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1.
The effects of vitamin E and selenium intake on oxidative stress and plasma lipids in hamsters fed fish oil 总被引:5,自引:0,他引:5
The aim of the present work was to test the effects of large-dose supplementation of vitamin E (Vit E) and selenium (Se),
either singly or in combination, on fish oil (FO)-induced tissue lipid peroxidation and hyperlipidemia. The supplementation
of Se has been shown to lower blood cholesterol and increase tissue concentrations of the antioxidant glutathione (GSH); however,
the effects of Se supplementation, either alone or in combination with supplemental Vit E, on FO-induced oxidative stress
and hyperlipidemia have not been studied. Male Syrian hamsters received FO-based diets that contained 14.3 wt% fat and 0.46
wt% cholesterol supplemented with Vit E (129 IU d-α-tocopheryl acetate/kg diet) and/or Se (3.4 ppm as sodium selenate) or that contained basal requirements of both nutrients.
The cardiac tissue of hamsters fed supplemental Se showed increased concentrations of lipid hydroperoxides (LPO) but decreased
oxidized glutathione (GSSG) concentrations. The higher concentrations of LPO in the hearts of Se-supplemented hamsters were
not lowered with concurrent Vit E supplementation. In the liver, Se supplementation was associated with higher Se-dependent
glutathione peroxidase activity and an increase in the GSH/GSSG ratio, whereas a lower hepatic non-Se-dependent glutathione
peroxidase activity was seen with Vit E supplementation. Supplemental intake of Se was associated with lower plasma concentrations
of total cholesterol and low density lipoprotein cholesterol plus very low density lipoprotein cholesterol. In view of the
pro-oxidative effects of Se supplementation on cardiac tissue, a cautionary approach needs to be taken regarding the plasma
lipid-lowering properties of supplemental Se. 相似文献
2.
Participants from 5 groups with mean ages of 6, 8, 10, 22, and 72 yrs were tested on a series of speeded number discriminations: 1 vs 2, 3 vs 4, 6 vs 7, and 8 vs 9. The primary measure of interest (response time slope as a function of number size) decreased with age for numbers in the 1–4 range. However, a U-shaped age function emerged in the 6–9 range, with larger slopes for children and senior adults, and the smallest slopes for young adults. These data suggest that different processes are involved in enumerating small and large numbers of items. It is argued that subitizing, the process for small numbers, makes only minimal demands on spatial attention and thus shows developmental improvements without any decline in old age. In contrast, counting, the process for large numbers, requires sophisticated coordination of spatial attention, which has previously been shown first to improve and then decline over the life span. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
3.
The gambler's fallacy was examined in terms of grouping processes. The gambler's fallacy is the tendency to erroneously believe that for independent events, recent or repeated instances of an outcome (e.g., a series of "heads" when flipping a coin) will make that outcome less likely on an upcoming trial. Grouping was manipulated such that a critical trial following a run of heads or tails was grouped together with previous trials (i.e., the last trial of "Block 1") or was the first trial of another group (the first trial of "Block 2"). As predicted, the gambler's fallacy was evident when the critical trial was grouped with the previous trials, but not when it was arbitrarily grouped with the next block of trials. Discussion centres on the processes underlying the gambler's fallacy and practical implications of these findings. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
4.
Timothy N. Trick 《工程教育杂志》1994,83(1):57-62
Integrated circuit technology is causing rapid change in governments and industry. Never before has so much information been available so quickly and easily. Globally governments and industries are in a period of rebirth-a global renaissance. More than ever before engineers must be prepared for a period of rapid change. More and more powerful and complex hardware and software will be embedded in our systems. Electrical and computer engineers are developing these powerful technologies, and they must be prepared and encouraged to assume more leadership in industry, government, and the university. 相似文献
5.
Applicability of light-emitting diodes as light sources for active differential optical absorption spectroscopy measurements 总被引:1,自引:0,他引:1
We present what is to our knowledge the first use of light-emitting diodes (LEDs) as light sources for long-path differential optical absorption spectroscopy (LP-DOAS) measurements of trace gases in the open atmosphere. Modern LEDs represent a potentially advantageous alternative to thermal light sources, in particular to xenon arc lamps, which are the most common active DOAS light sources. The radiative properties of a variety of LEDs were characterized, and parameters such as spectral shape, spectral range, spectral stability, and ways in which they can be influenced by environmental factors were analyzed. The spectra of several LEDs were found to contain Fabry-Perot etalon-induced spectral structures that interfered with the DOAS evaluation, in particular when a constant temperature was not maintained. It was shown that LEDs can be used successfully as light sources in active DOAS experiments that measure NO2 and NO3 near 450 and 630 nm, respectively. Average detection limits of 0.3 parts in 10(9) and 16 parts in 10(12) respectively, were obtained by use of a 6 km light path in the open atmosphere. 相似文献
6.
Monica?Iskandar Eleonora?Swist Keith?D?Trick Bingtuan?Wang Mary?R?L'Abbé Jesse?BertinatoEmail author 《Nutrition journal》2005,4(1):35
Background
Small increases in zinc (Zn) consumption above recommended amounts have been shown to reduce copper (Cu) status in experimental animals and humans. Recently, we have reported that copper chaperone for Cu/Zn superoxide dismutase (CCS) protein level is increased in tissues of overtly Cu-deficient rats and proposed CCS as a novel biomarker of Cu status. 相似文献7.
Describes a 3-wk project in which psychology practicum students assumed primary responsibility for patient care on the psychiatric unit of a large medical center hospital. The project had interesting implications for issues related to clinical training and professional relationships. The pace was intense and demanding and students became totally involved in treating the patients and learning about themselves. Each student worked with about 7 patients primarily through group therapy and family counseling. It is felt that this training model was more likely to test the student's commitment to psychology and to solidify a professional identity than more traditional programs. The project was unique in that the only doctor-patient relationship that the patients had was with the psychology student. 2 physicians were available for medical consultation. Informal observations and analysis of rating scales filled out by the patients indicate that they valued highly the contribution of the students. It is concluded that current trends in medicine toward comprehensive care and family practice necessitate the physician's relinquishment of his exclusive relationship with the patient and to bring in nonmedical specialists on a peer basis. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
8.
Lignans are phenylpropane dimers that are biosynthesized via the phenylpropanoid pathway, in which pinoresinol lariciresinol reductase (PLR) catalyzes the last steps of lignan production. Our previous studies demonstrated that the contents of lignans in various wheat cultivars were significantly associated with anti-tumor activities in APC(Min) mice. To enhance lignan biosynthesis, this study was conducted to transform wheat cultivars ('Bobwhite', 'Madison', and 'Fielder', respectively) with the Forsythia intermedia PLR gene under the regulatory control of maize ubiquitin promoter. Of 24 putative transgenic wheat lines, we successfully obtained 3 transformants with the inserted ubiquitin-PLR gene as screened by PCR. Southern blot analysis further demonstrated that different copies of the PLR gene up to 5 were carried out in their genomes. Furthermore, a real-time PCR indicated approximately 17% increase of PLR gene expression over the control in 2 of the 3 positive transformants at T(0) generation. The levels of secoisolariciresinol diglucoside, a prominent lignan in wheat as determined by HPLC-MS, were found to be 2.2-times higher in one of the three positive transgenic sub-lines at T(2 )than that in the wild-type (117.9 +/- 4.5 vs. 52.9 +/- 19.8 mug/g, p <0.005). To the best of our knowledge, this is the first study that elevated lignan levels in a transgenic wheat line has been successfully achieved through genetic engineering of over-expressed PLR gene. Although future studies are needed for a stably expression and more efficient transformants, the new wheat line with significantly higher SDG contents obtained from this study may have potential application in providing additive health benefits for cancer prevention. 相似文献
9.
DT Luu D Marty-Mazars M Trick C Dumas P Heizmann 《Canadian Metallurgical Quarterly》1999,11(2):251-262
The adhesion of pollen grains to the stigma is the first step of pollination in flowering plants. During this step, stigmas discriminate between pollen grains that can and cannot be permitted to effect fertilization. This selection is operated by various constituents of the cell walls of both partners. Several genes structurally related to the self-incompatibility system that prevents self-pollination in Brassica spp are known to target their products into the stigma cell wall. We proposed previously that one of these genes, the one encoding the S locus glycoprotein (SLG)-like receptor 1 (SLR1), which is coexpressed with that encoding SLG, may participate in pollen-stigma adhesion. Here, we exploit a biomechanical assay to measure the pollen adhesion force and show that it is reduced both by transgenic suppression of SLR1 expression and by pretreatment of wild-type stigmas with anti-SLR1 antibodies, anti-SLG antibodies, or pollen coat-protein extracts. Our results indicate a common adhesive function for the SLR1 and SLG proteins in the pollination process. 相似文献
10.
Research on how older drivers react to natural challenges in the driving environment is relevant for both the research on mental workload and that on age-related compensation. Older adults (M age = 70.8 years) were tested in a driving simulator to assess the impact of three driving challenges: a visibility challenge (clear day, fog), a traffic density challenge (low density, high density) and a navigational challenge (participants followed the road to arrive at their destination, participants had to use signs and landmarks). The three challenge manipulations induced different compensatory speed adjustments. This complicated interpretation of the other measures of driving performance. As a result, speed adjustment indices were calculated for each condition and participant and composite measures of performance were created to correct for speed compensation. (These speed adjustment indices correlated with vision test scores and subscales of the Useful Field of View®.) When the composite measures of driving performance were analyzed, visibility × density × navigational challenge interactions emerged for hazard RT and SD of lane position. Effects were synergistic: the impact of the interaction of challenge variables was greater than the sum of independent effects. The directions of the effects varied depending on the performance measure in question though. For hazard RT, the combined effects of high-density traffic and navigational challenge were more deleterious in good visibility conditions than in fog. For or SD of lane position, the opposite pattern emerged: combined effects of high-density traffic and navigational challenge were more deleterious in fog than in clear weather. This suggests different aspects of driving performance tap different resources. 相似文献