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Biomedical subjects

Y Masuda

Publications and source records attributed to Y Masuda.

1,116 records · Page 62Linked to original sources
PubMedDate not supplied

Alpha 2-adrenoceptor activity induces the antidepressant-like glycolipid in mouse forced swimming.

Antidepressants show an antidepressive-like behavioral effect on mouse forced swimming via induction of GalNAc alpha 1-3GalNAc-lipid. In order to detect the mechanisms of the neuron receptor activities on the effect, the glycolipid reactivities in the serum induced by tandospirone, a specific 5-HT1A receptor agonist, and clonidine, a specific alpha 2-adrenoceptor agonist, were investigated. Both of these agonists showed dose-dependent behavioral effects which were decreased by pretreatment with yohimbine, a specific alpha 2-adrenoceptor antagonist. The glycolipid reactivities corresponded with the effects. These present findings strongly suggest that alpha 2-adrenoceptor activity in the brain mediates the induction of the antidepressant glycolipid in the forced swimming test.

Adrenergic alpha-Agonists↗
PubMedDate not supplied

Behavioral effect of herbal glycoside in the forced swimming test.

We investigated the behavioral effects of Chinese herbal medicines in the forced swimming test. One of these medicines, Kami-shoyo-san, induced an antidepressive climbing behavior in mice. An effective substance detected to be an O-linked glycoside with the sugar chain structure GalNAc alpha 1-3GalNAc was separated. The behavioral effect was dose-dependently decreased by the dopamine 2 antagonist sulpiride, but not by the dopamine 1 antagonist SCH-233960. Investigated Chinese herbal medicines, including Kami-shoyo-san, have been used for human depression. These facts suggest that glycoside is one of the antidepressant-like substances of Chinese herbal medicines.

Animals↗
PubMedDate not supplied

A glycoside of Nicotina tabacum affects mouse dopaminergic behavior.

Climbing in the forced swimming test is considered a dopaminergic-specific behavior. A substance of Nicotina tabacum affecting dopamine neuronal activity was investigated using the mouse behavioral system. The substance was found to be a glycoside with the peripheral sugar chain structures Fuc alpha 1-2Gal, Gal beta 1-4GlcNAc and GalNAc alpha 1-3GalNAc and with basic polymannoses. The glycoside dose-dependently increased behavior via D2 neuronal activity, but not D1 activity. This suggests that smoking can affect human brain function not only via the nicotinic cholinergic neuron, but also via the D2 neuron.

Animals↗
PubMedDate not supplied

Changes in the rheological properties of the cell wall of plant seedlings under simulated microgravity conditions.

In this review article, we discuss the changes in the mechanical properties of the primary cell wall of different organs of several species of plant seedlings grown under simulated microgravity conditions. We compared growth and tropistic responses of these organs growing under different microgravity conditions, namely: 1) 3-D clinostat (three-dimensional clinostat with two axes); 2) water-submergence for rice seedlings, and 3) for comparison, an accelerated gravity using a specifically designed centrifuge. We measured the minimum stress-relaxation time as the parameter representing the mechanical property of the cell wall. We also measured extensiblity, in mm/g. The 3-D clinostat condition disturbed the normal gravitropic response of organs but affected growth rate and mechanical properties of the cell wall very little. Water-submergence of rice seedlings caused an acceleration of coleoptile elongation in the dark and caused a marked change in the mechanical property of the cell wall. However, the additional gravity of 30-135 xg showed only a small effect on growth and the mechanical property of the cell wall.

Biomechanical Phenomena↗
PubMedDate not supplied

Analysis of caspases that are activated during apoptosis in leukemia U937 cells in response to geranylgeraniol.

Affinity labeling showed that active caspases with molecular masses of 20 kDa, 19 kDa, and 17 kDa were formed upon treatment of human leukemia U937 cells with GGO. These caspases are quite similar to those activated by treatments with other apoptosis-inducers, such as VP16 and camptothecin, suggesting that similar caspases, such as caspases 3 and 6, are activated during apoptosis in U937 cells that is induced by a variety of apoptosis-inducing stimuli. An inhibitor of caspases, Z-Asp-CH2DCB, inhibited DNA fragmentation in response to GGO in vivo by blocking the cleavage of 20-kDa to 17-kDa peptides. This cleavage is catalyzed by caspase 3 itself or by a caspase-3-like protease. In contrast, other inhibitors of caspases such as Z-DEVD-FMK and Z-VAD-FMK, inhibited the processing of the caspase 3 precursor p32 to 20-kDa and 17-kDa peptides, a result which suggests that these inhibitors inhibited other upstream caspases. Treatment of U937 cells with GGO resulted in the release of cytochrome c from mitochondria prior to DNA fragmentation and the release of cytochrome c was inhibited by Zn2+ ions and by a chelator of Ca2+ ions but not by inhibitors of caspases such as Z-Asp-CH2DCB or Z-VAD-FMK. These results suggest that intracellular free Ca2+ ions, and some caspases that are inhibited by Zn2+ ions, but not by Z-Asp-CH2DCB or Z-VAD-FMK are necessary for the release of cytochrome c that is caused by the treatment with GGO.

Affinity Labels↗
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Another anti-allergic mechanism: antibody IgE deglycosylation induced by a substance extracted from human urine.

Enzymically-deglycosylated antibody IgE lost its allergic activity in mouse systemic anaphylaxis, though the IgE kept its antibody activity. IgE antibody obtained from mice treated with a substance extracted from human urine was deglycosylated. This IgE also lost the allergic activity on the systemic anaphylaxis but kept its antibody activity. These findings strongly suggest that glycosylation of IgE has a close relation to the binding of the Fc receptor and that humans have another antiallergic mechanism: in vivo IgE antibody deglycosylation induced by the substance.

Allergens↗
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Vasorelaxing and receptor binding properties of NZ-105, a novel dihydropyridine derivative, in isolated rabbit aorta.

The vasorelaxing and dihydropyridine receptor binding properties of NZ-105, a new dihydropyridine derivative, were studied using isolated rabbit aorta, and compared with those of nicardipine, nifedipine and diltiazem. NZ-105 (3 x 10(-10)-3 x 10(-9) M), nicardipine (3 x 10(-10), 10(-9) M), and diltiazem (3 x 10(-7), 10(-6) M) selectively relaxed aortic strips precontracted with high-K+ solution (50 mM) with little effect on strips precontracted with phenylephrine (10(-5) M) or clonidine (10(-6) M). The relaxation produced by NZ-105 was of very slow onset, and no recovery was observed after a 2 hr washout with high-K+ or normal bathing solution. NZ-105 (3 x 10(-10)-3 x 10(-9) M) caused a non-parallel depression of the concentration-response curve for the CaCl2-induced contraction in high-K(+)-depolarized rabbit aorta, whereas nicardipine (10(-10), 3 x 10(-10) M), nifedipine (10(-9), 3 x 10(-9) M) and diltiazem (10(-7), 3 x 10(-7) M) all produced a concentration-related rightward displacement of the curve. The depression induced by NZ-105, but not by nicardipine, became greater as the period of preincubation with the drug was prolonged. NZ-105, nicardipine and diltiazem, at the very high concentration of 10(-6) M, caused a slight and noncompetitive inhibition of the concentration-response curves for norepinephrine, prostaglandin F2 alpha, angiotensin II and 5-hydroxytryptamine. NZ-105 displaced 3H-nitrendipine binding to rabbit aortic membranes in a manner similar to that of nicardipine and nifedipine, and this was also incubation time-dependent. These results indicate that NZ-105 possesses selective calcium antagonist properties, with respect to the rabbit isolated vascular smooth muscle, which are of very slow onset and long-lasting. The slow onset of the vasorelaxation may be due to a slow association rate to dihydropyridine receptors. These pharmacological properties of NZ-105 may, at least in part, be responsible for the slow onset and long duration of its antihypertensive action in vivo.

Angiotensin II↗
PubMedDate not supplied

Cardiac and vascular effects of NZ-105, a novel dihydropyridine derivative, in vitro.

The cardiovascular selectivity of NZ-105, a novel dihydropyridine derivative, was studied in vitro in comparison with nicardipine and other calcium antagonists. NZ-105 and nicardipine (10(-9), 10(-8) M) decreased the spontaneous contraction rate of the isolated guinea-pig right atrium. On the other hand, NZ-105, even at concentrations as high as 10(-6) M, slightly diminished the contractile force of the electrically driven left atrium, while nicardipine strongly and dose-dependently decreased the contractile force at a concentration of 10(-7) M by 39.9% and at 10(-6) M by 72.1%. NZ-105, nicardipine and diltiazem, at concentrations below 10(-6) M, caused no or only a slight depression of isoproterenol-induced increases in the contractile force of the driven left atrium. In left atrium partially depolarized with high K+ (22 mM) in the presence of 10(-6) M of isoproterenol, NZ-105 (10(-8)-10(-6) M), nicardipine (10(-9)-10(-7) M) and diltiazem (10(-7), 10(-6) M) produced both a concentration-related displacement of the concentration-response curves for CaCl2 to the right and a depression of the maximum response to CaCl2. In various rabbit blood vessels depolarized with high K+ (100 mM) (coronary, superior mesenteric, renal and femoral arteries and saphenous vein). NZ-105 (3 x 10(-10)-10(-8) M) caused a non-parallel depression of the concentration-response curves for CaCl2-induced contractions. The calcium-antagonizing effect of NZ-105 was strongest in the basilar artery. NZ-105 displaced the [3H]-nitrendipine binding to rabbit cardiac and aortic membranes in a manner similar to nicardipine and nifedipine. The Ki values of these compounds, with respect to cardiac membranes, were several times larger than in the case of aortic membranes. The Ki value of NZ-105, but not of nicardipine, grew smaller as the preincubation period with the drug increased. These findings indicate that NZ-105 possesses selective calcium-antagonizing properties in vascular smooth muscle, especially in the basilar artery, when compared with cardiac muscle. The negative chronotropic action of NZ-105 was more potent than its inotropic action. On the basis of these pharmacological properties, NZ-105 is considered to be a useful drug for the treatment of cardiovascular disorders.

Animals↗
PubMedDate not supplied

Measurements of the effect of dipyridamole on regional myocardial blood flow with positron emission tomography and the first-pass flow model.

We assessed percent changes of regional myocardial blood flow (RMBF) after infusion of dipyridamole (0.56 mg/kg) with dynamic N-13 ammonia PET and the first-pass flow model. Positron emission tomography (PET) was performed at rest and after infusion of dipyridamole in 17 participants [five normal subjects, five patients with hypertrophic cardiomyopathy (HCM), and seven patients with coronary artery disease]. Dipyridamole increased RMBF 126 +/- 69% (mean +/- SD) in normal subjects and 55 +/- 43% in the patients with HCM. In the cases of coronary artery disease, the percent changes of RMBF were +19 +/- 19% in ischemic areas and +76 +/- 23% in nonischemic areas. These results demonstrate that N-13 ammonia dynamic PET study is useful in assessing the percent changes of RMBF induced by dipyridamole infusion.

Adult↗
PubMedDate not supplied

Antihypertensive and diuretic effects of NZ-105, a novel dihydropyridine derivative.

Studies on the antihypertensive and diuretic actions of NZ-105, a new dihydropyridine derivative, were performed in comparison with nicardipine. NZ-105 and nicardipine (5, 10 and 20 mg/kg, p.o.) dose-dependently decreased systolic blood pressure in three types of experimentally hypertensive rats, including spontaneously hypertensive rats, renal hypertensive rats and deoxycorticosterone acetate-salt hypertensive rats and normotensive Wistar-strain rats. The hypotensive effects were larger in hypertensive rats than in normotensive Wistar rats. The hypotensive actions of NZ-105 were very slow in onset and long-lasting in all models, e.g., the hypotension by NZ-105 (10 mg/kg, p.o.) reached a peak (-52 mmHg) at 3 hr and lasted for more than 9 hr in spontaneously hypertensive rats. The hypotensive action in spontaneously hypertensive rats was reproducible after repeated dosing twice a day for 29 days. The hypotensive action after i.v. injection of NZ-105 (0.1 mg/kg) in spontaneously hypertensive rats was also slow in onset (peak time: 10 min) and long-lasting (more than 120 min). The hypotensive potency of NZ-105 was about the same as that of nicardipine, but the increment in heart rate was smaller than in the case of nicardipine. Both NZ-105 and nicardipine showed diuretic and natriuretic actions in spontaneously hypertensive rats. After repeated administration, these actions of NZ-105 were unchanged, whereas those of nicardipine were reduced. These results suggest that NZ-105 is a useful antihypertensive drug with concomitant diuretic effects.

Animals↗
PubMedDate not supplied

Effect of OP-2507, a stable prostacyclin analogue on cerebral ischemia induced by unilateral ligation of common carotid artery in gerbils.

Effects of OP-2507 [15-cis-(4-propylcyclohexyl)-16,17,18,19,20-pentanor-9-deoxy -9 alpha-nitrilo- PGF1 methylester] on cerebral ischemia induced by unilateral ligation of common carotid artery in gerbils were investigated with reference to behavioral and neuropathological changes. A good coincidence between neurological symptoms and neuropathological changes was observed in gerbils after unilateral ligation of common carotid artery as revealed by the high percentage of coincidence (90% of total animals). All gerbils which showed neurological symptoms, either circling behavior or rolling fit, had cerebral infarction in their ipsilateral hemisphere. In these animals, neuropathological changes of cerebral regions were observed in cortex, corpus callosum, hippocampus, basal ganglia, interbrain and midbrain, in contrast with medulla oblongata and cerebellum which did not show any neuropathological changes. Pretreatment with a dose range of 1-30 micrograms/kg, s.c. of OP-2507 showed a protective effect in the occurrence of neurological symptoms, such as circling behavior and rolling fit, in a dose-dependent manner. The effect of OP-2507 was also confirmed in neuropathological examination which was performed with observation of neurological deficits in the same animals. The severity of cerebral infarction of all brain regions was significantly prevented by treatment with OP-2507. The results suggested that the protective effect of OP-2507 on regional infarction gave apparent protection against the occurrence of neurological deficits for this compound.

Animals↗
PubMedDate not supplied

Coexistence of aspergillosis and squamous-cell carcinoma in the maxillary sinus proven by preoperative cytology.

The case of a 56-year-old female with coexisting aspergillosis and squamous-cell carcinoma in the maxillary sinus is reported. The diagnosis was established by cytologic study of washings of the sinus before and after admission and was confirmed by exploratory antrotomy. To our knowledge, this is the first case in which the coexistence of fungus and neoplasm in the paranasal sinus was established by preoperative cytologic diagnosis.

Aspergillosis↗
PubMedDate not supplied

[Diagnosis of coronary artery dehiscence and pseudoaneurysm after modified Bentall operation by Doppler color flow imaging: a case report].

This 48-year-old man presented with anterior chest and back pain in 1981. He was treated with replacement of the ascending aorta and aortic valve under a diagnosis of dissection of the ascending aorta with severe aortic regurgitation. He underwent modified Bentall reoperation for the dilation of the aortic root in 1991. Postoperative two-dimensional echocardiography was performed because of sustained atrial flutter. An echo-free space was detected between the aorta graft and aorta wrapping on the short-axis view. Doppler color flow imaging revealed blood flow from the left coronary artery graft into the echo-free space. This leakage was suspected to be the cause of the echo-free space. Transesophageal echocardiography was performed to conform this hypothesis, which revealed blood flow from the left coronary artery graft into the echo-free space in systole and flow into the left coronary artery graft from the echo-free space in diastole.

Anastomosis, Surgical↗
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Studies on the effects of endothelin-1 (ET-1) and endothelin-3 (ET-3) in brain hypoxia and on the participation of brain prostanoids in their actions.

The effects of endothelin-1 (ET-1) and endothelin-3 (ET-3) in brain hypoxia have been studied in mice using the following experimental models: hypobaric hypoxia induced by low atmospheric pressure, histotoxic hypoxia induced by 12.5 mg/kg KCN i.p., and complete ischemia induced by decapitation. ET-1 and ET-3 were injected intracerebroventricularly (i.c.v.) 15 min before the tests. Forebrain tissue concentrations of 6-keto-PGF1 alpha and thromboxane B2 (TxB2) were measured 15 min following i.c.v. administration of ET-1 (5 pmol/mouse) and ET-3 (10 pmol/mouse). ET-1 (1-5 pmol/mouse) and ET-3 (5-25 pmol/mouse) showed a dose-dependent increase in the survival/gasping time in all models of hypoxia. The effect reached its maximum between 15 and 30 min after ET administration and lasted for about 120 min. ET-1 and ET-3 did not significantly change the brain levels of 6-keto-PGF1 alpha and TxB2. The protective effect of ET-1 and ET-3 was unexpected, because endothelins (ETs) are the most potent vasoconstrictors known, and in doses close to those used in this study they cause vasoconstriction and decrease in cerebral blood flow. The protection was not likely to be due either to stimulation of the endogenous release of prostacyclin (PGI2) or to a decrease in the deleterious prostanoid thromboxane A2 (TxA2). Additional experiments are necessary to explain the cerebroprotective effects of ET-1 and ET-3.

Animals↗
PubMedDate not supplied

Evaluation of a new lipophilic prodrug 3', 5'-dioctanoyl-5-bromodeoxyuridine (BrdU-C8) suspended in Lipiodol as a radiosensitizer for the treatment of AH136B tumor.

The effect of anti-cancer treatment on the AH136B tumor was studied using external beam irradiation in combination with a new oil-soluble agent, 3', 5'-dioctanoyl-5-bromodeoxyuridine (BrdU-C8), a lipophilic prodrug of BrdU. BrdU-C8 was dissolved in an oily lymphographic agent, Lipiodol (BrdU-C8/Lipiodol). BrdU-C8/Lipiodol is selectively accumulated in the neovasculature of the tumor and gradually releases BrdU. The AH136B tumor cell, a transplantable rat ascites hepatoma cell line, was implanted in the dorsal foot of rats. In vivo labeling index (L.I.) of the tumor cells after the intraarterial infusion of BrdU-C8/Lipiodol was significantly increased compared to the L.I. observed after intraarterial or intravenous infusion of BrdU. In addition, X-ray irradiation in combination with intraarterial infusion of BrdU-C8/Lipiodol significantly inhibited the tumor growth, indicating the increased radiosensitizing effect.

Animals↗
PubMedDate not supplied

Preoperative diagnosis of Meckel's diverticulum in a 62-year-old man: utility of an angiographic technique.

A 62-year-old man with severe anal bleeding was admitted to our ward as an emergency patient. Angiography of the superior mesenteric artery revealed an omphalomesenteric artery. Methylene blue was injected superselectively into the artery through an angiographic catheter at the time of subsequent laparotomy. Blood supply through the artery to the restricted area of the diverticulum could thus be defined in situ.

Angiography, Digital Subtraction↗
PubMedDate not supplied

Induction of apoptosis in various tumor cell lines by geranylgeraniol.

We have found that GGO is a potent inducer of apoptosis in various human tumor cell lines, including a myeloid multipotential leukemia K562 cell line which is resistant to the induction of apoptosis by various apoptosis-inducing agents and conditions. Polyprenylalcohols with isoprenyl units shorter than the geranylgeranyl group or longer than farnesyl group were less effective in inducing apoptosis in myeloid leukemia HL-60 cells and polyprenylketones had no apoptosis-inducing activity. The fragmentation of DNA in HL-60 cells by GGO was so rapid, no significant effect on the cell cycle was observed. [3H]GGO was taken up by HL-60 cells in 3 h and was incorporated into several proteins. The expression of c-myc and bcl-2 decreased significantly within 3 h of the start of the treatment of HL-60 cells with 50 microM GGO.

Apoptosis↗