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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.
The ultrastructure of the cell types in the endocrine pancreas of the horse. The islets of Langerhans of the equine pancreas were examined with the electron microscope after immersion or perfusion fixation. Five cell types could be distinguished after fixation by either technique: 1. A-cells, situated at the center of the islets, 2. B-cells, containing mostly "pale granules" and constituting the principal cell type of the periphery of the islets, 3. D-cells, also located mainly at the periphery of the islets, 4. G-cells, found at the edge of the islets and in the exocrine pancreas, and 5. S-cells, (small granule cells), which are relatively few in number and occur only...
Ultrastructural observations on Ehrlichia equi organisms in equine granulocytes. The ultrastructure of the etiological agent of equine ehrlichiosis, Ehrlichia equi, was studied in equine peripheral leukocytes. The organisms occurred within membrane-lined cytoplasmic vacuoles of neutrophils and eosinophils. Ovoid, round, and rod-shaped profiles were observed. From 1 to 33 organisms were present in a thin-section profile of a cytoplasmic vacuole. Many cells contained multiple organism-containing vacuoles. The organisms had a cell wall and plasma membrane, and internally they consisted of electron-dense and lucid areas. A great variation in size was observed. The morphologica...
Light and electron microscopic investigation of equine synovial membrane. A comparison between healthy joints and joints with intraarticular fractures and osteochondrosis dissecans. Light and electron microscopic examination was made on equine synovial membrane from 23 healthy joints, nine joints with synovitis caused by intraarticular fracture and 10 joints with synovitis caused by osteochondrosis dissecans. Histologically as well as ultrastructurally the equine synovial membrane from healthy joints was of principally the same character as described in other species. Three types of synovial membrane — areolar, fibrous and adipose — and two types of lining cell were distinguished histologically. Ultrastructurally three types of lining cells were distinguished: A and ...
[Comparative study of tracheal epithelium of different mammals]. Tracheal epithelia of ten different mammals were investigated with the light and the electron microscope. Characteristic differences were found concerning the thickness of the epithelia, the length of the cilia, the density of the cells in the epithelia, the numerical distribution of the different cells and their ultrastructure. Special attention was paid to the morphology of the kinetosomes. Brush cells and chromaffin cells, which are sparsely distributed in the different tracheal epithelia, were discussed.
Ultrastructure of the synovial membrane. The normal synovial membrane as seen by electron microscopy is bordered by one to three layers of lining cells that include some with phagocytic function, others rich in endoplasmic reticulum for protein synthesis and additional cells with mixed properties. Lining cells with prominent Golgi apparatus probably produce the synovial hyaluronic acid. The synovial matrix contains collagen and mucopolysaccharide. It offers little barrier to diffusion of most materials. Superficial capillaries and venules are fenestrated and presumably allow rapid exchange of fluid and electrolytes. Deeper venules ha...
The evaluation of stallion semen in aspects of fertility control and its use for artificial insemination. Choice of the best methods for semen examination is dictated by the purpose of the examination, whether it be to assess the fertility of an individual stallion or to evaluate individual semen samples for routine purposes. In the author's experience of examining stallion semen, emphasis should be placed upon morphological examination, sperm cinematography and survival tests in vitro. Special problems concerning examination of frozen semen are discussed and the ultrastructure of spermatozoa frozen in the presence and absence of glycerol is described.
Fine structure of the gonads of the horse and its functional implications. Light and electron microscopic studies of the gonads of the fetal horse have shown that, in their hypertrophic condition which begins during the 3rd month, the interstitial cells contain large amounts of smooth endoplasmic reticulum, suggesting a secretory activity. Hydroxylating activity which was cytochrome P-450-dependent was observed in the fetal testis and may be involved in steroid biosynthesis.
Ultrastructural development of the equine placenta. Microcotyledons, which are a distinctive feature of the mature equine placenta, are fully formed by Day 150 of gestation. The fetal component of each microcotyledon is developed from several primary folds of trophoblast which become elaborately subdivided as gestation proceeds. These changes are reflected in the structure of the maternal crypts, which receive the fetal villi. Between Days 60 and 150 of gestation the maternal epithelium is greatly reduced in height. No such change occurs on the fetal side of the placenta, but between Days 100 and 250 a progressive indentation of the epithelium ...
Development of pituitary and adrenal glands in the fetal horse. The various cell types in the adult anterior pituitary may be distinguished at the ultrastructural level of the sizes of the secretory granules within the cytoplasm. In the fetal adenohypophysis, with the exception of prolactin-producing cells, all types may be identified after Day 100 of gestation. Morphological evidence suggests that they are producing and secreting trophic hormones. The three constituent layers of the adrenal cortex are also discernible by Day 100 of pregnancy. The cells of the zona glomerulosa have large numbers of darkly stained inclusions within the cytoplasm. The zona f...
Anatomy of the placental barrier in the mare. The study of the equine placenta, which began in Venice in 1598, has a long but discontinuous history. Early observations were purely morphological, but new techniques have stimulated a broader and more functional approach. Histological and ultrastructural observations at various stages of pregnancy have shown that the fetal side of the placenta comes to acquire certain features in common with the air-blood barrier of the mammalian lung. These changes may reflect the increasing O2 requirements of the fetus as gestation proceeds.
The ultrastructure of endometrial cups in pregnant mares. Electron microscopy and immunofluorescence techniques were used to study the various epithelial cells in the endometrial cups of ten pregnant mares, and in the uterine epithelium of one non-pregnant mare. Evidence was obtained which suggested that epithelial gland cells within the endometrial cups, as distinct from the hypertrophied decidual-like cells in the cup, may synthesize PMSG. The suggestion does not agree with the findings of other workers in the fetal origin (chorionic girdle cells) of this gonadotrophin.
The fine structure of the glycocalyx of equine spermatozoa: a high-resolution cytochemical study. Equine spermatozoa were obtained from ejaculates of young stallions. The seminal plasma was removed and the sperm pellets washed three times with 0-15 M-NaCl solution before final centrifugation at 4500 g for 15 min. The pellets were fixed in a mixture of 2-5% glutaraldehyde in 0-1 M-cacodylate buffer, pH 7-4, with 0-5% Alcian blue and post-fixed in 1% osmium tetroxide with 1% lanthanum nitrate; other samples were treated with ruthenium red. All samples were dehydrated in ascending concentrations of ethanol, embedded in araldite and thin sections examined in an electron microscope. Electron de...
An ultrastructural and histochemical study of the interstitial cells in the gonads of the fetal horse. Gonadal tissue obtained at about 50-day intervals from Days 60 to 300 of gestation was examined histologically, histochemically and in the electron microscope. The marked enlargement of the gonads (ovaries or testes) reached a peak around Day 250 and was caused by hypertrophy and hypoplasia of interstitial cells. These cells had all the ultrastructural characteristics of a steroid-secreting cell but delta5-3beta-hydroxysteroid dehydrogenase (3beta-HSD) was not detected at any stage of their development. There was no significant change in the ultrastructure of the interstitial cells between Day...
Leucocyte myosin and its location in the cell. The intracellular location of the binding site of antibody against purified myosin prepared from equine leucocytes was investigated in neutrophils and lymphocytes by electron microscopy using peroxidase-labelled antibody method. The myosin extracted from equine leucocytes could bind skeletal muscle F-actin and the formed complex showed the biophysical and biochemical properties and electron microscopic appearance of actomyosin. On immunodiffusion, the leucocyte myosin formed a single precipitin line with its antibody prepared in rabbits. The antibody also formed single precipitin lines with my...
[Arterial repair after mechanical injury by migrating fourth-stage larvae of Strongylus vulgaris in the horse (a light and electron microscopic study) (author’s transl)]. Migrating fourth-stage larvae of Strongylus vulgaris, a parasite of equines, damage the intima of the anterior mesenteric artery and its larger branches and induce thrombus formation on the injured sites. As the time of larval passage through each of these branches has been exactly determined in earlier experiments, the aim of the present studies is to contribute to a more complete understanding of repair mechanisms in the process of time after thrombotic vascular injuries. Methods: five foals were separated individually to specially cleaned stables and given anthelmintic treatment till the ag...
A scanning electron microscopic study of platelets of certain animal species. Comparative morphology of platelets of the dog, cat, cow, horse, sheep, and goat was studied with the scanning electron microscope and was found generally similar. Most of the platelets were slightly biconvex of flat with relatively smooth surface and even contour. Some of these platelets had few short marginal filaments, oriny protuberances on the surface. A small number of platelets exhibited surface irregularity and few long pseudopods which were thought to result from platelet activation during the processing of blood. The number os such irregular platelets increased in stored blood and in...
Giant cell tumor of soft parts. A report of an equine and a feline case. Masses removed from the superficial fascia of the jugular groove of a 12-year-old Arabian mare and from the femoral canal of a 7 1/2-year-old female cat appeared to be counterparts of the human malignant giant cell tumor of soft parts, even recapitulating the clinical behavior of the respective subgroups. Histologically, both neoplasms contained the characteristic features of the malignant giant cell tumor of soft parts: large multinucleate giant cells, pleomorphic mononuclear giant cells, histiocytes, fibroblasts and fibrocytes that were sometimes sarcomatous, and foci of hemorrhage and necro...
Acute rhabdomyolysis (“tying-up”) in standardbred horses. A morphological and biochemical study. LINDHOLM, A., H.-E. JOHANSSON & P. KJÆRSGAARD: Acute rhabdomyolysis (“tying-up”) in standardbred horses. A morphological and biochemical study. Acta vet. scand. 1974, 15, 325–339. — Morphological, biochemical and histochemical changes were studied in muscle needle biopsy specimens (gluteus medius) from 59 standardbred trotters with acute clinical symptoms of the “tying-up” disease. All horses had increased levels of serum enzymes SGOT and SCPK. The biopsy specimens were taken at various intervals after onset of clinical symptoms (1–4 hrs., 18–24 hrs. and 2–20 days). Ry light...
Tyzzer’s disease in a foal. Light- and electron-microscopic observations. Tyzzer's disease was diagnosed in a 17-day-old foa l after the demonstra tion
of mu ltip le foci of hepat ic necro sis and organisms morphologically compatible with
Bacillus piliformis in hepa tocytes at the margins of the necrotic foci. Th e bac illi were
300 to 500 nm in diameter with occa sional giant bacilli 1000 nm in d iameter. Ma ny intranuclear organisms were seen, and a n a pparent sequence of nuclear penetration by these
organisms was demonstrated . There was hem orrhage in the hear t a nd inflamma tory
cha nges in the mesenteric lymph node . Enteritis was no t pre sent in the j...
