Topic:Serum
Serum in horses refers to the component of blood that remains after the removal of cells and clotting factors. It contains a variety of proteins, electrolytes, hormones, and metabolic waste products. Serum analysis is a valuable tool in veterinary medicine for assessing the health status of horses. It provides insights into organ function, nutritional status, and the presence of disease. Common parameters measured in equine serum include enzymes, such as aspartate aminotransferase (AST) and gamma-glutamyl transferase (GGT), as well as electrolytes like sodium and potassium. This page assembles peer-reviewed research studies and scholarly articles that explore the composition, diagnostic applications, and implications of serum analysis in equine veterinary practice.
Gentamicin pharmacokinetics in horses given small doses of Escherichia coli endotoxin. The pharmacokinetics of gentamicin (3 mg/kg of body weight) were evaluated in 6 healthy horses and in 6 horses after they were given Escherichia coli endotoxin (0.113 microgram/kg). In the horses given endotoxin, there were a maximum temperature increase of 1.97 +/- 0.44 degrees (C) and a fever index (between the 2 groups) of 8.754 units. Other mild signs of endotoxemia also occurred. Statistically significant changes were not observed in the rate constants for distribution (alpha) or elimination (beta) or in body clearance (ClB) of gentamicin in the 2 groups of horses. In the horses given end...
Species dependent gentamicin pharmacokinetics and nephrotoxicity in the young horse. Gentamicin pharmacokinetics and nephrotoxic potential were evaluated in twelve 2 to 3 month-old horses. Whereas recent evidence in our clinic indicated that young horses may be especially susceptible to gentamicin nephrotoxicity, young rabbits and rats are usually resistant. Gentamicin (4.5 mg/kg) was given by rapid intravenous injection. Serum gentamicin concentrations over a 13-hour period were fitted to an open, two-compartment, pharmacokinetic model. Subsequently, the same horses were divided into groups of 3 horses each. Each group received 0, 2.2, 4.4 or 8.8 mg gentamicin/kg, intramuscul...
A pharmacokinetic study of digoxin in the horse. Digoxin was administered orally and intravenously to seven healthy adult mares and geldings in two separate trials. At a dose of 44 microgram digoxin/kg body weight, the oral study was characterized by an absorption phase with a mean (+/- 1 standard deviation) peak serum digoxin concentration of 2.21 ng/ml (+/- 0.45) at a mean of 2.29 h (+/- 1.52) after administration. A second rise in serum digoxin concentration started about 6-8 h after administration and extended to about 20 h after administration. The mean bioavailability (F) was 23.38% (+/- 5.96). At a dose of 22 microgram digoxin/kg body...
Serum albumin values from healthy cattle, sheep and horses determined by the immediate bromocresol green reaction and by agarose gel electrophoresis. Serum albumin concentrations were measured by the immediate reacting bromocresol green (BCG) method and by agarose gel electrophoresis in healthy cattle, sheep and horses. No statistically significant differences were found between the values obtained by the two methods. The immediate reacting BCG method is quicker and cheaper when used under the conditions described.
Further purification and characterisation of horse IgE. Horse IgE was isolated from a serum pool collected from foals naturally infected with endoparasites. The serum was precipitated with ammonium sulfate, delipidated with dextran sulfate and further purified by gel filtration, anionic exchange, immunosorption or preparative polyacrylamide gelelectrophoresis. By these methods IgE could be isolated at a purity of 81%. The sera from rabbits immunized with the purified horse serum fractions were tested using reversed passive cutaneous anaphylaxis and an enzyme linked immunosorbent assay (ELISA). By the ELISA method cross reaction of rabbit anti horse...
Influenza hemagglutination inhibiting activity in respiratory mucus from horses with chronic obstructive pulmonary disorders (heaves syndrome). Samples of mucus from the lower trachea were collected from 53 horses with chronic obstructive pulmonary disease and from 24 clinically normal horses. Serum samples were collected from 35 of the horses with chronic obstructive pulmonary disease and from the 24 normal horses. Samples were tested for inhibition of hemagglutination by influenza A equine 1 and 2 viruses. There were high levels of hemagglutination inhibiting activity against influenza A equine 1 in mucus samples from horses with chronic obstructive pulmonary disease.
Analysis of serum and lymphocyte surface IgM of healthy and immunodeficient horses with monoclonal antibodies. Nine monoclonal antibodies which reacted with equine immunoglobulin (Ig)M and not other equine Ig and serum proteins were prepared. Cells producing antibodies (C 1.9) which precipitated with IgM and bound to staphylococcal protein A were triple-cloned (C 1.9/3.2) and the antibodies further characterized. Monoclonal antibody C 1.9/3.2 reacted with an IgM determinant present on serum IgM from horses of several breeds. Studies with 125I-labeled IgM revealed the presence of this determinant on all IgM molecules. The monoclonal antibody enabled quantitation of IgM in presuckling foal and adult hors...
Sweet itch: responses of clinically normal and affected horses to intradermal challenge with extracts of biting insects. In a study of the skin reactivity of horses with lesions of sweet itch, six clinically normal horses and seven affected horses were challenged intradermally with extracts of Culicoides, Stomoxys, Tabanidae and Culex species. All the affected horses and three of the normal horses responded strongly to the culicoides extract. The skin reactions in the affected horses reached their maxima within 4 h in the majority of animals. Skin reactivity to culicoides was transferred to normal horses with serum from affected animals confirming that the reaction was an immediate hypersensitivity reaction. Thr...
Copper and zinc levels in the blood of thoroughbreds in training in the United Kingdom. The concentration of copper and zinc in the blood and sera of over 300 Thoroughbreds in training was determined by atomic absorption between February 1979 and July 1981. The mean (+/- sd) concentration of copper in the serum of stabled Thoroughbreds (79 +/- 16 micrograms/dl) was significantly (P less than 0.0001) lower than that of those at grass (101 +/- 26 micrograms/dl), whereas the mean serum zinc concentration of stabled Thoroughbreds (170 +/- 54 micrograms/dl) was higher than that of those at grass (111 +/- 45 micrograms/dl). No such differences were observed in whole blood. There were m...
Fatty acid composition of serum lipids in fasting ponies. Alterations in the fatty acid distribution of total lipid extracts and 4 of the major lipid subclasses of serum in ponies fasted overnight and for 4 and 7 days were determined. Although increases in 16:0, 16:1, and 18:3 omega 3 were observed, decreased amounts of 18:0 and 18:2 omega 6 combined to cause no significant change in the saturated to unsaturated fatty acid ratio in the total extracts. Phospholipid became somewhat preferentially enriched in saturated fatty acids due to a decrease in 18:1, although this response was variable. The free fatty acid and triglyceride fractions both showed i...
Pharmacokinetics of phenytoin (diphenylhydantoin) in horses. The pharmacokinetics of the anti-convulsant phenytoin were investigated in clinically healthy horses after oral (p.o.) and intravenous (i.v.) administration. A single dose of phenytoin (8.8 mg/kg body weight) was given i.v. as a bolus to nine horses and one horse received 13.2 mg/kg. A two-compartment open model was used to describe the disposition of phenytoin. Four of the horses that received an i.v. dose (three at 8.8 mg/kg and one at 13.2 mg/kg) were then given the same dose 3 days later by the oral route. Phenytoin achieved a peak concentration in serum within 1-4 h after p.o. administrat...
Pharmacokinetics and protein binding of morphine in horses. Morphine could be detected in horses dosed with 0.1 mg of drug/kg of body weight for up to 48 hours in blood and 144 hours in urine. This dose of morphine elicited no observable effects and is a suggested analgesic dose. Computer analysis revealed that a 3-compartment open system was the best fitting model with a serum half life (t1/2(beta)) of 87.9 minutes and a urine t1/2(beta) of 101.1 minutes. Binding to equine serum proteins was linear over a drug concentration range of 3.88 X 10(-5)M to 3.50 X 10(-8)M and averaged 31.6%. In RBC-partitioning experiments, 78.1% of the drug was found in the...
Adaptation of human diploid fibroblasts in vitro to serum from different sources. The growth of two human diploid skin fibroblast cell lines, originally grown in medium supplemented with foetal bovine serum and later adapted to medium supplemented with newborn bovine, bovine calf or horse serum, has been studied. Prolonged generation times increased cell volumes and decreased plating efficiencies were observed in cultures grown in newborn bovine, bovine calf or horse serum. In general, the deleterious effects were most severe as a result of growth in bovine calf or horse serum. In the light of the present findings, we believe investigators should exert great caution in swit...
Biochemical and haematological effects of phenylbutazone in horses. Five matched pairs of horses were used to investigate the effects of phenylbutazone on a range of physiological, biochemical and haematological variables. The drug was given by mouth daily for 15 consecutive days at the manufacturer's recommended dose rates to one group of horses (Group A); the second group (Group B) received equivalent doses of a placebo. For some of the measured parameters, significant changes were recorded in both groups, indicating background instability. Significant decreases in serum total protein, albumin, plasma pH, viscosity and magnesium, and an increase in albumin: ...
Hypoglycemic seizures in a Shetland pony. A 12-year-old, 195 kg Shetland pony broodmare had eight seizures between May 29 and August 7, 1979. Plasma glucose levels during three of these seizures were markedly depressed (16, 18 and 19 mg/100 ml). Serum insulin levels were elevated during two of the seizures (86.0 and 97.7 microU/ml). Although a fasting hypoglycemia was not demonstrated, plasma glucose values during a normal day were abnormal; a plasma glucose level of 42 mg/100 ml was noted eight hours post-feeding. Serum insulin values obtained during an oral glucose tolerance test and intravenous glucagon tolerance test were consiste...
Trimethoprim-sulfadiazine in the horse: serum, synovial, peritoneal, and urine concentrations after single-dose intravenous administration. Six healthy adult mares were given a single IV injection of trimethoprim (TMP)-sulfadiazine (SDZ) at a dosage rate of 2.5 mg of TMP/kg of body weight and 12.5 mg of SDZ/kg. Serum, synovial, peritoneal, and urine TMP-SDZ concentrations were measured serially over a 48-hour period. The highest measured mean concentrations of TMP and SDZ were found in the first (0.5 hour) sample of serum, synovial fluid, and peritoneal fluid. The mean peak concentrations of TMP and SDZ averaged 4.37 micrograms/ml and 21.81 micrograms/ml for serum, 2.95 micrograms/ml and 15.31 micrograms/ml for synovial fluid, and...
Examination of the origin of increased equine serum alkaline phosphatase concentrations. Serum alkaline phosphatase activity was found to be increased in 32.6% of equine samples analyzed at the Ontario Veterinary College over an 18 month period. An attempt was made using sensitivity to L-phenylalanine and heat to identify the origin of increased serum alkaline phosphatase isoenzymes present in 44 clinical cases. No difference in sensitivity to either procedure was observed for serum alkaline phosphatase from groups of foals and horses representing different clinical problems. Alkaline phosphatase of osseous tissue origin appeared to be the major source of activity for each group o...
Serum and red cell folate and serum vitamin B12 levels in horses. Vitamin B12 and folate concentrations were determined by radioimmunoassay in groups of horses in Queensland. Highest serum vitamin B12 levels were found in supplemented performance horses. These, together with pastured horses that included pregnant and lactating mares, had significantly greater serum folate activity than permanently stabled animals. The range of red cell folate concentrations was much narrower in horses in training than from any other group. Red cell folate may be a better indicator of a horse's folate status than the serum folate value. Vitamin B12 and folate concentrations w...
Gamma Glutamyl Transferase in domestic animals. In domestic animals, Gamma Glutamyl Transferase is mainly in the kidneys, the pancreas and the intestine; its liver activity is relatively high in cows, horses, sheep and goats and very low in dogs, cats and birds. The use of plasma reference values can help to interpret the variations of serum GGT mainly in hepatobiliary diseases of cattle, sheep, goats and cholestatic disorders of dogs. Urinary GGT is a good test of kidney toxic damage.
Pharmacokinetics of erythromycin in foals and in adult horses. The pharmacokinetic parameters of erythromycin in foals were determined following intravenous administration of 5.0 mg/kg to animals aged 1, 3, 5 and 7 weeks. The distribution of the drug was described by a two-compartment open model, and no significant differences were observed between coefficients on which the parameters were based. Pharmacokinetic values were also determined for four mares given 5.0 mg/kg intravenously and for six 10-12-week-old foals given 20.0 mg/kg intravenously. The half-life of erythromycin for all groups of animals (foals less than 7 weeks, mares, foals 10-12 weeks) w...
Ticarcillin administration to the equine: Intrauterine and intramuscular. Serum levels of ticarcillin disodium, a semi-synthetic penicillin (Beecham Laboratories, Bristol, Tennessee, 37620), were measured at various time intervals up to and including 24 h after intrauterine and intramuscular administration in adult female horses. Three separate studies were conducted in Part I: in the first and second studies, serum levels were measured after intrauterine administration of 1 and 3 g of ticarcillin, respectively, and in the third study, levels were measured after intramuscular administration of 6 g of ticarcillin. In Part II, serum levels of ticarcillin were measured...
Equine complement activation as a mechanism for equine neutrophil migration in Onchocerca cervicalis infections. Extracts of Onchocerca cervicalis, an equine parasite, were incubated with radiolabeled equine neutrophils and neutrophil migration was assessed for factors derived from the parasite itself or for host-derived factors after incubation of these same parasite extracts with equine serum. No stimulus for cell migration was observed in saline extracts of adult worms, uterine microfilariae, or skin microfilariae at any dosage tested. However, after incubation of saline extracts with fresh normal equine sera a marked stimulus for neutrophil migration was observed. Ablation of this biologic activity w...
Diagnostic value of intestinal alkaline phosphatase in horse serum. Antiserum directed against equine intestinal Alkaline Phosphatase (ALP) was produced in rabbits and used to develop a sensitive and quantitative assay for the detection of intestinal ALP in equine serum. This assay was then used to measure the half-life of intravenously injected intestinal ALP and to determine if the intestinal ALP was present in normal horse sera, sera from horses presented for lesions not involving the gastrointestinal tract and sera from horses presented with lesions involving the gastrointestinal tract. The results suggest that intestinal ALP is not likely to appear in equ...
A reagin-like antibody in horse serum: 1. Occurrence and some biological properties. The demonstration of a reagin-like antibody against Culicoides pulicaris extract in the serum of horses and ponies affected with recurrent seasonal dermatitis (sweet itch) is reported. This antibody can confer Prauznitz-Küstner (P-K) sensitivity on homologous skin for up to 5 days and, like human IgE, is thermolabile and susceptible to 2-mercaptoethanol reduction. It is eluted on diethylaminoethyl dextran-52 anion exchange chromatography independently of IgG, IgG(T) and IgM, and its elution characteristics indicate similarity in net molecular charge to human IgE. The P-K response observed in ...
Kinetic and structural relationships of transition monomeric and oligomeric carboxyl- and choline-esterases. The kinetic and structural relationships of eight electrophoretically pure mammalian serum and liver serine carboxylesterases (CE) and cholinesterases (ChE) have been studied. Eight CE's and ChE's, which were fully resolved but only partially purified, provided additional information. Five of the electrophoretically pure esterases were monomeric, and of these, four belonged to a new and widely distributed class. These four monomeric esterases hydrolyzed choline esters, but at widely differing rates. Thus two were termed monomeric butyrylcholinesterases, mBuChE I and II, and two were monomeric ...
Serum concentrations of penicillin in the horse after administration of a variety of penicillin preparations. Twelve geldings were used to evaluate serum levels of penicillin following the intravenous (iv) and intramuscular (im) injection of benzylpenicillin, im procaine penicillin and im fortified benzathine penicillin, at a variety of dose rates. Blood samples were collected up to 7 h after iv and im benzylpenicillin, up to benzathine penicillin. Results were analysed using an analysis of variance and regression analyses were used to calculate the time taken for the serum penicillin concentration to decline to 0.5 micrograms/ml. As a result of the experiments the following dosage regimes could be re...
Duration of maternally derived immunity to tetanus and response in newborn foals given tetanus antitoxin. Serum tetanus antitoxin (TAT) concentrations were measured in a group of 30 foals from birth to 4 months of age. Five of 30 foals (16.6%) had serum titers less than 0.01 IU of TAT/ml by 1 month of age. At 2 months of age, 17 of 28 foals (60.7%) had titers less than 0.01 IU/ml. By 3 months of age, 22 of 29 (75.5%) foals tested had titers of less than 0.01 IU/ml. At the age of 4 months, 24 of 29 foals (82.1%) had titers of less than 0.01 IU/ml. The TAT given to foals at birth resulted in an immediate increase in titer when circulating antitoxin was absent or minimal. Titers considered protective...