G Calderón

Publications (11)47.4 Total impact

• Source

  Available from: china-obgyn.net

  Article: Reliability of short comparative genomic hybridization in fibroblasts and blastomeres for a comprehensive aneuploidy screening: first clinical application.

  M Rius, A Obradors, G Daina, J Cuzzi, L Marquès, G Calderón, E Velilla, O Martínez-Passarell, M Oliver-Bonet, J Benet, J Navarro
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  ABSTRACT: Comparative genomic hybridization (CGH) is a valuable alternative to fluorescence in situ hybridization (FISH) for preimplantation genetic screening (PGS) because it allows full karyotype analysis. However, this approach requires the cryopreservation of biopsied embryos until results are available. The aim of this study is to reduce the hybridization period of CGH, in order to make this short-CGH technique suitable for PGS of Day-3 embryos, avoiding the cryopreservation step. Thirty-two fibroblasts from six aneuploid cell lines (Coriell) and 48 blastomeres from 10 Day-4 embryos, discarded after PGS by FISH with 9 probes (9-chr-FISH), were analysed by short-CGH. A reanalysis by the standard 72 h-CGH and FISH using telomeric probes was performed when no concordant results between short-CGH and FISH diagnosis were observed. The short-CGH was subsequently applied in a clinical case of advanced maternal age. In 100% of the fibroblasts analysed, the characteristic aneuploidies of each cell line were detected by short-CGH. The results of the 48 blastomeres screened by short-CGH were supported by both 72 h-CGH results and FISH reanalysis. The chromosomes most frequently involved in aneuploidy were 22 and 16, but aneuploidies for the other chromosomes, excepting 1, 10 and 13, were also detected. Forty-one of the 94 aneuploid events observed (43.6%) corresponded to chromosomes which are not analysed by 9-chr-FISH. We have performed a preliminary validation of the short-CGH technique, including one clinical case, suggesting this approach may be applied to Day-3 aneuploidy analysis, thereby avoiding embryo cryopreservation and perhaps helping to improve implantation rate after PGS.
  Human Reproduction 07/2010; 25(7):1824-35. · 4.47 Impact Factor
• Article: Meiotic abnormalities and spermatogenic parameters in severe oligoasthenozoospermia.

  J M Vendrell, F García, A Veiga, G Calderón, S Egozcue, J Egozcue, P N Barri
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  ABSTRACT: The incidence of meiotic abnormalities and their relationship with different spermatogenic parameters was assessed in 103 male patients with presumably idiopathic severe oligoasthenozoospermia (motile sperm concentration < or = 1.5 x 10(6)/ml). Meiosis on testicular biopsies was independently evaluated by two observers. Meiotic patterns included normal meiosis and two meiotic abnormalities, i.e. severe arrest and synaptic anomalies. A normal pattern was found in 64 (62.1%), severe arrest in 21 (20.4%) and synaptic anomalies in 18 (17.5%). The overall rate of meiotic abnormalities was 37.9%. Most (66.7%) meiotic abnormalities occurred in patients with a sperm concentration < or = 1 x 10(6)/ml. In this group, total meiotic abnormalities were found in 57.8% of the patients; of these, 26.7% had synaptic anomalies. When the sperm concentration was < or = 0.5 x 10(6)/ml, synaptic anomalies were detected in 40% of the patients. In patients with increased follicle stimulating hormone (FSH) concentrations, total meiotic abnormalities occurred in 54.8% (synaptic anomalies in 22.6%). There were statistically significant differences among the three meiotic patterns in relation to sperm concentration (P < 0.001) and serum FSH concentration (P < 0.05). In the multivariate analysis, sperm concentration < or = 1 x 10(6)/ml and/or FSH concentration > 10 IU/l were the only predictors of meiotic abnormalities.
  Human Reproduction 03/1999; 14(2):375-8. · 4.47 Impact Factor
• Source

  Available from: oxfordjournals.org

  Article: Ureteral lesion secondary to vaginal ultrasound follicular puncture for oocyte recovery in in-vitro fertilization.

  B Coroleu, F Lopez Mourelle, L Hereter, A Veiga, G Calderón, F Martinez, O Carreras, P N Barri
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  ABSTRACT: Techniques of oocyte retrieval have progressed from laparoscopy to transvaginal follicular aspiration under ultrasonographic control. This highly efficient method, routinely used nowadays, is not free of complications. We present a case of a ureteral lesion secondary to vaginal ultrasound follicular puncture for oocyte recovery in in-vitro fertilization. Despite the surgical procedure to reimplant the ureter, the patient achieved a twin pregnancy which is ongoing uneventfully.
  Human Reproduction 06/1997; 12(5):948-50. · 4.47 Impact Factor
• Article: Intracytoplasmic sperm injection versus conventional in-vitro fertilization: first results.

  G Calderón, I Belil, B Aran, A Veiga, Y Gil, M Boada, F Martinez, N Parera, B Coroleu, J Penella
  Human Reproduction 12/1995; 10(11):2835-9. · 4.47 Impact Factor
• Article: Evaluation of cytogenetic analysis for clinical preimplantation diagnosis.

  J Santaló, A Veiga, J M Calafell, G Calderón, F Vidal, P N Barri, C Giménes, J Egozcue
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  ABSTRACT: To evaluate the feasibility of using cytogenetic analysis in preimplantation diagnosis. Two different biopsy protocols (chemical drilling and zona cutting) and two fixation methods were tested in a mouse model. Afterwards, the efficiency of obtaining chromosome preparations from untransferable human embryos depending on the method used to obtain the blastomeres (embryos biopsy or removal of the zona pellucida and blastomere disaggregation) was determined. The chances of obtaining chromosome preparations depending on the type of embryo (haploid, diploid, triploid, and apparently unfertilized) were also evaluated. Results from the mouse model showed that chemical drilling yields better results than cutting in terms of metaphases per biopsied embryo and surviving rate after biopsy. In human embryos, biopsy of diploid embryos produced 46.6% chromosome preparations, while 29% were obtained after blastomere disaggregation and 20.4% when biopsying triploid embryos. These results suggest that the disaggregating procedure and triploid embryos cannot be considered as good models to assess the feasibility of cytogenetic analysis in preimplantation diagnosis. Poor chromosome quality and loss during fixation are the main problems to use cytogenetics in preimplantation diagnosis; a combination of cytogenetics and other techniques is suggested in cases of balanced translocations.
  Fertility and Sterility 08/1995; 64(1):44-50. · 3.56 Impact Factor
• Article: Twin pregnancy after preimplantation diagnosis for sex selection.

  A Veiga, J Santaló, F Vidal, G Calderón, C Giménez, M Boada, J Egozcue, P N Barri
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  ABSTRACT: A twin female pregnancy was obtained in a haemophilia carrier after two preimplantation diagnosis cycles. The embryonic sex of biopsied blastomeres was determined with the use of dual fluorescence in-situ hybridization with directly labelled DNA probes specific for the X and Y chromosome. A twin female pregnancy was confirmed by means of ultrasonography and amniocentesis at the 14th week of amenorrhoea. The patient delivered two healthy females by Caesarian section at the 37th week of pregnancy.
  Human Reproduction 12/1994; 9(11):2156-9. · 4.47 Impact Factor
• Article: Sephadex filtration and human serum albumin gradients do not select spermatozoa by sex chromosome: a fluorescent in-situ hybridization study.

  F Vidal, M Moragas, V Català, M J Torelló, J Santaló, G Calderón, C Gimenez, P N Barri, J Egozcue, A Veiga
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  ABSTRACT: Fluorescent in-situ hybridization (FISH) of decondensed sperm nuclei has been used directly to evaluate the enrichment efficiency of human sperm separation using Sephadex gel filtration and human serum albumin (HSA) gradients. Control and processed spermatozoa were fixed and their nuclei decondensed. In-situ hybridization was carried out with a Y-specific DNA probe (DYZ1). Sephadex filtration yielded 52.5% Y-chromosome-bearing spermatozoa, HSA separation resulted in 49.4% Y-chromosome-bearing spermatozoa and in the untreated control sample the percentage of Y spermatozoa was 49.3%. Statistical analysis revealed no significant differences between the selection methods employed and the controls, and no real enrichment for X- or Y-bearing spermatozoa was detected for any of the selection methods assayed. The usefulness of the protocols reported for selection of spermatozoa by sex chromosome in couples at risk for X-linked diseases is discussed.
  Human Reproduction 11/1993; 8(10):1740-3. · 4.47 Impact Factor
• Article: Two years of assisted fertilization by partial zona dissection in male factor infertility patients.

  G Calderón, A Veiga, J Penella, P N Barri
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  ABSTRACT: To assess partial zona dissection in our routine IVF-ET program over a 2-year period. Partial zona dissection before insemination on the day of oocyte collection or 24 hours after unsuccessful conventional IVF. In a subgroup of patients, oocytes were randomized to either partial zona dissection before insemination or IVF. University infertility clinic. Couples who suffered principally from male factor infertility or who had failed fertilization previously. Micromanipulation of oocytes with partial zona dissection. Comparison of fertilization rate, embryo morphology, and implantation rate between partial zona dissection inseminated oocytes and conventional IVF inseminated oocytes (controls). Five pregnancies were established in 199 patients. The incidence of polyspermy was significantly higher in the partial zona dissection group than in conventional IVF (4.8% versus 1.3%). There were no significant differences in the remaining parameters. The fertilization rate of partial zona dissection and reinsemination was significantly higher than conventional IVF insemination (13.6% versus 4.5%) but similar to the rate obtained when partial zona dissection was applied before insemination (13.6% versus 15.7%). Oocytes treated by partial zona dissection did not exhibit a greater fertilization rate than conventional IVF inseminated oocytes. Partial zona dissection may not be a useful technique for treating severe male factor infertility.
  Fertility and Sterility 08/1993; 60(1):105-9. · 3.56 Impact Factor
• Article: Chromosome anomalies in mouse zygotes treated by growth hormone-releasing factor.

  B Arán, G Calderón, M Moragas, M J Torelló, A Veiga, P N Barri
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  ABSTRACT: The incidence of chromosome anomalies was studied in fertilized oocytes in two groups of hybrid mice in which superovulation was induced by gonadotrophins and growth hormone-releasing factor (GRF) supplementation or gonadotrophins alone (controls). The rate of fertilization was significantly higher among GRF-treated females than among controls (74.1 versus 84.7%; P < 0.013). Cytogenetic data were obtained in 262 fertilized oocytes (89 from control females and 173 from GRF-treated females). The frequency of aneuploidy, calculated as twice the frequency of hyperhaploidy was 2.31% in GRF-treated females and 2.24% in controls (NS). The use of GRF to treat female mice did not adversely affect the maturation process of oocytes nor did it induce an increased frequency of aneuploidy.
  Human Reproduction 11/1992; 7(10):1394-5. · 4.47 Impact Factor
• Article: Indications for oocyte donation.

  P N Barri, B Coroleu, F Martinez, N Parera, A Veiga, G Calderón, M Boada, I Belil
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  ABSTRACT: Donated oocytes were transferred on 92 occasions to 87 women without gonadal function and 5 with functional ovaries. Twenty-three pregnancies were established (25% pregnancy rate), 9 after transfer of fresh embryos in 30 synchronous donor and recipient cycles and 14 after transfers of frozen-thawed embryos in 62 asynchronous donor and recipient cycles. Twenty-two pregnancies were obtained in agonadal patients (25.3% pregnancy rate) and 1 in a gonadal woman (20% pregnancy rate). Pregnant women were younger than those who did not become pregnant, but the difference was not significant. The pregnancy rate was higher when intra-Fallopian transfer was performed (46%) as compared with intrauterine transfer (21.5%) and when micronized progesterone was given intravaginally (pregnancy rate 30.3%) as compared to intramuscularly injected natural progesterone in oil (pregnancy rate 22%). Twenty healthy infants have been born including one set of twins; four pregnancies miscarried.
  Human Reproduction 07/1992; 7 Suppl 1:85-8. · 4.47 Impact Factor
• Article: Chromosome studies in oocytes and zygotes from an IVF programme.

  A Veiga, G Calderón, J Santaló, P N Barri, J Egozcue
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  ABSTRACT: Chromosome studies have been carried out in 117 oocytes, 17 one-cell zygotes and four, two- to four-cell zygotes in our IVF programme. Three apparently unfertilized oocytes were, in fact, diploid zygotes. Two of 14 apparently polyspermic zygotes were also diploid. One zygote with four pronuclei was pentaploid. This indicates that pronuclei can either be confused with other cytoplasmic structures, like vacuoles, or be eliminated. Endoreduplication was observed in one tetraploid, apparently polyspermic zygote, and in one two-cell degenerated zygote. The incidence of aneuploidy in unfertilized oocytes, taken as twice the level of hyperhaploidy, was 15.4%. Five oocytes showed fragmented metaphase II chromosomes (4.3%). The incidence of unreduced oocytes, due to a lack of extrusion of the first polar body, was 6.8%. Thus the total number of potentially aneuploid, polyploid or non-viable zygotes due to chromosome aberrations in the oocyte was 26.5%.
  Human Reproduction 08/1987; 2(5):425-30. · 4.47 Impact Factor