Chromosome aberrations in employees from fossil-fueled and nuclear-power plants

Chromosome aberrations were scored in 59 persons from fossil-fueled plants, in 89 persons from nuclear-power plants and in 23 controls. A significant increase in acentric chromosome fragments and dicentric chromosomes compared to the control group was observed in both types of workers. Moreover, the number of abnormal cells was significantly greater in workers of conventional plants than in those of nuclear-power plants. When adjusted for loss of lymphocytes according to a half-life of 3 years, this difference was also significant for the number of dicentric chromosomes observed. A significant effect of length of exposure or of frequency of radiological examinations could be discerned only in the group of workers from conventional plants.     

Chromosome aberrations and rogue cells in lymphocytes of Chernobyl clean-up workers

A cytogenetic analysis was performed on peripheral blood lymphocytes from 183 Chernobyl clean-up workers and 27 control individuals. Increased frequencies of chromosome aberrations were associated with exposure to radiation at Chernobyl, alcohol abuse and a history of recent influenza infection. However, only approximately 20% of Chernobyl clean-up workers had an increased frequency of dicentric and ring chromosomes. At the same time, an increased frequency of acentric fragments in lymphocytes of clean-up workers was characteristic. The use of multivitamins as dietary supplement significantly decreased the frequency of chromosome aberrations, especially of chromatid breaks. Rogue cells were found in lymphocytes of 28 clean-up workers and 3 control individuals. The appearance of rogue cells was associated with a recent history of acute respiratory disease (presumably caused by adenoviral infection) and, probably, alcohol abuse. Dicentric chromosomes in rogue cells were distributed according to a negative binomial distribution. Occurrence of rogue cells due to a perturbation of cell cycle control and abnormal apoptosis is suggested.     

Chromosome aberrations in lymphocytes of residents living in buildings constructed with radioactively contaminated rebars

Using the G-banding technique, we examined lymphocytes from 90 individuals (43 males and 47 females, median age 31 years) living in buildings constructed with radioactively contaminated rebars. Forty-five nonexposed control subjects (22 males and 23 females, median age 30 years), matched to the radiation-exposed individuals by sex and age, were selected for comparison. At least 500 metaphases were checked for each individual. All recognizable structural aberrations of chromosomes or chromatids were recorded. After adjusting for age and smoking status, both the percentage of cells with aberrant chromosomes (PCAC) and the number of aberrant chromosomes per 100 cells (NAC) were found to be significantly higher in the radiation-exposed females than in the control females (p < 0.05 for PCAC and NAC). This difference, however, was not observed in the comparison of radiation-exposed and control males. This suggests a possible interaction between sex and radiation exposure in their effects on chromosome aberrations.     

Chromosome aberrations and sister chromatid exchanges in cultured human lymphocytes treated with sodium metabisulfite, a food preservative

The aim of this study was to investigate the ability of sodium metabisulfite (SMB) which is used as an antimicrobial substance in food, to induce chromosome aberrations (CA) and sister chromatid exchanges (SCE) in human lymphocytes. SMB-induced CAs and SCEs at all concentrations (75, 150 and 300 μg/ml) and treatment periods (24 and 48 h) dose-dependently. However, SMB decreased the replication index (RI) and the mitotic index (MI) at the concentrations of 150 and 300 μg/ml for 24 and 48 h treatment periods. This decrease was dose-dependent as well.     

Chromosome aberrations in rotogravure printing plant workers

Chromosome analysis was carried out in peripheral lymphocytes of 3 groups of workers. In 42 rotogravure printers exposed to rotogravure printing dyes and highly purified toluene at working air concentrations in the range of 104-1170 ppm (390-4380 mg/m3) for 13 years on average, an increased incidence of aberrant cells and chromatid breaks was observed. In 28 office and technical employees of the same plant, more than half of whom worked 2 h daily in the rotogravure workshop, an increased percentage of aberrant cells and chromatid breaks was also found. The difference between the 2 groups working in the printing plant and 32 controls was highly significant. The high incidence of aberrations could be explained by the exposure to toluene, but the influence of rotogravure printing dyes cannot be excluded. Smoking and high air pollution in the urban area were contributing factors in all 3 groups.     

香蕉苗试管繁殖染色体数量畸变的研究

对在常规培养以及高６－ＢＡ、高腺嘌呤、高继代数、长继代时间等培养条件下,分化芽的染色体数目变化的规律以及一些苗期变异性状与染色体数量变异的关系进行了研究。主要结果有：（１）以上因素均能不同程度地促使染色体数量畸变率增高。其中,高腺嘌呤和高继代数加长继代时间２种处理效果最明显;（２）细胞畸变以非整倍体为主,可以在培养中逐代积累、增加。植株畸变以混倍体为主,非整倍体次之。植株畸变率明显低于细胞畸变率;（３）观察到一些苗的畸变的类型以及其对应的细胞学变化。结果显示,高继代代数的苗畸变率显著增高;在继代培养中,采取用核酸盐或高激动素以及片面地选用分化率高的芽丛作进一步扩大培养,以提高分化率的做法是危险的;根据苗期的形态特征,可将部分变异苗清除     

Chromosome variation in protoplast-derived potato plants

Summary Chromosomes have been studied in protoplast-derived potato plants of the tetraploid cultivars Maris Bard and Fortyfold. A high degree of aneuploidy was found amongst the regenerants of both cultivars but the nature of the chromosome variation differed. The Maris Bard regenerants were characterised by high chromosome numbers, a wide range of aneuploidy (46–92) and a low percentage of plants with the normal chromosome number (2n = 48), whereas a much higher proportion of the Fortyfold regenerants had 48 chromosomes and the variants were within a more limited aneuploid range. In both cultivars chromosome variation was found between calluses, within calluses and even within shoot cultures. The origin of the chromosome variation and the differences found between the two cultivars are discussed.We regret to report the death of Emrys Thomas since the initiation of this work     

Chromosome aberrations in workers at a tannery in Iraq

Blood samples were collected from 17 healthy chromium-exposed workers at a tanning plant near Baghdad city and 13 controls matched for age, period of service and social background. For each individual more than 100 lymphocyte metaphases were examined. The results showed no significant differences in the per cell frequencies of chromatid and isochromatid gaps, single chromatid breaks, various chromosome-type aberrations and all aberrations combined. However, smoking workers exhibited statistically higher frequency of chromosome-type aberrations than non-smoking workers and smoking controls.     

Chromosome aberrations in hothouse workers coming in contact with pesticides

The frequency of chromosome mutations in the peripheral blood lymphocytes has been studied in 40 greenhouse workers professionally contacting with a complex of pesticides. The frequency of chromosome aberrations in the group of workers amounts to 6.0 +/- 0.3%, that is higher than the frequency of aberrations in the control group.     

Chromosome aberrations in solid tumors have a stochastic nature

An important question nowadays is whether chromosome aberrations are random events or arise from an internal deterministic mechanism, which leads to the delicate task of quantifying the degree of randomness. For this purpose, we have defined several Shannon information functions to evaluate disorder inside a tumor and between tumors of the same kind. We have considered 79 different kinds of solid tumors with 30 or more karyotypes retrieved from the Mitelman Database of Chromosome Aberrations in Cancer. The Kaplan–Meier cumulative survival was also obtained for each solid tumor type in order to correlate data with tumor malignance. The results here show that aberration spread is specific for each tumor type, with high degree of diversity for those tumor types with worst survival indices. Those tumor types with preferential variants (e.g. high proportion of a given karyotype) have shown better survival statistics, indicating that aberration recurrence is a good prognosis. Indeed, global spread of both numerical and structural abnormalities demonstrates the stochastic nature of chromosome aberrations by setting a signature of randomness associated to the production of disorder. These results also indicate that tumor malignancy correlates not only with karyotypic diversity taken from different tumor types but also taken from single tumors. Therefore, by quantifying aberration spread, we could confront diverse models and verify which of them points to the most likely outcome. Our results suggest that the generating process of chromosome aberrations is neither deterministic nor totally random, but produces variations that are distributed between these two boundaries.     

Chromosome variation in wheat plants regenerated from cultured immature embryos

Summary A cytological study has been made of plants regenerated from cultured immature embryos of four wheat cultivars (Triticum aestivum, 2n = 6x = 42). In total, 29% of the 192 plants examined were aneuploid with a range in chromosome numbers of 38–45. Evidence of chromosome structural changes was also found. This variation occurred in regenerants of all four cultivars, but there were large differences in the proportions of aneuploids arising from individual cultures which meant that no significant differences could be demonstrated between cultivars. Chromosome abnormalities were present in plants regenerated both from embryogenic cultures and from cultures in which the origin of shoots could not be distinctly defined.     

Chromosome aberrations in workers at a storage battery plant in Iraq

The present study deals with the determination of the incidence of chromosome changes in workers at a factory making storage batteries in Baghdad city. Blood samples were collected from 19 workers and 9 employees of the Scientific Research Council as control individuals, and chromosomes prepared from lymphocyte cultures were analyzed by standardized methods. Statistical analysis of the results gave significantly higher frequencies of chromatid and chromosome aberrations, particularly gaps, among the workers. No significant differences were observed in the incidence of chromosome aberrations in cells of smokers and non-smokers in both lead-exposed workers and controls. Therefore the observed increase in these aberrations was found to be associated mainly with exposure to lead oxides during the manufacture of the lead alloy grids and lead smelting.     

人参皂苷Rb_3对中国仓鼠肺细胞染色体畸变作用

目的研究人参皂苷Rb3对中国仓鼠肺细胞（CHL）染色体畸变作用。方法测定人参皂苷Rb3对CHL细胞的半数抑制浓度（IC50）,根据IC50设立不同剂量组,进行染色体畸变试验,分别观察人参皂苷Rb3接触CHL细胞6 h、24 h及加S9后6 h染色体的畸变情况,根据标准进行结果判定。结果染毒6 h、24 h及加S9后染毒6 h染色体畸变为阴性。结论人参皂苷Rb3不能引起CHL细胞染色体产生畸变作用。     

Fenvalerate-induced chromosome aberrations and sister chromatid exchanges in the bone marrow cells of mice in vivo

Fenvalerate, a synthetic pyrethroid insecticide, is commonly used in agriculture and other domestic applications due to its high insecticidal activity and low mammalian-, avian- and phyto-toxicities. However, the genotoxic effect of fenvalerate is highly equivocal. In the present study the genotoxic effects of fenvalerate was evaluated using structural chromosome aberration (CA) and sister chromatid exchange (SCE) assays in mice. Out of the three doses (5, 10 and 20 mg/kg) tested, statistically significant increase in CA was found following intra peritoneal (i.p.) treatment of 20 mg/kg of fenvalerate for 24 h (P<0.01) and 48 h (P<0.05) only. Neither the acute doses of 5 and 10 mg/kg, nor the sub-acute dose (5×4 mg/kg) of fenvalerate could induce any significant effect. All the three acute doses induced significant increase in the frequency of SCEs (P<0.01) in the bone marrow cells, which showed a significant dose-response correlation (r=0.9541, P<0.05). With certain reservations to possible impurities, from the present findings technical grade fenvalerate may be considered as a weak clastogen and a potent inducer of SCEs in mice.     

植物减数分裂染色体配对与染色体组分析的研究进展

简要介绍了植物减数分裂染色体配对研究.综述了减数分裂染色体配对研究在鉴定异源易位系、确定多倍体物种类型、分析物种间亲缘关系和物种的染色体组来源及探讨杂种不育的细胞遗传学机制等诸多方面的应用进展.分析了影响染色体配对的主要因素,如配对控制体系、遗传背景和外界环境条件等,并展望了染色体配对研究与其他技术结合在染色体组分析中的应用前景.     

Chromosome stability differs in cloned mouse embryos and derivative ES cells

The mechanisms that have evolved to maintain genome stability during cell cycle progression are challenged when a somatic cell nucleus is placed in a meiotic environment such as the ooplasm. Chromosomal spindle aberrations ensue in the majority of reconstructed oocytes within 2 h of transplantation, but it is not known if they recover or persist with the onset of embryonic divisions. We analyzed the chromosomal spindles and the karyotype of cumulus cell-derived mouse clones through the initial and hence most critical mitoses. Cloned embryos start out with less aneuploidy than fertilized embryos but surpass them after ES cell derivation, as measured by frequencies of chromosome trisomies and structural rearrangements. Despite the limited proportion of cloned mouse embryos that reach late gestation, a phenotypic mutation lacking a karyotypic mark was found in a newborn mouse cloned in 2002 and has been inherited since by its offspring. These data concur with a prevalent epigenetic, rather than genetic, basis for cloned embryo failure, but they also warn against the temptation to think that all conditions of clones are epigenetic and recover during gametogenesis. The cloning procedure is defenseless (no matter how technically refined) towards pre-existing or induced subchromosomal mutations that are below the experimental detection limit of the cytogenetic assay.     

Difference in types of radiation-induced structural chromosome aberrations and their incidences between Chinese and Syrian hamster spermatozoa

The effects of ionizing radiations on sperm chromosomes were studied in the Chinese hamster (Crisetulus griseus) and the Syrian (golden) hamster (Mesocrisetus auratus). Testes of mature male Chinese hamsters (CH) were irradiated with X-rays (0.91, 1.82 and 3.63 Gy) and γ-rays (1.10, 2.15, 2.95 and 4.01 Gy) at a single acute dosage, whereas the irradiation was done with lower doses of X-rays (0.45, 0.91 and 1.82 Gy) and γ-rays (0.49, 0.99 and 1.98 Gy) in mature male Syrian hamsters (SH), taking the higher radiosensitivity of this species into consideration. They were mated with normal females within 6 days of exposure. Sperm-derived chromosomes were analyzed in 1125 and 1966 fertilized ova of the CH and the SH, respectively. In both species, there was no great difference in the induction of structural chromosome aberrations between X-irradiated and γ-irradiated spermatozoa. Chromosome-type aberrations were predominantly induced. The incidence of breakage-type aberrations increased linearly, and that of exchange-type aberrations linear-quadratically with increase of dosage. A species-specific difference in chromosomal radiosensitivity of spermatozoa was clear. In spite of the same radiation dosage, the incidence of chromosomally abnormal spermatozoa in the SH was about twice as high as that in the CH (e.g., 27.0% vs. 14.7% at 0.91 Gy of X-rays). The incidences of breakage-type aberrations (69–89%) were far higher than those of exchange-type aberrations (11–31%) in the SH, while the disparity of the two incidences was much smaller in the CH (46–65% vs. 35–54%). Exchange-type aberrations consisted of both chromosome-type and chromatid-type in the SH, while almost all of them were of the chromosome-type in the CH. These results suggest that the DNA-repairing capacity of oocytes is much higher in the CH than in the SH. Moreover, it seems likely that radiation-induced sperm DNA damage is repaired with both pre-replication repair (excision repair) and post-replication repair systems in SH oocytes, whereas the excision repair system operate most exclusively in CH oocytes.     

Chromosome aberrations in lymphocytes and clastogenic factors in plasma detected in Belarus children 10 years after Chernobyl accident

In 1996, 10 years after Chernobyl accident, a cytogenetic analysis was carried out to assess whether chromosome aberrant cells (CA) were still detectable in the lymphocytes and clastogenic factors (CFs) were present in the plasma of children coming from Gomel (Belarus), one of the most heavily contaminated regions. Furthermore, the possible contribution of plasmatic CFs to the amount of CA was investigated. The presence of CA was examined in the lymphocytes from 29 thyroid tumour-affected children and 41 healthy children (local controls). Thirty healthy children living in Pisa (Italy) were enrolled in the study as additional controls from an uncontaminated area. No significant difference was observed between the two control groups, whereas a significantly increased frequency of CA was found in the tumour-affected children, as compared with Gomel and Pisa controls (χ²-test, p<0.001). However, when soil contamination level was taken into account, the chromosome type CA frequency observed in tumour-affected children coming from the more contaminated areas (>4 Ci/km²) resulted significantly higher than that in other children, either affected or not (p=0.003). The presence of CFs was analyzed on the plasma ultrafiltrate from 41 children. 7/10 (70%) plasma samples from tumour-affected children and 17/23 (74%) Gomel controls resulted to possess clastogenic activity irrespective of soil contamination levels. No activity was detected in the plasma of eight Pisa controls (0%). The difference between both Gomel groups and Pisa controls was highly significant (p=0.002). A borderline, but not statistically significant correlation (p=0.08) was observed between basal CA frequency and CF potency, which became significant (p=0.03) when only chromosome type of aberrations was considered. We conclude that, although the presence of CFs in the plasma of these children might be partly responsible of the cytogenetic effects observed, the main source of damage has considered to be do to the previous and/or continuous exposure to environmental radiocontaminants. Tumour-affected children may represent a subset of the population either more sensitive to clastogenic damage or exposed to higher levels of contaminants.     

Chromosome aberration and ploidy equilibrium of Vicia faba in tissue culture

Summary Different phytohormone concentrations induced different fequencies of various chromosome aberrations in calli of Vicia faba. NAA 10 ppm plus KT 2.5 ppm produced more haploids and NAA 30 ppm plus NAA 7.5 ppm produced more tetraploids and breakage. The relationship among the aberrations was analyzed. The hypothesis of ploidy equilibrium was established. The chromosome doubling rate and reduction rate of each treated group were calculated in relation to the observed data and the hypothesis. The frequency of tetraploids and breakage are correlated with each other. The frequency of total aberrations is linearly correlated with that of micronucleus formation. The regression equation is x=31.92+ 10.67 y.