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Biomedical subjects

T Okada

Publications and source records attributed to T Okada.

At least 577 records · Page 32Linked to original sources
PubMed1994

[Aggressive transformation of an indolent myeloma with abdominal extramedullary plasmacytoma after 6-year period of observation].

62-year-old female, who had been under observation for an indolent myeloma for six years without therapy, was admitted because of left flank pain. Various imaging modalities disclosed left pleural effusion, and a huge abdominal tumor involving the left crus of the diaphragm, spleen, stomach, pancreatic tail, left adrenal gland, left kidney and left posterior abdominal wall. Morphological and immunological examinations revealed extensive proliferation of more anaplastic myeloma cells within the tumor and in the pleural effusion than those in bone marrow on admission or at the beginning of the period of observation. Chemotherapy reduced serum M-protein, but LDH, the volume of the pleural effusion, and the size of the tumor increased. She died of pancreatitis associated with massive bleeding from the gastric tumor. Renal function was well preserved until her terminal phase. The clinical course showed the progression of indolent myeloma into an aggressive one without chemotherapeutic intervention, implying a rare subtype in terms of the natural history of multiple myeloma.

Abdominal Neoplasms↗
PubMed1994

[Coronary artery bypass grafting for a patient with single coronary artery].

A 47-year-old man was admitted with suddenly developed chest pain. Coronary arteriography could not identify the right coronary orifice at the right coronary sinus. Left coronary arteriography revealed that the right coronary artery originated from a proximal segment of the left anterior descending artery with subtotal obstruction at the segment just distal to the bifurcation of the right and anterior descending arteries. Coronary artery bypass grafting to the middle segment of the left anterior descending artery was carried out with satisfactory result. To our knowledge, only seven cases with a diagnosis of single coronary artery who underwent coronary artery bypass grafting have been reported.

Coronary Angiography↗
PubMed1994

[A case of anaphylaxis caused by sunflower seed].

A 14 years old boy experienced an anaphylactic reaction of dyspnea, vomiting, urticaria and hypotension after he ate sunflower seeds. Specific IgE-mediated hypersensitivity to sunflower seen extract was demonstrated by skin tests and radioallergosorbent test (RAST). By immunoblotting test analysis (SDS-PAGE, Western blotting method), the allergenic activity of sunflower seem were shown to be in the MW range of 13.5 Kd.

Adolescent↗
PubMed1994

Na-K-ATPase activity in the guinea pig stria vascularis in experimentally-induced endolymphatic hydrops.

The effect of endolymphatic hydrops on the Na-K-ATPase activity in the guinea pig stria vascularis was electron microscopically and enzyme cytochemically investigated one year after experimental induction. The morphological observations revealed intercellular dropsy in the basal infoldings of the marginal cells, and shrinkage and disappearance of intermediate cells. Moreover, shrinkage of the marginal cells, especially of the basal infoldings, was occasionally observed. In spite of these morphological alterations, the Na-K-ATPase activity was still detected on the plasma membrane of the basal infoldings of most marginal cells. No remarkable differences were found among the cochlear turns of the specimens examined. However, no reaction product was detected on the basolateral plasma membrane of severely degenerated marginal cells. The present results indicate that the Na-K-ATPase of the plasma membrane of the basal infoldings of the marginal cells plays an important role in the maintenance of the unique ion concentration of the endolymph even in the endolymphatic hydropic condition, and that the Na-K-ATPase activity is attenuated in severely atrophic cells.

Animals↗
PubMed1994

[Fluconazole therapy for pediatric patients with severe candidal infections].

Three children with severe candidal infections were treated with fluconazole (FLCZ). An excellent effect or a partial effect was obtained in each case. Case 1 was a boy with candida esophagitis. He had been treated for relapsed ALL and became febrile with severe swallowing pain. FLCZ was administered intravenously and he became afebrile after 10 days of the therapy. Case 2 was a boy with candida pneumonitis. He had been treated for relapsed ALL and became febrile with diffuse infiltration in chest X-ray. FLCZ was administered intravenously and he became afebrile transiently, though fever and abnormal X-ray shadows reappeared soon and died of pneumonia and leukemic infiltrations. Case 3 was a girl with candida pneumonitis. She had been treated for relapsed neuroblastoma and became febrile and dyspneic. She was treated with intravenous FLCZ with no effects and died of pneumonia. All three patients showed positive results in 2 of 3 markers for candida infection, including, Cand-Tec, D-arabinitol and fungal index. FLCZ was well tolerated and no adverse effects or abnormal laboratory test results were observed. FLCZ was considered as an effective and safe antifungal agent in the treatment for fungal infections in children.

Adolescent↗
PubMed1994

[Vibratory perception threshold in normal volunteers].

A feasibility study on the vibratory perception threshold (VPT) in normal volunteers was conducted to detect anti-cancer drug induced peripheral neuropathy. The VPT was found to increase with age. The mean VPT in the main hand in 25 normal volunteers was significantly higher than in the other hand. No variation of VPT was observed in one day or one week. Variation of VPT in the lower extremities was detected between two examiners. In conclusion, the measurement of VPT was expected to be useful for the detection of anti-cancer drug induced peripheral neuropathy, if there is one examiner and the examined hand is specified.

Adult↗
PubMed1993

Study of interaction of carprofen and its enantiomers with human serum albumin--I. Mechanism of binding studied by dialysis and spectroscopic methods.

The binding of carprofen, a non-steroidal anti-inflammatory drug of the aryl propionic acid class [2-(6-chlorocarbazole)propionic acid], and its enantiomers to human serum albumin (HSA) has been studied by dialysis and spectroscopic methods. Binding parameters obtained by different methods were in close agreement. The binding of carprofen to HSA by both fluorescence and equilibrium dialysis (ED) methods is characterized by two sets of association constants [K1 = 5.1 x 10(6) M-1 (fluorescence) and 3.7 x 10(6) M-1 (ED), K2 = 3.7 x 10(5) M-1 (fluorescence) and 1.3 x 10(5) M-1 (ED)]. The S(+)-enantiomer of carprofen showed slightly higher affinity for HSA than its corresponding antipode by both methods. Different analyses of the binding to HSA suggested the presence of one high affinity site and five to seven low affinity sites for carprofen and its enantiomers on HSA. Fluorescence displacement data implied that carprofen primarily binds to site II, the benzodiazepine site, while the low affinity site of carprofen is site I, the warfarin site. Circular dichroism data suggested different mechanisms for the high affinity and the low affinity binding of carprofen to HSA. The data are consistent with the major part of the binding energy at site II being electrostatic and hydrophobic interactions, whereas for the low affinity binding, hydrophobic interactions. Binding was exothermic, entropy driven and spontaneous, as indicated by the thermodynamic analyses. From binding data with chemically modified HSA derivatives, it is likely that tyrosine, lysine and histidine residues are especially involved in carprofen binding to HSA, and it is most likely that the high affinity binding of carprofen is located in the N-terminal part of domain III or that section of protein plus the C-terminal part of domain II of the HSA molecule. When the binding of carprofen to HSA was compared to the binding of carprofen methyl ester to HSA (K = 0.1 x 10(6) M-1), the carboxyl group of carprofen was found to play an important role especially in the high affinity binding of carprofen to HSA. The high affinity of carprofen to HSA was independent of the conformational changes on HSA caused by N-B transition.

Anti-Inflammatory Agents, Non-Steroidal↗
PubMed1993

Study of interaction of carprofen and its enantiomers with human serum albumin--II. Stereoselective site-to-site displacement of carprofen by ibuprofen.

The site-to-site displacement of carprofen, a site II-specific drug, bound to human serum albumin (HSA) by ibuprofen, another site II-specific drug, was qualitatively and quantitatively studied by circular dichroism (CD) and equilibrium dialysis (ED). Carprofen gives rise to different CD spectra at lower (1:1) and higher (3:1) molar ratios to HSA, indicating different mechanisms for the binding of this drug to its high and low affinity sites on HSA. Ibuprofen at a 5:1 molar ratio to HSA displaces carprofen at a molar ratio of 1:1 to HSA from its high affinity binding site (site II) to its low affinity site (site I), as shown by production of the CD spectrum similar to that obtained in the case of the carprofen-HSA complex at a molar ratio 3:1. As revealed by the ED experiments, the free fraction of carprofen at a molar ratio of 1:2 to HSA (2 x 10(-5) M) was not initially increased by the addition of ibuprofen at a lower concentration, but at a higher concentration (6 x 10(-5) M), the free fraction was increased by only 90%. When site I was sufficiently blocked by a site I-specific drug like warfarin or phenylbutazone (6 x 10(-5) M), there was about a 4-fold increase in the free fraction of carprofen caused by ibuprofen. This site-to-site displacement demonstrated by carprofen was found to be stereospecific as indicated by the highest interaction between the S(+)-enantiomers of carprofen and ibuprofen. Moreover, the displacement of carprofen occurred at the azapropazone region rather than the warfarin region of site I on HSA.

Anti-Inflammatory Agents, Non-Steroidal↗
PubMed1993

Nanosecond laser photolysis of iodopsin, a chicken red-sensitive cone visual pigment.

The photobleaching process of iodopsin (a chicken red-sensitive cone visual pigment) purified in a detergent system containing CHAPS and phosphatidylcholine was investigated by means of nanosecond laser photolysis at room temperature. Excitation of iodopsin with a nanosecond laser pulse (wavelength, 560 nm; pulse width, 17 ns) resulted in the formation of at least four intermediates on the nanosecond to millisecond time scale. The earliest intermediate detected had an absorption maximum at 571 nm, which was very close to that of original iodopsin (lambda max = 567 nm), and remarkably blue-shifted as compared with that of bathoiodopsin [lambda max = 625 nm; Kandori et al. (1990) Proc. Natl. Acad. Sci. U.S.A. 87, 8908-8912]. The intermediate, named BL-iodopsin, converted to the next intermediate, lumiiodopsin (lambda max = 535 nm), with a time constant of 130 ns. The BL intermediate had an absorption maximum just between batho- and lumiiodopsins, and an extinction coefficient comparable with these intermediates. These properties are different from those of the corresponding intermediate of rhodopsin [BL(BSI)-rhodopsin], suggesting that the binding of chloride to iodopsin, but not to rhodopsin, has an influence upon changes of the chromophore-opsin interaction in the early stage of photobleaching of iodopsin. Lumiiodopsin converted to metaiodopsin I (lambda max < 500 nm) with a time constant of 230 microseconds, and then to metaiodopsin II (lambda max = 390 nm) with a time constant of 6 ms. A thermal equilibrium between metaiodopsin I and II was established, but unlike meta intermediates of rhodopsin, they showed little temperature dependence.

Animals↗
PubMed1993

Insulin-stimulated GLUT4 translocation is relevant to the phosphorylation of IRS-1 and the activity of PI3-kinase.

We examined the role of 185-kDa insulin receptor substrate-1 (IRS-1) and phosphatidylinositol 3-kinase (PI3-kinase) in the signaling pathway of insulin-stimulated GLUT4 translocation. We had already developed a novel cell line to detect GLUT4 on the cell surface, directly and sensitively (Kanai, F., Nishioka, Y., Hayashi, H., Kamohara, S., Todaka, M., and Ebina, Y. (1993) J. Biol. Chem. 268, 14523-14526). We stably expressed a mutant insulin receptor in which Tyr972 was replaced with phenylalanine. Insulin-stimulated tyrosyl phosphorylation of IRS-1 and GLUT4 translocation were decreased in cells expressing the mutant receptor, as compared to findings in cells expressing the normal receptor. Wortmannin, an inhibitor of PI3-kinase, inhibits the insulin-stimulated PI3-kinase activity and GLUT4 translocation at 50 nM, but not the NaF-stimulated GLUT4 translocation. These results suggest that the tyrosine phosphorylation of IRS-1 and activation of PI3-kinase may be involved in the signaling pathway of the insulin-stimulated GLUT4 translocation.

Androstadienes↗
PubMed1993

Contraction of smooth muscle by activation of endothelin receptors on autonomic neurons.

Endothelin receptors, predominantly of the ETB type, were localized to cell bodies, processes, and varicosities of cholinergic and adrenergic intramural autonomic neurons that were present in primary cultures of guinea pig tracheal smooth muscle. Stimulation of the neuronal ETB receptor produced a tetrodotoxin-sensitive increase in the intracellular calcium concentration in neurons which was followed by contraction of the neighboring smooth muscle cells. These observations suggest that endothelins can induce smooth muscle contraction by means of a neuronally mediated mechanism, in addition to their direct actions on the smooth muscle.

Animals↗