Characteristic Evaluation of a C-Labeled Leucine Analog, l-α-[5-C]methylleucine, as a Tracer for Brain Tumor Imaging by Positron Emission Tomography.

Amino acid transporters are upregulated in many cancer cells, and system L amino acid transporters (LAT1-4), in particular, LAT1, which preferentially transports large, neutral, and branched side-chain amino acids, are considered a primary target for cancer positron emission tomography (PET) tracer development. Recently, we developed a C-labeled leucine analog, l-α-[5-C]methylleucine ([5-C]MeLeu), via a continuous two-step reaction of Pd-mediated C-methylation and microfluidic hydrogenation. In this study, we evaluated the characteristics of [5-C]MeLeu and also compared the sensitivity to brain tumors and inflammation with l-[C]methionine ([C]Met) to determine its potential for brain tumor imaging.

A novel (11)C-labeled thymidine analog, [(11)C]AZT, for tumor imaging by positron emission tomography.

Background: Nucleoside analogs labeled with positrons, such as (11)C and (18)F, are considered valuable in visualizing the proliferative activity of tumor cells in vivo using positron emission tomography (PET). We recently developed the (11)C-labeled thymidine analogs [(11)C]zidovudine ([(11)C]AZT) and [(11)C]stavudine ([(11)C]d4T) via the Pd(0)-Cu(I) co-mediated rapid C-C coupling reaction. In this study, to examine whether [(11)C]AZT and [(11)C]d4T might be useful for visualization of tumors in vivo, we performed PET imaging, tissue distribution studies, and metabolite analysis in tumor-bearing mice.

Optimal topotactic conversion of layered octosilicate to RWR-type zeolite by separating the formation stages of interlayer condensation and elimination of organic guest molecules.

We demonstrate that the separation of two stages of interlayer condensation under refluxing and elimination of organic guests provides the optimal conditions for the formation of RWR-type zeolite from layered octosilicate. The obtained RWR-type zeolite has higher quality than any other RWR-type zeolite reported previously.