In silico experiments of bone remodeling explore metabolic diseases and their drug treatment.

Bone structure and function are maintained by well-regulated bone metabolism and remodeling. Although the underlying molecular and cellular mechanisms are now being understood, physiological and pathological states of bone are still difficult to predict due to the complexity of intercellular signaling. We have now developed a novel in silico experimental platform, V-Bone, to integratively explore bone remodeling by linking complex microscopic molecular/cellular interactions to macroscopic tissue/organ adaptations. Mechano-biochemical couplings modeled in V-Bone relate bone adaptation to mechanical loading and reproduce metabolic bone diseases such as osteoporosis and osteopetrosis. V-Bone also enables in silico perturbation on a specific signaling molecule to observe bone metabolic dynamics over time. We also demonstrate that this platform provides a powerful way to predict in silico therapeutic effects of drugs against metabolic bone diseases. We anticipate that these in silico experiments will substantially accelerate research into bone metabolism and remodeling.

Simple determination of (99)Tc in radioactive waste using Tc extraction disk and imaging plates.

A simple method was developed for determination of (99)Tc in low-level radioactive waste: Technetium-99 retained by a solid phase extraction disk was directly measured with imaging plates system. It was found that more than 97% of Tc were retained by the disk from a solution of pH 2 to 12, whereas depth profile of Tc in the disk, which greatly influences the counting efficiency, depended on solution pH. The present method was successfully applied to actual radioactive liquid waste samples arising from nuclear research facilities.

[Automated assay method for protein C anticoagulant activity].

We developed an automated assay method for protein C anticoagulant activity to prolong the APTT measured with automated coagulation apparatus. The automated assay method required following three reagents. One was 0.025 mol/l calcium chloride solution. The other two were a protein C deficient plasma and a phospholipid plus protein C activator both of which constituted a recomposed protein C assay kit (BMY). 0-50% activities of protein C and clotting times were regressed on normal linear curve, while 25-150% activities and clotting times were regressed on logarithmic curve. The coefficients of variation were 2.9-3.4% (intra-assay) and 3.6-3.9% (inter-assay). A correlation of protein C activities between measured by automated assay method and by ordinary manual method was good (r = 0.954). Our data suggest that this automated assay is a useful method for measuring the protein C anticoagulant activities utilizing a coagulation apparatus.