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Jean Jacques Benet - One of the best experts on this subject based on the ideXlab platform.
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Segregation of chromosomes in sperm of reciprocal translocation carriers: a review.
Cytogenetic and Genome Research, 2005Co-Authors: Jean Jacques Benet, Maria Oliver-bonet, Patricio Cifuentes, Cristina Templado, Joaquima NavarroAbstract:Reciprocal translocations, the most frequent structural aberration in humans, are mainly transmitted by one of the parents. In order to analyze the chromosomal content of the spermatozoa from carriers of chromosomal reorganizations, two methods have been used, karyotyping of sperm chromosomes by the human-hamster system and fluorescence in situ hybridization (FISH) in decondensed sperm nuclei. In this work, we review 92 sperm chromosome Segregation studies from 85 different reciprocal translocation carriers, including a triple translocation carrier. Using the human-hamster method, a total of 5,818 spermatozoa from 44 reciprocal translocation carriers have been analyzed, 43 of them carrying a single reciprocal translocation and one was a carrier of a double reciprocal translocation. A Segregation analysis in a carrier of a t(2;22;11) has been also reported. Carrying out FISH in sperm nuclei, a total of 237,042 spermatozoa from 46 reciprocal translocation carriers have been analyzed. Six of these were also analyzed by the human-hamster system. Taking into account both methods, a total of 76 different reciprocal translocations have been studied. In 74 of these 76 translocations, the reorganization occurs between autosomes, and in the other two, the Y chromosome is involved. Although along general lines, there are similarities between the results obtained by the two methods of analysis, variations are observed when the distribution of the different types of Segregations that produce imbalances is compared. As a general rule reciprocal translocation carriers produce more unbalanced sperm than normal or balanced sperm. The results reported also corroborate that the proportion of unbalanced forms depends on the characteristics of the reorganization and that it varies widely. Thus the importance of performing a detailed meiotic behavior analysis for each particular translocation in order to obtain enough information to give adequate genetic counseling is stressed. Aspects as to the possible overestimation of 3:1 Segregations or the presence of interchromosomal effects still need to be elucidated.
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Meiotic Segregation analysis in a t(4;8) carrier: comparison of FISH methods on sperm chromosome metaphases and interphase sperm nuclei
European Journal of Human Genetics, 2001Co-Authors: Maria Oliver-bonet, Joaquima Navarro, Montserrat Codina-pascual, Marta Carrera, Josep Egozcue, Jean Jacques BenetAbstract:Meiotic Segregation of a t(4;8)(q28;p23) translocation carrier was determined by two different methods to compare the final results. A total of 352 sperm chromosome complements, obtained after human-hamster in vitro fertilisation, were analysed by whole chromosome painting, and 6590 sperm heads were studied by fluorescence in situ hybridisation (FISH). Frequencies of alternate, adjacent I, adjacent II and 3 : 1 Segregations were, for sperm chromosomes, 35.5, 33.2, 19.9 and 11.3% respectively. For sperm head analysis, results were 30.5, 28.5, 20.5 and 19.5% respectively. There were no statistically significant differences between the two methods with respect to the observed frequencies of sperm with balanced and unbalanced chromosome constitutions. Among unbalanced gametes, the methods differed only in the frequency of 3 : 1 Segregation (χ^2, P
Mary A Wells - One of the best experts on this subject based on the ideXlab platform.
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inverse and centreline Segregation formation in twin roll cast az31 magnesium alloy
Materials Science and Technology, 2015Co-Authors: Amir Hadadzadeh, Mary A WellsAbstract:Two microstructure defects formed in the twin roll cast AZ31 strips were investigated: inverse and centreline Segregations. A two-dimensional finite element thermal–fluid–stress model was employed to study the thermomechanical response of the AZ31 strip during twin roll casting process. The results showed that the key parameter for centreline Segregation is the mushy zone thickness at centreline. For inverse Segregation, the interaction between the yy peak stress at the centreline in the mushy zone and the solidified shell on the roll surface is the determinant parameter. The modelling results suggested increasing the setback distance decreases the risk of both defects. Moreover, scaling up the caster reduces the propensity to inverse Segregation but appears to have a minor effect for centreline Segregation formation.
Maria Oliver-bonet - One of the best experts on this subject based on the ideXlab platform.
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Segregation of chromosomes in sperm of reciprocal translocation carriers: a review.
Cytogenetic and Genome Research, 2005Co-Authors: Jean Jacques Benet, Maria Oliver-bonet, Patricio Cifuentes, Cristina Templado, Joaquima NavarroAbstract:Reciprocal translocations, the most frequent structural aberration in humans, are mainly transmitted by one of the parents. In order to analyze the chromosomal content of the spermatozoa from carriers of chromosomal reorganizations, two methods have been used, karyotyping of sperm chromosomes by the human-hamster system and fluorescence in situ hybridization (FISH) in decondensed sperm nuclei. In this work, we review 92 sperm chromosome Segregation studies from 85 different reciprocal translocation carriers, including a triple translocation carrier. Using the human-hamster method, a total of 5,818 spermatozoa from 44 reciprocal translocation carriers have been analyzed, 43 of them carrying a single reciprocal translocation and one was a carrier of a double reciprocal translocation. A Segregation analysis in a carrier of a t(2;22;11) has been also reported. Carrying out FISH in sperm nuclei, a total of 237,042 spermatozoa from 46 reciprocal translocation carriers have been analyzed. Six of these were also analyzed by the human-hamster system. Taking into account both methods, a total of 76 different reciprocal translocations have been studied. In 74 of these 76 translocations, the reorganization occurs between autosomes, and in the other two, the Y chromosome is involved. Although along general lines, there are similarities between the results obtained by the two methods of analysis, variations are observed when the distribution of the different types of Segregations that produce imbalances is compared. As a general rule reciprocal translocation carriers produce more unbalanced sperm than normal or balanced sperm. The results reported also corroborate that the proportion of unbalanced forms depends on the characteristics of the reorganization and that it varies widely. Thus the importance of performing a detailed meiotic behavior analysis for each particular translocation in order to obtain enough information to give adequate genetic counseling is stressed. Aspects as to the possible overestimation of 3:1 Segregations or the presence of interchromosomal effects still need to be elucidated.
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Meiotic Segregation analysis in a t(4;8) carrier: comparison of FISH methods on sperm chromosome metaphases and interphase sperm nuclei
European Journal of Human Genetics, 2001Co-Authors: Maria Oliver-bonet, Joaquima Navarro, Montserrat Codina-pascual, Marta Carrera, Josep Egozcue, Jean Jacques BenetAbstract:Meiotic Segregation of a t(4;8)(q28;p23) translocation carrier was determined by two different methods to compare the final results. A total of 352 sperm chromosome complements, obtained after human-hamster in vitro fertilisation, were analysed by whole chromosome painting, and 6590 sperm heads were studied by fluorescence in situ hybridisation (FISH). Frequencies of alternate, adjacent I, adjacent II and 3 : 1 Segregations were, for sperm chromosomes, 35.5, 33.2, 19.9 and 11.3% respectively. For sperm head analysis, results were 30.5, 28.5, 20.5 and 19.5% respectively. There were no statistically significant differences between the two methods with respect to the observed frequencies of sperm with balanced and unbalanced chromosome constitutions. Among unbalanced gametes, the methods differed only in the frequency of 3 : 1 Segregation (χ^2, P
M.m. Abramova - One of the best experts on this subject based on the ideXlab platform.
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Grain boundary Segregation induced strengthening of an ultrafine-grained austenitic stainless steel
Materials Letters, 2014Co-Authors: M.m. Abramova, N.a. Enikeev, Auriane Etienne, Bertrand Radiguet, Ruslan Z. Valiev, Yulia Ivanisenko, Xavier SauvageAbstract:Abstract The influence of grain boundary Segregation on the strength of a nanostructured austenitic stainless steel was investigated. The steel was nanostructured by severe plastic deformation at two different temperatures to form ultrafine-grained states different by microstructure parameters. It is shown that despite the difference in grain size both nanostructured steels demonstrated the same level of strength. For the first time it is directly observed that severe plastic deformation at elevated temperature leads to formation of Mo–Cr–Si rich grain boundary Segregations in the steel. Considering different contributions to the material strengthening, we demonstrate that grain boundary Segregations can lead to significant enhancement of the yield stress.
Renee H Martin - One of the best experts on this subject based on the ideXlab platform.
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analysis of human sperm chromosome complements from a male heterozygous for a reciprocal translocation t 11 22 q23 q11
Clinical Genetics, 2008Co-Authors: Renee H MartinAbstract:A reciprocal translocation between chromosomes 11 and 22 (t(11;22)(q23;q11] is a site-specific translocation that is of particular interest because of the propensity for 3:1 Segregation of the chromosomes during meiosis. There have been no published reports of chromosomally unbalanced offspring born as a result of adjacent 1 or 2 meiotic Segregations in a heterozygote for this translocation. This could be explained by a meiotic mechanism which produces only 3:1 chromosomal Segregations or by differential embryonic survival in which 2:2 adjacent Segregations do not produce a viable pregnancy. To distinguish between these two possibilities, sperm chromosome complements from a man heterozygous for this 11;22 translocation were studied. The human sperm chromosomes were analysed after fertilization of zona pellucida-free golden hamster eggs. All possible 2:2 (alternate, adjacent 1, adjacent 2) and 3:1 Segregations were observed and these Segregations occurred in approximately equal frequencies. The frequency of other chromosome abnormalities, unrelated to the translocation, did not appear to be increased. These results indicate that the 11;22 translocation does not specifically cause 3:1 disjunction of chromosomes but that this Segregation of chromosomes is more likely to result in a viable pregnancy.
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sperm chromosome complements in a man heterozygous for a reciprocal translocation 46 xy t 9 13 q21 1 q21 2 and a review of the literature
Clinical Genetics, 2008Co-Authors: Renee H Martin, Elizabeth L SpriggsAbstract:Sperm chromosome complements were studied in a man heterozygous for a reciprocal translocation t(9;13)(q21.1;q21.2). A total of 89 spermatozoa were karyotyped after in vitro penetration of hamster eggs. The frequencies of alternate, adjacent 1 and adjacent 2 Segregations were 46.9%, 35.8% and 17.3% respectively. For alternate Segregation, the number of normal spermatozoa (21) was not significantly different from the number of spermatozoa carrying a balanced form of the translocation (17), as theoretically expected. The proportion of spermatozoa with an unbalanced form of the translocation was 53.1%. There was no evidence for an interchromosomal effect since the frequency of numerical abnormalities (unrelated to the translocation) was within the normal range of control donors. Data from a total of 31 reciprocal translocations studied by sperm chromosomal analysis were reviewed.
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sperm chromosome complements from two human reciprocal translocation heterozygotes
Human Genetics, 1992Co-Authors: Elizabeth L Spriggs, Renee H Martin, Maj HultenAbstract:Using the hamster oocyte/human sperm fusion technique, we studied sperm chromosome complements in two male reciprocal translocation heterozygotes, 46,XY,t(11;17)(p11.2;q12.3) and 46,XY,t(1;11) (p36.3;q13.1). For the t(11;17) carrier, 202 sperm chromosome complements were obtained, but 18 karyotypes were not included in the Segregation data because of multiple breaks and rearrangements. The alternate and adjacent I types, adjacent II, and 3∶1 Segregations accounted for 38.6%, 32.1%, 26.6%, and 2.7% of the sperm analyzed from the t(11;17) carrier. A total of 575 sperm chromosome complements was obtained using sperm from the t(1;11) heterozygote, and 27 karyotypes were excluded from the Segregation data because of multiple breaks and rearrangements. For the t(1;11) carrier, the alternate and adjacent I types, adjacent II, and 3∶1 Segregations were responsible for 31.4%, 42.9%, 15.9%, and 8.0% of the analyzed sperm chromosome complements. Chromosomal abnormalities unrelated to the translocation, particularly the conservative estimate of aneuploidy frequency, were within the range observed in normal men. Hence, there was no evidence for an interchromosomal effect causing meiotic nondisjunction, despite the large sample sizes studied.
