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Biomedical subjects

S Okuda

Publications and source records attributed to S Okuda.

At least 325 records · Page 18Linked to original sources
PubMed1982

Healing and recurrence of duodenal ulcers in relation to the acid-secreting area.

The relation of the gastric acid-secreting area to the healing and recurrence of duodenal ulcers was examined in 67 patients with duodenal ulcers. Studies were made by the endoscopic Congo red test developed at this institute. Results indicate a close correlation between the healing and recurrence of duodenal ulcers, and the extent of the acid-secreting area. In general, when the acid-secreting area was large, the ulcers did not heal satisfactorily within 4 weeks after initiation of medical treatment and frequently recurred. In contrast, when the acid-secreting area was small, the ulcers tended to heal rapidly and not to recur.

Congo Red↗
PubMed1982

Propionyl-Coa induced synthesis of even-chain-length fatty acids by fatty acid synthetase from Brevibacterium ammoniagenes.

The product distribution of Brevibacterium ammoniagenes fatty acid synthetase has been investigated using propionyl-CoA instead of acetyl-CoA as the primer. The synthetase produces not only an odd-numbered fatty acid (heptadecanoic acid) but also even-numbered fatty acids (stearic and oleic acids) in the presence of propionyl-CoA. The amounts of heptadecanoic, stearic and oleic acids increased with increasing concentration of propionyl-CoA. However, the formation of heptadecenoic acid (C17:1) was not observed under any conditions tested. The failure of C17:1 synthesis suggested that the enzyme component catalyzing the beta, gamma-dehydration, which is responsible for the synthesis of unsaturated fatty acids, has a high degree of chain length specificity. Under standard assay conditions, stearic acid predominated and heptadecanoic and oleic acids were found in lesser amounts. Mass spectrometric analyses of fatty acids synthesized either from [2H]propionyl-CoA or in 2H2O revealed that propionyl-CoA is utilized as the priming substrate for the synthesis of heptadecanoic acid and that an acetyl residues, which is formed by the decarboxylation of malonyl-CoA, served as the priming substrate for the syntheses of stearic and oleic acids. No evidence was obtained for the direct decarboxylation of malonyl-CoA to acetyl-CoA in this reaction. It is concluded that the decarboxylation of the malonyl moiety bound to the synthetase occurs efficiently only in the course of fatty acid synthesis. A hypothetical scheme is presented to explain the propionyl-CoA-dependent decarboxylation of the malonyl moiety.

Acetyl Coenzyme A↗
PubMed1982

Mechanism of action of cerulenin on fatty acid synthetase. Effect of cerulenin on iodoacetamide-induced malonyl-CoA decarboxylase activity.

Cerulenin, an antibiotic with the structure of (2R)(3S)-2,3-epoxy-4-oxo-7,10-dodecadienoylamide, irreversibly inactivates yeast fatty acid synthetase. Of all catalytic activities of the synthetase, only the condensation reaction is inhibited by cerulenin. At 0 degrees C and pH 6.5, the second-order rate constant of k = 88 M-1 . S-1 was obtained for the inactivation by cerulenin. This value was about 90-times greater than the rate constant for the inactivation of the enzyme by iodoacetamide. The enzyme was protected against the action of cerulenin by prior treatment with acetyl-CoA but not malonyl-CoA. Treatment of the enzyme with iodoacetamide, while impairing the synthetase activity, induced malonyl-CoA decarboxylase activity [Kresze, G.-B., Steber, L., Oesterhelt, D., and Lynen, F. (1977) Eur. J. Biochem. 79, 191-199]. Cerulenin had no effect on the malonyl-CoA decarboxylase activity of the iodoacetamide-treated enzyme. N-Ethylmaleimide, in contrast, inhibited the iodoacetamide-induced malonyl-CoA decarboxylase activity. When the enzyme was preincubated with cerulenin, malonyl-CoA decarboxylase activity could not be detected even after treatment of the enzyme with iodoacetamide. These results indicated that the reaction of cerulenin with the peripheral SH-groups of the synthetase is responsible for the inactivation.

Antifungal Agents↗
PubMed1982

Studies on the metabolism of unsaturated fatty acids. IX. Stereochemical studies of the reaction catalyzed by trans-2-enoyl-coenzyme A reductase of Escherichia coli.

The steric course of the reaction catalyzed by NADPH-dependent trans-2-enoyl-CoA reductase from Escherichia coli was investigated. trans-2-[6,7,8-2H7]Octenoyl-CoA was synthesized as a substrate and incubated with partially purified trans-2-enoyl-CoA reductase in the presence of 4R- or 4S-[4-2H1]NADPH. The deuterium-labeled octenoyl-CoA was also incubated with the reductase in the presence of NADPH in 2H2O. Aliquots of octanoic acids formed were analyzed, after esterification, by gas chromatography-mass spectrometry (GC-MS) to demonstrate that the pro-4R hydrogen of NADPH was incorporated into the C-3 position of octenoyl-CoA and that hydrogen from water was introduced into the C-2 position of octenoyl-CoA. The remaining portions of octanoic acids isolated from the incubation mixtures were converted to their CoA esters by the action of acyl-CoA synthetase, and they were dehydrogenated by treatment with acyl-CoA oxidase, which had previously been shown to catalyze the anti-elimination of the pro-2R and pro-3R hydrogen atoms of acyl-CoA. The deuterium contents of the products were also analyzed by GC-MS, and the results indicated that the reduction catalyzed by NADPH-dependent trans-2-enoyl-CoA reductase occurred by an anti-addition of hydrogen via a 2-Re, 3-Re attack on the trans-double bond of the substrate.

Deuterium↗
PubMed1982

The eosinophilic and amyloid-like materials in adenomatoid odontogenic tumor.

This paper is concerned with the relationship between eosinophilic material (EM) and amyloid-like material and adenomatoid odontogenic tumors. In duct-like structures between opposing rows of tall columnar cells, EM did not stain for amyloid. Under electron microscopy, EM was composed of fibrillar and granular materials, and the fibrillar material was not amyloid. Two different kinds of EM were found in solid cell masses. Lesions from cases 2, 3, 4 and part of case 1 contained small droplet-shaped EM and these EM did not stain for amyloid. Case 1 also contained EM that stained positively for amyloid. The structure of amyloid positive EM resembled developing enamel of human tooth germs. This material was tubular and finely granular. The tubular material resembled enamel matrix fibers rather then amyloid and the fine granular material was stippled. The cells surrounding EM appeared similar to ameloblasts between secretory and maturation stages.

Adolescent↗
PubMed1982

Studies on macrocyclic lactone antibiotics. VI. Skeletal structure of copiamycin.

Skeletal structure of copiamycin (1) (C54H95N3O17), a potent antifungal antibiotic, was determined from the physicochemical properties of this compound and of its degradation products. This compound consists of 32-membered polyhydroxy lactone ring, an alpha, beta-unsaturated ester group, as well as a side chain with a disubstituted guanidine moiety as its terminal. One of the hydroxyl groups (presumably at C-19) forms a hemiketal ring with the keto group at C-15, and another (at either C-21 or C-23) forms a hemiester with a malonic acid moiety.

Anti-Bacterial Agents↗
PubMed1982

Cadeguomycin, a novel nucleoside analog antibiotic. II. Improved purification, physicochemical properties and structure assessment.

Cadeguomycin, a new nucleoside analog antibiotic, has been purified as colorless needle crystals by recycling preparative HPLC. The antibiotic, C12H14O7N4, mp 231 approximately 239 degrees C (dec.), FD-MS: m/z 326 (M+); is a weakly acidic substance, showing UV gamma H2Omax (epsilon) 232 (19677), 272 (6881) and 298 nm (7607), and IR nu KBrmax 1650 (C = O) and 3420 (NH or OH) cm-1. The UV spectrum is similar to other pyrrolo[2,3-d]pyrimidines. The structure of cadeguomycin, 2-amino-3,4-dihydro-4-oxo-7-beta-D-ribofuranosyl-7H-pyrrolo[2,3-d]pyrimidine-5- carboxylic acid, has been elucidated by 1H NMR and 13C NMR in comparison with other pyrrolo[2,3-d]pyrimidines and their nucleosides.

Anti-Bacterial Agents↗
PubMed1982

Accessory cell function in tumor-bearing mice and effects of Corynebacterium parvum.

Primary in vivo production of antibody to sheep red blood cells (SRBC) was consistently suppressed in EL 4 tumor-bearing C57BL/6 mice, but the secondary response was not suppressed. This suppressed primary in vivo production of antibody was partially restored by systemic administration of Corynebacterium parvum. For investigation of the mechanism of the immunosuppression in tumor-bearing mice and the effects of C. parvum, the accessory cell function of adherent cells from tumor-bearing mice and C. parvum-treated tumor-bearing mice in in vitro cultures was studied. Peritoneal and splenic cells from tumor-bearing mice were less efficient in promoting in vitro production of antibody to SRBC by macrophage-depleted normal nonadherent cells than the adherent cells from normal mice. C. parvum treatment restored the accessory cell function of splenic adherent cells from tumor-bearing mice but not that of peritoneal cells. Furthermore, adherent cells from tumor-bearing mice did not show suppressive activity against the in vitro plaque-forming cell response.

Animals↗
PubMed1981

Steric course of reaction catalyzed by the enoyl acyl-carrier-protein reductase of Escherichia coli.

The steric course of the reaction catalyzed by Escherichia coli enoyl acyl-carrier-protein reductase was studied. 1. trans-2-[2-2H1]Decenoic and trans-2-[3-2H1]decenoic acids were synthesized and converted to the corresponding decenoyl thiol esters with CoA or acyl carrier protein. These deuterium-labeled decenoyl thiol esters were incubated with purified enoyl acyl-carrier-protein reductase in the presence of NADPH or NADH. 2. The unlabeled trans-2-decenoyl thiol esters were incubated with enoyl acyl-carrier-protein reductase in the presence of (4S)-[4-2H1]NADH. The unlabeled decenoyl thiol esters were also incubated with the enzyme in 2H2O. The decanoic acids formed in the above incubations were extracted and subjected to the action of acyl-CoA oxidase, which had been previously shown to catalyze the anti elimination of the pro-2R and pro-3R hydrogens of acyl-CoA. The resulting products, 2-decenoyl-CoAs, were converted to methyl esters and their deuterium contents were analyzed by gas chromatography/mass spectrometry. The results suggested that the reduction catalyzed by E. coli enoyl acyl-carrier-protein reductase occurs by a syn addition of hydrogen via a 2-Re, 3-Si attack on the double bond.

Acyl Carrier Protein↗
PubMed1981

Hepatic clear cell carcinoma associated with hypoglycemia and hypercholesterolemia.

Two autopsy cases of clear cell variant of hepatocellular carcinoma were reported in which both hypoglycemia and hypercholesterolemia occurred simultaneously. The tumor consisted of lipid-laden clear cells with centrally located nuclei. Glycogen was also stored in the cytoplasm in Case 2 but not in Case 1. In reference to the literature, it was suggested that hypoglycemia and hypercholesterolemia are due to biochemically heterogeneous mechanisms that vary from patient to patient and may involve diversion, hitherto undescribed, of glucose metabolism of tumor tissue in the direction of lipogenesis and/or glycogenesis.

Adenocarcinoma↗
PubMed1981

Polyps in the acid-secreting area of the stomach.

The relation of gastric polyps to acid-secreting mucosa was examined in 120 patients with gastric polyps. Studies were made by the endoscopic Congo red test developed in this clinic. In 23 patients (19.1%) gastric polyps were located in acid-secreting mucosa and may have arisen from normal oxyntic mucosa. These polyps were of two histological types: oxyntic gland polyps containing many parietal cells, and nonoxyntic gland polyps without parietal cells. Only the former type appeared to secrete acid, judging endoscopically from the change of Congo red from red to blue-black on the surface of the polyps after administration of gastrin.

Adult↗
PubMed1981

A new gastrocamera technique using infrared color film.

An attempt at infrared photography of the human gastric mucosa was made using the Olympus fiberoptic gastrocamera type S2 (GTF-S2) and Kodak Ektachrome Infrared Film (IE Film) (4). By critical selection of the illumination balance with No. 12 and doubled CC50C-2 of Kodak Wratten Filters (3), vessel patterns of the mucosa and deeper layers were photographed in orange and dark blue respectively; these patterns were invisible to the naked eye and were also not recorded by an ordinary gastrocamera.

Color↗
PubMed1981

A new method for the preparation of acyl-CoA thioesters.

A method is described for the preparation of CoA thioesters of fatty acids. Acyl-CoA thioester was synthesized by way of 1-acylimidazole and purified by high performance liquid chromatography. This method is applicable to the preparation of a variety of acyl-CoA thioesters of various chain lengths (from C2 to C18) and with varying degrees of unsaturation. It is particularly suitable for preparing acyl-CoA thioesters of labeled fatty acids or fatty acids available only in small amounts.

Acyl Coenzyme A↗