Biomedical subjects

Yu Yamamoto

Publications and source records attributed to Yu Yamamoto.

7 recordsLinked to original sources

PubMed2006

Spectral restoration and energy resolution improvement of electron energy-loss spectra by Pixon reconstruction: II. Application to practical ELNES analysis of low SNR.

We applied Pixon deconvolution as introduced in Part I to several practical, examples of low signal-to-noise ratio (SNR), electron energy-loss spectra with a goal toward restoring their fine spectral features and/or improving the energy resolution. We demonstrate that by directly fitting the two-dimensional spectral data recorded on the CCD; the method enables us to reveal fine spectral structures. Consequently, Pixon reconstruction extends the ability to probe electronic states in very spatially localized areas, a capability currently unique to our method.

Algorithms↗

PubMed2006

Site-specific electronic structure analysis by channeling EELS and first-principles calculations.

Site-specific electronic structures were investigated by electron energy loss spectroscopy (EELS) under electron channeling conditions. The Al-K and Mn-L(2,3) electron energy loss near-edge structure (ELNES) of, respectively, NiAl2O4 and Mn3O4 were measured. Deconvolution of the raw spectra with the instrumental resolution function restored the blunt and hidden fine features, which allowed us to interpret the experimental spectral features by comparing with theoretical spectra obtained by first-principles calculations. The present method successfully revealed the electronic structures specific to the differently coordinated cationic sites.

Journal Article↗

PubMed2006

Nephroblastoma with transcoelomic metastasis in a Japanese black bull.

This paper describes a nephroblastoma with transcoelomic metastasis in a three-year-old Japanese black bull. At necropsy, a huge, oval neoplastic mass containing the residual right kidney was found. Moreover, severe transcoelomic metastasis occurred throughout the abdominal and thoracic cavities. Histologically, the mass was mainly composed of sheets, nests, islands and cords of polygonal blastemal cells with trabeculae of fibrous stroma. In some areas, epithelial elements composed of tubules and winding duct-like structures were also observed. Glomeruloid structures were scattered in these epithelial elements. Metastatic nodules were composed of blastemal and stromal elements, which were similar to those in the mass.

Abdominal Neoplasms↗

PubMed2006

Pathology of cutaneous fowlpox with amyloidosis in layer hens inoculated with fowlpox vaccine.

Cutaneous fowlpox occurring in vaccinated layer hens was investigated pathologically and microbiologically. Anorexia, decrease of egg production, increased mortality, yellow scabs on faces, and alopecia of feathered skins with yellow scabs were observed in affected hens. Histologically, proliferative and necrotic dermatitis with eosinophilic ring-shaped cytoplasmic inclusions (Bollinger bodies) and clumps of gram-positive cocci (Staphylococcus hyicus) were noted in the affected birds. Fowlpox lesions were primarily observed in the feathered skins. Proliferation of feather follicle epidermal cells, with cytoplasmic inclusions and degeneration of the feather, and bacterial clumps in the feather follicles were noted in the affected skins. Ultrastructurally, characteristic fowlpox viral particles were observed in the cytoplasmic inclusions of hyperplastic epidermal cells. Amyloid deposition was observed in the Disse space of the liver, splenic sinus, and lamina propria of the bronchiolar, bronchial, and tracheal areas. Amyloidosis could be one factor inducing the fowlpox infection in vaccinated chickens.

Amyloidosis↗

PubMed2006

Encephalomalacia with Enterococcus durans infection in the brain stem and cerebral hemisphere in chicks in Japan.

Fourteen chicks, 7-12 days old, that died or had neurological signs (depression, paralysis, torticollis, incoordination, and rolling) were investigated pathologically and microbiologically. Variably sized foci of malacia were present within the parenchyma of the brain stem (cerebral peduncle, optic lobe, and medulla oblongata) and the cerebral hemisphere. Capillary thrombosis with congestion and hemorrhage was frequently observed within the malacia lesions. Gram-positive cocci were recognized in the blood capillary of malacia lesions. Bacteriologically, Enterococcus durans was isolated from the brain, liver, kidney, lung, and spleen. Detection of gram-positive cocci within the blood vessels in the malacia lesions observed in these cases may more strongly suggest the pathogenic role of E. durans on the malacia lesions in the brain stem and cerebral hemisphere.

Animals↗

PubMed2005

Therapeutic effect of modified oligopeptides from the beetle Allomyrina dichotoma on methicillin-resistant Staphylococcus aureus (MRSA) infection in mice.

Anti-bacterial activity of two synthesized oligopeptides, RLYLRIGRR-NH2 (peptide A) and RLRLRIGRR-NH2 (peptide B), both which based on a putative active site of defensin, an anti-bacterial peptide from the beetle Allomyrina dichotoma, was examined by macroscopic and histopathologic assessment during the course of infection in mice inoculated with methicillin-resistant Staphylococcus aureus (MRSA) in vivo. Both peptides A and B decreased the mortality of mice inoculated with MRSA. Peptides A and B decreased the macroscopical and histopathological lesions by MRSA infection in mice even seven days after the challenge. The anti-bacterial activity of peptides A and B has a therapeutic effect on MRSA infection in mice even seven days after being challenged.

Animals↗

PubMed2005

Epidemiology, pathology, and immunohistochemistry of layer hens naturally affected with H5N1 highly pathogenic avian influenza in Japan.

Epidemiology, pathology, and immunohistochemistry were investigated in layer hens affected with H5N1 highly pathogenic avian influenza, which occurred for the first time in 79 years in Japan. The farm, which had a total of 34,640 chickens, experienced up to 43.3% mortality before the chickens were depopulated. Clinically, the affected chickens exhibited mortality without apparent clinical signs. Histologically, hepatocytic necrosis; necrosis of ellipsoids and follicles with fibrin in the spleen; necrosis with glial nodules in the brain stem, cerebrum, and cerebellum; necrosis of acinar cells in the pancreas; and necrosis of lymphoid tissues in intestinal lamina propria were seen. Occasionally, mild bronchiolitis, degeneration of smooth muscle fibers in the cecum, and mild tubulonephrosis were noted. Immunohistochemically, influenza virus antigens were detected often in the liver and spleen, heart, intestine, gizzard, proventriculus, and oviduct. In addition, antigens were seen also in the brain, kidney, pancreas, and ovary, but seldom in the lung and trachea. Virus antigen was mainly detected in the capillary endothelium and parenchymal cells. This suggests that virus excretion from the respiratory tract was not as prevalent as that from the digestive tract in the present cases.

Animals↗