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Biomedical subjects

Y Sugimoto

Publications and source records attributed to Y Sugimoto.

At least 127 records · Page 7Linked to original sources
PubMed2000

Effect of mometasone furoate by topical application on allergic rhinitis model in rats.

The effects of mometasone furoate on experimental allergic rhinitis in rats were studied in comparison with that of fluticasone propionate. Topical application of both drugs inhibited dose-dependently the increase of nasal symptoms (sneezing and nasal rubbing) after antigen challenge to the nasal cavity of actively sensitized rats. Mometasone furoate and fluticasone propionate at concentrations of 0.01 or 0.1% significantly inhibited both nasal rubbing and sneezing 1 h after topical application of both drugs. The relative potencies of mometasone furoate in nasal rubbing and sneezing compared to fluticasone propionate were 5.01 and 6.87, respectively. Mometasone furoate (0.02%) and fluticasone propionate (0.1%) significantly inhibited the increase of antigen-induced nasal rubbing even 6 h after topical application, indicating that both drugs have a long-lasting effect.

Administration, Topical↗
PubMed2000

Uterine expression of prostaglandin H2 synthase in late pregnancy and during parturition in prostaglandin F receptor-deficient mice.

PG production in uterine tissues is important for many physiological processes in late pregnancy, including parturition. We examined the expression of the PGH2 synthases, cyclooxygenase-1 (COX-1) and COX-2, in uterine tissues during late pregnancy, using PGF receptor-deficient (FP-/-) mice. Female FP-/- mice are unable to deliver normal fetuses at term, as they do not undergo luteolysis necessary for parturition. In wild-type mice, COX-1 messenger RNA (mRNA) was expressed in the endometrial epithelium, myometrium, and decidua throughout late pregnancy. The expression of COX-1 mRNA in the endometrial epithelium and myometrium decreased both in wild-type mice undergoing natural parturition and in FP-/- mice undergoing ovariectomy-induced parturition, but expression of COX-1 mRNA was enhanced in FP-/- mice at the expected term. In wild-type mice, COX-2 mRNA was not expressed in the myometrium before parturition, but was markedly induced during parturition. This induction of COX-2 was absent in FP-/- mice at the expected term, but was found during ovariectomy-induced parturition in these mice. Expression of COX-2 proteins was confirmed by immunohistochemical analysis. Thus, in uterine tissues, myometrial expression of COX-2 is closely associated with the occurrence of parturition, but uterine expression of COX-1 is induced much earlier and kept at a high level until parturition occurs. These results suggest that COX-1-derived PGs are responsible for the induction of luteolysis, and that COX-2-derived PGs play a role in the final pathway of parturition.

Animals↗
PubMed2000

The role of prostaglandin E receptor subtypes (EP1, EP2, EP3, and EP4) in bone resorption: an analysis using specific agonists for the respective EPs.

PGE2 functions as a potent stimulator of bone resorption. The action of PGE2 is thought to be mediated by some PGE receptor subtypes present in osteoblastic cells. In this study, we examined the involvement of PGE receptor subtypes, EP1, EP2, EP3, and EP4, in PGE2-induced bone resorption using specific agonists for the respective EPs. In mouse calvaria cultures, EP4 agonist markedly stimulated bone resorption, but its maximal stimulation was less than that induced by PGE2. EP2 agonist also stimulated bone resorption, but only slightly. EP1 and EP3 agonists did not stimulate it at all. RT-PCR showed that osteoblastic cells isolated from newborn mouse calvaria expressed all of the EPs messenger RNA (mRNA). Both EP2 agonist and EP4 agonist induced cAMP production and the expression of osteoclast differentiation factor (ODF) mRNA in osteoblastic cells. Simultaneous addition of EP2 and EP4 agonists cooperatively induced cAMP production and ODF mRNA expression. In mouse bone marrow cultures, EP2 and EP4 agonists moderately induced osteoclast formation, but the simultaneous addition of the two agonists cooperatively induced it, similar to that by PGE2. In calvaria culture from EP4 knockout mice, a marked reduction in bone resorption to PGE2 was found. In EP4 knockout mice, EP4 agonist failed to induce bone resorption, but EP2 agonist slightly, but significantly, induced bone resorption. These findings suggest that PGE2 stimulates bone resorption by a mechanism involving cAMP and ODF, which is mediated mainly by EP4 and partially by EP2.

Animals↗
PubMed2000

Effects of fujibitol, a remedy for nasal symptoms, on experimental allergic rhinitis in rats.

The effects of Fujibitol, a preparation of crude drugs in wide clinical use for treatment of chronic rhinitis and empyema, on experimental allergic rhinitis in rats were studied. Fujibitol inhibited nasal allergic symptoms, i.e. sneezing and nasal rubbing, induced by antigen in sensitized animals. An increase in dye leakage into the nasal cavity induced by antigen was also inhibited by Fujibitol. On the other hand, no inhibitory effects were observed on either the nasal allergic symptoms or increase in dye leakage into the nasal cavity induced by histamine. However, Fujibitol was effective in inhibiting histamine release from the nasal cavity induced by antigen. Oxatomide used as positive control drug showed potent inhibitory effects on nasal symptoms and dye leakage into the nasal cavity induced by histamine and antigen. These results suggested that Fujibitol showed a remarkable protective effect against experimental rhinitis induced by antigen via inhibition of histamine release from the nasal cavity.

Animals↗
PubMed2000

Effects of a nitric oxide synthase inhibitor on hypophagia induced by the peripheral 5-HT receptor agonists, alpha-methyl-5-hydroxytryptamine and 5-carboxamidotryptamine in rats.

We investigated the effects of the nitric oxide (NO) synthase inhibitor, N(G)-nitro-L-arginine methyl ester (L-NAME) on hypophagia in rats elicited by alpha-methyl-5-hydroxytryptamine (alpha-methyl-5-HT) and 5-carboxamidotryptamine (5-CT) which are suggested to be mediated by the peripheral 5-HT2A and 5-HT7 receptor, respectively. Both alpha-methyl-5-HT and 5-CT apparently inhibited food intake in food-deprived rats. L-NAME significantly enhanced alpha-methyl-5-HT-elicited hypophagia, while it inhibited 5-CT-elicited hypophagia. These results suggest that NO is differentially related to alpha-methyl-5-HT and 5-CT-induced hypophagia and that NO may play a role in hypo- and hyperphagia.

Animals↗
PubMed2000

Effects of the 5-HT2A receptor agonist 1-(2,5-dimethoxy-4-iodophenyl)-2-aminopropane (DOI) on plasma glucose and glucagon levels of rats.

Effects of the 5-hydroxytryptamine (5-HT)2A receptor agonist 1-(2,5-dimethoxy-4-iodophenyl)-2-aminopropane (DOI) on plasma glucagon levels were studied in rats. Systemic injection of DOI induces significant increases in plasma glucagon levels. Hyperglucagonemia induced by DOI was dose-dependently prevented by the 5-HT2A receptor antagonist ketanserin. Adrenodemedullation abolished hyperglucagonemia elicited by DOI. Previous report demonstrated that the peripheral 5-HT2A receptor agonist induces hyperglycemia in rats but does not increase plasma glucagon levels at doses inducing hyperglycemia. Therefore, our findings suggest that DOI-induced glucagon release was elicited by stimulation of the central 5-HT2A receptor, which in turn increasing adrenaline release.

Adrenal Medulla↗
PubMed2000

Experimental allergic conjunctivitis in guinea pigs induced by Japanese cedar pollen.

We report a new experimental allergic conjunctivitis with Japanese cedar pollen as antigen in guinea pigs, and the immunological characteristics of this model were also elucidated. Allergic conjunctivitis was developed by immunization in guinea pigs with a mixture containing Japanese cedar pollen and killed Bordetella pertussis. When local application of Japanese cedar pollen suspension 14 d after systemic immunization was performed every 3d, remarkable conjunctivitis was observed from 20 to 35 d. Increase in vascular permeability and decrease in histamine contents of the conjunctiva were also observed after local application of antigen. Passive cutaneous anaphylactic (PCA) reactions revealed that both IgG- and IgE-rich antibodies were produced in this model. Chlorpheniramine, ketotifen and levocabastine were effective in inhibiting cedar pollen-induced conjunctivitis. Although a high concentration was needed, tranilast and amlexanox also showed significant inhibition of conjunctivitis induced by cedar pollen.

Animals↗
PubMed2000

[Physiological functions of prostanoid receptors and their subtypes].

Prostaglandins exert a wide variety of biological actions through specific receptors. The prostaglandins PGE2 and PGF2 alpha have been suggested to affect many physiological processes. There have been four pharmacologically identified receptor subtypes, EP1 through EP4 for PGE2 and a single receptor type, FP for PGF2 alpha. However, it is yet unknown as to which receptor is involved in each process. To make this clear, we investigated the distribution of these receptors in various systems and established mice deficient in each receptor and examined their physiology. Finally, we found that these receptors are involved in several processes associated with reproduction physiology. FP-deficient mice are able to become pregnant, but cannot deliver their pups because of the lack of parturition; luteolysis does not occur normally. EP2-deficient mice are able to become pregnant, but their litter sizes are much reduced, which is due to defects in ovulation and fertilization; cumulus cell function is impaired. EP4-deficient mice die within a few days after birth because of patency of the ductus arteriosus; remodeling of cardiovascular system during birth is impaired. Thus, the E- and F-types of prostaglandins play roles in cumulus function, luteolysis and ductus closure through EP2, FP and EP4, respectively.

Animals↗
PubMed2000

Participation of GABAergic and histaminergic systems in inhibiting amygdaloid kindled seizures.

The effects of GABAmimetic drugs on inhibition of amygdaloid kindled seizures induced by clobenpropit were investigated to clarify the relationship between histaminergic and GABAergic systems in seizures. I.p. injection of clobenpropit caused dose-dependent inhibition of amygdaloid kindled seizures. GABAmimetic drugs such as diazepam, sodium valproate and muscimol also inhibited amygdaloid kindled seizures in a dose-dependent manner. Diazepam at doses of 0.2 and 0.5 mg/kg, which showed no significant effect on amygdaloid kindled seizures when used separately, significantly potentiated the effect of clobenpropit. Similar findings were observed with sodium valproate and muscimol at doses of 100 mg/kg and 5 ng, respectively, although neither showed any significant effects when administered separately. Bicuculline caused significant antagonism of the inhibition of amygdaloid kindled seizures induced by clobenpropit, while the effect of diazepam was not antagonized by diphenhydramine. These results suggested that inhibition of amygdaloid kindled seizures induced by histamine is closely associated with the actions of GABA.

Amygdala↗
PubMed2000

Roles of prostanoids revealed from studies using mice lacking specific prostanoid receptors.

The actions of prostanoids in various physiological and pathophysiological conditions have been being examined using mice lacking different prostanoid receptors. Prostaglandin (PG) I2 worked not only as a mediator of inflammation but also as an antithrombotic agent. PGF2alpha was found to be an essential inducer of labor. Several important actions of PGE2 are exerted via each of the four PGE2 receptor subtypes: EP1, EP2, EP3 and EP4. PGE2 participated in colon carcinogenesis via the EP1. PGE2 also participates in ovulation and fertilization and contributes to the control of blood pressure under high-salt intake via the EP2. PGE2 worked as a mediator of febrile responses to both endogenous and exogenous pyrogens and as a regulator of bicarbonate secretion induced by acid-stimulation in the duodenum via the EP3. It regulated the closure of ductus arteriosus and showed bone resorbing action via the EP4. PGD2 was found to be a mediator of allergic asthma. These studies have revealed important roles of prostanoids, some of which had not previously been known.

Animals↗
PubMed2000

Influences of everninomicin, vancomycin and teicoplanin on chemical mediator release from rat peritoneal mast cells.

We examined influences of certain antibiotics on the release of chemical mediators from isolated rat peritoneal mast cells in vitro. Isolated peritoneal mast cells were obtained from male Wistar strain rats. Everninomicin (0.06-1.2 mg/ml), vancomycin (0.05-1.0 mg/ml), teicoplanin (0.07-1.4 mg/ml) and concanavalin A (0.01 mg/ml) were used. Isolated mast cells were incubated in the presence of various concentrations of the test compound at 37 degrees C for 10 min. Histamine contents of the supernatant and cell pellet were measured by an automated fluorometric method. Prostaglandin D2 (PGD2) contents of the supernatant were determined by enzyme immunoassay. Everninomicin (0.06-1.2 mg/ml) had no influence on histamine and PGD2 release from mast cells. On the other hand, vancomycin significantly released both histamine (0.5 and 1.0 mg/ml) and PGD2 (1.0 mg/ml) from mast cells, but vancomycin did not affect concanavalin A-induced histamine and PGD2 release. Teicoplanin (more than 0.07 mg/ml) significantly stimulated histamine and PGD2 release from mast cells and it also significantly potentiated concanavalin A-induced histamine and PGD2 release. These results suggest that everninomicin causes no chemical mediator release from mast cells, different from vancomycin and teicoplanin.

Aminoglycosides↗
PubMed2000

Crucial involvement of the EP4 subtype of prostaglandin E receptor in osteoclast formation by proinflammatory cytokines and lipopolysaccharide.

Prostaglandin E2 (PGE2) exerts its effects through the PGE receptor that consists of four subtypes (EP1, EP2, EP3, and EP4). Osteoclast formation in the coculture of primary osteoblastic cells (POB) and bone marrow cells was enhanced more by 11-deoxy-PGE1 (an EP4 and EP2 agonist) than by butaprost (an EP2 agonist) and other agonists, which suggests that EP4 is the main factor in PGE2-induced osteoclast formation. PGE2-induced osteoclast formation was not observed in the coculture of POB from EP4-deficient (EP4 k/o) mice and spleen cells from wild-type (w/t) mice, whereas osteoclasts were formed in the coculture of POB from w/t mice and spleen cells from EP4-k/o mice. In situ hybridization (ISH) showed that EP4 messenger RNA (mRNA) was expressed on osteoblastic cells but not on multinucleated cells (MNCs) in w/t mice. These results indicate that PGE2 enhances osteoclast formation through its EP4 subtype on osteoblasts. Osteoclast formation by interleukin 1alpha (IL-1alpha), tumor necrosis factor alpha (TNF-alpha), basic fibroblast growth factor (bFGF), and lipopolysaccharide (LPS) was hardly observed in the coculture of POB and bone marrow cells, both from EP4-k/o mice, which shows the crucial involvement of PG and the EP4 subtype in osteoclast formation by these molecules. In contrast, osteoclast formation by 1,25-hydroxyvitamin D3 (1,25(OH)2D3) was not impaired and that by parathyroid hormone (PTH) was only partially impaired in EP4-k/o mice, which may be related to the fact that EP4-k/o mice revealed no gross skeletal abnormalities. Because it has been suggested that IL-1alpha, TNF-alpha, bFGF, and LPS are involved in inflammatory bone loss, our work can be expected to contribute to an understanding of the pathophysiology of these conditions.

Animals↗
PubMed2000

New Cdc25B tyrosine phosphatase inhibitors, nocardiones A and B, produced by Nocardia sp. TP-A0248: taxonomy, fermentation, isolation, structural elucidation and biological properties.

Strain TP-A0248 which produces two new Cdc25B tyrosine phosphatase inhibitors and also possessing antifungal activity, designated nocardiones A (1) and B (2), was considered to belong to the genus Nocardia on the basis of literature comparison of chemotaxonomic properties. The nocardiones were isolated by solvent extraction of fermentation broth of Nocardia sp. TP-A0248 and purified by the conventional column chromatography. Spectroscopic studies led to determination that 1 and 2 belong to a class compound of naphtho[1,2-b]furan-4,5-diones. Compound 1 inhibited the activity of Cdc25B, PTP1B and FAP-1 protein tyrosine phosphatases at a concentration of 10 microM. It also showed moderate in vitro antifungal and cytotoxic activity.

Antifungal Agents↗
PubMed2000

[Neoadjuvant chemotherapy for esophageal cancer by administration of nedaplatin alone].

The possibility of safe implementation of neoadjuvant chemotherapy using nedaplatin (254-S) was investigated with the aim of improving the therapeutic results in advanced esophageal cancer patients. The subjects had usually undergone two courses of 254-S, 80 or 100 mg/m2, preoperatively, at intervals of 4 weeks. After chemotherapy, responses were evaluated, and resection was undertaken 4 weeks after the final administration. The subjects were 10 patients with untreated esophageal cancer. As a result of evaluation of responses of main lesions to chemotherapy, a partial response (PR) was observed in 3 patients, and a minor response 3, showing an efficacy rate of 30%. Pathological findings before treatment were determined by staining of a cell cycle marker (Ki-67). The 3 patients who were evaluated as PR (clinical efficacy) showed high rates of positivity for Ki-67 of 47.4%, 52.7%, and 86%, respectively. There were no serious complications and no death related to operation. The observations suggested that 254-S, which has little or no side effects including nephrotoxicity, can become the standard remedy for esophageal cancer instead of CDDP in future.

Aged↗
PubMed2000

[Immunohistochemical study of apoptosis of lens epithelial cells in human and diabetic rat cataracts].

PURPOSE: To evaluate apoptosis of lens epithelial cells with immunohistochemical methods. METHODS: We performed terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labeling (TUNEL) assays on capsulotomy specimens (68 eyes in 53 patients) from patients who had undergone cataract surgery and an epithelium of diabetic cataracts in rats (144 eyes in 72 rats). The animal model of diabetic cataracts was prepared by injection of streptozotocin in three-week old rats. The rats were also examined using the proliferating cell nuclear antigen (PCNA) immunohistochemical staining method. RESULTS: Although some TUNEL-positive cells were detected in capsulotomy specimens, we recognized little correlation between its distribution and morphological classification of cataracts. In the animal model of diabetic cataracts, TUNEL-positive cells were seen around the region where epithelial cells had accumulated. In the accumulated region, PCNA labeled cells undergoing DNA synthesis were also detected. CONCLUSION: These results suggest the possibility that apoptosis occurs in human lens epithelial cells and apoptosis and proliferation may be induced by factors such as hyperglycemia.

Aged↗
PubMed2000

The mechanism responsible for the drowsiness caused by first generation H1 antagonists on the EEG pattern.

The present study was performed to clarify the mechanism responsible for the drowsiness caused by first generation H1 antagonists according to electroencephalogram activity. All H1 antagonists used in the present study caused the EEG-recorded drowsiness pattern, i.e., increases in EEG power spectra of the delta and theta bands at the frontal cortex in rats. The potency of cyproheptadine was greater than those of diphenhydramine and promethazine, while that of pyrilamine was less than those of the other drugs examined. The increase in EEG power spectra in the delta band induced by H1 antagonists was antagonized by pretreatment with both histidine and physostigmine. The effect of pyrilamine was more potently antagonized by histidine and less potently antagonized by physostigmine as compared to diphenhydramine, promethazine and cyproheptadine. The increases in EEG power spectra induced by H1 antagonists were neither antagonized nor potentiated by 5-hydroxytryptophan. These results clearly indicate that the increases in EEG power spectra in the delta and theta bands at the frontal cortex in rats induced by first generation H1 antagonists are responsible for both histaminergic and cholinergic mechanisms.

5-Hydroxytryptophan↗