Search PubMed⌕ Search

Biomedical subjects

A Honda

Publications and source records attributed to A Honda.

230 records · Page 13Linked to original sources
PubMed1980

Effect of bleomycin, neocarzinostatin, and hydroxyurea on the preformed carrageenin granuloma in rats: mechanism of hyaluronic acid accumulation by bleomycin.

In order to elucidate whether the effects of bleomycin on the production or accumulation of intercellular substances by rat carrageenin granuloma are specific to bleomycin or a general response of the granulomatous tissue to the substances interfering with DNA synthesis, we examined the wet (or dry) weight and various components (DNA and glycosaminoglycans) in the granulomatous tissue of rats treated with bleomycin, neocarzinostatin, or hydroxyurea. The changes in various parameters of the granuloma after withdrawal of the inhibitors of DNA synthesis were different with different inhibitors tested. The highest recovery rate of DNA contents in the granulomatous tissue observed after withdrawal of bleomycin. It was also found that bleomycin caused much higher accumulation of hyaluronic acid in rat carrageenin granuloma than neocarzinostatin or hydroxyurea. This accumulation mechanism was indicated to be the results of the inhibition of mucopolysaccharidase activities via cells rather than those of the stimulation of glycosaminoglycan synthesis. These findings obtained in our experimental granuloma-system are of particular importance in considering the mechanism of the side effects of bleomycin.

Animals↗
PubMed1979

The effect of aging on the synthesis of hexosamine-containing substances from rat costal cartilage. A decrease in sulfation of chondroitin sulfate with aging.

The amount of glycosaminoglycan (GAG) in dry costal cartilage tissue of rats decreased with aging, while the GAG content in mg DNA (unit cartilage cell) remained the same with aging. These results can be explained by the finding that the total number of cartilage cells decreased with aging. Electrophoretic analysis showed that chondroitin 4-sulfate was the major GAG in rat costal cartilage of various ages. Rat costal cartilage of different ages was incubated with radioactive precursors, and newly synthesized GAG was prepared and the radioactivity analyzed to determine the biosynthetic activity. As to changes in the radioactivity uptake with aging per mg dry cartilage tissue, aging influenced [35S]sulfate incorporation into GAG more significantly than [3H]glucosamine incorporation into GAG. There was a significant decrease in the specific radioactivity of [35S]sulfate per mg DNA (unit cartilage cell), whereas the specific radioactivity of [3H]glucosamine per mg DNA did not change significantly with aging. Both the total sulfotransferase activity and the specific activity per mg DNA decreased significantly with aging. Analysis of disaccharide units formed after chondroitinase ABC digestion of labeled GAG isolated from young and old cartilage showed that the percentage of incorporation of [3H]glucosamine into deltaDi-OS increased significantly with aging. These results suggested that the appearance of nonsulfated positions in the structure of the chondroitin sulfate chain increased with aging. On the basis of gel chromatography on Bio-Gel A-1.5 m no significant difference in the approximate molecular size of chondroitin sulfate was observed between the young and old GAG samples. The present study indicated that the sulfation of chondroitin sulfate chains from rat costal cartilage decreased with the process of aging.

Aging↗
PubMed1976

Proteoglycan complexes from bovine heart valve. Fractionation by density-gradient centrifugation and gel filtration under dissociative conditions.

Proteoglycan complexes from collagenase [EC 3.4.24.3]-indigestible materials of bovine heart valves were extracted with 4 M guanidinium chloride, purified by ion-exchange column chromatography in a urea-containing solution, then fractionated by density-gradient centrifugation under dissociative conditions. Electrophoretic characteristics and enzymic susceptibility of the density-gradient fractions revealed that the glycosaminoglycans constituting the proteoglycan complexes in this indigestible materials were mainly dermatan sulfate in the top three fractions, and dermatan sulfate and chondroitin sulfates in the bottom fraction; a minor constituent which was common to all the fractions was hyaluronic acid. A gel-like substance (Fr. Ig) at the top of the gradient, amounting to about 25% of the loaded dry sample, contained only a trace of hydroxyproline (less than 1%) and was composed of proteodermatan sulfate, glycoprotein, and a small amount of hyaluronic acid. Sodium dodecyl sulfate-polyacrylamide gel electrophoretic analyses of Fr. Ig with 2-mercaptoethanol showed that the major part of the proteins in this gel-like substance was cross-linked by disulfide bridges. Chromatography of Fr. Ig on Sepharose 4B in buffered 4 M guanidinium chloride containing 2-mercaptoethanol, together with the electrophoretic patterns of the resulting fractions, suggested that proteodermatan sulfate was not associated with hyaluronic acid through covalent bonds. The amino acid composition of Fr. Ig was very similar to that reported in the literature for "dermatan sulfate-protein complex", and "structural glycoprotein" or "acidic structural protein".

Amino Acids↗
PubMed1974

Studies on transfer ribonucleic acids and related compounds. 8(1). Further studies on aromatic phosphoramidates as a protecting group for phosphomonoesters.

Stability of aromatic phosphoramidates was studied using 2',3'-O-dibenzoyluridine 5'-phosphoramidates and N,2',3'-O-tribenzoylcytidine 5'-phosphate. The effect of dicyclohexylcarbodiimide in this mixture was investigated. Decomposition of the anilidate was slower in the presence of DCC. Substituted anilidates of uridine 5'-phosphate were synthesized and the stability of these amidates in anhydrous pyridine was studied.2'-O-Benzoyluridine 3'-phosphoranilidate and the corresponding beta-naphthylidate were compared in their stabilities in anhydrous pyridine, 50% aqueous pyridine and 80% acetic acid. 2'-O-Benzoyluridine 3'-phosphoro-beta-naphthylidate was used for synthesis of dinucleotides.

Acetates↗
PubMedDate not supplied

Moyamoya syndrome in a patient with Down syndrome presenting with chorea.

An 11-year-old girl with Down syndrome is reported with moyamoya syndrome; she presented with chorea and mental regression, but had no hemiplegia or convulsions. Magnetic resonance imaging and magnetic resonance angiography were valuable for diagnosis of moyamoya syndrome. It is suggested that moyamoya syndrome be considered as a possible cause of involuntary movements in Down syndrome patients.

Child↗
PubMedDate not supplied

A murine model of zygomycosis by Cunninghamella bertholletiae.

Infections by Cunninghamella bertholletiae have been on the increase in recent years. However, little is known about this fungus and its infection. To clarify the pathogenicity of C. bertholletiae, we made a murine model, and to our knowledge, the first infectious model of this fungus. ICR mice pretreated with cortisone acetate and cyclophosphamide were inoculated intratracheally with 5 x 10(5) spores of C. bertholletiae. About half of the mice died by day 4 and 90% died by day 9. C. bertholletiae was cultured from the lungs, and the pathological analysis disclosed diffuse hyphal growth in the lungs, resulting in necrosis in the later stage. Angioinvasion with alveolar hemorrhage was extremely pronounced from the early stage, and this was the most characteristic feature of this infection. Treatment with amphotericin B showed only minimal improvement of survival, comparable to the poor result of this treatment in actual human cases. In fact, our model has many similarities to the actual human infection by C. bertholletiae, and will be useful for further investigations of this infection.

Amphotericin B↗
PubMedDate not supplied

Cytotoxicity of adriamycin-containing immunoliposomes targeted with anti-ganglioside monoclonal antibodies.

GM2 and GD2 have been intensely studied as tumor antigens of neuroectodermal-origin tumors. We have established several mouse or rat IgM anti-ganglioside GM2 and GD2 MoAbs and applied them in antigen-specific drug delivery. In the immunofluorescence assay, anti-GM2 MoAbs bound to neuroblastoma cells and leukemia cells, and anti-GD2 MoAb bound to neuroblastoma cells and melanoma cells. Sulfhydryl subunits of reduced IgM were directly coupled to maleimide groups on the surface of the liposomes followed by the incorporation of adriamycin by the use of Na+/K+ chemical gradient. The resultant immunoliposomes had a size of 86 nm-diameter containing approximately 400 molecules of adriamycin in its unilamellar structure and 17 molecules of the MoAb on its surface. Mouse anti-GM2 MoAb lost the binding specificity when covalently bound to the liposomes. The immunoliposome coupled with mouse anti-GD2 MoAb retained targeting activity to the antigen-positive neuroblastoma cells, IMR-32. However, it did not kill IMR-32 cells, probably because the amount of adriamycin taken up by the tumor cell was below the fatal amount. The immunoliposome coupled with rat anti-GM2 MoAbs delivered adriamycin to the neuroblastoma cells, IMR-32, and leukemia cells, TYH, in the antigen-specific manner. It also target-specifically suppressed the (3H)thymidine-uptake of the cells while the same concentration of adriamycin in the free form killed all the cell lines examined. IMR-32 cells had GM2 and GD2 in almost the same amounts, and interacted with either mouse anti-GD2 MoAb--immunoliposome or rat anti-GM2 MoAb-immunoliposome. The different cytotoxic activities of the two immunoliposomes against IMR-32 cells was probably due to the difference in the facility of internalization of the immunoliposomes after binding.

Animals↗