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Biomedical subjects

M Fukunaga

Publications and source records attributed to M Fukunaga.

At least 433 records · Page 24Linked to original sources
PubMed1980

Co-mutagenic effects of propidium on petite induction by ethidium in Saccharomyces cerevisiae.

Propidium, whose structure is closely related to ethidium bromide, induced a low level of petites in yeast, but only at high concentrations with long incubation time, and only in growth medium. When added to growing cells, propidium also caused a large increase in petite induction by ethidium even at submutagenic concentrations of ethidium. Incorporation of adenine into DNA was inhibited by propidium in mitochondria but not in nuclei. Propidium by itself had no effects on fragmentation of pre-existing DNA, but enhanced mitochondrial DNA degradation provoked by ethidium. The proportion of suppressive clones occurring among the petites from ethidium treatment was reduced by the presence of propidium. All of these results indicated that propidium treatment led to degradation of the mitochondrial DNA in petites induced by ethidium but not in native (intact) mitochondrial DNA, nor in spontaneous petite colonies. The results are discussed in terms of possible mechanisms of modulation of petite induction.

Adenine↗
PubMed1980

Correlation between human erythrocyte aldehyde dehydrogenase activity and sensitivity to alcohol.

Young healthy Japanese men were given 0.48 g ethanol/kg body weight orally. Those responding with a marked increase in heart rate after alcohol also exhibited facial flushing and had higher acetaldehyde levels than those not responding, in spite of similar blood alcohol levels. The activity of aldehyde dehydrogenase in erythrocytes was found to correlate significantly (r=-0.73, p < 0.01) with the increase in heart rate after alcohol drinking. It is suggested that erythrocyte aldehyde dehydrogenase activity affects or reflects blood acetaldehyde levels and physiological response to alcohol, and may prove useful as a marker for alcohol sensitivity in Orientals.

Acetaldehyde↗
PubMed1980

Petite induction in Saccharomyces cerevisiae by ethidium analogs: distinction between resting and growing cells.

The importance of specific substituents, especially amino azide groups, for ethidium induction of petites was evaluated in resting and dividing cells of Saccharomyces cerevisiae through the study of a series of ethidium analogs. The structural requirements in resting and growing cells were found to be different, suggesting that at least two mechanisms are responsible for induction. The significance of particular substituents in the induction processes were recognized by: (1) a dependence upon the ethyl substituent at the ring nitrogen in both actively growing and in resting cells; and (2) the implication that amino substituents are important for the effect in dividing cells and especially in resting cells. Photolytic enhancement of petite induction (via a nitrene which forms a covalent linkage to a biological site) was observed for 3 of the azide analogs, which emphasizes the likelihood that metabolic activation of ethidium to a covalent complex is responsible for its effectiveness. Furthermore, these studies indicate that these monoazide analogs should be ideal probes for examining the mitochondrial mutagenic processes.

Ethidium↗
PubMed1980

[Enhancement of 67Ga tumor-to-blood ratios by chelating agent (author's transl)].

Chelating agent, such as CaEDTA, CaDTPA, D-penicillamine, DMSA, desferoxamine, NTA, cysteine ethyl ester, BAL, alpha-MPG, phthalein complexone, were tested as a possible contrast enhancing agent for tumor imaging with 67Ga-citrate. The intravenous administration of a chelating agent to Ehrlich's tumor bearing mice, one hour after the injection of 67Ga-citrate, accelerated the blood clearance with only a very slight change of activity in the target, increasing the tumor-to-blood ratio, and consequently achieving a better visualization. Among the tested chelating agents, D-penicillamine showed the highest target-to-nontarget ratio at a shorter time: a good tumor-to-blood ratio, performed after 24 hr with non-treated animals, was achieved in only 1-3 hr with post-treated animals. Thus, D-penicillamine hold a considerable promise as a contrast enhancing agent for future clinical use.

Animals↗
PubMed1980

[Emission CT].

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Carcinoma, Hepatocellular↗
PubMed1979

Intracellular binding of ethidium studied by photoaffinity labeling in vivo.

The azide analog of 14C-labeled ethidium bromide was mixed with yeast cells and when photolyzed by visible light, formed covalent complexes with all yeast cell organelles. The 14C counts were found in DNA, RNA and protein of yeast subcellular fractions, illustrating the complexity of binding of a drug which appears highly specific in its actions.

Affinity Labels↗