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Biomedical subjects

Y Nagato

Publications and source records attributed to Y Nagato.

48 records · Page 3Linked to original sources
PubMed1983

Observation on backscattered electron image (BEI) of a scanning electron microscope (SEM) in semi-thin sections prepared for light microscopy.

In order to examine semi-thin section for light microscopy with the backscattered electron mode (BE mode), identical sites in tissue sections were comparatively observed with both light microscopy and BE mode. Tissue blocks (ca. 3 X 3 X 1 mm) were fixed in glutaraldehyde or combined formaldehyde-glutaraldehyde solution. After dehydration in alcohol, they were embedded in Kushida's GMA-Quetol 523. 1.0 micron sections on glass slides coated with indium oxide were stained with hematoxylin-eosin or toluidine blue or by the Giemsa method, and then treated with osmium tetroxide vapor or aqueous KMnO4 solution or uranyl acetate-lead citrate solution. The identical places of such sections could be examined with the accelerating potential of 6 kV and the probe current of 8 X 10(-10) A using a JSM-35C SEM with BEIS BE detector. Photographs were taken with the 2500-line resolution cathode ray tube and the time of exposure was 100 sec. The sections were placed at a distance of 5mm from the BE detector. BE images from osmium tetroxide vapor staining showed a distinctly improved contrast especially when the sections were previously stained with hematoxylin and eosin. The cellular structure was clearly demonstrated under the electron microscope in the BE mode. Identical sites in tissue samples could be compared exactly with both light and electron micrographs.

Animals↗
PubMed1982

Light and electron microscopic observations of glycogen in semi-thin sections employing GMA, Quetol 523 and methylmethacrylate.

The use of improved GMA-Quetol 523 or GMA-Quetol 523 methyl methacrylate (MMA) mixture as an infiltration medium for the histochemical demonstration of glycogen has been devised to facilitate embedding, sectioning and staining. An improved method of infiltration uses such mixtures with a double weight of QCU-1 as a catalyst. Since the double weight of catalyst prevents interference by bleeding of picric acid from tissue blocks into the resin mixtures, improved mixtures penetrate readily and completely into the tissue fixed in picric acid-formaldehyde-glutaraldehyde solution (PAFG). PAFG solution has been found suitable for the histochemical fixation of glycogen in semithin sections. In hepatocytes specific reaction products appeared a deep reddish-purple after periodic oxidation and Schiff's reaction (PAS reaction), which was lost in previous digestion by means of salivary deastase. Glycogen can be identified as a PAS positive area in semi-thin sections 0.2-0.3 micrometers thick under the light microscope. Identical reactions sites of such sections show a high contrast in electron microscopy without any staining by either heavy metals or osmium tetraoxide vapor. It was therefore demonstrated that total glycogen produced after PAS reaction was revealed distinctly with deep contrast precipitates. This method provides significant morphological data for the histochemical localization of glycogen.

Acrylates↗
PubMedDate not supplied

Interstitial tumour cell invasion in small hepatocellular carcinoma. Evaluation in microscopic and low magnification views.

In order to study the process of hepatocellular carcinoma (HCC) development, and to search for a clue to histologic diagnosis of well-differentiated HCC (wd-HCC), interstitial invasion in small HCC was evaluated. The study material consisted of 35 cases of HCC that were smaller than 3 cm that comprised 17 cases of wd-HCC, 18 cases of moderately or poorly differentiated classical HCC (cl-HCC), and 20 cases of large regenerative nodules (LRN). Interstitial invasion was microscopically classified into three patterns: (i) crossing type, in which HCC was invading across fibrous septa of tumour nodules; (ii) longitudinal type, in which tumour cells were growing longitudinally within fibrous septa; and (iii) irregular type, in which the portal area was irregularly invaded by HCC. The crossing type was found in two cases (12%) of wd-HCC and 10 cases (56%) of cl-HCC while the longitudinal type was observed in 16 cases (94%) of wd-HCC and eight cases (44%) of cl-HCC. The irregular type was frequently seen in wd-HCC (15 cases, 88%), and cl-HCC (12 cases, 67%). No interstitial invasion was observed in LRN. Interstitial invasion could be recognized even in the low magnification view of histological specimens, with a detection rate of 59% (10 cases) in wd-HCC and 72% (13 cases) in cl-HCC. These results suggest that evaluation of interstitial invasion is useful in diagnosing wd-HCC independent of cellular atypia. In addition, such invasive growth is revealed to play an important role in destroying original hepatic architecture during its developmental process from the early to advanced stages.

Carcinoma, Hepatocellular↗