scholarly journals Macrophage and Astrocyte Populations in Relation to [3H]PK 11195 Binding in Rat Cerebral Cortex following a Local Ischaemic Lesion

1991 ◽  
Vol 11 (2) ◽  
pp. 314-322 ◽  
Author(s):  
Ralph Myers ◽  
Luisa G. Manjil ◽  
Beulah M. Cullen ◽  
Gary W. Price ◽  
Richard S. J. Frackowiak ◽  
...  
Keyword(s):  
Human Brain ◽  
Time Intervals ◽  
Positron Emission ◽  
Separate Region ◽  
Peripheral Type ◽  
Ischaemic Lesion ◽  
The Relationship ◽  
Specific Ligand

PK 11195 is a selective and specific ligand for the peripheral-type benzodiazepine binding site. Its potential for in vivo visualisation of lesioned human brain using positron emission tomography (PET) is currently being assessed. The present study examines the relationship between the temporal development of a local ischaemic lesion with its associated cell populations and the binding of [3H]PK 11195 in rat brain. Unilateral cortical infarcts were induced using the photosensitive dye Rose Bengal. At time intervals from 1 to 7 days after lesioning, the localisation of [3H]PK 11195 binding was determined using in vivo and in vitro autoradiography. Sections adjacent to those used for autoradiography were processed for immunohistochemistry using glial fibrillary acidic protein for astrocytes and ED-1 for macrophages. The results show that the binding of [3H]PK 11195 correlates in both time and spatial localisation with the appearance of macrophages around the lesion. Reactive astrocytes, although present, occupy a separate region in the tissue surrounding the lesion and lie outside the region defined by the [3H]PK 11195 binding. We conclude that the [3H]PK 11195 signal associated with this ischaemic lesion originates primarily from binding to macrophages and that [C]PK 11195 could be used for imaging acute inflammatory response in human brain using PET.

scholarly journals Combining PET Biodistribution and Equilibrium Dialysis Assays to Assess the Free Brain Concentration and BBB Transport of CNS Drugs

2012 ◽  
Vol 32 (5) ◽  
pp. 874-883 ◽  
Author(s):  
Roger N Gunn ◽  
Scott G Summerfield ◽  
Cristian A Salinas ◽  
Kevin D Read ◽  
Qi Guo ◽  
...  
Keyword(s):  
Drug Development ◽  
Human Brain ◽  
Concentration Gradient ◽  
Equilibrium Dialysis ◽  
Active Efflux ◽  
Brain Concentration ◽  
Drug Candidates ◽  
Positron Emission

The passage of drugs in and out of the brain is controlled by the blood—brain barrier (BBB), typically, using either passive diffusion across a concentration gradient or active transport via a protein carrier. In-vitro and preclinical measurements of BBB penetration do not always accurately predict the in-vivo situation in humans. Thus, the ability to assay the concentration of novel drug candidates in the human brain in vivo provides valuable information for derisking of candidate molecules early in drug development. Here, positron emission tomography (PET) measurements are combined with in-vitro equilibrium dialysis assays to enable assessment of transport and estimation of the free brain concentration in vivo. The PET and equilibrium dialysis data were obtained for 36 compounds in the pig. Predicted P-glycoprotein (P-gp) status of the compounds was consistent with the PET/equilibrium dialysis results. In particular, Loperamide, a well-known P-gp substrate, exhibited a significant concentration gradient consistent with active efflux and after inhibition of the P-gp process the gradient was removed. The ability to measure the free brain concentration and assess transport of novel compounds in the human brain with combined PET and equilibrium dialysis assays can be a useful tool in central nervous system (CNS) drug development.

Ultrastructural Correlations between Clonal Human Tumor Colonies and in Vivo Neoplasms

1982 ◽  
Vol 40 ◽  
pp. 210-211
Author(s):  
M.J. Murphy ◽  
R.R. Price ◽  
J.C. Sloman
Keyword(s):  
Cultured Cells ◽  
Human Tumor ◽  
Cell Type ◽  
Tumor Mass ◽  
Initial Cell ◽  
Cloning Assay ◽  
Human Tumor Cloning ◽  
The Relationship

The in vitro human tumor cloning assay originally described by Salmon and Hamburger has been applied recently to the investigation of differential anti-tumor drug sensitivities over a broad range of human neoplasms. A major problem in the acceptance of this technique has been the question of the relationship between the cultured cells and the original patient tumor, i.e., whether the colonies that develop derive from the neoplasm or from some other cell type within the initial cell population. A study of the ultrastructural morphology of the cultured cells vs. patient tumor has therefore been undertaken to resolve this question. Direct correlation was assured by division of a common tumor mass at surgical resection, one biopsy being fixed for TEM studies, the second being rapidly transported to the laboratory for culture.

scholarly journals Development of a blood sample detector for multi-tracer positron emission tomography using gamma spectroscopy

2019 ◽  
Vol 6 (1) ◽  
Author(s):  
Carlos Velasco ◽  
Adriana Mota-Cobián ◽  
Jesús Mateo ◽  
Samuel España
Keyword(s):  
Positron Emission Tomography ◽  
Blood Sample ◽  
Pet Imaging ◽  
Spectroscopic Analysis ◽  
Gamma Spectroscopy ◽  
Emission Tomography ◽  
Blood Samples ◽  
Positron Emission

Abstract Background Multi-tracer positron emission tomography (PET) imaging can be accomplished by applying multi-tracer compartment modeling. Recently, a method has been proposed in which the arterial input functions (AIFs) of the multi-tracer PET scan are explicitly derived. For that purpose, a gamma spectroscopic analysis is performed on blood samples manually withdrawn from the patient when at least one of the co-injected tracers is based on a non-pure positron emitter. Alternatively, these blood samples required for the spectroscopic analysis may be obtained and analyzed on site by an automated detection device, thus minimizing analysis time and radiation exposure of the operating personnel. In this work, a new automated blood sample detector based on silicon photomultipliers (SiPMs) for single- and multi-tracer PET imaging is presented, characterized, and tested in vitro and in vivo. Results The detector presented in this work stores and analyzes on-the-fly single and coincidence detected events. A sensitivity of 22.6 cps/(kBq/mL) and 1.7 cps/(kBq/mL) was obtained for single and coincidence events respectively. An energy resolution of 35% full-width-half-maximum (FWHM) at 511 keV and a minimum detectable activity of 0.30 ± 0.08 kBq/mL in single mode were obtained. The in vivo AIFs obtained with the detector show an excellent Pearson’s correlation (r = 0.996, p < 0.0001) with the ones obtained from well counter analysis of discrete blood samples. Moreover, in vitro experiments demonstrate the capability of the detector to apply the gamma spectroscopic analysis on a mixture of 68Ga and 18F and separate the individual signal emitted from each one. Conclusions Characterization and in vivo evaluation under realistic experimental conditions showed that the detector proposed in this work offers excellent sensibility and stability. The device also showed to successfully separate individual signals emitted from a mixture of radioisotopes. Therefore, the blood sample detector presented in this study allows fully automatic AIFs measurements during single- and multi-tracer PET studies.

scholarly journals Effect of ethanol and cocaine on [11C]MPC-6827 uptake in SH-SY5Y cells

2021 ◽  
Author(s):  
Naresh Damuka ◽  
Miranda Orr ◽  
Paul W. Czoty ◽  
Jeffrey L. Weiner ◽  
Thomas J. Martin ◽  
...  
Keyword(s):  
Mechanism Of Action ◽  
Ex Vivo ◽  
Neuroblastoma Cells ◽  
Proper Function ◽  
Brain Functions ◽  
Biodistribution Studies ◽  
Positron Emission ◽  
Vitro Binding

AbstractMicrotubules (MTs) are structural units in the cytoskeleton. In brain cells they are responsible for axonal transport, information processing, and signaling mechanisms. Proper function of these processes is critical for healthy brain functions. Alcohol and substance use disorders (AUD/SUDs) affects the function and organization of MTs in the brain, making them a potential neuroimaging marker to study the resulting impairment of overall neurobehavioral and cognitive processes. Our lab reported the first brain-penetrant MT-tracking Positron Emission Tomography (PET) ligand [11C]MPC-6827 and demonstrated its in vivo utility in rodents and non-human primates. To further explore the in vivo imaging potential of [11C]MPC-6827, we need to investigate its mechanism of action. Here, we report preliminary in vitro binding results in SH-SY5Y neuroblastoma cells exposed to ethanol (EtOH) or cocaine in combination with multiple agents that alter MT stability. EtOH and cocaine treatments increased MT stability and decreased free tubulin monomers. Our initial cell-binding assay demonstrated that [11C]MPC-6827 may have high affinity to free/unbound tubulin units. Consistent with this mechanism of action, we observed lower [11C]MPC-6827 uptake in SH-SY5Y cells after EtOH and cocaine treatments (e.g., fewer free tubulin units). We are currently performing in vivo PET imaging and ex vivo biodistribution studies in rodent and nonhuman primate models of AUD and SUDs and Alzheimer's disease.

scholarly journals Role of interleukins in the pathogenesis of pulmonary fibrosis

2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Yi Xin She ◽  
Qing Yang Yu ◽  
Xiao Xiao Tang
Keyword(s):  
Pulmonary Fibrosis ◽  
Therapeutic Strategy ◽  
Future Directions ◽  
Regulation Mechanisms ◽  
Underlying Mechanisms ◽  
Multiple Cells ◽  
The Relationship

AbstractInterleukins, a group of cytokines participating in inflammation and immune response, are proved to be involved in the formation and development of pulmonary fibrosis. In this article, we reviewed the relationship between interleukins and pulmonary fibrosis from the clinical, animal, as well as cellular levels, and discussed the underlying mechanisms in vivo and in vitro. Despite the effects of interleukin-targeted treatment on experimental pulmonary fibrosis, clinical applications are lacking and unsatisfactory. We conclude that intervening in one type of interleukins with similar functions in IPF may not be enough to stop the development of fibrosis as it involves a complex network of regulation mechanisms. Intervening interleukins combined with other existing therapy or targeting interleukins affecting multiple cells/with different functions at the same time may be one of the future directions. Furthermore, the intervention time is critical as some interleukins play different roles at different stages. Further elucidation on these aspects would provide new perspectives on both the pathogenesis mechanism, as well as the therapeutic strategy and drug development.

scholarly journals Optimised GMP-compliant production of [18F]DPA-714 on the Trasis AllinOne module

2021 ◽  
Vol 6 (1) ◽  
Author(s):  
Klaudia A. Cybulska ◽  
Vera Bloemers ◽  
Lars R. Perk ◽  
Peter Laverman
Keyword(s):  
Significant Degree ◽  
Translocator Protein ◽  
Positron Emission ◽  
Leaving Group ◽  
Inflammatory Processes ◽  
Single Production ◽  
Translocator Protein 18 Kda ◽  
Radiochemical Yields ◽  
Specific Ligand

Abstract Background The translocator protein 18 kDa is recognised as an important biomarker for neuroinflammation due to its soaring expression in microglia. This process is common for various neurological disorders. DPA-714 is a potent TSPO-specific ligand which found its use in Positron Emission Tomography following substitution of fluorine-19 with fluorine-18, a positron-emitting radionuclide. [18F]DPA-714 enables visualisation of inflammatory processes in vivo non-invasively. Radiolabelling of this tracer is well described in literature, including validation for clinical use. Here, we report significant enhancements to the process which resulted in the design of a fully GMP-compliant robust synthesis of [18F]DPA-714 on a popular cassette-based system, Trasis AllinOne, boosting reliability, throughput, and introducing a significant degree of simplicity. Results [18F]DPA-714 was synthesised using the classic nucleophilic aliphatic substitution on a good leaving group, tosylate, with [18F]fluoride using tetraethylammonium bicarbonate in acetonitrile at 100∘C. The process was fully automated on a Trasis AllinOne synthesiser using an in-house designed cassette and sequence. With a relatively small precursor load of 4 mg, [18F]DPA-714 was obtained with consistently high radiochemical yields of 55-71% (n=6) and molar activities of 117-350 GBq/µmol at end of synthesis. With a single production batch, starting with 31-42 GBq of [18F]fluoride, between 13-20 GBq of the tracer can be produced, enabling multi-centre studies. Conclusion To the best of our knowledge, the process presented herein is the most efficient [18F]DPA-714 synthesis, with advantageous GMP compliance. The use of a Trasis AllinOne synthesiser increases reliability and allows rapid training of production staff.

scholarly journals Ferroptosis contributes to isoflurane-induced neurotoxicity and learning and memory impairment

2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Pengfei Liu ◽  
Jing Yuan ◽  
Yetong Feng ◽  
Xin Chen ◽  
Guangsuo Wang ◽  
...  
Keyword(s):  
Cell Death ◽  
Learning And Memory ◽  
Memory Impairment ◽  
Close Association ◽  
Dimethyl Fumarate ◽  
Dependent Manner ◽  
Transport Chain ◽  
The Relationship

AbstractFerroptosis is a novel type of programmed cell death, which is different from apoptosis and autophagic cell death. Recently, ferroptosis has been indicated to contribute to the in vitro neurotoxicity induced by isoflurane, which is one of the most common anesthetics in clinic. However, the in vivo position of ferroptosis in isoflurane-induced neurotoxicity as well as learning and memory impairment remains unclear. In this study, we mainly explored the relationship between ferroptosis and isoflurane-induced learning and memory, as well as the therapeutic methods in mouse model. Our results indicated that isoflurane induced the ferroptosis in a dose-dependent and time-dependent manner in hippocampus, the organ related with learning and memory ability. In addition, the activity of cytochrome c oxidase/Complex IV in mitochondrial electron transport chain (ETC) was increased by isoflurane, which might further contributed to cysteine deprivation-induced ferroptosis caused by isoflurane exposure. More importantly, isoflurane-induced ferroptosis could be rescued by both ferroptosis inhibitor (ferrostatin-1) and mitochondria activator (dimethyl fumarate), which also showed effective therapeutic action against isoflurane-induced learning and memory impairment. Taken together, our data indicate the close association among ferroptosis, mitochondria and isoflurane, and provide a novel insight into the therapy mode against isoflurane-induced learning and memory impairment.

scholarly journals METTL14 promotes tumorigenesis by regulating lncRNA OIP5-AS1/miR-98/ADAMTS8 signaling in papillary thyroid cancer

2021 ◽  
Vol 12 (6) ◽  
Author(s):  
Xiaoping Zhang ◽  
Dan Li ◽  
Chengyou Jia ◽  
Haidong Cai ◽  
Zhongwei Lv ◽  
...  
Keyword(s):  
Cell Proliferation ◽  
Thyroid Cancer ◽  
Papillary Thyroid Cancer ◽  
Xenograft Model ◽  
Luciferase Reporter ◽  
Papillary Thyroid ◽  
Qrt Pcr ◽  
The Relationship

Abstract Background Papillary thyroid cancer (PTC) is the most common type of cancer of the endocrine system. Long noncoding RNAs (lncRNAs) are emerging as a novel class of gene expression regulators associated with tumorigenesis. Through preexisting databases available for differentially expressed lncRNAs in PTC, we uncovered that lncRNA OIP5-AS1 was significantly upregulated in PTC tissues. However, the function and the underlying mechanism of OIP5-AS1 in PTC are poorly understood. Methods Expression of lncRNA OIP5-AS1 and miR-98 in PTC tissue and cells were measured by quantitative real-time PCR (qRT-PCR). And expression of METTL14 and ADAMTS8 in PTC tissue and cells were measured by qRT-PCR and western blot. The biological functions of METTL14, OIP5-AS1, and ADAMTS8 were examined using MTT, colony formation, transwell, and wound healing assays in PTC cells. The relationship between METTL14 and OIP5-AS1 were evaluated using RNA immunoprecipitation (RIP) and RNA pull down assay. And the relationship between miR-98 and ADAMTS8 were examined by luciferase reporter assay. For in vivo experiments, a xenograft model was used to investigate the effects of OIP5-AS1 and ADAMTS8 in PTC. Results Functional validation revealed that OIP5-AS1 overexpression promotes PTC cell proliferation, migration/invasion in vitro and in vivo, while OIP5-AS1 knockdown shows an opposite effect. Mechanistically, OIP5-AS1 acts as a target of miR-98, which activates ADAMTS8. OIP5-AS1 promotes PTC cell progression through miR-98/ADAMTS8 and EGFR, MEK/ERK pathways. Furthermore, RIP and RNA pull down assays identified OIP5-AS1 as the downstream target of METTL14. Overexpression of METTL14 suppresses PTC cell proliferation and migration/invasion through inhibiting OIP5-AS1 expression and regulating EGFR, MEK/ERK pathways. Conclusions Collectively, our findings demonstrate that OIP5-AS1 is a METTL14-regulated lncRNA that plays an important role in PTC progression and offers new insights into the regulatory mechanisms underlying PTC development.

scholarly journals Role of SHH in Patterning Human Pluripotent Cells towards Ventral Forebrain Fates

Cells ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 914
Author(s):  
Melanie V. Brady ◽  
Flora M. Vaccarino
Keyword(s):  
Stem Cell ◽  
Human Brain ◽  
Human Development ◽  
Disease Modeling ◽  
Model Systems ◽  
Advantages And Disadvantages ◽  
Technical Ability ◽  
Cellular Phenotypes

The complexities of human neurodevelopment have historically been challenging to decipher but continue to be of great interest in the contexts of healthy neurobiology and disease. The classic animal models and monolayer in vitro systems have limited the types of questions scientists can strive to answer in addition to the technical ability to answer them. However, the tridimensional human stem cell-derived organoid system provides the unique opportunity to model human development and mimic the diverse cellular composition of human organs. This strategy is adaptable and malleable, and these neural organoids possess the morphogenic sensitivity to be patterned in various ways to generate the different regions of the human brain. Furthermore, recapitulating human development provides a platform for disease modeling. One master regulator of human neurodevelopment in many regions of the human brain is sonic hedgehog (SHH), whose expression gradient and pathway activation are responsible for conferring ventral identity and shaping cellular phenotypes throughout the neural axis. This review first discusses the benefits, challenges, and limitations of using organoids for studying human neurodevelopment and disease, comparing advantages and disadvantages with other in vivo and in vitro model systems. Next, we explore the range of control that SHH exhibits on human neurodevelopment, and the application of SHH to various stem cell methodologies, including organoids, to expand our understanding of human development and disease. We outline how this strategy will eventually bring us much closer to uncovering the intricacies of human neurodevelopment and biology.

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