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Y Rumpler

Publications and source records attributed to Y Rumpler.

At least 37 records · Page 2Linked to original sources
PubMed1996

Sertoli cell barrier dysfunction and spermatogenetic cycle breakdown in the human testis: a lanthanum tracer investigation.

The introduction of nitrate of lanthanum in fixative solutions for testicular biopsies improves ultrastructural observations of the blood-testis barrier. In complete (normal) spermatogenesis, junctional specializations impede the diffusion of lanthanum into the adluminal compartment. They clearly exhibit a three-storied disposition in orthogonal sections. In maturation arrest, lanthanum passes easily through the junctional specializations surrounding the germ cells and up to the lumen. In irregular hypospermatogenesis, the Sertoli cell barrier is permeable, but diffusion of the tracer is less significant and variable. Unexpectedly, in germ cell aplasia, the barrier remains efficient

Humans↗
PubMed1996

Demonstration of homoeologies between human and lemur chromosomes by chromosome painting.

Human-specific probes for chromosomes 3, 7, 9, 14, 19, and 21 were used to paint chromosomes of three lemur species: Eulemur fulvus mayottensis, E. macaco macaco, and Lemur catta. Chromosomes 1 and 3 of E. f. mayottensis are homoeologous to human chromosomes 3, 9, 14, and 21, as previously suggested by chromosome banding. Probes for human chromosomes 7 and 19 produced unexpectedly strong signals in the centromeric regions of all lemur chromosomes, suggesting that sequences homologous to nonrepeated sequences of the human genome have been amplified during the formation of constitutive heterochromatin in lemurs.

Animals↗
PubMed1996

Synaptic behaviour of sex chromosome in two XYY men.

Analysis of meiotic pairing behavior in two XYY males presenting at subfertility clinic brings evidence that the abnormal mode of pairing caused by the presence of the extra Y chromosome, disturbs achievement of spermatogenesis resulting in severe oligoastheno-teratozoospermia. In contrast, the loss of the supernumerary Y before meiosis, allows achievement and normal sperm production.

Adult↗
PubMed1996

The meiotic pairing behaviour in human spermatocytes carrier of chromosome anomalies and their repercussions on reproductive fitness. II. Robertsonian and reciprocal translocations. A European collaborative study.

The pairing behaviour of pachytene chromosomes was studied in men carrier of Robertsonian and reciprocal translocations, by analysis of synaptonemal complexes at the electron microscopy level. The human meiotic data were collected from European laboratories in order to test the current theories and to link the spermatogenic breakdown, and the pregnancy wastage to the mode of pairing and their consequences.

Chromosome Aberrations↗
PubMed1995

Male sterility and double heterozygosity for chromosomal inversion.

A meiotic analysis has been carried out on male mice heterozygous for one of two inversions in Chromosome 2, In(2)5Rk and In(2)2H, as well as on double heterozygotes for these two overlapping inversions. Electron microscopic observation of synaptonemal complexes revealed that heterosynapsis had occurred in a large number of spermatocytes, producing a small number of cells with an inversion loop. Heterozygous carriers of a single inversion loop reproduced quite normally, whereas doubly heterozygous carriers of a double loop showed a reduction in spermatogenesis. These data shed new light on the role of inversions in speciation.

Animals↗
PubMed1994

Supernumerary chromosomes and spermatogenesis in a human male carrier.

A 57-year-old patient was referred because of primary sterility. Spermogram and testicular histology showed moderate oligospermia and irregular hypospermatogenesis. Karyotypic analysis revealed the presence of a metacentric supernumerary chromosome. Synaptonemal complex analysis using the surface-spreading technique was undertaken to study the meiotic behaviour of the extra chromosome during the pachytene stages. The relationship of the extra chromosome to the infertility of the carrier is discussed.

Chromosome Aberrations↗
PubMed1994

The meiotic pairing behaviour in human spermatocytes carrier of chromosome anomalies and their repercussions on reproductive fitness. I: Inversions and insertions. A European collaborative study.

The synaptic behavior of pachytene chromosomes was studied in men heterozygous for inversions and one inversion-insertion by analysis of synaptonemal complexes at the electron microscopy level. The human meiotic data were collected from European laboratories in order to test the current theories and to link the arrest of spermatogenesis and the risk of chromosome imbalance to the mode of pairing and their consequences. The breakpoint location would allow to predict the synaptic and recombinational behavior of chromosome aberrations and particularly the risk of aneusomie de recombinaison in the progeny of inversion carriers.

Aneuploidy↗
PubMed1993

Genome size and qualitative and quantitative characteristics of C-heterochromatic DNA in Eulemur species and in a viable hybrid.

The amounts of nuclear DNA and the AT and GC content of four Eulemur (Prosimii, Lemuridae) species and of an E. coronatus x E. macaco hybrid were measured by flow cytometry in peripheral blood leukocytes, following propidium iodide, Hoechst 33258, and mithramycin staining. Hoechst 33258 and mithramycin were also used to evaluate the base composition of genomic DNA in the chromosomes. The amount of DNA resisting C-banding pretreatment (C-heterochromatic DNA) was measured in metaphase chromosomes by static fluorometry. The genome of E. coronatus was significantly larger than the genomes of all other species examined, due to a higher content of pericentromeric, mainly GC-rich, heterochromatic DNA. The restriction banding patterns produced by BamHI digestion and ethidium bromide staining on extracted DNA were studied in the hybrid and its parental species (E. coronatus and E. macaco). The restriction banding pattern of the sole E. coronatus individual showed two bands which were repeated in the restriction banding pattern of the hybrid. The qualitative and quantitative differences of C-heterochromatic DNA in E. coronatus confirm the "splitting" processes and the phylogenetic relationships in the genus Eulemur suggested by Jung et al. (1992) on the basis of the restriction banding patterns produced by endonuclease digestion.

Animals↗
PubMed1993

Comparison of highly repeated DNA sequences in some Lemuridae and taxonomic implications.

Highly repeated DNA sequences of Eulemur fulvus mayottensis, E. coronatus, Lemur catta, and Hapalemur griseus griseus have been identified and compared. Sequence analysis of highly repeated DNA fragments isolated from L. catta and Hapalemur showed a high percentage of similarity (nearly 95%), as did fragments isolated from the two very close Eulemur species, whereas comparison of the DNA fragments isolated from the two Eulemur species and the L. catta/Hapalemur group showed a very low percentage (approximately 40%) of identity, as might be expected for distant species. These results confirm our previous data, obtained by Southern blot hybridization techniques on the same species, and strongly support the existence of a common trunk between L. catta and Hapalemur, but different from the leading to the Eulemur species.

Animals↗
PubMed1993

An X-Y homologous pairing segment in tree shrews (Tupaia).

High-resolution early replication banding of tupaia metaphase chromosomes revealed a synchronous early replicating segment in the short-arm telomeric regions of the active and inactive X chromosomes and in the long-arm telomeric region of the Y chromosome. Hybridization with the human-derived pseudoautosomal probe 113F (STIR) showed that this repeat is conserved and specifically localized within these synchronously early replicating segments of the X short arm and the Y long arm of all three tupaia species (Tupaia belangeri, T. chinensis, and T. glis) investigated. Moreover, meiotic studies demonstrated that a synaptonemal complex is formed at one telomeric end of the XY bivalent during the pachytene stage of meiosis in a male T. glis specimen. Thus, apart from the mouse, the tupaias are the first nonprimate mammals for which cytogenetic and molecular evidence is provided that their highly heteromorphic X and Y chromosomes share a conserved homologous segment in the telomeric position, a location that is compatible with pairing and crossing-over in male meiosis. Taken together, these observations strongly, albeit indirectly, suggest that this chromosome segment at the tip of a sex-chromosome arm might behave pseudoautosomally.

Animals↗
PubMed1993

Chromosomal anomalies and disturbance of transcriptional activity at the pachytene stage of meiosis: relationship to male sterility.

Morphological analysis of pachytene spermatocytes obtained from male mice carrying three chromosomal rearrangements--a Robertsonian translocation, Rb(X-2)2Ad; an autosomal reciprocal translocation, T(16;17)43H; and a tertiary trisomic, Ts(113)70H--demonstrated frequent association between the XY bivalent and the T43H and T70H translocation chromosomes. Quantitative autoradiographic data revealed that the normal transcriptional inactivity of the XY bivalent was not significantly disturbed, in contrast to that of the 16;17 quadrivalent and the extra 1(13) marker chromosome. These results are interpreted as an extension of the XY inactivation process to the associated autosomes and discussed in relation to male sterility.

Animals↗
PubMed1993

Confirmation of the taxonomic position of Callimico goeldi (Primates, Platyrrhini) on the basis of its highly repeated DNA patterns.

The systematic position of Callimico goeldi has been analyzed by comparison of its highly repeated DNA fragments with those of three species of Callithricidae and two species of Cebidae. Our data, in agreement with those obtained by other authors by means of cytogenetic and molecular biology techniques, are in favour of the classification of C. goeldi in the family Callithricidae.

Animals↗
PubMed1992

Cellular relationship impairment in maturation arrest of human spermatogenesis: an ultrastructural study.

Ultrastructural examination of testicular biopsies from cases of maturation arrest showed that there were characteristic abnormalities of the Sertoli cell junctional connections. These abnormalities together with the meiotic failure afford an explanation for the severe oligospermia or azoospermia noted in patients with maturation arrest. Premature setting up of ectoplasmic specializations in front of early spermatids and/or spermatocytes were also observed.

Adult↗
PubMed1992

Chromosomal rearrangements and speciation of sportive lemurs (Lepilemur species).

Theoretical configurations of meiotic chromosomes of potential hybrids between the different Lepilemur species were examined, and the classification of this genus was reviewed in the light of this information. Among the chromosomal rearrangements that occurred during the chromosomal evolution of the sportive lemurs, only those which would generate a pronounced reproductive barrier were considered in relation to the geographic distribution of this genus. The analysis showed that the pattern of geographic distribution is compatible with the inferred chronological occurrence of these chromosomal rearrangements in the phylogenetic tree of the genus Lepilemur.

Animals↗