Search PubMed⌕ Search

Biomedical subjects

Y Furuya

Publications and source records attributed to Y Furuya.

At least 181 records · Page 10Linked to original sources
PubMed1991

Determinations of organ doses and effective dose equivalents from computed tomographic examination.

The organ or tissue doses were determined with a phantom measurement for 12 types of CT scanners widely used in Japan. Two types of thermoluminescent dosimeters were used for the dose determinations in a Rando woman phantom. The effective dose equivalents recommended by the International Commission on Radiological Protection were calculated using the measured organ or tissue doses. It was found that the CT scanners currently available give quite different organ or tissue doses. When selecting the optimum technical factors for scanning, therefore, it is important to take into consideration the balance of the image quality and the radiation exposure to patients.

Female↗
PubMed1991

Effects of estrogen on growth of androgen-responsive rat prostatic tumor (R 3327).

It has been known that estrogen has synergistic effects with androgen on growth of normal male accessory sex organs of rats. The present study was therefore undertaken to examine the effects of estrogen on androgen-responsive rat Dunning R 3327 prostatic tumor. The weight of male accessory sex organs was suppressed by estrogen on growth of treatment, but synergistic effects of estrogen and androgen on these organs were seen following combined treatment with androgen and estrogen. In contrast to the effects of estrogen on accessory sex organs, estrogen influenced a R 3327 tumor only in the negative direction regardless of whether androgen was injected simultaneously or not. When the dihydrotestosterone injection was reduced from 500 to 100 micrograms/rat/day after the tumor appeared as subcutaneous nodules, the weight of the accessory sex organs was similar to that of the control animals. However, this amount of dihydrotestosterone increased tumor growth equally when compared to those treated with a pharmacological dose of dihydrotestosterone. Therefore, the response of R 3327 tumor to androgen was different from that of the accessory sex organs.

Animals↗
PubMed1991

Spinal kappa receptor-mediated analgesia of E-2078, a systemically active dynorphin analog, in mice.

E-2078 ([N-methyl-Tyr1, N-methyl-Arg7, D-Leu8]dynorphin A (1-8) ethylamide) is a systematically active dynorphin analog. We examined the sites of action of analgesia induced by systemic application of E-2078 compared with morphine in mice. When administered either intracerebroventricularly or intrathecally, E-2078 produced maximal dose-dependent analgesia in the tail-pinch, tail-flick and formalin tests. Its peak effect was observed 15 min after both injections, contrasted with a slow peak (120 min) by subcutaneous injection. The intrathecal site was relatively more sensitive than the intracerebroventricular site and many times more sensitive than the subcutaneous route. In contrast, morphine was equipotent when given intracerebroventricularly and intrathecally. When E-2078 was administered subcutaneously and naloxone or nor-binaltorphine were given either intracerebroventricularly or intrathecally, the analgesic action of E-2078 was most potently and totally reversed by intrathecal injection of nor-binaltorphimine. Intracerebroventricular and intrathecal injections of naloxone were equally effective for antagonism of morphine-analgesia. These data indicate that systemically administered E-2078 produces analgesia via central actions, in which the activation of the spinal kappa receptors is most important.

Analgesics↗
PubMed1991

[Clinical study on the priming principle of muscle relaxants: comparison of pancuronium with vecuronium].

The priming principle of non-depolarizing muscle relaxants was treated in this study. The subjects were 48 patients. We administered divided doses (p) and single dose (s) using pancuronium (P) and vecuronium (V), and compared the 4 groups (Pp, Ps, Vp, Vs). Pp and Vp groups received intravenous injection of 0.02 mg.kg-1 first, and 0.08 mg.kg-1 after 5 minutes. Ps and Vs groups received intravenous injection of 0.1 mg.kg-1. Relaxograph was used for monitoring muscle relaxation. First-twitch (T1) and train-of-four ratio (TR) were recorded, and the time intervals required to decrease T1 to 25% (T1-25) and 5% (T1-5) were determined. T1-25 (sec) was 126.2, 153.1, 82.7, and 132.7 in Pp, Ps, Vp, and Vs group, respectively; and T1-5 (sec) was 192.8, 229.8, 112.7, and 165.2 in Pp, Ps, Vp, and Vs group, respectively. As these values suggest, there were no significant differences between Pp and Ps group, while significant differences were noted between Vp and Vs group. The following conclusions were obtained. Clinical usefulness of the priming principle was not shown with pancuronium, but was noted with vecuronium. However, the action of vecuronium appeared rapidly after single dose, and some patients complained of dyspnea during priming. Consequently, the priming principle was not considered to be clinically beneficial.

Adult↗
PubMed1990

[Image analytic studies of melanin granules of human hairs with transmission electron micrographs].

Using electron micrographs of human hairs, we measured the minor axis and density of melanin granules by an image analyser. The melanin density of the outer hair cortex was higher than that of the inner hair cortex, and significant differences were evident especially in the minor axis and density of melanin granules among individuals. These quantitative analyses as to the minor axis and density of hair melanin granules are a reliable tool for the measurement of hair color.

Adult↗
PubMed1990

Paracrine growth stimulation of androgen-responsive Shionogi Carcinoma 115 by its autonomous subline (Chiba Subline 2).

Shionogi Carcinoma 115 cells (SC 115 cells) and Chiba Subline 2 cells (CS 2 cells) are clones of an androgen-responsive mouse tumor cell line and its autonomous subline, respectively. Since it was reported that the growth of cells from SC 115 was regulated by an androgen-induced fibroblast growth factor (FGF)-like peptide (1), the present study was aimed at examining whether a similar growth factor was secreted by CS 2 cells in the absence of testosterone. Although SC 115 cells did not grow in the serum-free medium without androgens, SC 115 cells could proliferate in mixed culture with CS 2 cells, suggesting stimulation of SC 115 cells by CS 2 cells. It was shown that CS 2 cells secreted a growth factor without the influence of testosterone, and this factor promoted the growth of SC 115 and CS 2 cells, as well as that of BALB/3T3 cells. The factor was partially purified from serum-free conditioned medium obtained from cultures of CS 2 cells. It showed an affinity for heparin, stability to heat and acid treatments, a decrease in activity when anti-basic FGF antibody was added to cultures, and an estimated molecular weight of approximately 50,000. Therefore, the factor seemed to have the nature of an FGF-like peptide. It was concluded that, in the absence of testosterone, CS 2 cells produced an FGF-like growth factor which controlled the growth of both CS 2 cells and parent SC 115 cells, in autocrine and paracrine manners, respectively.

Animals↗
PubMed1990

[Estimation of stature based on the proximal phalangeal length of Japanese women's hands].

The present authors made regression formulas to estimate the stature of Japanese women by the proximal phalangeal length of the hands of 231 Japanese women students. The stature and the proximal phalangeal length produced correlation coefficients ranging from 0.521 to 0.696, and the resulting regression formulas possessed standard errors ranging from 3.59 to 4.27 cm. Our results show that the proximal phalangeal length can be used as a reliable estimator of stature.

Adolescent↗
PubMed1990

Minaprine improves impairment of working memory induced by scopolamine and cerebral ischemia in rats.

Using a repeated acquisition procedure in a three-panel runway apparatus, the effects of minaprine on the impairment of working memory produced by scopolamine, ethylcholine aziridinium ion (AF64A) or cerebral ischemia were investigated in rats. Minaprine (3.2-32 mg/kg IP) as well as idebenone (10-100 mg/kg IP) and physostigmine (0.1-0.32 mg/kg IP) dose-dependently reduced the increase of errors (pushes made on the two incorrect panels located at each choice point) induced by 0.56 mg/kg IP scopolamine. Cerebral ischemia for 5 min caused a significant increase of errors in the runway task. Minaprine at 3.2 and 10 mg/kg administered IP immediately after blood recirculation and again 30 min before the runway test conducted 24 h after ischemia, significantly reduced increases in errors expected to occur after 5 min of ischemia. Physostigmine 0.1 mg/kg similarly attenuated the increase in errors in ischemic rats. However, minaprine at doses up to 32 mg/kg IP failed to reduce the increase of errors induced by AF64A 2.5 nmol injected into the dorsal hippocampus. These findings suggest that minaprine exerts an ameliorating effect on amnesia produced by scopolamine and cerebral ischemia, probably through mediation of its stimulant action on central cholinergic systems.

Animals↗
PubMed1990

Effect of suramin on growth of androgen-responsive mouse tumor (Shionogi carcinoma 115) and its autonomous subline (Chiba subline 2).

Suramin has been shown to inhibit the binding of various growth factors to their receptors. Shionogi Carcinoma 115 cells (SC 115 cells) and Chiba Subline 2 cells (CS 2 cells) are clones of an androgen-responsive mouse tumor cell and its autonomous subline, respectively. Since the growth of SC 115 and CS 2 cells are assumed to be regulated by their own fibroblast growth factor (FGF)-like growth factors, the present study was undertaken to examine the effect of suramin on these cells. Suramin inhibited the growth of SC 115 and CS 2 cells in a dose dependent manner. The inhibition of suramin was reversible up to 50 micrograms/ml. Suramin reversibly changed the shape of these cells from fibroblast-like to polygonal and epithelial-like ones, and inhibited 3H-thymidine incorporation into these cells which was evoked by acidic and basic FGFs, and conditioned medium obtained from CS 2 cells. The binding of 125I-basic FGF to SC 115 and CS 2 cells was inhibited by suramin. However, suramin had no effect on growth factor production and the hst-1 gene expression on CS 2 cells. In conclusion, suramin inhibited the autocrine and paracrine growth of SC 115 and CS 2 cells by blocking the binding of autocrine growth factors to their receptors.

Animals↗
PubMed1990

Analgesia produced by E-2078, a systemically active dynorphin analog, in mice.

E-2078 is a very stable dynorphin analog that has the same affinity and selectivity for opioid receptors as dynorphin-A by in vitro bioassay. In the present study, we have characterized the receptor selectivity of E-2078 in mu-, delta- and kappa-representative binding assays, and have evaluated the analgesic effect of systemically administered E-2078 by the tail pinch, tail flick and formalin tests in mice. E-2078 possessed a higher affinity for kappa-receptors than for mu- or delta-receptors in the receptor-binding assay. Dose-related, long-lasting analgesia was produced by s.c. injection of E-2078, and its peak effect was observed 2 hr after s.c. administration in all the analgesic tests. This analgesic effect was produced at doses that did not affect rotarod latency. Post-treatment with naloxone dose-dependently reversed the analgesic effects of both E-2078 and morphine, but E-2078-induced analgesia was relatively resistant to naloxone antagonism. Pre-treatment with the kappa-antagonist, nor-binaltorphimine, antagonized the analgesic effect of E-2078 but had little effect on the analgesic action of morphine. These data indicate that E-2078 is a systemically active analgesic and suggest that the activation of kappa-opioid receptors contributes to analgesia.

3,4-Dichloro-N-methyl-N-(2-(1-pyrrolidinyl)-cycloh↗
PubMed1989

Mechanisms of estrogen action on the proliferation of MCF-7 human breast cancer cells in an improved culture medium.

The effects of 17 beta-estradiol and tamoxifen (TAM) on the proliferation of responsive MCF-7 and unresponsive HBC-4 human breast cancer cells were studied in a defined culture medium containing insulin (2 micrograms/ml), transferrin (2 micrograms/ml), ethanolamine (2 microM), and selenite (25 nM). MCF-7 cells grew at a population-doubling rate of 2.0 days in serum-free medium and at a rate of 1.7 days in the medium containing 1 mg/ml of the 55-70% ammonium sulfate fraction of bovine serum or 1% dextrancoated charcoal-treated fetal bovine serum. Increasing concentrations of the ammonium sulfate fraction and/or dextran-coated charcoal-treated fetal bovine serum increasingly inhibited the growth of MCF-7 cells but did not inhibit HBC-4 cell growth, indicating that such serum preparations contain some growth inhibitor specific for estradiol-responsive MCF-7 cells. A sufficiently high concentration of exogenous estradiol (100 pM) had the dual action of neutralizing the growth inhibition by the 55-70% ammonium sulfate fraction of bovine serum and dextran-treated charcoal-treated fetal bovine: serum and enhancing directly the MCF-7 cell growth maximally 2-fold. Bovine serum albumin fraction V containing globulin remnants also inhibited growth, but globulin-free bovine serum albumin did not. Eliminating growth inhibition by the use of globulin-free bovine serum albumin enabled us to develop an ideal medium for assaying the direct effects of estradiol and TAM on MCF-7 cells. With this medium, we clearly identified (a) a direct mitogenic effect of exogenous estradiol on MCF-7 cells which was initiated at 3 pM and maximized at 0.2 to 10 nM, (b) an acute lethal effect of 1 microM TAM and its prevention by 100 pM estradiol, and (c) a nearly 50-fold increase in the concentration of exogenous estradiol (10 nM) required for maximum growth enhancement in the presence of 1 microM TAM than without TAM (0.2-0.3 nM).

Breast Neoplasms↗
PubMed1989

[The racial differences of plasminogen A gene (PLG* A) frequencies].

The present authors investigated racial differences of PLG* A frequencies by literature search. From the results of these investigations it was seen that the frequency of Mongoloids was higher than those of Negroids and Caucasoids, and the frequency of Negroids and that of Caucasoids was almost equal. There is a great variation in the distribution of PLG* A in Negroid and Caucasoid populations. Further studies are necessary to obtain more data regarding PLG* A frequency.

Asian People↗
PubMed1989

Histamine effects on pulmonary blood vessels in strangulation.

Endothelial cells of asphyxial pulmonary veins possess abundant pores and intracytoplasmic vacuoles. The present radioassay demonstrated an increase in histamine concentrations of the pulmonary tissue in asphyxia. These morphological changes, therefore, appear to represent an enhancement of the endothelial permeability induced by high histamine concentrations in blood plasma. The present immunoelectron microscopy study demonstrated heavy reactions of histamine exclusively on the endothelial surface of the asphyxial pulmonary veins. This may support the endothelial cell-dependent vasodilation mediated by histamine in asphyxial pulmonary veins.

Animals↗
PubMed1989

Hemagglutination with pseudorabies virus. Brief report.

Pseudorabies virus grown in CPK cell cultures was tested for hemagglutination (HA) with erythrocytes of a variety of species at 4 degrees C, 25 degrees C and 37 degrees C. HA was observed at all temperatures with mouse erythrocytes but not with cattle, sheep, goat, swine, cat, rabbit, guinea pig, rat, mongolian gerbil, chicken, and goose erythrocytes. Mice showed a strain variation in agglutinability of their erythrocytes, requiring selection of mice to obtain erythrocytes for HA. The HA reaction was inhibited by specific antiserum. Some factors involved in the HA and HA-inhibition (HI) were investigated and standard HA and HI tests were established. HI antibody titers of individual pig sera showed a significant positive correlation with their neutralizing antibody titers.

Animals↗
PubMed1989

Enteric solid dispersion of cyclosporin A (CyA) having potential to improve availability of CyA in rabbit.

The availability of cyclosporin A (CyA) administered as an enteric solid dispersion preparation of which the composition is CyA:HCO-60:HP-55 = 1:2:8 was evaluated in rabbits. The additives are surfactant (polyoxyethylated, 60 mumol, castor oil derivative, HCO-60) and enteric coating material (hydroxypropylmethyl cellulose phthalate, HP-55), which are generally used as pharmaceutical additives. Both the systemic and lymphatic availabilities of CyA from this solid preparation were measured in rabbits after intrastomach administration, 7 mg CyA/kg, and were compared with those from conventional oily solution, Sandimmun. The mean systemic availability of CyA from the solid preparation was 57% which is about 1.5 times greater than that obtained from Sandimmun. The amounts of CyA transferred into the thoracic lymphatics within 12 h from solid dosage form and Sandimmun are 0.62 +/- 0.16(S.D.)% and 0.13 +/- 0.05% of the administered CyA dose. These results support the usefulness of the new solid dosage form of CyA.

Animals↗
PubMed1989

Enteric solid dispersion of ciclosporin A (CiA) having potential to deliver CiA into lymphatics.

Solid dispersions composed of three components, ciclosporin A (CiA), surfactant (HCO-60) and a pharmaceutical additive, were prepared. As an additive, cellulose acetate phthalate (CAP), methacrylic acid and methacrylic acid methylester copolymer (Eudragit L-100) and hydroxypropylmethylcellulose phthalate (HP-55), which are generally used as enteric coating materials, were employed. The dissolution behavior of CiA from these enteric solid-dispersion system was studied according to the paddle method of JP XI in comparison with that of Sandimmun, an olive oily CiA solution as a reference. Solid dispersion of CiA preparation did not dissolve in the 1st test fluid (pH 1.2) in 2 h. In the 2nd fluid (pH 6.8), about 80% of CiA was dissolved within 12 min, though the dissolution rate was dependent on both the quality and quantity of the additives. An in vivo systemic and lymphatic availability study was performed with rats whose carotid artery and thoracic lymph duct were cannulated. After intrastomach administration of each CiA preparation to rats at a dose of 7 mg/kg, blood and lymph samples were collected for 6 h. One of the HP-55 preparations gave the highest plasma CiA level, Cmax = 0.99 +/- 0.20 (S.E., n = 4) micrograms/ml, and also showed the highest lymphatic availability, the percentage of dose delivered to the lymphatics in 6 h was 1.98 +/- 0.10% and the maximum lymph CiA level was 76.8 +/- 12.86 micrograms/ml. Lymphatic availability of CiA from Sandimmun was 0.78 +/- 0.11% and the peak plasma CiA level was 0.46 +/- 0.10 microgram/ml.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1989

[Behavioral pharmacological properties of the novel antidepressant paroxetine, a selective 5-HT uptake inhibitor].

The behavioral effects of paroxetine were investigated in mice and rats in comparison with imipramine and amitriptyline. 1) Locomotor activities were decreased by imipramine and amitriptyline but not by paroxetine in both animal species. 2) Paroxetine antagonized methamphetamine-induced hyperactivity in mice as did imipramine and amitriptyline. 3) Paroxetine showed a more potent antimuricidal effect in raphe-lesioned rats than imipramine and amitriptyline, and it also inhibited muricide in olfactory bulbectomized rats. 4) The immobility of rats in the forced swimming test was markedly decreased by imipramine and amitriptyline, but only slightly by paroxetine. 5) Like imipramine and amitriptyline, paroxetine potentiated the methamphetamine- or L-DOPA-induced stereotyped sniffing, and it inhibited oxotremorine-induced tremor. 6) Paroxetine antagonized reserpine-induced hypothermia, tetrabenazine-induced ptosis, and enhanced ether-induced anesthesia, all less potently than imipramine and amitriptyline. 7) The analgesic action of paroxetine was stronger than that of imipramine and amitriptyline. 8) Paroxetine did not antagonize maximal electroshock- or pentetrazol-induced convulsions and haloperidol- or THC-induced catalepsy in rats. In addition, paroxetine neither exerted muscle relaxation nor affected the shuttle-box type conditioned avoidance in rats. From these results, the behavioral effects of paroxetine, as compared with imipramine and amitriptyline, were characterized by its potent antimuricidal action in raphe-lesioned rats and its weak effect in the forced swimming test and by its less potent muscle relaxant, anticonvulsant, anticataleptic and anesthesia-potentiating actions.

Aggression↗