The impact of postmastectomy radiotherapy on cT1-2N1 breast cancer patients with ypN0 after neoadjuvant chemotherapy: a retrospective study based on real-world data.

BACKGROUND: The role of postmastectomy radiation therapy (PMRT) in clinical T1-2N1 breast cancer patients who achieve axillary pathological complete response (ypN0) after neoadjuvant chemotherapy (NAC) is controversial. METHODS: Data from cT1-2N1 breast cancer patients who converted to ypN0 after NAC and subsequent surgery were retrospectively analyzed. Disease-free survival (DFS) and overall survival (OS) were estimated using the Kaplan‒Meier method. Univariate and multivariate Cox regression models were applied to investigate the correlations between clinical or pathological parameters and survival. RESULTS: From 2012-2019, we identified 116 cases for analysis, including 31 (26.7%) who received PMRT and 85 (73.3%) who did not. At a median follow-up time of 56.4 months, the 5-year DFS and OS rates were 90.2% and 96.7% with PMRT and 93.7% and 97.3% without PMRT, respectively. PMRT did not affect either DFS (p = 0.234) or OS (p = 0.878). On multivariate analyses, no differences in DFS or OS between the two groups were detected, taking into consideration the following factors: age, molecular subtype, Ki67 index, cT stage, and in-breast pathologic complete response (DFS: HR 2.260; 95% CI 0.465-10.982; p = 0.312. OS: HR 1.400; 95% CI 0.138-14.202; p = 0.776). This nonsignificant difference was also consistent in subgroup analyses (all p > 0.05). CONCLUSIONS: PMRT has limited ability to confer DFS or OS benefits for cT1-2N1 breast cancer patients who achieved axillary pathological complete response after NAC and total mastectomy. It is imperative to conduct prospective studies to investigate the safety and feasibility of omitting PMRT. TRIAL REGISTRATION: This research was approved by the Ethics Committee of The First Affiliated Hospital of Chongqing Medical University (ID: No. 2021-442).

Investigating Patients' Continuance Intention Toward Conversational Agents in Outpatient Departments: Cross-sectional Field Survey.

BACKGROUND: Conversational agents (CAs) have been developed in outpatient departments to improve physician-patient communication efficiency. As end users, patients' continuance intention is essential for the sustainable development of CAs. OBJECTIVE: The aim of this study was to facilitate the successful usage of CAs by identifying key factors influencing patients' continuance intention and proposing corresponding managerial implications. METHODS: This study proposed an extended expectation-confirmation model and empirically tested the model via a cross-sectional field survey. The questionnaire included demographic characteristics, multiple-item scales, and an optional open-ended question on patients' specific expectations for CAs. Partial least squares structural equation modeling was applied to assess the model and hypotheses. The qualitative data were analyzed via thematic analysis. RESULTS: A total of 172 completed questionaries were received, with a 100% (172/172) response rate. The proposed model explained 75.5% of the variance in continuance intention. Both satisfaction (ß=.68; P<.001) and perceived usefulness (ß=.221; P=.004) were significant predictors of continuance intention. Patients' extent of confirmation significantly and positively affected both perceived usefulness (ß=.817; P<.001) and satisfaction (ß=.61; P<.001). Contrary to expectations, perceived ease of use had no significant impact on perceived usefulness (ß=.048; P=.37), satisfaction (ß=-.004; P=.63), and continuance intention (ß=.026; P=.91). The following three themes were extracted from the 74 answers to the open-ended question: personalized interaction, effective utilization, and clear illustrations. CONCLUSIONS: This study identified key factors influencing patients' continuance intention toward CAs. Satisfaction and perceived usefulness were significant predictors of continuance intention (P<.001 and P<.004, respectively) and were significantly affected by patients' extent of confirmation (P<.001 and P<.001, respectively). Developing a better understanding of patients' continuance intention can help administrators figure out how to facilitate the effective implementation of CAs. Efforts should be made toward improving the aspects that patients reasonably expect CAs to have, which include personalized interactions, effective utilization, and clear illustrations.

Integrative transcriptomics and metabolomics analyses provide hepatotoxicity mechanisms of asarum.

Asarum is frequently applied in combination with other agents for prescriptions in practices of Traditional Chinese Medicine. A number of studies have previously indicated that asarum treatment induces lung toxicity by triggering inflammation. However, the potential effects of asarum in the liver and the underlying mechanisms have remained largely elusive. Therefore, transcriptomics and metabolomics approaches were used in the present study to examine the mechanisms of the hepatotoxicity of asarum. Specifically, mRNA and metabolites were obtained from rat liver samples following intragastric administration of asarum powder. RNA sequencing analysis was subsequently performed to screen for differentially expressed genes (DEGs), and a total of 434 DEGs were identified in liver tissue samples, 214 of which were upregulated and 220 were downregulated. Pathway enrichment analysis found that these genes were particularly enriched in processes including the regulation of p53 signaling, metabolic pathways and bile secretion. To investigate potential changes to the metabolic profile as a result of asarum treatment, a metabolomics analysis was performed, which detected 14 significantly altered metabolites in rat liver samples by gas chromatography-mass spectrometry. These metabolites were predominantly members of the taurine, hypotaurine and amino acid metabolic pathways. Metscape network analyses were subsequently performed to integrate the transcriptomics and metabolomics data. Integrative analyis revealed that the DEGs and metabolites were primarily associated with bile acid biosynthesis, amino acid metabolism and the p53 signaling pathway. Taken together, these results provide novel insight into the mechanism of asarum-mediated hepatotoxicity, which may potentially aid the clinical diagnosis and future therapeutic intervention of asarum poisoning.

[Analysis of 2, 3-pyridinedicarboximide and its products conversed by engineering strain with high performance liquid chromatography].

A high performance liquid chromatography (HPLC) method was established for the detection of 2, 3-pyridinedicarboximide (PDI) and its enzyme reaction products, 3-carbamoyl-α-picolinic acid (α-3CP), using an engineering strain containing the D-hydantoinase gene expression box.The strain pET3a-hyd/BL21(DE3) was collected after induction and added to a PDI saturated aqueous solution.After reacting at 37℃ for 30 min with constant stirring, the supernatant was separated by centrifugation at 13000 r/min and detected by HPLC.The chromatographic conditions were as follows:HypersilTM GOLD C18 column (250 mm×4.6 mm, 5 µm), H2O-acetonitrile (90:10, v/v) containing 0.1%(v/v) trifluoroacetic acid as the mobile phase with a flow rate of 1 mL/min and a detection wavelength of 254 nm.The specific activity of pET3a-hyd/BL21(DE3) was found to be 0.61 U/(mL·10OD600 nm).This study provides a theoretical basis for the preparation of complicated half-amides using biological methods.

Ratiometric fluorescence monitoring of cerebral Cu2+ based on coumarin-labeled DNA coupled with the Cu2+-induced oxidation of o-phenylenediamine.

A novel and facile ratiometric fluorescence method for evaluating Cu2+ has been developed based on coumarin-labeled single-stranded DNA (C-ssDNA) coupled with the Cu2+-induced oxidation of o-phenylenediamine (OPD). By combining the microdialysis technique, the ratiometric fluorescence method has also been successfully exploited to monitor the cerebral Cu2+ in the rat brain, promising new opportunities for studying the cerebral Cu2+-associated physiological and pathological events.

Selective and Sensitive Monitoring of Cerebral Antioxidants Based on the Dye-Labeled DNA/Polydopamine Conjugates.

A simple and novel method for evaluating antioxidants in complex biological fluids has been developed based on the interaction of dye-labeled single-strand DNA (ssDNA) and polydopamine (PDA). Due to the interaction between ssDNA and PDA, the fluorescence of dye-labeled ssDNA (e.g., FITC-ssDNA, as donor) can be quenched by PDA (as acceptor) to the fluorescence "off" state through Förster resonance energy transfer (FRET). However, in the presence of various antioxidants, such as glutathione (GSH), ascorbic acid (AA), cysteine (Cys), and homocysteine (Hcys), the spontaneous oxidative polymerization reaction from DA to PDA would be blocked, resulting in the freedom of FITC-ssDNA and leading to the fluorescence "on" state. The sensing system shows great sensitivity for the monitoring of antioxidants in a fluorescent "turn on" format. The new strategy also exhibits great selectivity and is free from the interferences of amino acids, metal ions and the biological species commonly existing in brain systems. Moreover, by combining the microdialysis technique, the present method has been successfully applied to monitor the dynamic changes of the striatum antioxidants in rat cerebrospinal microdialysates during the normal/ischemia/reperfusion process. This work establishes an effective platform for in vivo monitoring antioxidants in cerebral ischemia model, and promises new opportunities for the research of brain chemistry, neuroprotection, physiological, and pathological events.

Using graphene-based plasmonic nanocomposites to quench energy from quantum dots for signal-on photoelectrochemical aptasensing.

On the basis of the absorption and emission spectra overlap, an enhanced resonance energy transfer caused by excition-plasmon resonance between reduced graphene oxide (RGO)-Au nanoparticles (AuNPs) and CdTe quantum dots (QDs) was obtained. With the synergy of AuNPs and RGO as a planelike energy acceptor, it resulted in the enhancement of energy transfer between excited CdTe QDs and RGO-AuNPs nanocomposites. Upon the novel sandwichlike structure formed via DNA hybridization, the exciton produced in CdTe QDs was annihilated. A damped photocurrent was obtained, which was acted as the background signal for the development of a universal photoelectrochemical (PEC) platform. With the use of carcinoembryonic antigen (CEA) as a model which bonded to its specific aptamer and destroyed the sandwichlike structure, the energy transfer efficiency was lowered, leading to PEC response augment. Thus a signal-on PEC aptasensor was constructed. Under 470 nm irradiation at -0.05 V, the PEC aptasensor for CEA determination exhibited a linear range from 0.001 to 2.0 ng mL(-1) with a detection limit of 0.47 pg mL(-1) at a signal-to-noise ratio of 3 and was satisfactory for clinical sample detection. Since different aptamers can specifically bind to different target molecules, the designed strategy has an expansive application for the construction of versatile PEC platforms.