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)

1. Ninety psychiatric inpatients with a DSM III diagnosis of schizophrenia, mania, or major depression were studied. 2. Upon admission/transfer to the Clinical Studies Unit, and prior to discharge, measurements of symptom severity (BPRS, Ham-D, Young's Mania Scale) and blood samples were obtained. 3. Erythrocytes from these paired (admission and discharge) blood samples were assayed for methionine adenosyltransferase (MAT) activity and phosphatidylcholine (PC) content. 4. Comparisons were made between the changes in MAT Vmax, or % PC, and changes in symptom severity. 5. For the majority of the patients (79.3% of the schizophrenics; 84.6% of the depressives; and 93.8% of the manics), clinical improvement was associated with a "normalization" of enzyme activity. The association between changes in % PC and clinical response did not achieve significant correlation.
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PMID:Clinical correlations of one-carbon metabolism abnormalities. 340 27

Two independent lines of inquiry have implicated some disturbance of one-carbon cycle metabolism in affective disorders. Folic acid deficiency commonly leads to depression, and S-adenosylmethionine has been reported to have antidepressant properties. Methionine adenosyltransferase has been reported to be underactive in depression and schizophrenia and overactive in mania. This study reports the effects on erythrocyte methionine adenosyltransferase (MAT) kinetics (Vmax) of a 2-week treatment in a population of patients housed on a psychiatric research ward. The drug-free schizophrenic patients and depressives had, upon admission, low Vmax values, and the drug-free manic patients had high Vmax values on admission. After 2 weeks of appropriate treatment, the values for all three patient samples showed significant normalization (i.e., the levels rose in schizophrenics and depressives and fell in manics). We have further shown that pretreatment low levels of erythrocyte membrane phosphatidylcholine in depressives and high levels in manics show statistically significant normalization following 2 weeks of pharmacotherapy. The significance of these results is discussed.
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PMID:Abnormalities of one-carbon metabolism in psychiatric disorders: study of methionine adenosyltransferase kinetics and lipid composition of erythrocyte membranes. 379 Jun 25

This is a review of the present state of knowledge in the area of biological markers that may delineate subpopulations of patients with major psychotic illness. Postmortem studies have revealed that schizophrenia is associated with an excess of dopamine (DA) receptors in the limbic system. A more clinically useful adaptation of this approach has been a study of DA D2 receptors in lymphocytes. Studies of monoamine oxidase, dopamine-beta-hydroxylase, and dimethyltryptamine have not fulfilled their early promise nor have the peptides provided useful information as to possible biological markers. Recent studies of the one-carbon cycle enzymes, methionine adenosyltransferase and serine hydroxymethyltransferase, suggest that underactivity of these, particularly the former, may be a reliable clinical marker for a subgroup of schizophrenics. The computerized axial tomography (CAT) scan abnormalities of schizophrenia establish useful indices of abnormal cerebral anatomy such as cortical atrophy with enlarged ventricles, cortical asymmetries, and atrophy of the cerebellar vermis. Positron emission tomography studies with 18F 2-deoxyglucose (2DG) have shown that many schizophrenics have a higher 2DG uptake in the occipital and temporal rather than the frontal cortex, thus reversing the normal patterns. The dexamethasone suppression test is a valuable biological marker for certain depressions. It may also be useful in identifying subgroups of the schizoaffective disorders, with some schizoaffectives showing an abnormal affective-like response and others not. These and other discriminating biological markers are discussed in this report.
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PMID:Biological markers for the schizophrenic and atypical psychoses. 675 69

Recently developed enzyme tests that are used in (a) identifying high risk populations, (b) diagnosing cancer, (c) following treatment response of cancer patients, and (d) the selection of cancer therapy are summarized. The diagnostic role of methionine adenosyltransferase and CSF monoamine oxidase activity measurements in the diagnosis of schizophrenia are discussed. The role of N-acetyltransferase in the conversion of serotonin to melatonin in the pineal gland and the importance of these changes for the synchronization of the functioning of cells throughout the organism are described. New developments in the determination of immunoreactive trypsin in the early diagnosis of pancreatic diseases are summarized.
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PMID:Present and future trends in selected areas of clinical enzymology. 677 51

We have observed significantly lower kinetic parameters (KM and Vmax) for methionine adenosyltransferase activity in erythrocytes obtained from early onset schizophrenics when compared to samples from normal subjects. These differences are apparently not due to differences in S-adenosylmethionine (SAM) utilization. These results offer an explanation for the conflicting reports of previous investigators and support the concept that undermethylation may characterize some forms of schizophrenia. Methylation is involved in multiple aspects of metabolism and although similar differences in the MAT enzyme in the brain have not been reported, such a deficit could have profound effects on the nervous system. Decreased availability of SAM could decrease catecholamine metabolism or rates of phospholipid methylation.
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PMID:Kinetic evidence for decreased methionine adenosyltransferase activity in erythrocytes from schizophrenics. 717 80

The activity of methionine adenosyltransferase (MAT) was investigated in erythrocytes and postmortem brain specimens (cortex gyrus frontalis, hippocampus and thalamus) of patients with schizophrenia treated with neuroleptics. In comparison with the control group, abnormally low values of MAT Vmax and an increased MAT affinity towards methionine (lower Km values) were found in erythrocytes. In the brain, a regionally selective decrease of MAT Km was found in cortex gyrus frontalis but the Vmax values were however, unchanged. In the regions of cortex gyrus frontalis and hippocampus, but not in thalamus, the values of Vmax and Km were inversely correlated with the duration of schizophrenia. In rats treated for 28 days with the typical neuroleptic haloperidol and the atypical clozapine, a significant increase of MAT activity was found in the corpus striatum. There is the possibility that the changes observed in MAT activity in patients with schizophrenia are attributed to the neuroleptic medication.
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PMID:Erythrocyte and brain methionine adenosyltransferase activities in patients with schizophrenia. 992 98