Marina Stamenkovic´-Radak

University of Belgrade, Beograd, Central Serbia, Serbia

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Publications (3)2.98 Total impact

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    ABSTRACT: J Oral Pathol Med (2012) Background:  Genetic polymorphisms of vitamin D receptor gene (VDR) and genes involved in vitamin D metabolism pathway, CYP27B1 and CYP24B1, may affect individual susceptibility to oral squamous cell carcinoma. The purpose of this study was to evaluate the associations between VDR, CYP27B1 and CYP24A1 gene polymorphisms with oral cancer risk and survival. Methods:  Study cohort consisted of 110 patients with oral cancer and 122 healthy controls. The genotypes of the analysed genes were determined by PCR-RFLP or real-time PCR method. Results:  The significant decrease of oral cancer risk was observed in individuals with heterozygote genotype of CYP24A1 gene (rs2296241) (odds ratio 0.281, P = 0.000) in comparison with wild type. Patients with VDR FokI ff wild type genotype had significantly worse overall survival (P = 0.012, log rank) compared with heterozygous and mutated genotype combined. A stratified analysis by the lymph node involvement and tumour stage showed that ff is associated with poor survival in groups with and without lymph node involvement (P = 0.025, P = 0.040, respectively) and in stage III tumours (P = 0.026). Multivariate Cox's regression analysis revealed that VDR FokI could be considered an independent prognostic factor. Conclusion:  Our findings indicate that CYP24A1 gene polymorphism might have an influence on the susceptibility to oral cancer. VDR FokI polymorphism was associated with worse survival and could be considered as an independent prognostic marker.
    Journal of Oral Pathology and Medicine 05/2012; · 2.06 Impact Factor
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    ABSTRACT: Background: Natural environments fluctuate and all organisms experience some degree of environmental variance. Global climate models predict increasing environmental variance in the future. Yet we do not fully understand how environmental variation affects performance traits. Questions: Does temperature fluctuation during development affect adult size and wing shape in Drosophila melanogaster? If so, are the effects predictable? Do they depend on heterozygosity? Do fluctuations in developmental temperature affect adult physiological performance at high temperature? Methods: We tested the effect of one fluctuating (21C/29C) and several constant (21C, 23C, 25C, 27C, 29C) developmental temperature regimes on three wing morphometric traits (wing length, wing width, and wing shape) in an experiment using three inbred lines of D. melanogaster and their first-generation hybrids. We also tested the effect of fluctuating and constant developmental temperature on adult locomotor performance at several high and stressful test temperatures (32C, 34C, 36C, 38C, 40C). Results: Performance mostly declined if the flies were reared under the fluctuating temperature regime versus the constant temperature regime with the same mean (25C). Heterozygosity level also affected the traits investigated, with crossbreds usually having higher trait values. Crossbred genotypes compared across constant temperatures also showed greater plasticity in wing aspect. Conclusion: The widespread use of constant developmental temperatures in laboratory experiments may lead to overestimation of performance.
    Evolutionary ecology research 01/2012; 14:803-819. · 0.92 Impact Factor
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    ABSTRACT: Interspecies hybridization is expected to cause developmental instability (DI) as a consequence of outbreeding depression and genomic stress. The variability of fluctuating asymmetry (FA) of bilaterally symmetrical organs can accompany such stress conditions and change from parental individuals to hybrids. The aims of the present study were to estimate, under laboratory conditions, the degree of prezygotic reproductive isolation among three sibling Drosophila species, D. simulans, D. mauritiana and D. Melanogaster and to estimate the effects of interspecies hybridization on wing FA. The results show that D. mauritiana females are the most discriminating toward males from other species, whereas D. simulans females are the least discriminating and successfully give progeny of both sexes with both other species. D. melanogaster females give only female progeny with males of the other two species. Interspecies hybridization changes DI, but it is species-, sex-, and trait-specific. Our data support the heterozygosity hypothesis only in the case of the significant decrease of FA in wing width of female hybrids obtained from the D. simulans x D. melanogaster cross. Most of the obtained hybrids in our experiments show increases in FA due to disturbed coadaptive inter-allelic balances within the genome of each species, which is in favour of the coadaptation hypothesis.
    01/2009;