title: Seasonal variation and stability of matrix metalloproteinase-9 activity and tissue inhibitor of matrix metalloproteinase-1 with storage at -80°C.
abstract: OBJECTIVE
  To determine whether active matrix metalloproteinase (MMP)-9 and tissue inhibitor of matrix metalloproteinase (TIMP)-1 displayed seasonal variation and were stable in storage.
  
  
  METHODS
  Plasma active MMP-9 and TIMP-1 were measured at three time-points in 163 individuals.
  
  
  RESULTS
  There was no evidence for seasonal variation or declining levels for up to three years of storage at -80°C.
  
  
  CONCLUSIONS
  Active MMP-9 and TIMP-1 appear to be stable seasonally, and in storage for at least three years.
authors.affiliation: Department of Surgical Sciences, University of Otago, Dunedin, New Zealand.
authors.forename: G P
authors.initials: GP
authors.lastname: Tarr
authors.forename: M J A
authors.initials: MJ
authors.lastname: Williams
authors.forename: L V
authors.initials: LV
authors.lastname: Phillips
authors.forename: A M
authors.initials: AM
authors.lastname: van Rij
authors.forename: G T
authors.initials: GT
authors.lastname: Jones
mesh_terms: D015415:Biomarkers / Q000097:blood; D001793:Blood Preservation; D004795:Enzyme Stability; D005260:Female; D006801:Humans; D008297:Male; D020780:Matrix Metalloproteinase 9 / Q000097:blood*; D008875:Middle Aged; D010949:Plasma / Q000737:chemistry* / Q000201:enzymology*; D012621:Seasons; D013048:Specimen Handling; D013995:Time; D019715:Tissue Inhibitor of Metalloproteinase-1 / Q000097:blood*
chemical_list: D015415:Biomarkers; D019715:Tissue Inhibitor of Metalloproteinase-1; D020780:Matrix Metalloproteinase 9