Biomedical subjects

Bernd Feige

Publications and source records attributed to Bernd Feige.

24 records · Page 2Linked to original sources

PubMed2002

Nocturnal cortisol and melatonin secretion in primary insomnia.

The present study investigated evening and nocturnal serum cortisol and melatonin concentrations in patients with primary insomnia to test if this clinical condition is accompanied by an increase of cortisol secretion and a simultaneous decrease of nocturnal melatonin production. Ten drug-free patients (4 males, 6 females) with primary insomnia (mean age+/-S.D.: 39.2+/-9.1 years) and 10 age- and gender-matched healthy controls participated in the study. All subjects spent three consecutive nights in the sleep laboratory with polysomnography. Measurement of cortisol and melatonin (from 19:00 h to 09:00 h) was performed prior to and during the last laboratory night. Contrary to expectation, cortisol secretion did not differ between healthy controls and insomniac patients. On the other hand, nocturnal melatonin production was significantly diminished in insomniac patients. Polysomnographically determined sleep patterns, in contrast to subjective ratings of sleep, demonstrated only minor alterations of sleep in the insomniac group. The lack of increased cortisol secretion in the patients with primary insomnia indicates that results from studies on the biological consequences of experimental sleep loss in healthy subjects cannot be applied to primary insomnia in general, especially if there are only minor objective sleep alterations. In spite of the negligible objective sleep disturbances in the present sample, nocturnal melatonin production was reduced, which tentatively suggests a role for this hormone in primary insomniacs. The pathophysiological significance of this finding is, however, still a matter of debate.

Adaptation, Physiological↗

PubMed2002

The tryptophan depletion test: impact on sleep in primary insomnia - a pilot study.

The application of the tryptophan depletion test is based on the assumption that the decrease of plasma or serum tryptophan concentration following the ingestion of a tryptophan-free amino acid drink reflects a central nervous effect on serotonin metabolism. In the present study the impact of tryptophan depletion on polysomnographically recorded sleep in patients with primary insomnia was studied. Fifteen patients with primary insomnia slept for four nights in the sleep laboratory. Prior to the fourth night the tryptophan depletion test was applied. Sleep EEG variables served as outcome parameters. Patients with primary insomnia, compared to baseline values showed a highly significant decrease of serum tryptophan concentrations after the amino acid drink. Concerning sleep parameters, stage 1 (% sleep period time=SPT) was increased, whereas stage 2 (% SPT) was decreased. Indices of phasic activity of rapid eye movement (REM) sleep (REM density) were increased after the tryptophan depletion compared to baseline. The results suggest a negative impact of tryptophan depletion on sleep continuity and a stimulating effect on phasic measures of REM sleep in patients with primary insomnia.

Adult↗

PubMed2002

Periodic limb movements during sleep in alcohol dependent patients.

Complaints of sleep disturbances are common among alcohol dependent patients during subacute abstinence. Recovered patients may show persistent sleep abnormalities for months or even years. In the present study we studied the issue whether periodic limb movements in sleep and disturbances of nocturnal respiration are more frequent in alcohol dependent patients than healthy subjects and may be of predictive value for sustained abstinence vs. relapse after withdrawal. Forty alcohol dependent patients spent three nights in the sleep laboratory at three time points: 2 to 3 weeks after withdrawal (T0) and at follow-up investigations 6 (T1) and 12 (T2) months after discharge from the hospital. Measurements of PLMS-arousal index and nocturnal respiration were performed during the first laboratory night of each measurement point. Alcohol dependent patients displayed a significantly enhanced PLMS-arousal index at T0 compared to age- and gender-matched healthy subjects, whereas no alterations of nocturnal respiration were found.The PLMS-arousal index at T0 was significantly elevated in patients who relapsed during the next 6 months compared to abstinent patients. In a discriminant function analysis the PLMS-arousal index classified 55 % of the patients correctly with respect to outcome after 6 months. It correctly predicted 80 % of abstainers and 44 % of the patients who relapsed. According to neurobiological models of the generation of PLMS and the etiopathology of alcohol dependence a genetically determined vulnerability of the dopaminergic system is discussed as a factor underlying an increased risk of relapse in a subgroup of alcohol dependent patients.

Adult↗

PubMed2002

Fluoxetine and sleep EEG: effects of a single dose, subchronic treatment, and discontinuation in healthy subjects.

The goals of the current study were to evaluate whether a single dose of fluoxetine causes qualitatively different changes in sleep architecture and NREM sleep EEG than subchronic administration in healthy subjects and to determine degree and duration of such changes after the single dose and after discontinuation from subchronic administration. Our hypothesis was that subchronic intake should cause changes qualitatively different from the single dose and that such changes could be sufficiently long-lived to suggest the possibility of a dosing in intervals of several days. Ten healthy volunteers first took one single 60-mg dose of fluoxetine and a week later started to take a 40-mg dose every morning for three weeks. Sleep laboratory nights included two nights before and four nights after the single dose and every second night for two weeks after discontinuation from subchronic administration. The single dose caused only a slight increase in drug plasma concentrations but relatively clear changes in sleep structure. After discontinuation from subchronic administration, sleep quality indices normalized quickly (within 2-4 days), whereas REM latency and spectral power effects correlated with total SSRI plasma concentration and normalized more slowly, corresponding to the drug plasma half-life of about 10 days. The REM fraction of the sleep period showed a rebound, whereas the delta sleep ratio did not correlate with drug plasma levels and yet remained increased after the medication interval. Thus, the only qualitative difference seen between acute and subchronic medication was the initial sleep disturbance. REM latency and especially the delta sleep ratio remained increased for several days after discontinuation from subchronic administration, indicating the possibility of a less-than-daily maintenance medication after an initial daily interval. Finally, the pattern of change observed for the delta sleep ratio indicates that it may be due to secondary, adaptive effects possibly linked to the antidepressant effect of fluoxetine in depressed patients.

Adult↗

PubMed2002

Effects of the neuropeptide substance P on sleep, mood, and neuroendocrine measures in healthy young men.

The neuropeptide substance P (SP) has been supposed to be involved in the etiopathology of affective disorders, mainly because of the finding of increased levels of SP in the cerebrospinal fluid of depressed patients and the preliminary evidence of antidepressant effects of SP-receptor antagonists in depressed patients. We investigated whether SP may induce changes of sleep, mood and neuroendocrine measures that are similar to those in depressed patients. In a double-blind, randomized cross-over design, 12 healthy young men were investigated in two blocks of three consecutive nights, in which SP or NaCl was intravenously infused during the third night. Polysomnographic recordings were obtained during all nights and blood samples were drawn every 30 min during the third night. Infusion of SP caused a significant worsening of the mood of the subjects, led to an increase of REM latency and time awake during the SP-infusion intervals, caused increased stage 1 sleep in the first part of the night, and led to increased cortisol and thyroid stimulating hormone levels and a trend for decreased growth hormone levels. These effects can be interpreted as evidence for a central arousing effect of SP. Further studies should focus on the effects of substance P in patients with depressive or other psychiatric disorders.

Adult↗

PubMed2002

Assessing cerebral dysfunction with probe-evoked potentials in a CNV task -- a study in alcoholics.

OBJECTIVES: Contrary to event-related potential (ERP) components N1, N2 and P3, slow ERPs have rarely been used in assessing cerebral dysfunction in mental disorders. Focussing on slow waves (SWs) and on patients with mild cerebral dysfunction, we recorded ERPs in alcoholics using a dual task design. METHODS: ERPs to auditory probes presented either 1s before the warning or 1s before the imperative stimulus of a visual contingent negative variation (CNV) paradigm were recorded from 33 scalp electrodes in 27 alcoholics following detoxification and 12 healthy controls. Independent component analysis (ICA) was used to separate potentially overlapping spatial components. RESULTS: In alcoholics compared to controls, probe ERPs showed increased N2, decreased P3 and increased negative SWs of two types appearing pre- and post-P3, respectively. Both negative SWs significantly correlated with neuropsychological indices reflecting verbal intelligence and memory functions. The increase in probe-evoked N1 and P3 potentials during CNV, putatively associated with enhanced cortical excitability, significantly correlated with clinical features of protracted alcohol withdrawal syndrome in alcoholics. CONCLUSIONS: Our experimental approach revealed two types of negative SWs which strongly correlated with neuropsychological deficits of mildly impaired patients. It is suggested that our methods might enhance diagnostic efficiency of ERPs. An electrophysiological measure of protracted alcohol withdrawal might be useful for managing central nervous system dysfunction in alcoholics.

Adult↗