Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0036341 (schizophrenia)
 60,220 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Sixteen unmedicated (14 never-medicated, 2 with washout periods of 1-2 weeks) schizophrenic patients displaying positive symptoms (e.g., formal thought disorder, hallucinations, delusions) without negative symptoms (e.g., flattening of affect, loss of energy, anhedonia--type I patients), 15 unmedicated (with washout periods from 1 week to 2 years) patients with marked negative symptomatology [type II patients; criterion score below 15/above 35 on the Munich version of the Scale of Assessment of Negative Symptoms (SANS), respectively], and 31 matched normal controls were investigated using regional cerebral blood flow [rCBF; dynamic single-photon emission computerized tomography (SPECT) with Xenon-133 as tracer] and magnetic resonance imaging (MRI; spin-echo technique, T1 weighted, midsagittal cuts). rCBF measurements were performed during both resting conditions and simple motor activation. Separately, on the same day, we performed a planimetric evaluation of the callosal-brain ratio in all subjects using MRI. In accordance with previous results on a smaller sample, we found signs of diffuse bilateral rCBF hyperactivation in type I patients, as compared with signs of nonreactivity in type II schizophrenics. Both activation patterns were different from a strictly contralateral sensorimotor rCBF activation seen in normal persons (only 8 studied with SPECT). The planimetry of relative callosal area did not reveal differences compared to normal persons, when type I/II patients were taken together. However, the threefold increased variance as compared with that found in normal persons suggested biological heterogeneity in patients. We found an increase of relative callosal size in type I as compared with type II patients. In the light of some recent findings linking lack of laterality of several brain functions to increased callosal size, we propose lack of laterality/diffuse hyperactivation and increased callosal size to be connected with positive symptomatology/good prognosis schizophrenia, and vice versa.
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PMID:Brain dysfunction during motor activation and corpus callosum alterations in schizophrenia measured by cerebral blood flow and magnetic resonance imaging. 190 62

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

Neuroimaging has advanced the study of brain structure and function in schizophrenia. Magnetic resonance imaging provides measures of whole brain and regional anatomy and cerebrospinal fluid volume. Functional methods have included the Xenon-133 technique for measuring cerebral blood flow (CBF); positron emission tomography for assessing metabolism, CBF, and neuroreceptor functioning; and single photon emission computed tomography for studying CBF and neuroreceptors. Despite heterogeneity of patient samples, and studies which differed in the methodologies applied, there is converging evidence implicating three brain systems: frontal, temporolimbic, and basal ganglia. Current emphasis is aimed at probing specific regions across imaging modalities. Now these findings and research paradigms in neuroimaging must be integrated with phenomenological, neurobehavioral, and neuropathological investigations. The application of this technology is already helping to elucidate the neurobiology of schizophrenia, and further important advances can be anticipated.
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PMID:Neuroimaging in schizophrenia research. 832 37

Single-photon emission computed tomography (SPECT) of the brain has been used to define functional abnormalities in two groups of childhood behavior disorders: (1) a "primary" category in which there is exclusive or predominant presentation with cognitive and/or behavioral dysfunction and (2) encephalopathies, often defined etiologically at the biochemical or molecular level, in which clinical expression includes, but is not confined to, neural dysfunction. Radiopharmaceuticals available for such studies are manifold, but those used to date have been predominantly perfusion agents, eg, Xenon-133 (133Xe) and technetium-99m (99mTc) hexamethylpropylene amine oxime, and studies with [99mTc]bicisate are eagerly awaited. Xenon-133 studies require that the patient be in the field of view of the detector while the tracer is administered. This renders it difficult for a subject to perform cognitive and other exercises while being imaged, because the environment is quite foreign. On the other hand, the 99mTc-labeled perfusion agents permit a scintigraphic "snapshot" of regional cerebral blood flow during a behavioral event without having to have the patient under the imaging instrument. Thus, one can separate the administration of the radiotracer, which can be done under more controlled and physiological conditions, from the actual imaging. In addition, greater spatial resolution is achieved with the technetium-based agents. Currently, multidetector or dedicated annular crystal-type cameras are the preferred brain SPECT devices, and they are essential to applications such as cortical "activation mapping" or tomographic detection of receptor systems. Close attention to technical detail and standardization of the child's behavioral environment during the investigation are critical to a successful study. The relative advantages and disadvantages of qualitative versus semiquantitative analysis of imaging date are reviewed. Among primary behavioral disorders, 133Xe SPECT studies in attention deficit disorder-hyperactivity (ADHD) have suggested a pattern of hypoperfusion of striatal and periventricular structures with sensorimotor cortical hyperperfusion. This pattern is consistent with some neurophysiological models of the disorder. In cerebral palsy, perfusional abnormalities have paralleled clinical deficits and may offer information to help predict outcome. The important field of childhood affective disorders (schizophrenia, juvenile autism, depression, etc) remains largely unstudied with SPECT. Finally, representative examples of the use of SPECT to study perfusion in encephalopathies with behavioral expression (phenylketonuria, MELAS (mitochondrial encephalomyopathy with lactic acidosis and stroke-like episodes) syndrome, Wilson's disease, etc) are given.
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PMID:Brain single-photon emission computed tomography for behavior disorders in children. 837 98