Me-too validation study for in vitro skin irritation test with a reconstructed human epidermis model, KeraSkin™ for OECD test guideline 439.

We conducted a me-too validation study to confirm the reproducibility, reliability, and predictive capacity of KeraSkin™ skin irritation test (SIT) as a me-too method of OECD TG 439. With 20 reference chemicals, within-laboratory reproducibility (WLR) of KeraSkin™ SIT in the decision of irritant or non-irritant was 100%, 100%, and 95% while between-laboratory reproducibility (BLR) was 100%, which met the criteria of performance standard (PS, WLR≥90%, BLR≥80%). WLR and BLR were further confirmed with intra-class correlation (ICC, coefficients >0.950). WLR and BLR in raw data (viability) were also shown with a scatter plot and Bland-Altman plot. Comparison with existing VRMs with Bland-Altman plot, ICC and kappa statistics confirmed the compatibility of KeraSkin™ SIT with OECD TG 439. The predictive capacity of KeraSkin™ SIT was estimated with 20 reference chemicals (the sensitivity of 98.9%, the specificity of 70%, and the accuracy of 84.4%) and additional 46 chemicals (for 66 chemicals [20 + 46 chemicals, the sensitivity, specificity and accuracy: 95.2%, 82.2% and 86.4%]). The receiver operating characteristic (ROC) analysis suggested a potential improvement of the predictive capacity, especially sensitivity, when changing cut-off (50% → 60-75%). Collectively, the me-too validation study demonstrated that KeraSkin™ SIT can be a new me-too method for OECD TG 439.

Structure-activity relationship of human glutaminyl cyclase inhibitors having an N-(5-methyl-1H-imidazol-1-yl)propyl thiourea template.

In an effort to design inhibitors of human glutaminyl cyclase (QC), we have synthesized a library of N-aryl N-(5-methyl-1H-imidazol-1-yl)propyl thioureas and investigated the contribution of the aryl region of these compounds to their structure-activity relationships as cyclase inhibitors. Our design was guided by the proposed binding mode of the preferred substrate for the cyclase. In this series, compound 52 was identified as the most potent QC inhibitor with an IC50 value of 58 nM, which was two-fold more potent than the previously reported lead 2. Compound 52 is a most promising candidate for future evaluation to monitor its ability to reduce the formation of pGlu-Aß and Aß plaques in cells and transgenic animals.

A Study on the Psychological Attributes of Survivors Who Experienced Downsizing in China.

This study aims to examine how perceived justice affects downsizing survivors' attitudes, from the psychological contract perspective. By using data collected through surveys from employees of the Industrial and Commercial Bank of China (ICBC) who have recently survived layoffs, we examine the relationships between perceived justice, the survivors' psychological status, and their attitudes after downsizing. The hypothesis was verified through path analysis using SPSS 26.0 and Amos 23.0. Our findings are as follows. Perceived justice has a negative effect on psychological contract violation and a positive effect on trust. Psychological contract violation influences affective commitment negatively and influences turnover intention positively. Trust is positively related to affective commitment and negatively related to turnover intention. We hope that this study will be a useful piece of data that can provide guidelines for inducing positive behavior of members in downsized organizations.

Metformin Facilitates Amyloid-ß Generation by ß- and γ-Secretases via Autophagy Activation.

The evidence of strong pathological associations between type 2 diabetes and Alzheimer's disease (AD) has increased in recent years. Contrary to suggestions that anti-diabetes drugs may have potential for treating AD, we demonstrate here that the insulin sensitizing anti-diabetes drug metformin (Glucophage®) increased the generation of amyloid-ß (Aß), one of the major pathological hallmarks of AD, by promoting ß- and γ-secretase-mediated cleavage of amyloid-ß protein precursor (AßPP) in SH-SY5Y cells. In addition, we show that metformin caused autophagosome accumulation in Tg6799 AD model mice. Extremely high γ-secretase activity was also detected in autophagic vacuoles, apparently a novel site of Aß peptide generation. Together, these data suggest that metformin-induced accumulation of autophagosomes resulted in increased γ-secretase activity and Aß generation. Additional experiments indicated that metformin increased phosphorylation of AMP-activated protein kinase, which activates autophagy by suppressing mammalian target of rapamycin (mTOR). The suppression of mTOR then induces the abnormal accumulation of autophagosomes. We conclude that metformin, an anti-diabetes drug, may exacerbate AD pathogenesis by promoting amyloidogenic AßPP processing in autophagosomes.

Inhibition of glutaminyl cyclase ameliorates amyloid pathology in an animal model of Alzheimer's disease via the modulation of γ-secretase activity.

Alzheimer's disease is the most prevalent neurodegenerative disorder, characterized by neurofibrillary tangles, senile plaques, and neuron loss. Amyloid beta peptides are generated from amyloid beta precursor protein by consecutive catalysis by ß and γ-secretases. Diversely modified forms of A have been N3pE-42 Aß has received considerable attention as one of the major constituents of the senile plaques of AD brains due to its higher aggregation velocity, stability, and hydrophobicity compared to the full-length A. A previous study suggested that is catalyzed by glutaminyl cyclase (QC) following limited proteolysis of Aß at the N-terminus. Here, we reveal that decreasing the QC activity via application of a QC inhibitor modulates-γ-secretase activity, resulting in diminished plaque formation as well as reduced N3pE 42 Aß aggregates in the subiculum of the 5XFAD mouse model of AD. This study suggests a possible novel mechanism by which QC regulates Aß formation , namely modulation of γ-secretase activity.

The control of invasive Candida infection in very low birth weight infants by reduction in the use of 3rd generation cephalosporin.

PURPOSE: To evaluate the effectiveness of new management policies on the incidence of invasive Candida infections. METHODS: This observational study involved a retrospective analysis of the patients' medical records. In total, 99 very low birth weight infants, who were admitted to the neonatal intensive care unit at Ajou University Hospital from January 2010 to December 2011, were enrolled for the study. Period I, defined as the period before the revision of management policies, comprised 57 infants; whereas, period II, defined as the period after the implementation of new management policies, comprised 42 infants. The new management policies entailed a reduction in antibiotic and histamine type 2 receptor blocker (H2 blocker) use, duration of central venous catheterization, and duration of endotracheal intubation. RESULTS: There was a significant overall decrease in the use of antibiotics including 3rd generation cephalosporin and H2 blockers (P<0.05), and a significantly lower incidence of invasive Candida infections in period II as compared to period I (0/42 vs. 6/57, respectively; P=0.037). Comparison between infants with invasive Candida infections (n=6) and those without (n=93) showed that gestational age (odds ratio [OR], 0.909; 95% confidence interval [CI], 0.829 to 0.996; P=0.042) and the duration of 3rd generation cephalosporin use (OR, 1.093; 95% CI, 1.009 to 1.183; P=0.029) were statistically significant risk factors. CONCLUSION: The new management policies effectively decreased overall use of antibiotics, especially 3rd generation cephalosporin, and H2 blockers, which led to a significantly lower incidence of invasive Candida infections.

Effective screen for amyloid ß aggregation inhibitor using amyloid ß-conjugated gold nanoparticles.

The abnormal aggregation of amyloid ß (Aß) and its subsequent intra- and extracellular accumulation constitute the disease-causing cascade of Alzheimer's disease (AD). The detection of Aß aggregates and senile plaque formation, however, is nearly impossible during early pathogenesis, and the absence of a convenient screen to validate the activity of Aß aggregation regulators impedes the development of promising drug targets and diagnostic biomarkers for AD. Here, we conjugated amyloid ß42 (Aß42) peptide to gold nanoparticles (AuNPs) to visualize Aß42 aggregation via Aß42 aggregation-induced AuNP precipitation. AuNP-Aß42 precipitate was quantified by optical density measurements of supernatants and thioflavin T binding assay. Transmission electron microscopy (TEM) analysis also showed reduced interparticle distance of AuNPs and confirmed the Aß42 aggregation-induced AuNP precipitation. Transthyretin, a widely known Aß aggregation inhibitor, limited AuNP-Aß42 precipitation by preventing Aß42 aggregation. Finally, according to TEM analysis, Aß42-conjugated AuNPs treated with blood-driven serum revealed the differentiated aggregation patterns between normal and AD. These findings may open a scientific breakthrough in finding a possible diagnostic and prognostic tool for neurodegenerative diseases involving abnormal protein aggregation as their key pathogenesis processes.