title: Age-related changes in cellular activity in human submandibular glands as evaluated by argyrophilic nucleolar organizer regions.
abstract: OBJECTIVE
  To examine the age-related changes in cellular activity of epithelial components of human submandibular glands, evaluated on the basis of argyrophilic nucleolar organizer regions (AgNORs).
  
  
  METHODS
  Epithelial components of human submandibular glands were divided into serous acinar cells, mucous acinar cells, intercalated duct cells, striated duct cells, and interlobular duct cells. The mean AgNOR number of each cell type was compared among six age groups.
  
  
  METHODS
  The study was conducted at the Department of Oral Pathology, Tohoku University School of Dentistry, Japan.
  
  
  METHODS
  Necropsy specimens from 66 males and 57 females 1 to 97 years old.
  
  
  RESULTS
  In all cell types except for intercalated duct cells, the mean AgNOR number was lowest in the 0-14 year-old group and highest in the 15-29 year-old group. The value then gradually decreased with advancing age and ultimately reached a similar level to that in the 0-14 year-old group. In intercalated duct cells, the mean AgNOR number did not differ significantly between any age group. There were no significant sex-related differences.
  
  
  CONCLUSIONS
  The cellular activity of almost all components of human submandibular glands rises in adolescence and young adulthood and then decreases with aging. These results suggest that intercalated duct cells are capable of not only proliferation but also division into other components; these cells may thus compensate for the reduced activity of other components in elderly subjects.
authors.affiliation: Department of Oral Pathology, Tohoku University School of Dentistry, Sendai, Japan. shizu-hp@pc4.so-net.ne.jp
authors.forename: M
authors.initials: M
authors.lastname: Saito
authors.forename: Y
authors.initials: Y
authors.lastname: Shimizu
mesh_terms: D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000502:physiology*; D000704:Analysis of Variance; D002648:Child; D002675:Child, Preschool; D004847:Epithelial Cells / Q000502:physiology; D005260:Female; D006801:Humans; D007223:Infant; D016014:Linear Models; D008297:Male; D008875:Middle Aged; D009697:Nucleolus Organizer Region / Q000502:physiology*; D012737:Sex Factors; D016622:Silver Staining; D013363:Submandibular Gland / Q000166:cytology* / Q000502:physiology*