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Topic:Histology
Histology in horses involves the microscopic examination of tissues to understand their structure and function. This field of study provides insights into the cellular composition and architecture of equine tissues, aiding in the diagnosis of diseases and the assessment of tissue health. Histological analysis is used to identify pathological changes, such as inflammation, neoplasia, or degenerative conditions, by examining tissue samples obtained through biopsies or necropsies. Common tissues studied in equine histology include skin, muscle, bone, and internal organs. This page compiles peer-reviewed research studies and scholarly articles that explore histological techniques, findings, and their applications in equine veterinary medicine.
Prognostic factors and survival of horses with ocular/adnexal squamous cell carcinoma: 147 cases (1978-1988). Between January 1978 and December 1988, 147 horses with ocular/adnexal squamous cell carcinoma (SCC) were admitted to the Colorado State University Veterinary Teaching Hospital (CSU-VTH). Diagnosis was confirmed by histologic examination of appropriate tissue specimens. Medical records and communication with owners, referring veterinarians, or both provided information regarding initial examination, treatment at the CSU-VTH, and final outcome. At initial examination, 123 (83.7%) horses had unilateral involvement and 24 (16.3%) horses had bilateral involvement. The nictitating membrane, nasal c...
Effect of age and season on the establishment of spermatogenesis in the horse. To determine the age at which adult values for hormonal and testicular characteristics are established, testes and blood from 123 slaughtered horses, aged 1-5 years, were compared. Serum concentrations of follicle-stimulating hormone (FSH), luteinizing hormone (LH) and testosterone (T) and intratesticular testosterone (ITT) were determined by radio-immunoassay. Specimens were obtained in the non-breeding (n = 46) or breeding (n = 43) season in Experiment 1 (Exp. 1) and in the breeding (n = 34) season in Experiment 2 (Exp. 2). Testicular parenchyma was fixed in glutaraldehyde and homogenized to...
Histology and morphometry of Strongylus vulgaris-mediated equine mesenteric arteritis. Histological and morphometric evaluation of equine cranial mesenteric arteries was performed on 239 and 89 arteries, respectively. Histological examination revealed that thrombosis and the severity of inflammation varied on a seasonal basis and were directly associated with larval presence. Intimal and adventitial fibrosis were generally of greater severity than medial fibrosis. Fibrosis of the vasa vasorum was less frequent than fibrosis of the artery itself. Morphometry revealed a significant increase in intimal, adventitial and, to a lesser extent, medial area in affected as compared with n...
Effects of intra-articular administration of methylprednisolone acetate on normal equine articular cartilage. The effects of the corticosteroid 6-alpha-methylprednisolone acetate on normal equine articular cartilage were evaluated, using the middle carpal joint in 4 clinically normal young horses. One middle carpal joint of each horse was injected 3 times with 100 mg of 6-alpha-methylprednisolone acetate, at 14-day intervals. The opposite middle carpal joint (control) was injected with 2.5 ml of lactated Ringer solution at the same intervals. Effects were studied until 8 weeks after the first injection. Evaluation included clinical and radiographic examination, and gross, microscopic, and biochemical ...
Maturation of oocytes from normal and atretic equine ovarian follicles as affected by steroid concentrations. The ovaries of 23 mares were collected at slaughter during April-June and follicles (4-40 mm in diameter) were dissected and punctured to obtain oocytes for culture. The follicles were grouped according to histology: (a) normal, (b) showing primary and (c) secondary atresia. Antral fluid was analyzed for steroid content; oestradiol and testosterone (but not progesterone or androstenediol) were closely correlated with follicle size and histological state. Oocytes were cultured early after slaughter in Medium 199 (Difco OSI, France) or Medium B2, the highest percentage of oocytes reaching Metaph...
Pathological changes of the mare endometrium and genotypes for transferrin and ELA. Histological features of the endometrium, as assessed in biopsy samples, were related to Standardbred mare genotypes for transferrin, esterase (as a control) and equine leucocyte antigens (ELA). Pathological changes were found more frequently in each successively older age group of mares. Among mares aged 6-19 years, there were significant pathologic changes on first examination following an infertile breeding season for 46 of 90 (51%) of transferrin homozygotes and 50 of 146 (34%) of transferrin heterozygotes. The difference between the two groups was significant for the total data (chi 1(2) ...
The placenta as a determinant of fetal well-being in normal and abnormal equine pregnancies. One hundred twenty-four horse placentas were evaluated according to gross appearance, weight and surface area. Grossly abnormal placentas were photographed, and histological sections were taken from abnormal appearing areas, and from representative areas (pregnant horn, non-pregnant horn, body and cervical pole) in both normal and abnormal placentas. Information about the resulting foals was obtained and correlations examined. Histological sections were reviewed and related to the resulting foals. Four normal fresh placentas were infused with dyes to ascertain the blood supply to various areas...
Maximum velocity of shortening of three fibre types from horse soleus muscle: implications for scaling with body size. 1. To explore how maximum velocity of shortening (Vmax) of fibres varies within one muscle and how Vmax varies with body size, we measured Vmax of muscle fibres from soleus muscle of a large animal, the horse. 2. Vmax was determined by the slack test on skinned single muscle fibres at 15 degrees C during maximal activation (pCa = 5.2). The fibre type was subsequently determined by a combination of single-cell histochemistry and gel electrophoresis of the myosin light chains. 3. Vmax values for the type I, IIA and IIB muscle fibres were 0.33 +/- 0.04 muscle lengths/s (ML/s) (+/- S.E.M., n = 6),...
Immunohistochemical detection of papillomavirus structural antigens in animal hyperplastic and neoplastic epithelial lesions. One hundred and seventy-two hyperplastic and neoplastic epithelial lesions from 8 different mammalian and 1 avian species have been tested with an immunohistochemical technique to detect papillomavirus structural antigens. Selected lesions were diagnosed histologically as papilloma, fibropapilloma, equine sarcoid, squamous cell carcinoma, basalioma, epulis, keratoacanthoma, trichoepithelioma, pilomatrixoma, epidermal inclusion cyst, and hyperkeratotic or acanthotic epidermal lesions. Positive nuclear staining was detected in 14 out of 23 papillomas, 8 out of 32 fibropapillomas and in 1 out of ...
Immunocytochemical demonstration of proopiomelanocortin-derived peptides in pituitary adenomas of the pars intermedia in horses. Adenomas of the pars intermedia from 19 horses and normal pituitary glands from seven horses were evaluated histologically and immunocytochemically for adrenocorticotropic hormone (ACTH), alpha-melanocyte-stimulating hormone (alpha-MSH), beta-endorphin (beta-END), proopiomelanocortin (POMC), prolactin, neuron specific enolase, and glial fibrillary acidic protein (GFAP). The 26 horses ranged in age from 7 to 31 years. Histologically, all adenomas had a uniform pattern characterized by cords of large columnar cells forming palisades and pseudoacini separated by a delicate fibrovascular stroma. I...
Interspecies and interregional analysis of the comparative histologic thickness and laser Doppler blood flow measurements at five cutaneous sites in nine species. Studies in dermatology, cutaneous pharmacology, and toxicology utilize skin from different animal species and body sites. However, regional differences exist in topical chemical percutaneous absorption studies in man and in animal. The objective of this study was to compare epidermal thickness and number of cell layers across species and body sites using both formalin-fixed paraffin and frozen sections. Cutaneous blood flow determined by laser Doppler velocimetry (LDV) was compared to histologic data. Six animals of each of the following species were used: monkeys, pigs, dogs, cats, cows, hors...
Cultivation of tissue from the matrix of the stratum medium of the equine and bovine hoof walls. Explants from the matrix of the stratum medium of the wall of the equine and bovine hoof each were cultured on a microporous membrane, using a standard culture medium. After incubation at 37 C, the outgrowth was a mixture of keratinocytes and fibroblasts, with predominance of the latter. After incubation at 34 C, the keratinocytes dominated, covering the lateral surfaces of the explant as well as the basal surface. Lateral outgrowth of keratinocytes was observed at the borderline of the original epidermis and at the borderline of the explant's contact with the membrane. Epithelial outgrowth fr...
Mast cells in normal and pathological specimens of the equine lung. In lungs from 22 horses, the number and type of mast cells in histologically normal specimens were compared with those in specimens with various histological lesions. Tissues fixed in Carnoy's solution were superior to those fixed in formalin for the identification of mast cells. Fixation of lung specimens from eight horses in Carnoy's solution and formalin allowed the identification of two subpopulations of mast cells: formalin-sensitive, which predominated and formalin-resistant. Specimens with mild chronic tracheitis and mild and moderate chronic bronchitis generally had slight increases in...
Two rare cutaneous neoplasms in horses: apocrine gland adenocarcinoma and carcinosarcoma. Two rare equine cutaneous neoplasms, an apocrine gland adenocarcinoma and a carcinosarcoma were diagnosed in a 17-year-old pony and a 14-year-old mare, respectively. The apocrine gland adenocarcinoma was present on the prepuce. Histologically, papillary projections of low cuboidal to columnar epithelial cells were generally well differentiated, and surrounded dilated acini. Stromal invasion was present, but vascular and lymphatic invasion was not seen. The carcinosarcoma was present in the right flank of the mare. Two discrete cell populations were characterized histologically. One portion of ...
Malignant melanoma in the foot of a horse. A 24-year-old horse had a malignant melanoma of the right forefoot. Because surgical excision of the melanoma was incomplete, as determined by histologic examination of the excised tissue margins, the tumor margins were injected with a matrix therapeutic implant containing cis-diamminedichloroplatinum, epinephrine, and purified bovine collagen matrix. The foot healed and the horse remained clinically free of disease for 26 months before recurrence of malignant melanoma. Surgical exploration of the digit revealed extensive involvement of the foot, and the horse was euthanatized.
Ethmoidal hematoma in nine horses. Ethmoidal hematoma was diagnosed in 9 horses by results of physical examination, endoscopy, radiography, and histologic examination of tissues. The horses had stertorous breathing (n = 4) or intermittently sanguineous nasal discharge (n = 7). All horses underwent sinusotomy and extirpation of the lesion. At reexamination 15 to 104 months after surgery (mean, 61 months), 3 horses had recurrence of ethmoidal hematoma, and 1 horse had ethmoidal hematoma involving the contralateral ethmoturbinates. One of the horses with recurrence of ethmoidal hematoma also developed a contralateral lesion; both ...
Horner’s syndrome in the horse: a clinical, experimental and morphological study. A clinical case of Horner's syndrome is described in a Standardbred horse, and the various symptoms of cranial sympathetic denervation are studied in two ponies after experimental transection of the left cervical sympathetic trunk and vagosympathetic trunk, respectively. The most prominent symptoms of equine Horner's syndrome were ptosis, local sweating and increased cutaneous temperature in the denervated area. Enophthalmos, miosis and increased lacrimation were also observed but these symptoms were mild, variable and difficult to ascertain. Prolapse of the third eyelid was not noticed. Conco...
Histologic and ultrastructural studies of dermal sarcoma of walleye (Pisces: Stizostedion vitreum). Sixty-seven adult walleye fish were examined by light and transmission electron microscopy. The fish were affected by a mesenchymal tumor previously termed Walleye Dermal Sarcoma that commonly affects up to 27% of the population seasonally. Biopsies from 24 fish were collected, and complete postmortem examinations were performed on 43 fish. Grossly, the tumors had the appearance of randomly distributed, often clustered, spherical nodules, 2-5 mm in diameter with a smooth and often ulcerated surface. The tumors arose from the superficial surface of scales and consisted of fibroblast-like cells ...
Histochemical profile of articularis humeri muscle in the horse. In this study the histochemical fiber type analysis of the articularis humeri muscle of the horse was performed. This muscle is composed of type I and type IIA fibers. A large number of spindles has been observed and the presence of these receptors could help to understand the role played by this muscle.
Distribution of labelled cysteine and methionine in the matrix of the stratum medium of the wall and in the laminar layer of the equine hoof. The distribution of 35-S-labelled cysteine and methionine in the epidermis of the equine hoof following 2 hours of intra-arterial injection was studied by microautoradiography. Material for autoradiography was obtained by biopsy about 1 hour after termination of the intra-arterial injection and also 10 and 40 days later. In the specimens obtained one hour after the injection of labelled cysteine and methionine, the amount of radioactivity in the matrix and in the most proximal part of the laminar layer was very high. There was a clear difference between the distribution of the two labelled ami...
Ultrastructural morphology of hypomelanosis in equine cutaneous papilloma. The morphology of hypomelanosis occurring in experimentally induced equine papillomas was investigated. Histologically, dopa-positive functioning melanocytes were decreased in number from the basal layer in the epidermis. Electron-microscopically, melanogenic organelles in the melanocytes were degenerate and melanosomes were decreased in number and size. In addition, the melanocytes had some abnormal melanosomes including melanosome complexes and giant melanosomes. Some abnormal melanosomes were also present in the keratinocytes. The hypomelanosis seemed to be related to a disturbance in melan...
Neuroaxonal dystrophy associated with vitamin E deficiency in two Haflinger horses. Neuroaxonal dystrophy and minimal diffuse degenerative myelopathy was diagnosed in two female full sibling, 1- and 2-year-old, Haflinger horses. Both animals developed slowly progressive ataxia from the age of 4 months. Clinical signs, which were more prominent in the hind legs, included hypermetria and dysmetria. Histological examination revealed neuroaxonal dystrophy characterized by spheroid formation, vacuolation, astrogliosis and lipofuscin pigment deposition in macrophages and neuronal perikarya. These changes were restricted to the gracilis and cuneate nuclei, nucleus of the solitary tr...
Equine synovial tendon sheaths and bursae: an histological and scanning electron microscopical study. The structure of equine synovial tendon sheaths and bursae has been examined by light and scanning electron microscopy. Tissue samples were obtained from horses of various types and ages with no clinical evidence of sheath or bursal disorders. The interior of both structures was lined by a cellular layer superimposed on a vascular zone supported by a fibrous layer. The pattern of cell distribution of the lining varied from site to site within the same structure depending on the nature of the underlying tissue and on the amount of movement to which the structure was subjected. The cellular laye...
Isolation and staging of horse seminiferous tubules by transillumination. Stages of the spermatogenic cycle in the horse were determined by trans-illumination of enzymically isolated, seminiferous tubules and were verified by whole-mounted tubules observed by Nomarski optics and by conventional histology. Isolated tubules were obtained from young (less than 2 years) and adult (4-10 years) horses by enzymic digestion. Dispersed tubules were separated into three different groups based on the presence, size, and intensity of a dark region in the centre of the tubules: (1) pale--homogeneously light, (2) spotty--light on the periphery with a wide spotty region in the cen...
A comparison of repair methods for gap healing in equine flexor tendon. In nine horses (18 forelimbs), a 3 cm section of superficial digital flexor tendon was removed and the tendons were repaired with immobilization for 6 weeks and (1) no suture (n = 6); (2) a double locking loop tenorrhaphy with carbon fiber (n = 6); or (3) a double locking loop tenorrhaphy with size 2 nylon suture (n = 6). Clinical assessment, gross evaluation, morphometry, histology, and mechanical testing were performed on two limbs from each treatment group at weeks 6, 12, and 24. At weeks 6 and 12, the unsutured tissue was less mature than the tissue sutured with nylon. By week 24, the carb...
Staging equine seminiferous tubules by Nomarski optics in unstained histologic sections and in tubules mounted in toto to reveal the spermatogenic wave. Nomarski optics were used to identify stages of the spermatogenic cycle of seminiferous tubules in sectioned tissue or in whole dispersed tubules and to characterize the equine spermatogenic wave. Embedded tissues were sectioned at 20 microns. Whole dispersed tubules were obtained by enzymatic digestion of thin slices of fresh testis. Dispersed tubules were fixed, dehydrated in graded levels of alcohol, infiltrated with Epon, and mounted in toto on glass slides. Stages of the spermatogenic cycle could be identified under Nomarski optics in both histologic sections and tubules mounted in toto. ...
Jugular thrombophlebitis resulting from an anaesthetic induction technique in the horse. Forty-eight hours after general anaesthesia was induced by glycerol guaiacolate and thiopentone sodium in 10 horses, the jugular veins were dissected out at post-mortem and examined visually and histologically. All veins showed a marked thrombophlebitis involving the media and intima at the site of injection. The influence of catheter composition, catheter placement and chemical composition on the occurrence of the thrombophlebitis is discussed. It is concluded that the thrombophlebitis was chemically induced.
Effect of intestinal resection on two juvenile horses with granulomatous enteritis. Two horses were presented with lethargy, weight loss, anorexia, and swelling of the limbs and ventral body wall. One horse, a 12-month-old American Paso Fino colt, also had acute abdominal pain. The other horse, a seven-month-old Tennessee Walking Horse (TWH) filly passed diarrheic stools during the initial examination. Each horse had low serum protein, neutropenia, and a normal packed cell volume (3.2 g/dl, 1300 cells/ul, and 38%, respectively, for the colt, and 2.4 g/dl, 696 cells/ul, and 44%, respectively for the filly). After intravenously administering plasma, the colt's PCV dropped to 23...
Contracture test and histologic and histochemical analyses of muscle biopsy specimens from horses with exertional rhabdomyolysis. Biopsy specimens of the cutaneous omobrachialis muscle were obtained from 10 horses with a problem of myositis from mild exercise. One horse had been evaluated previously and malignant hyperthermia-like contractures developed in its muscle biopsy specimen during the contracture test. In this study, the halothane-caffeine contracture test and histologic and histochemical evaluations were performed on muscle biopsy specimens. In the contracture test, no muscle biopsy specimen developed contracture in the presence of 2 or 4% halothane alone. The mean (+/- SEM) caffeine-specific concentration in t...
