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Biomedical subjects

E Kimoto

Publications and source records attributed to E Kimoto.

At least 55 records · Page 3Linked to original sources
PubMed1989

Effects of temperature and pH on hemoglobin release from hydrostatic pressure-treated erythrocytes.

The release of hemoglobin from human erythrocytes hemolyzed beforehand by hydrostatic pressure, osmotic pressure, and freeze-thaw methods was examined as a function of temperature (0-45 degrees C) and pH (5.5-8.8) at atmospheric pressure. Only in the case of high pressure (2,000 bar) did the release of hemoglobin increase significantly with decreasing temperature and pH. Maleimide spin label studies showed that the temperature and pH dependences of hemoglobin release were qualitatively explicable in terms of those of the conformational changes of membrane proteins. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis of membrane proteins showed the diminution of band intensities corresponding to spectrin, ankyrin, and actin in the erythrocytes hemolyzed by high pressure. Cross-linking of cytoskeletal proteins by diamide stabilized the membrane structure against high pressure and suppressed hemoglobin release. These results indicate that the disruption of cytoskeletal apparatus by high pressure makes the membrane more leaky.

Cross-Linking Reagents↗
PubMed1988

Monoclonal anti-Thy-1.2 antibody induced hematopoiesis in vivo.

The intravenous injection of a monoclonal anti-Thy-1.2 alloantibody (IgM class) induced a rapid increase in the number, and the ratio, of multipotent hematopoietic stem cells (CFU-S) in S-phase. The onset of hematopoiesis was thymus-independent. Reconstitution of lethally-irradiated mice with bone marrow cells from mice injected with antibody augmented the T-cell responsiveness to mitogens. No activation was observed in granulocyte/macrophage progenitors. The monoclonal antibody did not directly stimulate CFU-S in vitro, although hematopoietic activity could be found in the sera of antibody-injected mice. Immediately after injection, the antibody was found bound on Thy-1+ cells in spleen. No decrease in the number of peripheral T cells was seen. These results seem to indicate that Thy-1.2-positive cells bound with anti-Thy-1.2 alloantibody may secrete a factor which induces the proliferation of hematopoietic stem cells.

Animals↗
PubMed1988

Nonsurgical treatment of cholecystolithiasis with percutaneous transhepatic cholecystoscopy.

Early surgical intervention in acute cholecystitis is sometimes fatal to patients in the high-risk group. Since the technical development of ultrasonically guided puncture of the gallbladder, percutaneous transhepatic cholecystostomy has become a safer method for the treatment of acute cholecystitis. We have been developing percutaneous transhepatic cholecystoscopy procedures since 1981, and have used this method in 11 patients with cholecystolithiasis. In all cases, we were able to destroy the stones with the Nd-YAG laser, and remove the fragments with a basket catheter through the fistula. There were no severe complications from percutaneous transhepatic cholecystostomy or cholecystoscopy. This lithotomy technique is a safe and reliable nonsurgical technique for patients with cholecystolithiasis, especially the elderly high-risk group.

Aged↗
PubMed1987

Antioxidative activities of a reductant in the ultrafiltrate of human placental homogenate.

From the ultrafiltrate of human term placental homogenate, a reductant possessing an absorption maximum at 345 nm but not around 260 nm was isolated through the process of Sephadex G-25 gel filtration and DEAE-Sepharose column chromatography. This substance bore resemblance to a reduced nicotinate moiety of nicotinamide nucleotide in regard to a decay in 345 nm absorption and 457 nm fluorescence maximum on oxidation and to an irreversible shift of absorption maximum from 345 nm to 300 nm on acidification. Unlike ascorbate, its ferricytochrome c-reduction was not superoxide-dependent. It scavenged hydroxyl radical produced by Fenton reaction. It did not promote the iron-catalyzed lipid peroxidation of intact and heat-inactivated rat liver microsomes but it inhibited the NADPH or ascorbate-mediated microsomal lipid peroxidation. In the placenta, containing high concentrations of ascorbate and iron ion, 345 nm substance was understood as an antioxidative reductant.

Animals↗
PubMed1987

Polyol accumulation in human placenta and umbilical cord.

Ultrafiltrable metabolites in human term placenta and umbilical cord were analysed by means of 13C-NMR spectroscopy and gas-liquid chromatography. In these tissues, existing in a very reduced redox state, lactate and polyols (sorbitol, myoinositol and xylitol) were found to be the major accumulated intermediates of the glycolytic pathways. The cord tissue preferentially took up myoinositol.

Chromatography, Gas↗
PubMed1985

Oxidation of nitroxide radicals by an iron-hydrogen peroxide-amino acid system.

The oxidation of nitroxide radicals by the reaction of hemoglobin with hydrogen peroxide occurred using both FeSO4 and amino acids instead of hemoglobin. Tyrosine, phenylalanine, tryptophan, methionine and cysteine in globin were connected with the formation of the oxoammonium cation. Of these amino acids, tyrosine was especially effective in its oxidation. It was found that both the binding of nitroxide radicals to ferric iron and the activation of amino acids by hydroxyl radicals were important in the radical oxidation.

Amino Acids↗
PubMed1985

ESR spectral changes induced by chlorpromazine in spin-labeled erythrocyte ghost membranes.

Chlorpromazine interacted preferentially with membrane proteins rather than membrane lipids in the initial incorporation into human erythrocyte ghosts, as demonstrated by means of the fluorescence quenching and a maleimide spin label. In this state the membrane fluidity increased. At higher concentrations of chlorpromazine, the membrane fluidity decreased and a motionally restricted signal from fatty acid spin labels appeared predominantly. However, no such signal appeared in protein-free vesicles. The temperature and pH dependences of the outer hyperfine splitting of this restricted signal were very similar to those of bovine serum albumin. On the basis of sodium dodecyl sulfate-polyacrylamide gel electrophoresis of chlorpromazine-treated and -untreated ghosts, it was found that there was no significant difference in membrane proteins between both samples except for the changes of a few bands which were not directly concerned with the occurrence of this restricted signal. These results suggest that the fatty acid spin labels bind preferably to membrane proteins as the lipid domain becomes packed with chlorpromazine.

Chlorpromazine↗
PubMed1984

Oxidation of nitroxide radicals by the reaction of hemoglobin with hydrogen peroxide.

The ESR signal of 4-hydroxy-1-oxyl-2,2,6,6-tetramethylpiperidine in hemoglobin solution decreased drastically by the addition of hydrogen peroxide. The results of ion-exchange chromatography and sodium tetraphenylborate on the reaction solution showed an oxidation of the nitroxide radical to cation form. On the basis of the comparison of thin layer-chromatogram with the reaction products of the nitroxide radicals with HCl or Br2, the formation of 4-hydroxy-1-oxo-2,2,6,6- tetramethylpiperidinium cation was demonstrated. This result was supported by the 13C NMR measurement.

Cations↗
PubMed1984

Specifications of endoscopic ultrasonography.

In this paper we are going to describe the specifications of endoscopic ultrasonography using the equipment type III (Olympus GF- UMI ) on a basis of experiences in 45 patients during the past one year. The main body of the instrument is a standard type of gastroscope, Olympus GF-B3. The ultrasonic probe is incorporated into the tip of the endoscope. This instrument makes possible endoscopic visualization of the UGI tract and, at the same one time, allows us to do ultrasonic scanning of internal organs in the neighbourhood of the UGI tract. The better resolution of ultrasonic image is definitely obtained with this instrument than that of the conventional ultrasonography because its ultrasonography is intraluminally performed with high frequency transducer of 7.5 MHz and the image is never disturbed by the gastroduodenal gas nor the abdominal wall tissues. Endoscopic ultrasonography using the equipment type III is useful as a new diagnostic tool of great value in gastroenterology. However, there still remain a few mechanical points to be improved. It is desired that the rigid section of the tip of the endoscope is shortened more and the stability of the endoscopic image is guaranteed. These improvements would heighten its diagnostic value.

Cystadenoma↗
PubMed1983

Properties of the strongly immobilized signal observed in spin-labeled erythrocytes.

A strongly immobilized signal from fatty acid spin labels was observed in human erythrocytes treated with oxidizing agents such as glutaraldehyde, hydrogen peroxide, phenylhydrazine and copper-ortho-phenanthroline. This signal was also observed in freshly prepared ghosts treated with potassium superoxide and in old erythrocyte ghosts. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis of these samples demonstrated the diffuse, nondiscrete bands of high molecular weight due to the cross-linking of membrane proteins. The temperature and pH dependences of the outer hyperfine splitting of this signal were very similar to those of bovine serum albumin. We propose that the strongly immobilized signal reflects the interaction of the lipids with the cross-linked products of membrane proteins.

Adult↗
PubMed1983

A study on the reaction of human erythrocytes with hydrogen peroxide.

Membrane fluidity of human erythrocytes treated with H2O2 (1--20 mM) was studied using three kinds of fatty acid spin labels. A strongly immobilized signal appeared on exposure of erythrocytes to H2O2 but was not observed in either H2O2- or Fenton's reagent-treated ghosts or lipid vesicles prepared from H2O2-treated erythrocytes, indicating that the appearance of this signal necessitates the reaction of hemoglobin with H2O2 and is not due to lipid peroxidation. The ESR spectrum of maleimide-prelabeled erythrocytes showed an isotropic signal and the rotational correlation time (tau c) increased as the concentration of H2O2 was increased. Furthermore, maleimide labeling of H2O2-pretreated erythrocytes showed a strongly immobilized component, in addition to a weakly immobilized component. From the relative ratio of the signal intensity of hemoglobin and membrane proteins, it was found that label molecules bound predominantly to hemoglobin. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis of H2O2-treated erythrocytes demonstrated globin aggregation. Therefore, the changes in the ESR signal observed on H2O2 treatment may be due to some change in hemoglobin, such as globin aggregation or its binding to the membranes. The ESR spectrum of H2O2-treated erythrocytes at -196 degrees C is characterized by signals of nonheme ferric iron type (g equal to 4.3), low spin ferric iron, and free radical type at g equal to 2.00. At higher H2O2 concentrations, the ESR lines due to low spin ferric iron became broad and their peak heights decreased, compared with that at g equal to 2.00 or 4.3. These results indicate that oxidative stress such as decrease of membrane fluidity, lipid peroxidation, and globin aggregation in H2O2-treated erythrocytes is dependent on the reaction of hemoglobin with H2O2.

Adult↗