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Topic:Comparative Study
Comparative studies in equine research involve the systematic analysis of different horse breeds, management practices, or physiological responses to identify variations and similarities. These studies are instrumental in understanding how different factors influence health, performance, and behavior in horses. Common areas of comparison include genetic traits, nutritional requirements, disease resistance, and response to training. By evaluating these differences, researchers can develop targeted strategies for breeding, healthcare, and training. This page aggregates peer-reviewed research studies and scholarly articles that focus on the methodologies, findings, and implications of comparative studies in the context of equine science.
Heterogeneity of pericyte populations in equine skeletal muscle and dermal microvessels: a quantitative study. The objective of this ultrastructural investigation was to determine if populations of pericytes in equine dermal and skeletal muscle capillaries increase in a head-to-foot direction, as has been reported in human skeletal muscles. Samples of equine microvessels were obtained from the longissimus dorsi skeletal muscle 150 cm. from the ground, from the dermis above this muscle, from the extensor carpi radiali muscle at 55 cm. from the ground, from the dermis adjacent to that muscle, and from dermis 15 cm. from the ground, just above the hoof wall. Tissues were processed for transmission electro...
Differential distribution of immunoreactive S-100 protein in mammalian testis. The present study deals with the immunohistochemical localization of S-100 protein in the testes of seven mammalian species including rat, cat, dog, pig, sheep, cattle and horse. Significant differences are demonstrated in the cellular distribution and intensity of immunoreaction for the protein. In bull, ram, boar and cat testes S-100 protein was localized in the cytoplasm and nuclei of Sertoli cells. A particularly intense staining was seen in the modified Sertoli cells of the terminal tubular segment. With the exception of the cat and horse S-100 protein immunoreactivity was additionally fo...
Potency of partially purified malleo-proteins for mallein test in the diagnosis of glanders in equines. Malleo-proteins from synthetic broth mallein of six strains of Pseudomonas mallei were separated by trichloroacetic acid precipitation, ammonium sulfate precipitation and Ultrogel AcA 34 gel filtration chromatography. When tested comparatively with Dutch PPD mallein as standard on P. mallei-sensitized and normal horses all the strains were found to be malleinogenic, trichloroacetic acid precipitated proteins were comparable to Dutch PPD mallein in potency and innocuity whereas ammonium sulfate-precipitated proteins elicited non-specific reactions. Ultrogel AcA 34 chromatographed high molecular...
Abdominal radiography for diagnosis of enterolithiasis in horses: 141 cases (1990-1992). Medical records of 245 horses that had been evaluated by use of abdominal radiography between January 1990 and December 1992 were reviewed. One hundred forty-one horses subsequently had a postmortem examination or surgical exploration performed for definitive lesion diagnosis. The signalment, diagnosis, site, and number of enteroliths were obtained from the medical records. Radiographs were evaluated individually by 3 reviewers for the presence of enteroliths, preferred diagnostic view, evidence of large colon tympany, and film quality. Of the 141 cases reviewed, 66.7% (94/141) had confirmed e...
Evaluation of a monoclonal antibody-based colony blot test for rapid identification of virulent Rhodococcus equi. We recently generated a monoclonal antibody immunoglobulin G1 (MAb 10G5), which can recognize 15- to 17-kDa antigens, virulence-associated antigens of Rhodococcus equi, and developed a colony blot enzyme-linked immunosorbent assay with MAb 10G5 for the rapid identification of virulent R. equi. In this epidemiologic study, we evaluated the results of the colony blot test in the identification of virulent isolates of R. equi from feces of horses and soil and compared them with those from a conventional procedure (plasmid profiles of isolates by agarose gel electrophoresis). Environmental isolate...
Genetic analysis of equine rotavirus by RNA-RNA hybridization. Serotype G3 equine rotaviruses isolated in Japan made up a common genogroup and were classified into two different genotypes. The genomes of serotype G3 equine rotaviruses with an identical electropherotype (isolated from 1982 to 1989) were very closely related to each other regardless of the year in which they were isolated. Serotype G3 equine rotavirus BI originating from England belonged to the same genogroup of serotype G3 equine rotaviruses isolated in Japan, although BI was classified as having a different genotype. The genomes of both serotype G10 equine rotavirus R-22 and serotype G10 ...
The immunology of companion animals: reagents and therapeutic strategies with potential veterinary and human clinical applications. There is now a wide range of immunological reagents that can be used in the diagnosis and treatment of diseases in the companion animals (dogs, cats and horses). Many of these diseases are the veterinary equivalents of human conditions, and may therefore provide good models to study basic pathogenic mechanisms.
Molecular weight alterations of alpha-1 proteinase inhibitor in equine bronchoalveolar lavage fluid. The equine alpha-1 proteinase inhibitor (alpha 1PI) system differs from that of man in that the equine system consists of four closely-linked genes (Spi1-Spi4) whereas in man, a single gene encodes for alpha 1PI. We have previously found differences in the proportion of the Spi proteins in equine serum and bronchoalveolar lavage fluid (BALF). We therefore wished to determine whether, as reported in man, there was any molecular weight difference between the Spi proteins in serum and BALF. alpha 1PI and albumin from equine BALF migrated further towards the anode compared with serum alpha 1PI on ...
Polymorphic sequence in the D-loop region of equine mitochondrial DNA. The D-loop regions in equine mitochondrial DNA were cloned from three thoroughbred horses by polymerase chain reaction (PCR). The total number of bases in the D-loop region were 1114 bp, 1115 bp and 1146 bp. The equine D-loop region is A/T rich like many other mammalian D-loops. The large central conserved sequence block and small conserved sequence blocks 1, 2 and 3, that are common to other mammals, were observed. Between conserved sequence blocks 1 and 2 there were tandem repeats of an 8 bp equine-specific sequence TGTGCACC, and the number of tandem repeats differed among individual horses....
[A comparison of cardiac stroke volume determination using the thermodilution method and PW-Doppler echocardiography for the evaluation of systolic heart function in the horse]. In 14 horses without heart disease stroke volume determination were established by pulsed wave doppler echocardiography. Thermodilution and doppler echocardiography were used simultaneously. The doppler echocardiographic volume determinations were carried out in left and right outflow tracts. Echocardiographically Velocity Time Integral, Maximum Flow Velocity, Mean Flow Velocity and Acceleration Time were ascertained. To be able to compare heart volumes of horses with different body weight stroke volume was applied to 1 kg of body weight (= heart index). Heart Index determined with thermodilut...
Temperature and pH effects on the oxygen equilibrium curve of the thoroughbred horse. A new oxygen equilibrium curve is defined for the Thoroughbred horse under standard conditions of 37 degrees C, pH = 7.4 and PCO2 = 5.33 kPa. The "standard" P50 for the Thoroughbred is, at 2.83 +/- 0.04 (SE of mean) kPa, significantly lower than that found for the Hanoverian horse (3.17 +/- 0.03 kPa) by Clerbaux et al. (Can. J. Vet. Res. 50: 188-192, 1986), and lower than other values for horses in the literature. Using data from Butler et al. (J. Exp. Biol. 179: 159-180, 1993), curves were also constructed, in vitro, under simulated conditions of intense exercise to examine the individual eff...
Comparative aspects of Na(+)-K+ and Ca(2+)-Mg2+ ATPase in erythrocyte membranes of various mammals. This work is a comparative study of Na(+)-K+ and Ca(2+)-Mg2+ ATPase associated with the erythrocyte plasma membranes in different mammals. The method used to test the activity of these enzymes is based on quantitative measurements of ADP released during the reaction with HPLC: the chromatographic type is an Ion-Pair Reversed Phase. We have found that the levels of Ca2+ stimulated ATPase are higher than those of Na(+)-K+ ATPase in red blood cells of all the different mammalian species, with the only exception being lamb erythrocytes where the values of both the ATPase activities are almost equa...
Pregnancy-associated endometrial expression of antileukoproteinase gene is correlated with epitheliochorial placentation. Uterine expression of the mRNA encoding antileukoproteinase (ALP) is highest in pig uterus during mid- to late pregnancy, suggesting a stage of pregnancy-dependent role for this elastase/cathepsin G protease inhibitor in feto-maternal interactions. To examine a potential relationship between uterine synthesis of ALP and the type of placentation in mammalian species, the expression of ALP mRNA and/or protein in pregnant mares, cows, rats, and mice was evaluated. Genomic DNA and mRNA hybridization analyses were performed using a porcine ALP cDNA as probe. The concentration of ALP protein in repr...
Light chain isotype regulation in the horse. Characterization of Ig kappa genes. Horse Ig kappa genes have been characterized to determine whether there may be a structural basis for the low level of kappa expression in this species. The overall organization of the J kappa-C kappa locus is remarkably similar to that of the mouse and human loci. A single C kappa exon is separated by 2.9 kb from five J kappa segments, four of which seem functional and three of which are associated with canonical recombination signal sequences. A highly conserved intron enhancer was identified upstream of the C kappa exon and a single restriction fragment in horse genomic DNA hybridized stron...
A subpopulation of morphologically normal, motile spermatozoa attach to equine oviductal epithelial cell monolayers. Attachment of spermatozoa to oviductal epithelial cells (OEC) may be a prefertilization event in some species. We tested the hypothesis that spermatozoa that attach to equine OEC monolayers are a selected subpopulation of the initial inseminate, containing a higher proportion of morphologically normal, motile cells than the inseminate. Washed stallion spermatozoa were cocultured with monolayers of OEC or monolayers of Vero cells, and controls were incubated in wells coated with basement membrane extract (Matrigel [Mgel]) or in plastic (uncoated) wells. Unattached spermatozoa were removed by ri...
Characterization of monoclonal antibodies specific for equine homologues of CD3 and CD5. Two monoclonal antibodies (mAb), UC F6G-3 and UC F13C-5, were characterized as being specific for the apparent equine homologues of CD3 and CD5, respectively. Both antibodies exhibited characteristics of pan-T-lymphocyte markers based upon immunohistology and two-colour flow cytometry. UC F6G-3 precipitated a complex of proteins (up to seven) with molecular weights ranging from 18,000 to 42,000, similar to the human and murine CD3 complex. Upon further dissociation of the precipitated complex, two proteins were identified with molecular weights of 22,000 and 27,000. Immobilized UC F6G-3 was ef...
Models of the three-dimensional structures of echidna, horse, and pigeon lysozymes: calcium-binding lysozymes and their relationship with alpha-lactalbumins. Similarities in amino acid sequences, three-dimensional structures, and the exon-intron patterns of their genes have indicated that c-type lysozymes and alpha-lactalbumins are homologous proteins, i.e., descended by divergent evolution from a common ancestor. Like the alpha-lactalbumins, echidna milk, horse milk, and pigeon eggwhite lysozymes all bind Ca(II). Models of their three-dimensional structures, based on their amino acid sequences and the known crystal structures of domestic hen eggwhite and human lysozymes and baboon and human alpha-lactalbumins, have been built. The several structur...
Is dentition an accurate indication of the age of a horse? It is widely accepted that the age of a horse can be determined from an examination of its teeth, but there is no evidence that the accuracy of the systems of ageing used has been validated. A dental record was made of 80 horses of known age. There was a good correlation between the actual and apparent age of the horses up to five years, but older horses showed much greater variability and accuracy declined markedly after 11 years of age. The disappearance of the 'cup', but not the 'mark', proved to be one of the more reliable features. The average age at which the dental star appeared was one...
Effect of body direction on heart rate in trailered horses. To determine whether body direction in a trailer affects the degree to which a horse is excited (and presumably stressed) during transport, heart rates were measured in 8 Thoroughbred geldings transported over a 32-km route of county roads while tethered facing forward or backward in a 4-horse stock trailer. Heart rates also were measured on the horses while they were tethered facing forward or backward in the same trailer while it was parked. Heart rates decreased during the first 10 minutes for both groups, and remained stable after the first 15 minutes. Heart rates were not significantly di...
The structure, innervation and location of arteriovenous anastomoses in the equine foot. In the foot of the horse, arteriovenous anastomoses (AVAs) of epithelioid type occurred in the dermis of the coronary band, in the coronary and terminal papillae, in neurovascular bundles and at the entrance to and along the length of the dermal laminae. A particular feature of the epithelioid segment of AVAs in the horse, compared with that of other species, was the height and surface complexity of many of the endothelial cells. They extended into the lumen, forming undercut and tunnel-like areas which correlated with the characteristic surface marking of AVAs observed in vascular casts. The ...
Influence of estrous cycle stage on adhesion of Streptococcus zooepidemicus to equine endometrium. Equine endometria representative of Kenney's categories I, II, and III were incubated in vitro with phosphate buffer, Streptococcus pneumoniae, or S zooepidemicus. Endometrial tissues from mares in estrus and diestrus were first categorized according to Kenney's classification, then were tested for adherence of S pneumoniae and S zooepidemicus to the epithelia. Bacteria were not observed when the endometrial tissue was incubated with phosphate buffer or S pneumoniae. There was no statistical difference in attachment of S zooepidemicus to endometrial tissue from mares in estrus or diestrus if e...
Comparative aspects of the strength of pulmonary capillaries in rabbit, dog, and horse. In previous studies of rabbit and dog lung, we demonstrated stress failure of pulmonary capillaries at high transmural pressures (Ptm). The Ptm necessary to elicit stress failure was 40 cmH2O higher in dog than rabbit, and the total blood-gas barrier (BGB) thickness was greater in dog than rabbit. This suggests that stress failure may be related to BGB thickness, and is consistent with the Laplace relationship which states that wall stress is proportional to capillary radius but inversely proportional to wall thickness. In the present studies, we compared BGB thickness and an index of capillar...
Temporal changes in concentrations of amino acids in plasma and whole blood of healthy neonatal foals from birth to two days of age. Temporal changes, as well as differences in distribution, in concentrations of 24 amino acids in plasma and whole blood of neonatal foals were determined from birth to 2 days of age. In addition, differences in concentrations of amino acids in plasma between mare and foal pairs were determined at birth. Significant (P < 0.05) hypoaminoacidemia existed for 15 amino acids in plasma of foals at birth, compared with mares (paired t-test). Concentrations of 7 amino acids (aspartate, glutamate, glutamine, glycine, hydroxyproline, phenylalanine, proline) in plasma of foals were higher (P 0.05). S...
Effect of helium-induced ventilatory unloading on breathing and diaphragm EMG in awake ponies. Two questions were addressed in this study: 1) Does respiratory resistive unloading (inspired O2 fraction = 0.21, inspired He fraction = 0.79) elicit a compensatory reduction in stimulation of the diaphragm? 2) Do diaphragm and lung afferents contribute to compensatory responses to unloading? Ten intact (I), five diaphragm-deafferented (DD), four hilar nerve-denervated (HND), and seven DD+HND adult ponies were studied at rest and during mild and moderate treadmill exercise. During steady-state unloading at rest, duration of the diaphragm electromyogram (EMGdi) was less (P < 0.05) than contr...
Skeletal muscle characteristics in red blood cell normovolaemic and hypervolaemic standardbred racehorses. Muscle biopsy specimens from the middle gluteal muscle were studied in 16 red blood cell hypervolaemic (Group HV) and 19 normovolaemic (Group NV) Standardbred racehorses. All horses were stallions, 4-8 years old and having similar mean racing performance values, as described by an individual selection index value. All horses raced regularly but those in Group HV did not perform as expected and were therefore referred to the clinics for exercise tolerance testing. Muscle biopsy specimens were analysed for fibre type distribution (Type I, IIA and IIB), fibre area and relative fibre area. In addi...
Concentrations of amino acids in plasma and whole blood in response to food deprivation and refeeding in healthy two-day-old foals. Concentrations of amino acids in plasma and whole blood in response to 10 hours of food deprivation were determined in healthy 2-day-old foals (n = 8) and were compared with control values in foals of the same age (n = 8) allowed free access to suckle. In addition, response of concentrations of amino acids in plasma to 15 minutes of free-access suckling was determined at the end of the 10-hour period in both groups. Response of 13 amino acids in plasma of food-deprived foals was significantly (P < 0.05) different, compared with that in control foals. Concentrations of 3 amino acids (alanine...
Variation in expression of MHC class II antigens on horse lymphocytes determined by MHC haplotype. A panel of monoclonal antibodies was used to characterize the expression of equine Major Histocompatibility Complex (MHC) class II antigens on lymphocytes of horses of different MHC types. MHC class II antigen expression was compared between adult horses and foals, and the level of expression of MHC class II antigens on horse T cell subpopulations was also determined. Peripheral blood lymphocytes (PBL) from young and adult healthy horses of different MHC haplotypes were labeled with the antibodies and assayed by single- and two-color immunofluorescence flow cytometry. A variation in the expres...
