Preoperative Therapy for Unresectable Locally Advanced Pancreatic Cancer for ≥6 Months Improves Prognosis After Pancreatectomy

BACKGROUND/AIM

This study aimed to identify the optimal duration of pretreatment for unresectable locally advanced (UR-LA) pancreatic cancer and analyze its effect on the prognosis.

PATIENTS AND METHODS

This retrospective study included 39 patients with UR-LA pancreatic cancer after pancreatectomy. The cutoff period of preoperative therapy was determined using a receiver operating characteristic curve. We investigated the relationship between preoperative and intraoperative clinical variables and overall survival (OS) in univariate and multivariate analyses. The relationship between the preoperative therapy duration and the clinicopathological variables was investigated. OS was compared according to preoperative therapy duration and the presence or absence of adjuvant surgery.

RESULTS

After pretreatment, 15 patients underwent adjuvant surgery and 24 patients continued on chemotherapy without surgery. The multivariate analysis demonstrated preoperative therapy duration ≥6 months was an independent prognostic factor [hazard ratio (HR)=0.10, p=0.04]. No significant difference in the clinicopathological variables was observed between the two groups according to preoperative therapy duration. The OS was significantly better in patients who underwent adjuvant surgery after preoperative therapy duration ≥6 months than in those after preoperative therapy duration <6 months and in those without adjuvant surgery (5-year OS rates: 80% vs. 0%; p=0.01 and 5-year OS rates: 80% vs. 0%; p=0.004, respectively). The OS was not significantly better in patients with adjuvant surgery after preoperative therapy duration <6 months than in those without adjuvant surgery (2-year OS rates: 45.7% vs. 38.1%; p=0.98).

CONCLUSION

Preoperative therapy for UR-LA pancreatic cancer for ≥6 months is necessary to improve prognosis after adjuvant surgery.

A Novel Observational Strategy for Nonfunctional Pancreatic Neuroendocrine Neoplasms With Texture Analysis: A Multicenter Retrospective Study

Background/Aim

Surgical resection is recommended for nonfunctional pancreatic neuroendocrine neoplasms (NF-pNENs). However, metastasis is rare in patients with small lesions with histological grade 1 (G1); thus, observation is an optional treatment approach for small NF-pNENs. Texture analysis (TA) is an imaging analysis mode for quantification of heterogeneity by extracting quantitative parameters from images. We retrospectively evaluated the utility of TA in predicting histological grade of resected NF-pNENs in a multicenter retrospective study.

Patients and Methods

The utility of TA in preoperative prediction of grade were evaluated with 29 patients treated by pancreatectomy for NF-pNEN who underwent preoperative dynamic computed tomography scan between January 1, 2013 and December 31, 2020 at three hospitals affiliated with the Jikei University School of Medicine. TA was performed with dedicated software for medical imaging processing for determining histological tumor grade using dynamic computed tomography images.

Results

Histological tumor grades based on the 2017 World Health Organization Classification for Pancreatic Neuroendocrine Neoplasms were grade 1, 2 and 3 in 18, 10 and one patient, respectively. Preoperative grades by TA were 1 and 2/3 in 15 and 14 patients, respectively. The sensitivity, specificity and area under the curve for TA-oriented grade 1 lesions were 1.00, 0.889 and 0.965 (95% confidence interval=0.901-1.000), respectively.

Conclusion

TA is useful for predicting grade 2/3 NF-pNEN and can provide a safe option for observation for patients with small grade 1 lesions.

Dynamics of the prognostic nutritional index in preoperative chemotherapy in patients with colorectal liver metastases

BACKGROUND

Identifying the prognostic indicators that reflect the efficacy of preoperative chemotherapy is necessary. In this study, we investigated the prognostic indicators targeting the systemic inflammatory response for the administration of preoperative chemotherapy in patients with colorectal liver metastases.

METHODS

Data for 192 patients were retrospectively analyzed. The relationship between overall survival and clinicopathological variables, including biomarkers such as the prognostic nutritional index, was investigated in patients who underwent upfront surgery or preoperative chemotherapy.

RESULTS

In the upfront surgery group, extrahepatic lesion (p=0.01) and low prognostic nutritional index (p < 0.01) were significant prognostic indicators, whereas a decrease in the prognostic nutritional index (p=0.01) during preoperative chemotherapy were independent poor prognostic factors in the preoperative chemotherapy group. In particular, a decrease in the prognostic nutritional index was a significant prognostic marker in patients aged <75 years (p=0.04). In patients with a low prognostic nutritional index aged <75 years, preoperative chemotherapy significantly prolonged overall survival (p=0.02).

CONCLUSION

A decrease in the prognostic nutritional index during preoperative chemotherapy predicted overall survival of patients with colorectal liver metastases after hepatic resection, and preoperative chemotherapy may be effective for patients aged <75 years with a low prognostic nutritional index.

A Multidisciplinary Treatment Strategy With Conversion Surgery for Hepatocellular Carcinoma

BACKGROUND/AIM

Sorafenib was previously the only targeted therapy for hepatocellular carcinoma (HCC). However, pharmaceutical therapy for HCC has undergone remarkable advances in recent years. Herein, we report cases of unresectable advanced HCC responding to pharmaceutical therapy resulting in improved prognosis through surgical intervention.

PATIENTS AND METHODS

Five patients with intermediate and advanced stage HCC treated with lenvatinib followed by hepatectomy between October 2019 and September 2022 were retrospectively reviewed. Patient characteristics, tumor factors, and treatment factors were compared.

RESULTS

The median patient age was 66 (60-79) years, and all patients (100%) were male. The median follow-up period was 10.4 months. All five patients received lenvatinib treatment for more than 2 months before surgery. Three patients achieved partial responses and 2 patients had stable disease with modified RESIST in response to lenvatinib. Three patients had a partial pathological response (50% or more tumor necrosis). Four patients underwent R0 resection and 3 cases had no recurrence.

CONCLUSION

Lenvatinib might be useful for intermediate and advanced HCC and long-term survival may be obtained by combining lenvatinib therapy with surgery.

D1 Distal Pancreatectomy for Left-sided Pancreatic Ductal Adenocarcinoma Is Justifiable: A Propensity-score Matched Multicenter Study

BACKGROUND/AIM

Evidence on the optimal extent of lymph node dissection for left-sided pancreatic ductal adenocarcinoma (PDAC) is scarce. The aim of the current study was to compare the long-term outcomes of patients who underwent D1 distal pancreatectomy (DP) with D2 DP for left-sided PDAC.

PATIENTS AND METHODS

Patients undergoing DP for left-sided PDAC at the four institutions affiliated to The Jikei University were enrolled in this study. Patients were divided into D1 and D2 groups. Patients' clinical characteristics, overall survival (OS), and relapse-free survival (RFS) were compared between the two groups before and after propensity-score matched (PSM) analysis.

RESULTS

Of 145 patients with left-sided PDAC, 55 patients underwent D1 DP and 90 underwent D2 DP, of whom 38 matched pairs were included in the PSM analytic cohort. In the unmatched cohort, no significant difference was found between the D1 and D2 groups for both OS (median 2.51 vs. 3.07 years; p=0.709) and RFS (median 1.47 vs. 1.27 years; p=0.565). After PSM, OS (median 2.37 vs. 3.56 years; p=0.407) and RFS (median 1.35 vs. 1.11 years; p=0.542) were not significantly different between the two groups. In a comparison of regional and systemic recurrence sites, no significant difference was observed between the two groups (p=0.500).

CONCLUSION

The long-term survival of D1 DP for left-sided PDAC was not inferior to D2 DP. In an era in which the importance of multidisciplinary treatment for PDAC has been documented, unnecessary extended surgery should be avoided.

Increased Ion Temperature and Neutron Yield Observed in Magnetized Indirectly Driven D_{2}-Filled Capsule Implosions on the National Ignition Facility

The application of an external 26 Tesla axial magnetic field to a D_{2} gas-filled capsule indirectly driven on the National Ignition Facility is observed to increase the ion temperature by 40% and the neutron yield by a factor of 3.2 in a hot spot with areal density and temperature approaching what is required for fusion ignition [1]. The improvements are determined from energy spectral measurements of the 2.45 MeV neutrons from the D(d,n)^{3}He reaction, and the compressed central core B field is estimated to be ∼4.9  kT using the 14.1 MeV secondary neutrons from the D(T,n)^{4}He reactions. The experiments use a 30 kV pulsed-power system to deliver a ∼3  μs current pulse to a solenoidal coil wrapped around a novel high-electrical-resistivity AuTa_{4} hohlraum. Radiation magnetohydrodynamic simulations are consistent with the experiment.

Dysbiosis of the Fecal and Biliary Microbiota in Biliary Tract Cancer

Characteristic bile duct and gut microbiota have been identified in patients with chronic biliary tract disease. This study aimed to characterize the fecal and bile microbiota in biliary tract cancer (BTC) patients and their relationship. Patients with BTC (n = 30) and benign biliary disease (BBD) without cholangitis (n = 11) were included. Ten healthy, age-matched subjects were also recruited for fecal microbiota comparison. The fecal and bile duct microbiotas were analyzed by sequencing the 16S rRNA gene V3-V4 region. Live bacteria were obtained in the bile from three BTC patients by culture, and metagenomics-based identification was performed. Linear discriminant analysis effect size showed a higher Enterobacteriaceae abundance and a lower Clostridia abundance, including that of Faecalibacterium and Coprococcus, in the BTC patients than in the other subjects. Ten of 17 operational taxonomic units (OTUs) assigned to Enterobacteriaceae in the bile were matched with the OTUs found in the BTC subject fecal samples. Furthermore, a bile-isolated strain possessed the carcinogenic bacterial colipolyketide synthase-encoding gene. Enterobacteriaceae was enriched in the BTC feces, and more than half of Enterobacteriaceae in the bile matched that in the feces at the OTU level. Our data suggests that fecal microbiota dysbiosis may contribute to BTC onset.

Kilotesla plasmoid formation by a trapped relativistic laser beam

A strong quasistationary magnetic field is generated in hollow targets with curved internal surface under the action of a relativistically intense picosecond laser pulse. Experimental data evidence the formation of quasistationary strongly magnetized plasma structures decaying on a hundred picoseconds timescale, with the magnetic field strength of the kilotesla scale. Numerical simulations unravel the importance of transient processes during the magnetic field generation and suggest the existence of fast and slow regimes of plasmoid evolution depending on the interaction parameters. The proposed setup is suited for perspective highly magnetized plasma application and fundamental studies.

The effectiveness of adjuvant chemotherapy for Stage I pancreatic cancer based on the UICC 8th edition

BACKGROUND

Adjuvant chemotherapy is recommended for patients with pancreatic cancer after curative resection. However, there is limited evidence regarding the efficacy and prognostic factors for adjuvant chemotherapy in patients with stage I pancreatic cancer. This study aimed to identify patients in whom chemotherapy was effective and to detect prognostic factors for stage I pancreatic cancer based on guidelines of the 8^th edition of the Union for International Cancer Control (UICC).

METHODS

Between 2009 and 2017, 108 patients diagnosed with stage I pancreatic cancer were enrolled in this study. They were distributed into invasion (n = 68) and non-invasion (n = 40) groups. The relationship between clinicopathological variables, including various prognostic factors, disease-free survival (DFS), and overall survival (OS), were investigated by univariate and multivariate analyses.

RESULTS

Five-year survival in all patients with stage I pancreatic cancer was 38.9%. Adjuvant chemotherapy failed to improve DFS or OS in patients with stage I cancer (DFS, p = 0.26; OS, p = 0.30). In subgroup analysis, adjuvant chemotherapy significantly improved DFS (multivariate-adjusted hazard ratio (HR), 0.40; 95% confidence interval [CI], 0.21-0.78; p = 0.007) and OS (multivariate-adjusted HR, 0.32; 95% CI, 0.15-0.68; p = 0.003) in the invasion group than in non-invasion group. In contrast, in the non-invasion group, adjuvant chemotherapy failed to improve DFS and OS in univariate analysis (DFS, p = 0.992; OS, p = 0.808).

CONCLUSION

For stage I pancreatic cancer, based on guidelines of the UICC 8^th edition, adjuvant chemotherapy may benefit patients with extrapancreatic invasion.

Predictive capability of material screening by fast neutron activation analysis using laser-driven neutron sources

Bright, short-pulsed neutron beams from laser-driven neutron sources (LANSs) provide a new perspective on material screening via fast neutron activation analysis (FNAA). FNAA is a nondestructive technique for determining material elemental composition based on nuclear excitation by fast neutron bombardment and subsequent spectral analysis of prompt γ-rays emitted by the active nuclei. Our recent experiments and simulations have shown that activation analysis can be used in practice with modest neutron fluences on the order of 10⁵ n/cm², which is available with current laser technology. In addition, time-resolved γ-ray measurements combined with picosecond neutron probes from LANSs are effective in mitigating the issue of spectral interference between elements, enabling highly accurate screening of complex samples containing many elements. This paper describes the predictive capability of LANS-based activation analysis based on experimental demonstrations and spectral calculations with Monte Carlo simulations.

Neural network analysis of quasistationary magnetic fields in microcoils driven by short laser pulses

Optical generation of kilo-tesla scale magnetic fields enables prospective technologies and fundamental studies with unprecedentedly high magnetic field energy density. A question is the optimal configuration of proposed setups, where plenty of physical phenomena accompany the generation and complicate both theoretical studies and experimental realizations. Short laser drivers seem more suitable in many applications, though the process is tangled by an intrinsic transient nature. In this work, an artificial neural network is engaged for unravelling main features of the magnetic field excited with a picosecond laser pulse. The trained neural network acquires an ability to read the magnetic field values from experimental data, extremely facilitating interpretation of the experimental results. The conclusion is that the short sub-picosecond laser pulse may generate a quasi-stationary magnetic field structure living on a hundred picosecond time scale, when the induced current forms a closed circuit.

Development of an experimental platform for the investigation of laser-plasma interaction in conditions relevant to shock ignition regime

The shock ignition (SI) approach to inertial confinement fusion is a promising scheme for achieving energy production by nuclear fusion. SI relies on using a high intensity laser pulse (≈10¹⁶ W/cm², with a duration of several hundred ps) at the end of the fuel compression stage. However, during laser-plasma interaction (LPI), several parametric instabilities, such as stimulated Raman scattering and two plasmon decay, nonlinearly generate hot electrons (HEs). The whole behavior of HE under SI conditions, including their generation, transport, and final absorption, is still unclear and needs further experimental investigation. This paper focuses on the development of an experimental platform for SI-related experiments, which simultaneously makes use of multiple diagnostics to characterize LPI and HE generation, transport, and energy deposition. Such diagnostics include optical spectrometers, streaked optical shadowgraph, an x-ray pinhole camera, a two-dimensional x-ray imager, a Cu Kα line spectrometer, two hot-electron spectrometers, a hard x-ray (bremsstrahlung) detector, and a streaked optical pyrometer. Diagnostics successfully operated simultaneously in single-shot mode, revealing the features of HEs under SI-relevant conditions.

A multi-stage scintillation counter for GeV-scale multi-species ion spectroscopy in laser-driven particle acceleration experiments

Particle counting analysis (PCA) with a multi-stage scintillation detector shows a new perspective on angularly resolved spectral characterization of GeV-scale, multi-species ion beams produced by high-power lasers. The diagnosis provides a mass-dependent ion energy spectrum based on time-of-flight and pulse-height analysis of single particle events detected through repetitive experiments. With a novel arrangement of multiple scintillators with different ions stopping powers, PCA offers potential advantages over commonly used diagnostic instruments (CR-39, radiochromic films, Thomson parabola, etc.) in terms of coverage solid angle, detection efficiency for GeV-ions, and real-time analysis during the experiment. The basic detector unit was tested using 230-MeV proton beam from a synchrotron facility, where we demonstrated its potential ability to discriminate major ion species accelerated in laser-plasma experiments (i.e., protons, deuterons, carbon, and oxygen ions) with excellent energy and mass resolution. The proposed diagnostic concept would be essential for a better understanding of laser-driven particle acceleration, which paves the way toward all-optical compact accelerators for a range of applications.

Super-strong magnetic field-dominated ion beam dynamics in focusing plasma devices

High energy density physics is the field of physics dedicated to the study of matter and plasmas in extreme conditions of temperature, densities and pressures. It encompasses multiple disciplines such as material science, planetary science, laboratory and astrophysical plasma science. For the latter, high energy density states can be accompanied by extreme radiation environments and super-strong magnetic fields. The creation of high energy density states in the laboratory consists in concentrating/depositing large amounts of energy in a reduced mass, typically solid material sample or dense plasma, over a time shorter than the typical timescales of heat conduction and hydrodynamic expansion. Laser-generated, high current–density ion beams constitute an important tool for the creation of high energy density states in the laboratory. Focusing plasma devices, such as cone-targets are necessary in order to focus and direct these intense beams towards the heating sample or dense plasma, while protecting the proton generation foil from the harsh environments typical of an integrated high-power laser experiment. A full understanding of the ion beam dynamics in focusing devices is therefore necessary in order to properly design and interpret the numerous experiments in the field. In this work, we report a detailed investigation of large-scale, kilojoule-class laser-generated ion beam dynamics in focusing devices and we demonstrate that high-brilliance ion beams compress magnetic fields to amplitudes exceeding tens of kilo-Tesla, which in turn play a dominant role in the focusing process, resulting either in a worsening or enhancement of focusing capabilities depending on the target geometry.

Transcatheter arterial embolization followed by surgical laparotomy for hemorrhagic shock due to intestinal bleeding: a case report

Background

Acquired jejunal diverticula are relatively rare conditions. While mostly asymptomatic, they can occasionally cause life-threatening complications requiring surgical treatment. We herein report a case of hemorrhagic shock due to jejunal diverticulum with intestinal amyloidosis that was successfully managed via transcatheter arterial embolization (TAE) and surgery.

Case presentation

An 80-year-old female presenting with hematochezia and hemorrhagic shock was transferred to our institution. Contrast-enhanced computed tomography revealed extravasation in the small bowel around the upper jejunum. Massive transfusion was performed with subsequently planning for TAE to control bleeding followed by surgical laparotomy to evaluate the ischemic intestine. First, the second jejunal artery was selectively embolized with a 1:3 mixture of N-butyl cyanoacrylate (NBCA) and iodize oil, after which laparotomy was performed. Multiple jejunal diverticula were detected near Treitz’ ligament, and an induration of NBCA was palpable in the nearby mesentery. The intraoperative diagnosis was massive bleeding from acquired jejunal diverticula for which jejunectomy including the nearby diverticulum was performed to prevent future bleeding. Her postoperative course was stable. Histological examination of the specimen revealed several false diverticula with intestinal amyloidosis.

Conclusion

Hemorrhagic shock due to jejunal diverticulum with intestinal amyloidosis is extremely rare. Combined treatment of TAE and surgical laparotomy appears to be effective, because the bleeding point can be identified by palpation of the embolic material.

Supraceliac aortic cross-clamping to control bleeding from the celiac axis during pancreatic surgery: a case report

Background

Intraoperative bleeding from the celiac axis (CA) can occur during pancreatic surgery, and appropriate management is essential to avoid critical complications. Here, we have reported a case that was managed with supraceliac aortic cross-clamping (SAC) for arterial bleeding from the CA during pancreatic surgery.

Case presentation

A 70-year-old man was diagnosed with pancreatic cancer located in the pancreatic head and body. Preoperative computed tomography showed a stricture at the root of the CA, which may have been caused by a median arcuate ligament. Pancreaticoduodenectomy with division of the median arcuate ligament was scheduled. Uncontrollable bleeding from the root of the CA was observed during surgery. The bleeding was controlled by performing SAC, and a defect in the CA was confirmed. Arterial wall repair was successfully performed under temporal blood control using SAC. The aortic clamp time was 2 min and 51 s, and the intraoperative blood loss was 480 ml.

Conclusions

Although SAC is primarily a procedure for ruptured abdominal aortic aneurysm, it can be useful for the management of CA injuries during pancreatic surgery.

Supplementary Information

The online version contains supplementary material available at 10.1186/s40792-021-01343-z.

Prognostic value of immune factors in the tumor microenvironment of patients with pancreatic ductal adenocarcinoma

BACKGROUND

Both activated tumor-infiltrating lymphocytes (TILs) and immune-suppressive cells, such as regulatory T cells (Tregs), in the tumor microenvironment (TME) play an important role in the prognosis of patients with pancreatic ductal adenocarcinoma (PDAC).

METHODS

The densities of TILs, programmed death receptor 1 (PD-1) + T cells, and forkhead box P3 (Foxp3) + T cells were analyzed by immunohistochemical staining. The associations of the immunological status of the PDAC microenvironment with overall survival (OS) time and disease-free survival (DFS) time were evaluated.

RESULTS

PDAC patients with a high density of TILs in the TME or PD-1-positive T cells in tertiary lymphoid aggregates (TLAs) demonstrated a significantly better prognosis than those with a low density of TILs or PD-1-negativity, respectively. Moreover, PDAC patients with high levels of Foxp3-expressing T cells showed a worse prognosis than those with low levels of Foxp3-expressing T cells. Importantly, even with a high density of the TILs in TME or PD-1-positive T cells in TLAs, PDAC patients with high levels of Foxp3-expressing T cells showed a worse prognosis than patients with low levels of Foxp3-expressing T cells. A PDAC TME with a high density of TILs/high PD-1 positivity/low Foxp3 expression was an independent predictive marker associated with superior prognosis.

CONCLUSION

Combined assessment of TILs, PD-1+ cells, and Foxp3+ T cells in the TME may predict the prognosis of PDAC patients following surgical resection.

Application of a novel surgical difficulty grading system during laparoscopic cholecystectomy

BACKGROUND

Prevention of bile duct injury and vasculo-biliary injury while performing laparoscopic cholecystectomy (LC) is an unsolved problem. Clarifying the surgical difficulty using intraoperative findings can greatly contribute to the pursuit of best practices for acute cholecystitis. In this study, multiple evaluators assessed surgical difficulty items in unedited videos and then constructed a proposed surgical difficulty grading.

METHODS

We previously assembled a library of typical video clips of the intraoperative findings for all LC surgical difficulty items in acute cholecystitis. Fifty-one experts on LC assessed unedited surgical videos. Inter-rater agreement was assessed by Fleiss's κ and Gwet's agreement coefficient (AC).

RESULTS

Except for one item ("edematous change"), κ or AC exceeded 0.5, so the typical videos were judged to be applicable. The conceivable surgical difficulty gradings were analyzed. According to the assessment of difficulty factors, we created a surgical difficulty grading system (agreement probability = 0.923, κ = 0.712, 90% CI: 0.587-0.837; AC₂  = 0.870, 90% CI: 0.768-0.972).

CONCLUSION

The previously published video clip library and our novel surgical difficulty grading system should serve as a universal objective tool to assess surgical difficulty in LC.

Energetic α-particle sources produced through proton-boron reactions by high-energy high-intensity laser beams

In an experiment performed with a high-intensity and high-energy laser system, α-particle production in proton-boron reaction by using a laser-driven proton beam was measured. α particles were observed from the front and also from the rear side, even after a 2-mm-thick boron target. The data obtained in this experiment have been analyzed using a sequence of numerical simulations. The simulations clarify the mechanisms of α-particle production and transport through the boron targets. α-particle energies observed in the experiment and in the simulation reach 10-20 MeV through energy transfer from 20-30 MeV energy incident protons. Despite the lower cross sections for protons with energy above the sub-MeV resonances in the proton-boron reactions, 10^{8}-10^{9}α particles per steradian have been detected.

Dosimetric calibration of GafChromic HD-V2, MD-V3, and EBT3 films for dose ranges up to 100 kGy

A dosimetric calibration of three types of radiochromic films (GafChromic^TM HD-V2, MD-V3, and EBT3) was carried out for absorbed doses (D) ranging up to 100 kGy using a 130 TBq Co60 γ-ray source. The optical densities (ODs) of the irradiated films were acquired with the transmission-mode flatbed film scanner EPSON GT-X980. The calibration data were cross-checked using the 20-MeV proton beam from the azimuthally varying field cyclotron at the Research Center for Nuclear Physics in Osaka University. These experimental results not only present the measurable dose ranges of the films depending on the readout wavelength, but also show consistency with our hypothesis that the OD response curve [log(OD)-log(D) curve] is determined by the volumetric average of the absorption dose and does not strongly depend on the type of radiation for the excitation.

Fast electron transport dynamics and energy deposition in magnetized, imploded cylindrical plasma

Inertial confinement fusion approaches involve the creation of high-energy-density states through compression. High gain scenarios may be enabled by the beneficial heating from fast electrons produced with an intense laser and by energy containment with a high-strength magnetic field. Here, we report experimental measurements from a configuration integrating a magnetized, imploded cylindrical plasma and intense laser-driven electrons as well as multi-stage simulations that show fast electrons transport pathways at different times during the implosion and quantify their energy deposition contribution. The experiment consisted of a CH foam cylinder, inside an external coaxial magnetic field of 5 T, that was imploded using 36 OMEGA laser beams. Two-dimensional (2D) hydrodynamic modelling predicts the CH density reaches [Formula: see text], the temperature reaches 920 eV and the external B-field is amplified at maximum compression to 580 T. At pre-determined times during the compression, the intense OMEGA EP laser irradiated one end of the cylinder to accelerate relativistic electrons into the dense imploded plasma providing additional heating. The relativistic electron beam generation was simulated using a 2D particle-in-cell (PIC) code. Finally, three-dimensional hybrid-PIC simulations calculated the electron propagation and energy deposition inside the target and revealed the roles the compressed and self-generated B-fields play in transport. During a time window before the maximum compression time, the self-generated B-field on the compression front confines the injected electrons inside the target, increasing the temperature through Joule heating. For a stronger B-field seed of 20 T, the electrons are predicted to be guided into the compressed target and provide additional collisional heating. This article is part of a discussion meeting issue 'Prospects for high gain inertial fusion energy (part 2)'.

Relativistic magnetic reconnection in laser laboratory for testing an emission mechanism of hard-state black hole system

Magnetic reconnection in a relativistic electron magnetization regime was observed in a laboratory plasma produced by a high-intensity, large energy, picoseconds laser pulse. Magnetic reconnection conditions realized with a laser-driven several kilotesla magnetic field is comparable to that in the accretion disk corona of black hole systems, i.e., Cygnus X-1. We observed particle energy distributions of reconnection outflow jets, which possess a power-law component in a high-energy range. The hardness of the observed spectra could explain the hard-state x-ray emission from accreting black hole systems.

The segment IV approach: a useful method for achieving the critical view of safety during laparoscopic cholecystectomy in patients with anomalous bile duct

BACKGROUND

The critical view of safety (CVS) method can be achieved by avoiding vasculo-biliary injury resulting from misidentification during laparoscopic cholecystectomy (LC). Although achieving the CVS has become popular worldwide, there is no established standardized technique to achieve the CVS in patients with an anomalous bile duct (ABD). We recently reported our original approach for securing the CVS using a new landmark, the diagonal line of the segment IV of the liver (D-line). The D-line is an imaginary line that lies on the right border of the hilar plate. The cystic structure can be securely isolated along the D-line without any misidentification, regardless of the existence of an ABD. We named this approach the segment IV approach in LC.

METHODS

In this study, we adopted the segment IV approach in patients with an ABD.

RESULTS

From October 2015 to June 2020, 209 patients underwent LC using the segment IV approach. Among them, three (1.4%) were preoperatively diagnosed with an ABD. The branching point of the cystic duct was the posterior sectional duct, anterior sectional duct, or left hepatic duct in each patient. The CVS was achieved in all cases without any complications.

CONCLUSION

It is a promising technique, especially even for patients with an ABD during LC.

Segment IV approach for difficult laparoscopic cholecystectomy

Although achieving the critical view of safety (CVS) is useful for avoiding vasculobiliary injury during laparoscopic cholecystectomy (LC), the CVS cannot always be achieved in cases of severe cholecystitis because of technical difficulties. Herein, we focused on segment IV of the liver and its diagonal line (D-line) as a feasible landmark for carrying out difficult LC. The D-line connects the right dorsal and left ventral corners of segment IV and is used as the vectoral landmark, which is where the gallbladder is first dissected to achieve CVS without misidentification. Conversion to subtotal cholecystectomy along the D-line is also feasible when gallbladder wall scarring is severe. We named this procedure the segment IV approach for LC. Sixty-two consecutive difficult LC (including 27 scheduled LC after percutaneous transhepatic gallbladder drainage [PTGBD] and 35 conservatively treated cases of Tokyo Guidelines [TG] grade II cholecystitis) were managed by the segment IV approach. Successful gallbladder extraction along the D-line was achieved in 44 (71%) cases; all of these cases also achieved CVS following total cholecystectomy. The other 18 (29%) cases were converted to subtotal cholecystectomy because gallbladder extraction along the D-line failed as a result of severe cholecystitis with inflammatory adhesion with surrounding structures. Median operative time and intraoperative blood loss were 135 (range, 54-290) min and 10 (range, 0-100) mL, respectively. No intra- or postoperative complications were observed. The segment IV approach is feasible for achieving CVS and for considering subtotal cholecystectomy in difficult LC cases where scarring of the gallbladder wall is present.

Direct observation of imploded core heating via fast electrons with super-penetration scheme

Fast ignition (FI) is a promising approach for high-energy-gain inertial confinement fusion in the laboratory. To achieve ignition, the energy of a short-pulse laser is required to be delivered efficiently to the pre-compressed fuel core via a high-energy electron beam. Therefore, understanding the transport and energy deposition of this electron beam inside the pre-compressed core is the key for FI. Here we report on the direct observation of the electron beam transport and deposition in a compressed core through the stimulated Cu Kα emission in the super-penetration scheme. Simulations reproducing the experimental measurements indicate that, at the time of peak compression, about 1% of the short-pulse energy is coupled to a relatively low-density core with a radius of 70 μm. Analysis with the support of 2D particle-in-cell simulations uncovers the key factors improving this coupling efficiency. Our findings are of critical importance for optimizing FI experiments in a super-penetration scheme.

Clinical Significance of Tumor-Infiltrating T Cells and Programed Death Ligand-1 in Patients with Pancreatic Cancer

The associations of the immunological status of the pancreatic ductal adenocarcinoma (PDA) microenvironment with prognosis were assessed. A high tumor-infiltrating lymphocyte (TIL) density was associated with a better prognosis. Importantly, even with a high density of TILs, the PDA cells with programed cell death-ligand 1 (PD-L1) expression showed a worse prognosis than the patients with negative PD-L1 expression. A significant association between a better prognosis and a tumor microenvironment with a high TIL density/negative PD-L1 expression was observed. Assessments of a combined immunological status in the tumor microenvironment may predict the prognosis of PDA patients following surgical resection.

Impact of Bile Exposure Time on Organ/space Surgical Site Infections After Pancreaticoduodenectomy

BACKGROUND/AIM

Organ/space surgical site infections (SSIs) are critical complications of pancreaticoduodenectomy. We investigated the impact of the time between division of the common hepatic duct and completion of biliary reconstruction [bile exposure (BE) time] on the occurrence of post-pancreaticoduodenectomy organ/space SSI.

PATIENTS AND METHODS

Sixty-one patients who underwent pancreaticoduodenectomy were retrospectively studied. The impact of perioperative variables and BE time on organ/space SSI occurrence was analyzed.

RESULTS

Organ/space SSIs occurred in 17 patients (28%). Patients were divided into two groups according to BE time. The incidence of organ/space SSIs was significantly higher in the long BE time group than in the short BE time group (42% versus 13%, p=0.0127). Multivariate analysis revealed that long BE times [odds ratio (OR)=4.8; p=0.0240] and soft pancreatic texture (OR=16.5; p=0.0106) were independent risk factors for organ/space SSIs.

CONCLUSION

Long BE time is a risk factor for post-pancreaticoduodenectomy organ/space SSIs. Shortening BE time may reduce organ/space SSI occurrence.

Enhancing laser beam performance by interfering intense laser beamlets

Increasing the laser energy absorption into energetic particle beams represents a longstanding quest in intense laser-plasma physics. During the interaction with matter, part of the laser energy is converted into relativistic electron beams, which are the origin of secondary sources of energetic ions, γ-rays and neutrons. Here we experimentally demonstrate that using multiple coherent laser beamlets spatially and temporally overlapped, thus producing an interference pattern in the laser focus, significantly improves the laser energy conversion efficiency into hot electrons, compared to one beam with the same energy and nominal intensity as the four beamlets combined. Two-dimensional particle-in-cell simulations support the experimental results, suggesting that beamlet interference pattern induces a periodical shaping of the critical density, ultimately playing a key-role in enhancing the laser-to-electron energy conversion efficiency. This method is rather insensitive to laser pulse contrast and duration, making this approach robust and suitable to many existing facilities.

Enhanced coupling of laser energy to the target particles is a fundamental issue in laser-plasma interactions. Here the authors demonstrate increased photon absorption leading into higher laser to electron and proton energy transfer through the interference of multiple coherent beamlets.

Effective method of gallbladder retraction for single-incision laparoscopic cholecystectomy

INTRODUCTION

Recently, single-incision laparoscopic cholecystectomy has been accepted as an alternative to conventional laparoscopic cholecystectomy. The aim of this study was to retrospectively evaluate the safety and feasibility of unique gallbladder retraction methods using an ENDOLOOP® (Ethicon, Tokyo, Japan) and Lapaherclosure™ (Hakko Medical, Tokyo, Japan).

MATERIALS AND SURGICAL TECHNIQUE

From May 2013 to April 2015, 77 patients underwent single-incision laparoscopic cholecystectomy with this retraction technique. During the same period, conventional laparoscopic cholecystectomy was performed in 85 patients; these patients were the control group. The patients' data, including the operative time, total blood loss, conversion rate to laparotomy, and perioperative complications, were compared. Alexis® Wound Retractor XS (Applied Medical, Tokyo, Japan) was inserted through a 25-30-mm vertical transumbilical incision to prevent bile contamination. Next, a SILS Port (Covidien, Tokyo, Japan) was inserted. A flexible 5-mm laparoscope was inserted through the port with a grasper (SILS Clinch, Covidien) and a normal 5-mm scalpel. The fundus of the gallbladder was tied by the ENDOLOOP. The Lapaherclosure was then directly inserted through a right lower intercostal space to capture and pull the Lapaherclosure out. After the cystic artery and duct were cut, the resected gallbladder was directly extracted from the umbilical incision.

DISCUSSION

Several methods and devices have been developed to perform single-incision laparoscopic cholecystectomy, including the suturing method, the Mini Loop Retractor II (Covidien), and the EndoGrab (Virtual Ports, Caesarea, Israel). However, considering medical costs and safety, our retraction method seems to be feasible and comparable to existing methods.

Laparoscopic treatment of a solitary fibrous tumor originating in the cystic plate

Background

Solitary fibrous tumor (SFT) is a rare mesenchymal tumor originating from the tissue underlying the mesothelial layer of the pleura or mediastinum. Other reported sites include the upper respiratory tract, orbit, thyroid, peritoneum, and central nervous system.

Case presentation

We describe a case of a 7 cm SFT that originated in the cystic plate. A liver tumor was an incidental finding in a 49-year-old woman during a regular radiological checkup for uterine fibroids. Imaging revealed a well-circumscribed solid mass between the gallbladder and liver. Intraoperative laparoscopy identified a soft tumor that had progressively expanded behind the gallbladder which was easily separated from the Laennec’s capsule of the liver. Hematoxylin and Eosin and immunohistochemical staining of the tumor tissue found both tangled and patterned arrangements of spindle cells consistent with a SFT derived from the subserosal layer of the gallbladder.

Conclusions

To the best of our knowledge, this is the first report of a SFT originating in the cystic plate.

A multichannel gated neutron detector with reduced afterpulse for low-yield neutron measurements in intense hard X-ray backgrounds

A design of multichannel gated photomultiplier tube (PMT) is presented for the 960-channel neutron time-of-flight detector at the Institute of Laser Engineering of Osaka University. This is important for the fusion science and the nuclear photonics where intense hard X-rays are generated from the interaction of ultra-short laser pulse of petawatt power density with matter. The hard X-rays often overload PMTs and cause signal-induced background noises called afterpulses, making the detection of subsequent neutrons impossible. For this reason, the PMTs are coupled with an electrical time-gating (ETG) system to avoid overloading. The ETG system disables the PMT by modulating the dynode potential during the primary X-ray flash. An after-pulsing suppression technique is demonstrated by applying a reverse bias voltage between the photocathode and the first dynode. The presented multichannel scheme provides a gate response time of 80 ns, a signal cutoff ratio of 2.5 × 10², and requires reasonably low power consumption.

A large-aperture high-sensitivity avalanche image intensifier panel

A large-aperture high-sensitivity image intensifier panel that consists of an avalanche photodiode array and a light-emitting diode array is presented. The device has 40% quantum efficiency, over 10⁴ optical gain, and 80-ns time resolution. The aperture size of the device is 20 cm, and with the current manufacturing process, it can be scaled to arbitrarily larger sizes. The device can intensify the light from a single particle scintillation emission to an eye-visible bright flash. The image resolution of the device is currently limited by the size of the avalanche photodiode that is 2 mm, although it can be scaled to smaller sizes in the near future. The image intensifier is operated at a small voltage, typically +57 V. The device can be applied to various applications, such as scintillation imaging, night vision cameras, and an image converter from non-visible light (such as infrared or ultraviolet) to visible light.

Sentinel Node Navigation Surgery for Early Gastric Cancer: Analysis of Factors Which Affect Direction of Lymphatic Drainage

BACKGROUND AND PURPOSE

We started performing sentinel node navigation surgery (SNNS) for patients with early gastric cancer (EGC) using infrared ray electronic endoscopy (IREE) with indocyanine green injection from year 2000. The EGCs usually have complex lymphatic drainage, unidirectional or multidirectional lymphatic flow. In this study, we investigated and clarified factors that affect the direction of gastric lymphatic drainage.

PATIENTS AND METHOD

Consecutive 60 patients with EGC who underwent SNNS by IREE from year 2006 to 2014 were enrolled to this study. Patients' age, gender, location of tumors, operative method, previous treatment by endoscopic submucosal dissection (ESD), presence of pathological ulcerative scar and maximum tumor diameter were enrolled as parameters which may affect direction of lymphatic drainage and analyzed.

RESULT

Bivariate analysis demonstrated that the presence of pathological ulcerative scar (P = 0.01), tumor location (g.c vs. a.w vs. p.w vs. l.c, P = 0.01), and maxim tumor diameter (P = 0.0003) were relevant to direction of gastric lymphatic drainage. Multivariate analysis showed that tumor location (g.c/a.w/p.w vs. l.c, odds ratio 8.227, P = 0.011) and the maximum tumor diameter (odds ratio 1.057, P = 0.037) are independent factors that affect direction of gastric lymphatic flow. Of tumors, 78% located at lesser curvature had unidirectional lymphatic drainage, and 93% of tumors whose diameter was 40 mm and more had multidirectional lymphatic drainage.

CONCLUSION

Our investigation revealed that the tumor location and tumor diameter were the key factors which affect the direction of lymphatic drainage, which is useful fact to understand the complexity of gastric lymphatic drainage.

Prognostic significance of Wilms' tumor 1 expression in patients with pancreatic ductal adenocarcinoma

The only current curative treatment for patients with pancreatic ductal adenocarcinoma (PDA) is surgical resection, and certain patients still succumb to disease shortly after complete surgical resection. Wilms' tumor 1 (WT1) serves an oncogenic role in various types of tumors; therefore, in the present study, WT1 protein expression in patients with PDA was analyzed and the association with overall survival (OS) and disease-free survival (DFS) time in patients with PDA was assessed following surgical resection. A total of 50 consecutive patients with PDA who received surgical resection between January 2005 and December 2015 at the Jikei University Kashiwa Hospital (Kashiwa, Chiba, Japan) were enrolled. WT1 protein expression in PDA tissue was measured using immunohistochemical staining. Furthermore, laboratory parameters were measured within 2 weeks of surgery, and systemic inflammatory response markers were evaluated. WT1 protein expression was detected in the nucleus and cytoplasm of all PDA cells and in tumor vessels. WT1 exhibited weak staining in the nuclei of all PDA cells; however, the cytoplasmic expression of WT1 levels was classified into four groups: Negative (n=0), weak (n=19), moderate (n=23) and strong (n=8). In patients with PDA, it was demonstrated that the OS and DFS times of patients with weak cytoplasmic WT1 expression were significantly prolonged compared with those of patients with moderate-to-strong cytoplasmic WT1 expression, as determined by log-rank test (P=0.0005 and P=0.0001, respectively). Furthermore, an association between the density of WT1-expressing tumor vessels and worse OS/DFS times was detected. Multivariate analysis also indicated a significant association between the overexpression of WT1 in PDA tissue and worse OS/DFS times. To the best of our knowledge, the present study is the first to demonstrate that moderate-to-strong overexpression of WT1 in the cytoplasm of PDA cells is significantly associated with worse OS/DFS times. Therefore, overexpression of WT1 in the cytoplasm of PDA cells may impact the recurrence and prognosis of patients with PDA following surgical resection. The results further support the development of WT1-targeted therapies to prolong survival in all patients with PDA.

A case of portal vein thrombosis caused by blunt abdominal trauma in a patient with low protein C activity

Portal vein thrombosis (PVT) is caused by several conditions including infection, malignancies, surgery, medications, and coagulation disorders. However, PVT caused by low-energy injury is very rare. A 51-year-old man visited a clinic with a 2-day history of abdominal pain following blunt abdominal trauma. Contrast-enhanced computed tomography (CT) revealed thrombosis in both the portal vein and splenic vein, and he was transferred to our hospital with a diagnosis of PVT. Anticoagulant therapy was initiated using unfractionated heparin. A repeat CT scan revealed enlargement of the thrombus, which occluded the main trunk and first right branch of the portal vein. Laboratory data before heparin administration suggested low protein C activity. Anticoagulation therapy was continued with intermittent assessment of the size of the thrombus and degree of coagulation. On day 23, enhanced CT showed marked shrinkage of the thrombus compared with that on day 8. On day 30, the patient was discharged with a therapeutic prothrombin time-international normalized ratio. Here we present a case of PVT caused by low-energy trauma of the upper abdomen in a patient with a background of low protein C activity that was successfully treated without invasive surgery.

Tying modified clinch knots during single-incision laparoscopic surgery

INTRODUCTION

Recent advances in single-incision laparoscopic surgery (SILS) have caused increased difficulties when tying knots because of the limited working space. Although extracorporeal knot-tying techniques may be a practical alternative choice in SILS, it is not always appropriate. For example, sliding resistance may be encountered when tying knots for a Z-shaped suture, and it could damage the sutured tissue.

MATERIALS AND SURGICAL TECHNIQUE

The clinch knot is a kind of slipknot that has been historically used by fishermen. We modified it for SILS so that it has a locking mechanism caused by knot deformation. We apply pre-tied modified clinch (MC) knots in the peritoneal cavity with a needle driver. After the suture, the needle is pulled through the knot and exits out the trocar. After the MC knot has been tightened, locking is achieved by pulling the other end of the axial thread and folding the thread in an acute angle. Because both ends of the suture thread leave the trocar together, every step can be carried out quickly through a single trocar. The MC knot can also be used to tie knots for Z-shaped sutures because of its short sliding distance. Twelve simple interrupted sutures and 55 Z-shaped sutures were tied by MC knot in SILS. All knots were successfully tied, and the mean required time to tie a knot was 27 s.

DISCUSSION

The MC knot is feasible knot-tying procedure especially for a Z-shaped suture during SILS.

Tokyo Guidelines 2018: surgical management of acute cholecystitis: safe steps in laparoscopic cholecystectomy for acute cholecystitis (with videos)

In some cases, laparoscopic cholecystectomy (LC) may be difficult to perform in patients with acute cholecystitis (AC) with severe inflammation and fibrosis. The Tokyo Guidelines 2018 (TG18) expand the indications for LC under difficult conditions for each level of severity of AC. As a result of expanding the indications for LC to treat AC, it is absolutely necessary to avoid any increase in bile duct injury (BDI), particularly vasculo-biliary injury (VBI), which is known to occur at a certain rate in LC. Since the Tokyo Guidelines 2013 (TG13), an attempt has been made to assess intraoperative findings as objective indicators of surgical difficulty; based on expert consensus on these difficulty indicators, bail-out procedures (including conversion to open cholecystectomy) have been indicated for cases in which LC for AC is difficult to perform. A bail-out procedure should be chosen if, when the Calot's triangle is appropriately retracted and used as a landmark, a critical view of safety (CVS) cannot be achieved because of the presence of nondissectable scarring or severe fibrosis. We propose standardized safe steps for LC to treat AC. To achieve a CVS, it is vital to dissect at a location above (on the ventral side of) the imaginary line connecting the base of the left medial section (Segment 4) and the roof of Rouvière's sulcus and to fulfill the three criteria of CVS before dividing any structures. Achieving a CVS prevents the misidentification of the cystic duct and the common bile duct, which are most commonly confused. Free full articles and mobile app of TG18 are available at: http://www.jshbps.jp/modules/en/index.php?content_id=47. Related clinical questions and references are also included.

Guiding of relativistic electron beams in dense matter by laser-driven magnetostatic fields

Intense lasers interacting with dense targets accelerate relativistic electron beams, which transport part of the laser energy into the target depth. However, the overall laser-to-target energy coupling efficiency is impaired by the large divergence of the electron beam, intrinsic to the laser-plasma interaction. Here we demonstrate that an efficient guiding of MeV electrons with about 30 MA current in solid matter is obtained by imposing a laser-driven longitudinal magnetostatic field of 600 T. In the magnetized conditions the transported energy density and the peak background electron temperature at the 60-μm-thick target's rear surface rise by about a factor of five, as unfolded from benchmarked simulations. Such an improvement of energy-density flux through dense matter paves the ground for advances in laser-driven intense sources of energetic particles and radiation, driving matter to extreme temperatures, reaching states relevant for planetary or stellar science as yet inaccessible at the laboratory scale and achieving high-gain laser-driven thermonuclear fusion.

Collimated Propagation of Fast Electron Beams Accelerated by High-Contrast Laser Pulses in Highly Resistive Shocked Carbon

Collimated transport of ultrahigh intensity electron current was observed in cold and in laser-shocked vitreous carbon, in agreement with simulation predictions. The fast electron beams were created by coupling high-intensity and high-contrast laser pulses onto copper-coated cones drilled into the carbon samples. The guiding mechanism-observed only for times before the shock breakout at the inner cone tip-is due to self-generated resistive magnetic fields of ∼0.5-1  kT arising from the intense currents of fast electrons in vitreous carbon, by virtue of its specific high resistivity over the range of explored background temperatures. The spatial distribution of the electron beams, injected through the samples at different stages of compression, was characterized by side-on imaging of hard x-ray fluorescence.

Prognostic impact of carbohydrate sulfotransferase 15 in patients with pancreatic ductal adenocarcinoma

Patients with pancreatic ductal adenocarcinoma (PDA) typically succumb to mortality early, even following surgical resection. Therefore, prognostic factors associated with early mortality are required to improve the survival of patients with PDA following surgical resection. Carbohydrate sulfotransferase 15 (CHST15) is responsible for the biosynthesis of sulfated chondroitin sulfate E (CS-E), which serves a pivotal function in cancer progression by cleaving CD44. CHST15 and CD44 expression in PDA tissue were assessed as a prognostic factor in patients with PDA following surgical resection. A total of 36 consecutive patients with PDA were enrolled following surgical resection between January 2008 and December 2014. The intensities of CHST15 and CD44 expression were analyzed by immunohistochemical staining. The recurrence period was significantly earlier in the strong CHST15 expression group compared with the negative-to-moderate CHST15 expression group. Overall survival (OS) was also significantly decreased in the strong CHST15 expression group compared with the negative-to-moderate CHST15 expression group. Multivariate analysis also indicated significant associations between CHST15 overexpression and disease-free survival (DFS) and OS. However, expression of CD44 in PDA tissue was not associated with DFS or OS. The present study has demonstrated for the first time that high CHST15 expression in PDA tissue may represent a potential predictive marker of DFS and OS in patients with PDA following surgical resection.

Ultrafast probing of magnetic field growth inside a laser-driven solenoid

We report on the detection of the time-dependent B-field amplitude and topology in a laser-driven solenoid. The B-field inferred from both proton deflectometry and Faraday rotation ramps up linearly in time reaching 210 ± 35 T at the end of a 0.75-ns laser drive with 1 TW at 351 nm. A lumped-element circuit model agrees well with the linear rise and suggests that the blow-off plasma screens the field between the plates leading to an increased plate capacitance that converts the laser-generated hot-electron current into a voltage source that drives current through the solenoid. ALE3D modeling shows that target disassembly and current diffusion may limit the B-field increase for longer laser drive. Scaling of these experimental results to a National Ignition Facility (NIF) hohlraum target size (∼0.2cm^{3}) indicates that it is possible to achieve several tens of Tesla.