91 research outputs found
13C/15N‐Enriched L‐Dopa as a Triple‐Resonance NMR Probe to Monitor Neurotransmitter Dopamine in the Brain and Liver Extracts of Mice
In an attempt to monitor μM-level trace constituents, we applied here 1H-{13C-15N} triple-resonance nuclear magnetic resonance (NMR) to 13C/15N-enriched L-Dopa as the inevitable precursor of the neurotransmitter dopamine in the brain. The perfect selectivity (to render endogenous components silent) and μM-level sensitivity (700 MHz spectrometer equipped with a cryogenic probe) of triple-resonance allowed the unambiguous and quantitative metabolic and pharmacokinetic analyses of administered L-Dopa/dopamine in the brain and liver of mice. The level of dopamine generated in the brain (within the range 7–76 μM, which covers the typical stimulated level of ~30 μM) could be clearly monitored ex vivo, but was slightly short of the detection limit of a 7T MR machine for small animals. This work suggests that μM-level trace constituents are potential targets of ex vivo monitoring as long as they contain N atom(s) and their appropriate 13C/15N-enrichment is synthetically accessible
Pharmacokinetics of Chiral Dendrimer-Triamine-Coordinated Gd-MRI Contrast Agents Evaluated by in Vivo MRI and Estimated by in Vitro QCM
Recently, we developed novel chiral dendrimer-triamine-coordinated Gd-MRI contrast agents (Gd-MRI CAs), which showed longitudinal relaxivity (r1) values about four times higher than that of clinically used Gd-DTPA (Magnevist®, Bayer). In our continuing study of pharmacokinetic differences derived from both the chirality and generation of Gd-MRI CAs, we found that the ability of chiral dendrimer Gd-MRI CAs to circulate within the body can be directly evaluated by in vitro MRI (7 T). In this study, the association constants (Ka) of chiral dendrimer Gd-MRI CAs to bovine serum albumin (BSA), measured and calculated with a quartz crystal microbalance (QCM) in vitro, were found to be an extremely easy means for evaluating the body-circulation ability of chiral dendrimer Gd-MRI CAs. The Ka values of S-isomeric dendrimer Gd-MRI CAs were generally greater than those of R-isomeric dendrimer Gd-MRI CAs, which is consistent with the results of our previous MRI study in vivo
Overexpression of the adiponectin gene mimics the metabolic and stress resistance effects of calorie restriction, but not the anti-tumor effect
Adiponectin (Adipoq), a peptide hormone secreted from the white adipose tissue, may play a role in the anti-aging and/or anti-tumor effects of calorie restriction (CR). We analyzed metabolic traits in Adipoq gene-overexpressing mice fed ad libitum with a regular diet (RD) or a high-fat diet (HFD), or fed 30% CR of RD initiated at 12. weeks of age. Adipoq-RD and -HFD mice at 6. months of age showed reduced blood glucose and insulin concentrations, and thus increased insulin sensitivity, compared with WT mice fed a RD or a HFD. In the epididymal white adipose tissue in Adipoq mice, senescence-like changes such as upregulation of p53 protein and of biomarkers of inflammation, Cd68 and Ccl2 mRNA, were ameliorated compared with WT-RD and WT-HFD mouse tissues. Resistance to stress induced by lipopolysaccharide was also strengthened in Adipoq mice compared with WT mice. These metabolic changes and stress resistance were also noted in the WT-CR mice, suggesting that Adipoq plays a part in the effect of CR. In contrast, in an allograft tumor growth model, tumor growth was not inhibited in Adipoq mice. The present findings suggest that Adipoq plays a part in the anti-aging, but not in the anti-tumor, effects of CR
New findings on the fungal species Tricholoma matsutake from Ukraine, and revision of its taxonomy and biogeography based on multilocus phylogenetic analyses
Publisher Copyright: © 2022 Elsevier B.V.. All rights reserved.Matsutake mushrooms are among the best-known edible wild mushroom taxa worldwide. The representative Tricholoma matsutake is from East Asia and the northern and central regions of Europe. Here, we report the existence of T. matsutake under fir trees in Eastern Europe (i.e., Ukraine), as confirmed by phylogenetic analysis of nine loci on the nuclear and mitochondrial genomes. All specimens from Japan, Bhutan, China, North Korea, South Korea, Sweden, Finland, and Ukraine formed a T. matsutake clade according to the phylogeny of the internal transcribed spacer region. The European population of T. matsutake was clustered based on the β2 tubulin gene, with a moderate bootstrap value. In contrast, based on analyses of three loci, i.e., rpb2, tef1, and the β2 tubulin gene, T. matsutake specimens sampled from Bhutan and China belonged to a clade independent of the other specimens of this species, implying a genetically isolated population. As biologically available type specimens of T. matsutake have not been designated since its description as a new species from Japan in 1925, we established an epitype of this fungus, sampled in a Pinus densiflora forest in Nagano, Japan.Peer reviewe
Met Kinase Inhibitor E7050 Reverses Three Different Mechanisms of Hepatocyte Growth Factor-induced Tyrosine Kinase Inhibitor Resistance in EGFR Mutant Lung Cancer
PURPOSE: Hepatocyte growth factor (HGF) induces resistance to reversible and irreversible epidermal growth factor receptor tyrosine kinase inhibitors (EGFR-TKIs) in EGFR mutant lung cancer cells by activating Met and the downstream PI3K/Akt pathway. Moreover, continuous exposure to HGF accelerates the emergence of EGFR-TKI-resistant clones. We assayed whether a new Met kinase inhibitor, E7050, which is currently being evaluated in clinical trials, could overcome these three mechanisms of resistance to EGFR-TKIs. EXPERIMENTAL DESIGN: The effects of E7050 on HGF-induced resistance to reversible (gefitinib), irreversible (BIBW2992), and mutant-selective (WZ4002) EGFR-TKIs were determined using the EGFR-mutant human lung cancer cell lines PC-9 and HCC827 with an exon 19 deletion, and H1975 with an T790M secondary mutation. PC-9 cells were mixed with HGF-producing fibroblasts, MRC-5 cells, and subcutaneously inoculated into SCID mice and the therapeutic effects of E7050 plus gefitinib were assayed. RESULTS: E7050 circumvented resistance to all of the reversible, irreversible, and mutant-selective EGFR-TKIs induced by exogenous and/or endogenous HGF in EGFR mutant lung cancer cell lines, by blocking the Met/Gab1/PI3K/Akt pathway in vitro. E7050 also prevented the emergence of gefitinib-resistant HCC827 cells induced by continuous exposure to HGF. In the in vivo model, E7050 plus gefitinib resulted in marked regression of tumor growth associated with inhibition of Akt phosphorylation in cancer cells. CONCLUSIONS: A new Met kinase inhibitor, E7050, reverses the three HGF-induced mechanisms of gefitinib resistance, suggesting that E7050 may overcome HGF-induced resistance to gefitinib and next-generation EGFR-TKIs
Kinetic resolution of vic-amino alcohols catalyzed by a chiral Cu(II) complex
Kinetic resolution of N-benzoylated vic-amino alcohols was achieved by benzoylation in the presence of copper triflate and (R,R)-Ph-BOX as catalysts. The observed enantioselectivity was moderate to high. The method was applied to a kinetic resolution of racemic prolinol and piperidinemethanol derivatives as well as an asymmetric desymmetrization of 2-amino-1,3-diol derivatives
In Vivo Tracking of Transplanted Mononuclear Cells Using Manganese-Enhanced Magnetic Resonance Imaging (MEMRI)
BACKGROUND: Transplantation of mononuclear cells (MNCs) has previously been tested as a method to induce therapeutic angiogenesis to treat limb ischemia in clinical trials. Non-invasive high resolution imaging is required to track the cells and evaluate clinical relevance after cell transplantation. The hypothesis that MRI can provide in vivo detection and long-term observation of MNCs labeled with manganese contrast-agent was investigated in ischemic rat legs. METHODS AND FINDINGS: The Mn-labeled MNCs were evaluated using 7-tesla high-field magnetic resonance imaging (MRI). Intramuscular transplanted Mn-labeled MNCs were visualized with MRI for at least 7 and up to 21 days after transplantation in the ischemic leg. The distribution of Mn-labeled MNCs was similar to that of ¹¹¹In-labeled MNCs measured with single-photon emission computed tomography (SPECT) and DiI-dyed MNCs with fluorescence microscopy. In addition, at 1-2 days after transplantation the volume of the site injected with intact Mn-labeled MNCs was significantly larger than that injected with dead MNCs, although the dead Mn-labeled MNCs were also found for approximately 2 weeks in the ischemic legs. The area covered by CD31-positive cells (as a marker of capillary endothelial cells) in the intact Mn-MNCs implanted site at 43 days was significantly larger than that at a site implanted with dead Mn-MNCs. CONCLUSIONS: The present Mn-enhanced MRI method enabled visualization of the transplanted area with a 150-175 µm in-plane spatial resolution and allowed the migration of labeled-MNCs to be observed for long periods in the same subject. After further optimization, MRI-based Mn-enhanced cell-tracking could be a useful technique for evaluation of cell therapy both in research and clinical applications
A nationwide, multi-center, retrospective study of symptomatic small bowel stricture in patients with Crohn\u27s disease.
BACKGROUND:Small bowel stricture is one of the most common complications in patients with Crohn\u27s disease (CD). Endoscopic balloon dilatation (EBD) is a minimally invasive treatment intended to avoid surgery; however, whether EBD prevents subsequent surgery remains unclear. We aimed to reveal the factors contributing to surgery in patients with small bowel stricture and the factors associated with subsequent surgery after initial EBD.METHODS:Data were retrospectively collected from surgically untreated CD patients who developed symptomatic small bowel stricture after 2008 when the use of balloon-assisted enteroscopy and maintenance therapy with anti-tumor necrosis factor (TNF) became available.RESULTS:A total of 305 cases from 32 tertiary referral centers were enrolled. Cumulative surgery-free survival was 74.0% at 1 year, 54.4% at 5 years, and 44.3% at 10 years. The factors associated with avoiding surgery were non-stricturing, non-penetrating disease at onset, mild severity of symptoms, successful EBD, stricture length < 2 cm, and immunomodulator or anti-TNF added after onset of obstructive symptoms. In 95 cases with successful initial EBD, longer EBD interval was associated with lower risk of surgery. Receiver operating characteristic analysis revealed that an EBD interval of ≤ 446 days predicted subsequent surgery, and the proportion of smokers was significantly high in patients who required frequent dilatation.CONCLUSIONS:In CD patients with symptomatic small bowel stricture, addition of immunomodulator or anti-TNF and smoking cessation may improve the outcome of symptomatic small bowel stricture, by avoiding frequent EBD and subsequent surgery after initial EBD
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