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Metabolism: Clinical and Experimental Jan 2021Glycolysis controls mTORC1 signaling and protein synthesis. In skeletal muscle, glucose metabolism increases with both exercise/contraction intensity and volume, and...
BACKGROUND
Glycolysis controls mTORC1 signaling and protein synthesis. In skeletal muscle, glucose metabolism increases with both exercise/contraction intensity and volume, and therefore, high-intensity muscle contraction (HiMC) such as resistance exercise facilitates glycolysis including glucose uptake and glycogen breakdown. However, it is unknown whether glycolysis regulates HiMC-induced mTORC1 activation and increase in protein synthesis.
METHODS
To determine whether glycolysis regulates basal and HiMC-induced mTORC1 signaling and protein synthesis, we employed 2-deoxyglucose (2-DG) to inhibit glycolysis and isometrically contracted the gastrocnemius muscle of Sprague Dawley rats using percutaneous electrical stimulation.
RESULTS
Inhibition of glycolysis by 2-DG inhibited basal phosphorylation of p70S6K and 4E-BP1 (downstream targets of mTORC1) and protein synthesis (all P < 0.05) independent of AMPK phosphorylation. AMPK phosphorylation was comparably increased after HiMC at 0 h post HiMC and returned to basal levels 6 h post HiMC in both vehicle- and 2-DG-treated groups. Glycolysis inhibition attenuated muscle contraction-induced phosphorylation of 4E-BP1 at 6 h post HiMC (P < 0.05) but not p70S6K phosphorylation and protein synthesis.
CONCLUSION
Although glycolysis is involved in basal but not HiMC-induced muscle protein synthesis, it regulates both basal and HiMC-induced mTORC1 signaling, and may play key roles in skeletal muscle adaptation to HiMC.
Topics: Adenylate Kinase; Animals; Deoxyglucose; Glycolysis; Intracellular Signaling Peptides and Proteins; Male; Muscle Contraction; Muscle, Skeletal; Phosphorylation; Protein Biosynthesis; Rats; Rats, Sprague-Dawley; Ribosomal Protein S6 Kinases, 70-kDa; Signal Transduction; TOR Serine-Threonine Kinases
PubMed: 33161019
DOI: 10.1016/j.metabol.2020.154419 -
Nuclear Medicine Communications Nov 2023In this study, the potential advantage of FAPI over 18 F-labelled deoxyglucose ( 18 F-FDG) in evaluation of the initial staging colorectal cancer (CRC) was investigated.
OBJECTIVE
In this study, the potential advantage of FAPI over 18 F-labelled deoxyglucose ( 18 F-FDG) in evaluation of the initial staging colorectal cancer (CRC) was investigated.
MATERIALS AND METHODS
Thirty-two patients with histopathologically confirmed primary CRC were included in our study. They all underwent both 18 F-FDG and FAPI PET/CT. Lesion detectability and tracer uptakes, mainly quantified by maximum standardized uptake value (SUVmax) and target-to-background ratio (TBR), were compared for paired lesions between both modalities using the Wilcoxon signed-rank test and paired t-test.
RESULTS
Thirty-five CRC lesions in 32 patients were diagnosed. The sensitivity of FAPI PET/CT in diagnosis of the CRC lesions was 100% while 93.8% of 18 F-FDG PET/CT. FAPI and 18 F-FDG had a similar uptake in CRC lesion (mean SUVmax: 14.3 ± 8.6 vs. 15.4 ± 9.8, P = 0.604), but lesions contained mucus and/or signet-ring cell carcinoma seemed to have a trend of higher FAPI uptake although there was no statistical difference (mean SUVmax: 12.7 ± 5.6 vs. 8.5 ± 4.1, P = 0.152) and higher TBR (13.4 ± 6.2 vs. 4.9 ± 2.2, P = 0.004) than those of 18 F-FDG. For regional lymph node metastases, both FAPI and FDG PET/CTs showed high sensitivity (7/8 vs. 7/8), specificity (7/8 vs. 6/8) and accuracy (14/16 vs. 13/16) (all P > 0.05). For distant metastasis, FAPI PET/CT depicted more positive lesions in distant lymph node (46 vs. 26), liver (13 vs. 7) and peritoneum (107 vs. 45) than 18 F-FDG PET/CT. FAPI PET/CT also had a higher peritoneal cancer index score (median 11 vs 4; P < 0.001) than 18 F-FDG PET/CT in evaluation of peritoneal metastases.
CONCLUSION
FAPI PET/CT showed high sensitivity in detection of primary CRC and superiority to 18 F-FDG PET/CT in detection of metastases to distant lymph node, liver and peritoneum.
Topics: Humans; Positron Emission Tomography Computed Tomography; Fluorodeoxyglucose F18; Positron-Emission Tomography; Colorectal Neoplasms; Fibroblasts; Gallium Radioisotopes; Quinolines
PubMed: 37661771
DOI: 10.1097/MNM.0000000000001751 -
Sensors (Basel, Switzerland) Jun 2022The aim of this study is to evaluate the performance of the Radialis organ-targeted positron emission tomography (PET) Camera with standardized tests and through...
The aim of this study is to evaluate the performance of the Radialis organ-targeted positron emission tomography (PET) Camera with standardized tests and through assessment of clinical-imaging results. Sensitivity, count-rate performance, and spatial resolution were evaluated according to the National Electrical Manufacturers Association (NEMA) NU-4 standards, with necessary modifications to accommodate the planar detector design. The detectability of small objects was shown with micro hotspot phantom images. The clinical performance of the camera was also demonstrated through breast cancer images acquired with varying injected doses of 2-[fluorine-18]-fluoro-2-deoxy-D-glucose (F-FDG) and qualitatively compared with sample digital full-field mammography, magnetic resonance imaging (MRI), and whole-body (WB) PET images. Micro hotspot phantom sources were visualized down to 1.35 mm-diameter rods. Spatial resolution was calculated to be 2.3 ± 0.1 mm for the in-plane resolution and 6.8 ± 0.1 mm for the cross-plane resolution using maximum likelihood expectation maximization (MLEM) reconstruction. The system peak noise equivalent count rate was 17.8 kcps at a F-FDG concentration of 10.5 kBq/mL. System scatter fraction was 24%. The overall efficiency at the peak noise equivalent count rate was 5400 cps/MBq. The maximum axial sensitivity achieved was 3.5%, with an average system sensitivity of 2.4%. Selected results from clinical trials demonstrate capability of imaging lesions at the chest wall and identifying false-negative X-ray findings and false-positive MRI findings, even at up to a 10-fold dose reduction in comparison with standard F-FDG doses (i.e., at 37 MBq or 1 mCi). The evaluation of the organ-targeted Radialis PET Camera indicates that it is a promising technology for high-image-quality, low-dose PET imaging. High-efficiency radiotracer detection also opens an opportunity to reduce administered doses of radiopharmaceuticals and, therefore, patient exposure to radiation.
Topics: Fluorodeoxyglucose F18; Humans; Phantoms, Imaging; Positron-Emission Tomography; Reference Standards
PubMed: 35808181
DOI: 10.3390/s22134678 -
Nuclear Medicine Communications Jun 2021The most prevalent primary malignancy of the liver is hepatocellular carcinoma (HCC); its poor prognosis is mainly related to intrahepatic recurrence and extrahepatic...
The most prevalent primary malignancy of the liver is hepatocellular carcinoma (HCC); its poor prognosis is mainly related to intrahepatic recurrence and extrahepatic metastases. However, survival from HCC has improved due to better control of the primary tumor, the development of newer treatment modalities, including liver transplant, together with advances in imaging techniques. Therefore, the significance of patient management as corresponds with distant metastases has increased; since the proper evaluation and detection of extrahepatic metastases is crucial to optimize potential therapy for patients. Conventional imaging like CT, MRI play crucial rule in patient's diagnosis and qualifying for a certain type of therapy. More recently, a molecular imaging tool with radiolabeled deoxyglucose and fluorocholine has proved its promising value as a complementary tool to conventional studies. In this review, the frequent sites of metastases and HCC spread are discussed as well as the imaging findings as seen by both conventional imaging techniques and by molecular imaging tools, namely 18F-Choline PET/CT, and FDG PET. The implications of guiding treatment planning have also been discussed.
Topics: Aged; Carcinoma, Hepatocellular; Fluorodeoxyglucose F18; Humans; Liver Neoplasms; Middle Aged; Positron Emission Tomography Computed Tomography
PubMed: 33625188
DOI: 10.1097/MNM.0000000000001380 -
Seminars in Nuclear Medicine Nov 2020Radiomics describes the extraction of multiple features from medical images, including molecular imaging modalities, that with bioinformatic approaches, provide... (Review)
Review
Radiomics describes the extraction of multiple features from medical images, including molecular imaging modalities, that with bioinformatic approaches, provide additional clinically relevant information that may be invisible to the human eye. This information may complement standard radiological interpretation with data that may better characterize a disease or that may provide predictive or prognostic information. Progressing from predefined image features, often describing heterogeneity of voxel intensities within a volume of interest, there is increasing use of machine learning to classify disease characteristics and deep learning methods based on artificial neural networks that can learn features without a priori definition and without the need for preprocessing of images. There have been advances in standardization and harmonization of methods to a level that should support multicenter studies. However, in this relatively early phase of research in the field, there are limited aspects that have been adopted into routine practice. Most of the reports in the molecular imaging field describe radiomic approaches in cancer using F-fluorodeoxyglucose positron emission tomography (F-FDG-PET). In this review, we will describe radiomics in molecular imaging and summarize the pertinent literature in lung cancer where reports are most prevalent and mature.
Topics: Fluorodeoxyglucose F18; Humans; Image Processing, Computer-Assisted; Positron-Emission Tomography; Precision Medicine
PubMed: 33059822
DOI: 10.1053/j.semnuclmed.2020.05.002 -
Journal of Nuclear Medicine Technology Mar 2021Our objective was to investigate the differences in texture features between step-and-shoot (SS) and continuous-bed-motion (CBM) imaging in phantom and clinical studies....
Our objective was to investigate the differences in texture features between step-and-shoot (SS) and continuous-bed-motion (CBM) imaging in phantom and clinical studies. A National Electrical Manufacturers Association body phantom was filled with F-FDG solution at a sphere-to-background ratio of 4:1. SS and CBM were performed using the same acquisition duration, and the data were reconstructed using 3-dimensional ordered-subset expectation maximization with time-of-flight algorithms. Texture features were extracted using the software LIFEx. A volume of interest was delineated on the 22-, 28-, and 37-mm spheres with a threshold of 42% of the maximum SUV. The voxel intensities were discretized using 2 resampling methods, namely a fixed bin size and a fixed bin number discretization. The discrete resampling values were set to 64 and 128. In total, 31 texture features were calculated with gray-level cooccurrence matrix (GLCM), gray-level run length matrix, neighborhood gray-level different matrix, and gray-level zone length matrix. The texture features of the SS and CBM images were compared for all settings using the paired test and the coefficient of variation. In a clinical study, 27 lesions from 20 patients were examined using the same acquisition and image processing as were used during the phantom study. The percentage difference (%Diff) and correlation between the texture features from SS and CBM images were calculated to evaluate agreement between the 2 scanning techniques. In the phantom study, the 11 features exhibited no significant difference between SS and CBM images, and the coefficient of variation was no more than 10%, depending on resampling conditions, whereas entropy and dissimilarity from GLCM fulfilled the criteria for all settings. In the clinical study, the entropy and dissimilarity from GLCM exhibited a low %Diff and excellent correlation in all resampling conditions. The %Diff of entropy was lower than that of dissimilarity. Differences between the texture features of SS and CBM images varied depending on the type of feature. Because entropy for GLCM exhibits minimal differences between SS and CBM images irrespective of resampling conditions, entropy may be the optimal feature to reduce the differences between the 2 scanning techniques.
Topics: Algorithms; Fluorodeoxyglucose F18; Humans; Image Processing, Computer-Assisted; Motion; Phantoms, Imaging
PubMed: 33020230
DOI: 10.2967/jnmt.120.246157 -
PET Clinics Apr 20212-[18F]-fluoro-2-deoxyglucose (FDG) is the most commonly used radiotracer and provides valuable information about glucose metabolism. With the advent of newer... (Review)
Review
2-[18F]-fluoro-2-deoxyglucose (FDG) is the most commonly used radiotracer and provides valuable information about glucose metabolism. With the advent of newer receptor-based tracers in the management of hormonally active malignancies, the focus has been shifted from FDG. These tracers might be more specific than FDG because they target specific hormone receptors. But because FDG is widely available, this review discusses what information still can be harnessed from this workhorse of molecular imaging. The personalized implementation of FDG imaging in undifferentiated malignancies will help in characterization of tumor and may aid in patient management.
Topics: Fluorodeoxyglucose F18; Glucose; Humans; Neoplasms
PubMed: 33648663
DOI: 10.1016/j.cpet.2020.12.007 -
Acta Neurologica Scandinavica Dec 2022F-fluoro-deoxyglucose position emission tomography ( F-FDG-PET) has been proven as a sensitive and reliable tool for diagnosis of autoimmune encephalitis (AE). More... (Review)
Review
F-fluoro-deoxyglucose position emission tomography ( F-FDG-PET) has been proven as a sensitive and reliable tool for diagnosis of autoimmune encephalitis (AE). More attention was paid to this kind of imaging because of the shortage of MRI, EEG, and CSF findings. FDG-PET has been assessed in a few small studies and case reports showing apparent abnormalities in cases where MRI does not. Here, we summarized the patterns (specific or not) in AE with different antibodies detected and the clinical outlook for the wide application of FDG-PET considering some limitations. Specific patterns based on antibody subtypes and clinical symptoms were critical for identifying suspicious AE, the most common of which was the anteroposterior gradient in anti- N -methyl- d -aspartate receptor (NMDAR) encephalitis and the medial temporal lobe hypermetabolism in limbic encephalitis. And the dynamic changes of metabolic presentations in different phases provided us the potential to inspect the evolution of AE and predict the functional outcomes. Except for the visual assessment, quantitative analysis was recently reported in some voxel-based studies of regions of interest, which suggested some clues of the future evaluation of metabolic abnormalities. Large prospective studies need to be conducted controlling the time from symptom onset to examination with the same standard of FDG-PET scanning.
Topics: Humans; Fluorodeoxyglucose F18; Prospective Studies; Positron-Emission Tomography; Anti-N-Methyl-D-Aspartate Receptor Encephalitis
PubMed: 36259555
DOI: 10.1111/ane.13717 -
Reviews in Endocrine & Metabolic... Feb 2024In the last years growing evidences on the role of radiomics and machine learning (ML) applied to different nuclear medicine imaging modalities for the assessment of... (Review)
Review
BACKGROUND
In the last years growing evidences on the role of radiomics and machine learning (ML) applied to different nuclear medicine imaging modalities for the assessment of thyroid diseases are starting to emerge. The aim of this systematic review was therefore to analyze the diagnostic performances of these technologies in this setting.
METHODS
A wide literature search of the PubMed/MEDLINE, Scopus and Web of Science databases was made in order to find relevant published articles about the role of radiomics or ML on nuclear medicine imaging for the evaluation of different thyroid diseases.
RESULTS
Seventeen studies were included in the systematic review. Radiomics and ML were applied for assessment of thyroid incidentalomas at F-FDG PET, evaluation of cytologically indeterminate thyroid nodules, assessment of thyroid cancer and classification of thyroid diseases using nuclear medicine techniques.
CONCLUSION
Despite some intrinsic limitations of radiomics and ML may have affect the results of this review, these technologies seem to have a promising role in the assessment of thyroid diseases. Validation of preliminary findings in multicentric studies is needed to translate radiomics and ML approaches in the clinical setting.
Topics: Humans; Fluorodeoxyglucose F18; Machine Learning; Nuclear Medicine; Radiomics; Thyroid Neoplasms; Thyroid Nodule; Thyroid Diseases
PubMed: 37434097
DOI: 10.1007/s11154-023-09822-4 -
International Journal of Molecular... Jan 2022Excessive glucose metabolism and disruptions in Wnt signaling are important molecular changes present in oral cancer cells. The aim of this study was to evaluate the...
Excessive glucose metabolism and disruptions in Wnt signaling are important molecular changes present in oral cancer cells. The aim of this study was to evaluate the effects of the combinatorial use of glycolysis and Wnt signaling inhibitors on viability, cytotoxicity, apoptosis induction, cell cycle distribution and the glycolytic activity of tongue carcinoma cells. CAL 27, SCC-25 and BICR 22 tongue cancer cell lines were used. Cells were treated with inhibitors of glycolysis (2-deoxyglucose and lonidamine) and of Wnt signaling (PRI-724 and IWP-O1). The effects of the compounds on cell viability and cytotoxicity were evaluated with MTS and CellTox Green tests, respectively. Apoptosis was evaluated by MitoPotential Dye staining and cell cycle distribution by staining with propidium iodide, followed by flow cytometric cell analysis. Glucose and lactate concentrations in a culture medium were evaluated luminometrically. Combinations of 2-deoxyglucose and lonidamine with Wnt pathway inhibitors were similarly effective in the impairment of oral cancer cells' survival. However, the inhibition of the canonical Wnt pathway by PRI-724 was more beneficial, based on the glycolytic activity of the cells. The results point to the therapeutic potential of the combination of low concentrations of glycolytic modulators with Wnt pathway inhibitors in oral cancer cells.
Topics: Apoptosis; Bridged Bicyclo Compounds, Heterocyclic; Cell Cycle; Cell Line, Tumor; Cell Survival; Deoxyglucose; Glucose; Glycolysis; Head and Neck Neoplasms; Humans; Indazoles; Pyrimidinones; Tongue; Tongue Neoplasms; Wnt Signaling Pathway
PubMed: 35163171
DOI: 10.3390/ijms23031248