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Biomedical subjects

M Shibata

Publications and source records attributed to M Shibata.

At least 847 records · Page 47Linked to original sources
PubMed1976

Isolation of a new polyether antibiotic, lonomycin.

A new polyether antibiotic, lonomycin, was isolated from the culture of Streptomyces ribosidifcus strain TM-481. The antibiotic obtained as a sodium salt is a colorless prism having a molecular formula of C44H75O14Na(M.W. 850), m.p. 188 approximately 189 degrees C, and has no absorption maxima in the ultraviolet region. The infrared and NMR spectra of the antibiotic suggest the presence of a carboxyl and four methoxyl groups. Lonomycin shows antimicrobial activity against gram-positive bacteria.

Animals↗
PubMed1976

Microbial transformation of antibiotics II. Additional transformation products of maridomycin III.

Streptomyces sp. strain No. K-245 was found to transform maridomycin III into four derivatives (A1, A2, A3 and A4) in addition to the transformation products reported previously. Isolation of the main product A1 was carried out by column chromatography on silica gel developed with CHCl3-MeOH (19:1). From the partial investigation of the structure of A1, it proved to have a C-18-aldehyde group and C 4''-propionyl group but no antimicrobial activity. The relationships between A group's derivatives and known derivatives of maridomycin III are also discussed.

Anti-Bacterial Agents↗
PubMed1975

Techniques for termination of reverberating spreading depression in rats.

Reverberation of cortical spreading depression (CSD) around a circular obstacle (thermocoagulation lesion) in the frontal cortex of anesthetized rats was elicited by appropriately timed and spaced applications of KCl. The probability of continued reverberation was increased by a pyrrolopyrimidine drug BW 58-271 (10 mg/kg) from 0.93 to 0.98. Three methods of reverberation arrest were tested: a) CSD propagation was blocked by an interfering CSD wave which was initiated in the rear of the reverberating wave, passing through a narrow segment of the circular pathway, and collided with the reverberating wave on the opposite side of the obstacle; b) CSD propagation through a part of the circular pathway was blocked by a 10-min application of 10% MgCl2 on the exposed cortical surface; c) 1-min asphyxia stopped RCSD by increasing the overall refractoriness of cortical tissue. Least reliable was the interference method which stopped reverberation, even with optimum timing, only in 42% of the trials. The magnesium blockade was reliable but slow, the reverberation stopping only 30 min after MgCl2 application. Asphyxia evoked in any phase of the reverberation cycle stopped RCSD reliably and immediately. The results obtained with the interference method confirm the predictions of the mathematical model of impulse reverberation in sheets of excitable tissue. Anoxia seems best suited for practical control of CSD reverberation in functional decortication studies.

Animals↗
PubMed1975

I. Isolation and characterization of the transformation products of maridomycin III.

Three transformation products of maridomycin (MDM) III, a macrolide antibiotic, by Streptomyces lavendulae were isolated by silica gel and alumina chromatography, and designated as spots 1 (starting MDM III), 2, 3 and 4, in the order of their decreasing Rf values on thin-layer chromatogram. By mass- and NMR-spectrometry and thin-layer chromatography, spot 2 was identified as 18-dihydro-MDM III, spot 3 as 4''-depropionyl-MDM III, and spot 4 as 18-dihydro-4''-depropionyl-MDM III. The relationship between starting MDM III and these transformation products were also discussed.

Anti-Bacterial Agents↗
PubMed1975

[On the toxicity of CT-1341 evoked by long-term administration. I. Subacute toxicity of the intravenous anesthetic, CT-1341 in rats (author's transl)].

CT-1341, an intravenous anesthetic was given in various daily doses in rats for a period of one month to test the subacute toxicity. The drug was administered intraperitoneally in rats. Rats tolerated to daily administration of CT-1341 at doses of less than 1.8 ml/kg without showing other particular toxic signs than anesthesia. Main pathological findings were swelling of cells in the liver and renal tubules, and perivascular cuffing in lungs. No severe patho-histological changes were observed in any organs. Mortal cases were seen in the group of rats, in which CT-1341 was given in a daily dose of 5.4 ml/kg. A paralysis of respiratory center was suggested to be cause of death, because no severe patho-histological changes were observed in any organs of mortal rats. Survivals of this group showed no particular symptom except anesthesia, but an inhibition of the growth curve was seen in male rats only.

Alfaxalone Alfadolone Mixture↗
PubMed1975

[Phamacological studies on bamboo grass (1). Acute toxicity and anti-inflammatory and antiulcerogenic activities of water-soluble fraction(Folin) extracted from Sasa albomarginata Makino et Shibata].

Folin showed no significant toxic effects in mice. The tail pressure test in mice revealed a potent analgesic effect with a hypothermic effect in rats. A significant decrease was also seen in rat dextran or carrageenin edema. There were no inhibitory effects on the formation of granulation tissue in rats. In addition, Folin administration revealed a tendency to a decrease in pylorus-ligated ulcer of the rat by inhibiting the gastric secretion. Some protective effects from aspirin or caffeine-induced gastric ulcers of the pylorus-ligated rats were also obtained in this fraction.

Analgesics↗