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Biomedical subjects

D Y Cho

Publications and source records attributed to D Y Cho.

68 records · Page 4Linked to original sources

Agenesis of corpus callosum in calves.

Agenesis of the corpus callosum is a rare brain defect in cattle, and was described in two calves. It was characterized by the total absence of the corpus callosum, septum pellucidum and hippocampal commissure. Fornices were present but separated. Both calves also had moderate internal hydrocephalus, micrencephaly and a CSF-filled cyst in the longitudinal fissure dorsal to the thalamus. Clinical signs were not specific. Etiology and pathogenesis are unknown. No evidence of inflammation or inheritance was found as cause of the defect.

Agenesis of Corpus Callosum↗

Experimental spongy degeneration in calves.

Experimental reproduction and ultrastructural findings of spongy degeneration of the central nervous system of hyperammonemic calves are described. Hyperammonemia was produced by intravenous infusion of ammonium acetate. Histologic findings were stereotyped in all calves and characterized by widespread vacuolation of white and grey matter of the brain spinal cord. Electron microscopy revealed widespread intramyelinic vacuoles, some expansion of extracellular spaces and swollen mitochondria. There were minimal changes in neurons, axons and glia, and little evidence of myelin breakdown. Hyperammonemia may be one of the pathogeneses involved in the CNS spongy degeneration in man and domestic animals effected with hepatocerebral diseases and some hereditary disorders.

Animals↗

Arnold-Chiari malformation and associated anomalies in calves.

The Arnold-Chiari malformation is described in 10 calves. Eight of them had internal hydrocephalus and/or spina bifida and two occurred as a single isolated defect without associated anomaly. Malformation of the base of the skull and large foramen magnum appeared to indicate that the abnormal embryonic development of the neural tissue and basal bone may contribute to the development of the Arnold-Chiari malformation in cattle.

Animals↗

Syringomyelia in a thoroughbred foal.

The report describes a case of myelodysplasia involing spinal cord segments C7 to T8 of a 5 month old part-Thoroughbred foal. There was a single extensive syringomyelic and hydromyelic cavity which extended from the seventh cervical segment (C7), to the seventh thoracic segment (T7), abnormal size and shape of central canal, and disorderly differentiation of the grey and white matter. The cause of the defect is unknown.

Animals↗

Hypervitaminosis A in the dog.

Toxic effects of excessive vitamin A and of excessive vitamin ADE were studied in 9 mixed Labrador Retriever pups. Clinical signs were loss of body weight, dullness, emaciation, roughened coat, evident pain in limb joints, and retarded growth. Radiologic changes were decreases in overall length and thickness of long bones, development of osteophytes, periosteal reaction, and premature closure of epiphyses. Pathologic changes were degenerative epiphyseal plate, hemorrhage and exostotic proliferation of periosteum, fatty liver, and microcalculi in kidney. Toxic effects of excessive vitamin A did not appear to be so great when it was administered as vitamin ADE.

Animals↗

Familial cerebellar ataxia with hydrocephalus in bull mastiffs.

Familial cerebellar ataxia with concurrent hydrocephalus has previously been described in a family of bull mastiff pups, and recently has been identified in a litter from Louisiana. The 4 affected pups had ataxia, hypermetria, conscious proprioceptive deficits, behavioral abnormalities, and a visual deficit. In magnetic resonance imaging of the brain of two of the pups, there were symmetric hydrocephalus and two focal areas of increased signal intensity within the central nuclei of the cerebellum. Histopathologically there was vacuolization and mild astrogliosis within the deep cerebellar nuclei (dentate, interpositus, fastigial), caudal colliculi, and lateral vestibular nuclei. Although the postmortem results were not exactly the same as in the previously published report, the clinical features and histopathologic findings strongly support the diagnosis. This disorder is most likely inherited in an autosomal recessive manner.

Animals↗

Eastern equine encephalitis in a flock of emus (Dromaius novaehollandiae).

Eastern equine encephalitis (EEE) was diagnosed in a flock of emus in southeastern Louisiana. The outbreak involved juvenile and adult breeders ranging in age from 20 to 36 months, with an attack rate of 76% and a case fatality rate of 87%. The diagnosis was confirmed by isolation and characterization of the viral agent, and by detection of EEE antibody in two recovered emus. High mortality was preceded by marked depression, hemorrhagic diarrhea, and emesis of blood-stained ingesta. On postmortem examination, hemorrhagic enteritis and multiple petechia of viscera were observed. Microscopic changes included severe necrosis of hepatocytes, intestinal mucosa, and necrotizing vasculitis of the spleen and lamina propria of the intestine. No nervous system lesions were observed. This outbreak occurred concurrently with EEE in horses and was attributed to unseasonably heavy rainfall with an abundance of arthropod vectors and proximity to free-living reservoir host species.

Animals↗

Thiopurine S-methyltransferase polymorphisms and the relationship between the mutant alleles and the adverse effects in systemic lupus erythematosus patients taking azathioprine.

OBJECTIVE: The present study sought to elucidate the genetic basis of thiopurine methyltransferase (TPMT) polymorphism and subsequently to investigate the relationship between mutant TPMT and an adverse response observed in Korean patients with systemic lupus erythematosus (SLE) taking azathioprine (AZA). METHODS: The TPMT genotype of 342 patients with SLE was determined by MALDI-TOF mass spectrometry and correlated with the effects of clinical exposure to AZA. RESULTS: TPMT polymorphism was detected in 17 of the 342 study subjects (5.0%), 12 heterozygous for the TPMT*3C allele and 5 heterozygous for the TPMT*6 allele. Numerous patients taking AZA demonstrated adverse drug responses. Severe nausea occurred in 4 patients with the TPMT*3C allele, while 1 patient with the TPMT*6 allele suffered severe bone marrow toxicity. Leucopenia (n = 17), nausea (n = 4), and abnormal liver function (n = 1) were suspected in 23 of the 94 lupus patients taking AZA. AZA was relatively well tolerated by the remainder of the patients. The heterozygous genotype for the TPMT*3C and *6 alleles was frequently detected in Korean SLE patients. CONCLUSION: Contrary to previous hypotheses, this study identified no statistical correlation between TPMT genotype and AZA toxicity. We thus conclude that TMPT genotyping cannot replace regular blood monitoring in SLE patients receiving AZA treatment.

Adolescent↗

Chlamydiosis in commercial rheas (Rhea americana).

Mild to marked splenomegaly was observed in three of four rheas that died acutely in three unrelated commercial ratite facilities in Southeastern Louisiana. Mortalities occurred within a 5-week period in birds ranging from 2 months to 3 years of age. Multifocal hepatic and splenic necrosis with mononuclear cell infiltrates, typical of chlamydiosis in other avian species, was present on histopathologic sections. The diagnoses were confirmed by demonstration of inclusion bodies in splenic impression smears and fluorescent-antibody testing performed on Vero cell cultures.

Animal Husbandry↗