title: Lack of promoting effects of chronic exposure to 1.95-GHz W-CDMA signals for IMT-2000 cellular system on development of N-ethylnitrosourea-induced central nervous system tumors in F344 rats.
abstract: The present study was performed to evaluate effects of a 2-year exposure to an electromagnetic near-field (EMF) equivalent to that generated by cellular phones on tumor development in the central nervous system (CNS) of rats. For this purpose, pregnant F344 rats were given a single administration of N-ethylnitrosourea (ENU) on gestational day 18. A total of 500 pups were divided into five groups, each composed of 50 males and 50 females: Group 1, untreated controls; Group 2, ENU alone; Groups 3 to 5, ENU + EMF (sham exposure and two exposure levels). A 1.95-GHz wide-band code division multiple access (W-CDMA) signal, which is a feature of the International Mobile Telecommunication 2000 (IMT-2000) cellular system was employed for exposure of the rat head starting from 5 weeks of age, 90 min a day, 5 days a week, for 104 weeks. Brain average specific absorption rates (SARs) were designed to be .67 and 2.0 W/kg for low and high exposures, respectively. The incidence and numbers of brain tumors in female rats exposed to 1.95-GHz W-CDMA signals showed tendencies to increase but without statistical significance. Overall, no significant increase in incidences or numbers, either in the males or females, was detected in the EMF-exposed groups. In addition, no clear changes in tumor types in the brain were evident. Thus, under the present experimental conditions, exposure of heads of rats to 1.95-GHz W-CDMA signals for IMT-2000 for a 2-year period was not demonstrated to accelerate or otherwise affect ENU-initiated brain tumorigenesis.
authors.affiliation: Department of Experimental Pathology and Tumor Biology, Nagoya City University Graduate School of Medical Sciences, Nagoya, Japan. tshirai@med.nagoya-cu.ac.jp
authors.forename: Tomoyuki
authors.initials: T
authors.lastname: Shirai
authors.forename: Toshio
authors.initials: T
authors.lastname: Ichihara
authors.forename: Kanako
authors.initials: K
authors.lastname: Wake
authors.forename: So-ichi
authors.initials: S
authors.lastname: Watanabe
authors.forename: Yukio
authors.initials: Y
authors.lastname: Yamanaka
authors.forename: Mayumi
authors.initials: M
authors.lastname: Kawabe
authors.forename: Masao
authors.initials: M
authors.lastname: Taki
authors.forename: Osamu
authors.initials: O
authors.lastname: Fujiwara
authors.forename: Jianqing
authors.initials: J
authors.lastname: Wang
authors.forename: Satoru
authors.initials: S
authors.lastname: Takahashi
authors.forename: Seiko
authors.initials: S
authors.lastname: Tamano
mesh_terms: D000818:Animals; D001932:Brain Neoplasms / Q000209:etiology* / Q000473:pathology*; D040421:Cell Phone; D004305:Dose-Response Relationship, Drug; D004307:Dose-Response Relationship, Radiation; D004574:Electromagnetic Fields; D004781:Environmental Exposure; D005038:Ethylnitrosourea; D005260:Female; D008297:Male; D009381:Neoplasms, Radiation-Induced / Q000209:etiology* / Q000473:pathology*; D011829:Radiation Dosage; D051381:Rats; D011916:Rats, Inbred F344
chemical_list: D005038:Ethylnitrosourea