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.
Torfs SC, Maes AA, Delesalle CJ, Deprez P, Croubels SM.Serotonin is regularly measured in equine platelet-poor plasma in research settings. However, reported reference values vary between studies, partially because plasma serotonin concentrations are very low and a reliable and affordable detection method is lacking. A simple, rapid, and sensitive method for serotonin determination in equine platelet-poor plasma using liquid chromatography--tandem mass spectrometry (LC-MS/MS) was developed and validated. Results of a commercially available enzyme-linked immunosorbent assay (ELISA) were compared to the LC-MS/MS results, in order to validate a test ...
Ho EN, Kwok WH, Wong AS, Wan TS.A recent trend in the use of high resolution accurate mass screening (HRAMS) for doping control testing in both human and animal sports has emerged due to significant improvement in high resolution mass spectrometry in terms of sensitivity, mass accuracy, mass resolution, and mass stability. A number of HRAMS methods have been reported for the detection of multi-drug residues in human or equine urine. As blood has become a common matrix for doping control analysis, especially in equine sports, a sensitive, fast and wide coverage screening method for detecting a large number of drugs in equine ...
Menéndez MI, Phelps MA, Hothem EA, Bertone AL.To determine the pharmacokinetics of methylprednisolone (MP) and the relationship between MP and hydrocortisone (HYD) concentrations in plasma and urine after intra-articular (IA) administration of 100 or 200 mg of MP acetate (MPA) to horses. Methods: Five 3-year-old Thoroughbred mares. Methods: Horses exercised on a treadmill 3 times/wk during the study. Horses received 100 mg of MPA IA, then 8 weeks later received 200 mg of MPA IA. Plasma and urine samples were obtained at various times for 8 weeks after horses received each dose of MPA; concentrations of MP and HYD were determined. Pharmaco...
Sevcik C, D'Suze G, Salazar V, Díaz P, Vázquez H.We used high sensitivity and resolution fluorescence microscopy to study the interaction of ostrich IgY, horse F(ab')₂ and horse IgG with mice lymphocyte and erythrocyte plasma membrane. The immunoglobulins were labeled with fluorescein isotiocyanate (FITC). Our results show an interaction of IgY with lymphocyte plasma membrane which does not result in endocytosis of the labeled protein. Less IgG and its F(ab')₂ fraction bind to lymphocytes, and this binding seems to be followed by endocytosis producing a diffuse cytoplasmic fluorescence in most lymphocytes exposed to FITC-IgG or FITC-F(ab...
Noble G, Edwards S, Lievaart J, Pippia J, Boston R, Raidal SL.Safety of meloxicam, a potent NSAID with selective COX-2 inhibition, has not been evaluated in horses. Objective: To evaluate pharmacokinetics and safety of single and repeated oral doses of meloxicam in adult horses. Methods: Forty-nine healthy, university-owned adult lightbreed horses. Methods: Study conducted in 2 parts. Part I addressed pharmacokinetics of single oral dose meloxicam (0.6 mg/kg) in 16 horses. Part II, 33 horses were randomly assigned to 5 treatment groups to assess prolonged administration (0.6 mg/kg PO q24h for 6 weeks, n = 7) or higher doses (1.8 mg/kg, n = 7, or 3.0 mg/k...
Stratford CH, Pemberton A, Cameron L, McGorum BC.Although a presumptive diagnosis of acute grass sickness (AGS) can be made on the basis of clinical signs, a definitive ante mortem diagnosis currently requires histological examination of enteric ganglia. Development of an accurate noninvasive ante mortem diagnostic test is therefore warranted. The objective of this study was to determine whether quantification of the plasma concentrations of the heavily phosphorylated form of major neurofilament subunit NF-H (pNF-H), which mirror the degree of axonal degeneration in some human and animal neurodegenerative disorders, could distinguish AGS-aff...
Ranjithkumar M, Malik TA, Saxena A, Dan A, Sakthivel PC, Dey S.Trypanosomiasis caused by Trypanosoma evansi commonly produces wasting disease with signs of emaciation and cachexia mainly at the end stage. The present study was conducted to explore the possible hyperlipaemia or hyperlipidaemia and its association with cachexia-anorexia in equine trypanosomiasis. Out of the fifteen confirmed animals, none of the plasma sample was opaque. There was a significant increase in plasma triglyceride, total cholesterol and blood urea nitrogen and a highly significant increase in low-density lipoprotein (LDL) levels. A mild increase in high-density lipoprotein (HDL)...
Slack J, Boston RC, Soma L, Reef VB.Upper reference limits for cTnI have not been established for healthy Standardbred racehorses. Objective: To establish cTnI upper reference limits for Standardbred racehorses and determine if increases in plasma cTnI concentration can be detected in 1-2 hours after a race. Methods: Samples were obtained from 586 apparently healthy Standardbreds aged 2-14 years before racing and from the winners of 144 races 1-2 hours after the end of the race. Methods: Prospective, observational study; convenience sampling; assay validation; and reference limits determinations were performed according to ASCVP...
Shrestha HK, Beg MA, Burnette RR, Ginther OJ.Horses are about five times more sensitive to the luteolytic effect of prostaglandin F2alpha (PGF) than cattle, as indicated by a recommended clinical dose of 5 mg in horses and 25 mg in cattle. Novel evaluations of the PGF plasma disappearance curves were made in mares and in heifers, and the two species were compared. Mares and heifers (n = 5) of similar body weight were injected (Min 0) intravenously with PGF (5 mg per animal). Blood was sampled every 10 sec until Min 3, every 30 sec until Min 5, every 10 min until Min 60, and every 30 min until Min 240. The mean PGF concentration was great...
Grubb T, Edner A, Frendin JH, Funkquist P, Rydén A, Nyman G.To assess oxygenation, ventilation-perfusion (V/Q) matching and plasma endothelin (ET-1) concentrations in healthy horses recovering from isoflurane anaesthesia administered with or without pulse-delivered inhaled nitric oxide (iNO). Methods: Prospective experimental trial. Methods: Healthy adult Standardbred horses. Methods: Horses were anaesthetized with isoflurane in oxygen and placed in lateral recumbency. Six control (C group) horses were anaesthetized without iNO delivery and six horses received pulse-delivered iNO (NO group). After 2.5 hours of anaesthesia isoflurane and iNO were abrupt...
Williams CA, Burk AO.The objective of this study was to determine if competition intensity would have an effect on antioxidant status in horses before and during a three-day event. Body weight, body condition score, and blood was sampled from CCI2* (n = 19) and CCI3* (n = 23) horses before the start of dressage, 20 to 30 min following cross-country, and 18-24 h after cross-county. Data were analyzed using a PROC MIXED in SAS. There were no differences between CCI2* and CCI3* horses during competition for plasma cortisol, lactate, α-tocopherol, retinol, or erythrocyte glutathione peroxidase. After cross-country, C...
Fielding CL, Magdesian KG, Meier CA, Rhodes DM.To describe the clinical and laboratory changes associated with the use of IV0.9% sodium chloride and a commercially available acetated fluid (CAF) to treat endurance horses requiring emergency medical treatment. Methods: Randomized, controlled clinical trial from 2007 to 2010. Methods: Emergency treatment centers of the Western States 100-mile (220 km) endurance ride. Methods: Twelve horses requiring emergency medical treatment in the form of IVfluids completed the study. Methods: Horses were assigned to either the 0.9% sodium chloride group (6 horses) or CAF group (6 horses) and received a t...
Radcliffe RM, Divers TJ, Fletcher DJ, Mohammed H, Kraus MS.To evaluate changes in plasma cardiac troponin I (cTnI) and L-lactate (LLt) as prognostic indicators in horses undergoing emergency abdominal surgery. Methods: Prospective observational study. Methods: Veterinary teaching hospital. Methods: Thirty-four horses undergoing emergency abdominal surgery. Methods: Serial blood sampling during various times during hospitalization (hospital admission, and 12, 24, 48, and 72 h postoperatively) evaluating cTnI and LLt concentrations. Results: All horses required surgery for correction of a strangulating (n = 29) or nonstrangulating obstruction (n = 5) of...
Söder J, Bröjer JT, Nostell KE.Systemic hypertension is a prominent feature in humans with metabolic syndrome (MS) and this is partly caused by an enhanced endothelin-1 (ET-1) mediated vasoconstriction. There are indications that systemic hypertension might be a feature in equine metabolic syndrome (EMS) but if ET-1 is involved in the development of hypertension in horses is not known. Increased levels of cortisol have also been found in humans with MS but there are no reports of this in horses. Before blood pressure, plasma ET-1 and serum cortisol can be evaluated in horses with EMS, it is necessary to investigate the inte...
Goodwin W, Keates H, Pasloske K, Pearson M, Sauer B, Ranasinghe MG.To determine the pharmacokinetics and pharmacodynamics of the neurosteroid anaesthetic, alfaxalone, in neonatal foals after a single intravenous (IV) injection of alfaxalone following premedication with butorphanol tartrate. Methods: Prospective experimental study. Methods: Five clinically healthy Australian Stock Horse foals of mean ± SD age of 12 ± 3 days and weighing 67.3 ± 12.4 kg. Methods: Foals were premedicated with butorphanol (0.05 mg kg(-1) IV) and anaesthesia was induced 10 minutes later by IV injection with alfaxalone 3 mg kg(-1) . Cardiorespiratory variables (pulse rate, respir...
Soma LR, Uboh CE, Liu Y, Li X, Robinson MA, Boston RC, Colahan PT.This study investigated and compared the pharmacokinetics of intra-articular (IA) administration of dexamethasone sodium phosphate (DSP) into three equine joints, femoropatellar (IAS), radiocarpal (IAC), and metacarpophalangeal (IAF), and the intramuscular (IM), oral (PO) and intravenous (IV) administrations. No significant differences in the pharmacokinetic estimates between the three joints were observed with the exception of maximum concentration (Cmax ) and time to maximum concentration (Tmax ). Median (range) Cmax for the IAC, IAF, and IAS were 16.9 (14.6-35.4), 23.4 (13.5-73.0), and 46.9...
Cordero M, Brorsen BW, McFarlane D.Cosinor analysis was used to evaluate whether pituitary and adrenal hormones exhibit circadian rhythmicity in horses. The effect of season and animal age on their respective rhythms was also determined. In addition, the usefulness of evaluating cortisol rhythmicity for the diagnosis of pituitary pars intermedia dysfunction (PPID) was assessed. Serum cortisol concentrations (P < 0.01), but not plasma ACTH or α-melanocyte-stimulating hormone (α-MSH), showed a significant circadian periodicity in horses. An effect of season on hormone concentration was observed with plasma ACTH and α-MSH co...
Ziska SM, Schumacher J, Duran SH, Brock KV.To develop a high-speed, continuous-flow, automated plasmapheresis procedure for the high-volume harvest of equine plasma in accordance with current good manufacturing practice. Methods: 143 horses (predominantly draft breeds) between 3 and 10 years of age at the time of purchase. Methods: Adaptations were made to automated plasmapheresis instruments and sterile disposable collection sets, which allowed for dual-instrument, continuous-flow operation. Donor horses were connected to the apparatus via 2 catheters (1 inserted in each jugular vein). The instruments removed whole blood from donors, ...
Ziska SM, Schumacher J, Duran SH, Brock KV.To determine the effects of intensive serial plasmapheresis on total plasma protein and total IgG concentrations in donor horses involved in a plasmapheresis program. Methods: 18 horses (13 mares and 5 geldings; 13 Belgians, 3 Percherons, 1 Standardbred, and 1 warmblood) ranging from 7 to 14 years of age (mean ± SD, 10 ± 3 years) and weighing 822 ± 128 kg. Methods: Horses from which 22 mL of plasma/kg of donor body weight was harvested at 14-day intervals for a minimum of 8 consecutive plasmapheresis donations were retrospectively selected for use in the evaluation. Automated plasmapheresis...
Bröjer JT, Nostell KE, Essén-Gustavsson B, Hedenström UO.To determine whether repeated oral administration of glucose and leucine during the period immediately after intense exercise would increase the release of insulin and thereby enhance glycogen synthesis in horses. Methods: 12 Standardbred horses. Methods: In a crossover study design, after glycogen-depleting exercise, horses received oral boluses of glucose (1 g/kg at 0, 2, and 4 hours) and leucine (0.1 g/kg at 0 and 4 hours) or boluses of water (10 mL/kg at 0, 2, and 4 hours; control treatment). Blood samples for determination of glucose, insulin, and leucine concentrations were collected pri...
Figueiredo JP, Muir WW, Sams R.To compare the cardiorespiratory, gastrointestinal, analgesic, and behavioral effects between IV and IM administration of morphine in conscious horses with no signs of pain. Methods: 6 healthy adult horses. Methods: Horses received saline (0.9% NaCl) solution (IM or IV) or morphine sulfate (0.05 and 0.1 mg/kg, IM or IV) in a randomized, masked crossover study design. The following variables were measured before and for 360 minutes after drug administration: heart and respiratory rates; systolic, diastolic, and mean arterial blood pressures; rectal temperature; arterial pH and blood gas variabl...
Nagel C, Erber R, Bergmaier C, Wulf M, Aurich J, Möstl E, Aurich C.The mechanisms leading to parturition in the horse in many aspects differ from those in other species. Pregnancy is maintained not by progesterone but by 5α-pregnanes and the progestin precursor pregnenolone originates from the fetus. As parturition approaches, the fetal adrenal switches from pregnenolone to cortisol synthesis but it is not known whether cortisol crosses the placenta. We hypothesized that in parallel to fetal cortisol release, cortisol in the maternal circulation increases before foaling and this increase can be determined in both saliva and plasma. In addition, maternal, fet...
Smiet E, Haritova A, Heil BA, Fink-Gremmels J, Wijnberg ID.To compare the pharmacokinetics of the fourth generation cephalosporin, cefquinome, in neonatal foals, 6-week-old foals and mature New Forest ponies in order to recommend appropriate dosage regimens for use of this drug. Methods: Cefquinome was administered i.v. at 1 mg/kg bwt twice a day (q. 12 h), 1 mg/kg bwt 3 times a day (q. 8 h) or 4.5 mg/kg bwt q. 12 h to each age group (n = 6). Plasma cefquinome concentrations were analysed using high-performance liquid chromatography combined with electrospray tandem mass spectrometry. Results: Both foal age groups had comparable pharmacokinetic data e...
Jellyman JK, Allen VL, Forhead AJ, Holdstock NB, Fowden AL.The effects of overexposure to glucocorticoids during early life of the foal on the subsequent HPA programming of the hypothalamic-pituitary-adrenal axis are unknown. Objective: To test the hypotheses that excess glucocorticoid exposure in early life subsequently increases both basal plasma concentrations of cortisol and the adrenocortical responsiveness to exogenous adrenocorticotropic hormone (ACTH). Methods: Foals received either saline (0.9% NaCl, n = 9) or long-acting ACTH (0.125 mg i.m. b.i.d., n = 6) for 5 days from Day 1 to increase endogenous cortisol concentrations. Long-term indwell...
Wang CC, Hartmann-Fischbach P, Krueger TR, Wells TL, Feineman AR, Compton JC.3,4-Methylenedioxypyrovalerone (MDPV) is a psychoactive drug with potent stimulant properties and potential for abuse and drug dependency. MDPV was recently classified as a Class I drug by Racing Commissioners International, indicating that it is a banned substance in equine athletes because it lacks therapeutic value in horses. To enforce this ban, a sensitive and fast liquid chromatography-tandem mass spectrometry method was needed. It is for this reason that this method was developed for quantification and confirmation of MDPV in equine plasma. Sample preparation involved liquid-liquid extr...
Lindinger MI, Ecker GL.Horses lose considerably more electrolytes through sweating during prolonged exercise than can be readily replaced through feeds. The present study tested an oral electrolyte supplement (ES) designed to replace sweat electrolyte losses. We measured gastric emptying of 3 litres of ES (using gamma imaging of (99)Tc-sulfide colloid), the absorption of Na(+) and K(+) from the gastrointestinal tract using (24)Na(+) and (42)K(+), and the distribution of these ions in the body by measuring radioactivity within plasma and sweat during exercise. Three litres of ES emptied from the stomach as fast as wa...
Retamal CA, Dias AJ, Brasil FC, Lanzana FR, López ML.The expression of α-D-mannosidase activity was fluorometrically and electrophoretically assessed in spermatozoa, epididymal fluid and homogenates of stallion epididymal tissue. Enzyme activity had regional differences; it was higher (P<0.05) in samples from the cauda epididymal region than in samples from the proximal caput region (largely composed of efferent ducts). Based on enzyme activity, as a function of pH of the assay substrate, electrophoretic analysis in native and native/SDS-PAGE conditions, and the effect of inhibitors or activators, we inferred the presence of at least two cat...
Iacono E, Merlo B, Pirrone A, Antonelli C, Brunori L, Romagnoli N, Castagnetti C.This paper documents the treatment of severe decubitus ulcers with amniotic fluid mesenchymal stem cells and platelets rich plasma (PRP) gel in a septic neonatal foal. The colt needed 25 days of hospitalization: during this period ulcers were treated for 15 days with mesenchymal stem cells (MSCs) plus PRP, PRP gel alone, or aloe gel. Healing was faster using MSCs+PRP, and at 7 months an ulcer treated with aloe gel was still not completely healed.
Mc Gowan TW, Pinchbeck GP, Mc Gowan CM.The sensitivity and specificity of basal plasma α-melanocyte-stimulating hormone (α-MSH) and adrenocorticotrophic hormone (ACTH) for the diagnosis of pituitary pars intermedia dysfunction (PPID) has not been evaluated in a population-based study. Objective: To evaluate basal plasma α-MSH and ACTH concentrations for the diagnosis of PPID in a population of horses aged ≥ 15 years. Methods: Owner-reported data were obtained using a postal questionnaire distributed to an equestrian group. A subgroup of surveyed owners was visited and veterinary examination performed on horses aged ≥ 15 year...
Jansson A, Lindberg JE.Most athletic horses are fed a high-starch diet despite the risk of health problems. Replacing starch concentrate with high-energy forage would alleviate these health problems, but could result in a shift in major substrates for muscle energy supply from glucose to short-chain fatty acids (SCFA) due to more hindgut fermentation of fibre. Dietary fat inclusion has previously been shown to promote aerobic energy supply during exercise, but the contribution of SCFA to exercise metabolism has received little attention. This study compared metabolic response with exercise and lactate threshold (VLa...
Edwards DF, Parker JW, Wilkinson JE, Helman RG.Plasma cell myelomas in horses have been reported infrequently. Data from 10 cases, 9 from the literature and 1 new case, are used to characterize the disease in the horse. Hot-blooded horses (7/10), specifically Quarter Horses (4/10), were most often affected. Median age at diagnosis was 11 years (range, 3 mo-22 yr) and both male (5) and female horses (5) were represented equally. Clinical findings included weight loss (6/8), anorexia (4/8), fever (4/8), limb edema (4/8), pneumonia (3/8), rear leg paresis/ataxia (3/8), epistaxis (3/8), palpable lymphadenopathy (2/8), and bone pain (2/8). Anem...
Schneiders FI, Noble GK, Boston RC, Dunstan AJ, Sillence MN, McKinney AR.Acepromazine (ACP) is a useful therapeutic drug, but is a prohibited substance in competition horses. The illicit use of ACP is difficult to detect due to its rapid metabolism, so this study investigated the ACP metabolite 2-(1-hydroxyethyl)promazine sulphoxide (HEPS) as a potential forensic marker. Acepromazine maleate, equivalent to 30mg of ACP, was given IV to 12 racing-bred geldings. Blood and urine were collected for 7days post-administration and analysed for ACP and HEPS by liquid chromatography-mass spectrometry (LC-MS). Acepromazine was quantifiable in plasma for up to 3h with little r...
McClure JT, DeLuca JL, Lunn DP, Miller J.The purpose of this study was to evaluate the ability of an equine plasma product i.v. and a concentrated serum product i.v. to deliver antibodies to 46 foals with failure of passive transfer (FPT). Treatment of FPT was as per manufacturers recommendations, using plasma (950 ml/unit) or a concentrated serum product (250 ml/unit). Significant variables affecting the 3 day post-transfusion serum immunoglobulin G (IgG) concentration of foals included body weight, pretransfusion IgG concentration, number of product units transfused, foaling season and product administered. Plasma treatment had a g...
Bamford NJ, Stewart AJ, El-Hage CM, Bertin FR, Bailey SR.Plasma adrenocorticotropic hormone (ACTH) concentration is commonly measured to diagnose pituitary pars intermedia dysfunction (PPID). Several intrinsic and extrinsic factors affect ACTH concentrations, including breed. The objective of this study was to prospectively compare plasma ACTH concentrations among different breeds of mature horses and ponies. Three breed groups comprised Thoroughbred horses (n = 127), Shetland ponies (n = 131) and ponies of non-Shetland breeds (n = 141). Enrolled animals did not show any signs of illness, lameness or clinical signs consistent with PPID. Blood ...
Raś A, Rapacz A, Raś-Noryńska M, Janowski TE.Cryptorchidism is a partial or total failure of testicular descent. For a proper diagnosis different methods are required. The main aim of this study was to compare different diagnostic methods. Sixty two horses (15 stallions, 32 cryptorchids and 15 geldings) were used in the experiment. They were clinically examined and ultrasonography was used to locate the testes. Blood samples were taken from the animals to measure the plasma level of testosterone and total estrogen (RIA method). In 22 horses suspected of cryptorchidism, the hCG stimulation test was performed. Blood samples were taken ever...
Khalil AM, Murakami N, Kaseda Y.Jugular vein blood samples were collected from 23 young and sexual mature feral stallions to examine the relationship between plasma testosterone concentration and age, breeding season or harem size. Testosterone concentration increased with the age of the stallions until they formed their own harems, at about 4 to 6 years old. Seasonal variations in testosterone concentrations were observed, and found to be significantly higher (P<0.001) throughout the breeding season than non-breeding season, from 3 years of age. Testosterone levels were correlated with harem size for individual stallions...
Lucke JN, Hall GN.Blood samples were taken before and immediately after 80 km and 40 km rides held on consecutive days and analysed for haematocrit, blood glucose and lactate, plasma sodium, potassium, calcium, albumin, free fatty acids (FFA), glycerol, bicarbonate, insulin, cortisol, glucagon, urea, creatinine, uric acid, bilirubin and alkaline phosphatase. Unusually hot weather probably contributed to haemoconcentration with a significant (P < 0.001) increase in haematocrit and plasma albumin. A fall in blood glucose, with a rise in FFA and glycerol were consistent with long distance riding and were associ...
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...
Horspool LJ, McKellar QA.The present study was designed to determine and compare the plasma disposition and pharmacokinetics of penicillin G sodium following intravenous (i.v.) administration to horses, ponies and donkeys. The plasma disposition and pharmacokinetics of penicillin G was similar in horses, ponies and donkeys (elimination half-lives--39.0, 27.3 and 31.5 min, respectively) and a dosage interval of 6-8 h would be suitable to treat infections caused by susceptible bacteria. Although penicillin G was absorbed rapidly following nasogastric administration, the systemic availability was low (0.12-0.34%), theref...
Clarke LL, Ganjam VK, Fichtenbaum B, Hatfield D, Garner HE.The effect of feeding frequency and associated meal size on the renin-angiotensin-aldosterone system (RAAS) in seven horses was examined. A daily maintenance ration of hay-grain pellets was provided either as a multiple feeding regimen (MF), in which the ration was divided into six equal portions fed at 4-h intervals, or as a single large feeding (SF) given from 9 A.M. until 11 A.M. Plasma renin activity (PRA), aldosterone (PAC), cortisol (PCC), protein concentration (TP), packed cell volume (PCV), and serum sodium and potassium were measured serially. To prevent significant RAAS stimulation d...
Cadario ME, Thatcher WW, Klapstein E, Merrit AM, Archbald LF, Thatcher MJ, LeBlanc MM.Two experiments were performed to investigate relationships between oxytocin, prostaglandin release, uterine emptying and fluid accumulation in the uterus. In Experiment 1, the effect of oxytocin on the pattern of prostaglandin release during uterine clearance of radiocolloid was measured in 5 normal mares and 5 mares with delayed uterine clearance. Uterine clearance was measured during estrus by scintigraphy at 0, 60 and 120 min after colloid infusion. After the 120-min reading, 20 IU, i.v., oxytocin were given, and the amount of colloid cleared was measured at 135, 150 and 180 min. Plasma wa...
Knych HK, Steffey EP, Mama KR, Stanley SD.To verify the isoflurane anesthetic minimum alveolar concentration (MAC)-sparing effect of a previously administered target plasma fentanyl concentration of 16 ng/mL and characterize an anticipated further sparing in isoflurane MAC associated with higher target plasma fentanyl concentrations. Methods: 8 horses. Methods: Horses were assigned 2 of 3 target plasma fentanyl concentrations (16, 24, and 32 ng/mL), administered in ascending order. Following determination of baseline MAC, horses received a loading dose of fentanyl followed by a constant rate infusion; MAC determination was performed i...
Colas C, Garcia P, Popot MA, Bonnaire Y, Bouchonnet S.Solid-phase extraction cartridges among those usually used for screening in horse doping analyses are tested to optimize the extraction of harpagoside (HS), harpagide (HG), and 8-para-coumaroyl harpagide (8PCHG) from plasma and urine. Extracts are analyzed by liquid chromatography coupled with multi-step tandem mass spectrometry. The extraction process retained for plasma applies BondElut PPL cartridges and provides extraction recoveries between 91% and 93%, with RSD values between 8 and 13% at 0.5 ng/mL. Two different procedures are needed to extract analytes from urine. HS and 8PCHG are extr...
Battaglia F, Meucci V, Tognetti R, Bonelli F, Sgorbini M, Lubas G, Pretti C, Intorre L.In human medicine, procalcitonin (PCT), the precursor of calcitonin, is used for the rapid identification of the origin and severity of sepsis. In veterinary medicine, PCT has been studied in horses, cattle, and dogs, but the use of PCT in diagnostic and/or prognostic settings is not possible because of the lack of validated assays to obtain reference ranges. The aim of the present study was the investigation of commercially available ELISA kits for the detection of canine and equine PCT in plasma samples. Validation of the ELISA kits was performed by using species-specific recombinant protein...
Törneke K, Ingvast-Larsson C, Pettersson K, Bergvall K, Hedeland M, Bondesson U, Broström H.Clemastine is an H1 antagonist used in certain allergic disorders in humans and tentatively also in horses, although the pharmacology of the drug in this species has not yet been investigated. In the present study we determined basic pharmacokinetic parameters and compared the effect of the drug measured as inhibition of histamine-induced cutaneous wheal formation in six horses. The most prominent feature of drug disposition after intravenous dose of 50 microg/kg bw was a very rapid initial decline in plasma concentration, followed by a terminal phase with a half-life of 5.4 h. The volume of d...
Berlin D, Aroch I.Magnesium (Mg) and calcium (Ca) are the main divalent cations in the body. The free ionized fraction is the physiologically active form of both Mg and Ca. As ion-selective-electrode (ISE) analyzers are becoming widely used in veterinary practice it will be useful to establish reference intervals for horses. In the present study, reference intervals were established for ionized, total and the ratio of the ionized to total Mg and Ca concentrations in four horse groups: adults, neonatal foals, and pregnant and lactating mares, as well as in three sample types, whole blood, plasma and serum, using...
Alvinerie M, Houin G, Toutain PL.The binding of prednisolone to total plasma proteins of dogs, horses, cows, and sheep was characterized using equilibrium dialysis. Prednisolone was bound to a first protein with high affinity but low capacity (transcortin) and to a second protein according to a nonsaturable mechanism (albumin). Interspecies differences were observed, with cows and dogs exhibiting the lowest, and sheep and horses the highest specific binding capacities. The results are in good agreement with known pharmacokinetic properties of prednisolone in domestic species.
Singh RK, Kooreman KM, Babbs CF, Fessler JF, Salaris SC, Pham J.The scavenging of superoxide radicals by endogenous and therapeutically administered superoxide dismutases may prevent superoxide-mediated oxidative stress leading to lipid peroxidation, membrane lysis, and cell death in a wide variety of normal and pathologic states. Simple inorganic manganous salts such as MnCl2 also have superoxide dismutase-like activity and are extremely inexpensive, compared with enzymatic superoxide dismutase preparations. In this study, we explored the use of Mn salts as antioxidant drugs. We used the percentage of inhibition of nitroblue tetrazolium reduction by super...
Bossut DF, Leshin LS, Stromberg MW, Malven PV.Electro-acupuncture (EA) treatment of horses to induce cutaneous analgesia also increased plasma concentrations of beta-endorphin (beta-EP) and cortisol. The magnitude of these increases did not relate consistently to the degree of EA-induced analgesia. Respiration and heart rates were also markedly increased during EA treatment. Intact female horses had higher packed cell volume and plasma beta-EP as well as lower plasma total protein than castrated male horses. Plasma cortisol, heart rate, and respiration rate did not differ significantly between sexes. None of the parameters measured before...
Papich MG, Van Camp SD, Cole JA, Whitacre MD.Enrofloxacin was administered i.v. to five adult mares at a dose of 5 mg/kg. After administration, blood and endometrial biopsy samples were collected at regular intervals for 24 h. The plasma and tissue samples were analyzed for enrofloxacin and the metabolite ciprofloxacin by high-pressure liquid chromatography. In plasma, enrofloxacin had a terminal half-life (t(1/2)), volume of distribution (area method), and systemic clearance of 6.7 +/- 2.9 h, 1.9 +/- 0.4 L/kg, and 3.7 +/- 1.4 mL/kg/min, respectively. Ciprofloxacin had a maximum plasma concentration (Cmax) of 0.28 +/- 0.09 microg/mL. In ...
Orsini JA, Moate PJ, Kuersten K, Soma LR, Boston RC.The safety and pharmacokinetics of fentanyl, delivered transdermally at a dosage of 60-67 microg/kg, were investigated in six healthy adult horses. Three transdermal fentanyl patches (Duragesic), each containing 10 mg of fentanyl citrate, were applied to the mid-dorsal thorax of each horse and left in place for 72 h. Plasma fentanyl concentrations were periodically measured throughout this period and for 12 h after patch removal. After an initial delay of approximately 2 h, the plasma fentanyl concentration rose rapidly in a fairly linear fashion, reaching a peak at around 12 h; thereafter, it...
Bardell D, Milner PI, Goljanek-Whysall K, Peffers MJ.Strangulating small intestinal disease (SSID) carries a poor prognosis for survival in comparison to other types of colic, particularly if resection is required. Identification of markers which aid early diagnosis may prevent the need for resection, assist with more accurate prognostication and/or support the decision on whether surgical intervention is likely to be successful, would be of significant welfare benefit. Objective: To apply an unbiased methodology to investigate the plasma and peritoneal fluid proteomes in horses diagnosed with SSID requiring resection, to identify novel biomarke...
Vervuert I, Coenen M, Bothe C.This study was conducted to evaluate the effects of different corn processing techniques on the glycaemic and insulinaemic responses in horses. It was hypothesized that the changes in pre-caecal starch digestibility caused by various types of corn processing would alter the post-prandial glycaemic and/or insulinaemic response. Six horses were fed in random order: untreated, finely ground, steamed, micronized, steam-flaked and popped corn. The total corn intake was adjusted to 630 g starch/horse/day (1.2-1.5 g starch/kg BW/day). During a stabilization period of 10 days, horses also received 6 k...
Elzinga SE, Rohleder B, Schanbacher B, McQuerry K, Barker VD, Adams AA.Extracts derived from the leaves of the stevia plant (stevioside) are commonly used as sweeteners for humans and horses. Stevioside appears to be safe for human consumption, including for individuals with insulin dysregulation. In the horse, the safety or metabolic effects of stevioside on normal animals or on those with metabolic dysfunction are unknown. Furthermore, the inflammatory response to a glycemic challenge or to stevioside in horses is not well defined. Therefore, the objective of this study was to measure the effects of stevioside and a glycemic challenge on insulin, glucose, and i...
Delatour P, Benoit E, Bourdin M, Gobron M, Moysan F.After the administration of racemic ketoprofen and carprofen to man, both enantiomers of each compound exhibit similar plasma profiles. This contrasts with the rat where the active S(+) enantiomer is predominant. For carprofen, regardless of the route of administration, the R(-) enantiomer is predominant in the plasma of all investigated animal species. The S(+)/R(-) ratio of the "areas under the curves" during the time course of the kinetics, is: 0.60 in dogs, 0.53 in Yucatan micro-pigs, 0.48 in mini-goats, 0.67 in calves and 0.19 in horses. For ketoprofen, the S(+) enantiomer is predominant ...
Nagy P, Solti L, Kulcsár M, Reiczigel J, Huszenicza G, Abaváry K, Wölfling A.Several assay systems (3H radioimmunoassay (RIA) with and without extraction; microplate enzyme-linked immunoassay (ELISA); qualitative ELISA (tube test)] were used to measure plasma progesterone concentration in mare plasma. The direct RIA showed a close correlation (R = 0.94) with the extraction RIA. The direct RIA and the microplate ELISA were compared in two different studies. In the first study 1155 samples of postpartum mares were used for progesterone determination with both assays. The ELISA resulted in more elevated values both in oestrus and dioestrus (0.19+/-0.3 and 2.44+/-3.62 nmol...
Ferjak EN, Cavinder CA, Burnett DD, Argo CM, Dinh TTN.Body condition score and percent body fat (BF; %) of horses are positively correlated with reproductive efficiency and are indicative of metabolic issues. However, BF in horses may be poorly predicted because current procedures are either subjective or dependent on one anatomical location. Therefore, the objectives of the current study were to compare 2 methods of predicting BF using rump fat thickness (RFT) and deuterium oxide (DO) dilution with actual tissue fat analysis by near-infrared spectroscopy (NIRS) in stock-type horses and to identify the relationship between BF and BCS. Twenty-four...
Massie SL, Bezugley RJ, McDonald KJ, Leguillette R.The prevalence and severity of cardiac arrhythmias in healthy racehorses undergoing competition is not well defined. The aim was to characterize arrhythmias in Thoroughbreds participating in official Chuckwagon races and to determine normal beat-to-beat (R-R) variability during supramaximal exercise. Electrocardiograph (ECG) recordings were obtained during pre-race, race, and active-recovery from 82 clinically healthy Thoroughbreds. ECG recordings were analyzed for arrhythmias and mean percent R-R deviation. Plasma lactate and high-sensitivity troponin (hs-cTnT) were also measured. Fifty-two E...
Reiffsteck A, Dehennin L, Scholler R.Estrone, 2-methoxyestrone and estradiol-17 beta have been definitely identified in seminal plasma of man, bull, boar and stallion by high resolution gas chromatography associated with selective monitoring of characteristic ions of suitable derivatives. Quantitative estimations were performed by isotope dilution with deuterated analogues and by monitoring molecular ions of trimethylsilyl ethers of labelled and unlabelled compounds. Concentrations of unconjugated and total estrogens are reported together with the statistical evaluation of accuracy and precision.
Art T, Franchimont P, Lekeux P.Ten horses underwent a standardised strenuous treadmill exercise test, before, during and after which measurements were made of plasma beta-endorphin and cortisol concentrations, blood lactate, glucose, haemoglobin and pH, the activities of creatine kinase, lactate dehydrogenase and aspartate amino-transferase, and heart rate, oxygen uptake and expired minute volume. The correlations between the exercise-induced response of beta-endorphin and the changes observed in the other physiological measurements were examined. There was a large variation in the beta-endorphin response of the horses to e...
