Keiko Teramoto

Recovery process of tracheal mucosa of guinea pigs exposed to isopropyl alcohol

The toxicity of isopropyl alcohol (IPA) on the tracheal mucosa was studied experimentally with special reference to the recovery process of the organ. The results showed that 400 ppm IPA has an acute effect on the mucociliary system in the tracheal mucosa, and that recovery from such degeneration can occur in 2 weeks. When functional and morphological damage was induced by a higher level (5500 ppm) of IPA, recovery did not occur in 2 weeks. The conclusion is that the present allowable level of IPA is reasonable from the viewpoint of the effects of short-term exposure to IPA on the tracheal mucosa. In addition, a higher level of IPA exposure has longer-term effects on the tracheal mucosa, and workers exposed to such a higher level of IPA vapor should be given careful otolaryngological follow-up observations.

Toxicity of isopropyl alcohol exposure on the nasal mucociliary system in the guinea pig

The toxicity of isopropyl alcohol (IPA) on the nasal mucosa in the guinea pig was experimentally studied, with special reference to the recovery process of the organ. The results showed that 400 ppm of IPA has an acute effect on the nasal mucosa and the recovery from such degeneration can occur in 2 weeks. When functional and morphological damages were induced by a higher level (5500 ppm) of IPA, it took over 2 weeks for complete recovery from such damage. The conclusion is that the present allowable level of IPA is reasonable from a viewpoint of the effect of short-term exposure to IPA on the nasal mucosa. In addition, a higher level of IPA exposure has a longer-term effect on the nasal mucociliary system in the guinea pig, and workers exposed to such a higher level of IPA should be given careful otolaryngological observation.

Zinc Content in Japanese Food and Estimated Average Daily Intake

The zinc content of 284 types of 1, 693 food items commonly eaten by the Japanese was measured and a zinc content table was prepared based on the Food Standard Composition Table (4th edition). A good correlation was found between the values calculated using this table and the zinc content of 15 cooked meals. This table provides an estimate of the zinc intake in the average diet of Japanese people. Urban adult inhabitants were asked about the foods they had eaten using the 24-hour recall method and the average daily zinc intake was calculated to be 10.8 mg for males and 9.5 mg for females.

Effects of Styrene on Peripheral Nerve Conduction Velocities in Rats

Effects of Styrene on Peripheral Nerve Conduction Velocities in Rats: Tadashi Yamamoto, et al. Department of Preventive Medicine and Environmental Health, Osaka City University Medical School—The effects of styrene on the peripheral nerves were studied by measuring conduction velocities of the tail nerve in 24 male Wistar rats which had been exposed to 0 (control), 200 and 2,000 ppm of styrene (8 rats for each concentration) for 32 wk (8 h/dx5 d/wk), from the age of 8 wk, and in the same number of rats which received the same treatment since they were 4 wk of age. Motor nerve conduction velocity (MCV), distal latency (DL) and sensory nerve conduction velocity (SCV) were determined at 2‐wk intervals from the age of 8 wk to 16 wk after the end of exposure. Body weight in the 2,000 ppm (start at 4 and 8 wk of age) and 200 ppm (start at 4 wk of age) exposure groups were significantly lower than in the control group. MCV and DL in the all exposure groups were not significantly different from the control group. SCV in the 2,000 ppm (start at 4 and 8 wk of age) and 200 ppm (start at 8 wk of age) exposure groups were significantly lower than in the control group during the styrene exposure. After discontinuation of exposure, SCV remained small in the 2,000 ppm group (start at 4 wk) compared with that in the controls, but showed recovery in the other exposure groups. The effects on the decrease in SCV were greater in the distal than in the proximal area.

Simultaneous determination of bromine and chlorine in cow's milk by radioactivation analysis

Bromine and chlorine have been determined in cows milk by radioactivation analysis. These elements are adsorbed from irradiated samples on to silver hexacyanoferrate(II) Amberlite IRA 904 resin. The recovery from this resin is about 96% for both elements. The limit of detection is about 5 µg for bromine and about 1 mg for chlorine using a Van der Graaf accelerator and about 50 µg for bromine and 2 mg for chlorine using the Kinki University research reactor (thermal neutron flux of 1.5 × 107 n cm–2 s–1).The precision of the method is about ±10% for bromine and about ±20% for chlorine for concentrations exceeding 5 p.p.m.