Use of immunohistochemical methods for diagnosis of equine pythiosis

Excisional biopsy specimens were received from 8 horses with lesions suspected of being caused by Pythium sp. Pythium sp was isolated from all specimens. An indirect peroxidase technique was applied to formalin-fixed tissues from the biopsy material and there was distinct staining of hyphal cell walls in all specimens. Sections containing hyphae, other than those of Pythium sp, failed to stain. The indirect peroxidase technique could be used for confirmation of suspected cases of pythiosis.     

Cytology of diffuse mesothelioma in the thorax of a horse.

Examination of effusions from body cavities must include a search for neoplastic as well as inflammatory cells. Neoplastic cells found in the thorax are generally derived from adenocarcinomas or mesotheliomas. Mesotheliomas are relatively uncommon and the neoplastic cells found in effusions are difficult to differentiate from activated cells in inflammatory effusions. An ante-mortem diagnosis of mesothelioma was made in a mare on the basis of the large volume of fluid produced, the pleomorphic mesothelial cells, the polyp formation and the absence of PAS staining material after digestion of the cell impression with maltase diastase.     

Use of electromyography for the diagnosis of equine hyperkalemic periodic paresis.

The use of electromyography (EMG) as a diagnostic aid for equine hyperkalemic periodic paresis (EHPP) was investigated in seven affected and seven control horses. Affected horses were confirmed positive for EHPP either by elevated serum potassium concentration with clinical signs of myotonia, or by inducing hyperkalemia and clinical signs using oral potassium chloride challenge. All horses were asymptomatic at the time EMG was performed, using bipolar fine wire needle electrodes. The myopotentials were recorded on magnetic tape and displayed on paper charts for analysis. Insertional and resting activity were recorded from the right supraspinatus, triceps, extensor carpi radialis and gluteal muscles in standing horses. Myotonic discharges were seen in six of seven affected horses but not in any of the controls. All seven affected horses and two control horses had prolonged insertional activity. Five out of seven affected horses and one control horse displayed spontaneous motor unit discharges unrelated to recording electrode movement. Myoelectrical potentials containing closely timed muscle potentials, i.e. doublets, were found in all affected horses, with four of seven affected horses also showing triplets. These potentials were not observed in any of the controls. No obvious difference in activity was observed among the four muscle sites tested. It is concluded that EMG is a safe and useful tool for diagnosing EHPP in horses not currently displaying clinical signs. Myotonic discharges and doublets appear to be the most diagnostically significant electromyographic abnormalities in EHPP affected horses.     

Juvenile malignant mesothelioma in a dog

An 11-month-old male mixed breed dog was euthanized due to two months history of vomiting and anorexia. At necropsy, numerous, multifocal or coalescing, firm, protruding nodules, 5 to 40 mm in diameter were scattered throughout the mesentery and omentum. Histologically and immunohistochemically, the nodules were diagnosed as malignant mesothelioma. Metastasis to the regional mesenteric, mediastinal and tracheobronchial lymph nodes were observed.     

Mononuclear cell infiltration of the equine endometrium: immunohistochemical studies.

Endometrial sections from mares with varying degrees of mononuclear cell infiltration were examined for immunoglobulin (Ig)A-, IgM-, IgG(T)- and IgG(Fc)-containing cells, luminal and glandular epithelial cell Ig-staining and free interstitial Ig-staining, using a peroxidase anti-peroxidase technique. Mares with mild to moderate (Group 2) and mares with severe diffuse mononuclear cell infiltration, superimposed by acute endometritis (Group 3), had significantly higher numbers of Ig-containing cells than genitally-normal mares (Group 1). The differences between Groups 1 and 3 were significant for all four isotypes. In Groups 1 and 2, numbers of IgA-containing cells were significantly larger than numbers of IgM- and IgG(T)-containing cells. Generally, more glandular epithelial cells stained for IgA and IgM than for IgG(T) and IgG(Fc), and Ig-staining for all isotypes increased from Group 1 to Group 3. Free interstitial staining did not appear to differ among the three groups, but IgG(Fc)- and IgG(T)-staining generally was more intense than IgA- and IgM-staining. The efficiency of uterine defence in the mare does not seem to depend solely on humoral factors, and defects involving other components of the defence system may contribute to failure of the uterus to clear infection.     

Use of scintigraphy for diagnosis of equine paranasal sinus disorders

OBJECTIVES: To describe and analyze subjective and objective scintigraphic findings in horses with paranasal sinus disorders. ANIMALS: Horses with suspected disorders of the paranasal sinuses or cheek teeth (n = 48) and control horses (n = 30). METHODS: 99Technetium-methylenediphosphate (99Tc-MDP; 7500 MBq) was administered for scintigraphic examination of the skull. Abnormal patterns of increased radionuclide uptake (IRU) were identified and subjectively described. Scintigrams and radiographs were blindly assessed by 2 clinicians and the accuracy of the imaging modalities was compared. Objective analysis was performed by comparing regions of interest (ROI) drawn over areas of abnormal IRU to the equivalent area on the unaffected side using the Mann-Whitney test. An ROI ratio (affected:non-affected sides) was also calculated for each lesion. RESULTS: Twenty-eight horses were diagnosed with primary (15) or secondary (13) sinusitis. Nine primary sinusitis cases had focal area(s) of moderate or marked IRU in addition to a more diffuse uptake in the affected sinus(es). kappa was marginally higher for scintigraphic assessment of paranasal sinus disorders than for radiographic assessment. There were significant differences in mean counts/pixel in ROI drawn on the affected side compared with the non-affected side. There was considerable overlap between the magnitudes of ROI ratios found with many different disorders. CONCLUSIONS: Scintigraphy can be useful for differentiation of sinusitis of dental origin from other causes of sinusitis. Quantitative analysis of scintigrams is not reliable for identification of particular disorders. CLINICAL RELEVANCE: Focal areas of moderate or marked IRU may be observed with primary sinusitis. Careful 3-dimensional localization of the lesion, along with consideration of other clinical and diagnostic findings should be performed to prevent false-positive diagnoses of periapical infection in such instances.     

Use of cisplatin for control of metastatic malignant mesenchymoma and hypertrophic osteopathy in a dog

Cisplatin (cis-diammine-dichloroplatinum) treatment induced partial remission of pulmonary metastatic malignant mesenchymoma and nearly complete radiographic remission of hypertrophic osteopathy in a 14-year-old Beagle. Cisplatin was given once every 3 weeks. Clinical signs of hypertrophic osteopathy resolved one week after initiation of treatment. Partial remission of pulmonary metastases and partial radiographic remission of hypertrophic osteopathy was seen 6 weeks after initiation of treatment. Previous treatment of neoplasia-related hypertrophic osteopathy has consisted of removal of the initiating mass or vagotomy. In this case, appropriate chemotherapy was used to control clinical signs and progression of hypertrophic osteopathy.     

Use of contrast ultrasonography in the diagnosis of metastatic feline visceral haemangiosarcoma

A 12-year-old cat was presented for investigation of weight loss and inappetence. Radiography and conventional grey-scale ultrasonography showed a large mid-body splenic mass. Contrast enhanced ultrasonography of the liver demonstrated a hypoechoic left lateral lobe nodular mass during the peak and late portal-phases of liver enhancement. Histopathology of the splenic mass and hepatic nodular mass confirmed haemangiosarcoma. The use of ultrasound microbubble contrast media in the diagnosis of hepatic metastasis in the cat has not been previously reported in the cat.     

Use of an ELISA test in the eradication of an equine infectious anaemia focus

Summary An enzyme linked immunosorbent assay (ELISA) test and the classic agar gel immunodiffusion (AGID) test were used as diagnostic methods in the eradication of a focus of equine infectious anaemia from a herd of 86 horses. The ELISA test proved to be more sensitive, detecting positive animals earlier than the AGID test. A group of 16 animals positive only by ELISA also became positive to the AGID when retested one month later, except for 2 animals which showed clinical signs of the disease and died before retesting.

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El Uso De Una Prueba Elisa En La Erradicacion De Un Foco De Anemia Infecciosa Equina

Resumen La prubla ELISA (Enzyme Linked Immunosorbent Assay) y la pruebla clásico de imunodifusión en gel agar (IDGA) fueron utilizados como métodos de diagnóstico para eliminar un foco de Anemia Infecciosa Equina. La pruebla de ELISA fue más sensible, detectando los animales positivos antes que la pruebla de IDGA. Un grupo de animales positivos, que fueron detectados solamente por la pruebla de ELISA, fueron también detectados por la pruebla de IDGA en el reteste después de treinta dias. De los 16 animales de ese grupo, solamente 2 mostrarom signos clinicos de la enfermedad y murieron antes de la realización del reteste.

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L'utilisation Du Test Elisa Dans L'eradication D'un Foyer D'anemie Infectieuse Equine

Résumé Un test d'ELISA (Enzyme Linked Immunosorbent Assay) et un test cassique d'immunodiffusion en gel d'agar (IDGA) ont été utilisés comme méthodes de diagnostic de l'erradication d'un foyer d'Anémie Infectiuse Equine. Le test d'ELISA a été le plus sensible detectant animaux positifs plus tot que le test d'IDGA. Un groupe d'animaux positifs qui ont été detectés seulement par le test d'ELISA ont aussi été detectés par le test d'IDGA lors d'un nouveau test après trente jours. De ce groupe constituté par seize animaux, seulement deux ont montré des signes cliniques de la maladie et sort morts avant la réalisation du nouveau test.

     

Assessment of glycosaminoglycan concentration in equine synovial fluid as a marker of joint disease.

A modification of a colorimetric assay was used to determine synovial fluid total and individual sulphated-glycosaminoglycan concentration in various clinical presentations of joint disease in horses. Concentrations of synovial fluid and serum sulphated-glycosaminoglycan (GAG) were measured by the 1,9-dimethylmethylene blue (DMMB) dye assay in normal horses (n = 49), horses with acute (n = 26) or chronic (n = 27) joint disease (defined by clinical, radiographic, and clinicopathological parameters), and horses with cartilaginous lesions at diagnostic arthroscopy, but with normal radiographs and synovial fluid (n = 9). Horses with acute joint disease were subdivided into moderate acute (n = 21) and severe acute (n = 5) joint disease on the basis of synovial fluid analysis and clinical examination. Horses with chronic joint disease were subdivided into mild chronic (n = 9), moderate chronic (n = 10), and severe chronic (n = 8) joint disease on the basis of synovial fluid analysis, clinical examination, and radiographic findings. The concentrations of chondroitin sulphate (CS) and keratan sulphate (KS) were analyzed in each sample following sequential enzymatic digestion of the sample with chondroitinase or keratanase. In addition, the concentration of hyaluronate (HA) in each sample was determined by a colorimetric assay following digestion of the sample with microbial hyaluronidase.(ABSTRACT TRUNCATED AT 250 WORDS)     

Laboratory methods of equine pregnancy diagnosis.

Rectal examination is a reliable method of diagnosing pregnancy in the mare. Also, test kits are available for the simple quick detection of pregnant mare serum gonadotrophin. Nevertheless there is a considerable demand by practitioners for an independent laboratory service in equine pregnancy diagnosis, particularly during the gestational phase when placental gonadotrophin is concentrated in the blood. An initial attempt to provide a service by means of the agar gel diffusion test was disappointing and alternatives were sought. The primary requirements for an ideal alternative technique were defined as: accuracy, sensitivity, applicability to the optimum request period, elimination of subjective interpretation and a minimal inconclusive rate. Additional considerations included cost, practicality and test duration. The various tests available are summarised and their published accuracies are discussed. It was decided to reverse the current trend from biological to immunological techniques and to modify the test by which Cole and Hart announced the discovery of PMSG in 1930. The utero-ovarian response in the immature female mouse was quantified simply to produce a numerical result. The reason for this is explained, the method is described and its accuracy is evaluated. The primary requirements, defined above, were achieved.     

Toxic equine parkinsonism: an immunohistochemical study of 10 horses with nigropallidal encephalomalacia

Chronic ingestion of yellow star thistle (Centaurea solstitialis) or Russian knapweed (Acroptilon repens) causes nigropallidal encephalomalacia (NPE) in horses with an abrupt onset of neurologic signs characterized by dystonia of lips and tongue, inability to prehend food, depression, and locomotor deficits. The objectives of this study were to reexamine the pathologic alterations of NPE and to conduct an immunohistochemistry study using antibodies to tyrosine hydroxylase and α-synuclein, to determine whether NPE brains show histopathologic features resembling those in human Parkinson disease. Results confirm that the NPE lesions are located within the substantia nigra pars reticulata, sparing the cell bodies of the dopaminergic neurons in the substantia nigra pars compacta, and in the rostral portion of the globus pallidus, with partial disruption of dopaminergic (tyrosine hydroxylase-positive) fibers passing through the globus pallidus. No abnormal cytoplasmic inclusions like the Lewy bodies of human Parkinson disease were seen in these NPE brains. These findings indicate that equine NPE may serve as a large animal model of environmentally acquired toxic parkinsonism, with clinical phenotype directly attributable to lesions in globus pallidus and substantia nigra pars reticulata rather than to the destruction of dopaminergic neurons.     

Tools for the diagnosis of equine respiratory disorders.

Respiratory disorders are among the most common problems leading horse owners to seek veterinary attention. Accurate diagnosis of these conditions allows for proper treatment to be instituted, much to the benefit of the patient and satisfaction of the client. As an introduction to this issue on equine respiratory disorders, we review some of the tools that are available to equine veterinarians for the diagnosis of respiratory disorders. Physical and endoscopic examination, radiology, diagnostic ultrasound, techniques for sampling the respiratory tract, hematology, blood gas analysis, respiratory mechanics, and some modern diagnostic tools are briefly covered.