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Y Oda

Publications and source records attributed to Y Oda.

At least 631 records · Page 35Linked to original sources
PubMed1984

[Sustained-release pellet of vasodilators--basic experiment].

We examined the efficacy of slow-release, and prolonged diffusion silicone pellets mixed with papaverine hydrochloride in the treatment of cerebral vasospasms following subarachnoid hemorrhage. In addition the diffusion of the other vasodilating agents (diltiazem and nicardipine) into the saline solution using the same silicone materials was also investigated. Papaverine hydrochloride was either packed in silicone tubes (packed type) or polymerized with silicone elastomer, Silastic MDX-4-4210 (solid type). The solid type pellet is cylindrical-(diameter 3 mm, length 30 mm) and contains 40 w/v% of pure powder of papaverine. The amount of the delivered drug was measured for 5 weeks at 37 degrees C and at room temperature. The diffusion rate of the solid type pellet was about 5 times higher than that of the packed one. The diffusion rates of both types of pellets were about 10 times higher at 37 degrees C than at room temperature. The cummulative amount of the delivered drug from the solid type pellet was 37.1% of the initial packed volume at 37 degrees C in the first 3 weeks. The diffusion of diltiazem and nicardipine which were polymerized 30 w/v% in silicone elastomer was observed for 3 weeks at 37 degrees C only in solid type pellet form. The diffusion rate was measured under the condition of either continuous shaking or standing. The results showed the same diffusion rates for diltiazem and nicardipine, with no difference in diffusion rate between the "shaking" and "standing" groups. The diffusion rate showed inverse exponential curves, and was 5-20 X 10(-5)/day/mm2 of initial volume until 5 days.(ABSTRACT TRUNCATED AT 250 WORDS)

Delayed-Action Preparations↗
PubMed1984

[Contrast material with oxygenated Fluosol-DA, 20 for the protection against complications of catheter cerebral angiography].

Although computed tomography may change the criteria of cerebral angiography in neurosurgery, the neurosurgeon still requires angiographic confirmation of vascular anatomy at the operative sites, and catheterization for intra-luminal constructive surgery is also seeing progress. Cerebral angiography is a rather safe procedure; however, persistent serious neurological deficits and fatal complications are occasionally reported. The mechanisms of these complications are considered to be due to mechanically dislodged fragments of clots and/or atheroma, or direct endothelial damage by the catheter, contrast agents toxicity to brain tissue, anoxic neurocytologic injury due to the disturbance of the blood flow. Fluosol-DA (a type of perfluorochemical) has a potent oxygen-carrying capacity and has been safely used in humans as an artificial blood substitute. Meglumine diatrizoate (65% Angiografin) has not lost the x-ray opacification faculty in cerebral angiography by mixing with oxygenated Fluosol-DA, 20 up to 30 vol % of the latter in clinical use. In animal experiments, from 0.25 to 4 ml/kg of Angiografin-65 or Angiografin-65 with oxygenated Fluosol-DA, 20 were injected into the internal carotid artery of mongrel dogs. When 2.0 ml/kg of Angiografin-65 was injected into the carotid artery, remarkable arrhythmia was observed for 7.5 seconds. Blood pressure dropped 28.3 mmHg for 20.2 seconds; thereafter, it increased 25 mmHg in rebound for 15 seconds. Intracranial pressure increased 5 mmHg for 35 seconds, respiratory disturbance continued for 22.6 seconds. When a 20 vol % mixture of Fluosol-DA, 20 with Angiografin-65 was applied, these adverse reactions were markedly reduced.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1984

Mechanisms of specific change by estradiol in sensitivity of rat uterus to serotonin.

The sensitivity (contractile response) to serotonin (5-HT) of the isolated rat uterus was increased either during estrus or by administration of estradiol to ovariectomized rats. These increases in sensitivity to 5-HT were specific, because the sensitivities to acetylcholine and oxytocin were not influenced in either case. Pargyline (10(-5) M), an inhibitor of monoamine oxidase, did not affect the contractile responses to 5-HT, acetylcholine and oxytocin of uterus from ovariectomized rats. The monoamine oxidase activities in 100,000 X g precipitates and supernatants of homogenates for uteri from ovariectomized rats were either increased or unchanged by administration of estradiol. The contractile response to 5-HT of the uterus of untreated ovariectomized rats was not affected by chlorimipramine at 10(-6) M, a concentration that inhibits 5-HT uptake. Administration of estradiol increased significantly the number of [3H]spiroperidol binding sites (5-HT receptors) from 0.56 +/- 0.04 to 1.23 +/- 0.11 pmol/mg of protein, but did not change the apparent affinity of 5-HT receptors. Administration of estradiol did not change the dissociation constant or number of binding sites for [3H]quinuclidinyl benzilate (muscarinic acetylcholine receptors) significantly. These results indicate that the specific increase in sensitivity to 5-HT on administration of estradiol is due to change in the number of 5-HT receptors, but not to change in 5-HT uptake or in metabolic degradation of 5-HT.

Animals↗
PubMed1984

[Effects of interferon and its inducers on neutrophil chemiluminescence].

In order to evaluate effects of interferon (IFN) and its inducers on neutrophil functions, neutrophil chemiluminescence (ChL) was assayed in 12 patients treated with IFN (human lymphoblastoid interferon, 3.0 X 10(6) units/day i.m. daily) or Ge-132 (2,250 mg/day p.o. daily). The peak levels of neutrophil ChL, assayed one week after the initiation of treatment, were increased in comparison to those before treatment, but one month after treatment they were decreased to pretreatment levels in spite of the daily administration of the agent. On the basis of these results, it was concluded that IFN and Ge-132 enhanced the host defence mechanism including the activation of neutrophils, which appeared at the early phase of the host reaction.

Adenocarcinoma↗
PubMed1983

Purification and characterization of beta-galactoside-binding lectin from chick embryonic skin.

Lectin activity was found in tarsometatarsal skin of chick embryo. It was specific for beta-linked galactosyl residues and required a thiol-reducing agent for hemagglutination activity. The lectin was extracted from dermis and epidermis (skin) with lactose and purified to apparent homogeneity by affinity chromatography on asialofetuin-Sepharose. Examination of their biochemical properties showed that although dermis and epidermis develop from different origins, they contain the same lectin. The apparent subunit Mr of lectin was 14000 and its isoelectric point was 7.0. Under non-dissociating conditions, the lectin exists mainly as a dimer. Radioimmunoassay showed that this skin-type lectin is present in many tissues including skin, muscle, bone, eye, heart, liver and brain at various developmental stages. A wide distribution and a marked change in its content during development strongly suggest that the lectin might have a fundamental role in cellular function, embryonic development and tissue differentiation.

Amino Acids↗
PubMed1983

Increase of serotonin receptors in rat uterus induced by estradiol.

[3H]Spiroperidol was used to label uterine membrane-binding sites that have the characteristics expected of serotonergic receptors. The characteristics of specific [3H]spiroperidol binding to the uterine membrane of 17 beta-estradiol-3-benzoate-treated ovariectomized rats were studied. The specific [3H]spiroperidol binding was rapid and reversible, and the half-maximal saturation, taken as the apparent dissociation constant (KD) for [3H]spiroperidol, was 5.16 +/- 0.24 (n = 12) nM [3H]spiroperidol. Scatchard plots of saturation curves of the specific [3H]spiroperidol binding were convex and the Hill coefficient was 2.06 +/- 0.11 (n = 12). Cinanserin, mianserin, metergoline (which are serotonergic antagonists), and serotonin (5-HT) inhibited the [3H]spiroperidol binding with apparent Ki values of 21.2, 14.1, 14.1, and 176.5 microM, respectively. Concentrations of 1 mM sulpiride (a dopaminergic antagonist) and dopamine reduced [3H]spiroperidol binding only 26 and 23%, respectively. 1 mM GTP reduced the potency of 5-HT (10(-6) - 10(-3) M) to displace bound [3H]spiroperidol. The uterine membranes were treated with various enzymes and protein-modifying reagents, and binding studies on the treated uterine membranes showed that protein(s), phospholipids, and N-acetyl-neuraminic acid in uterine membranes were important as specific binding sites of [3H]spiroperidol. Measurement of the specific binding of [3H]spiroperidol to uterine membranes from untreated and estradiol-treated ovariectomized rats showed that estradiol significantly increased the number of specific binding sites of [3H]spiroperidol, but did not change the apparent affinity of specific [3H]spiroperidol binding. Estradiol also did not change the dissociation constant or the number of binding sites for [3H]3-quinuclidinyl benzilate, which binds to muscarinic acetylcholine receptors. These findings suggest that [3H]spiroperidol mainly binds to 5-HT receptors in the uterine membrane of estradiol-treated ovariectomized rats. The finding that administration of estradiol significantly increased the number of [3H]spiroperidol-binding sites is consistent with the specific increase in the contractile response to 5-HT observed in isolated uterus from ovariectomized rats treated with estradiol.

Animals↗
PubMed1983

Properties of cerebello-precerebellar reverberating circuits.

Intracellular recordings were made from neurons of the red nucleus (RN) in cats where the cerebellar cortical effects were removed by chronic ablation of the intermediate part of the anterior lobe of the cerebellum. A prolonged depolarization could be elicited by stimulating the nucleus interpositus (IP) of the cerebellum, nucleus reticularis tegmenti pontis (NRTP) and the nucleus reticularis paramedianus (PMRN). This prolonged depolarization was abolished after cooling the inferior and middle cerebellar peduncles and persisted after ablation of the cerebral sensorimotor cortex. The prolonged depolarization was also recorded intracellularly from IP neurons. It was concluded that the prolonged depolarization set up in RN neurons is due to the repetitive discharges of IP neurons which produces tonic bombardment onto RN cells. The mechanisms of the repetitive discharges of IP neurons are considered to be due to impulse reverberation via the IP. The dynamic properties of the reverberating circuits were characterized by regenerative behavior. Above and below threshold, there were two states, the excited state where many constituent neurons were active, and the resting state where all neurons were inactive. It was found that cats with chronically stimulated cerebral peduncle (CP), and tested in an acute experiment, showed sometimes effective for inducing the prolonged depolarization and repetitive discharges of RN neurons by stimulation of IP. The prolonged depolarization thus produced could be reversibly abolished by cooling the middle and inferior cerebellar peduncles. The possible constituent neurons of the reverberating circuits were investigated in light of previous physiological investigations of stimulating the NRTP, PMRN, nucleus reticularis lateralis (LRN), nucleus olivaris inferior (IO) and recording EPSPs in RN cells. The RN cells receive axon reflex activation from NRTP and PMRN, and disynaptic excitation from NRTP, PMRN, LRN and IO. Based on these and other available data, the components of the cerebello-precerebellar reverberating circuits are discussed.

Animals↗
PubMed1983

Effects of a transfusion with a blood substitute (Fluosol-DA, 20%). Part II: Human cerebral blood flow.

In 24 patients suffering from cerebrovascular diseases, alteration of the cerebral blood flow was investigated by means of the 133Xe clearance technique before and after the intravenous infusion of perfluorochemical suspension (Fluosol-DA, 20%, 10 ml/kg). Since perfluorochemicals exhibit high solubilities for not only oxygen but other kinds of gases, the partition coefficient of Xe (lambda tb) is considered to change depending on the amount of perfluorochemicals contained in the blood (Fct). The solubilities of Xe in the perfluorochemicals contained in the solution were then measured by gas chromatography to obtain an equation for lambda tb: lambda tb = 1.50/(Hct/100 + 12.48Fct/100 + 0.95). The cerebral blood flow was found to increase significantly by 10.1% in the lesional hemisphere and by 10.8% in the healthy one. The cortical small artery with a diameter between 0.1 and 0.2 mm appeared to dilate by 13% after its administration. From these results, the decrease of blood viscosity and some vasodilating effect of the solution might be responsible for the increase of the cerebral blood flow.

Blood Substitutes↗
PubMed1983

Characterization of a Saccharomyces cerevisiae mutant, N22, defective in ergosterol synthesis and preparation of [28-14C]ergosta-5,7-dien-3 beta-ol with the mutant.

Analysis of sterols was made with a Saccharomyces cerevisiae mutant, N22, which was resistant to nystatin and defective in ergosterol synthesis, and with its parent strain, M10 (haploid type, methionineless, petite). The main sterol of M10 was ergosterol, whereas that of N22 was ergosta-5,7-dien-3 beta-ol. A small amount of ergosterol was found also in N22. This indicates that the delta 22-desaturation reaction in N22 is blocked, though not completely. Ergosta-5,8-dien-3 beta-ol, an unusual sterol, was detected in N22 but not in M10. Variations in the amounts and compositions of free and esterified sterols of both strains were examined during cultivation and the subsequent aerobic adaptation. The contents of free sterols, which were mostly composed of the respective main sterols of both strains, did not change markedly. In contrast, the contents and compositions of esterified sterols of both strains varied depending on the growth conditions. When the cells of both strains were aerobically adapted, the total contents of esterified sterols increase, as did, as the intermediate sterols. Upon aerobic adaptation in the presence of [methyl-14C]methionine, [28-14C]ergosta-5,7-dien-3 beta-ol accumulated markedly in N22 cells. Using this mutant, we devised a convenient method for preparation of the radioactive sterol in high yield.

Chemical Phenomena↗
PubMed1983

An ultrastructural study on periductal elastosis in human breast tumors.

An ultrastructural study on elastosis of human breast tumors was made with special attention to the periductal elastosis and the cell responsible for elastic fiber formation. The elastosis was found prominently in scirrhous type of duct carcinoma. In the area of mild periductal elastosis, the elastic fibers with many microfibrils and a tiny central elastin were seen around the periductal fibroblasts which were characterized by attenuated cytoplasms with aggregates of microfilaments and slightly developed rough endoplasmic reticulum. With the thickening of the periductal wall, such an area was replaced by abundant mature elastic fibers with peripheral microfibrils and a few intervening ordinary fibroblasts. Therefore, it was suggested that the periductal fibroblasts which transformed into ordinary fibroblasts during the development of elastosis were primarily concerned with the elastic fiber formation. In the interlobular tissue in which both fibroblasts and myofibroblasts were present, the elastic fibers were larger than those of the periductal area and had less microfibrils in their periphery. The relationship between microfibrils and elastin during the early elastosis, maturation process of the elastic fibers, and cell modulation of the fibroblasts in the breast elastosis were discussed.

Adenofibroma↗
PubMed1983

Epidural hematomas of the posterior fossa in children.

The authors report 3 cases of epidural hematoma of the posterior fossa in children. The clinical signs and symptoms are discussed. Onset of symptoms is not necessarily acute. The radiological findings are discussed. Epidural hematomas of the posterior fossa in children have a tendency to liquefy earlier than supratentorial hematomas. We emphasize the value of computed tomography for the diagnosis of epidural hematoma of the posterior fossa. One should keep in mind the possibility of the presence of an epidural hematoma of the posterior fossa in the treatment of head injury in children, even in the case of a minor head injury.

Cerebral Angiography↗