Yoshimi Teraki

Fine Structure of the Taste Bud in Guinea Pigs

The localization of spot 35 protein, a cerebellar Purkinje cell-specific protein, was studied in guinea pig taste buds by means of electron-microscopic immunocytochemistry. The immunoreactivity was localized in the cytoplasmic matrix of discrete bud cells. The ultrastructural features of the reactive cells indicated that they corresponded to the Type III or gustatory cells making a synaptic contact with the intragemmal nerves. All other cells specified as basal, Type I, and Type II were immunonegative for spot 35 protein. This finding indicates a method for specifically demonstrating the gustatory cells in the guinea pig taste bud and, further, gives new evidence that paraneurons may share neuron-specific substances with neurons.

Sensitive detection of trace aluminium in biological tissues by confocal laser scanning microscopy after staining wtih lumogallion

This paper describes a method for the sensitive detection of aluminium in biological tissues by real time confocal laser scanning microscopy after staining with lumogallion. The method enabled detection of aluminium > or = 9 micrograms g-1 in bone and is more sensitive than the conventional histochemical methods with aluminium and solochrome azurine, etc. Lumogallion reacts specifically with aluminium to form a fluorescent complex so that the proposed method is useful for detection and identification of aluminium in tissues.

Ultrastructure of Pleromin, a Highly Mineralized Tissue Comprizing Crystalline Calcium Phosphate Known as Whitlockite, in Holocephalian Tooth Plates

The gross structure and microstructure of holocephalian tooth plates were initially investigated by Bargmann (1,2) and Brettnacher (3). Orvig (4,5,6) subsequently reported in the detail microstructural characteristics of both extant and fossil holocephalian tooth plates. These studies indicate the holocephalian tooth plate to consist of bony tissue and hypermineralized pleromin (4), with the hardness of pleromin comparable to that of enamel and enameloid. Ishiyama et al. (7) found the crystalline material of pleromin to be not hydroxyapatite but whitlockite by a powder X-ray diffractometry, and pleromin to be the sole sound dental tissue consisting of whitlockite in vertebrates.

Chemical Properties of Metal Ions and Carcinogenesis

Publisher Summary This chapter discusses the carcinogenic potential of metal compounds and the mechanisms of metal carcinogenesis by referring to data obtained by mutagenicity tests in bacteria, the commonly used short-term screening procedures for carcinogenic metallic compounds, and by experimental findings in laboratory animals. The chapter discusses the findings regarding carcinogenesis of principal metallic compounds in laboratory animals and the underlying mechanisms. The chapter also discusses the results of some studies on the development of fibrosarcoma with lead acetate in the rat. Metal ions bind to constituents of the organism, especially to proteins or nucleic acids, thus giving rise to irreversible damage to the biologic function, which would lead to malignant change of affected cells. The metal ions with proven carcinogenic potential have all been shown to have mutagenic activity in bacteria. The metal ions show high degrees of affinity for proteins and nucleotide bases.