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  • 1
    ISSN: 1432-0886
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract The distribution of chromatid aberrations induced by mitomycin C among the individual chromosomes of female and male Chinese hamster cells in vitro was studied. The aberrations were found to be non-randomly distributed. Among the autosomes, the chromosomes possessing constitutive heterochromatin were more often involved in aberrations as well as in homologous exchanges. The inactivated X chromosomes in the female cells offer a situation where the short arm is facultatively heterochromatic and the long arm constitutively heterochromatic, thus enabling an analysis of their response for aberration formation. The short arm was seldom found to be involved in the aberration. The long arm of the inactivated X was more often affected (5 to 10 times) than the long arm of the functional X though both are constitutively heterochromatic. The possible role of (a) structure of heterochromatin, (b) the chromocenter formation and their association, (c) allocycly, and (d) the qualitative differences in the DNA of different types of heterochromatin are discussed in relation to the formation of chromatid aberrations.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Inflammation research 3 (1973), S. 77-85 
    ISSN: 1420-908X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Possibilities and limitations in the use of in vivo cytogenetic tests on somatic cells are discussed. Special attention is focused on the problems raised by the relative insensivity of the available procedures. It is emphasized that in planning screening tests the accumulated experience from studies with known chromosome breaking chemicals must be taken into account; theoretical considerations should not override the actual observations. In the Appendix, technical details of the micronucleus test are given. Furthermore, some thoughts are expressed concerning cytogenetic testing on germ cells and embryos.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Human genetics 〈Berlin〉 11 (1971), S. 119-131 
    ISSN: 1432-1203
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary 1. Chinese hamster fibroblast cell cultures were exposed to the alkylating mutagen, Trenimon, for 8 and 24 hrs; human fibroblast and lymphocyte cultures for 24 hrs. The dose range tested in each experiment comprised the entire span from concentrations causing aberration frequencies close to control levels up to those causing mitotic inhibition. 2. In all test systems a clear dose-response relationship was observed. The curves for different degrees of chromosome damage (1–2 aberrations; multiple aberrations; pulverized chromosomes) showed a similar pattern in all systems. 3. In Chinese hamster fibroblasts a 24 hrs exposure proved to be much more effective than an 8 hrs exposure: for a level of 50% damaged cells the drug concentration had to be increased 60-fold in the 8 hrs test. Practically no pulverized metaphases were produced in the 8 hrs experiment whereas over 70% pulverized mitoses appear after a 24 hrs exposure to the highest tolerable concentrations. 4. Major differences in the sensitivities of the three different test materials were found. The Chinese hamster fibroblasts proved to be most susceptible, but also showed the highest rate of spontaneous chromosome breakage. Human lymphocytes were the least sensitive. The differences found in drug sensitivity at the 50% damage level were about 15-fold between Chinese hamster and human fibroblasts and 70-fold between human fibroblasts and human lymphocytes. 5. Compared to the in vivo bone marrow system which responds to a very narrow dose range only (16x), the 24 hrs fibroblast system responded with a complete pattern of dose-response curves within a 32,000-fold difference between the highest and lowest test concentrations.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Springer
    Human genetics 〈Berlin〉 24 (1974), S. 93-104 
    ISSN: 1432-1203
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Description / Table of Contents: Zusammenfassung Unter 130 vorwiegend präpuberalen Patientinnen mit Merkmalen des Turner-Syndroms wurde bei 89 ein abnormer Geschlechtschromosomen befund erhoben, nämlich 61 Fälle von XO, 11 XXqi und XO/XXqi, 8 XO/XX, 6 XO/XXr, 1 45,XO/47,XY,+18 und 1 XO/XXq-. 5 der 11 Isochromosomen des langen X-Armes waren vom dizentrischen Typus, wobei unsere Befunde darauf hinweisen, daß dieser Typus instabil ist und deshalb öfter aus den Zellen verlorengeht als die monozentrischen Isochromosomen. Bei Patientinnen mit XO/XX-Mosaik ergab sich ein interessanter Befund bezüglich der Größe der Mosaikbezirke in der Epidermis. Der Mosaizismus war in 80% der Präparate einzelner Kopfhaare, Augenbrauen-, Axillar- und Pubeshaare nachweisbar. Dies stimmt gut überein mit klinischen Beobachtungen über das Mosaikmuster bei heterozygoten Frauen für die X-chromosomale, anhidrotische ektodermale Dysplasie: In den erwähnten Körperregionen fehlen alle Hinweise auf ein Mosaik von makroskopischem Ausmaß, dies im Gegensatz zum großflächigen Mosaizismus an Teilen des Stammes und der Extremitäten.
    Notes: Summary Of 130, mostly prepubertal girls with features of Turner's syndrome, 89 had an abnormal sex chromosome complement, namely 61 XO, 11 XXqi and XO/XXqi, 8 XO/XX, 6 XO/XXr, 1 XO/XY, 1 45,XO/47,XY+18, and 1 XO/XXq-.5 of 11 isochromosomes for the long X arm were of the dicentric type. Our data indicate that this type is unstable and there-fore is lost from the cells more often than monocentric isochromosomes. In XO/XX mosaics an interesting observation was made concerning the pattern size of mosaic areas in the epidermis. Mosaicism was demonstrable in 80% of preparations from single hair roots from the scalp, the eyebrows, the axilla, and the pubic region. This finding agrees with clinical observations on mosaic pattern size in heterozygotes for anhidrotic ectodermal dysplasia; absence of a macroscopical mosaic in the mentioned body regions, in contrast to the large pattern size evident in the epidermis of portions of the stem and extremities.
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  • 5
    Electronic Resource
    Electronic Resource
    Springer
    Human genetics 〈Berlin〉 25 (1974), S. 171-177 
    ISSN: 1432-1203
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Mosaicism for an extra chromosome 9 was found in an underweight male newborn with multiple malformations. Clinical findings included a peculiar face with hypertelorism, mongoloid position of the eyes, narrow palpebral fissures, enophthalmos, broadbased nose with bulbous tip, high-arched palate, short mandible, dysmorphic ears with a unilateral preauricular tag, thoracic kyphosis, 13 ribs bilaterally, cryptorchidism, flexion position of the hands and fingers, muscular hypotonia, and severe psychomotor retardation. An additional chromosome 9 was found in half of the lymphocyte mitoses, but not in fibroblasts. In addition, pericentric inversion of the heterochromatic segment of 1 chromosome 9 was found in the mother and the diploid cells of the patient; the patient's trisomic cells exhibited 2 inversion chromosomes.
    Type of Medium: Electronic Resource
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  • 6
    ISSN: 1432-1203
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Description / Table of Contents: Zusammenfassung Im Zuge der Ausarbeitung möglichst einfacher Systeme zur Mutagenitätsprüfung chemischer Substanzen am Säugetier wurde abgeklärt, wie weit die Aanalyse an gewöhnlichen Knochenmarkausstrichen die aufwendigere Chromosomenuntersuchung zu ersetzen vermag. Chinesische Hamster wurden an 2 aufeinanderfolgenden Tagen mit verschieden hohen und in einem Langzeitversuch mit 12 täglichen Injektionen von niedrigen Dosen Trenimon behandelt. Es wurden Präparate von Knochenmark und Herzblut angefertigt und der Effekt unter den verschiedenen Dosen und zu verschiedenen Zeiten nach der Behandlung sowie am Ende des Langzeitversuches beurteilt. Neben einem rapiden Zellschwund bei höheren Dosen, der mit z. T. uneinheitlichen und nur schwer überblickbaren quantitativen Zelltypenverschiebungen im Knochenmark einherging, konnten verschiedene atypische Zell-und Kernformen beobachtet werden, die quantitativ in Abhängigkeit von Dosis und Zeit erfaßt wurden und bezüglich Häufigkeit und Morphologie mit bekannten cytogenetischen Befunden verglichen wurden. Es ließen sich z. T. weitgehende parallelen feststellen, und es konnte damit dieser hämatologisch-morphologischen Knochenmarkuntersuchung eine Bedeutung als relativ einfaches Testsystem zur Erfassung chromosomenschädigender Mutagene zugesprochen werden. Es wird vorgeschlagen, dieses Verfahren als “Mikrokern-Test” zu bezeichnen. Ein besonderer Vorteil der Methode liegt darin, daß sie, unabhängig von einem günstigen Chromosomensatz, bei verschiedensten Säugetierspecies durchgeführt werden kann.
    Notes: Summary Exploring systems for chemical mutagenicity testing in mammals it was investigated how far scoring of simple bone marrow smears can replace the more complicated chromosome analyses. Chinese hamsters were treated with Trenimon for 2 and for 12 days. Preparations were made from bone marrow and blood, and the effect of the drug was studied in relation to dose, time after treatment, and at the end of a 12 day treatment with low doses. With high doses a rapid depletion of the bone marrow was observed; the concommitant shift in the relative proportions of different cell types was found to be inconsistent and difficult to quantitate. On the other hand, a number of well defined structural nuclear anomalies were observed. Their incidence was found to be dependent on dose and time after treatment. These findings showed a high degree of correlation with the results of previous cytogenetic studies on the incidence of chromosome aberrations obtained under identical conditions. It was concluded that the hematological study of bone marrow is suitable as a relatively simple screening method in mutagenicity testing. It is proposed to call this procedure ”micronucleus test”. A particular advantage of the method is, that it can be applied, independently of a favorable karyotype, to various mammalian species.
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  • 7
    Electronic Resource
    Electronic Resource
    Springer
    Human genetics 〈Berlin〉 11 (1971), S. 103-118 
    ISSN: 1432-1203
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary 1. Endoxan and Trenimon, the alkylating agents tested, are potent cytostatic drugs, therapeutically acting through their mutagenic effects. To demonstrate their chromosome breaking effects in bone marrow, higher than the usual therapeutic doses in man had to be applied. Starting from these practical threshold doses the dose-response curves were, however, rising very steeply. 2. The extent of chromsome damage in individual cells was dose-dependent: after treatments in the lower dose range only metaphases with one or few chromatid aberrations were observed in a small percentage of the mitotic figures. With increasing doses the number of aberrations per cell steadily rose to the point of complete pulverization of the chromosome complement. 3. After the last application of the test substances the cell population with visible chromosome damage diminuishes soon. The maximum incidence of aberrations was observed after 6–8 hrs. 4. The effect was several times higher after two applications spaced by 24 hrs than after a single application. With Endoxan given per os the incidence of affected cells was 8 times higher, with Trenimon i.p. 2–3 times. A longer oral treatment is less effective due to the radiomimetic damage to the intestinal mucosa thereby reducing further resorption of the mutagenic compound. Only a relatively small increase in effect is gained with more than two intraperitoneal applications; if there is a severe mutagenic effect, the animals begin to succumb to the treatment after 4 days. 5. A prolonged treatment with low doses of Endoxan (8 mg/kg daily for 7 weeks) produced no increase in the very low aberration incidence.
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  • 8
    Electronic Resource
    Electronic Resource
    Springer
    Human genetics 〈Berlin〉 22 (1974), S. 287-298 
    ISSN: 1432-1203
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Description / Table of Contents: Zusammenfassung Drei Patienten mit unvollständiger Trisomie für Chromosom 13 werden vorgestellt, ein Fall von Mosaik-Trisomie und je einer mit partieller Trisomie für den proximalen und distalen Teil des langen Arms. Die Patientin mit Trisomie 13-Mosaik wies neben geringeren dysmorphen Merkmalen Mikrocephalie, einen komplexen Herzfehler und eine Rotationsanomalie des Darmes auf. Nur ein Viertel der Mitosen aus den Lymphocyten und ein Drittel aus Hautfibroblasten waren trisom; das klinische Bild der Patientin erinnert kaum an eine Trisomie 13. Von zwei Söhnen einer Mutter mit balancierter Translokation 13/17 zeigte der Karyotyp des einen eine partielle Trisomie des proximalen, der des anderen eine partielle Trisomie des distalen Abschnittes des langen Arms von Chromosom 13. Der Knabe mit partieller Trisomie für die distalen zwei Drittel des langen Arms wies einige charakteristische Merkmale des Pätau-Syndroms auf, so Wachstumsrückstand, Idiotie, Hämangiome, Hexadaktylie und lange gebogene Wimpern, während sein Bruder mit partieller Trisomie für das proximale Drittel von normaler Größe war und neben einem schweren Intelligenzdefekt nur wenige körperliche Anomalien zeigte, wie kleines Kinn, Strabismus und Nystagmus, Kryptorchismus und kurze Kleinfinger. Eine Übersicht über andere Veröffentlichungen von partieller Trisomie 13 zeigt, daß typische Merkmale des Pätau-Syndroms in der Regel zwar bei partieller Trisomie für den distalen Abschnitt des langen Arms gefunden werden, nicht aber bei partieller Trisomie für den proximalen Anteil; bei letzterer fügen sich die wenigen dysmorphen Merkmale zu keinem spezifischen Syndrom.
    Notes: Summary Three cases with different forms of incomplete trisomy 13 are described; 1 was mosaic and 2 were partially trisomic for the distal and proximal long arm, respectively. The female patient who was mosaic for trisomy 13 exhibited microcephaly, minor dysmorphic features, a complex congenital heart defect, and malrotation of the intestine. The supernumerary No. 13 chromosome was present in only one fourth of blood lymphocyte and one third of skin fibroblast mitoses; her clinical picture has little in common with the usual trisomy 13 syndrome. Two sons of a mother with a balanced 13/17 translocation were found to be trisomic, one for the proximal third and the other for the distal two-thirds of the long arm of chromosome 13. The boy trisomic for the distal two-thirds showed some signs typical for the full trisomy 13 syndrome, such as stunted growth and severe mental retardation, long, incurved eyelashes, hemangiomata, and hexadactyly, whereas his brother, who is trisomic for the proximal third of the long arm of chromosome 13, presented rather unspecific clinical signs such as small chin, strabismus and nystagmus, cryptorchidism, and incurved little fingers. A review of other cases trisomic for these two segments shows that typical features of trisomy 13 are usually present in trisomy for the distal part of the long arm, and that duplication of, the proximal part leads to an unspecific clinical picture of mental retardation and minor dysmorphic traits.
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  • 9
    Electronic Resource
    Electronic Resource
    Springer
    Human genetics 〈Berlin〉 15 (1972), S. 163-171 
    ISSN: 1432-1203
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Description / Table of Contents: Zusammenfassung Es wird über einen Knaben mit einem charakteristischen Dysmorphiesyndrom bei partieller Trisomie des kurzen Armes von Chromosom 4 berichtet, der im Alter von 7 Monaten verstarb. Der Patient wies die folgenden Merkmale auf: eigenartiges Gesicht mit Hypertelorismus, enge Lidspalten und an der Basis eingezogene, knollig deformierte Nase, dysmorphe Ohrmuscheln, einseitiges Fehlen der 12. Rippe, Hüftgelenksluxation, Deformität des knöchernen Beckens, Hakenfüße mit hypoplastischen Tali und vorspringenden Fersen, Flexionsdeformität der Finger, Kryptorchismus, Leistenhernie und im Dermatoglyphenbild Häufung von Wirbelmustern auf den Fingerbeeren. Im Karyotyp lag eine Translokation auf den langen Arm eines Chromosoms 18 vor, bei entsprechender reziproker Translokation beim Vater: t(4p-,18q+). Als Nebenbefund fand sich bei Vater und Sohn eine extreme Anisomorphie der Chromosomen 16, bedingt durch die Verlängerung des heterochromatischen, parazentrischen Abschnittes auf dem langen Arm des einen Homologen.
    Notes: Summary A polymalformed boy is described with partial trisomy for the short arm of chromosome 4. The patient who died at the age of 7 months presented the following malformations and dysmorphic features: odd face with hypertelorism, narrow palpebral fissures and a stubby nose with depressed bridge, malformed ears, unilateral absence of the 12th rib, dislocation of the hips, bony malformation of the pelvis, rockerbottom feet, flexion deformity of the fingers, cryptorchidism, inguinal hernia, and an excess of whorls on the finger tips. The karyotype revealed an 18q+ with the corresponding reciprocal translocation in the father: t(4p-,18q+). In addition, father and son presented highly anisomorphic chromosomes 16 due to the presence of a heterochromatic elongation in the paracentric long arm region of one of the homologs.
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    Springer
    Sozial- und Präventivmedizin 15 (1970), S. 275-282 
    ISSN: 1420-911X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Zusammenfassung Durch die ständige Zunahme neuer chemischer Verbindungen in unserer Umwelt ist das Erbgut des Menschen durch nicht erkannte mutationsauslösende Substanzen gefährdet. Toxikologische Prüfungen werden deshalb in naher Zukunft auch der chemischen Mutagenese Rechnung tragen müssen. Das Problem ist infolge der metabolischen Umwandlungen im Säugetier-organismus bedeutend komplizierter als bei der ionisierenden Strahlung. Es wird eine Übersicht über die vorhandenen Testmöglichkeiten beim Säugetier sowie über in Entwicklung begriffene neue Testverfahren gegeben. Zur Illustration wird über eigene Resultate bei der Ausarbeitung eines Testsystems am Knochenmark von in vivo behandelten chinesischen Hamstern berichtet.
    Type of Medium: Electronic Resource
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