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Topic:Cells
The study of cells in horses encompasses the examination of various cell types and their functions within the equine body. Cells are the basic structural and functional units of life, and in horses, they contribute to numerous physiological processes, including growth, repair, and immune responses. Different cell types, such as red blood cells, white blood cells, and muscle cells, each perform specific roles that are vital for maintaining the health and homeostasis of the horse. This topic includes research on cellular mechanisms, cellular responses to disease or injury, and the application of cellular biology in equine medicine. This page compiles peer-reviewed research studies and scholarly articles that explore the structure, function, and significance of cells in equine biology and health.
The basement membrane at the equine hoof dermal epidermal junction. In the equine hoof, the basement membrane connects the heavily keratinised hoof wall to the dense connective tissue of the distal phalanx, a region able to withstand considerable mechanical stress. This study investigated the properties of this important anatomical and physiological structure. In contrast to haematoxylin and eosin, the connective tissue stains, periodic acid Schiff, periodic acid silver methenamine and Azan showed good resolution of lamellar basement membrane. The lamellar basement membrane cross-reacted with mouse monoclonal antibodies raised against human laminin, thereby pr...
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...
Molecular cloning and expression of two horse pancreatic cDNA encoding colipase A and B. Pancreatic colipase plays an essential role in the intestinal fat digestion by anchoring lipase on lipid/water interfaces in the presence of bile salts. In contrast to other species, two molecular forms of colipase, A and B, have been found in horse. The two corresponding cDNAs were isolated from a horse pancreatic library and their nucleotide sequences were determined. Moreover, for the first time, active colipase has been obtained after transfection of COS cells by either colipase A or B cDNA.
Interaction of equine spermatozoa with oviduct epithelial cell explants is affected by estrous cycle and anatomic origin of explant. Regulation of attachment of equine spermatozoa to homologous oviduct epithelium was investigated by co-culture of spermatozoa with oviductal epithelial cell explants. Stallion spermatozoa were incubated with explants derived from the isthmus and ampulla of follicular, postovulatory, and diestrous mares. Steroid treatments (estradiol, progesterone, or control) were applied across all explant groups. Estimates of motility and total numbers of attached spermatozoa were made 0.5, 24, and 48 h after initiation of co-culture. Equine spermatozoa attached by their rostral acrosomal region to both cili...
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...
Substance P and calcitonin gene-related peptide-like immunoreactive nerve fibers in lungs from adult equids. Distribution of pulmonary nerves immunoreactive for either substance P or calcitonin gene-related peptide was determined, using immunohistochemical methods on healthy lungs from adult equids. The overall patterns of distribution of substance P and calcitonin gene-related peptide-like immunoreactivity were similar. Distribution of immunoreactive nerves was not uniform throughout the lungs; nerve fibers immunoreactive for these peptides were more frequently observed near the hilus of the lung than in the caudal lobes or in the periphery of the lung. Nerve fibers immunoreactive for substance P or...
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...
Inhibition of binding, entry, or intracellular proliferation of Ehrlichia risticii in P388D1 cells by anti-E. risticii serum, immunoglobulin G, or Fab fragment. The effects of equine antiserum, immunoglobulin G (IgG) specific for Ehrlichia risticii, and its Fab fragment on E. risticii binding to, internalization into, and proliferation in P388D1 cells were studied by immunofluorescence flow cytometry. Anti-E. risticii equine serum or IgG inhibited E. risticii at a stage beyond binding and internalization. In contrast, monovalent anti-E. risticii equine Fab fragments inhibited E. risticii binding and internalization into P388D1 cells. In the presence of control equine serum, IgG, or its Fab fragment, E. risticii cells were bound, were internalized and ...
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 ...
Polymorphic expression of an equine T lymphocyte and neutrophil subset marker. This report describes the further characterization of a group of antibodies which have been assigned to Workshop Cluster 1 by the First International Workshop on Equine Leucocyte Antigens. These antibodies recognize a 22 kDa antigen, which is present on a large subset of T lymphocytes and neutrophils, and on medullary thymocytes. The antigen is polymorphic in its expression, and three equine phenotypes could be identified using the described antibodies. The function and homology of the antigen recognized by these antibodies are unknown.
Report of the First International Workshop on Equine Leucocyte Antigens, Cambridge, UK, July 1991. The First International Workshop on Equine Leucocyte Antigens was organized and convened for the purposes of identifying immunologically relevant cell surface molecules of equine leucocytes and establishing a system of nomenclature for those molecules. Participating members of the workshop represented the majority of laboratories world-wide engaged in the tasks of production and characterization of equine leucocyte and lymphocyte markers using monoclonal antibodies. The workshop confirmed the identification of several equine CD molecules described previously by individual laboratories, and in ...
Chondrocyte-fibrin matrix transplants for resurfacing extensive articular cartilage defects. Cartilage resurfacing by chondrocyte implantation, with fibrin used as a vehicle, was examined in large (12 mm) full-thickness articular cartilage defects in horses. Articular chondrocytes, isolated from a 9-day-old foal, were mixed with fibrinogen and injected with thrombin, in a 1:1 mixture, into 12 mm circular defects on the lateral trochlea of the distal femur of eight normal horses. The contralateral femoropatellar (knee) joint served as a control in which the defect was left empty. Synovial fluid from the femoropatellar joints was sampled on days 0, 4, 7, 30, 120, and 240 postoperatively...
Intravascular leukostasis and systemic aspergillosis in a horse with subleukemic acute myelomonocytic leukemia. Leukemia is a neoplastic disease of one or more of the cell types of the hemopoietic system and is rarely diagnosed in the horse. This report describes a case of subleukemic acute myelomonocytic leukemia in an 11-year-old gelding. Preliminary cytological diagnosis was supported by two types of laboratory investigations. Cytochemical characterization of blood and bone marrow neoplastic cells was consistent with a myelomonocytic origin. Neoplastic blast cells in peripheral blood were labeled by monoclonal antibodies specific for cell surface molecules of horse granulocytes, but they were not lab...
Down-regulation followed by re-expression of equine CD4 molecules in response to phorbol myristate acetate. The regulatory effects of phorbol myristate acetate (PMA) on the expression of the CD4 molecule on horse T cells were investigated. On both peripheral blood lymphocytes and thymocytes, PMA resulted in a rapid and transient down-regulation of equine CD4 expression, but had no such effect on the surface expression of equine CD5, CD8 or major histocompatibility complex (MHC) class I and class II molecules. Over 75% of the surface CD4 molecules per cell were lost after a 4 h exposure to PMA at 37 degrees C. The regulation of equine CD4 expression induced by PMA was temperature dependent and revers...
P2 protamines are phosphorylated in vitro by protein kinase C, whereas P1 protamines prefer cAMP-dependent protein kinase. A comparative study of five mammalian species. P1 protamines isolated from ejaculated human, stallion, bull, boar and ram spermatozoa and P2 protamines from human and stallion spermatozoa were subjected, after alkaline phosphatase treatment, to in vitro phosphorylation reactions using cAMP-dependent protein kinase (PKA) and protein kinase C (PKC). All P1 protamines were phosphorylated by PKA, whereas P2 protamines were phosphorylated only by PKC. In addition, human, stallion and boar, but not bull and ram, P1 protamines were phosphorylated by PKC. After phosphoamino acid analysis, the protamines showing positive signals for phosphoserine (...
An equine B cell surface antigen defined by a monoclonal antibody. A surface antigen of equine B lymphocytes was identified using the Equine Leucocyte Antigen Workshop antibody WS 65. This marker was expressed on almost all equine B cells, but not on T cells, granulocytes or thymocytes. WS 65 strongly stained cells in the follicular areas of lymph nodes and cells in the splenic nodules when tested on frozen tissue sections by immunohistochemistry. Equine leukemic T cells were not labeled by WS 65, and neither were the cells from a horse with B cell leukemia, although these latter cells carried surface immunoglobulin. Immunoprecipitation of lymphocyte membrane...
Structural organization and neuropeptide distributions in the equine enteric nervous system: an immunohistochemical study using whole-mount preparations from the small intestine. The architecture and neurochemistry of the enteric nervous system was studied by use of whole-mount preparations obtained by microdissection of the horse jejunum. A myenteric plexus and two plexuses within the submucosa were identified. The external submucosal plexus lying in the outermost region of the submucosa had both neural and vascular connections with the inner submucosal plexus situated closer to the mucosa. Counts of neurones stained for NADH-diaphorase demonstrated the wide variation in size, shape and neurone content of individual ganglia in both the external and internal submucosal...
Characterization of muscarinic receptor subtype mediating contraction and relaxation in equine coronary artery in vitro. In coronary arterial rings isolated from horses, 10(-8)-10(-6) mol/l acetylcholine (ACh) induced concentration-dependent contractions which were potentiated by the removal of endothelium and by pretreatment with L-nitro-arginine (LNAG) or methylene blue (MB). Relatively lower concentrations of ACh (10(-14)-10(-8) mol/l) induced relaxation when the coronary rings were contracted by phenylephrine (PE). ACh-induced contractions in the coronary rings without endothelium were competitively inhibited by each muscarinic subtype selective antagonist in the following order of potency: 4-diphenylacetoxy...
Cellular and viral specificity of equine infectious anemia virus Tat transactivation. Lentiviruses vary in their dependence on a functional tat gene during their viral life cycle. To begin to understand the viral and cellular parameters controlling equine infectious anemia virus (EIAV) transactivation, we investigated Tat function and Tat and LTR structural requirements necessary for successful transactivation. EIAV Tat expression was required for detection of viral antigens from a full-length provirus. The level of transactivation by EIAV Tat as measured by LTR-CAT assays correlated well with viral antigen expression. Using horse/mouse somatic cell hybrids (SCH), a single SCH ...
Studies on glycoprotein-derived carbohydrates. This research focuses on the study of glycoproteins, specifically investigating their carbohydrate chains and their various functions in living organisms. The article highlights the challenges in isolating specific carbohydrate chains […]
Identification of phosphoseryl residues in protamines from mature mammalian spermatozoa. Protamines isolated from ejaculated human, stallion, bull, boar, and ram spermatozoa were subjected to phosphoserine conversion reaction and protein sequencing. Phosphoserines were detected as S-ethylcysteines. Endogenously phosphorylated protamines have previously been found only in ejaculated human sperm. In this study, we demonstrate that ejaculated sperm from other species also contain protamines phosphorylated at serine residues. In P1-protamines, the endogenously phosphorylated serines were located at the N-terminal region in all species studied, whereas in major forms of human and stall...
The transition from inhomogeneous to homogeneous kinetics in CO binding to myoglobin. Heme proteins react inhomogeneously with ligands at cryogenic temperatures and homogeneously at room temperature. We have identified and characterized a transition from inhomogeneous to homogeneous behavior at intermediate temperatures in the time dependence of CO binding to horse myoglobin. The turnover is attributed to a functionally important tertiary protein relaxation process during which the barrier increases dynamically. This is verified by a combination of theory and multipulse measurements. A likely biological significance of this effect is in the autocatalysis of the ligand release p...
Lipid analysis of lavage samples from the equine guttural pouch (auditory tube diverticulum). The guttural pouch is a large, air-filled diverticulum of the auditory tube, present in the horse and other species. Lipid analysis of saline lavage from the equine guttural pouch has demonstrated the presence of phospholipids and neutral lipids in amounts that are variable but consistently greater than in any other species described. A stain specific for choline-containing phospholipids has demonstrated the presence of phospholipid-containing vesicles only within the cells of subepithelial, seromucoidlike glands, suggesting that these cells incorporate phospholipids in their secretions. The f...
Histologic and ultrastructural changes after large-colon torsion, with and without use of a specific platelet-activating factor antagonist (WEB 2086), in ponies. The role of platelet-activating factor (PAF) in mediating the colonic damage that develops after large-colon torsion was studied in 14 ponies. Morphologic changes in areas of the ascending colon and selected abdominal and thoracic viscera after 1 hour of large-colon torsion and 3 to 5 hours of reperfusion were determined, as well as the protective effects of systemic administration of a specific PAF antagonist (WEB 2086). Ponies were selected then allocated at random and in equal numbers to 2 groups that received 1 of 2 treatments prior to induction of large-colon torsion: group 1--control (sa...
Rapid refolding of native epitopes on the surface of cytochrome c. Refolding of surface epitopes on horse cytochrome c has been measured by monoclonal antibody binding. Two antibodies were used to probe re-formation of native-like surface structure: one antibody (2B5) binds to native cytochrome c near a type II turn (residue 44) while the other (5F8) binds to a different epitope on the opposite face of the protein near the amino terminus of an alpha-helical segment (residue 60). The results show that within the first approximately 100 ms of refolding all of the unfolded protein collapses to native-like folding intermediates that contain both antibody binding ...
The cytology of squamous cell carcinomas in domestic animals. A series of 40 tumors with a proven diagnosis of squamous cell carcinoma for which both histology and cytology were available were classified according to their histologic appearance as well differentiated, moderately differentiated, and poorly differentiated. The Romanowsky-stained cytology specimens were reviewed. When available, Papanicolaou-stained smears were included. The cytologic findings for each of the 3 groups are described, and the most significant findings are photographically illustrated.
Expression of functional protease and subviral particles by vaccinia virus containing equine infectious anaemia virus gag and 5′ pol genes. Cells infected with vaccinia viruses expressing the equine infectious anaemia virus (EIAV) gag gene (VGag) or gag plus the 5' pol encoding protease (VGag/PR) were evaluated with monoclonal antibody to a p26 capsid protein linear epitope (QEISKFLTD). Both recombinant viruses expressed Gag precursor protein (55K) whereas only VGag/PR expressed a detectable Gag-Pol fusion protein (82K) with a functional protease, shown by subviral particles containing processed p26. Horses inoculated with VGag/PR produced antibodies reactive with EIAV Gag proteins.
