Intragastric free cancer cells may be attached to automatic staplers during anastomosis in patients with gastric cancer.

BACKGROUND: Automatic staplers are often used to reconstruct the digestive tract during surgeries for gastric cancer. Intragastric free cancer cells adhering to automatic staplers may come in contact with the laparoscopic port area and progress to port site recurrence. This study aimed to investigate the presence/absence of cancer cells adhering to automatic staplers during gastric cancer surgery using cytological examinations. We further determined the positive predictive clinicopathological factors and clinical implications of free cancer cells attached to automatic staplers. METHODS: This study included 101 patients who underwent distal gastrectomy for gastric cancer. Automatic staplers used for anastomosis in gastric cancer surgeries were shaken in 150 ml of saline solution to collect the attached cells. Papanicolaou stains were performed. We tested the correlation between cancer-cell positivity and clinicopathological factors to identify risk factors arising from the presence of attached cancer cells to the staplers. RESULTS: Based on the cytology, cancer cells were detected in 7 of 101 (6.9%) stapler washing fluid samples. Univariate analysis revealed that circular staplers, type 1 tumors, and positive lymph nodes were significantly associated with higher detection of free cancer cells adhering to staplers. No significant differences in other factors were detected. Of the seven cases with positive cytology, one developed anastomotic recurrence. CONCLUSIONS: Exfoliated cancer cells adhered to the automatic staplers used for anastomoses in 6.9% of the staplers used for distal gastrectomies in patients with gastric cancer. Staplers used for gastric cancer surgeries should be handled carefully.

Resident performance in simulation module is associated with operating room performance for laparoscopic cholecystectomy.

BACKGROUND: Simulation is an important tool in surgical training. However, the transferability of skills obtained in the simulation setting to the operating room (OR) is uncertain. This study explores the association between resident simulation performance and OR performance in a laparoscopic cholecystectomy (LC) simulation module. METHODS: A simulation module focused on LC utilizing a virtual reality simulator was completed by general surgery residents. Simulation performance was evaluated using the validated Global Operative Assessment of Laparoscopic Skills (GOALS) and Objective Structured Assessment of Technical Skills (OSATS), as well as a LC-specific simulation assessment form (LC-SIM). Resident subsequent OR performances of LC were measured by the Surgical Training and Assessment Tool (STAT), an online mobile-based evaluation completed by attending surgeons. RESULTS: Twenty-one residents who completed the simulation module and also with STAT data on LC from 2016 to 2020 were included. Higher scores on incision/port placement on LC-SIM is associated with better tissue handling (coefficient 0.20, p = 0.048) and better time & economy of motion on STAT (coefficient 0.22, p = 0.037). However, higher scores on time and motion on OSATS are associated with worse tissue handling (- 0.28, p = 0.046), worse time & economy of motion (- 0.37, p = 0.009), and worse overall grade (- 0.21, p = 0.044). Higher scores on overall performance on OSATS is associated with worse time & economy of motion (- 0.80, p = 0.008). Higher scores on depth perception on GOALS are associated with worse tissue handling (- 0.28, p = 0.044). CONCLUSION: We found significant positive and negative associations between resident simulation performance and OR performance, particularly in tissue handling and economy of motion. This could suggest that simulation performance does not reliably predict OR performance. However, this could highlight the concept of excessive caution in the real OR environment and longer operative time which could be interpreted as worse time and economy of motion by the attending surgeons.

Subjective vs. objective assessment of simulation performance on laparoscopic cholecystectomy: are we evaluating the right things?

BACKGROUND: Simulation using virtual reality (VR) simulators is an important tool in surgical training. VR laparoscopic simulators can provide immediate objective performance assessment without observer evaluation. This study aims to explore the correlation between subjective observer evaluation and VR laparoscopic simulator performance metrics in a laparoscopic cholecystectomy (LC) simulation module. METHODS: A LC simulation module using a VR laparoscopic simulator was completed by PGY2-3 general surgery residents at a single institution. Simulation performance was recorded and evaluated by a trained evaluator using the validated Global Operative Assessment of Laparoscopic Skills (GOALS) form, the Objective Structured Assessment of Technical Skills (OSATS) form, and a LC-specific simulation assessment form (LC-SIM). Objective performance metrics were also obtained from the simulator system. Performance before the curriculum (pre-test) and after the curriculum (post-test) were compared. RESULTS: Fourteen residents were included in the study. There were significant improvements from pre-test to post-test on each component of GOALS, OSATS, and LC-SIM scores (all p values < 0.05). In terms of objective simulator metrics, significant improvements were noted in time to extract gallbladder (481 ± 221 vs 909 ± 366 min, p = 0.019), total number of movements (475 ± 264 vs 839 ± 324 min, p = 0.012), and total path length (955 ± 475 vs 1775 ± 632 cm, p = 0.012) from pre-test to post-test. While number of movements and total path lengths of both hands decreased, speed of right instrument also decreased from 4.1 + 2.7 to 3.0 ± 0.7 cm/sec (p = 0.007). Average speed of left instrument was associated with respect for tissue (r = 0.60, p < 0.05) and depth perception (r = 0.68, p < 0.05) on post-test evaluations. CONCLUSION: Our study demonstrated significant improvement in technical skills based on subjective evaluator assessment as well as objective simulator metrics after simulation. The few correlations identified between the subjective evaluator and the objective simulator assessments suggest the two evaluation modalities were measuring different aspects of the technical skills and should both be considered in the evaluation process.

Long-term retention after structured curriculum on attainment of critical view of safety during laparoscopic cholecystectomy for surgeons.

BACKGROUND: Obtaining a clear Critical View of Safety helps prevent bile duct injuries during laparoscopic cholecystectomy, which can be improved with a structured Safe Critical View of Safety curriculum. We aimed to determine whether the improvement in obtaining Critical View of Safety postcurriculum is retained long-term. METHODS: A safe Critical View of Safety curriculum was previously implemented for all surgeons who perform laparoscopic cholecystectomy at a regional health system. Recordings of laparoscopic cholecystectomy cases were collected 1 year after completion of the curriculum, deidentified and randomly ordered, and then graded by 2 blinded expert surgeons using a 6-point Critical View of Safety assessment tool. RESULTS: A total of 12 surgeons with average experience of 17.9 ± 6.3 years in practice participated in the study. The majority (83%) had performed >700 laparoscopic cholecystectomies, and 4 surgeons (33%) reported 2 or more bile duct injuries in their career. Controlling for gallbladder pathology, Critical View of Safety scores improved from 1.7 ± 0.4 to 4.0 ± 0.4 (P < .001) immediately after completion of the curriculum. However, there was a small decrease in Critical View of Safety score after 1 year (3.2 ± 0.3 from 4.0 ± 0.4, P = .055), while still significantly higher compared to precurriculum (3.2 ± 0.3 vs 1.7 ± 0.4, P < .001). Acute care surgeons had lower Critical View of Safety retention scores compared to general surgeons (1.8 ± 0.5 vs 3.3 ± 0.4, P = .01) and minimally invasive surgeons (1.8 ± 0.5 vs 3.8 ± 0.5, P < .01). CONCLUSION: A structured curriculum helped improve practicing surgeons' attainment of obtaining the Critical View of Safety during laparoscopic cholecystectomy. However, this improvement decreased after 1 year, suggesting some decay in knowledge retention over time. Therefore, continued educational interventions on Critical View of Safety and safe laparoscopic cholecystectomy may be needed to enhance long-term retention.

Synthesis and n-Type Semiconducting Properties of Bis(dioxaborin) Compounds Containing a π-Extended 2,2'-Bithiophene Structure.

Bis(dioxaborin) compounds containing π-conjugated systems have been studied as n-type semiconductors for organic field-effect transistors (OFETs). In this study, with the aim of investigating the effect of the extension of the π-conjugation on the n-type semiconducting properties and stability of bis(dioxaborin) compounds, we synthesized new compounds containing 2,2'-bithiophene derivatives extended with an olefin or an acetylene spacer. The absorption maxima of the compounds containing olefin spacers were greatly red-shifted compared with those of the original compound without a π-spacer. The newly synthesized compounds exhibited high electron affinity, and the olefin spacers effectively reduced the on-site Coulomb repulsion in the two-electron reduction of the compounds. An OFET fabricated using one of these compounds having a layer-by-layer crystal structure exhibited n-type semiconductor behavior with a low threshold voltage, most likely due to the small on-site Coulomb repulsion. The electron-transporting properties were investigated by theoretical calculations based on the Marcus theory.

Next-Generation Sequencing for Non-Ampullary Duodenal Carcinoma Suggesting the Existence of an Adenoma-Carcinoma Sequence.

Duodenal tumors with a sporadic adenoma-carcinoma sequence are extremely rare. For such clinically suspected cases without a specific family history, performing a comprehensive gene search is important to understand the germline mutation background. We present a 68-year-old woman without a genetic or familial history of familial adenomatous polyposis (FAP), Peutz-Jeghers syndrome, or Lynch syndrome who presented to Kosei Hospital, Japan, with exertional dyspnea induced by abdominal pain lasting 3 weeks. A duodenal tumor was suspected by contrast-enhanced computed tomography. Esophagogastroduodenoscopy showed a lesion accompanied by a white microprotuberance on the descending part of the duodenum opposite the papilla, with a giant ulcerative lesion at the center of the white lesion. Biopsy revealed a low-grade adenoma, high-grade adenoma, and adenocarcinoma. Immunohistochemical analysis of the adenoma and adenocarcinoma showed Ki-67, p53, cytokeratin 20, caudal-type homeobox 2, and carcinoembryonic antigen positivity and cytokeratin 7 negativity. The findings suggested the presence of an adenoma-adenocarcinoma sequence in duodenal carcinoma. However, in the mutational analysis using next-generation sequencing, c.4348C>T (p.Arg1450Ter) mutation in APC was detected in all normal mucosal, adenoma, and carcinoma tissues. This mutation is common in FAP patients. Even if the presence of an adenoma-adenocarcinoma sequence in duodenal carcinoma is suggested in cases without a familial FAP history, as in this case, genetic analysis may reveal FAP. Thus, performing a comprehensive genetic analysis of duodenal carcinoma patients with a possible adenoma-carcinoma sequence is necessary to explore their genetic background.

Ascending Colon Schwannoma Surgically Treated after Accurate Preoperative Diagnosis.

Colorectal schwannomas are rare and usually benign gastrointestinal mesenchymal tumors. However, these tumors are often overtreated, possibly owing to misleading malignant potential. To our knowledge, there have been no previous reports of ascending colon schwannoma preoperatively diagnosed as benign schwannoma. Herein, we report a case of ascending colon schwannoma accurately diagnosed by endoscopic biopsy and successfully treated by wedge resection. The patient was a 76-year-old woman with complaints of bloody stool. She had no relevant past medical history. Radiological findings revealed a protruded mass in the ascending colon, and colonoscopy revealed a submucosal tumor measuring approximately 3 cm in diameter with a reddish and uneven surface. Histological and immunohistochemical analysis for vimentin and S100 protein of the specimen obtained by endoscopic biopsy confirmed the diagnosis of schwannoma. Thus, we performed laparoscopy-assisted endoscopic full-thickness resection of the ascending colon wall, as appropriate for a benign soft tissue tumor. The postoperative course has been uneventful for 2 years. This case demonstrates that colonic schwannoma can be successfully treated with adequate resection if an accurate preoperative diagnosis is made, thereby avoiding overtreatment, such as surgery for colorectal tumor including lymph node dissection. Preoperatively diagnosed schwannomas should be treated by wedge resection, with postoperative pathological findings confirming the presence or absence of malignancy. Additional resection should be considered for very rare cases of coexisting malignant tissue.

STK11 p.F354L Germline Mutation in a Case of Multiple Gastrointestinal Tumors.

Serine/threonine kinase 11 (STK11) is known as a critical tumor-suppressor gene that is frequently mutated in a broad spectrum of human cancers. Among these, the p.F354L mutation of STK11 has been identified in sporadic colon or lung cancer cases. Here, we report the case of a 75-year-old male patient who underwent surgical treatment for multiple tumors of the gastrointestinal system. Genetic mutations were screened in all resected samples, including duodenal high-grade adenoma, gastric high-grade adenoma, rectal adenocarcinoma, and liver metastasis of rectal adenocarcinoma, by next-generation sequencing for mutational hotspots involving 50 oncogenes and tumor suppressor genes. The characteristic hamartomatous polyp of Peutz-Jeghers syndrome was not detected in any tumor specimen. However, all samples as well as the normal rectal mucosa harbored the genetic mutation p.F354L in STK11. In addition, somatic mutations coexisted in the tumor samples, including KRAS p.A146T, TP53 p.G238X, and APC p.T1556fs in the duodenal adenoma; TP53 p.G238Y and APC p.T1556fs in the gastric adenoma; and TP53 p.R282W in the rectal adenocarcinoma and metastatic liver cancer. No somatic mutation was detected in the normal rectal mucosa as a control sample. To our knowledge, this is the first report of an STK11 germline mutation in a patient with multiple tumors of the gastrointestinal tract.

APC:T1556fs and STK11 mutations in duodenal adenomas and adenocarcinomas.

PURPOSE: Duodenal adenoma and adenocarcinoma (AC) are rare tumors, and few studies have examined their genetic features. We aimed to determine the key genetic changes in duodenal adenoma and AC, and to clarify the possible involvement of the adenoma-carcinoma sequence in duodenal tumor carcinogenesis. METHODS: Nineteen duodenal tumors collected by endoscopic mucosal resection or surgical resection were classified as AC, adenoma with high-grade dysplasia (HGD), or adenoma with low-grade dysplasia (LGD) per the World Health Organization tumor classification. When a tumor contained two or more components with different dysplasia grades, the highest grade was assigned as the tumor grade. Representative areas of these components with different grades were microdissected and evaluated by a genomic analysis. Mutational hotspots involving 50 oncogenes and tumor suppressor genes were analyzed by next-generation sequencing, and their association with the dysplasia grade was investigated. RESULTS: We analyzed 27 tumor components of AC or adenoma, with 11 normal mucosal samples obtained from 19 patients with duodenal tumors. The most prevalent abnormality among 50 genes tested was the KRAS mutation, which was detected in 12/19 (63.2%) patients, followed by APC and TP53 mutations (47.4 and 36.8%, respectively). According to the tumor dysplasia grading of each component, KRAS mutations were found in 5/8 (62.5%) tumors with AC components, 6/9 (66.7%) tumors with HGD components, and 3/10 (30.0%) tumors with LGD components. TP53 mutations were found in 4/8 (50.0%) tumors with AC components, 3/9 (33.3%) tumors with HGD components, and 1/10 (10.0%) tumors with LGD components. APC mutations were found in 2/8 (25.0%) tumors with AC components, 6/9 (66.7%) tumors with HGD components, and 5/10 (50.0%) tumors with LGD components. Notably, an APC:T1556fs mutation was detected in six cases (31.6%), five of which were adenoma cases. Furthermore, STK11 mutations were confirmed in 2/8 (25.0%) AC cases and in 1/11 (9.1%) adenoma cases. CONCLUSION: APC:T1556fs and STK11 mutations found in duodenal adenomas/ACs highlight the importance of proteins encoded by these genes in tumor development. APC mutations were identified in duodenal adenomas more frequently than in duodenal ACs, which differed from the observations of typical adenoma-carcinoma sequences seen in colorectal cancer, suggesting the limited involvement of this mechanism in duodenal cancer development.

Adsorbate doping of MoS2 and WSe2: the influence of Na and Co.

We have investigated the influence of metal adsorbates (sodium and cobalt) on the occupied and unoccupied electronic structure of MoS2(0 0 0 1) and WSe2(0 0 0 1), through a combination of both photoemission and inverse photoemission. The electronic structure is rigidly shifted in both the WSe2 and MoS2 systems, with either Na or Co adsorption, generally as predicted by accompanying density functional theory based calculations. Na adsorption is found to behave as an electron donor (n-type) in MoS2, while Co adsorption acts as an electron acceptor (p-type) in WSe2. The n-type transition metal dichalcogenide (MoS2) is easily doped more n-type with Na deposition while the p-type transition metal dichalcogenide (WSe2) is easily doped more p-type with Co deposition. The binding energy shifts have some correlation with the work function differences between the metallic adlayer and the transition metal dichalcogenide substrate.

High-pressure rotational deformation apparatus to 135 GPa.

A large-strain, torsional deformation apparatus has been developed based on diamond anvil cells at high pressures, up to 135 GPa with a help of hard nano-polycrystalline diamond anvils. These pressure conditions correspond to the base of the Earth's mantle. An X-ray laminography technique is introduced for high-pressure in situ 3D observations of the strain markers. The technique developed in this study introduces the possibility of the in situ rheological measurements of the deep Earth materials under ultrahigh-pressure conditions.

The symmetry-resolved electronic structure of 2H-WSe2(0 0 0 1).

The orbital symmetry of the band structure of 2H-WSe2(0 0 0 1) has been investigated by means of angle-resolved photoelectron spectroscopy (ARPES) and density functional theory (DFT). The WSe2(0 0 0 1) experimental band structure is found, by ARPES, to be significantly different for states of even and odd reflection parities along both the [Formula: see text]-[Formula: see text] and [Formula: see text]-[Formula: see text] lines, in good agreement with results obtained from DFT. The light polarization dependence of the photoemission intensities from the top of the valence band for bulk WSe2(0 0 0 1) is explained by the dominance of W 5[Formula: see text] states around the [Formula: see text]-point and W 5d xy states around the [Formula: see text]-point, thus dominated, respectively, by states of even and odd symmetry, with respect to the [Formula: see text]-[Formula: see text] line. The splitting of the topmost valence band at [Formula: see text], due to spin-orbit coupling, is measured to be 0.49 ± 0.01 eV, in agreement with the 0.48 eV value from DFT, and prior measurements for the bulk single crystal WSe2(0 0 0 1), albeit slightly smaller than the 0.513 ± 0.01 eV observed for monolayer WSe2.

Symmetry-resolved surface-derived electronic structure of MoS2(0 0 0 1).

We find a wave vector dependence of the band symmetries for MoS(2)(0 0 0 1) in angle-resolved photoemission. The band structures are found to be significantly different for states of even and odd reflection parities, despite the absence of true mirror plane symmetry away from Γ, the Brillouin zone center, along the line to the K point, at the Brillouin zone edge. Our measurements agree with density functional theory (DFT) calculations for each band symmetry, with the notable exception of the Mo 4d(x(2)-y(2)) contributions to the valence band structure of MoS(2)(0 0 0 1). The band structure is indicative of strong S 3p and Mo 4d hybridization. In particular, the top of the valence band is predominantly composed of Mo 4d(3z(2)-r(2)) derived states near Γ, whereas near K Mo 4d(x(2)-y(2)) as well as Mo 4d(xy) dominate. In contrast, the bottom of the valence band is dominated by Mo 5s and S 3p(z) contributions.

CaCu3Pt4O12: the first perovskite with the B site fully occupied by Pt(4+).

A novel A-site ordered perovskite CaCu(3)Pt(4)O(12) was synthesized under high pressure and high temperature of 12 GPa and 1250 degrees C. CaCu(3)Pt(4)O(12) is the first perovskite in which the B site is fully occupied by Pt(4+). The crystal structure refinement based on the synchrotron powder X-ray diffraction data shows that CaCu(3)Pt(4)O(12) crystallizes in the space group Im3 (cubic) with a lattice constant of a = 7.48946(10) A. The magnetic susceptibility data show the antiferromagnetic transition at T(N) = 40 K, which is attributed to the magnetic ordering of Cu(2+) spins with S = 1/2.