title: Ornithine breath test as a method to evaluate functional liver volume.
abstract: BACKGROUND
  The purpose of this study was to investigate whether the functional liver volume can be measured from changes in expiratory 13CO2 levels after intravenous administration of L-[1, 2-13C] ornithine, using a rat model of hepatectomy.
  
  
  METHODS
  Under pentobarbital anesthesia, 30%, 70%, or 90% hepatectomy was performed. In the control group, simple laparotomy was performed. Then, 20 mg/kg L-[1, 2-13C] ornithine was administered to rats via the femoral vein. A breath test was conducted 20 min after laparotomy. We examined the correlation of the sum of 13CO2 output (S) or a single point of 13CO2 level (SP) with liver weight/body weight (LW/BW) (%) every 15 min.
  
  
  RESULTS
  In all of the groups, the ornithine breath test (OBT) graph reached a plateau level at about 6 min. The correlation coefficient between S15 and LW/BW was highest 0.952 (P <0.0001). The correlation coefficient between SP14 and LW/BW was highest, 0.944 (P <0.0001). The severity of hepatic injury could be evaluated, with significant differences in S5-15 and SP5-15 in all comparisons between groups.
  
  
  CONCLUSIONS
  In the breath test with intravenously administered L-[1, 2-13C] ornithine, functional liver volume could be evaluated accurately in a short period.
authors.affiliation: Department of Surgery, Division 3, Nihon University School of Medicine, Tokyo, Japan.
authors.forename: Masaru
authors.initials: M
authors.lastname: Aoki
authors.forename: Yukimoto
authors.initials: Y
authors.lastname: Ishii
authors.forename: Satoshi
authors.initials: S
authors.lastname: Asai
authors.forename: Koichi
authors.initials: K
authors.lastname: Ishikawa
authors.forename: Tadatoshi
authors.initials: T
authors.lastname: Takayama
mesh_terms: D000818:Animals; D001944:Breath Tests; D006498:Hepatectomy; D008099:Liver / Q000502:physiology*; D008111:Liver Function Tests; D008115:Liver Regeneration / Q000502:physiology*; D008297:Male; D023421:Models, Animal; D009929:Organ Size / Q000502:physiology; D009952:Ornithine / Q000032:analysis*; D051381:Rats; D017208:Rats, Wistar
chemical_list: D009952:Ornithine