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Biomedical subjects

S Okuda

Publications and source records attributed to S Okuda.

At least 361 records · Page 20Linked to original sources
PubMed1979

The occurrence of uridine diphosphate N-acetylgalactosamine 6-sulfate in quail egg white and characteristic distribution of sulfated sugar nucleotides in different avian eggs.

A sulfated sugar nucleotide has been isolated from quail egg white, and accounts for nearly 80% of the total sugar nucleotides found in the egg white. Evidence is presented that this nucleotide is uridine diphosphate N-acetylgalactosamine 6-sulfate, an isomer of the 4-sulfated derivative of uridine diphosphate N-acetylgalactosamine previously found in chicken egg white. Further studies on the distribution of sulfated sugar nucleotides in egg white of various birds (chicken, quail, pheasant, peafowl, turkey, goose, and duck) demonstrate that each species has a characteristic composition, differing from one another regarding the relative amounts of 4-sulfated, 6-sulfated, and 4,6-bissulfated derivatives of uridine diphosphate N-acetylgalactosamine.

Animals↗
PubMed1979

Gross and histological types of early gastric carcinomas in relation to the acid-secreting area.

The relation of gastric acid-secreting function to the gross and histological types and locations of carcinomas was examined in 53 patients with early gastric carcinomas. Studies were made by the endoscopic Congo red test developed in this clinic. Results indicated a close correlation between the gross and histological types of early gastric carcinoma and the extent of the acid-secreting area. In general, when the acid-secreting area was large, the carcinomas were ulcerated and histologically undifferentiated and they were chiefly located in nonacid-secreting areas adjacent to acid-secreting areas, or sometimes they were surrounded by acid-secreting areas. On the contrary, when there was little or no acid-secreting area the carcinomas were polyploid and histologically differentiated, and they were located in nonacid-secreting areas far from acid-secreting areas.

Adenocarcinoma↗
PubMed1979

Relation of intestinal metaplasia to the acid-secreting area.

The distribution of intestinal metaplasia in relation to the acid-secreting are was investigated in 66 patients not suffering from gastroduodenal diseases. Studies were made via the endoscopic Congo Red test in combination with the methylene blue staining method. In this test, the acid-secreting area is identified as a "discolored" area in which Congo Red turns from red to blue-black, and areas of intestinal metaplasia were observed as areas staining blue with methylen blue. A close relationship was found between the acid-secreting area and the distribution of intestinal metaplasia; in general, intestinal metaplasia tended to be more extensive and more frequent when the acid-secreting area was small. It was also found that intestinal metaplasia increased with age. However, even in patients who were over 40 years of age, intestinal metaplasia was seen in 12.5% only, if the acid-secreting area was large. Hence, it appears likely that development of intestinal metaplasia is more closely related to the acid-secreting function than to aging.

Adult↗
PubMed1979

Thermal regulation of fatty acid synthetase from Brevibacterium ammoniagenes.

The fatty acid composition of Brevibacterium ammoniagenes was affected by the temperature of growth. As the growth temperature was lowered, the proportion of unsaturated fatty acids increased. The fatty acid synthetase obtained from B. ammoniagense produced oleic acid as well as saturated fatty acids. The ratio of unsaturated to saturated fatty acids synthesized by this enzyme in vitro was dependent on the temperature of the enzyme reaction but not on the growth temperature of B. ammoniagenes from which the enzyme was prepared. These results suggest that the changes of composition in cellular fatty acids reflect the temperature dependence of the fatty acid synthetase.

Brevibacterium↗
PubMed1979

Developmental change in striatal concentration of homovanillic acid and 3,4-dihydroxyphenylacetic acid in response to apomorphine and haloperidol treatment.

The striatal concentration of homovanillic acid (HVA) and 3,4-dihydroxyphenylacetic acid (DOPAC) was estimated following an injection of apomorphine into the developing rat subchronically treated (S.C.) with haloperidol. At the withdrawal stage of haloperidol treatment, striatal HVA and DOPAC levels decreased in the rat aged 14, 24 and 34 days. The haloperidol treatment enhanced the apomorphine-induced reduction of the striatal HVA content at the withdrawal stage in the 24-day-old and 34-day-old rat. These results suggest that a functional link in the feedback control mechanism and dopamine receptors do not fully develop at birth but do so in the early stage of postnatal life.

3,4-Dihydroxyphenylacetic Acid↗
PubMed1978

Stereochemical studies of hydrogen incorporation from nucleotides with fatty acid synthetase from Brevibacterium ammoniagenes.

The biosynthesis of fatty acids from malonyl-CoA and acetyl-CoA was investigated with an enzyme preparation which was purified 100-fold from Brevibacterium ammoniagenes. Fatty acids synthesized in the presence of D2O and stereospecifically deuterated NADPH and NADH were isolated and analyzed by mass chromatography to examine the localization of deuterium in the molecule. The following results were obtained: 1) HB hydrogen of NADPH was used for beta-ketoacyl reductase. 2) HB hydrogen of NADH was used for enoyl reductase. 3) Hydrogen atoms from water were found on the even-numbered methylene carbon atoms (2-hydrogen atoms per carbon atom) and some were also found on the odd-numbered methylene carbon. 4) Hydrogen atoms from NADPH were found on odd-numbered methylene carbon atoms (1-hydrogen per carbon). 5) Hydrogen atoms from NADH were also found on the odd-numbered methylene carbon atoms, but the number of incorporated hydrogen atoms was less than expected. The exchange of HB hydrogen of NADH with water catalyzed by enoyl reductase was suspected. 6) The exchange of methylene hydrogen atoms of malonyl-CoA with proton of water was suggested by 13C NMR analysis.

Brevibacterium↗
PubMed1978

New assay method for fatty acid synthetase with mass fragmentography.

A new assay method for fatty acid synthetase using mass fragmentography is described. The amounts of fatty acids synthesized in deuterated water are determined by mass fragmentography by monitoring the intensities of m/e 77 and m/e 74 fragment ions using heptadecanoic acid as an internal standard. This method is suitable for any fatty acid synthetase which produces several species of fatty acids and is also applicable to crude enzyme preparations. This procedure is more sensitive and specific than the conventional spectrophotometric method. Fatty acid synthetases from rat liver and Brevibacterium ammoniagenes are analyzed by this method.

Animals↗
PubMed1978

Endolymphatic stromal myosis with autoradiographic observation.

A biopsy case of endolymphatic stromal myosis, a rare neoplasm of the uterus, which occurred in a 33-year-old female was described. The histology was typical and resembled stromal cells of proliferative phase endometrium. The tumor extended in the endometrium and diffusely infiltrated into the myometrium and the parametrium. However, 3H-thymidine labeling index was low suggesting slow growth of the tumor.

Adult↗
PubMed1977

Relationship between phospholipid compositions and transport activities of amino acids in Escherichia coli membrane vesicles.

Cells of Escherichia coli were incubated in broth medium in the presence of 5 mM of hydroxylamine which completely inhibited growth but did not affect viabilities. Hydroxylamine is known to inhibit phosphatidylserine decarboxylase. A large amount of phosphatidylserine (up to 20% of total phospholipids), which did not occur in normal cells, accumulated accompanied with a decrease in phosphatidylethanolamine. Higher uptake activities of serine and glutamate were observed with the hydroxylamine-treated cells than control cells. When membrane vesicles from hydroxylamine-treated cells were prepared, they also displayed higher uptake activities of serine, proline, glutamate, and threonine than those of normal membranes. When hydroxylamine-treated cells were incubated with chloramphenicol, at concentrations which almost completely inhibited protein synthesis, the composition of phosphatidylserine decreased with a concomitant increase in that of phosphatidylethanolamine. The phospholipid composition of these cells incubated for 5 h with chloramphenicol became almost normal. Membranes vesicles prepared from such cells displayed reduced uptake activities, which were close to those of normal vesicles. These results were interpreted as indicating the altered transport activities due to the altered phospholipid composition.

Amino Acids↗
PubMed1977

Fatty acid synthetase from Brevibacterium ammoniagenes: formation of monounsaturated fatty acids by a multienzyme complex.

A multienzyme fatty acid synthetase complex isolated from Brevibacterium ammoniagenes has been purified to a specific activity of 1440 nmol of malonyl-CoA incorporated per min/mg. The enzyme is homogeneous, as judged by gel electrophoresis on agarose gels, and has a molecular weight of 1.2 X 10(6). Both NADPH and NADH are required for activity. In contrast to other fatty acid synthetase complexes, the enzyme catalyzes the synthesis of both long-chain saturated and monounsaturated fatty acids from malonyl-CoA and acetyl-CoA. The formation of unsaturated fatty acids is oxygen-independent and sharply reduced by 3-decynoyl-N-acetylcysteamine, a known inhibitor of Escherchia coli beta-hydroxydecanoyl thioester dehydrase (EC 4.2.1.60).

Aerobiosis↗
PubMed1977

Stereochemical studies of hydrogen incorporation from nucleotides with fatty acid synthetase from Brevibacterium ammoniagenes.

The biosynthesis of fatty acids from malonyl-CoA and acetyl-CoA was investigated with an enzyme preparation which was purified 100-fold from Brevibacterium ammoniagenes. Fatty acids synthesized in the presence of D2O and stereospecifically deuterated NADPH and NADH were isolated and analyzed by mass chromatography to examine the localization of deuterium in the molecule. The following results were obtained: 1) HB hydrogen of NADPH was used for beta-ketoacyl reductase. 2) HB hydrogen of NADH was used for enoyl reductase. 3) Hydrogen atoms from water were found on the even-numbered methylene carbon atoms (2-hydrogen atoms per carbon atom) and some were also found on the odd-numbered methylene carbon atoms. 4) Hydrogen atoms from NADPH was found on the odd-numbered methylene carbon atoms (1 hydrogen per carbon). 5) Hydrogen atoms from NADH was also found on the odd-numbered methylene carbon atoms, but the number of incorporated hydrogen atoms was less than expected. The exchange of HB hydrogen of NADH with water catalyzed by enoyl reductase was suspected. 6) The exchange of methylene hydrogen atoms of malonyl-CoA with protons of water was suggested by 13C NMR analysis.

Acetyl Coenzyme A↗
PubMed1977

Effect of fundusectomy on serum and antral gastrin levels in rats.

In adult male rats, fundusectomy decreased acid secretion but significantly increased total antral gastrin and both fasting and food-stimulated serum gastrin levels. The rise in fasting serum gastrin could be inhibited by antral acidification, suggesting that decreased acidity caused postfundusectomy hypergastrinemia. The mechanism for the increase in total gastrin in antral tissue is probably the same. These studies provide a useful experimental model for the increasing of antral gastrin and for the production of hypergastrinemia.

Animals↗