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Query: UNIPROT:Q86TM3 (cage)
 29,987 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Previous research has shown that SAR "hotspots" are induced within the laboratory rat and that the resulting thermal hotspots are not entirely dissipated by bloodflow. Two experiments were conducted to determine if hotspot formation in the body and tail of the rat, which is radiation frequency specific, would have behavioral consequences. In the first experiment rats were placed in a plexiglas cage one side of which, when occupied by the rat, commenced microwave radiation exposure; occupancy of the other side terminated exposure. Groups of rats were tested during a baseline period to determine the naturally preferred side of the cage. Subsequent exposure to 360-MHz, 700-MHz or 2450-MHz microwave radiation was made contingent on preferred-side occupancy. A significant reduction in occupancy of the preferred side of the cage, and hence, microwaves subsequently occurred. Reduced exposure to 360-MHz and 2450-MHz microwaves at 1, 2, 6 and 10 W/kg were significantly different from 700-MHz microwaves. In the second experiment semichronic exposures revealed the threshold for reduced exposure of 2450-MHz microwaves to be located between whole-body SAR's of 2.1 and 2.8 W/kg.
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PMID:Reduced exposure to microwave radiation by rats: frequency specific effects. 334 73

Pregnant squirrel monkeys were exposed to 2450-MHz (CW) microwaves at an equivalent power density of 10 mW/cm2 (SAR 3.4 mW/g) for three hours daily in a cavity-cage module. The exposure began when pregnancy was determined by a hormonal method, and continued through of offspring's first 9.5 months. After irradiation, the brain of the offspring were fixed with formaldehyde, and the inferior vermis of each cerebella was removed and processed for histologic observations. Purkinje cell density in the uvula was determined in sagittal serial section. There was no significant difference between control and experimental animals in the number of Purkinje cells per mm of Purkinje cell line (linear density), as well as in the density of Purkinje cells in the Purkinje cell layer.
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PMID:Effect of nonionizing radiation on the Purkinje cells of the uvula in squirrel monkey cerebellum. 730 20

Exposure of humans and rodents to radiofrequency (RF) cell phone fields has been reported to alter a number of stress- related parameters. To study this potential relationship in more detail, tube-restrained immobilized Fischer 344 rats were exposed in the near field in a dose-dependent manner to pulse-modulated (11 packets/s) digital cell phone microwave fields at 1.6 GHz in accordance with the Iridium protocol. Core body temperatures, plasma levels of the stress-induced hormones adrenocorticotrophic hormone (ACTH) and corticosterone, and brain levels of ornithine decarboxylase (Odc), Fos and Jun mRNAs were measured as potential markers of stress responses mediated by RF radiation. We tested the effects of the loose-tube immobilization with and without prior conditioning throughout a 2-h period (required for near-field head exposure to RF fields), on core body temperature, plasma ACTH and corticosteroids. Core body temperature increased transiently (+/-0.3 degrees C) during the initial 30 min of loose-tube restraint in conditioned animals. When conditioned/tube-trained animals were followed as a function of time after immobilization, both the ACTH and corticosterone levels were increased by nearly 10-fold. For example, within 2-3 min, ACTH increased to 83.2 +/- 31.0 pg/dl, compared to 28.1 +/- 7.7 pg/dl for cage controls, reaching a maximum at 15-30 min (254.6 +/- 46.8 pg/dl) before returning to near resting levels by 120 min (31.2 +/- 10.2 pg/dl). However, when non-tube-trained animals were submitted to loose-tube immobilization, these animals demonstrated significantly higher (3-10-fold greater) hormone levels at 120 min than their tube-trained counterparts (313.5 +/- 54.8 compared to 31.2 +/- 10.2 pg/dl; corticosterone, 12.2 +/- 6.2 microg/dl compared to 37.1 +/- 6.4 microg/dl). Hormone levels in exposed animals were also compared to those in swim-stressed animals. Swimming stress also resulted in marked elevation in both ACTH and corticosterone levels, which were 10-20 fold higher (541.8 compared to 27.2-59.1 pg/dl for ACTH) and 2-5 fold higher (45.7 compared to 8.4- 20.0 microg/dl for corticosteroids) than the cage control animals. Three time-averaged brain SAR levels of 0.16, 1.6 and 5 W/ kg were tested in a single 2-h RF-field exposure to the Iridium cell phone field. When RF-exposed and sham-exposed (immobilized) animals were compared, no differences were seen in core body temperature, corticosterone or ACTH that could be attributed to near-field RF radiation. Levels of Odc, Fos and Jun mRNA were also monitored in brains of animals exposed to the RF field for 2 h, and they showed no differences from sham-exposed (loose-tube immobilized) animals that were due to RF-field exposure. These data suggest that a significant stress response, indicated by a transient increase in core body temperature, ACTH and corticosterone, occurred in animals placed in even the mild loose-tube immobilization required for near-field RF exposure employed here and in our other studies. Failure to adequately characterize and control this immobilization response with appropriate cage control animals, as described previously, could significantly mask any potential effects mediated by the RF field on these and other stress-related parameters. We conclude that the pulse-modulated digital Iridium RF field at SARs up to 5 W/kg is incapable of altering these stress-related responses. This conclusion is further supported by our use of an RF-field exposure apparatus that minimized immobilization stress; the use of conditioned/tube-trained animals and the measurement of hormonal and molecular markers after 2 h RF-field exposure when the stress-mediated effects were complete further support our conclusion.
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PMID:Effect of immobilization and concurrent exposure to a pulse-modulated microwave field on core body temperature, plasma ACTH and corticosteroid, and brain ornithine decarboxylase, Fos and Jun mRNA. 1126 Jun 60

In this study, a method is proposed for MRI of the lumen of metallic vascular implants, like stents or vena cava filters. The method is based on the reduction of artifacts caused by flow, susceptibility, and RF eddy currents. Whereas both flow artifacts and susceptibility artifacts are well understood and documented, RF artifacts are not. Therefore, the present study comprises an in-depth theoretical explanation of the factors governing the severity of these RF artifacts. It is explained that the RF caging inside cage-like implants is caused by disturbances of the send and receive sensitivities due to coupling between the loops in the implant and the MR scanner's send and receive coils. A scaled excitation angle model describing the behavior of the signal intensity inside the implants as a function of the applied nominal excitation angle is introduced. This theoretical model was validated in phantom experiments. Reduced signal from within implants due to the caging problem could be restored by increasing the applied RF power in the excitation pulse, without exceeding the generally accepted SAR safety limits. The method was tested in vitro and in vivo in a pig model and allowed adequate depiction of the interior of a nitinol stent and that of a vena cava filter in contrast-enhanced MR angiograms. Magn Reson Med 47:171-180, 2002.
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PMID:Improved lumen visualization in metallic vascular implants by reducing RF artifacts. 1175 56

The effects of acute exposure to GSM-900 microwaves (900 MHz, 217 Hz pulse modulation) on the clinical parameters of the acute experimental allergic encephalomyelitis (EAE) model in rats were investigated in two independent experiments: rats were either habituated or nonhabituated to the exposure restrainers. EAE was induced with a mixture of myelin basic protein and Mycobacterium tuberculosis. Female Lewis rats were divided into cage control, sham exposed, and two groups exposed either at 1.5 or 6.0 W/kg local specific absorption rate (SAR averaged over the brain) using a loop antenna placed over their heads. There was no effect of a 21 day exposure (2 h/day) on the onset, duration, and termination of the EAE crisis.
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PMID:Effects of GSM-900 microwaves on the experimental allergic encephalomyelitis (EAE) rat model of multiple sclerosis. 1266 5

The total synthesis of 1-O-methyllateriflorone (2) is described. The construction of the cage-like domain of the molecule involved a biomimetic Claisen/Diels-Alder cascade, whereas the novel spiroxalactone framework was generated by an intramolecular Michael reaction within precursor 16a involving the carboxylate residue as the nucleophile. This finding might bear on the biosynthetic pathway by which nature forms lateriflorone. Described herein is also an interesting cascade sequence involving facile 6 pi electrocyclizations which leads to complex benzopyran systems. The biological evaluation of a small library of lateriflorone analogues and related systems establishing the first SAR within this class of compounds is also included. Among the most active compounds against tumor cells are 2, 16b, 56, 58, and 59.
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PMID:Biomimetically inspired total synthesis and structure activity relationships of 1-O-methyllateriflorone. 6 pi electrocyclizations in organic synthesis. 1511 21

The purpose of this study was to determine whether long-term exposure to a 1.6 GHz radiofrequency (RF) field would affect the incidence of cancer in Fischer 344 rats. Thirty-six timed-pregnant rats were randomly assigned to each of three treatment groups: two groups exposed to a far-field RF Iridium signal and a third group that was sham exposed. Exposures were chosen such that the brain SAR in the fetuses was 0.16 W/kg. Whole-body far-field exposures were initiated at 19 days of gestation and continued at 2 h/day, 7 days/week for dams and pups after parturition until weaning (approximately 23 days old). The offspring (700) of these dams were selected, 90 males and 90 females for each near-field treatment group, with SAR levels in the brain calculated to be as follows: (1) 1.6 W/kg, (2) 0.16 W/kg and (3) near-field sham controls, with an additional 80 males and 80 females as shelf controls. Confining, head-first, near-field exposures of 2 h/day, 5 days/week were initiated when the offspring were 36 +/- 1 days old and continued until the rats were 2 years old. No statistically significant differences were observed among treatment groups for number of live pups/litter, survival index, and weaning weights, nor were there differences in clinical signs or neoplastic lesions among the treatment groups. The percentages of animals surviving at the end of the near-field exposure were not different among the male groups. In females a significant decrease in survival time was observed for the cage control group.
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PMID:Two-year chronic bioassay study of rats exposed to a 1.6 GHz radiofrequency signal. 1538 48

There are public concerns regarding possible carcinogenic or cancer-promoting effects of electromagnetic fields (EMFs) from mobile phones and base stations. The objective of the present study was to investigate whether chronic exposure to EMFs of the UMTS (Universal Mobile Telecommunication System) influences the development of lymphoma in a lymphoma animal model, the AKR/J mouse. Unrestrained mice were chronically sham-exposed (n = 160) or exposed (n = 160) in identical exposure systems (radial waveguides) to a generic UMTS test signal (24 h per day, 7 days per week, 0.4 W/kg SAR). Additionally, 30 animals were kept as cage controls. Animals were checked visually each day and were weighed and palpated weekly to detect swollen lymph nodes. Starting at the age of 6 months, blood samples were taken from the tail every 2 weeks to perform differential leukocyte counts and to measure the hematocrit. Visibly diseased animals or those older than 43 weeks were killed humanely, and tissue slices were examined for metastatic infiltrations and lymphoma type. The study was performed in a blinded way. Cage control animals had a significantly lower growth rate than those kept in the radial waveguides. The number of ill animals, the mean survival time, and the severity code of the disease did not differ between the experimental groups. Therefore, the data show no negative effects from exposure and corroborate earlier findings in AKR/J mice exposed to GSM EMF (Sommer et al., BMC Cancer 4, 77-90, 2004).
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PMID:Lymphoma development in mice chronically exposed to UMTS-modulated radiofrequency electromagnetic fields. 1772

The aim of the study was to detect whether long-term exposure to "902-MHz GSM-type Wireless Communication Signals" ("radio-frequency (RF)-exposure") would affect 7,12-dimethylbenz(a)anthracene (DMBA)-induced mammary tumours in female Sprague-Dawley rats. Five hundred female rats were each given a single oral dose of 17 mg DMBA per kg body weight (bw) at an age of 46-48 days. Three groups of 100 animals each were RF-exposed (902 MHz; crest factor 8; pulse width=0.57 ms) from the next day onwards to normal whole-body averaged doses (expressed as specific absorption rate, SAR) of 0.4, 1.3 or 4.0 W/kg bw (low/mid/high-dose group) for 4h/d, 5d/week, during 6 months. A sham-exposed and a cage-control group remained without RF-exposure (<<0.01 mW/kg). Animals were weekly weighed and palpated for mammary tumours; all mammary glands were examined histopathologically. There were several statistically significant differences between RF-exposed groups and the sham-exposed group, as follows: All RF-exposed groups had, at different times, significantly more palpable tissue masses. There were fewer animals with benign neoplasms, but more with malignant tumours in the high-dose group. In addition, there were more adenocarcinomas in the low-dose group, more malignant neoplasms in the low- and high-dose groups, more animals with adenocarcinomas in the high-dose group, and fewer animals with fibroadenomas in the low- and mid-dose groups. The cage-control group had, when compared with the sham-exposed group, statistically significantly more palpable tissue masses, more benign and also more malignant neoplasms. The cage-control group had in most aspects the highest incidence and malignancy of neoplasms among all groups. None of the above findings in RF-exposed animals produced a clear dose-response relation and the responses of the cage-control group were either similar to or stronger than those of any of the RF-exposed group. The significant differences between the sham-exposed animals and one or more RF-exposed groups may be interpreted as evidence of an effect of RF-exposure. In the context of the results of the cage-control group, in the light of controversial results reported in the literature, and given the fact that the DMBA-mammary tumour model is known to be prone to high variations in the results, it is the authors' opinion that the differences between the groups are rather incidental ones.
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PMID:Study on potential effects of "902-MHz GSM-type Wireless Communication Signals" on DMBA-induced mammary tumours in Sprague-Dawley rats. 1798 Oct 79

Considering the frequent use of mobile phones, we have directed attention to possible implications on cognitive functions. In this study we investigated in a rat model the long-term effects of protracted exposure to Global System for Mobile Communication-900 MHz (GSM-900) radiation. Out of a total of 56 rats, 32 were exposed for 2 h each week for 55 weeks to radio-frequency electromagnetic radiation at different SAR levels (0.6 and 60 mW/kg at the initiation of the experimental period) emitted by a (GSM-900) test phone. Sixteen animals were sham exposed and eight animals were cage controls, which never left the animal house. After this protracted exposure, GSM-900 exposed rats were compared to sham exposed controls. Effects on exploratory behaviour were evaluated in the open-field test, in which no difference was seen. Effects on cognitive functions were evaluated in the episodic-like memory test. In our study, GSM exposed rats had impaired memory for objects and their temporal order of presentation, compared to sham exposed controls (P = 0.02). Detecting the place in which an object was presented was not affected by GSM exposure. Our results suggest significantly reduced memory functions in rats after GSM microwave exposure (P = 0.02).
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PMID:Cognitive impairment in rats after long-term exposure to GSM-900 mobile phone radiation. 1941 13


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