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Biomedical subjects

Y Nomura

Publications and source records attributed to Y Nomura.

At least 19 recordsLinked to original sources
PubMed1992

Randomized adjuvant trial to evaluate the addition of tamoxifen and PSK to chemotherapy in patients with primary breast cancer. 5-Year results from the Nishi-Nippon Group of the Adjuvant Chemoendocrine Therapy for Breast Cancer Organization.

BACKGROUND: A randomized adjuvant trial was conducted from October 1982 to January 1985 to evaluate the addition of tamoxifen (TAM) to combination chemotherapy with perioperative mitomycin C (MMC) and ftorafur (FT) for patients with estrogen receptor (ER)-positive tumors and the addition of PSK, a biologic response modifier, to MMC+FT chemotherapy for patients with ER-negative tumors in operable Stage IIA, IIB, and IIIA cancer. The doses used were 20 mg of oral TAM daily, 600 mg of oral FT daily, and 3 g of oral PSK daily for 2 years. Intravenous MMC (13 mg/m2) was given on the day of operation. METHODS: A total of 967 patients were entered and randomized by stratification based on ER status and staging (1978 International Union Against Cancer [UICC] criteria at the time of trial execution). Of 967 patients, 914 (94.5%) were evaluable. At 5-year follow-up, significant prolonged overall survival (OS) and relapse-free survival (RFS) times were seen with the addition of TAM in patients with ER-positive and Stage IIIA T3N0 cancer (1987 UICC-American Joint Committee on Cancer [AJCC] criteria); however, no significant survival benefit from TAM was seen in patients with ER-positive and Stage IIA T2N1 cancer. There was no significant difference between regimens, with or without PSK, in patients with ER-negative disease. RESULTS: Results of subset analyses suggested a benefit from TAM in postmenopausal patients with ER-positive and Stage IIA T2N1 cancer and a benefit from PSK in patients with node-negative, ER-negative, and Stage IIA T2N1 cancer. CONCLUSIONS: The 5-year results of the current trial showed a survival advantage by the addition of TAM to chemotherapy in patients with ER-positive and Stage IIIA T3N0 cancer.

Adjuvants, Immunologic↗
PubMed1992

Nucleosides and nucleotides. 112. 2-(1-Hexyn-1-yl)adenosine-5'-uronamides: a new entry of selective A2 adenosine receptor agonists with potent antihypertensive activity.

Chemical modifications of the potent A2 adenosine receptor agonist 2-(1-hexyn-1-yl)adenosine (7, 2-HA) at the 5'-position have been carried out to find more potent and selective A2 agonists. These analogues were evaluated for adenosine A1 and A2 receptor binding affinity in rat brain tissues and antihypertensive effects in spontaneously hypertensive rats (SHR). Among the series of compounds, 2-(1-hexyn-1-yl)adenosine-5'-N-cyclopropyluronamide (16d) had the most potent affinity to the A2 receptor with a Ki of 2.6 nM, which is essentially the same as that of the parent agonist, 2-HA. However, the most selective agonist for the A2 receptor was 2-(1-hexyn-1-yl)adenosine-5'-N-methyluronamide (16b) with a Ki of 11 nM and a 162-fold selectivity. The N-alkyl substituents of 5'-uronamide derivatives did not seem to potentiate the A2 binding affinity but drastically reduced the A1 affinity compared with the parent 2-HA. Therefore, the A1/A2 selectivity was consequently increased. Other 5'-deoxy-5'-substituted derivatives of 2-HA such as the chloro (20), carboxamide (27, 28), sulfonamide (29), urea (30), and thiourea (22) analogues were also prepared. Among these nucleosides, no active compounds with potent or selective affinities to both receptors were found except 20. Although glycosyl conformations and sugar-puckering of these nucleosides were studied by 1H NMR spectroscopy, there were no positive correlations between active and inactive agonists. 2-(1-Hexyn-1-yl)adenosine-5'-uronamide (16a) and 16d had a potent hypotensive effect at ED30 values of 0.18 and 0.17 micrograms/kg, respectively, upon iv administration to anesthetized SHR.

Adenosine↗
PubMed1992

Selective potentiation of N-methyl-D-aspartate-induced current by protein kinase C in Xenopus oocytes injected with rat brain RNA.

Glutamate receptors and protein kinase C (PKC) may play significant roles in long-term potentiation in hippocampus. To clarify the regulatory involvement of PKC in the functions of glutamate receptors, we examined the effects of PKC activation on current response induced by the activation of each subtype of glutamate receptor in Xenopus oocytes injected with rat brain RNA. Treatment with the PKC activator, 12-O-tetradecanoylphorbol-13-acetate (TPA), potentiated N-methyl-D-aspartate (NMDA)-induced current by about 2.5-fold, although it did not affect kainate-induced current at all. Quisqualate-mediated oscillatory current was almost abolished by this treatment. The TPA-induced potentiation of NMDA current was suppressed by staurosporine, an inhibitor of protein kinases. Pretreatment with 4-O-methyl-TPA, an inactive phorbol ester, had no effect on NMDA current. Current response mediated by NMDA receptors would thus appear to be modulated by PKC.

Animals↗
PubMed1992

Age-related changes in transmitter glutamate and NMDA receptor/channels in the brain of senescence-accelerated mouse.

The senescence-accelerated mouse (SAM-P/8) is known as a murine model of aging and memory dysfunction. In the hippocampus and cerebral cortex of P/8, the contents of glutamic acid and glutamine were significantly higher than those of normal strain R/1 during 2 and 14 months. High K(+)-evoked endogenous glutamic acid release from the slices of P/8 was increased in comparison with R/1 at 9 and 11 months. In addition, the Bmax of [3H]dizocilpine (MK-801, channel blocker for N-methyl-D-aspartic acid receptor/channel) binding in the cerebral cortex was age-dependently decreased in P/8 but not in R/1. These results suggest that synaptic dysfunctions in the glutamatergic system occur in the CNS of SAM-P/8.

Aging↗
PubMed1992

Relative effect of steroid hormone receptors on the prognosis of patients with operable breast cancer. A univariate and multivariate analysis of 3089 Japanese patients with breast cancer from the Study Group for the Japanese Breast Cancer Society on Hormone Receptors and Prognosis in Breast Cancer.

In a retrospective multicenter study to investigate the correlation between estrogen (ER) and/or progesterone receptors (PgR) in primary breast cancer with patient prognosis, 3118 patients with operable breast cancer (International Union Against Cancer Stages I, II, and III) were investigated from ten hospitals in Japan who underwent surgery from October 1972 to December 1982; 3089 were evaluable. The ER-positive and PgR-positive cancers were found in 56% and 34% of patients, respectively. The positivities decreased as the tumor size increased but were independent on lymph node metastasis. There were no significant differences in relapse-free survival (RFS) in relation to receptor status (median follow-up, 89 months [ER], 84 months [PgR]). However, in patients with four or more positive nodes, those with PgR-positive cancer had a longer RFS. The patients with ER-positive cancer survived significantly longer than ER-negative ones, with the greatest difference seen in those with four or more positive nodes. There was a significantly longer postrelapse survival (PRS) for patients with ER-positive cancer because of the different distribution of the major metastasis and better responses to first-line and subsequent treatments. Cox's multivariate analysis showed that overall survival but not PRS was affected by ER (and more weakly by PgR) because of the longer PRS in patients with ER-positive cancer.

Adult↗
PubMed1992

Caloric irregularity in experimentally induced perilymphatic fistula.

The term "caloric irregularity" was coined to refer to a gross irregularity in the amplitude and/or frequency of a caloric-induced nystagmus, having a variable slow-phase velocity and prolonged duration. Twelve of 46 guinea pigs with experimentally induced perilymphatic fistula had irregular responses to the ice-water caloric test 1 week after creation of a fistula. The long-term vestibular consequences in animals with caloric irregularities were either resolution and return to normal function (i.e. caloric return) or continuing deterioration to canal paresis. Morphological examination of ears with caloric irregularity revealed that there had been partial collapse of the membranous labyrinth and the creation of a floating labyrinth.

Animals↗
PubMed1992

Age-related changes in NMDA-induced [3H]acetylcholine release from brain slices of senescence-accelerated mouse.

From the brain slices of normal mice (ddY strain, subcloned from dd strain in National Institute of Health in Japan), N-methyl-D-aspartic acid (NMDA) at 0.01-1 mM evoked [3H]acetylcholine (ACh) release in a concentration dependent manner. [3H]ACh release evoked by 1 mM NMDA was significantly inhibited by 2-amino-5-phosphonovaleric acid (APV), phencyclidine (PCP) and 5-methyl-10,11-dihydroxy-5H-dibenzo[a,d]cyclohepten-5,10-imine maleate (MK-801). The effects of NMDA were not seen in the Ca2+ free medium and were inhibited by physiological concentration (0.83 mM) of Mg2+. NMDA seems to cause ACh release from nerve terminals through the receptor-ion channel mediated mechanism in the mouse brain. Based upon these results, we determined the activity of a high K(+)- or NMDA-evoked [3H]ACh release using prone/8 strain of senescence-accelerated mouse (SAM-P/8) (a murine model of accelerated aging and memory dysfunction) and SAM-resistance/1 strain (SAM-R/1) (normal aging mice as the control) and these release activities were compared between both strains and during aging. [3H]ACh release evoked by 30 mM KCl was significantly lower than that of age-matched SAM-R/1 at 9 and 12 months. NMDA evoked the [3H]ACh release at 2, 6, 10 and 14 months in R/1 mice. In SAM-P/8 mice the activity of NMDA-evoked release was seen at 2 months, but markedly decreased afterwards. Nonsignificant difference was observed on the uptake of [3H]choline and on the spontaneous release of [3H]ACh between SAM-P/8 and SAM-R/1 strains, and during aging.(ABSTRACT TRUNCATED AT 250 WORDS)

Acetylcholine↗
PubMed1992

"Floating" labyrinth. Pathophysiology and treatment of perilymph fistula.

Collapse of the membranous labyrinth of the pars superior is a morphological change observed in 50% of animals with experimentally produced perilymph fistula, although the extent and degree of the collapse may vary greatly. The moderately collapsed membranous labyrinth may drift with CSF and/or perilymph pressure changes and this may stimulate sensory cells of the utricle and/or semicircular canals if the sensory cells are intact and the collapsed wall is in contact with the otolithic membrane and/or cupula. This condition is termed "floating" labyrinth. Caloric irregularity is often observed in electronystagmograms recorded from animals with experimental perilymph fistula. This is also observed in patients with perilymph fistula. Partial destruction of the vestibular organs using argon laser was performed in a patient with perilymph fistula who was incapacitated because of persistent positional vertigo after closure of the oval window fistula. Irradiation of the argon laser beam was directed to the macula utriculi, utriculoampullary nerve and singular nerve. The hearing of the patient was maintained, and vertigo disappeared after laser labyrinthectomy.

Audiometry, Pure-Tone↗
PubMed1992

Diet and prognosis of breast cancer.

The relationship between the occurrence of breast cancer and dietary intake, in particular a high-fat diet, has attracted much attention in recent years. In addition, the prognosis of breast cancer patients on the basis of dietary intake is also an interesting subject. The present study utilized breast cancer patients whose dietary intake was carefully assessed about one decade previously in a case-control study to determine whether dietary intake was indeed related to the patients' prognosis. The study included 212 patients who underwent a surgical operation between 1975 and 1978. They were followed-up until 1987, and a total of 47 breast cancer deaths were certified. The 5- and 10-year relative survival rates were 78.5% and 75.3%, respectively. The older patients tended to ingest smaller amounts of all nutrients, except animal fat from fish. Height was significantly correlated with total animal protein intake, whereas there was no significant correlation between body mass index and intake of any nutrient. Although the age-adjusted mean values of the nutrient intakes, other than vegetable fat, decreased with advancing stage, the differences were statistically insignificant. The results of multivariate analyses, in which some confounding factors (e.g., clinical stage) were adjusted using a proportional hazards model, showed that all hazards ratios in each nutrient were close to unity, and no dose-response relationship was seen. The present investigation did not provide any support for the hypothesis that a high-fat diet is a survival determinant for breast cancer patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Breast Neoplasms↗
PubMed1992

Characterization of inorganic fillers in visible-light-cured dental composite resins.

Inorganic fillers in seven visible-light (VL)-cured dental composite resins were examined for their size, composition, phase and content, employing the following analytical instruments. SEM observations indicated that five samples could be classified into the hybrid type while the remaining two belonged to micro-filled and sub-micron types. EDX analyses revealed that five samples contained BaO while others lacked BaO. XRD analyses showed that three were in vitreous phase, two were in the crystalline phase and two were mixtures of both. DTG thermal analyses indicated that the hybrid type composites had the higher inorganic filler content (wt%) than the composites of two other types. In conclusion, wide varieties exist in the inorganic fillers in VL-cured dental composite resins currently utilized.

Aluminum Oxide↗
PubMed1992

Glutamate inhibits adenylate cyclase activity in dispersed rat hippocampal cells directly via an N-methyl-D-aspartate-like metabotropic receptor.

Three major subtypes of glutamate receptors that are coupled to cation channels--N-methyl-D-aspartate (NMDA), kainate, and alpha-amino-3-hydroxy-5-methylisoxazole-4-propionate (AMPA) receptors--are known as ionotropic receptors in the mammalian CNS. Recently, an additional subtype that is coupled to GTP binding proteins and stimulates (or inhibits) metabolism of phosphoinositides has been proposed as a metabotropic receptor. Incubation of dispersed hippocampal cells from adult rats with glutamate or NMDA decreased forskolin-stimulated cyclic AMP (cAMP) accumulation; half-maximal effects were obtained with 5.6 +/- 2.2 and 6.4 +/- 2.3 microM, respectively. Kainate and quisqualate were less potent. The effect of glutamate was antagonized by 2,3-diaminopropionate and 2-amino-5-phosphonovalerate, NMDA/glutamate receptor antagonists, but not by 0.5 microM Joro spider toxin, a specific blocker of the AMPA receptor. The inhibitory effect of glutamate on cAMP formation was not blocked by 2 microM tetrodotoxin or by the absence of Ca2+. In hippocampal membranes, glutamate, similar to carbachol, inhibited adenylate cyclase activity in a GTP-dependent manner. These findings suggest that the glutamate inhibition of adenylate cyclase is direct and is not due to a result of the release of other neurotransmitters. The effect of glutamate on cAMP accumulation was observed in an assay medium containing 0.7 mM MgCl2, which is known to inhibit both ionotropic NMDA receptor/channels in the hippocampus and metabotropic NMDA receptors in the cerebellum. The inhibitory effect of glutamate was abolished by pertussis toxin treatment.(ABSTRACT TRUNCATED AT 250 WORDS)

Adenylyl Cyclase Inhibitors↗
PubMed1992

Involvement of growth-associated protein-43 with irreversible neurite outgrowth by dibutyryl cyclic AMP and phorbol ester in NG108-15 cells.

Simultaneous treatment with 12-O-tetradecanoylphorbol 13-acetate (TPA) and dibutyryl cyclic AMP (diBu-cAMP) for 72 h induced neurites in NG108-15 cells significantly longer than treatment with each alone. Treatment for 72 h with both drugs induced irreversible neurite extension and a decline in protein kinase C activity, although neurites extended by diBu-cAMP alone disappeared after the withdrawal of the drug. The expression of growth-associated protein-43 (GAP-43) mRNA was also observed by a combined application of TPA and diBu-cAMP. The increased level of GAP-43 mRNA induced by treatment with both drugs for 72 h was maintained at least 24 h after withdrawal of the drugs. In cells transfected with GAP-43 cDNA, neurites induced by treatment with diBu-cAMP alone for 72 h were maintained at least 48 h after removal of the drugs. These results suggest that GAP-43 could be involved in the maintenance of elongated neurites and that a decline in protein kinase C activity may be involved in the accumulation of GAP-43.

Animals↗
PubMed1992

Interleukin-8 is a major neutrophil chemotactic factor derived from cultured human gingival fibroblasts stimulated with interleukin-1 beta or tumor necrosis factor alpha.

Inflammatory mediators produced by cells in the gingiva have been implicated in the initiation and progression of periodontal disease, a common infectious disease. In this study, we examined the biological activity of neutrophil chemotactic factors and the kinetics of expression of interleukin-8 (IL-8) mRNA derived from normal gingival fibroblasts in response to inflammatory mediators in an in vitro model. Gingival fibroblasts stimulated by either recombinant human interleukin-1 beta or recombinant human tumor necrosis factor alpha produced neutrophil chemotactic factors after 4 h, whereas expression of cell-derived IL-8 mRNA was detected within 1 h after stimulation. Furthermore, in a neutralization assay, rabbit anti-recombinant human IL-8 antiserum inhibited neutrophil chemotactic activity to basal levels. These results provide evidence that gingival fibroblasts synthesize potent chemotactic factors such as IL-8 in the presence of the inflammatory mediators interleukin-1 beta and tumor necrosis factor alpha. The activity of these factors may contribute to neutrophil-mediated processes in the pathogenesis of periodontal disease.

Cells, Cultured↗
PubMed1992

Vestibular pathophysiologic changes in experimental perilymphatic fistula.

An animal model of experimental perilymphatic fistula (EPLF) was developed in the guinea pig in order to study vestibular pathophysiology. In experimental animals, 4 microL of perilymph was suctioned from one cochlea via the round window membrane. Changes in vestibular function were as follows. 1) During the acute stage (5 hours postoperatively), spontaneous nystagmus directed toward the normal side was noted in 57.4% of the EPLF animals. This lasted less than 24 hours. 2) One week postoperatively, direction-fixed positional nystagmus toward the lesioned ear was present in 22.7% of the EPLF animals, especially when the lesioned ear was positioned inferiorly. 3) With the ice water caloric test, no response was present in 58.1% of the EPLF animals and an irregular response was found in 22.6% of them, 1 week postoperatively. These results tend to indicate that tests of vestibular function may differentiate between patients with Meniere's disease and those with perilymphatic fistula. Histologic findings indicate that a floating labyrinth is the cause of positional nystagmus and caloric irregularity. The absence of caloric responses was associated with collapse of the vestibular labyrinth.

Animals↗