Medizinische/biologische Studie (experimentelle Studie)

HSP27 phosphorylation increases after 45°C or 41°C heat shocks but not after non-thermal TDMA or GSM exposures med./bio.

[Die HSP27-Phosphorylierung steigt im Anschluss an 45°C bzw. 41°C Hitzeschocks, aber nicht nach nicht-thermischen TDMA- oder GSM-Expositionen]

Von: Vanderwaal RP, Cha B, Moros EG, Roti Roti JL

Veröffentlicht in: Int J Hyperthermia 2006; 22 (6): 507-519

Ziel der Studie (lt. Autor)

In dieser in vitro-Studie sollte untersucht werden, ob durch Hyperthermie-Exposition oder durch nicht-thermische Hochfrequenz-Exposition Veränderungen in der Hitzeschock-Protein 27 (HSP27)-Phosphorylierung bei menschlichen Zelllinien herbeigeführt werden kann.

Hintergrund/weitere Details

Es wurden fünf unterschiedliche Isoformen des Hitzeschock-Proteins 27 (HSP27) berücksichtigt.
Jedes Experiment wurde dreimal wiederholt.

Endpunkt

molekulare Biosynthese: Hitzeschock-Protein 27 (HSP27)-Phosphorylierung

Exposition/Befeldung (teilweise nur auf Englisch)

- TDMA
- Mobilfunk
- GSM

Exposition	Parameter
Exposition 1: 847 MHz Modulationsart: gepulst Expositionsdauer: kontinuierlich für 1, 2 oder 24 h	SAR: 5 W/kg Mittelwert
Exposition 2: 900 MHz Modulationsart: gepulst Expositionsdauer: kontinuierlich für 1, 2 oder 5 h	SAR: 3,7 W/kg Mittelwert

Exposition 1

Hauptcharakteristika

Frequenz	847 MHz
Typ	elektromagnetisches Feld
Charakteristik	gerichtetes Feld
Expositionsdauer	kontinuierlich für 1, 2 oder 24 h

Modulation

Modulationsart	gepulst
Zusatzinfo	TDMA

Expositionsaufbau

Expositionsquelle	radialer Wellenleiter
Abstand zw. exponiertem Objekt und Expositionsquelle	292 mm
Kammer	A detailed description of the radial transmission line used for exposure has been reported in several publications [Moros et al., 1998 and 1999]. The RTL was formed by two horizontal parallel conductive plates, 43 mm apart. The 6 mm thick bottom AL plate was highly thermally conductive thus minimising temperature gradients among flasks. A central conical AL antenna emitted TEM waves propagating radially outward and terminated by an annulus of RF-absorbing foam material braced by a thin lamina of perforated aluminium at 533 mm from the centre.
Aufbau	A total of 16 T-75 culture flasks could be distributed angularly around the antenna with their centres located at a radius of 292 mm. The cell layer was between 247 and 338 mm from the centre. Each flask was dielectrically loaded with a 3 mm thick shim of alumina (Al₂O₃) in order to boost and homogenise the SAR distribution.
Schein-Exposition	Eine Schein-Exposition wurde durchgeführt.
Zusatzinfo	Cells in T-75 tissue culture flasks containing 40 ml of medium (height 5 mm) were exposed to RF radiation at 37°C or heat shock (2 h at 41°C or 30 min at 45°C). All heat shock and RF exposure conditions were analysed simultaneously along with a matched incubator control sample.

Parameter

Messgröße	Wert	Typ	Methode	Masse	Bemerkungen
SAR	5 W/kg	Mittelwert	gemessen	-	-

Zusätzliche Parameterdetails

"The above power settings were selected to produce a nominal time-averaged cell-layer SAR of 5.0 ± 2.1 W/kg for both signals." (?!)

Mess- und Berechnungsdetails

This SAR value is based on a series of comprehensive measurements and includes variations due to the position of the flask but does not include potential measurement uncertainty usually estimated at ±10%. The degree of inhomogeneity (SD) is typical for this type of arrangement and has been validated by independent FDTD simulation studies [Pickard et al., 2000, publication 5405]. The larger than usual amount of medium was found to reduce the SAR non-uniformities.

Exposition 2

Hauptcharakteristika

Frequenz	900 MHz
Typ	elektromagnetisches Feld
Charakteristik	gerichtetes Feld
Expositionsdauer	kontinuierlich für 1, 2 oder 5 h

Modulation

Modulationsart	gepulst
Zusatzinfo	GSM

Expositionsaufbau

Expositionsquelle	gleicher Aufbau wie Exposition 1
Schein-Exposition	Eine Schein-Exposition wurde durchgeführt.

Parameter

Messgröße	Wert	Typ	Methode	Masse	Bemerkungen
SAR	3,7 W/kg	Mittelwert	gemessen	-	-

Zusätzliche Parameterdetails

"The above power settings were selected to produce a nominal time-averaged cell-layer SAR of 5.0 ± 2.1 W/kg for both signals." (?!)

Referenzartikel

Moros EG et al. (1999): The radial transmission line as a broad-band shielded exposure system for microwave irradiation of large numbers of culture flasks
Moros EG et al. (1998): A compact shielded exposure system for the simultaneous long-term UHF irradiation of forty small mammals: I. Electromagnetic and environmental design

Exponiertes System:

intakte Zelle/Zellkultur (in vitro)
HeLa S3 (menschliche Zervix-Karzinom-Zelllinie), EA.hy926 (menschliche Endothel-Zelllinie)

Methoden Endpunkt/Messparameter/Methodik

molekulare Biosynthese: Hitzeschock-Protein 27 (HSP27)-Phosphorylierung (SDS-Poylacrylamidgel-Elektrophorese, Immunoblot)

Untersuchtes System:

isolierte biol./chemische Substanz (in vitro)

Untersuchungszeitpunkt:

nach der Befeldung

Hauptergebnis der Studie (lt. Autor)

Eine Hyperthermie-Exposition (akut 30 Minuten bei 45 °C, chronisch zwei Stunden bei 45 °C) steigerte signifikant die Hitzeschock-Protein 27 (HSP27)-Phosphorylierung.
Keine signifikanten Unterschiede in den Spiegeln der Hitzeschock-Protein 27 (HSP27)-Phoshorylierungen wurde bei TDMA-exponierten HeLa S3-Zellen beobachtet.
Die Exposition bei 900 MHz GSM führte zu keinen signifikanten Unterschieden in den Spiegeln der Hitzeschock-Protein 27 (HSP27)-Phosphorylierungen bei EA.hy926-Zellen.

Studienmerkmale:

medizinische/biologische Studie
experimentelle Studie
Voll-/Hauptstudie

Studie gefördert durch

Mobile Manufacturers Forum (MMF), Belgium
National Cancer Institute (NCI; U.S. National Institutes of Health), Maryland, USA

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