Serial MR imaging of intracranial metastases after radiosurgery

Purpose: To evaluate the spatiotemporal evolution of radiosurgical induced changes both in metastases and in normal brain tissue adjacent to the lesions by serial magnetic resonance (MR) imaging. Methods and Materials: Thirty-five intracranial metastases of different primaries were treated in 25 patients by single high-dose radiosurgery. MR images acquired before radiosurgery were available in all patients. Sixty-three follow-up MR studies were performed in these patients including T₂- and contrast-enhanced T₁-weighted MR images. The average follow-up time was 9 ± 5 months (mean ± standard deviation [SD]). Based on contrast-enhanced T₁-weighted MR images, tumor response was radiologically classified in the following four groups: stable disease was assumed if the average tumor diameter after treatment did not show a tumor shrinkage of more than 50% and an increase of more than 25%, partial remission as a shrinkage of tumor size of more than 50%, a disappearance of contrast-enhancing tumor as a complete remission, and an increase of tumor diameter of more than 25% as tumor progress. Moreover, we analysed signal changes on T₂-weighted images in brain parenchyma adjacent to the enhancing metastases. Results: The overall mean survival time was 10.5 ± 7 months, with a 1-year actuarial survival rate of 40%. Stable disease, partial or complete remission of the metastatic tumor was observed in 22 patients (88%). Central or homogeneous loss of contrast enhancement appeared to be a good prognostic sign for stable disease or partial remission. This association was statistically significant (p < 0.05). Three patients (12%) suffered from tumor progression. In eight patients (32%) with stable disease or partial remission, signal changes on T₂-weighted images were observed in tissue adjacent to the contrast enhancing lesions. A progression of the high signal on T₂-weighted images was seen in seven of the eight patients between 3 and 6 months after therapy, followed by a signal regression 6–18 months after irradiation. Conclusion: MR imaging is a sensitive imaging tool to evaluate tumor response as well as the presence or absence of adjacent parenchymal changes following radiosurgery. Loss of homogeneous or central contrast enhancement on Gd-enhanced MR images appeared to be a good prognostic sign for tumor response. Tumor shrinkage seems not to be dependent on time. In addition, most cases of radiation induced changes in normal brain parenchyma observed on T₂-weighted images seem to be self limited.     

Image formation by dyeing of copolymers bearing photogenerated acid and base groups with dye bath containing acid and basic dyes

Copolymers bearing photoacid generating groups and/or photobase generating groups were dyed after UV irradiation with a dye bath containing both an acid dye and a basic dye. Acetophenone O‐acryloyloxime (AAPO) was used as a monomer bearing acyloxyimino (AOI) group that generates a primary amino group upon irradiation, which is followed by hydrolysis. Phenacylsulfonylstyrene (PSSt) and 1,2,3,4‐tetrahydronaphthylideneamino p‐styrenesulfonate (NISS) were chosen as monomers having β‐keto sulfone (β‐KS) and iminosulfonate (IS) groups, respectively, which yielded acid groups when irradiated. Copolymers of AAPO and methyl methacrylate (MMA) were dyed with only the acid dye, and those of PSSt or NISS were dyed with only the basic dye after irradiation. AAPO‐PSSt‐MMA films became dyeable with the acid dye when irradiated for a short time and with the basic dye with further irradiation. However, AAPO‐NISS‐MMA copolymers showed the reverse dyeing behavior. IR spectra revealed that AOI groups were photochemically decomposed prior to the β‐KS groups for AAPO‐PSSt‐MMA, and AOI and IS groups decomposed simultaneously for AAPO‐NISS‐MMA. These results suggested the possibility of adsorption of different ionic dyes on the films by a change of irradiation time; in fact, color patterns could be obtained in a single staining process using the dye bath. © 2000 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 38: 3043–3051, 2000     

Imaging with mass spectrometry: Which ionization technique is best?

The use of mass spectrometry (MS) to acquire molecular images of biological tissues and other substrates has developed into an indispensable analytical tool over the past 25 years. Imaging mass spectrometry technologies are widely used today to study the in situ spatial distributions for a variety of analytes. Early MS images were acquired using secondary ion mass spectrometry and matrix-assisted laser desorption/ionization. Researchers have also designed and developed other ionization techniques in recent years to probe surfaces and generate MS images, including desorption electrospray ionization (DESI), nanoDESI, laser ablation electrospray ionization, and infrared matrix-assisted laser desorption electrospray ionization. Investigators now have a plethora of ionization techniques to select from when performing imaging mass spectrometry experiments. This brief perspective will highlight the utility and relative figures of merit of these techniques within the context of their use in imaging mass spectrometry.     

Polarimetric-Spectral-Sensitive Compressed Ultrafast Photography Enables Real-Time Intensity Visualization of Time-Varying Polarized Ultrafast Laser Pulses

Ultrafast laser pulses with complex spatiotemporal and polarization couplings have shown great application prospects in coherent control, particle acceleration, molecular dynamics excitation, and chiral or anisotropic detection. It is very important to observe the polarization-coupled ultrafast laser pulses for characterizing the performance of laser source and understanding the laser-matter interaction, but there is currently no detection technique that can completely characterize them, including the spatio-, spectral-, and polarimetric-temporal information. In this work, a polarimetric-spectral-sensitive has been compressed ultrafast photography (PS-CUP) to realize the real-time intensity visualization of time-varying polarized (TP) ultrafast laser pulses. PS-CUP can not only distinguish the polarization state of a TP pulse, but also realize the spatio-, spectral- and polarimetric-temporal measurement. To demonstrate the ability of polarization resolving detection, PS-CUP is used to successfully distinguish between the sinistral and dextral TP pulses and measure the angle and degree of linear polarization of a dextral TP pulse, respectively, and the experimental results are highly consistent with theoretical simulations. Owing to the unprecedented multidimensional detection ability, PS-CUP is prospected to provide a powerful tool for the diagnosis of various complex ultrafast laser pulses and the detection of ultrafast chiral optics.     

Photogenerated base in polymer curing and imaging: Design of reactive styrenic copolymers susceptible to a base-catalyzed β-elimination

A novel family of functionalized styrenic copolymers that are susceptible to a base-catalyzed β-elimination reaction is reported. The reactive copolymers, poly-{(2-phenyl-2-cyanoethoxycarbonyloxystyrene)-co-(4-hydroxystyrene)}, are prepared by chemical modification of poly(4-hydroxystyrene) using 2-phenyl-2-cyanoethyl chloroformate. A photoresist material consisting of the copolymer and bis[[(2-nitrobenzyl)-oxy] carbonyl]-4,4′-trimethylenedipiperidine used as an amine photogenerator affords positive tone images by UV irradiation. The effect of copolymer structure and composition on imaging, thermal stability, and the ease of β-elimination reaction is discussed. © 1997 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 35 : 3543–3552 1997     

Development of a new software for the X-ray structural analysis of polymer crystals by utilizing the X-ray imaging plate system

A software and some useful tools have been developed for identifying individual x-ray reflectional peaks recorded with an x-ray imaging plate system. These techniques were applied to analyze the crystal structure of uniaxially oriented polymer samples. Characteristic features of the present method may be summarized as follows. (1) The indexing of the observed reflections and the determination of the unit cell parameters can be made easily on the display of the computer. (2) The integrated intensity of the individual component of the overlapped reflections can be evaluated quantitatively through the curve separation technique. The R_merge's for the equivalent reflections were 5–6%, indicating the exact evaluation of the integrated intensities. (3) The thus obtained reflectional data were successfully utilized for the extraction of the initial structural models by the direct method. The actual applications have been made for orthorhombic polyethylene, trigonal polyoxymethylene, and isotactic polybutene-1, giving the refined crystal structures including even the positions of hydrogen atoms in some cases. The reliability factors were 12, 5, and 15%, respectively, for these three polymer cyrstals. © 1997 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 35: 1677–1700, 1997     

透明质酸纳米材料在荧光/光声成像和光疗中的应用

荧光/光声成像和光疗技术的生物医学应用引起了人们越来越多的关注, 然而很多荧光/光声造影剂存在生物相容性较差, 缺乏肿瘤靶向性, 信噪比较低, 功能单一等共性问题, 严重限制其诊疗应用. 透明质酸具有优异的生物相容性和主动肿瘤靶向性, 可被透明质酸酶降解, 并且易于化学修饰和实现多种超分子弱相互作用力协同工作. 因此, 人们将透明质酸与荧光/光声造影剂结合制备纳米材料, 使其在细胞乃至活体的标记性能和治疗效果获得了很大的改善. 本文综述了将两类物质结合制备纳米材料的方法, 着重阐述了纳米材料的结构与性能关系, 为其未来设计和开发提供了指导, 最后对存在的主要问题以及未来的重要研究方向进行了分析和展望.     

Studying anomalous diffusion in a liquid crystal/ polymer system using fast FTIR imaging

The diffusion of liquid crystal 4‐n‐pentyl‐4′‐cyanobiphenyl (5CB) into a poly(butyl methacrylate) (PBMA) matrix has been studied using fast FTIR imaging. The concentration profiles were obtained as a function of time at several temperatures above and below the nematic to isotropic transition temperature (T_NI) of 5CB and the T_g of PBMA. The time‐dependent progression of the diffusion front position, when fitted to a power law model, exhibited exponential values between 0.40 and 0.52. This, along with the observed progression of a sharp 5CB‐diffusion front into the PBMA matrix, indicates the presence of an anomalous diffusion process. It was shown that fast FTIR was able to correctly identify the diffusion process as anomalous, whereas a simple mass uptake analysis would have led to the conclusion that the process proceeded according to Fick's second law. © 1999 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 37: 2261–2268, 1999     

多光谱法结合分子对接研究柠檬黄与牛血清白蛋白的相互作用

采用荧光光谱法、同步荧光光谱法、三维荧光光谱法、紫外光谱法以及分子对接法研究了柠檬黄与牛血清白蛋白(BSA)的相互作用.柠檬黄与BSA相互作用的荧光光谱分析表明柠檬黄能有效猝灭BSA的内源荧光,根据Stern-Volmer方程计算得到柠檬黄对BSA的荧光猝灭常数KSV随着温度的升高而逐渐降低,表明柠檬黄对BSA的荧光猝...     

Organic Nanoplatforms for Iodinated Contrast Media in CT Imaging

X-ray computed tomography (CT) imaging can produce three-dimensional and high-resolution anatomical images without invasion, which is extremely useful for disease diagnosis in the clinic. However, its applications are still severely limited by the intrinsic drawbacks of contrast media (mainly iodinated water-soluble molecules), such as rapid clearance, serious toxicity, inefficient targetability and poor sensitivity. Due to their high biocompatibility, flexibility in preparation and modification and simplicity for drug loading, organic nanoparticles (NPs), including liposomes, nanoemulsions, micelles, polymersomes, dendrimers, polymer conjugates and polymeric particles, have demonstrated tremendous potential for use in the efficient delivery of iodinated contrast media (ICMs). Herein, we comprehensively summarized the strategies and applications of organic NPs, especially polymer-based NPs, for the delivery of ICMs in CT imaging. We mainly focused on the use of polymeric nanoplatforms to prolong circulation time, reduce toxicity and enhance the targetability of ICMs. The emergence of some new technologies, such as theragnostic NPs and multimodal imaging and their clinical translations, are also discussed.