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    Determination of Allelic Deletion of Multiple Endocrine Neoplasm Type 1 (MEN1) Gene in Acute Myeloid Leukemia (AML) by Application of FISH-TSA Technique
    (Wiley-Liss, 2002) Acar, Hasan; Kaynak, Murat; Yakut, Tahsin; Uçar, Fahri; Egeli, Ünal
    We have used the single and dual color fluorescence in situ hybridization (FISH) technique combined with a new detection system, tyramide signal amplification (TSA), by using the multiple endocrine neoplasm type I (MEN1) gene and chromosome I I specific alpha satellite DNA probes for the study of the allelic deletion of the MEN1 gene. The MEN1 gene is a new tumor supressor gene and has been recently cloned on chromosome 11q13. FISH combined with the TSA detection system was performed on bone marrow interphase nuclei of 22 patients with acute myeloid leukemia (AML). The FISH-TSA analysis revealed the mono allelic deletion of the MEN1 gene in 4 out of 22 patients (18.18%), 2 of 9 AML-M2 patients (22.2%), 1 of 6 AML-M4 patients (16.6%), and I of 4 AML-M5 patients (25.0%). Our study indicates that allelic deletion of the MEN1 gene is not a major cause or a primary event in tumorigenesis of AML, although the long arm (q13 region) of chromosome 11 involves a chromosomal rearrangement in AML.
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    Evaluation of Relationship Between Chromosome 22 and p53 Gene Alterations and the Subtype of Meningiomas by the Interphase-Fish Technique
    (Wiley-liss, 2002) Yakut, Tahsin; Bekar, Ahmet; Doygun, Muammer; Acar, Hasan; Egeli, Ünal; Oğul, Erhan
    In this study, we investigated the relationship between genetic alterations such as chromosome 22 aneuploidy and p53 gene deletion, and the pathological types of meningioma of typical and aggressive forms. Thirty-four meningiomas (23 typical and 11 aggressive) were examined by application of fluorescence in situ hybridization (FISH) with chromosome 22 specific alpha satellite probe and a combination of p53 locus specific and chromosome 17 centromere specific alpha satellite probes, to evaluate the chromosome 22 aneuploidy and gain or loss of p53 gene along with chromosome 17. The results showed that, although chromosome 22 aneuploidy was seen in 7 out of 23 typical (30.4%) and 4 out of 11 aggressive meningiomas (36.3%), no p53 deletion was detected in typical meningiomas, and p53 deletion was detected in 3 out of 11 aggressive meningiomas (1 atypical and 2 malignant), which had recurrence. There were no simultaneous occurrences of p53 gene deletions between typical and aggressive meningiomas. The present findings indicate that the loss of chromosome 22 may be involved with tumorogenesis of typical and aggressive meningiomas, while p53 gene deletions may be involved with malignant progression and recurrence in the aggressive meningiomas.
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    Frequency of Recombinant and Nonrecombinant Products of Pericentric Inversion of Chromosome 1 in Sperm Nuclei of Carrier: by Fish Technique
    (Wiley-Liss, 2003) Yakut, Tahsin; Acar, Hasan; Egeli, Ünal; Kimya, Yalçın
    Meiotic segregation products of carriers with pericentric inversion are very important for assessing the risk of unbalanced forms and appropriate genetic counseling. We investigated the incidence of recombinant and nonrecombinant products of chromosome 1 with pericentric inversion, in the sperm nuclei of the carrier by using triple color fluorescence in situ hybridization (FISH). The centromere specific and telomere specific probes for chromosome 1 were used. In the segregation analysis, 1,636 sperm nuclei were analyzed; 82.5% of the sperms were including normal or inverted chromosome 1, and the dup(p)/del(q) and del(p)/dup(q) recombinant products in sperm nuclei of our carrier were 8.7 and 7.3%, respectively. The number of recombinant products may be dependent on the formation of an inversion loop, which the number of the formation of chiasmata results in the different number of normal/balanced and recombinant products. The use of FISH, using different probe combination, in sperm nuclei has proved to be an accurate approach to determine the meiotic segregation patterns and could help to better establish a reproductive prognosis and genetic counseling. (C) 2003 Wiley-Liss, Inc.
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    Meiotic segregation analysis of reciprocal translocations, both in sperms and blastomeres
    (WILEY-LISS, 2006) Yakut, Tahsin; Erçelen, Nesrin; Acar, Hasan; Kimya, Yalçın; Egeli, Ünal
    Balanced chromosomal rearrangements could lead to unbalanced segregation gametes during meiosis. In this Study, sperm flourescence ill situ hybridization (FISH) analysis of meiotic segregation products of four reciprocal translocations; 46,XY,t(7;10)(q21;q22), 46:XY,t(15;17)(q11;p12), 46,XY, t(6;13)(p21.1;q32), and 46,XY,t(1;13)(q24;q10) are presented. In three Out Of these four cases with t(15;17), t(6;13), and t(1;13) additional blastomere FISH analyses are also provided. multi-color FISH analysis was applied using diverse probe combinations specific for translocated chromosome segments. The average frequency of sperm nuclei bearing unbalanced products for t(7;10), t(15:17), t(6;13), and t(1;13) were 48.7%, 59.5%, 60.5%, and 62.9%, respectively. Frequencies of blastomeres comprising unbalanced products in Cases with t(15;17), t(6;13), and t(1:13) were 80% (12 of 15), 60% (3 of 5), and 50% (2 of 4), respectively. Chi-square test analysis showed significant differences in the meiotic segregation pattens Clue to the distribution and numbers of the chiasmatas that Could depend oil the size of the translocated segments (P < 0.001). In conclusion, FISH analysis of sperm and blastomere for reciprocal translocation carriers effectively estimates the approximate risk Of unbalanced products and this result might ensure Valuable genetic Counseling. (c) 2006 Wiley-Liss, Inc.