UMLS:C0036341 - FACTA Search

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

Measurement of the regional cerebral blood flow (rCBF) is an important parameter in the evaluation of cerebral function. With positron emission tomography (PET) rCBF has predominantly been quantified using the short-lived radiotracer oxygen-15 labelled water (H 2 15 O) and an adaptation of the Kety one-tissue compartment autoradiographic model. The values attained in putative grey matter, however, are systematically underestimated because of the limited scanner resolution. For this reason we applied a dynamic kinetic two-tissue compartment model including a fast and a slow flow component each with a perfusable tissue fraction. In the fast component rCBF was 2-2.5 times greater than grey matter values using traditional autoradiography in both human and monkey. Visual stimulation in human gave a corrected rCBF increase of approximately 40%. Visual stimulation was also used to indirectly validate carbon-10 labelled carbondioxide ( 10 CO 2 ), a new very short-lived rCBF PET tracer with a half-life of only 19.3 seconds. This allowed an increase in the number of independent PET scans per subject from 12-14 using H 2 15 O to 64 using 10 CO 2 . The experiment demonstrated a maximal activation response in the visual cortex at a 10-15 Hz stimulation frequency. The use of the rCBF PET mapping technique is illustrated by studies of the organization of language and the oculomotor system. With respect to the former, we found confirmation of neuropsychological evidence of the involvement of the left supramarginal/angular gyrus in reading in Japanese of a phonologically based script system, Kana, and of the left posterior inferior temporal gyrus in reading of a morphogram based script system, Kanji. Concerning the organization of the oculomotor system we found overlapping areas in fronto-parietal cortex involved in maintaining visual fixation, and performing visually guided and imagined eye movements. These data show that overt eye movements are not a prerequisite of the activation of classical cortical oculomotor regions and underscore the involvement of these areas in other behaviours such as visual attention and saccade inhibition. During eye movements in the dark an increased activation response in the parieto-occipital cortex can be found. This can be interpreted as effects of the gaze-sensitive neurons that are used to objectively localize objects relative to the body, and efferent copies of motor commands, used to predict the visual consequences of eye movements to maintain visual continuity. Defect efferent copies are in some neurobiological models of schizophrenia thought to contribute to passivity phenomena. The clinical perspective of brain mapping techniques is to preoperatively locate eloquent areas, e.g. motor function, language, and memory, allowing the achievement of optimal neurosurgical resection with the preservation of neurological function.
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PMID:Human brain mapping under increasing cognitive complexity using regional cerebral blood flow measurements and positron emission tomography. 1820 79

Accumulating evidence points to relationships between increased production of reactive oxygen or decreased antioxidant protection in schizophrenic patients. Chlorpromazine (CPZ), which remains a benchmark treatment for people with schizophrenia, has been described as a pro-oxidant compound. Because the antioxidant compound melatonin exerts protective effects against CPZ-induced liver disease in rats, in this investigation, our main objective was to study the effect of CPZ as a co-catalyst of peroxidase-mediated oxidation of melatonin. We found that melatonin was an excellent reductor agent of preformed CPZ cation radical (CPZ(*+)). The addition of CPZ during the horseradish peroxidase (HRP)-catalyzed oxidation of melatonin provoked a significant increase in the rate of oxidation and production of N(1)-acetyl-N(2)-formyl-5-methoxykynuramine (AFMK). Similar results were obtained using myeloperoxidase. The effect of CPZ on melatonin oxidation was rather higher at alkaline pH. At pH 9.0, the efficiency of oxidation of melatonin was 15 times higher and the production of AFMK was 30 times higher as compared with the assays in the absence of CPZ. We suggest that CPZ is able to exacerbate the rate of oxidation of melatonin by an electron transfer mechanism where CPZ(*+), generated during the peroxidase-catalyzed oxidation, is able to efficiently oxidize melatonin.
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PMID:The co-catalytic effect of chlorpromazine on peroxidase-mediated oxidation of melatonin: enhanced production of N1-acetyl-N2-formyl-5-methoxykynuramine. 1828 61

Many psychiatric patient groups smoke heavily, but little is known regarding the effects of this habit on functional brain imaging results. The present report assesses the effect of chronic smoking on the blood oxygen level-dependent (BOLD) response to a simple visual activation (VA) task and a breath hold (BH) task in patients with schizophrenia. Eight healthy controls and twelve patients with schizophrenia were studied. Half of each group had never smoked and the other half of each group had smoked for more than 10 pack years. Responses to the VA task were assessed in the visual cortex and responses to the BH task were assessed in gray matter generally. There were four fMRI-dependent measures: (1) median percent signal change; (2) activation volume (in voxels); (3) time-to-peak of the impulse response function (IRF); and (4) time-to-trough of the IRF. All measures were tested as dependent variables in an ANCOVA with diagnosis and smoking status as crossed factors and age as a covariate. Heavy smokers had 22% larger percent signal change for the VA task and 50% larger percent signal change for the BH task. Patients had a 40% larger percent signal change for the breath hold task. Other statistically significant effects of smoking history on activation volume and the timing of the brain responses were noted. If replicated, the results may have important implications for fMRI studies comparing groups with markedly different smoking habits, such as studies comparing patients with schizophrenia, 60-90% of whom smoke, and healthy controls, who smoke with a much lower frequency.
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PMID:Chronic smoking and the BOLD response to a visual activation task and a breath hold task in patients with schizophrenia and healthy controls. 1828 81

It is well known that chronic, excessive consumption of alcohol can cause brain damage/structural changes in the regions important for neurocognitive function. Some of the damages are permanent, while others are reversible. Molecular mechanisms underlying alcohol-induced and/or -related brain damage are largely unknown, although it is generally believed that three factors (ethanol, nutritious and hepatic factors) play important roles. Recently, we have been employing a high-throughput proteomics technology to investigate several alcohol-sensitive brain regions from uncomplicated and hepatic cirrhosis-complicated alcoholics to understand the mechanisms of alcohol effects on the CNS at the level of protein expression. The changes of protein expression profiles in the hippocampus of alcoholic subjects were firstly demonstrated using 2D gel electrophoresis-based proteomics. Protein expression profiles identified in the hippocampus of alcoholic subjects were significantly different from those previously identified by our group in other brain regions of the same alcoholic cases, possibly indicating that these different brain regions react differently to chronic alcohol ingestion at the level of protein expression. Identified changes of protein expression associated with astrocyte and oxidative stress may indicate the possibility that increased levels of CNS ammonia and reactive oxygen species induced by alcoholic mild hepatic damage/dysfunction could cause selective damage in astrocytes of the hippocampus. Although our data did not demonstrate any evidence of direct alcohol effects to induce the alteration of protein expression in association with brain damage, high-throughput neuroproteomics approaches have proved to have the potential to dissect the mechanisms of complex brain disorders. Proteomics studies on human hippocampus, an important region for neurocognitive function and psychiatric illnesses (e.g., Alzheimer's disease, alcoholism and schizophrenia) are still sparse, and further investigation is warranted to understand the underlying mechanisms.
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PMID:Alcoholism: protein expression profiles in a human hippocampal model. 1846 60

Schisandra chinensis (Turcz.) Bail. is often referred to as an example of a medicinal plant with use in modern Chinese medicine. However, Schisandra chinensis first gained recognition as an adaptogen in the official medicine of the USSR in the early 1960s, principally as a result of the large number of pharmacological and clinical studies carried out by Russian scientists in the preceding two decades. Schizandra has now secured an established position within the medicine of Russia/USSR as evidenced by the inclusion of the drug in recent editions of the National Pharmacopoeia of the USSR and in the State Register of Drugs. Pharmacological studies on animals have shown that Schizandra increases physical working capacity and affords a stress-protective effect against a broad spectrum of harmful factors including heat shock, skin burn, cooling, frostbite, immobilisation, swimming under load in an atmosphere with decreased air pressure, aseptic inflammation, irradiation, and heavy metal intoxication. The phytoadaptogen exerts an effect on the central nervous, sympathetic, endocrine, immune, respiratory, cardiovascular, gastrointestinal systems, on the development of experimental atherosclerosis, on blood sugar and acid-base balance, and on uterus myotonic activity. Studies on isolated organs, tissues, cells and enzymes have revealed that Schizandra preparations exhibit strong antioxidant activities and affect smooth muscles, arachidonic acid release, biosynthesis of leukotriene B(4) in leukocytes, platelet activating factor activity, carbohydrate-phosphorus metabolism, the formation of heat shock protein and polyamines, tissue respiration and oxygen consumption, and the tolerance of an organism to oxygen intoxication. In healthy subjects, Schizandra increases endurance and accuracy of movement, mental performance and working capacity, and generates alterations in the basal levels of nitric oxide and cortisol in blood and saliva with subsequent effects on the blood cells, vessels and CNS. Numerous clinical trials have demonstrated the efficiency of Schizandra in asthenia, neuralgic and psychiatric (neurosis, psychogenic depression, astheno-depressive states, schizophrenia and alcoholism) disorders, in impaired visual function, hypotension and cardiotonic disorders, in epidemic waves of influenza, in chronic sinusitis, otitis, neuritis and otosclerosis, in pneumonia, radioprotection of the fetoplacental system of pregnant women, allergic dermatitis, acute gastrointestinal diseases, gastric hyper- and hypo-secretion, chronic gastritis, stomach and duodenal ulcers, wound healing and trophic ulcers. This review describes the considerable diversity of pharmacological effects of Schisandra chinensis reported in numerous studies carried out in the former USSR and which have been confirmed over more than 40 years of use of the plant as an official medicinal remedy. Such knowledge can be applied in the expansion of the use of Schizandra in the pharmacotherapy of European and other countries as well as for the further discovery of new drugs based on the lignans that constitute the main secondary metabolites of this plant.
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PMID:Pharmacology of Schisandra chinensis Bail.: an overview of Russian research and uses in medicine. 1851 24

Synaptophysin, a synaptic vesicle protein and a marker for synaptic density has been found to be reduced in postmortem prefrontal cortex of schizophrenia patients, consistent with evidence for synaptic deficits in schizophrenia. The contribution of both genetic and environmental factors to the etiology of schizophrenia is well established, and obstetric complications have been suggested as a non-genetic risk factor of schizophrenia. As there is only scarce evidence for a genetic linkage between synaptophysin's chromosomal locus (Xp11.22) and schizophrenia, we hypothesized that early neonatal exposure of rat pups to oxygen restriction would result in reduced frontal cortex synaptophysin protein levels at adulthood. We studied the effects of anoxia or hypoxia on 7-day-old rats frontal cortex synaptophysin protein levels assessed by Western blotting 4 and 7 weeks following the exposure. In hypoxia- or anoxia-exposed rats, synaptophysin protein levels were elevated both 4 and 7 weeks after the exposure. Two-way ANOVA followed by post hoc LSD analysis showed that the effect was predominantly at 4 weeks after exposure and that only anoxia-exposed rats differed significantly from control rats (p = 0.019). These results are in contrast to postmortem findings in schizophrenia and suggest that reduced synaptophysin protein levels in schizophrenia patients' postmortem brain do not result from perinatal oxygen deprivation.
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PMID:Perinatal oxygen restriction does not result in reduced rat frontal cortex synaptophysin protein levels at adulthood as opposed to postmortem findings in schizophrenia. 1862 94

Identifying intermediate phenotypes of genetically complex psychiatric illnesses such as schizophrenia is important. First-degree relatives of persons with schizophrenia have increased genetic risk for the disorder and tend to show deficits on working memory (WM) tasks. An open question is the relationship between such behavioral endophenotypes and the corresponding brain activation patterns revealed during functional imaging. We measured task performance during a Sternberg WM task and used functional magnetic resonance imaging (fMRI) to assess whether 23 non-affected first-degree relatives showed altered performance and functional activation compared to 43 matched healthy controls. We predicted that a significant proportion of unaffected first-degree relatives would show either aberrant task performance and/or abnormal related fMRI blood oxygen level dependent (BOLD) patterns. While task performance in the relatives was not different than that of controls they were significantly slower in responding to probes., Schizophrenia relatives displayed reduced activation, most markedly in bilateral dorsolateral/ventrolateral (DLPFC/VLPFC) prefrontal and posterior parietal cortex when encoding stimuli and in bilateral DLPFC and parietal areas during response selection. Additionally, fMRI differences in both conditions were modulated by load, with a parametric increase in between-group differences with load in several key regions during encoding and an opposite effect during response selection.
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PMID:An fMRI study of working memory in first-degree unaffected relatives of schizophrenia patients. 1867 69

Deregulated lipid metabolism may be of particular importance for CNS injuries and disorders, as this organ has the highest lipid concentration next to adipose tissue. Atherosclerosis (a risk factor for ischemic stroke) results from accumulation of LDL-derived lipids in the arterial wall. Pro-inflammatory cytokines (TNF-alpha and IL-1), secretory phospholipase A2 IIA and lipoprotein-PLA2 are implicated in vascular inflammation. These inflammatory responses promote atherosclerotic plaques, formation and release of the blood clot that can induce ischemic stroke. TNF-alpha and IL-1 alter lipid metabolism and stimulate production of eicosanoids, ceramide, and reactive oxygen species that potentiate CNS injuries and certain neurological disorders. Cholesterol is an important regulator of lipid organization and the precursor for neurosteroid biosynthesis. Low levels of neurosteroids were related to poor outcome in many brain pathologies. Apolipoprotein E is the principal cholesterol carrier protein in the brain, and the gene encoding the variant Apolipoprotein E4 is a significant risk factor for Alzheimer's disease. Parkinson's disease is to some degree caused by lipid peroxidation due to phospholipases activation. Niemann-Pick diseases A and B are due to acidic sphingomyelinase deficiency, resulting in sphingomyelin accumulation, while Niemann-Pick disease C is due to mutations in either the NPC1 or NPC2 genes, resulting in defective cholesterol transport and cholesterol accumulation. Multiple sclerosis is an autoimmune inflammatory demyelinating condition of the CNS. Inhibiting phospholipase A2 attenuated the onset and progression of experimental autoimmune encephalomyelitis. The endocannabinoid system is hypoactive in Huntington's disease. Ethyl-eicosapetaenoate showed promise in clinical trials. Amyotrophic lateral sclerosis causes loss of motorneurons. Cyclooxygenase-2 inhibition reduced spinal neurodegeneration in amyotrophic lateral sclerosis transgenic mice. Eicosapentaenoic acid supplementation provided improvement in schizophrenia patients, while the combination of (eicosapentaenoic acid + docosahexaenoic acid) provided benefit in bipolar disorders. The ketogenic diet where >90% of calories are derived from fat is an effective treatment for epilepsy. Understanding cytokine-induced changes in lipid metabolism will promote novel concepts and steer towards bench-to-bedside transition for therapies.
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PMID:Altered lipid metabolism in brain injury and disorders. 1875 14

Gene expression changes in neuropsychiatric and neurodegenerative disorders, and gene responses to therapeutic drugs, provide new ways to identify central nervous system (CNS) targets for drug discovery. This review summarizes gene and pathway targets replicated in expression profiling of human postmortem brain, animal models, and cell culture studies. Analysis of isolated human neurons implicates targets for Alzheimer's disease and the cognitive decline associated with normal aging and mild cognitive impairment. In addition to tau, amyloid-beta precursor protein, and amyloid-beta peptides (Abeta), these targets include all three high-affinity neurotrophin receptors and the fibroblast growth factor (FGF) system, synapse markers, glutamate receptors (GluRs) and transporters, and dopamine (DA) receptors, particularly the D2 subtype. Gene-based candidates for Parkinson's disease (PD) include the ubiquitin-proteosome system, scavengers of reactive oxygen species, brain-derived neurotrophic factor (BDNF), its receptor, TrkB, and downstream target early growth response 1, Nurr-1, and signaling through protein kinase C and RAS pathways. Increasing variability and decreases in brain mRNA production from middle age to old age suggest that cognitive impairments during normal aging may be addressed by drugs that restore antioxidant, DNA repair, and synaptic functions including those of DA to levels of younger adults. Studies in schizophrenia identify robust decreases in genes for GABA function, including glutamic acid decarboxylase, HINT1, glutamate transport and GluRs, BDNF and TrkB, numerous 14-3-3 protein family members, and decreases in genes for CNS synaptic and metabolic functions, particularly glycolysis and ATP generation. Many of these metabolic genes are increased by insulin and muscarinic agonism, both of which are therapeutic in psychosis. Differential genomic signals are relatively sparse in bipolar disorder, but include deficiencies in the expression of 14-3-3 protein members, implicating these chaperone proteins and the neurotransmitter pathways they support as possible drug targets. Brains from persons with major depressive disorder reveal decreased expression for genes in glutamate transport and metabolism, neurotrophic signaling (eg, FGF, BDNF and VGF), and MAP kinase pathways. Increases in these pathways in the brains of animals exposed to electroconvulsive shock and antidepressant treatments identify neurotrophic and angiogenic growth factors and second messenger stimulation as therapeutic approaches for the treatment of depression.
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PMID:Target identification for CNS diseases by transcriptional profiling. 1892 5

The thalamus plays a central and dynamic role in information transmission and processing in the brain. Multiple studies reveal increasing association between schizophrenia and dysfunction of the thalamus, in particular the medial dorsal nucleus (MDN), and its projection targets. The medial dorsal thalamic connections to the prefrontal cortex are of particular interest, and explicit in vivo evidence of this connection in healthy humans is sparse. Additionally, recent neuroimaging evidence has demonstrated disconnection among a variety of cortical regions in schizophrenia, though the MDN thalamic prefrontal cortex network has not been extensively probed in schizophrenia. To this end, we have examined thalamo-anterior cingulate cortex connectivity using detection of low-frequency blood oxygen level dependence fluctuations (LFBF) during a resting-state paradigm. Eleven schizophrenic patients and 12 healthy control participants were enrolled in a study of brain thalamocortical connectivity. Resting-state data were collected, and seed-based connectivity analysis was performed to identify the thalamocortical network. First, we have shown there is MDN thalamocortical connectivity in healthy controls, thus demonstrating that LFBF analysis is a manner to probe the thalamocortical network. Additionally, we have found there is statistically significantly reduced thalamocortical connectivity in schizophrenics compared with matched healthy controls. We did not observe any significant difference in motor networks between groups. We have shown that the thalamocortical network is observable using resting-state connectivity in healthy controls and that this network is altered in schizophrenia. These data support a disruption model of the thalamocortical network and are consistent with a disconnection hypothesis of schizophrenia.
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PMID:Low-frequency BOLD fluctuations demonstrate altered thalamocortical connectivity in schizophrenia. 1899 Jul 9

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