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Biomedical subjects

T Maeda

Publications and source records attributed to T Maeda.

At least 1,567 records · Page 87Linked to original sources
PubMed1977

Thrombocytopenic purpura occurring during the early phase of a mumps infection.

Thrombocytopenic purpura with reduced megakaryocyte count in bone marrow was found in a very early phase of a mumps infection in a one year 9 months old boy. No antithrombocyte antibodies were detected. Three weeks later, the mumps antibody titer in the serum was significantly elevated, and thrombocyte and megakaryocyte counts returned to normal.

Antibodies, Viral↗
PubMed1977

[Clinical study of carfecillin in chronic urinary tract infection (author's transl)].

1. Ten patients with chronic urinary tract infection by Pseudomonas aeruginosa or Proteus species were treated with carfecillin. Excellent response was seen in one case, fairly good in 5 cases and clinical effective rate was 60%. 2. The recurrence suppression effect of carfecillin was examined in two patients suffering from complicated urinary tract infection. In both cases, recurrence was not found when carfecillin was administered for a week after the effective pretreatment of carbenicillin, but found when administered for two weeks. 3. Side effects were observed in 3 cases (itching, tinnitus, diarrhea).

Aged↗
PubMed1976

Conformational transitioons of polypeptide chain elongation factor Tu. II. Further studies by electron spin resonance.

The conformational transitions of polypeptide chain elongation factor Tu (EF-Tu) associated with the ligand change from GDP to GTP and also with the displacement of GDP by elongation factor Ts (EF-Ts) have been investigated using the spin-labeling technique. Of the two reactive sulfhydryl groups in EF-Tu, the one essential for interaction with aminoacyl-tRNA was selectively labeled with various kinds of iodoacetamide or maleimide spin-labeling reagents. The electron spin resonance (ESR) spectra of EF-Tu-GDP labeled with these reagents generally consisted of two components, one narrow and one broad, corresponding to labels relatively weakly and strongly immobilized, respectively. The degree of immobilization and the ratio of the narrow to the broad components were different for each kind of label used. The spectra of spin-labeled EF-Tu-GDP changed markedly when its GDP moiety was replaced by GTP through incubation with phosphoenolpyruvate and pyruvate kinase [EC 2.7.1.40], the broad component increasing at the expense of the narrow component. The reversible nature of the conformational change was confirmed with EF-Tu labeled with a maleimide reagent. The GTP-induced spectral change was reversed upon conversion of labeled EF-Tu-GTP to EF-Tu-GDP by addition of excess GDP. A similar type of spectral change was also observed when spin-labeled EF-Tu-GDP was incubated with EF-Ts to form labeled EF-Tu-EF-Ts complex. The extent of the spectral change induced by EF-Ts was even greater than that induced by GTP. These results, together with those obtained by studies with hydrophobic and fluorescent probes (Arai, Arai, Kawakita, & Kaziro (1975) J. Biochem. 77, 1095-1106) indicate that a reversible conformational change is induced in EF-Tu near the sulfhydryl group that is essential for interaction with aminoacyl-tRNA.

Binding Sites↗
PubMed1976

Conformational transition of polypeptide chain elongation factor G as determined by electron spin resonance.

The conformational transition of the polypeptide chain elongation factor G (EF-G) induced by interaction with guanine nucleotide has been investigated by means of the spin-labeling technique. Various spin-label probes were attached specifically to the sulfhydryl group of the protein that is essential for binding to ribosomes, and the effects of these ligands on the electron spin resonance (ESR) spectra were examined. It was found that the ESR spectra of EF-G labeled with nitroxide maleimide reagents were modified by the addition of various guanine nucleotides such as GDP, GTP and, to a lesser extent, by Gpp(NH)p and Gpp(CH2)p, indicating that conformational changes accompany the binding of nucleotide ligand. However, the ESR spectra of labeled EF-G-GDP and EF-G-GTP were almost identical. On the other hand, when EF-G was labeled with nitroxide iodoacetamide reagents, a clear difference in the ESR spectra of EF-G-GDP and EF-G-GTP derivatives was observed. In this case, the spectral shape of the spin-labeled EF-G in the presence of GTP or its analogs, Gpp(NH)p or Gpp(CH2)p, was quite similar to that of free, unliganded EF-G derivative. These results, together with those previously obtained using hydrophobic probes (Arai, Arai, & Kaziro (1975) J. Biochem. 78, 243-246) demonstrate the existence of an EF-G-guanine nucleotide binary complex. They also indicate that there is a substantial difference in conformation between free EF-G, EF-G-GDP, and EF-G-GTP near the active site essential for interaction with ribosomes.

Binding Sites↗