Search for Scalar Charm Quark Pair Production in pp Collisions at sqrt[s]=8 TeV with the ATLAS Detector

The results of a dedicated search for pair production of scalar partners of charm quarks are reported. The search is based on an integrated luminosity of 20.3  fb^{-1} of pp collisions at sqrt[s]=8  TeV recorded with the ATLAS detector at the LHC. The search is performed using events with large missing transverse momentum and at least two jets, where the two leading jets are each tagged as originating from c quarks. Events containing isolated electrons or muons are vetoed. In an R-parity-conserving minimal supersymmetric scenario in which a single scalar-charm state is kinematically accessible, and where it decays exclusively into a charm quark and a neutralino, 95% confidence-level upper limits are obtained in the scalar-charm-neutralino mass plane such that, for neutralino masses below 200 GeV, scalar-charm masses up to 490 GeV are excluded.

Measurement of spin correlation in top-antitop quark events and search for top squark pair production in pp collisions at √s=8 TeV using the ATLAS detector

A measurement of spin correlation in tt[over ¯] production is presented using data collected with the ATLAS detector at the Large Hadron Collider in proton-proton collisions at a center-of-mass energy of 8 TeV, corresponding to an integrated luminosity of 20.3  fb^{-1}. The correlation between the top and antitop quark spins is extracted from dilepton tt[over ¯] events by using the difference in the azimuthal angle between the two charged leptons in the laboratory frame. In the helicity basis the measured degree of correlation corresponds to A_{helicity}=0.38±0.04, in agreement with the standard model prediction. A search is performed for pair production of top squarks with masses close to the top quark mass decaying to predominantly right-handed top quarks and a light neutralino, the lightest supersymmetric particle. Top squarks with masses between the top quark mass and 191 GeV are excluded at the 95% confidence level.

Search for Higgs and Z Boson Decays to J/ψγ and ϒ(nS)γ with the ATLAS Detector

A search for the decays of the Higgs and Z bosons to J/ψγ and ϒ(nS)γ (n=1,2,3) is performed with pp collision data samples corresponding to integrated luminosities of up to 20.3  fb^{-1} collected at sqrt[s]=8  TeV with the ATLAS detector at the CERN Large Hadron Collider. No significant excess of events is observed above expected backgrounds and 95% C.L. upper limits are placed on the branching fractions. In the J/ψγ final state the limits are 1.5×10^{-3} and 2.6×10^{-6} for the Higgs and Z boson decays, respectively, while in the ϒ(1S,2S,3S)γ final states the limits are (1.3,1.9,1.3)×10^{-3} and (3.4,6.5,5.4)×10^{-6}, respectively.

Mutations in TJP2, encoding zona occludens 2, and liver disease

Progressive familial intrahepatic cholestasis is a clinical description of a phenotype, which we now realize has several different genetic aetiologies. The identification of the underlying genetic defects has helped to elucidate important aspects of liver physiology. The latest addition to this family of diseases is tight junction protein 2 (TJP2) deficiency. This protein is also known as zona occludens 2 (ZO-2). The patients, so far presented, all have homozygous, protein-truncating mutations. A complete absence of this protein was demonstrated. These children presented with severe liver disease, some manifesting extrahepatic features. By contrast, embryonic-lethality was seen in ZO-2 knockout mice. This discovery highlights important differences, not just between species, but also between different epithelia in humans. This commentary discusses the recently presented findings, and some of the issues that arise.

The current role of staging laparoscopy in oesophagogastric cancer

INTRODUCTION

Oesophagogastric cancers are known to spread rapidly to locoregional lymph nodes and by transcoelomic spread to the peritoneal cavity. Staging laparoscopy combined with peritoneal cytology can detect advanced disease that may not be apparent on other staging investigations. The aim of this study was to determine the current value of staging laparoscopy and peritoneal cytology in light of the ubiquitous use of computed tomography in all oesophagogastric cancers and the addition of positron emission tomography in oesophageal cancer.

METHODS

All patients undergoing staging laparoscopy for distal oesophageal or gastric cancer between March 2007 and August 2013 were identified from a prospectively maintained database. Demographic details, preoperative staging, staging laparoscopy findings, cytology and histopathology results were analysed.

RESULTS

A total of 317 patients were identified: 159 (50.1%) had gastric adenocarcinoma, 136 (43.0%) oesophageal adenocarcinoma and 22 (6.9%) oesophageal squamous carcinoma. Staging laparoscopy revealed macroscopic metastases in 36 patients (22.6%) with gastric adenocarcinoma and 16 patients (11.8%) with oesophageal adenocarcinoma. Positive peritoneal cytology in the absence of macroscopic peritoneal metastases was identified in a further five patients with gastric adenocarcinoma and six patients with oesophageal adenocarcinoma. There was no significant difference in survival between patients with macroscopic peritoneal disease and those with positive peritoneal cytology (p=0.219).

CONCLUSIONS

Staging laparoscopy and peritoneal cytology should be performed routinely in the staging of distal oesophageal and gastric cancers where other investigations indicate resectability. Currently, in our opinion, patients with positive peritoneal cytology should not be treated with curative intent.

Measurements of the Nuclear Modification Factor for Jets in Pb+Pb Collisions at √(s)NN]=2.76 TeV with the ATLAS detector

Measurements of inclusive jet production are performed in pp and Pb+Pb collisions at √(s)NN=2.76  TeV with the ATLAS detector at the LHC, corresponding to integrated luminosities of 4.0 and 0.14  nb(-1), respectively. The jets are identified with the anti-k(t) algorithm with R=0.4, and the spectra are measured over the kinematic range of jet transverse momentum 32<p(T)<500  GeV and absolute rapidity |y|<2.1 and as a function of collision centrality. The nuclear modification factor R(AA) is evaluated, and jets are found to be suppressed by approximately a factor of 2 in central collisions compared to pp collisions. The R(AA) shows a slight increase with p(T) and no significant variation with rapidity.

Search for scalar diphoton resonances in the mass range 65-600 GeV with the ATLAS detector in pp collision data at √s=8 TeV

A search for scalar particles decaying via narrow resonances into two photons in the mass range 65-600 GeV is performed using 20.3  fb(-1) of √s 8 TeV pp collision data collected with the ATLAS detector at the Large Hadron Collider. The recently discovered Higgs boson is treated as a background. No significant evidence for an additional signal is observed. The results are presented as limits at the 95% confidence level on the production cross section of a scalar boson times branching ratio into two photons, in a fiducial volume where the reconstruction efficiency is approximately independent of the event topology. The upper limits set extend over a considerably wider mass range than previous searches.

Massive gene amplification drives paediatric hepatocellular carcinoma caused by bile salt export pump deficiency

Hepatocellular carcinoma (HCC) is almost invariably associated with an underlying inflammatory state, whose direct contribution to the acquisition of critical genomic changes is unclear. Here we map acquired genomic alterations in human and mouse HCCs induced by defects in hepatocyte biliary transporters, which expose hepatocytes to bile salts and cause chronic inflammation that develops into cancer. In both human and mouse cancer genomes, we find few somatic point mutations with no impairment of cancer genes, but massive gene amplification and rearrangements. This genomic landscape differs from that of virus- and alcohol-associated liver cancer. Copy-number gains preferentially occur at late stages of cancer development and frequently target the MAPK signalling pathway, and in particular direct regulators of JNK. The pharmacological inhibition of JNK retards cancer progression in the mouse. Our study demonstrates that intrahepatic cholestasis leading to hepatocyte exposure to bile acids and inflammation promotes cancer through genomic modifications that can be distinguished from those determined by other aetiological factors.

Deprivation and ethnicity impact on diabetes control and use of treatment regimen

AIMS

Deprivation and/or ethnicity impact on care delivery. We have assessed how these factors influence diabetes care in a paediatric clinic.

METHODS

We related access to care [type of insulin treatment regimen-twice daily, multiple daily injections and insulin pump therapy (continuous subcutaneous insulin infusion)], measures of care process (HbA(1c)) and an approximate measure of satisfaction with the service (clinic attendance rate) in 325 (170 male) children and young people with Type 1 diabetes (mean age 10.6 years, mean duration of diabetes of 4.5 years), with indices of deprivation and ethnicity.

RESULTS

Of the 325 children and young people, 2.7% received twice-daily insulin, 48.4% multiple daily injections and 48.9% continuous subcutaneous insulin infusion. Median clinic HbA(1c) was 62 mmol/mol (7.8%) and those receiving the insulin pump therapy had the lowest HbA(1c). Four ethnic groups were represented; White British 81.6%, Asian non-Indian 6.5%, African 8.1% and Asian Indian 3.8%. Mean deprivation score was 21.06. White British and Asian Indian groups were more likely to receive insulin pump therapy (χ(2) = 50.3; P < 0.001). Attendance rates were 94.1% and did not differ across ethnic groups. Deprivation was related to ethnicity and HbA(1c) (R(2) = 0.02; P = 0.02). There was no relationship between clinic attendance and deprivation. Insulin regimen and ethnicity were associated with HbA(1c) (R(2) = 0.096; P < 0.001). Similar findings were obtained when analysis was confined to the White British population.

CONCLUSIONS

These data suggest that deprivation and ethnicity influence diabetes control and how intensive insulin therapy is utilized. A better consideration of the needs of different ethnic groups is required to ensure equitable care delivery in paediatric diabetes.

Frequency stability of a dual-mode whispering gallery mode optical reference cavity

We report an investigation of laser frequency stabilization using a whispering gallery mode resonator that is temperature stabilized by a dual-mode technique. This dual-mode technique has yielded mode volume temperature instabilities at the nK level, suggesting that high frequency stability may also be reached. Here, we experimentally and theoretically investigate the dynamics of such a system and the important factors affecting the achievable frequency stability. We calculate that the dual-mode technique can reduce the effective fractional temperature coefficient of the reference system to 3.6×10⁻⁸ K⁻¹ within the temperature feedback bandwidth. We demonstrate a 1560 nm laser stabilized to 1.3×10⁻¹² at 1 s and 1.1×10⁻¹⁰ at 1000 s, corresponding to a long-term drift of 21 kHz/hr.

ATP8B1 gene expression is driven by a housekeeping-like promoter independent of bile acids and farnesoid X receptor

Background

Mutations in ATP8B1 gene were identified as a cause of low γ-glutamyltranspeptidase cholestasis with variable phenotype, ranging from Progressive Familial Intrahepatic Cholestasis to Benign Recurrent Intrahepatic Cholestasis. However, only the coding region of ATP8B1 has been described. The aim of this research was to explore the regulatory regions, promoter and 5′untranslated region, of the ATP8B1 gene.

Methodology/Principal Findings

5′Rapid Amplification of cDNA Ends using human liver and intestinal tissue was performed to identify the presence of 5′ untranslated exons. Expression levels of ATP8B1 transcripts were determined by quantitative reverse-transcription PCR and compared with the non-variable part of ATP8B1. Three putative promoters were examined in vitro using a reporter gene assay and the main promoter was stimulated with chenodeoxycholic acid. Four novel untranslated exons located up to 71 kb upstream of the previously published exon 1 and twelve different splicing variants were found both in the liver and the intestine. Multiple transcription start sites were identified within exon −3 and the proximal promoter upstream of this transcription start site cluster was proven to be an essential regulatory element responsible for 70% of total ATP8B1 transcriptional activity. In vitro analysis demonstrated that the main promoter drives constitutive ATP8B1 gene expression independent of bile acids.

Conclusions/Significance

The structure of the ATP8B1 gene is complex and the previously published transcription start site is not significant. The basal expression of ATP8B1 is driven by a housekeeping-like promoter located 71 kb upstream of the first protein coding exon.

Temperature measurement and stabilization in a birefringent whispering gallery mode resonator

Temperature measurement with nano-Kelvin resolution is demonstrated at room temperature, based on the thermal dependence of an optical crystal anisotropy in a high quality whispering gallery mode resonator. As the resonator's TE and TM modes frequencies have different temperature coefficients, their differential shift provides a sensitive measurement of the temperature variation, which is used for active stabilization of the temperature.

Medical futility: a commonly used and potentially abused idea in medical ethics

Hospital doctors frequently invoke the idea of medical futility in making decisions regarding end-of-life care. This concept of futility will be reviewed and the differing definitions and how it relates to other important principles in biomedical ethics discussed.

Differences in presentation and progression between severe FIC1 and BSEP deficiencies

BACKGROUND & AIMS

Progressive familial intrahepatic cholestasis (PFIC) with normal serum levels of gamma-glutamyltranspeptidase can result from mutations in ATP8B1 (encoding familial intrahepatic cholestasis 1 [FIC1]) or ABCB11 (encoding bile salt export pump [BSEP]). We evaluated clinical and laboratory features of disease in patients diagnosed with PFIC, who carried mutations in ATP8B1 (FIC1 deficiency) or ABCB11 (BSEP deficiency). Our goal was to identify features that distinguish presentation and course of these two disorders, thus facilitating diagnosis and elucidating the differing consequences of ATP8B1 and ABCB11 mutations.

METHODS

A retrospective multi-center study was conducted, using questionnaires and chart review. Available clinical and biochemical data from 145 PFIC patients with mutations in either ATP8B1 (61 "FIC1 patients") or ABCB11 (84 "BSEP patients") were evaluated.

RESULTS

At presentation, serum aminotransferase and bile salt levels were higher in BSEP patients; serum alkaline phosphatase values were higher, and serum albumin values were lower, in FIC1 patients. Elevated white blood cell counts, and giant or multinucleate cells at liver biopsy, were more common in BSEP patients. BSEP patients more often had gallstones and portal hypertension. Diarrhea, pancreatic disease, rickets, pneumonia, abnormal sweat tests, hearing impairment, and poor growth were more common in FIC1 patients. Among BSEP patients, the course of disease was less rapidly progressive in patients bearing the D482G mutation.

CONCLUSIONS

Severe forms of FIC1 and BSEP deficiency differed. BSEP patients manifested more severe hepatobiliary disease, while FIC1 patients showed greater evidence of extrahepatic disease.

Contribution of variant alleles of ABCB11 to susceptibility to intrahepatic cholestasis of pregnancy

BACKGROUND

Intrahepatic cholestasis of pregnancy (ICP) has a complex aetiology with a significant genetic component. ABCB11 encodes the bile salt export pump (BSEP); mutations cause a spectrum of cholestatic disease, and are implicated in the aetiology of ICP.

METHODS

ABCB11 variation in ICP was investigated by screening for five mutant alleles (E297G, D482G, N591S, D676Y and G855R) and the V444A polymorphism (c.1331T>C, rs2287622) in two ICP cohorts (n = 333 UK, n = 158 continental Europe), and controls (n = 261) for V444A. PCR primers were used to amplify and sequence patient and control DNA. The molecular basis for the observed phenotypes was investigated in silico by analysing the equivalent residues in the structure of the homologous bacterial transporter Sav1866.

RESULTS

E297G was observed four times and D482G once. N591S was present in two patients; D676Y and G855R were not observed. The V444A polymorphism was associated with ICP (allelic analysis for C vs T: OR 1.7 (95% CI 1.4 to 2.1, p<0.001)). In addition, CC homozygotes were more likely to have ICP than TT homozygotes: OR 2.8 (95% CI 1.7 to 4.4 p<0.0001). Structural analyses suggest that E297G and D482G destabilize the protein fold of BSEP. The molecular basis of V444A and N591S was not apparent from the Sav1866 structure.

CONCLUSIONS

Heterozygosity for the common ABCB11 mutations accounts for 1% of European ICP cases; these two mutants probably reduce the folding efficiency of BSEP. N591S is a recurrent mutation; however, the mechanism may be independent of protein stability or function. The V444A polymorphism is a significant risk factor for ICP in this population.

Validation of a decision support tool for the evaluation of cardiac arrest victims

BACKGROUND

There is currently no well-accepted model for early and accurate prediction of neurologic and vital outcomes after cardiac arrest. Recent studies indicate that individuals with acute myocardial ischemia as the etiology for the arrest may benefit from early revascularization.

HYPOTHESIS

This study was undertaken to examine whether the cardiac arrest score is valid for predicting outcomes upon arrival at the emergency department.

METHODS

We previously developed a cardiac arrest score based on time to return of spontaneous circulation, initial systolic blood pressure, and level of neurologic alertness in 127 patients (derivation set). This score was prospectively applied to 62 patients with similar clinical profiles (validation set). Utility of the score was evaluated by the area under the receiver operator characteristic curves (C) for both sets. Consistency was measured by using the alpha statistic applied to the cumulative survival at each ascending level of the score.

RESULTS

The derivation and validation sets were similar with respect to baseline characteristics and proportions at each level of score. The survival to discharge was 41.7 and 53.2% for the two sets, respectively. The value of C was 0.89 +/- 0.03 and 0.93 +/- 0.03 for neurologic recovery and 0.81 +/- 0.04 and 0.92 +/- 0.04 for survival to discharge in the two sets, respectively. The level of agreement between the sets across the levels of the score was 0.98 and 0.99 (both p < 0.0001) for the two outcomes.

CONCLUSIONS

The cardiac arrest score is a valid decision support tool in the evaluation of cardiac arrest victims. Patients with the most favorable scores may be considered for early angiography and revascularization if myocardial ischemia is the etiology of the arrest.

Missense mutations and single nucleotide polymorphisms in ABCB11 impair bile salt export pump processing and function or disrupt pre-messenger RNA splicing

The gene encoding the human bile salt export pump (BSEP), ABCB11, is mutated in several forms of intrahepatic cholestasis. Here we classified the majority (63) of known ABCB11 missense mutations and 21 single-nucleotide polymorphisms (SNPs) to determine whether they caused abnormal ABCB11 pre-messenger RNA splicing, abnormal processing of BSEP protein, or alterations in BSEP protein function. Using an in vitro minigene system to analyze splicing events, we found reduced wild-type splicing for 20 mutations/SNPs, with normal mRNA levels reduced to 5% or less in eight cases. The common ABCB11 missense mutation encoding D482G enhanced aberrant splicing, whereas the common SNP A1028A promoted exon skipping. Addition of exogenous splicing factors modulated several splicing defects. Of the mutants expressed in vitro in CHO-K1 cells, most appeared to be retained in the endoplasmic reticulum and degraded. A minority had BSEP levels similar to wild-type. The SNP variant A444 had reduced levels of protein compared with V444. Treatment with glycerol and incubation at reduced temperature overcame processing defects for several mutants, including E297G. Taurocholate transport by two assessed mutants, N490D and A570T, was reduced compared with wild-type.

CONCLUSION

This work is a comprehensive analysis of 80% of ABCB11 missense mutations and single-nucleotide polymorphisms at pre-mRNA splicing and protein processing/functional levels. We show that aberrant pre-mRNA splicing occurs in a considerable number of cases, leading to reduced levels of normal mRNA. Thus, primary defects at either the protein or the mRNA level (or both) contribute significantly to BSEP deficiency. These results will help to develop mutation-specific therapies for children and adults suffering from intrahepatic cholestasis due to BSEP deficiency.

Bile composition in Alagille Syndrome and PFIC patients having Partial External Biliary Diversion

BACKGROUND

Partial External Biliary Diversion (PEBD) is a surgical intervention to treat children with Progressive Familial Intrahepatic Cholestasis (PFIC) and Alagille syndrome (AGS). PEBD can reduce disease progression, and examining the alterations in biliary lipid composition may be a prognostic factor for outcome.

METHODS

Biliary lipid composition and the clinical course of AGS and PFIC patients were examined before and after PEBD.

RESULTS

Pre-PEBD bile from AGS patients had greater chenodeoxycholic/cholic acid (CDCA/CA), bile salt, cholesterol and phospholipid concentrations than PFIC patients. AGS patients, and PFIC patients with familial intrahepatic cholestasis 1 (FIC1) genotype, responded better to PEBD than PFIC patients with bile salt export protein (BSEP) genotype. After successful PEBD, AGS patients have higher biliary lipid concentrations than PFIC patients and PEBD also increases biliary phospholipid concentrations in FIC1 patients.

CONCLUSION

Both AGS and FIC1 patients can benefit from PEBD, and preserved biliary phospholipid concentrations may be associated with better outcomes post-PEBD.

Congenital bile duct anomalies (biliary atresia) and chromosome 22 aneuploidy

Biliary atresia is a disease of unknown etiology but not usually thought to have a significant genetic predisposition. We report 5 infants with various forms of chromosome 22 aneuploidy as follows: 2 infants who have classical cat-eye syndrome, 2 who have partial duplication of chromosome 22 (supernumerary der(22) syndrome), and 1 who is mosaic for trisomy 22. All of these infants had significant congenital bile duct anomalies (specifically biliary atresia, n = 4)-that was the most important component of their clinical presentation. We consider whether this has possible implications about the genetic contribution to the etiology of biliary atresia.

The function of the midtarsal joint: a review of the literature

The midtarsal joint (MTJt) consists of the combined articulations of the talonavicular and calcaneocuboid joints and represents the functional articulation between the rearfoot (talus and calcaneus) and the midfoot (navicular and cuboid). The movement of the transverse tarsal region has been described as a segment rotating around two distinct axes of the MTJt; the longitudinal and the oblique. Recent research has suggested that the two axes model of the MTJt is a theory of convenience to explain clinical observation, and that the MTJt moves in a more complex manner. It has been hypothesised that the MTJt has one triplanar axis of motion, so there remains the need to investigate the practical application of this understanding in terms of how this motion affects the MTJt in gait and the implications this may have on podiatric treatment.

Severe bile salt export pump deficiency: 82 different ABCB11 mutations in 109 families

BACKGROUND & AIMS

Patients with severe bile salt export pump (BSEP) deficiency present as infants with progressive cholestatic liver disease. We characterized mutations of ABCB11 (encoding BSEP) in such patients and correlated genotypes with residual protein detection and risk of malignancy.

METHODS

Patients with intrahepatic cholestasis suggestive of BSEP deficiency were investigated by single-strand conformation polymorphism analysis and sequencing of ABCB11. Genotypes sorted by likely phenotypic severity were correlated with data on BSEP immunohistochemistry and clinical outcome.

RESULTS

Eighty-two different mutations (52 novel) were identified in 109 families (9 nonsense mutations, 10 small insertions and deletions, 15 splice-site changes, 3 whole-gene deletions, 45 missense changes). In 7 families, only a single heterozygous mutation was identified despite complete sequence analysis. Thirty-two percent of mutations occurred in >1 family, with E297G and/or D482G present in 58% of European families (52/89). On immunohistochemical analysis (88 patients), 93% had abnormal or absent BSEP staining. Expression varied most for E297G and D482G, with some BSEP detected in 45% of patients (19/42) with these mutations. Hepatocellular carcinoma or cholangiocarcinoma developed in 15% of patients (19/128). Two protein-truncating mutations conferred particular risk; 38% (8/21) of such patients developed malignancy versus 10% (11/107) with potentially less severe genotypes (relative risk, 3.7 [confidence limits, 1.7-8.1; P = .003]).

CONCLUSIONS

With this study, >100 ABCB11 mutations are now identified. Immunohistochemically detectable BSEP is typically absent, or much reduced, in severe disease. BSEP deficiency confers risk of hepatobiliary malignancy. Close surveillance of BSEP-deficient patients retaining their native liver, particularly those carrying 2 null mutations, is essential.

Endoscopically assisted minimally invasive surgery for gallstones

BACKGROUND

We present a case report of Bouveret syndrome followed by a review of the recent literature regarding the management of this condition. Bouveret syndrome is a form of gastric outlet obstruction secondary to a gallstone which has eroded through the gallbladder into the duodenum. It is an uncommon variant of gallstone ileus. Endoscopic methods have been described to extract the stone from the duodenum.

METHODS

This is a case of an 85-year-old female patient who presented with a 1-week history of nausea, intermittent bilious vomiting and anorexia. Imaging confirmed the diagnosis of Bouveret syndrome caused by two large gallstones. Conventional endoscopic methods successfully extracted the impacted stones from the duodenum into the stomach but were unable to extract the stones from the stomach. A mini-transverse laparotomy and gastrotomy were performed to finally extract the stones.