The physiology of horses encompasses the study of the biological functions and processes that occur within the equine body. This includes the examination of various systems such as the cardiovascular, respiratory, musculoskeletal, digestive, and nervous systems. Understanding equine physiology is essential for comprehending how horses adapt to different environmental conditions, perform physical activities, and respond to health challenges. Research in this field often focuses on the mechanisms of energy metabolism, thermoregulation, and muscle function during exercise, as well as the physiological responses to stress and disease. This page compiles peer-reviewed research studies and scholarly articles that explore the diverse aspects of equine physiology, providing insights into the biological processes that support the health and performance of horses.
Hinckley KA, Fearn S, Howard BR, Henderson IW.Laminitis, a microvascular disease of the equine hoof leads to severe lameness. Exogenous iv 1-arginine and transdermal nitric oxide donors, such as GTN, applied to the pasterns improve lameness during acute laminitis. Near Infrared spectroscopy in an earlier study showed haemostasis and ischaemia in the hoof during acute laminitis, both were alleviated by 1-arginine. Quantitative NIRS in the present study shows that transdermal GTN increases blood flow in the equine hoof. It is concluded that glyceryl trinitrate enhances nitric oxide mediated perfusion within the equine hoof in normal and chr...
Ball BA.There are considerable differences between mammalian species in the distribution and activity of ciliated cells within the oviduct, and limited information is available concerning either the distribution or activity of cilia within the equine oviduct. Patterns of ciliary activity were characterized in the ampulla and isthmus of oviducts recovered at 2 d after ovulation from 10 mares, and scanning electron microscopy was used to examine regional differences in the distribution of cilia in oviducts from 3 of these mares. Based upon the motility of 15 microm latex microspheres, ciliary activity w...
Marshall DE, Dumasia MC, Wooding P, Gower DB, Houghton E.Maternal endometrial and fetal allantochorionic tissues were separated manually from the placentae of seven healthy thoroughbred and three pony mares, ranging in gestational age from 100 to 318 days. The homogeneity of subcellular fractions prepared from these tissues was assessed initially using the marker enzymes, succinate dehydrogenase, NADPH cytochrome C reductase and lactate dehydrogenase for the mitochondrial, microsomal and cytosolic fractions, respectively. Light microscopy and histochemical analysis demonstrated that the separated fetal allantochorionic membrane, which is made up of ...
Chaffin MK, Matthews NS, Cohen ND, Carter GK.A commercially available pulse oximeter was evaluated in anaesthetised foals to determine its accuracy for estimating arterial haemoglobin saturation (SaO2). Five different transducer/transducer attachment site (TTAS) combinations were evaluated; 1-3) a fingertip transmission transducer attached to the foal's ear, lip and tongue, 4) an adhesive transmission transducer positioned on the foal's ear and 5) a forehead reflectance transducer placed on the ventral aspect of the foal's tail-base. Eight normal, Quarter Horse foals (age 5-10 days) were studied while under general anaesthesia. Alteratio...
Dobrinski I, Ignotz GG, Thomas PG, Ball BA.To test the hypotheses that the attachment of equine spermatozoa to uterine tubal (oviductal) epithelial cells (OEC) in vitro is mediated by glycoproteins, and that proteins with carbohydrate-binding properties are present in the periacrosomal plasma membrane of equine spermatozoa. Methods: 4 reproductively sound stallions, and 1 mare in estrus. Methods: In experiment 1a, fluorescent-labeled spermatozoa were cocultured with monolayers of OEC in the presence of 50 mM glucose, fructose, galactose, mannose, N-acetyl glucosamine, N-acetyl galactosamine, or N-acetyl neuraminic acid, or 10 mg of fet...
Hancke J, Burgos R, Cáceres D, Brunetti F, Durigon A, Wikman G.Sport horses with long lasting high levels of gamma Glutamiltransferase (gGT) and Glutamic Oxalacetic Transaminase (GOT) and Creatinine Phosphokinase (CPK) and poor performance were administered during 14 days 3 g of Caval D'Or®, a standardized dried extract of Schizandra chinensis (fructus) orally. At day "0" the horses were divided into two groups: group 1 received a placebo and group 2 received Caval D'Or®. The results showed that Caval D'Or® is able to reduce significantly the levels of gGT and GOT in the serum at day 7 and 14 after administration. The CPK levels were also reduced by da...
Sysel AM, Pleasant RS, Jacobson JD, Moll HD, Modransky PD, Warnick LD, Sponenberg DP, Eyre P.Amphotericin B-induced synovitis of the left tarsocrural joint was used to create a grade 3 of 4 lameness in 11 horses. Caudal epidural catheters were placed and advanced to the lumbosacral region. Baseline heart and respiratory rates were recorded and horses were videotaped at a walk and trot. Morphine sulphate (0.2 mg/kg) and detomidine hydrochloride (30 micrograms/kg) were administered to treated horses (n = 8) through the epidural catheter; an equivalent volume of physiologic saline solution was administered to control horses (n = 3) through the catheter. At hourly intervals after epidural...
Tyler CM, Golland LC, Evans DL, Hodgson DR, Rose RJ.Thirteen standardbred horses were trained as follows: phase 1 (endurance training, 7 wk), phase 2 (high-intensity training, 9 wk), phase 3 (overload training, 18 wk), and phase 4 (detraining, 12 wk). In phase 3, the horses were divided into two groups: overload training (OLT) and control (C). The OLT group exercised at greater intensities, frequencies, and durations than group C. Overtraining occurred after 31 wk of training and was defined as a significant decrease in treadmill run time in response to a standardized exercise test. In the OLT group, there was a significant decrease in body wei...
Merritt AM, Burrow JA, Horbal MJ, Madison JB, Tran T.To better characterize the source of the large nonparietal secretory response to pentagastrin (PG) expressed in gastric contents of cannulated horses. Methods: Adult cross-bred horses: 4 geldings and 1 mare. Methods: Horses were prepared by surgical insertion of a silastic gastric cannula from which gastric contents after feed was withheld could be continuously collected by gravity drainage. During experiments, the horses were lightly restrained in stocks, the gastric cannula was opened, and a catheter was inserted into a jugular vein. Over the next 5 hours, gastric contents were collected in ...
Caron JP, Tardif G, Martel-Pelletier J, DiBattista JA, Geng C, Pelletier JP.To determine whether matrix metalloprotease 13 (MMP-13; collagenase 3) is produced by equine chondrocytes and to investigate modulation of its expression by recombinant human interleukin 1 beta (rhIL-1 beta) and corticosteroids. Methods: Equine chondrocytes in monolayer culture were stimulated with rhIL-1 beta. Total RNA was extracted, purified, and reverse transcribed into DNA. Using appropriate primers, a putative MMP-13 fragment was amplified by polymerase chain reaction, and cloned into a bacterial vector. The resultant fragment was purified and sequenced, then was used to prepare a digoxi...
Watson ED, Thomson SR.Aromatase P-450 (P-450arom) is a crucial regulatory enzyme that is necessary for conversion of androgens to oestrogens. Corpora lutea and follicles were obtained from the ovaries of cyclic mares and from mares at day 20 and days 40-70 of pregnancy. The presence of P-450arom within specific cell types was investigated by immunostaining to determine potential sites of oestrogen synthesis. Immunoreactivity for P-450arom was confined to the granulosa layer of non-atretic follicles > 5 mm in diameter and to corpora lutea at all stages of the oestrous cycle and during pregnancy. These findings co...
Smith BL, Jones JH, Hornof WJ, Miles JA, Longworth KE, Willits NH.Stress associated with road transport is believed to be a significant contributor to the pathogenesis of post transport respiratory disease in horses. To determine the effects of road transport on pulmonary function, pulmonary aerosol clearance rates were measured in 4 horses 24 h before, and immediately after, 24 h of road transport by delivering aerosolised 99mtechnetium-labelled diethylenetriaminepentacetate (99mTc-DTPA) to the lungs and monitoring its washout. Each horse was transported twice, once while the trailer was equipped with a leaf-spring suspension and bias-ply tyres (trailer's o...
Sharma AK, Kathikeyan S, Kaur P, Singh TP, Yadav MP.Lactoferrin is an iron-binding glycoprotein with a molecular weight of 80 kDa. The protein has two iron binding sites. It has two structural lobes, each housing one Fe(3+) and the synergistic CO(3)(2-) ion. The protein was isolated from the colostrum/milk of mares maintained at National Research Centre on Equines, Hisar, India. The purified samples of the protein were crystallized using a microdialysis method. The protein was dialysed against low ionic strength buffer solution. Several crystal forms were obtained, out of which three were characterized which have cell dimensions as follows. For...
Gastal MO, Gastal EL, Kot K, Ginther OJ.The temporal relationships among day of conceptus fixation (cessation of mobility), conceptus diameter, uterine tone, uterine contractility, and myometrial and endometrial thickness of the middle and caudal segments of the uterine horns were assessed in 13 pony mares with fixation in the caudal segment of a uterine horn. The mean day of fixation (14.9 +/- 0.3) was established by 2-h mobility trials. Uterine tone increased (P < 0.0001) gradually over Days 11 to 21, whereas uterine contractility decreased (P < 0.0001) between Days 14 and 18. The diameter of the spherical embryonic vesicle ...
Cheng FP, Fazeli A, Voorhout WF, Marks A, Bevers MM, Colenbrander B.Peanut agglutinin (PNA) was used to assess the sperm acrosomal status and the acrosome reaction during gamete interaction in the equine species. PNA exclusively binds to the outer acrosomal membrane of stallion spermatozoa, as was established by transmission electron microscopy. Fluorescein isothiocyanate-PNA (FITC-PNA) labeling was used to monitor sperm acrosomal changes during a prolonged incubation period of 24 hours and during a 2-hours incubation in the presence of 5 microM calcium ionophore A23187. In addition, after a 4-hours preincubation in SP-TALP medium, sperm samples were incubated...
Kallio PT, Tsai PS, Bailey JE.Expression of a gene encoding hemoglobin (VHb) from the aerobic bacterium Vitreoscilla sp. in several organisms, including Escherichia coli, has been shown to improve microaerobic cell growth and enhance oxygen-dependent product formation. The suitability of VHb to enhance microaerobic metabolism has been suggested to depend on its unusual oxygen binding characteristics. To examine whether hemoproteins of other origins can also elicit the positive effects VHb exerts in microaerobic E. coli cells, we subcloned the genes encoding Vitreoscilla VHb, horse heart myoglobin (HMb), and yeast flavohemo...
Research in microbiologyNovember 1, 1996
Volume 147, Issue 9 687-696 doi: 10.1016/s0923-2508(97)85116-9
Douet JP, Castroviejo M, Dodin A, Bébéar C.The haemolytic action of 125I-labelled thermostable direct haemolysin from Vibrio parahaemolyticus was studied on human and equine erythrocytes. In the first step, the haemolysin bound to the membranes of both erythrocyte species. This binding seemed temperature-independent. Then, for human erythrocytes, haemolysin produced cell disruption, and haemoglobin was released. Following this step, haemolysin was also released in a temperature-dependent manner. In contrast, equine erythrocytes were not disrupted, and no release of haemolysin occurred. The receptors of labelled haemolysin were analysed...
Kato H, Youn HY, Ohashi T, Watari T, Goitsuka R, Tsujimoto H, Hasegawa A.Using lipopolysaccharide (LPS)-stimulated equine peripheral blood mononuclear cell (PBMC) cDNA as a template, we performed polymerase chain reaction (PCR) amplification with equine interleukin-1 beta (IL-1 beta) specific primers. Electrophoresis of the PCR product on agarose gel revealed an additional smaller fragment that hybridized with an equine IL-1 beta cDNA probe. Sequencing of this fragment demonstrated that it was shorter than normal equine IL-1 beta cDNA by 162 nucleotides, which corresponded to exon 5 of the human and murine IL-1 beta genes. The deletion of 162 nucleotides did not re...
Hoshino M, Kawata Y, Goto Y.GroEL interacts with proteins in denatured states and promotes their efficient folding. To understand the conformational features required for the substrate, we studied the interactions of GroEL with various derivatives of horse cytochrome c including porphyrin-cytochrome c, apo-cytochrome c, and the three fragments containing the heme group, i.e. fragments 1-65, 1-38 and 11-21. Size-exclusion chromatography was performed, taking advantage of the heme absorption of the fluorescence label. Under low-salt conditions, significant binding to GroEL was observed for porphyrin-cytochrome c, apo-cytoc...
Yamashita K, Yonezawa K, Izumisawa Y, Kotani T.The antagonistic effects of atipamezole (20, 40, 60, 80, and 100 micrograms/kg i.v.) on medetomidine (10 micrograms/kg i.v.)-induced sedation were evaluated in horses. Although 20 and 40 micrograms/kg of atipamezole were not sufficient to reverse the sedation, 60 micrograms/kg did effectively reverse the sedation. Atipamezole at 80 micrograms/kg was more potent, and significantly shortened the duration of sedation without any apparent side effects, but a higher dose of 100 micrograms/kg was not more effective than 80 micrograms/kg. The possible use of atipamezole as a reversal agent may enhanc...
Ainsworth DM, Eicker SW, Nalevanko ME, Ducharme NG, Hackett RP, Snedden K.Horses chronically-instrumented with costal diaphragmatic electromyographic electrodes were studied during exercise while unencumbered by a breathing mask. Exercise-associated changes in esophageal (Pes), gastric (Pga) and transdiaphragmatic (Pdi) pressures were measured and related to diaphragmatic electromyographic activity (CS EMG) and to left forelimb impact. In all breaths examined, CS EMG always coincided with decrements in Pes. For all exercise trials, linear increases in CS EMG, Pga and Pdi and linear decreases in Pes, as a function of exercise intensity, always occurred. During all ga...
Van Hoogmoed L, Snyder JR, Christopher M, Vatistas N.To characterize, in mares, changes in peritoneal fluid that occurred within the first 7 days after routine foaling. Methods: Prospective observational trial. Methods: 15 mares. Methods: Abdominocentesis was performed within 10 days before foaling and again 12 hours, 3 days, and 7 days after each horse foaled. Data recorded for each sample included total nucleated cell count, differential cell count, specific gravity, fibrinogen concentration, and total protein concentration. Smears of each sample were examined by a single clinical pathologist. Results: There were not any significant difference...
Horohov DW, Keadle TL, Pourciau SS, Littlefield-Chabaud MA, Kamerling SG, Keowen ML, French DD, Melrose PA.Intense exercise affects various parameters of the immune system. The overall effect of exercise on immune function is dependent upon the physical condition of the subject, the intensity and duration of the exercise period, and the immune parameter assessed. Unconditioned horses subjected to a single bout of intensive exercise exhibit multiple alterations in immune function, including an augmentation of lymphokine activated killer (LAK) cell function. This increase in LAK cell activity is not due to an increase in circulating LAK precursors. While peripheral blood mononuclear cells from exerci...
Simones P, De Geest JP, Lauwers H.The pectinate ligaments of ten horses, two donkeys, five oxen, five sheep, ten goats, five dogs, five cats, thirty pigs and two rabbits were studied under the stereomicroscope and the scanning electron microscope. In the horse and the donkey, the pectinate ligament was very prominent and was characterized by sturdy interconnected strands and relatively small intertrabecular spaces. The pectinate ligaments of ruminants were composed of shorter strands, separated by relatively larger spaces. Fusion between adjacent strands, resulting in the formation of fenestrated sheets, was regularly observed...
Rivero JL, Talmadge RJ, Edgerton VR.The aim of this study was to characterize the myosin heavy chain (MyHC) isoforms present in equine skeletal muscle. Methods: Muscle biopsies were removed from the superficial region of the gluteus medius muscle of five mature horses and analyzed by immunohistochemistry (using a battery of monoclonal antibodies specific for rat MyHC isoforms) and sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Results: Immunohistochemistry allowed subdivision of three different muscle fiber populations containing a single MyHC, one slow and two fast, and two hybrid populations, one containing slow an...
Wilson SM, Rakhit S, Murdoch R, Pediani JD, Elder HY, Baines DL, Ko WH, Wong PY.Experiments were undertaken using cultured equine sweat gland epithelial cells that express purine receptors belonging to the P2U subclass which allow the selective agonist uridine triphosphate (UTP) to increase the concentration of intracellular free Ca2+ ([Ca2+]i). Experiments using pertussis toxin (Ptx), which inactivates certain guanine-nucleotide-binding proteins (G-proteins), showed that this response consisted of Ptx-sensitive and Ptx-resistant components, and immunochemical analyses of the G-protein alpha subunits present in the cells showed that both Ptx-sensitive (alpha i1-3) and Ptx...
Adler CP, Friedburg H, Herget GW, Neuburger M, Schwalb H.DNA content, ploidy level, cell size and nuclear number were investigated in 54 mammalian hearts from nine species. DNA content was determined biochemically and ploidy level of cells was studied by the means of Feulgen cytophotometry. Nuclear number was calculated by a new method, while cell size was determined by using ocular micrometry. In most mammals diploid cell nuclei predominate. Higher ploidy levels were found in the human and the pig hearts. The total amount of DNA correlated with the myocardial weight. Eight million heart muscle cell nuclei were found in mice (myocardial weight 160 m...
Aurich JE, Kühne A, Hoppe H, Aurich C.Effects of seminal plasma on post-thaw motility and membrane integrity of cryopreserved horse spermatozoa were investigated. Carboxyfluorescein diacetate staining was used for the assessment of sperm membrane integrity. Adding 30% of seminal plasma from stallions with high post-thaw sperm motility to ejaculates from stallions with low post-thaw sperm motility increased progressive motility from 24.0 +/- 1.6 to 34.5 +/- 1.9% (P < 0.05) and membrane integrity from 27.0 +/- 2.1 to 34.3 +/- 2.3% membrane-intact spermatozoa (P < 0.05). Conversely, the addition of seminal plasma from stallions...
Wilson DA, Adelstein EH, Keegan KG, Barrett BA, Kutz RR.To determine whether monokines produced by activated rabbit peritoneal macrophages can inhibit development of exuberant granulation tissue formation in distal limb wounds in ponies. Methods: Randomized block. Methods: 5 castrated male ponies, 2 to 6 years old and weighing 140 to 190 kg. Methods: In vitro activity of cell-free rabbit peritoneal macrophage supernatant was determined after incubation of fibroblasts from the flank and the distal portion of limbs of horses and ponies. Tritiated thymidine was then added, and after reincubation, radioactivity was measured. After creation of a 4-cm2, ...
Watson ED, Bae SE, Thomassen R, Thomson SR, Woad K, Armstrong DG.The period between seasonal anoestrus and cyclicity is characterized in many mares by cyclical growth and regression of large dominant follicles. The insulin-like growth factor (IGF) system plays a key role in follicular growth and regression; therefore, we hypothesized that changes in the IGF system and its binding proteins would modulate onset of cyclicity in mares. Ovaries were obtained from pony mares on the day after detection of an actively growing 30 mm transitional anovulatory follicle, and also at the second or third oestrus of the breeding season on the day after the preovulatory fol...
Ferrante M, Andreeta A, Landoni MF.Diclofenac is a hydrophilic non-steroidal anti-inflammatory drug widely used in humans and animals. Previous reports have shown that this compound has low percutaneous absorption in horses. The effect of five penetration enhancers (10% urea, 15% and 20% oleic acid and 5% and 10% d-limonene) on the percutaneous absorption of diclofenac diethylamine through horse skin was evaluated in vitro using Franz-type diffusion cells. All tested penetration enhancers induced a significant increase in diclofenac diethylamine permeation, with limonene showing the highest enhancing effect at the lowest concen...
Miteva MA, Kossekova GP, Villoutreix BO, Atanasov BP.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...
Hejmej A, Wiszniewska B, Kosiniak-Kamysz K, Sadowska J, Bilińska B.Distribution of androgen receptors (ARs) in the epididymal duct and prostate of three entire stallions and one bilaterally cryptorchid horse was studied immunohistochemically using a polyclonal rabbit antiserum against the ARs. In both the healthy stallions and the cryptorchid, the epithelial cells of the epididymides showed nuclear staining for ARs. The intensity of AR-staining in the principal cells of the epididymis was stronger than that of the basal cells. In the prostate, the glandular secretory cells were moderately stained whereas the basal cells expressed weak AR-staining. Immunostain...
Tunón A-M , Katila T, Magnusson U, Nummijärvi A, Rodriguez-Martinez H.The T-cell response after the introduction of semen into the uterine cavity in the mare was studied by examining, immunohistochemically, the distribution of helper T-cells (CD4+) and cytotoxic T-cells (CD8+) in endometrial biopsy specimens. Endometrial tissue samples were obtained from twenty-five gynecologically healthy mares during estrus before and 6 or 48 h after deposition of a single dose of stallion semen. An increase (P=0.04) in the number of helper T-cells (CD4+) compared to pre-insemination values was observed in the uterine body in both groups, 6 and 48 h, after insemination. No sig...
Gallardo Bolaños JM, Balao da Silva C, Martín Muñoz P, Plaza Dávila M, Ezquerra J, Aparicio IM, Tapia JA, Ortega Ferrusola C, Peña FJ.To investigate the mechanisms inducing sperm death after ejaculation, stallion ejaculates were incubated in BWW media during 6 h at 37°C. At the beginning of the incubation period and after 1, 2, 4 and 6 h sperm motility and kinematics (CASA), mitochondrial membrane potential and membrane permeability and integrity were evaluated (flow cytometry). Also, at the same time intervals, active caspase 3, hydrogen peroxide, superoxide anion (flow cytometry) and Akt phosphorylation (flow cytometry) were evaluated. Major decreases in sperm function occurred after 6 h of incubation, although after 1 h ...
Ousey JC, Prandi S, Zimmer J, Holdstock N, Rossdale PD.To determine the effect of diet on energy intake, loss, and metabolism in foals 2 to 7 days old. Methods: 14 pony foals. Methods: Group-A foals suckled their dams, group-B foals were fed milk replacer, and group-C foals were fed by total parenteral nutrition (TPN). Energy balance studies were performed over 8-hour periods on postpartum days 2, 4, and 7. Results: Mean gross energy (GE) intake of group-A foals increased between days 2 and 7. Approximately 3% of GE was excreted in urine and feces, and energy expenditure remained constant. These foals were in positive energy balance, and mean body...
Kraemer DC.The procedures that are collectively referred to as embryo transfer (ET) have many uses. They were first used as research tools to study fetal-maternal physiology. Since the first successful mammalian embryo transfer in 1890, ET has been utilized for enhancement of genetic selection; diagnosis and treatment of infertility; control of infectious disease transmission; screening for genetic defects; propagation of rare and endangered species; and the study of developmental biology. Most of the embryo transfers have been intraspecific. A listing of the species includes rabbit, rat, sheep, mouse, g...
Herrera C, Morikawa MI, Castex CB, Pinto MR, Ortega N, Fanti T, Garaguso R, Franco MJ, Castañares M, Castañeira C, Losinno L, Miragaya MH, Mutto AA.Normal mammalian early embryonic development involves apoptosis of blastomeres as a remodeling process during differentiation, starting at the blastocyst stage. Genomic DNA has been recently detected in the blastocele fluid of human embryos and has been amplified by real-time polymerase chain reaction (PCR) to diagnose the sex of in vitro-produced human embryos. This new approach varies from conventional preimplantation genetic diagnosis in that no cells are extracted from the embryo and only the blastocele fluid is aspirated and used as a DNA sample for diagnosis. In the present work, we inv...
Clegg PD, Jones MD, Carter SD.Loss of articular cartilage, which is the most important pathological lesion occurring in osteoarthritis, has been shown to be enzymatically mediated. The matrix metalloproteinases (MMPs) are a group of enzymes which have been implicated in this degradation of articular cartilage matrix. The use of pharmacological agents to inhibit this catabolic process in the joint is a potential route for therapeutic intervention. The gelatinase MMPs, MMPs-2 and 9, were purified by affinity chromatography from equine cell cultures. The ability of phenylbutazone, flunixin, betamethasone, dexamethasone, methy...
Iglesias BF, Catalá A.The aim of the present study was to analyze the time-course of t-butyl hydroperoxide-induced changes in lipid peroxidation, fatty acid composition and chemiluminescence intensity in rat, caprine, equine and bovine erythrocyte ghosts. A relatively high content of arachidonic acid (C20:4 n6) and docosahexaenoic acid (C22:6 n3) was characteristic of the rat erythrocyte ghosts. The fatty acid composition of native erythrocyte ghosts obtained from caprine, equine and bovine was characterized by a high content of oleic acid (C18:1 n9) and a low content of the peroxidable polyunsaturated fatty acids ...
Hernández-Avilés C, Love CC, Serafini R, Teague SR, Varner DD.Commonly marketed semen extenders contain various antibiotic types and concentrations to control bacterial growth from stallion's external genitalia. An experiment was conducted to test the effects of supplemental amikacin disulfate (1,000 μg/mL) + potassium penicillin G (1,000 IU/ML: INRA-AP), or ticarcillin-clavulanate (1,000 μg/mL: INRA-TIM) in the INRA 96 extender, on sperm function and antimicrobial activity, compared with extender without supplemental antibiotics (INRA-C). In freshly extended semen (Time 30m), no differences were observed among the three treatment groups for sperm m...
Peters GJ, De Abreu RA, Oosterhof A, Veerkamp JH.Concentrations of purine and pyrimidine ribonucleotides were measured with HPLC in lymphocytes of man, horse, pig and sheep and in rat thymocytes. The ATP concentration was highest in lymphocytes of all species and about 850 pmol/10(6) cells in human and equine lymphocytes, higher in porcine and lower in ovine lymphocytes and rat thymocytes. The GTP concentration was comparable in human, equine and porcine lymphocytes, but lower in ovine lymphocytes. ATP concentration was also measured in lymphocytes of man, horse and pig with a luciferin-luciferase assay. During culturing with or without phyt...
Lombardo D, Chapus C, Bourne Y, Cambillau C.Horse (Equus caballus) pancreatic lipase (EC 3.1.1.3) has been crystallized using the hanging drop method of vapour diffusion at 20 degrees C. The best crystals were grown from an 8 mg/ml solution in 10 to 20% (w/v) polyethylene glycol 8000, 10 mM-MgCl2, 0.1 M-NaCl, 0.1 M-Mes buffer (pH 5.6). They reach dimensions of 0.8 mm x 0.4 mm x 0.6 mm. X-ray examination of the lipase crystals shows that they are orthorombic with a space group P2(1)2(1)2(1). Their cell dimensions are a = 79.8 A, b = 97.2 A c = 145.3 A. Two molecules per asymmetric unit give a Vm value of 2.82 A3/dalton (56% water content...
Mills PC, Cross SE.Commercial formulations of non-steroidal anti-inflammatory drugs (NSAIDs) are developed for human use but the extent to which they will pass through equine skin is unknown. Skin was harvested from five Thoroughbred geldings from the thorax, groin and leg (dorsal metacarpal) regions and frozen (-20 degrees C) until required. Two grams of methylsalicylate (MeSa) gel was applied to defrosted full-thickness samples in diffusion cells and the penetration of MeSa and its active metabolite, salicylate (Sa), through skin samples were measured over 24 h. Significantly higher (P < or = 0.02) total sa...
Castro T, Jacob JC, Domingues RR, Ginther OJ.Prostaglandin E2 (PGE2) and prostaglandin F2α (PGF2α) are involved in equine embryo mobility throughout the uterus on Days 11-15 (ovulation = Day 0). On a day (Day 12) of maximal embryo mobility in pregnant mares (n = 13) and before luteolysis in nonbred mares (n = 10), gene expressions were compared between the uterine horns that did and did not contain the mobile embryo and between pregnant and nonbred mares. A cytobrush was used to collect an endometrial sample from the middle of each uterine horn. In nonbred mares, there was no difference for any of the considered gene expressions ...
Johannisson A, Gröndahl G, Demmers S, Jensen-Waern M.Methodological aspects of flow-cytometric evaluation of the phagocytic properties of equine neutrophils were elucidated. The kinetics of attachment and ingestion were studied, and the phagocytic process was more rapidly completed when serum-opsonized yeast cells were used than with use of IgG-opsonized yeast cells. Trypan blue was successfully used to quench fluorescence of non-ingested yeast cells. There were only minor differences in the kinetics of phagocytosis between quenched and unquenched samples, indicating that attachment is rapidly followed by ingestion. Trypan blue quenching caused ...
Brown KA, Boerboom D, Bouchard N, Doré M, Lussier JG, Sirois J.17Beta-hydroxysteroid dehydrogenase type 4 (17betaHSD4) has a unique multidomain structure, with one domain involved in 17beta-estradiol inactivation. The objective of the study was to investigate the regulation of 17betaHSD4 during human chorionic gonadotropin (hCG)-induced ovulation/luteinization. The equine 17betaHSD4 cDNA was cloned and was shown to encode a 735-amino acid protein that is highly conserved (81-87% identity) compared with other mammalian orthologs. RT-PCR/Southern blot analyses were performed to study the regulation of 17betaHSD4 transcripts in equine preovulatory follicles ...
Bachmann M, Czetö A, Romanowski K, Vernunft A, Wensch-Dorendorf M, Wolf P, Metges CC, Zeyner A.Postprandial alterations of plasma amino acid (PAA) levels partly reflect a temporal contribution of the feed. How cereal grains affect PAA levels is not known. We hypothesized that a meal of cereal grains causes a temporal increase of PAA, affected by grain species, grain genotype and meal size. Six mares were used in three consecutive trials, receiving four oats, barley and maize genotypes, respectively. Individual grain genotypes were provided as 3 meal sizes corresponding to 1.0, 1.5 or 2.0 g starch/kg body weight. Meadow hay (1.5 kg/100 kg body weight) was offered daily. At the test...
Cerón JJ, Tecles F, Espín JC.Effects of seven different blood diluents (distilled water, Triton X-100, saponin, isotonic saline solution, pH 7.5 and 8 phosphate buffers and bovine serum albumin) and two chromophores: 5, 5'-dithiobis 2-nitrobenzoic acid (DTNB) and 2,2'-dithiodipyridine (2- PDS) on blood cholinesterase determination in four domestic species (cow, sheep, goat and horse) are described and compared. Haemolytic diluents (distilled water, Triton X-100 and saponin) gave the best precision results when fresh blood was assayed. However, Triton X-100 induced lower ChE activity values in horses, and saponin yielded v...
Patton ME, Andrews FM, Bogers SH, Wong D, McKenzie HC, Werre SR, Byron CR.Ileus is a common life-threatening problem in horses, and currently available treatments may be ineffective. The purpose of this study was to determine whether bit chewing, a form of sham feeding, decreases the gastric emptying time (GET), small intestinal transit time (SITT), and total orocecal transit time (OCTT) in clinically normal horses in a prospective crossover study. Nine healthy horses were acclimated and fed a standardized diet. Following 24 h of fasting, self-contained video endoscopy capsules and acetaminophen were administered into the stomach via a nasogastric tube. Each horse u...
Jones I, Madej A.Microtitre plates were coated with antiserum against oestradiol-17 beta-6-(O-carboxymethyl)-oxime bovine serum albumin raised in sheep. The plasma samples (0.2-1.0 ml) were extracted with peroxide-free diethyl ether prepared daily by treatment with Al2O3. The enzyme conjugate was prepared by coupling oestradiol-17 beta-6-(O-carboxymethyl)-oxime to horse-radish peroxidase. The conjugate was chromatographed on a Sephadex G-25 column. The standard curve ranged from 0.37 to 18.40 fmol/well of oestradiol-17 beta. The amount of oestradiol-17 beta causing a 50% reduction of maximum binding was 4.4 fm...
Muir WW, Sams RA, Hubbell JA, Hinchcliff KW, Gadawski J.To determine the effects of IV administration of enalaprilat on cardiorespiratory and hematologic variables as well as inhibition of angiotensin converting enzyme (ACE) activity in exercising horses. Methods: 6 adult horses. Methods: Horses were trained by running on a treadmill for 5 weeks. Training was continued throughout the study period, and each horse also ran 2 simulated races at 120% of maximum oxygen consumption. Three horses were randomly selected to receive treatment 1 (saline [0.9% NaCl] solution), and the remaining 3 horses received treatment 2 (enalaprilat; 0.5 mg/kg of body weig...
McBride SD, Roberts K, Hemmings AJ, Ninomiya S, Parker MO.Stress and genotype elicit changes in impulse control in a range of species that are attributable to adaptations in both the central and peripheral nervous system. We examined aspects of this mechanism in the horse by assessing the effect of a dopamine receptor genotype (DRD4) and central dopaminergic tone (measured via spontaneous blink rate [SBR] and behavioral initiation rate [BIR]), on measures of impulsivity, compulsivity (3-choice serial reaction time task) and sympathetic/ parasympathetic system balance (heart rate variability [HRV]). Genotype did not have a significant effect on any of...
Coleman MC, Walzem RL, Kieffer AJ, Minamoto T, Suchodolski J, Cohen ND.Lipoproteins are water-miscible macromolecules enabling the transport of lipids in blood. In humans, altered proportions of lipoproteins are used to detect and classify metabolic diseases. Obesity and obesity-related comorbidities are common in horses. The pathophysiology of obesity is poorly understood and likely multifactorial. Development of new diagnostic tests to identify horses at risk of developing obesity to implement preventative measures is critical; however, a necessary first step to accomplish this goal is to improve our understanding of the pathophysiology of disease. Thus, the ob...
Ababneh M, Ababneh H, Shidaifat F.Phospholipase A2 (PLA2) is a key enzyme for biosynthesis of PGF2α. Real-time RT-PCR and immunohistochemistry were used to determine transcription and cellular distribution of cytosolic PLA2 (cPLA2) in the equine endometrium during the oestrous cycle and early pregnancy. Endometrial biopsy and blood samples were collected from cycling mares on days (d) 8, 11, 15 and 18 (oestrus) (Day 0 = Day of ovulation; n = 5 for each day) and from pregnant mares (n = 4) on d15. Except for mares on d18 and some cyclic mares (n = 2) on d15 with low progesterone (P₄) concentrations (< 3.18 nm), P₄ conce...
Hernández-Vidal G, Jeffcott LB, Davies ME.A polyclonal antiserum raised in sheep against human cathepsin B was tested for specificity and cross-reactivity with the horse homologue by SDS-PAGE and Western blotting, prior to being used for immunolocalization of the enzyme in equine articular cartilage. In Western blots, the antiserum recognized the 30 kDa single chain and 25 kDa heavy chain of the mature enzyme in purified bovine cathepsin B, and corresponding bands at 32 and 27 kDa in equine chondrocyte and fibroblast lysates. This antiserum was then used to compare the expression and distribution of cathepsin B in normal and dyschondr...
Farrar RG, Klei TR.Strongylus edentatus was successfully cultured in vitro to the fourth larval stage (L4). Some growth continued for periods of 40-50 days at which time reductions in viability were observed in some of the culture systems tested. Various combinations of media, sera, buffers and organ explant cultures were tested. All cultures were incubated at 37 C in an atmosphere of 95% air and 5% CO2. Larvae underwent growth and differentiation to the L4 in all medium-serum combinations with and without organ explant cultures. Development and growth did occur but viability was reduced to insignificant levels ...
Schaller J, Rickli EE.The N-terminal amino acid sequence of equine, ovine, canine, goat and rabbit plasminogen were determined and compared with those already known of the human, bovine, porcine and feline molecule. Furthermore, the kringle 4 domains of equine, ovine, canine and goat plasminogen, prepared by limited cleavage with elastase, were sequenced and compared with the known species of human, bovine, porcine and chicken plasminogen. Homology with the human kringle 4 ranges between 73% (chicken) and 90% (bovine). Comparison of sequences, fragmentation patterns with elastase and adsorption on lysine-Bio-Gel su...
