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

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.     

Effects of RF exposure of teenagers and adults by CDMA cellular phones

Many cellular phone provocation studies have been conducted since the question of increased health risk from extended usage of cellular phones became a social issue. Internationally, most studies have been conducted regarding the effects of GSM cellular phones on blood pressure and heart rate of adult volunteers. On the other hand, very few provocation studies have been conducted regarding the physiological effects of CDMA phones on teenagers. In this study, two volunteer groups consisting of 21 teenagers and 21 adults were exposed to 300 mW of radio frequency (RF) electromagnetic field emitted by a CDMA cellular phone for half an hour. Physiological parameters such as systolic and diastolic blood pressures, heart rate, respiration rate, and skin resistance were simultaneously measured. All the parameters for both groups were unaffected during the exposure except for decreased skin resistance of the teenager group (P < .0001). For the regrouped 23 male and 19 female subjects, all the parameters for both groups were unaffected during the exposure except for decreased skin resistance of the male subjects (P = .0026). Those resistances at 10 min after the terminated exposure returned to the resistances at rest regardless of the different groups of age and sex.     

Chronic exposure to a 1.439 GHz electromagnetic field used for cellular phones does not promote N-ethylnitrosourea induced central nervous system tumors in F344 rats

The present study was designed to evaluate whether a 2 year exposure to an electromagnetic field (EMF) equivalent to that generated by cellular phones can accelerate tumor development in the central nervous system (CNS) of rats. Brain tumorigenesis was initiated by an intrauterine exposure to 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 control; Group 2, ENU alone; Groups 3-5, ENU + EMF (sham exposure and 2 exposure levels). A 1.439 GHz time division multiple access (TDMA) signal for the Personal Digital Cellular (PDC), Japanese standard cellular system was used for the 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 rate (SAR) was 0.67 and 2.0 W/kg for low and high exposures, respectively: whole body average SAR was less than 0.4 W/kg. There were no inter-group differences in body weights, food consumption, and survival rates. No increase in the incidences or numbers per group of brain and/or spinal cord tumors, either in the males or females, was detected in the EMF exposed groups. In addition, no clear changes in tumor types were evident. Thus, under the present experimental conditions, 1.439 GHz EMF exposure to the heads of rats for a 2 year period was not demonstrated to accelerate or affect ENU initiated brain tumorigenesis.     

Effects of W‐CDMA 1950 MHz EMF emitted by mobile phones on regional cerebral blood flow in humans

Use of the third generation mobile phone system is increasing worldwide. This is the first study to investigate the effects of the third generation system on regional cerebral blood flow (rCBF) in humans. We compared effects of the electromagnetic field (EMF) emitted from the Wideband Code Division Multiple Access (W‐CDMA) cellular system versus sham control exposure on rCBF in humans. Nine healthy male volunteers participated in this study. Positron emission tomography (PET) scans were obtained before, during, and after unilateral 30 min EMF exposure. The subtraction analysis revealed no significant rCBF changes caused by the EMF conditions compared with the sham exposure, suggesting that EMF emitted by a third generation mobile phone does not affect rCBF in humans. Bioelectromagnetics 30:536–544, 2009. © 2009 Wiley‐Liss, Inc.     

妊娠期给予可卡因对母体和胎儿的影响: 小鼠动物模型

探讨妊娠期给予可卡因对母体和胎儿的影响。妊娠小鼠分为3组：可卡因注射组（每日两次注射盐酸可卡因10mg/kg,COC);盐水对照组（每日两次注射生理盐水10ml/kg,SAL);饮食对照组（每日两次注射生理盐水10ml/kg,饮食参考可卡因给药组,SPF）。用高压液相色谱分析法检测胎鼠血中可卡因浓度及纹状体中神经递质多巴胺和5－羟色胺的含量,并结合HE染色观察胎鼠肝脏和胎盘的形态学改变。尽管COC和SPF组母鼠摄食量和体重增长量均降低,但是仅仅COC组胎鼠的体重和脑重减少。高压液相色谱分析结果显示,在COC组胎鼠血浆中可检测出可卡因,并伴有纹状体神经递质含量的异常增高。同时,也观察到了COC组胎盘和肝脏的形态学变化。本研究表明,妊娠期给予可卡因能引起妊娠母体营养不良,子代脑、肝脏和胎盘发育异常;可卡因引起的胎儿发育异常是由可卡因的毒性作用而不是母体营养不良产生的。     

Effects of long-term exposure to 900 megahertz electromagnetic field on heart morphology and biochemistry of male adolescent rats

The pathological effects of exposure to an electromagnetic field (EMF) during adolescence may be greater than those in adulthood. We investigated the effects of exposure to 900 MHz EMF during adolescence on male adult rats. Twenty-four 21-day-old male rats were divided into three equal groups: control (Cont-Gr), sham (Shm-Gr) and EMF-exposed (EMF-Gr). EMF-Gr rats were placed in an EMF exposure cage (Plexiglas cage) for 1 h/day between postnatal days 21 and 59 and exposed to 900 MHz EMF. Shm-Gr rats were placed inside the Plexiglas cage under the same conditions and for the same duration, but were not exposed to EMF. All animals were sacrificed on postnatal day 60 and the hearts were extracted for microscopic and biochemical analyses. Biochemical analysis showed increased levels of malondialdehyde and superoxide dismutase, and reduced glutathione and catalase levels in EMF-Gr compared to Cont-Gr animals. Hematoxylin and eosin stained sections from EMF-Gr animals exhibited structural changes and capillary congestion in the myocardium. The percentage of apoptotic myocardial cells in EMF-Gr was higher than in either Shm-Gr or Cont-Gr animals. Transmission electron microscopy of myocardial cells of EMF-Gr animals showed altered structure of Z bands, decreased myofilaments and pronounced vacuolization. We found that exposure of male rats to 900 MHz EMF for 1 h/day during adolescence caused oxidative stress, which caused structural alteration of male adolescent rat heart tissue.     

Growth characteristics of mung beans and water convolvuluses exposed to 425‐MHz electromagnetic fields

Effects of high‐frequency, continuous wave (CW) electromagnetic fields on mung beans (Vigna radiata L.) and water convovuluses (Ipomoea aquatica Forssk.) were studied at different growth stages (pre‐sown seed and early seedling). Specifically, the effects of the electromagnetic source's power and duration (defined as power‐duration level) on the growth of the two species were studied. Mung beans and water convolvuluses were exposed to electromagnetic fields inside a specially designed chamber for optimum field absorption, and the responses of the seeds to a constant frequency at various power levels and durations of exposure were monitored. The frequency used in the experiments was 425 MHz, the field strengths were 1 mW, 100 mW, and 10 W, and the exposure durations were 1, 2, and 4 h. Results show that germination enhancement is optimum for the mung beans at 100 mW/1 h power‐duration level, while for water convolvuluses the optimum germination power‐duration level was 1 mW/2 h. When both seed types were exposed at the early sprouting phase with their respective optimum power‐duration levels for optimum seed growth, water convolvuluses showed growth enhancement while mung bean sprouts showed no effects. Water content analysis of the seeds suggests thermal effects only at higher field strength. Bioelectromagnetics 31:519–527, 2010. © 2010 Wiley‐Liss, Inc.     

Effects of 5‐HT1 and 5‐HT 2 Receptor Agonists on Electromagnetic Field‐Induced Analgesia in Rats

Much evidence demonstrates the antinociceptive effect of magnetic fields (MFs). However, the analgesic action mechanism of the electromagnetic field (EMF) is not exactly understood. The aim of the present study was to investigate the effects of 5‐HT₁ and 5‐HT₂ receptor agonists (serotonin HCl and 2,5‐dimethoxy‐4‐iodoamphetamine [DOI] hydrochloride) on EMF‐induced analgesia. In total, 66 adult male Wistar albino rats with an average body mass of 225 ± 13 g were used in this study. The animals were subjected to repeated exposures of alternating 50 Hz and 5 mT EMF for 2 h a day for 15 days. Prior to analgesia tests, serotonin HCl (5‐HT₁ agonist) 4 mg/kg, WAY 100635 (5‐HT₁ antagonist) 0.04 mg/kg, DOI hydrochloride (5‐HT₂ receptor agonist) 4 mg/kg, and SB 204741 (5‐HT₂ antagonist) 0.5 mg/kg doses were injected into rats. For statistical analysis of the data, analysis of variance was used and multiple comparisons were determined by Tukey’s test. Administration of serotonin HCl MF (5 mT)‐exposed rats produced a significant increase in percent maximal possible effect (% MPE) as compared with EMF group (P < 0.05). On the contrary, injection of WAY 100635 to MF‐exposed rats produced a significant decrease in analgesic activity (P < 0.05). Similarly, the administration of DOI hydrochloride significantly increased % MPE values as compared with the EMF group while SB 204741 reduced it (P < 0.05). In conclusion, our results suggested that serotonin 5‐HT₁ and 5‐HT₂ receptors play an important role in EMF‐induced analgesia; however, further research studies are necessary to understand the mechanism. Bioelectromagnetics. 2019;40:319–330. © 2019 Bioelectromagnetics Society.     

Effect of exposure to 50 Hz magnetic field with or without insulin on blood–brain barrier permeability in streptozotocin‐induced diabetic rats

We investigated the effect of long‐term exposure to modulation magnetic field (MF), insulin, and their combination on blood–brain barrier (BBB) permeability in a diabetic rat model. Fifty‐three rats were randomly assigned to one of six groups: sham, exposed to no MF; MF, exposed to MF; diabetes mellitus (DM), DM induced with streptozotocin (STZ); DM plus MF (DMMF); DM plus insulin therapy (DMI); and DM plus insulin therapy plus MF (DMIMF). All the rats underwent Evans blue (EB) measurement to evaluate the BBB 30 days after the beginning of experiments. The rats in MF, DMMF, and DMIMF groups were exposed to MF (B = 5 mT) for 165 min every day for 30 days. Mean arterial blood pressure (MABP), body mass, and serum glucose level of the study rats were recorded. The extravasation of brain EB of the MF, DM, DMMF, DMI, and DMIMF groups was higher than that of the sham group and the extravasation of right hemisphere of the DMIMF group was highest (P < 0.05). The post‐procedure body mass of the sham and MF groups were significantly higher than those of the DM and DMMF groups (P < 0.05). In the DM, DMMF, DMI, and DMIMF groups, the baseline glucose was significantly lower than the post‐procedure glucose (P < 0.05). DM and MF increase BBB permeability; in combination, they cause more increase in BBB permeability, and insulin decreases their effect on BBB. Improved glucose metabolism may prevent body mass loss and the hypoglycemic effect of MF. DM increases MABP but MF causes no additional effect. Bioelectromagnetics 31:262–269, 2010. © 2009 Wiley‐Liss, Inc.     

Effect in rats of simultaneous prenatal exposure to ochratoxin A and aflatoxin B1. I. Maternal toxicity and fetal malformations

Ochratoxin A (OA) and Aflatoxin B1 (AFB1), the food borne mycotoxins are produced by several fungal species of the genera Aspergillus and Penicillium. To determine the teratogenic effects, these mycotoxins were administered orally either individually or in combination to the pregnant Wistar rats on days 6-15 of gestation. OA and AFB1 were dissolved in corn oil and different doses of OA (0.125, 0.25, 0.50, and 0.75 mg/kg), AFB1 (0.125, 0.25, 0.50, and 1.00 mg/kg), and a combination of OA+AFB1 (0.125+0.125; 0.25+0.50; 0.50+0.25 mg/kg) were given by gastric intubation to rats. During dosing period, the body weight and body weight gains significantly decreased at a higher dosage, in both individual and combined treatments. In all the combination treatments, the percent implants resorbed, fetal body weights, and crown-rump lengths were comparable to those of controls and with the individual mycotoxin treatment. The number of dead fetuses was significantly increased in the high OA combination (OA+AFB1 0.50+0.25) group as compared with the other two combinations. OA and AFB1 alone and in combination caused various gross, skeletal, and visceral anomalies. The occurrence was considerably less pronounced in fetuses of AFB1 and combination groups as compared with those of OA group fetuses. The exencephaly, incomplete closure of skull, wavy and fused ribs, agenesis of the ischium bone, and enlarged renal pelvis, recorded in OA treatment and ear abnormality and incomplete ossification of skull bones observed in AFB1 when given individually, were not seen in combination groups. However, new manifestations, such as gastroschisis and syndactyly were observed and the incidence of cardiac defects was increased in fetuses due to the combined treatment. The results of the present study indicated that there is some interaction between these mycotoxins that resulted in reduced teratogenic activity of OA in the presence of AFB1. Apparently, new manifestations observed in combination treatment points to the potential threat of teratogenicity in terms of public health hazards.     

Perinatal exposure to 60-Hz electric fields: Effects on the development of the visual-evoked response in rats

Two independent series of experiments were performed on 114 male Sprague-Dawley derived, albino rat pups, which represented 61 litters in experimental series I and 53 litters in experimental series II. Animals were exposed for 20 h/day from conception to testing (postnatal days 11–20) to a vertical, 65-kV/m, 60-Hz electric field or sham-exposed. Recordings of the visual-evoked response (VER) were obtained using a small silver ball electrode placed epidurally over the visual cortex. Visual stimuli consisted of 10-μS light flashes delivered at 0.2 Hz. Computer-averaged VERs were obtained and power spectral analyses (fast Fourier transform) were performed on the tapered (split cosine-bell window), averaged VERs. The expected age-related changes were clearly evident; however, a detailed analysis of VER component latencies, peak-to-peak amplitude, and power spectra failed to reveal any consistent, statistically significant effect of exposure to 60-Hz electric fields.     

Effects of exposure to a circularly polarized 50-Hz magnetic field on plasma and pineal melatonin levels in rats

We sought to determine whether a 6-week exposure to a 50-Hz rotating magnetic field influences melatonin synthesis by 11–18 week-old Wistar-King male rats. Rats were exposed continuously to a rotating magnetic field at 1, 5, 50, or 250 μT (spatial vector rms) for 6 weeks, except for twice-weekly breaks of about 2 h for cleaning of cages and feeding. The rats were housed in exposure and sham-exposure facilities, which were located in the same room, under a 12:12 light-dark photoperiod (lights on at 06:00 h). The room was constantly illuminated by 4 small, dim red lights (< 0.07 lux in dark period). Levels of plasma and pineal gland melatonin were determined by radioimmunoassay. A significant decrease of melatonin was observed between the control group and groups exposed to a magnetic field at a flux density in excess of l μT during the night time, but no statistical differences were found among the exposed groups. These results indicate that subchronic exposure of albino rats to a 50-Hz rotating magnetic field influences melatonin production and secretion by the pineal gland. © 1993 Wiley-Liss, Inc.     

Effects of Maternal Exposure to Imazalil on Behavioral Development in F1‐Generation Mice

Female mice were exposed maternally to imazalil through diet to provide levels of 0 (control), 0.0006, 0.0018, and 0.0054% during gestation and lactation periods, and selected reproductive and neurobehavioral parameters were measured in F₁ generation. There was no adverse effect of imazalil on litter size, litter weight, or sex ratio at birth. With respect to behavioral developmental parameters, surface righting on postnatal day 4 of male offspring was delayed significantly in a dose‐related manner (p < 0.05). Regarding exploratory behavior in the F₁ generation, movement time was significantly long (p = 0.0206) in the low‐dose group of males at 8 weeks of age. Spontaneous behavior examination in males indicated that movement time increased but in females decreased in the low‐dose groups in the F₁ generation. The dose levels of imazalil in the present study produced some adverse effects in neurobehavioral parameters in mice.     

Acute exposure to the vinyl chalcogenide 3‐methyl‐1‐phenyl‐2‐(phenylseleno)oct‐2‐en‐1‐one induces oxidative stress in different brain area of rats

The mechanisms that lead to the onset of organoselenium intoxication are still poorly understood. Therefore, in the present study, we investigated the effect of acute administration of 3‐methyl‐1‐phenyl‐2‐(phenylseleno)oct‐2‐en‐1‐one on some parameters of oxidative stress and on the activity of creatine kinase (CK) in different brain areas and on the behaviour in the open field test of 90‐day‐old male rats. Animals (n = 10/group) were treated intraperitoneally with a single dose of the organoselenium (125, 250 or 500 µg kg^?1), and after 1 h of the drug administration, they were exposed to the open field test, and behaviour parameters were recorded. Immediately after they were euthanized, cerebral cortex, hippocampus and cerebellum were dissected for measurement of thiobarbituric acid reactive substances (TBARS), carbonyl, sulfhydryl, catalase (CAT), superoxide dismutase (SOD) and CK activity. Our results showed that the dose of 500 µg kg^?1 of the organoselenium increased the locomotion and rearing behaviours in the open field test. Moreover, the organochalcogen enhanced TBARS in the cerebral cortex and cerebellum and increased the oxidation of proteins (carbonyl) only in the cerebral cortex. Sulfhydryl content was reduced in all brain areas, CAT activity enhanced in the hippocampus and reduced in the cerebellum and SOD activity increased in all brain structures. The organoselenium also inhibited CK activity in the cerebral cortex. Therefore, changes in motor behaviour, redox state and energy homeostasis in rats treated acutely with organoselenium support the hypotheses that the brain is a potential target for the organochalcogen action. Copyright © 2014 John Wiley & Sons, Ltd.     

Novel ETV6‐RUNX1 Mouse Model to Study the Role of ELF‐MF in Childhood B‐Acute Lymphoblastic Leukemia: a Pilot Study

Exposure to extremely low‐frequency magnetic fields (ELF‐MFs) has been classified by the International Agency for Research on Cancer (IARC) as “possibly carcinogenic to humans,” based on limited scientific evidence concerning childhood leukemia. This assessment emphasized the lack of appropriate animal models recapitulating the natural history of this disease. Childhood B‐cell acute lymphoblastic leukemia (B‐ALL) is the result of complex interactions between genetic susceptibility and exposure to exogenous agents. The most common chromosomal alteration is the ETV6‐RUNX1 fusion gene, which confers a low risk of developing the malignancy by originating a preleukemic clone requiring secondary hits for full‐blown disease to appear. To develop potential prophylactic interventions, we need to identify the environmental triggers of the second hit. Recently, we generated a B‐ALL mouse model of the human ETV6‐RUNX1⁺ preleukemic state. Here, we present the results from the ARIMMORA pilot study, obtained by exposing 34 Sca1‐ETV6‐RUNX1 mice (vs. 27 unexposed) to a 50 Hz magnetic field of 1.5 mT with both fundamental and harmonic content, with an on/off cycle of 10 min/5 min, for 20 h/day, from conception until 3 months of age. Mice were monitored until 2 years of age and peripheral blood was periodically analyzed by flow cytometry. One of the exposed mice developed B‐ALL while none of the non‐exposed did. Although the results are statistically non‐significant due to the limited number of mice used in this pilot experiment, overall, the results show that the newly developed Sca1‐ETV6‐RUNX1 mouse can be successfully used for ELF‐MF exposure studies about the etiology of childhood B‐ALL. Bioelectromagnetics. 2019;40:343–353. © 2019 Bioelectromagnetics Society.