Yutaka Tajima

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The in vitro antibacterial effect of the combination of various polyoxometalates with beta-lactam antibiotics on methicillin-resistant Staphylococcus aureus (MRSA) strains is investigated by the use of both the National Committee for Clinical Laboratory Standards (NCCLS) disk method and the agar dilution method. Keggin-structural polyoxotungstates such as(More)
Although tungsten is an important material in some industrial and chemical processes, the biological and biochemical effects, including the toxicity, of tungsten compounds are not known well. In this study, a reporter gene assay using special strains of Escherichia coli was performed to investigate the mode of action of two polyoxotungstates, i.e.(More)
In our continuous work on the enhancement of the antibacterial activity of beta-lactam antibiotics against the cells of methicillin-resistant Staphylococcus aureus (MRSA) strains by Keggin-structural polyoxotungstates and their lacunary species, Wells-Dawson, double-Keggin, and Keggin-sandwich polyoxotungstates are also found to be synergistic but highly(More)
  • Yutaka Tajima
  • Rinsho byori. The Japanese journal of clinical…
  • 2002
Previously, a factor (Factor T) was found in aged mixtures of tungstate and phosphate, which greatly sensitizes strains of methicillin-resistant Staphylococcus aureus to beta-lactams. Factor T was purified and identified as undecatungstophosphate([PW11O39]7-). Undecatungstosilicate([SiW11O39]8-), a compound closely related to undecatungstophosphate, showed(More)
  • Y Tajima
  • The Journal of antimicrobial chemotherapy
  • 1997
A new 'drug efficacy score' was devised to compare the in-vitro efficacy of various drugs. The score is easily calculated from an MIC correlogram; strains positioned above the diagonal of the correlogram are positively scored and those positioned below are given negative scores. Each score is multiplied by the number of corresponding strains, and all such(More)