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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.
Cardiac rod body: hypertrophic Z-line in an aged pony. Numerous rod bodies were found in a heart sample from a 33-year-old pony by a conventional electron-microscopic technique. The rod bodies were concentrated in localized areas of both atria and ventricles, without a specific pattern of distribution. The rods appear to have a typical crystalline-like structure which presumably contains actin backbone filaments and alpha-actinin as major protein constituents. Diminution, fragmentation, and disorganization of the myofibrils, random expansion of electron-dense materials, especially at the fasciae adherens of the intercalated disc, an increase of in...
Cytofluorescent assay to quantify adhesion of equine spermatozoa to oviduct epithelial cells in vitro. To facilitate the study of interactions between equine spermatozoa and homologous oviduct epithelial cells, we developed an assay to count labelled spermatozoa bound to oviduct epithelial cell (OEC) monolayers and used the assay to compare the binding ability of spermatozoa from different stallions. Washed spermatozoa from three stallions were incubated with the fluorochrome Hoechst 33342 (5 micrograms/ml) for 1 min. Spermatozoa were then layered over confluent monolayers of oviduct epithelial cells in 2 cm2 culture wells. Coculture treatments comprised five concentrations of spermatozoa (10(5...
Equine infectious anemia virus replication is upregulated during differentiation of blood monocytes from acutely infected horses. Equine infectious anemia virus is a lentivirus that replicates in mature tissue macrophages of horses. Ponies were infected with equine infectious anemia virus. During febrile episodes, proviral DNA was detectable, but viral mRNA was not detectable. As cultured blood monocytes from these ponies differentiated into macrophages, viral expression was upregulated. In situ hybridization confirmed that viral transcription occurred in mature macrophages.
Fumonisins, mycotoxins of increasing importance: their nature and their effects. The fumonisins (FBs) are a group of closely related mycotoxins that are prevalent in maize. They were isolated from strains of Fusarium moniliforme (Sheldon), which were implicated in the aetiology of human oesophageal cancer in the Transkei, South Africa. Their discovery explained the cause of equine encephalomalacia, or "hole in the head" syndrome, when it was found by feeding trials in horses that they elicited the disease. Subsequently, they were found to cause hepatic cancer in rats and pulmonary oedema in pigs, with most animal species tested showing liver and kidney damage. FB1 is the m...
Effect of growth factors on the characteristics of cells associated with equine wound healing and sarcoid formation. Wound healing in equidae is delayed and more complicated than in other species. These complications arise from a condition known as exuberant granulation tissue formation. The lower limb of the horse is frequently slower to heal than other parts of the body and has a particular tendency to produce excess (exuberant) granulation tissue. Sarcoids are tumor-like lesions of the skin which often appear at the site of wounds. This study compared the growth characteristics of the sarcoid and granulation tissue-derived cells with normal dermal fibroblasts grown from primary cell cultures. All three ce...
Biosynthesis and distribution of leucocyte elastase inhibitor. Production of recombinant inhibitor. The horse leucocyte elastase inhibitor (HLEI), present in neutrophils, monocytes and bone marrow cells, is apparently a cytoplasmic protein which is not released from cells even in response to stimulation with lipopolysaccharide, phorbol ester, tumour necrosis factor alpha, interleukin-1 or elastin degradation products. Although no expression of the inhibitor was detected in neutrophils, both monocytes and bone marrow cells were efficient in its synthesis. Using a new expression vector pREST5d, recombinant inhibitor was produced in a large quantity in a soluble form, with a yield of 88 mg per ...
Evaluation of a porous bovine collagen membrane bandage for management of wounds in horses. To evaluate the effect of a porous bovine-derived collagen membrane (PBCM) on the rates of wound healing, cellular events, presence of granulation tissue, and appearance at termination of the study in surgically created full-thickness cutaneous wounds of the distal portion of the extremities of horses. Methods: Treated wounds (n = 12) received a PBCM dressing and control wounds were covered with a nonadherent dressing. Forelimbs and hind limbs were cross paired; the right forelimb and left hind limb always received the same dressing application, as did the left forelimb and right hind limb. Li...
Effect of coculture with stallion spermatozoa on de novo protein synthesis and secretion by equine oviduct epithelial cells. Adhesion of equine spermatozoa to homologous oviduct epithelial cells (OEC) in vitro results in specific changes in spermatozoa and OEC function. To test the hypothesis that adhesion of spermatozoa affects protein synthesis and secretion by OEC, the following treatment groups were established in culture: OEC with culture medium only; control spermatozoa in culture medium only; OEC in coculture with spermatozoa; and OEC and spermatozoa in coculture, but physically separated by a microporous membrane. The experiment was replicated within each of 4 ejaculates from 3 stallions. De novo protein sec...
Initiation of transcription and nucleologenesis in equine embryos. The time of activation of the embryonic genome (maternal-embryonic transition) in equine embryos was investigated by assessing incorporation of 3H-uridine and nucleolar development. In Experiment 1, embryos were recovered from the oviduct (n = 15) and the uterus (n = 3). Recovered embryos were assessed for morphologic development and quality score. Recovered embryos with less than 8 cells (two cells, n = 4; four cells, n = 5; five cells, n = 2) were incubated with 3H-uridine (560 microCi/ml) for 10 hr, while eight-cell embryos (n = 2), morulae (n = 2), and blastocysts (n = 3) were incubated wi...
Segmented filamentous bacteria associated with lymphoid tissues in the ileum of horses. Segmented filamentous bacteria preferentially attached to the follicle-associated epithelium overlying the lymphoid tissue in samples of the terminal ileum from seven horses examined by scanning electron microscopy. The bacteria adhered to the apical membrane of the enterocytes by a holdfast segment. Each filament tended to be of uniform diameter, but the filaments ranged from 0.7 to 1.4 microns in diameter. The bacteria were usually absent from the adjacent villous epithelium.
An immunohistochemical study of three equine pulmonary granular cell tumors. Granular cell tumor (GCT) is a morphologic designation for tumors of varied histogenesis. Most GCTs in human beings are derived from Schwann cells, and rat meningeal GCTs are believed to originate in the neural crest. Three equine pulmonary GCTs from aged horses were studied immunohistochemically with primary antibodies directed against vimentin, cytokeratins (AE1/AE3), S-100, Leu 7, desmin, and neuron-specific enolase (NSE) using a steptavidin-biotin procedure. All three tumors stained similarly with strong and diffuse staining of neoplastic cells for vimentin and S-100 and negative staining ...
Protein tyrosine phosphorylation in equine platelets: the effect of stimulation by thrombin and platelet-activating factor (PAF). Protein tyrosine phosphorylation (PTP) in thrombin- and platelet-activating factor (PAF)-stimulated equine platelet activation was investigated in the absence and presence of 2 protein tyrosine kinase inhibitors (PTKIs), methyl 2,5-dihydroxycinnamate (MDHC) and genistein. Washed equine platelets aggregated irreversibly in response to thrombin or PAF in an agonist concentration dependent fashion. MDHC produced an MDHC concentration and time dependent inhibitory effect on rate and extent of thrombin- and PAF-induced aggregations, whereas the effect of genistein on the same parameters was only ge...
Causes of differences in respiration rate of hepatocytes from mammals of different body mass. Resting O2 consumption of hepatocytes isolated from mammals ranging in mass from 20-g mice to 200-kg horses decreases with increasing body mass. The substrate oxidation system increases in activity with increasing body mass and mitochondrial proton leak and phosphorylation system decrease in activity, resulting in a higher mitochondrial membrane potential in hepatocytes from larger mammals. The absolute rates of O2 consumption due to nonmitochondrial processes, substrate oxidation, mitochondrial proton leak, and the phosphorylation system decrease with increasing body mass. These decreases are...
Molecular cloning of equine interleukin-1 alpha and -beta cDNAs. Equine interleukin-1 alpha (IL-1 alpha) and IL-1 beta were molecularly cloned to establish a basis for research on inflammatory and immune responses in the horse. Equine peripheral blood mononuclear cells (PBMC) were stimulated with lipopolysaccharide (LPS), and cDNA clones of equine IL-1 alpha and IL-1 beta covering the whole coding sequences were isolated from them. These equine IL-1 alpha and IL-1 beta clones contained open reading frames encoding 271 and 269 amino acids, respectively. The deduced amino acid sequence of equine IL-1 alpha showed 71.6% and 60.2% similarity with that of human ...
The unfolding thermodynamics of c-type lysozymes: a calorimetric study of the heat denaturation of equine lysozyme. The energetics of the temperature-induced unfolding of equine lysozyme was studied calorimetrically and compared with that of two structurally homologous proteins: hen egg white lysozyme and alpha-lactalbumin. The structure of each of these proteins is characterized by the presence of a deep cleft that divides the molecule into two regions called the alpha and beta domains. In equine lysozyme and alpha-lactalbumin the latter domain specifically binds Ca2+. It is shown that, in contrast to hen egg white lysozyme in which the alpha and beta domains unfold as a single cooperative unit, in equine ...
Beta-thiopropionyl cytochromes c modified at lysyl residues: preparation and characterization of the monosubstituted horse cytochromes c. beta-Thiopropionyl derivatives of horse cytochrome c singly modified at each of 18 different lysine epsilon-amino groups have been prepared using sulfosuccinimidyl-2-(biotinamido)ethyl-1,3-dithiopropionate and purified to homogeneity by high-pressure liquid chromatography. These derivatives were characterized by determination of: (i) the location of the modification; (ii) reduction potentials; (iii) visible and NMR spectra: and by (iv) measurement of electron transfer activity with cytochrome-c oxidase. No significant changes in structure were indicated, except for the ferric forms of the deri...
In vitro Catabolism of very low density lipoproteins from horse (Equus caballus) by the action of autologous lipoprotein lipase. Incubation of equine very low density lipoproteins with lipoprotein lipase isolated from horse postheparin plasma resulted in the formation of lipoproteins of a higher density. Lipoproteins isolated after incubation and plasma lipoproteins had a different chemical composition and triacylglycerol fatty acid pattern. In vitro-obtained low density lipoproteins contained substantially more phospholipids and triacylglycerols but significantly less cholesteryl esters than native low density lipoproteins. Comparing the triacylglycerol fatty acid pattern of plasma very low density lipoproteins and in ...
Ultrastructure of the secretory endometrium during oestrus in young maiden and foaled mares. Cyclical accumulation of uterine fluid occurs during oestrus and is often seen in excessive volumes in mares considered susceptible to endometritis. Since the mechanisms behind the formation of free uterine fluid remain to be clarified, the fine structure of the secretory equine endometrium was studied in biopsies collect during videoendoscopy from 14 endometritis-free, 4-9-year-old mares during oestrus. A distinct oedema of the tunica mucosa was evident. The surface epithelium had both ciliated and nonciliated cells and, particularly at the uterine body, often presented intra-epithelial macro...
Localisation of 15-hydroxy prostaglandin dehydrogenase (PGDH) and steroidogenic enzymes in the equine placenta. 15-hydroxy prostaglandin dehydrogenase (PGDH) is the critical enzyme that determines metabolism of primary prostaglandins. Its expression is determined in part by steroid hormones, particularly progesterone, formed from delta(5) steroids through 3beta-hydroxysteroid dehydrogenase (3beta-HSD) activity. To assess whether the regulation of PGDH might occur in a paracrine, autocrine or intracrine fashion, we used immunohistochemistry (IHC) to determine the localisation of key steroidogenic enzymes in the equine placenta and compared these patterns to the distribution of immunoreactive (IR-) PGDH. ...
Characteristics of equine herpesvirus 1 glycoproteins expressed in insect cells. A series of recombinant baculoviruses containing genes for glycoproteins C, D, H and L of equine herpesvirus 1 (EHV-1) have been constructed, and the EHV-1 products characterised by gel electrophoresis and immunoblotting. The EHV-1 glycoproteins expressed in insect cells were similar but not identical in apparent sizes to those expressed in EHV-1 infected mammalian cells. Each of the EHV-1 products was recognised by convalescent equine sera, indicating that they were all targets for an equine immune response. Mice immunised with baculovirus-expressed EHV-1 gD and gC acquired an enhanced abilit...
The maternal leucocyte response to the endometrial cups in horses is correlated with the developmental stages of the invasive trophoblast cells. Invading trophoblasts form endometrial cups in the endometrium of the pregnant mare. In the present study we characterized the maternal leucocyte response to endometrial cups from their formation to their regression. The maternal leucocyte response was correlated with the stages of trophoblast development. (1) Aggregates of CD4+ and CD8+ cells were present between the migrating and differentiating endometrial cup trophoblasts and surrounding the forming endometrial cups. (2) Numbers of CD4+ cells within the mature endometrial cups were much reduced. At the periphery of the endometrial cups CD4...
Interleukin-1-mediated regulation of plasminogen activation in pregnant mare serum gonadotropin-primed rat granulosa cells is independent of prostaglandin production. This study examines the effects of interleukin-1 (IL-1) on plasminogen activator (PA) activity and prostaglandin (PG) E production in pregnant mare serum gonadotropin (PMSG)-primed granulosa cells and the potential involvement of PGE in the regulation of ovarian plasminogen activation. Methods: Granulosa cells were obtained from PMSG-primed rat (27-day-old) ovaries and cultured in serum-free conditions for 48 hours in the absence or presence of IL-1 beta (10 ng/mL) with and without transforming growth factor-beta 1 (10 ng/mL). Cellular PA activity was measured through the conversion of plasmin...
Sr2+ can become incorporated into an agonist-sensitive, cytoplasmic Ca2+ store in a cell line derived from the equine sweat gland epithelium. We have explored the properties of a Ca(2+)-dependent cell-signalling pathway that becomes active when cultured equine sweat gland cells are stimulated with ATP. The ATP-regulated, Ca(2+)-influx pathway allowed Sr2+ to enter the cytoplasm but permitted only a minimal influx of Ba2+. Experiments in which cells were repeatedly stimulated with ATP suggested that Sr2+, but not Ba2+, could become incorporated into the agonist-sensitive, cytoplasmic Ca2+ store. Further evidence for this was provided by experiments using ionomycin, a Ca2+ ionophore which has no affinity for Sr2+.
Partial sequence of the equine immunoglobulin epsilon heavy chain cDNA. In order to isolate a part of the immunoglobulin E (IgE) heavy chain cDNA of the horse, primers have been designed based upon well conserved sequences in humans, sheep and rats. The PCR resulted in a 500 bp fragment which hybridised with a human IgE constant region probe. The fragment was cloned and sequenced and its derived protein sequence compared with the corresponding sequences in humans, sheep and mice. Most amino acids common to these three species are also shared by the horse.
Microscopic anatomy of the equine skin with special reference to the dermis. We have observed and re-evaluated the histology of the skin of the horse, using samples from four Thoroughbreds. The skin was composed of the usual three components: epidermis, dermis and subcutis. In particular, the dermis was found to have three fibrous components: a papillary layer, a reticular layer and a cordovan-leather tissue layer. The cordovan-leather tissue layer was subdivided into a superficial main layer and a deeper accessory layer. The superficial main layer was thick, and present in all of the skin samples. The deeper accessory layer was found in the dorsal and dorso-lateral pa...
Localisation of alkaline phosphatase in equine growth cartilage. The aim of this study was to localise alkaline phosphatase (ALP) activity in equine growth cartilage both histochemically and ultrastructurally. For histochemical studies, full thickness growth cartilage samples were obtained from 6 anatomical sites from 16 horses and ponies ranging in age from 90 d postconception to 12 years of age. For ultrastructural studies, samples were obtained from the lateral trochlear ridge of the distal femur of 3 animals ranging in age from 157 d postconception to 12 months of age. Alkaline phosphatase in histological sections was localised using a substituted napht...
Detection of immunoreactive atrial and brain natriuretic peptides in the equine atrium. The distribution of immunoreactivity (IR) for cardiodilatin/atrial natriuretic peptide (CDD/ANP) and brain natriuretic peptide (BNP) was examined immunohistochemically and immuno-electron-microscopically in the equine atrium, using specific antibodies. In the immunohistochemical studies, IR-CDD/ANP and IR-pBNP-26 (porcine BNP-26 immunoreactivity) was detected in the cytoplasm of the auricular cardiocytes, but IR-hBNP-32 (human BNP-32 immunoreactivity) was not. The double immunogold labelling method for IR-hBNP-28 and IR-pBNP-26 revealed that gold particles of different sizes were located in th...
