| 1 | BMB Rep 2010 Sep 43: 593-8 |
|---|---|
| PMID | 20846490 |
| Title | Alterations in dopamine and glutamate neurotransmission in tetrahydrobiopterin deficient spr-/- mice: relevance to schizophrenia. |
| Abstract | Tetrahydrobiopterin (BH4) is a pivotal cofactor for enzymes responsible for the synthesis and release of monoamine neurotransmitters including dopamine (DA) and serotonin (5-HT) as well as the release of glutamate (Glu). Deficiencies in BH4 levels and reduced activities of BH(4)-associated enzymes have been recently reported in patients with schizophrenia. Accordingly, it is possible that abnormalities in the biochemical cascades regulated by BH(4) may alter DA, 5-HT and Glu neurotransmission, and consequently contribute to the pathophysiology of different neuropsychiatric diseases including schizophrenia. The development of a novel strain of mutant mice that is deficient in BH(4) by knocking out the expression of a functional sepiapterin reductase gene (SPR -/-) has added new insights into the potential role of BH(4) in the pathophysiology and improved treatment of schizophrenia. |
| SCZ Keywords | schizophrenia, schizophrenic |
| 2 | Clin Psychopharmacol Neurosci 2011 Dec 9: 117-21 |
| PMID | 23430042 |
| Title | The Diagnostic Stability of DSM-IV Diagnoses: An Examination of Major Depressive Disorder, Bipolar I Disorder, and Schizophrenia in Korean Patients. |
| Abstract | We examined the stability of diagnoses defined by the Diagnostic and Statistical Manual of Mental Disorders-Fourth Edition (DSM-IV) (major depressive disorder [MDD], bipolar I disorder [BID], and schizophrenia [SPR]) by means of retrospective reviews of medical records. Data from patients who met the DSM-IV criteria for the aforementioned disorders according to two psychiatrists and who were followed for at least 2 years were included in this study. We reviewed the medical records and compared the diagnosis given at the index admission with assessments made every 6 months for 2 years after discharge to determine diagnostic stability. A total of 138 patients with MDD, 56 patients with BID, and 107 patients with SPR who were followed for 2 years were included in the final analyses. The data showed that 84.8% of the sample retained their initial diagnosis of MDD during the first year; this figure decreased to 79.0% during the second year. During the first year, 93.5% retained their initial diagnosis of BID, and this figure decreased to 89.3% during the second year; 86.8% and 86.9% retained their diagnosis of SPR during the first and second years, respectively. This study showed the instability of three major DSM-IV diagnoses among Korean patients. Additionally, the results demonstrated that accurate diagnosis using the current diagnostic system requires longitudinal observation. |
| SCZ Keywords | schizophrenia, schizophrenic |
| 3 | Psychophysiology 2011 Oct 48: 1323-32 |
| PMID | 21496056 |
| Title | Nonlinear relationship between electrodermal activity and heart rate variability in patients with acute schizophrenia. |
| Abstract | We investigated to what degree tonic skin conductance levels (SCL) and cardiac autonomic dysfunction are interrelated in schizophrenia. Heart rate variability (HRV) and SCL were simultaneously assessed in 18 unmedicated patients and 18 controls matched for age, sex, weight, and smoking habits. For comparison to prior studies, phasic sympathetic skin responses (SPR) were also recorded. Compared to controls, patients had prolonged SPR latency and reduced SPR amplitude with a right-greater-than-left asymmetry, which was inversely correlated with positive symptoms. An autonomic imbalance was reflected in linear and nonlinear measures of HRV and increased SCL. Patients showed a stronger nonlinear association between SCL and heart rate than controls. HRV and SCL findings were strongly affected by group differences in breathing rate. Stronger HRV-SCL coupling in patients may suggest augmented sympathetic modulation in schizophrenia. |
| SCZ Keywords | schizophrenia, schizophrenic |
| 4 | J. Nerv. Ment. Dis. 2011 Feb 199: 106-10 |
| PMID | 21278539 |
| Title | Coping strategies and their relationship to psychopathologies in people at ultra high-risk for psychosis and with schizophrenia. |
| Abstract | This study's aim was to investigate coping strategies and their relationship to symptoms in people at ultra high risk (UHR) for psychosis compared with recent-onset schizophrenia (SPR) and healthy controls. Thirty-three UHR participants, 22 SPR patients, and 33 healthy controls completed the Ways of Coping Questionnaire and other clinical measures. People at UHR for psychosis showed significantly more reliance on tension-reduction and less reliance on problem-focused coping than healthy controls. The SPR group showed more reliance on tension-reduction coping than healthy controls at a trend level. Maladaptive coping patterns were associated with higher levels of negative symptoms, depression, and anxiety in both the UHR and SPR groups. These findings suggest that maladaptive coping strategies might have already emerged in the (putative) prodromal stage and could influence symptom severities. |
| SCZ Keywords | schizophrenia, schizophrenic |
| 5 | Exp. Mol. Med. 2012 Feb 44: 121-9 |
| PMID | 22089088 |
| Title | Genetic association of the EGR2 gene with bipolar disorder in Korea. |
| Abstract | The early growth response gene 2 (EGR2) is located at chromosome 10q21, one of the susceptibility loci in bipolar disorder (BD). EGR2 is involved in cognitive function, myelination, and signal transduction related to neuregulin-ErbB receptor, Bcl-2 family proteins, and brain-derived neurotrophic factor. This study investigated the genetic association of the EGR2 gene with BD and schizophrenia (SPR) in Korea. In 946 subjects (350 healthy controls, 352 patients with BD, and 244 with SPR), nine single nucleotide polymorphisms (SNPs) in the EGR2 gene region were genotyped. Five SNPs showed nominally significant allelic associations with BD (rs2295814, rs61865882, rs10995315, rs2297488, and rs2297489), and the positive associations of all except rs2297488 remained significant after multiple testing correction. Linkage disequilibrium structure analysis revealed two haplotype blocks. Among the common identified haplotypes (frequency > 5%), 'T-G-A-C-T (block 1)' and 'A-A-G-C (block 2)' haplotypes were over-represented, while 'C-G-G-T-T (block 1)' haplotype was under-represented in BD. In contrast, no significant associations were found with SPR. Although an extended analysis with a larger sample size or independent replication is required, these findings suggest a genetic association of EGR2 with BD. Combined with a plausible biological function of EGR2, the EGR2 gene is a possible susceptibility gene in BD. |
| SCZ Keywords | schizophrenia, schizophrenic |
| 6 | Glycobiology 2015 Oct 25: 1112-24 |
| PMID | 26163659 |
| Title | Protective effects of polysialic acid on proteolytic cleavage of FGF2 and proBDNF/BDNF. |
| Abstract | Polysialic acid (polySia) is a linear polymer of sialic acid that modifies neural cell adhesion molecule (NCAM) in the vertebrate brain. PolySia is a large and exclusive molecule that functions as a negative regulator of cell-cell interactions. Recently, we demonstrated that polySia can specifically bind fibroblast growth factor 2 (FGF2) and BDNF; however, the protective effects of polySia on the proteolytic cleavage of these proteins remain unknown, although heparin/heparan sulfate has been shown to impair the cleavage of FGF2 by trypsin. Here, we analyzed the protective effects of polySia on the proteolytic cleavage of FGF2 and proBDNF/BDNF. We found that polySia protected intact FGF2 from tryptic activity via the specific binding of extended polySia chains on NCAM to FGF2. Oligo/polySia also functioned to impair the processing of proBDNF by plasmin via binding of oligo/polySia chains on NCAM. In addition, the polySia structure synthesized by mutated polysialyltransferase, ST8SIA2/STX(SNP7), which was previously identified from a schizophrenia patient, was impaired for these functions compared with polySia produced by normal ST8SIA2. Taken together, these data suggest that the protective effects of polySia toward FGF2 and proBDNF may be involved in the regulation of the concentrations of these neurologically active molecules. |
| SCZ Keywords | schizophrenia, schizophrenic |
| 7 | Neuropsychiatr Dis Treat 2015 -1 11: 2793-9 |
| PMID | 26604763 |
| Title | Association study of sepiapterin reductase gene promoter polymorphisms with schizophrenia in a Han Chinese population. |
| Abstract | Sepiapterin reductase participates in the biosynthesis of tetrahydrobiopterin, which plays very important roles in the pathogenesis of schizophrenia via dysregulation of neurotransmitter systems. Here, two single nucleotide polymorphisms (rs1876487 and rs2421095) in the promoter region of SPR were genotyped in 941 schizophrenic patients and 944 controls in a Han Chinese population using the SNaPshot technique. No significant differences were found in the distribution of alleles or genotypes of the two single nucleotide polymorphisms (SNPs) between schizophrenic patients and controls (all P>0.05). Likewise, no haplotype was found to be associated with schizophrenia. However, sex-stratified analysis revealed that the frequencies of the A allele of rs1876487 and the A-A (rs2421095-rs1876487) haplotype were all significantly different between schizophrenia and controls in females (P=0.040 and P=0.033, respectively), but not in males. Additionally, luciferase reporter gene assays revealed that the A-A haplotype had significantly higher SPR transcriptional activity compared with the A-C haplotype in SH-SY5Y cells. Our data indicate that the two SNPs do not influence the risk of schizophrenia when using the total sample, but the A allele of rs1876487 and the A-A haplotype may contribute to protective roles for schizophrenia in females. |
| SCZ Keywords | schizophrenia, schizophrenic |
| 8 | Neuropsychiatr Dis Treat 2015 -1 11: 2793-9 |
| PMID | 26604763 |
| Title | Association study of sepiapterin reductase gene promoter polymorphisms with schizophrenia in a Han Chinese population. |
| Abstract | Sepiapterin reductase participates in the biosynthesis of tetrahydrobiopterin, which plays very important roles in the pathogenesis of schizophrenia via dysregulation of neurotransmitter systems. Here, two single nucleotide polymorphisms (rs1876487 and rs2421095) in the promoter region of SPR were genotyped in 941 schizophrenic patients and 944 controls in a Han Chinese population using the SNaPshot technique. No significant differences were found in the distribution of alleles or genotypes of the two single nucleotide polymorphisms (SNPs) between schizophrenic patients and controls (all P>0.05). Likewise, no haplotype was found to be associated with schizophrenia. However, sex-stratified analysis revealed that the frequencies of the A allele of rs1876487 and the A-A (rs2421095-rs1876487) haplotype were all significantly different between schizophrenia and controls in females (P=0.040 and P=0.033, respectively), but not in males. Additionally, luciferase reporter gene assays revealed that the A-A haplotype had significantly higher SPR transcriptional activity compared with the A-C haplotype in SH-SY5Y cells. Our data indicate that the two SNPs do not influence the risk of schizophrenia when using the total sample, but the A allele of rs1876487 and the A-A haplotype may contribute to protective roles for schizophrenia in females. |
| SCZ Keywords | schizophrenia, schizophrenic |
| 9 | Psychiatry Res 2015 Jul 228: 95-9 |
| PMID | 25977072 |
| Title | Alterations in plasma vascular endothelial growth factor levels in patients with schizophrenia before and after treatment. |
| Abstract | Vascular endothelial growth factor (VEGF), a potent angiogenetic factor, is a known neurotrophic factor. In this study, we examined plasma levels of VEGF in 50 patients with schizophrenia (SPR) and 50 healthy control subjects. We also explored any changes in plasma VEGF levels after 6-week treatment with antipsychotic agents in patients with schizophrenia. All subjects with schizophrenia were either medication-naïve or medication-free for at least 4 weeks before assessment. Plasma VEGF levels in all subjects were significantly correlated with smoking duration, which was considered to be a significant covariate. Pre-treatment plasma VEGF levels in patients with schizophrenia were significantly lower than those in healthy controls. Post-treatment VEGF levels were significantly increased in patients with schizophrenia. Plasma VEGF levels in patients with schizophrenia did not exhibit significant correlation with the total or subscale scores of the Positive and Negative Syndrome Scale (PANSS) either at baseline or at the end of the 6-week treatment. In conclusion, our findings reveal that plasma VEGF levels before treatment were lower in patients with schizophrenia and that their VEGF levels increased after treatment. Thus, VEGF may have a neuroprotective role in the improvement of schizophrenia or in the treatment effects of antipsychotics. |
| SCZ Keywords | schizophrenia, schizophrenic |
| 10 | Neurosci. Lett. 2015 Mar 589: 126-31 |
| PMID | 25595562 |
| Title | Diagnostic utility of quantitative EEG in un-medicated schizophrenia. |
| Abstract | The aim of the current study was to evaluate the quantitative electroencephalography (QEEG) characteristics of patients with un-medicated schizophrenia (SPR) and to investigate the diagnostic utility of QEEG in assessing such patients during resting conditions. The subjects included 90 patients with schizophrenia and 90 normal controls. Spectral analysis was performed on the absolute power of all of the electrodes across five frequency bands following artifact removal. We conducted a repeated-measures ANOVA to examine group differences within the five frequency bands across several brain regions and receiver operator characteristic (ROC) analyses to examine the discrimination ability of each frequency band. Compared with controls, patients with schizophrenia showed increased delta and theta activity and decreased alpha 2 activity, particularly in the frontocentral area. There were no significant differences in the alpha 1 and beta activity. The ROC analysis performed on the delta frequency band generated the best result, with an overall classification accuracy of 62.2%. The results of this study confirmed the characteristics of the QEEG power in un-medicated schizophrenia patients compared with normal controls. These findings suggest that a resting EEG test can be a supportive tool for evaluating patients with schizophrenia. |
| SCZ Keywords | schizophrenia, schizophrenic |
| 11 | IEEE Trans Neural Syst Rehabil Eng 2016 Apr -1: -1 |
| PMID | 27071182 |
| Title | Abnormal Neural Oscillations in Schizophrenia Assessed by Spectral Power Ratio of MEG during Word Processing. |
| Abstract | This study investigated spectral power of neural oscillations associated with word processing in schizophrenia. Magnetoencephalography (MEG) data were acquired from 12 schizophrenia patients and 10 healthy controls during a visual word processing task. Two spectral power ratio (SPR) feature sets: the band power ratio (BPR) and the window power ratio (WPR) were extracted from MEG data in 5 frequency bands, 4 time windows of word processing, and at locations covering whole head. Cluster-based nonparametric permutation tests were employed to identify SPRs that show significant between-group difference. Machine learning based feature selection and classification techniques were then employed to select optimal combinations of the significant SPR features, and distinguish schizophrenia patients from healthy controls. We identified 3 BPR clusters and 3 WPR clusters that show significant oscillation power difference between groups. These include the theta/delta, alpha/delta and beta/delta BPRs during base-to-encode and encode time windows, and the beta band WPR from base to encode and from encode to post windows. Based on 2 WPR and 1 BPR features combined, over 95% cross-validation classification accuracy was achieved using 3 different linear classifiers separately. These features may have potential as quantitative markers that discriminate schizophrenia patients and healthy controls; however, this needs further validation on larger samples. |
| SCZ Keywords | schizophrenia, schizophrenic |