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排序方式: 共有66条查询结果,搜索用时 15 毫秒
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Saadet Gümüşlü Süreyya Bi˙lmen Dijle Ki˙pmen Korgun Piraye Yargiçoğlu Aysel Ağar 《Free radical research》2013,47(6):621-627
Antioxidant defenses within the lung are pivotal in preventing damage from oxidative toxicants. There have also been several reports with conflicting results on the antioxidant system during aging. In this study, we attempted to investigate age-related alterations in both antioxidant enzyme activities and thiobarbituric acid-reactive substances (TBARS), a product of lipid peroxidation, in the whole lung of control and sulfur dioxide (SO2) exposed rats of different age groups (3-, 12-, and 24-months-old). Swiss-Albino Male rats were exposed to 10 ppm SO2 1 hr/day, 7 days/week for 6 weeks. The antioxidant enzymes examined include Cu,Zn-superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GSH-Px) and glutathione S-transferase (GST). A mixed pattern of age-associated alterations in antioxidant activities was observed. SOD, GSH-Px and GST activities were increased with age, but CAT activity was decreased. Lung SOD, GSH-Px and GST activities were also increased in response to SO2. The level of TBARS was increased with age. SO2 exposure stimulated lipid peroxide formation in the lung as indicated by an increase in the level of TBARS. These findings suggest that both aging and SO2 exposure may impose an oxidative stress to the body. We conclude that the increase in the activities of the antioxidant enzymes of the lung during aging, could be interpreted as a positive feedback mechanism in response to rising lipid peroxidation. 相似文献
3.
Abdulkadir Kucukbayrak Saadet Cakmak Ismail Necati Hakyemez Tekin Tas Hayrettin Akdeniz 《Folia microbiologica》2013,58(4):343-347
Since the 1990s, blood donors have been scanned for anti-hepatitis C virus (anti-HCV) antibodies, which can be defined by enzyme immunoassay as a screening test. In this population, false-reactive ratios have been high. Recently, some authors have aimed to find a cutoff value for anti-HCV different from those established by test manufacturers to predict HCV infection. In this study, 321 patients, after two repeating tests, had reactive results in s/co <10 titers on anti-HCV test. The patients were 29.6 % (n?=?95) in women and 70.4 % (n?=?226) in men. The patients were classified into three groups by Western blot (WB) results (PS, positive; NG, negative; and ID, indeterminate). The average anti-HCV titer of the whole group was 2.61?±?1.96. Anti-HCV titers of subgroups were 2.43?±?1.95 in NG, 4.93?±?2.53 in PS, and 2.50?±?1.65 in ID (p?<?0.001). There was a significant difference between NG and PS and between PS and ID subgroups (p?<?0.001). There was a positive correlation between WB and anti-HCV titers in all patients (r?=?0.298, p?<?0.001), in women (r?=?0.282, p?<?0.001), and in men (r?=?0.337, p?=?0.002). According to receiver operator characteristic curve analysis, the cutoff value of anti-HCV titer to predict hepatitis C infection was >2.61 s/co, with 74.1 % sensitivity and 71.6 % specificity (area under the curve, 0.820; 95 % confidence interval, 0.753 to 0.887). We suggest that an effective cutoff value for anti-HCV other than that established by the manufacturer cannot be assigned to predict hepatitis C infection for blood donors in low-prevalence areas. 相似文献
4.
Hacer Esen Saadet Alpdağtaş Mehmet Mervan Çakar 《Preparative biochemistry & biotechnology》2019,49(5):529-534
AbstractSeveral protein expression systems can be used to get enzymes in required quantities and study their functions. Incorporating a polyhistidine tag is a beneficial way of getting various enzymes such as FDHs for industrial applications. The NAD+ dependent formate dehydrogenase from Chaetomium thermophilum (CtFDH) can be utilized for interconversion of formate to carbon dioxide coupled with the conversion of NAD+ to NADH. In this study, N-terminal His tagged CtFDH (N-CtFDH) and C-terminal His tagged CtFDH (C-CtFDH) was constructed to learn the effect of His tag location on the activity and kinetic parameters of the enzyme. The solubility of proteins was not affected by tag position, however, an interference on the N-terminal region caused a deterioration in specific activity and the kinetic ability of enzyme. The obtained results indicated that the C-terminus of the enzyme is an appropriate region for tag engineering. The C-CtFDH has an approximately three-fold larger specific activity and two-fold higher catalytic efficiency than N-CtFDH. The results suggest that insertion of a His-tag at the N-terminal or C-terminal end of CtFDH has different effects on the protein and the N-terminal fragment of the protein is crucial for the function of CtFDH. 相似文献
5.
The aim of the present study is to evaluate the oxidative effects of lead with increased concentrations by the determination
of antioxidant enzyme activities (superoxide dismutase (SOD), catalase (CAT), glutathione reductase (GR), and ascorbate peroxidase
(AP)) and lipid peroxidation levels in the stem and leaves of watercress (Nasturtium officinale R. Br.) which was exposed to lead acetate, Pb (CH3COOH)2 regime with concentrations of 0, 50, 100, 200, 250, and 500 mg/L Pb in a hydroponic culture. After 14 days, accumulation
of lipid peroxidation in stems and leaves and changes in activity of antioxidant enzymes were determined spectrophotometrically.
The maximum accumulation was observed in the highest concentration group. In this group, lipid peroxidation levels were three
times higher than the control group in the stem and leaves. The highest induction in SOD and GR activities were determined
at 200 mg/L Pb group in stem, whereas CAT and AP activities were higher than other groups at the concentration of 250 and
100 mg/L Pb, respectively. The increase in CAT activity was found to be greater than GR, SOD, and AP activities in stems of
watercress under Pb treatment. Both lead accumulation and antioxidant enzyme responses were higher in stems than in leaves.
The results of the present study suggested that the induction in antioxidant responses could be occurring as an adaptive mechanism
to the oxidative potential of lead accumulation. 相似文献
6.
The aim of the work was to investigate antitumoral effect of essential oils on cancer cells and their possible protective
(antioxidant) effects against hydrogen peroxide-induced cytotoxicity. Also, in vitro antioxidant properties of essential oils
and aqueous extracts from wild form and cultivated form of Salvia pisidica were compared. 相似文献
7.
Sahin E Gümüşlü S 《Comparative biochemistry and physiology. Toxicology & pharmacology : CBP》2007,144(4):342-347
We determined the effects of immobilization stress on antioxidant status, protein oxidation and lipid peroxidation in brain, liver, kidney, heart and stomach of rats. Sixteen male Wistar rats (3 months old) were divided into controls (C) and immobilization stress group (IS). IS rats were immobilized for 180 min/day for 15 days. Plasma corticosterone levels were increased in IS group. Copper,zinc-superoxide dismutase activities were increased in brain, liver and kidney, but decreased in the heart and stomach after immobilization. Catalase activities were increased in brain, kidney and heart, and decreased in liver and stomach. Selenium-dependent glutathione peroxidase activities were decreased in brain and kidney, but increased in heart and stomach. Reduced glutathione levels were decreased, while protein carbonyl, conjugated dienes and thiobarbituric acid-reactive substances levels were increased in all tissues. Our results showed that the response of antioxidant defense system to stress differs for each tissue, and protein oxidation and lipid peroxidation is induced by immobilization stress in peripheral tissues. 相似文献
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9.
Dorothee Rickert Marc O Scheithauer Saadet Coskun Andreas Lendlein Steffen Kelch Ralf-Peter Franke 《Biomedizinische Technik》2006,51(3):116-124
The stability and tight integration into adjacent tissue of a novel, degradable, elastic copolymer were examined in an animal model. The biomaterial was used for the reconstruction of a gastric wall defect in Sprague-Dawley rats (n=42) to test the polymeric material under the extreme chemical, enzymatical and mechanical conditions of the stomach. In the control group (n=21) the same defect of the gastric wall was primarily closed without biomaterial implantation. In the baseline group (n=21) the animals were kept under standard conditions without any surgical procedure. The implantation periods were 1 week, 4 weeks and 6 months. The animals' weight was determined preoperatively and before explantation. After explantation, air was pumped into the stomach and the pressure was measured by using a pressure-gauge in order to test whether the surgically produced union of the stomach wall and the polymer patch was gas-tight. After 1 week of implantation time a statistically significant increase of the body weight of the animals was found only in the baseline group. Four weeks and 6 months after the abdominal surgical procedure, a statistically significant increase of the animals' weight was found in the implantation group, the control and the baseline group. Gastrointestinal complications like fistula, perforation or peritonitis did not occur in any of the animals. The measurement of the stomach pressure after maximal gas insufflation did not show significant differences between the implantation group, the control and the baseline group in any of the time periods investigated. Despite very high strains of the gastric wall, no gas leakage was detected. There was a tight connection between the polymer and the adjacent stomach wall in all animals investigated. An adequate mechanical stability of the biomaterial was detectable under the extreme pathophysiological conditions of the stomach milieu. A fast and unfavourable degradation of the degradable polymer was not found in any of the animals. Further investigations are needed to analyse the mechanisms of the tissue integration of the biomaterial as well as the degradation kinetic of the polymer and the process of the tissue remodeling. The knowledge of these processes is necessary to adapt the novel biomaterial and thus prepare it for the use and implantation in different body locations and to develop novel therapeutical options in medicine. 相似文献
10.
Ustundag B Yilmaz E Dogan Y Akarsu S Canatan H Halifeoglu I Cikim G Aygun AD 《Mediators of inflammation》2005,2005(6):331-336
It has been well documented that human milk contains several immunomodulator components which are important during infant period when the newborn's immune system is still under development. In this study, we aim at examining levels of cytokines, zinc (Zn), and copper (Cu) in milk from mothers of premature and mature infants, and comparing changes during lactation periods consequently. Milk was collected from total of 40 mothers (group M: mothers of mature infants, n = 20; group PM: mothers of premature infants, n = 20) from four lactation stages: colostrum (0-7 days), transitional (7-14 days), mature milk (21 days), and mature milk (2nd month). Levels of cytokines (interleukin [IL]-lbeta, IL-2, IL-6, IL-8, tumor necrosis factor-alpha [TNF-alpha]) were determined by chemiluminesence method, whereas atomic absorption spectrophotometer was used for the determination of Zn and Cu levels. Cytokine levels were determined to be high in colostrum and transient milk from mothers of full-term infants, whereas their levels were reduced drastically in the 21st day and the 2nd month milk (P < .01, P < .001). Similar trends were observed in milk from mothers of premature infants, but cytokine levels were significantly lower in colostrum compared to colostrum from mothers of mature infants (P < .01). The differences in cytokine levels were continuous in transient milk (P < .05) and mature milk (21 days) (P < .05), whereas there was no statistically significant differences between milk from both groups of mothers in the 2nd month (P > .05). Zn levels in milk from mothers of premature infants were significantly lower compared to the ones from mothers of mature infants (P < .01) and these differences continued through the 2nd month. Although Cu levels were lower in milk from mothers of premature infants, there was no statistically significant difference except colostrum (P > .05). Our results clearly demonstrate that the level of immunomodulating agents such as cytokines and trace elements in milk from mothers of premature infants is less than the level of the same agents in milk from mothers of full-term infants. Although there are commercially available products for infant feeding, human milk is still the best natural nutrient for newborns. Therefore, when premature infants are breastfed, necessary precautions such as supplemantary diets must be considered for possible infections and risks related with immune system deficiency. 相似文献