Polonium-210 (Po-210) is considered to be one of the most poisonous radionuclides by food ingestion. However, analytical methods for detection of Po-210 remain controversial. Therefore, we explored practical methods for measuring Po-210 that are applicable to various foods. The pretreatment procedures were evaluated using a wide range of foods. Direct electrodeposition onto a stainless steel disc yielded recovery (93–113
Recently, health hazards, such as kidney damage, have been reported owing to the ingestion of a health food product, so-called “foods with functional claims (FFC)’’, containing beni-koji (red yeast rice). Although not an expected compound in the FFC, the detection of puberulic acid has also been reported. Further investigations of these health food products, such as the identification of other unintended compounds and clarifying the health impacts of puberulic acid, are required. To clarify the causes of these health issues, we investigated the presence of unintended compounds in the FFC containing beni-koji using comprehensive instrumental analyses. Using differential analysis, novel compounds 1 and 2 were detected as unexpected components between the samples with and without adverse event reports. Although limited to the samples available for analyses in this study, both compounds 1 and 2 were detected in all the samples that also contained puberulic acid. Compounds 1 and 2, with molecular formulas of C23H34O7 and C28H42O8, respectively, may be lovastatin derivatives. Their structures were confirmed using NMR analyses and are novel natural compounds. For definitive confirmation, we are in the process of synthesizing compounds 1 and 2 from lovastatin. The route of contamination of these compounds are currently under investigation. The findings of this study could be used to address the growing health hazards associated with health food products.
X-ray computed tomography (XRCT) allows for non-destructive three-dimensional observation and volumetric quantification of samples. It also allows for structural changes monitoring, such as the amorphous-to-crystalline transition in pharmaceuticals, over time. Despite past applications of XRCT to characterize amorphous pharmaceuticals, its quantitative validity has not been systematically verified against established thermal methods. Here, we evaluated laboratory XRCT for monitoring the crystallization behavior of amorphous acetaminophen and validated its accuracy via differential scanning calorimetry (DSC). In XRCT, amorphous content was determined from voxel-based phase segmentation, while DSC estimates were obtained from the specific heat change at the glass transition temperature. Time-dependent crystallization at 30°C was quantified using XRCT followed immediately by DSC, showing strong correlation (R2 = 0.990). These results demonstrated that XRCT provides a reliable, voxel-based measure of amorphous fraction, despite the limited precision imposed by the micrometer-scale spatial resolution. XRCT enables continuous monitoring of a single sample—from preparation through near-complete crystallization—and reduces the number of samples required to construct crystallization profiles. In situ XRCT enabled visualization of the initial sites of detectable crystallization and its spatial propagation within the sample, revealing information unattainable from bulk thermal analysis. Herein, phase-retrieval image processing improved phase discrimination, although the processing effect could be influenced by sample type or experimental conditions. The XRCT method is proposed not for precise quantification, but as a practical and efficient tool for rapid screening of physical stability, formulation development, and assessment of storage conditions in early-stage pharmaceutical development.
Immunoglobulin G (IgG) is a multifunctional glycoprotein essential for immune defense and widely used as a therapeutic due to its antigen specificity and effector functions. However, the inherent flexibility of its hinge region complicates structural characterization and obscures the molecular basis of its mechanism of action. To clarify the hinge’s role, we performed systematic amino acid substitutions. Notably, deletion of Pro230 led to the formation of a half-IgG1 species lacking inter-heavy chain interactions. Structural analysis using nuclear magnetic resonance (NMR), negative-stain EM, and disulfide bond quantification by LC-MS/MS peptide mapping revealed the mechanism underlying half-IgG1 generation. To enable this, we developed a new stable-isotope labeling method for NMR. Functional assays with FcγR-expressing reporter cells demonstrated that half-IgG1 retained selective FcγRI-mediated activity. These findings provide new insights into higher-order IgG structure and Fcγ receptor-dependent immune activation, offering a basis for designing next-generation antibody therapeutics.
As Nature Aging celebrates its fifth anniversary, the journal asks some of the researchers who contributed to the journal early on to reflect on the past and the future of aging and age-related disease research, the impact of the field on human health now and in the future, and what challenges need to be addressed to ensure sustained progress.
