Mutagenicity of cadmium, platinum and rhodium compounds in cultured mammalian cells.

The induction of mutation by cadmium chloride (CdCl2), platinum tetrachloride (PtCl4), and rhodium trichloride (RhCl3.3H2O) was measured utilizing the hypoxanthine-guanine phosphoribosyl transferase (HGPRT) locus in V-79 cells. Cadmium chloride at a concentration of 0.05 microM induced ford mutation in V-79 cells 4 times that of their control mutation frequency. Platinum tetrachloride at a concentration of 15 microM and 300 microM rhodium trichloride also induced ford mutation in V-79 cells at rates of around 7 and 4 times control rates, respectively. Platinum is often, and rhodium sometimes added to dental metallic alloys to improve their metallurgic characteristics and cadmium has been mingled in such alloys as well. Moreover, metallic dental drugs such as K2PtCl4 are used a dentine desensitizers. Thus, the genetic hazards of metal ions including cadmium, platinum, and rhodium that dissolve from dental materials and drugs must be investigated and caution exercised for their safe use in dental clinics.

[Pulmonary Tuberculosis in foreigners].

We studied the background and social problems of pulmonary tuberculosis in foreigners which we recently encountered at the National Chiba- Higashi Hospital and the Chiba Anti-tuberculosis Association. 1) The number of foreigners with pulmonary tuberculosis has been increasing year by year, one in 1983, none in 1984 and 1985, one in 1986, two in 1987 and four in 1988. 2) Most of these patients had been already infected or had some symptoms before their arrival to Japan. 3) Their background includes some serious social problems such as troubles in daily life coming from linguistic and cultural differences and economic difficulties, legal problems such as illegality of their stay in Japan, etc. 4) Most of the above cases could not be treated sufficiently because they are foreigners or because of their illegal stay.