title: Effects of combined oral administration and intravenous injection on maintaining decreased systemic tyrosine levels in rats.
abstract: Our previous studies have indicated that encapsulated tyrosinase and crosslinked hemoglobin with tyrosinase (polyhemoglobin-tyrosinase) decrease systemic tyrosine level significantly in rats. However, we need a few days of oral administration of encapsulated tyrosinase before the systemic tyrosine level starts to decrease. Although intravenous injection of polyhemoglobin tyrosinase can lower the systemic tyrosine to about 10% within an hour, the level increases towards normal after 24 h. We therefore investigate the effects of intravenous injection of polyhemoglobin-tyrosinase combined with oral administration of encapsulated tyrosinase on lowering the systemic tyrosine level. In addition, we further optimize this combined method for lowering systemic tyrosine in animal studies and have found out that two intravenous injections of polyhemoglobin-tyrosinase followed by three times a day oral administration of encapsulated tyrosinase could immediately lower the body tyrosine and maintain this low level as long as the oral administration is continued.
authors.affiliation: Artificial Cells and Organs Research Center and MSSS-FRSQ Research Group (d'equipe) on Blood Substitutes in Transfusion Medicine, Faculty of Medicine, McGill University, Montreal, Quebec, Canada.
authors.forename: Binglan
authors.initials: B
authors.lastname: Yu
authors.forename: Thomas Ming Swi
authors.initials: TM
authors.lastname: Chang
mesh_terms: D000284:Administration, Oral; D000818:Animals; D002214:Capsules; D006454:Hemoglobins / Q000627:therapeutic use; D007275:Injections, Intravenous; D008297:Male; D008545:Melanoma / Q000188:drug therapy; D014442:Monophenol Monooxygenase / Q000008:administration & dosage*; D010100:Oxygen / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D014443:Tyrosine / Q000097:blood / Q000187:drug effects*
chemical_list: D002214:Capsules; D006454:Hemoglobins; C037158:polyhemoglobin; D014443:Tyrosine; D014442:Monophenol Monooxygenase; D010100:Oxygen