Condensed chromatin surface and NORs surface enhancement in mitogen-stimulated lymphocytes of Down syndrome patients.
Mitogen-stimulated lymphocytes of 20 Down syndrome (DS) patients with regular trisomy 21 contain more condensed chromatin surface (11.28 +/- 2.64 % of the total nuclear surface: mean +/- SD) and more nucleolus organiser regions surface (13.21 +/- 3.45 %) than that of 12 healthy controls: (8.84 +/- 2.23 and 9.12 +/- 2.33 %, reciprocally). The source of this peculiarity has been investigated. A computer program was designed for the planimetric measurement of the condensed chromatin surface (CCs)/ total nuclear surface(TNs) and the nucleolus organiser regions surface (NORss) /TNs proportions in interphase nuclei. CCs/TNs and NORss/TNs of 100 maximally activated nuclei (MANs) were measured for each patient and control case. The difference was found highly significant (P<0.01). Nuclei with a diameter of >/= 17 micrometer measured on the slide (in flattened state) were considered as maximally activated nuclei (MANs). NORss/TNs enhancement and fluorescent in situ hybridisation (FISH) studies in MANs of DS patients indicate that this phenomenon is due to the over-expression (or lack of downregulative mechanism) of NORs (rDNA) to some extent, including the NOR of the supernumerary chromosome 21. No statistical difference was observed between 12 healthy controls and 5 Robertsonian translocation type of DS Patients (where the two involved NORs are missing) when the two parameters were considered.
Demirtas
H
H
Med. Biol. and Genetics Dept., Medical Faculty, Erciyes University, 38039, Kayseri, Turkey
Imamoglu
N
N
Dönmez
H
H
Cücer
N
N
Yilmaz
A
A
Candemir
Z
Z
D016022:Case-Control Studies; D002467:Cell Nucleus / Q000187:drug effects / Q000378:metabolism / Q000473:pathology; D002478:Cells, Cultured; D002843:Chromatin / Q000235:genetics / Q000378:metabolism / Q000473:pathology*; D004314:Down Syndrome / Q000235:genetics* / Q000473:pathology*; D006801:Humans; D017404:In Situ Hybridization, Fluorescence; D008214:Lymphocytes / Q000187:drug effects* / Q000378:metabolism / Q000473:pathology; D008934:Mitogens / Q000494:pharmacology*; D009697:Nucleolus Organizer Region / Q000235:genetics / Q000378:metabolism / Q000473:pathology*; D016622:Silver Staining
D002843:Chromatin; D008934:Mitogens