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Biomedical subjects

S Mitsuhashi

Publications and source records attributed to S Mitsuhashi.

At least 127 records · Page 7Linked to original sources
PubMed1988

Outer membrane permeation of Bacteroides fragilis by cephalosporins.

Outer membrane permeation of Bacteroides fragilis by cephalosporins was examined by a previously described method. The permeation parameters of cephalosporins in B. fragilis were close to 10(-5) cm3/min per microgram of cell dry weight. These values were about an order of magnitude lower than those in Escherichia coli. In B. fragilis, the permeation was not directly proportional to the hydrophilicity of cephalosporins, and the ion selectivity was weak.

Bacterial Outer Membrane Proteins↗
PubMed1988

In vitro and in vivo antibacterial activities of ME1207, a new oral cephalosporin.

ME1207 (pivaloyloxymethyl ester of ME1206) is a new oral cephalosporin. ME1206 is (6R,7R)-7-[(Z)-2-(2-aminothiazol-4-yl)-2-(methoxyimino)- acetamido]-3-[(Z)-2-(4-methylthiazol-5-yl)-ethyl]-cephem-4-carboxy lic acid. The susceptibilities of about 1,600 clinical isolates to ME1206 were determined by the agar dilution method. ME1206 showed a broad spectrum of activity against gram-positive and gram-negative bacteria. ME1206 was more active than cefaclor, T-2525, and cefixime against Staphylococcus aureus and Staphylococcus epidermidis. Against gram-negative bacteria, the activity of ME1206 was comparable with that of T-2525, but ME1206 was less active than cefixime. Against Streptococcus pneumoniae, Haemophilus influenzae, and Neisseria gonorrhoeae, ME1206 had high activity (MIC, less than or equal to 0.05 microgram/ml). ME1206 was stable against various beta-lactamases, except beta-lactamases from Providencia rettgeri, Pseudomonas cepacia, and Escherichia coli W3630 (Rms213). The 50% effective doses of ME1207 after oral administration against systemic infections in mice were comparable with those of T-2588 against gram-negative bacteria and about one-fourth that of T-2588 against Staphylococcus aureus Smith.

Administration, Oral↗
PubMed1988

Properties of a broad spectrum beta-lactamase isolated from Flavobacterium meningosepticum GN14059.

A broad substrate-spectrum beta-lactamase was purified from Flavobacterium meningosepticum GN14059. The purified enzyme gave a single protein band on SDS-polyacrylamide gel electrophoresis. The molecular weight was estimated to be about 30,000 and the isoelectric point was 5.1. The enzyme hydrolyzed various beta-lactam antibiotics including oxyiminocephalosporins and aztreonam. Relative rates, with cephaloridine as 100, were cephalothin 200, cefazolin 48, cefuroxime 153, cefotaxime 51, ceftazidime 20, ampicillin 26, carbenicillin 19, and aztreonam 20. The enzyme activity was inhibited by clavulanic acid, sulbactam, imipenem and cephamycins.

Anti-Bacterial Agents↗
PubMed1988

Cephalosporinase interactions and antimicrobial activity of BMY-28142, ceftazidime and cefotaxime.

Cephalosporinases of Enterobacter cloacae and Citrobacter freundii were responsible for resistance to newer cephalosporins such as cefotaxime and ceftazidime but not BMY-28142. Interaction of these cephalosporins including hydrolysis, binding, inhibition, and inactivation with cephalosporinases from E. cloacae GN7471 and C. freundii GN7391 were studied. BMY-28142 was much more stable against the both enzymes than cephalothin, but more hydrolyzable than cefotaxime and ceftazidime at higher concentration such as 100 microM. Because of low affinity for the enzymes, i.e. large Km and Ki, the calculated hydrolysis rate of BMY-28142 at 0.1 microM was smaller than those of cefotaxime and ceftazidime, that explained the difference in activity against cephalosporinase-producing strains between BMY-28142 and cefotaxime or ceftazidime. The effects of cephalosporinase production on susceptibility of Escherichia coli omp mutants were examined using a plasmid having cephalosporinase gene of C. freundii GN346. Decrease in susceptibility of E. coli by cephalosporinase production was larger in the strain lacking outer membrane proteins (Omp) F and C, and smaller in the strain producing OmpF constitutively.

Cefepime↗
PubMed1988

[Recurrence of upper urinary tract calculi].

Treatment of upper urinary tract stones has changed greatly. The recurrence of calculi after the discharge was studied in the 634 patients with urolithiasis admitted to our department during the 9 years up to the end of 1984. The recurrence rate in the 325 cases followed for more than 3 months after the disappearance of the original stones, was 15.6% after 2 years, 27.6% after 5 year and 51.4% after 8 years. In recurrent stone formers, the rate of recurrence thereafter was greater than that of primary stone formers. The growth of calculi was rapid in the renal stone former concomitant with urinary tract infection together with a past history of renal surgery. In relation to the composition of the stone, uric acid calculi tended to recur more often than calculi composed of other substances. In view of recurrence, pyelolithotomy is preferred to renal parenchymal incision.

Adolescent↗
PubMed1987

[Effect of oral administration of L-dopa on the plasma levels of growth hormone-releasing hormone (GHRH) in normal subjects and patients with various endocrine and metabolic diseases].

The responses of plasma growth hormone-releasing hormone (GHRH) and growth hormone (GH) to oral administration of L-dopa were studied in normal subjects and patients with various endocrine and metabolic diseases to clarify the pathophysiological role of the GHRH-GH axis. In normal subjects, the plasma GHRH concentration was increased from the basal value of 9.8 +/- 1.4 pg/ml (mean +/- SE) to 34.8 +/- 3.1 pg/ml at 30 approximately 90 min after oral administration of 500 mg L-dopa, followed by a rise of GH release (plasma GH level from less than 1 ng/ml to 21.7 +/- 4.7 ng/ml) in most cases, indicating that L-dopa stimulates GH secretion via hypothalamic GHRH. On L-dopa administration, no apparent increases in both plasma GHRH and GH concentrations were observed in patients with hypothalamic hypopituitarism, whereas GHRH administration induced almost normal GH response. In patients with acromegaly, the plasma levels of GHRH remained stationary after the L-dopa administration and did not correlate with plasma GH levels. In subjects with simple obesity, the responses of plasma GHRH (peak 13.2 +/- 1.2 pg/ml) and GH (peak 4.3 +/- 1.7 ng/ml) to L-dopa were significantly lower than those in normal subjects (p less than 0.01). In patients with primary hypothyroidism, peak levels of plasma GHRH (12.6 +/- 1.3 pg/ml) and GH (2.4 +/- 0.6 ng/ml) were significantly lower than those in normal subjects (p less than 0.01). In patients with non-insulin dependent diabetes mellitus (NIDDM), the responses of GHRH and GH were divided into 2 groups; in the responder the peak values of GHRH and GH were 19.4 +/- 8.6 pg/ml and 12.2 +/- 1.4 ng/ml and in the low or non responder 14.7 +/- 1.5 pg/ml and 2.0 +/- 0.6 ng/ml, respectively. Between both groups, there was a significant difference in the values of fasting blood sugar and HbA1 and mean suffering period. These findings suggest that GH secretion evoked by the L-dopa administration is induced by GHRH released from the hypothalamus, and impairment of GH secretion associated with simple obesity, primary hypothyroidism, or NIDDM may be in part attributed to insufficiency of GHRH release from the hypothalamus, and indicate that L-dopa test is clinically useful for evaluating the ability of intrinsic GHRH release in such diseased states.

Adolescent↗
PubMed1987

In vitro activity and beta-lactamase stability of the oral cephalosporin BMY-28100.

BMY-28100 was compared with cephalexin, cefaclor, cefixime, and cefteram and found to be more active than the reference cephalosporins against Staphylococcus aureus, Staphylococcus epidermidis, Streptococcus faecalis, and Clostridium difficile. BMY-28100 was the next most active, after cefteram, against Streptococcus pyogenes and Streptococcus pneumoniae. Against gram-negative bacteria, BMY-28100 showed similar activity to that of cefaclor. The antimicrobial activity of BMY-28100, including bactericidal activity, against Staphylococcus aureus was less affected by penicillinase-production than was that of cefaclor. BMY-28100 was more stable than cefaclor against various types of penicillinases, especially against the penicillinase from Staphylococcus aureus.

Cefaclor↗
PubMed1987

Cloning and expression of the gene(s) for chromosome-mediated beta-lactamase production of Proteus vulgaris in Escherichia coli.

The gene(s) for chromosome-mediated beta-lactamase production of Proteus vulgaris GN7919 was cloned into a unique EcoRI site of pACYC184 as an insert of a 14.2-kb fragment, which was further digested into two fragments with EcoRI, 4.9 and 9.3 kb. The restriction enzyme digestion pattern of the recombinant plasmid, designated pMS182, had no similarity to those of other chromosomal beta-lactamase genes cloned from gram-negative bacteria. Plasmid pMS182 enabled host Escherichia coli ML4953 to inducibly produce beta-lactamase which was identical to that of the parent P. vulgaris in substrate profile, molecular weight, and reactivity to antiserum raised against P. vulgaris GN7919 beta-lactamase. The pMS182-harboring E. coli were highly resistant to beta-lactam antibiotics, possibly based on inducible production of beta-lactamase.

Chromosomes, Bacterial↗
PubMed1987

Structure-activity relations of 4-fluoromethyl monobactams.

New monobactam compounds with fluoromethyl side chains at the 4-position were synthesized. These compounds showed strong antibacterial activity against Gram-negative bacteria including Pseudomonas aeruginosa and good stability to various beta-lactamases. The effect of replacement of the 1-carboxy-1-methylethoxyimino residue of aztreonam with various substituted groups, and of the configuration of the 3- and 4-position were examined. Substitution of a carboxycyclopropoxy group in the oxyimino moiety effected the most potent antibacterial activity. The cis congeners were not hydrolysed by any types of beta-lactamases including the oxyiminocephalosporin hydrolysing enzyme. Introduction of a fluorine atom in the methyl group at the 4-position increased the beta-lactamase stability of monobactams.

Bacteria↗
PubMed1987

Immunological properties of a penicillinase produced by Alcaligenes denitrificans subsp. xylosoxydans.

Rabbit antiserum was prepared to the penicillinase of Alcaligenes denitrificans subsp. xylosoxydans GN14062. The antibody gave a single precipitin line in double immunodiffusion assays with the penicillinases from strain GN14062 and from two other A. denitrificans subsp. xylosoxydans strains. The precipitin line given by the GN14062 enzyme gave a reaction of complete identity with the precipitin lines of the penicillinases from the other A. denitrificans subsp. xylosoxydans strains. Furthermore, activity of the penicillinases from all three A. dentrificans subsp. xylosoxydans strains was neutralized by the antiserum to the GN14062 enzyme. Thus it was proved that the penicillinases produced by the three A. denitrificans subsp. xylosoxydans strains were immunologically identical. Penicillinases types I, II, III, IV, V, SHV-1, TEM-1, TEM-2, and the chromosomal penicillinases of Klebsiella pneumoniae GN69 and A. faecalis GN14061 formed no immunoprecipitate with, nor were neutralized by, the antiserum to the GN14062 enzyme. From these results, it was concluded that the penicillinase produced by A. denitrificans subsp. xylosoxydans was immunologically distinct from the penicillinases produced by these other bacteria.

Alcaligenes↗
PubMed1987

Norfloxacin resistance in a clinical isolate of Escherichia coli.

Analysis of DNA gyrase supercoiling and of norfloxacin uptake in Escherichia coli GN14176, a moderately norfloxacin-resistant clinical isolate, indicated that resistance was associated with both an altered drug target and a reduction in drug uptake.

DNA Topoisomerases, Type II↗
PubMed1987

Mutations producing resistance to norfloxacin in Pseudomonas aeruginosa.

Two genetically distinct classes of norfloxacin-resistant Pseudomonas aeruginosa PAO4009 mutants were isolated spontaneously. Two norfloxacin resistance genes, nfxA and nfxB, were mapped hex-9001 and leu-9005 and between pro-9031 and ilv-9023, respectively, on the P. aeruginosa PAO chromosome. The nfxA gene was shown to be an allele of nalA by transductional analysis with bacteriophage F116L. The nfxB mutant showed a 16-fold increase in resistance to norfloxacin and a slight increase in resistance to nalidixic acid. The nfxB mutant was unique in that it showed hypersusceptibility to beta-lactam and aminoglycoside antibiotics. This mutant had about a threefold-lower rate of norfloxacin uptake than that of the wild-type strain or nfxA mutant. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis of outer membrane proteins demonstrated the appearance of a 54,000-dalton protein in the nfxB mutant. These findings suggested that the norfloxacin resistance mechanism in the nfxB mutant might be an alteration in outer membrane permeability to norfloxacin.

Aminoglycosides↗
PubMed1987

In vitro and in vivo activity of NY-198, a new difluorinated quinolone.

NY-198 [1-ethyl-6,8-difluoro-1,4-dihydro-7-(3-methyl-1-piperazinyl)-4-oxo-3- quinolinecarboxylic acid hydrochloride] is a new difluorinated quinolone characterized by the presence of a C-methyl group at the 3 position of the piperazine moiety. It has a broad antibacterial spectrum. The in vitro antibacterial activity of NY-198 was almost the same as those of ofloxacin and norfloxacin, but far exceeded that of pipemidic acid. NY-198 was more active than norfloxacin against Pseudomonas maltophilia, Acinetobacter calcoaceticus, and anaerobic microorganisms. Cross resistance was not observed between NY-198 and various antibiotics including methicillin, gentamicin, and ampicillin. NY-198 had bactericidal activity at the MIC or slightly higher than the MIC. It showed excellent antibacterial activity against various systemic infections in mice. After oral administration, NY-198 was two times more active than or as active as ofloxacin and two to four times more active than norfloxacin.

Animals↗
PubMed1987

In vitro and in vivo antibacterial activities of CS-807, a new oral cephalosporin.

CS-807 is a new oral prodrug of R-3746, a cephalosporin derivative, with potent in vitro and in vivo antibacterial activity against both gram-positive and gram-negative bacteria. The susceptibility of about 1,200 clinical isolates to R-3746 was determined by the agar dilution method. Ninety percent or more of pathogens such as Staphylococcus aureus, streptococci, Escherichia coli, Klebsiella pneumoniae, Klebsiella oxytoca, indole-positive and indole-negative Proteus spp., Providencia rettgeri, and Haemophilus influenzae were inhibited at concentrations ranging less than or equal to 0.01 to 1.56 micrograms/ml. Furthermore, at a concentration of 3.13 micrograms/ml, 50% or more of Staphylococcus epidermidis, Morganella morganii, Citrobacter freundii, and Serratia marcescens strains were also inhibited. Pseudomonas aeruginosa and Xanthomonas maltophilia were resistant to R-3746. The activity of R-3746 was scarcely influenced by several growth conditions. R-3746 was highly resistant to hydrolysis by beta-lactamases derived from various species of bacteria. Killing-curve studies demonstrated bactericidal activity of R-3746 at concentrations above the MIC. R-3746 showed high affinity for penicillin-binding proteins 1, 3, and 4 of Staphylococcus aureus and 1A, 1Bs, and 3 of Escherichia coli. Systemic infections in mice caused by various pathogens, including beta-lactamase-producing strains, responded well to therapy with oral doses of CS-807.

Animals↗
PubMed1987

In vitro and in vivo antibacterial activities of T-2588, a new oral cephalosporin, compared with those of other oral beta-lactam antibiotics.

T-2588, the pivaloyloxymethyl ester of T-2525, [6R, 7R]-7-[(z)-2-(2-aminothiazol-4-yl)-2-methoxyiminoacetoamido] -3- [(5-methyl-2H-tetrazol-2-yl)methyl]-3-cephem-4-carboxylic acid, is a new oral cephalosporin. T-2525 had a widely expanded antibacterial spectrum against gram-negative and gram-positive bacteria. T-2525 was more active in vitro than cefaclor, cephalexin, and amoxicillin against members of the family Enterobacteriaceae and Branhamella catarrhalis. Moreover, it exhibited superior in vitro activity against Streptococcus pyogenes, Streptococcus pneumoniae, Haemophilus influenzae, and Neisseria gonorrhoeae. T-2525 was highly stable to various beta-lactamases, which were classified as Richmond and Sykes types Ia, Ib, Ic, III, IV, and Vc. It had high affinities for the lethal (essential) penicillin-binding proteins of Escherichia coli, Clostridium perfringens, and Bacteroides fragilis. T-2588 had excellent therapeutic effect on systemic infections in mice with various species of gram-negative bacteria, including beta-lactamase-producing bacteria.

Amoxicillin↗
PubMed1987

[Two cases of synchronous bilateral renal tumors].

Case 1: A 56-year-old man visited us complaining of gross hematuria. Because of his refusal to undergo a surgical operation, we performed embolization and chemotherapy, which were ineffective and he died of cancerous cachexia. Case 2: A 59-year-old female with microscopic hematuria was referred to our clinic. Left partial nephrectomy and right radical nephrectomy were done in a two-stage operation at a 3 month interval. She is now well without sign of recurrence at 9 months after the last operation.

Carcinoma, Renal Cell↗