Radio frequency electromagnetic field exposure in humans: Estimation of SAR distribution in the brain, effects on sleep and heart rate.

In two previous studies we demonstrated that radiofrequency electromagnetic fields (RF EMF) similar to those emitted by digital radiotelephone handsets affect brain physiology of healthy young subjects exposed to RF EMF (900 MHz; spatial peak specific absorption rate [SAR] 1 W/kg) either during sleep or during the waking period preceding sleep. In the first experiment, subjects were exposed intermittently during an 8 h nighttime sleep episode and in the second experiment, unilaterally for 30 min prior to a 3 h daytime sleep episode. Here we report an extended analysis of the two studies as well as the detailed dosimetry of the brain areas, including the assessment of the exposure variability and uncertainties. The latter enabled a more in depth analysis and discussion of the findings. Compared to the control condition with sham exposure, spectral power of the non-rapid eye movement sleep electroencephalogram (EEG) was initially increased in the 9-14 Hz range in both experiments. No topographical differences with respect to the effect of RF EMF exposure were observed in the two experiments. Even unilateral exposure during waking induced a similar effect in both hemispheres. Exposure during sleep reduced waking after sleep onset and affected heart rate variability. Exposure prior to sleep reduced heart rate during waking and stage 1 sleep. The lack of asymmetries in the effects on sleep EEG, independent of bi- or unilateral exposure of the cortex, may indicate involvement of subcortical bilateral projections to the cortex in the generation of brain function changes, especially since the exposure of the thalamus was similar in both experiments (approx. 0.1 W/kg)

Health-related quality of life: a retrospective study on local vs. microvascular reconstruction in patients with oral cancer

BackgroundNew medicinal and surgical oncological treatment strategies not only improve overall survival rates but continually increase the importance of Health-Related Quality of Life (HRQOL). The purpose of this retrospective cross-sectional study was to analyze HRQOL of patients with oral squamous cell carcinoma after ablative surgery and to evaluate predictive factors for HRQOL outcome.MethodsThe study included 88 patients with histologically confirmed oral squamous cell carcinoma of whom 42 had undergone local reconstruction (LR) and 46 microvascular reconstruction (MVR). During follow-up, all patients completed the University of Washington Quality of Life Questionnaire (UW-QOL) containing 12 targeted questions about the head and neck. Descriptive analyses were made for the tumor site, the T-stage, and adjuvant therapies. HRQOL was compared between the LR and the MVR group with parametric tests. Further analyses were impact of the tumor site, the T-status, and the time from surgery to survey on HRQOL. Statistics also included multivariate correlations and different interaction effects.ResultsHRQOL in the LR group was very good' with 84.313.7 and good' in the MVR group with 73.316.5 points. The physical domains swallowing (p=0.00), chewing (p=0.00), speech (p=0.01), taste (p=0.01), and pain (p=0.04) were significantly worse in the MVR group. An increase in the T-status had a significant negative effect on swallowing (p=0.01), chewing (p=0.01), speech (p=0.03), recreation (p=0.05), and shoulder (p=0.01) in both groups. Regarding the tumor site and subsequent loss of HRQOL, patients with squamous cell carcinoma on the floor of the mouth had significantly worse results in the categories pain (p=0.002), speech (p=0.002), swallowing (p=0.03), activity (p=0.02), and recreation (p=0.01) than patients with tumors in the buccal mucosa. Speech (p=0.03) and pain (p=0.01) had improved 1year after surgery.Conclusion Patients with flap reconstruction because of oral squamous cell carcinoma showed very good overall HRQOL. Outcomes for microvascular reconstruction were good, even in the case of larger defects. The T-status is a predictor for HRQOL. Swallowing, chewing, speaking, taste, and pain were the most important issues in our cohort. Implementing HRQOL questionnaires for the assessment of quality of life could further increase the treatment quality of patients with oral cancer

OSCC in Never-Smokers and Never-Drinkers Is Associated with Increased Expression of Tumor-Infiltrating Lymphocytes and Better Survival

The aim of this study was to investigate the clinical, histopathologic, and immunologic differences of oral squamous cell carcinoma of never-smokers/never drinkers and smokers/drinkers. Immunohistochemical staining for CD4, CD8, FoxP3, CD1a, and p16 was performed in 131 oral squamous cell carcinomas from smokers/drinkers and never-smokers/never-drinkers. Associations of smoking/drinking status with clinicopathologic data, immunohistochemical antibody expression, and survival were examined. Oral squamous cell carcinoma in never-smokers/never-drinkers was associated with the female gender (p < 0.001). Never-smokers/never-drinkers were older at diagnosis than smokers/drinkers (p < 0.001). Never-smokers/never-drinkers had more tumors in the maxilla, mandible, and tongue (p < 0.001). Pre-existing oral potentially malignant disorders appeared to be more common in never-smokers/never-drinkers (p < 0.001). Perineural invasion was more common in smokers/drinkers (p = 0.039). Never-smoking/never-drinking was associated with better overall survival (p = 0.004) and disease-specific survival (p = 0.029). High CD4+ T cell infiltration was associated with never-smoking/never-drinking (p = 0.008). Never-smokers/never-drinkers also showed increased CD8+ T cell infiltration (p = 0.001) and increased FoxP3+ Treg infiltration (p = 0.023). Furthermore, the total group of tumor-infiltrating lymphocytes was associated with never smoking/never drinking (p = 0.005). To conclude oral squamous cell carcinoma of the never-smokers/never-drinkers appears to be a distinct type of tumor, as it appears to have unique clinical and pathologic features and a more immunogenic microenvironment

Turbulent and Laminar Drag of Superfluid Helium on an Oscillating Microsphere

A magnetic sphere (radius 100 μm), levitating inside a superconducting niobium capacitor, is immersed into superfluid helium. Vertical oscillations of the sphere can be excited and detected. At resonance we measure the velocity amplitude as a function of the driving force between 0.35 and 2.2 K. In the linear regime (laminar flow) the drag is given by Stokes' solution above 1.1 K and by ballistic roton and phonon drag below 0.7 K. At larger velocities we find a sharp transition to turbulent drag which varies with the square of the velocity above a temperature independent threshold velocity

Translational oscillations of a microsphere in superfluid helium

The translational motion of a microsphere (radius 100 μm) in liquid helium is investigated. The sphere is levitating inside a superconducting capacitor and oscillates about its equilibrium position. The velocity amplitude and the resonance frequency are measured as a function of driving force and temperature (0.35 K up to 2.2 K). By increasing the driving force we first find a linear regime (laminar flow) which changes abruptly into a nonlinear one (turbulent flow). For temperatures below 0.7 K the linear drag is given by ballistic roton and phonon scattering whereas for temperatures above 1.1 K the hydrodynamic force on the sphere is described by Stoke's solution. In the turbulent regime, above a temperature independent threshold velocity, we find the drag force to be given by turbulence in the superfluid component plus an essentially laminar drag by the normal component

Pulsed radio-frequency electromagnetic fields: dose-dependent effects on sleep, the sleep EEG and cognitive performance

To establish a dose-response relationship between the strength of electromagnetic fields (EMF) and previously reported effects on the brain, we investigated the influence of EMF exposure by varying the signal intensity in three experimental sessions. The head of 15 healthy male subjects was unilaterally exposed for 30 min prior to sleep to a pulse-modulated EMF (GSM handset like signal) with a 10 g-averaged peak spatial specific absorption rate of (1) 0.2 W kg(-1), (2) 5 W kg(-1), or (3) sham exposed in a double-blind, crossover design. During exposure, subjects performed two series of three computerized cognitive tasks, each presented in a fixed order [simple reaction time task, two-choice reaction time task (CRT), 1-, 2-, 3-back task]. Immediately after exposure, night-time sleep was polysomnographically recorded for 8 h. Sleep architecture was not affected by EMF exposure. Analysis of the sleep electroencephalogram (EEG) revealed a dose-dependent increase of power in the spindle frequency range in non-REM sleep. Reaction speed decelerated with increasing field intensity in the 1-back task, while accuracy in the CRT and N-back task were not affected in a dose-dependent manner. In summary, this study reveals first indications of a dose-response relationship between EMF field intensity and its effects on brain physiology as demonstrated by changes in the sleep EEG and in cognitive performance

Extremely low-frequency electromagnetic field (ELF-EMF) does not affect the expression of a3, a5 and a7 nicotinic receptor subunit genes in SH-SY5Y neuroblastoma cell line

Neuronal nicotinic acetylcholine receptors (nAChRs) are involved in a no. of functional processes, including cognition, learning and memory, and alterations in their expression and/or activity have been implicated in various neurol. disorders such as Alzheimer's disease (AD), Parkinson's disease and schizophrenia. Epidemiol. studies have shown that exposure to electromagnetic fields (EMF) may contribute to the pathogenesis of neurodegenerative diseases such as Alzheimer's disease. Given the role of nAChRs in physiol. and pathol. conditions, we wondered whether an extremely low-frequency electromagnetic field (ELF-EMF) may affect the expression of the mols. involved in neurodegenerative processes. In order to investigate this possibility, we studied the expression of a3, a5 and a7 nicotinic subunits upon exposure of the SH-SY5Y human neuroblastoma cell line to a 50 Hz power-line magnetic field in a \"blind trial\" system; various magnetic flux densities and exposure times were applied. Our studies show that the expression of some relevant components of the cholinergic nicotinic system, which is one of the most affected neurotransmission systems in AD, did not undergo any change at mol. level by environmental exposure to ELF-EMF

Pulsed radio frequency radiation affects cognitive performance and the waking electroencephalogram

We investigated the effects of radio frequency electromagnetic fields on brain physiology. Twenty-four healthy young men were exposed for 30 min to pulse-modulated or continuous-wave radio frequency electromagnetic fields (900 MHz; peak specific absorption rate 1 W/kg), or sham exposed. During exposure, participants performed cognitive tasks. Waking electroencephalogram was recorded during baseline, immediately after, and 30 and 60 min after exposure. Pulse-modulated radio frequency electromagnetic field exposure reduced reaction speed and increased accuracy in a working-memory task. It also increased spectral power in the waking electroencephalogram in the 10.5-11 Hz range 30 min after exposure. No effects were observed for continuous-wave radio frequency electromagnetic fields. These findings provide further evidence for a nonthermal biological effect of pulsed radio frequency electromagnetic fields