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Biomedical subjects

K Inui

Publications and source records attributed to K Inui.

At least 487 records · Page 27Linked to original sources
PubMed1986

Mechanisms of gentamicin transport in kidney epithelial cell line (LLC-PK1).

The characteristics of gentamicin transport have been studied by using cultured kidney epithelial cell line LLC-PK1. The uptake of gentamicin by the LLC-PK1 cells appeared to be linear for 30 min and reached the equilibrium at day 1. Marked stimulation of gentamicin uptake was observed on the development of a confluent cell density, accompanied by the increases of marker enzyme activities and Na+-dependent D-glucose transport in the apical membranes. Gentamicin uptake was inhibited by metabolic inhibitors such as rotenone and 2,4-dinitrophenol, and was inhibited competitively in the presence of other aminoglycosides. Depending on the external calcium concentration, calcium ionophore A23187 stimulated gentamicin uptake, whereas ethylene glycol bis(beta-aminoethyl ether)N,N1-tetraacetic acid, a calcium chelator, inhibited gentamicin uptake. These results suggest that gentamicin uptake by the LLC-PK1 cells may be mediated via specialized transport system, and calcium ion movement may play an important role as a regulatory factor for this transport system.

Aminoglycosides↗
PubMed1985

Distinction of three types of D-glucose transport systems in animal cells.

Immunoblotting of plasma membrane fractions from rat kidney cortex with antibody to human erythrocyte glucose transporter showed a single major cross-reacting material of 48K in basolateral membrane fractions possessing a facilitated diffusion system for D-glucose, but not in brush border membrane fractions which have a Na-dependent active transport system. Cytochalasin B inhibited D-glucose uptake in basolateral membrane vesicles but not in brush border vesicles. Cross-reacting materials of 44-55K were detected in several animal cells exhibiting facilitated diffusion systems, including a hormone dependent system. These results indicate molecular difference between glucose transporters of facilitated diffusion systems and active transport systems.

Adipose Tissue↗
PubMed1985

Cimetidine transport in rat renal brush border and basolateral membrane vesicles.

The transport of cimetidine by rat renal brush border and basolateral membrane vesicles has been studied in relation to the transport system of organic cation. Cimetidine inhibited [3H]tetraethylammonium uptake by basolateral membrane vesicles in a dose dependent manner, and the degree of the inhibition was almost the same as that by unlabeled tetraethylammonium. In contrast, cimetidine inhibited the active transport of [3H]tetraethylammonium by brush border membrane vesicles more strongly than unlabeled tetraethylammonium did. In agreement with the transport mechanism of tetraethylammonium in brush border membranes, the presence of an H+ gradient ([H+]i greater than [H+]o) induced a marked stimulation of cimetidine uptake against its concentration gradient (overshoot phenomenon), and this concentrative uptake was inhibited by unlabeled tetraethylammonium. These results suggest that cimetidine can share common carrier transport systems with tetraethylammonium in renal brush border and basolateral membranes, and that cimetidine transport across brush border membranes is driven by an H+ gradient via an H+-organic cation antiport system.

Animals↗
PubMed1985

Specific binding activities and cyclic GMP responses by atrial natriuretic polypeptide in kidney epithelial cell line (LLC-PK1).

Receptor binding activities and cyclic GMP responses by alpha-human atrial natriuretic polypeptide (alpha-hANP) and its fragments were studied in a kidney epithelial cell line (LLC-PK1). Binding of 125I-alpha-hANP to the cells at 0 degrees C was saturable, time-dependent and reversible, indicating the presence of a single class of binding sites. alpha-hANP (7-23)NH2 fragment inhibited most effectively the specific binding of 125I-alpha-hANP to the LLC-PK1 cells, followed by alpha-hANP (17-28) and alpha-hANP (8-22), while alpha-hANP (1-6) and alpha-hANP (24-28) did not. alpha-hANP stimulated the formation of cyclic GMP in the LLC-PK1 cells dose-dependently. Although no fragments of alpha-hANP used were effective for cyclic GMP formation in the LLC-PK1 cells, alpha-hANP (7-23) NH2 antagonized the action of alpha-hANP on cyclic GMP formation. These data suggest that the LLC-PK1 cells retain specific receptors for atrial natriuretic polypeptide (ANP) and respond to ANP by stimulating cyclic GMP formation, and therefore this cell line may be useful for studying the mechanism of action for ANP in renal tubular cells.

1-Methyl-3-isobutylxanthine↗
PubMed1985

Specific receptors for atrial natriuretic polypeptide on basolateral membranes isolated from rat renal cortex.

The binding of alpha-human atrial natriuretic polypeptide (alpha-hANP) to brush border and basolateral membranes isolated from the rat renal cortex was studied at 0 degree C by a rapid filtration technique. Specific binding of 125I-alpha-hANP to basolateral membranes reached a steady state at 4 hr. The binding to brush border membranes was maximal at 5-15 min and then rapidly decreased. The analysis of incubation mixtures with basolateral membranes revealed little degradation of 125I-alpha-hANP during the 4-hr incubation, while there was extensive degradation of the ligand with brush border membranes during the 30-min incubation. High affinity binding of 125I-alpha-hANP was demonstrated on basolateral membranes but not on brush border membranes. These data suggest that specific receptors for alpha-hANP are localized on basolateral membranes of the renal cortex.

Animals↗
PubMed1985

Involvement of nipple and areola in early breast cancer.

In 141 mastectomy specimens, performed for invasive or noninvasive carcinomas, histopathologic study was performed to assess the extent of nipple-areola involvement by the tumor. In this study, patients were excluded if the tumor was located beneath the areola; and nipple and/or areola abnormalities were clinically present. Tumor involvement of the nipple and/or areola was found in 44 of 141 specimens (31%), with intraductal growth in 36 (82%) of 44, stromal invasion in 3 (7%), and ductal and stromal invasion in 5 (11%). Analysis of nipple-areolar involvement with consideration of the different variables indicates that it occurred in association with tumor size, tumor-areola distance, and histologic type. Such information provides clinically relevant guidelines in decision making for limited breast surgery.

Adenocarcinoma, Mucinous↗
PubMed1985

H+-gradient-dependent active transport of tetraethylammonium cation in apical-membrane vesicles isolated from kidney epithelial cell line LLC-PK1.

Transport of [3H]tetraethylammonium (NEt4+), an organic cation, has been studied by using apical-membrane vesicles isolated from cultured kidney epithelial cell line LLC-PK1. The uptake of NEt4+ by apical-membrane vesicles was osmotically sensitive, time-dependent and saturable. The presence of an H+ gradient ([H+]i greater than [H+]o) induced a marked stimulation of NEt4+ uptake against its concentration gradient (overshoot phenomenon), and this concentrative uptake was inhibited by HgCl2. These results suggest that apical membranes isolated from the LLC-PK1 cells retain the transport characteristics of NEt4+ similar to those observed in renal brush-border membranes.

Animals↗
PubMed1985

The gene coding for a sphingolipid activator protein, SAP-1, is on human chromosome 10.

SAP-1 is a sphingolipid activator protein found in human tissues required for the enzymatic hydrolysis of GM1 ganglioside and sulfatide. It appears to be missing in patients who have a genetic lipidosis resembling juvenile metachromatic leukodystrophy. Using rabbit antibodies against human SAP-1 it could be visualized in extracts from cultured human skin fibroblasts after sodium dodecylsulfate-polyacrylamide gel electrophoresis, followed by electroblotting to nitrocellulose membrane and immunochemical staining (Western blotting). A series of 23 human-Chinese hamster ovary cell hybrids containing different human chromosomes were examined. The parent Chinese hamster ovary cells did not have a reacting protein in the region of human SAP-1. Only in the eight hybrid clones containing human chromosome 10 was a reacting protein identified. Other chromosomes were excluded by this method. Therefore the gene for SAP-1 and the genetic mutation resulting in a fatal lipidosis are located on human chromosome 10.

Animals↗
PubMed1985

Late onset GM2 gangliosidosis: an alpha-locus genetic compound with near normal hexosaminidase activity.

A non-Jewish child with late onset GM2 gangliosidosis is described. Tissues from the patient had near normal hexosaminidase A (hex A) activity using 4-methylumbelliferyl-2-acetamido-2-deoxy-beta-D-glucopyranoside (MU-glcNAc) as substrate, and deficient activity when assayed with the 6-sulphate derivative of MU-glcNAc (MU-glcNAcS) or GM2 in the presence of activator. We present evidence that this patient is a genetic compound for different alpha-subunit mutations. The father's tissues have hex A activity in the heterozygote range when assayed with MU-glcNAcS, but normal activity using MU-glcNAc; the mother's tissues have activities toward both substrates in the heterozygote range. These results emphasize the pitfalls of using only MU-glcNAc for the diagnosis of unusual variants of GM2 gangliosidosis.

Acetylglucosamine↗
PubMed1985

Differences in effects on drug absorption between dihydroxy and trihydroxy bile salts.

The effect of a dihydroxy bile salt, sodium taurodeoxycholate (STDC), on drug absorption from rat small intestine was investigated in comparison with that of trihydroxy one, sodium cholate (STC). The enhancement or inhibitory effects on the absorption of various model drugs by STDC bore similar tendency to those by STC, and the magnitude was greater than the latter. The absorption of sulfaguanidine was enhanced by STDC, which solubilized the phospholipids from the mucosal barrier membrane in addition to the STC-like, or ethylenediaminetetraacetate-like action. STDC inhibited the absorption of sulfadimethoxine contrary to the insignificant effect by STC. The direct action of STDC on the mucosal membrane reduced the absorption in addition to the physicochemical action, such as micellar complex formation. Quinine absorption was inhibited in the presence of STDC, which can be explained by the micellar complex formation. Possible mechanisms of the differences in the effect of STDC and STC were discussed in relation to their micellar properties.

Animals↗
PubMed1985

Gentamicin binding to brush border and basolateral membranes isolated from rat kidney cortex.

The interaction of gentamicin with renal cortex of rats has been studied in vitro by means of a binding assay to brush border and basolateral membranes. Gentamicin specifically bound to plasma membrane fractions, compared to other subcellular fractions. Gentamicin binding to brush border and basolateral membranes was markedly inhibited by polycations such as spermine, and was slightly inhibited by high concentrations of tetraethylammonium. The treatment of phospholipase A2 to both types of membranes increased gentamicin binding, although the treatments by proteolytic enzymes and sulfhydryl reagent did not affect the binding. Gentamicin binding was increased in the brush border membranes treated with acidic phospholipids, whereas it was decreased in the membranes treated with calcium. Judging from the determination of membrane surface charge by metachromasy of cationic dye, basolateral membranes seemed to contain more anionic sites than brush border membranes. The alterations of gentamicin binding described above correlated with the changes of anionic charge on the membranes, indicating a charge interaction between gentamicin and anionic binding sites on the membranes. The addition of other aminoglycoside antibiotics to the incubation mixture induced significant reductions in the binding of gentamicin in the order of aminoglycosides according to their positive charge. The present results suggest that the characteristics of gentamicin binding to brush border and to basolateral membranes are essentially similar, and therefore the renal accumulation of gentamicin may be regulated by the transport of gentamicin across both plasma membranes.

Aminoglycosides↗
PubMed1985

Treatment of malignant pleural effusion.

Two hundred consecutive patients with malignant pleural effusion were reviewed. The pathologic etiology of malignant pleurisy was: primary lung cancer in 123 cases; five, mesothelioma; and 72 cases secondary to metastatic tumors. Adenocarcinoma of the lung and mammary cancer were the most frequent tumors causing malignant pleural effusion. The modalities employed in local treatment consisted of thoracocentesis in 62 patients, tube thoracotomy in 111 cases with local instillation of adriamycin, MMC, CQ, 5FU, OK432 or talc. Surgical procedures including pleuropneumonectomy or reduction surgery of the tumor with decortication were performed in ten patients. Tube drainage with local instillation of drugs was more effective than thoracocentesis with or without local therapy. Excellent initial results were obtained in patients who received reduction surgery with decortication and pleurodesis. Results of cytologic investigation were positive in 157 cases (78.5 percent). The tumor cells disappeared in 79.4 percent of primary cancer pleurisy cases and 81.1 percent of patients with metastases while disappearance or significant decrease in pleural effusion following treatment was obtained in 75.2 and 77.8 percent respectively. The median survival was 11.3 months in primary cases, and 11.7 months in patients with metastases.

Adult↗