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Biomedical subjects

K Miyano

Publications and source records attributed to K Miyano.

At least 55 records · Page 3Linked to original sources
PubMed1991

Anti-HIV-1 activity of sulfated amphotericin B in vitro.

To reduce the toxicity of amphotericin B methyl ester (AME), which shows some anti-HIV-1 activity, sulfated amphotericin B (SAB) was prepared from amphotericin B (AB), and its anti-HIV-1 activity was examined in vitro. SAB at concentration of 7.8 micrograms/ml completely suppressed the HIV-1-induced cytopathic effect in MT-4 cells, at 3.9 micrograms/ml inhibited the expression of HIV-1 antigen in peripheral blood mononuclear cells infected with freshly isolated HIV-1 and at 22 micrograms/ml completely suppressed formation of giant cells in cocultures of MOLT-4 with MOLT-4/HIV-1 cells. Reverse transcriptase activity was inhibited by SAB, but only at higher concentrations (0.2-1 mg/ml). Furthermore, the toxicity of SAB was lower than that of AME or AB, and SAB did not affect the proliferation of MT-4 cells at concentrations up to 0.5 mg/ml. The anti-coagulant effect of SAB was 10-fold less than that of dextran sulfate (MW = 8000). The anti-HIV-1 effect of SAB is attributed to inhibition of binding of virions to target cells.

Amphotericin B↗
PubMed1991

[Prediction of the maintenance dose of vecuronium for continuous infusion].

The purpose of this study is to examine how to predict the optimal maintenance dose of vecuronium for continuous infusion, knowing the recovery time from the block induced by the first bolus injection. All patients studied were undergoing surgical procedures and were anesthetized using thiopental, vecuronium, 50% nitrous oxide and 2% enflurane in oxygen. Mechanical twitch responses of adductor pollicis muscle caused by the stimulation of the ulnar nerve supramaximally were monitored. Vecuronium concentrations in the plasma were measured using high performance liquid chromatography. The experiments consisted of two phases. Phase 1.: To demonstrate the relationship between the recovery time (T0-T25) and the maintenance dose. Thirty patients were studied in this phase. A bolus injection was given as the first dose (1.5 mg.kg-1). During the recovery from the first block, recovery time (T1) was measured and the second dose (2 mg) was injected at the T25 (25% control twitch height). After waiting the recovery until the T25, the third dose (2 mg) was injected. The duration (T2) (min) between the second and the third injection was measured. The maintenance dose-recovery time curve was obtained. Y = 52.70.exp (-17.50 X) + 1224.53.exp (-224.27X), X = recovery time (min), Y = maintenance dose (mg.hr-1). Phase 2.: Thirty patients were studied in this phase. Patients received infusions after the bolus injection. The infusion rates were obtained from the maintenance dose-recovery time curve.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1991

[Reactivity of sevoflurane with carbon dioxide absorbents--comparison of soda lime and Baralyme].

The reactivity of sevoflurane with carbon dioxide absorbents, soda lime and Baralyme which are commercially available carbon dioxide absorbents, was studied. A closed circuit system which was made only for this investigation was set up without rubber. Sevoflurane 5% was circulated for 17 hours. The circulated gas was analyzed by gas chromatography (GC) and degradation products were identified by a gas chromatography-mass spectroscopy (GC-MS) as fluoromethyl 2-methoxy-2, 2-difluoro-1-(trifluoromethyl) ethyl ether, fluoromethyl 2-methoxy-2-fluoro-1-(trifluoromethyl) vinyl ether, and its isomer. These degradation products of sevoflurane from soda lime and Baralyme were the same substances. The rate of degradation by soda lime was 0.88% +/- 0.306, while that by Baralyme was 3.40% +/- 0.501. Baralyme decomposed sevoflurane about four times more than soda lime. There are two possible explanations for these results. One is the Baralyme contains more potassium hydroxide than soda lime. The other is that soda lime absorbs sevoflurane more because it contains more silica.

Absorption↗
PubMed1990

[Effects of dopamine and dobutamine on hepatic circulation and metabolism in hemorrhagic hypotensive pigs].

Effects of dopamine and dobutamine in a dose of 5, 10 or 20 micrograms.kg-1.min-1 on hepatic blood flow and hepatic metabolism were studied in normotensive and hemorrhagic hypotensive (MAP 50mmHg) pigs during 1 MAC enflurane anesthesia. PaCO2 was maintained within a physiological range (30-35mmHg) by controlled ventilation. Portal venous blood flow and hepatic arterial blood flow were measured by ultrasonic blood flowmetry. Hepatic oxygen supply and consumption were calculated from blood flows and oxygen contents. Each dose of dopamine and dobutamine did not change significantly MAP and cardiac output in both normotensive and hypotensive pigs. In the normotensive state, dopamine increased significantly total hepatic blood flow and hepatic oxygen supply, by raising portal venous blood flow, but dobutamine did not increase them. Also in the hemorrhagic hypotensive state, dopamine increased significantly total hepatic blood flow and hepatic oxygen supply by increasing both portal venous blood flow and hepatic arterial blood flow, but dobutamine did not produce similar increase. On the other hand, there was no significant change in hepatic oxygen consumption in both normotensive and hypotensive pigs by dopamine and dobutamine administration. These results suggest that dopamine is superior to dobutamine for hepatic circulation and hepatic metabolism especially in the hemorrhagic hypotensive state.

Animals↗
PubMed1989

[Inhibitory effect of inositol hexasulfate and inositol hexaphosphoric acid (phytic acid) on the proliferation of the human immunodeficiency virus (HIV) in vitro].

The monosaccharide substances inositol hexasulfate (IHS) and inositol hexaphosphoric acid (Phytic acid, IHP) were investigated for their antiviral effect on the human immunodeficiency virus (HIV) in vitro. In MT-4 cells IHS completely inhibited the cytopathic effect of HIV and the HIV specific antigen expression at a concentration of 1.67 mg/ml. IHP moderately inhibited both of HIV effects as mentioned above.

Antiviral Agents↗
PubMed1989

[Anatomical study of the superior jugular bulb by use of high-resolution computed tomography].

Using high-resolution computed tomography, the relationship between the superior jugular bulb and the tympanic cavity was analysed in 40 subjects. Until now, the superior jugular bulb was thought to lie below the floor of the hypotympanum, however, the following observations were made from this study: 1) In 48 (60%) out of 80 temporal bones (40 cases), the top of the superior jugular bulb was situated in the higher level than the floor of the hypotympanum. 2) In 9 cases, the jugular bulb was separated from the tympanic cavity by only thin bony wall. This finding was noticed on the right side in 8 cases and was bilateral in a case. 3) In 21 cases (52.5%), the right jugular bulb was situated in higher level than the left, and the reverse finding was noticed only in 4 cases (10.0%). The reason why the right jugular bulb is frequently higher than the left was thought to be related to its function. Namely, the jugular bulb is useful to absorb the pulsation of the carotid artery, therefore, it was considered that the anatomical and physiological differences between the right and left carotid arteries induce the asymmetry of the jugular bulbs.

Chronic Disease↗