Biomedical subjects

M Cristina Magli

Publications and source records attributed to M Cristina Magli.

12 recordsLinked to original sources

PubMed2006

Embryo morphology and development are dependent on the chromosomal complement.

OBJECTIVE: To analyze embryo morphology in relation to the corresponding chromosomal status, in order to evaluate the effects of aneuploidy over fragmentation, delayed cleavage, and arrested cleavage. DESIGN: Retrospective study. SETTING: Reproductive Medicine Unit, Società Italiana di Studi di Medicina della Riproduzione, Bologna, Italy. PATIENT(S): A total of 662 patients with a poor prognosis for pregnancy underwent 916 cycles of preimplantation genetic diagnosis for aneuploidy. INTERVENTION(S): The chromosomes XY, 13, 15, 16, 18, 21, and 22 were analyzed in blastomeres biopsied from day 3 embryos. MAIN OUTCOME MEASURE(S): Embryo morphology, chromosomal status of the analyzed blastomeres, and spreading and reanalysis of nontransferred embryos. RESULT(S): The incidence of chromosomal abnormalities was significantly higher in arrested or slow-cleaving embryos, and in embryos cleaving too fast, compared to embryos with eight cells at 62 hours after insemination. The presence of an uneven number of blastomeres or fragments scattered in the perivitelline space was associated with an increased incidence of chromosomal abnormalities. CONCLUSION(S): A correlation between embryo development and chromosomal complement makes the incidence of chromosomal abnormalities significantly higher in embryos dividing according to a time frame and a symmetry plan which are different from what are expected. The type of fragmentation is also related to chromosomal status, which explains why the extrusion of fragments might severely affect embryo viability.

Adult↗

PubMed2006

First meiosis errors in immature oocytes generated by stimulated cycles.

OBJECTIVE: To investigate chromosomal errors detected by first polar body (PB) biopsy in relation to the nuclear maturity of the oocytes. DESIGN: Retrospective study. SETTING: Reproductive medicine unit. PATIENT(S): Eighty-seven cycles were examined by PB biopsy for aneuploidy. Indications were maternal age >or=38 years (49 cycles), repeated IVF failures (22 cycles), and others (16 cycles). INTERVENTION(S): First polar bodies were analyzed for the chromosomes 13, 16, 18, 21, and 22 in both in vivo and in vitro matured oocytes. Euploid oocytes were inseminated by intracytoplasmic sperm injection. MAIN OUTCOME MEASURE(S): Chromosomal status of the analyzed oocytes, development after intracytoplasmic sperm injection, pregnancy, and implantation rates. RESULT(S): In in vitro matured oocytes, the proportion of chromosomal abnormalities was higher than in in vivo matured oocytes (70% vs. 54%, P<.005), with complex abnormalities being the prevailing defect (62% vs. 40%, P<.001). Conversely, the presence of an extra chromatid or the lack of a chromatid was more frequent in in vivo than in in vitro matured oocytes (55% vs. 34%, P<.001). CONCLUSION(S): The low viability of in vitro matured oocytes from stimulated cycles could be related to a significantly higher proportion of chromosomal abnormalities compared with in vivo matured oocytes. Complex abnormalities, involving two or more chromosomes, gave the strongest contribution to the detected increase.

Adult↗

PubMed2005

Frequency of aneuploidy in sperm from patients with extremely severe male factor infertility.

BACKGROUND: A protocol for the chromosomal analysis of sperm samples with a severely reduced number of sperm cells was designed. METHODS: A severe male factor condition was the main cause of infertility for 38 couples: 27 were oligoasthenoteratospermic (OAT) and 11 with non-obstructive azoospermia underwent testicular sperm extraction (TESE). A two-round fluorescence in situ hybridization (FISH) protocol was performed with probes specific for the chromosomes X, Y, 13, 15, 16, 17, 18, 21 and 22. The recording of the position of each sperm cell at the microscope allowed diagnosis of each spermatozoon for the nine tested chromosomes. RESULTS: A mean number of 122+/-78.5 sperm were diagnosed per patient with an incidence of total abnormalities corresponding to 13.4%. chi2-tests for the observed frequencies and goodness-of-fit test were highly significant in all cases. A significantly higher proportion of total aneuploidy was detected in 79% of the tested samples compared to the normal population. Testicular sperm were significantly more prone to aneuploidy than ejaculated sperm. CONCLUSIONS: The designed FISH protocol for the analysis of severe OAT and TESE sperm samples is reliable, implying that the studied sample is representative of the original population. In view of the high incidence of aneuploidy in most severe OAT and TESE sperm, the FISH analysis of pathological sperm samples can be routinely performed in order to estimate the chances of the paternal contribution to aneuploidy in the resulting embryos.

Adult↗

PubMed2005

L- and T-type voltage-gated Ca2+ channels in human granulosa cells: functional characterization and cholinergic regulation.

Using the whole-cell configuration of the patch-clamp technique, we have characterized two types of ionic currents through voltage-dependent Ca2+ channels in human granulosa cells. One is long-lasting, activates at approximately -20 mV, reaches the peak at approximately +20 mV, has an inactivation time constant of 132.5 +/- 5.6 msec at 20 mV, and is sensitive to dihydropyridines. The other is transient, activates at approximately -40 mV, peaks at approximately -10 mV, has an inactivation time constant of 38.8 +/- 1.8 msec at -10 mV, displays a voltage-dependent inactivation, and is sensitive to 100 microm Ni2+, but not to dihydropyridines. Biophysical and pharmacological properties of these currents indicate that they are gated through L- and T-type calcium channels, respectively. The cholinergic receptor agonist carbachol (50 microm) reduces the amplitude of the currents through both L-type (-34.7 +/- 6.4%; n = 10) and T-type (-52.6 +/- 7.4%; n = 8) channels, suggesting a possible role of these channels in the cholinergic regulation of human ovarian functions.

Calcium↗

PubMed2005

Effect of inner myometrium fibroid on reproductive outcome after IVF.

To evaluate the influence of inner myometrium fibroids (myomas) on the outcome of IVF cycles, a retrospective agematched controlled study was performed at SISMeR Reproductive Medicine Unit. The study group included 129 IVF/intracytoplasmic sperm injection cycles in 75 patients with one or more intramural and/or submucosal fibroids, while the control group consisted of 129 cycles in 127 patients without fibroids. The two groups were similar for mean oestradiol concentration at human chorionic gonadotrophin administration (1205.16 +/- 874 versus 1395 +/- 821 pg/ml), mean number of transferred embryos (2.02 +/- 0.4 versus 2.14 +/- 0.6) and clinical pregnancy rate (34.9 versus 41.1%). Conversely, the implantation rate was significantly lower in the study group (18.0%) than in the control group (26.5%; chi(2) = 4.81, P < 0.05), whereas the rate of spontaneous abortion demonstrated an opposite trend (40 versus 18.9%; chi(2) = 4.34, P < 0.05). Further research should be aimed at classifying fibroids on the basis of their location, especially when they are positioned in the junctional zone of the myometrium. Whether this classification will be superior in predicting the impact of fibroids on the reproductive outcome should be elaborated in a large multicentric study.

Abortion, Spontaneous↗

PubMed2005

The beneficial effects of preimplantation genetic diagnosis for aneuploidy support extensive clinical application.

The aim of this study was to evaluate the clinical impact of preimplantation genetic diagnosis (PGD) for aneuploidy on 193 patients who subsequently achieved 208 clinical pregnancies, in relation to their reproductive history. The 208 clinical pregnancies included in the study resulted from 1029 assisted conception cycles in combination with PGD for aneuploidy in 740 couples with a history of poor reproductive performance. According to the reproductive history of the 193 patients, 61 had previously experienced 112 pregnancies with 105 abortions and seven deliveries, corresponding to 3.6% take-home baby rate and 10.9% implantation rate. During the PGD cycle, preimplantation embryos were analysed for 5-9 chromosomes. The transfer of euploid embryos was performed in 699 cycles (68% of oocyte retrievals), generating 171 term pregnancies with 210 infants born, whereas 34 aborted spontaneously and three were ectopic, giving a take-home baby rate per pregnant patient of 88.6% and an ongoing implantation rate per pregnant patient of 53.2%. According to these data, selection made in preimplantation embryos against chromosomal abnormalities is associated with a significantly higher (P < 0.001) take-home baby rate when compared with the previous reproductive history of the parents.

Adult↗

PubMed2005

Sperm and blastomere aneuploidy detection in reproductive genetics and medicine.

The use of multiple probes in fluorescence in situ hybridization (FISH) permits the simultaneous analysis of several chromosomes in both blastomeres and spermatozoa. Preimplantation genetic diagnosis (PGD) for aneuploidy provides information on embryonic chromosomal status, enabling the selection of embryos carrying aneuploid condition. This strategy directly affects implantation, as documented for patients with a poor prognosis for pregnancy, who have the tendency to generate high proportions of chromosomally abnormal embryos. PGD for aneuploidy also has contributed information on early phases in human embryology by clarifying the molecular basis in some cases of irregular development. Multicolor FISH has also been used to study chromosomes on spermatozoa. Experimental strategies and modifications enabled the analysis of samples with a very low number of sperm cells, including samples retrieved from the genital tract or directly from the testicular tissue. The results confirmed that the incidence of aneuploidy increases proportionally with the severity of the male-factor condition. This observation suggests that, in selected cases, the paternal contribution to aneuploidy in the developing conceptus could be more relevant than expected from general data from aborted fetuses and live births.

Adult↗

PubMed2004

The combination of polar body and embryo biopsy does not affect embryo viability.

BACKGROUND: The biopsy of both polar bodies and a blastomere from the same embryo was investigated as an approach aimed at increasing the quantity of DNA available for genetic analysis in preimplantation embryos. METHODS: In 113 cycles, preimplantation genetic diagnosis (PGD) was performed for aneuploidy: 19 cycles underwent polar body biopsy, 32 cycles had both polar body and blastomere biopsy done, and the remaining 62 cycles underwent blastomere biopsy. The chromosomal analysis was performed in a two-round fluorescence in situ hybridization (FISH) protocol with probes specific for the chromosomes X, Y, 13, 15, 16, 18, 21 and 22. RESULTS: The morphological evaluation of the analysed embryos demonstrated similar rates of development irrespective of the biopsy procedure. Accordingly, the implantation rate did not differ significantly in the three biopsy groups and was 15% after polar body biopsy, 26% after the combined biopsy procedures of polar bodies and blastomeres, and 25% after blastomere biopsy. CONCLUSIONS: The removal of a blastomere subsequent to polar body biopsy does not seem to have negative effects on embryo viability. This approach could be especially valuable for a combined diagnosis of aneuploidy and single-gene disorders in preimplantation embryos generated by couples at high reproductive risk.

Adult↗

PubMed2003

Pronuclear morphology and chromosomal abnormalities as scoring criteria for embryo selection.

OBJECTIVE: To verify whether a correlation exists between pronuclear zygote morphology and the chromosomal condition of preimplantation embryos. DESIGN: Prospective analysis of pronuclear zygote morphology and preimplantation genetic diagnosis (PGD) for aneuploidy of the resulting embryos. SETTING: Reproductive medicine unit, day surgery clinic. PATIENT(S): Seventy-seven patients undergoing 107 PGD cycles because of advanced maternal age (77 cycles) or previous IVF failures (30 cycles). INTERVENTION(S): Evaluation of pronuclear zygote morphology and chromosomal condition of the resulting embryos. MAIN OUTCOME MEASURE(S): Rate of embryo development, proportion of euploid embryos, and distribution of chromosomal abnormalities. The position of pronuclei within the ooplasm, the size and distribution of nucleoli, and the orientation of polar bodies with respect to pronuclei were highly predictive for the presence of complex chromosomal abnormalities in the developing embryos; zygotes with juxtaposed pronuclei, large-size nucleoli, and polar bodies with small angles subtended by pronuclei and polar bodies were the configurations associated with the highest rates of euploidy. CONCLUSION(S): The combination of the patterns related to pronuclear zygote morphology indicated four configurations where the proportion of chromosomally normal embryos was significantly higher compared with the other configurations, suggesting the validity of this scoring system for the selection of embryos generated by PGD patients.

Adult↗

PubMed2002

The role of preimplantation diagnosis for aneuploidies.

The clinical application of preimplantation genetic diagnosis (PGD) for aneuploidy has confirmed the hypothesis that implantation failure and spontaneous abortions are frequently due to aneuploidy. Following PGD, a higher implantation rate and a lower incidence of spontaneous abortions are obtained in patient categories where aneuploidy is the main cause of reproductive failure: women in advanced reproductive age, patients with an altered karyotype due to translocations or gonosomal mosaicism, and patients with recurrent spontaneous abortions. In these cases, the transfer of euploid embryos overcomes the poor prognosis condition in these couples. As expected, aneuploidy increases proportionally with female age; however, not all the chromosomes studied show this trend, suggesting that segregation errors could occur at different rates for each chromosome in relation to maternal age. Furthermore, the retrospective analysis of the results obtained in patients who repeated at least twice a PGD cycle permitted to estimate their chances of reproducing the same pattern of chromosomal abnormalities and consequently evaluating their possibility of a pregnancy: when no euploid embryos are detected at the first attempt, the chance of on-term pregnancy is below 10%; however, this chance is approximately 30% for couples with at least two euploid embryos in the first cycle.

Abortion, Habitual↗

PubMed1996

Reducing the time of sperm-oocyte interaction in human in-vitro fertilization improves the implantation rate.

Human oocyte development was evaluated after a reduced time exposure to spermatozoa in vitro. A total of 119 patients were assigned to two study groups in a randomized prospective study in which each patient's oocytes were exposed to spermatozoa for either 1 h (group 1 - 58 patients) or the standard 16 h incubation period (group 2 - 61 patients). The fertilization rate obtained in group 1 was higher than in group 2 (285/393, 73%, and 272/410, 66% respectively), suggesting that the spermatozoa-oocyte interaction occurs within 1 h. This was confirmed in a study in vitro using fluorescently labelled spermatozoa and normal oocyte-cumulus complexes. Spermatozoa enter the cumulus complex within 15 min, traverse the cumulus layer within 3 h, and first appear in the oocyte cortex at 4 h post-insemination. The incidence of polyspermy was higher in oocytes exposed to spermatozoa for 16 h (3%) than for 1 h (1%). There was no difference in the cleavage rate or morphological characteristics of embryos from both study groups. However, when evaluating the timing of embryo development, group 1 generated a significantly higher percentage of four to five cell embryos when compared to group 2 (55 versus 39%; P < 0.001), documented at 40 h post-insemination. The implantation and pregnancy rates for group 1 were 11 and 28%, while the corresponding rates for group 2 were 8 and 15%. This suggests that a reduced exposure of oocyte to spermatozoa favours embryo viability, possibly due to a decrease in potential damage from sperm metabolic waste products.

Adult↗

PubMedDate not supplied

Impact of parental gonosomal mosaicism detected in peripheral blood on preimplantation embryos.

This study evaluated the chromosomal condition of embryos generated by patients with an altered karyotype due to gonosomal mosaicism and the clinical outcome after preimplantation genetic diagnosis (PGD) for aneuploidy. Thirty-six patients aged 34.6 +/- 3.6 years performed 54 treatment cycles and had 295 embryos diagnosed by fluorescence in-situ hybridization (FISH). Thirty-seven per cent of the embryos were chromosomally normal and generated 19 clinical pregnancies after replacement in 39 cycles. Only one pregnancy miscarried, yielding a take-home baby rate of 33.3%. Autosomal monosomy and trisomy contributed 36.1% of total abnormalities and gonosomal aneuploidy 5.9%, similar to the results detected in patients who undergo PGD for increased maternal age. Reanalysis was performed on 114 non-transferrable embryos: 41 were found to be mosaics, which were grouped in three different types, chaotic mosaics (56%), aneuploid mosaics (29%) and diploid/haploid/polyploid mosaics (15%). The incidence of aneuploid mosaics was higher than expected compared with PGD patients of the same age and resembled the condition observed in patients of advanced maternal age. These findings suggest that constitutional carriers of sex chromosome mosaicism are predisposed to autosomal mosaicism of embryos, possibly due to errors of cell division. There is an indication that this tendency is higher in female than male carriers.

Adult↗