Chromatid-type aberrations

Data from in vivo (intraperitoneal) exposures of mice to aluminum chloride also indicate that this compound is clastogenic. Mice were injected intraperitoneally with 0.01, 0.05, or 0.1 molar aluminum chloride, and bone marrow cells were examined for chromosomal aberrations. There was a significant increase in chromatid-type aberrations over the controls, and these occurred in a nonrandom distribution over the chromosome complement (Manna and Das 1972). No dose-response relationship could be demonstrated, although the highest dose of aluminum chloride did produce the greatest number of aberrations. These data are supported by in vitro studies that show that aluminum chloride causes cross-... 

Chromatid—type aberration The damage expressed as breakage of single chromatids at the same locus. 

Chromosome-type aberrations are induced when a compound acts in the Gi phase of the cell cycle. Chromatid-type aberrations are induced when a chemical acts in the S or G2 phase of the cell cycle. 

Chromatid-type aberrations are believed to be induced by chemicals. In occupational monitoring it is very important to pay attention to this type of aberration. Some percentile values of chromatid deletions (without gaps) were collected and found by different authors (Table 15.7). A 2-fold difference exists between our data and that of others (0.44 vj... 

When the unit of breakage is the single chromatid, the aberration is said to be of the chromatid type. Chromatid-type aberrations are formed in the S and Gg stages of interphase. Chemicals which induce delayed effects (e.g., alkylating agents, maleic hydrazide) produce aberrations exclusively of the chromatid type. 

It is well known that irradiation induces G2-block. Kihlman et al. (1982) interpreted the potentiation of induced chromatid-type aberrations by caffeine on the... 

Kihlman, B. A., Hansson, K., Palitti, F., Andersson, H. C., and Hartley-Asp, B., 1982, Potentiation of induced chromatid-type aberrations by hydroxyurea and caffeine in G2, Prog. Mutat. Res. 4 11-24. 

Acid Ester Diamide Endoxan Cytoxan. Cyclophosphamide produces mainly chromatid-type aberrations in small mammals and in human lymphocytes. 102-108) it also induces dominant lethals in premeiotic and in postmeiotic male germ cells. 8 09,110)... 

The nucleus of all eucariotic cells contains the carrier of the genetic information in the chromosomes. It is possible to visualize the chromosomes and analyze their number and pattern during a special period of cell division (the metaphase). Alterations from their normal shapes are observed as structural chromosome aberrations. These are chromosome type aberrations (terminal and interstitial deletions, dicentrics and rings), chromatid aberrations (gaps, breaks and exchanges) and sister chromatid exchanges. Spontanous frequencies of such chromosome... 

Stmctural chromosome aberrations may be of two types, chromosome or chromatid. A chromo-some-type aberration is a stmctural chromosome damage expressed as breakage, or breakage and... 

Chromosome-type aberrations are structural chromosome damages expressed as breakage, or breakage and reunion, of both chromatids at an identical site. 

The induction of structural chromosome aberrations is classified in two types, chromosome or chromatid aberrations. The majority of induced aberrations are of the chromatid-type, but chromosome-type aberrations also occur. Chromosomal mutations and related events are the cause of many human genetic diseases and there is evidence that chromosomal mutations and related events are involved in cancer development. 

For practical purposes, the aberrations may be divided into three main types, viz, subchromatid-, chromatid-, and chromosome-type aberrations. 

In an aberration of the chromosome type, the two chromatids of a chromosome are broken or exchanged at the same loci. The chromosome-type aberration is believed to be induced in G, i.e., before duplication when the chromosomes are still single. It is produced by ionizing radiation and probably by chemicals such as streptonigrin (Kihlman, 1964 Kihlman and Odmark, 1965), phleomycin (Mattingly, 1967 Kihlman et al, 1967), and 8-ethoxycaffeine (Scott and Evans, 1964 Kihlman and Odmark, 1965). 

CldUrd does not induce chromosomal aberrations when cells are grown for only 12 h in the analogue [9]. However, incubation for 24 h in medium containing 100% CldUrd results in numerous aberrations, which are all of the chromatid type (Table 2). Treatment with a low dose of 3AB (1 xaM) increases this frequency. At 10 mAf the mitotic index is drastically decreased and less aberrations are observed. 

In nickel refinery workers exposed to nickel chloride and nickel sulphate, only an increase in chromatide gaps (a doubtful type of structural aberrations) was observed [449]. By contrast, there was no increase of the mean sister chromatide exchange value in the group of nickel workers, as compared with the control group. 

The classification and nomenclature of the International System for Human Cytogenetic Nomenclature (ISCN, 1985) as applied to acquired chromosome aberrations is recommended. Score sheets giving the slide code, microscope scorer s name, date, cell number, number of chromosomes and aberration types should be used. These should include chromatid and chromosome gaps, deletions, exchanges and others. A space for the vernier reading for comments and a diagram of the aberration should be available. 

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