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Summary Chromosome aberrations in 20 lymphocytes of 20 patients with testicular germ cell tumors (TGCT) treated with surgery alone were compared with those of 20 cells from 20 healthy controls using standard G-banding technique. No increase in structural aberrations was found in the cancer group. An unexpected finding was that of more cells with losses of chromosomes being present in the control group. These losses predominantly affected small chromosomes in the control group, whereas the pattern of chromosome loss was different in the cancer group. The literature claiming increased chromosome instability in TGCT patients is reviewed. Point estimates and 95% confidence intervals to exclude such a hypothesis based on our results were calculated.  相似文献   

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Increased cooperation in groups that are allowed to communicate (engage in "cheap talk") has been attributed to reputation-building and to cultural norms or culturally normal behavior. We tested these two theories by exposing groups of undergraduates to a public-goods social dilemma. Five groups were permitted to communicate via anonymous written messages that were read aloud. The groups with messaging contributed substantially more to the common good than the groups without messaging. Because the messages were anonymous, their efficacy cannot be explained by effects on reputation. Instead, the results point to the participants' histories of giving and receiving exhortations to cooperate - i.e., to culturally normal behavior (cultural norms).  相似文献   

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Information on the existence of the interspecific constitutional polymorphism in rabbits of chinchilla [correction of "Shinshilla"] and "white giant" to ophthalmic hypertension and glaucoma in abundance of catecholamine was presented. Experiences show that rabbits of chinchilla [correction of "shinshilla"] under the abundance of catecholamine in difference of "albino" rabbits do not have glaucoma. Albinos are not protected from the abundance of POL under the influence of catecholamine.  相似文献   

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Insight into the genetic basis of malaria resistance is crucial for understanding the consequences of this parasite group on animal populations. Here, we analyse the relationship between genotypic variation at 11 highly variable microsatellite loci and prevalence of three different lineages of avian malaria, two Plasmodium (RTSR1, LK6) and one Haemoproteus (LK2), in a wild population of the endangered lesser kestrel (Falco naumanni). Although we used a large sample size (584 typed individuals), we did not find any significant association between the prevalence of the studied parasite lineages and individual genetic diversity. Although our data set is large, the 11 neutral markers typed may have had low power to detect such association, in part because of the low parasite prevalence observed (less than 5% of infected birds). However, the fact that we have detected previous correlations between genetic diversity and other traits (ectoparasitism risk, fecundity) in the study population using the same panel of neutral markers and lower sample sizes suggests that other factors could underlie the absence of such a similar correlation with avian malaria. Differences in the genetics of the studied traits and in their particular basis of inbreeding depression (dominance vs. overdominance) may have led to malaria prevalence, but not other traits, being uncoupled with individual genetic diversity. Also, we cannot discard the possibility that the absence of association was a consequence of a low pathogenic effect of these particular malaria lineages on our lesser kestrel population, and thus we should not expect the evolution of genetic resistance against these parasites.  相似文献   

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Boots AW  Bast A  Haenen GR 《FEBS letters》2005,579(3):677-682
Quercetin is one of the most studied alimentary antioxidants. During its antioxidant activity, quercetin becomes oxidized into its ortho-quinone/quinone methide, denoted as QQ. QQ is toxic since it is highly reactive towards thiols. DT-diaphorase (NQO1) might protect against QQ toxicity by reducing QQ to quercetin. However, conflicting data have been reported. The aim of the present study is to elucidate the role of DT-diaphorase in the protection against QQ-mediated thiol reactivity. It was found that QQ is indeed a substrate for DT-diaphorase. However, QQ reacted much faster with glutathione or protein thiols than with DT-diaphorase in experiments with isolated compounds as well as with human liver cytosol or blood plasma. This indicates that DT-diaphorase has no role in the protection against QQ.  相似文献   

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Immune defenses of insects show either broad reactions or specificity and durability of induced protection against attacking parasites and pathogens. In this study, we tested whether encapsulation response against nylon monofilament increases between two attempts of activation of immune system in mealworm beetles Tenebrio molitor, and whether previous exposure to nylon monofilament may also increase protection against an entomopathogenic fungus. We found that survival of beetles subjected to immune activation by nylon implant and subsequent fungal exposure a week later was significantly higher than survival of beetles which had been subjected to fimgal infection only. This result suggests that previous immune activation by the nylon implant may be considered as broad spectrum "immune priming" which helps to fight not only the same intruder but also other parasites.  相似文献   

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Immune defenses of insects show either broad reactions or specificity and durability of induced protection against attacking parasites and pathogens. In this study, we tested whether encapsulation response against nylon monofilament increases between two attempts of activation of immune system in mealworm beetles Tenebrio molitor, and whether previous exposure to nylon monofilament may also increase protection against an entomopathogenic fungus. We found that survival of beetles subjected to immune activation by nylon implant and subsequent fungal exposure a week later was significantly higher than survival of beetles which had been subjected to fungal infection only. This result suggests that previous immune activation by the nylon implant may be considered as broad spectrum “immune priming” which helps to fight not only the same intruder but also other parasites.  相似文献   

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Capsule: A multi-element index is developed to help support decisions with respect to the establishment and review of national networks of European Union (EU) Special Protection Areas (SPAs).

Aims: To develop an index based on biological criteria which can be used to assess the sufficiency of protected area network coverage for national populations of individual bird species.

Methods: A Site Provision Index (SPI) was derived from data on species’ national and international distribution, population size, habitat use and site-fidelity. It was tested against the results of past UK policy and independent expert judgement.

Results: Index values were calculated for all regularly occurring UK birds for which the EU Birds Directive indicates that SPA provision should be considered. Index values and expert opinion on the percentage of populations of species expected to be found in a national network of protected areas were highly correlated. Indices also strongly correlated with existing provision of SPA protection for populations. Residuals from this regression relationship highlight objectively those species where consideration of further SPA provision may be necessary.

Conclusion: The SPI can provide a decision-support tool, through a form of gap analysis, to help identify where there is a significant difference between current protected area provision for a species and the level of provision that might be expected relative to other species with similar distribution and ecology.  相似文献   


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Human erythrocytes are used as a test system to study the cryoprotective effects of two pluronics (the ethylene oxide-polypropylene glycols) of different molecular weights: F68, (average molecular weight 8350 daltons) and F108 (average molecular weight 14,000 daltons). Combinations of F68 and F108 with dimethylsulfoxide (DMSO) are studied, as well as combinations of F68 and F108. Cooling and thawing rates (defined over the range ?15 to ?60 °C) are ?12.5, ?350, ?1800, and +300 °C/min. Pluronic F68 offers a similar protection to that afforded by DMSO and glycerol but it is more effective than DMSO at the higher cooling rates. F68 is considerably more effective than F108—the latter requires twice the concentration (i.e., 20% w/v) to provide 90% protection to whole blood in the presence of acid-citrate dextrose. Cryoprotection afforded by combinations of the pluronic F68 and DMSO is additive under certain circumstances. For a given total percentage of additive, the protection is enhanced if the DMSO dominates, and decreased if the pluronic dominates, when compared to the same amount of the individual additives. High molecular-weight pluronic solutions are thus shown to be cryoprotective to human erythrocytes and similar in their behaviour to the low molecular-weight DMSO and glycerol; however, the shapes of the curves (protection vs. percentage of additive) are sufficiently different to be of theoretical interest in the study of freeze-thaw membrane damage, particularly as a change in the normal protective response is apparent for certain combinations of a high and low molecular-weight additive.  相似文献   

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