Papers by Bernhard Michalke
Frontiers in Chemistry
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International Journal of Molecular Sciences
Element analysis in clinical or biological samples is important due to the essential role in clin... more Element analysis in clinical or biological samples is important due to the essential role in clinical diagnostics, drug development, and drug-effect monitoring. Particularly, the specific forms of element binding, actual redox state, or their spatial distribution in tissue or in single cells are of interest in medical research. This review summarized exciting combinations of sophisticated sample delivery systems hyphenated to inductively coupled plasma-mass spectrometry (ICP-MS), enabling a broadening of information beyond the well-established outstanding detection capability. Deeper insights into pathological disease processes or intracellular distribution of active substances were provided, enabling a better understanding of biological processes and their dynamics. Examples were presented from spatial elemental mapping in tissue, cells, or spheroids, also considering elemental tagging. The use of natural or artificial tags for drug monitoring was shown. In the context of oxidative...
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International Journal of Molecular Sciences, 2021
Background: Transition metals play a crucial role in brain metabolism: since they exist in differ... more Background: Transition metals play a crucial role in brain metabolism: since they exist in different oxidation states they are involved in ROS generation, but they are also co-factors of enzymes in cellular energy metabolism or oxidative defense. Methods: Paired serum and cerebrospinal fluid (CSF) samples were analyzed for iron, zinc, copper and manganese as well as for speciation using SEC-ICP-DRC-MS. Brain extracts from Mn-exposed rats were additionally analyzed with SEC-ICP-DRC-MS. Results: The concentration patterns of transition metal size fractions were correlated between serum and CSF: Total element concentrations were significantly lower in CSF. Fe-ferritin was decreased in CSF whereas a LMW Fe fraction was relatively increased. The 400–600 kDa Zn fraction and the Cu-ceruloplasmin fraction were decreased in CSF, by contrast the 40–80 kDa fraction, containing Cu- and Zn-albumin, relatively increased. For manganese, the α-2-macroglobulin fraction showed significantly lower con...
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Frontiers in Chemistry, 2021
Parkinson´s disease progression is linked to iron redox status homeostasis via reactive oxygen sp... more Parkinson´s disease progression is linked to iron redox status homeostasis via reactive oxygen species (ROS) formation, and lipids are the primary targets of ROS. The determination of iron redox status in vivo is challenging and requires specific extraction methods, which are so far tedious and very time-consuming. We demonstrated a novel, faster, and less laborious extraction method using the chelator ethylene glycol l-bis(β-aminoethyl ether)-N,N,N′,N′-tetra acetic acid (EGTA) as a stabilizing agent and synthetic quartz beads for homogenization under an argon atmosphere. Additionally, we combined the metal extraction with a well-established lipid extraction protocol using methyl-tert-butyl ether (MTBE) to avoid the problems of lipid precipitation in frozen samples and to determine lipid profiles and metal species from the same batch. The nonextractable matrix, such as the debris, is removed by centrifugation and digested to determine the total metal content of the sample as well. L...
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For humans Mn is an essential trace element, but at higher doses a neurotoxic metal. Chronic Mn e... more For humans Mn is an essential trace element, but at higher doses a neurotoxic metal. Chronic Mn exposure is affecting the central nervous system. Occupational Mn overexposure leads to an accumulation in the brain and has been shown to cause progressive, permanent, neurodegenerative damage with syndromes similar to idiopathic Parkinsonism. Mn is transported by an active mechanism across neural barriers (NB) finally into the brain, but to date modes of Mn neurotoxic action are poorly understood. This paper investigates the relevant Mn-carrier species which are responsible for a widely uncontrolled transport across NB. Mn speciation in paired serum/cerebrospinal fluid (CSF) samples was performed by size exclusion chromatography – inductively coupled plasma – dynamic reaction cell – mass spectrometry (SEC-ICP-DRC-MS) and capillary zone Mn-speciation for Mn-biomonitoring 118 electrophoresis (CZE) coupled to ICP-DRC-MS in an 2D approach for clear identification. The Mn-species from the di...
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Cancers, 2021
High-Z gold nanoparticles (AuNPs) conjugated to a targeting antibody can help to improve tumor co... more High-Z gold nanoparticles (AuNPs) conjugated to a targeting antibody can help to improve tumor control in radiotherapy while simultaneously minimizing radiotoxicity to adjacent healthy tissue. This paper summarizes the main findings of a joint research program which applied AuNP-conjugates in preclinical modeling of radiotherapy at the Klinikum rechts der Isar, Technical University of Munich and Helmholtz Zentrum München. A pharmacokinetic model of superparamagnetic iron oxide nanoparticles was developed in preparation for a model simulating the uptake and distribution of AuNPs in mice. Multi-scale Monte Carlo simulations were performed on a single AuNP and multiple AuNPs in tumor cells at cellular and molecular levels to determine enhancements in the radiation dose and generation of chemical radicals in close proximity to AuNPs. A biologically based mathematical model was developed to predict the biological response of AuNPs in radiation enhancement. Although simulations of a singl...
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Journal of Visualized Experiments, 2020
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Journal of Trace Elements in Medicine and Biology, 2018
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PloS one, 2015
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Inhalation Toxicology, 2006
The role of alveolar macrophages in the fate of ultrafine particles in the lung was investigated.... more The role of alveolar macrophages in the fate of ultrafine particles in the lung was investigated. Male Wistar-Kyoto rats were exposed to ultrafine gold particles, generated by a spark generator, for 6 h at a concentration of 88 microg/m3 (4 x 10(6)/cm3, 16 nm modal mobility diameter). Up to 7 days, the animals were serially sacrificed, and lavaged cells and lung tissues were examined by transmission electron microscopy. The gold concentration/content in the lung, lavage fluid, and blood was estimated by inductively coupled plasma-mass spectrometry. Gold particles used were spherical and electron dense with diameters of 5-8 nm. The particles were individual or slightly agglomerated. By inductively coupled plasma-mass spectrometry analysis of the lung, 1945 +/- 57 ng (mean +/- SD) and 1512 +/- 184 ng of gold were detected on day 0 and on day 7, respectively, indicating that a large portion of the deposited gold particles was retained in the lung tissue. In the lavage fluid, 573 +/- 67 ng and 96 +/- 29 ng were found on day 0 and day 7, respectively, which means that 29% and 6% of the retained gold particles were lavageable on these days. A low but significant increase of gold (0.03 to 0.06% of lung concentration) was found in the blood. Small vesicles containing gold particles were found in the cytoplasm of alveolar macrophages. In the alveolar septum, the gold particles were enclosed in vesicles observed in the cytoplasm of alveolar type I epithelial cells. These results indicate that inhaled ultrafine gold particles in alveolar macrophages and type I epithelial cells are processed by endocytotic pathways, though the uptake of the gold particles by alveolar macrophages is limited. To a low degree, systemic particle translocation took place.
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Applied Energy, 2015
ABSTRACT Due to current and upcoming regulations to address the adverse impacts of particulate ma... more ABSTRACT Due to current and upcoming regulations to address the adverse impacts of particulate matter (PM) from shipping emissions, the maritime sector is required to find energy-efficient ways to comply mainly by using low fuel sulfur content (FSC) in regulated seas. We studied the PM emission from a research ship diesel engine with fuel switching capability, optimized for HFO used at cruising, operated at representative engine loads resulting to varying excess O2 emission which was an indirect measurement of air–fuel mixture (λ), using heavy fuel oil (HFO, 1.6 S (%m)) and diesel fuel (DF, <0.001 S (%m)). We determined the characteristics and temporal evolution of the PM by using the High Resolution Time-of-Flight Aerosol Mass Spectrometry (HR-ToF-AMS) in combination with aethalometer, particle sizers, online gas phase, and filter measurements. The average emission factors were higher for HFO than for DF with relative percent differences of ∼200, ∼180, ∼150, and ∼145 for SO42−, inorganic elements, organic matter (OM), and PM2.5, respectively, while that for black carbon (BC) was similar for both fuels. The difference between HFO and DF in terms of carbonaceous emissions was higher at 100% and 25% than at 75% and 50% engine loads. The exhaust temperature (T) decreased with increasing λ leading to the enhanced emission of OM in HFO and reduced OM and BC emission in DF. Contributions of hydrocarbons and oxygenated hydrocarbons increased with λ for HFO and decreased with DF. Gas phase total hydrocarbon (THC) was well correlated with BC only for HFO and OM and BC for DF. Overall, using a lower FSC reduced average PM emissions, however, engine load, and λ were strongly linked to the characteristics and temporal evolution of major PM emissions. The information in this study may help the marine sector and policy-making process in evaluating and designing future solutions for shipping emission regulations and diagnostics.
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Antioxidants
The trace element selenium is of considerable interest due to its toxic and nutritional propertie... more The trace element selenium is of considerable interest due to its toxic and nutritional properties, which markedly differ according to the dose and the chemical form. It has been shown that excess selenium intake increases the risk of type 2 diabetes and, possibly, other metabolic diseases like hyperlipidemia and non-alcoholic fatty liver disease (NAFLD). For the latter, however, epidemiologic evidence is still limited. We carried out a cross-sectional study recruiting 137 healthy blood donors living in Northern Italy and assessed their exposure to selenium through different methods and measuring serum selenium species. We performed linear and spline regression analyses to assess the relation of selenium and its forms with serum alanine aminotransferase (ALT) levels, a marker of NAFLD. Urinary selenium levels were positively and somewhat linearly correlated with ALT (beta regression coefficient (β) 0.11). Conversely, the association of dietary selenium intake with ALT was positive u...
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International Journal of Environmental Research and Public Health
Cadmium is a metal that is toxic to humans, and the major source of cadmium exposure in the non-s... more Cadmium is a metal that is toxic to humans, and the major source of cadmium exposure in the non-smoking general population is diet. To identify major food sources and lower exposure from diet, an accurate estimate of dietary cadmium intake is needed. Hence, the objectives of this study are to develop a method to assess dietary cadmium intake using a biomarker measurement and to improve the estimation of dietary cadmium intake when using a food frequency questionnaire (FFQ). In a random sample of an Italian population, we collected dietary habits by FFQ and measured cadmium in foods and beverages. These data were used to compute the estimated weekly dietary intake (WDI) of cadmium (µg) by kilogram (kg) of body weight (bw) (WDIFFQ). We also measured fasting serum cadmium levels by inductively-coupled plasma mass spectrometry. We used these data to develop a model for the estimation of the biomarker-derived dietary cadmium intake (WDIbio). In the 51 subjects recruited, the median level...
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Neurobiology of Disease
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Frontiers in Chemistry
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Journal of trace elements in medicine and biology : organ of the Society for Minerals and Trace Elements (GMS), 2018
Intensive rice-wheat cultivation cycle in Northern belt of India in general and in the State of P... more Intensive rice-wheat cultivation cycle in Northern belt of India in general and in the State of Punjab in particular results in large volumes of straw and other post-harvest residue annually. The agricultural area, bordering the districts of Nawanshahr and Hoshiarpur, is popularly known as the seleniferous belt of India. The agri-residues, generated in seleniferous region of this state, are observed to contain significantly high concentration of selenium (Se). The present study was aimed to evaluate the Se uptake by different mushroom species: Pleurotus sajor-caju, Pleurotus ostreatus, Pleurotus citrinopileatus, Agaricus bisporus, and Volvariella volvacea, cultivated on Se-rich wheat and paddy straw from the seleniferous region. Wheat (Pleurotus species and A. bisporus) and paddy straw (V. volvacea) was inoculated with the mycelium spawn and left for 7-20 days, depending on the species, to grow. Control mushrooms were grown analogously using the agricultural residues from non-seleni...
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Journal of neurochemistry, Jan 27, 2018
For more than 150 years it is known that occupational overexposure of manganese (Mn) causes movem... more For more than 150 years it is known that occupational overexposure of manganese (Mn) causes movement disorders resembling Parkinson's disease (PD) and PD-like syndromes. However, the mechanisms of Mn toxicity are still poorly understood. Here, we demonstrate that Mn dose- and time-dependently blocks the protein translation of amyloid precursor protein (APP) and heavy-chain Ferritin (H-Ferritin), both iron homeostatic proteins with neuroprotective features. APP and H-Ferritin are post-transcriptionally regulated by iron responsive proteins (IRPs), which bind to homologous iron responsive elements (IREs) located in the 5'-untranslated regions (5'-UTRs) within their mRNA transcripts. Using reporter assays, we demonstrate that Mn exposure repressed the 5'-UTR-activity of APP and H-Ferritin, presumably via increased IRP-IRE binding, ultimately blocking their protein translation. Using two specific Fe -specific probes (RhoNox-1 and IP-1) and ion chromatography inductively ...
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Fresenius' Journal of Analytical Chemistry
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Fresenius' Journal of Analytical Chemistry
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Fresenius' Journal of Analytical Chemistry
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Papers by Bernhard Michalke