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Topic:Clinical Pathology
Clinical pathology in horses involves the study and analysis of biological samples to diagnose and monitor diseases and health conditions. This discipline encompasses various laboratory tests and procedures that assess the physiological and biochemical status of equines. Common analyses include hematology, biochemistry, urinalysis, and cytology, each providing insights into different aspects of equine health. Hematology evaluates blood components, such as red and white blood cells and platelets, to identify conditions like anemia or infection. Biochemistry tests measure enzymes, electrolytes, and metabolites to assess organ function and metabolic status. Urinalysis examines urine samples for indicators of renal function and systemic diseases. Cytology involves the microscopic examination of cells from tissues or fluids to detect abnormalities. This page aggregates peer-reviewed research studies and scholarly articles that explore the methodologies, applications, and diagnostic value of clinical pathology in equine medicine.
Pharmacokinetics and clinical utility of sodium bromide (NaBr) as an estimator of extracellular fluid volume in horses. The purpose of this study was to describe the pharmacokinetics of bromide in horses and to evaluate the corrected bromide space as an indicator of extracellular fluid volume (ECFV) in horses after the administration of a single dose of bromide by intravenous infusion. Sodium bromide (30 mg/kg of body weight, IV) was administered to 6 clinically healthy mares over a period of 3 minutes. Blood samples were collected before infusion and at intervals between 0.5 hours and 53 days after infusion. Mean elimination half-life (harmonic mean) was 126 hours (5.2 days), clearance was 1.4 +/- 0.09 mL/(kg ...
Quantitative electromyographic examination in myogenic disorders of 6 horses. Electromyographic needle examination (EMG), including the semiautomatic quantitative analysis of motor unit action potential (MUAP), is an important diagnostic tool for myopathy in humans. The diagnostic possibilities of this technique have not been fully explored in horses; however, recent studies have shown that MUAP analysis can be performed in conscious horses. To determine the diagnostic possibilities of EMG in horses, we compared the EMG results of the subclavian muscle, the triceps, and the lateral vastus muscle in 6 equine patients thought to have myogenic disorders with those in 7 nor...
Gastric ulcers in standardbred racehorses: prevalence, lesion description, and risk factors. This study was performed to estimate the prevalence of gastric ulcers in Standardbred racehorses, to describe the lesion score and location, and to identify potential risk factors. Two hundred seventy-five (275) Standardbred horses from 5 training centers and 2 racetracks in Quebec, Canada, were studied. Historical data for the 2 months before examination were recorded for each horse, and the presence of gastric ulcers was determined by gastroscopy. A previously reported scoring system that used grades 0-3 for gastric lesions was used. Overall, 121 horses (44.0%; 95% CI, 38.1-50.1%) had gastri...
Idiopathic systemic granulomatous disease with encephalitis in a horse. A 14-year-old standardbred mare with clinically suspected acute bronchitis was killed because of rapidly progressing central nervous disturbances. Necropsy revealed systemic granulomatous inflammation and vasculitis involving the lungs, thoracic lymph nodes, ribs, and liver. In the cerebrum there was a severe subacute bilateral encephalitis and malacia predominately affecting the white matter, and vasculitis with perivascular infiltration of lymphocytes, macrophages, and giant cells. A causative infectious agent could not be detected by Ziehl-Neelsen, Grocott, or Giemsa stains, by periodic aci...
Pharmacokinetics and pharmacodynamics of clemastine in healthy horses. Clemastine is an H1 antagonist used in certain allergic disorders in humans and tentatively also in horses, although the pharmacology of the drug in this species has not yet been investigated. In the present study we determined basic pharmacokinetic parameters and compared the effect of the drug measured as inhibition of histamine-induced cutaneous wheal formation in six horses. The most prominent feature of drug disposition after intravenous dose of 50 microg/kg bw was a very rapid initial decline in plasma concentration, followed by a terminal phase with a half-life of 5.4 h. The volume of d...
Overview of suspected adverse reactions to veterinary medicinal products reported in South Africa (March 2001 – February 2002). An overview of reports of suspected adverse drug reactions received by the Veterinary Pharmacovigilance and Medicines Information Centre during the period March 2001 to February 2002 is given. A total of 77 reports were received. The majority of reports involved suspected adverse reactions that occurred in dogs and cats. Most products implicated in the reports were Stock Remedies. The products were predominantly administered either by veterinarians or trained paraveterinary professionals. Although the majority of reports were received from veterinary pharmaceutical companies, the proportion of...
Use of volumetric capnography to identify pulmonary dysfunction in horses with and without clinically apparent recurrent airway obstruction. To investigate whether volumetric capnography indices could be used to differentiate between horses without recurrent airway obstruction (RAO) and horses with RAO that were in clinical remission or that had clinically apparent RAO. Methods: 70 adult Swiss Warmblood horses (20 used for pleasure riding and 50 used for dressage or show jumping). Methods: Horses were allocated to 4 groups on the basis of history, clinical signs, results of endoscopy, and cytologic findings (group 1, 21 healthy horses; group 2, 22 horses with RAO that were in remission; group 3, 16 horses with mild RAO; group 4, 11...
Evaluation of systemic immunologic hyperreactivity after intradermal testing in horses with chronic laminitis. To determine whether systemic immunologic hyperreactivity exists in horses with chronic laminitis, compared with responses for nonlaminitic horses. Methods: 7 nonlaminitic horses and 7 CL horses. Methods: In experiment 1, intradermal testing (IDT) was performed on 7 nonlaminitic and 7 CL horses to evaluate the response to a combination of 70 allergens at 15 and 30 minutes and 4 and 24 hours after injection. Three nonlaminitic and 3 CL horses used in experiment 1 were used in experiment 2 to determine whether histologic differences existed between the 2 groups. The H&E-stained tissue sectio...
Expression of the ether-a-go-go (ERG) potassium channel in smooth muscle of the equine gastrointestinal tract and influence on activity of jejunal smooth muscle. To determine whether ether-a-go-go (ERG) potassium channels are expressed in equine gastrointestinal smooth muscle, whether ERG channel antagonists affect jejunal muscle contraction in vitro, and whether plasma cisapride concentrations in horses administered treatment for postoperative ileus (POI) are consistent with ERG channels as drug targets. Methods: Samples of intestinal smooth muscle obtained from 8 horses free of gastrointestinal tract disease and plasma samples obtained from 3 horses administered cisapride for treatment of POI. Methods: Membranes were prepared from the seromuscular la...
Equine immune-mediated hemolytic anemia associated with Clostridium perfringens infection. Previous studies have suggested an association between equine immune-mediated hemolytic anemia and clostridial infections or neck abscesses. Objective: The purpose of this report was to describe and characterize the hematologic abnormalities in a horse with Clostridium-associated immune-mediated hemolytic anemia. We also retrospectively evaluated hematologic abnormalities in 8 horses with clostridial myositis or subcutaneous emphysema. Methods: A 7-year-old Foreign Warm-Blood gelding was evaluated for anemia and a cervical abscess. CBCs and reticulocyte counts were obtained using an Advia 120 ...
[Clinical treatment of equestrian injuries in Groningen, 1990-1998: serious long-term effects]. To determine whether equestrian injuries result in long-term residual symptoms and to establish the risk factors for these outcomes. Methods: Retrospective, descriptive. Methods: A total of 88 patients older than 17 years of age who had been admitted to the Department of Surgery, University Hospital Groningen during the period 1990-1998 because of an equestrian injury were included in the study. After an average period of five years an inventory was made using the Sickness Impact Profile 68 (SIP68), if absenteeism from work or sport and disabilities or handicaps were experienced. Following thi...
Inhibition of collagenase breakdown of equine corneas by tetanus antitoxin, equine serum and acetylcysteine. To determine whether tetanus antitoxin, equine serum, and acetylcysteine, which are currently used in the treatment of equine corneal ulcer, inhibit the digestion of equine corneal collagen when exposed to collagenase in vitro. Methods: Corneas from 40 adult horses. Methods: Sections of equine corneas were incubated with saline, a solution of bacterial collagenase in saline, bacterial collagenase in saline plus equine tetanus antitoxin, bacterial collagenase in saline plus equine serum, or bacterial collagenase in saline plus acetylcysteine. Each one of the collagenase inhibitors was tested at...
Flash electroretinography in standing horses using the DTL microfiber electrode. The goal of our study was the evaluation of a practical method for the recording of flash electroretinograms (ERGs) in sedated, standing horses with the DTL microfiber electrode. Methods: The horses were sedated intravenously with detomidine hydrochloride (0.015 mg/kg). The pupil was dilated and the auriculopalpebral nerve was blocked. The ERGs were recorded with the active electrode on the cornea (DTL), the reference electrode near the lateral canthus, and the ground electrode over the occipital bone. The light intensities of the white strobe light were 0.03 cd x s/m2 (scotopic) and 3 cd x s/...
Ameloblastic carcinoma in a horse. The clinical, gross morphological, histological and immunohistochemical characteristics of an ameloblastic carcinoma in a 30-year-old Quarter Horse mare are reported. This tumour was fast growing, locally invasive and destructive. Histologically, it showed an infiltrative pattern of large islands, broad sheets and, at the periphery, small cords of moderately pleomorphic round, oval to spindle-shaped cells. Immunohistochemical evaluation revealed positive labelling for vimentin, cytokeratin 5/6 and cytokeratin 14. In the oral cavity of human beings, this immunolabelling pattern is unique for th...
Hepatic biliary adenofibroma: a hitherto unrecognized tumor in equines. Report of a case. Hepatic biliary cystadenoma is a well-delineated neoplasm in some domestic animals, especially in cats, but it has not been reported in equines. We report on a case of hepatic biliary tumor, incidentally found in a 10-year-old horse, with gross and microscopic features similar to those observed in biliary adenofibroma of humans. The tumor presented as a solid mass measuring 16 cm in diameter and histologically was composed of complex tubulocystic biliary components embedded in an abundant fibrotic stroma. We regarded this tumor as a morphological variant of biliary cystadenoma of domestic anim...
Invasive ductal carcinoma of the mammary gland in a mare. A 21-year-old thoroughbred mare had a 35 x 14 x 10 cm mass involving the mammary gland. Metastases were found in the kidneys, lungs, skeletal muscles, and regional lymph nodes. Histopathologic examination of the tumor revealed a ductal solid carcinoma with extensive intraductal and intralobular involvement and focal infiltration of the adjacent stroma. The intralobular neoplasms were divided into irregularly shaped islands and sheets of polygonal and spindle-shaped epithelial cells by thick or thin fibrous connective tissue bundles. The neoplastic cells had a small or moderate amount of cytopl...
Camelid mucoutaneous fibropapillomas: clinicopathologic findings and association with papillomavirus. Five camelid mucocutaneous fibropapillomas with histologic features similar to equine sarcoids were diagnosed. They were characterized by a dermal fibroblastic proliferation and overlying, often ulcerated hyperplastic epidermis with thin rete pegs extending down into the dermis. Two of the tumors came from llamas and three from alpacas. Four of the animals were 6-year-old females. The fifth was a 6-year-old castrated male. The fibropapillomas were located on the nose, lip, and cheeks. One of the llama tumors waxed and waned before surgery and recurred and spread after surgery. None of the othe...
Alkaline phosphatase in stallion semen: characterization and clinical applications. Significant amounts of alkaline phosphatase (AP) activity have been found in semen plasma from numerous species. In species in which the majority of semen plasma AP (SPAP) activity originates from the epididymis and testicle, SPAP activity can be used clinically as a marker to differentiate testicular origin azoospermia or oligospermia from ejaculatory failure. Information on SPAP activity in stallions to date has been limited. In this study, a standard clinical chemistry analyzer was used to determine AP activity in pre-ejaculatory fluid and ejaculates from groups of normal stallions. Additio...
UV measurements in microplates suitable for high-throughput protein determination. An UV spectrophotometric method for protein determination using microplates is described. Using the SPECTRAmax PLUS reader, the UVStar 96- and 384-well microplates and a 96 or 384 parallel channel liquid handling technique, large-scale determinations can be performed with intraassay precision better than 3% CV (coefficient of variation) in the range from 1 to 8000 microg of protein/ml, measuring at 205, 215, and 280 nm and using different volume-dependent light-path lengths. Since the absorbance coefficient at 205 nm is found to be 30 ml/(mgxcm) for eight different proteins with a CV of 5.6% o...
Hysteresis and calcium set-point for the calcium parathyroid hormone relationship in healthy horses. Abnormalities in calcium (Ca(2+)) homeostasis are reported in horses with several pathological conditions; however, there is little information on Ca(2+) regulation in horses. The objectives of the present study were to determine the Ca(2+) set-point in healthy horses, to determine whether the Ca(2+)/parathyroid hormone (PTH) response curves were characterized by hysteresis, and to determine if the order of experimentally induced hypocalcemia or hypercalcemia had an effect on PTH secretion. The Ca(2+) set-point and hysteresis were determined in 12 healthy horses by infusing Na(2)EDTA and calci...
Equine amplification and virulence of subtype IE Venezuelan equine encephalitis viruses isolated during the 1993 and 1996 Mexican epizootics. To assess the role of horses as amplification hosts during the 1993 and 1996 Mexican Venezuelan equine encephalitis (VEE) epizootics, we subcutaneously infected 10 horses by using four different equine isolates. Most horses showed little or no disease and low or nonexistent viremia. Neurologic disease developed in only 1 horse, and brain histopathologic examination showed meningeal lymphocytic infiltration, perivascular cuffing, and focal encephalitis. Three animals showed mild meningoencephalitis without clinical disease. Viral RNA was detected in the brain of several animals 12-14 days after...
Effect of aerosolized albuterol sulfate on resting energy expenditure determined by use of open-flow indirect calorimetry in horses with recurrent airway obstruction. To evaluate effects of sedation on stability of resistance of the respiratory system (RRS) and measures of resting energy expenditure (REE) by use of open-flow indirect calorimetry (IC) and treatment with aerosolized albuterol on REE in horses with recurrent airway obstruction (RAO). Methods: 9 clinically normal horses and 8 horses with RAO. Methods: In phase 1, RRS was measured by using forced oscillometry (FOT) in 5 clinically normal horses before and after sedation with xylazine. In phase 2, REE was measured in 4 clinically normal horses between 20 and 25 minutes and again 35 to 40 minutes ...
Interactions of morphine and isoflurane in horses. To quantitate dose- and time-related magnitudes of interactive effects of morphine (MOR) and isoflurane (ISO) in horses and to characterize pharmacokinetics of MOR in plasma and the ventilatory response to MOR during administration of ISO. Methods: 6 adult horses. Methods: Horses were anesthetized 3 times to determine the minimum alveolar concentration (MAC) of ISO in O2 and then to characterize the change in anesthetic requirement as defined by the alteration in ISO MAC following IV administration of saline (0.9% NaCl) solution and 2 doses of MOR (low dose, 0.25 mg/kg; high dose, 2.0 mg/kg). ...
Malignant Sertoli cell tumor in the retained abdominal testis of a unilaterally cryptorchid horse. A 13-year-old Morgan gelding was evaluated because of a mass in the caudal region of the abdomen. The horse had been presumed to be a gelding, but necropsy findings revealed a retained testis in the right retroperitoneal space. Histologically, the retained testis contained neoplastic cells; metastases were identified in the liver, spleen, lungs, and sublumbar lymph nodes. Immunohistochemical examination of the testis and metastatic tissues confirmed the diagnosis of malignant Sertoli cell tumor. Testicular neoplasms are infrequently reported in stallions. Seminomas are most commonly reported, ...
Stress fractures of the tibia and humerus in Thoroughbred racehorses: 99 cases (1992-2000). To determine clinical characteristics of and outcome in Thoroughbred racehorses with tibial or humeral stress fractures. Methods: Retrospective study. Methods: 99 Thoroughbreds with tibial or humeral stress fractures. Methods: Information obtained from the medical records included history, signalment, and clinical, radiographic, and scintigraphic findings. Outcome was determined by interviewing trainers, performing follow-up examinations, and analyzing race records. Results: Seventy-four tibial stress fractures were identified in 61 Thoroughbreds, and 48 humeral stress fractures were identifie...
Allisonella histaminiformans gen. nov., sp. nov. A novel bacterium that produces histamine, utilizes histidine as its sole energy source, and could play a role in bovine and equine laminitis. When cattle and horses are fed large amounts of grain, histamine can accumulate in the gastrointestinal tract, and this accumulation can cause an acute inflammation of the hooves (laminitis). When ruminal fluid from dairy cattle fed grain supplements was serially diluted in anaerobic MRS medium containing histidine (50 mM), histamine was detected at dilutions as high as 10(-7). The histidine enrichments were then transferred successively in an anaerobic, carbonate-based medium (50 mM histidine) without glucose. The histamine producing bacteria could not be isolated from the rumens of cattle fe...
