Inhibitory effects of senkyuchachosan on SARS-CoV-2 papain-like protease activity in vitro.

Papain-like protease (PLpro) enzyme plays a vital role in viral replication as it breaks down polyproteins and disrupts the host's immune response. There are few reports on Kampo formulas that focus on PLpro activity. In this study, we evaluated the inhibitory effects of senkyuchachosan, a traditional Japanese medicine, on PLpro of SARS-CoV-2, the virus responsible for causing COVID-19. We purified the PLpro enzyme and conducted in vitro enzymatic assays using specific substrates. Among the nine crude drugs present in senkyuchachosan, four (Cyperi Rhizoma, Schizonepetae Spica, Menthae Herba, and Camelliae sinensis Folium [CsF]) strongly inhibited PLpro activity. CsF, derived from Camellia sinensis (green tea), contains polyphenols, including catechins and tannins. To confirm that the PLpro inhibitory effects of senkyuchachosan predominantly stem from tannins, the tannins were removed from the decoction using polyvinylpolypyrrolidone (PVPP). The inhibitory effect of senkyuchachosan on PLpro activity was reduced by the removal of PVPP. In addition, the tannin fraction obtained from the CsF extracts showed significant PLpro inhibitory effects. These findings lay the groundwork for the potential development of therapeutic agents that target SARS-CoV-2 infection by intervening in proteolytic cleavage of the virus.

Human norovirus cultivation systems and their use in antiviral research.

Human norovirus (HuNoV) is a major cause of acute gastroenteritis and foodborne diseases, affecting all age groups. Despite its clinical needs, no approved antiviral therapies are available. Since the discovery of HuNoV in 1972, studies on anti-norovirals, mechanism of HuNoV infection, viral inactivation, etc., have been hampered by the lack of a robust laboratory-based cultivation system for HuNoV. A recent breakthrough in the development of HuNoV cultivation systems has opened opportunities for researchers to investigate HuNoV biology in the context of de novo HuNoV infections. A tissue stem cell-derived human intestinal organoid/enteroid (HIO) culture system is one of those that supports HuNoV replication reproducibly and, to our knowledge, is most widely distributed to laboratories worldwide to study HuNoV and develop therapeutic strategies. This review summarizes recently developed HuNoV cultivation systems, including HIO, and their use in antiviral studies.

Reconsidering resectable oncological conditions in pancreatic tail cancer: A multicenter retrospective study on prognostic factors in pancreatic tail cancer after resection (HOPS Pt-01).

BACKGROUND: Pancreatic tail cancer (Pt-PC) is generally considered resectable when metastasis is absent, but doubts persist in clinical practice due to the variability in local tumor extent. We conducted a multicenter retrospective study to comprehensively identify prognostic factors associated with Pt-PC after resection. METHODS: We enrolled 100 patients that underwent distal pancreatectomy. The optimal combination of factors influencing relapse-free survival (RFS) was determined using the maximum likelihood method (MLM) and corrected Akaike and Bayesian information criteria (AICc and BIC). Prognostic elements were then validated to predict oncological outcomes. RESULTS: Therapeutic interventions included neoadjuvant treatment in 16 patients and concomitant visceral resection (CVR) in 37 patients; 89 patients achieved R0. Median RFS and OS after surgery were 23.1 and 37.1 months, respectively. AICc/BIC were minimized in the model with ASA-PS (≥2), CA19-9 (≥112 U/mL at baseline, non-normalized postoperatively), need for CVR, 6 pathological items (tumor diameter ≥19.5 mm, histology G1, invasion of the anterior pancreatic border, splenic vein invasion, splenic artery invasion, lymph node metastasis), and completed adjuvant treatment (cAT) for RFS. Regarding the predictive value of these 11 factors, area under the curve was 0.842 for 5-year RFS. Multivariate analysis of these 11 factors showed that predictors of RFS include CVR (hazard ratio, 2.13; 95 % confidence interval, 1.08-4.19; p = 0.028) and cAT (0.38, 0.19-0.76; p = 0.006). CONCLUSIONS: The MLM identified certain Pt-PC cases warranting consideration beyond resectable during clinical management. Particular attention should be paid to conditions requiring CVR, even though immortal time bias remains unresolved with adjuvant treatment.

Inhibition of furin-like enzymatic activities and SARS-CoV-2 infection by osthole and phenolic compounds with aryl side chains.

Coronavirus disease 2019 (COVID-19), caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), spread as a pandemic and caused damage to people's lives and countries' economies. The spike (S) protein of SARS-CoV-2 contains a cleavage motif, Arg-X-X-Arg, for furin and furin-like enzymes at the boundary of the S1/S2 subunits. Given that cleavage plays a crucial role in S protein activation and viral entry, the cleavage motif was selected as the target. Our previous fluorogenic substrate study showed that osthole, a coumarin compound, inhibits furin-like enzyme activity. In this study, we examined the potential activities of 15 compounds with a structure-activity relationship with osthole, and evaluated their protective ability against SARS-CoV-2 infection. Of the 15 compounds tested, compounds C1 and C2 exhibited the inhibitory effects of osthole against furin-like enzymatic activity; however, little or no inhibitory effects against furin activity were observed. We further examined the inhibition of SARS-CoV-2 activity by compounds C1 and C2 using a Vero E6 cell line that expresses the transmembrane protease serine 2 (TMPRSS2). Compounds C1, C2, and osthole effectively inhibited SARS-CoV-2 infection. Therefore, osthole and its derivatives can potentially be used as therapeutic agents against SARS-CoV-2.

Electrolyzed hypochlorous acid water exhibits potent disinfectant activity against various viruses through irreversible protein aggregation.

It is essential to employ efficient measures to prevent the transmission of pathogenic agents during a pandemic. One such method involves using hypochlorous acid (HClO) solution. The oxidative properties of HClO water (HAW) can contribute to its ability to eliminate viral particles. Here, we examined a highly purified slightly acidic hypochlorous acid water (Hp-SA-HAW) obtained from the reverse osmosis membrane treatment of an electrolytically-generated SA-HAW for its anti-viral activity and mode of action on viral proteins. Hp-SA-HAW exhibited broad-spectrum antiviral effects against various viruses, including adenovirus, hepatitis B virus, Japanese encephalitis virus (JEV), and rotavirus. Additionally, Hp-SA-HAW treatment dose-dependently resulted in irreversibly aggregated multimers of the JEV envelope and capsid proteins. However, Hp-SA-HAW treatment had no discernible effect on viral RNA, indicating that Hp-SA-HAW acts against amino acids rather than nucleic acids. Furthermore, Hp-SA-HAW substantially reduced the infectivity of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), including the ancestral variant and other multiple variants. Hp-SA-HAW treatment induced the aggregation of the SARS-CoV-2 spike and nuclear proteins and disrupted the binding of the purified spike protein of SARS-CoV-2 to human ACE2. This study demonstrates that the broad-spectrum virucidal activity of highly purified HClO is attributed to viral protein aggregation of virion via protein oxidation.

Risk factors for early and late cholecystitis after covered metal stent placement for distal biliary obstruction.

BACKGROUND: Cholecystitis is a major adverse event after self-expandable metallic stent placement for distal biliary obstruction (DBO). Covered self-expandable metallic stent (CSEMS) is being increasingly used, but few studies have investigated risk factors for cholecystitis limited to CSEMS. The present study aimed to identify risk factors for cholecystitis after CSEMS. METHODS: Patients who underwent initial CSEMS placement for DBO between November 2014 and September 2021 were enrolled and followed-up until death, recurrent biliary obstruction, cholecystitis, or until March 2022. Cholecystitis within 30 days of CSEMS was defined as early cholecystitis and after 30 days as late cholecystitis. RESULTS: Cholecystitis occurred in 51 of 339 patients (15%) after CSEMS. Forty-one patients (80.4%) had early cholecystitis, and 10 (19.6%) had late cholecystitis. Multivariate logistic regression analysis revealed that the maximum diameter of the common bile duct (CBD) (per 1 mm increase) (odds ratio [OR]: 0.87; 95% confidence interval [CI]: 0.76-1.00; p = .044), gallbladder stones (OR: 3.63; 95% CI: 1.62-8.10; p = .002), and tumor involvement in the cystic duct (CD) (OR: 4.87; 95% CI: 2.16-11.00; p < .001) were significant independent risk factors associated with early cholecystitis. No significant risk factors were identified for late cholecystitis. CONCLUSIONS: A smaller CBD diameter, gallbladder stones, and tumor involvement in the CD were identified as risk factors for early cholecystitis development after CSEMS.

The application of low echo reduction in endoscopic ultrasound-guided tissue acquisition for pancreatic mass lesions.

Toyonaga and colleagues demonstrate, with accompanying video, the use of low echo reduction, which is a novel endoscopic ultrasound function provided by a new endoscopic ultrasound processor that increases contrast without white-out. Low echo reduction might be useful in improving lesion boundaries and needle visibility during endoscopic ultrasound-guided tissue acquisition.

Tip-in endoscopic papillectomy for ampullary adenoma near diverticulum to minimize complications.

Toyonaga and colleagues present a novel "tip-in endoscopic papillectomy" approach for resecting ampullary tumors, aiming to minimize complications like perforation and residual tumor by adapting the colonic polyp endoscopic mucosal resection tip-in method. The technique is described with accompanying video in a case of ampullary tumor near a diverticulum.

Standard versus delayed initiation of S-1 adjuvant chemotherapy after surgery for pancreatic cancer: a secondary analysis of a nationwide cohort by the Japan Pancreas Society.

BACKGROUND: Based on the Japan Adjuvant Study Group of Pancreatic Cancer-01 results, S-1 adjuvant chemotherapy has been the standard in resected pancreatic ductal adenocarcinoma (PDAC) patients in Japan and elsewhere, initiated within 10 weeks after surgery. To assess the clinical impact of this timing, we conducted a secondary analysis of a nationwide survey by the Japan Pancreas Society. METHODS: A total of 3361 patients were divided into two groups: 2681 (79.8%) initiating the therapy within 10 weeks after surgery (standard) and 680 (20.2%) after 10 weeks (delayed). We compared recurrence-free survival (RFS) and overall survival (OS) using the log-rank test and Cox proportional hazards model with conditional landmark analysis between the groups. Results were verified by adjustment with inverse-probability-of-treatment weighting (IPTW) analysis. RESULTS: The median timing of S-1 adjuvant chemotherapy initiation was 50 days (interquartile range: 38-66). In the standard group, 5-year RFS and OS rates were 32.3-48.7%, respectively, compared with 25.0-38.7% in the delayed group. Hazard ratios (HRs) and 95% confidence intervals were 0.84 (0.76-0.93) for RFS (p < 0.001) and 0.77 (0.69-0.87) for OS (p < 0.001). The IPTW analysis yielded 5-year RFS rates of 32.1% and 25.3% in the standard versus delayed group, respectively [HR = 0.86 (0.77-0.96), p < 0.001] and 5-year OS rates of 48.3% and 39.8%, respectively [HR = 0.81 (0.71-0.92), p < 0.001]. CONCLUSIONS: Initiation of S-1 adjuvant chemotherapy in resected PDAC patients within 10 weeks after surgery may offer survival benefit over later initiation.

Inhibitory effect of Ephedra herba on human norovirus infection in human intestinal organoids.

Human norovirus (HuNoV) is a major cause of acute gastroenteritis and foodborne diseases worldwide with public health concern, yet no antiviral therapies have been developed. In this study, we aimed to screen crude drugs, which are components of Japanese traditional medicine, ''Kampo'' to see their effects on HuNoV infection using a reproducible HuNoV cultivation system, stem-cell derived human intestinal organoids/enteroids (HIOs). Among the 22 crude drugs tested, Ephedra herba significantly inhibited HuNoV infection in HIOs. A time-of-drug addition experiment suggested that this crude drug more preferentially targets post-entry step than entry step for the inhibition. To our knowledge, this is the first anti-HuNoV inhibitor screen targeting crude drugs, and Ephedra herba was identified as a novel inhibitor candidate that merits further study.

Prophylactic endoscopic gallbladder stent placement for cholecystitis after covered metal stent placement for distal biliary obstruction (with video).

BACKGROUND AND AIMS: Acute cholecystitis is occasionally observed after biliary drainage using a covered self-expandable metal stent (CSEMS) for distal biliary obstruction (DBO). Gallbladder drainage before CSEMS placement may reduce cholecystitis. This study aimed to examine the preventive effect of endoscopic gallbladder stent placement (EGBS) on cholecystitis with CSEMSs. METHODS: We retrospectively analyzed patients with DBO who underwent CSEMS placement across the orifice of the cystic duct between November 2014 and October 2021 and were negative for cholecystitis on biliary drainage. Prophylactic EGBS was attempted before CSEMS placement. The incidence of cholecystitis was compared between patients with and without EGBS. RESULTS: In total, 286 patients (128 men; median age, 75 years) were included in this study. EGBS was attempted in 32 patients before CSEMS placement, and technical success was achieved in 24 patients (75%). Adverse events were noted in 3 patients (9.4%; penetration of cystic duct in 1 and acute pancreatitis in 2). The cumulative incidence of cholecystitis was significantly lower in patients with EGBS than in those without EGBS (1 [4.2%] vs 56 [21.4%], P = .045). In multivariable analysis, EGBS was a significant protective factor against cholecystitis (hazard ratio, .11; 95% confidence interval, .01-.79; P = .028). CONCLUSIONS: Although the transpapillary approach to the gallbladder is not easy for patients with DBO, EGBS is effective in preventing cholecystitis associated with CSEMS placement.