Biomedical subjects
J Egozcue
Publications and source records attributed to J Egozcue.
Cytogenetic sexing of mouse embryos.
Cytogenetic sexing by means of chromosome C-banding was carried out in 1/2 and 2/4 biopsied mouse embryos. Chromosome spreads were obtained in 85.0% of 1/2-embryos and in 77.5% of 2/4-embryos. Sexing was accomplished in 30.0% of 1/2-embryos and 52.5% of 2/4-embryos, with a loss due to poor technique of 12.5 and 15.0% respectively. Transfer of sexed embryos resulted in a low implantation rate. The two live fetuses obtained were of the predicted sex.
Satellite polymorphism or Y/autosome translocation?
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Segregation analysis in a man heterozygous for a pericentric inversion of chromosome 7 (p13;q36) by sperm chromosome studies.
We have analyzed 140 sperm chromosome complements from a subfertile man heterozygous for an inv(7)(p13;q36). Seventy-five percent of the chromosome complements were not recombinant: 37.9% contained the normal chromosome 7, and 37.1% contained the inverted chromosome 7. Twenty-five percent of the 140 were recombinant: 7.1% carried a recombinant chromosome 7 with a duplication p and deletion q, 17.1% carried a recombinant chromosome 7 with a duplication q and deletion p, and 0.7% carried both recombinant chromosomes. The frequency of structural chromosomal aberrations unrelated to the inversion was 11.4%, and the frequency of aneuploidy was 2.9%. Both frequencies were not significantly different from those in control donors. Two sperm complements with a second independent, contiguous inversion involving one of the original breakpoints (q36) were observed (1.4%). The risk of producing chromosomally abnormal offspring or spontaneous abortions would be 34.3%. The proportion of X-bearing and Y-bearing sperm was 46.8% and 53.2%, respectively, not significantly different from the expected 1:1 ratio.
Cytogenetic studies in motile sperm from normal men.
Most studies on human sperm chromosomes from normal men involve the heterologous fertilization of zona free hamster eggs by unselected human sperm. In this work, we have performed cytogenetic studies of highly motile sperm, selected by a swim-up method. A total of 505 motile human sperm complements from three normal donors was analysed. The total frequency of sperm with chromosomal abnormalities (10.9%; 6.9% structural aberrations and 4.0% aneuploidy) and the sex ratio (50.4% X:49.6% Y) were similar to those obtained from whole semen samples. Our results indicate that the selection of motile sperm does not imply chromosomal selection.
Repair of human sperm chromosome aberrations in the hamster egg.
In order to study the repair capacity of fertilized hamster eggs for the lesions present or induced in human sperm, we have examined the potentiating effect of caffeine, a DNA repair inhibitor, on the frequency and types of sperm chromosome aberrations. Sperm samples were donated by an individual treated with chemotherapy for a testicular cancer 3 years previously. Exposure of spermatozoa and inseminated oocytes to caffeine led to an increase of sperm chromosome aberrations, indicating that the damage to human sperm can be repaired in untreated hamster egg cytoplasm. The potentiating effect of caffeine was mainly reflected in an increase of unrejoined aberrations, indicating that the formation of chromosomal rearrangements is also inhibited. Since both chromatid-type and chromosome-type aberrations increase after treatment with caffeine, damage to human sperm can probably be repaired inside the hamster egg cytoplasm by pre- and post-replication repair mechanisms.
Zona pellucida surface of immature and in vitro matured mouse oocytes: analysis by scanning electron microscopy.
PURPOSE: The aim of this work was to determine the morphology of the zona pellucida surface of immature and in vitro matured mouse oocytes by scanning electron microscopy. For this purpose two groups of immature oocytes (germinal vesicle group and metaphase I group) were studied either before or after in vitro maturation. RESULTS: Before in vitro maturation, the germinal vesicle immature group showed mainly an unstructured zona pellucida surface with smooth cumulus cells. The metaphase I immature group showed a more structured zona pellucida with smooth or blebbing cumulus cells. After in vitro maturation, development of the zona pellucida toward a mature surface, related to the initial degree of oocyte maturity, was observed in both groups. CONCLUSIONS: These observations show a correlation between the morphology of the zona pellucida surface and the degree of oocyte maturity; the in vitro maturation process can give rise to a proper development of this endowment when immature oocytes are used.
The genetic risks of in vitro fertilization techniques: the use of an animal model.
PURPOSE: The influence of some technical and biological parameters on the genetic characteristics of embryos derived from in vitro fertilization (IVF) techniques was studied. METHOD: Using a murine model, we assessed the effect of gamete manipulation, gamete maturation stage, and maternal age on the chromosome complements of first-cleavage embryos. RESULTS AND CONCLUSIONS: We found a positive correlation between some of these parameters and the incidence of the different chromosome abnormalities studied. Regarding aneuploidy, we observed an influence of maternal age, using both prepubertal and old females. Polyspermy showed a positive correlation with in vitro fertilization, the immaturity and overmaturity of the oocytes employed, and the use of prepubertal females. The appearance of diploid female complements was related to oocyte immaturity and prepubertal females, while diploid male complements were directly related to in vitro fertilization. Premature chromosome condensation (PCC) had a direct relationship with oocyte immaturity and in vitro maturation of the oocyte. Finally, structural abnormalities were associated with the process of sperm aging in vitro.
Cytogenetic studies in acute nonlymphocytic leukemia.
Cytogenetic studies were performed in 74 untreated patients with acute nonlymphocytic leukemia (ANLL) between 1985 and 1988. Among 56 patients who were examined successfully at the time of diagnosis, 36 had abnormal karyotypes (64.2%). The distribution of chromosome abnormalities was uneven, according to the categories of the French-American-British (FAB) nomenclature. The highest frequency of chromosome abnormalities was observed in ANLL M4 with bone marrow (BM) eosinophilia (M4Eo). Numerical changes were observed in 11 cases; chromosome 8 was most frequently gained (11 patients), whereas chromosome 7 was most frequently lost (4 patients). Structural rearrangements were detected in 18 patients. Involvement of 16q22 was noted in 7 patients, 5q- was noted in 5, t(8;21) in 3, t(1;7) in 2, del(20) in 2, and involvement of 11q23 was noted in 2. The inversion of chromosome 16 was restricted to the M4Eo subtype. This study identified a novel abnormality [inv(2) (p11.2q11.2)] that had not been reported previously by other investigators.
New chromosomal abnormality. t(1;19;?) in a case of B-chronic lymphocytic leukemia.
Cytogenetic analysis was performed on peripheral blood cells stimulated with interleukin 6 (IL-6), lipopolysaccharide from Escherichia coli (LPS), phytohemagglutinin (PHA), pokeweed mitogen (PWM) and tetradecanoyl-phorbol-acetate (TPA), in a patient with B-chronic lymphocytic leukemia, showing a t(1;19;?) translocation as the sole abnormality. To our knowledge, this translocation has not been described before in any human neoplasia. In this case, the poor response to therapy (survival time 4 months) suggested that t(1;19;?) could be related to an aggressive course of the disease.
Induction of premature centromere division affecting all chromosomes under culture conditions of fragile site expression.
In a study of chromosome fragility carried out under folate and thymidine deficiency conditions, we observed a seven- to ninefold increase of the incidence of premature centromere divisions (PCDs) affecting all chromosomes. This early separation of centromeres is clearly a culture effect and distinct from PCD and centromere splitting (CS), which imply a defect in the centromere of one or more chromosomes.
A method to extract DNA for molecular studies from cells fixed in Carnoy.
We describe a simple method for isolation of high-molecular-weight DNA from cells fixed in Carnoy's solution for cytogenetic studies. DNA samples were extracted from NIH3T3 cells, and no apparent degradation was noticed. This method should be useful for molecular analysis of cells fixed for cytogenetic studies.
Origin, development and ultrastructure of boar spermatozoa with folded tails and with two tails.
Spermatozoa from the three epididymal regions (head, body and tail) of healthy and sexually mature boars have been examined by light microscopy, and scanning and transmission electron microscopy. The origin, development and external and internal morphologies of aberrant spermatozoa with folded tails and spermatozoa with one or two heads and two fused tails have been established. A count carried out in each region of the epididymis indicated that significant differences (P less than 0.01) exist in the frequencies of each type of malformation and the epididymal region from which the spermatozoa come. Spermatozoa with folded tails at Jensen's ring originate in the cauda of the epididymis from immature spermatozoa that have not ejected the distal cytoplasmic droplet. The plasma membrane which covers the main piece is fused with the membranes of the midpiece, the connecting piece and the head. The fibrous sheath deforms the mitochondrial sheath and is placed between the plasma membrane and the postacrosomal dense lamina. Spermatozoa with one head and two fused tails originate in the epididymal body from spermatozoa with one head and two unfused tails coming from the cephalic region of the epididymis. Spermatozoa with two heads and two fused tails originate in the cephalic region of the epididymis by head-to-head agglutination of two spermatozoa and later fusion of their tails. The frequency of spermatozoa with two fused tails increases as they progress through the epididymal duct. Their tails, parallel in monocephalic spermatozoa and helicoid in bicephalic spermatozoa, have two complete axonemal axes. In their midpiece, the mitochondrial sheaths of the two axes are fused, producing an 8-shaped sheath.
Cytogenetic analysis of human oocytes form fertile women.
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Sequential and combined G-banding for identifying breakpoints in sister chromatid exchanges.
A simple new method is described for obtaining sequential and a combination of differential sister chromatid staining and G-banding in the same metaphase. Using this method the sister chromatid exchanges and chromosome lesion breakpoints can be precisely localized in particular bands of individual chromosomes.
[Origin of the extra chromosome 21 in Down's syndrome].
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Isochromosome 14q in myeloid dysplastic disorder.
A case of refractory anemia (RA) with an isochromosome 14q is described. This finding is compared with other hematologic disorders with trisomy 14 as the sole abnormality.
Effect of histamine on human lymphocyte aggregation.
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