Topic:Microscopy
Microscopy in equine research involves the use of various microscopic techniques to study the cellular and subcellular structures of horses. This field encompasses the examination of tissues, cells, and microorganisms to gain insights into equine health, disease mechanisms, and physiological processes. Techniques such as light microscopy, electron microscopy, and fluorescence microscopy are employed to observe and analyze samples at high magnification, providing detailed information on morphology and pathology. Microscopy aids in the diagnosis of diseases, identification of pathogens, and evaluation of cellular responses to treatments. This page compiles peer-reviewed research studies and scholarly articles that explore the applications, methodologies, and findings of microscopy in the study of equine biology and medicine.
Malignant granulosa-theca cell tumor in a two-year-old Miniature Horse. 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...
Encephalitozoon cuniculi placentitis and abortion in a quarterhorse mare. Encephalitozoon cuniculi is a microsporidial parasite, which has rarely been reported to cause placentitis in animals. A late-term aborted fetus and placenta from a Quarterhorse were presented to the Livestock Disease Diagnostic Center, University of Kentucky, for diagnostic examination. There was a necrotizing placentitis, with distension of many chorionic epithelial cells by intracytoplasmic vacuoles containing 1-2-microm-diameter, elongated, gram-positive organisms. The organisms were identified as E. cuniculi by electron microscopy and by polymerase chain reaction using primers to microspo...
Value of histopathology in vitiligo. Histopathologic studies of vitiligo have been rather limited in number, thus the microscopic features of this common disorder are not very well known. Methods: Skin specimens from 20 human vitiligo patients and skin specimens from five equine vitiligo patients were studied by light and transmission electron microscopy. Conclusions: Absence of melanocytes, increased number of Langerhans' cells, epidermal vacuolization, thickening of the basement membrane, T-cell inflammatory infiltrate, and neural alterations were noted in the vitiligo lesions. These results may explain the development of depig...
Deformation behaviour and damage accumulation of cortical bone specimens from the equine tibia under cyclic loading. Despite its clinical importance, the fatigue behaviour of cortical bone has not been examined as widely as its static behaviour. In the present study, specimens from the tibiae of horses have been subjected to load-controlled single step tests. The cyclic deformation behaviour was described by the development of stress-strain hysteresis parameters over the lifetime. The fatigue behaviour of bone is characterised by cyclic softening which is most distinctive towards the end of the lifetime. The microstructural damage accumulated during cyclic loading results in a loss of stiffness, asymmetrical...
Equine cortical bone exhibits rising R-curve fracture mechanics. Previous studies of the fracture properties of cortical bone have suggested that the fracture toughness increases with crack length, which is indicative of rising R-curve behavior. Based on this indirect evidence and the similarity of bone to ceramic matrix composites, we hypothesized that bone would exhibit rising R-curve behavior in the transverse orientation and that the characteristics of the R-curves would be regionally dependent within the cortex due to variations in bone microstructure and toughening mechanisms. To test these hypotheses, we conducted R-curve experiments on specimens fro...
Microscopic localization of active gelatinases in equine osteochondritis dissecans (OCD) cartilage. To investigate the relationship between matrix metalloproteinase (MMP) activity and osteochondritis dissecans (OCD) in the equine joint. Methods: Equine articular cartilage was obtained from normal (N = 8) and osteochondrotic (OCD) (N = 6) femoropatellar joints from horses at necropsy. The activity of gelatinase MMPs was determined in sections of cartilage by in situ gelatin zymography. Results: Gelatinase activity was markedly increased in articular cartilage obtained from OCD samples and was particularly prominent in the deep cartilage zone. Activity was only seen in the pericellular area of...
Serum fluoride concentrations, biochemical and histopathological changes associated with prolonged sevoflurane anaesthesia in horses. The volatile anaesthetic sevoflurane is degraded to fluoride (F-) and a vinyl ether (Compound A), which have the potential to harm kidney and liver. Whether renal and hepatic injuries can occur in horses is unknown. Cardiopulmonary, biochemical and histopathological changes were studied in six healthy thoroughbred horses undergoing 18 h of low-flow sevoflurane anaesthesia. Serum F- concentrations were measured and clinical laboratory tests performed to assess hepatic and renal function before and during anaesthesia. Necropsy specimens of kidney and liver were harvested for microscopic examinat...
Comparison between glycerol and ethylene glycol for the cryopreservation of equine spermatozoa: semen quality assessment with standard analyses and with the hypoosmotic swelling test. The aims of this study were to compare glycerol (G) at customary concentrations and ethylene glycol (EG) as cryoprotectants for stallion semen in a skimmed milk (SM) extender, to test different EG concentrations and to compare the results of manual and computerized analysis with the hypoosmotic swelling (HOS) test. Ejaculates from two stallions were collected over 3 weeks (6 ejaculates per stallion), diluted in a SM based extender, divided into 4 fractions, centrifuged and diluted again to a concentration of 100 x 10(6) mL(-1) progressive motile spermatozoa (PMS) in addition with the cryoprote...
Carbonic anhydrase activity and sweat gland morphology in trained and untrained Standardbred trotters. Sweat gland morphology and carbonic anhydrase (CA) distribution was studied after exercise in trained and untrained horses using a histochemical technique and light microscopic image analysis. Three trained and 3 untrained Standardbred trotters performed an exercise test (20 min trot at 6 m/s with 5 min walk at 1.8 m/s in the beginning and end) on a high-speed treadmill at 35 degrees C. Skin biopsies were taken before exercise and after trot. The fluid loss after exercise was 10, 12 and 12 g/kg bwt in the untrained horses and 4, 6 and 11 g/kg in the trained. Trained horses had a larger cell ar...
Method for preparing thin sections of untreated equine hoof horn for electron microscopic examination. 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...
Fourier transform infrared microspectroscopic investigation of the organic and mineral constituents of peritubular dentin: a horse study. Peritubular dentin (PTD) is a relatively dense mineralized tissue surrounding tooth dentin tubules, whose composition and mode of formation are still unclear. Fourier transform infrared microspectroscopic studies of the organic and mineral components of the highly developed horse PTD indicate that the peritubular matrix is less abundant than the intertubular matrix but is also mainly composed of collagen, which is more hydrated. These data suggest that most of the crystals are located outside the collagen fibrils and probably not associated with protein components. The crystals in PTD have nea...
Langerhans cells within the follicular epithelium and the intradermal sweat duct in equine insect hypersensitivity “Kasen”. 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...
Three-dimensional architecture of the myosalpinx in the mare as revealed by scanning electron microscopy. 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...
The effect of intra-articular methylprednisolone acetate and exercise on equine carpal subchondral and cancellous bone microhardness. Dorsal carpal osteochondral injury is a major cause of lameness in horses undergoing high intensity training. Intra-articular corticosteroid treatment is used commonly to manage exercise-associated articular pain, but its use remains highly controversial in the equine athlete. This project, therefore, aimed to compare the mechanical properties of intra-articular MPA and diluent-treated middle carpal subchondral and cancellous bone in horses undergoing a short-term treadmill exercise programme. It was hypothesised that subchondral and cancellous bone mechanical properties are influenced by intr...
A study of the ultrastructure and staining characteristics of the ‘dental star’ of equine incisors. 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...
Horse lumbrical muscle: possible structural and functional reorganization in regressive muscle. 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...
Stiff and strong compressive properties are associated with brittle post-yield behavior in equine compact bone material. Our hypothesis was that post-yield mechanical behavior of compact bone material in compression, defined as the stress, strain, or energy absorbed between 0.2% strain-offset and the point of maximum stress, is correlated with material density, modulus, strength, histomorphometric evidence of remodeling, and post-failure gross specimen morphology. Post-yield behavior of compact bone material from the third metacarpal bone of 10 horses, ages 5 months to 20 years, was investigated using single-load compression-to-failure. The post-yield stress, strain, and absorbed energy were compared with the co...
Ultrastructural aspects of the oesophageal and reproductive systems of the equine parasite Strongylus vulgaris. 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...
Identification and distribution of a novel Malassezia species yeast on normal equine skin. This study aimed to investigate the distribution of Malassezia species yeasts on the skin of healthy horses. Acetate tape samples were obtained from the lip, axilla, interbulbar region, groin and anus of 12 healthy horses. The samples were stained and examined microscopically and sites harbouring yeast-like organisms were identified. Contact plates were applied to the skin at these sites and cultured at 26 degrees C and 32 degrees C. No growth was obtained on horse blood, Sabouraud's dextrose or modified Dixon's agar. A pure growth of a Malassezia-type organism was obtained on Sabouraud's dext...
Some morphological aspects of Cylicocyclus brevicapsulatus (Nematoda: Cyathostominae) parasite of horse. This paper describes some morphological aspects of Cylicocyclus brevicapsulatus (Ihle, 1920) (Nematoda: Cyathostominae) from Equus caballus in Brazil. The worms were studied using an optical microscope (measurements and illustrations) and a scanning electron microscope for a more detailed examination of the external morphology. The buccal capsule is very short, with a very thin wall, and the dorsal gutter is absent. Other morphological aspects are described including measurement of the spicules and gubernaculum.
Normal structure and age-related changes of the equine retina. Investigations of the pathophysiology of ocular diseases require a detailed knowledge of the microanatomy of the eye. The available information is still inadequate for the equine retina despite the importance of eye diseases in equine medicine. Here we provide a comprehensive analysis of the histologic features of the horse eye as a reference for future studies. Thirty normal eyes of 15 healthy horses were examined immediately after slaughter. The retina of the horse differs considerably in the degree and quantity of neurons and glial elements as well as in vascular patterns compared to the re...
Comparative evaluation of nuclear morphology of equine oocytes aspirated in vivo and stained with Hoechst and orcein. Nuclear maturation of equine oocytes was assessed immediately after in vivo collection. A double-staining technique (Hoechst and orcein) was used on the same oocytes to visualize nuclear morphology, i.e. to evaluate the chromatin configurations of each oocyte after Hoechst in relation to the nuclear morphology after orcein staining. The proportion of oocytes evaluated as germinal vesicle stages was significantly (p < 0.02) lower after Hoechst (14.5%) than after orcein staining (29.0%), while the incidence of the so-called dense chromatin stage was assessed to be higher (p < 0.05) after H...
Cultivation and characterisation of primary and subcultured equine keratinocytes. We describe the establishment and characterisation of equine keratinocyte cultures with maintenance of a high proliferative capacity up to the second passage. Improved attachment and growth were obtained by seeding primary cells on equine feeder layers. Subcultured keratinocytes showed optimal growth when seeded on collagen type I. The proliferation rate of cells on this substrate exceeded that seen for cells seeded on equine feeder layers. By immunohistochemistry, epithelial origin and state of differentiation of the equine keratinocytes were determined. They expressed keratin and desmoplakin...
Surface immunolocalisation of HPr in the equine pathogen Streptococcus equi. We have investigated the surface localisation of the phosphotransferase system protein HPr in the equine pathogen Streptococcus equi subsp. equi using immunogold localisation and transmission electron microscopy. Like the LppC acid phosphatase lipoprotein, a reference surface antigen, the S. equi HPR could be clearly detected on the surfaces of intact cells. This study is consistent with previous reports that some streptococcal HPr is cell surface associated and suggests that the extracytoplasmic mobilisation and transfer of phosphate groups by streptococci warrant further investigation.
Development of the equine brain motor system. The purpose of the present study was to demonstrate the structural maturation of the horse brain in the critical period of development emergence of coordinated locomotion. Equine brains from 14 days before expected birth to adulthood were fixed in formaldehyde and embedded in paraffin. After taking the outer parameters of the brains, full series of large-area coronal sections were prepared on a special microtome and stained with Nissl's cresyl violet and Haidenhain's iron-haematoxylin. Microscopic images of sections were digitized and were subjected to computer-aided image analysis. The gross ...
Prevalence and macro- and microscopic lesions produced by Gasterophilus nasalis (Diptera: Oestridae) in the Botucatu Region, SP, Brazil. The objective of the present study was to investigate the prevalence of Gasterophilus nasalis larvae in Botucatu, the central west region of São Paulo State, Brazil, and to describe the lesions caused by the parasite. The climate of Botucatu is warm and rainy during the months of December through March and cool and dry during the months of May through August. The prevalence of G. nasalis was 16.84%, and the period of peak infestation corresponded to the months of cold and dry weather. The lesions detected at the sites of larval attachment were examined macro- and microscopically. Erosions and...
In vivo imaging of physiological angiogenesis from immature to preovulatory ovarian follicles. To develop a model for the study of physiological angiogenesis, we transplanted ovarian follicles onto striated muscle tissue and analyzed the process of microvascularization in vivo using repeated fluorescence microscopy. Follicles were mechanically isolated from unstimulated as well as pregnant mare's serum gonadotropin (PMSG)- or PMSG/luteinizing hormone (LH)-stimulated Syrian golden hamster ovaries and were transplanted as free grafts into dorsal skinfold chambers of untreated or synchronized hamsters. Follicles lacking thecal cell layers did not vascularize regardless whether harvested fr...
The application of three-dimensional internal structure microscopy in the observation of mare ovary. The ovary of the mare has a unique structure which differs totally from that of other mammals. However, because of its relatively large size, conventional histological techniques were unsuitable for the observation of the internal structure of the whole ovary. Three-dimensional internal structure microscopy (3D-ISM) consists of a cryotome-CCD camera-laser disc recorder-PC-based control system coupled with a graphic workstation. The internal structure of the ovary is observed by processing over more than 1,000 stored images of serially sliced surfaces of each frozen equine ovary. The 3D reconst...
Quantitative analysis of the optic nerve of the horse (Thoroughbred). Three optic nerves (L1, R2, R3) 12-18 mm behind the eyeball of the horse (Thoroughbred) were investigated quantitatively under light and electron microscopes. Thin sections at the thickness of 0.35 microm were cut, stained by toluidine blue and observed under the light microscope. The areas of the optic nerve and the axon bundles were 20.03 +/- 1.04 and 16.59 +/- 0.79 mm2 (mean +/- SD, n=3), respectively. The axon numbers for optic nerve L1, R2 and R3, estimated from light micrographs, were about 481 x 10(3), 543 x 10(3), and 494 x 10(3), respectively. Axons of optic nerve L1 were also counted...