The study of biomineralization represents a realm of sharing among diverse scientific fields such as crystallography, mineralogy, biology, paleontology, and medical sciences. The processes of normal and pathological biomineralization are determined by three factors : precurser, mediator, and inhibitor. Amorphous and hydrated phases being soluble and unstable are found as precursors of biominerals. An organic matrix acts as a mediator in biomineralization permitting a rate of nucleation even at lower supersaturation-levels, and having the function to determine the growth, structure, and orientation of mineral particles. Inhibitor plays a role to regulate mineral deposition and is likely to be decomposed at the sites where mineralization is provoked.

抄録全体を表示

The crystallization processes of cholesterol gallstones were analysed by a close examination of the thin sections of spherulitic gallstones. An experimental observations of growth and agglomeration of cholesterol monohydrate single crystals were carried out using a biological phase-contrast microscope. On the basis of these experiments, the formation processes of cholesterol gallstones were proposed.

抄録全体を表示

About the static organ and the statolith of various animals, the existence and its place, the morphology and the crystal structure were reviewed. Statoliths in goldfish were observed in situ. The shape changed during the growth from the sphere to the shape which followed the statocyst. The statolith was a polycrystal of CaCO₃ with aragonite structure and its maximum growth rate was 0.84A/s. The degree of supersaturation of endolymph in which the statoliths grew was estimated to be 11.4. The growth of statolith in vivo was compared with that of CaCO₃ crystal in vitro.

抄録全体を表示

Asbestos and many other fibrous minerals are extremely important materials for our modern industrialized society to keep it safely and comfortable. However, the adverse health effect of asbestos, especially its carcinogenecity, has been revealed during recent 15 years. In this symposium paper, the author reviewed 1) definition of asbestos because the term can not be defined by mineralogy, 2) diseases due to the exposure of asbestos, such as asbestosis, lung cancer, and mesothelioma as well as synergism effect of asbestos exposure and cigarette smoking, 3) current problems of asbestos in Japan, such as asbestos concentration in working environment controlled by current regulation, chances of asbestos exposure including general people, and 4) biological effect of asbestos substitutes, especially in referece to the cases of mesothelioma due to fibrous erionite in Turkey and the hyposesis by Drs. Stanton and Pott. In conclusion, we should consider now how to cope with asbestos and other mineral fibers safely for our life.

抄録全体を表示

The relationship between the concentration and characteristics of air contaminants in the work place and potential hazards after their inhalation depends greatly on their patterns of depositions and the rates and pathways for their clearance from the deposition sites . Exposure values for dust containing crystalline silica have been based on the quantitative concept that the magnitude of the toxicity is proportional to the concentration of crystalline silica in the respirable dust.Preventive measures for pneumoconiosis divide into following 2 branches . (1) Medical control and management including guidance for livelihood, replacement, rest, treatment and education. (2) Environmental control including monitoring, emission control, isolation of hazardous process. Mineralogy has played an important role in both branches of the protective procedure. This review presents the knowledge on lung dust, cytotoxicity and fibrogenetic activity of minerals and control procedures for pneumoconiosis from viewpoint of mineralogists.

抄録全体を表示