Plasma is the liquid component of blood in horses, consisting primarily of water, electrolytes, proteins, and waste products. It serves as a transport medium for nutrients, hormones, and waste products throughout the body. Plasma also plays a role in maintaining blood pressure and volume, as well as serving as a reservoir for critical proteins involved in clotting and immune responses. Research on equine plasma often focuses on its composition, functions, and applications in veterinary medicine, such as transfusions and diagnostic testing. This page compiles peer-reviewed research studies and scholarly articles that explore the properties, functions, and clinical applications of plasma in equine health.
Moreira CJC, De Cicco NNT, Galdino TS, Feder D, Gonzalez MS, Miguel RB, Coura JR, Castro HC, Azambuja P, Atella GC, Ratcliffe NA, Mello CB.Chagas disease, infecting ca. 8 million people in Central and South America, is mediated by the protozoan parasite, Trypanosoma cruzi. The parasite is transmitted by the bite of blood sucking triatomine insects, such as Rhodnius prolixus, that had previously fed on parasite-infected vertebrate blood and voided their contaminated feces and urine into the wound. The stages of the parasite life cycle in both the insect vector and human host are well-known, but determinants of infection in the insect gut are complex and enigmatic. This paper examines the possible role of the R. prolixus gut agglut...
Axmann S, Hummel K, Nöbauer K, Razzazi-Fazeli E, Zitterl-Eglseer K.Devil's claw is used for the treatment of inflammatory symptoms and degenerative disorders in horses since many years, but without the substantive pharmacokinetic data. The pharmacokinetic parameters of harpagoside, the main active constituent of Harpagophytum procumbens DC ex Meisn., were evaluated in equine plasma after administration of Harpagophytum extract FB 8858 in an open, single-dose, two-treatment, two-period, randomized cross-over design. Six horses received a single dose of Harpagophytum extract, corresponding to 5 mg/kg BM harpagoside, and after 7 days washout period, 10 mg/kg ...
Grubb TL, Kurkowski D, Sellon DC, Seino KK, Coffey T, Davis JL.Buprenorphine is absorbed following sublingual administration, which would be a low-stress delivery route in foals. However, the pharmacokinetics/pharmacodynamics are not described in foals. Six healthy foals <21 days of age participated in a blinded, randomized, 3-period, 5-sequence, 3-treatment crossover prospective study. Foals received 0.01-0.02 mg/kg buprenorphine administered SL or IV with an equivalent volume of saline administered by the opposite route. Blood was collected from the cephalic vein for pharmacokinetic analysis. Physiologic parameters (HR, RR, body temperature, GI sou...
Levionnois OL, Graubner C, Spadavecchia C.To investigate the pharmacological profile and side effects of buprenorphine administered as a sustained-release formulation in horses. Methods: Pilot trial. Methods: A total of four experimental horses, aged 18-27 years and weighing 508-578 kg. Methods: Buprenorphine (0.1 mg kg) was mixed as a freshly prepared sterile solution with a sustained-release drug carrier. It was administered by the subcutaneous (n = 2) or intramuscular (n = 2) route. During the experiment, the horses were closely monitored, equipped with a step counter and blood samples were collected for quantification of bup...
Machin J, Duer W, Maylin G, Fenger C, Wilson D, Ivey M, Berthold B, Allison S, Tobin T.Methylprednisolone (MP) acetate is a commonly used corticosteroid for suppression of inflammation in synovial structures in horses. Its use is often regulated in equine sports by plasma MP concentrations. Objective: To describe variability in MP plasma concentrations after MP acetate injection in different synovial structures and with co-administration with hyaluronic acid (HA). Methods: Field study in actively racing horses in three disciplines (Thoroughbred, Standardbred and Quarter Horse). Methods: Seventy-six horses (15 Thoroughbreds, 20 Standardbreds and 41 Quarter Horses) were included i...
Knych HK, Arthur RM, McKemie DS, Baden R, Oldberg N, Kass PH.Flumetasone is a potent corticosteroid reportedly used in horses to decrease inflammation associated with strenuous exercise. There are currently no reports describing the use of this drug in horses. Objective: To describe the pharmacokinetics and effects on cortisol and eicosanoid concentrations, following administration of flumetasone to exercised horses. Methods: Parallel design. Methods: Twelve exercised horses received a single i.v. administration of 5 mg of flumetasone. Blood and urine samples were collected before and for 72 h post-drug administration for determination of flumetasone an...
Lee EB, Kim JW, Seo JP.Platelet rich plasma (PRP) is popularly used in the horse industry to enhance regeneration of tissue injury that has limitation of blood supply. This study aimed to compare the methods for platelet rich plasma preparation since they has not been established yet. Blood was collected from six horses and platelets were concentrated by three different methods (2-step centrifugation, separated centrifugation and separated centrifugation using histopaque). Concentrated blood was analyzed using Advia hematology systems. In the result, separated centrifugation with histopaque showed the significantly ...
Wang J, Xue J, Kong J, Li J, Zhang S, Cao X.The pharmacokinetic properties of vitacoxib have not been established completely; current dosage recommendations are based on clinical experiences. The primary objective of this study was to describe plasma concentrations and characterize the pharmacokinetics of vitacoxib formulation following oral administrations in horses. Also, the effect of the state of stomach contents on the absorption of vitacoxib was investigated in fed/fasted horses. Blood samples were collected prior to and at various times up to 72 hr post-administration. Drug concentrations were measured using ultra high-performan...
Fontenot RL, Langston VC, Zimmerman JA, Wills RW, Sloan PB, Mochal-King CA.To determine meropenem concentrations in radiocarpal (RC) joint fluid and plasma after intravenous regional limb perfusion (IVRLP). Methods: In vivo experimental study. Methods: Nine healthy adult mares. Methods: Meropenem (500 mg) was injected in the forelimb of standing sedated horses via IVRLP with a pneumatic tourniquet inflated to 400 mmHg. Synovial fluid was collected from RC joints at 0, 0.5, 1, 2, 4, 6, 8, 12, and 18 hours after meropenem injection. Blood samples were collected from the jugular vein at the same time points and at 5 and 15 minutes following injection. Meropenem concentr...
Stein F, Gilliam L, Davis J, Taylor J.In a randomized crossover design study, 10 adult horses were administered crushed metronidazole tablets rectally at 20 mg/kg. Horses' rectums were either evacuated (E) or not evacuated (NE) of manure prior to the administration of the drug. Serum samples were taken over 24 hr and plasma concentrations were determined via high pressure liquid chromatography. At 15 min post-administration, group E had a significantly higher plasma concentration (p = 0.027), but there were no concentration differences at any other time points. There was large variability in relative bioavailability in the NE...
Finding EJT, Lawson C, Elliott J, Harris PA, Menzies-Gow NJ.Microvesicles are small (up to 1 μm) vesicles found in plasma and other bodily fluids. They are recognised as part of the normal system of inter-cellular communication but altered numbers are also used as biomarkers of disease. Microvesicles have not been studied in detail in the horse but may be relevant to diseases such as laminitis. Identification of equine cell specific microvesicles was performed by developing a panel of cross reactive antibodies to use in flow cytometry to detect microvesicles of platelet, leucocyte and endothelial origin in plasma from healthy ponies and those predis...
Zak A, Siwinska N, Slowikowska M, Borowicz H, Szpot P, Zawadzki M, Niedzwiedz A.Capsaicin and dihydrocapsaicin are alkaloids with analgesic effects in humans and animals. When used locally, both of them minimalise pain sensation by defunctionalising nerve endings. According to the Federation Equestrian International Prohibited Substances List, these are substance banned in horse competitions. The aim of the study was to determine the detection time of capsaicin in both plasma and serum after long-term use of a gel recommended for commercial use and applied as intended. The objective of the study was to select the best material for the detection of capsaicin as a doping su...
Jarrett MA, Bailey KM, Messenger KM, Prange T, Gaines B, Posner LP.OBJECTIVE To evaluate quality of recovery from general anesthesia in horses after induction with propofol and ketamine versus midazolam and ketamine. DESIGN Prospective randomized crossover study. ANIMALS 6 healthy adult horses. PROCEDURES Horses were premedicated with xylazine (1.0 mg/kg [0.45 mg/lb], IV), and general anesthesia was induced with midazolam (0.1 mg/kg [0.045 mg/lb], IV) or propofol (0.5 mg/kg [0.23 mg/lb], IV), followed by ketamine (3.0 mg/kg [1.36 mg/lb], IV). Horses were endotracheally intubated, and anesthesia was maintained with isoflurane. After 60 minutes, horses were giv...
DeBoer ML, Hathaway MR, Kuhle KJ, Weber PSD, Reiter AS, Sheaffer CC, Wells MS, Martinson KL.Elevated nonstructural carbohydrate (NSC) values in pasture forages can cause adverse health effects in some horses (Equus caballus L.). The objectives of this study were to determine the impact of different forage species on blood glucose and insulin concentrations of horses throughout the grazing season. Research was conducted in July (summer) and September (fall) in St. Paul, MN. Alfalfa (Medicago sativa L.), mixed perennial cool-season grasses (CSG), and teff (Eragrostis tef [Zucc.] Trotter) pastures were grazed by six horses (24 ± 2 years) that were randomly assigned to one of three for...
Roska S, Morello S, Rajamanickam V, Smith LJ.Effects of lactated Ringer's solution (LRS) and hetastarch 130/0.4 (HES) on colloid osmotic pressure (COP), plasma osmolality (OSM) and total protein (TP) were investigated in 18 inhalational-anaesthetised healthy horses. Horses received 4-6 ml/kg LRS (LRS; n=9) or HES (HES; n=9) from anaesthesia induction through 60 min, after which all were administered LRS. COP, TP and OSM were measured before premedication (baseline), postinduction and 30 (n=18), 60 (n=18), 90 (n=18) and 120 (n=12) minutes. Baseline COP, OSM and TP were not different between groups. TP decreased in both groups at all t...
Ortved KF.Tendon and ligament injuries are a common source of lameness in the athletic horse. Although tendons and ligaments have the ability to spontaneously heal, lesions tend to fill with biomechanically inferior fibrous tissue such that the horse is prone to reinjury. Regenerative medicine is used to improve quality of repair tissue and prevent reinjury. Platelet-rich plasma, stem cells, and autologous conditioned serum are the most commonly used orthobiologics in the horse. A tailored rehabilitation program is key to returning horses to athleticism following injury. The specifics of regenerative me...
Tosi I, Bureau F, Farnir F, Denoix JM, Lekeux P, Art T.Cytosine-phosphate-guanosine (CpG-ODN) has been described as a potent immunostimulatory agent in different species. No study reported the effect of a P-class CpG when administered systemically in healthy horses. The aim of this study was to evaluate the tolerance and the effect of an intramuscularly administered P-class CpG-ODN on hematology and on plasma cytokines (IFN-α, IL-10, TNF-α, IFN-γ) in 8 healthy horses. Intra-muscular CpG-ODN or placebo (PBS) was administered twice at a 7 days-interval. Groups were inversed after 2 months of washout period. A physical examination, complete bloo...
Pakkanen SAE, de Vries A, Raekallio MR, Mykkänen AK, Palviainen MJ, Sankari SM, Vainio OM.Romifidine, an α-2 adrenoceptor agonist, is a widely-used sedative in equine medicine. Besides the desired sedative and analgesic actions, α-2 adrenoceptor agonists have side effects like alterations of plasma concentrations of glucose and certain stress-related hormones and metabolites in various species. Vatinoxan (previously known as MK-467), in turn, is an antagonist of α-2 adrenoceptors. Because vatinoxan does not cross the blood brain barrier in significant amounts, it has only minor effect on sedation induced by α-2 adrenoceptor agonists. Previously, vatinoxan is shown to prevent th...
Kenéz Á, Warnken T, Feige K, Huber K.Insulin dysregulation in horses is a metabolic condition defined by high insulin concentrations in the blood and peripheral insulin resistance. This hyperinsulinemia is often associated with severe damage in the hooves, resulting in laminitis. However, we currently lack detailed information regarding the potential involvement of particular metabolic pathways in pathophysiological causes and consequences of equine insulin dysregulation. This study aimed to assess the dynamic metabolic responses given to an oral glucose test (OGT) in insulin-sensitive and insulin-dysregulated horses by a targete...
Pearson W, Wood K, Stanley S, MacNicol J.Obesity is associated with inflammatory disorders in humans, including degenerative joint disease. While obesity is endemic in horses, its relationship to equine degenerative joint disease has not been explored. The current study sought to describe relationships between: body weight (BW), body condition score (BCS), lameness grade (AAEP), total body fat mass (kg; FM) and fat per cent (FP) [multifrequency bioelectrical impedance analysis (mfBIA)], age, gender, activity level (AL), synovial fluid (SF) and plasma (PL) PGE and glycosaminoglycan (GAG) in horses. During this field investigation, the...
Williams T, Rude B, Liao S, Mochal-King C, Nicodemus M.The objective of this study was to observe how fat incorporated into an equine forage-based diet through supplementation altered levels of plasma glucose, insulin and fatty acids. Five Shetland/Hackney cross pony mares were fed alfalfa pellet diets top dressed with commercially available vegetable oil (blend of soya bean, canola and corn oils) at 0%, 5%, 10% or 15% of diet. Ponies were randomly assigned one of four diets to start, with a 14-day adjustment period between transitioning to another one of the four diets. Ponies were gradually adapted to the new diet within the 14-day period before...
Viu J, Armengou L, Decloedt A, Jose-Cunilleras E.Two horses referred to the Unitat Equina, Fundació Hospital Clínic Veterinari, Universitat Autònoma de Barcelona, for unrelated clinical problems, and with no previous history of cardiac disease exhibited an intermittent ventricular pre-excitation electrocardiographic pattern during hospitalization. Both animals showed decreased plasma total and ionized magnesium concentrations, but no other relevant electrolyte disturbances were detected. Altered interventricular septal motion associated with ventricular pre-excitation beats (VPBs) was detected on M-mode echocardiography in both horses. Th...
Bachmann M, Czetö A, Romanowski K, Vernunft A, Wensch-Dorendorf M, Wolf P, Metges CC, Zeyner A.Postprandial alterations of plasma amino acid (PAA) levels partly reflect a temporal contribution of the feed. How cereal grains affect PAA levels is not known. We hypothesized that a meal of cereal grains causes a temporal increase of PAA, affected by grain species, grain genotype and meal size. Six mares were used in three consecutive trials, receiving four oats, barley and maize genotypes, respectively. Individual grain genotypes were provided as 3 meal sizes corresponding to 1.0, 1.5 or 2.0 g starch/kg body weight. Meadow hay (1.5 kg/100 kg body weight) was offered daily. At the test...
Rosenstein PG, Tennent-Brown BS, Hughes D.To review the current literature pertaining to the use of lactate as a prognostic indicator and therapeutic guide, the utility of measuring lactate concentrations in body fluids other than blood or plasma, and the clinical management of hyperlactatemia in dogs, cats, and horses. Methods: Articles were retrieved without date restrictions primarily via PubMed, Scopus, and CAB Abstracts as well as by manual selection. Unassigned: Increased plasma lactate concentrations are associated with increased morbidity and mortality. In populations with high mortality, hyperlactatemia is moderately predicti...
Liu Y, Siard M, Adams A, Keowen ML, Miller TK, Garza F, Andrews FM, Seeram NP.The human health benefits attributed to turmeric/curcumin spice has resulted in its wide utilization as a dietary supplement for companion pets and other animals including horses. While the quantification of free curcuminoids (curcumin, demethoxycurcumin, bisdemethoxycurcumin) and their phase-2 metabolites (curcumin-O-sulfate, curcumin-O-glucuronide) have been extensively investigated in human and rodent biological samples (primarily plasma and serum), there is lack of similar data for horses. Herein, we report a validated LC-ESI-MS/MS method for the simultaneous quantification of the aforemen...
D'Ascola A, Bruschetta G, Zanghì G, Campo S, Medica P, Campana S, Ferlazzo G, Gibbs BF, Ferlazzo AM.Serotonin (5-HT) is a neurohormone transported from plasma into platelets and leukocytes by a specific transporter (SERT). While it is known that the brain 5-HT system is modulated by physical exercise, the peripheral serotoninergic response to exercise is not yet fully elucidated. In particular, this study aimed to evaluate changes in plasma 5-HT levels and equine leukocyte SERT expression in response to treadmill exercise in untrained horses. Analyses were carried out pre- and post-treadmill exercise. 5-HT plasma levels were analysed by HPLC. Leukocytes and platelets were isolated to perform...
Oberhaus EL, Thompson DL, Foster BA, Pinto CR.This experiment assessed the hormonal production, secretory aspects, and changes in luteinizing hormone (LH) receptor gene expression of early induced ovulatory-sized follicles relative to the first ovulatory-sized follicles occurring naturally in the spring. Anovulatory mares were treated on January 21 with (1) 50 mg of estradiol cypionate (ECP, n = 8) alone or (2) with ECP followed by two 3-g sulpiride injections (n = 8), 5 and 12 days later. Half of each group also received complete follicle ablation via transvaginal aspiration before ECP treatment. Ovaries were scanned regularly until ...
Viljanto M, Hillyer L, Hincks P, Pearce C, Paine SW.Medication control and doping control have been established in horse racing to ensure the integrity of the sport and the welfare of the horses. This ensures that horses do not compete under the influence of any drugs, including omeprazole, a therapeutic medication used to treat equine gastric ulcer syndrome. In this study, pharmacokinetic data were produced in equine plasma and urine following an oral administration of 4 mg/kg of generic buffered formulation of omeprazole to six Thoroughbred horses in five daily doses to determine an appropriate screening limit and detection time in equine pl...
Pille F, De Baere S, Ceelen L, Dewulf J, Croubels S, Gasthuys F, De Backer P, Martens A.To determine radiocarpal (RC) joint synovial fluid and plasma ceftiofur concentrations after regional intravenous perfusion (RIP) and systemic intravenous (IV) administration. Methods: Experimental cross-over study. Methods: Five normal adult horses. Methods: One RC joint was randomly selected for RIP and the contralateral RC joint was sampled to determine intrasynovial ceftiofur concentrations after IV administration. Wash-out between IV and RIP was > or = 14 days. After surgical introduction of an intraarticular catheter, ceftiofur (2 g) was administered under general anesthesia either IV or...
Buff PR, Messer NT, Cogswell AM, Johnson PJ, Keisler DH, Ganjam VK.The objective of this study was to determine if seasonal and/or pulsatile variations occur in plasma concentrations of thyrotropin (TSH) and leptin in mares while maintaining a constant energy balance. Blood samples were collected every 20 min during a 24h period in winter and again in summer from six Quarter Horse type mares. Plasma concentrations of TSH, leptin, and T(4) were determined by radioimmunoassay. No differences were observed in body weight between winter (388.1+/-12.5 kg) and summer (406.2+/-12.5 kg; P=0.11). Plasma concentrations of TSH were greater in the summer (2.80+/-0.07 ng/...
Watson TD, Burns L, Love S, Packard CJ, Shepherd J.Plasma lipoproteins were isolated from eight Thoroughbred horses and eight Shetland ponies on the basis of particle size by gel filtration chromatography and according to density using rate-zonal ultracentrifugation. Three major classes corresponding to very low density lipoproteins (VLDL), low density lipoproteins (LDL) and high density lipoproteins (HDL) were identified and characterised by their lipid and apolipoprotein compositions. The particle size distributions of each class were determined by electron microscopy and non-denaturing polyacrylamide gradient gel electrophoresis. HDL was fo...
White A, Reyes A, Godoy A, Martínez R.1. Packed cell volume (PCV), blood glucose, total plasma proteins (TPP) and plasma electrolytes, osmolality, cortisol and aldosterone alterations produced by transport and racing, were investigated in race horses. 2. Plasma cortisol, sodium and blood glucose, found after transport, were higher, while aldosterone was lower than control levels. 3. After racing, PCV, blood glucose, TPP and plasma cortisol, sodium and osmolality were higher than control, while chloride diminished and aldosterone returned to control values. 4. These results demonstrate that transport and racing are different kinds ...
Thompson DL, Hoffman R, DePew CL.Eight pony mares received 4 mg of recombinant porcine prolactin (rpPRL) daily for 45 d beginning on January 15; eight control mares received vehicle. Reproductive end points and various indicators of metabolism, hair shedding, and thyroid activity were monitored. Prolactin concentrations peaked in mares treated with rpPRL at 94 +/- 19 ng/mL 2 h after injection and were 5.1 +/- 1.7 ng/mL 24 h after injection. Treatment with rpPRL increased (P < .01) hair shedding within 14 d, which peaked at 28 d and then dropped precipitously. Binding of 125I-equine prolactin confirmed that antibodies were ...
Crisman MV, Wilcke JR, Sams RA.To determine pharmacokinetic variables that describe the disposition of flunixin after i.v. administration of flunixin meglumine to foals < 24 hours old. Methods: 6 healthy foals, 2 males and 4 females (mean age, 11.6 hours; range, 6 to 22.5 hours). Methods: Flunixin (as flunixin meglumine) was administered to foals at a dosage of 1.1 mg/kg of body weight. Flunixin concentration in plasma samples was analyzed, using gas chromatography/mass spectroscopy. Concentration versus time profiles were analyzed according to standard pharmacokinetic techniques. Blood samples were obtained from foals by j...
Meulyzer M, Vachon P, Beaudry F, Vinardell T, Richard H, Beauchamp G, Laverty S.To compare synovial glucosamine levels in normal and inflamed equine joints following oral glucosamine administration and to determine whether single dose administration alters standard synovial parameters of inflammation. Methods: Eight adult horses were studied. On weeks 1 and 2, all horses received 20mg/kg glucosamine hydrochloride by nasogastric (NG) intubation or intravenous injection. On weeks 3 and 4, 12h after injection of both radiocarpal joints with 0.25 ng Escherichia coli lipopolysaccharide (LPS) to induce inflammation, glucosamine hydrochloride or a placebo was administered by NG ...
Bermingham EC, Papich MG, Vivrette SL.To determine the pharmacokinetics of enrofloxacin administered IV and orally to foals. Methods: 5 clinically normal foals. Methods: A 2-dose cross-over trial with IV and oral administration was performed. Enrofloxacin was administered once IV (5 mg/kg of body weight) to 1-week-old foals, followed by 1 oral administration (10 mg/kg) after a 7-day washout period. Blood samples were collected for 48 hours after the single dose IV and oral administrations and analyzed for plasma enrofloxacin and ciprofloxacin concentrations by use of high-performance liquid chromatography. Results: For IV administ...
Lillich JD, Rakestraw PC, Roussel AJ, Finley MR, Ganta S, Freeman LC.To determine whether ether-a-go-go (ERG) potassium channels are expressed in equine gastrointestinal smooth muscle, whether ERG channel antagonists affect jejunal muscle contraction in vitro, and whether plasma cisapride concentrations in horses administered treatment for postoperative ileus (POI) are consistent with ERG channels as drug targets. Methods: Samples of intestinal smooth muscle obtained from 8 horses free of gastrointestinal tract disease and plasma samples obtained from 3 horses administered cisapride for treatment of POI. Methods: Membranes were prepared from the seromuscular la...
Davis JL, Messenger KM, LaFevers DH, Barlow BM, Posner LP.The purpose of this study was to determine the pharmacokinetics of buprenorphine following intravenous (i.v.) and intramuscular (i.m.) administration in horses. Six horses received i.v. or i.m. buprenorphine (0.005 mg/kg) in a randomized, crossover design. Plasma samples were collected at predetermined times and horses were monitored for adverse reactions. Buprenorphine concentrations were measured using ultra-performance liquid chromatography with electrospray ionization mass spectrometry. Following i.v. administration, clearance was 7.97±5.16 mL/kg/min, and half-life (T(1/2)) was 3.58 h (ha...
Connysson M, Rhodin M, Jansson A.This study examined the effects of two housing systems (free-range and box stalls) on recovery of energy balance after competition-like exercise in Standardbred horses. Eight adult geldings (mean age 11 years) were used. The study had a change-over design, with the box stall (BOX) and free-range group housing (FreeR) treatments each run for 21 days. The horses were fed forage ad libitum and performed two similar race-like exercise tests (ET), on day 7 and day 14 in each treatment. Forage intake was recorded during the last 6-7 days in each period. Blood samples were collected before, during, a...
Heidler B, Aurich JE, Pohl W, Aurich C.This study summarizes weight development, plasma glucose concentrations and reproductive parameters in lactating (n = 46) and non-lactating Lipizzaner mares (n = 11) throughout the breeding season. It was the aim of the study to analyse if an energy deficit with possible effects on reproductive functions occurs at any time during the first 4 months of gestation. Mean gestation length was 334.3 +/- 7.3 days. Gestation of foals born in May/June was shorter (P < 0.01) than for foals born in March/April. Out of the 46 lactating mares, 44 ovulated between Days 8 and 18 postpartum and two mares ovul...
Alcott CJ, Sponseller BA, Wong DM, Davis JL, Soliman AM, Wang C, Hsu W.Ketamine has immunomodulating effects both in vitro and in vivo during experimental endotoxemia in humans, rodents, and dogs. Objective: Subanesthetic doses of ketamine will attenuate the clinical and immunologic responses to experimental endotoxemia in horses. Methods: Nineteen healthy mares of various breeds. Methods: Experimental study. Horses were randomized into 2 groups: ketamine-treated horses (KET; n = 9) and saline-treated horses (SAL; n = 10). Both groups received 30 ng/kg of lipopolysaccharide (LPS, Escherichia coli, O55:B5) 1 hour after the start of a continuous rate infusion (CRI)...
Grulke S, Franck T, Gangl M, Péters F, Salciccia A, Deby-Dupont G, Serteyn D.Gastrointestinal disorders, especially strangulating intestinal obstructions, are still a major cause of illness and death in the horse. Circulating lipopolysaccharides may activate both neutrophils and monocytes. The activated neutrophils release myeloperoxidase (MPO), a specific enzyme with strong oxidative activity. The aim of this study was to evaluate MPO concentrations in the plasma and peritoneal fluid (PF) of horses with colic and to check the hypothesis that these concentrations would be higher in a case of strangulating obstruction than in cases of nonstrangulating disease. By using ...
Rossdale PD, Ousey JC, Silver M, Fowden A.This paper describes criteria used to assess maturity of the newborn foal and their clinical application to field cases of prematurity and dysmaturity. Premature and mature foals may be clearly distinguished by their behavioural and physical characteristics. Measurement of haematological parameters (mean cell volume, total white cell and differential counts), pancreatic beta cell activity (plasma glucose and insulin levels), adrenocortical-medullary function (plasma cortisol, adrenocorticotrophic hormone and catecholamines) and the renin-angiotensin system (plasma renin substrate concentration...
Nolan A, Reid J, Welsh E, Flaherty D, McCormack R, Monteiro AM.The pharmacokinetics of propofol and ketamine administered together by infusion were investigated in four ponies. Blood propofol and plasma ketamine and norketamine concentrations were measured by high performance liquid chromatography. After premedication with detomidine (20 micrograms kg-1) anaesthesia was induced with ketamine (2.2 mg kg-1 intravenously). The trachea was intubated and the ponies were allowed to breathe 100 per cent oxygen. A bolus dose of propofol (0.5 mg kg-1) was then administered intravenously and propofol and ketamine were infused for 60 and 45 minutes, respectively. Th...
Passler NH, Chan HM, Stewart AJ, Duran SH, Welles EG, Lin HC, Ravis WR.The purpose of this study was to assess safety and alterations in body fluid concentrations of voriconazole in normal horses on days 7 and 14 following once daily dose of 4 mg/kg of voriconazole orally for 14 days. Body fluid drug concentrations were determined by the use of high performance liquid chromatography (HPLC). On day 7, mean voriconazole concentrations of plasma, peritoneal, synovial and cerebrospinal fluids, aqueous humor, epithelial lining fluid (ELF), and urine were 1.47 +/- 0.63, 0.61 +/- 0.22, 0.70 +/- 0.20, 0.62 +/- 0.26, 0.55 +/- 0.32, 79.45 +/- 69.4, and 1.83 +/- 0.44 microg...
Sgorbini M, Bonelli F, Marmorini P, Biagi G, Corazza M, Pasquini A.The aim of the present work was to evaluate derivated reactive oxygen metabolites (d-ROMs) and biological antioxidant potential (BAP) in mares and foals to study perinatal oxidative status. A total of 60 animals were included in the present study. Maternal and foal venous blood samples were collected immediately after delivery along with a sample drawn from one of the umbilical arteries, and plasma samples were evaluated for lactatemia, d-ROMs, and BAP. The t test for unpaired data was applied between mares versus umbilical artery blood versus foals, both for d-ROMs and BAP. The Pearson test w...
Medica P, Bruschetta G, Cravana C, Ferlazzo A, Fazio E.The objective of current study was to evaluate the effect of transportation stress on the circulating adrenaline (A), noradrenaline (NA) and dopamine (DA) responses of stallions, according to the different distances. Forty-two stallions were studied before and after road transportation of 100, 200 and 300km, for a period of 1-3h. An increase in plasma A after 100km (P<0.001) was observed. A similar result was seen in plasma NA after 100km (P<0.001), and 300km (P<0.001). Increases in plasma DA after 100 and 200km (P<0.0001) were observed, with a decrease after 300km (P<0.0001). S...
Urschel KL, Escobar J, McCutcheon LJ, Geor RJ.Little is known about the role insulin plays in regulating whole-body and muscle protein metabolism in horses. The objective of this study was to determine the effects of graded rates of insulin infusion on plasma amino acid concentrations and the activation of factors in the mechanistic target of rapamycin signaling pathway in the skeletal muscle of horses. Isoglycemic, hyperinsulinemic clamp procedures were conducted in 8 mature, thoroughbred mares receiving 4 rates of insulin infusion: 0 mU · kg(-1) · min(-1) (CON), 1.2 mU · kg(-1) · min(-1) (LOWINS), 3 mU · kg(-1) · min(-1) (MEDINS),...
Rezende ML, Wagner AE, Mama KR, Ferreira TH, Steffey EP.To determine effects of a continuous rate infusion of lidocaine on the minimum alveolar concentration (MAC) of sevoflurane in horses. Methods: 8 healthy adult horses. Methods: Horses were anesthetized via IV administration of xylazine, ketamine, and diazepam; anesthesia was maintained with sevoflurane in oxygen. Approximately 1 hour after induction, sevoflurane MAC determination was initiated via standard techniques. Following sevoflurane MAC determination, lidocaine was administered as a bolus (1.3 mg/kg, IV, over 15 minutes), followed by constant rate infusion at 50 μg/kg/min. Determination...
Kilcoyne I, Nieto JE, Dechant JE.To determine the ability of plasma and peritoneal creatine kinase (CK) to predict the presence of a strangulating lesion in horses presented for colic. Methods: Prospective clinical study. Methods: Ten healthy control horses and 61 clinical colic cases. Methods: Creatine kinase activity was measured in peritoneal fluid and plasma of 10 healthy horses and 61 horses presenting for colic (40 horses with nonstrangulating lesions and 21 horses with strangulating lesions). Information on other blood and peritoneal fluid variables, signalment, results from the physical examination, outcome, requireme...
Wagner AE, Bednarski RM, Muir WW.The hemodynamic effects of high arterial carbon dioxide pressure (PaCO2) during anesthesia in horses were studied. Eight horses were anesthetized with xylazine, guaifenesin, and thiamylal, and were maintained with halothane in oxygen (end-tidal halothane concentration = 1.15%). Baseline data were collected while the horses were breathing spontaneously; then the horses were subjected to intermittent positive-pressure ventilation, and data were collected during normocapnia (PaCO2, 35 to 45 mm of Hg), moderate hypercapnia (PaCO2, 60 to 70 mm of Hg), and severe hypercapnia (PaCO2, 75 to 85 mm of H...
McGivney BA, Griffin ME, Gough KF, McGivney CL, Browne JA, Hill EW, Katz LM.Circulating miRNAs (ci-miRNAs) are endogenous, non-coding RNAs emerging as potential diagnostic biomarkers. Equine miRNAs have been previously identified including subsets of tissue-specific miRNAs. In order to investigate ci-miRNAs as diagnostic tools, normal patterns of expression for different scenarios including responses to exercise need to be identified. Human studies have demonstrated that many ci-miRNAs are up-regulated following exercise with changes in expression patterns in skeletal muscle. However, technical challenges such as haemolysis impact on accurate plasma ci-miRNA quantific...
Schneider NR, Yeary RA.Elimination kinetics of nitrite and nitrate in the dog, sheep, and pony were determined. The elimination half-lives of nitrite were 0.499, 0.475, and 0.566 hours in the dog, sheep, and pony, respectively; those of nitrate were 44.681, 4.233, and 4.821 hours. Apparent specific volumes of distribution (V'd) of nitrite were variable among the 3 species--1,623.7 ml/kg in the dog, 278.0 ml/kg in the sheep, and 191.6 ml/kg in the pony. The V'd of nitrate were less varied--dog, 238.5 ml/kg; sheep, 291.1 ml/kg; and pony, 209.3 ml/kg. In the in vitro studies on protein binding in canine plasma, the ext...
Knych HK, Steffey EP, Casbeer HC, Mitchell MM.Foal responses to a broader range of plasma fentanyl concentrations than currently reported are desirable to support (or not) clinical use. Objective: To describe fentanyl plasma concentrations following an escalating i.v. fentanyl dosing schedule in foals aged 5-13 days and describe selected, associated dose- and time-related behavioural and physiological responses to plasma fentanyl concentration. Methods: Experimental. Methods: Fentanyl was administered i.v. in an escalating fashion (2, 4, 8, 16 and 32 μg/kg bwt) at 10-min intervals. Blood samples were collected before and at selected time...
de la Rebière de Pouyade G, Riggs LM, Moore JN, Franck T, Deby-Dupont G, Hurley DJ, Serteyn D.Laminitis is a local manifestation of a systemic inflammatory response that is characterized by neutrophil activation and movement of neutrophils into the laminar tissues. Given the evidence for the involvement of neutrophils in the development of laminitis, we measured concentrations of neutrophil elastase, a serine protease released from the azurophilic granules of neutrophils, in plasma, skin and laminar tissues obtained from control horses and horses given black walnut heartwood extract (BWHE) to induce laminitis. Healthy horses (5-15 years old) were randomly assigned to 4 groups: 3 experi...
Knowles EJ, Moreton-Clack MC, Shaw S, Harris PA, Elliott J, Menzies-Gow NJ.Analysis of plasma adrenocorticotropic hormone concentration [ACTH] aids diagnosis of pituitary pars intermedia dysfunction (PPID). Comparisons of the validated chemiluminescent-immunoassay (CI) and immunofluorescent (IF) assays are limited. Objective: To compare the results of [ACTH] analysis by CI and IF methods of samples collected in autumn and spring and assess cross-reactivity. Methods: Method comparison. Methods: Plasma from nonlaminitic ponies was analysed concurrently using the IF and CI methods in autumn and the following spring. Diagnostic thresholds for the IF method were derived u...
Mirza MH, Oliver JL, Seahorn TL, Hosgood G, Moore RM.The purpose of this study was to determine whether nitric oxide (NO) is present in clinically normal horses under basal conditions and if it increases secondary to naturally acquired small intestinal strangulation obstruction. Thirty-one horses were used; 20 horses with naturally acquired small intestinal strangulation obstruction and 11 clinically normal horses with no signs of gastrointestinal tract disease. Jugular venous blood, abdominal fluid, and urine were collected for NO quantification. Plasma, abdominal fluid, and urine were stored at -70 degrees C until analyzed for NO using a chemi...
Ono K, Inui K, Hasegawa T, Matsuki N, Watanabe H, Takagi S, Hasegawa A, Tomoda I.The change in activities of 3 major antioxidative enzymes in equine erythrocytes, superoxide dismutase (SOD), glutathione peroxidase (GSHpx), and catalase, was investigated in order to evaluate the effect of exercise. Blood samples were obtained from 11 thoroughbred horses before and immediately after vigorous exercise which induced the increase of plasma lipid peroxide (Lpx) concentration from 1.16 +/- 0.40 nmol/ml to 1.29 +/- 0.34 nmol/ml. Following the exercise, the GSHpx activity in erythrocytes was significantly reduced from 69 +/- 10 IU/gHb to 65 +/- 8 IU/gHb, whereas SOD and catalase ac...
