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.
Scully CM, Lee RL, Pielstick L, Medlock J, Patton KM, Collins GH, Kutzler MA.Free-roaming horse (Equus caballus) management is a complex issue incorporating social, economic, emotional, political, and environmental factors. Currently, few proven field techniques exist for managing free-roaming horse population growth, which can reach 20-25% annually. Although there are several strategies available for sterilizing mares when managing free-roaming horse populations, surgical vasectomy is the only method used in the field for stallions. Some managers believe that surgically vasectomizing dominant stallions would have significant effects on reducing horse populations. Howe...
Robinson KA, Manning ST.Acupuncture is used without strong scientific evidence to treat many diseases of the horse, including palmar heel pain. Research is needed to provide evidence for the application of these treatments. Within the confines of our study, acupuncture did not reliably modulate palmar heel pain in horses. Efficacité d’un traitement d’acupuncture à formule simple pour les chevaux souffrant de douleur du talon palmaire. L’acupuncture est utilisée, en l’absence de solides preuves scientifiques, pour traiter plusieurs affections des chevaux, y compris la douleur du talon palmaire. De la recher...
Dudhia J, Becerra P, Valdés MA, Neves F, Hartman NG, Smith RK.Recent advances in the application of bone marrow mesenchymal stem cells (BMMSC) for the treatment of tendon and ligament injuries in the horse suggest improved outcome measures in both experimental and clinical studies. Although the BMMSC are implanted into the tendon lesion in large numbers (usually 10 - 20 million cells), only a relatively small number survive (<10%) although these can persist for up to 5 months after implantation. This appears to be a common observation in other species where BMMSC have been implanted into other tissues and it is important to understand when this loss o...
Best LJ, Hendrix DV, Ward DA.To evaluate the tear film osmolality and electrolyte composition in healthy horses. Methods: 15 healthy adult horses. Methods: Each horse was manually restrained, and an ophthalmic examination, which included slit-lamp biomicroscopy, indirect ophthalmoscopy, and a Schirmer tear test, was performed. Tear samples were collected from both eyes with microcapillary tubes 3 times at 5-minute intervals. The tear samples for each horse were pooled, and the osmolality and electrolyte concentrations were measured. The mean (SD) was calculated for each variable to establish preliminary guidelines for tea...
Perrin R, Diguet AC, Cantet P, Bailly C, Brogniez L, Dugdale A, Nisolle JF, Vandeweerd JM.Synovitis of the navicular bursa is common in performance horses. The objective of this study was to describe an ultrasound-guided technique to inject a distended navicular bursa and to evaluate its feasibility for use by a clinician not trained in the technique. Twenty distal limbs of horses of various breeds and sizes were used. To produce synovial distension, the navicular bursa of each limb was injected with contrast medium using a lateral approach and radiography was performed to confirm that the contrast medium was distending the bursa. The digit was positioned with the distal interphala...
Merkl M, Ertl R, Handschuh S, Aurich C, Schäfer-Somi S.In the present study, we assessed the presence of the ATP-binding-cassette (ABC) transporter molecules ABCA1 in spermatozoa of adult stallions and in testicular and epididymal tissue of prepubertal and adult stallions. For this purpose, semen samples from six fertile Shetland pony stallions aged 4 to 19 years were collected. Semen was collected from each stallion on three consecutive days. Ejaculates were analyzed immediately after collection, and only ejaculates meeting minimal requirements for fertile stallions were further evaluated. ABCA1 immunosignal was localized after staining of semen ...
Aristizabal FA, Nieto JE, Guedes AG, Dechant JE, Yamout S, Morales B, Snyder J.Regional limb perfusion (RLP) in horses has proven to be a simple and effective technique for the treatment of synovial and musculoskeletal infections in the distal portion of the limbs. The ideal tourniquet time needed to achieve therapeutic synovial concentrations remains unknown. The pharmacokinetic effects of general anesthesia (GA) versus standing sedation (SS) RLP on synovial amikacin concentrations are not completely understood. This study investigated the pharmacokinetic effects of RLP under general anesthesia (GA) versus standing sedation (SS) on synovial amikacin concentration follow...
Pavulraj S, Bera BC, Joshi A, Anand T, Virmani M, Vaid RK, Shanmugasundaram K, Gulati BR, Rajukumar K, Singh R, Misri J, Singh RK, Tripathi BN....Equine influenza viruses (EIV)-H3N8 continue to circulate in equine population throughout the world. They evolve by the process of antigenic drift that leads to substantial change in the antigenicity of the virus, thereby necessitating substitution of virus strain in the vaccines. This requires frequent testing of the new vaccines in the in vivo system; however, lack of an appropriate laboratory animal challenge model for testing protective efficacy of equine influenza vaccine candidates hinders the screening of new vaccines and other therapeutic approaches. In the present investigation, BALB/...
Bavin EP, Smith O, Baird AE, Smith LC, Guest DJ.Tendon injuries occur commonly in horses and their repair through scar tissue formation predisposes horses to a high rate of re-injury. Pluripotent stem cells may provide a cell replacement therapy to improve tendon tissue regeneration and lower the frequency of re-injury. We have previously demonstrated that equine embryonic stem cells (ESCs) differentiate into the tendon cell lineage upon injection into the damaged horse tendon and can differentiate into functional tendon cells in vitro to generate artificial tendons. Induced pluripotent stem cells (iPSCs) have now been derived from horses b...
Reilas T, Rivera Del Alamo MM, Liepina E, Yeste M, Katila T.Cervical patency is considered to be important for uterine drainage after mating or artificial insemination (AI), and failure to relax or premature tightening of the cervix can lead to persistent endometritis. This study investigated the hypothesis that cervical occlusion after AI increases accumulation of fluid, polymorphonuclear leukocytes (PMNs), and cytokines in the uterine lumen. Endometrial swabs were obtained from 29 normal cyclic mares during the first, third, and fifth estrus and biopsies during the first and fifth estrus. All mares were inseminated during the second and fourth estrus...
Gao W, Chan Y, You M, Lacap-Bugler DC, Leung WK, Watt RM.This study explored the range of bacterial taxa present within healthy subgingival (below the gum-line) niches in the horse oral cavity using 16S rRNA gene amplicon pyrosequencing. Pooled subgingival plaque samples were collected from approximately 200 sulcus sites from two horses (EQ1, EQ2) for analysis. A total of 14,260 quality-filtered pyrosequencing reads were obtained, which were assigned to 3875 operational taxonomic units (OTUs; 99% identity cut-off); 1907 OTUs for EQ1 and 2156 OTUs for EQ2. Diverse taxa from 12 phyla were identified, including Actinobacteria (3.17%), Bacteroidetes (25...
Kim JT, Jung HJ, Song H, Yoon MJ.Acrosin Binding Protein (ACRBP) is specifically localized in the acrosome of germ cells of several species, including mice, pigs, guinea pigs, and humans. The main objective of this study was to investigate ACRBP patterns in the germ cells of stallions at different reproductive stages and seminiferous tubule stages using Western blot, immunohistochemistry, and immunocytochemistry techniques. The stallion reproductive stages were classified as follows: pre-pubertal and post-pubertal stages based on the presence/absence of lumen opening in the seminiferous tubules and full spermatogenesis. The p...
Claes A, Ball BA, Troedsson MH, Curry TE, Squires EL, Scoggin KE.The wide variation in circulating anti-Müllerian hormone (AMH) concentrations between mares is attributed to differences in antral follicle count (AFC) which may reflect follicular function. There are few data regarding variations in AFC and associated regulatory factors for AMH in the equine follicle during follicular development. Objective: To examine molecular and hormonal differences in the equine follicle in relation to variations in AFC and circulating AMH concentrations during follicular development and to identify genes co-expressed with AMH in the equine follicle. Methods: Observatio...
de Laat MA, McGree JM, Sillence MN.Compared with some other species, insulin dysregulation in equids is poorly understood. However, hyperinsulinemia causes laminitis, a significant and often lethal disease affecting the pedal bone/hoof wall attachment site. Until recently, hyperinsulinemia has been considered a counterregulatory response to insulin resistance (IR), but there is growing evidence to support a gastrointestinal etiology. Incretin hormones released from the proximal intestine, glucagon-like peptide-1 (GLP-1) and glucose-dependent insulinotropic peptide, augment insulin secretion in several species but require invest...
Perez B, Henriquez C, Sarmiento J, Morales N, Folch H, Galesio JS, Uberti B, Morán G.Neutrophilic asthma is an important disease subgroup, including patients with severe phenotypes and erratic responses to standard treatments. Tamoxifen (TX), a selective estrogen receptor modulator (SERM) used as treatment of human breast cancer, has been shown to induce early apoptosis of equine blood and bronchoalveolar lavage fluid (BALF) neutrophils in vitro. Equine recurrent airway obstruction (RAO) is a naturally occurring neutrophilic condition, closely related with human asthma. Our purpose was to investigate the therapeutic potential of tamoxifen in horses with neutrophilic lung infla...
Schellenbacher C, Shafti-Keramat S, Huber B, Fink D, Brandt S, Kirnbauer R.The consistent and specific presence of Equus caballus papillomavirus type 2 (EcPV2) DNA and mRNA in equine genital squamous cell carcinoma (gSCC) is suggestive of an etiological role in tumor development. To further validate this concept, EcPV2-neutralizing serum antibody titers were determined by an EcPV2 pseudovirion (PsV) neutralization assay. Furthermore, an EcPV2 L1 virus-like particle (VLP)-based vaccine was generated and its prophylactic efficacy evaluated in vivo. All 6/6 gSCC-affected, but only 3/20 tumor-free age-matched animals revealed EcPV2-neutralizing serum antibody titers by P...
Bertuglia A, Lacourt M, Girard C, Beauchamp G, Richard H, Laverty S.The role of osteoclasts in osteochondral degeneration in osteoarthritis (OA) has rarely been investigated in spontaneous disease or animal models of OA. Objective: The objectives of the current study were to investigate osteoclast density and location in post-traumatic OA (PTOA) and control specimens from racehorses. Methods: Cores were harvested from a site in the equine third carpal bone, that undergoes repetitive, high intensity loading. Histological and immunohistochemical (Cathepsin K and Receptor-activator of Nuclear Factor kappa-β ligand (RANKL)) stained sections were scored (global an...
Ortved KF, Nixon AJ.Damage to the articular cartilage surface is common in the equine athlete and, due to the poor intrinsic healing capabilities of cartilage, can lead to osteoarthritis (OA). Joint disease and OA are the leading cause of retirement in equine athletes and currently there are no effective treatments to stop the progression of OA. Several different cell-based strategies have been investigated to bolster the weak regenerative response of chondrocytes. Such techniques aim to restore the articular surface and prevent further joint degradation. Cell-based cartilage repair strategies include enhancement...
Vandenberghe A, Broeckx SY, Beerts C, Seys B, Zimmerman M, Verweire I, Suls M, Spaas JH.Suspensory ligament injuries are a common injury in sport horses, especially in competing dressage horses. Because of the poor healing of chronic recalcitrant tendon injuries, this represents a major problem in the rehabilitation of sport horses and often compromises the return to the initial performance level. Stem cells are considered as a novel treatment for different pathologies in horses and humans. Autologous mesenchymal stem cells (MSCs) are well known for their use in the treatment of tendinopathies; however, recent studies report a safe use of allogeneic MSCs for different orthopedic ...
Olsen E, Pedersen TL, Robinson R, Haubro Andersen P.Arterial blood pressure (BP) is a relevant clinical parameter that can be measured in standing conscious horses to assess tissue perfusion or pain. However, there are no validated oscillometric noninvasive blood pressure (NIBP) devices for use in horses. Methods: Seven healthy horses from a teaching and research herd. Objective: To evaluate the accuracy and precision of systolic arterial pressure (SAP), diastolic arterial pressure (DAP), and mean arterial pressure (MAP) in conscious horses obtained with an oscillometric NIBP device when compared to invasively measured arterial BP. Methods: An ...
Reinemeyer CR, Prado JC, Nielsen MK.Despite widespread acknowledgement of cyathostomin resistance to adult icidal dosages of benzimidazole (BZD) anthelmintics, many strongyle control programs continue to feature regularly scheduled larvicidal treatment with fenbendazole (FBZ). However, no studies have been conducted to evaluate the efficacy of larvicidal regimens against encysted cyathostomins in a BZD-resistant (BZD-R) population. A masked, randomized, controlled clinical study was conducted with 18 juvenile horses harboring populations of cyathostomins that were considered BZD-R on the basis of fecal egg count reduction (FECR)...
Hepworth-Warren KL, Wong DM, Hay-Kraus BL, Wang C, Sun Y.This study compared the effects of IV administration of isotonic fluid therapy and colloidal fluid therapy in healthy neonatal foals. Fifteen healthy neonatal foals were used in a randomized blinded prospective clinical study. Foals were randomly assigned to receive a bolus of 20 mL/kg of tetrastarch (TES) or balanced crystalloid solution. Vital parameters, colloid osmotic pressure (COP), and various clinicopathologic variables were assessed prior to infusion and at various time points up to 120 h after infusion. The treatment group (TES) had a significant increase in both COP and percentage i...
Jensen RB, Kyrstein TD, Junghans P, Tauson AH.Energy expenditure (EE) can be estimated based on respiratory gas exchange measurements, traditionally done in respiration chambers by indirect calorimetry (IC). However, the (13)C-bicarbonate technique ((13)C-BT) might be an alternative minimal invasive method for estimation of CO(2) production and EE in the field. In this study, four Shetland ponies were used to explore the effect of feeding on CO(2) production and EE measured simultaneously by IC and (13)C-BT. The ponies were individually housed in respiration chambers and received either a single oral or intravenous (IV) bolus dose of (13)...
González-Fernández L, Macedo S, Lopes JS, Rocha A, Macías-García B.Equine in vitro fertilization (IVF) is still inconsistent. In the present work, we studied how modified Whitten's (MW) medium and Tissue Culture Medium 199 (TCM) added with Foetal Bovine Serum (FBS; 10% v/v) or Bovine Serum Albumin (BSA; 7 mg/ml) affected equine gametes to subsequently run IVF trials. Compact (Cp) and expanded (Ex) cumuli equine oocytes were matured and placed in TCM or MW supplemented with BSA or FBS for 18-20 h (no sperm added). In Ex oocytes, TCM-199 added with FBS or BSA resulted in higher metaphase II (MII) rates (75.7% and 62.7%, respectively) than MW added with BSA (54%...
Kim JY, Jung HJ, Yoon MJ.Expression of the protein DDX4/MVH, or VASA, has been reported in germ cells of several species. The main objectives of this study were to (i) investigate VASA expression patterns in testicular cells of stallions at two different reproductive stages (pre-pubertal and post-pubertal) and (ii) evaluate the use of VASA antibody as a molecular marker for single germ cells from stallions. Testicular tissues were obtained from stallions and categorized as pre-pubertal and post-pubertal based on the formation of lumen and status of spermatogenesis on the cross section of seminiferous tubules. The resu...
Tomlinson JE, Taberner E, Boston RC, Owens SD, Nolen-Walston RD.There is a markedly reduced half-life of transfused RBCs when donor and recipient cats or humans are cross-match incompatible. Only 10-20% of horses have naturally occurring alloantibodies. Therefore, cross-match testing before blood transfusion is not always performed. Objective: Cross-match incompatibility predicts shortened RBC survival time as compared to that of compatible or autologous blood. Methods: Twenty healthy adult horses. Methods: Prospective trial. Blood type, anti-RBC antibody screen (before and 1 month after transfusion) and major and minor cross-match determined 10 donor-reci...
Cheetham J, Perkins JD, Jarvis JC, Cercone M, Maw M, Hermanson JW, Mitchell LM, Piercy RJ, Ducharme NG.Bilateral vocal fold paralysis (BVCP) is a life-threatening condition that follows injury to the Recurrent Laryngeal nerve (RLn) and denervation of the intrinsic laryngeal musculature. Functional electrical stimulation (FES) enables restoration and control of a wide variety of motor functions impaired by lower motor neuron lesions. Here we evaluate the effects of FES on the sole arytenoid abductor, the posterior cricoarytenoid (PCA) muscle in a large animal model of RLn injury. Ten horses were instrumented with two quadripolar intramuscular electrodes in the left PCA muscle. Following a 12-wee...
Bonelli F, Meucci V, Divers TJ, Jose-Cunilleras E, Corazza M, Tognetti R, Guidi G, Intorre L, Sgorbini M.The diseases most frequent associated with SIRS in adult horses are those involving the gastrointestinal tract. An early diagnosis should be the goal in the management of horses with SIRS. Objective: The objective of this study was to evaluate the plasma procalcitonin (PCT) concentration in healthy and SIRS horses to assess differences between the two groups. Methods: Seventy-eight horses (30 healthy and 48 SIRS). Methods: Prospective in vivo multicentric study. Horses were classified as SIRS if at least 2 of the following criteria were met: abnormal leukocyte count or distribution, hypertherm...
Sole A, Nieto JE, Aristizabal FA, Snyder JR.Emptying the vasculature with an Esmarch bandage before i.v. regional anaesthesia is commonly performed in human patients to prevent leakage of the solution under the tourniquet but there is no evidence for its efficacy in horses for antimicrobial i.v. regional limb perfusion (IV-RLP). Objective: To determine the effect on synovial fluid concentration of amikacin of emptying the vasculature before performing IV-RLP. Methods: Crossover experiment. Methods: Eight clinically healthy horses underwent 2 IV-RLP with amikacin in a randomised, crossover design. Horses received an IV-RLP with amikacin ...
Wilmink JM, Ladefoged S, Jongbloets A, Vernooij JCM.The effect of dressings saturated with either a standardized suspension of probiotic bacteria or saline on healing of traumatic distal limb wounds in horses was evaluated for 24 days, and the systemic inflammatory effect was assessed. The wounds were divided in two groups based on the phase of healing: wounds with an incomplete (ICGB) or a complete granulation bed (CGB). The wound area was expressed as percentage of the wound area at day 0 and defined as relative wound area. The mean relative wound area decreased faster in probiotic than saline treated wounds. The difference was most obvious i...
Nourian AR, Asplin KE, McGowan CM, Sillence MN, Pollitt CC.Anatomical changes in the hoof lamellar tissue induced by prolonged hyperinsulinaemia have not been described previously. Analysis of the induced lesions may promote understanding of hyperinsulinaemic laminitis pathogenesis and produce clinical benefit. Objective: To use light and transmission electron microscopy (TEM) to document hoof lamellar lesions in ponies clinically lame after prolonged hyperinsulinaemia. Methods: Nine clinically normal, mature ponies were allocated randomly to either a treatment group (n = 5) or control group (n = 4). The treatment group received insulin via a modified...
Chiocchetti R, Bombardi C, Mongardi-Fantaguzzi C, Venturelli E, Russo D, Spadari A, Montoneri C, Romagnoli N, Grandis A.This paper describes the morphology and distribution of the enteric nervous system (ENS) cells and fibres immunoreactive for choline acetyltransferase (ChAT), neuronal nitric oxide synthase (nNOS), substance P (SP), calcitonin gene-related peptide (CGRP), NF200kDa (NF200), and S100 protein. The percentages of subclasses of enteric neurons in the total neuronal population were investigated by the use of anti-PGP 9.5 or anti-NSE antibodies. ChAT-IR myenteric plexus (MP) and submucosal plexus (SMP) neurons were 66+/-7% and 74+/-15%, respectively, whereas those cells expressing nNOS-IR were 38+/-7...
Freeman DA, Woods GL, Vanderwall DK, Weber JA.The hypothesis that equine embryos initiate oviductal transport in mares was tested by placing day 6 uterine embryos in the oviducts of day 2 (n = 10) or day 5 (n = 10) recipient mares and attempting to collect the embryos from the uterus 48 h later. To determine whether the surgical transfer procedure initiated oviductal transport, medium alone was placed in the oviducts of day 2 (n = 10) inseminated mares (sham transfer), and uterine embryo collections were attempted 48 h later. Embryos were transported through the oviduct of day 2 recipients by day 4 (instead of day 5 to 6) in six of ten ma...
Moens Y, Lagerweij E, Gootjes P, Poortman J.To study effects of intermittent positive-pressure ventilation (IPPV) with large tidal volumes and addition of positive end-expiratory pressure (PEEP) on maldistribution of ventilation in anesthetized horses positioned in lateral recumbency. Methods: 6 healthy adult horses. Methods: Anesthesia was induced by i.v. infusion of thiopental sodium and guiafenesin and was maintained with supplemental doses of thiopental and i.v. infusion of chloral hydrate. Functional separation of the lungs was achieved, using a tube-in-tube intubation technique. Intermittent positive-pressure ventilation of both l...
Maloney SE, Khan FA, Chenier TS, Diel de Amorim M, Anthony Hayes M, Scholtz EL.Proteomic analysis of mare uterine flush fluid provides a minimally invasive technique for studying protein changes associated with the oestrous cycle. The aim of this study was to identify differentially abundant proteins in the uterine flush fluid of mares in oestrus and dioestrus. In this study, uterine flush fluid samples were collected from eight reproductively healthy mares in either oestrus (n = 5) or dioestrus (n = 3). Proteomic analysis was performed using liquid chromatography-tandem mass spectrometry. Of 172 proteins identified, six proteins (immunoglobulin lambda-like polypepti...
Segura D, Monreal L, Pérez-Pujol S, Pino M, Ordinas A, Brugués R, White JG, Escolar G.We studied equine platelet function and activation using ultrastructural examination, flow cytometry, and perfusion. The main aim of the study was to evaluate hemostatic mechanisms in horses using these techniques. Ultrastructural observations were done on resting and activated platelets. Flow cytometry was used to evaluate binding of antibodies to major platelet glycoproteins (GPIIb-IIIa, GPIV, and GPIb) and activation-dependent antigens (P-selectin and lysosomal integral membrane protein [LIMP]). Perfusion techniques were used to evaluate the interaction between platelets and damaged subendo...
Clegg PD, Carter SD.A study was performed to identify the activation status of the gelatinase MMPs, MMP-2 and -9, in both normal and diseased equine articular tissues. In addition, the production and activation status of equine MMP-2 and -9 by equine articular cells and tissues in response to increasing IL-1beta concentrations was assessed. The study was performed to test the hypothesis that activation of MMPs is a fundamental step in the pathogenesis of joint diseases; and that this activation is mediated by the cytokine IL-1. Using purified equine MMP-2 and -9, the molecular weights of the zymogen and activated...
Schauvliege S, Gasthuys F.Despite the use of balanced anesthesia and fluids, drugs for cardiovascular support are often needed in anesthetized horses. Antimuscarinics can be used to treat bradycardia unrelated to hypertension. Vasopressors can be useful when hypotension is caused by vasodilation and/or when the effect of fluids and inotropes is insufficient. In most cases, however, inotropes, including sympathomimetics, calcium salts, and phosphodiesterase inhibitors, are preferred. Of the β-sympathomimetics, dobutamine remains the agent of choice. Calcium salts are mainly useful in hypocalcemic patients. Phosphodiest...
Contino EK, King MR, Valdés-Martínez A, McIlwraith CW.Hindlimb proximal suspensory desmopathy is a common injury of sport horses but diagnosis can be difficult because diagnostic analgesia of the region lacks specificity. Perineural analgesia of the deep branch of the lateral plantar nerve (DBLPN) has been proposed as a more specific method of isolating pain of the proximal aspect of the suspensory ligament but the technique has not been evaluated in vivo. Objective: To determine the extent of diffusion of contrast medium and mepivacaine following DBLPN analgesia using a single-needle injection technique and to determine if there is inadvertent i...
Tallmadge RL, Such KA, Miller KC, Matychak MB, Felippe MJ.Common variable immunodeficiency (CVID) is a heterogeneous disorder of B cell differentiation or function with inadequate antibody production. Our laboratory studies a natural form of CVID in horses characterized by late-onset B cell lymphopenia due to impaired B cell production in the bone marrow. This study was undertaken to assess the status of B cell differentiation in the bone marrow of CVID-affected horses by measuring the expression of genes essential for early B cell commitment and development. Standard RT-PCR revealed that most of the transcription factors and key signaling molecules ...
Grimsrud KN, Ait-Oudhia S, Durbin-Johnson BP, Rocke DM, Mama KR, Rezende ML, Stanley SD, Jusko WJ.The present study characterizes the pharmacokinetic (PK) and pharmacodynamic (PD) relationships of the α2-adrenergic receptor agonists detomidine (DET), medetomidine (MED) and dexmedetomidine (DEX) in parallel groups of horses from in vivo data after single bolus doses. Head height (HH), heart rate (HR), and blood glucose concentrations were measured over 6 h. Compartmental PK and minimal physiologically based PK (mPBPK) models were applied and incorporated into basic and extended indirect response models (IRM). Population PK/PD analysis was conducted using the Monolix software implementing t...
Gilger BC, Stoppini R, Wilkie DA, Clode AB, Pinto NH, Hempstead J, Gerding J, Salmon JH.To describe the use of episcleral silicone matrix cyclosporine (ESMC) drug delivery devices in horses with immune-mediated keratitis (IMMK) with evaluation of tolerability and efficacy in long-term control of inflammation. Methods: Retrospective study. ESMC implants (1.2 cm length, 30% wt/wt cyclosporine (CsA) in silicone; with approximately 2 μg/day steady-state release for at least 400 days) were used. Results: Nineteen horses (20 eyes) received two or more ESMC implants for superficial stromal (n = 9), midstromal (n = 3), or endothelial (n = 5) IMMK. Three additional horses received two or...
Larsson P, Persson E, Tydén E, Tjälve H.Horses may be exposed to aflatoxin B(1) (AFB(1)) via inhalation of mouldy dust, leading to high exposure of olfactory and respiratory tissues. In the present study the metabolic activation of AFB(1) was examined in olfactory and respiratory tissues in horse. The results showed covalent binding of AFB(1)-metabolites in sustentacular cells and cells of Bowman's glands in the olfactory mucosa, in some cells of the surface epithelium of nasal respiratory, tracheal, bronchial and bronchiolar mucosa and in some glands in these areas. Immunohistochemistry revealed that cells expressing proteins react...
Eyre P.Systemic anaphylaxis was induced in seven groups of ponies. Systemic hypotension, pulmonary hypotension, and apnea were observed in the control group. Suppression of anaphylaxis was achieved most efficiently with sodium meclofenamate followed by acetylsalicylic acid and diethylcarboamazine. Tripelennamine and methysergide reduced anaphylaxis minimally and burimamide not at all. The findings suggest that histamine and serotonin are of relatively low significance in equine anaphylaxis whereas kinins, prostaglandins and slow reacting substance may be more important.
Carvalho R, Oliveira AM, Souza AM, Passos LM, Martins AS.In this study, an improved polymerase chain reaction (PCR) was used for detection of DNA of latent EHV-1 strains from several sources. Three pairs of oligonucleotide primers spanning fragments of 333 bp, 226 bp and 268 bp of the thymidine kinase (tk) gene, and one primer pair spanning 225 bp of the glycoprotein C (gC) gene were used in specific amplifications. Primers for EHV-4 PCR were also designed. Restriction digests with TaqI confirmed the identity of tk PCR fragments from EHV-1. The sensitivity to detect PCR products was further improved by visualisation in silver-stained acrylamide gels...
Bauquier JR, Forbes G, Nath L, Tudor E, Bailey SR.Acute gastrointestinal disease occurs commonly in horses. Novel biomarkers might improve the understanding of SIRS and aid diagnosis and determination of prognosis. Objective: Increased plasma concentrations of the biomarkers HMGB-1 and nucleosomes are associated with severity of gastrointestinal lesions in horses; concentrations of these biomarkers will be greater in horses with lesions more likely to cause SIRS; and will provide additional information compared with standard biomarkers fibrinogen and SAA. Methods: Thirty horses with gastrointestinal disease, 22 healthy horses. Methods: Prospe...
Moore RM, Bertone AL, Muir WW, Stromberg PC, Beard WL.Effects of low-flow ischemia and reperfusion of the large colon on mucosal architecture were determined in horses. Twenty-four adult horses were randomly allocated to 3 groups: sham-operated (n = 6), 6 hours of ischemia (n = 9), and 3 hours of ischemia and 3 hours of reperfusion (n = 9). Low-flow ischemia was induced in horses of groups 2 and 3 by reducing colonic arterial blood flow to 20% of baseline values. Systemic hemodynamic and metabolic variables were maintained constant and in a normal physiologic range. Full-thickness biopsy specimens were obtained from the left ventral colon for his...
Snow DH, Guy PS.The use of the technique of percutaneous needle biopsy in obtaining skeletal muscle samples in the horse is described. The biochemical, ultrastructural and histochemical investigations that can be carried out on this biopsy specimen are outlined. Analyses performed on the specimen may be used to obtain information on racing potential and state of fitness. These studies on normal horses will provide information for future investigations into the structural and biochemical alterations in muscle disorders in the equine.
Allen PZ, Dalton EJ.Donkey IgGa was isolated in purified form from normal and immune donkey sera by column chromatography on DEAE-cellulose. Isolated donkey IgGa and mixtures of (IgGa+IgGb) were used as antigens to prepare rabbit reagents specific for equine IgGa or IgGb. Antibodies present in sera obtained from a single donkey at various times during the course of hyperimmunization with BSA were isolated by immuno-adsorption. The class or subclass of immunoglobulins present among isolated, donkey anti-BSA antibodies was determined by use of specific rabbit anti-equine immunoglobulin reagents. The homologues of h...
Yuan Z, Philbey AW, Gault EA, Campo MS, Nasir L.Papillomaviruses are normally strictly species-specific and even under experimental conditions do not usually infect any other host than the natural host. The only documented reports of natural papillomavirus cross-species infection are of BPV-1/BPV-2, which can infect horses and induce equine sarcoids. BPV DNA has not been detected in non-sarcoid equine tumours or equine papillomas, but its presence has been reported in some cases of equine dermatitis. In the present study, we show that equine inflammatory skin conditions harbour episomal circular double stranded BPV-1 genomes, with copy numb...
Larenza MP, Peterbauer C, Landoni MF, Levionnois OL, Schatzmann U, Spadavecchia C, Thormann W.To evaluate pharmacokinetics of ketamine and norketamine enantiomers after constant rate infusion (CRI) of a subanesthetic dose of racemic ketamine or S-ketamine in ponies. Methods: Five 6-year-old Shetland pony geldings that weighed between 101 and 152 kg. Methods: In a crossover study, each pony received a CRI of racemic ketamine (loading dose, 0.6 mg/kg; CRI, 0.02 mg/kg/min) and S-ketamine (loading dose, 0.3 mg/kg; CRI, 0.01 mg/kg/min), with a 1-month interval between treatments. Arterial blood samples were collected before and at 5, 15, 30, 45, and 60 minutes during drug administration and...
Brown P.Synthetic mesh products have been used to repair abdominal wall defects (eg, hernias) for many years. Biological mesh products are now available as an option when synthetic mesh products are not appropriate. To correctly prepare biological tissue grafts for use in the OR, perioperative nurses must understand the types of grafts available. Biological tissue grafts may be harvested from human, porcine, bovine, or equine hosts and from skin, pericardium, or small intestine submucosa.
Hosaka Y, Teraoka H, Yamamoto E, Ueda H, Takehana K.The aim of the present study was to clarify the presence and determine the role of apoptosis in the degenerative process of the superficial digital flexor tendon (SDFT) in the horse. Samples were obtained from normal and inflamed SDFTs of horses. To detect apoptosis and to identify apoptotic cells, the samples were subjected to immunohistochemical labelling and Western blot analysis. Although a large number of cells in degenerate areas showed positive reactions with caspase-3 and single stranded DNA antibodies, cells in normal tendon samples showed very weak reactions. Excessive apoptosis was ...
Erber M, Geisel O.The prevalence of Sarcocystis spp. in horses was investigated in a survey at the Munich abattoir during 1978/79. Muscle specimens (oesophagus, diaphragm, sublingual muscle, myocardium) were examined using tryptic digestion. Out of 200 horses 31 (15.5%) were found to be carriers of sarcocysts. No parasites were found in the myocardium. In three animals sarcocysts could be isolated and differentiated in fresh preparations. Cysts with 5 to 11 microns by less than 0.5 microns hairlike, unstable protrusions were classified as Sarcocystis equicanis, whereas those with 2.5 to 4.5 microns by 0.8 to 1....
Kheder MH, Sillence MN, Bryant LM, de Laat MA.Metabolic disease is a significant problem that causes a range of species-specific comorbidities. Recently, a better understanding of glucose-dependent insulinotropic polypeptide (GIP) biology has led to the suggestion that inhibiting its action may attenuate obesity in several species. In horses, antagonism of GIP may also reduce hyperinsulinemia, which leads to insulin-associated laminitis, a painful comorbidity unique to this species. However, little is known about GIP in horses. The aims of this study were to examine the tissue distribution of equine GIP receptors (eGIPR), to determine whe...
Blähser S.In the thyroid glands of the horse, pig, deer, mole, and rat, C-cells could be demonstrated by means of the immunocytochemical PAP-technique using rabbit antisera against human calcitonin. Only in ruminants, the cross-reaction between the intracellularly stored antigen and the antibodies used appeared to be incomplete.
