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S G Vorsanova

Publications and source records attributed to S G Vorsanova.

At least 37 records · Page 2Linked to original sources
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↗
PubMed1996

Cytogenetic and molecular-cytogenetic investigation of Rett syndrome: analysis of 31 cases.

Rett syndrome (RS) is a progressive encephalopathy restricted to the female sex. In the present study we investigated 30 females and one male with RS by cytogenetic and molecular-cytogenetic methods. We failed to identify any chromosomal rearrangements within the female groups and no correlation between fra(X)(p22) and RS in either the female group or the male. The boy with RS has karyotype 46,XY/47,XXY with abnormal cell clone (47,XXY) in 6-12% of his lymphocytes (revealed by fluorescence in situ hybridization analysis (FISH) of interphase cells with chromosome X-specific DNA probe). Our results indicated a possible connection between RS and X-chromosome replication disturbance. A late-replicating X-chromosome with a specific banding pattern (type 'C') has been observed in RS patients only. We propose to analyse the X-chromosome replication pattern as a test for confirmation of RS at preclinical diagnosis.

Adolescent↗
PubMed1996

High resolution multicolor fluorescence in situ hybridization using cyanine and fluorescein dyes: rapid chromosome identification by directly fluorescently labeled alphoid DNA probes.

We tested DNA probes directly labeled by fluorescently labeled nucleotides (Cy3-dCTP, Cy5-dCTP, FluorX-dCTP) for high resolution uni- and multicolor detection of human chromosomes and analysis of centromeric DNA organization by in situ hybridization. Alpha-satellite DNA probes specific to chromosomes 1, 2, 3, 4 + 9, 5 + 19, 6, 7, 8, 10, 11, 13 + 21, 14 + 22, 15, 16, 17, 18, 20, 22, X and Y were suitable for the accurate identification of human chromosomes in metaphase and interphase cells. Cy3-labeled probes had several advantages: (1) a high level of fluorescence (5-10 times more compared with fluorescein-labeled probes); (2) a low level of fluorescence in solution, allowing the detection of target chromosomes in situ during hybridization without the washing of slides; and (3) high resistance to photobleaching during prolonged (1-2 h) exposure to strong light, thus allowing the use of a high energy mercury lamp or a long integration time during image acquisition in digital imaging microscopy for the determination of weak signals. For di- and multicolor fluorescence in situ hybridization (FISH), we successfully used different combinations of directly fluorophorated probes with preservation of images by conventional microscopy or by digital imaging microscopy. FluorX and Cy3 dyes allowed the use of cosmid probes for mapping in a one-step hybridization experiment. Cyanine-labeled fluorophorated DNA probes offer additional possibilities for rapid chromosome detection during a simple 15-min FISH procedure, and can be recommended for basic research and clinical studies, utilizing FISH.

Carbocyanines↗
PubMed1996

Rapid chromosomal analysis of germ-line cells by FISH: an investigation of an infertile male with large-headed spermatozoa.

A rapid fluorescence in-situ hybridization (FISH) technique was used for direct chromosomal analysis on germ cells from an infertile male with large-headed spermatozoa. The interphase chromosomes were fluorescently-labelled using an extremely bright cyanine dye during a 5-15 min FISH procedure. Germ cells were analysed using a battery of chromosome-specific DNA probes in several consecutive rapid FISH experiments. It was found that the majority of large-headed spermatozoa contained a diploid chromosome number probably due to errors in meiosis I or II divisions, whereas the majority of spermatozoa with normal sized heads are haploid and may be utilized for selective in-vitro fertilization procedures. Rapid FISH may be useful for the detection of major chromosomal aneuploidies in germ cells as an alternative technique to standard or multicolour FISH, and may find an additional application for the chromosomal analysis of human preimplantation embryos.

Adult↗
PubMed1995

Prenatal diagnosis of trisomy 21 using interphase fluorescence in situ hybridization of post-replicated cells with site-specific cosmid and cosmid contig probes.

Interphase fluorescence in situ hybridization (FISH) with chromosome 21-specific cosmid clones was used to identify trisomy 21 in cultured and uncultured amniotic cells. Two novel site-specific cosmid clones (regions 21q22 and 21qtel) were compared with a cosmid contig (Zheng et al., 1992). Correct identification of chromosome 21 copy number was made in 65-75 per cent of trisomic cells and in 70-75 per cent of normal disomic cells by using all the tested probes. However, the chromosome 21-specific telomeric probe (cos 17F8) showed the best results due to more intense and clearly visible hybridization. Utilization of a directly fluorophorated telomeric probe using Cy3-dCTP and FluorX-dCTP allows accurate detection of chromosome 21 in a fast 'one-step' FISH procedure on uncultured interphase nuclei. In addition, we compared the efficacy of FISH analysis for the total population of interphase cells and cells in the post-replication (late S, G2) periods of the cell cycle. Selective scoring of cells in the post-replicative period (showing a pair of hybridization signals on each chromatid of the replicated interphase chromosome) increased the number of informative nuclei by up to 95-97 per cent. This approach allows cells with overlapping chromosomes, artificial double hybridization signals on separate chromatids in interphase chromosomes, background hybridization, and polyploid cells to be analysed. Application of directly labelled telomeric cosmid probes and integral analysis of hybridized nuclei in the pre- and post-replication periods of the cell cycle may help to further improve the prenatal detection of trisomy 21.

Amniotic Fluid↗
PubMed1995

Analysis of pericentromeric chromosome 21 specific YAC clones by FISH: identification of new markers for molecular-cytogenetic application.

Fluorescence in situ hybridization (FISH) of chromosome 21 specific yeast artificial chromosome (YAC) clones after Alu-PCR (polymerase chain reaction) amplification has been used to find new region-specific DNA probes for the heterochromatic region of chromosome 21. Six overlapping YAC clones from a pericentromeric contig map (region 21cen-21q11) were analyzed. Four YAC clones were characterized as hybridizing to several chromosomal locations. They are, therefore, either chimeric or shared by different chromosomes. Two of them containing alphoid satellite DNA, are localized at the centromeric regions of chromosomes 13 and 21 (clone 243A11), and on 13cen, 21cen and 1q3 (clone 781G5); the two others are localized at both 21q11 and 13q2 (clone 759D3), and at 18p (clone 770B3). Two YACs were strongly specific for chromosome 21q11 only (clones 124A7 and 881D2). These YACs were used effectively as probes for identifications of chromosome 21 during metaphase and interphase analysis of 12 individuals, including three families with Down syndrome offspring, and 6 aminocyte samples. The location of YAC clones on 21q11 close to the centromeric region allows the application of these clones as molecular probes for the analysis of marker chromosomes with partial deletions of the long arm as well as for pre- and postnatal diagnosis of trisomy 21 when alphoid or more distal region-specific DNA probes are uninformative. Overlapping YAC clones covering human chromosome 21q may be systematically used to detect a set of band-specific DNA probes for molecular-cytogenetic application.

Base Sequence↗
PubMed1994

Rapid identification of marker chromosomes by in situ hybridization under different stringency conditions.

Six metacentric non-satellite chromosome markers and 4 satellite markers of unknown origin were discovered by routine cytogenetic analysis. These markers were then investigated by isotopic and nonisotopic (FISH) in situ hybridization. In order to determine the origin of small marker chromosomes, a special protocol involving sequential application of defined alphoid and 'classical' satellite DNA probes with chromosome specificity was used. In situ hybridization under low stringency conditions has been performed with DNA probes specific for 4 groups of chromosomes. After preliminary analysis and determination of the possible origin of these marker chromosomes, DNA probes with high chromosome specificity were used under high stringency conditions. Marker chromosomes were found to be derivatives of chromosomes 7, 9 (3 cases), 13, 14 or 22, 21 (2 cases), X and Y.

Chromosomes, Human↗
PubMed1991

[Method of diagnosing aneuploidies using in situ hybridization: analysis of interphase nuclei].

The possibility of determining chromosomal sex using in situ hybridization of X-specific alphoid DNA probe with interphase human nuclei is studied. Total number of nuclei under study being 14806, more than 85 percent of female ones and more than 95 per cent of male ones are shown to contain two and one grain clusters, respectively. The minor nuclear classes, i.e. containing other numbers of grain clusters, may reflect the effects of polyploidization and cluster aggregation resulting from spatial chromosome distribution. Therefore the positive analysis of sex chromosome constitution on the base of the applied method is possible.

Aneuploidy↗
PubMed1990

Translocation t(1;17)(q12;q25) with a clinical picture like of a proximal deletion of 1q: identification by in situ hybridization with chromosome 1-specific satellite DNA probes.

The authors report a case of a balanced 1;17 translocation with breakpoints located in the secondary constriction of chromosome 1. This translocation is associated with pathological symptoms similar to those observed following a proximal deletion of 1q. We request contact with colleques who have observed similar, or related, cases of translocation with breakpoints in heterochromatic regions of human chromosomes.

Child↗
PubMed1990

Preliminary results on the frequency of the delta F508 mutation in cystic fibrosis patients from the USSR.

The frequency of the delta F508 mutation in a sample of 29 cystic fibrosis (CF) families from the USSR is equal to 44.8%, in agreement with previously reported haplotype data. If confirmed on a larger sample of CF patients from the USSR, this result might be indicative of the presence of a larger heterogeneity of CF mutations in the Soviet population than in other European populations.

Cystic Fibrosis↗
PubMed1986

18p- syndrome: an unusual case and diagnosis by in situ hybridization with chromosome 18-specific alphoid DNA sequence.

A patient with an atypical clinical picture of 18p- syndrome is described. By the in situ hybridization technique we localized the chromosome 18-specific cloned repetitive sequence to metaphase chromosomes of the patient. The predominant hybridization of the probe was found in pericentromeric regions of homologous chromosomes 18. The amount of pericentromeric DNA measured by in situ hybridization differed between homologous chromosomes; and the number of radioactive grains was statistically greater in the normal chromosome 18 than in the aberrant chromosome 18p-. The results indicate that this probe may be useful in clinical cytogenetics for identification of aberrant chromosomes, localization of breakpoints, and studies of C-band DNA polymorphism of chromosome 18.

Abnormalities, Multiple↗