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Topic:Biochemistry
The study of biochemistry in horses encompasses the chemical processes and substances that occur within equine organisms. This field investigates the molecular interactions and pathways that are fundamental to horse physiology, including metabolism, enzyme activity, and genetic expression. Key areas of interest include the examination of metabolic disorders, nutrient absorption, and the biochemical basis of muscle function and energy production. Researchers utilize biochemical analysis to understand health and disease mechanisms in horses, contributing to the development of diagnostic tools and therapeutic strategies. This page gathers peer-reviewed studies and scholarly articles that explore various biochemical processes and their implications for equine health and performance.
Erythrocyte glutathione-S-transferase activity in animal species. This study was conducted to determine and compare the activities of glutathione-S-transferase (GST) in red blood cells of cattle, horses, pigs, goats, dogs, rabbits, rats and mice. The highest GST activity was found in mouse red blood cells followed by that of rats, dogs, cattle, pigs, goats and horses with the lowest activity in rabbits. There were significant differences between the GST activities from these various species. The species differences in GST activities correlate with the reported variable responses of the different species to different toxicants since erythrocyte GST plays a si...
Consideration of the optimum pH for the analysis of serum p-phenylenediamine oxidase activity in thoroughbred horses. The optimum pH for the measurement of serum p-phenylenediamine oxidase (Ox) activity was given (pH 6.6), and the relationship between serum ceruloplasmin (Cp) concentration and its Ox activity was established in healthy adult horses. In adult horses, serum antigenic Cp concentrations were measured by the single radial immunodiffusion (SRID) method with the affinity-purified antibody to equine plasma Cp and compared with its Ox activity. Efficient co-relation between Cp concentration and Ox activity in the sera (r = 0.93) and its Ox/Cp ratio were given. These results might contribute to the cal...
A comparison of the lipolytic and anticoagulative properties of heparin and pentosan polysulphate in the thoroughbred horse. The aim of the study was to develop a model for the pre-exercise elevation of plasma free fatty acids in the horse, with a view to its future use in investigations of fat metabolism during exercise. A comparison of the lipase releasing and anticoagulative effects of heparin and a related substance pentosan polysulphate was investigated. Furthermore, the ability of heparin and pentosan polysulphate to affect an increase in plasma free fatty acid concentration, when co-administered with-a triglyceride emulsion, was quantified. Doses of 0.39 and 1.3 mg kg-1 body wt of heparin and pentosan polysul...
Pharmacokinetics of intravenous and oral prethcamide in horses. The respiratory stimulant prethcamide is a mixture of equal parts of crotethamide and cropropamide. A specific and sensitive gas chromatographic method for the determination of crotethamide and cropropamide in horse plasma and urine is described. Both components of prethcamide were extracted from plasma and urine into dichloromethane. The extracts were analyzed by capillary gas chromatography with thermionic detection in the nitrogen-specific detection mode. The lower limits of quantitation were 4.0 ng ml-1 of plasma and 10.0 ng ml-1 of urine. Calibration curves were linear from 2.0-100 ng ml-...
Skeletal muscle characteristics and metabolic response to exercise in young standardbreds. To determine whether performance capacity in a group of young trained Standardbreds is related to skeletal muscle characteristics and metabolic response to exercise. Methods: 13 clinically normal 2-year-old Standardbreds. Methods: Venous blood and middle gluteal muscle biopsy samples were obtained from each horse within 1 to 2 minutes after trotting at high speed for 1,600 m. Results: There was a positive correlation between plasma lactate and muscle glucose-6-phosphate (G-6-P) concentrations and trotting speed. There was a negative correlation between muscle adenosine triphosphate concentrati...
[Characterization of Rhodococcus equi isolates from horse and man]. In the present investigation 19 and 22 R. equi-cultures isolated from diseased horses and humans, respectively, could be correctly identified by their morphological, biochemical and serological properties. The rod-coccus life cycle appeared to be a common feature of almost all cultures investigated. The cultures were typeable with the typing system described by Prescott (1981). The predominant serotypes among the R. equi-isolates belonged to serotypes 1 and 2. Among the R. equi-isolates from horses haemagglutination-positive cultures were mainly found among isolates of serotype 1, those of ser...
Quantitative ionspray liquid chromatographic/tandem mass spectrometric determination of reserpine in equine plasma. A method based on ionspray liquid chromatography/tandem mass spectrometry (LC/MS/MS) was developed for the determination of reserpine in equine plasma. A comparison was made of the isolation of reserpine from plasma by liquid-liquid extraction and by solid-phase extraction. A structural analog, rescinnamine, was used as the internal standard. The reconstituted extracts were analyzed by ionspray LC/MS/MS in the selected reaction monitoring (SRM) mode. The calibration graph for reserpine extracted from equine plasma obtained using liquid-liquid extraction was linear from 10 to 5000 pg ml-1 and t...
Subjecting horse spermatozoa to hypoosmotic incubation: effects of ouabain. Although hypoosmotic tests are widely used to assess spermatozoal quality in different species, they have not been used extensively in the stallion. Moreover, the role of the Na (+)K (+), ouabain sensitive-ATP-ase in the response of equine sperm to hypoosmotic shock is not well understood. This study tests two hypotheses: 1) that equine spermatozoa will respond to a hypoosmotic medium by swelling of the tail, and 2) that addition of ouabain will increase the percentage of swollen sperm tails. Ejaculates from 3 stallions were collected with an artificial vagina and diluted in Kenney's medium (T...
The influence of progesterone-induced proteins on glucose metabolism in early equine embryos. The influence of different maternal plasma progesterone concentrations on embryonic glucose metabolism was studied. Uterine flushes were obtained after treating ovariectomized mares (n = 3) with 0 (control), 100 or 200 mg progesterone daily for 7 d. A group of progesterone-induced proteins (PIP) of Mr approximately 20,000 were identified in flushes from progesterone treatments by SDS-PAGE but were not observed in control flushes. Progesterone-induced proteins were removed from half the pooled flush in each treatment group by Sepharose blue CL-6B. In a 3 x 2 factorial (progesterone treatments, ...
Production of free estrogens and estrogen conjugates by the preimplantation equine embryo. In vitro production of free estrogens and estrogen conjugates by intact Day 12.5, 13.5 and 14.5 equine embryos was measured at 2-h intervals over a 24-h culture period. Production of free estrogens was higher for Day 14.5 than Day 12.5 embryos. Differences in production of conjugated estrogens were not significant, but a trend toward increased production with increased age of embryo was apparent. No trend toward increased free and conjugated estrogen production per cell was observed with age. Embryo diameter and number of cells increased with age but varied considerably within groups. The amou...
1H-NMR study of inter-segmental hydrogen bonds in sperm whale and horse apomyoglobins. NMR signals for HisB5 N(delta)H and HisEF5 N(epsilon)H protons of sperm whale and horse apomyoglobins were assigned and compared with the corresponding signals of the holoproteins in terms of pH and temperature dependence behaviors of their shifts and line widths in order to gain insight into structural difference between the apoproteins and the holoproteins. Since these protons are involved in internal hydrogen bonds at the interfaces between the B helix and the GH corner and between the EF corner and the H helix, local structures of the interfaces in these proteins have been inferred from th...
High-performance liquid chromatographic determination of N-alpha-acetyl-L-carnosine in equine plasma. N-alpha-Acetyl-L-carnosine (NAcCAR) in perchloric acid extracts of equine plasma was assayed by high-performance liquid chromatography on a 3 microns Hypersil ODS (150 x 4.6 mm I.D.) column eluted with 5 mM phosphoric acid-1 mM triethylamine, pH 2.58. NAcCAR was isolated by solid-phase extraction on Isolute PRS (propylsulphonyl) columns. The HPLC mean retention time for NAcCAR was 5.9 +/- 0.2 min. The recovery from plasma by solid-phase extraction was 93.9-99.7% and lower limit of detection in plasma was 0.18 microM. The normal NAcCAR concentration in equine plasma was 2.4 +/- 0.3 microM. The ...
High-performance liquid chromatographic determination of imidazole dipeptides, histidine, 1-methylhistidine and 3-methylhistidine in equine and camel muscle and individual muscle fibres. The combined solid-phase extraction (Isolute PRS columns) and reversed-phase gradient HPLC method presented provides a sensitive, reproducible and selective quantification of carnosine, balenine, homocarnosine, histidine, 1-methylhistidine and 3-methylhistidine in equine and camel muscle and individual muscle fibres. Recoveries were 91-115%. Lower limits of detection were 0.005-0.010 mmol kg-1 dry muscle. The compounds were isolated from other physiological amino acids and small peptides and resolved within a single chromatographic run of 55 min. Concentrations of these compounds in equine myo...
Dose-response of X-irradiated human and equine lymphocytes. We have investigated and compared DNA damage and cell killing induced in human and equine lymphocytes after in vitro X-irradiation. Our data show that the cytogenetic and the lethality effects are both greater in equine lymphocytes, but that the difference is wider for lethality. The ratios between doses inducing the same effect are 1.3, 1.7 and 9.4 for the number of binucleated cells with micronuclei, micronucleus frequency in binucleated cells and DNA synthesis inhibition, respectively. The very different radiosensitivity observed for the two mammalian species encourages us to use their lymp...
Total cholinesterase activity in discrete brain regions and retina of normal horses. The research evaluates cholinesterase activity across different brain regions in horses to better understand its role in neuromuscular function and how it can be affected by certain toxic exposures. Cholinesterase [...]
Effects of delayed serum separation and long-term storage on the measurement of thyroid hormones in equine blood samples. Studies were conducted to determine the effects of delaying the separation of serum from the clot and of long-term storage of serum samples on the measurement of thyroid hormones in blood from horses using a fluorescence polarization immunoassay. The measured concentrations of T3 and T4 were not affected by leaving serum on the clot for as long as 24 hours at room temperatures. Storage of serum for 19 to 22 months at -20 degrees C resulted in significant increases of measured T4, but not T3. These studies support previous work demonstrating that thyroid hormones are resistant to degradation, i...
Method for the growth of equine airway epithelial cells in culture. A serum-free cell culture method was developed for equine tracheal epithelial cells which allowed the growth and characterisation of the phenotypical properties of this cell type. Several variables influenced the efficacy of the attachment and growth of the isolated cells. Serum and a collagen matrix were essential components for efficient cell attachment. Once attachment had occurred, cell growth was enhanced by a serum-free medium containing bovine pituitary extract, retinoic acid, insulin, hydrocortisone, transferrin, epidermal growth factor, adrenaline and triiodothyronine. The mean time t...
Effect of allopurinol on the formation of reactive oxygen species during intense exercise in the horse. Allopurinol was administered to six horses in a cross-over study to determine the relative contribution of xanthine oxidase (XO) activity to the formation of reactive oxygen species (ROS) in the horse during intense exercise. Exercise increased the mean (SEM) plasma lipid hydroperioxide concentration to a maximum of 492.7 (33.4) microM within one minute of exercise completion and maximum levels of both oxidised glutathione (GSSG) in haemolysates of red blood cells and the glutathione redox ratio (GRR) occurred 20 minutes after exercise (87.2 [12.2] microM and 8.9 [0.9] per cent, respectively)....
Gelatinolytic activity in tracheal aspirates of horses with chronic obstructive pulmonary disease. The gelatinolytic activity in tracheal aspirates (TA) of horses with chronic obstructive pulmonary disease (COPD) was analyzed using SDS-PAGE-gelatin-gel electrophoresis (zymography) and compared to TAs from healthy controls. The 110-90 kD MMP-9 type gelatinase was high in symptomatic disease phases (permanent disease 0.46 +/- 0.15, p < 0.001; or intermittent disease 0.47 +/- 0.12, p < 0.001) compared to healthy controls (0.10 +/- 0.07). Similarly, the overall gelatinolytic activity, the activity in high-mw gelatinolytic bands (210-190 and 150 kD) and in proteolytically processed fragmen...
Biochemical and site-specific effects of insulin-like growth factor I on intrinsic tenocyte activity in equine flexor tendons. To examine the site-specific and dose-dependent effects of insulin-like growth factor I (IGF-I) on normal equine tendon in vitro. Methods: Superficial digital flexor tendon explants derived from a euthanatized 3-year-old horse. Methods: Explants in culture were treated with 0, 100, 250, or 500 ng of IGF-I/ml for 14 days with an end-stage radiolabel of 20 microCi of [3H]proline/ml or 5 microCi of [3H]thymidine/ml. The tendon tissues were then analyzed biochemically for hydroxyproline content by reverse-phase high-performance liquid chromatography, DNA content by fluorometry, and glycosaminoglyc...
Some parameters influencing immunoassay of human and horse myoglobins. It was noted that human and horse sera as well as human heart and skeletal muscle homogenates or extracts distinctly decrease immunoassays of purified myoglobins. The assays of homogenate and extract myoglobins could be many times increased by precipitation certain proteins with concentrated ammonium sulfate or sodium chloride. Also in homogenates and extracts incubated for several days increased assays of myoglobins were noted. The obtained results indicate that both myoglobins occur in complex with other tissue component(s).
Altered biological activity of equine chondrocytes cultured in a three-dimensional fibrin matrix and supplemented with transforming growth factor beta-1. To determine the effects of transforming growth factor-beta 1 (TGF-beta 1) on the synthesis of DNA, collagen, and proteoglycans (PG) by equine chondrocytes. Methods: Articular cartilage obtained from multiple joints of a 4-month-old foal. Methods: Chondrocytes were isolated by collagenase digestion, cultured in monolayer, trypsinized, and implanted at a cellular density of 10 x 10(6) chondrocytes/ml in a three-dimensional fibrin matrix. Chondrocytes in culture were supplemented with TGF-beta 1 at concentrations of 0, 1, 5, or 10 ng/ml in serum-free medium or medium containing fetal bovine seru...
Effect of two virus inactivation methods: electron beam irradiation and binary ethylenimine treatment on determination of reproductive hormones in equine plasma. Ionizing irradiation and binary ethylenimine treatment have previously been shown to be effective for in-vitro inactivation of virus in biological material. In the present study the 2 methods were tested for possible effects on measurable concentrations of reproductive hormones in equine plasma (luteinizing hormone (LH), folliclestimulating hormone (FSH), progesterone (P4), and oestradiol-17 beta (E2)). The inactivation methods were electron beam irradiation with a dose from 11 to 44 kGy or treatment with binary ethylenimine (BEI) in concentrations of 1 and 5 mmol/L. Generally, there was a clo...
Biochemical, histochemical, and immunohistochemical characterization of distal tibial osteochondrosis in horses. To compare the biochemical, histochemical, and immunohistochemical profiles of articular cartilage from horses with naturally acquired distal tibial osteochondrosis (OC) with cartilage from a similar location in clinically normal horses. Methods: 9 affected horses (group 1, 16 OC lesions) and 4 control horses (group 2, 8 normal osteochondral specimens). Methods: OC specimens were collected during arthroscopic removal of the fragment, and control specimens were collected by aseptic osteotomy. Uronic acid, total protein, total glycosaminoglycan (GAG), chondroitin sulfate (CS), and keratan sulfat...
Proteoglycan metabolism of equine articular chondrocytes cultured in alginate beads. Equine chondrocytes were cultured in vitro for 30 days in ionically gelled alginate beads. The alginate polymerises into a stable gel in the presence of divalent cations (calcium), and rapid depolymerisation in the presence of a calcium chelator releases the viable chondrocytes. The chondrocytes maintained a spherical appearance for 30 days in culture, in marked contrast to monolayer cultures, which develop a dedifferentiated fibroblastic morphology. The major proteoglycan molecule produced by the encapsulated chondrocytes was aggrecan, of similar hydrodynamic size to aggrecan molecules presen...
Myoglobin oxygen dissociation by multiwavelength spectroscopy. Multiwavelength optical spectroscopy was used to determine the oxygen-binding characteristics for equine myoglobin. Oxygen-binding relationships as a function of oxygen tension were determined for temperatures of 10, 25, 35, 37, and 40 degrees C, at pH 7.0. In addition, dissociation curves were determined at 37 degrees C for pH 6.5, 7.0, and 7.5. Equilibration was achieved with a myoglobin solution, at the desired temperature and pH, and 16 oxygen-nitrogen gas mixtures of known oxygen fraction. Correction for the inevitable presence of metmyoglobin was made by using a three-component least squ...
Plasma von Willebrand factor in thoroughbreds in response to high-intensity treadmill exercise. To determine whether plasma von Willebrand factor (vWf) concentration changes in horses during and after treadmill exercise. Methods: 5 mature, fit Thoroughbreds. Methods: A blood sampling catheter was placed in the right jugular vein. A warm-up period was followed by a 3-minute rest period. Horses were galloped at racing pace until fatigued (about 2 minutes). Blood samples were collected prior to warm-up, during the postwarm-up rest period, 1 minute into the run, at cessation of the run, and 5 to 120 minutes after cessation of the run. vWf activity was measured by ELISA and corrected for plas...
Adaptation of equine herpesvirus 1 to unnatural host led to mutation of the gC resulting in increased susceptibility of the virus to heparin. Heparin extensively inhibited infection of MDBK cells by equine herpesvirus 1 (EHV-1) strains adapted to bovine cells or hamsters, while the reagent merely reduced infectivity of strains passaged only in equine cells. The gC of two strains adapted to non-equine cells seemed to have higher affinity for heparin, although the reagent bound to both the gC and gB of all strains tested. Amino acid substitutions of the gC of the EHV-1 strains adapted to non-equine cells converged on the hydrophilic regions, amino acid residues 92 to 175, resulting in the glycoprotein becoming more cationic. These res...
Local electrostatic potentials in pyridoxal phosphate labelled horse heart cytochrome c. The present work shows the application of an optical label pyridoxal phosphate (PLP) for the experimental determination of local electrostatic potentials in singly substituted cytochromes c modified by pyridoxal phosphate at Lys 79 (PLP-Lys-79-cyt.c) or at Lys 86 (PLP-Lys-86-cyt.c). PLP has also been used to calculate the pKa values of all ionizable groups and the electrostatic potentials in the modified proteins and to analyse their properties. The experimental pKa values for the pyridine nitrogen and phenolic hydroxyl of the bound label were obtained from pH-dependent absorbance and fluoresc...
[Animal systemic iron sources utilized in vitro by staphylococci]. Under iron-restricted conditions staphylococcal strains could utilize in vitro several animals body iron sources in form of bovine haemoglobin, hemin, lactoferrin and transferrin, ovotransferrin, horse myoglobin ferritin and cytochrome C. Spectrum of utilized iron sources was not dependent on species affiliation and kind of siderophores system. Strains isolated from clinical materials utilized largest spectrum of animal iron body sources.
