Biomedical subjects

Kei Hamazaki

Publications and source records attributed to Kei Hamazaki.

11 recordsLinked to original sources

PubMed2006

Fish oil reduces tooth loss mainly through its anti-inflammatory effects?

Competing at several steps of arachidonic acid metabolism, n-3 fatty acids reduce production of highly active prostaglandins and leukotrienes and exert anti-inflammatory effects. They are also experimentally shown to be anti-osteoporotic. Periodontitis is responsible for most tooth loss in adult populations. If enough n-3 fatty acids are provided, periodontitis with alveolar bone resorption may be controlled, and tooth loss may be prevented. In fact, n-3 fatty acid administration lowered prostaglandin E(2) production, tooth movement and alveolar bone resorption in animal experiments. Aggression, which may be related with tooth loss, was also controlled with fish oil. Our cross-sectional data supported our hypothesis. We recruited 256 men (22-59 y of age) and 95 women (22-66 y), counted the numbers of their remaining teeth, and analyzed the fatty acid composition of the total phospholipid fraction of RBCs. The beta-coefficient of the numbers of remaining teeth and EPA concentrations in the fraction was 0.89 (per 1% EPA, p=0.007) after adjustment for 9 possible confounding factors. Long-term intervention studies with fish oil planned in the future should be able to test our hypothesis by just adding another very simple endpoint in those studies: tooth loss during the intervention period. This hypothesis may explain the linkage between periodontitis/tooth loss and coronary heart disease.

Adult↗

PubMed2006

Effects of cooking plant oils on recurrent aphthous stomatitis: a randomized, placebo-controlled, double-blind trial.

OBJECTIVE: One-third of the total population seems to develop minor recurrent aphthous stomatitis (RAS) during their lifetime. However, well-controlled dietary intervention studies to prevent minor RAS are very rare. The objective of the present study was to investigate whether the prevalence of RAS decreased with perilla oil (rich in alpha-linolenic acid). METHODS: Thirty subjects (8 men and 22 women) who had minor RAS at least once a month were randomly allocated to a soybean oil group or a perilla oil group in a double-blind manner (experimental phase) after a run-in phase of 4 mo during which subjects used a reference oil, the most popular cooking oil in Japan, or a 50/50 mixture of soybean oil and rapeseed oil. During the experimental phase, subjects were asked to use soybean oil or perilla oil as the sole cooking oil for 8 mo. Blood samples were collected at the start and end of the experimental phase for fatty acid analysis of total plasma phospholipid fraction. Occurrence and needed days for healing of minor RAS were recorded during the two phases and compared. RESULTS: alpha-Linolenic acid concentrations in the plasma phospholipid fraction increased significantly in both groups during the experimental phase to a similar extent. The prevalence of minor RAS in the experimental phase decreased significantly in both groups compared with the run-in phase to a similar extent, without intergroup differences. CONCLUSION: Perilla oil, which is rich in alpha-linolenic acid, was not superior to soybean oil in preventing minor RAS. There was a possibility that avoiding rapeseed oil might be beneficial for prevention of minor RAS.

Adult↗

PubMed2006

The effects of eicosapentaenoic acid-fortified food on inflammatory markers in healthy subjects--A randomized, placebo-controlled, double-blind study.

Epidemiological studies showed that habitual fish intakes were associated with lower blood inflammatory markers. In the present study the effects of a fish oil-containing food on inflammatory markers were investigated in healthy, mostly middle-aged subjects (59 men and 82 women) with normal to mildly elevated triglyceride levels. Study subjects were randomly allocated to two groups in a double-blind manner; one group ingested an eicosapentaenoic acid (EPA)-rich fish oil-fortified drink (0.60 g EPA+0.26 g docosahexaenoic acid/d. EPA group, n=68) for 12 wk. The rest of the subjects took a placebo (control group, n=73). Plasma levels of high sensitivity C-reactive protein (hs-CRP) and soluble tumor necrosis factor-receptors 1 and 2 (sTNF-Rs 1 and 2) were measured at the start and end of intervention. EPA concentrations in the total RBC phospholipid fraction significantly increased by 79% in the EPA group at the end of the study, and they changed very little in the control group (+0.68%). The inflammatory markers did not change in either group. It is likely that fish oil does not change hs-CRP or sTNF-Rs 1 or 2 in subjects without active inflammation.

Adult↗

PubMed2005

The effect of fish oil on physical aggression in schoolchildren--a randomized, double-blind, placebo-controlled trial.

OBJECTIVES: The aim of the study was to investigate whether fish oil supplementation affected Japanese schoolchildren's behavior, with changes in aggression over time as the primary endpoint. DESIGN AND SUBJECTS: A placebo-controlled double-blind study with 166 schoolchildren 9-12 years of age was performed. The subjects of the fish oil group (n=83) took fish oil-fortified foods (bread, sausage and spaghetti). These foods were provided in amounts such that each subject in the fish oil group had an intake of 3600 mg of docosahexaenoic acid+840 mg of eicosapentaenoic acid (EPA)/week for 3 months. The rest (the controls, n=83) took control supplements. At the start and end of the study, psychological tests were performed to assess their aggression. RESULTS: Physical aggression assessed by Hostility-Aggression Questionnaire for Children in girls increased significantly (median: 13 to 15, n=42) in the control group and did not change (13 to 13, n=43) in the fish oil group with a significant intergroup difference (P=.008) with baseline as covariate. The changes in physical aggression scores over time and those of the ratio of EPA/arachidonic acid in RBC (DeltaEPA/AA) were significantly correlated in girls who agreed to blood collection (r=-.53, P=.01, n=23). On the contrary, there were no significant changes in physical aggression in boys. Aggression against others (extraggression) assessed by Picture Frustration Study did not change in the control group (median: 5 to 5) but increased significantly in the fish oil group (4 to 5) with a significant intergroup difference (P=.02) with baseline as covariate. These changes in extraggression might be explained partly by significantly lower baseline values of extraggression in the fish oil group (P=.02) than in the control group. There were no significant correlations between Deltaextraggression and DeltaEPA/AA in blood-sampled children (n=49). Impulsivity of girls assessed by parents/guardians using the diagnostic criteria for attention deficit/hyperactivity disorder of DSM-IV was reduced in the fish oil group (1 to 0) with a significant (P=.008) intergroup difference from the control group (1 to 1). There were no significant correlations between Deltaimpulsivity and DeltaEPA/AA in blood-sampled girls. In males, impulsivity reduced in both groups without any intergroup differences. CONCLUSION: There is a possibility that changes in fatty acid nutrition might affect physical aggression especially in girls.

Aggression↗

PubMed2005

Effect of omega-3 fatty acid-containing phospholipids on blood catecholamine concentrations in healthy volunteers: a randomized, placebo-controlled, double-blind trial.

OBJECTIVE: We previously reported that administration of fish oil rich in docosahexaenoic acid (DHA) increased the plasma ratio of epinephrine to norepinephrine (NE) at rest in young adults who were under chronic stress and that this effect was achieved mainly through depression of NE. However, not many reports have documented the effects of eicosapentaenoic acid (EPA) and DHA on blood catecholamine levels in healthy humans. Therefore, we performed another intervention study to test their effect on catecholamines with healthy subjects under no chronic stress. METHODS: Twenty-one healthy young adults (15 men and 6 women) were randomly assigned to an omega-3 group (n = 9) or a control group (n = 12) in a double-blind manner. Twenty capsules of shellfish-derived lipids containing 762 mg of EPA plus DHA per day were administered to the omega-3 group for 2 mo. The controls took the same amount of placebo capsules. Fasting blood samples after a 30-min rest with a catheter in a forearm vein were obtained at the start and the end of the study for catecholamine measurements. RESULTS: EPA but not DHA concentrations in red blood cells significantly increased in the omega-3 group compared with the control group (P < 0.001). Plasma NE concentrations were significantly decreased in the omega-3 group (from 1.49 +/- 0.39 nmol/L to 1.05 +/- 0.14 nmol/L) compared with the control group (from 1.12 +/- 0.24 nmol/L to 1.39 +/- 0.32 nmol/L) with analysis of covariance (P < 0.001). The differences remained significant (P = 0.01) even after deletion of three subjects in the omega-3 group who had the highest baseline NE values and one in the control group who had the lowest baseline NE value to nullify a significant baseline differences in NE between groups. CONCLUSION: This study demonstrated that EPA plus DHA supplementation lowered plasma NE concentrations in normal volunteers even at the small dose of 762 mg of EPA plus DHA per day. This effect of EPA plus DHA to lower plasma NE concentrations may be important to understand some of the effects of fish oils on diseases.

Adolescent↗

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↗

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↗

PubMed2003

Chronic hepatitis C associated with monoclonal gammopathy of undetermined significance.

BACKGROUND: Two patients were admitted to Mie Prefectural General Medical Center and diagnosed as chronic hepatitis C complicated with monoclonal gammopathy of undetermined significance (MGUS). METHODS: The MGUS class were immunoglobulin (Ig)G. The hepatitis C virus (HCV) RNA genotype was Ib. Based on these findings, they were diagnosed as chronic hepatitis C complicated with MGUS. RESULTS: Histological studies showed chronic hepatitis in the liver and a mild rise in plasma cells without dysplasia and abnormalities in the bone marrow. Serum examination for cryoglobulin was negative. CONCLUSION: Chronic HCV infection might play a pathogenic role in the multistage process leading to lymphoproliferative disorders.

Aged↗

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↗