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Biomedical subjects

M Asano

Publications and source records attributed to M Asano.

At least 379 records · Page 21Linked to original sources
PubMed1989

Effects of intravenously administered human atrial natriuretic peptide on elevated blood pressure during surgery.

The effect of human atrial natriuretic peptide (hANP) on blood pressure (Bp) was evaluated in 11 patients who had elevated systoric Bp of over 150 mmHg during surgery. A bolus injection of 50 microg or 100 microg of hANP decreased Bp with an immediate response by 27.6 +/- 3.1 mmHg (P < 0.001) or 40.7 +/- 4.2 mmHg (P < 0.001), respectively, accompanying with tremendously increased urine output. Heart rate and PaO2 were not altered. Thus, a intravenous bolus injection of hANP is an useful therapeutic tool for the treatment of acutely elevated Bp during anesthesia.

Journal Article↗
PubMed1989

Mutagenesis of human granulocyte colony stimulating factor.

To define the structure-function relationship, we have made a number of mutants of human granulocyte colony-stimulating factor (hG-CSF) by in vitro mutagenesis. The results indicate that most of the mutations located in the internal and C-terminal regions of the molecule abolished the activity, whereas the mutants without N-terminal 4, 5, 7, or 11 amino acids retained the activity. N-terminal amino acids were also altered by cassette mutagenesis using a synthetic oligonucleotide mixture. Among them, KW2228, in which Thr-1, Leu-3, Gly-4, Pro-5 and Cys-17 were respectively substituted with Ala, Thr, Tyr, Arg and Ser, showed more potent granulopoietic activity than that of intact hG-CSF both in vitro and in vivo.

Amino Acid Sequence↗
PubMed1989

High performance liquid chromatography of biological polyamines using immobilized enzyme as post-column reactor followed by electrochemical detection.

A novel analytical method for biological polyamines (putrescine, spermidine and spermine) was developed. Polyamines were separated by ion-pair reversed phase chromatography using a polymer-based octadecyl bonded column. A polyamine oxidase immobilized column worked effectively as a post-column reactor to convert polyamines to hydrogen peroxide which was eventually detected by electrochemical oxidation on platinum electrode. This method required neither tedious derivatization nor gradient elution, permitting us to perform simple and rapid analysis of polyamines. The detection limits were 0.3, 0.6, and 4 pmol injected for putrescine, spermidine, and spermine, respectively with a linear range of two to three orders of magnitude. Chromatograms obtained with samples from human urine and rat brain homogenates demonstrated the high sensitivity and selectivity of the method.

Animals↗
PubMed1989

Determination of paraquat in raw and formalin-fixed tissues by electron spin resonance (ESR) spectroscopy.

ESR method was applied to determine paraquat levels in fresh and formalin-fixed tissues. Paraquat was converted to paraquat radical by adding sodium dithionite to tissue homogenates and detected by ESR. Paraquat levels of more than 0.2 micrograms/ml homogenate could be quantified with 0.1 ml of the homogenate. The use of manganese ions for standardization of paraquat signal enabled much more accurate ESR measurements because this ion was quite stable and its signal did not overlap that of paraquat. Even with tissues fixed in formalin, tissues paraquat levels were measureable after removing formalin from the tissue extract. This fact was verified by studying two cases; the tissues were kept in formalin for 1.5 years in case 1 and for 6.5 years in case 2. In both cases, the paraquat contents in tissues were 0.02-0.08 micrograms/g. In this way ESR is one of the most suitable methods in determining low levels of paraquat in tissues even after they were preserved in formalin for a long time.

Adult↗
PubMed1989

Rapid isolation with Sep-Pak C18 cartridges and wide-bore capillary gas chromatography of some butyrophenones.

A simple and rapid method for isolation of five butyrophenones with Sep-Pak C18 cartridges from human samples, and their wide-bore capillary gas chromatography (GC), are presented. The GC was made by both flame ionization and electron capture detections. The drugs contained in alkaline samples were directly applied to the cartridges and eluted with chloroform/isopropanol (9:1). The recoveries with use of the cartridges were excellent for most drugs in both urine and plasma samples. We can recommend the Sep-Pak C18 cartridges for isolation of butyrophenones because of simplicity and rapidity, and also wide-bore capillary GC because of high sensitivity and low decomposition of drugs during passage through the column.

Antipsychotic Agents↗
PubMed1989

Acute necrotizing encephalopathy with widespread edematous lesions of symmetrical distribution.

A 67-year-old Japanese woman with liver cirrhosis was affected by an unusual acute progressive encephalopathy, presenting mental confusion and slurred speech as its initial symptoms. She died in profound coma, following the entire course of 17 days. Autopsy disclosed bilateral symmetrical, widespread, edematous and necrotic lesions, their centers being located in the basal ganglia, diencephalon and midbrain, and their peripheries expanding into the cerebral white matter, cerebellum, pons and medulla. Diapedesis of erythrocytes and serum plasma was conspicuous, in contrast to paucity of capillary proliferation. Although the lesions were somewhat similar to those of Wernicke's and Leigh's encephalopathies, they were considered to be representative of a more acute metabolic disorder distinct from the latter conditions.

Acute Disease↗
PubMed1989

Detection of high levels of immunoreactive human beta-1 interferon in sera from HIV-infected patients.

We have examined human interferon beta-1 (HuIFN-beta 1) levels in the sera from patients with various diseases by using a newly developed highly sensitive enzyme-linked immunosorbent assay system (ELISA). High levels of HuIFN-beta 1 were detected in the sera from Human Immunodeficiency Virus-I (HIV-I) infected patients, especially of asymptomatic carriers. The serum level of HuIFN-beta 1 may be a good indicator of HIV-I infection and of other immunological disorders.

AIDS-Related Complex↗
PubMed1989

In vivo release of cisplatin from a needle-type copolymer formulation implanted in rat kidney.

Cisplatin, cis-dichlorodiamine platinum (II), was incorporated in a needle-type copolymer formulation (0.8 mm diameter, 6 mm long) by radiation-induced polymerization. The copolymer used was copoly(diethylene glycol dimethacrylate/polyethylene glycol #600 dimethacrylate, 80/20 vol%). This copolymer, containing 6 mg of cisplatin, was implanted into the kidney of adult male Wistar rats (420 +/- 20 g). A total of 70 d was required for 100% release of cisplatin in vivo. The kidney tissue surrounding the formulation was strongly necrotized by the action of cisplatin. Two layers of necrosis could be distinguished: necrotic tissue surrounding the formulation and necrobiotic tissue surrounding the necrotic tissue. The amount of necrotic tissue changed markedly over time, but no change was apparent in the amount of necrobiotic tissue. The maximal amounts of necrotized tissue were observed 14 d after implantation: 3100 microns and 600 microns thick for the necrotic and necrobiotic tissues, respectively.

Animals↗
PubMed1989

In vivo characteristics of low molecular weight copoly (D,L-lactic acid) formulations with controlled release of LH-RH agonist.

Amorphous and crystalline copolymers with a relatively low molecular weight of 1800 were synthesized by direct copolycondensation of D-lactic acid and L-lactic acid in the absence of a catalyst, to evaluate their in vivo capabilities as biodegradable carriers for drug delivery systems. A luteinizing hormone-releasing hormone agonist, des-Gly10-(D-Leu6)-LH-RH ethylamide, was incorporated in a fine cylindrical copolymer formulation, under melt-pressing technique, a mild heat-pressure condition. This formulation was implanted subcutaneously in the back of male rats. The rate of in vivo degradation of amorphous copolymer was much faster than that of crystalline copolymer. Contrary to this tendency, the in vivo release of the drug from this amorphous formulation was held constant over a longer period, compared with the crystalline formulation. This can be closely related to the difference in dispersion of the drug in the formulation.

Animals↗
PubMed1989

Decrease in alpha 1-adrenoceptor reserve in mesenteric arteries isolated from spontaneously hypertensive rats.

The characterization of alpha-adrenoceptor-mediated contractile responses and the effects of the calcium channel blocker nifedipine on these responses were investigated in mesenteric arterial strips from 13-week-old male spontaneously hypertensive rats (SHR) and normotensive Wistar-Kyoto rats (WKY). Contractile responses to the alpha-adrenoceptor agonists phenylephrine and clonidine were mediated through the activation of alpha 1-adrenoceptors. The dose producing a half-maximum response (ED50) for the agonists was higher in SHR than in WKY. Affinities of alpha 1-adrenoceptors were similar between the two strains. When arterial strips from both strains were treated with the same concentration of phenoxybenzamine, the maximum response to each agonist was weaker in SHR. The alpha 1-adrenoceptor occupancy-response relationship for phenylephrine was hyperbolic and less steep in SHR, while the relationship for clonidine was linear in SHR but not in WKY. Alpha 1-adrenoceptor occupancy at a half-maximum response to each agonist was greater in SHR. Nifedipine inhibited the maximum responses to the agonists more profoundly in SHR than in WKY. This inhibition was greater in the response to clonidine than in the response to phenylephrine in both strains. When the maximum response to phenylephrine was reduced to the same extent in both strains by treatment with different concentrations of phenoxybenzamine, the responses to phenylephrine were more susceptible to inhibition by nifedipine. Under these conditions, the effects of nifedipine were similar between SHR and WKY. These results suggest that alpha 1-adrenoceptor reserve is reduced in SHR mesenteric artery compared with WKY, which may be responsible for the greater inhibition by nifedipine of the alpha 1-adrenoceptor-mediated contractions in SHR.

Adrenergic alpha-Agonists↗
PubMed1989

Decreased arterial responsiveness to multiple cyclic AMP-generating receptor agonists in spontaneously hypertensive rats.

1. Arterial relaxant responses via beta-adrenoceptors are decreased in spontaneously hypertensive rats (SHR) when compared with normotensive Wistar-Kyoto rats (WKY). Recent studies from this laboratory proposed that a reduced function of stimulatory guanosine 5'-triphosphate (GTP)-binding protein (Gs) is responsible for the decreased beta-adrenoceptor responsiveness in the SHR femoral artery. Since the Gs is common to all tissues, as opposed to receptors, which are tissue specific, the reduced function of Gs should lead to resistance to multiple receptors that act by activating adenylate cyclase (AC). To test this hypothesis, relaxant responses via beta-adrenoceptors, A2-adenosine, H2-histamine and D1-dopamine receptors were compared between arterial strips from 13 week-old WKY and age-matched SHR. 2. The relaxant responses to noradrenaline (NA) via beta-adrenoceptors in femoral, mesenteric, renal and carotid arteries were significantly decreased in the SHR, when compared with the respective arteries from WKY. 3. However, under the same conditions arterial relaxant responses to forskolin, an activator of AC, were not significantly different between the WKY and SHR. 4. The relaxant responses due to activation of A2-adenosine. H2-histamine and D1-dopamine receptors were significantly decreased in the SHR arteries. 5. Nitroprusside and nifedipine, agents which are independent of the Gs.AC system, produced similar arterial relaxations in the WKY and SHR. 6. These results support the hypothesis that a reduced function of Gs in the SHR is responsible for the decreased arterial responsiveness to a variety of receptor agonists whose mechanism of action involves AC activation.

Animals↗
PubMed1989

Antibiotic susceptibility of serotype 2 and 5 strains of Actinobacillus (Haemophilus) pleuropneumoniae isolated from swine from 1974 to 1986.

Antibiotic susceptibility of 129 isolates of Actinobacillus (Haemophilus) pleuropneumoniae was examined. All the strains were isolated in 1974 to 1986 from the nasal cavities of swine housed on 35 farms in 11 prefectures of Japan. All 28 strains of serotype 2 isolated before 1984 were susceptible to 10 antibiotics used. In contrast, more than one-half of 79 strains of serotype 2 isolated in 1985 and 1986 were resistant to aminoglycosides, tetracycline, tylosin and carbadox, and most of them showed multiple drug resistance. All the 22 strains of serotype 5 were isolated only in 1985 and 1986, and almost all the isolates were susceptible to the antibiotics used in this study. Distribution of minimal inhibitory concentration of serotype 2 strains were bimodal to aminoglycosides, tetracycline, or tylosin. The present results showed that the number of antibiotic resistant strains of A. pleuropneumoniae has increased recently in Japan.

Actinobacillus↗
PubMed1989

[Application of CaO-P2O5-MgO-SiO2-CaF system glass ceramics to periodontal therapy. Histopathological observation after implantation in furcation bony defect in monkeys].

This study was carried out in order to determine the efficacy of CaO-P2O5-MgO-SiO2-CaF system glass ceramics, which are made as implant materials, for treatment of furcation lesions. Glass ceramic granules were implanted in artificial class II furcation bony defects in monkeys. As controls, non-implanted sites were preserved. Radiographic and various clinical examinations were performed before surgery and at 0, 2, 4 and 8 weeks after implantation. Two, 4 and 8 weeks after implantation, two monkeys were sacrificed and the mandibles were sectioned for histopathological observation. The results obtained were as follows; 1. During the experiment, no clinical problems or abnormal response at the sites of glass ceramic implantation were observed. 2. In clinical observation, no remarkable differences were obtained between control sites and implanted sites. 3. Two and 4 weeks after surgery, remarkable regeneration of bone was shown in the implanted sites. However 8 weeks after surgery, the difference between implanted and control sites was not so clear.

Acrylic Resins↗
PubMed1989

[Clinical and histopathological observation of CaO-P2O5-MgO-SiO2-CaF system glass ceramic tooth implants in monkeys].

The present study was undertaken to determine the biocompatibility of a newly-developed CaO-P2O5-MgO-SiO2-CaF system glass ceramic tooth implant. Two adult male monkeys were selected and 12 weeks after extraction of M1 and P1, 8 glass ceramic teeth were implanted into alveolar bone. At 1 week after implantation, 6 teeth were allowed occlusal function, and 2 teeth were left free from occlusion as control teeth. The implants were observed for 4-12 weeks and examined histopathologically. The results were as follows: 1. Seven implanted teeth were well maintained clinically, and only one tooth was lost after 5 weeks. 2. In histopathological observation, implanted teeth were surrounded by bone, and connected by bonyankylosis. At cervix of dental implant, connective tissue as also attached firmly to implanted tooth surfaces and epithelial attachment was observed. 3. Although these implants were allowed occlusal function at an early stage (1 week after implantation), osteogenesis around implants was not disturbed. These results suggest that the new glass ceramic implant has good biocompatibility and is useful as an implant tooth.

Acrylic Resins↗
PubMed1989

[Objective examination and diagnosis of bruxism. 1. New device for recording muscle activity and tooth contacts during sleeping at home].

The purpose of this study was to make an objective diagnosis of bruxism using a new recording system by observation during sleeping at home. The system was composed of a portable recorder for monitoring bruxism at home and an analyzing device for recalling the data later in laboratory. Muscle activity as recorded by EMG, occlusal tooth contacts were monitored by microvibration pick-up, and grinding sounds were recorded by a small microphone, simultaneously. These were printed on the one recording paper by playing back the tape. Six subjects were selected and were monitored individually for five nights with this new system at home. Records were transcribed and analyzed in the laboratory. As a result, nocturnal muscle activity, occlusal tooth contacts, and grinding sounds were recorded and analyzed efficiently with system. This new system is considered in useful for the investigation and diagnosis of bruxism in periodontal disease.

Bruxism↗