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941.
Yeon-hee Kim Wook-jin Ra Solyi Cho Shinai Choi Bokyung Soh Yongsung Joo Kwang-Won Lee 《Molecules (Basel, Switzerland)》2021,26(21)
Thallium (Tl) is a rare element and one of the most harmful metals. This study validated an analytical method for determining Tl in foods by inductively coupled plasma mass spectrometry (ICP-MS) based on food matrices and calories. For six representative foods, the method’s correlation coefficient (R2) was above 0.999, and the method limit of detection (MLOD) was 0.0070–0.0498 μg kg−1, with accuracy ranging from 82.06% to 119.81% and precision within 10%. We investigated 304 various foods in the South Korean market, including agricultural, fishery, livestock, and processed foods. Tl above the MLOD level was detected in 148 samples and was less than 10 μg kg−1 in 98% of the samples. Comparing the Tl concentrations among food groups revealed that fisheries and animal products had higher Tl contents than cereals and vegetables. Tl exposure via food intake did not exceed the health guidance level. 相似文献
942.
The effect of solvent type on the structural features of PVC gels prepared from the solutions of dibutyl phthalate(DBP) and butyl benzoate(BB) were investigated. The influence of solvent type, i.e., diester solvent or monoester solvent, on the mechanical responses was characterized by dynamic viscoelastic measurements as a function of temperature, aging time, and PVC concentration. In the case of PVC/DBP aged gels, the transition phenomenon appeared close to 50°C, whereas no such transitions were observed for PVC/BB aged gels. This transition is considered to be associated with polymer‐solvent complex which can be accounted for electrostatic interaction between C=O bond of solvent and H‐C‐Cl part of PVC. While BB solvent molecules can not form polymer‐solvent complex due to no capacity to act as a bridge between PVC molecular chains. FT‐IR spectroscopy and DSC investigation on either PVC/DBP gels or PVC/BB gels was reported and discussed together with the mechanical behavior. Electron micrographs of the dried gel prepared from the critical point drying technique reveal that the gel morphology consists of well developed three dimensional fibrous network structure independent of solvent type. 相似文献
943.
(1)H-MRS metabolic patterns for distinguishing between meningiomas and other brain tumors 总被引:14,自引:0,他引:14
Yet meningiomas have characteristic neuroimaging features, some other lesions are still confusing with meningiomas. The aim of this study was trying to find the typical (1)H-MRS metabolic factors of histologic subtyped meningiomas, schwannomas, metastases, and other brain tumors for differential diagnosis among them. (1)H-MRS using STEAM (TE/30 ms, TR/2 sec) and PRESS (TE/288 ms, TR/2 sec) sequences were performed on 44 untreated brain tumors. Obtained metabolic patterns from the typical spectra of meningioma, schwannoma, metastasis were compared with each other or other brain tumors to evaluate the usefulness for diagnosis between them. Alanine(Ala) was observed in 15 cases of the 19 meningiomas with a little variation to three histologic subtypes, while minimal lipids were observed in every 19 meningiomas. Elevated glutamate/glutamine(Glx) was detected in 12 cases of the meniningiomas. Increased myo-inositol(mI) was detected in 11 cases of the 13 schwannomas. Dominant lipids signals as well as long-T2 lipids were detected in every metastasis in conjunction with elevated choline (Cho). Enhanced Glx was observed in 4 cases of the 8 metastases without correlation of primary tumor site or types. Hemangiopericytoma showed different spectral patterns from typical meningiomas: only dominant Cho, minimal lipids and absence of Ala or Glx signals. These metabolic patterns in typical tumors may provide a basis for differential diagnosis (average value of chi(2) = 23.33, p < 0.01) between meningiomas and schwannomas as well as metastases. However proton spectral distinction among the different histologic subtypes of meningiomas was not definite. 相似文献
944.
Haejeong Heo Jong-Hwan Kim Hyun Jung Lim Jeong-Hwan Kim Miso Kim Jaemoon Koh Joo-Young Im Bo-Kyung Kim Misun Won Ji-Hwan Park Yang-Ji Shin Mi Ran Yun Byoung Chul Cho Yong Sung Kim Seon-Young Kim Mirang Kim 《Experimental & molecular medicine》2022,54(8):1236
Acquired resistance to inhibitors of anaplastic lymphoma kinase (ALK) is a major clinical challenge for ALK fusion-positive non-small-cell lung cancer (NSCLC). In the absence of secondary ALK mutations, epigenetic reprogramming is one of the main mechanisms of drug resistance, as it leads to phenotype switching that occurs during the epithelial-to-mesenchymal transition (EMT). Although drug-induced epigenetic reprogramming is believed to alter the sensitivity of cancer cells to anticancer treatments, there is still much to learn about overcoming drug resistance. In this study, we used an in vitro model of ceritinib-resistant NSCLC and employed genome-wide DNA methylation analysis in combination with single-cell (sc) RNA-seq to identify cytidine deaminase (CDA), a pyrimidine salvage pathway enzyme, as a candidate drug target. CDA was hypomethylated and upregulated in ceritinib-resistant cells. CDA-overexpressing cells were rarely but definitively detected in the naïve cell population by scRNA-seq, and their abundance was increased in the acquired-resistance population. Knockdown of CDA had antiproliferative effects on resistant cells and reversed the EMT phenotype. Treatment with epigenome-related nucleosides such as 5-formyl-2′-deoxycytidine selectively ablated CDA-overexpressing resistant cells via accumulation of DNA damage. Collectively, our data suggest that targeting CDA metabolism using epigenome-related nucleosides represents a potential new therapeutic strategy for overcoming ALK inhibitor resistance in NSCLC.Subject terms: Gene expression, Epigenomics, Non-small-cell lung cancer 相似文献
945.
Soonbum Park Eun A Cho Jung Nyeo Chun Da Young Lee Sanghoon Lee Mi Yeon Kim Sang Mun Bae Su In Jo So Hee Lee Hyun Ho Park Tae Min Kim Insuk So Sang-Yeob Kim Ju-Hong Jeon 《Experimental & molecular medicine》2022,54(8):1225
Crizotinib is a clinically approved tyrosine kinase inhibitor for the treatment of patients with locally advanced or metastatic non-small cell lung cancer (NSCLC) harboring EML4-ALK fusion. Crizotinib was originally developed as an inhibitor of MET (HGF receptor), which is involved in the metastatic cascade. However, little is known about whether crizotinib inhibits tumor metastasis in NSCLC cells. In this study, we found that crizotinib suppressed TGFβ signaling by blocking Smad phosphorylation in an ALK/MET/RON/ROS1-independent manner in NSCLC cells. Molecular docking and in vitro enzyme activity assays showed that crizotinib directly inhibited the kinase activity of TGFβ receptor I through a competitive inhibition mode. Cell tracking, scratch wound, and transwell migration assays showed that crizotinib simultaneously inhibited TGFβ- and HGF-mediated NSCLC cell migration and invasion. In addition, in vivo bioluminescence imaging analysis showed that crizotinib suppressed the metastatic capacity of NSCLC cells. Our results demonstrate that crizotinib attenuates cancer metastasis by inhibiting TGFβ signaling in NSCLC cells. Therefore, our findings will help to advance our understanding of the anticancer action of crizotinib and provide insight into future clinical investigations.Subject terms: Non-small-cell lung cancer, Targeted therapies 相似文献
946.
Jae-Kwon Jo Gihyun Lee Cong Duc Nguyen Seong-Eun Park Eun-Ju Kim Hyun-Woo Kim Seung-Ho Seo Kwang-Moon Cho Sun Jae Kwon Jae-Hong Kim Hong-Seok Son 《Molecules (Basel, Switzerland)》2022,27(19)
Accumulated clinical and biomedical evidence indicates that the gut microbiota and their metabolites affect brain function and behavior in various central nervous system disorders. This study was performed to investigate the changes in brain metabolites and composition of the fecal microbial community following injection of amyloid β (Aβ) and donepezil treatment of Aβ-injected mice using metataxonomics and metabolomics. Aβ treatment caused cognitive dysfunction, while donepezil resulted in the successful recovery of memory impairment. The Aβ + donepezil group showed a significantly higher relative abundance of Verrucomicrobia than the Aβ group. The relative abundance of 12 taxa, including Blautia and Akkermansia, differed significantly between the groups. The Aβ + donepezil group had higher levels of oxalate, glycerol, xylose, and palmitoleate in feces and oxalate, pyroglutamic acid, hypoxanthine, and inosine in brain tissues than the Aβ group. The levels of pyroglutamic acid, glutamic acid, and phenylalanine showed similar changes in vivo and in vitro using HT-22 cells. The major metabolic pathways in the brain tissues and gut microbiota affected by Aβ or donepezil treatment of Aβ-injected mice were related to amino acid pathways and sugar metabolism, respectively. These findings suggest that alterations in the gut microbiota might influence the induction and amelioration of Aβ-induced cognitive dysfunction via the gut–brain axis. This study could provide basic data on the effects of Aβ and donepezil on gut microbiota and metabolites in an Aβ-induced cognitive impairment mouse model. 相似文献
947.
Chao-Hsuan Chen Pei-Chen Hsu Shih-Wei Hsu Kun-Ting Hong Kai-Yuan Chen Jie-Long He Der-Yang Cho Yun-Chi Wang Wen-Shin Chang Da-Tian Bau Chia-Wen Tsai 《Molecules (Basel, Switzerland)》2022,27(13)
6-hydroxydopamine (6-OHDA) is used to induce oxidative damage in neuronal cells, which can serve as an experimental model of Parkinson’s disease (PD). Jujuboside A and B confer free radical scavenging effects but have never been examined for their neuroprotective effects, especially in PD; therefore, in this study, we aimed to investigate the feasibility of jujubosides as protectors of neurons against 6-OHDA and the underlying mechanisms. 6-OHDA-induced neurotoxicity in the human neuronal cell lines SH-SY5Y and SK-N-SH, was used to evaluate the protective effects of jujubosides. These findings indicated that jujuboside A and B were both capable of rescuing the 6-OHDA-induced loss of cell viability, activation of apoptosis, elevation of reactive oxygen species, and downregulation of the expression levels of superoxide dismutase, catalase, and glutathione peroxidase. In addition, jujuboside A and B can reverse a 6-OHDA-elevated Bax/Bcl-2 ratio, downregulate phosphorylated PI3K and AKT, and activate caspase-3, -7, and -9. These findings showed that jujubosides were capable of protecting both SH-SY5Y and SK-N-SH neuronal cells from 6-OHDA-induced toxicity via the rebalancing of the redox system, together with the resetting of the PI3K/AKT apoptotic signaling cascade. In conclusion, jujuboside may be a potential drug for PD prevention. 相似文献
948.
Gi-Sang Seong Seong-Wook Seo Ji Young Cho Kye Wan Lee Beom-Jin Lee In-Soo Yoon Hyo-Eon Jin 《Molecules (Basel, Switzerland)》2022,27(24)
Leuprolide is a synthetic nonapeptide drug (pyroGlu-His-Trp-Ser-Tyr-d-Leu-Leu-Arg-Pro-NHEt) that acts as a gonadotropin-releasing hormone agonist. The continuous administration of therapeutic doses of leuprolide inhibits gonadotropin secretion, which is used in androgen-deprivation therapy for the treatment of advanced prostate cancer, central precocious puberty, endometriosis, uterine fibroids, and other sex-hormone-related conditions. To improve the pharmacokinetic properties of peptide drugs, a fatty acid was conjugated with leuprolide for long-term action. In this study, we developed a simple ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method for the simultaneous determination of leuprolide and leuprolide–oleic acid conjugate (LOC) levels. The developed method was validated in terms of linearity, precision, accuracy, recovery, matrix effect, and stability according to the US Food and Drug Administration guidelines, and the parameters were within acceptable limits. Subsequently, the pharmacokinetics of leuprolide and LOCs were evaluated. In vivo rat subcutaneous studies revealed that conjugation with fatty acids significantly altered the pharmacokinetics of leuprolide. After the subcutaneous administration of fatty-acid-conjugated leuprolide, the mean absorption time and half-life were prolonged. To the best of our knowledge, this is the first study showing the effects of fatty acid conjugates on the pharmacokinetics of leuprolide using a newly developed UPLC-MS/MS method for the simultaneous quantification of leuprolide and LOCs. 相似文献
949.
In Taek Choi Dr. Myung Jong Ju Sang Hyun Song Sang Gyun Kim Dr. Dae Won Cho Prof. Dr. Chan Im Prof. Dr. Hwan Kyu Kim 《Chemistry (Weinheim an der Bergstrasse, Germany)》2013,19(46):15545-15555
The Y‐shaped, low molecular mass, hole‐conductor (HC), acidic coadsorbents 4‐{3,7‐bis[4‐(2‐ethylhexyloxy)phenyl]‐10H‐phenothiazin‐10‐yl}benzoic acid ( PTZ1 ) and 4‐{3,7‐bis[4‐(2‐ethylhexyloxy)phenyl]‐10H‐phenothiazin‐10‐yl}biphenyl‐4‐carboxylic acid ( PTZ2 ) were developed. Owing to their tuned and negative‐shifted HOMO levels (vs. NHE), they were used as HC coadsorbents in dye‐sensitized solar cells (DSSCs) to improve cell performance through desired cascade‐type hole‐transfer processes. Their detailed functions as HC coadsorbents in DSSCs were investigated to obtain evidence for the desired cascade‐type hole‐transfer processes. They have multiple functions, such as preventing π–π stacking of dye molecules, harvesting light of shorter wavelengths, and faster dye regeneration. By using PTZ2 as the tailor‐made HC coadsorbent on the TiO2 surface with the organic dye NKX2677, an extremely high conversion efficiency of 8.95 % was achieved under 100 mW cm?2 AM 1.5G simulated light (short‐circuit current JSC=16.56 mA cm?2, open‐circuit voltage VOC=740 mV, and fill factor of 73 %). Moreover, JSC was increased by 13 %, VOC by 27 % and power‐conversion efficiency by 49 % in comparison to an NKX2677‐based DSSC without an HC coadsorbent. This is due to the HC coadsorbent having a HOMO energy level well matched to that of the NKX‐2677 dye to induce the desired cascade‐type hole‐transfer processes, which are associated with a slower charge recombination, fast dye regeneration, effective screening of liquid electrolytes, and an induced negative shift of the quasi‐Fermi level of the electrode. Thus, this new class of Y‐shaped, low molecular weight, organic, HC coadsorbents based on phenothiazine carboxylic acid derivatives hold promise for highly efficient organic DSSCs. 相似文献
950.
Reactions of ethylene with laser-ablated group 5 metal atoms in excess argon have been carried out during codeposition at 8 K, and the matrix infrared spectra of intermediate products have been investigated. Oxidative C-H insertion of the transition metal into a C-H bond occurs and beta-hydrogen transfer follows to form the dihydrido complexes (MH2-C2H2). In the Ta spectra, the dihydrido complex is the primary product, whereas the Nb and V spectra reveal absorptions from both the insertion (MH-C2H3) and dihydrido complexes. The insertion and dihydrido complexes identified here are in fact the reaction intermediates in the hydrogen elimination of ethylene proposed in previous reaction dynamics studies. Calculations also show that the higher oxidation-state complex becomes more stable relative to the insertion product going down the group 5 family. 相似文献