title: Changes in functional activities of plasma fibrinogen after treatment with methylene blue and red light.
abstract: BACKGROUND
  Methylene blue (MB) plus light treatment used for virus inactivation of human plasma units may lead to changes in the functional activities of fibrinogen.
  
  
  METHODS
  Single-donor units of fresh plasma were treated with 1.0 microM MB and a red light dose of 48 J per cm2. The effects of MB plus red light treatment on fibrinogen clottability, fibrin polymerization and gelation, clot stabilization, and fibrinolysis were studied.
  
  
  RESULTS
  The concentration of clottable fibrinogen was unchanged during MB plus red light treatment, but a light-dose-dependent decrease of the concentration of functional fibrinogen was found. The initial release rate of fibrinopeptide A was slightly increased after MB plus red light treatment. Turbidity measurements of fibrin gel showed prolonged clotting time, lower fibrin fiber mass-to-length ratio, and slightly smaller fiber diameter. At a given clotting time, a gel with lower fibrin fiber mass-to-length ratio was produced. Clot stability and fibrinolysis remained normal. l-Histidine added to plasma before MB plus red light treatment normalized the thrombin-induced coagulation time in a dose-dependent way.
  
  
  CONCLUSIONS
  MB plus red light treatment affected the polymerization and gelation phase of fibrin. A tighter fibrin gel structure was formed. No effect on stabilization of fibrin clot or fibrinolysis was found.
authors.affiliation: Department of Surgical Sciences/Blood Coagulation Research, Clinical Chemistry Building, Karolinska Hospital, SE-171 76 Stockholm, Sweden. Anna-Maija.Suontaka@ks.se
authors.forename: Anna-Maija
authors.initials: AM
authors.lastname: Suontaka
authors.forename: Margareta
authors.initials: M
authors.lastname: Blombäck
authors.forename: John
authors.initials: J
authors.lastname: Chapman
mesh_terms: D012103:Batroxobin / Q000494:pharmacology; D001769:Blood / Q000187:drug effects; D001777:Blood Coagulation; D005176:Factor XIII / Q000378:metabolism; D005337:Fibrin / Q000032:analysis; D005340:Fibrinogen / Q000032:analysis / Q000187:drug effects* / Q000502:physiology / Q000528:radiation effects*; D005342:Fibrinolysis; D005344:Fibrinopeptide A / Q000032:analysis; D005782:Gels; D006801:Humans; D008027:Light; D008751:Methylene Blue / Q000627:therapeutic use*; D009391:Nephelometry and Turbidimetry; D009994:Osmolar Concentration; D013917:Thrombin / Q000494:pharmacology; D038301:Virus Inactivation; D014914:Whole Blood Coagulation Time
chemical_list: D005782:Gels; D005344:Fibrinopeptide A; D005337:Fibrin; D005340:Fibrinogen; D005176:Factor XIII; D012103:Batroxobin; D013917:Thrombin; D008751:Methylene Blue