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PubMed1996

Cytogenetics of uncleaved oocytes and arrested zygotes in IVF programs.

PURPOSE: Cytogenetic studies of arrested oocytes and zygotes were used to understand in vitro fertilization (IVF) failures. METHODS: We investigated the cytogenetics (Giemsa banding and FISH) of 710 uncleaved oocytes and 94 arrested zygotes from 208 patients undergoing IVF procedures. RESULTS AND CONCLUSIONS: Of uncleaved oocytes without a polar body, 39% were judged cytogenetically abnormal (17% unbalanced predivision and 21.5% diploid). Of 575 oocytes with a polar body, 124 (21.5%) showed numerical or structural chromosome aberrations. In arrested zygotes, approximately equal cases were found with separate condensed haploid complements (no syngamy), nuclear asynchrony and pulverized DNA, and apparently cytogenetically normal zygotes arrested at mitosis. These data on chromosome abnormalities were also analyzed with respect to two ovarian stimulation protocols and to maternal age. Both ovarian stimulation protocols and to maternal age. Both ovarian stimulation protocols showed the same levels of chromosome abnormalities. Overall chromosome abnormalities and premature chromosome condensation were also unchanged with maternal age. These data illustrate the significance of chromosome aberrations in IVF failures.

Adult↗
PubMed1999

Chromosome aberrations in B-cell chronic lymphocytic leukemia: reassessment based on molecular cytogenetic analysis.

In B-cell chronic lymphocytic leukemia (B-CLL) clonal chromosome aberrations are detected in approximately 40-50% of tumors when using conventional chromosome banding analysis. Most studies find trisomy 12 to be the most frequent chromosome aberration, followed by structural aberrations of the long arm of chromosomes 13 and 14. Trisomy 12 and the "14q+" marker are associated with shorter survival times, while the patients with 13q abnormalities have a favorable outcome, similar to those with a normal karyotype. The development of molecular cytogenetic techniques has greatly improved our ability to detect chromosome aberrations in tumor cells. Using fluorescence in situ hybridization, chromosome aberrations can be detected not only in dividing cells but also in interphase nuclei, an approach referred to as interphase cytogenetics. The prevalence of specific aberrations in B-CLL is currently being reassessed by interphase cytogenetics. By far the most frequent abnormality are deletions involving chromosome band 13q14, followed by deletions of the genomic region 11q22.3-q23.1, trisomy 12, deletions of 6q21-q23, and deletions/mutations of the TP53 tumor suppressor gene at 17p13. The evaluation of the true incidence of these aberrations now provides the basis for more accurate correlations with clinical characteristics and outcome. Deletions/mutations of the TP53 gene have been shown to be associated with resistance to treatment and to be an independent marker for poor survival. 11q deletions have been associated with extensive nodal involvement, rapid disease progression, and short survival times. Whether trisomy 12, 13q14, and 6q deletions have a prognostic impact awaits further study. The application of these molecular cytogenetic techniques will also contribute to the identification of the pathogenetically relevant genes that are affected by the chromosome aberrations in B-CLL.

Animals↗
PubMedDate not supplied

Molecular cytogenetic analysis of B-cell chronic lymphocytic leukemia.

The genetic alterations underlying the pathogenesis of B-cell chronic lymphocytic leukemia (B-CLL) are difficult to assess. Cytogenetic studies are hindered by the low in vitro mitotic activity of the tumor cells and the limited resolution of chromosome banding. Molecular genetic analyses are hampered by nonclonal cells contained in the specimens and by the limited knowledge of candidate genes involved. As a complement to cytogenetic and molecular genetic techniques, fluorescence in situ hybridization (FISH) has proven powerful in the molecular cytogenetic analysis of B-CLL. FISH allows the detection of aberrations such as trisomies, deletions, and translocation breakpoints on the single cell level in dividing as well as non-dividing cells without the prerequisite of detailed physical maps or knowledge of involved genes. As detected by the interphase cytogenetic FISH approach, the most common chromosome abnormalities of B-CLL are deletions in band 13q14, followed by deletions in 11q22-q23, trisomy 12, deletions in 17p13, and deletions in 6q21. Abnormalities in 17p13 seem to involve the TP53 tumor suppressor gene, but as yet no candidate genes have been identified for the other frequent aberrations. Toward the identification of such genes by positional cloning, FISH can be applied for detailed aberration mapping at the molecular level. Furthermore, the accurate detection of chromosome aberrations in B-CLL by FISH provides a valid basis for the evaluation of their prognostic significance. Inactivation of TP53 in 17p13 and deletions in 11q22-q23 have already been shown to be among the most important independent prognostic factors. Genetic abnormalities may eventually provide biological parameters, allowing a risk assessment for individual patients at the time of diagnosis of this clinically heterogeneous disease.

Chromosome Aberrations↗
PubMed1998

Correlation between genetic and cytogenetic maps of the rat.

To correlate rat genetic linkage maps with cytogenetic maps, we localized 25 new cosmid-derived simple sequence length polymorphism (SSLP) markers and 14 existing genetic markers on cytogenetic bands of chromosomes, using fluorescence in situ hybridization (FISH). Next, a total of 58 anchor loci, consisting of the 39 new and 19 previously reported ones, were integrated into the genetic linkage maps. Since most of the new anchor loci were developed to be localized near the terminals of the genetic or cytogenetic maps for each chromosome, the orientation and coverage of the whole genetic linkage maps were determined or confirmed with respect to the cytogenetic maps. Thus, we provide here a new base for rat genetic maps.

Animals↗
PubMed1998

Neurofibromatosis pseudogene amplification underlies euchromatic cytogenetic duplications and triplications of proximal 15q.

Cytogenetically visible interstitial duplications of proximal 15q, which lack the Prader-Willi Angelman critical region (PWACR) frequently segregate in families without phenotypic effect, but the nature of the extra euchromatin has remained unclear. We used comparative genome hybridisation to confirm that the extra material in a cytogenetic triplication originated from proximal 15q. A PAC clone containing sequences specific for the type-1 neurofibromatosis (NF-1) pseudogenes, which map to 15q11.2, hybridised along the length of the enlarged region between the PWACR and the centromere. Computerised measurement of the fluorescent signal from the enlarged and normal chromosomes gave an average ratio of 9.85:1, consistent with amplification. In a second family, an amplified P1-4 signal co-segregated with a cytogenetic duplication and the average ratio between amplified and normal signals in the proband was 8.22:1. Ratios in noncarrier family members and control individuals were close to unity in most cases, but significantly greater than one in at least one instance. Our results provide a novel explanation for cytogenetic variation in 15q11.2. They also suggest that NF-1 pseudogene copy number may be polymorphic in the normal population, and that high copy numbers can produce G bands which do not reflect those of the normal constitutional karyotype.

Adolescent↗
PubMed2005

Conventional and molecular cytogenetic findings of myelodysplastic syndrome patients.

Myelodysplastic syndrome (MDS) involves myeloid cells of the bone marrow, which is important in progressive bone marrow insufficiency. Of all MDS patients, 40%-50% have at least one chromosomal rearrangement. Loss of specific chromosomal regions like 5q- and 7q- are usually the secondary cytogenetic abnormalities associated with MDS. In order to detect chromosome abnormalities associated with MDS, bone marrow samples from 26 patients diagnosed as MDS were obtained prior to chemotherapy. Both conventional cytogenetic analyses and fluorescence in situ hybridisation (FISH) methods were performed and locus-specific probes for 5q and 7q were used. Results obtained were compared. Twenty-one patients had normal karyotypes and four patients had abnormal karyotypes, while in one patient we could not obtain metaphases from cultures. Three patients with normal karyotypes revealed del (5q), two patients had del (7q) and one patient had monosomy (7). A total of 10 of 26 patients had chromosome changes visualised by either conventional or molecular cytogenetics (approximately 38.5%). Our results show that both methods are important in diagnosis and follow up of MDS patients. When used together, conventional cytogenetics and FISH detect clinically significant chromosome abnormalities in MDS patients.

Aged↗
PubMed2005

Integration of the cytogenetic and physical maps of chicken chromosome 17.

The chicken genome, like those of most avian species, contains numerous microchromosomes that cannot be distinguished by size alone. Unique properties attributed to the microchromosomes include high GC content and gene density, and an enhanced recombination rate. Previously, microchromosome GGA 17 was shown to align with the consensus genetic linkage group E41W17, and bacterial artificial chromosome (BAC) clones containing E41W17 markers were isolated and assigned on the physical BAC map as well as the recently assembled draft chicken genome sequence. For this study, these same BACS were utilized as probes for fluorescence in-situ hybridization (FISH) to develop the GGA 17 cytogenetic map. Here we detail the chromosome order of ten BAC DNAs, thereby deriving a cytogenetic map of GGA 17 that is simultaneously integrated with both the linkage map and genome sequence. The location of the FISH probes together with the morphological appearance of the chromosome suggested that GGA 17 is an acrocentric chromosome whose cytogenetic map orientation is reversed from that currently indicated by the linkage map and draft genome sequence. The reversed orientation and the centromere location of GGA 17 were confirmed experimentally by dual-colour FISH hybridization using terminal BACs and the centromere-specific CNM oligonucleotide as probes. An advantage of this cyto-genomic approach is the improved alignment of the sequence and linkage maps with cytogenetic features such as the centromere, telomeres, p and q arms, and staining patterns indicating GC versus AT content.

Animals↗
PubMed1986

Cytogenetic analysis of leukaemic cells in the dog. A report of 10 cases and a review of the literature.

Cytogenetic abnormalities were found in 9 of 10 leukaemic dogs. Important findings were aneuploidy, especially hyperdiploidy, extra-metacentric chromosomes, double minute chromosomes and tetraploidy. Six dogs had a normal chromosome modal number of 78, but 4 other dogs had modal numbers of 54, 81, 83 or 85 and 156. One to 16 extra-metacentric chromosomes were seen in cells from 5 dogs. Double minute chromosomes, which appear to be markers for neoplasia, were seen in one or more cells from 3 leukaemic dogs. Too few adequate, simultaneous studies were available to compare cytogenetic results from blood and bone marrow samples of leukaemic dogs. Extra-metacentric chromosomes and double minute chromosomes were not found in cells from the normal control dogs and cells with more than 78 chromosomes were rare. Specific chromosome changes were not associated with any of the various types of leukaemia and prognosis could not be predicted from the cytogenetic findings but, in general, the prognosis was poor. However, it does appear that many or most dogs with leukaemia have chromosomal abnormalities. With additional research and improvements in leukaemia therapy, cytogenetic studies of canine leukaemia may provide diagnostic and prognostic information.

Animals↗
PubMed1992

Cytogenetic and survival adaptive responses in G1 phase human lymphocytes.

Human lymphocytes from six donors were treated with 5 cGy of X-rays followed by 200 or 400 cGy in the first G1 phase after PHA stimulation, and assayed for cytogenetic aberrations and cell survival. Four donors showed cytogenetic adaptive responses with 400 cGy, and one with both 200 cGy and 400 cGy. Both exchanges and deletions were reduced, indicating that the cytogenetic adaptive response acts by restitution of chromosome breaks. Good correlations were found between nonaberrant cells and survival, although the former were often higher than the later, especially with the 400 cGy dose. In four of six donors, 5 cGy alone had significant effects on cell survival; however, this was independent of the 5 cGy effect on high-dose-induced responses. Two donors had survival adaptive responses with 5 + 200 cGy, while none were found with the 5 + 400 cGy treatment. The comparisons between the cytogenetic and survival responses suggests that a survival adaptive response will only be seen with a sufficient increase in nonaberrant cells. To date, adaptive responses to ionizing radiation have been reported to occur in G0, G1 and late S/early G2 human lymphocytes.

Adaptation, Physiological↗
PubMed1992

Griseofulvin-induced aneuploidy and meiotic delay in female mouse germ cells. II. Cytogenetic analysis of one-cell zygotes.

The effects of griseofulvin (GF) upon the first meiotic division of female mouse germ cells were evaluated by cytogenetic analysis of first-cleavage (1-Cl) zygotes. The present study is an extension of an investigation that began with the cytogenetic analysis of metaphase II (M II) oocytes. Different doses (200, 666, 1332, 2000 mg/kg) were tested by oral administration of GF to superovulated animals either at the time of human chorionic gonadotrophin (HCG) injection or 2 h post HCG. When GF was given at the time of HCG, significant dose-dependent increases of different types of cytogenetically abnormal cells were found. These included zygotes containing ostensibly female-derived M I or M II arrested chromosomes and polyploid zygotes. The total yields of these aberrations were 2.9, 4.3, 26.2, 60.6, and 64.1% for control, 200, 666, 1332, and 2000 mg/kg, respectively. The origin of these zygotes was attributed to the fertilization of oocytes that had been previously arrested at M I. No significant induction of hyperploidy was detected. Developmentally abnormal zygotes were still observed when GF was administered 2 h post HCG, although their frequencies were significantly lower than in the first series of experiments. The yields of developmentally abnormal zygotes were 49, 10.2, and 23.6% at 200, 666, and 2000 mg/kg. Additionally, a dose-dependent increase in the frequency of hyperploid zygotes was detected up to a maximum of 36.5% at 2000 mg/kg. These results confirm the cytogenetic observations from M II oocytes after GF treatment under the same experimental conditions; namely, a dramatic change in the oocyte target susceptibility to GF occurred within a short time period. Also, the present study demonstrated that most of GF-induced aneuploid oocytes were fertilized and reached first-cleavage metaphase.

Aneuploidy↗
PubMed1994

A re-evaluation of the cytogenetic effects of styrene.

Results from new chromosome studies in laboratory animals, comparative investigations of styrene metabolism and pharmacokinetics in humans and animals, and several recent cytogenetic surveys of styrene-exposed workers have necessitated a comprehensive re-evaluation of the chromosome-damaging effects of this chemical. Both styrene and its genotoxic metabolite, styrene oxide, can induce chromosome aberrations (CA) and sister chromatid exchanges (SCE) in vitro, but the chromosome-damaging ability of styrene is only manifested if test conditions favour its metabolic activation over inactivation. There is no convincing evidence of styrene clastogenicity in experimental animals. Styrene oxide is clastogenic only at lethal concentrations via i.p. injection in Chinese hamsters (but not via inhalation) or after oral treatment of mice, a route considered inappropriate for investigating the chromosome-damaging potential of inhaled styrene in man. Styrene and styrene oxide can induce SCE in animals at very high concentrations. Eighteen of 52 cytogenetic studies (CA, micronuclei, SCE) on peripheral blood lymphocytes of styrene workers have reported increases in chromosome damage. The positive findings are not compatible with the conclusion that styrene is responsible for the cytogenetic effects for the following reasons. (a) The positive or negative outcome of the various investigations bears no relationship to the degree of exposure of the workers. (b) There is no convincing evidence of a positive dose response relationship. (c) The relative induction of CA and SCE in worker studies are the opposite of observations of styrene effects in cultured lymphocytes and in laboratory animals. (d) The reports of chromosome-type exchanges in some studies of styrene workers is inconsistent with observations of styrene clastogenicity in cultured lymphocytes. (e) Reports of SCE induction in workers exposed to low concentrations of styrene are not compatible with results of animal inhalation studies, particularly in view of the differences in styrene metabolism and pharmacokinetics between humans and rodents. The increases in cytogenetic effects reported in some studies on styrene workers are probably attributable to the presence of other chromosome-damaging agents in the workplace and/or to inadequate investigations.

Animals↗
PubMed1991

Comparative mutagenicity testing of bropirimine, 3. Bropirimine does not induce cytogenetic damage in vivo in the rat but does produce micronuclei in the mouse.

Bropirimine is a biological response modifier (BRM) with potential antineoplastic and antiviral indications. Recent results have documented the negative findings in the Ames Salmonella assay, the in vitro UDS assay and the mouse lymphoma TK+/- assay as well as positive findings in the in vitro cytogenetic assay in CHO cells. Extensive mechanistic studies failed to establish the reason for positive findings in the in vitro cytogenetic assays. The data reported here cast doubt on the relevance of the in vitro cytogenetic results and suggest limited in vivo genotoxic potential. At doses as high as 150 mg/kg (i.p.) and 6.73 g/kg (p.o.), no evidence of chromosome aberration induction was observed in rat bone marrow cytogenetic assays. Consistent with these data, plasma and bone marrow tissue levels in similarly treated animals were well below those required for activity in the in vitro chromosome aberration assays. Positive results were obtained in the mouse micronucleus assay. However, the significance of these findings may be explained by markedly different pathways of metabolism in that species as compared to the rat. Hence, the findings in the mouse are of questionable relevance to human risk assessment. Exposure of humans to bropirimine, under therapeutically acceptable regimens is unlikely to constitute a genotoxic health hazard.

Animals↗
PubMed1985

Cytogenetic study in six Spanish patients with Burkitt's lymphoma.

A cytogenetic study carried out on affected tissues of six children with Burkitt's lymphoma revealed five cases with a typical translocation (8q-; 14q+) and one with a variant t(2p-; 8q+). Additional cytogenetic variations were present in three cases. One had two acrocentric marker chromosomes comprised of material from chromosome #1 (1q21----q44) translocated to the Y gonosome. The other two cases had a cytogenetic alteration of chromosome #12. Cytogenetic studies carried out systematically in Burkitt's lymphoma could be a great help in possibly establishing differences in the biologic and clinical aspects of cases presenting with the t(8;14) versus cases with variant translocations, as this would allow for classification of these patients into groups which, at present, cannot be differentiated using other diagnostic methods.

Adolescent↗
PubMed1986

Cytogenetic analysis of adult acute lymphoblastic leukemia including a Ph+ case surviving more than 5 years.

We have performed cytogenetic analysis on 25 consecutive adult patients with previously untreated acute lymphoblastic leukemia (ALL) who were subsequently treated with the same protocol at this institution. Ten of the 25 patients studied (40%) demonstrated karyotypic abnormalities. The most frequent abnormalities were hyperdiploidy (six patients) and presence of the Philadelphia (Ph) chromosome (three patients). Univariate analysis of 12 features identified only immunophenotype as differing between patients with abnormal and normal karyotype. The cells of patients with an abnormal karyotype were more often non-B, non-T and less often T cell in phenotype. One patient initially with Ph remains cytogenetically normal in complete remission 272 weeks post diagnosis. We confirm that cytogenetic abnormalities are frequent in adult ALL. The attainment of disease free survival in Ph-positive ALL of more than 5 years with persistently normal cytogenetics demonstrates that aggressive multimodal therapy can induce long-term remissions and possible cure of this usually unfavorable situation.

Adolescent↗
PubMed1987

Prognostic implication of cytogenetic findings in 106 patients with non-Hodgkin lymphoma.

The cytogenetic findings in samples from 106 patients with non-Hodgkin lymphomas (NHL), histopathologically classified according to the Kiel classification, have been correlated with survival time. Clonal chromosomal abnormalities were found in 60 patients, and only normal karyotypes in ten. The chromosome analysis of the remaining samples failed. The failures did not differ in survival compared with the cytogenetically successful cases, indicating that this group is not a prognostic entity within NHL. The cytogenetic findings were classified in six ways in order to evaluate the prognostic value of the cytogenetic pattern. Multivariate analysis demonstrated that presence of clonal chromosome abnormalities and the number of aberrations both were important prognostic factors independent of histopathology, whereas, the modal chromosome number, presence of translocations, or unidentified marker chromosomes were not. Some characteristic chromosome abnormalities were correlated with survival time: Patients with a 1p+ marker or +7 had a significantly shorter survival time than patients with normal karyotypes only (NN). Patients with +3, +12, 6q-, i(17q), and t(14;18)(q32;q21) did not differ significantly from the NN group.

Chromosome Aberrations↗
PubMed1989

Clinical-cytogenetic correlations in myelodysplasia (preleukemia).

Cytogenetic studies detected abnormalities in 107 (43%) of the 247 patients in this series. Some degree of overt clinical progression occurred in 55 patients (22%), this being 29% of those patients with cytogenetic abnormalities and 17% of those with normal chromosomes. The presence and complexity of a clonal cytogenetic abnormality correlated with shorter survival. In each clone category of a complexity classification (simple, complex, very complex), patients with some normal cells appeared to have better survival than those with none. In multiple regression analyses, the prognostic value of chromosomes was independent of (and second in importance to) the FAB type of myelodysplastic syndrome (MDS) whichever chromosome classification was used. Patients with refractory anemia (RA) had the lowest incidence of chromosome abnormalities and no cases were found to have only abnormal cells (AA). A greater proportion of patients with refractory anemia with an excess of blasts (RAEB) and RAEB in transformation (RAEB-t) had clonal abnormalities. Morphology alone is not at present able to distinguish between RA or refractory anemia with ringed sideroblasts and similar disorders that may not be MDS in the strict sense. Demonstration of a clonal cytogenetic abnormality remains a positive indication of the presence of the neoplastic nature of the disease.

Adult↗
PubMed1989

Genetically different cell subpopulations in hydatidiform moles. A study of three cases by RFLP, flow cytometric, cytogenetic, HLA, and morphologic analyses.

Most investigators find a good correlation between the morphologic and cytogenetic classification of hydatidiform moles (HM), but exceptions have been noted. We have examined three cases of HM, using chromosome marker analysis on cultured cells, human leukocyte antigen typing on cultured and uncultured tissue, and restriction fragment length polymorphism (RFLP) analysis and flow cytometry on uncultured cells. In one morphologically partial mole, only one cell population (triploid) was found and data obtained by the above-mentioned techniques were concordant. The other two moles, which were classified morphologically as complete, consisted of several cell subpopulations differing in DNA content. In both cases only one cell population was disclosed by cytogenetic investigation. In one case, the cytogenetic analysis indicated that the cultured cells were near triploid with paternal chromosomes exclusively, whereas RFLP analysis showed that maternal X chromosomal alleles were present in the mole. The present findings demonstrate that some HMs contain cellular subpopulations with differing DNA content. One explanation for discordance between cytogenetic and morphologic classification may thus be the detection of only one cell subpopulation when karyotyping.

Chromosome Aberrations↗
PubMed1989

Cytogenetic abnormalities in tumors of patients with von Hippel-Lindau disease.

Von Hippel-Lindau (VHL) disease is an autosomal dominant disorder that causes the development of benign and malignant tumors in several organ systems. Tumors causing significant morbidity include retinal angioma, cerebellar hemangioblastoma (CH), renal cell carcinoma (RCC), and pheochromocytoma (Pheo). Cytogenetic studies of tumors in VHL patients are rare. Cytogenetic findings in tumors from 12 patients with VHL disease, including four RCCs, three CHs, and five Pheos are presented. Three of the four RCC cases were abnormal. Monosomy 3 or a deletion of 3p was present in all three abnormal cases. Complete or partial trisomy of chromosome 5 was present in two cases. A deletion of 14q, trisomy 7, and a missing Y were each observed in one case. These findings indicate that a deletion of 3p may be a primary cytogenetic change in RCCs associated with VHL disease in addition to playing a role in sporadic RCC. Duplications of 5q and deletions of 14q may be important secondary changes in the progression of the malignant phenotype. No visible cytogenetic abnormalities were observed in the three CHs, or in four of the Pheos. One of the five Pheos was found to exhibit mosaic trisomy 7; its significance is unclear at the present time.

Adrenal Gland Neoplasms↗