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排序方式: 共有135条查询结果,搜索用时 31 毫秒
81.
82.
Mohammad Taghi Bahreyni Toossi Malihe Abdollahi Mahdi Ghorbani 《Reports of Practical Oncology and Radiotherapy》2011,16(1):10-13
Background
As a routine method for stepping source simulation, a Monte Carlo program is run according to the number of steps and then the summation of dose from each run is taken to obtain total dose distribution. This method is time consuming.Aim
As an alternative method, a matrix shift based technique was applied to simulate a stepping source for brachytherapy.Materials and methods
The stepping source of GZP6 brachytherapy unit was simulated. In a matrix shift method, it is assumed that a radiation source is stationary and instead the data matrix is shifted based on the number of steps. In this study, by running MCNPX program for one point and calculation of the dose matrix using the matrix shift method, the isodose curves for the esophageal cancer tumor lengths of 4 and 6 cm were obtained and compared with the isodose curves obtained by running MCNPX programs in each step position separately (15 and 23 steps for esophageal cancer tumor lengths of 4 and 6 cm, respectively).Results
The difference between the two dose matrixes for the stepping and matrix shift methods based on the average dose differences are 3.85 × 10−4 Gy and 5.19 × 10−4 Gy for treatment length of 4 cm and 6 cm, respectively. Dose differences are insignificant and these two methods are equally valid.Conclusions
The matrix shift method presented in this study can be used for calculation of dose distribution for a brachytherapy stepping source as a quicker tool compared to other routine Monte Carlo based methods. 相似文献83.
Etminani-Esfahani M Khalili H Jafari S Abdollahi A Dashti-Khavidaki S 《BMC research notes》2012,5(1):204
ABSTRACT: BACKGROUND: It was reported that antiretroviral drugs such as efavirenz can increase the catabolism of vitamin D in HIV infected individuals. We have not found any study that evaluated effects of vitamin D supplementation on the bone specific biomarkers in HIV positive patients under treatment with antiretroviral regimen containing efavirenz. FINDINGS: Vitamin D deficiency was detected in 88.4 % of included patients. Baseline osteocalcin, but not collagen telopeptidase, serum levels were lower than normal range in all of these individuals. Both bone biomarkers' concentrations increased significantly (p < 0.001 for both of them) after supplementation of vitamin D and it was more predominant for osteocalcin. CONCLUSION: In the HIV-infected patients under treatment with efavirenz, vitamin D deficiency is prevalent. After supplementation with single dose of 300,000 IU vitamin D in this population, the activation of osteoblasts and osteoclasts stimulates bone formation and resorption respectively with favorable bone formation without any adverse event. Significant percent of HIV infected individuals are vitamin d deficient that could benefit from vitamin D supplementation. 相似文献
84.
Moravej A Rasouli M Kalani M Asaei S Kiany S Najafipour S Koohpayeh A Abdollahi A 《Molecular biology reports》2012,39(6):6907-6914
Lymphotoxin-α (LT-α) and interleukin-1beta (IL-1β) are proinflammatory cytokines playing important roles in immunity against
Leishmania infection and the outcome of the disease. As cytokine productions are under the genetic control, this study tried to find
any probable relationship between these cytokine gene polymorphisms and the susceptibility to visceral leishmaniasis in Iranian
pediatric patients. Ninety-five pediatric patients involved with visceral leishmaniasis and 128 non-relative healthy people,
from the same area as the patients, were genotyped for LT-α (+252A/G) and IL-1β (+3953T/C and −511T/C) gene polymorphisms
using polymerase chain reaction-restriction fragment length polymorphism (PCR–RFLP). There was not found any significant differences
in allele and genotype frequencies of LT-α (+252A/G) and IL-1β (+3953) among the study groups. However, the frequency of IL-1β
−511TT genotype was higher in the controls (P = 0.0004) while the frequency of IL-1β −511CC genotype and C allele were higher in the patients (P = 0.008 and P = 0.00006, respectively). Furthermore, IL-1β CC (−511/+3953) haplotype was more frequent in VL patients compared with the
controls (P = 0.0002) and the distribution of TT haplotype was higher in the controls compared with the patients (P = 0.003). In conclusion, based on the results, IL-1β −511C allele, CC genotype and CC (−511/+3953) haplotype could be considered
as the susceptibility factors for visceral leishmaniasis while IL-1β −511TT genotype, T allele and TT haplotype (−511/+3953)
might be counted as the influential factors for resistance to the disease. 相似文献
85.
86.
Abdollahi M Mostafalou S Pournourmohammadi S Shadnia S 《Comparative biochemistry and physiology. Toxicology & pharmacology : CBP》2004,137(1):29-34
The aim of this study was to examine whether malathion, a commonly used organophosphate (OP), might induce oxidative stress and cholinesterase (ChE) depression in saliva and plasma in rats following subchronic exposure mimicking human exposure. Malathion was administered orally at doses of 100, 500 and 1500 ppm for 4 weeks. Oxidative stress was determined by measuring the malondialdehyde concentration, the end product of lipid peroxidation, and assessing total antioxidant power. Four weeks oral administration of malathion at doses of 100 ppm, 500 ppm and 1500 ppm depressed plasma ChE activity to 45% (P<0.01), 48% (P<0.01) and 41% (P<0.01) of control, respectively. Malathion at doses of 100 ppm, 500 ppm and 1500 ppm depressed saliva ChE activity to 73% (P<0.01), 75% (P<0.01) and 78% (P<0.01) of control, respectively. Malathion at doses of 100 ppm, 500 ppm and 1500 ppm increased plasma antioxidant power by 33% (P<0.01), 59% (P<0.01) and 118% (P<0.01) of control, respectively. Malathion did not change saliva antioxidant power. Malathion at doses of 100 ppm, 500 ppm and 1500 ppm increased plasma thiobarbituric acid reactive substances (TBARS) by 61% (P<0.01), 69% (P<0.01) and 63% (P<0.01) of control, respectively. Malathion at doses of 500 ppm and 1500 ppm increased saliva TBARS by 19% (P<0.01) and 22% (P<0.01) of control, respectively. Malathion (100 ppm) did not change saliva TBARS level. We concluded that in OP subchronic exposure, depression of ChE is accompanied by induction of oxidative stress that might be beneficial in monitoring OP toxicity. 相似文献
87.
Endostatin's antiangiogenic signaling network 总被引:16,自引:0,他引:16
Abdollahi A Hahnfeldt P Maercker C Gröne HJ Debus J Ansorge W Folkman J Hlatky L Huber PE 《Molecular cell》2004,13(5):649-663
It is here demonstrated that the set of gene expressions underlying the angiogenic balance in tissues can be molecularly reset en masse by a single protein. Using genome-wide expression profiling, coupled with RT-PCR and phosphorylation analysis, we show that the endogenous angiogenesis inhibitor endostatin downregulates many signaling pathways in human microvascular endothelium associated with proangiogenic activity. Simultaneously, endostatin is found to upregulate many antiangiogenic genes. The result is a unique alignment between the direction of gene regulation and angiogenic status. Profiling further reveals the regulation of genes not heretofore associated with angiogenesis. Our analysis of coregulated genes shows complex interpathway communications in an intricate signaling network that both recapitulates and extends on current understanding of the angiogenic process. More generally, insights into the nature of genetic networking from the cell biologic and therapeutic perspectives are revealed. 相似文献
88.
Due to recalcitrant nature of chickpea (Cicer arietinum L.) to androgenesis, the production of double haploid plants has been only reported by Grewal et al. (Plant Cell Rep 28:1289–1299, 2009) using some physical stresses such as anther centrifugation and electrical shock. In the present study, we successfully obtained haploid plants from cultured anthers of two chickpea cultivars, Bivanij and Arman, using high 2,4-D and silver nitrate containing media without applying of these time and labor consuming stresses. For induction of androgenesis, different concentrations of 2, 4-D (0, 2, 5 and 10 mg/l) and silver nitrate (0, 5, 10, 15, 25 and 50 mg/l) were used in embryo development medium. In Bivanij cultivar, anther induction medium containing 10 mg/l 2,4-D and 15 mg/l silver nitrate produced the highest number of embryos (0.188) and regenerated plants (0.1) per each cultured anther, while the highest frequencies of embryos (0.1) and regenerated plants (0.075 and 0.063) were obtained from Arman cultivar when 10 mg/l 2,4-D was combined with 15 and 50 mg/l silver nitrate in anther culture medium, respectively. In second part of this study, different cold (4 °C for 4 and 7 days) and heat (30 °C for 10 days, 32 °C for 2 days and 35 °C for 8 h) pretreatments were applied on cultured anthers of Bivanij cultivar. Incubation of cultured anthers at 32 °C for 2 days significantly enhanced the rate of embryo formation up to 0.222 embryos per each anther, while the highest number of regenerated plants/anther (0.0332) was obtained when cold treated anthers at 4 °C for 7 days incubated at 30 °C for 10 days. Taken together, these results provide a good basis for large-scale generation of DH plants in this important legume species. 相似文献
89.
Abdollahi Mohammad Reza Kianersi Farzad Moosavi Sayyed Saeed Dastan Dara Asadi Sepideh 《Journal of Plant Growth Regulation》2023,42(2):759-770
Journal of Plant Growth Regulation - Fennel (Foeniculum vulgare Mill.), a medicinal plant from the Apiaceae, is used in traditional medicine. For the first time in F. vulgare, partial cDNA of two... 相似文献
90.