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  • 1
    Digitale Medien
    Digitale Medien
    Growth of Differentiating Testes and Ovaries (1969)
    [s.l.] : Nature Publishing Group
    Nature 224 (1969), S. 1323-1325 
    Details
    ISSN: 1476-4687
    Quelle: Nature Archives 1869 - 2009
    Thema: Biologie , Chemie und Pharmazie , Medizin , Allgemeine Naturwissenschaft , Physik
    Notizen: [Auszug] The gonads have a double origin. The somatic parts arise as ridges on the medial aspect of the middle half of the mesonephros while the germ cells migrate into these ridges from an extra-embryonic site4. For a while, the histological appearance of the gonads is the same in both sexes, but the ...
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1038/2241323a0
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  • 2
    Digitale Medien
    Digitale Medien
    Infertile couples with Robertsonian translocations: preimplantation genetic analysis of embryos reveals chaotic cleavage divisions (1998)
    Springer
    Human genetics 〈Berlin〉 102 (1998), S. 117-123 
    Details
    ISSN: 1432-1203
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Abstract Preimplantation genetic diagnosis (PGD) may provide a feasible option for some Robertsonian translocation carriers who experience severe difficulty in achieving a normal pregnancy. We report on five PGD cycles for two such couples, 45,XY,der(13;14)(q10:q10) and 45,XX,der(13;21)(q10;q10), carried out by biopsy of two cells from day 3 post-insemination embryos generated by in vitro fertilisation. Locus-specific YAC probes for chromosomes 13, 14 and 21 were used to detect the chromosomes involved in the translocation using multicolour FISH. Three embryos transfers were carried out (two single embryo transfers and one double transfer) but no clinical pregnancies were established. In two cycles no embryos were transferred as all those biopsied were chromosomally abnormal. Combined results from both couples show 13% (6/45) of embryos analysed were normal for the translocation chromosomes and 87% (39/45) were chromosomally abnormal; these were categorised as 36% aneuploid or aneuploid mosaic and 51% chaotic where the chromosome constitution varied randomly from cell to cell. This suggests two factors may be acting to reduce fertility in these couples; the aneuploid segregation of the parental Robertsonian translocation and also a post-zygotic factor leading to uncontrolled chromosome distribution in early cleavage stages in an exceptionally high proportion of embryos.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s004390050663
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  • 3
    Digitale Medien
    Digitale Medien
    Mechanisms of maternal aneuploidy: FISH analysis of oocytes and polar bodies in patients undergoing assisted conception (2000)
    Springer
    Human genetics 〈Berlin〉 106 (2000), S. 620-626 
    Details
    ISSN: 1432-1203
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Abstract. We have examined unfertilised oocytes and their first polar bodies (PBs) to determine the way in which the frequency of whole chromosome imbalance compares with that involving single chromatids and whether the precocious separation of chromatids prior to anaphase I affects all pairs of chromosomes. We have applied the technique of fluorescent in situ hybridisation in a three-stage method by using locus-specific probes for chromosomes 13 and 21 and α-satellite probes for chromosomes 1, 9, 16, 18 and X to determine the chromosome status of oocytes and their PBs. We obtained analysable results from 127 oocytes and 57 PBs from 72 patients of average age 33 years. Six oocytes and three PBs had extra signals but, of these, three were derived from a single patient, aged 26. Anomalies were seen in chromosomes 13, 16, 18, X and, notably, 21 but none were observed in chromosomes 1 and 9. Half of the anomalies involved additional chromatids rather than whole chromosomes. Since particular chromatids were found to be prematurely separated in the metaphase II oocyte, this may provide further evidence for an additional mechanism of maternal aneuploidy that operates at anaphase II. Detailed analyses of both oocytes and PBs have elucidated possible mechanisms leading to aneuploid gametes in this group of patients with fertility problems.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s004390000310
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  • 4
    Digitale Medien
    Digitale Medien
    Dual fluorescent in situ hybridisation for simultaneous detection of X and Y chromosome-specific probes for the sexing of human preimplantation embryonic nuclei (1992)
    Springer
    Human genetics 〈Berlin〉 89 (1992), S. 18-22 
    Details
    ISSN: 1432-1203
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Dual fluorescent in situ hybridisation has been used for the simultaneous detection of X and Y chromosome-specific probes in single cleavage nuclei from disaggregated 4- to 7-cell human embryos. Based on the presence of a Y signal or 2 X signals in the absence of a Y, 89% of poor quality metaphases and 72% of interphase nuclei could be classified as male or female. With further refinements, this technique will offer a credible alternative to the polymerase chain reaction for the diagnosis of sex in human preimplantation embryos in families segregating for X-linked genetic disease.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00207035
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  • 5
    Digitale Medien
    Digitale Medien
    Presence of chromosomal mosaicism in abnormal preimplantation embryos detected by fluorescence in situ hybridisation (1994)
    Springer
    Human genetics 〈Berlin〉 94 (1994), S. 609-615 
    Details
    ISSN: 1432-1203
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Abstract The extent of chromosomal mosaicism in human preimplantation embryos was examined using an improved procedure for the preparation and spreading of interphase nuclei for use in fluorescence in situ hybridisation, allowing the analysis of every nucleus within an embryo. One cell showed no hybridisation signals in only three of the 38 embryos that were included in this study, i.e. the hybridisation efficiency per successfully spread nucleus was 99% (197/200). Double-target in situ hybridisation analyses with X- and Y-chromosome-specific probes was performed to analyse nine embryos resulting from normal fertilisation, 22 polypronucleate embryos and seven cleavage-stage embryos where no (apronucleate) or only one pronucleus (monopronucleate) was observed. We also analysed autosomes 1 and 7 by double-target in situ hybridisation in the nuclei of two apronucleate, one monopronucleate and four polypronucleate embryos. All nine embryos that resulted from normal fertilisation were uniformly XY or XX. None of the apronucleate or monopronucleate embryos was haploid: three were diploid, one was triploid and three were mosaic. Fertilisation was detected by the presence of a Y-specific signal in four of these embryos. Of the polypronucleate embryos, two were diploid, two were triploid and 18 were mosaic for the sex chromosomes and/or autosomes 1 and 7. These results demonstrate that fertilisation sometimes occurs in monopronucleate embryos and that chromosomal mosaicism can be detected with high efficiency in apronucleate, monopronucleate and polypronucleate human embryos using fluorescence in situ hybridisation.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00206952
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  • 6
    Digitale Medien
    Digitale Medien
    Identification of novel Asian Indian and Japanese mutations causing β-thalassaemia in the Egyptian population (1997)
    Springer
    Human genetics 〈Berlin〉 99 (1997), S. 271-274 
    Details
    ISSN: 1432-1203
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Abstract β-thalassaemia is a major health problem in Egypt. It has been estimated that of the 1.5 million live births, 1000 children with β-thalassaemia major are born annually. Although the available treatment has increased the life expectancy of patients, it is still unsatisfactory and represents a significant drain on the country’s resources. National screening and prenatal diagnosis programmes can be provided in Egypt once the spectrum of β-thalassaemia mutations has been identified within the Egyptian population. We have examined 16 DNA samples with 21 β-thalassaemia mutations that remained unidentified in a study of 54 patients reported by Rady and colleagues in 1996. Using the polymerase chain reaction and single strand conformation analysis we identified the following changes: frameshift (FS) codon (CD) 8/9 (+G), 4 FS CD 29 (–G) and 2 novel mutations in exon I (15 CD 22 A-C and 1 FS CD 28 –C). In addition, a silent, probably polymorphic mutation, CD 17 G-A was present in all chromosomes.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s004390050352
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  • 7
    Digitale Medien
    Digitale Medien
    Preimplantation Genetic Diagnosis of Inherited Cancer: Familial Adenomatous Polyposis Coli (1998)
    Springer
    Journal of assisted reproduction and genetics 15 (1998), S. 140-144 
    Details
    ISSN: 1573-7330
    Schlagwort(e): familial adenomatous polyposis coli ; cancer predisposition ; preimplantation diagnosis
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Purpose: Our purpose was to achieve preimplantation genetic diagnosis (PGD) of the dominant cancer predisposition syndrome, familial adenomatous polyposis coli (FAPC), as an alternative to prenatal diagnosis. Methods: The affected patient was superovulated and oocytes were retrieved and fertilized by intracytoplasmic sperm injection (ICSI). Two cells were biopsiedfrom each embryo and the whole genome was amplified by primer extension preamplification (PEP). Nested PCR was then used to amplify two APC fragments: one including the APC mutation site and the other an informative intragenic polymorphism. Both were detected by simultaneous singlestrand conformation polymorphism and heteroduplex analysis. Results: Four normally fertilized embryos were biopsied on day 3 post ICSI, and two cells were successfully removed from each embryo. Following PEP the APC mutation was successfully amplified in 7 of 8 cells, and the polymorphism in 6 of 8 cells. The APC mutation was detected in three embryos. This result was confirmed by identification of the mutation associated polymorphism in two cases. A single embryo was diagnosed as homozygous normal for the mutation and the polymorphism in both cells sampled. This unaffected embryo was transferred to the mother, but no pregnancy resulted. Conclusions: We report here the first diagnosis of a cancer predisposition syndrome in human preimplantation embryos. Our results indicate that difficulties associated with single-cell PCR, allele-specific amplification failure in particular, need not prevent preimplantation diagnosis of diseases with a dominant mode of inheritance, provided appropriate strategies are applied.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1023008921386
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  • 8
    Digitale Medien
    Digitale Medien
    Detection of chromosomal abnormalities in human preimplantation embryos using FISH (1996)
    Springer
    Journal of assisted reproduction and genetics 13 (1996), S. 137-139 
    Details
    ISSN: 1573-7330
    Schlagwort(e): multicolor FISH ; preimplantation embryos ; mosaicism ; chromosomal abnormalities
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Purpose: Multicolour FISH has been used for the preimplantation diagnosis of sex for X-linked disorders and to examine the chromosome constitution of early human embryos. Materials and Methods: Single blastomeres and whole embryos were spread using HCl and Tween 20. Multicolour FISH was performed using directly-labelled human DNA probes for chromosomes X, Y, and I in a two hour FISH procedure. Results: Four groups of chromosome arrangements have been found in human preimplantation embryos (i) normal, all nuclei uniformly diploid, (ii) diploid mosaics, majority of the nuclei diploid, with a small number of nuclei aneuploid (iii) chromosomally abnormal, all nuclei uniformly chromosomally abnormal, e.g. XO, XXY, XXX and (iv) chaotic, all nuclei showing different chromosome complements. Conclusions: For the preimplantation diagnosis of sex, an XX nucleus has always been representative of a female embryo. However, for the diagnosis of dominant disorders or chromosome abnormalities, two cells should be analysed to reduce the chance of misdiagnosis which may arise from chromosomal mosaicism. Implantation and further embryo development may be possible from mosaic or chromosomally abnormal embryos, but those showing chaotic chromosome arrangements would be unlikely to implant.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF02072535
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  • 9
    Digitale Medien
    Digitale Medien
    Clinical experience with preimplantation diagnosis of sex by dual fluorescent in situ hybridization (1994)
    Springer
    Journal of assisted reproduction and genetics 11 (1994), S. 132-143 
    Details
    ISSN: 1573-7330
    Schlagwort(e): preimplantation diagnosis ; fluorescent in situ hybridization (FISH) ; embryo biopsy ; X chromosome ; Y chromosome
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Purpose Our purpose was to assess the clinical application of dual fluorescent in situhybridization (FISH) for the diagnosis of sex in the human preimplantation embryo. Results Over a 2-year period, 18 couples at risk of transmitting X-linked recessive disorders underwent preimplantation diagnosis of embryo sex by dual FISH with X and Y chromosome-specific DNA probes. A total of 27 in vitro fertilization (IVF) treatment cycles led to nine pregnancies; 7 reached the stage of clinical recognition, of which 2 spontaneously aborted. There were five live births, three singleton and two twin: none in disagreement with the diagnosed sex. The diagnosis was corroborated in 51 of the 74 nontransferred embryos. The efficiency of the procedure improved throughout the four treatment cycles. This was reflected in the increased proportion of double embryo transfers (from 50% in series 1 and 2 to 100% in series 3 and 4), with a consequent improvement in pregnancy rate (from 28 to 71% per embryo transfer). The excess of male embryos (male∶female, 60∶40 overall) and the high proportion of biopsied embryos with abnormal numbers of X and Y chromosome signals (14.5%) effectively reduced the number of normal female embryos available for transfer. Conclusion Dual FISH is an efficient technique for determination of the sex of human preimplantation embryos and the additional ability to detect abnormal chromosome copy numbers, which is not possible via the polymerase chain reaction, (PCR), makes FISH the preferred technique.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF02332090
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