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PubMedDate not supplied

[The interphase death of dividing cells. The relation of interphase death to cell energy requirements].

In experiments with irradiated cells of Chinese hamster and Ehrlich ascites tumor a study was made of the influence of energy provision on their interphase death rate. The presence of the uncoupler of respiration and oxidative phosphorylation--carbonyl cyanide-3-chlorophenylhydrazone--in a medium without glucose was shown to drastically increase the interphase death rate of cells of both types, whereas this effect was not observed in a medium with glucose.

Animals↗
PubMed1976

Laser UV microirradiation of interphase nuclei and post-treatment with caffeine. A new approach to establish the arrangement of interphase chromosomes.

Laser UV microirradiation of Chinese hamster interphase cells combined with caffeine post-treatment produced different patterns of chromosome damage in mitosis following irradiation of a small area of the nucleus that may be classified in three categories: I)intact metaphase figures, II)chromosome damage confined to a small area of the metaphase spread, III)mitotic figures with damage on all chromosomes. Category III might be the consequence of a non-localized distortion of nuclear metabolism. By contrast, category II may reflect localized DNA damage induced by microirradiation, which could not be efficiently repaired due to the effect of caffeine. If this interpretation is right, in metaphase figures of category II chromosome damage should occur only at the irradiation site. The effect might then be used to investigate neighbourhood relationships of individual chromosomes in the interphase nucleus.

Animals↗
PubMedDate not supplied

[The intercellular interactions in the interphase death of irradiated thymocytes. A study of the influence of different cells on thymocyte interphase death].

The influence of different cells on death and pycnosis of thymocyte nuclei after in vitro irradiation has been investigated. It has been shown that the removal from the thymocyte suspension of cells, having the activity of natural killers, medullar thymocytes, and macrophages, does not influence the radiation-induced damage to cortical thymocytes. The injury of exposed thymocytes decreases, however, after incubation them with nonirradiated thymocytes or cultured cells, the efficiency of the latter being dependent on the type of cells. The data obtained may indicate that the exposed thymocytes interact with each other and exchange some factors that promote their injury.

Animals↗
PubMed1991

Chromosome topology in mammalian interphase nuclei.

Since 1968, when Comings published the pioneering paper on "the rationale for an ordered arrangement of chromatin in the interphase nucleus," technical methods have progressed tremendously and improved our understanding of interphase organization. The existence of highly ordered organizational patterns of the cell nucleus appears to be beyond any doubt and it is difficult to escape the conclusion that interphase chromosome topology is important for the complex regulation of the many varied and interrelated nuclear processes. However, it is worth emphasizing that a universally valid principle of chromosome arrangement does not exist and, therefore, any generalization of interphase patterns can be misleading. The factors of order according to which the chromosomes are arranged inside the nucleus are manifold: (1) Individual chromosomes remain in spatially separated domains throughout interphase, preventing an intermingling of the decondensed euchromatin. (2) Chromosome regions that contain constitutive heterochromatin associate into larger chromocenters. (3) In most cell types direct associations between interphase domains of homologous chromosomes are not observed. In others homologous heterochromatic regions tend to be paired preferentially. (4) Interphase chromosomes do not float freely in the nucleoplasm; they are associated to varying degrees with the nuclear membrane and other components of the nuclear scaffold. The number of attachment sites for each chromosome to the nuclear membrane is relatively low. (5) The positions of centromeres (and pericentromeric heterochromatin) are nonrandom and characteristic of each cell type. Specific centromere movements occur during the cell cycle, during differentiation, and under certain pathophysiological conditions. (6) The telomeric chromosome ends are particularly prone to associate in certain somatic cell types and in meiotic prophase cells. (7) The arrangement of repetitive DNA families appears to determine a structural framework of the interphase nucleus. Different cell types of one organism can exhibit marked differences in their repetitive DNA framework, whereas cells that are in an identical differentiated state or an identical phase of the cell cycle often show comparable interphase patterns even in evolutionarily distant species. (8) The various steps of ribosome biogenesis take place in a precise fashion within a separate nuclear domain, the nucleolus. The topologically well-defined nucleolar substructures are required for rDNA transcription and pre-rRNA processing. (9) A compartmentalization of transcriptional and processing events is also evident in the rest of the nucleus. However, it is not yet known if the in situ sites of transcription and RNA processing for a particular (nonribosomal) gene or gene family are actually adjacent. (10) DNA replication is precisely spatiotemporally regulated within the nucleus. The replication domains are immobilized on the nuclear matrix.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1992

Relationship between interphase AgNOR distribution and nucleolar size in cancer cells.

We have studied the relationship between interphase nucleolar organizer region (NOR) distribution and nucleolar size in cancer cells at light-microscopical level. Thirteen cases of formalin-fixed bladder cancer and fifteen cases of methacarn-fixed tumours of different origin were used. Nucleoli of the former cases were stained by Phloxine B and of the latter by Toluidine Blue. Selective visualization of interphase NORs was obtained by carrying out the one-step silver staining reaction for AgNOR proteins (Ploton et al., 1986). The area occupied by Phloxine B- or Toluidine Blue-stained nucleoli and interphase silver-stained NORs was measured by means of an automated image analyser. Both in bladder cancers and in the other tumour lesions nucleolar and interphase AgNOR areas were linearly related (r = 0.95 and r = 0.96, respectively, P < 0.001). The close relationship between the area of nucleoli and that of silver-stained nucleolar structures was maintained even if the silver-staining procedure was prolonged beyond the optimal time length for selective interphase NOR staining. In the latter case, however, single interphase AgNORs were no longer visible within the nucleolar body which was, in fact, homogeneously stained. These data indicate that evaluation of the interphase AgNOR area has the same relevance, in tumour pathology, as whole nucleolar size measurement.

Cell Nucleolus↗
PubMed1985

Specific staining of human chromosomes in Chinese hamster x man hybrid cell lines demonstrates interphase chromosome territories.

In spite of Carl Rabl's (1885) and Theodor Boveri's (1909) early hypothesis that chromosomes occupy discrete territories or domains within the interphase nucleus, evidence in favor pf this hypothesis has been limited and indirect so far in higher plants and animals. The alternative possibility that the chromatin fiber of single chromosomes might be extended throughout the major part of even the whole interphase nucleus has been considered for many years. In the latter case, chromosomes would only exist as discrete chromatin bodies during mitosis but not during interphase. Both possibilities are compatible with Boveri's well established paradigm of chromosome individuality. Here we show that an active human X chromosome contained as the only human chromosome in a Chinese hamster x man hybrid cell line can be visualized both in metaphase plates and in interphase nuclei after in situ hybridization with either 3H- or biotin-labeled human genomic DNA. We demonstrate that this chromosome is organized as a distinct chromatin body throughout interphase. In addition, evidence for the territorial organization of human chromosomes is also presented for another hybrid cell line containing several autosomes and the human X chromosome. These findings are discussed in the context of our present knowledge of the organization and topography of interphase chromosomes. General applications of a strategy aimed at specific staining of individual chromosomes in experimental and clinical cytogenetics are briefly considered.

Animals↗
PubMed1991

Importance of interphase nucleolar organizer regions in tumor pathology.

The importance of the distribution of silver-stained nucleolar organizer regions (Ag-NORs) in interphase nuclei for diagnostic and prognostic purposes in tumor pathology has been reviewed. The available data demonstrated that interphase Ag-NOR evaluation may be of help in distinguishing malignant from hyperplastic or normal cells. On the other hand, there is increasing evidence that a relationship exists between the quantity of interphase Ag-NORs and the prognosis of malignant tumors: the greater the number of interphase Ag-NORs, the worse is the prognosis. This can be explained by the observation that the interphase Ag-NOR quantity is strictly related to the cell proliferation rate. The procedures used for the measurement of the interphase Ag-NOR quantity are also critically discussed.

Cell Division↗
PubMed1989

The proximity of DNA sequences in interphase cell nuclei is correlated to genomic distance and permits ordering of cosmids spanning 250 kilobase pairs.

The physical distance between DNA sequences in interphase nuclei was determined using eight cosmids containing fragments of the Chinese hamster genome that span 273 kb surrounding the dihydrofolate reductase (DHFR) gene. The distance between these sequences at the molecular level has been determined previously by restriction enzyme mapping (J.E. Looney and J.L. Hamlin, 1987, Mol. Cell Biol. 7: 569-577; C. Ma et al., 1988, Mol. Cell Biol. 8: 2316-2327). Fluorescence in situ hybridization was used to localize the DNA sequences in interphase nuclei of cells bearing only one copy of this genomic region. The distance between DNA sequences in interphase nuclei was correlated to molecular distance over a range of 25 to at least 250 kb. The observed relationship was such that genomic distance could be predicted to within 40 kb from interphase distance. The correct order of seven probes was derived from interphase distances measured for 19 pair-wise combinations of the probes. Measured distances between sequences approximately 200 kb apart indicate that the DNA is condensed 70- to 100-fold in hybridized nuclei relative to a linear DNA helix molecule. Cell lines with chromosome inversions were used to show that interphase distance increases with genomic distance in the 50-90 Mb range, but less steeply than in the 25-250 kb range.

Animals↗
PubMed1991

Interphase cytogenetic analysis detects minimal residual disease in a case of acute lymphoblastic leukemia and resolves the question of origin of relapse after allogeneic bone marrow transplantation.

We used in situ hybridization with a probe for the X chromosome to study interphase cells of bone marrow and peripheral blood specimens from a male patient with acute lymphoblastic leukemia characterized by hyperdiploidy, including trisomy X. In a posttreatment bone marrow specimen, which was interpreted as a regenerating bone marrow morphologically and which demonstrated a normal karyotype cytogenetically, trisomy X was found in 16 of 1,000 interphase cells. This finding indicated the presence of leukemic cells that were undetected by conventional morphologic and cytogenetic techniques (ie, minimal residual disease). Cytogenetic studies of a relapse specimen obtained after a sex-mismatched bone marrow transplant showed only a normal female karyotype in each of 40 metaphase cells, suggesting that the relapse occurred in donor cells. However, interphase analysis demonstrated trisomy X in more than 80% of interphase cells and indicated that the relapse was of the original clone and was not a transformation of donor cells. This case illustrates that interphase analysis can be useful as an adjunct to conventional cytogenetic analysis in the detection of minimal residual disease and in the analysis of interphase cells that are not accessible to routine cytogenetic methods. It also illustrates that previously reported instances of relapse of leukemia in donor cells could have been incorrect if supported by cytogenetic data alone.

Adult↗
PubMed1990

The mechanism of radiation-induced interphase death of lymphoid cells: a new hypothesis.

The interphase death of irradiated rat thymocytes depends on their concentration during postirradiation incubation. The kinetics of pycnosis and cell death determined with the trypan blue exclusion test in the samples with the highest cell concentration (1-2 x 10(7) cells/ml) is consistent with the data available in the literature, whereas the samples with the lowest concentration (2 x 10(5) cells/ml) undergo almost no pycnosis and death after irradiation with doses up to 50 Gy. On the basis of these results, we suggest a new mechanism of interphase death involving an interaction between irradiated thymocytes and the fraction of thymus cells possessing cytocidal activity. The observed correlation between the cytocidal activity and interphase death of thymocytes from animals of different ages favors our mechanism. It was found that the inhibitors which prevent the conjugation of killer cells and their targets do not influence interphase death, while the substances which block the secretion of cytotoxic factors or their action on the target membrane do protect from interphase death. Thus we suggest that the irradiation activates the killer cells to secrete some cytotoxic factors which induce pycnosis and interphase death of thymocytes.

Animals↗
PubMed1979

Visualization of the interphase chromosomes of Ornithogalum virens and Muntiacus muntjak.

A technique for visualizing "interphase chromosomes" was applied to nuclei of the angio-spermous plant, Ornithogalum virens (2 n = 6), and the male mammal, Muntiacus munjak (2 n = 7), in an attempt to correlate the numbers of "chromosomes" visible during interphase with the respective diploid chromosome numbers. The alterations in chromosome structure observed during G1, S, and G2 periods were comparable to those previously reported in Allium cepa and Chinese hamster (CHO line) cells [33], but for technical reasons it was only possible to make accurate counts of interphase chromosomes in the G1 nuclei of O. virens. In addition, from our observations of interphase chromosomes that were pulse-labelled with tritiated thymidine and a parallel study of premature chromosome condensation (PCC) using pulse-labelled M.muntjak cells, we conclude that, although chromatin decondensation may be required for DNA synthesis, extreme chromatin decondensation can occur in the absence of DNA synthesis. Generally a morphological description of alterations in chromatin during interphase only roughly parallels the G1, S, and G2 phases defined by autoradiography following incorporation of tritiated thymidine. We suggest that both methods are valid through different ways of describing interphase.

Animals↗
PubMed1977

Different sensitivity of DNA in situ in interphase and metaphase chromatin to heat denaturation.

Heat denaturation of DNA in situ, in unbroken cells, was studied in relation to the cell cycle. DNA in metaphase cells denatured at lower temperatures (8 degrees-10 degrees C lower) than DNA in interphase cells. Among interphase cells, small differences between G1, S, and G2 cells were observed at temperatures above 90 degrees C. The difference between metaphase and interphase cells increased after short pretreatment with formaldehyde, decreased when cells were heated in the presence of 1 mM MgCl2, and was abolished by cell pretreatment with 0.5 N HCl. The results suggest that acid-soluble constituents of chromatin confer local stability to DNA and that the degree of stabilization is lower in metaphase chromosomes than in interphase nuclei. These in situ results remain in contrast to the published data showing no difference in DNA denaturation in chromatin isolated from interphase and metaphase cells. It is likely that factors exist which influence the stability of DNA in situ are associated with the super-structural organization of chromatin in intact nuclei and which are lost during chromatin isolation and solubilization. Since DNA denaturation is assayed after cell cooling, there is also a possibility that the extent of denatured DNA may be influenced by some factors that control strand separation and DNA reassociation. The different stainability of interphase vs. metaphase cells, based on the difference in stability of DNA, offers a method for determining mitotic indices by flow cytofluorometry, and a possible new parameter for sorting cells in metaphase.

Cell Division↗
PubMed1991

Mapping of human chromosome Xq28 by two-color fluorescence in situ hybridization of DNA sequences to interphase cell nuclei.

We have used the proximity of probe hybridization sites in interphase chromatin to derive the order of DNA sequences in a 2-3-Mbp region of human chromosome Xq28. The map generated bridges the results of genetic and pulsed-field gel electrophoresis mapping to produce a more complete map of Xq28 than possible with either of these other techniques alone. Two-color fluorescence in situ hybridization (FISH) was used to detect the positions of two or more probes in G1 male interphase nuclei. We show that cosmids that are 50 kbp to 2-3 Mbp apart can be ordered rapidly with two alternative approaches: (1) by comparing the average measured distance between two probes and (2) simply by scoring the order of red and green fluorescent dots after detection of three or more probes with two fluorochromes. The validity of these approaches is demonstrated using five cosmids from a region spanning approximately 800 kbp that includes the factor VIII (F8), glucose-6-phosphate dehydrogenase (G6PD), and color-vision pigment (CV) genes. The cosmid map derived from interphase mapping is consistent with the map determined by restriction-fragment analysis. The two interphase mapping approaches were then used (1) to orient the F8/CV cluster relative to two markers, c1A1 and st14c, which we show by metaphase mapping to be proximal to the F8/CV cluster, (2) to position st14c (DXS52) between c1A1 and F8, and (3) to orient the CV gene cluster relative to G6PD by using two CV-flanking cosmids, 18b41 and fr7. The probe order in Xq28 derived from interphase proximity is cen-c1A1-st14c-5'F8 (p624-p542-p625)-G6PD-18b41-3' green-green-red-fr7-tel. We also show that, to determine their order by using metaphase chromosomes, sequences must be at least 1 Mbp apart, an order of magnitude greater than required in interphase chromatin. The data show that FISH mapping is a simple way to order sequences separated by greater than or equal to 50 kbp for the construction of long-range maps of mammalian genomes.

Chromosome Mapping↗
PubMed1990

Detection of monosomy 7 in interphase cells of patients with myeloid disorders.

Six patients, five with acute myeloid leukemia (AML) and one with a myelodysplastic syndrome (MDS), were found to have monosomy 7 by conventional cytogenetics at diagnosis. Repetitive DNA sequences from the heterochromatic region of human chromosomes 1 and 7 were used as probes for in situ hybridization experiments on interphase cells of these patients. A double hybridization protocol was used to reveal the particular chromosomes as distinct spots or clusters of signals within interphase nuclei. The chromosome 1 sequence served as an internal control. Simultaneous detection of the sequences showed the presence of two normal number 1 chromosomes and a missing 7 chromosome from individual cells. While cytogenetic preparations showed only -7 metaphases in 3 AML and 1 MDS patients, in situ hybridization of interphase cells showed many normal cells as well as the presence of -7 in fully mature granulocytes. One AML patient studied in remission showed only normal metaphases yet had 9% interphase cells with a missing 7 and relapsed within 3 months. We conclude that examination of interphase cells by in situ hybridization provides clinically useful data since every cell including mature granulocytes can be examined, the lineage of a cell can be determined, and efficacy of differentiation therapy can be evaluated.

Chromosome Deletion↗
PubMed1987

The blocked pinocytic activity of mitotic cells is restored in mitotic-interphase hybrids.

During mitosis there is an abrupt inhibition of a wide range of membrane functions, including fluid-phase and adsorptive pinocytosis. We have used cell hybrids formed between mitotic and interphase cells to approach the mechanism of this inhibition. We report that fluid pinocytosis is reactivated in the mitotic partner of hybrids formed between mitotic and interphase Chinese hamster ovary (CHO) cells. It thus appears that the interphase cell provides some necessary element(s) for membrane activity during mitosis. This dominance of interphase membrane properties stands in contrast with earlier evidence that mitotic nuclear properties dominate in similar mitotic-interphase hybrids.

Animals↗
PubMed1992

Longitudinal cytogenetic study of metaphase and interphase cells in childhood monosomy 7 syndrome.

A 15-year-old male with myelodysplastic syndrome (MDS) characterized by monosomy 7 was cytogenetically evaluated by metaphase karyotyping and fluorescence in situ hybridization (FISH) of interphase cells at six different points during the course of his disease. At diagnosis, there was complete agreement between metaphase and interphase findings. Interphase analysis alone provided important cytogenetic information on the first specimens received following intensive combination chemotherapy and bone marrow transplantation where metaphase analyses were uninformative. The detection of a minor post-treatment monosomy 7 population by interphase but not metaphase studies may have identified minimal residual disease prior to recurrence of MDS. From this longitudinal study, it is concluded that metaphase and interphase cytogenetic analyses form complementary approaches and that use of both provides greater analytical power when appropriate chromosome markers are available.

Adolescent↗