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Biomedical subjects

R Okachi

Publications and source records attributed to R Okachi.

At least 37 records · Page 2Linked to original sources
PubMed1983

[Bactericidal effects and combined action of micronomicin with beta-lactam antibiotics against Pseudomonas aeruginosa and Escherichia coli].

Micronomicin (MCR, sagamicin) exhibited bactericidal effects at the lowest concentration among the tested aminoglycoside antibiotics, those were all bactericidal at lower concentrations than that of cefoperazone. When MCR was combined with cefoperazone (CPZ) or piperacillin (PIPC), they showed synergistic activity on checker-board method against Pseudomonas aeruginosa, and they were also synergistic against Escherichia coli when MCR was combined with cefmetazole (CMZ) and cefoxitin (CFX). MCR was synergistic against 40.7% and 44.4% of clinically isolated P. aeruginosa at the fractionary inhibitory concentration (FIC) index 0.5 or less in combination with PIPC and CPZ, respectively. All of the remaining strains of P. aeruginosa were included in the partially synergistic range of FIC index 0.5 to 1. Between MCR and CFX or CMZ, synergy was observed against 63.0% and 88.9% of clinical isolates of E. coli at the FIC index less than 1. Combined effects of MCR and PIPC or CPZ were observed investigating the growing curve of P. aeruginosa, too.

Aminoglycosides↗
PubMed1983

[Therapeutic effects of micronomicin on experimental infections in mice by intravenous administration].

Protective effects of intravenous administration of micronomicin (MCR) on mouse experimental infections were investigated. Mice were better protected by intravenous administration in S. marcescens T-55 experimental infection than subcutaneous administration. No remarkable differences were found between the two administrations in cases of P. aeruginosa BMH No. 1 and E. coli GN 2411-5 infections. Intravenous administrations of MCR, gentamicin (GM), dibekacin (DKB), amikacin (AMK) and sisomicin (SISO) protected the infection of P. aeruginosa BMH No. 1 in a similar extent. MCR was more effective intravenously than AMK; DKB and AMK; DKB, AMK and SISO in experimental infections of E. coli GN 2411-5; S. marcescens T-55; P. aeruginosa KY-8510 harboring aminoglycoside inactivating enzyme AAC(6')-4, respectively.

Aminoglycosides↗
PubMed1983

[Inactivation of aminoglycoside antibiotics by clinically isolated Pseudomonas aeruginosa].

Minimal inhibitory concentrations (MIC) of micronomicin (MCR) and gentamicin (GM) against clinically isolated Pseudomonas aeruginosa F 4150 were 1.56 mcg/ml and 6.25 mcg/ml, respectively. Sisomicin, dibekacin, amikacin, netilmicin, tobramycin ribostamycin and kanamycin did not inhibit the strain at the concentrations less than 25 mcg/ml. Each aminoglycoside antibiotic was incubated in Tris-HCl buffer solutions (pH 7.8) containing cell free crude enzyme preparations obtained by sonic oscillation of intact cells of P. aeruginosa F 4150, coenzyme A and adenosine-5'-triphosphate. The residual activity at 3 hours of incubation at 37 degrees C was 88% for MCR and 33.6% for GM, while all of the other aminoglycoside antibiotics tested were completely inactivated under this condition.

Aminoglycosides↗
PubMed1983

[Combined effects of micronomicin and latamoxefi in vitro synergistic activities].

In vitro synergistic activities of new aminoglycoside antibiotic micronomicin (MCR, Sagamicin) combined with oxacephem antibiotic latamoxef (LMOX, Siomarin) were investigated. These antibiotics exhibited synergistic activities at FIC index lower than 0.5 against 20.8%, 32.7% and 1.9% of clinical isolates of Pseudomonas aeruginosa (48 strains), Serratia marcescens (52 strains) and Escherichia coli (54 strains), respectively. Partial synergism (0.5 less than FIC index less than 1) was observed in 79.2%, 55.8% and 31.5% of the same microorganisms, too. Each bacteriostatic concentrations of MCR and LMOX showed synergistically bactericidal effects when the drugs were administered at the same time against P. aeruginosa BMH No. 1, S. marcescens F-3283 and E. coli GN2411-5.

Aminoglycosides↗
PubMed1983

[Pharmacokinetic studies on micronomicin in rats. Comparison of intramuscular and drip intravenous administration models].

Absorption, tissue distribution and excretion of micronomicin (MCR) were studied in rats after intramuscular or 30 minutes drip intravenous administration (10 mg/kg). Serum levels of MCR were measured by bioassay, enzyme immunoassay and high pressure liquid chromatography. The pharmacokinetic studies of MCR after intramuscular or drip intravenous administration were carried out using one-compartment open model or two-compartment open model, respectively. Among 3 assay methods, similar pharmacokinetic parameters of MCR were obtained. In the simulation of serum levels of MCR, the differences between the measured and calculated serum levels after intramuscular or drip intravenous administration were less than 19% of the former levels. After intramuscular or drip intravenous administration of MCR, similar changes of the organ (kidneys, lungs, spleen and liver) levels were observed. Urinary recovery rates of MCR amounted to 82.3% or 91.6% by 24 hours after intramuscular or drip intravenous administration, respectively. After intramuscular or drip intravenous administration of MCR, no metabolites were found in urine of rats.

Aminoglycosides↗
PubMed1982

A new antibiotic echinosporin (XK-213) - producing organism, isolation and characterization.

Streptomyces echinosporus MK-213 produces a noval antibiotic echinosporin (XK-213). Isolation of echinosporin was performed by absorption on activated carbon under acidic conditions and then eluted by aqueous acetone. The compound crystallized from methanol is a water soluble white solid composed of C10H9NO5. Echinosporin exhibits weak antibacterial activities against Gram-positive and -negative microorganisms and its shows antitumor activity.

Animals↗
PubMed1979

Fortimicins C, D and KE, new aminoglycoside antibiotics.

From the fermentation broth of Micromonospora olivoasterospora CS-26 that produced fortimicins A and B three new aminoglycoside antibiotics, fortimicins C, D and KE, were isolated. Fortimicins C and D exhibited potent, broad spectrum antibacterial activities against Gram-positive and negative bacteria, while fortimicin KE was only weakly active.

Aminoglycosides↗
PubMed1977

Fortimicin A production by Micromonospora olivoasterospora in a chemically defined medium.

A chemically defined medium was devised in order to study the requirements for fortimicin A production by Micromonospora olivoasterospora KY 11515. Soluble starch was the best carbon source; NH4Cl and NH4NO3 were suitable nitrogen sources both for the growth and fortimicin production. Amino acids such as L-asparagine, L-aspartic acid and L-glutamic acid showed some stimulatory effects on both growth and antibiotic production of M. olivoasterospora while L-serine stimulated only antibiotic production and L-citrulline only the growth. K2HPO4, MgSO4.7H2O and CaCO3 were essential especially for the antibiotic production. The most important finding was that vitamin B12, cobalt and nickel showed marked stimulatory effects on fortimicin A production.

Amino Acids↗
PubMed1977

A new aminoglycoside antibiotic complex--the seldomycins. II. Isolation, physicochemical and chromatographic properties.

An antibiotic complex consisting of four components, seldomycin factors 1, 2, 3 and 5 was isolated from the fermentation broth of Streptomyces hofunensis sp. nov. by use of a cationic exchange resin. After silica gel column chromatography, the purified components were characterized as new aminoglycoside antibiotics by their physicochemical, chromatographic and antimicrobial properties.

Aminoglycosides↗
PubMed1977

Fortimicins A and B, new aminoglycoside antibiotics. I. Producing organism, fermentation and biological properties of fortimicins.

A culture of Micromonospora species MK-70 was found to produce two new antibiotics, fortimicins A and B. Antibacterial and paper chromatographic data on an eluate from IRC-50 treatment of fermentation beers indicated that fortimicins A and B are new antibiotics with broad-spectrum, basic and water-soluble properties. Fortimicin A exhibited potent, unique, broad-spectrum antibacterial activity against Gram-positive and negative bacteria both in vitro and in vivo, while fortimicin B was only weakly active.

Aminoglycosides↗
PubMed1977

Fortimicins A and B, new aminoglycoside antibiotics. II. Isolation, physico-chemical and chromatographic properties.

The aminoglycoside antibiotics fortimicins A and B produced by a naturally occurring strain Micromonospora sp. MK-70 were isolated from its fermentation beer. Fortimicins A and B were isolated as water-soluble, basic, white amorphous powders having molecular formula C17H35N5O6 and C15H32N4O5, respectively. Acid hydrolysis of fortimicin A indicated that it has one mole of glycine in its molecule while fortimicin B has not. Paper chromatography, silica-gel and carbon thin-layer chromatography revealed that fortimicins A and B are novel aminoglycoside antibiotics.

Aminoglycosides↗
PubMed1975

New antibiotic XK-62-2 (sagamicin). II Taxonomy of the producing organism, fermentative production and characterization of sagamicin.

Cultures of Micromonospora species, strains MK 65 and MK 62, were found to produce a new antibiotic XK-62-2 (Sagamicin). Antibacterial and paperchromatographic data on an eluate from IRC50 treatment of fermentation beers indicated that XK62-2 is a new antibiotic with broad spectrum, basic, and water-soluble properties, probably closely related to the gentamicin C group of antibiotics.

Anti-Bacterial Agents↗
PubMed1975

A new antibiotic victomycin (XK 49-1-B-2). II. Isolation, purification and physicochemical and biological properties.

A new antibiotic, victomycin, is active against a variety of Gram-positive and Gram-negative bacteria, and also has in vivo activity against solid Sarcoma 180 and Ehrlich ascites carcinoma. It belongs to the phleomycin-bleomycin group of antibiotics and has been differentiated from all known phleomycins and bleomycins by its physicochemical properties and thin-layer chromatograms.

Animals↗
PubMed1975

Platomycins A and B I Taxonomy of the producing strain and production, isolation and biological properties of platomycins.

Two new antibiotics, platomycins A and B, belonging to the phleomycin-bleomycin family, were isolated from the culture filtrate of Streptosporangium sp. MK-78. This strain has been identified as a new variety of Streptosporangium violaceochromogenes. Both platomycins A and B are active against a variety of Gram-positive and Gram-negative bacteria, and also inhibit solid Sarcoma 180 and Ehrlich ascites carcinoma.

Actinomycetales↗