Kenichi Takaya

Elastic fibers associated with collagenous fibrils surrounded by reticular cells in lymph nodes of the rat as revealed by electron microscopy after orcein staining

SummaryElectron microscopy of the rat lymph node disclosed reticular cells in close association with bundles of collagenous fibrils 30–45 nm in diameter, and electron lucent “amorphous” substances surrounded by microfibrils 11 nm in diameter, with junctional complexes. The amorphous substances, distinctly revealed by orcein staining, and the microfibrils showed morphological characteristics of elastic fibers. Since elastase digestion of 2% glutaraldehyde fixed specimens induced the selective disappearance of the orcein-stainable substances, it was concluded that they are elastin. Elastin often had a close contact with the plasma membrane of reticular cells. It is suggested that reticular cells synthesize elastic fibers.

Light- and electron-microscopic study of the endolymphatic sac of the tree frog, Hyla arborea japonica.

SummaryThe endolymphatic sac of the tree frog and its crystals were observed by light- and electron microscopy. Scanning electron microscopy revealed that the crystals have a faceted body and two pointed ends. Light- and transmission electron microscopy revealed that the endolymphatic sac is composed of many small chambers. In their lumina, numerous “ghosts” of crystals that resulted from decalcification were observed. The ghosts were demarcated by a linear dense material or embedded in a flocculent substance. The epithelium of the endolymphatic sac is simple squamous or cuboidal and peculiar cytoplasmic granules are found in most cells. The granules are surrounded by a limiting membrane and have varying electron density. Some granules contain a core and/or tubular structures. Vacuoles containing large ghosts are also found in the epithelial cells. These ghosts were quite similar to those in the lumen and sometimes coexist with cell debris. The fine structure of the endolymphatic sac and its crystals is discussed.

The fine structure of atypical ciliated cells in the human gastric epithelium

SummaryGastric mucosa obtained from the body and pyloric portions of the human stomach were observed by light and transmission electron microscopy. Ciliated cells were found in two of 18 subjects examined, one patient with gastric ulcer and the other one with gastric adenocarcinoma. The ciliated cells were found in epithelia at sites away from the main lesions. The tissues containing ciliated cells showed intestinal metaplasia combined with mild chronic gastritis in both cases. The epithelial layer facing the gastric lumen was composed of columnar cells with numerous uniform microvilli and goblet cells. This epithelium extended to the superficial parts of the tubules surrounded by the lamina propria. The deeper portions of the tubules were composed of mucous secretory, endocrine, and rarely ciliated cells. These ciliated cells were provided with numerous cilia the numbers of which varied considerably from cell to cell. This was in contrast to the primary cilium which is usually single. The central part of the apical cell membrane was sometimes concave in the area from where cilia tended to arise. It was also observed that numerous basal bodies as well as mucus-like granules were contained in the same cell. The axonemal pattern was different from that of ordinary cilia and showed 9 + 0 and 8 + 1 patterns. In longitudinal sections it was found that one peripheral doublet was displaced to the center of the axoneme as it left the basal body.

Metachromatic Reaction of Pancreatic B Cells to Toluidine Blue; Influence of pH on Staining

The granules of islet B cells show an intense β metachromasia when paraffin sections of pancreas fixed in Bouins fluid or formalin are dipped for 1 min in a 0.1% aqueous solution of toluidine blue O2 buffered to pH 6.0 with acetate or phosphate. This reaction provides a quick method for surveying the condition of B cells in experimental work. A weak staining is observable at pH 4.5 and becomes distinct at pH 5.5–6.0. Oxidation of sections (0.25% KMnO4 in 0.5% H2SO4, for 1 min, recommended) prior to staining intensifies the metachomatic reaction conspicuously. The metachromatic substance could not be demonstrated after fixation in either ethanol or acetone. It corresponds to the aldehyde fuchsin-positive and pseudoisocyanin-metachromatic substance in its occurrence and distribution in the B cells, as shown by different physiological states of various animals, including fasted and glucose-administered guinea pigs. It is thought to be topographically coincident but not necessarily identical to insulin.

Intercellular junctions between macrophages in the regional lymph node of the rat after injection of large doses of steroids

SummaryIntercellular junctions were often found between macrophages in sinuses of regional lymph nodes of the rat after injection of large doses of cholesterol, cortisone acetate, and estrone at the footpad. They were identified by subplasmalemmal densities, 20–50 nm in width, beneath the plasma membranes of apposed macrophages. No distinct filamentous structures were visible in those dense regions. Electron-dense amorphous materials are lined up at the center of the intercellular space in the junctional regions. Some macrophages form clusters with intercellular junctions. No significant difference in the effect of cholesterol, cortisone acetate, and estrone on the number of intercellular junctions betwene macrophages was found.

Mast cells and histamine in a newt, Triturus pyrrhogaster Boié.

Es wird nachgewiesen, dass die Mastzellen vonTriturus pyrrhogaster Boié kein Histamin enthalten, sie also im Gegensatz zur allgemeinen Annahme keine Histamozyten sind. Dieser Befund wurde sowohl biologisch am Meerschweinchendarm durch Extraktion des Histamins mit Hilfe der Codeschen Methode als auch durch den histochemischen Histaminnachweis mito-Phthalaldehyd an verschiedenen Geweben bestätigt.

Luxol Fast Blue Mbs and Phloxine; a Stain for Mitochondria

The applicability of Luxol fast blue MBS as a 0.1% solution in 0.05% acetic acid to the staining of mitochondria, first recognized in rat kidney by Shanklin and Nassar (Stain Techn., 34: 257-60. 1959), was confirmed in various organs (formalin-Zenker and Regauds fixations; paraffin embedding) of the mouse and bullfrog. In liver cells and in the epithelium of renal tubules, mitochondria were stained green, selectively and clearly. The dark cells of the renal tubules and the middle piece of sperms in both animals were conspicuously demonstrated by their dense assemblages of green granules. The periodic acid-Schiff procedure proposed by Shanklin and Nassar as a counterstain was replaced by staining in 0.5% aqueous phloxine, 2-3 min; differentiation in 5% phosphotungstic acid, 2 min; and washing in water, 5 min. This simplified and accelerated the techique, and gave a better color contrast. Advantages of Luxol fast blue MBS and phloxine staining over traditional methods for mitochondria in paraffin sections ...

Uptake of released mast cell granules by reticular cells of the rat lymph node

SummaryGranules released from mast cells were examined by electron microscopy in regional lymph nodes of rats after the injection of a large dose of horseradish peroxidase (HRP). Thirty minutes after the injection, a large number of mast-cell granules were present in sinuses, most of which adhered to the surfaces of reticular cells and some to macrophages. Two hours after the injection, a number of granules had been taken up by both reticular cells and macrophages. Reticular cells took up more granules than macrophages. Twenty-four hours after the injection, granules were scarce in both types of cells and in the extracellular space. Reticular cells surely participate in dealing with released mast-cell granules in the lymph node. Fibronectin bound to all mastcell granules was demonstrated by immunohistochemistry. Fibronectin probably enables negatively charged mast-cell granules to approach negatively charged cell surfaces to be taken up by both reticular cells and macrophages.

Vacuoles in macrophages and reticular cells of regional lymph nodes of the rat after injection of large doses of steroids.

SummaryThe ultrastructure of macrophages and reticular cells of regional lymph nodes of the rat after administration of large doses of cortisone acetate, estrone, progesterone, and cholesterol in aqueous suspensions was investigated. A large number of vacuoles, most of which were surrounded by unit membrane, and lipid droplets not surrounded by unit membrane were observed in the cytoplasm of both macrophages and reticular cells. They were not seen in these cells of control animals and in experimental animals that had received smaller doses of these steroid hormones. After cholesterol injection, many lipid droplets were observed in the cytoplasm of macrophages. These observations suggest that steroids injected in suspension accumulate in macrophages and reticular cells of the regional lymph nodes. Electron-dense material was often present in vacuoles of macrophages but not in those of reticular cells.

Changes of vitamins A and E in the rat retina under light and dark conditions detected with TOF-SIMS

Abstract Vitamin A is a key material for visual function and its metabolism is always important topics in visual sciences. TOF-SIMS (SIMS: secondary ion mass spectrometry) can detect organic materials and elements in relation to the cell and tissue. Changes of vitamin A distribution in the rat retina under light and dark adaptations were detected with TOF-SIMS. Vitamin A is present in combination with polyunsaturated fatty acids in the living cell. Vitamin E participates in the membrane stability. Thus we examined not only vitamin A, but also vitamin E. In light condition, vitamins A and E were increased in the photoreceptor cell. These findings suggest that these vitamins are increased in the light exposed retina.