Ken Okamoto

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Uridine-diphosphate glucuronosyltransferase 1A (UGT1A) is a key enzyme involved in irinotecan metabolism, and polymorphisms in the UGT1A gene are associated with irinotecan-induced toxicity. The aim of this study was to elucidate the allele frequencies of UGT1A polymorphisms in healthy Uzbek volunteers, and to compare them with those of the Japanese(More)
Xanthine oxidoreductase (XOR), which is widely distributed from humans to bacteria, has a key role in purine catabolism, catalyzing two steps of sequential hydroxylation from hypoxanthine to xanthine and from xanthine to urate at its molybdenum cofactor (Moco). Human XOR is considered to be a target of drugs not only for therapy of hyperuricemia and gout,(More)
(±)-Tramadol hydrochloride (tramadol) is a widely used analgesic for the treatment of cancer pain and chronic pain. Although many animal studies have shown antinociceptive effects of tramadol in both acute and chronic pain, little is known about the effect of tramadol in putative animal models of fibromyalgia. In this study, we compared the antiallodynic(More)
Xanthine oxidoreductase (XOR), a complex flavoprotein, catalyzes the metabolic reactions leading from hypoxanthine to xanthine and from xanthine to urate, and both reactions take place at the molybdenum cofactor. The enzyme is a target of drugs for therapy of gout or hyperuricemia. We review the chemical nature and reaction mechanisms of the molybdenum(More)
Febuxostat, a drug recently approved in the US, European Union and Japan for treatment of gout, inhibits xanthine oxidoreductase (XOR)-mediated generation of uric acid during purine catabolism. It inhibits bovine milk XOR with a K(i) in the picomolar-order, but we found that it is a much weaker inhibitor of Rhodobacter capsulatus XOR, even though the(More)
Xanthine oxidoreductase (XOR) catalyzes the conversion of hypoxanthine to xanthine and xanthine to uric acid with concomitant reduction of either NAD+ or O(2). The enzyme is a target of drugs to treat hyperuricemia, gout and reactive oxygen-related diseases. Human diseases associated with genetically determined dysfunction of XOR are termed xanthinuria,(More)
Global cerebral ischemia and reperfusion (I/R) often result in high mortality. Free radicals play an important role in global cerebral I/R. Xanthine oxidoreductase (XOR) inhibitors, such as allopurinol, have been reported to protect tissues from damage caused by reactive oxygen species (ROS) by inhibiting its production through XOR inhibition. The recently(More)
AIM To determine the distance between the branching point of the left colic artery (LCA) and the inferior mesenteric artery (IMA) by computed tomography (CT) scanning, for preoperative evaluation before laparoscopic colorectal operation. METHODS From February 2004 to May 2005, 100 patients (63 men, 37 women) underwent angiography performed with a(More)
Novel longer lasting inflammatory bladder animal models are needed to better understand the pathophysiology of chronic cystitis. We previously developed a relatively long-lasting mouse cystitis model by intravesical injection of hydrogen peroxide (H2O2). To further evaluate its pathophysiology, in this study, we established and analyzed a rat cystitis(More)
BACKGROUND Aortic valve surgery in patients with severely calcified aortas is technically challenging. Additionally, the choice of arterial cannulation site and whether to perform an aortic clamp to prevent neurological complications are poorly defined. CASE PRESENTATION We describe a patient with a severely calcified aorta and stenosis of its side(More)