Fluorescence properties of pyrene derivative aggregates formed in polymer matrix depending on concentration

We investigated the fluorescence properties of dye aggregates formed in a poly(vinylalcohol) (PVA) matrix by phase separation. Trimethyl-(2-oxo-2-pyrene-1-yl-ethyl)-ammonium bromide (PyAm) was used as a fluorescent dye molecule. The size of PyAm aggregates in the PVA thin films were increased with increasing dye concentration, which was confirmed by atomic force microscope (AFM) measurements. The fluorescence spectra of PyAm in the PVA film at a lower concentration of 0.001 mol% only showed the monomer emission. The fluorescence peak shifted to the red with increasing dye concentration, which was assigned to a dimer or excimer-like emission. Changes in the fluorescence spectra relate to the formation of aggregates in the films. The fluorescence anisotropy decay time constant increases with increasing PyAm concentration up to the order of 100 ps. It is suggested that the exciton efficiently diffuses within the aggregates, and then was trapped at the dimer sites. We also demonstrated the application for gas sensing of nitroaromatics: 2,4-dinitrotoulene (DNT) based on the fluorescence quenching by the photoinduced electron transfer. The quenching efficiency of PyAm fluorescence reached about 43% under concentration of 2.0 mol%. The fluorescence intensity efficiently quenched at the dimer or excimer-like band. These results indicated that the efficient fluorescence quenching increases the reaction probability between PyAm and DNT by the exciton diffusion in the aggregates, called "amplified quenching''. The nano-sized aggregates of PyAm formed in the PVA films are responsible for high sensitivity as an artificial fluorescent chemosensor for vapors of the nitroaromatics.ArticlePHYSICAL CHEMISTRY CHEMICAL PHYSICS. 12(36):10923-10927 (2010)journal articl

PD-L1 expression combined with microsatellite instability/CD8+tumor infiltrating lymphocytes as a useful prognostic biomarker in gastric cancer

While the importance of programmed death-ligand 1 (PD-L1), mutation burden caused by microsatellite instability (MSI), and CD8+ tumor infiltrating lymphocytes (TILs) has become evident, the significance of PD-L1 expression on prognosis still remains controversial. We evaluated the usefulness of combined markers of PD-L1 and MSI or CD8+ TILs as a prognostic biomarker in gastric cancer. A total of 283 patients with gastric cancer were reviewed retrospectively. PD-L1 expression on >5% tumor cells was defined as PD-L1-positive. PD-L1-positive rate was 15.5% (44/283). PD-L1 positivity was significantly correlated with invasive and advanced cancer and also significantly correlated with MSI, whereas no significance was observed with CD8+ TILs. Kaplan-Meier analysis showed that PD-L1 positivity significantly correlated with a poor prognosis (p = 0.0025). Multivariate analysis revealed that PD-L1 positivity was an independent poor prognostic factor (hazard ratio [HR]: 1.97, p = 0.0106) along with diffuse histological type and lymph node metastases. Combinations of PD-L1 and MSI (HR: 2.18) or CD8+ TILs (HR: 2.57) were stronger predictive factors for prognosis than PD-L1 alone. In conclusion, combined markers of PD-L1 and MSI or CD8+ TILs may be more useful prognostic biomarkers in gastric cancer, and better clarify the immune status of gastric cance

Impact of plasma 5-hydroxyindoleacetic acid, a serotonin metabolite, on clinical outcome in septic shock, and its effect on vascular permeability

Septic shock is characterized by dysregulated vascular permeability. We hypothesized that the vascular permeability of endothelial cells (ECs) would be regulated by serotonin via serotonin-Rho-associated kinase (ROCK) signaling. We aimed to determine the impact of 5-hydroxyindoleacetic acid (5-HIAA) on septic shock as a novel biomarker. Plasma 5-HIAA levels and disease severity indices were obtained from 47 patients with sepsis. The association between 5-HIAA levels and severity indices was analyzed. Permeability upon serotonin stimulation was determined using human pulmonary microvascular ECs. 5-HIAA were significantly higher in septic shock patients than in patients without shock or healthy controls (p = 0.004). These elevated levels were correlated with severity indexes (SOFA score [p < 0.001], APACHE II [p < 0.001], and PaO2:FiO2 [p = 0.02]), and longitudinally associated with worse clinical outcomes (mechanical ventilation duration [p = 0.009] and ICU duration [p = 0.01]). In the experiment, serotonin increased the permeability of ECs, which was inhibited by the ROCK inhibitor (p < 0.001). Serotonin increases vascular permeability of ECs via ROCK signaling. This suggests a novel mechanism by which serotonin disrupts endothelial barriers via ROCK signaling and causes the pathogenesis of septic shock with a vascular leak. Serotonin serves as a novel biomarker of vascular permeability

Anti-integrin αvβ6 autoantibodies in patients with primary sclerosing cholangitis

[Background] Patients with primary sclerosing cholangitis (PSC) possess autoantibodies against biliary epithelial cells. However, the target molecules remain unknown. [Methods] The sera of patients with PSC and controls were subjected to enzyme-linked immunosorbent assays to detect autoantibodies using recombinant integrin proteins. Integrin αvβ6 expression in the bile duct tissues was examined using immunofluorescence. The blocking activity of the autoantibodies was examined using solid-phase binding assays. [Results] Anti-integrin αvβ6 antibodies were detected in 49/55 (89.1%) patients with PSC and 5/150 (3.3%) controls (P < 0.001), with a sensitivity and specificity of 89.1% and 96.7%, respectively, for PSC diagnosis. When focusing on the presence or absence of IBD, the proportion of the positive antibodies in PSC with IBD was 97.2% (35/36) and that in PSC alone was 73.7% (14/19) (P = 0.008). Integrin αvβ6 was expressed in bile duct epithelial cells. Immunoglobulin (Ig)G from 15/33 patients with PSC blocked integrin αvβ6-fibronectin binding through an RGD (Arg–Gly–Asp) tripeptide motif. [Conclusions] Autoantibodies against integrin αvβ6 were detected in most patients with PSC; anti-integrin αvβ6 antibody may serve as a potential diagnostic biomarker for PSC

Identification of an Anti–Integrin αvβ6 Autoantibody in Patients With Ulcerative Colitis

指定難病「潰瘍性大腸炎」の自己抗体発見 --新たな診断や治療開発へ--. 京都大学プレスリリース. 2021-03-09.Background and Aims: Ulcerative colitis is the most frequent type of inflammatory bowel disease and is characterized by colonic epithelial cell damage. Although involvement of autoimmunity has been suggested in ulcerative colitis, specific autoantigens/antibodies have yet to be elucidated. Methods: Using 23 recombinant integrin proteins, we performed enzyme-linked immunosorbent assays on sera from patients with ulcerative colitis and controls. Integrin expression and IgG binding in the colon tissues of patients with ulcerative colitis and controls were examined using immunofluorescence and coimmunoprecipitation, respectively. The blocking activity of autoantibodies was examined using solid-phase binding and cell adhesion assays. Results: Screening revealed that patients with ulcerative colitis had IgG antibodies against integrin αvβ6. In the training and validation groups, 103 of 112 (92.0%) patients with ulcerative colitis and only 8 of 155 (5.2%) controls had anti–integrin αvβ6 antibodies (P < .001), resulting in a sensitivity of 92.0% and a specificity of 94.8% for diagnosing ulcerative colitis. Anti–integrin αvβ6 antibody titers coincided with ulcerative colitis disease activity, and IgG1 was the major subclass. Patient IgG bound to the integrin αvβ6 expressed on colonic epithelial cells. Moreover, IgG of patients with ulcerative colitis blocked integrin αvβ6–fibronectin binding through an RGD (Arg-Gly-Asp) tripeptide motif and inhibited cell adhesion. Conclusions: A significant majority of patients with ulcerative colitis had autoantibodies against integrin αvβ6, which may serve as a potential diagnostic biomarker with high sensitivity and specificity

Potentiometric Titration Based on the Reference Electrode Equipped with Ionic Liquid Salt Bridge — 1. Precipitation Titration of Chloride with Silver Ions in Water

A reference electrode equipped with ionic liquid salt bridge consisting of tributyl(2-methoxyethyl)phosphonium bis(pentafluoroethanesulfonyl)amide has been employed for potentiometric precipitation titration of chloride with silver ions in water at 25 °C. A model for the titration curve was regressed to experimental curves, taking into account the change in the activity coefficients of relevant ionic species in the course of the titration, to obtain the least square estimates of two adjustable parameters in the model, the solubility product (Ksp) and the analyte concentration. The least-square estimate of Ksp, (1.840 ± 0.060) × 10−10, i.e., pKsp = 9.736 ± 0.014, is in good agreement with literature data, but with higher precision