Search PubMed⌕ Search

Biomedical subjects

W F Gattaz

Publications and source records attributed to W F Gattaz.

At least 55 records · Page 3Linked to original sources
PubMed1994

Basal ganglia abnormalities in tardive dyskinesia. Possible relationship with duration of neuroleptic treatment.

The purpose of the present study was to investigate CT abnormalities in tardive dyskinesia (TD) and to search for possible relationships with clinical data. A group of 30 psychotic patients (15 schizophrenic and 15 affective disorder) with TD was compared to a matched group of 30 psychiatric patients without TD and a matched group of 30 healthy controls. CT data were analyzed using two multivariate statistical methods [multidimensional scaling (MDS) and step-wise discriminant analysis]. MDS clearly separated both TD and non-TD groups from the healthy control group on the basis of CT parameters. Caudate left area reduction and left temporal sulci enlargement were the most important parameters that discriminated TD from non-TD patients. Only in TD-patients did caudate left area reduction and left temporal sulci enlargement correlate significantly with cumulative duration of psychiatric hospitalizations. The data of the present study support the findings of structural abnormalities in the caudate nucleus and in the temporal lobe of patients with TD. These abnormalities were especially marked in the left hemisphere. It is assumed that some factor related to longer psychiatric hospital treatment (e.g. neuroleptic intake) could account for these abnormalities.

Adult↗
PubMed1994

[Accelerated breakdown of membrane phospholipids in schizophrenia--implications for the hypofrontality hypothesis].

Phospholipase A2 (PLA2) is a key enzyme in the metabolism of membrane phospholipids. We and other authors (Noponen et al., 1993) reported on increased PLA2 activity in serum and plasma from schizophrenic patients as compared to healthy and psychiatric controls. This increment in PLA2 activity could be inhibited by neuroleptic therapy. The breakdown of membrane phospholipids by PLA2 produces cytotoxic products such as lysophosphatidylcholine (LPC). We found in an independent series of studies increased PLA2 activity, decreased membrane phospholipids and increased LPC concentrations in platelets from schizophrenics, suggesting an accelerated breakdown of membrane phospholipids in the disease. To clarify the effects of PLA2 in the brain we investigated the effects of intracerebral PLA2 injections on dopaminergic neurotransmission in rats using Ungerstedt's model of rotational behaviour. Circing behaviour induced by DA agonists after unilateral PLA2 injections into the substantia nigra pars compacta were recorded. One, three and five weeks after intranigral PLA2 injection apomorphine induced an ipsilateral rotation, indicating a long lasting inhibition of ipsilateral nigrostriatal dopaminergic pathway by PLA2 application. Taken together, our findings indicate that a) at least a subgroup of schizophrenic patients shows increased PLA2 activity and consequently an accelerated breakdown of platelet membrane phospholipids, and b) in animal experiments the intranigral application of PLA2 inhibited the dopaminergic activity. How could these findings be related to the biology of schizophrenia? In schizophrenia a reduced dopaminergic activity in the frontal cortex has been hypothesized. Recent spectroscopy studies reported on an accelerated breakdown of membrane phospholipids in the frontal cortex from schizophrenics.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1994

Temporal stability of auditory evoked potentials at different stimulation rates.

1. We determined the temporal stability of the N1 and P2 waves of the auditory evoked potentials (AEP) for twelve healthy subjects who were tested in two sessions separated by 2 to 63 days (mean = 25 days). AEP were obtained at two different stimulation rates (1/s and 0.3/s). In addition to wave amplitude and latency, the latency difference and the amplitude ratio between the two stimulation rates were calculated. 2. Mean amplitudes, latencies, latency differences and amplitude ratios were not significantly different between the two sessions. Pearson's correlation was significant only for N1 latency at the 1/s stimulation rate (r = 0.64, P = 0.02). 3. Factors such as arousal and other subjective states of the subjects, personality traits, as well as technical aspects of the examinations, may have influenced the temporal stability of the AEP.

Acoustic Stimulation↗
PubMed1994

The epidemiology of early schizophrenia. Influence of age and gender on onset and early course.

For the investigation of the early course of schizophrenia starting from onset, the standardised Interview for the Retrospective Assessment of the Onset of Schizophrenia was developed and validated. In a representative sample of 267 first-admitted German schizophrenics of a broad diagnosis from a population of 1.5 million, the age at which different diagnostic and onset definitions were satisfied, the symptoms at the time of the interview, and the accumulation of positive and negative symptoms until first admission were assessed. Comparison between the two sexes and three age groups yielded hardly any differences in the accumulation of symptoms and their course until first admission, except for a slightly shorter period of negative symptoms in young males and a slightly longer one in older women--which contradicts prevailing opinion. At the time of the interview, no significant sex differences were found with respect to the core symptoms of schizophrenia (negative and first-rank symptoms), but clear and substantial differences emerged in disease behaviour. The significantly higher age at first onset in women is explained, on the basis of animal experiments and a clinical study, by the neuromodulatory effect of oestrogen on D2 receptors and by a higher vulnerability threshold in women.

Adolescent↗
PubMed1993

Pain perception threshold in major depression.

Somatosensory perception threshold (SPT) and pain perception threshold (PPT) were studied in 16 patients with major depression, compared to the findings in an age-matched and gender-matched control group and related to the psychopathological state evaluated by means of the Hamilton Depression Scale. Perception thresholds were assessed by means of a noninvasive high-frequency electric skin stimulation. Absolute perception thresholds were increased in the patients. However, the relative pain perception threshold (RPPT = PPT: SPT) was significantly reduced. RPPT was positively correlated with retardation. It was negatively correlated with anxiety, suggesting that a reduction of pain perception thresholds in depressive patients may be attributed to anxiety and impaired stress-coping.

Adult↗
PubMed1993

REM sleep parameters in the discrimination of probable Alzheimer's disease from old-age depression.

Thirteen dementia of the Alzheimer type (DAT) patients and fifteen old-age major depressive disorder (OAD) patients were investigated by polysomnography. The sleep was recorded during two nights after a 1 week wash-out period of psychotropic drugs. No statistically significant differences between the two groups were found concerning sleep continuity or architecture. The amount of REM sleep was significantly lower in DAT in comparison with OAD patients (11.7% verses 18.5%). Also, total REM density as well as the density of the first REM period were significantly lower in the DAT compared with the OAD patient group (15.8% verses 32.5%, 14.9% verses 38.1%, respectively). REM latency did not differ between both groups. Because REM latency is known from other studies to be shortened in depressed patients due to a cholinergic hyperactivity, the opposite finding, i.e., prolongation of REM latency, was expected for DAT patients. This assumption, however, could not be confirmed in the present study. It is concluded that REM density may better differentiate between DAT and OAD.

Aged↗
PubMed1993

Vitamin E attenuates the development of haloperidol-induced dopaminergic hypersensitivity in rats: possible implications for tardive dyskinesia.

Chronic haloperidol treatment in rats results in behavioural supersensitivity to dopamine agonists. This mechanism has been suggested as a possible animal model for tardive dyskinesia. In the present study the simultaneous administration of vitamin E to chronic haloperidol treatment in rats prevented the development of behavioural supersensitivity to apomorphine. This finding suggest that the concomitant administration of vitamin E to neuroleptics might prevent the development of tardive dyskinesia in humans.

Animals↗
PubMed1993

Auditory evoked potentials in schizophrenic patients before and during neuroleptic treatment. Relationship to psychopathological state.

The auditory evoked potential (AEP) components N1 and P2 were investigated under a no-task condition in a group of 14 acutely ill unmedicated schizophrenic patients and compared with the findings in an age- and sex-matched control group. In the patients, N1 latency was significantly increased, P2 latency and N1-P2 interpeak latency were reduced. There were significant relationships between AEP parameters and the psychopathological state evaluated by means of the brief psychiatric ratings scale (BPRS). The N1 and P2 latencies were negatively correlated with the BPRS subscore "anergia" and positively correlated with "agitation". In 8 of the patients, a standardized neuroleptic treatment was started with 10 mg haloperidol/day. After 2 weeks of treatment, BPRS scores and N1 amplitude had significantly decreased. However, there was no relationship between BPRS improvement and N1 amplitude reduction. N1 latency in the unmedicated state was negatively correlated with subsequent therapeutic response measured as proportional improvement of the BPRS score within 2 weeks. Thus, N1 latency may be seen as a psychophysiological measure with prognostic applications.

Adult↗
PubMed1993

Assessment of tardive dyskinesia by means of digital image processing.

A wireless device for the assessment of tardive dyskinesia by means of digital image processing is presented. Four skin-cream dots placed around the subjects' mouth are recorded by a video camera. The image is passed to a framegrabber with a signal processor, where it is converted from analogue to digital. A fast spot-detecting algorithm implemented on the signal processor tracks the dots and passes the information to a personal computer where a Fourier transformation is performed to calculate the frequency spectrum of the movements. The device provided detailed information on the magnitude and on the frequencies of the movements. Data from a longitudinal investigation suggest a higher sensitivity and reliability than conventional rating scales to detect and evaluate abnormal perioral movements. The device might be useful for the early detection, for the longitudinal assessment (p.e. clinical trials) and in some cases for the differential diagnosis of tardive dyskinesia, thus providing a tool for both research and clinical purposes.

Algorithms↗
PubMed1992

A psychiatric unit in a general hospital in Brazil: predictors of length of stay.

The planning and organization of mental health care in developing countries frequently lacks empirical data. The World Health Organization recommended psychiatric brief inpatient programs in general hospitals for these countries as a cost-effective alternative to the traditional mental hospital. Length of hospital stay is a crucial factor in a cost-effective mental health care organization. In a newly organized psychiatric inpatient unit in a general teaching hospital in Brazil we investigated the influence of 16 socio-demographic and clinical variables on the length of stay. Distance from residence to hospital (P less than 0.10), clinical diagnosis (P less than 0.05) and religious affiliation (P less than 0.05) were significantly related to length of stay. Possible mental health care implications of this short stay program are discussed.

Adolescent↗
PubMed1992

MK-801 induced stereotypies in rats are decreased by haloperidol and increased by diazepam.

The effects of haloperidol and diazepam were investigated on stereotypies (wall contacts and turn rounds) induced by the non-competitive NMDA antagonist MK-801 in rats. Haloperidol (0.03, 0.10, 0.25 and 0.40 mg/kg body weight) caused a dose-dependent antagonism whereas diazepam (3.0 and 5.0 mg/kg) caused a dose-dependent agonism of the stereotypies induced by 0.30 mg/kg MK-801 (all drugs given intraperitoneal). Conversely, diazepam (5.0 mg/kg) given alone reduced significantly the number of spontaneous wall contacts and turn rounds. The paradoxial stimulation of MK-801 induced stereotypies by diazepam could be explained by a shift between positive and negative corticostriatothalamic feedback loops envolving GABAergic neurons in favour of the former.

Animals↗
PubMed1992

Hypofrontality on topographic EEG in schizophrenia. Correlations with neuropsychological and psychopathological parameters.

Topographic EEG was performed in 17 DSM-III-R schizophrenic patients and in 15 sex- and age-matched healthy controls. Eleven patients were first-onset (neuroleptic naive) schizophrenics. EEG band power was compared with psychopathology, neuropsychology and neurological soft signs. The EEG was recorded at 14 topographic locations monopolarly and movements of the eye and of the lid were monitored by two bipolar electro-oculogram (EOG) derivations, one vertical and one horizontal. A multivariate correction of EOG artefacts was performed based on regression analysis with respect to EOG channels. Schizophrenic patients showed higher mean and median power in most bands. These differences were marked in the delta band, in the fast alpha and beta bands, in particular at left frontal sites. Delta power at F7 was by far the best separating variable between schizophrenics and controls in a discriminant analysis. Significant positive correlations were found between the Brief Psychiatric Rating Scale scores "Anxiety-depression" and "Activation" and power in the fast bands and negative ones between "Anergia" and the beta bands. Positive significant correlations emerged between the total score in the Negative Symptoms Rating Scale and the amount of delta power, predominantly over the temporal region. Impairment in the Luria-Nebraska neuropsychological scores "Rhythm" and "Memory" correlated highly significantly with EEG band power. No correlations were found between neurological soft signs and EEG band power. Our results are in line with the hypothesis of a hypofrontality in schizophrenia. It is unlikely that these findings are an artefact of prior psychiatric treatment, as they were also observed in first-onset, neuroleptic naive schizophrenics.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1992

The deleterious effect of ocular artefacts on the quantitative EEG, and a remedy.

The effect of ocular artefacts on spectral EEG parameters is assessed statistically. These artefacts are caused by movements of the eyeball and/or of the lid. Further, methods for correcting ocular artefacts are presented and evaluated. This methodological study is based on data from an investigation comparing the EEG of schizophrenic patients (n = 17) with healthy controls (n = 15). Ocular artefacts are monitored by the bipolar vertical and the bipolar horizontal electro-oculogram (EOG). It is shown that the influence of ocular artefacts on the measured electrical activity in the frontal region is larger than the cerebral potentials which the EEG is ideally intended to record. The more frequent occurrence of blinks and eye movements in schizophrenic patients may lead to an artificial enhancement of slow frequency EEG power for schizophrenics and eventually "false significances". In contrast to this, we found more significant group differences when correcting for EOG artefacts than without it. This can be attributed to a very much inflated sample variability of the uncorrected EEG, due to the individually varying EOG power. We conclude that it may not be sufficient to select visually epochs for analysis that are considered artefact-free. Rather, one should monitor EOG artefacts and apply an appropriate correction.

Artifacts↗
PubMed1992

Abnormalities in serum concentrations of interleukin-2, interferon-alpha and interferon-gamma in schizophrenia not detected.

The hypothesis of an immunological defect in schizophrenia has been supported by reports on abnormal production of interleukin-2 (IL-2) and interferons (IFNs) in schizophrenic patients. In the present study we determined the serum concentrations of IL-2, IFN-alpha and IFN-gamma in 10 first onset, neuroleptic-naive schizophrenics, in 6 pretreated patients who were drug free (1 week to 2 years) at the time of the investigation and in 15 matched healthy controls. No IFN-alpha was detected in schizophrenics' and in control sera. No differences were found in IL-2 and IFN-gamma levels between schizophrenics and controls. Thus the present study failed to support the hypothesis of an immunological abnormality in schizophrenia on the basis of the determination of IL-2 and IFNs serum levels.

Adult↗
PubMed1992

[Estradiol inhibits dopamine mediated behavior in rats--an animal model of sex-specific differences in schizophrenia].

We found in a representative sample of 392 first hospital admissions for schizophrenia a higher mean age at onset in females by 3.2 to 3.9 years, whereas the lifetime risk was equal for both sexes. In males the rates of onset show a steep increase reaching the maximum value in the age group 15-24 years, followed then by a steady decrease. Females reach the first peak with a clear delay between 20 and 29 years. After the decrease a second smaller peak is observed consistently in females within the age group 45-49 years and over. After having excluded alternative explanations for this gender differences (for example, diagnosis artefacts, sociocultural factors), we hypothesized that the effect of oestradiol on the dopaminergic system enhances the vulnerability threshold for schizophrenia, which is lowered again during the menopause. Alternatively we assumed that testosterone reduces the vulnerability threshold and thus furthers the earlier onset of schizophrenia in males. We tested these hypotheses in animal models by investigating the effects of the gonadal hormones on haloperidol-induced catalepsy and on apomorphine-induced stereotypies in both neonatal and adult rats. Testosterone showed no clear influence on the tested dopamine-mediated behaviour. Oestradiol caused a significant reduction on both dopamine-agonist and dopamine-antagonist induced behaviour. These effects were stronger in neonatal animals. Since oestradiol caused a 2.8-fold reduction of dopamine receptor affinity for sulpiride, we assumed that the behavioural changes caused by oestradiol were accounted for by a down-regulation of the dopaminergic system.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗