SVDF: enhancing structural variation detect from long-read sequencing via automatic filtering strategies.

Structural variation (SV) is an important form of genomic variation that influences gene function and expression by altering the structure of the genome. Although long-read data have been proven to better characterize SVs, SVs detected from noisy long-read data still include a considerable portion of false-positive calls. To accurately detect SVs in long-read data, we present SVDF, a method that employs a learning-based noise filtering strategy and an SV signature-adaptive clustering algorithm, for effectively reducing the likelihood of false-positive events. Benchmarking results from multiple orthogonal experiments demonstrate that, across different sequencing platforms and depths, SVDF achieves higher calling accuracy for each sample compared to several existing general SV calling tools. We believe that, with its meticulous and sensitive SV detection capability, SVDF can bring new opportunities and advancements to cutting-edge genomic research.

Complex genome assembly based on long-read sequencing.

High-quality genome chromosome-scale sequences provide an important basis for genomics downstream analysis, especially the construction of haplotype-resolved and complete genomes, which plays a key role in genome annotation, mutation detection, evolutionary analysis, gene function research, comparative genomics and other aspects. However, genome-wide short-read sequencing is difficult to produce a complete genome in the face of a complex genome with high duplication and multiple heterozygosity. The emergence of long-read sequencing technology has greatly improved the integrity of complex genome assembly. We review a variety of computational methods for complex genome assembly and describe in detail the theories, innovations and shortcomings of collapsed, semi-collapsed and uncollapsed assemblers based on long reads. Among the three methods, uncollapsed assembly is the most correct and complete way to represent genomes. In addition, genome assembly is closely related to haplotype reconstruction, that is uncollapsed assembly realizes haplotype reconstruction, and haplotype reconstruction promotes uncollapsed assembly. We hope that gapless, telomere-to-telomere and accurate assembly of complex genomes can be truly routinely achieved using only a simple process or a single tool in the future.

Identification of adaptor proteins by incorporating deep learning and PSSM profiles.

Adaptor proteins, also known as signal transduction adaptor proteins, are important proteins in signal transduction pathways, and play a role in connecting signal proteins for signal transduction between cells. Studies have shown that adaptor proteins are closely related to some diseases, such as tumors and diabetes. Therefore, it is very meaningful to construct a relevant model to accurately identify adaptor proteins. In recent years, many studies have used a position-specific scoring matrix (PSSM) and neural network methods to identify adaptor proteins. However, ordinary neural network models cannot correlate the contextual information in PSSM profiles well, so these studies usually process 20×N (N > 20) PSSM into 20×20 dimensions, which results in the loss of a large amount of protein information; This research proposes an efficient method that combines one-dimensional convolution (1-D CNN) and a bidirectional long short-term memory network (biLSTM) to identify adaptor proteins. The complete PSSM profiles are the input of the model, and the complete information of the protein is retained during the training process. We perform cross-validation during model training and test the performance of the model on an independent test set; in the data set with 1224 adaptor proteins and 11,078 non-adaptor proteins, five indicators including specificity, sensitivity, accuracy, area under the receiver operating characteristic curve (AUC) metric and Matthews correlation coefficient (MCC), were employed to evaluate model performance. On the independent test set, the specificity, sensitivity, accuracy and MCC were 0.817, 0.865, 0.823 and 0.465, respectively. Those results show that our method is better than the state-of-the art methods. This study is committed to improve the accuracy of adaptor protein identification, and laid a foundation for further research on diseases related to adaptor protein. This research provided a new idea for the application of deep learning related models in bioinformatics and computational biology.

A Fast Self-Calibration Method for Dual-Axis Rotational Inertial Navigation Systems Based on Invariant Errors.

In order to ensure that dual-axis rotational inertial navigation systems (RINSs) maintain a high level of accuracy over the long term, there is a demand for periodic calibration during their service life. Traditional calibration methods for inertial measurement units (IMUs) involve removing the IMU from the equipment, which is a laborious and time-consuming process. Reinstalling the IMU after calibration may introduce new installation errors. This paper focuses on dual-axis rotational inertial navigation systems and presents a system-level self-calibration method based on invariant errors, enabling high-precision automated calibration without the need for equipment disassembly. First, navigation parameter errors in the inertial frame are expressed as invariant errors. This allows the corresponding error models to estimate initial attitude even more rapidly and accurately in cases of extreme misalignment, eliminating the need for coarse alignment. Next, by utilizing the output of a gimbal mechanism, angular velocity constraint equations are established, and the backtracking navigation is introduced to reuse sensor data, thereby reducing the calibration time. Finally, a rotation scheme for the IMU is designed to ensure that all errors are observable. The observability of the system is analyzed based on a piecewise constant system method and singular value decomposition (SVD) observability analysis. The simulation and experimental results demonstrate that this method can effectively estimate IMU errors and installation errors related to the rotation axis within 12 min, and the estimated error is less than 4%. After using this method to compensate for the calibration error, the velocity and position accuracies of a RINS are significantly improved.

dPromoter-XGBoost: Detecting promoters and strength by combining multiple descriptors and feature selection using XGBoost.

Promoters play an irreplaceable role in biological processes and genetics, which are responsible for stimulating the transcription and expression of specific genes. Promoter abnormalities have been found in some diseases, and the level of promoter-binding transcription factors can be used as a marker before a disease occurs. Hence, detecting promoters from DNA sequences has important biological significance, particular, distinguishing strong promoters can help to elucidate differences in gene expression and the mechanisms of specific diseases. With the introduction of third-generation sequencing, it is difficult to match the speed of sequencing to the speed of labeling promoters experimentally. Many computing models have been designed to fill this gap and identify unlabeled DNA. However, their feature representation methods are very singular, which cannot reflect the information contained in the original samples. With the aim of avoiding information loss, we propose a computational model based on multiple descriptors and feature selection to jointly express samples. It is worth mentioning that a new feature descriptor called K-mer word vector is defined. The promoter model of multiple feature descriptors dominated by K-mer word vector achieves similar performance to existing methods, the sensitivity of 85.72% can distinguish the promoter more effectively than other methods. Furthermore, the performance of the promoter strength has surpassed published methods, and accuracy of 77.00% greatly improves the ability to distinguish between strong and weak promoters.

Short-Term Outcomes of In Situ Fenestration in Total Endovascular Aortic Arch Treatment.

OBJECTIVES: The aim of this study was to analyze the short-term outcomes of in situ fenestration and discuss its feasibility and safety for the treatment of aortic dissection or aneurysm involving aortic arch. METHODS: A retrospective single-center review was conducted on patients who were treated with ISF technique to revascularize supra-arch branches from Jun 2017 to Oct 2019. Computed tomographic angiography was performed to assess the patency of bridging stents, endoleaks and prognosis prior to discharge, after 3 months, 6 months, 12 months and yearly thereafter. Patient demographics, operative details, clinical outcomes, and complications were analyzed and then discussed in this paper. RESULTS: A total of 21 patients were diagnosed with arch pathologies, 5 type A aortic dissections, 12 type B aortic dissections and 4 thoracic aortic aneurysms. There were 19 men and 2 women (mean age 60.7 ± 15.3). 8 cases were treated with three-fenestration stent grafts, 1 case with two-fenestration stent graft, and 12 cases with single-fenestration stent grafts. Overall technical success rate was 95.2%. Mean operation time was 227.4 ± 143.8 minutes. Complications were intraoperative hemorrhage (>1000 ml, 2), stroke (2), hydropericardium (1) and endoleaks (2 type Ⅲ, 1 type Ⅰ). There was no aorta-related mortality or late endoleaks during the mean follow-up of 25.5 ± 6.2 months. All the bridging stents remained patent and there was no migration according to follow-up Computed tomographic angiography. CONCLUSIONS: With low complication and mortality rate, ISF is an effective and feasible method for the total endovascular aortic arch repair. Long-term follow-up study is needed to evaluate its durability.

Surgical revision for pancreatojejunostomy stricture: a case series of 14 patients.

BACKGROUND: Pancreatojejunostomy stricture (PJS) is a rare long-term complication of pancreaticojejunal anastomosis. This study aimed to investigate the role of surgery in the management of pancreatojejunostomy strictures. METHODS: The database of the Pancreas Center of Nanjing Medical University was retrospectively screened for patients who underwent a surgical revision for PJS between June 2012 and August 2019, and their clinical characteristics and management modalities were reviewed. RESULTS: Fourteen consecutive cases were retrieved, the median age at index operation was 41.1 years (19-71). The average time between the two operations was 70.6 months (8-270 months). Index procedures included pancreaticoduodenectomy (PD) (7/14, 50%), pylorus-preserving PD (4/14, 28.6%), Berger procedure (2/14, 14.3%), and middle pancreatectomy (1/14, 7.1%). The diameter of the main pancreatic duct was < 4 mm in all 14 cases, and nine underwent pancreaticojejunostomy (PJ) stenting during the index operation. The most frequent complaints were abdominal pain (6/14, 42.9%), recurrent acute pancreatitis (6/14, 42.9%), pancreatic fistula (1/14, 7.1%), and abdominal distention (1/14, 7.1%). The diagnosis of PJ stricture was confirmed by computed tomography or magnetic resonance imaging in all cases. All patients had a main duct diameter > 5 mm before surgical revision. All patients underwent wedge excision with interrupted one-layer suturing with absorbable sutures and without stent placement. In this series, only one patient required reoperation. Upon follow-up, 11 of 12 patients had complete resolution of the PJ stricture. CONCLUSION: PJS is a long-term complication of pancreatojejunostomy. Surgical revision of the anastomosis is a safe and effective treatment modality.

Circular dichroism metamirror with diversified chiral molecules combinations.

In this paper, we propose a giant circular dichroism (CD) chiral metamirror that differentially absorbs circularly polarized (CP) waves with dual/multi bands. The structure is composed of two variable τ resonators with counter split opening directions and different eigenfrequencies. Even more important, these two resonators are aligned vertically, and then integrated into one periodical unit cell, which results in the high-efficiency absorptive CD. The chiral metamirror has a narrow-band absorption of the left-handed circularly polarized (LCP) wave for lower resonance, and a broadband absorption of the right-handed circularly polarized (RCP) wave in the higher-frequency range. Optical resonator designs with diversified chiral molecules combinations are further studied in detail. Through the study of different periodic arrangements, parameters scanning optimization, and power loss distributions, it is proved that the overall permutation symmetry breakdown of total combined chiral molecules is the determining factor for the absorptive CD. Based on the principle in the microwave model, two mid-infrared chiral metamirrors are further realized, which can still show good spin-dependent absorption. This multi-polarization and multifunction response advance novel photonic devices for a variety of applications including CP laser, biomolecules detection, and energy harvester.

Development and validation of a ferroptosis-related prognostic model in pancreatic cancer.

BACKGROUND: The purpose of this study was to identify ferroptosis-related genes (FRGs) associated with the prognosis of pancreatic cancer and to construct a prognostic model based on FRGs. METHODS: Based on pancreatic cancer data obtained from The Cancer Genome Atlas database, we established a prognostic model from 232 FRGs. A nomogram was constructed by combining the prognostic model and clinicopathological features. Gene Expression Omnibus datasets and tissue samples obtained from our center were utilized to validate the model. The relationship between risk score and immune cell infiltration was explored by CIBERSORT and TIMER. RESULTS: The prognostic model was established based on four FRGs (ENPP2, ATG4D, SLC2A1 and MAP3K5), and the risk score was demonstrated to be an independent risk factor in pancreatic cancer (HR 1.648, 95% CI 1.335-2.035, p < 0.001). Based on the median risk score, patients were divided into a high-risk group and a low-risk group. The low-risk group had a better prognosis than the high-risk group. In the high-risk group, patients treated with chemotherapy had a better prognosis. The nomogram showed that the model was the most important element. Gene set enrichment analysis identified three key pathways, namely, TGFß signaling, HIF signaling pathway and the adherens junction. The prognostic model may be associated with infiltration of immune cells such as M0 macrophages, M1 macrophages, CD4 + T cells and CD8 + T cells. CONCLUSION: The ferroptosis-related prognostic model can be employed to predict the prognosis of pancreatic cancer. Ferroptosis is an important marker, and immunotherapy may be a potential therapeutic target for pancreatic cancer.

Sub-adventitial divestment technique for resecting artery-involved pancreatic cancer: a retrospective cohort study.

PURPOSE: To introduce sub-adventitial divestment technique (SDT), a procedure to remove the tumor while preserving the artery during curative pancreatectomy. Peri-operative safety profile was also evaluated. METHODS: In a single center consecutive series of pancreatectomy for pancreatic cancer, the outcome of patients who had pancreatectomy with SDT was compared to standard pancreatic surgery. RESULTS: From June 2014 to June 2016, 72 patients had pancreatectomy with SDT and 235 had standard surgery. Tumor stage was T4 in all 72 (100%) tumors removed using SDT compared to four (2%) with standard pancreatectomy (p < 0.001). All 72 (100%) tumors in the SDT group were stage III compared to 24 (10%) in the standard surgery group (p < 0.001). Both groups had a high proportion of poorly differentiated tumors (52 (72%) and 163 (69%) respectively) and perineural tumor invasion (62 (86%) and 186 (79%) respectively). R1 (< 1 mm) was found in 24 (86%) of 28 tumors in the SDT group, and in 72 (60%) out of 120 standard pancreatectomy tumors (p = 0.01). Complications occurred in 29 (40%) of the SDT group and in 88 (37%) of the standard group. The in-hospital mortality was four (6%) in the SDT group and one (0.4%) in the standard group (p = 0.01), with a 90-day mortality of 5 (8%)/60 and 6 (3%)/209 (p = 0.07) respectively. CONCLUSIONS: The sub-adventitial divestment technique appeared to be an effective surgical technique to remove the tumor while preserving the artery. This approach warrants further validation in prospective studies.

Coronary Stents Decorated by Heparin/NONOate Nanoparticles for Anticoagulant and Endothelialized Effects.

In the treatment of coronary artery disease (CAD), the use of stent implantation often leads to clinical complications such as restenosis, delayed endothelial healing, and thrombosis. Here, we develop a double drug sustained-release coating for the stent surface by grafting heparin/NONOate nanoparticles (Hep/NONOates). The Hep/NONOates and surface modification of the stent were characterized by X-ray photoelectron spectroscopy, attenuated total reflection Fourier-transform infrared spectroscopy, static water contact angle, and scanning electron microscopy (SEM), and the release behaviors of the anticoagulant, heparin (Hep) and the bioactive molecule, nitric oxide (NO) were studied. Furthermore, the blood compatibility and cytotoxicity of the modified stent were evaluated by whole blood adhesion and platelet adhesion tests, hemolysis assay, morphological changes of red blood cells, plasma recalcification time assay, in vitro coagulation time tests, and MTT assay. Finally, the results of a rabbit carotid artery stent implantation experiment showed that the double drug sustained-release coating for the stent can accelerate regeneration of endothelial cells and keep good anticoagulant activity. This study can provide new design ideas based on nanotechnology for improving the safety and effectiveness of drug-eluting stents.

Prognostic Nomogram for Resected Pancreatic Adenocarcinoma: A TRIPOD-Compliant Retrospective Long-Term Survival Analysis.

BACKGROUND: Prognostic prediction had been widely used in various cancer entities, from early screening to end-stage patient caring. Currently, there is hardly any well-validated nomogram which exists for long-term survival prediction in pancreatic adenocarcinoma (PC) patients in a post-surgery setting. Our objectives are to identify possible prognostic factors in PC patients following radical resection and to develop a prognostic nomogram based on independent survival predictors. METHODS: From 2009 to 2014, a total of 432 PC patients who underwent curative intended surgeries with complete follow-up data were included in this current retrospective long-term survival analysis. Clinicopathological data were extracted from medical records, and all missing values (percentage 0.9-8.3%) were imputed five times with the "PMM" method. Cox proportional hazards models were utilized. A nomogram was formulated based on results from the multivariate regression model so as to predict OS at 1-, 2- and 3-year as well as median OS. Validations, including discrimination and calibration, were carried out with 1000 bootstrap resamples. External validation was conducted in order to verify the accuracy of our nomogram at 1 and 2 years by utilizing the clinicopathological data of 122 PC patients who underwent curative intended surgeries in 2015 in our centre. RESULTS: Age, abdominal pain, back pain, tumour location, preoperative neutrophil-lymphocyte ratio, preoperative CA19-9, tumour differentiation, microscopic nerve invasion, microscopic vascular invasion, T stage, lymph node ratio, M stage and adjuvant chemotherapy were all assembled into nomogram. The concordance index (C-index) of internal and external validation was 0.702 and 0.688, respectively. The C-index of the TNM staging system was 0.572 (P < 0.001 vs. nomogram). CONCLUSION: Our prognostic nomogram based on clinicopathological parameters shows good performance in long-term survival prediction in PC patients following radical surgery and could play a role in further clinical utilization.

Application of 2,4-bis(halomethyl)quinoline: synthesis and biological activities of 2,4-bis(benzofuran-2-yl)- and 2,4-bis(aroxymethyl)quinolines.

In the present investigation, the synthesis of a new type of halomethylquinoline building block, i.e., ethyl 4-(bromomethyl)-2-(chloromethyl)quinoline-3-carboxylate, and its synthetic applications in the reaction with salicylaldehydes or phenols to make a range of structurally novel and intriguing 2,4-bis(benzofuran-2-yl)quinoline- and 2,4-bis(aroxymethyl)quinoline-3-carboxylic acids is described. Our newly synthesized compounds belong to a new class of quinoline derivatives, and their structures were elucidated on the basis of their spectral data and elemental analyses. Screening for in vitro anti-tubercular against Mycobacterium smegmatis and anti-bacterial activities against Bacillus subtilis, Staphylococcus aureus, Escherichia coli and Pseudomonas aeruginosa was carried out. Compounds 5e and 5g showed significant anti-tubercular activity comparable with the reference rifampicin and might be used as promising candidates for further investigation.

Feasibility of bile duct as venous graft for venous reconstruction in pancreatic surgery: An animal experimental study.

OBJECTIVE: Pancreatic cancer is a kind of high malignant tumor with a poor prognosis. The aim is to determine whether the dilated bile duct can be used to reconstruct the vessels. METHODS: An animal model of jugular vein and portal vein reconstruction was established using the bile duct. A total of 20 landrace pigs were selected to undergo jugular vein reconstruction or portal vein reconstruction using the bile duct as a patch or bridge. The patency was evaluated by color Doppler, the reconstructed segments were removed and examined macroscopically and histologically at specified intervals, and the results were compared with synthetic vessels (IMPRA straight, 10s03-19). RESULTS: The lumen was patent, although a low level thrombosis was observed when jugular or portal vein patching was used. For bridging, stenosis of the lumen was observed, and necrosis appeared when the bile duct was used for bridging, indicating that it is feasible to reconstruct the jugular vein and portal vein with a bile duct patch. However, the bridge was not feasible possibly due to loss of blood supply, and consequent necrosis and fibrosis. CONCLUSION: The bile duct is technically feasible, but the outcomes are unsatisfactory.

Multiplet independent resonance modes in multiplexed gratings.

Resonance modes in usual optical resonators are orthogonal, but correlated and their resonance properties cannot be independently controlled. Multiplexed gratings, consisting of multiple harmonic grating features, show multiplet resonance modes that can be independently adjusted. This offers flexibility in designing resonance characteristics for various potential applications in nonlinear optics and controlling/enhancement of light-matter interactions, e.g., to resonantly enhance the local densities of photonic modes of both the excitation and emission light in photoluminescence, which cannot be intentionally achieved with conventional resonators. Here we report the design, characteristics and experimental implementation of the multiplexed metal gratings that have doublet or triplet resonance modes. Based on numerical simulations, we investigated dependences of the resonance modes, field distributions and local field enhancements on structure features of the gratings. In implementation, we elaborated the experimental considerations, and demonstrated the consistency in structure features and their resonance characteristics for designed and as-fabricated multiplexed grating resonators.

Central pancreatectomy for early-stage pancreatic ductal adenocarcinoma: a single-center case-control study.

PURPOSE: Central pancreatectomy (CP) has been applied for treating benign and low-grade malignant tumors in pancreatic neck, but studies regarding CP for pancreatic ductal adenocarcinoma (PDAC) are quite limited. We aimed to investigate the role of central pancreatectomy in the treatment of PDAC in the neck of the pancreas. METHODS: Patients who underwent CP at our hospital between 2009 and 2016 were identified. Patients treated by distal pancreatectomy (DP) were matched according to the tumor size, location, and staging. The surgical and survival outcomes were compared between the CP and DP groups. RESULTS: Nine patients had CP. Five (56%) had postoperative complications and three (33%) had clinically significant (grade B + C) fistula. No significant difference was found between the CP and DP groups for the rate of overall morbidity, pancreatic fistula, reoperation, and readmission. Tumor size was smaller in the CP group compared to the DP group. The mortality of both groups was zero. The median postoperative survival was similar between the two groups (20.4 months for CP vs 19.4 months for DP, P = 0.842). CONCLUSIONS: CP is safe for patients with small PDAC at the neck of the pancreas. Considering the good preservation of pancreatic endocrine and exocrine functions, CP could be considered as an alternative procedure for single small PDAC in pancreatic neck.

Anomalous resonant reflection in a Fabry-Perot cavity filled with weakly scattering medium.

In this work, we fabricated a metallic Fabry-Perot cavity, filled with a weakly scattering medium of unsintered solgel silica, on a glass substrate. We found anomalous asymmetric resonance reflection spectra of this structure, besides the effects of scattering loss in cavity. The asymmetric reflection is shown to be dependent on the media on both sides of the cavity. It is thought that, as the weakly scattering medium locates between highly reflecting boundaries and the cavity length is far less than the mean free path of light in the medium, light scattering in the medium is enhanced at the resonance conditions and the scattering centers act as elementary sources emitting the scattered incoherent light to the outside of the cavity from both its ends. The asymmetric reflection then results from lossy total internal reflection of the scattered light at one of the boundaries, eventually leaking to the outside of the cavity with the higher index and contributing to the measured backside reflectance.

Diagnosis and treatment of solid-pseudopapillary tumors of the pancreas: A single institution experience with 97 cases.

BACKGROUND/OBJECTIVES: We evaluated the diagnoses and surgical management of solid pseudopapillary tumors of the pancreas (SPTP) in a single center setting. METHODS: Demographic details, clinical presentations, imaging features, surgical strategies, and pathological findings of 97 consecutive patients who underwent surgery for pathologically confirmed SPTP between 2008 and 2016 were analyzed retrospectively. RESULTS: A total of 97 patients with SPTP accounted for 2.15% of total pancreatic surgeries (N = 4508). The mean age at diagnosis was 31.6 ±â€¯13.92 years (range: 7-83 years), and males:females were 85:12. Chief complaints were abdominal pain or discomfort (n = 50). The mean transverse tumor diameter was 53.2 ±â€¯2.76 mm (range: 14-170 mm). Tumors were localized to the pancreatic head (38.1%; 37/97), neck (12.4%; 12/97), body and tail (49.5%; 48/97). There were no significant differences in age of onset, presenting symptoms, and sites between males and females. A significant difference was found in the maximum diameter of SPTP across different age groups. Partial pancreatectomy was performed for patient with tumor ≥ 5 cm, and enucleation was performed when tumor was smaller than 5 cm. Pancreatic fistula was the main complication. Immunohistochemical markers for endocrine, exocrine and epithelial factors were used for a final diagnosis. During a median follow-up of 54 months (range: 7-121 months), 84 patients were alive without evidence of recurrence, and 13 patients were lost to follow-up. CONCLUSION: SPTP surgical resection is a safe procedure with low morbidity and mortality, which is also effective even in the presence of invasiveness and metastases. Accurate initial diagnoses and follow up are essential.

Application of intraoperative transluminal core-biopsy for diagnosis of pancreatic head mass: A single center 15-year experience.

BACKGROUND: Pathology is the gold standard for diagnosis of pancreatic cancer. Preoperative endoscopic ultrasound-guided biopsy is an expensive procedure that is not routine in developing countries, hence a cheap, reliable alternative is required. AIM: To evaluate the effectiveness and safety of a new technique of intraoperative biopsy from pancreatic head mass. METHODS: Patients undergoing intraoperative transluminal core-biopsy (TLCB) for pancreatic head mass from January 2000 to June 2015 were included in this study. Following Kocher's maneuver, a biopsy was taken from the mass through the duodenum transluminally, using a commercial 16G automatic core-biopsy needle. Multiple tissue specimens were obtained for intraoperative frozen section examination. Depending on the pathological results, a decision was taken to either perform pancreaticoduodenectomy, duodenum-preserving pancreatic head resection, bypass surgery, or to just terminate the operation. The malignancy status of the lesion was confirmed by postoperative pathological examination and/or long-term follow-up of the patients. RESULTS: A total of 525 patients were included. Intraoperative pathological reports revealed 436 malignant cases and 89 cases without evidence of malignancy. The sensitivity, specificity, false positive rate, and false negative rate were 97.7%, 100%, 0%, and 2.3%, respectively. Complications occurred in 2 patients. CONCLUSION: TLCB is a quick, safe, effective, and accurate method for intraoperative diagnosis method in patients with pancreatic head mass; it can provide reliable evidence for surgical decision-making.

Predictors of distant metastasis on exploration in patients with potentially resectable pancreatic cancer.

BACKGROUND: Patients with potentially resectable pancreatic ductal adenocarcinoma (PDAC) are frequently found to be unresectable on exploration due to small distant metastasis. This study was to investigate predictors of small distant metastasis in patients with potentially resectable PDAC. METHODS: Patients who underwent surgical exploration for potentially resectable PDAC from 2013 to 2014 were reviewed retrospectively and divided into two groups according to whether distant metastases were encountered on exploration. Then, univariate and multivariate logistic regression analyses were used to identify predictors of distant metastasis. A scoring system to predict distant metastasis of PDAC on exploration was constructed based on the regression coefficient of a multivariate logistic regression model. RESULTS: A total of 235 patients were included in this study. Mean age of the study population was 61.7 ± 10.4 years old. Upon exploration, distant metastases were found intraoperatively in 62 (26.4%) patients, while the remaining 173 were free of distant metastases. Multivariate logistic regression analysis identified that age ≤ 62 years old (p < 0.001), male sex (p = 0.011), tumor size ≥4.0 cm (p < 0.001), alanine aminotransferase level (ALT) < 125 U/L (p < 0.001), and carbohydrate antigen (CA19-9) level ≥ 385 U/mL (p < 0.001) were independent risk factors for occult distant metastasis of PDAC. A preoperative scoring system (0-8 points) for distant metastasis on exploration was constructed using these five factors. The receiver operating characteristic curves showed that the area under the curve of this score was 0.85. A score of 6 points was suggested to be the optimal cut-off value, and the sensitivity and specificity were 85% and 69%, respectively. CONCLUSIONS: Distant metastasis is still frequently encountered on exploration for patients with potentially resectable PDAC. Younger age, male sex, larger tumor size, low ALT level and high CA19-9 level are independent predictors of unexpected distant metastasis on exploration.