671 research outputs found

    Loop and surface operators in N=2 gauge theory and Liouville modular geometry

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    Recently, a duality between Liouville theory and four dimensional N=2 gauge theory has been uncovered by some of the authors. We consider the role of extended objects in gauge theory, surface operators and line operators, under this correspondence. We map such objects to specific operators in Liouville theory. We employ this connection to compute the expectation value of general supersymmetric 't Hooft-Wilson line operators in a variety of N=2 gauge theories.Comment: 60 pages, 11 figures; v3: further minor corrections, published versio

    Epstein-Barr Virus and p16INK4A Methylation in Squamous Cell Carcinoma and Precancerous Lesions of the Cervix Uteri

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    Methylation of p16 is an important mechanism in cervical carcinogenesis. However, the relationship between cervical squamous cell carcinoma (SCC) and Epstein-Barr virus (EBV) remains controversial. Here, we explored whether EBV infection and/or p16 gene inactivation would play any role in cervical carcinogenesis. Eighty-two specimens included 41 invasive SCCs, 30 cervical intraepithelial neoplasm (CIN; CIN 1, 11 cases, CIN II, 3 cases, CIN III 16 cases) and 11 nonneoplastic cervices. EBV was detected by polymerase chain reaction (PCR) for EBNA-1 and in situ hybridization for EBER-1. The p16 methylation-status and the expression of p16 protein were studied by methylation-specific PCR and immunohistochemistry, respectively. The materials were divided into four groups: 1) nonneoplastic cervices, 2) CIN I, 3) CIN II-III and 4) invasive SCCs. p16 methylation and p16 immunoexpressions increased in CIN and invasive SCCs than nonneoplastic tissue. p16-methylation and p16-immunoreactivities were higher in the EBV-positive group (p=0.009, p<0.001) than in the EBV-negative group. EBV was detected more frequently in CIN and SCCs than nonneoplastic cervices. In conclusion, a correlation between p16 methylation, p16 immunoreactivity and the detection of EBV strongly suggested that the cooperation of EBV and p16 gene may play a synergic effect on cell cycle deregulation

    Development of a specific fluorescent phage endolysin for in situ detection of Clostridium species associated with cheese spoilage

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    Late blowing defect (LBD) is a major cause of spoilage in cheeses, caused by the growth of Clostridium spp. in the cheese matrix. We investigated the application of CTP1L, a bacteriophage endolysin active against Clostridium tyrobutyricum, and its enzymatically active and cell wall-binding domains (EAD and CBD) attached to green fluorescent protein (GFP) to detect dairy-related Clostridium species by fluorescence microscopy. GFP-CTP1L and GFP-CBD demonstrated specificity for Clostridium spp. by labelling 15 and 17 of 20 Clostridium strains, respectively, but neither bound to other members of the cheese microbiota. However, GFP-EAD did not label any Clostridium strain tested. Unexpectedly, GFP-CTP1L and GFP-CBD were also able to bind to clostridial spores. In addition, GFP-CBD allowed us to visualize the vegetative cells of C. tyrobutyricum directly in the matrix of a LBD cheese. Site-directed mutants of GFP-CTP1L and GFP-CBD were made to examine the amino acids involved in binding and oligomer formation. Oligomerization was not essential for binding, but specific mutations in the CBD which affected oligomer formation also affected binding and lytic activity. We conclude that GFP-CTP1L and GFP-CBD could be good biomarkers for rapid detection of Clostridium spores in milk, so measures can be taken for the prevention of LBD in cheese, and also provide effective tools to study the development of Clostridium populations during cheese ripening

    Organism-sediment interactions govern post-hypoxia recovery of ecosystem functioning

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    Hypoxia represents one of the major causes of biodiversity and ecosystem functioning loss for coastal waters. Since eutrophication-induced hypoxic events are becoming increasingly frequent and intense, understanding the response of ecosystems to hypoxia is of primary importance to understand and predict the stability of ecosystem functioning. Such ecological stability may greatly depend on the recovery patterns of communities and the return time of the system properties associated to these patterns. Here, we have examined how the reassembly of a benthic community contributed to the recovery of ecosystem functioning following experimentally-induced hypoxia in a tidal flat. We demonstrate that organism-sediment interactions that depend on organism size and relate to mobility traits and sediment reworking capacities are generally more important than recovering species richness to set the return time of the measured sediment processes and properties. Specifically, increasing macrofauna bioturbation potential during community reassembly significantly contributed to the recovery of sediment processes and properties such as denitrification, bedload sediment transport, primary production and deep pore water ammonium concentration. Such bioturbation potential was due to the replacement of the small-sized organisms that recolonised at early stages by large-sized bioturbating organisms, which had a disproportionately stronger influence on sediment. This study suggests that the complete recovery of organism-sediment interactions is a necessary condition for ecosystem functioning recovery, and that such process requires long periods after disturbance due to the slow growth of juveniles into adult stages involved in these interactions. Consequently, repeated episodes of disturbance at intervals smaller than the time needed for the system to fully recover organism-sediment interactions may greatly impair the resilience of ecosystem functioning.

    Factors to Predict Positive Results of Gonadotropin Releasing Hormone Stimulation Test in Girls with Suspected Precocious Puberty

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    Sometimes, the clinical findings and the results of the gonadotropin-releasing hormone (GnRH) stimulation test are inconsistent in girls with early breast development and bone age advancement. We aimed to investigate the factors predicting positive results of the GnRH stimulation test in girls with suspected central precocious puberty (CPP). We reviewed the records of 574 girls who developed breast budding before the age of 8 yr and underwent the GnRH stimulation test under the age of 9 yr. Positive results of the GnRH stimulated peak luteinizing hormone (LH) level were defined as 5 IU/L and over. Girls with the initial positive results (n = 375) showed accelerated growth, advanced bone age and higher serum basal LH, follicle-stimulating hormone, and estradiol levels, compared to those with the initial negative results (n = 199). Girls with the follow-up positive results (n = 64) showed accelerated growth and advanced bone age, compared to those with the follow-up negative results. In the binary logistic regression, the growth velocity ratio was the most significant predictive factor of positive results. We suggest that the rapid growth velocity is the most useful predictive factor for positive results in the GnRH stimulation test in girls with suspected precocious puberty

    Interview Language: A Proxy Measure for Acculturation Among Asian Americans in a Population-Based Survey

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    We examined health status and access to care among Asian Americans by the following acculturation indicators: nativity, percent lifetime in the US, self-rated English proficiency, and interview language, to assess whether any measure better distinguishes acculturation. Data from the 2003 California Health Interview Survey were used to study the sample of 4,170 US-born and foreign-born Asians by acculturation indicators. We performed t-tests to compare differences in demographics, health status and behaviors, and access to care between the foreign-born and US-born Asians, and between various classifications within foreign-born and the US-born Asian group. Our results showed that foreign-born Asians who interviewed in English more closely resembled US-born Asians than foreign-born Asians who interviewed in languages other than English. Compared to interview language, dichotomizing the sample by other acculturation indicators showed smaller differences between the divided groups. Interview language may serve as a better measure for acculturation especially among foreign-born populations with a high proportion of limited English proficiency. In immigrant public health research studies, interview language may be used as an important covariate for health disparities

    Benefits and risks of the hormetic effects of dietary isothiocyanates on cancer prevention

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    The isothiocyanate (ITC) sulforaphane (SFN) was shown at low levels (1-5 µM) to promote cell proliferation to 120-143% of the controls in a number of human cell lines, whilst at high levels (10-40 µM) it inhibited such cell proliferation. Similar dose responses were observed for cell migration, i.e. SFN at 2.5 µM increased cell migration in bladder cancer T24 cells to 128% whilst high levels inhibited cell migration. This hormetic action was also found in an angiogenesis assay where SFN at 2.5 µM promoted endothelial tube formation (118% of the control), whereas at 10-20 µM it caused significant inhibition. The precise mechanism by which SFN influences promotion of cell growth and migration is not known, but probably involves activation of autophagy since an autophagy inhibitor, 3-methyladenine, abolished the effect of SFN on cell migration. Moreover, low doses of SFN offered a protective effect against free-radical mediated cell death, an effect that was enhanced by co-treatment with selenium. These results suggest that SFN may either prevent or promote tumour cell growth depending on the dose and the nature of the target cells. In normal cells, the promotion of cell growth may be of benefit, but in transformed or cancer cells it may be an undesirable risk factor. In summary, ITCs have a biphasic effect on cell growth and migration. The benefits and risks of ITCs are not only determined by the doses, but are affected by interactions with Se and the measured endpoint

    Arabidopsis AtVPS15 is essential for pollen development and germination through modulating phosphatidylinositol 3-phosphate formation

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    Arabidopsis thaliana phosphatidylinositol 3-kinase (AtVPS34) functions in the development and germination of pollen by catalyzing the biosynthesis of phosphatidylinositol 3-phosphate (PI3P). In yeast, Vps15p is required for the membrane targeting and activity of Vps34. The expression of Arabidopsis thaliana VPS15 (AtVPS15), an ortholog of yeast Vps15, is mainly detected in pollen grains and pollen tubes. To determine its role in pollen development and pollen tube growth, we attempted to isolate the T-DNA insertion mutants of AtVPS15; however, homozygous lines of atvps15 were not obtained from the progeny of atvps15/+ heterozygotes. Genetic analysis revealed that the abnormal segregation is due to the failure of transmission of the atvps15 allele through pollen. Most pollen grains from the atvps15/+ genotype are viable, with normal exine structure and nuclei, but some mature pollen grains are characterized with unusual large vacuoles that are not observed in pollen grains from the wild AtVPS15 genotype. The germination ratio of pollen from the atvps15/+ genotype is about half when compared to that from the wild AtVPS15 genotype. When supplied with PI3P, in vitro pollen germination of the atvps15/+ genotype is greatly improved. Presumably, AtVPS15 functions in pollen development and germination by regulating PI3P biosynthesis in Arabidopsis

    A Specific Activity-Based Probe to Monitor Family GH59 Galactosylceramidase, the Enzyme Deficient in Krabbe Disease

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    Galactosylceramidase (GALC) is the lysosomal β-galactosidase responsible for the hydrolysis of galactosylceramide. Inherited deficiency in GALC causes Krabbe disease, a devastating neurological disorder characterized by accumulation of galactosylceramide and its deacylated counterpart, the toxic sphingoid base galactosylsphingosine (psychosine). We report the design and application of a fluorescently tagged activity-based probe (ABP) for the sensitive and specific labeling of active GALC molecules from various species. The probe consists of a β-galactopyranose-configured cyclophellitol-epoxide core, conferring specificity for GALC, equipped with a BODIPY fluorophore at C6 that allows visualization of active enzyme in cells and tissues. Detection of residual GALC in patient fibroblasts holds great promise for laboratory diagnosis of Krabbe disease. We further describe a procedure for in situ imaging of active GALC in murine brain by intra-cerebroventricular infusion of the ABP. In conclusion, this GALC-specific ABP should find broad applications in diagnosis, drug development, and evaluation of therapy for Krabbe disease

    Macrocytosis during sunitinib treatment predicts progression-free survival in patients with metastatic renal cell carcinoma

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    Sunitinib, a multi-targeted receptor tyrosine kinase inhibitor, is a first-line treatment for metastatic renal cell carcinoma (mRCC) in patients in ‘low’ and ‘intermediate’ Memorial Sloan Kettering Cancer Center and Heng risk groups. Disruptions of hematopoiesis, such as anemia, neutropenia, and thrombocytopenia, are typically observed during sunitinib treatment. When it comes to RBC parameters, an increase in mean cell volume (MCV) tends to occur, meeting the criteria for macrocytosis in some patients (MCV > 100 fL). We examined changes in RBC parameters of 27 mRCC patients treated with sunitinib (initial dose of 50 mg/day, 6-week treatment: 4 weeks on, 2 weeks off) and correlated them with progression-free survival time (PFS). Patients who had macrocytosis after 3 treatment cycles had significantly longer PFS than those whose MCV stayed less than 100 fL (not reached vs. 11.2 months, p < 0.001). We also found a correlation between MCV values after the first and third treatment cycles and the risk of progression: HR of 0.9 (0.81–0.99) and 0.76 (0.65–0.90) per 1 fL increase in MCV, respectively. The mechanism of MCV elevation during sunitinib treatment has not yet been fully explained. One of the probable causes is sunitinib’s inhibitory influence on c-Kit kinase, as is the case with imatinib. For mRCC patients, this phenomenon could help predict PFS, but since our sample was small, further studies are essential
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