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Biomedical subjects

Y Taketomi

Publications and source records attributed to Y Taketomi.

At least 19 recordsLinked to original sources
PubMed1987

Carbamylation of insulin and its biological activity.

A nonspecific binding reaction between cyanic acid formed from urea and protein or peptide is called carbamylation. In the present study, insulin, a peptide hormone, was subjected to carbamylation and the activity of carbamylated insulin was determined. Both immunological and biological activities of insulin changed on carbamylation. The decrease in biological activity in respect to glucose oxidation of fat cells or receptor-binding capacity of rat hepatocytes was greater than that in immunological activity.

Adipose Tissue↗
PubMed1985

Ultrastructure of the mandibular organ of the shrimp, Penaeus japonicus, in untreated and experimentally manipulated individuals.

The fine structure of the mandibular organ of the shrimp, Penaeus japonicus, was studied. The cells of mandibular organ contain mitochondria, smooth endoplasmic reticulum and Golgi complex. These organelles do not show any change during molt cycle. Prominent changes were observed in the cells after some steroids or proteinaceous substance. Some changes in the cells also occurred after the eyestalks were ablated. The function of the mandibular organ was considered.

Animals↗
PubMed1984

The microvilli of the midgut epithelium in the freshwater shrimp, Caridina denticulata.

The ultrastructure of the epithelial cell microvilli of the midgut of a decapod, Caridina denticulata , was studied. The microvilli have an axial bundle of filaments extend from the tip of the microvilli deeply into the interior cytoplasm of the epithelial cells. Basal globules were present at the base of the microvilli in the premolt stage animals. The length and arrangement of the microvilli change during the molting cycle.

Animals↗
PubMed1984

Absorption of experimentally administered materials by the hepatopancreas cells of the crayfish, Procambarus clarki.

After long term starvation, the crayfish, Procambarus clarki was administered protein silver, iron lactate and olive oil, and its hepatopancreas was subsequently examined by electron microscopy. The reserve cells showed changes suggesting the absorption of these materials from the acinar lumen had taken place. In contrast, the hindgut of crayfish seemed to have no absorptive ability. In crustaceans the hepatopancreas is the largest gland in the body. The chief functions of this gland are the secretion of digestive juice into the stomach and absorption of digested food. It is also where materials which are necessary for hardening of animals that have undergone ecdysis are stored. Although these roles are commonly accepted, the absorptive ability of the gland has been rarely studied. Yonge (1924) and van Weel (1955) attempted to obtain evidence for the absorptive function of hepatopancreas cells of Nephrops norvegicus and Atya spinides using iron lactate and iron saccharate, and obtained some positive results. They used the histochemical Prussian blue test to demonstrate absorbed iron. Vonk (1960) referred to the results of a few authors who had tried to show fat deposits in reserve cells of the hepatopancreas after the administration of olive oil to the animals. But because starvation did not affect the quantity of stored fat in the hepatopancreas cells, the attempt failed to reveal the absorption of fat by the hepatopancreas. In the present paper, the authors describe the results of studies on the absorption of experimentally administered materials by hepatopancreas cells of the crayfish, Procambarus clarki, using electron microscopy.

Animals↗
PubMed1978

Ultrastructural studies on the surface coat of human platelet aggregated by polylysine and dextran.

Positively charged macromolecule, polylysine (mol. wt. 15,000; 23,000; 180,000) could induce the platelet aggregation in low concentration but high concentration was required in the case of neutral macromolecule, dextran (mol. wt. 40,000; 250,000; 2,000,000). The larger molecules of polylysine and dextran were more effective in inducing platelet aggregation. In the dextran-induced aggregation, positively charged Thorotrast particles on the cell surface did not decrease significantly. On the other hand, the surface membranes of platelets aggregated by polylysine were essentially devoid of bound particles. Heparin inhibited the polylysine-induced platelet aggregation but not the dextran-induced aggregation. These findings suggested that polylysine induced aggregation more effectively than dextran by reducing the negative surface charge and giving stronger adsorption force on cell surface. In platelet-rich plasma, polylysine elicited the release reaction of 14C-serotonin but dextran did not. Possible mechanism by which polylysine could elicit the release reaction is the formation of more tightly packed platelet aggregate than that by dextran in the presence of the low calcium ion concentration in citrated platelet-rich plasma. Average distance between plasma membranes of aggregated platelets, however, did not vary with the degrees of polymerization of these macromolecules.

Adenosine↗