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Biomedical subjects

R Marcos

Publications and source records attributed to R Marcos.

At least 109 records · Page 6Linked to original sources
PubMed1994

Genotoxicity of tritiated water in human lymphocytes.

The present study was carried out to evaluate the genotoxicity of tritium, administered as tritiated water, in peripheral blood human lymphocyte cultures. Sister-chromatid exchanges (SCE) and chromosome aberrations (CA) were scored as genetic endpoints. From our results we can conclude that beta-radiation from low concentrations of tritium was able to induce a significant increase in the frequency of CA, although it was ineffective in increasing the frequency of SCE.

Beta Particles↗
PubMed1994

The effect of cytochalasin-B concentration on the frequency of micronuclei induced by four standard mutagens. Results from two laboratories.

In a previous collaborative work, we have recently shown that the cytochalasin-B (Cyt-B) concentration used in the human lymphocytes cytokinesis-block micronucleus (CBMN) assay is an important variable in the baseline micronuclei (MN) frequency as well as in the percentage of binucleated cells obtained. Now we have investigated how Cyt-B concentration modulates the MN frequency induced in whole blood human lymphocyte cultures by two clastogens (ethyl methanesulphonate and mitomycin-C) and two aneugens (colchicine and vincristine sulphate). The experimental design includes six donors, two concentrations of Cyt-B (3 and 6 micrograms/ml), two concentrations of the four chemicals tested and the exchange of slides between laboratories. The statistical analysis of the results shows: (i) non-significant differences in the MN frequencies and in the toxicity results between scorers from each laboratory, except for 0.06 microM colchicine at 3 micrograms/ml Cyt-B; (ii) an induction of MN by all genotoxic agents tested, the frequencies being lower with 6 than with 3 micrograms/ml Cyt-B, in control and aneugen-treated cultures; and (iii) significant differences between Cyt-B concentrations in several treatments, obtaining lower MN frequencies and higher values for nuclear division index and % binucleated cells when 6 micrograms/ml Cyt-B was used. Bearing in mind these results as well as the toxicity data showing that 6 micrograms/ml Cyt-B is much more effective in blocking cytokinesis, we can conclude that the use of 3 micrograms/ml Cyt-B may overestimate the induced frequency of MN.

Adult↗
PubMed1993

Cytogenetic biomonitoring in a Spanish group of agricultural workers exposed to pesticides.

Sister chromatid exchanges (SCE) and chromosome aberrations (CA) were studied in the lymphocytes of 70 male agricultural workers occupationally exposed to several pesticides and 69 matched controls, without indication of exposure to pesticides, from 'El Maresme' (Barcelona, Spain), Comparison between both groups revealed that the individuals exposed to pesticides show substantial clastogenic effects in their lymphocytes without indication of increases in the basal frequency of SCE; moreover, these effects seem to be additive, increasing with the duration of exposure measured in years. When two confounding factors such as age and smoking habits are considered, we found that these factors increase significantly the expression of SCE although no effect was detected in the expression of CA.

Age Factors↗
PubMed1992

Genotoxicity of four herbicides in the Drosophila wing spot test.

The herbicides alachlor, atrazine, maleic hydrazide and paraquat were evaluated for genotoxicity in the Drosophila melanogaster wing spot test. Third-instar larvae trans-heterozygous for two recessive mutations of wing trichomes, multiple wing hairs (mwh) and flare (flr3), were treated by chronic feeding with different concentrations of the four herbicides. Feeding ended with pupation of the surviving larvae. The genotoxic effects were determined from the appearance of clones of cells with mwh, flr3 or mwh-flr3 phenotypes. Exposure to maleic hydrazide resulted in a significant increase in the frequency of the three categories of spots recorded (small single, large single and twin spots) in a dose-related fashion. Exposure to alachlor induced significant increases in both small and total spots at the four concentrations assayed and in the frequency of twin spots at the highest concentration tested (10 mM). Atrazine and paraquat also induced significant increases in both small and total spots at three of the four concentrations tested, without indication of a direct dose-effect relationship.

Acetamides↗
PubMed1992

Germinal and somatic mutation induction in Drosophila after treatment of larvae with tritiated water.

The present study was carried out to evaluate the mutagenicity of tritium, administered as tritiated water, in Drosophila melanogaster. Larvae were fed on tritium-treated medium during their development. Germinal and somatic mutation induction was detected by means of the sex-linked recessive lethal and the wing spot tests, respectively. Our results show that beta-radiation from tritium is able to induce significant increases in the frequency of both germinal and somatic mutations.

Animals↗
PubMed1992

Nutritional outcome and immunocompetence in mice fed on a diet containing raw field beans (Vicia faba, var. minor) as the source of protein.

Feeding growth mice on diets containing raw field beans (Vicia faba var. minor) as the only source of protein brought about an impairment in growth, muscle mass and liver weight. No changes in food consumption were observed, but the food intake:weight gain ratio was increased in those animals. Plasma protein, triacylglycerols and cholesterol values were not affected by the dietary treatment although serum glucose and zinc levels fell after legume intake as well as the number of circulating erythrocytes. The relative enlargement of thymus and spleen in the legume-fed mice was apparently accompanied by a reduction in the cell number and an increase in cell size, while the protein synthesis capacity followed differentiated patterns in both tissues when assessed through protein, DNA and RNA determinations. The haemagglutination titres and the number of rosette-forming cells were lower in those animals fed on the field bean diet as well as the splenic lymphocyte responses to phytohaemagglutinin, Concanavalin A or lipopolysaccharide mitogens used to evaluate the functional status of T and B lymphocytes. The present study describes, apparently for the first time in mice, the involvement of field bean intake in some immunological disturbances affecting both humoral- and cell-mediated aspects of the immune response.

Animals↗
PubMed1992

A collaborative study on the improvement of the micronucleus test in cultured human lymphocytes.

A collaborative study between two laboratories has been carried out in order to investigate the reproducibility of the cytokinesis-block micronucleus assay in human lymphocytes. A modified protocol to obtain good quality slides from whole blood cultures has been developed. The spontaneous frequencies of micronuclei in binucleated lymphocytes from five male subjects were evaluated in each laboratory at two cytochalasin-B concentrations (3 and 6 micrograms/ml). Our data show that 6 micrograms/ml cytochalasin-B was more effective than 3 micrograms/ml to arrest cytokinesis in all the donors analysed. The mean frequency of micronuclei in binucleated cells was significantly lower at 6 micrograms/ml compared to 3 micrograms/ml cytochalasin-B in both laboratories. The results obtained indicate a very high concordance between both sets of data supporting the validity of the proposed protocol.

Adult↗
PubMed1992

Genotoxicity studies on sertaconazole.

A series of 6 studies has been performed to evaluate the potential genotoxic effect of 7-chloro-3-[1-(2,4-dichlorophenyl)-2-(1H- imidazol-1-yl)ethoxy-methyl]benzo[b]thiophene (sertaconazole, FI 7045, CAS 99592-32-2). From these studies, the reverse mutation assay on Salmonella typhimurium, sex-linked recessive lethal mutations on Drosophila and genetic mutations in cultured mammal cells allowed to study the genetic mutations in prokaryotes and eukaryotes. In vitro and in vivo chromosomal aberrations were studied using human lymphocytes cytogenetic test, micronucleus test and sister chromatid exchange test. The results obtained in these studies, which are complemented one another, demonstrated that sertaconazole did not induce any signs of promutagenic, mutagenic or clastogenic activity or interference with the chromosomal segregation process.

Animals↗
PubMed1991

Genotoxicity studies with the unstable zeste-white (UZ) system of Drosophila melanogaster: results with ten carcinogenic compounds.

To increase the number of chemicals tested using the zeste-white (UZ) somatic mutation assay, ten selected carcinogens (acetamide, acrylamide, benzo(alpha)pyrene, cyclophosphamide, diethylstilbestrol, 4-nitroquinoline N-oxide, propyleneimine, safrole, thiourea, and o-toluidine) have been evaluated in this assay. Our results show that all the compounds tested produce significant increases in the eye spot frequency at, at least, one of the concentrations assayed, indicating that the zeste-white assay appears to be highly sensitive to these carcinogenic compounds. That is in agreement with data previously reported by other authors.

4-Nitroquinoline-1-oxide↗
PubMed1991

Additional data in support of the quadruplicated white-ivory reversion system to test for somatic genotoxicity in Drosophila melanogaster.

Cyclophosphamide, ethyl methanesulfonate, propyleneimine and tritiated water were tested in a new short-term somatic mutation bioassay, previously described by Green and coworkers (1986), to evaluate the suitability of the quadruplicated white-ivory system of Drosophila melanogaster for genotoxicity testing of chemicals. A 2.9-kb tandemly duplicated sequence of w+ within a w+ gene is responsible for the white-ivory phenotype. Reversion of wi to w+ is, in general, associated with the loss of the appended 2.9 kb or other alterations affecting this duplicated region. The appearance of light (white or nearly white) phenotypes could be due to the loss of some wi copies. Thus, in the eyes of adult males resulting from treated larvae, we can detect 2 types of sectors (red and light) on the orange-yellow background. Our results indicate that the genetic system used in this somatic assay is sensitive to the genotoxic effects of the 4 compounds tested. All 4 compounds tested were positive. Tritiated water had weak effects, cyclophosphamide was characterized by small revertant clones and ethyl methanesulfonate and propyleneimine by large clone size. From the available data, we feel that the wi system can be considered of potential value for genotoxicity testing.

Animals↗
PubMed1990

Induction of mitotic micronuclei by the pyrethroid insecticide fenvalerate in cultured human lymphocytes.

The pyrethroid insecticide fenvalerate was tested for its ability to induce mitotic micronuclei in cytokinesis-block cells of cultured human peripheral blood lymphocytes at concentrations ranging from 10 to 50 micrograms/ml. We observed that fenvalerate induces a significant increase in the frequency of micronuclei, indicating clastogenic and/or aneugenic activity. Our results complement previous data on the genotoxicity of this compound in human lymphocytes.

Alkylating Agents↗
PubMed1990

Mutagenic evaluation of the organophosphorus insecticides methyl parathion and triazophos in Drosophila melanogaster.

The possible genotoxic effects of the organophosphorus insecticides methyl parathion and triazophos were evaluated by their ability to induce gene and chromosome mutations in male germ cells of Drosophila melanogaster. Sex-linked recessive lethal (SLRL), total and partial sex-chromosome losses (SCL), and non-disjunction (ND) assays were conducted. The routes of administration included adult feeding, injection, and larval feeding. Methyl parathion was unable to induce point mutations or chromosome mutations, although a small increase in the frequency of non-disjunction was detected after larval treatment. Triazophos induced point mutations when assayed in the SLRL test and induced a weak increase in the non-disjunction frequency, but gave negative results in the SCL test.

Animals↗
PubMed1990

Sister chromatid exchange in lymphocytes of agricultural workers exposed to pesticides.

Sister chromatid exchange (SCE) was studied in the lymphocytes of 27 agricultural workers occupationally exposed to several pesticides and 28 matched controls from el Maresme, an agricultural area near Barcelona. Comparison between both groups with the t-test did not reveal significant differences. These negative findings suggest that, possibly, the exposure level is too low to increase SCE in human lymphocytes in vivo. Our results indicate that smokers, both the workers and the controls, had a higher SCE frequency than non-smokers, in agreement with previous data reported by different authors.

Adult↗
PubMed1989

Mitotic arrest induced by fenvalerate in human lymphocyte cultures.

The pyrethroid insecticide fenvalerate was tested for its ability to induce C-mitosis in cultured human peripheral blood lymphocytes at concentrations ranging from 2-50 micrograms/ml. We observed a significant increase in C-mitotic figures, indicating that this compound was effective in producing disturbance of spindle function.

Cells, Cultured↗
PubMed1989

Analysis of cytogenetic damage induced in cultured human lymphocytes by the pyrethroid insecticides cypermethrin and fenvalerate.

Two pyrethroid insecticides, cypermethrin and fenvalerate, were tested for their ability to induce chromosome structural aberrations and sister chromatid exchanges in cultured human peripheral blood lymphocytes. Fenvalerate, but not cypermethrin, increased the frequencies of chromosome-type aberrations and sister chromatid exchanges. In addition, both pyrethroids affected the cell cycle causing a decrease in the proliferative rate index at concentrations greater than 10 micrograms/ml.

Cells, Cultured↗
PubMed1988

Genotoxicity studies with four organophosphorus insecticides using the unstable white-zeste system of Drosophila melanogaster.

The present study was carried out to evaluate the suitability of the unstable white-zeste system in Drosophila melanogaster by testing 4 organophosphorus insecticides for potential genotoxic activity: dimethoate, fenitrothion, malathion, and methyl parathion. In view of the high sensitivity to insecticides of the unstable zeste strain used in this assay and the negative results obtained in this work, the white-zeste system does not appear to be sufficiently accurate for the evaluation of the mutagenic potential of specifically toxic chemicals, like insecticides.

Animals↗