Glomerular Endothelial Cell Receptor ADGRF5 and the Integrity of the Glomerular Filtration Barrier.

BACKGROUND: Glomerular endothelial cells are recognized to be important for maintaining the glomerular filtration barrier. ADGRF5, an adhesion G protein-coupled receptor, has been suggested to be involved in endothelial cell function. However, the role of ADGRF5 in the glomerular filtration barrier integrity remains elusive. METHODS: Cellular expression of ADGRF5 in mouse glomerulus was determined by histological analyses. The impact of ADGRF5 deletion on the glomerular morphology, kidney function, and glomerular endothelial gene/protein expression was then analyzed using ADGRF5 knockout (Adgrf5-/-) mice and human primary glomerular endothelial cells. RESULTS: ADGRF5 was specifically expressed in the capillary endothelial cells within the glomerulus. Adgrf5-/- mice developed albuminuria and impaired kidney function with morphological defects in the glomeruli, namely glomerular hypertrophy, glomerular basement membrane splitting and thickening, diaphragmed fenestration and detachment of the glomerular endothelial cells, and mesangial interposition. These defects were accompanied by the altered expression of genes responsible for glomerular basement membrane organization (type IV collagens and laminins) and Krüppel-like factor 2 (Klf2) in glomerular endothelial cells. Moreover, ADGRF5 knockdown decreased COL4A3 and COL4A4 expression and increased KLF2 expression in human primary glomerular endothelial cells. CONCLUSIONS: The loss of ADGRF5 resulted in altered gene expression in glomerular endothelial cells, and perturbed the structure and permselectivity of the glomerular filtration barrier.

Clinical outcomes of anti-reflux mucosal ablation for gastroesophageal reflux disease: An international bi-institutional study.

BACKGROUND AND AIM: Anti-reflux mucosal ablation (ARMA) is an emerging endoscopic treatment aimed at enhancing the gastroesophageal junction flap valve. This study aimed to evaluate its feasibility, effectiveness, and safety. METHODS: Between May 2018 and December 2022, patients with gastroesophageal reflux disease (GERD) symptoms refractory to acid suppression medications or those dependent on such medications were enrolled for ARMA. This retrospective analysis utilized prospectively collected data from an international bi-center study. GERD questionnaire, upper endoscopy, and 24-h pH monitoring were conducted at 2-6 months and 12 months post-ARMA. Clinical success was defined as a > 50% reduction in a validated GERD questionnaire. RESULTS: A total of 68 patients underwent ARMA. Definitive GERD was diagnosed in 44 (64.7%) patients, while 24 (35.3%) exhibited reflux hypersensitivity. Clinical success rates at 2-6 months and 1 year post-ARMA were 60% (39/65) and 70% (21/30), respectively. The median GERD-health-related quality of life score significantly improved from 26 to 11 at 2-6 months (P < 0.001). Among the 51 patients (71.8%) who underwent 24-h pH monitoring, the median acid exposure time decreased from 5.3% to 0.7% (P = 0.003), accompanied by a significant reduction in esophagitis rates (P < 0.001). Multivariate analysis did not identify predictors of short-term success. Nine (13.2%) patients experienced transient stenosis requiring balloon dilation. CONCLUSIONS: ARMA demonstrates both technical feasibility and reproducibility as a safe procedure that effectively ameliorates GERD symptoms in approximately two-thirds of patients during short-term follow up. Both reflux hypersensitivity and confirmed GERD patients, regardless of their response to acid suppression medication, may be suitable candidates.

Concise Synthesis of 11-Noriridoids via Pauson-Khand Reaction.

Iridoids, which are a class of monoterpenoids, are attractive synthetic targets due to their diversely substituted cis-fused cyclopenta[c]pyran skeletons. Additionally, various biological activities of iridoids raise the value of synthetic studies on this class of compounds. Here, our synthetic efforts toward 11-noriridoids; (±)-umbellatolide B (6), (±)-10-O-benzoylglobularigenin (9) and 1-O-pentenylaucubigenin (34) are described. For the efficient synthesis of target compounds, common synthetic intermediates (tricyclic enones 17 and 26) were prepared by the Pauson-Khand reaction. The cleavage of the acetal bond on the tricyclic enones and 1,2-reduction introduced the two hydroxy groups on the cyclopentane ring of the core scaffold. Furthermore, the C3-C4 olefin part was constructed by the syn-elimination of a thiocarbonate moiety to obtain 34. The developed synthetic routes for 6, 9, and 34 will be useful for the preparation of iridoid analogs that have a polyfunctionalized core skeleton.

Advancements in minimally invasive endoscopic treatment: Navigating deeper layers for upper gastrointestinal lesion.

The field of minimally invasive endoscopic treatment has seen a continual progression, marked by significant advancements in treatment devices and the refinement of endoscopic techniques. While endoscopic resection has become the standard for treating superficial gastrointestinal neoplasms, a proactive approach becomes imperative when dealing with lesions that extend beyond the submucosal layer and deeper into the muscularis propria. The ongoing evolution of endoscopic closure techniques has facilitated the introduction of advanced procedures such as endoscopic muscularis dissection, endoscopic subserosal dissection, and endoscopic full-thickness resection. This evolution is achieved by the commitment to improve the efficacy and precision in treating challenging lesions. Nevertheless, there is currently a lack of definitive guidelines or consensus regarding the specifics of deeper layer dissection. Drawing from prior research and clinical insights, this review discusses indications, techniques, clinical outcomes, and future perspectives of deeper layer dissection.

Endoscopic pressure study integrated system using an ultrathin gastroscope for the functional assessment of the lower esophageal sphincter.

OBJECTIVES: The endoscopic pressure study integrated system (EPSIS) represents an innovative approach for evaluating lower esophageal sphincter function by monitoring intragastric pressure using diagnostic gastroscopes. This study aimed to assess the feasibility and validity of employing ultrathin gastroscopes for EPSIS. METHODS: A retrospective analysis was conducted on a database of consecutive patients who underwent EPSIS using both ultrathin and regular gastroscopes between September 2021 and October 2023. The study compared EPSIS parameters between the two gastroscope types to evaluate the correlation of key metrics. RESULTS: Thirty patients underwent EPSIS with both ultrathin and regular gastroscopes. Significant positive correlations were observed in the pressure waveform: maximum intragastric pressure (mmHg) (ρ = 0.82, P < 0.001) and intragastric pressure gradient (mmHg/s) (ρ = 0.80, P < 0.001) when comparing the two gastroscopes. Maximum intragastric pressure (15.5 [5.3-20.3] vs. 18.5 [3.4-21.6], P < 0.001) and pressure gradient (0.16 [0.013-0.41] vs. 0.24 [0.0039-1.13], P < 0.001), (median [range]) were significantly lower with ultrathin gastroscopes. CONCLUSIONS: This study establishes that EPSIS parameters obtained with an ultrathin gastroscope exhibit a significant correlation with those obtained using a regular gastroscope, with each EPSIS parameter consistently lower. These findings support the viability of EPSIS for ultrathin gastroscopy and highlight its potential as a diagnostic tool for assessing lower esophageal sphincter function.

Hood attached vs conventional triangular tip-jet knife in peroral endoscopic myotomy: a propensity score matching cohort study.

BACKGROUND & AIM: Peroral endoscopic myotomy (POEM) is a safe and effective endoscopic treatment for achalasia and other esophageal motility disorders, and TTJ (Triangle Tip Knife J; Olympus, Tokyo, Japan) is currently widely used in POEM. Recently, we reported a novel modification of TTJ, which was adjusted to knife length 2 mm by attaching a disposable clip (QuickClip Pro; Olympus) sheath to the tip as a hood attachment. In this study, we compared the safety and effectiveness of TTJ and TTJ with hood attachment (TTJ-H) in POEM. METHODS: In this 1:1 propensity score matched retrospective cohort study, we compared the procedure time, myotomy efficiency, number of coagulation forceps usage, adverse events, length of hospital stay after POEM, procedural success and clinical success between TTJ and TTJ-H groups. RESULTS: We examined 682 consecutive patients who underwent POEM between January 2021 and June 2023. We excluded 134 patients who had already undergone POEM or laparoscopic Heller myotomy as prior myotomy. Finally, we identified 98 propensity score-matched pairs (n = 196). The mean procedure time was shortened from 93.5 to 80.2 min (14% reduction, P = 0.012) when comparing TTJ-H group to TTJ group. The mean myotomy efficiency was improved from 2.76 to 2.32 min/cm (16% improvement, P = <0.001), and usage of coagulation forceps for hemostasis was decreased from 3.87 to 0.55 (86% reduction, P = <0.001). CONCLUSIONS: This study showed that use of TTJ-H could reduce total procedure time, improve myotomy efficiency, and reduce costs compared to TTJ.

Timing of colonoscopy in acute lower GI bleeding: a multicenter retrospective cohort study.

BACKGROUND AND AIMS: We aimed to determine the optimal timing of colonoscopy and factors that benefit patients who undergo early colonoscopy for acute lower GI bleeding. METHODS: We identified 10,342 patients with acute hematochezia (CODE BLUE-J study) admitted to 49 hospitals in Japan. Of these, 6270 patients who underwent a colonoscopy within 120 hours were included in this study. The inverse probability of treatment weighting method was used to adjust for baseline characteristics among early (≤24 hours, n = 4133), elective (24-48 hours, n = 1137), and late (48-120 hours, n = 1000) colonoscopy. The average treatment effect was evaluated for outcomes. The primary outcome was 30-day rebleeding rate. RESULTS: The early group had a significantly higher rate of stigmata of recent hemorrhage (SRH) identification and a shorter length of stay than the elective and late groups. However, the 30-day rebleeding rate was significantly higher in the early group than in the elective and late groups. Interventional radiology (IVR) or surgery requirement and 30-day mortality did not significantly differ among groups. The interaction with heterogeneity of effects was observed between early and late colonoscopy and shock index (shock index <1, odds ratio [OR], 2.097; shock index ≥1, OR, 1.095; P for interaction = .038) and performance status (0-2, OR, 2.481; ≥3, OR, .458; P for interaction = .022) for 30-day rebleeding. Early colonoscopy had a significantly lower IVR or surgery requirement in the shock index ≥1 cohort (OR, .267; 95% confidence interval, .099-.721) compared with late colonoscopy. CONCLUSIONS: Early colonoscopy increased the rate of SRH identification and shortened the length of stay but involved an increased risk of rebleeding and did not improve mortality and IVR or surgery requirement. Early colonoscopy particularly benefited patients with a shock index ≥1 or performance status ≥3 at presentation.

In Situ and Ex Situ Studies of Ring-Like Assembly of Silica Nanoparticles in the Presence of Poly(propylene oxide)-Poly(ethylene oxide) Block Copolymers.

Block copolymer-mediated self-assembly of colloidal nanoparticles has attracted great attention for fabricating various nanoparticle arrays. We have previously shown that silica nanoparticles (SNPs) assemble into ring-like nanostructures in the presence of temperature-responsive block copolymers poly[(2-ethoxyethyl vinyl ether)-block-(2-methoxyethyl vinyl ether)] (PEOVE-PMOVE) in an aqueous phase. The ring-like nanostructures formed within an aggregate of PEOVE-PMOVE when the temperature was increased to 45 °C, at which the polymer is amphiphilic. Herein, we report that SNPs assemble into ring-like nanostructures even with a different temperature-responsive, amphiphilic block copolymer poly(propylene oxide)-block-poly(ethylene oxide) (PPO-PEO) at 45 °C. Field-emission scanning electron microscopy for SNP assemblies that were spin-coated on a substrate indicated that SNP first assembled into chain-like nanostructures and then bent into closed loops over several days. In contrast, in situ small-angle X-ray diffraction measurements revealed the formation of SNP nanorings within 75 s at 45 °C in the liquid phase. These results indicated that ring-like assembly of SNPs occurs quickly in the liquid phase, but the slow formation of Si-O-Si bonds between SNPs leads to their structure being destroyed by spin-coating. Intriguingly, SNPs with a diameter of 15 nm form a well-defined nanoring structure, with five SNPs located at the vertex points of a regular pentagon. Additionally, small-angle neutron scattering, where the contrast of the solvent (a mixture of H2O and D2O) matches that of SNPs, clarified that SNPs are contained within the spherical micelle formed from PPO-PEO. This work offers a facile and versatile approach to preparing ring-like arrays from inorganic colloidal nanoparticles, leading to applications including sensing, catalysis, and nanoelectronics.

Expansion of Phosphoramidite Chemistry in Solid-Phase Oligonucleotide Synthesis: Rapid 3'-Dephosphorylation and Strand Cleavage.

In solid-phase oligonucleotide synthesis, a solid support modified with a universal linker is frequently used to prepare oligonucleotides bearing non-natural- or non-nucleosides at the 3'-end. Generally, harsh basic conditions such as hot aqueous ammonia or methylamine are required to release oligonucleotides by 3'-dephosphorylation via the formation of cyclic phosphate with the universal linker. To achieve 3'-dephosphorylation under milder conditions, we used O-alkyl phosphoramidites instead of the commonly used O-cyanoethyl phosphoramidites at the 3'-end of oligonucleotides. Alkylated phosphotriesters are more alkali-tolerant than their cyanoethyl counterparts because the latter generates phosphodiesters via E2 elimination under basic conditions. Among the designed phosphoramidites, alkyl-extended analogs exhibited rapid and efficient 3'-dephosphorylation compared to conventional cyanoethyl and methyl analogs under mild basic conditions such as aqueous ammonia at room temperature for 2 h. Moreover, nucleoside phosphoramidites bearing 1,2-diols were synthesized and incorporated into oligonucleotides. 1,2,3,4-Tetrahydro-1,4-epoxynaphthalene-2,3-diol-bearing phosphoramidite behaved like a universal linker at the 3'-terminus, allowing dephosphorylation and strand cleavage of the oligonucleotide chain to occur efficiently. Our strategy using this new phosphoramidite chemistry is promising for the tandem solid-phase synthesis of diverse oligonucleotides.

Solid-Phase Synthesis of Nannocystin Ax and Its Analogues.

Solid-phase total synthesis of nannocystin Ax (1) was disclosed. A coupling reaction between a peptide and a polyketide moiety was conducted on a solid support, and macrocyclization was achieved by Mitsunobu cyclization. The established synthetic route was efficient to prepare its analogues, which contain different types of peptide moieties.

Utility of Under-Gel Endoscopic Mucosal Resection with Partial Submucosal Injection and Under-Gel Precutting Endoscopic Mucosal Resection for Difficult Colorectal Polyp Cases.

BACKGROUND: Here, we evaluated the utility of under-gel endoscopic mucosal resection (EMR) with partial submucosal injection (PI) and under-gel precutting EMR for difficult-to-treat colorectal polyps. METHODS: A retrospective case series was conducted from April 1, 2020, to April 1, 2021, at St. Luke's International Hospital (Japan). We included all consecutive patients who underwent colonoscopy and subsequent under-gel EMR with PI and under-gel precutting EMR. Baseline and clinical data were obtained from electronic medical records. RESULTS: Under-gel EMR with PI was performed in 6 patients, treating a total of seven lesions. In this group, 50% (3/6) were women (mean age = 59.2 years). The mean procedure time and specimen size were 5.1 min and 12.1 mm, respectively, achieving a 100% (7/7) en bloc resection rate. Under-gel precutting EMR was performed in 8 patients. In this group, 50% (4/8) were women (mean age = 66.1 years). The mean procedure time and specimen size were 22.6 min and 23.0 mm, respectively; en bloc resection rate was 62.5% (5/8). Regarding lesions over 20 mm in diameter, the en bloc resection rate was 50% (3/6). No complications were observed. CONCLUSIONS: PI is potentially useful for colorectal polyps where the distal end is not visible; when PI cannot be used, precutting EMR may constitute another troubleshooting method for difficult-to-treat colorectal polyps. The gel immersion method is also a viable option when the use of water causes rapid mixing of blood and residual stool, resulting in poor visibility.

Chi-square automatic interaction detector decision tree analysis model: Predicting cefmetazole response in intra-abdominal infection.

BACKGROUND: Cefmetazole is used as the first-line treatment for intra-abdominal infections. However, only a few studies have investigated the risk factors for cefmetazole treatment failure. AIMS: This study aimed to develop a decision tree-based predictive model to assess the effectiveness of cefmetazole in initial intra-abdominal infection treatment to improve the clinical treatment strategies. METHODS: This retrospective cohort study included adult patients who were unexpectedly hospitalized due to intra-abdominal infections between 2003 and 2020 and initially treated with cefmetazole. The primary outcome was clinical intra-abdominal infection improvement. The chi-square automatic interaction detector decision tree analysis was used to create a predictive model for clinical improvement after cefmetazole treatment. RESULTS: Among 2,194 patients, 1,807 (82.4%) showed clinical improvement post-treatment; their mean age was 48.7 (standard deviation: 18.8) years, and 1,213 (55.3%) patients were men. The intra-abdomせinal infections were appendicitis (n = 1,186, 54.1%), diverticulitis (n = 334, 15.2%), and pancreatitis (n = 285, 13.0%). The chi-square automatic interaction detector decision tree analysis identified the intra-abdominal infection type, C-reactive protein level, heart rate, and body temperature as predictive factors by categorizing patients into seven groups. The area under the receiver operating characteristic curve was 0.71 (95% confidence interval: 0.68-0.73). CONCLUSION: This predictive model is easily understandable visually and may be applied in clinical practice.

Feasibility and safety of per-oral endoscopic septotomy for Killian-Jamieson diverticulum: Case series with video.

BACKGROUND AND AIMS: Killian-Jamieson diverticulum (KJD) is a relatively uncommon variant of pharyngoesophageal diverticula, distinct from the more prevalent Zenker diverticulum. However, literature on endoscopic management of KJD remains limited. This study aimed to elucidate the efficacy and safety of peroral endoscopic septotomy (POES) as a treatment approach for symptomatic KJD. METHODS: In this retrospective observational study, we investigated the outcomes of nine consecutive patients who underwent POES for KJD between January 2019 and May 2023. Follow-up data of at least 2 months post-treatment were analyzed. The primary outcome measure was the technical success rate of POES. Secondary outcomes encompassed the clinical success rate, defined as symptomatic improvement 2 months after POES, and the incidence of adverse events. RESULTS: All patients presented with dysphagia, with a median symptom duration of 6 months (interquartile range [IQR]: 3-12 months). The median diverticulum size was 32 mm (IQR: 24-42 mm). The median duration of the operation time was 66 min (IQR: 60-109). A 100% technical success rate was achieved, with complete closure of the defect in all cases. There were no adverse events related to this treatment. The median hospitalization duration was 5 days (IQR: 4-6), and the clinical success rate was 88.9%. Follow-up barium esophagograms exhibited significant improvement in the flow of the barium for all patients. CONCLUSIONS: Despite the relatively limited case volume, our findings underscore that POES is a safe and efficacious approach for managing symptomatic KJD.

Pilot study on anti-reflux mucoplasty: Advancing endoscopic anti-reflux therapy for gastroesophageal reflux disease.

OBJECTIVES: Anti-reflux mucosectomy (ARMS) and anti-reflux mucosal ablation (ARMA) were developed as interventions for proton pump inhibitor (PPI)-refractory/-dependent gastroesophageal reflux disease (GERD). Although ARMS and ARMA are established treatments for PPI-refractory GERD, reliance on natural healing for ulcer scar formation introduces uncertainty and bleeding risk. To address these issues, we introduced a novel approach called anti-reflux mucoplasty (ARM-P), which involves immediate closure of mucosal defects following mucosectomy. This pilot study aims to evaluate the safety, feasibility, and efficacy of ARM-P. METHODS: A retrospective single-center study was conducted using prospectively collected data from October 2022 to July 2023. Patients with PPI-refractory/-dependent GERD who underwent ARM-P were included. The study evaluated technical success of ARM-P, before and after ARM-P GERD-Health Related Quality of Life Questionnaire, GerdQ, and Frequency Scale for the Symptoms of GERD scores, along with PPI discontinuation and endoscopic esophagogastric junction morphology. RESULTS: A total of 20 patients with a median age of 61.5 years underwent the ARM-P procedure. The procedure achieved 100% technical success without adverse events. After ARM-P, 55.0% discontinued PPI usage and 15.0% reduced PPI dose by half. Median GERD-Health Related Quality of Life Questionnaire score improved from 21 to 6 (P = 0.0026), median GerdQ score improved from 9 to 7 (P = 0.0022), and median Frequency Scale for the Symptoms of GERD score decreased from 16 to 7 (P = 0.0003). Median Hill's Classification significantly improved from grade III to grade I (P = 0.0001). CONCLUSIONS: This study presents the first pilot report of ARM-P, demonstrating its procedural safety, technical feasibility, and short-term efficacy.

Endoscopic pressure study integrated system for the diagnosis of achalasia.

OBJECTIVES: The endoscopic pressure study integrated system (EPSIS) is a novel diagnostic tool used to evaluate lower esophageal sphincter (LES) function. EPSIS allows the measurement of intragastric pressure (IGP) during gastric insufflation through esophagogastroduodenoscopy (EGD) and records its pressure waveform. This study aimed to assess the usefulness and applicability of EPSIS as an adjunct diagnostic modality for achalasia. METHODS: This case-control study was conducted using a database of patients who underwent EGD, barium swallow (BS), high-resolution manometry (HRM), and EPSIS between January 2022 and December 2022. The achalasia (experimental) group (n = 35) consisted of patients with a definitive diagnosis of achalasia. The control group (n = 34) consisted of patients with no abnormalities in EGD, BS, or HRM and no abnormal acid reflux confirmed with 24-h pH-impedance monitoring. EPSIS findings were compared between the two groups and characterized by the waveform pattern (uphill or flat), maximum IGP (IGP-Max), pressure difference, and the gradient of the waveform. RESULTS: All patients in the achalasia group showed an uphill pattern, in contrast to 21 patients (61.8%) in the control group. IGP-Max demonstrated the best diagnostic accuracy for achalasia, with a cut-off value of 15.8 mmHg (100% sensitivity, 58.8% specificity, and area under the curve [AUC] 0.78). The pressure gradient also demonstrated good diagnostic accuracy, with a cut-off value of 0.40 mmHg/s (80% sensitivity, 61.8% specificity, and AUC 0.76). CONCLUSION: This study demonstrated that EPSIS can be applied as a diagnostic modality in patients with achalasia.

Dephospho-Coenzyme A Kinase Is an Exploitable Drug Target against Plasmodium falciparum: Identification of Selective Inhibitors by High-Throughput Screening of a Large Chemical Compound Library.

Malaria is a mosquito-borne fatal infectious disease that affects humans and is caused by Plasmodium parasites, primarily Plasmodium falciparum. Widespread drug resistance compels us to discover novel compounds and alternative drug discovery targets. The coenzyme A (CoA) biosynthesis pathway is essential for the malaria parasite P. falciparum. The last enzyme in CoA biosynthesis, dephospho-CoA kinase (DPCK), is essential to the major life cycle development stages but has not yet been exploited as a drug target in antimalarial drug discovery. We performed a high-throughput screen of a 210,000-compound library using recombinant P. falciparum DPCK (PfDPCK). A high-throughput enzymatic assay using a 1,536-well platform was developed to identify potential PfDPCK inhibitors. PfDPCK inhibitors also inhibited parasite growth in a P. falciparum whole-cell asexual blood-stage assay in both drug-sensitive and drug-resistant strains. Hit compounds were selected based on their potency in cell-free (PfDPCK) and whole-cell (Pf3D7 and PfDd2) assays, selectivity over the human orthologue (HsCOASY) and no cytotoxicity (HepG2). The compounds were ranked using a multiparameter optimization (MPO) scoring model, and the specific binding and the mechanism of inhibition were investigated for the most promising compounds.

Screening of anti-atrophic peptides by using photo-cleavable peptide array and 96-well scale contractile human skeletal muscle atrophy models.

Skeletal muscle atrophy is characterized by decreases in protein content, myofiber diameter, and contractile force generation. As muscle atrophy worsens the quality of life, the development of anti-atrophic substances is desirable. In this study, we aimed to demonstrate a screening process for anti-atrophic peptides using photo-cleavable peptide array technology and human contractile atrophic muscle models. We developed a 96-well system and established a screening process with less variability. Dexamethasone-induced human atrophic tissue was constructed in the system. Eight peptides were selected from the literature and used for the screening of peptides for preventing the decrease of the contractile forces of tissues. The peptide QIGFIW, which showed preventive activity, was selected as the seed sequence. As a result of amino acid substitution, we obtained QIGFIQ as a peptide with higher anti-atrophic activity. These results indicate that the combinatorial use of the photo-cleavable peptide array technology and 96-well screening system could comprise a powerful approach to obtaining anti-atrophic peptides, and suggest that the 96-well screening system and atrophic model represent a practical and powerful tool for the development of drugs/functional food ingredients.

Screening for Inhibitors of Main Protease in SARS-CoV-2: In Silico and In Vitro Approach Avoiding Peptidyl Secondary Amides.

In addition to vaccines, antiviral drugs are essential for suppressing COVID-19. Although several inhibitor candidates were reported for SARS-CoV-2 main protease, most are highly polar peptidomimetics with poor oral bioavailability and cell membrane permeability. Here, we conducted structure-based virtual screening and in vitro assays to obtain hit compounds belonging to a new chemical space, excluding peptidyl secondary amides. In total, 180 compounds were subjected to the primary assay at 20 µM, and nine compounds with inhibition rates of >5% were obtained. The IC50 of six compounds was determined in dose-response experiments, with the values on the order of 10-4 M. Although nitro groups were enriched in the substructure of the hit compounds, they did not significantly contribute to the binding interaction in the predicted docking poses. Physicochemical properties prediction showed good oral absorption. These new scaffolds are promising candidates for future optimization.

Biliary balloon dilator impaction in a non-dilated bile duct with anatomical variations: a case report.

BACKGROUND: While techniques for extracting large stones from dilated bile ducts are increasing, options for small stones impacted in non-dilated bile ducts are limited. CASE PRESENTATION: We report the case of an impacted biliary balloon dilator in a choledocholithiasis patient with a non-dilated bile duct and multiple anatomical variations, including low insertion of the cystic duct. After unsuccessful attempts with a stone extraction basket and balloon, a biliary balloon dilator with a sharp catheter tip was advanced into the bile duct. The balloon could not be removed from the bile duct even when deflated. The duodenoscope fell back into the stomach, causing the shaft of the dilator to break near the ampulla. We then removed the broken tip with a snare, which caused the balloon sheath to separate from the shaft and remain in the bile duct. Finally, we removed the sheath with rat-tooth forceps, leading to successful extraction of the stone-and-balloon complex. CONCLUSIONS: The exceedingly rare possibility of balloon impaction should be kept in mind when using biliary balloon dilators in non-dilated bile ducts.

Design, synthesis and conformation-activity relationship analysis of LNA/BNA-type 5'-O-aminoribosyluridine as MraY inhibitors.

It is important to understand and control the biologically active conformation in medicinal chemistry. Muraymycins and caprazamycins, which are strong inhibitors of MraY, are promising antibacterial agents with a novel mode of action. Focusing on a sugar puckering and a dihedral angle ϕ of the uridine moiety of these natural products, LNA/BNA-type 5'-O-aminoribosyluridine analogues, whose puckering of the ribose moiety are completely restricted to the N-type, were designed and synthesized as simplified MraY inhibitors. Their conformation-activity relationship was further investigated in details. The conformation-activity relationship analysis investigated in this study could be a general guideline for simplification and rational drug design of MraY inhibitory nucleoside natural products.