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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.
Fusion of the distal intertarsal and tarsometatarsal joints in the horse using intraarticular sodium monoiodoacetate. Six normal horses received 3 intra-articular injections of sodium monoiodoacetate (MIA) in the distal intertarsal (DIT) and tarsometatarsal (TMT) joints of one hindlimb. Injections were at three week intervals, and post injection pain was controlled with routine administration of phenylbutazone for five days following each injection. All horses underwent a gradually increasing exercise programme consisting of walking and trotting beginning one week after the first injection and continuing for 24 weeks. All treated joints showed increasingly severe radiographic evidence of degenerative joint di...
[The microscopic and functional anatomy of the ileal papilla (papilla ilealis) and the cecocolic valve (valva caecocolia) and the pelvic flexure (flexura pelvina) of the horse (Equus caballus)]. The histologic study on six horses of the ileo-caecal and caeco-colic junctions confirms their sphincteral structure. It appears that the activity of the muscular fibres, identified in the ileo-caecal and caeco-colic plica, modulates the curvature of the junctions and thus, blocks, as sphincters, the reflux of contents from the caecum into the ileum and from the colon into the caecum. But on the other hand, the pelvic flexure does not possess any microscopic organization to stop the reflux of contents from the dorsal colon into the ventral colon.
Primary intra-osseous carcinoma of the maxilla in a horse. An 8-year-old Hannoverian horse developed a swelling of the maxilla caused by a tumour of the hard palate. On histological examination the tumour was diagnosed as a primary intra-osseous carcinoma of the maxilla, a rare odontogenic tumour not previously described in the horse.
Duodenal glands of the pony (Equus caballus). The ultrastructure and histochemistry of the duodenal glands of the pony (Equus caballus) was examined in four horses. Unlike that of most species except for the rabbit, the submucous glands of the horse contain two distinct cell types, serous and mucous. These cells are described.
[The deciduous hoof capsule (Capsula ungulae decidua) of the equine fetus and newborn foal]. The term Eponychium is used to describe the deciduous hoof capsule in veterinary-medical and embryological literature. In other aspects of veterinary medicine, the term is generally reserved for the perioplic corium of the permanent hoof. In order to clarify this double usage, the structure and origin of the hoof epidermis from 10 equine fetus at different stages of development and 4 newborn foals were investigated and described using light microscopical techniques. Epidermal tubules and lamellae are already present in the non-cornified fetal hoof epidermis. These structures, along with the fo...
A combination histochemical stain for equine muscle. The purpose of this study was to find a combination histochemical staining technique for the evaluation of equine skeletal muscle that is reliable and effective, while offering a substantial reduction in the labor and cost involved with currently used individual histochemical methods. Several combinations under varying conditions of pH were studied. The most uniform results were obtained using an acid preincubation step at an optimal pH of 4.2 followed by reduced nicotinamide adenine dinucleotide-tetrazolium reductase (NADH-TR) and the remainder of the acid-ATPase procedure.
Preferential denervation of the adductor muscles of the equine larynx. I: Muscle pathology. The laryngeal muscles of 18 horses were examined histologically. The neurogenic changes found in each muscle were scored by four reviewers and the results evaluated statistically. Fifteen of these horses had endoscopic evidence of abnormal laryngeal function, three of which were defined as having adductor paralysis. Measurement of muscle fibre area in two horses with idiopathic laryngeal hemiplegia (ILH) was performed. In the quantitative study of neurogenic change, the adductor muscles were more significantly affected than the abductor muscle. This was also true in the clinical cases of ILH w...
Morphologic study of repair of induced osteochondral defects of the distal portion of the radial carpal bone in horses by use of glued periosteal autografts [corrected]. The use of periosteal autografts to resurface osteochondral defects was investigated in 10 horses (2 to 3 years old), and the repair tissue was characterized morphologically. Middle carpal joint arthrotomies were made, and osteochondral defects were induced bilaterally on the distal articular surface of each radial carpal bone. Each defect measured approximately 1 cm2 and extended 3 mm into the subchondral bone plate. Residual subchondral bone plate of control and principal defects was perforated by drilling. A sterile fibrin adhesive was made by mixing a fibrinogen component and a thrombin co...
Equine cutaneous mastocytoma: morphology, biological behaviour and evolution of the lesion. Thirty equine cutaneous mastocytomas were examined histologically and two were studied ultrastructurally. Lesions were characterized by distinct sheets of well-differentiated mast cells with variable degrees of eosinophil infiltration, collagen degeneration, necrosis, granulomatous inflammation and fibrosis. Twenty-two of 25 growths did not recur for up to 6 years after surgical excision, two recurred at the surgical site and one spontaneously regressed less than 3 months after obtaining a biopsy sample. Equine cutaneous mastocytoma is a benign proliferative lesion which seldom recurs after ex...
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.
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 ...
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 ...
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...
