Podcasts about rlot

Thomas og Christian har fremdeles sommerferie, men avbryter ferien nok en gang for å spille inn Flight 024. Thomas stikker midt i dagens episode for å rekke et fly til Berlin, mens Christian har byttet ut fly med småbåter. Denne gang snakker flyr vi innom både Warszawa, Seattle, Brussel og ikke minst Farnborough.Christian gjør noe han ikke kan! Siden Thomas har dratt på kjærlighetsferie til Berlin, må Christian redigere og distribuere ukens sending… :-0Vi sender en ekstra takk til alle som har støttet oss via Patreon. Klikk her for å støtte oss via Patreon!AktueltBrussels Airlines får ansvar for Eurowings' low-cost long-haul-flygningerBoeing NMA blir ikke lansert i årLOT interessert i å kjøpe Croatia AirlinesJetBlue vurderer flygninger til EuropaUkens hovedtema – FarnboroughOm FarnboroughFlightGlobals «Farnborough Air Show Order Tracker»Noen av bestillingene vi snakket omDHL kjøper 14 Boeing 777FJet Airways kjøper 75 737MAXTarom kjøper 5 Boeing 737MAX-8United kjøper ytterligere fire Boeing 787-9Nytt flyselskap på Taiwan – StarLux – skriver intensjonsavtale om å kjøpe 17 A350StarLux Airbus A350 Flypodden anbefalerSjekk ut FlightGlobals dekning av Farnborough Air Show!Anbefaler særlig deres Flight Daily News – helt gratis! See acast.com/privacy for privacy and opt-out information.

Methods based on nanotechnologies play a growing role in biomedical research. Quantum dots (QDs) are a group of engineered fluorescent nanoparticles suited for advanced imaging applications. The substitution of the particle’s surface with defined molecular structures could enable the adoption as targeted contrast agents or therapeutic devices for a variety of clinical approaches. However, important aspects such as the basic surfacedependent behavior of non-targeted QDs in the organism and arising health effects upon systemic administration remain incompletely understood. Acute inflammatory effects for instance are often initiated on the microcirculatory level and are probably relevant for cardiovascular pathologies observed in epidemiologic and experimental studies of certain nanoparticles. Most in vitro studies show that the surface structures of QDs and other nanoparticles seem to be predominantly accountable for different cytotoxic effects and a variable potential to liberate proinflammatory cytokines. Currently, no systematic in vivo studies have addressed surface-dependent interactions of QDs on the level of the microcirculation and assessed the resulting impact on biokinetics as well as on proinflammatory parameters. Thus, this thesis aimed to i) analyze the incidence of QDsurface- dependent acute microvascular interactions and their influence on key biokinetic parameters and ii) investigate acute immunomodulatory effects on the multistep process of leukocyte recruitment in vivo. For this, three types of commercially available QDs with different surface modifications: carboxyl-QDs, amine- and polyethylene glycol-QDs (amine-QDs) and polyethylene glycol-QDs (PEG-QDs) were used. The physicochemical characterization was done by dynamic light scattering (DLS) analysis and microscale thermophoresis. In a first set of experiments, circulating half-lives, tissue distribution in different organs, and hepatic as well as renal clearance were measured. Ex vivo analysis of QD tissue distribution was performed on selected tissue samples via transmission electron microscopy (TEM) and two-photon microscopy. By combining reflected-light oblique transillumination (RLOT) and fluorescence in vivo microscopy of the murine M. cremaster, interactions of QDs with components of the microcirculation as well as leukocyte migration parameters were visualized and quantified. The extreme short circulating half-life of anionic carboxyl-QDs was related to pronounced clearance by the mononuclear phagocyte system. Beyond this, further investigations showed, for the first time, that the continuous capillary endothelium of skeletal and heart muscle tissue has the capacity to directly extract carboxyl-QDs from the circulation by means of caveolaemediated endocytosis. Carboxyl-QDs were also taken up by perivascular macrophages in the surgically exposed but not in the native M. cremaster and led to a significant increase of adherent and (subsequently) transmigrated leukocytes in this model. Further experiments provided evidence for a probable involvement of mast cells in the intercellular adhesion molecule-1 (ICAM-1)- and endothelial (E)-selectinmediated modulation of leukocyte recruitment. This process is most likely initiated by the endocytosis of carboxyl-QDs through activated perivascular macrophages. The primary activation of tissue-resident perivascular macrophages seems to be the consequence of tissue damage related to the surgical preparation of the cremaster muscle. This is supposedly a prerequisite for the endocytosis of carboxyl-QDs whereupon endothelial and mast cells seem to be secondarily activated in a paracrine fashion that then leads to an increase in leukocyte recruitment.

The emigration of leukocytes from the circulation is a critical step during immune surveillance and inflammatory reactions that is governed by a coordinated interplay involving a spectrum of adhesion and signal molecules. While a great deal has been learned about the early steps of leukocyte recruitment, i.e. rolling and adhesion, little is known about the subsequent steps, transendothelial and interstitial migration when leukocytes migrate across the endothelial layer lining the blood vessel and move to the sites of inflammation. In particular, it is not fully understood which endothelial receptors are responsible for extravasation of leukocytes into the perivascular space. Moreover, the mechanisms of interstitial migration of leukocytes during inflammation remain to be clarified in vivo. In the first part of the study, we analyzed the role of ESAM for leukocyte migration in vivo. ESAM is a novel adhesion receptor which is specifically expressed at endothelial tight junctions and on platelets. Using RLOT intravital microscopy of the murine cremaster muscle, we have shown that IL-1β-induced leukocyte transmigration was reduced by about 50% in ESAM-deficient mice without affecting leukocyte rolling and adhesion. In summary, ESAM at endothelial tight junctions participates in the migration of neutrophils through the vessel wall. In the second part of the study, we investigated the role of two other recently discovered receptors, CD99 and CD99L2, for leukocyte migration. Similar to ESAM, these receptors are expressed at endothelial cell contacts but did not belong to any of the known protein families. We demonstrate that CD99 and CD99L2 mediate transendothelial migration of neutrophils in vivo without any effect on leukocyte rolling and adhesion. Finally, we show that the inhibitory effect of anti-CD99 and CD99L2 antibodies on cytokine-induced leukocyte transmigration in cremasteric venules is amplified in PECAM-1-/- mice. This fact suggests that a functional relationship between PECAM-1 and CD99/ CD99L2 might exist in mediating leukocyte transmigration. Taken together, our study provides the first evidence for a role of CD99 and CD99L2 in the process of leukocyte transendothelial migration in vivo. In the third part of the study, we established a novel approach allowing the visualization and analysis of directional leukocyte interstitial migration in vivo. Our technique combines RLOT and multicolor fluorescence microscopy with microinjection for local application of chemoattractants. In the mouse cremaster muscle, we show that microinjection of chemoattractants (MIP-1α and PAF) induced directional leukocyte polarization and migration. Combination of RLOT microscopy with fluorescence microscopy allowed simultaneous visualization and analysis of migratory behavior of different leukocyte subsets upon chemotactic stimulation. Moreover, this approach enabled an imaging of subcellular events such as mitochondria redistribution in single polarized interstitially migrating leukocytes in vivo. This technique opens new avenues for investigations of the mechanisms of interstitial migration of leukocytes as well as the observation of morphological changes and subcellular events in different leukocyte subsets during their interstitial migration in vivo.

Directional migration of transmigrated leukocytes to the site of injury is a central event in the inflammatory response. Here, we present an in vivo chemotaxis assay enabling the visualization and quantitative analysis of subtype-specific directional motility and polarization of leukocytes in their natural 3D microenvironment. Our technique comprises the combination of i) semi-automated in situ microinjection of chemoattractants or bacteria as local chemotactic stimulus, ii) in vivo near-infrared reflected-light oblique transillumination (RLOT) microscopy for the visualization of leukocyte motility and morphology, and iii) in vivo fluorescence microscopy for the visualization of different leukocyte subpopulations or fluorescence-labeled bacteria. Leukocyte motility parameters are quantified off-line in digitized video sequences using computer-assisted single cell tracking. Here, we show that perivenular microinjection of chemoattractants [macrophage inflammatory protein-1alpha (MIP-1alpha/Ccl3), platelet-activating factor (PAF)] or E. coli into the murine cremaster muscle induces target-oriented intravascular adhesion and transmigration as well as polarization and directional interstitial migration of leukocytes towards the locally administered stimuli. Moreover, we describe a crucial role of Rho kinase for the regulation of directional motility and polarization of transmigrated leukocytes in vivo. Finally, combining in vivo RLOT and fluorescence microscopy in Cx3CR1(gfp/gfp) mice (mice exhibiting green fluorescent protein-labeled monocytes), we are able to demonstrate differences in the migratory behavior of monocytes and neutrophils.Taken together, we propose a novel approach for investigating the mechanisms and spatiotemporal dynamics of subtype-specific motility and polarization of leukocytes during their directional interstitial migration in vivo.