Apoptosis-related factors are relevant to progression of pancreatic neuroendocrine tumors

BACKGROUND

Multidisciplinary therapy centered on antitumor drugs is indicated in patients with unresectable pancreatic neuroendocrine tumors (PanNET). However, the criteria for selection of optimal therapeutic agents is controversial. The aim of this study was to assess the malignancy of PanNET for optimal therapeutic drug selection.

METHODS

Forty-seven patients with PanNET who underwent surgery were reviewed retrospectively, and immunohistochemical characteristics, including expression of GLUT1, SSTR2a, SSTR5, Survivin, X-chromosome-linked inhibitor of apoptosis protein (XIAP), and Caspase3 in the resected specimens, were investigated. Relapse-free survival (RFS) and overall survival (OS) were evaluated with regard to the characteristics using the Kaplan-Meier method and compared with the log-rank test.

RESULTS

GLUT1 expression showed significant correlation with sex (p = 0.036) and mitotic rate (p = 0.048). Survivin and XIAP expression showed significant correlation with T-stage (p = 0.014 and 0.009), p-Stage (p = 0.028 and 0.045), and mitotic rate (p = 0.023 and 0.007). XIAP expression also significantly influenced OS (p = 0.044).

CONCLUSIONS

Survivin and XIAP correlated with grade of malignancy, and expression of XIAP in particular was associated with a poor prognosis. Expression of these proteins may be a useful indicator to select optimal therapeutic agents in PanNET.

Development of an artificial intelligence system for real-time intraoperative assessment of the Critical View of Safety in laparoscopic cholecystectomy

BACKGROUND

The Critical View of Safety (CVS) was proposed in 1995 to prevent bile duct injury during laparoscopic cholecystectomy (LC). The achievement of CVS was evaluated subjectively. This study aimed to develop an artificial intelligence (AI) system to evaluate CVS scores in LC.

MATERIALS AND METHODS

AI software was developed to evaluate the achievement of CVS using an algorithm for image classification based on a deep convolutional neural network. Short clips of hepatocystic triangle dissection were converted from 72 LC videos, and 23,793 images were labeled for training data. The learning models were examined using metrics commonly used in machine learning.

RESULTS

The mean values of precision, recall, F-measure, specificity, and overall accuracy for all the criteria of the best model were 0.971, 0.737, 0.832, 0.966, and 0.834, respectively. It took approximately 6 fps to obtain scores for a single image.

CONCLUSIONS

Using the AI system, we successfully evaluated the achievement of the CVS criteria using still images and videos of hepatocystic triangle dissection in LC. This encourages surgeons to be aware of CVS and is expected to improve surgical safety.

Appropriate indications for laparoscopic repeat hepatectomy

BACKGROUND

Laparoscopic repeat hepatectomy (LRH) has increased, but appropriate indications for LRH are unclear. This study aimed to clarify appropriate indications for LRH.

METHODS

We retrospectively compared surgical outcomes between open RH (ORH) (n = 57) and LRH (n = 40) groups. To detect difficult cases of complete pure LRH, we examined patients with unplanned intraoperative hand-assisted laparoscopic surgery (HALS)/open conversion (n = 6).

RESULTS

In the LRH versus ORH group, as previous hepatectomy, laparoscopic (75% vs. 12%, p < 0.001) and partial hepatectomy (Hr0) (73% vs. 37%, p = 0.002) were more frequently performed, and as RH procedure, partial hepatectomy (Hr0) (88% vs. 47%, p = 0.0002) was more frequently performed. S1 tumor cases were higher in ORH group (11% vs. 0%), but S2-6 cases were higher in LRH group (73% vs. 49%) (p = 0.02). In LRH group, compared to the pure LRH patients, HALS/open conversion patients underwent significantly more previous hepatectomy with more than lobectomy (Hr2-3) (33% vs. 2.9%, p = 0.033) and more RH procedures with segmentectomy (HrS) (33% vs. 2.9%, p = 0.03). All LRH requiring a repeat hepatic hilar approach were HALS conversions.

CONCLUSION

Appropriate indications for LRH were previous hepatectomy was laparoscopic partial hepatectomy (Hr0), and RH procedure was partial hepatectomy (Hr0) for S2-6 tumor location. When RH is more than segmentectomy (HrS) requiring a repeat hepatic hilar approach, planned HALS or ORH may be a better approach than pure LRH.

Impact of AI system on recognition for anatomical landmarks related to reducing bile duct injury during laparoscopic cholecystectomy

BACKGROUND

According to the National Clinical Database of Japan, the incidence of bile duct injury (BDI) during laparoscopic cholecystectomy has hovered around 0.4% for the last 10 years and has not declined. On the other hand, it has been found that about 60% of BDI occurrences are due to misidentifying anatomical landmarks. However, the authors developed an artificial intelligence (AI) system that gave intraoperative data to recognize the extrahepatic bile duct (EHBD), cystic duct (CD), inferior border of liver S4 (S4), and Rouviere sulcus (RS). The purpose of this research was to evaluate how the AI system affects landmark identification.

METHODS

We prepared a 20-s intraoperative video before the serosal incision of Calot's triangle dissection and created a short video with landmarks overwritten by AI. The landmarks were defined as landmark (LM)-EHBD, LM-CD, LM-RS, and LM-S4. Four beginners and four experts were recruited as subjects. After viewing a 20-s intraoperative video, subjects annotated the LM-EHBD and LM-CD. Then, a short video is shown with the AI overwriting landmark instructions; if there is a change in each perspective, the annotation is changed. The subjects answered a three-point scale questionnaire to clarify whether the AI teaching data advanced their confidence in verifying the LM-RS and LM-S4. Four external evaluation committee members investigated the clinical importance.

RESULTS

In 43 of 160 (26.9%) images, the subjects transformed their annotations. Annotation changes were primarily observed in the gallbladder line of the LM-EHBD and LM-CD, and 70% of these shifts were considered safer changes. The AI-based teaching data encouraged both beginners and experts to affirm the LM-RS and LM-S4.

CONCLUSION

The AI system provided significant awareness to beginners and experts and prompted them to identify anatomical landmarks linked to reducing BDI.

Technical and oncological safety of pancreatectomy for pancreatic cancer in older adults aged over 75 years versus younger adults: A single-center retrospective cohort study

AIM

The number of surgeries for pancreatic ductal adenocarcinoma (PDAC) in older adults has been rising. This study aimed to evaluate the technical and oncological safety of pancreatectomy for older adults aged ≥75 years with PDAC by retrospectively comparing their short- and long-term outcomes with those of younger adults aged <75 years.

METHODS

Data were collected from 117 patients who underwent pancreatectomy for PDAC in our department. The indication for surgery regarding patient characteristics was considered according to each patient's American Society of Anesthesiologists physical status and Eastern Cooperative Oncology Group Performance Status Scale. Data of older adults (n = 32) were compared with those of younger adults (n = 85), and comprised patient background, surgical factors, postoperative course, histopathological factors and prognostic factors. Additionally, prognostic nutritional index values preoperatively and at 1 and 6 months postoperatively were compared between the two groups.

RESULTS

Although American Society of Anesthesiologists physical status and comorbidities were worse in older adults, there were no significant differences in surgical factors, postoperative courses and histopathological factors between the two groups. The overall complication rate tended to be higher in older adults (40.6%) than in younger adults (29.4%). There were no differences in median lengths of recurrence-free survival and overall survival (older adults vs younger adults: 12 vs 13 months, P = 0.545, and 26 vs 20 months, P = 0.535, respectively) between the two groups. Furthermore, no significant differences were found in prognostic nutritional index preoperatively to 6 months after surgery.

CONCLUSION

With careful determination of surgical indications, pancreatectomy for PDAC can be carried out with acceptable post-pancreatectomy morbidity in younger adults. Geriatr Gerontol Int 2023; ••: ••-••.

Glucose metabolic upregulation via phosphorylation of S6 ribosomal protein affects tumor progression in distal cholangiocarcinoma

BACKGROUND

The prognosis of distal cholangiocarcinoma (dCCA) remains poor; thus, the identification of new therapeutic targets is warranted. Phosphorylated S6 ribosomal protein indicates a mammalian target of rapamycin complex 1 (mTORC1) activity, and mTORC1 plays a central role in controlling cell growth and regulating glucose metabolism. We aimed to clarify the effect of S6 phosphorylation on tumor progression and the glucose metabolic pathway in dCCA.

METHODS

Thirty-nine patients with dCCA who underwent curative resection were enrolled in this study. S6 phosphorylation and the expression of GLUT1 were evaluated by immunohistochemistry, and their relationship with clinical factors was investigated. The effect of S6 phosphorylation on glucose metabolism with PF-04691502 treatment, an inhibitor of S6 phosphorylation, was examined in cancer cell lines by Western blotting and metabolomics analysis. Cell proliferation assays were performed with PF-04691502.

RESULTS

S6 phosphorylation and the expression of GLUT1 were significantly higher in patients with an advanced pathological stage. Significant correlations between GLUT1 expression, S6 phosphorylation, and SUV-max of FDG-PET were shown. In addition, cell lines with high S6 phosphorylation levels showed high GLUT1 levels, and the inhibition of S6 phosphorylation reduced the expression of GLUT1 on Western blotting. Metabolic analysis revealed that inhibition of S6 phosphorylation suppressed pathways of glycolysis and the TCA cycle in cell lines, and then, cell proliferation was effectively reduced by PF-04691502.

CONCLUSION

Upregulation of glucose metabolism via phosphorylation of S6 ribosomal protein appeared to play a role in tumor progression in dCCA. mTORC1 may be a therapeutic target for dCCA.

Development of a cross-artificial intelligence system for identifying intraoperative anatomical landmarks and surgical phases during laparoscopic cholecystectomy

BACKGROUND

Attention to anatomical landmarks in the appropriate surgical phase is important to prevent bile duct injury (BDI) during laparoscopic cholecystectomy (LC). Therefore, we created a cross-AI system that works with two different AI algorithms simultaneously, landmark detection and phase recognition. We assessed whether landmark detection was activated in the appropriate phase by phase recognition during LC and the potential contribution of the cross-AI system in preventing BDI through a clinical feasibility study (J-SUMMIT-C-02).

METHODS

A prototype was designed to display landmarks during the preparation phase and Calot's triangle dissection. A prospective clinical feasibility study using the cross-AI system was performed in 20 LC cases. The primary endpoint of this study was the appropriateness of the detection timing of landmarks, which was assessed by an external evaluation committee (EEC). The secondary endpoint was the correctness of landmark detection and the contribution of cross-AI in preventing BDI, which were assessed based on the annotation and 4-point rubric questionnaire.

RESULTS

Cross-AI-detected landmarks in 92% of the phases where the EEC considered landmarks necessary. In the questionnaire, each landmark detected by AI had high accuracy, especially the landmarks of the common bile duct and cystic duct, which were assessed at 3.78 and 3.67, respectively. In addition, the contribution to preventing BDI was relatively high at 3.65.

CONCLUSIONS

The cross-AI system provided landmark detection at appropriate situations. The surgeons who previewed the model suggested that the landmark information provided by the cross-AI system may be effective in preventing BDI. Therefore, it is suggested that our system could help prevent BDI in practice. Trial registration University Hospital Medical Information Network Research Center Clinical Trial Registration System (UMIN000045731).

An intraoperative artificial intelligence system identifying anatomical landmarks for laparoscopic cholecystectomy: a prospective clinical feasibility trial (J-SUMMIT-C-01)

BACKGROUND

We have implemented Smart Endoscopic Surgery (SES), a surgical system that uses artificial intelligence (AI) to detect the anatomical landmarks that expert surgeons base on to perform certain surgical maneuvers. No report has verified the use of AI-based support systems for surgery in clinical practice, and no evaluation method has been established. To evaluate the detection performance of SES, we have developed and established a new evaluation method by conducting a clinical feasibility trial.

METHODS

A single-center prospective clinical feasibility trial was conducted on 10 cases of LC performed at Oita University hospital. Subsequently, an external evaluation committee (EEC) evaluated the AI detection accuracy for each landmark using five-grade rubric evaluation and DICE coefficient. We defined LM-CBD as the expert surgeon's "judge" of the cystic bile duct in endoscopic images.

RESULTS

The average detection accuracy on the rubric by the EEC was 4.2 ± 0.8 for the LM-CBD. The DICE coefficient between the AI detection area of the LM-CBD and the EEC members' evaluation was similar to the mean value of the DICE coefficient between the EEC members. The DICE coefficient was high score for the case that was highly evaluated by the EEC on a five-grade scale.

CONCLUSION

This is the first feasible clinical trial of an AI system designed for intraoperative use and to evaluate the AI system using an EEC. In the future, this concept of evaluation for the AI system would contribute to the development of new AI navigation systems for surgery.

Pancreas-preserving partial duodenectomy for non-ampullary duodenal neoplasms: three case reports

Background

There are multiple surgical procedures for resecting non-ampullary duodenal neoplasms (NADNs), and the appropriate method is selected depending on the tumor location and diagnosis. We herein report 3 cases of NADNs that were resected using pancreas-preserving partial duodenectomy (PPD).

Case reports

The first patient, a 73-year-old woman with a circumferential duodenal adenoma in the supra-ampullary duodenum, underwent surgery. After laparotomy, the duodenum proximal to the tumor was confirmed using intraoperative endoscopy and dissected. The duodenum distal to the tumor was dissected under direct visualization, and the specimen was removed. The distal stump of the duodenum was closed, and duodenojejunostomy was performed as described by Billroth II. The tumor was diagnosed as an adenoma 75 mm in size. She was discharged 12 days after surgery without any complications. The second patient, a 48-year-old man, was diagnosed with a neuroendocrine neoplasm (NEN) with a diameter of 14 mm in the supra-ampullary duodenum. Laparoscopic PPD was performed. He was diagnosed with NEN G1 and discharged the 11th day after surgery. The third patient, a 71-year-old man with a 0–Is + IIa lesion in the horizontal duodenum, underwent surgery. After laparotomy, the horizontal duodenum and proximal jejunum were resected, and duodenojejunostomy was performed. The patient was diagnosed with stage I adenocarcinoma and discharged on the 15th day after surgery.

Conclusion

PPD is useful for avoiding the morbidity of pancreatoduodenectomy in the management of NADNs without invasion to the ampulla of Vater or pancreas.

An additional port in difficult laparoscopic cholecystectomy for surgical safety

BACKGROUND

Tokyo Guidelines 2018, clinical practice guidelines for acute cholangitis and cholecystitis, recommend bailout procedures to prevent bile duct injury (BDI) during laparoscopic cholecystectomy (LC) for difficult gallbladder. We first insert an additional port (AP) for difficult gallbladder that may require bailout procedures. Because the usefulness of an AP during LC is unclear, we therefore examined the efficacy of the AP during LC in this study.

METHODS

Data were collected from 115 patients who underwent LC for acute cholecystitis in our department. The indications for AP were excessive bleeding, scarring, and poor visual field around Calot's triangle. AP was inserted into the right middle abdomen so as not to interfere with other trocars and was used by the assistant. Surgical outcomes were evaluated based on AP use during LC.

RESULTS

AP was inserted in 19 patients during LC (AP group). The indications for AP were excessive bleeding in nine patients, scarring around Calot's triangle in seven patients, and poor visual field around Calot's triangle in three patients. Open conversion was performed in two patients in the non-AP group. BDI occurred in one patient in the non-AP group. In patients with Difficulty Score 3, operation time was significantly shorter (P = .038) and Critical View of Safety (CVS) score was significantly higher in the AP group (P = .046).

CONCLUSION

AP is useful in patients with excessive bleeding to shorten operation time and increase the CVS score. AP may be one useful option for difficult gallbladder.

Artificial intelligence software available for medical devices: surgical phase recognition in laparoscopic cholecystectomy

Background

Surgical process modeling automatically identifies surgical phases, and further improvement in recognition accuracy is expected with deep learning. Surgical tool or time series information has been used to improve the recognition accuracy of a model. However, it is difficult to collect this information continuously intraoperatively. The present study aimed to develop a deep convolution neural network (CNN) model that correctly identifies the surgical phase during laparoscopic cholecystectomy (LC).

Methods

We divided LC into six surgical phases (P1–P6) and one redundant phase (P0). We prepared 115 LC videos and converted them to image frames at 3 fps. Three experienced doctors labeled the surgical phases in all image frames. Our deep CNN model was trained with 106 of the 115 annotation datasets and was evaluated with the remaining datasets. By depending on both the prediction probability and frequency for a certain period, we aimed for highly accurate surgical phase recognition in the operation room.

Results

Nine full LC videos were converted into image frames and were fed to our deep CNN model. The average accuracy, precision, and recall were 0.970, 0.855, and 0.863, respectively.

Conclusion

The deep learning CNN model in this study successfully identified both the six surgical phases and the redundant phase, P0, which may increase the versatility of the surgical process recognition model for clinical use. We believe that this model can be used in artificial intelligence for medical devices. The degree of recognition accuracy is expected to improve with developments in advanced deep learning algorithms.

Gastric Wall Thickness and Linear Staple Height in Sleeve Gastrectomy in Japanese Patients with Obesity

BACKGROUND

Laparoscopic sleeve gastrectomy (LSG) is a standard procedure due to its low complication rates and favorable outcomes. However, limited data are available regarding the optimal size of linear staplers in relation to gastric wall thickness (GWT).

METHODS

Between August 2016 and December 2020, we performed LSG in 70 patients with an average age, body weight, and body mass index of 42 years, 107 kg, and 40 kg/m², respectively. We measured the GWT at the antrum, body, and fundus using resected specimens. We used an endo-linear stapler, and the closed staple height (CSH) was 1.75 mm.

RESULTS

We found that the average GWT at the antrum was significantly thicker than the GWT at the body and fundus. There was a statistically significant relationship between body weight and the GWT at the antrum and body and obstructive sleep apnea and the GWT at the body. The average CSH/GWT ratios were 0.55, 0.62, and 0.90 at the antrum, body, and fundus, respectively. However, in 20 patients (29%), the CSH/GWT ratio at the fundus area was ≥ 1.0, and only preoperative body weight was a significant predictor for a CSH/GWT ratio of ≥ 1.0.

CONCLUSION

A light body weight may be related to a CSH/GWT ratio of ≥ 1.0 at the fundus.

Predictors of early withdrawal from follow-up visits after laparoscopic sleeve gastrectomy in a Japanese institution

PURPOSE

Postoperative weight loss is related to postoperative adherence to follow-up after bariatric/metabolic surgery, but many patients stop attending follow-up visits early. The aim of this study was to clarify predictors of early withdrawal from follow-up after laparoscopic sleeve gastrectomy (LSG) in a Japanese institution.

METHODS

One hundred and fifty-three patients who underwent LSG were retrospectively included in this study. Multivariate analysis was performed to evaluate independent predictors of withdrawal from follow-up visits within 12 months after LSG among significant or nearly significant factors in the univariate analyses. The discrimination power of significant factors was estimated using area under the receiver operating characteristic curve (AUC).

RESULTS

Within 12 months after LSG, 25 of the 153 patients withdrew from follow-up visits. The multivariate analysis showed that age was the only significant predictor of withdrawal. The AUC for age was 0.685, and the cut-off value was < 40 years. The younger patients (< 40 years old) had a significantly higher rate of withdrawal compared with the older patients (≥ 40 years) (27.0% vs. 8.9%).

CONCLUSION

Older Japanese patients (≥ 40 years old) may be better candidates for LSG. We consider it significant to continue to emphasize the importance of follow-up visits in younger patients after LSG.

Interplay of spin-orbit coupling and Coulomb interaction in ZnO-based electron system

Spin-orbit coupling (SOC) is pivotal for various fundamental spin-dependent phenomena in solids and their technological applications. In semiconductors, these phenomena have been so far studied in relatively weak electron-electron interaction regimes, where the single electron picture holds. However, SOC can profoundly compete against Coulomb interaction, which could lead to the emergence of unconventional electronic phases. Since SOC depends on the electric field in the crystal including contributions of itinerant electrons, electron-electron interactions can modify this coupling. Here we demonstrate the emergence of the SOC effect in a high-mobility two-dimensional electron system in a simple band structure MgZnO/ZnO semiconductor. This electron system also features strong electron-electron interaction effects. By changing the carrier density with Mg-content, we tune the SOC strength and achieve its interplay with electron-electron interaction. These systems pave a way to emergent spintronic phenomena in strong electron correlation regimes and to the formation of quasiparticles with the electron spin strongly coupled to the density.

[Long‒Term Survival after Lung Resection for Lung Metastasis of Pancreatic Cancer-A Report of Two Cases]

Some reports have shown that the prognosis of recurrent lung metastases after resection of pancreatic cancer is better than that for other organs. We report on 2 cases of long‒term survival after lung resection for lung metastases from pancreatic cancer. Case 1: A 73‒year‒old man underwent distal pancreatectomy for pancreatic body cancer. Adjuvant chemotherapy of S‒1 was administered for 6 months. At 3 years after surgery, 2 small metastatic nodules were detected in the right lung, and the patient underwent thoracoscopic right upper lobectomy. At 5 years and 9 months after the initial surgery, he is alive without recurrence. Case 2: An 81‒year‒old woman underwent pylorus‒preserving pancreatoduodenectomy for pancreatic head cancer. Adjuvant chemotherapy of S‒1 was administered for 4 months. At 1 year and 9 months after surgery, a metastatic nodule was detected in the left upper lung, and the patient underwent thoracoscopic left upper lobectomy. At 4 years and 6 months after initial surgery, radiation therapy was performed for localized bone metastasis. At 5 years and 1 month after the initial surgery, she is alive without other recurrences. In conclusion, recurrent lung metastases of pancreatic cancer with a small number of metastases may result in long‒term survival following resection.

Liquid/solution-based microfluidic quantum dots light-emitting diodes for high-colour-purity light emission

Organic light-emitting diodes (OLEDs) using a liquid organic semiconductor (LOS) are expected to provide extremely flexible displays. Recently, microfluidic OLEDs were developed to integrate and control a LOS in a device combined with microfluidic technology. However, LOS-based OLEDs show poor-colour-purity light emissions owing to their wide full width at half maximum (FWHM). Here we report liquid/solution-based microfluidic quantum dots light-emitting diodes (QLEDs) for high-colour-purity light emission. Microfluidic QLEDs contain liquid materials of LOS for a backlight and QDs solutions as luminophores. The microfluidic QLED exhibits red, green, and blue light emissions and achieves the highest light colour purity ever reported among LOS-based devices for green and red lights with narrow FWHMs of 26.2 nm and 25.0 nm, respectively. Additionally, the effect of the channel depth for the luminophore on the peak wavelength and FWHM is revealed. The developed device extends the capabilities of flexible microfluidic OLEDs-based and QDs-based displays.

Clinical Significance of Splenic Vessels and Anatomical Features in Laparoscopic Splenectomy

Introduction: Laparoscopic splenectomy (LS) has become the standard treatment for benign hematological disorders and hypersplenism. However, serious complications such as pancreatic fistula and portal venous thrombosis (PVT) sometimes occur. We investigated the clinical significance of splenic vessels and anatomical features in LS. Methods: Patient data were collected from 32 patients who underwent LS. The indications for LS were hypersplenism due to liver cirrhosis, idiopathic thrombocytopenic purpura, hereditary spherocytosis, and others. Close contact of pancreatic tail with splenic hilum, spleen volume, and diameters of splenic vessels were evaluated on computed tomography images. Results: Close contact of pancreatic tail with splenic hilum was recognized in 15 of the patients. The close contact was significantly associated with operation time (P = .038), spleen volume (P = .021), and spleen volume/body surface area (BSA) ratio (P = .001). In multivariate analysis, spleen volume/BSA ratio was an independent factor for close contact (P = .022). PVT occurred in 3 cirrhosis patients, and the diameter of the splenic vein (SV) was significantly associated with PVT as a result of multivariate analysis (P = .027). Conclusion: Close contact of the pancreatic tail with the splenic hilum may cause a longer operation time at LS and be associated with spleen volume/BSA ratio. A larger SV diameter in cirrhosis patients may be related to PVT after LS.

Large Variation of Dirac Semimetal State in Perovskite CaIrO_{3} with Pressure-Tuning of Electron Correlation

The impact of electron correlation on the Dirac semimetal state is investigated for perovskite CaIrO_{3} in terms of the magnetotransport properties under varying pressures. The reduction of electron correlation with a pressure of 1 GPa enhances the Fermi velocity as much as 40%, but it reduces the mobility by an order of magnitude by detuning the Dirac node from the Fermi energy. Moreover, the giant magnetoresistance at the quantum limit due to the one-dimensional confinement of Dirac electrons is critically suppressed under pressure. These results indicate that the electron correlation is a crucial knob for controlling the transport of a correlated Dirac semimetal.

P977Selective liner ablation according to the type of tachycardia induced after pulmonary vein isolation in single-procedure for long-standing persistent atrial fibrillation

Background

The most effective approach for long-standing persistent atrial fibrillation (LSPAF) ablation remained undetermined. Here, we hypothesized that selective linear ablation (SLA) according to the type of tachycardia induced by burst atrial pacing (BAP) after pulmonary venous isolation (PVI) in single-procedure reduces the recurrence.

Methods

A cohort of 66 LSPAF patients (Mean age 71.0±8.2 years, AF duration 40.5±58.8 months) who underwent PVI in single-procedure between April 2016 and November 2018 was evaluated.

Results

Any sustained atrial tachycardia (AT) or AF were not inducible by BAP after PVI in 21 patients (Non-inducible group, 31.8%, 71.3±7.9 years, 34.4±54.2 months). These patients underwent cavo-tricuspid isthmus (CTI) ablation after PVI. Forty-one patients underwent selective liner ablation according to the type of tachycardia induced by BAP after PVI (SLA group, 62.1%, 71.2±8.3 years, 39.3±55.6 months). Maccroreentry ATs (6 common atrial flutter, 5 AT originating from left atrial anterior wall, 2 peri-mitral atrial flutter, 1 roof-dependent atrial flutter) were induced by BAP in 14 patients of SLA group (73.2±19.7 years, 51.7±83.5 months). RF applications created the complete linear lesions to terminate maccroreentry ATs. Sustained AF was induced by BAP after PVI in 27 patients of SLA group (70.2±9.2 years, 32.9±31.2 months). These patients underwent posterior wall isolation (PWI) and CTI ablation. Unmappable AT was induced by BAP after PVI in 4 patients (Non-SLA group, 6.1%, 67.0±9.7 years, 84.5±105.6 months). These patients underwent PWI, CTI and mitral isthmus ablation on an empirical basis instead of SLA. Using a 90-day blanking period, the single-procedure Kaplan-Meier estimates of AT or AF event-free survival were 79% at 12 months. During follow-up (14.5±8.0 months), although 19 /21 (90.5%) of Non-inducible group patients and 33/41 (80.5%) of SLA group patients did not experience AT or AF recurrence, all of Non-SLA group patients experienced AF recurrence. There was no difference between Non-inducible group and SLA group in predicting recurrence of AT or AF (p=0.3). However, there was a difference when compared with Non-SLA group (each p<0.001). Non-SLA group was an independent powerful predictor resulting in recurrence of AF after adjusting for potential confounding factors (adjusted hazard ratio = 7.17; 95% confidence interval; 2.2–23.1, p=0.001, Wald χ2=10.9). Furthermore, in Kaplan-Meier survival curves for predicting AT or AF recurrence, Non-SLA group was the significant predictive marker of AT or AF recurrence (Log-Lank χ2=18.0, p<0.001).

Kaplan-Meier survival curves

Conclusions

In LSPAF patients without inducibility of any tachycardia after PVI, sinus rhythm was highly maintained without stepwise ablation other than CTI ablation. SLA reduced recurrence of AF in LSPAF patients with AT and AF induced after PVI. In addition, nonselective liner ablations for unmappable AT after PVI were less effective in LSPAF patients.

P5697J-wave elevation in the inferior leads is a predictor of lethal ventricular arrhythmia initiated by premature ventricular contractions with right bundle branch block and superior axis

Background

Lethal-ventricular-arrhythmia (VA) could be sometimes initiated by idiopathic Premature Ventricular Contractions (PVCs) originated form inferior wall. Furthermore, J-wave elevation in inferior leads was sometimes associated with lethal-VA. However, it was unclear the relationship between these PVCs and J-wave elevation in patients with lethal-VA.

Purpose

The aim of this study was to investigate the relationship between PVCs and J-wave elevation.

Methods and results

We studied 32 patients who underwent radiofrequency (RF) ablation of idiopathic PVCs with RBBB and superior axis. These PVCs were originating from inferior wall of left ventricular. Lethal-VA was defined as ventricular fibrillation (VF) or ventricular tachycardia (VT) with loss of consciousness (LOC). Among 32 patients, 3 had VF and 2 had VT with LOC. Other 27 had non-lethal-VA. Baseline clinical characteristics were not significantly difference between lethal and non-lethal-VA. The ratio of J-wave elevation in lethal-VA was significant higher as compared to those with non-lethal-VA (5/5 (100%) vs. 3/27 (11.1%), p<0.0001). Furthermore, no patients had recurrence of lethal-VA with J wave elevation in inferior leads after RF ablation of these PVCs with RBBB and superior axis,

Conclusions

We speculated that J-wave elevation in inferior leads might be a predictor of lethal-VA initiated by PVCs with RBBB and superior axis. RF ablation of these PVCs were useful method of treating lethal-VA.

Acknowledgement/Funding

None

Strong-correlation induced high-mobility electrons in Dirac semimetal of perovskite oxide

Electrons in conventional metals become less mobile under the influence of electron correlation. Contrary to this empirical knowledge, we report here that electrons with the highest mobility ever found in known bulk oxide semiconductors emerge in the strong-correlation regime of the Dirac semimetal of perovskite CaIrO₃. The transport measurements reveal that the high mobility exceeding 60,000 cm²V⁻¹s⁻¹ originates from the proximity of the Fermi energy to the Dirac node (ΔE < 10 meV). The calculation based on the density functional theory and the dynamical mean field theory reveals that the energy difference becomes smaller as the system approaches the Mott transition, highlighting a crucial role of correlation effects cooperating with the spin-orbit coupling. The correlation-induced self-tuning of Dirac node enables the quantum limit at a modest magnetic field with a giant magnetoresistance, thus providing an ideal platform to study the novel phenomena of correlated Dirac electron.

Electron correlation normally makes electrons less mobile, but it is still not clear when correlation becomes very strong in Dirac semimetals. Here, Fujioka et al. report a very high electron mobility exceeding 60,000 cm²V⁻¹s⁻¹ in correlated Dirac semimetal of perovskite CaIrO3, due to the enhanced electron correlation nearby the Mott transition.

Comparison of Sensitivity of Immunocomplex Capture Fluorescence Analysis for Detecting Donor-specific Anti-HLA Class II Antibodies in Kidney Transplant Patients

BACKGROUND

Immunocomplex capture fluorescence analysis (ICFA) detects donor-specific antihuman leukocyte antigen (HLA) antibodies (DSA), but the detection sensitivity of HLA class II antibodies using conventional ICFA is as low as 57%. The aim of the study was to improve the detection sensitivity of HLA class II antibodies by ICFA, and compare the ICFA results with the Luminex single-antigen bead test.

METHODS

Six DSA-negative kidney transplant donors and recipient pairs and 10 HLA class II DSA-positive pairs were included in the study. The detection sensitivity of modified ICFA was compared with conventional ICFA, and the ICFA results were compared with the Luminex single-antigen bead test.

RESULTS

The index value of modified ICFA was higher than that of conventional ICFA. The cutoff value of conventional ICFA was 30,686 (MFI), which was improved to 19,405 using modified ICFA. Regarding the HLA-DQ antibody, 5 samples found to be positive by Luminex single-antigen bead testing were all negative using modified ICFA. The reason for this discrepancy could be related to: (1) the difference in detection sensitivity; (2) the difference in HLA antigen surface expression between naive lymphocytes and synthetic beads; or (3) the structure of synthetic HLA DQ antigen on the Luminex single-antigen beads.

CONCLUSION

The index value of the modified ICFA was higher than that of conventional ICFA, and the detection sensitivity of HLA class II antibodies was improved by modified ICFA. Further assessment is necessary to clarify the reasons for divergence between ICFA and Luminex single-antigen bead test results.

Advanced capabilities for materials modelling with Quantum ESPRESSO

Quantum EXPRESSO is an integrated suite of open-source computer codes for quantum simulations of materials using state-of-the-art electronic-structure techniques, based on density-functional theory, density-functional perturbation theory, and many-body perturbation theory, within the plane-wave pseudopotential and projector-augmented-wave approaches. Quantum EXPRESSO owes its popularity to the wide variety of properties and processes it allows to simulate, to its performance on an increasingly broad array of hardware architectures, and to a community of researchers that rely on its capabilities as a core open-source development platform to implement their ideas. In this paper we describe recent extensions and improvements, covering new methodologies and property calculators, improved parallelization, code modularization, and extended interoperability both within the distribution and with external software.