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Rossano S, Toyonaga T, Berg E, Lorence I, Fowles K, Nabulsi N, Ropchan J, Li S, Ye Y, Felchner Z, Kukis D, Huang Y, Benveniste H, Tarantal AF, Groman S, Carson RE. Imaging the fetal nonhuman primate brain with SV2A positron emission tomography (PET). Eur J Nucl Med Mol Imaging 2022; 49:3679-3691. [PMID: 35633376 PMCID: PMC9826644 DOI: 10.1007/s00259-022-05825-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2021] [Accepted: 04/26/2022] [Indexed: 01/11/2023]
Abstract
PURPOSE Exploring synaptic density changes during brain growth is crucial to understanding brain development. Previous studies in nonhuman primates report a rapid increase in synapse number between the late gestational period and the early neonatal period, such that synaptic density approaches adult levels by birth. Prenatal synaptic development may have an enduring impact on postnatal brain development, but precisely how synaptic density changes in utero are unknown because current methods to quantify synaptic density are invasive and require post-mortem brain tissue. METHODS We used synaptic vesicle glycoprotein 2A (SV2A) positron emission tomography (PET) radioligands [11C]UCB-J and [18F]Syn-VesT-1 to conduct the first assessment of synaptic density in the developing fetal brain in gravid rhesus monkeys. Eight pregnant monkeys were scanned twice during the third trimester at two imaging sites. Fetal post-mortem samples were collected near term in a subset of subjects to quantify SV2A density by Western blot. RESULTS Image-derived fetal brain SV2A measures increased during the third trimester. SV2A concentrations were greater in subcortical regions than in cortical regions at both gestational ages. Near term, SV2A density was higher in primary motor and visual areas than respective associative regions. Post-mortem quantification of SV2A density was significantly correlated with regional SV2A PET measures. CONCLUSION While further study is needed to determine the exact relationship of SV2A and synaptic density, the imaging paradigm developed in the current study allows for the effective in vivo study of SV2A development in the fetal brain.
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Affiliation(s)
- Samantha Rossano
- Department of Radiology and Biomedical Imaging, Yale PET Center, Yale School of Medicine, New Haven, CT, USA.
- Department of Biomedical Engineering, Yale University, New Haven, CT, USA.
| | - Takuya Toyonaga
- Department of Radiology and Biomedical Imaging, Yale PET Center, Yale School of Medicine, New Haven, CT, USA
| | - Eric Berg
- Department of Biomedical Engineering, University of California, Davis, CA, USA
| | - Isabella Lorence
- Department of Radiology and Biomedical Imaging, Yale PET Center, Yale School of Medicine, New Haven, CT, USA
| | - Krista Fowles
- Department of Radiology and Biomedical Imaging, Yale PET Center, Yale School of Medicine, New Haven, CT, USA
| | - Nabeel Nabulsi
- Department of Radiology and Biomedical Imaging, Yale PET Center, Yale School of Medicine, New Haven, CT, USA
| | - Jim Ropchan
- Department of Radiology and Biomedical Imaging, Yale PET Center, Yale School of Medicine, New Haven, CT, USA
| | - Songye Li
- Department of Radiology and Biomedical Imaging, Yale PET Center, Yale School of Medicine, New Haven, CT, USA
| | - Yunpeng Ye
- Department of Radiology and Biomedical Imaging, Yale PET Center, Yale School of Medicine, New Haven, CT, USA
| | - Zachary Felchner
- Department of Radiology and Biomedical Imaging, Yale PET Center, Yale School of Medicine, New Haven, CT, USA
| | - David Kukis
- Center for Molecular and Genomic Imaging, University of California, Davis, CA, USA
| | - Yiyun Huang
- Department of Radiology and Biomedical Imaging, Yale PET Center, Yale School of Medicine, New Haven, CT, USA
| | - Helene Benveniste
- Department of Anesthesiology, Yale School of Medicine, Yale University, New Haven, CT, USA
| | - Alice F Tarantal
- Departments of Pediatrics and Cell Biology and Human Anatomy, School of Medicine, and California National Primate Research Center, University of California, Davis, CA, USA
| | - Stephanie Groman
- Department of Psychiatry, Yale University, New Haven, CT, USA
- Department of Neuroscience, University of Minnesota, Minneapolis, MN, USA
| | - Richard E Carson
- Department of Radiology and Biomedical Imaging, Yale PET Center, Yale School of Medicine, New Haven, CT, USA
- Department of Biomedical Engineering, Yale University, New Haven, CT, USA
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Converse AK, Ahlers EO, Bryan TW, Hetue JD, Lake KA, Ellison PA, Engle JW, Barnhart TE, Nickles RJ, Williams PH, DeJesus OT. Mathematical modeling of positron emission tomography (PET) data to assess radiofluoride transport in living plants following petiolar administration. PLANT METHODS 2015; 11:18. [PMID: 25774208 PMCID: PMC4359769 DOI: 10.1186/s13007-015-0061-y] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/04/2014] [Accepted: 02/25/2015] [Indexed: 05/25/2023]
Abstract
BACKGROUND Ion transport is a fundamental physiological process that can be studied non-invasively in living plants with radiotracer imaging methods. Fluoride is a known phytotoxic pollutant and understanding its transport in plants after leaf absorption is of interest to those in agricultural areas near industrial sources of airborne fluoride. Here we report the novel use of a commercial, high-resolution, animal positron emission tomography (PET) scanner to trace a bolus of [(18)F]fluoride administered via bisected petioles of Brassica oleracea, an established model species, to simulate whole plant uptake of atmospheric fluoride. This methodology allows for the first time mathematical compartmental modeling of fluoride transport in the living plant. Radiotracer kinetics in the stem were described with a single-parameter free- and trapped-compartment model and mean arrival times at different stem positions were calculated from the free-compartment time-activity curves. RESULTS After initiation of administration at the bisected leaf stalk, [(18)F] radioactivity climbed for approximately 10 minutes followed by rapid washout from the stem and equilibration within leaves. Kinetic modeling of transport in the stem yielded a trapping rate of 1.5 +/- 0.3%/min (mean +/- s.d., n = 3), velocity of 2.2 +/- 1.1 cm/min, and trapping fraction of 0.8 +/- 0.5%/cm. CONCLUSION Quantitative assessment of physiologically meaningful transport parameters of fluoride in living plants is possible using standard positron emission tomography in combination with petiolar radiotracer administration. Movement of free fluoride was observed to be consistent with bulk flow in xylem, namely a rapid and linear change in position with respect to time. Trapping, likely in the apoplast, was observed. Future applications of the methods described here include studies of transport of other ions and molecules of interest in plant physiology.
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Affiliation(s)
| | - Elizabeth O Ahlers
- />T123 Waisman Center, University of Wisconsin-Madison, Madison, WI 53705 USA
| | - Tom W Bryan
- />Department of Plant Pathology, University of Wisconsin-Madison, Madison, WI 53705 USA
| | - Jackson D Hetue
- />Department of Plant Pathology, University of Wisconsin-Madison, Madison, WI 53705 USA
| | - Katherine A Lake
- />Department of Medical Physics, University of Wisconsin-Madison, Madison, WI 53705 USA
| | - Paul A Ellison
- />Department of Medical Physics, University of Wisconsin-Madison, Madison, WI 53705 USA
| | - Jonathan W Engle
- />Department of Medical Physics, University of Wisconsin-Madison, Madison, WI 53705 USA
| | - Todd E Barnhart
- />Department of Medical Physics, University of Wisconsin-Madison, Madison, WI 53705 USA
| | - Robert J Nickles
- />Department of Medical Physics, University of Wisconsin-Madison, Madison, WI 53705 USA
| | - Paul H Williams
- />Department of Plant Pathology, University of Wisconsin-Madison, Madison, WI 53705 USA
| | - Onofre T DeJesus
- />Department of Medical Physics, University of Wisconsin-Madison, Madison, WI 53705 USA
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Bartlett RM, Murali D, Nickles RJ, Barnhart TE, Holden JE, DeJesus OT. Assessment of fetal brain uptake of paraquat in utero using in vivo PET/CT imaging. Toxicol Sci 2011; 122:551-6. [PMID: 21546347 DOI: 10.1093/toxsci/kfr104] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
Prenatal in utero conditions are thought to play a role in the development of adult diseases including Parkinson's disease (PD). Paraquat is a common herbicide with chemical structure similar to 1-methyl-4-phenyl 1,2,3,6-tetrahydropyridine, a neurotoxin known to induce parkinsonism. In order to assess the role of in utero paraquat exposure in PD, uptake in maternal and fetal brains were measured using positron emission tomography (PET)/computed tomography (CT) imaging. Two anesthetized pregnant rhesus macaques in the late second trimester of pregnancy were given bolus iv injections of ¹¹C-paraquat, and whole-body PET/CT imaging was performed. Using maternal ventricular blood pool as the input function, the unidirectional influx rate constants (K(i)s), a measure of the irreversible transport of paraquat from plasma to brain, were calculated for the maternal and fetal brains using Patlak graphical analysis. Results indicate minimal uptake of paraquat by both maternal and fetal brains with average K(i)s of 0.0009 and 0.0016 per minute, respectively. The highest regional cerebral uptake in the maternal brain (0.0009% injected dose) was seen in the pineal gland, a structure known to lack a blood brain barrier. The finding of minimal paraquat uptake in maternal and fetal brains is similar to previous findings in adult male macaques and extends the contention that a single acute paraquat exposure, prenatally or postnatally, is unlikely to play a role in PD.
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Affiliation(s)
- Rachel M Bartlett
- Department of Medical Physics, School of Medicine and Public Health, University of Wisconsin, Madison, Wisconsin 53706, USA
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