The transport kinetics of [99mTc]-pyridoxyl-5-methyltryptophan were studied by three-compartment model analysis for hepatobiliary scintigraphy in 45 patients with chronic viral liver diseases. Three-compartment model analysis was studied using the time-activity curves of the regions of the heart, liver, and biliary tract and intestine (excretory compartment). The k12 (hepatic uptake rate constant), k21 (hepatic efflux rate constant), and ke1 (hepatic excretion rate constant) were calculated by the nonlinear least-squares method. Among the three parameters obtained by model analysis, k12 values more prominently differed among diseases and correlated well with blood tests such as total bilirubin, total bile acids, or 15 min retention of ICG. In conclusion, three-compartment model analysis of the hepatic handling of [99mTc]-pyridoxyl-5-methyltryptophan is useful in evaluating hepatic transport function. k12 is the most sensitive parameter for this.

Biliary Tract↗

PubMedDate not supplied

Intestinal absorption of lithocholate and its sulfate and glucuronide in rats.

The absorption of lithocholate and its sulfate and glucuronide in rat jejunum and terminal ileum was studied. Tracer amounts of radiolabelled bile acids were administered to the ligated intestinal segments, and their absorption was monitored by biliary excretion through a bile duct catheter. Absorption of lithocholate was faster in the terminal ileum than in the jejunum. Although the sulfation reduced lithocholate absorption in the jejunum, it did not affect lithocholate absorption in the terminal ileum. This was due to the Na+-dependency of ileal absorption of lithocholate-sulfate assessed by perfusion studies. In contrast, the glucuronidation markedly reduced lithocholate absorption both in the jejunum and the terminal ileum. These findings indicate that the glucuronidation is more effective than sulfation in detoxifying lithocholate as far as the prevention of its intestinal absorption is concerned.

Absorption↗

PubMedDate not supplied

Targeting immunotherapy using the avidin-biotin system for a human colon adenocarcinoma in vitro.

A new method of targeting immunotherapy using the avidin-biotin system in vitro was investigated. Both an anti-carcinoembryonic antigen monoclonal antibody (anti-CEA MAb) and an anti-cancer drug, neocarzinostatin (NCS), were biotinylated. A human colon adenocarcinoma cell line (LoVo) was immunized with biotinylated anti-CEA MAb; avidin was added, and the cell line was incubated with various concentrations of biotinylated NCS for either 72 h or 7 min. In the incubation for 72 h, the IC50 was similar (approximately 0.45 microgram/ml) for biotinylated NCS for LoVo cells immunized with biotinylated anti-CEA MAb and those without immunization. In the incubation for 7 min, the IC50 (concentration producing 50% cytotoxicity) of biotinylated NCS for LoVo cells immunized with biotinylated anti-CEA MAb (0.35 microgram/ml) was five times less than that of non-immunized LoVo cells (1.8 micrograms/ml). Thus the present system has the potential to reduce the dosage of anti-cancer drugs needed, and this strategy seems likely to be a valuable clinical tool in targeting immunotherapy.

Adenocarcinoma↗