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Query: UMLS:C0036341 (schizophrenia)
 60,220 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Three sets of young identical twins where at least one had a psychotic episode were assessed in terms of psychiatric and psychological status and integrity of cerebral structure and metabolism. The psychiatric diagnoses for each set were normal/schizophrenia, prodromal/schizophrenia and schizoaffective/schizoaffective. The latter two sets were re-examined two years after the initial assessment. The data are considered from a case study perspective. Reduced cerebral metabolism was found for at least one region on eight of nine scans of patients with a psychotic history. On seven of the nine scans, glucose metabolism in the orbital frontal cortex was reduced. These findings are discussed with respect to previous studies of glucose metabolism in patients with schizophrenia, metabolic similarities found in normal identical twins and the known functional specialization of the orbital frontal cortex.
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PMID:Regional cerebral glucose metabolism in three sets of identical twins with psychotic symptoms. 278 42

The effects of phencyclidine (PCP) on regional cerebral glucose utilization was determined by using quantitative autoradiography with [14C]-2-deoxyglucose. PCP increased brain metabolism in selected areas of cortex, particularly limbic, and in the basal ganglia and thalamus, whereas the drug decreased metabolism in areas related to audition. These results are consistent with the known physiology of central PCP neurons and may help to suggest brain areas involved in PCP-mediated actions. Moreover, based on the behavioral similarities between PCP psychosis and an acute schizophrenic episode, these data may be relevant to the understanding of schizophrenia. The PCP-receptor-acylating agent, metaphit, blocked most of these PCP actions. In addition, metaphit by itself was found to diminish glucose utilization rather uniformly throughout brain. These results indicate an antagonist effect of metaphit on the PCP system and suggest a widespread action of metaphit, putatively at a PCP-related site, possibly in connection with the N-methyl-D-aspartate (NMDA) receptor.
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PMID:PCP-induced alterations in cerebral glucose utilization in rat brain: blockade by metaphit, a PCP-receptor-acylating agent. 285 Jun 26

Schizophrenia is increasingly believed to represent a group of organic disorders which primarily, although not exclusively, affect the central nervous system. Our purpose is to review a representative sample of twentieth-century literature which speaks to the biological substrates of the syndrome. Subjects reviewed include genetic and environmental contributions to the onset of illness, early and recent findings of gross structural anomalies, and apparent histopathological alterations in cerebral cortex, cerebellar vermis, limbic system, and brain stem, as well as problems of cerebral asymmetry. Data from a diverse group of electrophysiological studies reveal several promising correlates of these areas of investigation. Despite the inconsistent nature of the findings to date, several themes have begun to emerge, including patterns of hypofrontal/hyperparietal regional cerebral flow and glucose utilization, left hemispheric dysfunction, and deficits of interhemispheric information processing. The interpretation and significance of these emerging patterns remains unclear and must await more profound insights into the nature of normal and abnormal cerebral function.
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PMID:Biological substrates of schizophrenia. 286 35

Glucose metabolic rate in the basal ganglia, thalamus, and somatosensory cortex was examined in eight patients with schizophrenia before and after receiving neuroleptic medication. Basal ganglia metabolic rates were increased with medication: more on the right than on the left and more in putamen than caudate. The cortical anteroposterior ratio, an index of relative hypofrontality, was not affected by neuroleptics. The brain areas that were found to be altered by neuroleptics were selected for comparison between off-medication schizophrenics and controls. Metabolic rates in the basal ganglia tended to be low in patients with schizophrenia in comparison to 24 age- and sex-matched controls.
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PMID:Positron emission tomography studies of basal ganglia and somatosensory cortex neuroleptic drug effects: differences between normal controls and schizophrenic patients. 288 88

This study examines whether the duration of treatment with antipsychotic drugs influences the regional distribution of cerebral [18F]2-fluoro-2-deoxy-D-glucose utilization as measured by positron emission tomography. Two groups of schizophrenic patients are compared with normal volunteers (n = 10). One group (n = 5) consisted of patients treated for one year, and the second (n = 12) of patients medicated for four to 14 years (mean +/- SD duration, 7.4 +/- 3.4 years). The first group was also examined before patients received their first dose ever of antipsychotic medication. One year of medication was not sufficient to alter the schizophrenic profile of cerebral cortical glucose activity but did elevate activity of the corpus striatum. Medication for 7.4 years also did not alter the schizophrenic pattern of frontal hyperactivity and posterior hypoactivity, although deviations from control values appeared less marked than after one year. On the other hand, in patients medicated for 7.4 years, there was perhaps an even greater increase in the activity of the corpus striatum and of the thalamus. Thus, duration of exposure to antipsychotic medication may affect the pattern of cerebral glucose activity; possibly, even longer exposure may contribute to the hypofrontality noted by others, although this can be confounded with the duration of illness as a factor. In considering the biological significance of the observed profile of cortical glucose activity, we introduce the concept of cerebral metabolic tone. We suggest that a disturbance of this tonus may account for some symptoms of schizophrenia and could be consistent with the hypothesis of abnormal developmental changes in the brains of schizophrenics.
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PMID:Effect of neuroleptics on altered cerebral glucose metabolism in schizophrenia. 289 36

Our previous observation of a disturbed subcortical-to-cortical gradient of activity in schizophrenia was further elucidated by examining glucose metabolism in three subcortical structures: lenticular nucleus, caudate nucleus, and thalamus. Local cerebral glucose metabolism was determined with 18F-fluorodeoxyglucose using positron emission tomography (PET) in a sample of 20 unmedicated schizophrenics and 18 normal volunteers. Repeated evaluations were performed for 12 schizophrenics following treatment with psychotropic medications and for 11 controls. Unmedicated schizophrenics had lower cortical and caudate absolute metabolic rates. Subcortical-to-cortical ratios for the lenticular nucleus and thalamus were increased in schizophrenics compared with controls, reflecting a preservation of activity in these structures relative to decreased cortical metabolism. When patients were grouped by length of medication-free period before the initial study, there was a trend for patients who had been medication free less than 6 months to have higher subcortical ratios. However, there were no consistent effects of medication in the subsample of patients whose PET studies were repeated following treatment. The results demonstrate relative hypermetabolism in structures implicated in dopamine pathways. An understanding of the physiological significance of this finding awaits the combined measurement of metabolic activity and neuroreceptors in schizophrenics.
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PMID:Positron emission tomography and subcortical glucose metabolism in schizophrenia. 289 31

The (F-18) fluorodeoxyglucose (FDG) technique to measure local cerebral metabolic rate for glucose (LCMRglu) is well accepted and widely used by many institutions around the world. A large number of studies has been carried out in normal volunteers and patients with a variety of CNS disorders. Several investigators have noted that no significant age-related changes in cerebral glucose use occur with normal aging. Some important and interesting findings have been revealed following sensory, motor, visual, and auditory stimulations. Functional imaging with FDG in certain neurologic disorders has dramatically improved our understanding of their underlying pathophysiologic phenomena. Some abnormalities detected on the positron emission tomography (PET) images have no corresponding changes on either x-ray computed tomograms (XCT) or magnetic resonance images (MRI). In patients with Alzheimer's disease, primary sensorimotor, visual, and cerebellar metabolic activity appears relatively preserved. In contrast, parietal, temporal, and to some degree, frontal glucose metabolism is significantly diminished even in the early stages of the disease. Patients with Huntington's disease and those at risk of developing this disorder have a typical pattern of diminished CMRglu in the caudate nuclei and putamen. In patients with stroke, PET images with FDG have demonstrated abnormal findings earlier than either XCT or MRI and with a wider topographic distribution. FDG scans have revealed interictal zones of decreased LCMRglu in approximately 70% of patients with partial epilepsy. The location of the area of hypometabolism corresponds to the site of the epileptic focus as determined by electroencephalography and microscopic examination of the resected tissue. Ictal scans during partial seizures demonstrate areas of hypermetabolism corresponding to the sites of seizure onset and spread. Several investigators have reported relative hypofrontal CMRglu in patients with schizophrenia. In our center, FDG scans from patients with schizophrenia were successfully differentiated from those obtained in normal controls. Finally, our preliminary data (using PET, XCT, and MRI) in patients with CNS disorders indicate that MRI provides excellent delineation of the structural abnormalities. It may prove to be superior to XCT in the evaluation of certain diseases such as cerebral ischemia and infarcts, head injury, tumors, and white matter lesions. Metabolic imaging with FDG provides functional information not obtainable with either MRI or NMR spectroscopy. Therefore, PET studies will play a complementary role to the anatomic imaging in the management of patients with CNS disorders.
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PMID:Positron emission tomography imaging of regional cerebral glucose metabolism. 293 38

Recent advances in brain imaging have allowed a regional examination of brain function using multiple-probe inert gas studies of cerebral blood flow, positron or single photon tomography. Inert gas blood flow methods using inhalation or injection of 133xenon have been used with multiple-probe systems to measure blood flow in 1 to 2 cm regions of lateral cortex. The sensitivity of these systems to neurophysiological stimuli and neurological diseases have been demonstrated in numerous studies of the normal resting state, memory and learning, motor activity and sensory input, dementia, and aphasia, to name some. Positron tomography utilizes cyclotron-produced, short-lived positron-emitting isotopes to label biologically active radiopharmaceuticals. Using positron tomographs capable of quantitative three-dimensional imaging and appropriate tracer-kinetic models, regional metabolic function, including glucose, oxygen, amino acid metabolism, and receptor-binding can be regionally studied throughout the brain. Clinical studies have been performed in dementia, schizophrenia, affective disorders, resting states, and sensory stimulation. Positron tomography offers potentially the greatest variety of studies and highest temporal and spatial resolution of any of the presently available functional brain-imaging modalities. Its principal drawback is the very high cost. Single photon tomography uses gamma-emitting isotopes such as 123iodine and 133xenon to image regional cerebral blood flow and recently receptor function. Although at present it does not have the variety of studies or the technical capabilities of positron tomography, it does provide three-dimensional studies with 1 to 2 cm resolutions throughout the brain at a considerably lower cost than positron tomography. In the future, magnetic resonance studies of blood flow or phosphorus metabolism may add a fourth modality.
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PMID:Functional brain imaging. 298 79

Cerebral imaging of depressive syndromes has been studied since the early eighties in search of organic or functional anomalies in the central nervous system. There are fewer studies than with schizophrenia. Computed tomography, scintiscan, positron emission tomography (PET) are being used in various depressive states. For methodological reasons, results with PET are only preliminary. EEG mapping, a new technique, has, above all, measured the abnormalities of organic brain syndromes, especially dementia, which has to be ruled out in the diagnosis of depression. CT scan has not substantiated any cerebral defects in depressed patients in the comparative case-control studies, except for some clinical types (aged population or forms associated with delusional or hallucinatory syndromes) where images of cortico-subcortical atrophy have been observed. Scintiscan and PET scan have shown a decreased cerebral blood flow, with a Xenon 133 test, and PET scan a decreased consumption of glucose on condition that depressed subjects are cognitively resting, in comparison to matched controls. In EEG mapping an index of spacetiation of the basal quantitative EEG activity typifies cases of evolution towards dementia, which has to be ruled out in the diagnosis of involutional depression.
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PMID:[Cerebral imaging and depressive disorder]. 332

Positron emission tomography (PET) with 11C-2-deoxyglucose (11DG) was used to compare regional brain metabolism in four patients with chronic schizophrenia who had no history of psychotropic medication and in 12 normal controls. Patients had a second PET scan after an injection of thiothixene to evaluate the effects of acute neuroleptics on glucose metabolism. The patients showed higher glucose metabolic values than the normals and did not show the metabolic hypofrontality reported in chronic medicated patients with schizophrenia. Administration of the neuroleptic did not have a significant effect in the metabolic pattern of the patients. These results give support to the hypothesis that prolonged medication may contribute to the metabolic hypofrontal pattern seen in patients with schizophrenia.
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PMID:Brain metabolism in patients with schizophrenia before and after acute neuroleptic administration. 349 Nov 82


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