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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.
Effect of interleukin 1 on articular cartilage from young and aged horses and comparison with metabolism of osteoarthritic cartilage. The effect of interleukin 1 (IL-1) on equine articular cartilage was investigated, using a cartilage explant culture system. Measurement of [35S]O4 incorporation revealed synthesis of matrix proteoglycan by cartilage to be decreased 45, 59.7, and 37.5% after 1, 3, and 5 days, respectively, in culture in the presence of 5 U of IL-1/ml. There was no change in proteoglycan degradation as determined by measurement of [35S]O4 release into the culture medium. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis of cartilage-conditioned medium indicated that exposure of cartilage to IL-1 caused ...
Vasomotor effects of histamine on bovine and equine basilar arteries in vitro. The vasomotor effects of histamine on isolated bovine and equine basilar arteries were examined. Histamine induced contractions in both these preparations. The maximal response to and pEC50 value for histamine of the equine artery were larger than those of bovine tissue. Similar results were obtained with endothelium-denuded basilar arteries. Diphenhydramine (H1-receptor antagonist) inhibited histamine-induced contractions of the basilar arteries from both species in a concentration-dependent manner and its pA2 values (with 95% confidence limits) were 7.61 (7.39-7.83) and 8.15 (8.01-8.29) for ...
Inhibin activity in the mare and stallion. An overnight double antibody RIA, employing a rabbit antiserum raised to bovine 31 kDa inhibin (rAs-#1989, NICHD) and purified bovine 31 kDa inhibin (bINH-I-90/1, NICHD) as trace and standard, was validated to measure immunoreactive inhibin (iINH) concentrations in equine peripheral plasma, follicular fluid (FF), ovarian vein (OV) plasma, testicular tissue extracts (TTE) and testicular vein (TV) plasma. The dynamic relationship of iINH and follicle stimulating hormone (FSH) was investigated during the estrous cycle of the mare and the annual reproductive cycle of the stallion. In the RIA, para...
The relationship of daily sperm production with number of Sertoli cells and testicular size in adult horses: role of primitive spermatogonia. The number of Sertoli cells is important in spermatogenesis as noted by significant correlations between the number of Sertoli cells and the number of germ cells observed as early as type B2 spermatogonia in the horse. However, the stage within spermatocytogenesis at which these relationships first occur is unclear. The relationships between the number of Sertoli cells and parenchymal weight and the number of germ cells during the mitosis of spermatogenesis were determined in 184 adult horses to identify the developmental stage (that is, the earliest germ cell) at which significant relationshi...
Ultrastructure of the epithelium that lines the ductuli efferentes in domestic equidae, with particular reference to spermatophagy. The epithelium that lines the ductuli efferentes in the horse, donkey and mule has been examined by electron microscopy. The epithelium consists of columnar ciliated and non-ciliated cells. Lymphocytes and macrophages are also present, together with cells that are rich in lipofuscin. These 'lipofuscin-rich' cells are a peculiar feature of the excurrent ducts of Equidae and are characterized by a large number of highly heterogeneous residual bodies. The general morphology of the epithelium and, in particular, of the non-ciliated cells implies that the epithelium is involved in the absorption an...
Immunoreactivity of cytochrome c: antibodies to horse cytochrome c distinguish between sequence-related cytochromes only at the level of the 3-D-structure. It has long been known that antibodies to cytochrome c can distinguish between closely sequence-related cytochromes c. Because the 3-D-structure of the polypeptide chain is virtually identical among eukaryotic cytochromes c, antibody specificity is directed against amino acid substitutions within a common polypeptide folding pattern. The question arises if the specificity is observed at the level of the 3-D-structure (conformational epitopes) and/or at the level of the primary structure (sequential epitopes). Using rabbit sera to horse cytochrome c, we show that discrimination against the host...
Cryopreservation of equine oocytes by 2-step freezing. Immature equine oocytes were frozen-thawed with ethylene glycol (EG), 1,2-propanediol (PD) or glycerol (GL) in PBS and cultured to assess the rate of in vitro maturation (Experiment 1). Compact-cumulus oocyte complexes were collected from slaughterhouse ovaries and equilibrated for 10 min in the freezing medium containing 10% (V/V) cryoprotectant and 0.1 M sucrose. The 0.25-ml straws, loaded with 10 to 30 oocytes, were seeded at -6 degrees C and cooled to -35 degrees C at 0.3 degrees C/min before being plunged into liquid nitrogen. The straws were thawed rapidly in a 37 degrees C waterbath for...
Energy metabolism, replicative ability, intracellular calcium concentration, and ionic channels of horse articular chondrocytes. Some aspects of the physiology of chondrocytes from horse articular cartilage were studied, since this animal model can be helpful in understanding arthritic processes. The replicative ability of articular chondrocytes, measured by the incorporation of [3H]thymidine, and their capacity of proteoglycan production, evaluated from the incorporation of [35S] sulfate, are very low. In addition, these cells do not differentiate in vitro as shown by the constant specific activity of alkaline phosphatase measured at different times in culture. Two types of potassium channels were identified by patch c...
Molecular cloning and expression of equine interleukin 2. We have cloned equine IL-2 cDNA in vitro using the polymerase chain reaction (PCR) and primers based on the human IL-2 sequence. The cloned product appears to contain the entire coding region for equine IL-2 based on homology with other known sequences. When expressed in COS cells, the recombinant product augmented the proliferative response of equine peripheral blood mononuclear cells to concanavalin A, however, it failed to support the continued proliferation of murine CTLL-2 cells. Specific substitutions in those regions associated with p55 and p75 binding appear to account for this species...
A comparison of the actions of platelet activating factor (PAF) antagonists WEB 2170 and WEB 2086 in the horse. The effects of the selective platelet activating factor (PAF) receptor antagonist WEB 2170 on PAF-induced responses in equine cells and tissues have been examined and compared with those of WEB 2086. In initial experiments WEB 2170 was shown to inhibit in vitro platelet aggregation in a dose-dependent, competitive reversible manner (pA2 = 7.21). Co-administration of the antagonists with either PAF or histamine also inhibited PAF, but not histamine, induced wheal formation and PAF-induced neutrophil accumulation in vivo in equine skin. Intravenous (i.v.) administration of both drugs at a dose o...
Effects of the 21-aminosteroid U-74389G on ischemia and reperfusion injury of the ascending colon in horses. Sixteen horses were allotted at random to 3 groups: vehicle only; low dosage (vehicle and 3 mg of U-74389G/kg of body weight); high dosage (vehicle and 10 mg of U-74389G/kg). These solutions were given prior to reperfusion. The ascending colon was subjected to 2 hours of ischemia followed by 2 hours of reperfusion. Before, during, and after ischemia, full-thickness colonic tissue biopsy specimens were obtained for measurement of malondealdehyde (MDA) concentration and myeloperoxidase activity and for morphologic evaluation. Although increases were not significant, MDA concentration and myelope...
Age-related characteristics of gastric squamous epithelial mucosa in foals. Specimens of grossly normal gastric stratified squamous epithelial mucosa adjacent to the margo plicatus on the right side and along the greater curvature were obtained from 7 foetuses, 10 term foals and 12 foals 2-35 days old. Gastric squamous epithelium from the foetuses changed markedly during gestation. At 150-270 days, the epithelium was 8-10 cells thick, with a single layer of basal cells. Epithelial cells were polyhedral and had abundant clear or slightly stained cytoplasm. In the 300-day foetus the basal layer was thicker, epithelial cells were polyhedral, and there was a flattened 1 c...
Developmental changes in the gonadotropin releasing hormone neuron of the female rabbit: effects of tamoxifen citrate and pregnant mare serum gonadotropin. Developmental changes in immunostained gonadotropin releasing hormone neurons were demonstrated in female rabbits assigned to the following treatment groups: (i) tamoxifen citrate, 10 mg.kg-1 x day-1, in sesame seed oil (vehicle) (n = 24) or (ii) vehicle alone (control, n = 24) for 108 days; and (iii) 50 IU of pregnant mare serum gonadotropin on postnatal days 22 and 25 (n = 24) or vehicle on nontreatment days. Treatments had no effect on the total number of immunostained cells, but there was a significant (p = 0.0160) developmental shift from cells with smooth processes to rough. Group compar...
Expression of an evolutionarily conserved function associated molecule on sheep, horse and cattle natural killer cells. Natural killer (NK) cells are large granular lymphocytes that lyse a wide variety of transformed and virally-infected target cells without prior exposure to antigen, and without restriction by major histocompatibility complex antigens. Although NK cells have been identified in a variety of mammalian species, how NK cells recognize antigen and trigger lysis is unknown. Recently, monoclonal antibodies made against NK-like cells from teleost fish were shown to react with NK cells from humans and rats, and to inhibit their cytolytic activity. The role of this apparently evolutionarily conserved fu...
Investigation of stimulus-secretion coupling in equine sweat gland epithelia using cell culture techniques. When sweat glands isolated from samples of horse skin were explanted and cultured under favourable conditions, they could exhibit cellular outgrowth. This growth could be maintained for 2-4 weeks and these primary cultures were then disaggregated and the resultant cell suspensions used to initiate epithelial cell lines. Secretion from intact equine sweat glands is regulated by beta 2-adrenoceptors and appears to be mediated by cyclic AMP, but there is evidence that calcium may also play a role. Adrenaline could increase the cyclic AMP content of the cultured cells and this response was mediate...
Volume-sensitive KCl co-transport and taurine fluxes in horse red blood cells. Potassium (using 86Rb+ as a tracer), amino acid and taurine fluxes were measured in horse red blood cells (RBCs). No volume-sensitive component of alanine and glycine transport was observed, and although volume-sensitive taurine fluxes were observed in most animals, their absolute magnitudes were small. K+ fluxes, however, were shown to be particularly volume sensitive; they were stimulated by cell swelling and inhibited by cell shrinkage. Sizeable fluxes were present at normal cell volumes. The volume-sensitive K+ flux was Cl- dependent and was abolished by Cl- replacement with methylsulphate...
Quantitative analysis of morphological modifications of day 6.5 horse embryos after cryopreservation: differential effects on inner cell mass and trophoblast cells. Sixteen embryos were recovered nonsurgically at day 6.5 after induced ovulation from Welsh pony mares and were evaluated for cellular changes that occur because of exposure to the cryoprotectant with or without the freeze and thaw process. Day 6.5 horse embryos were either (i) frozen and thawed using glycerol as cryoprotectant (n = 6), (ii) given only the glycerol treatment (n = 5), or (iii) washed in phosphate-buffered saline (PBS) the same number of times as in the glycerol treatment (n = 5). After treatments, embryos were incubated in Minimum Essential Medium (MEM), supplemented with BSA, g...
Pulsed magnetic fields improve osteoblast activity during the repair of an experimental osseous defect. The influence of pulsed low-frequency electromagnetic fields (PEMFs) on bone formation was investigated in studies of the healing process of transcortical holes, bored at the diaphyseal region of metacarpal bones of six adult horses, exposed for 30 days to PEMFs (28 G peak amplitude, 1.3 ms rise time, and 75 Hz repetition rate). A pair of Helmholtz coils, continuously powered by a pulse generator, was applied for 30 days to the left metacarpal bone, through which two holes, of equal diameter and depth, had been bored at the diaphyseal region. Two equal holes, bored at the same level in the rig...
Structural and functional characterization of rev-like transcripts of equine infectious anemia virus. Three cDNA clones representing structurally distinct transcripts were isolated from a cDNA library prepared from cells infected with equine infectious anemia virus (EIAV) by using a probe representing the S3 open reading frame, which is thought to encode Rev. One species, designated p2/2, contained four exons and was identical to a previously described polycistronic mRNA that encodes Tat. This transcript was predicted to also direct the synthesis of a truncated form of the transmembrane protein and a putative Rev protein whose N-terminal 29 amino acids, derived from env, are linked to S3 seque...
Independent modulation of horse airway smooth muscle by epithelium and prostanoids. The effects of epithelial removal and cyclooxygenase inhibition on contractions induced by exogenous acetylcholine (ACh) and electrical field stimulation (EFS) were evaluated in horse tracheal strips and bronchial rings. Epithelial removal potentiated the response to ACh but had no influence on the response to EFS. The effect of epithelial removal was not altered by pretreating the tissues with meclofenamate, a cyclooxygenase inhibitor. In trachealis strips, meclofenamate augmented contractions induced by EFS but not by ACh. In bronchial rings, meclofenamate augmented EFS-induced contraction t...
In vitro interaction between oviduct epithelial and equine sperm. Coculture of stallion sperm with monolayers of equine oviductal epithelial cells (OEC) was evaluated. Monolayers were obtained from frozen-thawed OEC. Live sperm attached to the OEC in vitro, whereas sperm killed by heat treatment or glutaraldehyde fixation did not. Sperm attached to OEC showed flagellar motion for 4 d in vitro, during which time they gradually became released. Scanning electron-micrographs showed an intimate association between the sperm and OEC. Incubation of sperm for 4 h with either control, heparinized or OEC-conditioned medium (Tyrode's albumin lactate phosphate) resulte...
Giant and binucleate trophoblast cells of mammals. The cellular origin, structure, and function of trophoblastic giant cells (GC) and binucleate cells (BNC) are reviewed. Mammals in which these cells have received the greatest attention include rodents, rabbits, and humans (GCs), and ruminants and equids (BNCs). In almost all cases these cells arise from the cytotrophoblast. All are large cells and contain either two diploid nuclei (BNCs), multiple nuclei (human placental bed GCs), or single nuclei with amplified DNA content (rodent and rabbit GCs). Giant and binucleate cells typically exhibit the capacity for migration or invasion, although t...
Cloning, expression and characterization of horse L-ferritin in Escherichia coli. Horse L-ferritin cDNA was cloned from horse liver, and the base sequence was determined. The L-ferritin was expressed using pTZ18U encoding lac promoter, and found to possess an additional 8-amino acid sequence at the N-terminus as compared with commercially obtained horse spleen (natural) ferritin. It was determined that there was Pro at position 94 in both the recombinant and natural L-ferritin, although it was previously reported that Leu was in this position in the natural species. Transmission electron microscopy showed that this recombinant ferritin formed a 24-mer shell.
Nucleation of the iron core occurs at the three-fold channels of horse spleen apoferritin: an EXAFS study on the native and chemically-modified protein. Extended X-ray absorbance fine structure measurements have been carried out on the initial Fe(III)-apoferritin complex at a Fe/subunit ratio of 2 in native and modified horse spleen apoferritin. Analysis of the data indicates that in the native protein the iron forms a protein-bound polynuclear cluster (Fe-Fe distance 3.4 A) with a first coordination sphere constituted by 5-6 low-Z atoms, e.g., nitrogen atoms, carboxylate-like ligands or oxo bridges between the iron atoms. Modification of Cys-126, a residue localized on the outer surface of the hydrophilic three-fold channels, with p-chloromer...
[Ganglioside GM3 from horse erythrocytes: structure and effect on cell proliferation]. An increase of the mouse fibroblast proliferation by ganglioside GM3 from equine erythrocytes is described. The structure of GM3 has been established on the basis of chemical methods, enzymatic degradation, GC-MS, as well as plasma desorption mass spectrometry and HPLC of 9-anthrylmethyl esters of gangliosides to characterize the long-chain base composition. The oligosaccharide moiety includes an N-glycolylneuraminic acid residue, whereas the main components of the lipid moiety are 20:1 sphingosine and 24:0 fatty acids.
Modulation of gonadotropin-releasing hormone-stimulated luteinizing hormone release in cultured male equine anterior pituitary cells by gonadal steroids. The objective of the present study was to determine whether the testicular steroids, i.e., testosterone (T), dihydrotestosterone (DHT), estradiol (E2), estrone (E1), and estrone sulfate (E1SO4), play a physiological role in regulating LH release in the male horse by direct actions at the anterior pituitary gland. Enzymatically dispersed anterior pituitary cells from stallions (n = 4) or geldings (n = 3) were cultured for 48 h in alpha-modified Eagle's medium containing 10% steroid-free horse medium. To determine the effects of the steroids on the LH response to GnRH, the cells were incubated f...
Reconstitution of horse heart myoglobin with hemins methylated at 6- or 7-positions: a circular dichroism study. The reconstitution kinetics of horse heart myoglobin, as met-cyano derivative, with two synthetic hemins in which the 6- or the 7-propionate is replaced by a methyl group, has been investigated by circular dichroism, in order to gain information on the heme re-orientation process following the heme insertion into the globin pocket. The results obtained confirm that the preferred heme orientation places the sole propionate into the position occupied by the 6-propionate in the crystal structure, supporting the importance of the salt bridge occurring between this propionate and the basic CD3 resi...
Comparison of cellular and molecular components of bronchoalveolar lavage fluid harvested from different segments of the equine lung. A comparison was made of the cellular and molecular components of bronchoalveolar lavage fluid (BALF) harvested from the left and right diaphragmatic lobes, the accessory lobe of the right lung and the apical lobe of the left lung, of seven control horses and six horses with symptomatic chronic obstructive pulmonary disease (COPD). Neither control nor symptomatic COPD affected horses showed significant regional differences in BALF recovery volumes, total and differential BALF cell counts, albumen adjusted total and absolute BALF cell counts, total and absolute pulmonary epithelial lining fluid...
Evaluation of urea and albumen as endogenous markers of dilution of equine bronchoalveolar lavage fluid. The urea and albumen dilution techniques for standardising the variable concentrations of pulmonary epithelial lining fluid (PELF) in bronchoalveolar lavage fluid (BALF) samples were evaluated in horses. Both techniques proved satisfactory and were of equal accuracy. Albumen adjusted BALF cell counts were significantly higher than PELF cell counts. BALF from normal horses contained, on average, 0.4 per cent PELF (range 0.1 to 1.0 per cent), as determined by the urea dilution technique.
Electron microscopical morphology of cytoplasmic granules from horse eosinophil leucocytes. The structure of specific granules from horse eosinophil leukocytes is still largely unknown. In this work, electron microscopical studies of horse eosinophils reveal that the large cytoplasmic granules contain an external membrane, a matrix of less density, and a dense (non crystalline) core. Round vacuolar inclusions of matrix materials were often observed within the cores. Horse eosinophil granules showed a considerable heterogeneity, and three morphological types could be identified according to structural features of the core and matrix.
