Medizinische/biologische Studie (experimentelle Studie)

Extremely low-frequency electromagnetic fields do not affect DNA damage and gene expression profiles of yeast and human lymphocytes med./bio.

[Extrem niederfrequente elektromagnetische Felder beeinflussen nicht den DNA-Schaden und die Genexpressions-Profile von Hefe und menschlichen Lymphozyten]

Von: Luceri C, De Filippo C, Giovannelli L, Blangiardo M, Cavalieri D, Aglietti F, Pampaloni M, Andreuccetti D, Pieri L, Bambi F, Biggeri A, Dolara P

Veröffentlicht in: Radiat Res 2005; 164 (3): 277-285

Referenz im RIS-Format herunterladen

Ziel der Studie (lt. Autor)

Es sollten die Wirkungen extrem niederfrequenter elektromagnetischer Felder auf die peripheren Blut-Lymphozyten des Menschen und Hefe untersucht werden.

Endpunkt

Genotoxizität/Mutation: DNA-Schaden

Exposition/Befeldung (teilweise nur auf Englisch)

Exposition	Parameter
Exposition 1: 50 Hz Expositionsdauer: kontinuierlich für 18 Stunden	magnetische Flussdichte: 0,1 µT magnetische Flussdichte: 1 µT magnetische Flussdichte: 10 µT magnetische Flussdichte: 100 µT

Exposition 1

Hauptcharakteristika

Frequenz	50 Hz
Typ	elektromagnetisches Feld
Signalform	sinusoidal
Expositionsdauer	kontinuierlich für 18 Stunden
Zusatzinfo	reference article: D. Andreuccetti, M. Bini, A. Ignesti, R. Olmi, S. Priori and R. Vanni, Helmholtz coils for the generation of standard magnetic fields in biological applications. Proceedings of the VII National Congress of the AIFB, Monte Conero, Ancona (Italy), June 1992. Phys. Med. IX (Suppl. 1), 283-285 (1993).

Expositionsaufbau

Expositionsquelle	Helmholtz-Spule see setup details
Aufbau	The HC-50 exposure system consisted of a Helmholtz pair system comprising two parallel, coaxial, circular coils having a diameter of 40.6 cm. The distance between coils was equal to their radius (20.3 cm). Each coil was made up of 16 turns of 0.5-mm-thick enamelled copper wire. The two coils were connected in series so that the same current flowed in both. The field strength was regulated by varying the drive current supplied by an adjustable power unit allowing the HC-50 to produce a 50 Hz magnetic flux density varying from 1 to more than 150 µT.
Zusatzinfo	Each lymphocyte population was divided into two aliquots. The exposed cell aliquots were incubated at the desired field intensity in a cell incubator containing the HC-50 Helmholtz coil system, and the unexposed cell aliquots were placed in a second incubator used in parallel. As an additional control, some experiments were performed by reversing the current in one of the coils in the HC-50 (sham exposure).

Parameter

Messgröße	Wert	Typ	Methode	Masse	Bemerkungen
magnetische Flussdichte	0,1 µT	-	gemessen	-	-
magnetische Flussdichte	1 µT	-	Kalibrierung	-	-
magnetische Flussdichte	10 µT	-	Kalibrierung	-	-
magnetische Flussdichte	100 µT	-	Kalibrierung	-	-

Mess- und Berechnungsdetails

The actual magnetic flux density is a vector function of the position inside the Helmholtz coil system (being exactly equal to the nominal magnetic flux density in the system center only), but calculations and measurements show that intensity and direction errors with respect to the nominal magnetic flux density are less than 1% in a spherical volume centered in the system center and having a radius equal to one third of the coil radius, i.e. approx, 7 cm in the HC-50. The HC-50 power supply unit was equipped with a solid-state current meter whose LCD was calibrated to indicate the nominal magnetic flux density in microtesla. Scrupulous construction and precise calibration of the current meter guaranteed the overall accuracy, which was within 3% of the 7-cm-radius spherical volume. Although the system accuracy is too high to be assessed with standard magnetic flux density meters (rather the HC-50 itself can be used as a calibration device for such probes), it was checked and confirmed as far as possible with a professional commercial magnetic flux density meter (EMDEX II by Enertech consultants); the same instrument was also used to evaluate the background field intensity in the incubators and in the environment where cell exposure took place.

Exponiertes System:

intakte Zelle/Zellkultur (in vitro)
Hefe (Saccharomyces cerevisiae/Stamm DBY747)

Methoden Endpunkt/Messparameter/Methodik

Genotoxizität/Mutation: DNA-Schaden (Strangbrüche) und oxidierte Basen (Comet-Assay)
molekulare Biosynthese: Genexpressions-Profile (Microarray)

Untersuchtes System:

DNA/RNA (in vitro)
intakte Zelle/Zellkultur (in vitro)

Untersuchungszeitpunkt:

nach der Befeldung

Hauptergebnis der Studie (lt. Autor)

Nach der Exposition bei dem elektromagnetischen Feld wurde kein Anstieg bei der Menge der Strangbrüche oder oxidierter DNA-Basen im Vergleich zu den Kontrollen beobachtet, ebenso keine Veränderung der Genexpressions-Profile. Die Ergebnisse deuten darauf hin, dass extrem niederfrequente elektromagnetische Felder keinen DNA-Schaden hervorrufen oder die Genexpression in diesen beiden eukaryotischen Zell-Systemen nicht beeinträchtigen.

Studienmerkmale:

medizinische/biologische Studie
experimentelle Studie
Voll-/Hauptstudie

Studie gefördert durch

Ministero delle attività produttive (Ministry for Productive Activities), Italy

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