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Biomedical subjects

N Imaeda

Publications and source records attributed to N Imaeda.

At least 19 recordsLinked to original sources
PubMed2005

Soybean products and reduction of breast cancer risk: a case-control study in Japan.

Components of the Japanese diet, which might contribute to the relatively low breast cancer incidence rates in Japan, have not been clarified in detail. Since soybean products are widely consumed in Japan, a case-control study taking account of the menopausal status was conducted using data from the hospital-based epidemiologic research program at Aichi Cancer Center (HERPACC). In total, 167 breast cancer cases were included and 854 women confirmed as free of cancer were recruited as the control group. Odds ratios (OR) and 95% confidence intervals (95% CI) were determined by multiple logistic regression analysis. There were reductions in risk of breast cancer associated with high intake of soybean products among premenopausal women. Compared with women in the lowest tertile, the adjusted ORs for top tertile intake of tofu (soybean curd) was 0.49 (95% CI, 0.25-0.95). A significant decrease in premenopausal breast cancer risk was also observed for increasing consumption of isoflavones (OR=0.44; 95% CI, 0.22-0.89 for highest vs lowest tertile; P for trend=0.02). The present study found a statistically inverse association between tofu or isoflavone intake and risk of breast cancer in Japanese premenopausal women, while no statistically significant association was evident with the risk among postmenopausal women.

Adult↗
PubMed2002

Discrepancies in dietary intakes and plasma concentrations of fatty acids according to age among Japanese female dietitians.

OBJECTIVE: To clarify the influences of age on dietary intakes and plasma concentrations of fatty acids (FAs) in Japanese female dietitians. SUBJECTS AND METHODS: In autumn 1996, we estimated dietary FA intakes based on 7 day weighed diet records and analyzed plasma FA concentrations in 79 healthy Japanese female dietitians, and investigated their relationships with age, dividing into three age groups (young (32-42 y), middle-aged (43-50 y) and elderly (51-66 y)). RESULTS: Dietary intakes of total FA, saturated FAs, monounsaturated FAs, n-3 polyunsaturated FAs (PUFAs) and alpha-linolenic acid (18:3n-3) were significantly highest in the middle-aged group, and lowest in the elderly. Similar trends were observed for dietary intakes of n-6 PUFAs and linoleic acid (18:2n-6), but there were no differences with regard to eicosapentaenoic acid (EPA; 20:5n-3), docosahexaenoic acid (DHA; 22:6n-3) and n-3 highly unsaturated FAs (HUFAs=EPA+22:5n-3+DHA). On the other hand, plasma concentrations of all FAs except for arachidonic acid (20:4n-6) demonstrated positive correlations with age. Moreover, plasma concentrations of EPA in all age groups, DHA in the elderly and n-3 HUFAs in the middle-aged and the elderly were all positively correlated with dietary intakes. CONCLUSIONS: We should take into account the influence of age on dietary habit and lipid metabolism when interpreting associations between dietary FA intakes and plasma FA concentrations.

Adult↗
PubMed2001

Relative validity of a semi-quantitative food frequency questionnaire versus 28 day weighed diet records in Japanese female dietitians.

OBJECTIVE: To assess the relative validity of a semi-quantitative food frequency questionnaire (SQFFQ) against 28 day weighed diet records (WDRs). SUBJECTS AND METHODS: The SQFFQ was administered to 106 (21 male and 85 female) Japanese dietitians in Aichi Prefecture in autumn, 1996 and four-season consecutive 7 day WDRs were carried out during 1996-1997. We evaluated validity of intakes of 15 foods and 31 macro- and micro-nutrients based on the SQFFQ against those according to 28 day WDRs among 79 Japanese female dietitians. RESULTS: Mean daily intakes of selected foods and nutrients determined by the SQFFQ were generally equivalent to those measured by 28 day WDRs. Pearson's de-attenuated correlation coefficients (CCs) with log-transformation and energy-adjustment between intakes of selected foods and nutrients quantified by the SQFFQ and 28 day WDRs (minimum-median-maximum) ranged from 0.17 (beverages)-0.52 to 0.74 (rice), and Spearman's rank CCs with energy-adjustment ranged from 0.28 (confectionery)-0.42 to 0.68 (rice). Respective Pearson's CCs for intakes of nutrients were 0.28 (PUFAs)-0.51 to 0.73 (magnesium), and Spearman's rank CCs ranged from 0.23 (n-3 PUFAs)-0.45 to 0.71 (magnesium). Favorably higher agreement for intakes of foods/nutrients was achieved along with lower disagreement. CONCLUSIONS: Satisfactorily higher relative validity was attained in Japanese female dietitians with the SQFFQ. This calibrated questionnaire seems therefore appropriate for administration to Japanese dietitians to clarify associations between diet and health/disease. SPONSORSHIP: A grant-in-aid from the Ministry of Education, Science, Sports and Culture (06454242).

Adult↗
PubMed2000

Characterization of lactic acid formation and adenosine triphosphate consumption in calcium-loaded erythrocytes of broiler chickens.

The formation of lactic acid and consumption of adenosine triphosphate (ATP) were measured in erythrocytes from broiler and White Leghorn chickens with the goal of providing further evidence that lactic acid, a metabolite from glycolysis, is an etiological factor for sudden death syndrome (SDS) in broiler chickens. When loaded with Ca2+, erythrocytes exhibited increased lactic acid concentrations. The effect of Ca2+ loading was significantly faster in broiler erythrocytes. In the absence of adenosine used as an energy-yielding substrate, Ca2+ loading was followed by a reduction in ATP concentrations. The effect was also significantly faster in broiler erythrocytes. Intravenous injection of a 20% lactate solution at 0.1 mL/kg produced SDS-like death of broilers but not White Leghorns. The results obtained in erythrocytes indicate that, in broilers, a greater amount of energy is required for regulation of intracellular Ca2+ concentrations, and, thereby, formation of lactic acid is more accelerated. In addition to the result that intravenous lactate injection caused death in broilers, an elevation of lactic acid concentrations in blood, arising from operation of Ca2+ regulation mechanisms, may predispose broilers to incidence of SDS.

Adenosine Triphosphate↗
PubMed2000

Influence of the stocking density and rearing season on incidence of sudden death syndrome in broiler chickens.

Influences of the stocking density and rearing season on the incidence of sudden death syndrome (SDS) were investigated in commercial broiler chickens, which were reared until 63 d after birth. The SDS mortality and total mortality were measured at three different stocking densities of 12, 15, and 18 birds/m2 in rearing seasons of summer, autumn, and winter. At stocking densities of 15 and 12 birds/m2, neither SDS mortality nor total mortality was significantly different throughout the rearing season. However, at 18 birds/m2, SDS mortality significantly increased in summer and winter. The increased SDS mortality was accompanied by a significant increase in total mortality in summer but not in winter. Irrespective of the stocking density, body weight gain and feed intake were lower in summer with no significant change in feed efficiency. The data suggest that stocking density can act as a factor affecting the incidence of SDS in summer and winter, independent of feed efficiency.

Animals↗
PubMed1999

Characterization of serum enzyme activities and electrolyte levels in broiler chickens after death from sudden death syndrome.

Serum activities of lactate dehydrogenase (LDH), glutamic oxaloacetic transaminase (GOT), and creatine phosphokinase (CPK), and serum levels of Na+ and K+ were measured in blood samples from healthy broilers and from broilers suffering from Sudden Death Syndrome (SDS) within 30 min after death. The LDH activity was higher in 4- to 9-wk-old SDS birds than in healthy birds (P < 0.05). The GOT activity was higher in SDS birds irrespective of age (P < 0.05). The CPK activity of SDS birds was not significantly different from that of healthy birds. The K+ level was about twofold higher in SDS birds of 4 to 6 and 7 to 9 wk of age than in healthy birds of the same age, whereas the Na+ level did not differ from that of healthy birds. The LDH, GOT, and CPK activities and Na+ level were unchanged for the post-mortem period of 30 min, but the K+ level increased. These results suggest that an elevations in serum LDH and GOT activities occur in association with SDS, and may be used as a characteristic sign of birds that are dying of SDS.

Aging↗
PubMed1999

Foods contributing to absolute intake and variance in intake of fat, fatty acids and cholesterol in middle-aged Japanese.

On the basis of 351 one-day weighed diet records, we selected foods/recipes contributing to nutrients of interest for a data-based food frequency questionnaire by contribution analysis and multiple regression analysis. Total fat was largely of animal and vegetable origin, irrespective of analytic methods. Saturated fatty acid was mostly from animal and vegetable sources according to contribution analysis, and that of animal origin was the main contributor by multiple regression analysis. Mono-unsaturated fatty acid was substantially supplied by animal and vegetable products by either analytic method. Poly-unsaturated fatty acid, n-6 poly-unsaturated fatty acid and linoleic acid were found to be of vegetable origin and chicken egg according to contribution analysis; while vegetable oil and mayonnaise were the major contributors to variance in intake. Arachidonic acid was, however, mostly provided by animal sources including chicken egg and fish, irrespective of analytic methods. N-3 poly-unsaturated fatty acids and alpha-linolenic acid were of vegetable and marine origin. Eicosapentaenoic and docosahexaenoic acids were particularly from marine products, irrespective of analytic methods, except for chicken egg in docosahexaenoic acid by contribution analysis. Cholesterol was of animal and marine origin by either analytic method. Thus, foods contributing to absolute intake and variance in intake of fat, fatty acids and cholesterol differed considerably.

Animals↗
PubMed1999

Foods contributing to absolute intake and variance in intake of selected vitamins, minerals and dietary fiber in middle-aged Japanese.

Using 351 one-day weighted diet records, we selected foods providing vitamins, minerals and dietary fiber according to contribution analysis (CA) and multiple regression analysis (MRA). Vitamin C was supplied by various vegetables and fruits, and carotene was specifically derived from green-yellow vegetables based on MRA as well as CA. Vitamin A was provided by green-yellow vegetables, fruits, chicken egg and milk (whole) according to CA; whereas chicken liver and pork liver were major sources according to MRA. Vitamin E was mainly of vegetable origin as determined by CA, and largely of spinach, safflower oil and pumpkin as determined by MRA. Vitamin D was mainly derived from chicken egg, fish and mushroom based on CA, and particularly from fish based on MRA. Calcium was supplied by milk (whole), soy products and chicken egg as determined by CA; while milk, tofu and various small fishes were the main contributors to variance. Magnesium was provided by soy products, well-milled rice and spinach according to both analyses, and iron by chicken egg, spinach and soy products. Zinc was largely derived from well-milled rice, followed by chicken egg and milk (whole) as determined by CA, and copper was provided by well-milled rice, soy and wheat products. Dietary fiber was supplied by vegetable sources, whether water soluble or insoluble, based on both analytic methods.

Animals↗
PubMed1998

Development of data-based semi-quantitative food frequency questionnaire for dietary studies in middle-aged Japanese.

BACKGROUND: We designed a data-based semi-quantitative food frequency questionnaire to clarify the relationship between food intake and lifestyle-related diseases among middle-aged Japanese. METHODS: A total of 351 middle-aged individuals were recruited to a one-day weighed diet record survey in 1994. In all, 586 foods were consumed. Intake of 31 nutrients including energy, protein, fat, carbohydrate, vitamins, minerals and dietary fiber by food was computed by multiplying the weight of food consumed by its nutrient content. First, 252 foods with up to 90 cumulative % contribution to nutrient intake were selected. Of these, foods having apparently the same/similar nutrient content were combined into 206 foods by research dietitians. Next, 183 foods with up to 0.90 cumulative multiple regression coefficient and 90 cumulative % contribution were chosen. At this stage an additional food grouping was made. RESULTS: Finally, 102 foods/recipes were included in the questionnaire: rice (2 items), bread and noodles (11), eggs, milk and dairy products (10), soybean, soybean products and other beans (7), meat including beef, pork and chicken (12), fish (5), other fish, shellfish and fish products (10), green-yellow vegetables (8), other vegetables and mushrooms (7), edible roots (2), seaweeds (3), seeds (2), fruits (8), beverages (7) and confectioneries (8). The frequencies were classified into eight categories. Portion size was calculated for the respective foods largely from the one-day weighed diet record. CONCLUSIONS: The developed semi-quantitative food frequency questionnaire substantially covered the intake of 31 nutrients and may be competent to rank middle-aged Japanese efficiently.

Databases as Topic↗
PubMed1994

Preferential uptake of lactosylceramide-bearing dipalmitoylphosphatidylcholine-liposomes into liver: role of membrane fluidity.

The effect of the membrane fluidity of lactosylceramide (LacCer)-bearing liposomes on their liver uptake was investigated in rats. Liposomes consisting of phosphatidylcholine (PC): cholesterol:dicetylphosphate:LacCer (7:2:1:1, molar ratio) were prepared with various fluidities using dipalmitoylphosphatidylcholine (DPPC), dimyristoylphosphatidylcholine (DMPC) and egg PC. These liposomes were all equally stable in serum and were small enough to pass freely through the fenestrae and be taken up easily by liver cells. The LacCer modification of DPPC-liposomes markedly facilitated blood clearance, whereas no enhancing effect of LacCer was observed with egg PC- and DMPC-liposomes. Tissue distribution studies showed the preferential liver uptake of LacCer-bearing DPPC-liposomes, which was largely compatible with the rapid clearance induced by the LacCer modification. In addition, electron spin resonance (ESR) spectroscopic analysis revealed that the LacCer modification of DPPC-liposomes significantly enhanced the order parameter S, indicating that LacCer-bearing DPPC-liposomes were the most rigid of those used in this study. These observations suggest that the membrane fluidity of liposomes in vivo is a crucial factor for their preferential liver uptake.

1,2-Dipalmitoylphosphatidylcholine↗
PubMed1994

The design of oral sustained-release theophylline dosing after conversion from intravenous to oral therapy.

We studied the design of oral sustained-release theophylline dosing after conversion from constant aminophylline infusion. Twelve children with bronchial asthma (9 boys and 3 girls) were evaluated in this study. Each patient received a constant intravenous administration of aminophylline for 4-10 days. Three hours after conversion from constant aminophylline infusion, they received oral sustained-release theophylline twice daily at 12-hour intervals. Blood samples were obtained at least once during the aminophylline infusion, just before conversion from the aminophylline infusion, and 0, 3 and 6 hours, and 4-5 days after administering oral theophylline. Pharmacokinetic parameters were estimated using the serum theophylline concentrations that were obtained during constant aminophylline infusion. These estimates of pharmacokinetic parameters were used to predict the serum theophylline concentrations during oral theophylline therapy. Predicted serum theophylline concentrations using individual pharmacokinetic parameters were fitted with actual measured values in this study. When switching a patient from intravenous aminophylline to sustained-release oral theophylline, the use of Bayesian analysis of serum theophylline concentration values obtained during intravenous therapy works well in predicting serum theophylline concentrations and in determining oral dosages that maximize the drug's effectiveness.

Administration, Oral↗
PubMed1994

Prediction of steady-state serum theophylline concentration in children by first-order and zero-order absorption models.

We estimated the pharmacokinetic characteristics of theophylline in children with bronchial asthma after multiple oral dosing of Theo-Dur, in order to determine whether the absorption of the drug is best described by a zero-order absorption kinetic model (0-order model) or a first-order absorption kinetic model (1-order model). Thirteen children with bronchial asthma were evaluated in this study. Each patient received Theo-Dur twice daily at 12-hour intervals. Blood samples were taken at 0, 3, 6, 9 and 12 hours after the administration; plasma theophylline concentration was determined by the fluorescence polarization immuno assay method. Pharmacokinetic parameters for each patient were estimated by a one-compartment open model with 0-order or 1-order absorption and 1-order elimination rate constants. The regression curve predicted using the 0-order model fitted well to the observed value. In contrast, the use of the 1-order model was overestimated considerably in the absorption phase the precision of the prediction using the 0-order model was better than the use of the 1-order model. This study suggests that the 0-order model gave better estimated pharmacokinetic parameters when applied to Theo-Dur than did the 1-order model in children.

Adolescent↗
PubMed1989

Age-related change in tissue-to-plasma partition coefficient of cefazolin for noneliminating organs in the rat.

Age-related changes in tissue distribution characteristics of cefazolin, a cephalosporin antibiotic, were examined for noneliminating organs of rats. The in vivo tissue-to-plasma partition coefficients (Kp,vivo) varied markedly among different ages and organs. In particular, muscle and skin acted as reservoirs for cefazolin distribution. There were also marked differences in interstitial fluid space (IS), determined using [14C]inulin, among different ages and organs. For muscle and bone, the magnitude of the age-related changes in Kp,vivo of cefazolin and IS was in the order of 1-week-old greater than 7-week-old = 100-week-old greater than 50-week-old rats. This is well correlated with the age-related changes in the volume of distribution at the steady state of cefazolin per body weight (Vdss/BW) and the extracellular fluid volume per body weight (Vecw/BW) determined previously using [14C]inulin. The predicted Kp value (Kp,pred) was estimated by incorporating the serum protein binding parameters of cefazolin, the IS values, and an interstitial-to-plasma albumin concentration ratio (AR) into equations derived from an extracellular fluid model. The Kp,pred values exhibited a fairly good correspondence with the Kp,vivo values determined for various organs, except gut, in rats of all four ages. These results suggest that the determinant of the age-related change in Vdss/BW is the difference in the IS value of muscle and bone, while the age-related change in serum protein binding plays only a modest role.

Adolescent↗
PubMed1988

Prediction of steady-state plasma theophylline concentration by Bayesian algorithm.

The use of Bayesian algorithm on theophylline pharmacokinetics was studied in asthmatic patients. Each patient received multiple oral doses of the sustained-release theophylline tablet formulation, Theo-Dur, in an amount of 200-400 mg as maintenance dose. Plasma theophylline concentration was measured by a commercially available substrate-labeled fluorescent immunoassay. The data were analyzed by applying a one-compartment model with both zero-order and first-order absorptions based on a nonlinear least squares method, Bayesian algorithm. The present study indicated that the zero-order absorption model provided better estimated pharmacokinetic parameters than the first-order absorption model. It was also found that prediction by the Bayesian method is dependent on number of sampling trials, but the best sampling time is still unknown. This may be due to the small peak-trough plasma concentration differences. From these findings, we suggest that parameters with larger variances should be chosen by considering the interindividual and intraindividual variabilities in order to improve the accuracy of population pharmacokinetics.

Absorption↗
PubMed1987

Absorption of theophylline from a sustained-release theophylline tablet formulation, Theo-Dur.

The absorption kinetics of theophylline after single oral administration of a sustained-release theophylline tablet formulation, Theo-Dur, were studied in healthy volunteers. The pharmacokinetic parameters were estimated by utilizing a one-compartment model with zero-order or first-order absorption according to the procedure "Praxis". The release of theophylline from the formulation in the in vitro dissolution study was shown to be an apparent zero-order process. The in vivo studies demonstrated that the time required to reach maximum plasma concentration of theophylline was about 8 h. The mean residence time in vivo, MRT, was 18.6 h. The present study also showed that the formulation was good sustained-release properties with adequate bioavailability and that the in vitro sustained-release characteristic was confirmed to be reflected in the plasma concentration-time profile of theophylline in the in vivo. The computer-predicted concentrations of theophylline based on the zero-order absorption model fitted to the observed data points better than those based on the first-order absorption model. The regression curves obtained by nonlinear least squares method based on the first-order absorption model underestimate the maximum observed plasma concentrations of theophylline. There was a highly significant relationship between observed and calculated around the maximum plasma concentration data based on the zero-order absorption model. These results show that the drug absorption from the formulation is best described by an apparent zero-order rather than a first-order absorption model.

Absorption↗