988 resultados para Land Administration Domain Model
Resumo:
Objective: The management of sarcoma metastasis by systemic chemotherapy is often unsatisfactory. This has paradoxally been attributed to the leakiness of tumor neovessels which induce high intratumor interstitial fluid pressure (IFP) and limit convection forces that are important for drug distribution. In a rodent model, we have recently shown that photodynamic (PDT) pre treatment of lung metastasis could enhance their uptake of chemotherapy. We hypothesized that PDT transiently decreases tumor IFP which enhances convection and promotes drug distribution.Methods: Sarcoma tumors were generated sub-pleurally in the lungs of 12 rats. Animals were randomized at 10 days into i. no pre-treatment (control) and ii. low dose PDT pre-treatment (0・0625 mg/kg Visudyne, 10J/cm2 and 35 mW/cm2) followed by intravenous Liposomal doxorubicin (LiporubicinTM) administration. Using the wick-in-needle technique, we determined tumor and normal tissue IFP before, during and after PDT. In parallel, the uptake of LiporubicinTM was determined by high performance liquid chromatography in tumor and lung tissues.Results: Tumor IFP was significantly higher than normal tissue IFP in all animals. PDT pre-treatment did not affect normal tissue IFP but caused a significant decrease in tumor IFP (mean decrease by 2+/− 1mmHg) which lasted an average of 30 minutes before reaching baseline values. Tumor but not normal lung tissue LiporubicinTM uptake was significantly increased by 67% with PDT pre-treatment when liporubicin was allowed to circulate for one hour.Conclusion: Photodynamic therapy pre-treatment enhances LiporubicinTM uptake in sarcoma lung metastasis by transiently decreasing tumor IFP. These PDT conditions seem to specifically modulate tumor neovessels but not normal lung vessels.
Resumo:
Background and objectives: Interleukin-18 (IL-18) is a pleiotropic cytokine involved in rheumatoid arthritis (RA) pathogenesis. This studywas carried out to evaluate the efficicacy of interleukin-18 binding protein (IL-18BP) gene therapy in the rat adjuvant-induced arthritis (AIA) model and to decipher the mechanisms by which IL-18BP delivery lessens bone destruction. Materials and methods: Arthritis was induced in female Lewis rat by Mycobacterium butyricum and the mRNA expression of IL-18 and IL-18BP was determined in the joints. In a preventative study, rats were divided into an adenovirus producing IL-18BP-Fc (AdmIL-18BP-Fc) group (n=8) and an adenovirus producing green fluorescent protein (AdGFP) group (n=7). On day 8 after AIA induction, adenoviruses were injected. Clinical parameters were assessed. At day 18, during maximal arthritis, the rats were euthanized, ankles were collected, and X-rays were performed. mRNA and protein were extracted from joints for analyses by qRT-PCR, multiplex, Western blot, and zymography. Results: We observed a decrease in the [IL-18BP/IL-18] ratio from day 7 to day 45. Administration of AdmIL-18BPd-Fc decreased clinical parameters and prevented bone and joint destruction compared to AdGFP administration. IL-18BP delivery reduced the metalloproteinase 9 (MMP-9) levels by 33% (at protein level (Fig. 1B) and functional level (Fig. 1C) and the tartrate-resistant acid phosphatase (TRAP) level by 44% (Fig. 1D) in the joint homogenates from AdmIL-18BPd-Fc compared to AdGFP treated rats.However, no variationwas observed forMMP-2 at the protein level (Fig.1A) and functional level (Fig. 1C). Conclusions: In rat AIA, a decrease in the [IL-18BP/ IL-18] ratio was observed. IL-18BP delivery prevented joint and bone destruction by downregulating MMP-9 and TRAP, suggesting a potential benefit of a similar therapy in RA.
Resumo:
In the presence of 2-hydroxybiphenyl, the enhancer binding protein, HbpR, activates the sigma54-dependent P(hbpC) promoter and controls the initial steps of 2-hydroxybiphenyl degradation in Pseudomonas azelaica. In the activation process, an oligomeric HbpR complex of unknown subunit composition binds to an operator region containing two imperfect palindromic sequences. Here, the HbpR-DNA binding interactions were investigated by site-directed mutagenesis of the operator region and by DNA-binding assays using purified HbpR. Mutations that disrupted the twofold symmetry in the palindromes did not affect the binding affinity of HbpR, but various mutations along a 60 bp region, and also outside the direct palindromic sequences, decreased the binding affinity. Footprints of HbpR on mutant operator fragments showed that a partial loss of binding contacts occurs, suggesting that the binding of one HbpR 'protomer' in the oligomeric complex is impaired whilst leaving the other contacts intact. An HbpR variant, devoid of its N-terminal sensing A-domain, was unable to activate transcription from the hbpC promoter while maintaining protection of the operator DNA in footprints. Wild-type HbpR was unable to activate transcription from the hbpC promoter when delta A-HbpR was expressed in the same cell, suggesting the formation of (repressing) hetero-oligomers. This model implies that HbpR can self-associate on its operator DNA without effector recognition or ATP binding. Furthermore, our findings suggest that the N-terminal sensing domain of HbpR is needed to activate the central ATPase domain rather than to repress a constitutively active C domain, as is the case for the related regulatory protein XylR.
Resumo:
[Acte royal]
Resumo:
[Acte royal]
Resumo:
Over the past two decades, soil ecotoxicologists have made strides in utilizing the basic concepts and advancements in soil zoology and ecology. They have applied the existing tools, and developed new ones to investigate how chemical contamination can affect soil ecosystems, including the degradation or destruction of soil quality and habitats or the diminishment of belowground biodiversity. Soil ecotoxicologists are applying a suite of standard protocols, originally developed as laboratory tests with single chemicals (e.g., pesticides), and further enhancing both the approaches and protocols for the assessment of contaminated lands. However, ecological relevance of some approaches remains unresolved. The authors discuss the main challenges for a coherent ecotoxicological assessment of soil ecosystems amid contaminated lands, and provide recommendations on how to integrate the effects of physical and chemical soil properties, the variations in the diversity of soil invertebrates, and the interactions among organisms of various trophic levels. The review examines new international approaches and test methods using examples from three continents (in particular research conducted in Brazil), and provides recommendations for improving ecological relevance of ecotoxicological investigations of contaminated lands.