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1.
Chemoprevention represents a new intervention strategy to control some type of carcinogenesis especially in subjects at high risk for cancer development. Experimental and epidemiological data indicate that a variety of nutritional factors including vitamin C and E are effective to lower the risk of some types of cancer. However large prospective studies have failed to find such significant association. A comparative and combined in vitro antimutagenic potential of two antioxidant vitamins ascorbic acid (vitamin C) and α-tocopherol (vitamin E) were evaluated using Ame’s Salmonella typhimurium test assay. Directly acting mutagens such as sodium azide (NaN3) and 4-Nitro-o-phenylenediamine (NPDA), and N-methyl-N′-nitro-N-nitrosoguanidine (MNNG) were used to induce mutation in salmonella strains TA 98 and TA 100. Vitamin C significantly (P < 0.01) and dose dependently inhibited the mutagenicity induced by all the three mutagens. The percent inhibitions of vitamin C at 15 mg/plate were 33.8% (NaN3), 52.5 % (MNNG) and 55.4 % (NPDA). Vitamin E (15 mg/plate) was effective to inhibit mutagenicity induced by NaN3 and MNNG but did not inhibit mutation induced by NPDA. Combination of vitamins (vitamin C plus vitamin E) produced only an additive antimutagenic activity when compared to their activity at 5 mg/plate. The results of the study concluded that vitamin C is a better antimutagenic agent than vitamin E and combination of vitamins did not produce any synergistic activity.  相似文献   

2.
The oxidative modification of lipoprotein especially low density lipoprotein (LDL) plays a key role in the initiation and progression of atherosclerosis. Serum apolipoproteinB (apoB) level is found to be an important marker for atherosclerosis. The present paper focuses on the measurement of serum apoB levels and the effect of Vitamin E, Vitamin C and reduced glutathione on the copper ion induced oxidation of LDL + VLDL (VLDL-Very Low Density Lipoprotein) lipoprotein fraction isolated from the serum of chronic renal failure (CRF) and renal transplanted patients. The level of apoB is significantly higher in the serum of transplanted patients when compared to CRF patients and normal subjects. The level of TBARS formed in oxidized LDL + VLDL lipoprotein fraction of CRF and renal transplanted patients are significantly increased than normal even in the presence of antioxidants but the level of TBARS produced, with antioxidants is comparatively lesser than that produced by oxidized lipoprotein fraction without antioxidants. It may be concluded than that produced by oxidized lipoprotein fraction without antioxidants. It may be concluded that oxidation of LDL can be prevented at an earlier stage by Vitamin E supplementation. The supplementation with Glutathione serves as the best method of preventing the lipoprotein oxidation among the renal diseased patients.  相似文献   

3.
Effect of administration of 600 mg. vitamin E each day, for six days, was observed on activity of some of the anti-oxidant enzymes and levels of malondialdehyde (as an index of free radical mediated damage) in the platelets of patients reperfused after myocardial infarction. It has been found that vitamin E administration significantly lowers the level of malondialdehyde in the patients. Vitamin E administration increases the activities of anti oxidant enzymes (viz. superoxide dismutase, glutathione reductase and catalase) tested both in the patients and healthy controls. Vitamin E administration causes general stimulation of anti-oxidant enzyme activities both in healthy persons and the patients, however, lowering of lipid per-oxidation upon administration of vitamin E is specific for patients. These findings exhibit beneficial role of vitamin E administration in the management of the patients reperfused after myocardial infarction.  相似文献   

4.
Osteoporosis encompasses a wide spectrum of conditions associated with imbalance of osteoclastic and osteoblastic activities. The increased activity of osteoclasts leads to increased free radical formation and hence lipid peroxidation. Present study probes into the role of antioxidants as a palliative treatment for osteoporosis. It involved 50 healthy controls and 75 clinically diagnosed osteoporosis patients. Both the groups underwent baseline assessment of biochemical markers viz. osteoblastic markers: serum Alkaline phosphatase. Free or ionic calcium and Inorganic phosphorus, osteoclastic markers: serum Tartarate resistant acid phosphatase and Malondialdehyde and the antioxidant status: serum Superoxide dismutase and Erythrocyte reduced glutathione. The osteoporotic group was then divided into groups A (Vitamin E-Evinal 400 mg), B (Vitamin C-Celin 500 mg), C (Vitamin E+C-Evinal+Celin) for antioxidant supplementation for a period of 90 days. The results reveal that there is significant fall in concentration of serum MDA (p<0.001), TrACP (p<0.01). Improvement in antioxidant status is reflected by significant rise in concentration of serum SOD (p<0.001) and erythrocyte GSH (p<0.001) after 90 days of antioxidant supplementation in osteoporosis. The findings indicate that on the whole bone status improved with prolonged antioxidant vitamin supplementation, which can be used as a palliative treatment for osteoporosis. The efficacy is not affected whether the vitamins are administered singly or conjointly.  相似文献   

5.
Uric acid an endogenous aqueous antioxidant in normal humans is present in much higher concentrations than vitamin C and has been known to cover 2/3rd of the free radical scavenging capacity in plasma. In the present study average uric acid levels of patients of rheumatoid arthritis were found to be close to the normal individuals. A unique feature was observed after classifying the patients on the basis of the duration of suffering, the patients having longer duration of disease had least uric acid levels as compared to those suffering from relatively lesser period, similar trend was observed in the ascorbic acid estimations. The decline in uric acid values with progression of the disease was much more than what was observed in case of ascorbic acid suggesting the significant role of uric acid in scavenging of free radicals. Too much lowering of Uric Acid should be checked and vitamin C should be supplemented in diet for maintaining the balance between pro oxidant and antioxidant forces to check pro oxidant insult in rheumatoid arthritis.  相似文献   

6.
Folate and cobalamin (Vitamin B12) are two essential micronutrients involved in one-carbon metabolism, which affects heart disease, neural tube defects and cancer. Methylenetetrahydrofolate reductase, the key enzyme involved in one carbon metabolism produces methyl tetrahydrofolate from methylene tetrahydrofolate, which in turn donates methyl group to homocysteine to generate methionine. There exist two common low function polymorphic variants of the methylenetetrahydrofolate reductase gene involving nucleotides 677 C→T and 1298 A→C, which are associated with hyperhomocysteinemia. These polymorphisms are also linked with increased risk for certain cancers such as breast cancer and at the same time providing a protective effect on colorectal cancer. In this case control study, we have evaluated levels of folic acid, vitamin B12 and homocysteine in patients with colorectal cancer. Folate and homocysteine levels did not differ significantly between the two groups; however an increasing trend was noticed with increase in homocysteine levels. Vitamin B12 levels were increased in cases compared to control group.  相似文献   

7.
Alkaptonuria, a metabolic disorder characterized by a triad of homogentisic aciduria, arthritis and ochronosis is one of the first conditions in the charter of group of inborn errors of metabolism proposed to have Mendelian recessive inheritance. It is due to the deficiency of the enzyme homogentisic acid oxidase which catalyzes the conversion of homogentisic acid to maleylacetoacetic acid in the catabolism of tyrosine. Homogentisic acid thus accumulates in cells and body fluids and its oxidized polymers bind to collagen, leading to progressive deposition of grey to bluish black pigment resulting in degenerative changes in cartilage, intervertebral disc and other connective tissues, leading to arthritis which is the only disabling effect in an affected older individual. However the diagnosis can be made in neonates when blackish stain is noticed in an unwashed diaper. Alkaptonuria is treated symptomatically, surgical intervention necessitates in advanced stages, treatment with ascorbic acid (Vitamin C) and dietary restrictions of food containing phenylalanine and tyrosine have proved to be successful in alleviating the symptoms.  相似文献   

8.
Hemodialysis represents a chronic stress status for its recipients. Many hypotheses state that this may be associated with oxidative stress. Thus, there may be deficiency of antioxidants like erythrocytic superoxide dismutase, catalase, vitamin E or increased generation of free radicals like superoxide anions. A study was carried out to investigate oxidant and antioxidant status in chronic renal failure patients undergoing hemodialysis and effect of vitamin E supplementation on these two status. Blood samples were collected from patients before and after hemodialysis and from controls. The samples were analyzed for quantitation of MDA as index of lipid peroxide, nitric oxide, vitamin E, vitamin C and enzymatic antioxidants namely erythrocyte SOD and catalase. As compared to controls, the levels of serum MDA were significantly increased and activities of erythrocyte SOD and catalase, levels of serum nitric oxide, serum vitamin E and plasma vitamin C were significantly decreased both before and after hemodialysis. The efficiency of vitamin E therapy in hemodialysis patients was assessed by re-evaluating oxidant and antioxidant status of same patients after supplementation of vitamin E. Vitamin E supplementation caused decrease in serum MDA and increase in levels of serum nitric oxide, vitamin E, vitamin C and activities of erythrocytic SOD and catalase. Our results suggest the presence of oxidative stress and the possible preventive role of vitamin E therapy in hemodialysis patients.  相似文献   

9.
Folic acid and vitamin B12 are very important vitamins needed for normal cellular metabolic activities. The effects of folic acid and vitamin B12 on liver integrity of growing Wistar albino rats following therapeutic dose of phenytoin administration were investigated. The activities of serum AST, ALT, ALP were investigated. Serum total protein level and lipid profile were also measured as indices of biochemical changes. The ingestion of phenytoin alone in rats significantly reduced serum protein while AST, ALT activities incresed as compared to the control (P<0.05). Supplementation of phenytoin with oral administration of 70microgram/kg body wt of folic acid resulted in a significant reversal in serum total protein and suppression in serum AST and ALT activities. Vitamin B12 supplementation did not afford any significant protection against the effect of phenytoin ingestion but rather phenytoin toxicity was exacerbated in this study. However, the combined effects of vitamin B12 and folic acid ameliorated the effects of phenytoin on serum enzymes of experimental rats. The effect of combination of phenytoin with folic acid or folic acid and vitamin B12 is an interesting finding. Supplementation of phenytoin with folic acid or combination of these vitamins may be recommended for the purpose of ameliorating the adverse biochemical changes which are associated with phenytoin therapy. Further work is ongoing to help elucidate the effects of phenytoin and these vitamins on oxidative stress inducing mechanism.  相似文献   

10.
知识创造到技术创新转换的研究——一个新的视角   总被引：1，自引：0，他引：1  
"场"在知识创造和技术创新之间发挥着重要作用,并且它是促进二者之间转换的一种有效的形式.首先对知识创造到技术创新转化的两种形式进行分析,它们分别是在科学组织或技术组织内以及在科学组织与技术组织之间进行的转化,而后者的转化相对复杂,但是收益却相对更大.不同场的构建与重叠,科技创新高效平台的打造,时于知识创造到技术创新的转换至关重要,它对于巩固我国科技大国乃至建设成为一个科技强国,发挥着极为重要的作用.基于上述理论与实践的重要性,最后提出知识创造到技术创新转换制度的改善主要依靠提高全社会的创新意识,以及通过各种渠道构建有效的资金场、人才场和科技平台.  相似文献   

11.
杨康正 《科教文汇》2012,(22):F0002-F0002,F0003
医院院报作为医院的重要媒介之一,在医院建设发展中发挥越来越重要的作用,它不仅发挥着对职工思想政治教育作用,同时也是传播医院先进文化、加强精神文明建设、构建和谐医院和拓展医疗市场的有效载体。本文试图对院报在医院发展中的功能进行分析和探讨,以更加明确院报生存和发展的意义,促进院报更加健康发展,以发挥院报更加重要的作用。  相似文献   

12.
P-selectin, a cell adhesion molecule is elevated in many inflammatory conditions including preeclampsia which is characterized by generalized endothelial dysfunction and vasoconstriction presumably due to free radicals or mediators released by defective placentation. Vitamin E has been documented to protect cell membranes from oxidative damage and also decrease platelet aggregation. The role of vitamin E in pre-eclampsia is contradictory and hence the study was undertaken. Soluble P-selectin was measured by ELISA and Vitamin-E levels in plasma was estimated spectrofluorometrically. In our study the effect of supplementation of 400 IU/day of Vitamin E (a-tocopheryl acetate) to patients of pre-eclampsia showed significant decreased levels of soluble P-selectin by 2nd week as compared to patients given placebo (P = 0.005). In this short period of study no direct correlations were observed between Vitamin E or P-selectin levels with blood pressure as well as with proteinuria. Future studies may focus on the effect of a-tocopheryl acetate or the phosphate form of Vitamin-E, recently proposed to be the more active form on other inflammatory markers like IL-6, an important stimuli of P-selectin release in pre-eclampsia.  相似文献   

13.
Conclusion  There is considerable epidemiological evidence, which confirms the importance of plasma homocysteine as a powerful predictor of future risk of coronary heart disease and other complications of atherosclerosis. Treatment of hyperhomocysteinemia varies with the underlying cause. However, an inexpensive vitamin supplementation with folic acid, vitamin B12 and vitamin B 6 is generally effective in reducing homocysteine concentrations. Several randomised, controlled trials evaluating the effects of folic acid based supplements on homocysteine concentrations have been conducted over the last decade. In most patients, folic acid alone, and in combination of vitamin B12 and B6, has been shown to reduce homocysteine concentrations within four to six weeks after the initiation of therapy (34). However, no study has yet demonstrated that lowering of homocysteine by vitamin supplementation decreases the cardiovascular morbidity or mortality. Avoidance of excessive meat intake and increased consumption of fresh vegetables and fruits is a dietary measure, which has many health benefits, including a potential to reduce elevated homocysteine levels. The other reasonable approach is to determine levels of fasting homocysteine in high risk patients and it may be advisable to increase their intake of vitamin fortified foods and/or to suggest the daily use of supplemental vitamins. Several large scale randomised trials like Heart Outcomes Prevention Evaluation (HOPE-2) Study, Mcmaster University, Canada, Study of the Effectiveness of Additional Reductions in Cholesterol and Homocysteine (SERCH), Clinical Trial Service Unit, Oxford, U.K, Cambridge Heart Antioxidant Study (CHAOS-2) University of Cambridge, U.K, Bergen Vitamin Study, University of Bergen Norway, Women's Antioxidant and Cardiovascular Disease Study (WACS) Harvard Medical School, U.S.A, Prevention with a combined inhibitor and folate in Coronary Heart Disease (PACIFIC) study, University of Sydney, Australia, and many others are ongoing to assess the effect of homocysteine—lowering by vitamin supplementation on risk of vascular disease.  相似文献   

14.
Fish and fish oils are the richest sources of ω-3 fatty acids. However, they are susceptible to lipid peroxidation due to their high degree of unsaturation. In the present study, the level of thiobarbituric acid reactive material in various fish oils available in the market with and without added Vitamin E was determined. The peroxide levels in fish oil heated to food frying temperature of 180°C and the effect of addition of vitamin E has also been studied. The results indicate that the peroxide levels in almost all the products available in the market were abnormally high irrespective of their Vitamin E content. This might be due to the inefficient methods used for processing and storage of fish oils. Addition of vitamin E was found to have a significant effect in lowering the rate of peroxidation of fish oil during thermal stress, showing that association of antioxidants with ω-3 fatty acids lowers the rate of lipid peroxidation.  相似文献   

15.
刘倩倩 《科教文汇》2012,(13):190-191
高职院校是我国教育系统的重要组成部分,而高职院校的办公室则是重要的管理部门,对于学校正常工作的开展起着极为重要的作用。提升高职院校的办公室工作水平具有极为重要的意义,可以提高高职院校的教学质量以及其他各方面的工作水平。本文着重阐述了高职院校的办公室工作中存在的问题,指出了做好高职院校的办公室工作水平的重要意义并且提出了提升高职院校办公室工作水平的重要措施。  相似文献   

16.
运用扎根理论的方法,考察创业意向向创业行为转化的影响因素与作用机理。研究发现,第一,关键生活事件、情感体验是创业意向向创业行为转化的重要因素;第二,积极情感体验对于创业意向向创业行为的转化起到催化作用;第三,消极情感体验对于创业意向向创业行为的转化起到唤醒作用。  相似文献   

17.
我国在国际上太阳能热水器使用量最大,这对太阳能光热产业的发展有重要的促进作用。文章结合新开发的环保型高效保温太阳能热水器的特点,对太阳能热水器选购、安装、使用、维护的技术性探讨具有较大的社会意义。  相似文献   

18.
费晓红  王建安 《科技通报》2006,22(2):191-195,199
不对称二甲基精氨酸（ADMA）是内源性一氧化氮合酶抑制剂，它抑制血管活性物质NO的合成．导制内皮功能不全，在心血管疾病的发生发展中具有重要作用。大量研究证明，ADMA可能是心血管疾病的一个新的危险因子。  相似文献   

19.
加快发展现代信息服务业的对策研究   总被引：1，自引：1，他引：0  
现代信息服务业是信息产业和现代服务业的重要组成部分.探讨了现代信息服务业在经济发展中的重要作用,分析了现代信息服务业发展面临的问题,提出了加快发展现代信息服务业的对策建议.  相似文献   

20.
论科研团队凝聚力的结构   总被引：13，自引：0，他引：13  
科研团队在现代科学研究中占据越来越重要的地位，团队凝聚力问题 研究也越来越重 要。科研团队的凝聚力是形成科研团队创新力和竞争力的基础。本文着重研究了科研团队凝 聚力的系统结构，指出科研团队凝聚力系统由学术内聚力、文化维持力、人际离散力等三个 子系统构成，并由此提出了增强科研团队凝聚力的对策和措施。  相似文献   

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