Chromosomal anomalies

Zinc chloride induces chromosomal aberrations in human lymphocytes in vitro (Elinder 1986). A higher incidence of chromosome anomalies in leukocytes occurs among workers exposed to zinc (Elinder 1986), but these aberrations are likely due to other (unspecified) mutagenic factors in the work environment (Leonard and Gerber 1989). 

Results of studies in humans and animals suggest that sperm abnormalities, evidence of DNA damage such as chromosomal anomalies, and tests for liver and kidney dysfunction may serve as biomarkers of the effects of 1,2-dibromoethane (Ellingham et al. 1986 Heinrichs 1983 NTP 1982,... 

Although most human cancers are acquired diseases, all types may occur in heritable or nonheritablc forms, and heritabiUty may be associated with a dominant or recessive expression at a single locus, or with a constitutional chromosome anomaly. The changes associated with inherited predisposition to cancer must involve genetic alterations or mutational events at the sites of chromosome anomalies. There is now evidence for this in retinoblastomas. 

TABLE 7-4 Incidence of Chromosomal Anomalies Among the Newborn... 

Russell, L.B. Numerical sex-chromosome anomalies in mammals Their spontaneous occurrence and use in mutagenesis studies, pp. 55-91. In A. Hollaender,... 

Hartwich G, Schwanitz G, Becker J. 1969. Chromosome anomalies in a case of benzene leukaemia. German Medical Monthly 14 449-450. 

Proplolactone ie capable of oauelng chromosome anomalies reaulting in mutation in plants, - in bacteria and in yoastB. - These mntatione confer a resistance to antibiotics. 

Saha, A.K., and Chattopadhyay, S.C. 1977 Studies on the effect of atropine In the production of chromosome anomalies In spermatocytlc chromosomes of Indian acrldld grasshopper. Chromosome Information Service, No. 22 pp 3-5. 

Knuutlla, S., KHhkHnen, H., Wilska, H. 1976 Notable Chromosomal Anomalies in a Woman Receiving Drugs During the Period of Vlremla After Rubella Vaccination. Hered. 84 120-123. 

Cytogenetics is the oldest of the medical genetic sciences, but it did not become important clinically until 1959, when the presence of an extra copy of chromosome 21 (Trisomy 21) was first implicated in Down syndrome. Since then, many other chromosomal abnormalities have been directly associated with different diseases. By viewing metaphase cells with the light microscope, trained personnel can detect a broad range of numerical and structural chromosome anomalies that can then be correlated to specific diagnoses ranging from Down syndrome and Thrner syndrome to various types of cancer. 

Chromosome anomalies and aberrations can influence heredity. Most somatic cells of humans contain 23 pairs of chromosomes, with one member of each pair contributed by the sperm and the other contributed by the egg. When the process of sperm or egg cell production goes awry as a result of radiation damage, abnormal chromosome numbers (aneuploidy) can arise. Aneuploidy is a form of genetic instability. 

Pharmacon Chromosomal anomalies Chromosomal breaking Achromatic gaps... 

Genetics has already been incorporated into the care of children with cancer an example is the Philadelphia Chromosome, a chromosomal anomaly produced as a result of reciprocal translocation between chromosomes 9 and 22 [t(9 22)(q34 qll)] that is most commonly seen as a marker of chronic myeloid leukemia [50]. The presence of this chromosomal anomaly is associated with altered prognosis—and the need for different therapy—when seen in the context of acute lymphoblastic leukemia in childhood [51], An area of oncology care where genetics has not been widely used has been in the evaluation—and possibly prevention—of adverse drug reactions [52],... 

Conference on Leukocyte Chemistry and Morphology Correlated with Chromosome Anomalies. N. Y. Academy of Sciences, November 3-5, 1966. 

The answer is d. (Murray, pp 812—828. Scriver, pp 3—45. Sack, pp 57-84. Wilson, pp 123—148.) Mosaicism occurs when a chromosomal anomaly affects one of several precursor cells of an embryo or tissue. The two or more karyotypes that characterize the mosaic cells are separated by a slash in cytogenetic notation. The notation 47,XX,-I-2I denotes a cell line typical of a female with trisomy 21 (Down s syndrome), while 46,XX is the karyotype expected for a normal female. 

Radioactive Strontium. A slight increase in apparently lethal chromosomal anomalies (unspecified) was observed in the progeny of the Techa River population that was exposed to combined external gamma radiation and internal radiation from 90Sr and 137Cs between 1949 and 1956 (Kossenko et al. 1994). 

Radioactive Strontium. In the Techa River cohort, individuals who were exposed to high levels of radiostrontium as teenagers had a higher frequency of stable transformations than those who were adults at the time (Bauchinger et al. 1998) the differences were attributed to increased skeletal incorporation of radiostrontium in the young. The progeny of the exposed cohort showed an elevated incidence of adverse pregnancy outcomes (mortality from developmental anomalies, chromosomal anomalies, labor... 

These brightly colored RxFISH-painted chromosomes are both beautiful and useful in revealing chromosome anomalies and in comparing karyotypes of different species. [ Department of Clinical Cytogenetics, Addenbrookes Hospital/Photo Researchers, Inc.]... 

Grasshoppers injected intra-abdominally with relatively high concentrations of soluble copper showed a 1.6% frequency of chromosomal anomalies in meiotic cells of testes 24 h after injection however, no control data were presented. Copper-induced DNA strand breaks in rats (Rattus sp.) and chromosomal aberrations and sperm abnormalities in mice (Mus sp.) suggest that copper is a potential human mutagen. Copper salts affect chromosomes in vitro in the presence of hydrogen peroxide and ascorbic acid and can also increase the frequency of noncomplementary nucleotides in... 

Mutagenic effects of monofunctional alkylating chemicals in vivo have already yielded substantial results. Toxicity trials indicate that the Armenian hamster is two and a half times more sensitive than the mouse to ethyl methanesulfonate (Lavappa and Yerganian, 1969). With regard to induction of chromosomal anomalies, intraperitoneal administration of low doses (100 mg/kg) of ethyl methanesulfonate is sufficient to produce an overall incidence of 30% viable translocations in the male progeny. Furthermore, translocated chromosomes and bivalents can be accurately identified in terms of specific sites of breakage and reunion in both spermatogonia and spermatocytes (Table 2). Since the translocated F males are found in litters... 

Ethyl carbamate (urethan), another monofunctional alkylating agent, when administered intraperitoneally (100 mg/kg) will not have any noticeable effect on meiotic chromosomes. If the same dose is given to F2 male Armenian hamsters derived from grandsires treated with ethyl methane-sulfonate, totally different results are obtained—1 to 7 days after treatment there are no chromosome anomalies on day 8 the number of bivalents is reduced from 11 to ten and nine. In 80% of the spermatocytes ten bivalents can be encountered, and in about 10% of the spermatocytes nine bivalents are encountered. The reduction in the number of bivalents was due to associations of two and/or three bivalents. 

The highly specific medial breakage on the long arm of the X-chromo-some is the most impressive evidence of latent expression of chromosome anomalies. Thirty-five female-derived male progeny were treated with urethan as above and observed daily for 12 days. Two of the four males viewed on the 6th day following urethan treatment had the specific breakage... 

Electronmicroscopic analysis of the pachytene nuclei revealed no abnormalities of the synaptonemal complexes in either sex chromosomes or autosomes in all 30 analyzed spermatocytes from four control males (Table 2). Exposure to cat urine led to a significant increase in the number of males with chromosomal anomalies (3 out of 4 males Z2=4.80, p<0.01. Chi-square test). In 12.5% of spermatocytes (4 out of all 32 analyzed cells) abnormal SC configurations were found. (Z2=11.63, p<0.001 Chi-square test). The meiotic anomalies included terminal and interstitial autosomal asynapsis combined with nonhomologous pairing and sex chromosome dissociation (Table 2). 

About half of those spontaneous abortions have a recognizable (c)d o)genetic problem in the form of chromosomal anomalies that are big enough to see in a microscope with proper preparation and staining. The other half of them have had no readily diagnosable problem. Recent advances in DNA microarray technology now allow us to see sub-microscopic anomalies in the DNA of some of them, and even to find some of the single-base-pair mutations when we have a reasonable idea of what to look for. 

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