Shield, Anchor, and Adhesive Roles of Methylene Blue in Tyrosinase Adsorbed on Carbon Felt for a Flow Injection Amperometric Enzyme Biosensor for Phenolic Substrates and Inhibitors.

Methylene blue (MB) acted as a stabilizer for preventing surface-induced denaturation of tyrosinase (TYR) adsorbed on a carbon felt (CF) surface, which is based on shield and anchor roles preventing the unfavorable conformational change of TYR on the hydrophobic CF surface. Furthermore, MB acted as an effective adhesive for TYR immobilization on CF. The resulting TYR and MB coadsorbed CF (TYR/MB-CF) worked as an excellent working electrode unit in an electrochemical detector in a flow injection amperometric biosensor, which allowed highly sensitive consecutive determination of not only TYR substrates but also competitive inhibitors. Simultaneous adsorption of TYR and MB from their mixed solution was much useful as compared with step-wise separated adsorption of TYR on the MB-adsorbed CF, which suggests that the binding interaction of MB with TYR in the solution phase is important for this phenomenon. Fluorescence and UV-vis spectroscopy revealed that not only electrostatic forces between the cationic MB and anionic amino acid residues of TYR but also hydrophobic interactions via the phenothiazine ring of MB play a principal binding driving force of MB with TYR at the surface of the TYR molecules. Synchronous fluorescence, three-dimensional fluorescence, and circular dichroism (CD) spectroscopy clarified that the conformation and the secondary structure of TYR slightly changed upon the MB binding, implying that MB binding leads to the modification of the original intramolecular bonding in part.

Ibuprofen gargle for chemo- or Chemoradiotherapy-induced Oral Mucositis: a feasibility study.

BACKGROUND: Oral mucositis frequently occurs in cancer patients treated with chemotherapy and chemoradiotherapy (CRT). This study examined the safety and efficacy of ibuprofen gargle in healthy volunteers and patients with chemotherapy- and concomitant CRT-induced oral mucositis. METHODS: We enrolled healthy volunteers and patients with chemotherapy- and CRT-induced oral mucositis. In cohort I, single and multiple doses of ibuprofen gargle (0.6% or 1.0%) were administered to healthy volunteers on day 1 and days 4-10. In cohort II, multiple doses of ibuprofen gargle (0.6%) were administered to patients with complicated grade 2-3 oral mucositis based on the Common Terminology Criteria for Adverse Events (CTCAE) version 4.0. The primary endpoint of cohort I was the treatment-related adverse events (TRAEs) as defined by CTCAE version 4.0. The primary endpoint of cohort II was the change in the visual analogue scale (VAS) pain score from before to 15 min after gargle use on day 3. The incidence and severity of TRAEs were assessed based on the CTCAE version 4.0 and a subjective rating scale completed by healthy volunteers and patients. RESULTS: In cohort I, 9 of 10 healthy volunteers were evaluable for safety. All 9 healthy volunteers reported the TRAE of oral irritation with single or multiple use of the gargle. In cohort II, 10 patients were enrolled and evaluable for safety and 7 of 10 patients were evaluable for efficacy. The mean change in the VAS pain score from before to 15 min after using the gargle on day 3 was - 1.28 (95% confidence interval: - 2.06, - 0.51), and all patients experienced some degree of pain relief (range: - 0.2 to - 2.5). All 10 patients reported the TRAE of oral irritation. No other TRAEs of ibuprofen gargle were observed in the healthy volunteers and patients. CONCLUSION: Despite oral irritation, the ibuprofen gargle appeared to be safe and effective for the pain related to chemo- or CRT-induced oral mucositis. However, ibuprofen-related oral irritation warrants further formulation improvement. TRIAL REGISTRATION: This study was registered with the University Hospital Medical Information Network Clinical Trials Registry (UMIN000014433).

Flavan-3-ol/Procyanidin Metabolomics in Rat Urine Using HPLC-Quadrupole TOF/MS.

SCOPE: Several studies have demonstrated that flavan-3-ol/procyanidins are associated with biological functions in the prevention of various chronic diseases, including obesity and diabetes. Knowledge of their mechanisms, including bioavailability, has significantly progressed in the last decade. However, the differences of the metabolic signatures among flavan-3-ol/procyanidins remain ambiguous. METHODS AND RESULTS: The metabolites in urine over time after acute administration of three typical flavan-3-ol/procyanidins ((epi)catechin [EPC], epigallocatechin gallate [EGCG], and procyanidin dimer [PC]) in view of the chemical structure were analyzed by HPLC-quadrupole TOF/MS. Several bile acid and amino acid derivatives including tryptophan and tyrosine, as well as flavan-3-ol/procyanidin conjugates and phenolic acid degradation products generated by the gut microbiota were observed in rat urine. CONCLUSION: Multivariate statistical analyses suggest that the exogenous and endogenous metabolites of flavan-3-ol/procyanidins greatly differ, although the chemical structures of three typical flavan-3-ol/procyanidins-EPC, EGCG, and PC-are similar. Thus, metabolomic differences likely affect their biological functions and health benefits.