Keizo Tsuruhara

Ultracytochemical Demonstration of Phospholipids in the Surface Layer of the Guinea Pig Eustachian Tube

The surface layer, especially the extracellular mucous blanket, in the eustachian tube of adult guinea pigs, was preserved very effectively with an intravascular perfusion of twice diluted Karnovskys fixative following overnight incubation in the same fixative containing 1% tannic acid. Multilamellar bodies were observed in both mucous lining layers of the tube and the epithelial cells of its lining, but neither reticular nor lattice-like ultrastructures could be detected. Mucous blankets on the pharyngeal portion were composed of an electron-dense surface film and a hypophase. The hypophase was marked heterogenous, and it could hardly be observed on the isthmus. The enzymic digestive method using a purified phospholipase A2 was applied to the middle portion of the tube, and the reaction products, probably phospholipids, could be seen both on the surface film of the lining layers and around some of the dark inclusion bodies in the secretory cells. These findings suggest that such phospholipids may play an important role in reducing surface tension of the eustachian tube.

Colchicine‐induced Inhibition of Fat Globule Development in Hepatocytes of Rats Injected with Ethionine

To examine the effect of colchicine on ethionine induced fatty liver, adult female rats were starved overnight and then injected i.p. with 1 g kg ethionine at 11th hour of fasting; then a half of the rats were also injected i.p. with 2.5 mg kg colchicine twice at 3 and 6 h after the single administration of ethionine. Similarly, fasted control rats were injected i.p. with vehicle alone at the above times. All of the rats were sacrificed after a 20 h fast, and the hepatocytes in periportal areas were observed ultra‐structurally. In addition, total lipids in the liver tissue were extracted and determined biochemically. Although similar significant increases of triglyceride were observed in the liver tissue of all ethionine‐injected rats, the hapatocytes in the group treated with both chemicals had fewer cytoplasmic fat globules (CFG) than those in the group treated with ethionine only. On the other hand, the diameters of markedly increased membrane‐bound lipid particles (MLP) in the double treated group were distributed mainly in the range 0.2–0.4 μm, compared with those (0.1‐0.2 μm) in the other groups. These findings indicate that colchicine inhibits the development of CFG in ethionine injured hapatocytes. Acta Pathol Jpn 39: 281∼288, 1989.

The Determination of Phospholipids in Middle Ear Effusion from Experimental Otitis Media in the Chinchilla

Phospholipid types were clarified both in eustachian tube secretion (ETS) and middle ear effusions (MEEs) from chinchilla middle ear. ETS was obtained from normal healthy animals and from animals with experimentally induced purulent otitis media (POM). MEE was obtained from experimentally induced serous and purulent otitis media (SOM and POM). In normal ETS, phosphatidylcholine (36.4%) was predominant followed by phosphatidylethanolamine (30.6%), sphingomyelin (18.0%), phosphatidylinositol (7.2%), phosphatidylglycerol (8.8%) and phosphatidylserine (2.5%). A significant loss of phosphatidylcholine was observed in ETS and MEE from experimentally induced otitis media. These findings suggest that both POM and SOM might be caused by a relative decrease of phospholipids, which is a major component of surfactants. Furthermore, the analysis of phospholipids in MEE may yield baseline information necessary to specify the factors responsible for chronicity or the tendency of recurrence of otitis media.