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Biomedical subjects

M Usui

Publications and source records attributed to M Usui.

At least 361 records · Page 20Linked to original sources
PubMed1977

Malignant granular cell tumor of the radial nerve: an autopsy observation with electron microscopic and tissue culture studies.

Malignant granular cell tumor closely associated with the radial nerve in the left upper arm, was found in a 34-year old man. The tumor increased rapidly in size, was locally invasive and showed recurrence and metastases to lymph nodes and the lungs. The tumor was composed solely of granular cells and its histological features were very similar to those of benign granular cell tumors. However, considerable variation of cellular size and shape, hyperchromatic plump nuclei, and some disordered cellular arrangement were thought to be significant indications of malignancy. Ultrastructural study of the tumor revealed many lysosome-like dense granules in the cytoplasm. The presence of a few axon-like cytoplasmic processes between granular cells and the intimate anatomical association of the tumor with the radial nerve seemed to support the concept of peripheral nerve origin of the malignant granular cell tumor.

Adult↗
PubMed1976

[Scanning electron microscopy study of experimental chorioretinitis in guinea pigs].

Retinal lesions are described with the scanning electron microscope in the uveo retinitis induced in guinea pigs by immunization with rod outer segments of bovine retina. The two surfaces in contact of the pigment epithelium and the photoreceptors are separated from each other and observed on flat preparations. On the epithelial side, the evolution of the degenerescence of epithelial cells is observed, from the early disappearance of villosities until the total destruction of the cells. Through lacks in the epithelial layer where the choroid appears, inflammatory cells migrate towards the retina. The impairement of the visual cells is characterized by progressive destruction of outer then inner segments, with preservation of the external limiting membrane. In some areas the degenerative process reaches the layer of visual cells nuclei. Macrophages, and local clusters of lymphocytes are seen in contact with the retinal surface.

Animals↗
PubMed1976

[Experimental autoimmune uveoretinitis. Ultrastructure of chorioretinal lesions induced in guinea pigs by immunization against the outer rods of the bovine retina].

The uveoretinitis induced in guinea pigs by one systemic injection of rod outer segments from bovine retina has the following ultrastructural features : 1 to 3 weeks after the injection, first early alterations of the visual cells and pigment epithelium, phagocytosis of fragmented outer segments by macrophages, development of an inflammatory infiltrate of the uvea with numerous plasma cells. During the second month, polymorphic inflammatory reaction in the choroid, destruction of photoreceptors in large areas with preservation of the external limiting membrane or involvement of the internal layers of the retina. During the next months, fibroblastic healing processes, but persistence of a diffuse inflammation, with sub-retinal lymphoid follicles and epithelioid cells. It appears likely that pigment epithelium and outer segments of the visual cells are targets for the initial immunological attack, where humoral antibodies seem to play a major role.

Animals↗