In vitro antibacterial activities of a new cephalosporin, ceftriaxone, were bacteriologically characterized in comparison with those of cefotaxime and ceftizoxime. Minimal inhibitory concentrations (MIC) of cefriaxone determined on 680 fresh clinical isolates in Japan showed extraordinarily high activity against all gram-negative bacteria. Especially notable was its high activity against Proteeae species and Haemophilus influenzae ; in this respect it was greatly superior to both cefotaxime and ceftizoxime. It also showed high activity against Pseudomonas aeruginosa and some anaerobic pathogens. Against other strains, in general ceftriaxone exhibited activity comparable to those of 2 structurally related cephalosporins, except for Klebsiella sp. and Pseudomonas maltophilia, against which it showed lower activity. Its activity is bactericidal and, in contrast to cefotaxime and ceftizoxime, its minimal bactericidal concentration (MBC) value was less than 3 times the MIC except for Ps. aeruginosa. Its mode of action was morphologically assessed. Ceftriaxone showed an unusually high stability to most bacterial β-lactamases except to so-called cefuroximases from Bacteroides fragilis, Pseudomonas cepacia and Proteus vulgaris. In addition, ceftriaxone was found to be a very potent inhibitor of cephaloridine hydrolysis by various β-lactamases.
5'-Deoxy-5-fluorouridine (5'-DFUR) was parenterally and orally effective on various transplantable tumors and its activity was better than that of other fluorinated pyrimidines. However, like 5-fluorouracil and 2'-deoxy-5-fluorouridine (FUdR), 5'-DFUR was ineffective on L1210 leukemia resistant to 5-fluorouracil, suggesting that it would exert its antitumor activity through converted 5-fluorouracil. In tissue culture, 5'-DFUR inhibited the growth of various tumor cells similarly to ther fluorinated pyrimidines. However, 5'-DFUR was unique in that uridine completely reversed its inhibitory effect. Enzymological study clarified that uridine inhibited the conversion of 5'-DFUR to 5-fluorouracil by a uridine phosphorylase, in parallel to its reverse effect on cell growth inhibition by 5'-DFUR. Furthermore, a subline of L1210 leukemia resistant to 5'-DFUR but not to 5-fluorouracil was found to lack the uridine phosphorylase. These results indicate that 5'-DFUR is a depot form of 5-fluorouracil which can be promptly activated by uridine phosphorylase. In addition, the uridine phosphorylase was found to be abundant in sarcoma-180 solid tumor, leading to a significantly higher concentration of converted 5-fluorouracil in this tumor than in other normal tissues. This provides a good explanation for the high chemotherapeutic index of 5'-DFUR against this tumor, which may be applicable also for other tumors.
A substance inhibiting Escherichia coli motility was isolated by “motilometry” assay from the culture broth of Streptomyces sp. strain NR9GG8 and was found to be identical with desferrioxamine B. Its inhibitory effect was reversed by cyclic adenosine 3′,5′-monophosphate (cAMP), while the motility stimulation by cAMP was diminished by this inhibitor. Its effects on various enzymes involved in cAMP metabolism of function of cAMP were examined.
A novel direct calculation method of response matrices on heterogeneous lattices by using the Monte Carlo method is proposed. These direct response matrices (DRMs) can be used in core calculations in place of the conventional homogenized lattice constants. The DRMs are formalized by four sub response matrices (sub-RMs) in order to respond to a core eigenvalue, k; thus the DRMs can be re-evaluated on each outer iteration in the core calculations. The sub-RMs can be evaluated by analyzing each neutron's trajectory from ordinary lattice calculations with the Monte Carlo code. Since these sub-RMs are calculated directly under an actual complex assembly geometry, i.e., without a homogenization process, intra-assembly heterogeneous effects can be reflected on global partial current balance calculations. With using two of the sub-RMs, which deal with neutron production probabilities for each fuel pin, and the obtained partial current balance, pin-wise neutron production distributions can also be reconstructed. The DRM method is applied to infinite lattice calculations and multi-assembly calculations. As a result, it is shown that the derivation of the method is valid and intra-assembly heterogeneity is reflected in the results correctly.
Implantable medical devices need to transmit information between the inside and the outside of a human body. Therefore, sufficient information needs to traverse a long communication distance but at low power. However, electromagnetic waves attenuate when information is transmitted through tissues such as muscle, skin, and various organs. In this paper, we propose a new method for wireless information transmission that uses whole-body resonance. First, we constructed a cylindrical human body model (170 mm high). Electromagnetic simulation was provided by a small implanted dipole antenna. We then examined the maximum frequency values, taking the electric and magnetic fields surrounding the human body model and dividing by the transmitting power of the antenna. The maximum frequency value was 43 MHz, which was essentially the same frequency as the theoretical value of whole-body resonance (44.1 MHz). Therefore, information may possibly transmit more efficiently using whole-body resonance.
Journal Article Ribosome Degradation and Degradation Products in Starved Escherichia coli: VI. Prolonged Culture during Glucose Starvation Get access Shoji OKAMURA, Shoji OKAMURA The Institute of Applied Microbiology, University of TokyoHongo, Bunkyo-ku, Tokyo Search for other works by this author on: Oxford Academic PubMed Google Scholar Hiromi B. MARUYAMA, Hiromi B. MARUYAMA The Institute of Applied Microbiology, University of TokyoHongo, Bunkyo-ku, Tokyo Search for other works by this author on: Oxford Academic PubMed Google Scholar Tomomichi YANAGITA Tomomichi YANAGITA The Institute of Applied Microbiology, University of TokyoHongo, Bunkyo-ku, Tokyo Search for other works by this author on: Oxford Academic PubMed Google Scholar The Journal of Biochemistry, Volume 73, Issue 5, May 1973, Pages 915–922, https://doi.org/10.1093/oxfordjournals.jbchem.a130174 Published: 01 May 1973 Article history Received: 27 May 1972 Published: 01 May 1973
