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Tomohito Hamazaki

Publications and source records attributed to Tomohito Hamazaki.

27 records · Page 2Linked to original sources
PubMed2004

Suicide attempt and n-3 fatty acid levels in red blood cells: a case control study in China.

BACKGROUND: Epidemiologic studies show that low fish intake is a risk factor of suicidality; however, there are no case-control studies investigating suicide attempt risk and tissue n-3 fatty acid levels. METHODS: We recruited 100 suicide-attempt cases and another 100 control patients injured by accidents who were admitted to three hospitals affiliated with Dalian Medical University in Dalian, China. Case and control subjects were matched for age, gender, and smoking status. Those who were inebriated at the time of hospitalization were excluded. Blood was sampled immediately after admission to a hospital. Washed red blood cells (RBCs) were obtained, and the fatty acid composition of the total RBC phospholipid fraction was analyzed by gas chromatography. RESULTS: Eicosapentaenoic acid (EPA) levels in RBC in the case subjects were significantly lower than those of the control subjects (.74 +/-.52% vs. 1.06 +/-.62%, p <.0001). When the highest and lowest quartiles of EPA in RBC were compared, the odds ratios of suicide attempt was.12 in the highest quartile (95% confidence interval:.04-.36, p for trend =.0001) after adjustment for possible confounding factors CONCLUSIONS: Our findings suggest that low n-3 fatty acid levels in tissues were a risk factor of suicide attempt. Further studies including intervention with fish oil are warranted.

Adult↗
PubMed2004

Dietary n-3 fatty acids selectively attenuate LPS-induced behavioral depression in mice.

Systemic administration of bacterial lipopolysaccharide (LPS) induces a series of physiological and pathological alterations as well as behavioral depression in experimental animals. These alterations induced by LPS administration are known to be mediated by endogenous cytokines and arachidonate metabolites, which may be modulated by dietary n-3 fatty acids. Mice were fed a diet supplemented with n-3 or n-6 fatty acids for 4 weeks prior to LPS administration. Food-motivated behavior after intraperitoneal administration of LPS as compared with that before LPS administration was significantly depressed in the mice fed with the n-6 fatty-acid-rich diet (47% to 85% reduction; P<.05) but not significantly in the mice fed with the n-3 fatty-acid-rich diet. Depression of social exploration by intraperitoneal LPS administration in the n-3 fatty-acid-rich diet group (39% reduction vs. vehicle group) was significantly less in the n-6 fatty-acid-rich diet group (76% reduction vs. vehicle group; P<.05). The behavioral depressions induced by intracerebroventricular LPS injection were not significantly different between the two dietary groups (P=.60). The elevation of serum corticosterone and the hypoglycemic response following intraperitoneal LPS administration were not significantly different between the two dietary groups (P=.57 and P=.43, respectively). We demonstrate that dietary n-3 fatty acids attenuate behavioral depression in mice peripherally administered with LPS without affecting the increase in serum corticosterone and the decrease in serum glucose concentration.

Analysis of Variance↗
PubMed2004

Effect of dietary enrichment with n-3 polyunsaturated fatty acids (PUFA) or n-9 PUFA on arachidonate metabolism in vivo and experimentally induced inflammation in mice.

Mice were fed a diet supplemented with palm oil (control diet), n-3 polyunsaturated fatty acids (PUFA)-, or n-9 PUFA-rich oil for 3 weeks. The n-3 PUFA-rich diet suppressed the generation of both leukotrienes (LT) and prostaglandins (PG), but the n-9 PUFA-rich diet did LT but not PG generation during acute inflammation. Leukocyte accumulation during acute inflammation was not different in the n-3 or n-9 PUFA-rich diet group as compared with the control group. The n-3 PUFA-rich diet but not the n-9 PUFA-rich diet suppressed Freund's adjuvant-induced granuloma formation. The n-9 PUFA-rich diet significantly attenuated galactosamine/lipopolysaccharide-induced liver injury more effectively than the n-3 PUFA-rich diet as compared with the control diet. The present study revealed the differential modification of experimentally induced inflammation in mice by dietary n-3 PUFA and n-9 PUFA, which may be due to their different effects on 5-lipoxygenease and cyclooxygenase metabolism of arachidonic acid during inflammatory processes.

Acute Disease↗
PubMed2003

n-3 long-chain FA decrease serum levels of TG and remnant-like particle-cholesterol in humans.

A large number of papers have reported that administration of n-3 FA reduced serum TG concentrations in hypertriglyceridemic patients. However, few studies have examined the effect of n-3 FA on serum concentrations of remnant-like particle (RLP) cholesterol. Volunteers (n = 41) whose serum TG concentrations were 100-300 mg/dL were recruited and randomly assigned to either an n-3 FA group or a control group with stratification by sex, age, and serum TG level in a double-blind manner. The subjects in the n-3 FA group were administered 125 mL of fermented soybean milk with fish oil containing 600 mg of EPA and 260 mg of DHA/d for 12 wk. The controls consumed control soybean milk with olive oil. Fasting blood samples were obtained before the start of administration and at 4, 8, and 12 wk. EPA concentrations in red blood cells increased significantly in all but one subject in the n-3 FA group, with no significant changes in the control group. TG levels decreased more in the n-3 FA group than in the control group at weeks 4 (P < 0.05), 8 (P < 0.01), and 12 (P < 0.05) with their baseline as covariate. RLP cholesterol levels decreased more in the n-3 FA group than in the control at weeks 8 (P < 0.01) and 12 (P < 0.05) with their baseline as covariate. The groups did not differ in the other lipid levels. It is likely that n-3 long-chain FA may exert anti-atherosclerotic effects by lowering serum TG and RLP-cholesterol levels even at the dose of 860 mg/d.

Adult↗
PubMed2002

The effect of docosahexaenoic acid on aggression in elderly Thai subjects--a placebo-controlled double-blind study.

Docosahexaenoic acid (DHA) administration controls extraggression (aggression against others) in young subjects under psychological stress. However, it is not known whether its administration affects extraggression of elderly subjects. Forty Thai subjects of 50-60 years of age (22 males and 18 females) were recruited from Silpakorn University and nearby villages. They were allocated to the control and DHA groups in a double-blind fashion, and took 10 mixed plant oil capsules and 10 DHA capsules (1.5g DHA/day) for 2 months, respectively. Extraggression was measured with a psychological test (PF Study) at the beginning and end of the study. Just prior to the PF Study at the end of the study, subjects were asked to watch a stressful videotape as a stressor component. The average DHA intake from food was 150-160mg/day. In the group of university employees, extraggression did not change over time with placebo, whereas extraggression significantly decreased (31 +/- 13 to 24 +/- 13%, P = 0.04 by the paired-t test, P = 0.04 by ANOVA). In the group of villagers, there was no significant difference between the control and DHA groups in extraggression. The DHA administration favorably controlled extraggression in at least elderly white-collar workers. The daily intake of 150-160 mg/day of DHA was not enough to control extraggression.

Aggression↗
PubMedDate not supplied

Effects of eicosapentaenoic acids on oxidative stress and plasma fatty acid composition in patients with lupus nephritis.

Eicosapentaenoic acid (EPA) is one of the major components of fish oil, which was reported to have antiatherogenic, anti-inflammatory and immune suppressive effects. In the present study, highly purified EPA was administered to patients with lupus nephritis and the effects of EPA on urinary 8-isoprostane, a reliable marker of oxidative stress, were investigated in these patients. Six outpatients (1 man and 5 women), with lupus nephritis diagnosed by renal biopsy, were entered in the study. We administered 1800 mg EPA ethyl-ester (purity > 95%) daily and examined the urinary 8-isoprostane levels and plasma fatty acid composition before and 3 months after EPA treatment. The urinary 8-isoprostane levels were significantly decreased after the treatment compared with those before the treatment (from 530 +/- 113 pg/mg x Cr to 235 +/- 49 pg/mg x Cr, p = 0.02). The EPA levels in the plasma phospholipid (PL) fraction were significantly increased after the treatment (from 3.30 +/- 0.64 mol% to 8.01 +/- 0.47 mol%, p < 0.001). Arachidonic acid (AA) levels in the plasma PL fraction were significantly decreased after the treatment (from 9.47 +/- 0.28 mol% to 7.33 +/- 0.43 mol%, p < 0.001). The ratios of EPA to AA were significantly increased after the treatment (from 0.35 +/- 0.07 to 1.14 +/- 0.16, p < 0.001). Thus, this preliminary study indicated that EPA might exert beneficial effects on lupus nephritis by decreasing the oxidative stress.

Adult↗
PubMedDate not supplied

The relationship between tissue RBC n-3 fatty acids and pulse wave velocity.

Consumption of n-3 fatty acids is well-known to prevent deaths from coronary heart disease. However, not many studies have investigated the effects of n-3 fatty acids on arteriosclerosis in free living subjects. The pulse wave velocity between the brachia and ankles (baPWV) of 161 healthy male subjects was measured and the fatty acid composition of the total phospholipid fraction of their red blood cells (RBC) analyzed. There was a significant inverse correlation between the eicosapentaenoic acid concentrations in the RBC phospholipid fraction and baPWV of the subjects after adjustment for age, pulse rate and diastolic pressure, or further for body mass index, smoking status, diabetes and the ratio of low-density cholesterol to high-density cholesterol. Although baPWV values may not directly indicate arteriosclerosis, the present study suggests that long-term n-3 fatty acid intake is beneficial for the vascular system.

Adult↗
PubMedDate not supplied

The effect of eicosapentaenoic acid on prostate-specific antigen.

The "Study of EPA Effects on Prostate Cancer" (SEEPC) Group has been conducting a clinical trial with patients who underwent radical prostatectomy. The main purpose of the SEEPC is to evaluate whether eicosapentaenoic acid (EPA) prevents prostate cancer (PC) recurrence. As the surrogate marker of recurrence, the prostate-specific antigen (PSA) level was measured. However, if EPA affects the PSA values independently of PC, PSA may not be a good marker of recurrence in the event of EPA treatment. Thus, in the present study, whether EPA affected the PSA values was investigated using non-PC volunteers. Twenty men, of at least 50 years of age, were recruited, mostly from hospital staff The volunteers were randomly allocated either to the EPA group or the control. The subjects in the EPA group were administered EPA-ethyl ester a dose of 2400 mg/day for 12 weeks, whereas the controls were administered none. Fasting blood samples were obtained before the start of EPA administration and 4 and 12 weeks later. The EPA concentrations in erythrocytes increased in all the subjects in the EPA group (174+/-96%) with no significant changes in the control group (8.5+/-14.0%). There were no significant differences between the two groups in the serum PSA levels, allowing the conclusion that the PSA is an appropriate surrogate marker of recurrence in prostate cancer.

Aged↗