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Topic:Erythrocytes
Erythrocytes, or red blood cells, are the most abundant cell type in the equine circulatory system and are responsible for transporting oxygen from the lungs to tissues throughout the body. They also facilitate the return of carbon dioxide from tissues to the lungs for exhalation. Equine erythrocytes are characterized by their biconcave disc shape, which enhances their flexibility and surface area for gas exchange. The lifespan of erythrocytes in horses is approximately 140-150 days, after which they are removed from circulation and broken down, primarily in the spleen. Variations in erythrocyte count, size, and morphology can indicate various health conditions, including anemia, dehydration, and certain metabolic disorders. This page compiles peer-reviewed research studies and scholarly articles that explore the structure, function, and clinical implications of erythrocytes in equine health.
Hepatoblastoma with erythrocytosis in a young female horse. A 2.5-year-old female Thoroughbred was examined because of lethargy, anorexia, and weight loss. Analysis of a CBC revealed erythrocytosis and an increase in PCV. Serum biochemical analysis revealed increases in activities of several hepatic enzymes. Ultrasonography revealed hepatomegaly and a heterogeneous appearance of the hepatic parenchyma. The horse did not improve despite supportive care, and it was euthanatized. Necropsy revealed numerous raised white to gray foci in the liver. Histologically, these foci consisted of neoplastic cells that resembled fetal hepatocytes, embryonal-type cells...
Ventilation-perfusion relationships during exercise in standardbred trotters with red cell hypervolaemia. In order to evaluate the pulmonary gas exchange during exercise in Standardbred trotters with red cell hypervolaemia (RCHV), 12 horses with RCHV were compared with 9 normovolaemic (NV) horses. VO2 and VCO2 were determined with an open bias flow system. Cardiovascular and haemodynamic data were recorded during exercise at 4 different speeds on a treadmill. Pulmonary gas exchange was assessed by conventional blood gas variables (arterial and mixed venous blood gas tensions), and the ventilation-perfusion distribution VA/Q was estimated by the multiple inert gas elimination technique. VA and AaDO...
Factors affecting accumulation of lactate in red blood cells. In horses, both the post exercise distribution of lactate between plasma and red blood cells (RBC) and the activity of lactate transporters on the RBC membrane vary widely between individuals. In this study, we investigated the effects of pH, time and temperature on lactate distribution in vitro, and compared the in vitro activity of lactate transporters with the accumulation of lactate into RBC in vivo. To accomplish this, we took venous blood samples at rest and after trotting races. The post exercise accumulation of lactate into RBC was shown to depend on the activity of lactate transporter...
Functional and compositional changes in pulmonary surfactant in response to exercise. Pulmonary surfactant from bronchoalveolar lavages was obtained from 2 groups of horses. A control group consisting of 6 healthy racehorses that were paddock-rested and lavaged weekly for 6 consecutive weeks were compared with an experimental group of 10 healthy racehorses, lavaged weekly the same period, consisting of a 5 week incremental-intensity treadmill training programme and one week post training paddock rest. Phospholipid content of lavage fluid was determined indirectly by phosphorus assay, and surfactant functional activity was determined by bubble surfactometry. Total cell counts an...
Fragility of red cells during exercise is affected by blood pH and temperature. We examined the relationship in horses between osmotic fragility of erythrocytes (OFE) measured as the red cell haemolysis rates (HLR) in 0.56% NaCl and certain physiological characters. Animals were exercised on a treadmill: warmed up at 30% VO2max for 5 min or at 105% VO2max for 1 min, given an exercise test at 80 or 105% VO2max until fatigued, and then cooled down. The pH and temperature of the blood had a significant correlation for the HLR: r = 0.93 and 0.92 (P < 0.01) on arterial and mixed venous blood, respectively. In multiple regression analysis, heart rate and packed cell volume s...
Sequential changes in bronchoalveolar cytology after autologous blood inoculation. Six horses, free of recent exercise-induced pulmonary haemorrhage (EIPH), each had 8 bronchial segments inoculated with 40 ml of autologous blood lavaged on Days 3, 5, 7, 10, 14 and 21 after inoculation. The bronchoalveolar lavage (BAL) fluid samples were analysed, and total leucocyte counts and differential cell percentages determined. Statistical analysis of the differences between the 8 post inoculation and 1 pre-inoculation (control) lavage sites demonstrated an early neutrophilic response, rising from < 5% of alveolar leucocytes to 10% by 24-48 h post inoculation. As this response wane...
Bone marrow response to large volume blood collection in the horse. Evaluation of erythropoietic regeneration in horses is difficult unless serial bone marrow aspirates are performed. To investigate the acute and chronic erythropoietic regenerative response of equine bone marrow following acute removal or loss of blood, sequential bone marrow aspirates over 4 weeks were taken from the sternum of five horses from which 20 ml kg(-1)of blood had been removed. We found that the total number of erythroid cells counted (expressed as a percentage of the total number of erythroid and myeloid cells counted) expanded initially by 13.7 per cent within 3 days after blood ...
Erythrocyte associated haemato-biochemical changes in Babesia equi infection experimentally produced in donkeys. Equine babesiosis, caused by Babesia equi and transmitted by ticks is of major economic importance in India. The adverse effects which B. equi organism and its metabolites inflict on red blood cells have not been reported. Erythrocytes were analysed for red cell membrane phospholipids, proteins and haemoglobin (Hb) concentration and plasma for malondialdehyde (MDA) in B. equi carrier donkeys before splenectomy (50% parasitaemia. Before splenectomy the mean values of membrane protein, phospholipids, plasma MDA and Hb were found to be 1.63 +/- 0.12 mg/ml PCV, 2.28 +/- 0.9 mg/ml PCV, 3.63 +/- 0.3...
Molecular detection of Babesia equi and Babesia caballi in horse blood by PCR amplification of part of the 16S rRNA gene. Babesia equi and Babesia caballi are tick-borne haemoparasites that may cause babesiosis of Equidae. In southern Europe B. equi is enzootic and infections may occur asymptomatically and more frequently than those due to B. caballi. Complement fixation test (CFT) is the official serological test for the diagnosis of equine babesiosis, but it has low sensitivity during early and latent stages of the disease. With the aim of developing more sensitive and rapid direct diagnostic alternatives, PCR systems that amplified DNA targets of 664 or 659 bp regions of the 16S rRNA genes were designed and de...
The erythrocyte cytoskeleton protein 4.2 is not demonstrable in several mammalian species. Erythrocyte membrane proteins from 44 representative mammals were studied. Protein 4.2 was not detected in guinea pigs (Cavia porcellus) (N = 14), Southern Brazilian swamp large rats (Myocastor coypus) (N = 2), cutias (Dasyprocta sp) (N = 4), and horses (Equus caballus) (N = 13). These animals also presented high ankyrin concentrations except for the horse which did not exhibit a sharp band, although minor components located between proteins 2 and 3 could account for the ankyrin family. The rodents studied did present band 6, which was not detectable in other common rodents such as white rats ...
[The effect of the essential fatty acids in mare’s milk on the function of the immune system and of nonspecific resistance in rats]. The influence of essential fatty acids of mare's milk fat on the immunocompetent system and nonspecific resistance of male rats weighing 135-145 g was investigated after 6 weeks of feeding. Rats were fed with isocaloric purified diets containing 15% of test fat (in control--combination of lard and sunflower oil) which provide the ratio of omega-6/omega-3 fatty acids equal to 0.76. An increase of immune responsiveness and nonspecific resistance in the group fed with the diet with mare's milk fat on day 6 after a single immunization of the animals with 5% sheep erythrocyte suspension was noted.
Comparison of microbiologic and high-performance liquid chromatography assays to determine plasma concentrations, pharmacokinetics, and bioavailability of erythromycin base in plasma of foals after intravenous or intragastric administration. To determine pharmacokinetics and bioavailability of erythromycin base after intragastric administration and erythromycin lactobionate after IV administration to healthy foals and to compare a microbiologic assay with a high-performance liquid chromatography (HPLC) method to determine plasma concentrations of erythromycin A. Methods: 6 healthy foals that were 2 to 4 months old. Methods: Foals were given single doses of erythromycin (10 mg/kg of body weight, IV, and 25 mg/kg, intragastrically) in a crossover study. Venous blood samples were obtained at specific times after drug administration, ...
Reduction of CD4+ and CD8+ T lymphocytes during febrile periods in horses experimentally infected with equine infectious anemia virus. Three horses were experimentally infected with equine infectious anemia virus (EIAV). All horses were febrile after inoculation with EIAV and then developed chronic symptoms with intermittent fever. The febrile period was characterized by a rise in body temperature with reduced PBL and erythrocyte counts. Flow cytometric analysis showed that the reduced number of lymphocytes was due to significant decreases in CD4+ and CD8+ T cells in the absence of any change in B cell number. At the end of the febrile period the body temperature began to recover and numbers of CD4+ and CD8+ T cells showed a ...
Oxygen-dependent K+ influxes in Mg2+-clamped equine red blood cells. 1. Cl--dependent K+ (86Rb+) influxes were measured in oxygenated and deoxygenated equine red blood cells, whose free [Mg2+]i had been clamped, to examine the effect on O2 dependency of the K+-Cl- cotransporter. 2. Total [Mg2+]i was 2.55 +/- 0.07 mM (mean +/- s.e.m. , n = 6). Free [Mg2+]i was estimated at 0.45 +/- 0.04 and 0.68 +/- 0. 03 mM (mean +/- s.e.m., n = 4) in oxygenated and deoxygenated red cells, respectively. 3. K+-Cl- cotransport was minimal in deoxygenated cells but substantial in oxygenated ones. Cl--dependent K+ influx, inhibited by calyculin A, consistent with mediation via the ...
Cardiovascular and metabolic adaptations in horses competing in cross-country events. The cardiovascular and metabolic response to two cross-country events (CC*: preliminary level and CC*** advanced level) were analysed in 8 male eventing horses (4 Anglo-Hunter and 4 Anglo-Arabian). This study focused on the establishment of the main metabolic pathways involved in the muscle energy resynthesis during the competitions. Heart rate (HR) was recorded throughout the CC events. Jugular venous blood samples were withdrawn before the warm-up period, immediately after the competitions and at 5 and 10 min in the recuperation period. The following haematological parameters were studied: r...
Tubular structures associated with Babesia caballi in equine erythrocytes in vitro. In-vitro-propagated Babesia caballi parasites were examined by scanning and transmission electron microscopy. Many small pores were observed over the entire surface of infected erythrocytes on scanning electron microscopy, and on transmission electron microscopy these small pores were found to be openings of tubular structures. By the examination of a number of infected cells the tubular structures were found to be connected with the parasite, and this observation might indicate that the tubular structures arose the edge of the parasite and terminated at an Invagination on the surface of the e...
Hematologic and serum biochemical variables and plasma corticotropin concentration in healthy aged horses. To compare hematologic and serum biochemical variables and plasma ACTH concentration between healthy horses 5 to 12 years old and those more than 20 years old. Methods: 30 healthy horses 5 to 12 years old and 30 healthy horses more than 20 years old. Methods: Venous blood was collected from all horses, and CBC and serum biochemical analysis were performed for each horse. Plasma ACTH concentration was determined by radioimmunoassay. Student's paired t-test or the Mann-Whitney rank sum test was used to compare values between control and aged horse groups. Results: Compared with values for contro...
Babesia equi field isolates cultured from horse blood using a microcentrifuge method. Babesia equi, a causative agent of equine piroplasmosis, was isolated from horses in the Chaco Province of Argentina, a known piroplasmosis endemic region. Fifteen B. equi field isolates were acquired by culture from 23 actively working horses from 2 ranches. The horses appeared healthy with no clinical signs or histories indicative of equine piroplasmosis. All 23 horses had B. equi-specific antibody activity by the indirect fluorescent antibody test and 18 were also complement fixation test positive for B. equi. Equine erythrocytes were prepared for parasite culture using a microcentrifuge tu...
Quantification of exercise-induced pulmonary haemorrhage with bronchoalveolar lavage. Exercise-induced pulmonary haemorrhage (EIPH) causes serious economic losses in the horse racing industry. Endoscopic examination indicates that 40-90% of horses exhibit EIPH following sprint exercise, but the limitations of the endoscope prevent diagnosis in many horses. Bronchoalveolar lavage (BAL) was utilised to detect red blood cells (RBCs) in the terminal airways in 6 horses. Two lavages were performed at weekly intervals prior to exercise, one within 90 min after exercise, and 5 at weekly intervals after exercise. The horses were exercised strenuously at 12.5-14.6 m/s on a treadmill (3 ...
Increase in blood viscosity in the sprinting horse: can it account for the high pulmonary arterial pressure? Blood was taken from 49 Thoroughbred horses before and after racing at the track to determine if frusemide modified the apparent viscosity of the blood and to determine the effects of changes in shear rate and packed cell volume (PCV), associated with strenuous exercise, on apparent and relative viscosities. Small increases in apparent viscosity of the blood (at a specified PCV and shear rate) occurred in horses given frusemide compared to those receiving no frusemide; however, no differences were seen in relative viscosity. Although 2 groups of horses, those receiving frusemide before racing ...
Effects of a sudden flow reduction on red blood cell rouleau formation and orientation using RF backscattered power. In most studies that were aimed at evaluating the kinetics of red blood cell (RBC) aggregation, human blood was initially circulated at a high shear rate to disrupt the aggregates, and measurements were performed following a complete flow stoppage, during the process of rouleau formation. However, it is known that a very low shear rate can enhance the formation of aggregates, as demonstrated by the modal relationship of the shear-rate dependence of RBC aggregation. The objective of the present study was, thus, to evaluate the influence of sudden flow reductions compared to a complete flow stop...
Monoclonal antibody against Babesia equi: characterization and potential application of antigen for serodiagnosis. Monoclonal antibody (MAb) BEG3 was produced against Babesia equi parasites to define a species-specific antigen for diagnostic use. The MAb reacted with single, paired, and Maltese cross forms of B. equi, and no reaction was observed with this MAb on acetone-fixed Babesia caballi, Babesia ovata, or Babesia microti parasites in the indirect immunofluorescent antibody test. Confocal laser and immunoelectron microscopic studies showed that the antigen which was recognized by this MAb was located on the surface of B. equi parasites. This MAb recognized a 19-kDa protein of B. equi antigen and did n...
Evaluation of a haematological analyser (Sysmex F-800) with equine blood. A semiautomatic electronic blood cell counter (Sysmex F-800) was evaluated with equine blood, according to the protocol of the International Committee for Standardization in Haematology (ICSH, 1984). The precision and overall reproducibility were acceptable for all the parameters studied except for the platelet count, in which a coefficient of variation of 18.8% and 21.7% was obtained for within and between batch precision and 26.76% for overall reproducibility. Carry-over for the haematocrit value and platelet count was unsatisfactory, thus the use of a blank diluent sample between different ...
Interindividual variation in total and carrier-mediated lactate influx into red blood cells. To study in standardbred horses interindividual variation in the influx of lactate into red blood cells, venous blood samples were collected from 89 horses from 2 wk to 9 yr of age. For 62 horses, the rate of influx was normally distributed with a mean rate of 4.09 nmol.mg protein-1.min-1 at a lactate concentration of 10 mM, and the respective value for the other 27 horses was 0.58 nmol.mg protein-1.min-1. At 30 mM of lactate, the rates were 8.71 and 1.97 nmol.mg protein-1.min-1, respectively. This bimodal distribution was independent of age. In horses with high transport activity, the monocar...
Adenosine and hypoxanthine transport in horse erythrocytes: evidence for a polymorphism in the transport of hypoxanthine via a sodium-dependent cotransporter. The inward transport of two purines, adenosine and hypoxanthine, at 37 degrees C by horse erythrocytes was compared. No mediated transport of adenosine was detected in horse erythrocytes, nor was saturable, high-affinity binding of the potent facilitated-diffusion inhibitor nitrobenzylthioinosine demonstrable in horse erythrocyte membranes. In contrast, erythrocytes from most horses possessed a saturable sodium-dependent hypoxanthine transporter (apparent K(m), 100 +/- 28 microM; Vmax, 0.20 +/- 0.08 mmol (l cells)-1 h-1; means +/- S.E.M., n = 5). Guanine inhibited hypoxanthine influx (apparent...
Effect of exercise on erythrocyte beta-adrenergic receptors and plasma concentrations of catecholamines and thyroid hormones in Thoroughbred horses. The effects of exercise stress on erythrocyte beta-adrenergic receptor characteristics and plasma concentrations of adrenaline, noradrenaline and thyroid hormones were studied in Thoroughbred racehorses during rest and after exercise. Five minutes after a maximal speed race of 1200 +/- 200 m (mean +/- s.d.), both plasma adrenaline and noradrenaline concentrations increased with respect to basal values (from 2.48 +/- 0.15 to 3.83 +/- 0.27 and from 2.13 +/- 0.11 to 3.53 +/- 0.27 nmol/l respectively). The increment of adrenaline was greater in high performance (HP) as compared to low performance ...
Erythroid hypoplasia and anemia following administration of recombinant human erythropoietin to two horses. A Standardbred gelding and a colt were examined because of poor performance and anemia. Each horse had been given recombinant human erythropoietin (rhEPO; 4,000 IU) at least twice within the preceding 2 to 4 months. The horses had an Het of 16 and 24%, serum iron concentrations of 210 and 304 micrograms/dl (reference range, 73 to 140 micrograms/dl), total iron binding capacities of 239 and 321 micrograms/dl (reference range, 266 to 364 micrograms/dl), values for the percentage saturation of transferrin by iron of 87.9 and 94% (reference range, 20 to 52%), and serum ferritin concentrations of 2...
