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.
REBERS PA, HURWITZ E, HEIDELBERGER M.Rebers, Paul A. (Rutgers University, New Brunswick, N. J.), Esther Hurwitz, and Michael Heidelberger. Immunochemistry of pneumococcal types II, V, and VI. II. Inhibition tests in the type VI precipitating system. J. Bacteriol. 82:920-926. 1961.-As in other immune systems involving polysaccharides, rabbit antibodies but not those engendered in the horse were found sensitive to degradation of type VI pneumococcal (Pn) polysaccharide (SVI), and were readily inhibited by fragments of SVI. Large amounts, 30 to 111 mumoles, of most sugars gave up to 15% inhibition, while sugar and polyol phosphates ...
BRAYE ET, HINSMAN EJ, RILEY WF.No horse receiving combined streptokinase, streptodornase, and human plasminogen alone in either 125,000-unit or 375,000-unit doses manifested any clinical reaction. Untoward reactions occurred in 2 horses receiving both the combined streptokinase, streptodornase, and human plasminogen (125,000 units), and chlortetracycline. The reaction was transitory and subsided without treatment.
Krueger CR, Klohnen A.To describe a technique for surgical correction of nephrosplenic entrapment via standing left flank laparotomy. Methods: Case series. Methods: Horses (n = 3). Methods: Nephrosplenic entrapment was diagnosed by abdominal palpation per rectum in all 3 horses and confirmed by transabdominal ultrasonography in 2 horses. Duration of colic was variable and failed to resolve after medical management, phenylephrine administration, and jogging. With sedation and local analgesia, standing left flank laparotomy using a modified grid approach was performed to correct the entrapment. Follow-up information ...
Zamith Cunha R, Zannoni A, Salamanca G, De Silva M, Rinnovati R, Gramenzi A, Forni M, Chiocchetti R.The metacarpophalangeal joint undergoes enormous loading during locomotion and can therefore often become inflamed, potentially resulting in osteoarthritis (OA). There are studies indicating that the endocannabinoid system (ECS) modulates synovium homeostasis, and could be a promising target for OA therapy. Some cannabinoid receptors, which modulate proliferative and secretory responses in joint inflammation, have been functionally identified in human and animal synovial cells. Unassigned: To characterize the cellular distribution of the cannabinoid receptors 1 (CB1R) and 2 (CB2R), and the can...
Komáromy AM, Andrew SE, Sapp HL, Brooks DE, Dawson WW.The goal of our study was the evaluation of a practical method for the recording of flash electroretinograms (ERGs) in sedated, standing horses with the DTL microfiber electrode. Methods: The horses were sedated intravenously with detomidine hydrochloride (0.015 mg/kg). The pupil was dilated and the auriculopalpebral nerve was blocked. The ERGs were recorded with the active electrode on the cornea (DTL), the reference electrode near the lateral canthus, and the ground electrode over the occipital bone. The light intensities of the white strobe light were 0.03 cd x s/m2 (scotopic) and 3 cd x s/...
Rodrigues VD, de Freitas MG, Milan B, Reckziegel GH, Borges DGL, Nakatani MTM, Tutija JF, Borges FA.The equine pinworm could become an increasingly common problem, as there are reports of failure in the control of this parasite. The aim of this study was to evaluate the effects of ivermectin (IVM) and IVM combined with pyrantel pamoate (PYR). Thirteen parasitological positive equines were treated with oral IVM (200 µg/kg) and therapeutic efficacy, clinical recovery and the egg reappearance period (ERP) were evaluated. In cases for which ERP was shorter than the pre-patent period (PPP), a second treatment was performed with IVM (200 µg/kg) + PYR (6.6 mg/kg), followed by the same evaluatio...
Hawkins JF, Couetil L, Miller MA.The objective was to evaluate CO2 laser debridement of the cricoarytenoid joint (CAJ) combined with prosthetic laryngoplasty to prevent post-operative loss of arytenoid abduction in seven horses. Horses were assigned to either laser debridement of the left CAJ and laryngoplasty (laser treated, n=5) or control laryngoplasty (sham, n=2), and were evaluated with endoscopic examinations and measurement of right to left angle quotients (RLQ) to assess maintenance of arytenoid abduction. The animals were euthanased at intervals after surgery and larynges were harvested for post-mortem testing, inclu...
McConnico RS, Argenzio RA, Roberts MC.The objective of this project was to determine early tissue biochemical events associated with increased colonic secretion during the acute stage of castor-oil-induced colitis by measuring cecal mucosal and submucosal malondialdehyde (MDA) and prostaglandin E2 (PGE2), levels in ponies. Intestinal tissue (inflamed or healthy) samples were obtained from 4 age- and sex-matched Shetland ponies. Biochemical methods were used to determine MDA and PGE2 levels in intestinal tissue samples from inflamed and healthy equine intestine. Inflamed tissue MDA and PGE2 levels increased with time after castor o...
Rossi SL, Guerbois M, Gorchakov R, Plante KS, Forrester NL, Weaver SC.Venezuelan equine encephalitis virus (VEEV) is an arbovirus that causes periodic outbreaks that impact equine and human populations in the Americas. One of the VEEV subtypes located in Mexico and Central America (IE) has recently been recognized as an important cause of equine disease and death, and human exposure also appears to be widespread. Here, we describe the use of an Internal Ribosome Entry Site (IRES) from encephalomyocarditis virus to stably attenuate VEEV, creating a vaccine candidate independent of unstable point mutations. Mice infected with this virus produced antibodies and wer...
McConnico RS, Stokes AM, Eades SC, Moore RM.To examine the secretory response (in the presence and absence of prostaglandin inhibition) in vitro and structural alterations of colonic mucosa in horses after intragastric administration of black walnut extract (BWE). Methods: 14 adult horses. Methods: Seven horses were administered BWE intragastrically and monitored for 11 hours. Tissue samples were obtained from the right ventral, left ventral, and right dorsal colons (RVC, LVC, and RDC, respectively) of the 7 BWE-treated and 7 control horses. Tissue samples were examined via light microscopy, and the extent of hemorrhage, edema, and gran...
Page AE, Wood C, Partridge E, Horohov DW, Adam E.The use of lipopolysaccharide to induce a localized source of inflammation (acute synovitis) and allow for monitoring of changes in systemic mRNA expression has been recently reported. Here, the goal was to maintain a significant systemic mRNA response while limiting the severity of lameness such that this model can be used to examine the effects of various anti-inflammatory treatment modalities on mRNA expression. Three mixed breeds, four-year-old geldings were utilized for this study. One milliliter of phosphate-buffered saline containing 1,000 ng or less of lipopolysaccharide from E. coli O...
Dyson DA, Smith GR.When incorporated in solid medium at a concentration of 15 per cent, the defibrinated blood of certain horses strongly suppressed the growth of some, but not all, strains of Mycoplasma mycoides subsp mycoides so that many colonies failed to develop to a visible size. Blood from a single rabbit was tested and found to exert a similar effect. There was striking variation in the degree of inhibition produced by different samples of horse blood and, of five strains of the organism examined, the T1 vaccine strain was the most susceptible. The results suggested that the effect was not due to antibod...
Scott JS, Broadstone RV, Derksen FJ, Robinson NE.Ponies with recurrent airway obstruction have hyperresponsive airways during acute disease exacerbations but not during clinical remission. We examined the effect of beta-adrenergic blockade with propranolol on airway responsiveness to aerosol histamine in six ponies with recurrent airway obstruction and six age- and gender-matched controls. Measurements were made with principal ponies in clinical remission (period A) and during an acute period of airway obstruction (period B). beta-Adrenergic blockade did not change airway responsiveness, dynamic compliance (Cdyn), or pulmonary resistance (RL...
Guillot J, Sarfati J, Ribot X, Jensen HE, Latgé JP.To detect antibodies against Aspergillus fumigatus antigens in serum samples from horses and to evaluate the relevance of this method as an alternative approach to the diagnosis of mycosis of the auditory tube diverticulum (guttural pouch mycosis [GPM]). Methods: Twelve clinically normal horses (controls) and 12 horses with GPM diagnosed by endoscopic observation of characteristic mycotic plaques. Methods: Antibodies to A fumigatus antigens were detected in serum by use of an ELISA and immunoblot analysis with extracellular antigens. Results: Antibodies against A fumigatus antigens were found ...
Ensink JM, Klein WR, Barneveld A, Vulto AG, Van Miert AS, Tukker JJ.The distribution of penicillins into a tissue chamber implanted subcutaneously in ponies was studied. Ampicillin sodium (equivalent to 15 mg/kg ampicillin) was administered intravenously. Pivampicillin, a prodrug of ampicillin, was administered by nasogastric tube to fed ponies at a dose of 19.9 mg/kg (equivalent to 15 mg/kg ampicillin). Procaine penicillin G was administered intramuscularly at a dose of 12 mg/kg (equivalent to 12000 IU/kg). Six ponies were used for each medication. Antibiotic concentrations in plasma and tissue chamber fluid (TCF) were measured for 24 h after administration. ...
Echeverria KO, Lascola KM, Giguère S, Foreman JH, Austin SA.OBJECTIVE To determine pharmacokinetics and pulmonary disposition of minocycline in horses after IV and intragastric administration. ANIMALS 7 healthy adult horses. PROCEDURES For experiment 1 of the study, minocycline was administered IV (2.2 mg/kg) or intragastrically (4 mg/kg) to 6 horses by use of a randomized crossover design. Plasma samples were obtained before and 16 times within 36 hours after minocycline administration. Bronchoalveolar lavage (BAL) was performed 4 times within 24 hours after minocycline administration for collection of pulmonary epithelial lining fluid (PELF) and BAL ...
Brink P, Smith RK, Tverdal A, Dolvik NI.To quantify concentrations of cartilage oligomeric matrix protein (COMP) and fibromodulin in synovial fluid from the tarsocrural joints (TCJs) of horses with osteochondritis dissecans (OCD) of the distal intermediate ridge of the tibia and determine whether concentrations would change following arthroscopic removal of osteochondral fragments. Methods: 115 client-owned horses with OCD of the TCJ and 29 control horses euthanized for unrelated reasons. Methods: COMP and fibromodulin concentrations were measured in synovial fluid from the TCJs of the affected horses before and after osteochondral ...
Boyle AG, Stefanovski D, Rankin SC.Streptococcus equi subsp equi (S. equi) is the cause of "equine strangles" which is a highly infectious upper respiratory disease. Detection of S. equi is influenced by site of specimen collection, method of sampling, and type of diagnostic test that is performed. We hypothesized i) that a loop-mediated isothermal amplification (LAMP) assay that targets the S. equi-specific eqbE gene would be more sensitive than a realtime PCR assay that targets the S. equi-specific seeI gene and ii) that LAMP of specimens obtained by guttural pouch lavage (GPL) would be more sensitive than LAMP of nasopharyng...
Bertone AL, Stashak TS, Sullins KE, Ralston SL.Ten normal horses had approximately 95% of the length of the large colon resected with a side-to-side anastomosis between right ventral and right dorsal colon performed with surgical stapling equipment. Four horses died shortly after surgery of colitis (1 horse) or failure of the TA 90 transection staple line (3 horses). Another horse died 4 months after surgery from disseminated streptococcal infection but had recovered well from the colon resection. Five horses survived long term (18 months) with no clinical evidence of adverse effects of the resection. Surviving horses had weight loss and s...
Takagi M, Nishimura K, Oguri N, Ohnuma K, Ito K, Takahashi J, Yasuda Y, Miyazawa K, Sato K.The viability of embryos before flushing from donor mares (n = 5) and after transfer to recipient mares (n = 7) was monitored in mare serum by detecting early pregnancy factor (EPF) using the rosette inhibition test (RIT). The EPF activity was measured in donor mares before and after natural mating at natural estrus; after ovulation on Days 2, 5 and 8; and after embryo flushing (Day 8) on Days 8, 9, 10 and 13 after ovulation. The collected embryos were transferred immediately after flushing. The EPF activity in recipient mares were measured on the day of transfer and after embryo transfer on D...
McClure SR, Miles K, Vansickle D, South T.The objective of this study was to evaluate the effects of variable waveform low-intensity ultrasound on the healing of a fracture gap of the fourth metacarpal bone in horses. A randomized, blinded, controlled trial was conducted in eight healthy adult horses. In each horse, a 1-cm osteotomy of the fourth metacarpal bone was created. One randomly selected metacarpal gap was treated daily with a 40-min session of ultrasound and the opposite gap was managed similarly with an inactive transducer. The fourth metacarpal bones were radiographed weekly. Fluorescent markers were administered at 14, 28...
Fischer BM, McMullen RJ, Reese S, Brehm W.Despite appropriate medical therapy, many horses with equine recurrent uveitis continue to suffer from recurrent bouts of inflammation. Surgical intervention via the pars plana vitrectomy or suprachoroidal cyclosporine implant placement may control and/or prevent recurrences, however, these procedures may be contraindicated, unavailable, or declined by an owner. Thus, an effective adjunctive treatment option may help to improve the clinical outcomes in those situations. There are several anecdotal reports on the use of intravitreal gentamicin injections, but to date, no data evaluating the com...
Broeckx SY, Maes S, Martinello T, Aerts D, Chiers K, Mariën T, Patruno M, Franco-Obregón A, Spaas JH.Besides the presence of somatic stem cells in hair follicles and dermis, the epidermis also contains a subpopulation of stem cells, reflecting its high regenerative capacity. However, only limited information concerning epidermis-derived epithelial-like stem/progenitor cells (EpSCs) is available to date. Nonetheless, this stem cell type could prove itself useful in skin reconstitution after injury. After harvesting from equine epidermis, the purified cells were characterized as EpSCs by means of positive expression for CD29, CD44, CD49f, CD90, Casein Kinase 2β, p63, and Ki67, low expression f...
Seewald LA, Sabino IG, Montney KL, Delco ML.To evaluate mitochondrial DNA (mtDNA) release from injured chondrocytes and investigate the utility of synovial fluid mtDNA concentration in early detection of posttraumatic osteoarthritis. We measured mtDNA release using four models of osteoarthritis: in vitro interleukin-1β stimulation of cultured equine chondrocytes, ex vivo mechanical impact of bovine cartilage explants, in vivo mechanical impact of equine articular cartilage, and naturally occurring equine intraarticular fracture. In our in vivo model, one group was treated with an intraarticular injection of the mitoprotective peptide S...
Bresnahan DR, Lupole RE, Stilz CR, Carnevale EM.Zona pellucida (ZP) proteins are important for fertilization and sperm binding and are closely associated with cumulus cells. Communication between cumulus and oocytes is facilitated by intracellular membrane channels composed of connexins. The extent aging impacts potential differences in fertilization and reductions in fertility is not well understood. This study characterized age-related differences in transcript abundance of ZP proteins and connexins in cells from ovarian follicles. Additionally, differences in sperm binding to oocytes from old and young mares was evaluated. For experiment...
Niinistö K, Hewetson M, Kaikkonen R, Sykes BW, Raekallio M.Prospective studies documenting the efficacy and side effects of medical treatment for colonic sand accumulation in horses are limited. The purpose of the study was to compare the effect of enteral administration of magnesium sulphate (MgSO4), psyllium mucilloid (psyllium), and a combination of MgSO4 and psyllium on the evacuation of large accumulations of sand in the large colon of adult horses. Thirty-four horses with naturally acquired, large sand accumulations (>5 cm × 15 cm) identified on abdominal radiography were randomly allocated to one of three treatment groups: (1) 1 g/kg...
Estrada RJ, Alvarado GJ, Vargas A, Vargas J, Vargas D, Chacón R, Razquin P, Vindas R.To determine the proximal diffusion distance of radiopaque contrast medium and mepivacaine/methylene blue solution and incidence of inadvertent intrasynovial and intravascular injections of modified sesamoid nerve block (MASB) when compared with traditional plantar nerve analgesia techniques of the equine distal hind limb. Methods: Ex vivo model: 18 hind limbs; and in vivo model: 5 horses in a crossover study. Methods: In the ex vivo model, a mepivacaine/methylene blue solution was used to compare the diffusion distance between MASB, basisesamoid block (BSB), and traditional low plantar block ...
Sampieri F, Allen AL, Alcorn J, Clark CR, Vannucci FA, Pusterla N, Mapes SM, Ball KR, Dowling PM, Thompson J, Bernstein LR, Gebhart CJ, Hamilton DL.Antimicrobial efficacy against Lawsonia intracellularis is difficult to evaluate in vitro, thus, the effects of gallium maltolate's (GaM) were investigated in a rabbit model for equine proliferative enteropathy (EPE). Juvenile (5-6-week-old) does were infected with 3.0 × 10(8) L. intracellularis/rabbit and allocated into three groups (n = 8). One week postinfection, one group was treated with GaM, 50 mg/kg; one, with doxycycline, 5 mg/kg; and one with a sham-treatment (control). Feces and blood were collected daily and weekly, respectively, to verify presence of L. intracellularis fec...
Olson LE.We evaluated the pressure-flow relationships in collaterally ventilating segments of excised pony lungs by infusing N2, He, Ne, or SF6 at known flows (V) through a catheter wedged in a peripheral airway. Measurements were made at segment- (Ps) to-airway opening (Pao) pressure differentials of 3-15 cmH2O when the lungs were held at transpulmonary pressures of 5, 10, and 15 cmH2O. The data were analyzed both by calculating collateral resistance (Ps-Pao/V) and by constructing Moody-type plots of normalized pressure drop [(Ps-Pao)/(1/2 rho U2, where rho is density and U is velocity)] against Reyno...
Zhang J, Go YY, Huang CM, Meade BJ, Lu Z, Snijder EJ, Timoney PJ, Balasuriya UB.A stable full-length cDNA clone of the modified live virus (MLV) vaccine strain of equine arteritis virus (EAV) was developed. RNA transcripts generated from this plasmid (pEAVrMLV) were infectious upon transfection into mammalian cells, and the resultant recombinant virus (rMLV) had 100% nucleotide identity to the parental MLV vaccine strain of EAV. A single silent nucleotide substitution was introduced into the nucleocapsid gene (pEAVrMLVB), enabling the cloned vaccine virus (rMLVB) to be distinguished from parental MLV vaccine as well as other field and laboratory strains of EAV by using an...
Hinrichs K, Riera FL.Ten mares were used to investigate the effect of administration of prostaglandin F2 alpha on uterine tubal motility, as reflected by embryo recovery from the uterus 5 days after ovulation (day 0). Mares were assigned to 3 groups: group A, uterine flush for embryo recovery on day 7; group B, uterine flush for embryo recovery on day 5; and group C, uterine flush for embryo recovery on day 5, after treatment with prostaglandin F2 alpha (10 mg, IM) on day 3. Each mare was assigned to each group once. Embryo recovery rates for the 3 groups were: A, 6 of 10; B, 2 of 8; and C, 0 of 10. The embryo rec...
Drudge JH, Lyons ET, Tolliver SC.Critical tests were carried out in 10 horses to evaluate the antiparasitic activity of febantel given alone or with trichlorfon. Paste formulations were administered intraorally at dose levels of 6 mg of febantel (active ingredient)/kg and 35 mg of trichlorfon (active ingredient)/kg. In 5 tests with febantel alone, removal of 100% was recorded for mature or immature Parascaris equorum from 2 infected horses. Strongylus vulgaris from 4 infected horses, S edentatus from 5 infected horses, and mature Oxyuris equi from 1 infected horse; and removal of 96% was recorded for small strogyles from 1 ho...
