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Biomedical subjects

M Takeuchi

Publications and source records attributed to M Takeuchi.

At least 1,009 records · Page 56Linked to original sources
PubMed1980

Malioxamycin, a new antibiotic with spheroplast-forming activity. I. Producing organism, fermentation, isolation and characterization.

Strain No. 15748, identifies as Streptomyces lydicus, produces a new antibiotic malioxamycin. Malioxamycin is a water-soluble, amphoteric antibiotic with low molecular weight, having a valine and a malic acid moieties in its structure. It gave a positive ninhydrin and ferric chloride reactions. Malioxamycin inhibited the growth of some Gram-negative bacteria by acting on peptidoglycan synthesis in the cell wall and produced spheroplasts from those sensitive bacteria.

Anti-Bacterial Agents↗
PubMed1980

Malioxamycin, a new antibiotic with spheroplast-forming activity. II. Structural elucidation and total synthesis.

Malioxamycin (1) is a new antibiotic produced by Streptomyces lydicus No. 15748. The structure of malioxamycin has been determined by nmr and mass spectra to possess a hydroxamic acid bond between L-valine and D-malic acid. This structure was confirmed by total synthesis of the antibiotic with (R)-aminooxysuccinic acid and the active ester of L-valine.

Anti-Bacterial Agents↗
PubMed1980

Induction of duodenal tumors in F344 rats by continuous oral administration of N-ethyl-N-nitrosourea.

Forty male and 40 female inbred F344 rats were given a solution of 400 mg N-ethyl-N-nitrosourea/liter in their drinking water. Digestive tract tumors were induced in 32 males (an incidence rate of 80%) and in 28 females (an incidence rate of 70%). Among these digestive tract neoplasms, duodenal tumors occurred most frequently. Most were of the epithelial type, such as adenoma or adenocarcinoma. Tumors in hematopoletic organs were also found in 15 males (38% incidence) and in 17 females (43% incidence).

Animals↗
PubMed1980

[Mixing time of zinc phosphate cement (author's transl)].

Since the mechanical and chemical properties of zinc phosphate cements are variable under varying conditions, it is very important to obtain optimum conditions of manipulation. Many authors have written about the effect of the powder-liquid ratio, room temperature and humidity, but there are few reports on mixing technique. Consequently, we studied the influence of mixing time on the properties of the cement. Mixing time was 45 seconds, 90 seconds, 180 seconds, and 270 seconds. The results obtained were as follows. 1) The shorter the mixing time, the shorter the time to reach the maximum temperature and the higher the temperature. 2) When the mixing time was long, the setting time was prolonged. 3) Compressive strength appears the highest at the 90 seconds mixing time. In both cases, when mixing time was longer or shorter, compressive strength decreased. 4) Hardness showed the same tendency as compressive strength, and also the 90 seconds mixing time had best results. 5) As the mixing time increased, film thickness increased remarkably and was inadequate for the use of cementing.

Chemical Phenomena↗
PubMed1980

Induction of duodenal-tumors and thymomas in Fischer rats by continuous oral administration of 1-propyl-1-nitrosourea.

Male and female F344/DuCrj rats were given 400 ppm solution of 1-propyl-1-nitrosourea continuously in their drinking water. The incidence of digestive tract tumors was as high as 32/36 (89%) and 33/39 (85%) in male and female rats, respectively. Among these, duodenal tumors were induced most frequently, and most of them were adenocarcinoma followed by adenomas and hemangiogenic tumors. Thymomas were found in 27 (75%) males and 14 (36%) females. The lymphocytic type thymoma was the most frequent, and epithelial or mixed types were found only in 8 females. Other tumors induced were mainly in the ear ducts and lung, and the incidence was less than 13%.

Adenocarcinoma↗
PubMed1980

[Effects of betamethasone 17-propionate and betamethasone on hypothalamo-pituitary-adrenal cortex axis in rats (author's transl)].

Effects of betamethasone, 17, 21-dipropionate (BMDP) and betamethasone (BM) on hypothalamo-pituitary-adrenal cortex axis following the intravenous or subcutaneous administration were studied in rats. The active site of the main metabolite of BMDP -- betamethasone 17-propionate (BMP) -- and BM was investigated by the stereotaxical implantation of these glucocorticoids. The ether-induced increase of plasma corticosterone was not suppressed by intravenous administration of BMDP in a dose of 300 mu g/kg, but BM suppressed this increase at doses over 10 mu g/kg. Subcutaneous administration of a large amount of these steroids (BMDP, 20 mg/kg; BM, 16 mg/kg) induced a significant suppression of the ether-induced plasma corticosterone increase. The implantation of the main metabolite of BMDP--BMP--into the anterior or medial hypothalamic area and septum was effective in significantly reducing the ether-induced increase of plasma corticosterone. BMP implants into the posterior hypothalamus or pituitary gland proved to be ineffective. In contrast, BM, when placed into the hypothalamic area (anterior, medial or posterior), septum or pituitary, lowered the plasma corticosterone levels.

Animals↗
PubMed1979

[Ergometer test].

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Exercise Test↗
PubMed1979

Relation of pancreatic duct hyperplasia to carcinoma.

In order to find a relationship between ductal hyperplasia and carcinoma of the pancreas, histological and histochemical examinations were made on pancreatic specimens of 1,174 autopsy patients with special attention to the age incidence of the former. Ductal hyperplasia was divided into 3 types; nonpapillary, papillary, and atypical hyperplasia. All three types of hyperplasia and ductal carcinoma showed a similar tinctorial property in mucous histochemistry. In general, atypical hyperplasia was seen in the pancreas having papillary hyperplasia which was found in the pancreas associated with nonpapillary hyperplasia. All three types of hyperplasia were apparently more frequent in cancerous pancreases than in non-cancerous ones. They were also more common in the head of the pancreas than in the body and tail. Age incidence also suggests a sequential change from nonpapillary hyperplasia through papillary and atypical ones to carcinoma.

Adolescent↗
PubMed1979

Quantitative flash-methylation analysis of phenobarbital.

In phenobarbital measurement by GLC with the flash-methylation technique, using trimethylanilinium hydroxide as a methylating reagent, a small amount of water decomposed phenobarbital and interfered with the quantitative analysis. Thus, both the sample and the methylating reagent must be sufficiently dehydrated to attain quantitative analyses. The hydrolysis decomposition product of phenobarbital was N-methyl-2-phenylbutyramide, as shown by its mass spectrum. The sum of methylated phenobarbital and N-methyl-2-phenylbutyramide (if observed in the spectrum) can be used for an accurate phenobarbital assay in the present flash-methylation technique.

Chromatography, Gas↗