Topic:Ultrastructure
Ultrastructure refers to the detailed architecture of biological cells as observed through electron microscopy. In horses, the study of cellular ultrastructure provides insights into the organization and function of various tissues and organs at a microscopic level. This includes the examination of cellular components such as mitochondria, endoplasmic reticulum, and lysosomes. Understanding the ultrastructure of equine cells aids in identifying cellular changes associated with disease processes, developmental stages, and physiological adaptations. This page compiles peer-reviewed research studies and scholarly articles that explore the ultrastructural characteristics of equine cells and tissues, contributing to a deeper understanding of equine biology and pathology.
Equine laryngeal hemiplegia. Part II. An electron microscopic study of peripheral nerves. The recurrent laryngeal nerves were examined by electron microscopy in five control, four subclinical and four clinical laryngeal hemiplegic horses. In addition, the peroneal nerve was examined in two horses in the latter group. The distally distributed loss of large myelinated fibres in the left recurrent laryngeal nerve seen by light microscopy was confirmed. In addition, active axonal pathology was found to be more evident than indicated by light microscopic investigations. The onion bulb formations observed indicated the repetitive nature of the damaging influence to nerve fibres. Although...
Ultrastructural study of the equine cecum during onset of laminitis. The morphologic and pathologic changes which occurred within the cecal mucosa of 4 horses during the onset of laminitis were determined from cecal biopsy materials obtained via a cecal fistula; the laminitis was induced with carbohydrate overload. The cecal epithelial mucosa specimens were obtained at 0 (base line), 24, 32, 48, and 72 hours after horses were given carbohydrate overload, and these were fixed and subsequently photographed. Changes in the cecal epithelium were examined by transmission electron and scanning electron microscopies. These histopathologic changes indicated that the mu...
Pi granules and related intracytoplasmic inclusions in equine Schwann cells. Suchwann cells from a variety of nerves in two adult horses and one adult pony contained perinuclear intracytoplasmic inclusion complexes consisting of lipid droplets, variably electron-dense rounded to elongated bodies and rod-shaped multilamellar structures. The latter were characteristic of pi granules of Reich. There were no significant axonal or myelin alterations associated with these inclusions. It was concluded that the inclusions are a component of normal equine Schwann cells.
Morphogenesis of Berne virus (proposed family Toroviridae). In equine dermis cells infected with Berne virus particles were first detected 10 h after infection. Virions were encountered in all parts of the Golgi system and, infrequently, in the rough endoplasmic reticulum. A unique form of budding of preassembled rigid tubular nucleocapsids was demonstrated. Masses of tubular nucleocapsids of a lesser diameter and electron density were prominent in the cytoplasm and the nucleus of infected cells. Within the Golgi system and cytoplasmic cisternae virions appeared as straight or slightly curved rods. Extremely long, aberrant virions (250 nm) were occasio...
The relationship between lipofuscin and neuromelanin in some sites of the nervous system of the horse. Histochemical and cytochemical features of neuronal pigment in the spinal cord, and in the sympathetic and spinal ganglia of the adult horse have been studied. Light and electron microscopical observations revealed that lipofuscin pigment is present in the spinal ganglia and in the spinal cord, whereas in the sympathetic ganglia both lipofuscin and neuromelanin are present. The ultrastructural studies showed that lipofuscin granules exhibited a triphasic organization consisting of a matrix, a system of lamellae and one or more lipid vacuoles. Neuromelanin granules have structural features in c...
Comparative scanning electron-microscopic study of the lingual papillae in two species of domestic mammals (Equus caballus and Bos taurus). 1. Gustatory Papillae. The morphological characteristics of bovine and equine gustatory lingual papillae are compared by scanning electron microscopy. The fungiform papillae in the cow have a shape that corresponds to their name, while in the horse, they almost do not emerge from the surface of the tongue. These papillae show taste pores in both species. The vallate papillae, four times larger in the horse than in the cow, show a complex organization of papillae and secondary grooves in the horse. In the cow, they occur single and are surrounded by a thick annular pad of lingual mucosa. Taste pores have been observe...
Gas chromatography-mass spectrometry of androgens in equine ovarian follicles at ultrastructurally defined stages of development. Identification of 19-nortestosterone in follicular fluid. Follicular fluid was obtained from equine follicles at different stages of development as determined by ultrastructural study. Gas chromatography-mass spectrometry associated with stable isotope dilution permitted the demonstration of high levels of 4-estrene-3,7-dione and 17 beta-hydroxy-4-estren-3-one, 17 beta-hydroxy-4-estren-3-one levels often being about 10 times higher than those of testosterone. These findings suggest that in the mare ovary, an aromatizing pathway may proceed using these 19-norsteroids as intermediates. As a consequence of this high level of 19-norsteroids, testosterone...
Ultrastructural study of ehrlichial organisms in the large colons of ponies infected with Potomac horse fever. Potomac horse fever is characterized by fever, anorexia, leukopenia, profuse watery diarrhea, dehydration, and high mortality. An ultrastructural investigation was made to search for any unusual microorganisms in the digestive system, lymphatic organs, and blood cells of ponies that had developed clinical signs after transfusion with whole blood from horses naturally infected with Potomac horse fever. A consistent finding was the presence of rickettsial organisms in the wall of the intestinal tract of these ponies. The organisms were found mostly in the wall of the large colon, but fewer organ...
Ultrastructural variations in the sweat glands of anhidrotic horses. The ultrastructure of sweat glands from the skin of free sweating horses was compared with that of glands from anhidrotic cases. Evidence of atrophied and abnormal sweat glands in the anhidrotic horses indicates that the condition involves progressive failure of the glandular mechanism of sweat production.
Case of angiosarcoma of the nasal passage of the horse–ultrastructure and differential diagnosis from progressive haematoma. An angiosarcoma involving the right frontal and maxillary sinuses in a nine-year-old Thoroughbred mare was studied post mortem by light and electron microscopy. Important diagnostic features included malignant endothelial cells lining ill-defined vascular spaces, supported by other vasoformative elements. Rhabdomyoblasts were also found. The tumour is apparently rarely seen in the nasal passages of the horse.
Intimal asteroid bodies in horses: light and electron microscopic observations. The morphology of asteroid bodies in equine arteries is demonstrated by light microscopy as well as by scanning and transmission electron microscopy combined with chemical analysis. Asteroid bodies first occur in horses at four weeks of age in all investigated tissues except the esophagus and always are located in the subendothelial space. The number, shape, ultrastructure and chemical composition of asteroid bodies differ markedly--depending on the age of the horse. Asteroid bodies are round and smooth in foals, but are shaped irregularly and have several projections and marked stratified cal...
Microtubular mass defect of spermatozoa in the stallion. A microtubular mass (MM) defect was found in the spermatozoa of 7 Standardbred stallions; 3 stallions were sons of the same sire. Two of these 3 stallions and 2 other stallions (for a total of 4 out of the 7 stallions) were considered subfertile when the defect was first observed. Fertility improved with time, either during the first breeding season or when a given stallion was used less frequently; however, the MM defect persisted, consisting of tortuous arrays of small abnormal microtubules visible only by transmission electron microscopy. The MM probably contained the protein tubulin as ind...
Morphology of three strains of contagious equine metritis organism. Examination of recently isolated cultures of three strains of Contagious Equine Metritis Organism grown on specially formulated, serum-free, clear typing medium revealed the presence of numerous colonial opacity variants. These colonies were prepared by a number of fixation and staining techniques and examined by scanning and transmission electron microscopy. Opaque and transparent phenotypes produced copious amounts of extracellular material compared with intermediate-opacity phenotypes which produced little or none. Also unique to intermediate colonies were numerous thin intercellular strand...
Estrogen metabolites in equine ovarian follicles: gas chromatographic-mass spectrometric determinations in relation to follicular ultrastructure and progestin content. Equine follicular fluid was aspirated at various developmental stages (viable, preovulatory and atretic) determined by ultrastructural study. Estrogens and progestins were analyzed by gas chromatography-mass spectrometry associated with stable isotope dilution. Progesterone and 17-hydroxyprogesterone were the principal progestins of the preovulatory and viable follicles. Among the catechol estrogens, 2-hydroxy-estradiol was particularly abundant in the preovulatory follicle and its definitive identification was made by the scan of a full mass spectrum.
Flunixin meglumine attenuation of endotoxin-induced damage to the cardiopulmonary vascular endothelium of the pony. Endotoxic shock was induced in 5 ponies by intraperitoneal injections of 20, 40, 60, 80, and 80 micrograms of Escherichia coli endotoxin (LPS)/kg of body weight at 0, 6, 12, 18, and 24 hours, respectively. At 24 hours, the ponies also were given 20 micrograms of LPS/kg via catheter in the left ventricle of the heart. A 2nd group of 4 ponies was given 1.1 mg of flunixin meglumine (FM)/kg, IV, at 6, 12, 18, and 24 hours just before the corresponding LPS injection. Two hours after the 24-hour LPS injection, the ponies in both groups were anesthetized, the lungs were perfused with fixative, and po...
Fine structure of the epithelia of the vomeronasal organ of horse and cattle. A comparative study. The vomeronasal organ of both horses and cattle is a tubular structure situated bilaterally at the base of the nasal septum. In frontal plane the shape of its lumen is semilunar to crescent. The sensory epithelium lining the medial wall of the lumen contains receptor, supporting and basal cells with some surface modifications in both species. In the horse, a structure similar to a microprocess was observed among the microvilli of receptor cells. In cattle, a large mass of the cytoplasm of the receptor cell occasionally protrudes to form a bleb-like structure. The supranuclear cytoplasm of the ...
Topography and enterocyte morphology of the small bowel mucosal surface in equine granulomatous enteritis. The jejunal mucosa of 4 cases of equine granulomatous enteritis and 2 control horses was investigated by light microscopy and by scanning and transmission electron microscopy. Attention was focused upon changes in mucosal topography and enterocyte morphology in the inflamed mucosa. Structural changes ranged in severity from only a slight thickening and shortening of villi to the appearance of a virtually flat mucosa, upon which crypts opened directly or through shallow cavities encircled by collars of epithelial cells. Between these extremes, the mucosa showed a variety of patterns, all charac...
[Attachment of horse cecum Ciliata to plant fragments. Degradation of chloroplasts. Attachment of bacteria to cecal Ciliata]. Cecum microfauna association with different plant tissues was examined by scanning and transmission electron microscopy. The ciliates were attached to the damaged areas of the leaves and their highest concentrations were found on the epidermis and mesophyll tissues. The degradation of plant tissue was due to protozoal ingestion of the plant fragments. The morphology of ingested envacuolized chloroplasts changed rapidly, showing different stages of digestion inside the ciliate endoplasm. Intact chloroplasts were rarely observed but the grana of fragmented thylakoid membranes was often seen. The...
Some unusual features of mesangioproliferative glomerulonephritis in horses. Seven horses ranging from three to 15 years of age had nephrotic syndrome; at necropsy, renal tissue of all seven horses had the morphologic lesions of mesangioproliferative glomerulonephritis (membranoproliferative glomerulonephritis). Homogeneous eosinophilic material which filled the glomerular capillary lumina was found in five horses. Ultrastructurally, this material primarily consisted of electron-dense deposits with a fibrillar pattern in five horses and in one horse, rhomboid crystalline deposits which resembled deposits seen in human cryoglobulinemia. The association of mesangioprolif...
Disposition of the manchette in the normal equine spermatid. Bielanski and Kaczmarski (1979) reported the presence of microtubules in the neck region of mature stallion spermatozoa. It was hypothesized that these microtubules are derived from the manchette (a microtubular organelle present during spermiogenesis). In order to test this hypothesis, testes from 15 mature stallions were collected, perfused with 2% phosphate-buffered glutaraldehyde, and prepared for transmission electron microscopy. Spermatozoa from the caudae epididymides of each stallion were prepared in a similar manner. Spermiogenesis was observed in general, and the presence of a microt...
Functional and ultrastructural evaluation of neutrophils from foals and lactating and nonlactating mares. Neutrophils from 4 pony foals, 3 lactating pony mares, and 3 nonlactating mares were evaluated ultrastructurally and by in vitro function tests. Neutrophils from foals had significantly (P = 0.05) less random migration than neutrophils from mares; values in tests for iodination and Staphylococcus aureus ingestion were also lower with foal neutrophils. Neutrophils from lactating mares had lower responses to iodination, antibody-dependent cell-mediated cytotoxicity, and random migration tests than did neutrophils from nonlactating mares. Ultrastructurally, granule concentration did not differ si...
The comparative pathology of equine cutaneous phycomycosis. Pythiosis (204 cases, 77%), basidiobolomycosis (48 cases, 18%), and conidiobolomycosis (14 cases, 5%) were diagnosed morphologically from 266 horses with phycomycosis. All lesions were cutaneous ulcerative granulomas and three horses with pythiosis had metastatic lesions in regional lymph nodes. Lesions of pythiosis contained characteristic yellow, coral-like coagula and had a fibrotic surface containing sinus tract openings. Basidiobolomycosis was characterized by infrequent small yellow coagula and a yellow line of fungal invasion beneath an edematous surface. Lesions of conidiobolomycosis h...
Dermal collagen degradation and phagocytosis. Occurrence in a horse with hyperextensible fragile skin. A 2-year-old female horse had large areas of hyperextensible, fragile skin that were interspersed with areas of normal skin. Affected skin tore easily and contained reduced amounts of dermal collagen. Collagen fibers were fragmented and disorganized, and in trichrome-stained sections, many fibers had abnormal red-stained centers. Electron microscopy showed that many collagen fibers had discrete foci of degradation in which the fibrils were fragmented, loosely packed, and widely separated by granular material. Collagen fibril fragments were present in secondary lysosomes in dermal fibroblasts, ...
Ultrastructural comparison of Oncovirinae (type C), Spumavirinae, and Lentivirinae: three subfamilies of Retroviridae found in farm animals. The successive steps of maturation of seven retroviruses from five species of farm animals and one retrovirus from a mouse were compared in cell cultures. The viruses included three type C oncoviruses, one spumavirus, and three lentiviruses. Although members of the 3 subfamilies shared some gross morphologic features such as budding on plasma membranes, core, and surface projections, differences were noted in the ultrastructural detail of these features. Type C oncoviruses did not show any structural differentiation in identifiable form in the cytoplasm as opposed to characteristic features ob...
Cholesteric organization of DNA in the stallion sperm head. The fine structure of chromatin in sperm heads was investigated by different microscopic techniques: in vivo examinations in the polarizing microscope, thin sections and freeze-fracture replicas observed by transmission electron microscopy. The freeze-fractured chromatin appears to be formed of superimposed lamellae, each one 330 A thick. These lamellae are parallel to the flattening plane of the sperm head. This situation was already described in other mammal spermatozoa and in particular in the bull and the rabbit. This work presents a new interpretation of this lamellated aspect. The chroma...
C-cell tumours of the thyroid in the horse. The clinical and pathological aspects of two cases of C-cell (parafollicular cell) tumours of the thyroid are described. Both the horse and the pony presented with a paralaryngeal mass and a history of constant gulping. Ultrastructural examination of the tumours demonstrated that they were composed of C-cells containing typical, membrane-bound secretory granules. The pony is alive and well three years after surgery and the horse has raced successfully following removal of the tumour.