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Biomedical subjects

S Moriuchi

Publications and source records attributed to S Moriuchi.

At least 91 records · Page 5Linked to original sources
PubMed1975

Demonstration of two different vitamin D-dependent calcium-binding proteins in rat intestinal mucosa.

The characteristics and location of rat intestinal proteins with calcium binding properties were reexamined using both a 45Ca-equilibrated Sephadex G-100 column and the chelex 100 method in the assay of 45Ca binding activity. The rat intestinal mucosa was found to have three different proteins with calcium binding properties. Two of these proteins were found to be vitamin D-dependent and were examined in detail. The larger vitamin D-dependent protein, found predominantly in the jejunum and ileum, had a molecular weight of 27,000 and demonstrated low affinity for calcium; the detection of this protein by the chelex 100 assay was very difficult. The smaller vitamin D-dependent protein, which was associated mainly with duodenum and jejunum, had a molecular weight of 12,500, and demonstrated a high affinity for calcium.

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PubMed1975

The effects of maltitol on rat intestinal disaccharidases.

1. The highese disaccharidase activity for sucrose maltose and maltitol was found in the jejunum, followed by the ileum and duodenum. However, the disaccharidase activity for maltitol was extremely low compared with that for sucrose and maltose. 2. For maltitol, the Km value was very large and the Vmax value was very low compared compared with the values for sucrose and maltose. 3. The initial velocity (v) in the presence of the sucrose and maltitol, was equal to the sum of the rates for individual substrates sucrose ann maltitol (v1, v2) respectively (v=v1+v2). Thus, no competition between these substrates was observed. In the case of maltose and maltitol, the initial velocity (v) in the presence of both substrates was less than the sum of the individual rates for maltose and maltitol (v1, v2) in the absence of the other substrate (v is less than v1 + v2). This finding demonstrates that there is competition between these two substrates for the same enzyme. Furthermore, the apparent Michaelis constant (Km) and the apparent maximal velocity (Vmax) for pure and mixed substrates, i.e., maltose and maltitol, at various mole fractions of maltose showed dependence on the mole fraction of maltose. The obtained kinetic data provide strong evidence that both maltose and maltitol react at the single active center of maltase.

Animals↗
PubMed1975

Binding of 7-dehydrocholesterol to sterol carrier protein and vitamin D3 effect.

It was confirmed that delta 5,7-sterol delta 7-reductase activity was suppressed by cholecalciferol (vitamin D3) in the enzyme system consisted of microsomes and sterol carrier protein (SCP). The enzyme activity was significantly decreased in the combination with microsomes obtained from either vitamin D-deficient or vitamin D3-treated rat liver and with SCP obtained from vitamin D3-treated rat. It was also demonstrated by the binding assay of the dextran-charcoal technique that 7-dehydrocholesterol binding to SCP could be specifically displaced by vitamin D3. The inhibition of cholecalciferol on 7-dehydrocholesterol binding to liver SCP was confirmed to be non-competitive inhibition.

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PubMedDate not supplied

Cytotoxic effects of a new antitumor antibiotic, FK973, in malignant glioma.

A novel antitumor antibiotic, 11-acetyl-8-carbamoyloxymethyl-4-formyl-14-oxa-1, 11-diazatetracyclo [7.4.1.0(2,7).0(10,12] tetradeca-2,4,6-trien-6,9-diyl diacetate, FK973, was obtained as a fermentation product from Streptomyces sandaensis. This drug showed excellent cytotoxic effects on human glioblastoma and medulloblastoma and murine glioma (203 glioma) cells. The antitumor effects were also observed in ACNU-resistant glioma cells. The median survival time (MST) of MG models was 15 days. When they were treated with FK973, their MST was prolonged to 21 days. FK973 showed no apparent damage to murine brain cells.

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PubMedDate not supplied

In vitro assessment for neurotoxicity of antitumor agents before local administration into central nervous system.

In vitro assays for neurotoxicity with the aid of cultured mouse fetal neurons and glial cells were applied to investigate neurotoxicity of recombinant murine interferon-beta (rMuIFN-beta). These data were compared with those for MTX, ADR, and ACNU. The range of concentrations of the drugs used in these experiments spanned their clinically achievable concentrations in patient serum (IFN-beta: 1 x 10(4) IU/ml, MTX: 100 micrograms/ml, ADR: 20 micrograms/ml, ACNU: 20 micrograms/ml). rMuIFN- beta damaged both neurons and glial cells at concentrations of more than 1 x 10(5) IU/ml but did not damage them at 1 x 10(4) IU/ml or less. Microtubule-associated protein 1A (MAP1A) staining was decreased in rMuIFN-beta-treated (more than 1 x 10(5) IU/ml) neutrons. In conclusion, since IFN-beta may have some neurotoxic effects at concentrations higher than 1 x 10(5) IU/ml, it should be administered carefully, as should other antitumor agents, into the tumor cavity in the CNS following surgery.

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PubMedDate not supplied

A novel PNET cell line with melanotic differentiation.

The primitive neuroectodermal tumor (PNET) cell line, ONS-99, was established from a human melanotic neuroectodermal tumor of infancy (MNTI). ONS-99 cells were polygonal adherent cells and transplantable to BALB/c-nu/nu mouse. ONS-99 cells were positive for NSE, HMB-45 (melanoma-associated antigen) and N-myc, but lacked the antigenic features of terminally differentiated neurons or glias. ONS-99 cells had many intermediate filaments in the cytoplasm and tight intercellular junctions with scant cytoplasmic structures by electron microscopy. To date, ONS-99 is the only example of an established PNET cell line with melanotic differentiation.

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