Impaired seminal antioxidant capacity in human semen with hyperviscosity or oligoasthenozoospermia.

Antioxidant capacity of seminal plasma was evaluated in 120 semen samples subdivided into asthenozoospermic and oligoasthenozoospermic specimens with normal consistency and into asthenozoospermic and oligoasthenozoospermic specimens with hyperviscosity. Semen samples (n = 25) from normozoospermic donors were used as a control group. Scavenger antioxidant capacity of reactive oxygen species was evaluated by superoxide dismutase and catalase activity measurements, whereas the chain-breaking antioxidant efficiency was detected by total antioxidant status assessment. In semen with normal viscosity, unaltered enzymatic and nonenzymatic antioxidant capacity was revealed in the asthenozoospermic specimens, whereas low superoxide dismutase activity was detected in oligoasthenozoospermic samples. On the contrary, impairment of both the scavenger and chain-breaking antioxidative systems was revealed in asthenozoospermic and oligoasthenozoospermic hyperviscous ejaculates, regardless of sperm count. Catalase activity and total antioxidant status values were also reduced in the 2 subgroups of hyperviscous ejaculates compared with their respective matched controls, whereas similar superoxide dismutase activities were detected in oligoasthenozoospermic samples with normal and high consistencies. These results suggest that asthenozoospermia could be related to an antioxidant deficiency only in combined ejaculate pathologies, and that a severe impairment of the low and high molecular weight seminal antioxidative capacities could be associated with semen hyperviscosity.     

Micropropagation, antinociceptive and antioxidant activities of extracts of Verbena litoralis Kunth (Verbenaceae)

This work describes an efficient micropropagation protocol for Verbena litoralis and the study of the antinociceptive and antioxidant activities in extracts of this species. For the establishment in vitro, surface-sterilization procedures and PVPP showed high efficiency in fungal-bacterial contamination and phenol oxidation controls. Nodal segments cultivation in MS medium supplemented with 6-benzyladenine (7.5 μM)/α-naphthaleneacetic acid (NAA; 0.005 μM) induced multiple shoots. Elongated shoots were rooted with IAA (0.2 μM). Acclimatization rates were elevated and the plants showed the typical features of this species. The hexanic fraction (HF) of powdered leaves presented a radical scavenging activity with IC(50) = 169.3 μg mL(-1). HF showed a non-dose dependent analgesic activity in the writhing test; its antinociceptive activity in the hot plate test was restricted to 500 mg kg(-1), which is the highest dose. The results of this study showed the potential of tissue culture on conservation and large scale multiplication and confirmed the traditional folk medicine use of V. litoralis.     

Antioxidant activity and flavonoid content of Clusia fluminensis Planch. & Triana

Clusia fluminensis Planch. & Triana (Clusiaceae Lindl.) is a native species found in regions of high luminosity and water restriction. The aim of this study was to evaluate the antioxidant activity of Clusia fluminensis crude extracts through the scavenging of the stable free radical DPPH, and the determination of flavones and flavonols content in these extracts. The fruit acetonic extract showed the lowest EC50 value (2.71 ± 0.34 g extract / g DPPH), the lowest percentage of remaining DPPH at the concentrations of 125 and 250 μg/mL (about 4% in both), and also the greatest percentage of flavones and flavonols (13.93 ± 0.21 %). Statistical analysis suggests a positive correlation between the presence of flavonoids and the antioxidant activity of this extract. From the obtained results it can be inferred that the acetonic extract of C. fluminensis fruits is an interesting target for the search of substances with antioxidant activity, especially flavonoids.     

Cyclosporine effects on the antioxidant capacity of rat renal tissues

OBJECTIVE: Cyclosporine (CsA) has been shown to improve long-term survival after organ transplantation. However, CsA therapy is associated with a variety of side effects, among which nephropathy is the major one. Recent studies have suggested increased oxidative stress as a cause of drug nephrotoxicity. Therefore, this study was designed to evaluate the effects of CsA administration on the antioxidant capacity of kidney tissue. METHODS: Adult male Sprague-Dawley rats were randomly assigned into 2 groups: one group received CsA (25 mg/kg/d, IP for 2 weeks) and a control group (no CsA administration). After 2 weeks, the kidneys of the rats from both groups were removed under anesthesia. A 50 mg fresh kidney tissue sample was homogenized in ice-cold phosphate buffer. Total antioxidant capacity (Ferric Reducing Ability of Plasma [FRAP]) in the homogenates was assayed based on the Benzie spectrophotometric method. RESULTS: FRAP in the kidney tissues had been significantly decreased by 2 weeks of CsA administration when compared with control rats (P<.05). CONCLUSIONS: These data suggested that CsA administration may decrease the antioxidant capacity of renal tissues. More studies on the evaluation of the protective effects of antioxidant therapy against CsA nephrotoxicity are underway.     

Studies on the tumor-promoting activity of polyethylene: inhibitory activity of metabolic cooperation of polyethylene films containing an antioxidant

Tumor-promoting activity, inhibitory activity on the gap-junctional intercellular communication of polyethylene (PE) film containing a model antioxidant, 2,2'-methylene-bis(4-methyl-6-tert-butylphenol) (MBMBP), at various amounts was assessed by V79 metabolic cooperation (MC) assay. The extracts prepared from PE film containing MBMBP showed the inhibitory activities and the potencies of the inhibitory activities depended on the amount of MBMBP involved in the film, whereas the extract prepared from MBMBP-free PE film did not show any inhibitory activities. However, the inhibitory activities were observed when MC assay was carried out on the surface of the MBMBP-free film. These findings indicate that tumor-promoting activity of PE film is influenced by the surface property of the film as well as by amount and kind of additives incorporated.     

Seasonal variation in uterotonic activity of Rhoicissus tridentata extracts.

BACKGROUND: Rhoicissus tridentata lignotubers are widely used in southern African traditional pregnancy-related remedies. OBJECTIVES: To determine the seasonal variation in contractile activity of extracts from different parts of the plant. METHODS: Isolated rat uterus tissue was used to compare the contractile activity of crude aqueous extracts of R. tridentata made from plant material harvested every 3 months over a period of 2 years. RESULTS AND CONCLUSIONS: The activity of the plant extracts from plants harvested in summer and autumn were 4-5-fold higher than extracts from plants harvested in winter or spring. The tubers stimulated the greatest degree of contractions, followed by the stems, roots and leaves. These results highlight the need to standardise the timing of harvesting R. tridentata.     

Cactus flower extracts may prove beneficial in benign prostatic hyperplasia due to inhibition of 5α reductase activity, aromatase activity and lipid peroxidation

The cactus flower is deemed to be helpful in benign prostatic hyperplasia (BPH) therapy, although there is no published information regarding its clinical effect in patients and on the mechanism of its biological activity. The present study evaluated the ability of cactus flower extracts to exert an effect on BPH through possible inhibition of such processes as lipid peroxidation, androgen aromatization and testosterone reduction. Cactus flower extracts indeed inhibited aromatase and 5α reductase activity in cultured foreskin fibroblasts, and also in human placental and prostatic homogenates. The inhibitory activity in both instances was associated with the dichloromethane or ethanol (methanol) extracts, while a marked antioxidative activity was associated with the aqueous extract. The finding that cactus flower extracts interfere concurrently in vitro with aromatase and reductase activity as well as with free radical processes suggests that these substances may prove beneficial in BPH treatment. Received: 15 August 1997 / Accepted: 31 March 1998     

Epoetin treatment improves red blood cell and plasma antioxidant capacity in hemodialysis patients

The efficiency of human recombinant epoetin in alleviating anemia in hemodialyzed patients has been well documented. However, the effects of rhEPO therapy in correction of antioxidant capacity are not completely explained. In this study we examined both extracellular (plasma) and intracellular (red blood cells) antioxidant potential in hemodialyzed patients before and after three and six months of epoetin treatment by evaluating markers of oxidative stress (malondialdehyde) and antioxidant capacity (thiol groups, superoxide dismutase, and glutathione peroxidase). Six months of treatment with epoetin was followed by significant increases in thiol groups, superoxide dismutase and glutathione peroxidase activities in both plasma and red blood cells of hemodialyzed patients. Hence, during accelerated erythropoiesis, an increase in the number of young hematopoietic cells may replenish erythrocyte superoxide dismutase and glutathione peroxidase activity. However, the consequences of an imbalance between enzymatic antioxidant system (higher superoxide dismutase and lower glutathione peroxidase activity) that exists in these patients are the very high red blood cell and plasma malondialdehyde levels. These results suggest that, in spite of epoetin treatment and improvement in red blood cells and plasma antioxidant capacity, the production of reactive oxygen species overwhelms the intracellular and extracellular antioxidant capacity.     

An update on the role of medical treatment including antioxidant therapy in varicocele

Varicocele-associated male infertility has classically been managed using surgery or assisted reproductive techniques. With increasing evidence of oxidative stress as a pathophysiological factor in varicocele-associated infertility, medical therapy especially antioxidants might become a treatment option with lower risks. We reviewed the existing literature on the role of various medical agents in the management of male infertility attributed to varicoceles. Medical therapy is typically evaluated in three different situations such as (a) comparison of two drugs or one drug with placebo, (b) comparison of drugs versus surgery, and (c) comparison of drugs as adjuvant therapy with surgery versus drug therapy alone. Due to heterogeneity of data and lack of well-conducted studies, there is insufficient data to recommend routine use of medical therapy for men with varicocele-associated infertility and surgery remains the treatment of choice. Pregnancy and live birth rates are usually not reported in most studies and mere improvement in sperm parameters or antioxidant capacity is insufficient to support its routine use. Antioxidant therapy is a potential option due to its theoretical benefit, data from preclinical studies, and lack of major side effects. Adjuvant therapy with antioxidants after surgical repair of varicocele may improve the outcome and is a potential area for further research.     

Effect of the cryopreservation process on the activity and immunolocalization of antioxidant enzymes in ram spermatozoa

In this study, certain enzymes in ram semen involved in reactive oxygen species elimination and their changes during the cryopreservation process were characterized in order to investigate the hypothesis that the antioxidant defense system is involved in the maintenance of frozen sperm quality. Glutathione reductase (GR), glutathione peroxidase (GPx), and superoxide dismutase (SOD) activities were quantified in ram sperm samples subjected to cooling and freezing/thawing processes. In addition, their distribution on the sperm surface and the changes due to cryoinjury were determined by indirect immunofluorescence. SOD showed the highest antioxidant activity, which was also twice as high in fresh and cooled samples as in frozen/thawed ones. Enzymatic activity of GPx and GR showed no significant change throughout the freezing process. Seminal plasma proteins (SPPs) added alone or with other compounds showed a protective effect and accounted for an increase in the sperm quality parameters and enzyme activity levels not only in the fresh sample but also after cooling and freezing/thawing. These antioxidant enzymes were distributed over several sperm regions, and we were able to define several subpopulations according to the obtained sperm immunofluorescence patterns. The sperm membrane distribution of SOD, GPx, and GR changed considerably during cryopreservation, and the type and percentage of the immunofluorescence patterns found in fresh samples were severely modified. This remodeling was strongly affected by the use of different cryoprotectants. The mixture of SPPs, oleic/linoleic acids, and vitamin E was able to partly maintain and recover the fresh enzyme distribution, particularly of SOD.     

Effect of spermatic vein ligation on seminal total antioxidant capacity in terms of varicocele grading

We aimed to assess the effect of spermatic vein ligation on seminal total antioxidant capacity (TAC) in patients with varicocele. Twenty infertile male patients with varicocele and 20 normal fertile men (control group) were included in the study. All the male patients were diagnosed with primary infertility and varicocele. The patients with varicocele were divided into two groups as nonpalpable (GI) (eight patients) and palpable (GII-III) (12 patients) varicocele groups. All the patients underwent microsurgical spermatic vein ligation. Seminal TAC levels and sperm parameters were evaluated in all the patients. Preoperative sperm count, sperm motility, sperm morphology and seminal TAC levels with equivalent figures 3-6 months after spermatic vein ligation and the same values of the control group were compared. There was a statistically significant increase in the total seminal antioxidant capacity level after spermatic vein ligation, and there was a statistically significant increase in the sperm count, sperm motility and spermatozoa with normal morphology. However, evaluation of the patients for varicocele grade showed a statistically significant increase in the TAC level only in the GII-III varicocele group. Spermatic vein ligation can improve the total seminal antioxidant capacity levels especially in patients with middle and high grade varicocele.     

Tissue antioxidant capacity during anesthesia: propofol enhances in vivo red cell and tissue antioxidant capacity in a rat model.

The effects of anesthesia on ischemia-reperfusion injury are of considerable scientific and clinical interest. We examined the effects of propofol (known to possess antioxidant activity) and halothane (devoid of antioxidant activity in vitro) on tissue and red blood cell (RBC) antioxidant capacity. Adult male Wistar rats were anesthetized with halothane 0.5%-1.0% (n = 7), propofol 500 microg x kg(-1) x min(-1) with halothane 0.25%-0.5% (small-dose propofol; n = 9), or propofol 2000 microg x kg(-1) x min(-1) (large-dose propofol; n = 8) for 45 min. Blood and tissue samples of liver, kidney, heart, and lung were then harvested for in vitro exposure to a peroxidizing agent. Red cell malondialdehyde and tissue thiobarbituric acid reactive substances were determined spectrophotometrically. Antioxidant capacities of blood and tissues in the Large-Dose Propofol group, and of blood and all tissues except lung in the Small-Dose Propofol group, were increased significantly compared with halothane (P < 0.003). The increases in tissue antioxidant capacities varied in their magnitude: RBC > liver > kidney > heart > lung. There was a high correlation between changes in RBC susceptibility to oxidative damage and corresponding changes in tissues. These findings demonstrate that large-dose propofol significantly enhances tissue antioxidant capacity, and RBC antioxidant capacity can serve as a functional measure of tissue activity, in vivo. IMPLICATIONS: We designed this study to investigate the antioxidant effects of propofol in various tissues in a rat model. Pretreatment of animals with propofol led to a reduction in the susceptibility to an in vitro oxidative stress of five different tissues investigated, demonstrating the drug's ability to limit oxidative injury. This may have future application in limiting organ dysfunction after periods of tissue ischemia (which results in oxidative damage).     

Altered antioxidant capacity in human renal cell carcinoma: role of glutathione associated enzymes

PURPOSE: We aimed to discern the role of glutathione (GSH) associated enzymes in maintaining high GSH levels in renal cell carcinoma (RCC) of the clear cell type and analyze RCC enzyme antioxidant capacity. Since changes in cellular redox balance in RCC might also be related to alterations of glutathione S-transferase (GST) phenotype, GST class alpha and pi expression was also explored. METHODS AND MATERIALS: Human kidney specimens of tumor and distant nontumor regions were obtained from 15 patients with RCC at the time of surgery. The activities of GSH-replenishing enzymes, gamma-glutamylcysteine synthetase (gamma-GCS), gamma-glutamyl transferase (gamma-GT), and glutathione reductase (GR), as well as the activities of antioxidant enzymes glutathione peroxidase (GPX) and catalase (CAT) were determined spectrophotometrically. GST alpha and pi class expression was determined by immunoblot. RESULTS: In the course of renal cancerization, significant changes appear in the activities of GSH-replenishing and antioxidant enzymes. The activity of the key enzyme of GSH synthesis, gamma-GCS, is up-regulated (P < 0.001), while the activities of gamma-GT and GR are down-regulated in renal tumors compared to nontumor tissue (P < 0.001 and P < 0.05, respectively). Activities of GPX and CAT were also down-regulated (P < 0.001 and P < 0.05, respectively) in RCC. Changes in enzyme antioxidant capacity in RCC were associated with decreased GST class alpha (P < 0.001) and unchanged GST pi expression at the protein level. CONCLUSIONS: Changes in redox status in RCC as a consequence of decreased enzyme antioxidant capacity, together with altered GST alpha expression, may be important factors in development and tumor growth. The up-regulation of gamma-GCS and high levels of GSH in RCC may be an attempt to limit injury caused by oxidative stress.     

Silymarin, the antioxidant component of Silybum marianum, prevents sepsis-induced acute lung and brain injury

BACKGROUND: Sepsis is associated with enhanced generation of reactive oxygen species, which leads to multiple organ dysfunctions. Based on the potent antioxidant effects of silymarin, we investigated the putative protective role of silymarin against sepsis-induced oxidative damage in lung and brain tissues. MATERIALS AND METHODS: Sepsis was induced by cecal ligation and perforation (CLP). Sham and CLP groups received either vehicle or silymarin (50 mg/kg, p.o.) or 150 mg/kg i.p. N-acetylcysteine (NAC) for 10 days prior and immediately after the operation. Six hours after the surgery, rats were decapitated and blood was collected for the measurement of proinflammatory cytokines (tumor necrosis factor-alpha, interleukin-1 beta [IL-1 beta], and IL-6) levels, lactate dehydrogenase activity, and total antioxidant capacity. Lung and brain samples were taken for the measurement of malondialdehyde and glutathione levels, myeloperoxidase activity, thromboplastic activity, and also for histological assessment. Formation of reactive oxygen species in tissue samples was monitored by using chemiluminescence technique with luminol and lusigenin probe. RESULTS: Sepsis increased serum TNF-alpha, IL-1 beta, IL-6 levels, and lactate dehydrogenase activity and decreased total antioxidant capacity. On the other hand, tissue glutathione levels were decreased while malondialdehyde levels and myeloperoxidase activity were increased in both the lung and the brain tissues due to CLP. Furthermore, luminol and lucigenin chemiluminescence were significantly increased in the CLP group, indicating the presence of the oxidative damage. Silymarine and NAC treatment reversed these biochemical parameters and preserved tissue morphology as evidenced by histological evaluation. CONCLUSIONS: Silymarin, like NAC, reduced sepsis-induced remote organ injury, at least in part, through its ability to balance oxidant-antioxidant status, to inhibit neutrophil infiltration, and to regulate the release of inflammatory mediators.     

Sperm immobilization activity of Allium sativum L. and other plant extracts

Aim: To identify possible spermicidal agents through screening a number of edible medicinal plants with antimicrobial activity. Methods: Initial screening was made on the basis of ram cauda epididymal sperm immobiliza-tion immediately after addition of extracts. The most potent extract was selected and was evaluated on both ram and human spermatozoa. To unravel its mode of action several sperm functional tests were carried out, namely viability of cells, hypo-osmotic swelling test for membrane integrity and assays of membrane-bound enzyme 5‘-nucleotidase and acrosomal marker enzyme acrosin. Results: The crude aqueous extract of the bulb ofAllium sativum L. Showed the most promising results by instant immobilization of the ram epididymal sperm at 0.25 g/mL and human ejaculated sperm at 0.5 g/mL. Sperm immobilizing effects were irreversible and the factor of the extract responsible for immobilization was thermostable up to 90℃. On boiling at 100℃ for 10 minutes, this activity was markedly reduced. Moreover, this extract was able to cause aggregation of ram sperms into small clusters after 30 minutes of incubation at 37℃. However this property was not found in human spermatozoa. More than 50 % reduction in sperm viability and hypo-osmotic swelling occurred in treated sperm as compared with the controls, indicating the possibility of plasma membrane disintegration which was further supported by the significant reduction in the activity of membrane bound 5‘‘-nucleotidase and acrosomal acrosin. Conclusion: The crude aqueous extract of A. Sativum bulb possesses spermicidal activity in vitro. (Asian J Androl 2003 Jun, 5:131-135 )     

Glutathione S-transferase-P1 expression correlates with increased antioxidant capacity in transitional cell carcinoma of the urinary bladder

OBJECTIVES: Our aim was to perform a comprehensive analysis of the antioxidant capacity of transitional cell carcinoma (TCC) of urinary bladder and discern the role of enzymes associated with glutathione (GSH) in maintaining high GSH levels in these tumours. Because the redox-sensitive protein glutathione S-transferase P1 (GSTP1) might provide an important link between high antioxidant capacity and inhibition of apoptotic pathways, we also explored how the redox state in tumour cells interacts with the expression of GSTP1. METHODS: We examined spectrophotometrically the specific activities of GSH-replenishing enzymes involved in GSH synthesis (gamma-glutamylcysteine synthetase, gamma-GCS), GSH regeneration (glutathione reductase, GR), and antioxidant protection (glutathione peroxidase, GPX; superoxide dismutase, SOD) in the cytosolic fraction of tumours and the surrounding normal tissue of 30 TCC patients. GSTP1-1 expression was also analyzed. RESULTS: We found a significant increase in the activity of both GSH-replenishing and antioxidant enzymes as well as enhanced GSTP1-1 expression in tumours in comparison with adjacent normal uroepithelium. Mean gamma-GCS and GR activities in tumours were about 4- and 2-fold higher, respectively, than in corresponding normal tissue. Expression of GSTP1 correlated significantly with GSH level and gamma-GCS and GR activities. GPX and SOD activities in TCC were also markedly increased. CONCLUSIONS: Enhanced GSH-replenishing pathways account for increased GSH levels in TCC. Upregulated GPX and SOD also contribute to high antioxidant potential in TCC. Under such conditions, expression of redox-sensitive GSTP1 protein is upregulated.     

Effect of ghrelin on total antioxidant capacity,lipid peroxidation,sperm parameters and fertility in mice against oxidative damage caused by cyclophosphamide

Cyclophosphamide is a drug used for chemotherapy and as an immune‐suppressive in the organ transplantation. Despite its many clinical implications in the treatment of cancers, this drug has toxic effects on the reproductive system. This study aimed to evaluate the effect of ghrelin against the damages caused by cyclophosphamide. In this experimental study, 40 male mice were randomly divided into four groups: (i) control; (ii) cyclophosphamide; (iii) cyclophosphamide + ghrelin; and (iv) ghrelin. Cyclophosphamide (100 mg/kg body weight), once a week, and ghrelin (80 μg/kg body weight), daily, were administered intraperitoneally for 5 weeks. After 5 weeks, the epididymides were removed and the lipid peroxidation, total antioxidant capacity and sperm parameters were examined. The fertility rate was evaluated by performance in vitro fertilisation. In the mice exposed to cyclophosphamide, the number of spermatozoa and viability, as well as total antioxidant capacity, decreased significantly (p < .05). The increase in the abnormal sperm and MDA levels was observed (p < .05). In addition, the fertility rate decreased in this group, while the use of ghrelin significantly improved the above disorders in the treatment group (p < .05). The findings of this study showed that ghrelin attenuates negative effects caused by cyclophosphamide in the sperm parameters and enhances the fertility.     

Endophytic mediation of reactive oxygen species and antioxidant activity in plants: a review

Reactive oxygen species are in all types of organisms from microbes to higher plants and animals. They are by-products of normal metabolism, such as photosynthesis and respiration, and are responsive to abiotic and biotic stress. Accumulating evidence suggests reactive oxygen species play a vital role in programmed cell death, stress responses, plant defense against pathogens and systemic stress signaling in conjunction with antioxidant production. Here, we propose that reactive oxygen species and antioxidants, as both universal and evolutionarily conserved, are likely to play important role(s) in symbiotic interactions. To support this hypothesis we review the root and foliar fungal endophyte literature specific to fungal-plant symbiotum production of reactive oxygen species and antioxidants in response to stress. These asymptomatic fungi can produce antioxidants in response to both biotic and abiotic stress when grown in culture as well as in planta. In addition, there is a growing but nascent literature reporting a significant impact of endophyte colonization on the antioxidant activity of colonized (E+) hosts when compared to uncolonized (E-) hosts, especially when exposed to stress. Here we summarize general patterns emerging from the growing literature specific to antioxidant activity of endophytes in colonized hosts and bring up possible future research questions and approaches. The consequences of changes in reactive oxygen species production and increased antioxidant activity in the symbiotum appear to be beneficial in many instances; but costs are also indicated. Unexplored questions are: 1) to what extent do antioxidants originating from the fungal endophyte mediate host metabolism, and thereby control host responses to endophyte colonization; (2) what role do fungal, plant, or symbiotum produced reactive oxygen species and antioxidants have in determining symbiotic outcome between extremes of pathogenicity and mutualism; and (3) what role if any, do the production of reactive oxygen species and their antioxidant counterparts play in the symbiotum??s ability to respond to changing selection pressures? If as the literature suggests, such endophyte imposed mediation can be utilized to foster increases in plant production in resource limited habitats then the utilization of fungal endophytes may prove useful in agronomic and conservation settings.     

大剂量沐舒坦对急性呼吸窘迫综合征患者抗氧化能力的影响

目的　研究大剂量沐舒坦对急性呼吸窘迫综合征 (ARDS)患者抗氧化能力的影响。方法　选择ARDS患者 4 2例 ,随机分成对照组 (A组 ,n =2 0 )和观察组 (B组 ,n =2 2 )。A组每天给予单纯生理盐水 5 0 0ml静脉滴注 ,B组每天给予沐舒坦 2 0mg/kg加生理盐水 5 0 0ml静脉滴注 ,连续应用 7d。比较两组患者在肺损伤程度、血气指标和血清超氧化物歧化酶 (SOD)活力等方面的变化和差异。结果　用药后B组患者的血气指标和肺损伤评分明显改善 ,血清SOD活力显著升高 (P <0 0 5或P <0 0 1) ,与A组比较均有显著性差异 (P <0 0 5或P <0 0 1)。结论　临床应用大剂量沐舒坦可增强ARDS患者的抗氧化能力 ,有利于其呼吸功能的恢复     

Quantification of the nonenzymatic fast and slow TRAP in a postaddition assay in human seminal plasma and the antioxidant contributions of various seminal compounds

Total radical-trapping antioxidant potential (TRAP) measurements of human seminal plasma (N = 25) were performed by using a post-addition assay based on trapping 2,2' Azino-bis(3-ethylbenzthiazoline-6-sulfonic acid) (ABTS) radicals. This method enables the antioxidant capacity of human seminal plasma and its constituents to be quantified. The standard procedure consisted of determination of the Trolox equivalent antioxidant capacity (TEAC) after incubating the test sample in the ABTS radical solution for 10 seconds (fast TRAP) and 300 s (total TRAP). Interestingly, seminal plasma showed a fast TRAP and a high slow TRAP (Total TRAP - Fast TRAP). The final total TRAP of seminal plasma is about 10 times higher than that of blood plasma. Various components of seminal plasma contribute to its fast TRAP; 37% can be attributed to vitamin C, uric acid, and tyrosine; proteins and polyphenolic compounds contribute a further 57%. In contrast, the slow TRAP was attributed to vitamin C (1%), uric acid (2%), and tyrosine (15%) and to proteins and polyphenolic compounds (33%). It was not possible to account for the remaining 49%. Neither known putative antioxidants, such as spermine, pyruvate, and taurine, nor other seminal compounds, such as carnitine, sialic acid, fructose, spermidine, glycerophosphorylcholine, and hyaluronic acid, contributed to any significant radical-trapping activity at a standard concentration of 1 mM. Of the amino acids, only tyrosine possessed a slow TRAP, and it is present at a high concentration in seminal plasma. Glutathione and hypotaurine show high fast and slow TRAPs, respectively. However, because of their low concentration in seminal plasma, their contribution to the TRAP is negligible. In conclusion, seminal plasma possesses a high antioxidant buffer capacity that protects spermatozoa from oxidative stress. Moreover, these findings suggest that the fast and slow TRAPs may have an important role as infertility markers and treatment targets in future antioxidant therapies.