We are developing new protein probes for in vivo radionuclide imaging using HaloTag® interchangeable labeling system. The selective and rapid bond formation between the HaloTag protein and HaloTag ligands can be applied to a more sophisticated labeling method for protein probes as a substitute of avidin–biotin interaction. For this purpose, we propose to use HaloTag-fusion proteins, which comprise targeting domain and HaloTag domain. In this study, we synthesized 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid (DOTA)–HaloTag ligands that could chelate radioactive metals useful for in vivo imaging. DOTA–HaloTag ligands were actually labeled with 111In efficiently, and the labeled ligands were successfully conjugated to a POH protein, which is a protein probe designed for imaging of hypoxia inducible factor-1α activity. The obtained 111In-labeled HaloTag-POH protein probes actually accumulated in implanted tumors in mice, which were visualized by single photon emission computed tomography (SPECT).
A growth hormone deficiency is associated with increases in body fat. However, it currently remains unclear whether subcutaneous- or/and intra-abdominal adipose tissues are markedly elevated in dwarf obesity. Experiments were conducted on the spontaneous dwarf rats (SDRs) and normal Sprague-Dawley (SD) rats using an X-ray computed tomography scanner to determine body composition. A longitudinal study of aging was also conducted to track age-related changes in body composition using same animals.We succeeded to estimate the subcutaneous and intra-abdominal adipose tissue mass in rat by X-ray CT. SDRs demonstrated the dwarf obesity, but SDs did not. SDRs developed dwarf obesity due to the accumulation of subcutaneous-abdominal adipose tissue, but not intra-abdominal adipose tissue. Age-dependent increases in the abdominal adipose tissue were observed in both SDRs and SDs. However, age-dependent increases in intra-abdominal adipose tissue were greater than in subcutaneous-abdominal adipose tissue.
Expert Committee on next-generation gamma-ray spectrometry, Science and Engineering Committee, Japan Radioisotope Association was established September 2015 and now is working on several aspects of gamma-ray spectrometry. Main issues are to review current available gamma-ray spectroscopy software for high purity germanium detector. Our discussion covers wide range of specific aspects of gamma-ray spectroscopy e.g. peak search methods, area calculation and correction of cascade-sum effect. We also review new development about gamma-ray spectroscopy in worldwide. We also will conduct an experiment on the possibility of absolute measurement of sample activity measured by high purity germanium detector using only the nuclear decay chain data and a spectrum of the sample. Reference spectrum will be also collected and distributed to test comparability of current available gamma-ray spectroscopy software. In this article we present current status of our discussion and ask readers to make comments on them.
f Electrons in rare-earth compounds are basically localized at rare-earth ions, and carry various degrees of freedom categorized in magnetic dipoles, electric quadrupoles, and high-rank multipoles. Because of interactions with conduction electrons, f electrons provide characteristic physical properties; Kondo effect, competition or cooperation between magnetic and charge orbital ordering, etc. Examples of inelastic neutron scattering studies on determination of quantum states of f electrons, ordering, and elementary excitations originating from many-body interctions are introduced.