Biomedical subjects

W Rossbach

Publications and source records attributed to W Rossbach.

8 recordsLinked to original sources

PubMed2004

Subchronic effects of olanzapine on sleep EEG in schizophrenic patients with predominantly negative symptoms.

BACKGROUND: It is well known that sleep disturbance is an integral symptom of schizophrenia. In recent studies, a deficit of delta sleep has been observed in schizophrenic patients. Antipsychotic drugs with serotonin (5-HT2) receptor-antagonistic properties are considered to have delta sleep promoting effects. We have investigated the effects of subchronic olanzapine treatment on sleep EEG in schizophrenic patients. METHODS: The effects of administration of olanzapine (15 to 20 mg) on sleep were studied for four weeks in 10 male, drug-free patients suffering from schizophrenia with predominantly negative symptoms. Conventional sleep EEG parameters were investigated at baseline and after treatment with olanzapine for four weeks. Additionally, spectral power analysis of the EEG signal in distinct frequency bands was computed for different sleep stages. Psychopathology (PANSS, HAMD-17, HAMA) and side effects were assessed weekly. RESULTS: All patients improved, as measured by PANSS global scores. Compared to baseline, there was a significant improvement of parameters of sleep efficiency and an increase of delta sleep as well as REM sleep. Regarding spectral power values, no significant differences between baseline and treatment conditions were found. CONCLUSIONS: Sleep improvement was due to parameters of sleep efficiency and delta sleep, which may be related to serotonin antagonistic properties of olanzapine.

Adolescent↗

PubMed2000

[Evaluation of standardized training for the "Positive and Negative Syndrome Scale" (PANSS)].

The present analysis comprises 3 studies on the interrater reliability of the Positive and Negative Syndrome Scale for Schizophrenia (PANSS; German version). To our knowledge this is the first empirical report on interrater reliability and on results of rater training of the German version of the PANSS despite the widespread use of the scale. In a total of 47 training participants with different clinical experience standardized PANSS rater training was carried out and subsequently evaluated. Therefore, concordance rates with an expert standard (C) and weighted coefficients kappa (kappa W) were calculated. As a main outcome of the studies, at least 3 training sessions were necessary but also sufficient to reach acceptable interrater reliability of the PANSS (C > 80%, kw > 0.60). In training participants with low psychiatric experience the level of interrater reliability of schizophrenic negative symptoms did not reach the results of positive symptoms after the training. Despite some conceptual limitations with respect to negative symptoms, the German version of the PANSS seems highly suitable to assess a broad spectrum of schizophrenic psychopathology in a reliable and economic manner. The present results also underline the practicability of our recommendations for conducting PANSS rater training in the clinical and scientific field as part of quality control and quality assurance in psychopathological assessment.

Adult↗

PubMed2000

Effects of subchronic paroxetine administration on night-time endocrinological profiles in healthy male volunteers.

To evaluate the subchronic effects of paroxetine, a selective serotonin reuptake inhibitor, on nocturnal endocrinological profiles, eight healthy male volunteers with no personal or family history of a psychiatric or neurological disease were administered paroxetine (30 mg/day) or placebo in a double-blind cross-over design. Drugs were given as a single dose at 10:00 h for a period of 4 weeks each. Between days 21 and 28 of each treatment period, sleep EEG was registered for four consecutive nights from 23:00 to 07:00 h. During the last night, hormonal profiles for prolactin, growth hormone (GH), cortisol, corticotropin (ACTH), luteinizing hormone (LH), testosterone and melatonin were determined, and area-under-the-curve values were calculated. None of the endocrinological parameters revealed any statistically significant changes. A trend could be found for an increased cortisol production under paroxetine (P = 0.069). ACTH, LH, and melatonin showed slight and non-significant decreases. Prolactin release was only marginally elevated (+7%). The mean sleep onset GH release (as measured for a time period of 180 min after sleep onset) was decreased by about 30% under paroxetine. However, statistical significance could not be reached. For hGH, there was a delayed mean GH-peak under paroxetine. Nocturnal testosterone secretion remained almost unaltered. The lack of significant endocrinological alterations might be partially explained by both adaptational phenomena under subchronic treatment conditions and the extended time span between the single morning dose and the registration period, respectively.

Adrenocorticotropic Hormone↗

PubMed1998

Evaluation of standardized rater training for the Positive and Negative Syndrome Scale (PANSS).

The Positive and Negative Syndrome Scale (PANSS) is employed increasingly for the evaluation of therapeutic outcome in studies on schizophrenia. Rater training is important to improve the concordance and accuracy of ratings; however, there are no established guidelines for carrying out such training. We conducted rater training, under clinical conditions, of psychiatrists and clinical psychologists who were rather unfamiliar with the PANSS. Based on videotapes of PANSS interviews, all participants were trained during five successive standardized weekly sessions. The results were analyzed with respect to conventional criteria of concordance with standard expert ratings and interrater reliability. The main objective was to evaluate the number of training sessions which are necessary and sufficient to achieve acceptable PANSS rating results. Additionally, differences in training outcome for positive, negative and general psychopathological symptoms and between subgroups of different clinical and PANSS experience were considered. After three weekly sessions, satisfactory concordance of about 80% of clinicians on the PANSS total scale was obtained. However, in comparison with the positive and general psychopathological subscales, the PANSS negative-symptom subscale yielded somewhat less satisfactory results, with about 70% of the raters achieving sufficient accuracy. Intraclass correlations corroborated these findings. No substantial differences in training outcome were found between subgroups of different clinical and PANSS experience. We conclude that at least three standardized PANSS training sessions are recommended to obtain satisfactory accuracy of ratings.

Adult↗

PubMed1998

Conventional and spectral power analysis of all-night sleep EEG after subchronic treatment with paroxetine in healthy male volunteers.

Paroxetine is a selective and potent serotonin reuptake inhibitor with reported antidepressant properties. Since changes in the regular sleeping pattern were described as side effects under treatment with paroxetine, the impact of the drug on the sleep architecture is of major interest. The present study addressed the question of subchronic effects of paroxetine medication (30 mg/day) in eight healthy male volunteers in a double blind, placebo-controlled crossover-design. Conventional sleep EEG parameters and additionally computed spectral power analysis based on FFT of 20-s time epochs in the delta, theta, alpha, beta and gamma frequency range for different sleep stages after 4 weeks of treatment were investigated. Subchronic paroxetine administration in healthy subjects led to a prolonged REM latency and a decrease in the number of REM phases, whereas sleep efficiency, total sleep time, sleep onset latency, number of awakenings, and awake during sleep period time were not altered by paroxetine medication. Moreover, we could not detect any alterations of the spectral power values in certain frequency bands during NREM or REM sleep following subchronic paroxetine medication.

Adult↗

PubMed1997

Analysis of sleep EEG microstructure in subchronic paroxetine treatment of healthy subjects.

Paroxetine is a selective and potent serotonin reuptake inhibitor and its efficacy for the treatment of depression has been proven. Under acute and subchronical treatment regimens, disturbances of the regular sleep pattern are a reported side effect of the drug. The present study was therefore performed to investigate the impact of subchronic treatment with the selective serotonin reuptake inhibitor paroxetine on the microstructure of the sleep EEG. The study especially addressed the question of subchronic effects of paroxetine medication (30 mg/day) in eight healthy male volunteers in a double blind, placebo-controlled crossover design. Conventional sleep EEG parameters and a spectral power analysis for different sleep stages after 4 weeks of treatment were computed. Additionally, the correlation of certain EEG rhythms across the night was calculated in order to detect subtle dynamical EEG alterations, not necessarily obvious when regarding conventional EEG analysis. Although we could not detect any alterations of the spectral power values in certain frequency bands either during NREM nor during REM sleep following subchronic paroxetine medication, the dynamical EEG attributes across the night revealed a significant enhancement of the correlation between certain EEG rhythms mainly during NREM sleep.

Adult↗

PubMed1990

Computerized ordering of experimental animals and test authorization.

The authorization procedure required by law in Switzerland and the internal set-up at Roche for acquiring experimental animals has made a computerized system for monitoring authorizations and animal deliveries essential. The INQUIRE software program, which can be run on the central computer, was used to set-up databases with information on all personnel who place orders and perform experiments (PERI), authorization matters (BEWI), orders (ORDR), deliveries (SPED), animal species (SPEC), animal strains (STRE), populations (POPU) and the management of various data (BARA). The authorizations database (BEWI) permits sequential searches on specific questions. The animals ordered in the ORDR database are constantly updated in BEWI, thus ensuring that the authorized animal quotas are not exceeded. Expiry of an authorization or an unregistered experimenter will come to light in the course of the plausibility study. Through ORDR the experimenter has a good overview of the animals that he has ordered or have been ordered for him, and he can select the most appropriate strain or population for his studies in STRE or POPU, which contain data on the genetic and physiological characteristics as well as the breeding and keeping of all sublines and stocks. Realization of the IFIS project has made it a simple matter to keep a check on the legal requirements pertaining to animal experimentation and to update the information and evaluate the entire stock of data at any time.

Animals↗

PubMed1989

Consistency of laboratory animal food following incubation prior to autoclaving.

In this study the conventional autoclaving technique was modified by incubating the food overnight prior to autoclaving. This treatment resulted in a markedly improved consistency of the food pellets, comparable with that of untreated food. The modified autoclaved food did not adhere to the walls of feeders or clog the transport passage. Furthermore, the losses in thermolabile vitamins resulting from this treatment were the same as those resulting from conventional autoclaving.

Animal Feed↗