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K Takao

Publications and source records attributed to K Takao.

At least 37 records · Page 2Linked to original sources
PubMed1999

Arginyl-tRNA-protein transferase activities in crude supernatants of rat tissues.

A fluorescent HPLC method for the assay of arginyl-tRNA-protein transferase (R-Transferase) activity was applied to obtain quantitative data of the enzyme activity in rat tissues for the first time. In this assay, the major problem was a significant hydrolysis of the substrate, N-aspartyl-N'-dansylamido-1,4-butanediamine, and the product, N-arginylaspartyl-N'-dansylamido-1,4-butanediamine (ArgAsp(4)DNS) by aminopeptidases in crude samples such as 105000g supernatants (105S) of tissue homogenates. As bestatin inhibited the hydrolysis of ArgAsp(4)DNS, a standard-addition method in the presence of bestatin, using a partially purified R-Transferase preparation from hog kidney as a standard, made it possible to measure directly R-Transferase activities in 105S with a short incubation time and sufficient reliability. It was found by the established method that of 14 tissues examined, stomach was rich in the R-Transferase activity with the highest specific activity, suggesting a target tissue for the future studies on R-Transferase to elucidate its physiological significance.

Aminoacyltransferases↗
PubMed1999

Biological activities of 1,1,6-trisubstituted indanes: beyond magainin 2.

MSI-78 is a peptide analog of naturally occurring magainin 2 isolated from the skin of Xenopus laevis. The peptide is known to have one of the strongest antibacterial activities in magainin 2 analogs against methicillin-resistant Staphylococcus aureus (MRSA). To find novel compounds superior to MSI-78, we have further designed, synthesizing 1,1-di(4-aminobutyl)-6-benzylindane (PM4) and 1,1-dibenzyl-6-(4-aminobutyl) indane (PM5), and tested their inhibitory ability of the growth of S. aureus. In an in vitro assay, PM4 showed the same antibacterial activity against the bacterium as MSI-78, and non-hemolytic activity against human red blood cells (RBCs) at the MIC (minimum inhibitory concentration) value, in contrast to the latter. On the other hand, PM5 showed stronger antibacterial activity than MSI-78, but being still accompanied with hemolysis at the MIC value. Otherwise, stronger decarboxylase activity for oxaloacetate was observed in PM5, rather than magainin 2 analogs or Oxaldie 1 as a control peptide, but not in PM4.

Amino Acid Sequence↗
PubMed1999

Inhibition of human chymase by suramin.

Chymase is a chymotrypsin-like protease localized in mast cells in complexes with heparin. In the present study, we demonstrated that suramin, a hexasulfonated naphthylurea used as an anti-cancer drug, inhibits the activity of purified human chymase in vitro. The inhibition was ionic-strength-dependent. It was observed that suramin competed with heparin-Sepharose gel for binding to chymase and the inhibition of chymase activity by suramin was partially impaired by heparin. Our results show that suramin may become a prototype of a new type of chymase inhibitor because of its unique character.

Antineoplastic Agents↗
PubMed1998

Azide accelerates the decay of M-intermediate of pharaonis phoborhodopsin.

Natronobacterium pharaonis has retinal proteins, one of which is pharaonis phoborhodopsin, abbreviated as ppR (or called pharaonis sensory rhodopsin II, psR-II). This pigment protein functions as a photoreceptor of the negative phototaxis of this bacterium. On photoexcitation ppR undergoes photocycling; the photoexcited state relaxes in the dark and returns to the original state via several intermediates. The photocycle of ppR resembles that of bR except in wavelengths and rate. The cycle of bR is completed in 10 ms while that of ppR takes seconds. The Arrhenius analysis of M-intermediate (ppR(M)) decay which is rate-limiting revealed that the slow decay is due to the large negative activation entropy of ppR. The addition of azide increases the decay rate 300-fold (at pH 7); Arrhenius analysis revealed decreases in the activation energy (activation enthalpy) and a further decrease in the activation entropy.

Journal Article↗
PubMed1998

[Combined hepatic resection and removal of portal vein tumor thrombi].

Portal thrombectomy with extended hepatectomy for extensively progressive primary liver cancer (Vp 3), in which the tumor thrombus has spread beyond the first portal branches, will make other non-surgical treatments possible and improve patients quality of life. We have performed extensive resections in 15 cases of such Vp 3 liver cancer. One patient with huge HCC involving retrohepatic IVC underwent in situ extended left hepatectomy without reconstruction of IVC, resulting in postoperative renal failure because of thrombosis in the bilateral renal veins, but 14 other patients' postoperative courses were uneventful. Ten of 14 patients relapsed within one year, but these patients underwent non-surgical treatments, resulting in improvement in the quality of life. The 1-, and 3-year survival rates were 55.6% and 32.5%, respectively.

Adult↗
PubMed1997

Effects of corticosterone on 5-HT1A and 5-HT2 receptor binding and on the receptor-mediated behavioral responses of rats.

The effects of corticosterone after binding to 5-HT1A and 5-HT2 receptors were studied in rats. Binding of [3H]8-hydroxy-2-(di-n-propylamino) tetralin (8-OH-DPAT) to 5-HT1A receptors in the hippocampus decreased 24 h after both acute and chronic (14 day) administration of CORT (50 mg/kg, s.c.). Chronic, but not acute, CORT treatment increased [3H]ketanserin binding to 5-HT2 receptors in the frontal cortex. Receptor-mediated behavioral responses were also examined following acute and chronic CORT treatment. Flat body posture and hypothermia induced by 8-OH-DPAT, a 5-HT1A receptor agonist, were attenuated following chronic, but not acute, CORT administration. (+/-)-1-(2,5-dimethoxy-4-iodophenyl)-2-aminopropane (DOI), a 5-HT2 receptor agonist, induced wet-dog shakes, but not hyperthermia and this response was increased 24 h after the chronic administration of CORT. These findings indicate that both 5-HT1A and 5-HT2 receptor functions were changed following chronic exposure to high levels of CORT. Such changes in these receptor systems may play an important role in the etiology of affective disorders.

8-Hydroxy-2-(di-n-propylamino)tetralin↗
PubMed1997

Dissociation of Oct-1 from the nuclear peripheral structure induces the cellular aging-associated collagenase gene expression.

The cellular aging-associated transcriptional repressor that we previously named as Orpheus was identical to Oct-1, a member of the POU domain family. Oct-1 represses the collagenase gene, one of the cellular aging-associated genes, by interacting with an AT-rich cis-element in the upstream of the gene in preimmortalized cells at earlier population-doubling levels and in immortalized cells. In these stages of cells, considerable fractions of the Oct-1 protein were prominently localized in the nuclear periphery and colocalized with lamin B. During the cellular aging process, however, this subspecies of Oct-1 disappeared from the nuclear periphery. The cells lacking the nuclear peripheral Oct-1 protein exhibited strong collagenase expression and carried typical senescent morphologies. Concomitantly, the binding activity and the amount of nuclear Oct-1 protein were reduced in the aging process and resumed after immortalization. However, the whole cellular amounts of Oct-1 protein were not significantly changed during either process. Thus, the cellular aging-associated genes including the collagenase gene seemed to be derepressed by the dissociation of Oct-1 protein from the nuclear peripheral structure. Oct-1 may form a transcriptional repressive apparatus by anchoring nuclear matrix attachment regions onto the nuclear lamina in the nuclear periphery.

Base Sequence↗
PubMed1997

Antibacterial activity of (+/-) 6-benzyl-1-(3-carboxypropyl) indane; a possible way to identify leading novel anti-H. pylori agents.

Magainin 2, isolated from the skin of the Xenopus laevis, is an antimicrobial peptide which reacts directly with the biological membrane to lyse various bacteria from negative and positive microorganisms. In a previous report, we showed that (+/-)1-(4-aminobutyl)-6-benzylindane (PM2), which mimicked the conformation of the side-chains of a complementary unit on the amino acid sequence of magainin 2 analogs, expressed the in vitro antibacterial activity not only against Helicobacter, pylori (ATCC43526, ATCC43579), but also against Escherichia coli (ATCC25922) and Staphylococcus aureus (ATCC25923). In addition, PM2 caused human blood red cells (RBCs) to lyse at the minimum inhibitory concentration (MIC) value. Based on the antibacterial activities of 9-phenylnonanoic acid (pC9c), we further synthesized (+/-)-6-benzyl-1-(3-carboxypropyl) indane (PM2c), which replaced a positive charge of PM2 with a negative one, and tested the biological activities. PM2c had the ability to inhibit the growth of H. pylori strains, but its activity to inhibit the growth of E. coli and S. aureus was not detected and weak, respectively. Moreover, PM2c showed non-hemolytic activity against RBCs at the MIC value. These results indicate the possibility that PM2c may be more useful than PM2 either alone or in combination with well-known therapeutic agents for the treatment of H. pylori infection.

Animals↗
PubMed1997

[The study of continuous infusion chemotherapy with low-dose cisplatin and 5-fluorouracil for patients with primary liver cancer].

Twelve patients with unresectable primary liver cancer (hepatocellular carcinoma and cholangiocarcinoma) and postoperative recurrence of primary liver cancer received continuous arterial or systemic infusion of low-dose CDDP/5-FU. This infusion chemotherapy was continued for five days, discontinued for two days, and repeated four weeks as one course basally. The partial response rate in patients with HCC or CCC treated with intra-arterial infusion was 20% and 33%, respectively. The rate in patients with HCC or CCC treated with systemic infusion was 0% and 33%, respectively. The response rate included decrease of tumor markers in all patients with HCC or CCC was 33% and 67%, respectively. These results suggest that low-dose CDDP/5-FU therapy may be effective in patients with CCC. Severe side effects such as gastro-duodenal ulcer (4 cases) and pseudomembranous colitis (1 case) were observed. The careful management of side effects should be required during this therapy.

Aged↗
PubMed1996

The saline ballooning method for peritoneal dissection during laparoscopic herniorrhaphy.

To improve the safety and speed of the peritoneal dissection, we developed a saline ballooning method in which a dull needle is inserted lateral to the inferior epigastric vessels under direct laparoscopic visualization to a tissue plane just superficial to the peritoneum. Then, saline solution is injected. As a result, the peritoneum is easily separated from the spermatic cord and inferior epigastric vessels. Furthermore, bleeding is minimized during dissection of the peritoneum.

Blood Loss, Surgical↗
PubMed1996

[Effects of intra-hepatic arterial injection of mitoxantrone for hepatocellular carcinoma].

Twenty patients with unresectable hepatoma, recurrent hepatoma or metastatic liver cancer were treated by intra-hepatic arterial injection of mitoxantrone, and its effectiveness and side effects were studied. In 35.5% of the patients, complete or partial responses were seen. The survival intervals after the beginning of therapy were from one to 21 months (mean, 9.4 months) and one-year survival ratio was 56.3%. Red blood cell, leukocyte, and platelet counts diminished significantly one week later after administration of mitoxantrone compared with the pre-administration levels. Severe hepatic dysfunction has not been experienced.

Adult↗
PubMed1995

Chronic forced swim stress of rats increases frontal cortical 5-HT2 receptors and the wet-dog shakes they mediate, but not frontal cortical beta-adrenoceptors.

We studied the effects of chronic forced swim stress on 5-HT2 receptors and beta-adrenoceptors in the rat frontal cortex. The number of 5-HT2 receptors was increased immediately after the last chronic stress, but not after an acute stress. In vivo, the number of wet-dog shakes induced by a 5-HT2 receptor agonist, (+/-)-1-(2,5-dimethoxy-4-iodophenyl)-2-aminopropane (DOI), was increased 24 h after the last chronic stress. However, the concentrations of 5-HT and 5-hydroxyindole acetic acid (5-HIAA), measured by high pressure liquid chromatography (HPLC), were not altered by this stress. Binding sites for [3H]CGP-12177, i.e., beta-adrenoceptor sites, were unchanged after both the acute and the chronic stress. These results suggest that, in the rat, the chronic forced swim stress increases the number of frontal cortical 5-HT2 receptors and the number of wet-dog shakes mediated by these receptors, while the number of frontal cortical beta-adrenoceptors is not increased by this treatment.

Amphetamines↗
PubMed1995

Molecular cloning and sequencing of the hcs gene, which encodes 3-hydroxy-3-methylglutaryl coenzyme A synthase of Schizosaccharomyces pombe.

We have cloned and sequenced the hcs gene, which is thought to encode a 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) synthase consisting of 447 amino acids, from the fission yeast Schizosaccharomyces pombe. The predicted amino acid sequence of the hcs product of S. pombe has homology with the HMG-CoA synthase of rat (47.8%), chicken (49.2%), hamster (47.1%) and human cells (46.9%). One of the hcs genes was replaced with a marker gene in the diploid cell. No viable hcs-disrupted haploid was isolated after tetrad dissection, suggesting that the hcs gene is essential for growth. However the hcs-defective mutant could be grown on a medium containing 5 mg/ml mevalonate. These results strongly support that the hcs gene encodes HMG-CoA synthase and S. pombe contains a single copy of the hcs gene.

Amino Acid Sequence↗
PubMed1995

[Two cases of Kniest dysplasia--ocular manifestations].

We report ocular findings from 2 children with Kniest dysplasia. Both eyes of the 2 patients had abnormal long axial length causing high myopia, and vitreoretinal degeneration. The vitreous cavity of case 1 (a 15-year-old boy) which contained fibrous clouded membranous structures floating in the retrolental space and dense opacity at the temporal-inferior portion, was optically empty. Case 2 (a 7-year-old boy) had cortical and posterior subcapsular opacity of the lens, and also veil-like vitreous opacity in the periphery. Their common retinal changes were characterized as perivascular lattice degeneration and white without pressure in various degrees. They have not yet shown cataract or retinal detachment which needs surgical treatment, but close ophthalmological follow up will be necessary for their favorable prognosis. The literature on vitreoretinal degeneration such as Wagner's disease or Stickler syndrome may indicate the relation of Kniest dysplasia to similar diseases. Because they might have different clinical courses and visual prognosis according to the original biosynthetic disorders, we emphasized the importance of orthopedic diagnosis regarding such vitreoretinal degeneration with constitutional bone diseases.

Adolescent↗
PubMed1994

A region of the muscarinic-gated atrial K+ channel critical for activation by G protein beta gamma subunits.

Complementary DNAs encoding two types of inwardly rectifying K+ channels, GIRK1 and IRK1, have been cloned from rat atrium and mouse macrophage, respectively. GIRK1 expressed in Xenopus oocytes was activated by acetylcholine when m2 muscarinic acetylcholine receptor was coexpressed. The acetylcholine-induced activation of GIRK1 was enhanced by coexpression with the G protein beta 1 gamma 2 subunit but not the beta 1 gamma 1 or alpha subunits. Deletion of the C-terminus of GIRK1 impaired the channel activation associated with the beta 1 gamma 2 subunit. Moreover, replacement of the C-terminus of IRK1 with that of GIRK1 produced a chimera channel that was activated by the beta 1 gamma 2 subunit, whereas intact IRK1 was not activated by the beta 1 gamma 2 subunit. These findings define the C-terminus of GIRK1 as a regulatory region for the G protein beta gamma subunit.

Animals↗
PubMed1993

Role of 5-HT1A receptors in the forced swimming wheel test in reserpine-treated mice.

The antidepressant-like effect of 8-hydroxy-2-(di-n-propylamino)tetralin(8-OH-DPAT), a selective 5-HT1A receptor agonist, was studied in the forced swimming wheel test in reserpine-treated mice. 8-OH-DPAT and the antidepressant imipramine, dose-dependently increased the number of turns of a water wheel made by mice. This effect of imipramine (30 mg/kg, i.p.) was enhanced by reserpine treatment 24 hr before the test. The effect of 8-OH-DPAT (0.3 mg/kg, i.p.) was also enhanced in reserpine-treated mice. This enhanced effect of 8-OH-DPAT was blocked by pretreatment with the 5-HT1A receptor antagonists, (-)-propranolol (3 mg/kg, i.p.) and NAN-190 (1 mg/kg, i.p.), but was not blocked by a beta-blocker, (-)-atenolol (3 mg/kg, i.p.). 8-OH-DPAT did not affect locomotor activity in the reserpinized mice and did not affect the reduction of monoamine content induced by reserpine. These results suggest that the effect of 8-OH-DPAT in increasing the number of turns of the wheel made by mice was exerted through a 5-HT1A receptor and that this effect did not reflect only changes in the locomotor activity of the mice.

8-Hydroxy-2-(di-n-propylamino)tetralin↗