首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 15 毫秒
1.
2.
It is often assumed that antioxidant nutrients contribute to the protection afforded by fruits, vegetables, and red wine against diseases of aging. However, the effect of fruit, vegetable and red wine consumption on the overall antioxidant status in human is unclear. In this study we investigated the responses in serum total antioxidant capacity following comsumption of strawberries (240 g), spinach (294 g), red wine (300 ml) or vitamin C (1250 mg) in eight elderly women. Total antioxidant capacity was determined using different methods: oxygen radical absorbance capacity (ORAC) assay, Trolox equivalent antioxidant capacity (TEAC) assay and ferric reducing ability (FRAP) assay. The results showed that the total antioxidant capacity of serum determined as ORAC, TEAC and FRAP, using the area under the curve, increased significantly by 7-25% during the 4-h period following consumption of red wine, strawberries, vitamin C or spinach. The total antioxidant capacity of urine determined as ORAC increased (P < 0.05) by 9.6, 27.5, and 44.9% for strawberries, spinach, and vitamin C, respectively, during the 24-h period following these treatments. The plasma vitamin C level after the strawberry drink, and the serum urate level after the strawberry and spinach treatments, also increased significantly. However, the increased vitamin C and urate levels could not fully account for the increased total antioxidant capacity in serum following the consumption of strawberries, spinach or red wine. We conclude that the consumption of strawberries, spinach or red wine, which are rich in antioxidant phenolic compounds, can increase the serum antioxidant capacity in humans. J. Nutr. 2383-2390, 1998  相似文献   

3.
4.
We examined the cross-sectional relation of dietary vitamin C intake to serum lipids in 1,825 preadolescent black and white girls. Dietary vitamin C intake exclusive of supplement use, determined by 3-day diet record, appeared unrelated to total serum cholesterol, high-density lipoprotein-cholesterol, low-density lipoprotein-cholesterol, and triglyceride levels. Because other investigators have demonstrated an inverse association between vitamin C and total serum cholesterol in individuals with elevated total serum cholesterol levels, we analyzed the subgroup of 285 girls (142 blacks and 143 whites) with total serum cholesterol levels > or = 200 mg per dl. Multivariate analyses of this subgroup, which adjusted for saturated fat, polyunsaturated fat, monounsaturated fat, cholesterol, fiber, and energy intake and for body mass index, demonstrated negative association between vitamin C intake and total serum cholesterol. In girls with total serum cholesterol levels > or = 200 mg per dl, each 100 mg per day increase in dietary vitamin C intake (ranges 13-373 and 14-242 mg per day for blacks and whites, respectively) was associated with a total serum cholesterol decrease of 4 mg per dl (95% confidence limits = -10.34, 2.77) in blacks and 13 mg per dl (95% confidence limits = -22.99, -2.68) in whites. If the observed association is causal and generalizable, our results suggest that increased vitamin C intake could play an important role in the cholesterol homeostasis of females with elevated total cholesterol levels.  相似文献   

5.
We used existing data on hepatitis C prevalence, injection-related hepatitis C transmission and needle use in prisons and new data on infectiousness, to estimate the size of study required to detect injection-related hepatitis C in UK prisons. A pilot study of 500 prisoners followed for 10 weeks would have a 65% chance of detecting a hepatitis C seroconversion, conservatively assuming one injection per prisoner per week, and a 3% transmission rate per injection, but uncertainty might persist as to whether transmission had occurred during a short incarceration or before it. If the actual transmission rate was 10%, as recently documented, then such a study would have more adequate statistical power. A definitive study of 3000 prisoners for 10 weeks would expect to detect about six seroconversions, even with conservative estimates of injection frequency and transmission rate. Adequate design and power of these studies is important because of the complacency that could result from false-negative findings. We suggest six risk-factor themes that studies should document.  相似文献   

6.
To investigate pathophysiological diversities in the repairing process of gastric ulcer, distribution density of basic fibroblast growth factor (bFGF)-positive fibroblasts and myofibroblasts and vascular endothelial cells, mucosal haemoglobin content, PAS-positive mucus amount and glandular index were compared in the peripheral region of an open ulcer (the unhealed group; n = 17), the central region of a red scar (the red scar group; n = 32) and the central region of the white scar (white scar group; n = 32). Density of bFGF-positive fibroblasts and myofibroblasts and vascular endothelial cells was highest in the unhealed group, followed by the red scar group, while the white scar group showed a low value close to control. Mucosal haemoglobin content was high in the red scar and unhealed groups. PAS-positive mucus amount in the unhealed and red scar groups showed lower values compared with that in the white scar group. Glandular index in the unhealed group was the lowest, followed by the red scar group, while the white scar group neared control values. Statistically significant correlations were observed between the density of bFGF-positive "fibroblasts and myofibroblasts' and density of bFGF-positive vascular endothelial cells, between the density of bFGF-positive vascular endothelial cells and mucosal haemoglobin content and between the PAS-positive mucus amount and glandular index. Discriminant analysis demonstrated that the unhealed group could be distinguished from the red and white scar groups, based on glandular index, density of bFGF-positive "fibroblasts and myofibroblasts', mucosal haemoglobin content and PAS-positive mucus amount, while the red scar group could be discriminated from the white scar group based on the density of bFGF-positive "fibroblasts and myofibroblasts', density of bFGF-positive vascular endothelial cells, glandular index, haemoglobin content and PAS-positive mucus amount. The white scar group was difficult to discriminate from control. Our present results show that the recovery of glandular formation and mucus production continues throughout the repairing process, whereas the acceleration of angiogenesis and granulation formation is observed only in unhealed ulcers and at the red scar stage.  相似文献   

7.
Red wine polyphenols (RWPPs) were obtained from red wine by absorption and elution from a resin column. Red wine (375 mL/d), white wine (375 mL/d), RWPPs (1 g/d, equivalent to 375 mL red wine/d) in capsules, RWPPs (1 g/d) dissolved in white wine, or a control alcoholic drink (40 g ethanol/d) was given to groups of 6-9 healthy men for 2 wk. Plasma LDL was separated by ultracentrifugation and desalted by dialyzing against a phosphate buffer without EDTA. In the copper-catalyzed peroxidation of LDL (copper-diene assay), the mean lag time increased by 17.8 min after red wine, 14.2 min after RWPP capsules, and 11.7 min after RWPPs in white wine. These groups also showed decreases in thiobarbituric acid-reactive substances, lipid peroxides, and conjugated dienes and increases in plasma and LDL polyphenols. The only change with white wine was an increase in thiobarbituric acid-reactive substances; there were no changes after the control drink. In a second study, RWPPs (1 and 2 g/d) and vitamin E [1000 IU (671 mg)/d] were given for 2 wk. In the copper-diene assay the addition of 10 micromol EDTA/L abolished the increased lag time of 17.7 min seen with 1 g RWPP/d and changed the increased lag time from 13.2 to 4.5 min seen with 2 g RWPP/d. Vitamin E increased lag time by 67.6 min with dialysis without EDTA and by 50.5 min with EDTA. When the column method was used for desalting LDL, all 3 treatments produced an increase in lag time. The failure of some authors to obtain antioxidant effects with the consumption of red wine may be due to the differing techniques.  相似文献   

8.
The red/far-red reversible phytochromes play a central role in regulating the development of plants in relation to their light environment. Studies on the roles of different members of the phytochrome family have mainly focused on light-labile, phytochrome A and light-stable, phytochrome B. Although these two phytochromes often regulate identical responses, they appear to have discrete photosensory functions. Thus, phytochrome A predominantly mediates responses to prolonged far-red light, as well as acting in a non-red/far-red-reversible manner in controlling responses to light pulses. In contrast, phytochrome B mediates responses to prolonged red light and acts photoreversibly under light-pulse conditions. However, it has been reported that rice (Oryza sativa L.) phytochrome A operates in a classical red/far-red reversible fashion following its expression in transgenic tobacco plants. Thus, it was of interest to determine whether transgenic rice phytochrome A could substitute for loss of phytochrome B in phyB mutants of Arabidopsis thaliana (L.) Heynh. We have observed that ectopic expression of rice phytochrome A can correct the reduced sensitivity of phyB hypocotyls to red light and restore their response to end-of-day far-red treatments. The latter is widely regarded as a hallmark of phytochrome B action. However, although transgenic rice phytochrome A can correct other aspects of elongation growth in the phyB mutant it does not restore other responses to end-of-day far-red treatments nor does it restore responses to low red:far-red ratio. Furthermore, transgenic rice phytochrome A does not correct the early-flowering phenotype of phyB seedlings.  相似文献   

9.
An examination of the writings of 19th and early 20th century comparative psychologists such as G. J. Romanes (1883, 1888) and C. L. Morgan (1903, 1923) indicates that they were well aware of many of the issues raised by the recent "cognitivism" in psychology and ethology. A survey completed by 349 Ss in undergraduate ethology classes, an animal behavior conference, and meetings on creationism on attitudes concerning mental continuity between humans and nonhumans showed that emotional continuity was considered more likely than intellectual continuity and that acceptance of evolution favorably disposed Ss to both. Critical anthropomorphism often aids in formulating testable hypotheses, but cognitive approaches to animals are in danger of suffering a fate similar to the earlier comparative mentalism. (88 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   

10.
OBJECTIVE: To quantify the relationship between fruit and vegetable consumption and the incidence of ischaemic heart disease. DESIGN: A meta-analysis of cohort studies of the relationship between ischaemic heart disease and markers of fruit and vegetable consumption, namely dietary intake of fruit, vegetables, carotenoids, vitamin C, fruit fibre and vegetable fibre, and serum concentration of carotenoids and vitamin C, adjusted for other risk factors. MAIN OUTCOME MEASURES: Risk of ischaemic heart disease at the 90th centile of consumption relative to that at the 10th, equivalent to about a four-fold difference in fruit consumption and a doubling of vegetable consumption. RESULTS: The association with ischaemic heart disease was of similar magnitude for all six dietary markers of fruit and vegetable consumption. The median of the six estimates was that risk was 15% (range 12-19%) lower at the 90th centile of consumption than at the 10th. The estimates were generally adjusted for the possible confounding effect of other heart disease risk factors. The serum studies of vitamin C were consistent with this; those of carotenoids suggested a larger difference (43%) but were not adjusted for the important confounding effect of smoking. The substances in fruit and vegetables responsible for the protective effect on heart disease are uncertain but the effect is commensurate with the estimated protective effects of the potassium and folate in fruit and vegetables. Beta-carotene or vitamin E are not likely to be important because randomised trials of these vitamins in large doses have shown no reduction in heart disease mortality. CONCLUSIONS: The risk of ischaemic heart disease is about 15% lower at the 90th than the 1Oth centile of fruit and vegetable consumption.  相似文献   

11.
The prevalence of human immunodeficiency virus (HIV) in male prisoners in South Australia from July 1989 to June 1994 was ascertained from a repeated cross-sectional study. We also compared the criminological and demographic characteristics and histories of drug use of 39 HIV-infected prisoners and a randomly selected sample of 86 uninfected prisoners admitted at the same time. The numbers of HIV-infected prisoners in prison in any month ranged from 4 to 12. Prevalence among the total prison population ranged from 0.4 per cent to 1.4 per cent, and among the subpopulation of injecting drug users from 1.25 per cent to 4.36 per cent. Many HIV-infected prisoners continued after their diagnosis to have lifestyles that resulted in imprisonment. Infected prisoners were significantly older, had spent longer in prison and were more likely to be users of heroin (OR = 13.1) and methadone (OR = 25.4) than controls. Infection with HIV among South Australian prisoners has been continuous since at least the mid-1980s. The recidivism among many of the infected prisoners contributes to the variation in prevalence but also raises concerns about their management. Greater effort to minimise the recidivism of the HIV-infected prisoners could reduce the prevalence of HIV in the prison population.  相似文献   

12.
We showed previously that supplementation for 30 d with 800 IU (727 mg) vitamin E/d did not adversely affect healthy elderly persons. We have now assessed the effects of 4 mo of supplementation with 60, 200, or 800 IU (55, 182, or 727 mg) all-rac-alpha-tocopherol/d on general health, nutrient status, liver enzyme function, thyroid hormone concentrations, creatinine concentrations, serum autoantibodies, killing of Candida albicans by neutrophils, and bleeding time in 88 healthy subjects aged >65 y participating in a double-blind, placebo-controlled trial. No side effects were reported by the subjects. Vitamin E supplementation had no effect on body weight, plasma total proteins, albumin, glucose, plasma lipids or the lipoprotein profile, total bilirubin, alkaline phosphatase, serum aspartate aminotransferase, serum alanine aminotransferase, lactate dehydrogenase, serum urea nitrogen, total red blood cells, white blood cells or white blood cell differential counts, platelet number, bleeding time, hemoglobin, hematocrit, thyroid hormones, or urinary or serum creatinine concentrations. Values from all supplemented groups were within normal ranges for older adults and were not significantly different from values in the placebo group. Vitamin E supplementation had no significant effects on plasma concentrations of other antioxidant vitamins and minerals, glutathione peroxidase, superoxide dismutase, or total homocysteine. There was no significant effect of vitamin E on serum nonspecific immunoglobulin concentrations or anti-DNA and anti-thyroglobulin antibodies. The cytotoxic ability of neutrophils against Candida albicans was not compromised. Thus, 4 mo of supplementation with 60-800 IU vitamin E/d had no adverse effects. These results are relevant for determining risk-to-benefit ratios for vitamin E supplementation.  相似文献   

13.
Vitamin C status and possible associations with the disease process in cystic fibrosis (CF) patients were investigated. Plasma vitamin C concentrations in patients from two different mid-European populations (Swiss, n = 62; Austrian, n = 60) taking no or low-dose vitamin C from multivitamin supplements did not differ from each other or from control subjects (n = 34). Vitamin C concentrations decreased with age (5.05 mumol.L-1, y-1). When followed up for 12 mo, patients had the highest plasma vitamin C concentrations in February and the lowest in May and August (P < 0.01); the decrease in vitamin C was accompanied by increases in plasma malondialdehyde (P < 0.001) and tumor necrosis factor alpha concentrations (P < 0.01). During supplementation with vitamin E for 2 mo or beta-carotene for 12 mo vitamin C concentrations did not change. They correlated inversely with white blood cell count (r = -0.36, P = 0.008), bands (r = -0.36, P = 0.02), alpha 1-acid glycoprotein (r = -0.45, P = 0.002), interleukin 6 (r = -0.46, P = 0.0006), and neutrophil elastase/alpha 1-proteinase inhibitor complexes (r = -0.34, P = 0.02). In patients with vitamin C concentrations < 40 mumol/L, all indexes of inflammation were relatively high, whereas those with concentrations > 80 mumol/L (upper quartile of control subjects) showed clearly lower values. These results are consistent with the hypothesis that by scavenging oxygen free radicals vitamin C interacts with an inflammation-amplifying cycle of activation of alveolar macrophages and neutrophils, release of proinflammatory cytokines and oxygen free radicals, and inactivation of antiproteases.  相似文献   

14.
We investigated the transport pathways available for the uptake of vitamin C in the human placental choriocarcinoma cell line, JAR. These cells were found to possess the capacity to accumulate the vitamin when presented either in the oxidized form (dehydroascorbic acid) or in the reduced form (ascorbate). Dithiothreitol and 5,5'-dithiobis(2-nitrobenzoic acid) were used to maintain vitamin C as ascorbate and dehydroascorbic acid, respectively. The uptake of these two forms of vitamin C in JAR cells was found to occur by different mechanisms. The uptake of the dehydroascorbic acid was Na(+)-independent and was mediated by facilitative glucose transporters as evidenced from the inhibition of the uptake process by glucose. On the other hand, the uptake of ascorbate was Na(+)-dependent and was not sensitive to inhibition by glucose. Substitution of Na+ with other monovalent cations abolished the uptake of ascorbate completely. The uptake process was, however, not influenced by anions. Kinetic analysis indicated the presence of a single saturable transport system for ascorbate with a Michaelis-Menten constant of 22 +/- 1 microM. The dependence of the uptake rare of ascorbate on Na+ concentration exhibited sigmoidal kinetics, suggesting interaction of more than one Na+ ion with the transporter. The Hill coefficient for the Na+ interaction was 2, indicating that the Na(+)-dependent ascorbate transport is electrogenic. The Na(+)-dependent stimulation of ascorbate uptake was primarily due to an increase in the affinity of the transporter for ascorbate in the presence of Na+. It is concluded that the JAR placental trophoblast cell line expresses two different transport systems for vitamin C: one for the reduced form of the vitamin ascorbate; and the other for the oxidized form of the vitamin dehydroascorbic acid.  相似文献   

15.
In 11 patients with alcohol-induced hyperlipemia, of whom 6 showed a Zieve Syndrome increased phospholipids, triglycerides and total cholesterol were found in the red cells stromal. The gasliquid chromatographic analysis of the phospholipid fatty acids showed increased contents of saturated and monounsaturated fatty acids C 16-C 18 smaller contents of longchain highly unsaturated fatty acids. The changes in the fatty acid pattern mainly occurred in patients with Zieve Syndrome and could be important for the mechanism of the hemolytic anemia. Theses findings could be in connexion with vitamin E deficiency.  相似文献   

16.
The recent popularization of self-prescribed large doses of vitamin C has increased the possibility for erroneous conclusions to be drawn from standard clinical methods used in urinary glucose monitoring, due to interference with these methods by the greatly elevated excretion of vitamin C. The coupled-enzyme-chromogen strip tests showed erroneously negative glucose levels in urines of both a diabetic individual and a subject with a genetic low renal threshold for glucose when they were supplementing their normal diets with 1-2 g vitamin C per day. With this regimen, their urinary vitamin C levels reached 200 mg/dl (11.4 mmol/l). For normal urine with vitamin C added, false-positive tests for glucose were found using Benedict's reagent when vitamin C was present at 250 mg/dl (14.3 mmol/l) or higher concentrations. In diabetic individuals consuming large quantities of vitamin C, this interference with standard coupled-enzyme-chromogen strip tests or Benedict's test could present a significant problem in diagnosis and clinical management of the disease. A simple anion exchange method of treating the urine was used to correct the false results.  相似文献   

17.
The presence of resveratrol (3,5,4'-trihydroxystilbene) and its beta-glucoside, piceid (resveratrol-3-beta-D-glucopyranoside), together with their isomers in wine appears to be one of the beneficial factors conferring a protective effect against cardiovascular disease through red wine ingestion. A total of 42 red and white wines was collected in areas from Hokkaido to Kyushu in Japan. The wines were fractionated with a C18 Sep-pak cartridge, and the active principles were eluted with ethyl acetate. Crude trans- and cis-piceid were extracted from a Chinese medicine, 'Kojohkon' (Polygonum cuspidatum), and their retention times and UV absorption were confirmed by HPLC. trans- and cis-Resveratrol, and trans- and cis-piceid were analyzed in a short C18 HPLC column, and cis-resveratrol was quantified from the amount of cis-isomer converted from authentic trans-resveratrol that had been treated by UV irradiation. The content of piceid is shown as the resveratrol equivalent. The average content of total stilbene compounds was 4.37 mg/liter in red wines, while only 0.68 mg/liter in white wines. Red wines made from Pinot noir, Merlot, and Zweigeltrebe grapes all had a high resveratrol content.  相似文献   

18.
Twelve dogs were subjected to cardiopulmonary bypass with membrane oxygenator for 120 minutes. The effect of lipid peroxide injury on red blood cells was studied by measurement of plasma and erythrocyte membrane lipid peroxide, deformabioity of erythrocyte, plasma free hemoglobin, superoxide dismutase, Na(+)-K(+)-ATPase and Ca(2+)-Mg(2+)-ATPase of erythrocytes. The effect of vitamin E on red blood cells was also investigated. The findings indicated that vitamin E might protect red blood cells from lipid peroxide injury during extracorporeal circulation. The mechanism of damage effect of lipid peroxide and the protective effect of vitamin E on red blood cells were briefly discussed.  相似文献   

19.
The current recommended dietary allowance (RDA) for vitamin C, as proposed by the Food and Nutrition Board/National Research Council in 1980 and reconfirmed in 1989, is 60 mg daily for nonsmoking adult males. Levine et al. [Levine, M., Conry-Cantilena, C., Wang, Y., Welch, R. W., Washko, P. W., et al. (1996) Proc. Natl. Acad. Sci. USA 93, 3704-3709], based on a study of vitamin C pharmacokinetics in seven healthy men, have now proposed that the RDA should be increased to 200 mg daily. I have examined, in brief, the experimental and conceptual bases for this new recommendation and its implications for public health and nutrition policy and programs. Using, for illustrative purposes only, data extracted from each of two recent dietary surveys of noninstitutionalized adult males living in households in the Netherlands and the United States, it is predicted that the prevalence of intakes inadequate to meet the individual's own requirement would be about 96% or 84%, respectively, if the criteria of adequacy used for derivation of the 200 mg RDA are accepted. Depending upon the particular average requirement value for ascorbic acid that might be derived from their data, the proposal by Levine et al. would mean a desirable increase in mean intakes in these two populations by as much about 2-to 3-fold. Hence, before an action of this kind is to be recommended, an answer must be sought to the question whether current experimental data including the criteria selected (saturation kinetics) are adequate to establish a new set of requirements for vitamin C, which then carry such profound policy implications. This will require critical assessment of all of the available evidence emerging from laboratory, clinical, and epidemiological studies to determine whether it provides a sufficient rationale for accepting criteria of vitamin C adequacy such as those proposed by Levine et al. and the requirement estimates so derived.  相似文献   

20.
PURPOSE: We tested the role of lipid peroxidation in the demyelination and white matter necrosis associated with radiation injury of the central nervous system. METHODS AND MATERIALS: We irradiated the cervical spinal cords of female F344 rats (23 Gy) and assayed for the accumulation of the peroxidation byproducts malondialdehyde and hydroxyeicosatetraenoic acids, and for the consumption of the endogenous free radical scavengers vitamins E and C. We further tested the role of lipid peroxidation in radiation injury of the central nervous system by determining the sensitivity of the cervical spinal cord to radiation in rats on diets containing deficient, normal, and supplemental levels of the antioxidant vitamin E. Rats were placed on these diets at 4 weeks of age and irradiated (18.5-21.5 Gy) 16 weeks later. RESULTS: During the 5 months between irradiation and the onset of paralysis, no accumulation of peroxidation byproducts or consumption of endogenous scavengers was seen in the cervical spinal cords of the irradiated rats. The cervical spinal cords of some of the rats placed on the diets with deficient, normal, and supplemental levels of vitamin E were analyzed at the time of irradiation and contained 197 +/- 57, 501 +/- 19, and 717 +/- 35 pmol vitamin E/mg protein, respectively. Despite the statistical differences in these levels, the radiation sensitivity of the cervical spinal cord (ED50 for white matter necrosis) in rats receiving the three diets was not different (20.4, 20.7, and 20.6 Gy). CONCLUSION: These data do not support a role for free radical-induced lipid peroxidation in the white matter damage seen in radiation injury of the central nervous system.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号