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Biomedical subjects

Y Yasuda

Publications and source records attributed to Y Yasuda.

At least 379 records · Page 21Linked to original sources
PubMed1982

Comparison of the absorption, excretion, and metabolism of suxibuzone and phenylbutazone in humans.

The absorption, excretion, and metabolism of a single oral dose of suxibuzone, a new nonsteroidal anti-inflammatory agent, in healthy male volunteers were compared with those of phenylbutazone. After oral administration of either suxibuzone or phenylbutazone, phenylbutazone, oxyphenbutazone, and gamma-hydroxyphenylbutazone were found in the plasma; phenylbutazone was the main metabolite of suxibuzone and phenylbutazone. In the urine, p-gamma-dihydroxyphenylbutazone and several glucuronide conjugates also were found. Spectrometric and/or enzymatic analysis showed that these glucuronide conjugates were suxibuzone glucuronide, 4-hydroxymethylphenylbutazone glucuronide, 4-hydroxymethyloxyphenbutazone glucuronide, oxyphenbutazone glucuronide, and phenylbutazone glucuronides (two types: O-glucuronide and C-4-glucuroxide) after suxibuzone administration, and oxyphenbutazone glucuronide and phenylbutazone glucuronide after phenylbutazone administration. The conjugates specific to suxibuzone administration, suxibuzone glucuronide, 4-hydroxymethylphenylbutazone glucuronide, and 4-hydroxymethyloxyphenbutazone glucuronide, were excreted in the first 6 hr urine. These findings and the pharmacokinetics of these metabolites in the plasma and urine show that suxibuzone is a prodrug of phenylbutazone.

Adult↗
PubMed1982

Quantitative structure-inhibitory activity relationships of phenols and fatty acids for Bacillus subtilis spore germination.

Phenols and fatty acids were found to inhibit L-alanine-initiated germination of Bacillus subtilis spores without altering their heat resistance. Inhibitory effect was defined as the concentration necessary to cause 50% inhibition of the germination rate. The quantitative structure-inhibitory activity relationships for 39 phenols and 7 fatty acids were analyzed. The pH dependency of inhibition showed that the nonionized form of the molecule was responsible for inhibition. Hydrophobicity, which was expressed by the partition coefficient or the distribution coefficient of the compounds, was important for inhibition. In addition to hydrophobicity, the electronic effect, which was expressed by the dissociation constant, played a partial role in phenols. The correlation equation of the fatty acids was similar to those of the alcohols and other hydrophobic compounds, which had been reported earlier. That of the phenols, however, appeared to be different, indicating a different and more complex mechanism of inhibition. The type of inhibition by both compounds was mixed rather than competitive or noncompetitive.

Alanine↗
PubMed1982

A selective isolation procedure for Micromonospora.

A selective medium containing 25 to 50 micrograms per ml of tunicamycin was devised to isolate micromonosporae from soil samples, making possible simple, preferential isolation of a variety of Micromonospora. When a large amount of Gram-negative bacteria was present in a sample, alkaline treatment (0.01 N NaOH, 5 approximately 10 minutes at 15 degrees C) wa employed to reduce the numbers. Using the tunicamycin agar medium, 1,585 strains of presumably different micromonosporae were obtained from 400 soil samples collected from various regions around the world. In average, 4 different Micromonospora strains could be located from one soil sample. This tunicamycin method made possible a concentrated screening method for new antibiotics from Micromonospora.

Bacteria↗
PubMed1982

[Interactions between buprenorphine, narcotic analgesic, and centrally acting drugs in prolongation of halothane-induced sleeping and analgesia (author's transl)].

Interactions between buprenorphine, narcotic analgesic, and centrally acting drugs were studied in prolongation of halothane-induced sleeping and analgesia using the D'Amour-Smith method in mice, and the effect of buprenorphine on monoamine metabolism was studied in rat brain. Diazepam and chlorpromazine prolonged the halothane-induced sleeping time dose-dependently. Buprenorphine (0.01, 0.1, and 1 mg/kg s.c.) inhibited the effect of diazepam, but not that of chlorpromazine. Pentazocine and naloxone also inhibited the effect of diazepam, but morphine did not. It is suggested that the inhibitory effect of buprenorphine on prolongation of halothane-induced sleeping time by diazepam is due to its opiate antagonistic property. Since narcotic antagonists inhibited the effect of diazepam, the endogenous opiate system seems to be involved in this effect. Diazepam or droperidol had no effect on the analgesia of buprenorphine, morphine, and pentazocine. Buprenorphine analgesia was inhibited by reserpine and p-chlorophenylalanine, potentiated by 5-hydroxytryptophan, and not affected by alpha-methyl-p-tyrosine or 3,4-dihydroxyphenylalanine. These results suggest that the serotonergic system plays a modulating role in buprenorphine analgesia. Imipramine and nialamide inhibited buprenorphine analgesia in the test at low stimulus intensity, but potentiated at high stimulus intensity. Buprenorphine (0.1, 1 and 10 mg/kg s.c.) increased the dopamine metabolites, 3,4-dihydroxyphenylacetic acid and homovanillic acid, in various brain areas and the serotonin metabolite, 5-hydroxyindoleacetic acid, in midbrain.

Analgesia↗
PubMed1982

[Analgesic and narcotic antagonist effects of buprenorphine (author's transl)].

Pharmacological properties of buprenorphine were studied in comparison with those of morphine and pentazocine. Buprenorphine was more potent than morphine and pentazocine in analgesic tests, using chemical, thermal, pressure, and electrical stimulation as the nociceptive stimuli. Buprenorphine exhibited analgesic activity in the D' Amour-Smith's test at high stimulus intensity and in the Haffner's test, while pentazocine exhibited little or no analgesic action in these tests. Buprenorphine showed a bell-shaped dose-response curve in the mouse D'Amour-Smith's test at high stimulus intensity. Analgesic action of buprenorphine was antagonized by naloxone administered before buprenorphine, but not antagonized by naloxone administered after buprenorphine. Duration of the analgesic action of buprenorphine was longer than those of morphine and pentazocine. Buprenorphine decreased the amplitudes of evoked potentials which were recorded from the nucleus ventralis posteromedialis, nucleus centralis lateralis, and periaquaductal central gray. As a naloxone antagonist, Buprenorphine was equivalent or less potent than naloxone and more potent than pentazocine. Tolerance developed to the analgesic activity of buprenorphine, but development of tolerance to buprenorphine was less than that of tolerance to morphine. It was concluded that buprenorphine may be a useful analgesic drug because of its high intrinsic activity and long duration of action.

Analgesics↗
PubMed1982

Hemolysis and fusion by influenza viruses with heat-inactivated neuraminidase activity.

Influenza virus hemolytic activity was found to be more heat-resistant than neuraminidase activity, and to be heat-inactivated similarly to hemagglutination activity, in sharp contrast to the case with paramyxoviruses, where the hemolytic activity is the most heat-labile, and hemagglutination and neuraminidase activities are inactivated similarly by heat. Influenza viruses with heat-inactivated neuraminidase activity, which still showed hemagglutination and hemolytic activities, were found to be able to induce cell fusion and envelope fusion. This finding suggested that the hemolytic and fusion activities are not dependent on neuraminidase activity. The hemolytic activity was largely inhibited by anti-hemagglutinin serum of the same subtype. The pH range, heat stability, and antiserum susceptibility of the hemolytic activity were found to be independent of the cells in which the virus was grown.

Allantoin↗
PubMed1981

Free vascularized fibular graft for replacement of the radius after excision of giant cell tumor: case report.

A case is reported in which a giant cell tumor of the distal end of the radius was treated by massive resection and reconstruction with a free vascularized bone graft taken from the fibula. The postoperative course was uneventful. Angiograms made eight weeks after surgery showed patent anastomoses. One year after surgery there was no evidence of recurrence of the tumor, and roentgenograms showed no degenerative changes and bony union with hypertrophy at the junction of the radius and the graft. An excellent clinical result was obtained, and the patient was able to return to his original occupation as an illustrator.

Bone Neoplasms↗
PubMed1981

Effect of ethinyl estradiol on development of mouse fetuses.

Pregnant ICR/JCL mice were given orally 0.02, 0.3, or 2.0 mg/kg body weight/day of ethinyl estradiol in olive oil or vehicle alone on day 11 through day 17 of pregnancy. Pregnant mice of another group received a single oral dose of ethinyl estradiol on day 8 or day 11 of pregnancy. A lethal effect on fetuses of both groups with single and continuous exposure to ethinyl estradiol was observed in a dose-response relationship. Growth suppression of fetuses was only found at term in a dose-response relationship following continuous exposure to ethinyl estradiol. Hypertrophic nipples were seen in 42% of surviving female fetuses prenatally exposed to 2.0 mg/kg of ethinyl estradiol singly on day 11 of gestation. There was not an increase in other congenital malformations in any of the treated groups. These findings indicate that administered ethinyl estradiol can affect the developing mouse embryo but the embryotoxic doses in the mouse are substantially greater than the usual therapeutic or contraceptive doses in the human.

Abnormalities, Drug-Induced↗
PubMed1981

Evidence for the presence of two kinetically distinct active forms of ribonuclease T2. The pH dependence of the steady-state kinetic parameter, kcat, for transphosphorylation of both a natural and a synthetic substrate.

A kinetic study has been made of the RNase-T2-catalyzed transphosphorylation of two adenine nucleotides, adenylyl(3'-5')uridine and adenosine 3'-(1-naphthyl)phosphate. Rates were measured at pH values ranging from 2.6 to 8.2. The observed shape of the plot of log kcat against pH for both the natural and the synthetic substrate suggests that there exist two parallel rate-determining pathways. Two pH-independent rate constants and three ionization constants of the enzyme-substrate complexes were obtained by nonlinear iterative least-squares analysis. Detailed interpretation of the pH profiles was carried out and it is proposed that carboxylate anion is likely to deprotonate O-2' at 4 less than pH less than 6, but at pH greater than 6 an alternative general base would play this role more effectively than the carboxylate group. Another base in its protonated cationic form is responsible for the general acid catalysis.

Binding Sites↗