Yoichi Masumitsu

Glycoconjugates in the Otholithic Organ of the Developing Chick Embryo

The presence of glycoconjugates in the otolithic organ of developing chick embryos was investigated histochemically using lectins. On the 6-day-old chick embryo, intense labelling with lectins was observed in the sensory epithelium, on the surface of the epithelium and on the immature otoconia. The otoconia were intensely labelled with lectins at every stage of the chick embryos, while the labelling with lectins in the sensory epithelium became weaker with the maturing of the otoconia. In TEM observation, the secretory granules of the supporting cells of the sensory epithelium were labelled with lectin. The reaction of lectin was more intense in the electronic dense zone of the otoconium than in the electronic lucent zone at every stage of the chick embryos. These findings indicate that the precursors of the otoconia are secreted by the supporting cells of the sensory epithelium and that glycoconjugates play an important role in otoconial formation.

Effects of carbonic anhydrase inhibitor on the otolithic organs of developing chick embryos

Carbonic anhydrase appears to be involved in the process of otoconial formation. The purpose of this investigation was to observe the morphologic change in the surface structure of the otolithic organ in developing chick embryos after injection of the carbonic anhydrase inhibitor, acetazolamide. Acetazolamide (1.5, 3, or 6 mg/0.06 mL/egg) was injected into the yolk sac of the embryo of the fifth day of incubation. Embryo specimens were collected on the 11th, 13th, and 18th days of incubation. The chicks were killed on the third day posthatching, and the surfaces of the otolithic organs were observed under a scanning electron microscope. A marked disturbance in otoconial formation was noted in both utricle and saccule, marked by a decrease or absence of otoconia. A widely exposed meshwork structure of otolithic membrane was observed, with sensory cilia penetrating the meshwork small holes in many instances. There were also several otoconial abnormalities, such as the appearance of only a single giant otoconium, or from several to dozens of giant otoconia, and rough, spongy-surfaced global substances entirely covering the maculae. Clearly, carbonic anhydrase inhibitor (acetazolamide) injected into the yolk sac of developing chick embryos alters and inhibits normal otoconial morphogenesis.

Light and Electron Microscopic Features of the Rat Vestibular Ganglion Cells

The vestibular ganglion cells of the rat were characterized with regard to the cytoplasmic structure by light and electron microscopic observation. Light microscopy revealed four types of cells, depending upon the characteristics and distribution of Nissl granules. Electron microscopy gave a definite classification of these types by the arrangement and distribution of the roughly surfaced endoplasmic reticulum and neurofilament. The characteristics of the ganglion cells are discussed in relation to their size and function.

Suppression by ticlopidine of peplomycin-induced pulmonary fibrosis; A clinical evaluation.

Peplomycin-induced pulmonary fibrosis disturbs unexpectedly and unfortunately the schedule of treatment with anti-cancer drugs. Recent pharmacological experiments in animals disclosed that ticlopidine may be useful in suppressing peplomycin-induced pulmonary fibrosis. We investigated clinically the suppression by ticlopidine of peplomycin-induced pulmonary fibrosis.Ticlopidine was administered orally to ten patients with head and neck cancer who were being treated with peplomycin, and its suppression of peplomycin-induced pulmonary fibrosis was evaluated by noting the changes in pulmonary fibrosis markers: angiotensin I converting enzyme (ACE), phospholipid (PL), malondialdehyde (MDA) and type III procollagen peptide (Type III p. p.) . Serum analysis showed no change in ACE, but PL increased significantly, indicating that ticlopidine can suppress peplomycininduced pulmonary fibrosis.

Evaluation of Internal Echo Histograms of Head and Neck Tumors. (II).

For the differential diagnosis of tumors, we studied the internal echo histograms of 20 head and neck tumors with a 7.5MHz probe; the width of the histograms was of 0%, 25%, 50%, 75% frequency and the echo level was of maximum shades of grey.1) An analysis of the width of the histograms showed three patterns: mountain type with a narrow base for normal tissue, mountain type with a wide base for benign tumors and bell type with wide base and sides for malignant tumors.2) There was no statistically significant difference in the echo level of the maximum shades of grey between benign and malignant tumors.