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P Danos

Publications and source records attributed to P Danos.

At least 19 recordsLinked to original sources

Eeg alpha rhythm and glucose metabolic rate in the thalamus in schizophrenia.

Positron emission tomography with uptake of [(18)F]fluorodeoxyglucose (FDG) and quantitative EEG were simultaneously performed in 18 medication-free patients with schizophrenia and in 13 normal volunteers. Subjects performed the Continuous Performance Task (CPT) during FDG uptake. Correlations were calculated between alpha power during the CPT and glucose metabolic rate (GMR) in thalamic regions and between alpha power during the CPT and GMR in occipital cortices. Regression analyses were used to describe the prediction of GMR in the occipital cortices and in the thalamic regions of occipital alpha power. In normal controls, we found (1) significant negative correlations between absolute alpha power and GMR in the left occipital cortex, (2) significant positive correlations between normalized alpha power and GMR in the right and left lateral thalamus and (3) combined effects of GMR in the thalamic regions and the occipital cortices on alpha power, which accounted for 98% of the variance of alpha power. In patients with schizophrenia, we found no significant correlations between alpha power and GMR in the occipital cortices or between alpha power and GMR in the thalamic regions. Correlation coefficients between absolute alpha power and GMR in the left occipital cortex and between normalized alpha power and GMR in the left lateral thalamus were significantly different in normal subjects compared to schizophrenic patients. The present findings provide evidence for involvement of the thalamus in the generation of alpha rhythm in humans. Furthermore, the present results suggest differences in thalamocortical circuits between normal controls and schizophrenic subjects.

Adult↗

Delayed onset of late movement-related cortical potentials and abnormal response to lorazepam in catatonia.

Catatonia is a psychomotor syndrome with an inability to execute and terminate movements completely, leading consecutively to akinesia and posturing, which both respond almost immediately to benzodiazepines, i.e. gaba-potentiators like lorazepam. However, pathophysiological mechanisms of cortical motor and gaba-ergic dysfunction remain unclear. We therefore investigated movement-related cortical potentials (MRPs) and movement kinematics during a motor task before and after lorazepam. Ten akinetic catatonic patients were compared with 10 psychiatric (similar age, sex, medication, and underlying psychiatric disease but without catatonic syndrome) and 20 healthy controls. MRPs from frontal (F), central (C), and parietal (P) sites were recorded to obtain measures of early and late readiness potential and movement potential. Kinematic measures included parameters for amplitude of movements, peak velocity, average duration of movements, elevation angle, and angle velocity. The motor task consisted in self-initiated extension of the right index finger. All catatonic and psychiatric control patients received intravenous lorazepam (1mg), whereas healthy controls were subjected to a placebo-controlled (10 received lorazepam, 10 received placebo) double-blind study design.Catatonics showed a significantly delayed onset of late readiness and movement potential in central electrodes (Cz, C3) compared with psychiatric and healthy controls. This delayed onset correlated significantly with catatonic motor symptoms and movement duration. Lorazepam led to significantly stronger delays in onset of late readiness potential in left fronto-parietal (F3, C3, P3) electrodes in catatonic patients than in psychiatric and healthy controls. It is concluded that delayed latencies in late MRP components in catatonic patients may reflect their inability to execute and terminate movements completely. Differential and stronger response to lorazepam in catatonia suggests dysfunction in inhibitory control of cortical motor function with increased gaba-ergic sensitivity.

Adult↗

Can chronic neuroleptic treatment promote sleep disturbances in elderly schizophrenic patients?

It has been proposed that sleep disturbances, especially reduced delta sleep, are related to a poor outcome in schizophrenia. To determine whether long-term treatment with neuroleptics can promote sleep disturbances by increasing the risk of a nocturnal myoclonus syndrome (NMS) (=periodic movements in sleep) related insomnia, we performed all-night polysomnography in 10 chronically ill schizophrenic patients who had been under neuroleptic therapy for a mean of 27 years. NMS-related insomnia was detected in all 10 patients. Potential pathophysiological relationships between long-term neuroleptic therapy and NMS occurrence are discussed. Our findings suggest that long-term administration of neuroleptics favours the appearance of insomnia.

Aged↗

Low and infrequent expression of nitric oxide synthase/NADPH-diaphorase in neurons of the human supraoptic nucleus: a histochemical study.

The gas nitric oxide is a messenger in brain signaling. In the hypothalamo-hypophyseal system nitric oxide is involved in the control of the expression and/or release of peptide hormones (corticotropin-releasing hormone, gonadotropin-releasing hormone, vasopressin and oxytocin). Nitric oxide synthase (NOS), the enzyme generating nitric oxide, is abundantly present in the magnocellular nuclei of the rat hypothalamus. Its localization in the human hypothalamus is less well studied. Hence, we investigated the anatomical distribution of neuronal nitric oxide synthase in the human supraoptic nucleus by use of immunohistochemical and enzyme histochemical techniques. The immunohistochemical localization of NOS was studied in 31 matched human hypothalami (13 control cases, eight depressed patients and ten schizophrenics). NADPH-diaphorase studies were carried out on seven additional hypothalami (three normal brains, four schizophrenics). Apparent inter-individual differences exist with regard to the occurrence of the enzyme in supraoptic neurons. In a majority of cases no immunostaining or histochemical reaction for the enzyme was observed. In seven cases (three controls, two schizophrenics, two depressives) a population of nitrergic nerve cells was seen in the dorsomedial part of the nucleus. This group of cells also stained for NADPH-diaphorase. Also, there were a few NOS-immunopositive neurons scattered throughout the nucleus. Additionally, thin NADPH-diaphorase positive fibers were observed to cross the nucleus. Our data show that, unlike the rat, the human supraoptic nucleus contains only a small number of nitrergic neurons. No correlation was found between the expression of the enzyme in supraoptic neurons and the psychiatric status of the patients.

Aged↗

Right lower prefronto-parietal cortical dysfunction in akinetic catatonia: a combined study of neuropsychology and regional cerebral blood flow.

BACKGROUND: Catatonia is a psychomotor syndrome that can be characterized by behavioural, affective and motor abnormalities. In order to reveal further underlying pathophysiological mechanisms of psychomotor disturbances in catatonia we investigated neuropsychological function and regional cerebral perfusion (r-CBF) in a combined study. METHODS: Ten catatonic patients were investigated with Tc-99mECD brain SPECT and compared with 10 psychiatric (similar age, sex, medication and underlying psychiatric diagnosis but without catatonic syndrome) and 20 healthy controls. Neuropsychological measures included tests for general intelligence, attention, executive functions and right parietal visual-spatial abilities. Correlational analyses were performed between neuropsychological measures, catatonic symptoms and r-CBF. RESULTS: Catatonic patients showed a significant decrease of r-CBF in right lower and middle prefrontal and parietal cortex compared with psychiatric and healthy controls as well as significantly poorer performance in visual-spatial abilities associated with right parietal function. Correlational analysis revealed significant correlations between visual-spatial abilities and right parietal r-CBF only in psychiatric and healthy controls but not in catatonic patients. In contrast, attentional measures correlated significantly with motor symptoms, visual-spatial abilities and right parietal r-CBF in catatonia only but not in psychiatric or in healthy controls. CONCLUSION: Findings are preliminary but suggest right lower prefronto-parietal cortical dysfunction in catatonia, which may be closely related to psychomotor disturbances.

Adult↗

Disposition of haloperidol pyridinium and reduced haloperidol pyridinium in schizophrenic patients: no relationship with clinical variables during short-term treatment.

In an open clinical trial, serum concentrations of haloperidol pyridinium (C(HP+)) and reduced haloperidol pyridinium (C(RHP+)), as well as haloperidol (CH) and reduced haloperidol (C(RH)), were measured in 57 schizophrenic and schizoaffective inpatients during 6 weeks of short-term treatment. Psychopathology was monitored with the Brief Psychiatric Rating Scale (BPRS), and extrapyramidal adverse effects were assessed with the Extrapyramidal Symptom Rating Scale (EPS). Significantly linear relationships were found between haloperidol dose (D) and pyridinium metabolite serum concentrations, as well as between C(H) and the pyridinium metabolite serum concentrations. C(HP+) (range, 0.2-4.9 ng/mL) and C(RHP+) (range, 0.03-6.23 ng/mL) were low compared with C(H) and C(RH), being as mean values approximately 7% and 14% of C(H) and C(RH), respectively. Additionally, the values of C(RHP+) and the slope of the correlation of C(H) with the C(RHP+)/C(HP+) ratio were considerably lower than in a previous report of long-term treatment with haloperidol. This is explained by the shorter time of treatment of the present study. Carbamazepine comedication was found to not influence relative pyridinium metabolite serum concentrations C(HP+)/D and C(RHP+)/D. However, the aromatization ratios of haloperidol (C(HP+)/C(H)) and reduced haloperidol (C(RHP+)/C(RH)) were increased by concomitant carbamazepine. As the main result, no relationships between the pyridinium metabolite serum concentrations and clinical variables (BPRS change, EPS, dose of biperiden) were detected. For instance, the aromatization ratios C(HP+)/C(H) and C(RHP+)/C(RH) did not predict clinical improvement or extrapyramidal adverse effects. Therefore, no confirmation of the "pyridinium hypothesis," which suggests haloperidol pyridinium metabolites to be the origin of adverse effects and decreased therapeutic effect, can be derived from this study. However, the authors emphasize that pyridinium metabolites cannot be excluded as the origin of decreased therapeutic effect in long-term treatment and of adverse effects not investigated in the present study, such as tardive dyskinesia. Finally, it is concluded that the serum concentration of the parent drug remains the main variable of interest in the therapeutic drug monitoring of haloperidol during short-term treatment.

Adult↗

Impairment in visual-spatial function in catatonia: a neuropsychological investigation.

Catatonia is a psychomotor syndrome with motor and behavioral abnormalities which may be due to alterations in fronto-parietal cortical function. We therefore investigated neuropsychological tasks (attention, executive, visual-spatial, working memory) associated with frontal and parietal cortical function. Thirteen catatonic patients, diagnosed as catatonic according to criteria by Rosebush and Bush, were compared with 13 psychiatric non-catatonic controls (matched with regard to underlying psychiatric diagnosis, age, sex, and medication), and 13 age- and sex-matched healthy controls. Catatonics showed significantly poorer performances and different neuropsychological intercorrelation patterns in visual spatial object perception (VOSPobject) than psychiatric and healthy controls. In addition, we found significant correlations between catatonic symptoms, visual-spatial abilities, and attentional measures (i.e., d2, CWI). Catatonia was characterized by specific visual-spatial deficits which are related to attentional abilities and right parietal cortical function. The data suggest attentional-motor and fronto-parietal dysfunction in catatonia, a conclusion which should be considered as preliminary, however, due to the small sample size.

Adult↗

Tyrosine hydroxylase immunoreactivity in the locus coeruleus is reduced in depressed non-suicidal patients but normal in depressed suicide patients.

Noradrenergic neurons of the locus coeruleus (LC) have been implicated in the neurobiology of depression and suicidal behavior. The current postmortem study determined numbers of noradrenergic neurons by immunostaining the synthesizing enzyme tyrosine hydroxylase in the LC of 12 non-elderly depressed patients with a mood disorder as compared to 12 age- and sex-matched normal controls. Six patients were suicide victims, the other six patients died of natural causes. Non-suicidal patients had fewer neurons immunoreactive for tyrosine hydroxylase (TH-ir) than suicide victims or controls. No difference appeared between the number of TH-ir neurons in suicide patients and controls. Numbers of pigmented LC neurons were equal in patients and controls. The differences of TH-immunoreactivity could neither be attributed to drug influences nor to polarity of depressive disorder (i.e., unipolar/bipolar). Numbers of TH-ir neurons correlated positively with mean doses of tri- or tetracyclic antidepressants. Results of this study suggest a presynaptic noradrenergic deficit of the LC in depressed non-suicidal patients. Indirect evidence is provided that suicide is not related to decreased noradrenergic function and that traditional antidepressants may enhance noradrenergic activity of the LC in depressed patients.

Adult↗

Unipolar-bipolar dichotomy of mood disorders is supported by noradrenergic brainstem system morphology.

BACKGROUND: The biological basis of unipolar-bipolar dichotomy of mood disorders was investigated in this postmortem study by morphological comparison of the locus coeruleus (LC) as the main source of noradrenergic transmission in the brain. METHODS: Numbers and the rostro-caudal as well as ventro-dorsal distribution of neuromelanin-containing neurones in the LC were determined in brainstem of 12 patients with bipolar disorder (n = 6) or major depression (n = 6), and 12 normal comparison subjects. RESULTS: Bipolar patients had significantly more neurones on both sides of the LC as a whole than patients with major depression. Topographical analysis revealed that this difference was restricted to the rostral two thirds and the dorsal part of the LC, in which bipolar patients showed at least a trend to higher neurone numbers as compared to unipolar patients or to controls. LIMITATIONS: Small case numbers. CONCLUSIONS: Results suggest differences of innervation arising from the LC of bipolar patients as compared to patients with major depression. These first data of brainstem transmitter system morphology in unipolar and bipolar disorder are in line with neuroanatomical studies of other brain regions indicating a biological basis of the unipolar-bipolar dichotomy of mood disorders.

Adult↗

Regional and cellular distribution of neural visinin-like protein immunoreactivities (VILIP-1 and VILIP-3) in human brain.

Neural visinin-like proteins (VILIPs) are members of the neuronal subfamily of intracellular EF-hand calcium sensor proteins termed the NCS family, which are thought to play important roles in cellular signal transduction. While numerous studies suggest a wide but uneven distribution of these proteins in rat and chicken brain, their location in, and possible significance for, the human brain, remains to be established. We used specific polyclonal antisera to map the human brain for VILIP-1 and VILIP-3 immunoreactivities. VILIP-1 was detected in cortical pyramidal cells and interneurons, septal, subthalamic and hippocampal neurons (subfields CA1 and CA4 pyramidal cells and especially hilar interneurons) as well as in cerebellar Golgi, basket, granule, stellate and dentate nucleus neurons. Purkinje cells were free of immunoreaction. VILIP-3 was more restricted in its distribution. It was identified in cerebellar Purkinje cells and a subpopulation of granule neurons. Further, neurons belonging to different nuclei of the brain stem and multiple subcortical nerve cells stained for visinin-like protein 3. A weak immunoreaction appeared in cortical and hippocampal neurons. Intracellularly the immunoreactivity appeared in the perikarya, dendrites and some axons. Sometimes, immunostaining was found in the neuropil. Glia did not express visinin-like proteins. Our findings support, from a neuroanatomical viewpoint, the idea that these calcium sensor proteins may be of relevance for neuronal signalling in the human CNS.

Animals↗

Decreased density of GABA-A receptors in the left sensorimotor cortex in akinetic catatonia: investigation of in vivo benzodiazepine receptor binding.

OBJECTIVES: Catatonia is a psychomotor syndrome with concomittant akinesia and anxiety which both respond almost immediately to benzodiazepines such as lorazepam. The benzodiazepine receptor distribution was therefore investigated in akinetic catatonia with single photon emission tomography (SPECT) using iodine-123-iomazenil ((123) I Iomazenil). METHODS: Ten akinetic catatonic patients, 10 psychiatric controls (similar age, sex, medication, and underlying psychiatric diagnosis but without catatonic syndrome), and 20 healthy controls were investigated with SPECT 2 hours after injection of (123) I Iomazenil. To exclude potential effects of cerebral perfusion (r-CBF) r-CBF was additionally investigated with Tc-99mECD SPECT. RESULTS: Catatonic patients showed significantly lower iomazenil binding and altered right-left relations in the left sensorimotor cortex compared with psychiatric (p<0.001) and healthy (p<0.001) controls. In addition, there was significantly lower r-CBF in the right lower prefrontal and parietal cortex in catatonia whereas in the left sensorimotor cortex no differences in r-CBF between groups were found. Catatonic motor and affective symptoms showed significant correlations (p<0.05) with benzodiazepine binding in the left sensorimotor cortex as well as with right parietal r-CBF. CONCLUSIONS: Reduced iomazenil binding suggests decreased density of GABA-A receptors in the left sensorimotor cortex in akinetic catatonia. In addition to reduced GABA-A receptor density in the left sensorimotor cortex the parietal cortex seems to be involved in pathophysiology of catatonic symptoms. It is concluded that, considering results from correlation analyses, both emotional and motor symptoms in catatonia seem to be closely related to left sensorimotor and right parietal alterations.

Adult↗

Reduced volume of limbic system-affiliated basal ganglia in mood disorders: preliminary data from a postmortem study.

Volumes of basal ganglia in postmortem brains of 8 patients with mood disorders and 8 control subjects without neuropsychiatric disorder were determined. Morphometry of serial whole-brain sections under the control of postmortem artifacts revealed reduced volumes of the left nucleus accumbens (-32%, P = 0.01), the right and left external pallidum (-20%, P = 0.04), and the right putamen (-15%, P = 0.04) in the patient group compared with the control group. These results suggest that, in particular, the limbic loop of the basal ganglia involving the nucleus accumbens and the pallidum is affected in mood disorders.

Adult↗

Morphometric studies of the entorhinal cortex in neuropsychiatric patients and controls: clusters of heterotopically displaced lamina II neurons are not indicative of schizophrenia.

Subtle cytoarchitectural abnormalities of the rostral entorhinal cortex have been reported to be characteristic for schizophrenics. A main finding was the heterotopic displacement of clusters of lamina II neurons (which appeared morphologically immature) into layer III. Recent findings suggesting a considerable cytoarchitectural heterogeneity of the normal entorhinal cortex renewed interest in this problem and prompted the question of the extent to which 'aberrantly' located cell clusters are really disease-related. Being blind to the clinical diagnosis, we analyzed quantitatively the amount of entorhinal heterotopias in schizophrenics (n = 31), controls (n = 45) and depressive patients (n = 7). It was revealed that heterotopic cell clusters occurred in schizophrenics and controls with roughly the same frequency (amount of clusters per section). In depressive, there were significantly more heterotopias than in controls (right hemisphere). Our data show that heterotopias are common to the rostral part of the human entorhinal cortex and are not a suitable neuroanatomical marker of schizophrenia.

Adult↗

Schizophrenia and anteroventral thalamic nucleus: selective decrease of parvalbumin-immunoreactive thalamocortical projection neurons.

This study was designed to examine possible anatomical changes of thalamocortical circuits in schizophrenics. Previous immunocytochemical studies have shown that parvalbumin, a calcium-binding protein, occurs in thalamocortical projection neurons, but not in GABAergic interneurons in the anteroventral thalamic nucleus (AN). Using parvalbumin-immunocytochemistry we investigated the densities of thalamocortical projection neurons in the AN of schizophrenic cases (n = 12) and controls (n = 14). The densities of all neurons in the AN were estimated by Nissl-staining. The majority of thalamocortical projection neurons in AN were identified by parvalbumin-immunoreaction. Significantly reduced densities of thalamocortical projection neurons were estimated in the right (P = 0.003) and left AN (P = 0.018) in schizophrenic subjects. The densities of all neurons in right and left AN were also diminished in schizophrenics; however, these decreases did not reach statistical significance. The reductions of parvalbumin-positive thalamocortical projection neurons were not correlated with the length of disease, this finding supporting the neurodevelopmental etiology of structural abnormalities in schizophrenia.

Adult↗

Cerebral vasoconstriction during sustained ventricular tachycardia induces an ischemic stress response of brain tissue in rats.

Arterial hypotension can cause cerebral ischemia when the autoregulation of the cerebral circulation is exhausted. We hypothesized that sudden cerebral vasoconstriction induced by moderate hypotensive, but hemodynamically stable, sustained ventricular tachycardias (MHT-VT) further compromises cerebral blood flow (CBF) and induces an ischemic stress response of the brain. CBF-measurements and morphological studies were performed without and with blockade of alpha-adrenergic receptors in order to determine the impact of MHT-VF on brain perfusion and brain tissue. Using a model of MHT-VT, CBF was measured with colored microspheres in 71 rats during control conditions. after the onset of MHT-VT, after the onset of moderate hypotensive hypovolemia (MHH), and after additional non- selective (alpha-blockade with phentolamine and selective alpha1-blockade with prazosin, respectively (0.2-0.4 mg/kg body weight). Plasma catecholamine concentrations were measured in 18 additional rats during control conditions. during MHT-VT and during MHH. The occurrence of heat shock protein (hsp) 72 and activated microglia in the brain was analysed in 18 additional rats in controls, after MHT-VT and MHH. After 20 min of the respective induced hypotension, control conditions were restored for a period of 8 h, by stopping VT or by infusion of isotonic saline solution. CBF was 0.98+/-0.16 (mean+/-S.D.) ml/g/min during control conditions at an arterial pressure of 118+/-13 mmHg, 0.50+/-0.05 ml/g/min (P<0.05 v control) during MHT-VT (76+/-4 mm Hg) and 0.75+/-0.14 ml/g/min (P<0.05 v control and v MHT-VT ) during MHH (71 +/- 8 mm Hg). CBF was better preserved with non-selective alpha-blockade during MHT-VT (0.78+/-0.15 ml/g/min, P<0.05 v MHT-VT and control) as well as with selective alpha1-blockade (0.67+/-0.08 ml/g/min, P<0.05 v MHT-VT and control). Plasma catecholamines were elevated during MHT-VT (P<0.05 v control) but not during MHH (P = N.S. v control). hsp 72 and activated microglia were found in hippocampal regions only after MHT-VT (P<0.05 v control and MHH). These morphological changes were prevented by non-selective alpha-blockade. Stable sustained MHT-VT further reduce the already compromised CBF leading to morphological alterations in the brain which are characteristic of an early ischemic stress response. alpha-Blockade prevents alpha1-adrenergic vasoconstriction and attenuates cerebral hypoperfusion.

Adrenergic alpha-Antagonists↗

Nitric oxide synthase-containing neurons in the human hypothalamus: reduced number of immunoreactive cells in the paraventricular nucleus of depressive patients and schizophrenics.

The neuroanatomical distribution of nitric oxide synthase-immunoreactive neurons was investigated in post mortem hypothalami of 10 patients suffering from schizophrenia, eight patients with depression and 13 matched control cases. Neuronal nitric oxide synthase containing nerve cells were detected in several hypothalamic nuclei including the medial preoptic region, the ventromedial, infundibular and suprachiasmatic nuclei and the lateral hypothalamus. The vast majority of hypothalamic nitric oxide synthase-immunoreactive neurons was found to be located in the paraventricular nucleus. Both magno and parvocellular paraventricular neurons contained the enzyme. A small subset of immunoreactive parvocellular paraventricular neurons co-expresses corticotropin-releasing hormone. The supraoptic nucleus did not contain nitric oxide synthase-immunoreactive neurons. Cell counts of paraventricular nitric oxide synthase-positive neurons in controls, schizophrenics and depressed patients revealed a statistically significant reduction of cell density in the right paraventricular nucleus of depressed patients and schizophrenics as compared to controls. The total amount of nitric oxide synthase-immunoreactive paraventricular neurons was smaller in depressive and schizophrenic patients than in normal cases. The putative pathophysiologic significance of the reduced expression of paraventricular nitric oxide synthase in depressive patients might be related to the supposed regulatory function of nitric oxide in the release of corticotropin-releasing hormone and arginine-vasopressin and/or oxytocin, which have been reported to be over-expressed in the so-called endogenous psychoses, especially in depression.

Adult↗

Pathological regional cerebral blood flow in opiate-dependent patients during withdrawal: a HMPAO-SPECT study.

The aims of the present study were to investigate regional cerebral blood flow (rCBF) in heroin-dependent patients during withdrawal and to assess the relation between these changes and duration of heroin consumption and withdrawal data. The rCBF was measured using brain SPECT with 99mTc-HMPAO in 16 heroin-dependent patients during heroin withdrawal. Thirteen patients received levomethadone at the time of the SPECT scans. The images were analyzed both visually and quantitatively. A total of 21 hypoperfused brain regions were observed in 11 of the 16 patients. The temporal lobes were the most affected area, hypoperfusions of the right and left temporal lobe were observed in 5 and 5 patients, respectively. Three of the patients had a hypoperfusion of the right frontal lobe, 2 patients showed perfusion defects in the left frontal lobe, right parietal lobe and left parietal lobe. The results of the quantitative assessments of the rCBF were consistent with the results of the qualitative findings. The stepwise regression analysis showed a significant positive correlation (r = 0.54) between the dose of levomethadone at the time of the SPECT scan and the rCBF of the right parietal lobe. Other significant correlations between clinical data and rCBF were not found. The present results suggest brain perfusion abnormalities during heroin withdrawal in heroin-dependent patients, which are not due to the conditions of withdrawal.

Adult↗