1,721,142 research outputs found
Chemotaxis and activation of human peripheral blood eosinophils induced by pollen-associated lipid mediators
No full textBackground: Eosinophil accumulation at sites of allergic inflammation is largely regulated by chemokines and lipid mediators released by a variety of cells of the local microenvironment. Recent studies have shown that pollen grains, apart from their function as allergen carriers, are a rich exogenous source of eicosanoid-like lipid mediators that are rapidly released on contact with the aqueous phase and thus may contribute to the generation of local inflammatory responses. Objective: Here we analyze the biological activity of pollen-associated lipid mediators (PALMs) on peripheral human blood eosinophils. Methods: Human eosinophils were coincubated with pollen grains and analyzed by electron microscopy. The lipid mediator composition of aqueous pollen extracts (APEs) was analyzed by HPLC. Human eosinophils were exposed to APEs or lipid fractions from pollen. Effects on eosinophils were tested by transwell migration and surface expression of CD11b. Results: In vitro experiments showed adhesion of eosinophils to Phleum pratense pollen. In chemotaxis assays eosinophils displayed significant directed migration to APEs. HPLC analysis of APEs from Phleum pratense and Betula alba pollen demonstrated the occurrence of linoleic and alpha-linolenic acid as well as their monohydroxylated derivatives. Moreover, total lipid extracts from pollen and RP-HPLC fractions containing monohydroxylated derivatives of linoleic and alpha-linolenic acid induced similar migratory responses, although to a lesser degree than APEs. In addition, APEs and lipid extracts induced up-regulation of CD11b surface expression and secretion of eosinophil cationic protein. APE-induced chemotaxis was blocked by the leukotriene B-4 receptor antagonist LY293111, suggesting that PALMs may serve as ligands for LTB4 receptors. Conclusion: Pollen grains release lipid mediators that recruit and activate eosinophils in vitro. Similar mechanisms may be effective under natural exposure conditions, in which PALMs may play a role in the recruitment of eosinophils to the site of allergic inflammation
Direct and indirect activation of human eosinophil granulocytes by airborne particulate matter
No full textWeil in den letzten Jahren in mehreren wissenschaftlichen Studien ein direkter Zusammenhang zwischen verkehrsbedingten Feinstaubimmissionen und Erkrankungen aus dem atopischen Formenkreis aufgezeigt wurde, sollte im Rahmen dieser Arbeit die direkte und indirekte Interaktion zwischen humanen Eosinophilen und Rußpartikeln untersucht werden. Alle untersuchten Partikelarten (Diesel Standard SRM 1650a, Printex G und Printex 90) konnten in eosinophilen Granulozyten eine vermehrte ECP-Freisetzung induzieren. Darüber hinaus wurde nachgewiesen, dass Überstände Partikel-stimulierter (0,5, 5, 50 µg/ml/106Zellen, 48 h) humaner Keratinozyten über eine dosisabhängige signifikant erhöhte GM-CSF Freisetzung eosinophile Granulozyten zur Chemotaxis und ECP-Freisetzung anregten.In recent years several studies have been published, which showed a direct relationship between traffic-related airborne particulate matter and atopic diseases. Therefore we investigated the direct and indirect crosstalk between human eosinophils and soot particles in this dissertation. All used particles (Diesel standard SRM 1650a, Printex G und Printex 90) induced an enhanced ECP-release in eosinophils granulocytes. Moreover, in eosinophil granulocytes, supernatants of particle-stimulated human keratinocytes (0.5, 5, 50µg/ml/106cells, 48 h) provoked GM-CSF-related significant chemotaxis and ECP-release in a dose dependent manner
Effect of pesticides in food on in vivo and in vitro reactivity of specific sensitized allergics
Full text linkIn dieser Arbeit sollte untersucht werden, ob durch Zusatz von Pestizid die Allergenität von Apfel verändert wird. Dazu wurden Pricktestungen und Histaminfreisetzungstests mit Apfelextrakt, Pestiziden (Chlorpropham, Thiram, Iprodion) bei 22 Apfelallergikern, 20 Atopikern ohne Apfelallergie und 20 Nichtatopikern durchgeführt. Die Pestizide allein zeigten weder in der Pricktestung noch im Histaminfreisetzungstest positive Reaktionen. Bei einigen pestizidversetzten Apfelextrakten (mit Thiram und Iprodion) zeigte sich ein signifikanter Unterschied der Pricktestreaktion im Vergleich zur Pricktestung mit Apfel allein, in jedem Fall im Sinne einer Abschwächung der Pricktestreaktion. Im Histaminfreisetzungstest zeigten sich bei der Simultanstimulation mit Apfel und Chlorporpham sowie auch bei Apfel und Thiram signifikante Unterschiede gegenüber der Histaminfreisetzung mit Apfel allein, jeweils im Sinne einer Abschwächung der Histaminfreisetzung.Aim of this study was to investigate if the addition of pesticide changes the allergic reactivity of apple. Therefore, apple extract and/or pesticides (chlorpropham, thiram, iprodione) were tested by skin prick test and by histamine release on 22 patients allergic to apple, 20 atopic patients without apple allergy and 20 not atopic persons. Pesticides alone did not show a positive reaction, neither in the skin prick test, nor in the histamine release. Some pesticide added apple extracts (with thiram and iprodione) showed a significant reduction in prick test reaction compared to apple alone. In histamine release, in some simultaneous stimulation with apple and pesticide (chlorpropham and thiram) a significant decrease in histamine release compared to stimulation with apple alone was shown
Investigation of the impact of relative humidity on allergen release from pollen
Full text linkPollen von Hasel, Erle, Birke, Honiggras und Beifuß wurden im Wirbelschichtreaktor gegenüber unterschiedlichen relativen Luftfeuchten (0 bis 80 % rF) und SO2-Konzentrationen (0,0076 bis 5 ppm SO2) für 9 Stunden exponiert. Für Honiggras- und Beifußpollen konnte eine signifikante zeitabhängige negative Korrelation zwischen relativer Luftfeuchte und der extrahierbaren Proteinmenge festgestellt werden. Dieser Effekt wurde durch SO2 konzentrations- und zeitabhängig reduziert. Die Ergebnisse sind durch hydrodynamische Regelprozesse zu erklären und deuten auf einen Einfluß von Umweltfaktoren auf atmosphärische Allergenkonzentrationen.In simulating natural air conditions pollen from hazel, alder, birch, meadow velvet and mugwort were exposed to synthetic air with different relative humidities (from 0 to 80 % rH) and concentrations of sulfur dioxide (from 0.0076 to 5 ppm SO2) for up to 9 hours in a fluidized bed reactor. A significant time dependant negative correlation between rH and protein content in the pollen extracts could be shown for meadow velvet and mugwort pollen. The effect was reduced by SO2 in a concentration and time dependant manner. This finding might be due to hydrodynamic mechanisms and sheds new light on the influence of environmental factors on atmospheric allergen concentrations
Fractional sizes detection of allergen, allergen charged particles and pollen in ambient air
No full textIn der vorliegenden Arbeit wurden in der Pollenflugsaison mit Hilfe eines ChemVol® high Volume Cascade Impaktors Partikel in der Außenluft gesammelt und nach ihrer aerodynamischen Größe aufgetrennt. Der Allergengehalt der einzelnen Partikelfraktionen wurde mittels eines Enzyme-linked Immunosorbent Assays bestimmt und mit den in einer Burkard-Pollenfalle gemessenen Pollenflugdaten verglichen. Ziel der Untersuchung war es, die allergenhaltigen Partikel der Umluft zu klassifizieren und das Verhältnis zwischen Pollenbelastung und tatsächlicher Allergenbelastung genauer zu beleuchten.In the present work particles in ambient air were collected during the pollen season using a ChemVol high volume cascade impactor and separated according to their aerodynamic size. The allergen content of the individual particle fractions was measured by Enzyme-linked Immunosorbent Assays and compared with a Burkard pollen trap measured data. The aim of this study was to classify the allergen-containing particles of ambient air and describe the relationship between pollen exposure and real allergen exposure
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
- …
