Microscopic Formulation of Black Holes in String Theory

In this Report we review the microscopic formulation of the five dimensional black hole of type IIB string theory in terms of the D1-D5 brane system. The emphasis here is more on the brane dynamics than on supergravity solutions. We show how the low energy brane dynamics, combined with crucial inputs from AdS/CFT correspondence, leads to a derivation of black hole thermodynamics and the rate of Hawking radiation. Our approach requires a detailed exposition of the gauge theory and conformal field theory of the D1-D5 system. We also discuss some applications of the AdS/CFT correspondence in the context of black hole formation in three dimensions by thermal transition and by collision of point particles.Comment: (v2) To appear in Physics Reports; 168 pages, 4 figures. References and clarifications adde

Genome-wide association study of primary sclerosing cholangitis identifies new risk loci and quantifies the genetic relationship with inflammatory bowel disease.

Primary sclerosing cholangitis (PSC) is a rare progressive disorder leading to bile duct destruction; ∼75% of patients have comorbid inflammatory bowel disease (IBD). We undertook the largest genome-wide association study of PSC (4,796 cases and 19,955 population controls) and identified four new genome-wide significant loci. The most associated SNP at one locus affects splicing and expression of UBASH3A, with the protective allele (C) predicted to cause nonstop-mediated mRNA decay and lower expression of UBASH3A. Further analyses based on common variants suggested that the genome-wide genetic correlation (rG) between PSC and ulcerative colitis (UC) (rG = 0.29) was significantly greater than that between PSC and Crohn's disease (CD) (rG = 0.04) (P = 2.55 × 10-15). UC and CD were genetically more similar to each other (rG = 0.56) than either was to PSC (P < 1.0 × 10-15). Our study represents a substantial advance in understanding of the genetics of PSC

Epidemiology of primary sclerosing cholangitis and primary biliary cirrhosis: A systematic review

Objective: Studies on the epidemiology of primary sclerosing cholangitis (PSC) and primary biliary cirrhosis (PBC) show variable outcome. We aimed at systematically reviewing the incidence and prevalence rates, as well as geographical distribution and temporal trends of PSC and PBC. Data sources: A systematic search of literature was performed in Medline and EMBASE (search last conducted January 10th, 2011). Study selection: Population-based epidemiological studies reporting incidence and/or prevalence rates for PSC or PBC in a defined geographical area of at least 100,000 adult inhabitants were considered relevant. Data extraction: Study area, study period, number of patients, number of inhabitants, incidence per 100,000 inhabitants per year, prevalence per 100,000 inhabitants, method of case-finding, method of case-ascertainment, male/female ratio and in case of PSC, occurrence of inflammatory bowel diseases (IBD) were extracted from retrieved articles. Results: The literature search yielded 2286 abstracts of which 31 articles fulfilled all inclusion criteria. Studies varied in size from 10 to 770 patients in catchment areas from 100,312 to 19,230,000 inhabitants. The incidence and prevalence rates for PSC range from 0 to 1.3 per 100,000 inhabitants/year and 0-16.2 per 100,000 inhabitants, respectively. PBC incidence rates range from 0.33 to 5.8 per 100,000 inhabitants/year and prevalence rates range from 1.91 to 40.2 per 100,000 inhabitants; prevalence rates are increasing in time. Conclusions: Incidence and prevalence rates of both PSC and PBC vary widely and seem to be increasing. True population-based studies are scarce and therefore large population-based studies combining meticulous case-finding and case-ascertainment strategies are necessary. (C) 2012 European Association for the Study of the Liver. Published by Elsevier B.V. All rights reserve

Applicability and prognostic value of histologic scoring systems in primary sclerosing cholangitis

Primary sclerosing cholangitis (PSC) is a chronic cholestatic liver disease. At present, there is no appropriate histologic scoring system available for PSC, evaluating both degree of necroinflammatory activity (grade) and fibrosis (stage). The aim of this study was to assess if three scoring systems, commonly used in different liver diseases could be applied for grading and/or staging of PSC. Sixty-four PSC patients from a Dutch cohort, who underwent diagnostic liver biopsy, were included. Staging was scored using Ishak, Nakanuma, and Ludwig systems. Grading was scored using Ishak and Nakanuma systems. Three measures of outcome were defined; transplant-free survival, time to liver transplantation (LTx) and occurrence of cirrhosis related symptoms (CRS). Association of grade and stage with outcome was estimated using Kaplan-Meier log-rank test, and Cox regression analysis. Correlation with biochemistry was assessed by Spearman's rank test. There were strong associations between disease stage measured by Ishak, Nakanuma, and Ludwig staging systems with both outcome measuring transplant-free survival (Hazard ratio (HR) 2.56; 95% CI 1.11-5.89, HR 6.53; 95% CI 2.01-21.22, HR 1.94; 95% CI 1.00-3.79, respectively), and time to LTx (HR 4.18; 95%CI 1.51-11.56, HR 7.05; 95% CI 1.77-28.11, HR 3.13; 95%CI 1.42-6.87, respectively). Ishak and Nakanuma grading systems were not associated with CRS. Weak correlations between histopathology and liver biochemistry were shown. Applying the Nakanuma, Ishak, and Ludwig histopathological staging systems is feasible and clinically relevant given their association with transplant-free survival and time to LTx. This suggests that these staging systems could be likely candidates for surrogate endpoints and stratification purposes in clinical trials in PS

The mucosa-associated microbiota of PSC patients is characterized by low diversity and low abundance of uncultured Clostridiales II

Primary sclerosing cholangitis (PSC) is a cholestatic liver disease that is strongly associated with a particular phenotype of inflammatory bowel disease (IBD) with right-sided colonic involvement. In IBD, several studies demonstrated significant aberrancies in the intestinal microbiota in comparison with healthy controls. We aimed to explore the link between IBD and PSC by studying the intestinal mucosa-adherent microbiota in PSC and ulcerative colitis (UC) patients and noninflammatory controls. We included 12 PSC patients, 11 UC patients, and nine noninflammatory controls. The microbiota composition was determined in ileocecal biopsies from each patient by 16S rRNA-based analyses using the human intestinal tract chip. Profiling of the mucosa-adherent microbiota of PSC patients, UC patients, and noninflammatory controls revealed that these groups did not cluster separately based on microbiota composition. At the genus-like level, the relative abundance of uncultured Clostridiales II was significantly lower (almost 2-fold) in PSC (0.26 ± 0.10%) compared with UC (0.41 ± 0.29%) and controls (0.49 ± 0.25%) (p = 0.02). Diversity and richness in the microbiota composition differed across the groups and were significantly lower in PSC patients compared with noninflammatory controls (p = 0.04 and p = 0.02, respectively). No significant differences were found in evenness. Reduced amounts of uncultured Clostridiales II in PSC biopsies in comparison with UC and healthy controls can be considered a signature of a compromised gut, as we have recently observed that this group of as yet uncultured Firmicutes correlates significantly with healt

IgG4-Associated Cholangitis--A Mimic of PSC

IgG4-associated cholangitis (IAC) is an inflammatory disorder of the biliary tract representing a major manifestation of IgG4-related disease (IgG4-RD) often with elevation of serum IgG4 levels, infiltration of IgG4+ plasma cells in the affected tissue and good response to immunosuppressive treatment. Its first description may go back to 150 years ago. The clinical presentation of IAC is often misleading, mimicking other biliary diseases such as primary sclerosing cholangitis (PSC) or cholangiocarcinoma. The HISORt criteria--histopathological, imaging, and serological features (sIgG4), other organ manifestations of IgG4-RD and response to treatment--are the standard for the diagnosis of IAC. In this overview of a recent lecture, we summarize our original findings on IgG4-RD that (i) dominant IgG4+ B-cell clones identified by advanced next generation sequencing (NGS) are highly specific for IgG4-RD (meanwhile confirmed by others), are a highly accurate diagnostic marker to distinguish IgG4-RD from PSC and biliary/pancreatic malignancies and may be crucial in unravelling the pathophysiology of IgG4-RD; (ii) sIgG4/sIgG1 >0.24 have additional diagnostic value in comparison to sIgG4 in differentiating IAC from PSC; (iii) blood IgG4 mRNA is a highly accurate diagnostic marker comparable to NGS and may become an easily available and affordable diagnostic standard for distinguishing IgG4-RD from PSC and biliary/pancreatic malignancies; and (iv) 'blue collar work' with long-term exposure to solvents, paints, oil products or industrial gases may be a risk factor for development of IgG4-RD. These findings may contribute to the understanding of the pathophysiology and to the early diagnosis and adequate treatment of IgG4-R

Alkaline phosphatase at diagnosis of primary sclerosing cholangitis and one year later: Evaluation of prognostic value

Primary sclerosing cholangitis (PSC) is a slowly progressive liver disease. Reliable biomarkers to predict outcome are urgently needed to serve as surrogate endpoints and/or stratifiers in clinical trials. Reduction in serum alkaline phosphatase (ALP) has been proposed as prognostic surrogate marker in PSC. The aim of this study was to asses if ALP at diagnosis (T0), 1 year later (T1), and percentage change between both time points hold prognostic value, and to determine the optimal threshold. We retrospectively collected ALP levels at T0 and T1 for patients included in a large PSC cohort. The association of ALP at T0, T1, and percentage change with the combined endpoint (PSC-related death, liver transplantation) was analysed. Predictive value was determined using C-statistics. A total of 366 patients were included, of whom 66 (18%) reached an endpoint: 26 (7%) PSC-related death, 40 (11%) liver transplantation. At T0 and T1, 84% used ursodeoxycholic acid. A positive association was observed between level of ALP at T0 and T1 and the hazard of reaching an endpoint, up to values around 2.5 times upper limit of normal (xULN). A larger decrease in ALP between T0 and T1 decreased the event rate. A range of thresholds (0.5-3×ULN) with about similar C-statistics was found. In this cohort, the optimal threshold was 1.3×ULN at T1. ALP can be used to discriminate between PSC patients with a good and a poor prognosis. These findings indicate that ALP can serve as stratifier, and potentially as surrogate endpoint for clinical trials in PS