Search PubMed⌕ Search

Biomedical subjects

K Ueda

Publications and source records attributed to K Ueda.

At least 757 records · Page 42Linked to original sources
PubMed1992

Human P-glycoprotein transports cortisol, aldosterone, and dexamethasone, but not progesterone.

We expressed human MDR1 cDNA isolated from the human adrenal gland in porcine LLC-PK1 cells. A highly polarized epithelium formed by LLC-GA5-COL300 cells that expressed human P-glycoprotein specifically on the apical surface showed a multidrug-resistant phenotype and had 8.3-, 3.4-, and 6.5-fold higher net basal to apical transport of 3H-labeled cortisol, aldosterone, and dexamethasone, respectively, compared with host cells. But progesterone was not transported, although it inhibited azidopine photoaffinity labeling of human P-glycoprotein and increased the sensitivity of multidrug-resistant cells to vinblastine. An excess of progesterone inhibited the transepithelial transport of cortisol by P-glycoprotein. These results suggest that cortisol and aldosterone are physiological substrates for P-glycoprotein in the human adrenal cortex and that substances that efficiently bind to P-glycoprotein are not necessarily transported by P-glycoprotein.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1992

Modulation of C2 and C3 gene expression of human peripheral blood monocytes by interleukin 1 beta, interferon gamma, tumor necrosis factor alpha and lipopolysaccharide.

The effect of interleukin 1 beta (IL-1 beta), interferon gamma (IFN-gamma), tumor necrosis factor alpha (TNF alpha) and lipopolysaccharide (LPS) on the expression of the C2 and C3 genes in human adherent monocytes was studied. Stimulation of monocytes with IFN-gamma increased both C2 and C3 mRNA. IL-1 beta also increased C2 mRNA level, whereas C3 gene expression was not enhanced. TNF alpha failed to increase either C2 or C3 mRNA. LPS increased C2 mRNA, but suppressed C3 gene expression. These results suggest that C2 and C3 production by monocytes is regulated by IL-1 beta and IFN-gamma in the local tissues.

Complement C2↗
PubMed1992

Periodicity of episode occurrences in rapid cycling affective disorders.

We analyzed the medical records of nine patients with severe rapid cycling affective disorders (RCAD), and determined the cycle of mania occurrences by calculating the period between two successive onsets of mania for each patient. Using the cycle as the index we devised a cycle-oriented diagram by dividing the observation period by the index cycle, and visually studied the mode of episode occurrences. In seven patients, the onset of mania generally followed the index cycle, but sometimes shifted from the day estimated by the index cycle. The shift seemed to be caused by a cycle other than the index cycle, which appeared temporarily in the course. The period between two successive onsets of mania was often several times longer than the index cycle length. In patients with RCAD, some sort of periodic rhythms may possibly control the course of episode occurrences on a continuing basis.

Adult↗
PubMed1992

Enhancement of hepatitis-B surface-antigen expression by 5-azacytidine in a hepatitis-B-virus-transfected cell line.

The human hepatoblastoma-derived cell line HB611 secretes hepatitis-B surface antigen (HBsAg) and hepatitis-B e antigen (HBeAg) into the medium. Hepatitis-B-virus (HBV) DNA integrated into the cellular genome was found to be hypermethylated. When the cells were treated with 5-azacytidine for 3 days, the level of HBsAg in the medium increased, while the level of HBeAg remained constant. The level of alpha-fetoprotein (AFP) decreased with the 5-azacytidine treatment. Southern blot analysis of DNA digested with HpaII or MspI showed that 5-azacytidine treatment resulted in hypomethylation of the integrated HBV DNA, suggesting that 5-azacytidine increased HBsAg production in the cells through hypomethylation of the HBV genomic DNA.

Azacitidine↗
PubMed1992

Specific drug binding by purified lipid-reconstituted P-glycoprotein: dependence on the lipid composition.

We fused P-glycoprotein with beta-galactosidase at the C-terminus aiming to study the mechanism of drug binding of P-glycoprotein in reconstitution experiments. Expression of the fusion protein in NIH 3T3 cells conferred a multidrug-resistant phenotype, suggesting that beta-galactosidase fusion at the C-terminus does not affect the functions of P-glycoprotein. The fusion protein was partially purified by simple immunoprecipitation with anti-beta-galactosidase polyclonal antibody, and its [3H]azidopine binding property was investigated in the presence of various compositions of liposomes. The purified P-glycoprotein, after reconstitution into liposomes, was capable of binding [3H]azidopine. When the cholesterol content of liposomes was increased to a weight ratio of 20%, the specific binding activity of the partially purified fusion protein was stimulated, and when the cholesterol content was increased higher, the binding activity decreased. The binding was specifically decreased by competition with vinblastine. Stigmasterol was less effective, and ergosterol was the least effective in stimulating the specific binding.

3T3 Cells↗
PubMed1992

[Experimental study on the usefulness of the autoperfusion balloon catheter in maintaining the blood supply to the distal organs].

Autoperfusion Balloon Catheters (APBC) were inserted into the renal arteries of seven dogs for about two and a half hours. Abdominal aortography showed renal arterial flow of the kidney obstructed by APBC. Macroscopic and microscopic examination revealed no significant changes in the resected specimen. It is concluded that APBC is useful in cases of proximal arterial occlusion by maintaining the blood supply to the distal organs for relatively short periods and that it can be used for the treatment of rupture of arteries which feed critical organs.

Animals↗
PubMed1992

Quercetin, a bioflavonoid, inhibits the increase of human multidrug resistance gene (MDR1) expression caused by arsenite.

Expression of the MDR1 gene, which encodes P-glycoprotein, is increased under some stress conditions. We have reported that quercetin, a bioflavonoid, inhibits the expression of heat-shock proteins. We have identified the effects of quercetin on the MDR1 gene expression in the human hepatocarcinoma cells line, HepG2. The increase of P-glycoprotein synthesis and MDR1 mRNA accumulation caused by exposure to arsenite were inhibited by quercetin. The CAT assay suggested that quercetin suppressed the transcriptional activation of the MDR1 gene after exposure to arsenite. Although many drugs that prevent the P-glycoprotein function have been reported, this is the first report to describe the inhibition of MDR1 expression by a reagent.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1992

Heat-shock responsive elements in the induction of the multidrug resistance gene (MDR1).

The MDR1 gene, considered to be involved in multidrug resistance of cancer cells, is expressed in liver, kidney, small intestine and the blood-brain barrier. We investigated MDR1 gene expression in the well-differentiated hepatoma cell line HepG2 after exposure to several stresses and found that sodium arsenite treatment increased MDR1 gene expression 2.6-fold. Deletion analysis of the MDR1 promoter indicated that the transcriptional activation after exposure to arsenite depends on a 60-bp region containing two heat-shock responsive elements.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1992

Expression of MBP-HCV NS1/E2 fusion protein in E. coli and detection of anti-NS1/E2 antibody in type C chronic liver disease.

To characterize the putative NS1/E2 (non-structural protein 1/envelope 2) domain of HCV (hepatitis C virus), we expressed the hydrophilic three-quarters of this domain in a form of MBP (maltose binding protein) fusions in Escherichia coli. When we checked the positive frequency of antibody to this fusion protein, 17% of patients with type C chronic liver disease had this antibody. However, they were all positive for HCV-RNA in sera. These results suggest that the appearance of anti-NS1/E2 antibody does not serve as evidence of viral clearance.

ATP-Binding Cassette Transporters↗
PubMed1992

P-glycoprotein. ATP hydrolysis by the N-terminal nucleotide-binding domain.

Two ATP-binding domains are found in members of the family of ATP-dependent transport proteins, which includes P-glycoprotein and cystic fibrosis transmembrane conductance regulator. To investigate the involvement of the two ATP-binding domains in the ATPase activity of P-glycoprotein, full-length and the 5'-half of human MDR1 cDNA, which encodes P-glycoprotein, were fused with the Escherichia coli lacZ gene and expressed in NIH3T3 cells. Immunoprecipitated full-length P-glycoprotein beta-galactosidase showed ATPase activity with apparent specific activity of 180 nmol/mg/min, a value higher than previously reported, in the presence of phospholipids, suggesting that stabilization of the transmembrane domains is necessary for ATP hydrolysis. N-terminal half P-glycoprotein-beta-galactosidase also showed ability to hydrolyze ATP but with slightly lower specific activity. Both ATPase activities showed similar characteristics when the effect of several inhibitors was analyzed, indicating that the N-terminal ATP-binding domain contains all residues necessary to hydrolyze ATP without interacting with the C-terminal ATP-binding domain.

3T3 Cells↗