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S Hamamah

Publications and source records attributed to S Hamamah.

At least 19 recordsLinked to original sources
PubMed2005

Sperm segregation analysis of a (13;22) Robertsonian translocation carrier by FISH: a comparison of locus-specific probe and whole chromosome painting.

BACKGROUND: The t(13;22) Robertsonian translocation constitutes a rare form of rearrangement between acrocentric human chromosomes. Most of the meiotic segregation studies of human Robertsonian translocations have been performed on common t(13;14) and t(14;21) translocations. Analysis of the chromosomal constitution in sperm of Robertsonian translocation carriers is of great interest for assessing the risk of unbalanced forms and adapting genetic counselling. In the present study, we present the first meiotic segregation study of a t(13;22) Robertsonian translocation in human sperm. METHODS: A total of 11 787 sperm nuclei were scored using two distinct FISH labelling techniques, i.e. the locus-specific probes (LSI) method and the whole chromosome painting (WCP) technique. RESULTS: The frequency of normal or balanced sperm resulting from alternate meiotic segregation was 86%. Incidences of unbalanced complements resulting from adjacent segregation modes were 12.79% and 14.36% in LSI and WCP assays, respectively. No significant excess of nullisomy or disomy for the affected chromosomes was observed. CONCLUSIONS: Similar results in segregation were obtained with the two techniques, demonstrating the efficiency of the two strategies for the direct segregation analysis of Roberstsonian translocations. The results obtained indicated a moderate meiotic production of imbalance. This study shows that the rare Robertsonian translocation (13;22) displays a similar distribution of balanced and unbalanced sperm patterns as the common Robertsonian translocations previously studied. This suggests that the behaviour of acrocentric chromosomes was similar in all cases of centric fusion.

Adult↗
PubMed2005

[The cytogenetics of human oocytes: 40 years of progress].

Chromosomal abnormalities account for the majority of pre- and post- implantation embryo wastage in humans. Most of these abnormalities result from maternal meiotic errors, which preferentially occur during the first meiotic division. Consequently, the cytogenetic analysis of human oocytes has then been considered as a highly valuable source of data for the investigation of both the occurrence and the origin of chromosomal abnormalities in human. During the last 4 decades, the cytogenetic analysis of human oocytes has never stopped progressing, according to the advents of new technologies. Both karyotyping and molecular cytogenetic studies have been reported to date, providing a large body of data on the incidence and the distribution of chromosomal abnormalities in human female gametes. However, these studies display a great variability in results, which may be essentially attributable to the limitations of these techniques when applied to human oocytes. The most relevant analysis have led to the estimate that 15-20% of human oocytes present chromosome abnormalities, and they have emphasized the implication of both whole chromosome non-disjunction and chromatid separation in the occurrence of aneuploidy in human oocytes. The effect of advanced maternal age on the incidence of aneuploidy in human oocytes has also been clearly evidenced by recent reports based on large sample of oocytes or polar bodies.

Cell Division↗
PubMed2005

[The Paris experience in preimplantation genetic diagnosis: evaluation after the first births].

OBJECTIVE: To report the birth of the first thirteen infants conceived after preimplantation genetic diagnosis (PGD) within the medical assistance federation of Paris. PATIENTS AND METHODS: Fifty-nine couples were enrolled between January 2000 and July 2001. They had a total of 71 oocyte pick-up cycles. The collected oocytes were inseminated by intracytoplasmic sperm injection. The resulting embryos were biopsied on the third day of development and the genetic analysis was performed on the same day. Most of the embryo transfers were carried out on the fourth day. RESULTS: The 71 oocyte pick-up cycles yielded 872 oocytes of which 731 were suitable for intracytoplasmic sperm injection. 421 embryos were biopsied and genetic diagnosis was obtained from 312 (74%) of these. 127 embryos were transferred during the course of 58 transfer procedures. There were 18 biologic and 12 clinical (7 singles, 4 twins and 1 triple) pregnancies. Thirteen infants have been born and 4 are expected. CONCLUSIONS: PGD has gained a place among the choices offered to couples at risk of transmission of a serious and incurable genetic disease.

Blastocyst↗
PubMed2005

Strategies for preimplantation genetic diagnosis of Angelman syndrome caused by mutations in the UBE3A gene.

Angelman syndrome (AS) is a neurodevelopmental disorder associated with the loss of maternal gene expression in chromosome region 15q11-q13. AS is caused by a wide variety of genetic mechanisms, including mutations in the UBE3A gene that have been identified in 10-15% of patients; when the mother is heterozygous for the causative mutation, the risk of recurrence in subsequent pregnancies is 50%. The present authors have developed a preimplantation genetic diagnosis (PGD) assay for a family displaying a 10 bp deletion in exon 9 of the UBE3A gene, which was shared by two affected children and their phenotypically normal mother. A duplex polymerase chain reaction protocol was established, allowing the efficient amplification of the mutation together with an informative microsatellite marker (D15S122) located in intron 1 of the UBE3A gene. As most of UBE3A mutations identified so far are unique to one family, the present authors have also developed an indirect single cell protocol based upon the co-amplification of two microsatellite markers located within (D15S122) and close to the UBE3A gene (D15S1506). This strategy may be applied to all informative families requesting PGD for Angelman syndrome associated with mutations in the UBE3A gene.

Alleles↗
PubMed2005

Effect of maternal age on the frequency of cytogenetic abnormalities in human oocytes.

The cytogenetic investigation of human oocytes was initiated in the Sixties, and for the last four decades, this field of research has never stopped progressing as new technologies appear. Numerous karyotyping studies and molecular cytogenetic studies have been reported to date, providing a large body of data on the incidence and the distribution of chromosomal abnormalities in human female gametes, but also displaying a great variability in results, which may be essentially attributable to the technical limitations of these in situ methods when applied to human oocytes. Essentially, the most relevant analyses have led to the estimate that 15-20% of human oocytes display chromosome abnormalities, and they have emphasized the implication of both whole chromosome nondisjunction and chromatid separation in the occurrence of aneuploidy in human oocytes. The effect of advanced maternal age on the incidence of aneuploidies has also been investigated in human oocytes. Most previous studies have failed to confirm any relationship between maternal age and aneuploidy frequency in human oocytes, whereas the more recent reports based on large samples of oocytes or polar bodies have provided evidence for a direct correlation between increased aneuploidy frequency and advanced maternal age, and have clarified the contribution of the various types of malsegregation in the maternal age-dependent aneuploidies.

Adult↗
PubMed2004

The chromosomal analysis of human oocytes. An overview of established procedures.

The cytogenetic survey of mature human oocytes has been and remains a subject of great interest because of the prevalence of aneuploidy of maternal origin in abnormal human conceptuses, and the lack of understanding about the non-disjunction processes in human meiosis. The first attempts to analyse the chromosomal content of human female gametes were made in the early 1970s, and led to limited data because of the paucity of materials and the inadequacy of the procedure used. The years to follow brought a resurgence of interest in this field, because of the development of human IVF techniques which made oocytes unfertilized in vitro available for cytogenetic analysis. Numerous studies have since been performed. However, the difficulties in obtaining good chromosome preparations and of performing accurate chromosome identification have reduced the viability of these studies, resulting in large variations in the reported incidences of chromosomal abnormalities. The further introduction of new procedures for oocyte fixation and the screening of large oocyte samples have allowed more reliable data to be obtained and to identify premature chromatid separation as a major mechanism in aneuploidy occurrence. The last decade has been privileged to witness the adaptation of molecular cytogenetic techniques to human oocytes, and thus various powerful procedures have been tried not only on female gametes, but also on polar bodies, involving sequential and multicolour fluorescent in situ hybridization (FISH) labelling, comparative genomic hybridization (CGH), spectral karyotyping and alternative methods such as primed in situ labelling (PRINS) and peptide nucleic acid (PNA) techniques. A large body of data has been obtained, but these studies also display a great variability in the frequency of abnormalities, which may be essentially attributable to the technical limitations of these in situ methods when applied to human oocytes. However, molecular cytogenetic approaches have also evidenced the co-existence of both whole chromosome non-disjunction and chromatid separation in maternal aneuploidy. In addition, the extension of these techniques to oocyte polar body materials has provided additional data on the mechanism of meiotic malsegregation. Improvements of some of these techniques have already been reported. The further development of new approaches for the in situ analysis of human meiosis will increase the impact of cytogenetic investigation of human oocytes in the understanding of aneuploidy processes in humans.

Aneuploidy↗
PubMed2004

The peptide nucleic acids: a new way for chromosomal investigation on isolated cells?

The development of nucleic acid analogues has become an important feature due to the potential use of this new biomolecular tool in genetic diagnostics and investigations. Among all the synthetic oligonucleotides designed, the peptide nucleic acids (PNA) constitute a remarkable class of nucleic acid mimics, with important physico-chemical properties which have been exploited to develop a wide range of powerful biomolecular tools, including molecular probes, biosensors and anti-gene agents. New applications of PNA involve their use as hybridization probes, and consequently the PNA technology is now developing within the field of in situ hybridization techniques. Recent studies have reported the successful use of centromeric PNA probes on human lymphocytes, sperm as well as on isolated oocytes and blastomeres. Muticolour PNA protocols have been described for the specific identification of several human chromosomes. These data show that PNA could become a powerful complement to fluorescence in situ hybridization (FISH) for in situ chromosomal investigation, especially on isolated cells. The present paper gives an overview of the properties of PNA and the assays exploiting PNA technology in molecular genetics and cytogenetics.

Animals↗
PubMed2004

[Fetal and umbilical blood cord stem cells: a room for the obstetrician and gynaecologist. Part two].

Stem cells are undifferentiated cells, with the ability to self renew and to differentiate into specialised cells. Besides embryonic stem cells, adult, fetal and umbilical cord blood (UB) stem cells are to be distinguished. These cells are multipotent. Embryonic germ cells (EG) that also are fetal stem cells have proven to be truly pluripotent, since they are able to give derivatives of the three primitive embryonic layers. EG cells have a normal karyotype, and exhibit remarkable long-term proliferative potential. Fetal stem cells and UB cells have already been used in cell therapy trials (e.g., Parkinson's disease, congenital immunodeficiencies and hemopathies). The applications in the field of reproductive biology will lead to a better understanding of genomic imprinting with EG cells. The obstetrician and gynaecologist could act a central part in the production and study of fetal stem cells, using tissues from aborted fetuses or collecting cord blood stem cells.

Abortion, Induced↗
PubMed2004

[Embryonic stem cells: a position for the obstetrician and gynaecologist. Part one].

Stem cells are undifferentiated cells, with the ability to self renew and to differentiate into specialised cells. Embryonic stem cells (ES) have proven to be truly pluripotent, since they are able to give derivatives of the three primitive embryonic layers. Human ES have a normal karyotype, maintain high telomerase activity, and exhibit remarkable long-term proliferative potential, providing the possibility for unlimited expansion in culture. Though human ES cell-based transplantation therapy holds great promises to successfully treat a variety of diseases (e.g., Parkinson's disease, diabetes, and heart failure) many barriers remain in the way of successful clinical trials. Less spectacular, the applications in the field of reproductive biology are also outstanding: stem cell biology will lead us to a better understanding of the cellular and molecular mechanisms of events such as infertility, failure of implantation, genomic imprinting and meiosis. The obstetrician and gynaecologist could act an important part in the production and study of embryonic stem cells. However, these data have to be integrated in the ethical and juridical background of embryonic stem cell research in France.

Cell Differentiation↗
PubMed2003

First preimplantation genetic diagnosis of hereditary retinoblastoma using informative microsatellite markers.

Retinoblastoma is a malignant intra-ocular tumour of developing retina initiated by inactivation of both alleles of the retinoblastoma susceptibility (RB1) gene. This paper reports the first clinical experience of preimplantation genetic diagnosis (PGD) for hereditary retinoblastoma using two highly polymorphic microsatellite markers RB1.20 and D13S284, located within and close to the RB1 gene respectively. Duplex PCRs were tested on more than 300 single lymphocytes from heterozygous individuals at both loci, in order to test the accuracy and reliability of the single-cell protocol. This procedure requires a nested PCR and the analysis of fluorescently labelled PCR products on an automatic DNA sequencer. Amplification efficiency and allele drop-out rates ranged from 96.7 to 98.4%, and 3.7 to 5.4% respectively. This test was found to be accurate and reliable enough to be applied to the study of human blastomeres. Subsequently, this approach was used in a PGD treatment cycle for a couple who already had a child affected with hereditary retinoblastoma and found to be informative for both microsatellite markers.

Adult↗
PubMed2003

Specific detection of deleted and non-deleted dystrophin exons together with gender assignment in preimplantation genetic diagnosis of Duchenne muscular dystrophy.

We have developed a preimplantation genetic diagnosis (PGD) strategy for Duchenne muscular dystrophy (DMD) allowing the simultaneous amplification of four exons (6, 8, 28 and 32) of the dystrophin gene together with ZFX/ZFY genes for gender determination. Preliminary experiments were carried out on 215 single lymphocytes from male and female individuals. Amplification rates ranged from 90.2% for exon 6 to 96.7% for exons 8 and 32. At least four of the five sequences were successfully amplified in 95.8% of single cells, and sexing was possible in 98.5%. This 5-plex assay was found to be robust enough to be used in a PGD clinical procedure and was therefore applied to a family whose female partner was a heterozygous carrier of a large deletion extending from exon 21 to exon 34 of the dystrophin gene. We have thus analysed two exons located in the deleted region of the gene, two non-deleted exons used as intrasample controls, and ZFX/ZFY genes. Cleavage stage embryo biopsy followed by PCR resulted in transfer of three unaffected embryos. The advantage of the present approach is to identify and subsequently transfer unaffected male embryos in addition to female embryos, and is now applicable to all families displaying a deletion involving at least one of these exons.

Dystrophin↗
PubMed2002

[Preimplantation genetic diagnosis experience in Paris: evaluation of first births].

OBJECTIVE: To report the birth of the first fourteen infants conceived after preimplantation genetic diagnosis (PGD) in our unit. PATIENTS AND METHODS: Fifty-nine couples were enrolled between January 2000 and July 2001. They had a total of 71 oocyte pick-up cycles. The collected oocytes were inseminated by intracytoplasmic sperm injection. The resulting embryos were biopsied on the third day of development and the genetic analysis was performed on the same day. Most of the embryo transfers were carried out on the fourth day. RESULTS: The 71 oocyte pick-up cycles yielded 872 oocytes of which 731 were suitable for intacytoplasmic sperm injection. Among the 505 embryos obtained, 421 embryos were biopsied and genetic diagnosis was performed for 312 (74%) of these. 127 embryos were transferred during the course of 58 transfer procedures. There were 18 biochemical and 12 ongoing (7 singles, 4 twins and 1 triple) pregnancies. Fourteen infants have been born and 2 are expected. CONCLUSION: PGD has gained a place among the choices offered to couples at risk of transmission of a serious and incurable genetic disease.

Adult↗
PubMed2000

First specific preimplantation genetic diagnosis for ornithine transcarbamylase deficiency.

Ornithine transcarbamylase (OTC) deficiency is an X-linked dominant metabolic disorder with partial penetrance in heterozygous females. Affected boys usually die from hyperammonemia in the first few days of life, while clinical expression in carrier females ranges from no symptoms to neonatal death. A young couple whose boy had died of OTC deficiency in the neonatal period was referred to our genetic department for their subsequent pregnancy. The fetus was found to be affected, and after genetic counseling the pregnancy was terminated. Prenatal diagnosis of the third pregnancy identified a heterozygous female, who died after a normal birth at age 11 days from hyperammonemia. After this, the couple asked for preimplantation genetic diagnosis (PGD). We have developed a duplex nested PCR assay allowing the amplification of both the mutation and an informative restriction fragment length polymorphism (RFLP) located in the 3' end of the OTC gene. After nested amplification, allele identification was carried out for both loci by double restriction digestion and electrophoresis gel analysis. The co-amplification of both loci provided a means of detecting potential allele dropout or incomplete digestion. Two PGD cycles were carried out, a total of 14 embryos were analysed and a diagnosis could be obtained in 13/14 embryos. There were four unaffected male embryos, four heterozygous females and four unaffected females; the final embryo was an affected one of undetermined gender. In both cycles, three unaffected embryos could be transferred early on Day 4 post-insemination. The second cycle resulted in the birth of a baby boy devoid of the OTC mutation. This constitutes the first birth following PGD carried out by a French team.

Base Sequence↗
PubMed1999

Revival of the natural cycles in in-vitro fertilization with the use of a new gonadotrophin-releasing hormone antagonist (Cetrorelix): a pilot study with minimal stimulation.

Natural cycles were abandoned in in-vitro fertilization (IVF) embryo transfer, due to premature luteinizing hormone (LH) surges--and subsequent high cancellation rates. In this study, we investigated the administration of a new gonadotrophin-releasing hormone antagonist (Cetrorelix) in the late follicular phase of natural cycles in patients undergoing IVF and intracytoplasmic sperm injection (ICSI). A total of 44 cycles from 33 healthy women [mean age 34.1 +/- 1.4 (range 26-36) years] were monitored, starting on day 8 by daily ultrasound and measurement of serum concentrations of oestradiol, LH, follicle stimulating hormone (FSH) and progesterone. When plasma oestradiol concentrations reached 100-150 pg/ml, with a lead follicle between 12-14 mm diameter, a single injection (s.c.) of 0.5 mg (19 cycles) or 1 mg (25 cycles) Cetrorelix was administered. Human menopausal gonadotrophin (HMG; 150 IU) was administered daily at the time of the first injection of Cetrorelix, and repeated thereafter until human chorionic gonadotrophin (HCG) administration. Four out of 44 cycles were cancelled (9.0%). No decline in follicular growth or oestradiol secretion was observed after Cetrorelix administration. A total of 40 oocyte retrievals leading to 22 transfers (55%) was performed. In 10 cycles (25%), no oocyte was obtained. Fertilization failure despite ICSI occurred in six cycles (15%). In two patients the embryo was arrested at the 2 pronuclear (PN) stage. The stimulation was minimal (4.7 +/- 1.4 HMG ampoules). A total of seven clinical pregnancies was obtained (32.0% per transfer, 17.5% per retrieval), of which five are ongoing. Thus, a spontaneous cycle and the GnRH antagonist Cetrorelix in single dose administration could represent a first-choice IVF treatment with none of the complications and risks of current controlled ovarian hyperstimulation protocols, and an acceptable success rate.

Adult↗
PubMed1998

Pre or post-operative medical treatment with nafarelin in stage III-IV endometriosis: a French multicenter study.

OBJECTIVES: To determine the effectiveness of a 6-month course of nafarelin in the treatment of stage III-IV endometriosis and to determine if pre-operative use of nafarelin facilitates surgery. DESIGN: Prospective, multicenter, clinical trial. SETTING: Eight university hospitals and two private practice institutions in France. PATIENTS: Fifty-five patients with stage III and IV endometriosis. Two were excluded. INTERVENTIONS: The severity of endometriosis was assessed at the time of laparoscopy and patients were randomized to have either laparosopic surgery at that time following 6 months of nafarelin therapy (n=28), or laparoscopic surgery following 6 months of nafarelin therapy (n=25). All had 200 microg intranasal nafarelin twice a day for 6 months and a second look laparoscopy. MAIN OUTCOME MEASURE: Clinical efficacy, tolerance to the treatment. RESULTS: Efficacy and tolerance to the treatment were the same in both groups. AFS scores compared on both laparoscopies were significantly better if nafarelin was given prior to surgery (P=0.007). CONCLUSIONS: This preliminary study shows that in cases of combined medico-surgical treatment for stage III-IV endometriosis, preoperative medical treatment with GnRH-a gives a better AFS score improvement, but no conclusion was possible whether preoperative treatment facilitates surgery.

Adult↗
PubMed1998

Quantification by magnetic resonance spectroscopy of metabolites in seminal plasma able to differentiate different forms of azoospermia.

The aim was to determine whether proton magnetic resonance spectroscopy (1H-MRS) of metabolites such as glycerophosphorylcholine (GPC), choline, citrate and lactate in human seminal plasma can be used to differentiate (i) different azoospermic patients and (ii) different forms of spermatogenic failure including those who had undergone radiation therapy or chemotherapy. Semen samples were provided by men with obstructive azoospermia and spermatogenic failure who had serum follicle stimulating hormone (FSH) values within the normal range and either more or less than normal. Four prominent constituents of seminal plasma were identified by 1H-MRS: GPC, choline, citrate and lactate. The peak area ratios of choline/citrate as well as choline/lactate were significantly different (P < 0.01) between groups with spermatogenic failure and obstructive azoospermia. When the serum FSH values were normal in men with spermatogenic failure and obstructive azoospermia, a significant difference was found in the GPC/choline ratio (P < 0.001). When the FSH values were normal, the GPC/choline ratio appeared to be a very important parameter able to differentiate not only between cases of spermatogenic failure and obstructive azoospermia but also between different forms of spermatogenic failure. These results demonstrate the potential use of 1H-MRS on human seminal plasma in a new approach in the management of male infertility.

Antineoplastic Agents↗