The understanding of human pharmacokinetics is important for development of new drugs. Microdosing studies have been proposed as means of obtaining human pharmacokinetics information at early stages of drug development. Accelerator mass spectrometry (AMS) has high detection sensitivity and is expected to play an important role in microdose trials. In this study, we used the AMS microdosing facility at Yamagata University to measure the concentration of 14C in 14C-oxaliplatin-spiked serum samples. The calibration curve of 14C concentration in serum was linear, and the correlation coefficient was 0.9994. The precision, accuracy, and stability values obtained (freeze and thaw cycles, and short- and long-term stability) satisfied the criteria. The mean background 14C concentrations in samples of 6 healthy Japanese volunteers were 1.635dpm/mL in blood and 0.56dpm/mL in plasma. These results suggest the suitability of AMS-based quantitation for analyzing samples from microdosing studies.
To detect γ-ray irradiation traces for foods, thermal chemiluminescence spectra of food packages were measured with a multichannel Fourier-transform chemiluminescence(FT-CL) spectrometer, where the irradiation dose was chosen in the range between 10Gy and 10kGy. It was found that the highest sensitivity for the γ-ray irradiation was ?? 10Gy dose, which was much better than that of the ESR method. In addition, the γ-ray irradiation traces of the samples were detectable after 14 months. It was confirmed that the FT-CL is useful as a screening method to detect γ-ray irradiation traces for foods.
We examined the effects of the heterogeneity of 137Cs concentration in soil on transferability to shallow rooted fig and non-shallow rooted grapes. Three-year-old trees were planted into the pots filled with soil changed to the concentration of radioactivity Cs in surface (0 - 5cm) and deep soil (5 - 15cm). Transfer rate of radioactive 137Cs to plants from the soil was higher in fig than in grapes when grown under the same conditions. In fig trees, transfer rate of radioactive 137Cs to plants from the soil was higher the plants cultivated under high concentration of 137Cs in surface soil than in deep soil.
At experimental field in Nishi-Tokyo City, we investigated the seasonal changes in radiocaesium concentration divided into bark and wood in peach lateral shoot during 16months from four months after the accident at Fukushima Daiichi Nuclear Power Plant. With the passage of season, the concentration of radiocaesium in bark tended to more decrease than natural attenuation. We compared concentration of radiocaesium with 40K, and considered that the dilution effect due to falling of the outer bark which had high concentration of radiocaesium was involved with that decrease.
The Subcommittee on Survey of Nuclear Medicine Practice in Japan has performed a nationwide questionnaire surveys every five years since 1982. The latest questionnaire survey was performed in June 2012. The estimated total number of the annual examinations was 1.15 millions, 19% less than that of the last survey in 2007. The scintigraphic examination most frequently performed was bone scintigraphy, followed by myocardial and brain perfusion scintigraphy in order. The number of PET studies and radionuclide targeted therapies increased by 40% and 62%, respectively, as compared to the 2007's survey. The increase was attributable to growing uses of commercially delivered FDG, and the newly started radionuclide targeted therapy for patients with metastatic bone tumor or malignant lymphoma, in addition to 131I therapy for patients with thyroid cancer or Graves' disease. The number of in vitro radioassays has been decreasing continuously since 1992.
Functions of heme proteins are finely tuned by the electronic and coordination structure of the heme (iron porphyrin complex) placed in the active site of protein. Therefore, it is quite important to reveal the physicochemical properties of a wide variety of synthetic model heme complexes for better understanding the functions and reaction mechanisms of heme proteins. The heme electronic structures have been determined by the combined analysis of NMR, ESR, Mössbauer, and IR spectrometry as well as SQUID(superconducting quantum interference device) magnetometry and X-ray crystallography. Specifically, two kinds of electronic ground states observed in low-spin iron(III) porphyrin complexes, i.e. commonly observed(dxy)2(dxz, dyz)3 and less common(dxz, dyz)4(dxy)1, as well as the novel spin crossover phenomena involving the intermediate-spin state are described. Special interest is the mono-imidazole complexes showing the spin crossover among all the possible spin states in iron(III) porphyrin complexes, i.e., S＝1/2, 3/2, and 5/2. The novel electronic structures mentioned above are recently pointed out to involve in the catalytic process of some naturally occurring heme proteins.