Clinicopathological characteristics of gastric cancer patients with dermatomyositis and analysis of perioperative management: a case series study.

Background: This study aimed to investigate the clinical characteristics of gastric cancer (GC) patients with dermatomyositis (DM) and summarize the perioperative outcomes. Methods: The clinical and pathological data of five patients diagnosed with co-occurring DM and GC (DM-GC group) were retrospectively analyzed, who were admitted to the Department of Gastrointestinal Surgery at Ren ji Hospital, Shanghai Jiao Tong University, between January 2012 and April 2023. Their data were compared with 618 GC patients (GC-1 group) from September 2016 to August 2017 and 35 GC patients who were meticulously screened from 14,580 GC cases from January 2012 and April 2023. The matching criteria included identical gender, age, tumor location, TNM stage, and surgical procedure (7 GC patients were matched for each DM-GC patient). Results: Analysis indicated that the DM-GC group comprised four female and one male patient. The female proportion was significantly higher (P = 0.032) than that of GC-1 group. In DM-GC group, four DM patients were diagnosed as GC within 12 months. One DM patients was diagnosed as GC within 15 months. Among them, four patients presented with varying degrees of skin rashes, muscle weakness while one patient had elevated CK levels as the typical symptom. Similarly, the preoperative tumor markers (CA-199 and CA-125) in the DM-GC group were significantly higher than normal levels (CA-199: 100 vs. 28.6%, P = 0.002; CA-125: 40 vs. 2.9%, P = 0.003) compared to GC-2 group. Moreover, postoperative complication incidence and the length of hospital stay were significantly higher in the DM-GC than GC-2 group [complication rate: 40 vs. 8.6%, P = 0.047; hospital stay: 15 days (range: 9-28) vs. 9 days (range: 8-10), P = 0.021]. Conclusion: GC Patients with dermatomyositis are more prone to experience postoperative complications and longer hospital stay.

A novel pyrene-based fluorescent probe for Al3+ detection.

Based on the classical Schiff base reaction, fluorescent probe dimethyl 5-((pyren-1-ylmethylene)amino)isophthalate (PAI) is designed and synthesized through introducing Schiff base structure to pyrene unit for structural modification. The structure of the synthesized probe PAI is determined and characterized by FT-IR, 1H NMR, 13C NMR and HRMS. PAI is a type of "turn-on" probe which can specifically recognize Al3+ ion with high selectivity. The limit of detection is calculated to be 3.07 × 10-8 M, which proves the probe's high sensitivity and is lower than that of many efficient reported probes. The probe PAI is intrinsically non-fluorescent due to the photoinduced electron transfer (PET) process. However, the addition of Al3+ ion leads to the breakage of the carbon-nitrogen double bond of Schiff base in PAI resulting in the product without PET property, which shows a typical localized state with enhanced fluorescence and blue color. In addition, PAI can recognize Al3+ ion through test papers, which is in favor of the future research regarding to Al3+ ion sensing.

Stabilization of Multimeric Proteins via Intersubunit Cyclization.

Proteins with high catalytic efficiency and selectivity under mild conditions have long been appreciated by industrial and medicinal fields. These proteins, which are commonly multimeric, often possess low stability, impeding wider application. Currently, strategies to improve the stability of multimeric proteins concentrate on enhancing the interaction at internal interface of the subunits. In this report, we confirmed that the largely underestimated subunit terminal ends are as significant as the internal interface for protein stability. By connecting both the terminal ends and internal interface of subunits, the tetrameric Leifsonia alcohol dehydrogenase (LnADH) protein can been cyclized into a rigid form with significantly improved thermostability and resilience. The improvement in the temperature at which enzyme activity is reduced to 50% after a 15-min heat treatment (T5015) and melting temperature (Tm ) of the modified protein was 18°C and 23.3°C, respectively, which is superior to the results achieved by normal protein engineering. Our study provided a novel strategy to effectively improve the stability of multimeric proteins, which is suitable not only for the short-chain dehydrogenase/reductase (SDR) family but also other classes of proteins with close terminal ends.IMPORTANCE Industrially interesting proteins are generally multimeric proteins; however, their applications are often restricted due to low stability caused by the natural tendency of subunit disassociation. Current approaches targeting this problem mainly focus on enhancing the internal interfaces of the subunits to avoid their disassociation. In this study, we identified and confirmed the external interface to be significant for improving the stability of multimeric proteins. By connecting the terminal ends and internal interface with disulfide bonds, we found that the multimeric protein LnADH cyclized into a robust monomeric-like form, resulting in superior thermostability compared to traditional protein engineering. This intersubunit cyclization approach is efficient and easy to perform, providing a novel method for engineering many important classes of multimeric proteins.

Enhancing the biocatalytic manufacture of the key intermediate of atorvastatin by focused directed evolution of halohydrin dehalogenase.

Halohydrin dehalogenases (HHDHs) are biocatalytically interesting enzymes due to their ability to form C-C, C-N, C-O, and C-S bonds. One of most important application of HHDH was the protein engineering of HheC (halohydrin dehalogenase from Agrobacterium radiobacter AD1) for the industrial manufacturing of ethyl (R)-4-cyano-3-hydroxybutanoate (HN), a key chiral synthon of a cholesterol-lowering drug of atorvastatin. During our development of an alternative, more efficient and economic route for chemo-enzymatic preparation of the intermediate of atorvastatin, we found that the HheC2360 previously reported for HN manufacture, had insufficient activity for the cyanolysis production of tert-butyl (3 R,5 S)-6-cyano-3,5-dihydroxyhexanoate (A7). Herein, we present the focused directed evolution of HheC2360 with higher activity and enhanced biocatalytic performance using active site mutagenesis. Through docking of the product, A7, into the crystal structure of HheC2360, 6 residues was selected for combined active sites testing (CASTing). After library screening, the variant V84G/W86F was identified to have a 15- fold increase in activity. Time course analysis of the cyanolysis reaction catalyzed by this variant, showed 2- fold increase in space time productivity compared with HheC2360. These results demonstrate the applicability of the variant V84G/W86F as a biocatalyst for the efficient and practical production of atorvastatin intermediate.