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51.
Claire Joqueviel Véronique Gilard Robert Martino Myriam Malet-Martino Ulf Niemeyer 《Cancer chemotherapy and pharmacology》1997,40(5):391-399
Phosphorus-31 nuclear magnetic resonance spectroscopy was used to evaluate the stability of carboxycyclophosphamide (CXCP)
and carboxyifosfamide (CXIF) in human urine at pH 7.0 and 5.5 at 25°, 8°, −20°, and −80 °C. At 25 °C and pH 7.0, CXCP and
CXIF are relatively stable (≈10% degradation in 24 h). In contrast, they are much less stable at pH 5.5 (≈80% degradation
of CXIF and ≈50% degradation of CXCP in 24 h). The rate of degradation of CXCP and CXIF was a function of the storage temperature
of the urine samples but, even at −80 °C, was not negligible: ≈30% degradation for CXCP irrespective of pH and ≈40% and 50%
degradation for CXIF at pH 7.0 and 5.5, respectively, after storage for 6 months. CXCP was more stable than CXIF at either
pH (7.0 or 5.5) and at all storage temperatures (8°, −20°, or −80 °C) of the urine samples. CXCP and CXIF were more stable
at pH 7.0 than at pH 5.5, although this difference fell with decreasing temperatures to be almost negligible at −80 °C. To
ensure a true estimate of CXCP and CXIF levels, urine samples must be frozen and stored at −80 °C within a few hours of micturition.
CXCP and CXIF assays should also be carried out within 2 months and 1 month of storage, respectively.
Received: 13 July 1996 / Accepted: 20 January 1997 相似文献
52.
Antonio Vivi Maria Tassini Hava Ben-Horin Gil Navon Ofer Kaplan 《Breast cancer research and treatment》1997,43(1):15-25
Lonidamine (LND) is a relatively new anti-cancer drug,and several clinical trials have indicated that it may be effectivein combinations with other therapeutic modalities. LND isclassified within the metabolic inhibitor agents. Multidrugresistance (MDR) phenomenon is often associated with increasedenergy requirements, and enhanced glycolysis rate. These studieswere performed to delineate the mechanism of action of LNDon MDR human breast cancer cells, and to investigate whetherLND as a single agent, or in combination with anotheranti-metabolism drug, 2-deoxyglucose (2-DG), may be usefulagainst MDR tumors. The effects of LND on intact perfuseddrug-sensitive (WT) and 33-fold resistant to Adriamycin(Adr) MCF-7 cells, embedded in alginate micro capsules, were continuouslymonitored by 31P and 13C nuclearmagnetic resonance (NMR) spectroscopy. 31PNMR studies showed that LND induced intracellular acidificationand depletion of NTP in both WT and Adr cells. However, pH and NTPlevels decreased less in the Adr cells than in the WT cells(p < 0.05 for both parameters). 13CNMR demonstrated that LND inhibited lactate transport,and lactate signals were elevated in both cell lines. However, theintracellular lactate levels increased to a greater extentin the WT than in the Adr cells (p < 0.05).There were major differences in the effects of LND onmetabolism between sensitive and resistant cells.While LND enhanced glucose uptake in the WT cells, and itsadministration was followed by continuous increase oflactate signal, both processes were not affected by LNDin the Adr cells. 2-DG is a glucose analogue that inhibitsboth cellular uptake and utilization of glucose, leading to cell starvation. Combined treatment with LND and2-DG yielded at best additive, but not synergistic,cellular toxicity, and the metabolic effects of LNDwere attenuated by 2-DG. These results showed that the principalmechanism of action of LND is inhibition of lactate transportleading to intracellular lactate accumulation and acidificationin both WT and Adr cells. The Adr cells were only 2-fold resistantto LND (compared to the WT cells), and since cellular uptakeof alkaloid chemotherapy is improved in acidic environment,LND may have a role in the treatment protocols of MDR tumors,especially when given as the initial means for inductionof intracellular acidification. 相似文献
53.
本文分析了我国永磁MRI发展的历程和目前所面临的挑战;从磁学角度对当前主流永磁MRI磁体的构成方案进行了研究。提出了旨在推动我国永磁MRI产业发展的三点建议:1、开发0.5T级-永磁MRI磁体,把永磁MRI推到中场;2、开发用于手术中的专用永磁MRI;3,探讨将用于NMR测井的“insideout”概念引入血管成像的可能性。文中的叙述贯穿了借永磁MRI工作载体将我国稀土永磁资源从资源优势提升为经济优势的思想。 相似文献
54.
55.
红葱抗稻瘟霉活性成分研究 总被引:4,自引:0,他引:4
目的阐明红葱抗稻瘟霉活性的物质基础.方法利用稻瘟霉筛选体系对红葱的60%(φ)乙醇提取物及其氯仿、正丁醇和水的萃取部分进行活性筛选,并对活性部位的化学成分进行分离鉴定.结果与结论从活性部位中分离得到10个化合物,通过理化性质和波谱数据鉴定它们的结构分别为:异红葱甲素(1)、异红葱乙素(2)、红葱乙素(3)、β-谷甾醇(4)、8-羟基-3,4-二甲氧基-1-甲基-蒽醌-2-羧酸甲酯(5)、4-羟基红葱乙素(6)、hongconin(7)、4,8-二羟基-3-甲氧基-1-甲基-蒽醌-2-羧酸甲酯(8)、dihydro-eleutherinol(9)、1,3,6-三羟基-8-甲基蒽醌(10).其中,9和10为首次从该属植物中分得.化合物2、3、5、6、7、9、10具有较好的诱导稻瘟霉菌丝变形的活性,它们的最小变形浓度(minimummorphologicaldeformationconcentrate,MMDC)分别为30、30、170、130、55、60、150μmol·L-1.用MTT法测定10个化合物的抗肿瘤活性,发现化合物2、3、5、6、7、9有较强的抑制人类红白血病细胞株K562细胞生长的活性,它们的IC50值分别为33、49、266、35、174、154μmol·L-1. 相似文献
56.
Andrea Bernini Ottavia Spiga Arianna Ciutti Maria Scarselli Giuseppe Bottoni Paolo Mascagni Neri Niccolai 《European journal of pharmaceutical sciences》2004,22(5):445-450
A 1H and 13C NMR study on the inclusion complex of paroxetine with β-cyclodextrin was carried out in order to define the stoichiometry of the association and its strength. Proton and carbon chemical shift measurements of paroxetine and β-cyclodextrin were performed at several molar ratios and temperatures, allowing the determination of a 1:1 stoichiometry and an association constant value of the order of 2 × 103 for the paroxetine–β-cyclodextrin complex. Overhauser effects in the rotating frame were also measured, and the experimental interproton distance constraints have been used for molecular model building of the complex. The obtained model indicates that the benzodioxolyl moiety of paroxetine is deeply inserted in the cavity of the cylindrical structure of β-cyclodextrin, while the fluoro-phenyl ring lays above the wider rim. 相似文献
57.
58.
《Pharmaceutical biology》2013,51(8):981-986
AbstractContext: The European white-berry mistletoe [Viscum album L. (Loranthaceae)] is among the oldest known medicinal plants. At present the most important application of mistletoe extracts is in the treatment of cancer. However, natural products specific to mistletoe have rarely been encountered in the current literature.Objective: To discover novel natural products specific to European mistletoe.Materials and methods: European mistletoe was extracted with methanol, purified to partition against diethyl ether and further purified with XAD-7 column chromatography. Pure compounds were separated by Sephadex column chromatography and preparative HPLC. The structures of the novel compounds were established using a combination of several 2D NMR spectroscopic techniques and mass spectrometry.Results: A new type of natural product derived from the methyl ester of γ-hydroxybutyric acid (GHB) coupled to hydroxybenzoic acids, namely 3-(3′-carbomethoxypropyl) gallic acid and 3-(3′-carbomethoxypropyl)-7→3″-protocatechoyl galloate were characterized from European white-berry mistletoe. Condensation of the 3-hydroxyl of gallic acid with the 4-hydroxyl of GHB significantly reduced the radical scavenging properties of the former compound.Discussion and conclusion: The characterized compounds define a novel group of natural products that may be of particular interest because it appears that the two new compounds are not closely related to any known natural product. 相似文献
59.
S. Magnitsky G. K. Belka C. Sterner S. Pickup L. A. Chodosh J. D. Glickson 《NMR in biomedicine》2013,26(1):35-42
This study compared the steady state concentration of lactate in an inducible Her2/nue transgenic breast cancer mouse model and in tumours from the same Her2/neu model grown orthotopically. In vivo lactate was detected by MRS using the Hadamard encoded selective multiple quantum coherence pulse sequence (HadSelMQC) recently developed by our laboratory. A lower lactate signal was observed in the inducible tumours compared to orthotopic tumours in vivo, while ex vivo analysis of perchloric acid extracts revealed similar amounts of this metabolite in both models. Histological staining of mammary tumour specimens showed a much higher level of fat tissue in inducible tumours compared to the orthotopic model. Phantom studies with [3‐13C] lactate indicated that a lipid environment could significantly reduce the T2 of lactate and impede its detection. The transgenic inducible model for breast cancer not only better recapitulated the biological aspects of the human disease but also provided additional characteristics related to in vivo detection of lactate that are not available in orthotopic or xenograft models. This study suggests that the level of lactate measured by the HadSelMQC pulse sequence may be underestimated in human patients in the presence of high lipid levels that are typically encountered in the breast. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献
60.
Jonathan J. Morgan Gale A. Kleven Christina D. Tulbert John Olson April E. Ronca 《NMR in biomedicine》2013,26(6):683-691
This study represents the first longitudinal, within‐subject 1H MRS investigation of the developing rat brain spanning infancy, adolescence and early adulthood. We obtained neurometabolite profiles from a voxel located in a central location of the forebrain, centered on the striatum, with smaller contributions for the cortex, thalamus and hypothalamus, on postnatal days 7, 35 and 60. Water‐scaled metabolite signals were corrected for T1 effects and quantified using the automated processing software LCModel, yielding molal concentrations. Our findings indicate age‐related concentration changes in N‐acetylaspartate + N‐acetylaspartylglutamate, myo‐inositol, glutamate + glutamine, taurine, creatine + phosphocreatine and glycerophosphocholine + phosphocholine. Using a repeated measures design and analysis, we identified significant neurodevelopment changes across all three developmental ages and identified adolescence as a distinctive phase in normative neurometabolic brain development. Between postnatal days 35 and 60, changes were observed in the concentrations of N‐acetylaspartate + N‐acetylaspartylglutamate, glutamate + glutamine and glycerophosphocholine + phosphocholine. Our data replicate past studies of early neurometabolite development and, for the first time, link maturational profiles in the same subjects across infancy, adolescence and adulthood. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献