Biomedical subjects

Winfried Möller

Publications and source records attributed to Winfried Möller.

10 recordsLinked to original sources

PubMed2006

Motion and twisting of magnetic particles ingested by alveolar macrophages in the human lung: effect of smoking and disease.

BACKGROUND: Magnetic microparticles being ingested by alveolar macrophages can be used as a monitor for intracellular phagosome motions and cytoskeletal mechanical properties. These studies can be performed in the human lung after voluntary inhalation. The influence of cigarette smoking and lung diseases on cytoskeleton dependent functions was studied. METHODS: Spherical 1.3 microm diameter ferrimagnetic iron oxide particles were inhaled by 17 healthy volunteers (40-65 years), 15 patients with sarcoidosis (SAR), 12 patients with idiopathic pulmonary fibrosis (IPF), and 18 patients with chronic obstructive bronchitis (COB). The retained particles were magnetized and aligned in an external 100 mT magnetic field. All magnetized particles induce a weak magnetic field of the lung, which was detected by a sensitive SQUID (superconducting quantum interference device) sensor. Cytoskeletal reorganizations within macrophages and intracellular transport cause stochastic magnetic dipole rotations, which are reflected in a decay of the magnetic lung field, called relaxation. Directed phagosome motion was induced in a weak magnetic twisting field. The resistance of the cytoplasm to particle twisting was characterized by the viscosity and the stiffness (ratio between stress to strain) of the cytoskeleton. RESULTS: One week after particle inhalation and later macrophage motility (relaxation) and cytoskeletal stiffness was not influenced by cigarette smoking, neither in healthy subjects, nor in the patients. Patients with IPF showed in tendency a faster relaxation (p = 0.06). Particle twisting revealed a non-Newtonian viscosity with a pure viscous and a viscoelastic compartment. The viscous shear was dominant, and only 27% of the shear recoiled and reflected viscoelastic properties. In patients with IPF, the stiffness was reduced by 60% (p < 0.02). An analysis of the shear rate and stress dependence of particle twisting allows correlating the rheological compartments to cytoskeletal subunits, in which microtubules mediate the pure viscous (non-recoverable) shear and microfilaments mediate the viscoelastic (recoverable) behavior. The missing correlation between relaxation and particle twisting shows that both stochastic and directed phagosome motion reflect different cytoskeletal mechanisms. CONCLUSION: Faster relaxation and a soft cytoskeleton in patients with IPF indicate alterations in cytoskeleton dependent functions of alveolar macrophages, which may cause dysfunction's in the alveolar defense, like a slower migration, a retarded phagocytosis, a disturbed phagosome lysosome fusion and an impaired clearance.

Journal Article↗

PubMed2006

Mucociliary and long-term particle clearance in airways of patients with immotile cilia.

Spherical monodisperse ferromagnetic iron oxide particles of 1.9 microm geometric and 4.2 microm aerodynamic diameter were inhaled by seven patients with primary ciliary dyskinesia (PCD) using the shallow bolus technique, and compared to 13 healthy non-smokers (NS) from a previous study. The bolus penetration front depth was limiting to the phase1 dead space volume. In PCD patients deposition was 58+/-8 % after 8 s breath holding time. Particle retention was measured by the magnetopneumographic method over a period of nine months. Particle clearance from the airways showed a fast and a slow phase. In PCD patients airway clearance was retarded and prolonged, 42+/-12 % followed the fast phase with a mean half time of 16.8+/-8.6 hours. The remaining fraction was cleared slowly with a half time of 121+/-25 days. In healthy NS 49+/-9 % of particles were cleared in the fast phase with a mean half time of 3.0+/-1.6 hours, characteristic of an intact mucociliary clearance. There was no difference in the slow clearance phase between PCD patients and healthy NS. Despite non-functioning cilia the effectiveness of airway clearance in PCD patients is comparable to healthy NS, with a prolonged kinetics of one week, which may primarily reflect the effectiveness of cough clearance. This prolonged airway clearance allows longer residence times of bacteria and viruses in the airways and may be one reason for increased frequency of infections in PCD patients.

Adult↗

PubMed2006

No significant translocation of inhaled 35-nm carbon particles to the circulation in humans.

Human pulmonary retention of 35 nm 99mTc-labeled carbonaceous particles, produced with a modified Technegas generator, was followed for 24 h using a gamma camera imaging technique. Nine healthy subjects and four asthmatics inhaled the test particles. Particle labeling stability was tested in vitro during 48 h. We also measured in vivo leaching in blood and in urine for 24 h. One additional subject was exposed to particles with unstable labeling. There were no significant differences between healthy and asthmatic subjects in any of the parameters studied. Particle retention after 24 h was 102% (SD +/- 4.7). Cumulative in vitro leaching of 99mTc activity from the particles was 1.7% (+/-1.1) after 24 h. In blood samples, 80 min after exposure, 1.1% (+/- 0.4) of initially deposited activity was detected and 91% of the activity was not bound to particles. In urine sampled during the first 24 h after exposure, 3.6% (+/- 0.9) of lung deposited activity was detected. Lung retention was 30% after 1 h in the subject exposed to the leaching aerosol (n = 1). Thirty-one percent of the deposited activity was detected in the blood after 80 min and 80% was not bound to particles. Fifty percent of the activity was excreted with urine within 24 h. On gamma camera images the activity visibly translocated from lungs to thyroid and gastrointestinal tract. In conclusion, over a 24-h period there was no significant translocation of inhaled 35-nm particles to the systemic circulation.

Aerosols↗

PubMed2006

Ultrafine particle-lung interactions: does size matter?

Epidemiological studies continue to indicate associations between exposure to increased concentrations of ambient fine and ultrafine particles and adverse health effects in susceptible individuals. The ultrafine particle fraction in the ambient atmosphere seems to play a specific role. Yet, the dosimetry (including deposition patterns in the respiratory tract and, particularly, the biokinetic fate of ultrafine particles) is not fully understood. In contrast to fine particles, inhaled ultrafine particles seem to follow different routes in the organism. Cardiovascular effects observed in epidemiological studies triggered the discussion on enhanced translocation of ultrafine particles from the respiratory epithelium towards circulation and subsequent target organs, such as heart, liver, and brain, eventually causing adverse effects on cardiac function and blood coagulation, as well as on functions of the central nervous system. Current knowledge on systemic translocation of ultrafine particles in humans and animal models is reviewed. Additionally, an estimate of accumulating particle numbers in secondary target organs during chronic exposure is extrapolated from long-term translocation data obtained from rats. Toxicological studies aim to provide the biological plausibility of health effects of ultrafine particles and to identify cascades of mechanisms that are causal for the gradual transition from the physiological status towards pathophysiologcal alterations and eventually chronic disease. Considering the interaction between insoluble ultrafine particles and biological systems (such as body fluids, proteins, and cells), there still are gaps in the current knowledge on how ultrafine particles may cause adverse reactions. This paper reviews the current concept of interactions between insoluble ultrafine particles and biological systems.

Aerosols↗

PubMed2005

Ultrafine particles cause cytoskeletal dysfunctions in macrophages: role of intracellular calcium.

BACKGROUND: Particulate air pollution is reported to cause adverse health effects in susceptible individuals. Since most of these particles are derived form combustion processes, the primary composition product is carbon with a very small diameter (ultrafine, less than 100 nm in diameter). Besides the induction of reactive oxygen species and inflammation, ultrafine particles (UFP) can cause intracellular calcium transients and suppression of defense mechanisms of alveolar macrophages, such as impaired migration or phagocytosis. METHODS: In this study the role of intracellular calcium transients caused by UFP was studied on cytoskeleton related functions in J774A.1 macrophages. Different types of fine and ultrafine carbon black particles (CB and ufCB, respectively), such as elemental carbon (EC90), commercial carbon (Printex 90), diesel particulate matter (DEP) and urban dust (UD), were investigated. Phagosome transport mechanisms and mechanical cytoskeletal integrity were studied by cytomagnetometry and cell viability was studied by fluorescence microscopy. Macrophages were exposed in vitro with 100 and 320 microg UFP/ml/million cells for 4 hours in serum free medium. Calcium antagonists Verapamil, BAPTA-AM and W-7 were used to block calcium channels in the membrane, to chelate intracellular calcium or to inhibit the calmodulin signaling pathways, respectively. RESULTS: Impaired phagosome transport and increased cytoskeletal stiffness occurred at EC90 and P90 concentrations of 100 microg/ml/million cells and above, but not with DEP or UD. Verapamil and W-7, but not BAPTA-AM inhibited the cytoskeletal dysfunctions caused by EC90 or P90. Additionally the presence of 5% serum or 1% bovine serum albumin (BSA) suppressed the cytoskeletal dysfunctions. Cell viability showed similar results, where co-culture of ufCB together with Verapamil, W-7, FCS or BSA produced less cell dead compared to the particles only.

Journal Article↗

PubMed2004

Mucociliary and long-term particle clearance in the airways of healthy nonsmoker subjects.

Spherical monodisperse ferromagnetic iron oxide particles of 1.9-microm geometric and 4.2-microm aerodynamic diameter were inhaled by 13 healthy nonsmoking subjects using the shallow bolus technique. The bolus width was 100 ml, and the penetration front depth was 150 +/- 27 ml. The mean flow rate during inhalation and exhalation was 250 ml/s. The Fowler dead space and the phase 1 dead space of the airways were 282 +/- 49 and 164 +/- 34 ml, respectively. Deposition was below 20% without breath holding and 51 +/- 8% after an 8-s breath-holding time. We attempted to confine the bolus deposition to the bronchial airways by limiting the bolus front depth to the phase 1 dead space volume. Particle retention was measured by the magnetopneumographic method over a period of 9 mo. Particle clearance from the airways showed a fast and a slow phase; 49 +/- 9% followed the fast phase with a mean half-time of 3.0 +/- 1.6 h and characterized the mucociliary clearance. The remaining fraction was cleared slowly with a half-time of 109 +/- 78 days. The slow clearance phase was comparable to clearance measurements from the lung periphery of healthy nonsmokers, which allowed macrophage-dependent clearance mechanisms of the slow cleared fraction to be taken into account. Despite the fact that part of the slowly cleared particles may originate from peripheral deposition, the data demonstrate that mucociliary clearance does not remove all particles deposited in the airways and that a significant fraction undergoes long-term retention mechanisms, the origin of which is still under discussion.

Adult↗

PubMed2004

Dosimetry and toxicology of ultrafine particles.

While epidemiological studies indicate an association between adverse health effects and ambient ultrafine particle concentrations in susceptible individuals, toxicological studies aim to identify mechanisms which are causal for the gradual transition from the physiological status towards patho-physiological disease. Impressive progress has been made in recent years when objectives changed from classical tests like lung function, etc. to endpoints comprising of particle induced oxidative stress, cell signaling and activation, release of mediators initiating inflammatory processes not only in the respiratory tract but also in the cardio-vascular system. Particularly, the large surface area of ultrafine particles provides a unique interface for catalytic reactions of surface-located agents with biological targets like proteins, cells, etc. However, toxicological studies are hampered by a number of imminent complications when simulating long-term exposure of humans in urban environments with inherited and/or acquired susceptibility (e.g., acute exposure studies at high concentrations either in human subjects or animal models). Yet, based on a conservative estimate results available begin to show an adverse health risk for susceptible individuals and support the epidemiological evidence.

Aerosols↗

PubMed2003

Effect of magnetic bead agglomeration on Cytomagnetometric measurements.

Magnetic twisting cytometry (MTC) is a novel tool to measure cytoskeleton-associated cell functions by the use of ferromagnetic microbeads. Magnetic beads are either incorporated by living cells by phagocytic processes or attached to integrin receptors to the cell membrane. The magnetic beads are magnetized and aligned in a strong magnetic field pulse. The application of twisting forces allows to investigate mechanical properties (stiffness, viscoelasticity) of the cytoskeleton of living cells by analyzing the magnetic cell field. Incorporated magnetic beads undergo intracellular transport processes, which result in a loss of particle alignment and in a decay of the remanent magnetic cell field. This process, called relaxation, depends on the mechanical cytoskeletal properties and can directly visualize the intracellular energy of cellular transport processes. The preparation of spherical monodisperse ferromagnetic beads made it possible to understand the above-described processes using mathematical models. Experimental conditions with many magnetic particles per cell enhances the formation of aggregates because of the attractive forces between magnetic spheres, resulting in a change of magnetic properties and of hydrodynamic behavior. Due to mutual magnetization, the remanent magnetic moment of an aggregate is stronger compared to the same number of single particles. This implies a higher cell field. Additionally the relaxation is retarded because of the change in shape factor and in volume, which also implies a faulty estimation of intracellular transport energy. Magnetic particle twisting is less influenced. In summary, valuable cytomagnetometric measurements have to be done with less than one particle per macrophage to ensure low probability of multiple particles per cell.

Animals↗

PubMed2002

Ultrafine particles cause cytoskeletal dysfunctions in macrophages.

Essential cytoskeletal functions of macrophages are migration, phagocytosis of foreign materials, and intracellular transport and digestion The influence of fine and ultrafine test particles (UFP), such as TiO(2), elemental carbon, commercial carbon black, diesel exhaust particulate matter, and urban dust (UrbD), on cytoskeleton-related functions of macrophages, such as phagocytosis, phagosome transport mechanisms, and mechanical cytoskeletal integrity, were studied by flow cytometry and by cytomagnetometry. Additionally, necrosis and apoptosis caused by the test particles was detected. The diameter of the test particles ranged from 12 to 220 nm and the Brunauer-Emmet-Teller specific surface area ranged from 6 to 600 m(2)/g. Primary alveolar macrophages from beagle dogs (BD-AM), obtained by bronchoalveolar lavage, were used as well as macrophages originating from the cell line J774A.1. For cytomagnetometry studies, spherical 1.8-microm ferromagnetic particles served as probes for cytoskeletal functions and were incubated together with the macrophages 24 h prior to UFP exposure. Macrophages were exposed in vitro with 10-320 microg UFP/ml/10(6) cells up to 24 h. In all experiments, J774A.1 macrophages were more sensitive than BD-AM to UFP exposure. Cytoskeletal dysfunctions evaluated by cytomagnetometry were an impaired phagosome transport and an increased cytoskeletal stiffness and occurred at concentrations of 100 microg UFP/ml/10(6) cells and above, in both BD-AM and J774A.1. Only fine TiO(2) did not show any effect. Urban dust (standard reference material 1649a) and diesel exhaust particles (DEP, standard reference material 1650) caused comparable cytoskeletal dysfunctions to elemental carbon with high specific surface area. Cytoskeletal dysfunctions induced by DEP or UrbD could be reduced after washing the particles by dichloromethane. UFP caused an impaired phagocytosis of 1-microm diameter fluorescent latex beads, inhibited cell proliferation, and decreased cell viability. All recorded cytotoxic parameters showed only weak correlations with the specific surface area or the total number of UFP, which can result from the different types of particles and different surface compositions. UFP cause cytoskeletal toxicity in vitro in macrophages, which can cause cellular dysfunctions, such as impaired proliferation, impaired phagocytic activity, and retarded intracellular transport processes as well as increased cell stiffness and can result in impaired defense ability in the lung.

Air Pollutants↗

PubMedDate not supplied

EDR is a stress-related survival factor from stroma and other tissues acting on early haematopoietic progenitors (E-Mix).

The erythroid differentiation regulator (EDR) is a highly conserved autocrine factor produced in many tissues. Its haemoglobin synthesis-inducing activity for human and murine erythroleukaemia cell lines had been detected in WEHI-3 conditioned medium. EDR functions were analysed in detail. It is released from cells immediately in response to various stressful conditions and enhances cell survival particularly at a lower concentration range and low cell density. At high cell density and high EDR concentration the opposite effect of an increase in cell death was observed. Its essential function within a tissue is considered to be the maintenance of growth homeostasis. Cells kept in culture for weeks show a decreasing responsiveness to EDR supply. This was also noted in freshly cloned EDR-responsive mouse erythroleukaemia cells pointing to a molecular adaptation process. Human haematopoietic progenitors were amplified 7-fold by EDR when kept at low cytokine levels. At saturating levels progenitors giving rise to at least two lineages in semisolid medium (E-mix) respond to EDR with an average 1.87-fold increase in colony numbers and a bell-shaped dose-response curve. Of the more mature BFU-E compartment a response was observed particularly in cases with low colony numbers. Given the release from irradiated stromal cells and the ability to partly substitute for stromal cells in the Burkitt's lymphoma cell line BL-70, EDR functions as a stromal survival factor for stroma-responsive cells.

Activins↗