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Biomedical subjects

J H Bernhardt

Publications and source records attributed to J H Bernhardt.

At least 19 recordsLinked to original sources
PubMed2005

[Electrosmog, cellular phones, sunbeds etc. -- adverse health effects from radiation? Health aspects of non-ionizing radiation].

This review supplies a survey of the three physical influences, i. e. UV radiation, high-frequency electromagnetic fields of radio telephone systems and other wireless radio applications as well as low-frequency fields of electric power supply. The exposure to UV radiation must be considered to be by far the highest health risk. The annual rate of about 2000 deaths from skin cancer in Germany, mainly caused by extensive exposure to solar UV radiation, demands protective measures. Teaching reasonable behaviour is the supreme issue. Recommended protective measures in the order of their effectiveness are protection by adaptation of behaviour, by clothes, sun hats and sunglasses as well as by sun creams. Children are the most important target group. With regard to UV tanning appliances it is recommended not to use artificial UV radiation for cosmetic purposes because of the related health risks. For the assessment of health impairments caused by exposure to electromagnetic fields, direct field reactions due to induced electric body currents, reactions on the surface of the body or heating effects should be separated from indirect field reactions (e. g. electric shocks and burns) due to contact currents or interference with electronic body aids and implants. Risk assessment has led to recommendations of threshold values which-in agreement with international research results-exclude all impairments of health caused by direct field reactions scientifically proven to date. Contrary to public concerns, which are mostly related to base transmitters of radio telephone systems, exposure due to handheld radio telephones (cellular phones) should rather be considered from the viewpoint of precautionary health protection, since it is more likely that their use can lead to high exposure of the user. Due to the protective measures provided so far and observance of the threshold values based on scientific results, exposures do not lead to health impairments-not even in children. Because of the introduction of new technologies more portable devices are to be expected that may be operated near the body. This will further increase the exposure of people to high-frequency electromagnetic fields.

Cell Phone↗
PubMed1999

Analysis of tractor-related deaths in North Carolina from 1979 to 1988.

This descriptive study examined 342 fatalities involving tractors and attachments that occurred during a 10-year period in North Carolina from 1979 to 1988. Reports of the North Carolina Office of the Chief Medical Examiner and medical examiner's certificates of death were reviewed using the public health model of causation. Data were collected on characteristics of thefatally injured (host), including age, occupation, blood alcohol concentration and length of survival; characteristics of the injury event (environment), including type of accident, weather conditions and terrain; and characteristics of the agent, including both the tractor and attachments, if any, in place at the time of injury. Ninety-eight percent of the victims were male. Victims ages 65 and older accounted for 38 percent of fatal injuries, and 11 percent were 18 years of age or younger. Only slightly more than one-half of the victims (54 percent) were full- or part-time farmers. Forty-four percent of the deaths were to nonfarmers who were not in the act of farming. Nineteen percent of tested victims had a detectable blood alcohol level. Almost three-fourths of the victims died in the first hour after injury and 87 percent within the first 24 hours. In the majority of accidents, the tractor operator was a victim of a rollover or runover. This study provided detailed characterization of the fatally injured and, to the extent possible, the tractor involved and the injury event itself. However, additional methods of data collection are needed to provide further characterization of the injury event and the injury agent to design and support prevention programs for tractor users.

Accidents, Occupational↗
PubMed1998

[Prevention of health risks in the use of MRI procedures. Recommendations of the Radiation Protection Commission].

Magnetic resonance imaging is used routinely with much success for various problems in different medical disciplines. However, the patient is exposed to static as well as to time-dependent magnetic fields and radiofrequency electromagnetic fields. In 1997 the Strahlenschutzkommission, the German Radiological Protection Commission, passed a recommendation on the use of magnetic resonance in medical diagnostics. In this recommendation basic values related to thresholds for physiological effects and limits for restricted and unrestricted use are given. In the following the aim and applicability of this recommendation are discussed, as well as the thresholds and different limits for the static magnetic fields, the gradient fields and the radio-frequency fields. Additionally, advice is given for the protection of high-risk patients, personnel, and the general public, together with further safety advice as well as recommendations for users and manufacturers.

Dose-Response Relationship, Radiation↗
PubMed1988

The establishment of frequency dependent limits for electric and magnetic fields and evaluation of indirect effects.

The biophysical model described in this paper has been used as basis for the preparation of the German standards which determine and define limits of exposure to electric or magnetic fields below several MHz, including 50/60 Hz. The electric field strength within the tissue is considered decisive for the biological effect in the low frequency range. Threshold values of field strengths and current densities including biological effects are compared. It is possible to establish "safe", "dangerous" and "hazardous" current density curves as a function of frequency. To define exposure limits, the field strength or current density causing injury should be reduced by a factor exceeding 100 in order to avoid well established biological effects. The electric and magnetic field strengths in the human environment are correlated with the corresponding electric current density induced in the human body. This enables "safe", "dangerous" and "hazardous" levels of current density in the human body to be correlated with the external electric or magnetic field strength. Additionally to the direct field effects indirect effects must be considered. In the second part of this paper data on touch voltages and currents are summarized and evaluated with regard to their health risk. Furthermore, as an example for indirect effects the interference of electric and magnetic fields with pacemakers is considered.

Animals↗
PubMed1984

[Health risks from the use of NMR tomography and in vivo NMR spectroscopy].

As a result of consultations with the Commission "Non ionizing Radiation" together with additionally appointed experts, the Federal Health Office has published "Recommendations on health risks caused by magnetic and high frequency electromagnetic fields in NMR-tomography and in-vivo-NMR-spectroscopy". The basis of these consultations was a list compiled by the authors on the effects from fields present during NMR application. This compilation contains some rough estimates. This publication is intended to document the compilation as a basis for recommendations published by the federal health office. Since such estimates need to be supplemented it is planned to review this compilation from time to time when new results are available.

Electromagnetic Fields↗