Mikronährstoffe: Nahrungsergänzungsmittel, Analytik, Essentialität und Toxizität (eBook)

Tanja Schwerdtle, Franziska Ebert, Andrea Hartwig (Hrsg.) (Herausgeber)

eBook Download: PDF

2011 | 1. Auflage
140 Seiten
Herbert Utz Verlag
978-3-8316-4053-9 (ISBN)

Infos

Die Jahrestagungen der Gesellschaft für Mineralstoffe und Spurenelemente e.v. (GMS) behandeln Themen an der Schnittstelle zwischen Medizin, Ernährung, Biologie, Chemie, Umwelt und verwandter naturwissenschaftlicher Disziplinen. Dieses Buch präsentiert die Beiträge anlässlich der 24. GMS Jahrestagung an der Technischen Universität Berlin. Im wissenschaftlichen Fokus der Tagung stand das Thema Nahrungsergänzung mit Mikronähstoffen. Es wurden experimentelle Vorgehensweisen zur Aufklärung der vielschichtigen Bedeutung von Mineralstoffen und Spurenelementen für den Menschen, Interventionsstudien zur Nahrungsergänzung, mögliche Wechselwirkungen zwischen Mikronährstoffen untereinander, sowie die damit verbundenen Anforderungen an die Speziationsanalytik vorgestellt und basierend auf 16 Vorträgen, 14 Kurz- bzw. Posterpräsentationen und einer „Roundtable“-Diskussion von nationalen und internationalen Teilnehmern ausführlich diskutiert. Insgesamt informiert dieser Tagungsband über die zentrale Rolle von Mineralstoffen und Spurenelementen in den Lebenswissenschaften und verdeutlicht nachdrücklich, dass in diesem spannenden Themenfeld noch viele Fragen offen sind.

Inhalt

Vorwort 6
Inhaltsverzeichnis 8
In vivo systemic regulation of phosphate homeostasis: role of FGF23-klotho axis 10
The mechanism of inactivation of human sulfite oxidase by arsenite: comparison of in vivo and in vitro effects 16
Antioxidant supplements: An evidence-based approach to health benefits and risks 23
Berücksichtigung individueller Mg-Zielwerte bei genetisch-bedingtem Mg-Mangel 28
Zinc homeostasis and the immune system 35
Speciation and Toxicological Relevance of Manganese in Humans 42
Minireview: Selenium, selenoproteins and cancer 48
Einfluss von Selen auf die Integrität des Genoms 56
Changes of trace element concentrations in liver and serum during the acute phase response 60
Comparison of nutritional relevant low molecular weight selenocompounds for their effects on selenoprotein P expression in human hepatocytes 67
Significantly higher selenoprotein W expression in hyperplastic polyps and villous colonic adenomas with high grade dysplasia compared to epithelium of normal colonic mucosa 72
Toxikologische Aspekte des Ultraspurenelements Antimon 77
Inhibition of base excision repair by the ultra trace element arsenite and its methylated metabolites in cellular and subcellular systems 82
Einfluss von Cadmium und Kupfer auf Proteine der Basenexzisionsreparatur 86
Molybdenum in Rat Colon and the Human Colon Carcinoma Cell line HT29 92
Insulin affects SePP expression on the transcriptional level 100
PTP1B seems to be one molecular link between selenium and liver triglyceride metabolism 105
Charakterisierung von Manganspezies in Sprague-Dawley Ratten nach Fütterung mit einer eisen- und manganreichen Standard Diät 111
Methylmercury Exposure in Relation to Fish Intake in a Hospital Employee Population. Preliminary Results 117
Blood Lead and Cadmium Levels in a Hospital Employee Population and Assiciated Risk Factors. Preliminary Results 126
Die Selenanalyse in sehr geringen Mengen humaner Spermienkerne mit der instrumentellen Neutronen-aktivierungsanalyse 134

Textauszug

Speciation and Toxicological Relevance of Manganese in Humans (S. 33-34)

Summary

Although manganese is an essential trace element, concerns are rising about the Mn exposure of humans being related to neurotoxic effects. This contribution summarizes aspects of this topic to provide updated information on Mn related investigations including chemical speciation of Mn-compounds. The paper shows considerations on sources of human exposure, like the use of methylcyclopentadienyl Mn tricarbonyl (MMT). Further, the paper deals with Mn levels in the human organism, showing normal Mn concentrations in various matrices, and continues with aspects of Mn toxicology.

Of specific concern is the transfer of Mn to the brain, the relevant neurotoxic target. Therefore, the contribution focuses on recent investigations on Mn speciation at the neural barriers: Mn concentrations in serum samples (before passing neural barriers), were around 1.7 ± 0.8 μg/L (n=5). In size exclusion chromatography most Mn appeared associated to proteins with a molecular mass corresponding to TF and albumin. However, a Mn peak around 700 Da was also observed, which was increasing with total Mn concentration. This finding could point to excess Mn being transported by a low molecular mass (LMM) carrier. Behind neural barriers, in cerebrospinal fluid (CSF), mostly LMM Mn ligands were found.

Using CZE-ICP-DRC-MS it was investigated, which of these ligands were actually present as Mn-complexes. 13 Mnspecies were monitored in CSF samples, most of them being identified: Mn-histidine, Mnfumarate, Mn-malate, inorganic Mn, Mn-oxal-acetate, Mn-α-keto-glutarate, Mn carrying NAD, Mn-citrate and Mn-adenosin. By far the most abundant Mn-species was Mn-citrate showing a concentration of 0.7 ± 0.1 μg Mn/L.

Introduction

Mn is an essential trace element for human beings. It is a component of several enzymes [1]. Further important functions of Mn include its essentiality for normal bone structure [1]. As early as 1837 the first case of occupational Mn intoxication had been reported. Since that time a large number of studies have been performed to investigate the uptake, metabolism, transport and toxicity of Mn predominantly on the basis of animal models. Several reviews on Mn have been published with focus on its (neuro-) toxicity from a medical or toxicological point of view [2, 3, 4] however, until recently Mn in biomedical samples was not the subject of element speciation analysis.

This contribution summarizes current knowledge about Mn exposure for humans, Mn uptake, metabolism and neurotoxicity, and finally some new developments in Mn speciation at the neural barriers are shown. Specifically the distribution of Mn to different molecular-size fractions of serum or CSF is described. SEC coupled online to ICP-DRC-MS was employed to analyze Mn species in serum (before passing barriers) and CSF (behind the barriers). CSF was then further analyzed by CZE-ICP-DRC-MS for improved identification of Mn species. More detailed information about the aspects and described investigations is given in references [5, 6, 7]."

Produkt-Details

• Erscheint lt. Verlag: 1.1.2011
• Sprache: deutsch
• Themenwelt: Medizin / Pharmazie ► Allgemeines / Lexika
• ISBN-10: 3-8316-4053-X / 383164053X
• ISBN-13: 978-3-8316-4053-9 / 9783831640539