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Biomedical subjects

T Imai

Publications and source records attributed to T Imai.

At least 991 records · Page 55Linked to original sources
PubMed1979

Action of human pancreatic and salivary alpha-amylases on maltooligosaccharides: evaluation of kinetic parameters.

The kinetic studies on the reactions of human pancreatic and salivary alpha-amylases with several maltooligosaccharides (maltotetraose, maltopentaose, maltohexaose, and maltoheptaose) were carried out. The susceptibility to hydrolysis with human pancreatic alpha-amylase decreased in the order of maltopentaose, maltohexaose, maltotetraose, and maltoheptaose, while with human salivary alpha-amylase maltopentaose was hydrolysed slightly slower than maltohexaose but fairly faster than maltotetraose or maltoheptaose from a viewpoint of the rates of reactions based on the amount of substrate changed. The relative rates of production of substrates, utilized in the coupled yeast alpha-glucosidase reaction, increased in the order of maltoheptaose, maltohexaose, maltotetraose, and maltopentaose with human pancreatic alpha-amylase, while with human salivary alpha-amylase in the order of maltoheptaose, maltotetraose, maltohexaose, and maltopentaose. Thus, maltopentaose was considered to be the best substrate over maltotetraose, maltohexaose or maltoheptaose for the alpha-glucosidase coupled method of alpha-amylase determination.

Adult↗
PubMed1979

Duodenal carcinoid (apudoma) with psammoma bodies: a light and electron microscopic study.

An extremely rare case of psammomatous calcification in a nonfunctioning duodenal carcinoid tumor was studied by light and electron microscopy. The psammoma bodies were found most frequently within the lumina of the neoplastic glands. The ultrastructural features of the psammoma bodies were the marginal needle-shaped crystals and a coarse granular matrix in which a few organelles were embedded. The psammoma bodies appeared to be occasionally intracytoplasmic in position, showing no distinct limiting cytoplasmic membrane. Electron probe x-ray microanalysis revealed that the needle-shaped crystals contained calcium. The mechanism by which the psammoma bodies are formed has not been clearly explained. The above findings support the view that the psammoma bodies may occur initially in the cytoplasm of the tumor cells, followed by their release probably in a way of active excretion.

Adult↗
PubMed1979

Myelolipoma in adenoma of accessory adrenal gland.

A tumor was incidentally found at autopsy in the vicinity of the right adrenal gland of a 69-year-old man who had died of liver cirrhosis with hepatoma. Microscopic examination disclosed a myelolipoma associated with a cortical adenoma occurring in an accessory adrenal gland. No evidence of hormonal abnormalities was found in the clinical record of the patient. The association of myelolipoma with cortical adenoma occurring in an accessory adrenal gland seems very unusual, and the present case is believed to be the first reported of this type of association.

Adenoma↗
PubMed1979

Isolation and properties of a glycohydrolase specific for nicotinamide mononucleotide from Azotobacter vinelandii.

A glycohydrolase that catalyzes the irreversible conversion of NMN to nicotinamide and ribose 5-phosphate has been partially purified from a sonic extract of Azotobacter vinelandii. The enzyme is highly specific for NMN. NAD, NADP, nicotinic acid-adenine dinucleotide, nicotinamide riboside and alpha-NMN are not significantly hydrolyzed by this enzyme, nor do they compete with NMN. The enzyme also exhibits an absolute dependence on guanylic acid derivatives with following order of relative effectiveness: GTP, guanosine 5'-tetraphosphate greater than dGTP, GDP, 2'-GMP, 3'-GMP greater than GMP, dGMP. A heat-resistant, nondialyzable factor which could replace the GTP requirement was found in the sonic extract. The Ka for GTP and the Km for NMN in the presence of GTP at 1mm were calculated to be 0.025 mM and 4.5 mM respectively. GMP, dGMP, and dCMP were found to be effective inhibitors of the enzyme when 1 mM GTP was also present. The kinetic data suggest that the binding site for these mononucleotides is distinct from the active site or the GTP binding site. The ability of this enzyme to cleave NMN is suggestive of a metabolic role of the enzyme in selective conversion of NMN to nicotinamide, which, in turn, would be re-utilized by the cell as a precursor of NAD via nicotinic acid.

Azotobacter↗
PubMed1979

The omental sandwich reconstruction for a full-thickness cheek defect.

We present a case in which a large full-thickness cheek defect was successfully repaired in one stage by the "omental sandwich technique." We transferred the omentum as a free flap, anastomosing the middle omental vessels with the end stumps of the gastroepiploic vessels after they had been brought to the neck through a subcutaneous tunnel. Skin grafts were applied then on both sides of the revascularized omentum.

Carcinoma, Squamous Cell↗
PubMed1979

Comparative study of anti-endotoxic potency of dexamethasone based on its different ester types.

Difference in the anti-endotoxic potency in mice between dexamethasone 21-disodium phosphate (DM-P) and 21-sodium sulfate (DM-S) was investigated. Changes in the plasma levels of free 17-hydroxycorticoids (17-OHCS), further, were defined after intravenous administration of 2 mg/kg dexamethasone in elective surgical patients for elucidation of the metabolic basis of the different anti-endotoxic potencies of the two ester types of dexamethasone. Young male mice of DDN strain were pretreated with 0.2 mg DM-P or DM-S. Following the pretreatment, 0.5 mg of the endotoxin was administered at varying intervals of 0--24 hours, and survival rates were determined after 72 hours. In the DM-P group the mice exhibited a significant resistance to the endotoxin within two hours after the pretreatment, but in the DM-S group, the mice exhibited no anti-endotoxic potency. When different doses of dexamethasone (from 3.2 to 0.00625 mg) were administered with 0.5 mg of the endotoxin simultaneously, the mice in the DM-P group showed improvements in survival rates that tended to be dose related, but the mice in DM-S group showed no improvement in survival rates. Plasma levels of free 17-OHCS in elective surgical patients, further, were remarkably elevated after administration of DM-P, 2 mg/kg, but they showed no elevation after administration of DM-S, 2 mg/kg. Thus, it is clear that the in vivo metabolism of the two esters is different. DM-P easily liberates its free form, whereas DM-S does not. From this evidence, it was concluded that there is a close correlation between the anti-endotoxic potency of dexamethasone and its plasma level of free form, and that glucocorticoids can demonstrate their anti-endotoxic action when they are present at pharmacologically high levels in the bloodstream. There is considerable difference in biological action, moreover, between the two water-soluble esters of dexamethasone. More attention should be paid to this difference when investigating the treatment of shock with glucocorticoids.

17-Hydroxycorticosteroids↗
PubMed1978

FAD-dependent malate dehydrogenase, a phospholipid-requiring enzyme from Mycobacterium sp. strain Takeo. Purification and some properties.

FAD-dependent malate dehydrogenase, a phospholipid-requiring enzyme, was homogeneously purified from the particulate fraction of Mycobacterium sp. strain Takeo. The isolated enzyme contains no FAD and few phospholipid, and has a specific activity of 300-360 units/mg of protein. In the assay system without addition of phospholipid (cardiolipin), the enzyme activity was only about 3% of maximum activity. The molecular weight was estimated to be 51 000-55 000 by four methods. Titration by p-chloromercuribenzoate revealed the presence of one cysteine residue/mol of enzyme. The isoelectric point was found to be pH 6.9 by isoelectric focusing. From circular dichroism spectral data, the enzyme protein was found to contain alpha-helix structure of 24%.

Amino Acids↗