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Biomedical subjects

M Koller

Publications and source records attributed to M Koller.

At least 181 records · Page 10Linked to original sources

[Blood lipid and blood glucose changes during single, multiple and repeated stress].

As soon as various stressors exceed specific thresholds they induce marked metabolic changes in the organism. In a number of studies these facts have been verified experimentally. In our investigations we were able to demonstrate that the pattern of stress-induced changes differs after single and multiple stress exposures and that metoblic alterations in repeated stress situations are modified by habituative and adaptative processes respectively. Stress-induced metabolic mechanisms differently develop for blood lipid fractions and blood glucose. The described mechanisms are explained according to the functions of these blood parameters during stress exposures. The differential analysis of these alterations may be important for the prevention of stress-induced metabolic disorders.

Adult↗

[Annoyance and loudness measurements in auditory fatigue and recovery under different sound exposures].

In the course of two experimental studies the individual evaluations of noise annoyance during sound exposure were compared with the experimental auditory fatigue (TTS) and the recovery functions. In both studies, in fourteen young men with normal hearing capacity, a temporary threshold shift was built up and then the subjects were submitted during the recovery period to different second-noise levels (narrow band noise and white noise). The loudness estimations and the evaluations of noise annoyance were scaled at the same points as TTS was measured. The poststimulatory recovery of hearing was significantly delayed, even at noise levels of 65 and 75 db. The evaluations of loudness and noise annoyance corresponded well with the recovery of hearing. In the first experiment, the mean values of noise annoyance ratings increased after 16 min of the second noise exposure, in spite of a further decrement of auditory fatigue. In the second experiment, the mean values of noise annoyance ratings remained almost unchanged during the secondary noise exposure. Regarding individual evaluations, however, the noise annoyance ratings of half of the subjects increased whereas the other half decreased. These results are interpreted as a habituation respectively a sensitization process.

Acoustic Stimulation↗

[Not Available].

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Dentistry↗

[Stress-induced blood protein and blood lipid changes and their dependence on learning and conditioning].

Rats were subjected to two kinds of stress and consequent changes in blood protein and lipids were investigated. Furthermore, an attempt was made to ascertain whether or not increases or decreases in these blood parameters were reproducible by conditioning. In the first experiment animals were subjected to stress in a modified running wheel (Noble Collip drum). A series of 10 conditional stimuli (light-sound combined) was delivered together with the stress-producing stimulus. After the first exposure to stress a relative alpha1-globulin increase was observed. After 10 stress exposures the hitherto neutral stimulus alone produced a conditioned increase in the alpha1-globulin fraction. The gamma-globulin values were decreased after the first exposure to stress, but increased after 10 stress exposures. This increase could also be conditioned. In the second experiment "white noise" stress was used (110 dB). The conditional stimulus was light. After short exposure to the stress-inducing stimulus, the gamma-globulins showed a slight drop and remained thus during the whole experiment. The analysis of blood lipids showed increased stress values for alpha-lipoprotiens and reduced values for beta-fractions. Cholesterol and triglycerides reacted like the beta-lipoproteins. The total blood lipid content was, however, increased. The conditioned increase in alpha-lipoproteins and total lipids was statisticallysignigicant. It is noteworthy that the conditioned alpha-lipoprotein levels shoeed significant differences between experimental and control groups. The conditioned stress increased the levels of cholesterol and triglycerides, whereas under real stress conditions decreases were found. Research on "conditioned stress" could beof improtance in regard to clinical aspects of coronary heart disease.

Animals↗