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Biomedical subjects

S Mizuno

Publications and source records attributed to S Mizuno.

At least 595 records · Page 33Linked to original sources
PubMed1980

Studies on the cross-resistance of Mycobacterium tuberculosis, strain H37Rv, to aminoglycoside- and peptide-antibiotics.

Various phenotypes of the resistance to aminoglycoside- and peptide-antibodies of Mycobacterium tuberculosis strain H37Rv were produced by single- and/or two-step selection of the parent strain. Mutants obtained by single-step selection with antibiotics were classified into ten phenotypes; one of single resistance, two of triple resistance, three of quadruple resistance, and four of sextuple resistance. There were two kinds of sextuple resistance (high resistance to enviomycin, viomycin, capreomycin, kanamycin, lividomycin). One was isolated from the parent strain by single-step selection and could be eliminated by mutation to isoniazid resistance, the other was obtained by two-step selections and was not eliminated by mutation to isoniazid resistance. Interaction between mutation to streptomycin resistance and mutation to quadruple resistance (4R phenotype) was observed. Streptomycin resistance interfered with the formation of the 4R phenotype and produced a different phenotype, KR instead of the 4R phenotype. The existence of mutation of the 4R phenotype did not usually interfere with mutation to streptomycin resistance, but a small portion of the mutants with the 4R phenotype were altered in their phenotype from 4R to KR after addition of the mutation to streptomycin resistance. This effect of the mutation to streptomycin resistance was not observed in mutants which already had a mutation to klR phenotype (mutation to low concentrations of kanamycin only).

Aminoglycosides↗
PubMed1980

Synergistic cell killing by antitumor agents and hyperthermia in cultured cells.

The effects of treatment with several antitumor agents in combination with hyperthermia (42 degrees and 43 degrees) on the cell survival of cultured mouse leukemia L5178Y and mammary carcinoma FM3A cells were studied by following clonal growth in a soft-agar medium. L5178Y cells were more heat-sensitive than FM3A cells. The cytotoxicity of bleomycin was markedly increased when the cells were treated with the drug in combination with hyperthermia or were preheated prior to drug treatment. The sensitization of FM3A cells to bleomycin was much more pronounced at 43 degrees than 42 degrees. The action of adriamycin was also potentiated at the elevated temperatures, but that of daunomycin was not. The sensitization of FM3A cells to adriamycin at 43 degrees, however, was limited to short times of heat exposure; the cells becoming resistant to further killing by adriamycin after heat exposure times of more than 30 min. The two cell lines were resistant to the cytotoxic action of low concentrations of aclacinomycin A at 37 degrees, but they became sensitized at 42 degrees and 43 degrees. The cytotoxicity of actinomycin D was also markedly potentiated at 42 degrees. The cytotoxic effects of mitomycin C, neocarzinostatin, carboquone and 1-(4-amino-2-methylpyrimidine-5-yl)-methyl-3-(2-chloroethyl)-3-nitrosourea (ACNU) were also appreciably potentiated at 42 degrees but those of cytosine arabinoside, 5-fluorouracil and vincristine were not.

Animals↗
PubMed1979

Estrogen withdrawal in chick oviduct. Evidence for continued expression of active unique genes using an "expressed" DNA probe.

We have analyzed the effect of estrogen on the kinds of unique DNA sequences which are transcriptionally expressed in chick oviduct with an "expressed" DNA probe. Steady-state nRNA in estrogen-stimulated chick oviduct represents about 25% of the complexity of total chick unique DNA. To purify this expressed DNA fraction, chick unique DNA was isolated, nick-translated, and hybridized to chemically mercurated oviduct nRNA (Hg-nRNA); the resulting hybrids were bound to sulfhydryl-Sepharose, and DNA was selectively recovered by thermal elution in formamide buffer. To compare the sequence homology between nRNAs isolated from oviduct before or up to 6 days after estrogen withdrawal, trace amounts of expressed DNA derived from estrogen-stimulated oviduct were hybridized in RNA-excess reactions. All nRNAs hybridized with equal efficiency. Furthermore, hybridization of expressed DNA to nRNA mixtures showed that nRNA from nonwithdrawn and withdrawn oviduct contained a similar set of unique sequences. The data indicate that, at most, only a small percentage (0--5%) of transcriptionally active unique DNA sequences are shut down when estrogen is removed from the circulation.

Animals↗