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.
van Erck E, Votion D, Art T, Lekeux P.Due to technical implementations and lack of sensitivity, pulmonary function tests are seldom used in clinical practice. Impulse oscillometry (IOS) could represent an alternative method. Objective: To define feasibility, methodology and repeatability of IOS, a forced oscillation technique that measures respiratory resistance (Rrs) and reactance (Xrs) from 5 to 35 Hz during spontaneous breathing, in horses. Methods: Using 38 healthy horses, Rrs and Xrs reference values were defined and influence of individual biometrical parameters was investigated. In addition, IOS measurements of 6 horses sho...
Mäkelä OT, Lammi MJ, Uusitalo H, Viitanen M, Hyttinen MM, Jurvelin JS, Vuorio E, Helminen HJ, Tulamo RM.To analyze the effect of radiosynovectomy with holmium-166 ferric hydroxide macroaggregate (166Ho-FHMA) on articular cartilage in 6 adult horses. Methods: Arthritic changes and mechanical properties of articular cartilage were evaluated with arthroscopy and postmortem microscopic analyses. Glycosaminoglycan content was measured by safranin-O staining combined with digital densitometry, uronic acid analyses, and dimethylene blue binding assay. 35S-sulfate labeling and autoradiography were used to localize proteoglycan synthesis and to characterize proteoglycan structures using SDS-agarose gel e...
Blikslager AT.Ischemic injury is one of the most important causes of mortality in equine veterinary medicine. Although treatment of reperfusion injury has been attempted in a number of experimental trials to reduce the level of injury subsequent to an ischemic episode, this research has not resulted in the development of useful clinical treatments. Nevertheless, recent studies assessing intraluminal application of solutions containing antioxidants, nutrients, and vasodilators are promising. Furthermore, focusing on improving mucosal recovery after an ischemic event may provide an alternative method of reduc...
Bentley E, Murphy CJ.A thermal cautery technique was used to treat spontaneous chronic corneal epithelial defects (SCCEDs) in 9 eyes of 8 dogs and 2 eyes of 2 horses. Animals were sedated, and a topical anesthetic was applied. A handheld thermal cautery unit was then used to make multiple, small (< or = 1 mm in diameter), superficial burns throughout the affected area. The cautery unit was applied just until the slightest degree of contraction of the collagen fibrils was observed. After the stromal bed of the defect was treated, a rim of epithelium that extended approximately 1 mm around the denuded stroma was ...
van Ginneken MM, Keizer HA, Wijnberg ID, van Dam KG, Schaart G, de Graaf-Roelfsema E, van der Kolk JH, van Breda E.To investigate whether protein kinase C (PKC) isoforms are expressed in equine skeletal muscle and determine their distribution in various types of fibers by use of immunofluorescence microscopy. Methods: 5 healthy adult Dutch Warmblood horses. Methods: In each horse, 2 biopsy specimens were obtained from the vastus lateralis muscle. Cryosections of equine muscle were stained with PKC isoform (alpha, beta1, beta2, delta, epsilon, or zeta)-specific polyclonal antibodies and examined by use of a fluorescence microscope. Homogenized muscle samples were evaluated via western blot analysis. Results...
Semevolos SA, Nixon AJ, Strassheim ML.To determine the mRNA expression of bone morphogenetic protein (BMP)-6 and -2 and a BMP antagonist (Noggin) in horses with osteochondrosis. Methods: Samples of articular cartilage from affected stifle or shoulder joints of 10 immature horses with naturally acquired osteochondrosis and corresponding joints of 9 clinically normal horses of similar age; additionally, samples of distal femoral growth plate cartilage and distal femoral articular cartilage were obtained from a normal equine fetus. Methods: Cartilage specimens were snap-frozen in liquid nitrogen, and total RNA was isolated. Adjacent ...
Carstanjen B, Hoyle NR, Gabriel A, Hars O, Sandersen C, Amory H, Remy B.To evaluate a human assay for quantification of carboxy-terminal cross-linking telopeptide of type I collagen (CTX-I), assess the influence of age on plasma CTX-I concentration, investigate the relationship between plasma CTX-I and serum osteocalcin concentrations, and determine whether concentrations of plasma CTX-I or serum osteocalcin fluctuate in circadian manner in horses. HORSES: 75 clinically normal horses. Methods: Cross-reactivity between equine serum CTX-I and CTX-I antibodies in an automated electrochemiluminescent sandwich antibody assay (ECLIA) was evaluated via a specificity test...
Brown KA, Boerboom D, Bouchard N, Doré M, Lussier JG, Sirois J.17Beta-hydroxysteroid dehydrogenase type 4 (17betaHSD4) has a unique multidomain structure, with one domain involved in 17beta-estradiol inactivation. The objective of the study was to investigate the regulation of 17betaHSD4 during human chorionic gonadotropin (hCG)-induced ovulation/luteinization. The equine 17betaHSD4 cDNA was cloned and was shown to encode a 735-amino acid protein that is highly conserved (81-87% identity) compared with other mammalian orthologs. RT-PCR/Southern blot analyses were performed to study the regulation of 17betaHSD4 transcripts in equine preovulatory follicles ...
Ginther OJ, Gastal EL, Gastal MO, Beg MA.The role of the insulin-like growth factor (IGF) system in the deviation in growth rates among follicles (follicle selection) was studied in mares using an IGF binding protein (BP) to reduce the follicular-fluid concentrations of IGFs. The future dominant follicle (F1) was treated by intrafollicular injection at the expected beginning of deviation (F1 > or = 20 mm; Day 0). The experimental groups were control (no injection, n = 8), vehicle (injection of vehicle; n = 6), and BP (injection of 250 microg of recombinant human IGFBP-3; n = 6). A sample of follicular fluid was taken from F1 on Da...
Dowdall SM, Proudman CJ, Klei TR, Mair T, Matthews JB.Cyathostomins are the most common parasitic nematodes of horses. Larval stages, which inhabit the intestinal wall, are particularly pathogenic and can cause severe colitis and colic. Despite their clinical importance, diagnostic techniques for the prepatent stages do not exist. A method that could estimate mucosal infection intensity would have a major impact on the control and diagnosis of cyathostominosis. Here, serum IgG(T) responses to two larval antigen complexes of 25 and 20 kDa were quantified in horses with experimental infections, natural infections and in horses that presented with c...
Moure A, Reichmann P, Gamba HR.The application of the dual photon absorptiometry (DPA) technique, using gadolinium-153 as the photon source, to evaluate the bone mineral density (BMD) of the third metacarpal bone of horses is presented. The radiation detector was implemented with a NaI(TI) scintillator coupled to a 14 stage photomultiplier. A modular mechanical system allows the position of the prototype to be adjusted in relation to the animal. A moveable carrier makes it possible to scan the third metacarpal with a velocity adjustable between 1 and 12 mm s(-1), in steps of 1 mm s(-1), for a total distance of 250 mm. The p...
Cordeau ME, Joubert P, Dewachi O, Hamid Q, Lavoie JP.Heaves is a common condition of horses of cold climate that is characterized by small airway inflammation and obstruction following exposure of susceptible horses to moldy hay and straw. It has been shown that helper T lymphocytes (Th) orchestrate the inflammatory response in asthma and in various animal models of allergic lung diseases by the release of Th2-type cytokines. Results of previous studies indicate that a predominant expression of Th2-type response by airway cells may also be present in heaves. To evaluate the temporal mRNA expression of Th1 (IFN-gamma) and Th2 (IL-4, IL-5) type cy...
Cavani F, Fini M, de Terlizzi F, Cadossi M, Ciminelli L, Ortolani S, Cherubini R, De Aloysio D, Giavaresi G, Cadossi R, Canè V.Osteoporosis involves alterations, not only in density, but also in the architectural organisation of the bone; in particular, trabecular orientation, following the skeletal load directions, lends a high degree of stiffness to the whole bone. We investigated the relationship between trabecular orientation, density, stiffness and ultrasound (US) propagation in two orthogonal directions (par. = parallel to, and ort. = orthogonal to the main orientation of the trabeculae) in cylindrical equine bone specimens (thoracic vertebrae) where a preferential orientation is present. A total of 15 cylinders...
Garcia T, Hornof WJ, Insana MF.The strong dependence of tendon echogenicity on insonation angle is explored by analyzing echo spectra. Combining echo spectra with high-resolution images from several modalities reveals that fluid spaces surrounding fascicles and bundles are likely sources of ultrasonic scatter. Mathematical models of tendon structure are proposed to explain how the anisotropic microstructure of tendon gives rise to angle-dependent echogenicity. Echo spectra from spontaneously damaged equine tendon samples were compared with normal equine tendon and found to exhibit a dramatic decrease in anisotropic properti...
Choi YH, Roasa LM, Love CC, Varner DD, Brinsko SP, Hinrichs K.This study was conducted to evaluate in vivo and in vitro development of in vitro-matured equine oocytes fertilized by intracytoplasmic sperm injection. Oocytes were collected from slaughterhouse-derived ovaries, matured in vitro, and injected with frozen-thawed stallion sperm. In vivo development was assessed after transfer of injected oocytes to the oviducts of recipient mares. Mares were killed 7.5-8.5 days after transfer and the uterus and oviducts flushed for embryo recovery. Of 132 injected oocytes transferred, 69 (52%) were recovered; of these, 25 (36%) were blastocysts with a blastocoe...
De Martin I, Theoret CL.To describe immunolocalization of TGF-beta receptors (RI and RII) in normal equine skin and in thoracic or limb wounds, healing normally or with exuberant granulation tissue (EGT). Methods: Group A: six wounds on one metacarpus and one midthoracic area. Group B: six wounds on both metacarpi, one of which was bandaged to stimulate EGT. Immunohistochemistry was used to detect RI and RII expression in wound margins. Methods: Eight horses, randomly assigned to one of two study groups. Methods: Neutralizing polyclonal anti-rabbit RI and RII antibodies were used to detect spatial expression of RI an...
Sutter WW, Hardy J.To describe standing laparoscopic repair of mesoduodenal rent inaccessible by ventral median celiotomy. Methods: Clinical case report. Methods: A 6-year-old Thoroughbred broodmare with a right displacement of the dorsal colon and small intestinal incarceration in a mesoduodenal rent. Methods: Two days after correction of a right dorsal displacement of the ascending colon, small intestinal incarceration, and partial closure of mesoduodenal rent, standing left and right flank laparoscopy was used to explore the abdomen to identify the mesoduodenal defect. The mesenteric rent was repaired from ri...
McClure SR, Van Sickle D, White MR.Extracorporeal shock waves have been used for 30 years to fragment uroliths for nonsurgical treatment for urolithiasis in humans. Applied to bone, shock waves delivered at the appropriate energy and pulse number, can stimulate osteogenesis. In Europe, shock waves are routinely used to treat nonunions in humans despite poor understanding of the mechanism of action. Shock wave therapy has also been used clinically in horses. Preliminary experimental studies indicate that shock wave therapy does not damage soft tissue in the distal aspect of the equine limb and can stimulate osteogenesis througho...
Stepnik MW, Radtke CL, Scollay MC, Oshel PE, Albrecht RM, Santschi EM, Markel MD, Muir P.To examine the fracture failure surfaces from Thoroughbred horses that had sustained a catastrophic condylar fracture. Methods: Bone specimens from the failure surface were obtained from 12 Thoroughbred racehorses with catastrophic injury and 2 non-racing horses with accidental long bone fracture. Methods: Bone specimens from the failure surface of each fracture were incubated with gold microspheres to label microcracks before examination at x50 to x60,000 using scanning electron microscopy. Microcracking at the failure surface was assessed using a visual analog scale. Results: Branching array...
Wyse CA, Love S, Christley RM, Yam PS, Cooper JM, Cumming DR, Preston T.Oxidative stress refers to an imbalance between the production of oxidising free radicals and the antioxidant defenses of the cell, and is associated with many pathogenic processes. Oxidative damage to cellular lipids results in the evolution of pentane and ethane gas, and detection of these hydrocarbons in the exhaled breath can be used to monitor in vivo oxidative stress. The aim of this study was to validate a gas chromatography (GC) method for measurement of breath pentane in the horse. The GC-system developed showed good specificity for discrimination of pentane from other breath hydrocar...
Gonda KC, Wilcke JR, Crisman MV, Ward DL, Robertson JL, Finco DR, Braselton WE.To determine whether pharmacokinetic analysis of data derived from a single i.v. dose of iohexol could be used to predict creatinine clearance and evaluate simplified methods for predicting serum clearance of iohexol with data derived from 2 or 3 blood samples in clinically normal foals. Methods: 10 healthy foals. Methods: Serum disposition of iohexol and exogenous creatinine clearance was determined simultaneously in each foal (5 males and 5 females). A 3-compartment model of iohexol serum disposition was selected via standard methods. Iohexol clearance calculated from the model was compared ...
Kumar S, Gupta AK, Pal Y, Dwivedi SK.The therapeutic efficacy of imidocarb, artesunate, arteether, buparvaquone and arteether+buparvaquone combination was evaluated against Babesia equi of Indian origin in splenectomised donkeys with experimentally induced acute infection. Efficacies of these drugs were tested by administering each drug or drug combination to groups of donkeys (having three donkeys each group). One group of donkey was kept as untreated control for comparing the results. Parasitaemia, haematology (WBC, RBC, PCV, granulocytes and haemoglobin), biochemical parameters (SAST, SALT, alkaline phosphatase, albumin/globul...
Ginther OJ, Gastal EL, Gastal MO, Checura CM, Beg MA.The effect of insulin-like growth factor-I (IGF-I) on the concentrations of follicular fluid factors during follicle deviation and the development of dominance was studied in mares in two experiments. Transvaginal ultrasound guidance was used for intrafollicular injection and subsequent sequential sampling of follicular fluid. Treatment involved a single injection of IGF-I into the second-largest follicle (F2) at the expected beginning of deviation (Hour 0) based on diameter (> or =20 mm) of the largest follicle (F1). Mares in IGF-I groups were given a dose of 500 microg (experiment 1) or 2...
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...
Sieme H, Troedsson MH, Weinrich S, Klug E.Twelve fertile stallions were divided into two groups, either receiving gonadotropin-releasing hormone (GnRH) (n = 6) or Placebo (n = 6). Based on the history of frozen/thawed semen characteristics three stallions within each group were assigned as being "good freezers" [GnRH (+); Placebo (+)] and three stallions were assigned as being "poor freezers" [GnRH (-); Placebo (-)]. The study was performed as a "blinded" investigation and stallions were treated twice daily by an intramuscular injection of 1 ml GnRH (Buserelin), 50 microg) or Placebo. The experiment was divided into three time periods...
Contreiras EC, Lenzi HL, Meirelles MN, Caputo LF, Calado TJ, Villa-Verde DM, Savino W.We characterized herein the microarchitecture of the equine thymus along with post-natal development (6 months-->18 years). Thymuses showed an involutional process, beginning before the puberty and defined by five histological grades, which consider the progressive cortical thymocyte depletion, shrinkage and rearrangement of the epithelial network and increase in extracellular matrix (ECM). A second feature of the equine thymus was the presence of eosinopoiesis, erythropoiesis, mastocytopoiesis and plasmacytogenesis. Additionally, lymphatic vessels, full of lymphocytes, were particularly pr...
Nielsen JV, Berg LC, Thoefnert MB, Thomsen PD.Intra-articular facet joint injection is an established diagnostic procedure in human medicine but there are no reports on its reliability in equine practice. Objective: To investigate the accuracy of ultrasound-guided intra-articular injections of the cervical facet joints and to estimate factors influencing the accuracy. Methods: Sixty injections with blue dye were performed on the facet joints between 2nd and 7th cervical vertebra (C2-C7) on horses subjected to euthanasia for nonorthopaedic reasons. The facet joints were subsequently dissected to verify accuracy of deposition. Results: Seve...
Rumbaugh ML, Burba DJ, Natalini C, Hosgood G, Moore RM.To compare arterial bursting pressure after vessel closure using a vessel-sealing device (LigaSure Atlas Laparoscopic Sealer/Divider Instrument; Valleylab, Boulder, CO), a ligate-and-divide stapling device (LDS), and 2-0 polydioxanone suture. To evaluate the LigaSure Atlas as a method for ligation of the mesenteric vasculature during small intestinal resection in normal horses. Methods: Experimental study. Methods: Part A: jejunal segments from 19 horses. Part B: 6 horses, aged 1 to 18 years, weighing 330 to 509 kg. Methods: Part A: Jejunal segments with mesenteric vessels were collected from ...
Dabareiner RM, White NA, Donaldson L.Ileus and peritoneal adhesions are the most common complications following surgery for small intestinal obstruction. Carolina Rinse (CR) has been shown to decrease reperfusion injury in intestine and other organs. Objective: CR decreases intestinal inflammation and subsequent scarring associated with reperfusion injury. Methods: CR was infused intra-arterially and applied topically just prior to reperfusion in jejunum exposed to experimental ischemia. Vascular permeability, neutrophil accumulation and serosal scarring were compared in treated and untreated intestine. Results: CR maintained a n...
Berg LC, Nielsen JV, Thoefner MB, Thomsen PD.In equine patients, the cause of clinical signs possibly related to the cervical region is often difficult to diagnose. Ultrasonography allows quick and noninvasive visualisation, but reference material of the normal equine neck is needed. Objective: To describe and document the normal ultrasonographic appearance of transverse scans in the cervical region with emphasis on the synovial articular facet joints, cervical vertebrae and paravertebral structures; and further, to provide images of frozen cross-sections for anatomical reference. Methods: A study describing the normal ultrasonographic a...
Davies J, Thomas C, Rizwan M, Gwenin C.The pH drop in the hindgut of the horse is caused by lactic acid-producing bacteria which are abundant when a horse's feeding regime is excessively carbohydrate rich. This drop in pH below six causes hindgut acidosis and may lead to laminitis. Lactic acid-producing bacteria and have been found to produce high amounts of L-lactate and D-lactate, respectively. Early detection of increased levels of these bacteria could allow the horse owner to tailor the horse's diet to avoid hindgut acidosis and subsequent laminitis. Therefore, 16s ribosomal ribonucleic acid (rRNA) sequences were identified a...
Nambo Y, Nagata S, Oikawa M, Yoshihara T, Tsunoda N, Kohsaka T, Taniyama H, Watanabe G, Taya K.Plasma concentrations of immunoreactive (ir)-inhibin were measured in seven pregnant mares from around Day 140 of gestation to Day 2 after parturition using a heterologous bovine-based radioimmunoassay (RIA). Concentrations of luteinizing hormone (LH), follicle-stimulating hormone (FSH), oestradiol-17 beta, progesterone and relaxin were also measured in the same samples. A marked increase in plasma concentrations of ir-inhibin, FSH and LH occurred between Day 220 and Day 300 of gestation but the concentrations of all three hormones returned to baseline by about Day 320 (three weeks before part...
Ethell MT, Hodgson DR, Hills BA.This study was undertaken to determine the hydrophobicity of the luminal surface of the equine stomach and to elucidate the ultrastructure of the lining imparting that property. Gastric and duodenal mucosal samples from 5 horses were collected immediately after euthanasia and subjected to surface contact angle measurement using a goniometer. Gastric mucosal samples from 4 horses and a foal were examined by electron microscopy following a fixation procedure known to preserve phospholipids and oligolamellar structures. Contact angles for the equine gastric glandular mucosal surface (mean +/- s.e...
Hardee MM, Moore JN, Hardee GE.The efficacy of three agents which alter the metabolism of arachidonic acid was investigated in normal, conscious horses. A dose response evaluation was made of flunixin meglumine and phenylbutazone, two cyclo-oxygenase inhibitors, and of a selective thromboxane synthetase inhibitor, UK-38,485. Radioimmunoassay of thromboxane B2 (TxB2) and 6-keto prostaglandin F1 alpha (PGF1 alpha) was used to assess the concentrations of thromboxane A2 (TxA2) and prostacyclin (PGI2) respectively, in serum. Flunixin was the most potent inhibitor of serum TxB2 and 6-keto PGF1 alpha production. UK-38,485 also de...
Albert R, Vásárhelyi G, Bodó G, Kenyeres A, Wolf E, Papp T, Terdik T, Módis L, Felszeghy S.One of the most promising applications for the restoration of small or moderately sized focal articular lesions is mosaicplasty (MP). Although recurrent hemarthrosis is a rare complication after MP, recently, various strategies have been designed to find an effective filling material to prevent postoperative bleeding from the donor site. The porous biodegradable polymer Polyactive (PA; a polyethylene glycol terephthalate - polybutylene terephthalate copolymer) represents a promising solution in this respect. A histological evaluation of the longterm PA-filled donor sites obtained from 10 exper...
Doll CU, Bohner M, Berner D, Buettner K, Horstmeier C, Winter K, Burk J.Low-field magnetic resonance imaging (MRI) has gained increasing importance to monitor equine tendon lesions. Comparing results between studies and cases is hampered, because image analysis approaches vary strongly. This study aimed to improve reliability, comparability and time efficiency of quantitative MRI image analysis. Unassigned: Induced tendon lesions were studied over a 24-week period with 10 follow-up MRI examinations. Signal intensities (SIs) of tendons, tendon lesions, cortical bone and background, as well as lesion cross-sectional areas (CSAs) were measured. Lesion SI standardisat...
Løwenstein H, Markussen B, Weeke B.Sera from 26 patients and 4 normals were examined for specific IgE binding to antigens of extract of horse hair and dandruff by means of CRIE. 22 of the patients were RAST- and intracutaneous-positive to horse extract. 4 more of the patients were RAST-negative to horse allergens, but showed allergies to extract of allergens from sources other than horse. The remaining four sera from controls were RAST-negative to horse and had no history of allergy. Antigens of horse hair and dandruff showed a significantly higher degree of binding to specific IgE in the sera from the first group of patients t...
Weiss DJ, Trent AM, Johnston G.Prothrombotic changes occurring in the prodromal stages of carbohydrate-induced laminitis were investigated. Hemostatic alterations were evaluated by determining platelet counts, platelet survival, activated partial thromboplastin time, one-stage prothrombin time, and monocyte procoagulant activity. Thrombosis of vessels in the hoof wall was evaluated by contrast arteriography and histologic examination. Of 5 horses, 4 became lame between 28 and 52 hours after carbohydrate administration. Mean platelet count in laminitis-affected horses was lower throughout the prodromal stages of laminitis, c...
Moss GE, Estergreen VL, Becker SR, Grant BD.[1,2,6,7-3H]Progesterone was injected into the uterine artery of umbilical vein of 4 pregnant Ponies to determine whether 5 alpha-pregnane-3,20-dione (DHP), 20 alpha-hydroxy-5 alpha-pregnan-3-one (20 alpha-ol), and 3 beta-hydroxy-5 alpha-pregnan-20-one (3 beta-ol) are produced by the placenta, fetus, or mare during late gestation. Plasma samples were collected from indwelling catheters in the uterine artery and vein and the umbilical artery and vein at frequent intervals until 6 h after isotope injection. The plasma samples were extracted with organic solvents and the respective pregnanes were...
Sayasith K, Bouchard N, Doré M, Sirois J.The objectives of the study were to clone the primary structure of the prostaglandin E2 receptor subtype 2 (PTGER2) cDNA and to characterize its regulation in equine follicles during gonadotropin-induced ovulation. Results from DNA isolation indicated that the equine PTGER2 cDNA encodes a predicted 353-amino acid protein, which is highly similar (76-85%) to known mammalian homologues. The regulation of PTGER2 was studied by semi-quantitative RT-PCR/Southern blot using preparations of theca interna and mural granulosa cells isolated from equine follicles 0-39 hr post-treatment with human chorio...
Leeth C, Adkins J, Hay A, Bogers S, Potter A, Witonsky S, Zhu J.Immunological studies in the horse are frequently hampered by lack of environmental control, complicated study design, and ethical concerns when performing high risk studies. The purpose of the current study was to investigate the utility of a xenograft model for studying acute equine immune responses. Immunocompromised non obese diabetic (NOD). sudden combined immunodeficiency (scid).gamma-/- (NSG) mice were engrafted with either equine peripheral blood lymphocytes (PBLs) or equine bone marrow to determine an optimal protocol for equine lymphocyte engraftment. We found that both PBL and bone ...
Schumacher J, Schumacher J, Blanchard T.The endometrial response of mares to repair of third-degree rectovestibular lacerations was evaluated. Endometrial biopsy specimens from 8 mares with third-degree rectovestibular laceration were obtained immediately before surgery and from 9 to 15 days after repair. Presurgical endometrial biopsy specimens were classified as category I for 2 mares; category II, attributable to slight endometritis, for 5 mares; and category III, attributable to moderate-to-severe endometritis, for 1 mare. Within 15 days after rectovestibular repair, all endometrial biopsy specimens were classified as category I...
Wolkowski DD, McCarthy RD, Schoonover MJ, Taylor JD, Eastman TG.Evaluate effects of acellular equine liquid amnion allograft (ELAA) injected into healthy equine joints. Methods: Randomized, blinded, controlled experiment. Methods: Eight healthy adult horses. Methods: One intercarpal joint (ICJ) of each horse was randomly assigned to be injected with 1.5 ml of ELAA (treatment) while the contralateral ICJ was injected with 1.5 ml of 0.9% NaCl (control). Subjective lameness evaluation, force plate analysis, and synovial fluid analysis, including interleukin-1 receptor antagonist (IL-1ra) analysis, were performed before (day 0) and at days 1, 3, 5, and 10. S...
Topper MJ, Prasse KW.To measure coagulation factor VIII:coagulant (F.VIII:C) and C1-esterase inhibitor (C1-INH), hemostasis-associated acute-phase reactant proteins and coagulation factors VII (F.VII), IX (F.IX), and X (F.X), hemostasis proteins not associated with an acute-phase response, in a select population of horses with colic and hemostasis abnormalities, and presumed to have acute-phase changes. To compare these values and other routine hemostasis test results in the horses with colic with values for a population of healthy horses. To correlate the values of known equine acute-phase reactants, F.VIII:C and...
Malone ED, Kannan MS, Brown DR.To determine whether substance P (SP) functions as a neurotransmitter in equine jejunum. Methods: Samples of jejunum obtained from horses that did not have lesions in the gastrointestinal tract. Methods: Jejunal smooth muscle strips, oriented in the plane of the circular or longitudinal muscle, were suspended isometrically in muscle baths. Neurotransmitter release was induced by electrical field stimulation (EFS) delivered at 2 intensities (30 and 70 V) and various frequencies on muscle strips that were maintained at low tension or were under contraction. A neurokinin-1 receptor blocker (CP-96...
De Pedro P, Wilkins PA, McMichael MA, Dirikolu L, Lascola KM, Clark-Price SC, Boston RC.To determine endogenous production of L-lactate and the clearance of exogenous sodium L-lactate (ExLC) in healthy adult horses. Methods: A sodium L-lactate solution (1 mmol/kg body weight qs to 500 mL final volume in 0.9% NaCl) was adminstered IV over 15 minutes. Blood samples for L-lactate concentration [LAC] measurement were collected immediately prior to infusion, at 5, 10, and 15 minutes during infusion and at 1 minute intervals for 15 minutes, at 30, 45, 60, 120, and 180 minutes postinfusion. Disposition modeling and pharmacokinetic analysis was performed using proprietary software. Metho...
Davenport-Goodall CL, Boston RC, Richardson DW.To investigate the effects of insulin-like growth factor-II (IGF-II) on DNA and glycosaminoglycan (GAG) synthesis and the expression of matrix-related genes in equine articular cartilage explants and chondrocytes, respectively, with and without interleukin 1-beta (IL1-beta). Methods: Articular cartilage from 12 adult horses. Methods: Articular cartilage was incubated in standard media with and without equine IL1-beta (10 ng/mL) containing various concentrations of IGF-II for 72 hours. Synthesis of DNA and GAG was determined by incorporation of thymidine labeled with radioactive hydrogen (3H) a...
Vitale V, Berg LC, Larsen BB, Hannesdottir A, Dybdahl Thomsen P, Laursen SH, Verwilghen D, van Galen G.This pilot prospective study reports the feasibility, management and cost of the use of a continuous glucose monitoring (CGM) system in critically ill adult horses and foals. We compared the glucose measurements obtained by the CGM device with blood glucose (BG) concentrations. Neonatal foals (0-2 weeks of age) and adult horses (> 1 year old) admitted in the period of March-May 2016 with clinical and laboratory parameters compatible with systemic inflammatory response syndrome (SIRS) were included. Glucose concentration was monitored every 4 hours on blood samples with a point-of-care (POC) gl...
Current drug metabolismAugust 27, 2022
Volume 23, Issue 10 850-865 doi: 10.2174/1389200223666220825093945
Ishii H, Shibuya M, Kusano K, Sone Y, Kamiya T, Wakuno A, Ito H, Miyata K, Sato F, Kuroda T, Yamada M, Leung GN.Vadadustat, a hypoxia-inducible factor prolyl hydroxylase (HIF-PHD) inhibitor, is a substance which carries a lifetime ban in both horse racing and equestrian competition. A comprehensive metabolic study of vadadustat in horses has not been previously reported. Objective: Metabolism and elimination profiles of vadadustat in equine plasma and urine were studied for the purpose of doping control. Methods: A nasoesophageal administration of vadadustat (3 g/day for 3 days) was conducted on three thoroughbred mares. Potential metabolites were comprehensively detected by differential analysis of ful...
Ababneh MM, Troedsson MH.The aim of this study was to determine phospholipase A2 (PLA2) kinetics and activity in the mare's endometrium during the oestrous cycle and early pregnancy. Phospholipase A2 is responsible for the liberation of arachidonic acid from phospholipids, which is the first limiting step in prostaglandins synthesis. Phospholipase A2 activity was measured using an assay based on the liberation of oleic acid from 1-palmitoyl-2-[(14) C] oleoyl phosphatidylcholine. The enzyme was shown to be calcium dependent, to have an optimum pH of 8 and an apparent Michaelis constant of 127 μM. Enzyme activity was l...
van Loon JP, de Grauw JC, Brunott A, Weerts EA, van Weeren PR.Intra-articular injection of opioids provides analgesia in painful equine joints and μ-opioid receptors (MORs) have been demonstrated in equine synovial membranes. The aim of this study was to determine whether acute inflammatory conditions will lead to up-regulation of MOR in equine synovial membranes and whether anti-inflammatory treatment can prevent any such upregulation. In a two-period, blinded, placebo-controlled randomised cross-over design, lipopolysaccharide (LPS, 1.0 ng) was injected into the left or right middle carpal joint of seven healthy ponies. Arthroscopy and synovial membra...
Han X, Rossdale PD, Ousey J, Holdstock N, Allen WR, Silver M, Fowden AL, McGladdery AJ, Labrie F, Belanger A.15-hydroxy prostaglandin dehydrogenase (PGDH) is the critical enzyme that determines metabolism of primary prostaglandins. Its expression is determined in part by steroid hormones, particularly progesterone, formed from delta(5) steroids through 3beta-hydroxysteroid dehydrogenase (3beta-HSD) activity. To assess whether the regulation of PGDH might occur in a paracrine, autocrine or intracrine fashion, we used immunohistochemistry (IHC) to determine the localisation of key steroidogenic enzymes in the equine placenta and compared these patterns to the distribution of immunoreactive (IR-) PGDH. ...
Wagner AL, Urschel KL, Lefta M, Esser KA.To determine the effect of biopsy collection depth on the postprandial activation of mammalian target of rapamycin (mTOR) signaling factors, particularly protein kinase B, ribosomal protein S6 kinase, ribosomal protein S6, and eukaryotic initiation factor 4E binding protein 1 in middle-aged horses. Methods: 6 healthy Thoroughbred mares (mean ± SD age, 13.4 ± 3.4 years). Methods: Horses were fed a high-protein feed at 3 g/kg. Sixty minutes after horses were fed, the percutaneous needle biopsy technique was used to collect biopsy specimens from the gluteus medius muscle at 6, 8, and 10 cm belo...
Baumgartner WA, Storey ES, Paulsen DB.Intraocular choristomas are rare anomalies in domestic animals and are often associated with multiple ocular malformations. A Thoroughbred foal presented for ocular abnormalities and was diagnosed with microphthalmia, corneal dermoids, severe anterior segment dysgenesis (including glandular choristomas), aphakia, retinal dysplasia, and optic nerve hypoplasia. Morphological, histochemical, and immunohistochemical comparisons were made between ocular choristomatous tissues from this foal and lacrimal gland, third eyelid gland, nasopharynx, trachea, and lacrimal sac/nasolacrimal duct from normal ...
De Kock SS, Rodgers JP, Swanepoel BC, Guthrie AJ.This study investigated the biochemical effects of administration of three types of recombinant growth hormone (GH; somatotropin) to the Thoroughbred horse. Equine or bovine or porcine GH was administered at a recommended dosage to 3-5-year old Thoroughbred geldings, for up to 21 days. It was shown that, in addition to equine GH, bovine and porcine GH were active in the horse; however, porcine GH caused injection-site reactions that were so serious that administration had to be terminated. The concentrations of a range of GH-related serum protein markers were determined before, during and afte...
Kuroda T, Nagata S, Takizawa Y, Tamura N, Kusano K, Mizobe F, Hariu K.The pharmacokinetics of d-chlorpheniramine (CPM), a histamine H1-receptor antagonist, and its ability to inhibit of histamine-induced cutaneous wheal formation, were studied in healthy Thoroughbred horses (n=5). Following an intravenous (IV) dose of 0.5mg/kg bodyweight (BW), plasma drug disposition was very rapid, with the mean terminal half-life and total body clearance calculated as 2.7h and 0.7 L/h/kg, respectively. The observed maximal inhibition of wheal formation following IV doses of 0.1 and 0.5mg/kg BW were 37.8% and 60.6% at 0.5h, respectively. Oral administration of CPM (0.5mg/kg BW)...
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...
Höglund N, Koho N, Rossi H, Karttunen J, Mustonen AM, Nieminen P, Rilla K, Oikari S, Mykkänen A.Extracellular vesicles (EVs) are membrane-bound particles that engage in inflammatory reactions by mediating cell-cell interactions. Previously, EVs have been isolated from the bronchoalveolar lavage fluid (BALF) of humans and rodents. The aim of this study was to investigate the number and size distribution of EVs in the BALF of asthmatic horses (EA, = 35) and healthy horses ( = 19). Saline was injected during bronchoscopy to the right lung followed by manual aspiration. The retrieved BALF was centrifuged twice to remove cells and biological debris. The supernatant was concentrated and EVs w...
Norris JW, Pombo M, Shirley E, Blevins G, Tablin F.Two congenital bleeding diatheses have been identified in Thoroughbred horses: Glanzmann thrombasthenia (GT) and a second, novel diathesis associated with abnormal platelet function in response to collagen and thrombin stimulation. Objective: Platelet dysfunction in horses with this second thrombasthenia results from a secretory defect. Methods: Two affected and 6 clinically normal horses. Methods: Ex vivo study. Washed platelets were examined for (1) expression of the αIIb-β3 integrin; (2) fibrinogen binding capacity in response to ADP and thrombin; (3) secretion of dense and α-granules; (...
Mykkänen AK, Koho NM, Reeben M, McGowan CM, Pösö AR.Polymorphisms in human lactate transporter proteins (monocarboxylate transporters; MCTs), especially the MCT1 isoform, can affect lactate transport activity and cause signs of exercise-induced myopathy. Muscles express MCT1, MCT4 and CD147, an ancillary protein, indispensable for the activity of MCT1 and MCT4. We sequenced the coding sequence (cDNA) of horse MCT4 for the first time and examined polymorphisms in the cDNA of MCT1, MCT4 and CD147 of 16 healthy horses. To study whether signs of myopathy are linked to the polymorphisms, biopsy samples were taken from 26 horses with exercise-induced...
