Rapid and Convenient Single-Chain Variable Fragment-Employed Electrochemical C-Reactive Protein Detection System.

Although IgG-free immunosensors are in high demand owing to ethical concerns, the development of convenient immunosensors that alternatively integrate recombinantly produced antibody fragments, such as single-chain variable fragments (scFvs), remains challenging. The low affinity of antibody fragments, unlike IgG, caused by monovalent binding to targets often leads to decreased sensitivity. We improved the affinity owing to the bivalent effect by fabricating a bivalent antibody-enzyme complex (AEC) composed of two scFvs and a single glucose dehydrogenase, and developed a rapid and convenient scFv-employed electrochemical detection system for the C-reactive protein (CRP), which is a homopentameric protein biomarker of systemic inflammation. The development of a point-of-care testing (POCT) system is highly desirable; however, no scFv-based CRP-POCT immunosensors have been developed. As expected, the bivalent AEC showed higher affinity than the single scFv and contributed to the high sensitivity of CRP detection. The electrochemical CRP detection using scFv-immobilized magnetic beads and the bivalent AEC as capture and detection antibodies, respectively, was achieved in 20 min without washing steps in human serum and the linear range was 1-10 nM with the limit of detection of 2.9 nM, which has potential to meet the criteria required for POCT application in rapidity, convenience, and hand-held detection devices without employing IgGs.

[Bone Marrow Carcinomatosis with Disseminated Intravascular Coagulation in a Breast Cancer Patient Treated with Chemotherapy and CDK4/6 Inhibitor].

We report a case of a breast cancer patient with bone marrow carcinomatosis and disseminated intravascular coagulation who was treated with chemotherapy and a CDK4/6 inhibitor. The patients, a 68-year-old woman, presented to our hospital with anorexia and was found to have multiple liver metastases of breast cancer. Furthermore, she had anemia and thrombocytopenia, and a bone marrow biopsy showed bone metastasis of the breast cancer. Therefore, a diagnosis of bone marrow carcinomatosis and disseminated intravascular coagulation was made. Treatment was started with chemotherapy(epirubicin and cyclophosphamide)and subsequently changed to an aromatase inhibitor(letrozole)and a CDK4/4 inhibitor(abemaciclib) and was maintained without exacerbation of the patient's condition.

Changes in Polyamine Content in Rice Bran due to Fermentation with Aspergillus oryzae Analyzed by LC/ESI-MS/MS Combined with Derivatization.

Many studies have demonstrated that the dietary supplementation of polyamines, especially spermidine (SPD), prevents age-related diseases. Rice bran is rich in polyamines and their amounts could be increased by fermentation with Aspergillus oryzae (A. oryzae). In this study, we developed a method for the determination of putrescine (PUT), SPD and spermine (SPM) in rice bran samples by liquid chromatography/electrospray ionization-tandem mass spectrometry (LC/ESI-MS/MS) after derivatization with 4-(N,N-dimethylaminosulfonyl)-7-fluoro-2,1,3-benzoxadiazole (DBD-F). The derivatization improved the LC retention and ESI-MS/MS detectability of the polyamines, and consequently enabled precise and accurate quantification. Using this method, we found that the SPD content increased to 158% due to fermentation with A. oryzae, while the content of PUT and SPM decreased. SPD is known as the polyamine playing a central role in cell proliferation and growth, and therefore has health benefits. The fermented rice bran might be a good material for functional foods aimed at SPD supplementation.

A Method for Simultaneous Determination of 25-Hydroxyvitamin D3 and Its 3-Sulfate in Newborn Plasma by LC/ESI-MS/MS after Derivatization with a Proton-Affinitive Cookson-Type Reagent.

A method for the simultaneous determination of 25-hydroxyvitamin D3 [25(OH)D3] and its 3-sulfate [25(OH)D3S] in newborn plasma, which is expected to be helpful in the assessment of the vitamin D status, using stable isotope-dilution liquid chromatography/electrospray ionization-tandem mass spectrometry (LC/ESI-MS/MS) has been developed and validated. The plasma was pretreated based on the deproteinization and solid-phase extraction, then subjected to derivatization with 4-(4-dimethylaminophenyl)-1,2,4-triazoline-3,5-dione (DAPTAD). The derivatization enabled the accurate quantification of 25(OH)D3 without interference from 3-epi-25(OH)D3 and also facilitated the simultaneous determination of the two metabolites by LC/positive ESI-MS/MS. Quantification was based on the selected reaction monitoring with the characteristic fragmentation of the DAPTAD-derivatives during MS/MS. This method was reproducible (intra- and inter-assay relative standard deviations of 7.8% or lower for both metabolites) and accurate (analytical recovery, 95.4-105.6%). The limits of quantification were 1.0 ng/mL and 2.5 ng/mL for 25(OH)D3 and 25(OH)D3S, respectively, when using a 20-µL sample. The developed method was applied to the simultaneous determination of plasma 25(OH)D3 and 25(OH)D3S in newborns; it was recognized that the plasma concentration of 25(OH)D3S is significantly higher than that of 25(OH)D3, and preterm newborns have lower plasma 25(OH)D3S concentrations than full-term newborns.

Development and validation of a method for determination of plasma 25-hydroxyvitamin D3 3-sulfate using liquid chromatography/tandem mass spectrometry.

The quantification of plasma 25-hydroxyvitamin D3 3-sulfate [25(OH)D3S] is expected to be helpful in the assessment of the vitamin D status, especially for infants. In this study, a simple and sensitive method for the quantification of 25(OH)D3S in plasma using liquid chromatography/electrospray ionization-tandem mass spectrometry (LC/ESI-MS/MS) has been developed and validated. The plasma was deproteinized with acetonitrile, purified using an Oasis(®) HLB cartridge, and subjected to LC/ESI-MS/MS operating in the negative-ion mode. Quantification was based on the selected reaction monitoring, and deuterated 25(OH)D3S was used as the internal standard. This method enabled the reproducible (intra- and inter-assay relative standard deviations, 7.9% or lower) and accurate (analytical recovery, 95.8-105.3%) quantification of the plasma 25(OH)D3S using a 20-µL sample, and the limit of quantification was 2.5ng/mL. The developed method was applied to the determination of plasma 25(OH)D3S in infants; the result revealed that preterm infants have lower plasma 25(OH)D3S concentrations.