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排序方式: 共有1402条查询结果,搜索用时 296 毫秒
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2.
Dr. Tomasz Ratajczyk Prof. Dr. Gerd Buntkowsky Dr. Torsten Gutmann Dr. Bartłomiej Fedorczyk Dr. Adam Mames Dr. Mariusz Pietrzak Zuzanna Puzio Piotr Grzegorz Szkudlarek 《Chembiochem : a European journal of chemical biology》2021,22(5):855-860
The biorelevant PyFALGEA oligopeptide ligand, which is selective towards the epidermal growth factor receptor (EGFR), has been successfully employed as a substrate in magnetic resonance signal amplification by reversible exchange (SABRE) experiments. It is demonstrated that PyFALGEA and the iridium catalyst IMes form a PyFALGEA:IMes molecular complex. The interaction between PyFALGEA:IMes and H2 results in a ternary SABRE complex. Selective 1D EXSY experiments reveal that this complex is labile, which is an essential condition for successful hyperpolarization by SABRE. Polarization transfer from parahydrogen to PyFALGEA is observed leading to significant enhancement of the 1H NMR signals of PyFALGEA. Different iridium catalysts and peptides are inspected to discuss the influence of their molecular structures on the efficiency of hyperpolarization. It is observed that PyFALGEA oligopeptide hyperpolarization is more efficient when an iridium catalyst with a sterically less demanding NHC ligand system such as IMesBn is employed. Experiments with shorter analogues of PyFALGEA, that is, PyLGEA and PyEA, show that the bulky phenylalanine from the PyFALGEA oligopeptide causes steric hindrance in the SABRE complex, which hampers hyperpolarization with IMes. Finally, a single-scan 1H NMR SABRE experiment of PyFALGEA with IMesBn revealed a unique pattern of NMR lines in the hydride region, which can be treated as a fingerprint of this important oligopeptide. 相似文献
3.
Teresa Glomb Benita Wiatrak Katarzyna Gbczak Tomasz Gbarowski Dorota Bodetko aneta Czynikowska Piotr
witek 《International journal of molecular sciences》2020,21(23)
Numerous studies have confirmed the coexistence of oxidative stress and inflammatory processes. Long-term inflammation and oxidative stress may significantly affect the initiation of the neoplastic transformation process. Here, we describe the synthesis of a new series of Mannich base-type hybrid compounds containing an arylpiperazine residue, 1,3,4-oxadiazole ring, and pyridothiazine-1,1-dioxide core. The synthesis was carried out with the hope that the hybridization of different pharmacophoric molecules would result in a synergistic effect on their anti-inflammatory activity, especially the ability to inhibit cyclooxygenase. The obtained compounds were investigated in terms of their potencies to inhibit cyclooxygenase COX-1 and COX-2 enzymes with the use of the colorimetric inhibitor screening assay. Their antioxidant and cytotoxic effect on normal human dermal fibroblasts (NHDF) was also studied. Strong COX-2 inhibitory activity was observed after the use of TG6 and, especially, TG4. The TG11 compound, as well as reference meloxicam, turned out to be a preferential COX-2 inhibitor. TG12 was, in turn, a non-selective COX inhibitor. A molecular docking study was performed to understand the binding interaction of compounds at the active site of cyclooxygenases. 相似文献
4.
Tomasz Wasiewicz Paulina Szyszka Miroslawa Cichorek Zorica Janjetovic Robert C. Tuckey Andrzej T. Slominski Michal A. Zmijewski 《International journal of molecular sciences》2015,16(4):6645-6667
Deregulated melanogenesis is involved in melanomagenesis and melanoma progression and resistance to therapy. Vitamin D analogs have anti-melanoma activity. While the hypercalcaemic effect of the active form of Vitamin D (1,25(OH)2D3) limits its therapeutic use, novel Vitamin D analogs with a modified side chain demonstrate low calcaemic activity. We therefore examined the effect of secosteroidal analogs, both classic (1,25(OH)2D3 and 25(OH)D3), and novel relatively non-calcemic ones (20(OH)D3, calcipotriol, 21(OH)pD, pD and 20(OH)pL), on proliferation, colony formation in monolayer and soft-agar, and mRNA and protein expression by melanoma cells. Murine B16-F10 and hamster Bomirski Ab cell lines were shown to be effective models to study how melanogenesis affects anti-melanoma treatment. Novel Vitamin D analogs with a short side-chain and lumisterol-like 20(OH)pL efficiently inhibited rodent melanoma growth. Moderate pigmentation sensitized rodent melanoma cells towards Vitamin D analogs, and altered expression of key genes involved in Vitamin D signaling, which was opposite to the effect on heavily pigmented cells. Interestingly, melanogenesis inhibited ligand-induced Vitamin D receptor translocation and ligand-induced expression of VDR and CYP24A1 genes. These findings indicate that melanogenesis can affect the anti-melanoma activity of Vitamin D analogs in a complex manner. 相似文献
5.
Aleksandra Czumaj Sylwia Szrok-Jurga Areta Hebanowska Jacek Turyn Julian Swierczynski Tomasz Sledzinski Ewa Stelmanska 《International journal of molecular sciences》2020,21(23)
The importance of coenzyme A (CoA) as a carrier of acyl residues in cell metabolism is well understood. Coenzyme A participates in more than 100 different catabolic and anabolic reactions, including those involved in the metabolism of lipids, carbohydrates, proteins, ethanol, bile acids, and xenobiotics. However, much less is known about the importance of the concentration of this cofactor in various cell compartments and the role of altered CoA concentration in various pathologies. Despite continuous research on these issues, the molecular mechanisms in the regulation of the intracellular level of CoA under pathological conditions are still not well understood. This review summarizes the current knowledge of (a) CoA subcellular concentrations; (b) the roles of CoA synthesis and degradation processes; and (c) protein modification by reversible CoA binding to proteins (CoAlation). Particular attention is paid to (a) the roles of changes in the level of CoA under pathological conditions, such as in neurodegenerative diseases, cancer, myopathies, and infectious diseases; and (b) the beneficial effect of CoA and pantethine (which like CoA is finally converted to Pan and cysteamine), used at pharmacological doses for the treatment of hyperlipidemia. 相似文献
6.
X. Gong W. Ma J.C. Ostrowski K. Bechgaard G.C. Bazan A.J. Heeger S. Xiao D. Moses 《Advanced functional materials》2004,14(4):393-397
The electronic properties, carrier injection, and transport into poly(9,9‐dioctylfluorene) (PFO), PFO end‐capped with hole‐transporting moieties (HTM), PFO–HTM, and PFO end‐capped with electron‐transporting moieties (ETM), PFO–ETM, were investigated. The data demonstrate that charge injection and transport can be tuned by end‐capping with HTM and ETM, without significantly altering the electronic properties of the conjugated backbone. End‐capping with ETM resulted in more closely balanced charge injection and transport. Single‐layer electrophosphorescent light‐emitting diodes (LEDs), fabricated from PFO, PFO–HTM and PFO–ETM as hosts and tris[2,5‐bis‐2′‐(9′,9′‐dihexylfluorene)pyridine‐κ2NC3′]iridium(III ), Ir(HFP)3 as the guest, emitted red light with brightnesses of 2040 cd m–2, 1940 cd m–2 and 2490 cd m–2 at 290 mA cm–2 (16 V) and with luminance efficiencies of 1.4 cd A–1, 1.4 cd A–1 and 1.8 cd A–1 at 4.5 mA cm–2 for PFO, PFO–HTM, and PFO–ETM, respectively. 相似文献
7.
Summary The mass spectra of secondary ions emitted from PVK thin layers under 2 keV Xe+ bombardment were measured. The charasteristic elemental and molecular ions emitted were specified. The temperature dependence of the secondary emission was also measured. The results obtained were briefly discussed in terms of the ion beam-induced polymer structure fragmentation.Work supported by the research programme MR-I-5-8. 相似文献
8.
Object orientation and formal methods are widely regarded as two fields with significant potential for new software engineering techniques. This paper discusses the relations between these two approaches. We present various specification techniques which incorporate object-oriented paradigms, discuss their place in software development process, and analyse possible benefits from their applications. 相似文献
9.
AK Ma?ek O Rowiński T Ostrowski L Hilgertner M Januszewicz M Szostek 《Canadian Metallurgical Quarterly》1995,50(40-44):19-22
Subclavian steal syndrome (SSS) appears when the origin of the subclavian artery (SA) is occluded or stenosed. Introduction of transcranial Doppler sonography (TCD) provided an opportunity to evaluate parameters of the blood flow in the vertebral (VA) and basilar artery (BA). Measurements of blood flow velocities performed at rest and after the brachial hyperemia test allow one to classify hemodynamic types of SSS. The aim of the study was to categorize types of steal and to compare the differences of flow patterns before and after percutaneous transluminal SA balloon angioplasty (SA-PTA). Fourty-eight patients with angiographically confirmed SSS (aged from 27 to 68 years, mean 53; 2/1 f/m ratio) were examined with 2 MHz range-gated, pulsed transcranial Doppler device (TC 2-64B EME). Both VA and BA were evaluated by the transoccipital approach at rest and during the brachial hyperemia. In 5 cases (10.4%) permanent reversal blood flow in the BA was observed (complete basilar steal). In flow in the BA blood flow was in the normal direction at rest and altered (reversed or decreased) when induced with brachial hyperemia test (transient basilar steal). In the next 14 patients (29.2%) permanently reversed VA blood flow was observed with only a slight or no alterations of the BA flow after the hyperemia test (complete vertebral steal). In the last 19 cases (39.6%) alterations of the VA blood flow without changes in BA flow were observed (latent vertebral steal). Between 1991 and 1994 twenty seven symptomatic patients with different hemodynamic types of SSS were treated with SA-PTA. TCD evaluation of VA's and BA using the hyperemia test was performed before, 3 to 7 days and 3 months after morphologically and hemodynamically successful subclavian artery balloon PTA. Normal results of vertebrobasilar examinations were obtained in 26 cases after this procedure. In one case the latent vertebral steal was detected. The 28 months mean follow-up revealed no significant changes in TCD flow patterns recorded from VA's and BA. After collecting data of about 60 patients with SSS we examined with TCD we conclude that: in patients with a hemodynamically significant SA stenosis the presence of reversed ipsilateral VA blood flow (a radiologic steal) its not a good determinant of either the presence or type of presenting symptoms and after successful PTA or recanalisation and PTA of SA in almost all cases we examined close to normal TCD recordings in BA and VA. 相似文献
10.
Keith S. Matlack Tomasz Labuda 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》1995,62(1):91-93
A method for analyzing the fluorine content of glass using a microwave oven to digest the glass is presented. Analysis time and secondary waste generation are reduced using this method, without sacrificing accuracy. 相似文献