Clinical characteristics of absent contractility and ineffective esophageal motility: a multicenter study in Japan.

BACKGROUND AND AIM: Absent contractility (AC) and ineffective esophageal motility (IEM) are esophageal hypomotility disorders diagnosed using high-resolution manometry (HRM). Patient characteristics and disease course of these conditions and differential diagnosis between AC and achalasia are yet to be elucidated. METHODS: A multicenter study involving 10 high-volume hospitals was conducted. Starlet HRM findings were compared between AC and achalasia. Patient characteristics including underlying disorders and disease courses were analyzed in AC and IEM. RESULTS: Fifty-three patients with AC and 92 with IEM were diagnosed, while achalasia was diagnosed in 1784 patients using the Chicago classification v3.0 (CCv3.0). The cut-off integrated relaxation pressure (IRP) value at 15.7 mmHg showed maximum sensitivity (0.80) and specificity (0.87) for differential diagnosis of AC from type I achalasia. While most ACs were based on systemic disorders such as scleroderma (34%) and neuromuscular diseases (8%), 23% were sporadic cases. The symptom severity of AC was not higher than that of IEM. Regarding the diagnosis of IEM, the more stringent CCv4.0 excluded 14.1% of IEM patients than the CCv3.0, although patient characteristics did not change. In patients with the hypomotile esophagus, concomitance of reflux esophagitis was associated with low distal contractile integral and IRP values. AC and IEM transferred between each other, paralleling with the underlying disease course, although no transition to achalasia was observed. CONCLUSION: A successful determination of the optimal cut-off IRP value was achieved using the starlet HRM system to differentiate AC and achalasia. Follow-up HRM is also useful for differentiating AC from achalasia. Symptom severity may depend on underlying diseases instead of hypomotility severity.

Learning curve for peroral endoscopic myotomy in therapeutic endoscopy experts and nonexperts: Large single-center experience.

OBJECTIVES: Reports on learning curve for peroral endoscopic myotomy (POEM) in therapeutic endoscopy nonexperts are limited. We aimed to assess the number of cases required to achieve POEM proficiency for endoscopic submucosal dissection (ESD) experts and nonexperts. METHODS: This is a retrospective study at the largest POEM referral center in Japan. POEM between April 2014 and December 2020 were included. Nonexperts and ESD experts were divided by training phases: A, 1-20; B, 21-40; C, 41-60; D, 61-80; and E, 81-100 cases. Primary outcome was operation time, and the phase to reach target time (83 min) was investigated. Secondary outcomes were clinical success rate, adverse events, and post-POEM gastroesophageal reflux disease (GERD). RESULTS: Five hundred and sixty-six cases were performed by 14 nonexperts, and 555 cases by 15 ESD experts. As the primary outcome, operation time in nonexperts was: A, 95 (79-115.8); B, 86.5 (71-105); C, 80 (70-100); D, 73 (64.5-100.5); and E, 73.5 (57.8-88.8) min, while in ESD experts: A, 90 (74-128); B, 77 (70-92); and C, 77 (70-93.5) min (median [interquartile range]). Operation time decreased significantly as experience increased in both groups (P < 0.001), and nonexperts required 41-60 cases to achieve proficiency, while experts required 21-40 cases. As secondary outcomes, in nonexperts, clinical success was 96.9-100%, adverse events were 5.0-9.2%, symptomatic GERD was 11.8-26.5%, and proton pump inhibitor (PPI) intake was 11.5-18.7% in each phase. While in experts, clinical success was 96.2-100%, adverse events were 3.0-5.8%, symptomatic GERD was 14.6-22.0%, and PPI intake was 12.6-17.9%. There were no significant differences among training phases. CONCLUSIONS: Non-ESD experts require more cases to achieve proficiency in POEM. These results are useful for establishing POEM training programs and institutional implementation of the procedure.

A novel endoscopic purse-string suture technique, "loop 9", for gastrointestinal defect closure: a pilot study.

BACKGROUND : This study aimed to assess the feasibility and efficacy of the novel loop 9 method of gastrointestinal (GI) defect closure. METHODS : 20 patients underwent a GI procedure that required defect closure. Loop 9 can be delivered through a single instrument channel (3.2 mm) and released at the defect site. After it has been anchored by two clips positioned on opposite sides of the defect edge, the loop 9 is tightened by pulling the end of the suture intraluminally using biopsy forceps. Additional clips are placed to achieve complete closure. The primary outcome was complete closure rate. The secondary outcomes were closure time, sustained closure rate, and adverse events. RESULTS : Complete closure was achieved in 100 % of cases. The mean size of the mucosal defects was 17.5 mm (range 10-55 mm). The median closure time was 14 minutes. The sustained closure rate was 90 %. No adverse events were noted. CONCLUSIONS : The loop 9 technique is feasible and effective in achieving complete and sustained closure of therapeutic endoscopy-related GI defects.

Novel modified side-by-side balloon dilatation method for esophagogastric junction strictures: Single-/double-barrel techniques.

Endoscopic balloon dilatation is an established treatment for benign gastrointestinal strictures. In order to dilatate safely, it is necessary to dilatate gradually and preferably under direct endoscopic visualization. However, it is currently difficult to achieve dilatation widths of 20-30 mm with commercial products and of over 30-mm with endoscopic visualization. Therefore, a safe and innovative application technique is needed for patients who need these 20-mm or greater dilatation widths. We have developed two methods that enable more than 20-mm dilatation under direct visualization. (i) Single-barrel method: an endoscopic balloon dilatation catheter was fixed with grasping forceps at the tip of the endoscope and carried into the stomach. The balloon catheter was released from the endoscope to create a retroflexed view. The endoscope and balloon were positioned adjacent to each other at the gastric cardia. The balloon was inflated gradually and the esophagogastric junction was dilatated under direct visualization. (ii) Double-barrel method: the same procedure was repeated with two balloons. Theoretically, we achieved a dilatation of >30-mm in diameter. These modified methods may be helpful for esophagogastric junction strictures, such as esophageal achalasia (serving as an initial endoscopic balloon dilatation prior to using a 30-mm achalasia balloon), or for functional strictures after Nissen fundoplication. In conclusion, our simple, modified method enables safe and gradual dilatation under direct endoscopic visualization. Additionally, combination of the sizes of one or two balloons can achieve various widths of dilatation.

Identification of functional cytochrome P450 and ferredoxin from Streptomyces sp. EAS-AB2608 by transcriptional analysis and their heterologous expression.

Bioconversion using microorganisms and their enzymes is an important tool in many industrial fields. The discovery of useful new microbial enzymes contributes to the development of industries utilizing bioprocesses. Streptomyces sp. EAS-AB2608, isolated from a soil sample collected in Japan, can convert the tetrahydrobenzotriazole CPD-1 (a selective positive allosteric modulator of metabotropic glutamate receptor 5) to its hydroxylated form at the C4-(R) position. The current study was performed to identify the genes encoding the enzymes involved in CPD-1 bioconversion and to verify their function. To identify gene products responsible for the conversion of CPD-1, we used RNA sequencing to analyze EAS-AB2608; from its 8333 coding sequences, we selected two genes, one encoding cytochrome P450 (easab2608_00800) and the other encoding ferredoxin (easab2608_00799), as encoding desirable gene products involved in the bioconversion of CPD-1. The validity of this selection was tested by using a heterologous expression approach. A bioconversion assay using genetically engineered Streptomyces avermitilis SUKA24 ∆saverm3882 ∆saverm7246 co-expressing the two selected genes (strain ES_SUKA_63) confirmed that these gene products had hydroxylation activity with respect to CPD-1, indicating that they are responsible for the conversion of CPD-1. Strain ES_SUKA_63 also showed oxidative activity toward other compounds and therefore might be useful not only for bioconversion of CPD-1 but also as a tool for synthesis of drug metabolites and in optimization studies of various pharmaceutical lead compounds. We expect that this approach will be useful for bridging the gap between the latest enzyme optimization technologies and conventional enzyme screening using microorganisms. KEY POINTS: • Genes easab2608_00800 (cyp) and easab2608_00799 (fdx) were selected by RNA-Seq. • Selection validity was evaluated by an engineered S. avermitilis expression system. • Strain ES_SUKA_63 showed oxidative activity toward CPD-1 and other compounds.

A novel methymycin analog, 12-ketomethymycin N-oxide, produced by the heterologous expression of the large pikromycin/methymycin biosynthetic gene cluster of Streptomyces sp. AM4900.

A novel methymycin analog, 12-ketomethymycin N-oxide, was produced by the heterologous expression of the pikromycin/methymycin biosynthetic gene cluster of Streptomyces sp. AM4900 together with 12-ketomethymycin, which was only isolated by the biotransformation of the synthetic intermediate before. Their structures were determined by the spectroscopic data and the chemical derivatization. 12-Ketomethymycin showed a weak cytotoxicity against SKOV-3 and Jurkat cells, although its N-oxide analog did not show any activity. Both showed no antibacterial activities against Escherichia coli and Micrococcus luteus.

Distribution and functional analysis of the phosphopantetheinyl transferase superfamily in Actinomycetales microorganisms.

Phosphopantetheinyl transferases (PPTases) are a superfamily of essential enzymes required for the synthetic processes of many compounds including fatty acid, polyketide, and nonribosomal peptide metabolites. These enzymes activate carrier proteins in specific biosynthetic pathways via the transfer of a phosphopantetheinyl moiety to a serine residue in the conserved motif of carrier proteins. Since many Actinomycetales microorganisms produce a number of polyketide and nonribosomal peptide metabolites, the distribution of PPTase genes was investigated in these microorganisms. PPTases were found in bacterial protein databases using a hidden Markov model search with the PF01648 (4'-phosphopantetheinyl transferase superfamily) model. Actinomycetales microorganisms harbor several genes encoding AcpS-type and Sfp-type PPTases in individual genomes, many of which were associated with the biosynthetic gene cluster for polyketide or nonribosomal peptide metabolites. The properties of these PPTases were evaluated in the heterologous expression system using the biosynthetic gene clusters and genes encoding PPTases found in the present study. Sfp-type PPTases were classified into two subgroups, and although the substrate specificities of the enzymes in one subgroup were wide, the catalytic activities of enzymes in the other subgroup were low. SAV_1784 of Streptomyces avermitilis possessed the most characteristic broad-range activity against several type I polyketide synthases and nonribosomal peptide synthetases.

Hydroxylation, Epoxidation, and Dehydrogenation of Capsaicin by a Microbial Promiscuous Cytochrome P450 105D7.

Cytochrome P450 enzymes (P450s) are versatile biocatalysts, which insert a molecular oxygen into inactivated C-H bonds under mild conditions. CYP105D7 from Streptomyces avermitilis has been reported as a bacterial substrate-promiscuous P450 which catalyzes the hydroxylation of 1-deoxypentalenic acid, diclofenac, naringenin, compactin and steroids. In this study, CYP105D7 catalyzes hydroxylation, epoxidation and dehydrogenation of capsaicin, a pharmaceutical agent, revealing its functional diversity. The kinetic parameters of the CYP105D7 oxidation of capsaicin were determined as Km =311.60±87.30 µM and kcat =2.01±0.33 min-1 . In addition, we conducted molecular docking, mutagenesis and substrate binding analysis, indicating that Arg81 plays crucial role in the capsaicin binding and catalysis. To our best knowledge, this study presents the first report to illustrate that capsaicin can be catalyzed by prokaryotic P450s.

Endoscopic treatment of proton pump inhibitor-refractory gastroesophageal reflux disease with anti-reflux mucosectomy: Experience of 109 cases.

OBJECTIVES: Some patients with gastroesophageal reflux disease (GERD) are refractory to proton pump inhibitor (PPI) therapy. Anti-reflux mucosectomy (ARMS) is a minimally invasive endoscopic procedure for treatment of GERD. In this study, we retrospectively evaluated the outcomes of ARMS performed in patients with PPI-refractory GERD at our institution. METHODS: A total of 109 patients with PPI-refractory GERD who underwent ARMS were retrospectively reviewed. Pre- and post-ARMS questionnaire scores, acid exposure time (AET), DeMeester score, proximal extent, and PPI discontinuation rate were compared. RESULTS: There was a significant improvement in the symptom score (P < 0.01) and 40-50% of patients were able to discontinue PPI after ARMS. In patients who were followed up for 3 years, sustained improvement in subjective symptoms was observed. AET and DeMeester score significantly improved after ARMS (P < 0.01); however, there was no significant improvement in proximal extent (P = 0.0846). CONCLUSIONS: Anti-reflux mucosectomy is an effective minimally invasive therapy for patients with PPI-refractory GERD. The therapeutic efficacy is attributable to suppression of acid backflow due to contraction of the scar tissue in cardia.

Simplified endoscopic pressure study integrated system for the diagnosis of gastroesophageal reflux disease.

Endoscopic pressure study integrated system (EPSIS) is a novel tool for the diagnosis of gastroesophageal reflux disease. It enables the evaluation of the function of the lower esophageal sphincter by monitoring intragastric pressure (IGP) while insufflating the stomach during esophagogastroduodenoscopy. EPSIS can predict abnormal acid reflux with high accuracy based on previous studies. IGP was measured by inserting through the working channel of the scope an intragastric catheter connected to a pressure measuring device. Herein, we assess the feasibility of an updated EPSIS system, which can be performed just by connecting a flush tube to the working channel. This method does not require inserting foreign objects in the stomach and spares catheter insertion in order to simplify the procedure and reduce costs. A single-center pilot study was conducted to evaluate the association between catheter-based EPSIS and the updated EPSIS. The results of EPSIS in 20 patients who underwent both methods were assessed. In all cases, the waveform pattern of IGP measured by catheter-based EPSIS and updated EPSIS was consistent with 15 uphill pattern and five flat pattern. Intraobserver agreement of waveform pattern was perfect between two examiners with kappa value = 1. Intraclass correlation coefficient (ICC) for intraobserver reliability for maximum IGP was excellent with 0.91 (95% confidence interval [CI] of 0.77 < ICC < 0.96) and for pressure gradient was also good with 0.89 (95% CI of 0.71 < ICC < 0.95). In conclusion, our study suggests that the updated EPSIS can be performed without the use of a catheter.

Diagnostic yield of fourth-generation endocytoscopy for esophageal squamous lesions using a modified endocytoscopic classification.

OBJECTIVES: Endocytoscopy (EC) is an ultra-high magnification endoscopy designed to provide in vivo histologic assessment. This study aimed to evaluate the diagnostic yield of the newly developed fourth-generation EC for esophageal squamous lesions by using a modified EC classification. METHODS: A total of 2548 EC images of 57 esophageal targeted areas between June 2015 and October 2017 were retrospectively collected. Two lesions with low-quality images were excluded. Only EC images were independently reviewed by two expert and two non-expert endoscopists. The lesions were classified according to a three-tier modified EC classification. We used a multilevel logistic regression to analyze the data. RESULTS: The sensitivity and specificity of diagnosing non-squamous cell cancer (SCC) vs SCC were 82.5% and 83.0% by the experts; 90.1% and 75.0% by non-experts. The interobserver agreement among the four raters was good (kappa statistic 0.59). The diagnostic accuracy of experts and non-experts was similar (P = 0.16 for specificity and P = 0.20 for sensitivity). The sensitivity and specificity of EC for non-neoplasia vs neoplasia were 88.7% and 74.6% by experts; 90.3 and 52.1% by non-experts. The interobserver agreement among the four raters was moderate (kappa statistic 0.44). The specificity of experts was higher compared to non-experts, although the difference did not reach statistical significance (P = 0.08 for specificity and P = 0.93 for sensitivity). CONCLUSIONS: Fourth-generation EC offers acceptable diagnostic accuracy and reliability in both experts and non-experts, especially when diagnosing SCC lesions.

Importance of second-look endoscopy after per-oral endoscopic myotomy for safe postoperative management.

OBJECTIVES: Per-oral endoscopic myotomy (POEM) is a safe and effective treatment for achalasia and esophageal motility disorders. The role of second-look endoscopy (SE) on postoperative day 1 has not been examined. This study aimed to evaluate the findings and need of SE after POEM. METHODS: This is a single-center, retrospective study. All consecutive patients who underwent POEM and SE on postoperative day 1 between December 2017 and September 2019 were included. The primary endpoint was the rate of newly-detected adverse events (nAE) during SE that required endoscopic intervention or deviation from the normal postoperative course. Multivariate logistic regression was used to identify predictors of nAE. RESULTS: Four-hundred-ninety-seven patients (mean age, 50.3 years; female, 49.9%) were included. SE identified abnormal findings in a total of 71 patients (14.3%). nAE which required endoscopic intervention or deviation from the normal postoperative course were identified in 12 patients (2.4%): eight (1.6%) entry site dehiscence; two (0.4%) submucosal hemorrhage or hematoma; and two (0.4%) dehiscence of an intraoperative perforation site after endoclip closure. Other findings such as mucosal thermal damage without perforation and small submucosal hematoma were found in 54 patients (10.9%) and five patients (1.0%), respectively. Multivariate analysis showed that longer operation time and intraoperative adverse events (AE) were associated with clinically significant nAE during SE. CONCLUSIONS: Second-look endoscopy can detect and treat nAE that may lead to severe AE. Thus, SE should be highly considered before starting oral ingestion in all cases, and especially in those who present an intraoperative AE and longer operation time.

Characterization of intragastric pressure waveform in endoscopic pressure study integrated system: Novel diagnostic device for gastroesophageal reflux disease.

OBJECTIVES: Endoscopic pressure study integrated system (EPSIS) is a novel diagnostic tool for gastroesophageal reflux disease (GERD). EPSIS has been developed to evaluate lower esophageal sphincter function by monitoring the intragastric pressure (IGP) while insufflating the stomach during gastroscopy. Based on previous data, EPSIS could diagnose GERD with good accuracy by assessing IGP waveform pattern. This study aimed to further characterize the waveform to improve the diagnostic yield of EPSIS. METHODS: We conducted a retrospective analysis of patients with typical GERD symptoms who underwent both EPSIS and 24-h impedance-pH monitoring (MII-pH) at a single tertiary referral center from October 2018 to May 2020. EPSIS was performed by using a through-the-scope catheter connected to the pressure measuring system (TR-W550, TR-TeH08, AP-C35; Keyence, Osaka, Japan) to monitor IGP. Abnormal acid reflux was defined as acid exposure time (AET) over 6.0%. Pressure waveform was characterized as follows: (i) Basal IGP, (ii) Maximum IGP, (iii) Pressure difference, (iv) Gradient of the waveform. RESULTS: A total of 57 patients with GERD symptoms were analyzed. Twenty-one patients presented abnormal AET on MII-pH. Among EPSIS parameters, pressure difference during insufflation correlated with AET (ρ = -0.66, P < 0.01) and showed the best diagnostic accuracy for AET with the cutoff value of 4.7 mmHg (area under the curve [AUC], 0.87). The gradient of EPSIS waveform also revealed good diagnostic accuracy for abnormal AET with the cutoff value of 0.07 mmHg/s (AUC, 0.81). CONCLUSIONS: Endoscopic pressure study integrated system waveform parameters, especially pressure difference, presented high diagnostic accuracy for the presence of abnormal acid reflux.

Heterologous Expression of the Biosynthetic Gene Cluster for Verticilactam and Identification of Analogues.

Verticilactam and the new geometric isomers, verticilactams B and C, were produced by heterologous expression of the biosynthetic gene cluster for verticilactam using the Streptomyces avermitilis SUKA17 strain. Only verticilactam, a compound with a characteristic ß-ketoamide unit within a 16-membered polyketide macrolactam conjugated with an octalin skeleton, had been previously reported having been isolated from Streptomyces spiroverticillatus JC-8444. In this report, minor verticilactam derivatives were isolated from the transformed strain, and their structures elucidated by spectral analysis. Verticilactam B was a geometric isomer at Δ17 and Δ19, and verticilactam C was the Δ19 and Δ21 isomer. In addition, the absolute configuration of verticilactam was confirmed by ECD analysis and NMR chemical shifts. The stereochemistry assignments of the hydroxy groups at C-10 and C-12 were supported by the domain organization of the polyketide synthase identified in the verticilactam gene cluster. Verticilactam showed moderate activity against the malaria parasite Plasmodium falciparum 3D7 strain with no significant cytotoxicity or antimicrobial effects.

Gastric myotomy length affects severity but not rate of post-procedure reflux: 3-year follow-up of a prospective randomized controlled trial of double-scope per-oral endoscopic myotomy (POEM) for esophageal achalasia.

BACKGROUND: Since Inoue performed the first POEM in 2008, safety and efficacy have been well-established. Early studies focused on refining the technique and avoiding incomplete myotomy. Following the discovery that many patients with abnormal acid exposure are asymptomatic, the focus shifted to post-POEM reflux, but no studies have identified any associated procedural factors. In this study, we examined the intermediate-term results of our previous randomized controlled trial, with particular attention to post-POEM reflux. METHODS: Previously, 100 consecutive patients were randomized to either double- or single-scope POEM. Endoscopy was conducted 2 months post-POEM and annually thereafter. Patients were included in the present study if they completed endoscopy ≥ 6 months post-POEM, and the clinical results of both groups were analyzed with particular attention to clinical efficacy and post-POEM reflux. RESULTS: Median follow-up was 3 years, and most myotomies were performed in the posterior location. The final gastric myotomy length was longer in the double-scope group (3.3 vs. 2.6 cm). Clinical efficacy (≥ 80%) and rates of post-POEM reflux (~ 60%) were similar; however, there was a higher incidence of moderate esophagitis (Los Angeles Grade B) in the double-scope group (25% vs. 4%). There were no cases of severe esophagitis (Los Angeles Grade C/D). Among patients with normal endoscopy at 2 months, > 40% developed erosive esophagitis on intermediate-term follow-up. CONCLUSIONS: This is the first study to demonstrate a procedural factor that increases post-POEM esophagitis. Gastric myotomy > 2.5 cm results in increased rates of moderate esophagitis without improving clinical efficacy. Some patients developed esophagitis in a delayed fashion, emphasizing the importance of ongoing surveillance. We also believe that preserving the gastric sling fibers may help to reduce reflux rates. The double-scope method may help to control myotomy length (2.0-2.5 cm) and direction (lesser curve to avoid the gastric sling) to help maximize clinical efficacy while minimizing post-POEM reflux.

Production of distinct labdane-type diterpenoids using a novel cryptic labdane-like cluster from Streptomyces thermocarboxydus K155.

Bioinformatic mining of the Streptomyces thermocarboxydus K155 genome predicted the presence of four synthases for the production of geosmin, hopene, albaflavenone, and a type B-type A diterpenoid system like that described for labdane-related diterpenoids (LRD). The lrd cluster was comprised by an operon of four genes (lrdABDC). This cluster seemed to be silent in the wild-type strain, as neither labdane nor terpene-like compounds were detected by UPLC-TOF-MS and GC-MS analyses in both culture supernatants and mycelial extracts. Heterologous expression of the lrdABDC cluster in a defective cyslabdan producer (Streptomyces cyslabdanicus K04-0144Δcld) generated 8,17-epoxy-7-hydroxy labda-12,14-diene and cyslabdan. The same cluster expressed in the strains Streptomyces coelicolor M1152, Streptomyces peucetius var. caesius, and Streptomyces avermitilis SUKA22 produced the general intermediary labda-8(17), 12(E),14-triene [(E)-biformene]. Besides (E)-biformene, S. coelicolor M1152 and S. avermitilis SUKA22 produced two and three different labdane-type diterpenoids, underlying the relevance of the genetic background of the Streptomyces host in product formation.

Endoscopic pressure study integrated system reflects gastroesophageal junction competence in patients with erosive esophagitis and Barrett´s esophagus.

OBJECTIVES: The endoscopic pressure study integrated system (EPSIS) is a novel diagnostic tool for gastroesophageal reflux disease (GERD) by monitoring intragastric pressure (IGP). Evaluation of the lower esophageal sphincter (LES) function may be achieved endoscopically by utilizing this newly developed diagnostic tool. This study aimed to evaluate the association between EPSIS results and gastroesophageal reflux-related diseases, e.g., erosive esophagitis (EE) and Barrett's esophagus (BE). METHODS: This was a retrospective, single-center study. All patients who underwent EPSIS between November 2016 and July 2018 were included. EPSIS was performed during esophagogastroduodenoscopy with a dedicated electronic device and a through-the-scope catheter. The maximum IGP (IGP-max) and IGP waveform pattern (flat or uphill) were recorded with this system. Evaluation of an EE and BE was based on the Los Angeles classification and Prague classification, respectively. RESULTS: A total of 104 patients were enrolled; 29 (28%) had EE and 42 (40%) had BE. Patients with EE had lower IGP-max values (16.0 vs 18.8 mmHg, P = 0.01) and an EPSIS flat pattern was seen more frequently (82.8% vs 37.3%, P < 0.001). Similarly, patients with BE displayed a lower IGP-max (15.7 vs 19.6 mmHg, P < 0.001) and presented with an EPSIS flat pattern in a higher proportion (69% vs 37.1%, P < 0.001). These differences remained significant on multivariate analysis. CONCLUSIONS: The EPSIS, as a novel diagnostic tool, was shown to exhibit a relation with EE and BE, implying that EPSIS is a promising modality to evaluate gastroesophageal reflux-related diseases and LES function endoscopically.

Identification of human herpes virus 1 encoded microRNAs in biopsy samples of lower esophageal sphincter muscle during peroral endoscopic myotomy for esophageal achalasia.

Esophageal achalasia is a rare chronic debilitating disorder characterized by incomplete lower esophageal sphincter (LES) relaxation and abnormal peristalsis as a result of myenteric plexus degeneration. Although complex interactions among immunity, viruses and inheritance have been proposed, its causes remain unknown. MicroRNAs (miRs) play crucial roles in the regulation of gene expression during pathophysiological processes. Certain viruses such as herpes simplex virus (HSV) encode miRs derived from their own genomes. To determine the underlying relationship of miRNAs to achalasia, we analyzed the expression profile of miRNAs using biopsy samples obtained from LES muscle during peroral endoscopic myotomy. Peroral LES muscle biopsy sampling was uneventfully carried out in our case series of achalasia. Control biopsy tissues were also obtained from LES muscle of patients without symptoms relating to abnormal esophageal motility whose esophagogastric junction was surgically excised. RNA was extracted from biopsy specimens and analyzed using a microarray. Differentially expressed miRNAs in achalasia patients compared to controls were identified and analyzed using reverse transcription quantitative polymerase chain reaction. HSV-1-derived hsv1-miR-H1 and -H18 was significantly overexpressed in achalasia cohorts compared to controls. Correlations between the expression levels of viral miR and the patients' clinical characteristics including achalasia morphological type, dilatation grading, and disease duration were not identified. Further studies with a larger sample size are needed to replicate the current heuristic identification of neurotropic viral miRs and unravel their functional significance in order to provide new insight linking neurodegenerative etiology in achalasia.

Clinical outcomes of per-oral endoscopic tumor resection for submucosal tumors in the esophagus and gastric cardia.

OBJECTIVES: The clinical success of per-oral endoscopic myotomy (POEM) has led to the development of a new field of 'submucosal endoscopy'. This study aimed to evaluate the safety, efficacy, and limitations of per-oral endoscopic tumor resection (POET) in the management of submucosal tumors (SMTs) in the esophagus and the gastric cardia. METHODS: POET was performed in 47 patients from January 2011 to December 2017. The indication for POET was SMTs ≤ 30 mm in minor axis diameter. Patient and tumor characteristics (age, gender, tumor location, size, and histology), operative and clinical results of POET (procedure time and completion rate, en bloc resection rate, length of hospitalization, adverse events and tumor recurrence) were analyzed retrospectively. RESULTS: POET was successfully completed in 43 patients (91.5%) without any major adverse events (Clavien-Dindo IIIb-IV). Four patients required conversion to an open surgical procedure due to suboptimal visualization during POET. Four patients underwent piecemeal resection of their SMTs including GISTs. Median follow-up was 44 months (10-96 months), during that time, there were no incidences of tumor recurrence. Tumors that had a minor axis diameter > 30 mm or a tumor mass index (TMI) [major axis diameter (mm) × minor axis diameter (mm)] >1000 had a high likelihood of being converted to surgical resection. CONCLUSIONS: POET is a safe and effective treatment for SMTs. However, in patients where the minor axis diameter is > 30 mm or the TMI > 1000, surgical excision should be considered. Furthermore, application of POET for SMTs with malignant potential should be carefully considered to ensure optimal oncologic outcomes.

An Unusual Extender Unit Is Incorporated into the Modular Polyketide Synthase of Scopranones Biosynthesis.

Scopranones, produced by Streptomyces sp. BYK-11038, are the novel bone morphogenetic protein inhibitors characterized by atypical two scoop-like moieties and a 3-furanone moiety. Two scoop-like moieties connected to a 3-furanone have not previously been reported in natural products, and their biosynthesis must occur via a unique pathway. Feeding experiments using 13C-labeled precursors indicated that scopranones were synthesized from three acetates and three butyrates in polyketide-type biosynthesis. Genome mining of Streptomyces sp. BYK-11038 revealed that the candidate biosynthetic gene cluster contains 21 open reading frames (ORFs), including three modular polyketide synthases (PKSs; SprA, SprB, and SprC), which were composed of 4 modules with one loading module and 18 additional ORFs (SprD to SprU) spanning a distance of 55 kbp. The characterization of in-frame deletion mutants and feeding experiments with the predicted extender units indicated that two genes, sprP and sprR, encoding discrete 3-oxoacyl-ACP synthases, and a gene, sprO, encoding crotonyl-CoA reductase, were involved in assembling an unusual C8 branched extender unit, 2-(2-ethylbutyl)malonyl-CoA. Additionally, three ORFs, sprM, sprN, and sprT, encoding cytochrome P450s and a monooxygenase, are important tailoring enzymes in post-PKS modification. SprT is an essential enzyme for decarboxylative ring contraction via oxidation, which converts the 2-pyranone to a 3-furanone.