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Biomedical subjects

E Hartmann

Publications and source records attributed to E Hartmann.

At least 181 records · Page 10Linked to original sources
PubMed1978

Daytime state and night-time sleep; a sleep study after a marathon group experience.

The nocturnal sleep of 9 subjects was recorded under two conditions following a "normal" weekend and following a weekend in which the subjects participated in a psychodynamic marathon group activity. Differences between the two experimental conditions were found for sleep latency and on one measurement of D-latency. Both latencies were reduced after the marathon group. No differences were found on the remaining 12 measurements. These findings tend to reaffirm the stability of sleep patterns under various pre-sleep conditions.

Adult↗
PubMed1978

[Studies of drugs without randomization (author's transl)].

Post marketing studies of drugs are frequently performed without randomization. In this paper the most important differences between controlled clinical trials and epidemiologic studies are discussed from a cognitive theoretical point of view. It is shown that on the transition of informations from the basic population to the document many biases may arise so that the feasibility of interpreting epidemiologic studies is doubtful. Hence, epidemiologic studies only allow us to make statements on differences between populations but not on the reasons causing them; they merely contribute to the generation of certain hypothesis on the action of drugs. These hypothesis can only be tested in experiments.

Drug Evaluation↗
PubMed1977

The insomnia of 'sleeping in a strange place': effects of l-tryptophane.

Forty-two normal human subjects were studied in the sleep laboratory for one night each. Fourteen were given placebo at bedtime, 14 took l-tryptophane 1 g, and 14 took l-tryptophane 3 g. Both tryptophane groups had significantly lower sleep latency than the placebo group. The usually discarded 'first laboratory night' produces a mild situational insomnia in normal persons and thus can be useful in certain sleep studies.

Adaptation, Psychological↗
PubMed1977

Sleep deprivation deficits and their reversal by d- and l-amphetamine.

Vigilance performance, waking EEG patterns and mood were studied before and after one night of sleep deprivation in normal males. The effects of d-amphetamine 10 mg, l-amphetamine 10 mg and placebo on these measures were compared. Changes were found in all three measures after one night of sleep-deprivation. d-Amphetamine was more powerful than l-amphetamine in reversing sleep deprivation effects on vigilance and on waking EEG.

Adult↗
PubMed1977

L-tryptophan: a rational hypnotic with clinical potential.

The author states that the use of the amino acid L-tryptophan as a hypnotic might avoid the problems of nonspecificity in the currently used CNS depressants because L-tryptophan is chosen on the basis of the chemistry of normal sleep rather than on a purely empirical basis. He reviews nine studies from his laboratory dealing with the effects of L-tryptophan on sleep. Studies in rats, normal human subjects, and subjects with mild insomnia all demonstrate that L-tryptophan reduces sleep latency. Polygraphic studies demonstrate that L-tryptophan, unlike hypnotics, does not produce distortions of sleep physiology when first administered, on long-term administration, or after withdrawal.

Animals↗
PubMed1977

[Effect of oxytocin on regional 3H-orotic acid uptake in rat brain].

The uptake of the RNA precursor [3H] orotic acid by 18 brain regions of male rats was measured after intracarotid injection and a survival time of 15 s. Ocytocin added to the injected solutions (final concentrations: 1 to 1000 mU/ml) caused a dose-dependent enhancement of tracer uptake by 11 areas. Some of these regions (e.g. hippocampus) are thought to be involved in the behavioral effects of vasopressin and other peptide hormones (Van Wimersma Greidanus et al., 1975 a). Results of experiments in which the net uptake of tritiated water was used as a measure of relative blood flow led us to the conclusion that the blood-brain barrier permeability to [3H] orotic acid rather than the cerebral blood flow is changed by ocytocin. The present results support the assumption that the enhanced precursor supply caused by ocytocin might contribute to the influence of this peptide hormone on memory consolidation.

Animals↗
PubMed1976

Sleep: effects of d- and l-amphetamine in man and in rat.

Almost identical results are reported in man and in rat for the effects of the amphetamine isomers on polygraphically recorded sleep. In both species, dextro-amphetamine produces a significantly greater increase in waking time. In both species, the two isomers have equal effects in reducing desynchronized sleep time. These findings combined with other recent data suggest that dopamine plays a direct rolw in wakefulness while norepinephrine is related inversely to amolnts of desynchronized sleep.

Adult↗
PubMed1976

[Blood coagulation and fibrinolysis in women receiving estrogen, gestagen and estrogen-gestagen-contraceptives (author's transl)].

Eight femal subjects received a contraceptive with a low estrogen content (Neogynon), the estrogen component (50 mug ethinylestradiol) and consecutively the gestagen component (250 mug D-Norgestrel) of the contraceptive. Each treatment cycle was followed by a control cycle. At various times of the control and therapy cycles several coagulation and fibrinolytic parameters were investigated. Statistical analyses were performed by multivariate two-factorial analysis of variance. Plasminogen exhibities a statistically significant increase during the treatment with ethinylestradiol and the combination of this steroid with D-norgestrel. No significant changes were found for all other parameters, including partial thromboplastin time, fibriogen, factors X, IX, VIII, factor VIII-related antigen, antithrombin III and fibrin(ogen)degradation products.

Adult↗
PubMed1976

The effect of alpha and beta adrenergic receptor blockers on sleep in the rat.

We investigated the effects of the beta adrenergic blocker, propranolol, and the alpha adrenergic blocker, phenoxybenzamine, on sleep patterns in the rat by means of multiple 8-hr and 24-hr polygraphic recordings. Propranolol had no clear effect on time spent in waking, synchronized sleep or desynchronized sleep. Phenoxybenzamine at a dose of 40 mg/kg produced a significant increase in desynchronized sleep time and in the number of desynchronized sleep periods. This is consistent with the view that there may be a mechanism inhibiting the onset of desynchronized sleep periods which involves norepinephrine acting at alpha adrenergic receptors in the brain.

Animals↗
PubMed1975

Influence of pregnancy on the kinetics of insulin.

The disappearance rate of intravenously injected insulin was investigated in the serum of 30 women during the third trimester of pregnancy and 6 to 8 weeks post partum, in order to determine whether pregnancy has an influence on insulin kinetics in human subjects. Both women with unimpaired glucose tolerance and those with latent diabetes were included in this study. The disappearance rate of exogenous serum insulin in pregnancy was characterized by a two-compartment model. Multivariate analyses of variance were used to determine whether the estimated parameters of this model during pregnancy differ from those obtained after the puerperium and whether the insulin kinetics are altered when carbohydrate metabolism is disturbed. The kinetics of insulin during pregnancy did not differ from those after pregnancy. Thus, hyperinsulinemia observed in pregnancy cannot be explained by a change in the insulin kinetics. It appears improbable that the insulin-degrading enzyme activities of the placenta participate in degradation of insulin circulating in the maternal blood. A connection between the decline of glucose tolerance during pregnancy and the kinetics of exogenous insulin could not be found.

Adult↗