Convergent approach for direct cross-coupling enabled by flash irreversible generation of cationic and anionic species

In biosynthesis multiple kinds of reactive intermediates are generated, transported, and reacted across different parts of organisms, enabling highly sophisticated synthetic reactions. Herein we report a convergent synthetic approach, which utilizes dual intermediates of cationic and carbanionic species in a single step, hinted at by the ideal reaction conditions. By reactions of unsaturated precursors, such as enamines, with a superacid in a flow microreactor, cationic species, such as iminium ions, are generated rapidly and irreversibly, and before decomposition, they are transported to react with rapidly and independently generated carbanions, enabling direct C-C bond formation. Taking advantage of the reactivity of these double reactive intermediates, the reaction take place within a few seconds, enabling synthetic reactions which are not applicable in conventional reactions.

Investigation of vertical margin involvement in endoscopic resection for T1 colorectal cancer

OBJECTIVES

The resection of vertical margin-negative submucosally invasive colorectal cancer (CRC) relies on the pathological risk assessment of lymph node metastasis. However, no large-scale study has clarified the endoscopic resection (ER) outcome for submucosally invasive CRC, focusing on the vertical margin status. This retrospective study aimed to examine vertical margin involvement in ER for submucosally invasive CRC and explore the treatment consequences associated with vertical margin status.

METHODS

We analyzed 395 submucosally invasive CRC cases in 389 patients who underwent ER at our hospital between 2008 and 2020. The presence of residual tumors and simultaneous lymph node metastasis in patients who underwent additional surgery was assessed and compared between the vertical incomplete ER and the vertical margin-negative groups.

RESULTS

Among the patients, 270 were men, with a median age of 69 years. The vertical incomplete ER rate was 21.5%, with positive vertical margins and unclear vertical margins identified in 12.2% and 9.3% of the cases, respectively. Among 154 patients who underwent additional surgery after ER, the vertical incomplete ER group had a significantly higher residual tumor rate than the vertical margin-negative group (P = 0.001). The vertical incomplete ER group had a significantly higher lymph node metastasis rate than the vertical margin-negative group (P = 0.029).

CONCLUSION

This study clarified the substantial risk of vertical incomplete ER in submucosally invasive CRC and revealed the high risk of residual tumor and lymph node metastasis in vertical incomplete ER for submucosal CRC.

Quantitative Analysis of the Concentration of Trifluridine in Tumor Hypoxic Regions Using a Novel Platform Combining Functional Endoscopy and Mass Spectrometry

Hypoxic regions in solid tumors are highly resistant to drugs and thus represents an obstacle in drug discovery. Currently, however, there are technical barriers in sampling human hypoxic tumors and examining drug delivery with high sensitivity and accuracy. Herein, we present a new platform combining functional endoscopy and highly sensitive liquid chromatography-mass spectrometry (LC-MS) to assess drug delivery to hypoxic regions. Because oxygen saturation endoscopic imaging (OXEI), a functional endoscopy, can evaluate lesions and hypoxia in real-time by simultaneously acquiring a pseudocolor map of oxygen saturation and conventional endoscopic images, this platform can be used to evaluate drug delivery with human samples from hypoxic regions. As the first clinical application of this platform, the relationship between hypoxic regions and the concentration of trifluridine (FTD) incorporated into DNA was evaluated in patients with advanced gastric cancer treated with FTD/tipiracil (FTD/TPI; n = 13) by obtaining and analysis of tissue samples by OXEI and LC-MS and vascular maturity index by CD31/α-SMA staining ex vivo. The results showed that the concentration of FTD was significantly higher in the normoxic region than in the hypoxic region (P < 0.05) and there were significantly more immature vessels in hypoxic regions than in normoxic regions (P < 0.05). These results indicate that the platform was sufficiently sensitive to evaluate differences in drug anabolism in different oxygenic regions of human tumor tissue. This new platform allows quantitative drug analysis in hypoxic regions and is expected to initiate a new era of drug discovery and development.

Hot snare polypectomy vs endoscopic mucosal resection using bipolar snare for intermediate size colorectal lesions: Propensity score matching

BACKGROUND

Endoscopic resection (ER) with bipolar snare, in which the electric current only passes through the tissue between the device’s two electrodes, is a prominent method used to prevent perforation due to electricity potentially. ER using bipolar snare with or without submucosal injection enabled safe resection of colorectal lesions measuring 10–15 mm in an ex vivo porcine model. ER with bipolar snare is expected to have good treatment outcomes in 10–15 mm colorectal lesions, with high safety even without submucosal injection. However, no clinical reports have compared treatment outcomes with and without submucosal injection.

AIM

To compare the treatment outcomes of bipolar polypectomy with hot snare polypectomy (HSP) to those with endoscopic mucosal resection (EMR).

METHODS

In this single-centre retrospective study, we enrolled 10–15 mm nonpedunculated colorectal lesions (565 Lesions in 463 patients) diagnosed as type 2A based on the Japan Narrow-band Imaging Expert Team classification, resected by either HSP or EMR between January 2018 and June 2021 at the National Cancer Center Hospital East. Lesions were divided into HSP and EMR groups, and propensity score matching was performed. In the matched cohort, en bloc and R0 resection rates and adverse events were compared between the two groups.

RESULTS

Of the 565 lesions in 463 patients, 117 lesions each in the HSP and EMR groups were selected after propensity score matching. In the original cohort, there was a significant difference in antithrombotic drug use (P < 0.05), lesion size (P < 0.01), location (P < 0.01), and macroscopic type (P < 0.05) between the HSP and EMR groups. In the matched cohort, the en bloc resection rates were comparable between both groups [93.2% (109/117) vs 92.3% (108/117), P = 0.81], and there was no significant difference in the R0 resection rate [77.8% (91/117) vs 80.3% (94/117), P = 0.64]. The incidence of delayed bleeding was similar in both groups [1.7% (2/117)]. Perforation occurred in the EMR group [0.9% (1/117)] but not in the HSP group.

CONCLUSION

Using bipolar snare, ER of nonpedunculated 10–15 mm colorectal lesions may be performed safely and effectively, even without submucosal injection.

Design of a highly sensitive and versatile membrane-based immunosensor using a Cu-free click reaction

A highly sensitive immunosensor is developed using membrane pores as the recognition interface. In this sensor, a Cu-free click reaction is used to efficiently immobilize antibodies, and the sensor inhibits the adsorption of nonspecific proteins that degrade sensitivity. Furthermore, the sensor demonstrates rapid interleukin-6 detection in the picogram per milliliter range.

Prospective study on the risk of transmission due to droplets and aerosols during an endoscopic procedure and the usefulness of extraoral suction devices

OBJECTIVES

Endoscopy poses a high risk of severe acute respiratory syndrome coronavirus 2 infection for medical personnel due to the dispersal of aerosols from the patient. We investigated the location and size of droplets generated during esophagogastroduodenoscopy (EGD) and endoscopic submucosal dissection (ESD), the contamination of the surrounding area before and after the procedures, and the effectiveness of using an extraoral suction device (Free arm arteo; TOKYO GIKEN, Inc., Tokyo, Japan).

METHODS

Patients who consented to the study and underwent EGD or ESD between December 8, 2020, and April 15, 2021, at the National Cancer Center East Hospital were included. Adenosine triphosphate (ATP) hygiene monitoring tests and a particle counter were used for measurements.

RESULTS

Assessments were performed on 22 EGD and 15 ESD cases. ATP hygiene monitoring tests showed significant elevations at three sites near the patient, and two sites 1.5 m away, for EGD, and at four sites near the patient and 1.5 m away for ESD. In both ESD and EGD, extraoral suction devices reduced the extent of the contamination. Particles <5 μm in size were generated during endoscopic procedures and dispersed from both the forceps hole and the patient's mouth. The extraoral suction device did not reduce the number of particles generated.

CONCLUSIONS

During endoscopic procedures, cleaning the surrounding environment is important in addition to standard precautions the endoscopist and caregivers take. The use of extraoral suction devices can also potentially reduce contamination of the surrounding environment.

Direct identification of the rotary angle of ATP cleavage in F1-ATPase from Bacillus PS3

F1-ATPase is the world's smallest biological rotary motor driven by ATP hydrolysis at three catalytic β subunits. The 120° rotational step of the central shaft γ consists of 80° substep driven by ATP binding and a subsequent 40° substep. In order to correlate timing of ATP cleavage at a specific catalytic site with a rotary angle, we designed a new F1-ATPase (F1) from thermophilic Bacillus PS3 carrying β(E190D/F414E/F420E) mutations, which cause extremely slow rates of both ATP cleavage and ATP binding. We produced an F1 molecule that consists of one mutant β and two wild-type βs (hybrid F1). As a result, the new hybrid F1 showed two pausing angles that are separated by 200°. They are attributable to two slowed reaction steps in the mutated β, thus providing the direct evidence that ATP cleavage occurs at 200° rather than 80° subsequent to ATP binding at 0°. This scenario resolves the long-standing unclarified issue in the chemomechanical coupling scheme and gives insights into the mechanism of driving unidirectional rotation.

Reduction of noise induced by power supply lines using phase-locked loop

An experimental implementation for the reduction of power-line noise in delicate signal detection is presented. This implementation improves the signal-to-noise ratio without limiting the bandwidth of the measurement. A sinusoidal wave and its harmonics, both synchronized with the frequency of the power line, are used to cancel out the power supply noise induced in the measurement signal. The wave and the harmonics are generated via a phase-locked loop implementation. Their amplitude and phase are adjusted, and then they are added to the measurement signal using a series of operational amplifiers to compensate for the noise. Although we applied this method to the particular case of scanning tunneling microscopy measurements, considerably improving the image quality, our implementation can be applied to other measurement systems for which noise from the power lines can compromise the signal detection.

Recurrent metastasis risk factors in esophageal cancer after salvage endoscopic resection for local failure following chemoradiotherapy

OBJECTIVES

Although salvage endoscopic resection is an optimal treatment for local failure after chemoradiotherapy for esophageal squamous cell carcinoma, recurrent metastasis (lymph node and/or distant metastasis) after salvage endoscopic resection may occur with a certain degree of unavoidable frequency and is associated with a poor prognosis. However, the risk factors for recurrent metastasis are unclear. This study aimed to evaluate the risk factors for recurrent metastasis after salvage endoscopic resection.

METHODS

Patients who underwent salvage endoscopic resection for local failure after chemoradiotherapy/radiotherapy were analyzed in this single-center, retrospective study. We evaluated the cumulative incidence rates of recurrent metastases, overall survival, and the risk factors for recurrent metastasis after salvage endoscopic resection.

RESULTS

We analyzed 132 patients. The 5-year cumulative incidence rate of recurrent metastases after salvage endoscopic resection was 25.7%. The 5-year overall survival rates in all patients and in patients with recurrent metastasis were 66.8% and 22.5%, respectively. Local failure pattern with a residual lesion after chemoradiotherapy/radiotherapy (subdistribution hazard ratio 2.34; P = 0.012) and the presence of lymphatic invasion in salvage endoscopic resection specimen (subdistribution hazard ratio 3.20; P = 0.002) were significant risk factors for recurrent metastasis.

CONCLUSIONS

Patients with local failure pattern with a residual lesion after chemoradiotherapy/radiotherapy and presence of lymphatic invasion have a high risk for recurrent metastasis. Thus, appropriate surveillance for these patients should be considered.

P-199 Effect of the area of oocyte perivitelline space on the fertilization and embryo development following intracytoplasmic sperm injection

Study question

Does the area of oocyte perivitelline space have an effect on fertilization and embryo development following intracytoplasmic sperm injection?

Summary answer

The area of oocyte perivitelline space has not an effect on the fertilization but the embryo development following intracytoplasmic sperm injection.

What is known already

Oocyte perivitelline space has a lot of variation at intracytoplasmic sperm injection (ICSI). Some researchers reported that the characteristics of perivitelline space (large or small) affect embryo development, pregnancy, and implantation. However, these studies did not accurately calculate the area of perivitelline space. Therefore, little information is available on the effect of the area of oocyte perivitelline space on fertilization and embryo development following ICSI. The purpose of this study was to calculate and classify the area of oocyte perivitelline space and investigate the effect of the area of perivitelline space on fertilization and embryo development following ICSI.

Study design, size, duration

1. We retrospectively investigated 634 mature oocytes that were conducted ICSI between January 2021 and December 2021. The area of each oocyte perivitelline space was defined from between the area of circle calculated from the inner layer of zona pellucida and cytoplasm and divided into 3 groups (-9%, 10-19%, 20%-).

2. We retrospectively calculated the diameter of an inner layer of zona pellucida and cytoplasm and compared it with the 3 groups (-9%, 10-19%, 20%-).

Participants/materials, setting, methods

1. The fertilization, survival, good quality day-3 embryo, blastocyst, good quality blastocyst rates following ICSI were compared with the 3 groups (-9%, 10-19%, 20%-).

2. The average diameter of an inner layer of zona pellucida and cytoplasm of each oocyte for the 3 groups (-9%, 10-19%, 20%-) were compared.

The data were analyzed by Fisher’s exact test, residual analysis, one-way ANOVA test, with Bonferroni correction as appropriate to determine the statistical differences among groups.

Main results and the role of chance

1. The survival rates of perivitelline space -9%, 10-19%, 20%- groups were 100% (109/109), 96% (363/378), 94% (138/147), the fertilization rates were 89% (97/109), 88% (331/378), 86% (127/147), the good quality day-3 embryo rates were 56% (54/97), 70% (232/331), 70% (89/127) respectively. No significant difference was observed between these comparison items. The blastocyst rates of perivitelline space -9%, 10-19%, 20%- groups were 51% (47/92), 69% (222/321), 82% (93/114), the good quality blastocyst rates were 22% (20/92), 40% (129/321), 52% (59/114) respectively. The blastocyst and good quality blastocyst rates of perivitelline space -9% group showed significantly lower results. On the other hand, the blastocyst and good quality blastocyst rates of perivitelline space 20%- group showed significantly higher results.

2. The average diameter of an inner layer of zona pellucida of perivitelline space -9%, 10-19%, 20%- groups were 125 ± 4 µm, 129 ± 5 µm, 136 ± 6 µm, the average diameter of the cytoplasm of perivitelline space were 121 ± 4 µm, 119 ± 4 µm, 118 ± 4 µm respectively. Significant differences were observed in all pairs of groups of the average diameter of an inner layer of zona pellucida and cytoplasm.

Limitations, reasons for caution

The area of oocyte perivitelline space was calculated at only one plane.

Wider implications of the findings

Oocytes with narrow perivitelline space might have a wide region of adhesive between the cytoplasm surface and an inner layer of the zona pellucida which resulted in a smaller diameter of the zona pellucida and lower blastocyst rate by forming cytoplasmic fragments (Yumoto K et al. JARG. 2020 ;37(6):1349-1354.).

Trial registration number

Not Applicable

Salvage endoscopic resection for cT1N0M0 local recurrence after chemoradiotherapy for esophageal squamous cell carcinoma: endoscopic submucosal dissection versus endoscopic mucosal resection

OBJECTIVES

Salvage endoscopic resection is recommended when the local recurrence at primary site after chemoradiotherapy for esophageal squamous cell carcinoma is localized and superficial. This retrospective study aimed to comparatively analyse the short-term outcomes and local control of salvage endoscopic submucosal dissection versus salvage endoscopic mucosal resection for local recurrence after chemoradiotherapy or radiotherapy.

METHODS

A total of 96 patients who underwent initial salvage endoscopic resection for cT1N0M0 local recurrence after chemoradiotherapy or radiotherapy for esophageal squamous cell carcinoma between December 1998 and August 2019 patients were assigned to either the salvage endoscopic submucosal dissection (40 patients; 40 lesions) or salvage endoscopic mucosal resection (56 patients; 56 lesions) group. We evaluated the en bloc and R0 resection rates, severe adverse events and local failure rate after salvage endoscopic resection. Multivariate analysis was conducted to identify risk factors of local failure after salvage endoscopic resection.

RESULTS

The en bloc resection rate was significantly higher in the salvage endoscopic submucosal dissection group than in the salvage endoscopic mucosal resection group (95% versus 63%; P < 0.001). There were no differences in R0 resection rate between the two groups (73% versus 52%, P = 0.057). One patient (3%) in the salvage endoscopic submucosal dissection group had perforation. The 3-year cumulative local failure rate of salvage endoscopic mucosal resection was significantly higher than that of salvage endoscopic submucosal dissection (27% versus 5%, P = 0.032). In multivariate analysis, salvage endoscopic mucosal resection (hazard ratio: 2.7, P = 0.044) was the only independent risk factor of local failure after salvage endoscopic resection.

CONCLUSIONS

Salvage endoscopic submucosal dissection is the effective treatment for local recurrence based on the short-term outcomes and local efficacy.

Efficacy and safety of second photodynamic therapy for local failure after salvage photodynamic therapy for esophageal cancer

OBJECTIVES

Photodynamic therapy (PDT) is an optional salvage treatment for local failure of esophageal squamous cell carcinoma (ESCC) after chemoradiotherapy; however, local failure after PDT sometimes occurs. In such cases, second PDT is sometimes attempted, but its outcomes remain unclear. This study aimed to evaluate the efficacy and safety of second PDT.

METHODS

We enrolled patients who underwent PDT for local failure of ESCC after chemoradiotherapy. We retrospectively evaluated local-complete response (L-CR) rate and clinical outcomes of first and second PDT. The indications for PDT were lesions within the muscle layer, <3 cm in size, and <3/4 of the esophageal circumference; not suitable for salvage surgery; and absence of metastasis. Second PDT was avoided when lesions were apparently refractory to first PDT, e.g. persistence of submucosal tumor-like protruded component or rapid regrowth of tumor at the ulceration after first PDT. L-CR was defined as endoscopic disappearance of tumor and post-PDT ulcer and absence of cancer cells histologically.

RESULTS

Among 82 patients who underwent first PDT, 27 underwent second PDT. The L-CR rates with first and second PDT were 63.0% and 40.7%, respectively. The 2-year overall survival rates after second PDT in patients with L-CR and local-nonCR were 79.5% and 40.5%, respectively. Five of 11 patients with L-CR survived without any recurrence. No grade ≥3 adverse events occurred.

CONCLUSIONS

Second PDT demonstrated excellent safety and acceptable efficacy; therefore, it could be a useful treatment for local failure after first PDT.

AB0391 LOW SERUM COMPLEMENT C3 LEVEL AS A RISK FACTOR FOR RELAPSE OF ANTINEUTROPHIL CYTOPLASMIC ANTIBODY-ASSOCIATED VASCULITIS: A RETROSPECTIVE COHORT STUDY

Background:

The alternative pathway of complement activation has recently been recognized as a key pathogenic event in antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV). Some previous studies have reported that low serum complement C3 level in AAV patients is associated with more severe renal disease, worse renal prognosis, or higher mortality. However, the correlation between low serum C3 level and AAV relapse remains unclear.

Objectives:

To analyze the clinical characteristics and outcomes of AAV patients with low serum C3 levels at the time of diagnosis.

Methods:

We conducted a retrospective observational cohort study including 83 consecutive patients diagnosed with AAV in our hospital from January 1999 to December 2020. Serum C3 levels were measured at diagnosis. AAV included microscopic polyangiitis (MPA), granulomatosis with polyangiitis (GPA), and eosinophilic granulomatosis with polyangiitis (EGPA); patients with ANCA-negative AAV were excluded. Patients were divided into low- and high-C3 groups (C3 < 100 and ≥ 100 mg/dL, respectively). We compared the clinical characteristics, and relapse-free and overall survival rates, of the two groups, and identified predictors of AAV relapse.

Results:

Of the 83 patients (MPA, n = 61; GPA, n = 18; EGPA, n = 4), 20 (24%) were in the low-C3 group. We found no significant group difference in sex, body mass index, disease type, ANCA subtype, Birmingham Vasculitis Activity Score (BVAS), or treatment. The low-C3 group patients were older (p=0.01), and had a higher Five Factor Score (FFS) (p=0.01) and a lower remission rate (p=0.02), than the high-C3 group. The generalized Wilcoxon test revealed that the relapse-free survival time was significantly shorter in the low-C3 group (29 months; 95% confidence interval [CI]: 15–49) than in the high-C3 group (82 months; 95% CI: 61–NA; p=0.01) (Figure 1A). The overall survival was also shorter in the low-C3 group (83 months; 95% CI: 8-121) than in the high-C3 group (112 months; 95% CI: 77-NA; p=0.03) (Figure 1B). In the Cox proportional hazards model, a low C3 level (< 100 mg/dL) (hazard ratio [HR], 3.01; 95% CI: 1.29–7.04], p=0.01) and GPA (HR, 3.04; 95% CI: 1.32–7.01; p=0.01) were independent predictors of AAV relapse.

Figure 1.

Kaplan-Meier estimates of the relapse-free (A) and overall (B) survival rates of AAV patients by baseline serum C3 levels. Eight patients who did not show remission were excluded in the relapse-free survival analysis. Black line: high-C3 group (≥ 100 mg/dL); red line: low-C3 group (< 100 mg/dL).

Conclusion:

AAV patients with low C3 levels at diagnosis were at higher risk of relapse. Larger prospective studies are required to confirm these findings.

Disclosure of Interests:

None declared