Nanosecond and femtosecond laser ablation of brass: particulate and ICPMS measurements

Femtosecond and nanosecond lasers were compared for ablating brass alloys. All operating parameters from both lasers were equal except for the pulse duration. The ablated aerosol vapor was collected on silicon substrates for particle size measurements or sent into an inductively coupled plasma mass spectrometer. The diameters and size distribution of particulates were measured from scanning electron microscope (SEM) images of the collected ablated aerosol. SEM measurements showed that particles ablated using nanosecond pulses were single spherical entities ranging in diameter from several micrometers to several hundred nanometers. Primary particles ablated using femtosecond ablation were approximately 100 nm in diameter but formed large agglomerates. ICPMS showed enhanced signal intensity and stability using femtosecond compared to nanosecond laser ablation.

Animal and Organoid Models of Liver Fibrosis

Liver fibrosis refers to the process underlying the development of chronic liver diseases, wherein liver cells are repeatedly destroyed and regenerated, which leads to an excessive deposition and abnormal distribution of the extracellular matrix such as collagen, glycoprotein and proteoglycan in the liver. Liver fibrosis thus constitutes the pathological repair response of the liver to chronic injury. Hepatic fibrosis is a key step in the progression of chronic liver disease to cirrhosis and an important factor affecting the prognosis of chronic liver disease. Further development of liver fibrosis may lead to structural disorders of the liver, nodular regeneration of hepatocytes and the formation of cirrhosis. Hepatic fibrosis is histologically reversible if treated aggressively during this period, but when fibrosis progresses to the stage of cirrhosis, reversal is very difficult, resulting in a poor prognosis. There are many causes of liver fibrosis, including liver injury caused by drugs, viral hepatitis, alcoholic liver, fatty liver and autoimmune disease. The mechanism underlying hepatic fibrosis differs among etiologies. The establishment of an appropriate animal model of liver fibrosis is not only an important basis for the in-depth study of the pathogenesis of liver fibrosis but also an important means for clinical experts to select drugs for the prevention and treatment of liver fibrosis. The present study focused on the modeling methods and fibrosis characteristics of different animal models of liver fibrosis, such as a chemical-induced liver fibrosis model, autoimmune liver fibrosis model, cholestatic liver fibrosis model, alcoholic liver fibrosis model and non-alcoholic liver fibrosis model. In addition, we also summarize the research and application prospects concerning new organoids in liver fibrosis models proposed in recent years. A suitable animal model of liver fibrosis and organoid fibrosis model that closely resemble the physiological state of the human body will provide bases for the in-depth study of the pathogenesis of liver fibrosis and the development of therapeutic drugs.

Safety of Endoscopic Resection for Upper Gastrointestinal Subepithelial Tumors Originating from the Muscularis Propria Layer: An Analysis of 733 Tumors

OBJECTIVES

Although endoscopic resection is an accepted technique for upper gastrointestinal subepithelial tumors (SETs) originating from the muscularis propria (MP) layer, published data regarding its complications are highly variable and limited to small data series. This study aimed to analyze the safety of endoscopic resection in a large case series.

METHODS

A total of 726 consecutive patients with 733 upper gastrointestinal SETs originating from the MP layer underwent endoscopic resection from June 2005 to December 2014. The complete resection rate, perioperative perforation rate, and perioperative bleeding rate were the main outcome measurements.

RESULTS

The complete resection rate was 97.1%. Ninety-four patients had complications (12.9%), including 88 with perioperative perforations (12.1%), 13 with perioperative bleeding (1.8%), 5 with localized peritonitis (0.7%), and one with delayed bleeding (0.1%). Eleven patients required surgery; the others were treated endoscopically. Risk factors for incomplete resection were extensive connection of the tumor to the MP layer (P=0.007) and extraluminal growth (P=0.048). Risk factors for perioperative perforation were larger tumor size (≤2.0 cm vs. 2.1-3.0 cm vs. >3.0 cm, P=0.021), extraluminal growth (P=0.046), and extensive connection (P<0.001). A risk factor for perioperative bleeding was larger tumor size (P=0.045). No residual or recurrent lesions were detected during the follow-up period (median: 28 months).

CONCLUSIONS

Endoscopic resection is an effective and reasonably safe therapeutic method for treating/removing upper gastrointestinal SETs originating from the MP layer when managed by an experienced endoscopic team.

Long-term outcomes of endoscopic resection for small (≤ 4.0 cm) gastric gastrointestinal stromal tumors originating from the muscularis propria layer

AIM

To evaluate the long-term efficacy of endoscopic resection (ER) for small (≤ 4.0 cm) gastric gastrointestinal stromal tumors (GISTs) originating from the muscularis propria layer.

METHODS

Between June 2005 and February 2015, we retrospectively analyzed 229 consecutive patients with gastric MP-GISTs who underwent ER with a follow-up at least 36 mo. The main outcome measurements included complete resection rate, complications, and long-term follow-up outcomes.

RESULTS

ER included endoscopic muscularis excavation in 179 cases, endoscopic full-thickness resection in 32 cases, and submucosal tunneling endoscopic resection in 18 cases. The median size of GISTs was 1.90 cm. Of the 229 GISTs, 147 were very low risk, 72 were low risk, 8 were intermediate risk, and 2 were high risk. Short-term outcomes showed the complete resection rate was 96.5%, and 8 patients (3.5%) had complications. Of the 8 patients with complications, only one patient required surgical intervention. Long-term outcomes showed 225 patients were actively followed-up until composition of this manuscript. The remaining 4 patients were lost because of unrelated death. During the follow-up period (median, 57 mo), no residual, recurrent lesions, or distant metastasis were detected in any patients. Binary logistic regression analysis showed tumor size was a risk factor associated with a high mitotic index (≥ 5/50 HPF) of GISTs (P = 0.002).

CONCLUSION

ER seems to be an effective and safe method for gastric MP-GISTs ≤ 4.0 cm, and, for some intermediate or high risk GISTs, adjuvant therapy and/or additional surgery might be required to reduce the risk of recurrence or metastasis.

Rapid and sensitive detection of Singapore grouper iridovirus by loop-mediated isothermal amplification

AIMS

The aim of this paper was to develop a loop-mediated isothermal amplification (LAMP) method for rapid, sensitive and inexpensive detection of Singapore grouper iridovirus (SGIV) in grouper (GP), Epinephelus sp.

METHODS AND RESULTS

A set of six specific primers was designed by targeting the SGIV ORF-014L. With Bst DNA polymerase large fragment, the target DNA can be amplified as early as 20 min at 65 degrees C in a simple water bath. The detection limit is about 0.02 fg (equivalent to 6.3 copies) of plasmid ORF-014L. LAMP products could be judged with three different methods. There were no cross-reactions with seven other aquatic animal viruses indicating high specificity of the LAMP. The LAMP method was applied to detect SGIV in virus-infected GP cells and GP tissues effectively.

CONCLUSIONS

The LAMP described in this study is a cheap, sensitive, specific and rapid protocol for the detection of SGIV in cells and in GP tissues.

SIGNIFICANCE AND IMPACT OF THE STUDY

The developed LAMP method can be simply applied both in field condition and in laboratory operation for specific detection of SGIV infection.

Endoscopic treatments for small gastric subepithelial tumors originating from muscularis propria layer

Minimally invasive endoscopic resection has become an increasingly popular method for patients with small (less than 3.5 cm in diameter) gastric subepithelial tumors (SETs) originating from the muscularis propria (MP) layer. Currently, the main endoscopic therapies for patients with such tumors are endoscopic muscularis excavation, endoscopic full-thickness resection, and submucosal tunneling endoscopic resection. Although these endoscopic techniques can be used for complete resection of the tumor and provide an accurate pathological diagnosis, these techniques have been associated with several negative events, such as incomplete resection, perforation, and bleeding. This review provides detailed information on the technical details, likely treatment outcomes, and complications associated with each endoscopic method for treating/removing small gastric SETs that originate from the MP layer.

Complete circular endoscopic resection using submucosal tunnel technique combined with esophageal stent placement for circumferential superficial esophageal lesions

BACKGROUND AND AIMS

At present, removing a circumferential superficial esophageal lesion (SEL) via en bloc resection is still a great challenge. Based on the previous success of submucosal tunneling endoscopic resection, this study aimed to evaluate the safety and effectiveness of complete circular endoscopic resection (CER) using a submucosal tunnel technique combined with esophageal stent placement for patients with circumferential SELs.

METHODS

From August 2012 to June 2014, 23 patients with circumferential SELs were treated by CER using a submucosal tunnel technique combined with esophageal stent placement. The following steps were performed: (1) circular mucosa incisions were made at the anal and oral side of the lesion after marking the margin, (2) two submucosal tunnels were created from the oral to anal side using a hybrid knife, which was followed by submucosal dissection, and (3) following the completion of CER, a retrievable esophageal stent was placed to prevent postoperative stricture.

RESULTS

CER using the submucosal tunnel technique combined with esophageal stent placement was successfully performed for all 23 cases. The complete resection and success rate were 100%, while the mean longitudinal diameter of the lesions was 65 mm. Mediastinal emphysema, pneumothorax, and postoperative stenosis were detected in 8.7% (2/23), 4.3% (1/23), and 17.4% (4/23) of the cases, respectively. Pathological diagnoses of the lesions included carcinomas (13/23) and high-grade intraepithelial neoplasias (10/23). No residual or recurrent tumors were detected in any patient during the follow-up period.

CONCLUSIONS

CER using the submucosal tunnel technique combined with esophageal stent placement seems to be a safe and effective procedure for treating patients with SELs that result in a higher en bloc resection rate with fewer or minor complications.

MiR-542-3p controls hepatic stellate cell activation and fibrosis via targeting BMP-7

There has been an increasing number of studies about microRNAs as key regulators in the development of hepatic fibrosis. Here, we demonstrate that miR-542-3p can promote hepatic fibrosis by downregulating the expression of bone morphogenetic protein 7 (BMP-7), which is known to antagonize transforming growth factor β1 (TGFβ1)-mediated fibrogenesis effect. The expression of miR-542-3p is increased in activated hepatic stellate cells (HSCs). Downregulation of MiR-542-3p by antisense inhibitors can inhibit HSCs activation markers, including α-smooth muscle actin (α-SMA) and collagen as well as TGFβ signaling pathways. MiR-542-3p was significantly upregulated in carbon tetrachloride (CCl₄ )-induced hepatic fibrosis in mice, and downregulation of miR-542-3p by lentivirus could prevent the development of hepatic fibrosis. In addition, miR-542-3p can directly bind to the 3'-untranslated region of BMP-7 mRNA, indicating that its profibrotic effect appears to be caused by its inhibition of BMP-7. Our results suggest that downregulation of miR-542-3p prevents liver fibrosis both in vitro and in vivo, highlighting its potential as a novel biomarker or therapeutic target for hepatic fibrosis.

Novel Targets and Therapeutic Strategies to Protect Against Hepatic Ischemia Reperfusion Injury

Hepatic ischemia reperfusion injury (IRI), a fascinating topic that has drawn a lot of interest in the last few years, is a major complication caused by a variety of clinical situations, such as liver transplantation, severe trauma, vascular surgery, and hemorrhagic shock. The IRI process involves a series of complex events, including mitochondrial deenergization, metabolic acidosis, adenosine-5'-triphosphate depletion, Kupffer cell activation, calcium overload, oxidative stress, and the upregulation of pro-inflammatory cytokine signal transduction. A number of protective strategies have been reported to ameliorate IRI, including pharmacological therapy, ischemic pre-conditioning, ischemic post-conditioning, and machine reperfusion. However, most of these strategies are only at the stage of animal model research at present, and the potential mechanisms and exact therapeutic targets have yet to be clarified. IRI remains a main cause of postoperative liver dysfunction, often leading to postoperative morbidity or even mortality. Very recently, it was reported that the activation of peroxisome proliferator-activated receptor γ (PPARγ), a member of a superfamily of nuclear transcription factors activated by agonists, can attenuate IRI in the liver, and FAM3A has been confirmed to mediate the protective effect of PPARγ in hepatic IRI. In addition, non-coding RNAs, like LncRNAs and miRNAs, have also been reported to play a pivotal role in the liver IRI process. In this review, we presented an overview of the latest advances of treatment strategies and proposed potential mechanisms behind liver IRI. We also highlighted the role of several important molecules (PPARγ, FAM3A, and non-coding RNAs) in protecting against hepatic IRI. Only after achieving a comprehensive understanding of potential mechanisms and targets behind IRI can we effectively ameliorate IRI in the liver and achieve better therapeutic effects.

Liver injury in COVID-19: Detection, pathogenesis, and treatment

In the early December 2019, a novel coronavirus named severe acute respiratory syndrome coronavirus 2 was first reported in Wuhan, China, followed by an outbreak that spread around the world. Numerous studies have shown that liver injury is common in patients with coronavirus disease 2019 (COVID-19), and may aggravate the severity of the disease. However, the exact cause and specific mechanism of COVID-associated liver injury needs to be elucidated further. In this review, we present an analysis of the clinical features, potential mechanisms, and treatment strategies for liver injury associated with COVID-19. We hope that this review would benefit clinicians in devising better strategies for management of such patients.

Safety of endoscopic resection for duodenal subepithelial lesions with wound closure using clips and an endoloop: an analysis of 68 cases

BACKGROUND

Endoscopic removal of a duodenal lesion is still considered to be a challenging procedure that can be fraught with potentially serious complications, specifically perforation or delayed bleeding. This study was to assess the safety of endoscopic resection for duodenal subepithelial lesions (SELs) with wound closure using clips and an endoloop.

METHODS

From October 2010 to July 2015, a total of 68 consecutive patients with duodenal SELs were treated with endoscopic resection with wound closure using clips and an endoloop. The main outcome measures considered were the incidence of complete resection, perioperative perforation, delayed perforation, delayed bleeding, residual lesions, and lesion recurrence.

RESULTS

Complete resection was successfully achieved for all 68 patients. The median lesion size was 1.7 cm. The median procedure time was 62 min. The mean hospital stay was 5.5 days. During the procedure, five patients developed perioperative perforations (7.4 %) and no patients developed delayed bleeding, delayed perforation, or other serious complications. The five patients with perioperative perforations recovered after conservative treatment. The perioperative perforation rate was significantly higher for lesions originating in the muscularis propria layer (18.2 %) than in the submucosal layer (2.2 %; p < 0.05). No residual or recurrent lesions were detected during the follow-up period (median: 27 months).

CONCLUSIONS

Endoscopic resection with wound closure using clips and an endoloop is an effective and reasonably safe therapeutic method for treating/removing duodenal SELs when managed by an experienced endoscopic team, and it can provide an alternative treatment option for patients with duodenal SELs.

Endoscopic retrograde appendicitis techniques for the treatment of patients with acute appendicitis

OBJECTIVE

The purpose of this study was to demonstrate the feasibility of endoscopic retrograde appendicitis therapy (ERAT) in treating patients with acute appendicitis.

MATERIALS AND METHODS

Between January 2014 and December 2014, 22 patients with acute appendicitis underwent ERAT. Patient demographics, colonoscopy findings, endoscopic retrograde appendiceal radiography (ERAR) findings, and treatment outcomes of the ERAT and adverse events associated with ERAT were analyzed.

RESULTS

In this study, 22 patients with acute appendicitis underwent ERAT. The median age of the patients was 39.5 years. Colonoscopy findings included mucosal hyperemia and swelling of the appendiceal orifice and/or its surrounding mucosa (86.4 %, 19/22) and pus at the appendiceal orifice (40.9 %, 9/22). ERAR findings included irregular contour (76.2 %, 16/21), appendiceal lumen dilation (28.6 %, 6/21), appendiceal lumen stenosis (42.9 %, 9/21), and filling defect of the appendiceal lumen (23.8 %, 5/21). Deep intubation was successfully performed in 21 of the 22 patients (95.5 %). Sixteen patients underwent endoscopic appendiceal stent placement after endoscopic appendiceal irrigation (EAI) due to lumen stenosis of the appendiceal, excessive pus, or appendiceal fecalith, and the remaining 6 patients only underwent EAI. Among the 22 patients who underwent ERAT, their abdominal pain was noticeably relieved following the procedure. The main adverse events associated with ERAT were spontaneous discharge of the stent, recurrent abdominal pain, and recurrent appendicitis. During the follow-up (median 33 months), 2 patients underwent laparoscopic appendectomy.

CONCLUSIONS

ERAT provide a new alternative therapeutic method for patients with acute appendicitis, particularly for certain patients who are unwilling to undergo an appendectomy.

The Dark Side of Pyroptosis of Diffuse Large B-Cell Lymphoma in B-Cell Non-Hodgkin Lymphoma: Mediating the Specific Inflammatory Microenvironment

Background: Diffuse large B-cell lymphoma (DLBCL) is a common aggressive B-cell non-Hodgkin lymphoma (B-NHL). While combined chemotherapy has improved the outcomes of DLBCL, it remains a highly detrimental disease. Pyroptosis, an inflammatory programmed cell death, is considered to have both tumor-promoting and tumor-suppressing effects. The role of pyroptosis in DLBCL has been gradually appreciated, but its value needs further investigation.

Methods: We analyzed mutations and copy number variation (CNV) alterations of pyroptosis-related genes (PRGs) from The Cancer Genome Atlas (TCGA) cohort and evaluated the differences in expression in normal B cells and DLBCL patients in two Gene Expression Omnibus (GEO) datasets (GSE12195 and GSE56315). Based on the expression of 52 PRGs, we divided 421 DLBCL patients from the GSE31312 dataset into distinct clusters using consensus clustering. The Kaplan-Meier method was used to prognosis among the three clusters, and GSVA was used to explore differences in the biological functions. ESTIMATE and single-sample gene-set enrichment analysis (ssGSEA) were used to analyze the tumor immune microenvironment (TME) in different clusters. A risk score signature was developed using a univariate survival analysis and multivariate regression analysis, and the reliability and validity of the signature were verified. By combining the signature with clinical factors, a nomogram was established to predict the prognosis of DLBCL patients. The alluvial diagram and correlation matrix were used to explore the relationship between pyroptosis risk score, clinical features and TME.

Results: A large proportion of PRGs are dysregulated in DLBCL and associated with the prognosis. We found three distinct pyroptosis-related clusters (cluster A, B, and C) that differed significantly with regard to the prognosis, biological process, clinical characteristics, chemotherapeutic drug sensitivity, and TME. Furthermore, we developed a risk score signature that effectively differentiates high and low-risk patients. The nomogram combining this signature with several clinical indicators showed an excellent ability to predict the prognosis of DCBCL patients.

Conclusions: This work demonstrates that pyroptosis plays an important role in the diversity and complexity of the TME in DLBCL. The risk signature of pyroptosis is a promising predictive tool. A correct and comprehensive assessment of the mode of action of pyroptosis in individuals will help guide more effective treatment.

A novel xylene substitute for histotechnology and histochemistry

Propylene glycol methyl ether (PGME) exhibits excellent solvent and coupling properties. A toxicity database provided evidence suggesting that PGME might be a useful substitute for xylene in histotechnology and histochemistry applications. Tissue specimens were fixed, cleared in either PGME or xylene, embedded in paraffin wax, then dewaxed in either PGME or xylene. Sections were treated with the following stains: hematoxylin & eosin (H & E), three special stains of the Gordon/Sweet silver staining method, PAS, and Masson's trichrome, and immunostains including actin, CD3, CD34, CK, CK7/CK9, Ki-67, and ER/PR. The sections were mounted in a resinous medium consisting of PGME and pinene copolymer, then examined under a microscope. Variables such as water tolerance, dimension change, organic solvency, and anti-fading efficacy also were assessed. Depending on the application, PGME performance was equal to or exceeded that of xylene. PGME provided better optical clarity and nuclear detail, did not harden the tissue samples, conserved tissue antigenicity, and was amenable to resinous mounting. Tissues not dehydrated with absolute ethanol also were processed properly. Tissues treated with PGME did not warp or contract compared to those treated with xylene (p < 0.0001). PGME, however, exhibited less organic solvency than xylene. There was no discernible change in the colors of stains in sections processed with PGME even after storage for two years. These results suggest that PGME is a novel xylene substitute for applications in histotechnology and histochemistry.

Submucosal tunneling endoscopic resection using methylene-blue guidance for cardial subepithelial tumors originating from the muscularis propria layer

Submucosal tunneling endoscopic resection (STER) of subepithelial tumors (SETs) originating from the muscularis propria (MP) layer in the cardia is rarely performed due to the difficulty of creating a submucosal tunnel for resection. The aim of this study was to evaluate the feasibility of STER using methylene-blue guidance for SETs originating from the MP layer in the cardia. From January 2012 to December 2014, 56 patients with SETs originating from the MP layer in the cardia were treated with STER using methylene-blue guidance. The complete resection rate and adverse event rate were the main outcome measurements. Successful complete resection by STER was achieved in all 56 cases (100%). The median size of the tumor was 1.8 cm. Nine patients (15.3%) had adverse events including subcutaneous emphysema, pneumoperitoneum, pneumothorax, and pleural effusion. These nine patients recovered successfully after conservative treatment without endoscopic or surgical intervention. No residual or recurrent tumors were detected in any patient during the follow-up period (median, 25 months). The adverse event rate was significantly higher for tumors originating in the deeper MP layers (46.7%) than in the superficial MP layers (4.9%) (P < 0.05), differed significantly according to tumor size (5.4% for tumors < 2.0 cm vs. 36.8% for tumors ≥ 2.0 cm; P < 0.05), and also differed significantly in relation to the tumor growth pattern (4.1% for the intraluminal growth vs. 100% for the extraluminal growth; P < 0.001). STER using methylene-blue guidance appears to be a feasible method for removing SETs originating from the MP layer in the cardia.

Progress of esophageal stricture prevention after endoscopic submucosal dissection by regenerative medicine and tissue engineering

Endoscopic submucosal dissection (ESD) has been widely accepted as an effective treatment for early esophageal cancer. However, post-ESD esophageal stricture remains a thorny issue. We herein review many strategies for preventing post-ESD esophageal stricture, as well as discuss their strengths and weaknesses. These strategies include pharmacological prophylaxis, esophageal stent and tissue engineering and regenerative medicine treatment. In this review, we summarize these studies and discuss the underlying progress and future directions of tissue engineering and regenerative medicine treatment.

Endoscopic resection of large (≥ 4 cm) upper gastrointestinal subepithelial tumors originating from the muscularis propria layer: a single-center study of 101 cases (with video)

BACKGROUND AND AIMS

Although endoscopic resection (ER) is already established as a minimally invasive technique for small (< 4.0 cm) upper gastrointestinal subepithelial tumors originating from the muscularis propria layer (MP-SETs), published data of ER for large (≥ 4.0 cm) upper gastrointestinal MP-SETs are extremely rare and limited to case reports. This retrospective study aimed to evaluate the feasibility and safety of ER for large (≥ 4.0 cm) upper gastrointestinal MP-SETs in a large case series.

METHODS

Between June 2012 and December 2018, 101 patients with large (≥ 4 cm) upper gastrointestinal MP-SETs were enrolled in this study. The main outcome measures included complete resection, total complications, and local residual or recurrent tumor.

RESULTS

The rate of complete resection was 86.1%. Thirteen patients (12.9%) experienced complications including gas-related complications (6/101, 5.9%), localized peritonitis (4/101, 4.0%), esophageal/cardiac mucosal laceration (2/101, 2.0%), and delayed bleeding (1/101, 1.0%). These 13 patients recovered after endoscopic and conservative treatment. The independent risk factor for incomplete resection was tumor size (P = 0.005), and the independent risk factors for total complications were tumor size (P = 0.011) and tumor extraluminal growth (P = 0.037). During the median follow-up of 36 months, local residual tumor was detected in 1 patient. No local recurrence occurred in any patient.

CONCLUSIONS

Despite being associated with a relatively low complete resection rate, ER is an alternative therapeutic method for large (≥ 4.0 cm) upper gastrointestinal MP-SETs when performed by an experienced endoscopist. This method is especially valuable for patients who are unwilling to undergo surgery.

Role of ferroptosis in colorectal cancer

Colorectal cancer (CRC) is the second deadliest cancer and the third-most common malignancy in the world. Surgery, chemotherapy, and targeted therapy have been widely used to treat CRC, but some patients still develop resistance to these treatments. Ferroptosis is a novel non-apoptotic form of cell death. It is an iron-dependent non-apoptotic cell death characterized by the accumulation of lipid reactive oxygen species and has been suggested to play a role in reversing resistance to anticancer drugs. This review summarizes recent advances in the prognostic role of ferroptosis in CRC and the mechanism of action in CRC.

Rational Molecular Design of Potent PLK1 PBD Domain-binding Phosphopeptides Using Preferential Amino Acid Building Blocks

Polo-like kinase 1 (PLK1) is an important regulator in diverse aspects of the cell cycle and proliferation. The protein has a highly conserved polo-box domain (PBD) present in C-terminal noncatalytic region, which exhibits a relatively broad sequence specificity in recognizing and binding phosphorylated substrates to control substrate phosphorylation by the kinase. In order to elucidate the structural basis, thermodynamic property, and biological implication underlying PBD-substrate recognition and association, a systematic amino acid preference profile of phosphopeptide interaction with PLK1 PBD domain was established via virtual mutagenesis analysis and mutation energy calculation, from which the contribution of different amino acids at each residue position of two reference phosphopeptides to domain-peptide binding was characterized comprehensively and quantitatively. With the profile, we are able to determine the favorable, neutral, and unfavorable amino acid types for each position of PBD-binding phosphopeptides, and we also explored the molecular origin of the broad sequence specificity in PBD-substrate recognition. To practice computational findings, the profile was further employed to guide rational design of potent PBD binders; three 6-mer phosphopeptides (i.e., IQSpSPC, LQSpTPF, and LNSpTPT) were successfully developed, which can efficiently target PBD domain with high affinity (Kd = 5.7 ± 1.1, 0.75 ± 0.18, and 7.2 ± 2.6 μm, resp.) as measured by a fluorescence anisotropy assay. The complex structure of PLK1 PBD domain with a newly designed, potent phosphopeptide LQSpTPF as well as diverse noncovalent chemical forces, such as H-bonds and hydrophobic interactions at the complex interface, were examined in detail to reveal the molecular mechanism of high affinity and stability of the complex system.

Use of Artificial Intelligence to Improve the Quality Control of Gastrointestinal Endoscopy

With the rapid development of science and technology, artificial intelligence (AI) systems are becoming ubiquitous, and their utility in gastroenteroscopy is beginning to be recognized. Digestive endoscopy is a conventional and reliable method of examining and diagnosing digestive tract diseases. However, with the increase in the number and types of endoscopy, problems such as a lack of skilled endoscopists and difference in the professional skill of doctors with different degrees of experience have become increasingly apparent. Most studies thus far have focused on using computers to detect and diagnose lesions, but improving the quality of endoscopic examination process itself is the basis for improving the detection rate and correctly diagnosing diseases. In the present study, we mainly reviewed the role of AI in monitoring systems, mainly through the endoscopic examination time, reducing the blind spot rate, improving the success rate for detecting high-risk lesions, evaluating intestinal preparation, increasing the detection rate of polyps, automatically collecting maps and writing reports. AI can even perform quality control evaluations for endoscopists, improve the detection rate of endoscopic lesions and reduce the burden on endoscopists.

Identification and Validation of a Novel RNA-Binding Protein-Related Gene-Based Prognostic Model for Multiple Myeloma

Background

Multiple myeloma (MM) is a malignant hematopoietic disease that is usually incurable. RNA-binding proteins (RBPs) are involved in the development of many tumors, but their prognostic significance has not been systematically described in MM. Here, we developed a prognostic signature based on eight RBP-related genes to distinguish MM cohorts with different prognoses.

Method

After screening the differentially expressed RBPs, univariate Cox regression was performed to evaluate the prognostic relevance of each gene using The Cancer Genome Atlas (TCGA)-Multiple Myeloma Research Foundation (MMRF) dataset. Lasso and stepwise Cox regressions were used to establish a risk prediction model through the training set, and they were validated in three Gene Expression Omnibus (GEO) datasets. We developed a signature based on eight RBP-related genes, which could classify MM patients into high- and low-score groups. The predictive ability was evaluated using bioinformatics methods. Gene ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment, and gene set enrichment analyses were performed to identify potentially significant biological processes (BPs) in MM.

Result

The prognostic signature performed well in the TCGA-MMRF dataset. The signature includes eight hub genes: HNRNPC, RPLP2, SNRPB, EXOSC8, RARS2, MRPS31, ZC3H6, and DROSHA. Kaplan-Meier survival curves showed that the prognosis of the risk status showed significant differences. A nomogram was constructed with age; B2M, LDH, and ALB levels; and risk status as prognostic parameters. Receiver operating characteristic (ROC) curve, C-index, calibration analysis, and decision curve analysis (DCA) showed that the risk module and nomogram performed well in 1, 3, 5, and 7-year overall survival (OS). Functional analysis suggested that the spliceosome pathway may be a major pathway by which RBPs are involved in myeloma development. Moreover, our signature can improve on the R-International Staging System (ISS)/ISS scoring system (especially for stage II), which may have guiding significance for the future.

Conclusion

We constructed and verified the 8-RBP signature, which can effectively predict the prognosis of myeloma patients, and suggested that RBPs are promising biomarkers for MM.

Effectiveness and safety of over-the-scope clip in closing perforations after duodenal surgery

BACKGROUND

Endoscopic resection of duodenal subepithelial lesions (SELs) is a difficult procedure with a high risk of perforation. At present, dealing with perforation after endoscopic resection of duodenal SELs is still considered a great challenge.

AIM

To evaluate the effectiveness and safety of an over-the-scope clip (OTSC) in the treatment of perforation post-endoscopic resection of duodenal SELs.

METHODS

From May 2015 to November 2019, 18 patients with perforation following endoscopic resection of duodenal SELs were treated with OTSCs. Data comprising the rate of complete resection, closure of intraprocedural perforation, delayed bleeding, delayed perforation, and postoperative infection were extracted.

RESULTS

The rate of complete removal of duodenal SELs and successful closure of the perforation was 100%. The median perforation size was 1 cm in diameter. Seventeen patients had minor intraoperative bleeding, while the remaining 1 patient had considerable amount of bleeding during the procedure. Seven patients had postoperative abdominal infections, of which 1 patient developed an abscess in the right iliac fossa and another patient developed septic shock. All 18 patients recovered and were discharged. No delayed bleeding or perforation was reported. The mean time taken to resume normal diet after the procedure was 6.5 d. The mean postoperative hospital stay was 9.5 d. No residual or recurrent lesions were detected during the follow-up period (15-66 mo).

CONCLUSION

Closing a perforation after endoscopic resection of duodenal SELs with OTSCs seems to be an effective and reasonably safe therapeutic method.

Revisiting the structural basis and energetic landscape of susceptibility difference between HLA isotypes to allergic rhinitis

The human leukocyte antigen class II (HLA II) molecules are implicated in the immunopathogenesis of allergic rhinitis (AR). The HLA II contains three allelic isotypes HLA-DR, -DQ, and -QP that exhibit considerably different susceptibility to AR. Here, we investigated the structural basis and energetic landscape of the susceptibility difference between the three HLA II isotypes to AR by combining computational analysis and experimental assay. Multiple sequence alignment revealed a low conservation among the three subtypes with sequence identity of ∼10% between them, suggesting that the peptide repertoires presented by HLA-DR, -DP and -DQ are not overlapped to each other, and they may be involved in different immune functions and dysfunctions. Structural analysis imparted that the antigenic peptides are rooted on the peptide-binding groove of HLA molecules and hold in a PPII-like helical conformation. Subsequently, the interaction behavior of 17 AR allergen-derived peptides with HLA-DR, -DP and -DQ was investigated using a statistics-based quantitative structure-activity relationship (QSAR) predictor. It was found a significant difference between the binding capabilities of these antigenic peptides to HLA-DR and to HLA-DP/-DQ; the former showed a generally higher affinity than the latter with p-value of 0.02 obtained from 2-tailed Student's t-test. The computational findings were then confirmed by HLA II-peptide stability assay, which demonstrated that the AR allergen-derived peptides have a high in vitro selectivity for HLA-DR over HLA-DP/-DQ. Thus, the HLA-DR isotype, rather than HLA-DP and -DQ, is expected to associate with the pathological process of AR.

Cost-effective low-coverage whole-genome sequencing assay for the risk stratification of gastric cancer

BACKGROUND

Gastric cancer (GC), a multifactorial disease, is caused by pathogens, such as Helicobacter pylori (H. pylori) and Epstein-Barr virus (EBV), and genetic components.

AIM

To investigate microbiomes and host genome instability by cost-effective, low-coverage whole-genome sequencing, as biomarkers for GC subtyping.

METHODS

Samples from 40 GC patients were collected from Taizhou Hospital, Zhejiang Province, affiliated with Wenzhou Medical University. DNA from the samples was subjected to low-coverage whole-genome sequencing with a median genome coverage of 1.86 × (range: 1.03 × to 3.17 ×) by Illumina × 10, followed by copy number analyses using a customized bioinformatics workflow ultrasensitive chromosomal aneuploidy detector.

RESULTS

Of the 40 GC samples, 20 (50%) were found to be enriched with microbiomes. EBV DNA was detected in 5 GC patients (12.5%). H. pylori DNA was found in 15 (37.5%) patients. The other 20 (50%) patients were found to have relatively higher genomic instability. Copy number amplifications of the oncogenes, ERBB2 and KRAS, were found in 9 (22.5%) and 7 (17.5%) of the GC samples, respectively. EBV enrichment was found to be associated with tumors in the gastric cardia and fundus. H. pylori enrichment was found to be associated with tumors in the pylorus and antrum. Tumors with elevated genomic instability showed no localization and could be observed in any location. Additionally, H. pylori-enriched GC was found to be associated with the Borrmann type II/III and gastritis history. EBV-enriched GC was not associated with gastritis. No statistically significant correlation was observed between genomic instability and gastritis. Furthermore, these three different molecular subtypes showed distinct survival outcomes (P = 0.019). EBV-positive tumors had the best prognosis, whereas patients with high genomic instability (CIN+) showed the worst survival. Patients with H. pylori infection showed intermediate prognosis compared with the other two subtypes.

CONCLUSION

Thus, using low-coverage whole-genome sequencing, GC can be classified into three categories based on disease etiology; this classification may prove useful for GC diagnosis and precision medicine.