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Biomedical subjects

I Vincze

Publications and source records attributed to I Vincze.

At least 37 records · Page 2Linked to original sources
PubMed1991

High-performance liquid chromatographic determination of cortolic and cortolonic acids as pyrenyl ester derivatives.

A new procedure is described for the detection of the acidic metabolites of cortisol (cortoic acids) as the pyrenylmethyl-21-oic esters. The derivatizing reagent, diazomethylpyrene, was prepared by an improved procedure. The reagent was used at room temperature, required no catalyst, and was not restricted by stoichiometric requirements. The steroid esters were separated by reversed-phase high-performance liquid chromatography and analyzed simultaneously by their ultraviolet absorbance and fluorescence characteristics. Identities of the products were confirmed using the photodiode array detector to determine spectral profiles, absorbance maxima, and absorbance ratios. Further confirmation of identity of the cortoic acid esters used mass spectrometry under normal and collision-activated dissociation conditions. With the method described, a linear spectral response was obtained between 8 and 1680 fmol. Application of the technique to the analysis of steroid acids in human urine indicated the presence of cortoic acids.

Chromatography, High Pressure Liquid↗
PubMed1991

32P-postlabelling detection of aromatic DNA adducts in peripheral blood lymphocytes from aluminium production plant workers.

Aluminium production plant workers are exposed to a great number of airborne polycyclic aromatic hydrocarbons and epidemiological studies suggest that these workers are at increased risk of lung and bladder cancer. Blood samples from 46 workers at 2 primary aluminium plants and from 29 occupationally unexposed control individuals were analysed. DNA was isolated from the peripheral blood lymphocytes and aromatic DNA adducts were detected by 32P-postlabelling assay using the nuclease P1 digestion procedure for the enrichment of the adducts. The total levels of DNA adducts of exposed individuals varied from the detection limit of about 0.5 adducts/10(8) nucleotides up to 7.1 adducts/10(8) nucleotides and control adduct levels were up to 2.42 adducts/10(8) nucleotides. There was no significant difference between the mean adduct levels of the control group and of the individuals of one plant. However, the mean DNA adduct level obtained from workers of the second plant was significantly higher than that of the controls (p less than 0.001) and of the first plant (p less than 0.01), respectively. This difference can be attributed to differences in the design of technology and different levels of exposure at the 2 plants. The results of this study encourage further investigations of the use of peripheral white blood cells as marker cells and of 32P-postlabelling analysis for monitoring occupational exposure to mixtures of environmental carcinogenic pollutants.

Adult↗
PubMed1990

Influence of cigarette smoking on the levels of DNA adducts in human bronchial epithelium and white blood cells.

The presence of carcinogen-DNA adducts in human tissues is evidence of exposure to carcinogens and may be an indicator of cancer risk. DNA was isolated from non-tumorous bronchial tissue of 37 cigarette smokers, 8 former smokers and 8 non-smokers and analyzed for the presence of aromatic and/or hydrophobic DNA adducts in the 32P-post-labelling assay. Adducts were detected as bands of radioactive material when 5'-32P-labelled deoxyribonucleoside 3',5'-bisphosphates were chromatographed on polyethyleneimine-cellulose tlc plates, and the patterns indicated the formation of adducts by a large number of compounds. Adduct levels detected in DNA from non-smokers, former smokers and current smokers were 3.45 +/- 1.62, 3.93 +/- 1.92 and 5.53 +/- 2.13 adducts/10(8) nucleotides, respectively. The differences in adduct levels between smokers and former and non-smokers were statistically significant (p less than 0.01); and among the smokers, significant correlations were found between adduct levels and both daily cigarette consumption and total cigarette consumption (daily consumption X number of years smoked). DNA was also isolated from the peripheral-blood leukocytes of 31 heavy smokers (greater than 20 cigarettes/day) and 20 non-smokers and analyzed by 32P-post-labelling. Adduct levels in the smokers' samples were not significantly different from levels in the non-smokers' samples (2.53 +/- 1.31 and 2.12 +/- 1.44 adducts/10(8) nucleotides, respectively). Thus, evidence for carcinogen exposure was found in human bronchial epithelium, a target tissue for tobacco-induced tumour formation, but not in peripheral-blood cells, indicating possible limitations in the use of the latter as a surrogate, non-target tissue source of DNA for monitoring human exposure to inhaled carcinogens.

Adult↗
PubMed1990

Dose-related induction of rat hepatic drug-metabolizing enzymes by diuron and chlorotoluron, two substituted phenylurea herbicides.

Dose-related induction of various hepatic drug-metabolizing enzymes has been investigated after short-term treatment of rats by diuron and chlorotoluron, a dichlorinated and a monochlorinated phenylurea herbicide, respectively. Results suggest that 'saturation' of the induction system of benzo(a)pyrene monooxygenase, 7-ethoxycoumarin O-deethylase and 7-ethoxyresorufin O-deethylase activities may occur in the same range of the molar doses of both compounds, and with the dichlorinated herbicide at much higher activities. Induction of epoxide hydrolase, UDP-glucuronyltransferase and glutathione S-transferases also shows saturation curves in the function of molar doses. However, the structural difference is not reflected in the enhancement of enzyme activities.

7-Alkoxycoumarin O-Dealkylase↗
PubMed1989

32P-postlabelling analysis of DNA adducts of benzo[a]pyrene formed in complex metabolic activation systems in vitro.

The influence of cytochrome P-450-linked monooxygenase, epoxide hydrolase, UDP-glucuronyltransferase and glutathione S-transferases on the metabolic activation of benzo[a]pyrene (BP) was studied by incubating BP with preparations of rat-liver microsomal and cytosolic fractions in the presence of exogenous DNA. 32P-Postlabelling analysis of the DNA revealed the presence of covalently bound adducts formed by BP, which were visualised as radioactive spots on autoradiographs of thin-layer chromatograms. The effects on the adduct profile of adding different combinations of 1,2-epoxy-3,3,3-trichloropropane (TCPO), UDP-glucoronic acid (UDPGA) and glutathione (GSH) to the incubation mixture were determined. As many as 14 different DNA adducts were resolved and quantitated on the chromatograms, the numbers and quantities of which varied within a large range depending on the incubation conditions. The influence of the enzyme inhibitor and cofactors on the adduct patterns reflects the complex effects of simultaneous enzyme interactions on the metabolic activation of BP.

Animals↗
PubMed1987

Virulence factors of Escherichia coli. IV. Association in Escherichia coli of LD50 with haemolysin production, haemagglutinating capacity, antigens K1, K5 colicinogenicity and pathogenicity.

Haemolysin production (HLY), mannose resistant haemagglutinating activity (MRA), presence of antigens K1 and K5 and colicinogenicity (Col) were compared with LD50 for mice in 663 Escherichia coli strains, including 281 faecal, 129 urinary and 253 other extraintestinal isolates. Those isolates that LD50 value fell into less than or equal to 10(6) LD50 category were arbitrarily termed highly virulent (HV) and those which belonged to greater than or equal to 10(7) LD50 category were considered avirulent (AV). HV isolates occurred significantly more frequently (58%) among strains from different extraintestinal samples than from faeces (14%) or urine (16%). The incidence of HV strains was significantly higher in patients with sepsis (43%) or meningitis (100%) than in patients with enteritis (20%), urinary tract infections (UTI, 16%) or in healthy subjects (28%). The incidence of HV strains in the most frequent (O1, O2, O4, O6, O7, O18, O75) serogroups was significantly higher (60%) than in others (10%). Strains with different virulence markers (HLY, MRA, K1, K5, Col) belonged significantly more frequently to the HV group than those which failed to have these markers (44 vs 27%, 51 vs 25%, 83 vs 17%, 78 vs 27%, 52 vs 16%, respectively). Important role of antigen K1 playing in pathomechanism of meningitis was confirmed by data of analysis according to which significant difference was revealed in the incidence of HV strains between groups of isolates with MRA+K1+ (71%) and MRA+K1- (44%, p less than 0.02), or between groups of isolates with MRA+K1- and MRA-K1+ (91%, p less than 0.001). Moreover there were significant differences in the incidences of HV strains in K1+Col- (73%) and K1-Col+ (29%, p less than 0.001), and in K1+Col+ (86%) and K1-Col+ (29%, p less than 0.001) groups. Further evidence was given by those data that there were no significant differences between groups of HV strains with MRA+K1+ and MRA-K1+ (p greater than 0.05) or with K1+Col+ and K1+Col- (p greater than 0.1) properties. Isolates that possessed simultaneously two of MRA, HLY, Col markers were more pathogenic in LD50 assay than those that had one or the other of these markers alone. Strains in serogroup O18 killed mice significantly more frequently than those of other serogroups independently of having any virulence factor, suggesting that bacteria in serogroups O18 must have some special virulence other than K1, Col, MRA or K5. MRA+HLY+ HV strains occurred frequently in extraintestinal diseases (42%) supporting the preconception that these properties play an important role also in the pathomechanism of extraintestinal infections other than UTI.(ABSTRACT TRUNCATED AT 400 WORDS)

Antigens, Bacterial↗
PubMed1985

Induction of rat hepatic drug metabolizing enzymes by substituted urea herbicides.

Effects of eight structurally closely related substituted urea herbicides were investigated on the induction of cytochrome P-450 dependent monooxygenase enzyme complex, as well as on two conjugating enzymes after short-term treatment of rats. Liver microsomal cytochrome P-450 content was induced approximately by 50%. Cytochrome P-450 dependent monooxygenase activities showed a great variety depending on the substrate and on the herbicide. Two-18-fold induction was detected with 7-ethoxycoumarin, while up to 8-fold induction was measured with benzo(a)pyrene. Aldrin epoxidase activities were increased up to 3-fold, and aminopyrine N-demethylase activities were only slightly different from the control level. UDP-glucuronyltransferase and glutathione S-transferase activities were enhanced up to 2-fold. The results indicate that chemical structure of the related substituted urea compounds, the number of halogen substituents on their phenyl group exert a strong influence on the induction of monooxygenases.

7-Alkoxycoumarin O-Dealkylase↗
PubMed1982

Sensitizing activity to egg protein of an A1PO4-adjuvant full-virus influenza vaccine.

The sensitizing activity to egg protein of an A1PO4-adjuvant purified and concentrated influenza-A vaccine was examined in animal experiments and in man. Intravenous injection of ovalbumin caused anaphylactic symptoms and/or fatal anaphylactic shock in prevaccinated guinea-pigs. Ovalbumin-specific antibodies detectable by the passive haemagglutination reaction (PHA) appeared in the blood serum of the vaccinated animals. Model experiments with purified ovalbumin suggested that 1 human dose of the vaccine contained egg protein in the range from 0.1 to 1 ng, and that the antigenic effect of the vaccine grew to more than 10(3)-fold by its adsorption to A1PO4 gel. Adults who in previous years had been immunized with similarly prepared influenza vaccine several times responded with mild reactions; symptoms suggestive of hyperergy did not occur, irrespective of the vaccination history. In the prevaccination serum sample of some vaccines, ovalbumin-specific PHA antibodies were found up to titres independent of the number of the previous immunizations. The concentration of the ovalbumin-specific antibodies of the IgE class was by several orders of magnitude lower in the postvaccination samples than in the serum of some patients hypersensitive to egg protein.

Adjuvants, Immunologic↗
PubMed1980

[Analysis and fractionation of human tonsillar lymphocytes].

Among the human tonsillar cells, 28.0 +/- 3.1 and 45.14 +/- 2.16% were found to be E and EAC rosette forming cells, resp. In the course of the separation procedure with nylon cotton, in the authors' modification, the cells failing to form rosettes were almost entirely adhering irreversibly to the nylon wool. The 3H-thymidine incorporation in these cells was very intensive, and we supposed them to be T and B lymphoblasts. On the basis of E and EAC rosette formation, the percentage of T and B lymphocytes in human tonsils--as reported by various authors--is different. It may be supposed that methods employed by these authors did not demonstrate the equal extent of transformed forms of lymphocytes, i.e. lymphoblasts, whose amount may be influenced by the functional condition of tonsils.

B-Lymphocytes↗
PubMed1975

Absorption of circularly polarized gamma-radiation in L- and D-amino acids.

No difference within the experimental error (approximately 10(-3)) was observed in the absorption of right- and left-circularly polarized gamma-radiation in L- and D-tryptophan and tyrosine. For the measurements the 14.4 keV transition of 57Fe was used and the analysis of circularly polarized gamma-radiation was performed by Mössbauer method.

Amino Acids↗