Platelet count, spleen length, and platelet count-to-spleen length ratio for the diagnosis of oesophageal varices in people with chronic liver disease or portal vein thrombosis

Background: Current guidelines recommend screening of people with oesophageal varices via oesophago-gastro-duodenoscopy at the time of diagnosis of hepatic cirrhosis. This requires that people repeatedly undergo unpleasant invasive procedures with their attendant risks, although half of these people have no identifiable oesophageal varices 10 years after the initial diagnosis of cirrhosis. Platelet count, spleen length, and platelet count-to-spleen length ratio are non-invasive tests proposed as triage tests for the diagnosis of oesophageal varices. Objectives: Primary objectives To determine the diagnostic accuracy of platelet count, spleen length, and platelet count-to-spleen length ratio for the diagnosis of oesophageal varices of any size in paediatric or adult patients with chronic liver disease or portal vein thrombosis, irrespective of aetiology. To investigate the accuracy of these non-invasive tests as triage or replacement of oesophago-gastro-duodenoscopy. Secondary objectives To compare the diagnostic accuracy of these same tests for the diagnosis of high-risk oesophageal varices in paediatric or adult patients with chronic liver disease or portal vein thrombosis, irrespective of aetiology. We aimed to perform pair-wise comparisons between the three index tests, while considering predefined cut-off values. We investigated sources of heterogeneity. Search methods: The Cochrane Hepato-Biliary Group Controlled Trials Register, the Cochrane Hepato-Biliary Group Diagnostic Test Accuracy Studies Register, the Cochrane Library, MEDLINE (OvidSP), Embase (OvidSP), and Science Citation Index - Expanded (Web of Science) (14 June 2016). We applied no language or document-type restrictions. Selection criteria: Studies evaluating the diagnostic accuracy of platelet count, spleen length, and platelet count-to-spleen length ratio for the diagnosis of oesophageal varices via oesophago-gastro-duodenoscopy as the reference standard in children or adults of any age with chronic liver disease or portal vein thrombosis, who did not have variceal bleeding. Data collection and analysis: Standard Cochrane methods as outlined in the Cochrane Handbook for Diagnostic Test of Accuracy Reviews. Main results: We included 71 studies, 67 of which enrolled only adults and four only children. All included studies were cross-sectional and were undertaken at a tertiary care centre. Eight studies reported study results in abstracts or letters. We considered all but one of the included studies to be at high risk of bias. We had major concerns about defining the cut-off value for the three index tests; most included studies derived the best cut-off values a posteriori, thus overestimating accuracy; 16 studies were designed to validate the 909 (n/mm3)/mm cut-off value for platelet count-to-spleen length ratio. Enrolment of participants was not consecutive in six studies and was unclear in 31 studies. Thirty-four studies assessed enrolment consecutively. Eleven studies excluded some included participants from the analyses, and in only one study, the time interval between index tests and the reference standard was longer than three months. Diagnosis of varices of any size. Platelet count showed sensitivity of 0.71 (95% confidence interval (CI) 0.63 to 0.77) and specificity of 0.80 (95% CI 0.69 to 0.88) (cut-off value of around 150,000/mm3 from 140,000 to 150,000/mm3; 10 studies, 2054 participants). When examining potential sources of heterogeneity, we found that of all predefined factors, only aetiology had a role: studies including participants with chronic hepatitis C reported different results when compared with studies including participants with mixed aetiologies (P = 0.036). Spleen length showed sensitivity of 0.85 (95% CI 0.75 to 0.91) and specificity of 0.54 (95% CI 0.46 to 0.62) (cut-off values of around 110 mm, from 110 to 112.5 mm; 13 studies, 1489 participants). Summary estimates for detection of varices of any size showed sensitivity of 0.93 (95% CI 0.83 to 0.97) and specificity of 0.84 (95% CI 0.75 0.91) in 17 studies, and 2637 participants had a cut-off value for platelet count-to-spleen length ratio of 909 (n/mm3)/mm. We found no effect of predefined sources of heterogeneity. An overall indirect comparison of the HSROCs of the three index tests showed that platelet count-to-spleen length ratio was the most accurate index test when compared with platelet count (P 909 (n/mm3)/mm, the presence of oesophageal varices of any size can be excluded and only 7% of adults with varices of any size would be missed, allowing investigators to spare the number of oesophago-gastro-duodenoscopy examinations. This test is not accurate enough for identification of oesophageal varices at high risk of bleeding that require primary prophylaxis. Future studies should assess the diagnostic accuracy of this test in specific subgroups of patients, as well as its ability to predict variceal bleeding. New non-invasive tests should be examined

Analysis of Two-Body Decays of Charmed Baryons Using the Quark-Diagram Scheme

We give a general formulation of the quark-diagram scheme for the nonleptonic weak decays of baryons. We apply it to all the decays of the antitriplet and sextet charmed baryons and express their decay amplitudes in terms of the quark-diagram amplitudes. We have also given parametrizations for the effects of final-state interactions. For SU(3) violation effects, we only parametrize those in the horizontal $W$-loop quark diagrams whose contributions are solely due to SU(3)-violation effects. In the absence of all these effects, there are many relations among various decay modes. Some of the relations are valid even in the presence of final-state interactions when each decay amplitude in the relation contains only a single phase shift. All these relations provide useful frameworks to compare with future experiments and to find out the effects of final-state interactions and SU(3) symmetry violations.Comment: 28 pages, 20 Tables in landscape form, 4 figures. Main changes are: (i) some errors in the Tables and in the relations between the quark-diagram amplitudes of this paper and those of Ref.[10] are corrected, (ii) improvements are made in the presentation so that comparisons with previous works and what have been done to include SU(3) breaking and final-state interactions are more clearly stated; to appear in the Physical Review

Modelling spectral and timing properties of accreting black holes: the hybrid hot flow paradigm

The general picture that emerged by the end of 1990s from a large set of optical and X-ray, spectral and timing data was that the X-rays are produced in the innermost hot part of the accretion flow, while the optical/infrared (OIR) emission is mainly produced by the irradiated outer thin accretion disc. Recent multiwavelength observations of Galactic black hole transients show that the situation is not so simple. Fast variability in the OIR band, OIR excesses above the thermal emission and a complicated interplay between the X-ray and the OIR light curves imply that the OIR emitting region is much more compact. One of the popular hypotheses is that the jet contributes to the OIR emission and even is responsible for the bulk of the X-rays. However, this scenario is largely ad hoc and is in contradiction with many previously established facts. Alternatively, the hot accretion flow, known to be consistent with the X-ray spectral and timing data, is also a viable candidate to produce the OIR radiation. The hot-flow scenario naturally explains the power-law like OIR spectra, fast OIR variability and its complex relation to the X-rays if the hot flow contains non-thermal electrons (even in energetically negligible quantities), which are required by the presence of the MeV tail in Cyg X-1. The presence of non-thermal electrons also lowers the equilibrium electron temperature in the hot flow model to <100 keV, making it more consistent with observations. Here we argue that any viable model should simultaneously explain a large set of spectral and timing data and show that the hybrid (thermal/non-thermal) hot flow model satisfies most of the constraints.Comment: 26 pages, 13 figures. To be published in the Space Science Reviews and as hard cover in the Space Sciences Series of ISSI - The Physics of Accretion on to Black Holes (Springer Publisher

Is upper gastrointestinal radiography a cost-effective alternative to a Helicobacter pylori “Test and Treat” strategy for patients with suspected peptic ulcer disease?

Current clinical consensus supports an initial Helicobacter pylori (HP) “test and treat” approach when compared to immediate endoscopy for patients with suspected peptic ulcer disease. Alternative diagnostic approaches that incorporate upper GI radiography (UGI) have not been previously evaluated. We sought to determine the cost effectiveness of UGI compared to a HP test and treat strategy, incorporating recent data addressing the reduced prevalence of HP, lower cost of diagnostic interventions, and reduced attribution of PUD to HP. METHODS : Using decision analysis, three diagnostic and treatment strategies were evaluated: 1) Test and Treat —initial HP serology, treat patients who test positive with HP eradication and antiulcer therapy; 2) Initial UGI series —treat all patients with documented ulcer disease with HP eradication and antiulcer therapy; and 3) Initial UGI series, HP serology if ulcer present — treat ulcer and HP based on diagnostic test results. RESULTS : The estimated cost per ulcer cured for each strategy were as follows: test and treat, $3,025; initial UGI,$3,690; and UGI with serology, $3,790. The estimated cost per patient treatment were: test and treat,$498; initial UGI, $610; and UGI with serology,$620. When UGI reimbursement was decreased to less than $50, the UGI strategies yielded a lower cost per patient treated than the test and treat strategy. CONCLUSION : At the current level of reimbursement, UGI should not be considered a cost-effective alternative to the HP test and treat strategy for the initial evaluation of patients with suspected peptic ulcer disease.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/73722/1/j.1572-0241.2000.01837.x.pd

Search for lepton-flavor violation at HERA

A search for lepton-flavor-violating interactions $e p \to \mu X$ and $e p\to \tau X$ has been performed with the ZEUS detector using the entire HERA I data sample, corresponding to an integrated luminosity of 130 pb^{-1}. The data were taken at center-of-mass energies, $\sqrt{s}$, of 300 and 318 GeV. No evidence of lepton-flavor violation was found, and constraints were derived on leptoquarks (LQs) that could mediate such interactions. For LQ masses below $\sqrt{s}$, limits were set on $\lambda_{eq_1} \sqrt{\beta_{\ell q}}$, where $\lambda_{eq_1}$ is the coupling of the LQ to an electron and a first-generation quark $q_1$, and $\beta_{\ell q}$ is the branching ratio of the LQ to the final-state lepton $\ell$ ($\mu$ or $\tau$) and a quark $q$. For LQ masses much larger than $\sqrt{s}$, limits were set on the four-fermion interaction term $\lambda_{e q_\alpha} \lambda_{\ell q_\beta} / M_{\mathrm{LQ}}^2$ for LQs that couple to an electron and a quark $q_\alpha$ and to a lepton $\ell$ and a quark $q_\beta$, where $\alpha$ and $\beta$ are quark generation indices. Some of the limits are also applicable to lepton-flavor-violating processes mediated by squarks in $R$-Parity-violating supersymmetric models. In some cases, especially when a higher-generation quark is involved and for the process $e p\to \tau X$, the ZEUS limits are the most stringent to date.Comment: 37 pages, 10 figures, Accepted by EPJC. References and 1 figure (Fig. 6) adde

Measurement of (anti)deuteron and (anti)proton production in DIS at HERA

The first observation of (anti)deuterons in deep inelastic scattering at HERA has been made with the ZEUS detector at a centre-of-mass energy of 300--318 GeV using an integrated luminosity of 120 pb-1. The measurement was performed in the central rapidity region for transverse momentum per unit of mass in the range 0.3<p_T/M<0.7. The particle rates have been extracted and interpreted in terms of the coalescence model. The (anti)deuteron production yield is smaller than the (anti)proton yield by approximately three orders of magnitude, consistent with the world measurements.Comment: 26 pages, 9 figures, 5 tables, submitted to Nucl. Phys.