Publications

Based on in vitro rat and human hepatocyte uptake studies showing inhibition of warfarin uptake in the presence of the nonspecific organic anion-transporting polypeptide (OATP) inhibitor rifampin, a clinical study was conducted in 10 healthy volunteers to examine the in vivo relevance of OATP hepatic uptake on the pharmacokinetics of warfarin. In a randomized, single-dose, two-period, crossover design, subjects received a 7.5-mg dose of warfarin, either alone or immediately following a 600-mg intravenous dose of rifampin. Rifampin did not significantly alter the R- or S-warfarin area under the concentration-time curves (AUCs) from 0 to 12 h (period of hepatic OATP inhibition by rifampin) or the maximum plasma concentration (C(max)) value. AUC(0-∞) was decreased on days rifampin was administered, for both R-warfarin (25% reduction; P < 0.001) and S-warfarin (15% reduction; P < 0.05). No differences were seen in the area under the international normalized ratio (INR)-time curve. Our study suggests that hepatic uptake via OATPs may not be clinically important in the pharmacokinetics of warfarin.

Curative endoscopic resection is now a viable option for a range of neoplastic lesions of the gastrointestinal tract (GIT) with low invasive potential. Risk of lymph node metastasis is the most important prognostic factor in selecting appropriate lesions for endoscopic therapy, and assessment of invasion depth is vital in this respect. To determine appropriate treatment, detailed endoscopic diagnosis and estimation of depth using magnifying chromoendoscopy is the gold standard in Japan. En bloc resection is the most desirable endoscopic therapy as risk of local recurrence is low and accurate histological diagnosis of invasion depth is possible. Endoscopic mucosal resection is established worldwide for the ablation of early neoplasms, but en bloc removal using this technique is limited to small lesions. Evidence suggests that a piecemeal resection technique has a higher local recurrence risk, therefore necessitating repeated surveillance endoscopy and further therapy. More advanced endoscopic techniques developed in Japan allow effective en bloc removal of early GIT neoplasms, regardless of size. This review discusses assessment of GIT lesions and options for endoscopic therapy with special reference to the introduction of endoscopic submucosal dissection into Western countries.