Radiation dose rates now and in the future for residents neighboring restricted areas of the Fukushima Daiichi Nuclear Power Plant.

Radiation dose rates were evaluated in three areas neighboring a restricted area within a 20- to 50-km radius of the Fukushima Daiichi Nuclear Power Plant in August-September 2012 and projected to 2022 and 2062. Study participants wore personal dosimeters measuring external dose equivalents, almost entirely from deposited radionuclides (groundshine). External dose rate equivalents owing to the accident averaged 1.03, 2.75, and 1.66 mSv/y in the village of Kawauchi, the Tamano area of Soma, and the Haramachi area of Minamisoma, respectively. Internal dose rates estimated from dietary intake of radiocesium averaged 0.0058, 0.019, and 0.0088 mSv/y in Kawauchi, Tamano, and Haramachi, respectively. Dose rates from inhalation of resuspended radiocesium were lower than 0.001 mSv/y. In 2012, the average annual doses from radiocesium were close to the average background radiation exposure (2 mSv/y) in Japan. Accounting only for the physical decay of radiocesium, mean annual dose rates in 2022 were estimated as 0.31, 0.87, and 0.53 mSv/y in Kawauchi, Tamano, and Haramachi, respectively. The simple and conservative estimates are comparable with variations in the background dose, and unlikely to exceed the ordinary permissible dose rate (1 mSv/y) for the majority of the Fukushima population. Health risk assessment indicates that post-2012 doses will increase lifetime solid cancer, leukemia, and breast cancer incidences by 1.06%, 0.03% and 0.28% respectively, in Tamano. This assessment was derived from short-term observation with uncertainties and did not evaluate the first-year dose and radioiodine exposure. Nevertheless, this estimate provides perspective on the long-term radiation exposure levels in the three regions.

Adhesion of tissue sections from eleven organs on glass slides with amino group coatings.

The adhesion of immunohistochemically stained tissue sections from eleven different organs on microscope slides was compared. Skin, trachea and mammary gland tissue sections heat-treated for antigen retrieval exhibited strong adhesive retention on glass slides coated with self-assembled monolayers containing amino groups at high density.

Quantification of hydroxyprolyl-glycine (Hyp-Gly) in human blood after ingestion of collagen hydrolysate.

Plasma levels of prolyl-hydroxyproline (Pro-Hyp) and hydroxyprolyl-glycine (Hyp-Gly) in healthy volunteers (n=5) after ingestion of collagen hydrolysate were estimated by liquid chromatography-tandem mass spectrometry. The ratio of Hyp-Gly to Pro-Hyp was distributed in the range of 0.063-0.221. This is a first report for quantification of food-derived Hyp-Gly in human plasma.

Breeding severely vitamin B12-deficient mice as model animals.

Newborn mice weaned from mice fed on a B12-deficient diet during pregnancy and lactation were fed on a B12-deficient diet for 90 days after weaning, and the state of B12 deficiency was evaluated. The effect of B12 deficiency on the testicular tissue was also examined. The body weight of the mice fed on a B12-deficient diet for 90 days was slightly lower than that of the control mice administrated CN-B12, and the urinary excretion of methylmalonic acid (MMA) was increased. The B12 concentrations in the liver and testes were markedly depressed by B12 deficiency, being about 13 and 10 pmol/g, respectively, on day 90. The testes weight was clearly reduced by B12 deficiency. The testes weight/100 g body weight was also lowered. Clear morphological changes were observed in the testicular tissue of the B12-deficient mice. These results showed that mice in a severely B12-deficient state could be produced by dietary B12 deprivation. These B12-deficient mice could be useful as model animals not only for elucidating the functions of B12 in vivo, but also for biochemical studies.