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D Delafontaine

Publications and source records attributed to D Delafontaine.

At least 19 recordsLinked to original sources
PubMed1994

[Pachytene stage of meiosis in an infertile man carrying a reciprocal translocation between two acrocentric chromosomes].

Translocations involving acrocentric chromosomes are frequent in chromosomal male infertility. Robertsonian translocations are usually concerned whereas reciprocal translocations between acrocentric chromosomes are rarely encountered. The first reciprocal translocation involving the long arms of the two acrocentric chromosomes 13 and 14 [46,XY,t(13,14)(q33,q22)] is presented in this paper. The patient presents a severe oligoasthenospermia; testicular histology shows an important impairment of spermatogenesis. The quadrivalent is present in all the pachytene nuclei analyzed. A straight contact between the sex vesicle and the quadrivalent was found in 40.9% of the nuclei. A frequent asynapsis is localized at the breakpoint region (33.8%). The XY-autosome association was obtained by the central asynapsis and/or by the terminal chromomeres of the acrocentric chromosomes involved in the translocation.

Adult↗
PubMed1993

[Male infertility of chromosomal origin].

Cytogenetic studies in infertile men showed that chromosomal anomalies were more frequent in these patients than in general population. Sex chromosome anomalies, specially 47, XYY karyotype, are predominant by their frequency at the severity of testicular impair. Nevertheless, balanced autosomal rearrangements can also induce spermatogenic failure; they were of great interest in perfecting the hypothesis which try to explain germ cells atresia. Three mechanisms are proposed: --X-autosome interaction; --synaptic failure; both could lead to a metabolic disorder and death of the germ cell; --somatic lesions of the gonad could also induce this degenerative process. Techniques of molecular biology joined up to cytogenetic investigations of meiosis will lead to a better understanding of the chromosomal male sterility.

Chromosome Aberrations↗
PubMed1992

Very late return of spermatogenesis after chlorambucil therapy: case reports.

Two men were treated for a nephrotic syndrome with high-dose chlorambucil therapy; 6.5 and 14 years later, respectively, both were azoospermic with high plasmatic FSH values. Both patients showed active spermatogenesis, 15 and 19 years after the end of the treatment. This suggests that a return of spermatogenesis can occur even after very high cumulative doses of chlorambucil (between 3,000 and 6,500 mg) and after a very long time.

Adult↗
PubMed1992

Infertility in human males with autosomal translocations. II. Meiotic studies in three reciprocal rearrangements, one showing tertiary monosomy in a 45-chromosome individual and his father.

The meiotic prophase behavior of three human reciprocal autosomal translocations is presented. Each translocation was ascertained among men attending an infertility clinic. Two involved chromosomes 3 and 5, with breakpoints in different places. Quadrivalents were seen in every cell. The third translocation was a rare t(11q;15q) rearrangement in a 45-chromosome individual with tertiary monosomy. The long product of the translocation was retained in the karyotype over two generations of the family, the short product having been lost. At meiotic prophase, a trivalent was seen in every cell; in 60% of the nuclei, the short arm of the trivalent was closely associated with the XY bivalent. The transmission and phenotypic effects of tertiary monosomy in man and the mouse are discussed.

Chromosome Deletion↗
PubMed1991

Three dimensional reconstruction of human pachytene spermatocyte nuclei of a 17;21 reciprocal translocation carrier: study of XY-autosome relationships.

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.

Cell Nucleus↗
PubMed1987

Pachytene analysis in a 17;21 reciprocal translocation carrier: role of the acrocentric chromosomes in male sterility.

Pachytene analysis was undertaken in an infertile male, heterozygous for a 17;21 reciprocal translocation. The quadrivalent was identified by its configuration and chromomere pattern. A non-random association was found between the quadrivalent and the sex vesicle in 77% of the pachytene nuclei analysed. In 13.1% of the cells the contact with the sex vesicle was established by the terminal chromomere of the two chromosomes 21; in 63.9% of the cells, the entire region of the breakpoints was completely hidden by the sex vesicle. In some nuclei asynapsis was found in the region of the breakpoints. The nature of the contact between the quadrivalent and the sex vesicle is discussed in this paper. It is proposed that the acrocentric chromosome favours the contact between the quadrivalent and the sex vesicle, and increases the risk of sterility in male carriers of Robertsonian translocations and of reciprocal translocations involving one acrocentric chromosome.

Adult↗
PubMed1986

Loop formation and synaptic adjustment in a human male heterozygous for two pericentric inversions.

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.

Adult↗
PubMed1986

Meiotic behaviour of familial pericentric inversions of chromosomes 1 and 9.

Pachytene analysis was carried out in two infertile brothers, one heterozygous for two pericentric inversions of chromosomes 1 and 9, the second heterozygous for the pericentric inversion of chromosome 1. The synaptic behaviour of the bivalent 1 inversion was the most informative. Analysis of the chromomere pattern combined with centromeric heterochromatin staining and synaptonemal complexes visualization allowed precise description of synaptic initiation and extension leading to the homosynapsed loop. Heterosynapsis following alignment of the inverted segments was demonstrated. Non-homologous synapsed bivalents had the morphological aspects of straight bivalents with two distant blocks of centromeric heterochromatin. The possible sterilizing effect caused by the autosomal inversion is discussed.

Adult↗
PubMed1985

[Sclerosis of varicoceles. Apropos of 132 cases].

Endovascular sclerosis of the spermatic veins would seem to be the first step in the management of varicoceles, if these are considered to be responsible for hypofertility. In a series of 132 cases, the success ratio was 94 per cent on the right and 96 per cent on the left. The recurrence rate of 2 to 4 per cent would seem lower than in the case of surgical treatment (6 to 10 per cent). Moreover, the social and economic price of this ambulatory treatment is far lower. Surgical management would thus seem only indicated in the event of failure, and in the event of anatomical variations in the veins.

Fatty Alcohols↗
PubMed1980

Semen analysis in subfertile balanced-translocation carriers.

The spermograms of 19 subfertile translocation carriers were analyzed. Most of these men had moderate oligo-/astheno-/teratospermia. The results were widely spread, and some reached normal values, suggesting that autosomal rearrangement of the karyotype does not lead to severe oligospermia or azoospermia as do sex chromosome aberrations. No statistically significant differences in sperm count, motility, or morphology were found when semen analysis results of subfertile balanced-translocation carriers were compared with those of subfertile men with normal karyotypes. Since semen analysis alone is insufficient to allow prediction of an autosomal rearrangement of the karyotype, chromosome analysis should become a part of the routine investigation of subfertile men. The association between translocation heterozygosity and reduced fertility in men cannot be easily explained. The possible reasons underlying impaired spermatogenesis in some translocation carriers are discussed in relation to meiotic findings in animals.

Adult↗
PubMed1980

[Azoospermia].

Explore the source record for details and available documents.

Humans↗
PubMed1980

["In vitro" glass fiber filtration of sperm (author's transl)].

Filtering sperm through glass fiber has been suggested as a method for improving its fecundity before homologous artificial insemination. Various technical modification of this procedure have enabled good results to be obtained on spermatozoid mobility but at the expense of a marked drop in numbers: sperm counts per ml are diminished by a half. A comparative in vitro study of the penetration of filtered and non-filtered sperm into the cervical mucus showed that glass fiber filtration produced generally no great improvement, and may indeed reduce penetration into the cervical mucus to a marked degree in some cases.

Cervix Mucus↗