Keiichi Kawai

Bio: Keiichi Kawai is an academic researcher from RMIT University. The author has contributed to research in topics: Organic anion transporter 1 & Human serum albumin. The author has an hindex of 35, co-authored 261 publications receiving 3791 citations. Previous affiliations of Keiichi Kawai include University of Fukui & University of Texas MD Anderson Cancer Center.

消化器内科外来におけるhospital anxiety and depression scale(HAD尺度)日本語版の信頼性と妥当性の検討

Abstract: This study examined the validity of the Japanese version of the hospital anxiety and depression scale (HAD) in a gastro-intestinal outpatient clinic. One hundred and twenty-three men and 142 women consulting a gastro-intestinal outpatient clinic at a primary care hospital in Kyoto during 1995 were surveyed. Item-remainder correlation and internal consistency were examined for reliability. Concurrent validities were examined using the stait-trait anxiety inventory (STAI) and Zung's self-rating depression scale (SDS). The prevalence of psychiatric disorder in this population ranged from 27% to 39%. Cronbach's coefficients were greater than 0.8 for the anxiety subscale and more than 0.7 for the depression subscale. Spearman's correlation of the anxiety subscale scores and the STAI were r = 0.678 for men, and r = 0.717 for women. The correlation of depression subscale scores and SDS were r = 0.457 for men, and r = 0.565 for women. It is suggested that the use of the HAD to general hospital outpatients clinic would facilitate detecting emotional disorders in outpatients.

Staging of pancreatic carcinoma by endoscopic ultrasonography.

Abstract: The ability of EUS to diagnose small pancreatic cancer is well known. In this study, we present our experience with EUS in the local staging of 29 patients with pancreatic carcinoma who underwent surgery. EUS was 79, 83 and 79% accurate in determining anterior (including gastric), duodenal and retroperitoneal (vascular) invasion by the tumor. Ultrasonography (48, 39 and 55%, respectively) and CT (38, 33 and 41%, respectively) were less reliable. EUS was equal to angiography in diagnosing vascular involvement. EUS was more effective in detecting splenoportal infiltration (sensitivity 88%, specificity 78%) than arterial involvement (accuracy 50%). EUS was also less reliable in determining the N stage (66%) and in stage grouping (72%). Although EUS is superior to ultrasonography and CT in the local staging of pancreatic carcinoma, further studies must show whether improved staging criteria will lead to better results.

Putative Transport Mechanism and Intracellular Fate of Trans-1-Amino-3-18F-Fluorocyclobutanecarboxylic Acid in Human Prostate Cancer

Abstract: Trans-1-amino-3- 18 F-fluorocyclobutanecarboxylic acid (anti– 18 FFACBC) is an amino acid PET tracer that has shown promise for visualizing prostate cancer. Therefore, we aimed to clarify the anti– 18 F-FACBC transport mechanism in prostate cancer cells. We also studied the fate of anti– 18 F-FACBC after it is transported into cells. Methods: For convenience, because of their longer half-lives, 14C compounds were used instead of 18 F-labeled tracers. Trans-1-amino-3-fluoro-1- 14 C-cyclobutanecarboxylic acid (14C-FACBC) uptake was examined in human prostate cancer DU145 cells with the following substrates of amino acid transporters: a-(methylamino) isobutyric acid (a system A–specific substrate) and 2-amino-2-norbornanecarboxylic acid (a system L–specific substrate). The messenger RNA expression of amino acid transporters in human prostate cancer specimens was analyzed by complementary DNA microarray and quantitative real-time reverse transcription polymerase chain reaction (qRT-PCR). Gene expression in DU145 cells was analyzed by qRT-PCR. We also examined the knockdown effect of the amino acid transporters system ASC transporter 2 (ASCT2) and sodium-coupled neutral amino acid transporter 2 (SNAT2) on 14 C-FACBC uptake. In addition, the possibility of 14C-FACBC incorporation into proteins was examined. Results: 14 C-FACBC uptake by DU145 cells was markedly decreased to approximately 20% in the absence of Na1, compared with that in its presence, indicating that Na 1 -dependent transporters are mainly responsible for the uptake of this tracer. Moreover, 2-amino-2-norbornanecarboxylic acid inhibited the transport of 14 C-FACBC to the basal level in Na 1 -free buffer. In contrast, a-(methylamino) isobutyric acid did not inhibit 14 C-FACBC accumulation in DU145 cells. Human prostate tumor specimens and DU145 cells had similar messenger RNA expression patterns of amino acid transporter genes. Although SNAT2 and ASCT2 are 2 major amino acid transporters expressed in prostate tumor tissues and DU145 cells, ASCT2 knockdown using small interfering RNA was more effective in lowering 14C-FACBC transport than SNAT2. Almost all intracellular 14 C-FACBC was recovered from the nonprotein fraction. Conclusion: ASCT2, which is a Na1-dependent amino acid transporter, and to a lesser extent Na 1 -independent transporters play a role in the uptake of 14 C-FACBC by DU145 cells. Among the Na 1 -independent transporters, system L transporters are also involved in the transport of 14 C-FACBC. Moreover, 14 C-FACBC is not incorporated into proteins in cells. These findings suggest a possible mechanism of anti– 18 F-FACBC

Inhibitory effect of quercetin on the synthesis of a possibly cell-cycle-related 17-kDa protein, in human colon cancer cells

Abstract: Quercetin inhibits growth of COLO320 DM cells, derived from a human colon cancer. The inhibitory effect is partially reversible when quercetin is removed from the culture medium. Flow cytometric analysis has revealed that quercetin causes perturbation of the cell cycle, inducing a frozen cell-cycle pattern and a block at the G1/S boundary. The synthesis of a 17-kDa protein was specifically inhibited by the addition of quercetin, and recovered when the cells at the G1/S boundary progressed into S-phase after the removal of quercetin from the culture medium. Furthermore, using synchronized cells obtained by centrifugal elutriation, we have shown that the rate of synthesis of a 17-kDa protein was low in G1, and high in S-phase of the cell cycle. Thus, this protein appears to be cell-cycle-related.

The Effects of Plant Flavonoids on Mammalian Cells:Implications for Inflammation, Heart Disease, and Cancer

Abstract: Flavonoids are nearly ubiquitous in plants and are recognized as the pigments responsible for the colors of leaves, especially in autumn. They are rich in seeds, citrus fruits, olive oil, tea, and red wine. They are low molecular weight compounds composed of a three-ring structure with various substitutions. This basic structure is shared by tocopherols (vitamin E). Flavonoids can be subdivided according to the presence of an oxy group at position 4, a double bond between carbon atoms 2 and 3, or a hydroxyl group in position 3 of the C (middle) ring. These characteristics appear to also be required for best activity, especially antioxidant and antiproliferative, in the systems studied. The particular hydroxylation pattern of the B ring of the flavonoles increases their activities, especially in inhibition of mast cell secretion. Certain plants and spices containing flavonoids have been used for thousands of years in traditional Eastern medicine. In spite of the voluminous literature available, however, Western medicine has not yet used flavonoids therapeutically, even though their safety record is exceptional. Suggestions are made where such possibilities may be worth pursuing.

Intake of potentially anticarcinogenic flavonoids and their determinants in adults in the Netherlands

Abstract: Flavonoids are strong antioxidants that occur naturally in foods and can inhibit carcinogenesis in rodents. Accurate data on population-wide intakes of flavonoids are not available. Here, using data of the Dutch National Food Consumption Survey 1987-1988, we report the intake of the potentially anticarcinogenic flavonoids quercetin, kaempferol, myricetin, apigenin, and luteolin among 4,112 adults. The flavonoid content of vegetables, fruits, and beverages was determined by high-performance liquid chromatography. In all subjects, average intake of all flavonoids combined was 23 mg/day. The most important flavonoid was the flavonol quercetin (mean intake 16 mg/day). The most important sources of flavonoids were tea (48% of total intake), onions (29%), and apples (7%). Flavonoid intake did not vary between seasons; it was not correlated with total energy intake (r = 0.001), and it was only weakly correlated with the intake of vitamin A (retinol equivalents, r = 0.14), dietary fiber (r = 0.21), and vitamin C (r = 0.26). Our use of new analytic technology suggests that in the past flavonoid intake has been overestimated fivefold. However, on a milligram-per-day basis, the intake of the antioxidant flavonoids still exceeded that of the antioxidants beta-carotene and vitamin E. Thus flavonoids represent an important source of antioxidants in the human diet.