A variety of studies have evaluated the associations between polymorphisms in the promoter regions of the hMLH1 and cancer risk. However, the results remain inconclusive. To better understand the roles of the hMLH1 polymorphisms and cancer risk, we conducted a comprehensive meta-analysis to investigate the association between the hMLH1 − 93G/A and 1151T/A (Val384Asp) polymorphisms and cancer risk in Asian population.
Methods
We performed a meta-analysis by conducting searches of the published studies in Pub Med, CNKI, CBM, ISI web of knowledge and Google scholar search databases. Finally, 12 studies were included into our meta-analysis. Overall and subgroup analyses were performed. Odds ratio (OR) and 95% confidence interval (CI) were used to evaluate the associations between hMLH1 polymorphisms and cancer risk. Statistical analysis was performed with Review Manager 5.0.
Results
Twelve studies addressing two hMLH1 polymorphisms were analyzed among a total of 4128 cancer cases and 4678 controls. For hMLH1 − 93G/A, there was no evidence that the hMLH1 − 93G/A polymorphism was significantly associated with an increased cancer risk (P > 0.05) in Asian populations (heterozygote comparison: OR = 0.89 [95% CI (0.75, 1.060)] P = 0.20; dominant model comparison: OR = 0.98 [95% CI (0.83, 1.15)] P = 0.79). In subgroup analysis based on cancer types and the sources of control, no associations were found in colorectal cancer, gastric cancer and “other cancers” under the any gene model except for lung cancer (recessive model comparison: OR = 1.69 [95% CI (1.30, 2.19)] P < 0.0001). For hMLH1 1151T/A, the polymorphism significantly associated with an increased cancer risk in Asians: OR = 1.88 [95% CI (1.49, 2.25)], P < 0.0001, and OR = 1.87 [95% CI (1.49, 2.25)], P < 0.0001.
Conclusions
Our investigations demonstrated that the hMLH1 − 93G/A polymorphism is not a candidate for susceptibility to overall cancers, and that the hMLH1 1151T/A polymorphism is significantly associated with higher cancer risk in Asian populations. Further studies with large sample size for hMLH1 should be conducted. 相似文献
Sun light energy is used by plants to trigger their growth and development. However, an increase of UV-B light may lead to DNA damage. DNA photolyases are enzymes that repair the cyclobutane pyridine dimer (CPD) and 6–4 photoproduct lesions formed through UV irradiation of DNA. Many aspects of the repair process are under intense scientific investigation but still poorly understood. Here we have computationally analysed DNA-photolyases using the resonant recognition model (RRM), a physico-mathematical approach based on digital signal processing methods. The RRM proposes that protein interactions represent the transfer of resonant electromagnetic energy between interacting molecules at the particular frequency. Within this study we have determined photolyases characteristic frequency, “hot spots” amino acids corresponding to the functional mutations and functional active/binding sites, and designed photolyase peptide analogous. A mutual relationship between photolyase and p53 tumour suppressor protein has also been investigated. The results obtained provide new insights into the structure–function relationships of photolyase protein family. 相似文献
AbstractSex differences in attitudes toward the use of animals have been reported in previous research. This study examines sex differences in the levels of, and the interrelations among, three potential antecedents of attitudes toward animal use: caring value orientation, pet care experience and attachment to pets. Path analysis showed that pet care experience, through attachment to pets, accounted for a significant portion of variance in animal use attitudes in both males and females. Caring value orientation was directly linked to animal use attitudes in females, but in males, caring value orientation affected attachment to pets, which in turn impacted on animal use attitudes. Results are discussed in terms of Gilligan's theory of socialization. 相似文献
Abstract This paper presents an approach and a software, BetaDock, to the docking problem by putting the priority on shape complementarity between a receptor and a ligand. The approach is based on the theory of the β-complex. Given the Voronoi diagram of the receptor whose topology is stored in the quasi-triangulation, the β-complex corresponding to water molecule is computed. Then, the boundary of the β-complex defines the β-shape which has the complete proximity information among all atoms on the receptor boundary. From the β-shape, we first compute pockets where the ligand may bind. Then, we quickly place the ligand within each pocket by solving the singular value decomposition problem and the assignment problem. Using the conformations of the ligands within the pockets as the initial solutions, we run the genetic algorithm to find the optimal solution for the docking problem. The performance of the proposed algorithm was verified through a benchmark test and showed that BetaDock is superior to a popular docking software AutoDock 4. 相似文献
Background: Large areas of heathland landscapes in Galicia, north-west Spain, have traditionally been extensively grazed by free-ranging cattle and wild ponies. Recently, a large reduction in the number of these larger herbivores has been observed, with unknown consequences for the habitat.
Aims: To evaluate the effects of grazing and herbivore density on plant diversity, community composition and vegetation structure of the endemic wet heathlands dominated by Erica mackayana in Galicia.
Methods: Field sampling of vascular plants, generalised linear models (GLMs), non-metric multidimensional distance scaling (NMDS).
Results: Grazed sites had significantly higher total and rare species richness and diversity than ungrazed sites. Higher densities of cattle resulted in lower numbers of rare species, while wild pony density had no effect on rare species richness. In grazed sites, vegetation was lower with greater variation in height, resulting in greater heterogeneity of the habitat. Precipitation and summer temperatures were related to plant diversity, mainly beta diversity. Soil organic matter negatively correlated with rare species.
Discussion: Grazing, mostly by wild ponies, was demonstrated to be positively related to plant diversity and vegetation structure. Lack of grazing or high cattle densities resulted in a negative effect on total and rare species richness and diversity. Future climate change may negatively affect heathland plant diversity. Galician wild ponies represent a unique case of sustainable management of a wild species and an invaluable cultural heritage. Moreover, they have a significant role in maintaining the endemic E. mackayana heathlands, what would justify specific conservation actions for these large herbivores. 相似文献
In territorial species, rivals investment in fights over territories may increase when the availability of suitable areas for defense is low. This should occur because low territory availability may increase the costs to maintain and acquire territories. Although such process occurs in small spatial scales (local scale), territory availability in larger scales (regional scale) may also affect fighting investment, as losers should incur additional dispersing costs to find new territories. In this study, we used males of the hilltopping butterfly Strymon mulucha to evaluate the hypothesis that males should invest more in territorial fights when the costs to find new territories are higher (both at local and at regional scale). We timed male–male contests for territories located in 12 hilltops and measured male density per territory in each hilltop (local scale). We also quantified the distance between hilltops containing suitable areas for territories (regional scale). Male–male contests lasted 21 s on average, and copulations did not occur during the observations. The duration of contests was unrelated to the male density per territory or to the distance among hilltops, indicating that the investment in fights was unaffected by the availability of territorial sites, independent of the spatial scale. As male–male contests in S. mulucha are longer than the mean contest duration in other butterfly species and mating is extremely rare, we suggest that the value of each territory may be high enough to favor males that always invest as much as possible in contests. 相似文献