Omneity® Pellets
All-In-One Vitamin & Mineral Pellet
Topic:Histopathology
Histopathology in horses involves the microscopic examination of tissue samples to study the manifestations of disease. This field provides insights into the structural and cellular changes that occur in equine tissues as a result of various pathological conditions. Common applications of histopathology in equine medicine include the diagnosis of neoplastic, inflammatory, and degenerative diseases. Techniques such as tissue staining and immunohistochemistry are employed to identify specific cellular components and pathological markers. This page aggregates peer-reviewed research studies and scholarly articles that explore the methodologies, findings, and implications of histopathological investigations in equine health.
Immunoconversion against Sarcocystis neurona in normal and dexamethasone-treated horses challenged with S. neurona sporocysts. Equine protozoal myeloencephalitis is a common neurologic disease of horses in the Americas usually caused by Sarcocystis neurona. To date, the disease has not been induced in horses using characterized sporocysts from Didelphis virginiana, the definitive host. S. neurona sporocysts from 15 naturally infected opossums were fed to horses seronegative for antibodies against S. neurona. Eight horses were given 5x10(5) sporocysts daily for 7 days. Horses were examined for abnormal clinical signs, and blood and cerebrospinal fluid were harvested at intervals for 90 days after the first day of chall...
Immunohistochemical analysis of equine pulmonary granular cell tumours. Histopathological and immunohistochemical examinations were made on four female horses aged 9-12 years with pulmonary granular cell tumours (GCTs). The tumours, which were multiple, of varying size, firm and off-white in colour, surrounded the bronchi and bronchioles. Metastatic lesions were not detected. The tumour cells had abundant eosinophilic cytoplasm filled with prominent coarse eosinophilic granules. Immunohistochemically, these tumour cells reacted uniformly with vimentin and S100 antibodies. Most were immunolabelled by antibodies against glial fibrillary acidic protein (GFAP), myelin...
Effects of anti-inflammatory drugs on lipopolysaccharide-challenged and -unchallenged equine synovial explants. To evaluate the effects of anti-inflammatory drugs on lipopolysaccharide (LPS)-challenged and -unchallenged equine synovial membrane in terms of production of prostaglandin E2 (PGE2) and hyaluronan, viability, and histomorphologic characteristics. Methods: Synovial membranes were collected from the carpal, tarsocrural, and femoropatellar joints of 6 adult horses. Methods: Synovial membranes from each horse were minced and pooled and explants were treated with one of the following: no drug (control), drug, LPS alone, or LPS and drug. Treatment drugs were phenylbutazone (PBZ), flunixin meglumine...
Equine lymphocytic-plasmacytic enterocolitis: a retrospective study of 14 cases. Lymphocytic-plasmacytic enteritis (LPE) is a morphological diagnosis given to a type of infiltrative intestinal disease classified within the complex of idiopathic inflammatory bowel disease (IBD). The purpose of this retrospective study was to describe the details of breed, age and sex, clinical and clinicopathological findings and outcome of horses diagnosed with LPE. Data were reported from 14 horses that had a histopathological diagnosis of LPE; the median age was 12 years, and there was no breed or sex predilection. Common clinical signs were weight loss (100%), diarrhoea (50%) and lethar...
Fatal nonneurological EHV-1 infection in a yearling filly. A case of fatal nonneurological equine herpesvirus 1 (EHV-1) infection in a yearling filly is described. Gross lesions included extensive pulmonary edema, prominent laryngeal lymphoid follicles, and congestion and edema of the dorsal third ventricle choroid plexus. Histologically, there was vasculitis, hemorrhage, and edema in the lungs and dorsal third ventricle choroid plexus as well as mild intestinal crypt necrosis with occasional intranuclear inclusion bodies. The perivascular and vascular inflammatory infiltrates were comprised mainly of T lymphocytes and macrophages. EHV-1 antigen was i...
Serum markers of lamellar basement membrane degradation and lamellar histopathological changes in horses affected with laminitis. In order better to evaluate the extent to which degradation of the lamellar basement membrane (LBM) by matrix metalloproteinases (MMP) occurs in equine laminitis, we determined the concentration of type IV collagen and laminin in normal and laminitic horses, using specific immunoassays. Blood samples were obtained from both the jugular and the cephalic veins of horses (n = 10) before and after the induction of acute alimentary laminitis by carbohydrate overload. Jugular and cephalic venous blood samples were also obtained from horses affected with naturally occurring laminitis (n = 16) and non...
Early changes in the distal intertarsal joint of Dutch Warmblood foals and the influence of exercise on bone density in the third tarsal bone. It was hypothesised that imposition of different exercise levels at a young age would lead to differences in bone density in the third tarsal bone and to difference in the prevalence of pathological lesions that might contribute to the development of bone spavin later in life. Furthermore, based on earlier literature, it was hypothesised that such lesions could be classified as a manifestation of osteochondrosis. Changes in bone density in the third tarsal bone and early pathological changes in the articular cartilage of the distal intertarsal joint were studied in the offspring of sires with ...
Determination of synovial fluid and serum concentrations, and morphologic effects of intraarticular ceftiofur sodium in horses. To determine the serum and synovial fluid concentrations of ceftiofur sodium after intraarticular (IA) and intravenous (IV) administration and to evaluate the morphologic changes after intraarticular ceftiofur sodium administration. Methods: Strip plot design for the ceftiofur sodium serum and synovial fluid concentrations and a split plot design for the cytologic and histopathologic evaluation. Methods: Six healthy adult horses without lameness. Methods: Stage 1: Ceftiofur sodium (2.2 mg/kg) was administered IV. Stage 2: 150 mg (3 mL) of ceftiofur sodium (pHavg 6.57) was administered IA into ...
Use of an extracorporeal circuit to evaluate effects of ischemia and reperfusion of the equine large colon. To determine efficacy of an extracorporeal circuit to maintain a segment of equine large colon for 3.5 hours and to evaluate the effect of low arterial flow on histologic and metabolic variables. Methods: Segments of large colon from 15 healthy adult horses. Methods: The pelvic flexure was surgically removed and maintained in an isolated circuit. In the control group, tissue was evaluated for 3.5 hours, whereas in the low-flow group, arterial flow was reduced to 20% of baseline for 40 minutes followed by 2 hours of reperfusion. Various metabolic and hemodynamic variables were evaluated at 30-m...
Miscellaneous. This section includes clinical conditions which have unique characteristics which make them unsuitable for inclusion in the first six sections. The clinical description, aetiology and histopathologic findings of the unusual ear lesion, aural plaques, are described. Dermatoses complicated by, or caused by, photosensitivity are discussed in regards to their aetiology and pathogenesis as well as clinical features. The suggestion that photosensitization plays a role in the development of the lesions seen in pastern leukocytoclastic vasculitis is made. This section ends with an in depth discussion ...
Medical treatment of cholangiohepatitis and cholelithiasis in mature horses: 9 cases (1991-1998). The medical approach to treatment of cholangiohepatitis and cholelithiasis in 9 horses is described. Seven horses were treated successfully and returned to normal use, with a minimum follow-up period of 12 months. Long-term antimicrobial therapy was believed to be critical in those cases that survived, with a median treatment duration of 51 days (range 17-124 days). Treatment failure was associated with severe periportal and bridging hepatic fibrosis from biopsy material obtained at admission in 2 horses, one of whom also presented with hyperammonaemic hepatic encephalopathy. Transabdominal ul...
Detection of DNA in ancient bones using histochemical methods. We describe histochemical techniques for detecting DNA within the osteocytic lacunae of ancient bones. The bones examined were fragments of femurs from two human individuals found in the Pompeian C. I. Polybius house and fragments of metacarpals from two horses (Equus sp.) found in the Pompeian "Casti Amanti" house. Both buildings were buried by the 79 A. D. Vesuvius eruption. Fragments of femurs from a modern horse, a modern swine and a modern amphibian also were studied as controls. Some bone sections were stained with two different DNA-specific fluorochromes, 4'-'6-diamidino-2-phenylindole ...
Lymphangiosarcoma in a horse. A 15-year-old Dutch Warmblood mare presented with respiratory distress and anorexia. Clinical examination revealed liquothorax and an abdominal mass. At necropsy, an infiltrating tumour was found in the visceral trunk, continuing through the diaphragm into the mediastinum. Histopathology, immunohistochemistry and electronmicroscopy showed empty channels lined by atypical endothelial cells, and neoplastic cells in a disorganized pattern, consistent with the diagnosis of a lymphangiosarcoma.
The study of cutaneous melanomas in Camargue-type gray-skinned horses (1): clinical-pathological characterization. The clinical and pathological characteristics of cutaneous melanomas occurring in Camargue-type gray-skinned horses are reported. Examination of 83 tumor-bearing horses revealed that the tumors occurred most frequently underneath the tail (93.9%) and at high rates in the peri-anal region (43.0%), the lips (33.0%), and the eyelids (24.0%), but rarely in the vulva (3.8%). Tumorous lesions were characterized by the presence of either hemispheric nodules or large infiltrated plaques, or their combinations. Microscopic examination indicated that tumorous lesions were composed mostly of melanocytes ...
Functional and histopathological evidence of cardiac parasympathetic dysautonomia in equine grass sickness. The parasympathetic terminal cardiac ganglia were examined in three normal horses and in five horses with grass sickness. Histopathological changes, consistent with those observed in other ganglia of horses with grass sickness, were identified in the terminal cardiac ganglia of the affected horses. A functional analysis of cardiac autonomic control by time domain analysis (TDA) of heart rate variability was applied to eight horses with grass sickness, and double-paired to 16 normal horses on the basis of their age, sex and breed, and the time of day at which the electrocardiographs were obtain...
Listeria monocytogenes septicemia in a Thoroughbred foal. Listeria monocytogenes septicemia was diagnosed in a 6-day-old Thoroughbred foal. Primary clinical signs included fever, depression, diarrhea, and respiratory distress. Hematologic abnormalities included leukopenia, neutropenia, degenerative left shift, and hyperfibrinogenemia. Clinical chemistry and blood gas abnormalities included metabolic acidosis, hypoxemia, hypocapnia, hypoglycemia, and hyponatremia. Despite aggressive therapeutic intervention and intensive care, the foal died within 12 hours of admission. A postmortem examination was performed, and the primary gross lesion was bilateral...
Staining abnormalities of dermal collagen in eosinophil- or neutrophil-rich inflammatory dermatoses of horses and cats as demonstrated with Masson’s trichrome stain. A retrospective study was performed on skin biopsy specimens from horses and cats having eosinophilic granulomas with 'collagen degeneration', eosinophilic skin diseases without 'collagen degeneration' and pyogranulomas without 'collagen degeneration'. Neither the appearance of collagen fibres nor the dominant polymorphonuclear cells, as seen in H & E-stained sections, were predictive of Masson's trichrome findings. Hence, a Masson's trichrome staining abnormality of collagen fibres was no more likely to be present in lesions with 'collagen degeneration' than in those lesions without 'coll...
Correlation of clinical score, intrapleural pressure, cytologic findings of bronchoalveolar fluid, and histopathologic lesions of pulmonary tissue in horses with summer pasture-associated obstructive pulmonary disease. To correlate clinical score, intrapleural pressure, cytologic findings of bronchoalveolar lavage fluid (BALF), and histologic lesions of pulmonary tissue in horses affected with summer pasture-associated obstructive pulmonary disease (SPAOPD). Methods: 8 adult horses affected with SPAOPD and 6 adult horses without evidence of respiratory tract disease. Methods: Clinical score, change in intrapleural pressure (deltaPpl) during tidal breathing, results of cytologic examination and bacteriologic culture of BALF, and results of histologic examination of pulmonary parenchyma were evaluated. Results...
Exertional rhabdomyolysis in quarter horses and thoroughbreds: one syndrome, multiple aetiologies. The purpose of this study was to determine if chronic exertional rhabdomyolysis (ER) in Quarter Horses and Thoroughbreds represents one or several distinct myopathies. Eighteen Quarter Horses and 18 Thoroughbreds with ER were selected from cases presented to the Veterinary Hospital on the basis of a history of ER, assessment of muscle histopathology, and serum CK activity before and 4 h post exercise. In addition, 2 of 3 of the following parameters were evaluated: muscle glycogen concentrations, thyroid hormones (T3, T4), fractional excretion (FE) of sodium, potassium and chloride. The CK resp...
Experimental infection of ponies with Borrelia burgdorferi by exposure to Ixodid ticks. Seven specific-pathogen-free (SPF) ponies, 1-5 years old, were exposed to Borrelia burgdorferi-infected adult ticks while being treated with dexamethasone over 5 consecutive days. One SPF pony (pony No. 178) was first exposed to laboratory-reared nymphs without B. burgdorferi infection and 3 weeks later was exposed to B. burgdorferi-infected adult ticks with concurrent dexamethasone treatment for 5 consecutive days. Four uninfected ponies treated with dexamethasone, exposed to laboratory-reared ticks without B. burgdorferi infection served as uninfected controls. Clinical signs, bacteriologic ...
Small intestinal adenomatous polyposis resulting in protein-losing enteropathy in a horse. A 4-year-old Quarter Horse gelding was presented with a history of weight loss of 6 months duration, along with extensive ventral subcutaneous edema. Clinicopathologic findings included a markedly low serum total protein (2.9 g/dl) and a low packed cell volume (24%). The mucosal surface of the distal jejunum and entire ileum were carpeted with numerous polypoid, papillary, and glandular masses comprised of pseudostratified tall columnar cells and large numbers of interspersed goblet cells. Neoplastic change was diffuse throughout the mucosa of each mass, but abrupt demarcation occurred between...
Functional disturbances in the endometrium of barren mares: a histological and immunohistological study. Different types of endometrial maldifferentiation were investigated by histopathological (haematoxylin-eosin (HE), periodic acid Schiff-alcian blue and picro-sirius red staining) and immunohistological (oestrogen and progesterone receptors, Ki-67 antigen, intermediate filaments and laminin) analysis of endometrial biopsy specimens from mares (n=34), most of which had been barren for at least 1 year. Two major features were observed: (i) unequal differentiation, in which two functional stages are visible within a single biopsy sample: areas which are differentiated in accordance with the stage ...
Injection site eosinophilic granulomas and collagenolysis in 3 horses. Three horses were presented with a history of having developed raised cutaneous nodules, within 24-48 hours, in areas of previous injections using standard silicone-coated hypodermic needles. Skin biopsies were taken from a selected cutaneous nodule from all horses for histopathologic evaluation. Histologically, the nodules were consistent with a diagnosis of equine eosinophilic granuloma. A hypersensitivity reaction to the silicone, or another component of the coating formulation, was hypothesized to be responsible for these lesions. Two horses were experimentally injected using both coated a...
Characterization of T-lymphocytes in the anterior uvea of eyes with chronic equine recurrent uveitis. Equine recurrent uveitis (ERU), a chronic, recurrent inflammation primarily of the anterior uveal tract, is the most common cause of blindness in horses. Recently, T-lymphocytes have been found to be the most numerous cell type to infiltrate the anterior uveal of horses with ERU. In the present study, we characterized the T-lymphocyte population in the anterior uveal tract of eyes of horses with chronic ERU by evaluating the microscopic appearance (histopathologic features), the T-lymphocyte subsets, and the relative levels and amounts of T-lymphocyte cytokine mRNA in the anterior uvea. Seven ...
Comparison of the pathogenesis of acute equine herpesvirus 1 (EHV-1) infection in the horse and the mouse model: a review. The mouse models of the respiratory and abortion forms of equine herpesvirus 1 (EHV-1) infection have been used to investigate the vaccine potential of various EHV-1 immunogens, the effect of antiviral agents on EHV-1 infection and the pathogenicity of EHV-1 strain variants and deletion or insertional mutants. This review examines the similarities and differences in the pathogenesis of primary EHV-1 infection in the natural host, the horse, and in the mouse by comparing tissue tropism, clinical signs of infection, the effects of EHV-1 on pregnancy, haematological changes following infection, v...
Inter-relationship between Gasterophilus larvae and the horse’s gastric and duodenal wall with special reference to penetration. The degree of penetration into the stomach and duodenum of the horse by bot fly larvae, Gasterophilus intestinalis (De Geer) and G. nasalis (Linnaeus) (Diptera : Gasterophilidae) was evaluated. Evidence of larval perforation of the stomach or duodenum was not found on gross inspection. Palpation of the intact stomach and duodenum was not effective in establishing the existence of Gasterophilus larvae within the organs. Findings suggest that larvae of both species produce an ulcer of similar depth within the gastrointestinal wall. The ulcer depth produced by larvae did not correlate with the no...
Intramuscular desmoid tumor (musculoaponeurotic fibromatosis) in two horses. Intramuscular desmoid tumors (musculoaponeurotic fibromatosis) were discovered in two young adult horses. The tumor in one horse was in the lateral cervical musculature, and that in the second horse occurred in the pectoral musculature. Histopathologic features were similar in both horses and included proliferation of fibroblasts and cells expressing muscle actin (myofibroblasts), with extensive dissecting fibrosis within muscle. These features are similar to those of desmoid tumors in humans, particularly those also known as musculoaponeurotic fibromatosis. Dissection of these lesions reveale...
A congenital malformation of the maxilla of a horse. A 1-month-old male American Paint Horse was evaluated for a hard swelling on the right side of the maxillary region. On radiographs there was a large, expansile outpouching of the right maxillary bone between the second and third premolar teeth. Computed tomography further characterized the expansile lesion to have a soft tissue component and to originate in the region of a caudal maxillary tooth. Surgical reconstruction of the defect was unsuccessful and the animal was euthanetized. Based on failure to find histopathologic evidence of a neoplasm or cyst, the diagnosis was a congenital malform...
Chronic renal failure associated with nephrolithiasis, ureterolithiasis, and renal dysplasia in a 2-year-old quarter horse gelding. A 2-year-old quarter horse gelding presented for evaluation of polyuria and polydipsia. Azotemia was detected on serum chemistry profile. Small, misshapen, hyperechoic kidneys with decreased corticomedullary demarcation, hydronephrosis, and a right nephrolith were noted ultrasonographically. The diagnosis of end-stage kidney disease and dysplasia was made histopathologically using ultrasound-guided biopsy. Two ureteroliths were found in the right ureter via cystoscopy, and a nephrolith was seen in the right kidney at necropsy. Clinical, ultrasonographic, and pathologic features of equine uroli...
Histopathological findings in equine sinonasal disorders. Biopsies collected from 79 referred cases of equine sinonasal disease, including 27 horses with primary sinusitis, 10 with secondary dental sinusitis, 19 with sinus cysts, 11 with progressive ethmoid haematomata (PEH), 4 with false nostril epidermal inclusion cysts, 4 with sinonasal polyps, 3 with sinonasal mycosis and from 2 control animals were examined histologically. Observations were made on epithelial type and integrity, cellular inflammatory response, fibroplasia and presence of potential pathogens. Chronic inflammatory changes including mucosal thickening, ulceration and significant fi...
