Search PubMed⌕ Search

Biomedical subjects

Y Miyazawa

Publications and source records attributed to Y Miyazawa.

At least 127 records · Page 7Linked to original sources
PubMed1984

Kawasaki disease complicated with mitral insufficiency. Autopsy findings with special reference to valvular lesion.

A case of mucocutaneous lymph node syndrome (Kawasaki disease, MCLS) complicated with mitral insufficiency is reported. This patient showed severe valvulitis, which was thought to be the main cause of mitral regurgitation. Two other patients with MCLS who did not present clinical signs of mitral insufficiency revealed the presence of mild valvulitis. The morphological alterations of cardiac valves were non-specific and mainly consisted of inflammatory infiltration, increment of fibrous connective tissue, and proliferation of small capillaries. In addition to the coronary aneurysms, the involvement of cardiac valves should receive attention as the sequelae of MCLS.

Aneurysm↗
PubMed1984

Conformational study of low molecular weight RNAs in solution by fluorescent probe.

Pseudouridine psi 73 in yeast 5.8S RNA was modified with 4-bromomethyl-7-methoxycoumarin(BMC). Temperature dependence of fluorescence intensity was measured and it was compared with UV-thermal melting curve. The region around psi 73 melts partially. Fluorescence intensity changes by titration with Mg2+ and it quenches largely by added iodide ion. The results are compared with those of BMC-modified psi 55 of tRNAPhe and psi 50 of 5S RNA reported in previous paper1-4.

Molecular Weight↗
PubMed1983

Partial melting of the segment around pseudouridine in yeast 5S RNA.

Pseudouridine in yeast 5S RNA was modified with 4-bromomethyl-7-methoxy-coumarin(BMC). Temperature dependence of fluorescence intensity was measured at various concentrations of Mg2+ and K+ cations. Hyperchromicity was also measured. At 100mM KCl and 10mM Mg2+, fluorescence intensity decreased with temperature as free BMC except a plateau at 45 degrees C. Withdrawal of Mg2+ from the buffer resulted in a large quenching at 20 degrees C and showed a gradual increase of fluorescence intensity with temperature, indicating a partial melting of the segment around pseudouridine. The temperature range agrees with the low melting temperature shown by hyperchromicity. In 10 mM KCl solution, the effects are more exaggerated.

Kinetics↗
PubMed1983

Magnesium cation induced conformational change of yeast tRNAPhe as studied by singlet-singlet energy transfer.

The A76 or A73 nucleotide at the 3'end of tRNAPhe was modified with the fluorescent reagent of proflavine (PF). The distance between the fluorophore of the 3'end and the Y base was measured by singlet-singlet energy transfer under the conditions of 10 mM and 0.01 mM Mg2+. The distance obtained at 10 mM Mg2+ is very close to that obtained by the X-ray diffraction method, while the distance at 0.01 mM Mg2+ is significantly smaller. The difference in the distance is explained as a result of destabilization of the tertiary structure with reduction of the Mg2+ concentration. The calculated distance between A73 and A76 shows the stacked conformation of the CCA strand. Fluorescent quenching experiments showed that the degree of stabilization of 3'end A76 by stacking is lower than that of A73. The removal of the CCA segment causes a difference not only in the thermal melting curves but also in the fluorescent wavelength of the Y base at 0.01 mM Mg2+. The results suggest that the 3'end CCA strand has a helical structure and contributes to the stabilization of the whole structure of tRNAPhe.

Energy Transfer↗
PubMed1983

Thermal and Mg2+ dependent behavior of pseudouridines at 39th and 55th of yeast tRNAPhe.

Pseudouridine psi 55 alone and both psi 55 and psi 39 in yeast tRNAPhe are selectively modified with fluorescent reagent of 4-bromomethyl-7-methoxycoumarin (BMC). The change of fluorescence intensity was measured as a function of temperature and Mg2+ concentration. Fluorescent quenching shows the stacked and unstacked forms of Y base, dependent on Mg2+ concentration. In contrast, Mg2+ had no effect on psi 55-BMC in T psi C loop at 20 degrees C. Fluorescence on titrating Mg2+ exhibited a kind of Mg2+-induced structural collapse at the corner of L-structure. The melting of psi 55-BMC takes place at 70 degrees C in 10mM Mg2+. At very low Mg2+ concentration, melting takes place at 35 degrees C. The melting of psi 39-BMC, located near the anticodon loop, was observed before the unfolding of the whole structure of tRNAPhe. A conformational transition of the anticodon loop takes place at a lower temperature and it is also expected in the quenching experiment of Y base.

Hot Temperature↗
PubMed1983

[Successful treatment in an adult case of congenital esophagobronchial fistula].

A case of congenital esophagobronchial fistula in a 46-year-old woman was described. The patient had presented with repeated attacks of pulmonary infection from her childhood and had been diagnosed pneumonia at least five or six times after the age of 18 years. Preoperative examinations including esophagogram by barium swallow revealed the existence of a fistula between middle thoracic esophagus and left B6 bronchus. The fistula was recognized as Type II of Braimbridge and Keith's classification, and successfully resected with left lower pulmonary lobe. Sixty-eight cases with congenital esophagobronchial fistula in adult including our own case have been reported in Japanese literature and about 70 cases in the literature of western countries. From the analysis of these cases, diagnostic basis on congenital origin of the fistula, useful diagnostic methods, types of the fistula and appropriate surgical procedures were discussed.

Bronchial Fistula↗