Hospital Authority audit of the outcome of endoscopic resection of superficial upper gastro-intestinal lesions in Hong Kong

published_or_final_versio

Moisture transport by Atlantic tropical cyclones onto the North American continent

Tropical Cyclones (TCs) are an important source of freshwater for the North American continent. Many studies have tried to estimate this contribution by identifying TC-induced precipitation events, but few have explicitly diagnosed the moisture fluxes across continental boundaries. We design a set of attribution schemes to isolate the column-integrated moisture fluxes that are directly associated with TCs and to quantify the flux onto the North American Continent due to TCs. Averaged over the 2004–2012 hurricane seasons and integrated over the western, southern and eastern coasts of North America, the seven schemes attribute 7 to 18 % (mean 14 %) of total net onshore flux to Atlantic TCs. A reduced contribution of 10 % (range 9 to 11 %) was found for the 1980–2003 period, though only two schemes could be applied to this earlier period. Over the whole 1980–2012 period, a further 8 % (range 6 to 9 % from two schemes) was attributed to East Pacific TCs, resulting in a total TC contribution of 19 % (range 17 to 22 %) to the ocean-to-land moisture transport onto the North American continent between May and November. Analysis of the attribution uncertainties suggests that incorporating details of individual TC size and shape adds limited value to a fixed radius approach and TC positional errors in the ERA-Interim reanalysis do not affect the results significantly, but biases in peak wind speeds and TC sizes may lead to underestimates of moisture transport. The interannual variability does not appear to be strongly related to the El Nino-Southern Oscillation phenomenon

Fiber guiding at the Dirac frequency beyond photonic bandgaps

Light trapping within waveguides is a key practice of modern optics, both scientifically and technologically. Photonic crystal fibers traditionally rely on total internal reflection (index-guiding fibers) or a photonic bandgap (photonic-bandgap fibers) to achieve field confinement. Here, we report the discovery of a new light trapping within fibers by the so-called Dirac point of photonic band structures. Our analysis reveals that the Dirac point can establish suppression of radiation losses and consequently a novel guided mode for propagation in photonic crystal fibers. What is known as the Dirac point is a conical singularity of a photonic band structure where wave motion obeys the famous Dirac equation. We find the unexpected phenomenon of wave localization at this point beyond photonic bandgaps. This guiding relies on the Dirac point rather than total internal reflection or photonic bandgaps, thus providing a sort of advancement in conceptual understanding over the traditional fiber guiding. The result presented here demonstrates the discovery of a new type of photonic crystal fibers, with unique characteristics that could lead to new applications in fiber sensors and lasers. The Dirac equation is a special symbol of relativistic quantum mechanics. Because of the similarity between band structures of a solid and a photonic crystal, the discovery of the Dirac-point-induced wave trapping in photonic crystals could provide novel insights into many relativistic quantum effects of the transport phenomena of photons, phonons, and electrons

Cervical epidural steroid injections in the management of cervical radiculitis: interlaminar versus transforaminal. A review

There has been recent concern regarding the safety of cervical epidural steroid injections. The decision to proceed with treatment requires balancing the risk and benefits. This article is an in depth review of the efficacy, complications, and technique of both interlaminar and transforaminal cervical epidural steroid injections in the management of cervical radiculitis

Survival and hepatitis status among Asian Americans with hepatocellular carcinoma treated without liver transplantation

<p>Abstract</p> <p>Background</p> <p>Chronic hepatitis B virus (HBV) and hepatitis C virus (HCV) are established causes of HCC. HCC patients are often diagnosed late and receive palliative therapies, however, the survival of Asian American patients with HCC treated without transplantation has not been well studied. We reviewed our institution's experience to determine predictors and rates of survival in Asian American HCC patients treated without transplantation.</p> <p>Methods</p> <p>We identified Asian American patients with HCC referred to M. D. Anderson Cancer Center. Patients were tested for HBV and HCV. Survival curves were generated by Kaplan-Meier method. Multivariate Cox proportional hazards regression was used to test the relationship between prognostic factors and survival.</p> <p>Results</p> <p>Of 82 Asian American HCC patients, most had advanced disease (65%) and received treatment (68%); however, only 11% had surgical resection. 94% had positive anti-HBc and 61% had positive HBsAg. 20% had positive anti-HCV. There were no significant changes in the rates of HBV and HCV over time. Male gender, high alpha-fetoprotein levels, and stage IV disease were associated with shorter survival Overall median survival was 9.2 months (95% CI 6.5–11.9), and the survival of HCV and HBV patients was not statistically different.</p> <p>Conclusion</p> <p>The survival rate of Asian American patients with advanced HCC, for whom transplantation was not available, was low. Timely hepatitis screening and interventions by primary care physicians may be the most logical solution to reduce the burden of hepatitis-associated HCC among Asian Americans.</p

Epstein-Barr Virus Associated Modulation of Wnt Pathway Is Not Dependent on Latent Membrane Protein-1

Previous studies have indicated that Epstein-Barr virus (EBV) can modulate the Wnt pathway in virus-infected cells and this effect is mediated by EBV-encoded oncogene latent membrane protein 1 (LMP1). Here we have reassessed the role of LMP1 in regulating the expression of various mediators of the canonical Wnt cascade. Contradicting the previous finding, we found that the levels of E-cadherin, β-catenin, Glycogen Synthase Kinase 3ß (GSK3β), axin and α-catenin were not affected by the expression of LMP1 sequences from normal B cells or nasopharyngeal carcinoma. Moreover, we also show that LMP1 expression had no detectable effect on the E-cadherin and β-catenin interaction and did not induce transcriptional activation of β-catenin. Taken together these studies demonstrate that EBV-mediated activation of Wnt pathway is not dependent on the expression of LMP1

Extremely metal-poor gas at a redshift of 7

In typical astrophysical environments, the abundance of heavy elements ranges from 0.001 to 2 times the solar value. Lower abundances have been seen in selected stars in the Milky Way’s halo and in two quasar absorption systems at redshift z = 3 (ref. 4). These are widely interpreted as relics from the early Universe, when all gas possessed a primordial chemistry. Before now there have been no direct abundance measurements from the first billion years after the Big Bang, when the earliest stars began synthesizing elements. Here we report observations of hydrogen and heavy-element absorption in a spectrum of a quasar at z =  7.04, when the Universe was just 772 million years old (5.6 per cent of its present age). We detect a large column of neutral hydrogen but no corresponding metals (defined as elements heavier than helium), limiting the chemical abundance to less than 1/10,000 times the solar level if the gas is in a gravitationally bound proto-galaxy, or to less than 1/1,000 times the solar value if it is diffuse and unbound. If the absorption is truly intergalactic, it would imply that the Universe was neither ionized by starlight nor chemically enriched in this neighbourhood at z ≈ 7. If it is gravitationally bound, the inferred abundance is too low to promote efficient cooling, and the system would be a viable site to form the predicted but as yet unobserved massive population III stars

Estrogen receptor-alpha (ER-alpha) and defects in uterine receptivity in women

Endometriosis is a disorder that affects 5% of the normal population but is present in up to 40% of women with pelvic pain and/or infertility. Recent evidence suggests that the endometrium of women with endometriosis exhibits progesterone insensitivity. One endometrial protein that fluctuates in response to progesterone is the estrogen receptor-alpha (ER alpha), being down-regulated at the time of peak progesterone secretion during the window of implantation. Here we demonstrate that the biomarker of uterine receptivity, beta 3 integrin subunit, is reduced or absent in some women with endometriosis and that such defects are accompanied by inappropriate over-expression of ER alpha during the mid-secretory phase. Using a well-differentiated endometrial cell line we showed that the beta 3 integrin protein is negatively regulated by estrogen and positively regulated by epidermal growth factor (EGF). By competing against estrogen with various selective estrogen receptor modulators (SERMs) and estrogen receptor agonists and antagonists, inhibition of expression of the beta 3 integrin by estrogen can be mitigated. In conclusion, we hypothesize that certain types of uterine receptivity defects may be caused by the loss of appropriate ER alpha down-regulation in the mid-secretory phase, leading to defects in uterine receptivity. Such changes might be effectively treated by timely administration of the appropriate anti-estrogens to artificially block ER alpha and restore normal patterns of gene expression. Such treatments will require further clinical studies

Correlates of HCV seropositivity among familial contacts of HCV positive patients

BACKGROUND: Determinants of intrafamilial HCV transmission are still being debated. The aim of this study is to investigate the correlates of HCV seropositivity among familial contacts of HCV positive patients in Italy. METHODS: A cross-sectional study was conducted with 175 HCV positive patients (index cases), recruited from Policlinico Gemelli in Rome as well as other hospitals in Central Italy between 1995 and 2000 (40% female, mean age 57 ± 15.2 years), and 259 familial contacts. Differences in proportions of qualitative variables were tested with non-parametric tests (χ(2), Yates correction, Fisher exact test), and a p value < 0.05 was considered significant. A multivariate analysis was conducted using logistic regression in order to verify which variables statistically have an influence on HCV positivity in contact individuals. RESULTS: Seropositivity for HCV was found in 8.9% of the contacts. From the univariate analysis, risk factors significantly associated to HCV positivity in the contacts were: intravenous drug addiction (p = 0.004) and intercourse with drug addicts (p = 0.005). The only variables associated significantly and independently to HCV seropositivity in patients' contacts were intercourse with drug addicts (OR = 19.28; 95% CI: 2.01 – 184.94), the retirement status from work (OR = 3.76; 95% CI: 1.17 – 11.98), the time of the relationship (OR = 1.06; 95% CI: 1.00 – 1.11) and tattoos (OR = 7.68; 95% CI: 1.00 – 60.20). CONCLUSION: The present study confirms that having intercourse with a drug addict is the most significant risk factor for intrafamilial HCV transmission. The association with retirement status from work could be related to both a long-term relationship with an index case and past exposure to common risk factors

Common Variants at 10 Genomic Loci Influence Hemoglobin A(1C) Levels via Glycemic and Nonglycemic Pathways

OBJECTIVE Glycated hemoglobin (HbA1c), used to monitor and diagnose diabetes, is influenced by average glycemia over a 2- to 3-month period. Genetic factors affecting expression, turnover, and abnormal glycation of hemoglobin could also be associated with increased levels of HbA1c. We aimed to identify such genetic factors and investigate the extent to which they influence diabetes classification based on HbA1c levels. RESEARCH DESIGN AND METHODS We studied associations with HbA1c in up to 46,368 nondiabetic adults of European descent from 23 genome-wide association studies (GWAS) and 8 cohorts with de novo genotyped single nucleotide polymorphisms (SNPs). We combined studies using inverse-variance meta-analysis and tested mediation by glycemia using conditional analyses. We estimated the global effect of HbA1c loci using a multilocus risk score, and used net reclassification to estimate genetic effects on diabetes screening. RESULTS Ten loci reached genome-wide significant association with HbA1c, including six new loci near FN3K (lead SNP/P value, rs1046896/P = 1.6 × 10−26), HFE (rs1800562/P = 2.6 × 10−20), TMPRSS6 (rs855791/P = 2.7 × 10−14), ANK1 (rs4737009/P = 6.1 × 10−12), SPTA1 (rs2779116/P = 2.8 × 10−9) and ATP11A/TUBGCP3 (rs7998202/P = 5.2 × 10−9), and four known HbA1c loci: HK1 (rs16926246/P = 3.1 × 10−54), MTNR1B (rs1387153/P = 4.0 × 10−11), GCK (rs1799884/P = 1.5 × 10−20) and G6PC2/ABCB11 (rs552976/P = 8.2 × 10−18). We show that associations with HbA1c are partly a function of hyperglycemia associated with 3 of the 10 loci (GCK, G6PC2 and MTNR1B). The seven nonglycemic loci accounted for a 0.19 (% HbA1c) difference between the extreme 10% tails of the risk score, and would reclassify ∼2% of a general white population screened for diabetes with HbA1c. CONCLUSIONS GWAS identified 10 genetic loci reproducibly associated with HbA1c. Six are novel and seven map to loci where rarer variants cause hereditary anemias and iron storage disorders. Common variants at these loci likely influence HbA1c levels via erythrocyte biology, and confer a small but detectable reclassification of diabetes diagnosis by HbA1c