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Biomedical subjects

M Ono

Publications and source records attributed to M Ono.

At least 847 records · Page 47Linked to original sources
PubMed1983

Verapamil enhances the efficiency of DNA-mediated gene transfer in mammalian cells.

Treatment of Ltk- cells with the calcium antagonists, verapamil and diltiazem, but not nifedipine, causes a 3-fold enhancement of the frequency of transfer of the cloned gene for herpes simplex virus thymidine kinase (HSV-tk). The frequency of phenotypic expression of the HSV-tk DNA was 20 to 34 times higher than that of genotypic transformation. Phenotypic expression was also 2.3 to 2.6 times increased when 20 micrograms/ml of verapamil was present during calcium phosphate-mediated DNA transfection.

Animals↗
PubMed1983

Elemental composition of the dense bodies of rat platelets determined by electron probe x-ray microanalysis of freeze-substituted sections.

A semiquantitative x-ray microanalytical study was made of dense bodies in rat and human blood platelets prepared by freeze substitution. After the freeze substitution, electron dense bodies containing 5-hydroxytryptamine(5-HT) were well preserved. Electron probe x-ray microanalyses clearly defined species differences in the cations of dense bodies of rat and man. Direct calculation of elemental concentration ratios demonstrated a high level of Mg, with lesser amounts of K and Ca in rat, while there was a negligible level of Mg in man but a high amount of Ca. These results indicate that freeze-substitution is a suitable preparation for the study of diffusible electrolytes which may open the way to quantitative analysis using appropriate standards for analytical electron microscopy of resin sections.

Animals↗
PubMed1983

Dissociation of natural killer activity and antibody-dependent cellular cytotoxicity in spleen cells of tumor bearing mice.

Antibody-dependent cellular cytotoxicity (ADCC) increased with the development of tumors in C3H/He mice bearing spontaneous breast cancer or the syngeneic hepatoma MH-134 and in C57BL/6 mice bearing the syngeneic Lewis lung carcinoma 3LL. This cytotoxicity decreased after treatment with guinea pig, monoclonal IgM anti-Thy 1.2 serum and complement to the non-cancer level thus indicating that the increased ADCC in mice with cancer seems mainly attributable to cells with the Thy 1 antigen. On the other hand, NK activity decreased greatly when mice had tumors. Treatment with monoclonal IgM anti-Thy 1.2 serum and complement showed no significant influence on the natural killer (NK) activity of spleen cells of mice bearing MH-134 cancer, but in the 3LL-bearing mice the activity decreased significantly.

Animals↗
PubMed1983

Ossification of thoracic ligamenta flava.

Although ligamentum flavum ossification (LFO) often occurs in normal persons, there are no reports of its detection on lateral chest radiographs made during screening examinations. Review of 1,744 consecutive lateral chest radiographs identified LFO in 6.2% of males and 4.8% of females. LFO occurred mainly at the intervertebral segments from T9-T10 through T12-L1. Most prevalent was the hook-shaped LFO, protruding inferiorly from the inferior facets into the projections of the intervertebral foramina. Though LFO can cause severe neurologic symptoms, none of the affected persons in this study reported such symptoms. LFO was first visualized radiographically when the subjects were 20-40 years old, and it may be a physiologic condition. The LFO in these cases existed independent of thoracic posterior longitudinal ligament ossification, diffuse idiopathic skeletal hyperostosis, and degenerative osteoarthritis.

Adult↗
PubMed1983

Milbemycins, a new family of macrolide antibiotics. Fermentation, isolation and physico-chemical properties of milbemycins D, E, F, G, and H.

Strain Au-3, a mutant of Streptomyces hygroscopicus subsp. aureolacrimosus, obtained with ultraviolet irradiation, was a high-yield strain of milbemycins D, E, F, G and H. Fermentation studies on the strains were conducted in shake flasks and 30-liter jar fermentors. Isolation of the metabolites was performed by adsorption on resinous adsorbent followed by elution with aqueous MeOH and separated by silica gel column chromatography. Milbemycin D was obtained as colorless needles after recrystallization and milbemycins E, F, G and H were purified to homogeneity by column chromatography. Physico-chemical characterization revealed that milbemycins D, E, F, G and H were new antibiotics possessing the 16-membered macrocyclic lactone with a 6,6-membered spiroketal ring system.

Anti-Bacterial Agents↗
PubMed1983

Milbemycins, a new family of macrolide antibiotics. Fermentation, isolation, physico-chemical properties and bioconversion of milbemycins J and K.

Strain Rf-107, a mutant of Streptomyces hygroscopicus subsp. aureolacrimosus, obtained with ultraviolet irradiation, produced two new macrolide antibiotics, milbemycins J and K without production of any of the other milbemycins described in the previous paper. Fermentation studies on the strain were conducted in shake flasks and 30-liter jar fermentors. Isolation of the antibiotics was performed by adsorption on resinous adsorbent followed by elution with aqueous MeOH. Purification of milbemycins J and K was completed with Lobar Si 60 column chromatography to give colorless crystals. Physico-chemical data, such as UV, IR and NMR spectra are described. Milbemycins J and K were readily converted by the intact cells of the parent strain to milbemycins alpha 1 and alpha 3, respectively. Physico-chemical characterization and the bioconversion studies revealed that milbemycins J and K were new antibiotics having the 16-membered macrocyclic lactone with a 6,6-membered spiroketal ring system.

Anti-Bacterial Agents↗
PubMed1983

Milbemycins, a new family of macrolide antibiotics. Structure determination of milbemycins D, E, F, G, H, J and K.

The milbemycins, a group of potent, broad-spectrum antiparasitic and pesticidal agents, are architecturally novel antibiotics of 16-membered macrocyclic lactone. Seven new milbemycin analogues designed as milbemycins D, E, F, G, H, J and K were isolated from the fermentation broth of the mutant strain of Streptomyces hygroscopicus subsp. aureolacrimosus. The structural determination of these new components was made mainly by comparing with mass spectra, and 1H and 13C NMR spectra of milbemycin alpha- and beta-series previously published from our laboratory. Milbemycins D, E, F, G and H have characteristically an isopropyl side chain at C-25 which differs from the known milbemycin family bearing methyl or ethyl group at C-25. Milbemycins J and K possess a ketone group at C-5 instead of a hydroxyl or methoxy group. Apart from X-ray crystallography, the R-configuration of the hydroxyl group at C-5 could be best explained both by application of CD allylic benzoate method to the n-N, N-dimethylaminobenzoate of milbemycin D and by comparison of the specific rotation of milbemycin D itself and its acetate with the epimeric isomers at C-5.

Anti-Bacterial Agents↗
PubMed1983

Milbemycins, a new family of macrolide antibiotics. Studies on the biosynthesis of milbemycins alpha 2, alpha 4 and D using 13C labeled precursors.

The biosynthetic origins of the carbon skeleton of milbemycins alpha 2, alpha 4 and D were studied. 13C Labeled antibiotics, milbemycins alpha 2, alpha 4 and D, were isolated from the culture broth of Streptomyces hygroscopicus subsp. aureolacrimosus strain Au-3 after feeding [1-13C]acetate, [1-13C]-propionate, [3-13C]propionate, [1-13C]isobutyrate, DL-[2-13C]valine and L-[methyl-13C]methionine, and 13C NMR spectra of the antibiotics thus obtained were measured. It was revealed that the carbon skeleton, except for carbon 25, of milbemycins alpha 2, alpha 4 and D are derived from seven acetate units and five propionate units. It was also shown that the methyl, ethyl and isopropyl groups at carbon 25 in milbemycins alpha 2, alpha 4 and D are derived from acetate, propionate and isobutyrate or DL-valine, respectively, and the methyl carbon of the methoxy group at carbon 5 in milbemycins alpha 2 and alpha 4 was enriched by L-[methyl-13C]methionine.

Acetates↗
PubMed1983

Isolation of chloroquine-resistant Chinese hamster V79 cell variants that are also resistant to ammonium chloride.

Chloroquine-resistant (CQr) clones (CQ-21 and CQ-22) have been isolated from mutagenized hamster lung V79 cells by exposing the cells to a high dose of chloroquine. CQ-21 and CQ-22 showed about 3-fold higher resistance to chloroquine than the parental V79 cells, and they showed specific cross-resistance to another amine, NH4Cl, which is also concentrated in lysosomes. CQr clone showed no cross-resistance to other unrelated agents. Chloroquine-induced inhibition of [125I]ricin internalization was observed in both cell lines at neutral pH, but the inhibition of uptake was less in the variant. Also, the degradation of endogenous protein was slowed in the mutant; further, treatment of cells with 30 micrograms/ml of chloroquine inhibited the degradation of endogenous proteins in the parental V79, but not in CQ-22 cells. Similar levels of acid phosphatase, beta-glucuronidase and cathepsin D were observed in V79 and CQ-22 cells, but the level of cathepsin B was lower in the mutant. Electron microscopy showed an increased number of electron-dense bodies, possibly autophagosomes/lysosomes, in the mutant cells grown for 4 days with 5 micrograms/ml of chloroquine. Similar aberrant structures were observed in the parental V79 cells treated for only 3 h with 5 micrograms/ml of chloroquine.

Ammonium Chloride↗