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Biomedical subjects

M Takano

Publications and source records attributed to M Takano.

At least 325 records · Page 18Linked to original sources
PubMed1991

Nucleotide sequences of two genomic DNAs encoding peroxidase of Arabidopsis thaliana.

The peroxidase (EC 1.11.1.7)-encoding gene of Arabidopsis thaliana was screened from a genomic library using a cDNA encoding a neutral isozyme of horseradish, Armoracia rusticana, peroxidase (HRP) as a probe, and two positive clones were isolated. From the comparison with the sequences of the HRP-encoding genes, we concluded that two clones contained peroxidase-encoding genes, and they were named prxCa and prxEa. Both genes consisted of four exons and three introns; the introns had consensus nucleotides, GT and AG, at the 5' and 3' ends, respectively. The lengths of each putative exon of the prxEa gene were the same as those of the HRP-basic-isozyme-encoding gene, prxC3, and coded for 349 amino acids (aa) with a sequence homology of 89% to that encoded by prxC3. The prxCa gene was very close to the HRP-neutral-isozyme-encoding gene, prxC1b, and coded for 354 aa with 91% homology to that encoded by prxC1b. The aa sequence homology was 64% between the two peroxidases encoded by prxCa and prxEa.

Amino Acid Sequence↗
PubMed1991

FCR system in Hokkaido University Hospital.

The complete digital x-ray system using FCR is now being used in daily diagnosis as a part of the picture archiving and communications system (PACS) in Hokkaido University (HU) Hospital. This project is based on a 3-year plan started in 1988. In the first year (1988), six Fuji Computed Radiography (FCR) units (two FCR501, one FCR502, three FCR7000), PACS interfaces, and an optical disk system were installed. In the first year, about 60% of x-ray filming changed from the conventional technique to the FCR, and 60% of FCR images were transferred to PACS. In the second year, we began to use FCR in gastrointestinal (GI) study with two additional FCR7000s and three x-ray TV units. Then the percentage of plain films made by FCR increased to 80%. In the third year, angiographic studies will be converted to FCR. A specially designed built-in type FCR is under development to examine the entire spine. When this project is complete, almost all conventional radiography except chest tomography will be performed by FCR. The tomography x-ray computed radiography (CR) unit with automatic-imaging plate (IP) changer is expected to be developed soon.

Radiology Information Systems↗
PubMed1991

Renaturation, purification, and characterization of human truncated macrophage colony-stimulating factor expressed in Escherichia coli.

A human truncated macrophage colony-stimulating factor (M-CSF) encoding the amino acid residues from 3 to 153 of the native M-CSF was expressed by using a two-cistron expression system in Escherichia coli. The truncated M-CSF found in inclusion bodies was renatured and had CSF activity. Purification, which included a QAE-ZeTa preparative cartridge concentration step followed sequentially by HPLC on TSK-gel Phenyl-5PW and TSK-gel DEAE-5PW columns, gave an overall yield of 63.8%. The purified truncated M-CSF had a specific activity of 4 x 10(7) units/mg of protein. Peptide mapping of a lysylendopeptidase digest by reversed-phase HPLC confirmed the amino acid sequence predicted from the cDNA sequence. SDS-PAGE of the purified truncated M-CSF gave a single band at 17 kDa under reducing conditions and at 32 kDa under non-reducing conditions. Activated Thiol-Sepharose 6B column chromatography and other experiments failed to detect any free cysteine residue in spite of the existence of 7 cysteine residues in the truncated M-CSF subunit. These results indicate that it is a dimeric structure linked by one or more intermolecular disulfide bonds.

Amino Acid Sequence↗
PubMed1991

Trans-stimulation effect on H(+)-organic cation antiport system in rat renal brush-border membranes.

Trans-stimulation effect on tetraethylammonium (an organic cation) transport was examined in rat renal brush-border membrane vesicles. The uptake of [14C]tetraethylammonium at pH 6.0-8.5 was stimulated by preloading the membrane vesicles with unlabeled tetraethylammonium. When the uptake was measured in preloaded membrane vesicles in the presence of carbonyl cyanide p-trifluoromethoxyphenylhydrazone, stimulation was observed at high pH but not at low pH. These results suggest that the mechanisms of the trans-stimulation effect on organic cation transport are different depending on the pH. When pH is low, the trans-stimulation is due to generation of an outward H+ gradient, which in turn stimulates [14C]tetraethylammonium uptake by H(+)-[14C]tetraethylammonium exchange. In contrast, when pH is high, the stimulation is due to direct exchange of tetraethylammonium for [14C]tetraethylammonium.

Animals↗
PubMed1991

[A dramatic effect of continuous intra-arterial injected recombinant interleukin-2 immunotherapy on malignant hemangioendothelioma].

A malignant hemangioendothelioma (MHE) developed on the frontal scalp of an 83-year-old woman was treated with intralesional injection of recombinant interleukin-2 (rIL-2, TGP-3, Takeda Chemical Industries LTD, Osaka) which had lead the lesion to complete remission for 2 years and 9 months. After the period of the complete remission, the patient developed MHE lesion on the occipital scalp which rapidly enlarged to more than 10 cm in diameter within 7 days, though there was no recurrence of MHE on the frontal scalp at that time. Intra-arterial rIL-2 injection was conducted through the occipital artery which circulates around the tumor lesion, but resulted unsuccessful because of the obstruction of the artery. Continuous intra-arterial rIL-2 injection through bilateral superficial temporal arteries was conducted, and then the tumor lesion came to complete remission on both clinical and histological data. So far, the patient has been showing no local recurrence or metastasis for the period of 8 months. We conclude that continuous intra-arterial rIL-2 injection immunotherapy through superficial temporal arteries is the best way of all the treatment in cases with recurrent MHE located on occipital scalp.

Aged↗
PubMed1991

Transport of cyclosporin A in kidney epithelial cell line (LLC-PK1).

The characteristics of cyclosporin A transport have been studied in cultured kidney epithelial cell line LLC-PK1. The uptake of cyclosporin A by LLC-PK1 cells was time-dependent and reached a steady state at about 30 min. The initial uptake was saturable and was inhibited by cyclosporin A analogs, cyclosporin C and D and by verapamil, but not by metabolic inhibitors such as 2,4-dinitrophenol and rotenone. Cyclosporin A uptake as well as efflux was strongly dependent on temperature. The Arrhenius plot for cyclosporin A uptake was biphasic, whereas the Arrhenius plot for sulfanilamide uptake, which is transported by a simple diffusion, was linear. These results indicate that a specific mechanism is concerned in the transport of cyclosporin A in LLC-PK1, cells.

Animals↗
PubMed1990

[Quantitative assessment of mineral content in metacarpal bone with Fuji computed radiography].

A new microdensitometry method for quantitative assessment of bone mineral content using Fuji computed radiography (FCR) was developed and the results were compared with those obtained by the conventional film-screen method. Using both methods, X-ray pictures of the 2nd metacarpal bone were taken with a reference aluminum step wedge in nine normal subjects and nine parameters representing the width and density of bone marrow and cortex were calculated in the middle of the bone shaft. Interobserver reproducibility assessed for three parameters was significantly higher in the FCR method than the conventional one. The value of sigma GS computed by the FCR method, that is equivalent to the net bone density of the transverse section of the shaft, showed higher correlation with the one obtained by computed tomography in comparison with the conventional method. In our FCR method, moreover, interobserver reproducibility and accuracy was improved by employing automatic manipulation as much as possible in the process of calculation. The exposure dose in the FCR method could be reduced to half of the one in the conventional method without deteriorating the accuracy. In conclusion, our new microdensitometry method with FCR provides high accuracy and good reproducibility for the measurement of bone mineral content with small exposure dose and is likely to be useful for the long-term follow-up of the osteoporotic patients from the variety of causes.

Adult↗
PubMed1990

Genomic DNA structure of two new horseradish-peroxidase-encoding genes.

Genomic DNAs encoding the horseradish peroxidase (HRP) isozymes, prxC2 and prxC3, were cloned and sequenced. By comparing the sequences of the HRP isozyme-encoding genes, prxC1a and prxC1b and their cDNA [Fujiyama et al., Eur. J. Biochem. 173 (1988) 681-687], , it was concluded that prxC2 and prxC3 consisted of four exons and three introns as in the prxC1 gene family. The position of introns in coding regions were the same in all four prx genes. Genes prxC2 and prxC3 coded for 347 and 349 amino acid (aa) residues, respectively, including putative signal sequences at the N termini. In the flanking regions of both genes, putative promoters and polyadenylation signals were found. Nucleotide sequence homology in the coding region was 71% between prxC1a and prxC2, and 66% between prxC1a and prxC3. The aa sequence homologies in plant and microbial peroxidases were compared.

Amino Acid Sequence↗
PubMed1990

Selective modulation of the ATP-sensitive K+ channel by nicorandil in guinea-pig cardiac cell membrane.

Effects of a vasodilator, nicorandil (2-nicotinamidoethyl nitrate) on four kinds for cardiac K+ channels were investigated in guinea pig ventricular and atrial cells using inside-out patch recording combined with "oil-gate" concentration jump method. Nicorandil of 300 mumols/l failed to affect the inward-rectifier K+ channel and the Na(+)-activated K+ channel. The open probability of the muscarinic K+ channel, when activated by the application of GTP, was not changed by the drug. Nicorandil selectively increased the open probability of the ATP-sensitive K+ channel that was partly suppressed by intracellular ATP. The median effective concentration (EC50) of nicorandil was 74 mumols/l and Hill coefficient was 1.32 in the concentration-open probability relationship. The closing rate of the K+ channel by ATP was markedly delayed by the drug, whereas the open rate on removal of ATP was scarcely affected. Nicorandil had only little effect on this channel after run-down. It was concluded that nicorandil selectively activates the ATP-sensitive K+ channel mainly by modulating the ATP-dependent gate.

Adenosine Triphosphate↗
PubMed1990

Bone trabecular pattern analysis in Down syndrome with the use of computed panoramic radiography. Part II: Visual pattern analysis with the frequency and gradational enhancement.

Visual pattern analysis of mandibular bone trabeculation of 51 patients with Down syndrome and 78 normal persons was performed by using rotational panoramic radiography with a laser scan system. The findings for patients with Down syndrome were consistent with geromorphism, one of the somatic characteristics of Down syndrome.

Adolescent↗
PubMed1990

Diagnostic imaging of diseases affecting the mandible with the use of computed panoramic radiography.

Computed panoramic radiography was performed on patients with bone cyst, osteomyelitis, gingival cancer, and fibrous dysplasia, respectively, to determine the best imaging procedure for disease processes affecting the mandible. Gradational enhancement images for detection of density changes and frequency enhancement images for detecting changes in the margin and texture were effective in aiding the diagnosis of diseases of the mandible with the use of computed panoramic radiography.

Bone Resorption↗
PubMed1990

Thrombotic thrombocytopenic purpura in two patients with systemic lupus erythematosus: clinical significance of anti-platelet antibodies.

Thrombotic thrombocytopenic purpura (TTP) is a clinical syndrome of unknown etiology and has a high mortality rate due to disseminated platelet thrombi. However, the mechanism of platelet agglutination is not understood. Although an immunological mechanism has been suggested as the basis for the pathogenesis of TTP, any possible immune-mediated etiology remains unclear. The association of TTP with systemic lupus erythematosus (SLE) affords a unique opportunity to study such possibilities, because SLE is a prototype of autoimmune disease. This report describes two patients with SLE who developed TTP. The development of anti-platelet antibodies is one possible immunological mechanism for platelet agglutination in patients with SLE complicated by TTP. More importantly, patient J.Y., who had anti-platelet antibodies, responded dramatically to high doses of prednisolone.

Adult↗
PubMed1990

Anti-tumour efficacy of mouse spleen cells separated with Dolichos biflorus lectin (DBA) in experimental pulmonary metastasis of B16 melanoma cells.

Anti-tumour effector cells were generated through 4 days culture of normal C57BL/6 splenocytes in a medium containing concanavalin A supernatant and then fractionated with Dolichos biflorus lectin (DBA) into DBA+ (agglutinable with DBA) and DBA- (non-agglutinable with DBA) cells. The DBA- cells, infused intravenously into mice together with B16 melanoma cells, or adoptively transferred into mice 3 days after the injection of B16 cells, caused a marked decrease in the number of lung nodules, while the DBA+ cells exerted no effect. On the other hand, the DBA+ cells exhibited higher cytolytic activity in vitro than the DBA- cells in short-term 51Cr-release assays. Then, we analysed the mechanism of the strong anti-tumour activity of DBA- cells in vivo. We found that DBA- cells showed higher response to recombinant interleukin-2 (rIL-2) than DBA+ cells and proliferated very well with a small amount of IL-2. In addition, DBA- cells adhered more strongly to lung endothelial cells than DBA+ cells in response to rIL-1 or rTNF. Furthermore, DBA- cells produced larger amounts of macrophage activating factor (MAF) including IFN-gamma when cultured with B16 melanoma. Taken together, our results show that DBA- cells are effective in reducing experimental pulmonary metastases not only by the direct lytic activity but also by the indirect killing activity through the activated macrophage.

Animals↗