Nasal breathing is superior to oral breathing when performing and undergoing transnasal endoscopy: a randomized trial.

BACKGROUND : Transnasal endoscopy presents a technical difficulty when inserting the flexible endoscope. It is unclear whether a particular breathing method is useful for transnasal endoscopy. Therefore, we conducted a prospective randomized controlled trial to compare endoscopic operability and patient tolerance between patients assigned to nasal breathing or oral breathing groups. METHODS : 198 eligible patients were randomly assigned to undergo transnasal endoscopy with nasal breathing or with oral breathing. Endoscopists and patients answered questionnaires on the endoscopic operability and patient tolerance using a 100-mm visual analog scale ranging from 0 (non-existent) to 100 (most difficult/unbearable). The visibility of the upper-middle pharynx was recorded. RESULTS : Patient characteristics did not differ significantly between the groups. Nasal breathing showed a higher rate of good visibility of the upper-middle pharynx than oral breathing (91.9 % vs. 27.6 %; P < 0.001). Nasal breathing showed lower mean [SD] scores than oral breathing in terms of overall technical difficulty (21.0 [11.4] vs. 35.4 [15.0]; P < 0.001). Regarding patient tolerance, nasal breathing showed lower scores than oral breathing for overall discomfort (22.1 [18.8] vs. 30.5 [20.9]; P = 0.004) and other symptoms, including nasal and throat pain, choking, suffocating, gagging, belching, and bloating (all P < 0.05). The pharyngeal bleeding rate was lower in the nasal breathing group than in the oral breathing group (0 % vs. 9.2 %; P = 0.002). CONCLUSIONS : Nasal breathing is superior to oral breathing for those performing and undergoing transnasal endoscopy. Nasal breathing led to good visibility of the upper-middle pharynx, improved endoscopic operability, and better patient tolerance, and was safer owing to decreased pharyngeal bleeding.

Carbazochrome sodium sulfonate is not effective for prevention of post-gastric endoscopic submucosal dissection bleeding: A retrospective study.

BACKGROUND: Carbazochrome sodium sulfonate (CSS) is conventionally administered to prevent post-endoscopic submucosal dissection (ESD) bleeding in many institutions, but research on its preventive efficacy is lacking. Therefore, we investigated the risk of post-ESD bleeding and the preventive efficacy of CSS administration. METHODS: We retrospectively reviewed 304 lesions in 259 patients with gastric neoplasms who underwent ESD at Asahikawa Medical University Hospital from 2014 to 2021. In the CSS group, CSS 100 mg/day was intravenously infused with maintenance fluid replacement on postoperative days 0-2. The risk factors of post-ESD bleeding, including CSS administration, were investigated. RESULTS: The overall rate of post-ESD bleeding was 4.6% (14/304). The univariate analysis showed that atrial fibrillation (Af), warfarin intake, heparin replacement, and tumor location in the lower third were significant risk factors for increasing the likelihood of postoperative bleeding. In the multivariate analysis, Af (odds ratio [OR] 3.83, 95% CI 1.02-14.30; p < 0.05), heparin replacement (OR 4.60, 95% CI 1.02-20.70; p < 0.05), and tumor location in the lower third of the stomach (OR 6.67, 95% CI 1.43-31.00; p < 0.05) were independent factors for post-ESD bleeding. Post-ESD bleeding was observed in 5.2% (9/174) of the CSS group and 3.8% (5/130) of the non-CSS group, with no significant difference between the two groups (p = 0.783). Additionally, CSS was not shown to have preventive effects in groups with higher-risk factors, such as Af diagnosis, warfarin use, heparin replacement, and tumor location in the lower third of the stomach. CONCLUSION: CSS administration was not effective for the prevention of the post-ESD bleeding in the overall patient population as well as in higher-risk patients. This suggests that the administration of CSS for post-ESD bleeding prevention may need to be reconsidered.

Mutations Reducing In Vitro Susceptibility to Novel LpxC Inhibitors in Pseudomonas aeruginosa and Interplay of Efflux and Nonefflux Mechanisms.

Upregulated expression of efflux pumps, lpxC target mutations, LpxC protein overexpression, and mutations in fabG were previously shown to mediate single-step resistance to the LpxC inhibitor CHIR-090 in P. aeruginosa Single-step selection experiments using three recently described LpxC inhibitors (compounds 2, 3, and 4) and mutant characterization showed that these mechanisms affect susceptibility to additional novel LpxC inhibitors. Serial passaging of P. aeruginosa wild-type and efflux pump-defective strains using the LpxC inhibitor CHIR-090 or compound 1 generated substantial shifts in susceptibility and underscored the interplay of efflux and nonefflux mechanisms. Whole-genome sequencing of CHIR-090 passage mutants identified efflux pump overexpression, fabG mutations, and novel mutations in fabF1 and in PA4465 as determinants of reduced susceptibility. Two new lpxC mutations, encoding A214V and G208S, that reduce susceptibility to certain LpxC inhibitors were identified in these studies, and we show that these and other target mutations differentially affect different LpxC inhibitor scaffolds. Lastly, the combination of target alteration (LpxCA214V) and upregulated expression of LpxC was shown to be tolerated in P. aeruginosa and could mediate significant decreases in susceptibility.

Molecular Basis of mRNA Cap Recognition by Influenza B Polymerase PB2 Subunit.

Influenza virus polymerase catalyzes the transcription of viral mRNAs by a process known as "cap-snatching," where the 5'-cap of cellular pre-mRNA is recognized by the PB2 subunit and cleaved 10-13 nucleotides downstream of the cap by the endonuclease PA subunit. Although this mechanism is common to both influenza A (FluA) and influenza B (FluB) viruses, FluB PB2 recognizes a wider range of cap structures including m(7)GpppGm-, m(7)GpppG-, and GpppG-RNA, whereas FluA PB2 utilizes methylated G-capped RNA specifically. Biophysical studies with isolated PB2 cap-binding domain (PB2(cap)) confirm that FluB PB2 has expanded mRNA cap recognition capability, although the affinities toward m(7)GTP are significantly reduced when compared with FluA PB2. The x-ray co-structures of the FluB PB2(cap) with bound cap analogs m(7)GTP and GTP reveal an inverted GTP binding mode that is distinct from the cognate m(7)GTP binding mode shared between FluA and FluB PB2. These results delineate the commonalities and differences in the cap-binding site between FluA and FluB PB2 and will aid structure-guided drug design efforts to identify dual inhibitors of both FluA and FluB PB2.

Antiviral Nucleotide Incorporation by Recombinant Human Mitochondrial RNA Polymerase Is Predictive of Increased In Vivo Mitochondrial Toxicity Risk.

Nucleoside or nucleotide inhibitors are a highly successful class of antivirals due to selectivity, potency, broad coverage, and high barrier to resistance. Nucleosides are the backbone of combination treatments for HIV, hepatitis B virus, and, since the FDA approval of sofosbuvir in 2013, also for hepatitis C virus (HCV). However, many promising nucleotide inhibitors have advanced to clinical trials only to be terminated due to unexpected toxicity. Here we describe the in vitro pharmacology of compound 1, a monophosphate prodrug of a 2'-ethynyluridine developed for the treatment of HCV. Compound 1 inhibits multiple HCV genotypes in vitro (50% effective concentration [EC50], 0.05 to 0.1 µM) with a selectivity index of >300 (50% cytotoxic concentration [CC50], 30 µM in MT-4 cells). The active triphosphate metabolite of compound 1, compound 2, does not inhibit human α, ß, or γ DNA polymerases but was a substrate for incorporation by the human mitochondrial RNA polymerase (POLRMT). In dog, the oral administration of compound 1 resulted in elevated serum liver enzymes and microscopic changes in the liver. Transmission electron microscopy showed significant mitochondrial swelling and lipid accumulation in hepatocytes. Gene expression analysis revealed dose-proportional gene signature changes linked to loss of hepatic function and increased mitochondrial dysfunction. The potential of in vivo toxicity through mitochondrial polymerase incorporation by nucleoside analogs has been previously shown. This study shows that even moderate levels of nucleotide analog incorporation by POLRMT increase the risk of in vivo mitochondrial dysfunction. Based on these results, further development of compound 1 as an anti-HCV compound was terminated.

Correlation Among Body Composition Parameters and Long-Term Outcomes in Crohn's Disease After Anti-TNF Therapy.

Background: The impact of the body composition on the pathophysiology and clinical course of Crohn's disease (CD) has not been fully elucidated. Aims: To reveal the correlations among body composition and long-term outcomes in CD after anti-TNF therapy. Methods: Ninety-one patients who received anti-TNF therapy as their first biologic treatment were enrolled. The skeletal muscle index (SMI), visceral and subcutaneous fat area (VFA, SFA), and the ratio of the VFA to SFA (mesenteric fat index; MFI) at the 3rd lumbar level were measured using computed tomography (CT) imaging before the induction. The correlation among the body composition and outcomes were retrospectively analyzed. Results: The 5-year cumulative secondary failure- and resection-free rates in patients with a low SMI (39.1% and 64.8%) were significantly lower than those with a high SMI (67.5% and 92.7%; p = 0.0071 and 0.0022, respectively). The 5-year cumulative secondary failure-free rate in the patients with low VF (45.0%) was significantly lower than that in those with high VF (77.6%; p = 0.016), and the 5-year cumulative resection-free rate in patients with a high MFI (68.9%) was significantly lower than that in those with a low MFI (83.0%; p = 0.031). Additionally, patients with low age and BMI had significantly lower cumulative secondary failure- and resection-free rates than those with high age and BMI (low age: 37.4% and 71.2%; high age: 70.7% and 88.9%; p = 0.0083 and 0.027, respectively) (low BMI: 27.2% and 64.8%; high BMI: 68.3% and 87.9%; p = 0.014 and 0.030, respectively), respectively. In the multivariate analyses, a low SMI was the only independent risk factor for secondary failure (hazard ratio [HR] 2.15, 95% confidence interval [CI] 1.04-4.44), while low age (HR 4.06, 95% CI 1.07-15.4), a low SMI (HR 4.19, 95% CI 1.01-17.3) and high MFI were risk factors for bowel resection (HR 4.31, 95% CI 1.36-13.7). Conclusion: The skeletal muscle mass and ratio of visceral to subcutaneous fat were suggested to reflect the long-term clinical outcome and may be helpful as prognostic markers after anti-TNF therapy in CD.

Prognostic factors to predict the survival in patients with advanced gastric cancer who receive later-line nivolumab monotherapy-The Asahikawa Gastric Cancer Cohort Study (AGCC).

BACKGROUND: Chemotherapy for advanced gastric cancer is recommended in the guidelines; however, later-line treatment remains controversial. Since immune checkpoint inhibitors have been used for the treatment of various malignancies, trials have been performed for gastric cancer. A phase 3 trial indicated the survival benefit of nivolumab monotherapy for gastric cancer patients treated with prior chemotherapy regimens. PATIENTS AND METHODS: A regional cohort study was undertaken to determine the real-world data of nivolumab treatment for patients with advanced or recurrent gastric cancer. The patients were enrolled for 2 years from October 2017 to October 2019 and were prospectively followed for 1 year to examine the overall survival (OS). The patient characteristics were analyzed in a multivariate analysis and a nomogram to predict the probability of survival was generated. RESULTS: In total, 70 patients who received nivolumab as ≥third-line chemotherapy were included in the Asahikawa Gastric Cancer Cohort. The median OS was 7.5 (95% CI, 4.8-10.2) months and the response rate was 18.6%. Diffuse type classification, bone metastasis, high neutrophil/lymphocyte ratio, and high CRP were associated with poor OS/prognosis in the multivariate analysis. A nomogram was developed based on these clinical parameters and the concordance index was 0.80 (95% CI, 0.68-0.91). The responders were aged and were frequently diagnosed with intestinal type gastric cancer, including patients with a HER2-positive status (27.3%) or microsatellite instability-high (27.3%) status. CONCLUSIONS: The regional cohort study of nivolumab monotherapy for gastric cancer patients revealed prognostic factors and a nomogram was developed that could predict the probability of survival.

A Genome-wide CRISPR Screen Identifies ZCCHC14 as a Host Factor Required for Hepatitis B Surface Antigen Production.

A hallmark of chronic hepatitis B (CHB) virus infection is the presence of high circulating levels of non-infectious small lipid HBV surface antigen (HBsAg) vesicles. Although rare, sustained HBsAg loss is the idealized endpoint of any CHB therapy. A small molecule, RG7834, has been previously reported to inhibit HBsAg expression by targeting terminal nucleotidyltransferase proteins 4A and 4B (TENT4A and TENT4B). In this study, we describe a genome-wide CRISPR screen to identify other potential host factors required for HBsAg expression and to gain further insights into the mechanism of RG7834. We report more than 60 genes involved in regulating HBsAg and identify additional factors involved in RG7834 activity, including a zinc finger CCHC-type containing 14 (ZCCHC14) protein. We show that ZCCHC14, together with TENT4A/B, stabilizes HBsAg expression through HBV RNA tailing, providing a potential new therapeutic target to achieve functional cure in CHB patients.

Application of Virtual Screening to the Identification of New LpxC Inhibitor Chemotypes, Oxazolidinone and Isoxazoline.

This report summarizes the identification and synthesis of novel LpxC inhibitors aided by computational methods that leveraged numerous crystal structures. This effort led to the identification of oxazolidinone and isoxazoline inhibitors with potent in vitro activity against P. aeruginosa and other Gram-negative bacteria. Representative compound 13f demonstrated efficacy against P. aeruginosa in a mouse neutropenic thigh infection model. The antibacterial activity against K. pneumoniae could be potentiated by Gram-positive antibiotics rifampicin (RIF) and vancomycin (VAN) in both in vitro and in vivo models.

Fragment-Based Drug Discovery of Inhibitors of Phosphopantetheine Adenylyltransferase from Gram-Negative Bacteria.

The discovery and development of new antibiotics capable of curing infections due to multidrug-resistant and pandrug-resistant Gram-negative bacteria are a major challenge with fundamental importance to our global healthcare system. Part of our broad program at Novartis to address this urgent, unmet need includes the search for new agents that inhibit novel bacterial targets. Here we report the discovery and hit-to-lead optimization of new inhibitors of phosphopantetheine adenylyltransferase (PPAT) from Gram-negative bacteria. Utilizing a fragment-based screening approach, we discovered a number of unique scaffolds capable of interacting with the pantetheine site of E. coli PPAT and inhibiting enzymatic activity, including triazolopyrimidinone 6. Structure-based optimization resulted in the identification of two lead compounds as selective, small molecule inhibitors of bacterial PPAT: triazolopyrimidinone 53 and azabenzimidazole 54 efficiently inhibited E. coli and P. aeruginosa PPAT and displayed modest cellular potency against the efflux-deficient E. coli Δ tolC mutant strain.

Discovery and Optimization of Phosphopantetheine Adenylyltransferase Inhibitors with Gram-Negative Antibacterial Activity.

In the preceding manuscript [ Moreau et al. 2018 , 10.1021/acs.jmedchem.7b01691 ] we described a successful fragment-based lead discovery (FBLD) strategy for discovery of bacterial phosphopantetheine adenylyltransferase inhibitors (PPAT, CoaD). Following several rounds of optimization two promising lead compounds were identified: triazolopyrimidinone 3 and 4-azabenzimidazole 4. Here we disclose our efforts to further optimize these two leads for on-target potency and Gram-negative cellular activity. Enabled by a robust X-ray crystallography system, our structure-based inhibitor design approach delivered compounds with biochemical potencies 4-5 orders of magnitude greater than their respective fragment starting points. Additional optimization was guided by observations on bacterial permeability and physicochemical properties, which ultimately led to the identification of PPAT inhibitors with cellular activity against wild-type E. coli.

Structural basis for therapeutic inhibition of influenza A polymerase PB2 subunit.

Influenza virus uses a unique mechanism to initiate viral transcription named cap-snatching. The PB2 subunit of the viral heterotrimeric RNA polymerase binds the cap structure of cellular pre-mRNA to promote its cleavage by the PA subunit. The resulting 11-13 capped oligomer is used by the PB1 polymerase subunit to initiate transcription of viral proteins. VX-787 is an inhibitor of the influenza A virus pre-mRNA cap-binding protein PB2. This clinical stage compound was shown to bind the minimal cap-binding domain of PB2 to inhibit the cap-snatching machinery. However, the binding of this molecule in the context of an extended form of the PB2 subunit has remained elusive. Here we generated a collection of PB2 truncations to identify a PB2 protein representative of its structure in the viral heterotrimeric protein. We present the crystal structure of VX-787 bound to a PB2 construct that recapitulates VX-787's biological antiviral activity in vitro. This co-structure reveals more extensive interactions than previously identified and provides insight into the observed resistance profile, affinity, binding kinetics, and conformational rearrangements induced by VX-787.