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Xiaoyuan Chen

Bio: Xiaoyuan Chen is an academic researcher from National University of Singapore. The author has contributed to research in topics: Physics & Photothermal therapy. The author has an hindex of 149, co-authored 994 publications receiving 89870 citations. Previous affiliations of Xiaoyuan Chen include Brown University & University of Southern California.


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TL;DR: Wang et al. as discussed by the authors developed a new ER-specific radioiodine-labeled estrogen derivative (131I]IPBA-EE), which was modified with an albumin-specific ligand 4-(p-iodophenyl) butyric acid (IPBA) to improve the metabolic stability and enhance the ER-targeting ability.
Abstract: Overexpression of estrogen receptors (ERs) is one of the important characteristics of most breast cancers. We aim to develop a new type of ER-specific radioiodine-labeled estrogen derivative ([131I]IPBA-EE), which was modified with an albumin-specific ligand 4-(p-iodophenyl) butyric acid (IPBA) to improve the metabolic stability and enhance the ER-targeting ability of estrogen. [131I]IPBA-EE can effectively bind to albumin in vitro, and its dissociation constant (Kd = 0.31 μM) is similar to IPBA (Kd = 0.30 μM). The uptake of [131I]IPBA-EE in ER-positive MCF-7 cells (41.81 ± 3.41%) was significantly higher than that in ER-negative MDA-MB-231 cells (8.78 ± 2.37%, ***P < 0.0005) and could be significantly blocked (3.92 ± 0.35%, ***P < 0.0005). The uptakes of [131I]IPBA-EE in rat uterus and ovaries were 5.66 ± 0.34% ID/g and 5.71 ± 2.77% ID/g, respectively, at 1 h p.i., and these uptakes could be blocked by estradiol (uterus: 2.81 ± 0.41% ID/g, *P < 0.05; ovarian: 3.02 ± 0.08% ID/g, *P < 0.05). SPECT/CT imaging showed that ER-positive MCF-7 tumor uptake of [131I]IPBA-EE reached to 6.07 ± 0.20% ID/g at 7 h p.i., which was significantly higher than that of ER-negative MDA-MB-231 tumor (0.87 ± 0.08% ID/g, **P < 0.005) and could be blocked obviously with fulvestrant (1.65 ± 1.56% ID/g, *P < 0.05). In conclusion, a novel radioiodinated estradiol derivative, [131I]IPBA-EE with albumin-binding property and good metabolic stability, was developed to image the ER in breast cancer. This promising ER-targeted probe has the potential to warrant further preclinical investigations.

3 citations

Journal ArticleDOI
TL;DR: The combined probe strategy developed in this study can dramatically reduce the renal accumulation of a peptide radioligand without affecting the tumor uptake, which shows great potential in peptide-based radiotheranostics.
Abstract: High and sustained renal radioactivity accumulation is a major challenge in peptide-based radionuclide imaging and therapy. However, neutral endopeptidase (NEP)-based enzymatic hydrolysis to release and excrete the radioactive fragments has been proven to be an effective and promising way to reduce renal accumulation. Despite the improvement, the effect is still far from being satisfactory. To further reduce kidney uptake, we studied the relationship between the enzymatic reaction rate and the substrate concentration and came up with a combined probe strategy. Model compounds Boc-MVK-Dde and Boc-MFK-Dde were used for an in vitro enzymatic digestion study. NOTA-Exendin 4 and NOTA-MVK-Exendin 4 were labeled with 64Cu for in vivo dose-dependent micro-positron emission tomography (PET) studies. Groups 1 and 2 were injected with 0.2 and 0.8 nmol of 64Cu-NOTA-Exendin 4, respectively. Groups 3-6 were injected with 0.2, 0.8, 1.0, and 1.4 nmol of 64Cu-NOTA-MVK-Exendin 4, respectively. Groups 7 and 8 were co-injected with 0.2 nmol of 64Cu-NOTA-MVK-Exendin 4 and NOTA-MVK-PEG5K (1.3 and 2.6 nmol). The radioactivity uptakes were determined and compared within and among the groups. The in vitro cleavage study for both Boc-MVK-Dde and Boc-MFK-Dde indicated that within a certain concentration range, the enzyme digestion rate increased with increasing substrate concentration. The microPET images showed that the renal clearance could be accelerated significantly by increasing the injection dose of 64Cu-NOTA-MVK-Exendin 4, with the kidney uptakes being 60.98, 43.01, and 16.10 % ID/g at 1 h for groups 3, 4 and 5, respectively. Unfortunately, the tumor uptakes were also significantly inhibited as the injected dose of the tracer increased. However, with the co-injection of NOTA-MVK-PEG5K, the renal accumulation was significantly decreased without hampering the tumor uptake. As a result, the tumor-to-kidney ratios were significantly improved, which were 1.93, 3.47, 1.74, and 3.38 times that of group 3 at 1, 4, 24, and 48 h, respectively. The enzymatic reaction rate of NEP is dependent on the concentration of the substrates both in vitro and in vivo. The combined probe strategy developed in this study can dramatically reduce the renal accumulation of a peptide radioligand without affecting the tumor uptake, which shows great potential in peptide-based radiotheranostics.

3 citations

Journal Article
TL;DR: In this article, a boron-derived leucine derivative was synthesized to mimic Leu, of which the transportation depends on L-type amino acid transporter (LAT), and the 18F-19F isotope exchange reaction was conducted for radiolabeling and quality control was performed by both HPLC and radioTLC.
Abstract: 1061 Objectives Non-invasively differentiating tumor from inflammation is a long-standing challenge for cancer diagnosis. In clinics, a biopsy or surgery is often required to justify the malignancy of certain types of cancer. Previously, positron emission tomography (PET) with 18F-FDG is the standard non-invasive technique for cancer imaging. However, FDG highlights any tissue with high energy consumption and is not tumor-specific. In addition to accumulating in fast growing tumors, FDG accumulation may be observed in a variety of healthy tissues and ones affected by various non-neoplastic pathologic conditions, such as acute and chronic inflammations and infections. Herein we report a 18F-labeled boron-derived leucine derivative (B-Leu) to distinguish cancer from inflammation in living systems. Methods A boron-derived leucine derivative was synthesized to mimic Leu, of which the transportation depends on L-type amino acid transporter (LAT). 18F-19F isotope exchange reaction was conducted for radiolabeling and quality control was performed by both HPLC and radioTLC. The metabolic stability of 18F-B-Leu was assessed both in vitro and in vivo. PET imaging and bio-distribution studies were performed in mice bearing UM22B xenografts on the right shoulder and inflammation in the left hind limb (Inflammation was introduced by intramuscular injection of turpentine 72 h prior to PET scan). Results The intracellular uptake of B-Leu was highly selective and competed effectively with natural Leu. The cellular uptake of B-Leu increased when incubated with the transfected cells express higher level of LAT-1, and a nearly linear relationship was found between the cellular uptake of Leu and the LAT-1 expression. Remarkably, 18F-B-Leu is highly metabolically stable, which is a unique advantage because metabolism of imaging probe often results in low tumor-specificity with high background uptake. As expected, 18F-B-Leu showed high accumulation in UM22B tumor (12.5 ± 3.1 %ID/g) and low uptake in the rest of the body (liver, 2.23 ± 0.46 %ID/g; muscle, 2.01 ± 0.53 %ID/g; and blood, 1.49 ± 0.82%ID/g). The tracer had predominant renal clearance but with low kidney retention. In addition, representative PET images demonstrated that 18F-B-Leu does not accumulate, but 18F-FDG does accumulate, in the inflammation region. Conclusions A boron-derived Leu derivative was developed and evaluated for targeting LAT-1 expression with PET. Administration of 18F-B-Leu allowed for clear visualization of tumor xenografts in mice, with almost negligible uptake in the inflammatory foci, suggesting a unique advantage over 18F-FDG, which is currently the gold standard PET tracer for clinical diagnosis. Figure: Compared with 11C-Leu and 18F-FDG, 18F-B-Leu showed specific accumulation in the tumor, and notably lower uptake in other major organs and inflammatory lesion.(A), (B) and (C) Whole-body maximum intensity projection PET images of a UM22B bearing mouse showing the uptake of 11C-Leu (A), 18F-B-Leu (B) and 18F-FDG (C). Tumor (t), bladder (b) and inflammation (i) were indicated by white arrows.

3 citations

Journal ArticleDOI
TL;DR: The first measurement of the relative phase for a ψ(3686) decay into a pair of Ξ−Ξ¯+ hyperons was reported in this article , with a significance of 7.3σ.
Abstract: Using a sample of (448.1±2.9)×106 ψ(3686) decays collected with the BESIII detector at BEPCII, we report an observation of Ξ− transverse polarization with a significance of 7.3σ in the decay ψ(3686)→Ξ−Ξ¯+ (Ξ−→Λπ−, Ξ¯+→Λ¯π+, Λ→pπ−, Λ¯→p¯π+). The relative phase of the electric and magnetic form factors is determined to be ΔΦ=(0.667±0.111±0.058) rad. This is the first measurement of the relative phase for a ψ(3686) decay into a pair of Ξ−Ξ¯+ hyperons. The Ξ− decay parameters (αΞ−, ϕΞ−) and their conjugates (αΞ¯+, ϕΞ¯+), the angular-distribution parameter αψ, and the strong-phase difference δp−δs for Λπ− scattering are measured to be consistent with previous BESIII results.Received 23 June 2022Accepted 25 October 2022DOI:https://doi.org/10.1103/PhysRevD.106.L091101Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article’s title, journal citation, and DOI. Funded by SCOAP3.Published by the American Physical SocietyPhysics Subject Headings (PhySH)Research AreasSpin polarizationStrong interactionPropertiesCP symmetryParticles & Fields

3 citations

Journal ArticleDOI
TL;DR: Molecular imaging has shown great potential in early detection of diseases, stratifying patients into potential responders and non responders to a given treatment, designing personalized treatment, monitoring treatment efficacy, drug discovery, and development, as well as better understanding of biology and pathophysiology.
Abstract: Molecular imaging (Weissleder et al. 2010), an emerging research field, with an emphasis on visualization and quantification of biological processes at the molecular and cellular levels, has shown great potential in early detection of diseases, stratifying patients into potential responders and non responders to a given treatment, designing personalized treatment, monitoring treatment efficacy, drug discovery, and development, as well as better understanding of biology and pathophysiology.

3 citations


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TL;DR: There is, I think, something ethereal about i —the square root of minus one, which seems an odd beast at that time—an intruder hovering on the edge of reality.
Abstract: There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality. Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

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Journal ArticleDOI
TL;DR: The interest in nanoscale materials stems from the fact that new properties are acquired at this length scale and, equally important, that these properties are equally important.
Abstract: The interest in nanoscale materials stems from the fact that new properties are acquired at this length scale and, equally important, that these properties * To whom correspondence should be addressed. Phone, 404-8940292; fax, 404-894-0294; e-mail, mostafa.el-sayed@ chemistry.gatech.edu. † Case Western Reserve UniversitysMillis 2258. ‡ Phone, 216-368-5918; fax, 216-368-3006; e-mail, burda@case.edu. § Georgia Institute of Technology. 1025 Chem. Rev. 2005, 105, 1025−1102

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