Biomedical subjects

J Egozcue

Publications and source records attributed to J Egozcue.

At least 91 records · Page 5Linked to original sources

PubMed1999

Absence of chromosomal instability in spermatozoa of men affected by testicular cancer.

Testicular germ cell cancer affects mainly young men. It is the most frequent type of cancer in 20-35 year old men. Since cancer treatment using antineoplasic drugs and ionizing radiation has a negative effect on the function of the gonads, testicular cancer patients are offered the opportunity to cryopreserve their semen samples before the beginning of therapy. For this reason it would be of interest to know whether there is chromosome instability in their spermatozoa prior to any treatment. Using the interspecific human-hamster fertilization system, we have analysed a total of 340 chromosome complements from spermatozoa of control donors and 320 chromosome complements from testicular cancer patients. There were no significant differences in the frequencies of chromosomal aberrations between controls and cancer patients (9.7 and 10.3% respectively; P = 0.4921). Our results indicate that spermatozoa from untreated testicular cancer patients do not show an increased chromosomal instability as compared to control donors.

Adult↗

PubMed1999

Paternal sex chromosome aneuploidy as a possible origin of Turner syndrome in monozygotic twins: case report.

The meiotic or mitotic origin of most cases of Turner syndrome remains unknown, due to the difficulty in detecting hidden mosaicisms and to the lack of meiotic segregation studies. We have had the opportunity to study one pair of monozygotic twins concordant for Turner syndrome of paternal origin. The paternal origin of the single X chromosome was determined by polymerase chain reaction (PCR) amplification. No mosaicism was detected for the X or Y chromosome. In this case, a meiotic error during gametogenesis would be a likely origin of X monosomy. To determine if meiotic errors are more frequent in the father of these monozygotic twins concordant for Turner syndrome of paternal origin, molecular studies in spermatozoa were conducted to analyse sex chromosome numerical abnormalities. A total of 12520 sperm nuclei from the twins' father and 85338 sperm nuclei from eight normal donors were analysed using three-colour fluorescent in-situ hybridization. There were significant differences between the twins' father and control donors for XY disomy (0.22 versus 0.11%, P < 0.001) and total sex chromosome disomy (0.38 versus 0.21%, P < 0.001). These results could indicate an increased tendency to meiotic sex chromosome non-disjunction in the father of the Turner twins.

Adolescent↗

PubMed1999

Preliminary study of the incidence of disomy in sperm fractions after MicroSort flow cytometry.

Using triple colour fluorescent in-situ hybridization (FISH) we have evaluated, on a blind basis, the disomy level for chromosome 21 and the sex chromosomes in flow cytometric sorted sperm samples. There were no statistically significant differences in the disomy rates when comparing the sorted samples (either for X- or Y-bearing spermatozoa) with non-sorted samples. There were no diploid spermatozoa observed in any sample group after MicroSort processing.

Adult↗

PubMed1999

Meiotic abnormalities and spermatogenic parameters in severe oligoasthenozoospermia.

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.

Adult↗

PubMed1999

PCR protocol to detect parental origin and hidden mosaicism inSex chromosome aneuploidies.

In this study, we report an accurate method to determine the parental origin of sex chromosome aneuploidies or polyploidies and to detect low percentage mosaicisms. We have amplified by polymerase chain reaction (PCR) five polymorphic markers along the X chromosome (DXS1283E, DYS II, DMD49, AR and DXS52) and three markers along the Y chromosome (SRY, DYZ3 and DYZ1). False-negative results were discarded by the simultaneous amplification of Y markers and of internal controls. We have applied this protocol to a series of 14 Turner syndrome patients with a 45,X karyotype. We have detected sex chromosome mosaicisms in two patients. The parental origin of the syndrome has been determined in the other 12 patients.

Female↗

PubMed1998

[The cloning].

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Animals↗

PubMed1998

Chromosome abnormalities in peripheral blood lymphocytes from Macaca fascicularis and Erythrocebus patas (Cercopithecidae, Catarrhini) after X-ray irradiation.

In this paper, we describe the results of a qualitative and quantitative study of chromosomal reorganizations in X-irradiated (1 Gy and 2 Gy) lymphocytes from Macaca fascicularis (MFA) and Erythrocebus patas (EPA). A total of 515 breakpoints in M. fascicularis and 271 breakpoints in E. patas have been detected, identified and localized in the ideogram of the species. The Chi square test indicates that the distribution of breakpoints along the chromosomes is not random in M. fascicularis, and is not random for the p and q arms and bands in both species. Chromosome 5 of M. fascicularis (MFA5), chromosome 1 of E. patas (EPA1), and chromosome arms MFA5q, and EPA 1p are significantly more affected than expected, while chromosome MFA9 is less affected. Terminal regions of chromosome arms accumulate a higher number of breakpoints than the rest of the chromosome (44.4% in M. fascicularis and 45.98% in E. patas); 92.06% and 91.97% of breakpoints are observed in G negative bands in M. fascicularis and E. patas, respectively.

Animals↗

PubMed1998

Chromosome abnormalities in peripheral blood lymphocytes from Cebus apella (Cebidae, Platyrrhini) after X-ray irradiation.

In this paper, we describe the results of a qualitative and quantitative study of chromosomal reorganizations observed in X-irradiated (1Gy and 2Gy) and cultured lymphocytes from Cebus apella. A total of 646 breakpoints have been detected, identified and localized in the ideogram of the species. The breakpoint distribution along chromosomes, p and q arms, and bands is not random. Chromosomes #11, #12 and chromosome arms 1p, 12p, 13p, 15p, 11q, and 12q are significantly more affected than expected, while chromosome #19 and chromosome arm 19q are less affected. Terminal regions of chromosome arms accumulate a higher number of breakpoints than the rest of the chromosome (37.82%). A high percentage (93.66%) of breakpoints is found in G negative bands.

Animals↗

PubMed1998

Apolipoprotein E epsilon 4 alleles and meiotic origin of non-disjunction in Down syndrome children and in their corresponding fathers and mothers.

An increased risk of Alzheimer disease (AD) has been reported in young mothers of Down syndrome (DS) probands. Subsequently, an increased frequency of the apolipoprotein E (apoE) allele epsilon 4 has been found in mothers (< or = 32 years) of DS children due to meiosis II (MII) errors providing a potential explanation for the increased risk of AD in DS mothers. In the present study we genotyped apoE and determined the origin of non-disjunction of 132 mothers and the corresponding fathers and DS children from Spain. Unexpectedly no epsilon 4 alleles have been detected in MII mothers of < or = 32 years of age (P = 0.02). Thus our study not only fails to find the effect previously reported, but it detects an opposite correlation. An increase in the epsilon 4 frequency (0.227) is detected in MI mothers <28 as compared to the epsilon 4 frequency present in MI mothers >28 years of age (0.089), although the differences are not significant if correction for multiple comparisons is applied. The simplest overall interpretation of the previously reported and present findings is that the detected associations are due to random statistical variation rather than to some real effect of the epsilon 4 allele. However the important potential implications of alternative explanations imply that this issue deserves further clarification in independent studies in other populations.

Adolescent↗

PubMed1998

Unilateral spontaneous abdominal cryptorchidism: structural and ultrastructural study of sperm morphology.

Sperm morphology of three healthy boars and three boars with spontaneous abdominal cryptorchidism in the right testis has been evaluated by light microscopy. For each boar, two ejaculates have been analysed, corresponding to semen collections at the ages of 6.5 months (first collection) and 8 months (seventh collection). A comparative study of the sperm malformations present in the seventh semen collection between the healthy boars and the unilateral abdominal cryptorchid boars has also been performed by light microscopy. Sperm malformations of the seventh semen collection from the unilateral abdominal cryptorchid boars have been examined by scanning and transmission electron microscopy. The frequency of mature spermatozoa, immature spermatozoa, aberrant spermatozoa and detached heads maintained normals values in the first and the seventh semen collection from the unilateral abdominal cryptorchid boars. The comparative study of sperm abnormalities in the seventh semen collection between the cryptorchid boars and the healthy boars indicated that the unilateral abdominal cryptorchid boars had a significantly higher frequency of primary abnormalities, and a significantly lower frequency of secondary abnormalities. Some primary abnormalities, such as crater defect, knobbed acrosome defect, nuclear crests and abaxial tails were only observed in the unilateral abdominal cryptorchid boars. It was concluded that unilateral abdominal cryptorchidism provokes disturbances in the late stages of spermiogenesis, at testicular level. Alterations in the sperm maturation process at epididymal level were not found.

Animals↗

PubMed1998

Cytogenetic analysis using simultaneous and sequential fluorescence in situ hybridization.

A sequential fluorescence in situ hybridization (FISH) technique is described. This method allows the detection of up to eighteen chromosome pairs in consecutive hybridizations (8 steps) on the same metaphase using centromeric, whole chromosome painting, and single copy DNA probes with different fluorochromes. The technique may be used with diagnostic purposes in cases with poor cytogenetic material.

Cells, Cultured↗

PubMed1998

Plasma membrane and cytocortex alterations in frozen/thawed mouse embryos deprived of the zona pellucida.

We analyzed the morphological and ultrastructural abnormalities present in two-cell mouse embryos frozen/thawed without the zona pellucida (ZP). Transmission electron microscopy revealed that these embryos had plasma membrane abnormalities that were not observed in the embryos frozen/thawed with an intact ZP. The most frequent anomalies were a decreased number of microvilli with a nonhomogeneous distribution and showing an abnormal morphology and the presence of an increased number of vesicles in the periphery of the cell. The distribution of actin filaments, studied by fluorescence microscopy revealed alterations in both embryos, frozen/ thawed with ZP and embryos frozen/thawed without ZP: an increased staining in some regions of the peripheral actin band, discontinuities or gaps in the band, or the presence of a second actin band connected to the peripheral one.

Actins↗

PubMed1998

A new assay to asses aneuploidy in human-hamster embryos.

Fluorescent in situ hybridization using three chromosome-specific centromeric human DNA probes was used to analyze the aneuploidy frequency in human-hamster two-cell embryos. With these techniques first mitotic division errors due to the effects of physical or chemical agents on human spermatozoa, such as non-disjunction and anaphase lag, can be easily detected. In control samples the estimated frequency of non-disjunction and anaphase lag was 3.4%. This assay can also detect premeiotic or meiotic errors. We estimated the same frequency (3.4%) for disomy, whereas monosomy was not found.

Aneuploidy↗

PubMed1998

Effects on female fertility and germinal cells in prepubertal and adult rats (Rattus norvegicus) after X-ray irradiation.

In this work we analyse the effects of ionizing radiation in prepubertal and adult female rats, using as parameters, implantation sites, embryonic loss, and synaptonemal complex (SC) analysis of the female F1 of the pregnant rats. Our preliminary results show a decrease statistically significant in fertility of irradiated groups, but cytogenetic analysis did not shown any inherited damage attributed to radiation. At the same time, our results seem to indicate a higher resistance of oocytes from prepubertal rats and support the possible use of GnRH agonists as oestrus cycle suppressors to turn adult rats into gonadal quiescence.

Aging↗

PubMed1998

Recurrent in vitro fertilization failure evaluated by fluorescence in situ hybridization: a case report.

OBJECTIVE: To present a case of IVF failure evaluated by fluorescence in situ hybridization (FISH). DESIGN: Case report. SETTING: Research university laboratory and clinical IVF laboratory. PATIENT(S): An infertile couple with recurrent IVF failure. INTERVENTION(S): Fluorescence in situ hybridization study of the complete cohort of "zygotes" obtained at the third IVF attempt. MAIN OUTCOME MEASURE(S): Fluorescence in situ hybridization studies of chromosomes X, Y, 13, 18, and 21. RESULT(S): All the recovered putative zygotes were abnormal for the expected ploidy, presumably as a result of abnormal oocytes. CONCLUSION(S): Fluorescence in situ hybridization techniques represent a promising approach to analyze zygotes that fail to divide normally in vitro and eggs that fail to become fertilized. In cases of recurrent IVF failure, the results of FISH could be used to counsel couples and thus to help them choose among methods other than IVF for assisted reproduction.

Adult↗

PubMed1998

Analysis of 3p allelic losses in renal cell carcinomas: comparison with cytogenetic results.

We performed a study of loss of heterozygosity (LOH) at 3p by restriction fragment length polymorphism analysis in a series of 22 renal tumors. In 11 cases, molecular results could be compared with those of cytogenetic studies. The highest frequency of allelic losses at 3p was seen in clear cell non-papillary renal tumors, whereas none of the papillary renal cell carcinomas showed LOH at 3p. Allelic losses on 3p were found to be independent of tumor grade or stage or both. One case analyzed showed a discrepancy between cytogenetic and LOH studies. This tumor displayed rearrangements of chromosome 3 and no LOH at the c-RAF-1 (close to the Von Hippel Lindau gene) locus.

Carcinoma, Renal Cell↗

PubMed1998

FISH preimplantation diagnosis of chromosome aneuploidy in recurrent pregnancy wastage.

PURPOSE: Our purpose was to detect aneuploidy for chromosomes 13, 16, 18, 21, 22, X, and Y in preimplantation embryos from patients with a history of unexplained recurrent miscarriage. METHODS: Three patients with a history of unexplained recurrent spontaneous abortion were included in this study. Embryos were biopsied at the eight-cell stage, individually fixed on slides, and processed for fluorescent in situ hybridization (FISH). A multiple FISH protocol for seven chromosomes pairs (13, 16, 18, 21, 22, X, and Y) has been developed. RESULTS: A total of 39 embryos was studied with the multiple FISH protocol developed. Successful analysis of the biopsied embryos was achieved within the time limits usually allowed in a preimplantation diagnosis program. Analysis of the blastomeres showed that 17 embryos were chromosomally normal for the probes used, 16 embryos were aneuploid, and in 6 embryos no informative results were obtained. CONCLUSIONS: In the patients studied, a large proportion of embryos (41%) exhibited chromosomal abnormalities for the probes used. Preimplantation diagnosis to screen for chromosome abnormalities could be a feasible approach to improve the possibility of successful pregnancy in these couples.

Abortion, Habitual↗

PubMed1998

Relationship between the DNA content of human chromosomes and their involvement in radiation-induced structural aberrations, analysed by painting.

PURPOSE: To study the relationship between the DNA content of human chromosomes and their involvement in radiation-induced structural chromosome aberrations. MATERIAL AND METHODS: Human lymphocytes were cultured after exposure to 5 Gy of X-rays. FISH-painting was performed for all human chromosomes. RESULTS: The results indicate that with the exception of chromosome 20, there was a good fit between the DNA content and the number of exchange-type aberrations and the number of breaks. However, there was a significant tendency for short chromosomes to be more affected than expected and for long chromosomes to be less affected than expected. A better fit was observed when, instead of DNA content, the surface area of the chromosome territories obtained from a spherical model was taken into consideration. CONCLUSIONS: The tendency for short chromosomes to be more involved and long chromosomes to be less involved in exchange-type aberrations could be related not only to their DNA content but also to their interphase territory surface area.

Chromosome Aberrations↗