494 results match your criteria: "Crump Institute for Molecular Imaging[Affiliation]"

A digital phoswich detector using time-over-threshold for depth of interaction in PET.

Phys Med Biol

December 2020

Crump Institute for Molecular Imaging, David Geffen School of Medicine, University of California, Los Angeles, CA, United States of America.

We present the performance of a digital phoswich positron emission tomography (PET) detector, composed by layers of pixilated scintillator arrays, read out by solid state light detectors and an application specific integrated circuit (ASIC). We investigated the use of integrated charge from the scintillation pulses along with time-over-threshold (ToT) to determine the layer of interaction (DOI) in the scintillator. Simulations were performed to assess the effectiveness of the ToT measurements for separating the scintillator events and identifying cross-layer-crystal-scatter (CLCS) events.

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Cervical-Vaginal Microbiome and Associated Cytokine Profiles in a Prospective Study of HPV 16 Acquisition, Persistence, and Clearance.

Front Cell Infect Microbiol

June 2021

Department of Molecular and Medical Pharmacology, David Geffen School of Medicine, Crump Institute for Molecular Imaging, University of California, Los Angeles, Los Angeles, CA, United States.

Persistent human papillomavirus (HPV) infections is necessary for the development of cervical cancers. Consequently, understanding the biologic mechanisms resulting in clearance is key in cancer prevention. Similar to other mucosal sites, it is expected that the local microbiome plays a significant role in shaping the immune response responsible for HPV clearance.

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Supramolecular nanosubstrate-mediated delivery system enables CRISPR-Cas9 knockin of hemoglobin beta gene for hemoglobinopathies.

Sci Adv

October 2020

Department of Molecular and Medical Pharmacology, Crump Institute for Molecular Imaging (CIMI), California NanoSystems Institute (CNSI), University of California, Los Angeles, Los Angeles, CA 90095, USA.

Leveraging the endogenous homology-directed repair (HDR) pathway, the CRISPR-Cas9 gene-editing system can be applied to knock in a therapeutic gene at a designated site in the genome, offering a general therapeutic solution for treating genetic diseases such as hemoglobinopathies. Here, a combined supramolecular nanoparticle (SMNP)/supramolecular nanosubstrate-mediated delivery (SNSMD) strategy is used to facilitate CRISPR-Cas9 knockin of the hemoglobin beta (HBB) gene into the adeno-associated virus integration site 1 (AAVS1) safe-harbor site of an engineered K562 3.21 cell line harboring the sickle cell disease mutation.

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Development of a Potent Brain-Penetrant EGFR Tyrosine Kinase Inhibitor against Malignant Brain Tumors.

ACS Med Chem Lett

October 2020

Departments of Molecular and Medical Pharmacology, Chemistry and Biochemistry, Jane and Terry Semel Institute for Neuroscience and Human Behavior and Department of Psychiatry and Biobehavioral Sciences, Neurology, and Crump Institute for Molecular Imaging, University of California, Los Angeles, California 90095, United States.

The epidermal growth factor receptor (EGFR) is genetically altered in nearly 60% of glioblastoma tumors; however, tyrosine kinase inhibitors (TKIs) against EGFR have failed to show efficacy for patients with these lethal brain tumors. This failure is attributed to the inability of clinically tested EGFR TKIs to cross the blood-brain barrier (BBB) and achieve adequate pharmacological levels to inhibit various oncogenic forms of EGFR that drive glioblastoma. Through SAR analysis, we developed compound (JCN037) from an anilinoquinazoline scaffold by ring fusion of the 6,7-dialkoxy groups to reduce the number of rotatable bonds and polar surface area and by introduction of an -fluorine and -bromine on the aniline ring for improved potency and BBB penetration.

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Hepatocellular carcinoma (HCC) is a leading cause of mortality. Checkpoint inhibitors of programmed cell death protein-1 (PD-1) and programmed death-ligand 1 (PD-L1) have shown great efficacy, but lack biomarkers that predict response. Circulating tumor cells (CTCs) have promise as a liquid-biopsy biomarker; however, data on HCC CTCs expressing PD-L1 have not been reported.

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Translocation of Viable Gut Microbiota to Mesenteric Adipose Drives Formation of Creeping Fat in Humans.

Cell

October 2020

F. Widjaja Foundation Inflammatory Bowel and Immunobiology Research Institute, Cedars-Sinai Medical Center, Los Angeles, CA 90048, USA; Department of Biomedical Sciences, Cedars-Sinai Medical Center, Los Angeles, CA 90048, USA. Electronic address:

A mysterious feature of Crohn's disease (CD) is the extra-intestinal manifestation of "creeping fat" (CrF), defined as expansion of mesenteric adipose tissue around the inflamed and fibrotic intestine. In the current study, we explore whether microbial translocation in CD serves as a central cue for CrF development. We discovered a subset of mucosal-associated gut bacteria that consistently translocated and remained viable in CrF in CD ileal surgical resections, and identified Clostridium innocuum as a signature of this consortium with strain variation between mucosal and adipose isolates, suggesting preference for lipid-rich environments.

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Purification of HCC-specific extracellular vesicles on nanosubstrates for early HCC detection by digital scoring.

Nat Commun

September 2020

California NanoSystems Institute, Crump Institute for Molecular Imaging, Department of Molecular and Medical Pharmacology, University of California, Los Angeles, CA, 90095, USA.

We report a covalent chemistry-based hepatocellular carcinoma (HCC)-specific extracellular vesicle (EV) purification system for early detection of HCC by performing digital scoring on the purified EVs. Earlier detection of HCC creates more opportunities for curative therapeutic interventions. EVs are present in circulation at relatively early stages of disease, providing potential opportunities for HCC early detection.

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Disrupted energy metabolism drives cell dysfunction and disease, but approaches to increase or preserve ATP are lacking. To generate a comprehensive metabolic map of genes and pathways that regulate cellular ATP-the ATPome-we conducted a genome-wide CRISPR interference/activation screen integrated with an ATP biosensor. We show that ATP level is modulated by distinct mechanisms that promote energy production or inhibit consumption.

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Microbes and their metabolic products influence early-life immune and microbiome development, yet remain understudied during pregnancy. Vaginal microbial communities are typically dominated by one or a few well-adapted microbes which are able to survive in a narrow pH range and are adapted to live on host-derived carbon sources, likely sourced from glycogen and mucin present in the vaginal environment. We characterized the cervicovaginal microbiomes of 16 healthy women throughout the three trimesters of pregnancy.

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Thermodynamic energetics underlying genomic instability and whole-genome doubling in cancer.

Proc Natl Acad Sci U S A

August 2020

Fritz Haber Center for Molecular Dynamics, Institute of Chemistry, The Hebrew University of Jerusalem, 91904 Jerusalem, Israel;

Genomic instability contributes to tumorigenesis through the amplification and deletion of cancer driver genes. DNA copy number (CN) profiling of ensembles of tumors allows a thermodynamic analysis of the profile for each tumor. The free energy of the distribution of CNs is found to be a monotonically increasing function of the average chromosomal ploidy.

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Evaluation of [I]I- and [Lu]Lu-DTPA-A11 Minibody for Radioimmunotherapy in a Preclinical Model of PSCA-Expressing Prostate Cancer.

Mol Imaging Biol

October 2020

Department of Molecular and Medical Pharmacology, Crump Institute for Molecular Imaging, David Geffen School of Medicine, UC Los Angeles, Los Angeles, CA, USA.

Purpose: Radioimmunotherapy uses tumor-specific antibodies to deliver therapeutic radionuclides, but hematological toxicity due to the long serum half-life of intact antibodies remains a challenge. We evaluated a smaller antibody fragment, the minibody, with faster kinetics and a potentially improved therapeutic index.

Procedures: The anti-prostate stem cell antigen (PSCA) minibody (A11 Mb) was radiolabeled with iodine-124 ([I]I-A11 Mb) or conjugated with deferoxamine (DFO) and labeled with zirconium-89 ([Zr]Zr-DFO-A11 Mb) for surrogate immunoPET to profile pharmacokinetics in a human prostate cancer xenograft model.

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Cutibacterium acnes is capable of inducing inflammation in acne and can lead to a chronic prostatic infection. The diverse pathogenicity among different strains of C. acnes has been presented, but simple appropriate animal models for the evaluation of this bacterium are lacking.

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Determining the status of epidermal growth factor receptor (EGFR) T790M mutation is crucial for guiding further treatment intervention in advanced non-small cell lung cancer (NSCLC) patients who develop acquired resistance to initial EGFR tyrosine kinase inhibitor (TKI) treatment. Circulating tumor cells (CTCs) which contain plentiful copies of well-preserved RNA offer an ideal source for noninvasive detection of T790M mutation in NSCLC. We developed a CTC-based digital assay which synergistically integrates NanoVelcro Chips for enriching NSCLC CTCs and reverse-transcription droplet digital PCR (RT-ddPCR) for quantifying T790M transcripts in the enriched CTCs.

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The homology-independent targeted integration (HITI) strategy enables effective CRISPR/Cas9-mediated knockin of therapeutic genes in nondividing cells in vivo, promising general therapeutic solutions for treating genetic diseases like X-linked juvenile retinoschisis. Herein, supramolecular nanoparticle (SMNP) vectors are used for codelivery of two DNA plasmids-CRISPR-Cas9 genome-editing system and a therapeutic gene, Retinoschisin 1 (RS1)-enabling clustered regularly interspaced short palindromic repeats (CRISPR)-associated protein 9 (CRISPR/Cas9) knockin of the RS1 gene with HITI. Through small-scale combinatorial screenings, two SMNP vectors, with Cas9 and single guide RNA (sgRNA)-plasmid in one and Donor-RS1 and green fluorescent protein (GFP)-plasmid in the other, with optimal delivery performances are identified.

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MG-MLST: Characterizing the Microbiome at the Strain Level in Metagenomic Data.

Microorganisms

May 2020

Department of Molecular and Medical Pharmacology, Crump Institute for Molecular Imaging, University of California, Los Angeles, CA 90095, USA.

The microbiome plays an important role in human physiology. The composition of the human microbiome has been described at the phylum, class, genus, and species levels, however, it is largely unknown at the strain level. The importance of strain-level differences in microbial communities has been increasingly recognized in understanding disease associations.

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Acute radiation exposure of the thorax can lead to late serious, and even life-threatening, pulmonary and cardiac damage. Sporadic in nature, late complications tend to be difficult to predict, which prompted this investigation into identifying non-invasive, tissue-specific biomarkers for the early detection of late radiation injury. Levels of circulating microRNA (miRNA) were measured in C3H and C57Bl/6 mice after whole thorax irradiation at doses yielding approximately 70% mortality in 120 or 180 days, respectively (LD70/120 or 180).

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Author Correction: The balance of metagenomic elements shapes the skin microbiome in acne and health.

Sci Rep

April 2020

Department of Molecular and Medical Pharmacology, Crump Institute for Molecular Imaging, David Geffen School of Medicine, UCLA, Los Angeles, California, USA.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

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[This corrects the article DOI: 10.18632/oncotarget.5358.

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Comparison of the Efficacy and Sensitivity of Alternative PET Reporter Gene/PET Reporter Probe Systems That Minimize Biological Variables.

Methods Mol Biol

February 2021

Department of Molecular and Medical Pharmacology, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA, USA.

Positron emission tomography (PET) reporter genes (PRGs), when coupled with positron-emitting PET reporter probes (PRPs), are useful for tracking specific cell populations in cell-based therapies, in transgenic animal models, and in xenograft tumor progression experiments. The activities of incorporated PRGs in targeted cells can be monitored noninvasively by PET imaging in preclinical in vivo studies and clinical applications following systemic administration of the appropriate PRG. Here we describe a method that minimizes both design and variability of vector delivery vehicles for alternative PRGs and biological variability of the in vivo target when comparing the efficacy, sensitivity, and specificity of alternative PRG/PRP combinations for in vivo PRG imaging.

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Microfluidics offers numerous advantages for the synthesis of short-lived radiolabeled imaging tracers: performing F-radiosyntheses in microliter-scale droplets has exhibited high efficiency, speed, and molar activity as well as low reagent consumption. However, most reports have been at the preclinical scale. In this study we integrate a [F]fluoride concentrator and a microdroplet synthesizer to explore the possibility of synthesizing patient doses and multi-patient batches of clinically-acceptable tracers.

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Modeling Mixed Vascular and Alzheimer's Dementia Using Focal Subcortical Ischemic Stroke in Human ApoE4-TR:5XFAD Transgenic Mice.

Transl Stroke Res

October 2020

Department of Neurology, David Geffen School of Medicine, University of California Los Angeles, 635 Charles E. Young Dr. South, Neuroscience Research Building, Rm 415, Los Angeles, CA, 90095, USA.

Subcortical white matter ischemic lesions are increasingly recognized to have pathologic overlap in individuals with Alzheimer's disease (AD). The interaction of white matter ischemic lesions with amyloid pathology seen in AD is poorly characterized. We designed a novel mouse model of subcortical white matter ischemic stroke and AD that can inform our understanding of the cellular and molecular mechanisms of mixed vascular and AD dementia.

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Hepatocellular carcinoma (HCC) is among the leading causes of worldwide cancer-related morbidity and mortality. Poor prognosis of HCC is attributed primarily to tumor presentation at an advanced stage when there is no effective treatment to achieve the long term survival of patients. Currently available tests such as alpha-fetoprotein have limited accuracy as a diagnostic or prognostic biomarker for HCC.

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From an efficiency standpoint, microdroplet reactors enable significant improvements in the preparation of radiopharmaceuticals due to the vastly reduced reaction volume. To demonstrate these advantages, we adapt the conventional (macroscale) synthesis of the clinically-important positron-emission tomography tracer [F]FDOPA, following the nucleophilic diaryliodonium salt approach, to a newly-developed ultra-compact microdroplet reaction platform. In this first microfluidic implementation of [F]FDOPA synthesis, optimized via a high-throughput multi-reaction platform, the radiochemical yield (non-decay-corrected) was found to be comparable to macroscale reports, but the synthesis consumed significantly less precursor and organic solvents, and the synthesis process was much faster.

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Integration of High-Resolution Radiation Detector for Hybrid Microchip Electrophoresis.

Anal Chem

February 2020

Crump Institute for Molecular Imaging and Department of Molecular and Medical Pharmacology, David Geffen School of Medicine , University of California Los Angeles, Los Angeles , California 90095 , United States.

For decades, there has been immense progress in miniaturizing analytical methods based on electrophoresis to improve sensitivity and to reduce sample volumes, separation times, and/or equipment cost and space requirements, in applications ranging from analysis of biological samples to environmental analysis to forensics. In the field of radiochemistry, where radiation-shielded laboratory space is limited, there has been great interest in harnessing the compactness, high efficiency, and speed of microfluidics to synthesize short-lived radiolabeled compounds. We recently proposed that analysis of these compounds could also benefit from miniaturization and have been investigating capillary electrophoresis (CE) and hybrid microchip electrophoresis (hybrid-MCE) as alternatives to the typically used high-performance liquid chromatography (HPLC).

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Porphyrin Production and Regulation in Cutaneous Propionibacteria.

mSphere

January 2020

Department of Molecular and Medical Pharmacology, Crump Institute for Molecular Imaging, David Geffen School of Medicine, UCLA, Los Angeles, California, USA

Porphyrins are intermediate metabolites in the biosynthesis of vital molecules, including heme, cobalamin, and chlorophyll. Bacterial porphyrins are known to be proinflammatory, with high levels linked to inflammatory skin diseases. species are dominant skin commensals and play essential roles in defending against pathogens and in triggering an inflammatory response.

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