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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.
Studies related to the metabolism of anabolic steroids in the horse: the identification of some 16-oxygenated metabolites of 19-nortestosterone. 1. The metabolism of 19-nor[4-14C]testosterone in a thoroughbred horse has been studied and neutral urinary metabolites obtained after enzyme hydrolysis have been investigated by g.l.c.-mass spectrometry. 2. 3-Hydroxyestran-17-one, 17 alpha- and 17 beta-nortestosterone, estrane-3,17-diol (two isomers), 3,16-dihydroxyestran-17-one (two isomers), 3,17-dihydroxyestran-16-one (two isomers) and estrane-3,16,17-triol were identified in the neutral urinary extracts.
Changes in blood gas, acid-base and metabolic parameters in horses during three-day event competition. Sixteen horses competing in a three-day event had venous blood samples collected during the speed and endurance test (day 2) to examine changes in blood gas ands acid-base balance, and the concentrations of lactate, pyruvate, beta-hydroxybutyrate, acetoacetate, alpha-ketoglutarate and cortisol. Following the roads and tracks and steeplechase phases there was a significant metabolic and respiratory alkalosis despite a rise in lactate. After completion of the cross country section, although there was a significant decrease in total base, there was no significant change in pH from pre-event value...
Skin surface lipids of the horse. Skin surface lipids from the sides of male and female horses (Equus caballus) were collected in acetone and analyzed by thin layer chromatography and gas liquid chromatography. The sole components in both sexes were cholesterol, cholesteryl esters and the lactones of 32-, 32- and 36-carbon omega-hydroxy acids, each including a methyl group in the n-1 position. Most of the lactones were monounsaturated (either n-8 or n-10), but small amounts of saturated and dienoic species were present. A pooled sample of the skin surface lipids contained 14% cholesterol, 38% cholesteryl esters and 48% lactone...
Biochemical characterization of equine herpesvirus type 3-induced deoxythymidine kinase purified from lytically infected horse embryo dermal fibroblasts. Infection of horse KyED cells with equine herpesvirus type 3 (EHV-3) resulted in a sevenfold increase in cytosol deoxythymidine kinase (dTK) activity. The EHV-3 dTK was purified from KyED cytosol dTK by affinity chromatography on deoxythymidine-Sepharose and characterized with respect to its electrophoretic mobility, molecular weight, substrate specificity, phosphate donor specificity, and immunological specificity. The purified EHV-3 dTK migrated in polyacrylamide gels with an Rf of 0.30 and sedimented in glycerol gradients with an S value of 5.13, corresponding to a molecular weight of 83,00...
Biochemical effects of succinylcholine chloride in mechanically ventilated horses anesthetized with halothane in oxygen. Succinylcholine chloride administered to horses anesthetized with halothane in oxygen and mechanically ventilated, caused slight but statistically insignificant (P less than 0.01) increases in creatine phosphokinase, lactic dehydrogenase, and aspartate aminotransferase activity. The increases in these enzymes have been explained on the basis of muscle damage resulting from succinylcholine chloride induced muscle fasciculations and by hypoperfusion of tissues due to depression of the cardiovascular system caused by general anesthesia. These changes were not clinically apparent based upon the ab...
The effect of trypsin digestion on the structure and iron-donating properties of transferrins from several species. The effect of trypsin digestion on iron-saturated and iron-free (apo) human, rabbit, bovine, pig and horse tranferrins has been studied. Iron-binding fragments were produced only from iron-saturated pig and bovine transferrins although some cleavage of the polypeptide chain occurred in all cases. The apo-transferrins were generally degraded to a greater extent than the corresponding iron-saturated proteins. The ability of the different transferrins to donate iron to rabbit reticulocytes varied in the order rabbit approximately pig greater than human approximately horse greater than bovine. Try...
Renin, aldosterone and cortisol in the thoroughbred horse. To assess the renin-aldosterone system in a large mammal, simultaneous morning activities of plasma renin and concentrations of aldosterone and cortisol were measured in 25 thoroughbred horses. Renin was relatively low in all horses (0.16 +/- 0.02 (S.E.M.) ng angiotensin I/ml per h), levels of aldosterone in plasma were 527 +/- 130 pmol/1 and levels of cortisol in plasma were 141 +/- 11 nmol/l. Levels of aldosterone were significantly correlated with levels of renin in all horses (r = 0.62, P less than 0.001) but not with those of cortisol, and renin was negatively correlated with age in male ...
The immunological approach to pregnancy diagnosis: a review. The developing embryo/fetus bears antigens which are foreign to the mother and it could be expected that immune rejection of the conceptus would occur. One of the reasons why the fetus is not rejected is because a depression of the maternal immune response takes place during pregnancy. Serum from pregnant animals of several species has been shown to contain a factor, early pregnancy factor (EPF), which is immunosuppressive. EPF has been detected as early as six hours after mating and its detection could aid diagnosis of early pregnancy in all species.
Involvement of lysines-72 and -79 in the alkaline isomerization of horse heart ferricytochrome c. Spectrophotometric titrations of five singly modified horse heart ferricytochromes c, specifically (trifluoromethyl)phenylcarbamylated (CF3PhNHCO-) or trifluoroacetylated (CF3CO-) at lysines-13, -72, and -79, were carried out. The CF3PhNHCO-Lys-13, Lys-79, and CF3CO-Lys-79 derivatives all underwent alkaline isomerization with loss of the 695-nm band to low-spin species with an apparent pK of about 8.9, as did the unmodified cytochrome. However, modification of lysine-72 appeared to alter the reaction pathway since the CF3PhNHCO-Lys-72 derivative isomerized to a high-spin form with an apparent ...
Purification by affinity chromatography and characterization of a neutral alpha-glucosidase from horse kidney. A horse kidney neutral alpha-D-glucosidase (alpha-D-glucoside glucohydrolase, EC 3.2.1.20) was purified about 580-fold with a yield of 33% by an affinity chromatography technique using the p-aminophenyl-beta-D-maltoside, a substrate derivative, as ligand. The purified enzyme, homogeneous in polyacrylamide gel electrophoresis, was a glycoprotein with a molecular weight of 280 000 as calculated by gel filtration and its isoelectric focusing points was found to be pH 4.1. The purified enzyme was able to hydrolyze various substrates having (alpha-1,2), (alpha-1,3), (alpha-1,4), and (alpha-1,6) glu...
Urinary excretion of arsenic from horses injected with an organic arsenical compound. Five doses of sodium cacodylate (194 mg) were administered intravenously to two horses at two-day intervals. The arsenic content of daily urine samples was determined for five days after the final dose, by which time urinary arsenic concentrations were close to those of control samples. It was considered that these results reflected a common property of organic arsenicals viz. more rapid excretion by mammals than is the case with inorganic arsenic compounds.
Effect of dehydrocholic, chenodeoxycholic, and taurocholic acids on the excretion of bilirubin. The effects of IV bile acid infusion (at approx 20% of normal excretion rate) on the biliary excretion of 3-alpha-hydroxy bile acids and bilirubin were investigated in ponies prepared surgically with chronic external biliary fistulas. Endogenous bile acid excretion (approx 45 mumol/min) decreased to the hepatic synthesis rate (approx 1.5 mumol/min) during the initial 4 to 5 hours of bile drainage. In type 1 studies, both chenodeoxycholic and taurocholic acid infusion (8 to 9 mumol/min) increased bilirubin excretion by 58% to 82% following 5 hours of biliary diversion. During type 2 studies, 3-...
Methylation of histidine-48 in pancreatic phospholipase A2. Role of histidine and calcium ion in the catalytic mechanism. It is known that His-48 is part of the active center in pancreatic phospholipase. To further elucidate the role of histidine-48 in the active center of pancreatic phospholipase A2, we have modified the enzyme with a number of bromo ketones and methyl benzenesulfonates. Rapid methylation occurred with methyl p-nitrobenzenesulfonate. Methylated phospholipase shows total loss of enzymatic activity whereas binding of substrate and the cofactor Ca2+ remains intact. Amino acid analysis of methylated equine phospholipase showed the loss of the single molecule of histidine and the formation of one mol...
Further studies on gangliosides of erythrocytes from horses and cattle. The ganglioside patterns of erythrocytes from individual horses and cattle were examined. Variations in the ganglioside patterns were found in both horses and cattle. In the erythrocytes of most horses examined, NeuGc-Gal-Glc-ceramide (NeuGc-GM3) of 25 horses examined had only NeuGc-GM3 with no 4-O-Ac-NeuGc-GM3. The erythrocytes of various breeds of cattle had a characteristic ganglioside pattern, but they could be divided into 4 types on the basis of the composition of their gangliosides.
Energy and current requirements for ventricular defibrillation using trapezoidal waves. The threshold energy and current required for ventricular defibrillation was determined in dogs ranging in weight from 6.4 to 38 kg and in ponies ranging in weight from 40 to 101 kg. Trapezoidal waves, 10 ms in duration, with 10%, 50%, 70%, and 90% tilt were applied to transchest electrodes. For all values of tilt, the energy and current required increased with body weight. The energy dose (joules per kilogram of body weight) was higher for the heavier animals, whereas the current dose (peak amperes per kilogram of body weight) was essentially the same for dogs and ponies. In both species and ...
Copper-induced GSH depletion and methaemoglobin formation in vitro in erythrocytes of some domestic animals and man. A comparative study. Reduced glutathione (GSH), per cent methaemoglobin and haemolysis were measured in physiologic saline suspensions of erythrocytes from sheep, goat, cattle, horse, swine and man; incubated for 24 hours at 37 degrees with and without copper sulphate (0,5 and 10 micrograms Cu/ml suspension). Formation of Heinz bodies was studied in similar experiments with sheep and swine cells only. Generally, GSH depletion developed first, followed by methaemoglobinemia and Heinz bodies, while haemolysis was limited. Both spontaneous and copper-induced GSH depletion was slow in swine erythrocytes compared to ot...
Comparative studies of alpha-lactalbumin and lysozyme: the proteins of kangaroo (Megaleia rufa and Macropus giganteus) and horse (Equus caballus). As part of a study of the 'whey' proteins of various mammals, a comparison is made of the alpha-lactalbumins and lysozymes of the kangaroo and horse. In the milk of the red kangaroo (Megaleia rufa) there is only one alpha-lactalbumin and it occurs throughout lactation, but no lysozyme has been detected. There are two alpha-lactalbumins in the milk of the grey kangaroo (Macropus giganteus), one, designated alpha-lactalbumin Zone B, is present throughout lactation; the second, designated alpha-lactalbumin Zone A, is present only in late lactation. One lysozyme is also present. The milk of the ho...
Variation of acidic prealbumins in the donkey (Equus asinus). Starch gel electrophoresis of 55 donkey serum samples revealed three prealbumin (Pr) phenotypes temporarily designated Pr M, Pr MT and Pr T. The distribution was in agreement with a genetic theory of two codominant alleles of frequencies, PrM = 0.87 and PrT - 0.13. Variation was also observed for proteins migrating with the same rate as the Xh zones in the horse.
[Bacteriological studies of Haemophilus equigenitalis Taylor 1978, the causative organism of contagious equine metritis 1977 (author’s transl)]. The cultural, biochemical, antigenic and antibiotic susceptibility characteristics of 17 strains of Haemophilus equigenitalis, the causative organism of contagious equine metritis (CEM), were studied. Biochemical characteristics were investigated using both conventional method and the API ZYM system of enzyme detection. The biochemical profile of the H. equigenitalis strains was unique and differed from the other bacterial species studied under the same experimental conditions (H. influenzae and H. parainfluenzae, B. abortus and B. melitensis, P. multocida, A. calcoaceticus). The required X an...
Serum quality: an analysis of its components. Foetal and new born bovine sera, horse serum, human serum and human plasma, and protein solutions prepared from the by-products of human plasma fractionation have been analysed. Foetal bovine sera were found to have lower total protein (g/l) and % of gamma-globulin than the other sera studied while the potassium (mmol/1) was higher. Protease inhibitors could be detected in all specimens tested.
A new method for the isolation of aminoacylase from mammalian kidneys. Aminoacylase (E.C. 3.5.1.14) was isolated from the kidneys of different mammalian species (horse, cattle, rabbit and pig) by extracting the organ with water and subjecting the extract to heat treatment at 70 degrees C for 10 min, then, after having removed denatured proteins by fractionating those remaining in the solution by ammonium sulfate. The enzyme obtained in this way can either be used directly for practical purposes (e.g. preparation of immobilized aminoacylase) or further purified by chromatography. For the further purification of porcine kidney aminoacylase we applied a combination ...
