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.
Staszyk C, Gasse H.The periodontal ligament (PDL) of the hypsodont cheek teeth of the horse meets specific requirements of tooth support: (1) to fix the tooth; (2) to withstand pressure and tension during the laterolateral mastication movement; (3) to restore the original tooth position. These requirements are assumed to be met by the periodontal collagen fiber apparatus and by the vascular system. Distinct fibro-vascular arrangements are described here in order to reveal the structural prerequisites for these distinct functions. Methods: Specimens from nine horses were processed for (1) collagen labeling with f...
Döpke C, Gröne A, von Borstel M, von Oppen T, Boéve MH, Baumgärtner W.A 17-year-old horse developed severe proptosis of the left eye over a period of 1.5 years. At post-mortem examination a neoplasm was found involving the left ethmoid bone, left maxillary sinus, left orbit, left superior turbinate, and the left eye. Tumour cells were arranged in nests separated by a fine fibrovascular stroma. Immunohistochemically, the tumour cells were labelled by antibodies against neurofilament protein, synaptophysin, glial fibrillary acidic protein and S-100 protein antigen, but were negative for chromogranin A, cytokeratin and desmin. Electronmicroscopically, the cells sho...
Watanabe T, Hosaka Y, Yamamoto E, Ueda H, Tangkawattana P, Takehana K.The Golgi tendon organ (GTO) is an encapsulated fusiform mechanoreceptor siding in the musculo-tendinous junction of many animal species. Inhibitory function of afferent nerve fibers distributed from nearby motor units, the organ responds to active tension exerted onto the muscle. The morphological features of the equine GTO have not yet been elucidated. Additionally, there is some controversy regarding to the existence of the GTO in the equine superficial digital flexor tendon (SDFT). Therefore, immunohistochemistry and immunoelectron microscopy using alcian blue (pH 2.5) staining and the sil...
Locke M.Techniques for staining (silver, osmium, metal sulfides, ink) and microphotography (epi-illumination) of polished bone surfaces have been developed to visualize the three-dimensional structure of the shafts of mammalian long bones. Bone is a two-compartment system with capillaries and some kinds of connective tissue in one compartment separated from fibers of bone collagen, often forming lamellae, in the other. Laminar bone consists of stacks of lamellae separated by vascular spaces containing capillary network sheets. It is deposited at the periosteal and endosteal surfaces. Osteonic bone, we...
Al-Bagdadi FK, Eilts BE, Richardson GF.Scanning electron microscopy (SEM) was used to study the endometrium of nine 1-year-old thoroughbred mares after twice intrauterine infusions of gentamicin, on 2 consecutive days. Five mares were infused on 2 consecutive days with 40 ml gentamicin (50 mg/ml) mixed with 80 ml of normal saline. Four mares served as controls and were infused with 120 ml of saline on 2 consecutive days. Endometrial biopsies were obtained from all mares 3 days after the second intrauterine infusion. Each biopsy was processed for SEM by standard methods. The endometrial epithelium of the gentamicin-infused mares had...
White SD, Affolter VK, Bannasch DL, Schultheiss PC, Hamar DW, Chapman PL, Naydan D, Spier SJ, Rosychuk RA, Rees C, Veneklasen GO, Martin A, Bevier D....Data on fifty horses with hereditary equine regional dermal asthenia (HERDA; "hyperelastosis cutis") were collected on clinical, histopathological, ultrastructural and immunohistological findings. All horses were Quarter horses or of Quarter horse ancestry. Pedigree evaluation strongly supported an autosomal recessive mode of inheritance. The most common lesions were seromas/haematomas, open wounds, sloughing skin, and loose, easily tented skin that did not return to its initial position. Definitive diagnosis could not be made via histopathology, although the presence of tightly grouped thin a...
Ueki H, Kowatari Y, Oyamada T, Oikawa M, Yoshikawa H.Thyroid tumours occur in older horses, and most such tumours have been considered to be of follicular epithelial origin. However, their immunohistochemical characterization has not been investigated. The purpose of this study was to confirm a suspicion that most of these tumours are in fact parafollicular cell (C cell)-derived adenomas, and to evaluate their pathogenesis and functional state. Thyroid glands from 38 horses aged 10-29 years were evaluated, all tissue samples being examined histologically, immunohistochemically and ultrastructurally. Nodular tumour masses were found in the thyroi...
Ghaoui Rel-H, Thomson PC, Evans G, Maxwell WM.Membrane vesicles, separated by differential centrifugation from the seminal plasma, were detected in the sperm-rich ejaculate fractions of four boars and three stallions, and in the whole ejaculates of seven rams. The volume and percentage of vesicles, determined by a stereological technique, were higher in the sperm-rich than in the post-sperm-rich fractions of the boar and stallion ejaculates, and no vesicles were detected in the pre sperm-rich fractions. Vesicles were examined by transmission electron microscopy (TEM) and scanning electron microscopy (SEM). For boar, stallion and ram semen...
French KR, Pollitt CC.Light microscopical studies show that the key lesion of laminitis is separation at the hoof lamellar dermal-epidermal interface. More precise knowledge of the damage occurring in the lamellar basement membrane zone may result if laminitis affected tissue is examined with the transmission electron microscope. This could lead to better understanding of the pathogenesis of lesions and the means of treatment or prevention. Objective: To investigate the ultrastructure of acute laminitis as disease of greater severity is induced by increasing oligofructose (OF) dosage. Methods: Three pairs of normal...
French KR, Pollitt CC.Acute laminitis is characterised by hoof lamellar dermal-epidermal separation at the basement membrane (BM) zone. Hoof lamellar explants cultured in vitro can also be made to separate at the basement membrane zone and investigating how this occurs may give insight into the poorly understood pathophysiology of laminitis. Objective: To investigate why glucose deprivation and metalloproteinase (MMP) activation in cultured lamellar explants leads to dermo-epidermal separation. Methods: Explants, cultured without glucose or with the MMP activator p-amino-phenol-mercuric acetate (APMA), were subject...
Angele P, Abke J, Kujat R, Faltermeier H, Schumann D, Nerlich M, Kinner B, Englert C, Ruszczak Z, Mehrl R, Mueller R.Collagen-based scaffolds are appealing products for the repair of cartilage defects using tissue engineering strategies. The present study investigated the species-related differences of collagen scaffolds with and without 1-ethyl-3-(3-dimethyl aminopropyl) carbodiimide (EDC)/N-hydroxysuccinimide (NHS)-crosslinking. Resistance against collagenase digestion, swelling ratio, amino acid sequence, shrinkage temperature, ultrastructural matrix morphology, crosslinking density and stress-strain characteristics were determined to evaluate the physico-chemical properties of equine- and bovine-collagen...
Bragulla H, Hirschberg RM.Accessory organs of the integument are locally modified parts of the potentially feather-bearing skin in birds (e.g., the rhamphotheca, claws, or scales), and of the potentially hairy skin in mammals (e.g., the rhinarium, nails, claws, or hooves). These special parts of the integument are characterised by a modified structure of their epidermal, dermal and subcutaneous layers. The developmental processes of these various integumentary structures in birds and mammals show both similarities and differences. For example, the development of the specialised epidermal structures of both feathers and...
Bae SE, Watson ED.It has been reported that oxytocin is produced not only in the hypothalamus and posterior pituitary but also in outside the classical hypothalamo-neurohypophyseal axis such as the ovary, testis, placenta and in some nonreproductive sites. In the mare, oxytocin-mRNA has been identified in the endometrium, and oxytocin and its neurophysin have been identified in the uterus. In the present study, oxytocin was localised in the endometrium of the mare at the light microscopic and ultrastructural level by immunostaining and immunogold labelling of endometrial biopsy specimens collected during estrus...
Dongus H, Beelitz P, Schöl H.The female reproductive system of Thelazia lacrymalis (Nematoda: Thelaziidae) was investigated by light and scanning electron microscopy (SEM) with regard to the developmental stages and the stage deposited by the gravid nematode. Female T. lacrymalis have a didelphic and opisthodelphic type of reproductive system with paired ovaries, oviducts and uteri and a single vagina and vulva. Round and spindle-shaped primary oocytes are documented within the ovaries and oviducts, respectively. The distal part of each uterus provides a fertilization chamber filled with spermatozoa, followed by a sphinct...
Oikawa M, Ohishi H, Katayama Y, Kushiro A, Yoshikawa H, Yoshikawa T.A mass developed in the mandibular gingiva of a thoroughbred racehorse. When the horse could no longer eat unassisted, it was killed and immediately autopsied. Macroscopically, the mandible exhibited extensive osteolysis, with only a small amount of bone remaining around the tooth roots. The cut surface of the mass around the mandible consisted of neoplastic medullary tissue, in which osteogenesis was observed. The medullary tissue was composed of pleomorphic medium-sized to large cells, interlaced by collagen bundles. These cells had large, pale, round or ovoid, sometimes cleaved nuclei, with...
Bork S, Yokoyama N, Matsuo T, Claveria FG, Fujisaki K, Igarashi I.We evaluated the growth inhibitory effect of triclosan, which has recently been reported to inhibit the growth of Plasmodium species and Toxoplasma gondii, on bovine and equine Babesia parasites in in vitro cultures The growth of Babesia bovis and B. bigemina was significantly inhibited in the presence of 100 microg/ml of triclosan, while B. caballi and B. equi were susceptible to as low as 50 microg/ml. Babesia bigemina and B. caballi were completely cleared as early as on the first and second day of the treatment, respectively. These parasites did not exhibit any growth in the subsequent fiv...
Grulke S, Deby-Dupont G, Cassart D, Gangl M, Caudron I, Lamy M, Serteyn D.In cases of equine acute abdominal disease, where pancreatic damage is suspected, pancreatic damage can be assessed by measuring increased trypsin activity in the plasma of horses suffering intestinal obstruction and severe shock. The pancreas is particularly vulnerable to splanchnic hypoperfusion because it is a highly active tissue. In this study, 10 horses undergoing abdominal surgery for intestinal obstruction were assayed for trypsin activity on admission and, because of extensive intestinal lesions that were not amenable to surgery, euthanasia was selected; the pancreas was removed befor...
Kohama M, Nio J, Hashimoto Y, Iwanaga T.The intimal lining cells of the synovium in joints have been studied morphologically and histochemically and shown to consist of macrophagic cells (type A) and fibroblast-like cells (type B). It is believed that the structure of the synovium in the tendon sheath is similar to that in the joint, but there have been only a few morphological studies of the tendon sheath. The present study revealed the cellular architecture of synovium in the tendon sheath of horses by histochemistry and scanning electron microscopy (SEM). Like the joint, the inner surface of the tendon sheath was covered with a c...
Patrick DJ, Kiupel M, Gerber V, Carr EA.A 2-year-old female Miniature Horse that presented with a history of progressive weight loss, depression, and diarrhea was diagnosed at necropsy with a highly malignant abdominal neoplasm involving the left ovary, kidneys, adrenal glands, intestines, and various abdominal and thoracic lymph nodes. Microscopic examination of these masses revealed large pleomorphic cells that stained positive for vimentin and inhibin and negative for epithelial membrane antigen and placental alkaline phosphatase. Ultrastructural examination of the cells revealed a high nucleocytoplasmic ratio and indented euchro...
Lieto LD, Swerczek TW, Cothran EG.Necropsy of two American Saddlebred fillies diagnosed with epitheliogenesis imperfecta (EI) revealed missing patches of epithelium of the skin and oral mucosa as well as dental abnormalities. Examination of the digestive tract did not reveal signs of pyloric atresia in either foal. Histopathologic examination revealed separation of the epidermis from the dermis. In both foals a division within the lamina lucida of the basal lamina was observed by transmission electron microscopy. In comparison with an age-specific control, the ultrastructure of intact skin from the EI-affected foals showed abn...
Budras KD, Schiel C, Mülling CK, Patan B.The preparation of hard tissues such as the equine hoof horn for electron microscopic examination is very difficult. In particular the penetration of fixatives and chemicals used during fixation and embedding is a problem. The objective of this study was to find and implement an alternative method enabling the preparation of high-quality thin sections of hoof horn and other hard tissue, which maintains the hard tissue ultrastructure and can be used for immuno-labeling. Compared to commonly used fixation and embedding techniques, the preparation of thin sections from untreated material method s...
Kurotaki T, Narayama K, Arai Y, Arai S, Oyamada T, Yoshikawa H, Yoshikawa T.Histopathologic and electron microscopic observations were given on Langerhans cells (LCs) within the follicular epithelium (FE) and intradermal sweat duct (ISD) of equine "Kasen". By light microscopy, LCs were present in the greatest numbers within the FE and ISD than within the epidermal layer and the normal skin, with an occasional formation of several aggregated foci. By electron microscopy, LCs within the FE and ISD widely extended their dendritic processes between the keratinocytes and contained Birbeck granules (Bgs), mitochondria, rough endoplasmic reticula and ribosomes in the cytopla...
Germanà A, Cassata R, Cristarella S, Scirpo A, Muglia U.The three-dimensional architecture of the myosalpinx in the mare was investigated by means of scanning electron microscopy (SEM) after removal of interstitial connective tissue with NaOH digestion. In the extramural portion of the tubo-uterine junction (TUJ), isthmus, and ampulla, the myosalpinx architecture is represented by a unique muscular structure which runs from the mesosalpinx to the base of the inner mucous folds. This unique muscular structure consists mainly of bundles of muscular fibers independent of one another, which show a multiple spatial arrangement and form a complex network...
Muylle S, Simoens P, Lauwers H.The objective of this study was to examine the diameter, extent, orientation and contents of dentinal tubules in order to validate the hypothesis of pigment penetration into the dental star of equine incisival occlusal surfaces. The time of appearance and the configuration of the dental star on the incisival occlusal surface are macroscopically visible features that, along with other more reliable parameters, are used for the determination of horses' age. Although dental stars are an integral part of the equine incisor occlusive surface, the exact nature and microstructure of the dental star a...
Klomkleaw W, Kasashima Y, Fuller GA, Kobayashi A, Yoshihara T, Oikawa MA, Izumisawa Y, Yamaguchi M.An anatomical study of horse lumbrical muscle (Lm) was carried out by light and electron microscopy in combination with immunochemical and cytochemical methods. Paraffin sections were subjected to haematoxylin and eosin (H & E) and Masson's trichrome staining for morphometric analysis. Paraffin sections were also used for immunostaining by anti-PGP 9.5 for reaction with nerve-protein associated-structures, anti-heat-shock protein 70 (hsp 70) for detection of gene expression changes, anti-fast myosin for the determination of muscle fibre types, and for detection of apoptotic gene expression...
Mobarak MS, Ryan MF.The ultrastructure of the dorsal oesophageal gland ampulla and its relationship with the oesophagus, oesophageal ultrastructure, and control mechanisms in oesophageal activity were studied. Terminal ducts of the sub-ventral glands open through the oesophageal crown at the base of the buccal cavity. The terminal duct of the dorsal oesophageal gland running through the dorsal gutter opens to the exterior at the rim 'groove' of the buccal capsule. The posterior oesophageal region is clavate and the cuticle of the lumen folds to form outlet valves, 'valvulae'. An inconspicuous oesophago-intestinal...
Al-Zi'abi MO, Fraser HM, Watson ED.In mares, little information is available on the type of cell death that occurs during natural and induced luteal regression. Corpora lutea were collected from mares in the early luteal phase, days 3-4 (n = 4); mid-luteal phase, day 10 (n = 5); early regression, day 14 (n = 4); late regression, day 17 (n = 4); and 12 and 36 h (n = 3 per group) after PGF2alpha administration on day 10. Histological and ultrastructural sections were examined and TUNEL was used to detect DNA fragmentation. In early luteal regression, there were more pyknotic luteal cells and extracellular round dense bodies compa...
Del Piero F, Summers BA, Cummings JF, Mandelli G, Blomme EA.Eleven gastrointestinal neoplasms from 10 aged horses and 1 pony were examined grossly, his tologically, immunohistochemically, and (in two cases) ultrastructurally. Clinical signs were associated with two neoplasms, and the other nine tumors were incidental findings at laparotomy or necropsy. The neoplasms were solitary (9/11) or multifocal (2/11), well demarcated, serosal or mural masses of stomach (1), jejunum (1), ileum (3), cecum (5), and/or colon (2). Microscopic examination revealed discrete spindle cells arranged in compact patterns with fascicles and whorls or cribriform pattern with ...
Wooding FB, Morgan G, Fowden AL, Allen WR.Equine chorionic gonadotropin (eCG) production by the fetally derived endometrial cups appears to be necessary for the establishment and maintenance of normal equine pregnancy. Starting at about the 27th day of pregnancy, an equatorial band of trophectodermal cells on the surface of the spherical conceptus forms the chorionic girdle. This girdle consists initially of flat trophectodermal epithelium which corrugates into folds as the cells proliferate. The folds are then pressed against the uterine epithelium by expansion of the conceptus. The cells on the apices of the folds become binucleate ...
Sims D, Horne MM, Creighan M, Donald A.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...
Cahill JI, Goulden BE.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...
Bouillant AM, Becker SA.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...
Lindholm A, Johansson HE, Kjaersgaard P.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...
de Paz Cabello P, Chamorro CA, Sandoval J, Fernandez M.The mechanical papillae of the horse and cow were studied by scanning electron microscopy in order to determine their morphostructural characteristics and the differences between the two species. The horse has only thin, small and interlaced filiform papillae, while the cow shows robust and more ordered filiform papillae. Furthermore, the cow tongue presents conical and lenticular papillae surrounded by a papillary groove. A characteristic distribution of stratified scales and channeled tracts is observed in conical and lenticular papillae but not in the filiform papillae. The morphostructural...
Almahbobi G, Papadopoulos V, Carreau S, Silberzahn P.Two ultrastructurally distinct types of Leydig cells were observed in the equine testis. Whereas the adult testis exhibited both postpubertal and adult Leydig cells, the testis of the pubertal horse contained only the postpubertal type, and that of the aged horse contained only the adult type. However, Percoll-purified testicular preparations from pubertal, adult, and aged horses all exhibited two distinct Leydig cell populations. The quantitative distribution and the functional characteristics of these Leydig cell populations (ability to bind human chorionic gonadotropin [hCG] and increase of...
Sells DM, Hildebrandt PK, Lewis GE, Nyindo MB, Ristic M.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...
Render JA, Common RS, Kennedy FA, Jones MZ, Fyfe JC.Three Quarter Horses, a stillborn filly (horse No. 1), a female fetus aborted at approximately 6 months of gestation (horse No. 2), and a 1-month-old colt that had been weak at birth (horse No. 3), had myopathy characterized histologically by large spherical or ovoid inclusions in skeletal and cardiac myofibers. Smaller inclusions were also found in brain and spinal cord and in some cells of all other tissues examined. These inclusions were basophilic, red-purple after staining with periodic acid-Schiff (both before and after digestion with diastase), and moderately dark blue after staining wi...
Ghaoui Rel-H, Thomson PC, Evans G, Maxwell WM.Membrane vesicles, separated by differential centrifugation from the seminal plasma, were detected in the sperm-rich ejaculate fractions of four boars and three stallions, and in the whole ejaculates of seven rams. The volume and percentage of vesicles, determined by a stereological technique, were higher in the sperm-rich than in the post-sperm-rich fractions of the boar and stallion ejaculates, and no vesicles were detected in the pre sperm-rich fractions. Vesicles were examined by transmission electron microscopy (TEM) and scanning electron microscopy (SEM). For boar, stallion and ram semen...
Betteridge KJ, Eaglesome MD, Flood PF.Two experiments were conducted using 14 mares. In Exp. 1, mares were inseminated with semen treated with TEPA, which, in other species, has been shown to lead to an arrest in ovum cleavage at 2--4 cells. The oviducts and/or uterus were then flushed 7--10 days after ovulation in 6 mares (Group A) or 2--6 days after ovulation in 5 mares (Group B). Fresh eggs were found in the oviduct flushes of 5 Group A and 5 Group B mares: 9 of the 10 eggs appeared to have cleaved, but none had developed beyond 16-cells. Seven eggs contained spermatozoa and 3 of 4 eggs from each group showed evidence of fertil...
Grøndahl C, Hyttel P, Grøndahl ML, Eriksen T, Gotfredsen P, Greve T.The objectives were to describe the ultrastructure of equine oocytes aspirated from small and preovulatory follicles, and to relate the ultrastructural features to follicle size and follicular fluid steroid concentrations. Mares were examined every second day by transrectal ultrasonography, and follicles measuring > 30 mm were aspirated (in vivo) using a 20-cm-long 12-gauge needle through the flank. Following slaughter, both large and small follicles were aspirated (in vitro) from six mares. The oocytes were isolated under a stereomicroscope and processed for transmission electron microscop...
Vashisht K, Rock RW, Summers BA.A 5-year-old National Show horse mare presented with a soft mass on the left dorsolateral aspect of the tongue. Over the next 2 years, the mare developed numerous, similar, coalescing masses that extended along the left dorsolateral aspect to the tip of the tongue. Microscopically, the bases for these masses were slender, fusiform, mesenchymal cells that formed compact whorls around myelinated and unmyelinated nerves. These cells were labeled by antibodies directed against vimentin but not by S-100. Ultrastructurally, multiple, concentrically arranged, long, slender cell processes, with discon...
Hardy MH, Fisher KR, Vrablic OE, Yager JA, Nimmo-Wilkie JS, Parker W, Keeley FW.The hyperextensible, fragile skin of two related horses was compared with the skin of eight normal horses. Skin sections were examined by light microscopy and transmission electron microscopy. The deep dermal layer of the dorsal abdomen was much thinner in the affected horses, and contained bundles of collagen fibers which were more loosely packed. Within individual fibers, the fibrils were frequently curved and nonparallel rather than straight and parallel. Both of the affected animals had a greater range of fibril diameters than a normal horse. They had some unusually thick fibrils with very...
Kilic S, Dixon PM, Kempson SA.Ultrastructural examinations of equine dentine found that dentinal tubules extended from the amelodentinal junction towards the pulp forming primary curvatures. The number of dentinal tubules/unit area and their diameters increased significantly from the amelodentinal junction towards the pulp cavities, particularly in regular secondary dentine, but irregular secondary (tertiary) dentine contained no dentinal tubules. Dentinal tubules contained odontoblast processes that appeared to extend as far as the amelodentinal junction, but due to iatrogenic loss during specimen preparation, odontoblast...
Lundin C, Sullins KE, White NA, Clem MF, Debowes RM, Pfeiffer CA.Twenty-two foals were divided into groups of intestinal distension and intestinal ischaemia as methods to induce peritoneal adhesions. In the first group, the lumen of a segment of distal small intestine was occluded without extramural vascular compromise and distended with lactated Ringer's solution to a constant pressure of 25 cm H2O for 2 h within the abdomen. The ischaemic group underwent 70 mins total vascular occlusion of identical segments of bowel. Serosal biopsies were obtained before and after each experimental procedure and following 60 mins of reperfusion. Similar biopsies were har...
Lowden S, Heath T.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.
Hurtgen JP, Johnson LA.During a 2-year period, 7 stallions were identified as having ejaculated spermatozoa characterized by a high incidence (27-74%) of acrosomal abnormalities. The most frequent abnormality of the acrosome was the 'knobbed sperm' defect which was observed in nigrosin--eosin, Giemsa, and haematoxylin and eosin stained semen smears under light microscopy, in buffered formal--saline and in glutaraldehyde-fixed wet mounts under phase contrast and differential interference microscopy, and in glutaraldehyde-fixed spermatozoa with electron microscopy and scanning electron microscopy. The defect was visib...
French KR, Pollitt CC.Acute laminitis is characterised by hoof lamellar dermal-epidermal separation at the basement membrane (BM) zone. Hoof lamellar explants cultured in vitro can also be made to separate at the basement membrane zone and investigating how this occurs may give insight into the poorly understood pathophysiology of laminitis. Objective: To investigate why glucose deprivation and metalloproteinase (MMP) activation in cultured lamellar explants leads to dermo-epidermal separation. Methods: Explants, cultured without glucose or with the MMP activator p-amino-phenol-mercuric acetate (APMA), were subject...
Riviere JE, Coppoc GL, Hinsman EJ, Carlton WW, Traver DS.Gentamicin pharmacokinetics and nephrotoxic potential were evaluated in twelve 2 to 3 month-old horses. Whereas recent evidence in our clinic indicated that young horses may be especially susceptible to gentamicin nephrotoxicity, young rabbits and rats are usually resistant. Gentamicin (4.5 mg/kg) was given by rapid intravenous injection. Serum gentamicin concentrations over a 13-hour period were fitted to an open, two-compartment, pharmacokinetic model. Subsequently, the same horses were divided into groups of 3 horses each. Each group received 0, 2.2, 4.4 or 8.8 mg gentamicin/kg, intramuscul...
Lowden S, Heath T.Lymphoid tissues in the ileum of young horses form raised plaques that are macroscopically visible from the mucosal surface. These are termed "ileal lymphoid patches". These patches are variable in size, shape and position within the ileal wall, occasionally lying along the site of mesenteric attachment. Within lymphoid patches, follicles exist in three different morphological forms: follicle/dome structures, proprial follicles, and lymphoglandular complexes (LGCs). In follicle/dome structures, the majority of the follicle lies in the submucosa and merges with a dome in the lamina propria thro...
Sharma R, Barakzai SZ, Taylor SE, Donadeu FX.Despite the high prevalence of skin conditions in the horse, there is a dearth of literature on the culture and biology of equine skin cells, and this is partially attributable to the lack of suitable in vitro skin models. The objective of this study was to develop a three-dimensional (3D) culture system that would support the proliferation and differentiation of equine keratinocytes, similar to that observed in natural epidermis. Cell monolayers were obtained from explants of equine skin and serially passaged as highly pure keratinocyte populations (> 95% of cells), based on their express...
Minelli A, Moroni M, Martínez E, Mezzasoma I, Ronquist G.Equine seminal plasma was shown to contain membrane vesicles that are similar to the well characterized prostasomes in human seminal plasma. Determination of nucleoside and nucleotide concentrations of these particles have shown that ATP, ADP and adenosine are the main components of the nucleotidic pool. 5' nucleotidase, endopeptidase and dipeptidyl peptidase i.v. activities have been found on the surface of the particles. The interaction between these prostasome-like vesicles and spermatozoa was demonstrated by electron micrograph scans which revealed the steps of a fusion-like process leadin...
Grosche A, Morton AJ, Graham AS, Sanchez LC, Blikslager AT, Polyak MM, Freeman DE.Ultrastructural changes in the epithelium can provide information on early changes in barrier properties, repair and inflammation in equine colon after ischaemia and reperfusion (I/R). Objective: To describe the morphology and ultrastructure of the epithelium in equine large colonic mucosa after I/R, and the response of inflammatory cells to injury. Methods: Ischaemia was induced for 1 h followed by 4 h of reperfusion in a 40 cm segment of the pelvic flexure in 6 horses. Mucosal biopsies before and after ischaemia, and after 1, 2 and 4 h of reperfusion were fixed in glutaraldehyde/paraformalde...
Veldman JE, Keuning FJ, Molenaar I.Two times sublethal total body-X-irradiation with weekly local thymus irradiation established a T-cell deprived experimental model in rabbits. Humoral immunity reactions in draining lymph nodes have been analyzed histologically and at the submicroscopical level after challenge with Salmonella Java vaccine, horse spleen ferritin, horse-gamma-globulin, a chemical sensitizer oxazolone (2 phenyl-4-ethoxymethylene-5-oxazolone) and after skin allografting respectively. The time sequence studies in these animals with an 'isolated B-cell system' are compared with similar experiments in normal non-irra...
Saville WJ, Dubey JP, Oglesbee MJ, Sofaly CD, Marsh AE, Elitsur E, Vianna MC, Lindsay DS, Reed SM.Sarcocystis neurona and Sarcocystis fayeri infections are common in horses in the Americas. Their antemortem diagnosis is important because the former causes a neurological disorder in horses, whereas the latter is considered nonpathogenic. There is a concern that equine antibodies to S. fayeri might react with S. neurona antigens in diagnostic tests. In this study, 4 ponies without demonstrable serum antibodies to S. neurona by Western immunoblot were used. Three ponies were fed 1 x 10(5) to 1 x 10(7) sporocysts of S. fayeri obtained from dogs that were fed naturally infected horse muscles. A...
Hay MF, Allen WR.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...
Chamorro CA, de Paz P, Sandoval J, Fernandez JG.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...
Cheng FP, Gadella BM, Voorhout WF, Fazeli A, Bevers MM, Colenbrander B.The aim of the present study was to investigate whether the induction of stallion sperm acrosome reaction (AR) by progesterone is mediated by binding of progesterone to a receptor on the sperm plasma membrane or to an intracellular progesterone receptor. Progesterone-BSA conjugate labeled with fluorescein isothiocyanate (P-BSA-FITC) in combination with a vital stain, ethidium homodimer, was applied to visualize the presence of the progesterone receptor on living spermatozoa. Alternatively, an indirect immunofluorescence technique employing a monoclonal antibody (C-262) against human intracellu...
