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Biomedical subjects

M Mizuno

Publications and source records attributed to M Mizuno.

At least 505 records · Page 28Linked to original sources
PubMed1988

Effects of medicinal plant extracts from Chinese herbal medicines on the mutagenic activity of benzo[a]pyrene.

The effects of medicinal plants on the mutagenicity of benzo[a]pyrene were studied with Salmonella typhimurium tester strains. The chosen medicinal plants are very frequently used as Chinese herbal medicines. Each medicinal plant was extracted with hot water, which is similar to the method used in Chinese medicinal treatment. Cinnamomi cortex, Rhei rhizoma, Scutellariae radix and Rehmanniae radix were found to decrease the mutagenic activity of benzo[a]pyrene. Atractylodis rhizoma also reduced the mutagenicity of benzo[a]pyrene, but this was not certain, because it showed a killing effect on the cell survival test. Bupleuri radix and Aurantii nobilis pericarpium had an enhancing effect, but then neither of these extracts is itself mutagenic. Each medicinal plant extract showed a different effect on the mutagenicity of benzo[a]pyrene. These effects were classified into 5 types: (I) decreasing effect, (II) killing effect, (III) enhancing effect, (IV) enhancing and decreasing effect and (V) inactive.

Benzo(a)pyrene↗
PubMed1988

Mutagen formed from tryptophan reacted with sodium nitrite in acidic solution.

The reaction products from L-tryptophan treated with nitrite under acidic conditions were investigated for mutagenic activity with the Salmonella typhimurium his reversion assay and for DNA-damaging activity using the rec-assay. The diethyl ether extract of the reaction mixture showed 8 spots on thin-layer chromatography (TLC). One compound from the TLC had high mutagenic activity for TA98 without S9 mix, with little DNA-damaging activity. The mutagen was purified and identified by instrumental analysis as 2-hydroxy-(1-N-nitrosoindole)propionic acid (NIHP). The mutagenic activity of NIHP was determined by the induced mutation frequency method; the induced mutation frequency was about 19.2 X 10(-5) at a dose level of 160 micrograms/plate.

Acids↗
PubMed1988

Comparison of phospholipid synthesis in rat salivary glands: properties of 1-acylglycerophosphorylcholine and 1-acylglycerophosphate acyltransferase systems in microsomes.

1. 1-Acyl-sn-glycerol-3-phosphorylcholine and 1-acyl-sn-glycerol-3-phosphate acyltransferase activities were characterized in rat salivary gland microsomes. 2. The acyl-CoA selectivities between these two kinds of lysophospholipid acyltransferase activities were very different. 3. When the three major glands were compared (parotid, submandibular, sublingual), they showed their own particular acyltransferase activity, but they had very similar in acyl-CoA selectivity. 4. Those observations were also compared in rat liver microsomes.

1-Acylglycerol-3-Phosphate O-Acyltransferase↗
PubMed1988

Clinical effectiveness of a new cervical indwelling catheter in the management of premature rupture of the membranes: a Japanese collaborative study.

The aim of this multiinstitutional study was to evaluate a new cervical indwelling catheter in 84 patients with premature rupture of the membranes at less than 33 weeks' gestation. The average time of insertion of the catheter was 29.1 weeks' gestation, at an average of 2.0 days after rupture, and was left in place for an average of 6.5 days. The mean birth weight was 1417 gm. The mortality rate and the incidence of respiratory distress syndrome were 5.7% and 11.9%, respectively. Amniotic fluid culture was positive in 39.1% of patients before catheter insertion and only 4.3% at the time of delivery. Infection was noted in only four of 84 infants. The incidence of infection was very low in those treated for 3 days or more after catheter insertion.

Adult↗
PubMed1988

Soft X-ray dosimetry and RBE for survival of Chinese hamster V79 cells.

Dosimetry and biological effects of 40 and 50 keV low-energy X-rays generated by a SOFTEX Model CMBW-2 apparatus were studied. Doses were measured using a thin-window parallel-plate ionization chamber; beam quality was assessed using aluminum absorbers; exposure rates per unit current were determined according to the X-ray tube current and exposure times; and thermoluminescent (BeO chip) dosimeters were used to ascertain dose distributions in the irradiation field. The average correction factors for nonuniformity were calculated from the measured dose distributions. The means for ascertaining accurate exposures and doses using these methods are discussed. The dose-survival relationship of Chinese hamster V79 cells were assessed by irradiating them with 40 and 50 kV soft X-rays, 180 kV X-rays, and 60 Co gamma rays. Soft X-rays with three distinct effective energies were tested by changing the tube voltage kV and aluminium filter thicknesses; namely (1) 40 kV without filter, (2) 40 kV with a 0.2 mm thick aluminium filter and (3) 50 kV with a 0.7 mm thick aluminium filter. The effective energies obtained according to attenuation measurements using aluminium for these soft X-rays were 8.1, 11.7 and 18.5 kV, respectively. In this study the relative biological effectiveness (RBE) at 10 per cent survival compared with 60Co gamma rays ranged from 1.5 to 1.6. The RBE of 180 kV X-rays relative to 60Co gamma rays was 1.29. This study provided experimental data for the RBE of V79 cells in the intermediate energy range between hard and ultrasoft X-rays, data for which were previously reported by Goodhead and co-workers (1977, 1979, 1981).

Aluminum↗
PubMed1988

[Anti-ulcer mechanism of mezolidon on water-immersion stress induced gastric ulcers in rats].

To elucidate the anti-ulcer mechanism of mezolidon (KM-1146, 2-(3,4-dimethoxyphenyl)-5-methylthiazolidine-4-one), we investigated gastric mucosal blood flow (laser-Doppler method), transmucosal potential difference, gastroduodenal mucosal surface pH and blood viscosity in rats under a water-immersion stress condition. In the control group, gastric mucosal ulcers occurred three hours after the onset of water-immersion. At that time, gastric mucosal blood flow decreased to 40% and the potential difference decreased to 48%. In the mezolidon-pretreated group, gastric mucosal ulcers were significantly reduced, and the potential difference was significantly higher than in the control group. Gastric mucosal blood flow increased significantly to 120% twenty minutes after the onset of water-immersion and then decreased, but was significantly higher than in the control group. Gastroduodenal mucosal surface pH was not affected by the pretreatment with mezolidon under this condition. Pretreatment with mezolidon did not affect blood viscosity. In conclusion, the anti-ulcer effect of mezolidon may involve the increase and/or maintenance of gastric mucosal blood flow, but more investigations are necessary to understand the mechanism involved.

Animals↗
PubMed1988

Effect of phosphatidyl inositol on progesterone receptors in rat uterine cytosol.

It was reported that unsaturated long chain fatty acids, such as arachidonic acid, oleic acid and docosahexaenoic acid inhibit the binding between progesterone and estrogen receptors and steroid hormones. Most of the long chain fatty acids are contained in phospholipids within the cells. The effect of phospholipids on the binding between R5020 and progesterone receptors was studied. Phosphatidyl ethanolamine and sphingomyelin had no effect on binding, but phosphatidyl inositol and phosphatidyl serine inhibited the binding 53% and 34% respectively. The effect of phosphatidyl inositol on the binding between R5020 and progesterone receptors was dose dependent. Scatchard analysis revealed that the addition of phospholipid markedly decreased the number of binding sites from 1398 fmol/mgp to 258 fmol/mgp, but the dissociation constant was little affected.

Animals↗
PubMed1988

Cyclic changes in epidermal growth factor receptor in human endometrium during menstrual cycle.

Epidermal growth factor (EGF), a potent mitogenic peptide, is known to be present in the fluid of the uterine cavity. Recent studies have demonstrated the messenger RNA for EGF in the rat uterus. Therefore, in an attempt to clarify its physiological role, we investigated the receptors for EGF in human endometrial tissues. The particulate fractions from endometrium possessed the capacity to bind EGF in a specific, saturable and reversible manner. The Scatchard plot was linear, showing a single class of the receptor with an apparent Kd of 3.8 X 10(-9) M. The amount of specific EGF binding was very low during menstruation and increased gradually, reaching its peak in the late follicular phase. There was an abrupt decline in the binding after ovulation with no change in the Kd value. These results imply the possible involvement of EGF in the process of proliferation of human endometrial tissues.

Endometrium↗
PubMed1988

Changes in prolactin levels caused by luteinizing hormone releasing hormone.

The acute effects of luteinizing hormone releasing hormone (LHRH) on the release of prolactin (PRL) were investigated in 12 normal cycling women and 42 women with various menstrual disorders. LHRH (100 micrograms) was bolusly injected intramuscularly and PRL levels were measured immediately before the injection and at 30 minutes and 60 minutes after the injection. LHRH elicited an increase of more than 25% in PRL levels in 15 cases (27.8%) at both 30 minutes and 60 minutes after the injection, whereas PRL levels were decreased by more than 25% in 7 cases (13.0%). The PRL response to LHRH seemed to be related to basal PRL levels. Especially when the PRL concentration was 20 ng/ml or more, LHRH decreased PRL levels in 7 cases out of 16. On the other hand, LHRH increased PRL levels in the majority of cases with a PRL concentration less than 20 ng/ml. In conclusion, the LHRH injection occasionally alters PRL levels in either a positive or negative manner, depending upon the basal PRL levels.

Adolescent↗
PubMed1988

Inhibitory effects of estradiol on glycogen synthesis in primary cell cultures of human endometrium.

The effect of estradiol on glycogen synthesis was examined in a primary cell culture system of the human endometrium. Estradiol inhibited glycogen synthesis in a dose dependent manner with a minimum effective dose of 10(-9)M. Progesterone-induced glycogen synthesis was completely abolished by the simultaneous addition of estradiol. Estradiol did not affect the activity of glycogen phosphorylase in endometrial cells, but the activity of glycogen synthetase was decreased by estradiol irrespective of the presence of progesterone. The inhibitory effect of estradiol on the glycogen synthesis of endometrial cells seemed to be mediated by estradiol receptor, because LY156758, an antiestrogenic drug at receptor site, reversed the inhibitory effect of estradiol.

Adult↗
PubMed1988

Effect of phospholipids on estrogen receptor of rat uterine cytosol.

Phospholipids such as phosphatidyl inositol and phosphatidyl serine inhibit the binding of R5020 and progestin receptors. The effect of phospholipids on the binding of estrogen and estrogen receptors of rat uterine cytosol was studied. Phosphatidyl choline, sphingomyelin, phosphatidyl inositol, phosphatidyl ethanolamine, cardiolipin, and phosphatidic acid inhibited the binding of estradiol and estrogen receptors. This inhibitory effect of phosphatidyl inositol and cardiolipin was dose dependent.

Animals↗
PubMed1988

Inhibitory effect of fatty acids on the binding of androgen receptor and R1881.

Unsaturated long chain fatty acids are known to inhibit the binding between estrogen and estrogen receptor, or progesterone and progesterone receptor in rat uterus. The effects of long chain fatty acids on the binding between androgen receptor of castrated rat prostate and 3H-R1881 were studied. The binding was not affected by saturated fatty acids such as palmitic acid (16:0) or stearic acid (18:0). But unsaturated fatty acids such as oleic acid (18:1), arachidonic acid (20:4) and docosahexaenoic acid (22:6) inhibited the binding between androgen receptor and 3H-R1881. The inhibitory effect of arachidonic acid was dose dependent. Scatchard analysis showed that the addition of arachidonic acid markedly decrease the number of binding sites of androgen receptor. But the dissociation constant was not affected. The inhibitory effect of arachidonic was not a competitive one.

Animals↗
PubMed1988

Effects of ketanserin tartrate on serum lipids in patients with essential hypertension.

Several antihypertensive agents such as thiazide diuretics and some beta-blockers have recently been shown to adversely affect lipid metabolism. Moreover, there is a growing suspicion that the adverse effect on plasma lipids might outweigh the favourable effect of lowering blood pressure. The effect of ketanserin tartrate (20 to 60 mg daily), a new antihypertensive drug, on blood lipids was evaluated in a 12-week non-comparative clinical trial in 34 patients with mild or moderate hypertension. Ketanserin reduced systolic and diastolic blood pressure by 12.2 and 9.8%, respectively, without altering heart rates. Total cholesterol and low density lipoprotein (LDL)-cholesterol levels in the fasting plasma were observed to decrease significantly by 6.3 and 8.8% respectively, whereas mean triglyceride and high density lipoprotein (HDL)-cholesterol remained almost unchanged. These changes were consistent irrespective of their initial values. Significant decrease in apolipoprotein B and E was also observed. Apolipoprotein A-I, A-II, C-II and C-III were not altered significantly. It is speculated that ketanserin affects mainly LDL-cholesterol. Based on these findings, ketanserin is considered to have a potentially beneficial effect on coronary risk profile and should be given full consideration when drug therapy is selected for patients with mild to moderate hypertension.

Adult↗