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Wenhui Ma, Fanfan Fu, Jingyi Zhu, Rui Huang, Yizhou Zhu, Zhenwei Liu, Jing Wang, Peter S Conti, Xiangyang Shi, Kai Chen
We report the use of multifunctional folic acid (FA)-modified dendrimers as a platform to radiolabel with 64Cu for PET imaging of folate receptor (FR)-expressing tumors. In this study, amine-terminated generation 5 (G5) poly(amidoamine) dendrimers were sequentially modified with fluorescein isothiocyanate (FI), FA, and 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid (DOTA), followed by acetylation of the remaining dendrimer terminal amines. The as-formed multifunctional DOTA-FA-FI-G5·NHAc dendrimers were then radiolabeled with 64Cu via the DOTA chelation...
March 16, 2018: Nanoscale
Fanxing Zeng, Jonathon A Nye, Ronald J Voll, Leonard Howell, Mark M Goodman
Nine pyridyloxypyridyl indole carboxamides were synthesized and displayed high affinities for 5-HT2C receptors and high selectivity over 5-HT2A and 5-HT2B . Among them, 6-methyl- N -[6-[(2-methyl-3-pyridinyl)oxy]-3-pyridinyl]1 H -indole-3-carboxamide ( 8 ) exhibits the highest 5-HT2C binding affinity ( K i = 1.3 nM) and high selectivity over 5-HT2A (∼1000 times) and 5-HT2B (∼140 times). [11 C] 8 was synthesized by palladium-catalyzed coupling reaction between pinacolboranate 16 and [11 C]CH3 I with an average radiochemical yield of 27 ± 4% ( n = 8, decay-corrected from end of [11 C]CH3 I synthesis)...
March 8, 2018: ACS Medicinal Chemistry Letters
Zhengyuan Zhou, Satish K Chitneni, Nick Devoogdt, Michael R Zalutsky, Ganesan Vaidyanathan
In a previous study, we evaluated a HER2-specific single domain antibody fragment (sdAb) 2Rs15d labeled with18 F via conjugation of a residualizing prosthetic agent that was synthesized by copper-catalyzed azide-alkyne cycloaddition (CuAAC). In order to potentially increase overall efficiency and decrease the time required for labeling, we now investigate the use of a strain-promoted azide-alkyne cycloaddition (SPAAC) between the 2Rs15d sdAb, which had been pre-derivatized with an azide-containing residualizing moiety, and an18 F-labeled aza-dibenzocyclooctyne derivative...
March 10, 2018: Bioorganic & Medicinal Chemistry
Zhihao Zha, Karl Ploessl, Brian P Lieberman, Limin Wang, Hank F Kung
INTRODUCTION: Glutamine is an essential source of energy, metabolic substrates, and building block for supporting tumor proliferation. Previously, [18 F](2S,4R)4-fluoroglutamine (4F-Gln) was reported as a glutamine-related metabolic imaging agent. To improve the in vivo kinetics of this radiotracer, two new dipeptides, [18 F]Gly-(2S,4R)4-fluoroglutamine (Gly-4F-Gln) and [18 F]Ala-(2S,4R)4-fluoroglutamine (Ala-4F-Gln) were investigated. METHODS: Radiolabeling was performed via 2-steps18 F-fluorination...
February 13, 2018: Nuclear Medicine and Biology
Mehran Makvandi, Austin Pantel, Lauren Schwartz, Erin Schubert, Kuiying Xu, Chia-Ju Hsieh, Catherine Hou, Hyoung Kim, Chi-Chang Weng, Harrison Winters, Robert Doot, Michael D Farwell, Daniel A Pryma, Roger A Greenberg, David A Mankoff, Fiona Simpkins, Robert H Mach, Lilie L Lin
BACKGROUND: Poly(ADP-ribose) polymerase (PARP) inhibitors are effective in a broad population of ovarian cancer patients, however resistance caused by low enzyme expression of the drug target, poly(ADP-ribose) polymerase 1 (PARP-1), remains to be clinically evaluated in this context. We hypothesize that PARP-1 expression is variable in ovarian cancer and can be quantified in primary and metastatic disease using a novel positron emitting tomography (PET) imaging agent. METHODS: We used a translational approach to describe the significance of PET imaging of PARP-1 in ovarian cancer...
March 6, 2018: Journal of Clinical Investigation
Shuai Liu, Bingxin Gu, Jianping Zhang, Yongping Zhang, Xiaoping Xu, Huiyu Yuan, Yingjian Zhang, Zhongyi Yang
OBJECTIVE: Our study aimed to investigate the feasibility of PET/CT for monitoring the influence of fulvestrant on sensitizing docetaxel by downregulating ERα in ERα+ breast cancer. METHODS: Docetaxel-insensitive ERα+ breast cancer cells (DIS-ZR751) were established, identified and cultured. ERα expression, toxicity and viability of DIS-ZR751 were analyzed before and after treatment in vitro. DIS-ZR751-bearing nude mice were randomly divided into four groups according to different treatments: blank (DIS-ZR751), docetaxel (DIS-ZR751+DOC), fulvestrant (DIS-ZR751+FUL), and combination treatment (DIS-ZR751+DOC+FUL)...
February 24, 2018: Annals of Nuclear Medicine
Duo Xu, Rongqiang Zhuang, Linyi You, Zhide Guo, Xiangyu Wang, Chenyu Peng, Deliang Zhang, Pu Zhang, Hua Wu, Weimin Pan, Xianzhong Zhang
INTRODUCTION: A novel radiotracer 1‑(2‑(2‑(2‑[18 F]fluoroethoxy)ethoxy)ethyl)‑1H‑1,2,3‑triazole‑estradiol ([18 F]FETE) was successfully synthesized, characterized and evaluated in mice for estrogen receptor (ER)-positive breast cancer targeting with positron emission tomography (PET) imaging. METHODS: The tosylate precursor 3 was radiolabeled with18 F and then reacted with 17α‑ethinyl‑estradiol to produce the final [18 F]FETE. The physicochemical properties of [18 F]FETE were tested in vitro, including determination of the octanol/water partition coefficient, stability and cellular uptake in MCF-7 (ER-positive) and MDA-MB-231 (ER-negative) cells...
February 2, 2018: Nuclear Medicine and Biology
Zhihao Zha, Karl Ploessl, Seok Rye Choi, Zehui Wu, Lin Zhu, Hank F Kung
INTRODUCTION: Prostate specific membrane antigen (PSMA) is a well-established target for diagnostic and therapeutic applications for prostate cancer. It is know that [68 Ga]PSMA 11 ([68 Ga]Glu-NH-CO-NH-Lys(Ahx)-HBED-CC) is the most well studied PET imaging agent for detecting over expressed PSMA binding sites of tumors in humans. In an effort to provide new agents with improved characteristics for PET imaging, we report a novel [68 Ga]-Glu-NH-CO-NH-Lys(Ahx)-linker-HBED-CC conjugate with a novel O-(carboxymethyl)-L-tyrosine, as the linker group...
December 27, 2017: Nuclear Medicine and Biology
Jeffrey J Hsu, Jinxiu Lu, Soban Umar, Jason T Lee, Rajan Kulkarni, Yichen Ding, Chih-Chiang Chang, Tzung K Hsiai, Akishige Hokugo, Ioannis Gkouveris, Sotirios Tetradis, Ichiro Nishimura, Linda L Demer, Yin Tintut
Calcific aortic vasculopathy correlates with bone loss in osteoporosis in an age-independent manner. Prior work suggests that teriparatide, the bone anabolic treatment for postmenopausal osteoporosis, may inhibit onset of aortic calcification. Whether teriparatide affects progression of pre-existing aortic calcification, widespread among this patient population, is unknown. Female apolipoprotein E-deficient mice were aged for over one year to induce aortic calcification, treated for 4.5 weeks with daily injections of control vehicle (PBS), teriparatide 40 µg/kg (PTH40) or 400 µg/kg (PTH400), and assayed for aortic calcification by micro-computed tomography (microCT) before and after treatment...
February 16, 2018: American Journal of Physiology. Heart and Circulatory Physiology
Hui Liu, Hongjun Jin, Zhonghua Luo, Xuyi Yue, Xiang Zhang, Hubert Flores, Yi Su, Joel S Perlmutter, Zhude Tu
PET with Phosphodiesterase 10A (PDE10A) specific radioligands provide a noninvasive and quantitative imaging tool to access the expression of this enzyme in vivo under normal and diseased conditions. We recently reported two potent 18F-labeled PDE10A radioligands (18F-TZ19106B and 18F-TZ8110); initial evaluation in rats and nonhuman primates indicated stable metabolic profiles and excellent target-to-non-target ratio (striatum/cerebellum) for both tracers. Herein, we focused on in vivo characterization of 18F-TZ19106B and 18F-TZ8110 to identify a suitable radioligand for imaging PDE10A in vivo...
February 5, 2018: ACS Chemical Neuroscience
A Avendaño-Estrada, M A Ávila-Rodríguez
INTRODUCTION: Dopaminergic PET imaging is a useful tool to assess the dopaminergic integrity and to follow-up longitudinal studies. The aim of this study was to evaluate the reliability and reproducibility of different reference tissue-based methods to determine the non-displaceable binding potential (BPND ) as a quantitative measure of 11 C-DTBZ binding to the VMAT2 in rat striatum using cerebellum as reference region. METHODS: Eight healthy Wistar rats underwent two microPET scans at the age of 12 (test) and 20 weeks (retest)...
January 30, 2018: Synapse
Hushan Yuan, Moses Q Wilks, Marc D Normandin, Georges El Fakhri, Charalambos Kaittanis, Lee Josephson
Feraheme (FH) nanoparticles (NPs) have been used extensively for treatment of iron anemia (due to their slow release of ionic iron in acidic environments). In addition, injected FH NPs are internalized by monocytes and function as MRI biomarkers for the pathological accumulation of monocytes in disease. We have recently expanded these applications by radiolabeling FH NPs for positron emission tomography (PET) or single-photon emission computed tomography (SPECT) imaging using a heat-induced radiolabeling (HIR) strategy...
February 2018: Nature Protocols
Malgorzata Lipowska, Nashwa Jarkas, Ronald J Voll, Jonathon A Nye, Jeffrey Klenc, Mark M Goodman, Andrew T Taylor
INTRODUCTION: Our previous work demonstrated that the 99mTc renal tracer, 99mTc(CO)3(FEDA) (99mTc-1), has a rapid clearance comparable in rats to that of 131I-OIH, the radioactive gold standard for the measurement of effective renal plasma flow. The uncharged fluoroethyl pendant group of 99mTc-1 provides a route to the synthesis of a structurally analogous rhenium-tricarbonyl 18F renal imaging agent, Re(CO)3([18F]FEDA) (18F-1). Our goal was to develop an efficient one-step method for the preparation of 18F-1 and to compare its pharmacokinetic properties with those of 131I-OIH in rats...
December 27, 2017: Nuclear Medicine and Biology
Jason T Yoon, Mark S Longtine, Bernadette V Marquez-Nostra, Richard L Wahl
Radioimmunotherapies with monoclonal antibodies (mAbs) to the B-lymphocyte antigen 20 (CD20) are effective treatments for B-cell lymphomas, but United States Food and Drug Administration (FDA)-approved radioimmunotherapies exclusively use radiolabeled murine antibodies, potentially limiting re-dosing. The FDA recently approved two unlabeled anti-CD20 monoclonal antibodies, obinutizumab and ofatumumab, termed "next generation" as they are humanized (obinituzumab) or fully human (ofatumumab), thus potentially allowing a greater potential for re-dosing than with previous generation anti-CD20 antibodies, including rituximab (chimeric) and tositumumab (murine) which contain more murine peptide sequences...
January 18, 2018: Journal of Nuclear Medicine: Official Publication, Society of Nuclear Medicine
Jonatan A Snir, Mojmir Suchy, Geron A Bindseil, Michael Kovacs, Blaine A Chronik, Robert H E Hudson, Stephen H Pasternak, Robert Bartha
BACKGROUND: Early detection of Alzheimer's disease (AD) pathology is a serious challenge for both diagnosis and clinical trials. The aspartyl protease, Cathepsin D (CatD), is overexpressed in AD and could be a biomarker of disease. We have previously designed a unique contrast agent (CA) for dual-optical and magnetic resonance imaging of the activity of the CatD class of enzymes. OBJECTIVE: To compare the uptake and retention of a novel, more sensitive, and clinically-translatable 68Ga PET tracer targeting CatD activity in 5XFAD mice and non-Tg littermates...
2018: Journal of Alzheimer's Disease: JAD
Xiao Zhang, Chunbao Liu, Fan Hu, Yingying Zhang, Jing Wang, Yongheng Gao, Yaqun Jiang, Yongxue Zhang, Xiaoli Lan
Vascular cell adhesion molecule-1 (VCAM-1) is becoming an attractive candidate for targeting in tumor detection and therapy due to its involvement in tumorigenicity and metastasis. LY2409881, an IKK2 inhibitor, can trigger apoptosis of VCAM-1 positive melanoma cells. The aim of this study was to assess the use of the 68Ga-labeled single chain variable fragment (scFv) of VCAM-1 in detecting VCAM-1-positive tumor expression and monitoring the therapeutic effect of LY2409881. Melanoma cell lines, B16F10 and A375m, were sued as VCAM-1 overexpression and underexpression models, respectively...
January 8, 2018: Molecular Pharmaceutics
Futao Liu, Seok Rye Choi, Zhihao Zha, Karl Ploessl, Lin Zhu, Hank F Kung
INTRODUCTION: Vesicular monoamine transporters 2 (VMAT2) in the brain serve as transporter for packaging monoamine in vesicles for normal CNS neurotransmission. Several VMAT2 imaging agents, [11C]-(+)-DTBZ, dihydrotetrabenazine and [18F]FP-(+)-DTBZ (9-O-fluoropropyl-(+)-dihydro tetrabenazine, a.k.a. [18F]AV-133), are useful for studying the changes in brain function related to monoamine transmission by in vivo imaging. Deuterated analogs have been reported targeting VMAT2 binding sites...
December 6, 2017: Nuclear Medicine and Biology
Gemma M Dias, Caterina F Ramogida, Julie Rousseau, Nicholas A Zacchia, Cornelia Hoehr, Paul Schaffer, Kuo-Shyan Lin, François Bénard
INTRODUCTION: Zirconium-89 (89Zr, t1/2=78.4h) liquid target (LT) production offers an approach to introduce this positron-emitting isotope to cyclotron centres without the need for a separate solid target (ST) production set up. We compared the production, purification, and antibody radiolabeling yields of 89Zr-(LT) and 89Zr-(ST), and assessed the feasibility of 89Zr-(LT) for preclinical PET/CT. METHODS: 89Zr-(ST) production was performed with an 89Y foil on a TR 19 cyclotron at 13...
November 16, 2017: Nuclear Medicine and Biology
Zhi Zhang, Amar Jyoti, Bindu Balakrishnan, Monica Williams, Sarabdeep Singh, Diane C Chugani, Sujatha Kannan
BACKGROUND: Maternal infection is a risk factor for periventricular leukomalacia and cerebral palsy (CP) in neonates. We have previously demonstrated hypomyelination and motor deficits in newborn rabbits, as seen in patients with cerebral palsy, following maternal intrauterine endotoxin administration. This was associated with increased microglial activation, primarily involving the periventricular region (PVR). In this study we hypothesized that maternal intrauterine inflammation leads to a pro-inflammatory environment in the PVR that is associated with microglial activation in the first 2 postnatal weeks...
December 20, 2017: Neurobiology of Disease
Freja Bertelsen, Anne M Landau, Karina H Vase, Jan Jacobsen, Jørgen Scheel-Krüger, Arne Møller
γ-Aminobutyric acid (GABA) is the primary inhibitory neurotransmitter in the nervous system acting mainly through GABAA receptors. In the presence of high levels of GABA, an allosteric shift in the GABAA receptors can change the affinity of benzodiazepine (BZD) ligands. Valproic acid (VPA) is an anticonvulsant that enhances the level of endogenous GABA in the brain. The BZD ligand, Ro15-4513 has a high affinity for GABAA receptors containing the α5 subunit and can be used to investigate the GABA shift in the brains of living rats after VPA exposure...
December 16, 2017: Brain Research
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