It is generally accepted that nerve fiber conduction velocity is directly proportional to the fiber diameter under the condition, based on a supposition, that the transverse area of axons is normally maintained constant. Using an ideal preparation method for the purpose of axonal discrimination, we examined 43 human spinal cords after making transverse sections at the cervical, thoracic, lumbar and sacral levels and found a tapering of the axons in the lateral pyramidal tract, as the cross-sectional area of the pyramidal axons showed a definite decrease from the cervical to the sacral levels. Our results contradict the supposition that the transverse area of axons is normally maintained constant, which has for a long time been believed to be true without any evidence for it.

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Using an ideal tissue preparation method, we found a definite correlation between various human neuronal somata from the view point of accurate morphometry and functional evaluations. We believe this study may be of value, or even indispensable in the correct understanding of neurological symptomatology and phenomenology.

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We observed the three-dimensional structures of the external surface and connective tissue cores (CTCs), after exfoliation of the epithelium of the lingual papillae (filiform, fungiform and foliate papillae) of the Japanese badgers (Meles meles anakuma) using scanning electron microscopy and conventional light microscopy. Macroscopically, the tongue was elongated anterior-posteriorly and the apex rounded. Numerous filiform papillae and fungiform papillae were distributed all over the tongue except at the root. Seven vallate papillae were observed that had circumferential furrows and were arranged in V-shape. Numerous taste buds were observable in the furrows. Instead of foliate papillae, a lateral organ lacking taste buds was present on the lateral edge of the posterior tongue. Behind the vallate papillae, dome-like lingual tonsils that had globular tonsils were densely distributed in U-shaped arrangement. Rather long conical papillae were distributed around the vallate papillae. At the posterior end of the root of the tongue, lingual papillae were very much attenuated and only fold-like structure was seen. CTCs of filiform papillae had a main rod-like slender core and ovally arranged short accessory cores distributed around the main core. CTCs of fungiform papillae exhibited a columnar like appearance. The lingual papillae of Japanese badger’s tongue fundamentally had morphological similarity with carnivore species, included the Pinnipedia.

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The aim of the study was to analyze morphological changes of the epithelial surface and underlying connective tissue cores (CTCs) of the lingual mucosa in the rat using a DMBA induced pre-cancerous experimental model. Lightmicroscopically, initially DMBA treated sections exhibited infiltration of chronic inflammatory cells. At 16 weeks, aldehyde-fuchsin (AF) positive elastic fibers decreased and were scanty in the juxtaepithelium. On the other hand, rather densely packed thick bundles of AF positive fibers were observable in the deep layers of lamina propria. Carcinomas were not found at any stage, however, epithelial dysplasia was observed at 24 weeks post-treatment with DMBA. Scanning electron microscopy revealed an irregular arrangement of filiform papillae 4-12 weeks following DMBA stimulation. Patchy degenerated areas were observed especially at 16-24 weeks post-treatment and filiform papillae were totally attenuated on the central part of the degenerated areas. After removal of the epithelium, attenuated CTCs were observed from 4-8 weeks. Morphology of CTCs seemed to be gradually remodeled and severely altered in the later stage. The CTCs were however attenuated and exhibited a patchy distribution. The animal experimental model in this study revealed degenerative morphological changes of CTCs of the lingual papillae in the precancerous stage induced by DMBA.

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We performed a morphological study in type 2 diabetes mellitus (DM) model rats by focusing on the connective tissue papillae (CTPe) and capillary loops (CLs) of filiform papillae in the lingual dorsum in the type 2 DM model rats (GK rats). The normal group comprised nine 8-week-old male Wistar rats. The DM group comprised nine 8-week-old male GK rats. Image analysis of light microscopic specimens in CTPe was performed (height and cross-sectional area). Image analysis of scanning electron microscopic specimens (acrylic plastic injection method) in CLs was performed (number, thickness, height, interval between the tops of the two CLs, and crossing ratio between ascending and descending crura (CRC)). We compared these values between both groups (Student’s t test). The former analysis revealed that the height and cross-sectional area of CTPe were smaller in the DM group than in the normal group. The latter analysis revealed that the thickness, height, and CRC of the CLs were smaller in the DM group than in the normal group. However, no significant differences were detected in the number and interval of CLs between both groups. Therefore, we concluded that DM caused regressive change in CTPe and CLs.

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We histochemically investigated the radioprotection of organelle in acinus on the submandibular gland using amifostine. Mice were divided into those without amifostine administration or irradiation (group A), with amifostine administration and without irradiation (group B), without amifostine and with 5 Gy of irradiation (group C), and with amifostine and 5 Gy of irradiation (group D). In groups B and D were given 100 mg/kg of amifostine at 30 minutes prior to irradiation to the area equivalent to the submandibular gland. HE staining revealed that group D showed atrophy of the acinar cells, though the change was milder than that seen in group C. In AZAN-Mallory staining, fibrogenesis were found more often in group C as compared to the other groups. In Light Microscopic Autoradiography findings, the ratio of reduced silver particles in the acinar cells was lower in group C than in the other groups at 30 minutes after RI administration. Microstructure findings showed the findings were very similar to those of group A. In Electron microscopic Autoradiography, the ratio among the secretory granules was lower in group C at 120 minutes after RI administration. Our results indicate that amifostine can alleviate xerostomia caused by late effect from radiation.

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