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61.
A field-scale three-dimensional numerical flow and transport model was applied to simulate the fate and transport of benzene, toluene, ethylbenzene, and xylenes (BTEX) from six source zones of light non-aqueous-phase liquids (LNAPLs). A number of scenarios were defined to evaluate the effect of natural attenuation and enhanced remediation methods on the fate of BTEX. Two strategies were defined for cleaning up the site: (1) reduction of BTEX over the entire site down to the maximum concentration limit (MCL), and (2) remediation of the site to a level that reduces BTEX below MCLs only at the nearest discharge wells. The results show that under natural attenuation alone, the remediation time for benzene (time needed to decrease concentrations to a specified level) is more than 60 years, whereas that of TEX is longer, but only benzene will reach the receptors. LNAPL removal and enhanced bioremediation techniques could decrease this time to about 30 years for benzene. A cost-effective two-stage enhanced remediation operation should be applied. In the first stage, the entire dissolved BTEX plume should be treated, whereas in the second stage, after the remediation of benzene, the operation area should be limited to the remaining TEX plume areas. In the second strategy, air injection will be sufficient to prevent the BTEX plume from reaching the receptors. Addition of oxygen and hydrogen peroxide is likely too expensive.  相似文献   
62.
Numerous human genetic diseases are caused by mutations that give rise to aberrant alternative splicing. Recently, several of these debilitating disorders have been shown to be amenable for splice-correcting oligonucleotides (SCOs) that modify splicing patterns and restore the phenotype in experimental models. However, translational approaches are required to transform SCOs into usable drug products. In this study, we present a new cell-penetrating peptide, PepFect14 (PF14), which efficiently delivers SCOs to different cell models including HeLa pLuc705 and mdx mouse myotubes; a cell culture model of Duchenne's muscular dystrophy (DMD). Non-covalent PF14-SCO nanocomplexes induce splice-correction at rates higher than the commercially available lipid-based vector Lipofectamine 2000 (LF2000) and remain active in the presence of serum. Furthermore, we demonstrate the feasibility of incorporating this delivery system into solid formulations that could be suitable for several therapeutic applications. Solid dispersion technique is utilized and the formed solid formulations are as active as the freshly prepared nanocomplexes in solution even when stored at an elevated temperatures for several weeks. In contrast, LF2000 drastically loses activity after being subjected to same procedure. This shows that using PF14 is a very promising translational approach for the delivery of SCOs in different pharmaceutical forms.  相似文献   
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64.
This study investigated the developmental toxicity of carbendazim during the organogenesis period in mice. Mated CD-1 mice were administered carbendazim at dose levels 0, 150, 300, and 600 mg/kg/day by gavage. Body weights, weight gains, and feed consumption were significantly reduced in mice administered with 300 and 600 mg/kg/day. Carbendazim exposure increased maternal levels of cholesterol, triglyceride, glucose, protein, and creatinine; and reduced the levels of estradiol and progesterone in the 300- and 600-mg/kg/day groups. In addition, exposure to carbendazim significantly reduced the number of live fetuses and increased the number of dead and resorptions at the same dose levels. External, visceral, and skeleton malformations were observed in the 300- and 600-mg/kg/day. In conclusion, exposure of pregnant mice to carbendazim induced maternal and developmental toxicity at 300 and 600 mg/kg/day. 150 mg/kg/day carbendazim produced a very slight increase in postimplantation loss, which was within the range of historical controls, and no evidence of maternal toxicity.  相似文献   
65.
Several molecular aberrations have been implicated in the pathogenesis of pituitary tumors, but few have proven thus far to be of therapeutic value. Pituitary tumor-derived fibroblast growth factor receptor-4 (ptd-FGFR4) is an alternatively transcribed cytoplasmic isoform lacking most of the extracellular domain. This oncogene recapitulates the morphological features of human pituitary tumors in transgenic mice. To investigate the therapeutic potential of targeting ptd-FGFR4, we examined the impact of FGFR4 tyrosine kinase inhibition in xenografted mice. GH4 pituitary cells expressing ptd-FGFR4 develop into invasive tumors. Systemic treatment of mice bearing ptd-FGFR4 tumors with the FGFR-selective inhibitor PD173074 resulted in recovery of membranous N-cadherin staining and a significant reduction in tumor volume with less invasive growth behavior. Mutation of tyrosine Y754F in ptd-FGFR4 abrogated the effect of PD173074-mediated inhibition. The pivotal role of N-cadherin as a mediator of this pituitary cell growth was demonstrated by small interfering RNA mediated down-regulation, which promoted invasive growth in xenografted mice. To validate this model in primary human pituitary tumors, we examined the expression of ptd-FGFR4, N-cadherin, and clinical behavior. Loss of membranous N-cadherin correlated with cytoplasmic FGFR4 expression and with tumor invasiveness in surgically resected human pituitary tumors. Primary human pituitary tumor cells treated with PD173074 showed restoration of N-cadherin to the membrane with dephosphorylation of retinoblastoma protein. These data highlight the pathogenetic significance of N-cadherin misexpression and emphasize the importance of FGFR partnership in mediating its functions.  相似文献   
66.
A simple and green chemistry procedure for the synthesis of dihydropyrimidinones using heteropoly acid mediated cyclocondensation reaction is described. This method provides an efficient and much improved modification of the original Biginelli reaction reported in 1893, in terms of high yields, and short reaction times. It has the ability to allow a wide variety of substitutions in all three components.  相似文献   
67.
This study aimed to investigate the effects of aqueous cinnamon extract (ACE) on 7, 12-Dimethylbenz[a]anthracene (DMBA)-induced oral carcinogenesis in hamster cheek pouch (HCP) mucosa. Sixty male Syrian hamsters were randomly divided into six equal groups. The hamsters of groups I, II and III received no treatment, DMBA and ACE respectively, for 16 weeks. Groups IV and V were handled as group II and concomitantly treated with ACE for the same period and additionally group V received ACE for other 16 weeks after the stoppage of DMBA application. Group VI hamsters were handled as group III and additionally received DMBA for other 16 weeks after the stoppage of ACE supplementation. Hamsters of each group were euthanized according to the experimental schedule. The buccal pouches were and prepared for H&E stain, PAS reagent, CD3 and PDGF immunohistochemical reactivity. All groups showed dysplastic changes with varying degrees except groups I and III. Deep invasive carcinomas were recorded in 90% of the samples of group II, 60% of group IV, 50% of group V and 40% of group VI. From the previous results, it can be concluded that ACE has the potentiality preventing oral cancer initiation better than inhibiting oral cancer progression.  相似文献   
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69.
Basic fibroblast growth factor (bFGF; FGF-2) is one of 19 related members of a growth factor family with mitogenic and hormone-regulatory functions. In Xenopus laevis oocytes, a 1.5-kb FGF-2 antisense (GFG) RNA complementary to the third exon and 3'-untranslated region (UTR) of FGF-2 mRNA has been implicated in FGF-2 mRNA editing and stability. The human homolog has been cloned, and we localized this gene by yeast artificial chromosome (YAC), somatic cell, and radiation hybrid panels to the same chromosomal site as FGF-2 (chromosome 4, JO4513 adjacent to D4S430), confirming this as a human endogenous antisense gene. The full-length GFG antisense RNA encodes a 35-kDa protein, which is highly homologous with the MutT family of antimutator nucleosidetriphosphatases (NTPases). We show that human pituitary tumors express FGF-2 and its endogenous antisense partner GFG. While normal pituitary expresses GFG but not FGF-2, pituitary adenomas express FGF-2 and have reduced levels of GFG; aggressive and recurrent adenomas expressed more FGF than GFG mRNA. To examine the effects of this antisense gene in the pituitary, we transfected the pituitary-derived GH4 mammosomatotroph cell line with constructs encoding the full-length human GFG cDNA. Transiently and stably transfected cells expressed the 35-kDa GFG protein that was localized to the cytoplasm. These cells exhibited enhanced PRL expression as documented by transiently transfected PRL-luciferase reporter assay and by endogenous PRL protein. GFG expression in these cells did not alter endogenous FGF-2 expression but increased the proportion of the higher molecular mass 22-kDa form of GH. Moreover, GFG expression inhibited cell proliferation as shown by [(3)H]thymidine incorporation, proliferating cell nuclear antigen (PCNA) nuclear staining, and cell cycle analysis. We conclude that the GFG-encoded protein has divergent hormone-regulatory and antiproliferative actions in the pituitary that are independent of FGF-2 expression. GFG represents a novel mechanism involved in restraining pituitary tumor cell growth while promoting hormonal activity.  相似文献   
70.
Two chitinases, A and B, were purified from the culture supernatant of Streptomyces albovinaceus S-22 by ammonium sulphate fraction (80%) and Sephadex G-200 gel filtration. Both enzymes had molecular weights estimated to be 43 and 45kDa by SDS polyacrylamide gel electrophoresis. The enzymes were active at 40°C and pH 5.6 after 120min, and stable at temperatures below 40°C in the absence of chitin. The purified enzyme had potential for cell wall lysis of fungal pathogenesis tested.  相似文献   
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