Krabbe's disease in two West Highland White terriers.

Two 3-month-old male West Highland White terriers were referred for progressive neurological disease. Histological examination of the central nervous system of the animals euthanized at the owner' request, revealed diffuse, bilateral and symmetrical white matter lesion consisting of varying degrees of demyelination and axonal degeneration. Accumulation of round to ovoid large mononuclear cells was especially observed along the blood vessels in the white matter. These cells were characterized by central or eccentric nuclei and highly eosinophilic, granular and PAS-positive cytoplasm. Stored material was stained with toluidine blue both at pH 4 and pH 11 and exhibited a strong PAC and no PALK activities. Staining for lectins revealed a positivity using Ricinus communis agglutinin-I, Ricinus communis agglutin-II, Triticum vulgaris and Concavalin A. Histochemical evaluation of intracellular material was performed on the kidney and on the liver, too. Ultrastructural investigations allowed to observe the cytoplasmic contents of globoid cells that is an admixture of degraded myelin membranes and different kinds of tubular aggregates. To verify if the two dogs bore the mutation at position 473, a method involving PCR amplification of genomic DNA followed by restriction-digestion was used. The diagnosis of Krabbe's disease was performed based on the clinical evaluation, morphological, histochemical and ultrastructural features.

Histological and immunohistochemical study of a neuroblastoma in a dog.

A 13-year-old, male German Shepherd dog was euthanasized for a frontal temporal mass revealed by the MRI. The histological examination showed a proliferation composed of small round undifferentiated cells arranged in sheets or nests and sometimes in pseudorosettes interrupted by hypocellular zones of fibrovascular stroma. Immunohistochemical studies revealed the expression of neuroblastic epitopes. The presented neoplasm has many histological and immunohistochemical features in common with the group of olfactory neuroblastomas reported in man, so it could be classified as primitive neuroectodermal tumor with neuronal differentiation.

Necrotizing encephalitis in a Yorkshire Terrier: clinical, imaging, and pathologic findings.

A 5-year-old, male Yorkshire Terrier had chronic and progressive neurologic signs compatible with lesions in the right brain stem and right forebrain. In magnetic resonance images of the brain there were multifocal lesions at different stages of evolution, consistent with an inflammatory disease. The lesions were located in the white matter of the cerebrum, in the diencephalon and mesencephalon. These lesions were hypointense in T1-weighted images and hyperintense in T2-weighted images with no mass effect and minimal enhancement with gadolinium. Necrotizing encephalitis was confirmed post mortem.

Beta-galactosidase deficiency in a Korat cat: a new form of feline GM1-gangliosidosis.

A 7-month-old Korat cat was referred for a slowly progressive neurological disease. Circulating monocytes and lymphocytes showed the presence of single or multiple empty vacuoles and blood leukocytes enzyme assay revealed a very low beta-galactosidase activity level (4.7 nmol/mg per h) as compared to unaffected parents and relatives. Histologically, the cat, euthanized at the owner request at 21 months of age, presented diffuse vacuolization and enlargement of neurons throughout the brain, spinal cord and peripheral ganglia, severe cerebellar neuronal cell loss, and moderate astrocytosis. Stored material was stained with periodic acid-Schiff on frozen sections and with the lectins Ricinus conmmunis agglutinin-I, concanavalin A and wheat germ agglutinin on paraffin-embedded sections. Ultrastructurally, neuronal vacuoles were filled with concentrically whorled lamellae and small membrane-bound vesicles. In the affected cat, beta-galactosidase activity was markedly reduced in brain (18.9%) and liver (33.25%), while total beta-hexosaminidase activity showed a remarkable increase. Quantitation of total gangliosides revealed a 3-fold increase in brain and 1.7-fold in liver of affected cat. High-performance thin layer chromatography (HPTLC) detected a striking increase of GM1-ganglioside. On densitometric analysis of HPTLC bands, the absorption of GM1-ganglioside band was 98.52% of all stained bands (GD1a, GD1b, GT1b). Based on clinical onset, morphological and histochemical features, and biochemical findings, the Korat cat GM1-gangliosidosis is comparable with the human type II (juvenile) form. However, clinical progression, survival time and level of beta-galactosidase deficiency do not completely fit with those of human type II GM1-gangliosidosis. The disease in the Korat cat is also different from other reported forms of feline GM1-gangliosidosis.

Cytological, immunocytochemical and biochemical cerebrospinal fluid investigations in selected central nervous system disorders of dogs.

Cerebrospinal fluid (CSF) obtained from 20 clinically healthy dogs and from 15 dogs affected by neurological disorders were examined for total and differential cell counts, immunocytochemistry for canine distemper virus antigen, total protein concentration and electrophoretic separation, and glucose and enzyme determination. Dogs affected by canine distemper showed an increase in macrophages, presence of specific inclusion bodies, and an increase in total protein concentration and gamma-globulin fraction. In bacterial meningoencephalomyelitis pleocytosis, increase of total proteins with special regard to high molecular weight proteins, elevated levels of lactate dehydrogenase (LDH), alterations of LDH isoenzyme profile, and decrease in glucose levels were detected; inflammatory disorders were more often characterized by an increase in LDH level, while in non-inflammatory disorders (hydrocephalus and spinal cord neoplasia) no variation in LDH levels was detected. Analysis of CSF in dogs appears relatively easy to perform and may help in establishing the condition of the blood-brain barrier as well as in the diagnosis of neurological disorders.