High-cost, high-capacity backbone for global brain communication

Network studies of human brain structural connectivity have identified a specific set of brain regions that are both highly connected and highly central. Recent analyses have shown that these putative hub regions are mutually and densely interconnected, forming a "rich club" within the human brain. Here we show that the set of pathways linking rich club regions forms a central high-cost, high-capacity backbone for global brain communication. Diffusion tensor imaging (DTI) data of two sets of 40 healthy subjects were used to map structural brain networks. The contributions to network cost and communication capacity of global cortico-cortical connections were assessed through measures of their topology and spatial embedding. Rich club connections were found to be more costly than predicted by their density alone and accounted for 40% of the total communication cost. Furthermore, 69% of all minimally short paths between node pairs were found to travel through the rich club and a large proportion of these communication paths consisted of ordered sequences of edges ("path motifs") that first fed into, then traversed, and finally exited the rich club, while passing through nodes of increasing and then decreasing degree. The prevalence of short paths that follow such ordered degree sequences suggests that neural communication might take advantage of strategies for dynamic routing of information between brain regions, with an important role for a highly central rich club. Taken together, our results show that rich club connections make an important contribution to interregional signal traffic, forming a central high-cost, high-capacity backbone for global brain communication.     

2009-2010 novel influenza A (H1N1) vaccination coverage in the Republic of Korea

This study aimed to assess vaccination coverage for novel influenza A (H1N1) in Korea using a immunization registry system as the data source. Vaccination coverage was found to be 26.1% for the total population and 54.4% for priority groups targeted by a national vaccination campaign between October 27, 2009, to March 31, 2010. The factors associated with increased coverage were rapid vaccination and free vaccination; these factors may need to be considered in future pandemics.     

Factors influencing jaundice-free survival with the native liver in post-portoenterostomy biliary atresia patients: Results from a single institution

Purpose

We reviewed post-portoenterostomy (PE) biliary atresia (BA) patients who became “jaundice-free” (JF; total bilirubin (T-bil) ≤ 1.2 mg/dL) to determine factors associated with survival with the native liver (SNL).

Methods

We reviewed 76 BA patients treated by PE at our institute between 1989, when liver transplantation (LTx) became available in Japan, and 2012, prospectively. Of these, 60 who became JF and remained JF were divided into two groups, SNL (n = 44) and LTx (n = 16). Age and weight at PE, pre- and post-PE T-bil, AST, γ-GT, time taken to become JF, corticosteroid requirements, incidence of cholangitis, and micro-bile duct size were compared between the two groups.

Results

The SNL patients became JF significantly earlier: 58 vs. 115 days (p < .05). Corticosteroid requirement, cholangitis, and postoperative AST/γ-GT were significantly lower in the SNL patients (p < .05). SNL was significantly higher if patients became JF ≤ 60 days post-PE (p < .01). LTx was performed from 0.5 to 11 years post-PE (mean = 3.4). All patients who had cholangitis within 3 months of PE eventually required LTx (p < .05).

Conclusions

Becoming JF ≤ 60 days post-PE would appear to be a factor associated with SNL, while cholangitis within 3 months of PE would appear to be associated with LTx. Elevation of AST and γ-GT would also appear to be early indicators of risk for LTx during follow-up of JF patients after successful PE.     

Impact of technical modification of endoscopic papillectomy for ampullary neoplasm on the occurrence of complications

Aim: To evaluate the usefulness of a modified technique of endoscopic papillectomy (EP) for lessening the occurrence of complications. Methods: Indications for EP were adenoma or well‐differentiated adenocarcinoma confined to the papilla of Vater (T1) without tumor spread into the bile/pancreatic duct. Sixteen patients underwent the modified technique, which consists of resection with the Endocut^® mode, followed by biliary/pancreatic sphincterotomy and stenting (Group A). Twelve patients who had undergone EP, using a cutting current, followed by pancreatic duct stenting were included as control (Group B). The frequency of complications and clinical outcomes were retrospectively compared between the two groups. Results: Sixteen patients had adenoma, and 12 had adenocarcinoma. Early complications occurred in 36% of all patients (hemorrhage, 7; cholangitis, 3; perforation, 2; cholecystitis, 1). The frequency of early complications in Group A was significantly lower than that in Group B (6% vs 75%, odds ratio [OR] 0.022, 95% confidence interval [CI], 0.0020–0.25). Late complications occurred in 18% of the patients (bile duct stone, 3; hemorrhage, 1; pancreatitis, 1). There was no significant difference in the late complication rate between Group A and Group B (19% vs 17%). Local recurrences were found in 14% of the patients, without a significant difference between Group A and Group B (19% vs 8%) during a mean follow‐up period. All recurrent tumors were successfully treated with argon plasma coagulation. Conclusions: The modified technique of EP for ampullary neoplasm contributed to lessening the occurrence of early complications. However, further refinement of this technique is necessary for improving the clinical outcome.     

Endoscopic treatment for biliary stricture secondary to chronic pancreatitis

The causes of benign biliary stricture include chronic pancreatitis, primary/immunoglobulin G4-related sclerosing cholangitis and complications of surgical procedures. Biliary stricture due to fibrosis as a result of inflammation is sometimes encountered in patients with chronic pancreatitis. Frey's procedure, which can provide pancreatic duct drainage with decompression of biliary stricture, can be an initial treatment for chronic pancreatitis with pancreatic and bile duct strictures with upstream dilation. When patients are high-risk surgical candidates or hesitate to undergo surgery, endoscopic treatment appears to be a potential second-line therapy. Placement of multiple plastic stents is currently considered to be the best choice as endoscopic treatment for biliary stricture due to chronic pancreatitis. Temporary placement with a fully covered metal stent has become an attractive option due to the lesser number of endoscopic retrograde cholangiopancreatography (ERCP) sessions and its large diameter. Further clinical trials comparing multiple placement of plastic stents with placement of a covered metal stent for biliary stricture secondary to chronic pancreatitis are awaited.