Publications by authors named "Guie Gu"
Purpose: 4-F-Fluoro-m-hydroxyphenethylguanidine (F-4F-MHPG) and 3-F-fluoro-p-hydroxyphenethylguanidine (F-3F-PHPG) were developed for quantifying regional cardiac sympathetic nerve density using tracer kinetic analysis. The aim of this study was to evaluate their performance in cardiomyopathy patients.
Methods: Eight cardiomyopathy patients were scanned with F-4F-MHPG and F-3F-PHPG.
Improved synthesis of 4-[ F]fluoro-m-hydroxyphenethylguanidine using an iodonium ylide precursor.
J Labelled Comp Radiopharm
October 2019
Fluorine-18 labeled hydroxyphenethylguanidines were recently developed in our laboratory as a new class of PET radiopharmaceuticals for quantifying regional cardiac sympathetic nerve density in heart disease patients. Studies of 4-[ F]fluoro-m-hydroxyphenethylguanidine ([ F]4F-MHPG) and 3-[ F]fluoro-p-hydroxyphenethylguanidine ([ F]3F-PHPG) in human subjects have shown that these radiotracers can be used to generate high-resolution maps of regional sympathetic nerve density using the Patlak graphical method. Previously, these compounds were synthesized using iodonium salt precursors, which provided sufficient radiochemical yields for on-site clinical PET studies.
View Article and Find Full Text PDFFirst-in-Human Studies of [F] Fluorohydroxyphenethylguanidines.
Circ Cardiovasc Imaging
December 2018
Article Synopsis
- Disease-related damage to cardiac nerves increases the risk of sudden cardiac death, and new PET radiotracers were evaluated to measure sympathetic nerve density in the heart.
- The study involved normal subjects to test the effectiveness and safety of the new PET tracers, with results showing solid metrics for nerve density using Patlak graphical analysis.
- Both tracers provided excellent imaging of cardiac sympathetic nerves and were mainly eliminated through urinary pathways, indicating their potential for assessing cardiac health.
Article Synopsis
- Fluorine-18 labeled phenethylguanidines are being developed as radiotracers for PET imaging to assess cardiac sympathetic nerve density.
- The synthesis of these compounds involves a nucleophilic aromatic fluorination of a diaryliodonium salt precursor, leading to reliable production of two specific radiolabeled compounds, [F]4F-MHPG and [F]3F-PHPG, with good yields.
- Preclinical studies in nonhuman primates show that both tracers have comparable imaging properties and are being evaluated in first-in-human PET studies to potentially enhance diagnostic capabilities in heart disease.
Article Synopsis
- [(18)F]4F-MHPG is a new radiotracer designed for PET imaging to study cardiac sympathetic nerve density, showing promising kinetic properties.
- The automated synthesis process involves creating an intermediate compound using a unique precursor for effective fluorination.
- PET studies in rhesus macaque monkeys indicate that the tracer offers high-quality cardiac images with minimal interference from lung and liver uptake, and its effectiveness can be quantitatively assessed through pharmacological blocking with desipramine.
Article Synopsis
- Current cardiac sympathetic nerve radiotracers like (123)I-MIBG and (11)C-HED are too fast in their transport rates, making them ineffective for detecting mild nerve losses.
- The study focuses on (11)C-GMO, which has a slower transport rate and is stored in vesicles, aiming to assess its potential for accurately measuring nerve density in the heart.
- Results from PET studies show that (11)C-GMO's uptake is significantly slower than that of existing tracers and can reliably indicate reductions in nerve availability when influenced by the NET inhibitor desipramine.
Article Synopsis
- A new cardiac imaging agent, [(18)F]4F-MHPG, was developed to assess sympathetic nerve activity in the heart.
- Initial studies on rats showed that the uptake and retention of this agent in nerve cells were promising, similar to an earlier carbon-11 version.
- PET imaging in nonhuman primates demonstrated excellent image quality and suggest that [(18)F]4F-MHPG could improve the quantification of cardiac sympathetic nerve density compared to current methods.
Introduction: Most radiotracers for imaging of cardiac sympathetic innervation are substrates of the norepinephrine transporter (NET). The goal of this study was to characterize the NET transport kinetics and binding affinities of several sympathetic nerve radiotracers, including [(11)C]-(-)-meta-hydroxyephedrine, [(11)C]-(-)-epinephrine, and a series of [(11)C]-labeled phenethylguanidines under development in our laboratory. For comparison, the NET transport kinetics and binding affinities of some [(3)H]-labeled biogenic amines were also determined.
View Article and Find Full Text PDFThe Drosophila ninaB gene encodes a beta,beta-carotene-15,15'-oxygenase responsible for the centric cleavage of beta-carotene that produces the retinal chromophore of rhodopsin. The ninaD gene encodes a membrane receptor required for efficient use of beta-carotene. Despite their importance to the synthesis of visual pigment, we show that these genes are not active in the retina.
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