Silicon nanocavity with a quality factor of 6.7 million fabricated by a CMOS-compatible process.

Here, we report on the increase of the quality-factors of photonic crystal nanocavities fabricated by a CMOS-compatible process. We fabricated nanocavities with the same cavity design but used either a binary photomask or a phase-shift photomask in the photolithography step to assess the impact of the photomask-type on the fabrication accuracy of the air holes. We characterized 62 cavities using time-resolved measurements and the best cavity had a quality-factor of 6.65 × 106. All cavities exhibited a quality-factor larger than 2 million and the overall average was 3.25 × 106. While the estimated magnitude of the scattering loss due to the air hole variations in the 33 cavities fabricated with the phase-shift photomask was slightly lower than that in the 29 cavities fabricated with binary photomask, the phase-shift photomask did not provide a significant improvement in the fabrication accuracy. On average, the scattering loss in these samples is more than 3 times larger than that of nanocavities fabricated using electron-beam lithography, which indicates room for further improvement.

Essential role of Notch/Hes1 signaling in postnatal pancreatic exocrine development.

BACKGROUND: Notch/Hes1 signaling has been shown to play a role in determining the fate of pancreatic progenitor cells. However, its function in postnatal pancreatic maturation is not fully elucidated. METHODS: We generated conditional Hes1 knockout and/or Notch intracellular domain (NICD) overexpression mice in Ptf1a- or Pdx1-positive pancreatic progenitor cells and analyzed pancreatic tissues. RESULTS: Both Ptf1acre/+; Hes1f/f and Ptf1acre/+; Rosa26NICD mice showed normal pancreatic development at P0. However, exocrine tissue of the pancreatic tail in Ptf1acre/+; Hes1f/f mice atrophied and was replaced by fat tissue by 4 weeks of age, with increased apoptotic cells and fewer centroacinar cells. This impaired exocrine development was completely rescued by NICD overexpression in Ptf1acre/+; Hes1f/f; Rosa26NICD mice, suggesting compensation by a Notch signaling pathway other than Hes1. Conversely, Pdx1-Cre; Hes1f/f mice showed impaired postnatal exocrine development in both the pancreatic head and tail, revealing that the timing and distribution of embryonic Hes1 expression affects postnatal exocrine tissue development. CONCLUSIONS: Notch signaling has an essential role in pancreatic progenitor cells for the postnatal maturation of exocrine tissue, partly through the formation of centroacinar cells.

Obstructive Colitis with Minor Perforation Induced by Double Sigmoid Adenocarcinoma.

A 72-year-old women was referred to our hospital because of lower left abdominal pain. Computed tomography showed prominent sigmoid colon dilation and double tumors on both the oral and anal sides. Surgical resection revealed an expanded sigmoid colon involved in double cancer that showed strong adhesion to the surrounding tissues. The pathological findings revealed obstructive colitis and minor perforation in the dilated colon. The minor perforation was considered to have been caused by fecal impaction in the closed cavity between the two tumors, resulting in an increase in colon pressure.

Hes1 Is Essential in Proliferating Ductal Cell-Mediated Development of Intrahepatic Cholangiocarcinoma.

Intrahepatic cholangiocarcinoma (ICC) is frequently driven by aberrant KRAS activation and develops in the liver with chronic inflammation. Although the Notch signaling pathway is critically involved in ICC development, detailed mechanisms of Notch-driven ICC development are still unknown. Here, we use mice whose Notch signaling is genetically engineered to show that the Notch signaling pathway, specifically the Notch/Hes1 axis, plays an essential role in expanding ductular cells in the liver with chronic inflammation or oncogenic Kras activation. Activation of Notch1 enhanced the development of proliferating ductal cells (PDC) in injured livers, while depletion of Hes1 led to suppression. In correlation with PDC expansion, ICC development was also regulated by the Notch/Hes1 axis and suppressed by Hes1 depletion. Lineage-tracing experiments using EpcamcreERT2 mice further confirmed that Hes1 plays a critical role in the induction of PDC and that ICC could originate from PDC. Analysis of human ICC specimens showed PDC in nonneoplastic background tissues, confirming HES1 expression in both PDC and ICC tumor cells. Our findings provide novel direct experimental evidence that Hes1 plays an essential role in the development of ICC via PDC. SIGNIFICANCE: This study contributes to the identification of the cells of origin that initiate ICC and suggests that HES1 may represent a therapeutic target in ICC.

CXCR4 in Tumor Epithelial Cells Mediates Desmoplastic Reaction in Pancreatic Ductal Adenocarcinoma.

Pancreatic ductal adenocarcinoma (PDAC) features abundant stromal cells with an excessive extracellular matrix (ECM), termed the desmoplastic reaction. CXCR4 is a cytokine receptor for stromal cell-derived factor-1 (CXCL12) expressed in PDAC, but its roles in PDAC and the characteristic desmoplastic reaction remain unclear. Here, we generated a mouse model of PDAC with conditional knockout of Cxcr4 (KPC-Cxcr4-KO) by crossing Cxcr4 flox mice with Pdx1-Cre;KrasLSL-G12D/+;Trp53LSL-R172H/+ (KPC-Cxcr4-WT) mice to assess the development of pancreatic intraepithelial neoplasia (PanIN) and pancreatic cancers. Tumor cell characteristics of those two types were analyzed in vitro. In addition, CXCR4 expression in human pancreatic cancer specimens was evaluated by IHC staining. In KPC-Cxcr4-KO mice, the number and pathologic grade of PanIN lesions were reduced, but the frequency of pancreatic cancers did not differ from that in KPC-Cxcr4-WT mice. The pancreatic tumor phenotype in KPC-Cxcr4-KO mice was significantly larger and undifferentiated, characterized by abundant vimentin-expressing cancer cells, significantly fewer fibroblasts, and markedly less deposition of ECM. In vitro, KPC-Cxcr4-KO tumor cells exhibited higher proliferative and migratory activity than KPC-Cxcr4-WT tumor cells. Myofibroblasts induced invasion activity in KPC-Cxcr4-WT tumor cells, showing an epithelial-mesenchymal interaction, whereas KPC-Cxcr4-KO tumor cells were unaffected by myofibroblasts, suggesting their unique nature. In human pancreatic cancer, undifferentiated carcinoma did not express CXCR4 and exhibited histologic and IHC features similar to those in KPC-Cxcr4-KO mice. In summary, the CXCL12/CXCR4 axis may play an important role in the desmoplastic reaction in PDAC, and loss of CXCR4 induces phenotype changes in undifferentiated carcinoma without a desmoplastic reaction. SIGNIFICANCE: The current study uncovers CXCR4 as a key regulator of desmoplastic reaction in PDAC and opens the way for new therapeutic approaches to overcome the chemoresistance in patients with PDAC.

Rb and p53 Execute Distinct Roles in the Development of Pancreatic Neuroendocrine Tumors.

Pancreatic neuroendocrine tumors (PanNET) were classified into grades (G) 1 to 3 by the World Health Organization in 2017, but the precise mechanisms of PanNET initiation and progression have remained unclear. In this study, we used a genetically engineered mouse model to investigate the mechanisms of PanNET formation. Although pancreas-specific deletion of the Rb gene (Pdx1-Cre;Rbf/f ) in mice did not affect pancreatic exocrine cells, the α-cell/ß-cell ratio of islet cells was decreased at 8 months of age. During long-term observation (18-20 months), mice formed well-differentiated PanNET with a Ki67-labeling index of 2.7%. In contrast, pancreas-specific induction of a p53 mutation (Pdx1-Cre;Trp53R172H ) had no effect on pancreatic exocrine and endocrine tissues, but simultaneous induction of a p53 mutation with Rb gene deletion (Pdx1-Cre;Trp53R172H;Rb f/f ) resulted in the formation of aggressive PanNET with a Ki67-labeling index of 24.7% over the short-term (4 months). In Pdx1-Cre;Trp53R172H;Rbf/f mice, mRNA expression of Pten and Tsc2, negative regulators of the mTOR pathway, significantly decreased in the islet cells, and activation of the mTOR pathway was confirmed in subsequently formed PanNET. Thus, by manipulating Rb and p53 genes, we established a multistep progression model from dysplastic islet to indolent PanNET and aggressive metastatic PanNET in mice. These observations suggest that Rb and p53 have distinct roles in the development of PanNET. SIGNIFICANCE: Pancreas-specific manipulation of Rb and p53 genes induced malignant transformation of islet cells, reproducing stepwise progression from microadenomas to indolent (grade 1) and subsequent aggressive PanNETs (grade 2-3).

Hes1 plays an essential role in Kras-driven pancreatic tumorigenesis.

Most pancreatic ductal adenocarcinoma (PDAC) develops from pancreatic epithelial cells bearing activating mutant KRAS genes through precancerous lesions, i.e. acinar-to-ductal metaplasia (ADM) and pancreatic intraepithelial neoplasia (PanIN). During pancreatic tumorigenesis, Hes1 expression starts with the transition from acinar cells to ADM, and continues during PanIN and PDAC formation, but the role of Hes1 in pancreatic tumorigenesis is not fully elucidated. Here we show that Hes1 plays an essential role in the initiation and progression of KRAS-driven pancreatic tumorigenesis. In vitro, activation of MAPK signaling due to EGF or mutant KRAS activation induced sustained Hes1 expression in pancreatic acinar cells. In vivo, acinar cell-specific activation of mutant KRAS by Elastase1-CreERT2;KrasG12D induced ADM/PanIN formation with Hes1 expression in mice, and genetic ablation of Hes1 in these mice dramatically suppressed PanIN formation. Gene expression analysis and lineage tracing revealed that Hes1 regulates acinar-to-ductal reprogramming-related genes and, in a Hes1-deficient state, mutant Kras-induced ADM could not progress into PanIN, but re-differentiated into acinar cells. In the Elastase1-CreERT2;KrasG12D;Trp53R172H mouse PDAC model, genetic ablation of Hes1 completely blocked PDAC formation by keeping PanIN lesions in low-grade conditions, in addition to reducing the occurrence of PanIN. Together, these findings indicate that mutant KRAS-induced Hes1 plays an essential role in PDAC initiation and progression by regulating acinar-to-ductal reprogramming-related genes.

Determination of Minor and Trace Metals in Aluminum and Aluminum Alloys by ICP-AES; Evaluation of the Uncertainty and Limit of Quantitation from Interlaboratory Testing.

Minor and trace metals in aluminum and aluminum alloys have been determined by inductively coupled plasma atomic emission spectrometry (ICP-AES) as an interlaboratory testing toward standardization. The trueness of the measured data was successfully investigated to improve the analytical protocols, using certified reference materials of aluminum. Their precision could also be evaluated, feasible to estimate the uncertainties separately. The accuracy (trueness and precision) of the data were finally in good agreement with the certified values and assigned uncertainties. Repeated measurements of aluminum solutions with different concentrations of the analytes revealed the relative standard deviations of the measurements with concentrations, thus enabling their limits of quantitation. They differed separately and also showed slightly higher values with an aluminum matrix than those without one. In addition, the upper limit of the detectable concentration of silicon with simple acid digestion was estimated to be 0.03 % in the mass fraction.

Pathogenicity of IgG in patients with IgG4-related disease.

OBJECTIVE: IgG4-related disease (IgG4-RD) is a systemic disease characterised by elevated serum IgG4 and IgG4-positive lymphoplasmacytic infiltration in the affected tissues. The pathogenic role of IgGs, including IgG4, in patients with IgG4-RD, however, is unknown. DESIGN: We examined the pathogenic activity of circulating IgGs in patients with IgG4-RD by injecting their IgGs into neonatal male Balb/c mice. Binding of patient IgGs to pancreatic tissue was also analysed in an ex vivo mouse organ culture model and in tissue samples from patients with autoimmune pancreatitis (AIP). RESULTS: Subcutaneous injection of patient IgG, but not control IgG, resulted in pancreatic and salivary gland injuries. Pancreatic injury was also induced by injecting patient IgG1 or IgG4, with more destructive changes induced by IgG1 than by IgG4. The potent pathogenic activity of patient IgG1 was significantly inhibited by simultaneous injection of patient IgG4. Binding of patient IgG, especially IgG1 and IgG4, to pancreatic tissue was confirmed in both the mouse model and AIP tissue samples. CONCLUSIONS: IgG1 and IgG4 from patients with IgG4-RD have pathogenic activities through binding affected tissues in neonatal mice.

Activation-Induced Cytidine Deaminase Contributes to Pancreatic Tumorigenesis by Inducing Tumor-Related Gene Mutations.

Pancreatic ductal adenocarcinoma (PDAC) develops via an accumulation of various gene mutations. The mechanism underlying the mutations in PDAC development, however, is not fully understood. Recent insight into the close association between the mutation pattern of various cancers and specific mutagens led us to investigate the possible involvement of activation-induced cytidine deaminase (AID), a DNA editing enzyme, in pancreatic tumorigenesis. Our immunohistochemical findings revealed AID protein expression in human acinar ductal metaplasia, pancreatic intraepithelial neoplasia, and PDAC. Both the amount and intensity of the AID protein expression increased with the progression from precancerous to cancerous lesions in human PDAC tissues. To further assess the significance of ectopic epithelial AID expression in pancreatic tumorigenesis, we analyzed the phenotype of AID transgenic (AID Tg) mice. Consistent with our hypothesis that AID is involved in the mechanism of the mutations underlying pancreatic tumorigenesis, we found precancerous lesions developing in the pancreas of AID Tg mice. Using deep sequencing, we also detected Kras and c-Myc mutations in our analysis of the whole pancreas of AID Tg mice. In addition, Sanger sequencing confirmed the presence of Kras, c-Myc, and Smad4 mutations, with the typical mutational footprint of AID in precancerous lesions in AID Tg mice separated by laser capture microdissection. Taken together, our findings suggest that AID contributes to the development of pancreatic precancerous lesions by inducing tumor-related gene mutations. Our new mouse model without intentional manipulation of specific tumor-related genes provides a powerful system for analyzing the mutations involved in PDAC.

Nanocavities at the surface of three-dimensional photonic crystals.

We investigate nanocavities at the surface of three-dimensional (3D) photonic crystals, where the polarization-independent surface-mode gap can be utilized. We consider the formation of various nanocavities by introducing artificial defects utilizing the 3D structures around the surface and discuss the possibilities for increasing the Q-factors of the surface nanocavities with TE-like polarization based on the advanced designs of donor-type defects. We also introduce the design of acceptor-type defects and show that TM-like nanocavities are obtained. We then fabricate the designed nanocavities and examine their resonant characteristics; we successfully demonstrate TE-like nanocavities with Q-factors of ~40,000, which is four-times higher than previous surface cavities and as high as that of the cavities embedded inside 3D photonic crystals. TM-like nanocavities with Q-factors of ~22,000 are also demonstrated for the first time.

Risk of cancer in patients with autoimmune pancreatitis.

OBJECTIVES: Although simultaneous occurrences of autoimmune pancreatitis (AIP) and cancer are occasionally observed, it remains largely unknown whether cancer and AIP occur independently or these disorders are interrelated. The aim of this study was to examine the relationship between AIP and cancer. METHODS: We conducted a multicenter, retrospective cohort study. One hundred and eight patients who met the Asian diagnostic criteria for AIP were included in the study. We calculated the proportion, standardized incidence ratio (SIR), relative risk, and time course of cancer development in patients with AIP. We also analyzed the clinicopathological characteristics of AIP patients with cancer in comparison with those without cancer. RESULTS: Of the 108 AIP patients, 18 cancers were found in 15 patients (13.9%) during the median follow-up period of 3.3 years. The SIR of cancer was 2.7 (95% confidence interval (CI) 1.4-3.9), which was stratified into the first year (6.1 (95% CI 2.3-9.9)) and subsequent years (1.5 (95% CI 0.3-2.8)) after AIP diagnosis. Relative risk of cancer among AIP patients at the time of AIP diagnosis was 4.9 (95% CI 1.7-14.9). In six of eight patients whose cancer lesions could be assessed before corticosteroid therapy for AIP, abundant IgG4-positive plasma cell infiltration was observed in the cancer stroma. These six patients experienced no AIP relapse after successful cancer treatment. CONCLUSIONS: Patients with AIP are at high risk of having various cancers. The highest risk for cancer in the first year after AIP diagnosis and absence of AIP relapse after successful treatment of the coexisting cancers suggest that AIP may develop as a paraneoplastic syndrome in some patients.

Therapeutic endoscopy for stenotic pancreatodigestive tract anastomosis after pancreatoduodenectomy (with videos).

BACKGROUND: Pancreatodigestive tract anastomotic site stenosis is a problematic complication after pancreatoduodenectomy. OBJECTIVE: We evaluated the feasibility and efficacy of endoscopic treatments for a stenotic pancreatodigestive tract anastomosis. DESIGN: Retrospective study. SETTING: Endoscopic units of a university-affiliated hospital and a general hospital. PATIENTS: Fourteen patients with recurrent pancreatitis (n=10) and pancreatic fluid fistula (n=4) after anatomy-altering surgery with pancreatodigestive tract anastomosis. INTERVENTIONS: The initial ERCP included obtaining a pancreatogram, introducing a 0.025-inch guidewire through the anastomosis, along which a 5F plastic stent or nasopancreatic drain was inserted. If initial ERCP failed, we attempted EUS-guided rendezvous, with a guidewire passed antegrade from the main pancreatic duct across the stenotic anastomosis. MAIN OUTCOME MEASUREMENTS: Rates of successful intervention and clinical relief. RESULTS: The initial intervention was successfully achieved in 6 of 14 patients (38%). Of the 6 patients with successful therapeutic endoscopies, 4 (66.7%) and 2 (25.0%) had undergone a previous pancreatogastrostomy or pancreatojejunostomy, respectively. Eight patients with an initial unsuccessful intervention successfully underwent a second intervention using an EUS-guided or US-guided rendezvous method. Finally, stenosis was relieved in all patients with either the retrograde placement of a pancreatic duct stent across the stenosis of an anastomotic site or antegrade percutaneous bougienage of the stenotic anastomosis. LIMITATIONS: Small sample size and lack of control patients. CONCLUSIONS: Endoscopic treatment of stenotic pancreatodigestive tract anastomosis for transanastomotic pancreatic juice drainage is safe and feasible.

Surface modes of three-dimensional photonic crystals constructed using a top-down approach.

We have investigated the photonic modes at the surface of three-dimensional photonic crystals fabricated using a top-down approach involving two-step etching at angles of ± 45°. Numerical simulations revealed the properties of these surface modes, including their polarization characteristics and dependence on the surface structure. The formation of surface modes was experimentally demonstrated using an evanescent-coupling method and agreed well with the simulations.

Percutaneous pancreatic-duct puncture with rendezvous technique can treat stenotic pancreaticojejunostomy.

Stenotic pancreatico-enteric anastomosis is one of the serious late complications after a pancreaticoduodenectomy. We report a case of stenotic pancreaticojejunostomy with a pancreatic juice fistula drained externally, which was treated using percutaneous procedures combined with a rendezvous method. A 77-year-old woman was referred to our hospital for an endoscopic treatment to remove a percutaneous drainage tube from a fluid collection due to pancreatic juice fistula. She had undergone pylorus-preserving pancreatoduodenectomy with Roux-en-Y reconstruction due to duodenal carcinoma of Vater's papilla 1 year before the referral to our hospital. Soon after the operation, she had developed a fluid collection adjacent to the anastomosis due to pancreatic juice fistulas and subsequently had undergone its percutaneous drainage. After admission, we tried to dilate the stenotic anastomosis with an endoscopic procedure from the anastomosed jejunal lumen, using an oblique-viewing endoscope. The endoscope reached a portion of the anastomosis, but did not allow us to visualize the entire anastomosis. We punctured the main pancreatic duct under ultrasonography and fluoroscopy, and advanced the needle into the anastomosed jejunum through the stenotic anastomosis. After putting a guidewire into the anastomosed jejunum through the needle, we introduced an oblique-viewing endoscope into the anastomosed jejunum and caught hold of the guidewire using grasping forceps. Maintaining tension on the guidewire with a slight pulling force, with some effort we were able to place a 5-Fr drainage catheter into the jejunum percutaneously and through the anastomosis via the main pancreatic duct. Three weeks after these procedures, we performed balloon dilation of the anastomosis. One week after balloon dilation, removed the percutaneous catheter.

Phenotypic variability of the homozygous IVS3+2T>C mutation in the serine protease inhibitor Kazal type 1 (SPINK1) gene in patients with chronic pancreatitis.

Chronic pancreatitis (CP) is a progressive inflammatory disease that eventually results in the impairment of exocrine and endocrine functions of the pancreas. Recent studies have shown an association between mutations in the serine protease inhibitor Kazal type 1 (SPINK1) gene and CP. SPINK1 provides the first line of defense against prematurely activated trypsinogen by physically blocking the active site of trypsin. The IVS3+2T>C (c.194+2T>C) mutation is a loss-of-function splicing mutation; it affects the consensus splicing donor site in intron 3 and may cause the skipping of the entire exon 3, where the trypsin-binding site is located. We report here three CP patients carrying this mutation in a homozygous form, with no noticeable family history of pancreatitis. The first patient is a 25-year-old male with juvenile-onset idiopathic CP. He suffered from repeated attacks of pancreatitis since 5 years old and underwent pancreatico-jejunostomy. He complained of epigastralgia, and was diagnosed as obstructive pancreatitis in the area of the accessory pancreatic duct. The second patient is a 75-year-old male with alcoholic CP. He did not have apparent attacks of pancreatitis, but had numerous calcifications throughout the pancreas and confirmed exocrine failure and diabetes mellitus. The last patient is a 44-year-old female with late-onset idiopathic CP. She suffered from repeated attacks of pancreatitis since 32 years old. She had numerous stones in the main pancreatic duct in the pancreas head and confirmed exocrine failure. The clinical courses of these patients are apparently different, indicating the phenotypic variability of the SPINK1 IVS3+2T>C mutation-associated CP.

Pancreatic pseudocysts in post-gastrectomy patients treated via the duodenal minor papilla with an oblique-viewing endoscope.

Endoscopic retrograde cholangiopancreatography (ERCP) in patients after Billroth II or Roux-en-Y reconstruction is challenging because of difficulties in insertion of the endoscope into the afferent loop, which is a great distance away from the papilla of Vater, and cannulation into the desired duct from a reverse position. To facilitate ERCP, various endoscopes have been selected according to operator preference. Previously, we reported that an oblique-viewing endoscope (XK-200; Olympus, Tokyo, Japan) can contribute to successful performance of ERCP and associated procedures in Billroth II gastrectomy patients. We report here our experience with two post-gastrectomy patients with chronic pancreatitis who were treated with an oblique-viewing endoscope from the minor papilla.

[A case of severe alcoholic hepatitis successfully treated by granulocytapheresis].

A 34-year-old woman was admitted because of severe liver dysfunction due to excessive alcohol intake. Liver biopsy performed on the fifth day showed liver tissue with marked granulocyte infiltration and pericellular fibrosis. As there were no improvements in white blood cell count and serum total bilirubin levels despite the use of corticosteroids and plasma exchange, hemodiafiltration, we performed granulocytapheresis (GCAP). Peripheral white blood cells decreased from just after GCAP. Her condition remained stable and she was discharged on the 54th day. We suggest that GCAP can be recommended as an effective therapy for severe alcoholic hepatitis.