Room-temperature quantum emission from interface excitons in mixed-dimensional heterostructures

The development of van der Waals heterostructures has introduced unconventional phenomena that emerge at atomically precise interfaces. For example, interlayer excitons in two-dimensional transition metal dichalcogenides show intriguing optical properties at low temperatures. Here we report on room-temperature observation of interface excitons in mixed-dimensional heterostructures consisting of two-dimensional tungsten diselenide and one-dimensional carbon nanotubes. Bright emission peaks originating from the interface are identified, spanning a broad energy range within the telecommunication wavelengths. The effect of band alignment is investigated by systematically varying the nanotube bandgap, and we assign the new peaks to interface excitons as they only appear in type-II heterostructures. Room-temperature localization of low-energy interface excitons is indicated by extended lifetimes as well as small excitation saturation powers, and photon correlation measurements confirm antibunching. With mixed-dimensional van der Waals heterostructures where band alignment can be engineered, new opportunities for quantum photonics are envisioned.

An Analysis of Delayed Bleeding in Cases of Colorectal Endoscopic Submucosal Dissection Due to Types of Direct Oral Anticoagulants in Japan

BACKGROUND & AIMS

Reported rates of delayed bleeding (DB) after endoscopic resection using direct oral anticoagulants (DOACs) are high and heterogeneous. This large-scale multicenter study analyzed cases of DB after colorectal endoscopic submucosal dissection related to various types of DOACs in Japan (the ABCD-J study) with those associated with warfarin.

METHODS

We retrospectively reviewed 1019 lesions in patients treated with DOACs and 459 lesions in patients treated with warfarin among 34,455 endoscopic submucosal dissection cases from 47 Japanese institutions between 2012 and 2021. The DB rate (DBR) with each DOAC was compared with that with warfarin. Risk factors for DB in patients treated with DOACs or warfarin were also investigated.

RESULTS

The mean tumor sizes in the DOAC and warfarin groups were 29.6 ± 14.0 and 30.3 ± 16.4 mm, respectively. In the DOAC group, the DBR with dabigatran (18.26%) was significantly higher than that with apixaban (10.08%, P = .029), edoxaban (7.73%, P = .001), and rivaroxaban (7.21%, P < .001). Only rivaroxaban showed a significantly lower DBR than warfarin (11.76%, P = .033). In the multivariate analysis, heparin bridging therapy (odds ratio [OR], 2.18; 95% confidence interval [CI], 1.27-3.73, P = .005), rectal location (2.01, 1.28-3.16, P = .002), and procedure time ≥55 minutes (2.43, 1.49-3.95, P < .001) were significant risk factors for DB in the DOAC group. The DB risk in the DOAC group (OR, (95% CI)) was 2.13 (1.30-3.50) and 4.53 (2.52-8.15) for 1 and 2 significant risk factors, respectively.

CONCLUSIONS

Dabigatran was associated with a higher DBR than other DOACs, and only rivaroxaban was associated with a significantly lower DBR than warfarin.

A two-color dual-comb system for time-resolved measurements of ultrafast magnetization dynamics using triggerless asynchronous optical sampling

We report on an Er-doped fiber (EDF)-laser-based dual-comb system that allows us to perform triggerless asynchronous optical sampling pump-probe measurements of ultrafast demagnetization and spin precession in magnetic materials. Because the oscillation frequencies of the two frequency-comb light sources are highly stabilized, the pulse-to-pulse timing jitter is sufficiently suppressed, and data accumulation without any trigger signals is possible. To effectively induce spin precession in ferromagnetic thin films, the spectral bandwidth of the output of one of the EDF frequency comb sources is broadened by a highly nonlinear fiber and then amplified at a wavelength of about 1030 nm by a Yb-doped fiber amplifier. The output of the other frequency comb source is converted to about 775 nm by second harmonic generation. We used this system to observe ultrafast demagnetization and spin precession dynamics on the picosecond and nanosecond time scales in a permalloy thin film. This time-domain spectroscopy system is promising for the rapid characterization of spin-wave generation and propagation dynamics in magnetic materials.

[A case of autopsy-confirmed duodenal perforation due to calcium polystyrene sulfonate]

A 77-year-old male patient was referred to our hospital because of jaundice. He was diagnosed with alcoholic liver cirrhosis and was admitted to our hospital because of liver failure. After admission, we observed conservative liver disease, but the liver damage did not improve and gradually worsened. Renal function deteriorated during liver failure. Hyperkalemia presented due to renal dysfunction. Hence, calcium polystyrene sulfonate (CPS) was initiated. He died because of liver failure although hyperkalemia improved. An autopsy revealed ulcer perforation with CPS crystals in the duodenum. A basic substance considered a crystal of CPS was found by hematoxylin and eosin staining from the ulcer adjacent to the perforation and the exudate attached to the peritoneum. Furthermore, a large amount of CPS crystals were found in the ascites. A final diagnosis of gastrointestinal perforation peritonitis due to CPS was made. Gastrointestinal perforation due to CPS is presumed as a direct mucosal injury due to the drug, most of which is the sigmoid colon of elderly patients. Upper gastrointestinal tract perforation is extremely rare. We experienced a case of autopsy in which duodenal perforation due to CPS was pathologically confirmed. CPS is a widely used drug for renal disorders, but it has a risk of gastrointestinal injury. Therefore, a potential gastrointestinal mucosal injury should be considered when using CPS.

Magnifying Narrow-Band Imaging with Acetic Acid Spray for Superficial Non-Ampullary Duodenal Epithelial Tumors Based on the Mucin Phenotype

INTRODUCTION

This study aimed to identify the characteristics of superficial non-ampullary duodenal epithelial tumors (SNADETs) based on the mucin phenotype using magnifying narrow-band imaging with acetic acid spray (MA-NBI) and evaluate the efficacy of MA-NBI in differentiating gastric-type (G-type) from intestinal-type (I-type) lesions.

METHODS

We retrospectively identified 59 resected SNADETs in 59 patients who underwent MA-NBI. We evaluated surface patterns using MA-NBI to differentiate G-type from I-type lesions. Surface structures were classified into three patterns: tubular, villous, or oval structures. Lesions displaying a single pattern among the three patterns were classified as monotype, whereas those displaying multiple surface patterns were classified as mixed type. In addition, lesions with disorganized and unclear structures with irregular margins were classified as irregular surface structures.

RESULTS

In total, 32 (54%), 26 (44%), and 1 (2%) lesions were classified as Vienna category 3, 4, and 5 tumors, respectively, whereas 49 (83%) and 10 (17%) were classified as I- and G-type lesions, respectively. Oval structures were more frequently observed in G-type lesions (70%), whereas tubular structures were more frequently observed in I-type lesions (78%) (p < 0.001). Category 4 and 5 lesions had significantly higher mixed and irregular surface structure rates than category 3 lesions (41 vs. 6%, p = 0.003 and 81 vs. 3%, p < 0.001, respectively).

CONCLUSION

MA-NBI can distinguish the mucin phenotypes of SNADETs and may facilitate histological grade diagnosis.

Gli1+-PDL Cells Contribute to Alveolar Bone Homeostasis and Regeneration

The periodontal ligament (PDL) contains mesenchymal stem cells (MSCs) that can differentiate into osteoblasts, cementoblasts, and fibroblasts. Nevertheless, the distribution and characteristics of these cells remain uncertain. Gli1, an essential hedgehog signaling transcription factor, functions in undifferentiated cells during embryogenesis. Therefore, in the present study, the differentiation ability of Gli1⁺ cells was examined using Gli1-CreERT2/ROSA26-loxP-stop-loxP-tdTomato (iGli1/Tomato) mice. In 4-wk-old iGli1/Tomato mice, Gli1/Tomato⁺ cells were only slightly detected in the PDL, around endomucin-expressing blood vessels. These cells had proliferated over time, localizing in the PDL as well as on the bone and cementum surfaces at day 28. However, in 8-wk-old iGli1/Tomato mice, Gli1/Tomato⁺ cells were quiescent, as most cells were not immunoreactive for Ki-67. These cells in 8-wk-old mice exhibited high colony-forming unit fibroblast activity and were capable of osteogenic, chondrogenic, and adipogenic differentiation in vitro. In addition, after transplantation of teeth of iGli1/Tomato mice into the hypodermis of wild-type mice, Tomato fluorescence indicating the progeny of Gli1⁺ cells was detected in the osteoblasts and osteocytes of the regenerated bone. These results demonstrate that Gli1⁺ cells in the PDL were MSCs and could contribute to the alveolar bone regeneration.

Depth of the cutting plane with underwater and conventional endoscopic mucosal resection: Post-hoc analysis of a randomized study

BACKGROUND AND AIM

A multicenter randomized controlled trial reported a better R0 resection rate for intermediate-sized (10-20 mm) colorectal polyps with underwater endoscopic mucosal resection (UEMR) than conventional endoscopic mucosal resection (CEMR). To clarify whether UEMR removes enough submucosal tissue in the removal of unpredictable invasive cancers, we investigated the cutting plane depth with UEMR versus CEMR.

METHODS

This was a post-hoc analysis of a randomized controlled trial in which 210 intermediate-sized colorectal polyps were removed in five Japanese hospitals. One pathologist and two gastroenterologists independently reviewed all resected specimens and measured the cutting plane depth. The cutting plane depth was evaluated as (i) maximum depth of submucosal layer and (ii) mean depth of submucosal layer, calculated using a virtual pathology system.

RESULTS

We identified 168 appropriate specimens for the evaluation of the cutting plane depth, resected by UEMR (n = 88) and CEMR (n = 80). The median resection depth was not significantly different between UEMR and CEMR specimens, regardless of the measurement method ([i] 1317 vs 1290 μm, P = 0.52; [ii] 619 vs 545 μm, P = 0.32). All specimens in the UEMR and CEMR groups contained substantial submucosa and no muscularis propria.

CONCLUSIONS

The cutting plane depth with UEMR was comparable with that with CEMR. UEMR can be a viable alternative method that adequately resects the submucosal layer for the histopathological assessment of unpredictable submucosal invasive cancers.

Gastric Cancer with Multiple Lymph Node Enlargement at the Time of the Sarcoidosis Diagnosis

An 80-year-old woman was found to have a 40-mm depressed-type gastric cancer. Computed tomography showed multiple lymph node enlargement, including paraaortic lymph nodes. The extent of lymph node enlargement was significant compared with the depth of the primary lesion. We conducted distal gastrectomy, D2 lymph node dissection, and a paraaortic lymph node biopsy. Microscopically, the tumor was diagnosed as mucosal cancer. In the dissected lymph nodes, noncaseating granuloma was found without metastasis of adenocarcinoma. Immunohistochemical staining using Propionibacterium acnes-specific antibodies showed a large number of P. acnes-positive cells in the granulomas. Finally, the tumor was diagnosed as early-stage gastric cancer and sarcoidosis.

Efficacy of Magnifying Narrow Band Imaging with Acetic Acid Spray in Diagnosing Superficial Non-Ampullary Duodenal Epithelial Tumors

BACKGROUND/AIMS

The aim of the present study was to evaluate the efficacy of magnifying narrow band imaging with acetic acid spray (MA-NBI) in differentiating category 4/5 lesions from category 3 lesions of superficial non-ampullary duodenal epithelial tumors (SNADETs) as per Vienna Classification and to compare the diagnostic performances of both MA-NBI and magnifying narrow band imaging (M-NBI).

METHODS

We retrospectively identified 60 resected SNADETs (31 category 3 lesions and 29 category 4/5 lesions) in 60 patients who underwent M-NBI and MA-NBI preoperatively. We evaluated vascular and surface patterns using M-NBI and MA-NBI for characterizing category 3 and 4/5 lesions. The surface pattern was classified as tubular, villous, or mix structure using MA-NBI. In addition, lesions with disorganized and unclear structures with irregular margins that can be clearly recognized by MA-NBI were defined as irregular surface structures.

RESULTS

For MA-NBI, category 4/5 lesions had a significantly higher mix structure rate and higher irregular surface structure rate than category 3 lesions (62 vs. 16%, p < 0.001, and 86 vs. 19%, p < 0.001, respectively). The diagnostic accuracy of MA-NBI using mix and irregular surface structures for identifying category 4/5 lesions was as follows: sensitivity, 62/86%; specificity, 84/77%; positive predictive value, 78/78%; negative predictive value, 70/86%; and accuracy, 73/82%. The diagnostic accuracy of MA-NBI using irregular surface structure was significantly higher than that of M-NBI (p < 0.05).

CONCLUSION

MA-NBI may be useful in differentiating between category 3 and category 4/5 lesions of SNADETs.

Gastric MiNEN Arising from the Heterotopic Gastric Glands

An 80-year-old woman presented with a 30-mm protruding lesion-like submucosal tumor with a central depression located at the anterior wall of the upper gastric body. The depressed area had a well-demarcated margin, while the other area was covered by a non-neoplastic mucosa. A biopsy specimen revealed neuroendocrine carcinoma. Endoscopic ultrasonography revealed a heterogeneous mass with a clearly distinguished border in the submucosal layer. The mass had two distinct areas adjacent to each other. In addition, a hypoechoic zone was observed on the margin of the mass. Distal gastrectomy was performed. The final diagnosis was a mixed neuroendocrine-non-neuroendocrine neoplasm arising from the heterotopic gastric gland.

The impact of an empiric superior vena cava isolation added to pulmonary vein isolation for non-paroxysmal atrial fibrillation associated with left atrial low voltage areas

Introduction

Left atrial low-voltage areas (LVAs) are associated with recurrence after radiofrequency catheter ablation of atrial fibrillation (AF). However, the impact of LVAs on recurrence after an empiric pulmonary vein isolation (PVI) plus superior vena cava isolation (SVCI) strategy for non-Paroxysmal AF (PAF) patients remains unclear.

Purpose

We evaluated the impact of LVAs on the recurrence of atrial tachyarrhythmias (ATs)/AF in patients who underwent an empiric SVCI added to the PVI for non-PAF.

Methods

We enrolled 153 consecutive patients with non-PAF who underwent a PVI alone (PVI group; n=51) or empiric PVI plus SVCI (PVI+SVCI group; n=102). Left atrial voltage maps were constructed during sinus rhythm to identify the LVAs (&lt;0.5 mV). No patients underwent a substrate modification of the LVAs. We divided the patients into two groups based on the LVAs (with or without an LVA &gt;5% of the left atrial surface area) and investigated the ATs/AF free survival rate after the initial and multiple procedures.

Results

LVAs were identified in 65% and 73% of the PVI and PVI + SVCI groups, respectively (P=0.319). In the PVI group, the 18-month ATs/AF-free survival was 61% of the patients without LVAs and 27% of patients with LVAs after the initial session (P=0.018) (Figure 1-A). Seventy-two percent of the patients without LVAs and 46% of those with LVAs were free from ATs/AF after multiple sessions (P=0.083) (Figure 1-B). In the PVI+SVCI group, 50% of the patients with LVAs and 61% of those without LVAs had no recurrence after the initial session (P=0.374) (Figure 2-A). Moreover, there was no significant difference in the 18-month ATs/AF-free survival between the patients with and without LVAs after multiple sessions (73% vs. 79%; P=0.520) (Figure 2-B).

Conclusion

A PVI alone strategy for non-PAF patients with LVAs had limited efficacy for the outcomes, even with multiple procedures. However, an SVCI may have the potential to compensate for an impaired outcome in patients with LVAs.

Funding Acknowledgement

Type of funding source: None

Arterial stiffness could reflect increased cardiac load and reduced pulmonary function in the general population

Background

Pulmonary function is known to decrease with age and reduced pulmonary function has been reported to be associated with all-cause mortality and cardiovascular death. The association between pulmonary impairment and atherosclerosis was reported previously but has not been investigated sufficiently in the general population.

Purpose

We hypothesized that arterial stiffness could reflect increase of cardiac load and reduced pulmonary function. The present study aimed to investigate whether increased cardiac load and reduced pulmonary function could affect arterial stiffness in the general population.

Methods

Subjects undergoing their health check-up were enrolled. Plasma B-type natriuretic peptide (BNP) levels and serum high-sensitivity cardiac troponin I (hs-cTnI) levels were measured to evaluate cardiac load and myocardial damage. Radial augmentation index (rAI) was measured to investigate arterial stiffness using HEM-9000AI device. Subjects with an ST-T segment abnormality on the electrocardiogram, renal insufficiency, cancer, active inflammatory disease, or a history of cardiovascular events and pulmonary disease were excluded. Pulmonary function was assessed using spirometry by calculating forced vital capacity (FVC) as a percentage of predicted value (FVC%-predicted), forced expiratory volume in 1 second (FEV1) as a percentage of predicted value (FEV1%-predicted), and the ratio of FEV1 to FVC (FEV1/FVC).

Results

A total of 1100 subjects aged 57 years were enrolled and their median values of BNP and hs-cTnI were 15.5 and 2.3 pg/ml. The levels of rAI were significantly associated with the levels of BNP after adjustment for possible confounders in multivariate regression analysis, but were not with the levels of hs-TnI. While the parameters of pulmonary function were inversely associated with the levels of rAI and hs-cTnI after adjustment for possible confounders in the multivariate regression analysis, but not with the levels of BNP. The other multivariate regression analyses where BNP, hs-cTnI, parameters of pulmonary function, and the other possible factors were simultaneously included as independent variables revealed that the BNP levels and the FVC%-predicted or FEV1%-predicted, besides age, gender, smoking status, body mass index, blood pressure, heart rate, creatinine, fasting plasma glucose, and triglyceride, were significantly associated with the levels of rAI.

Conclusions

The significant associations of rAI with BNP and pulmonary function were revealed in the general population. These findings support that arterial stiffness could reflect increased cardiac load and reduced pulmonary function, in apparently healthy individuals.

Funding Acknowledgement

Type of funding source: None

[A case of concomitant pancreatic neuroendocrine neoplasm and intraductal papillary mucinous neoplasm in which preoperative diagnosis was difficult]

A 75-year-old male patient has been followed-up for mixed-type intraductal papillary mucinous neoplasm (IPMN) in the tail of the pancreas for about 20 years. Upon close examination, he was diagnosed of high-risk stigmata due to a nodule having a contrast effect of 5mm or more in the tumor. Based on this, a distal pancreatectomy was performed. Histopathological analysis revealed concomitant IPMN (low-grade) and pancreatic neuroendocrine neoplasm (PNEN) (G1). This prompted us to report a very rare case of coexisting PNEN and IPMN with an interesting pathological finding that might suggest its pathogenic mechanism.

Upper Gastrointestinal Langerhans Cell Histiocytosis: A Report of 2 Adult Cases and a Literature Review

Langerhans cell histiocytosis (LCH) with primary involvement of the upper gastrointestinal (GI) tract is rare. We report 2 adult cases of localized LCH in the upper-GI tract, including the second reported adult case of esophageal LCH and review 11 previously reported cases. Case 1 involved the esophagus of a 61-year-old man; histiocytosis was detected when endoscopy was performed for an examination of epigastric pain. Case 2 involved the stomach of a 56-year-old woman wherein the lesion was detected during a follow-up endoscopy after Helicobacter pylori infection. Both biopsy specimens exhibited diffuse proliferation of mononuclear cells with nuclear convolution and a background of eosinophilic infiltrate. The cells were immunohistochemically positive for CD1a and langerin, and BRAF V600E mutation was detected in Case 2. Follow-up endoscopy for both cases revealed that the lesions disappeared without any treatment. It is important to avoid misdiagnosing LCH of the upper-GI tract as a malignant neoplasm.

Comparison of Underwater vs Conventional Endoscopic Mucosal Resection of Intermediate-Size Colorectal Polyps

BACKGROUND & AIMS

Endoscopic mucosal resection (EMR) with submucosal injection is an established method for removing colorectal polyps, although the en bloc resection rate decreases when polyp size exceeds 10 mm. Piecemeal resection increases local recurrence. Underwater EMR (UEMR) is an effective technique for removal of sessile colorectal polyps and we investigated whether it is superior to conventional EMR (CEMR).

METHODS

We conducted a multicenter randomized controlled trial at 5 institutions in Japan. Patients with endoscopically diagnosed, intermediate-size (10-20 mm) sessile colorectal lesions were randomly assigned to undergo UEMR or CEMR. Only the most proximal lesion was registered. The UEMR procedure included immersion of the entire lumen in water and snare resection of the lesion without submucosal injection of normal saline. We analyzed outcomes of 108 colorectal lesions in the UEMR group and 102 lesions in the CEMR group. R0 resection was defined as en bloc resection with a histologically confirmed negative resection margin. The primary endpoint was the difference in the R0 resection rates between groups.

RESULTS

The proportions of R0 resections were 69% (95% confidence interval [CI] 59%-77%) in the UEMR group vs 50% (95% CI 40%-60%) in the CEMR group (P = .011). The proportions of en bloc resections were 89% (95% CI 81%-94%) in the UEMR group vs 75% (95% CI 65%-83%) in the CEMR group (P = .007). There was no significant difference in median procedure time (165 vs 175 seconds) or proportions of patients with adverse events (2.8% in the UEMR group vs 2.0% in the CEMR group).

CONCLUSIONS

In a multicenter randomized controlled trial, we found that UEMR significantly increased the proportions of R0 resections for 10- to 20-mm sessile colorectal lesions without increasing adverse events or procedure time. Use of this procedure should be encouraged. Trials registry number: UMIN000018989.

Investigation of Ag and Cu Filament Formation Inside the Metal Sulfide Layer of an Atomic Switch Based on Point-Contact Spectroscopy

The atomic switches have attracted wide attention owing to their applications in nonvolatile electric devices. The atomic switch is operated by the formation and dissipation of a metallic filament inside a metal sulfide film, which is controlled by a solid electrochemical reaction. Although the metallic filament is considered to consist of metal atoms, the chemical species of the metallic filament are difficult to be identified due to challenges in observing the metallic filament inside the solid. In this study, we report the investigation on the metallic filament in the atomic switch with metal sulfide based on point-contact spectroscopy (PCS). By cooling the atomic switch, the switch voltage increased to 1 V, which allowed for the PCS measurement. The PCS revealed that the metallic filament was composed of Ag atoms in the case of the Pt/Ag₂S/Ag atomic switch. We applied this technique to the Pt/Cu₂S/Ag and Pt/Ag₂S/Cu atomic switches to uncover the formation process of the metallic filament. In both atomic switches, the chemical species of the metallic filament were Ag. The metal atoms were supplied from both the metal electrode and the sulfide layer.

Early-stage Neuroendocrine Carcinoma of the Esophagus Observed with Annual Endoscopy for Three Years

An 80-year-old man was found to have a reddish depressed lesion on the middle thoracic esophagus. The morphology of the lesion had been almost unchanged for 3 years, but it transformed to a 2-cm depressed lesion with elevated margins and an irregular nodular surface. The lesion was resected endoscopically and ultimately diagnosed as a combined neuroendocrine carcinoma and squamous cell carcinoma with submucosal invasion. The patient was additionally treated with chemoradiotherapy but died of the primary disease eight months after the initial treatment. It is important to elucidate the natural history of this disease at an early stage.

Investigation on the formation process of metal atomic filament for metal sulfide atomic switches by electrical measurement

We have studied the formation process of the metal atomic filament for metal sulfide atomic switches by electrical measurement. The switching between ON and OFF states of the atomic switch is controlled by the application of the bias voltage for the atomic switches. The SET (OFF → ON) and RESET (ON → OFF) voltages were investigated for the atomic switch where the Ag₂S or Cu₂S layer were sandwiched between the Pt and Ag or Cu electrodes. The SET and RESET voltages of the Ag/Cu₂S/Pt and Cu/Ag₂S/Pt were close to those of the Ag/Ag₂S/Pt atomic switch, and different from those of the Cu/Cu₂S/Pt atomic switch. These results indicated that the dominant chemical species of the making and breaking part of the metal filament was Ag, and that the source of the metal filament was both the sulfide layer and the metal electrode.

In situ Raman monitoring of dielectric-heating-enhanced freeze-drying under different electromagnetic wave frequencies

We studied the effect of dielectric heating on the enhancement of freeze-drying by electromagnetic waves (EMWs) under different frequencies: 2.45 GHz microwaves (MWs), and 27 and 200 MHz radio frequencies (RFs). The irradiation with RFs, particularly at 27 MHz, reduced the duration of freeze-drying by 67%. We further analysed the water structure by in situ Raman spectroscopy during freeze-drying under EMWs. The phase transition from ice to water occurred soon after starting irradiation by MWs at 2.45 GHz, while the ice phase was almost maintained at an RF of 27 MHz.

We studied the effect of dielectric heating on the enhancement of freeze-drying by electromagnetic waves (EMWs) under different frequencies: 2.45 GHz microwaves (MWs), and 27 and 200 MHz radio frequencies (RFs).

Stretch dependent electronic structure and vibrational energy of the bipyridine single molecule junction

Change in the molecular orbital energy and vibrational energy of the bipyridine single molecule junction as a function of stretch distance.

Randomized clinical trial of high versus low inferior mesenteric artery ligation during anterior resection for rectal cancer

BACKGROUND

The optimal level for inferior mesenteric artery ligation during anterior resection for rectal cancer is controversial. The aim of this randomized trial was to clarify whether the inferior mesenteric artery should be tied at the origin (high tie) or distal to the left colic artery (low tie).

METHODS

Patients were allocated randomly to undergo either high- or low-tie ligation and were stratified by surgical approach (open or laparoscopic). The primary outcome was the incidence of anastomotic leakage. Secondary outcomes were duration of surgery, blood loss and 5-year overall survival.

RESULTS

Some 331 patients entered the trial between June 2006 and September 2012. The trial was stopped prematurely as recruitment was slow. Seven patients were excluded after randomization but before operation because of procedural changes. High tie and low tie were performed in 164 and 160 patients respectively. The incidence of anastomotic leakage was not significantly different (17·7 versus 16·3 per cent respectively; P = 0·731). The incidence of severe complications requiring intervention was 2·4 versus 5·0 per cent for high and low tie respectively (P = 0·222). In multivariable analysis, risk factors for anastomotic leakage included male sex (odds ratio 4·36, 95 per cent c.i. 1·56 to 12·18) and distance of the tumour from the anal verge (odds ratio 0·99, 0·98 to 1·00). At 5 years there were no significant differences in overall (87·2 versus 89·4 per cent respectively; P = 0·386) and disease-free (76·3 versus 77·6 per cent; P = 0·765) survival.

CONCLUSION

The level of ligation of the inferior mesenteric artery does not significantly influence the rate of anastomotic leakage. Registration number: NCT01861678 ( https://clinicaltrials.gov).

Pathotyping of Escherichia coli isolated from community toilet wastewater and stored drinking water in a slum in Bangladesh

This study investigated the occurrence of Escherichia coli pathotypes in sanitary wastewater and drinking water in a Bangladeshi urban slum and the potential associations between these sources. We examined 621 E. coli isolates from sanitary wastewater and stored drinking water by multiplex PCR and dual-index sequencing, classifying them into eight pathotypes based on 14 virulence genes and additionally evaluating the possession of the human-specific E. coli genetic biomarker H8. The proportions of pathogenic E. coli were significantly different (P < 0·001) between wastewater (18·6%) and drinking water (1·7%). StIb-positive enterotoxigenic E. coli (ETEC) were predominant in wastewater, indicating that people in the site carried ETEC. In contrast, no ETEC was present in drinking water and the proportion of H8-positive isolates was significantly smaller (7·8%) than that in wastewater (16·3%) (P = 0·001). Our findings indicate that sanitary wastewater from the slum was heavily contaminated with pathogenic E. coli, posing a great health risk. Furthermore, E. coli contamination of drinking water could be derived from not only human but also other sources.

SIGNIFICANCE AND IMPACT OF THE STUDY

Sanitary wastewater from an urban slum was heavily contaminated with pathogenic Escherichia coli. It is worth noting a great health risk of accidental exposure to pathogenically contaminated wastewater improperly discharged in and around urban slums. The distinct difference in pathotypes between wastewater and drinking water and the significantly smaller positive proportion of the human-specific E. coli genetic biomarker (H8) in drinking water indicate that drinking water contamination could be derived from not only human but also other sources. This highlights that pathotyping in association with the H8 marker provides an indication of pathogen contamination sources of environmental transmission media.

Preparation and characterization of SNO-PEG-hemoglobin as a candidate for oxygen transporting material

Acellular hemoglobin (Hb) derivates developed as oxygen carriers are known to cause hypertensive reactions due to their nitric oxide (NO) scavenging action. To modulate this undesired activity, we have developed a new Hb derivative, s-nitrosylated polyethylene glycol (PEG)-modified hemoglobin (SNO-PEG-Hb), which can deliver oxygen and NO. After human Hb was modified with PEG to increase its molecular weight, the free sulfhydryl groups of Hb were s-nitrosylated with s-nitrosoglutathione. Administration of unmodified Hb into anesthetized rats caused a hypertensive reaction, while s-nitrosylated Hb derivatives such as SNO-Hb and SNO-PEG-Hb did not raise blood pressure. The plasma half-lives of heme and NO bound to SNO-PEG-Hb were 11.5 and 2.4 hours respectively, indicating that the s-nitrosylated Hb derivative may act as a slow-releasing agent for NO. Based on these findings, SNO-PEG-Hb is a useful candidate for a blood substitute and tool for oxygen therapeutics.

Comparison of MR Imaging and Dual-Energy CT for the Evaluation of Cartilage Invasion by Laryngeal and Hypopharyngeal Squamous Cell Carcinoma

BACKGROUND AND PURPOSE

Dual-energy CT can distinguish iodine-enhanced tumors from nonossified cartilage and has been investigated for evaluating cartilage invasion in patients with laryngeal and hypopharyngeal squamous cell carcinomas. In this study, we compared the diagnostic accuracy of MR imaging and of a combination of weighted-average and iodine overlay dual-energy CT images in detecting cartilage invasion by laryngeal and hypopharyngeal squamous cell carcinomas, in particular thyroid cartilage invasion.

MATERIALS AND METHODS

Fifty-five consecutive patients who underwent 3T MR imaging and 128-slice dual-energy CT for preoperative initial staging of laryngeal or hypopharyngeal squamous cell carcinomas were included. Two blinded observers evaluated laryngeal cartilage invasion on MR imaging and dual-energy CT using a combination of weighted-average and iodine-overlay images. Pathologic findings of surgically resected specimens were used as the reference standard for evaluating sensitivity, specificity, and the areas under the receiver operating characteristic curve of both modalities for cartilage invasion by each type of cartilage and for all cartilages together. Sensitivity and specificity were compared using the McNemar test and generalized linear mixed models.

RESULTS

Dual-energy CT showed higher specificity than MR imaging for diagnosing all cartilage together (84% for MR imaging versus 98% for dual-energy CT, P < .004) and for thyroid cartilage (64% versus 100%, P < .001), with a similar average area under the curve (0.94 versus 0.95, P = .70). The sensitivity did not differ significantly for all cartilages together (97% versus 81%, P = .16) and for thyroid cartilage (100% versus 89%, P = .50), though there was a trend toward increased sensitivity with MR imaging.

CONCLUSIONS

Dual-energy CT showed higher specificity and acceptable sensitivity in diagnosing laryngeal cartilage invasion compared with MR imaging.

Impact of junction formation processes on single molecular conductance

We have investigated the electric conductance and atomic structure of single molecular junctions of pyrazine (Py), 4,4′-bipyridine (BiPy), fullerene (C₆₀), and 1,4-diaminobutane (DAB).

[A case of relapsed hemosuccus pancreaticus successfully treated with interventional radiology]

A 67-year-old male with chronic pancreatitis presented with upper abdominal pain and melena. Abdominal dynamic computed tomography revealed a splenic artery aneurysm in the main pancreatic duct. Esophagogastroduodenoscopy showed active bleeding from Vater's papilla. The patient was diagnosed with hemosuccus pancreaticus (HP) due to rupture of the aneurysm and treated with interventional radiology (IVR). The patient's poor lung function did not allow for a radical operation and a follow-up examination was recommended. The HP relapsed 7 months later and was successfully retreated with IVR. Although IVR is associated with a high recurrence rate, it is less invasive and therefore effective for treating relapsing HP in patients with a poor general condition.