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31.
Monocrotaline (MCT) is a hepatotoxic pyrrolizidine alkaloid that is derived from plants; exposure may occur by consumption of contaminated grains, herbal teas and medicines. MCT can cause liver damage. We investigated the antioxidant effects of selenium (Se) and vitamin E against the toxic effects of MCT. Female Wistar albino rats were divided into four groups: a control group, an MCT group, an MCT + Se group, and an MCT + vitamin E group. Liver tissues were harvested, fixed, processed to paraffin and sections were cut. Anti-von Willebrand factor (vWF) immunohistochemistry, terminal deoxynucleotidyl transferase dUTP nick end-labeling (TUNEL), and hematoxylin and eosin staining were performed. Serum and liver tissue glutathione (GSH), catalase (CAT), and glutathione peroxidase (GPx) levels were measured. Histopathological and TUNEL data showed significantly increased liver damage in the MCT group compared to controls. Histopathological and TUNEL staining indicated significant improvements in the MCT + vitamin E and MCT + Se groups compared to the MCT group. MCT significantly reduced the serum GSH level and GPx activity, and liver GPx activity. Biochemical data indicated a significant improvement in serum GSH level in the MCT + vitamin E group compared to the MCT group. We suggest that vitamin E and Se afford limited protection against MCT hepatotoxicity.  相似文献   
32.
A series of 6-beta-arylamidomorphines was synthesized and biologically evaluated. Various aryl substituents were introduced into the arylamidomorphines to examine substituent structure-activity relationships. Competition binding assays showed that compounds 10a-h bound to the mu opioid receptor with high affinity (0.2-0.6 nM). Functional assays showed that compounds 10a-h acted as full mu opioid receptor agonists. The ED(50) of compound 10e.HCl as an analgesic was 12.6 mg/kg in the tail flick latency test in the rat.  相似文献   
33.
Treatment with erythropoietin is highly effective and beneficial if given with care. In view of its cost, however, it is essential to exclude and treat other causes of anaemia before considering using this hormone. After treatment is started the important points for success are regular review of iron availability state combined with a slow correction of the anaemia. Failure of response requires a thorough search for a possible cause, which should be corrected before considering an increased dose of the hormone. Regular monitoring for potential complications, particularly a rise in blood pressure, is required.  相似文献   
34.
A retrospective survey was made of 305 patients with proved urinary calculi. When those patients with a solitary stone were compared with those with multiple stones no diagnostically helpful difference was noted in the prevalence of abnormal serum or urine biochemistry, urinary infection, or anatomical abnormality of the urinary tract. The same was true of the stone composition and the need for surgery. It seems that neither routine radiological examination nor regular follow-up is likely to help identify patients whose stones are going to recur.  相似文献   
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The accuracy of genomic selection depends on the relatedness between the members of the set in which marker effects are estimated based on evaluation data and the types for which performance is predicted. Here, we investigate the impact of relatedness on the performance of marker-assisted selection for fungal disease resistance in hybrid wheat. A large and diverse mapping population of 1739 elite European winter wheat inbred lines and hybrids was evaluated for powdery mildew, leaf rust and stripe rust resistance in multi-location field trials and fingerprinted with 9 k and 90 k SNP arrays. Comparison of the accuracies of prediction achieved with data sets from the two marker arrays revealed a crucial role for a sufficiently high marker density in genome-wide association mapping. Cross-validation studies using test sets with varying degrees of relationship to the corresponding estimation sets revealed that close relatedness leads to a substantial increase in the proportion of total genotypic variance explained by the identified QTL and consequently to an overoptimistic judgment of the precision of marker-assisted selection.  相似文献   
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Synthesis Prediction and management of species responses to climate change is an urgent but relatively young research field. Therefore, climate change ecology must by necessity borrow from other fields. Invasion ecology is particularly well‐suited to informing climate change ecology because both invasion ecology and climate change ecology address the trajectories of rapidly changing novel systems. Here we outline the broad range of active research questions in climate change ecology where research from invasion ecology can stimulate advances. We present ideas for how concepts, case‐studies and methodology from invasion ecology can be adapted to improve prediction and management of species responses to climate change. A major challenge in this era of rapid climate change is to predict changes in species distributions and their impacts on ecosystems, and, if necessary, to recommend management strategies for maintenance of biodiversity or ecosystem services. Biological invasions, studied in most biomes of the world, can provide useful analogs for some of the ecological consequences of species distribution shifts in response to climate change. Invasions illustrate the adaptive and interactive responses that can occur when species are confronted with new environmental conditions. Invasion ecology complements climate change research and provides insights into the following questions: 1) how will species distributions respond to climate change? 2) how will species movement affect recipient ecosystems? And 3) should we, and if so how can we, manage species and ecosystems in the face of climate change? Invasion ecology demonstrates that a trait‐based approach can help to predict spread speeds and impacts on ecosystems, and has the potential to predict climate change impacts on species ranges and recipient ecosystems. However, there is a need to analyse traits in the context of life‐history and demography, the stage in the colonisation process (e.g. spread, establishment or impact), the distribution of suitable habitats in the landscape, and the novel abiotic and biotic conditions under which those traits are expressed. As is the case with climate change, invasion ecology is embedded within complex societal goals. Both disciplines converge on similar questions of ‘when to intervene?‘ and ‘what to do?‘ which call for a better understanding of the ecological processes and social values associated with changing ecosystems.  相似文献   
39.
Roy, B. D., M. A. Tarnopolsky, J. D. MacDougall, J. Fowles,and K. E. Yarasheski. Effect of glucose supplement timing onprotein metabolism after resistance training. J. Appl.Physiol. 82(6): 1882-1888, 1997.We determinedthe effect of the timing of glucose supplementation on fractionalmuscle protein synthetic rate (FSR), urinary urea excretion, and wholebody and myofibrillar protein degradation after resistance exercise.Eight healthy men performed unilateral knee extensor exercise (8 sets/~10 repetitions/~85% of 1 single maximal repetition). Theyreceived a carbohydrate (CHO) supplement (1 g/kg) or placebo (Pl)immediately (t = 0 h) and 1 h(t = +1 h) postexercise. FSR wasdetermined for exercised (Ex) and control (Con) limbs by incrementalL-[1-13C]leucineenrichment into the vastus lateralis over ~10 h postexercise. Insulinwas greater (P < 0.01) at 0.5, 0.75, 1.25, 1.5, 1.75, and 2 h, and glucose was greater(P < 0.05) at 0.5 and 0.75 h for CHO compared with Pl condition. FSR was 36.1% greater in the CHO/Ex leg than in the CHO/Con leg(P = not significant) and6.3% greater in the Pl/Ex leg than in the Pl/Con leg(P = not significant). 3-Methylhistidine excretion was lower in the CHO (110.43 ± 3.62 µmol/g creatinine) than Pl condition (120.14 ± 5.82, P < 0.05) as was urinary ureanitrogen (8.60 ± 0.66 vs. 12.28 ± 1.84 g/g creatinine,P < 0.05). This suggests that CHOsupplementation (1 g/kg) immediately and 1 h after resistance exercisecan decrease myofibrillar protein breakdown and urinary urea excretion,resulting in a more positive body protein balance.

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40.
Single-copy nuclear DNAs (scnDNAs) of eight species of arvicoline and six species of murine rodents were compared using DNA-DNA hybridization. The branching pattern derived from the DNA comparisons is congruent with the fossil evidence and supported by comparative biochemical, chromosomal, and morphological studies. The recently improved fossil record for these lineages provides seven approximate divergence dates, which were used to calibrate the DNA-hybridization data. The average rate of scnDNA divergence was estimated as 2.5%/Myr. This is approximately 10 times the rate in the hominoid primates. These results agree with previous reports of accelerated DNA evolution in muroid rodents and extend the DNA-DNA hybridization data set of Brownell.   相似文献   
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