title: Circadian pattern and the effect of standardized physical exercise on procollagen IIA N-peptide (PIIANP) in rheumatoid arthritis at different stages and in healthy individuals.
abstract: BACKGROUND
  Variant collagen IIA is re-expressed in diseased cartilage. Low procollagen IIA N-peptide (PIIANP) levels in serum have recently been reported in rheumatoid arthritis (RA). We investigated circadian rhythmicity and effect of physical activity on PIIANP in early and longstanding RA and in healthy subjects.
  
  
  METHODS
  Patients with early and longstanding RA and controls were included. Fasting and serial blood samples were collected during 24 h. PIIANP response to physical activity was studied before and serially after standardized exercise.
  
  
  CONCLUSIONS
  In RA at different stages and healthy individuals, PIIANP exhibited no circadian rhythmicity, and PIIANP in serum was not influenced by physical activity.
authors.affiliation: Department of Rheumatology, Odense University Hospital, Odense, Denmark. a.friesgaard@gmail.com
authors.forename: Anne Friesgaard
authors.initials: AF
authors.lastname: Christensen
authors.forename: T
authors.initials: T
authors.lastname: Lottenburger
authors.forename: H M
authors.initials: HM
authors.lastname: Lindegaard
authors.forename: K
authors.initials: K
authors.lastname: Junker
authors.forename: K
authors.initials: K
authors.lastname: Hørslev-Petersen
authors.forename: P
authors.initials: P
authors.lastname: Junker
mesh_terms: D000328:Adult; D000368:Aged; D001172:Arthritis, Rheumatoid; D016022:Case-Control Studies; D002940:Circadian Rhythm; D024043:Collagen Type II / Q000097:blood*; D015444:Exercise; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged
chemical_list: D024043:Collagen Type II