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Biomedical subjects

K Kojima

Publications and source records attributed to K Kojima.

At least 775 records · Page 43Linked to original sources
PubMed1979

[Superimpose of images by appending two simple video amplifier circuits to color television (author's transl)].

Images are very useful to obtain diagnostic informations in medical fields. Also by superimposing two or three images obtained from the same patient, various informations, for example a degree of overlapping and anatomical land mark, which can not be found in only one image, can be often found. In this paper characteristics of our trial color television system for the purpose of superimposing X-ray images and/or radionuclide images are described. This color television system, superimposing two images in each different color consists of two monochromatic vidicon cameras and 20 inches conventional color television in which only two simple video amplifier circuits are added. Signals from vidicon cameras are amplified about 40 dB and are directly applied to cathode terminals of color CRT in the television. This system is very simple and economical color displays, and enhance a degree of overlapping and displacement between images. As one of typical clinical applications, pancreas images were superimposed in color by this method. As a result, size and position of pancreas was enhanced. Also X-ray image and radionuclide image were superimposed to find exactly the position of tumors. Furthermore this system was very useful for color display of multinuclides scintigraphy.

Amplifiers, Electronic↗
PubMed1979

Enzymic synthesis of a new type of fucose-containing glycolipid with fucosyltransferase of rat ascites hepatoma cell, AH 7974F.

An alpha-fucosyltransferase activity has been demonstrated in rat ascites hepatoma AH 7974F cells catalyzing the transfer of L-fucose to asialo-GM1 prepared from bovine brain GM1 ganglioside to form a fucolipid in the presence of Triton X-100. The radioactive fucolipid was shown to be Fuc-(alpha1 leads to 2)-Gal-(beta1 leads to 3)-GalNAc-(beta1 leads to 4)-Gal-(beta1 leads to 4)-Glc-ceramide from the following results. The radioactive product coincided with authentic blood group H-active fucolipid from AH 7974F cell on thin-layer chromatography. The product formed a precipitation line not only with Ulex europeus lectin but also with eel anti-H serum on agarose gel plates. The terminal 14C-labeled fucose was released by Bacillus fulminans alpha(1 leads to 2)fucosidase as well as Charonia lampas alpha-fucosidase. The optimum pH value for the incorporation of L-fucose into asialo-GM1 was 5.8 in cacodylate/HCl buffer. The fucosyltransferase was highly specific for asialo-GM1.

Animals↗
PubMed1979

Calcium-dependent process in reduction of cell surface charge after x-irradiation.

The electrophoretic mobility (EPM) of rat erythrocytes and cultured melanoma cells decreased with time after X-irradiation in the presence of calcium at concentrations higher than 10 (-5) M. At 37 degrees C, the presence of calcium for the first 20 min of exposure was suffcient to induce the EPM reduction, and Ca 2+ administration subsequent to Ca 2+ -free incubation for 30 min following irradiation had no effect on EPM. At lower temperatures, from 10 down to 20 degrees C however, the effect of calcium on the reduction of EPM decreased drastically. If the cells were kept Ca 2+ -inonophore A23187 also induced to decrease in EPM only in the presence of Ca 2+. These results revealed the transitory existence of membrane condition reactive to extracellular Ca 2+ immediately after X-irradiation, which can be postponed at low temperatures. The reduction of EPM by Ca 2+ -ionophore might suggest that the influx of Ca 2+ is a step in the reduction of EPM after X-irradiation.

Animals↗
PubMed1979

Effect of butyrate on glycolipid metabolism of two cell types of rat ascites hepatomas with different ganglioside biosynthesis.

The effect of butyrate on glycolipid metabolism and morphological differentiation in the cell culture system of rat ascites hepatomas, AH 7974 of island-forming type and AH 7974F of free type, was studied. Both cell lines adhered to the substratum in the presence of 1 mM butyrate. In the case of AH 7974, the addition of butyrate induced a distinct morphological change but the other cell line showed no such conspicuous change. Butyrate-treated AH 7974 cells showed a 2 to 3-fold elevation of CMP-N-acetylneuraminic acid: lactosylceramide sialyltransferase activity to form N-acetylneuraminylgalactosylglucosylceramide (GM3). On the other hand, no enzyme activity could be detected in AH 7974F cells. Four glycosyltransferase activities involved in glycolipid synthesis, including sialyltransferase in AH 7974F cells, were reduced by butyrate. From these observations we concluded that sialyltransferase to form GM3, or TM3 itself, is prerequisite for the morphological alteration induced by butyrate.

Animals↗
PubMed1979

Early decrease in hyaluronidase-sensitive cell surface charge during the differentiation of Friend erythroleukemic cells by dimethyl sulfoxide.

Early membrane events in erythroid differentiation were investigated by means of cell electrophoresis utilizing cultured Friend erythroleukemia cell clones of different inducibility. The cell electrophoretic mobility decreased by 18% within 30 min of treatment with 1.5% dimethyl sulfoxide (DMSO) in highly inducible clones but not in noninducible clones. The reduced mobility persisted for 5 days of incubation with DMSO until hemoglobin synthesis. DMSO treatment for less than 16 hr and subsequent incubation without the drug resulted in the complete recovery of the mobility and no hemoglobin synthesis. Longer exposure to DMSO resulted in the loss of recovery of mobility and an increasing fraction of benzidine-positive cells seen on Day 5. Measurement of the electrophoretic mobility after the removal of acidic sugars by their specific enzymes suggested that hyaluronidase-sensitive negative charges were lost from the cell surface only in highly inducible clones. The mobility reduction associated with hyaluronic acid was also caused by other potent inducers (sodium butyrate, N-methylacetamide, and N,N-dimethylacetamide). These results suggest that the decrease in cell surface glycocalyx might be an early step in the induction of differentiation of Friend erythroleukemia cells.

Animals↗