Photodynamic treatment (ALA-PDT) suppresses the expression of the oncogenic Bcr-Abl kinase and affects the cytoskeleton organization in K562 cells

K562 is the chronic myelogenous leukemia (CML)-derived cell line that expresses high levels of chimeric oncoprotein Bcr-Abl. The deregulated (permanent) kinase activity of Bcr-Abl leads to continuous proliferation of K562 cells and their resistance to the apoptosis promotion by conventional drugs. The photodynamic treatment (PDT) based on the application of 5-aminolevulinic acid (ALA) and irradiation with blue light (ALA-PDT) resulted in the suppression of K562 cells proliferation. It was followed by a necrosis-like cell death [K. Kuzelová, D. Grebenová, M. Pluskalová, I. Marinov, Z. Hrkal, J. Photochem. Photobiol. B 73 (2004) 67-78]. ALA-PDT led to the perturbation of the Hsp90/p23 multichaperone complex of which the Bcr-Abl is the client protein. Bcr-Abl protein was suppressed whereas the bcr-abl mRNA level was not affected. Further on, we observed several changes in the cytoskeleton organization. We detected ALA-PDT-mediated disruption of filamental actin structure using FITC-Phalloidin staining. In connection with this we uncovered certain cytoskeleton organizing proteins involved in the cell response to the treatment. Among these proteins, Septin2, which plays a role in maintaining actin bundles, was suppressed. Another one, PDZ-LIM domain protein 1 (CLP36) was altered. This protein acts as an adaptor molecule for LIM-kinase which phosphorylates and thus inactivates cofilin. Cofilin was indeed dephosphorylated and could thus be activated and operate as an actin-depolymerizing factor. We propose the scheme of molecular response of K562 cells to ALA-PDT.     

Screening for drugs in serum by electrospray ionization/collision-induced dissociation and library searching

Factors influencing in-source collision-induced dissociation (ESI/CID) of organic molecules in a Perkin-Elmer/SCIEX ionspray source have been investigated. Breakdown curves of four drugs and organic compounds were acquired by monitoring the intensities of MH+ and specific fragment ions while ramping the orifice voltage. Haloperidol, diazepam, 1,4-acetamido-acetoxybenzene and diacetamido-1,2-benzene were found to be substances with characteristic breakdown curves, with maximums and points of intersection at orifice voltages between 20 and 70 V. The breakdown curves of haloperidol were used for comparison of ESI/CID with ionspray and turboionspray sources on three PE/SCIEX-API instruments. Using standardized source parameters and mass resolution, very similar fragmentation graphs were obtained for haloperidol with all instruments. Infusion of varying concentrations of haloperidol (0.1 to 10 micrograms/mL with ionspray, and 0.01 to 1 microgram/mL with turboionspray) yielded comparable breakdown curves. With turboionspray, a preconcentration of the aerosol occurred, yielding higher ion abundances. Solvent pH and the ratio of aqueous ammonium formate/acetonitrile had minor effects on the degree of fragmentation of haloperidol in a wide range. With these preconditions, a currently expanding mass spectral library of 400 drugs was set up by liquid chromatography/mass spectrometry with alternating orifice voltages (20, 50, and 80 V, respectively) in a looped experiment. An example of drug identification in a patient's serum with library search is shown.     

Dendritic Metalloporphyrin-Fullerene Conjugates: Changing the Microenvironment around Redox-Active Centers and its Impact on Charge-Transfer Reactions

Photophysical investigations on a series of (2,4,6)-tris-substituted metalloporphyrin-fullerene conjugates revealed the effects of an electron-rich microenvironment surrounding the electron-donating porphyrin as a function of the metal center. On one hand, for all conjugates-water-soluble and non-water-soluble-ultrafast charge separation was observed upon photoexcitation. On the other hand, when examining the charge recombination dynamics for the non-water-soluble conjugates it becomes obvious that the (2,4,6)-tris-substitution stabilizes the radical-ion-pair state relative to the mono-substitution in the ortho-, meta-, and para-position. The more efficient protection of the electron-donating porphyrin from solvation is thought to be the major cause for this impact. Nevertheless, the situation is slightly different for the water-soluble conjugates. At first glance, the radical-ion-pair state lifetimes are, also in the case of the (2,4,6)-tris-substitution, longer than for the mono-substituted ortho-, meta- and para-conjugates. Upon closer inspection, they fail, however, to exhibit any metal dependence. Competing with the protection from solvation of the dendrons, dipole-charge interactions impact the stabilization in the polar aqueous environment and, in turn, become the dominant force governing the electron-transfer dynamics.     

Settings and methods for global sensitivity analysis – a short guide

Global sensitivity analysis offers a set of tools tailored to the impact assessment of certain assumptions on a models output. A recent book on the topic covers those issues [1]. Given the limited space for discussing thoroughly any of those methods, we will next summarize the main conclusions that derive from the application of various global sensitivity analysis methods on chemical models [2], econometric studies [3] financial models [4] and composite indicators [5, 6]. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)     

Elliptic Equations with Degenerate Coercivity： Gradient Regularity

In this paper, we prove higher integrability results for the gradient of the solutions of some elliptic equations with degenerate coercivity whose prototype is where for example, a(x,u)=(1+|u|)^−θ with θ ∈ (0,1). We study the same problem for minima of functionals closely related to the previous equation.     

Competence-driven project portfolio selection,scheduling and staff assignment

This paper presents a new model for project portfolio selection, paying specific attention to competence development. The model seeks to maximize a weighted average of economic gains from projects and strategic gains from the increment of desirable competencies. As a sub-problem, scheduling and staff assignment for a candidate set of selected projects must also be optimized. We provide a nonlinear mixed-integer program formulation for the overall problem, and then propose heuristic solution techniques composed of (1) a greedy heuristic for the scheduling and staff assignment part, and (2) two (alternative) metaheuristics for the project selection part. The paper outlines experimental results on a real-world application provided by the E-Commerce Competence Center Austria and, for a slightly simplified instance, presents comparisons with the exact solution computed by CPLEX.