title: Evaluation of the nucleolar organizer regions in Alzheimer's disease.
abstract: BACKGROUND
  Alzheimer's disease (AD) is a neurodegenerative disorder in middle and late age. Ribosomal RNA (rRNA) genes are located in the nucleolus (nucleolar organizer regions = NORs). There are increased deposits of beta-amyloid protein in the brains of the patients with AD and aged individuals with Down's syndrome (DS). The beta-amyloid gene is located in the acrocentric chromosome 21 that is responsible for rRNA synthesis. Therefore, it is possible that there is a relationship between ribosomal genes and AD.
  
  
  OBJECTIVE
  To investigate the activities of ribosomal genes of AD patients by comparing the activities of NORs in AD patients and healthy controls with the silver-staining method.
  
  
  METHODS
  NOR surface/the total nucleus surface proportions in interphase nuclei, and silver stainability and satellite association (SA) of acrocentric chromosomes in the metaphases of cultivated lymphocytes of 20 AD patients and 20 healthy controls (10 elderly and 10 young) were evaluated.
  
  
  RESULTS
  A decrease in NOR surface/total nucleus surface proportions has been observed in the interphase nucleus of AD patients when compared with elderly controls (p = 0.035). When compared with the sizes of Ag+ segments of acrocentric chromosomes of AD patients and control groups, the Ag-staining size 1 of the chromosome 22 of AD patients was found to be more increased than that of the young controls (p = 0.018). There was no statistically significant difference between AD patients and control groups regarding the number of Ag+ acrocentric chromosomes, Ag+ chromosome 21 and SA frequency (p > 0.05). It has been found that there is only a slight increase in the total number of chromosomes in SA in AD patients when compared with elderly controls (p = 0.05).
  
  
  CONCLUSIONS
  The decrease in NOR surface/total nucleus surface proportions of AD patients may indicate a reduction in the activity of the ribosomal genes of these patients.
authors.affiliation: Department of Medical Biology, Erciyes University Medical Faculty, Kayseri, Turkey. donmezh@erciyes.edu.tr
authors.forename: Hamiyet
authors.initials: H
authors.lastname: Dönmez-Altuntaş
authors.forename: Hilal
authors.initials: H
authors.lastname: Akalin
authors.forename: Yahya
authors.initials: Y
authors.lastname: Karaman
authors.forename: Halil
authors.initials: H
authors.lastname: Demirtaş
authors.forename: Nalan
authors.initials: N
authors.lastname: Imamoğlu
authors.forename: Yusuf
authors.initials: Y
authors.lastname: Ozkul
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000473:pathology; D000544:Alzheimer Disease / Q000235:genetics* / Q000473:pathology*; D002877:Chromosomes, Human; D005260:Female; D006801:Humans; D007399:Interphase; D008297:Male; D008875:Middle Aged; D009697:Nucleolus Organizer Region / Q000473:pathology* / Q000502:physiology*; D012335:RNA, Ribosomal / Q000502:physiology; D016622:Silver Staining
chemical_list: D012335:RNA, Ribosomal