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Find video protocols related to scientific articles indexed in Pubmed.
Insights on antioxidant assays for biological samples based on the reduction of copper complexes-the importance of analytical conditions.
Int J Mol Sci
PUBLISHED: 05-23-2014
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Total antioxidant capacity assays are recognized as instrumental to establish antioxidant status of biological samples, however the varying experimental conditions result in conclusions that may not be transposable to other settings. After selection of the complexing agent, reagent addition order, buffer type and concentration, copper reducing assays were adapted to a high-throughput scheme and validated using model biological antioxidant compounds of ascorbic acid, Trolox (a soluble analogue of vitamin E), uric acid and glutathione. A critical comparison was made based on real samples including NIST-909c human serum certified sample, and five study samples. The validated method provided linear range up to 100 µM Trolox, (limit of detection 2.3 µM; limit of quantification 7.7 µM) with recovery results above 85% and precision <5%. The validated developed method with an increased sensitivity is a sound choice for assessment of TAC in serum samples.
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CD4+ T-cell help enhances NK cell function following therapeutic HIV-1 vaccination.
J. Virol.
PUBLISHED: 05-14-2014
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Increasing data suggest that NK cells can mediate antiviral activity in HIV-1-infected humans, and as such, novel approaches harnessing the anti-HIV-1 function of both T cells and NK cells represent attractive options to improve future HIV-1 immunotherapies. Chronic progressive HIV-1 infection has been associated with a loss of CD4(+) T helper cell function and with the accumulation of anergic NK cells. As several studies have suggested that cytokines produced by CD4(+) T cells are required to enhance NK cell function in various infection models, we hypothesized that reconstitution of HIV-1-specific CD4(+) T-cell responses by therapeutic immunization would restore NK cell activity in infected individuals. Using flow cytometry, we examined the function of CD4(+) T cells and NK cells in response to HIV-1 in subjects with treated chronic HIV-1 infection before and after immunization with an adjuvanted HIV-1 Gp120/NefTat subunit protein vaccine candidate provided by GlaxoSmithKline. Vaccination induced an increased expression of interleukin-2 (IL-2) by Gp120-specific CD4(+) T cells in response to HIV-1 peptides ex vivo, which was associated with enhanced production of gamma interferon (IFN-?) by NK cells. Our data show that reconstitution of HIV-1-specific CD4(+) T-cell function by therapeutic immunization can enhance NK cell activity in HIV-1-infected individuals.
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A simple and rapid screening method for sulfonamides in honey using a flow injection system coupled to a liquid waveguide capillary cell.
Talanta
PUBLISHED: 01-03-2014
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A rapid and simple screening method was developed for the determination of sulfonamides in honey samples by flow injection analysis (FIA) coupled to a liquid waveguide capillary cell. The proposed method is based on the reaction between sulfonamides and p-dimethylaminocinnamaldehyde (p-DAC) in the presence of sodium dodecylsulate (SDS) in dilute acid medium (hydrochloric acid), with the reaction product being measured spectrophotometrically at ?(max) = 565 nm. Experimental design methodology was used to optimize the analytical conditions. The proposed technique was applied to the determination of sulfonamides (sulfaquinoxaline, sulfadimethoxine, and sulfathiazole) in honey samples, in a concentration range from 6.00 × 10(-3) to 1.15 × 10(-1)mg L(-1). The detection (LOD) and quantification (LOQ) limits were 1.66 × 10(-3) and 5.54 × 10(-3)mg L(-1), respectively. Positive and false positive samples were also analyzed by a confirmatory HPLC method. The proposed system enables the screening of sulfonamides in honey samples with a low number of false positive results, with fast response therefore offers a new tool for consumer protection.
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Regulatory T cells expanded from HIV-1-infected individuals maintain phenotype, TCR repertoire and suppressive capacity.
PLoS ONE
PUBLISHED: 01-01-2014
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While modulation of regulatory T cell (Treg) function and adoptive Treg transfer are being explored as therapeutic modalities in the context of autoimmune diseases, transplantation and cancer, their role in HIV-1 pathogenesis remains less well defined. Controversy persists regarding their beneficial or detrimental effects in HIV-1 disease, which warrants further detailed exploration. Our objectives were to investigate if functional CD4(+) Tregs can be isolated and expanded from HIV-1-infected individuals for experimental or potential future therapeutic use and to determine phenotype and suppressive capacity of expanded Tregs from HIV-1 positive blood and tissue. Tregs and conventional T cell controls were isolated from blood and gut-associated lymphoid tissue of individuals with HIV-1 infection and healthy donors using flow-based cell-sorting. The phenotype of expanded Tregs was assessed by flow-cytometry and quantitative PCR. T-cell receptor ß-chain (TCR-?) repertoire diversity was investigated by deep sequencing. Flow-based T-cell proliferation and chromium release cytotoxicity assays were used to determine Treg suppressive function. Tregs from HIV-1 positive individuals, including infants, were successfully expanded from PBMC and GALT. Expanded Tregs expressed high levels of FOXP3, CTLA4, CD39 and HELIOS and exhibited a highly demethylated TSDR (Treg-specific demethylated region), characteristic of Treg lineage. The TCRß repertoire was maintained following Treg expansion and expanded Tregs remained highly suppressive in vitro. Our data demonstrate that Tregs can be expanded from blood and tissue compartments of HIV-1+ donors with preservation of Treg phenotype, function and TCR repertoire. These results are highly relevant for the investigation of potential future therapeutic use, as currently investigated for other disease states and hold great promise for detailed studies on the role of Tregs in HIV-1 infection.
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Flow-injection spectrophotometric determination of bromate in bottled drinking water samples using chlorpromazine reagent and a liquid waveguide capillary cell.
Anal Sci
PUBLISHED: 05-14-2013
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In this work, aiming to develop a simple, inexpensive method for the determination of low bromate levels in water samples, a liquid waveguide capillary cell (LWCC) was coupled to a FIA system. The long optical path (100 cm) of the LWCC was used to improve the sensitivity and the limit of detection without resorting to any off-line or in-line preconcentration processes. The spectrophotometric determination was based on the oxidation of chlorpromazine by bromate in an acidic medium, resulting in the formation of a colored radical product. Sulfamic acid was added to the reagent for minimizing the interference of nitrite, and a chelating ion exchange resin was used to remove major cationic interferences. The developed system allowed the determination of bromate within the range between 1 - 20 ?g L(-1) with a detection limit of 0.2 ?g L(-1).
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Chemical and colloidal stability of carboxylated core-shell magnetite nanoparticles designed for biomedical applications.
Int J Mol Sci
PUBLISHED: 05-02-2013
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Despite the large efforts to prepare super paramagnetic iron oxide nanoparticles (MNPs) for biomedical applications, the number of FDA or EMA approved formulations is few. It is not known commonly that the approved formulations in many instances have already been withdrawn or discontinued by the producers; at present, hardly any approved formulations are produced and marketed. Literature survey reveals that there is a lack for a commonly accepted physicochemical practice in designing and qualifying formulations before they enter in vitro and in vivo biological testing. Such a standard procedure would exclude inadequate formulations from clinical trials thus improving their outcome. Here we present a straightforward route to assess eligibility of carboxylated MNPs for biomedical tests applied for a series of our core-shell products, i.e., citric acid, gallic acid, poly(acrylic acid) and poly(acrylic acid-co-maleic acid) coated MNPs. The discussion is based on physicochemical studies (carboxylate adsorption/desorption, FTIR-ATR, iron dissolution, zeta potential, particle size, coagulation kinetics and magnetization measurements) and involves in vitro and in vivo tests. Our procedure can serve as an example to construct adequate physico-chemical selection strategies for preparation of other types of core-shell nanoparticles as well.
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Dysregulated Tim-3 expression on natural killer cells is associated with increased Galectin-9 levels in HIV-1 infection.
Retrovirology
PUBLISHED: 02-22-2013
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Natural killer (NK) cells constitutively express high levels of Tim-3, an immunoregulatory molecule recently proposed to be a marker for mature and functional NK cells. Whether HIV-1 infection modulates the expression of Tim-3 on NK cells, or the levels of its ligand Galectin-9 (Gal-9), and how signaling through these molecules affects the NK cell response to HIV-1 remains inadequately understood.
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Effects of IgM-enriched immunoglobulin therapy in septic-shock-induced multiple organ failure: pilot study.
J Anesth
PUBLISHED: 01-12-2013
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Mortality due to septic-shock-induced respiratory failure remains high. A recent meta-analysis suggested that IgM-enriched immunoglobulin treatment may be beneficial in these patients. In this prospective randomised controlled pilot study we investigated the effects of IgM-enriched immunoglobulin treatment in patients with early septic shock accompanied by severe respiratory failure. 33 patients were randomly allocated to receive 5 ml/kg (predicted body weight) IgM-enriched immunoglobulin (16 patients) or placebo (17 patients), respectively, via 8 h IV-infusion for three consecutive days. Daily Multiple Organ Dysfunction Scores (MODS) were calculated. Serum C-reactive protein (CRP) and procalcitonin (PCT) levels were monitored daily. For statistical analysis two-way ANOVA was used. Daily MODS showed ongoing multiple system organ failure without significant resolution during the 8 days. Median length of ICU stay, mechanical ventilation, vasopressor support during the ICU stay and 28-day mortality were nearly identical in the two groups. Serum PCT levels showed no significant difference between the two groups, however, CRP levels were significantly lower in the IgM-enriched immunoglobulin group on days 4, 5 and 6, respectively. In this study the use of IgM-enriched immunoglobulin preparation failed to produce any improvement in the organ dysfunction as compared to standard sepsis therapy.
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Comparative Network Analysis of Preterm vs. Full-Term Infant-Mother Interactions.
PLoS ONE
PUBLISHED: 01-01-2013
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Several studies have reported that interactions of mothers with preterm infants show differential characteristics compared to that of mothers with full-term infants. Interaction of preterm dyads is often reported as less harmonious. However, observations and explanations concerning the underlying mechanisms are inconsistent. In this work 30 preterm and 42 full-term mother-infant dyads were observed at one year of age. Free play interactions were videotaped and coded using a micro-analytic coding system. The video records were coded at one second resolution and studied by a novel approach using network analysis tools. The advantage of our approach is that it reveals the patterns of behavioral transitions in the interactions. We found that the most frequent behavioral transitions are the same in the two groups. However, we have identified several high and lower frequency transitions which occur significantly more often in the preterm or full-term group. Our analysis also suggests that the variability of behavioral transitions is significantly higher in the preterm group. This higher variability is mostly resulted from the diversity of transitions involving non-harmonious behaviors. We have identified a maladaptive pattern in the maternal behavior in the preterm group, involving intrusiveness and disengagement. Application of the approach reported in this paper to longitudinal data could elucidate whether these maladaptive maternal behavioral changes place the infant at risk for later emotional, cognitive and behavioral disturbance.
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Determination of glyphosate in water samples by multi-pumping flow system coupled to a liquid waveguide capillary cell.
Anal Sci
PUBLISHED: 10-12-2011
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A simple screening method was developed for the determination of glyphosate in water samples using a multi-pumping flow system. The proposed method is based on the reaction between glyphosate and p-dimethylaminocinnamaldehyde (p-DAC), in an acid medium where the reaction product can be measured spectrophotometrically at ?(max) = 495 nm. An experimental design methodology was used to optimize the measurement conditions. The proposed method was applied to the determination of glyphosate in water samples in a concentration range from 0.5 to 10 µg mL(-1). The limit of detection and quantification were 0.17 and 0.53 µg mL(-1), respectively. The results obtained (88.5 to 104.5%) in recovery studies for the determination of glyphosate in different water samples indicated good accuracy and no matrix effect for the developed method. Samples were also analyzed by a confirmatory HPLC method, and agreement within the two set of results was found.
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Determination of total protein content in white wines by solid phase spectrometry in a SI-LOV system.
Talanta
PUBLISHED: 09-23-2011
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Although present at low concentration in wine samples, proteins, have considerable technological importance, due to their capability of haze formation. The present work presents a methodology for the quantification of total protein in white wine in a sequential injection lab-on-valve system, exploiting the bead injection concept for solid phase extraction with spectrophotometric detection. The method is based on the retention of the proteins in the solid support, NTA (nitrilotriacetic acid) superflow beads, charged by Cu(2+). The change in the absorbance is monitored at 500nm at the surface of the beads after addition of the Folin-Ciocalteus reagent (FCr). The developed method presented a sample consumption of 400?L per assay and a consumption of FCr and Cu(2+) solution of 25?L and 100?L per assay, respectively. It was possible to achieve a linear range up to 0.30g/L with a limit of detection and quantification of 0.03 and 0.10g/L, respectively. The proposed method was successfully applied to white wine samples.
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[Attitudes of freshman medical students towards education in communication skills].
Orv Hetil
PUBLISHED: 09-08-2011
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In their institute authors teach medical communication skills in three languages (Hungarian, English and German) for medical students in the first year of their studies. In order to improve teaching methods, authors wanted to explore the attitudes of students towards the communication skills learning. For this purpose authors applied the Communication Skills Attitudes Scale created by Rees et al., which is an internationally accepted and well adaptable instrument. Aims: In this survey authors wanted to validate the Hungarian and German version of the Communication Skills Attitudes Scale. In addition, their aim was to analyze possible differences between the attitudes of each of the three medical teaching programs. Methods: Questionnaires were filled anonymously at the beginning of the practices. Principal component analysis with varimax rotation was performed to evaluate the attitudes using the SPSS 10.5 version for analysis. Results: Authors created a model consisting of 7 factors. Factors were the following: 1: respect and interpersonal skills; 2: learning; 3: importance of communication within medical profession; 4: excuse; 5: counter; 6: exam; 7: overconfidence. It was found that students had mainly positive attitudes. Except the learning factor, all other factors showed significant differences between the three medical teaching programs. Conclusions: although students had mainly positive attitudes toward learning communication skills, there were negative attitudes which can be partly modified by improving the teaching methods. However, results may create a proper base for further research to help improving communication skills teaching methods of the authors.
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pH-driven physicochemical conformational changes of single-layer graphene oxide.
Chem. Commun. (Camb.)
PUBLISHED: 08-01-2011
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Single-layer graphene oxides (SLGOs) undergo morphological changes depending on the pH of the system and may account for restricted chemical reactivity. Herein, SLGO may also capture nanoparticles through layering and enveloping when the pH is changed, demonstrating potential usefulness in drug delivery or waste material capture.
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[Further examination of the Strengths and Difficulties Questionnaire (SDQ-Magy) in a community sample of young adolescents].
Psychiatr Hung
PUBLISHED: 07-28-2011
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The Strengths and Difficulties Questionnaire (SDQ-Magy) is a brief instrument suitable for assessing and screening childhood behavior and mental problems, available in parent and teacher, and from 11 years of age, self-report versions. The aim of the present study was to extend our previous investigation in a community sample to an older age group, to examine its psychometric properties, and to assess cross-informant agreements and differences, effects of gender and age, as well as to determine cut-off points between normal and abnormal scores within the community sample.
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[Attitude of medical students to smoking and to the regulatory measures related to smoking].
Orv Hetil
PUBLISHED: 05-07-2011
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In some countries strict tobacco control measures successfully reduced the number of smokers. Although these measures do not have immediate effects, they may serve as investments in the future healthcare. Health care experts should take part actively in the decision making.
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Development of a flow method for the determination of phosphate in estuarine and freshwaters--comparison of flow cells in spectrophotometric sequential injection analysis.
Anal. Chim. Acta
PUBLISHED: 03-19-2011
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A sequential injection system with dual analytical line was developed and applied in the comparison of two different detection systems viz; a conventional spectrophotometer with a commercial flow cell, and a multi-reflective flow cell coupled with a photometric detector under the same experimental conditions. The study was based on the spectrophotometric determination of phosphate using the molybdenum-blue chemistry. The two alternative flow cells were compared in terms of their response to variation of sample salinity, susceptibility to interferences and to refractive index changes. The developed method was applied to the determination of phosphate in natural waters (estuarine, river, well and ground waters). The achieved detection limit (0.007 ?M PO(4)(3-)) is consistent with the requirement of the target water samples, and a wide quantification range (0.024-9.5 ?M) was achieved using both detection systems.
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Epithelial adhesion molecules can inhibit HIV-1-specific CD8? T-cell functions.
Blood
PUBLISHED: 03-14-2011
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Under persistent antigenic stimulation, virus-specific CD8? T cells become increasingly dysfunctional and up-regulate several inhibitory molecules such as killer lectin-like receptor G1 (KLRG1). Here, we demonstrate that HIV-1 antigen-specific T cells from subjects with chronic-progressive HIV-1 infection have significantly elevated KLRG1 expression (P < .001); show abnormal distribution of E-cadherin, the natural ligand of KLRG1, in the intestinal mucosa; and have elevated levels of systemic soluble E-cadherin (sE-cadherin) that significantly correlate with HIV-1 viral load (R = 0.7, P = .004). We furthermore demonstrate that in the presence of sE-cadherin, KLRG1(hi) HIV-1-specific CD8? T cells are impaired in their ability to respond by cytokine secretion on antigenic stimulation (P = .002) and to inhibit viral replication (P = .03) in vitro. Thus, these data suggest a critical mechanism by which the disruption of the intestinal epithelium associated with HIV-1 leads to increased systemic levels of sE-cadherin, which inhibits the effector functions of KLRG1(hi)-expressing HIV-1-specific CD8? T cells systemically.
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[Medical students smoking habits and attitudes about cessation].
Orv Hetil
PUBLISHED: 03-11-2011
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Medical years are very important in shaping the attitudes of future doctors. It is proven that doctors who smoke do not advise their patient to stop smoking. We have to know the students smoking habits and attitudes about smoking cessation to make them interested in the fight against tobacco.
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Exploiting the bead injection LOV approach to carry out spectrophotometric assays in wine: application to the determination of iron.
Talanta
PUBLISHED: 01-14-2011
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A sequential injection lab-on-valve (SI-LOV) system was used to develop a new methodology for the determination of iron in wine samples exploiting the bead injection (BI) concept for solid phase extraction and spectrophotometric measurement. Nitrilotriacetic Acid (NTA) Superflow resin was used to build the bead column of the flow through sensor. The iron (III) ions were retained by the bead column and react with SCN(-) producing an intense red colour. The change in absorbance was monitored spectrophotometrically on the optosensor at 480 nm. It was possible to achieve a linear range of 0.09-5.0 mg L(-1) of iron, with low sample and reagent consumption; 500 ?L of sample, 15 ?mol of SCN(-), and 9 ?mol of H(2)O(2), per assay. The proposed method was successfully applied to the determination of iron in wine, with no previous treatment other than dilution, and to other food samples.
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Spectrophotometric determination of zinc and copper in a multi-syringe flow injection analysis system using a liquid waveguide capillary cell: application to natural waters.
Talanta
PUBLISHED: 01-04-2011
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This work exploits a multi-syringe injection analysis (MSFIA) system coupled with a long liquid waveguide capillary cell for the spectrophotometric determination of zinc and copper in waters. A liquid waveguide capillary cell (1.0m pathlength, 550 ?m i.d. and 250 ?L internal volume) was used to enhance the sensitivity of the detection. The determination for both ions is based on a colorimetric reaction with zincon at different pH values. The developed methodology compares favourably with other previously described procedures, as it allows to reach low detection limits for both cations (LODs of 0.1 and 2 ?g L(-1), for copper and zinc, respectively), without the need for any pre-concentration step. The system also provided a linear response up to 100 ?g L(-1) with a high throughput (43 h(-1)) and low reagent consumption and effluent production. The developed work was applied to natural waters and three certified reference water samples.
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Decreased Fc receptor expression on innate immune cells is associated with impaired antibody-mediated cellular phagocytic activity in chronically HIV-1 infected individuals.
Virology
PUBLISHED: 01-03-2011
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In addition to neutralization, antibodies mediate other antiviral activities including antibody-dependent cellular phagocytosis (ADCP), antibody-dependent cellular cytotoxicity (ADCC), as well as complement deposition. While it is established that progressive HIV infection is associated with reduced ADCC and ADCP, the underlying mechanism for this loss of function is unknown. Here we report considerable changes in FcR expression over the course of HIV infection on both mDCs and monocytes, including elevated Fc?RI expression in acute HIV infection and reduced expression of Fc?RII and Fc?RIIIa in chronic HIV infection. Furthermore, selective blockade of Fc?RII alone was associated with a loss in ADCP activity, suggesting that Fc?RII plays a central role in modulating ADCP. Overall, HIV infection is associated with a number of changes in FcR expression on phagocytic cells that are associated with changes in their ability to respond to antibody-opsonized targets, potentially contributing to a failure in viral clearance in progressive HIV-1 infection.
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The major genetic determinants of HIV-1 control affect HLA class I peptide presentation.
, Florencia Pereyra, Xiaoming Jia, Paul J McLaren, Amalio Telenti, Paul I W de Bakker, Bruce D Walker, Stephan Ripke, Chanson J Brumme, Sara L Pulit, Mary Carrington, Carl M Kadie, Jonathan M Carlson, David Heckerman, Robert R Graham, Robert M Plenge, Steven G Deeks, Lauren Gianniny, Gabriel Crawford, Jordan Sullivan, Elena González, Leela Davies, Amy Camargo, Jamie M Moore, Nicole Beattie, Supriya Gupta, Andrew Crenshaw, Noel P Burtt, Candace Guiducci, Namrata Gupta, Xiaojiang Gao, Ying Qi, Yuko Yuki, Alicja Piechocka-Trocha, Emily Cutrell, Rachel Rosenberg, Kristin L Moss, Paul Lemay, Jessica O'Leary, Todd Schaefer, Pranshu Verma, Ildikó Tóth, Brian Block, Brett Baker, Alissa Rothchild, Jeffrey Lian, Jacqueline Proudfoot, Donna Marie L Alvino, Seanna Vine, Marylyn M Addo, Todd M Allen, Marcus Altfeld, Matthew R Henn, Sylvie Le Gall, Hendrik Streeck, David W Haas, Daniel R Kuritzkes, Gregory K Robbins, Robert W Shafer, Roy M Gulick, Cecilia M Shikuma, Richard Haubrich, Sharon Riddler, Paul E Sax, Eric S Daar, Heather J Ribaudo, Brian Agan, Shanu Agarwal, Richard L Ahern, Brady L Allen, Sherly Altidor, Eric L Altschuler, Sujata Ambardar, Kathryn Anastos, Ben Anderson, Val Anderson, Ushan Andrady, Diana Antoniskis, David Bangsberg, Daniel Barbaro, William Barrie, J Bartczak, Simon Barton, Patricia Basden, Nesli Basgoz, Suzane Bazner, Nicholaos C Bellos, Anne M Benson, Judith Berger, Nicole F Bernard, Annette M Bernard, Christopher Birch, Stanley J Bodner, Robert K Bolan, Emilie T Boudreaux, Meg Bradley, James F Braun, Jon E Brndjar, Stephen J Brown, Katherine Brown, Sheldon T Brown, Jedidiah Burack, Larry M Bush, Virginia Cafaro, Omobolaji Campbell, John Campbell, Robert H Carlson, J Kevin Carmichael, Kathleen K Casey, Chris Cavacuiti, Gregory Celestin, Steven T Chambers, Nancy Chez, Lisa M Chirch, Paul J Cimoch, Daniel Cohen, Lillian E Cohn, Brian Conway, David A Cooper, Brian Cornelson, David T Cox, Michael V Cristofano, George Cuchural, Julie L Czartoski, Joseph M Dahman, Jennifer S Daly, Benjamin T Davis, Kristine Davis, Sheila M Davod, Edwin DeJesus, Craig A Dietz, Eleanor Dunham, Michael E Dunn, Todd B Ellerin, Joseph J Eron, John J W Fangman, Claire E Farel, Helen Ferlazzo, Sarah Fidler, Anita Fleenor-Ford, Renee Frankel, Kenneth A Freedberg, Neel K French, Jonathan D Fuchs, Jon D Fuller, Jonna Gaberman, Joel E Gallant, Rajesh T Gandhi, Efrain Garcia, Donald Garmon, Joseph C Gathe, Cyril R Gaultier, Wondwoosen Gebre, Frank D Gilman, Ian Gilson, Paul A Goepfert, Michael S Gottlieb, Claudia Goulston, Richard K Groger, T Douglas Gurley, Stuart Haber, Robin Hardwicke, W David Hardy, P Richard Harrigan, Trevor N Hawkins, Sonya Heath, Frederick M Hecht, W Keith Henry, Melissa Hladek, Robert P Hoffman, James M Horton, Ricky K Hsu, Gregory D Huhn, Peter Hunt, Mark J Hupert, Mark L Illeman, Hans Jaeger, Robert M Jellinger, Mina John, Jennifer A Johnson, Kristin L Johnson, Heather Johnson, Kay Johnson, Jennifer Joly, Wilbert C Jordan, Carol A Kauffman, Homayoon Khanlou, Robert K Killian, Arthur Y Kim, David D Kim, Clifford A Kinder, Jeffrey T Kirchner, Laura Kogelman, Erna Milunka Kojic, P Todd Korthuis, Wayne Kurisu, Douglas S Kwon, Melissa Lamar, Harry Lampiris, Massimiliano Lanzafame, Michael M Lederman, David M Lee, Jean M L Lee, Marah J Lee, Edward T Y Lee, Janice Lemoine, Jay A Levy, Josep M Llibre, Michael A Liguori, Susan J Little, Anne Y Liu, Alvaro J Lopez, Mono R Loutfy, Dawn Loy, Debbie Y Mohammed, Alan Man, Michael K Mansour, Vincent C Marconi, Martin Markowitz, Rui Marques, Jeffrey N Martin, Harold L Martin, Kenneth Hugh Mayer, M Juliana McElrath, Theresa A McGhee, Barbara H McGovern, Katherine McGowan, Dawn McIntyre, Gavin X Mcleod, Prema Menezes, Greg Mesa, Craig E Metroka, Dirk Meyer-Olson, Andy O Miller, Kate Montgomery, Karam C Mounzer, Ellen H Nagami, Iris Nagin, Ronald G Nahass, Margret O Nelson, Craig Nielsen, David L Norene, David H O'Connor, Bisola O Ojikutu, Jason Okulicz, Olakunle O Oladehin, Edward C Oldfield, Susan A Olender, Mario Ostrowski, William F Owen, Eunice Pae, Jeffrey Parsonnet, Andrew M Pavlatos, Aaron M Perlmutter, Michael N Pierce, Jonathan M Pincus, Leandro Pisani, Lawrence Jay Price, Laurie Proia, Richard C Prokesch, Heather Calderon Pujet, Moti Ramgopal, Almas Rathod, Michael Rausch, J Ravishankar, Frank S Rhame, Constance Shamuyarira Richards, Douglas D Richman, Berta Rodés, Milagros Rodriguez, Richard C Rose, Eric S Rosenberg, Daniel Rosenthal, Polly E Ross, David S Rubin, Elease Rumbaugh, Luis Saenz, Michelle R Salvaggio, William C Sanchez, Veeraf M Sanjana, Steven Santiago, Wolfgang Schmidt, Hanneke Schuitemaker, Philip M Sestak, Peter Shalit, William Shay, Vivian N Shirvani, Vanessa I Silebi, James M Sizemore, Paul R Skolnik, Marcia Sokol-Anderson, James M Sosman, Paul Stabile, Jack T Stapleton, Sheree Starrett, Francine Stein, Hans-Jürgen Stellbrink, F Lisa Sterman, Valerie E Stone, David R Stone, Giuseppe Tambussi, Randy A Taplitz, Ellen M Tedaldi, William Theisen, Richard Torres, Lorraine Tosiello, Cécile Tremblay, Marc A Tribble, Phuong D Trinh, Alice Tsao, Peggy Ueda, Anthony Vaccaro, Emília Valadas, Thanes J Vanig, Isabel Vecino, Vilma M Vega, Wenoah Veikley, Barbara H Wade, Charles Walworth, Chingchai Wanidworanun, Douglas J Ward, Daniel A Warner, Robert D Weber, Duncan Webster, Steve Weis, David A Wheeler, David J White, Ed Wilkins, Alan Winston, Clifford G Wlodaver, Angelique van't Wout, David P Wright, Otto O Yang, David L Yurdin, Brandon W Zabukovic, Kimon C Zachary, Beth Zeeman, Meng Zhao.
Science
PUBLISHED: 11-04-2010
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Infectious and inflammatory diseases have repeatedly shown strong genetic associations within the major histocompatibility complex (MHC); however, the basis for these associations remains elusive. To define host genetic effects on the outcome of a chronic viral infection, we performed genome-wide association analysis in a multiethnic cohort of HIV-1 controllers and progressors, and we analyzed the effects of individual amino acids within the classical human leukocyte antigen (HLA) proteins. We identified >300 genome-wide significant single-nucleotide polymorphisms (SNPs) within the MHC and none elsewhere. Specific amino acids in the HLA-B peptide binding groove, as well as an independent HLA-C effect, explain the SNP associations and reconcile both protective and risk HLA alleles. These results implicate the nature of the HLA-viral peptide interaction as the major factor modulating durable control of HIV infection.
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Mutational escape in HIV-1 CTL epitopes leads to increased binding to inhibitory myelomonocytic MHC class I receptors.
PLoS ONE
PUBLISHED: 08-21-2010
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Escape mutations in HIV-1 cytotoxic T cell (CTL) epitopes can abrogate recognition by the TCR of HIV-1-specific CD8+ T cells, but may also change interactions with alternative MHC class I receptors. Here, we show that mutational escape in three HLA-A11-, B8- and B7- restricted immunodominant HIV-1 CTL epitopes consistently enhances binding of the respective peptide/MHC class I complex to Immunoglobulin-like transcript 4 (ILT4), an inhibitory myelomonocytic MHC class I receptor expressed on monocytes and dendritic cells. In contrast, mutational escape in an alternative immunodominant HLA-B57-restricted CTL epitope did not affect ILT4-mediated recognition by myelomonocytic cells. This suggests that in addition to abrogating recognition by HIV-1-specific CD8 T cells, mutational escape in some, but not all CTL epitopes may mediate important immunoregulatory effects by increasing binding properties to ILT4, and augmenting ILT4-mediated inhibitory effects of professional antigen-presenting cells.
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Soluble HLA-G inhibits myeloid dendritic cell function in HIV-1 infection by interacting with leukocyte immunoglobulin-like receptor B2.
J. Virol.
PUBLISHED: 08-11-2010
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Dendritic cells represent a specialized class of professional antigen-presenting cells that are responsible for priming and maintaining antigen-specific effector cell responses and regulating immune activation by cytokine secretion. In HIV-1 infection, myeloid dendritic cells are highly dysfunctional, but mechanisms contributing to their functional alterations are not well defined. Here, we show that soluble molecules of the nonclassical major histocompatibility complex class Ib (MHC-Ib) antigen HLA-G are highly upregulated in the plasma during progressive HIV-1 infection, while levels of membrane-bound HLA-G surface expression on dendritic cells, monocytes, and T cells only slightly differ among HIV-1 progressors, HIV-1 elite controllers, and HIV-1-negative persons. These elevated levels of soluble HLA-G in progressive HIV-1 infection likely result from increased secretion of intracellularly stored HLA-G molecules in monocytes and dendritic cells and contribute to a functional disarray of dendritic cells by inhibiting their antigen-presenting properties, while simultaneously enhancing their secretion of proinflammatory cytokines. Interestingly, we observed that these immunoregulatory effects of soluble HLA-G were mainly mediated by interactions with the myelomonocytic HLA class I receptor leukocyte immunoglobulin-like receptor B2 (LILRB2; ILT4), while binding of soluble HLA-G to its alternative high-affinity receptor, LILRB1 (ILT2), appeared to be less relevant for its immunomodulatory functions on dendritic cells. Overall, these results demonstrate a critical role for soluble HLA-G in modulating the functional characteristics of professional antigen-presenting cells in progressive HIV-1 infection and suggest that soluble HLA-G might represent a possible target for immunotherapeutic interventions in HIV-1-infected persons.
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Leukocyte immunoglobulin-like receptors maintain unique antigen-presenting properties of circulating myeloid dendritic cells in HIV-1-infected elite controllers.
J. Virol.
PUBLISHED: 07-14-2010
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Elite controllers maintain undetectable levels of HIV-1 replication in the absence of antiretroviral therapy, but the correlates of immune protection in this patient population are ill defined. Here, we demonstrate that in comparison to patients with progressive HIV-1 infection or healthy persons not infected with HIV-1, elite controllers have circulating myeloid dendritic cells with significantly increased antigen-presenting properties, while their ability to secrete proinflammatory cytokines is substantially diminished. This unique functional profile is associated with a distinct surface expression pattern of immunomodulatory leukocyte-immunoglobulin-like receptors (LILR) and a strong and selective upregulation of LILRB1 and LILRB3. Blockade of these two receptors by monoclonal antibodies or short interfering RNA (siRNA) abrogated the specific antigen-presenting properties of dendritic cells, implying an important regulatory role of these molecules. These data reveal previously unrecognized innate components of immune protection against HIV-1 in elite controllers and offer novel perspectives for the manipulation of host immunity for the prevention and treatment of HIV-1 infection.
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Transcriptional analysis of HIV-specific CD8+ T cells shows that PD-1 inhibits T cell function by upregulating BATF.
Nat. Med.
PUBLISHED: 07-13-2010
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CD8(+) T cells in chronic viral infections such as HIV develop functional defects including loss of interleukin-2 (IL-2) secretion and decreased proliferative potential that are collectively termed exhaustion. Exhausted T cells express increased amounts of multiple inhibitory receptors, such as programmed death-1 (PD-1), that contribute to impaired virus-specific T cell function. Although reversing PD-1 inhibition is therefore an attractive therapeutic strategy, the cellular mechanisms by which PD-1 ligation results in T cell inhibition are not fully understood. PD-1 is thought to limit T cell activation by attenuating T cell receptor (TCR) signaling. It is not known whether PD-1 also acts by upregulating genes in exhausted T cells that impair their function. Here we analyzed gene expression profiles from HIV-specific CD8(+) T cells in individuals with HIV and show that PD-1 coordinately upregulates a program of genes in exhausted CD8(+) T cells from humans and mice. This program includes upregulation of basic leucine transcription factor, ATF-like (BATF), a transcription factor in the AP-1 family. Enforced expression of BATF was sufficient to impair T cell proliferation and cytokine secretion, whereas BATF knockdown reduced PD-1 inhibition. Silencing BATF in T cells from individuals with chronic viremia rescued HIV-specific T cell function. Thus, inhibitory receptors can cause T cell exhaustion by upregulating genes--such as BATF--that inhibit T cell function. Such genes may provide new therapeutic opportunities to improve T cell immunity to HIV.
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[Screening childhood behavior problems using short questionnaires II.: The Hungarian version of the SWAN-scale (Strength and Weakness of ADHD-symptoms and Normal-behavior) for screening attention deficit/hyperactivity disorder].
Psychiatr Hung
PUBLISHED: 04-06-2010
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The SWAN (Strength and Weakness of ADHD-symptoms and Normal-behavior) Questionnaire is a short instrument suitable for screening attention deficit/hyperactivity disorder. Its completion by parents or teachers requires a few minutes. Positive re-wording of attention- and activity-related behaviors and the extended 7- point rating scale anchored to average behavior make the instrument especially suitable for normal populations. Here, we report the Hungarian version of SWAN and compare its scales with relevant scales of the Child Behavior Checklist (CBCL) and the Strengths and Difficulties Questionnaire (SDQ).
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Simultaneous determination of tartaric acid and potassium in wines using a multicommuted flow system with dialysis.
Talanta
PUBLISHED: 03-12-2010
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A multicommuted flow system with the propulsion device placed before detection is proposed for the determination of tartaric acid and free potassium in table and Port wines. A dialysis unit was introduced to increase sample dilution and minimize matrix interferences. The determination of tartaric acid was based on the spectrophotometric monitorization of the complex formed by the dialyzed analyte with vanadate. Potentiometric measurement of potassium was carried out through an ion selective tubular electrode. Dynamic linear ranges of 0.500-5.00gL(-1) and 390-2000mgL(-1) were achieved for tartaric acid and potassium determinations, respectively. Detection and quantification limits of 0.1 and 0.4gL(-1) of tartaric acid were obtained, respectively. For the potentiometric determination, a detection limit of 1x10(-4)molL(-1) was achieved. The accuracy of the method was assessed by analysis of 30 wine samples by the proposed methodology and manual procedures. There were no statistical differences between the 2 sets of results, in both determinations. Relative standard deviations lower than 2.1 and 2.4% were attained by the spectrophotometric and potentiometric measurements, respectively. A determination rate of 52h(-1) was achieved.
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Sequential injection lab-on-valve system for the determination of the activity of peroxidase in vegetables.
J. Agric. Food Chem.
PUBLISHED: 01-30-2010
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Horseradish peroxidase (HRP) has been broadly used and investigated for many analytical purposes; it is an enzyme that catalyzes the reduction of hydrogen peroxide in the presence of a reducing compound. The objective of this work was to develop a methodology for the spectrophotometric determination of the activity of peroxidase in vegetable extracts using a flow method with a sequential injection lab-on-valve format. The developed system is based on the reaction between hydrogen peroxide (H(2)O(2)) and 2,2-azinobis(3-ethylbenzothiazoline-6)sulfonic acid (ABTS) catalyzed by the enzyme (HRP). The method presented a sample consumption of 15 microL per assay and a consumption of ABTS and H(2)O(2) of 24 microg and 12 microg per assay, respectively. It was also possible to monitor online the thermal inactivation of peroxidase at different temperature ranges.
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MHC class I chain-related protein A shedding in chronic HIV-1 infection is associated with profound NK cell dysfunction.
Virology
PUBLISHED: 01-12-2010
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Natural killer (NK) cells play a critical role in host defense against viral infections. However chronic HIV-1 infection is associated with an accumulation of dysfunctional NK cells, that poorly control viral replication. The underlying mechanisms for this NK cell mediated dysfunction are not understood. Certain tumors evade NK cell mediated detection by dampening NK cell activity through the downregulation of NKG2D, via the release of soluble NKG2D-ligands, resulting in a potent suppression of NK cell function. Here we show that chronic HIV-1 infection is associated with a specific defect in NKG2D-mediated NK cell activation, due to reduced expression and transcription of NKG2D. Reduced NKG2D expression was associated with elevated levels of the soluble form of the NKG2D-ligand, MICA, in patient sera, likely released by HIV+CD4+ T cells. Thus, like tumors, HIV-1 may indirectly suppress NK cell recognition of HIV-1-infected CD4+ T cells by enhancing NKG2D-ligand secretion into the serum resulting in a profound impairment of NK cell function.
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Development of a gas diffusion multicommuted flow injection system for the determination of sulfur dioxide in wines, comparing malachite green and pararosaniline chemistries.
J. Agric. Food Chem.
PUBLISHED: 03-25-2009
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A flow system based on the multicommutation concept was developed for the determination of free and total sulfur dioxide in table wines, exploiting gas diffusion separation and spectrophotometric detection. The system allowed the comparison of malachite green and pararosaniline chemistries, using the same manifold configuration. Free and total SO(2) were determined within the ranges 1.00-40.0 and 25.0-250 mg L(-1), at determination throughputs of 25 and 23 h(-1), respectively. Employing the malachite green reaction, detection limits of 0.3 and 0.8 mg L(-1) were attained for free and total SO(2), respectively. Pararosaniline chemistry provided detection limits of 0.6 mg L(-1) for free SO(2) and 0.8 mg L(-1) for total SO(2). Relative standard deviations better than 1.8 and 1.4% were obtained by the malachite green and pararosaniline reactions, respectively. With regard to the two tested chemistries, 18 wines were analyzed and the results achieved by the pararosaniline reaction compared better with those furnished by the recommended procedure.
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Sequential injection kinetic flow assay for monitoring glycerol in a sugar fermentation process by Saccharomyces cerevisiae.
Appl. Biochem. Biotechnol.
PUBLISHED: 02-17-2009
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A sequential injection system to monitor glycerol in a Saccharomyces cerevisiae fermentation process was developed. The method relies on the rate of formation of nicotinamide adenine dinucleotide in its reduced form (NADH, measured spectrophotometrically at 340 nm) from the reaction of glycerol with NAD(+) cofactor, catalysed by the enzyme glycerol dehydrogenase present in solution. This procedure enables the determination of glycerol between 0.046 and 0.46 g/l, (corresponding to yeast fermentation samples with concentrations up to 50 g/l) with good repeatability (relative standard deviation for n = 10 lower than 2.2% for three different samples) at a sampling frequency of 25/h. The detection and quantification limits using a miniaturised spectrophotometer were 0.13 and 0.44 mM, respectively. Reagent consumption was of 0.45 mumol NAD(+) and 1.8 microg enzyme per assay, and the waste production was 2.8 ml per determination. Results obtained for samples were in agreement with those obtained with a high-performance liquid chromatography method.
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Protective HLA class I alleles that restrict acute-phase CD8+ T-cell responses are associated with viral escape mutations located in highly conserved regions of human immunodeficiency virus type 1.
J. Virol.
PUBLISHED: 02-14-2009
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The control of human immunodeficiency virus type 1 (HIV-1) associated with particular HLA class I alleles suggests that some CD8(+) T-cell responses may be more effective than others at containing HIV-1. Unfortunately, substantial diversities in the breadth, magnitude, and function of these responses have impaired our ability to identify responses most critical to this control. It has been proposed that CD8 responses targeting conserved regions of the virus may be particularly effective, since the development of cytotoxic T-lymphocyte (CTL) escape mutations in these regions may significantly impair viral replication. To address this hypothesis at the population level, we derived near-full-length viral genomes from 98 chronically infected individuals and identified a total of 76 HLA class I-associated mutations across the genome, reflective of CD8 responses capable of selecting for sequence evolution. The majority of HLA-associated mutations were found in p24 Gag, Pol, and Nef. Reversion of HLA-associated mutations in the absence of the selecting HLA allele was also commonly observed, suggesting an impact of most CTL escape mutations on viral replication. Although no correlations were observed between the number or location of HLA-associated mutations and protective HLA alleles, limiting the analysis to mutations selected by acute-phase immunodominant responses revealed a strong positive correlation between mutations at conserved residues and protective HLA alleles. These data suggest that control of HIV-1 may be associated with acute-phase CD8 responses capable of selecting for viral escape mutations in highly conserved regions of the virus, supporting the inclusion of these regions in the design of an effective vaccine.
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[Immunohistochemical phenotype of breast carcinomas predicts the effectiveness of primary systemic therapy].
Magy Onkol
PUBLISHED: 02-02-2009
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The purpose of the study was to identify breast cancer subtypes by immunohistochemistry likely to respond to neoadjuvant chemotherapy and to analyze the used chemotherapy regimen and the range of response rates. Analysis of a collected database was performed. Ninety-two patients were identified in our files who received neoadjuvant chemotherapy between 1998 and 2009. We used immunohistochemical profiles (ER, PgR, HER2, Ki-67 and p53) of NCB, FNAB and surgical breast specimens to subclassify the tumors. Pathological response rates were assessed following surgical removal of tumors by using the Chevallier classification. DFS and OS was measured in 88 cases from the date of definitive surgery to the date of last follow-up or death. Pathological complete or near-complete remission (pCR = Chevallier I and II) was observed in 13 of 92 cases (14.1%). According to the preoperative characteristics of the 13 tumors achieving pCR, 9 of the cases were triple negative, one of 13 was ER-/HER2+ and three of 13 ER+/HER2+. Twenty-four of 92 patients received taxane based neoadjuvant chemotherapy, 30 of 92 anthracycline based neoadjuvant chemotherapy, 33 of 92 taxane + anthracycline regimen and 2 of 92 CMF regimen. In the taxane treated group of patients the pCR rate was 29.1%, in the anthracycline group 6.6% and in the taxane + anthracycline treated group 12.1%. Concerning DFS, significant difference was observed between the Chevallier III and IV groups (p=0.006), and less events were observed in the pCR group (not significant). pCR was associated with significantly better OS (p=0.050). It seems that even limited, routinely used immunohistochemical profiling of tumors is able to predict the likelihood of pCR to neoadjuvant chemotherapy. Patients with triple negative and HER2-positive cancers are likely to achieve pCR after neoadjuvant chemotherapy.
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Stromal matrix protein expression following preoperative systemic therapy in breast cancer.
Clin. Cancer Res.
PUBLISHED: 01-17-2009
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Stromal alterations are observed following preoperative systemic therapy in breast cancer. The aim of the present study was to analyze the qualitative and quantitative changes of representative tumor stroma proteins in the context of neoadjuvant therapy and the response of patients undergoing preoperative systemic therapy.
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Determination of ammonium in marine waters using a gas diffusion multicommuted flow injection system with in-line prevention of metal hydroxides precipitation.
J Environ Monit
PUBLISHED: 01-13-2009
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A multi-commuted flow system coupled to a gas diffusion device was developed for the spectrophotometric determination of ammonium nitrogen in sea and estuarine waters. The efficiency of complexing agents to prevent precipitation of metallic hydroxides, due to the high pH value of the carrier solution, was studied. Under the optimised conditions, no interference was observed from different expected interfering ions as well as volatile amines. The proposed method provided the determination of NH4+ in concentrations ranging from 50 to 1000 microg L(-1), with detection and quantification limits of 18 and 35 microg L(-1), respectively. A determination rate of 20 h(-1) was achieved, with good repeatability for 10 consecutive injections of sea and estuarine samples (relative standard deviations lower than 2.0%). Accuracy of the methodology was assessed through recovery assays in 10 samples and also by analysis of certified reference material.
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HLA-B57/B*5801 human immunodeficiency virus type 1 elite controllers select for rare gag variants associated with reduced viral replication capacity and strong cytotoxic T-lymphocyte [corrected] recognition.
J. Virol.
PUBLISHED: 01-01-2009
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Human immunodeficiency virus type 1 (HIV-1) elite controllers (EC) maintain viremia below the limit of commercial assay detection (<50 RNA copies/ml) in the absence of antiviral therapy, but the mechanisms of control remain unclear. HLA-B57 and the closely related allele B*5801 are particularly associated with enhanced control and recognize the same Gag(240-249) TW10 epitope. The typical escape mutation (T242N) within this epitope diminishes viral replication capacity in chronically infected persons; however, little is known about TW10 epitope sequences in residual replicating viruses in B57/B*5801 EC and the extent to which mutations within this epitope may influence steady-state viremia. Here we analyzed TW10 in a total of 50 B57/B*5801-positive subjects (23 EC and 27 viremic subjects). Autologous plasma viral sequences from both EC and viremic subjects frequently harbored the typical cytotoxic T-lymphocyte (CTL)-selected mutation T242N (15/23 sequences [65.2%] versus 23/27 sequences [85.1%], respectively; P = 0.18). However, other unique mutants were identified in HIV controllers, both within and flanking TW10, that were associated with an even greater reduction in viral replication capacity in vitro. In addition, strong CTL responses to many of these unique TW10 variants were detected by gamma interferon-specific enzyme-linked immunospot assay. These data suggest a dual mechanism for durable control of HIV replication, consisting of viral fitness loss resulting from CTL escape mutations together with strong CD8 T-cell immune responses to the arising variant epitopes.
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Designed polyelectrolyte shell on magnetite nanocore for dilution-resistant biocompatible magnetic fluids.
Langmuir
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Magnetite nanoparticles (MNPs) coated with poly(acrylic acid-co-maleic acid) polyelectrolyte (PAM) have been prepared with the aim of improving colloidal stability of core-shell nanoparticles for biomedical applications and enhancing the durability of the coating shells. FTIR-ATR measurements reveal two types of interaction of PAM with MNPs: hydrogen bonding and inner-sphere metal-carboxylate complex formation. The mechanism of the latter is ligand exchange between uncharged -OH groups of the surface and -COO(-) anionic moieties of the polyelectrolyte as revealed by adsorption and electrokinetic experiments. The aqueous dispersion of PAM@MNP particles (magnetic fluids - MFs) tolerates physiological salt concentration at composition corresponding to the plateau of the high-affinity adsorption isotherm. The plateau is reached at small amount of added PAM and at low concentration of nonadsorbed PAM, making PAM highly efficient for coating MNPs. The adsorbed PAM layer is not desorbed during dilution. The performance of the PAM shell is superior to that of poly(acrylic acid) (PAA), often used in biocompatible MFs. This is explained by the different adsorption mechanisms; metal-carboxylate cannot form in the case of PAA. Molecular-level understanding of the protective shell formation on MNPs presented here improves fundamentally the colloidal techniques used in core-shell nanoparticle production for nanotechnology applications.
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Review on recent applications of the liquid waveguide capillary cell in flow based analysis techniques to enhance the sensitivity of spectroscopic detection methods.
Anal. Chim. Acta
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Incorporation of long path length liquid waveguide capillary cell (LWCC or LCW) into spectrometric detection systems can increase the sensitivity of these by orders of magnitude (up to 500 times), and consequently can reduce the detection limits. The combination of the long path length spectrophotometry with flow methodologies can provide analytical solutions for various challenges in the field of environmental, biochemical and food chemistry. In this present work, the analytical applications of the long capillary cells are summarised and critically discussed. A historical overview of the cell development is given; applications in different areas are presented and grouped by analyte type. Major improvements achieved based on the use of the LWCC in the analytical characteristics (like sensitivity and detection limit) are emphasised while some of the limitations are also discussed.
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TCR clonotypes modulate the protective effect of HLA class I molecules in HIV-1 infection.
Nat. Immunol.
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The human leukocyte antigens HLA-B27 and HLA-B57 are associated with protection against progression of disease that results from infection with human immunodeficiency virus type 1 (HIV-1), yet most people with alleles encoding HLA-B27 and HLA-B57 are unable to control HIV-1. Here we found that HLA-B27-restricted CD8(+) T cells in people able to control infection with HIV-1 (controllers) and those who progress to disease after infection with HIV-1 (progressors) differed in their ability to inhibit viral replication through targeting of the immunodominant epitope of group-associated antigen (Gag) of HIV-1. This was associated with distinct T cell antigen receptor (TCR) clonotypes, characterized by superior control of HIV-1 replication in vitro, greater cross-reactivity to epitope variants and enhanced loading and delivery of perforin. We also observed clonotype-specific differences in antiviral efficacy for an immunodominant HLA-B57-restricted response in controllers and progressors. Thus, the efficacy of such so-called protective alleles is modulated by specific TCR clonotypes selected during natural infection, which provides a functional explanation for divergent HIV-1 outcomes.
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Frequent and strong antibody-mediated natural killer cell activation in response to HIV-1 Env in individuals with chronic HIV-1 infection.
J. Virol.
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Natural killer (NK) cells play a critical role in the control of HIV-1 infection, and NK cells that respond to HIV-1 peptides have been recently described. However, the mechanisms by which NK cells recognize HIV-1 antigens are not fully understood. We investigated NK cell activation in response to HIV-1 peptides during early and chronic HIV-1 clade B infection using a whole-blood assay and multiparameter flow cytometry. Antibody-mediated NK cell activation in response to HIV-1 peptides was not detected in HIV-1-uninfected individuals. In contrast, 79% of individuals with chronic infection and 22% of individuals with early infection had detectable gamma interferon (IFN-?) NK cell responses to HIV-1 antigens (P < 0.00001). IFN-?- and tumor necrosis factor alpha (TNF-?)-producing NK cells most frequently targeted Env gp120 (median of 4% and range of 0 to 31% of all NK cells). NK cells rarely targeted other HIV-1 proteins such as Gag, Pol, and Nef. Antibody-mediated NK cell responses to peptides mapped predominantly to Env protein, required the presence of plasma or plasma IgG, and resulted in lower CD16 expression on NK cells, suggesting an antibody-mediated activation of NK cells. Further studies are needed to assess the consequences of these antibody-mediated NK cell responses for HIV-1 disease progression and vaccine-induced protection from infection.
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Driving forces of conformational changes in single-layer graphene oxide.
ACS Nano
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The extensive oxygen-group functionality of single-layer graphene oxide proffers useful anchor sites for chemical functionalization in the controlled formation of graphene architecture and composites. However, the physicochemical environment of graphene oxide and its single-atom thickness facilitate its ability to undergo conformational changes due to responses to its environment, whether pH, salinity, or temperature. Here, we report experimental and molecular simulations confirming the conformational changes of single-layer graphene oxide sheets from the wet or dry state. MD, PM6, and ab initio simulations of dry SLG and dry and wetted SLGO and electron microscopy imaging show marked differences in the properties of the materials that can explain variations in previously observed results for the pH dependent behavior of SLGO and electrical conductivity of chemically modified graphene-polymer composites. Understanding the physicochemical responses of graphene and graphene oxide architecture and performing selected chemistry will ultimately facilitate greater tunability of their performance.
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Preserved function of regulatory T cells in chronic HIV-1 infection despite decreased numbers in blood and tissue.
J. Infect. Dis.
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Regulatory T cells (Tregs) are potent immune modulators, but their role in human immunodeficiency virus type 1 (HIV-1) pathogenesis remains poorly understood. We performed a detailed analysis of the frequency and function of Tregs in a large cohort of HIV-1-infected individuals and HIV-1 negative controls. While HIV "elite controllers" and uninfected individuals had similar Treg numbers and frequencies, the absolute numbers of Tregs declined in blood and gut-associated lymphoid tissue in patients with chronic progressive HIV-1 infection. Despite quantitative changes in Tregs, HIV-1 infection was not associated with an impairment of ex vivo suppressive function of flow-sorted Tregs in both HIV controllers and untreated chronic progressors.
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Enhanced stability of polyacrylate-coated magnetite nanoparticles in biorelevant media.
Colloids Surf B Biointerfaces
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Magnetite nanoparticles (MNPs) were prepared by alkaline hydrolysis of Fe(II) and Fe(III) chlorides. Adsorption of polyacrylic acid (PAA) on MNPs was measured at pH=6.5±0.3 and I=0.01 M (NaCl) to find the optimal PAA amount for MNP stabilization under physiological conditions. We detected an H-bond formation between magnetite surface groups and PAA by ATR-FTIR measurements, but bonds of metal ion-carboxylate complexes, generally cited in literature, were not identified at the given pH and ionic strength. The dependence of the electrokinetic potential and the aggregation state on the amount of added PAA at various pHs was measured by electrophoretic mobility and dynamic light-scattering methods. The electrokinetic potential of the naked MNPs was low at near physiological pH, but PAA adsorption overcharged the particles. Highly negatively charged, well-stabilized carboxylated MNPs formed via adsorption of PAA in an amount of approximately ten times of that necessary to compensate the original positive charge of the magnetite. Coagulation kinetics experiments revealed gradual enhancement of salt tolerance at physiological pH from ~0.001 M at no added PAA up to ~0.5 M at 1.12 mmol/g PAA. The PAA-coated MNPs exert no substantial effect on the proliferation of malignant (HeLa) or non-cancerous fibroblast cells (MRC-5) as determined by means of MTT assays.
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In developing our video relationships, we compare around 5 million PubMed articles to our library of over 4,500 methods videos. In some cases the language used in the PubMed abstracts makes matching that content to a JoVE video difficult. In other cases, there happens not to be any content in our video library that is relevant to the topic of a given abstract. In these cases, our algorithms are trying their best to display videos with relevant content, which can sometimes result in matched videos with only a slight relation.