PubMed Health⌕ Search

Biomedical subjects

Y Rumpler

Publications and source records attributed to Y Rumpler.

At least 55 records · Page 3Linked to original sources
PubMed1992

Heterosynapsis in two fertile but hypoprolific boars carriers of reciprocal translocations.

The authors report here two new cases of reciprocal translocations in two fertile and hypoprolific boars. Silver stained synaptonemal complexes in surface-spread pachytene nuclei from a boar heterozygous for a reciprocal translocation, and from another one carrying two different reciprocal translocations, were analyzed by electron microscopy. In such heterozygotes, cross-shaped quadrivalent configurations are expected to form in order to allow homologous pairing. In the same boar, the lengths of the fully synapsed arms of the quadrivalent varies from one quadrivalent to the other and heterosynapsis was obvious. Heterosynapsis was also observed with asymmetrical pairing of the non-homologous partners of the quadrivalent. This heterosynapsis is assumed to be a mechanism preventing spermatocyte loss, but inducing a secondary segregational type of impairment of fertility due to foetal wastage leading to reduced prolificacy.

Animals↗
PubMed1991

Cytogenetic study of Hapalemur aureus.

The karyotype of Hapalemur aureus was compared with those of other Hapalemur species, allowing us to determine the phylogenetic position of this species on the evolutionary tree of the Lemuridae.

Animals↗
PubMed1991

Synaptonemal complex analysis in a human male carrier of a 4;6 translocation: heterosynapsis without previous homosynapsis.

Silver-stained synaptonemal complexes in surface-spread pachytene nuclei from a man, heterozygous for a reciprocal translocation, were analysed by electron microscopy. Contrary to the classically expected cross-shaped configuration, extensive non-homologous pairings were observed with asymmetrical association in the lateral elements of the non-homologous arms of the quadrivalents. A possible role of the heterosynapsis in reproductive failure is discussed.

Adult↗
PubMed1991

Analysis of synaptonemal complexes in a heterozygous human male carrier of a reciprocal translocation involving an acrocentric chromosome: heterosynapsis without previous homosynapsis.

Silver-stained synaptonemal complexes in surface-spread pachytene nuclei from an oligospermic man, heterozygous for a reciprocal translocation involving an acrocentric chromosome, were analyzed by electron microscopy. Contrary to the classically expected configuration, nonhomologous pairing was observed with asymmetrical association of the lateral elements of the nonhomologous arms of the quadrivalents. A possible role of heterosynapsis in germ cell conservation is discussed.

Adult↗
PubMed1991

Confirmation, via in situ hybridization, of the occurrence of Robertsonian translocations during lemur evolution by localization of GLUDP1 DNA sequences on lemur chromosomes.

A human genomic DNA sequence derived from glutamate dehydrogenase pseudogene 1 was used as a probe for in situ hybridization to the chromosomes of three lemur species, Eulemur fulvus mayottensis (EFU), E. macaco macaco (EMA), and E. coronatus (ECO). This sequence, which is 98% homologous to the nucleotide sequence of the gene for human glutamate dehydrogenase (GLUD), was found on homologous bands of three morphologically similar chromosome segments, EFU14, EMA5p, and ECO8q, confirming that different Robertsonian translocations occurred during the evolution of these three species. These loci on the lemur chromosomes probably correspond to the human GLUD locus.

Animals↗
PubMed1990

Deletion of the pseudoautosomal region and lack of sex-chromosome pairing at pachytene in two infertile men carrying an X;Y translocation.

Two males with a 46,Y,der(X),t(X;Y)(p22.3;q11) complement were referred independently for evaluation of sterility with azoospermia. Both patients exhibited minimal symptomatology, characterized only by psychological disturbances. Study of X-chromosome breakpoints with pseudoautosomal probes 68B (DXYZ2 elements), 113D (locus DXYS15), and 19B (locus MIC2) indicated in both patients that at least 97% of the X pseudoautosomal sequences are lost. Hybridization with Xp22.3-specific probes DXS283, DXS284, and DXS31 shows that these loci are retained on the rearranged chromosome. Thus, the X-chromosome breakpoints are located close to the proximal boundary of the pseudoautosomal region, between MIC2 and DXS284.

Blotting, Southern↗
PubMed1990

[Chromosomal rearrangements and sterility in the lemur].

Autosomal rearrangements are one of the causes of human sterility, particularly in males, where they result in a considerable diminution of gametogenesis. The relationships between multivalents and trivalents, and problems of gametogenesis observed in certain lemur hybrids, make these animals a good model for the study of human male sterility of chromosomal origin.

Animals↗
PubMed1990

[Teratospermia and the fertilizing capacity of semen in the lemur].

As in fertile men, Lemur fulvus mayottensis spermatozoa are pleiomorphic. Percentage of structural defects of semen varies in breeding and nonbreeding seasons. Spermatozoa exhibit acrosomal and flagella abnormalities. These primates could serve as a useful model for teratospermia study, especially because this seasonal variation.

Acrosome↗
PubMed1989

Correlation between chromosomal breakpoint positions and synaptic behaviour in human males heterozygous for a pericentric inversion.

The examination of synaptic data and localization of chromosomal breakpoints in a review of human pericentric inversions suggest that synaptic and recombination behaviour in rearranged chromosomes during meiosis can be predicted by determining the subband in which the breakpoint is located. According to this hypothesis, it can be postulated that loops in pericentric inversions are routinely formed only in cases when both breaks occur in G-light bands, with the genetic consequences of crossing-over. In other cases, heterosynapsis is accomplished without previous homosynapsis, thereby minimizing the production of unbalanced gametes.

Centromere↗
PubMed1989

Pattern of ribonucleic acid synthesis in vitro in primary spermatocytes from mouse testis carrying an X-autosome translocation.

In an attempt to elucidate the mechanism of sterility of X-autosome translocations in the mouse, we studied the distribution of [3H]-uridine incorporation in sterile males carrying the balanced X-16 reciprocal translocation. The results failed to show an overall reactivation of the X as has been postulated by Lifschytz and Lindsley (1972) but there was some spreading of X inactivation along the translocated and normal chromosome 16 in those regions that were close to the X breakpoint. We feel that this process could be responsible for metabolic disturbances leading to degeneration of primary spermatocytes and, therefore, to sterility.

Animals↗
PubMed1989

Analysis of synaptonemal complexes in two fertile heterozygous boars, both carriers of a reciprocal translocation involving an acrocentric chromosome.

An electron microscopic study of synaptonemal complexes in two heterozygous fertile boars, one a carrier of a 4;14 reciprocal translocation and the second a carrier of this translocation associated with a 3;7 reciprocal translocation, is reported. The results showed heterologous pairing in almost all quadrivalents, as well as a lack of XY-quadrivalent association. This seemed to be a common feature of translocations in pigs, even if at least one acrocentric chromosome is involved, and may represent a significant meiotic mechanism that prevents spermatocyte loss, while the production of genetically unbalanced gametes leads to loss of progeny through abortion.

Animals↗