Topic:Plasma
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.
Role of exercise and ascorbate on plasma antioxidant capacity in thoroughbred race horses. During exercise, the oxygen consumption and the production of free radicals increase and can lead to oxidative stress with a deleterious effect on cellular structures involved in physical activity. To evaluate the oxidative stress produced by exercise and the role of ascorbate as an antioxidant, venous blood samples were obtained from 44 thoroughbred racehorses, before and after a 1000+/-200-m race at maximum velocity. Fourteen of these horses were treated intravenously with 5 g of ascorbate before running. Antioxidant capacity (PAOC), endogenous and exogenous ascorbate concentration, total an...
Effect of ration and exercise on plasma creatine kinase activity and lactate concentration in Thoroughbred horses with recurrent exertional rhabdomyolysis. To determine the effects of 3 rations (low grain, fat, high grain) on plasma creatine kinase (CK) activity and lactate concentration in Thoroughbred horses with recurrent exertional rhabdomyolysis (RER). Methods: 5 Thoroughbreds with RER and 3 healthy Thoroughbreds (control horses). Methods: Rations were formulated to meet (low-grain and fat rations) or exceed (high-grain ration) daily energy requirements. Each ration was fed to horses in a crossover design for 3 weeks. Horses were exercised on a treadmill Monday through Friday; maximum speed on Monday and Friday was 11 m/s (6% slope), on Tues...
Quantification of phenytoin and its metabolites in equine plasma and urine using high-performance liquid chromatography. A reliable and sensitive method for the extraction and quantification of phenytoin (5,5'-diphenylhydantoin), its major metabolite, 5-(p-hydroxyphenyl)-5-phenylhydantoin (p-HPPH) and minor metabolite, 5-(m-hydroxyphenyl)-5-phenylhydantoin (m-HPPH) in horse urine and plasma is described. The method involves the use of solid-phase extraction (SPE), liquid-liquid extraction (LLE), enzyme hydrolysis (EH) and high-performance liquid chromatography (HPLC). The minor metabolite, 5-(m-hydroxyphenyl)-5-phenylhydantoin (m-HPPH) was not present in a reliably quantifiable concentration in all samples. The ...
Effect of dose and day of treatment on uterine response to oxytocin in mares. To determine the effect of dose and day of oxytocin treatment on intrauterine pressure, 6 normal mares were treated with 10 or 25 IU oxytocin 2 days before ovulation, on the day of ovulation and 2 days after ovulation. Intrauterine pressure (IUP) was measured using micro-tip-catheters (one placed intrauterine, a second and third serving as reference sensors in the vagina and external to the mare) and transmitted by telemetry for 30 min to establish a baseline before saline was administered, iv, and for an additional 30 min after saline administration. Oxytocin was then given, iv, and IUP was r...
Dehydration, stress, and water consumption of horses during long-distance commercial transport. The aim of this study was to characterize progressive dehydration, stress responses, and water consumption patterns of horses transported long distances in hot weather and to estimate recovery time after 30 h of transport. Thirty adult mares and geldings were deprived of access to feed and water for 6 h, blocked by age, sex, breed, and body condition score, and assigned to one of the following treatments: penned, offered water (Penned/Watered, n = 5); penned, no water (Penned, n = 5); transported, offered water (Transported/Watered, two groups of n = 5); or transported, no water (Transported, ...
Distribution of immunoglobulin isotypes and subisotypes in equine guttural pouch (auditory tube diverticulum). To clarify the functions of the equine guttural pouch, the distribution of various immunoglobulin isotypes and subisotypes in the guttural pouch mucosa were examined in healthy horses. IgGa was present in the mucosa of guttural pouch, mucosal lymph nodules and submucosal lymph nodules. IgM was scattered in the mucosal lymph nodules and in the germinal centers of the submucosal lymph nodules. IgGc was recognized only in the submucosal lymph nodules. These immunoglobulin isotypes and subisotypes were found in lymphocytes and plasma cells. On the other hand, IgA was detected in glandular epitheli...
Hemithyroidectomy in a horse with confirmed hyperthyroidism. A 23-year-old Quarter Horse gelding was admitted to the hospital because of cachexia and hyperactive behavior of 1 year's duration. At admission the horse was severely emaciated, tachycardic with a grade V/VI diastolic murmur, pyrexic, polydipsic, enophthalmic, and alopecic. The right lobe of the thyroid gland was noticeably larger than typical. The horse was also hyperexcitable and had a ravenous appetite. A presumptive diagnosis of hyperthyroidism was made on the basis of clinical signs and high plasma thyroid hormone concentrations. Confirmation of the diagnosis was made on the basis of res...
Measurement of plasma colloid osmotic pressure in normal thoroughbred neonatal foals. A normal plasma colloid osmotic pressure (COP) interval was established for foals and compared to values for adult horses. Plasma samples were obtained from 38 Thoroughbred foals that had normal findings on postfoaling examination and 10 healthy Thoroughbred adult horses. Samples were analyzed using a commercially available colloid osmometer. Fifty samples were obtained from 38 foals. Twelve foals had 2 samples taken, 1 during the 1st 24 hours of life and the 2nd between 24 and 72 hours of life. For foals with 2 samples, only 1 randomly selected value was used in group analysis. Total plasma p...
Measurement of 19-nortestosterone and its esters in equine plasma by high-performance liquid chromatography with tandem mass spectrometry. A high-performance liquid chromatographic-tandem mass spectrometric (HPLC/MS/MS) method for the determination of 19-nortestosterone and its esters (cyclopentanepropionate, phenylpropionate, and decanoate) in equine plasma is achieved using an atmospheric pressure chemical ionization (APCI) interface in selected reaction monitoring (SRM) mode. The two internal standards used were 16,16, 17-(2)H(3)-19-nortestosterone for 19-nortestosterone and methenolone acetate for its esters. The steroids studied were extracted from plasma samples with a mixture of diethyl ether/n-hexane (9:1, v/v). The quant...
Effects of prior feeding on pharmacokinetics and estimated bioavailability after oral administration of a single dose of microencapsulated erythromycin base in healthy foals. To determine effects of prior feeding on pharmacokinetics and estimated bioavailability of orally administered microencapsulated erythromycin base (MEB) in healthy foals. Methods: 6 healthy foals, 3 to 5 months old. Methods: Foals were given 2 doses of MEB (25 mg/kg of body weight, PO). One dose was administered after food was withheld overnight, and the other was administered after foals had consumed hay. The study used a crossover design with a 2-week period between doses. Blood was collected via a jugular vein prior to and at specific times after drug administration. Concentrations of eryth...
Investigation of the susceptibility of equine autonomic neuronal cell lines, clonally derived from the same paravertebral ganglion, to toxic plasma from equine dysautonomia (grass sickness) cases. In the autonomic nervous system (ANS) of equine grass sickness (GS) cases, some neurones show abnormal changes while neighbouring neurones are unaffected. To test whether noradrenergic neurones showed variable susceptibility to the GS toxin in culture, clonally-derived populations isolated from the same fetal thoracic sympathetic chain ganglion were challenged with plasma from GS cases previously shown to induce ANS damage when injected into normal horses. During the early stages of exposure to toxic plasma, cells within a clonal population showed variable susceptibility ranging from no obviou...
Effects of exercise intensity and duration on plasma beta-endorphin concentrations in horses. To determine the relationship between plasma beta-endorphin (EN) concentrations and exercise intensity and duration in horses. Methods: 8 mares with a mean age of 6 years (range, 3 to 13 years) and mean body weight of 450 kg. Methods: Horses were exercised for 20 minutes at 60% of maximal oxygen consumption (VO2max) and to fatigue at 95% V02max. Plasma EN concentrations were determined before exercise, after a 10-minute warmup period, after 5, 10, 15, and 20 minutes at 60% VO2max or at the point of fatigue (95% VO2max), and at regular intervals after exercise. Glucose concentrations were deter...
Pharmacokinetics of erythromycin estolate and erythromycin phosphate after intragastric administration to healthy foals. To determine pharmacokinetics and plasma concentrations of erythromycin and related compounds after intragastric administration of erythromycin phosphate and erythromycin estolate to healthy foals. Methods: 11 healthy 2- to 6-month-old foals. Methods: Food was withheld from foals overnight before intragastric administration of erythromycin estolate (25 mg/kg of body weight; n = 8) and erythromycin phosphate (25 mg/kg; 7). Four foals received both drugs with 2 weeks between treatments. Plasma erythromycin concentrations were determined at various times after drug administration by use of high-p...
Safe and efficacious dosage of flecainide acetate for treating equine atrial fibrillation. 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 ...
Total body water and ECFV measured using bioelectrical impedance analysis and indicator dilution in horses. The purposes of this study were 1) to determine the compartmentation of body water in horses by using indicator dilution techniques and 2) to simultaneously measure bioelectrical impedance to current flow at impulse current frequencies of 5 and 200 kHz to formulate predictive equations that could be used to estimate total body water (TBW), extracellular fluid volume (ECFV), and intracellular fluid volume (ICFV). Eight horses and ponies weighing from 214 to 636 kg had catheters placed into the left and right jugular veins. Deuterium oxide, sodium thiocyanate, and Evans blue were infused for the...
Plasma cortisol and ACTH concentrations in the warmblood horse in response to a standardized treadmill exercise test as physiological markers for evaluation of training status. Reliable physiological markers for performance evaluation in sport horses are missing. To determine the diagnostic value of plasma ACTH and cortisol measurements in the warmblood horse, 10 initially 3-yr-old geldings of the Hannovarian breed were either exposed to a training schedule or served as controls. During experimental Phase 1, horses were group-housed, and half of the horses were trained for 20 wk on a high-speed treadmill. During Phase 2, groups were switched and one group was trained for 10 wk as during Phase 1, whereas the control group was confined to boxes. During Phase 3 horses w...
Lipid metabolism in equines fed a fat-rich diet. The hypothesis tested was that dietary fat, when compared with an isoenergetic amount of non-structural carbohydrates, stimulates lipolysis in adipose tissue and also stimulates the fatty-acid oxidative capacity in skeletal muscle from horses. Six adult horses were fed a high-fat, glucose or starch containing diet according to a 3 x 3 Latin square design with feeding periods of three weeks. The diets were formulated so that the intake of soybean oil versus either glucose or corn starch were the only variables. In accordance with previous work, whole plasma triacylglycerol (TAG) concentration d...
Carbohydrate supplementation of horses during endurance exercise: comparison of fructose and glucose. To delay the onset of fatigue, endurance horses are often fed at rest stops during races. The resulting increase in blood insulin may adversely inhibit lipolysis. In humans, ingestion of fructose produces a smaller insulin rise than glucose. This study compared glucose and fructose as carbohydrate supplements for endurance horses. Three Arabian geldings were given 300 g of fructose (F), glucose (G) or 50% glucose: 50% fructose (GF), in 1.5 L water, by stomach tube. In the Resting Test, carbohydrate was administered at rest. Following treatment, blood samples were taken every 30 min for 8 h, an...
Pharmacokinetics of enrofloxacin administered intravenously and orally to foals. 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...
Extramedullary plasmacytoma in a horse with ptyalism and dysphagia. A Clydesdale mare was examined for weight loss, inappetence, ptyalism, and dysphagia. The main abnormality revealed by serum biochemistry was a marked hyperglobulinemia, and protein electrophoresis revealed a monoclonal gammopathy in the gamma region. The urine was positive for Bence Jones proteins. These findings suggested a plasma cell tumor. The neoplasm could not be located with extensive antemortem examination. At postmortem, neoplastic cells morphologically compatible with plasma cells and positive for equine IgG with imunoperoxidase staining infiltrated the pericardium, mediastinal stro...
Comparative studies on the cysteine proteinase inhibitory capacity of mammalian blood. The inhibition of cysteine proteinase (papain) by human, bovine, horse, rabbit, guinea pig, rat, hamster, and mouse plasma, and pig, sheep, goat, and dog sera was investigated. The rat and mouse plasma and the pig serum showed such high inhibitory capacity as 813, 380, and 508%, respectively, of the human plasma. On the other hand, the horse, guinea pig, and rabbit plasma indicated 36, 40, and 54%, respectively, of the human plasma. A cysteine proteinase inhibitor (s) was separated from alpha-macroglobulin by Sephacryl S-300, and the inhibitory activity of all of the mammalian plasma/sera exce...
Quantitative analysis of acid-base balance in show jumpers before and after exercise. The acid-base status of venous blood was studied in 17 show jumpers before and after exercise using both a traditional and a quantitative approach. Partial pressure of carbon dioxide (PCO(2)), pH, haemoglobin, and plasma concentrations of sodium (Na(+)), chloride (Cl(-)), potasium (K(+)), ionized calcium (Ca(2+)), total proteins, albumin, lactate and phosphorus were measured in jugular venous blood samples obtained before and immediately after finishing a show jumping competition. Bicarbonate, anion gap and globulin concentration were calculated from the measured parameters. 'Quantitative anal...
Application of the restricted-access precolumn packing material alkyl-diol silica in a column-switching system for the determination of ketoprofen enantiomers in horse plasma. The group of LiChrospher ADS (alkyl-diol silica) sorbents that make part of a unique family of restricted-access materials, have been developed as special packings for precolumns used in the LC-integrated sample processing of biofluids. The advantage of these sorbents lies in the direct injection of untreated biological fluids, that is without sample clean-up, the elimination of the protein matrix with a quantitative recovery together with an on-column enrichment. The present method is based on previous work applying UV detection at 260 nm for ketoprofen determinations. Plasma samples introduc...
Relationship between ultrasonic characteristics of the corpus luteum, plasma progesterone concentration and early pregnancy diagnosis in Friesian mares. The purpose of the present study was to evaluate the change in cross-sectional area of the early corpus luteum (CL) and progesterone production in relation to subsequent pregnancy diagnosis. The cross-sectional area of the CL of 75 Friesian brood mares was measured by ultrasonography on Day 1 or 2 and Day 8 or 9 after ovulation. The change in cross-sectional area was expressed in a volume ratio. Plasma progesterone concentrations were measured on Days 8 to 9, and ultrasonography to determine pregnancy status was carried out on Day 17. The data obtained were analyzed by using a multiple logisti...
Dynamics of prostaglandin secretion, intrauterine fluid and uterine clearance in reproductively normal mares and mares with delayed uterine clearance. 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...
Effect of passive immunization against inhibin on FSH secretion, folliculogenesis and ovulation rate during the follicular phase of the estrous cycle in mares. Physiological roles of inhibin in mares were investigated by means of passive immunization using an antiserum to inhibin that had been raised in a castrated goat. Eight mares were given an intravenous injection of either 100 mL (n = 4) or 200 mL (n = 4) of inhibin antiserum 4 d after a single intramuscular injection of PGF2 alpha on Day 8 after ovulation, 4 control mares were treated with 100 mL castrated goat serum in the same manner. Jugular vein blood samples were collected after treatment with the serum until 192 h post treatment. Follicular growth and ovulations were monitored by ultrasou...
Heat acclimation improves regulation of plasma volume and plasma Na(+) content during exercise in horses. This study determined the plasma volume (PV) and ion responses to heat acclimation and exercise in six trained Thoroughbred horses during 21 days of exposure to heat and humidity (33 degrees C, 83% relative humidity) for 4 h/day. During the 2nd h on days 0, 3, 7, 14, and 21, horses performed a standardized treadmill test, running at 50% of peak O(2) uptake until pulmonary artery temperature reached 41.5 degrees C. Heat acclimation resulted in an increase in PV from 21.3 +/- 1.1 liters on day 0 to 24.3 +/- 1.0 liters on day 14, returning to 22.6 +/- 0.9 liters on day 21. The corresponding total...
Determination of the lactate breakpoint during incremental exercise in horses adapted to dietary corn oil. To determine lactate breakpoint of horses and test for effects of training and dietary supplementation with corn oil on that breakpoint. Methods: 7 healthy Arabian horses. Methods: Horses received a control diet (n = 4) or a diet supplemented with 10% corn oil (4). A training program, which comprised two 5-week conditioning periods with 1 week of rest, was initiated. Submaximal incremental exercise tests (IET) were conducted before the first and after both conditioning periods. Blood samples for determination of blood lactate and plasma glucose concentrations were collected 1 minute before IET...
Urinary concentration of corticoids in ponies with hyperlipoproteinaemia or hyperadrenocorticism. The urinary corticoid:creatinine (c:c) ratio was determined in ten pony mares suffering from hyperlipoproteinaemia. The mean (+/- sd) urinary c:c ratio of these ten ponies (47 +/- 31 x 10(-6)) was not significantly different from that of twelve pony mares with a pituitary pars intermedia adenoma (31 +/- 18 x 10(-6). The correlation between the urinary concentration of corticoids and plasma total lipids, and the correlation between the urinary c:c ratio and plasma total lipids in ponies with hyperlipoproteinaemia were not significant (P > 0.05; r = 0.53 and r = 0.008, respectively). Preliminary...