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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.
Influence of calcium salts and bovine thrombin on growth factor release from equine platelet-rich gel supernatants. To compare five activation methods in equine platelet-rich plasma (PRP) by determination of platelet-derived growth factor BB (PDGF-BB) and transforming growth factor beta 1 (TGF-β1) concentrations in platelet-rich gel (PRG) supernatants. Methods: Platelet-rich plasma from 20 horses was activated by calcium chloride (CC), calcium gluconate (CG), bovine thrombin (BT), and their combinations, BTCC and BTCG. Both growth factor concentrations in PRG supernatants were measured by ELISA and compared with plasma and platelet lysates (PL) over time. Results: Growth factor concentrations were signific...
β-endorphin immunoreactivity during anaesthesia in equidae. To determine the effects of surgery, hypoxia, hypercapnia and flunixin administration on plasma β-endorphin immunoreactivity (BEI) in anaesthetized horses. Methods: Prospective crossover study. Methods: Six healthy adult Welsh Mountain ponies and seven healthy adult Thoroughbreds. Methods: Ponies were anaesthetized with thiopentone and halothane or with pentobarbitone and the horses with guaiphenesin, thiopentone and halothane. Ponies were anaesthetized for 2 hours and on separate occasions underwent a period of hypoxia, hypercapnia, anaesthesia only, or were given flunixin at induction. The ...
Effects of guaiphenesin on the equine electroencephalogram during anaesthesia with halothane in oxygen. To identify and characterize the effects of guaiphenesin (GGE) on the electroencephalogram during halothane anaesthesia. Methods: Prospective controlled study. Methods: Eight healthy Welsh mountain pony geldings between 5 and 9 years old and weighing between 270 and 330 kg (mean 301 kg). Methods: Anaesthesia was induced with thiopentone and maintained using halothane in oxygen. End tidal halothane was maintained above 0.75 and below 0.85%. The EEG was recorded continuously and a binaural broad band click stimulus was provided throughout the experiment at 6.1224 Hz. An infusion of 1500 mg GGE w...
Mitochondrial ATP is required for the maintenance of membrane integrity in stallion spermatozoa, whereas motility requires both glycolysis and oxidative phosphorylation. To investigate the hypothesis that oxidative phosphorylation is a major source of ATP to fuel stallion sperm motility, oxidative phosphorylation was suppressed using the mitochondrial uncouplers CCCP and 2,4,-dinitrophenol (DNP) and by inhibiting mitochondrial respiration at complex IV using sodium cyanide or at the level of ATP synthase using oligomycin-A. As mitochondrial dysfunction may also lead to oxidative stress, production of reactive oxygen species was monitored simultaneously. All inhibitors reduced ATP content, but oligomycin-A did so most profoundly. Oligomycin-A and CCCP also sign...
The Lin28 Expression in Stallion Testes. The molecular markers for specific germ cell stages can be utilized for identifying, monitoring, and separating a particular stage of germ cells. The RNA-binding protein Lin28 is expressed in gonocytes of human fetal testes. The Lin28 expression is restricted to a very small population of spermatogonial cells in human, mice, and monkey. The main objective of this study was to investigate the expression pattern of Lin28 in stallion testes at different reproductive stages. Based on the presence or absence of full spermatogenesis and lumina in seminiferous tubules, the testicular samples were cat...
Development and application of a UHPLC-MS/MS method for the simultaneous determination of 17 steroidal hormones in equine serum. A new, fast and simple analytical method that is able to identify and quantify simultaneously 17 steroid hormones and metabolites (pregnenolone, 17-OH-pregnenolone, progesterone, 17-OH-progesterone, androsterone, androstenedione, dehydroepiandrosterone, dehydroepiandrosterone sulfate, testosterone, cortisol, corticosterone, aldosterone, 11-deoxycortisol, 11-deoxycorticosterone, dihydrotestosterone, estrone and estradiol) has been developed in equine serum using the ultra-high-performance liquid chromatography-tandem mass spectrometry technique. A total of 400 µl of sample was deproteinized ...
Glucocorticoid metabolism in equine follicles and oocytes. The objective of this study was to determine whether (1) systemic and intrafollicular cortisol concentrations in horses are directly related and (2) supraphysiological levels of glucocorticoids affect in vitro maturation (IVM) rates of oocytes. Specifically, we studied the (1) changes in the intrafollicular cortisol and progesterone in context with granulosa cell gene expression during maturation of equine follicles (from 5-9 mm, 10-14 mm, 15-19 mm, 20-24 mm, and ≥25 mm in diameter) and (2) effects of cortisol supplementation on IVM rates and gene expression of equine cumulus-oocyte comple...
Nitrite coordination in myoglobin. The coordination of nitrite in myoglobin (Mb) has been characterized by resonance Raman spectroscopy and the frequencies of the nitrite bound to the heme Fe as well to the 2-vinyl have been computed by density functional theory (DFT) calculations. The DFT Natural Bond Orbital (NBO) analysis and the extensive isotope-labeling in the resonance Raman experiments indicate that NO (O1NO2) is bound to the heme Fe via O1. Based on the vibrational characterization of the reversible transition between low and high spin FeONO/2-nitrovinyl species, we suggest that the key step that triggers the spin-chan...
Microvesicle-mediated Wnt/β-Catenin Signaling Promotes Interspecies Mammary Stem/Progenitor Cell Growth. Signaling mechanisms that regulate mammary stem/progenitor cell (MaSC) self-renewal are essential for developmental changes that occur in the mammary gland during pregnancy, lactation, and involution. We observed that equine MaSCs (eMaSCs) maintain their growth potential in culture for an indefinite period, whereas canine MaSCs (cMaSCs) lose their growth potential in long term cultures. We then used this system to investigate the role of microvesicles (MVs) in promoting self-renewal properties. We found that Wnt3a and Wnt1 were expressed at higher levels in MVs isolated from eMaSCs compared wi...
Identification of the most abundant proteins in equine amniotic fluid by a proteomic approach. Characterisation of the physiologic equine amniotic fluid (AF) proteome is a prerequisite to study its changes during diseases and discover new biomarkers. The aim of this study was to identify by a proteomic approach the most abundant proteins of equine AF. AF samples were collected at parturition from 24 healthy mares that delivered healthy foals. All samples were subjected to sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE) on 4-12% gels. A pool of the 24 samples, after SDS-PAGE, was cut in 25 slices, trypsin-digested and analysed by mass spectrometry (MS) for protein i...
Oxidative stress and DNA damage in horses naturally infected with Theileria equi. The aim of this study was to determine the concentrations of oxidative stress parameters and DNA damage in horses infected by Theileria equi. Initial screening of 110 horses with duplex PCR enabled the selection of 30 infected horses with T. equi and 30 free of infection (control). Specimens from the 60 horses were further analysed by determining the following oxidative stress parameters: extent of haemolysis (EH), plasma free haemoglobin (PHb), catalase (CAT), Cu,Zn superoxide dismutase (SOD1), paraoxonase (PON1), nitrite (NO), total nitrate and nitrite (NOx), malondialdehyde (MDA) and free t...
Isolated effects of external bath osmolality, solute concentration, and electrical charge on solute transport across articular cartilage. The metabolic function of cartilage primarily depends on transport of solutes through diffusion mechanism. In the current study, we use contrast enhanced micro-computed tomography to determine equilibrium concentration of solutes through different cartilage zones and solute flux in the cartilage, using osteochondral plugs from equine femoral condyles. Diffusion experiments were performed with two solutes of different charge and approximately equal molecular weight, namely iodixanol (neutral) and ioxaglate (charge=-1) in order to isolate the effects of solute's charge on diffusion. Furthermore,...
Doping control analysis of anabolic steroids in equine urine by gas chromatography-tandem mass spectrometry. Anabolic steroids are banned substances in equine sports. Gas chromatography-mass spectrometry (GC-MS) has been the traditional technique for doping control analysis of anabolic steroids in biological samples. Although liquid chromatography-mass spectrometry (LC/MS) has become an important technique in doping control, the detection of saturated hydroxysteroids by LC-MS remains a problem due to their low ionization efficiency under electrospray. The recent development in fast-scanning gas-chromatography-triple-quadrupole mass spectrometry (GC-MS/MS) has provided a better alternative with a sign...
Variability of lysozyme and lactoferrin bioactive protein concentrations in equine milk in relation to LYZ and LTF gene polymorphisms and expression. Equine milk is considered to be an interesting product for human nutrition, mainly owing to its low allergenicity and significant amounts of bioactive proteins, including lysozyme (LYZ) and lactoferrin (LTF). The present study assessed the effect of genetic factors on LYZ and LTF concentration variability in mare's milk. Results: Significant effects of horse breed and lactation stage on milk LYZ and LTF contents were observed. The highest level of LTF and the lowest concentration of LYZ were recorded for the Polish Warmblood Horse breed. The highest amounts of both proteins were found for the ...
Photoacoustic calorimetry studies of CO photo-dissociation from chloramine-T modified horse heart cytochrome-c. Treatment of horse heart Cytochrome-c (Cc) with N-chloro-4-toluosulfonamide (Chloramine-t, CT) results in the oxidation of methionine (Met) residues to the corresponding sulfoxide including the distal heme ligand, Met80. The resulting Fe-sulfoxide coordination is sufficiently labile in the ferrous form to be displaced by gaseous ligands, including CO. Photolysis of the CO-CT-Cc complex provides an opportunity to examine ligand binding dynamics that are associated with a relatively rigid distal heme pocket. In this work, photoacoustic calorimetry (PAC) was utilized to obtain the kinetics as wel...
Pharmacokinetics of dextromethorphan and its metabolites in horses following a single oral administration. Dextromethorphan is an N-methyl-D-aspartate (NMDA) non-competitive antagonist commonly used in human medicine as an antitussive. Dextromethorphan is metabolized in humans by cytochrome P450 2D6 into dextrorphan, which is reported to be more potent than the parent compound. The goal of this study is to describe the metabolism of and determine the pharmacokinetics of dextromethorphan and its major metabolites following oral administration to horses. A total of 23 horses received a single oral dose of 2 mg/kg. Blood samples were collected at time 0 and at various times up to 96 h post drug ad...
Characterization and angiogenic potential of xenogeneic bone grafting materials: Role of periodontal ligament cells. Adequate revascularization is a prerequisite for successful healing of periodontal bone defects. This study characterized three different xenogeneic bone grafting materials: Gen-Os of equine and porcine origins, and anorganic Bio-Oss. We also investigated their angiogenic potential. All materials were composed of poorly crystalline calcium oxide phosphate, with Bio-Oss exhibiting a carbonated phase and larger particle size and both Gen-Os showing the presence of collagen. Both Gen-Os materials significantly enhanced vascular endothelial growth factor (VEGF) secretion by PDL cells. A significan...
Rosiglitazone Improves Stallion Sperm Motility, ATP Content, and Mitochondrial Function. Media used for equine sperm storage often contain relatively high concentrations of glucose, even though stallion spermatozoa preferentially utilize oxidative phosphorylation (OXPHOS) over glycolysis to generate ATP and support motility. Rosiglitazone is an antidiabetic compound that enhances metabolic flexibility and glucose utilization in various cell types, but its effects on sperm metabolism are unknown. This study investigated the effects of rosiglitazone on stallion sperm function in vitro, along with the possible role of AMP-activated protein kinase (AMPK) in mediating these effects. Sp...
Isolation of endothelial colony-forming cells from blood samples collected from the jugular and cephalic veins of healthy adult horses. OBJECTIVE To evaluate optimal isolation of endothelial colony-forming cells (ECFCs) from peripheral blood of horses. SAMPLE Jugular and cephalic venous blood samples from 17 adult horses. PROCEDURES Each blood sample was divided; isolation was performed with whole blood adherence (WBA) and density gradient centrifugation (DGC). Isolated cells were characterized by uptake of 1,1'-dioctadecyl-3,3,3',3'-tetramethylindocarbocyanine perchlorate-labeled acetylated low-density lipoprotein (DiI-Ac-LDL), vascular tubule formation, and expression of endothelial (CD34, CD105, vascular endothelial growth ...
Comparison of the pharmacokinetics of two formulations of hydroxyethyl starch in healthy horses. A lower molecular weight and molar substitution formulation (130/0.4) of hydroxyethyl starch solution has been shown to have a more sustained effect on COP and similar hemodynamic effects as a higher molecular weight and molar substitution formulation (600/0.75) in healthy horses. In humans, these pharmacodynamic characteristics are coupled with more rapid clearance and decreased adverse coagulation effects and accumulation. The objective of this study was to determine and compare the pharmacokinetics of these two formulations in horses. Eight healthy horses were given a 10 mL/kg bolus of eac...
Beta-mercaptoethanol supplementation of in vitro maturation medium does not influence nuclear and cytoplasmic maturation of equine oocytes. In vitro embryo production in the horse is still not as efficient as in other species. Oxidative stress negatively affects oocyte and embryo culture. To attenuate/minimize the oxidative stress, antioxidants such as low-molecular thiol compounds can be added to culture media. Beta-mercaptoethanol (BME) has been shown to improve maturation and embryo development in different species. The aim of this study was to investigate whether the addition to maturation medium of BME at common (0.1 mM) and high (0.7 mM) concentration could improve oocyte maturation also in the horse. Equine oocytes recove...
N-glycosylation proteomic characterization and cross-species comparison of milk fat globule membrane proteins from mammals. Glycosylation of proteins has been implicated in various biological functions and has received much attention; however, glycoprotein components and inter-species complexity have not yet been elucidated fully in milk proteins. N-linked glycosylation sites and glycoproteins in milk fat globule membrane (MFGM) fractions were investigated by combining N-glycosylated peptides enrichment and high-accuracy Q Exactive identification, to map the N-glycoproteome profiles in Holstein and Jersey cows, buffaloes, yaks, goats, camels, horses, and humans. A total of 399 N-glycoproteins with 677 glycosylation...
Evaluation and Comparison of Vitamin D Responsive Gene Expression in Ovine, Canine and Equine Kidney. The aim of this study was to determine the relative abundance and relationship of vitamin D responsive and calcium transporting transcripts (TRPV5, TRPV6, calD9k, calD28k, PMCA, NCX1, CYP27B1, CYP24A1, and VDR) in ovine, canine and, equine kidney using quantitative real-time PCR (RT-qPCR), and then perform a comparison between the three species. Renal tissue samples were harvested post-mortem from 10 horses, 10 sheep, and five dogs. Primers were designed for each gene. For each sample total RNA was extracted, cDNA synthesised, and RT-qPCR was performed. RT-qPCR data were normalised and statist...
Secretory immunoglobulin A and immunoglobulin G in horse saliva. This study aimed to increase the knowledge on salivary antibodies in the horse since these constitute an important part of the immune defence of the oral cavity. For that purpose assays to detect horse immunoglobulin A (IgA) including secretory IgA (SIgA) were set up and the molecular weights of different components of the horse IgA system were estimated. Moreover, samples from 51 clinically healthy horses were tested for total SIgA and IgG amounts in saliva and relative IgG3/5 (IgG(T)) and IgG4/7 (IgGb) content were tested in serum and saliva. Results showed a mean concentration of 74μg SIgA...
Comparison of three different methods for the quantification of equine insulin. Exact analysis of equine insulin in blood samples is the key element for assessing insulin resistance or insulin dysregulation in horses. However, previous studies indicated marked differences in insulin concentrations obtained from sample analyses with different immunoassays. Most assays used in veterinary medicine are originally designed for use in human diagnostics and are based on antibodies directed against human insulin, although amino acid sequences between equine and human insulin differ. Species-specific assays are being used more frequently and seem to provide advantages compared to ...
Chiral Selectivity in Inter-reactant Recognition and Electron Transfer of the Oxidation of Horse Heart Cytochrome c by Trioxalatocobaltate(III). Outer-sphere electron transfer (ET) between optically active transition-metal complexes and either other transition-metal complexes or metalloproteins is a prototype reaction for kinetic chirality. Chirality as the ratio between bimolecular rate constants of two enantiomers mostly amounts to 1.05-1.2 with either the Λ or Δ form the more reactive, but the origin of chirality in ET parameters such as work terms, electronic transmission coefficient, and nuclear reorganization free energy has not been addressed. We report a study of ET between the Λ-/Δ-[Co(Ox)3](3-) pair (Ox = oxalate) and hor...
Dextromethorphan and debrisoquine metabolism and polymorphism of the gene for cytochrome P450 isozyme 2D50 in Thoroughbreds. OBJECTIVE To characterize polymorphisms of the gene for cytochrome P450 isozyme 2D50 (CYP2D50) and the disposition of 2 CYP2D50 probe drugs, dextromethorphan and debrisoquine, in horses. ANIMALS 23 healthy horses (22 Thoroughbreds and 1 Standardbred). PROCEDURES Single-nucleotide polymorphisms (SNPs) in CYP2D50 were identified. Disposition of dextromethorphan (2 mg/kg) and debrisoquine (0.2 mg/kg) were determined after oral (dextromethorphan) or nasogastric (debrisoquine) administration to the horses. Metabolic ratios of plasma dextromethorphan and total dextrorphan (dextrorphan plus dextrorph...
