Omneity® Pellets
All-In-One Vitamin & Mineral Pellet
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.
Three-year study on trace mineral concentration in the blood plasma of Shetland pony mares. Changes in some trace minerals concentrations (calcium, inorganic phosphorus, magnesium, zinc, iron, copper, sodium and potassium) in blood plasma were investigated during a three-year period in Shetland pony mares. Blood plasma mineral concentrations were determined by the atomic absorption method and colorimetric method. The three-year averages were in micrograms/ml; Na 4630 +/- 168; K 277 +/- 3.8; Ca 171 +/- 3.8; P 31.5 +/- 0.74; Fe 1.92 +/- 0.14; Zn 1.07 +/- 0.04 and Cu 1.06 +/- 0.02. Two trace minerals (magnesium in inorganic phosphorus) showed only long-term tendency changes--upward or d...
Physiological stimuli of thirst and drinking patterns in ponies. The stimuli that elicit thirst were studied in four ponies. Nineteen hours of water deprivation produced an increase in plasma protein from 67 +/- 0.1 g/litre to 72 +/- 2 g/litre, a mean (+/- se) increase in plasma sodium from 139 +/- 3 to 145 +/- 2 mmol/litre and an increase in plasma osmolality from 297 +/- 1 to 306 +/- 2 mosmol/litre. Undeprived ponies drank 1.5 +/- 0.9 kg/30 mins; 19 h deprived ponies drank 10.2 +/- 2.5 kg/30 mins and corrected the deficits in plasma protein, plasma sodium and plasma osmolality as well as compensating for the water they would have drunk during the deprivat...
[Chronopharmacokinetics of phenylbutazone in the horse. Application to antidoping control]. Chronopharmacokinetics of intravenous phenylbutazone in the horse was studied with the aim of antidoping control. Among parameters studied, the single one which seemed to depend on circadian rhythm was the elapsed time between the injection and the plasmatic peak. There was no relationship between the injection time and the both parameters: half-life and time required to reach the forensic level of 4 micrograms/ml. This later, and oxyphenbutazone/phenylbutazone ratio, should depend on individual factors. Therefore, the injection time should not be a main parameter for the phenylbutazone evalua...
A sensitive liquid chromatographic procedure for the analysis of camphor in equine urine and plasma. A sensitive method was required to analyze low levels of camphor in equine urine and plasma. Camphorated oil (20% w/w camphor) was administered topically (6 g) and intratracheally (1 g) to standardbred mares. The drug was extracted from urine and plasma by diethyl ether and analyzed as its 2,4-dinitrophenylhydrazone derivative by reverse phase HPLC with UV detection. The UV detector was set at 368.5 nm and the samples were eluted from the C18 column by 82% acetonitrile in water. The detection limit achieved was about 10 ng/mL urine and about 20 ng/mL plasma. After topical administration, only ...
Qualitative detection of corticosteroids in equine biological fluids and the comparison of relative dexamethasone metabolite/dexamethasone concentration in equine urine by micro-liquid chromatography-mass spectrometry. Several important corticosteroids were qualitatively determined in the plasma and urine of horses by micro-liquid chromatography-mass spectrometry (micro-LC-MS). The sensitivity and specificity of micro-LC-MS are demonstrated as is the ability of micro-LC-MS to deal with endogenous interferences. In turn, the relative amount of dexamethasone and its major unconjugated metabolite were determined in equine urine by micro-LC-MS; the conclusions drawn are reported.
Pharmacokinetics and bioavailability of theophylline in horses. The pharmacokinetics and bioavailability of theophylline in horses were investigated following both intravenous and intragastric administration of aminophylline solutions at doses corresponding to 15 and 10 mg/kg theophylline base. A rapid distributive phase with a half-life of approximately 15-30 min was followed by a slower elimination half-life averaging 15-17 h. The apparent volume of distribution averaged 850-900 ml/kg. Theophylline, administered as aminophylline solution, was both rapidly and completely absorbed from the equine digestive tract. Based on the bioavailability and dispositio...
Population distributions of phenylbutazone and oxyphenbutazone after oral and i.v. dosing in horses. Experiments to determine the residual plasma concentrations of phenylbutazone and its metabolites found in horses racing on a 'no-race day medication' or 24-h rule were carried out. One dosing schedule (oral-i.v.) consisted of 8.8 mg/kg (4 g/1000 lbs) orally for 3 days, followed by 4.4 mg/kg (2 g/1000 lbs) intravenously on day 4. A second schedule consisted of 4.4 mg/kg i.v. for 4 days. The experiments were carried out in Thoroughbred and Standardbred horses at pasture, half-bred horses at pasture, and in Thoroughbred horses in training. After administering the i.v. schedule for 4 days to Thor...
[Plasma fibrinogen as a parameter of the presence and severity of inflammation in horses and cattle]. Determination of the plasma fibrinogen concentration was found to be particularly useful in detecting inflammatory diseases. The highest levels were observed in inflammatory lesions of serous surfaces and in endocarditis. Plasma fibrinogen levels correlated with the severity of the disease: levels of 1,000 mg per 100 ml or more reflected a prognosis ranging from poor to bad.
Pharmacologic and pharmacokinetic properties of methocarbamol in the horse. The hemodynamic, respiratory, and behavioral effects, as well as the pharmacokinetic properties of methocarbamol, were determined in horses. Heart rate, cardiac output, arterial and venous blood pressures, respiratory rate, and arterial blood gases did not change after IV methocarbamol (4.4, 8.8, 17.6 mg/kg) administration. There were no signs of behavior modification or ataxia observed. Analysis of plasma concentration time data indicated that the disposition of methocarbamol may be dose-dependent. Clearance and steady-state volume of distribution decreased as the dose increased. Plasma conce...
Equine plasma banking: collection by exsanguination. A procedure was developed for the collection, preparation, storage, and administration of equine plasma. The technique involved exsanguination of anesthetized donor horses via carotid artery catheterization with a large-bore cannula. Blood was collected into plastic bags, allowed to settle by gravity, then transferred into storage bags and frozen. These were quickly thawed when needed.
Plasma mepivacaine concentrations after caudal epidural and subarachnoid injection in the horse: comparative study. The venous plasma concentrations of mepivacaine were determined in 7 adult mares (420 +/- 17.1 kg) given an injection of a 2% solution of the hydrochloride at either the sacral (S2-3 to S5-C1) epidural space or the midsacral (S2-3) subarachnoid space. An average dose of 91.4 +/- 15.7 mg (4.6 +/- 0.8 ml) was needed to produce caudal epidural analgesia (CEA) and 26.7 +/- 5.4 mg (1.3 +/- 0.3 ml) to produce caudal subarachnoid analgesia (CSA). Maximal caudal analgesia extended from spinal cord segments S-1 to coccyx during CEA and CSA. The onset of analgesia as measured by response to superficial ...
The starch digestion test in the horse. Variable results were obtained when the starch digestion test was carried out on a suspected case of malassimilation in a horse. In order to re-evaluate this test, 15 starch digestion tests were carried out using 4 horses. Results showed a marked variation in the increase in plasma glucose levels between individual horses and especially between poor and good condition horses when the dose of starch was based on body mass. Results also suggest that a fixed dose of starch may give more consistent results.
Potassium concentration in equine red blood cells: normal values and correlation with potassium levels in plasma. The concentration of potassium in plasma and in red blood cells was determined in 948 horses. The coefficient of correlation between the two parameters was low. In 436 of these horses, which were clinically healthy, the red blood cell potassium (RBCK+) levels did not fit within a normal distribution curve, but a bimodal distribution was observed with a section point at 90 mmol/litre. In 90 per cent of these normal horses, mean RBCK+ content was 97.5 mmol/litre. In the remaining 10 per cent, mean RBCK+ concentration was 93.8 mmol/litre. A subdivision into a 'low potassium group' and a 'high pot...
Dexamethasone and prednisolone in the horse: pharmacokinetics and action on the adrenal gland. Pharmacokinetics of dexamethasone and prednisolone were studied in 6 horses given dexamethasone alcohol (IV or IM) or dexamethasone 21-isonicotinate as a solution IV or IM (50 micrograms/kg of body weight), prednisolone 21-sodium succinate IV or IM (0.6 mg/kg of body weight), or prednisolone acetate IM (0.6 mg/kg of body weight). Plasma concentrations were determined using a high-performance liquid chromatographic method. After dexamethasone alcohol (IV) or dexamethasone 21-isonicotinate (IV), the half-life of elimination was similar (53 minutes) for both formulations. After dexamethasone (alc...
Effects of furosemide on the plasma and urinary concentrations and the excretion of fentanyl: model for the study of drug interaction in the horse. The effects of furosemide (0.55 mg/kg IV) on the plasma and urinary fentanyl (PFE UFE) concentrations were studied during steady-state conditions. The PFE during the steady-state period was 0.31 +/- 0.027 ng/ml, with no significant changes occurring, even though the rate of excretion of fentanyl (EX) increased during the 1st hour from 112.0 +/- 21.6 to 534.5 +/- 82.9 ng/minute. The EX returned to control levels within 3 hours, as did the UFE. The injection of furosemide increased glomerular filtration rate from 1.97 +/- 0.21 to 3.81 +/- 0.75 ml/kg/min. The fractional reabsorption decreased fro...
Studies on equine prematurity 4: Effect of salt and water loss on the renin-angiotensin-aldosterone system in the newborn foal. Plasma renin substrate concentration was measured in 18, four-day-old pony foals after the administration of the natriuretic agent frusemide. Thirteen foals had been delivered spontaneously; labour had been induced in the remaining five mares. Plasma aldosterone concentration was measured in 12 of the spontaneously delivered foals. Renin substrate concentration had risen sharply within 15 mins (P less than 0.005) and peaked at 1 h. The response was consistently greater in the induced foals. Serum sodium concentration fell rapidly in the induced foals (P less than 0.002 by 60 mins) but was bett...
Hypothyroidism in the foal. Hypothyroidism in the foal occurs as two entities because of the separate actions of thyroid hormones in regulation of metabolic rate and in cell differentiation. The hypometabolic state which results in inadequate thermogenesis and lethargy, occurs concurrently with a period when thyroid hormone secretion is inadequate. Also the severity of the concurrent symptoms is related to the degree of hormone inadequacy as measured by plasma concentrations of free T4 and T3. By contrast, the developmental lesions caused by hypothyroidism are often observed during periods when plasma thyroid hormone con...
Concentration increase of unbound testosterone in plasma of the mare throughout pregnancy. Blood testosterone levels were measured by RIA and gas chromatography-mass spectrometry in the pregnant mare. They were found to increase from the very beginning of pregnancy, reaching peak values 10 times higher than the basal values at the seventh month and then to return to basal values by the week after parturition. Testosterone binding by plasma proteins was investigated in nonpregnant and pregnant mares throughout gestation. Equilibrium dialysis and gel equilibration methods did not reveal any blood specific testosterone-binding activity at any gestational stage. Hence, blood testosteron...
Influence of phenylbutazone on eicosanoid levels in equine acute inflammatory exudate. In a two part cross-over experiment, acute inflammatory exudates were induced in 7 ponies by subcutaneous implantation of 3 sterile carrageenin-soaked polyester sponge strips. Treatment comprised a single therapeutic geenin-soaked polyester sponge strips. Treatment comprised a single therapeutic dose of 4.4 mg/kg phenylbutazone (PBZ) administered intravenously at the time of sponge implantation. Exudates were harvested at 6, 12 and 24 hours and examined for leukocyte and erythrocyte numbers using the improved Neubauer technique; for eicosanoids by radioimmunoassay and by high performance liqui...
Pharmacokinetics of 4-aminopyridine in horses. The pharmacokinetics of 4-aminopyridine (4-AP), a drug capable of antagonizing nondepolarizing neuromuscular blocking drugs, as well as several classes of injectable sedative and anesthetic agents, were studied in 6 intact, awake horses. Plasma samples were assayed for 4-AP over a frequent sampling schedule for 8 hours after IV administration. The plasma 4-AP vs time data best fit a 2-compartment pharmacokinetic model. Distribution half-life was 7.4 minutes, elimination half-life was 259 minutes, volume of the central compartment was 0.89 L/kg, volume of distribution (area) was 1.98 L/kg, volu...
Studies on equine prematurity 2: Post natal adrenocortical activity in relation to plasma adrenocorticotrophic hormone and catecholamine levels in term and premature foals. Adrenocortical and medullary function was investigated during the immediate post natal period in premature and full term foals. High plasma cortisol concentrations were characteristic of the term foals in the first 2 h after birth and these were accompanied by significant arteriovenous differences in plasma cortisol across the umbilical circulation at birth, indicating enhanced adrenal activity before delivery. No such arteriovenous differences were detected in the premature group and post natal changes in plasma cortisol were minimal. The apparent inability of the premature foal adrenal to se...
Studies on equine prematurity 6: Guidelines for assessment of foal maturity. This paper describes criteria used to assess maturity of the newborn foal and their clinical application to field cases of prematurity and dysmaturity. Premature and mature foals may be clearly distinguished by their behavioural and physical characteristics. Measurement of haematological parameters (mean cell volume, total white cell and differential counts), pancreatic beta cell activity (plasma glucose and insulin levels), adrenocortical-medullary function (plasma cortisol, adrenocorticotrophic hormone and catecholamines) and the renin-angiotensin system (plasma renin substrate concentration...
Relationship between paired plasma and serum viscosity and plasma proteins in the horse. The relationship between paired plasma and serum viscosity measurements and plasma proteins, including fibrinogen, were compared in 106 horses with both normal and abnormal serum protein levels. There is a highly significant positive correlation between serum viscosity and total serum proteins and total globulin levels. The difference between plasma and serum viscosity correlated well with clottable fibrinogen concentration. Albumin levels showed a negative correlation with plasma and serum viscosity, globulins and fibrinogen. Simultaneous estimation of serum and plasma viscosity improves the ...
Isolation, partial identification and quantitative determination of four guaiphenesin glucuronides in plasma and urine of the horse by high-performance liquid chromatography. The isolation, partial identification and quantitative determination of four guaiphenesin glucuronides in plasma and urine of the horse is described. The identity of the glucuronides was checked by UV and fluorescence spectrophotometry, by NMR spectrometry and by mass spectrometry after permethylation. The applicability of the procedure to pharmacokinetic studies is demonstrated.
Measurement of plasma antithrombin III activity in healthy horses. A fluorometric assay was used to determine plasma antithrombin III (AT III) activities in 15 healthy adult horses. Nearly all plasma samples had an initial value of greater than 100% thrombin inhibited, so a 1:1 dilution of the prepared samples was performed. Following dilution, the mean value of the animals was 59.17 +/- 7.4% thrombin inhibited. Mares had significantly greater AT III activity than did geldings (P less than 0.01). The results of this study indicate the horse has more AT III activity than did other domestic species in which AT III activity has been reported.
