Conventional versus rubber band traction-assisted endoscopic submucosal dissection for rectal neuroendocrine tumors: a single-center retrospective study (with video).

BACKGROUND: Endoscopic submucosal dissection (ESD) is a safe and effective technique for the treatment of gastrointestinal tumors, including rectal neuroendocrine tumors (r-NETs). However, the relative advantages of traction-assisted ESD for the treatment of small rectal lesions are still debated. AIMS: We conducted a study to compare the efficacy and safety of rubber band traction-assisted ESD (RBT-ESD) to conventional ESD (C-ESD). METHODS: This study retrospectively analyzed consecutive patients with r-NET treated with ESD between October 2021 and October 2023. Our study assessed differences between the groups in the complete resection rate of lesions, muscular layer injury, surgical complications, operation time, resection speed, time to liquid diet, postoperative hospital stay, hospital cost, and recurrence rate. RESULTS: A total of 119 patients with r-NETs participated in this study (RBT-ESD group, n = 27; C-ESD group, n = 92). The operation time in RBT-ESD group was shorter than in C-ESD group, but the difference was not statistically significant (16.0 min [9.0-22.0 min] vs. 18.0 min [13.3-27.0 min], P = 0.056). However, the resection speed was significantly faster in the RBT-ESD group (6.7 vs. 4.1 mm2/min, P = 0.005). Furthermore, the RBT-ESD group showed significantly less muscular layer injury (P = 0.047) and faster diet recovery (P = 0.035). No significant differences were observed in the complete resection rate, surgical complications, postoperative hospital stay, hospital cost, or recurrence rate between the two groups. CONCLUSION: For r-NETs of < 2 cm in size, the RBT method did not significantly shorten the operation time but resulted in faster resection speed, less muscular layer injury, and earlier postoperative recovery to a liquid diet.

Two Sesterterpene Synthases from Lentzea atacamensis Demonstrate the Role of Conformational Variability in Terpene Biosynthesis.

Mining of two multiproduct sesterterpene synthases from Lentzea atacamensis resulted in the identification of the synthases for lentzeadiene (LaLDS) and atacamatriene (LaATS). The main product of LaLDS (lentzeadiene) is a new compound, while one of the side products (lentzeatetraene) is the enantiomer of brassitetraene B and the other side product (sestermobaraene F) is known from a surprisingly distantly related sesterterpene synthase. LaATS produces six new compounds, one of which is the enantiomer of the known sesterterpene Bm1. Notably, for both enzymes the products cannot all be explained from one and the same starting conformation of geranylfarnesyl diphosphate, demonstrating the requirement of conformational flexibility of the substrate in the enzymes' active sites. For lentzeadiene an intriguing thermal [1,5]-sigmatropic rearrangement was discovered, reminiscent of the biosynthesis of vitamin D3. All enzyme reactions and the [1,5]-sigmatropic rearrangement were investigated through isotopic labeling experiments and DFT calculations. The results also emphasize the importance of conformational changes during terpene cyclizations.

Association of KMT2C/D loss-of-function variants with response to immune checkpoint blockades in colorectal cancer.

Immune checkpoint inhibitors (ICIs) have become important treatment strategies, yet responses vary among patients and predictive biomarkers are urgently needed. Mutations in KMT2C and KMT2D lead to increased levels of genomic instability. Therefore, we aimed to examine whether KMT2C/D mutations might be a predictor of immunotherapeutic efficacy. Here, we investigated the associations of KMT2C/D loss-of-function (LOF) variants with tumor mutation burden (TMB), MSI-H, PD-L1 expression, the levels of tumor-infiltrating leukocytes (TILs), and clinical response to ICIs. It was found that KMT2C/D LOF variants were associated with higher TMB. Compared with the non-LOF group, the proportion of patients with MSI-H tumors was larger in the LOF group. PD-L1 expression was higher in the LOF group only for colorectal cancer in both the Chinese and The Cancer Genome Atlas cohorts. Importantly, KMT2C/D LOF variants were associated with decreased regulatory T cells and increased levels of CD8+ T cells, activated NK cells, M1 macrophages, and M2 macrophages in colorectal cancer. However, there was no significant association between KMT2C/D LOF and TILs levels in other cancer types. Consistently, the results showed that KMT2C/D LOF variants were associated with prolonged overall survival only in colorectal cancer (p = 0.0485). We also presented that patients with KMT2C/D LOF mutations exhibited a better clinical response to anti-PD-1 therapy in a Chinese colorectal cancer cohort (p = 0.002). Taken together, these results suggested that KMT2C/D LOF variants could be a useful predictor for ICIs efficacy in colorectal cancer. In addition, the predictive value of KMT2C/D LOF variants was consistent with their association with TILs levels.

Functional Characterisation of Highly Conserved and Structurally Prominent Residues of 2-Methylisoborneol Synthase.

2-Methylisoborneol is a widespread musty odourant that is produced by many bacteria including actinomycetes, cyanobacteria and myxobacteria. Two 2-methylisoborneol synthases (MIBS) that are phylogenetically distant to the known enzyme from Streptomyces coelicolor were found to be highly active for 2-methylisoborneol biosynthesis. Based on the enzyme structure and on an amino acid sequence alignment, the MIBS from S. coelicolor was extensively studied through site-directed mutagenesis.

ARL9 is upregulated and serves as a biomarker for a poor prognosis in colon adenocarcinoma.

BACKGROUND: ARL9 is a newly identified member of the ARF family, and the clinical significance of ARL9 in colon adenocarcinoma is unknown. In this study, we aimed to explore the expression of ARL9 mRNA in colon adenocarcinoma, and its effect on the prognosis of patients with colon adenocarcinoma. METHODS: We investigated the differential expression of ARL9 between colon adenocarcinoma tissue and adjacent tissues through a bioinformatics analysis using The Cancer Genome Atlas (TCGA) database. The correlation between clinical characteristics and the mRNA expression level of ARL9 were analyzed. A survival analysis and a Cox regression analysis were used to determine the prognostic significance of ARL9. Finally, we conducted a gene set enrichment analysis (GSEA) to explore the ARL9 signaling pathways involved in the development of colon adenocarcinoma. The effect of the expression of ARL9 on the proliferation and migration of colon adenocarcinoma was analyzed by the CCK8 method and a cell scratch test, respectively. RESULTS: The mRNA expression of ARL9 in colon adenocarcinoma tissues was higher in comparison to the level in normal adjacent tissues (P < 0.05). The mRNA expression of ARL9 was not related to sex, tumor stage, T stage, N stage, M stage, but to age. The 5-year survival rate of colon adenocarcinoma patients with high ARL9 mRNA expression levels was significantly lower than that of patients with low ARL9 mRNA expression levels (P < 0.05). Age and the high mRNA expression of ARL9 were independent risk factors for a poor prognosis in patients with colon adenocarcinoma. The GSEA suggested that ARL9 may be able to upregulate cell adhesion, extracellular matrix receptor interactions, tumor-associated pathways, and downregulate the citrate cycle and tricarboxylic acid cycle pathway, which are involved in the development of colon adenocarcinoma. After knocking down ARL9, the proliferation and migration abilities of colon adenocarcinoma cells were decreased (P < 0.01). CONCLUSION: The mRNA expression of ARL9 is upregulated in colon adenocarcinoma, and higher mRNA expression levels are associated with a poor prognosis. Knocking down ARL9 can reduce the proliferation and migration of colon adenocarcinoma cells. ARL9 mRNA can be used as a prognostic biomarker in patients with colon adenocarcinoma.

Persistent Helicobacter pylori infection leads to elevated fasting plasma glucose level: A retrospective cohort study based on a nondiabetes Chinese population.

BACKGROUND AND AIM: The relationship between Helicobacter pylori (H. pylori) and fast plasma glucose (FPG) on nondiabetes populations is still inconclusive. Nowadays, not only the high infection rate of H. pylori but also the high FPG level is threatening the Chinese people. METHODS: A retrospective cohort study has been established to analyze the relationship between H. pylori infection and FPG level, 18 164 individuals performed healthy examination in Taizhou Hospital Health Examination Center from 2017 to 2022 were included, and hematological indicators, body parameters, and H. pylori detection by 13 C-urea breath test were collected from patients. The follow-up intervals were greater than 12 months. RESULTS: H. pylori infection was regarded as an independent risk factor for elevated FPG after multivariate logistic regression. Additionally, the average interval time were 33.6 ± 13.3 months. Mean changed FPG values in the persistent infection group were higher than in the subgroup of persistent negative (P = 0.029) as well as eradication infection (P = 0.007). The aforementioned changes began to appear after 2 years of follow-up. Similarly, when compared with the subgroup of persistent infection, mean changed triglyceride/high density lipoprotein (TG/HDL) values were much lower in the subgroup of persistent negative (P = 0.008) and eradication infection (P = 0.018), but the differences appeared after 3 years of follow-up. CONCLUSIONS: H. pylori infection is an independent risk factor for elevated FPG in non-diabetes mellitus (DM) individuals. Persistent H. pylori infection causes an increase in FPG level and TG/HDL, which may be a risk factor for diabetes mellitus.

Ruptenes: A Family of Terpene Analogs Give Insight into Cyclisation Mechanisms by Cascade Disruption.

The terpenoid substrate analogs (7R)-6,7-dihydrogeranylgeranyl diphosphate (6,7-dihydro-GGPP) and (7R)-6,7-dihydrogeranylfarnesyl diphosphate (6,7-dihydro-GFPP) were synthesised from (S)-citronellol and enzymatically converted with nine diterpene and two sesterterpene synthases, respectively. In two cases the substrate analogs were converted into diterpenes in cyclisation reactions corresponding to those observed for the native substrate GGPP, while the cyclisation cascade was disrupted or redirected in the other nine cases, leading to products that were named ruptenes. Several of the isolated ruptenes represent deprotonation products of cationic intermediates that are analogs of the intermediates proposed along the cyclisation cascades for the native substrates GGPP or GFPP, thus giving insights into the complex reaction mechanisms of terpene synthase mediated biosynthesis.

Mechanistic Characterisation and Engineering of Sesterviolene Synthase from Streptomyces violens.

The sesterviolene synthase from Streptomyces violens was identified and represents the second known sesterterpene synthase from bacteria. Isotopic labelling experiments in conjunction with DFT calculations were performed that provided detailed insight into its complex cyclisation mechanism. Enzyme engineering through site-directed mutagenesis gave access to a high-yielding enzyme variant that provided six additional minor products and the main product in sufficient quantities to study its chemistry.

Subrutilane-A Hexacyclic Sesterterpene from Streptomyces subrutilus.

Mining of a terpene synthase from Streptomyces subrutilus resulted in the identification of the hexacyclic sesterterpene subrutilane, besides eight pentacyclic side products. Subrutilane represents the first case of a saturated sesterterpene hydrocarbon. Its structure, including the absolute configuration, was unambiguously determined through X-ray crystallographic analysis and stereoselective deuteration. The cyclisation mechanism to subrutilane and its side products was investigated in all detail by isotopic labelling experiments and DFT calculations. The subrutilane synthase (SrS) also converted (2Z)-GFPP into one major product. Additional compounds were obtained from the substrate analogues (7R)-6,7-dihydro-GFPP and (2Z,7R)-6,7-dihydro-GFPP with blocked reactivity at the C6-C7 bond. Interestingly, the early steps of the cyclisation cascade with (2Z)-GFPP and the saturated substrate analogues were analogous to those of GFPP, but then deviations from the natural cyclisation mode occur.

Functions of enzyme domains in 2-methylisoborneol biosynthesis and enzymatic synthesis of non-natural analogs.

Two aspects of the biosynthesis of the non-canonical terpene synthase for 2-methylisoborneol have been studied. Several 2-methylisoborneol synthases have a proline-rich N-terminal domain of unknown function. The results presented here demonstrate that this domain leads to a reduced enzyme activity, in addition to its ability to increase long-term solubility of the protein. Furthermore, the substrate scope of the 2-methylisoborneol synthase was investigated through enzyme incubations with several substrate analogs, giving access to two C12 monoterpenoids. Implications on the stereochemical course of the terpene cyclisation by 2-methylisoborneol synthase are discussed.

Functional characterisation of twelve terpene synthases from actinobacteria.

Fifteen type I terpene synthase homologs from diverse actinobacteria that were selected based on a phylogenetic analysis of more than 4000 amino acid sequences were investigated for their products. For four enzymes with functions not previously reported from bacterial terpene synthases the products were isolated and their structures were elucidated by NMR spectroscopy, resulting in the discovery of the first terpene synthases for (+)-δ-cadinol and (+)-α-cadinene, besides the first two bacterial (-)-amorpha-4,11-diene synthases. For other terpene synthases with functions reported from bacteria before the products were identified by GC-MS. The characterised enzymes include a new epi-isozizaene synthase with monoterpene synthase side activity, a 7-epi-α-eudesmol synthase that also produces hedycaryol and germacrene A, and four more sesquiterpene synthases that produce mixtures of hedycaryol and germacrene A. Three phylogenetically related enzymes were in one case not expressed and in two cases inactive, suggesting pseudogenisation in the respective branch of the phylogenetic tree. Furthermore, a diterpene synthase for allokutznerene and a sesterterpene synthase for sesterviolene were identified.

High Versatility of IPP and DMAPP Methyltransferases Enables Synthesis of C6 , C7 and C8 Terpenoid Building Blocks.

The natural substance class of terpenoids covers an extremely wide range of different structures, although their building block repertoire is limited to the C5 compounds DMAPP and IPP. This study aims at the characterization of methyltransferases (MTases) that modify these terpene precursors and the demonstration of their suitability for biotechnological purposes. All seven enzymes tested accepted IPP as substrate and altogether five C6 compounds and six C7 compounds were formed within the reactions. A high selectivity for the deprotonation site as well as high stereoselectivity could be observed for most of the biocatalysts. Only the enzyme from Micromonospora humi also accepted DMAPP as substrate, converting it into (2R)-2-methyl-IPP in vitro. In vivo studies demonstrated the production of a C8 compound and a hydride shift step within the MTase-catalyzed reaction. Our study presents IPP/DMAPP MTases with very different catalytic properties, which provide biosynthetic access to many novel terpene-derived structures.

Distribution and clinical significance of circulating CD8+CD28- regulatory T cells in the peripheral blood of patients with pulmonary tuberculosis.

BACKGROUND: Regulatory T cells (Treg cells) in the peripheral blood of patients with pulmonary tuberculosis (PTB) may be closely related to the progression of PTB. In this study, the distribution characteristics and clinical importance of CD8+CD28- Treg cells in patients with tuberculosis were systematically analyzed, and the role and importance of CD8+CD28- Treg cells in influencing the immune response and progression of tuberculosis were discussed, which will provide immunological indices and reference values for the clinical diagnosis of tuberculosis. METHODS: Flow cytometry, sputum smears and computed tomography imaging were used to analyze the distribution characteristics of CD8+CD28- Treg cells in the peripheral blood of patients with PTB and the correlation between CD8+CD28-Treg cells and clinical and immune indices. RESULTS: The percentages of CD4+CD25high and CD8+CD28- Treg cells in the peripheral blood of patients with PTB were significantly higher than those in the healthy control (HC) group. Further analysis showed that the percentage of CD4+CD25highTreg cells in the Stage II group was significantly higher than that in the HC group. The percentages of CD4+CD25high and CD8+CD28- Treg cells increased significantly in patients in the Stage II group. The proportion of CD8+CD28- Treg cells was directly proportional to the degree of positivity in sputum smears, while CD4+CD25highTreg cells did not exhibit this trend. The correlations between the percentage of CD4+CD25high and CD8+CD28- Treg cells and the percentage of lymphocyte subsets were examined. The percentage of CD8+CD28- Treg cells was negatively correlated with the percentage of CD4+T cells and positively correlated with the CD8+T cell percentage in the HC and PTB groups. The percentage of CD4 + CD25highTreg cells was positively correlated with the percentage of CD4+T cells only in the PTB group. CONCLUSIONS: This study was the first to show that the proportion of CD8+CD28- Treg cells in the peripheral blood of patients with PTB was significantly increased, and the increase in CD8+CD28- Treg cells was related to the progression of PTB, which may affect the proportion of immune cell subsets by inhibiting the immune response, resulting in the progression of PTB.

The stereochemical course of 2-methylisoborneol biosynthesis.

Both enantiomers of 2-methyllinalyl diphosphate (2-Me-LPP) were synthesized enantioselectively using Sharpless epoxidation as a key step and purification of enantiomerically enriched intermediates through HPLC separation on a chiral stationary phase. Their enzymatic conversion with 2-methylisoborneol synthase (2MIBS) demonstrates that (R)-2-Me-LPP is the on-pathway intermediate, while a minor formation of 2-methylisoborneol from (S)-2-Me-LPP may be explained by isomerization to 2-Me-GPP and then to (R)-2-Me-LPP.

Asperfloketals A and B, the First Two Ergostanes with Rearranged A and D Rings: From the Sponge-Associated Aspergillus flocculosus 16D-1.

Asperfloketals A (1) and B (2), two 1(10 → 6)-abeo-14,15-secosteroids featuring a novel trioxahexaheterocyclic ring system, were isolated from the sponge-associated fungus Aspergillus flocculosus 16D-1. Their structures were elucidated by extensive spectroscopic analysis and NMR chemical shifts calculations, supported by DP4+ probability analysis, and their absolute configurations were determined by ECD calculations and the modified Mosher's method. Asperfloketals A and B showed strong anti-inflammatory activity in the CuSO4-induced transgenic fluorescent zebrafish but displayed no cytotoxicity against HeLa, HepG2, and SW480 cell lines.

No intrauterine vertical transmission in pregnancy with COVID-19: A case report.

The coronavirus disease 2019 (COVID-19) has been a worldwide pandemic diseases, nearly 400,000 people died at now. The data of status of pregnant women and neonates after infection of severe acute respiratory syndrome coronavirus 2 (SARS-COV-2) is limited. We report a case of pregnant woman in her third trimester with critical COVID-19, and amniotic fluid, umbilical cord blood, placenta, and neonatal gastric fluid were retained during cesarean section. The SARS-COV-2 nucleic acid test results of these specimens were negative. There is no evidence of intrauterine vertical transmission during delivery in the third trimester, but the data are limited and need to be further explored.

Dactylospenes A-E, Sesterterpenes from the Marine Sponge Dactylospongia elegans.

Chemical investigation on a marine sponge, Dactylospongia elegans, yielded five new γ-oxygenated butenolide sesterterpene derivatives, dactylospenes A-E (1-5), as well as two known biosynthetically related compounds, luffariellolide (6) and furospinosulin B (7). The structures of these compounds were elucidated on the basis of their spectroscopic data, experimental and calculated electronic circular dichroism (ECD) analysis, as well as comparison of the NMR data with those of known analogs. These metabolites are the first γ-oxygenated butenolide sesterterpenes to be reported from this genus. These compounds were evaluated in antimicrobial, anti-inflammatory, and cytotoxic assays. Only compounds 1, 3, and 6 exhibited moderate cytotoxicity against DU145, SW1990, Huh7, and PANC-1 cancer cell lines with IC50 values in the range of 2.11-13.35 µM. Furthermore, compound 2, without cytotoxicity, exhibited significant inhibitory effects (inhibitory rate 77.5%) on nitric oxide production induced by lipopolysaccharide at 10 µM.

E2F1-mediated MNX1-AS1-miR-218-5p-SEC61A1 feedback loop contributes to the progression of colon adenocarcinoma.

The long noncoding RNA MNX1-AS1 has been reported to facilitate the progression of glioblastoma and ovarian cancer. Nevertheless, the biological roles and underlying mechanisms of MNX1-AS1 in colon adenocarcinoma have not been studied until now. In the current study, MNX1-AS1 was upregulated in colon adenocarcinoma. JASPAR prediction tool showed that E2F1 could bind to the promoter region of MNX1-AS1. The chromatin immunoprecipitation assay and luciferase reporter assay were used to verify the interactions between MNX1-AS1 and E2F1. Then functional assays revealed that downregulation of MNX1-AS1 decreased cell proliferation, migration, and invasion in colon adenocarcinoma, but upregulation of E2F1 reversed the effects. Moreover, subcellular fractionation assay manifested that MNX1-AS1 was enriched in the cytoplasm of colon adenocarcinoma cells, thus we speculated whether MNX1-AS1 could function as a competing endogenous RNA (ceRNA) to play roles in colon adenocarcinoma. Bioinformatics analysis and luciferase reporter assay indicated that MNX1-AS1 could sponge microRNA-218-5p (miR-218-5p). Furthermore, we discovered that SEC61A1 was downstream target of miR-218-5p, and MNX1-AS1 acted as a ceRNA to upregulate the expression of SEC61A1 through sponging miR-218-5p. Finally, rescue assays confirmed that MNX1-AS1 facilitated the progression of colon adenocarcinoma through regulating miR-218-5p/SEC61A1 axis. Taken together, we concluded that E2F1-mediated MNX1-AS1-miR-218-5p-SEC61A1 feedback loop contributed to the progression of colon adenocarcinoma.

Asperflotone, an 8(14→15)- abeo-Ergostane from the Sponge-Derived Fungus Aspergillus flocculosus 16D-1.

A novel 8(14→15)- abeo-ergostane-type steroid, asperflotone (1), and an ergostane steroid, asperfloroid (2), were isolated from the solid culture of Aspergillus flocculosus 16D-1. Their structures and absolute configurations were determined by high-resolution electrospray ionization mass spectrometry, 1D/2D NMR, X-ray crystallography, and quantum chemical calculations. Compound 1 is an unprecedented ergosteroid featuring a rearranged bicyclo[4.2.1]non-2-ene ring system that could result from α-ketol rearrangement during biosynthesis. Compounds 1 and 2 showed inhibitory activity toward IL-6 production in the induced THP-1 cells.