Tadashi Sato

Small invasive ductal adenocarcinoma of the pancreas associated with lymphoplasmacytic sclerosing pancreatitis

An asymptomatic 59‐year‐old man underwent pancreatoduodenectomy for a pancreatic mass that was discovered during a health check‐up. Histopathology indicated typical features of lymphoplasmacytic sclerosing pancreatitis (LPSP) or autoimmune pancreatitis along with the presence of abundant IgG4‐positive plasma cells throughout the mass. A small invasive ductal adenocarcinoma was observed in the center of the area affected by LPSP. The present case suggests that LPSP may be closely related to carcinogenesis of the pancreas.

Ultrastructural and functional development of macrophages in the dermal tissue of rat fetuses

SummaryAfter about 12 days of gestation, fetal macrophages begin to appear in the subepidermal mesenchyme of rat fetuses. The macrophages are ultrastructurally characterized by cytoplasmic vacuoles, abundant polyribosomes and long filopodia. Immunocytologically, they possess Fc and complement (C3) receptors on the cell surface and are capable of immune phagocytosis, Latex or carbon phagocytosis, and glass adherence. From 15 days of gestation, lysosomal granules and miropinocytic vesicles gradually develop, together with an enlargement of Golgi complexes, whereas the number of polysomes and the number and size of cytoplasmic vacuoles are gradually reduced when gestation ends. Finally, the macrophages become amoeboid. Non-specific esterase and endogenous peroxidase activities are always absent in these macrophages. In culture experiments with cell suspensions prepared from the mesenchyme, fetal macrophages show a similar maturation process. Autoradiography with 3H-thymidine demonstrates a high proliferative capacity of the macrophages, particularly during the fetal stage.

DICKKOPF-4 and -2 genes are upregulated in human colorectal cancer.

To comprehensively screen for genetic events underlying colorectal cancer, we performed suppression subtraction hybridization analysis on an advanced colon cancer. Because Dickkopf‐4, a member of the Dickkopf family acting as a Wnt‐signaling modulator, was identified as one of the upregulated genes in this specimen, we investigated expression profiles of all the Dickkopf family members in 55 colorectal tumors (21 cancers and 34 adenomas). We also investigated mechanisms regulating the expression of Dickkopf‐4 in these cancers in vitro and in vivo. Compared with normal adjacent mucosae, Dickkopf‐4 (median 27.4, P < 0.01) and ‐2 (median 51.4, P < 0.01) were strongly expressed in colorectal cancers. The level of Dickkopf‐4 was positively correlated with fibroblast growth factor‐20 (rs = 0.61, P = 0.00017), a representative β‐catenin transcriptional target gene, and with the degree of nuclear accumulation of β‐catenin in colorectal tumors. Dickkopf‐4 was induced by activated β‐catenin in vitro. Reciprocally, recombinant Dickkopf‐4 significantly inhibited T‐cell factor/lymphocyte enhancer factor reporter activity stimulated by recombinant Wnt3a in human embryonic kidney 293 cells. We conclude that Dickkopf‐4 and ‐2 are significantly upregulated in most colorectal tumors, and that Dickkopf‐4 upregulation reflects activation of the Wnt/canonical pathway. (Cancer Sci 2009; 100: 1923–1930)

Deep sequencing of cancer-related genes revealed GNAS mutations to be associated with intraductal papillary mucinous neoplasms and its main pancreatic duct dilation.

Background To clarify the genetic mutations associated with intraductal papillary mucinous neoplasms (IPMN) and IPMN-related pancreatic tumours, we conducted cancer-related gene profiling analyses using pure pancreatic juice and resected pancreatic tissues. Methods Pure pancreatic juice was collected from 152 patients [nine with a normal pancreas, 22 with chronic pancreatitis (CP), 39 with pancreatic ductal adenocarcinoma (PDAC), and 82 with IPMN], and resected tissues from the pancreas were collected from 48 patients (six IPMNs and 42 PDACs). The extracted DNA was amplified by multiplexed polymerase chain reaction (PCR) targeting 46 cancer-related genes containing 739 mutational hotspots. The mutations were analysed using a semiconductor-based DNA sequencer. Results Among the 46 cancer-related genes, KRAS and GNAS mutations were most frequently detected in both PDAC and IPMN cases. In pure pancreatic juice, GNAS mutations were detected in 7.7% of PDAC cases and 41.5% of IPMN cases (p<0.001 vs. others). All PDAC cases with GNAS mutations (nu200a=u200a3) were accompanied by IPMN. Multivariate analysis revealed that GNAS mutations in IPMN cases were associated with dilated main pancreatic ducts (MPD, pu200a=u200a0.016), while no statistically independent associations with clinical variables were observed for KRAS mutations. In the resected pancreatic tissues, GNAS mutations were detected in 50% of PDAC cases concomitant with IPMN, 33.3% of PDAC cases derived from IPMN, and 66.7% of IPMN cases, while no GNAS mutations were detected in cases of PDAC without IPMN. Conclusions The GNAS mutation was specifically found in the cases with IPMN and it was speculated that some PDACs might be influenced by the concomitant but separately-located IPMN in their pathogenic mechanism. Furthermore, the GNAS mutation was significantly associated with MPD dilatation in IPMN cases, suggesting its role in mucus hypersecretion.

Hepatocellular carcinoma risk assessment using gadoxetic acid-enhanced hepatocyte phase magnetic resonance imaging.

To investigate whether the patients with hypovascular liver nodules determined on the arterial phase and hypointensity on the hepatocyte phase gadoxetic acid‐enhanced magnetic resonance imaging (hypovascular hypointense nodules) are at increased risk of hepatocarcinogenesis, we assessed subsequent typical hepatocellular carcinoma (HCC) development at any sites of the liver with and without such nodules.

Secretin-stimulating MRCP in patients with pancreatobiliary maljunction and occult pancreatobiliary reflux: direct demonstration of pancreatobiliary reflux

We propose the hypothesis that the enlargement of the common bile duct (CBD) or gallbladder (GB) that is occasionally demonstrated on magnetic resonance cholangiopancreatography (MRCP) after secretin stimulation is caused by pancreatobiliary reflux. Recently, occult pancreatobiliary reflux (OPR) has been demonstrated in patients without morphological pancreatobiliary maljunction (MPBM). The aim of this study was to evaluate the efficacy of secretin-stimulating MRCP (SMRCP) in the diagnosis of pancreatobiliary reflux. The study included 14 patients with MPBM and 32 patients with a normal pancreatobiliary junction. OPR was evaluated by bile collection and diagnosed in seven of the 32 patients. All the patients underwent SMRCP; the related findings were considered positive when enlargement of the CBD or GB was observed. Positive findings on SMRCP were observed in all MPBM patients. In the patients with normal pancreatobiliary junction, there was significant difference between the mean amylase levels in the patients with positive and negative SMRCP findings (mean, 4,755.7 and 29.7xa0IU/l). The sensitivity and specificity of SMRCP for diagnosing OPR was 85.7% and 68.0%, respectively. SMRCP provides a non invasive method for excluding PBR and can identify patients who could benefit from bile duct sampling to diagnose OPR.

Deep Sequencing and Phylogenetic Analysis of Variants Resistant to Interferon-Based Protease Inhibitor Therapy in Chronic Hepatitis Induced by Genotype 1b Hepatitis C Virus

ABSTRACT Because of recent advances in deep sequencing technology, detailed analysis of hepatitis C virus (HCV) quasispecies and their dynamic changes in response to direct antiviral agents (DAAs) became possible, although the role of quasispecies is not fully understood. In this study, to clarify the evolution of viral quasispecies and the origin of drug-resistant mutations induced by interferon (IFN)-based protease inhibitor therapy, the nonstructural-3 (NS3) region of genotype 1b HCV in 34 chronic hepatitis patients treated with telaprevir (TVR)/pegylated interferon (PEG-IFN)/ribavirin (RBV) was subjected to a deep sequencing study coupled with phylogenetic analysis. Twenty-six patients (76.5%) achieved a sustained viral response (SVR), while 8 patients did not (non-SVR; 23.5%). When the complexity of the quasispecies was expressed as the mutation frequency or Shannon entropy value, a significant decrease in the IFNL3 (rs8099917) TT group and a marginal decrease in the SVR group were found soon (12 h) after the introduction of treatment, whereas there was no decrease in the non-SVR group and no significant decrease in mutation frequency in the IFNL3 TG/GG group. In the analysis of viral quasispecies composition in non-SVR patients, major populations greatly changed, accompanied by the appearance of resistance, and the compositions were unlikely to return to the pretreatment composition even after the end of therapy. Clinically TVR-resistant variants were observed in 5 non-SVR patients (5/8, 62.5%), all of which were suspected to have acquired resistance by mutations through phylogenetic analysis. In conclusion, results of the study have important implications for treatment response and outcome in interferon-based protease inhibitor therapy. IMPORTANCE In the host, hepatitis C virus (HCV) consists of a variety of populations (quasispecies), and it is supposed that dynamic changes in quasispecies are closely related to pathogenesis, although this is poorly understood. In this study, recently developed deep sequencing technology was introduced, and changes in quasispecies associated with telaprevir (TVR)/pegylated interferon (PEG-IFN)/ribavirin (RBV) triple therapy and their clinical significance were investigated extensively by phylogenetic tree analysis. Through this study, the associations among treatment response, changes in viral quasispecies complexity in the early stage of treatment, changes in the quasispecies composition, and origin of TVR-resistant variant HCV were elucidated.

VacA, the vacuolating cytotoxin of Helicobacter pylori, binds to multimerin 1 on human platelets

Platelets were activated under the infection with H. pylori in human and mice. We investigated the role of VacA, an exotoxin released by H. pylori in this context. Acid-activated VacA, but not heated VacA, induced platelet CD62P expression. However, VacA reacted with none of the alleged VacA receptors present on platelet membranes. We therefore analyzed VacA associated proteins obtained through VacA affinity chromatography, using MALDI-TOF-MS. Multimerin1 was detected in two consecutive experiments, as the binding protein for VacA. Plasmon resonance confirmed their binding, and dot blot analysis revealed that the peptide sequence AA 321-340 of multimerin 1 is the binding site for VacA. In conclusion, we propose a new interaction between multimerin1 and VacA , which may give another insight into H. pylori-induced platelet activations under H. pylori infection.

Partially covered metal stents have longer patency than uncovered and fully covered metal stents in the management of distal malignant biliary obstruction: a retrospective study

BackgroundSelf-expandable metal stents (SEMSs) are widely used for malignant biliary obstructions. Nitinol-covered SEMSs have been developed to improve stent patency. Currently, SEMSs may be uncovered, partially covered, or fully covered; however, there is no consensus on the best stent type for the management of malignant distal biliary obstruction (MDBO).MethodsPatients with unresectable MDBO receiving SEMS (Wallflex™) were retrospectively analyzed. Time to recurrent biliary obstruction (TRBO) and survival time were compared among the three types of SEMSs. Univariate and multivariate analyses were performed to identify risk factors for stent dysfunction.ResultsIn total, 101 patients received SEMSs for unresectable MDBO (44 uncovered, 28 partially covered, and 29 fully covered SEMSs). Median survival time was 200, 168, and 276xa0days in the uncovered, partially covered, and fully covered SEMSs groups, respectively. There were no differences in survival among the three groups. Median TRBO was 199, 444, and 194xa0days in the uncovered, partially covered, and fully covered SEMSs groups, respectively. Partially covered SEMSs had longer TRBO than uncovered (pxa0=xa00.013) and fully covered (pxa0=xa00.010) SEMSs. Tumor ingrowth occurred only with uncovered SEMSs and stent migration occurred only with fully covered SEMSs. Multivariate analyses confirmed that partially covered SEMSs have lower risk of dysfunction.ConclusionsPartially covered SEMSs with a proximal uncovered flared end have longer patency than uncovered and fully covered SEMSs by preventing tumor ingrowth and stent migration.

Evaluation of an e-learning system for diagnosis of gastric lesions using magnifying narrow-band imaging: a multicenter randomized controlled study

Background and study aimu2002Magnifying narrow-band imaging (M-NBI) is useful for the accurate diagnosis of early gastric cancer (EGC). However, acquiring skill at M-NBI diagnosis takes substantial effort. An Internet-based e-learning system to teach endoscopic diagnosis of EGC using M-NBI has been developed. This study evaluated its effectiveness. Participants and methodsu2002This study was designed as a multicenter randomized controlled trial. We recruited endoscopists as participants from all over Japan. After completing Test 1, which consisted of M-NBI images of 40 gastric lesions, participants were randomly assigned to the e-learning or non-e-learning groups. Only the e-learning group was allowed to access the e-learning system. After the e-learning period, both groups received Test 2.u200aThe analysis set was participants who scored <u200a80u200a% accuracy on Test 1.u200aThe primary end point was the difference in accuracy between Test 1 and Test 2 for the two groups. Resultsu2002A total of 395 participants from 77 institutions completed Test 1 (198 in the e-learning group and 197 in the non-e-learning group). After the e-learning period, all 395 completed Test 2.u200aThe analysis sets were e-learning group: nu200a=u200a184; and non-e-learning group: nu200a=u200a184.u200aThe mean Test 1 score was 59.9u200a% for the e-learning group and 61.7u200a% for the non-e-learning group.u200aThe change in accuracy in Test 2 was significantly higher in the e-learning group than in the non-e-learning group (7.4 points vs. 0.14 points, respectively; Pu200a<u200a0.001). Conclusion This study clearly demonstrated the efficacy of the e-learning system in improving practitioners capabilities to diagnose EGC using M-NBI.Trial registered at University Hospital Medical Information Network Clinical Trials Registry (UMIN000008569).