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1.
The human lymphocyte micronucleus assay: a comparison between whole-blood and separated-lymphocyte cultures 总被引:3,自引:0,他引:3
The induction of micronuclei (MN) by vincristine, mitomycin C and cyclophosphamide was compared in purified lymphocytes and in whole-blood cultures. With both assays, cytokinesis was blocked by cytochalasin B and MN were only scored in binucleate cells. The data suggest that whole-blood cultures may be considered a better experimental condition for the detection of MN induced by chemicals in vitro. 相似文献
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C Crone J Frokjaer-Jensen JJ Friedman O Christensen 《The Journal of general physiology》1978,71(2):195-220
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Marine Pouget Sami Youssef Jérémy Migliore Marianick Juin Frédéric Médail Alex Baumel 《Annals of botany》2013,112(7):1409-1420
Background and Aims
Understanding the factors that shape variation in genetic diversity across the geographic ranges of species is an important challenge in the effort to conserve evolutionary processes sustaining biodiversity. The historical influences leading to a central–marginal organization of genetic diversity have been explored for species whose range is known to have expanded from refugia after glacial events. However, this question has rarely been addressed for Mediterranean endemic plants of azonal habitats such as rocky slopes or screes. In this context, this comprehensive study examined molecular and field data from Arenaria provincialis (Caryophyllaceae), a narrow endemic plant of south-eastern France.Methods
Across the whole geographic range, an investigation was made of whether high levels of abundance and genetic diversity (estimated from amplified fragment length polymorphism markers) are centrally distributed, to evaluate the relevance of the central–marginal hypothesis. Phylogeographic patterns inferred from chloroplast DNA (cpDNA) were used, applying Bayesian methods to test the influence of past biogeographic events. Multivariate analysis combining phylogeographic and ecological data was used to reveal the historical and ecological distinctiveness of populations.Key Results
Despite the narrow distribution of A. provincialis, a high level of nucleotide variation is found within cpDNA loci, supporting its persistence throughout the Pleistocene period. The area characterized by the highest genetic diversity is centrally located. Structured phylogeography and Bayesian factor analysis supported the hypothesis that the central area of the distribution was the source of both westward and eastward migrations, probably during arid periods of the Pleistocene, and more recently was a crossroads of backward migrations. By contrast, the two areas located today at the range limits are younger, have reduced genetic diversity and are marginal in the ecological gradients.Conclusions
This study highlights a case of strong population distinctiveness within a narrow range. Phylogeography sheds light on the historical role of the areas centrally situated in the distribution. The current range size and abundance patterns are not sufficient to predict the organization of genetic diversity. 相似文献9.
Fenech M Bonassi S Turner J Lando C Ceppi M Chang WP Holland N Kirsch-Volders M Zeiger E Bigatti MP Bolognesi C Cao J De Luca G Di Giorgio M Ferguson LR Fucic A Lima OG Hadjidekova VV Hrelia P Jaworska A Joksic G Krishnaja AP Lee TK Martelli A McKay MJ Migliore L Mirkova E Müller WU Odagiri Y Orsiere T Scarfì MR Silva MJ Sofuni T Surralles J Trenta G Vorobtsova I Vral A Zijno A Suralles J;HUman MicroNucleus project 《Mutation research》2003,534(1-2):45-64
One of the objectives of the HUman MicroNucleus (HUMN) project is to identify the methodological variables that have an important impact on micronucleus (MN) or micronucleated (MNed) cell frequencies measured in human lymphocytes using the cytokinesis-block micronucleus assay. In a previous study we had shown that the scoring criteria used were likely to be an important variable. To determine the extent of residual variation when laboratories scored cells from the same cultures using the same set of standard scoring criteria, an inter-laboratory slide-scoring exercise was performed among 34 laboratories from 21 countries with a total of 51 slide scorers involved. The results of this study show that even under these optimized conditions there is a great variation in the MN frequency or MNed cell frequency obtained by individual laboratories and scorers. All laboratories ranked correctly the MNed cell frequency in cells from cultures that were unirradiated, or exposed to 1 or 2Gy of gamma rays. The study also estimated that the intra-scorer median coefficient of variation for duplicate MNed cell frequency scores is 29% for unexposed cultures and 14 and 11% for cells exposed to 1 and 2Gy, respectively. These values can be used as a standard for quality or acceptability of data in future studies. Using a Poisson regression model it was estimated that radiation dose explained 67% of the variance, while staining method, cell sample, laboratory, and covariance explained 0.6, 0.3, 6.5, and 25.6% of the variance, respectively, leaving only 3.1% of the variance unexplained. As part of this exercise, nucleoplasmic bridges were also estimated by the laboratories; however, inexperience in the use of this biomarker of chromosome rearrangement was reflected in the much greater heterogeneity in the data and the unexplained variation estimated by the Poisson model. The results of these studies indicate clearly that even after standardizing culture and scoring conditions it will be necessary to calibrate scorers and laboratories if MN, MNed cell and nucleoplasmic bridge frequencies are to be reliably compared among laboratories and among populations. 相似文献
10.
Migliore S 《Medical anthropology quarterly》2001,15(1):100-125
The concept of "nerves" is an integral component of the language of distress found in a number of societies. Individuals, however, often extend its meaning well beyond the realm of suffering. In this article, I examine some Sicilian-Canadian uses of "nerves" from a Pirandellian perspective. This, I believe, gives us an insight into how people (1) make use of illness narratives to give meaning to their life experiences, and (2) attempt to influence the thought and behavior of significant others. In the process, I address the question how do we move away from anthropological definitions and explanations that tend to simplify or mask some of the rich complexities surrounding the meaning(s) of "folk" concepts? 相似文献