Biomedical subjects

Y Ohwada

Publications and source records attributed to Y Ohwada.

10 recordsLinked to original sources

PubMed2000

Method to determine temperature distribution and intrinsic emissivity of a cavity

A method is presented to determine simultaneously the temperature distribution and the intrinsic emissivities of a cavity surface when radiance distributions along the cavity wall for two wavelengths are given. The intrinsic emissivity and reflection characteristics are assumed not to depend on position on the cavity wall. The intrinsic emissivity and reflection characteristics giving the smallest difference between calculated temperature distributions for the two wavelengths are found. The values found and thus the temperature distributions are verified to be close to the true ones. The method is examined on a cylindrocone by a simulation and applied to radiance temperature distributions measured on a commercially available double cone.

Journal Article↗

PubMed1999

GM2 gangliosidosis AB variant: clinical and biochemical studies of a Japanese patient.

OBJECTIVE: To determine the clinical features and biochemical basis of the first Japanese patient with the GM2 gangliosidosis AB variant. METHODS: The clinical manifestations and laboratory findings in the patient were investigated. Cultured fibroblasts from the patient were analyzed by means of immunofluorescence staining with an anti-GM2 ganglioside monoclonal antibody and thin-layer chromatography and immunostaining. GM1 ganglioside catabolism in cultured cells was analyzed by pulse labeling, and the amount of GM2 activator in cells was determined by Western blot analysis. Gene analysis was performed according to standard protocols. RESULTS: The patient showed progressive neurologic manifestations of quite early onset. Muscular weakness and hypotonia became evident by 1 month of age, and the patient then developed a startle reaction, severe psychomotor retardation, and myoclonic seizures. Immunocytochemical analysis clearly revealed the accumulation of GM2 ganglioside in cultured fibroblasts from the patient, and thin-layer chromatography confirmed it. Western blot and metabolic studies showed a complete deficiency of GM2 activator. Gene analysis did not reveal any mutations in the protein coding region of the GM2 activator gene. CONCLUSION: The clinical features and biochemical basis of this Japanese patient with GM2 gangliosidosis AB variant were determined. Immunocytochemical analysis using cultured fibroblasts as samples is available for the diagnosis of this disease.

Anticonvulsants↗

PubMed1994

Neuromyelitis optica.

An 11-year-old girl developed sudden visual loss in her left eye, preceding subacute myelitis by 9 months. Multifocal lesions in the central nervous system were demonstrated by magnetic resonance imaging. Although unilateral blindness is unusual, the clinical findings predominantly involving the optic nerve and spinal cord were consistent with the diagnosis of neuromyelitis optica (NMO). This case provides additional evidence to support the view that NMO is a variant of multiple sclerosis.

Blindness↗

PubMed1993

Ultrastructural localization of DNA in leukemic cells using osmium ammine B.

In order to determine whether there were any differences in distribution of nuclear DNA between acute lymphocytic leukemia (ALL) and acute myelogenous leukemia (AML), the localization of DNA in blasts from the bone marrow or buffy coat of 30 patients with ALL and 30 patients with AML was examined ultrastructurally by staining with osmium ammine B. By the ultrastructural cytochemistry, DNA in ALL cells was clumped in the nuclei, while in AML cells, it was dispersed. DNA had accumulated around the nucleoli of some blasts, and flecks of DNA were observed in nucleoli of a majority of blasts. The perinucleolar and intranucleolar DNA distribution could be classified into four types. The types with abundant perinucleolar DNA were frequently observed in ALL blasts, while the majority of AML blasts showed scant perinucleolar DNA. The types with intranucleolar flecks of DNA were more prominent in leukemic cells than in normal immature leukocytes. In conclusion, the pattern of distribution of DNA in the nuclei of leukemic cells differs between ALL and AML.

Adolescent↗

PubMed1993

Ultrastructural investigation of DNA in megakaryoblastic leukemia by using osmium-ammine-B: comparison with several types of leukemia.

Using DNA staining with highly stable osmium-ammine-B, the blasts of AMKL were observed under an electron microscope, in comparison with AML, ALL, CML-MK crisis and TMD. The DNA within the nucleus of the megakaryoblasts was observed as a high electron-density substance and tended to be uniformly dispersed within the nucleus. DNA, associated with nucleoli, could be roughly divided in four types based on the presence or absence of peri-nucleolar clumps and intra-nucleolar clumps. In cases of AMKL, we often observed a type that did not have peri-nucleolar DNA clumps but did have DNA flecks within the nucleoli. By analytical evaluation there were no differences among cells from several subtypes of megakaryocytic leukemia, such as AMKL in children with Down's syndrome, AMKL in children without Down's syndrome, AMKL in adults, and CML-MK crisis. The DNA distribution of TMD blasts, which were self-limited and not malignant, resembled that of AMKL blasts.

Adolescent↗

PubMed1976