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Biomedical subjects

Y Oda

Publications and source records attributed to Y Oda.

At least 523 records · Page 29Linked to original sources
PubMed1989

Inhibitory effects of phenol derivatives on bovine platelet aggregation and their effects on Ca2+ mobilization.

The effects of phenol derivatives on aggregation of bovine platelets induced by ADP, thrombin, platelet activating factor, collagen and A23187 were investigated. The phenol derivatives inhibited all these induced aggregations except that by the calcium ionophore. The derivatives each inhibited the aggregations induced by ADP, thrombin, platelet activating factor and collagen, respectively, within a similar concentration range. A linear relation was found between the inhibitory potencies of the phenol derivatives and their partition coefficients between n-octanol and water (Poct values), suggesting that their interaction with hydrophobic regions of the cell was important for inhibition. Fluorescence analyses with fura-2-loaded platelets showed that in the concentration ranges in which the phenol derivatives inhibited aggregation, they also inhibited agonist-induced increases in Ca2+ both in the presence and absence of extracellular Ca2+. Moreover, a high correlation was found between the inhibitory effects of the derivatives on aggregation and their effects on Ca2+ mobilization. These results suggest that inhibition of platelet aggregation by phenol derivatives is mainly due to inhibition of the increase in cytoplasmic Ca2+ by inhibition of both intracellular Ca2+ mobilization and Ca2+ uptake.

1-Octanol↗
PubMed1989

Prostaglandin derivatives inhibit the growth of malarial parasites in mice.

New prostaglandin oligomeric derivatives, termed MR-256 and MR-356, were found to inhibit the growth of murine malarial parasites, P. chabaudi and P. vinckei, within red blood cells in vivo. When mice were infected with P. chabaudi, both MR-256 and MR-356 suppressed the growth of parasites, but MR-356 had a greater inhibitory effect than MR-256. With P. vinckei, MR-356 also inhibited the growth of parasites, and improved the survival rate. The effect of MR-256 was much less. A possible inhibitory mechanism of action of these drugs is discussed.

Alprostadil↗
PubMed1989

Expression of proto-oncogene products during drug-induced differentiation of a neuroblastoma cell line SK-N-DZ.

Four human neuroblastoma cell lines exhibited differences in their ability to differentiate into neuron-like cells in response to three different treatments, serum deprivation, or additions of dibutyryl cyclic-AMP or retinoic acid. Expression of N-myc gene product was reduced in neuroblastoma cell line SK-N-DZ differentiated by retinoic acid as compared with untreated cells. On the contrary, expression of c-src gene product, pp60c-src, was considerably enhanced in differentiated SK-N-DZ cells. Tyrosine phosphorylation of several cellular proteins was found to be enhanced in differentiated cells. Alteration in expression of these proto-oncogene products might be important in the differentiation of neuroblastoma cells into neuron-like cells.

Bucladesine↗
PubMed1989

Endogenous beta-galactoside-binding lectin expression is suppressed in retinol-induced mucous metaplasia of chick embryonic epidermis.

The fate of endogenous beta-galactoside-binding lectin of chick embryo (14K type) was investigated during the course of skin differentiation. Lectin (14K) was found in keratinized epidermis and was localized mainly in the basal and intermediate cells. However, the protein lectin in the epidermis disappeared when the cultured skin was treated with vitamin A and mucous metaplasia was observed. The synthesis of lectin mRNA was also strongly suppressed by vitamin A in a concentration-dependent manner. On the other hand, in the dermis, in which the lectin was localized in the extracellular matrix, lectin expression was scarcely affected by vitamin A. These results indicated that the lectin was expressed in the keratinized epidermis but that its expression was suppressed in vitamin A-induced mucous-secreting epithelium. The suppression may be a result of a transition of the epidermal regulatory system to one of mucous-secreting epithelium. This is the first finding that 14K lectin expression might be regulated during the course of the epidermal differentiation.

Animals↗
PubMed1989

A simple method for the Schwann cell preparation from newborn rat sciatic nerves.

We have developed a simple and relatively rapid method for obtaining a sufficient number of Schwann cells with a favorable purification ratio from newborn rat sciatic nerves. Perineurium-free nerves were torn into small fascicles of approximately 150-200 microns in diameter and explanted twice on type I collagen gel every 2 days of the culture period in order to reduce the number of contaminant fibroblasts. The last explanted tissues were fed with Dulbecco's modified Eagle medium supplemented with 10% fetal bovine serum and 100 micrograms/ml bovine pituitary extract for 10 days. More than 10 X 10(4) Schwann cells (greater than 95% purity) were obtained from newborn rat sciatic nerves.

Animals↗
PubMed1989

Characteristics of specific bindings of nitrendipine and PN200-110 to various crude membranes: induction of irreversible bindings by UV irradiation.

The characteristics of the specific bindings of [3H]nitrendipine (Nit) and [3H](+)PN200-110 (PN) to crude membranes from rat skeletal, cardiac, and uterine muscle and whole brain were investigated, with special interest in the effect of UV irradiation on these bindings. The specific bindings of [3H]Nit and [3H](+)PN to these crude membranes were saturable and reversible. The specific bindings of [3H]Nit to all these membranes except crude skeletal membranes was maximum in the presence of 0.15 M NaCl plus 1 mM CaCl2 and minimal in the absence of these ions, but the specific bindings of [3H](+)PN to these crude membranes was not affected significantly by these ions. A calcium agonist and antagonists inhibited the specific bindings of [3H]Nit and [3H](+)PN to these crude membranes, the order of their inhibitory effects on specific [3H]Nit bindings being roughly Nit greater than or equal to (+)PN greater than or equal to (-)PN much greater than Bay K 8644 (Bay) greater than verapamil (Ver) greater than diltiazem (Dil). In crude skeletal membranes only, PN caused significant stereospecific inhibition. The order of inhibitions of specific [3H](+)PN bindings to these crude membranes was generally (+)PN greater than Nit greater than or equal to (-)PN greater than Bay much greater than Ver greater than or equal to Dil. In all these crude membranes, UV irradiation completely prevented decrease in the amount of specific binding of [3H](+)PN binding on addition of excess unlabeled (+)PN. These findings suggested that [3H]Nit and [3H](+)PN bind to voltage-sensitive calcium channels in crude membranes from rat skeletal, cardiac, and uterine muscle and whole brain, and that UV irradiation changes the specific bindings of [3H]Nit and [3H](+)PN from reversible to irreversible bindings.

Animals↗
PubMed1989

Principal-Component Analysis of the Characteristics Desirable in Baker's Yeasts.

Twenty-seven properties considered to be required for good bakery products were examined in 56 industrial and 2 laboratory yeast strains. The data obtained were applied to principal-component analysis, one of the multivariate statistical analyses. The first and second principal components together were extracted, and these accounted for 77.7% of the variance. The first principal component was interpreted as the glycolytic activity of yeast in dough, and the second one was interpreted as the balance of leavening abilities in sweet and flour doughs from the factor loadings. The scattergram on the two principal components was effective in grouping the 58 yeast strains used.

Journal Article↗
PubMed1989

Genetic Analysis of Haploids from Industrial Strains of Baker's Yeast.

Strains of baker's yeast conventionally used by the baking industry in Japan were tested for the ability to sporulate and produce viable haploid spores. Three isolates which possessed the properties of baker's yeasts were obtained from single spores. Each strain was a haploid, and one of these strains, YOY34, was characterized. YOY34 fermented maltose and sucrose, but did not utilize galactose, unlike its parental strain. Genetic analysis showed that YOY34 carried two MAL genes, one functional and one cryptic; two SUC genes; and one defective gal gene. The genotype of YOY34 was identified as MATalpha MAL1 MAL3g SUC2 SUC4 gall. The MAL1 gene from this haploid was constitutively expressed, was dominant over other wild-type MAL tester genes, and gave a weak sucrose fermentation. YOY34 was suitable for both bakery products, like conventional baker's yeasts, and for genetic analysis, like laboratory strains.

Journal Article↗
PubMed1989

Inhibitory effect of lithium on the release of thyroid hormones from thyrotropin-stimulated mouse thyroids in a perifusion system.

We studied the effect of lithium on the release of T3, T4, and cAMP from perifused mouse thyroids and on cAMP content in thyroid pieces. Lithium significantly inhibited T3 and T4 release from TSH-stimulated mouse thyroids. This inhibitory effect on thyroid hormone release was dependent on the concentration of lithium. Under continuous stimulation with TSH and 3-isobutyl-1-methylxanthine, both cAMP release and cAMP content were significantly decreased by lithium. In addition, we studied the effect of lithium on (Bu)2cAMP-stimulated thyroid hormone release. T3 and T4 release was stimulated by (Bu)2cAMP in a similar way to TSH. Lithium significantly inhibited (Bu)2 cAMP-stimulated T3 and T4 release from perifused mouse thyroids. These results suggest that lithium inhibits the action of TSH in the thyroid gland by both suppression of cAMP production and inhibition at a step beyond cAMP generation.

1-Methyl-3-isobutylxanthine↗
PubMed1989

Increased production and/or secretion of pulmonary surfactant in rats by long term sulfur dioxide exposure.

Influence of long term SO2 exposure on the pulmonary surfactant in rats was studied by means of chemical analysis and microscopic verification. At a time after termination of the exposure period, the general symptom in rats was similar to that of bronchitis. The content of disaturated phosphatidylcholine, a main functional component of the pulmonary surfactant, significantly increased not only in broncho-alveolar lavage fluid but also in pulmonary microsomal fraction by long term SO2 exposure. Microscopic verification of alveolar type II cells from the bronchitic rats demonstrated the development of rough surface endoplasmic reticulums and an increase of the number of osmiophillic bodies. The results suggest that pulmonary surfactant production and/or secretion are activated in rats with bronchitis caused by long term SO2 exposure.

Animals↗
PubMed1989

Studies on chemical modification of Tulipa gesneriana lectin.

Modification of lysine, tyrosine, histidine, aspartic acid and glutamic acid residues did not affect the agglutinating activity of the Tulipa gesneriana lectin (TGL). Modification of two arginine residues per subunit in the lectin with either 2,3-butanedione or phenylglyoxal led to an almost complete loss of activity. An inactive lectin modified with 2,3-butanedione recovered a full activity on dialysis against Tris-HCl buffer. The presence of 0.1 M (alpha-1----6) linked mannotriose, a potent inhibitor of the lectin, protected all the arginine residues from modification and the lectin was fully active. Circular dichroism spectroscopy showed that no significant conformational change of TGL occurred following arginine modification. A treatment of the lectin solution with N-bromosuccinimide or 2-hydroxy-5-nitrobenzyl bromide, chemical reagents for tryptophan modification, caused turbidity of the solution, accompanied with complete loss of activity. The fluorescence emission spectrum of the lectin showed a characteristic tryptophan emission with a maximum centered at 336 nm. Upon addition of manno-oligosaccharides a decrease of the fluorescence intensity was observed, indicating that the environment of tryptophan residues altered. These results suggest that arginine and tryptophan residues are importantly involved in the sugar binding of TGL.

Amino Acids↗
PubMed1989

Electrokinetic chromatography for drug analysis. Separation and determination of cefpiramide in human plasma.

Electrokinetic chromatography using a fused silica capillary and sodium dodecyl sulfate (SDS) solution has been applied to the separation and determination of cefpiramide (CPM) in human plasma with the use of antipyrine (AP) as an internal standard. A plasma sample was introduced into the capillary by siphoning. The calibration plot for CPM in plasma sample showed good linearity in the concentration range over 10 to 300 micrograms/ml. This method has advantages over usual high performance liquid chromatography (HPLC) in that it needs only a very small volume (less than 10 nl) of plasma without pretreatment, and an extremely high separation efficiency (10 times or much higher plate number than usual HPLC) is obtained. The addition of SDS to the supporting electrolyte solution enabled (1) rapid release of protein-bound drug which allowed the total concentration to be determined, (2) reproducible results to be obtained by suppressing adsorption of protein onto the fused silica capillary and (3) rapid separation of drug from proteins by selective retardation of protein peaks.

Cephalosporins↗
PubMed1989

Protective effect of surface-active phospholipids against the acid-inducing inhibition of the tracheal mucociliary transport.

Little is known about the physiological role of surface active phospholipids (SAP) in the central respiratory tract. In the present study, the effect of SAP on acid-inducing inhibition of particle transport by the tracheal mucociliary function was investigated in unanesthetized pigeons. SAP and acids were directly nebulized to the surface of the trachea. The composition of SAP was based on that of the pulmonary surfactant. The experiment was carried out under application of acetylcholine providing a constant mucociliary transport. SAP significantly diminished HCl- and H2SO4-inducing inhibitions of the mucociliary transport. Benzalkonium chloride also reduced the inhibition. The results suggest that SAP may be a protecting factor of the mucociliary clearance and that SAP may be connected with hydrophobicity not only of the alveolar surface but of the tracheal epithelium.

1,2-Dipalmitoylphosphatidylcholine↗
PubMed1989

Effects of anticholinergic bronchodilators on mucociliary transport and airway secretion.

The effects of atropine, ipratropium and oxitropium on the mucociliary clearance were studied in pigeons and rabbits. The normal mucociliary transport (MCT) in pigeons was inhibited after the treatment by any of the three drugs at concentrations of 10(-4) to 10(-3) g/ml. These three drugs markedly inhibited eserine-induced MCT acceleration at a lower concentration than ACh-induced acceleration. The normal airway secretion was inhibited only by atropine in rabbits. The results indicate that neither oxitropium nor ipratropium depress the normal mucociliary clearance, but atropine may depress it under some conditions. Additionally, we suggest that these anticholinergic drugs might selectively affect the mucociliary transport modulated by endogenous ACh.

Acetylcholine↗
PubMed1989

Renal blood volume vs. glomerular filtration rate: evaluation with C15O and 88Ga-ethylenediaminetetraacetic acid (EDTA) study.

68Ga-EDTA (ethylenediaminetetraacetic acid) is simply and economically obtained without a cyclotron. We used renal blood volume (RBV) values obtained by C15O studies for blood activity subtraction on renal time activity curves using a positron emission tomography for the determination of the glomerular filtration rate (GFR) by intravenous 68Ga-EDTA administration. Positive correlation was revealed between the GFR and RBV values, where the ratio of blood activity in whole renal activity increased relatively as GFR value decreased. The estimation using a correction equation derived from the correlation curve was possible without a C15O study.

Blood Volume↗
PubMed1989

[A case of ischemic oculopathy followed by border zone infarction].

We reported a 72-year-old male with ischemic oculopathy due to ophthalmic artery stenosis followed by ipsilateral border zone infarction due to internal carotid artery stenosis. The patient had history of hypertension and diabetes mellitus. He had severe headache and visual disturbance of the right eye. He was diagnosed right neovascular glaucoma and left diabetic retinopathy (simple type), and received diuretics, beta-blockade and other anti-hypertensive drugs. One month later, he noticed left mild hemiparesis in a morning, and he experienced progression of left hemiparesis over a week. He was admitted to our hospital on the 11th day. He showed left complete hemiplegia, left sensory disturbance, anosognosia and left unilateral spatial neglect. His right eye was diagnosed neovascular glaucoma but left eye was normal. The 5th days CT showed low density area in the right terminal zone and bilateral periventricular lucency. At the same area, the 46th days MRI showed high intensity area in the T2-weighted image and low intensity area in the T1-weighted image. Cerebral angiography performed on the 33rd day, disclosed severe kinking at the cervical segment and 50% stenosis at the intracavernous segment in the right internal carotid artery, and 90% stenosis and post-stenotic dilatation of the right ophthalmic artery. Left internal carotid artery had each 60% stenosis at the cervical segment and the intracavernous segment. Left ophthalmic artery had severe stenosis from its beginning to distal part. This infarction was considered berder zone infarction by it's localization (terminal zone) and internal carotid artery stenosis.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1989

NMR studies on DNA hairpin structures with a five nucleotide loop.

One- and two-dimensional NMR experiments have been undertaken to investigate the structure of DNA hairpins with a five nucleotide loop. Analysis of proton NMR spectra suggests that the four hairpin structures examined have some common structural features; B-type conformation in the stem region and the same stacking pattern, 5' (XXX-turn-XX) 3', in the loop region. The phosphorus NMR spectra suggest that the conformational changes in the loop region affect the backbone conformation of the stem duplex.

Base Sequence↗