Rational design of genotyping nanodevice for HPV subtype distinction.

There are more than 200 subtypes of human papillomavirus (HPV), and high-risk HPVs are a leading cause of cervical cancer. Identifying the genotypes of HPV is significant for clinical diagnosis and cancer control. Herein, we used programmable and modified DNA as the backbone to construct fluorescent genotyping nanodevice for HPV subtype distinction. In our strategy, the dye-labeled single-stranded recognize-DNA (R-DNA) was hybridized with Black Hole Quencher (BHQ) labeled single-stranded link-DNA (L-DNA) to form three functionalized DNA (RL-DNA). Through the extension of polycytosine (poly-C) in L-DNA, three RL-DNAs can be more firmly adsorbed on graphene oxide to construct reliable genotyping nanodevice. The genotyping nanodevice had low background noise since the dual energy transfer, including Förster resonance energy transfer (FRET) from dye to BHQ and the resonance energy transfer (RET) from dye to graphene oxide. Meanwhile, the programmability of DNA allows the proposed strategy to simultaneously and selectively distinguish several HPV subtypes in solution using DNA labeled with different dyes. To demonstrate clinical potential, we show multiplexed assay of HPV subtypes in cervical scrapes, and it has been successfully applied in HPV-DNA analysis in cervical scrapes samples. The genotyping nanodevice could be developed for simultaneous and multiplex analysis of several oligonucleotides in a homogeneous solution by adjusting the recognition sequence, demonstrating its potential application in the rapid screening of multiple biomarkers.

Rational fabrication of a DNA walking nanomachine on graphene oxide surface for fluorescent bioassay.

DNA nanomachines, a delicate type of molecular machines, have been a research hotspot in biotechnology and materials. Here a two-dimensional (2D) DNA walking nanomachine with high working efficiency and low cost was easily assembled by using graphene oxide (GO) as the working platform for precisely fluorescent bioassay through the binding of target hepatitis B virus DNA (HBV-DNA) and the driving force of Exonuclease III (Exo III). The presence of HBV-DNA made continuous Exo III digestion of the FAM-modified DNA (FAM-DNA) in double-strand DNA (dsDNA) part in a burnt-bridge mechanism to output a "one-to-more" amplified signal. Accordingly, a 2D DNA walking nanomachine with simple operation and high cost-performance ratio was constructed. The walking speed of nanomachine was found to be regulated by loading DNA density on single sheet of GO. Furthermore, this nanomachine had low background since the dual energy transfer including fluorescence resonance energy transfer (FRET) from FAM to BHQ1 and the long-range resonance energy transfer (LrRET) from FAM to GO, making the biosensing applications highly promising.

Lighting up of carbon dots for copper(II) detection using an aggregation-induced enhanced strategy.

Carbon dots have promising prospects for analytical and monitoring purposes, but are greatly hindered by the aggregation-induced luminescence quenching owing to the π-π interaction or the non-radiation-excited radical complex formation. Herein hydrothermally prepared orange-yellow fluorescent carbon dots (O-CDs) show an aggregation-induced fluorescence enhancement (AIFE) with Cu2+ owing to the complexation of Cu(II) and the O-CDs. Cu2+ was then sensitively and selectively detected in the linear range from 0.02 to 30 µM with the detection limit of 14 nM, making the detection of Cu2+ in fresh water and E. coli lysate successful, showing that the as-prepared O-CDs could be well applied to the environmental monitoring of heavy metals.

Soft nanoball-encapsulated carbon dots for reactive oxygen species scavenging and the highly sensitive chemiluminescent assay of nucleic acid biomarkers.

The expression level of nucleic acids is closely related to a variety of diseases. Herein, a highly sensitive detection of a nucleic acid based on a CoOOH-luminol chemiluminescence (CL) system without the addition of oxidants was proposed by the toehold-mediated strand displacement reaction (TSDR) and the liposome dual signal amplification strategy with the hybrid probe formed by linking soft nanoballs (SNBs) to magnetic beads (MBs) through DNA hybridization. Inspired by the free radical scavenging effect of the as-prepared carbon dots (CDs), CDs were successfully employed to quench the CL intensity of the CoOOH-luminol system. And the CDs were further encapsulated into liposomes to construct SNBs, which avoided the complex modification of CDs to maintain their original properties, as well as loaded a large number of CDs to scavenge free radicals to achieve signal amplification. Based on this, target DNA (tDNA) could be sensitively detected based on the reduced CL intensity, which achieved a dynamic detection range from 0.1 nM to 20 nM with a limit of detection as low as 59 pM (3σ/k), showing amazing promise in the biosensing of nucleic acid biomarkers.

Nanosurface energy transfer indicating Exo III-propelled stochastic 3D DNA walkers for HIV DNA detection.

DNA-based nanomachines have aroused tremendous interest because of their potential applications in bioimaging, biocomputing, and diagnostic treatment. Herein, we constructed a novel exonuclease III-propelled and signal-amplified stochastic DNA walker that autonomously walked on a spherical particle-based 3D track through a burnt-bridge mechanism, during which nanosurface energy transfer (NSET) occurred between the fluorescent dye modified on hairpin DNA and the surface of gold nanoparticles (AuNPs). As a proof of concept, this stochastic DNA walker achieves prominent detection performance of HIV DNA in the range of 0.05-1.2 nM with a detection limit of 12.7 pM and satisfactory recovery in blood serum, showing high promise in biosensing applications with complicated media.

Discrimination of copper and silver ions based on the label-free quantum dots.

A simple and fast method for copper ions (Cu2+) and silver ions (Ag+) detection was established with cadmium telluride quantum dots (CdTe QDs) as fluorescent probes. In the presence of Cu2+ or Ag+, the fluorescence intensity of TGA-CdTe QD can be significantly quenched, which fitted a linear relationship between the fluorescence quenching degree (F0-F)/F0 and the concentration of metal ions. In this work, the lowest detected concentration for Cu2+ and Ag+ was 35.0 nM and 25.3 nM, respectively. In addition, the differentiation of Cu2+ and Ag+ at different concentrations was realized with the principal component analysis (PCA). Furthermore, Cu2+ was successfully detected in body fluids. This method provides a good potential for copper ions and silver ions detection with simplicity, rapidity, and excellent selectivity.

Dual Energy Transfer-Based DNA/Graphene Oxide Nanocomplex Probe for Highly Robust and Accurate Monitoring of Apoptosis-Related microRNAs.

Fluorescent labeled single-stranded DNA (ssDNA) molecules physisorbed on graphene oxide (GO) have been extensively explored as a useful sensing platform. However, this approach faces challenges when applied to complex biological samples due to heavy nonspecific desorption of nontarget molecules from GO. To overcome this problem, we introduced a capture DNA (cDNA) fragment with a poly adenine (poly-A) extension into the physisorption system that greatly reduces nonspecific desorption and false positive signal due to strong binding between poly-A and GO. Fluorescence from the dye can be effectively quenched by BHQ, which thus provides a second guarantee of anti-interference to avoid possible nonspecific poly-A DNA displacement. As a proof of concept, we have successfully developed a novel DNA-adsorbing GO nanocomplex probe (DNA-GO nanocomplex probe). This probe has a high anti-interference capability and low background due to the presence of both GO and black hole quencher (BHQ) as a dual-quencher that reduces the background in live cell imaging due to resonance energy transfer (RET). We then employed the DNA-GO nanocomplex probe for simultaneous detection of miR-630 and miR-21 and also for simultaneous in situ dynamic monitoring of intracellular miR-630 and miR-21 in apoptotic cells. We discovered that miR-630 expression was up-regulated during the first 120 min. This simple but powerful protocol has great potential in precise detection and imaging of various substances in complex biological samples with improved accuracy.

Nitrogen and phosphorus doped polymer carbon dots as a sensitive cellular mapping probe of nitrite.

Nitrite (NO2 -) is one of the important pollutants in food and the environment, which can seriously endanger the health of human beings. Therefore, detecting nitrite in food, environmental and biological samples is very significant for health monitoring. Herein, polymer carbon dots (PCDs) doped with nitrogen and phosphorus were prepared by polymerization of ascorbic acid (AA) and polyethylenimine (PEI) with phosphoric acid, and exhibited excellent stability, adjustable fluorescence emissions and good biocompatibility. It was found that the PCDs presented a sensitive response to nitrite (NO2 -), and they were successfully applied for NO2 - analysis in water and milk samples, and the dynamic monitoring of nitrite entry into Hep-2 cells.

Portal vein resection and reconstruction with artificial blood vessels is safe and feasible for pancreatic ductal adenocarcinoma patients with portal vein involvement: Chinese center experience.

Evidence shows that portal vein resection (PVR) increase the resectability but does little benefit to overall survival in all pancreatic ductal adenocarcinoma (PDAC) patients. But for patients with portal vein involvement, PVR is the only radical choice. But whether the PDAC patients with portal vein involvement would benefit from radical pancreaticoduodenectomy with PVR or not is controversial. All 204 PDAC patients with portal vein involvement were enrolled in this study [PVR group, n=106; surgical bypass (SB) group, n=52; chemotherapy group, n=46]. Overall survival and prognostic factors were analyzed among three groups. Moreover, a literature review of 13 studies were also conducted. Among 3 groups, patients in PVR group achieved a significant longer survival (median survival: PVR group, 22.83 months; SB group, 7.26 months; chemotherapy group, 10.64 months). Therapy choice [hazard ratio (HR) =1.593, 95% confidence interval (CI) 1.323 to 1.918, P<0.001], body mass index (HR=0.772, 95% CI 0.559 to 0.994, P=0.044) and carbohydrateantigen 19-9 (HR=1.325, 95% CI 1.064 to 1.651, P=0.012) were independent prognostic factors which significantly affected overall survival. Pancreaticoduodenectomy combined with PVR and reconstruct with artificial blood vessels is a safe and an appropriate therapy choice for resectable PDAC patients with portal vein involvement.

Radical resection and enucleation in Chinese adolescents with pancreatic tumors: A 15-year case series.

Pancreatic tumors rarely occur in adolescents, and the appropriateness of radical resection for these patients remains controversial.Medical records were retrospectively reviewed for patients younger than 19 years who underwent radical resection or limited resection (enucleation) between 2000 and 2015. Patient demographics, clinical characteristics, operative details, growth, and survival were analyzed.During the study period, 11 adolescents (mean age, 16.18 years; standard deviation, 1.99; interquartile range, 15.0-18.0) underwent radical resection (n = 7) or enucleation (n = 4) to treat solid pseudopapillary tumors (n = 5), pancreatic neuroendocrine tumors (n = 5), or pancreatic ductal adenocarcinoma (n = 1). None of the 7 patients who underwent radical resection experienced recurrence or serious complications, while 3 of 4 patients who underwent enucleation experienced recurrence (P = 0.02). Recurrence-free survival was slightly longer in patients who underwent radical resection, and this procedure did not appear to affect adolescent growth and development.Radical resection might be safe and effective for adolescents with pancreatic tumors.

Accuracy of routine multidetector computed tomography to identify arterial variants in patients scheduled for pancreaticoduodenectomy.

AIM: To assess the efficacy of cross-sectional multidetector computed tomography (MDCT) imaging without arterial reconstruction to identify aberrant right hepatic artery (RHA) and celiac artery stenosis (CAS) in patients scheduled for pancreaticoduodenectomy. METHODS: Patients with peri-ampullary and pancreatic head tumors who underwent routine preoperative MDCT and subsequent computed tomography (CT) angiography (CTA), conventional angiography or pancreaticoduodenectomy between September 2007 and August 2013 were identified. Retrospective analysis of imaging data was undertaken using CTA, conventional angiographic and surgical findings as the reference standards. The accuracy, sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of MDCT in evaluation of aberrant RHA and CAS were calculated. RESULTS: A group of 458 patients met the inclusion criteria of this study to detect aberrant RHA, and 181 cases were included to identify CAS. Fifty-four (11.8%) patients were confirmed to have aberrant RHA, while 12 (6.6%) patients with CAS were demonstrated. MDCT yielded an accuracy of 98.5%, sensitivity of 96.3% and specificity of 98.8% in the detection of aberrant RHA. The sensitivity, specificity, PPV and NPV of MDCT for detecting CAS were 58.3%, 98.2%, 70% and 97.1%, respectively. CONCLUSION: Routine MDCT is recommended such that surgeons and radiologists be alerted to the importance of arterial variants on preoperative CT scans in patients scheduled for pancreaticoduodenectomy.

Establishment of an orthotopic pancreatic cancer mouse model: cells suspended and injected in Matrigel.

AIM: To establish an orthotopic mouse model of pancreatic cancer that mimics the pathological features of exocrine pancreatic adenocarcinoma. METHODS: Pan02 cells were suspended in low-temperature Matrigel and injected into the parenchyma of pancreatic tails of C57BL/6 mice, with cells suspended in phosphate buffered saline (PBS) serving as a control. Primary and implanted tumors were confirmed pathologically. The rate of tumor formation and intraperitoneal implantation in the two groups were compared at different time points after injection. Leakage and intra-abdominal dispersion of Matrigel and PBS, both dyed with methylene blue, were compared after injection into the parenchyma of the pancreas. We observed adherence and proliferation in Pan02 cells suspended in Matrigel in vitro. We also compared the pathological manifestation of this orthotopic pancreatic cancer model in the head and tails of the pancreas. The characteristics of the origin of epithelial cells and exocrine markers of established orthotopic pancreatic tumors were confirmed using immunohistochemistry. RESULTS: Diluted Matrigel could form a gel drip in the pancreatic parenchyma, effectively preventing leakage from the injection site and avoiding dispersion in the abdominal cavity. Pan02 cells were able to adhere to a dish, proliferate, and migrate in the gel drip. The tumor formation rate in the Matrigel group was 100% at both 2 and 3 wk after injection, whereas it was 25.0% and 37.5% in the PBS group at 2 and 3 wk, respectively (P < 0.05). The intraperitoneal tumor implantation rate was 75.0% in the PBS group after 3 wk of injection, while it was 12.5% in the Matrigel group (P < 0.05). Hepatoduodenal ligament and duodenal invasions with obstructive jaundice and upper digestive obstruction with mesenteric lymph node metastasis were observed in the pancreatic head group. In the pancreatic tail group, spleen and gastric invasion were dominant, leading to retroperitoneal lymph nodes metastasis. Positive immunohistochemical staining of cytokeratin and negative staining of vimentin and chromogranin A confirmed that the orthotopic pancreatic tumor injected with Pan02 cells suspended in Matrigel was of epithelial origin and expressed exocrine markers of cancer. CONCLUSION: This method of low-temperature Matrigel suspension and injection is effective for establishing an orthotopic mouse model of pancreatic cancer.

MicroRNA-218 inhibits cell invasion and migration of pancreatic cancer via regulating ROBO1.

miRNA-218 is a highlighted tumor suppressor and its underlying role in tumor progression is still unknown. Here, we restored the expression of miRNA-218 in pancreatic cancer to clarify the function and potent downstream pathway of miRNA-218. The expressions of both miRNA-218 and its potent target gene ROBO1 were revealed by RT-PCR and western blotting analysis. Transfection of miRNA-218 precursor mimics and luciferase assay were performed to elucidate the regulation mechanism between miRNA-218 and ROBO1. Cells, stably expressing miRNA-218 followed by forced expression of mutant ROBO1, were established through co-transfections of both lentivirus vector and plasmid vector. The cell migration and invasion abilities were evaluated by migration assay and invasion assay respectively. An increased expression of ROBO1 was revealed in cell BxPC-3-LN compared with cell BxPC-3. Elevated expression of miRNA-218 would suppress the expression of ROBO1 via complementary binding to a specific region within 3'UTR of ROBO1 mRNA (sites 971-978) in pancreatic cancer cells. Stably restoring the expression of miRNA-218 in pancreatic cancer significantly downregulated the expression of ROBO1 and effectively inhibited cell migration and invasion. Forced expression of mutant ROBO1 could reverse the repression effects of miRNA-218 on cell migration and invasion. Consequently, miRNA-218 acted as a tumor suppressor in pancreatic cancer by inhibiting cell invasion and migration. ROBO1 was a functional target of miRNA-218's downstream pathway involving in cell invasion and migration of pancreatic cancer.

Is routine drainage necessary after pancreaticoduodenectomy?

With the development of imaging technology and surgical techniques, pancreatic resections to treat pancreatic tumors, ampulla tumors, and other pancreatic diseases have increased. Pancreaticoduodenectomy, one type of pancreatic resection, is a complex surgery with the loss of pancreatic integrity and various anastomoses. Complications after pancreaticoduodenectomy such as pancreatic fistulas and anastomosis leakage are common and significantly associated with patient outcomes. Pancreatic fistula is one of the most important postoperative complications; this condition can cause intraperitoneal hemorrhage, septic shock, or even death. An effective way has not yet been found to avoid the occurrence of pancreatic fistula. In most medical centers, the frequency of pancreatic fistula has remained between 9% and 13%. The early detection and routine drainage of anastomotic fistulas, pancreatic fistulas, bleeding, or other intra-abdominal fluid collections after pancreatic resections are considered as important and effective ways to reduce postoperative complications and the mortality rate. However, many recent studies have argued that routine drainage after abdominal operations, including pancreaticoduodenectomies, does not affect the incidence of postoperative complications. Although inserting drains after pancreatic resections continues to be a routine procedure, its necessity remains controversial. This article reviews studies of the advantages and disadvantages of routine drainage after pancreaticoduodenectomy and discusses the necessity of this procedure.

Multi-centric solid-pseudopapillary neoplasm of the pancreas.

Multi-centric solid-pseudopapillary neoplasm (SPN) of the pancreas is a rare tumor: only 4 cases are reported in the literature. The clinical and pathological features have not yet been fully clarified. We report 3 cases of multi-centric SPN and discuss their clinical presentations and histological and immunohistochemical features, comparing with solitary SPN. Among the total of 7 cases, 6 were female and 1 was male. Patients had nonspecific symptoms at presentation. Tumors were often large and well demarcated with cystic degeneration and clear margin between lumps. Histologically, characteristic pseudopapilla was formed with uniform cells surrounding the delicate blood vessels. Tumor cells were positive for vimentin, synaptophysin, progesterone receptor, and CD10 and demonstrated nuclear localization of ß-catenin. The prognosis of patients was excellent after complete surgical resections. Multi-centric SPN shares similar clinical and pathological features to solitary SPN.

Potential role of soluble VEGFR-1 in antiangiogenesis therapy for cancer.

Antiangiogenesis therapy for cancer may inhibit tumor growth and metastasis when combined with chemotherapy, and has received a great deal of attention over recent years. However, accurate assessments of biological efficacy and toxicity are major hurdles for this approach. Soluble VEGF receptor-1 (sFlt-1) has been reported to have a role in the pathogenesis of preeclampsia, the hallmark of which is similar to the toxicities related to antiangiogenesis therapy. Clinical evidence and animal studies support the hypothesis that sFlt-1 may contribute to hypertension and proteinuria in patients treated with anti-VEGF agents. The intratumoral imbalance between sFlt-1 and VEGF levels correlates with the malignancy grades of tumors, survival and responsiveness to therapy. The therapeutic potential of sFlt-1 as an antiangiogenic agent has been validated by an increasing number of preclinical studies. Furthermore, antiangiogenesis therapy changes the concentration of circulating VEGF, PlGF, sFlt-1, soluble VEGFR-2 and even soluble VEGFR-3, with some of these being identified as potential biomarkers of response and toxicity. All these factors suggest that sFlt-1 may prove invaluable for driving the future development of molecular therapeutics with novel targets and mechanisms of action, and its impact on antiangiogenesis therapy in cancers needs further investigation.

[The thymidine phosphorylase to dihydropyrimidine dehydrogenase ratio in pancreatic cancer].

OBJECTIVE: To determine the contents of thymidine phosphorylase (TP) and dihydropyrimidine dehydrogenase (DPD) in pancreatic cancer to provide a basis for the clinical use of capecitabine in pancreatic cancer patients. METHODS: The contents of TP and DPD in pancreatic cancer and adjacent normal tissues from 20 patients were determined by ELISA and the TP to DPD ratios in the cancer and adjacent normal tissue were compared. RESULTS: TP content was 5- to 283-fold higher in tumor tissue (mean 74-fold) than in the adjacent normal tissue (P < 0.01). DPD in the cancer tissue increased significantly. So did the TP to DPD ratio, when compared to that in normal pancreatic tissue (P < 0.01). CONCLUSION: The increased TP to DPD ratio in pancreatic cancer suggests that capecitabine could be activated by the cancer, these capable of selectively kill the tumor cells.