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Biomedical subjects

T Hamazaki

Publications and source records attributed to T Hamazaki.

At least 91 records · Page 5Linked to original sources
PubMed1988

Comparison of pulse wave velocity of the aorta between inhabitants of fishing and farming villages in Japan.

Pulse wave velocity (PWV) of the aorta was measured in 55 inhabitants of fishing villages and in 49 inhabitants of farming villages, where people normally eat less fish than in the fishing villages. The PWV was significantly slower (indicating less sclerosis) in the fishing villages than in the farming villages (P less than 0.005). This is consistent with a lower incidence of ischemic heart disease in a coastal area, which includes the fishing villages, than in a mountainous area, including the farming villages. It is reported that a long-term fish-diet slows down sclerotic changes of arteries.

Adult↗
PubMed1987

[Trials for simplified hypertonic saline test].

Hypertonic saline test is indispensable for the evaluation of posterior pituitary function. However the test is not simple, including water loading, urine sampling and at least 45 min of hypertonic saline infusion, mostly because the test relies on urinary osmolality as an index of ADH secretion. The object of this study is try to simplify the test by directly measuring plasma ADH concentration before and after 10 min of hypertonic saline infusion. Intravenous infusion of hypertonic saline (5% NaCl, 0.24 ml/kg/min, for 10 min) was performed on normal subjects, patients with diabetes insipidus and patients with renal failure under chronic hemodialysis. Venous blood samples were obtained seriously including just before and after 10 min of the infusion. ADH was extracted from plasma using Sep-Pak C18 column and assayed by specific RIA. Minimum sensitivity of the assay was 0.25 pg/ml. The hypertonic saline infusion resulted in an increase of plasma osmolality by about 8 mOsm/kg H2O and plasma sodium concentration by 4 mEq/l. Plasma ADH increased from 0.77 +/- 0.09 to 3.42 +/- 0.73 pg/ml (m +/- SE, n = 8, p less than 0.01) in normal subjects of ad lib. water drinking and from 0.55 +/- 0.33 to 2.34 +/- 0.33 (m +/- SE, n = 4, p less than 0.05) in water loaded normal subjects (20 ml/kg of water, 60 min before hypertonic saline infusion).(ABSTRACT TRUNCATED AT 250 WORDS)

Diagnosis, Differential↗
PubMed1987

Intake of different eicosapentaenoic acid-containing lipids and fatty acid pattern of plasma lipids in the rats.

The ethyl ester of eicosapentaenoic acid (EPA) is the only pure EPA-containing lipid available in bulk for oral administration. However, there is doubt as to whether EPA ethyl ester can efficiently increase the plasma levels of EPA in comparison with the ability of other kinds of EPA-containing lipids to do so. Therefore, two other kinds of EPA-containing lipids were prepared to study the efficiency of oral administration of those lipids for increasing the EPA content in plasma phospholipids and cholesteryl esters. EPA-containing lipids which were investigated were [A] 1,2,3-trieicosapentaenoyl-glycerol, [B] 2-eicosapentaenoyl-phosphatidylcholine and [C] ethyl ester of EPA. An adjusted amount of lipids [A], [B] and [C] was administered to rats through a gastric tube for 4 days (the first experiment) or for 10 days (the second experiment), and the fatty acid composition of plasma phospholipids and cholesteryl esters was determined. In the first experiment, there were no significant differences in the efficiency for increasing EPA levels in either phospholipids or cholesteryl esters among the lipids. In the second experiment, the EPA levels of both plasma phospholipids and cholesteryl esters of rats administered ethyl ester of EPA were significantly higher than those of rats administered 2-eicosapentaenoyl-phosphatidylcholine. The EPA levels of the rats administered 1,2,3-trieicosapentaenoyl-glycerol were between the levels of the two groups mentioned above, but the differences in the EPA levels were not significant.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1987

Injection of tridocosahexaenoyl-glycerol emulsion and fatty acid composition of blood cells.

An injectable emulsion of docosahexaenoic acid (DHA) was prepared. One hundred ml of the emulsion contained 3 g of 93%-pure 1,2,3-tridocosahexaenoylglycerol (DHA-TG), 1.2 g of 93%-pure 2-docosahexaenoyl-phosphatidylcholine as an emulsifier and 2.5 g of glycerol. Thirty ml of the emulsion of DHA-TG was injected into three rabbits on days 1 and 4 of the study. Blood was taken on day 0, on day 4 just before the second injection and on day 7. The percentage of DHA in the total phospholipid fraction of platelets increased from 0.46% (day 0) to 1.88% (day 4, p less than 0.05) and 3.66% (day 7; p less than 0.02 vs day 0). The percentage of eicosapentaenoic acid (EPA) increased from 0.46% (day 0) to 1.03% (day 4, p less than 0.02) and 1.63% (day 7: p less than 0.05 vs day 0). The percentage of arachidonic acid (AA) decreased from 9.45% (day 0) to 4.31% (day 4, p less than 0.05) and 6.68% (day 7; p less than 0.02 vs day 0). The percentage of DHA in the total phospholipid fraction of erythrocyte membranes increased from 0.23% (day 0) to 0.91% (day 4, p less than 0.05) and 1.52% (day 7; p less than 0.005 vs day 0); that of EPA increased from 0.21% (day 0) to 0.34% (day 4, p less than 0.005%) and 0.52% (day 7, p less than 0.01 vs day 0); that of AA was unchanged. Blood lipids were the same before and after the two injections of the emulsion, except that free fatty acids decreased markedly from 0.32 to 0.06 mEq/1 (p less than 0.02).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1987

Infusion of fish oil emulsion: effects on platelet aggregation and fatty acid composition in phospholipids of plasma, platelets, and red blood cell membranes in rabbits.

An emulsion of fish oil was manufactured to contain 10 g of fish oil/100 mL. Of this, 3 g were eicosapentaenoic acid (EPA) and 1 g was docosahexaenoic acid (DHA). We administered 100 mL of the emulsion into six rabbits intravenously on days 1, 4, 7, 10, and 13. Blood samples were taken on days 0 and 16. The EPA content in phospholipids of plasma, platelets, and red blood cell (RBC) membranes increased 16, 4, and 5 times, respectively. The DHA content in phospholipids of plasma and RBC membranes increased two times whereas that in platelet phospholipids did not increase significantly. Platelet aggregation induced by collagen (10 micrograms/mL) and ADP (5 microM) was depressed significantly after infusion of the fish oil emulsion. In control experiments with soybean oil emulsion, there were almost no significant changes. Therefore, fish oil emulsion may be beneficial to patients who cannot take n-3 fatty acids orally but need them.

Animals↗
PubMed1987

Foreign particles contaminating hemodialyzers and methods of removing them by rinsing.

Foreign particles contaminating hemodialyzers constitute a risk of microembolism and allergic reactions in hemodialysis patients. We investigated the size distribution of particles, and the effects of striking headers of dialyzers and flow rates of rinsing saline on the elimination of foreign particles from dialyzers. Saline used for rinsing was filtered through a Millipore filter, and the particles thus removed were observed microscopically. We also checked changes in particle counts in a closed circuit consisting of a dialyzer and blood lines during 5 h of continuous circulation with a blood pump. The number of contaminating particles increased exponentially as their size decreased. For the sake of reproducibility we counted particles having diameters larger than 3.0 micron to monitor the rinsing efficiency. During rinsing, particles in the dialyzer were effectively eliminated by striking the headers of the dialyzer. We found that striking should be started immediately after the blood line is filled with saline, and that variation in saline flow rates in the range of 350-700 ml/min of saline does not affect the rinsing efficiency. By filtration of saline used for rinsing, particles, mostly ranging from 5 to 200 micron in length, of many shapes and colors were found. Among them were fibers having a length of as much as a few millimeters. Once dialyzers were rinsed effectively, there was almost no change in particle counts in a closed circuit consisting of a dialyzer and blood lines. To rinse dialyzers effectively, at least 1,000 ml of saline are necessary, and striking the headers of dialyzers throughout the rinsing procedure is important.

Equipment Contamination↗
PubMed1986

Infusion of emulsified trieicosapentaenoyl-glycerol into rabbits--the effects on platelet aggregation, polymorphonuclear leukocyte adhesion, and fatty acid composition in plasma and platelet phospholipids.

Using 90%-pure free eicosapentaenoic acid, we synthesized 1,2,3-trieicosapentaenoyl-glycerol (EPA-TG) and manufactured an emulsion of EPA-TG with purified phosphatidylcholine from krill as an emulsifier. After two intravenous injections of the EPA-TG emulsion into rabbits, the EPA content in plasma and platelet phospholipids increased markedly. ADP- and collagen-induced platelet aggregation and polymorphonuclear leukocyte adhesion to glass beads were depressed significantly. No significant changes were observed in serum lipids and liver function. In control experiments which were performed in exactly the same manner except that soybean oil emulsion was used instead of the EPA-TG emulsion, there were almost no significant changes. Our results suggest that an EPA-TG emulsion is applicable to those patients who need both intravenous alimentation and preventive care of thrombosis, such as postoperative patients.

Animals↗
PubMed1986

Inhibition of natural killer cell activity of human lymphocytes by eicosapentaenoic acid.

The effect of eicosapentaenoic acid (EPA) on natural killer (NK) cell activity of human lymphocytes was examined. The addition of an emulsion of trieicosapentaenoyl-glycerol (EPA-TG) emulsified with purified phosphatidylcholine from krill to a cytotoxicity assay system resulted in a marked depression of NK activity. The inhibition was proportional to the concentration of EPA-TG emulsion, and was observed as early as the first one hour of incubation at various effector to target cell ratios. Pretreatment of effector cells with EPA-TG emulsion resulted in significant suppression of their NK activity. Inhibition of cytotoxicity was not due to direct toxicity to effector cells or decreased target cell binding. These results indicate that EPA is a potent inhibitor of NK activity in vitro.

Cells, Cultured↗
PubMed1986

Comparison of the urinary metabolites of prostacyclin and thromboxane of the 2- and 3-series in a Japanese fishing and a Japanese farming village.

We measured PGI2-, PGI3-, and TXA2/3-M (the main urinary metabolites of prostacyclin and thromboxane of the two and three series) in 24-hour urine in a fishing village (21 participants) and a farming village (19 participants) in Japan, expecting to find more PGI3-M in the fishing village than in the farming village. The food consumption for three consecutive days prior to a blood collection was recorded and analyzed for eicosapentaenoic acid (EPA) content. Urine was collected for 24 hours prior to the blood sampling. When our studies were performed (April, 1985), catches of fish were the lowest on record around the fishing village, and the consumption of EPA in the fishing village was less than half of that in the farming village. EPA levels in red cell membrane phospholipids were higher in the fishing village than in the farming village. PGI2-, PGI3-, and TXA2/3-M levels were higher in the farming village than in the fishing village. There was a significant correlation between PGI2- and PGI3-M (r=0.80, n=40) and between PGI3-M and the EPA consumption during the day of urine collection (r=0.52, n=40). We conclude that PGI3 production is probably dependent less on the levels of EPA in tissues estimated by the EPA levels in red cell membranes than on the EPA consumption at the moment.

Adult↗
PubMed1985

The effects on lipids, blood viscosity and platelet aggregation of combined use of niceritrol (Perycit) and a low dose of acetylsalicylic acid.

Forty-six elderly patients (mean age 60 years) suffering from diabetes mellitus (DM), or essential or arteriosclerotic hypertension (HT) were divided into 4 groups. Group 1 served as a control, group 2 was administered 1500 mg niceritrol, group 3 was administered 162 mg acetylsalicylic acid (ASA), and group 4 was administered both 1500 mg niceritrol and 162 mg ASA/day for 8 weeks. Niceritrol lowered serum levels of beta-lipoprotein and total cholesterol and increased HDL cholesterol, usually in 8 weeks. ASA did not affect the lipid-lowering effects of niceritrol. Platelet aggregation induced by epinephrine (1 microgram/ml), collagen (1 microgram/ml), and ADP (2 microM) was depressed in groups 2, 3 and 4. Degrees of depression were higher in groups administered ASA (groups 3 and 4) than in the group administered niceritrol alone (group 2). Plasma fibrinogen levels were lowered in groups administered niceritrol (groups 2 and 4) in 8 weeks. Apparent whole blood viscosity measured at shear rates of 37.6/s and 376/s was improved only in group 4 in 8 weeks, while hematocrit did not change during the study. Because flushing, the most frequent side effect of niceritrol, can be easily controlled by a low dose of ASA, and because the combination of the 2 drugs has some beneficial effects on blood rheology, this combination is considered worthwhile for treatment and prevention of atherosclerosis.

Adult↗
PubMed1984

Effects of fish oil rich in eicosapentaenoic acid on serum lipid in hyperlipidemic hemodialysis patients.

The incidence of atherosclerosis in hemodialysis (HD) patients is very high. Major risk factors are aging, lipid metabolism disturbances, high blood pressure, and smoking. High blood pressure and hypertriglyceridemia, which is atherogenic in the presence of smoking, are encountered very often in HD patients. The effects of eicosapentaenoic acid (EPA) on plasma lipids and blood pressure were studied for the first time in HD patients by the administration of capsules containing fish oil rich in EPA, which is known to lower serum lipid concentration and blood pressure. We treated 12 hyperlipidemic patients (3 of type IIa, 3 of type IIb, and 6 of type IV; 3 males, 9 females; 31 to 70 years of age; 4 to 90 months on HD) with 24 capsules (1.6 g EPA and 1.0 g docosahexaenoic acid) per day for 13 weeks. Serum triglycerides, total cholesterol, and phospholipid decreased significantly after capsule administration. The ratio of EPA to arachidonic acid in serum increased significantly. There was a small but statistically significant decrease in platelet count. Diastolic blood pressure decreased at the end of the experiment. These effects of fish oil are considered favorable for the prevention of atherosclerosis and its subsequent diseases.

Adult↗
PubMed1984

Anxiety among Canadian, Japanese, and American children.

The What I Think and Feel, a revised children's manifest anxiety scale, was administered to 660 children in grades 1 through 6 in the U.S., Japan, and Canada. Both cultural and grade differences were found on the Lie and Anxiety scales. Males did not differ significantly from females on either anxiety or social desirability. Canadian and American children were generally higher on the Lie score (social desirability) and children from the U.S. reported a higher level of anxiety than did children from the other two nations.

Anxiety↗
PubMed1983

Studies on the mechanism of antiaggregatory effect of Moutan Cortex.

The effects of Moutan Cortex and one of its major components, paeonol, on platelet aggregation and arachidonic acid (AA) metabolism in human platelets were studied. One week oral administration of water extract of Moutan Cortex [Moutan Cortex (w), 3 g/day] significantly reduced platelet aggregation and thromboxane B2 (TXB2) formation induced by collagen, epinephrine and ADP. Paeonol dose-dependently inhibited ADP and collagen induced platelet aggregation in vitro. Moutan Cortex (w) and paeonol dose-dependently inhibited the conversion of exogenous [14C]AA to [14C]heptadecatetraenoic acid [( 14C]HHT) and [14C]TXB2 by washed human platelets, while both of them increased its conversion to [14C]12-hydroxy eicosatetraenoic acid [( 14C]12-HETE). High dose of Moutan Cortex (w) inhibited the release of [14C]AA from prelabeled platelets in vitro, while paeonol did not. These results suggest that a reduction in platelet aggregation by the oral administration of Moutan Cortex might be ascribed to a decrease in thromboxane synthesis and that paeonol might play an important role in the antiaggregatory effect of Moutan Cortex because of its potent inhibitory effect on platelet aggregation and thromboxane formation.

Acetophenones↗
PubMed1983

Increase in blood viscosity due to alcohol drinking.

To elucidate the effects of alcohol on thrombotic diseases we focussed on blood rheology which is one of the most important factors of blood flow. We measured the viscosity of whole blood and plasma of 18 healthy volunteers (11 males and 7 females) before and after drinking at a dinner party. There were significant increases in whole blood viscosity (7.4%, P less than 0.005) and plasma viscosity (3.0%, P less than 0.005) after drinking. Judging from the significant correlations between changes in blood viscosity and changes in variables related to hemoconcentration, the ability of alcohol to increase blood viscosity is considered to be due mainly to hemoconcentration. Alcohol itself did not increase whole blood viscosity in vitro at concentrations of 0.1, 0.2, 0.3 and 0.4% (w/v).

Adult↗
PubMed1983

Effect of oral administration of highly purified eicosapentaenoic acid on platelet function, blood viscosity and red cell deformability in healthy human subjects.

Eicosapentaenoic acid (EPA), which is abundant in seafood, has been reported to be a potent antagonist of platelet aggregation and also to reduce the incidene of cardiovascular disorders. We recently reported that EPA also reduces whole blood viscosity. A highly purified EPA, in a soft capsule (75% ethylester form of EPA; EPA-E), manufactured from sardine oil was administered to 8 healthy male subjects for 4 weeks. No side effects were observed. Platelet aggregation and platelet retention significantly decreased. The EPA content in platelet phospholipids markedly increased but docosahexaenoic acid (DHA) and arachidonic acid (AA) contents did not change. A reduction in whole blood viscosity and an increase in erythrocyte deformability were also observed after 4 week's ingestion of EPA-E. The EPA content in erythrocyte membrane phospholipids markedly increased after 4 weeks, and was positively correlated with erythrocyte deformability. Reduction of platelet aggregation and improvement of the rheological properties of the erythrocyte might be explained by an increase in the EPA content in platelet and erythrocyte phospholipids.

Administration, Oral↗