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Biomedical subjects

Y Takagi

Publications and source records attributed to Y Takagi.

At least 19 recordsLinked to original sources
PubMed1979

Inhibition of the recBC enzyme of Escherichia coli by specific binding of pyridoxal 5'-phosphate to DNA binding site.

Pyridoxal 5'-phosphate rapidly abolished the DNA-hydrolyzing activities as well as DNA-dependent ATP-ase activity of the recBC enzyme of Escherichia coli. Pyridoxal also had an inhibitory effect on the enzyme but less effective than that of pyridoxal 5'-phosphate. Pyridoxamine 5'-phosphate, pyridoxamine, or pyridoxine had no effect on the activities of the enzyme. The inhibition was rapidly reversed by dilution but could be made irreversible by reduction with sodium borohydride prior to dilution. This suggests the formation of Schiff base between pyridoxal 5'-phosphate and an epsilon-amino group of a lysine residue which is essential for the enzyme activity. Pyridoxal 5'-phosphate is a competitive inhibitor of DNA substrate but not of ATP. Furthermore, the presence of DNA substrate protected the enzyme from inactivation by the reduction but the presence of ATP showed no effect. Thus, the recBC enzyme appears to have an essential lysine residue at or near the DNA binding site of the enzyme, and the enzyme possesses two independent catalytic sites, such as a DNA binding site and an ATP binding site.

DNA, Bacterial↗
PubMed1979

Detection of collagen degradation products from subcutaneously implanted organic bone matrix.

Demineralized bovine bone powder was reduced with NaB3H4 to label the collagen crosslinks with tritium. The powder was enclosed in small nylon mesh pouches and implanted subcutaneously into rats for 3 weeks. Histological examinations revealed that multinuclear giant cells accumulated around the bone matrix, some in Howship's lacunae. Collagenous peptides containing intermolecular crosslinks were detected in the urea-soluble fraction extracted from the implant. Two crosslink-containing peptides were isolated from a dialyzable fraction: one contained dihydroxylysinonorleucine and the other hydroxylysinonorleucine. Both peptides had molecular weights of approximately 1000 estimated from the elution positions of gel filtration chromatography; and both had similar quantitative compositions of amino acids. There were no homologous peptides detected in a control experiment of the reduced bone matrix which was incubated in vitro with buffered saline for 1 week at 37 degrees C.

Animals↗
PubMed1979

Repair of ultraviolet-light damaged ColE1 factor carrying Escherichia coli genes for guanine synthesis.

Hybrid ColE1 plasmids called ColE1-coslambda-qua A or ColE1-coslambda-gal can be efficiently tranduced into various E. coli K-12 cells through packaging into lambda phage particles. Using these plasmids, repair of ultraviolet-light (UV) damaged ColE1 DNAs was studied in various UV sensitive E. coli K-12 mutants. (1) The host mutations uvrA and uvrB markedly reduced host-cell reactivation of UV-irradiated ColE1-coslambda-guaA. (2) Pre-existing hybrid ColE1 plasmids had no effect on the frequency of lambda phage-mediated transduction of another differentially marked hybrid ColE1 DNAs. (3) ColE1-coslambda-guaA and ColE1-coslambda-gal DNAs could temporarily but not stably co-exist in E. coli K-12 recA cells. (4) The presence of ColE1-coslambda-gal in uvrB cells promoted the repair of super-infected UV-irradiated ColE1-coslambda-guaA about 7-fold. (5) The same ColE1-coslambda-gal plasmid in a uvrB recA double mutant did not have this promoting effect. These results indicate that the effect of resident hybrid ColE1 plasmids is manifested by the host recA+ gene function(s) and suggest that ColE1 plasmid itself provides norecA+-like functions.

Chromosome Mapping↗
PubMed1979

Thiamin and pyridoxine requirements during intravenous hyperalimentation.

Studies were undertaken to determine rational dosages of vitamin B1 and B6 during long-term intravenous hyperalimentation, using more sensitive techniques than formerly used to evaluate B1 and B6 status. A standard vitamin combination, type A, (usually commercially available products) has been used up to now because of convenience, disregarding the effects of long-term administration. This combination lacks biotin, folic acid, and vitamin E and contains from 10 to 100 times the dietary allowances of such vitamins as B1, B2, B6, B12, and C. In response to the possibility of vitamin overdose, two new vitamin combinations, type B (from commercial products) and type C (a convenient and easily administered combination produced at the hospital) were developed in order to provide the normal dietary allowances and at the same time eliminate any harmful side-effects. From the results obtained, 5 mg/day for thiamin HCl and 3 mg/day for pyridoxine HCl in type B and type C were found to be a sufficient and safe level as opposed to 55 mg/day for thiamin HCl and 102 mg/day for pyridoxine HCl in type A.

Adult↗
PubMed1979

DNA sequences of the integration sites and inverted repeated structure of transposon Tn3.

The nucleotide sequence of the "inverted repeat" structure of the transposon Tn3 was determined by the DNA sequencing procedure developed by Maxam and Gilbert(1). The sequence, 38 base pairs long, is as follows: 5'-GGGGTCTGACGCTCAGTGGAACGAAAACTCACGTTAAG..(Tn3) 3'-CCCCAGACTGCGAGTCACCTTGCTTTTGAGTGCAATTC.. The integration of Tn3 is associated with a directly repeated sequence of 5 nucleotides appearing at each end of Tn3. The two directly repeated sequences so far determined are not the same. Furthermore, there is no homologous structure around the integration point of Tn3.

Base Sequence↗
PubMed1979

Lambda bacteriophage-mediated transduction of ColE1 deoxyribonucleic acid having a lambda bacteriophage-cohesive end site: selection of packageable-length deoxyribonucleic acid.

An in vitro recombinant ColE1-cos lambda deoxyribonucleic acid (DNA) molecule, pKY96, has 70% of the length of lambda phage DNA. The process of lambda phage-mediated transduction of pKY96 generated a small amount of transducing phage particles containing ColE1-cos lambda DNA molecules of 80 or 101% of the length of lambda phage DNA, in addition to those containing original pKY96 DNA molecules. The newly isolated larger plasmid DNAs were transduced 100 times more efficiently than pKY96 DNA. Their structures were compared with that of a prototype pKY96 DNA, and the mechanism of the formation of these molecules is discussed.

Bacteriophage lambda↗
PubMed1979

Location of a ColE1 deoxyribonucleic acid region that affects the plaque-forming ability of lambda-ColE1 hybrid bacteriophage.

The plaque-forming ability of a hybrid phage between plasmidColE1 and phage lambda carrying amber mutations in genes O and P was inhibited by the presence of ColE1 in suppressor-deficient Escherichia coli cells. ColE1 deoxyribonucleic acid regions concerned with this inhibition were examined by using various deletion and transposon insertion derivatives of ColE1, and it was found that the presence of the deoxyribonucleic acid region extending between 420 and 613 base pairs upstream from the initiation site of ColE1 deoxyribonucleic acid replication (J. Tomizawa, H. Ohmori, and R. E. Bird, Proc. Natl. Acad. Sci. U. S. A. 74: 1865--1869, 1977) was essential for this function.

Bacteriophage lambda↗
PubMed1979

Cross-sectional echocardiographic diagnosis of coronary artery aneurysms in patients with the mucocutaneous lymph node syndrome.

Real-time cross-sectional echocardiographic studies revealed the presence of coronary artery aneurysms in five patients with mucocutaneous lymph node syndrome. These lesions appeared as circular echo-free spaces with clearly-defined borders in sites corresponding to angiographically proven aneurysms. In 15 normal subjects who were studied only by noninvasive methods, and in 17 who had normal coronary arteriograms (including eight with the mucocutaneous lymph node syndrome), we found no similar echo findings. The aneurysms were in both right and left coronary arteries in three patients, and were confined to the left side in two. The mucocutaneous lymph node syndrome is an increasingly common condition in Japan which may be fatal due to myocardial infarction occurring in a setting of coronary aneurysm with thrombosis. Therefore, the ability to demonstrate coronary aneurysms noninvasively is of prognostic and potentially therapeutic value in this inadequately understood syndrome.

Adult↗
PubMed1979

Noninvasive diagnosis of pseudoaneurysm of the left ventricle.

The echocardiographic, scintigraphic, angiocardiographic and autopsy correlations in a patient with left ventricular pseudoaneurysm are presented. Interruption of the echo of the left ventricular wall and radioisotope image of pseudoaneurysm and its communication channel are demonstrated for the first time. The striking similarity of the radioisotope image to the angiographic image is noted. This study suggests that echocardiography has capability to visualize left ventricular wall defects, such as the perforation seen in this case and radioisotope ventriculography is equivalent to the invasive contrast technique. Both of the methods seem to be safe and specific for the diagnosis of left ventricular pseudoaneurysm.

Aged↗
PubMed1979

Clinical studies on human pancreatic deoxyribonuclease I.

Duodenal juice collected after administration of Boot's pancreozymin and secretin to patients with various pancreatic diseases was subjected to deoxyribonuclease I (DNase I) assay, as well as measurements of total volume, amylase output and maximum bicarbonate concentration. It was observed that the DNase I output is well correlated with each of three factors. The DNase I output was much lower in patients with chronic pancreatitis or pancreatic cancer than in control subjects, and DNase I output was even found to be low in patients suspected of having chronic pancreatitis, who did not give abnormal resulsts with other assay methods. These results imply that DNase I output may be a good indicator of exocrine function of the pancreas, and thus may be useful for early detection of pancreatic diseases.

Amylases↗