Mitsuo Machino

Wheat germ agglutinin binding sites in the organ of Corti as revealed by lectin-gold labeling

The distribution of wheat germ agglutinin(WGA)-binding sites in the organ of Corti of the guinea pig and mongolian gerbil was studied. WGA was conjugated with gold particles and applied on thin sections of the cochlea embedded in Spurrs resin and in Lowicryl K4M. WGA-binding sites were found on the plasma membrane, lysosomes and cytoskeletons of hair and supporting cells as well as on the tectorial and basilar membranes. No distinct difference was discovered between hair cells and supporting cells in terms of WGA-binding activities.

Cupulogenesis and glycoconjugates in the labyrinthine ampulla as revealed by WGA-gold labeling

SummaryWe studied the distribution of wheat germ agglutinin (WGA)-bindable glycoconjugates in the vestibular ampulla of mongolian gerbils. WGA was conjugated with gold particles and applied to Lowicryl K4M sections of the ampulla. WGA-binding sites were found on the cupula and some of the secretory granules and Golgi apparatuses in the supporting cells of the sensory epithelia. The granules were seen to secrete into the endolymphatic space through reticular membrane. It is likely, therefore, that glycoconjugates are glycosylated at the Golgi apparatus in the supporting cells, stored in the granules, and secreted through the reticular membrane into the endolymphatic space to be used as a component of the cupula. The cell membranes of various cells, connective tissue filaments in the perilymphatic space and the cytoplasm of melanocytes were also labeled with WGA-gold.

Localization of triphosphoinositide in the cochlea

SummaryTriphosphoinositide (TPI) has been demonstrated to be a receptor for aminoglycosides in the cochlea and may regulate ionic permeability by its binding with Ca++. This phospholipid was localized by a protein A-gold technique in the cochlea at the electronmicroscopic level. TPI was prepared by a neomycin column and antibodies to it were raised in rabbits. The antibody used in this study reacted virtually only to TPI among the tested lipids. TPI was localized mainly at stereocilia, cuticular plates, head plates of Deiters cells, plasma membrane, and mitochondria of various cells in the organ of Corti. In the vascular stria, TPI was found mainly at the plasma membrane of basal infoldings of the marginal cells. Possible physiological and pathophysiological roles of TPI in the cochlea are briefly discussed.

Polymyxin B binding sites in Escherichia coli as revealed by polymyxin B-gold labeling.

A complex of polymyxin B, bovine serum albumin, and colloidal gold was prepared and used for the ultrastructural localization of polymyxin B binding sites on thin sections of Epon-embedded Escherichia coli cells. Gold particles were found on the outer membrane of E. coli, which is consistent with reported biochemical findings. We concluded that gold labeling with polymyxin B is useful in localizing the binding sites of polymyxin.

Lysozyme producers in nasal mucosa. An immunocytochemical study.

The question of whether or not goblet cells in the nasal mucosa are lysozyme producers has yet to be examined. In the present study, lysozyme was localized by the protein A-gold technique in human nasal mucosa with special attention to goblet cells. Both light and electron microscopic immunostaining revealed lysozyme in the secretory granules of the goblet cells, although far less than the amount present in the serous cells of the nasal glands. We concluded that the nasal glands were the main producer and goblet cells the subsidiary producer of lysozyme in nasal mucosa.

Establishment and characterization of a carcinoembryonic antigen producing cell line derived from human pancreatic exocrine cancer

SummaryA human pancreatic carcinoma cell line derived from well differentiated tubular adenocarcinoma of the pancreas head has been established and maintained for nearly 4 years. This established cell line produces and releases carcinoembryonic antigen into the culture medium. The cell line grows as a monolayer in RPMI-1640 medium containing 10 percent fetal calf serum. Xenotransplantation in athymic nude mice after subcutaneous injection of EDTA-trypsin treated cells did not succeed.

Amylase secretion by nasal glands. An immunocytochemical study.

Amylase, an enzyme that hydrolyzes starch, has been localized in the nasal mucosa for the first time by the protein A-gold technique. The amylase appeared to be produced by serous cells of the nasal glands. This enzyme has the potential for use as a tumor marker for cancer of the nasal cavity. The function of amylase in the physiology of nasal secretions is discussed.

Immunocytochemical detection of triphosphoinositide in vestibular hair cells

SummaryTriphosphoinositide (TPI), an aminoglycoside receptor and a possible regulator of cationic permeation through its ability to bind with Ca++, was localized by the protein-A gold technique in vestibular sensory epithelia using an antibody highly specific to TPI. TPI was detected on the stereocilia, kinocilia, and cuticular plate of hair cells, and in the reticular membrane of supporting cells. The cilia of hair cells are damaged by aminoglycosides at a relatively early stage of toxicity. Ca++-regulated bioactivity in this area is probably involved.

Bacteriolytic Activity of Lysozyme in the Nasal Mucosa

During an experiment to study the localization of the lysozyme in the nasal mucosa of humans by the protein A-gold technique, we observed the accumulation of lysozymes around bacteria possibly causing bacteriolysis. The lysozyme, therefore, seems to play a preventive role against some kind of bacterial infection in the nasal mucosa in situ.

Experimental immune complex otitis media: localization of IgG by protein A-gold technique.

Immune complex (IC) was made of bovine serum albumin (BSA) and anti-BSA guinea pig serum, and instilled into the tubotympanic cavity of untreated guinea pigs. The location of IgG was determined by using the protein A-gold technique to trace IC in the tubotympanic mucosa of the otitis media with effusion (OME) caused by the instillation. IgG was found on the effusion, degenerated ciliated cells and on granules of goblet cells. There was no evidence of intense accumulation of IgG on the basement membrane of the mucosal epithelium or the capillaries. It is likely that IC activates complements in the tubotympanic cavity to cause OME.