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Biomedical subjects

K Furusawa

Publications and source records attributed to K Furusawa.

At least 73 records · Page 4Linked to original sources
PubMed1991

The innervation of the levator veli palatini muscle by the glossopharyngeal nerve.

We developed a novel method which enables bloodless exposure of the levator veli palatini muscle in rat in order to investigate the physiological properties of this muscle. The levator veli palatini muscle which is innervated by a branch of the glossopharyngeal nerve showed rhythmic spontaneous movement in rats. Cutting the branch supplying LVP of the glossopharyngeal nerve caused cessation of the spontaneous movement of the levator veli palatini muscle. The spontaneous discharges of the glossopharyngeal nerve were synchronized with those of the phrenic nerve. A mixture of 95% oxygen and 5% room air influenced the efferent discharges from the branch of the glossopharyngeal nerve supplying the levator veli palatini muscle. These findings indicate that the motor nerve supply to the levator veli palatini muscle is the glossopharyngeal nerve, and the levator veli palatini muscle is related to the respiratory system, in particular with inspiration in rats.

Action Potentials↗
PubMed1991

Nucleotide specificity of the enzymatic and motile activities of dynein, kinesin, and heavy meromyosin.

The substrate specificities of dynein, kinesin, and myosin substrate turnover activity and cytoskeletal filament-driven translocation were examined using 15 ATP analogues. The dyneins were more selective in their substrate utilization than bovine brain kinesin or muscle heavy meromyosin, and even different types of dyneins, such as 14S and 22S dynein from Tetrahymena cilia and the beta-heavy chain-containing particle from the outer-arm dynein of sea urchin flagella, could be distinguished by their substrate specificities. Although bovine brain kinesin and muscle heavy meromyosin both exhibited broad substrate specificities, kinesin-induced microtubule translocation varied over a 50-fold range in speed among the various substrates, whereas heavy meromyosin-induced actin translocation varied only by fourfold. With both kinesin and heavy meromyosin, the relative velocities of filament translocation did not correlate well with the relative filament-activated substrate turnover rates. Furthermore, some ATP analogues that did not support the filament translocation exhibited filament-activated substrate turnover rates. Filament-activated substrate turnover and power production, therefore, appear to become uncoupled with certain substrates. In conclusion, the substrate specificities and coupling to motility are distinct for different types of molecular motor proteins. Such nucleotide "fingerprints" of enzymatic activities of motor proteins may prove useful as a tool for identifying what type of motor is involved in powering a motility-related event that can be reconstituted in vitro.

Actins↗
PubMed1991

Drug effects on cognitive function in mice determined by the non-matching to sample task using a 4-arm maze.

A new task for the analysis of drug effects on the cognitive function in mice was investigated using a 4-arm maze with three selectable arms. Each trial consisted of a forced run either to the right or left arm containing a food pellet, which was changed for each trial, followed by a free-choice run after a delay (0-120 sec). The correct response was to turn to the arm 180 degrees opposite from the forced one. Entrance into the center arm in the free-choice run, which was called the non-reward response, was not reinforced at any time. As the delay became longer, correct responses decreased, but non-reward response errors remained unchanged in the well-trained mice. Without increasing the non-reward response, scopolamine and atropine, but not methylscopolamine, decreased the correct response in a delay-dependent manner at a low dose range, while diazepam did so in a delay-independent manner. Physostigmine ameliorated scopolamine-induced impairment in performance, but had less effect on the delay-induced decrease in the correct response. Other tested drugs (chlorpromazine, haloperidol, apomorphine, phentolamine, propranolol, lithium chloride, ketamine, and caffeine) had no significant effect on performance. These results suggest that CNS muscarinic blockades and diazepam treatment selectively attenuate working memory in different ways.

Animals↗
PubMed1991

Chemical synthesis of branched RNAs: a new method for construction of synthetic units for branched RNAs by use of 2'-phosphorylation on the basis of steric control.

A 3',5'-unprotected 2'-O-bis(tert-butoxy)-phosphinyl-6-N-benzoyladenosine derivative was prepared as a key intermediate for the synthesis of branched RNAs, and used for construction of building units from which chain elongation in any of 2'-, 3'-, and 5'-directions would be possible. From this synthetic intermediate, 2'-phosphorylated ApC dimer was also synthesized.

Base Sequence↗
PubMed1990

Necrotizing buccal and cervical fasciitis.

A bite wound led to necrotizing fasciitis in the temporal space, the lateral pharyngeal space and the carotid sheath, indicative of a Streptococcus and Bacteroides infection, and was successfully treated with repeated incisions, radical debridement and antibiotic therapy.

Aged↗
PubMed1990

Effects of qing-fei-tang on the airway inflammation and clearance.

Qing-Fei-Tang, a Chinese blended medicine, inhibited the release of slow reacting substance of anaphylaxis (SRS-A) from passively sensitized guinea pig lung after antigen challenge. Qing-Fei-Tang also suppressed the chemiluminescence of oxygen radicals when healthy human leukocytes were stimulated by opsonized zymosan. In rabbits, Qing-Fei-Tang increased the output volume and fatty acid contents in respiratory tract fluid. In the bronchitic rabbits, 6 weeks administration of Qing-Fei-Tang restored the decreased amount of saturated fatty acid in the sputa, and histological examinations revealed an amelioration of the inflammation of lung tissues. In pigeons, Qing-Fei-Tang facilitated tracheal mucociliary transport. Accordingly, Qing-Fei-Tang seems to exert effectiveness via its multiple mechanisms.

Animals↗
PubMed1990

Effects of psychoactive drugs on the conflict behavior under operant situation in Mongolian gerbils (Meriones unguiculatus).

Effects of diazepam, pentobarbital, morphine, ethanol, caffeine, and nicotine on the conflict behavior established under a MULT FR 20/FR 20 punishment schedule of food reinforcement were investigated in Mongolian gerbils. Fourteen out of 17 gerbils learned lever-press response for food within 15 sessions of training under FR 20 schedule. Although high voltage of electric shock (125-225 V) was required for attaining lever-press suppression, all 14 gerbils exhibited stable conflict behavior, i.e., showing high response rate of 20-30 responses/min in the safety period and low response rate of 0-3 responses/min in the alarm period. Diazepam, a prototype of the antianxiety drugs, increased the response rate in the alarm period. The anticonflict effect was also observed after administration of either pentobarbital or ethanol. On the other hand, morphine suppressed lever-pressing in a nonspecific manner. Caffeine tended to attenuate the conflict behavior, but nicotine had no such effect. These results suggest that the effects of psychoactive drugs on the conflict behavior of gerbils are almost identical with those in mice and rats.

Animals↗
PubMed1989

Electrical phenomena at the surface of phospholipid membranes relevant to the sorption of ionic compounds.

The change in electrostatical potential-profile across the phospholipid membranes caused by the binding or sorption of ionic compounds (metal cations, ionic surfactants, lipid-soluble ions, and ionophore-metal complexes) can be estimated by the direct measuring method (combination of zeta potential of lipid vesicles and surface potential of lipid monolayer). The analysis of the data by a simple electrical double layer theory reveals the binding/sorption location of these ions. The coexistent effect of metal ions and lipid-soluble ions on the sorption behavior is described from the interfacial electrochemical view point. The coagulation of lipid vesicles caused by those ionic compounds is also discussed.

Ions↗
PubMed1989

[Enhanced percutaneous absorption of formoterol fumarate via pulsed iontophoresis. II. Effect of polarity, pulse frequency and duty].

To clarify the effect of polarity, pulse frequency and duty on the iontophoretic transport of formoterol fumarate (FF), in vitro and in vivo studies were performed with guinea pigs. In the in vitro studies, the flux at steady state was enhanced by the factor 7.61 with anodal iontophoresis in comparison with control, whereas, with cathodal iontophoresis it was restrained by the factor 0.79. When pulse frequency was varied from 0 to 40 kHz, the flux at steady state was enhanced with an increase in pulse frequency. In the in vivo studies with varying the duty of pulse potential from 10 to 100%, the maximum plasma concentration of FF was obtained at a 30% duty. In contrast, the plasma concentration of FF achieved at 100% duty was not high. With stripped skin, no significant difference in the plasma concentration of FF was shown between iontophoresis and control. Consequently, it is suggested that iontophoresis contributes to FF penetration across stratum corneum.

Animals↗
PubMed1989

Protective effect of surface-active phospholipids against the acid-inducing inhibition of the tracheal mucociliary transport.

Little is known about the physiological role of surface active phospholipids (SAP) in the central respiratory tract. In the present study, the effect of SAP on acid-inducing inhibition of particle transport by the tracheal mucociliary function was investigated in unanesthetized pigeons. SAP and acids were directly nebulized to the surface of the trachea. The composition of SAP was based on that of the pulmonary surfactant. The experiment was carried out under application of acetylcholine providing a constant mucociliary transport. SAP significantly diminished HCl- and H2SO4-inducing inhibitions of the mucociliary transport. Benzalkonium chloride also reduced the inhibition. The results suggest that SAP may be a protecting factor of the mucociliary clearance and that SAP may be connected with hydrophobicity not only of the alveolar surface but of the tracheal epithelium.

1,2-Dipalmitoylphosphatidylcholine↗
PubMed1987

Secretomotor and mucolytic effects of mabuterol, a novel bronchodilator.

Action of mabuterol, a novel bronchodilator, on the respiratory secretion system was investigated, and the following effects were confirmed: 1) increase of output volume, amounts of protein and pulmonary surfactant in respiratory fluid; 2) decrease of sputum viscosity; 3) fragmentation of the sputum structure and 4) promotion of the mucociliary transport of particles. The results in the present study may, at least partly, substantiate clinical efficacy such as improvement of pulmonary function, favourable effects on expectoration and amelioration of symptoms observed in patients with chronic obstructive pulmonary disease.

Adrenergic beta-Agonists↗
PubMed1987

[Effects of psychotropic drugs by the cumulative-dosing procedure on lever-press and shuttle discrete avoidance responses in mice].

Effects of psychotropic drugs on lever-press and shuttle discrete avoidance responses were investigated by the cumulative-dosing procedure in mice. For cumulative determination, doses of drugs were given 3 times every 1 h within the same session. As a control, the intermittent-dosing procedure in which a single dose was given twice a week was also tested. Cumulative-dosing of chlorpromazine, haloperidol, tetrabenazine, diazepam, and pentobarbital all produced dose-dependent suppression in lever-press and shuttle avoidance responses. Each cumulative dose-effect curve for chlorpromazine and haloperidol in both avoidance responses, and for tetrabenazine and diazepam in lever-press avoidance response was almost identical with that obtained by the intermittent dosing. The cumulative effects of tetrabenazine in shuttle avoidance response and pentobarbital in both avoidance responses were weak. In contrast, diazepam suppressed shuttle avoidance response in the cumulative dosing, but not in the intermittent dosing. Cumulative dosing of methamphetamine and morphine increased response rates without marked changes in avoidance rates in the shuttle avoidance response. Cumulative dosing of methamphetamine was less effective than the intermittent dosing. In contrast, the cumulative dose-effect curve for morphine was almost identical with that obtained by the intermittent dosing. The present results indicate that the cumulative-dosing procedure may be applicable to the drug evaluation in lever-press and shuttle avoidance responses.

Animals↗
PubMed1985

Complete co-purification of choline kinase and ethanolamine kinase from rat kidney and immunological evidence for both kinase activities residing on the same enzyme protein(s) in rat tissues.

Choline kinase and ethanolamine kinase were completely co-purified from rat kidney cytosol through acid treatment, ammonium sulfate fractionation, DEAE-cellulose column chromatography, Sephadex G-150 gel filtration followed by choline-Sepharose affinity chromatography. The final preparation appeared to be highly homogeneous with respect to both native and sodium dodecyl sulfate-polyacrylamide gel electrophoresis (Ishidate, K., Nakagomi, K. and Nakazawa, Y. (1984) J. Biol. Chem. 259, 14706-14710). Throughout the purification steps, the ratio of ethanolamine kinase activity to choline kinase activity was almost constant in a range of 0.3-0.4, which strongly indicated that, in rat kidney, both activities could reside on a single enzyme protein. The rabbit polyclonal antibody raised against highly purified rat kidney choline (ethanolamine) kinase protein inhibited both choline and ethanolamine kinase activities in a parallel manner in crude enzyme preparations not only from rat kidney, but also from rat liver, lung and intestinal cytosols. The results, together with our previous findings, suggested strongly that, in rat tissues, at least large portions of both kinase activities are present on the same enzyme protein(s). The kinetic properties of both kinase reactions with the highly purified kidney enzyme were compared in some detail and the overall result suggested that choline kinase and ethanolamine kinase activities may not have a common active site on a single enzyme protein.

Adenosine Triphosphate↗
PubMed1985

Synthesis of cyclic silyl nucleosides having bulky groups on the silicon atom.

Synthesis of cyclic silyl nucleosides having bulky tert-butyl groups on the silicon atom has been investigated. Cyclic silyl deoxyribonucleosides having one tert-butyl group on the silicon atom was obtained without difficulty in the standard silylation reaction using dichlorosilane and imidazole. However, under similar conditions the reaction with di-tert-butyldichloro-silane proceeded only slowly by virtue of steric hindrance. The reaction has been largely improved by the use of 1-hydroxy-benzotriazole as a catalyst for silyl transfer and silver salts of acids to generate silylating reagents of high reactivity.

Indicators and Reagents↗
PubMed1984

Deoxyribonucleoside-3',5'-cyclic silanediyl derivatives: formation and properties.

Formation of 3',5'-O-(dialkylsilanediyl)deoxyribonucleosides was studied. Treatment of deoxythymidine in DMF with bifunctional silylating reagent such as di-t-butyldichlorosilane and diisopropyldichlorosilane in the presence of imidazole gave the expected silanediyl derivatives. The structure was confirmed mainly by NMR spectroscopy. The stability of these cyclic silyl derivatives toward hydrolysis is also described.

Deoxyribonucleosides↗