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Biomedical subjects

A Delahunta

Publications and source records attributed to A Delahunta.

7 recordsLinked to original sources

CNS hypomyelination in Rat Terrier dogs with congenital goiter and a mutation in the thyroid peroxidase gene.

Arrested physical development and neurologic abnormalities were identified in 3 of 5 Rat Terrier puppies at 9 weeks of age. Bilaterally firm symmetrical masses were palpated in the region of the thyroid glands. Low serum total (T4) and free thyroxine (FT4, by equilibrium dialysis) and markedly elevated thyroid stimulating hormone (TSH) concentrations supported the diagnosis of hypothyroidism. At necropsy, the thyroid gland was grossly enlarged and histologically exhibited severe, diffuse hyperplasia of the follicular epithelium. Gross examination of the central nervous system revealed a myelin deficiency, most evident in the corpus callosum. Regional distribution of hypomyelination was confirmed histologically, affecting the corpus callosum and, to a lesser degree, the corona radiata, the longitudinal fibers of the pons, the pyramids, and the lateral funiculi of the spinal cord. Myelin reduction was paralleled by axon reduction, suggesting that hypomyelination was a consequence of reduced axonal formation. A homozygous nonsense mutation in the thyroid peroxidase gene was identified in the affected puppies. The dam and a clinically normal litter mate were heterozygous for this mutation, confirming simple autosomal recessive inheritance of the disease trait. The same mutation, causing congenital hypothyroidism with a goiter was previously described in the Toy Fox Terrier breed. Given the ongoing practice of introducing the Toy Fox Terrier genetic background into some Rat Terrier breeding programs to obtain a smaller stature and the apparent relative incidence of the disorder in the 2 breeds, it is likely that this mutation crossed into the Rat Terrier breed from Toy Fox Terriers fairly recently.

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Combined cytosine arabinoside and prednisone therapy for meningoencephalitis of unknown aetiology in 10 dogs.

OBJECTIVES: The differential diagnosis for young to middle-aged dogs with progressive neurological signs, focal or multifocal computed tomography/magnetic resonance imaging lesions, mononuclear cerebrospinal fluid pleocytosis and negative infectious titres includes granulomatous meningoencephalomyelitis, breed-specific meningoencephalitis, infectious meningoencephalitis of unknown origin and central nervous system neoplasia. The terminology meningoencephalitis of unknown aetiology may be preferable for cases that lack histopathological diagnoses. The safety and efficacy of a combination of cytosine arabinoside and prednisone protocol is evaluated, in this study, for the treatment of meningoencephalitis of unknown aetiology in 10 dogs. METHODS: Cases were selected based on neuroanatomical localisation, negative regional infectious disease titres, cerebrospinal fluid pleocytosis and brain imaging. Clinical response was gauged through follow-up examinations, owner and referring veterinarian surveys and review of medical records. RESULTS: Partial or complete remission was achieved in all dogs; the median survival time for the 10 dogs was 531 days (range 46 to 1025 days), with five of the 10 dogs alive at the time of writing. CLINICAL SIGNIFICANCE: Prednisone/cytosine arabinoside is a safe empirical therapy for dogs with meningoencephalitis of unknown aetiology; this drug combination may prolong survival time.

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Evaluation of the thoraco-laryngeal reflex ('slap test') as an aid to the diagnosis of cervical spinal cord and brainstem disease in horses.

A study was conducted over a 12 month period to assess the specificity and sensitivity of the 'slap test', using endoscopic evaluation, in the detection of cervical spinal cord and caudal brainstem lesions in horses. Fifteen ataxic horses were subjected to the 'slap test' and subsequently examined post mortem. Twelve out of the 15 had histopathological lesions consistent with their clinical signs. Thirteen horses with no history of neurological dysfunction and no histopathological evidence of cervical spinal cord or brainstem disease were used as controls. The laryngeal adductory responses exhibited by all horses were filmed and later scored independently by 3 assessors. The proportion of animals diagnosed with cervical spinal cord and/or brainstem disease, defined by histopathological criteria, was found to be statistically similar to the proportion with abnormal 'slap test' responses, using the McNemar chi-Square test. Despite statistical significance between proportions, sensitivity of the 'slap test' was low, 50% for the left side on both days and 58% for the right side. Specificity was higher, 69% (Day 1) and 75% (Day 2) for the left side and 75% (Day 1) and 69% (Day 2) for the right side. In contrast to this, conventional neurological examination was found to be 100% sensitive and 81% specific in the detection of lesions of histopathological significance in the cervical spinal cord/caudal brainstem. Agreement between scores for the 'slap test' from the same assessor on different days was good, with values for kappa of 0.59 to 0.85. In contrast, agreement between assessors on the 'slap test' score was poor, with kappa 0.35.(ABSTRACT TRUNCATED AT 250 WORDS)

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Microgliomatosis in a Schnauzer dog.

Microgliomatosis was found in the central nervous system of a 7-year-old male Standard Schnauzer. History, neurologic examination, laboratory tests and electrodiagnostics could not localize the disease process in the central nervous system. The animal was not treated, continued to deteriorate, and was euthanatized approximately 8 weeks after clinical signs were first detected. Diagnosis was made upon histologic examination of the brain.

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Cuterebra encephalitis in a dog.

Encephalitis was diagnosed in a 3 1/2-month-old puppy, based on neurological signs, and cerebrospinal fluid examinations. Verminous encephalitis from a migrating Cuterebra sp. larva in the right cerebral hemisphere was confirmed at necropsy.

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MR imaging findings in a dog with intravascular lymphoma in the brain.

Intravascular lymphoma (malignant angioendotheliomatosis, angiotrophic lymphoma) is a rare neoplastic disorder in dogs. The literature contains few reports in dogs and a single report in a cat. Intravascular lymphoma is characterized by an intravascular proliferation of malignant lymphocytes. This unique angiocentric distribution of neoplastic cells leads to the characteristic clinicopathologic feature of thromboses and infarctions. In people, intravascular lymphoma has a predilection for vessels in the central nervous system (CNS) and skin. Typically, affected patients have episodic symptoms that coincide with the timing of infarctions. This report details the clinicopathologic description and magnetic resonance (MR) images of a dog with intravascular lymphoma that resulted in multiple CNS infarctions. Abnormalities identified with MR imaging consisted of multifocal hyperintensities observed in pre-contrast T1-weighted, T2-weighted, intermediate-weighted, and FLAIR pulse sequences. Lesions were most conspicuous on the FLAIR images. In addition, there was mild enhancement of the lesions seen in post-contrast T1 weighted images.

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