Suppressing effect of antimutagenic flavorings on chromosome aberrations induced by UV-light or X-rays in cultured Chinese hamster cells

Chromosome aberrations induced by UV-light or X-rays were suppressed by the post-treatment with antimutagenic flavorings, such as anisaldehyde, cinnamaldehyde, coumarin, and vanillin. UV- or X-ray-irradiated surviving cells increased in the presence of each flavoring. X-ray-induced breakage-type and exchange-type chromosome aberrations were suppressed by the vanillin treatment in the G1 phase of the cell cycle and a greater decrease in the number of X-ray-induced chromosome aberrations during G1 holding was observed in the presence of vanillin. Furthermore, a greater decrease in the number of X-ray-induced DNA single-strand breaks was observed in the presence of vanillin. Treatment with vanillin in the G2 phase suppressed UV- and X-ray-induced breakage-type but not exchange-type chromosome aberrations. The suppression of breakage-type aberrations was assumed to be due to a modification of the capability of the post-replicational repair of DNA double-strand breaks. These G1- and G2-dependent anticlastogenic effects were not observed in the presence of 2',3'-dideoxythymidine, an inhibitor of DNA polymerase beta. Based on these results, the anticlastogenic effect of vanillin was considered to be due to the promotion of the DNA rejoining process in which DNA polymerase beta acts.     

Suppressing effect of vanillin on chromosome aberrations that occur spontaneously or are induced by mitomycin C in the germ cell line of Drosophila melanogaster.

In order to investigate the anticlastogenic effect of vanillin on ring-X loss, D. melanogaster females exposed to different vanillin concentrations were crossed with non-treated, MMC- or MMS-treated males. The results obtained with this in vivo investigation showed a significant inhibition of vanillin in the frequencies of spontaneous ring-X loss--59, 56, 38 and 36%--at the different concentrations used. In addition, vanillin treatment caused a significant suppression of MMC-induced ring-X loss. This decrease was observed only in the first 3 days after the interruption of vanillin treatment and at the concentrations of 0.5 and 1% of this flavoring agent. In contrast, vanillin did not show any effect on chromosome loss provoked by MMS. Therefore, the ring-X loss-decreasing effect of vanillin seemed to depend on the quality of DNA lesions and consequently on a specific enzymatic repair process present in the oocytes of D. melanogaster.     

Body-weight and chromosome aberrations induced by X-rays in somatic cells of Drosophila melanogaster

Summary Variations in suppression efficiency were observed among nonsense mutations at different locations within the lysozyme gene (e) of T4 phage. The present experiments using three amber mutants in lysozyme gene indicate such variations presumably depend upon the base sequences neighboring to the nonsense mutations.Part of this work is the thesis work of one of the authors (E.A.) and was reported at the Annual Meeting (1968) of Genetic Society of Japan     

桂皮醛对DSS诱导的溃疡性结肠炎小鼠的保护作用研究

为探讨桂皮醛(CA)对实验性溃疡性结肠炎(UC)小鼠的保护作用及其初步机制,用柳氮磺胺吡啶(300 mg/kg)做为阳性对照,CA分别以150、250、500 mg/kg的剂量对3％葡聚硫酸钠(DSS)诱导的UC小鼠进行灌胃治疗.观察小鼠给药前后状态的变化并进行DAI评分,HE染色法观察小鼠结肠组织形态的变化并进行病理...     

Effects of vanillin on sister-chromatid exchanges and chromosome aberrations induced by mitomycin C in cultured Chinese hamster ovary cells

Effects of vanillin on the induction of sister-chromatid exchanges (SCEs) and structural chromosome aberrations by mitomycin C (MMC) were investigated in cultured Chinese hamster ovary cells. Vanillin induced neither SCEs nor chromosome aberrations by itself. However, an obvious increase in the frequency of SCEs was observed when MMC-treated cells were cultured in the presence of vanillin. The effect of vanillin was S-phase-dependent. On the contrary, the frequency of cells with chromosome aberrations was significantly decreased by the post-treatment with vanillin at G2 phase.     

Suppressing effects of glucan on micronuclei induced by cyclophosphamide in mice.

The effect of pretreatment with carboxymethylglucan (CMG) on the frequency of micronuclei induced by cyclophosphamide administration in mice was evaluated. Two doses of CMG (50 mg/kg body weight) injected either intraperitoneally 24 h or intravenously 1 h prior to two cyclophosphamide administrations (80 mg/kg) significantly decreased the frequency of micronucleated PCE in bone marrow. Of two evaluated derivatives of carboxymethylglucan, the K3 derivative was most efficient. The results show that it is possible to achieve a suppressive effect of soluble carboxymethylglucan prepared from Saccharomyces cerevisiae against cyclophosphamide mutagenicity. The notion may be useful for glucan's effects against pharmacocarcinogenesis. Therapeutic application of glucan with cyclophosphamide therapy may provide a remarkable decrease of the secondary tumour risk. The utilization of these results for human patients needs to be considered.     

Sister-chromatid exchange and chromosome aberrations induced by paracetamol in vivo in bone-marrow cells of mice.

Sister-chromatid exchange (SCE) and chromosome aberrations (CA) induced by paracetamol (PC), a common analgesic, were studied in vivo on bone-marrow cells of mice. The trend tests for the evidence of dose-response effects for both SCE and CA were significant. The significant increase in SCE as well as CA induced by PC may be attributed to the fact that PC can induce genotoxicity through DNA damage. Thus, the present study indicates that PC was genotoxic in vivo in bone-marrow cells of mice.     

Frequency of spontaneous chromosome aberrations in mice: effects of age

In this paper, we present data on chromosome aberration frequencies in mice which served as unexposed controls in a variety of radiation and chemical toxicology experiments conducted in our laboratory in recent years. All chromosome aberration data were obtained by chromosome painting. In peripheral blood lymphocytes from 102 animals, the frequencies of translocations and insertions increased significantly with age. No increase with age was seen for dicentrics or acentric fragments. When the data were analyzed by strain, the age-related increase in translocation frequencies was observed only in the 71 homozygous C57BL/6 mice and not in any of the three heterozygous strains. Very few aberrations of any type were observed in 62 bone marrow samples, and no effect of age was seen for any aberration type in this tissue. These results are similar to those observed in unexposed humans, and suggest that the increase in translocations is not the result of accumulated damage from chronic 'background' environmental exposures but instead may be due to biological processes associated with aging.     

Chromosome aberrations induced in human lymphocytes by in vitro and in vivo X-rays

A dose-effect curve is presented obtained by analysis of dicentric chromosomes and centric ring chromosomes in lymphocyte metaphase spreads of three healthy volunteers after in vitro 100 kV X-ray-irradiation of peripheral blood samples. This calibration curve follows a linear quadratic equation, y=c+alpha D+beta D(2), with the coefficients: y=(0.0005+/-0.0001)+(0.0355+/-0.0066)D+(0.0701+/-0.0072)D(2). The model is based on 13.231 first-division metaphases analyzed after in vitro exposure to doses ranging from 0.1 to 2.0 Gy at a dose rate of 0.4 Gy min(-1). Significant overdispersion of the observed chromosomal aberrations was evident for dose points 1.0 and 2.0 Gy, respectively. The calibration curve was applied to derive equivalent whole body doses of three subjects after suspected extensive exposure to diagnostic X-rays.     

Cytology of aberrations induced by X-rays in oocytes of Drosophila melanogaster.

200 first-division configurations were analyzed for cytological aberrations induced by X-rays in late meiotic prophase in oocytes of Drosophila melanogaster. For the 3000 and 6000 r doses, 38 and 66%, respectively, were classified as abnormal. The aberrant divisions included displacement of the chromosomes suggesting their non-disjunction, loss of a whole chromosome, fragments and heterologous exchanges and unidentifiable aberrations. Non-disjunctional chromosomes were free of heterologous exchanges. The concept that a majority of X-ray-induced dominant lethals is due to chromosomal breakage is supported by the findings of the present study.     

Elimination of spontaneous and chemically induced chromosome aberrations in mice during early embryogenesis

Summary NMRI mice () were treated with 0.25 mg/kg body weight Trenimon (2,3,5-triethyleneiminobenzoquinone-1,4) in the preovulatory phase just before ovulation. Then they were mated with untreated males.The female mice were dissected 45 h after application of this mutagen. The preimplantation embryos, being in a 2-cell stage, were flushed out of the oviduct and cultured in vitro for 60 h. Of the cultured embryos 87.7% reached the blastocysts stage in the control series, whereas only 49.7% did so in the experiments.Some of the females were dissected on the 14th day post conception (p.c.) and the number of dead and living implants was determined.Furthermore, the 9.5- and 13.5-day-old embryos were cytologically investigated, to determine the frequency of chromosomal aberrations.Of the unfertilized oocytes 76.2% deriving from mice treated with 0.25 mg/kg Trenimon, were aberrant in the stage of metaphase II (Röhrborn and Hansmann, 1971).Comparing Röhrborn's and Hansmann's results (1971) to our own findings a continous elimination of chromosome aberration is clearly to be seen during early embryogenesis. The biological selection takes place in the pre- as well as in the early and late postimplantative phase.     

Induction of chromosome aberrations and cell killing in Syrian hamster fibroblasts by gamma-rays, X-rays and fast neutrons

Chromosome aberrations were scored in BHK21 C13 Syrian hamster fibroblasts, exposed to 60Co gamma-rays, 250 kV X-rays, 15 MeV neutrons or neutrons of mean energy 2.1 MeV produced from the 9Be(d,n)10B reaction. The cells were irradiated in stationary phase, where they are concentrated in the G1 phase of the cell cycle. Within experimental uncertainty there was no detectable difference between the responses to 60Co gamma-rays and to 250kV X-rays. The r.b.e. for the production of dicentrics, based on the 'one-hit' component of response, was (5 +/- 2) for the 15 MeV neutrons and (12 +/- 5) for the 2.1 MeV neutrons. For each radiation, a graph of the proportion of cells without a dicentric, centric ring or acentric fragment corresponded closely to the survival curve for stationary-phase cells obtained in the same experiment.     

The induction of chromosome aberrations in mouse dictyate oocytes by X-rays and chemical mutagens.

Oocytes were collected from female mice and matured in vitro to Metaphase I during the first or third week after treatment with a dose of 400 rad X-rays, 1.6 mg/kg triethylenemelamine (TEM) or 75 mg/kg isopropylmethanesulphonate (IPMS). In week 1 the mean number of oocytes per female was similar for all treatments but in week 3 irradiated females yielded fewer oocytes than the chemically treated or control females. In week 1 the proportion of oocytes maturing was smaller in irradiated females than in the other groups but in week 3 was similar in all groups.Structural chromosome aberrations, scored in the Metaphase I oocytes, were of the chromatid or isochromatid type and involved gaps, breaks, fragments, intrachanges and interchanges. Aberration frequency did not increase with time after either of the chemical mutagens but after irradiation was higher in the third week than in the first week. The aberration yield from IPMS-treated females was similar at both sampling times, while a lower yield was recorded in week 3 following TEM treatment than in week 1.     

Distribution pattern and dose-response-relationship of chromosome aberrations in human lymphocytes induced in vitro by 60Co gamma-rays and 110 kV X-rays.

Peripheral blood lymphocyte culture system was used to construct reference dose-response curves for 60Co gamma-rays and 110 kV X-ray-induced chromosome aberrations at 6 dose points ranging from 0.25 to 4.0 Gy. Qualitative and quantitative differences between these two types of radiation for the yield of induced aberrations and their distribution pattern were analysed. Experimental data of aberration yields were compared after fitting them to five different dose-response models. The yields of chromosome aberrations in particular dicentrics, gave a good fit to linear-quadratic besides linear and power models. In this model, single-track events predominated over double-track events for both the qualities of radiation used. The pattern of distribution was mainly Poisson for dicentrics but gave a conflicting result for acentrics which was in excess.