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991.
T.?E.?SchmidEmail author L.?Canella P.?Kudejova F.?M.?Wagner A.?R?hrmoser E.?Schmid 《Radiation and environmental biophysics》2015,54(1):91-102
Provided that a selective accumulation of 10B-containing compounds is introduced in tumor cells, following irradiation by thermal neutrons produces high-LET alpha-particles (4He) and recoiling lithium-7 (7Li) nuclei emitted during the capture of thermalized neutrons (0.025 eV) from 10B. To estimate the biological effectiveness of this boron neutron capture [10B(n,α)7Li] reaction, the chromosome aberration assay and the flow cytometry apoptosis assay were applied. At the presence of the clinically used compounds BSH (sodium borocaptate) and BPA (p-boronophenylalanine), human lymphocytes were irradiated by sub-thermal neutrons. For analyzing chromosome aberrations, human lymphocytes were exposed to thermally equivalent neutron fluences of 1.82 × 1011 cm?2 or 7.30 × 1011 cm?2 (corresponding to thermal neutron doses of 0.062 and 0.248 Gy, respectively) in the presence of 0, 10, 20, and 30 ppm of BSH or BPA. Since the kerma coefficient of blood increased by 0.864 × 10?12 Gy cm2 per 10 ppm of 10B, the kerma coefficients in blood increase from 0.34 × 10?12 cm2 (blood without BSH or BPA) up to 2.93 × 10?12 Gy cm2 in the presence of 30 ppm of 10B. For the 10B(n, α)7Li reaction, linear dose–response relations for dicentrics with coefficients α = 0.0546 ± 0.0081 Gy?1 for BSH and α = 0.0654 ± 0.0075 Gy?1 for BPA were obtained at 0.062 Gy as well as α = 0.0985 ± 0.0284 Gy?1 for BSH and α = 0.1293 ± 0.0419 Gy?1 for BPA at 0.248 Gy. At both doses, the corresponding 10B(n, α)7Li reactions from BSH and BPA are not significantly different. A linear dose–response relation for dicentrics also was obtained for the induction of apoptosis by the 10B(n, α)7Li reaction at 0.248 Gy. The linear coefficients α = 0.0249 ± 0.0119 Gy?1 for BSH and α = 0.0334 ± 0.0064 Gy?1 for BPA are not significantly different. Independently of the applied thermal neutron doses of 0.062 Gy or 0.248 Gy, the 10B(n, α)7Li reaction from 30 ppm BSH or BPA induced an apparent RBE of about 2.2 for the production of dicentrics as compared to exposure to thermal neutrons alone. Since the apparent RBE value is defined as the product of the RBE of a thermal neutron dose alone times a boron localization factor which depends on the concentration of a 10B-containing compound, this localization factor determines the biological effectiveness of the 10B(n, α)7Li reaction. 相似文献
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Mohamad Navab Arnab Chattopadhyay Greg Hough David Meriwether Spencer I. Fogelman Alan C. Wagner Victor Grijalva Feng Su G. M. Anantharamaiah Lin H. Hwang Kym F. Faull Srinivasa T. Reddy Alan M. Fogelman 《Journal of lipid research》2015,56(4):871-887
We previously reported that i) a Western diet increased levels of unsaturated lysophosphatidic acid (LPA) in small intestine and plasma of LDL receptor null (LDLR−/−) mice, and ii) supplementing standard mouse chow with unsaturated (but not saturated) LPA produced dyslipidemia and inflammation. Here we report that supplementing chow with unsaturated (but not saturated) LPA resulted in aortic atherosclerosis, which was ameliorated by adding transgenic 6F tomatoes. Supplementing chow with lysophosphatidylcholine (LysoPC) 18:1 (but not LysoPC 18:0) resulted in dyslipidemia similar to that seen on adding LPA 18:1 to chow. PF8380 (a specific inhibitor of autotaxin) significantly ameliorated the LysoPC 18:1-induced dyslipidemia. Supplementing chow with LysoPC 18:1 dramatically increased the levels of unsaturated LPA species in small intestine, liver, and plasma, and the increase was significantly ameliorated by PF8380 indicating that the conversion of LysoPC 18:1 to LPA 18:1 was autotaxin dependent. Adding LysoPC 18:0 to chow increased levels of LPA 18:0 in small intestine, liver, and plasma but was not altered by PF8380 indicating that conversion of LysoPC 18:0 to LPA 18:0 was autotaxin independent. We conclude that i) intestinally derived unsaturated (but not saturated) LPA can cause atherosclerosis in LDLR−/− mice, and ii) autotaxin mediates the conversion of unsaturated (but not saturated) LysoPC to LPA. 相似文献
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Wagner D Hanwell HE Schnabl K Yazdanpanah M Kimball S Fu L Sidhom G Rousseau D Cole DE Vieth R 《The Journal of steroid biochemistry and molecular biology》2011,126(3-5):72-77
24,25-Dihydroxyvitamin D (24,25VD) is a major catabolite of 25-hydroxyvitamin D (25VD) metabolism, and may be physiologically active. Our objectives were to: (1) characterize the response of serum 24,25VD(3) to vitamin D(3) (VD(3)) supplementation; (2) test the hypothesis that a higher 24,25VD(3) to 25VD(3) ratio (24,25:25VD(3)) predicts 25VD(3) response. Serum samples (n=160) from wk 2 and wk 6 of a placebo-controlled, randomized clinical trial of VD(3) (28,000IU/wk) were analyzed for serum 24,25VD(3) and 25VD(3) by mass spectrometry. Serum 24,25VD(3) was highly correlated with 25VD(3) in placebo- and VD(3)-treated subjects at each time point (p<0.0001). At wk 2, the 24,25:25VD(3) ratio was lower with VD(3) than with placebo (p=0.035). From wk 2 to wk 6, the 24,25:25VD(3) ratio increased with the VD(3) supplement (p<0.001) but not with placebo, such that at wk 6 this ratio did not significantly differ between groups. After correcting for potential confounders, we found that 24,25:25VD(3) at wk 2 was inversely correlated to the 25VD(3) increment by wk 6 in the supplemented group (r=-0.32, p=0.02) but not the controls. There is a strong correlation between 24,25VD(3) and 25VD(3) that is only modestly affected by VD(3) supplementation. This indicates that the catabolism of 25VD(3) to 24,25VD(3) rises with increasing 25VD(3). Furthermore, the initial ratio of serum 24,25VD(3) to 25VD(3) predicted the increase in 25VD(3). The 24,25:25VD(3) ratio may therefore have clinical utility as a marker for VD(3) catabolism and a predictor of serum 25VD(3) response to VD(3) supplementation. 相似文献
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Lisheng Kong Patrick von Aderkas Stacey J. Owen Tia Wagner Suzanne R. Abrams 《Trees - Structure and Function》2011,25(6):1103-1110
In lodgepole pine (Pinus contorta Dougl. ex Loud. var. latifolia Engelm.), cone bud initiation within long-shoot buds varies according to genotype. We chose to study hormone profiles of
two genotypes that differed significantly in cone yield. Phytohormone profiles were established by high performance liquid
chromatography–electrospray ionization tandem mass spectrometry in multiple reaction monitoring mode with samples collected
from genotypes 299 and 233, the typically high and low cone producers. Generally, concentrations of trans-zeatin-O-glucoside were higher in genotype 299, whereas dihydrozeatin concentrations were higher in genotype 233. Both isopentenyl
adenine and isopentenyl adenosine were present at higher concentrations in genotype 233. The ratio of total quantifiable zeatin
(Z)-type cytokinins to isopentenyl (iP)-type cytokinins was approximately threefold higher in genotype 299 during female cone
bud differentiation. In genotype 299, ABA concentration was significantly lower than in genotype 233 on the first sampling
date, while the phaseic acid concentration was lower consistently throughout the period investigated. Dihydrophaseic acid
was present in low concentrations in most samples of genotype 233, but was not quantifiable in genotype 299. Our study reveals
that long-shoot buds of the high cone-producing genotype had higher ratios of Z-type cytokinins to iP-type cytokinins than
were found in the low cone-producing genotype. High cone-producing buds also contained less ABA, phaseic acid and dihydrophaseic
acid during female cone bud differentiation. 相似文献
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As part of a series of studies on new potential green high energy materials, we have calculated the structures and properties
of a series of nitro-substituted urea molecules. Our results indicate that nitrated urea molecules have specific enthalpies
of decomposition commensurate with current high energy materials. At the same time, they are all low in carbon, suggesting
an application as a “green” high energy material. 相似文献