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排序方式: 共有218条查询结果,搜索用时 304 毫秒
71.
Maryam Rahimi Shima Fayaz Armaghan Fard-Esfahani Mohammad Hossein Modarressi Seyed Mohammad Akrami Pezhman Fard-Esfahani 《Iranian Biomedical Journal》2012,16(4):218-222
Background
The aim of this study was to understand any association between differentiated thyroid carcinoma (DTC) and Ile3434Thr XRCC7 gene polymorphism (GenBank accession number: rs7830743). DTC is the most prevalent thyroid neoplasm, which includes papillary and follicular cell carcinoma. XRCC7 gene encodes a protein that functions in non-homologous end joining DNA repair pathway. Non-synonymous polymorphisms in this gene may alter DNA repair capacity of the cell and change the risk of developing cancers.Methods
DTC patients (n = 173) and cancer free individuals (n = 204) were enrolled in a case-control study. The Ile3434Thr polymorphic alleles were discriminated by using amplification refractory mutation system-PCR method. The frequencies of this single nucleotide polymorphism in case and control groups were compared. Also, risk ratio for developing DTC in dichotomized genotypes was estimated by multivariate logistic regression analysis.Results
Dichotomized genotypes into those with and without the 3434Thr allele showed that this allele was associated with DTC (OR [odd ratio]: 1.89, 95% confidence interval (CI) = 1.29-2.79, P<0.001). Also, TC genotype was significantly associated with increased risk of DTC (OR: 2.42, 95% CI = 1.55-3.81, P = 0.0001) in individuals carrying this genotype.Conclusion
Allele 3434Thr in XRCC7 gene might be associated with differentiated thyroid cancer risk. Further studies with larger samples are needed to verify these initial findings. Key Words: DNA repair enzymes, Thyroid neoplasms, Genetic polymorphism 相似文献72.
73.
Selenium (Se) is an essential element for human and livestock with antioxidant and anticancer characteristics. Although Se is not an essential element for plants, it has been reported that it can improve plant growth. This experiment was conducted at the Isfahan University of Technology in winter 2010. The experiment was factorial based on a completely randomized design (CRD) with four replications. Se was added to nutrient solution in four concentrations 2, 4, and 6 mg/L sodium selenite (Na2SeO3). Root volume, fresh and dry weights of shoots and roots, number and weight of fruits, chlorophyll content, and photosynthesis traits [photosynthesis rate, stomata internal carbon dioxide (CO2) concentration, stomata conductance] were measured. Results showed that Se increased root dry weight. Fresh and dry weights of shoot increased in the 2 mg/L Se treatment and decreased at the higher level of Se. Chlorophyll content and photosynthesis rate were not affected by Se. Stomata internal CO2 concentration and stomata conductance decreased by Se addition. Overall, Se at 2 mg/L application rate was effective in some physiological characteristics of cucumber. 相似文献
74.
There are inconsistent results for the association of Mycobacterium avium subspecies paratuberculosis (MAP) infection with production and reproduction in dairy cows. Determination of these associations in each region is essential
to encourage participation of dairy cattle producers in disease control programs. This study was conducted in Shiraz, southern
Iran, to quantify the association of subclinical MAP infection with 305-day milk production and calving interval in Iranian
Holsteins. A total of 21 dairy herds were selected for the study and in each herd, quarter milk samples were collected from
ten to 12 dairy cows for PCR analysis. Data about parity, calving interval, length of lactation period, total milk production
and 305-day milk production were also provided for each animal. Overall, 252 individual milk samples were collected. Herd-
and individual-level prevalence of MAP infection were 23.8% (95% CI, 6.2–41.4%) and 3.2% (95% CI, 1.3–5.1%), respectively
based on IS900 nested PCR. The results for 305-day milk production revealed a 248 kg reduction in positive cows compared with
negative ones (P = 0.009). When cows from positive herds were compared with cows from negative herds, a 335-kg reduction in 305-day milk production
(P = 0.005) and a 30-day increase in calving interval (P = 0.057) were observed in the former group. These findings support the previous results that paratuberculosis infection is
negatively associated with the performance of the animals. 相似文献
75.
Pegah Khosravi Maryam Jafarkhani Kermani Ghorban Ali Nematzadeh Mohammad Reza Bihamta Kazutomo Yokoya 《Euphytica》2008,160(2):267-275
Dinitroanilines represent a class of compounds that are widely used in herbicide formulations as they depolymerise plant microtubles,
causing chromosome doubling. The potential of microtubule depolymerising herbicides trifluralin, oryzalin, and amiprophosmethyl
(APM) for in vitro chromosome doubling of Rosa was studied. Five concentrations (0, 3, 6, 12 and 24 μM) and three exposure periods (12, 24 and 48 h) for each of the compounds
were compared. Oryzalin, trifluralin and APM were not significantly different in their ability to induce chromosome doubling
of R. hybrida cv Iceberg. At concentration of 6 μM and exposure period of 24 h, chromosome doubling of R. hybrida cv Iceberg was not significantly different with each of the polyplodising agents. At higher concentration (24 μM) and longer
exposure period (48 h), 66.7% and 62.5% chromosome doubling was achieved with APM and trifluralin, respectively. However,
the application of 6 μM oryzalin to R. persica (2n = 2x), R. hybrida cv Iceberg (2n = 3x) and R. hybrida cv Akito (2n = 4x), resulted in 60.0%, 6.3% and 0% chromosome doubling, respectively, which suggest that chromosome doubling is genotype dependent
and plants with lower ploidy level have a higher propensity for chromosome doubling. Flow cytometry results at 18 and 24 weeks
after herbicide treatment, indicated that the best time to test the treated plants was after 24 weeks. 相似文献
76.
77.
More accurate estimation of crop evapotranspiration(ET_c)in a regional scale has always been one of the most important challenges.Temporal and spatial monitoring of ET_(c )using satellite images can help to enhance accuracy of estimations.In this study,the(ET_c)_(rice) maps were produced by using statistical/experimental methods based on crop coefficient(K_c)maps derived from vegetation index(Ⅵ).K_c was estimated using four methods,including linear relationship between K_c and Ⅵ(K_c-Ⅵ),calibrated model of K_c-Ⅵ,linear relationship between K_(cb)(the basal crop coefficient)and Ⅵ(K_(cb)-Ⅵ),and calibrated model of K_(cb)-Ⅵ.The results showed that calibrated model of K_c-Ⅵ had a better performance compared to the other methods,with normalized root mean square errors(NRMSE),mean absolute error and root mean square error being 5.7%,0.05 mm/d and 0.06mm/d,respectively.(ET_c)_(rice) maps were produced by using calibrated model of K_c-Ⅵ and reference evapotranspiration(ET_0)from FAO Penman-Monteith method.The NRMSE was 21.3%for using FAO Penman-Monteith method.Therefore,calibrated K_c-Ⅵ model in combining with ET_0 based on the Landsat 7 ETM+images could be provided a good estimation of(ET_c)_(rice) in regional scale,and can be applied to estimate water requirement due to the free and facilitate access. 相似文献
78.
Maryam Fazlollahi Mohammadi Seyed Gholamali Jalali Theresa A. Theodose 《Scandinavian Journal of Forest Research》2017,32(1):80-90
We examined the variation in woody plant species composition, regeneration and biodiversity in relation to topographic heterogeneity, specifically catena shape (V and Λ) and slope position (summit, shoulder, back slope, foot slope and toe slope). All research took place at the TMU Experimental Forest Station, located in northern Iran. Two sets of replicated quadrats were established along transects that encompassed the different catena shapes and positions. We recorded the density, height, and canopy cover of all trees ≥12 cm diameter at breast height within 30 quadrats (400m2), as well as the density of all tree regenerations within 120 quadrats (4m2). In addition, three measurements of biodiversity were calculated for both mature trees and regenerations. Mature tree species composition varied greatly with catena shape and slope position, as did that of regenerating trees. Despite differences in species composition, the various measurements of biodiversity were consistent across the landscape for mature trees, whereas significant variation in evenness was detected for regenerating trees. We concluded that the broad matrix of environmental conditions occurring within this rugged mountainous area generates a variety of microhabitats, which in turn contributes to both the variation in species composition and the consistent biodiversity of these forests. 相似文献
79.
This experiment was conducted as a factorial based on complete randomized design (CRD) to study the effects of mycorrhiza inoculation density on cucumber cv. Super N3 irrigated with different salinity sodium chloride (NaCl) levels. Treatments were mycorrhiza inoculations; M1 (non mycorrhizal plant), M2 and M3 (mycorrhiza inoculations with 1000 and 2000 spores) and saline water was provided by S1, S2, S3, and S4 (control, 50, 75, and 100 mM NaCl) with 4 replications. The results showed that saline water reduced root, shoot, and fruit weights, and increased proline and electrolyte leakage. Photosynthesis rate, stomata and mesophyll conductance significantly decreased with increased NaCl concentrations. Mycorrhiza inoculation with 2000 spores increased fruit fresh and dry weights, proline and electrolyte leakage, and both mycorrhiza inoculations increased root and shoot dry weights, photosynthesis and stomata conductance. Root volume increased by mycorrhiza inoculation with 2000 spores under non-stress condition, and root length was stimulated by both mycorrhiza inoculations at all saline water levels. Fruit fresh and dry weights were enhanced by mycorrhiza inoculation with 1000 spores at all saline water levels. Photosynthesis rate was reduced by saline water stress and mycorrhiza inoculation stimulated photosynthesis rate. Mycorrhiza inoculation with 2000 spores increased transpiration under saline and non-saline conditions. Proline content of cucumber leaves increased under saline water application. Electrolyte leakage increased by saline water and mycorrhiza inoculation could not improve it. Both mycorrhiza inoculations (1000 and 2000 spores) at all salinity levels, and mycorrhiza inoculation with 1000 spores at 100 mM NaCl enhanced fruit weight, photosynthesis, and proline content of the cucumber leaves. 相似文献
80.
Background: Impaired DNA repair mechanism is one of the main causes of tumor genesis. Study of intrinsic radiosensitivity of cancer patients in a non-target tissue (e.g. peripheral blood) might show the extent of DNA repair deficiency of cells in affected individuals and might be used a predictor of cancer predisposition. Methods: Initial radiation-induced DNA damage (ratio of Tail DNA/Head DNA), dose-response curves and kinetics of DNA repair in leukocytes from healthy volunteers and prostate cancer patients were assessed using alkaline comet assay after exposure to 60Co gamma rays. Results: Results showed that higher levels of baseline and gamma rays induced DNA damage in leukocytes of prostate cancer cases than in controls. A similar dose response was obtained for both groups. After a repair time of 24 h following in vitro irradiation, samples from the healthy individuals showed no residual DNA damage in their leukocytes, whereas prostate cancer patients revealed more than 20%. Although similar initial radiosensitivity was observed for both groups, the repair kinetics of radiation induced DNA damage of leukocytes from prostate cancer cases and healthy subjects were statistically different. Conclusion: These results support the hypothesis that men affected by prostate cancer may have a constitutional genomic instability. Key Words: Leukocytes, DNA damage, Radiosensitivity, Prostate cancer, Comet assay 相似文献