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Biomedical subjects

M Schwibbe

Publications and source records attributed to M Schwibbe.

7 recordsLinked to original sources
PubMed2002

[Primates as experimental animals].

The term "primates" comprises a varied group of animals, consisting of more than 250 different species. The close evolutionary relationship to man resulted in the use of nonhuman primates as subjects of study for scientists from different research fields. In biomedical research the use of primates is restricted to questions which cannot be answered by animals with less developed physiological senses. Primates play an important role in infectious disease research, as many pathogens relevant to humans can be transferred to selected primate species. In the last few decades this applied especially for HIV-infections of man, viral hepatitides, herpesvirus infections and for quite a long time for agents of transmissible spongiform encephalopathies, too. In neurobiology, primates play an outstanding role due to the morphological-structural and functional resemblance of their CNS to that of man. Due to new developments in biomedicine, in particular in the field of gene therapeutics, it has to be expected that primates will have to be used also in future as animal models for the welfare of human health.

Animals↗
PubMed1982

Changes in physiological, EEG and psychological parameters in women during the spontaneous menstrual cycle and following oral contraceptives.

In a controlled cross-over design study performed with 14 female subjects, serum hormone levels, the EEG and a number of performance tests were recorded during spontaneous and oral contraceptive-controlled menstrual cycles. The mean alpha-frequency showed cyclic changes, i.e. slower alpha-waves during the follicular phase and faster alpha-waves during the luteal phase. Smaller cycle stage-dependent differences in the power of the theta- and beta-bands also were noted. An increase in several performance task scores was noted during the periovulatory period, whereas lowest performance scores were recorded during the late luteal and early menstrual phases. No such effects were observed in the same subjects while they were taking oral contraceptives. These results demonstrate that the gross electrical activity of the brain changes in a parallel with changed hormone levels. The changes in performance tests coincide with increasing or decreasing alpha activities in the EEG. The common underlying mechanism may be an activation of central nervous system monoaminergic pathways which are known to be involved in steroid feedback.

Adolescent↗
PubMedDate not supplied

Electrophysiological and psychological changes induced by steroid hormones in men and women.

The effects of hormonal changes during the menstrual cycle and of oral contraceptives on the EEG, heart-rate and a number of performance tasks were investigated in 16 female subjects (Ss). Powerspectral analysis in the EEG revealed significantly increased alpha-frequencies and heart-rates during the luteal phase of the menstrual cycle whereas the mean theta-frequency and power decreased. A number of psychological test variables, such as reaction time to a tone, to a flickering light and to a colour-tone sequence and the time to solve simple arithmetic problems was shorter at the periovulatory time. Another minimum was reached during the perimenstrual phase. The flicker-fusion-frequency was higher during these two periods. No such effects could be observed when the same Ss were treated with oral contraceptives. It is concluded that the phenomena observed during the luteal phase of the cycle may be the expression of a slight general arousal effect, possibly medicated by progesterone via the noradrenergic system. In a subsequent double blind study 30 male Ss were treated with an gestagenic compound (D-Norgestrel, 2.5 mg/die), an estrogenic compound (estradiolvalerate, 5 mg/die), an androgenic substance (Mesterolone, 100 mg/die) or with placebo. Only treatment with the progestational compound revealed significant changes in the EEG and the performance tests. These changes were qualitatively similar to those observed during the luteal phase of the female Ss. Under both conditions, i.e. the luteal phase and D-Norgestrel treatment, the body-temperature was significantly increased. Hence, the question whether gestagens exert their effects directly on CNS structures which modulate EEG appearance and behavior or indirectly via increased body-temperature cannot be answered convincingly.

Adolescent↗