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Biomedical subjects

F Devínsky

Publications and source records attributed to F Devínsky.

At least 37 records · Page 2Linked to original sources
PubMed1993

Primary biodegradation of amine oxide and quaternary ammonium amphiphiles.

Biodegradation of two amphiphilic "soft" antimicrobially active derivatives of lauric (dodecanoic) acid, a quaternary ammonium salt and an amine oxide bearing an amide or ester group, was followed using microorganisms from activated sludge. Primary biodegradation was determined by ion-selective electrodes, total biodegradation as the chemical oxygen demand. Though organic ammonium salts quickly undergo primary biodegradation, the rest of the molecule is difficult to destroy. In contrast, amine oxides are easily biodegradable.

Amines↗
PubMed1993

Amphiphilic detergents inhibit production of IgG and IgM by human peripheral blood mononuclear cells.

All types (cationic, anionic and non-ionic) amphiphilic detergents significantly inhibited the production of both IgG and IgM by human peripheral blood mononuclear cells after polyclonal activation in vitro. The most potent inhibitors were didodecyldimethylammonium bromide (DDAB) and (1-methyldodecyl)dimethylamine N-oxide (2-ATDNO). They were able to suppress effectively the immunoglobulin production in 10(-3)-10(-8) M concentrations. A medium inhibitory effect was observed with Slovapon, sodium dodecyl sulphate (SDS) and Triton X-100, while Slovanik showed an inhibition only in concentrations higher than 10(-2)%. These results suggest that amphiphilic detergents may be characterized as potential immunotoxic substances with very negative effects on the immunoglobulin production.

Detergents↗
PubMed1993

Effect of 1-alkylpyrrolidine N-oxides on energy metabolism of cancer cells.

The main purpose of the present investigation was to study the effect of a homologous series of 1-alkylpyrrolidine N-oxides on ATP-producing processes in Ehrlich ascites and L1210 murine leukemia cells. The effect on aerobic glucose consumption, lactic acid formation, content of total (T-SH) and non-protein thiol groups (NP-SH), endogenous respiration and the level of ATP in tumor cells incubated in vitro was investigated. 1-Tetradecylpyrrolidine N-oxide (TPNO), one of the most active compounds, immediately after addition to the suspension of Ehrlich cells in an ice bath, decreased the level of ATP to the same extent over the whole concentration range. After 2 h incubation at 37 degrees C the drop in the ATP level was lower. The decrease in ATP level might be explained through the interaction of the amine oxide with the cell membrane integrity.

Adenosine Triphosphate↗
PubMed1992

Potassium leakage from Escherichia coli cells treated by organic ammonium salts.

The effect of the homologous series of 1,1-dialkylpiperidinium bromides on the potassium leakage from Escherichia coli cells has been studied. The minimum concentration for each compound which is able to release maximum of cellular potassium has been determined and correlated with the inhibitory activities of the compounds. The relationship between the structure and the activity enables to consider the K+ leakage as the marker of inhibitory activity of the membrane active antimicrobials.

Cell Membrane Permeability↗
PubMed1992

Enhanced biodegradation of a hard bis-quaternary ammonium salt.

Bacterial strains with a high biodegradation potential were isolated from activated sludge. Their ability to decompose the hard bis-quaternary ammonium salt FB was determined by the method of chemical oxygen demand (COD) in a mineral medium, where the compound FB was the only source of carbon. The COD values were very low after 21 d and in the course of this period they reached zero level twice. The contribution of adsorption to decrease the COD value was small. The maximum COD decrease was accompanied by an increase of cell respiration. It is suggested that FB is effectively decomposed in spite of the fact that according to its structure it is a typical hard detergent.

Bacteria↗
PubMed1992

Biochemical basis of cytotoxic activity of some new N'-oxides of N',N'-dimethylaminoalkylamides of dodecanoic acid.

The objective of the present investigation was to screen a series of new N'-oxides of N',N'-dimethylaminoalkylamides of dodecanoic acid for activity in vitro and to investigate the biochemical mode of action. On the basis of primary screening, one of the most active compounds, namely the N'-oxide of 10-(N',N'-dimethylaminodecyl)amide of dodecanoic acid (n = 10) was chosen for detailed biochemical study. This compound inhibited the incorporation of 14C-precursors (adenine, valine, thymidine, uridine) into appropriate macromolecules of P388 murine leukemia and Ehrlich ascites carcinoma cells. The amine oxide also interfered with energy-yielding processes (aerobic glycolysis, endogenous respiration). Cytotoxicity is a consequence of the cytolytic activity of the compounds mentioned above. Membranous effects were demonstrated by the measuring of the release of cytoplasmic materials absorbing at 260 and 280 nm, marker enzyme activities (LDH, MDH), release of protein from the cells into the culture medium, as well as by morphological examination. It is evident that the site of action of the amine oxides investigated was the biological membrane which, after interaction with the amine oxides, showed changes in molecular organization and osmotic and permeability characteristics.

Animals↗
PubMed1992

[Immunochemical changes in the outer membrane of Escherichia coli adapted to amine oxides].

Resistant strains of Escherichia coli were obtained by stepwise cultivation in subinhibitory concentrations of two antimicrobially active amine oxides. Changes in the chemical composition of the outer membrane of the resistant strains were accompanied also by different antigenic reactions. New precipitation lines were revealed by double immunodiffusion and immuno-electrophoretic methods. The results of immunochemical analysis confirm the findings that the resistance to amphiphilic compounds is associated with the outer membrane which limits the access of antimicrobially active molecules to their sites of action in the cytoplasmic membrane.

Antigens, Bacterial↗
PubMed1991

Relationships between the chemical structure and cytotoxicity of 4-alkylmorpholine N-oxides.

The main objective of the present investigation was to screen a series of 4-alkylmorpholine N-oxides for in vitro cytotoxicity and to find out whether there is a quantitative structure-activity correlation (QSAR) between cytotoxic effect represented here by inhibition of incorporation of [14C]adenine into nucleic acid or [14C]valine into proteins in Ehrlich ascites carcinoma (EAC) cells and structure (as a structural parameter the number of carbon atoms m in the alkyl chain was used). On the basis of primary screening, one of the most active compounds, namely 4-dodecylmorpholine N-oxide, was chosen for further biochemical study. The drug inhibited the incorporation rate of [14C] precursors (adenine, thymidine, uridine, valine) into appropriate macromolecules of Ehrlich cells, the extent of inhibition being dependent on both time and concentration of the compound in the incubation medium. The lengthening of the alkyl chain in 4-alkyl-morpholine N-oxides positively affected their cytotoxic activity in Ehrlich cells. For these compounds the optimal m-value is 15-16.

Animals↗
PubMed1991

[Organic ammonium salts. XLI. Preparation, aggregation properties and antimicrobial activity of N-[2-(10-undecenoyloxy)ethyl]-N,N,N-alkyldimethylammonium bromides].

The paper describes the preparation of 7 novel organic ammonium salts of N-[2-(10-undecenoyloxy)ethyl]-N,N,N-alkyl-dimethylammonium bromides, in which the alkyl chain was gradually lengthened from ethyl to tetradecyl, constantly keeping the other groups (10-undecenoyloxyethyl and methyl) bound to the ammonium nitrogen. In the paper the antimicrobial effect of the prepared ammonium salts and the aggregative properties of their aqueous solutions were studied. The aggregative properties are expressed by the values of the critical concentration of the micelles formation, which were determined tensiometrically and conductometrically. The antimicrobial activity expressed by the minimal inhibition concentration in dependence on the prolongation of the alkyl chain was determined by the dilution test on the strains Staphylococcus aureus, Escherichia coli and Candida albicans. As follows from the table, all ammonium salts prepared were active in this respect, the most effective ones possessing 6, 8 and 10 carbon atoms in the alkyl chain. They were more effective than the standard Ajatin to all strains of the microorganisms tested. The antimicrobial effect decreased with the increasing length of the alkyl chain. Also the structure--activity relationship was quantified by the QSAR analysis methods using two procedures: the dependence log ck vs. m was linear and the dependence log (1/MIC) vs. m and log (1/MIC) vs. log ck were nonlinear. The calculated coefficients of regression equations and statistical evaluation of dependences are shown in Table 4.(ABSTRACT TRUNCATED AT 250 WORDS)

Candida albicans↗
PubMed1990

Interaction of surfactants with model and biological membranes. II. Effect of N-alkyl-N,N,N-trimethylammonium ions on phosphatidylcholine bilayers as studied by spin probe ESR.

The interaction of N-alkyl-N,N,N-trimethylammonium (CnTMA, n = 6-18) salts (iodides and/or bromides) with model membranes prepared by hydration of egg yolk phosphatidylcholine (EYPC) over aqueous salt solutions has been studied by m-doxyl stearic acid (m-DSA, m = 12 and 16) spin probe method. In disoriented EYPC bilayers the CnTMA salts decrease the orientational order parameter S33 of m-DSA evaluated from the powder pattern ESR spectra. This effect is maximal for C6TMA. In oriented EYPC bilayers prepared by the parallel-beam sputtering method and hydrated over saturated NaCl solution the order parameter S33 calculated from the angular dependence of the nitrogen hyperfine splitting is decreased in the presence of C6TMA. The order parameter S11 obtained from the angular dependence of line positions indicates deviation of m-DSA motion from axial symmetry. C6TMA increases the probability of gauche conformations of the lipid chains by about 13-14%, and decreases the effective energy difference between the trans and gauche conformations by about 420-480 J/mol, at molar ratio of EYPC/C6TMA = 2:1. The angular dependence of linewidths is analysed by employing a theory of spin relaxation based on the strong collision model for molecular reorientations. The correlation time tau 0 of the reorientation of an axis orthogonal to the doxyl ring of 16-DSA is decreased in the presence of C6TMA, while that of 12-DSA is not influenced by it. The ratio of tau 2/tau 0 is increased in the presence of C6TMA for the both spin probes. The results are explained using the free-volume model of the CnTMA-EYPC membrane interaction.

Electron Spin Resonance Spectroscopy↗
PubMed1990

Cut-off effect in antimicrobial activity and in membrane perturbation efficiency of the homologous series of N,N-dimethylalkylamine oxides.

The antimicrobial activity of the homologous series of N,N-dimethylalkylamine oxides (DMAO) was found to be quasi parabolically dependent on alkyl chain length with a maximum at n approximately 15 and n approximately 12 for Staphylococcus aureus and Escherichia coli, respectively. The physiochemical properties of DMAOs as characterized by critical micelle concentrations, retention times of 1-alkenes generated from DMAOs by gas-liquid chromatography, Rm values in reversed phase chromatography, and bacterial lipid/aqueous phase partition coefficients were found to correlate with the alkyl chain length. The effect of DMAOs on the structure of the model membrane prepared from isolated lipids from Escherichia coli as detected by a spin probe method was maximal for the alkyl chain length n approximately 10-12 coinciding with the maximum in the antimicrobial activity observed with Escherichia coli. It is suggested that the cut-off in the DMAO antimicrobial activity is caused by the cut-off in the DMAO perturbing effect on the membrane structure.

Anti-Bacterial Agents↗
PubMed1990

Electron spin resonance study of chloroplast photosynthetic activity in the presence of amphiphilic amines.

Electron spin resonance spectroscopy (ESR) was used to study the effects of amphiphilic amines of the carbamate, amide, and ester type and amine oxide on the photosynthetic system of spinach chloroplasts. The ESR signal II connected to the photosynthetic center PS II donor side was observed to diminish in the presence of amines, whereas that of PS I remained unchanged. The inhibition of PS II increased with the increasing of amine concentration. In the presence of amines, the light: dark chloroplast ESR signals ratio as well as the intensity of the ESR signal of unbound Mn2+ increased. It is suggested that the amphiphilic amines affect the structure of PS II and the electron transfer to PS I. The effects of the amines tested on the photosynthetic system correlate with their potency to perturb the lipid membrane structure.

Amines↗
PubMed1989

Pyrolysis gas-liquid chromatography of N,N-dimethylalkylamine N-oxides and their mixtures.

A rapid quantitative and small scale method based on direct injection pyrolysis gas-liquid chromatography is described for the determination of N,N-dimethylalkylamine N-oxides. The method is suitable for determination of individual N-oxides as well as of their homologous compositions with or without the presence of parent tertiary amines in water or methanol solutions. The sensitivity of the method is 10-15 nmol of compounds injected. The unsymmetrical (1-methyldodecyl)dimethylamine N-oxide forms two isomeric alkenes 1-tridecene and trans-2-tridecene in a ratio of 1.68, in agreement with the predicted value.

Chromatography, Gas↗
PubMed1989

Effect of N,N'-bis(alkyldimethyl)-alpha, omega-alkanediammonium dibromides on bacteria of the genus Clostridium.

Antibacterial effect of 17 ammonium compounds of the type of N,N'-bis(alkyldimethyl)-alpha, omega-alkanediammonium dibromides was tested on anaerobically sporulating bacteria of the genus Clostridium. A sizable antibacterial activity was displayed by five N,N'-bis(alkyldimethyl)-1,6-hexanediammonium dibromides and by four N,N'-bis(decyldimethyl)-alpha, omega-alkanediammonium dibromides. These compounds exhibited activity higher than, or comparable with, that of the reference standards Ajatin and Septonex. The maximum antibacterial activity was found in compounds whose alkyl chain contained 9-12 carbon atoms. Compounds with a lower number of carbon atoms in the chain (less than 8) exhibited a low activity.

Benzalkonium Compounds↗