Forty-eight new cases with infertility due to balanced chromosomal rearrangements: detailed molecular cytogenetic analysis of the 90 involved breakpoints.

A molecular cytogenetic study was performed on 48 infertile patients who were identified as carriers of balanced translocations (40 cases), inversions (6 cases) or insertions (2 cases) by means of banding cytogenetics. Cases with a Robertsonian translocation or pericentric inversion 2 or 9 were not included. In summary, 100 break-events occurred in these patients, and 90 different chromosomal regions were involved. Thus, this study confirmed the presence of abnormal karyotypes in a subgroup of patients seeking infertility treatment. Breaks were demonstrated to appear preferentially in GTG-light bands in these patients. Furthermore, the observed breakpoints were associated with genomic regions prone to instability due to the presence of segmental duplications. Nonetheless, further detailed molecular analysis will be necessary in the future to characterize the mechanisms and genetic basis for this phenomenon.

Maternal insertion of 18q11.2-q12.2 in 18p11.3 of the same chromosome analysed by microdissection and multicolour banding (MCB).

OBJECTIVES: Different aberrations in one chromosome 18 were prenatally detected during each of three different pregnancies of a healthy woman. Routine cytogenetic analysis revealed a morphologically altered maternal chromosome 18 as well. The purpose of the current study was to characterize these cytogenetic changes in detail and thus to clarify the reason for the recurrent appearance of morphologically altered chromosomes 18 in this family. METHODS: As GTG banding did not allow resolution of the kind of aberrations present in these four cases, the following molecular cytogenetic approaches were used: microdissection combined with reverse painting and multicolour banding (MCB) analysis using a chromosome 18 specific probe set. RESULTS: Molecular cytogenetic approaches revealed that fetus 1 had a derivative chromosome del(18)(q11.2q12.2), fetus 2 and the mother had the identical derivative chromosomes ins(18)(pterp11.32::q12.2q11.2::p11.32q11.2::q12.3qter) and fetus 3 had a dup(11.2q12.2). CONCLUSION: Partial monosomy in fetus 1 and partial trisomy in fetus 3 can be explained by crossing over events during maternal meiosis.

Inflammation markers in the serum of salt miners.

The inflammation markers alpha-1-antitrypsin (AAT), Clara cell protein (CC-16), soluble interleukin-2-receptor (IL-R) and the soluble adhesion molecule E-selectin, the intercellular adhesion molecule (ICAM-1) and the vascular adhesion molecule (VCAM-1) were determined in the serum of 195 salt-exposed miners to analyse dose-response relationships between markers and potash dust. Alpha-1-antitrypsin, Clara-cell protein, IL2-R, E-selectin and VCAM-1 were not changed by salt exposure, however the ICAM-1 level in the serum fell slightly as the salt exposure increased. This effect was strongest in the group of smokers, still visible in the group of ex-smokers, no effect was seen in non-smokers. Markers, with the exception of VCAM-1, were influenced by tobacco exposure. Since markers were not elevated in relation to salt dust exposure, the results do not support an inflammatory effect of potash dust on the respiratory system.

Cytogenetic studies in lymphocytes of patients with rectal cancer.

Spontaneous and clastogen-induced chromosomal instability in a high-risk group (i.e, 33 patients with rectal carcinomas) was investigated using peripheral blood lymphocytes as target cells. In addition to the analysis of spontaneous and clastogen-induced chromosome aberrations, this study also included classical karyotype analysis and scoring of sister chromatid exchanges (SCE) in some of the patients. Diepoxybutane (DEB), 4-nitroquinoline-1-oxide (NQO), and bleomycin were used as standard clastogens. Lymphocytes of healthy control individuals were studied in parallel with each cancer patient. While only slight but significant differences could be detected of the average spontaneous, DEB- and bleomycin (G2)-induced chromosome breakage between patient and control lymphocytes, individual patients and two of the control individuals showed a more distinct increase in the frequency of the studied end points. These increases were documented by a variegated mosaicism of karyotypic changes and by an increased breakage rate induced by the clastogens. Neither the bleomycin-exposure in the G1 phase nor SCE was capable of detecting differences between the patients and controls. Of particular interest in the sense of high-risk individuals were seven patients and two control persons whose lymphocytes exhibited increased chromosomal sensitivity under more than one of the studied experimental conditions.

Chromosome and oncogene studies in human rectal and colon carcinomas.

Cytogenetic examinations of 48 rectal and 17 colon carcinomas and analyses of proto-oncogene activation on 67 of the former and 8 of the latter tumors were performed. Besides a general considerable heterogeneity of chromosome counts, some chromosomes were found to contribute non-randomly to hypersomies (# 2, 3, 7, 9, 19, 20 and 6) and to hyposomies (# 14, 15, Y, 21, and 18) in this material. Chromosomal markers non-randomly involved breakpoint clusters on 17p11, 13q11, 7p, 1p11, and 1p36 and on the centromeric regions of chromosomes 1, 8, 14, 15 and 21. Cytogenetic equivalents of gene amplification ("double minutes") were present in only rather small cell fractions (less than 20%) of 50% of the studied tumors. Using a cDNA technique and a battery of respective probes, proto-oncogene overexpression was screened for in the tumor samples, but also in 24 samples of inconspicuous mucosae of tumor patients and in two mucosae of healthy individuals. Simultaneous overexpression of several proto-oncogenes was the most characteristic finding in the tumor cells. However several of the mucosa samples obtained from tumor patients also just exhibited clear signals of proto-oncogene overexpression, which were not found in epithelial cells from non-tumor patients.

Changes in the proliferation of human lymphocytes induced by several cytostatics and revealed by the premature chromosome condensation technique.

Premature chromosome condensation was induced by cell fusion in stimulated human lymphocytes treated with different cytostatics. Changes in the proportion of the cell-cycle stages were investigated after 72 h of culture. Although it has been reported that some agents which induce severe DNA damage accumulate cells in G2, our results have shown some differences in the modes of action of the different tested chemicals. These variations could be due to several factors like mechanisms of action of the drugs, sensitivity of lymphocyte subpopulations to the cytostatics, inter- and intra-individual variability in the response of donors.

Establishment and characterization of a granulocyte-macrophage colony-stimulating factor-dependent human myeloid cell line.

A new human myeloid cell line has been established recently from the bone marrow cells of a patient with chronic myelogenous leukemia in blast crisis. The active proliferation and survival of the cells in RPMI 1640 medium containing fetal calf serum are clearly dependent on the presence of either natural or recombinant human granulocyte-macrophage colony-stimulating factor (rhGM-CSF). Despite permanent culturing in rhGM-CSF (100 U/mL), the cells do not differentiate and bear the myelomonocytic surface markers CD34, CD13, CD36, as well as HLA-DR, but not CD3, CD7, CD10, CD11b, CD14, CD20, or CD42b. The predominant karyotype, apart from tetraploidy in several cells, is 45, XX, -9, -17, -19, -22, 7p-, 9q+ (der t[9;22]), der (13q), with three additional marker chromosomes, from which one was observed in the patient's leukemic cells. On BglII-digested DNA, Southern blot analysis with bcr 5' as the probe detected two additional hybridizing restriction fragments of 8.6 and 11.0 kilobase pairs.

[Chromosome mutagenicity of a 193 nm Excimer laser]. / Untersuchungen zur Chromosomenmutagenität eines 193-nm-Excimerlasers.

Considering the fundamental role somatic mutations play in carcinogenesis, inducing mutations by any form of therapy should be avoided as far as possible. The mutagenicity of UV irradiation in the wavelength range of 248 to 310 nm is well established. The data on shorter wavelengths, e.g. 193 nm, however, are so far not clear-cut. Therefore, the potential chromosome-damaging effect of a 193 nm excimer laser was examined in the present study. Cultures of primary human fibroblasts and the Chinese hamster cell line CHO were the object of examinations. The in situ preparation technique used allowed detection of a locally limited clastogenic (chromosome damaging) effect in the neighborhood of the irradiated area. A slight increase in the frequency of chromosome aberrations could be observed in the area close to the laser-exposed field, which was attributed to the fluorescence generated by the laser under the given experimental conditions. Quantitative comparison with the data obtained from experiments with 254 nm irradiation from a UV lamp or exposure to 248 nm excimer laser-pulse irradiation, however, made the former activity appear somewhat insignificant. If one considers the practical aspects of the new laser surgery, the chromosome-damaging effect of the 193 nm pulse laser seems to be negligible.

The activity of bleomycin and modifiers of its clastogenic effect on the interphase chromatin of Indian muntjak fibroblasts.

Premature chromosome condensation was induced in Indian muntjak fibroblasts after exposure of the cells to bleomycin. Further experiments were devoted to the interaction of anticlastogens and a repair inhibitor, streptovitacin A. Chromosomal aberrations due to bleomycin treatment were S-phase-independently visible in the G1 and G2 phase of the cell cycle. For premature chromosome condensation experiments, a 100-fold lower concentration of the mutagen produced a similar extent of chromosome damage as in metaphase studies. Additional exposure to the anticlastogens beta-aminoethylisothiouronium or N-acetylcysteine revealed differences between corresponding interphase and metaphase effects and between different exposure conditions. Streptovitacin A, known as an inhibitor of protein synthesis, acted like an anticlastogen in the G2 phase of the cell cycle. Our studies show that the premature chromosome condensation technique offers various qualitative insights into primary processes of mutagenicity and antimutagenicity, but requires further improvement and careful choice of the cell system for study.

Induction by chemical clastogens of aberrations in prematurely condensed interphase chromatin of Chinese hamster ovary cells.

The clastogenic activities of diepoxybutane and bleomycin were comparatively studied on prematurely condensed interphase chromatin and metaphase chromosomes of Chinese hamster ovary cells. The yield of chromosomal aberrations was distinctly higher in G2-premature chromosome condensation as compared to metaphase. Most notably, the clastogenic activity of bleomycin was visible in premature chromosome condensation after application of much lower final concentrations than necessary for induction of chromosome aberrations in metaphase. In addition, the different mechanisms of action of both clastogens were reflected by the aberration yield in G1 and G2 immediately after exposure. While bleomycin induced aberrations throughout all stages of interphase, diepoxybutane did not induce aberrations in G1 or G2. Though certainly not a routine system for genotoxicity testing, premature chromosome condensation analyses provide a powerful opportunity to demonstrate relationships between DNA damage and repair, and the production of chromosomal changes at the site of their formation.

Early T cell differentiated chronic myeloid leukemia blast crisis with rearrangement of the breakpoint cluster region but not of the T cell receptor beta chain genes.

Early T cell differentiation is described in a case of Philadelphia chromosome-positive chronic myeloid leukemia (CML) in blast crisis, supporting multi-lineage differentiation potential of CML precursor cells. In the absence of myeloid markers, strong positivity for terminal deoxynucleotidyl transferase (TdT) and reactivity with T cell antibody 3A1, but lack of more mature T cell antigens, provided evidence for immature T cell differentiation. Molecular analysis of the breakpoint cluster region (bcr) in chromosome 22 revealed a rearrangement and thus confirmed the CML origin of the early T cell blasts. T cell receptor beta chain sequences were found in germline configuration and therefore suggest a very immature stage of T cell differentiation in the CML blasts.