245 research outputs found

    ON THE INCIDENCE OF THE DIFFERENT FORMS OF PRIMARY GLAUCOMA

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    Phosphocholine – an agonist of metabotropic but not of ionotropic functions of alpha9-containing nicotinic acetylcholine receptors

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    We demonstrated previously that phosphocholine and phosphocholine-modified macromolecules efficiently inhibit ATP-dependent release of interleukin-1beta from human and murine monocytes by a mechanism involving nicotinic acetylcholine receptors (nAChR). Interleukin-1beta is a potent pro-inflammatory cytokine of innate immunity that plays pivotal roles in host defence. Control of interleukin-1beta release is vital as excessively high systemic levels cause life threatening inflammatory diseases. In spite of its structural similarity to acetylcholine, there are no other reports on interactions of phosphocholine with nAChR. In this study, we demonstrate that phosphocholine inhibits ion-channel function of ATP receptor P2X7 in monocytic cells via nAChR containing alpha9 and alpha10 subunits. In stark contrast to choline, phosphocholine does not evoke ion current responses in Xenopus laevis oocytes, which heterologously express functional homomeric nAChR composed of alpha9 subunits or heteromeric receptors containing alpha9 and alpha10 subunits. Preincubation of these oocytes with phosphocholine, however, attenuated choline-induced ion current changes, suggesting that phosphocholine may act as a silent agonist. We conclude that phophocholine activates immuno-modulatory nAChR expressed by monocytes but does not stimulate canonical ionotropic receptor functions

    Identification of immunogenic candidate for new serological tests for Brucella melitensis by a proteomic approach.

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    Background: The diagnosis of brucellosis by serological tests is based on antigen suspensions derived from smooth lipopolysaccharide extracts, which can give false-positive results linked to cross-reactivity with other Gram-negative microorganisms, especially Yersinia enterocolitica O:9 and Escherichia coli O157:H7. Objective: The objective of the present study was the characterization by proteomic analysis of specific immunogenic proteins not associated with smooth lipopolysaccharide to improve the diagnostic tests used in the ovine brucellosis eradication programs. Methods: The serum from a sheep positive to Brucella melitensis was treated to eliminate all antibodies against such lipopolysaccharides and highlight the reaction towards the immunoreactive proteins in western blotting. Results: The immunoreactive bands were identified by nLC-MS/MS, and through bioinformatics tools, it was possible to select 12 potential candidates as protein antigens specific for Brucella melitensis. Conclusion: The detection of new antigens not subjected to cross-reactivity with other Gram-negative microorganisms can offer additional tools for the serological diagnosis of such diseases

    Vibrational circular dichroism signature of hemiprotonated intercalated four-stranded i-DNA

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    Abstract The four-stranded intercalated DNA structure exemplified by the oligonucleotide 5V-d(CCCCCCCCCCCC) (d(C) 12 ) was studied at acidic pH by infrared absorption (IR) and vibrational circular dichroism (VCD) spectroscopy and compared with spectra of the same oligonucleotide at neutral pH to establish distinct VCD markers for the intercalation motif. The most striking feature is a new absorption at 1694 cm À 1 and its corresponding VCD couplet with reversed sign. These are unique for the intercalated structure and have not been observed for other parallel stranded duplexes. Significant characteristic features resulting from the spatial arrangement of the sugar-phosphate backbone are also clearly present for d(C) 12 at acidic pH. An extensive network of CH. . .O bonds twists the backbone such that multiple through-space vibrational coupling occurs among neighbouring sugar-phosphate residues resulting in unusual VCD signals.

    A Minimal Threshold of c-di-GMP Is Essential for Fruiting Body Formation and Sporulation in Myxococcus xanthus

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    Generally, the second messenger bis-(3’-5’)-cyclic dimeric GMP (c-di-GMP) regulates the switch between motile and sessile lifestyles in bacteria. Here, we show that c-di-GMP is an essential regulator of multicellular development in the social bacterium Myxococcus xanthus. In response to starvation, M. xanthus initiates a developmental program that culminates in formation of spore-filled fruiting bodies. We show that c-di-GMP accumulates at elevated levels during development and that this increase is essential for completion of development whereas excess c-di-GMP does not interfere with development. MXAN3735 (renamed DmxB) is identified as a diguanylate cyclase that only functions during development and is responsible for this increased c-di-GMP accumulation. DmxB synthesis is induced in response to starvation, thereby restricting DmxB activity to development. DmxB is essential for development and functions downstream of the Dif chemosensory system to stimulate exopolysaccharide accumulation by inducing transcription of a subset of the genes encoding proteins involved in exopolysaccharide synthesis. The developmental defects in the dmxB mutant are non-cell autonomous and rescued by co-development with a strain proficient in exopolysaccharide synthesis, suggesting reduced exopolysaccharide accumulation as the causative defect in this mutant. The NtrC-like transcriptional regulator EpsI/Nla24, which is required for exopolysaccharide accumulation, is identified as a c-diGMP receptor, and thus a putative target for DmxB generated c-di-GMP. Because DmxB can be—at least partially—functionally replaced by a heterologous diguanylate cyclase, these results altogether suggest a model in which a minimum threshold level of c-di-GMP is essential for the successful completion of multicellular development in M. xanthus

    Burden of liver disease progression in hospitalized patients with type 2 diabetes mellitus

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    BACKGROUND AND AIMS: There are uncertainties on the burden of liver disease in patients with type-2 diabetes (T2D). METHODS: We measured adjusted hazard ratios of liver disease progression to hepatocellular cancer and/or decompensated cirrhosis in a 2010-2020 retrospective, bicentric, longitudinal, cohort of 52,066 hospitalized patients with T2D. RESULTS: Mean age was 64±14 years and 58% were men. Alcohol use disorders accounted for 57% of liver-related complications and were associated with all liver-related risk factors. Non-metabolic liver-related risk factors accounted for 37% of the liver burden. T2D control was not associated with liver disease progression. The incidence (95% confidence interval) of liver-related complications and of competing mortality were 3.9 (3.5-4.3) and 27.8 (26.7-28.9) per 1000 person-years at risk, respectively. The cumulative incidence of liver disease progression exceeded the cumulative incidence of competing mortality only in the presence of a well-identified risk factors of liver disease progression, including alcohol use. The incidence of hepatocellular cancer was 0.3 (95% CI, 0.1-0.5) per 1000 person-year in patients with obesity and it increased with age. The adjusted hazard ratios of liver disease progression were 55.7 (40.5-76.6), 3.5 (2.3-5.2), 8.9 (6.9-11.5), and 1.5 (1.1-2.1), for alcoholic liver disease, alcohol use disorders without alcoholic liver disease, non-metabolic liver-related risk factors, and obesity, respectively. The attributable fractions of alcohol use disorders, non-metabolic liver risk-related risk factors, and obesity to the liver burden were 55%, 14%, and 7%, respectively. CONCLUSIONS: In this analysis of data from two hospital-based cohorts of patients with T2D, alcohol use disorders, rather than obesity, contributed to most of the liver burden. These results suggest that patients with T2D should be advised to drink minimal amounts of alcohol. LAY SUMMARY: • There is uncertainty on the burden of liver-related complications in patients with type-2 diabetes • We studied the risks of liver cancer and complications of liver disease in over 50,000 patients with type-2 diabetes • We found that alcohol was the main factor associated with complications of liver disease • This finding has major implications on the alcohol advice given to patients with type-2 diabetes

    Step bunching with both directions of the current: Vicinal W(110) surfaces versus atomistic scale model

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    We report for the first time the observation of bunching of monoatomic steps on vicinal W(110) surfaces induced by step up or step down currents across the steps. Measurements reveal that the size scaling exponent {\gamma}, connecting the maximal slope of a bunch with its height, differs depending on the current direction. We provide a numerical perspective by using an atomistic scale model with a conserved surface flux to mimic experimental conditions, and also for the first time show that there is an interval of parameters in which the vicinal surface is unstable against step bunching for both directions of the adatom drift.Comment: 17 pages, 10 figure

    A Bound on the Flux of Magnetic Monopoles from Catalysis of Nucleon Decay in White Dwarfs

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    Catalysis of nucleon decay in white dwarfs is used to constrain the abundance of magnetic monopoles arising from Grand Unified Theories. Recent discoveries of the dimmest white dwarf ever observed, WD 1136-286 with L=104.94LL = 10^{-4.94} L_{\odot}, place limits on the monopole flux. An abundance of monopoles greater than the new bound would heat this star to a luminosity higher than what is observed. The new bound is (F/(F/cm 2^{-2} s1^{-1} sr1^{-1}) (συ/1028cm2)<1.3×1020(υ/103c)2(\sigma \upsilon/10^{-28} cm^2) < 1.3 \times 10^{-20} (\upsilon/10^{-3}c)^2, where υ\upsilon is the monopole velocity. The limit is improved by including the monopoles captured by the main-sequence progenitor of the white dwarf: (F/(F/cm 2^{-2} s1^{-1} sr1^{-1}) (συ/1028cm2)<3.5(26)×1021(\sigma \upsilon /10^{-28} cm^2) < 3.5(26) \times 10^{-21} for 101710^{17} (101610^{16}) GeV monopoles. We also note that the dependence on monopole mass of flux bounds due to catalysis in neutron stars with main sequence accretion has previously been calculated incorrectly (previously the bound has been stated as F(συ/1028cm2)<1028F (\sigma \upsilon/10^{-28} cm^2) < 10^{-28} cm 2^{-2} s1^{-1} sr1^{-1}). We show that the correct bounds are somewhat weaker for monopole mass other than 101710^{17} GeV.Comment: 16 pages, 1 Postscript figur
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