Protective effect of ascorbic acid against oxidative damage induced by hydrogen peroxide in cultured human peripheral blood lymphocytes

Hydrogen peroxide is one of the reactive oxygen species for cellular injury. It is overproduced during oxidative stress and is known to damage proteins, nucleic acids and cell membranes. The present study was aimed to study the protective effect of ascorbic acid against the toxic doses of hydrogen peroxide using lipid peroxidation and cytokinesis blocked micronucleus assay. Hydrogen peroxide was studied at 50, 100 and 200μM and was found to increase a dose dependent increase in lipid peroxidation and micronuclei frequency. The treatment of 100 and 200μM of hydrogen peroxide separately along with 20, 40 and 80μM of ascorbic acid showed a dose dependent decrease in the lipid peroxidation and micronuclei frequency. The results suggest a protective effect of ascorbic acid against the hydrogen peroxide induced oxidative damage in cultured human peripheral blood lymphocytes.     

Role of ascorbic acid in lead acetate induced lipid peroxidation and hemolysis in human RBC

Lipid peroxidation and hemolysis in humand red blood cells (RBCs) increased on their exposure to increasing concentrations of lead acetate (0.01–1.0mM). However pretreatment of RBCs with ascorbic acid (2mM and 4mM) significantly reduced the effect of lead acetate on lipid peroxidation and hemolysis in human RBCs.     

Reduced plasma ascorbic acid and red cell glutathione contents in sickle cell disease—A preliminary report

Glutathione and ascorbic acid in erythrocytes are suggested to be essential in the detoxification of superoxide radicals and hydrogen peroxide formed during red cell metabolism. In sickle cell patients who are more prone to haemolysis have greater propensity for the formation of superoxide radical and hydrogen peroxide. In the present study conducted on sickle cell patients provide evidence for the presence of reduced levels of both ascorbic acid and glutathione in the red cells. This may seem to suggest that vitamin C supplementation may help such patients who are prone to haemolysis.     

Effect of antioxidants and antibiotics on levels of seminal oxidative stress in leukocytospermic infertile men

Defective sperm function is the most common cause of infertility. A prospective study was carried out to correlate the concentration of nitrite (the stable metabolite of nitric oxide) in seminal plasma with leukocytospermia, and sperm membrane integrity. Total Fifty-seven normozoospermic subjects with and without leukocytospermia visiting the Infertility clinic at KH and MRC, Karad, were included in the present study. Semen samples were checked for sperm concentration, total sperm count, sperm motility, seminal leukocyte concentration and sperm membrane integrity as Hypoosmotic Swelling Test. Similarly the concentration of nitrite in seminal plasma was measured by Griess reaction and total antioxidant power measured as ferric reducing ability of plasma. The concentration of nitrite in seminal plasma was found to be raised with significantly increased leukocyte concentration in semen. Also significantly lowered levels of total antioxidant power along with defective sperm function was observed. Our results suggest that supplementary treatment of antioxidants with antibiotic for leukocytospermic infertile male patients may improve the sperm membrane integrity.     

Interaction between ascorbic acid and gallic acid in a model of fructose-mediated protein glycation and oxidation

BackgroundDietary plant-based foods contain combinations of various bioactive compounds such as phytochemical compounds and vitamins. The combined effect of these vitamins and phytochemicals remains unknown, especially in the prevention of diabetes and its complications. The present study aimed to investigate the combined effect of ascorbic acid and gallic acid on fructose-induced protein glycation and oxidation.ResultsAscorbic acid (15 μg/mL) and gallic acid (0.1 μg/mL) reduced fructose-induced formation of advanced glycation end products (AGEs) in bovine serum albumin (BSA; 10 mg/mL) by 15.06% and 37.83%, respectively. The combination of ascorbic acid and gallic acid demonstrated additive inhibition on the formation of AGEs after 2 weeks of incubation. In addition, synergistic inhibition on the formation of amyloid cross-β structure and protein carbonyl content in fructose-glycated BSA was observed. At the same concentration, the combination of ascorbic acid and gallic acid produced a significant additive effect on the 2,2-diphenyl-1-picrylhydrazyl radical scavenging activity.ConclusionCombining natural compounds such as ascorbic acid and gallic acid seems to be a promising strategy to prevent the formation of AGEs.     

Allosteric process of human glucokinase conducive to fight against diabetes

More than 200 million people worldwide have diabetes. In China alone, about 60 million people are suffering from the disease.Fortunately, scientists are pushing back its boundaries. For instance, a recent study by CAS researchers may shed new light on the treatment of the disease by making cutting-edge progress on studies of the allosteric process of human glucokinase, which has been published by the latest issue of the Proceedings of National Academy of Sciences.     

Role of oxidative stress and antioxidants in aetiopathogenesis and management of oral submucous fibrosis

Lipid peroxidation product, malonaldehyde (MDA) and antioxidants were estimated in plasma and erythrocytes of 34 cases of oral submucous fibrosis (OSMF) of different grades with equal number of healthy controls to evaluate the association of reactive oxygen species (ROS) and OSMF. While plasma MDA was found to be significantly higher in patients (3.3±0.4 nmole/ml, P<0.001) as compared to controls (2.4±0.5 nmole/ml), plasma beta carotene and vitamin E levels were found to be decreased significantly in patients (81.7±14.3 μg/100 ml, P<0.001; 9.3±0.9 mg/L, P<0.01 respectively) with respect to healthy controls (110±20.8 μg/100 ml and 10.1±1.2 mg/L). The decrease in beta-carotene and vitamin E was found to be more significant in OSMF grade II and III than in grade I. After 6 weeks of oral administration of beta-carotene and vitamin E, patients showed increase in plasma level of these two antioxidants along with decrease in MDA level associated with clinical improvement.     

Curative role of pantothenic acid in brain damage of gamma irradiated rats

Radiation induced brain damage is associated with impairment of mitochondrial functions, variations in the level of neurotransmitters, and oxidative stress. Mitochondrial function is closely linked to the level of neurotransmitters since the precursors are supplied by the Kreb’s cycle intermediates. The objective of this study was to evaluate the influence of pantothenic acid, an essential component in the synthesis of Coenzyme A (CoA), on the activity of the Krebs cycle enzymes, isocitrate dehydrogenase (IDH), α-ketoglutarate dehydrogenase (α-KGDH), and succinate dehydrogenase (SDH); the level of aspartic, glutamic and GABA; the activity of transaminases, and oxidative stress, in the cerebrum of γ-irradiated rats. Pantothenic acid (26 mg/Kg) was orally administered to the rats, 2 h after irradiation and during the following 5 days. Animals were sacrificed the 7th day post-irradiation. The exposure of male albino rats to γ-rays (5 Gy) has triggered oxidative stress notified by a significant elevation in the level of malondialdehyde (MDA), an end product of lipid peroxidation, associated to a significant decrease in the content of phospholipids, and the antioxidant compound glutathione (GSH). The activity of IDH, α-KGDH, and SDH, has significantly decreased, while the level of aspartic, glutamic and GABA has significantly increased. In parallel to these changes, the activity of alanine and aspartate transaminase has significantly increased, compared to their values in the control rats. Pantothenic acid treatment, has significantly attenuated oxidative stress; enhanced the activity of IDH, α-KGDH, and SDH; minimized the increase in the level of amino acids and the activity of transaminases, compared to their values in the cerebrum of irradiated rats. In conclusion, pantothenic acid could improve the level of neurotransmitters amino acids, which depends on the enzymatic activities of Krebs cycle and linked to oxidative stress.     

Role of oxidative stress in ethanol induced germ cell apoptosis — An experimental study in rats

The study was undertaken to evaluate the possible involvement of oxidative stress in the pathogenesis of ethanol induced testicular atrophy in rats. Adult male rats were orally administered ethanol at a dose of 1.6 g/kg body weight/day for four weeks. Twenty-four hours after the last treatment the rats were sacrificed using anesthetic ether. Testes were removed and weighed. Apoptosis was studied by using the Feulgen reaction on 5 μ thin paraffin sections of testis. Testicular homogenate was prepared and centrifuged. The supernatant was used for the estimation of extent of lipid peroxidation and antioxidant defense status. There was significant reduction in body weight: and in testicular weight and diameter in ethanol treated rats. Extent of germ cell apoptosis was significantly high in ethanol treated rats. Ethanol treated rats showed significantly high tissue TBARS level and glutathione S-transferase activity; and low tissue ascorbic acid, reduced glutathione, superoxide dismutase, catalase, glutathione peroxidase and glutathione reductase activities. Chronic ethanol administration resulted in high oxidative stress in the testes either due to increased extent of lipid peroxidation or due to decreased antioxidant defenses, and thereby induces germ cell apoptosis leading to testicular atrophy.     

谈虚拟社会角色和职业角色转变

每年数以百万计的大学生走出校园,踏上工作岗位,新时期大学生的就业角色转换问题成为研究和探讨的焦点问题。研究大学生就业角色转换问题,加强针对性的教育和引导,有助于大学生毕业后尽早完成社会职业角色的顺利转换,这对于高校培养顺应社会经济发展合格人才具有重要意义。本文以独特的视角,提出适应计算机与网络信息技术的迅速发展,使用虚拟社会角色积极促进大学生职业角色的转换,为就业后尽快地适应职业生涯打下坚实的基础。     

Evaluation of serum zinc level and plasma SOD activity in senile cataract patients under oxidative stress

An imbalance in the systemic redox status leading to oxidative stress has been an important factor in development of senile cataracts, which is reflected by an increase in serum TBARS and a decrease in plasma SOD activity. Zinc has been an important cofactor required for structural stability of SOD. In the present study the role of serum zinc level and plasma SOD activity was analyzed in senile cataract patients showing significant oxidative stress. Serum TBARS, plasma SOD and serum zinc level was measured in thirty randomly selected senile cataract patients against properly matched controls. Although, the analysis of means showed a significant increase in serum TBARS and decrease in plasma SOD and serum zinc level in cases, but plasma SOD was found to be just significantly correlated (p=0.05) with the serum zinc only in the cases. The results of partial correlation studies and multiple regression analysis, also, showed only a significant correlation and predictable dependence between serum TBARS and plasma SOD, excluding any role of serum zinc level. The present study concludes that it is chiefly the plasma SOD activity, but not the serum zinc level, that determines the proneness of the patients for development of senile cataract.     

金融危机背景下的我国人力资源能力建设

本文从我国人力资源能力建设的现状出发,对金融危机这一非常时期我国人力资源能力建设中存在的问题进行分析,阐述了提高人力资源能力对抵御金融危机的重要意义,并提出相应的解决方案。     

浅谈幼儿园角色游戏的开展

对幼儿来说,游戏是他们的基本生活方式。幼儿通过角色游戏不断地体验着成功与失败,不断地发现自我、认识环境、丰富情感和完善自己的人格．获得身心和谐健康发展。幼儿园以游戏为基本活动．教师对幼儿游戏的指导就显得尤为重要。     

如何发挥周记的作用初探

周记在班级管理中的作用：一是建立师生交流的“绿色通道”,二是实现班级工作的“有的放矢”,三是建立教师的“良师益友”的形象。在现实操作中要解决以下几方面的问题：讲清周记的内容;说明写作的基本要求;尊重学生,认真批阅。     

Role of plasma amino acids and gaba in alcoholic and non-alcoholic fatty liver disease-a pilot study

Alcohol appears to affect brain function, primarily by interfering with the action of gamma-aminobutyric acid (GABA) and other neurotransmitters. As alcohol is mainly metabolized in the liver, therefore we undertook this pilot study to monitor the patterns of changes in plasma amino-acid concentrations due to alcoholic and nonalcohol fatty liver disease and their relation with plasma GABA level. Plasma amino-acid concentrations were measured in 25 alcoholic liver disease (ALD) patients, 18 non-alcoholic fatty liver disease (NAFLD) patients, and 24 age and sex matched control subjects by HPLC. GABA concentration was elevated, while isoleucine and leucine levels reduced significantly in ALD patients compared to the control subjects. Methionine and phenylalanine levels elevated and valine content reduced significantly in ALD patients compared to other two groups, and GABA level was significantly correlated with methionine and phenylalanine. Plasma concentration of lysine was significantly reduced in both groups of liver disease patients compared to the control group, but was not correlated with GABA level. Glycine and tyrosine levels reduced significantly in NAFLD patients compared to other two groups and were significantly correlated with GABA. Interestingly, though amino acids such as alanine, histidine, proline and serine were not affected by liver diseases, but were significantly correlated with GABA level. This pilot study indicated that alcoholic liver disease presented a more deranged plasma amino acid pattern than nonalcoholic, and the amino acid imbalances. More studies are necessary to identify the role of any particular amino acid on brain function and on neurotransmitter(s).     

政府在社会组织评估中作用的思考

社会组织的快速发展使得对社会组织的评估显得日益重要起来。在社会组织评估中政府应该发挥怎样的作用成为各方关注的问题。本文以德国、菲律宾、美国和中国香港的案例分析为基础,根据政府在社会组织评估中参与程度将评估模式分为政府完全参与型、部分参与型、不参与型三种类型,并提出中国评估模式的建立,可能会由政府完全参与型为开始,其他类型逐步普及并完善。