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Biomedical subjects

M Koyama

Publications and source records attributed to M Koyama.

At least 271 records · Page 15Linked to original sources
PubMed1983

Pyrrolomycins F1, F2a, F2b and F3, new metabolites produced by the addition of bromide to the fermentation.

New antibiotics, pyrrolomycins F1, F2a, F2b and F3 were produced by Actinosporangium vitaminophilum sp. nov. when bromide ion was added to the fermentation medium. Addition of other halide ions such as chloride, iodide and fluoride ion showed no effect on pyrrolomycin production, affording polychlorinated pyrrolomycins A, B, C, D and E, but no F components. All four new antibiotics contain 2 approximately 4 mol of bromine, and their substitutional position was determined by X-ray analysis and synthesis, supported by spectroscopic analysis. They are strongly active against Gram-positive bacteria and fungi.

Anti-Bacterial Agents↗
PubMed1983

Structural studies on pyrrolomycins C, D and E.

Pyrrolomycins C, D and E are new members of the pyrrolomycin group of antibiotics produced by an Actinosporangium sp. The structures of pyrrolomycins C and D were determined to be 2,3-dichloro-5-(3',5'-dichloro-2'-hydroxybenzoyl)pyrrole and 2,3,4-trichloro-5-(3',5'-dichloro-2'-hydroxybenzoyl)pyrrole, respectively, by means of spectroscopic and synthetic approaches while that of pyrrolomycin E was shown to be 5-chloro-2-(3',5'-dichloro-2'-hydroxyphenyl)-3-nitropyrrole by spectroscopic data.

Anti-Bacterial Agents↗
PubMed1983

[Clinical studies of intravenous drip infusion of micronomicin. 1. Absorption and excretion].

UNLABELLED: Pharmacokinetics of MCR administered by 1 hour intravenous drip infusion were studied in healthy volunteers by two-compartment model. In 120 mg-dosage group (n = 3) studies were made by single administration, and in 60 mg-dosage group (n = 4) were administered twice daily and continued until a total of 9 doses. RESULTS: When MCR was administered in a 60 mg dosage, its Cmax was 4.3 +/- 0.3 micrograms/ml (mean +/- S.D.) after the 1st dose and 3.7 +/- 0.4 micrograms/ml after the 9th dose, while it was 8.8 +/- 1.0 micrograms/ml when the dosage was 120 mg. It should be noted that in the case of repeated dosing with 60 mg, serum levels just before administration were always below the analytical limit. The mean of T 1/2 was 1.69 +/- 0.14 hours, remaining stable at all determination. The kinetic parameters that showed different values between determinations performed after the 1st and 9th 60 mg doses were V1 (0.107 vs 0.164 L/kg) and Kel (1.02 vs 0.68 hr-1). This was also the case with comparison of 2 different dosage groups (60 mg 1st vs 120 mg; V1: 0.107 vs 0.135 L/kg, Kel: 1.02 vs 0.72 hr-1). There was no evidence indicative of side effect of MCR. DISCUSSION: The above results demonstrated that Cmax and other kinetic parameters were little influenced by whether MCR was administered by intravenous drip infusion or by intramuscular injection. There was a little larger difference in AUC between those 2 routes of administration but the differences seemed negligible when the same dosage was used. Pharmacokinetic studies are to be continued in subjects whose renal function is impaired in different ways to establish the optimum dosage regimen for MCR.

Adult↗
PubMed1982

The body surface isopotential mapping of the QRS wave in myocardial infarction. a comparative study of the scintigram with thallium-201.

When body surface isopotential mapping (MAP) is used in clinical cases of myocardial infarction, it is necessary to determine the location of the infarcted area. The present authors presumed that the positive area of MAP in normal subjects, which was altered to a negative area of MAP in myocardial infarction, was the infarcted area. In order to confirm the presumed location of the infarcted area, the location of the infarcted area on MAP and the location of infarction presumed by the scintigram with thallium-201 (SCG) were compared. MAP was divided into ten regions and a comparison between the presence or absence of an infarcted area in each segment on the MAP and of abnormal findings in each segment of the SCG was made. Consequently, the highest percentage of agreement in each region of the segment in SCG was picked up, and each region on MAP which corresponded to the segment in SCG was determined. Thereafter, each segment of MAP was matched with a wall of the ventricle: region 1--the septum; region 2--the apex; region 3--the anterior wall; region 4--the posterior portion of the apex; the upper portion of region 5--the lateral wall; region 6, 8 and 10--the inferior wall; and region 7--the posterior wall. In this way, the classification of myocardial infarction was carried out in 51 cases.

Electrocardiography↗
PubMed1982

Pharmacokinetics of cefotetan (YM09330) in humans.

The pharmacokinetics and safety of cefotetan (YM09330) were examined after intravenous administration of single and multiple doses to normal volunteers. Cefotetan was well tolerated in single doses of 500 to 3,000 mg and in multiple doses of 500 and 1,000 mg at 12-h intervals for 1 and 3 days. These doses produced high plasma levels. The half-life (3 h) of cefotetan was longer than that of cefazolin. There was no evidence of drug accumulation in the plasma in the multiple-dose study. Mean recoveries of cefotetan in urine within a 24-h period were 74.5 to 88.4% of the dose, regardless of the route of administration and the dosage. The tautomer of cefotetan accounted for approximately 5% of the dose excreted in the urine. No tautomer was detected in plasma. Concentrations of drug in plasma and urine measured by microbiological assay were in good agreement with those measured by high-pressure liquid chromatography.

Adult↗
PubMed1981

Glucose tolerance and respiratory activities of human liver biopsies: their interdependence.

To determine a possible relation of hepatic oxidative activity to glucose metabolism, the rates of oxygen consumption of liver slices from patients with chronic liver diseases were polarographically measured. The livers from patients with chronic (persistent and aggressive) hepatitis and with normal glucose tolerance showed almost the same respiratory activity as those from patients with normal livers and normal glucose tolerance, whereas the livers from patients with chronic hepatitis and with diabetic glucose tolerance (ie, diabetes mellitus secondary to chronic hepatitis) showed only a half the normal level. The decreased rate of respiration was also observed in liver slices from cirrhotics with glucose intolerance. The decrease in respiration was found in patients with normal or hyperinsulinemia as well as hypoinsulinemia responding to oral glucose load. No liver tests so far examined, except the oral glucose tolerance test, correlated with hepatic respiratory activity. It is concluded that in patients with chronic liver diseases the defect of liver respiration has a close relation to the glucose metabolism and is not necessarily associated with histological change of the liver.

Adult↗
PubMed1981

Isolation of plant tubulin from azuki bean epicotyls by ethyl N-phenylcarbamate-Sepharose affinity chromatography.

A new method for isolating plant tubulin was devised. The method involves affinity chromatography with ethyl N-phenylcarbamate and Sepharose. The protein isolated by the affinity chromatography and purified by two successive chromatographical steps on DEAE-Sephadex A-50 and Sephadex G-200 consisted of two subunits which possessed the same mobilities as the alpha- and beta-subunits of rabbit brain tubulin on SDS-polyacrylamide gel electrophoresis and showed colchicine-binding activity.

Animals↗