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.
Thane K, Uricchio C, Frank N.Diagnosis of pituitary pars intermedia dysfunction (PPID) using the thyrotropin-releasing hormone (TRH) stimulation test requires blood collection 10 minutes after TRH injection; it is unknown if small differences in timing affect test results. Objective: To determine whether early or late sampling results in a significant (≥10%) difference in plasma adrenocorticotropic hormone (ACTH) concentration compared to standard 10-minute sampling. Methods: Twenty-four healthy adult horses with unknown PPID status. Methods: In this prospective study, subjects underwent a single TRH stimulation test, ...
Fuentes-Romero B, Muñoz-Prieto A, Cerón JJ, Martín-Cuervo M, Iglesias-García M, Aguilera-Tejero E, Díez-Castro E.Obesity and its associated complications, such as metabolic syndrome, are an increasing problem in both humans and horses in the developed world. The expression patterns of resistin differ considerably between species. In rodents, resistin is expressed by adipocytes and is related to obesity and ID. In humans, resistin is predominantly produced by inflammatory cells, and resistin concentrations do not reflect the degree of obesity, although they may predict cardiovascular outcomes. The aim of this study was to investigate the usefulness of resistin and its relationship with ID and selected ind...
Niikura T, Tsogtgerel M, Niikura C, Wada H, Kanzawa S, Fujiwara T, Nambo Y.The objective of this study was to examine the effect of prostaglandin F2α (dinoprost) and oxytocin administration on uterine polymorphonuclear neutrophil counts in the Japanese heavy draft mare. To compare polymorphonuclear neutrophil (PMN) counts in the endometrium, a total of 162 samples were collected from 54 estruses of 47 mares (before ovulation, day 0, and day 2) using a double-guarded cytology brush. Dinoprost (PG; 5 mg) was administered intramuscularly (i.m.) only once, on day 0, whereas oxytocin (OT; 20 U i.m.) was administered three times at 12-hr intervals starting on day 0. The p...
Fazio E, Lindner A, Cravana C, Wegener J, Medica P, Hart-Mann U, Ferlazzo A.This study examined how a standard exercise test (SET) affected (1) thyroid hormones (THs) of horses and (2) the relationship between the V of horses and TH responses to the exercise in trained Standardbred racehorses (V is the velocity run at defined conditions at which a blood lactate concentration of 4 mmol/L is determined). Twelve trained Standardbred racehorses (six stallions and six mares) performed SETs until the horses' blood lactate concentration was at or above 4 mmol/L. The horses were divided into three age groups (2, 3, and 4 years old); each group consists of 4 horses respectivel...
Mendoza FJ, Buzon-Cuevas A, Toribio RE, Perez-Ecija A.Insulin dysregulation (ID) is diagnosed in horses and ponies using oral glucose (OGTT) and oral sugar (OSTT) tolerance tests. The enteroinsular axis plays a major role in postprandial glucose disposal and insulin response in horses, ponies and foals. The insulin and incretin response to oral carbohydrate challenges has not been characterised in donkeys. Objective: (a) To characterise OGTT and OSTT, and (b) to assess the plasma incretin response to OGTT and OSTT in healthy donkeys. Methods: In vivo experiments. Methods: Six healthy adult female Andalusian donkeys were challenged with OGTT (1 g...
Williams MR, Holbrook TC, Maxwell L, Croft CH, Ientile MM, Cliburn K.Cannabidiol (CBD) products have gained popularity among horse owners despite limited evidence regarding pharmacokinetics. The purpose of this study was to describe the pharmacokinetic profile of multiple doses of an orally administered cannabidiol product formulated specifically for horses. A randomized 2-way crossover design was used. Seven horses received 0.35 or 2.0 mg/kg CBD per os every 24 hours for 7 total doses, separated by a 2-week washout. Plasma CBD and delta-9-tetrahydrocannabinol (THC) were quantified using liquid chromatography-tandem mass spectrometry (LC-MS/MS) daily through da...
Luethy D, Robinson MA, Stefanovski D, Haughan J, Torcivia C, Kowalski A, Ford M, You Y, Missanelli J, Slack J.Cardiac drugs with defined pharmacological parameters in horses are limited. The objective of this study was to characterize the pharmacokinetic properties and cardiovascular effects of intravenous and oral metoprolol tartrate (MET) in horses. In a 2-period randomized cross-over design, MET was administered IV (0.04 mg/kg) and PO (6 mg/kg) once to six healthy adult horses. Horses were monitored via continuous telemetry and non-invasive blood pressure (NIBP). Blood samples were serially collected for 72 h post-administration, and concentrations were determined by LC-MS/MS. Pharmacokinetics w...
Fouché N, Gerber V, Bruckmaier RM, Erni-Wespi B, Zander Y, Vidondo B, Sieme H, Claes A, Kaeser R, Burger D.Anti-Müllerian Hormone (AMH) has been linked to reproductive tract abnormalities in mares and stallions. This study aimed at evaluating AMH as a biomarker for two reproductive conditions in mares. In the first part of this study, plasma AMH was evaluated as an early indicator of the onset of cyclicity in mares in the transitional period from the anovulatory phase during winter anoestrus to the cyclic phase during the breeding season. Ten mares between 8 and 17 years old were included in the experiment which lasted from mid-February until the end of April. Ovarian activity was monitored with u...
Drews B, Milojevic V, Robles M, Wimel L, Dubois C, Rudolf Vegas A, Giller K, Chavatte-Palmer P, Daniel H, Giesbertz P, Bruckmaier RM, Ulbrich SE.Female mammalian reproductive functions are closely linked to body condition and metabolic status. Energy homeostasis is regulated by endocrine hormones such as insulin, IGF-I, leptin, and adiponectin via the hypothalamic-pituitary-adrenal axis. These metabolic hormones and their receptors are also expressed in reproductive tissues and the embryo. We investigated the relationship between circulating leptin and the fatty acid (FA) and amino acid (AA) composition of the equine uterine fluid (UF) and peripheral blood plasma (BP) by using a mass spectrometry-based approach. UF and BP were collecte...
Moura TCM, Arruda LCP, Araújo Silva RAJ, Silva RPF, Oliveira AS, Tobal LFM, Batista AM, Carneiro GF, Guerra MMP.The aim of this study was to investigate the effects of sucrose on post-thawed equine semen quality. Semen samples (n = 24) were collected from six stallions. They were diluted (200 × 10 sperm/mL) in a freezing medium based on skimmed milk, egg yolk, dimethylformamide, and supplemented with sucrose at concentrations of 0 (Control), 25, 50, and 100 mM and in a commercial extender (BotuCrio). Subsequently, they were filled in straws (0.5 mL) and subjected to freezing and storage (-196°C). Immediately after thawing (37°C, 30 seconds), semen samples were evaluated for kinetics (CASA), plasm...
Fielding CL, Magdesian KG.To evaluate changes in electrolyte concentrations and hydration status that take place in endurance horses prior to the start of a competition and determine whether these changes would be associated with elimination. Methods: 19 horses entered in the 2016 Tevis Cup 100-Miles (160 km) One-Day Western States Trail Ride. Methods: Heparinized blood samples were collected at 5 time points: prior to transport to the ride (T0), during check-in the day before the ride (T1), 1 to 2 hours before the start of the ride (T2), at the 15-km mark (T3), and at the 55-km mark (T4). Packed cell volume and plasma...
Kuroda T, Minamijima Y, Nomura M, Yamashita S, Yamada M, Nagata S, Mita H, Tamura N, Fukuda K, Kuwano A, Kusano K, Toutain PL, Sato F.For medication control in several jurisdictions, withdrawal time is the period of refrain from racing after drug administration. It is set by adding a safety period to an experimental detection time. However, there are no reports of statistical analyses of detection time for the determination of withdrawal time in flunixin meglumine-treated horses. Objective: To analyse the population pharmacokinetics of flunixin in horses through the generation of a dataset for detection time statistical analysis and predictions via Monte Carlo simulation. Methods: Experimental study. Methods: Drug plasma and...
Suagee-Bedore J, Shost N, Miller C, Grado L, Bechelli J.Older horses and those prone to obesity may be at a higher risk for inflammation than younger and leaner counterparts. Previous research indicated a postprandial elevation in plasma concentrations of interleukin-1β (IL-1β), a pro-inflammatory cytokine, after consuming 1.2 g of non-structural carbohydrates/kilogram of body weight. However, these studies utilized horses of mixed age and body condition. The current study evaluated post-prandial IL-1β concentrations in horses specifically comparing lean to over-conditioned and middle aged to older. Our results suggest that at least two weeks of...
Liu CC, Hsiao YC, Chu LJ, Wang PJ, Liu CH, Hsieh WC, Yu JS., also known as Taiwanese cobra, is one of the most prevalent venomous snakes in Taiwan. Clinically, freeze-dried neurotoxic antivenom (FNAV) produced from horses by Taiwan Centers for Disease Control (CDC) has been the only approved treatment for envenoming for the last few decades. During antivenom production, large numbers of mice are used in the in vivo assay to determine whether the neutralization potency of hyperimmunized equines is satisfactory for large-scale harvesting. However, this in vivo assay is extremely laborious, expensive, and significantly impairs animal welfare. In the pre...
Vaughn SA, Norton NA, Hart KA.Mechanisms resulting in breed predispositions to insulin dysregulation (ID) are poorly characterized. Cortisol antagonizes insulin, and free, biologically active cortisol can be increased in ID. Breed-related differences in serum free cortisol fraction (FCF) could contribute to ID, but FCF has not been quantified in equidae predisposed to ID, such as ponies. To compare FCF and other hypothalamic-pituitary-adrenal (HPA) axis hormones between horses and ponies during health and ID. We hypothesized: (1) FCF is higher in ponies than horses in health, and is higher still in ponies with ID and obes...
Klett D, Combarnous Y.In previous studies, we had shown the synergistic effect of 10 M forskolin (FSK) on the detection threshold of the cyclic AMP response to luteinizing hormones (LH) and chorionic gonadotropins (CG) from various species in the mouse Leydig tumor cell (mLTC) cell line. Independently, we started to study the effect of 10-10 M oxytocin (OXT) also on the cyclic AMP response to LH and CG preparations on these same cells and found an amplifying effect on the luminescence response caused by gonadotropins. The aim was then to explore the effects of 10-10 M OXT on the gonadotropin-induced cAMP response, ...
Honoré ML, Pihl TH, Nielsen LN.Critically ill horses, such as horses with gastrointestinal (GI) disease, often suffer from hemostatic aberrations. Global hemostatic tests examining the initiation of coagulation, clot strength and fibrinolysis, such as the Calibrated Automated Thrombogram (CAT) and plasma-thromboelastography (TEG) have not been evaluated in horses. This study aimed to evaluate CAT and apply plasma-TEG in horses. Test performance of CAT was evaluated on equine platelet poor plasma with intra- and inter-assay variability (CV) and a heparin dilution curve. To examine clinical performance of both tests, group co...
Kahn SK, Cywes-Bentley C, Blodgett GP, Canaday NM, Turner-Garcia CE, Flores-Ahlschwede P, Metcalfe LL, Nevill M, Vinacur M, Sutter PJ, Meyer SC....Hyperimmune plasma raised against β-1→6-poly-N-acetyl glucosamine (PNAG HIP) mediates more opsonophagocytic killing of Rhodococcus equi (R equi) than does R equi hyperimmune plasma (RE HIP) in vitro. The relative efficacy of PNAG HIP and RE HIP to protect foals against R equi pneumonia, however, has not been evaluated. Objective: Transfusion with PNAG HIP will be superior to RE HIP in foals for protection against R equi pneumonia in a randomized, controlled, blinded clinical trial. Methods: Four hundred sixty Quarter Horse and Thoroughbred foals at 5 large breeding farms in the Un...
Soroko M, Howell K, Dudek K, Waliczek A, Micek P, Flaga J.The aim of the study was to determine the utility of maximum eye temperature measured by infrared thermography (IRT) as a stress indicator compared with plasma cortisol concentration in Thoroughbred and Arabian racehorses. The study included thirty racehorses undergoing standard training for racing. Measurements of maximum eye temperature and blood collection for plasma cortisol concentration were carried out before training (BT), and within 5 (5AT) and 120 minutes (120AT) after the end of the each training session in three repetitions, with a monthly interval. Both parameters were elevated at...
Trevisiol S, Moulard Y, Kaabia Z, Delcourt V, Loup B, Garcia P, Boyer S, Dauriac K, Groseille G, Rouger S, Narbe R, Popot MA, Bailly-Chouriberry L.Ciclesonide (CIC) is the first inhaled highly potent corticosteroid that does not cause any cortisol suppression. It has been developed for the treatment of asthma in human and more recently in equine. CIC is the active compound of Aservo® EquiHaler® (Boehringer Ingelheim Vetmedica GmbH), the pre-filled inhaler generating a medicated mist based on Soft Mist™ technology. This prodrug is rapidly converted to desisobutyryl-ciclesonide (des-CIC), the main pharmacologically active compound. Due to its anti-inflammatory properties, CIC is prohibited for use in horse competitions. To set up an ap...
Ishii H, Shibuya M, So YM, Wong JKY, Ho ENM, Kusano K, Sone Y, Kamiya T, Wakuno A, Ito H, Miyata K, Yamada M, Leung GN.IOX4 is a hypoxia-inducible factor prolyl hydroxylase (HIF-PHD) inhibitor, which was developed for the treatment of anemia by exerting hematopoietic effects. The administration of HIF-PHD inhibitors such as IOX4 to horses is strictly prohibited by the International Federation of Horseracing Authorities and the Fédération Équestre Internationale. To the best of our knowledge, this is the first comprehensive metabolic study of IOX4 in horse plasma and urine after a nasoesophageal administration of IOX4 (500 mg/day, 3 days). A total of four metabolites (three mono-hydroxylated IOX4 and one ...
Pesko B, Habershon-Butcher J, Muir T, Gray B, Taylor P, Fenwick S, Hincks P, Scarth J, Paine S.Paracetamol is a widely used, non-opioid analgesic and antipyretic drug. Scientific evidence suggests that it is an effective pain treatment in equine medicine. However, there is very little published information about the pharmacokinetics of the drug in the horse. The aim of the research was to determine the pharmacokinetics of paracetamol in equine plasma and urine to inform treatment of Thoroughbred racehorses. In this multi-dose study, paracetamol was administered orally at 20 mg/kg to six Thoroughbred horses. Pre- and post-administration urine and plasma samples were collected and analys...
Kędzierski W, Sadok I, Kowalik S, Janczarek I, Staniszewska M.Tryptophan (Trp) is an essential amino acid which metabolises via the kynurenine pathway to generate a number of bioactive substances referred to as kynurenines. Among those are 3-hydroxykynurenine (3-HKyn) and quinolinic acid, which are neurotoxic, as well as kynurenic acid (Kyna) and xanthurenic acid (XA), which, similarly to nicotinamide (NAm), show neuroprotective and anti-depressive effects. Routine exercise is known to modulate Trp metabolism in skeletal muscle and is thus believed to reduce the risk of depressive states in humans and laboratory animals. Analogously, it was hypothesised ...
Sgorbini M, Bonelli F, Percacini G, Pasquini A, Rota A.Our aim was to measure the concentrations of derived reactive oxygen metabolite (d-ROMs) and biological antioxidant potential (BAP) of donkey mares and foals at delivery and to verify the protective role of the placenta against fetal oxidative stress. A total of 15 Amiata jennies with a physiological gestation length and delivery were included together with 17 foals (two twin foalings). After delivery, maternal and foal venous blood samples were collected along with blood from the artery. Circulating lactate and plasma d-ROMs and BAP were evaluated. The Wilcoxon test for paired data was applie...
Purnama MTE, Hendrawan D, Wicaksono AP, Fikri F, Purnomo A, Chhetri S. Horses are herd animals that have been domesticated in the last century. In several countries, an overview of risk factors and clinical evaluation in horses with colic has not been well-described. This study aimed to evaluate risk factors and hematological profiles in horses associated with colic in Gresik, East Java, Indonesia. A cross-sectional study was performed during April - October 2019. A total of 115 horses were diagnosed based on physical examination, clinical symptoms, and rectal examination. A questionnaire was asked to the horse-owners to analyze the risk factors while the clin...
Rings LM, Kamr AM, Kinsella HM, Hostnik LD, Swink JM, Burns TA, Christie K, David JB, Toribio RE.The enteroinsular axis (EIA) is an energy regulatory system that modulates insulin secretion through the release of enteroendocrine factors (incretins). Despite the importance of energy homeostasis in the equine neonate, information on the EIA in hospitalized foals is lacking. The goals of this study were to measure serum insulin and plasma incretin (glucose-dependent insulinotropic polypeptide [GIP], glucagon-like peptide-1 [GLP-1] and glucagon-like peptide-2 [GLP-2]) concentrations, to determine the insulin and incretin association, as well as their link to disease severity and outcome in ho...
Hector RC, Rezende ML, Nelson BB, Monnet E.Endotoxaemia causes untoward inflammatory-mediated effects that might be attenuated by dexmedetomidine. Objective: To evaluate the effects of a dexmedetomidine intravenous (IV) infusion on systemic and intestinal haemodynamics and arterial blood gas values in sevoflurane-anaesthetised horses administered Escherichia coli O55:B5 lipopolysaccharides (LPS). Methods: Randomised controlled in vivo experiment. Methods: A total of 13 horses weighing 456 ± 86 kg (mean ± standard deviation) and aged 13.9 ± 9.0 years donated for euthanasia underwent ventral midline celiotomy using sevoflurane...
Tozaki T, Kwak HG, Nakamura K, Takasu M, Ishii H, Ohnuma A, Kikuchi M, Ishige T, Kakoi H, Hirota KI, Kusano K, Hirata M, Nirasawa T, Nagata SI.In human and equestrian sporting events, one method of gene doping is the illegal use of therapeutic oligonucleotides to alter gene expression. In this study, we aimed to identify therapeutic oligonucleotides via sequencing using matrix-assisted laser desorption/ionisation-time-of-flight mass spectrometry (MALDI-TOF MS). As a model of therapeutic oligonucleotides, 22 bp-long phosphorothioated oligonucleotides (PSOs) were used. By using a Clarity OTX kit for extracting short-length oligonucleotides, a spectrum of singly charged PSO with a mean intensity of 6.08 × 10 (standard deviation: ...
Bonilla AG, Causeret L, Torrent-Crosa A.This study investigated the pharmacokinetics of ceftiofur after intravenous regional limb perfusion (IVRLP). Six horses were involved in 3 IVRLP sessions. For each session, operators with varying clinical experience placed the tourniquet. A wide-rubber tourniquet was applied in the antebrachium as 2 g of ceftiofur in a total volume of 100 mL was injected into the cephalic vein. Plasma and metacarpophalangeal synovial fluid samples were obtained to evaluate perfusate leakage and synovial fluid concentrations of ceftiofur over 24 h. Overall, mean plasma concentrations were not significantly diff...
Jiang Z, Haughan J, Moss KL, Stefanovski D, Ortved KF, Robinson MA.Gene therapy is currently prohibited in human and equine athletes and novel analytical methods are needed for its detection. Most in vivo products use non-integrating, recombinant viral vectors derived from adeno-associated virus (AAV) to deliver transgenes into cells, where they are transcribed and translated into functional proteins. Although the majority of wild-type AAV (WTAAV) DNA is removed from recombinant AAV (rAAV) vectors, some sequences are conserved. The goal of this study was to develop a quantitative polymerase chain reaction (QPCR) screening test targeting conserved AAV sequence...
Montgomery JB, Wichtel JJ, Wichtel MG, McNiven MA, McClure JT, Markham F, Horohov DW.The effects of selenium (Se) supplementation and source on equine immune function have not been extensively studied. This study examined the effects of oral Se supplementation and Se source on aspects of innate and adaptive immunity in horses. Fifteen horses were assigned to 1 of 3 groups (5 horses/group): control, inorganic Se (sodium selenite), organic Se (Se yeast). Immune function tests performed included: lymphocyte proliferation in response to mitogen concanavalin A, neutrophil phagocytosis, antibody production after rabies vaccination, relative cytokine gene expression in stimulated lym...
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...
Warren LK, Lawrence LM, Thompson KN.Because exercise fatigue has been associated with the accumulation of lactic acid, factors that influence lactate metabolism during exercise can potentially enhance performance. The objective of this study was to examine the effects of supplemental betaine on eight mature Thoroughbred horses before and after 8 wk of conditioning. The effects of betaine were tested in two cross-over design experiments, allowing each horse to receive both the control and betaine treatments at each fitness level. Ingestion of 80 mg of betaine/kg of BW for 14 d before exercise testing did not alter plasma lactate,...
Higuchi T, Arakawa T, Hashikura S, Inui T, Senba H, Takai S.The effect on foals of prophylactic administration of hyperimmune plasma to prevent R. equi infection was investigated on three farms at which R. equi infection was endemic. Sixteen foals between 10 and 39 days of age were intravenously given 1-21 of hyperimmune plasma. ELISA antibody titres against R. equi were significantly increased and maintained at high levels for over 30 days in most of the recipient foals. The prevalence of R. equi infection was 6.3% (1/16) in the foals that received the immune plasma, and 26.3% (5/19) in the control foals not given the immune plasma on the three farms....
Ho EN, Yiu KC, Wan TS, Stewart BD, Watkins KL.Anti-diabetics such as sulfonylurea and thiazolidinedione derivatives are hypoglycemic drugs used for the treatment of diabetes. However, they can also be used as a stopper in horseracing. This paper describes a convenient method for the separation and simultaneous detection of 10 anti-diabetic drugs (namely glipizide, glibenclamide, glimepiride, gliclazide, tolazamide, tolbutamide, nateglinide, repaglinide, rosiglitazone and pioglitazone) in equine plasma and urine by LC-MS-MS. Methods: The anti-diabetics were isolated from equine plasma and urine by liquid-liquid extraction with 1,2-dichloro...
Shepherd ML, Ponder MA, Burk AO, Milton SC, Swecker WS.The purpose of the present study was to compare digestibility of grass hay, faecal and plasma volatile fatty acid (VFA) concentrations, and faecal bacterial abundance in overweight and moderate-condition mares. Five overweight adult mixed-breed mares and five adult mixed-breed mares in moderate condition were housed individually and limit-fed orchard grass (Dactylis glomerata) hay at 20 g/kg body weight (as fed) daily for 14 d. Forage DM and fibre digestibility were determined using AOAC methods; digestible energy was measured using bomb calorimetry; plasma and faecal VFA concentrations were ...
O'Connor CI, Nielsen BD, Woodward AD, Spooner HS, Ventura BA, Turner KK.Numerous studies suggest that silicon (Si) supplementation is beneficial for mineral metabolism and bone health. Mineral balance studies have not been performed in horses to determine how these supplements affect absorption of other minerals. The purpose of these studies was to investigate the effects of two different Si supplements on mineral absorption and retention in horses. Eight geldings were randomly placed in one of two groups: control (CO) or supplemental Si, which was provided by one of two supplements. The first, sodium aluminium silicate (SA), contains a bioavailable form of Si and...
López C, Alvarez ME, Carmona JU.The aims were (1) to evaluate the bacteriostatic effect of platelet-rich plasma (PRP), platelet-rich gel (PRG), leukocyte-poor plasma (LPP), leukocyte-poor gel (LPG), plasma, and heat-inactivated plasma (IP) on both methicillin-sensitive Staphylococcus aureus (MSSA) and methicillin-resistant Staphylococcus aureus (MRSA) over a period of 24 h; (2) to determine and to compare the concentrations and degradation over time of platelet factor 4 (PF-4), transforming growth factor beta 1 (TGF-β 1), and platelet-derived growth factor isoform BB (PDGF-BB); and (3) to identify any correlations between...
Benbarek H, Deby-Dupont G, Caudron I, Grülke S, Deby C, Lamy M, Serteyn D.In horses, the mechanisms of lipopolysaccharide (LPS) stimulation of isolated neutrophils to produce reactive oxygen species remain unknown. We re-investigated this problem by monitoring the luminol-enhanced chemiluminescence (CL) produced by LPS-stimulated equine neutrophils. The neutrophils were isolated from horse blood by discontinuous density gradient centrifugation (> or = 99% neutrophils; viability > or = 98%). Increasing concentrations of Escherichia coli (E. coli) LPS (from 0.01-10 microg ml(-1)) were used to activate the neutrophils. When LPS was used directly, without another ...
Raidal SL, Andrews FM, Nielsen SG, Trope G.Limited data are available on the relative pharmacokinetics and pharmacodynamics of different omeprazole formulations. Objective: To compare pharmacokinetic and pharmacodynamic effects of a novel omeprazole formulation against a currently registered product. Methods: Masked 2 period, 2 treatment crossover. Methods: Twelve clinically healthy horses were studied over two 6-day treatment periods. Horses were randomly assigned to receive a novel omeprazole paste (Ulcershield: ULS) or a currently registered reference omeprazole product (OMO). Gastric pH was measured continuously for 10 h on the day...
Frank M, Weckman TJ, Wood T, Woods WE, Tai CL, Chang SL, Ewing A, Blake JW, Tobin T.Hordenine is an alkaloid occurring naturally in grains, sprouting barley, and certain grasses. It is occasionally found in post race urine samples, and therefore we investigated its pharmacological actions in the horse. Hordenine (2.0 mg/kg bodyweight [bwt]) was administered by rapid intravenous (iv) injection to 10 horses. Typically, dosed horses showed a flehmen response and defecated within 60 secs. All horses showed substantial respiratory distress. Respiratory rates increased about 250 per cent and heart rates were approximately double that of resting values. All animals broke out in a sw...
Peng C, Yang L, Labens R, Gao Y, Zhu Y, Li J.Equine joint disease including septic arthritis (SA) and osteoarthritis (OA) is a critical cause of equine lameness. Platelet-rich plasma (PRP) is one of the most popular regenerative therapies to treat equine OA, even SA, but the evidence in support of the treatment is conflicting. Objective: The aim of the study was to systematically review the current evidence on PRP products used for SA and OA, as well as the efficacy of PRP products as treatment for OA on the basis of a meta-analysis of the available literature. Methods: Systematic review and meta-analysis. Methods: A systematic search of...
M'Cloud WRC, Guzmán KE, Panek CL, Colbath AC.Platelet-rich plasma (PRP) and mesenchymal stromal or stem cells (MSCs) have been investigated as treatments for equine tendon and ligament injuries, but little consensus exists on the efficacy of these treatments. The study sought to evaluate the efficacy of PRP and MSC treatments by systematic review and meta-analysis. Methods: A systematic review was performed using the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analysis) guidelines. Inclusion criteria required an original, peer-reviewed study where horses were administered MSCs or PRP (or both), and a comparator grou...
Li N, Yu J, Yang F, Shao Y, Wu S, Liu B, Li M, Wang T, Li J, Zeng S.The aim of this study was to evaluate the effects of L-proline on the extender quality of frozen and post-thawed jackass semen. Jackass (n = 6) semen samples were collected and cryopreserved in gradient concentrations (0-80 mM) of L-proline in extenders; post-thawed semen samples were cultured in L-proline medium for 10 hours at 37°C. For cryopreservation experiment I, the motile parameters, mitochondrial membrane potential (MMP), and plasma membrane, acrosome, and chromatin structure integrities of post-thawed semen were assessed. For culture experiment II, additional ROS contents were ana...
Malinowski K, Christensen RA, Hafs HD, Scanes CG.A survey with horses was conducted to determine whether plasma concentrations of triiodothyronine (T3), thyroxine (T4), insulin-like growth factor (IGF)-I and IGF binding proteins (IGFBP) change as horses grow, mature sexually, and age. Jugular blood was sampled from Standardbred fillies and mares at ages 0, 1, 7, and 14 d, at 1, 2, 4, 5, 6, and 9 mo, and at 5 to 8 and 16 to 22 yr (n = 5 to 18). In a second survey, we measured the same variables in eight breeds of horses with markedly different adult body sizes, from Miniatures to Friesians. Plasma T3, T4, and IGF-I were determined by radioimm...
Olsén L, Bondesson U, Broström H, Olsson U, Mazogi B, Sundqvist M, Tjälve H, Ingvast-Larsson C.Horses with insect bite hypersensitivity (IBH) have difficulty in completely avoiding allergens, so effective treatment options are required. A randomised, placebo controlled and double blinded field study was conducted to determine the pharmacokinetics and efficacy in reducing dermatitis of the antihistamine cetirizine given orally at 0.4 mg/kg twice daily for 3 weeks. The influence of protection blankets and stabling were also investigated. The estimated maximum plasma concentration (C(max)) and trough plasma concentration of cetirizine were 135 ng/mL and 18 ng/mL, respectively. There was no...
May ML, Nolen-Walston RD, Utter ME, Boston RC.During hospitalization, horses typically undergo frequent blood sampling for diagnostic testing and monitoring. The need for numerous samples in hospitalized horses makes acquisition from an intravenous catheter (IVC) both convenient and less stressful to the patient. Objective: We hypothesized that there would be no significant difference in the plasma chemistry and CBC variables from blood samples obtained from a jugular catheter as compared with direct jugular venipuncture. Methods: Fifty adult hospitalized horses; 25 receiving constant rate crystalloid therapy, and 25 receiving low volume ...
Nagel C, Trenk L, Aurich J, Wulf M, Aurich C.In this study, peripartum changes in complete blood count, plasma electrolyte concentrations, blood pressure, heart rate, and heart rate variability (HRV) were determined in pregnant Warmblood mares (n = 10). Blood was collected from Days 245 to 330 of gestation (phase A), 2Days 3 to 1 before foaling (phase B), repeatedly within 12 hours after foaling (phase C), and on Days 1 to 3 postpartum (phase D). On the same days as blood collection, blood pressure and cardiac beat-to-beat intervals were measured and time domain HRV variables were calculated. Blood pressure decreased during the past 3...
Riggs LM, Franck T, Moore JN, Krunkosky TM, Hurley DJ, Peroni JF, de la Rebière G, Serteyn DA.To compare measurements of myeloperoxidase (MPO) in plasma, laminar tissues, and skin obtained from control horses and horses given black walnut heartwood extract (BWHE). Methods: 22 healthy 5- to 15-year-old horses. Methods: Horses were randomly assigned to 4 groups as follows: a control group given water (n = 5) and 3 experimental groups given BWHE (17) via nasogastric intubation. Experimental groups consisted of 5, 6, and 6 horses that received BWHE and were euthanatized at 1.5, 3, and 12 hours after intubation, respectively. Control horses were euthanatized at 12 hours after intubation. Pl...
Zabrecky KA, Slovis NM, Constable PD, Taylor SD.Accurate diagnostic markers for sepsis in neonatal foals are needed. Plasma C-reactive protein concentration (p[CRP]) and haptoglobin concentration (p[Hp]) are well-established biomarkers of infection in humans, but studies are lacking in foals. Objective: p[CRP]) and p[Hp] are increased in septic foals compared to sick nonseptic and healthy control foals, and are predictive of survival. Methods: Eighty critically ill foals (40 septic, 40 sick nonseptic) and 39 healthy control foals <1 week of age. Methods: Multicenter, prospective observational clinical study. Venous blood was collected at a...
Wilson MG, Nicholson WE, Holscher MA, Sherrell BJ, Mount CD, Orth DN.Using RIAs for six regions within proopiolipomelanocortin (proOLMC), gel filtration, and electrophoresis, we studied pituitary peptides in a normal horse and one with Cushing's disease caused by a pars intermedia adenoma. Almost all immunoreactive (IR) ACTH (78%) was 4,500 mol wt (4.5K) ACTH in normal pars distalis, but it was almost 100% corticotropin-like intermediate lobe peptide (CLIP) in normal pars intermedia. alpha MSH and beta MSH were found mainly in pars intermedia: equal concentrations of the beta MSH precursors, beta-lipotropin (beta LPH) and gamma LPH, were found in pars distalis....
Navarro M, Monreal L, Segura D, Armengou L, Añor S.The purpose of this study was to compare traditional and quantitative approaches in analysis of the acid-base and electrolyte imbalances in horses with acute gastrointestinal disorders. Venous blood samples were collected from 115 colic horses, and from 45 control animals. Horses with colic were grouped according to the clinical diagnosis into 4 categories: obstructive, ischemic, inflammatory, and diarrheic problems. Plasma electrolytes, total protein, albumin, pH, pCO2, tCO2, HCO3-, base excess, anion gap, measured strong ion difference (SIDm), nonvolatile weak buffers (A(tot)), and strong io...
Hoffman RM, Kronfeld DS, Holland JL, Greiwe-Crandell KM.The stress response of foals during weaning was examined in terms of a behavioral protocol and the responses of plasma ascorbate, serum cortisol, and the serum cortisol response to an ACTH challenge. The experimental plan was a 2 x 2 factorial of two preweaning diets and two stall weaning methods. Dietary groups included foals raised on pasture supplemented with hay and a pelleted concentrate (PHC) and foals raised on pasture supplemented with hay only (PH). Stall weaning methods included foals placed in stalls singly or in pairs. Sex influences were also examined. The foals exhibited characte...
Thomas LA, Brown SA.The relationship between colloid osmotic pressure (COP) and protein concentration was investigated for purified proteins and plasma samples obtained from cattle, horses, dogs, and cats. At equivalent concentrations, bovine albumin exerted a COP that exceeded that of gamma-globulins by a mean factor of 4.4. Similar relationships between COP and protein were observed in the other species. Consequently, for a given total protein concentration, COP was dependent on the albumin/gamma-globulins ratio. A commonly used nomogram for estimating COP from protein concentration, the Landis-Pappenheimer equ...
Wagner B, Ainsworth DM, Freer H.Soluble CD14 (sCD14) binds bacterial lipopolysaccharide (LPS) and acts as an anti-inflammatory LPS-inhibitor in vivo. In humans, sCD14 is one of the soluble biomarkers used for various inflammatory diseases and conditions, however, sCD14 assays have not yet been evaluated in horses. Here, we developed and optimized a bead-based assay for the quantification of sCD14 in horses. The assay was then used to determine native sCD14 concentrations in serum from healthy and septic foals, in the colostrum of healthy mares and in plasma from adult horses with recurrent airway obstruction (RAO) and contro...
Ohmura H, Nukada T, Mizuno Y, Yamaya Y, Nakayama T, Amada A.To determine a safe and efficacious dose of flecainide acetate for treating equine atrial fibrillation (Af), the safe dosage level was determined by injecting 1, 2, or 3 mg/kg i.v. of 1% flecainide acetate solution at a rate of 0.2 mg/kg/min to five clinically healthy horses. Clinical signs and the ECG were monitored (HR, PR, QRS, and QT intervals) and blood was taken to measure the plasma flecainide concentration pre- and post-administration. No abnormal signs were observed in the 1- or 2-mg/kg groups, while agitation was observed in three of five horses in the 3-mg/kg group. The QRS, and QT ...
Pinto N, Schumacher J, Taintor J, Degraves F, Duran S, Boothe D.No studies have determined the pharmacokinetics of low-dose amikacin in the mature horse. Objective: To determine if a single i.v. dose of amikacin (10 mg/kg bwt) will reach therapeutic concentrations in plasma, synovial, peritoneal and interstitial fluid of mature horses (n=6). Methods: Drug concentrations of amikacin were measured across time in mature horses (n=6); plasma, synovial, peritoneal and interstitial fluid were collected after a single i.v. dose of amikacin (10 mg/kg bwt). Results: The mean±s.d. of selected parameters were: extrapolated plasma concentration of amikacin at time ze...
Wessely-Szponder J, Bełkot Z, Bobowiec R, Kosior-Korzecka U, Wójcik M.Deleterious response to road transport is an important problem in equine practice. It determines different physiological, immunological and metabolic changes which lead to increased susceptibility to several disorders such as pneumonia, diarrhea, colics, laminitis, injuries and rhabdomyolisis. The aim of our study was to look for possible relationships between transportation of female young and older horses over a long and short distance and an inflammatory state reflected by an increase of acute phase protein concentration, oxidative stress and muscle injury. The study was conducted on 24 col...
Powis G, Snow DH.There are now several examples showing that experimentally induced changes in hepatic blood flow can have a marked effect upon the elimination of certain high clearance drugs. Changes in hepatic blood flow produced by exercise might therefore be expected to influence the clearance of these drugs. There was an increase of up to 100%, compound to control values, in the plasma levels of propranolol in horses given either d- or dl-propranolol, 0.2 mg/kg b.wt., and then subjected to sustained exercise for 30 minutes. There was, however, no similar increase with exercise in the plasma levels of anti...
