Development and psychometric evaluation of the death risk perception scale for advanced cancer patients.

BACKGROUND: An accurate perception of death risk is a prerequisite for advanced cancer patients to make informed end-of-life care decisions. However, there is to date no suitable scale to measure death risk perception. This study was to develop and psychometrically test the death risk perception scale (DRPS) for advanced cancer patients. METHODS: Process of instrument development and psychometric evaluation were used. First, qualitative research, a literature review, brainstorming, a Delphi study, and cognitive interviews were conducted to construct a pretest scale of death risk perception. Second, a scale-based survey was administered to 479 advanced cancer patients. Item, exploratory factor, and confirmatory factor analyses were employed to optimize the scale. The Cronbach's alpha was calculated as a reliability analysis. The validity analysis included construct, convergent, discriminant, and content validity values. RESULTS: A three-dimension, 12-item scale was developed, including deliberative, affective, and experiential risk perception. The confirmatory factor analysis supported the three-factor model with satisfactory convergent and discriminant validity levels. The Cronbach's alpha coefficient for internal consistency was 0.807 and scale-level content validity index was 0.98. CONCLUSIONS: The 12-item DRPS is a reliable and valid instrument for assessing the level of death risk perception in advanced cancer patients. More studies are needed to examine its structure and robustness prior to use.

Expression and role of melatonin membrane receptors in the hypothalamic-pituitary-testicular axis of Tibetan sheep in a plateau pastoral area.

MTNR1A and MTNR1B, two high-affinity MT membrane receptors found in mammals, mediate the activity of MT on the HPGA to regulate animal reproduction. Nevertheless, the expression patterns and function of the MTNR1A and MTNR1B genes in the HPTA of seasonal estrus sheep and perennial estrus sheep have not been elucidated. We studied the expression of MTNR1A and MTNR1B in the hypothalamic-pituitary-testicular axis (HPTA) of Tibetan sheep at different reproductive stages using histochemistry, enzyme linked immunosorbent assay (ELSIA), scanning electron microscopy, transmission electron microscopy, quantitative Real-time PCR (qRT-PCR), and Western blot (WB), and analyzed the relationship between their expression and reproductive hormone receptors. We also compared relevant characteristics between seasonal Tibetan sheep and non-seasonal Small Tail Han sheep in the same pastoral area. The results showed that MTNR1A and MTNR1B were expressed in all tissues of the Tibetan sheep HPTA, and both were co-expressed in the cytoplasm of epididymis basal and halo cells located at common sites of the epididymis basement membrane, forming an immune barrier. The qRT-PCR analysis showed that not only MTNR1A but also N-acetyltransferase (AANAT), hydroxyindole-oxygen- methyltransferase (HIOMT), androgen receptor (AR), and estrogen receptor α (ERα) mRNA expression was significantly upregulated in the testis and epididymis of Tibetan sheep during the breeding season, whereas no clear upregulation of these genes was observed in the tissues of Small Tail Han sheep. MTNR1A and MTNR1B are important regulators of the HPTA in sheep. MTNR1A mediates seasonal estrus regulation in Tibetan sheep. Both MTNR1A and MTNR1B may play important roles in formation of the blood-epididymal barrier. The results of this study should help advance research on the mechanism of reproductive regulation of the HPTA in male animals and provide reference data for improving the reproductive rate of seasonal breeding animals.

Nanozyme-Activated Synergistic Amplification for Ultrasensitive Photoelectrochemical Immunoassay.

At present, enzyme-mediated signal amplification strategies have been widely applied in photoelectrochemical (PEC) biosensing systems, while the introduction of natural enzymes onto the surface of photoelectrodes inevitably obstructs the electron transfer due to their insulating properties as proteins, leading to severe damage to photocurrent. In this work, the PdPt bimetallic nanozymes with the efficient peroxidase-like activity were used as alternatives to natural enzymes and amplified PEC biosensing signals via their efficient enzymatic reaction and remarkable enhancement in photocurrent. As a result, photoactive CdS nanorods modified with PdPt bimetallic nanozymes showed a boosted PEC performance compared with the pristine CdS nanorods due to the localized surface plasmon resonance effect and Schottky junction. On the basis of the as-prepared CdS/PdPt photoelectrode, a sensitive split-type glucose oxidase-mediated PEC immunoassay for carcinoembryonic antigen (CEA) detection was successfully constructed. Along with the sandwich immunocomplexing, the subsequently produced hydrogen peroxide (H2O2) can oxidize 4-chloro-1-naphthol into insoluble precipitates to inhibit photocurrent and simultaneously trigger the bio-etching of CdS to further restrain photocurrent signals due to the excellent peroxidase-mimicking activity of PdPt nanozymes. Owing to the synergistic signal amplification fulfilled by PdPt nanozymes, an ultrasensitive immunoassay of CEA was realized with a wider linear range from 1 to 5000 pg/mL and a low detection limit of 0.21 pg/mL, opening a new avenue for building ultrasensitive PEC biosensors with nanozymes.

Single-Atom-Based Heterojunction Coupling with Ion-Exchange Reaction for Sensitive Photoelectrochemical Immunoassay.

Benefiting from the maximum atom-utilization efficiency and distinct structural features, single-atom catalysts open a new avenue for the design of more functional catalysts, whereas their bioapplications are still in their infancy. Due to the advantages, platinum single atoms supported by cadmium sulfide nanorods (Pt SAs-CdS) are synthesized to build an ultrasensitive photoelectrochemical (PEC) biosensing platform. With the decoration of Pt SAs, the PEC signal of CdS is significantly boosted. Furthermore, theory calculations indicate the positively charged Pt SAs could change the charge distribution and increase the excited carrier density of CdS. Meanwhile, it also suggests that Cu2+ can severely hinder the photoexcitation and electron-hole separation of CdS. As a proof of concept, prostate-specific antigen is chosen as the target analyte to demonstrate the superiority of the Pt SAs-CdS-based PEC sensing system. As a result, the PEC biosensor based on Pt SAs-CdS exhibits outstanding detection sensitivity and promising applicability.

Dissociable photoelectrode materials boost ultrasensitive photoelectrochemical detection of organophosphorus pesticides.

Generally, the photoactive materials are always tightly fixed on the photoelectrode of photoelectrochemical (PEC) sensors to produce excellent photocurrent response, while obvious and constant background currents will appear as well and then hamper the ultrasensitive sensing of target molecules. In this work, ultrasensitive detection of organophosphorus pesticides (OPs) is successfully fulfilled by using dissociable photoelectrode based on CdS nanocrystal-functionalized MnO2 nanosheets. With the assistance of acetylcholinesterase (AChE), acetylthiocholine (ATCh) is hydrolyzed into thiocholine (TCh) which can effectively etch the ultrathin MnO2 nanosheets, resulting in the dissociation of MnO2-CdS from the photoelectrode. Benefiting from the dissociation of photoactive materials, the background photocurrent induced by semiconductor itself dramatically decreases. OPs, as a specific inhibitor for AChE activity, can prevent the generation of TCh and the dissociation of MnO2 nanosheets, building a relationship between OPs concentration and photocurrent. Under the optimized test conditions, the PEC sensor for the detection of paraoxon displays a wide linear range from 0.05 to 10 ng/mL with a detection limit of 0.017 ng/mL. Furthermore, the PEC sensor shows good sensitivity, stability, and promising application in practical samples.

Germacrone protects against oxygen-glucose deprivation/reperfusion injury by inhibiting autophagy processes in PC12 cells.

BACKGROUND: Germacrone is an anti-inflammatory ingredient in the Chinese medicine zedoary turmeric. The purpose of this study was to explore the protective mechanism of germacrone against PC12 cells injury caused by oxygen-glucose deprivation/reperfusion (OGD/R). METHODS: OGD/R injury model of PC12 cells was established by using OGD/R (2 h/24 h). The cell viability was assessed by MTT assay and LDH release. The ultrastructure of cells was observed by transmission electron microscopy (TEM). The expression of autophagy related proteins in cells was determined by Western Blot. RESULTS: The results of ultrastructural observation showed that PC12 cells damaged by OGD/R showed typical autophagy characteristics. In addition, OGD/R observably up-regulated the expression of autophagy related proteins: the class III type phosphoinositide 3-kinase (PI3K III), light chain 3(LC3), and Beclin-1 in PC12 cells, and inhibited the expression of the class I type phosphoinositide 3-kinase (PI3K I), Protein kinase B (Akt), the mammalian target of rapamycin (mTOR), and B-cell lymphoma 2(Bcl-2) proteins. Furthermore, germacrone increased the cell viability of OGD/R-damaged PC12 cells by down-regulating the expression of LC3 protein in cells in a concentration-dependent manner. More importantly, germacrone significantly inhibited the expression of PI3K III, LC3, and Beclin-1 in OGD/R-injured PC12 cells, and up-regulated the expressionof PI3K I, Akt, mTOR, and Bcl-2 proteins in cells, and this inhibited or up-regulated effect was reversed by PI3K I inhibitor (ZSTK474). CONCLUSION: The above results indicated that germacrone could inhibit the autophagy effect in OGD/R injury model of PC12 cells, the mechanism of inhibition was regulated by PI3K III/Beclin-1/Bcl-2 and PI3K I/Akt/mTOR pathways, thereby improving the cell viability of PC12 cells and playing a neuroprotective role, which provided a new drug for the treatment of OGD/R.