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In this review, I present the main highlights of my works in the development of bioelectrocatalysis, which can be used in widespread applications, particularly for the design of biosensor and biofuel cells. In particular, I focus on research progress made in two key bioelectrocatalytic reactions: glucose oxidation by flavin adenine dinucleotide-dependent glucose dehydrogenase and oxygen reduction by bilirubin oxidase. I demonstrate the fundamental principles of bioelectrocatalysis and the requirements for enhancing the catalytic performance, including the choice of a mediator of redox reactions, immobilization, and electrode materials. These methods can allow for achieving control of the bioelectrocatalytic reaction, thereby overcoming obstacles toward their industrial applications.

Introduction: In rheumatoid arthritis (RA), P-glycoprotein (P-gp) expression on activated B cells is associated with active efflux of intracellular drugs, resulting in drug resistance. CXCR4 is associated with migration of B cells. This study was designed to elucidate the relevance of P-gp expression on CXCR4 + B cells to clinical manifestations in refractory RA., Methods: CD19 + B cells were analyzed using flow cytometry and immunohistochemistry., Results: P-gp was highly expressed especially on CXCR4 + CD19 + B cells in RA. The proportion of P-gp-expressing CXCR4 + B cells correlated with disease activity, estimated by Simplified Disease Activity Index (SDAI), and showed marked expansion in RA patients with high SDAI and extra-articular involvement. In highly active RA, massive infiltration of P-gp + CXCR4 + CD19 + B cells was noted in CXCL12-expressing inflammatory lesions of RA synovitis and RA-associated interstitial pneumonitis. In RA patient with active extra-articular involvement, intracellular dexamethasone level (IDL) in lymphocytes diminished with expansion of P-gp + CXCR4 + CD19 + B cells. Adalimumab reduced P-gp + CXCR4 + CD19 + B cells, increased IDL in lymphocytes, and improved the clinical manifestation and allowed tapering of concomitant medications., Conclusions: Expansion of P-gp + CXCR4 + B cells seems to be associated with drug resistance, disease activity and progressive destructive arthritis with extra-articular involvement in RA.

It is often difficult to manage refractory gastrointestinal tract complications of Behçet's disease (entero-BD) by conventional therapy. In this study, we assessed the short- and long-term efficacy and safety of the combination therapy of infliximab, an anti-tumor-necrosis-factor (TNF)-α antibody, and methotrexate in ten patients with refractory entero-BD refractory to conventional therapies. The short- (weeks) and long-term (by 2 years) effects of infliximab at 3-5 mg/kg body weight every 8 weeks on the clinical course and intestinal manifestations were assessed by abdominal computed tomography (CT) and colonoscopy. The primary endpoint was the rate of disappearance of ileocecal ulceration at 12 months of therapy. All patients showed improvement of gastrointestinal symptoms and disease-associated complications within 4 weeks. Furthermore, the rate of disappearance of ileocecal ulcerations was 50% (5/10 patients) at 6 months and 90% (9/10 patients) at 12 months, and, therefore 90% of patients were satisfied with the primary endpoint. Furthermore, corticosteroid dose was significantly reduced from 22.0 to 1.8 mg/day at 24 months. No severe adverse effects were observed during the 24 months of follow-up. We provide evidence for the rapid and excellent efficacy of infliximab in patients with refractory entero-BD and that the combination of infliximab and methotrexate brings about long-term alleviation of entero-BD and excellent tolerability.

Histamine dehydrogenase from Nocardioides simplex (HmDH) which catalyzes the oxidative deamination of histamine is an iron-sulphur-containing flavoprotein. For our further understanding on the intramolecular electron transfer process, the reductive half reaction of HmDH with histamine has been studied by stopped flow spectrophotometry at pH 7.5 and 10. The reaction at pH 7.5 is found to be analysed on a kinetic model composed of three sequential first-order reactions. The first fast phase, of which the rate constant shows a hyperbolic dependence on the histamine concentration, is assigned to a direct two-electron reduction of the oxidized flavin (CFMN(O)) by histamine with no involvement of the semiquinone form of the flavin (CFMN(S)). The second moderate process is the substrate-independent intramolecular single-electron transfer from the reduced flavin to the oxidized iron-sulphur cluster. The third slow process is considered to reflect the second binding of histamine to CFMN(S), which is responsible for the substrate inhibition. At pH 10, the reaction is analysed with one pseudo-first-order reaction phase which is substrate-dependent two-electron reduction of CFMN(O) coupled with the subsequent fast intersubunit single-electron transfer. The UV-vis spectroscopy of HmDH suggests the deprotonation of Tyr residues, which seems to cause the switching of the electron transfer property.

P-glycoprotein (P-gp) on activated lymphocytes is an adenosine triphosphate (ATP)-binding cassette transporter that causes drug resistance by exclusion of intracellular drugs in patients with active rheumatoid arthritis (RA). However, infliximab with methotrexate (MTX) can overcome P-gp-mediated drug resistance. We encounter patients who cannot continue infliximab or MTX. Here we tested how etanercept affected P-gp-mediated drug resistance in such intractable RA patients. Peripheral lymphocytes of 11 RA patients (3 switched from infliximab and 8 who could not be treated with MTX) were analyzed for P-gp expression by flow cytometry and for drug exclusion using radioisotope-labeled dexamethasone. Activated lymphocytes of RA patients overexpressed P-gp and coexpressed CD69. Incubation of these lymphocytes with dexamethasone in vitro reduced intracellular dexamethasone levels. Two-week etanercept therapy significantly reduced P-gp expression and eliminated such P-gp- and CD69-high-expressing subgroup. The reduction in P-gp resulted in recovery of intracellular dexamethasone levels in lymphocytes and improvement of disease activity, thus allowing tapering of corticosteroids. None of the patients experienced any severe adverse effects. Etanercept is useful for overcoming P-gp-mediated treatment resistance in intractable RA patients who have to discontinue infliximab or are intolerant to MTX.

Objective: Combined paclitaxel and carboplatin is a standard regimen for inoperable non-small cell lung cancer (NSCLC). Although an every-3-week schedule is common, weekly paclitaxel is clinically effective for various cancers. A Phase I clinical trial was conducted to determine maximum-tolerated doses (MTDs) for weekly combined paclitaxel and carboplatin, and to evaluate anti-tumor response, toxicity and pharmacokinetics of paclitaxel in patients with inoperable NSCLC., Methods: Twenty patients with inoperable NSCLC received weekly carboplatin at area under the curve (AUC) = 2 mg/ml min and paclitaxel. Paclitaxel was escalated if MTD was not reached. Three patients each were entered at levels 1 and 2 (level 1, paclitaxel 50 mg/m(2) and carboplatin AUC = 2 mg/ml min; level 2, 60/2), six at level 3 (70/2), five at level 4 (80/2) and three at level 5 (90/2)., Results: One patient had grade 4 (G4) neutropenia at level 2, one had G3 hepatic toxicity at level 3 and one had G3 cardiac toxicity at level 4. MTD was not reached for all dose levels. Response rate (RR) was 35% (7/20) and median survival was 11.1 months. Severe neutropenia (G3 and G4) was seen in seven patients associated with greater AUC, peak concentration (C(max)) and the duration of plasma concentration >50 ng/ml of paclitaxel., Conclusions: Weekly combined paclitaxel (up to 90 mg/m(2)) and carboplatin (AUC = 2 mg/ml min) was well tolerated. A higher dose intensity of paclitaxel can be given, and RR and survival are not less than the every-3-week protocol. The weekly regimen is an alternative for untreated inoperable NSCLC patients.

Objective: Interstitial pneumonia (IP) associated with CTDs often progresses despite conventional immunosuppressive treatment. We investigated the efficacy of human urinary trypsin (UT) inhibitor (ulinastatin) on refractory IP., Methods: Five patients with IP received UT inhibitor (3 x 10(5) U) infusion into the internal jugular vein, three times in a single day. The response to this therapy was assessed clinically and by chest CT, PaO(2) and serum KL-6. The kinetics of UT inhibitor was determined in arterial blood. We measured serum levels of monocyte chemotactic protein-1 and TGF-beta1, which are thought to be involved in the pathogenesis of IP., Results: Serum concentrations of UT inhibitor increased immediately to >150 U/ml after infusion of 3 x 10(5) U of UT inhibitor. The treatment resulted in clinical and radiological improvements in four patients, and allowed reduction of oxygen therapy following improvement of hypoxaemia within 1 month. UT inhibitor decreased serum levels of KL-6 in all patients and had no adverse effects. MCP-1 and TGF-beta1 concentrations were higher in the patients than in normal subjects, and infusion of 3 x 10(5) U of UT reduced the concentrations within 3 h of infusion., Conclusion: UT inhibitor bolus infusion therapy is a potentially useful therapeutic strategy for intractable IP based on the different mechanism of action relative to conventional immunosuppressive therapy and lack of serious treatment-related adverse effects.

Histamine dehydrogenase from Nocardioides simplex is a homodimer and belongs to the family of iron-sulfur flavoproteins having one [4Fe-4S] cluster and one 6-S-cysteinyl FMN per monomer. In the reductive titration with histamine, two-electron reduction occurred per monomer at pH<9, while single-electron reduction proceeded at pH>9. The substrate-reduced histamine dehydrogenase yielded an electron paramagnetic resonance spectral signal assigned to the flavin semiquinone. The signal intensity increased with pH up to pH 9 and reached a maximum at pH>9. These unique features are explained in terms of the redox potential of the cofactors, where the redox potential was evaluated over a pH range from 7 to 10 by using a spectroelectrochemical titration method for the flavin and cyclic voltammetry for the [4Fe-4S] cluster. The bell-type pH dependence of the enzymatic activity is also discussed in terms of the pH dependence of the centers' redox potential.

A novel FAD-dependent glucose dehydrogenase (FAD-GDH) was found and its enzymatic property for glucose sensing was characterized. FAD-GDH oxidized glucose in the presence of some artificial electron acceptors, except for O2, and exhibited thermostability, high substrate specificity and a large Michaelis constant for glucose. FAD-GDH was applied to an amperometric glucose sensor with Fe(CN)6(3-) as a soluble mediator. The use of a relatively high concentration of Fe(CN)6(3-) resulted in a good linearity between the current response and the glucose concentration, taking into account a large Michaelis constant for Fe(CN)6(3-). The glucose sensor was completely insensitive to O2 and responded linearly to glucose up to 30 mM. Compared to glucose, the response to other saccharides was negligible. The sensor can be stored at room temperature in a desiccator for at least one month without any change in the response or activity.

Objectives: Systemic lupus erythematosus (SLE) is an autoimmune disease characterized by autoreactive T cells and polyclonally activated B cells that produce autoantibodies. Five SLE patients who failed to respond to conventional immunosuppressants were treated with anti-CD20 antibody (rituximab) and their clinical manifestations and laboratory data were evaluated, including phenotypic analysis of B cells., Methods: Rituximab (375 mg/m(2)) was administered weekly for 2 weeks in five SLE patients who developed severe manifestations despite intensive treatment., Results: Rituximab resulted in rapid improvement (within several days) in clinical manifestations such as consciousness disorder, seizures, progressive sensory disorder, haemolytic crisis, cardiac function and laboratory data. The effects lasted 20 months in one patient; other patients were in remission for more than 6 months. Flow cytometric analysis revealed down-regulation of CD40 and CD80 expression on CD19-positive B cells 1 week after infusion of rituximab, and such down-regulation was seen for more than 7 months in two patients., Conclusions: Our pilot study provides sufficient evidence of excellent tolerability and high efficacy of rituximab therapy in refractory SLE. Rituximab not only reduced B-cell number and IgG levels but down-regulated CD40 and CD80 on B cells, suggesting possible disturbance of T-cell activation through these costimulatory molecules. Reduction of both quantity and quality of B cells suggests that rituximab could improve the disease course in patients with refractory SLE.

P-glycoprotein (P-gp) expels various drugs from cells, resulting in multidrug resistance, including against glucocorticoids. Here, we present a case of systemic lupus erythematosus (SLE) that suggests the importance of initial intensive treatment in overcoming unresponsiveness due to P-gp overexpression on activated lymphocytes. A 28-year-old woman had been diagnosed with highly active SLE including severe pericarditis, hemolytic anemia, lupus nephritis, and retinopathy. The disease activity of SLE progressed despite 1 mg/kg per day oral prednisolone. At the time, P-gp expression was extremely high, as evaluated by flow cytometric analysis on peripheral lymphocytes. After intensive treatment with three courses of methylprednisolone pulse therapy and plasmapheresis, we succeeded in controlling disease activity in association with marked reduction of P-gp overexpression; namely, the clinical symptoms immediately improved along with the reduction of P-gp expression. These results imply that patients with highly active SLE might have drug unresponsiveness that is mediated by P-gp overexpression on lymphocytes. Therefore, downregulation of P-gp by initial intensive immunosuppressive therapy might be important for overcoming glucocorticoid resistance. We also propose that measurement of P-gp on lymphocytes is a useful test for prediction of drug resistance and may assist in the selection of appropriate initial treatment.

Interstitial pneumonia (IP) with mixed connective tissue disease (MCTD) often progresses despite immunosuppressive therapies that caused serious infections. Human urinary trypsin inhibitor (UT) inhibits inflammatory factors associated with IP, without immunosuppression. UT bolus infusion rescued a female MCTD patient with refractory IP and severe opportunistic fungal pneumonia. Her IP diminished with monthly UT bolus infusion despite tapering of prednisolone, without UT-related side effects. UT pulse therapy could prove beneficial for refractory IP in MTCD even with opportunistic infections.

Objectives: We evaluated the polymerase chain reaction (PCR) detection of Pneumocystis carinii DNA in induced sputum of patients with connective tissue diseases and assessed the clinical features of patients positive for P. carinii., Methods: Sputum was induced by nebulization in 29 in-patients with various connective tissue diseases who presented with symptoms suggestive of P. carinii pneumonia (PCP), and was examined by PCR., Results: Detection of P. carinii DNA by PCR was significantly more sensitive than cytology; 54.5% patients were positive by PCR and only 4.5% by cytology. The prevalence of PCP was higher than previously considered and was especially high in patients receiving > 30 mg/day prednisolone with or without other immunosuppressants. P. carinii-positive patients had significant lymphocytopenia and a low serum IgG level compared with P. carinii-negative patients. P. carinii disappeared within 7-10 days after therapy with trimethoprim/sulfamethoxazole., Conclusion: We propose that the use of PCR for detection of P. carinii using induced sputum is a useful and non-invasive method that has high sensitivity and specificity for the early diagnosis of PCP.

Abstract The aim of this study was to evaluate the efficacy and safety of mizoribine in patients with Sjögren's syndrome. Forty patients with sicca syndrome, whose conditions were definitely diagnosed as Sjögren's syndrome, were given mizoribine orally at a dosage of 150 mg/day for 12 months. The percentage change in salivary secretion after 3, 6, and 12 months of the therapy increased to +112.2% (P < 0.001), +119.9% (P < 0.01), and +147.3% (P < 0.001), respectively, compared with the baseline. Serum IgG levels decreased significantly throughout the study, and the level was 1969.4 ± 620.0 mg/dl after treatment for 12 months compared with the pretreatment value of 2094.3 ± 746.6 mg/dl (P < 0.05). The patient's assessment of clinical signs and symptoms on a 10-cm visual analog scale improved significantly from 7.2 ± 2.3 cm at the start of the treatment to 5.0 ± 1.9 cm after 12 months (P < 0.001). There was a similar improvement in the physician's assessment using the 10-cm visual analog scale: 7.1 ± 1.6 cm at the start of the treatment and 5.2 ± 1.9 cm after 12 months (P < 0.001). With regard to safety, no serious adverse reactions were observed. Although a controlled study would be required to clarify the efficacy of mizoribine, these preliminary observations indicate its efficacy for ameliorating glandular symptoms through improvements in immune abnormalities in patients with Sjögren's syndrome.