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Safe introduction of in-hospital wireless LAN.

Insufficient research on electromagnetic interference (EMI) with medical electronic equipment by the signals of wireless LAN has been done. Therefore, electromagnetic compatibility between medical electronic equipment and wireless LAN data communications was done (IEEE802.11a, b, and g). First, to determine if medical electronic equipment is affected by EMI caused by radio waves, we irradiated radio waves to ten types of medical electronic equipment in an electromagnetic anechoic chamber. EMI were observed on three pieces of equipment. Next, to determine if the electromagnetic field emitted by the medical devices might interfere with wireless LAN communication, we measured the electric field intensity. Data analysis showed that the electromagnetic wave emitted by microwave ovens was at almost the same center frequency of the communication channel specified by the IEEE802.11b for wireless LAN. Although the number of medical electronic equipment investigated in this study was small, hospital administrators should consider electromagnetic wave testing of all medical electronic equipment to be used in areas of common wireless LAN use when planning the installation of wireless LAN.

Electromagnetic Fields↗

Mobile phone use and exposures in children.

The main difference concerning the use of mobile phones (MPs) between today's children and adults is the longer lifetime exposure of children when they grow older, due to starting to use MPs at an early age. Additionally, recent trends lead to a higher frequency of use among children, including higher popularity of MPs and features specifically designed to attract children. The prevalence of MP users is already very high and reaches >90% among adolescents in some countries. In a German study, 6% of 9-10 years old children used a MP for making calls daily; 35% owned their own MP. For children, MPs are dominant sources of radio wave exposures and relevant sources of extremely low frequency magnetic fields. For very young children, however, environmental exposure to radio waves may be of concern. In conclusion, children will have a much higher cumulative exposure to radio waves than today's adults when they are at the same age. Radio wave exposure of children may be estimated more easily, because the variety of exposure sources is smaller than for adults. As long as adverse health effects cannot be ruled out with some degree of certainty, it appears to be appropriate to instruct children and their parents about a prudent use of MPs.

Cell Phone↗

Effect of short-wave (6-22 MHz) magnetic fields on sleep quality and melatonin cycle in humans: the Schwarzenburg shut-down study.

This paper describes the results of a unique "natural experiment" of the operation and cessation of a broadcast transmitter with its short-wave electromagnetic fields (6-22 MHz) on sleep quality and melatonin cycle in a general human population sample. In 1998, 54 volunteers (21 men, 33 women) were followed for 1 week each before and after shut-down of the short-wave radio transmitter at Schwarzenburg (Switzerland). Salivary melatonin was sampled five times a day and total daily excretion and acrophase were estimated using complex cosinor analysis. Sleep quality was recorded daily using a visual analogue scale. Before shut down, self-rated sleep quality was reduced by 3.9 units (95% CI: 1.7-6.0) per mA/m increase in magnetic field exposure. The corresponding decrease in melatonin excretion was 10% (95% CI: -32 to 20%). After shutdown, sleep quality improved by 1.7 units (95% CI: 0.1-3.4) per mA/m decrease in magnetic field exposure. Melatonin excretion increased by 15% (95% CI: -3 to 36%) compared to baseline values suggesting a rebound effect. Stratified analyses showed an exposure effect on melatonin excretion in poor sleepers (26% increase; 95% CI: 8-47%) but not in good sleepers. Change in sleep quality and melatonin excretion was related to the extent of magnetic field reduction after the transmitter's shut down in poor but not good sleepers. However, blinding of exposure was not possible in this observational study and this may have affected the outcome measurements in a direct or indirect (psychological) way.

Circadian Rhythm↗

Negligible electromagnetic interaction between medical electronic equipment and 2.4 GHz band wireless LAN.

Wireless LANs using radio waves have recently gained popularity for installation in hospitals. Because electromagnetic waves transmitted from mobile telephones have been shown to cause interference with medical electronic equipment, prudence would seem necessary when introducing radio wave communication devices into hospitals. Therefore, we tested the effect of wireless LAN communication on medical electronic equipment and the effect of electronic equipment on wireless LAN communication. We observed nine pieces of electronic equipment in the operating mode while transmitting radio waves from a wireless LAN. Even when the access point was put very close to the medical electronic equipment surface and data was transmitted, no malfunction of the equipment was observed. The medical electronic equipment caused little change in the effectiveness of the communication device, although radio waves emitted from electric knives and a remote patient monitor reduced the reception rate to about 60%. The communication speed of the wireless LAN was temporarily reduced only when a microwave oven was located close to and facing the access point. Because output in Japan is limited to a maximum of 10 mW wireless LAN following the IEEE802.11b standard should be able to be installed safely in Japanese hospitals. However, wireless LAN access points should not be installed near microwave ovens.

Electromagnetic Fields↗

Magnetic resonance imaging (MRI) and diseases of the liver and biliary tract. Part 1. Basic principles, MRI in the assessment of diffuse and focal hepatic disease.

Magnetic resonance imaging (MRI) relies on the physical properties of unpaired protons in tissues to generate images. Unpaired protons behave like tiny bar magnets and will align themselves in a magnetic field. Radiofrequency pulses will excite these aligned protons to higher energy states. As they return to their original state, they will release this energy as radio waves. The frequency of the radio waves depends on the local magnetic field and by varying this over a subject, it is possible to build the images we are familiar with. In general, MRI has not been sufficiently sensitive or specific in the assessment of diffuse liver disease for clinical use. However, because of the specific characteristics of fat and iron, it may be useful in the assessment of hepatic steatosis and iron overload. Magnetic resonance imaging is useful in the assessment of focal liver disease, particularly in conjunction with contrast agents. Haemangiomas have a characteristic bright appearance on T2 weighted images because of the slow flowing blood in dilated sinusoids. Focal nodular hyperplasia (FNH) has a homogenous appearance, and enhances early in the arterial phase after gadolinium injection, while the central scar typically enhances late. Hepatic adenomas have a more heterogenous appearance and also enhance in the arterial phase, but less briskly than FNH. Hepatocellular carcinoma is similar to an adenoma, but typically occurs in a cirrhotic liver and has earlier washout of contrast. The appearance of metastases depends on the underlying primary malignancy. Overall, MRI appears more sensitive and specific than computed tomography with contrast for the detection and evaluation of malignant lesions.

Biliary Tract Diseases↗

The Nobel Prize in Physiology or Medicine in 2003 to Paul C. Lauterbur, Peter Mansfield for magnetic resonance imaging.

Imaging of human internal organs by exact and non-invasive methods is very important for medical diagnosis, treatment and follow-up. 2003 Nobel Laureates in Physiology or Medicine have made original discoveries in the use of magnetic resonance to visualize different structures. Their discoveries have led to the development of modern magnetic resonance imaging, MRI, which represents a breakthrough in medical diagnostics and research. Atomic nuclei within a strong magnetic field rotate with a frequency depending on the strength of the magnetic field. Their energy can increase if they absorb radio waves with the same frequency (resonance). When atomic nuclei return to their previous energy status, radio waves are emitted. These discoveries were awarded the Nobel Prize in Physics in 1952. During the following decades, magnetic resonance was used mainly for studies of the chemical structure of substances. In the beginning of the 1970s, 2003 Nobel Laureates made pioneering contributions, which later led to the applications of magnetic resonance in medical imaging. Paul Lauterbur (born 1929), Urbana, Illinois, USA, discovered the possibility to create a two-dimensional picture by introducing gradients to a magnetic field. Analysing the characteristics of the emitted radio waves he could determine their origin. This fact made it possible to build up a two-dimensional picture of structures that could not be visualized by other methods. Peter Mansfield (born 1933), Nottingham, England, further developed the utilization of gradients in the magnetic field. He showed, that the signals could be mathematically analysed, which made it possible to develop a useful imaging technique. Mansfield also showed how extremely fast imaging could be. It became technically possible within a decade. Magnetic resonance imaging, MRI, is now a routine method in medical diagnostics. Worldwide, more than 60 million investigations are performed each year, and the method is still rapidly evolving. MRI is often superior to other imaging techniques and significantly improves diagnostics in many diseases. MRI has replaced several invasive methods of examination and in this way has reduced the risk and discomfort of many patients. (Fig. 3, Ref. 3.).

England↗

A practical procedure to prevent electromagnetic interference with electronic medical equipment.

Problems involving electromagnetic interference (EMI) with electronic medical equipment are well-documented. However, no systematic investigation of EMI has been done. We have systematically investigated the causes of EMI. The factors involved in EMI were determined as follows: 1) Electric-field intensity induced by invasive radio waves from outside a hospital. 2) Residual magnetic-flux density at welding points in a building. 3) Electric-field intensity induced by conveyance systems with a linear motor. 4) The shielding capacity of hospital walls. 5) The shielding capacity of commercial shields against a wide range frequency radio waves. 6) The immunity of electronic medical equipment. 7) EMI by cellular telephone and personal handy-phone system handsets. From the results of our investigation, we developed a following practical procedure to prevent EMI. 1) Measurement of electric-field intensity induced by invasive radio waves from outside the hospital and industrial systems in the hospital. 2) Measurement of residual magnetic-flux density at electric welding points of hospital buildings with steel frame structures. 3) Control of the electromagnetic environment by utilizing the shielding capacity of walls. 4) Measurement of the immunity of electronic medical equipment. And 5) Installation of electronic gate equipment at the building entrance to screen for handsets.

Electric Power Supplies↗

[Modification of lethal radiation injury in mice by postradiation exposure to low-intensity centimeter-band radio frequency waves].

A clearly pronounced modification of acute radiation injury of mice has been obtained by prolonged action (for up to 23 hours) of low-intensity (5 +/- 1.5 mu Wt/cm2) radiofrequency radiation in the ranges of 2-8, 8-18 and 19-27 GHz with a swing frequency of 12-14 Hz, applied immediately after exposure to lethal dose of gamma-radiation. Survival of mice and average life duration of killed mice were increased.

Animals↗

[Effect of radio wave-induced hyperthermia on microflora of the prostate in the treatment of prostatitis associated with infertility].

The influence of hyperthermia induced by radiowaves on the microflora of the prostate in cases of male sterility was studied. The use of hyperthermia was shown to produce a stable decrease in bacteriospermia and the persistence potential of bacteria isolated from sperm. Hyperthermia produced a bactericidal effect not only on microorganisms contained in sperm but also on the microflora of prostatic tissues 1 cm deep. The study gave grounds for treating male sterility with the use of hyperthermia induced by radiowaves and a subsequent course of antibiotics to achieve the stable decrease of bacteriospermia and the restoration of the reproductive function.

Adult↗

Multimedia reviews: multimedia overload produces "symplexity".

We humans "know" from information mediated through our "natural senses." All outside signals come to us through some medium-sound waves, pressure and touch, light waves, radio and television waves, and so forth. McLuhan's famous mantra "The medium is the message" paradoxically highlighted the critical transformation of meaning when each type of medium-radio, television, drums, hand signals-by its very nature modifies the message it is transmitting. In this month's column Dr. Zingrone brings challenging new ideas to the field of human communication and vividly describes the communication distortions that occur when the overload of increasingly complex modern media results in a paradoxical diminution of meaning itself. He has coined a term for this unintended consequence and given it to his exciting new book, The Media Symplex: At the Edge of Meaning in the Age of Chaos (1). Many of us may recognize the effect created by this accelerating phenomenon-our stupefaction as we experience the onslaught of sound and visual signals produced by a television news screen, where an avalanche of rapidly changing, overlapping, and distorted visual images flash at our eyes while screeching, undulating synthetic "music" crashes about our ears. And in that chaos we struggle to find meaning,Dr. Zingrone, who worked with McLuhan and who has written extensively about his work (2,3), has succeeded in his new book to move the pioneering work of human communication scientists forward and thereby help us all to understand the developing paradox and danger of more communication yet less meaning.

Communications Media↗

[Health disorders caused by radiation].

The rapid development and distribution of radiation sources has given rise to an "Energy Pollution" paralleling the chemical contamination of the environment. It has become necessary to establish limits for the "non-ionizing radiation" as well as for the ionizing radiation to which attention has been given for a long time. The non-ionizing radiation now includes the non-ionizing electromagnetic waves - radio frequency, micro waves, optical radiation - and ultrasound. Specific effects of these different radiation qualities caused by variation in biochemical and biophysical characteristics of tissues as well as the related biological changes and the mechanism of radiation effects are discussed shortly. Some commonly occurring radiation sources are quoted.

Age Factors↗

[Possible consequences of urban pollution caused by radio frequency].

The AA. report the results of an inquest on the health effects of radio wave pollution in an area of Trieste, where television transmitters and broadcasting are installed. The following results were obtained: the measure of electromagnetic fields showed in the mentioned area a power density 10-100 times higher than that + in other zones of Trieste. According to present knowledge, the observed values of EM fields may have some psychological, behavioural and neurovegetative effects on exposed subjects. Clinical examination, integrated by the analysis of some seventy biochemical and functional parameters, showed nothing but minor changes of hypophyseal-suprarenal hormones and a relevant incidence of neurovegetative troubles. Some difficulties were found in the interpretation of psychological troubles, which may be reactive to broadcasting installation or secondary to radio wave exposure.

Adrenal Cortex Hormones↗

Factors affecting sperm motility. III. Influence of visible light and other electromagnetic radiations on human sperm velocity and survival.

Specimens of semen from fertile and infertile patients were exposed to different electromagnetic radiations, including visible light, ultraviolet (UV) light, x-rays, and high-frequency radio waves. Sperm motility was analyzed before, during, and after irradiation by the multiple exposure photography (MEP) method. No significant difference was found between controls and specimens exposed to various doses of visible and UV light and x-rays either immediately or several hours after exposure. In contrast to spermatozoa of other species that were reported to be adversely affected by visible and UV light and x-rays, human spermatozoa seem to be highly resistant to similar doses of these radiations. A deleterious influence was observed when high-frequency radio waves were applied to human spermatozoa. This may be attributed to an intracellular diathermic effect. The informative value of this study in relation to routine semen analyses and experimental studies in the physiology and comparative anatomy of spermatozoa is discussed.

Cell Survival↗

Hydration status measurement by radio frequency absorptiometry in young athletes--a new method and preliminary results.

A new method for non-invasive measurement of the human state of hydration is presented. This method is based on frequency-dependent absorptiometry of radio-waves passing through tissues. A device utilizing this method was constructed and applied to 12 young (24 +/- 1) male volunteers, who were dehydrated for 1-2.5% of their weight by performance of a physical effort (two 30 min bouts of treadmill walking/running at 2, 3, 4, 5, 6 and 7 mph, 5 min at each speed, separated by 10 min rest), under moderate heat stress (40 degrees C, 40% RH). Hypohydration level was determined by body weight measurements taken before each session, after 30 min and at the end of each session. Concomitantly, measurements of radio frequency (RF) absorption were taken. Each volunteer underwent the heat stress exercise twice: one in which no drinking was permitted, and another with free drinking. A correlation (R2 = 0.734) between weight loss and a change in the radio-waves absorption pattern was observed in most of the volunteers, in both hypo and euhydration sessions. Further work to establish the reproducibility and validity of the RF methodology in larger and different populations, i.e., females, other age groups and different health conditions, is already being researched.

Adult↗