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Biomedical subjects

S Otani

Publications and source records attributed to S Otani.

At least 271 records · Page 15Linked to original sources
PubMed1990

Effects of Ca2+ ionophore A23187, 1,2-dioctanoylglycerol, and dibutyryl cAMP on the activity and expression of ornithine decarboxylase in guinea pig lymphocytes.

The Ca2+ ionophore A23187 induced small increases in ornithine decarboxylase activity and ornithine decarboxylase mRNA in guinea pig lymphocytes. 1,2-Dioctanoylglycerol potentiated the A23187-induced ornithine decarboxylase activity and the accumulation of mRNA for this enzyme. Dibutyryl cAMP also potentiated the enzyme activity, but had little effect on the accumulation of mRNA. 1,2-Dioctanoylglycerol and 12-O-tetradecanoylphorbol-13-acetate potentiated ornithine decarboxylase activity that had been increased by treatment with both A23187 and dibutyryl cAMP with a consistent increase in the ornithine decarboxylase mRNA. However, dibutyryl cAMP augmented ornithine decarboxylase activity that had been increased by the combination of A23187 and 1,2-dioctanoylglycerol without affecting the ornithine decarboxylase mRNA level. These results suggest that the protein kinase C and cyclic AMP pathways are involved in the enhancement of ornithine decarboxylase activity in guinea pig lymphocytes, but that the mechanisms of the enhancement differ for each pathway, the former increasing the ornithine decarboxylase mRNA level, but not the latter.

Animals↗
PubMed1990

PUVA increases ornithine decarboxylase gene expression in mouse skin.

The influence of topical PUVA on the activity of ornithine decarboxylase (ODC) and its gene expression was investigated in the skin of hairless mouse. After 1 h of application of 0.3% 8-methoxypsoralen, irradiation of 3 J/cm2 of ultraviolet A (UV-A) was administered. The ODC activity markedly increased and peaked at 24 h following UV-A irradiation. The ODC mRNA level, analyzed in dot-blot analysis, elevated to about 5 times that of control at 24 h after treatment. These results show that the PUVA-induced ODC activity is due in part to an increase in ODC gene expression.

Animals↗
PubMed1989

Control by hyperthermia of ornithine decarboxylase in Ehrlich ascites tumor cells.

The effect of hyperthermia on the activity and the messenger RNA levels of ornithine decarboxylase (ODC), which has a rapid rate of turnover in cultured cells, was studied in Ehrlich ascites tumor cells. When the cells were incubated at 42 degrees C, elevation of ODC activity by a change of the medium was prevented. Total RNA was isolated from cells treated at 37 degrees C or 42 degrees C, and the relative abundance of the ODC mRNA was measured by Northern blot analysis. These levels in heat-treated cells were comparable to those in control cells. Inhibition by hyperthermia was reversible. The recovery was suppressed by cycloheximide but not by actinomycin D. In hyperthermic-treated cells, the biological half-life of ODC was 14 min, which was the same time as for cells cultured at 37 degrees C. These results suggest that hyperthermic treatment of Ehrlich ascites tumor cells suppressed ODC induction during translation, not during transcription or after translation.

Animals↗
PubMed1989

Inhibition of protein synthesis in the dentate gyrus, but not the entorhinal cortex, blocks maintenance of long-term potentiation in rats.

We examined whether the critical protein synthesis for maintenance of perforant path long-term potentiation (LTP) takes place in the dentate gyrus or the entorhinal cortex. Field potential recordings were made of responses in the dentate gyrus to stimulation of the perforant path in urethane-anaesthetized rats. Anisomycin (10 micrograms) injected into the dentate gyrus, but not the entorhinal cortex, 1 h prior to tetanization led to nearly complete decay of perforant path LTP of the excitatory postsynaptic potential (EPSP) within 3 h. Intra-dentate injection of neither actinomycin D (a mRNA synthesis inhibitor) nor boiled anisomycin affected LTP maintenance over 6 h. These results suggest that the proteins necessary for the maintenance of LTP over 6 h are synthesized in the dentate gyrus from already existing mRNA without involving protein synthesis in the cell bodies of the afferent fibres.

Action Potentials↗
PubMed1989

Relationship of the effects of interferon on chronic hepatitis B and the induction of 2',5'-oligoadenylate synthetase.

Two years or more after 35 patients (29 men and six women) with chronic hepatitis B were treated by interferon, we studied relationships of age, ALT activity, activity of serum DNA polymerase associated with the hepatitis B virus, serum levels of hepatitis B e antigen and activity of 2',5'-oligoadenylate synthetase in peripheral blood mononuclear cells when treatment started in comparison with treatment results. Seventeen patients were given human lymphoblastoid interferon-alpha; the other 18 patients were given interferon-beta. We measured the activity of 2',5'-oligoadenylate synthetase in these mononuclear cells and found the rate of increase in vivo and in vitro; the correlation between the two was r = 0.68. This enzyme activity in the patients who became negative for DNA polymerase after interferon treatment increased more both in vivo and in vitro than in patients who did not became negative. Also, both the in vivo and in vitro activity increased more in patients who became negative for the e antigen after interferon therapy than in those who remained positive. In the first group, interferon was considered to be effective; in the second, ineffective. Of the patients who became negative, some developed e antibodies and some did not; the increase in this enzyme activity in the two groups was not significantly different. The increase in the activity of 2',5'-oligoadenylate synthetase activity could be used to predict the results of interferon treatment and is an index that can be used before treatment to predict the response.

2',5'-Oligoadenylate Synthetase↗
PubMed1989

Synergistic inhibition of DNA synthesis in Ehrlich ascites tumour cells by a combination of unsaturated fatty acids and hyperthermia.

Wide attention has been given to hyperthermia as a new measure for cancer treatment. Clinical trials of hyperthermia, as they possess antitumour activity on some occasions. When cells were incubated with oleic we examine if fatty acids exert a synergistic effect on Ehrlich ascites tumour cells when combined with hyperthermia, as they possess antitumour activity on some occasions. When cells were incubated with oleic acid and linoleic acid (unsaturated fatty acids) at 37 degrees C, the DNA synthesis of cells was significantly inhibited. Palmitic and stearic acids, which are saturated fatty acids, did not suppress DNA synthesis. Hyperthermic treatment without the presence of fatty acids at 42 degrees C for 1 h decreased DNA synthesis to 62% of the control level of 37 degrees C. The combination of an unsaturated fatty acid and hyperthermia synergistically suppressed DNA synthesis. When the cells were incubated in serum-free medium containing 0.1% albumin, unsaturated fatty acids were more effective in inhibiting DNA synthesis. However, saturated fatty acids had little or no effect on DNA synthesis in control or hyperthermia-treated cells. These results indicate that unsaturated fatty acids are useful for enhancing the inhibitory effect of hyperthermia on DNA synthesis, which may increase the in vitro antitumour effects of hyperthermia.

Animals↗
PubMed1989

Two mechanisms of spermidine/spermine N1-acetyltransferase-induction.

The changes in activity of spermidine/spermine N1-acetyltransferase (SAT), a rate-limiting enzyme in polyamine degradation, were investigated to understand the mechanism of the induction of this enzyme in bovine lymphocytes. The activity of SAT was induced by stimulation with phytohemagglutinin (PHA), calcium ionophore A23187, sodium n-butyrate, or methylglyoxal bis(guanylhydrazone) (MGBG). When the cells were treated with a combination of PHA with either MGBG or butyrate, the increase in SAT was synergistic. However, the treatment of cells with both PHA and A23187 did not cause more induction of the enzyme activity than the stimulatory effects of each agent alone. The elevation in SAT caused by PHA or A23187 was inhibited by the simultaneous addition of 25 microM H-7, a protein kinase C inhibitor; the induction of the enzyme activity by MGBG or butyrate was slightly enhanced in the presence of H-7. In cells treated with a high concentration of O-tetradecanoylphorbol 13-acetate, which results in the breakdown of protein kinase C, PHA and A23187 did not give the maximum response, and MGBG slightly enhanced the enzyme activity. Dibutyryl cyclic AMP inhibited PHA-induced enzyme activity, but it stimulated MGBG- or butyrate-induced activity. Exposure to PHA or A23187 but not to MGBG or butyrate significantly increased the ornithine decarboxylase activity and DNA synthesis. These results showed that there were two different mechanisms of SAT induction. One is dependent on protein kinase C. The other one is independent of protein kinase C and is enhanced by cyclic AMP.

1-Methyl-3-isobutylxanthine↗
PubMed1989

Effect of 1 alpha,25-dihydroxyvitamin D3 on polyamine metabolism in human monocyte cell line-U937.

1. Pretreatment with 1,25-dihydroxyvitamin D3 [1,25-(OH)2D3] caused an increase in ornithine decarboxylase (EC 4.1.1.17) (ODC) activity in lipopolysaccharide (LPS)-stimulated human monocyte cell line, U937. 2. The increase in ODC activity was dose-dependent and preincubation-time dependent. 3. 26,26,26,27,27,27-Hexafluoro-1,25-dihydroxyvitamin D3 was ca 7 times more potent than 1,25-(OH)2D3 in increasing ODC activity. 4. Pretreatment with 1,25-(OH)2D3 also potentiated the activity of spermidine/spermine-N1-acetyltransferase in LPS-stimulated U937 cells. 5. Putrescine levels in cells pretreated with 1,25-(OH)2D3 increased ca 2-fold 4-8 hr after LPS addition. 6. However, pretreatment with 1,25-(OH)2D3 did not cause any increase in ODC mRNA level, suggesting that 1,25-(OH)2D3 may modulate polyamine metabolism at the posttranscriptional level rather than the transcriptional step.

Acetyltransferases↗
PubMed1989

Maintenance of long-term potentiation in rat dentate gyrus requires protein synthesis but not messenger RNA synthesis immediately post-tetanization.

The involvement of new protein and messenger ribonucleic acid synthesis in long-term potentiation was studied in the anaesthetized rat dentate gyrus using several inhibitors of protein synthesis (anisomycin, emetine, cycloheximide and puromycin) and an inhibitor of messenger ribonucleic acid synthesis (actinomycin D). When injected for 1 h just prior to tetanization, the four inhibitors of protein synthesis produced a mild reduction of long-term potentiation of the excitatory postsynaptic potential measured 10 min after tetanization. Anisomycin produced a significantly faster decay of long-term potentiation, while the other inhibitors had more moderate effects. Actinomycin D failed to affect long-term potentiation. In a second experiment, the time-dependency of the anisomycin effect was examined. Anisomycin injected immediately after tetanization promoted decay of long-term potentiation, but when injected after a 15-min delay, the drug had no effect. Inhibition of protein synthesis for 4 h prior to tetanization did not have any more effect on long-term potentiation than inhibition for 1 h. In no experiment was long-term potentiation of the population spike affected by drug manipulation. These results suggest that for long-term potentiation of the excitatory postsynaptic potential to be maintained for at least 3 h proteins must be synthesized from already existing messenger ribonucleic acid, and that this synthesis is mostly completed within 15 min after tetanization.

Animals↗
PubMed1989

[Treatment of gonococcal urethritis with norfloxacin].

Fifty six males with gonococcal urethritis were administered 600 mg of norfloxacin (NFLX) daily for 7 days, before the effects were examined. The pharmaceutical effects were studied on the third and the seventh day after administration. Pronounced effectiveness of 77.8%, effectiveness of 19.4% and ineffectiveness of 2.8% were found on the third day after administration, and pronounced effectiveness of 94.4%, effectiveness of 5.6% and ineffectiveness of 0% were found on the seventh day after administration. Effectiveness of 100% was obtained up to the seventh day. Minimum inhibitory concentration (MIC) of NFLX and ampicillin (AMPC) were determined for 14 strains. The peak of MIC of NFLX was found at 0.05 micrograms/ml and all strains were 0.78 micrograms/ml or lower. The peak of MIC of AMPC was 0.1 microgram/ml. MICs of both drugs were 0.78 micrograms/ml or lower, and resistant bacteria were not found. In view of the analyses of age distribution of patients and source of infection, the peak was found in the twenties and the source of infection in 64.7% were, so-called, professional women.

Adult↗
PubMed1989

[Cerebrospinal fluid findings in 108 Japanese cases of herpes simplex encephalitis].

Cerebrospinal fluid (CSF) findings were evaluated in 108 Japanese cases of herpes simplex encephalitis (HSE). The diagnosis was based on clinical, neurodiagnostic and serological examinations. The maximum abnormal values for opening pressure, red blood cell number, total protein concentration, white blood cell number and percentage of polymorphonuclear cell recorded in each case throughout the course of the illness were distributed widely in the range of 80 to 450 mm CSF, 0 to 20,700/cu mm, 15 to 1,390 mg/dl, 0 to 1,089/cu mm and 0 to 85%, respectively. Xanthochromia was revealed in CSF in 30 out of 101 HSE cases (30%), in 21 of which the xanthochromia was independent of traumatic bleeding during the punctures. The frequency of high density lesion in brain computed X-ray tomography was 43% (9 out of 21) in patients with xanthochromia. On the other hand, it was only 7% (7 out of 71) in patients without xanthochromia. This difference was statistically significant (p less than 0.01). The main cause for xanthochromia was considered to be an escape of red blood cell from the hemorrhagic necrotizing lesion to CSF in 14% of cases, the elevation of protein in CSF in 9% and both in 29%. Red blood cell was revealed in CSF in 24 out of 61 HSE cases (40%). The number of cases with more than 51 red blood cells/cu mm was 5 out of 10 patients with xanthochromia compared with only 8 out of 50 without xanthochromia. This difference was statistically significant (p less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Cerebrospinal Fluid↗
PubMed1989

Effect of acylated derivatives of ascorbate on ornithine decarboxylase induction in Ehrlich ascites tumor cells.

We studied the effects of 6-0-acylated derivatives of ascorbate on ornithine decarboxylase (ODC, E.C.4.1.1.17) activity and the ODC-mRNA level in Ehrlich ascites cells. These derivatives are known to inhibit cell growth. When cells grown to the stationary phase were diluted and stimulated with fresh medium containing 10% dialyzed fetal calf serum, the ODC activity increased rapidly and transiently with a peak at 4 hr. Ascorbate or 2,6-dipalmitoyl ascorbate had little or no effect on the induction of ODC, but 6-0-palmitoyl ascorbate (6P) suppressed the enzyme activity in a time- and dose-dependent way. 6-0-Stearoyl ascorbate had a similar effect. The amount of ODC-mRNA formed after growth stimulation was not affected by 6P. These results indicate that the treatment of Ehrlich ascites tumor cells with 6P caused dose-dependent suppression of ODC induction post-transcriptionally.

Acetylation↗