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Biomedical subjects

L Ebringer

Publications and source records attributed to L Ebringer.

At least 55 records · Page 3Linked to original sources
PubMed1988

Effect of elevated temperature on genotoxicity of chemotherapeuticals toward Euglena gracilis.

A collection of 20 compounds was tested for their ability to induce a permanent loss of chloroplasts from Euglena gracilis cells under conditions increasing the sensitivity of the flagellate to genotoxic compounds, viz. in the resting medium and at an elevated temperature. Streptomycin, dihydrostreptomycin, gentamicin, kanamycin and partially chloramphenicol exhibited mutagenic effects. Eight antibiotics eliminated chloroplasts only from growing cultures and seven antibiotics did not induce the mutation at all.

Animals↗
PubMed1986

Benzothiazolium salts--relationships between their structure, toxicity and effect on the plastid system of Euglena gracilis.

The effects of 41 benzothiazolium salts on Euglena gracilis were characterized with regard to the influence on growth and on chlorophyll synthesis, and to their ability to induce permanent loss of chloroplasts. Some salts induced white mutants of E. gracilis (the first benzothiazole derivatives with this activity). The relationship between the biological effect and chemical structure was confirmed and expressed quantitatively by means of Free - Wilson and Fujita - Ban analysis.

Animals↗
PubMed1986

Relationships between structure of 5-nitro-2-furylethylenes and their SOS-function-inducing activities in Escherichia coli.

The SOS-function-inducing activities of 36 furylethylenes were characterized in Escherichia coli K12. The induction of the SOS function was assayed by monitoring the beta-galactosidase activity in the sulA::lacZ fusion strain PQ 37. To correct for the inhibitory effects of test compounds on mRNA or protein synthesis, the level of the constitutive alkaline phosphatase was assayed in parallel. Tested furylethylenes included nine alkylesters and eleven N-alkylamides of 5-nitro-2-furylacrylic acid (NFAA) and fourteen derivatives differing not only in substituents at exocyclic double bond, but also in the position 5 of the furan ring. The induction of the SOS-function by the derivatives depends on the presence of 5-nitrofuran centre in their molecule; side chains in the position 2 modify the degree of SOS response. SOS-inducing potency of n-alkyl congeners decreases with increasing lipophilicity. Effect of derivatives with branched alkyl substituents is lower than expected from the behavior of the n-alkyl homologues. All derivatives with positive effect on SOS-function in E. coli show mutagenic activity on Salmonella typhimurium TA98 in Ames test.

Acrylates↗
PubMed1985

Hyperthermia and other factors increasing sensitivity of Euglena to mutagens and carcinogens.

The effects of different factors (temperature, light, enzymic activation) on the ability of selected mutagens and carcinogens to induce hereditary bleaching of Euglena gracilis were investigated. In the resting medium, the elevation of incubation temperature from 25 degrees C to 37 degrees C increased significantly the effect of all compounds tested on the frequency of bleached mutants of E. gracilis. The effect of light is not so unambiguous. While nitrosoguanidine (NG) exhibited practically the same bleaching activity both in the light and dark, the mutagenic effect of sodium azide (SA), nitrovin (NV), nitrosoethylurea (NEU), and benzo(a)pyrene (BP) was decreased in light. On the other hand, the light increased the bleaching activity of 5-nitro-2-furylacrylic acid (NFAA) significantly. The activation mixture S9 increased bleaching effect of NFAA and BP, whereas other mutagens were partially (NG and SA) or completely (NV and NEU) inactivated.

Carcinogens↗
PubMed1985

Quantitative relationships between lipophilicity and mutagenic effects of N-substituted amides of 3-(5-nitro-2-furyl)-acrylic acid on Salmonella typhimurium.

Mutagenic effects of 10 N-alkylamides of 3-(5-nitro-2-furyl)-acrylic acid were assessed in two strains of Salmonella typhimurium TA100 (rfa+ and rfa-). Experimental data were confronted with physiologically based compartment model comprising passive membrane transport, metabolical inactivation in cytoplasm and formation of a reactive intermediate which is responsible for receptor modification. The quantitative dependences observed between mutagenicity and lipophilicity indicate that, in both cases, the drug-receptor interaction takes place in a hydrophobic compartment localized in the cytoplasm. The mutagenic potency of some derivatives was influenced also by stericity.

Acrylates↗
PubMed1982

Mutagenic effects of two nitrofuran food preservatives.

Two structurally related food additives, 3-(5-nitro-2-furyl)acrylic acid (5-NFAA) and 2-(2-furyl)-3-(5-nitro-2-furyl)acrylamide (AF-2) showed a marked mutagenic effect on Salmonella typhimurium strains TA100 and TA98 and Escherichia coli WP2 uvrA+ and WP2 uvrA. On the molar basis 5-NFAA was about two orders of magnitude less effective than AF-2. In Salmonella typhimurium TA100 anaerobic conditions stimulated the mutagenic effect of 5-NFAA which was more pronounced in nitrofuran-reductase deficient strain of Salmonella typhimurium TA100 FR50. 5-NFAA increased the number of isoleucine revertants and induced mitotic recombination at tryptophan, threonine and adenine loci of the diploid strains Saccharomyces cerevisiae a/b and Saccharomyces cerevisiae SBTD. Activity of 5-NFAA was lower than that of AF-2. The test on sex-linked recessive lethal mutations in Drosophila melanogaster indicated that only 5-NFAA is mutagenic, increasing the mutation frequency about 10-fold above the control. Results with AF-2 fell within the control range.

Acrylates↗
PubMed1981

Mutagenic activities of simple nitrofuran derivatives. I. Comparison of related compounds in the phage inductest, chloroplast-bleaching and bacterial-repair and mutagenicity tests.

Several simple furan and nitrofuran compounds were tested for mutagenicity and related biological activities, in the Ames test, the bacterial repair test, the prophage-induction test and the chloroplast-bleaching test. Only those compounds having the nitro-group were found to be active in the test. If the nitro-group was in the beta instead of the alpha position, the mutagenic activity was much reduced (0.3 revertants per nanomole, the other simple nitrofurans producing 5-15 reversions per nanomole, as did 5-nitrofuran and 5,2-dinitrofuran). The vinyl-group-containing compound, 5-nitro-2-furylacrylic acid, was by one decadic order more effective both in the Ames test and in the prophage-induction test. In the repair tests all nitrofurans displayed a much higher dependence on the recA-repair system than on the uvrA system. For 2 compounds, the dinitrofuran and, especially, the 5-nitrofuraldehyde, the urA cells were even less sensitive than the wild-type cells.

Animals↗
PubMed1980

Mutagenicity of nitrofuran drugs in bacterial systems.

The mutagenic activity of 5 nitrofuran drugs (furadantin, furoxon, furacin, benzazon VII and lampit) was tested on strains Salmonella typhimurium TA 100, TA 1535, TA 1438 and Escherichia coli WP2 uvrA+ and WP2 wrA. All nitrofurans tested has a marked mutagenic effect on strain TA 100 and, partially, on strain TA 1535 except for furoxon which was strongly toxic for this strain. No significant mutagenic effects of the drugs were observed with strain TA 1538. With the exception of lympit, all drugs exerted a mutagenic action on E coli WP2 vwA but no on WP2 uvA+ which has an intact excision repair system. The only drug exerting a mutagenic effect on the latter strain was furoxon. All five nitrofurans exhibited a positive repair test. The results support the notion that the nitrofuran mutagens under study induce single base substitutions.

Chemistry↗
PubMed1980

Effect of some benzthiazol derivatives on Euglena gracilis.

6-Substituted derivatives of 2-benzthiazolthiol and allyl (2-benzthiazolylthio)acetate exhibit, after an exposure to light, and inhibitory action on the division of dark-depigmented Euglena cells, as well as the synthesis of chlorophyll. These substances also have a marked inhibitory effect on the devlopment of plastids in nondividing cells maintained under resting conditions. No induction of heterotrophic plastid--free mutants was found under growth or resting conditions.

Animals↗
PubMed1980

Social deprivation amongst short stay psychiatric patients.

Two samples of newly admitted psychiatric patients were examined. Of 558 patients admitted during one year, 76 (13.7 per cent) came in from transitory accommodation or no fixed abode; of 456 patients discharged 131 (28.7 per cent) either changed address during their stay in hospital or left without known accommodation. Of 102 patients in the wards and day hospital on one day, 29 (28.4 per cent) came in from transitory accommodation or no fixed abode, 66 (64.7 per cent) were unemployed, 51 (50 per cent) were living alone. Of the 74 inpatients 30 (40.5 per cent) were homeless and 27 (36.5 per cent) had no visitors. These results indicate that many patients have lost their community supports by the time they reach hospital.

Community Mental Health Services↗
PubMed1978

Antimicrobial effects of some benzthiazol derivatives.

Substitution with NO2, Cl, Br and I into position 6 of 2-benzthiazolthiol derivatives increased their antimicrobial efficiency while the SH group is preserved. This increase affected both G+ and G--bacteria, mycobacteria and some fungi. The degree of efficiency of the benzthiazol derivatives is also influenced by the substituent in position 2.

Anti-Bacterial Agents↗
PubMed1977

A survey of a long-stay psychiatric population: implications for community services.

Two hundred and twenty long-stay psychiatric patients were surveyed by means of semi-standardized interviews and by obtaining information from nursing staff and case records. Each patient's needs for accommodation and employment were assessed as if immediate discharge from hospital were being contemplated. The results of the exercise emphasize the need for long-stay to permanent accommodation. The validity of this method of assessing community care requirements is discussed.

Activities of Daily Living↗
PubMed1976

Mutagenic action of nitrofurans on Euglena gracilis and Mycobacterium phlei.

There is a pronounced difference between the action of antibiotics and nitrofurans on Euglena gracilis. Those antibiotics that induce hereditary loss of chloroplasts do so only when they affect dividing cells. On the other hand, nitrofurans induce a mass mutation in both dividing and nondividing cells (under conditions of continuous illumination of cultures). It was found that a breakdown product, 5-nitro-2-furaldehyde, is liberated from furadantin and furoxone. This intermediate is responsible for the observed specific mutagenicity of 5-nitrofuran drugs. The mutagenic action of 5-nitro-2-furaldehyde is very similar to that of nitrosoguanidine. Both compounds induce bleached mutants of E. gracilis when acting on growing or resting cells, regardless of the dark or light conditions. Similarly, both compounds induce reverse mutations in auxotrophic strains of Mycobacterium phlei.

Animals↗