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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.
Molecular entrapment of small molecules within the interior of horse spleen ferritin. A procedure for trapping small molecules inside the interior of horse spleen ferritin (HoSF) and methods for characterizing HoSF and its small entrapped molecules are described. HoSF is first dissociated into subunits by adjustment to pH 2 in the presence of the small molecules to be trapped. The pH of the dissociated HoSF is then increased to 7 at which time the dissociated subunits reassemble reforming the 24-mer HoSF, thereby trapping solvent within its interior. HoSF is then separated from unbound molecules by dialysis, ultrafiltration, and/or ammonium sulfate precipitation. Sephadex G-25 ...
The dynamics of gonadotrophin-releasing hormone, LH and FSH secretion during the spontaneous ovulatory surge of the mare as revealed by intensive sampling of pituitary venous blood. Conflicting views exist on the mode of gonadotrophin-releasing hormone (GnRH) secretion during the ovulatory LH surge and the relative importance of changes in pituitary responsiveness to GnRH in generating the LH surge. This disagreement may stem from species differences and/or methodological problems. To provide data on the exact relationship between GnRH and gonadotrophin secretion during the spontaneous LH surge, we collected pituitary venous (PV) blood every 30 s for 3-4 h from eight mares and then assayed GnRH (in six of the mares), FSH and LH. Jugular blood was also collected from twelv...
Effects of heparin, venous strangulation obstruction of the small intestine, and reperfusion of the small intestine on plasma diamine oxidase activity in horses. Diamine oxidase (DAO), an enzyme of small intestinal origin, is released from mucosal storage sites by IV administration of heparin, to yield the plasma postheparin DAO (PHD) curve. The PHD curve is diminished when mucosal surface area is lost, and baseline (without heparin) plasma DAO activity increases when mucosal storage sites are damaged. Plasma DAO activity was measured after 2 doses of heparin were administered IV in healthy, conscious horses. In anesthetized horses, the PHD curve was studied: during sham small intestinal surgery, and during venous strangulation obstruction (VSO) of the...
[Effect of the time of sample collection after exertion and the specimen handling on the lactate content in the blood of horses]. The mean maximal lactate concentration of horses after exercise (Lamax) amounted to 4.5 +/- 2.2 mmol/l for gallop workouts of less than 11 m/s and more than 180 s (n = 35; category A), at more than 11 m/s and less than 180 s duration (n = 17; category B) to 16.3 +/- 4.8 mmol/l and at less than 11 m/s and less than 180 s duration (n = 10; category C) to 4.6 +/- 1.6 mmol/l. Lamax was always measured immediately after exercise following exercise of categories A and C. But for exercise bouts of category B Lamax was measured between the first and the tenth minute after exercise. Following exercise ...
[Detection of mycoplasmas in horses with respiratory diseases and their biochemical and serologic characterization]. Tracheal swabs were taken from 25 horses with respiratory diseases and investigated for mycoplasmas using three different media. Mycoplasmas could be isolated from 5 horses. The isolates were characterized by serological and biochemical methods. Four isolates could be identified as Mycoplasma equirhinis. The fifth isolate could not be typed. It did not react with antisera against mycoplasmas found in the respiratory tract of horses and its biochemical characteristics were different from the mycoplasmas described so far. It may represent a new species.
[Examination of the ovarian activity of mares using progesterone profiles]. By means of clinical and analytical procedures (enzyme immuno assay for progesterone with microtiterplate method) the ovarian activity from 27 mares was tested over a period of several weeks. The measurement of the progesterone level to determine the time of ovulation was proved as suitable in the period of 1-2 days after ovulation. In normocyclic mares (n = 17) a different development of the progesterone profile was detected, so that an insufficient development of the corpus luteum (35%) could be considered. By means of continuous measurement of progesterone (> or = 30 days) six of ten mar...
Application to cows and horses of Spotchem, a dry-chemistry blood analyzer for use in veterinary clinics. The usefulness of a dry-chemistry blood analyzer, Spotchem SP-4410 (SP-4410) in a veterinary clinic for analysis of bovine and equine blood chemistry was studied. We quantitated total protein (TP), albumin (Alb), total bilirubin (T-Bil), blood urea nitrogen (BUN), total cholesterol (T-Cho), glucose (Glu), calcium (Ca), aspartate aminotransferase (AST), gamma-glutamyltransferase (GGT), creatinine phosphokinase (CPK), and alkaline phosphatase (ALP) in bovine sera. Each sample was assayed with both the SP-4410 and an automated blood analyzer which served as a wet-chemistry reference system, and t...
Kinetic evaluation of muscle damage during exercise by calculation of amount of creatine kinase released. To quantify the extent of muscle alteration during prolonged exercise, the release rate of creatine kinase (CK) from striated muscle was measured in six horses during a rest period (6 h) and during three exercise tests (15, 30, and 60 km) at a constant speed of 200 m/min. CK clearance was measured after intravenous bolus administration (150 U/kg) of a CK solution obtained from horse muscle. The CK steady-state volume of distribution was 0.059 +/- 0.0215 l/kg, the terminal half-life was 123 +/- 28 min, and the plasma clearance was 0.36 +/- 0.10 ml.kg-1 x min-1. After an intramuscular CK adminis...
Structure determination of the disialylated poly-(N-acetyllactosamine)-containing O-linked carbohydrate chains of equine chorionic gonadotropin. The disialylated poly-(N-acetyllactosamine)-containing O-linked oligosaccharide alditols, released by alkaline borohydride treatment of the enzymically N-deglycosylated beta-subunit of equine chorionic gonadotropin, were purified by fast protein liquid chromatography (FPLC) on Mono Q and analysed by fast ion bombardment mass spectrometry (FAB-MS) and 1H-NMR spectroscopy. The identified oligosaccharide alditols have the following structure: [Formula: see text]
Preparation and characterization of monoclonal antibodies against equine chondrocytes, osteoblasts and osteocytes. Three monoclonal antibodies capable of individually recognizing chondrocytes, osteoblasts and osteocytes were prepared. EB-1 reacted with a 55-kDa antigen on the chondrocyte membrane, EB-2 with a 110-kDa antigen on the membrane of osteoblasts and/or partial osteocytes, and EB-3 with a 130-kDa antigen on the membrane of osteocytes. These monoclonal antibodies may be useful probes for studying the differentiation and maturation of osteogenic cells.
The molecular weight of therapeutic hyaluronan (sodium hyaluronate): how significant is it? Various molecular weight hyaluronic acid (HA) preparations have been injected into joints for the treatment of human and equine osteoarthritis. A therapeutic advantage has been claimed for commercial products with a molecular weight in the range found in normal synovial fluid (SF), compared to lower molecular weight products. But a correlation between molecular weight and efficacy is not borne out by an analysis of the available literature on clinical results. SF viscosity, HA concentration, HA molecular weight and rate of synthesis in joint disease. It is proposed that the beneficial effect o...
Effect of oxytetracycline on metacarpophalangeal and distal interphalangeal joint angles in newborn foals. Thirty-five newborn foals were assigned to 1 of 3 groups and treated with 0.9% NaCl solution (saline; group 1; n = 12), oxytetracycline (44 mg/kg of body weight; group 2; n = 12), or 2-pyrrolidone (oxytetracycline vehicle; group 3; n = 11) in saline solution during the first 36 hours after birth. Serum biochemical analyses were performed on samples obtained from group-1 and group-2 foals before treatment and 24 and 96 hours after treatment. Lateral to medial radiographic views of the forelimbs were obtained before treatment and 24 and 96 hours after treatment in all foals. Metacarpophalangeal ...
Investigation of the metabolism of azaperone in the horse. Urine samples collected from a horse after intramuscular administration of 40 mg of azaperone were extracted at pH 10 before and after acid hydrolysis. The extracts were concentrated and analysed by LC-MS-MS. Two N-dealkylated metabolites, N-despyridinylazaperol and N-despyridinylazaperone, and a low concentration of azaperone were detected in the unhydrolysed urine. Six metabolites; hydroxyazaperol, two hydroxyazaperones, azaperol, N-despyridinylazaperol and N-despyridinylazaperone were detected in the hydrolysed urine extracts. Using XAD-2 resin extraction, three glucuronide conjugated azape...
Serum hypoxanthine and xanthine concentrations in horses heterozygous for combined immunodeficiency. A group of diseases termed combined immunodeficiency (CID) results in a severe form of immunodeficiency. While CID in humans has two genetics bases, in Arabian it is inherited in an autosomal recessive manner. Kettler et al. (1989) determined that uric acid was significantly (p 0.05) between carrier and non-carrier horse's serum levels of hypoxanthine or xanthine. These data, combined with our previous ones suggest that an enzymatic lesion in the purine salvage pathway may occur at the urate oxidase step. ZUSAMMENFASSUNG: Serum-Hypoxanthin- und -Xanthin-Spiegel in Pferden mit Heterozygotie fÃ...
Follicular fluid lipoproteins in the mare: evaluation of HDL transfer from plasma to follicular fluid. Using a density gradient ultracentrifugal procedure, we have separated equine plasma and follicular fluid high-density lipoproteins (HDL). The density distribution of the follicular fluid HDL was clearly displaced towards the highest densities in comparison with that of plasma HDL. Similarly, an analysis of size distributions showed a decrease in follicular fluid HDL diameters (4.2 to 9.2 nm) compared to plasma HDL (5.5 to 9.5 nm). HDL were isolated into three subfractions on the basis of the disposition of the Sudan Black stained bands in the centrifuge tubes. Concentrations of each subfracti...
Cellular sources of proteolytic enzymes in equine joints. Isolated equine blood and articular cells were investigated for proteolytic enzyme production by means of gel filtration and analysis on 14C-acetylated collagen and casein substrates. Significant amounts of collagenase and caseinase activity were produced by cultured synoviocytes stimulated with equine interleukin 1, although large amounts of collagenase also originated from neutrophils.
Age-related storage of iron in the liver of horses. The non-haem iron concentration was estimated in post-mortem liver samples from 51 horses (age range 1-25 years). Two were normal and 49 had been suffering from conditions that were not expected to have had long-term effects on iron metabolism. Muscle samples (splenius and biceps femoris) from 23 of these horses were also analysed. There was a highly significant age-related increase in the non-haem iron concentration in the liver (r = 0.635, p < 0.001), but not in the muscles, in which the iron concentration was much lower than in the liver.
Binding of epidermal growth factor and transforming growth factor-alpha in mammalian preimplantation embryos. Preimplantation embryos of the pig (Days 11 to 15), cow (Days 14 to 16), sheep (Day 14) and pony (Day 16) bind epidermal growth factor (EGF) specifically. Binding was not detected in embryos of the rabbit at Day 5 or 6 or the hamster at Day 3. Transforming growth factor-alpha displaced [(125)I] EGF in pig, cow and pony embryos almost as much as unlabeled EGF. The binding affinities of EGF ranged from 12 to 233 pM in pig and cow embryos. The range of species and binding features indicate that the EGF family may play a significant role in mammalian preimplantation development.
The equine placenta and equine chorionic gonadotrophin–an overview. Chorionic gonadotrophins seem to be unique for primate and equid species. Unlike primates, the equine conceptus does not implant in the maternal uterine endometrium until around day 37 of pregnancy. At this time specialized cells of the trophoblast, organized in the embryonic girdle, invade the endometrium and become established in the endometrial stroma, forming the so-called endometrial cups. This migration of girdle cells is accompanied by their morphological transformation into large decidual-like cells and by the appearance of a gonadotrophic hormone in the mare's blood. There is convinci...
The role of sweat in maintaining the stimulation of effort homeostasis in horses. Sweat secretion was analyzed quantitatively and qualitatively in 20 horses after a 5 min. gallop at 450 m/min. The analysis revealed concentration of proteins 63.3 +/- 6.47 g/l, mainly albumins, a high level of sodium 254.43 +/- 62.84 mM/,l chloride 268.68 +/- 98.46 mM/l, potassium 98.95 +/- 49.62 mM/l and calcium 4.14 +/- 0.8 mM/l. A dependence was found between the protein concentration in serum and its quantity in sweat and between the level of potassium in sweat and its loss from the cells within a range 8.6 to 25.8 mM/l. The hypertonic horse sweat protects organism for excessive water los...
Proteolytic enzymes in equine joints with infectious arthritis. Significant amounts of collagenase and caseinase activity were detected in infected synovial fluid samples. Partial characterisation of the enzymes by gel filtration suggested that synovial fluid from cases of infectious arthritis may contain enzymes from both the synovial cells and neutrophils. This finding was also supported by analysis of sequential synovial fluid samples from 4 infected joints. In 3 joints the concentration of caseinase and in 1 joint collagenase paralleled the decline in total nucleated cell count. However, in 3 joints the concentration of collagenase remained high after ...
Metallothionein in platelets. The zinc content in platelets from rabbits, humans and horses was determined, and the levels of zinc were found to be significantly higher (3 micrograms/10(10) cells) than those in other peripheral blood cells. About 70% of the zinc in the supernatants of platelet lysates could be detected. From the results of gel filtration analysis, the zinc in platelet lysates was found to be bound with a low-molecular-weight protein (MW 6,000-8,000) detected as metallothionein (MT) on the basis of antigenic properties determined by enzyme-linked immunoassay and immunoblotting analysis using monoclonal anti...
Caffeine clearance in the horse. The pharmacokinetic properties of intravenously administered caffeine were studied in 10 horses using a commercially available automated enzyme immunoassay. The harmonic mean for the distribution half-life was 5.2 min (range 1.4-18.7). The harmonic mean for the elimination half-life was 10.18 h (range 6.82-20.92). The harmonic mean of the volume of distribution was 0.32 L/kg (range 0.22-0.53). There was no correlation between the dose of caffeine/kg body weight and the elimination half-life (Spearman's coefficient of rank correlation = 0.19).
Quantitative analysis of cyanogen bromide-cleaved peptides for the assessment of type I: type II collagen ratios in equine articular repair tissue. Cyanogen bromide was used to solubilise and specifically fragment purified equine Type I and II collagen and equine articular surface repair tissue. The resultant peptides were separated by sodium dodecyl sulphate-polyacrylamide gel electrophoresis and quantified by densitometric scanning. Measurement of the relative amounts of the peptides alpha 2(I) CB3, 5 and alpha 1(II)CB10 provided an accurate method of establishing the ratio of Type I to Type II collagen in mixtures of purified equine collagens. The method was sensitive to 6% Type II collagen when the band areas were corrected for peptid...
Secretagogue-induced [14C]aminopyrine uptake in isolated equine parietal cells. Equine oxyntic mucosal cells were obtained by sequential exposure to pronase and collagenase. Acid production by parietal cells was assessed by uptake of [14C]aminopyrine (AP), a weak base that accumulates in intracellular acidic spaces. Incubation for various times revealed a maximal AP uptake at 10 minutes for histamine and carbachol. Similar secretagogue responses were observed for parietal cells from the mucosal cell preparation or after enrichment by elutriation. Histamine and isobutyl-methylxanthine (IBMX) stimulated AP uptake with a dose-dependent response and maximal effective concentr...
