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  • 1
    Electronic Resource
    Electronic Resource
    The microtubular cytoskeleton and chromosomes of unfertilized human oocytes aged in vitro (1988)
    Springer
    Human genetics 〈Berlin〉 80 (1988), S. 259-264 
    Details
    ISSN: 1432-1203
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary To detect structural alterations in human oocytes that may give rise to predisposition to aneuploidy, unfertilized human oocytes from an IVF programme were processed for indirect anti-tubulin immunofluorescence. The spindle of oocytes aged for 2 days is rather small, and bi- or multipolar. Chromosomes are no longer aligned at the spindle equator but are scattered all over the degenerating spindle. This implies that human oocytes aged for 2 days may no longer be able to develop into a chromosomally balanced, normal embryo. In oocytes aged for 3–4 days the chromosomes become more decondensed and form a restitution nucleus. Microtubules radiate out from the latter towards the cell periphery and form a network of fibres in the cytoplasm. A similar alignment of tubules is found in unfertilized, activated oocytes. Oocytes with an aberrant cytoskeleton and chromosomal array were predominantly obtained from aged females. They include two binucleated oocytes with two sets of chromosomes and two oocytes with displaced chromosomes one of which had a tripolar spindle.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01790094
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  • 2
    Electronic Resource
    Electronic Resource
    Infertility in human males with autosomal translocations: meiotic study of a 14;22 Robertsonian translocation (1990)
    Springer
    Human genetics 〈Berlin〉 86 (1990), S. 162-166 
    Details
    ISSN: 1432-1203
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Pachytene analysis was undertaken in a male patient heterozygous for a 14q22q Robertsonian translocation. The relatively low rate of XY autosome association led us to examine the relationships existing between the chromosomes involved in the translocation, the rate of XY-autosome association and the degree of spermatogenic failure. Cytogenetic investigations in infertile men and the results of the meiotic studies suggest a direct correlation between the frequency of XY-autosome association at pachytene and the degree of spermatogenic failure. Whether associations arise as a consequence or cause of germ cell failure is still not certain.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00197698
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  • 3
    Electronic Resource
    Electronic Resource
    Three dimensional reconstruction of human pachytene spermatocyte nuclei of a 17;21 reciprocal translocation carrier: study of XY-autosome relationships (1991)
    Springer
    Human genetics 〈Berlin〉 87 (1991), S. 709-715 
    Details
    ISSN: 1432-1203
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary A study of XY-autosome relationships at the pachytene stage in an infertile 17–21 reciprocal translocation carrier was undertaken by means of three dimensional reconstruction. Synaptonemal complexes and the sex vesicle were analysed on electron microscopic serial sections and the reconstruction was performed on transparent sheets and on a Samba 2000 (Alcatel TITN) image analysis system. All asynapsed segments were entirely included in the sex vesicle, the chromatin fibre of the autosomes and sex chromosomes being tightly intermingled. In one nucleus, the four arms of the quadrivalent were paired, except around the breakpoints where an interstitial asynapsis was observed. In the other nuclei, a terminal asynapsis involving one or two arms of the quadrivalent was found. In the sex vesicle, autosomal asynapsed segments showed the same morphological characteristics as those of X and Y chromosomes. This observation agrees with the hypothesis of the extension of gene inactivation from sex chromosomes to autosomes.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00201730
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  • 4
    Electronic Resource
    Electronic Resource
    Complete pachytene chromomere karyotypes of human spermatocyte bivalents (1984)
    Springer
    Human genetics 〈Berlin〉 66 (1984), S. 267-271 
    Details
    ISSN: 1432-1203
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Well-spread human pachytene spermatocyte bivalents were obtained allowing specific identification of each bivalent within its total complement according to its chromomere sequence combined with further staining of its centromeric heterochromatin. The total number of chromomeres was found to be related to the degree of bivalent contraction: 396 in condensed bivalents and 511 in decondensed bivalents. A striking correspondance between chromomeres and mitotic G-bands was observed; on account of the variability of bivalent contraction, condensed bivalents corresponded to prometaphase somatic chromosomes and decondensed bivalents to mid/late prophase chromosomes.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00286614
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  • 5
    Electronic Resource
    Electronic Resource
    Synapsis and synaptic adjustment in an infertile human male heterozygous for a pericentric inversion in chromosome 1 (1986)
    Springer
    Human genetics 〈Berlin〉 72 (1986), S. 148-152 
    Details
    ISSN: 1432-1203
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Synapsis and “synaptic adjustment” were analyzed, using electron microscopy in silver stained surface microspreads of inversion-bearing spermatocytes, in an infertile human male with an inherited pericentric inversion in chromosome 1. Possible reasons for his infertility are discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00283934
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  • 6
    Electronic Resource
    Electronic Resource
    Loop formation and synaptic adjustment in a human male heterozygous for two pericentric inversions (1986)
    Springer
    Chromosoma 93 (1986), S. 313-320 
    Details
    ISSN: 1432-0886
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract Pachytene analysis was undertaken in an infertile male heterozygous for two pericentric inversions of chromosomes 1 and 9. The synaptic behaviour of the bivalent 1 inversion was the most informative. Analysis of the chromomere pattern combined with centromeric heterochromatin staining allowed precise description of synaptic initiation and extension leading to the homosynapsed loop. These techniques also allowed demonstration of the existence of heterosynapsis following alignment of the inverted segments. Non-homologous synapsed bivalents had the morphological aspects of straight bivalents with two distant blocks of centromeric heterochromatin. The numbering of the autosomal bivalent chromomeres at various successive phases of the inversion loop behaviour of bivalent 1 permitted us an alternative approach to the timing of pachytene.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00327589
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  • 7
    Electronic Resource
    Electronic Resource
    Meiosis of trisomy 21 in the human pachytene oocyte (1976)
    Springer
    Chromosoma 57 (1976), S. 155-163 
    Details
    ISSN: 1432-0886
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract Association modalities of the three 21 chromosomes were studied during pachytene in three trisomy 21 fetuses whose chromosomal constitution was identified following amniocentesis. — Three classes of images were observed: a trivalent, a trivalent presenting an important asynaptic region of the long arm, and a bivalent accompanied by a univalent. Such behaviour is analagous to that observed in all trisomic organisms. — We have been able to establish the sequence of chromomeres, whose number varies from 9 to 14 according to the state of contraction in the 21 chromosome. Each band is thus subdivided into several sub-bands: at maximal elongation 2 sub-bands for band p11, 4 for q21 and 3 for q222. In addition, the interchromomeric clear bands q221 and q223 are also subdivided by the presence of a very small chromomere. In this way, the G-bands visible on mitotic metaphase chromosomes result from the compression together of several chromomeres whose individuality disappears as chromosomal condensation increases with progression of prophase.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00292913
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  • 8
    Electronic Resource
    Electronic Resource
    Identification of pachytene bivalents in human male meiosis using G-banding technique (1975)
    Springer
    Chromosoma 52 (1975), S. 275-282 
    Details
    ISSN: 1432-0886
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract G-banding of human pachytene bivalents is obtained using trypsin digestion. Each, of the 22 autosomal bivalents is clearly identified. Such an identification leads to construction of the human pachytene map. Our results show the equivalence between the G-band patterns of mitotic chromosomes and meiotic bivalents. The G-band patterns of mitotic-meiotic chromosomes also correlate closely with the chromomere sequence of paehytene bivalents. Thus, study of chromomeres should constitute an excellent approach to comprehension of G-banding mechanism.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00332116
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  • 9
    Electronic Resource
    Electronic Resource
    Differential elongation of autosomal pachytene bivalents related to their DNA content in human spermatocytes (1988)
    Springer
    Chromosoma 97 (1988), S. 19-25 
    Details
    ISSN: 1432-0886
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract The establishment of the complete karyotype of human pachytene spermatocytes reveals differences in stretching of chromosomes between meiosis and mitosis. Bivalents or specific regions of bivalents which exhibit many R-bands are particularly elongated. In mitotic chromosomes, the DNA contained in such bands is known to be early replicating. The study of variations in the total length and the centromeric index of bivalent 1 suggests that differential elongation of pachytene bivalents is a premeiotic event, taking place during the last DNA replication.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00331791
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  • 10
    Electronic Resource
    Electronic Resource
    Constitutive heterochromatin and micronucleoli in the human oocyte at the diplotene stage (1975)
    Springer
    Human genetics 〈Berlin〉 26 (1975), S. 315-327 
    Details
    ISSN: 1432-1203
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary In the diplotene stage of the human oocyte, the processes of elaboration of the nucleolar material are amplified. The principal nucleoli are more voluminous but therir relations with the secondary constrictions and the satellites of the D and G chromosomes are not modified. Numerous micronucleoli, frequently to the number of 15–20, appear at this stage. The most remarkable point is their association to various segments of constitutive heterochromatin: centromeric regions, secondary constrictions of the C9 and probably of the A1 and E16. These observations reveal that the human oocyte at the diplotene stage shows an amplification of the ribosomal cistrons. This phenomenon is homologous, to a more reduced scale, of this described from the inferior vertebrates. Besides, the role of heterochromatin in the synthesis of nucleolar material without the intervention of the classic nucleolar organizers is suggested.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00285383
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