Peroral endoscopic myotomy assisted with an elastic ring for achalasia with obvious submucosal fibrosis: A case report.

BACKGROUND: Peroral endoscopic myotomy (POEM) is an established treatment option for esophageal achalasia. However, technical challenges and failures exist. Submucosal fibrosis is a rare cause of aborted POEM procedures. CASE SUMMARY: We performed POEM with an elastic ring for achalasia with obvious submucosal fibrosis. The short-term outcome was excellent, surgery time was significantly shorter, and success rate was higher with POEM for achalasia with obvious submucosal fibrosis. CONCLUSION: POEM performed with an elastic ring is a feasible and effective endoscopic treatment modality for achalasia with obvious submucosal fibrosis.

Structural insights into molecular mechanism for N6-adenosine methylation by MT-A70 family methyltransferase METTL4.

METTL4 belongs to a subclade of MT-A70 family members of methyltransferase (MTase) proteins shown to mediate N6-adenosine methylation for both RNA and DNA in diverse eukaryotes. Here, we report that Arabidopsis METTL4 functions as U2 snRNA MTase for N6-2'-O-dimethyladenosine (m6Am) in vivo that regulates flowering time, and specifically catalyzes N6-methylation of 2'-O-methyladenosine (Am) within a single-stranded RNA in vitro. The apo structures of full-length Arabidopsis METTL4 bound to S-adenosyl-L-methionine (SAM) and the complex structure with an Am-containing RNA substrate, combined with mutagenesis and in vitro enzymatic assays, uncover a preformed L-shaped, positively-charged cavity surrounded by four loops for substrate binding and a catalytic center composed of conserved residues for specific Am nucleotide recognition and N6-methylation activity. Structural comparison of METTL4 with the mRNA m6A enzyme METTL3/METTL14 heterodimer and modeling analysis suggest a catalytic mechanism for N6-adenosine methylation by METTL4, which may be shared among MT-A70 family members.

Application of in vivo traction-assisted resection of proximal colon lesions: a case series (with video).

BACKGROUND: Endoscopic submucosal dissection (ESD) is the treatment of choice for colorectal neoplasms in Japan. ESD can completely peel off the lesion and is associated with a significantly lower recurrence rate of colorectal cancers than EMR and is widely used to treat gastrointestinal tumors. This study aimed to evaluate in vivo traction in endoscopic submucosal dissection (ESD) of proximal colon lesions. METHODS: This retrospective study included patients with lesions in the proximal colon who received ESD treatment at Qilu Hospital of Shandong University from June 2018 to December 2020. Patients were divided into two groups according to the in vivo traction method (orthodontic ring or elastic ring) during operation. The operation time, dissection time, proportion of complete resection of lesions, and complications were compared between the two groups. RESULTS: There were 28 patients in this study. In the orthodontic ring group (n = 10), the average lesion diameter was 2.0-2.5 cm, and the average operation and dissection times were 26.5 ± 7.47 and 21.5 ± 7.47 min, respectively. In the elastic ring group (n = 18), the average lesion diameter was 2.5-5.5 cm, and the average operation and dissection times were 27.39 ± 11.83 and 22.39 ± 11.83 min, respectively. All lesions were completely resected in a single operation, and no wound perforation and delayed bleeding occurred. CONCLUSION: In vivo traction-assisted ESD can be used to resect proximal colon lesions in selected patients (precancerous lesions and early colon cancer limited to the mucosa or with a submucosa infiltration depth of < 1000 µm).

Ginsenosides, potent inhibitors of sialyltransferase.

The overexpression of sialic acids and sialyltransferases (STs) during malignant transformation and progression could result in the aberrant sialylation of cancer cells. Therefore, interfering the sialic acid synthesis might be an effective pathway in cancer therapy. In this study, we assessed that the antitumor inhibitors of 20(S)-ginsenosides Rg3, 20(R)-ginsenosides Rg3, 20(S)-ginsenosides Rh2, and 20(R)-ginsenosides Rh2 could block the sialoglycans in liver cancer cells HepG2. The results showed that these four compounds could inhibit the expressions of the total and free sialic acid at different levels in HepG2, respectively; also, it showed dose dependence. In addition, the results of the enzyme-linked immunosorbent assay showed that the above four compounds can inhibit the expression of STs significantly. We also found that these compounds could mediate the block of sialylation of α2,3- and α2,6-linked sialic acids in HepG2 cells by flow cytometry. Meanwhile, the results of the molecular docking investigation showed that these compounds showed strong interaction with ST6GalI and ST3GalI. These results verified that the ginsenosides have a powerful inhibiting aberrant sialylation, and it laid a theoretical foundation for further research on the investigation of ginsenosides as the target inhibitors on STs.

Five novel diarylheptanoids from green walnut husks (Juglans regia L.).

A ethanol extract of green walnut husks (Juglans regia L.) was isolated by various chromatographic techniques yielding 5 previously unknown diarylheptanoids, namely Juglanin F (1), Juglanin G (2), Juglanin H (3), Juglanin I (4) and Juglanin J (5), respectively, together with 12 known diarylheptanoids. The structures of these 17 compounds were elucidation on the basis of spectroscopic analysis. Upon evaluation of compounds 1-5 on the human hepatoma cells HepG2, compound 3 exhibited moderate inhibitory activity with IC50 27.72 µM.