Library

X
feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    Electronic Resource
    Electronic Resource
    Differential spiralization along mammalian mitotic chromosomes (1972)
    Springer
    Chromosoma 38 (1972), S. 341-365 
    Details
    ISSN: 1432-0886
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract Morphology of chromosomes replicating in the presence of 5-bromodeoxyuridine was studied using long-term cultures of Chinese hamster cells (line Blld-ii-FAF28). The cytological effect of the analog administered in various concentrations, at different stages of the S period, and during one and two successive mitotic cycles was studied. — The main cytological manifestation of the BUdR action consisted in spiralization delay of certain chromosome regions. The degree of the delay was dependent on the time interval between the introduction of the agent and mitosis, as well as on the agent's concentration. With prolongation of the interval, the spiralization delay diminished and disappeared being therefore always observable only in late replicating chromosome regions. Increased concentration of BUdR (in the range of 25 to 400 μg/ml) produced enhancement of the delay of chromosome spiralization. — After two successive reproduction cycles in the presence of BUdR, a great number of metaphases contained chromosomes the sister chromatids of which showed unequal spiralization delay. Autoradiography of 3H-BUdR distribution showed that the sister chromatid with a more pronounced underspiralization corresponds to the chromatid incorporating BUdR into both strands of the DNA molecule. — Mechanisms of the effect observed, as well as chemical influence on chromosome spiralization as a usefull tool of displaying linear chromosome differentiation, are discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00320156
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    Differential spiralization along mammalian mitotic chromosomes (1974)
    Springer
    Chromosoma 44 (1974), S. 343-359 
    Details
    ISSN: 1432-0886
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract The morphology of human metaphase chromosomes of peripheral blood lymphocytes taken from normal persons of both sexes and cultured at the final stages of the S-period in the presence of 5-bromodeoxyuridine (BUdR), or 5-bromodeoxycytidine (BCdR) was studied. It was observed that the chromosomes of the complement were capable of responsing to the treatment with analogs by the appearance of extended segments along their length. The pattern of segmentation was constant and specific for a given chromosome, serving as a basis for its identification, and appeared to be similar for both analogs. — Autoradiography of such chromosomes performed with 3H-thymidine (3H-TdR), 3H-deoxycytidine (3H-CdR), and 3H-BUdR showed that the extended chromosomal segments are late replicating. In accordance with this correlation, the most regular and distinctive segmentation was observed in chromosomes having large late replicating regions, such as Nos. 4, 6, 9, 13, 16, X, and Y. — A comparative analysis of the BUdR-induced differential spiralization pattern and banding pattern obtained with the G-staining technique was carried out. A good correspondence between the extended segments and Giemsa-positive bands was found. The data are discussed in relation to the mechanism of differential staining of metaphase chromosomes.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00284894
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    Reversible differential decondensation of unfixed Chinese hamster chromosomes induced by change in calcium ion concentration of the medium (1982)
    Springer
    Chromosoma 84 (1982), S. 729-736 
    Details
    ISSN: 1432-0886
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract Differential decondensation of isolated unfixed Chinese hamster metaphase chromosomes was obtained by decreasing the calcium ion concentration in the surrounding medium. A banded appearance of the swollen chromosomes could be observed either directly by phase contrast microscopy or after glutaraldehyde fixation and staining. There was a gradual transition from homogeneously dense to banded and finally to extensively decondensed chromosomes. The patterns induced at different stages were similar to those observed on fixed chromosomes after standard banding procedures (i.e., G-, C-, Cd−, Ag-NOR-staining). Chromosome decondensation could be reversed by the addition of calcium ions to the medium. Ca++-dependent reversible differential chromosome decondensation was not observed if the chromosomes were previously treated with 0.35 M NaCl. Chromosome regions which had incorporated BrdU into their DNA were more resistant to a decrease in calcium ion concentration than BrdU non-substituted regions.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00286337
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    Possible evidence for the observation of noncompact (nonbaryonic) gravitational microlenses (“neutralino stars”) (2000)
    Springer
    Physics of atomic nuclei 63 (2000), S. 1042-1045 
    Details
    ISSN: 1063-7788
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract The microlensing of distant stars by noncompact objects such as neutralino stars is considered. Recently, Gurevich and Zybin considered the objects as microlenses. Using a nonsingular density distribution, we analyze microlensing by noncompact objects. We obtain analytic solutions to the gravitational-lens equation and an analytic expression for the amplification factor of the gravitational lens. We show that, on the basis of a model of microlensing by noncompact objects, it is possible to interpret microlensing-event candidates having two typical maxima of light curves which are usually interpreted as binary microlenses.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1134/1.855746
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 5
    Electronic Resource
    Electronic Resource
    Microlensing by noncompact objects (1996)
    Springer
    JETP letters 63 (1996), S. 937-943 
    Details
    ISSN: 1090-6487
    Keywords: 95.30.Sf ; 95.35.+d ; 14.80.Ly
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Microlensing of background stars by neutralino stars, which were proposed in a recent work by Gurevich and Zybin as the component making the main contribution to the dark matter, is studied. The optics of such a gravitational microlens—the equation of the lens, the solution of this equation, the intensification of images, and the critical and caustic curves—are analyzed in detail in a quite simple approximation. A set of different values of the parameters of the problem is studied.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1134/1.567124
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 6
    Electronic Resource
    Electronic Resource
    Polymorphisms of Ag-stained nucleolar organizer regions in man (1982)
    Springer
    Human genetics 〈Berlin〉 60 (1982), S. 334-339 
    Details
    ISSN: 1432-1203
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Polymorphisms of the NORs as tested by Ag-staining of metaphase G-banded chromosomes were investigated in cultured blood lymphocytes of karyotypically normal individuals from the Moscow population. The study of cell-to-cell variability in the number of Ag-stained NORs carried out on 14 monozygotic twin pairs showed the phenomenon to have some features of real intercellular variation. In 40 unrelated individuals the individual acrocentric chromosomes were compared by the number of Ag-stained NORs, their degree of staining, and their participation in acrocentric association. Chromosome 21 was found to be significantly more active than four others by all the criteria, and chromosome 15 was less active compared with the others by the size of the Ag deposits and the frequency of participation in NOR associations. The frequency distribution of homozygotes and heterozygotes for Ag-stained NORs in the same group of 40 individuals was in accordance with the Hardy-Weinberg law.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00569214
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 7
    Electronic Resource
    Electronic Resource
    Intercellular NOR-Ag-variability in man. II. Search for determining factors, clonal analysis (1985)
    Springer
    Human genetics 〈Berlin〉 69 (1985), S. 151-156 
    Details
    ISSN: 1432-1203
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Intercellular, nonartifactual variability of nucleolar organizer region (NOR)-Ag-staining was studied in cultured human peripheral blood lymphocytes, skin and embryonic fibroblasts. No differences in number and character of variable NORs and intensity of their staining were observed between lymphocytes stimulated to proliferate with phytohemagglutinin and pokeweed mitogen, as well as lymphocytes of first- and second division. The number of NOR associations per cell and the number of associated chromosomes per association were also similar. In a given individual these criteria were similar in lymphocytes and fibroblasts. In all nine clones derived from three independent parental fibroblast cultures the intercellular NOR-Ag-variability was similar to that observed in a given parental cell line. A significant decrease in the number of metaphases containing NOR associations was observed in second-division lymphocytes compared with first-division ones, as well as in skin fibroblasts compared with lymphocytes.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00293287
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 8
    Electronic Resource
    Electronic Resource
    Intercellular NOR-AG variability in man (1984)
    Springer
    Human genetics 〈Berlin〉 68 (1984), S. 299-302 
    Details
    ISSN: 1432-1203
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary A new modification of the Ag I technique has been developed using human cultured blood lymphocytes, which involves ultra-violet irradiation of chromosome preparations during incubation in AgNO3. This technique enables detection in a short incubation time all NORs capable of being stained with silver. A peculiar morphological change in Ag-stainable NORs during the incubation is described, which can be used as a criterion of the completion of Ag staining. With the refined Ag-staining procedure, acrocentric marker chromosomes were studied which showed one or two satellite stalks within the same individual. Ag staining was highly coincident with this variability.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00292588
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 9
    Electronic Resource
    Electronic Resource
    Genetic determination of NOR activity in human lymphocytes from twins (1982)
    Springer
    Human genetics 〈Berlin〉 60 (1982), S. 24-29 
    Details
    ISSN: 1432-1203
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Activity of nucleolar organizer regions (NORs) was studied in cultured blood lymphocytes from 20 monozygotic (MZ) and 20 dizygotic (DZ) twin pairs. The number of Agstained NORs, the degree of staining, and the frequency of acrocentric associations were used as criteria of the NOR activity, the acrocentric chromosomes being identified by G-banding. Analysis of intrapair concordance as well as of intrapair variance showed the number of Ag+NORs and the size of Ag-deposits to be highly heritable traits. Intrapair differences in acrocentric association frequency were not significantly higher in DZ compared with MZ twins.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00281258
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 10
    Electronic Resource
    Electronic Resource
    5-Bromodeoxycytidine in the study of sister chromatid exchanges in human lymphocytes (1980)
    Springer
    Human genetics 〈Berlin〉 55 (1980), S. 259-263 
    Details
    ISSN: 1432-1203
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary When [3H]dC was added with a high dose (4x10-1 mM) of dT to human blood lymphocyte cultures, much heavier labeling of interphase nuclei and metaphase chromosomes was observed compared with that in cultures treated with [3H]dC alone. This observation indicates that in the presence of excess dT, exogenous dC is included into cytosine bases of DNA, releasing the cells from the thymidine block. BrdC 5x10-2 mM added with a high dose of dT (4x10-1 to 1.0 mM) to the cultures did not relieve the thymidine block as determined from the percentage of metaphases of the first to third divisions. It is concluded that BrdC, in contrast to dC, is not utilized as a cytosine DNA precursor even in the presence of high concentrations of dT. The frequency of SCEs per cell was the same when studied with the aid of BrdC and BrdU used under similar conditions. The distribution of SCEs among chromosomes was also identical for both analogues: The number of SCEs was significantly higher than expected in chromosomes of group B and lower than expected in chromosomes of groups E, F, and G.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00291775
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...