ND, Boothe DM, Roussel AJ.To evaluate the correlation between the half-time of liquid-phase gastric emptying (T50) determined by use of nuclear scintigraphy, using technetiumTc 99m pentetate, and absorption variables of orally administered acetaminophen in horses with experimentally delayed gastric emptying. Methods: 6 mature horses. Methods: Delayed gastric emptying was induced by IV injection of atropine sulfate. Twenty minutes later, acetaminophen and technetium Tc 99m pentetate were administered simultaneously via nasogastric tube. Serial lateral images of the stomach region were obtained, using a gamma camera. Pow...
Martens RJ, Martens JG, Renshaw HW, Hietala SK.The opsonic capacity of serum containing R. equi-specific antibody was compared with antibody-deficient sera using luminol-dependent chemilumenscence (LDCL) and bactericidal assays. These assays incorporated peripheral blood polymorphonuclear neutrophilic leukocytes (PMNL) exposed to R. equi opsonized with neonatal equine pre-colostral serum (control) or serum from foals with R. equi infections (principal). All sera were complement inactivated at 56 degrees C for 30 min. Bacteria were obtained from the lung of a foal with R. equi pneumonia. Neutrophils were obtained from one adult horse for LD...
Minuto J, Bedenice D, Ceresia M, Zaghloul I, Böhlke M, Mazan MR.Nebulized lidocaine appears promising as a novel corticosteroid-sparing therapeutic for equine asthma, but its safety and pharmacokinetic behavior have yet to be confirmed. Unassigned: To describe the effect of nebulized lidocaine on upper airway sensitivity, lung mechanics, and lower respiratory cellular response of healthy horses, as well as delivery of lidocaine to lower airways, and its subsequent absorption, clearance, and duration of detectability. Unassigned: Six healthy university- and client-owned horses with normal physical examination and serum amyloid A, and no history of respirato...
Mück WM, Henion JD.The performance of microbore high-performance liquid chromatography and capillary zone electrophoresis, both equipped with on-line tandem mass spectrometric detection capability, was evaluated critically for the determination of endogenous amounts of leucine enkephalin and methionine enkephalin in equine cerebrospinal fluid. Using an identical sample clean-up and enrichment procedure, capillary zone electrophoresis-mass spectrometry is limited in its concentration detection capacity owing to its much smaller injection volume. Leucine enkephalin was identified in post-mortem equine cerebrospina...
Paweska JT, Volkmann DH, Barnard BJ, Chirnside ED.Two in a group of five naturally seropositive donkey stallions were found to shed equine arteritis virus (EAV) in their semen as demonstrated by virus isolation. Direct intramuscular inoculation of sonicated semen from one virus-shedding stallion (S3) caused clinical disease in two donkeys from which virus was recovered and in which seroconversion was detected. Sexual transmission was confirmed in two mares mated to S3 when after a febrile response during which EAV was isolated from huffy coats and nasal and ocular exudates, both mares were found to have seroconverted. In-contact transmission ...
Acland HM, Allen PZ, Kenney RM.After contagious equine metritis bacteria were inoculated into the uterus of mares, genital tract tissues were examined for presence of the organism by bacteriologic cultural technique and an indirect immunofluorescent staining technique. Up to 14 days after mares were inoculated, the organism was frequently in the lumen of the uterus and in the cervix and, less frequently, in the vagina, vestibule, clitoral fossa, clitoral sinus, and uterine tubes. After 21 to 116 days, the organism was occasionally found on the ovarian surface, in the uterine tubes, uterus, cervix, and vagina and more freque...
