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Biomedical subjects

N Okuyama

Publications and source records attributed to N Okuyama.

At least 19 recordsLinked to original sources
PubMed1995

Enhancement of 5-hydroxytryptamine-stimulated phosphoinositide hydrolysis in the rat cerebral cortex by repeated immobilization stress.

The present study was undertaken to investigate the influence of repeated immobilization stress on phosphoinositide hydrolysis induced by 5-hydroxytryptamine (5-HT) and noradrenaline in the rat cerebral cortex. Three groups of rats subjected to stress intervention were immobilized for 2 h per day for 3, 7, and 14 days. The stress intervention of any duration did not alter noradrenaline-stimulated phosphoinositide hydrolysis. The 3- and 7-day repeated immobilization enhanced 5-HT-stimulated phosphoinositide hydrolysis, whereas the characteristics of 5-HT2 receptor binding did not change. Chronic treatment with imipramine partially, but significantly, suppressed the increase in 5-HT-stimulated phosphoinositide hydrolysis, induced by the 3-day repeated immobilization. These findings imply that modulation of 5-HT-stimulated phosphoinositide hydrolysis occurs in stressful situations and that the therapeutic effects of tricyclic antidepressant drugs might be related to the modulation of phosphoinositide hydrolysis mediated by 5-HT receptors.

Animals↗
PubMed1995

[A case of Addison's disease complicated by lung carcinoma treated with surgical resection--a case report].

Surgery was successful in a 72-year-old man with Addison's disease complicated by right lower lobe carcinoma of the lung. The patient had been diagnosed Addison's disease 25 years earlier and had been treated with cortisone acetate 25 mg every morning. A tumor shadow was found in the right lower lobe of the lung on chest X-ray. Squamous cell carcinoma was diagnosed by cytological examination. Right lower lobectomy with partial resection of the right diaphragma and lymph-node dissection were performed. The bronchial stump was closed using Sweet's method and covered with a pericardial fat pad. The intra- and post-operative course was uneventful with intravenous administration of adequate doses of hydrocortisone. The patient has been free from the carcinoma for two years.

Addison Disease↗
PubMed1994

Evaluation of thymidylate synthase RNA expression by polymerase chain reaction.

5-Fluorouracil (5FU), an antimetabolite often used for the treatment of breast cancer, binds to and inactivates the enzyme thymidylate synthase (TS). Measurement of TS levels may be useful in examining resistance to 5FU, but current methods involving ligand binding assays present considerable problems due to the low basal level of this enzyme in many tissues. Therefore, a semiquantitative polymerase chain reaction (PCR) technique to measure TS RNA concentration in breast tumour cell lines has been developed with potential for measuring TS RNA levels in individual breast tumours. Using less than 1 microgram of total RNA, we determined that the T47D breast cancer cell line expressed TS levels 1.3 to 4.4 times lower than those of four other breast cancer cell lines, MCF-7, MDA-MB-468, MDA-MB-231, and MDA-A1R. Using the MCF-7 cell line as a representative of relatively high TS expression, the relationship between the S-phase fraction (SPF), and TS levels in MCF-7 and T47D cells was next examined because cell cycle kinetics can also influence drug response. TS expression was directly related to SPF. MCF-7 cells had a higher SPF, corresponding to their higher TS level relative to T47D cells. Lastly, 5FU sensitivity was assayed for and it was found that MCF-7 cells were more sensitive to 5FU than T47D, despite having higher TS levels. A semiquantitative technique for assessing TS RNA expression by PCR in breast cancer cell lines has been demonstrated. In the cell lines tested, there was no direct relationship between TS level and 5FU sensitivity, though there was a direct relationship between cell proliferation and sensitivity to 5FU.

Base Sequence↗
PubMed1992

Influence of the acute stress on agonist-stimulated phosphoinositide hydrolysis in the rat cerebral cortex.

1. The present study was carried out in order to elucidate the influence of the acute stress on alpha 1-adrenergic, serotonin-2 (5-HT2) and muscarinic cholinergic (M-Ach) receptors-mediated phosphoinositide (PI) hydrolysis in rat cerebral cortex slices. 2. In rat cerebral cortex slices, noradrenaline (NA), serotonin (5-HT) and carbachol stimulated [3H]inositol-monophosphate (IP1) accumulation in a concentration-dependent manner. 3. The forced swimming test (FST) for 15 min induced a significant reduction of 5-HT-stimulated [3H]IP1 accumulation, but this stress situation did not produce a significant alteration of NA- and carbachol-stimulated [3H]IP1 accumulation. 4. The FST for 15 min did not affect the density and affinity of alpha 1-adrenergic, 5-HT2 and M-Ach receptors. 5. In a mild acute stress situation, the intracellular signal transduction mediated by 5-HT was promptly inhibited as compared to the signal transduction mediated by NA or carbachol. This inhibition may be induced by an acute uncoupling of 5-HT2 receptor-mediated intracellular signal transduction.

Adrenergic alpha-Agonists↗
PubMed1992

Differences in cellular proteins between high and low metastatic potential sublines from the methylcholanthrene-induced rat fibrosarcoma cell line.

The purpose of the present study was to determine with two-dimensional electrophoresis whether two sublines (high and low metastatic potential to lymph nodes) of rat fibrosarcoma induced by methylcholanthrene have differences in cellular proteins. The high metastatic potential subline had a specific protein in the protein map of the whole cell lysate. Its isoelectric point was 6.4 and the molecular weight was 18,000. This specific protein appeared in maps of the precipitate of 1,000 g centrifugation and in the supernatant from treatment with 0.5% Nonidet P-40 (NP-40). But this specific protein was not stained by five lectins, concanavalin A, wheat germ agglutinin, Ulex europeus agglutinin-1, Dolichis biflorus agglutinin, and Ricinus communis agglutinin. Apparently, this high metastatic potential subline has a specific protein in the plasma membrane which has no glycochain.

Animals↗
PubMed1981

Mutagenicity studies on alcohol extracts from gamma-irradiated potatoes--preparation of samples and their chemical analysis.

The preparation of alcohol extracts from gamma-irradiated potatoes of the "Danshaku" variety and their chemical aspects were studied. The final concentrate of alcohol extracts from potatoes showed pH values of 3-4. The o-quinones or "radiotoxins" reported by Kuzin, et al. were not detected in the alcohol extracts from potatoes of this variety by high performance liquid chromatography (HPLC) analysis, paper chromatography and the model enzymatic experiment.

Alcohols↗
PubMed1980

Purification and characterization of calcium-binding protein containing gamma-carboxyglutamic acid from rat bone.

A gamma-carboxyglutamic acid (Gla)-containing protein was purified from rat femur cortical bone. The presence of 4 Gla residues in the rat protein was shown by amino acid analysis on alkaline and acid hydrolysates. The protein was extracted from rat cortical bone with 0.5 M EDTA (pH 7.6) and purified from the EDTA extracts by gel filtration on Sephadex G-100 and ion-exchange chromatography on DEAE-Sephadex A-25. The protein has a molecular weight of about 6,000 on the basis of amino acid composition. The protein had 56 amino acid residues containing significant amounts of Asp, Glu, and Gla (acidic amino acids). The protein showed calcium-binding activity with Kd = 0.2 mM and calcium-dependent electrophoretic mobility.

1-Carboxyglutamic Acid↗
PubMed1973

[Insulin].

Explore the source record for details and available documents.

Amino Acid Sequence↗