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Biomedical subjects

S Mitsuhashi

Publications and source records attributed to S Mitsuhashi.

At least 199 records · Page 11Linked to original sources
PubMed1983

[Study of cefotaxime on stability to beta-lactamases and affinity to penicillin-binding proteins].

Cefotaxime (CTX) was compared with other cephems concerning stability to beta-lactamases and affinity to penicillin-binding proteins of Escherichia coli JE1011. The results are summarized as follows. 1. CTX showed potent activity against bacteria whose resistance is mediated by plasmids on chromosomal genes. 2. The antibacterial activity of CTX was not influenced by the transfer of 25 different plasmids to E. coli ML1410. 3. CTX was stable to typical cephalosporinases (CSases). This compound was slightly hydrolyzed by cefuroximases (CXases). 4. There was no difference between CTX and other cephems in the affinity to beta-lactamases. 5. CTX showed high affinity to the 1A, 1Bs and 3 fractions of penicillin-binding proteins of E. coli JE1011.

Bacteria↗
PubMed1982

Enhancing effects of mini-cells prepared from Salmonella typhimurium on anti-tumor immunity in sarcoma 180-bearing mice.

The enhancing effect of mini-cells of Salmonella typhimurium which do not contain chromosomal DNA on anti-tumor immunity in mice was studied. The growth of sarcoma 180 cells which were subcutaneously transplanted into ICR mice was significantly retarded in mice treated with Salmonella mini-cells at the same time or 7 days after S180 transplantation, while no or only a little growth inhibition was observed in mice treated 7 days prior to S180 transplantation. Treatment with mini-cells inoculation alone did not increase the survival time of mice that had received intraperitoneal transplants of S180 cells. However, a statistically significant increase of survival time was observed in mice treated with a combination of mini-cells and surgical resection of subcutaneous tumors when S180 cells were injected 7 days after the surgical resection. The injection of mini-cells restored macrophage chemotaxis in S180-bearing mice in which macrophage chemotaxis was greatly retarded but lymphocyte activity was not.

Animals↗
PubMed1982

Purine metabolic enzymes in lymphocytes. I. Adenosine deaminase and purine nucleoside phosphorylase activities in mouse lymphocyte subpopulations.

The distribution of adenosine deaminase (ADA) and purine nucleoside phosphorylase (PNP) activities in lymphoid organs and lymphocyte subpopulations in mice, and the effect of phytohemagglutinin P (PHA-P) and concanavalin A (Con A) on the enzyme activities were studied. ADA activity was distributed equally in cells from all organs used and no mouse strain differences were observed. In contrast, PNP activity varied with the mouse strain, being highest in C57BL/6 mice and lowest in BALB/c mice, and with the organ in ICR mice, being high in peripheral blood lymphocytes and spleen lymphocytes, low in mesenteric lymph node cells and absent or very weak in thymus cells. T and B lymphocytes were prepared from spleen of ICR mice. High ADA activity was found in both T and B lymphocytes, whereas PNP activity in the T lymphocytes was about one-third of that in the B lymphocytes. PNP activity in thymus cells was increased to the normal level of T lymphocytes in the spleens by cultivation without stimulant. The development of PNP activity in thymus cells was partially inhibited by Con A but was not affected by PHA-P. ADA activity in thymus cells was enhanced by in vitro stimulation with PHA-P but not with Con A. In contrast, in spleen lymphocytes the development of ADA activity was enhanced by stimulation with PHA-P and Con A, and that of PNP activity was enhanced by PHA-P but not by Con A.

Adenosine Deaminase↗
PubMed1982

Purine metabolic enzymes in lymphocytes. II. Adenosine deaminase and purine nucleoside phosphorylase activities in the immune response.

ICR mice were immunized with sheep red blood cells (sRBC). Both adenosine deaminase (ADA) and purine nucleoside phosphorylase (PNP) activities in spleen lymphocytes increased faster than the serum antibody titer and reached a peak one week after the immunization. ADA activity increased significantly in T lymphocytes but not in B lymphocytes collected from the spleens of the immunized mice. A statistically significant increase in PNP activity was found in both T and B lymphocytes from the spleens of the immunized mice. Spleen lymphocytes collected from ICR mice which had been immunized with mitomycin C-treated sarcoma 180 (S180) cells one week earlier showed cytotoxic activity against viable S180 cells. Both ADA and PNP activities in spleen lymphocytes of S180-immunized mice increased significantly, and both activities increased in T lymphocytes prepared from spleen of immunized mice. In contrast, an increase was found in PNP activity but not in ADA activity in B lymphocytes. These results suggest that an increase in both ADA and PNP activities may by necessary for the T-cell response in both humoral and cellular immune responses, and that an increase in PNP activity may be necessary for the B-cell response.

Adenosine Deaminase↗
PubMed1982

Conjugation of drug-resistance plasmids from vibrio anguillarum to Vibrio parahaemolyticus.

Drug-resistant strains of Vibrio anguillarum, a fish pathogen, were isolated from diseased fish in culture ponds. In investigations of these strains, the transfer of resistance to chloramphenicol, tetracycline, and sulfanilamide from multiple resistant organisms to laboratory recipients was observed. The plasmid from V. anguillarum was stably maintained in both recipient strains of Vibrio parahaemolyticus and Escherichia coli. The plasmids isolated from Vibrio anguillarum belong to incompatibility group C. The molecular weight of these plasmids determined by electron microscopic observation was about 103 to 113 megadaltons.

Chloramphenicol↗
PubMed1982

Antimicrobial and beta-lactamase inhibitory activities of carpetimycins A and B, new carbapenem antibiotics.

Carpetimycins A and B showed widely broad spectra and potent activity against gram-positive and gram-negative bacteria, including various species of anaerobic bacteria. The antimicrobial activity of carpetimycin A was 8 to 64 times greater than that of carpetimycin B and 4 to 128 times greater than that of cefoxitin. The inhibitory concentration of carpetimycin A required to inhibit more than 90% of clinical isolates was 0.39 micrograms/ml for Escherichia coli and klebsiella and 1.56 microgram/ml for Proteus and Staphylococcus aureus. At a concentration of 3.13 micrograms/ml, carpetimycin A inhibited almost all clinical isolates of Enterobacter and Citrobacter, which showed resistance to many clinically used beta-lactam antibiotics. Carpetimycins A and B furthermore were shown to have potent inhibitory activities against several kinds of beta-lactamases produced by beta-lactam-resistant strains; they inhibited not only penicillinase-type beta-lactamases but also cephalosporinase-type beta-lactamases, which were insensitive to clavulanic acid. In combination with beta-lactam antibiotics such as ampicillin, carbenicillin, and cefazolin, carpetimycins A and B showed synergistic activities against beta-lactam-resistant bacteria.

Animals↗
PubMed1982

In vitro antibacterial activity of E-0702, a new semisynthetic cephalosporin.

E-0702 is an antipseudomonal cephalosporin derivative which has a broad spectrum of antibacterial activity against clinical isolates of gram-positive and gram-negative bacteria. Its in vitro antibacterial activities were less than those of cefoperazone and cefotaxime against Staphylococcus aureus and Staphylococcus epidermidis, but were significantly high against gram-negative bacteria including the Pseudomonas group. It was most characteristic that E-0702 showed high antibacterial activity against Pseudomonas aeruginosa. E-0702 was relatively stable to inactivation by plasmid-mediated penicillinases and cephalosporinases produced by gram-negative bacteria.

Anti-Bacterial Agents↗
PubMed1982

Plasmid-mediated gentamicin resistance of Pseudomonas aeruginosa and its lack of expression in Escherichia coli.

We isolated 11 nonconjugative plasmids mediating resistance to aminoglycoside antibiotics, including gentamicin, from Pseudomonas aeruginosa strains. Their genetic properties were investigated in both P. aeruginosa and Escherichia coli transformants. The plasmid molecular weights ranged from 11 x 10(6) to 24 x 10(6). A low level or complete absence of gentamicin resistance was observed when these plasmids were introduced into E. coli, but gentamicin resistance was restored when the plasmids were transferred back to P. aeruginosa from E. coli. Aminoglycoside-modifying enzyme activity was detected in P. aeruginosa harboring these plasmids, but was absent or greatly reduced in E. coli strains. This lack of expression may explain the observed decrease in aminoglycoside resistance.

Aminoglycosides↗
PubMed1982

In vitro and in vivo activity of DL-8280, a new oxazine derivative.

DL-8280, 9-fluoro-3-methyl-10-(4-methyl-1-piperazinyl)-7-oxo-2,3-dihydro-7H- pyrido-(1,2,3-de)1,4-benzoxazine-6-carboxylic acid, is a new nalidixic acid analog with a broad spectrum of antibacterial activity against gram-negative and gram-positive bacteria, including obligate anaerobes. The activity of DL-8280 against Enterobacteriaceae, Pseudomonas aeruginosa, Haemophilus influenzae, Neisseria gonorrhoeae, and Clostridium perfringens was roughly comparable to that of norfloxacin and far exceeded that of pipemidic acid and nalidixic acid. DL-8280 had greater activity against Staphylococcus spp., Streptococcus spp., Pseudomonas maltophilia, Acinetobacter spp., and Bacteroides fragilis than did norfloxacin, pipemidic acid, and nalidixic acid. Nalidixic acid-resistant Enterobacteriaceae, ampicillin-resistant gonococci, and clindamycin-resistant obligate anaerobes were also susceptible to DL-8280. The activity of DL-8280 was affected very little by inoculum size, and its action was bactericidal at two times the minimal inhibitory concentrations at most. Administered orally to mice experimentally infected with Staphylococcus aureus, Streptococcus pyogenes, Escherichia coli, Proteus mirabilis, Serratia marcescens, or P. aeruginosa, DL-8280 was 2 to 7 times more effective than norfloxacin and 7 to more than 50 times more active than pipemidic acid.

Animals↗
PubMed1982

Purification and properties of inducible penicillin beta-lactamase isolated from Pseudomonas maltophilia.

Two types of beta-lactamase were found in the cell-free extract from Pseudomonas maltophilia GN12873. One was an inducible penicillin beta-lactamase, and the other was an inducible cephalosporin beta-lactamase. The purified penicillin beta-lactamase gave a single protein band on polyacrylamide gel electrophoresis. The isoelectric point was 6.9, and the approximate molecular weight was 118,000 by gel filtration and 26,000 by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, suggesting that this enzyme consisted of four subunits. For the hydrolysis of penicillin G, the optimal pH was 8.0 and the optimal temperature was 35 degrees C. The enzyme activity was inhibited by cephamycin derivatives, carpetimycins A and B, iodine, and HgCl2, but not by clavulanic acid. Furthermore, beta-lactamase activity was almost completely inhibited by EDTA but was recovered by the addition of zinc ion. The enzyme showed a unique substrate profile, hydrolyzing N-formimidoyl thienamycin at a significant rate.

Bacteria↗
PubMed1982

Properties of a new penicillinase type produced by Bacteroides fragilis.

A highly penicillin-resistant strain of Bacteroides fragilis, strain GN11499, was found among 80 clinical isolates of the B.fragilis group and appears to produce a new type of penicillinase. Penicillinase activity was detected in crude extracts and had a specific activity of 0.25 U/mg of protein. About 20% of the enzyme was released into the surrounding medium during growth. The enzyme hydrolyzed ampicillin and cloxacillin more rapidly than it did penicillin G, carbenicillin, and cephaloridine. Relative rates in a crude extract with penicillin G as 100 were ampicillin, 357; carbenicillin, 57; cloxacillin, 271; and cephaloridine, 71. Enzyme activity was inhibited by clavulanic acid, CP-45, 899, N-formimidoyl thienamycin, cefoxitin, moxalactam, and p-chloromercuribenzoate. The enzyme had a molecular weight of approximately 41,500 and an isoelectric point of 6.9. Penicillinase production and tetracycline resistance were transferred from B.fragilis GN11499 to two susceptible strains of B.fragilis and Bacteroides vulgatus by filter mating.

Bacterial Proteins↗
PubMed1982

Antibacterial activities of SM-1652 compared with those of other broad-spectrum cephalosporins.

The in vitro and in vivo activities of Sm-1652 were compared with those of other cephalosporins. SM-1652 possessed a wide antibacterial spectrum which included activity against Pseudomonas aeruginosa. It also exhibited potent antibacterial activities against gram-positive cocci and clinical isolates of glucose nonfermentative bacteria. Most notably, its activity against glucose nonfermentative bacteria was the highest of all of the drugs tested. The bactericidal activity of SM-1652 was compared with that of cefoperazone. The difference between the minimum bactericidal concentration and the minimum inhibitory concentration of SM-1652 was actually smaller than that of cefoperazone for Escherichia coli and clinical isolates of indole-positive Proteus spp. SM-1652 was stable for most cephalosporinases but was hydrolyzed to some extent by penicillinases. The in vivo therapeutic effect of SM-1652 against infections in mice was better than those of cefazolin and cefoxitin. The in vivo antipseudomonal activity of SM-1652 was second to that of cefsulodin.

Animals↗
PubMed1982

In vitro and in vivo antibacterial activity of T-1982, a new semisynthetic cephamycin antibiotic.

The activities of T-1982 (sodium 7 beta-[(2R, 3S)-2-(4-ethyl-2, 3-dioxo-1-piperazine-carboxamido)-3-hydroxybutanamido]-7 alpha-methoxy-3-[(1-methyl-1H-tetrazol-5-yl)thiomethyl]-3-cephem-4-carboxylate) against various gram-positive and gram-negative bacteria were compare with those of cefmetazole, cefoxitin, cefazolin, and cefoperazone. T-1982 was active against both gram-positive and gram-negative bacteria, including genera resistant to the other cephalosporins. T-1982 exhibited greater activity than did cefmetazole, cefoxitin, cefazolin, or cefoperazone against Escherichia coli, Klebsiella pneumoniae, Proteus mirabilis, and Serratia marcescens and was also highly active against Bacteroides fragilis. T-1982 was as stable to various beta-lactamases as were cefmetazole and cefoxitin. The therapeutic activities of T-1982 in mice experimentally infected with various gram-negative bacteria were superior to those of cefmetazole, cefoxitin, cefazolin, and cefoperazone.

Animals↗
PubMed1982

Transposition of the carbenicillin-hydrolyzing beta-lactamase gene.

We isolated a new transposon Tn2101, from plasmid Rms433 in Enterobacter cloacae. Tn2101 encoded the formation of type IV (carbenicillin-hydrolyzing) beta-lactamase and multiple resistance to streptomycin, sulfanilamide, spectinomycin, and mercury in addition to ampicillin. Tn2101 was transposable between conjugative (or nonconjugative) plasmids and the host chromosome. Transposition occurred independently of the general recombination ability of the host cell. Tn2101 had a molecular size of 9.5 x 10(6) and contained short inverted repeat terminal sequences.

Anti-Bacterial Agents↗
PubMed1982

Isolation and characterization of a streptomycin resistance plasmid from Pseudomonas cepacia.

A plasmid, Rms425, mediating resistance to streptomycin(Sm) and mercury(Hg) was isolated from Pseudomonas cepacia GN11131 of clinical origin. Rms425 was transferred to Pseudomonas cepacia, Pseudomonas aeruginosa and Escherichia coli strains by transformation with purified DNA and by conjugation between isogenic strains of P. aeruginosa or of E. coli by mixing on membrane filters. The molecular weight of Rms425 was estimated to be about 32 megadaltons by electron microscopy and it was classified as incompatibility group P. Examining the incorporation of [gamma-32P] or [8-14C] from isotope-labelled ATP into Sm using the cell-free extracts from P. cepacia or E. coli strains harboring Rms425, we found that the Sm resistance conferred by Rms425 was due to the phosphorylation of the drug.

Adenosine Triphosphate↗