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Synaptosomal protein SNAP-25 is involved in the process of transmitting nerve spikes in the CNS and in the consolidation of memory traces in the hippocampus. Two independent studies have demonstrated associations between SNAP-25 gene polymorphisms and intellectual functions in a group of mentally healthy subjects and patients with schizophrenia. The aim of the present work was to perform a comparative study of the association between the MnlI polymorphism of SNAP-25 and cognitive functions (verbal memory, attention/executive functions) in 66 patients with endogenous psychoses, 75 of their mentally healthy relatives, and 136 healthy control subjects. Statistical analysis showed that the effectiveness of performing cognitive tests was significantly affected by group assignment (p = 0.00001) and genotype (p = 0.012). The interaction between genotype and group assignment also had an influence (p = 0.02). In all groups, carriers of the TT genotype had worse measures than carriers of other genotypes. The similar nature of the influences of the MnlI polymorphism on variations in measures in all groups indicates that this gene is related to overall intellect.

Platelet serotonin content in patients in the acute period of stroke is an important index of clinical changes during the post stroke period as well as a predictor of development of mental disorders. We studied the association between two polymorphisms (5-HTTLPR and Val66Met BDNF) and the platelet serotonin content in 47 patients with stroke. We also investigated the moderating effect of genetic variants on the association between platelet serotonin content and development of affective and anxiety disorders in stroke patients in the acute period of stroke. The interaction effect of two polymorphisms on levels of platelet serotonin was found. The lowest level was observed in patients with the diplotype LL*ValVal, the highest level--in the group of patients with the LL genotype and genotypes containing at least one copy of a Met allele. No moderating effect of genetic variants on the relationship between serotonin content and affective or anxiety disorder was found.

Genetic factors are thought to contribute to schizotypal dimensions. Recently, a number of genetic variants associated with schizotypal traits in psychiatrically healthy people have been found. Authors reported earlier the association between the SERT 5-HTTLPR polymorphism and schizotypal traits measured with MMPI. The present study aimed at the replication of association on a larger sample using other questionnaires and methods of data analysis. The sample comprised 657 people from the Russian population. MMPI, SPQ-74 and TCI-125 were used to measure personality traits. Based on the results of psychological testing, the sample was divided into high risk and control groups. For MMPI, the high risk group included people with the elevation on scale Schizophrenia, for SPQ-74 - people with a total score more than 25 and for TCI-125 - people with lower scores on scale Cooperation and higher scores on Self-Transcendence. In all high-risk groups assessed by different psychological instruments, the frequency of the SS 5-HTTLPR genotype was significantly lower as compared to the corresponding control groups. MANCOVA also showed that individuals with the SS genotype had lower scores on scales related to schizotypal traits. Thus, we have confirmed our previous results on the association between the 5-HTTLPR polymorphism and schizotypal traits in psychiatrically healthy subjects.

The synaptosomal-associated protein (SNAP-25) plays an integral role in synaptic transmission and in memory consolidation in the hippocampus. Recently an association between SNAP-25 gene polymorphism and cognitive ability has been reported in two independent studies of healthy people and patients with schizophrenia. Authors carried out an association study of MnlI SNAP-25 polymorphism and performance on neurocognitive tests measuring verbal memory, attention/executive functions in 66 patients with major psychosis, 75 their relatives and 136 controls. MANCOVA revealed a significant effect of group (small er, Cyrillic=0,00001) and genotype (small er, Cyrillic=0,012) as well as an interaction effect between group and genotype (small er, Cyrillic=0,02) on the performance on neurocognitive tests. Carriers of the TT genotype performed worse on the most tasks compared to other genotypes. The similar character of the MnlI SNAP-25 polymorphism effect on the variability of neurocognitive traits in all groups suggests the relationship between this gene and general cognitive ability.

Serotonin type 2A receptors (5-HTR2A) have long been implicated in schizophrenia pathology. A decreased number of these receptors were found in postmortem brain studies of schizophrenic patients as well as in experiments using neuroimaging techniques. Molecular genetic studies revealed that the T102C polymorphism of the 5-HTR2A gene is associated with schizophrenia, with the CC genotype frequency being higher in patients compared to healthy controls. However the association was not confirmed in all studies. We carried out a replication study, which aimed at searching for association between this polymorphism and schizophrenia in a large samples of patients (n=919), their psychiatrically well first-degree relatives (n=330) and screened controls (n=500). The C allele and the CT+CC genotype frequencies were significantly higher in patients than in controls (chi2=5.1; df=1; p=0.02; OR 1.2, 95% CI 1.0-1.4) and chi2=5.4; df=1; p=0.02; OR 1.4, 95% CI 1.1-1.8 respectively). In a family-based study, the transmission disequilibrium test (TDT) and the family-based association test (FBAT) did not show a preferential transmission of any allele. In conclusion, our replication study provides further evidence for association between the 5-HTR2A receptor T102C polymorphism and schizophrenia.

To clarify nosologic differences between schizoaffective psychosis (SAP) and attack-like progressive schizophrenia at molecular-genetic level, the genetic polymorphism of serotonin receptor type 2A (5HTR2A), serotonin transporter (5-HTTLRP), and brain-derived neurotrophic factor (BDNF) was studied in 563 patients with schizophrenia (mean age 37.7+/-14.4 years, age at disease onset 26.7+/-11.4 years), and 171 patients with SAP (mean age 30.7+/-11.6 years, age at disease onset 24.9+/-8.5 years). The control group consisted of 536 psychiatrically well subjects. Clinical symptoms and personal features were evaluated as well. By comparison with schizophrenic patients, those with SAP were featured by subtle negative symptoms and personality changes that supported the evidence that SAP is a disorder with a favorable outcome. Molecular-genetic studies revealed higher frequencies of S allele and SS genotype (5-HTTLPR polymorphism), which are thought to be associated with depression and depressive symptoms, and higher frequency of BDNF genotypes, containing Met allele, in combination with 5-HTTLRP genotypes containing L allele, in patients with SAP as compared to the schizophrenic group. C allele and CC genotype (T102C 5-HTR2A polymorphism) frequencies were higher in both groups of patients vs. controls. In conclusion, the results confirm the concept considering SAP an independent nosologic category.

Polymorphisms of the following genes (dopamine receptors D2 (Taq1A), D3 (Ser/Glu), D4 (VNTR, -521T/C, -616 G/C, -809A/G), catechol-O-methyltransferase, serotonin receptor type 2A (T102C), serotonin transporter (5-HTTLPR small i, Cyrillic VNTR) and brain-derived neurotrophic factor) have been studied in 260 men with juvenile endogenous attack-like psychoses and 145 age- and sex-matched controls. Type of psychopathological syndrome, PANSS scores and cognitive traits have been assessed. Only the T102C 5-HTR2A polymorphism was associated with some changes in the progress of this type of psychosis. As compared to the TT genotype, patients with 1 or 2 copies of the C allele were characterized by the absence of or less pronounced affective symptoms and more cognitive impairment that implies severity of illness. Moreover, the higher frequency of the C allele was found in the group of patients with chronic course of disease. In conclusion, the T102C polymorphism can be taken into account in prediction of juvenile endogenous attack-like psychosis.

Polymorphic marker Ser9Gly of dopamine receptor D3 gene is considered perspective for associative studies of schizophrenia. Allele and genotype frequency of this polymorphism were studied in different ethnic groups of schizophrenic patients as well as the attempts have been made to reveal an association with clinical presentations of the disease. However, the results are inconsistent. The present study aimed at investigating Ser9Gly DRD3 gene polymorphism in Russian sample of schizophrenic patients. One hundred and fifty patients with ICD-10 diagnosis of schizophrenia (broad definition), 69 male and 81 female, aged 34.8+/-13.87 years, age at disease onset 24.3+/-9 years, have been examined. Control group consisted of 150 healthy subjects without family history of schizophrenia, 60 male and 90 female, aged 32.7+/-13.5 years. No between-group differences have been found for Ser9Gly DRD3 allele and genotype frequencies. However, a frequency of homozygous genotype Gly/Gly was significantly higher in female patients, comparing to female controls (p=0.038 Yate's corrected, OR 9. CI 0.95% 1.0-79.5). A role of sex-dependent association between Ser9Gly DRD3 polymorphism and schizophrenia is discussed.

The effect of bleomycin (Blm) on DNA synthesis has been studied in a synchronous culture of human embryonic lung cells. The data obtained suggest that in the Blm presence in a medium (20 micrograms/ml) DNA synthesis initiation in new replicons is suppressed. The Blm action at different S-phase intervals has been shown to inhibit DNA synthesis unequally. Four discrete time intervals have been singled out in the course of the 10-hr S-phase in which a grouped initiation of replicon portions can be supposed. Together with the data on DNA replication in large-size replicon units (50-500 microns), the obtained results account well for the uneven DNA synthesis in S-phase, manifested by 3 or 4 peaks of [3H]-thymidine incorporation in pulse-labelled cells.