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Biomedical subjects

H Ono

Publications and source records attributed to H Ono.

At least 487 records · Page 27Linked to original sources
PubMed1988

Effects of two treatments on semen from different bulls on in vitro fertilization results of bovine oocytes.

The semen of six different bulls was used to examine the effects of treatment with caffeine or caffeine plus Ca-ionophre on in vitro fertilization, cleavage and development into morulae of in vitro matured bovine oocytes. In vitro fertilization results (formation of both pronuclei, cleavage and development to >or= four-cell stage were significantly (P<0.01) higher using caffeine plus Ca-ionophre than those using only caffeine. The rates of fertilization and first cleavage were only slightly variable among the bulls. However, the present data showed significant variability in formation of both pronuclei (36 to 75%) of fertilized ova and development to the >or=4 cell stage (39 to 71%) by different bulls. Development into morulae of ova recovered from the rabbit oviduct did not show any significant differences in relation to sperm treatments or individual bulls.

Journal Article↗
PubMed1988

Dynamic occlusion and motion parallax in depth perception.

Random-dot techniques were used to examine the interactions between the depth cues of dynamic occlusion and motion parallax in the perception of three-dimensional (3-D) structures, in two different situations: (a) when an observer moved laterally with respect to a rigid 3-D structure, and (b) when surfaces at different distances moved with respect to a stationary observer. In condition (a), the extent of accretion/deletion (dynamic occlusion) and the amount of relative motion (motion parallax) were both linked to the motion of the observer. When the two cues specified opposite, and therefore contradictory, depth orders, the perceived order in depth of the simulated surfaces was dependent on the magnitude of the depth separation. For small depth separations, motion parallax determined the perceived order, whereas for large separations it was determined by dynamic occlusion. In condition (b), where the motion parallax cues for depth order were inherently ambiguous, depth order was determined principally by the unambiguous occlusion information.

Attention↗
PubMed1988

Solubilization and Characterization of a Membrane-Bound Auxin-Binding Protein from Cell Suspension Cultures of Nicotiana tabacum.

A membrane-bound auxin-binding protein (MABP) was solubilized by Triton X-100 from cell suspension cultures of Nicotiana tabacum L. Solubilization of MABP was dependent on the detergent concentration and more than 80% of naphthalene-1-acetic acid (NAA)-binding activity was recovered by an optimum concentration of 0.2%. The solubilized MABP was highly heat-unstable and sensitive to protease. The properties of MABP (affinity, temperature dependence, pH optimum, and analog specificity for auxin binding) did not significantly change after solubilization, e.g. the solubilized MABP showed no or very low levels of NAA-binding at 0 to 4 degrees C but showed a high-affinity binding (dissociation constant K(d) = 2.7 +/- 0.3 x 10(-7)m) at 25 degrees C at an optimum pH of 5.0. NAA-binding of the solubilized MABP proceeded very slowly, i.e. a time of half-maximum binding was at least 15 minutes, although the solubilized MABP showed higher rates of association (k(1) = 1.3 versus 0.9 x 10(5)m(-1) min(-1)) and dissociation (k(-1) = 2.2 versus 1.6 x 10(-2) min(-1)) with NAA than the bound MABP. These results show that specific, saturable, and reversible auxin binding to MABP from dicotyledonous N. tabacum differs from that from monocotyledonous Zea mays, and confirm that MABP is distinct from a soluble auxin-binding protein which also is present in N. tabacum.

Journal Article↗
PubMed1988

Correlation between Auxin Resistance and the Lack of a Membrane-Bound Auxin Binding Protein and a Root-Specific Peroxidase in Nicotiana tabacum.

The levels of a membrane-bound auxin binding protein (MABP) and a root-specific peroxidase (RSP) were studied in several tobacco (Nicotiana tabacum L.) cell lines including an auxin-resistant variant. Groups of cell lines were distinguished which behaved differentially with respect to MABP and RSP depending on the hormonal composition of the medium. In cell lines in which there existed a correlation between the presence or absence of MABP and that of RSP both phenotypes were expressed if kinetin (1-2 micromolar) was supplied. In contrast, neither MABP nor RSP could be detected under any hormonal conditions tested in the auxin-resistant variant which retains the ability to differentiate shoots but lacks the ability to differentiate roots. About an eightfold increase in the concentration of MABP and a dramatic increase in the activity of RSP occurred in a transformant by a mutant strain of Agrobacterium tumefaciens lacking an intact cytokinin gene when it was grown on medium containing 1 to 2 micromolar kinetin. A correlation between auxin resistance and the lack of MABP and RSP suggests that MABP might be involved in auxin-mediated root differentiation in tobacco.

Journal Article↗
PubMed1988

Modulation of cyclic AMP and autoregulation of renal blood flow, analysed by the use of forskolin and 1-methyl-3-isobutylxanthine.

We have examined the effects of forskolin and 1-methyl-3-isobutylxanthine (IBMX) in relation to cyclic (c)AMP metabolism and renal blood flow autoregulation in anaesthetized dogs. Control observations usually showed excellent autoregulation of renal blood flow over the renal perfusion pressure range of 120-200 mmHg, when the perfusion pressure was changed, stepwise, between 60 and 200 mmHg. Renal blood flow was increased by the infusion of forskolin (10 micrograms min-1) and IBMX (100 micrograms min-1) at the basal perfusion pressure of 100 mmHg, and maintained an increased level while the infusion was continued. Forskolin and IBMX did not inhibit autoregulation, though they shifted the perfusion pressure range evoking autoregulation. These data indicate that vasodilators which may produce the activity through modulating the cAMP level in vascular smooth muscle do not influence the establishment of autoregulation of renal blood flow.

1-Methyl-3-isobutylxanthine↗
PubMed1988

Cardiotonic activity of 5-methyl-6-(4-pyridyl)-2H-1,4-thiazin-3(4H)-one hydrochloride (ZSY-27).

Cardiotonic activity of a new, non-catecholamine and non-glycoside positive inotropic agent, 5-methyl-6-(4-pyridyl)-2H-1,4-thiazin-3(4H)-one hydrochloride (ZSY-27), was investigated in isolated guinea pig left atria, cat right ventricular papillary muscle and cross-circulated excised dog papillary muscle preparations, and in anesthetized open-chest dogs. In electrically driven guinea pig left atria and cat papillary muscle preparations, ZSY-27 (3 x 10(-6)-10(-4) M) increased the developed tension in a concentration-related manner. The positive inotropic effect of ZSY-27 was not blocked by propranolol (3 x 10(-8) M) in the guinea pig atria, but was significantly inhibited by carbachol (5 x 10(-6) M) in cat papillary muscle preparations. The positive inotropic effect of ZSY-27 was comparable to that of milrinone in guinea pig atria. ZSY-27 (0.01-3 mg) increased dose-dependently the developed tension in cross-circulated excised dog papillary muscle preparations as well. In anesthetized dogs, ZSY-27 (0.03-1 mg/kg, i.v.) produced a dose-dependent increase in left ventricular contractile force and a decrease in blood pressure, while the increase in heart rate was relatively small. The pharmacological profile of ZSY-27 in anesthetized dogs was similar to that of milrinone. These results suggest that ZSY-27 is potent cardiotonic agent with vasodilator activity and its effect may be partially due to an increase in the intracellular adenosine 3',5'-cyclic monophosphate level.

Animals↗
PubMed1988

Different interaction of bepridil and diltiazem with BAY K 8644 in the abolition of autoregulation of renal blood flow.

The effect of bepridil and diltiazem on autoregulation of renal blood flow was examined in connection with interaction of BAY K 8644 in perfused kidney of anesthetized dogs. When the perfusion pressure was changed stepwise over the range between 60 and 200 mm Hg, renal blood flow remained nearly constant between 100 and 200 mm Hg. Intra-arterial infusion of diltiazem (50 microgram/min) or bepridil (1 mg/min) increased renal blood flow at perfusion pressure above 100 mm Hg and completely inhibited renal autoregulation. Simultaneous infusion of 5 microgram/min of BAY K 8644 with diltiazem antagonized both the increase of renal blood flow and the impairment of autoregulation, whereas simultaneous infusion of BAY K 8644 (5 micrograms/min) could not block the impairment of renal autoregulation induced by bepridil. These results show that the inhibitory effect of bepridil on autoregulation of renal blood flow is due to some mechanism other than Ca channel blocking action in renal vasculature.

3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethy↗
PubMed1988

Functional significance of subtypes of 5-HT receptors in the rat spinal reflex pathway.

1. The functional significance of subtypes of 5-hydroxytryptamine (5-HT) receptors was studied in the rat spinal reflex pathway. 2. Ketanserin had no effect on the mono- (MSR) or polysynaptic reflex (PSR) in spinal rats, but decreased the PSR in intact rats. 3. 8-Hydroxy-2-(di-n-propylamino)tetralin (8-OH-DPAT) and 5-methoxy-N,N-dimethyltryptamine (5-MeODMT) decreased the MSR and increased the PSR in spinal rats. 4. Ketanserin antagonized the effects of 5-MeODMT without antagonizing the effects of 8-OH-DPAT. 5. Cinanserin had similar effects to those of ketanserin. 6. These results suggest that both 5-HT1A and 5-HT2 receptors mediate MSR inhibition and PSR augmentation in the spinal reflexes of spinal rats, and that the 5-HT2 receptor has a supraspinal tonic excitatory influence on the PSR in intact rats.

5,6-Dihydroxytryptamine↗
PubMed1988

Inhibitory effect of phencyclidine on rat spinal reflexes.

1. The effects of phencyclidine (PCP) on spinal reflexes and the excitability of motoneuron somata were studied in rats. 2. PCP decreased both the monosynaptic reflex (MSR) and the polysynaptic reflex (PSR) in spinal rats as well as in intact rats. 3. The effects of PCP were not antagonized by monoaminergic and cholinergic antagonists. 4. A low dose of PCP antagonized the PSR augmentation but not the MSR augmentation caused by N-methyl-D-aspartate (NMDA). 5. In the excitability test, PCP decreased not only the monosynaptic response but also the excitability of motoneuron somata. 6. These results suggest that the inhibitory effects of PCP on spinal reflexes are not due to mediation of the monoaminergic and cholinergic systems, but partly due to its blockade of NMDA-type receptors and also to a hyperpolarizing action or a membrane-stabilizing action on the motoneuron soma.

Animals↗
PubMed1988

Egocenter location in children enucleated at an early age.

In normal binocular vision the origin of judgments of visual direction is the egocenter located on the median plane of the head, midway between the two eyes. For children enucleated at an early age there is abrupt cessation of binocular input to the visual cortex. We evaluated the effect of early removal of one eye on the location of the egocenter, comparing the results in enucleated children to normal binocular children tested monocularly. We found a significant shift of the egocenter towards the remaining eye of the enucleates that was unrelated to the age at enucleation. At least up to 4 years of age, egocenter location is plastic and can be modified by the complete monocularity imposed by enucleation.

Adolescent↗
PubMed1987

Integration of porin synthesized in vitro into outer mitochondrial membranes.

Porin, an intrinsic protein of outer mitochondrial membranes of rat liver, was synthesized in vitro in a cell-free in a cell-free translation system with rat liver RNA. The apparent molecular mass of porin synthesized in vitro was the same as that of its mature form (34 kDa). This porin was post-translationally integrated into the outer membrane of rat liver mitochondria when the cell-free translation products were incubated with mitochondria at 30 degrees C even in the presence of a protonophore (carbonyl cyanide m-chlorophenylhydrazone). Therefore, the integration of porin seemed to proceed energy-independently as reported by Freitag et al. [(1982) Eur. J. Biochem. 126, 197-202]. Its integration seemed, however, to require the participation of the inner membrane, since porin was not integrated when isolated outer mitochondrial membranes alone were incubated with the translation products. Porin in the cell-free translation products bound to the outside of the outer mitochondrial membrane when incubated with intact mitochondria at 0 degrees C for 5 min. When the incubation period at 0 degrees C was prolonged to 60 min, this porin was found in the inner membrane fraction, which contained monoamine oxidase, suggesting that porin might bind to a specific site on the outer membrane in contact or fused with the inner membrane (a so-called OM-IM site). This porin bound to the OM-IM site was integrated into the outer membrane when the membrane fraction was incubated at 30 degrees C for 60 min. These observations suggest that porin bound to the outside of the outer mitochondrial membrane is integrated into the outer membrane at the OM-IM site by some temperature-dependent process(es).

Animals↗
PubMed1987

Enhancement of recurrent inhibition of the spinal monosynaptic reflex by preceding stimulation of the medullary raphé in rats.

Recurrent inhibition of the spinal monosynaptic reflex (MSR) elicited by conditioning stimulation of the ventral root in anesthetized rats was weaker than both the recurrent inhibition of the disynaptic reflex and the inhibition of the MSR elicited by conditioning stimulation of the adjacent dorsal root. Among these 3 inhibitions, the recurrent inhibition of the MSR was enhanced to a markedly greater extent by a preceding stimulation of the medullary raphé nucleus than were the other inhibitions. The magnitude of the enhancement of the recurrent inhibition of MSR also was much greater when the medullary stimulation was delivered 20 ms prior to the ventral root activation, as compared with a 30-ms interval. Recurrent inhibition of the MSR was enhanced by intravenous injection of lysergic acid diethylamide (LSD); however, the enhanced effect on recurrent inhibition elicited by stimulation of the raphé nucleus was not attenuated by the drug. These results suggest that there is a non-serotonergic, descending pathway which is capable of modulating motor output solely by means of recurrent inhibition of the MSR.

Animals↗
PubMed1987

Sensitivity of spinal reflexes to TRH and 5-HT in 5,6-dihydroxytryptamine-treated rats.

Destruction of descending serotonergic nerve terminals containing thyrotropin-releasing hormone (TRH) was affected in rats by the intracisternal injection of 5,6-dihydroxytryptamine (5,6-DHT) two weeks before subsequent experiments. Although the level of TRH in the lumbar enlargement was significantly reduced in 5,6-DHT-treated rats, the effects of TRH on the monosynaptic reflex (MSR) and the polysynaptic reflex (PSR) in these rats were no different from those in control rats. MSR inhibition by 5-methoxy-N,N-dimethyltryptamine (5-MeODMT) was attenuated by 5,6-DHT treatment although there was no obvious difference in the effects of 5-MeODMT on the PSR between 5,6-DHT-treated and control rats. In 5,6-DHT-treated rats, L-5-hydroxytryptophan (5-HTP) markedly decreased the MSR and increased the PSR although the same doses of 5-HTP did not produce any effects on either the MSR or the PSR in control rats. In control rats, after administration of imipramine or clorgyline, 5-HTP produced effects similar to those observed in 5,6-DHT-treated rats. These results suggest that the supersensitivity to 5-HTP in 5,6-DHT-treated rats is due to a lack of 5-hydroxytryptamine (5-HT) uptake into 5-HT-containing nerve terminals rather than to a change in 5-HT receptors.

5,6-Dihydroxytryptamine↗
PubMed1987

Direct evidence for the interaction between papaverine and alpha 2-adrenergic receptors in canine platelets.

The effects of papaverine on specific [3H]-yohimbine binding to canine platelet alpha 2-adrenergic receptors and on the platelet aggregation were assessed and compared with those of verapamil. Both compounds concentration-dependently inhibited [3H]-yohimbine binding with KI values for respective compounds of 0.39 +/- 0.05 microM (n = 3) and 15 +/- 0.19 microM (n = 3). In the presence of either compound KD values in Scatchard analysis of the equilibrium ligand binding increased in concentration-dependent manner, whereas Bmax did not change, indicating competitive inhibition of the ligand binding by these compounds. (-)-Epinephrine (3 microM) potentiation of adenosine diphosphate (ADP, 0.1 microM) aggregation was inhibited by papaverine with IC50 of 11 +/- 3.6 microM (n = 4). In the same experiments verapamil inhibited the platelet aggregation with lower IC50 (3.1 +/- 0.87 microM, n = 4) in comparison with that for papaverine. These results suggest that papaverine, like verapamil, inhibits physiological response of canine platelets through alpha-adrenergic receptor stimulation by direct interaction with the receptors.

Animals↗