985 resultados para Ionic activity


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BACKGROUND: The correlation between noninvasive markers with endoscopic activity according to the modified Baron Index in patients with ulcerative colitis (UC) is unknown. We aimed to evaluate the correlation between endoscopic activity and fecal calprotectin (FC), C-reactive protein (CRP), hemoglobin, platelets, blood leukocytes, and the Lichtiger Index (clinical score). METHODS: UC patients undergoing complete colonoscopy were prospectively enrolled and scored clinically and endoscopically. Samples from feces and blood were analyzed in UC patients and controls. RESULTS: We enrolled 228 UC patients and 52 healthy controls. Endoscopic disease activity correlated best with FC (Spearman's rank correlation coefficient r = 0.821), followed by the Lichtiger Index (r = 0.682), CRP (r = 0.556), platelets (r = 0.488), blood leukocytes (r = 0.401), and hemoglobin (r = -0.388). FC was the only marker that could discriminate between different grades of endoscopic activity (grade 0, 16 [10-30] μg/g; grade 1, 35 [25-48] μg/g; grade 2, 102 [44-159] μg/g; grade 3, 235 [176-319] μg/g; grade 4, 611 [406-868] μg/g; P < 0.001 for discriminating the different grades). FC with a cutoff of 57 μg/g had a sensitivity of 91% and a specificity of 90% to detect endoscopically active disease (modified Baron Index ≥ 2). CONCLUSIONS: FC correlated better with endoscopic disease activity than clinical activity, CRP, platelets, hemoglobin, and blood leukocytes. The strong correlation with endoscopic disease activity suggests that FC represents a useful biomarker for noninvasive monitoring of disease activity in UC patients.

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MAGE-encoded antigens, which are expressed by tumors of many histological types but not in normal tissues, are suitable candidates for vaccine-based immunotherapy of cancers. Thus far, however, T-cell responses to MAGE antigens have been detected only occasionally in cancer patients. In contrast, by using HLA/peptide fluorescent tetramers, we have observed recently that CD8(+) T cells specific for peptide MAGE-A10(254-262) can be detected frequently in peptide-stimulated peripheral blood mononuclear cells from HLA-A2-expressing melanoma patients and healthy donors. On the basis of these results, antitumoral vaccination trials using peptide MAGE-A10(254-262) have been implemented recently. In the present study, we have characterized MAGE-A10(254-262)-specific CD8(+) T cells in polyclonal cultures and at the clonal level. The results indicate that the repertoire of MAGE-A10(254-262)-specific CD8(+) T cells is diverse both in terms of clonal composition, efficiency of peptide recognition, and tumor-specific lytic activity. Importantly, only CD8(+) T cells able to recognize the antigenic peptide with high efficiency are able to lyse MAGE-A10-expressing tumor cells. Under defined experimental conditions, the tetramer staining intensity exhibited by MAGE-A10(254-262)-specific CD8(+) T cells correlates with efficiency of peptide recognition so that "high" and "low" avidity cells can be separated by FACS. Altogether, the data reported here provide evidence for functional diversity of MAGE-A10(254-262)-specific T cells and will be instrumental for the monitoring of peptide MAGE-A10(254-262)-based clinical trials.

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NORTH SEA STUDY OCCASIONAL PAPER No. 109

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NORTH SEA STUDY OCCASIONAL PAPER No. 113

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NORTH SEA STUDY OCCASIONAL PAPER No. 120

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NORTH SEA STUDY OCCASIONAL PAPER No. 122

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NORTH SEA STUDY OCCASIONAL PAPER No. 119

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NORTH SEA STUDY OCCASIONAL PAPER No. 114

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BACKGROUND: School-based intervention studies promoting a healthy lifestyle have shown favorable immediate health effects. However, there is a striking paucity on long-term follow-ups. The aim of this study was therefore to assess the 3 yr-follow-up of a cluster-randomized controlled school-based physical activity program over nine month with beneficial immediate effects on body fat, aerobic fitness and physical activity. METHODS AND FINDINGS: Initially, 28 classes from 15 elementary schools in Switzerland were grouped into an intervention (16 classes from 9 schools, n = 297 children) and a control arm (12 classes from 6 schools, n = 205 children) after stratification for grade (1st and 5th graders). Three years after the end of the multi-component physical activity program of nine months including daily physical education (i.e. two additional lessons per week on top of three regular lessons), short physical activity breaks during academic lessons, and daily physical activity homework, 289 (58%) participated in the follow-up. Primary outcome measures included body fat (sum of four skinfolds), aerobic fitness (shuttle run test), physical activity (accelerometry), and quality of life (questionnaires). After adjustment for grade, gender, baseline value and clustering within classes, children in the intervention arm compared with controls had a significantly higher average level of aerobic fitness at follow-up (0.373 z-score units [95%-CI: 0.157 to 0.59, p = 0.001] corresponding to a shift from the 50th to the 65th percentile between baseline and follow-up), while the immediate beneficial effects on the other primary outcomes were not sustained. CONCLUSIONS: Apart from aerobic fitness, beneficial effects seen after one year were not maintained when the intervention was stopped. A continuous intervention seems necessary to maintain overall beneficial health effects as reached at the end of the intervention. TRIAL REGISTRATION: ControlledTrials.com ISRCTN15360785.

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Haemolymph, heads, salivary glands, crops, midguts, hindguts, and Malpighian tubules from Rhodnius prolixus and Triatoma infestans were extracted in phosphate or Tris buffer saline with calcium, and tested for agglutination and lytic activities by microtitration against both vertebrateerythrocytes and cultured epimatigote forms of Trypanosoma rangeli. Haemagglutination activity against rabbit erythrocytes was found in the crop, midgut and hindgut extracts of T. infestans but only in the haemolymph of R. prolixus. Higher titres of parasite agglutinins were found in R. prolixus haemolymph than T. infestans, whilst the converse occurred for the tissue extracts. In addition, the extracts of T. infestans salivary glands, but not those of R. prolixus, showed a trypanolytic activity that was heat-inactivated and was not abolished by pre-incubation with any of the sugars or glycoproteins tested. T. infestans, which is refractory to infection by T. rangeli, thus appears to contain a much wider distribution of agglutinating and trypanolytic factors in its tissues than the more susceptible species, R. prolixus

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Abstract Long term contact with pathogens induces an adaptive immune response, which is mainly mediated by T and B cells. Antigen-induced activation of T and B cells is an important event, since it facilitates the transition of harmless, low proliferative lymphocytes into powerful and fast expanding cells, which can, if deregulated, be extremely harmful and dangerous for the human body. One of the most important events during lymphocyte activation is the induction of NF-xB activity, a transcription factor that controls not only cytokine secretion, but also lymphocyte proliferation and survival. Recent discoveries identified the CBM complex as the central regulator of NF-xB activity in lymphocytes. The CBM complex consists of the three proteins Carma1, Bcl10 and Malt1, in which Carma1 serves as recruitment platform of the complex and Bcl10 as an adaptor to recruit Malt1 to this platform. But exactly how Malt1 activates NF-x6 is still poorly understood. We discovered that Malt1 is a protease, which cleaves its interaction partner Bcl10 upon T and B cell stimulation. We mapped the Bcl10 cleavage site by single point mutations as well as by a proteomics approach, and used this knowledge to design a fluorogenic Malt1 reporter peptide. With this tool were we able to the first time demonstrate proteolytic activity of Malt1 in vitro, using recombinant Malt1, and in stimulated T cells. Based on similarities to a metacaspase, we designed a Malt1inhibitor, which allowed unto investigate the role of Malt1 activity in T cells. Malt1-inhibited T cells showed a clear defect in NF-xB activity, resulting in impaired IL-2 cytokine secretion levels. We also found a new unexpected role for Bcl10; the blockade of Bcl10 cleavage resulted in a strongly impaired capability of stimulated T cells to adhere to the extracellular matrix protein fibronectin. Because of the central position of the C8M complex, it is not surprising that different lymphomas show abnormal expressions of Carma1, Bcl10 and Malt1. We investigated the role of Malt1 proteolytic activity in the most aggressive subtype of diffuse large B cell lymphomas called ABC, which was described to depend on the expression of Carmal, and frequently carries oncogenic Carmal mutations. We found constitutive high Malt1 activity in all tested ABC cell lines visualized by detection of cleavage products of Malt1 substrates. With the use of the Malt1-inhibitor, we could demonstrate that Malt-inhibition in those cells had two effects. First, the tumor cell proliferation was decreased, most likely because of lower autocrine stimulation by cytokines. Second, we could sensitize the ABC cells towards cell death, which is most likely caused by reduced expression of prosurvival NF-xB target gens. Taken together, we identified Malt1 as a protease in T and B cells, demonstrated its importance for NF-xB signaling and its deregulation in a subtype of diffuse large B cell lymphoma. This could allow the development of a new generation of immunomodulatory and anti-cancer drugs. Résumé Un contact prolongé avec des pathogènes provoque une réponse immunitaire adaptative qui dépend principalement des cellules T et 8. L'activation des lymphocytes T et B, suite à la reconnaissance d'un antigène, est un événement important puisqu'il facilite la transition pour ces cellules d'un état de prolifération limitée et inoffensive à une prolifération soutenue et rapide. Lorsque ce mécanisme est déréglé ìl peut devenir extrêmement nuisible et dangereux pour le corps humain. Un des événement les plus importants lors de l'activation des lymphocytes est l'induction du facteur de transcription NFxB, qui organise la sécrétion de cytokines ainsi que la prolifération et la survie des lymphocytes. Le complexe CBM, composé des trois protéines Carmai, Bc110 et Malt1, a été récemment identifié comme un régulateur central de l'activité de NF-x8 dans les lymphocytes. Carma1 sert de plateforme de recrutement pour ce complexe alors que Bc110 permet d'amener Malt1 dans cette plateforme. Cependant, le rôle exact de Malt1 dans l'activation de NF-tcB reste encore mal compris. Nous avons découvert que Malt1 est une protéase qui clive son partenaire d'interaction BcI10 après stimulation des cellules T et B. Nous avons identifié le site de clivage de BcI10 par une série de mutations ponctuelles ainsi que par une approche protéomique, ce qui nous a permis de fabriquer un peptide reporteur fluorogénique pour mesurer l'activité de Malt1. Grâce à cet outil, nous avons démontré pour la première fois l'activité protéolytique de Malt1 in vitro à l'aide de protéines Malt1 recombinantes ainsi que dans des cellules T stimulées. La ressemblance de Malt1 avec une métacaspase nous a permis de synthétiser un inhibiteur de Malt1 et d'étudier ainsi le rôle de l'activité de Malt1 dans les cellules T. L'inhibition de Malt1 dans les cellules T a révélé un net défaut de l'activité de NF-x8, ayant pour effet une sécrétion réduite de la cytokine IL-2. Nous avons également découvert un rôle inattendu pour Bcl10: en effet, bloquer le clivage de Bcl10 diminue fortement la capacité d'adhésion des cellules T stimulées à la protéine fïbronectine, un composant de la matrice extracellulaire. En raison de la position centrale du complexe CBM, il n'est pas étonnant que le niveau d'expression de Carmai, Bcl10 et Malt1 soit anormal dans plusieurs types de lymphomes. Nous avons examiné le rôle de l'activité protéolytique de Malt1 dans le sous-type le plus agressif des lymphomes B diffus à grandes cellules, appelé sous-type ABC. Ce sous-type de lymphomes dépend de l'expression de Carmai et présente souvent des mutations oncogéniques de Carma1. Nous avons démontré que l'activité de Malt1 était constitutivement élevée dans toutes les lignées cellulaires de type ABC testées, en mettant en évidence la présence de produits de clivage de différents substrats de Malt1. Enfin, l'utilisation de l'inhibiteur de Malt1 nous a permis de démontrer que l'inhibition de Malt1 avait deux effets. Premièrement, une diminution de la prolifération des cellules tumorales, probablement dûe à leur stimulation autocrine par des cytokines fortement réduite. Deuxièmement, une sensibilisation des cellules de type ABC à ia mort cellulaire, vraisemblablement causée par l'expression diminuée de gènes de survie dépendants de NF-tcB. En résumé, nous avons identifié Malt1 comme une protéase dans les cellules T et B, nous avons mis en évidence son importance pour l'activation de NF-xB ainsi que les conséquences du dérèglement de l'activité de Malt1 dans un sous-type de lymphome B diffus à larges cellules. Notre étude ouvre ainsi la voie au développement d'une nouvelle génération de médicaments immunomodulateurs et anti-cancéreux.

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Helicobacter-induced gastritis is considered nowadays an epidemic, the prevalence of which is one of the highest world-wide (70%), with as much as 40% of the population in industrialized countries. Helicobacter pylori (H. pylori) antigens (Ag) capable to elicit a protective immune response in animal models have been identified, but these antigens have not been shown to be strongly immunogenic when administered to humans. Due to their stability in the gastric environment and avidity, passive administration of secretory immunoglobulin A (SIgA) antibodies (Ab) targeting protective Ag might be particularly relevant as a substitute or complement to current therapies. To this aim, we have designed expression vectors to convert a scFv polypeptide specific for H. pylori urease subunit A into human IgG, polymeric IgA (IgAp/d) and SIgA. Purified proteins show proper binding characteristics toward both the native and denatured forms of H. pylori urease. The direct comparison between different isotype and molecular forms, but of unique specificity, demonstrates that SIgA and IgAp/d are more efficient in blocking free and H. pylori-associated urease than IgG and scFv. We conclude that the expression system reported herein will represent a valuable tool to produce human SIgA Ab of multiple specificities against H. pylori antigens involved in colonization and persistence.