175 research outputs found

    A Time-Space Analysis of Urban Activities with Focus on the Relationship between ICT and Activity-Travel

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    Information and communications technology (ICT) has evolved substantially and impacted urban residents’ everyday life quite substantially in the past decade. The rapid spread of mobile telecommunications technologies has produced significant changes in relationships among communications, marketing and distribution, and transportation. As mobile technologies diminish time-space constraints that have governed telecommunication, they are prompting the emergence of new life styles with unprecedented ways in which urban space is consumed. The focus of this study is on how mobile telecommunication technologies have influenced daily activity and travel behaviors of urban residents. Temporal and spatial characteristics of their activity-travel patterns are empirically analyzed using activity diary data sets collected by the authors in the Kofu area of Japan. The survey is designed with the intent of capturing both patterns of movements in the urban area and patterns of activities that induced the movements. Questions regarding telecommunications activities are introduced into the activity-travel diary that had been developed by the authors to facilitate the acquisition of information on the occurrence and contents of telecommunications activities. The analytical framework of this study is formed by integrating urban residents’ time-space paths and virtual links representing telecommunications activities. Time-space paths are formed in a physical urban space while satisfying temporal and spatial constraints imposed by Hägerstrand’s prism. Conventional means of inter-individual communication (meeting, stationary telephones, mailed letters and telegrams) are all subject to certain constraints in the time-space domain. On the other hand, telecommunications activities by mobile technologies are not subjected to many of the constraints and can influence travel decisions more spontaneously than do conventional means of communication. Several hypotheses concerning ICT and activity patterns are postulated and empirically examined with the results of the diary surveys. Examples of the hypotheses are as follows. As the use of mobile telecommunications technologies increases, 1) the activity frequency tends to increase, 2) the spatial distribution of activities tends to spread out, that is, the action space tends to expand spatially, and 3) patterns of trip chaining tend to change themselves, with more stops incorporated into a home-based trip chain (i.e., a sequence of trips starting from and ending at home, through which a set of activity locations are visited). It is also hypothesized that 4) the way mobile technologies influence the individual’s activity-travel patterns varies by his personal characteristics, especially life cycle stage and life style. The Survey of Communication, Activity and Travel, denoted by “SCAT,” was conducted twice to form the database of this study. The first survey involved about 150 university students and data on weekly activity patterns and mobile telecommunication incidents were collected. The second survey addressed about 150 households (322 individuals) and activity diaries on two consecutive days and mobile telecommunication information were obtained. The first SCAT data are used to examine basic properties of ICT–activity-travel relationships of “heavy mobile-informed travelers” because students are certainly standing on the forefront of ICT use. On the other hand, the second SCAT data are used to analyze characteristics of joint activity engagement by household members as a result of ICT use among household members. Then, using both of the SCAT data sets, the hypotheses are examined and statistical evidence is presented. Finally, implications of the findings are summarized and directions are suggested for future research on ICT, activity and travel.

    Selective neuronal damage and Wisconsin Card Sorting Test performance in atherosclerotic occlusive disease of the major cerebral artery

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    In atherosclerotic internal carotid artery (ICA) or middle cerebral artery (MCA) disease, selective neuronal damage can be detected as a decrease in central benzodiazepine receptors (BZRs) in the normal-appearing cerebral cortex. This study aimed to determine whether a decrease in the BZRs in the non-infarcted cerebral cortex is associated with poor performance on the Wisconsin Card Sorting Test (WCST), which assesses executive functions

    An artificial amino acid, 4-iodo-L-meta-tyrosine: Biodistribution and excretion via kidney

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    金沢大学大学院医学系研究科We evaluated the use of radiolabeled 4-iodo-L-meta-tyrosine as an amino acid transport marker. The pharmacologic features of this compound, particularly the biodistribution and excretion, were examined by conducting in vivo and in vitro studies using 4-125I-iodo-L-meta-tyrosine (4- 125I-mTyr). Results obtained for L-14C-Tyr and 3- 125I-iodo-α-methyl-L-tyrosine (125I-IMT) were used for comparison. Methods: In vivo biodistribution studies of 4- 125I-mTyr were performed in male ddY mice. Urinary excretion of 4-125I-mTyr and 125I-IMT with administration of probenecid was studied. Local distribution of 4-125I-mTyr and 125I-IMT in kidney was visualized by autoradiography. We performed metabolite analysis of 4-125I-mTyr in mice. For in vitro studies, reabsorption mechanisms of 4-125I-mTyr were compared with those of 125I-IMT and the parent L-14C-Tyr using superconfluent monolayers of the porcine kidney epithelial cell line LLC-PK1 in medium containing inhibitor (L-Tyr, D-Tyr, and 2,4-dinitrophenol), in Na +-free medium, and at 4°C. Results: 4-125I-mTyr demonstrated high accumulation in the pancreas and kidney and comparable brain uptake to that of 125I-IMT. Blood clearance of 4-125I-mTyr was faster than that of 125I-IMT. Three hours after administration, >70% of 4-125I-mTyr was excreted via the urine, whereas 98.1% of the total present in kidney and >96.3% in urine. Protein incorporation was not observed. Uptake of 4-125I-mTyr into LLC-PK1 cell monolayers was remarkably reduced by 5 mmol/L L-Tyr (4.6%) and incubation at 4°C (15.6%) but was reduced by 5 mmol/L D-Tyr (50.0%). L-14C-Tyr and 125I-IMT showed similar results; however, uptake of 125I-IMT was enhanced by 0.1 mmol/L 2,4-dinitrophenol (165.1%), an inhibitor of generation of energy-rich phosphates. Conclusion: The artificial amino acid 4-125I-mTyr demonstrated high metabolic stability, rapid blood clearance, rapid urinary excretion, and similar biodistribution to other radioiabeled L-Tyr analogs. 4-125I-mTyr can be a competitive substrate of L-Tyr reabsorption. However, 4-125I-mTyr demonstrates different pharmacologic features than those of 125I-IMT, particularly in renal handling. 4-125I-mTyr may potentially be applied as a new amino acid transport marker

    A Radiobrominated Tyrosine Kinase Inhibitor for EGFR with L858R/T790M Mutations in Lung Carcinoma.

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    Activating double mutations L858R/T790M in the epidermal growth factor receptor(EGFR) region are often observed as the cause of resistance to tyrosine kinase inhibitors (TKIs). Third-generation EGFR-TKIs, such as osimertinib and rociletinib (CO-1686), was developed to target such resistance mutations. The detection of activating L858R/T790M mutations is necessary to select sensitive patients for therapy. Hence, we aimed to develop novel radiobromine-labeled CO-1686 as apositron emission tomography (PET) imaging probe for detecting EGFR L858R/T790M mutations. Nonradioactive brominated-CO1686 (BrCO1686) was synthesized by the condensation of N-(3-[{2-chloro-5-(trifluoromethyl)pyrimidin-4-yl}amino]-5-bromophenyl) acrylamide with the corresponding substituted 1-(4-[4-amino-3-methoxyphenyl]piperazine-1-yl)ethan-1-one. The radiobrominated [77Br]BrCO1686 was prepared through bromodestannylation of the corresponding tributylstannylated precursor with [77Br]bromide and N-chlorosuccinimide. Although we aimed to provide a novel PET imaging probe, 77Br was used as an alternative radionuclide for 76Br. We fundamentally evaluated the potency of [77Br]BrCO1686 as a molecular probe for detecting EGFR L858R/T790M using human non-small-cell lung cancer (NSCLC) cell lines: H1975 (EGFR L858R/T790M), H3255 (EGFR L858R), and H441 (wild-type EGFR). The BrCO1686 showed high cytotoxicity toward H1975 (IC50 0.18 0.06 M) comparable to that of CO-1686 (IC50 0.14 0.05 M). In cell uptake experiments, the level of accumulation of [77Br]BrCO1686 in H1975 was significantly higher than those in H3255 and H441 upon 4 h of incubation. The radioactivity of [77Br]BrCO1686 (136.3% dose/mg protein) was significantly reduced to 56.9% dose/mg protein by the pretreatment with an excess CO-1686. These results indicate that the binding site of the radiotracers should be identical to that of CO-1686. The in vivo accumulation of radioactivity of [77Br]BrCO1686 in H1975 tumor (4.51 0.17) was higher than that in H441 tumor (3.71 0.13) 1 h postinjection. Our results suggested that [77Br]BrCO1686 has specificity toward NSCLC cells with double mutations EGFR L858R/T790M compared to those in EGFR L858R and wild-type EGFR. However, the in vivo accumulation of radioactivity in the targeted tumor needs to be optimized by structural modification

    Evaluation of transporter-mediated hepatobiliary transport of newly developed ¹⁸F-labeled pitavastatin derivative, PTV-F1, in rats by PET imaging

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    Quantitative evaluations of the functions of uptake and efflux transporters directly in vivo is desired to understand an efficient hepatobiliary transport of substrate drugs. Pitavastatin is a substrate of organic anion transporting polypeptides (OATPs) and canalicular efflux transporters; thus, it can be a suitable probe for positron-emission tomography (PET) imaging of hepatic transporter functions. To characterize the performance of [¹⁸F]PTV-F1, an analogue of pitavastatin, we investigated the impact of rifampicin (a typical OATP inhibitor) coadministration or Bcrp (breast cancer resistance protein) knockout on [¹⁸F]PTV-F1 hepatic uptake and efflux in rats by PET imaging. After intravenous administration, [¹⁸F]PTV-F1 selectively accumulated in the liver, and the radioactivity detected in plasma, liver, and bile mainly derived from the parent PTV-F1 during the PET study (∼40 min). Coadministration of rifampicin largely decreased the hepatic uptake of [¹⁸F]PTV-F1 by 73%. Because of its lower clearance in rats, [¹⁸F]PTV-F1 is more sensitive for monitoring changes in hepatic OATP1B function that other previously reported OATP1B PET probes. Rifampicin coadministration also significantly decreased the biliary excretion of radioactivity by 65%. Bcrp knockout did not show a significant impact on its biliary excretion.[¹⁸F]PTV-F1 enables quantitative analysis of the hepatobiliary transport system for organic anions

    In vivo radioactive metabolite analysis for individualized medicine: A basic study of a new method of CYP activity assay using 123I-IMP

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    Introduction: 123I-N-isopropyl-p-iodoamphetamine (123I-IMP) is metabolized and converted to 123I-p-iodoamphetamine (123I-PIA) by CYP2C19 in humans. Since variations in 123I-PIA levels reflect variations in CYP2C19 activity, CYP2C19 activity can be estimated by quantitative analysis of 123I-PIA levels. Thus, 123I-IMP administration can provide diagnostic information not only regarding cerebral blood flow (rCBF) but also regarding metabolic function. The aim of the present study was to detect variations in CYP activity in mice using metabolite analysis. Methods: Metabolism of 125I-IMP in pooled homogenates of mouse liver (MLH) was analyzed by high-performance liquid chromatography (HPLC) in the presence or absence of NADPH. The amount of 125I-PIA generated was calculated as the normalized peak area of the chromatogram. Inhibition of 125I-IMP metabolism was evaluated using the inhibitor SKF-525A. A biodistribution study of 125I-IMP was performed to determine the organ distribution of 125I-IMP/125I-IMP metabolites and the effect of SKF-525A. Variations in CYP activity in vivo were detected by administration of 123I-IMP and/or SKF-525A to mice. The liver and the kidney were then excised, homogenized and analyzed using HPLC. Results: 125I-IMP was metabolized by MLH in the presence of NADPH, and the production of 125I-PIA was inhibited by SKF-525A. SKF-525A did not greatly affect the biodistribution of 125I-IMP/125I-IMP metabolites in vivo. Both 123I-IMP and 123I-PIA were detected in organs of control mice. However, 123I-PIA was not detected in the livers or kidneys of mice treated with SKF-525A. Conclusions: CYP activity in vivo was inhibited by SKF-525A treatment. Variations in CYP activity could be detected in the blood, liver and kidney as changes in the peak area of 123I-PIA. Advances in knowledge and implications for patient care: 123I-IMP metabolite analysis has the potential to provide beneficial information for prediction of the effect of medicines, in addition to its contribution to more accurate rCBF diagnosis that reflects individual CYP activity

    123I-iomazenil whole-body imaging to detect hepatic carboxylesterase drug-metabolizing enzyme activity

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    OBJECTIVES: Drugs are mainly metabolized by hepatic enzymes, the activity of which can differ between individuals. Although it is ideal to measure the hepatic clearance of liver-targeted drugs in individualized medicine, blood enzyme tests typically measure metabolic drug clearance in the entire body, and not just in the liver. We investigated whether I-iomazenil imaging can directly assess and quantify the activity of hepatic drug-metabolizing enzymes. MATERIALS AND METHODS: Hepatic enzymes that metabolize I-iomazenil were identified by thin-layer chromatography in mouse liver homogenates with bis(4-nitrophenyl) phosphate (BNPP) inhibitor for carboxylesterase enzymes and nicotinamide adenine dinucleotide phosphate (NADPH) generator for cytochrome P450 enzymes. Whole-body images of mice were acquired using I-iomazenil with and without BNPP, and the distribution was also obtained. The metabolism of I-iomazenil in the blood, liver, gall bladder, and bladder was investigated by thin-layer chromatography. RESULTS: From the in-vitro metabolism of I-iomazenil using BNPP, the enzyme converting I-iomazenil to I-R-COOH was identified as carboxylesterase, and that converting I-iomazenil to M2 was identified as cytochrome P450 in experiments with and without an NADPH generator. The biological distribution and whole-body imaging showed increased accumulation in the liver of mice administered BNPP compared with normal mice, but decreased levels in the gall bladder and small intestine. The main fraction in bile and urine was I-R-COOH, with two unknown metabolites (M1 and M2), I, and I-iomazenil also being present. CONCLUSION: I-iomazenil whole-body imaging has good possibility of direct measurement of hepatic carboxylesterase activity as accumulation of I-R-COOH in the gall bladder through bile and in the bladder through urine

    Translocator protein imaging with 18F-FEDAC-positron emission tomography in rabbit atherosclerosis and its presence in human coronary vulnerable plaques

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    Background and aims: This study aimed to investigate whether N-benzyl-N-methyl-2-[7,8-dihydro-7-(2-[18F]fluoroethyl)-8-oxo-2-phenyl-9H-purin-9-yl]acetamide (18F-FEDAC), a probe for translocator protein (TSPO), can visualize atherosclerotic lesions in rabbits and whether TSPO is localized in human coronary plaques.Methods: 18F-FEDAC-PET of a rabbit model of atherosclerosis induced by a 0.5% cholesterol diet and ballooninjury of the left carotid artery (n = 7) was performed eight weeks after the injury. The autoradiography intensity of 18F-FEDAC in carotid artery tissue sections was measured, and TSPO expression was evaluated immunohistochemically.TSPO expression was examined in human coronary arteries obtained from autopsy cases (n = 16), and in human coronary plaques (n = 12) aspirated from patients with acute myocardial infarction (AMI).Results: 18F-FEDAC-PET visualized the atherosclerotic lesions in rabbits as high-uptake areas, and the standard uptake value was higher in injured arteries (0.574 ± 0.24) than in uninjured arteries (0.277 ± 0.13, p < 0.05) or myocardium (0.189 ± 0.07, p < 0.05). Immunostaining showed more macrophages and more TSPO expression in atherosclerotic lesions than in uninjured arteries. TSPO was localized in macrophages, and arterial autoradiography intensity was positively correlated with macrophage concentration (r = 0.64) and TSPO (r = 0.67). TSPO expression in human coronary arteries was higher in AMI cases than in non-cardiac death, or in the vulnerable plaques than in early or stable lesions, respectively. TSPO was localized in macrophages in all aspirated coronary plaques with thrombi.Conclusions: 18F-FEDAC-PET can visualize atherosclerotic lesions, and TSPO-expression may be a marker of highrisk coronary plaques

    Synthesis and fundamental evaluation of radioiodinated rociletinib (CO-1686) as a probe to lung cancer with L858R/T790M mutations of Epidermal Growth Factor Receptor (EGFR)

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    金沢大学疾患モデル総合研究センターRociletinib (CO-1686), a 2,4-diaminopyrimidine derivative, is a highly potent tyrosine kinase inhibitor (TKI) that acts on epidermal growth factor receptor (EGFR) with L858R/T790M mutations. We supposed radioiodinated CO-1686 would function as a useful tool for monitoring EGFR L858R/T790M mutations. To aid in patient selection before therapy with EGFR-TKIs, this study aimed to develop a 125I-labeled derivative of CO-1686, N-{3-[(2-{[4-(4-acetylpiperazin-1-yl)-2-methoxyphenyl]amino}-5-(trifluoromethyl)pyrimidine-4-yl] amino}-5-([125I]iodophenyl)acrylamide ([125I]ICO1686) and evaluate its selectivity toward EGFR L858R/T790M. Radiosynthesis was performed by iododestannylation of the corresponding tributylstannyl precursor with [125I]NaI and N-chlorosuccinimide. The selectivity of the tracer for detecting EGFR L858R/T790M was evaluated using three relevant non-small cell lung cancer (NSCLC) cell lines—H1975, H3255 and H441 overexpressing the dual mutation EGFR L858R/T790M, active mutant EGFR L858R and wild-type EGFR, respectively. The nonradioactive ICO1686 and the precursor compound were successfully synthesized. A novel radiolabeled probe, [125I]ICO1686, was prepared with high radiochemical yield (77%) and purity (>99%). ICO1686 exhibited high cytotoxicity toward H1975 (IC50 0.20 ± 0.05 µM) and H3255 (IC50 0.50 ± 0.21 µM), which is comparable to that of CO-1686. In contrast, the cytotoxicity of ICO1686 toward H441 was 10-fold lower than that toward H1975. In the cell uptake study, the radioactivity uptake of [125I]ICO1686 in H1975 was 101.52% dose/mg, whereas the uptakes in H3255 and H441 were 33.52 and 8.95% dose/mg, respectively. The uptake of [125I]ICO1686 in H1975 was greatly reduced to 45.61% dose/mg protein by treatment with excess CO-1686. In vivo biodistribution study of the radiotracer found that its accumulation in H1975 tumor (1.77 ± 0.43% ID/g) was comparable to that in H3255 tumor (1.63 ± 0.23% ID/g) and the accumulation in H1975 tumor was not reduced by pretreatment with an excess dose of CO-1686. Although this radiotracer exhibited highly specific in vitro uptake in target cancer cells, structural modification is required to improve in vivo biodistribution. © 2020 by the authors.This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited

    A radiobrominated tyrosine kinase inhibitor for egfr with l858r/t790m mutations in lung carcinoma

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    金沢大学疾患モデル総合研究センターActivating double mutations L858R/T790M in the epidermal growth factor receptor (EGFR) region are often observed as the cause of resistance to tyrosine kinase inhibitors (TKIs). Third‐generation EGFR‐TKIs, such as osimertinib and rociletinib (CO‐1686), was developed to target such resistance mutations. The detection of activating L858R/T790M mutations is necessary to select sensitive patients for therapy. Hence, we aimed to develop novel radiobromine‐labeled CO‐ 1686 as a positron emission tomography (PET) imaging probe for detecting EGFR L858R/T790M mutations. Nonradioactive brominated‐CO1686 (BrCO1686) was synthesized by the condensation of N‐(3‐[{2‐chloro‐5‐(trifluoromethyl)pyrimidin‐4‐yl}amino]‐5‐bromophenyl) acrylamide with the corresponding substituted 1‐(4‐[4‐amino‐3‐methoxyphenyl]piperazine‐1‐yl)ethan‐1‐one. The radi-obrominated [77 Br]BrCO1686 was prepared through bromodestannylation of the corresponding tributylstannylated precursor with [77Br]bromide and N‐chlorosuccinimide. Although we aimed to provide a novel PET imaging probe,77Br was used as an alternative radionuclide for76Br. We fun-damentally evaluated the potency of [77Br]BrCO1686 as a molecular probe for detecting EGFR L858R/T790M using human non‐small‐cell lung cancer (NSCLC) cell lines: H1975 (EGFR L858R/T790M), H3255 (EGFR L858R), and H441 (wild‐type EGFR). The BrCO1686 showed high cy-totoxicity toward H1975 (IC50 0.18 ± 0.06 μM) comparable to that of CO‐1686 (IC50 0.14 ± 0.05 μM). In cell uptake experiments, the level of accumulation of [77Br]BrCO1686 in H1975 was significantly higher than those in H3255 and H441 upon 4 h of incubation. The radioactivity of [77Br]BrCO1686 (136.3% dose/mg protein) was significantly reduced to 56.9% dose/mg protein by the pretreatment with an excess CO‐1686. These results indicate that the binding site of the radiotracers should be identical to that of CO‐1686. The in vivo accumulation of radioactivity of [77Br]BrCO1686 in H1975 tumor (4.51 ± 0.17) was higher than that in H441 tumor (3.71 ± 0.13) 1 h postinjection. Our results suggested that [77Br]BrCO1686 has specificity toward NSCLC cells with double mutations EGFR L858R/T790M compared to those in EGFR L858R and wild‐type EGFR. However, the in vivo accumulation of radioactivity in the targeted tumor needs to be optimized by structural modification. © 2021 by the authors. Licensee MDPI, Basel, Switzerland.CC-BY 4.
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