Abstract— We have compared the cytotoxicity of daunomycin in vitro to highly differentiated normal epithelial cells (Fisher rat thyroid cells, FRTL-5) and to two neoplastic cell lines, a thyroid carcinoma (TK-6) and its lung metastasis (MPTK-6). Whereas the cell lines are equally sensitive to the drug in the dark, if irradiated during incubation with daunomycin (86 J/cm2 at 488 nm), they become more and differently sensitive. Namely, the drug doses producing 50% mortality decrease by factors of about 22, 28 and 16 for FRTL-5, TK-6 and MPTK-6 cell lines, respectively. This result correlates with differences in drug uptake and resistance observed in the normal and neoplastic cell lines. 相似文献
Wool fibres were modified by treatment with tannic acid (TA) solution or by acylation with ethylenediaminetetraacetic (EDTA) dianhydride. The unmodified and modified fibres were subsequently treated with Cu2+ and Co2+ solutions, at alkaline pH, and analysed by Attenuated Total Reflectance, ATR/IR spectroscopy to evaluate the changes induced in the structure of the fibre by metal binding. The spectral changes were correlated to metal adsorption results obtained by Inductive Coupled Plasma-Atomic Emission Spectrometry (ICP-AES).
The IR results were discussed in relation to our previous findings on the metal binding mode of Bombyx mori and Tussah silk fibres; the changes observed in the spectra were explained by considering the different affinity of the fibres for the modifying reagent and the amount of the metal absorbed. More relevant spectral changes were observed upon Cu2+ complexation rather than Co2+ complexation, according to the metal absorption results. The most relevant changes were observed for the EDTA-modified wool sample treated with Cu2+, according to the higher affinity of wool for EDTA. The IR spectra were quantitatively evaluated by the intensity ratio between the Amide I and Amide II bands (IAmideI/IAmideII) and its trend as a function of metal absorption was reported.
The present investigation demonstrated that the interaction between fibre and metal and the subsequent fibre modification depend on the chemical nature of the fibre, the metal cation and the modifying reagent. 相似文献
This work presents an all-electron density functional theory implementation of the separation of sigma and pi energies. On the basis of the separation of the electronic density, rho, into sigma and pi parts, an ansatz for the separation of the exchange-correlation energy is proposed. The behavior of the sigma and pi energy parts in benzene is investigated under different distortions. The effect of local and nonlocal functionals on the separation of the exchange-correlation energy is studied, too. 相似文献
A detailed analysis of toxic shellfish collected in the Adriatic sea in October 2000 allowed us to isolate a new cytotoxic chlorosulfolipid (3). Its gross structure has been elucidated through an extensive NMR analysis including various 2D techniques; the relative stereochemistry has been solved by applying the Murata's method. Compound 3 showed to posses cytotoxic activity against WEHI 164 and J774 cells. The presence of chlorosulfolipids in toxic mussels from the northern Adriatic sea has not to be considered incidental as we have been detecting these cytotoxic compounds since 1998. Their simultaneous and constant presence together with typical marine biotoxins represents a further risk both to consumers' health and aquacultures economic proceeds. 相似文献
Dysferlin is a plasma membrane protein of skeletal muscle whose deficiency causes Miyoshi myopathy, limb girdle muscular dystrophy 2B and distal anterior compartment myopathy. Recent studies have reported that dysferlin is implicated in membrane repair mechanism and coimmunoprecipitates with caveolin 3 in human skeletal muscle. Caveolin 3 is a principal structural protein of caveolae membrane domains in striated muscle cells and cardiac myocytes. Mutations of caveolin 3 gene (CAV3) cause different diseases and where caveolin 3 expression is defective, dysferlin localization is abnormal. We describe the alteration of dysferlin expression and localization in skeletal muscle from a patient with raised serum creatine kinase (hyperCKaemia), whose reduction of caveolin 3 is caused by a CAV3 P28L mutation. Moreover, we performed a study on dysferlin interaction with caveolin 3 in C2C12 cells. We show the association of dysferlin to cellular membrane of C2C12 myotubes and the low affinity link between dysferlin and caveolin 3 by immunoprecipitation techniques. We also reproduced caveolinopathy conditions in C2C12 cells by a selective p38 MAP kinase inhibition with SB203580, which blocks the expression of caveolin 3. In this model, myoblasts do not fuse into myotubes and we found that dysferlin expression is reduced. These results underline the importance of dysferlin-caveolin 3 relationship for skeletal muscle integrity and propose a cellular model to clarify the dysferlin alteration mechanisms in caveolinopathies. 相似文献
The oxidation of benzyl alcohols with the enzyme laccase, under mediation by appropriate mediator compounds, yields carbonylic products, whereas laccase can not oxidise these non-phenolic substrates directly. The oxidation step is performed by the oxidised form of the mediator (Med(ox)), generated on its interaction with laccase. The Med(ox) can follow either an electron transfer (ET) or a radical hydrogen atom transfer (HAT) route of oxidation of the substrates. Experimental evidence is reported that enables unambiguous assessment of the occurrence of either one the oxidation routes with each of the investigated mediators, namely, ABTS, HBT, HPI and VLA. Support to the conclusions is provided by (i) investigating the intermolecular selectivity of oxidation with appropriate substrates, (ii) attempting Hammett correlations for the oxidation of a series of 4-X-substituted benzyl alcohols, (iii) measuring the kinetic isotope effect, (iv) investigating the product pattern with suitable probe precursors. Based on these points, a HAT mechanism results to be followed by the laccase-HBT, laccase-HPI and laccase-VLA systems, whereas an ET route appears feasible in the case of the laccase-ABTS system. 相似文献