[Methods for studying tumor cell migration and invasiveness]. / Metody studia bunecné migrace a invazivity nádorových bunek.

Migration and invasiveness are phenotypic characteristics of cells that contribute to physiological processes, such as wound healing or embryogenesis and they are involved in serious pathological processes, namely in tumor cell metastasis. Availability of methods for studying migration and invasiveness of the cells is important for understanding molecular basis of these processes. In the case of cancer, migration, invasiveness and metastatic potential of tumor cells are key factors that determine clinical prognosis of the patients. This communication provides an overview of in vitro and in vivo methods which are used to study cell migration, invasion and metastasis. In vitro meth-ods for studying cell migration include simple two dimensional assays (scratch -  wound assay and the assay based on the effect of hepatocyte growth factor) and methods based on chemotaxis (Dunns chamber, videomicroscopy of cells, the use of carriers with chemoattractants). Methods for studying both cell migration and invasiveness in vitro include more complex systems based on the principle of the Boyden chamber (transwell migration/ invasive test, analysis of cell migration and invasion in xCELLigence system, confocal microscopy based approaches) as well as analysis of cell migration in microchannels. Our overview of in vivo methods provides an introduction into model organisms and methods used in this field, with an emphasis on the study of cancer metastasis in mouse models. The methods described in this review are mainly involved in larger research projects aiming at developing new diagnostic and therapeutic approaches in oncology.

The retention behaviour of polar compounds on zirconia based stationary phases under hydrophilic interaction liquid chromatography conditions.

The most separations in HILIC mode are performed on silica-based supports. Nevertheless, recently published results have indicated that the metal oxides stationary phases also possess the ability to interact with hydrophilic compounds under HILIC conditions. This paper primarily describes the retention behaviour of model hydrophilic analytes (4-aminobenzene sulfonic acid, 4-aminobenzoic acid, 4-hydroxybenzoic acid, 3,4-diaminobenzoic acid, 3-aminophenol and 3-nitrophenol) on the polybutadine modified zirconia in HILIC. The results were simultaneously compared with a bare zirconia and a silica-based HILIC phase. The mobile phase strength, pH and the column temperature were systematically modified to assess their impact on the retention of model compounds. It was found that the retention of our model hydrophilic analytes on both zirconia phases was mainly governed by adsorption while on the silica-based HILIC phase partitioning was primarily involved. The ability of ligand-exchange interactions of zirconia surface with a carboxylic moiety influenced substantially the response of carboxylic acids on the elevated temperature as well as to the change of the mobile phase pH in contrast to the silica phase. However, no or negligible ligand-exchange interactions were observed for sulfanilic acid. The results of this study clearly demonstrated the ability of modified zirconia phase to retain polar acidic compounds under HILIC conditions, which might substantially enlarge the application area of the zirconia-based stationary phases.

Determination of lipophilicity of novel potential antituberculotic agents using HPLC on monolithic stationary phase and theoretical calculations.

The HPLC analyses on the monolithic stationary phase were employed for rapid determination of lipophilicity of the two sets of newly synthesized potential antituberculotic agents. The analyses utilized the mixture of methanol and phosphate buffer (pH 7.4) as a mobile phase and a flow rate of 4mL/min. Monolithic stationary phase enabled to significantly reduce the time of analyses, achieve appropriate peak shapes for all tested compounds as well as the separation of positional isomers. Furthermore, the theoretical lipophilic parameters (logP) for all compounds were calculated employing the chemical programs (e.g., ACD/logP, HyperChem, miLogP, AlogP, KOWWIN and COSMOFrag, etc.). The experimental data (logk) and calculated logP values were compared by linear regression analysis. The highest correlation for both series was obtained for KOWWIN and miLogP programs. However, capability of particular chemical software to precisely predict lipophilicity of a compound is structurally dependent. Thus the predictive power of the selected program should be verified using experimental method. The results of this study documented that experimental determination of lipophilicity using HPLC on monolithic stationary phase is practical and reasonable for this purpose.

HPLC study on stability of pyridoxal isonicotinoyl hydrazone.

Biocompatible iron chelators are currently under extensive investigation as promising drug candidates. Pyridoxal isonicotinoyl hydrazone (PIH) is a lead compound of the aroylhydrazone group of novel iron chelating agents. In this study, the precise and accurate HPLC analytical methods were used for the stability evaluation of water-soluble PIH salt (PIH x 2HCl) in aqueous media of different pH (2.0, 3.9, 7.0, 9.0 and 12.0) as well as in two selected pharmaceutical co-solvents at both laboratory and elevated (40 degrees C) temperatures. The susceptibility of PIH x 2HCl to oxidative decomposition was studied in the solutions of hydrogen peroxide (3 and 30%). Furthermore, the solid substance of PIH x 2HCl was exposed to UV, dry and wet heat. Our experiments revealed that PIH was considerably sensitive to hydrolytic decomposition in aqueous media, resulting in the splitting of the hydrazone bond. The elevated temperature significantly accelerated the hydrolytic reaction. The lowest rate of hydrolysis of PIH was observed in the phosphate buffer of pH 7.0 and in the pharmaceutical co-solvents (30% PEG-300 and 10% Cremophor EL). No special degradation products were detected in the samples exposed to either hydrogen peroxide or co-solvents. The solid substance of PIH x 2HCl was stable when exposed to UV, dry or wet heat for 33 h.

[Comparison of the therapeutic effectiveness of membrane and centrifugation plasmapheresis]. / Srovnání úcinnosti lécebné membránové a centrifugacní plazmaferézy.

The authors compared 10 pairs of membrane plasmaphereses on an apparatus A 2008 PF and filter Plasmaflux P 2 with 10 centrifugation plasmaphereses on an apparatus Fenwal CS 3000. They evaluated the effectiveness by changes of plasma concentrations of total protein, albumin, beta 2 microglobulin, IgG, IgA, C3 complement, IgM, circulating immune complexes, urea, creatinine, uric acid, cholesterol, triacylglycerols and the clearance of these substances. Changes of plasma concentrations caused by plasmapheresis with the methods used did not differ in any of the investigated substances. The clearance of membrane plasmapheresis was for all substances higher than when the centrifugation method was used. Among values from which the clearance is determined no difference was proved between the two methods in the volume of exchanged plasma, the concentration of the substance in the removed plasma and its mid plasma concentration during the operation. The higher clearance of membrane plasmapheresis was due to the more rapid plasma exchange.

[Plasma proteins and other substances in membrane plasmapheresis. Relation to possibilities and limitations of this therapeutic method]. / Sledování plazmatických bílkovin a dalsích látek pri membránové plazmaferéze. Vztah k moznostem a omezením této lécebné metody.

The authors investigated the effectiveness of therapeutic membrane plasmapheresis and its influence on plasma concentrations of 17 proteins, cholesterol, triacylglycerols, urea, creatinine and uric acid. To this end they made 30 operations on monitors A 2008 PF with filters Plasmaflux P 2, where they exchanged one volume of plasma and replaced it with isooncotic albumin. They assessed the plasma concentrations of the investigated substances before, in the course of and after the operation, estimated sieving coefficients during the 15th and 90th minute and the clearance. Under conditions in vivo they confirmed that the sieving coefficients of the investigated substances approach the value of "1" and the clearance of the filtration rate, i.e. that the investigated substances pass easily through the plasmafilter and that plasmapheresis removes the substances non-selectively. They demonstrated that the assessment of plasma concentrations alone can lead to underestimation of the effectiveness of the operation. Assessment of sieving coefficients and clearance makes more adequate evaluation of the effectiveness of the procedure possible. Assessment of sieving coefficients and clearance made it obvious that plasma concentrations do not depend only on the amount of substance removed by plasmapheresis but also on other factors which must be investigated. The authors' findings support efforts to introduce methods for the selective removal of pathogenetic substances.