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Exposure Groups (exposure + groups)
Selected AbstractsSublethal effects of methylmercury on fecal metabolites of testosterone, estradiol, and corticosterone in captive juvenile white ibises (Eudocimus albus),ENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 5 2009Evan M. Adams Abstract Methylmercury (MeHg) is a globally distributed neurotoxin, endocrine disruptor, and teratogen, and its effects on birds are poorly understood, especially within an environmentally relevant exposure range. In an effort to understand the potential causal relationship between MeHg exposure and endocrine development, we established four dietary exposure groups (0 [control], 0.05, 0.1, and 0.3 mg/kg wet wt/d of MeHg) of postfledging white ibises (Eudocimus albus) in a divided, free-flight aviary that spanned the estimated range of environmental exposure for this species. Fecal samples were collected from individually identified ibises over six months in 2005 and processed for hormone evaluation. Significant sex-related differences in fecal estradiol concentrations, though unpredicted in direction, suggest that this steroid could be related to juvenile development in this species. Using repeated-measures general linear models, we tested a set of candidate models to explain variation in endocrine expression. We found that MeHg exposure led to significant differences in fecal estradiol concentrations between the control and medium-dose groups, whereas differences in fecal corticosterone concentrations were observed between the control and both the low- and high-dose groups. These results suggest highly nonlinear dose-response patterns for MeHg. Many endocrine-disrupting contaminants are theorized to affect multiple endpoints in a nonlinear manner, making results difficult to interpret using a traditional toxicological approach. The evidence presented here suggests that endocrine effects of MeHg exposure could behave similarly. [source] Aquatic macroinvertebrates in the altes land, an intensely used orchard region in Germany: Correlation between community structure and potential for pesticide exposureENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 12 2006Christoph Schäfers Abstract To assess the impact of pesticides on aquatic organisms under realistic worst-case conditions, a macroinvertebrate community of small ditches was sampled at 40 sites of the orchard region Altes Land near Hamburg, Germany. To differentiate between pesticide impact and other variables, the ditches selected for sampling were located at different distances along grassland, unused apple orchards, and orchards managed with integrated and/or organic crop protection methods. Samples of macroinvertebrates were taken on five dates over two years. In addition to biological data, water chemistry and structural parameters were measured. For each sampling site, a potential for exposure was calculated on the basis of the distance of the ditch to the nearest row of trees and the depth and width of the ditch. The neighborhood to either grassland or orchards turned out to have a larger impact on the macroinvertebrate community than the potential for exposure. Therefore, grassland sites were omitted from further evaluation. Remaining sites were grouped into low exposure (sites at unused orchards), medium exposure (distance of 3,5 m [track] between trees and ditch), and high exposure (trees close to the ditch, mean distance , 1.5 m). Principal response curves showed differences in community structure between the three exposure groups over time. Whereas for sites from the high exposure group significant differences from low exposure was observed in all seasons, significant differences between low and medium were observed only occasionally. Effects were less pronounced in samples taken at springtime before the starting pesticide applications, suggesting some community recovery. Species richness was negatively correlated to exposure potential. Isopoda, Eulamellibranchiata, and insects, especially Ephemeroptera, showed a high negative correlation with the potential for pesticide exposure, suggesting that these taxa are sensitive to the pesticide use in the orchards. [source] A simulation study comparing different experimental designs for estimating uptake and elimination ratesENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 1 2006Bryan R. Bell Abstract The design of ecotoxicological studies requires decisions about the number and spacing of exposure groups tested, the number of replications, the spacing of sampling times, the duration of the study, and other considerations. For example, geometric spacing of sampling times or toxicant concentrations is often used as a default design. Optimal design methods in statistics can suggest alternative spacing of sampling times that yield more precise estimates of regression coefficients. In this study, we use a computer simulation to explore the impact of the spacing of sampling times and other factors on the estimation of uptake and elimination rate constants in an experiment addressing the bioaccumulation of a contaminant. Careful selection of sampling times can result in smaller standard errors for the parameter estimates, thereby allowing the construction of smaller, more precise confidence intervals. Thus, the effort invested in constructing an optimal experimental design may result in more precise inference or in a reduction of replications in an experimental design. [source] Application of an adjusted ,2 statistic to site-specific data in observational dental studiesJOURNAL OF CLINICAL PERIODONTOLOGY, Issue 1 2002Chul Ahn Abstract Background: When a binary response is observed on teeth from each subject belonging to 2 or more exposure groups, application of the usual Pearson ,2 tests is invalid, since such responses within the same subject are not independent. Consequently, special statistical methods are needed to control for the correlation among teeth (sites) within the same subject. A simple adjustment to the Pearson ,2 statistic has been proposed for comparing proportions in site-specific data. However, the required assumptions for this statistic have not yet been thoroughly addressed. These assumptions are guaranteed to hold in experimental comparisons, but may be violated in some observational studies. Method: We investigate the conditions under which the adjusted ,2 statistic is valid and examine the performance of the adjusted ,2 statistic when these conditions are violated. Results: Our simulation study shows that the adjusted ,2 statistic generally produces good empirical type I errors under the assumption of a common intracluster correlation coefficient. Even if the intracluster correlations are different, the adjusted statistic performs well when the groups have equal numbers of clusters (subjects). Conclusion: The discussion is illustrated using an observational study of caries on the roots of teeth. Zusammenfassung Hintergründe: Wenn eine binäre Antwort auf Zähne von jedem Subjekt, das zu 2 oder mehreren experimentellen Gruppen gehört, benutzt wird, ist die Anwendung des gewöhnlich genutzten Pearson ,2 Testes nicht zulässig, da solche Antworten innerhalb des selben Subjektes nicht unabhängig sind. In der Konsequent werden spezielle statistische Methoden gebraucht, um die Korrelation unter den Zähnen (Flächen) innerhalb desgleichen Subjektes zu kontrollieren. Eine simple Adjustierung zu der Pearson ,2 Statistik wurde vorgeschlagen, um die Verhältnisse der flächenspezifischen Daten zu vergleichen. Jedoch wurde sich der notwendigen Anwendung für diese Statistik noch nicht ausführlich gewidmet. Diese Anwendungen sind garantiert bei experimentellen Vergleichen anzuwenden, aber mögen in einigen beobachteten Studien verletzt werden. Methoden: Wir untersuchten die Bedingungen unter welchen der adjustierte ,2 Test richtig ist und prüften die Leistung des adjustierten ,2 Testes, wenn diese Bedingungen verletzt werden. Ergebnisse: Unsere Simulationsstudie zeigt, dass die adjustierte ,2 Statistik im Allgemeinen gute empirische Irrtümer vom Typ I erbringt unter der Anwendung eines gewöhnlichen Intracluster Korrelationskoeffizienten. Auche wenn die Intracluster-Korrelationen unterschiedlich sind, ist die adjustierte Statistik gut zu nutzen, wenn die Gruppen gleiche Nummern von Clustern haben (Subjekte). Schlußfolgerungen: Die Diskussion wird illustriert unter Nutzung einer beobachteten Studie von Wurzelkaries. Résumé Origine: Lorsqu'une réponse binaire est observée sur les dents de chaque sujet appartenant à 2 groupes ou plus, l'application du test habituel ,2 de Pearson n'est pas valable puisque de telles réponses pour le même sujet sont indépendante. En conséquence, des méthodes statistiques spéciales sont nécessaires pour contrôler les corrélation entre les dents (sites) pour le même sujet. Un simple ajustement de la statistique ,2 de Pearson a été proposée pour comparer les proportions pour les données spécifiques de sites. Cependant, les hypothèses requises pour cette statistique n'ont pas encore été consciencieusement émises. Ces hypothèses sont certifiées être valable pour les comparaisons experimentales, mais peuvent ne pas être respectées dans quelques études observationnelles. Méthode: Nous recherchons les conditions pour lesquelles la statistique ,2 ajustée est valable et examinons sa performance lorsque ces conditions ne sont pas respectées. Résultats: Notre étude simulée montre que la statistique ,2 ajustée produit généralement de bonnes érreurs empiriques de type 1 dans l'hypothèse d'un coéfficient de corrélation commun intra-groupe. Même si les corrélations intragroupes sont différentes, la statistique ,2 ajustée s'exécute bien quand les ensembles ont des nombres égaux de groupes (sujets). Conclusion: La discussion est illustrée par une étude observationnelle des caries radiculaires. [source] Parent Ratings of Behavior in Children with Heavy Prenatal Alcohol Exposure and IQ-Matched ControlsALCOHOLISM, Issue 2 2000Sarah N. Mattson Background: Behavioral disturbances are well documented in children with heavy prenatal alcohol exposure. However, the degree to which these disturbances are related to factors other than alcohol, such as general intellectual functioning or socioeconomic status, is not known. Methods: Using the Child Behavior Checklist, parent-rated behaviors of children with histories of heavy prenatal alcohol exposure were compared with those of a control group matched by age, sex, socioeconomic status, ethnicity, and verbal IQ score. Using this same questionnaire, children with fetal alcohol syndrome were compared with children with heavy prenatal alcohol exposure that did not meet the criteria for fetal alcohol syndrome classification. Results: Data were analyzed by multivariate analyses of covariance. In the comparison of children with and without a history of prenatal alcohol exposure, significant differences were found on the competence, problem, and summary scales (all p < 0.05). For the secondary comparison between the fetal alcohol syndrome and the heavy prenatal alcohol exposure groups, there were no significant differences on any of the scales (all p > 0.10). Conclusions: These results suggest that prenatal alcohol exposure results in the significant and profound impairment of parent-rated behaviors and that these deficits are not explained entirely by the presence or absence of facial dysmorphology, general intellectual functioning, or demographic factors. [source] Meta-analysis: the use of non-steroidal anti-inflammatory drugs and pancreatic cancer risk for different exposure categoriesALIMENTARY PHARMACOLOGY & THERAPEUTICS, Issue 8 2007G. CAPURSO Summary Background, A better understanding of predictors of risk for pancreatic ductal adenocarcinoma (PDAC) could inform preventive efforts against this lethal cancer. While aspirin (ASA) and non-steroidal anti-inflammatory drugs (NSAIDS) might protect against several gastrointestinal cancers, their role in the development of PDAC remains unclear. Aim, To conduct a systematic review and meta-analysis on the relation between ASA/NSAIDs exposure and the risk of PDAC. Methods, We searched Pubmed, Embase, Scopus, Cochrane database of systematic reviews and reference lists of identified papers and included observational (cohort or case-control) studies and randomized controlled trials examining exposure to ASA and/or NSAIDs and the incidence or mortality of PDAC. We defined three categories (low, intermediate, high), based on exposure duration and dose. Results, Eight studies fulfilled our inclusion criteria (four cohort, three case controls, and one randomized controlled trial studies) enrolling 6301 patients between 1971,2004; all but one study took place in the US. The pooled OR were 0.99 (0.83,1.19), 1.11 (0.84,1.47) and 1.09 (0.67,1.75) in the low, intermediate and high exposure groups respectively, with considerable heterogeneity (I2 ranging 60,86%). Sensitivity analysis by ASA use only, study design or sex did not reveal additional important information. Conclusions, This study did not show an association between ASA/NSAIDs and PDAC. The large baseline exposure in controls in North-America may have obscured an association. There is need for additional studies, especially in Europe, to clarify this issue. [source] Dupuytren's disease: Personal factors and occupational exposureAMERICAN JOURNAL OF INDUSTRIAL MEDICINE, Issue 1 2008Gérard Lucas Abstract Background The etiology of Dupuytren's disease is unknown, and the role of occupational exposure is still debated. Our objective was to study the association between occupational exposures, personal risk factors and Dupuytren's disease. Methods In this cross-sectional survey, nine occupational physicians performed clinical examinations, focused on Dupuytren's disease, of 2,406 French male civil servants employed at the Equipment Ministry in 1998 and interviewed them about medical history, leisure manual exposure and occupational biomechanical exposure to vibrations and manual work. A cumulative occupational exposure score was defined, with three levels of exposure. Results Dupuytren's disease was diagnosed in 212 men (8.8%). The occupational exposure score was significantly higher in this group of cases than in the rest of the sample (377 (SD280) vs. 223 (SD250), respectively; P,<,0.0001). Occupational exposure was associated with Dupuytren's disease (adjusted Odds Ratio,=,2.20 [1.39,3.45] for the intermediate and 3.10 [1.99,4.84] for the high exposure groups), with adjustment for age, leisure physical activities, alcohol consumption (,5 servings per day), history of diabetes, epilepsy, hand trauma, and familial history of Dupuytren's disease. Conclusion Manual work exposure was associated with Dupuytren's disease after adjustment for personal risk factors. Longitudinal studies are needed to confirm these results. Am. J. Ind. Med. 51:9,15, 2008. © 2007 Wiley-Liss, Inc. [source] Smoking behavior in trucking industry workersAMERICAN JOURNAL OF INDUSTRIAL MEDICINE, Issue 12 2006MSPH, Nitin B. Jain MD Abstract Background In retrospective occupational studies, the degree of confounding by smoking depends on variation in smoking among job-related exposure groups. We assessed the relationship between job title and smoking behavior as part of a study on occupational exposures and lung cancer. Methods A questionnaire on smoking was mailed to a sample of 11,986 trucking industry workers. Company records were used to gather other relevant information. Results The response rate was 40.5%. Among white males, the age-adjusted prevalence of ever smoking was highest among longhaul truck drivers (67%) and lowest among clerks (44%). Smoking rates among workers with other job titles were similar. Conclusions Our results will be used to adjust for the differences in smoking among job-related exposure groups when assessing the association between particulate matter exposure and lung cancer mortality. Our study also suggests that an assessment of methods to control for smoking should be considered in the design of retrospective occupational health studies. Am. J. Ind. Med. 2006. © 2006 Wiley-Liss, Inc. [source] Vibration exposure and disease in a shipyard: A 13-year revisitAMERICAN JOURNAL OF INDUSTRIAL MEDICINE, Issue 6 2004Martin Cherniack MD Abstract Background In a 1988 study of shipyard workers, a progressive association was observed between cumulative exposure to vibration and the vascular and neurological symptoms of the hand-arm vibration syndrome (HAVS). In 2001, after a decade of exposure reduction and ageing of the workforce, a second study at the same site was initiated. Methods In 2001, 214 subjects were selected; they represented four current weekly vibration exposure time intervals,0 hr, >0,<,5 hr, ,5,<,20 hr, ,20 hr. The 1988 and 2000 cross-sectional populations were compared on the basis of exposure duration and current symptoms. Results In 2001, the study population was 9.6 years older than the 1988 group. Current weekly exposure hours were similar in the low and medium exposure groups 2001 and 1988, but exposure was reduced by an average of 9.7 hr per week in the highest exposure group (,20 hr) in 2001. Symptom severity was regressed polychotomously on estimated exposure (log cumulative hours); the OR was weaker in 2001 than in 1988 for sensorineural symptoms,1.44 [CI 1.04,1.98] versus 2.35 [CI 1.48,3.73]. This was also true for vascular symptoms,1.70 [CI 1.06,2.71] versus 3.99 [CI 2.27,7.01]. Vascular symptoms were more prevalent in the highest lifetime vibration exposure group in 1988 (68.7 vs. 43.2% in 2001); sensorineural symptoms were more prevalent in the least vibration exposed group in 2001 (52.6 vs. 20.7% in 1988). Conclusions The prevalence of vascular symptoms associated with cumulative vibratory exposure was significantly greater in 1988, but neurological symptoms were more common at lower exposure levels in 2001. The presumption that reducing exposure duration alone is sufficient, in the absence of change in vibration magnitude, is not supported by the results of this study. Am. J. Ind. Med. 45:500,512, 2004. © 2004 Wiley-Liss, Inc. [source] Individual and combined impacts of biomechanical and work organization factors in work-related musculoskeletal symptoms,,AMERICAN JOURNAL OF INDUSTRIAL MEDICINE, Issue 5 2003Grant D. Huang MPH Abstract Background Investigations of work-related low back (LB) and upper extremity (UE) disorders have increasingly utilized multivariable models that include biomechanical/physical and work organization factors. However, the nature of any interactive effects is not well understood. Methods Using questionnaires, high and low exposure groups for biomechanical/physical factors, cognitive demands, cognitive processing, interpersonal demands, participatory management, skill discretion, and time pressure for 289 individuals (U.S. Marines) were identified. Musculoskeletal symptom status was also determined by questionnaire. Individual and biomechanical,psychosocial combinations were examined in adjusted multivariable logistic regression analyses. Results Time pressure was associated with both LB and UE symptoms (odds ratio(s) (OR) range,=,2.13,3.09), while higher biomechanical exposures were risk factors for LB symptoms (OR,=,2.07; 95% confidence intervals (CI): 1.00,4.35) and concurrent LB and UE symptoms (OR,=,2.80; CI: 1.35,5.83). Greater risks for concurrent LB and UE symptoms were indicated for combinations involving higher biomechanical exposure and: time pressure (OR,=,2.21; CI: 1.19,4.10); cognitive demands (OR,=,2.25; CI: 1.23,4.09); cognitive processing (OR,=,2.08; CI: 1.16,3.75); interpersonal demands (OR,=,2.44; CI: 1.35,4.41); participatory management (OR,=,2.50; CI: 1.30,4.81). Results did not suggest any interaction between biomechanical and work organization factors. Conclusions While no synergism was indicated, the present findings emphasize the need to consider both biomechanical factors and specific work organization factors, particularly time pressure, in reducing musculoskeletal-related morbidity. Am. J. Ind. Med. 43:495,506, 2003. Published 2003 Wiley-Liss, Inc. [source] Non-malignant asbestos-related diseases in Brazilian asbestos-cement workersAMERICAN JOURNAL OF INDUSTRIAL MEDICINE, Issue 3 2001E. Algranti MD Abstract Background Production of asbestos-cement products in Brazil started in the 1940s, peaked in the 60,70s and is still an active industry. This study was designed to assess the non-malignant effects of asbestos exposure in the asbestos-cement industry in Brazil. Methods A group of 828 former asbestos-cement workers enrolled in a cross-sectional and cohort study of respiratory morbidity, submitted to a detailed occupational history, respiratory symptoms questionnaire, spirometry, PA chest x-ray, and high resolution computed chest tomography (HRCT). Asbestos exposure was assessed by years of exposure, cumulative exposure (a semi-quantitative method), and latency time from first exposure. Asbestosis and pleural thickening were assessed according to HRCT criteria. Results Asbestosis was present in 74 (8.9%) and pleural thickening in 246 (29.7%). Using the HRCT as the "best available evidence", it was shown that were more false negatives than false positives in the x-ray readings for parenchymal (21.6% false negatives, 4.2% false positives) and pleural (26.0% false negatives, 14.4% false positives) diseases due to asbestos. Latency time from first exposure was the best predictor for both asbestosis and pleural thickening. Subjects in the higher exposure groups presented lower levels of lung function. Obstructive defects were significantly related to smoking, shortness of breath, body mass index, and age, whereas restrictive defects were related to asbestosis, shortness of breath, and latency time. Chronic bronchitis increased with latency time in the three smoking groups and was significantly related to pleural thickening (OR 1.56 (1.00,2.42)). Shortness of breath was significantly associated with body mass index and pleural thickening (OR 1.30 (1.24,2.09)). Conclusions Pleural thickening and asbestosis showed a significant association with latency time and exposure. FVC and FEV1 decreased across increasing profusion with an added effect of pleural thickening. There was a significant and independent effect of exposure on lower levels of FVC and FEV1. Obstructive defects were mainly related to smoking and restriction to asbestosis. Dust exposure and smoking were synergistic in increasing chronic bronchitis and shortness of breath report. Shortness of breath report was also related to pleural thickening and higher body mass index. Am. J. Ind. Med. 40:240,254, 2001. © 2001 Wiley-Liss, Inc. [source] Use of QuantiFERON® -TB Gold to investigate tuberculosis contacts in a high schoolRESPIROLOGY, Issue 1 2007Kazue HIGUCHI Background and objective: QuantiFERON® -TB Gold (QFT-G) was employed in a contact investigation in a high school to evaluate its performance in adolescents. Methods: Students of the same school grade as the index case were screened with tuberculin skin test (TST) and CXR examination as an initial contact investigation. QFT-G was performed for students demonstrating a positive TST (erythema larger than 30 mm). Results: Of 349 students whose TST was completed, 95 had positive TST responses, although the distribution of TST responses was similar for both high and low exposure groups. In contrast, only four of the 88 TST-positive students tested with QFT-G were positive by this test, and three of these were from the high exposure group. Chemoprophylaxis was provided to only those four QFT-G-positive students. Follow up of the 91 students who were TST-positive, but QFT-G-negative (or not tested), for more than 3.5 years revealed that none have developed active tuberculosis. Conclusions: QFT-G appears more specific than TST as contacts with positive TST and negative QFT-G responses were not offered prophylaxis and none developed tuberculosis during 3.5 years of follow up. The replacement of TST with QFT-G, or perhaps combined use of TST and QFT-G, may be more useful in diagnosing true infection and thus reducing the number of subjects indicated for chemoprophylaxis. [source] 1950,MHz IMT-2000 field does not activate microglial cells in vitroBIOELECTROMAGNETICS, Issue 2 2010Hideki Hirose Abstract Given the widespread use of the cellular phone today, investigation of potential biological effects of radiofrequency (RF) fields has become increasingly important. In particular, much research has been conducted on RF effects on brain function. To examine any biological effects on the central nervous system (CNS) induced by 1950,MHz modulation signals, which are controlled by the International Mobile Telecommunication-2000 (IMT-2000) cellular system, we investigated the effect of RF fields on microglial cells in the brain. We assessed functional changes in microglial cells by examining changes in immune reaction-related molecule expression and cytokine production after exposure to a 1950,MHz Wideband Code Division Multiple Access (W-CDMA) RF field, at specific absorption rates (SARs) of 0.2, 0.8, and 2.0,W/kg. Primary microglial cell cultures prepared from neonatal rats were subjected to an RF or sham field for 2,h. Assay samples obtained 24 and 72,h after exposure were processed in a blind manner. Results showed that the percentage of cells positive for major histocompatibility complex (MHC) class II, which is the most common marker for activated microglial cells, was similar between cells exposed to W-CDMA radiation and sham-exposed controls. No statistically significant differences were observed between any of the RF field exposure groups and the sham-exposed controls in percentage of MHC class II positive cells. Further, no remarkable differences in the production of tumor necrosis factor-, (TNF-,), interleukin-1, (IL-1,), and interleukin-6 (IL-6) were observed between the test groups exposed to W-CDMA signal and the sham-exposed negative controls. These findings suggest that exposure to RF fields up to 2,W/kg does not activate microglial cells in vitro. Bioelectromagnetics 31:104,112, 2010. © 2009 Wiley-Liss, Inc. [source] Lack of a co-promotion effect of 60,Hz circularly polarized magnetic fields on spontaneous development of lymphoma in AKR miceBIOELECTROMAGNETICS, Issue 2 2010Moon-Koo Chung Abstract The present study was conducted to investigate the possible effect of 60,Hz circularly polarized magnetic fields (MFs) as promoters of genetically initiated lymphoma in AKR mice. One hundred sixty female animals were divided into four different groups. They were exposed to four different intensities of circularly polarized MFs. Animals received exposure to 60,Hz circularly polarized MF at field strengths (rms-value) of 0,µT (sham control, T1, Group I), 5,µT(T2, Group II), 83.3,µT (T3, Group III), or 500,µT(T4, Group IV), for 21,h/day from the age of 4,6 weeks to the age of 44,46 weeks. There were no exposure-related changes in mean survival time, clinical signs, body weights, hematological values, micronucleus assay, gene expression arrays, analysis of apoptosis, and necropsy findings. At histopathological examination, lymphoma was seen in all the groups. The tumor incidence was 31/40(78%), 30/40(75%), 32/40(80%), and 31/40(78%) in sham control, 5, 83.3, and 500,µT groups, respectively. However, there were no differences in the tumor incidence between the sham control (T1) and circularly polarized MF exposure groups (T2,T4). In conclusion, there was no evidence that exposure to 60,Hz circularly polarized MF strengths up to 500,µT promoted lymphoma in AKR mice. Bioelectromagnetics 31:130,139, 2010. © 2009 Wiley-Liss, Inc. [source] Effects of gestational exposure to 1.95-GHz W-CDMA signals for IMT-2000 cellular phones: Lack of embryotoxicity and teratogenicity in ratsBIOELECTROMAGNETICS, Issue 3 2009Kumiko Ogawa Abstract The present study was designed to evaluate whether gestational exposure to an EMF targeting the head region, similar to that from cellular phones, might affect embryogenesis in rats. A 1.95-GHz wide-band code division multiple access (W-CDMA) signal, which is one applied for the International Mobile Telecommunication 2000 (IMT-2000) system and used for the freedom of mobile multimedia access (FOMA), was employed for exposure to the heads of four groups of pregnant CD(SD) IGS rats (20 per group) for gestational days 7,17. The exposure was performed for 90 min/day in the morning. The spatial average specific absorption rate (SAR) for individual brains was designed to be 0.67 and 2.0 W/kg with peak brain SARs of 3.1 and 7.0 W/kg for low (group 3) and high (group 4) exposures, respectively, and a whole-body average SAR less than 0.4 W/kg so as not to cause thermal effects due to temperature elevation. Control and sham exposure groups were also included. At gestational day 20, all dams were killed and fetuses were taken out by cesarean section. There were no differences in maternal body weight gain. No adverse effects of EMF exposure were observed on any reproductive and embryotoxic parameters such as number of live (243,271 fetuses), dead or resorbed embryos, placental weights, sex ratios, weights or external, visceral or skeletal abnormalities of live fetuses. Bioelectromagnetics 30:205,212, 2009. © 2008 Wiley-Liss, Inc. [source] | |||||||||||||