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Biomedical subjects

K Kawabe

Publications and source records attributed to K Kawabe.

At least 271 records · Page 15Linked to original sources
PubMed1983

3-D envisioning by real time perpendicular bi-plane echocardiography (simultaneous multifrequency ultrasonography-III).

Simultaneous dual B-modes, the tomographic plane of which can be moved freely keeping the intersecting angle always perpendicular, was devised and based on simultaneous multifrequency ultrasonography (Miwa, et al, 1981). Dual probes, the ends of which are linked by two arms and three nodes with potentiometers are used to display the intersecting line on the both B-mode images by computation. Both images can be displayed together on one CRT, or separately on the different CRTs. This has proved to be a great help for understanding the 3-D structure of heart. Quantitative dimension and displacement speed measurement of 3-D structure of heart such as myocardium thickness, inner diameter of ventricle, and their changing speed, can be performed very exactly at the accurate three dimensional orientation to the heart. We have also recognized that measuring beam for M-mode must be guided to an exact orientation by this technology. Otherwise, unexpected error has been introduced very usually, if guided only by conventional single B-mode due to lack of information of three dimensional incident angle to the wall, valve,..

Biophysical Phenomena↗
PubMed1982

Studies on reconstituted myoglobins and hemoglobins. I. Role of the heme side chains in the oxygenation of myoglobin.

To clarify the functional role of the 2- and 4-side chains of heme in myoglobin oxygenation, we synthesized several new hemins carrying nonnatural side chains at positions 2 and 4, reconstituted myoglobins with them, and investigated their optical, ionization, and oxygen-binding properties. The absorption maxima for most of the reconstituted myoglobins except those reconstituted with hemins having carbonyl groups, no matter whether they are oxy-, deoxy-, or carbon monoxy-form, shifted by at most 20 nm toward shorter wavelengths than protoheme-myoglobin. The absorption spectrum is more affected by resonance effects than by inductive effects of the peripheral side chains of heme. Differences in optical and oxygenation properties between isomeric myoglobins carrying hemes with different side chains at positions 2 and 4 indicate that the 2- and 4-side chains of heme are functionally nonequivalent, as previously shown by Sono and Asakura [(1975) J. Biol. Chem. 250, 5227-5232] for monoformyl-monovinylheme myoglobins. Modification of the 4-side chain exerts greater influence on the oxygen affinity than that of the 2-side chain. The extrapolation method proposed by Sono and Asakura to correct for the protein factor seems to be applicable only as a special case and does not apply to the isomeric myoglobins studied by us. There was not correlation between pKa of the met-form and the oxygen pressure at half saturation, implying that the electronic effect of the side chains is not decisive for the oxygen affinity of myoglobin. The bulkiness of the 2- and 4-side chains, on the other hand, appear to have a certain relation to the affinity but is not a dominant factor. In addition to these factors, specific stereochemical considerations are required to explain all the oxygenation data for the various reconstituted myoglobins. We have proposed a stereochemical mechanism based on the movement of the heme group upon ligation of native myoglobin.

Acylation↗
PubMed1982

Studies on reconstituted myoglobins and hemoglobins. II. Role of the heme side chains in the oxygenation of hemoglobin.

To clarify the functional role of the 2- and 4-side chains of heme in hemoglobin we prepared several hemins carrying nonnatural side chains at positions 2 and 4, reconstituted human adult hemoglobins with them, and investigated their optical and oxygen binding properties. The absorption maxima for all these reconstituted hemoglobins, no matter whether they are oxy-, deoxy-, or carbon monoxy-form, shifted toward shorter wavelengths than those for protoheme-hemoglobin. As in the case of myoglobin (Kawabe, K., et al. (1982) J. Biochem. 92, 1703-1712), the absorption spectrum is more significantly affected by resonance effects than by the inductive effects of the peripheral heme substituents. Contrary to the case of myoglobins, the spectral difference between pemptoheme-hemoglobin and isopemptoheme-hemoglobin and that between 2-isopropyl-4-vinyl-deuteroheme-hemoglobin and 2-vinyl-4-isopropyldeuteroheme-hemoglobin were very small. All the reconstituted hemoglobins used in this study showed higher oxygen affinity and reduced cooperativity in oxygen binding than native hemoglobin. We have shown that the 2- and 4-side chains are functionally nonequivalent and that modification of the 4-side chain exerts greater influence on oxygen affinity than modifying the 2-side chain. The magnitude of the Bohr effect and response to 2,3-diphosphoglycerate and inositol hexaphosphate were reduced in the reconstituted hemoglobins. We have proposed a stereochemical mechanism based on constraint of heme movement before ligation against the tight distal side of the heme pocket.

Animals↗
PubMed1982

[Clinical effect of long-term administration of PSK in a combination in patients with malignant urologic cancer].

Long-term administration of PSK was made in 40 patients with urological cancer. Mean duration of the administration was 201, 358 and 243 days for the patients with bladder cancer, renal cancer and other urological cancers, respectively. The clinical evaluations were performed by the standard of Japan Society for Cancer Therapy and historical control study. In some cases, it seemed that the immunological therapy by PSK was a benefit to some degree. However, more accurate evaluation should be made by the matched control study.

Adenocarcinoma↗
PubMed1981

Transurethral ultrasonotomography of the prostate.

Newly developed transurethral ultrasonic scanners were used to study 20 patients with histologically proven prostatic cancer. Fifty-two patients with or without other prostatic disease were also evaluated. The characteristic findings of prostatic cancer were asymmetry of the shape (85%), ill-defined contour (75%), protruded areas from the boundary (70%), elongation of anteroposterior diameter (65%), and enlargement of the prostate (65%). In addition, transurethral ultrasonography delineated a clearer contour of the prostate compared with the transrectal procedure.

Humans↗
PubMed1979

Influence of steric factors on oxygen binding. I. Studies on 2,4-diisopropyldeuteroheme-myoglobin.

Sperm whale apomyoglobin was recombined with 2,4-diisopropyldeuterohemin to form 2,4-diisopropyldeuteroheme-myoglobin and its various physico-chemical properties were investigated to get an insight into the structural and functional role of the peripheral vinyl groups. 2,4-Diisopropyldeuteroheme-myoglobin showed a four times lower oxygen affinity at 25 degrees C and larger enthalpy and entropy changes of oxygenation than the corresponding values of native myoglobin. 2,4-Diisopropyldeuteroheme-metmyoglobin shows a pKa value of 9.68 which is higher than those of native metmyoglobin and mesoheme-metmyoglobin. The rate of autooxidation of oxy-form was about seven times larger in 2,4-diisopropyldeuteroheme-myoglobin than in native myoglobin. The electron-donating effect of isopropyl groups does not give straightforward explanation for these anomalous properties of 2,4-diisopropyldeuteroheme-myoglobin. It is proposed that site and stereospecific van der Waals' interaction between the polypeptide side chains and the peripheral 2,4-diisopropyl groups may weaken the interaction between the bound oxygen molecule and the distal His, resulting in the decrease in the stability of oxyform.

Animals↗