PubMed Health⌕ Search

Biomedical subjects

Iu B Iurov

Publications and source records attributed to Iu B Iurov.

At least 19 recordsLinked to original sources
PubMed2006

[Variations of heterochromatic chromosomal regions and chromosome abnormalities in children with autism: identification of genetic markers in autistic spectrum disorders].

In the present study, the cytogenetic and molecular cytogenetic analysis of 90 children with autism and their mothers (18 subjects) was carried out. Chromosome fragility and abnormalities were found in four cases: mos 47,XXX[98]/ 46,XX[2]; 46,XY,r(22)(p11q13); 46,XY,inv(2)(p11.2q13),16qh-; 46Y,fra(X)(q27.3)16qh-. Using C-banding and quantitative fluorescent in situ hybridization (FISH), the significantly increased incidence of heterochromatic region variation was shown in autism as compared to the controls (48 and 16%, respectively). Pericentric 9phqh inversion was not characteristic of the patients with autism whereas heterochromatic variations 1phqh, 9qh+ and 16qh- were more frequent in autism (p<0,05). Basing on the data obtained, a possible role of position effect in autism pathogenesis as well as a potential of heterochromatic region variation analysis for the search of biological markers of autistic spectrum disorders are discussed.

Adolescent↗
PubMed2005

[Diagnosis of numerical chromosomal aberrations in the cells of spontaneous abortions by multicolor fluorescence in situ hybridization (MFISH)].

According to different estimates, as high as 15-20% of all the pregnancies result in spontaneous abortions (SA) at different gestational periods. Identification of abnormalities leading to SA is of great importance for practical medicine, mainly for medical genetic counseling of married couples with impaired reproductive function. The diagnosis of chromosomal aberrations on the basis of SA materials is known to have a number of methodological difficulties. The present paper deals with the identification of numerical anomalies in the SA material by multicolor fluorescence in situ hybridization (MFISH). This technique using an original collection of DNA probes for chromosomes 1, 9, 13/21, 14/22, 15, 16, 18, X, and Y was applied to the study of chromosomal aberrations in 224 spontaneous abortion specimens. Numerical chromosomal aberrations were found in 122 (54.5%) cases. The cells of all the studied specimens exhibited aneuploidy of chromosome X in 17% cases; chromosome 16 in 12%, chromosomes 13/21 in 5.8%, chromosomes 14/22 in 4.9%, chromosomes 9 and 18 in 1.3% (each), chromosome 15 in 0.9%, chromosome 1 in 0.45%. Polyploidy was detected in 13.3% of cases; concomitant abnormalities were found in 7 cases. Analysis of the findings has led to the conclusion that MFISH can be successfully used in the diagnosis of numerical chromosomal aberrations of CA cells.

Abortion, Spontaneous↗
PubMed2005

[Quantitative analysis of fluorescence in situ hybridization (FISH) signals for molecular cytogenetic diagnosis].

Molecular cytogenetic diagnosis of chromosomal aberrations, by using fluorescence in situ hybridization (FISH) requires the introduction of quantitative approaches to estimating hybridization signals. Specifically, this estimation is required for the differentiation of monosomy and for the superposition of the signals in the diagnosis of mosaic forms of chromosomal syndromes, as well for the determination of the parental origin of homologous chromosomes. The present paper proposes an approach to rapidly estimating FISH signals, based on image capture by a CCD digital chamber and a fluorescence microscope, and to measuring the intensity of hybridization signals. This approach has been shown to be highly effective in differentiating the parent origin of chromosomes, by applying original chromosome-specific DNA tests. It has been successfully used in the study of numerical chromosomal aberrations in various biological materials. By taking into account the findings and as well as earlier described quantitative FISH analyses applied to basic studies, the authors discuss whether the quantitative FISH analyses can be used for the molecular cytogenetic diagnosis of hereditary diseases.

Adult↗
PubMed2002

[Genotype-phenotype correlations in Rett syndrome: the study of Russian cohort of patients].

Rett syndrome (RTT) is a severe neurodevelopmental disorder caused by mutations in methyl-CpG-binding protein 2 gene (MECP2). We carried out a mutations analysis in Russian cohort of patients with RTT. MECP2 mutations were found in 23 of 28 RTT girls and one boy (82%). Thirteen different types of mutations have been identified: 6 nonsense, 5 missense and 2 deletions in MECP2 gene. In typical RTT form, most frequent mutations were R255X (5 cases) and T158M (4 cases). A boy with classical clinical picture of RTT had R270X mutation. Skewed inactivation of chromosome x has been found in 2 of 27 RTT girls with classical RTT form and "forme fruste". The data obtained imply possible correlations between genotype and phenotype in RTT.

Child↗
PubMed2001

[Serotonin type 2a (5-HTR2A) receptor gene polymorphism and personality traits in patients with endogenous psychoses].

Genetic polymorphism of the serotonin receptor (5-HTR2A) gene has been reported to be associated with the expression of clinical signs characteristic of major psychoses, including schizophrenia and affective disorders. In this study, personality traits of patients with these diseases and the associations of these traits with 5-HTR2A allelic polymorphisms were studied. It was demonstrated that schizophrenic and affective patients with the 2/2 genotype of serotonin receptor had lower scores on the anxiety scale and on the anxiety-related hypochondriasis and neuroticism scales than subjects with the 1/1 and 1/2 genotypes.

Adolescent↗
PubMed2001

[Molecular genetic polymorphism of the genes of neurotransmitter systems in schizophrenics with early manifestation of the disease].

Molecular-genetic polymorphism of genes-candidates was investigated: the genes of serotonin receptor--type 2a (HTR2A), dopamine receptor gene--type 2, serotonin transporter (5HTTLPR). Thirty one schizophrenic patients whose age was 12.6 +/- 3.6 years at the onset of the disease and 208 patients whose age was 23.5 +/- 6.7 years at the onset of the disease were examined. The frequencies of HTTLPR and DRD2 genotypes differed insignificantly in both groups. The distribution of 5HTR2A genotypes in the schizophrenic group with an early manifestation of the disease differed from that with a later manifestation significantly (chi 2 = 6.27; df = 2; p = 0.044). The relative risk (odds ratios) was 7.9 with 95% significance interval 1.008-61.94; p = 0.045. The severity of the disease and a positive family history were also examined in A2A2 genotype carriers. A positive family history was found in 9 (52.9%) of the 17 schizophrenics with an early manifestation and only in 15 (21.1%) of 71 patients of the similar group with a later one. Assessment of the clinical symptoms revealed that the total scores by the negative symptomatology subscale (PANSS) was higher in the patients with an early manifestation than in those with later one; but these differences did not achieve the significance level. These and earlier findings lead to the conclusion that A2A2 genotype was more frequently observed in the patients with more pronounced negative symptoms and high hereditary burden, which suggests that the A2A2 genotype is associated with an early onset.

Adult↗
PubMed2001

[Molecular cytogenetic studies of chromosomal abnormalities and disorders in nervous and mental diseases: search for biological markers for diagnosis].

Molecular cytogenetic and cytogenetic studies of chromosomal disorders in patients with nervous and mental disorders were conducted using currently available approaches, including fluorescence in situ hybridization (FISH) with an original collection of centromeric, telomeric, region-specific DNA probes. A novel in situ hybridization protocol for rapid (15-30 min) chromosomal detection procedure and directly fluoresceinated DNA probes are recommended for use in mental retardation and congenital malformations. Chromosomal abnormalities could be detected in postnatal cases with chromosomal structural rearrangements, aneuplodies of gonosomes (including mosaicisms) and autosomes (including marker chromosomes). Molecular cytogenetics (or FISH diagnosis) can be used when classical cytogenetic methods are insufficient. The authors' experience shows that FISH should be utilized only as an adjunctive test for classical cytogenetic studies when banding techniques are ineffective; cytogenetic methods should be utilized for the preclinical diagnosis of Rett's syndrome. Detection by original probes gives an additional possibility in FISH analysis. Molecular cytogenetic methods are shown to provide a rapid accurate approach to studying and diagnosing chromosomal anomalies and disorders in mental retardation with congenital malformations and Rett's syndrome in children and to exploring aneuploidies in the postmortem cell samples from schizophrenic patients.

Adult↗
PubMed2000

[Serotonin receptor gene allele polymorphism (5HTR2A) and clinical pathogenetic characteristics in patients with schizophrenia and schizophrenia spectrum disorders].

Serotonin receptor 5HTR2A gene polymorphism was reported to be associated with psychiatric disorders, in particular schizophrenia, in numerous studies. This study aimed to analyze a possible association between 5HTR2A gene polymorphism and clinical and pathogenetic characteristics in schizophrenia and schizophrenia spectrum disorders. We studied 209 individuals with schizophrenia and related disorders (107 male and 102 female, mean age 34.7 +/- 17.2 years) and 116 healthy controls (44 males, 72 females, mean age = 33.6 +/- 14.4 years). Diagnoses were made according diagnostic criteria of ICD-10. Positive and Negative Symptoms Scale (PANSS) assessed clinical symptoms. Significant difference (p < 0.01) was found for 5HTR2A genotype distribution between affected and control groups. The frequencies of genotypes A1A1, A1A2 and A2A2 for schizophrenia were 13.3%, 44.0% and 42.7%, respectively, versus 33%, 47% and 27% in controls. These results support the evidence for association between 5HTR2A A2A2 genotype and schizophrenia. Schizophrenics with A2A2 genotype were characterized by significantly higher mean values of the PANSS negative symptoms subscale than those with A1A1 genotype (22.6 vs 17.8; p < 0.05) and, consequently, by majority of deficit patients and patients with more severe forms of schizophrenia. Patients with A1A1 genotype were younger compare to those with A2A2 genotypes and had the least familial factors (35.7% vs 46.1%). In agreement with the results obtained in the study the 5HTR2A gene polymorphism appears to be considered as additional diagnostic or prognostic trait in the medical genetic studies of schizophrenia.

Adolescent↗
PubMed2000

[Development of an original computer program FISHMet: use for molecular cytogenetic diagnosis and genome mapping by fluorescent in situ hybridization (FISH)].

Original software FISHMet has been developed and tried for improving the efficiency of diagnosis of hereditary diseases caused by chromosome aberrations and for chromosome mapping by fluorescent in situ hybridization (FISH) method. The program allows creation and analysis of pseudocolor chromosome images and hybridization signals in the Windows 95 system, allows computer analysis and editing of the results of pseudocolor hybridization in situ, including successive imposition of initial black-and-white images created using fluorescent filters (blue, green, and red), and editing of each image individually or of a summary pseudocolor image in BMP, TIFF, and JPEG formats. Components of image computer analysis system (LOMO, Leitz Ortoplan, and Axioplan fluorescent microscopes, COHU 4910 and Sanyo VCB-3512P CCD cameras, Miro-Video, Scion LG-3 and VG-5 image capture maps, and Pentium 100 and Pentium 200 computers) and specialized software for image capture and visualization (Scion Image PC and Video-Cup) have been used with good results in the study.

Child↗
PubMed2000

[Current methods of molecular cytogenetics in pre- and postnatal diagnosis of chromosome aberrations].

Progress in prevention of chromosome aberrations is due to utilization of molecular cytogenetic diagnostic methods. The purpose of this trend of clinical cytogenetics is development and utilization of new highly effective methods for analysis of chromosome aberrations. Molecular cytogenetic methods (fluorescent in situ hybridization-FISH) are used for pre- and postnatal identification of chromosome aberrations in mentally retarded children and congenital diseases. These studies are carried out after classical cytogenetic analysis, if it proves to be of no avail. FISH diagnosis pre- and postnatally detects autosomal trisomy, gonosome aneuploidy (including mosaic forms), marker chromosomes, structural chromosome aberrations, including fragile X chromosome syndrome. Rapid (15-30 min) FISH with an original collection of centromere, telomere, and site-specific DNA probes (plasmid, cosmid, PAC and YAC clones) is recommended for molecular cytogenetic diagnosis. FISH diagnosis is an effective complex of methods for pre- and postnatal identification of chromosome aberrations and a necessary supplement to classical cytogenetic diagnosis. Molecular studies of chromosome aberrations are significant for theoretical and applied studies, for they help detect patients with specific chromosome syndromes from a vast group of children with undifferentiated mental retardation and congenital diseases.

Aneuploidy↗
PubMed1999

[Molecular cytogenetic pre- and postnatal diagnosis of chromosomal abnormalities].

Molecular cytogenetic studies in the prenatal and postnatal identification of chromosomal anomalies in children with mental retardation and congenital developmental malformations are discussed. Molecular cytogenetic techniques, such as fluorescence in situ hybridization (FISH) are employed after the use of classic cytogenetic studies. FISH diagnosis is recommended to apply in the cases when classic cytogenetic methods are not beneficial: post- and prenatal autosomal trisomies; gonosomal aneuploidies, including mosaic forms; marker chromosomes; structural chromosomal anomalies, including fragile X syndrome. The authors' experience showed that (1) FISH should be utilized only as an adjunctive test for classical cytogenetic studies when banding techniques are ineffective; (2) FISH confirms a cytogenetic diagnosis; (3) multicolored probe detection gives an additional possibility in the FISH analysis. The findings demonstrate that molecular cytogenetic methods provide a rapid accurate approach to investigating and diagnosing chromosomal anomalies. Molecular cytogenetic diagnosis allows a more correct correlation of chromosomal abnormalities to be shown with a clinical picture and assists in identifying new chromosomal syndromes in children with undifferentiated forms of mental retardation and congenital malformations.

Chromosome Aberrations↗
PubMed1998

[Study of alpha-satellite DNA in cosmid libraries, specific for chromosomes 13, 21, and 22, using fluorescence in situ hybridization].

Fluorescent in situ hybridization (FISH) was employed in mapping the alpha-satellite DNA that was revealed in the cosmid libraries specific for human chromosomes 13, 21, and 22. In total, 131 clones were revealed. They contained various elements of centromeric alphoid DNA sequences of acrocentric chromosomes, including those located close to SINEs, LINEs, and classical satellite sequences. The heterochromatin of acrocentric chromosomes was shown to contain two different groups of alphoid sequences: (1) those immediately adjacent to the centromeric regions (alpha 13-1, alpha 21-1, and alpha 22-1 loci) and (2) those located in the short arm of acrocentric chromosomes (alpha 13-2, alpha 21-2, and alpha 22-2 loci). Alphoid DNA sequences from the alpha 13-2, alpha 21-2, and alpha 22-2 loci are apparently not involved in the formation of centromeres and are absent from mitotically stable marker chromosomes with a deleted short arm. Robertsonian translocations t(13q; 21q) and t(14q; 22q), and chromosome 21p-. The heterochromatic regions of chromosomes 13, 21, and 22 were also shown to contain relatively chromosome-specific repetitive sequences of various alphoid DNA families, whose numerous copies occur in other chromosomes. Pools of centromeric alphoid cosmids can be of use in further studies of the structural and functional properties of heterochromatic DNA and the identification of centromeric sequences. Moreover, these clones can be employed in high-resolution mapping and in sequencing the heterochromatic regions of the human genome. The detailed FISH analysis of numerous alphoid cosmid clones allowed the identification of several new, highly specific DNA probes of molecular cytogenetic studies--in particular, the interphase and metaphase analyses of chromosomes 2, 9, 11, 14, 15, 16, 18, 20, 21-13, 22-14, and X.

Chromosomes, Human, Pair 13↗
PubMed1998

[Cytogenetic and molecular genetic diagnostics of Rett syndrome in children].

Rett syndrome in 32 children (31 girls and 1 boy) was diagnosed according to International association on Rett syndrome. The phenomenon of the presence of special type of late-replicating chromosome X (type C) was revealed. This phenomenon may be recommended as a diagnostic test for both preclinical periods of development of the disease and in atypical cases of Rett syndrome.

Child↗