Manfred Haider

Different patterns of light exposure in relation to melatonin and cortisol rhythms and sleep of night workers

Koller M, Harma M, Laitinen JT, Kundi M, Piegler B, Haider M. Different patterns of light exposure in relation to melatonin and Cortisol rhythms and sleep of night workers. J. Pineal Res. 1994: 16: 127–135.

Clastogenic effects of radiofrequency radiations on chromosomes of Tradescantia

The clastogenicity of electromagnetic fields (EMF) has so far been studied only under laboratory conditions. We used the Tradescantia-micronucleus (Trad-MCN) bioassay in an in situ experiment to find out whether short-wave electromagnetic fields used for broadcasting (10-21 MHz) may show genotoxic effects. Plant cuttings bearing young flower buds were exposed (30 h) on both sides of a slewable curtain antenna (300/500 kW, 40-170 V/m) and 15 m (90 V/m) and 30 m (70 V/m) distant from a vertical cage antenna (100 kW) as well as at the neighbors living near the broadcasting station (200 m, 1-3 V/m). The exposure at both sides of the slewable curtain antenna was performed simultaneously within cages, one of the Faraday type shielding the field and one non-shielding mesh cage. Laboratory controls were maintained for comparison. Higher MCN frequencies than in laboratory controls were found for all exposure sites in the immediate vicinity of the antennae, where the exposure standards of the electric field strength of the International Radiation Protection Association (IRPA) were exceeded. The results at all exposure sites except one were statistically significant. Since the parallel exposure in a non-shielding and a shielding cage also revealed significant differences in MCN frequencies (the latter showing no significant differences from laboratory controls), the clastogenic effects are clearly attributable to the short-wave radiation from the antennae.

Personal light dosimetry in permanent night and day workers.

Light exposure was measured in six day and six night watches (working 12-hour shifts five days in a row) during 48 h on work days and 48 h on days off using a photocell with a sensitivity corresponding to photopic vision. The photocell was mounted on a frame of spectacles, thus measuring in viewing direction. Light exposure was low both in night and day watches; however, in night watches exposures were significantly lower: On work days, night watches spent a mean of 13 min above 1,500 lx, day watches 52 min; on days off, night watches spent 3 min above 1,500 lx but day watches 89 min. Unexpectedly, night watches had no higher exposure during days off. We suspect that this is due to a light avoidance tendency in permanent night workers. High negative correlations between the acrophases of subjective state (e.g., alertness and mood) and light exposure in night watches indicate that bright light would probably increase desynchronization between subjective state, sleep, and activity.

Lead in drinking water of Vienna in comparison to other European countries and accordance with recent guidelines.

Due to the decrease of lead intake via inhalation route, the oral route, particularly from drinking water in cities with lead installations, gains relative importance. In two surveys a total of 288 objects were investigated and 1768 samples were analysed. The first series with 51 objects using a field experimental approach systematically investigated the effects of daytime, floor and flushing. Because only objects built before 1945 and suspected of lead plumbing were chosen, the first series approaches worst case conditions. The second series investigating 237 randomly chosen objects stratified according to time of consumption should allow inferences about the present situation in Viennese households. Each sampling procedure comprised one sample without flushing and three further samples with flushing of 1 l, 3 l and 10 l, respectively. Statistically significant decreases occurred between these flushing conditions. The sampling data of the upper floors showed significantly higher lead contents compared to the lower floors, which indicates that house installations are the main causes of lead contamination in Viennese drinking water. In comparison to other European countries the percentage of samples exceeding the guideline levels (50 micrograms/l as current value and 10 micrograms/l as target value) was lower.

Occurrence of infraslow potential oscillations in relation to task, ability to concentrate and intelligence

The occurrence of infraslow potential oscillations (ISPOs) of the brain was investigated during a listening and a resting condition in 44 subjects (Ss) with high (HAC) and low ability to concentrate (LAC). The occurrence of ISPOs was found in 36% of the Ss. While in the HAC group the occurrence of ISPOs did not change from listening to resting, in the LAC group Ss with ISPOs were affected by experimental conditions, showing ISPOs during the listening condition. For Ss with ISPOs only during listening a lower score was found for ability to concentrate, suggesting ISPOs as a possible underlying mechanism. For Ss with stable ISPOs a higher I.Q. was found compared to Ss without ISPOs.

Changes in discrimination learning and brain activity (ERP's) due to combined exposure to NO and CO in rats☆

Carbon monoxide (CO) and nitric oxide (NO) are air pollutants frequently appearing in combination. Information available on the mechanisms of NO intoxication suggests that in mixtures with CO additive effects should be assumed. In this study CO and NO-induced changes and their interaction were investigated at different levels of integration: carboxyhemoglobin (COHb) and methemoglobin (met-Hb) formation as well as centrally mediated effects were analyzed using evoked potential techniques and behavioral data from a complex discrimination learning experiment. Slight enhancements of COHb and met-Hb concentrations were seen for the combined CO + NO exposure conditions at low and high exposure levels when compared to isolated exposure conditions. The performance decrease was clearly higher under NO exposure than under CO exposure. Decrements were overadditive when simultaneous CO + NO exposure was used in higher concentration. Both gases affected early evoked potential components (P10, N30) in the same way: latencies were prolonged and amplitudes increased. Later potential components were differently influenced by CO and NO. Mainly the N150 amplitude was decreased in NO exposure and increased in CO conditions. N150 amplitude was also decreased after combined CO + NO exposure. At high levels this effect was overadditive indicating a dominant role of NO in the CO + NO combinations used in this experiment.

Different storage methods for biopotential skin electrodes (sintermetallic Ag/AgCl) and their influence on the bias potential

SummaryThe aim of the present study was to investigate the influence of various methods of storage on the Differences in Electrode Potential (DEP). For periods of 22 h each, 10 Ag/AgCl sintered metal biopotential skin electrodes were stored in 4 media: “dry”, in a 0.9% NaCl solution, in distilled water and in electrode jellies. When storing the electrodes in 0.9% NaCl, distilled water, and electrode jelly all the electrodes of one make were stored together in a container filled with the medium in question, with and without the application of an external short circuit. After storage the electrodes were filled with one of 3 electrode jellies (Beckman Electrode Electrolyte, Parker Spectra 360, Siemens Electrode Gel). The DEPs between each two electrodes were measured 10, 30, 60 and 120 min after filling. The results show no difference for the two makes of electrodes (Beckman and IVM), but clear differences (up to factor 50) were observed in the electrode jellies used. The method of storage has a significant influence on the DEP. Dry storage yielded the lowest values (p<0.001) for all electrodes and electrode jellies (x between 84 and 318 ΜV) and the highest stability. When stored in 0.9% NaCl, distilled water and electrode jelly, both with and without external short circuit, the electrodes showed DEPs in the mV range and drifted strongly during the period of observation, except after short-circuited storage in 0.9% NaCl, when a phase of stability is reached after 60 min.

Cortical DC-Shifts Related to Sustained Sensory Stimulation and Motor Activity

On the question of event-related slow (DC) potentials in the brain, Haider et al. (1981) published a review paper some years ago. Since that time our group has tried to deal with brain DC shift related to longer term information processing and motor activity. This is of course only possible with the use of special DC electrodes and special DC amplification systems.

Interactions between noise and air pollution

Abstract A theoretical framework for the discussion of interaction effects between noise and air pollutants (e.g., carbon monoxide, heavy metals, and organic solvents) on the auditory system as well as on extraaural systems is presented. The interactions are categorised into five groups: local interaction, independent action, dependent aftereffects, transaction, and general interaction. Information on combined effects of carbon monoxide and noise, as well as carbon monoxide and nitrogen oxide, serve as examples how the different intensities of effects, as well as the different effect levels, may be taken into account within the described theoretical framework. The problem of sensory interactions as well as combined annoyance effects are analysed with the same conceptual approach.

Combined effects of mental load and background noise on CNS activity indicated by brain DC potentials

Abstract To assess combined effects of noise and mental load on brain activity, DC potential shifts were evaluated. In a 4-way repeated analysis of variance (ANOVA) design with Type of Noise, Sound Intensity, Mental Load, DC Recording Location as factor, 2-min epochs of noise exposure were compared in 18 subjects. Significant main effects were found for Type of Noise (white noise and street noise showing greater positive shifts than music sound), Mental Load (more positive shifts for mental load vs. no mental load), and DC Recording Location. Statistically significantly higher order interaction effects were also found. Low intensity of music sound diminished the mental load CNS activity (DC shifts), interpreted as a possible compensatory effect of soft music on mental load. The effect of mental load under street noise and white noise conditions depends on the CNS activity (DC shifts) caused by these background noises alone, showing a ceiling effect. Results indicate that CNS activity (DC shifts) apparent during mental load are changed by acoustic stimulation additionally applied and that this effect is dependent on type of noise/sound and sound intensity.