Inhibitory mechanisms of flavonoids on insulin-stimulated glucose uptake in MC3T3-G2/PA6 adipose cells.

We assessed the effects of different classes of flavonoids on insulin-stimulated 2-deoxy-D-[1-(3)H]glucose uptake by mouse MC3T3-G2/PA6 cells differentiated into mature adipose cells. Among the flavonoids examined, the flavones, apigenin and luteolin, the flavonols, kaempferol, quercetin and fisetin, an isoflavone, genistein, a flavanonol, silybin, and the flavanols, (-)-epigallocatechin gallate (EGCG) and theaflavins, significantly inhibited insulin-stimulated glucose uptake. Key structural features of flavonoids for inhibition of insulin-stimulated glucose uptake are the B-ring 4'- or 3',4'-OH group and the C-ring C2-C3 double bond of the flavones and flavonols, the A-ring 5-OH of isoflavones, and the galloyl group of EGCG and theaflavins. Luteolin significantly inhibits insulin-stimulated phosphorylation of insulin receptor-beta subunit (IR-beta), and apigenin, kaempferol, quercetin and fisetin, also tended to inhibit the IR-beta phosphorylation. On the other hand, isoflavones, flavanols or flavanonols did not affect insulin-stimulated IR-beta phosphorylation. Apigenin, luteolin, kaempferol, quercetin and fisetin also appeared to inhibit insulin-stimulated activation of Akt, a pivotal downstream effector of phosphatidylinositol 3-kinase (PI3K), and suppressed insulin-dependent translocation of a glucose transporter, (GLUT)4, into the plasma membrane. Although genistein, silybin, EGCG and theaflavins had no effect on the insulin-stimulated activation of Akt, they blocked insulin-dependent GLUT4 translocation. These results provide novel insights into the modulation by flavonoids of insulin's actions, including glucose uptake in adipocytes.

Involvement of ABC transporters in chemosensitivity of human renal cell carcinoma, and regulation of MRP2 expression by conjugated bilirubin.

In this study, the involvement of ATP-binding cassette (ABC) transporters in in vitro chemosensitivity of surgically removed human renal cell carcinomas was investigated. The relative expression levels of transporter mRNAs in the renal tumors from 13 patients were similar to those in the surrounding normal kidney tissues. Five renal cell carcinomas cultured successfully in vitro for 14 days showed significantly decreased expression of multi-drug resistance-associated proteins 2 and 6 (MRP2 and MRP6) mRNAs. In vitro chemosensitivity testing of the same specimens using the collagen-gel matrix assay indicated that some anticancer drugs were effective, especially cisplatin, which is an MRP2 substrate. MRP2 mRNA expression in renal carcinoma was significantly increased when cells were cultured in the presence of conjugated bilirubin. In an established renal proximal tubule epithelial cell line (RPTEC), conjugated bilirubin increased MRP2 expression at the mRNA and protein levels, and decreased the cisplatin sensitivity of the cells. These results indicate that MRP2 expression in renal cell carcinoma may be regulated by conjugated bilirubin in the body and decreased during in vitro culture. Thus, the effectiveness of anticancer drugs selected on the basis of in vitro chemosensitivity testing of clinical cancers may be overestimated.

Inhibitory mechanism of caffeine on insulin-stimulated glucose uptake in adipose cells.

Caffeine inhibits insulin-induced glucose uptake in rat adipocytes and also decreases insulin sensitivity, including whole-body glucose disposal and glucose uptake in skeletal muscle, during a euglycemic-hyperinsulinemic clamp in human. However, the mechanism by which caffeine decreases the insulin sensitivity is not still clear. We found that pre-treatment with caffeine inhibited the insulin-induced 2-deoxy-D-[1-(3)H]glucose uptake in a concentration-dependent manner in mouse preadipose MC-3T3-G2/PA6 cells differentiated into mature adipose cells. Caffeine also suppressed insulin-induced GLUT4 translocation in the differentiated cells. Although caffeine did not alter insulin-induced activation of PI3K and protein kinase C-zeta (PKCzeta), an isoform of atypical PKC, which is reported to have an important role in insulin-induced GLUT4 translocation, we found that insulin-induced phosphorylation and activation of Akt were blocked by pre-treatment with caffeine. Inhibition of insulin-induced 2-deoxy-D-[1-(3)H]glucose uptake by caffeine was also observed in primary cultured brown adipocytes in a concentration-dependent manner. These results may, in part, explain the ability of caffeine to decrease insulin sensitivity.

A randomized, double-blind, placebo-controlled clinical trial of the Chinese herbal medicine "ba wei di huang wan" in the treatment of dementia.

OBJECTIVES: To evaluate whether a traditional Chinese herbal medicine, ba wei di huang wan (BDW), improves cognitive and physical functioning in dementia patients. DESIGN: An 8-week randomized, double-blind, placebo-controlled trial. SETTING: Long-term-care facility in Japan. PARTICIPANTS: Thirty-three patients with mild to severe dementia (7 men and 26 women; mean age +/- standard deviation=84.4 +/- 7.8) were recruited and enrolled from May 2002 through September 2002. INTERVENTION: Participants were randomly assigned to the active drug (BDW) group (n=16) or the placebo group (n=17) and treated for 8 weeks. MEASUREMENT: Cognitive function and activities of daily living (ADLs); palsatility index. RESULTS: After the trial, cognitive function as assessed using the Mini-Mental State Examination (MMSE) significantly improved from 13.5 +/- 8.5 to 16.3 +/- 7.7 (P<.01, 95% confidence interval (CI)=-4.1 to -1.4) in the BDW group. The ADL score in the Barthel Index also significantly changed, from 61.8 +/- 34.6 to 78.9 +/- 21.1 (P<.01, 95% CI=-26.2 to -7.9). In contrast, MMSE and Barthel Index scores of the placebo group showed no significant change. Eight weeks after the end of the administration, MMSE and Barthel Index scores of the BDW group declined to the baseline level. The pulsatility index in the internal carotid artery as measured using Doppler sonography significantly decreased in the BDW group (2.5 +/- 1.7 to 1.9 +/- 0.5, P<.05) but not in the placebo group. CONCLUSION: These results argue the benefits of BDW in the treatment of dementia.

[Electronic links between hospitals or clinics and pharmacies: structure and operation of WAKASHIO pharmacotherapeusis network].

We developed the WAKASHIO Pharmacotherapeusis Network system. This system electronically links physicians' offices with pharmacies to share clinical records and offers the means for real time bi-directional information input. The system is equipped with individual signature (handwriting) recognition protocols to ensure strict enforcement of security and privacy. The network enables front-line pharmacists to access to pertinent clinical records. We performed a series of tests (a "shakedown cruise") of the system and examined the role of the pharmacist as a counselor for patient compliance with prescribed therapeutic regimens. The results indicated the following: 1) This system provides an unequivocal means of communication between physicians and pharmacists. 2) This system is useful for judicious resolution of potential problems arising from separation of the domains of prescriber and dispenser. 3) A noteworthy finding was that community pharmacists devote substantial time/effort to counseling patients concerning their pharmacotherapeutic regimens. 4) Over 80% of patients responded with statements such as "Now I understand my medicines better," and "I am free of anxiety over my medication now." Thus the system provides a powerful tool to promote patient compliance based on pharmacological knowledge. Our future plans for the system include: 1) implementation of an inquiry/response protocol to enhance risk management; 2) online prescription issuance; and 3) expansion of the database used for patient counseling and improvement of the counseling method. Finally, physician-pharmacist collaboration through the system will contribute to a clear redefinition of their respective roles in community medical care services.