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Complex chromosomal aberrations in bone marrow cells of adult patients with myelodysplastic syndromes (MDS): frequency, mechanism of origin and clinical significance.
Rochlová, Kristina ; Zemanová, Zuzana (advisor) ; Novotná, Drahuše (referee)
Complex chromosomal aberrations occurs are described in approximately 20 % of patients with myelodysplastic syndrome (MDS) and are associated with a poor prognosis. Nevertheless, the mechanism and possible causes responsible for the emergence of these aberrations are not fully understood. There are two models describing the emergence of these aberrations, namely shattering of single chromosomes or their parts during the so-called cellular crisis (chromothripsis) and/or progressive accumulation of chromosomal aberrations during the course of the disease (clonal evolution). Using combination of cytogenomic methods we examined 61 samples of bone marrow from adult patients with MDS and a complex karyotype. Unbalanced aberrations with loss of genetical material were found in most cases. Chromosomes 5, 7 and 12 were most frequently involved in rearrangements. Clonal development, chromothripsis and both mechanism was detected in 26, 12 and 14 patients, respectively. Patients with deleted chromosome 5 included in complex karyotype had the shortest overall survival. The cause of emergence of complex aberrations did not affect survival. Cytogenomic analysis of complex aberrations allows detection of balanced and unbalanced changes and identification of important processes of tumorigenesis such as clonal...
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Application of cytogenetic and molecular cytogenetic methods in prenatal diagnosis
Rašpličková, Tereza ; Novotná, Drahuše (advisor) ; Zemanová, Zuzana (referee)
Foetal anomalies found on ultrasound increase the probability of occurrence of chromosomal abnormalities. They cause about one quarter of all abortions and stillbirths and many of inborn defects in newborns. Karyotype analysis is number one method in prenatal diagnosis whereas array CGH is often used as a verification and supplemental method. The aim of this work was to prove that array CGH gives additional chromosomal findings to karyotypes and could substitute conventional karyotyping as a primary examination method in foetuses with ultrasound findings. We examined 45 prenatal samples using both methods. These samples were referred for invasive examination because of abnormal ultrasound findings. Karyotype analyses found two abnormalities in two (4,4 %) patients and array CGH identified aberrations in five (11,1 %) foetuses whereas both anomalies detected by karyotypes were discovered by array CGH too. This means that array CGH identified about 6,7 % more aberrations than karyotype. Our results correspond with scientific articles which refer that array CGH should replace karyotype not only in postnatal examinations but even in prenatal diagnosis. Keywords: chromosomal aberrations, array CGH, karyotype, prenatal diagnosis, ultrasound
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Analýza aneuploidií a studium meiózy u oocytů metodou komparativní genomové hybridizace na DNA čipu
Kocur, Tomáš
Aneuploidy frequency increases with advanced female age and results in infertility or live birth of affected individuals. Aneuploidies occur mainly during female meiosis. Polar bodies biosied from oocytes after first and second meiosis were analyzed using array comparative genomic hybridization testing for all chromosomes. More than a half of tested oocytes were aneuploid. Aneuploidies as a result of nondisjunction in meio-sis II were slightly more frequent than meiosis I errors. Premature chromatide predivisi-on was absolutely predominant among errors occurring during meiosis I. Despite the fact that aneuploidies were detected for each chromosome, most aneuploidies were detected for small acrocentric chromosomes. Possible mechanisms of aneuploidy formation are discussed in context of information obtained by the means of animal biotechnologies at different species of mammals.
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