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Biomedical subjects

E Okada

Publications and source records attributed to E Okada.

122 records · Page 7Linked to original sources
PubMed1976

Dysmyelination in the sciatic nerves of dystrophic mice.

Ultrastructural alterations were observed in the sciatic nerve of dystrophic mice. Myelin sheaths were abnormal in shape, abruptly ceased beyond a node of Ranvier, leaving the axon naked. These changes were seen in both afferent and efferent nerve fibres. Apparent embryonal Schwann cells and Schwann cells which were associated with increased lysosomes in the cytoplasm were observed in the proximal portion. There is a relative decrease in Schwann cells in the cross-section of the radicular parts, and a relative increase in the distal parts. The mean number of neurotubules per unit area was smaller while the mean number of the neurofilaments was larger in U-axons, in the dystrophic mice than in the controls. In M-fibres, neurotubules and neurofilaments showed no significant difference between systrophic and control mice.

Animals↗
PubMed1975

Abnormalities of the sciatic nerves of dystrophic mice, with reference to nerve counts and mean area of axons.

Ultrastructural changes of the sciatic nerves of c58bl/6j-dydy mice were examined. Nerve counts were calculated and the area of axons was measured in these nerve tissue. Many large bundles of unmyelinated nerves were observed at the proximal portion of the sciatic nerve without cytoplasm or basement membrane of the Schwann cell. These bundles were composed of axons of various sizes and shapes, including some vary large axons. The large unmyelinated axons decreased in number and size as nerves descended to the distal portion. The myelinated nerves showed irregular shapes. Some myelinated nerves were enveloped in very thin myelin sheaths for the mouse age. The destructed myelin was often observed from the radix to the distal portion of sciatic nerves. They lost their myelin sheaths at the Ranvier node, and descended for long distances with naked axons. The neighboring myelin segments of naken axons showed unusually bizarre shapes. They seemed to be the abnormal development of the demyelinated axons. Such findings were very similar to those of the embryonal developing peripheral nerves. It was concluded that the muscular dystrophy of the C57BL/6J-dydy mice might be related to dysmyelination and to the decrease in the number of myelinated nerves.

Animals↗
PubMedDate not supplied

Asbestos fiber analysis in seven asbestosis cases.

Asbestos bodies and fibers deposited in the lungs of seven asbestosis cases were counted after tissue digestion. The types and sizes of 100 asbestos fibers for each case were also analyzed. Asbestos bodies were counted with an optical microscope at 100x magnification, and asbestos fibers were counted with a transmission electron microscope (TEM) at 2000x magnification. Most asbestos fibers detected with TEM were longer than 3 microns (92.5%) and thicker than 0.1 microns (92.3%). Short fibers less than 2 microns--both chrysotile and amphiboles, as well as long, thin fibers less than 0.06 microns--would be missed at 2000x (TEM). An average of 1.37 (0.081-5.5) x 10(6) asbestos bodies and 164.8 (0.55-610) x 10(6) asbestos fibers per 5 g wet (0.88 g dry) lung tissue were found, and these values are higher than what was reported in mesothelioma cases without asbestosis that were reported previously. More than 13 (average = 266.2) asbestos bodies were found in a 4-micron-thick tissue section (average area = 3.24 cm2). One asbestos body in a section equaled approximately 5,000 per 5 g wet lung tissue. The intensity of fibrosis was minimal in one case, mild in four, moderate and severe in one each, and the intensity was correlated with the number of asbestos bodies and fibers. The fibrosis in the severe case may have been intensified by repeated infection. Crocidolite fibers were found most frequently (84.7%), were thin, and had a high aspect ratio by our counting rules. Crocidolite with a high aspect ratio may be most fibrogenic in the lung.

Adult↗