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1.
Genome Biol Evol ; 16(5)2024 05 02.
Artículo en Inglés | MEDLINE | ID: mdl-38701021

RESUMEN

The genomes of plant and animal species are influenced by ancestral whole-genome duplication (WGD) events, which have profound impacts on the regulation and function of gene networks. To gain insight into the consequences of WGD events, we characterized the sequence conservation and expression patterns of ohnologs in the highly duplicated activin receptor signaling pathway in rainbow trout (RBT). The RBT activin receptor signaling pathway is defined by tissue-specific expression of inhibitors and ligands and broad expression of receptors and Co-Smad signaling molecules. Signaling pathway ligands exhibited shared expression, while inhibitors and Smad signaling molecules primarily express a single dominant ohnolog. Our findings suggest that gene function influences ohnolog evolution following duplication of the activin signaling pathway in RBT.


Asunto(s)
Evolución Molecular , Duplicación de Gen , Oncorhynchus mykiss , Transducción de Señal , Animales , Oncorhynchus mykiss/genética , Genoma , Activinas/metabolismo , Activinas/genética , Receptores de Activinas/genética , Receptores de Activinas/metabolismo
2.
Ecol Evol ; 13(4): e9994, 2023 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-37091557

RESUMEN

Salmonid fishes have emerged as a tractable model to study whole-genome duplications (WGDs) as this group has undergone four rounds of WGDs. While most of the salmonid genome has returned to a diploid state, a significant proportion of genes are maintained as duplicates and are referred to as ohnologs. The fact that much of the modern salmonid gene repertoire is comprised of ohnologs, while other genes have returned to their singleton state creates complications for genetic studies by obscuring homology relationships. The difficulty this creates is particularly prominent in Pacific salmonids belonging to genus Oncorhynchus who are the focus of intense genetics-based conservation and management efforts owing to the important ecological and cultural roles these fish play. To address this gap, we generated a homology guide for six species of Oncorhynchus with available genomes and used this guide to describe patterns of ohnolog retention and resolution. Overall, we find that ohnologs comprise approximately half of each species modern gene repertoires, which are functionally enriched for genes involved in DNA binding, while the less numerous singleton genes are heavily enriched in dosage-sensitive processes such as mitochondrial metabolism. Additionally, by reanalyzing published expression data from locally adapted strains of O. mykiss, we show that numerous ohnologs exhibit adaptive expression profiles; however, ohnologs are not more likely to display adaptive signatures than either paralogs or singletons. Finally, we demonstrate the utility of our homology guide by investigating the evolutionary relationship among genes highlighted as playing a role in salmonid life-history traits or gene editing targets.

3.
J Immunol Res ; 2022: 1737419, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-35097132

RESUMEN

Complement factor H (FH) is a key regulator of the alternative pathway of complement, in man and mouse. Earlier, our studies revealed that the absence of FH causes the C57BL6 mouse to become susceptible to chronic serum sickness (CSS) along with an increase in the renal infiltration of macrophages compared to controls. To understand if the increased recruitment of macrophages (Mϕs) to the kidney was driving inflammation and propagating injury, we examined the effect of Mϕ depletion with clodronate in FH knockout mice with CSS. Eight-week-old FHKO mice were treated with apoferritin (4 mg/mouse) for 5 wks and with either vehicle (PBS) or clodronate (50 mg/kg ip, 3 times/wk for the last 3 weeks). The administration of clodronate decreased monocytes and Mϕs in the kidneys by >80%. Kidney function assessed by BUN and albumin remained closer to normal on depletion of Mϕs. Clodronate treatment prevented the alteration in cytokines, TNFα and IL-6, and increase in gene expression of connective tissue growth factor (CTGF), TGFß-1, matrix metalloproteinase-9 (MMP9), fibronectin, laminin, and collagen in FHKO mice with CSS (P < 0.05). Clodronate treatment led to relative protection from immune complex- (IC-) mediated disease pathology during CSS as assessed by the significantly reduced glomerular pathology (GN) and extracellular matrix. Our results suggest that complement activation is one of the mechanism that regulates the macrophage landscape and thereby fibrosis. The exact mechanism remains to be deciphered. In brief, our data shows that Mϕs play a critical role in FH-dependent ICGN and Mϕ depletion reduces disease progression.


Asunto(s)
Glomerulonefritis/inmunología , Enfermedades del Complejo Inmune/inmunología , Riñón/metabolismo , Macrófagos/inmunología , Animales , Apoferritinas/administración & dosificación , Movimiento Celular , Ácido Clodrónico/administración & dosificación , Factor H de Complemento/metabolismo , Progresión de la Enfermedad , Fibrosis , Riñón/inmunología , Riñón/patología , Metaloproteinasa 9 de la Matriz/metabolismo , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados
4.
J Neuromuscul Dis ; 8(s2): S271-S281, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-34275905

RESUMEN

BACKGROUND: Duchenne muscular dystrophy is a degenerative muscle disease that results from impairment of the dystrophin gene. The disease causes progressive loss in muscle mass and function. OBJECTIVE: The anti-aging protein, α-klotho, has been implicated in the regulation of muscle regeneration. We previously discovered that mice harboring reduced α-klotho levels exhibited a decline in muscle strength and running endurance. METHOD: To investigate the ability of α-klotho to improve overall endurance in a dystrophin null murine model, we examined the voluntary wheel running performance of dystrophin-null, mdx4cv mice overexpressing an α-klotho transgene. RESULTS: As expected, compared to wild type, both male and female dystrophic mice exhibited reduced running ability that was characterized by shorter running duration and longer periods of rest between cycles of activity. While our results did not detect an improvement in running performance with α-klotho overexpression, we identified distinct differences in the running patterns between females and males from all mouse strains analyzed (i.e., mdx4cv, mdx4cv overexpressing α-klotho, α-klotho overexpressing, α-klotho hypomorph, and wild type). For all strains, male mice displayed significantly reduced voluntary running ability compared to females. Further analysis of the mdx4cv strains demonstrated that male mice ran for shorter lengths of time and took longer breaks. However, we did not identify gender-associated differences in the actual speed at which mdx4cv mice ran. CONCLUSION: Our data suggest key differences in the running capabilities of female and male mice, which are of particular relevance to studies of dystrophin-null mice.


Asunto(s)
Distrofina/metabolismo , Proteínas Klotho/metabolismo , Carrera , Animales , Femenino , Masculino , Ratones , Ratones Endogámicos mdx , Actividad Motora/fisiología , Fuerza Muscular , Músculo Esquelético/fisiopatología , Distrofia Muscular Animal/metabolismo , Distrofia Muscular de Duchenne/fisiopatología
8.
Jt Comm J Qual Patient Saf ; 46(9): 524-530, 2020 09.
Artículo en Inglés | MEDLINE | ID: mdl-32682692

RESUMEN

BACKGROUND: The objective of this study was to determine if anesthesia providers can accurately estimate the cost of commonly used medications, supplies, and blood products. METHODS: This study was conducted between April and June 2019 at an academic tertiary care hospital. Anesthesia providers (certified registered nurse anesthetists [CRNAs], residents, and fellows/attendings) were surveyed on their knowledge of the cost of commonly used therapies. Items were sorted into 12 categories: opioids, non-opioid analgesia, vasopressors, hypertension medications, antibiotics, neuromuscular blockers, reversals, anesthetics, supplies, kits, blood products, and blood-related products. Estimates were considered to be accurate if the median cost differed from the average wholesale price by < 25%, moderately inaccurate if between 25% and 50%, and severely inaccurate if by > 50%. RESULTS: A total of 107 surveys (CRNAs: 25, residents: 36, fellows/attendings: 46) were returned. The percentage of total items accurately estimated for cost was low (22% for all providers), and was not different between provider types (27% for CRNAs, 23% for residents, 20% for fellows/attendings; p = 0.69). The percentage of items with severe inaccuracies in cost estimation was high and was not different between provider types (56% for CRNAs, 60% for residents, 50% for fellows/attendings; p = 0.53). Rates of under- and overestimation varied widely, with greatest underestimation for vasopressors and blood-related products, and greatest overestimation for non-opioid analgesia and antibiotics. Low- and high-cost category items tended to be overestimated and underestimated, respectively (p < 0.0001). CONCLUSION: The majority of anesthesia providers have poor knowledge of cost. These findings suggest that cost awareness interventions may be necessary for promoting high-value health care.


Asunto(s)
Anestesia , Enfermeras Anestesistas , Humanos , Encuestas y Cuestionarios
9.
Proc Natl Acad Sci U S A ; 117(26): 15172-15181, 2020 06 30.
Artículo en Inglés | MEDLINE | ID: mdl-32532924

RESUMEN

Hu11B6 is a monoclonal antibody that internalizes in cells expressing androgen receptor (AR)-regulated prostate-specific enzyme human kallikrein-related peptidase 2 (hK2; KLK2). In multiple rodent models, Actinium-225-labeled hu11B6-IgG1 ([225Ac]hu11B6-IgG1) has shown promising treatment efficacy. In the present study, we investigated options to enhance and optimize [225Ac]hu11B6 treatment. First, we evaluated the possibility of exploiting IgG3, the IgG subclass with superior activation of complement and ability to mediate FC-γ-receptor binding, for immunotherapeutically enhanced hK2 targeted α-radioimmunotherapy. Second, we compared the therapeutic efficacy of a single high activity vs. fractionated activity. Finally, we used RNA sequencing to analyze the genomic signatures of prostate cancer that progressed after targeted α-therapy. [225Ac]hu11B6-IgG3 was a functionally enhanced alternative to [225Ac]hu11B6-IgG1 but offered no improvement of therapeutic efficacy. Progression-free survival was slightly increased with a single high activity compared to fractionated activity. Tumor-free animals succumbing after treatment revealed no evidence of treatment-associated toxicity. In addition to up-regulation of canonical aggressive prostate cancer genes, such as MMP7, ETV1, NTS, and SCHLAP1, we also noted a significant decrease in both KLK3 (prostate-specific antigen ) and FOLH1 (prostate-specific membrane antigen) but not in AR and KLK2, demonstrating efficacy of sequential [225Ac]hu11B6 in a mouse model.


Asunto(s)
Actinio/uso terapéutico , Inmunoconjugados/uso terapéutico , Antígeno Prostático Específico/inmunología , Neoplasias de la Próstata/terapia , Calicreínas de Tejido/metabolismo , Partículas alfa , Animales , Biomarcadores de Tumor , Humanos , Masculino , Ratones , Ratones Desnudos , Neoplasias Experimentales/terapia
10.
Conserv Biol ; 34(1): 54-65, 2020 02.
Artículo en Inglés | MEDLINE | ID: mdl-30693970

RESUMEN

As the conservation challenges increase, new approaches are needed to help combat losses in biodiversity and slow or reverse the decline of threatened species. Genome-editing technology is changing the face of modern biology, facilitating applications that were unimaginable only a decade ago. The technology has the potential to make significant contributions to the fields of evolutionary biology, ecology, and conservation, yet the fear of unintended consequences from designer ecosystems containing engineered organisms has stifled innovation. To overcome this gap in the understanding of what genome editing is and what its capabilities are, more research is needed to translate genome-editing discoveries into tools for ecological research. Emerging and future genome-editing technologies include new clustered regularly interspaced short palindromic repeats (CRISPR) targeted sequencing and nucleic acid detection approaches as well as species genetic barcoding and somatic genome-editing technologies. These genome-editing tools have the potential to transform the environmental sciences by providing new noninvasive methods for monitoring threatened species or for enhancing critical adaptive traits. A pioneering effort by the conservation community is required to apply these technologies to real-world conservation problems.


Transformación de la Ecología y la Biología de la Conservación por medio de la Edición Genómica Resumen Conforme aumentan los retos de conservación, se necesitan nuevas estrategias para ayudar a combatir las pérdidas de biodiversidad y para disminuir o revertir la declinación de especies. La tecnología de edición genómica está cambiando el rostro de la biología moderna, facilitando aplicaciones que eran inimaginables hace una década. Esta tecnología tiene el potencial de contribuir significativamente en los campos de la biología evolutiva, la ecología y la conservación, aun así, el miedo a las consecuencias accidentales de los ecosistemas planeados que contienen organismos diseñados ha sofocado a la innovación. Para sobreponerse a este vacío en el entendimiento de lo que es la edición genómica y cuáles son sus capacidades se requiere de mayor investigación para traducir los descubrimientos de la edición genómica a herramientas para la investigación ecológica. Las tecnologías de edición genómica emergentes y futuras incluyen nuevas estrategias CRISPR enfocadas en la secuenciación y detección de ácidos nucleicos, así como tecnologías de definición del código de barras genético de las especies y de edición somática de genes. Estas herramientas de edición genómica tienen el potencial para transformar las ciencias ambientales al proporcionar nuevos métodos no invasivos para el monitoreo de especies amenazadas o para mejorar las características adaptativas más importantes. Se requiere de un esfuerzo vanguardista por parte de la comunidad conservadora para aplicar esta tecnología a los problemas de conservación en el mundo real.


Asunto(s)
Sistemas CRISPR-Cas , Edición Génica , Repeticiones Palindrómicas Cortas Agrupadas y Regularmente Espaciadas , Conservación de los Recursos Naturales , Ecosistema
11.
Mol Imaging Biol ; 22(2): 256-264, 2020 04.
Artículo en Inglés | MEDLINE | ID: mdl-31240531

RESUMEN

In light of the United States Food and Drug Administration (FDA) requirement of 21 CFR 212 current Good Manufacturing Practice (cGMP) for FDA-approved position emission tomography (PET) drugs, the University of California Los Angeles (UCLA) Biomedical Cyclotron (BMC) transformed from a pre-cGMP era academic cyclotron and radiochemistry facility to a current cGMP-compliant PET drug manufacturer. In this article, we share the financial and regulatory compliance aspects of the "transformation" required to develop a sustainable quality system to support the production of two PET drugs under Abbreviated New Drug Applications (ANDAs).


Asunto(s)
Industria Farmacéutica/normas , Regulación y Control de Instalaciones/normas , Adhesión a Directriz , Tomografía de Emisión de Positrones/normas , Radioquímica/métodos , California , Ciclotrones , Aprobación de Drogas , Humanos , Control de Calidad , Radiofármacos , Estados Unidos , United States Food and Drug Administration , Universidades
12.
Front Mar Sci ; 62019 Aug 06.
Artículo en Inglés | MEDLINE | ID: mdl-31534948

RESUMEN

There is a growing need for operational oceanographic predictions in both the Arctic and Antarctic polar regions. In the former, this is driven by a declining ice cover accompanied by an increase in maritime traffic and exploitation of marine resources. Oceanographic predictions in the Antarctic are also important, both to support Antarctic operations and also to help elucidate processes governing sea ice and ice shelf stability. However, a significant gap exists in the ocean observing system in polar regions, compared to most areas of the global ocean, hindering the reliability of ocean and sea ice forecasts. This gap can also be seen from the spread in ocean and sea ice reanalyses for polar regions which provide an estimate of their uncertainty. The reduced reliability of polar predictions may affect the quality of various applications including search and rescue, coupling with numerical weather and seasonal predictions, historical reconstructions (reanalysis), aquaculture and environmental management including environmental emergency response. Here, we outline the status of existing near-real time ocean observational efforts in polar regions, discuss gaps, and explore perspectives for the future. Specific recommendations include a renewed call for open access to data, especially real-time data, as a critical capability for improved sea ice and weather forecasting and other environmental prediction needs. Dedicated efforts are also needed to make use of additional observations made as part of the Year of Polar Prediction (YOPP; 2017-2019) to inform optimal observing system design. To provide a polar extension to the Argo network, it is recommended that a network of ice-borne sea ice and upper-ocean observing buoys be deployed and supported operationally in ice-covered areas together with autonomous profiling floats and gliders (potentially with ice detection capability) in seasonally ice covered seas. Finally, additional efforts to better measure and parameterize surface exchanges in polar regions are much needed to improve coupled environmental prediction.

13.
Mol Ecol Resour ; 19(5): 1103-1105, 2019 09.
Artículo en Inglés | MEDLINE | ID: mdl-31560843

RESUMEN

The accelerating pace of scientific discovery is being driven by the development of transformative technologies that are expanding traditional scientific boundaries. In ecology, the concept that ecosystem structure can be monitored through the stew of genetic material released into the environment by local organisms is now a highly active area of research. At the same time that the use of environmental DNA (eDNA) has gained popularity in ecology, CRISPR genome editing technology has been revolutionizing organismal biology and the biomedical sciences. In a From the Cover article in this issue of Molecular Ecology Resources, Williams et al. (2019) report about the fusion of CRISPR technology with molecular ecology to improve the in situ processing capabilities of eDNA applications. Piloting this new CRISPR technology on aquatic systems, the authors describe tools to accurately identify the presence of Atlantic salmon (Salmo salar) from eDNA, using conditions that are highly amenable to implementation in the field. This overcomes a major barrier restricting the use of eDNA, opening a door to expanded use of the technology in ecological research.


Asunto(s)
ADN Ambiental , Ecosistema , Biodiversidad , Repeticiones Palindrómicas Cortas Agrupadas y Regularmente Espaciadas , Ecología
15.
Hum Gene Ther ; 30(7): 814-828, 2019 07.
Artículo en Inglés | MEDLINE | ID: mdl-30793977

RESUMEN

This study identified 35 new sites for targeted transgene insertion that have the potential to serve as new human genomic "safe harbor" sites (SHS). SHS potential for these 35 sites, located on 16 chromosomes, including both arms of the human X chromosome, and for the existing human SHS AAVS1, hROSA26, and CCR5 was assessed using eight different desirable, widely accepted criteria for SHS verifiable with human genomic data. Three representative newly identified sites on human chromosomes 2 and 4 were then experimentally validated by in vitro and in vivo cleavage-sensitivity tests, and analyzed for population-level and cell line-specific sequence variants that might confound site targeting. The highly ranked site on chromosome 4 (SHS231) was further characterized by targeted homology-dependent and -independent transgene insertion and expression in different human cell lines. The structure and fidelity of transgene insertions at this site were confirmed, together with analyses that demonstrated stable expression and function of transgene-encoded proteins, including fluorescent protein markers, selectable marker cassettes, and Cas9 protein variants. SHS-integrated transgene-encoded Cas9 proteins were shown to be capable of introducing a large (17 kb) gRNA-specified deletion in the PAX3/FOXO1 fusion oncogene in human rhabdomyosarcoma cells and as a Cas9-VPR fusion protein to upregulate expression of the muscle-specific transcription factor MYF5 in human rhabdomyosarcoma cells. An engineering "toolkit" was developed to enable easy use of the most extensively characterized of these new human sites, SHS231, located on the proximal long arm of chromosome 4. The target sites identified here have the potential to serve as additional human SHS to enable basic and clinical gene editing and genome-engineering applications.


Asunto(s)
Cromosomas Humanos , Mutagénesis Insercional , Transgenes , Secuencia de Bases , Sistemas CRISPR-Cas , Línea Celular , Puntos de Rotura del Cromosoma , Edición Génica , Expresión Génica , Técnicas de Sustitución del Gen , Marcación de Gen , Sitios Genéticos , Genoma Humano , Mapeo Geográfico , Humanos
16.
J Nucl Cardiol ; 26(6): 2018-2030, 2019 12.
Artículo en Inglés | MEDLINE | ID: mdl-30488323

RESUMEN

The objectives of this study were to evaluate radiation dosimetry, biodistribution, human safety, and tolerability of 18F-labeled flurpiridaz (Flurpiridaz) in normal subjects undergoing rest and separate-day exercise or adenosine pharmacological stress PET imaging. METHODS: 12 normal subjects were injected with 58.5 to 121 MBq (1.58 to 3.27 mCi) of Flurpiridaz intravenously at rest on Day 1 and 57 to 171 MBq (1.54 to 4.61 mCi) during stress on Day 2. Sequential whole-body imaging was performed for 5 hours. Blood samples were collected for up to 8 hours. RESULTS: The heart wall received the largest mean absorbed dose with both exercise and adenosine stresses. The mean effective dose was 0.054 rem/mCi (0.015 mSv/MBq) with exercise and 0.069 rem/mCi (0.019 mSv/MBq) with adenosine pharmacological stress. The maximum dose that may be administered without exceeding 1 rem (10 mSv) effective dose was 19 mCi (685 MBq) for exercise and 15 mCi (539 MBq) for adenosine pharmacological stress. There were no drug-related adverse events, and the tracer was well tolerated in all subjects. CONCLUSION: Based on radiation dosimetry, biodistribution, and safety observations, 18F-labeled flurpiridaz is found suitable for clinical PET myocardial perfusion imaging in conjunction with either exercise or pharmacological stress testing.


Asunto(s)
Adenosina/farmacología , Ejercicio Físico , Tomografía de Emisión de Positrones , Piridazinas/farmacocinética , Radiometría/métodos , Adulto , Prueba de Esfuerzo , Femenino , Voluntarios Sanos , Humanos , Masculino , Imagen de Perfusión Miocárdica , Seguridad del Paciente , Radiofármacos/farmacocinética , Imagen de Cuerpo Entero , Adulto Joven
17.
Mol Ther Oncolytics ; 11: 52-61, 2018 Dec 21.
Artículo en Inglés | MEDLINE | ID: mdl-30364635

RESUMEN

Aberrant activation of the receptor tyrosine kinase-mediated RAS signaling cascade is the primary driver of embryonal rhabdomyosarcoma (ERMS), a pediatric cancer characterized by a block in myogenic differentiation. To investigate the cellular function of activated RAS signaling in regulating the growth and differentiation of ERMS cells, we genetically ablated activated RAS oncogenes with high-efficiency genome-editing technology. Knockout of NRAS in CRISPR-inducible ERMS xenograft models resulted in near-complete tumor regression through a combination of cell death and myogenic differentiation. Utilizing this strategy for therapeutic RAS targeting in ERMS, we developed a recombinant oncolytic myxoma virus (MYXV) engineered with CRISPR/Cas9 gene-editing capability. Treatment of pre-clinical human ERMS tumor xenografts with an NRAS-targeting version of this MYXV significantly reduced tumor growth and increased overall survival. Our data suggest that targeted gene-editing cancer therapies have promising translational applications, especially with improvements to gene-targeting specificity and oncolytic vector technology.

18.
Cancer Cell ; 33(5): 905-921.e5, 2018 05 14.
Artículo en Inglés | MEDLINE | ID: mdl-29763624

RESUMEN

Altered metabolism is a hallmark of cancer growth, forming the conceptual basis for development of metabolic therapies as cancer treatments. We performed in vivo metabolic profiling and molecular analysis of lung squamous cell carcinoma (SCC) to identify metabolic nodes for therapeutic targeting. Lung SCCs adapt to chronic mTOR inhibition and suppression of glycolysis through the GSK3α/ß signaling pathway, which upregulates glutaminolysis. Phospho-GSK3α/ß protein levels are predictive of response to single-therapy mTOR inhibition while combinatorial treatment with the glutaminase inhibitor CB-839 effectively overcomes therapy resistance. In addition, we identified a conserved metabolic signature in a broad spectrum of hypermetabolic human tumors that may be predictive of patient outcome and response to combined metabolic therapies targeting mTOR and glutaminase.


Asunto(s)
Bencenoacetamidas/administración & dosificación , Compuestos de Boro/administración & dosificación , Carcinoma de Células Escamosas/metabolismo , Glutamina/metabolismo , Glicina/análogos & derivados , Glucógeno Sintasa Quinasa 3/metabolismo , Neoplasias Pulmonares/metabolismo , Tiadiazoles/administración & dosificación , Animales , Bencenoacetamidas/farmacología , Compuestos de Boro/farmacología , Carcinoma de Células Escamosas/tratamiento farmacológico , Carcinoma de Células Escamosas/genética , Línea Celular Tumoral , Proliferación Celular/efectos de los fármacos , Supervivencia Celular/efectos de los fármacos , Resistencia a Antineoplásicos/efectos de los fármacos , Regulación Neoplásica de la Expresión Génica/efectos de los fármacos , Glicina/administración & dosificación , Glicina/farmacología , Glucólisis , Humanos , Antígeno Ki-67/genética , Antígeno Ki-67/metabolismo , Neoplasias Pulmonares/tratamiento farmacológico , Neoplasias Pulmonares/genética , Ratones , Trasplante de Neoplasias , Transducción de Señal/efectos de los fármacos , Tiadiazoles/farmacología
19.
Commun Chem ; 1(1)2018.
Artículo en Inglés | MEDLINE | ID: mdl-34291178

RESUMEN

Positron emission tomography (PET) is a molecular diagnostic imaging technology to quantitatively visualize biological processes in vivo. For many applications, including imaging of low tissue density targets (e.g. neuroreceptors), imaging in small animals, and evaluation of novel tracers, the injected PET tracer must be produced with high molar activity to ensure low occupancy of biological targets and avoid pharmacologic effects. Additionally, high molar activity is essential for tracers with lengthy syntheses or tracers transported to distant imaging sites. We show that radiosynthesis of PET tracers in microliter volumes instead of conventional milliliter volumes results in substantially increased molar activity, and we identify the most relevant variables affecting this parameter. Furthermore, using the PET tracer [18F]fallypride, we illustrate that molar activity can have a significant impact on biodistribution. With full automation, microdroplet platforms could provide a means for radiochemists to routinely, conveniently, and safely produce PET tracers with high molar activity.

20.
Proc Natl Acad Sci U S A ; 114(43): 11309-11314, 2017 10 24.
Artículo en Inglés | MEDLINE | ID: mdl-29073049

RESUMEN

New radiolabeled probes for positron-emission tomography (PET) are providing an ever-increasing ability to answer diverse research and clinical questions and to facilitate the discovery, development, and clinical use of drugs in patient care. Despite the high equipment and facility costs to produce PET probes, many radiopharmacies and radiochemistry laboratories use a dedicated radiosynthesizer to produce each probe, even if the equipment is idle much of the time, to avoid the challenges of reconfiguring the system fluidics to switch from one probe to another. To meet growing demand, more cost-efficient approaches are being developed, such as radiosynthesizers based on disposable "cassettes," that do not require reconfiguration to switch among probes. However, most cassette-based systems make sacrifices in synthesis complexity or tolerated reaction conditions, and some do not support custom programming, thereby limiting their generality. In contrast, the design of the ELIXYS FLEX/CHEM cassette-based synthesizer supports higher temperatures and pressures than other systems while also facilitating flexible synthesis development. In this paper, the syntheses of 24 known PET probes are adapted to this system to explore the possibility of using a single radiosynthesizer and hot cell for production of a diverse array of compounds with wide-ranging synthesis requirements, alongside synthesis development efforts. Most probes were produced with yields and synthesis times comparable to literature reports, and because hardware modification was unnecessary, it was convenient to frequently switch among probes based on demand. Although our facility supplies probes for preclinical imaging, the same workflow would be applicable in a clinical setting.


Asunto(s)
Radioisótopos de Flúor/química , Radioquímica/métodos , Radiofármacos/síntesis química , Tomografía de Emisión de Positrones/métodos , Radiofármacos/química
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