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Biomedical subjects

U Hemmeter

Publications and source records attributed to U Hemmeter.

33 records · Page 2Linked to original sources
PubMed1994

Increased trimipramine plasma levels during fluvoxamine comedication.

A depressive patient, a non-responder to trimipramine (TRI), was comedicated first with citalopram (CIT) and then with fluvoxamine (FLUV). Both the TRI-CIT and TRI-FLUV combination treatments led to a worsening of the depressive state and to the appearance of panic attacks. The addition of FLUV to TRI resulted in a twofold increase of the plasma levels of TRI and to a slight increase of its N-demethylated and 2-hydroxylated metabolites. These results suggest that the interaction between FLUV and TRI occurred at the level of cytochrome P-450IID6 and cytochrome P-450meph in this patient, phenotyped as an extensive metabolizer of both dextromethorphan and mephenytoin. The adverse effects were possibly due to (a) a pharmacokinetic interaction between CIT and FLUV with TRI and/or (b) alterations in serotonergic and/or dopaminergic neurotransmission.

Aged↗
PubMed1994

[Cortisone-induced delusional depression in systemic lupus erythematosus].

A case of systemic lupus erythematodes (SLE) with development of a delusional depression is presented. Psychiatric symptoms in patients with SLE and in patients treated with glucocorticoids are discussed. The main psychiatric side effects of a therapy with steroids are a dose-dependent, reversible dementia like syndrome and a probably not dose-dependent provocation of psychosis. Furthermore the role of the dysregulation of the limbic-hypothalamic-pituitary-adrenocortical axis in major depression is stressed and consequences for psychopharmacological treatment are emphasized.

Adult↗
PubMed1993

Neurosteroid pregnenolone induces sleep-EEG changes in man compatible with inverse agonistic GABAA-receptor modulation.

The steroid pregnenolone (P) and its sulfate (PS) can accumulate in the central nervous system independent of peripheral sources. Pharmacologically, the sulphated form of P interacts with the GABAA receptor complex, and functional assays show that this steroid behaves as an allosteric GABAA receptor antagonist. The present study explored the effect of a single dose of P upon the sleep-EEG and concurrent secretion of growth hormone and cortisol in male volunteers. P increased the amount of time spent in slow wave sleep and depressed EEG sigma power. Sleep-associated nocturnal cortisol and growth hormone secretion remained unchanged, ruling out the possibility that P exerted its effect via altered regulation of these hormones. Furthermore, results from in vitro studies on the potency of P to activate gene transcription via corticosteroid receptors made a genomic action of P via hormone receptor-sensitive DNA sequences unlikely. We conclude that P acts in a non-genomic fashion at or in the vicinity of the benzodiazepine binding site, modulating allosterically the GABAA receptor like a partial inverse.

Adult↗
PubMed1993

Effects of the novel acetylcholinesterase inhibitor SDZ ENA 713 on sleep in man.

A novel brain-selective acetylcholinesterase inhibitor, SDZ ENA 713, is under development for the treatment of dementia of the Alzheimer type. To determine the threshold dose for central activity, single doses of the compound were administered to 20 young male volunteers in a double-blind cross-over design and the effects on the sleep electroencephalography studied. The first group of eight volunteers received in random order: placebo, 0.5 mg; and 1 mg SDZ ENA 713. The second group of 12 volunteers received: placebo, 1.3 mg; and 2 mg SDZ ENA 713. Sleep quality was not affected by the study medication, which was well tolerated by all subjects. A statistically significant increase in rapid-eye movement sleep density was observed after doses of 1 mg, 1.3 mg, and 2 mg. Rapid-eye movement latency and slow-wave sleep were not altered. The results demonstrate that SDZ ENA 713 is centrally active in man at well-tolerated doses.

Adolescent↗
PubMed1993

[EMG abnormalities in REM sleep of addicted patients].

EMG abnormalities such as short muscle twitches and marked increase of muscle tone can be identified during REM sleep. We compared the polysomnographic parameters of ten alcoholic patients who were sober and medication-free for at least four weeks, five methadone-substituted politoxicomanic patients (MSP) and ten healthy control patients. The alcoholics and the MSP showed significantly more twitches than the control patients, and the MSP had significantly more tonus increase than the alcoholics and the controlled. The polysomnographic measures differed significantly between the groups in sleep architecture. The alcoholics had significantly less slow-wave sleep (SWS) and more REM sleep, the MSP had a longer REM latency and more of stage 2. Dividing all subjects along the median of the two EMG abnormalities, the group which showed a high number of twitches had significantly less SWS with a compensatory increase of stage 2. The two EMG measures, which were scored additionally, may provide a useful additional information in the differentiation of sleep disturbances in alcoholic and methadone-substituted patients. The interaction between the occurrence of these EMG abnormalities and the other polysomnographic measures in our study needs further clarification.

Adolescent↗
PubMed1992

Effects of growth hormone-releasing hormone and somatostatin on sleep EEG and nocturnal hormone secretion in male controls.

When applied centrally to animals, growth hormone-releasing hormone (GHRH) stimulates slow-wave sleep (SWS), whereas somatostatin (SRIF) increases REM sleep. We investigated whether these peptides also affect the sleep EEG in humans when given intravenously by comparing polysomnographically the effects of four boluses of (1) placebo, (2) 50 micrograms GHRH or (3) 50 micrograms SRIF administered at 22.00, 23.00, 24.00 and 1.00 h to 7 male controls. In addition, we collected blood samples through a long catheter every 20 min from 22.00 to 7.00 h and measured plasma cortisol and growth hormone (GH) levels. In comparison with SRIF and placebo, GHRH produced a significant increase in plasma GH concentration throughout the night (mean +/- SD: 10.8 +/- 2.0 ng/ml after GHRH; 3.0 +/- 1.7 ng/ml after SRIF and 3.2 +/- 2.0 ng/ml after placebo). SRIF failed to substantially attenuate the nocturnal GH release. Nocturnal cortisol secretion was blunted after GHRH but remained unaffected by SRIF (61.4 +/- 12.9 ng/ml after placebo; 46.6 +/- 19.7 ng/ml after GHRH and 70.8 +/- 12.6 ng/ml after SRIF). Quantitative sleep EEG staging showed a significant increase in SWS after GHRH administration but no change after SRIF (percent spent in SWS per night: 14.0 +/- 5.6 after placebo, 20.2 +/- 6.6 after GHRH and 15.1 +/- 8.2 after SRIF). Application of SRIF was accompanied by a trend toward increased REM density. The effects of episodic GHRH administration upon SWS, GH and cortisol secretion were opposite to those previously reported for corticotropin-releasing hormone, which supports the view that neuroregulation of human sleep involves an interaction of central GHRH and corticotropin-releasing hormone.

Adult↗
PubMedDate not supplied

Functional properties of deoxycorticosterone and spironolactone: molecular characterization and effects on sleep-endocrine activity.

Adrenal steroid hormones are capable of interfering with a variety of behavioral phenomena including sleep. The mechanisms appear to involve effects at the cell membrane as well as nuclear actions mediated by intracellular mineralo- and glucocorticosteroid receptors (MR and GR). We employed the MR agonist deoxycorticosterone (DOC) and the MR antagonist spironolactone (SP) to study the role of MRs in the regulation of human sleep. We also tested whether the effects of DOC upon the sleep EEG and nocturnal hormone secretion (growth hormone and cortisol) are compatible with those predicted for its major metabolite tetrahydro-DOC (THDOC): electrophysiological and animal experiments had suggested that THDOC would act as a hypnotic via positive modulation of the GABAA receptor. Because neither DOC nor SP affected the sleep EEG substantially, the involvement of MRs in the regulation of sleep needs further study. The sleep-endocrine data showed a suppressive effect of DOC upon plasma cortisol concentrations and an earlier occurrence of nocturnal GH maxima, which can be plausibly explained by GR or sigma receptor-mediated effects. Molecular characterization of DOC and SP confirmed a relatively strong effect of DOC upon transactivation via MR and no effect of SP on the GR-mediated transcription rate. In addition, the possibility that a low dose of the mineralocorticoid DOC may serve as a prodrug for the potential hypnotic THDOC is not supported by the current data.

Adult↗
PubMedDate not supplied

Sleep deprivation and bright light as potential augmenters of antidepressant drug treatment--neurobiological and psychometric assessment of course.

The present study was designed to investigate the clinical efficacy of trimipramine with adjunct sleep deprivation (SD) or bright light (BL) and to evaluate psychometric and neurobiological variables that might be of predictive value for treatment response. We used (1) the combined dexamethasone-corticotropin releasing hormone test (DEX-CRH test) to characterize alterations of the hypothalamic-pituitary-adrenal (HPA) system; (2) polysomnography to evaluate sleep disturbances; and (3) a standardized test battery to assess cognitive psychomotor functions after study initiation and after 5 weeks of treatment. The overall response rate (> or = 50% decrease in score on Hamilton Rating Scale for Depression [HRS]) was 55% (N = 42). The response rate in the group with trimipramine monotherapy (N = 14) was 79%, whereas in the groups with adjunct SD (N = 14) and BL (N = 14), respectively, it was only 43%. All three groups showed significant improvement at the end of the third week of treatment. Neither of the adjunct treatments hastened the onset of antidepressant action as measured by HRS. A significantly higher proportion of nonresponders than responders (p < .05) had HPA dysregulation, disturbed rapid eye movement (REM) sleep (REM latency, REM% first third of night) and decreased non-REM sleep (% stage 2). The non-responders showed significantly more corticotropin (ACTH) secretion after CRH stimulation in the DEX-CRH test than the responders and a less rapid normalization of the neuroendocrine dysregulation (cortisol secretion) (p < .01). In addition, REM latency was significantly shorter in the BL group than in the monotherapy group and estimated duration of illness significantly longer in the SD group than in the monotherapy group. REM latency, percentage of REM sleep during the first third of the total sleep period, percentage of non-REM sleep stage 2 and ACTH release after a DEX-CRH challenge predicted response across all three treatment groups. The neurobiological symptoms were unevenly distributed, among the three groups, thus creating heterogeneity in these measures. This heterogeneity may have contributed to the different treatment response rates as defined by psychopathology (HRS). In contrast, the neuropsychological tests and some of the sleep-EEG investigations revealed different response patterns for different groups: The onset of improvement in simple cognitive functions and in sleep continuity was earlier in the adjunct treatment groups. This study underlines the need for a multidimensional approach including use of neurobiological and neuropsychological measures to identify the therapeutic profiles of different treatment strategies and predictors of outcome.

Adrenocorticotropic Hormone↗
PubMedDate not supplied

Differential mood response to natural and synthetic corticosteroids after bilateral adrenalectomy: a case report.

A 48-year-old woman who had had a bilateral adrenalectomy for Cushing's syndrome developed severe psychotic symptoms that were unresponsive to psychotropic drugs as long as she was taking prednisone (PRED) as replacement therapy. However, after she was switched to a regimen of cortisol (CORT) and fludrocortone (FLUD) the psychopathology disappeared. Mechanisms related to the differences in the interaction of natural (e.g. CORT) and synthetic (e.g. PRED) corticosteroids with the central glucocorticoid and mineralocorticoid receptors may explain the different effects upon psychopathology.

Adrenalectomy↗
PubMedDate not supplied

Hypothalamic-pituitary-adrenal system function in patients with Alzheimer's disease.

The neuropathologic hallmarks of Alzheimer's disease (AD) are very prominent in the hippocampus, a brain site which is pivotal for the regulation of the hypothalamic-pituitary-adrenal (HPA) system. Thus, the combined dexamethasone-suppression/CRH-stimulation-test outcome in patients with AD was compared to that of healthy elderly controls to assess--with a more refined neuroendocrine challenge procedure--HPA function in AD. Cortisol secretion after dexamethasone (DEX) pretreatment and before CRH was increased in Alzheimer's patients and 21% of this group were DST-nonsuppressors. None of the healthy control subjects escaped DEX-induced suppression of cortisol. However, after additional CRH administration, AD patients released significantly less cortisol and ACTH than the control subjects. No correlations were found between any of the endocrine parameters and degree of severity of dementia. It is concluded that the DST part of the DEX/CRH test better reflects glucocorticoid feedback disturbances, probably at a suprapituitary level. The CRH part of the DEX/CRH-test outcome might indicate the loss of endogenous CRH-Arginine-Vasopressin (AVP) synergism of the HPA system of these patients.

Adrenocorticotropic Hormone↗
PubMedDate not supplied

Effect of sleep deprivation on neuroendocrine response to a serotonergic probe in healthy male subjects.

Neuroendocrine responses to stimulation with a selective serotonin reuptake inhibitor (citalopram) were measured to investigate the effects of all-night sleep deprivation on serotonergic function in healthy male subjects (n = 7). We studied citalopram-stimulated prolactin and cortisol plasma concentrations in a placebo-controlled cross-over protocol following sleep and sleep deprivation. Citalopram infusion (20 mg i.v. at 14:20-14:50 h) after a night of undisturbed sleep prompted robust increases in both plasma prolactin and cortisol concentrations. Following a night of sleep deprivation, by contrast, the citalopram-induced prolactin response was blunted, but the cortisol response was not significantly altered. This differential response pattern relates to the distinct pathways through which serotonin may activate the corticotrophic and the lactotrophic systems. While an unchanged cortisol response does not indicate (but also does not refute the possibility of) an altered serotonergic responsivity following sleep deprivation, the suppressed prolactin response could reflect a downregulation of 5-HT1A or 2 receptors. An alternative, not mutually exclusive, explanation points to the possibility that sleep deprivation activates the tubuloinfundibular dopaminergic system, the final inhibitory pathway of prolactin regulation.

Adult↗