V5
李旭
李旭 化学
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北京 东城区 积分
2186
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6
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65
化学

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V5 李旭 声望 75 化学 5天前 上传
USP22 is a positive regulator of NFATc2 on promoting IL2 expression
Abstract Nuclear factor of activated T cells (NFAT) is an important regulator of T cell activation. However, the molecular mechanism whereby NFATc2 regulates IL2 transcription is not fully understood. In this study, we showed that ubiquitin-specific protease 22 (USP22), known as a cancer stem cell marker, specifically interacted with and deubiquitinated NFATc2. USP22 stabilized NFATc2 protein levels, which required its deubiquitinase activity. Consistent with these observations, depletion of USP22 in T cells reduced the expression of IL2, which is a cytokine that signifies T effector cell activation. Our findings thus unveil a previously uncharacterized positive regulator of NFATc2, suggesting that targeting the deubiquitinase activity of USP22 could have therapeutic benefit to control IL2 expression and T cell function.
V5 李旭 声望 75 化学 2周前 上传
Image-guided tumour biopsies in a prospective molecular triage study (MOSCATO-01): What are the real risks?
Abstract Purpose To evaluate efficacy, complications and preprocedural risk factors for percutaneous image-guided core needle biopsy of malignant tumours for genomic tumour analysis. Materials and methods Procedural data for core biopsies performed at a single centre for the MOSCATO-01 clinical trial were prospectively recorded between December 2011 and March 2016. Data assessed included patient demographics, tumour characteristics, procedural outcomes and complications. Results A total of 877 biopsies were performed under computed tomography (38.4%) or ultrasound guidance (61.6%) for tumours in the liver (n = 363), lungs (n = 229), lymph nodes (n = 138), bones (n = 15) and other miscellaneous sites (n = 124). Each biopsy harvested a mean 4.4 samples [1–15], with adequate tumour yield for genomic analysis in 95.3% of cases. Procedural complications occurred in 89 cases (10.1%), with minor grade I complications in 59 (66.3%); grade II in 16 (18%) and grade III in 14 (15.7%). No grade IV complications and no procedure-related death occurred. The most common complications were pneumothorax (51/89, 57.3%), haemorrhage (24/89, 27%) and pain (8/89, 8.9%). Predictive factors for complications by univariate analysis included biopsied organ (lung vs other), sample number, prone position, lesion size, lesion depth and biopsy approach. By multivariate analysis, only pulmonary biopsy was a significant risk factor (odds ratio = 27.23 [4.93–242.76], p < 0.01). Conclusion Percutaneous image-guided core needle biopsy in cancer patients provides an effective method to obtain molecular screening samples, with an overall low complication rate. Lung mass biopsies present a higher risk of complication, although complications are manageable by minimally invasive techniques without prolonged sequelae.
V5 李旭 声望 75 化学 2周前 上传
The first clinical implementation of a real-time six degree of freedom target tracking system during radiation therapy based on Kilovoltage Intrafraction Monitoring (KIM)
Abstract Purpose We present the first clinical implementation of a real-time six-degree of freedom (6DoF) Kilovoltage Intrafraction Monitoring (KIM) system which tracks the cancer target translational and rotational motions during treatment. The method was applied to measure and correct for target motion during stereotactic body radiotherapy (SBRT) for prostate cancer. Methods Patient: A patient with prostate adenocarcinoma undergoing SBRT with 36.25 Gy, delivered in 5 fractions was enrolled in the study. 6DoF KIM technology: 2D positions of three implanted gold markers in each of the kV images (125 kV, 10 mA at 11 Hz) were acquired continuously during treatment. The 2D → 3D target position estimation was based on a probability distribution function. The 3D → 6DoF target rotation was calculated using an iterative closest point algorithm. The accuracy and precision of the KIM method was measured by comparing the real-time results with kV-MV triangulation. Results Of the five treatment fractions, KIM was utilised successfully in four fractions. The intrafraction prostate motion resulted in three couch shifts in two fractions when the prostate motion exceeded the pre-set action threshold of 2 mm for more than 5 s. KIM translational accuracy and precision were 0.3 ± 0.6 mm, −0.2 ± 0.3 mm and 0.2 ± 0.7 mm in the Left-Right (LR), Superior-Inferior (SI) and Anterior-Posterior (AP) directions, respectively. The KIM rotational accuracy and precision were 0.8° ± 2.0°, −0.5° ± 3.3° and 0.3° ± 1.6° in the roll, pitch and yaw directions, respectively. Conclusion This treatment represents, to the best of our knowledge, the first time a cancer patient’s tumour position and rotation have been monitored in real-time during treatment. The 6 DoF KIM system has sub-millimetre accuracy and precision in all three translational axes, and less than 1° accuracy and 4° precision in all three rotational axes.
V5 李旭 声望 75 化学 3周前 上传
Functional lung imaging in radiation therapy for lung cancer: A systematic review and meta-analysis
Abstract Rationale Advanced imaging techniques allow functional information to be derived and integrated into treatment planning. Methods A systematic review was conducted with the primary objective to evaluate the ability of functional lung imaging to predict risk of radiation pneumonitis. Secondary objectives were to evaluate dose–response relationships on post treatment functional imaging and assess the utility in including functional lung information into treatment planning. A structured search for publications was performed following PRISMA guidelines and registered on PROSPERO. Results 814 articles were screened against review criteria and 114 publications met criteria. Methods of identifying functional lung included using CT, MRI, SPECT and PET to image ventilation or perfusion. Six studies compared differences between functional and anatomical lung imaging at predicting radiation pneumonitis. These found higher predictive values using functional lung imaging. Twenty-one studies identified a dose–response relationship on post-treatment functional lung imaging. Nineteen planning studies demonstrated the ability of functional lung optimised planning techniques to spare regions of functional lung. Meta-analysis of these studies found that mean (95% CI) functional volume receiving 20 Gy was reduced by 4.2% [95% CI: 2.3: 6.0] and mean lung dose by 2.2 Gy [95% CI: 1.2: 3.3] when plans were optimised to spare functional lung. There was significant variation between publications in the definition of functional lung. Conclusion Functional lung imaging may have potential utility in radiation therapy planning and delivery, although significant heterogeneity was identified in approaches and reporting. Recommendations have been made based on the available evidence for future functional lung trials.
V5 李旭 声望 75 化学 1个月前 上传
GsMTx4: Mechanism of Inhibiting Mechanosensitive Ion Channels
Abstract GsMTx4 is a spider venom peptide that inhibits cationic mechanosensitive channels (MSCs). It has six lysine residues that have been proposed to affect membrane binding. We synthesized six analogs with single lysine-to-glutamate substitutions and tested them against Piezo1 channels in outside-out patches and independently measured lipid binding. Four analogs had ∼20% lower efficacy than the wild-type (WT) peptide. The equilibrium constants calculated from the rates of inhibition and washout did not correlate with the changes in inhibition. The lipid association strength of the WT GsMTx4 and the analogs was determined by tryptophan autofluorescence quenching and isothermal calorimetry with membrane vesicles and showed no significant differences in binding energy. Tryptophan fluorescence-quenching assays showed that both WT and analog peptides bound superficially near the lipid-water interface, although analogs penetrated deeper. Peptide-lipid association, as a function of lipid surface pressure, was investigated in Langmuir monolayers. The peptides occupied a large fraction of the expanded monolayer area, but that fraction was reduced by peptide expulsion as the pressure approached the monolayer-bilayer equivalence pressure. Analogs with compromised efficacy had pressure-area isotherms with steeper slopes in this region, suggesting tighter peptide association. The pressure-dependent redistribution of peptide between “deep” and “shallow” binding modes was supported by molecular dynamics (MD) simulations of the peptide-monolayer system under different area constraints. These data suggest a model placing GsMTx4 at the membrane surface, where it is stabilized by the lysines, and occupying a small fraction of the surface area in unstressed membranes. When applied tension reduces lateral pressure in the lipids, the peptides penetrate deeper acting as “area reservoirs” leading to partial relaxation of the outer monolayer, thereby reducing the effective magnitude of stimulus acting on the MSC gate.

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